JP7647965B2 - Packaging film for power storage device and power storage device - Google Patents

Description

This disclosure relates to packaging films for electricity storage devices and electricity storage devices.

Various types of electricity storage devices have been developed, but in all electricity storage devices, exterior materials are essential components for sealing the electricity storage device elements such as electrodes and electrolytes. Traditionally, metal exterior materials have been widely used as packaging films for electricity storage devices.

On the other hand, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like, there is a demand for electricity storage devices to have a variety of shapes, as well as to be thinner and lighter. However, the metal packaging films for electricity storage devices that have been widely used in the past have the disadvantage that they are difficult to keep up with the diversification of shapes, and there is also a limit to how much they can be made lighter.

In recent years, a film-like laminate in which a base layer, a metal layer, and a heat-sealable resin layer are laminated in this order has been proposed as a packaging film for electricity storage devices that can be easily processed into a variety of shapes and can be made thinner and lighter (see, for example, Patent Document 1).

In such packaging films for electricity storage devices, recesses are generally formed by cold forming, electricity storage device elements such as electrodes and electrolyte are placed in the space formed by the recesses, and the heat-sealable resin layer is heat-sealed to obtain an electricity storage device in which the electricity storage device elements are housed inside the packaging film for electricity storage devices.

JP 2008-287971 A

(First aspect)
In the manufacturing process of an electricity storage device, generally, an electricity storage device element is accommodated in a packaging film for an electricity storage device, and then temporarily sealed, and an initial charge/discharge process, an aging process, etc. are performed. In these processes, it is known that gases such as _CO2 are generated from the electricity storage device element, and in order to provide a space for holding the gas inside the temporarily sealed package (made of a packaging film for an electricity storage device), and further to remove the space holding the gas and release the gas to the outside, the electricity storage device is currently manufactured using a packaging film for an electricity storage device that is larger than the size required for the final product of the electricity storage device (for example, more than twice the size required for sealing the electricity storage device element).

The inventors of the present disclosure have created a problem of providing new value by imparting _CO2 permeability to a packaging film for an electricity storage device.

A primary object of a first aspect of the present disclosure is to provide a packaging film for an electricity storage device having a predetermined _CO2 permeability.

(Second Aspect)
Furthermore, a metal terminal protrudes from the heat-sealed portion of the packaging film for electricity storage devices, and the electricity storage device element sealed with the packaging film for electricity storage devices is electrically connected to the outside by the metal terminal electrically connected to the electrode of the electricity storage device element. That is, among the heat-sealed portions of the packaging film for electricity storage devices, the portion where the metal terminal is present is heat-sealed in a state where the metal terminal is sandwiched between the heat-sealable resin layer. Since the metal terminal and the heat-sealable resin layer are made of different materials, adhesion is likely to decrease at the interface between the metal terminal and the heat-sealable resin layer.

In addition, by not providing a metal layer in the packaging film for electricity storage devices, there is the advantage that the packaging film can be made thinner and lighter.

The inventors of the present disclosure have created a problem that provides new value by combining the advantage of adhesion to metal with the advantage of not having a metal layer in a packaging film for electricity storage devices.

The second aspect of the present disclosure has as its main objective the provision of a packaging film for an electricity storage device that has adhesion to metal and does not have a metal layer formed from metal.

(Third Aspect)
In the manufacturing process of the electricity storage device, generally, after the electricity storage device element is accommodated in the packaging film for the electricity storage device, the periphery of the packaging film for the electricity storage device is sealed to temporarily seal it. Then, an initial charge/discharge process and an aging process are performed. The packaging film for the electricity storage device provided in the secondary battery includes a metal layer and therefore has a shielding property. Therefore, when the electricity storage device element is sealed by the packaging film for the electricity storage device, it is not possible to check whether the periphery of the packaging film for the electricity storage device is properly sealed. Therefore, the electricity storage device cannot be manufactured suitably.

The third aspect of the present disclosure aims to provide a method for manufacturing an electricity storage device that can suitably manufacture an electricity storage device, and an electricity storage device manufactured by this manufacturing method.

(Fourth aspect)
In the manufacturing process of an electric storage device, generally, after an electric storage device element is accommodated in a packaging film for an electric storage device, the periphery of the packaging film for an electric storage device is sealed to temporarily seal the device. Then, an initial charge/discharge process and an aging process are performed. In these processes, it is known that gases such as _CO2 are generated from the electric storage device element, and in order to provide a space for holding the gas inside the temporarily sealed package (made of a packaging film for an electric storage device), and further to remove the space in which the gas is held and release the gas to the outside, the electric storage device is currently manufactured using a packaging film for an electric storage device that is larger than the size required for the electric storage device that will ultimately be the product (for example, more than twice the size required for sealing the electric storage device element). For this reason, the manufacturing process of the electric storage device is complicated.

The fourth aspect of the present disclosure aims to provide a method for easily manufacturing an electricity storage device, and an electricity storage device manufactured by this manufacturing method.

(Fifth aspect)
In addition to the functions that electricity storage devices usually have, it is preferable that the electricity storage device has a function with high added value.

The fifth embodiment of the present disclosure aims to provide an electricity storage device with high added-value functions.

(First aspect)
A first aspect of the present disclosure provides the invention having the following aspects.
A packaging film for an electricity storage device comprising at least a heat-sealable resin layer,
A packaging film for an electricity storage device, having a _CO2 permeation amount of 100 cc·100 μm/ ^m2 /24 hr/atm or more in an environment at a temperature of 30°C.

(Second Aspect)
A second aspect of the present disclosure provides the invention having the following aspects.
A packaging film for an electricity storage device comprising at least a heat-sealable resin layer,
The packaging film for an electricity storage device has adhesiveness to metal,
The packaging film for an electricity storage device does not have a metal layer formed from a metal.

(Third Aspect)
A manufacturing method for an electricity storage device according to a first aspect of the third aspect of the present disclosure is a manufacturing method for an electricity storage device, the electricity storage device comprising an electricity storage device element and an inner packaging body that houses the electricity storage device element, the inner packaging body being constituted by a transparent packaging film for an electricity storage device, and the method includes an inner packaging step of wrapping the electricity storage device element with the packaging film for an electricity storage device, and an inner sealing step that is performed after the inner packaging step and seals the packaging film for an electricity storage device so that the electricity storage device element is hermetically sealed by the packaging film for an electricity storage device.

The method for producing an electricity storage device according to the second aspect of the third aspect of the present disclosure is the method for producing an electricity storage device according to the first aspect, in which the packaging film for the electricity storage device further has gas permeability, and further includes a degassing step that is carried out after the inner sealing step and releases gas generated from the electricity storage device element through the packaging film for the electricity storage device.

The method for manufacturing an electricity storage device according to the third aspect of the third aspect of the present disclosure is the method for manufacturing an electricity storage device according to the second aspect, in which in the inner packaging step, the electricity storage device element is wrapped in the electricity storage device packaging film that is substantially the same size as the inner packaging body of the finished electricity storage device.

The electric storage device according to the fourth aspect of the third aspect of the present disclosure comprises an electric storage device element, an inner packaging body that houses the electric storage device element, and an outer packaging body that houses the inner packaging body in which the electric storage device element is housed, and the inner packaging body is made of a transparent packaging film for electric storage devices.

The fifth aspect of the third aspect of the present disclosure is the fourth aspect of the electric storage device, further comprising a metal terminal electrically connected to the electric storage device element and a tab film disposed between the inner packaging body and the metal terminal, the outer packaging body being joined to the inner packaging body, the inner packaging body being joined to the metal terminal via the tab film, and at least a portion of the outer edge of the inner packaging body being exposed from the outer packaging body.

The sixth aspect of the third aspect of the present disclosure is the electric storage device according to the fourth aspect, further comprising a metal terminal electrically connected to the electric storage device element, and a tab film disposed between the inner packaging body and the outer packaging body and the metal terminal, the inner packaging body and the outer packaging body being joined to the metal terminal via the tab film, and the entire inner packaging body being covered by the outer packaging body.

The seventh aspect of the third aspect of the present disclosure is the energy storage device according to the fourth aspect, further comprising a metal terminal electrically connected to the energy storage device element, the inner packaging body and the metal terminal are joined, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The electric storage device according to the eighth aspect of the third aspect of the present disclosure is the electric storage device according to the fourth aspect, further comprising a metal terminal electrically connected to the electric storage device element, the inner packaging body and the outer packaging body are joined to the metal terminal, and the entire inner packaging body is covered by the outer packaging body.

The electricity storage device according to the ninth aspect of the third aspect of the present disclosure is an electricity storage device according to any one of the third to eighth aspects, in which the packaging film for the electricity storage device further has gas permeability.

(Fourth aspect)
A manufacturing method for an electricity storage device according to a first aspect of the fourth aspect of the present disclosure is a manufacturing method for an electricity storage device, the electricity storage device comprising an electricity storage device element and an inner packaging body that houses the electricity storage device element, the inner packaging body being constituted by a packaging film for an electricity storage device having gas permeability, and the method includes an inner packaging step of wrapping the electricity storage device element with the packaging film for an electricity storage device, an inner sealing step that is performed after the inner packaging step of sealing the packaging film for an electricity storage device so that the electricity storage device element is hermetically sealed by the packaging film for an electricity storage device, and a degassing step that is performed after the inner sealing step of releasing gas generated from the electricity storage device element through the packaging film for an electricity storage device.

The method for manufacturing an electricity storage device according to the second aspect of the fourth aspect of the present disclosure is the method for manufacturing an electricity storage device according to the first aspect, in which in the inner packaging step, the electricity storage device element is wrapped in the electricity storage device packaging film that is substantially the same size as the inner packaging body of the finished electricity storage device.

The electricity storage device according to the third aspect of the fourth aspect of the present disclosure comprises an electricity storage device element, an inner packaging body that houses the electricity storage device element, and an outer packaging body that houses the inner packaging body in which the electricity storage device element is housed, and the inner packaging body is composed of a gas-permeable packaging film for electricity storage devices.

The fourth aspect of the fourth aspect of the present disclosure is an electric storage device according to the third aspect, further comprising a metal terminal electrically connected to the electric storage device element and a tab film disposed between the inner packaging body and the metal terminal, the outer packaging body being joined to the inner packaging body, the inner packaging body being joined to the metal terminal via the tab film, and at least a portion of the outer edge of the inner packaging body being exposed from the outer packaging body.

The electric storage device according to the fifth aspect of the fourth aspect of the present disclosure is the electric storage device according to the third aspect, further comprising a metal terminal electrically connected to the electric storage device element, and a tab film disposed between the inner packaging body and the outer packaging body and the metal terminal, the inner packaging body and the outer packaging body being joined to the metal terminal via the tab film, and the entire inner packaging body being covered by the outer packaging body.

The sixth aspect of the fourth aspect of the present disclosure is the electricity storage device according to the third aspect, further comprising a metal terminal electrically connected to the electricity storage device element, the inner packaging body and the metal terminal are joined, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The seventh aspect of the fourth aspect of the present disclosure is an electricity storage device according to any one of the third to sixth aspects, in which the packaging film for the electricity storage device further has transparency.

(Fifth aspect)
The energy storage device according to a first aspect of the fifth aspect of the present disclosure comprises an energy storage device element, an inner packaging body that houses the energy storage device element, an outer packaging body that houses the inner packaging body in which the energy storage device element is housed, and a functional object that is arranged between the inner packaging body and the outer packaging body, and the functional object has impact absorption properties.

The energy storage device according to the second aspect of the fifth aspect of the present disclosure comprises an energy storage device element, an inner packaging body that houses the energy storage device element, an outer packaging body that houses the inner packaging body in which the energy storage device element is housed, and a functional object that is disposed between the inner packaging body and the outer packaging body, and the functional object has flame retardancy.

The energy storage device according to the third aspect of the fifth aspect of the present disclosure comprises an energy storage device element, an inner packaging body that houses the energy storage device element, an outer packaging body that houses the inner packaging body in which the energy storage device element is housed, and a functional object that is disposed between the inner packaging body and the outer packaging body, and the functional object has a cooling property.

The electric storage device according to the fourth aspect of the fifth aspect of the present disclosure comprises an electric storage device element, an inner packaging body that houses the electric storage device element, an outer packaging body that houses the inner packaging body in which the electric storage device element is housed, and a functional object that is disposed between the inner packaging body and the outer packaging body, and the functional object has fire extinguishing properties.

The electricity storage device according to the fifth aspect of the fifth aspect of the present disclosure comprises an electricity storage device element, an inner packaging body that houses the electricity storage device element, and an outer packaging body that houses the inner packaging body in which the electricity storage device element is housed, and at least one of the inner packaging body and the outer packaging body has at least one of shock absorption, flame retardancy, cooling properties, and fire extinguishing properties.

The sixth aspect of the fifth aspect of the present disclosure is an electricity storage device according to any one of the first to fifth aspects, in which the inner packaging body has at least one of transparency and gas permeability.

The seventh aspect of the fifth aspect of the present disclosure is an electricity storage device according to any one of the first to sixth aspects, further comprising a metal terminal electrically connected to the electricity storage device element and a tab film disposed between the inner packaging body and the metal terminal, the outer packaging body being joined to the inner packaging body, the inner packaging body being joined to the metal terminal via the tab film, and at least a portion of the outer edge of the inner packaging body being exposed from the outer packaging body.

The electric storage device according to the eighth aspect of the fifth aspect of the present disclosure is an electric storage device according to any one of the first to sixth aspects, further comprising a metal terminal electrically connected to the electric storage device element, and a tab film disposed between the inner and outer packaging bodies and the metal terminals, the inner and outer packaging bodies being joined to the metal terminals via the tab film, and the entire inner packaging body being covered by the outer packaging body.

The electricity storage device according to the ninth aspect of the fifth aspect of the present disclosure is an electricity storage device according to any one of the first to sixth aspects, further comprising a metal terminal electrically connected to the electricity storage device element, the inner packaging body and the metal terminal are joined, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The electricity storage device according to the tenth aspect of the fifth aspect of the present disclosure is an electricity storage device according to any one of the first to sixth aspects, further comprising a metal terminal electrically connected to the electricity storage device element, the inner packaging body and the outer packaging body are joined to the metal terminal, and the entire inner packaging body is covered by the outer packaging body.

According to the first aspect of the present disclosure, a packaging film for an electricity storage device having a predetermined CO ₂ permeability can be provided. The packaging film for an electricity storage device according to the first aspect of the present disclosure can be suitably used as a packaging film for directly packaging an electricity storage device element. For example, in an electricity storage device in which an electricity storage device element is housed in a double-structured packaging body having an inner packaging body and an outer packaging body, the packaging film for an electricity storage device according to the first aspect of the present disclosure can be suitably used to form the inner packaging body. For example, the packaging film for an electricity storage device according to the first aspect of the present disclosure is used as the inner packaging body, and before being housed in the outer packaging body, the electricity storage device element is sealed in the inner packaging body, and an initial charge/discharge process and an aging process are performed, so that gas (especially CO ₂ ) generated from the electricity storage device element can be suitably released to the outside during these processes. Therefore, it is no longer necessary to provide a space for retaining gas inside the temporarily sealed packaging film for the electricity storage device, as is the case when using an exterior material for the electricity storage device having a conventional barrier layer, and it is no longer necessary to use a packaging film for the electricity storage device that is larger than the size required for the final product electricity storage device (for example, more than twice the size required to seal the electricity storage device elements) in order to remove the space containing the gas and release the gas to the outside.

Furthermore, according to the first aspect of the present disclosure, it is also possible to provide an electricity storage device using the packaging film for the electricity storage device.

According to the second aspect of the present disclosure, a packaging film for an electricity storage device can be provided that has adhesiveness to metal and does not have a metal layer formed from metal. The packaging film for an electricity storage device according to the second aspect of the present disclosure has adhesiveness to metal, and therefore can be adhered to, for example, a metal terminal. Specifically, the electricity storage device element can be sealed in a state in which the metal terminal is sandwiched between the heat-sealable resin layer. Furthermore, since the packaging film does not have a metal layer formed from metal, the packaging film for an electricity storage device can be made lighter and thinner. Furthermore, for example, according to the second aspect of the present disclosure, the packaging body that houses the electricity storage device can have a double structure of an inner packaging body and an outer packaging body, and the packaging film for an electricity storage device according to the present disclosure can be suitably used as the inner packaging body. According to the present disclosure, an electricity storage device using the packaging film for an electricity storage device can also be provided.

The method for manufacturing an electricity storage device and the electricity storage device according to the third aspect of the present disclosure allow for the efficient manufacture of an electricity storage device.

The manufacturing method for an electricity storage device and the electricity storage device according to the fourth aspect of the present disclosure make it easy to manufacture the electricity storage device.

The electricity storage device according to the fifth aspect of the present disclosure has high added-value functions.

1 is a schematic diagram showing an example of a cross-sectional structure of a packaging film for an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of a packaging film for an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of a packaging film for an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of a packaging film for an electricity storage device according to the present disclosure. 3 is a schematic diagram for illustrating a method of housing an electricity storage device element in a package formed from the electricity storage device packaging film of the present disclosure. FIG. 1 is a schematic diagram showing an example of a cross-sectional structure of an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of an electricity storage device according to the present disclosure. 1A to 1C are plan views of electric storage devices according to embodiments A1, B1 and C1 of the first and second aspects, and according to the third, fourth and fifth aspects. 9A to 9C are cross-sectional views taken along line D2-D2 of the first and second embodiments A1 and B1, the third embodiment, and the fourth embodiment of FIG. 8. FIG. 9 is a flowchart showing an example of a method for manufacturing an electricity storage device for the first and second embodiments A1 and B1, the third embodiment, and the fourth embodiment of FIG. 8 . This is a diagram relating to the inner wrapping step of FIG. 10, and is the same for the embodiment C1 of the first and second aspects, the third aspect, the fourth aspect and the fifth aspect. This is a diagram relating to the first inner sealing step of FIG. 10, and is similar to embodiment C1 of the first and second aspects, the third aspect, the fourth aspect and the fifth aspect. 10 , and is the same for the first and second aspects of embodiment C1, the third aspect, the fourth aspect and the fifth aspect. 10 is a flowchart showing an example of a method for manufacturing an electricity storage device according to embodiments A2 and B2 of the first and second aspects, the third and fourth aspects. This is a diagram relating to the inner wrapping step of Figure 14, and is the same for embodiment C2 of the first and second aspects, the third aspect, the fourth aspect and the fifth aspect. This is a diagram relating to the first inner sealing step of FIG. 14, and is similar to embodiment C2 of the first and second aspects, the third aspect, the fourth aspect and the fifth aspect. This is a diagram relating to the second inner sealing step of FIG. 14, and is the same for embodiment C2 of the first and second aspects, the third aspect, the fourth aspect and the fifth aspect. 15 is a diagram relating to the inner sealing step of FIG. 14, and is similar to embodiment C2 of the first and second aspects, the third, fourth and fifth aspects. 10 is a cross-sectional view of a terminal seal portion of an electricity storage device according to embodiments A2 and B2 of the first and second aspects, a third aspect, and a fourth aspect. FIG. 11 is a cross-sectional view of a terminal seal portion of an electricity storage device according to embodiments A3 and B3 of the first and second aspects, a third aspect, and a fourth aspect. FIG. 11 is a cross-sectional view of a terminal seal portion of an electricity storage device according to embodiments A3 and B3 of the first and second aspects, a third aspect, and a fourth aspect. FIG. 9 is a cross-sectional view taken along line D2-D2 of the embodiment C1 of the first and second aspects and the fifth aspect of FIG. 8. FIG. 9 is a flowchart showing an example of a method for manufacturing an electricity storage device according to embodiment C1 of the first and second aspects and the fifth aspect of FIG. 8 . 13 is a flowchart showing an example of a method for manufacturing an electricity storage device according to embodiment C2 of the first and second aspects, and a fifth aspect. 11 is a cross-sectional view of a terminal seal portion of an electric storage device according to embodiment C2 of the first and second aspects, and a fifth aspect. FIG. 11 is a cross-sectional view of a terminal seal portion of an electric storage device according to embodiment C3 of the first and second aspects, and a fifth aspect. FIG. 11 is a cross-sectional view of a terminal seal portion of an electric storage device according to embodiment C3 of the first and second aspects, and a fifth aspect. FIG.

A packaging film for an electricity storage device according to a first aspect of the present disclosure is a packaging film for an electricity storage device including at least a heat-sealable resin layer, and is characterized in that the _CO2 permeation amount in an environment at a temperature of 30°C is 100 cc·100 μm/ ^m2 /24 hr/atm or more.

The packaging film for an electricity storage device according to the second aspect of the present disclosure is a packaging film for an electricity storage device that includes at least a heat-sealable resin layer, has adhesion to metal, and does not have a metal layer formed from metal.

The packaging film for the power storage device of the present disclosure will be described in detail below. In this disclosure, the numerical range indicated by "-" means "greater than or equal to" or "less than or equal to". For example, the expression "2-15 mm" means 2 mm or more and 15 mm or less. In the numerical ranges described in stages in this disclosure, the upper limit or lower limit value described in a certain numerical range may be replaced with the upper limit or lower limit value of another numerical range described in stages. In addition, the upper limit and upper limit value, the upper limit and lower limit value, or the lower limit and lower limit value described separately may be combined to form a numerical range. In addition, in the numerical ranges described in this disclosure, the upper limit or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

In addition, in this disclosure, a shielding layer means a layer that blocks light transmission, and when the packaging film for an electricity storage device of the present disclosure has a shielding layer, the shielding layer makes it difficult to see the contents of the electricity storage device (e.g., electricity storage device elements). In addition, a metal layer means a layer formed from a metal, and examples of such layers include metal foil and metal plate, with the thickness of the metal foil being, for example, about 10 to 200 μm, and the thickness of the metal plate being, for example, about 200 μm to several mm.

In the explanation of this disclosure, matters specific to each of the first to fifth aspects of this disclosure will be clearly indicated as to which aspect the explanation relates to, and matters common to each aspect will be comprehensively explained as matters related to this disclosure without any particular indication. First, the contents common to the entire disclosure and the contents related to the first and second aspects of this disclosure will be explained, followed by the contents related to the third to fifth aspects.

1. Laminated Structure and Physical Properties of the Packaging Film for Electricity Storage Device The packaging film 10 for an electricity storage device according to the present disclosure includes at least a heat-sealable resin layer 1, as shown in, for example, Figures 1 to 4. When assembling an electricity storage device using the packaging film 10 for an electricity storage device and an electricity storage device element, the heat-sealable resin layers 1 of the packaging film 10 for an electricity storage device are placed opposite each other, and the peripheral portions are heat-sealed to form a space in which the electricity storage device element is housed.

The packaging film 10 for the electricity storage device may be composed only of the heat-sealable resin layer 1, as shown in FIG. 1. When the packaging film 10 for the electricity storage device is composed only of the heat-sealable resin layer 1, it is preferable that at least one surface of the heat-sealable resin layer 1 has adhesive properties to metal.

The packaging film 10 for an electricity storage device according to the present disclosure is preferably composed of a laminate including at least a resin layer 2 and a heat-sealable resin layer 1, as shown in Figs. 2 to 4. In such a packaging film 10 for an electricity storage device, the resin layer 2 is on the outside, and the heat-sealable resin layer 1 is on the inside (the innermost layer). When the packaging film 10 for an electricity storage device is composed of a laminate including a resin layer 2 and the heat-sealable resin layer 1, it is preferable to impart adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1.

Furthermore, as shown in Figs. 3 and 4, the packaging film 10 for an electricity storage device according to the present disclosure is preferably composed of a laminate including at least a resin layer 2, a substrate 3, and the heat-sealable resin layer 1. In such a packaging film 10 for an electricity storage device, the resin layer 2 is on the outside, the heat-sealable resin layer 1 is on the inside (the innermost layer), and the substrate 3 is located between the resin layer 2 and the heat-sealable resin layer 1. Even when the packaging film 10 for an electricity storage device is composed of a laminate including a resin layer 2, a substrate 3, and a heat-sealable resin layer 1, it is preferable to impart adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1.

As shown in Figures 2 and 4, adhesive layers 4 and 5 can be provided between the resin layer 2 and the substrate 3 or the heat-sealable resin layer 1, and between the heat-sealable resin layer 1 and the substrate 3 or the resin layer 2, respectively.

The packaging film 10 for an electricity storage device according to the first aspect of the present disclosure has a _CO2 permeation rate in an environment at a temperature of 30°C of 100 cc·100 μm/ ^m2 /24 hr/atm or more, preferably about 200 cc·100 μm/ ^m2 /24 hr/atm or more, more preferably about 300 cc·100 μm/ ^m2 /24 hr/atm or more, and even more preferably about 500 cc·100 μm/ ^m2 /24 hr/atm or more. The _CO2 permeation amount of the packaging film 10 for an electricity storage device according to the first embodiment of the present disclosure is, for example, about 2000cc·100μm/ ^m2 /24hr/atm or less, preferably about 1000cc·100μm/ ^m2 /24hr/atm or less, and more preferably about 800cc·100μm/ ^m2 /24hr/atm or less, and preferred ranges include about 100 to 2000cc·100μm/ ^m2 /24hr/atm, about 100 to 1000cc·100μm/ ^m2 /24hr/atm, about 100 to 800cc·100μm/ ^m2 /24hr/atm, and about 200 to 2000cc·100μm/m2 ^. /24hr/atm, 200-1000cc・100μm/m ² /24hr/atm, 200-800cc・100μm/m ² /24hr/atm, 300-2000cc・100μm/m ² /24hr/atm approximately, 300-1000cc・100μm/m ² /24hr/atm approximately, 300-800cc・100μm/m ² /24hr/atm approximately, 500-2000cc・100μm/m ² /24hr/atm or so, 500-1000cc/100μm/m ² /24hr/atm or so, 500-800cc/100μm/ ^m2 The _CO2 permeation amount of the packaging film for an electricity storage device is as follows:

<Measurement of _CO2 permeation amount>
In accordance with JIS K7126-1 (Plastics - Films and sheets - Gas permeability test method - Part 1: Differential pressure method), the amount of _CO2 that has permeated through a φ60 mm piece of the packaging film 10 for electricity storage devices in an atmosphere at 30°C is quantitatively analyzed by gas chromatography to measure the amount of CO2 permeated.

When imparting shielding properties to the packaging film 10 for an electricity storage device of the present disclosure, at least one layer included in the packaging film 10 for an electricity storage device may be a shielding layer S having shielding properties. For example, FIG. 4 illustrates a configuration in which the adhesive layer 4 that bonds between the resin layer 2 and the substrate 3 is the shielding layer S. In the present disclosure, any layer included in the packaging film 10 for an electricity storage device may be the shielding layer S.

Although not shown in the figure, a surface coating layer or the like may be further provided on the outside of the resin layer 2 (the side opposite to the heat-sealable resin layer 1) as necessary.

The thickness of the laminate constituting the packaging film 10 for electric storage devices is not particularly limited, but from the viewpoint of cost reduction and energy density improvement, for example, it is 190 μm or less, preferably about 180 μm or less, about 170 μm or less. From the viewpoint of maintaining the function of the packaging film for electric storage devices to protect the electric storage device elements, the thickness of the laminate constituting the packaging film 10 for electric storage devices is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more. Preferred ranges of the laminate constituting the packaging film 10 for electric storage devices include, for example, about 35 to 190 μm, about 35 to 180 μm, about 35 to 170 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 170 μm, about 60 to 190 μm, about 60 to 180 μm, and about 60 to 170 μm, with about 45 to 170 μm being particularly preferred.

In the packaging film 10 for the electric storage device, the ratio of the total thickness of the resin layer 2, adhesive layer 4, substrate 3, adhesive layer 5, and heat-sealable resin layer 1 to the thickness (total thickness) of the laminate constituting the packaging film 10 for the electric storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the packaging film 10 for the electric storage device of the present disclosure includes the resin layer 2, adhesive layer 4, substrate 3, adhesive layer 5, and heat-sealable resin layer 1, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging film 10 for the electric storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, even when the packaging film 10 for an electricity storage device of the present disclosure is a laminate including a resin layer 2, an adhesive layer 4, and a heat-sealable resin layer 1, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging film 10 for an electricity storage device can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

The laminate constituting the packaging film 10 for the electric storage device of the present disclosure can have a total light transmittance measured in accordance with the provisions of JIS K7361-1:1997 of, for example, 20% or less, 15% or less, 10% or less, 8% or less, etc. The laminate constituting the packaging film 10 for the electric storage device of the present disclosure can also have a total light transmittance measured in accordance with the provisions of JIS K7361-1:1997 of, for example, 80% or more, 85% or more, 90% or more, etc. The lower the total light transmittance, the higher the shielding property of the packaging film 10 for the electric storage device. On the other hand, the higher the total light transmittance, the higher the light transmittance of the packaging film 10 for the electric storage device. The lower limit of the total light transmittance is 0%, and the upper limit is 100%. The total light transmittance of the packaging film for power storage devices is measured in accordance with the measurement method specified in JIS K7361-1:1997 using a commercially available spectrophotometer (for example, JASCO's UV-Vis-Near-Infrared Spectrophotometer V-670) in the visible light region (400-700 nm), and the average value is taken as the total light transmittance. The measurement conditions are as follows: a halogen lamp is used as the light source, UV/Vis bandwidth: 5.0 nm, scanning speed: 1000 nm/min, response: Medium, data acquisition interval: 1.0 nm.

The packaging film 10 for the electricity storage device can be black. When the packaging film 10 for the electricity storage device is black, the packaging film 10 for the electricity storage device has high shielding properties and is highly effective in preventing counterfeiting. In addition, during the manufacturing process of the electricity storage device, it becomes possible to grasp the position with a sensor with higher accuracy, and it becomes possible to transport the packaging film 10 for the electricity storage device and seal the electricity storage device elements more accurately. Furthermore, it is possible to unify the electricity storage device and other electrical equipment in black, giving the product a luxurious feel.

The packaging film 10 for an electricity storage device of the second aspect of the present disclosure has a _CO2 permeation amount in an environment of 30°C of preferably 100 cc·100 μm/ ^m2 /24 hr/atm or more, more preferably about 200 cc·100 μm/ ^m2 /24 hr/atm or more, even more preferably about 300 cc·100 μm/ ^m2 /24 hr/atm or more, and even more preferably about 500 cc·100 μm/ ^m2 /24 hr/atm or more. The _CO2 permeation amount of the packaging film 10 for an electricity storage device according to the second aspect of the present disclosure is, for example, about 2000cc·100μm/ ^m2 /24hr/atm or less, preferably about 1000cc·100μm/ ^m2 /24hr/atm or less, and more preferably about 800cc·100μm/ ^m2 /24hr/atm or less, and preferred ranges include about 100 to 2000cc·100μm/ ^m2 /24hr/atm, about 100 to 1000cc·100μm/ ^m2 /24hr/atm, about 100 to 800cc·100μm/ ^m2 /24hr/atm, and about 200 to 2000cc·100μm/m2 ^. /24hr/atm, 200-1000cc・100μm/m ² /24hr/atm, 200-800cc・100μm/m ² /24hr/atm, 300-2000cc・100μm/m ² /24hr/atm approximately, 300-1000cc・100μm/m ² /24hr/atm approximately, 300-800cc・100μm/m ² /24hr/atm approximately, 500-2000cc・100μm/m ² /24hr/atm or so, 500-1000cc/100μm/m ² /24hr/atm or so, 500-800cc/100μm/ ^m2 The _CO2 permeation amount of the packaging film for an electricity storage device is as follows:

<Measurement of _CO2 permeation amount>
In accordance with JIS K7126-1 (Plastics - Films and sheets - Gas permeability test method - Part 1: Differential pressure method), the amount of _CO2 that has permeated through a φ60 mm piece of the packaging film 10 for electricity storage devices in an atmosphere at 30°C is quantitatively analyzed by gas chromatography to measure the amount of CO2 permeated.

2. Layers forming the packaging film for electricity storage devices [Heat-sealable resin layer 1]
In the packaging film 10 for an electricity storage device of the present disclosure, the heat-sealable resin layer 1 corresponds to the innermost layer and is a layer (sealant layer) that functions to seal the electricity storage device elements by heat-sealing the heat-sealable resin layers to each other when the electricity storage device is assembled.

The packaging film 10 for a power storage device of the first embodiment of the present disclosure may or may not have adhesion to metal, but preferably has adhesion to metal. For example, when the packaging film 10 for a power storage device of the first embodiment is composed of only the heat-sealable resin layer 1, it is preferable that at least one surface of the heat-sealable resin layer 1 has adhesion to metal. When the packaging film 10 for a power storage device of the first embodiment is composed of a laminate including the resin layer 2 and the heat-sealable resin layer 1, it is preferable that at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1 is given adhesion to metal. Also, when the packaging film 10 for a power storage device of the first embodiment is composed of a laminate including the resin layer 2, the substrate 3, and the heat-sealable resin layer 1, it is sufficient to give adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1.

When providing a shielding layer S in the packaging film 10 for an electricity storage device according to the first aspect of the present disclosure, it is preferable that the heat-sealable resin layer 1 of the packaging film 10 for an electricity storage device is transparent and is laminated with a shielding layer S that is a layer separate from the heat-sealable resin layer 1, but the shielding layer S may be formed by blending the aforementioned colorant or the like with the heat-sealable resin layer 1.

In addition, when the packaging film 10 for an electricity storage device of the second embodiment of the present disclosure is composed only of the heat-sealable resin layer 1, at least one surface of the heat-sealable resin layer 1 has adhesion to metal. When the packaging film 10 for an electricity storage device of the second embodiment is composed of a laminate including the resin layer 2 and the heat-sealable resin layer 1, at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1 may be provided with adhesion to metal. In addition, when the packaging film 10 for an electricity storage device of the second embodiment is composed of a laminate including the resin layer 2, the substrate 3, and the heat-sealable resin layer 1, at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1 may be provided with adhesion to metal.

When providing a shielding layer S in the packaging film 10 for an electricity storage device of the second embodiment, it is preferable that the heat-sealable resin layer 1 is transparent and is laminated with a shielding layer S that is composed of a layer separate from the heat-sealable resin layer 1, but the shielding layer S may be formed by blending the above-mentioned coloring agent or the like with the heat-sealable resin layer 1.

The resin constituting the heat-sealable resin layer 1 of the first embodiment is not particularly limited as long as it is heat-sealable and the _CO2 permeation amount of the packaging film 10 for an electricity storage device is 100 cc·100 μm/ ^m2 /24 hr/atm or more, but a resin containing a polyolefin skeleton such as polyolefin or acid-modified polyolefin is preferred. Polyolefin is preferred not only because it has heat-sealability but also because it has a very high _CO2 permeation amount.

The resin constituting the heat-sealable resin layer 1 of the second embodiment is not particularly limited as long as it is heat-sealable, but resins containing a polyolefin skeleton, such as polyolefins and acid-modified polyolefins, are preferred.

The resin constituting the heat-sealable resin layer 1 can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, etc., to determine whether the resin constituting the heat-sealable resin layer 1 contains a polyolefin skeleton. In addition, when the resin constituting the heat-sealable resin layer 1 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wave number of about 1760 cm ^-1 and a wave number of about 1780 cm ^-1 . When the heat-sealable resin layer 1 is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected by infrared spectroscopy. However, if the degree of acid modification is low, the peak may be small and not detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. Among these, polypropylene is preferred. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more types.

The polyolefin may be a cyclic polyolefin. A cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of the cyclic monomer that is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkenes are preferred, and norbornene is more preferred.

The polyolefin may be an acid-modified polyolefin. An acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. Examples of the polyolefin to be acid-modified include the above-mentioned polyolefins, copolymers of the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, and polymers such as crosslinked polyolefins. Examples of the acid component used for acid modification include carboxylic acids or anhydrides such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

The acid-modified polyolefin may be an acid-modified cyclic polyolefin. An acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin by replacing it with an acid component, or by block-polymerizing or graft-polymerizing an acid component to a cyclic polyolefin. The cyclic polyolefin to be acid-modified is the same as described above. The acid component used for the acid modification is the same as the acid component used for the modification of the polyolefin described above.

Preferred acid-modified polyolefins include polyolefins modified with carboxylic acids or their anhydrides, polypropylenes modified with carboxylic acids or their anhydrides, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

The heat-sealable resin layer 1 may be formed of one type of resin alone, or may be formed of a blend polymer of two or more types of resin. Furthermore, the heat-sealable resin layer 1 may be formed of only one layer, or may be formed of two or more layers of the same or different resins.

When at least a portion of the inner surface of the packaging film 10 for an electricity storage device is to be bonded to a metal (e.g., a metal terminal), the inner surface of the heat-sealable resin layer 1 has adhesiveness to the metal. In order to impart metal adhesiveness to the inner surface of the heat-sealable resin layer 1, for example, it is preferable that the inner surface of the heat-sealable resin layer 1 is made of an acid-modified polyolefin (acid-modified polypropylene, acid-modified polyethylene, etc.). The non-acid-modified polyolefin described above does not have adhesiveness to metal, and is therefore not suitable as a resin for forming the inner surface of the heat-sealable resin layer 1 when metal adhesiveness is to be imparted to the inner surface of the heat-sealable resin layer 1.

The heat-sealable resin layer 1 may also contain a lubricant, etc., if necessary. When the heat-sealable resin layer 1 contains a lubricant, the formability of the packaging film for the electricity storage device can be improved. There are no particular limitations on the lubricant, and any known lubricant can be used. The lubricant may be used alone or in combination of two or more types.

The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of lubricants include those exemplified for the resin layer 2. The lubricant may be used alone or in combination of two or more types. By combining two or more types of lubricants, adhesion of the lubricant to the die when cold-forming the packaging film for the electricity storage device 10 with a die due to interactions between the lubricants, etc., can be reduced, and continuous productivity of the electricity storage device can be suitably improved. This also applies to the case where a lubricant is used in the resin layer 2 described below.

When a lubricant is present on the surface of the heat-sealable resin layer 1, the amount of the lubricant present is not particularly limited, but from the viewpoint of improving the formability of the packaging film for electricity storage devices, the amount is preferably about ¹⁰ to 50 mg/m2, and more preferably about 15 to 40 mg/ ^m2 .

The lubricant present on the surface of the heat-sealable resin layer 1 may be a lubricant exuded from the resin that constitutes the heat-sealable resin layer 1, or a lubricant applied to the surface of the heat-sealable resin layer 1.

The thickness of the heat-sealable resin layer 1 is not particularly limited as long as it functions to seal the electricity storage device elements by heat-sealing the heat-sealable resin layers together, but may be, for example, about 150 μm or less, preferably about 85 μm or less, more preferably about 15 to 85 μm, and even more preferably about 35 to 85 μm.

[Resin layer 2]
In the present disclosure, the resin layer 2 is a layer provided for the purpose of functioning as a base material of the packaging film for an electricity storage device, etc. When the packaging film for an electricity storage device 10 has the resin layer 2, the resin layer 2 is located on the outer layer side of the packaging film for an electricity storage device.

The material for forming the resin layer 2 of the first embodiment is not particularly limited as long as it has at least insulating properties and the _CO2 permeation amount of the packaging film 10 for a storage battery device is 100 cc·100 μm/ ^m2 /24 hr/atm or more. The resin layer 2 of the first embodiment can be formed using a resin, and the resin may contain an additive described later. When the shielding layer S is provided in the packaging film 10 for a storage battery device of the first embodiment, it is preferable that the resin layer 2 is transparent and is used by laminating it with a shielding layer S composed of a layer other than the resin layer 2, but the shielding layer S may be formed by blending a colorant described later or the like into the resin layer 2.

The material forming the resin layer 2 of the second embodiment is not particularly limited, as long as it is at least insulating. The resin layer 2 of the second embodiment can be formed using a resin, which may contain an additive described below. The resin layer 2 of the second embodiment is preferably transparent and laminated with a shielding layer S that is a layer separate from the resin layer 2, but the resin layer 2 may also be blended with a colorant, etc., described below, to form the shielding layer S.

In the present disclosure, the resin layer 2 may be, for example, a resin film formed from a resin, or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially stretched films and biaxially stretched films, and biaxially stretched films are preferred. Examples of stretching methods for forming biaxially stretched films include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying a resin include roll coating, gravure coating, and extrusion coating.

In the present disclosure, examples of the resin forming the resin layer 2 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. The resin forming the resin layer 2 may also be a copolymer of these resins or a modified version of the copolymer. It may also be a mixture of these resins.

In the present disclosure, the resin forming the resin layer 2 is preferably polyester, polyamide, or polyolefin.

Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters in which ethylene terephthalate is the main repeating unit. Specific examples include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate/isophthalate)), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate), and polyethylene (terephthalate/decane dicarboxylate). These polyesters may be used alone or in combination of two or more.

Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) that contain structural units derived from terephthalic acid and/or isophthalic acid, and aromatic polyamides such as polyamide MXD6 (polymetaxylylene adipamide); alicyclic polyamides such as polyamide PACM6 (polybis(4-aminocyclohexyl)methane adipamide); polyamides copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers that are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and polyamides such as these copolymers. These polyamides may be used alone or in combination of two or more.

As the polyolefin, a resin containing a polyolefin skeleton, such as polyolefin or acid-modified polyolefin, is preferred. Polyolefin is preferred from the viewpoint of imparting heat fusion properties to the outer surface of the resin layer 2. Specific examples of polyolefin include the same polyolefins as those exemplified for the heat fusion resin layer 1 described above.

In the present disclosure, the resin layer 2 preferably includes at least one of a polyester film, a polyamide film, a polyolefin film, and an acid-modified polyolefin film, and preferably includes at least one of a stretched polyester film, a stretched polyamide film, a stretched polyolefin film, and a stretched acid-modified polyolefin film, and more preferably includes at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, a stretched polypropylene film, and a stretched acid-modified polypropylene film, and more preferably includes at least one of a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, a biaxially stretched nylon film, a biaxially stretched polypropylene film, and a biaxially stretched acid-modified polypropylene film.

In the present disclosure, when at least a part of the outer surface of the packaging film 10 for a storage device is adhered to a metal or the like, the resin layer 2 is the outermost layer, and the outer surface of the resin layer 2 has adhesiveness to the metal. In order to impart metal adhesiveness to the outer surface of the resin layer 2, for example, it is preferable that the outer surface of the resin layer 2 is composed of an acid-modified polyolefin (acid-modified polypropylene, acid-modified polyethylene, etc.). As described for the heat-sealable resin layer 4, the above-mentioned non-acid-modified polyolefin does not have adhesiveness to metal, and therefore is not suitable as a resin constituting the outer surface of the resin layer 2 when metal adhesiveness is imparted to the outer surface of the resin layer 2. Note that, as described above, when adhesiveness to metal is imparted to the outer surface of the base layer 1, the packaging film 10 for a storage device can be used as an inner packaging body, and the outer surface of the packaging film 10 for a storage device can be suitably adhered to an outer packaging body composed of a metal (e.g., metal foil, metal can, etc.).

In the present disclosure, the resin layer 2 may be a single layer, or may be composed of two or more layers. When the resin layer 2 is composed of two or more layers, the resin layer 2 may be a laminate in which a resin film is laminated with an adhesive or an adhesion promoter, or may be a laminate of resin films in which resins are co-extruded to form two or more layers. In addition, a laminate of resin films in which resins are co-extruded to form two or more layers may be used as the resin layer 2 without being stretched, or may be uniaxially or biaxially stretched to form the resin layer 2.

In the resin layer 2 of the present disclosure, specific examples of a laminate of two or more resin films include a laminate of a polyester film and a nylon film, a laminate of two or more nylon films, and a laminate of two or more polyester films. Preferably, a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, and a laminate of two or more stretched polyester films are preferred. For example, when the resin layer 2 is a laminate of two resin films, a laminate of a polyester resin film and a polyester resin film, a laminate of a polyamide resin film and a polyamide resin film, or a laminate of a polyester resin film and a polyamide resin film is preferred, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferred. In addition, when the resin layer 2 is a laminate of two or more resin films, it is preferred that the polyester resin film is located in the outermost layer of the resin layer 2, because the polyester resin is less likely to discolor when, for example, an electrolyte is attached to the surface.

In addition, from the viewpoint of imparting thermal fusion to the outer surface of the resin layer 2 of the present disclosure, specific examples of laminates of two or more resin films are preferably a laminate of polyolefin and polyester, a laminate of polyolefin and polyolefin, and a laminate of polyolefin and polyamide. For example, in the case of a laminate of polyolefin and polyester, a laminate of polypropylene film and polyethylene terephthalate film, a laminate of polypropylene film and polyethylene naphthalate film, a laminate of polypropylene film and polybutylene terephthalate film, a laminate of acid-modified polypropylene film and polyethylene terephthalate film, a laminate of acid-modified polypropylene film and polyethylene naphthalate film, and a laminate of acid-modified polypropylene film and polybutylene terephthalate film are preferred. In addition, for example, in the case of a laminate of polyolefin and polyolefin, a laminate of polypropylene and polypropylene, a laminate of acid-modified polypropylene and acid-modified polypropylene, and a laminate of acid-modified polypropylene and polypropylene are preferred. In the case of a laminate of polyolefin and polyamide, a laminate of polypropylene and nylon, and a laminate of acid-modified polypropylene and nylon are preferred.

In the present disclosure, when the resin layer 2 is a laminate of two or more layers of resin films, the two or more layers of resin films may be laminated via an adhesive or an adhesion promoter. Preferred adhesives and adhesion promoters include those similar to those exemplified in the adhesive layers 4 and 5 described below. The method for laminating two or more layers of resin films is not particularly limited, and known methods can be adopted, such as dry lamination, sandwich lamination, extrusion lamination, and thermal lamination, and preferably dry lamination. When laminating by the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive is, for example, about 2 to 5 μm. An anchor coat layer may also be formed on the resin film and laminated. The anchor coat layer may be the same as the adhesive exemplified in the adhesive layers 4 and 5 described below. In this case, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm. The anchor coat layer can be used as the adhesive layers 4 and 5.

In the present disclosure, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present on at least one of the surface and interior of the resin layer 2. Only one type of additive may be used, or two or more types may be mixed together.

In the present disclosure, from the viewpoint of improving the formability of the packaging film for the power storage device, it is preferable that a lubricant is present on the surface of the resin layer 2. The lubricant is not particularly limited, but is preferably an amide-based lubricant. Specific examples of amide-based lubricants include, for example, saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, and hydroxystearic acid amides. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of substituted amides include N-oleyl palmitic acid amides, N-stearyl stearic acid amides, N-stearyl oleic acid amides, N-oleyl stearic acid amides, and N-stearyl erucic acid amides. Specific examples of methylol amides include methylol stearic acid amides. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide. The lubricant may be used alone or in combination of two or more types.

In the present disclosure, when a lubricant is present on the surface of the resin layer 2, the amount thereof is not particularly limited, but is preferably about 3 mg/m2 or ^more , more preferably about 4 to 15 mg/ ^m2 , and even more preferably ^about 5 to 14 mg/m2.

In the present disclosure, the lubricant present on the surface of the resin layer 2 may be a lubricant that is exuded from the resin that constitutes the resin layer 2, or a lubricant that is applied to the surface of the resin layer 2.

In the present disclosure, the thickness of the resin layer 2 is not particularly limited, but may be, for example, about 3 to 50 μm, and preferably about 10 to 35 μm. When the resin layer 2 is a laminate of two or more resin films, the thickness of each of the resin films constituting each layer is preferably about 2 to 25 μm.

[Substrate 3]
In the packaging film 10 for an electricity storage device according to the present disclosure, the substrate 3 is a layer that functions as a support. When the packaging film 10 for an electricity storage device includes a resin layer 2, a substrate 3, and a heat-sealable resin layer 1, the resin layer 2 is on the outside, the heat-sealable resin layer 1 is on the inside (the innermost layer), and the substrate 3 is located between the resin layer 2 and the heat-sealable resin layer 1.

In the packaging film 10 for the electricity storage device disclosed herein, a colorant or the like can be blended into the substrate 3 to form a shielding layer S.

The material forming the substrate 3 of the present disclosure is not particularly limited. Examples of materials forming the substrate 3 include polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicone resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures and copolymers thereof, among which polyolefin resins are particularly preferred. In other words, the material forming the substrate 3 is preferably a resin containing a polyolefin skeleton, such as polyolefin or acid-modified polyolefin. The inclusion of a polyolefin skeleton in the resin constituting the substrate 3 can be analyzed, for example, by infrared spectroscopy, gas chromatography mass spectrometry, or the like.

Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymer polyesters whose repeating units are mainly ethylene terephthalate, and copolymer polyesters whose repeating units are mainly butylene terephthalate. Specific examples of copolymer polyesters whose repeating units are mainly ethylene terephthalate include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate/isophthalate)), polyethylene (terephthalate/isophthalate), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate), and polyethylene (terephthalate/decane dicarboxylate). Specific examples of copolymer polyesters containing butylene terephthalate as the main repeating unit include copolymer polyesters in which butylene terephthalate is the main repeating unit and is polymerized with butylene isophthalate (hereinafter abbreviated as polybutylene (terephthalate/isophthalate)), polybutylene (terephthalate/adipate), polybutylene (terephthalate/sebacate), polybutylene (terephthalate/decanedicarboxylate), polybutylene naphthalate, etc. These polyesters may be used alone or in combination of two or more.

Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is more preferred. In addition, since the substrate 3 has excellent electrolyte resistance, it is preferred that it contains homopolypropylene, and it is more preferred that it is formed of homopolypropylene, and it is even more preferred that it is an unstretched homopolypropylene film.

Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) that contain structural units derived from terephthalic acid and/or isophthalic acid, and aromatic polyamides such as polymetaxylylene adipamide (MXD6); alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); polyamides copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and copolymers of these. These polyamides may be used alone or in combination of two or more.

The substrate 3 of the present disclosure may also be formed from a nonwoven fabric made from the above-mentioned resin. When the substrate 3 is a nonwoven fabric, it is preferable that the substrate 3 is made from the above-mentioned polyolefin resin, polyamide resin, etc.

The substrate 3 of the present disclosure may be a single layer or multiple layers.

When the substrate 3 of the present disclosure is composed of a resin film, the surface of the substrate 3 may be subjected to a known adhesion enhancing means such as corona discharge treatment, ozone treatment, or plasma treatment, as necessary.

From the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the substrate 3 is preferably 80 μm or less, more preferably 60 μm or less, even more preferably about 50 μm or less, and even more preferably about 40 μm or less. The thickness of the substrate 3 is preferably about 5 μm or more, more preferably about 8 μm or more, and even more preferably about 10 μm or more. Preferred ranges for the thickness of the substrate 3 include about 5 to 80 μm, about 5 to 60 μm, about 5 to 50 μm, about 5 to 40 μm, about 8 to 80 μm, about 8 to 60 μm, about 8 to 50 μm, about 8 to 40 μm, about 10 to 80 μm, about 10 to 60 μm, about 10 to 50 μm, and about 10 to 40 μm.

[Adhesive layers 4, 5]
In the packaging film 10 for an electricity storage device of the present disclosure, the adhesive layers 4 and 5 are layers that are provided as necessary between the resin layer 2 and the substrate 3 or the heat-sealable resin layer 1, and between the heat-sealable resin layer 1 and the substrate 3 or the resin layer 2, respectively, for the purpose of increasing adhesion therebetween. The adhesive layer 4 bonds the resin layer 2 to the substrate 3 or the heat-sealable resin layer 1. The adhesive layer 5 bonds the heat-sealable resin layer 1 to the resin layer 2 or the substrate 3. The above-mentioned anchor coat layer can also be used as the adhesive layers 4 and 5.

In the packaging film 10 for the electric storage device, a coloring agent or the like can be blended into the adhesive layers 4 and 5 to form the shielding layer S. For example, if a coloring agent is blended into the adhesive forming the adhesive layer 4 and the shielding layer is formed by one coating, there is no need to provide a separate shielding layer in any location other than the adhesive layer 4. In this way, the number of steps can be reduced, production efficiency can be improved, and the risk of foreign matter contamination can be reduced compared to, for example, a case in which a separate coloring layer is provided as a shielding layer. In addition, if a coloring layer is provided between the resin layer 2 and the adhesive layer 4, there is a risk that the interfacial strength between the resin layer 2 and the coloring layer, and between the coloring layer and the adhesive layer 4, may decrease. Therefore, from the viewpoint of long-term use, it is preferable to blend a coloring agent into the adhesive layer 4.

The adhesive layers 4, 5 are formed from an adhesive or adhesion promoter that can adhere to the resin layer 2 or the heat-fusible resin layer 1. The adhesive used to form the adhesive layers 4, 5 is not limited, but may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, etc. Also, it may be a two-component curing adhesive (two-component adhesive), a one-component curing adhesive (one-component adhesive), or a resin that does not involve a curing reaction. Also, the adhesive layers 4, 5 may be a single layer or multiple layers.

Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymer polyamides; polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, polyurethane adhesives are preferred. In addition, the adhesive strength of these adhesive resins can be increased by using an appropriate curing agent in combination. The curing agent is selected from polyisocyanates, multifunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, and the like, depending on the functional groups of the adhesive components.

Examples of polyurethane adhesives include polyurethane adhesives containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. Preferably, a two-part curing polyurethane adhesive is used in which a polyol such as polyester polyol, polyether polyol, or acrylic polyol is used as the first agent, and an aromatic or aliphatic polyisocyanate is used as the second agent. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance, and an isocyanate compound. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance, and a polyol compound. Examples of polyurethane adhesives include polyurethane adhesives in which a polyurethane compound in which a polyol compound has been reacted with an isocyanate compound in advance is cured by reacting it with moisture in the air or the like. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group on the side chain in addition to the hydroxyl group at the end of the repeating unit. The second agent may be an aliphatic, alicyclic, aromatic, or araliphatic isocyanate compound. Examples of the isocyanate compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). Examples of the polyisocyanate compound include polyfunctional isocyanate modified compounds of one or more of these diisocyanates. In addition, a polymer (e.g., a trimer) may be used as the polyisocyanate compound. Examples of such polymers include adducts, biurets, and nurates. The adhesive layers 4 and 5 are made of polyurethane adhesive, which gives the packaging film for the electricity storage device excellent electrolyte resistance, and prevents the resin layer 2 from peeling off even if electrolyte adheres to the side surface.

The adhesion promoter used in forming the adhesive layers 4 and 5 is not limited. As the adhesion promoter, for example, well-known adhesion promoters such as isocyanate-based, polyethyleneimine-based, polyester-based, polyurethane-based, and polybutadiene-based adhesion promoters can be used. However, experimental results showed that those made of an isocyanate component selected from triisocyanate monomer and polymeric MDI had excellent laminate strength and showed little decrease in laminate strength after immersion in an electrolyte. In particular, the best results were obtained when an adhesion promoter made of triphenylmethane-4,4',4''-triisocyanate, which is a triisocyanate monomer, or polymethylene polyphenyl polyisocyanate, which is a polymeric MDI (NCO content of about 30%, viscosity of 200 to 700 mPa·s), was used. Next, tris(p-isocyanatephenyl)thiophosphate, which is also a triisocyanate monomer, and a two-component curing type adhesion promoter with a polyethyleneimine system as the main agent and a polycarbodiimide as the crosslinking agent showed good results. The adhesive layer 4, 5 using the adhesion promoter can be formed by coating and drying using a well-known coating method such as a bar coating method, a roll coating method, or a gravure coating method, and the coating amount is 20 to 100 mg/m ² , preferably 40 to 60 mg/m ² , in the case of an adhesion promoter made of triisocyanate, 40 to 150 mg/m ² , preferably 60 to 100 mg/m ² , in the case of an adhesion promoter made of polymeric MDI, and 5 to 50 mg/m ² , preferably 10 to 30 mg/m 2, in the case of a two-component curing type adhesion promoter with a polyethyleneimine system as the main agent and a polycarbodiimide as the ^crosslinking agent. The triisocyanate monomer is a monomer having three isocyanate groups in one molecule, and the polymeric MDI is a mixture of MDI and MDI oligomers formed by polymerization of MDI, and is represented by the following formula (1).

In addition, the adhesive layers 4 and 5 may contain other components as long as they do not impair adhesion, and may contain colorants, thermoplastic elastomers, tackifiers, fillers, etc. By including colorants in the adhesive layers 4 and 5, the packaging film for the electricity storage device can be colored. If the adhesive layers 4 and 5 are colored to an extent that the packaging film for the electricity storage device can be given shielding properties, the adhesive layers 4 and 5 can be used as shielding layers S. As colorants, known pigments, dyes, etc. can be used. In addition, only one type of colorant may be used, or two or more types may be mixed together.

There are no particular limitations on the type of pigment, so long as it does not impair the adhesive properties of the adhesive layers 4 and 5. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments, while examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, iron-based, and copper-based pigments, as well as finely powdered mica and fish scale foil.

Among colorants, for example, in order to give the appearance of the packaging film for the electricity storage device a black color, a black colorant is preferred, and among black colorants, carbon black is preferred. By using a black colorant to produce a black packaging film for the electricity storage device 10, the packaging film for the electricity storage device 10 has high shielding properties and high anti-counterfeiting effects. In addition, in the manufacturing process of the electricity storage device, it becomes possible to grasp the position with a sensor with higher accuracy, and it becomes possible to transport the packaging film for the electricity storage device 10 and seal the electricity storage device elements more accurately. Furthermore, it is possible to unify the electricity storage device and other electrical equipment in black to give the product a sense of luxury. Carbon black is a more preferred colorant in terms of its high shielding properties.

The average particle size of the pigment is not particularly limited, and may be, for example, about 0.05 to 5 μm, and preferably about 0.08 to 2 μm. The average particle size of carbon black may be within the range of 0.161 to 0.221 μm. The average particle size of the pigment is the median size measured with a laser diffraction/scattering type particle size distribution measuring device.

The content of the pigment in the adhesive layers 4 and 5 is not particularly limited as long as the packaging film for the electricity storage device is colored, and may be, for example, about 5 to 60% by mass, and preferably 10 to 40% by mass.

The thickness of the adhesive layers 4, 5 is not particularly limited as long as it can bond the resin layer 2 and the heat-sealable resin layer 1, but is, for example, about 1 μm or more, about 2 μm or more. The thickness of the adhesive layers 4, 5 is, for example, about 10 μm or less, about 5 μm or less. Preferred ranges for the thickness of the adhesive layers 4, 5 include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[Colored layer C]
In the present disclosure, although not shown, the colored layer C is a layer provided between the resin layer 2 and the heat-sealable resin layer 1, and on the outside of the resin layer 2, as necessary. When the adhesive layers 4 and 5 are provided, the colored layer C may be provided between the resin layer 2 and the adhesive layers 4 and 5. By providing the colored layer C, the packaging film for the electric storage device can be colored. If the colored layer C is colored to an extent that the packaging film for the electric storage device can be given shielding properties, the colored layer C can be the shielding layer S. In the packaging film for the electric storage device 10, it is preferable that the colored layer C is the shielding layer S. The colored layer C between the resin layer 2 and the heat-sealable resin layer 1 may be referred to as the inner colored layer, and the colored layer C on the outside of the resin layer 2 may be referred to as the outer colored layer. It is preferable that the colored layer C is provided on at least one surface of the resin layer 2 (i.e., the resin layer 2 and the colored layer C are in contact with each other).

In the present disclosure, the colored layer C can be formed, for example, by applying an ink containing a colorant to the surface of the resin layer 2. As the colorant, known pigments, dyes, and the like can be used. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

In this disclosure, specific examples of the colorant contained in colored layer C are the same as those exemplified in the section [Adhesive layers 4, 5].

In the present disclosure, the thickness of the colored layer C is not particularly limited as long as the packaging film 10 for electricity storage devices is colored, but is, for example, about 1 μm or more, about 2 μm or more. The thickness of the colored layer C is, for example, about 10 μm or less, about 5 μm or less. Preferred ranges for the thickness of the colored layer C include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[Surface coating layer]
The packaging film for an electricity storage device according to the present disclosure may, if necessary, have a surface coating layer (not shown) on the resin layer 2 (the side of the resin layer 2 opposite to the heat-sealable resin layer 1) for the purpose of improving at least one of design, electrolyte resistance, scratch resistance, formability, etc. The surface coating layer is a layer located on the outermost layer side of the packaging film for an electricity storage device when an electricity storage device is assembled using the packaging film for an electricity storage device. The surface coating layer may be blended with the above-mentioned colorant or the like to form a shielding layer S.

The surface coating layer may be, for example, a resin such as polyvinylidene chloride, polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, or phenol resin, or a modified product of these resins. It may also be a copolymer of these resins or a modified product of the copolymer. Furthermore, it may be a mixture of these resins. The resin is preferably a curable resin. In other words, the surface coating layer is preferably composed of a cured product of a resin composition containing a curable resin.

When the resin forming the surface coating layer is a curable resin, the resin may be either a one-component curable type or a two-component curable type, but is preferably a two-component curable type. Examples of two-component curable resins include two-component curable polyurethane, two-component curable polyester, and two-component curable epoxy resin. Among these, two-component curable polyurethane is preferred.

Examples of two-component curing polyurethane include polyurethanes containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. Preferably, two-component curing polyurethanes are made of a polyol such as polyester polyol, polyether polyol, and acrylic polyol as the first agent, and an aromatic or aliphatic polyisocyanate as the second agent. Examples of polyurethanes include polyurethane compounds in which a polyol compound and an isocyanate compound have been reacted in advance, and polyurethanes containing an isocyanate compound. Examples of polyurethanes include polyurethane compounds in which a polyol compound and an isocyanate compound have been reacted in advance, and polyurethanes containing a polyol compound. Examples of polyurethanes include polyurethanes in which a polyurethane compound in which a polyol compound and an isocyanate compound have been reacted in advance is cured by reacting it with moisture in the air or the like. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group on the side chain in addition to the hydroxyl group at the end of the repeating unit. As the second agent, aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds are included. Examples of isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). In addition, examples of the isocyanate compounds include polyfunctional isocyanate modified products of one or more of these diisocyanates. In addition, a polymer (e.g., a trimer) can also be used as the polyisocyanate compound. Examples of such polymers include adducts, biurets, and nurates. In addition, an aliphatic isocyanate compound refers to an isocyanate that has an aliphatic group and no aromatic ring, an alicyclic isocyanate compound refers to an isocyanate that has an alicyclic hydrocarbon group, and an aromatic isocyanate compound refers to an isocyanate that has an aromatic ring. The surface coating layer is formed from polyurethane, which gives the packaging film for the electricity storage device excellent electrolyte resistance.

The surface coating layer may contain additives such as the above-mentioned lubricants, antiblocking agents, matting agents, flame retardants, antioxidants, tackifiers, and antistatic agents, at least on the surface and/or inside of the surface coating layer, as necessary, depending on the functionality to be provided to the surface of the surface coating layer and its surface. Examples of additives include fine particles with an average particle size of about 0.5 nm to 5 μm. The average particle size of the additive is the median size measured by a laser diffraction/scattering type particle size distribution measuring device.

The additives may be either inorganic or organic. There are also no particular limitations on the shape of the additives, and examples of such shapes include spherical, fibrous, plate-like, amorphous, and scaly.

Specific examples of additives include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high melting point nylon, acrylate resin, cross-linked acrylic, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, etc. The additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. In addition, the additives may be subjected to various surface treatments such as insulation treatment and high dispersibility treatment.

The method for forming the surface coating layer is not particularly limited, and examples include a method of applying a resin that forms the surface coating layer. When an additive is added to the surface coating layer, a resin mixed with the additive may be applied.

The thickness of the surface coating layer is not particularly limited as long as it exhibits the above-mentioned functions as a surface coating layer, and may be, for example, about 0.5 to 10 μm, preferably about 1 to 5 μm.

3. Manufacturing method of packaging film for electric storage device The manufacturing method of the packaging film for electric storage device is not particularly limited as long as the packaging film for electric storage device of the present disclosure can be obtained. For example, when the packaging film for electric storage device of the first embodiment of the present disclosure has a resin layer 2 and a heat-sealable resin layer 1, the method includes a step of obtaining a laminate in which at least a resin layer and a heat-sealable resin layer are laminated from the outside, and the laminate has a CO ₂ permeation amount of 100 cc·100 μm/m ² /24 hr/atm or more in a temperature 30° C. environment. Also, for example, when the packaging film for electric storage device of the second embodiment of the present disclosure has a resin layer 2 and a heat-sealable resin layer 1, the method includes a step of obtaining a laminate in which at least a resin layer and a heat-sealable resin layer are laminated from the outside, and the laminate has adhesion to metal and does not have a metal layer formed by metal.

An example of a manufacturing method in which the packaging film for an electricity storage device of the present disclosure is configured as a laminate having a resin layer 2, an adhesive layer 4, a substrate 3, an adhesive layer 5, and a heat-sealable resin layer 1 in this order is as follows. First, the materials constituting each layer are prepared. Next, the resin layer 2 and the substrate 3 are laminated via the adhesive layer 4, and the substrate 3 and the heat-sealable resin layer 1 are laminated via the adhesive layer 5. Specifically, the resin layer 2 and the substrate 3 are laminated by a dry lamination method or the like using an adhesive that forms the adhesive layer 4, so that the resin layer 2, the adhesive layer 4, and the substrate 3 are laminated, and further, the substrate 3 and the heat-sealable resin layer 1 are laminated by a dry lamination method or the like using an adhesive that forms the adhesive layer 5, thereby manufacturing the packaging film for an electricity storage device 10. In addition, when the resin layer 2, the substrate 3, and the heat-sealable resin layer 1 are laminated without the adhesive layers 4 and 5, the packaging film 10 for the electric storage device can be manufactured by melt-extruding the resin constituting the resin layer 2 onto one side of the substrate 3, and melt-extruding the resin constituting the heat-sealable resin layer 1 onto the other side of the substrate 3. When a colored layer is provided, the colored layer is formed on the surface of the resin layer 2, and then laminated with the substrate 3 and the heat-sealable resin layer 1. When a surface coating layer is provided, it can be formed, for example, by applying the above-mentioned resin composition for forming the surface coating layer onto the surface of the resin layer 2 and curing it.

To strengthen the adhesive properties of the adhesive layers 4 and 5, the packaging film 10 for the electricity storage device may be subjected to a heat treatment.

The packaging film for an electricity storage device according to the present disclosure is used in a package for hermetically housing an electricity storage device element such as a positive electrode, a negative electrode, an electrolyte, etc. In other words, an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed by the packaging film for an electricity storage device according to the present disclosure to form an electricity storage device.

Specifically, an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte is covered with the packaging film for an electricity storage device of the present disclosure in such a manner that a flange portion (a region where the heat-sealable resin layers contact each other) can be formed around the periphery of the electricity storage device element with the metal terminals connected to each of the positive electrode and negative electrode protruding outward, and the heat-sealable resin layers of the flange portion are heat-sealed to provide an electricity storage device using the packaging film for an electricity storage device. When an electricity storage device element is housed in a package formed with the packaging film for an electricity storage device of the present disclosure, the package is formed so that the heat-sealable resin portion of the packaging film for an electricity storage device of the present disclosure faces inside (the surface in contact with the electricity storage device element). The heat-sealable resin layers of two packaging films for a power storage device may be overlapped with each other so as to face each other, and the peripheral portions of the overlapped packaging films for a power storage device may be heat-sealed to form a package. Alternatively, as shown in the example of FIG. 5, one packaging film for a power storage device may be folded back and overlapped, and the peripheral portions may be heat-sealed to form a package. When folding back and overlapping, as shown in the example of FIG. 5, the sides other than the folded side may be heat-sealed to form a package by sealing on three sides, or the film may be folded back to form a flange portion and sealed on all four sides. In addition, a recess for accommodating a power storage device element may be formed in the packaging film for a power storage device by deep drawing or bulging. As shown in the example of FIG. 5, one packaging film for a power storage device may have a recess and the other packaging film for a power storage device may not have a recess, or the other packaging film for a power storage device may also have a recess.

7, the packaging film 10 for the electric storage device of the present disclosure can be suitably used as the inner packaging body 10a of the electric storage device 30 in which the electric storage device element 32 is housed in a container having a double structure of the inner packaging body 10a and the outer packaging body 20. That is, the electric storage device element 32 having at least a positive electrode, a negative electrode, and an electrolyte is housed in the inner packaging body 10a formed by the packaging film 10 for the electric storage device of the present disclosure, and the inner packaging body 10a is further housed in the outer packaging body 20, thereby obtaining the electric storage device 30 in which the electric storage device element is housed in a container having a double structure of the inner packaging body 10a and the outer packaging body 20. One or more members in which the electric storage device element 32 is housed in the inner packaging body 10a formed by the packaging film 10 for the electric storage device of the present disclosure can be prepared, and one or more members can be housed in the outer packaging body 20 to form the electric storage device 30. In addition, although each corner is depicted as a right angle in Figures 5 to 7, the angle of each corner or edge is not limited, and each corner or edge may be rounded.

In the electricity storage device 30 of FIG. 7, the metal terminals 31 connected to the positive and negative electrodes of the electricity storage device element 32 are protruding outward, and the flange portion (the area where the heat-sealable resin layers 1 contact each other, the peripheral portion 30a of the inner packaging body 10a) of the inner packaging body 10a formed by the packaging film 10 for the electricity storage device is formed around the periphery of the electricity storage device element 32. The heat-sealable resin layers 1 of the flange portion are heat-sealed and sealed together, so that the heat-sealable resin layer 1 is adhered to the metal terminal 10 while the electricity storage device element 32 is sealed with the inner packaging body 10a. When the inner surface of the heat-sealable resin layer 1 of the packaging film 10 for the electricity storage device of the present disclosure has adhesiveness to metal, it can be preferably used as a packaging film that directly packages the electricity storage device element 32 by adhering it to the metal terminal 31. In an electric storage device 30 in which an electric storage device element 32 is housed in a double-layered package including an inner package 10a and an outer package 20 as shown in FIG. 7, the packaging film 10 for an electric storage device of the present disclosure can be suitably used to form the inner package 10a. Since the metal terminal 31 and the heat-sealable resin layer of the packaging film are made of different materials, adhesion is generally likely to decrease at the interface between the metal terminal 31 and the heat-sealable resin layer. For this reason, an adhesive film is generally disposed between the metal terminal and the heat-sealable resin layer of the packaging film, but the packaging film 10 for an electric storage device of the present disclosure has adhesive properties to metal, so that the electric storage device element 32 can be sealed while adhering to the metal terminal 31 without using such an adhesive film.

There are no particular limitations on the outer packaging body 20, and it is possible to use a packaging film, a metal can, or the like, which is made of a film-like laminate in which a base layer, a metal layer, and a heat-sealable resin layer are laminated in that order.

The packaging film for the power storage device of the present disclosure can be suitably used for power storage devices such as batteries (including condensers, capacitors, etc.). The packaging film for the power storage device of the present disclosure may be used for either primary or secondary batteries, but is preferably used for secondary batteries. The type of secondary battery to which the packaging film for the power storage device of the present disclosure is applied is not particularly limited, and examples thereof include lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, lead-acid batteries, nickel-hydrogen batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, capacitors, etc. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for the packaging film for the power storage device of the present disclosure.

Furthermore, the packaging film for an electricity storage device according to the first aspect of the present disclosure (at least a packaging film for an electricity storage device having a heat-sealable resin layer, in which the _CO2 permeation amount in an environment at a temperature of 30°C is 100 cc·100 μm/ ^m2 /24 hr/atm or more) and the packaging film for an electricity storage device according to the second aspect of the present disclosure (at least a packaging film for an electricity storage device having a heat-sealable resin layer, in which the packaging film for an electricity storage device has adhesion to metal, and the packaging film for an electricity storage device does not have a metal layer formed by metal) can be suitably applied to an electricity storage device or a manufacturing method thereof according to embodiment A (embodiments A1 to A5 and their modifications), an electricity storage device or a manufacturing method thereof according to embodiment B (embodiments B1 to B5 and their modifications), and an electricity storage device or a manufacturing method thereof according to embodiment C (embodiments C1 to C5 and their modifications), respectively, which are shown below. The following describes in detail the embodiments A, B, and C of the first and second aspects.

<Embodiment A>
As described above, in the manufacturing process of the electric storage device, the electric storage device element is generally accommodated in the packaging film for the electric storage device, and then the periphery of the packaging film for the electric storage device is sealed to temporarily seal it. Then, the initial charge/discharge process and the aging process are performed. In these processes, it is known that gas such as _CO2 is generated from the electric storage device element, and in order to provide a space for holding the gas inside the temporarily sealed package (made of the packaging film for the electric storage device), and further to remove the space in which the gas is held and release the gas to the outside, the electric storage device is currently manufactured using a packaging film for the electric storage device that is larger than the size required for the electric storage device that will ultimately be the product (for example, more than twice the size required for sealing the electric storage device element). For this reason, the manufacturing process of the electric storage device is complicated.

The invention according to embodiment A aims to provide a method for easily manufacturing an electricity storage device, and an electricity storage device manufactured by this manufacturing method.

The manufacturing method of the electricity storage device according to the first aspect of the invention in embodiment A is a manufacturing method of the electricity storage device, the electricity storage device includes an electricity storage device element and an inner packaging body that houses the electricity storage device element, the inner packaging body is composed of a packaging film for electricity storage devices that has gas permeability, and includes an inner packaging step of wrapping the electricity storage device element with the packaging film for electricity storage devices, an inner sealing step that is performed after the inner packaging step and seals the packaging film for electricity storage devices so that the electricity storage device element is hermetically sealed by the packaging film for electricity storage devices, and a degassing step that is performed after the inner sealing step and releases gas generated from the electricity storage device element through the packaging film for electricity storage devices.

The method for manufacturing an electricity storage device according to the second aspect of the invention in embodiment A is the method for manufacturing an electricity storage device according to the first aspect, in which in the inner packaging step, the electricity storage device element is wrapped in the electricity storage device packaging film that is substantially the same size as the inner packaging body of the finished electricity storage device.

The electric storage device according to the third aspect of the invention of embodiment A comprises an electric storage device element, an inner packaging body that houses the electric storage device element, and an outer packaging body that houses the inner packaging body in which the electric storage device element is housed, and the inner packaging body is composed of a gas-permeable packaging film for electric storage devices.

The electric storage device according to the fourth aspect of the invention in embodiment A is the electric storage device according to the third aspect, further comprising a metal terminal electrically connected to the electric storage device element and a tab film disposed between the inner packaging body and the metal terminal, the outer packaging body is joined to the inner packaging body, the inner packaging body and the metal terminal are joined via the tab film, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The electric storage device according to the fifth aspect of the invention in embodiment A is the electric storage device according to the third aspect, further comprising a metal terminal electrically connected to the electric storage device element, and a tab film disposed between the inner packaging body and the outer packaging body and the metal terminal, the inner packaging body and the outer packaging body being joined to the metal terminal via the tab film, and the entire inner packaging body being covered by the outer packaging body.

The sixth aspect of the invention according to embodiment A is the third aspect of the energy storage device, further comprising a metal terminal electrically connected to the energy storage device element, the inner packaging body and the metal terminal are joined, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The seventh aspect of the invention according to embodiment A is an electricity storage device according to any one of the third to sixth aspects, and the packaging film for the electricity storage device further has transparency.

[Embodiment A1]
FIG. 8 shows a plan view of the power storage device 100 according to the present embodiment A1. FIG. 9 is a cross-sectional view taken along the line D2-D2 in FIG. 8. In FIG. 8, a portion that is not visible from the outside is partially shown by dotted lines for reference. Hereinafter, for convenience of explanation, unless otherwise specified, the up-down direction in FIG. 8 is referred to as the "front-rear direction", the left-right direction is referred to as the "left-right direction", and the up-down direction in FIG. 9 is referred to as the "up-down direction". However, the orientation of the power storage device 100 during use is not limited to this. In addition, in FIG. 8, the relative positional relationship between the inner wrapping body 210 and the outer wrapping body 220 is simplified for the sake of simplicity of the drawing.

The energy storage device 100 comprises a housing 110, an energy storage device element 120, a pair of metal terminals 130, and a pair of tab films 140. The housing 110 comprises an internal space S1 and a peripheral seal portion 150. The energy storage device element 120 is housed in the internal space S1 of the housing 110. One end of the metal terminal 130 is joined to the energy storage device element 120, and the other end protrudes outward from the peripheral seal portion 150 of the housing 110. A portion of the area between one end and the other end of the metal terminal 130 is fused to the peripheral seal portion 150 via the tab film 140.

The container 110 includes a container 110A. The container 110A includes an inner packaging body 210 and an outer packaging body 220. The inner packaging body 210 contains the power storage device element 120. The outer packaging body 220 contains the inner packaging body 210 in which the power storage device element 120 is contained. An internal space S1 is formed inside the inner packaging body 210. The inner packaging body 210 includes packaging films 211 and 212 for the power storage device. The outer packaging body 220 includes exterior films 221 and 222. In the outer peripheral portion of the container 110A in a plan view, the inner packaging body 210 and the outer packaging body 220 are heat-sealed and fused to each other, thereby forming a peripheral seal portion 150. The peripheral seal portion 150 forms an internal space S1 of the container 110A that is isolated from the external space in the inner packaging body 210. The peripheral seal portion 150 defines the periphery of the internal space S1 of the container 110A. The heat seal mode referred to here may be heat fusion from a heat source, ultrasonic fusion, or the like. In any case, the peripheral seal portion 150 refers to the portion where the inner wrapping body 210 and the outer wrapping body 220 are fused together to form an integrated unit.

The peripheral seal portion 150 includes a top seal portion 151, a pair of side seal portions 152, 153, and a bottom seal portion 154. The top seal portion 151 includes a portion that is sealed by sandwiching the metal terminal 130 and the tab film 140 (hereinafter referred to as "terminal seal portion 151A"), and extends in the front-rear direction. The pair of side seal portions 152, 153 extend in the left-right direction. The side seal portion 152 and the side seal portion 153 face each other across the internal space S1. The bottom seal portion 154 faces the top seal portion 151 across the internal space S1. The bottom seal portion 154 extends in the front-rear direction.

9, the terminal seal portion 151A of the top seal portion 151 is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. This makes it easy to form the top seal portion 151. Note that the portion of the top seal portion 151 other than the terminal seal portion 151A, in other words, the portion where only the pair of tab films 140 are sandwiched between the inner packaging body 210 and the outer packaging body 220, is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. Furthermore, the outer portion of the terminal seal portion 151A of the top seal portion 151 (the left portion with the step as the boundary in FIG. 9) is made up of, from the top, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, and the packaging film for the power storage device 212, which are laminated and integrated together. Therefore, there is a step between the outer portion of the terminal seal portion 151A where the exterior films 221, 222 are not present and the inner portion of the terminal seal portion 151A where the exterior films 221, 222 are present (the right portion with the step as the boundary in FIG. 9), but FIG. 8 shows an overview of the area of the peripheral seal portion 150, and does not show the step as the boundary.

The electricity storage device packaging films 211, 212 constituting the inner packaging body 210 have gas permeability from the viewpoint of easily manufacturing the electricity storage device 100. Below, preferred examples of the electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are described. In the following, when there is no particular distinction between the electricity storage device packaging films 211, 212, the electricity storage device packaging films 211, 212 may be collectively referred to as the electricity storage device packaging film 10.

The shape of the inner packaging body 210 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The inner packaging body 210 of this embodiment A1 has a shape as shown in FIG. 9, and is manufactured by heat sealing the packaging film for the power storage device 212 formed into a tray shape and the packaging film for the power storage device 211, which is also formed into a tray shape and overlapped on the packaging film for the power storage device 212, along the outer periphery in a plan view. The packaging film for the power storage device 212 includes a square ring-shaped flange portion 212A corresponding to the outer periphery in a plan view, and a molded portion 212B that is continuous with the inner edge of the flange portion 212A and bulges downward from there. Similarly, the electricity storage device packaging film 211 includes a rectangular ring-shaped flange portion 211A that corresponds to the outer periphery in a plan view, and a flange portion 211B that is continuous with the inner edge of the flange portion 211A and bulges upward from the flange portion 211A. The electricity storage device packaging films 211 and 212 are overlapped such that the respective molded portions 211B and 212B bulge in opposite directions. In this state, the flange portion 211A of the electricity storage device packaging film 211 and the flange portion 212A of the electricity storage device packaging film 212 are heat-sealed so as to be integrated, forming a part of the peripheral seal portion 150. Note that one of the electricity storage device packaging films 211 and 212 may be in the form of a sheet.

The exterior films 221, 222 constituting the outer packaging body 220 are, for example, made of a resin molded product or film. The resin molded product referred to here can be manufactured by injection molding, compressed air molding, vacuum molding, blow molding, or other methods, and in-mold molding may be used to impart design and functionality. The type of resin may be polyolefin, polyester, nylon, ABS, or other materials. The film referred to here is, for example, a resin film that can be manufactured by an inflation method or a T-die method, or a resin film laminated on a metal foil or metal plate. The film referred to here may or may not be stretched, and may be a single-layer film or a multilayer film. The multilayer film referred to here may be manufactured by a coating method, may be a film in which multiple films are bonded together with an adhesive, or may be manufactured by a multilayer extrusion method.

The exterior films 221, 222 can be configured in various ways, but in this embodiment A1, they are configured from a laminate film. The laminate film can be a laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated. The base layer functions as a base material for the exterior films 221, 222, and is typically a resin layer that forms the outer layer side of the outer packaging body 220 and has insulating properties. The barrier layer has a function of preventing at least moisture and the like from penetrating into the power storage device 100 in addition to improving the strength of the exterior films 221, 222, and is typically a metal layer made of aluminum alloy foil or the like. The heat-sealable resin layer is typically made of a heat-sealable resin such as polyolefin, and forms the innermost layer of the outer packaging body 220.

The shape of the outer packaging body 220 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The container 110A of this embodiment A1 has a shape as shown in FIG. 9, and is manufactured by heat-sealing an exterior film 222 formed into a tray shape and an exterior film 221 similarly formed into a tray shape and superimposed on the exterior film 222 along the outer periphery in a plan view. The exterior film 222 includes a square ring-shaped flange portion 222A corresponding to the outer periphery in a plan view, and a molded portion 222B that is continuous with the inner edge of the flange portion 222A and bulges downward therefrom. Similarly, the exterior film 221 includes a square ring-shaped flange portion 221A corresponding to the outer periphery in a plan view, and a flange portion 221B that is continuous with the inner edge of the flange portion 221A and bulges upward therefrom. The exterior films 221 and 222 are overlapped so that the respective molded portions 221B and 222B bulge in opposite directions. In this state, the flange portion 221A of the exterior film 221 and the flange portion 222A of the exterior film 222 are heat sealed to be integrated together, forming a part of the peripheral seal portion 150. Note that one of the exterior films 221 and 222 may be in the form of a sheet.

As shown in FIG. 9, in the terminal seal portion 151A, a portion of the flange portion 211A of the packaging film 211 for the power storage device is joined to one of the tab films 140. A portion of the flange portion 212A of the packaging film 212 for the power storage device is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the electricity storage device. The end 221X of the flange portion 221A is located closer to the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device.

The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the electricity storage device. The end 222X of the flange portion 222A is located closer to the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 222X of the flange portion 222A may be located in the same position as the end 212X of the packaging film 212 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device.

The power storage device element 120 has at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, a lithium ion battery (secondary battery) or a power storage member such as a capacitor.

The metal terminal 130 is a metal terminal used for inputting and outputting power to and from the power storage device element 120. The metal terminal 130 is arranged, for example, in the top seal portion 151 of the container 110A, with one terminal constituting a positive electrode side terminal and the other terminal constituting a negative electrode side terminal. One end in the left-right direction of each metal terminal 130 is electrically connected to an electrode (positive electrode or negative electrode) of the power storage device element 120 in the internal space S1 of the container 110A, and the other end protrudes outward from the peripheral seal portion 150. The above-mentioned form of the power storage device 100 is particularly preferable for use in electric vehicles such as electric vehicles and hybrid vehicles that use a large number of power storage devices 100 connected in series at high voltage. The mounting positions of the two metal terminals 130 that constitute the positive and negative electrode terminals are not particularly limited, and may be arranged, for example, in the side seal portions 152, 153 or bottom seal portion 154 of the peripheral seal portion 150.

The metal material constituting the metal terminal 130 is, for example, aluminum, nickel, copper, etc. When the power storage device element 120 is a lithium ion battery, the metal terminal 130 connected to the positive electrode is typically made of aluminum, etc., and the metal terminal 130 connected to the negative electrode is typically made of copper, nickel, etc.

The tab film 140 is a so-called adhesive film, and is configured to adhere to both the electricity storage device packaging films 211, 212 and the metal terminal 130. By using the tab film 140, the metal terminal 130 and the innermost layer (thermally adhesive resin layer) of the electricity storage device packaging films 211, 212 can be fixed together even if they are made of different materials. The tab film 140 is integrated by being fused and fixed to the metal terminal 130 in advance, and the electricity storage device packaging films 211, 212 are fused to the metal terminal 130 to which the tab film 140 is fixed.

[Method of manufacturing electricity storage device]
10 is a flowchart showing an example of a method for manufacturing the power storage device 100. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging process of step S11, as shown in FIG. 11, the formed electricity storage device packaging films 211, 212 are wrapped around the electricity storage device element 120. In the electricity storage device 100 of this embodiment A1, the electricity storage device packaging films 211, 212 are gas permeable, so there is no need to form a sub-chamber for temporarily storing the gas generated from the electricity storage device element 120 in the initial filling process described below. Therefore, in the inner packaging process, the electricity storage device element 120 is wrapped around the electricity storage device packaging films 211, 212 that are substantially the same size as the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the finished electricity storage device 100. This simplifies the manufacturing process of the electricity storage device 100. In addition, the amount of material used for the electricity storage device 100 can be reduced. "Substantially the same size" includes cases where the size is larger than the electricity storage device packaging films 211, 212 included in the inner packaging body 210 of the finished electricity storage device 100 to the extent that a sub-chamber cannot be formed. Note that the electricity storage device element 120 is connected to the metal terminal 130 in advance, and the tab film 140 is joined to the metal terminal 130.

The first inner sealing process in step S12 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 12, the portions of the periphery of the electricity storage device packaging films 211, 212 that correspond to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed. Completion of the first inner sealing process forms an opening 213 in the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed. After the first inner sealing process, the vacuum drying process in step S13 is carried out.

The electrolyte injection process in step S14 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 12).

The second inner sealing process of step S15 is performed after the electrolyte injection process. As shown in FIG. 16, in the second inner sealing process, the opening 213 is closed by sealing the portion of the periphery of the packaging films 211 and 212 for the electricity storage device where the side seal portion 153 is to be formed. According to the electricity storage device 100, since the packaging films 211 and 212 for the electricity storage device have transparency, it is easy to check whether the packaging films 211 and 212 for the electricity storage device are properly sealed after the first inner sealing process or the second inner sealing process is completed. Therefore, the electricity storage device 100 can be suitably manufactured. The state in which the packaging films 211 and 212 for the electricity storage device are not properly sealed includes, for example, the first state, the second state, or the third state. The first state is a state in which the packaging films 211 and 212 for the electricity storage device are sealed with a foreign object in between. The second state is a state in which a part that should be sealed is not sealed. The third state is a state in which a part that should not be sealed is sealed. After the second inner sealing process, the initial charge/discharge process of step S16 and the aging process of step S17 are carried out in order.

The degassing process in step S18 is carried out in parallel with the initial charge/discharge process and the aging process. In this embodiment A1, the packaging films 211 and 212 for the electricity storage device are gas permeable, so that gases such as carbon dioxide generated from the electricity storage device element 120 during the initial charge/discharge process and the aging process are discharged to the outside through the packaging films 211 and 212 for the electricity storage device. After the degassing process, the main charging process in step S19 is carried out.

The outer packaging process in step S20 is carried out after the main charging process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S21 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221 and 222 is sealed to form the periphery seal portion 150.

[Characteristics of the energy storage device]
In the electricity storage device 100 of the present embodiment A1, the electricity storage device packaging films 211, 212 are gas permeable, so there is no need to form an auxiliary chamber for temporarily storing gas generated from the electricity storage device element 120 in an initial filling step or the like described below. This makes it possible to simplify the manufacturing process for the electricity storage device 100. In addition, the amount of material used for the electricity storage device 100 can be reduced.

[Embodiment A2]
The electricity storage device 100 of embodiment A2 differs from embodiment A1 in that the electricity storage device packaging films 211, 212 are not transparent, but the other configurations are the same as those of embodiment A1. The electricity storage device 100 of embodiment A2 will be described below, focusing on the differences from embodiment A2.

[Method of manufacturing electricity storage device]
11 is a flowchart showing an example of a method for manufacturing the power storage device 100 according to embodiment A2. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging process of step S31, as shown in FIG. 12, the electricity storage device element 120 is wrapped in the formed electricity storage device packaging films 211, 212. In the electricity storage device 100 of this embodiment A2, an auxiliary chamber 214 is formed to temporarily store gas generated from the electricity storage device element 120 during the initial filling process, etc. For this reason, in the inner packaging process, the electricity storage device element 120 is wrapped in the electricity storage device packaging films 211, 212 that are larger than the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the completed electricity storage device 100. In the auxiliary chamber 214 of the electricity storage device packaging films 211, 212, a storage chamber 215 is formed to store more gas generated from the electricity storage device element 120.

The first inner sealing process of step S32 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 16, the portions of the periphery of the electricity storage device packaging films 211, 212 corresponding to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed so as to extend to the auxiliary chamber 214. Completion of the first inner sealing process forms an opening 213 in a portion 216 that faces the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed, across the auxiliary chamber 214. After the first inner sealing process, the vacuum drying process of step S33 is carried out.

The electrolyte injection process in step S34 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 16).

The second inner sealing step of step S35 is carried out after the electrolyte injection step. As shown in FIG. 17, in the second inner sealing step, the opening 213 is closed by sealing the portion 216 of the periphery of the packaging films 211, 212 for the electricity storage device, where the side seal portion 153 is to be formed, and the portion 216 facing the auxiliary chamber 214. After the second inner sealing step, the initial charge/discharge step of step S36 and the aging step of step S37 are carried out in sequence.

The degassing process in step S38 is carried out after the aging process. In the degassing process, gases such as carbon dioxide generated from the electricity storage device element 120 are temporarily stored in the auxiliary chamber 214 of the electricity storage device packaging films 211 and 212.

The auxiliary chamber removal process in step S39 is carried out after the degassing process. In the auxiliary chamber removal process, the auxiliary chamber 214 is removed by cutting the packaging films 211, 212 for the electricity storage device along the dashed line XA shown in Figure 17 so that the auxiliary chamber 214 is the same size as the inner packaging body 210 of the completed electricity storage device 100.

The inner sealing process of step S40 is carried out after the auxiliary chamber removal process. In the inner sealing process, as shown in FIG. 18, the portion of the periphery of the packaging films 211, 212 for the electricity storage device that corresponds to the side seal portion 153 is sealed. After the inner sealing process, the main charging process of step S41 is carried out.

The outer packaging process in step S42 is carried out after the main charging process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S43 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221 and 222 is sealed to form the periphery seal portion 150.

[Embodiment A3]
The power storage device 300 of the embodiment A3 is different from the embodiment A1 in that the configuration of the terminal seal portion 151A is different, and other configurations are the same as those of the embodiment A1. The following describes the power storage device 300 of the embodiment A3, focusing on the parts that differ from the embodiment A1.

Figure 19 is a cross-sectional view of a terminal seal portion 351A provided in the electricity storage device 300 of embodiment A3. In the terminal seal portion 351A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to one tab film 140. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to one of the tab films 140. The flange portion 222A of the exterior film 222 is joined to the other tab film 140. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the power storage device 300, the inner packaging body 210 is covered by the outer packaging body 220, so that intrusion of moisture and the like from the outside into the internal space S1 of the inner packaging body 210 is suppressed.

[Embodiment A4]
The power storage device 400 of embodiment A4 differs from embodiment A1 in that the configuration of the terminal seal portion 151A is different, and other configurations are the same as those of embodiment A1. The following describes the power storage device 400 of embodiment A4, focusing on the differences from embodiment A1.

Figure 20 is a cross-sectional view of a terminal seal portion 451A provided in an electricity storage device 400 of embodiment A4. The electricity storage device 400 does not have a tab film 140. In the terminal seal portion 451A of the electricity storage device 400, from the top, an exterior film 221, a packaging film for the electricity storage device 211, a metal terminal 130, a packaging film for the electricity storage device 212, and an exterior film 222 are laminated and integrated.

The end 221X of the flange portion 221A is located closer to the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. The end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the power storage device. The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the power storage device. The end portion 222X of the flange portion 222A is located closer to the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end portion 222X of the flange portion 222A may be located in the same position as the end portion 212X of the packaging film 212 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device.

[Characteristics of the energy storage device]
According to the electricity storage device 400, the number of parts is reduced because the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140. In addition, the manufacturing method of the electricity storage device 400 can be simplified.

[Embodiment A5]
The power storage device 500 of embodiment A5 differs from embodiment A4 in that the configuration of the terminal seal portion 451A is different, and the other configurations are the same as those of embodiment A4. The following describes the power storage device 500 of embodiment A5, focusing on the differences from embodiment A4.

Figure 21 is a cross-sectional view of a terminal seal portion 551A provided in the electricity storage device 500 of embodiment A5. In the terminal seal portion 551A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to the metal terminal 130. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the metal terminal 130.

The flange portion 221A of the exterior film 221 is joined to the metal terminal 130. The flange portion 222A of the exterior film 222 is joined to the metal terminal 130. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the electricity storage device 500, the inner packaging body 210 is covered by the outer packaging body 220, which prevents moisture and the like from entering the internal space S1 of the inner packaging body 210 from the outside. Moreover, according to the electricity storage device 500, the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140, which reduces the number of parts. Furthermore, the manufacturing method of the electricity storage device 500 can be simplified.

[Variations]
The above-described embodiments are examples of possible forms of the power storage device and the manufacturing method of the power storage device according to the present disclosure, and are not intended to limit the forms. The power storage device and the manufacturing method of the power storage device according to the present disclosure may take forms different from those exemplified in the embodiments. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Below, some examples of modified versions of each embodiment are shown. The following modified versions can be combined with each other as long as they are not technically inconsistent.

In the energy storage device 100 of embodiment A1, one outer packaging body 220 may be configured to house multiple inner packaging bodies 210 in a state in which the energy storage device elements 120 are housed. In this modification, the sizes of the multiple inner packaging bodies 210 may be different or the same. According to this modification, the multiple energy storage device elements 120 can be connected in series or parallel, so that the voltage can be easily adjusted.

In the electricity storage device 100 of embodiment A1, the electricity storage device packaging films 211, 212 do not need to be transparent. The electricity storage device packaging films 211, 212 only need to be at least gas permeable.

In the energy storage device 100 of embodiment A1, the inner packaging body 210 may be constructed by folding one energy storage device packaging film 211 and heat sealing the peripheral portion. Similarly, the outer packaging body 220 may be constructed by folding one exterior film 221 and heat sealing the peripheral portion.

<Embodiment B>
In the manufacturing process of the electricity storage device, generally, after the electricity storage device element is accommodated in the packaging film for the electricity storage device, the periphery of the packaging film for the electricity storage device is sealed to temporarily seal it. Then, an initial charge/discharge process and an aging process are performed. The packaging film for the electricity storage device provided in the secondary battery includes a metal layer and therefore has a shielding property. Therefore, when the electricity storage device element is sealed by the packaging film for the electricity storage device, it is not possible to check whether the periphery of the packaging film for the electricity storage device is properly sealed. Therefore, the electricity storage device cannot be manufactured suitably.

The invention according to embodiment B aims to provide a method for manufacturing an electricity storage device that can suitably manufacture an electricity storage device, and an electricity storage device manufactured by this manufacturing method.

The manufacturing method of an electricity storage device according to a first aspect of the invention in embodiment B is a manufacturing method of an electricity storage device, the electricity storage device comprising an electricity storage device element and an inner packaging body that houses the electricity storage device element, the inner packaging body being composed of a transparent electricity storage device packaging film, and including an inner packaging step of wrapping the electricity storage device element with the electricity storage device packaging film, and an inner sealing step, which is carried out after the inner packaging step, of sealing the electricity storage device packaging film so that the electricity storage device element is hermetically sealed by the electricity storage device packaging film.

The method for producing an electricity storage device according to a second aspect of the invention in embodiment B is the method for producing an electricity storage device according to the first aspect, in which the packaging film for the electricity storage device further has gas permeability, and further includes a degassing step that is carried out after the inner sealing step and releases gas generated from the electricity storage device element through the packaging film for the electricity storage device.

The manufacturing method for an electricity storage device according to the third aspect of the invention in embodiment B is the manufacturing method for an electricity storage device according to the second aspect, and in the inner packaging step, the electricity storage device element is wrapped in the packaging film for the electricity storage device that is substantially the same size as the inner packaging body of the finished electricity storage device.

The electric storage device according to the fourth aspect of the invention in embodiment B comprises an electric storage device element, an inner packaging body that houses the electric storage device element, and an outer packaging body that houses the inner packaging body in which the electric storage device element is housed, and the inner packaging body is made of a transparent packaging film for electric storage devices.

The electric storage device according to the fifth aspect of the invention in embodiment B is the electric storage device according to the fourth aspect, further comprising a metal terminal electrically connected to the electric storage device element and a tab film disposed between the inner packaging body and the metal terminal, the outer packaging body is joined to the inner packaging body, the inner packaging body and the metal terminal are joined via the tab film, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The sixth aspect of the invention according to embodiment B is the fourth aspect of the electric storage device, further comprising a metal terminal electrically connected to the electric storage device element, and a tab film disposed between the inner and outer packaging bodies and the metal terminals, the inner and outer packaging bodies being joined to the metal terminals via the tab film, and the entire inner packaging body being covered by the outer packaging body.

The seventh aspect of the invention according to embodiment B is the electric storage device according to the fourth aspect, further comprising a metal terminal electrically connected to the electric storage device element, the inner packaging body and the metal terminal are joined, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The electric storage device according to the eighth aspect of the invention in embodiment B is the electric storage device according to the fourth aspect, further comprising a metal terminal electrically connected to the electric storage device element, the inner packaging body and the outer packaging body are joined to the metal terminal, and the entire inner packaging body is covered by the outer packaging body.

The electricity storage device according to the ninth aspect of the invention in embodiment B is an electricity storage device according to any one of the third to eighth aspects, and the packaging film for the electricity storage device further has gas permeability.

[Embodiment B1]
FIG. 8 shows a plan view of the power storage device 100 according to the present embodiment B1. FIG. 9 is a cross-sectional view taken along the line D2-D2 in FIG. 8. In FIG. 8, a portion that is not visible from the outside is partially shown by dotted lines for reference. Hereinafter, for convenience of explanation, unless otherwise specified, the up-down direction in FIG. 8 is referred to as the "front-rear direction", the left-right direction is referred to as the "left-right direction", and the up-down direction in FIG. 9 is referred to as the "up-down direction". However, the orientation of the power storage device 100 during use is not limited to this. In addition, in FIG. 8, the relative positional relationship between the inner wrapping body 210 and the outer wrapping body 220 is simplified for the sake of simplicity of the drawing.

The energy storage device 100 comprises a housing 110, an energy storage device element 120, a pair of metal terminals 130, and a pair of tab films 140. The housing 110 comprises an internal space S1 and a peripheral seal portion 150. The energy storage device element 120 is housed in the internal space S1 of the housing 110. One end of the metal terminal 130 is joined to the energy storage device element 120, and the other end protrudes outward from the peripheral seal portion 150 of the housing 110. A portion of the area between one end and the other end of the metal terminal 130 is fused to the peripheral seal portion 150 via the tab film 140.

The container 110 includes a container 110A. The container 110A includes an inner packaging body 210 and an outer packaging body 220. The inner packaging body 210 contains the power storage device element 120. The outer packaging body 220 contains the inner packaging body 210 in which the power storage device element 120 is contained. An internal space S1 is formed inside the inner packaging body 210. The inner packaging body 210 includes packaging films 211 and 212 for the power storage device. The outer packaging body 220 includes exterior films 221 and 222. In the outer peripheral portion of the container 110A in a plan view, the inner packaging body 210 and the outer packaging body 220 are heat-sealed and fused to each other, thereby forming a peripheral seal portion 150. The peripheral seal portion 150 forms an internal space S1 of the container 110A that is isolated from the external space in the inner packaging body 210. The peripheral seal portion 150 defines the periphery of the internal space S1 of the container 110A. The heat seal mode referred to here may be heat fusion from a heat source, ultrasonic fusion, or the like. In any case, the peripheral seal portion 150 refers to the portion where the inner wrapping body 210 and the outer wrapping body 220 are fused together to form an integrated unit.

The peripheral seal portion 150 includes a top seal portion 151, a pair of side seal portions 152, 153, and a bottom seal portion 154. The top seal portion 151 includes a portion that is sealed by sandwiching the metal terminal 130 and the tab film 140 (hereinafter referred to as "terminal seal portion 151A"), and extends in the front-rear direction. The pair of side seal portions 152, 153 extend in the left-right direction. The side seal portion 152 and the side seal portion 153 face each other across the internal space S1. The bottom seal portion 154 faces the top seal portion 151 across the internal space S1. The bottom seal portion 154 extends in the front-rear direction.

9, the terminal seal portion 151A of the top seal portion 151 is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. This makes it easy to form the top seal portion 151. Note that the portion of the top seal portion 151 other than the terminal seal portion 151A, in other words, the portion where only the pair of tab films 140 are sandwiched between the inner packaging body 210 and the outer packaging body 220, is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. Furthermore, the outer portion of the terminal seal portion 151A of the top seal portion 151 (the left portion with the step as the boundary in FIG. 9) is made up of, from the top, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, and the packaging film for the power storage device 212, which are laminated and integrated together. Therefore, there is a step between the outer portion of the terminal seal portion 151A where the exterior films 221, 222 are not present and the inner portion of the terminal seal portion 151A where the exterior films 221, 222 are present (the right portion with the step as the boundary in FIG. 9), but FIG. 8 shows an overview of the area of the peripheral seal portion 150, and does not show the step as the boundary.

The electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are transparent overall from the viewpoint of suitable manufacturing of the electricity storage device 100. Below, preferred examples of the electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are described. In the following, when there is no particular distinction between the electricity storage device packaging films 211, 212, the electricity storage device packaging films 211, 212 may be collectively referred to as the electricity storage device packaging film 10.

The shape of the inner packaging body 210 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The inner packaging body 210 of this embodiment B1 has a shape as shown in FIG. 9, and is manufactured by heat-sealing a packaging film for an electricity storage device 212 formed into a tray shape and a packaging film for an electricity storage device 211 also formed into a tray shape and superimposed on the packaging film for an electricity storage device 212, along the outer periphery in a plan view. The packaging film for an electricity storage device 212 includes a flange portion 212A of a square ring shape corresponding to the outer periphery in a plan view, and a molded portion 212B that is continuous with the inner edge of the flange portion 212A and bulges downward from there. Similarly, the electricity storage device packaging film 211 includes a rectangular ring-shaped flange portion 211A that corresponds to the outer periphery in a plan view, and a flange portion 211B that is continuous with the inner edge of the flange portion 211A and bulges upward from the flange portion 211A. The electricity storage device packaging films 211 and 212 are overlapped such that the respective molded portions 211B and 212B bulge in opposite directions. In this state, the flange portion 211A of the electricity storage device packaging film 211 and the flange portion 212A of the electricity storage device packaging film 212 are heat-sealed so as to be integrated, forming a part of the peripheral seal portion 150. Note that one of the electricity storage device packaging films 211 and 212 may be in the form of a sheet.

The exterior films 221, 222 constituting the outer packaging body 220 are, for example, made of a resin molded product or film. The resin molded product referred to here can be manufactured by injection molding, compressed air molding, vacuum molding, blow molding, or other methods, and in-mold molding may be used to impart design and functionality. The type of resin may be polyolefin, polyester, nylon, ABS, or other materials. The film referred to here is, for example, a resin film that can be manufactured by an inflation method or a T-die method, or a resin film laminated on a metal foil or metal plate. The film referred to here may or may not be stretched, and may be a single-layer film or a multilayer film. The multilayer film referred to here may be manufactured by a coating method, may be a film in which multiple films are bonded together with an adhesive, or may be manufactured by a multilayer extrusion method.

The exterior films 221 and 222 can be configured in various ways, but in this embodiment B1, they are configured from a laminate film. The laminate film can be a laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated. The base layer functions as a base material for the exterior films 221 and 222, and is typically a resin layer that forms the outer layer side of the outer packaging body 220 and has insulating properties. The barrier layer has a function of preventing at least moisture and the like from penetrating into the power storage device 100 in addition to improving the strength of the exterior films 221 and 222, and is typically a metal layer made of aluminum alloy foil or the like. The heat-sealable resin layer is typically made of a heat-sealable resin such as polyolefin, and forms the innermost layer of the outer packaging body 220.

The shape of the outer packaging body 220 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The container 110A of this embodiment B1 has a shape as shown in FIG. 9, and is manufactured by heat-sealing an exterior film 222 formed into a tray shape and an exterior film 221 similarly formed into a tray shape and superimposed on the exterior film 222 along the outer periphery in a plan view. The exterior film 222 includes a square ring-shaped flange portion 222A corresponding to the outer periphery in a plan view, and a molded portion 222B that is continuous with the inner edge of the flange portion 222A and bulges downward therefrom. Similarly, the exterior film 221 includes a square ring-shaped flange portion 221A corresponding to the outer periphery in a plan view, and a flange portion 221B that is continuous with the inner edge of the flange portion 221A and bulges upward therefrom. The exterior films 221 and 222 are overlapped so that the respective molded portions 221B and 222B bulge in opposite directions. In this state, the flange portion 221A of the exterior film 221 and the flange portion 222A of the exterior film 222 are heat sealed to be integrated together, forming a part of the peripheral seal portion 150. Note that one of the exterior films 221 and 222 may be in the form of a sheet.

As shown in FIG. 9, in the terminal seal portion 151A, a portion of the flange portion 211A of the packaging film 211 for the power storage device is joined to one of the tab films 140. A portion of the flange portion 212A of the packaging film 212 for the power storage device is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the electricity storage device. The end 221X of the flange portion 221A is located closer to the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device.

The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the electricity storage device. The end 222X of the flange portion 222A is located closer to the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 222X of the flange portion 222A may be located in the same position as the end 212X of the packaging film 212 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device.

The power storage device element 120 has at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, a lithium ion battery (secondary battery) or a power storage member such as a capacitor.

The metal terminal 130 is a metal terminal used for inputting and outputting power to and from the power storage device element 120. The metal terminal 130 is arranged, for example, in the top seal portion 151 of the container 110A, with one terminal constituting a positive electrode side terminal and the other terminal constituting a negative electrode side terminal. One end in the left-right direction of each metal terminal 130 is electrically connected to an electrode (positive electrode or negative electrode) of the power storage device element 120 in the internal space S1 of the container 110A, and the other end protrudes outward from the peripheral seal portion 150. The above-mentioned form of the power storage device 100 is particularly preferable for use in electric vehicles such as electric vehicles and hybrid vehicles that use a large number of power storage devices 100 connected in series at high voltage. The mounting positions of the two metal terminals 130 that constitute the positive and negative electrode terminals are not particularly limited, and may be arranged, for example, in the side seal portions 152, 153 or bottom seal portion 154 of the peripheral seal portion 150.

The metal material constituting the metal terminal 130 is, for example, aluminum, nickel, copper, etc. When the power storage device element 120 is a lithium ion battery, the metal terminal 130 connected to the positive electrode is typically made of aluminum, etc., and the metal terminal 130 connected to the negative electrode is typically made of copper, nickel, etc.

The tab film 140 is a so-called adhesive film, and is configured to adhere to both the electricity storage device packaging films 211, 212 and the metal terminal 130. By using the tab film 140, the metal terminal 130 and the innermost layer (thermally adhesive resin layer) of the electricity storage device packaging films 211, 212 can be fixed together even if they are made of different materials. The tab film 140 is integrated by being fused and fixed to the metal terminal 130 in advance, and the electricity storage device packaging films 211, 212 are fused to the metal terminal 130 to which the tab film 140 is fixed.

[Method of manufacturing electricity storage device]
10 is a flowchart showing an example of a method for manufacturing the power storage device 100. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging process of step S11, as shown in FIG. 11, the formed electricity storage device packaging films 211, 212 are wrapped around the electricity storage device element 120. In the electricity storage device 100 of this embodiment B1, since the electricity storage device packaging films 211, 212 are gas permeable, there is no need to form a sub-chamber for temporarily storing the gas generated from the electricity storage device element 120 in the initial filling process described below. Therefore, in the inner packaging process, the electricity storage device element 120 is wrapped around the electricity storage device packaging films 211, 212 that are substantially the same size as the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the finished electricity storage device 100. This simplifies the manufacturing process of the electricity storage device 100. In addition, the amount of material used for the electricity storage device 100 can be reduced. "Substantially the same size" includes cases where the size is larger than the electricity storage device packaging films 211, 212 included in the inner packaging body 210 of the finished electricity storage device 100 to the extent that a sub-chamber cannot be formed. Note that the electricity storage device element 120 is connected to the metal terminal 130 in advance, and the tab film 140 is joined to the metal terminal 130.

The first inner sealing process in step S12 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 12, the portions of the periphery of the electricity storage device packaging films 211, 212 that correspond to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed. Completion of the first inner sealing process forms an opening 213 in the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed. After the first inner sealing process, the vacuum drying process in step S13 is carried out.

The electrolyte injection process in step S14 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 12).

The second inner sealing process in step S15 is carried out after the electrolyte injection process. As shown in FIG. 10, in the second inner sealing process, the opening 213 is closed by sealing the portion of the periphery of the packaging films 211, 212 for the electricity storage device where the side seal portion 153 is to be formed. After the second inner sealing process, the initial charge/discharge process in step S16 and the aging process in step S17 are carried out in sequence.

The degassing process in step S18 is carried out in parallel with the initial charge/discharge process and the aging process. In this embodiment B1, the packaging films 211 and 212 for the electricity storage device are gas permeable, so that gases such as carbon dioxide generated from the electricity storage device element 120 during the initial charge/discharge process and the aging process are discharged to the outside through the packaging films 211 and 212 for the electricity storage device. After the degassing process, the main charging process in step S19 is carried out.

The outer packaging process in step S20 is carried out after the main charging process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S21 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221 and 222 is sealed to form the periphery seal portion 150.

[Characteristics of the energy storage device]
According to the electricity storage device 100, since the electricity storage device packaging films 211 and 212 have transparency, after the first inner sealing step or the second inner sealing step is completed, it is possible to easily check whether the electricity storage device packaging film 211 and the electricity storage device packaging film 212 are properly sealed. Therefore, the electricity storage device 100 can be suitably manufactured. The state in which the electricity storage device packaging film 211 and the electricity storage device packaging film 212 are not properly sealed includes, for example, a first state, a second state, or a third state. The first state is a state in which the electricity storage device packaging film 211 and the electricity storage device packaging film 212 are sealed with a foreign object caught between them. The second state is a state in which a part of the part that should be sealed is not sealed. The third state is a state in which a part that should not be sealed is sealed.

[Embodiment B2]
The electricity storage device 100 of embodiment B2 differs from embodiment B1 in that the electricity storage device packaging films 211, 212 are not gas permeable, or in that, compared to embodiment B1, they do not have gas permeability to the extent that the degassing step of step S18 described above is performed, but the other configurations are similar to those of embodiment B1. The electricity storage device 100 of embodiment B2 will be described below, focusing on the differences from embodiment B2.

[Method of manufacturing electricity storage device]
11 is a flowchart showing an example of a method for manufacturing the power storage device 100 according to embodiment B2. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging step of step S31, as shown in FIG. 15, the formed electricity storage device packaging films 211, 212 are used to wrap the electricity storage device element 120. In the electricity storage device 100 of this embodiment B2, since the electricity storage device packaging films 211, 212 are not gas permeable, it is preferable to form a sub-chamber 214 for temporarily storing gas generated from the electricity storage device element 120 during the initial filling step or the like. For this reason, in the inner packaging step, the electricity storage device element 120 is wrapped in the electricity storage device packaging films 211, 212 that are larger than the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the completed electricity storage device 100. In the sub-chamber 214 of the electricity storage device packaging films 211, 212, a storage chamber 215 for storing more gas generated from the electricity storage device element 120 is formed.

The first inner sealing process of step S32 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 16, the portions of the periphery of the electricity storage device packaging films 211, 212 corresponding to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed so as to extend to the auxiliary chamber 214. Completion of the first inner sealing process forms an opening 213 in a portion 216 that faces the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed, across the auxiliary chamber 214. After the first inner sealing process, the vacuum drying process of step S33 is carried out.

The electrolyte injection process in step S34 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 16).

The second inner sealing step of step S35 is carried out after the electrolyte injection step. As shown in FIG. 17, in the second inner sealing step, the opening 213 is closed by sealing the portion 216 of the periphery of the packaging films 211, 212 for the electricity storage device, where the side seal portion 153 is to be formed, and the portion 216 facing the auxiliary chamber 214. After the second inner sealing step, the initial charge/discharge step of step S36 and the aging step of step S37 are carried out in sequence.

The degassing process in step S38 is carried out after the aging process. In the degassing process, gases such as carbon dioxide generated from the electricity storage device element 120 are temporarily stored in the auxiliary chamber 214 of the electricity storage device packaging films 211 and 212.

The auxiliary chamber removal process in step S39 is carried out after the degassing process. In the auxiliary chamber removal process, the auxiliary chamber 214 is removed by cutting the packaging films 211, 212 for the electricity storage device along the dashed line XA shown in Figure 17 so that the auxiliary chamber 214 is the same size as the inner packaging body 210 of the completed electricity storage device 100.

The inner sealing process of step S40 is carried out after the auxiliary chamber removal process. In the inner sealing process, as shown in FIG. 18, the portion of the periphery of the packaging films 211, 212 for the electricity storage device that corresponds to the side seal portion 153 is sealed. After the inner sealing process, the main charging process of step S41 is carried out.

The outer packaging process in step S42 is carried out after the main charging process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S43 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221 and 222 is sealed to form the periphery seal portion 150.

[Characteristics of the energy storage device]
According to the electricity storage device 100 of embodiment B3, since the electricity storage device packaging films 211 and 212 have transparency, the same effects as those of the electricity storage device 100 of embodiment B1 can be obtained.

[Embodiment B3]
The power storage device 300 of embodiment B3 differs from embodiment B1 in that the configuration of the terminal seal portion 151A is different, and other configurations are the same as those of embodiment B1. The following describes the power storage device 300 of embodiment B3, focusing on the differences from embodiment B1.

Figure 19 is a cross-sectional view of a terminal seal portion 351A provided in an electricity storage device 300 of embodiment B3. In the terminal seal portion 351A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to one tab film 140. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to one of the tab films 140. The flange portion 222A of the exterior film 222 is joined to the other tab film 140. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the power storage device 300, the inner packaging body 210 is covered by the outer packaging body 220, so that intrusion of moisture and the like from the outside into the internal space S1 of the inner packaging body 210 is suppressed.

[Embodiment B4]
The power storage device 400 of embodiment B4 differs from embodiment B1 in that the configuration of the terminal seal portion 151A is different, and other configurations are the same as those of embodiment B1. The following describes the power storage device 400 of embodiment B4, focusing on the differences from embodiment B1.

Figure 20 is a cross-sectional view of a terminal seal portion 451A provided in an electricity storage device 400 of embodiment B4. The electricity storage device 400 does not have a tab film 140. In the terminal seal portion 451A of the electricity storage device 400, from the top, an exterior film 221, a packaging film for the electricity storage device 211, a metal terminal 130, a packaging film for the electricity storage device 212, and an exterior film 222 are laminated and integrated.

The end 221X of the flange portion 221A is located closer to the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. The end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the power storage device. The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the power storage device. The end portion 222X of the flange portion 222A is located closer to the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end portion 222X of the flange portion 222A may be located in the same position as the end portion 212X of the packaging film 212 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device.

[Characteristics of the energy storage device]
According to the electricity storage device 400, the number of parts is reduced because the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140. In addition, the manufacturing method of the electricity storage device 400 can be simplified.

[Embodiment B5]
The power storage device 500 of embodiment B5 differs from embodiment B4 in that the configuration of the terminal seal portion 451A is different, and other configurations are the same as those of embodiment B4. The following describes the power storage device 500 of embodiment B5, focusing on the differences from embodiment B4.

Figure 21 is a cross-sectional view of a terminal seal portion 551A provided in an electricity storage device 500 of embodiment B5. In the terminal seal portion 551A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to the metal terminal 130. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the metal terminal 130.

The flange portion 221A of the exterior film 221 is joined to the metal terminal 130. The flange portion 222A of the exterior film 222 is joined to the metal terminal 130. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the electricity storage device 500, the inner packaging body 210 is covered by the outer packaging body 220, which prevents moisture and the like from entering the internal space S1 of the inner packaging body 210 from the outside. Moreover, according to the electricity storage device 500, the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140, which reduces the number of parts. Furthermore, the manufacturing method of the electricity storage device 500 can be simplified.

[Variations]
The above-mentioned respective embodiments B are examples of possible forms of the electricity storage device and the manufacturing method of the electricity storage device according to the present disclosure, and are not intended to limit the forms. The electricity storage device and the manufacturing method of the electricity storage device according to the present disclosure may take forms different from those exemplified in each embodiment. One example is a form in which part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Below, some examples of modified forms of each embodiment are shown. Note that the following modified forms can be combined with each other as long as there is no technical contradiction.

In the energy storage device 100 of embodiment B1, one outer packaging body 220 may be configured to house multiple inner packaging bodies 210 in a state in which the energy storage device elements 120 are housed. In this modification, the sizes of the multiple inner packaging bodies 210 may be different or the same. According to this modification, the multiple energy storage device elements 120 can be connected in series or parallel, so that the voltage can be easily adjusted.

In the electricity storage device 100 of embodiment B1, the electricity storage device packaging films 211, 212 do not need to be gas permeable. The electricity storage device packaging films 211, 212 only need to be at least transparent.

In the energy storage device 100 of embodiment B1, the inner packaging body 210 may be constructed by folding one energy storage device packaging film 211 and heat sealing the peripheral portion. Similarly, the outer packaging body 220 may be constructed by folding one exterior film 221 and heat sealing the peripheral portion.

<Embodiment C>
In addition to the functions that electricity storage devices usually have, it is preferable that the electricity storage device has a function with high added value.

The object of the invention of embodiment C is to provide an electricity storage device with high added-value functions.

The energy storage device according to the first aspect of the invention in embodiment C comprises an energy storage device element, an inner packaging body that houses the energy storage device element, an outer packaging body that houses the inner packaging body in which the energy storage device element is housed, and a functional object that is disposed between the inner packaging body and the outer packaging body, and the functional object has shock absorbing properties.

The energy storage device according to the second aspect of the invention in embodiment C includes an energy storage device element, an inner packaging body that houses the energy storage device element, an outer packaging body that houses the inner packaging body in which the energy storage device element is housed, and a functional object that is disposed between the inner packaging body and the outer packaging body, and the functional object has flame retardancy.

The energy storage device according to the third aspect of the invention in embodiment C comprises an energy storage device element, an inner packaging body that houses the energy storage device element, an outer packaging body that houses the inner packaging body in which the energy storage device element is housed, and a functional object that is disposed between the inner packaging body and the outer packaging body, and the functional object has a cooling property.

The electric energy storage device according to the fourth aspect of the invention in embodiment C comprises an electric energy storage device element, an inner packaging body that houses the electric energy storage device element, an outer packaging body that houses the inner packaging body in which the electric energy storage device element is housed, and a functional object that is disposed between the inner packaging body and the outer packaging body, and the functional object has fire extinguishing properties.

The energy storage device according to the fifth aspect of the invention in embodiment C comprises an energy storage device element, an inner packaging body that houses the energy storage device element, and an outer packaging body that houses the inner packaging body in which the energy storage device element is housed, and at least one of the inner packaging body and the outer packaging body has at least one of shock absorption, flame retardancy, cooling properties, and fire extinguishing properties.

The sixth aspect of the invention according to embodiment C is an electricity storage device according to any one of the first to fifth aspects, in which the inner packaging body has at least one of transparency and gas permeability.

The seventh aspect of the invention according to embodiment C is an electric storage device according to any one of the first to sixth aspects, further comprising a metal terminal electrically connected to the electric storage device element and a tab film disposed between the inner packaging body and the metal terminal, the outer packaging body is joined to the inner packaging body, the inner packaging body and the metal terminal are joined via the tab film, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The electric storage device according to the eighth aspect of the invention in embodiment C is an electric storage device according to any one of the first to sixth aspects, further comprising a metal terminal electrically connected to the electric storage device element, and a tab film disposed between the inner and outer packaging bodies and the metal terminals, the inner and outer packaging bodies being joined to the metal terminals via the tab film, and the entire inner packaging body being covered by the outer packaging body.

The electricity storage device according to the ninth aspect of the invention in embodiment C is an electricity storage device according to any one of the first to sixth aspects, further comprising a metal terminal electrically connected to the electricity storage device element, the inner packaging body and the metal terminal are joined, and at least a portion of the outer edge of the inner packaging body is exposed from the outer packaging body.

The electricity storage device according to a tenth aspect of the invention in embodiment C is an electricity storage device according to any one of the first to sixth aspects, further comprising a metal terminal electrically connected to the electricity storage device element, the inner packaging body and the outer packaging body are joined to the metal terminal, and the entire inner packaging body is covered by the outer packaging body.

[Embodiment C1]
FIG. 8 shows a plan view of the power storage device 100 according to the present embodiment C1. FIG. 22 is a cross-sectional view taken along the line D2-D2 in FIG. 8. In FIG. 8, a portion that is not visible from the outside is partially shown by dotted lines for reference. In the following, for convenience of explanation, unless otherwise specified, the up-down direction in FIG. 8 is referred to as the "front-rear direction", the left-right direction is referred to as the "left-right direction", and the up-down direction in FIG. 22 is referred to as the "up-down direction". However, the orientation of the power storage device 100 during use is not limited to this. In addition, in FIG. 8, the relative positional relationship between the inner wrapping body 210 and the outer wrapping body 220 is simplified for the sake of simplicity of the drawing.

The energy storage device 100 comprises a housing 110, an energy storage device element 120, a pair of metal terminals 130, and a pair of tab films 140. The housing 110 comprises an internal space S1 and a peripheral seal portion 150. The energy storage device element 120 is housed in the internal space S1 of the housing 110. One end of the metal terminal 130 is joined to the energy storage device element 120, and the other end protrudes outward from the peripheral seal portion 150 of the housing 110. A portion of the area between one end and the other end of the metal terminal 130 is fused to the peripheral seal portion 150 via the tab film 140.

The container 110 includes a container 110A. The container 110A includes an inner packaging body 210 and an outer packaging body 220. The inner packaging body 210 contains the power storage device element 120. The outer packaging body 220 contains the inner packaging body 210 in which the power storage device element 120 is contained. An internal space S1 is formed inside the inner packaging body 210. The inner packaging body 210 includes packaging films 211 and 212 for the power storage device. The outer packaging body 220 includes exterior films 221 and 222. In the outer peripheral portion of the container 110A in a plan view, the inner packaging body 210 and the outer packaging body 220 are heat-sealed and fused to each other, thereby forming a peripheral seal portion 150. The peripheral seal portion 150 forms an internal space S1 of the container 110A that is isolated from the external space in the inner packaging body 210. The peripheral seal portion 150 defines the periphery of the internal space S1 of the container 110A. The heat seal mode referred to here may be heat fusion from a heat source, ultrasonic fusion, or the like. In any case, the peripheral seal portion 150 refers to the portion where the inner wrapping body 210 and the outer wrapping body 220 are fused together to form an integrated unit.

The peripheral seal portion 150 includes a top seal portion 151, a pair of side seal portions 152, 153, and a bottom seal portion 154. The top seal portion 151 includes a portion that is sealed by sandwiching the metal terminal 130 and the tab film 140 (hereinafter referred to as "terminal seal portion 151A"), and extends in the front-rear direction. The pair of side seal portions 152, 153 extend in the left-right direction. The side seal portion 152 and the side seal portion 153 face each other across the internal space S1. The bottom seal portion 154 faces the top seal portion 151 across the internal space S1. The bottom seal portion 154 extends in the front-rear direction.

22, the terminal seal portion 151A of the top seal portion 151 is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. This makes it easy to form the top seal portion 151. Note that the portion of the top seal portion 151 other than the terminal seal portion 151A, in other words, the portion where only the pair of tab films 140 are sandwiched between the inner packaging body 210 and the outer packaging body 220, is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. Furthermore, the outer portion of the terminal seal portion 151A of the top seal portion 151 (the left portion with the step as the boundary in FIG. 22) is made up of, from the top, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, and the packaging film for the power storage device 212, which are laminated and integrated. Therefore, there is a step between the outer portion of the terminal seal portion 151A where the exterior films 221, 222 are not present and the inner portion of the terminal seal portion 151A where the exterior films 221, 222 are present (the right portion with the step as the boundary in FIG. 22), but FIG. 8 shows an overview of the area of the peripheral seal portion 150, and does not show the step as the boundary.

From the viewpoint of suitably manufacturing the electricity storage device 100, the electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are preferably transparent overall. From the viewpoint of easily manufacturing the electricity storage device 100, the electricity storage device packaging films 211, 212 are preferably gas permeable. Below, preferred examples of the electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are described. Note that below, when there is no particular distinction between the electricity storage device packaging films 211, 212, the electricity storage device packaging films 211, 212 may be collectively referred to as the electricity storage device packaging film 10.

The shape of the inner packaging body 210 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The inner packaging body 210 of this embodiment C1 has a shape as shown in FIG. 22 and is manufactured by heat sealing a packaging film for an electricity storage device 212 formed into a tray shape and a packaging film for an electricity storage device 211 also formed into a tray shape and superimposed on the packaging film for an electricity storage device 212, along the outer periphery in a plan view. The packaging film for an electricity storage device 212 includes a flange portion 212A of a square ring shape corresponding to the outer periphery in a plan view, and a molded portion 212B that is continuous with the inner edge of the flange portion 212A and bulges downward from there. Similarly, the electricity storage device packaging film 211 includes a rectangular ring-shaped flange portion 211A that corresponds to the outer periphery in a plan view, and a flange portion 211B that is continuous with the inner edge of the flange portion 211A and bulges upward from the flange portion 211A. The electricity storage device packaging films 211 and 212 are overlapped such that the respective molded portions 211B and 212B bulge in opposite directions. In this state, the flange portion 211A of the electricity storage device packaging film 211 and the flange portion 212A of the electricity storage device packaging film 212 are heat-sealed so as to be integrated, forming a part of the peripheral seal portion 150. Note that one of the electricity storage device packaging films 211 and 212 may be in the form of a sheet.

The exterior films 221, 222 constituting the outer packaging body 220 are, for example, made of a resin molded product or film. The resin molded product referred to here can be manufactured by injection molding, compressed air molding, vacuum molding, blow molding, or other methods, and in-mold molding may be used to impart design and functionality. The type of resin may be polyolefin, polyester, nylon, ABS, or other materials. The film referred to here is, for example, a resin film that can be manufactured by an inflation method or a T-die method, or a resin film laminated on a metal foil or metal plate. The film referred to here may or may not be stretched, and may be a single-layer film or a multilayer film. The multilayer film referred to here may be manufactured by a coating method, may be a film in which multiple films are bonded together with an adhesive, or may be manufactured by a multilayer extrusion method.

The exterior films 221, 222 can be configured in various ways, but in this embodiment C1, they are configured from a laminate film. The laminate film can be a laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated. The base layer functions as a base material for the exterior films 221, 222, and is typically a resin layer having insulating properties that forms the outer layer side of the outer packaging body 220. The barrier layer has a function of preventing at least moisture and the like from penetrating into the power storage device 100 in addition to improving the strength of the exterior films 221, 222, and is typically a metal layer made of aluminum alloy foil or the like. The heat-sealable resin layer is typically made of a heat-sealable resin such as polyolefin, and forms the innermost layer of the outer packaging body 220.

The shape of the outer packaging body 220 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The container 110A of this embodiment C1 has a shape as shown in FIG. 22 and is manufactured by heat-sealing an exterior film 222 formed into a tray shape and an exterior film 221 similarly formed into a tray shape and superimposed on the exterior film 222 along the outer periphery in a plan view. The exterior film 222 includes a square ring-shaped flange portion 222A corresponding to the outer periphery in a plan view, and a molded portion 222B that is continuous with the inner edge of the flange portion 222A and bulges downward therefrom. Similarly, the exterior film 221 includes a square ring-shaped flange portion 221A corresponding to the outer periphery in a plan view, and a flange portion 221B that is continuous with the inner edge of the flange portion 221A and bulges upward therefrom. The exterior films 221 and 222 are overlapped so that the respective molded portions 221B and 222B bulge in opposite directions. In this state, the flange portion 221A of the exterior film 221 and the flange portion 222A of the exterior film 222 are heat sealed to be integrated together, forming a part of the peripheral seal portion 150. Note that one of the exterior films 221 and 222 may be in the form of a sheet.

As shown in FIG. 22, in the terminal seal portion 151A, a portion of the flange portion 211A of the packaging film 211 for the power storage device is joined to one of the tab films 140. A portion of the flange portion 212A of the packaging film 212 for the power storage device is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the electricity storage device. The end 221X of the flange portion 221A is located closer to the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device.

The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the electricity storage device. The end 222X of the flange portion 222A is located closer to the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 222X of the flange portion 222A may be located in the same position as the end 212X of the packaging film 212 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device.

The power storage device element 120 has at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, a lithium ion battery (secondary battery) or a power storage member such as a capacitor.

The metal terminal 130 is a metal terminal used for inputting and outputting power to and from the power storage device element 120. The metal terminal 130 is arranged, for example, in the top seal portion 151 of the container 110A, with one terminal constituting a positive electrode side terminal and the other terminal constituting a negative electrode side terminal. One end in the left-right direction of each metal terminal 130 is electrically connected to an electrode (positive electrode or negative electrode) of the power storage device element 120 in the internal space S1 of the container 110A, and the other end protrudes outward from the peripheral seal portion 150. The above-mentioned form of the power storage device 100 is particularly preferable for use in electric vehicles such as electric vehicles and hybrid vehicles that use a large number of power storage devices 100 connected in series at high voltage. The mounting positions of the two metal terminals 130 that constitute the positive and negative electrode terminals are not particularly limited, and may be arranged, for example, in the side seal portions 152, 153 or bottom seal portion 154 of the peripheral seal portion 150.

The metal material constituting the metal terminal 130 is, for example, aluminum, nickel, copper, etc. When the power storage device element 120 is a lithium ion battery, the metal terminal 130 connected to the positive electrode is typically made of aluminum, etc., and the metal terminal 130 connected to the negative electrode is typically made of copper, nickel, etc.

The tab film 140 is a so-called adhesive film, and is configured to adhere to both the electricity storage device packaging films 211, 212 and the metal terminal 130. By using the tab film 140, the metal terminal 130 and the innermost layer (thermally adhesive resin layer) of the electricity storage device packaging films 211, 212 can be fixed together even if they are made of different materials. The tab film 140 is integrated by being fused and fixed to the metal terminal 130 in advance, and the electricity storage device packaging films 211, 212 are fused to the metal terminal 130 to which the tab film 140 is fixed.

The power storage device 100 according to the present embodiment C1 includes a functional object 230 so as to have a high added-value function in addition to the functions of a general power storage device. The functional object 230 has at least one function of shock absorption, flame retardancy, cooling, and fire extinguishing. The functional object 230 is disposed between the inner wrapping body 210 and the outer wrapping body 220. The specific form of the functional object 230 can be selected arbitrarily. The functional object 230 may be in the form of a sheet such as a film, a liquid that can be applied to a film, or a granular or liquid form having a predetermined fluidity (viscosity).

When the functional object 230 is in the form of a sheet such as a film, the functional object 230 is, for example, wrapped around the inner packaging body 210 and joined to the inner packaging body 210. The functional object 230 may be joined to the inner packaging body 210 so as to cover at least a portion of the surface of the inner packaging body 210, but it is preferable that the functional object 230 is joined to the inner packaging body 210 so as to cover substantially the entire surface of the inner packaging body 210.

When the functional object 230 is a liquid that can be applied to a film or the like, the functional object 230 is applied to the surface of the inner packaging body 210 or the inner surface of the outer packaging body 220. The functional object 230 may be applied to at least a portion of the surface of the inner packaging body 210, but it is preferable that the functional object 230 is applied to substantially the entire surface of the inner packaging body 210. Note that the functional object 230 being a liquid that can be applied to a film or the like includes a state in which it can be sprayed onto the inner packaging body 210 and the outer packaging body 220 by a spray or the like.

When the functional object 230 is in a granular or liquid form having a predetermined fluidity (viscosity), the functional object 230 is filled into the space between the inner packaging body 210 and the outer packaging body 220. The functional object 230 may be filled into at least a portion of the space between the inner packaging body 210 and the outer packaging body 220, but it is preferable that the functional object 230 is filled into almost the entire space between the inner packaging body 210 and the outer packaging body 220.

The functional object 230 having shock absorbing properties is, for example, a non-crosslinked highly expanded polyethylene sheet, an electron beam crosslinked highly expanded polyethylene sheet, a heat-welded composite highly expanded polyethylene sheet, or nitrile rubber.

The flame-retardant functional object 230 is, for example, a flame-retardant polycarbonate film or a flame-retardant polyethylene terephthalate film.

The functional object 230 having cooling properties is, for example, a highly thermally conductive film, a highly thermally conductive adhesive sheet, or a highly thermally conductive graphite sheet.

The functional object 230 having fire extinguishing properties is, for example, a fire extinguishing agent or a film containing a fire extinguishing agent (hereinafter referred to as a "fire-resistant film"). The fire extinguishing agent is, for example, a common powder-based fire extinguishing agent such as potassium salt, sodium bicarbonate, or phosphate, an ABC fire extinguishing agent, a BC fire extinguishing agent, or sand. When a fire extinguishing agent is used as the functional object 230, a fire extinguishing agent that does not contain water is preferable from the viewpoint of suppressing a decrease in the function of the power storage device 100.

A known fireproof film can be used as the fireproof film. The fireproof film is, for example, a laminated film having a substrate (substrate layer) and a fire-extinguishing agent-containing layer in this order. The fire-extinguishing agent-containing layer may be provided on at least a portion of one surface of the substrate, but is preferably provided on the entire surface of the substrate. The substrate is within the substrate and has a region carrying the fire-extinguishing agent component and binder resin on the side of the fire-extinguishing agent-containing layer.

The fireproof film can be used with its extinguishing agent-containing layer facing an object that may ignite. In this embodiment C1, the fireproof film is bonded to the inner surface of the outer wrapping body 220 so that the extinguishing agent-containing layer faces the surface of the inner wrapping body 210. For example, if the power storage device element 120 ignites, initial extinguishing is performed by the aerosol generated from the extinguishing agent-containing layer.

The substrate has voids, and may be, for example, a nonwoven fabric made by entangling nonflammable or flame-retardant fibers, or a woven fabric made by weaving nonflammable or flame-retardant fibers. Examples of nonflammable or flame-retardant fibers include glass fibers, ceramic fibers, metal fibers, cellulose fibers, polyester fibers, carbon fibers, graphite fibers, and thermosetting resin fibers. From the viewpoint of excellent nonflammability, glass fibers and ceramic fibers can be used. Examples of substrates include glass cloth and nonflammable paper. As the substrate, a nonflammable substrate that meets the first class fire resistance specified in JIS Z 2150-1966 can also be used.

The supported regions in the substrate are formed when a coating film is formed on the surface of the substrate using a coating liquid containing the extinguishing agent component and the binder resin, and a portion of the coating liquid penetrates into the substrate. The substrate can be said to have supported regions of the extinguishing agent component and the binder resin, and non-supported regions.

The extinguishing agent-containing layer is a layer that contains an extinguishing agent component and a binder resin. The extinguishing agent component generates an aerosol by combustion. The extinguishing agent component contains, for example, at least an inorganic oxidizing agent and a radical generator. The radical generator has the effect of stabilizing combustion radicals and suppressing the chain reaction of combustion (negative catalytic action).

[Method of manufacturing electricity storage device]
23 is a flowchart showing an example of a method for manufacturing the power storage device 100. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging process of step S11, as shown in FIG. 24, the formed electricity storage device packaging films 211, 212 are wrapped around the electricity storage device element 120. In the electricity storage device 100 of this embodiment C1, since the electricity storage device packaging films 211, 212 are gas permeable, there is no need to form a sub-chamber for temporarily storing the gas generated from the electricity storage device element 120 in the initial filling process described below. Therefore, in the inner packaging process, the electricity storage device element 120 is wrapped around the electricity storage device packaging films 211, 212 that are substantially the same size as the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the finished electricity storage device 100. Therefore, the manufacturing process of the electricity storage device 100 can be simplified. In addition, the amount of material used for the electricity storage device 100 can be reduced. "Substantially the same size" includes cases where the size is larger than the electricity storage device packaging films 211, 212 included in the inner packaging body 210 of the finished electricity storage device 100 to the extent that a sub-chamber cannot be formed. Note that the electricity storage device element 120 is connected to the metal terminal 130 in advance, and the tab film 140 is joined to the metal terminal 130.

The first inner sealing process in step S12 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 12, the portions of the periphery of the electricity storage device packaging films 211, 212 that correspond to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed. Completion of the first inner sealing process forms an opening 213 in the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed. After the first inner sealing process, the vacuum drying process in step S13 is carried out.

The electrolyte injection process in step S14 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 12).

The second inner sealing process of step S15 is performed after the electrolyte injection process. As shown in FIG. 23, in the second inner sealing process, the opening 213 is closed by sealing the portion of the periphery of the packaging films 211 and 212 for the electricity storage device where the side seal portion 153 is to be formed. According to the electricity storage device 100, since the packaging films 211 and 212 for the electricity storage device have transparency, it is easy to check whether the packaging films 211 and 212 for the electricity storage device are properly sealed after the first inner sealing process or the second inner sealing process is completed. Therefore, the electricity storage device 100 can be suitably manufactured. The state in which the packaging films 211 and 212 for the electricity storage device are not properly sealed includes, for example, the first state, the second state, or the third state. The first state is a state in which the packaging films 211 and 212 for the electricity storage device are sealed with a foreign object in between. The second state is a state in which a part that should be sealed is not sealed. The third state is a state in which a part that should not be sealed is sealed. After the second inner sealing process, the initial charge/discharge process of step S16 and the aging process of step S17 are carried out in order.

The degassing process in step S18 is carried out in parallel with the initial charge/discharge process and the aging process. In this embodiment C1, the packaging films 211 and 212 for the electricity storage device are gas permeable, so that gases such as carbon dioxide generated from the electricity storage device element 120 during the initial charge/discharge process and the aging process are discharged to the outside through the packaging films 211 and 212 for the electricity storage device. After the degassing process, the main charging process in step S19 is carried out.

The placement process of step S20 is carried out after this filling process. In the placement process, the functional object 230 is placed between the inner packaging body 210 and the outer packaging body 230 depending on the specific form of the functional object 230. When the functional object 230 is in the form of a sheet such as a film, the functional object 230 is, for example, wrapped around the inner packaging body 210 and joined to the inner packaging body 210. When the functional object 230 is a liquid that can be applied to a film or the like, the functional object 230 is applied to the surface of the inner packaging body 210 or the inner surface of the outer packaging body 220.

The outer packaging process of step S21 is carried out after the arrangement process. In the outer packaging process, the inner packaging body 210 containing the energy storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S22 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221, 222 is sealed to form the periphery seal portion 150. If the functional object 230 is in a granular or liquid form with a predetermined fluidity (viscosity), the placement process may be carried out in the outer sealing process, for example, by filling the opening in the portion where the bottom seal portion 154 is to be formed after the top seal portion 151, side seal portions 152, 153 of the periphery seal portion 150 are formed.

[Characteristics of the energy storage device]
The power storage device 100 has high added value because it includes the functional object 230 .

[Embodiment C2]
The electricity storage device 100 of embodiment C2 differs from embodiment C1 in that the electricity storage device packaging films 211, 212 are not gas permeable, or in that, compared to embodiment C1, they do not have gas permeability to the extent that the degassing step of step S18 described above is performed, but the other configurations are the same as those of embodiment C1. The electricity storage device 100 of embodiment C2 will be described below, focusing on the differences from embodiment C2.

[Method of manufacturing electricity storage device]
24 is a flowchart showing an example of a method for manufacturing the power storage device 100 according to embodiment C2. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging step of step S31, as shown in FIG. 15, the formed electricity storage device packaging films 211, 212 are used to wrap the electricity storage device element 120. In the electricity storage device 100 of this embodiment C2, since the electricity storage device packaging films 211, 212 are not gas permeable, it is preferable to form a sub-chamber 214 for temporarily storing gas generated from the electricity storage device element 120 during the initial filling step or the like. For this reason, in the inner packaging step, the electricity storage device element 120 is wrapped in the electricity storage device packaging films 211, 212 that are larger than the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the completed electricity storage device 100. In the sub-chamber 214 of the electricity storage device packaging films 211, 212, a storage chamber 215 for storing more gas generated from the electricity storage device element 120 is formed.

The first inner sealing process of step S32 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 16, the portions of the periphery of the electricity storage device packaging films 211, 212 corresponding to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed so as to extend to the auxiliary chamber 214. Completion of the first inner sealing process forms an opening 213 in a portion 216 that faces the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed, across the auxiliary chamber 214. After the first inner sealing process, the vacuum drying process of step S33 is carried out.

The electrolyte injection process in step S34 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 16).

The second inner sealing step of step S35 is carried out after the electrolyte injection step. As shown in FIG. 17, in the second inner sealing step, the opening 213 is closed by sealing the portion 216 of the periphery of the packaging films 211, 212 for the electricity storage device, where the side seal portion 153 is to be formed, and the portion 216 facing the auxiliary chamber 214. After the second inner sealing step, the initial charge/discharge step of step S36 and the aging step of step S37 are carried out in sequence.

The degassing process in step S38 is carried out after the aging process. In the degassing process, gases such as carbon dioxide generated from the electricity storage device element 120 are temporarily stored in the auxiliary chamber 214 of the electricity storage device packaging films 211 and 212.

The auxiliary chamber removal process in step S39 is carried out after the degassing process. In the auxiliary chamber removal process, the auxiliary chamber 214 is removed by cutting the packaging films 211, 212 for the electricity storage device along the dashed line XA shown in Figure 17 so that the auxiliary chamber 214 is the same size as the inner packaging body 210 of the completed electricity storage device 100.

The inner sealing process of step S40 is carried out after the auxiliary chamber removal process. In the inner sealing process, as shown in FIG. 18, the portion of the periphery of the packaging films 211, 212 for the electricity storage device that corresponds to the side seal portion 153 is sealed. After the inner sealing process, the main charging process of step S41 is carried out.

The placement process of step S42 is carried out after this filling process. In the placement process, the functional object 230 is placed between the inner packaging body 210 and the outer packaging body 230 depending on the specific form of the functional object 230. When the functional object 230 is in the form of a sheet such as a film, the functional object 230 is, for example, wrapped around the inner packaging body 210 and joined to the inner packaging body 210. When the functional object 230 is a liquid that can be applied to a film or the like, the functional object 230 is applied to the surface of the inner packaging body 210 or the inner surface of the outer packaging body 220.

The outer packaging process in step S43 is carried out after the placement process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S44 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221, 222 is sealed to form the periphery seal portion 150. If the functional object 230 is in a granular or liquid form with a predetermined fluidity (viscosity), the placement process may be carried out in the outer sealing process, for example, by filling the opening in the portion where the bottom seal portion 154 is to be formed after the top seal portion 151, side seal portions 152, 153 of the periphery seal portion 150 are formed.

[Characteristics of the energy storage device]
According to the power storage device 100 of embodiment C3, since the functional object 230 is provided, the same effects as those of the power storage device 100 of embodiment C1 can be obtained.

[Embodiment C3]
The power storage device 300 of embodiment C3 differs from embodiment C1 in that the configuration of the terminal seal portion 151A is different, and other configurations are the same as those of embodiment C1. The following describes the power storage device 300 of embodiment C3, focusing on the differences from embodiment C1.

Figure 25 is a cross-sectional view of a terminal seal portion 351A provided in the electricity storage device 300 of embodiment C3. In the terminal seal portion 351A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to one tab film 140. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to one of the tab films 140. The flange portion 222A of the exterior film 222 is joined to the other tab film 140. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the power storage device 300, the inner packaging body 210 is covered by the outer packaging body 220, so that intrusion of moisture and the like from the outside into the internal space S1 of the inner packaging body 210 is suppressed.

[Embodiment C4]
The power storage device 400 of embodiment C4 differs from embodiment C in that the configuration of the terminal seal portion 151A is different, and other configurations are the same as those of embodiment C1. The following describes the power storage device 400 of embodiment C4, focusing on the differences from embodiment C1.

Figure 26 is a cross-sectional view of a terminal seal portion 451A provided in an electricity storage device 400 of embodiment C4. The electricity storage device 400 does not have a tab film 140. In the terminal seal portion 451A of the electricity storage device 400, from the top, an exterior film 221, a packaging film for the electricity storage device 211, a metal terminal 130, a packaging film for the electricity storage device 212, and an exterior film 222 are laminated and integrated.

The end 221X of the flange portion 221A is located closer to the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. The end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the power storage device. The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the power storage device. The end portion 222X of the flange portion 222A is located closer to the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end portion 222X of the flange portion 222A may be located in the same position as the end portion 212X of the packaging film 212 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device.

[Characteristics of the energy storage device]
According to the electricity storage device 400, the number of parts is reduced because the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140. In addition, the manufacturing method of the electricity storage device 400 can be simplified.

[Embodiment C5]
The power storage device 500 of embodiment C5 differs from embodiment C4 in that the configuration of the terminal seal portion 451A is different, and other configurations are the same as those of embodiment C4. The following describes the power storage device 500 of embodiment C5, focusing on the differences from embodiment C4.

Figure 27 is a cross-sectional view of a terminal seal portion 551A provided in the electricity storage device 500 of embodiment C5. In the terminal seal portion 551A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to the metal terminal 130. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the metal terminal 130.

The flange portion 221A of the exterior film 221 is joined to the metal terminal 130. The flange portion 222A of the exterior film 222 is joined to the metal terminal 130. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the electricity storage device 500, the inner packaging body 210 is covered by the outer packaging body 220, which prevents moisture and the like from entering the internal space S1 of the inner packaging body 210 from the outside. Moreover, according to the electricity storage device 500, the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140, which reduces the number of parts. Furthermore, the manufacturing method of the electricity storage device 500 can be simplified.

[Variations]
Each of the above-mentioned embodiments C is an example of a form that the power storage device and the manufacturing method of the power storage device according to the present disclosure can take, and is not intended to limit the form. The power storage device and the manufacturing method of the power storage device according to the present disclosure can take a form different from the form exemplified in each embodiment. One example is a form in which part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Below, several examples of modified forms of each embodiment are shown. Note that the following modified forms can be combined with each other as long as there is no technical contradiction.

In the energy storage device 100 of embodiment C1, the functional object 230 may be contained in at least one of the energy storage device packaging films 211, 212 or the exterior films 221, 222. That is, the energy storage device 100 of this modified example is configured such that at least one of the inner packaging body 210 and the outer packaging body 220 has at least one of shock absorption, flame retardancy, cooling properties, and fire extinguishing properties.

In the energy storage device 100 of embodiment C1, one outer packaging body 220 may be configured to house multiple inner packaging bodies 210 in a state in which the energy storage device elements 120 are housed. In this modification, the sizes of the multiple inner packaging bodies 210 may be different or the same. According to this modification, the multiple energy storage device elements 120 can be connected in series or parallel, so that the voltage can be easily adjusted.

In the energy storage device 100 of embodiment C1, the packaging films 211, 212 for the energy storage device do not have to be transparent or gas permeable.

In the energy storage device 100 of embodiment C1, the inner packaging body 210 may be constructed by folding one energy storage device packaging film 211 and heat sealing the peripheral portion. Similarly, the outer packaging body 220 may be constructed by folding one exterior film 221 and heat sealing the peripheral portion.

<Third aspect>
[Embodiment 1]
FIG. 8 shows a plan view of the power storage device 100 according to the first embodiment. FIG. 9 is a cross-sectional view taken along the line D2-D2 in FIG. 8. In FIG. 8, a portion that is not visible from the outside is partially shown by dotted lines for reference. Hereinafter, for convenience of explanation, unless otherwise specified, the up-down direction in FIG. 8 is referred to as the "front-rear direction", the left-right direction is referred to as the "left-right direction", and the up-down direction in FIG. 9 is referred to as the "up-down direction". However, the orientation of the power storage device 100 during use is not limited to this. In addition, in FIG. 8, the relative positional relationship between the inner wrapping body 210 and the outer wrapping body 220 is simplified for the sake of simplicity of the drawing.

The energy storage device 100 comprises a housing 110, an energy storage device element 120, a pair of metal terminals 130, and a pair of tab films 140. The housing 110 comprises an internal space S1 and a peripheral seal portion 150. The energy storage device element 120 is housed in the internal space S1 of the housing 110. One end of the metal terminal 130 is joined to the energy storage device element 120, and the other end protrudes outward from the peripheral seal portion 150 of the housing 110. A portion of the area between one end and the other end of the metal terminal 130 is fused to the peripheral seal portion 150 via the tab film 140.

The container 110 includes a container 110A. The container 110A includes an inner packaging body 210 and an outer packaging body 220. The inner packaging body 210 contains the power storage device element 120. The outer packaging body 220 contains the inner packaging body 210 in which the power storage device element 120 is contained. An internal space S1 is formed inside the inner packaging body 210. The inner packaging body 210 includes packaging films 211 and 212 for the power storage device. The outer packaging body 220 includes exterior films 221 and 222. In the outer peripheral portion of the container 110A in a plan view, the inner packaging body 210 and the outer packaging body 220 are heat-sealed and fused to each other, thereby forming a peripheral seal portion 150. The peripheral seal portion 150 forms an internal space S1 of the container 110A that is isolated from the external space in the inner packaging body 210. The peripheral seal portion 150 defines the periphery of the internal space S1 of the container 110A. The heat seal mode referred to here may be heat fusion from a heat source, ultrasonic fusion, or the like. In any case, the peripheral seal portion 150 refers to the portion where the inner wrapping body 210 and the outer wrapping body 220 are fused together to form an integrated unit.

The peripheral seal portion 150 includes a top seal portion 151, a pair of side seal portions 152, 153, and a bottom seal portion 154. The top seal portion 151 includes a portion that is sealed by sandwiching the metal terminal 130 and the tab film 140 (hereinafter referred to as "terminal seal portion 151A"), and extends in the front-rear direction. The pair of side seal portions 152, 153 extend in the left-right direction. The side seal portion 152 and the side seal portion 153 face each other across the internal space S1. The bottom seal portion 154 faces the top seal portion 151 across the internal space S1. The bottom seal portion 154 extends in the front-rear direction.

9, the terminal seal portion 151A of the top seal portion 151 is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. This makes it easy to form the top seal portion 151. Note that the portion of the top seal portion 151 other than the terminal seal portion 151A, in other words, the portion where only the pair of tab films 140 are sandwiched between the inner packaging body 210 and the outer packaging body 220, is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. Furthermore, the outer portion of the terminal seal portion 151A of the top seal portion 151 (the left portion with the step as the boundary in FIG. 9) is made up of, from the top, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, and the packaging film for the power storage device 212, which are laminated and integrated together. Therefore, there is a step between the outer portion of the terminal seal portion 151A where the exterior films 221, 222 are not present and the inner portion of the terminal seal portion 151A where the exterior films 221, 222 are present (the right portion with the step as the boundary in FIG. 9), but FIG. 8 shows an overview of the area of the peripheral seal portion 150, and does not show the step as the boundary.

The electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are transparent overall from the viewpoint of suitable manufacturing of the electricity storage device 100. Below, preferred examples of the electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are described. In the following, when there is no particular distinction between the electricity storage device packaging films 211, 212, the electricity storage device packaging films 211, 212 may be collectively referred to as the electricity storage device packaging film 10.

[Laminate structure and physical properties of the packaging film for electricity storage devices according to the third embodiment]
1 to 4, the packaging film 10 for an electricity storage device according to the third embodiment includes at least a heat-sealable resin layer 1. When assembling an electricity storage device using the packaging film 10 for an electricity storage device and an electricity storage device element, the heat-sealable resin layers 1 of the packaging film 10 for an electricity storage device are placed opposite each other, and the peripheral portions are heat-sealed to form a space in which the electricity storage device element is housed.

The packaging film 10 for the electricity storage device of the third embodiment may be composed only of the heat-sealable resin layer 1, as shown in FIG. 1. When the packaging film 10 for the electricity storage device is composed only of the heat-sealable resin layer 1, it is preferable that at least one surface of the heat-sealable resin layer 1 has adhesive properties to metal.

In addition, the packaging film 10 for an electricity storage device of the third embodiment is preferably composed of a laminate including at least a resin layer 2 and a heat-sealable resin layer 1, as shown in Figs. 2 to 4. In such a packaging film 10 for an electricity storage device, the resin layer 2 is on the outside, and the heat-sealable resin layer 1 is on the inside (the innermost layer). When the packaging film 10 for an electricity storage device is composed of a laminate including a resin layer 2 and the heat-sealable resin layer 1, it is preferable to impart adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1, and it is more preferable to impart adhesion to metal to the inner surface of the heat-sealable resin layer 1 that faces the metal terminal 130.

Furthermore, as shown in Figs. 3 and 4, the packaging film 10 for a power storage device of the third embodiment is preferably composed of a laminate including at least a resin layer 2, a substrate 3, and the heat-sealable resin layer 1. In such a packaging film 10 for a power storage device, the resin layer 2 is on the outside, the heat-sealable resin layer 1 is on the inside (the innermost layer), and the substrate 3 is located between the resin layer 2 and the heat-sealable resin layer 1. Even when the packaging film 10 for a power storage device is composed of a laminate including a resin layer 2, a substrate 3, and a heat-sealable resin layer 1, it is preferable to impart adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1, and it is more preferable to impart adhesion to metal to the inner surface of the heat-sealable resin layer 1 that faces the metal terminal 130.

As shown in FIG. 2, an adhesive layer 4 can be provided between the resin layer 2 and the heat-sealable resin layer 1, and as shown in FIG. 4, an adhesive layer 5 can be provided between the heat-sealable resin layer 1 and the substrate 3.

The packaging film 10 for electricity storage devices of the third embodiment preferably has a _CO2 permeation amount in an environment of 30°C of 100 cc·100 μm/ ^m2 /24 hr/atm or more, more preferably about 200 cc·100 μm/ ^m2 /24 hr/atm or more, even more preferably about 300 cc·100 μm/ ^m2 /24 hr/atm or more, and even more preferably about 500 cc·100 μm/ ^m2 /24 hr/atm or more. The _CO2 permeation amount of the packaging film 10 for an electricity storage device of the third embodiment is, for example, about 2000cc·100μm/ ^m2 /24hr/atm or less, preferably about 1000cc·100μm/ ^m2 /24hr/atm or less, and more preferably about 800cc·100μm/ ^m2 /24hr/atm or less, and preferred ranges are about 100 to 2000cc·100μm/ ^m2 /24hr/atm, about 100 to 1000cc·100μm/ ^m2 /24hr/atm, about 100 to 800cc·100μm/ ^m2 /24hr/atm, and about 200 to 2000cc·100μm/m2 ^. /24hr/atm, 200-1000cc・100μm/m ² /24hr/atm, 200-800cc・100μm/m ² /24hr/atm, 300-2000cc・100μm/m ² /24hr/atm approximately, 300-1000cc・100μm/m ² /24hr/atm approximately, 300-800cc・100μm/m ² /24hr/atm approximately, 500-2000cc・100μm/m ² /24hr/atm or so, 500-1000cc/100μm/m ² /24hr/atm or so, 500-800cc/100μm/ ^m2 The _CO2 permeation amount of the packaging film for an electricity storage device is measured by the following method.

[Measurement of _CO2 permeation amount]
In accordance with JIS K7126-1 (Plastics - Films and sheets - Gas permeability test method - Part 1: Differential pressure method), the amount of _CO2 that has permeated through a φ60 mm piece of the packaging film 10 for electricity storage devices in an atmosphere at 30°C is quantitatively analyzed by gas chromatography to measure the amount of CO2 permeated.

Although not shown in the figure, a surface coating layer or the like may be further provided on the outside of the resin layer 2 (the side opposite to the heat-sealable resin layer 1) as necessary.

The thickness of the laminate constituting the packaging film 10 for the third embodiment of the electric storage device is not particularly limited, but from the viewpoint of cost reduction and energy density improvement, for example, it is 190 μm or less, preferably about 180 μm or less, about 170 μm or less. From the viewpoint of maintaining the function of the packaging film for the electric storage device to protect the electric storage device element, the thickness of the laminate constituting the packaging film 10 for the electric storage device is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more. Preferred ranges of the laminate constituting the packaging film 10 for the electric storage device include, for example, about 35 to 190 μm, about 35 to 180 μm, about 35 to 170 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 170 μm, about 60 to 190 μm, about 60 to 180 μm, and about 60 to 170 μm, and in particular about 45 to 170 μm is preferred.

In the third embodiment of the packaging film 10 for a storage battery device, the ratio of the total thickness of the resin layer 2, adhesive layer 4, substrate 3, adhesive layer 5, and heat-sealable resin layer 1 to the thickness (total thickness) of the laminate constituting the packaging film 10 for a storage battery device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the packaging film 10 for a storage battery device of the third embodiment includes the resin layer 2, adhesive layer 4, substrate 3, adhesive layer 5, and heat-sealable resin layer 1, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging film 10 for a storage battery device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Also, even when the packaging film 10 for the electricity storage device of the third embodiment is a laminate including the resin layer 2, the adhesive layer 4, and the heat-sealable resin layer 1, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging film 10 for the electricity storage device can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

The laminate constituting the packaging film 10 for the third aspect of the storage battery device can have a total light transmittance measured in accordance with the provisions of JIS K7361-1:1997 of, for example, 80% or more, 85% or more, 90% or more. The lower the total light transmittance, the higher the shielding property of the packaging film 10 for the storage battery device. On the other hand, the higher the total light transmittance, the higher the light transmittance of the packaging film 10 for the storage battery device. Therefore, the desired transparency can be maintained by keeping the total light transmittance at a certain lower limit. The lower limit of the total light transmittance is 0%, and the upper limit is 100%. The total light transmittance of the packaging film for the storage battery device is measured in the visible light region (400 to 700 nm) in accordance with the measurement method prescribed in JIS K7361-1:1997 using a commercially available spectrophotometer (for example, a UV-visible near-infrared spectrophotometer V-670 manufactured by JASCO Corporation), and the average value is taken as the total light transmittance. The measurement conditions are as follows: a halogen lamp is used as the light source, UV/Vis bandwidth: 5.0 nm, scanning speed: 1000 nm/min, response: Medium, data acquisition interval: 1.0 nm.

The packaging film 10 for the electricity storage device of the third embodiment can be colored black and transparent by making it black-based. By making the packaging film 10 for the electricity storage device black-based, the packaging film 10 for the electricity storage device has a unique color that makes it highly distinctive and highly designed. In addition, in the manufacturing process of the electricity storage device, it becomes possible to grasp the position with a sensor with higher accuracy, and it becomes possible to transport the packaging film 10 for the electricity storage device and seal the electricity storage device elements more accurately. Furthermore, it is possible to unify the electricity storage device and other electrical equipment in a black color scheme, giving the product a sense of luxury.

<Layers Constituting the Packaging Film for Electricity Storage Devices of the Third Aspect>
Each layer constituting the packaging film for electricity storage devices of the third embodiment is the same as that of the packaging films for electricity storage devices of the first and second embodiments, and therefore description thereof will be omitted.

[Method for producing packaging film for electricity storage device according to third embodiment]
The method for producing the packaging film for an electricity storage device of the third embodiment is not particularly limited as long as the packaging film for an electricity storage device of the third embodiment can be obtained. For example, when the packaging film for an electricity storage device of the third embodiment includes a resin layer 2 and a heat-sealable resin layer 1, the method includes a step of producing a laminate in which at least a resin layer and a heat-sealable resin layer are laminated from the outside, and the laminate preferably has a _CO2 permeation amount of 100 cc·100 μm/ ^m2 /24 hr/atm or more in a temperature 30° C. environment.

An example of a manufacturing method in which the packaging film for an electricity storage device of the third embodiment is composed of a laminate having the resin layer 2, the adhesive layer 4, the substrate 3, the adhesive layer 5, and the heat-sealable resin layer 1 in this order is as follows. First, the materials constituting each layer are prepared. Next, the resin layer 2 and the substrate 3 are laminated via the adhesive layer 4, and the substrate 3 and the heat-sealable resin layer 1 are laminated via the adhesive layer 5. Specifically, the resin layer 2 and the substrate 3 are laminated by a dry lamination method or the like using an adhesive that forms the adhesive layer 4, so that the resin layer 2, the adhesive layer 4, and the substrate 3 are laminated, and further, the substrate 3 and the heat-sealable resin layer 1 are laminated by a dry lamination method or the like using an adhesive that forms the adhesive layer 5, thereby manufacturing the packaging film for an electricity storage device 10. In addition, when the resin layer 2, the substrate 3, and the heat-sealable resin layer 1 are laminated without the adhesive layers 4 and 5, the packaging film 10 for the electric storage device can be manufactured by melt-extruding the resin constituting the resin layer 2 onto one side of the substrate 3, and melt-extruding the resin constituting the heat-sealable resin layer 1 onto the other side of the substrate 3. When a colored layer is provided, the colored layer is formed on the surface of the resin layer 2, and then laminated with the substrate 3 and the heat-sealable resin layer 1. When a surface coating layer is provided, it can be formed, for example, by applying the above-mentioned resin composition for forming the surface coating layer onto the surface of the resin layer 2 and curing it.

To strengthen the adhesive properties of the adhesive layers 4 and 5, the packaging film 10 for the electricity storage device may be subjected to a heat treatment.

The shape of the inner packaging body 210 of the third embodiment is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided sealed type, a four-sided sealed type, a pillow type, a gusset type, or the like. The inner packaging body 210 of the first embodiment has a shape as shown in FIG. 2, and is manufactured by heat-sealing a packaging film for an electric storage device 212 formed into a tray shape and a packaging film for an electric storage device 211 also formed into a tray shape and superimposed on the packaging film for an electric storage device 212, along the outer periphery in a plan view. The packaging film for an electric storage device 212 includes a flange portion 212A of a square ring shape corresponding to the outer periphery in a plan view, and a molded portion 212B that is continuous with the inner edge of the flange portion 212A and bulges downward therefrom. Similarly, the electricity storage device packaging film 211 includes a rectangular ring-shaped flange portion 211A that corresponds to the outer periphery in a plan view, and a flange portion 211B that is continuous with the inner edge of the flange portion 211A and bulges upward from the flange portion 211A. The electricity storage device packaging films 211 and 212 are overlapped such that the respective molded portions 211B and 212B bulge in opposite directions. In this state, the flange portion 211A of the electricity storage device packaging film 211 and the flange portion 212A of the electricity storage device packaging film 212 are heat-sealed so as to be integrated, forming a part of the peripheral seal portion 150. Note that one of the electricity storage device packaging films 211 and 212 may be in the form of a sheet.

The exterior films 221, 222 constituting the outer packaging body 220 of the third embodiment are, for example, made of a resin molded product or film. The resin molded product referred to here can be manufactured by a method such as injection molding, compressed air molding, vacuum molding, blow molding, etc., and in-mold molding may be performed to impart design and functionality. The type of resin may be polyolefin, polyester, nylon, ABS, etc. Furthermore, the film referred to here is, for example, a resin film that can be manufactured by a method such as an inflation method or a T-die method, or a resin film laminated on a metal foil or metal plate. Furthermore, the film referred to here may be stretched or not, and may be a single-layer film or a multilayer film. Furthermore, the multilayer film referred to here may be manufactured by a coating method, may be a film in which multiple films are bonded with an adhesive, or may be manufactured by a multilayer extrusion method.

The exterior films 221 and 222 of the third aspect can be configured in various ways, but in this embodiment 1, they are composed of a laminate film. The laminate film can be a laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated. The base layer functions as a base material for the exterior films 221 and 222, and is typically an insulating resin layer that forms the outer layer side of the outer packaging body 220. The barrier layer not only improves the strength of the exterior films 221 and 222, but also has the function of preventing at least moisture and the like from penetrating into the power storage device 100, and is typically a metal layer made of aluminum alloy foil or the like. The heat-sealable resin layer is typically made of a heat-sealable resin such as polyolefin, and forms the innermost layer of the outer packaging body 220.

The shape of the outer packaging body 220 of the third aspect is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The container 110A of the present embodiment 1 has a shape as shown in FIG. 2, and is manufactured by heat-sealing an exterior film 222 formed into a tray shape and an exterior film 221 similarly formed into a tray shape and superimposed on the exterior film 222 along the outer periphery in a plan view. The exterior film 222 includes a square ring-shaped flange portion 222A corresponding to the outer periphery in a plan view, and a molded portion 222B that is continuous with the inner edge of the flange portion 222A and bulges downward therefrom. Similarly, the exterior film 221 includes a square ring-shaped flange portion 221A corresponding to the outer periphery in a plan view, and a flange portion 221B that is continuous with the inner edge of the flange portion 221A and bulges upward therefrom. The exterior films 221 and 222 are overlapped so that the respective molded portions 221B and 222B bulge in opposite directions. In this state, the flange portion 221A of the exterior film 221 and the flange portion 222A of the exterior film 222 are heat sealed to be integrated together, forming a part of the peripheral seal portion 150. Note that one of the exterior films 221 and 222 may be in the form of a sheet.

As shown in FIG. 2, in the terminal seal portion 151A, a portion of the flange portion 211A of the packaging film 211 for the power storage device is joined to one of the tab films 140. A portion of the flange portion 212A of the packaging film 212 for the power storage device is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 of the third embodiment is joined to the flange portion 211A of the packaging film 211 for the electricity storage device. The end 221X of the flange portion 221A is located closer to the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device.

The flange portion 222A of the exterior film 222 in the third embodiment is joined to the flange portion 212A of the packaging film 212 for the electricity storage device. The end 222X of the flange portion 222A is located closer to the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 222X of the flange portion 222A may be located in the same position as the end 212X of the packaging film 212 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device.

The third aspect of the power storage device element 120 has at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, a lithium ion battery (secondary battery) or a power storage member such as a capacitor.

The metal terminal 130 is a metal terminal used for inputting and outputting power to and from the power storage device element 120. The metal terminal 130 is arranged, for example, in the top seal portion 151 of the container 110A, with one terminal constituting a positive electrode side terminal and the other terminal constituting a negative electrode side terminal. One end in the left-right direction of each metal terminal 130 is electrically connected to an electrode (positive electrode or negative electrode) of the power storage device element 120 in the internal space S1 of the container 110A, and the other end protrudes outward from the peripheral seal portion 150. The above-mentioned form of the power storage device 100 is particularly preferable for use in electric vehicles such as electric vehicles and hybrid vehicles that use a large number of power storage devices 100 connected in series at high voltage. The mounting positions of the two metal terminals 130 that constitute the positive and negative electrode terminals are not particularly limited, and may be arranged, for example, in the side seal portions 152, 153 or bottom seal portion 154 of the peripheral seal portion 150.

The metal material constituting the metal terminal 130 is, for example, aluminum, nickel, copper, etc. When the power storage device element 120 is a lithium ion battery, the metal terminal 130 connected to the positive electrode is typically made of aluminum, etc., and the metal terminal 130 connected to the negative electrode is typically made of copper, nickel, etc.

The tab film 140 is a so-called adhesive film, and is configured to adhere to both the electricity storage device packaging films 211, 212 and the metal terminal 130. By using the tab film 140, the metal terminal 130 and the innermost layer (thermally adhesive resin layer) of the electricity storage device packaging films 211, 212 can be fixed together even if they are made of different materials. The tab film 140 is integrated by being fused and fixed to the metal terminal 130 in advance, and the electricity storage device packaging films 211, 212 are fused to the metal terminal 130 to which the tab film 140 is fixed.

[Method for manufacturing the electricity storage device according to the third embodiment]
10 is a flowchart showing an example of a method for manufacturing the power storage device 100. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging process of step S11, as shown in FIG. 11, the formed electricity storage device packaging films 211, 212 are wrapped around the electricity storage device element 120. In the electricity storage device 100 of the first embodiment, the electricity storage device packaging films 211, 212 are gas permeable, so there is no need to form a sub-chamber for temporarily storing the gas generated from the electricity storage device element 120 in the initial filling process described below. Therefore, in the inner packaging process, the electricity storage device element 120 is wrapped around the electricity storage device packaging films 211, 212 that are substantially the same size as the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the finished electricity storage device 100. This simplifies the manufacturing process of the electricity storage device 100. In addition, the amount of material used for the electricity storage device 100 can be reduced. "Substantially the same size" includes cases where the size is larger than the electricity storage device packaging films 211, 212 included in the inner packaging body 210 of the finished electricity storage device 100 to the extent that a sub-chamber cannot be formed. Note that the electricity storage device element 120 is connected to the metal terminal 130 in advance, and the tab film 140 is joined to the metal terminal 130.

The first inner sealing process in step S12 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 12, the portions of the periphery of the electricity storage device packaging films 211, 212 that correspond to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed. Completion of the first inner sealing process forms an opening 213 in the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed. After the first inner sealing process, the vacuum drying process in step S13 is carried out.

The electrolyte injection process in step S14 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 12).

The second inner sealing process in step S15 is carried out after the electrolyte injection process. As shown in FIG. 13, in the second inner sealing process, the opening 213 is closed by sealing the portion of the periphery of the packaging films 211, 212 for the electricity storage device where the side seal portion 153 is to be formed. After the second inner sealing process, the initial charge/discharge process in step S16 and the aging process in step S17 are carried out in order.

The degassing process in step S18 is carried out in parallel with the initial charge/discharge process and the aging process. In this embodiment 1, the packaging films 211 and 212 for the electricity storage device are gas permeable, so that gases such as carbon dioxide generated from the electricity storage device element 120 during the initial charge/discharge process and the aging process are discharged to the outside through the packaging films 211 and 212 for the electricity storage device. After the degassing process, the main charging process in step S19 is carried out.

The outer packaging process in step S20 is carried out after the main charging process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S21 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221 and 222 is sealed to form the periphery seal portion 150.

[Characteristics of the electricity storage device according to the third embodiment]
According to the electricity storage device 100, since the electricity storage device packaging films 211 and 212 have transparency, after the first inner sealing step or the second inner sealing step is completed, it is possible to easily check whether the electricity storage device packaging film 211 and the electricity storage device packaging film 212 are properly sealed. Therefore, the electricity storage device 100 can be suitably manufactured. The state in which the electricity storage device packaging film 211 and the electricity storage device packaging film 212 are not properly sealed includes, for example, a first state, a second state, or a third state. The first state is a state in which the electricity storage device packaging film 211 and the electricity storage device packaging film 212 are sealed with a foreign object caught between them. The second state is a state in which a part of the part that should be sealed is not sealed. The third state is a state in which a part that should not be sealed is sealed.

[Embodiment 2 of the third aspect]
The electricity storage device 100 of the second embodiment differs from the first embodiment in that the electricity storage device packaging films 211, 212 are not gas permeable, or in that, compared to the first embodiment, they do not have gas permeability to the extent that the degassing step of step S18 described above is performed, but the other configurations are similar to those of the first embodiment. The electricity storage device 100 of the second embodiment will be described below, focusing on the differences from the second embodiment.

[Method of manufacturing electricity storage device]
14 is a flowchart illustrating an example of a method for manufacturing the power storage device 100 according to the second embodiment. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging step of step S31, as shown in FIG. 15, the formed electricity storage device packaging films 211, 212 are used to wrap the electricity storage device element 120. In the electricity storage device 100 of the second embodiment, since the electricity storage device packaging films 211, 212 are not gas permeable, it is preferable to form a sub-chamber 214 for temporarily storing gas generated from the electricity storage device element 120 during the initial filling step or the like. For this reason, in the inner packaging step, the electricity storage device element 120 is wrapped in the electricity storage device packaging films 211, 212 that are larger than the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the completed electricity storage device 100. In the sub-chamber 214 of the electricity storage device packaging films 211, 212, a storage chamber 215 for storing more gas generated from the electricity storage device element 120 is formed.

The first inner sealing process of step S32 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 16, the portions of the periphery of the electricity storage device packaging films 211, 212 corresponding to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed so as to extend to the auxiliary chamber 214. Completion of the first inner sealing process forms an opening 213 in a portion 216 that faces the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed, across the auxiliary chamber 214. After the first inner sealing process, the vacuum drying process of step S33 is carried out.

The electrolyte injection process in step S34 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 16).

The second inner sealing step of step S35 is carried out after the electrolyte injection step. As shown in FIG. 17, in the second inner sealing step, the opening 213 is closed by sealing the portion 216 of the periphery of the packaging films 211, 212 for the electricity storage device, where the side seal portion 153 is to be formed, and the portion 216 facing the auxiliary chamber 214. After the second inner sealing step, the initial charge/discharge step of step S36 and the aging step of step S37 are carried out in sequence.

The degassing process in step S38 is carried out after the aging process. In the degassing process, gases such as carbon dioxide generated from the electricity storage device element 120 are temporarily stored in the auxiliary chamber 214 of the electricity storage device packaging films 211 and 212.

The auxiliary chamber removal process in step S39 is carried out after the degassing process. In the auxiliary chamber removal process, the auxiliary chamber 214 is removed by cutting the packaging films 211, 212 for the electricity storage device along the dashed line XA shown in Figure 17 so that the auxiliary chamber 214 is the same size as the inner packaging body 210 of the completed electricity storage device 100.

The inner sealing process of step S40 is carried out after the auxiliary chamber removal process. In the inner sealing process, as shown in FIG. 18, the portion of the periphery of the packaging films 211, 212 for the electricity storage device that corresponds to the side seal portion 153 is sealed. After the inner sealing process, the main charging process of step S41 is carried out.

The outer packaging process in step S42 is carried out after the main charging process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S43 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221 and 222 is sealed to form the periphery seal portion 150.

[Characteristics of the energy storage device]
According to the electricity storage device 100 of the third embodiment, since the electricity storage device packaging films 211 and 212 have transparency, the same effects as those of the electricity storage device 100 of the first embodiment can be obtained.

[Embodiment 3 of the third aspect]
The power storage device 300 of the third embodiment differs from the first embodiment in that the configuration of the terminal seal portion 151A is different, but the other configurations are similar to those of the first embodiment. The following describes the power storage device 300 of the third embodiment, focusing on the differences from the first embodiment.

Figure 19 is a cross-sectional view of a terminal seal portion 351A provided in an electricity storage device 300 of embodiment 3. In the terminal seal portion 351A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to one tab film 140. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to one of the tab films 140. The flange portion 222A of the exterior film 222 is joined to the other tab film 140. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the power storage device 300, the inner packaging body 210 is covered by the outer packaging body 220, so that intrusion of moisture and the like from the outside into the internal space S1 of the inner packaging body 210 is suppressed.

[Embodiment 4 of the third aspect]
The power storage device 400 of the fourth embodiment differs from the first embodiment in that the configuration of the terminal seal portion 151A is different, but the other configurations are the same as those of the first embodiment. The following describes the power storage device 400 of the fourth embodiment, focusing on the differences from the first embodiment.

Figure 20 is a cross-sectional view of a terminal seal portion 451A provided in an electricity storage device 400 of embodiment 4. The electricity storage device 400 does not have a tab film 140. In the terminal seal portion 451A of the electricity storage device 400, from the top, an exterior film 221, a packaging film for the electricity storage device 211, a metal terminal 130, a packaging film for the electricity storage device 212, and an exterior film 222 are laminated and integrated.

The end 221X of the flange portion 221A is located closer to the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. The end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the power storage device. The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the power storage device. The end portion 222X of the flange portion 222A is located closer to the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end portion 222X of the flange portion 222A may be located in the same position as the end portion 212X of the packaging film 212 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device.

[Characteristics of the energy storage device]
According to the electricity storage device 400, the number of parts is reduced because the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140. In addition, the manufacturing method of the electricity storage device 400 can be simplified.

[Embodiment 5 of the third aspect]
The power storage device 500 of the fifth embodiment differs from the fourth embodiment in that the configuration of the terminal seal portion 451A is different, and the other configurations are the same as those of the fourth embodiment. The following describes the power storage device 500 of the fifth embodiment, focusing on the differences from the fourth embodiment.

Figure 21 is a cross-sectional view of a terminal seal portion 551A provided in an electricity storage device 500 of embodiment 5. In the terminal seal portion 551A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to the metal terminal 130. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the metal terminal 130.

The flange portion 221A of the exterior film 221 is joined to the metal terminal 130. The flange portion 222A of the exterior film 222 is joined to the metal terminal 130. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the electricity storage device 500, the inner packaging body 210 is covered by the outer packaging body 220, which prevents moisture and the like from entering the internal space S1 of the inner packaging body 210 from the outside. Moreover, according to the electricity storage device 500, the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140, which reduces the number of parts. Furthermore, the manufacturing method of the electricity storage device 500 can be simplified.

[Modification of the third embodiment]
Each embodiment of the third aspect is an example of a form that the power storage device and the manufacturing method of the power storage device according to the present disclosure can take, and is not intended to limit the form. The power storage device and the manufacturing method of the power storage device according to the present disclosure can take a form different from the form exemplified in each embodiment. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Some examples of modified examples of each embodiment are shown below. Note that the following modified examples can be combined with each other as long as there is no technical contradiction.

In the energy storage device 100 of the first embodiment of the third aspect, one outer packaging body 220 may be configured to house multiple inner packaging bodies 210 in a state in which the energy storage device elements 120 are housed. In this modification, the sizes of the multiple inner packaging bodies 210 may be different or the same. According to this modification, the multiple energy storage device elements 120 can be connected in series or parallel, so that the voltage can be easily adjusted.

In the electricity storage device 100 of the third aspect of the first embodiment, the packaging films 211 and 212 for the electricity storage device do not need to be gas permeable. The packaging films 211 and 212 for the electricity storage device only need to be transparent.

In the energy storage device 100 of the first embodiment of the third aspect, the inner packaging body 210 may be constructed by folding one energy storage device packaging film 211 and heat sealing the peripheral portion. Similarly, the outer packaging body 220 may be constructed by folding one exterior film 221 and heat sealing the peripheral portion.

<Fourth aspect>
[Embodiment 1]
FIG. 8 shows a plan view of the electric storage device 100 according to the first embodiment of the fourth aspect. FIG. 9 is a cross-sectional view taken along the line D2-D2 in FIG. 8. In FIG. 8, a portion that is not visible from the outside is partially shown by dotted lines for reference. In the following, for convenience of explanation, unless otherwise specified, the up-down direction in FIG. 8 is referred to as the "front-rear direction", the left-right direction is referred to as the "left-right direction", and the up-down direction in FIG. 9 is referred to as the "up-down direction". However, the orientation of the electric storage device 100 during use is not limited to this. In addition, in FIG. 8, the relative positional relationship between the inner wrapping body 210 and the outer wrapping body 220 is simplified for the sake of simplicity of the drawing.

The fourth aspect of the energy storage device 100 includes a housing 110, an energy storage device element 120, a pair of metal terminals 130, and a pair of tab films 140. The housing 110 includes an internal space S1 and a peripheral seal portion 150. The energy storage device element 120 is housed in the internal space S1 of the housing 110. One end of the metal terminal 130 is joined to the energy storage device element 120, and the other end protrudes outward from the peripheral seal portion 150 of the housing 110. A portion of the area between one end and the other end of the metal terminal 130 is fused to the peripheral seal portion 150 via the tab film 140.

The container 110 includes a container 110A. The container 110A includes an inner packaging body 210 and an outer packaging body 220. The inner packaging body 210 contains the power storage device element 120. The outer packaging body 220 contains the inner packaging body 210 in which the power storage device element 120 is contained. An internal space S1 is formed inside the inner packaging body 210. The inner packaging body 210 includes packaging films 211 and 212 for the power storage device. The outer packaging body 220 includes exterior films 221 and 222. In the outer peripheral portion of the container 110A in a plan view, the inner packaging body 210 and the outer packaging body 220 are heat-sealed and fused to each other, thereby forming a peripheral seal portion 150. The peripheral seal portion 150 forms an internal space S1 of the container 110A that is isolated from the external space in the inner packaging body 210. The peripheral seal portion 150 defines the periphery of the internal space S1 of the container 110A. The heat seal mode referred to here may be heat fusion from a heat source, ultrasonic fusion, or the like. In any case, the peripheral seal portion 150 refers to the portion where the inner wrapping body 210 and the outer wrapping body 220 are fused together to form an integrated unit.

The peripheral seal portion 150 includes a top seal portion 151, a pair of side seal portions 152, 153, and a bottom seal portion 154. The top seal portion 151 includes a portion that is sealed by sandwiching the metal terminal 130 and the tab film 140 (hereinafter referred to as "terminal seal portion 151A"), and extends in the front-rear direction. The pair of side seal portions 152, 153 extend in the left-right direction. The side seal portion 152 and the side seal portion 153 face each other across the internal space S1. The bottom seal portion 154 faces the top seal portion 151 across the internal space S1. The bottom seal portion 154 extends in the front-rear direction.

9, the terminal seal portion 151A of the top seal portion 151 is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. This makes it easy to form the top seal portion 151. Note that the portion of the top seal portion 151 other than the terminal seal portion 151A, in other words, the portion where only the pair of tab films 140 are sandwiched between the inner packaging body 210 and the outer packaging body 220, is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. Furthermore, the outer portion of the terminal seal portion 151A of the top seal portion 151 (the left portion with the step as the boundary in FIG. 9) is made up of, from the top, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, and the packaging film for the power storage device 212, which are laminated and integrated together. Therefore, there is a step between the outer portion of the terminal seal portion 151A where the exterior films 221, 222 are not present and the inner portion of the terminal seal portion 151A where the exterior films 221, 222 are present (the right portion with the step as the boundary in FIG. 9), but FIG. 8 shows an overview of the area of the peripheral seal portion 150, and does not show the step as the boundary.

The electricity storage device packaging films 211, 212 constituting the inner packaging body 210 have gas permeability from the viewpoint of easily manufacturing the electricity storage device 100. Below, preferred examples of the electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are described. In the following, when there is no particular distinction between the electricity storage device packaging films 211, 212, the electricity storage device packaging films 211, 212 may be collectively referred to as the electricity storage device packaging film 10.

[Laminate structure and physical properties of the packaging film for electricity storage devices according to the fourth embodiment]
1 to 4, the packaging film 10 for an electricity storage device according to the fourth embodiment includes at least a heat-sealable resin layer 1. When assembling an electricity storage device using the packaging film 10 for an electricity storage device and an electricity storage device element, the heat-sealable resin layers 1 of the packaging film 10 for an electricity storage device are placed opposite each other, and the peripheral portions are heat-sealed to form a space in which the electricity storage device element is housed.

The packaging film 10 for the electricity storage device of the fourth embodiment may be composed only of the heat-sealable resin layer 1, as shown in FIG. 1. When the packaging film 10 for the electricity storage device is composed only of the heat-sealable resin layer 1, it is preferable that at least one surface of the heat-sealable resin layer 1 has adhesive properties to metal, and it is more preferable that the inner surface of the heat-sealable resin layer 1 facing the metal terminal 130 has adhesive properties to metal.

In addition, the fourth embodiment of the packaging film 10 for an electricity storage device is preferably composed of a laminate including at least a resin layer 2 and a heat-sealable resin layer 1, as shown in Figs. 2 to 4. In such a packaging film 10 for an electricity storage device, the resin layer 2 is on the outside, and the heat-sealable resin layer 1 is on the inside (the innermost layer). When the packaging film 10 for an electricity storage device is composed of a laminate including a resin layer 2 and the heat-sealable resin layer 1, it is preferable to impart adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1, and it is more preferable to impart adhesion to metal to the inner surface of the heat-sealable resin layer 1 that faces the metal terminal 130.

Furthermore, as shown in Figs. 3 and 4, the packaging film 10 for a storage battery device in the fourth embodiment is preferably composed of a laminate including at least a resin layer 2, a substrate 3, and the heat-sealable resin layer 1. In such a packaging film 10 for a storage battery device, the resin layer 2 is on the outside, the heat-sealable resin layer 1 is on the inside (the innermost layer), and the substrate 3 is located between the resin layer 2 and the heat-sealable resin layer 1. Even when the packaging film 10 for a storage battery device is composed of a laminate including a resin layer 2, a substrate 3, and a heat-sealable resin layer 1, it is preferable to impart adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1.

As shown in FIG. 2, an adhesive layer 4 can be provided between the resin layer 2 and the heat-sealable resin layer 1, and as shown in FIG. 4, an adhesive layer 5 can be provided between the heat-sealable resin layer 1 and the substrate 3.

The packaging film 10 for electricity storage devices of the fourth embodiment preferably has a _CO2 permeation amount in an environment of 30°C of 100 cc·100 μm/ ^m2 /24 hr/atm or more, more preferably about 200 cc·100 μm/ ^m2 /24 hr/atm or more, even more preferably about 300 cc·100 μm/ ^m2 /24 hr/atm or more, and even more preferably about 500 cc·100 μm/ ^m2 /24 hr/atm or more. The _CO2 permeation amount of the packaging film 10 for an electricity storage device of the fourth embodiment is, for example, about 2000cc·100μm/ ^m2 /24hr/atm or less, preferably about 1000cc·100μm/ ^m2 /24hr/atm or less, and more preferably about 800cc·100μm/ ^m2 /24hr/atm or less, and preferred ranges are about 100 to 2000cc·100μm/ ^m2 /24hr/atm, about 100 to 1000cc·100μm/ ^m2 /24hr/atm, about 100 to 800cc·100μm/ ^m2 /24hr/atm, and about 200 to 2000cc·100μm/m2 ^. /24hr/atm, 200-1000cc・100μm/m ² /24hr/atm, 200-800cc・100μm/m ² /24hr/atm, 300-2000cc・100μm/m ² /24hr/atm approximately, 300-1000cc・100μm/m ² /24hr/atm approximately, 300-800cc・100μm/m ² /24hr/atm approximately, 500-2000cc・100μm/m ² /24hr/atm or so, 500-1000cc/100μm/m ² /24hr/atm or so, 500-800cc/100μm/ ^m2 The _CO2 permeation amount of the packaging film for an electricity storage device is measured by the following method.

[Measurement of _CO2 permeation amount]
In accordance with JIS K7126-1 (Plastics - Films and sheets - Gas permeability test method - Part 1: Differential pressure method), the amount of _CO2 that has permeated through a φ60 mm piece of the packaging film 10 for electricity storage devices in an atmosphere at 30°C is quantitatively analyzed by gas chromatography to measure the amount of CO2 permeated.

When imparting shielding properties to the packaging film 10 for an electricity storage device of the fourth embodiment, at least one layer included in the packaging film 10 for an electricity storage device may be a shielding layer S having shielding properties. For example, FIG. 2 illustrates a configuration in which the adhesive layer 4 that bonds between the resin layer 2 and the heat-sealable resin layer 1 is the shielding layer S, and FIG. 4 illustrates a configuration in which the adhesive layer 4 that bonds between the resin layer 2 and the substrate 3 is the shielding layer S. In the fourth embodiment, any layer included in the packaging film 10 for an electricity storage device may be the shielding layer S.

Although not shown in the figure, a surface coating layer or the like may be further provided on the outside of the resin layer 2 (the side opposite to the heat-sealable resin layer 1) as necessary.

The thickness of the laminate constituting the packaging film 10 for the electric storage device of the fourth embodiment is not particularly limited, but from the viewpoint of cost reduction, energy density improvement, etc., it is, for example, 190 μm or less, preferably about 180 μm or less, about 170 μm or less. From the viewpoint of maintaining the function of the packaging film for the electric storage device to protect the electric storage device element, the thickness of the laminate constituting the packaging film 10 for the electric storage device is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more. Preferred ranges of the laminate constituting the packaging film 10 for the electric storage device include, for example, about 35 to 190 μm, about 35 to 180 μm, about 35 to 170 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 170 μm, about 60 to 190 μm, about 60 to 180 μm, and about 60 to 170 μm, and about 45 to 170 μm is particularly preferred.

In the fourth embodiment of the packaging film 10 for a storage battery device, the ratio of the total thickness of the resin layer 2, adhesive layer 4, substrate 3, adhesive layer 5, and heat-sealable resin layer 1 to the thickness (total thickness) of the laminate constituting the packaging film 10 for a storage battery device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the packaging film 10 for a storage battery device of the fourth embodiment includes the resin layer 2, adhesive layer 4, substrate 3, adhesive layer 5, and heat-sealable resin layer 1, the ratio of the total thickness of each of these layers to the thickness (total thickness) of the laminate constituting the packaging film 10 for a storage battery device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Also, even when the fourth embodiment of the packaging film 10 for an electricity storage device is a laminate including a resin layer 2, an adhesive layer 4, and a heat-sealable resin layer 1, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging film 10 for an electricity storage device can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

The laminate constituting the packaging film 10 for the electric storage device of the fourth aspect can have a total light transmittance measured in accordance with the provisions of JIS K7361-1:1997 of, for example, 20% or less, 15% or less, 10% or less, 8% or less, etc. The laminate constituting the packaging film 10 for the electric storage device of the fourth aspect can have a total light transmittance measured in accordance with the provisions of JIS K7361-1:1997 of, for example, 80% or more, 85% or more, 90% or more, etc. The lower the total light transmittance, the higher the shielding property of the packaging film 10 for the electric storage device. On the other hand, the higher the total light transmittance, the higher the light transmittance of the packaging film 10 for the electric storage device. The lower limit of the total light transmittance is 0%, and the upper limit is 100%. The total light transmittance of the packaging film for power storage devices is measured in accordance with the measurement method specified in JIS K7361-1:1997 using a commercially available spectrophotometer (for example, JASCO's UV-Vis-Near-Infrared Spectrophotometer V-670) in the visible light region (400-700 nm), and the average value is taken as the total light transmittance. The measurement conditions are as follows: a halogen lamp is used as the light source, UV/Vis bandwidth: 5.0 nm, scanning speed: 1000 nm/min, response: Medium, data acquisition interval: 1.0 nm.

The fourth aspect of the packaging film 10 for the electricity storage device can be black. When the packaging film 10 for the electricity storage device is black, the packaging film 10 for the electricity storage device has high shielding properties and is highly effective in preventing counterfeiting. In addition, during the manufacturing process of the electricity storage device, it becomes possible to grasp the position with a sensor with higher accuracy, and it becomes possible to transport the packaging film 10 for the electricity storage device and seal the electricity storage device elements more accurately. Furthermore, it is possible to unify the electricity storage device and other electrical equipment in black, giving the product a sense of luxury.

<Layers Constituting the Packaging Film for Electricity Storage Devices of the Fourth Aspect>
Each layer constituting the packaging film for electricity storage devices of the fourth embodiment is the same as that of the packaging films for electricity storage devices of the first and second embodiments, and therefore description thereof will be omitted.

[Method for producing packaging film for electricity storage device according to the fourth embodiment]
The method for producing the packaging film for an electricity storage device is not particularly limited as long as the packaging film for an electricity storage device of the fourth embodiment can be obtained. For example, when the packaging film for an electricity storage device of the fourth embodiment includes a resin layer 2 and a heat-sealable resin layer 1, the method includes a step of producing a laminate in which at least a resin layer and a heat-sealable resin layer are laminated from the outside, and the laminate preferably has a _CO2 permeation amount of 100 cc·100 μm/ ^m2 /24 hr/atm or more in a temperature 30° C. environment.

An example of a manufacturing method in which the packaging film for an electricity storage device of the fourth aspect is composed of a laminate having the resin layer 2, the adhesive layer 4, the substrate 3, the adhesive layer 5, and the heat-sealable resin layer 1 in this order is as follows. First, the materials constituting each layer are prepared. Next, the resin layer 2 and the substrate 3 are laminated via the adhesive layer 4, and the substrate 3 and the heat-sealable resin layer 1 are laminated via the adhesive layer 5. Specifically, the resin layer 2 and the substrate 3 are laminated by a dry lamination method or the like using an adhesive that forms the adhesive layer 4, so that the resin layer 2, the adhesive layer 4, and the substrate 3 are laminated, and further, the substrate 3 and the heat-sealable resin layer 1 are laminated by a dry lamination method or the like using an adhesive that forms the adhesive layer 5, thereby manufacturing the packaging film for an electricity storage device 10. In addition, when the resin layer 2, the substrate 3, and the heat-sealable resin layer 1 are laminated without the adhesive layers 4 and 5, the packaging film 10 for the electric storage device can be manufactured by melt-extruding the resin constituting the resin layer 2 onto one side of the substrate 3, and melt-extruding the resin constituting the heat-sealable resin layer 1 onto the other side of the substrate 3. When a colored layer is provided, the colored layer is formed on the surface of the resin layer 2, and then laminated with the substrate 3 and the heat-sealable resin layer 1. When a surface coating layer is provided, it can be formed, for example, by applying the above-mentioned resin composition for forming the surface coating layer onto the surface of the resin layer 2 and curing it.

To strengthen the adhesive properties of the adhesive layers 4 and 5, the packaging film 10 for the electricity storage device may be subjected to a heat treatment.

The shape of the inner packaging body 210 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The inner packaging body 210 of the present embodiment 1 has a shape as shown in FIG. 9, and is manufactured by heat-sealing the packaging film for the power storage device 212 formed into a tray shape and the packaging film for the power storage device 211 formed into a tray shape and superimposed on the packaging film for the power storage device 212 along the outer periphery in a plan view. The packaging film for the power storage device 212 includes a flange portion 212A of a square ring shape corresponding to the outer periphery in a plan view, and a molded portion 212B that is continuous with the inner edge of the flange portion 212A and bulges downward therefrom. Similarly, the packaging film for the power storage device 211 includes a flange portion 211A of a square ring shape corresponding to the outer periphery in a plan view, and a flange portion 211B that is continuous with the inner edge of the flange portion 211A and bulges upward therefrom. The electricity storage device packaging films 211, 212 are overlapped so that the respective molded portions 211B, 212B bulge in opposite directions. In this state, the flange portion 211A of the electricity storage device packaging film 211 and the flange portion 212A of the electricity storage device packaging film 212 are heat sealed to be integrated together, forming part of the peripheral seal portion 150. Note that one of the electricity storage device packaging films 211, 212 may be in the form of a sheet.

The exterior films 221, 222 constituting the outer packaging body 220 are, for example, made of a resin molded product or film. The resin molded product referred to here can be manufactured by injection molding, compressed air molding, vacuum molding, blow molding, or other methods, and in-mold molding may be used to impart design and functionality. The type of resin may be polyolefin, polyester, nylon, ABS, or other materials. The film referred to here is, for example, a resin film that can be manufactured by an inflation method or a T-die method, or a resin film laminated on a metal foil or metal plate. The film referred to here may or may not be stretched, and may be a single-layer film or a multilayer film. The multilayer film referred to here may be manufactured by a coating method, may be a film in which multiple films are bonded together with an adhesive, or may be manufactured by a multilayer extrusion method.

The exterior films 221 and 222 can be configured in various ways, but in this embodiment 1, they are composed of a laminate film. The laminate film can be a laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated. The base layer functions as a base material for the exterior films 221 and 222, and is typically an insulating resin layer that forms the outer layer side of the outer packaging body 220. The barrier layer has a function of preventing at least moisture and the like from penetrating into the power storage device 100 in addition to improving the strength of the exterior films 221 and 222, and is typically a metal layer made of aluminum alloy foil or the like. The heat-sealable resin layer is typically made of a heat-sealable resin such as polyolefin, and forms the innermost layer of the outer packaging body 220.

The shape of the outer packaging body 220 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The container 110A of the present embodiment 1 has a shape as shown in FIG. 9, and is manufactured by heat-sealing an exterior film 222 formed into a tray shape and an exterior film 221 similarly formed into a tray shape and superimposed on the exterior film 222 along the outer periphery in a plan view. The exterior film 222 includes a square ring-shaped flange portion 222A corresponding to the outer periphery in a plan view, and a molded portion 222B that is continuous with the inner edge of the flange portion 222A and bulges downward therefrom. Similarly, the exterior film 221 includes a square ring-shaped flange portion 221A corresponding to the outer periphery in a plan view, and a flange portion 221B that is continuous with the inner edge of the flange portion 221A and bulges upward therefrom. The exterior films 221 and 222 are overlapped so that the respective molded portions 221B and 222B bulge in opposite directions. In this state, the flange portion 221A of the exterior film 221 and the flange portion 222A of the exterior film 222 are heat sealed to be integrated together, forming a part of the peripheral seal portion 150. Note that one of the exterior films 221 and 222 may be in the form of a sheet.

As shown in FIG. 9, in the terminal seal portion 151A, a portion of the flange portion 211A of the packaging film 211 for the power storage device is joined to one of the tab films 140. A portion of the flange portion 212A of the packaging film 212 for the power storage device is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the electricity storage device. The end 221X of the flange portion 221A is located closer to the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device.

The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the electricity storage device. The end 222X of the flange portion 222A is located closer to the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 222X of the flange portion 222A may be located in the same position as the end 212X of the packaging film 212 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device.

The power storage device element 120 has at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, a lithium ion battery (secondary battery) or a power storage member such as a capacitor.

The metal terminal 130 is a metal terminal used for inputting and outputting power to and from the power storage device element 120. The metal terminal 130 is arranged, for example, in the top seal portion 151 of the container 110A, with one terminal constituting a positive electrode side terminal and the other terminal constituting a negative electrode side terminal. One end in the left-right direction of each metal terminal 130 is electrically connected to an electrode (positive electrode or negative electrode) of the power storage device element 120 in the internal space S1 of the container 110A, and the other end protrudes outward from the peripheral seal portion 150. The above-mentioned form of the power storage device 100 is particularly preferable for use in electric vehicles such as electric vehicles and hybrid vehicles that use a large number of power storage devices 100 connected in series at high voltage. The mounting positions of the two metal terminals 130 that constitute the positive and negative electrode terminals are not particularly limited, and may be arranged, for example, in the side seal portions 152, 153 or bottom seal portion 154 of the peripheral seal portion 150.

The metal material constituting the metal terminal 130 is, for example, aluminum, nickel, copper, etc. When the power storage device element 120 is a lithium ion battery, the metal terminal 130 connected to the positive electrode is typically made of aluminum, etc., and the metal terminal 130 connected to the negative electrode is typically made of copper, nickel, etc.

The tab film 140 is a so-called adhesive film, and is configured to adhere to both the electricity storage device packaging films 211, 212 and the metal terminal 130. By using the tab film 140, the metal terminal 130 and the innermost layer (thermally adhesive resin layer) of the electricity storage device packaging films 211, 212 can be fixed together even if they are made of different materials. The tab film 140 is integrated by being fused and fixed to the metal terminal 130 in advance, and the electricity storage device packaging films 211, 212 are fused to the metal terminal 130 to which the tab film 140 is fixed.

[Method for manufacturing the electricity storage device according to the fourth embodiment]
10 is a flowchart showing an example of a method for manufacturing the power storage device 100. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging process of step S11, as shown in FIG. 11, the formed electricity storage device packaging films 211, 212 are wrapped around the electricity storage device element 120. In the electricity storage device 100 of the first embodiment, the electricity storage device packaging films 211, 212 are gas permeable, so there is no need to form a sub-chamber for temporarily storing the gas generated from the electricity storage device element 120 in the initial filling process described below. Therefore, in the inner packaging process, the electricity storage device element 120 is wrapped around the electricity storage device packaging films 211, 212 that are substantially the same size as the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the finished electricity storage device 100. This simplifies the manufacturing process of the electricity storage device 100. In addition, the amount of material used for the electricity storage device 100 can be reduced. "Substantially the same size" includes cases where the size is larger than the electricity storage device packaging films 211, 212 included in the inner packaging body 210 of the finished electricity storage device 100 to the extent that a sub-chamber cannot be formed. Note that the electricity storage device element 120 is connected to the metal terminal 130 in advance, and the tab film 140 is joined to the metal terminal 130.

The first inner sealing process in step S12 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 12, the portions of the periphery of the electricity storage device packaging films 211, 212 that correspond to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed. Completion of the first inner sealing process forms an opening 213 in the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed. After the first inner sealing process, the vacuum drying process in step S13 is carried out.

The electrolyte injection process in step S14 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 12).

The second inner sealing process of step S15 is performed after the electrolyte injection process. As shown in FIG. 13, in the second inner sealing process, the opening 213 is closed by sealing the portion of the periphery of the packaging films 211 and 212 for the electricity storage device where the side seal portion 153 is to be formed. According to the electricity storage device 100, since the packaging films 211 and 212 for the electricity storage device have transparency, it is easy to check whether the packaging films 211 and 212 for the electricity storage device are properly sealed after the first inner sealing process or the second inner sealing process is completed. Therefore, the electricity storage device 100 can be suitably manufactured. The state in which the packaging films 211 and 212 for the electricity storage device are not properly sealed includes, for example, the first state, the second state, or the third state. The first state is a state in which the packaging films 211 and 212 for the electricity storage device are sealed with a foreign object in between. The second state is a state in which a part that should be sealed is not sealed. The third state is a state in which a part that should not be sealed is sealed. After the second inner sealing process, the initial charge/discharge process of step S16 and the aging process of step S17 are carried out in order.

The degassing process in step S18 is carried out in parallel with the initial charge/discharge process and the aging process. In this embodiment 1, the packaging films 211 and 212 for the electricity storage device are gas permeable, so that gases such as carbon dioxide generated from the electricity storage device element 120 during the initial charge/discharge process and the aging process are discharged to the outside through the packaging films 211 and 212 for the electricity storage device. After the degassing process, the main charging process in step S19 is carried out.

The outer packaging process in step S20 is carried out after the main charging process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S21 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221 and 222 is sealed to form the periphery seal portion 150.

[Characteristics of the energy storage device]
In the electricity storage device 100 of the first embodiment, the electricity storage device packaging films 211, 212 are gas permeable, so there is no need to form an auxiliary chamber for temporarily storing gas generated from the electricity storage device element 120 in an initial filling step or the like, which will be described later. This makes it possible to simplify the manufacturing process for the electricity storage device 100. Furthermore, the amount of material used for the electricity storage device 100 can be reduced.

[Embodiment 2 of the fourth aspect]
The electricity storage device 100 of the second embodiment differs from the first embodiment in that the electricity storage device packaging films 211, 212 are not transparent, but the other configurations are the same as those of the first embodiment. The electricity storage device 100 of the second embodiment will be described below, focusing on the differences from the second embodiment.

[Method of manufacturing electricity storage device]
14 is a flowchart illustrating an example of a method for manufacturing the power storage device 100 according to the second embodiment. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging process of step S31, as shown in FIG. 15, the electricity storage device element 120 is wrapped in the formed electricity storage device packaging films 211, 212. In the electricity storage device 100 of the second embodiment, an auxiliary chamber 214 is formed to temporarily store gas generated from the electricity storage device element 120 during the initial filling process or the like. For this reason, in the inner packaging process, the electricity storage device element 120 is wrapped in the electricity storage device packaging films 211, 212 that are larger than the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the completed electricity storage device 100. In the auxiliary chamber 214 of the electricity storage device packaging films 211, 212, a storage chamber 215 is formed to store more gas generated from the electricity storage device element 120.

The first inner sealing process of step S32 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 16, the portions of the periphery of the electricity storage device packaging films 211, 212 corresponding to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed so as to extend to the auxiliary chamber 214. Completion of the first inner sealing process forms an opening 213 in a portion 216 that faces the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed, across the auxiliary chamber 214. After the first inner sealing process, the vacuum drying process of step S33 is carried out.

The electrolyte injection process in step S34 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 16).

The second inner sealing step of step S35 is carried out after the electrolyte injection step. As shown in FIG. 17, in the second inner sealing step, the opening 213 is closed by sealing the portion 216 of the periphery of the packaging films 211, 212 for the electricity storage device, where the side seal portion 153 is to be formed, and the portion 216 facing the auxiliary chamber 214. After the second inner sealing step, the initial charge/discharge step of step S36 and the aging step of step S37 are carried out in sequence.

The degassing process in step S38 is carried out after the aging process. In the degassing process, gases such as carbon dioxide generated from the electricity storage device element 120 are temporarily stored in the auxiliary chamber 214 of the electricity storage device packaging films 211 and 212.

The auxiliary chamber removal process in step S39 is carried out after the degassing process. In the auxiliary chamber removal process, the auxiliary chamber 214 is removed by cutting the packaging films 211, 212 for the electricity storage device along the dashed line XA shown in Figure 17 so that the auxiliary chamber 214 is the same size as the inner packaging body 210 of the completed electricity storage device 100.

The inner sealing process of step S40 is carried out after the auxiliary chamber removal process. In the inner sealing process, as shown in FIG. 18, the portion of the periphery of the packaging films 211, 212 for the electricity storage device that corresponds to the side seal portion 153 is sealed. After the inner sealing process, the main charging process of step S41 is carried out.

The outer packaging process in step S42 is carried out after the main charging process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S43 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221 and 222 is sealed to form the periphery seal portion 150.

[Embodiment 3 of the fourth aspect]
The power storage device 300 of the third embodiment differs from the first embodiment in that the configuration of the terminal seal portion 151A is different, but the other configurations are similar to those of the first embodiment. The following describes the power storage device 300 of the third embodiment, focusing on the differences from the first embodiment.

Figure 19 is a cross-sectional view of a terminal seal portion 351A provided in an electricity storage device 300 of embodiment 3. In the terminal seal portion 351A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to one tab film 140. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to one of the tab films 140. The flange portion 222A of the exterior film 222 is joined to the other tab film 140. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the power storage device 300, the inner packaging body 210 is covered by the outer packaging body 220, so that intrusion of moisture and the like from the outside into the internal space S1 of the inner packaging body 210 is suppressed.

[Embodiment 4 of the fourth aspect]
The power storage device 400 of the fourth embodiment differs from the first embodiment in that the configuration of the terminal seal portion 151A is different, but the other configurations are the same as those of the first embodiment. The following describes the power storage device 400 of the fourth embodiment, focusing on the differences from the first embodiment.

Figure 20 is a cross-sectional view of a terminal seal portion 451A provided in an electricity storage device 400 of embodiment 4. The electricity storage device 400 does not have a tab film 140. In the terminal seal portion 451A of the electricity storage device 400, from the top, an exterior film 221, a packaging film for the electricity storage device 211, a metal terminal 130, a packaging film for the electricity storage device 212, and an exterior film 222 are laminated and integrated.

The end 221X of the flange portion 221A is located closer to the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. The end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the power storage device. The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the power storage device. The end portion 222X of the flange portion 222A is located closer to the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end portion 222X of the flange portion 222A may be located in the same position as the end portion 212X of the packaging film 212 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device.

[Characteristics of the energy storage device]
According to the electricity storage device 400, the number of parts is reduced because the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140. In addition, the manufacturing method of the electricity storage device 400 can be simplified.

[Embodiment 5 of the fourth aspect]
The power storage device 500 of the fifth embodiment differs from the fourth embodiment in that the configuration of the terminal seal portion 451A is different, and the other configurations are the same as those of the fourth embodiment. The following describes the power storage device 500 of the fifth embodiment, focusing on the differences from the fourth embodiment.

Figure 21 is a cross-sectional view of a terminal seal portion 551A provided in an electricity storage device 500 of embodiment 5. In the terminal seal portion 551A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to the metal terminal 130. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the metal terminal 130.

The flange portion 221A of the exterior film 221 is joined to the metal terminal 130. The flange portion 222A of the exterior film 222 is joined to the metal terminal 130. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the electricity storage device 500, the inner packaging body 210 is covered by the outer packaging body 220, which prevents moisture and the like from entering the internal space S1 of the inner packaging body 210 from the outside. Moreover, according to the electricity storage device 500, the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140, which reduces the number of parts. Furthermore, the manufacturing method of the electricity storage device 500 can be simplified.

[Modification of the fourth embodiment]
The above-mentioned embodiments of the fourth aspect are examples of possible forms of the electricity storage device and the manufacturing method of the electricity storage device according to the present disclosure, and are not intended to limit the forms. The electricity storage device and the manufacturing method of the electricity storage device according to the present disclosure may take forms different from those exemplified in the respective embodiments. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Below, some examples of modified versions of each embodiment are shown. Note that the following modified versions can be combined with each other as long as there is no technical contradiction.

In the fourth aspect of the electric storage device 100 of the first embodiment, one outer packaging body 220 may be configured to house multiple inner packaging bodies 210 in a state in which the electric storage device elements 120 are housed. In this modification, the sizes of the multiple inner packaging bodies 210 may be different or the same. According to this modification, the multiple electric storage device elements 120 can be connected in series or parallel, so that the voltage can be easily adjusted.

In the electric storage device 100 of the fourth aspect of the first embodiment, the packaging films 211 and 212 for the electric storage device do not have to be transparent. The packaging films 211 and 212 for the electric storage device only need to be gas permeable.

In the electric storage device 100 of the first embodiment of the fourth aspect, the inner packaging body 210 may be constructed by folding one electric storage device packaging film 211 and heat sealing the peripheral portion. Similarly, the outer packaging body 220 may be constructed by folding one exterior film 221 and heat sealing the peripheral portion.

<Fifth aspect>
[Embodiment 1 of the fifth aspect]
FIG. 8 shows a plan view of the electric storage device 100 according to the first embodiment of the fifth aspect. FIG. 22 is a cross-sectional view taken along the line D2-D2 in FIG. 8. In FIG. 8, a portion that is not visible from the outside is partially shown by dotted lines for reference. In the following, for convenience of explanation, unless otherwise specified, the up-down direction in FIG. 8 is referred to as the "front-rear direction", the left-right direction is referred to as the "left-right direction", and the up-down direction in FIG. 22 is referred to as the "up-down direction". However, the orientation of the electric storage device 100 during use is not limited to this. In addition, in FIG. 8, the relative positional relationship between the inner wrapping body 210 and the outer wrapping body 220 is simplified for the sake of simplicity of the drawing.

The energy storage device 100 comprises a housing 110, an energy storage device element 120, a pair of metal terminals 130, and a pair of tab films 140. The housing 110 comprises an internal space S1 and a peripheral seal portion 150. The energy storage device element 120 is housed in the internal space S1 of the housing 110. One end of the metal terminal 130 is joined to the energy storage device element 120, and the other end protrudes outward from the peripheral seal portion 150 of the housing 110. A portion of the area between one end and the other end of the metal terminal 130 is fused to the peripheral seal portion 150 via the tab film 140.

The container 110 includes a container 110A. The container 110A includes an inner packaging body 210 and an outer packaging body 220. The inner packaging body 210 contains the power storage device element 120. The outer packaging body 220 contains the inner packaging body 210 in which the power storage device element 120 is contained. An internal space S1 is formed inside the inner packaging body 210. The inner packaging body 210 includes packaging films 211 and 212 for the power storage device. The outer packaging body 220 includes exterior films 221 and 222. In the outer peripheral portion of the container 110A in a plan view, the inner packaging body 210 and the outer packaging body 220 are heat-sealed and fused to each other, thereby forming a peripheral seal portion 150. The peripheral seal portion 150 forms an internal space S1 of the container 110A that is isolated from the external space in the inner packaging body 210. The peripheral seal portion 150 defines the periphery of the internal space S1 of the container 110A. The heat seal mode referred to here may be heat fusion from a heat source, ultrasonic fusion, or the like. In any case, the peripheral seal portion 150 refers to the portion where the inner wrapping body 210 and the outer wrapping body 220 are fused together to form an integrated unit.

The peripheral seal portion 150 includes a top seal portion 151, a pair of side seal portions 152, 153, and a bottom seal portion 154. The top seal portion 151 includes a portion that is sealed by sandwiching the metal terminal 130 and the tab film 140 (hereinafter referred to as "terminal seal portion 151A"), and extends in the front-rear direction. The pair of side seal portions 152, 153 extend in the left-right direction. The side seal portion 152 and the side seal portion 153 face each other across the internal space S1. The bottom seal portion 154 faces the top seal portion 151 across the internal space S1. The bottom seal portion 154 extends in the front-rear direction.

22, the terminal seal portion 151A of the top seal portion 151 is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. This makes it easy to form the top seal portion 151. Note that the portion of the top seal portion 151 other than the terminal seal portion 151A, in other words, the portion where only the pair of tab films 140 are sandwiched between the inner packaging body 210 and the outer packaging body 220, is formed by stacking, from the top, the exterior film 221, the packaging film for the power storage device 211, one tab film 140, the other tab film 140, the packaging film for the power storage device 212, and the exterior film 222, which are integrated together. Furthermore, the outer portion of the terminal seal portion 151A of the top seal portion 151 (the left portion with the step as the boundary in FIG. 22) is made up of, from the top, the packaging film for the power storage device 211, one tab film 140, the metal terminal 130, the other tab film 140, and the packaging film for the power storage device 212, which are laminated and integrated. Therefore, there is a step between the outer portion of the terminal seal portion 151A where the exterior films 221, 222 are not present and the inner portion of the terminal seal portion 151A where the exterior films 221, 222 are present (the right portion with the step as the boundary in FIG. 22), but FIG. 8 shows an overview of the area of the peripheral seal portion 150, and does not show the step as the boundary.

From the viewpoint of suitably manufacturing the electricity storage device 100, the electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are preferably transparent overall. From the viewpoint of easily manufacturing the electricity storage device 100, the electricity storage device packaging films 211, 212 are preferably gas permeable. Below, preferred examples of the electricity storage device packaging films 211, 212 constituting the inner packaging body 210 are described. Note that below, when there is no particular distinction between the electricity storage device packaging films 211, 212, the electricity storage device packaging films 211, 212 may be collectively referred to as the electricity storage device packaging film 10.

[Laminate structure and physical properties of the packaging film for electricity storage devices according to the fifth embodiment]
1 to 4, the packaging film 10 for an electricity storage device according to the fifth embodiment includes at least a heat-sealable resin layer 1. When assembling an electricity storage device using the packaging film 10 for an electricity storage device and an electricity storage device element, the heat-sealable resin layers 1 of the packaging film 10 for an electricity storage device are placed opposite each other, and the peripheral portions are heat-sealed to form a space in which the electricity storage device element is housed.

The packaging film 10 for the electricity storage device may be composed only of the heat-sealable resin layer 1, as shown in FIG. 1. When the packaging film 10 for the electricity storage device is composed only of the heat-sealable resin layer 1, it is preferable that at least one surface of the heat-sealable resin layer 1 has adhesive properties to metal.

In addition, the packaging film 10 for an electricity storage device according to the fifth embodiment is preferably composed of a laminate including at least a resin layer 2 and a heat-sealable resin layer 1, as shown in Figs. 2 to 4. In such a packaging film 10 for an electricity storage device, the resin layer 2 is on the outside, and the heat-sealable resin layer 1 is on the inside (the innermost layer). When the packaging film 10 for an electricity storage device is composed of a laminate including a resin layer 2 and the heat-sealable resin layer 1, it is preferable to impart adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1, and it is more preferable to impart adhesion to metal to the inner surface of the heat-sealable resin layer 1 that faces the metal terminal 130.

Furthermore, the packaging film 10 for a storage battery device according to the fifth embodiment is preferably composed of a laminate including at least the resin layer 2, the substrate 3, and the heat-sealable resin layer 1, as shown in Figs. 3 and 4. In such a packaging film 10 for a storage battery device, the resin layer 2 is on the outside, the heat-sealable resin layer 1 is on the inside (the innermost layer), and the substrate 3 is located between the resin layer 2 and the heat-sealable resin layer 1. Even when the packaging film 10 for a storage battery device is composed of a laminate including the resin layer 2, the substrate 3, and the heat-sealable resin layer 1, it is preferable to impart adhesion to metal to at least one of the outer surface of the resin layer 2 and the inner surface of the heat-sealable resin layer 1, and it is more preferable to impart adhesion to metal to the inner surface of the heat-sealable resin layer 1 that faces the metal terminal 130.

As shown in FIG. 2, an adhesive layer 4 can be provided between the resin layer 2 and the heat-sealable resin layer 1, and as shown in FIG. 4, an adhesive layer 5 can be provided between the heat-sealable resin layer 1 and the substrate 3.

The packaging film 10 for electricity storage devices of the fifth embodiment preferably has a _CO2 permeation amount in an environment of 30°C of 100 cc·100 μm/ ^m2 /24 hr/atm or more, more preferably about 200 cc·100 μm/ ^m2 /24 hr/atm or more, even more preferably about 300 cc·100 μm/ ^m2 /24 hr/atm or more, and even more preferably about 500 cc·100 μm/ ^m2 /24 hr/atm or more. The _CO2 permeation amount of the packaging film 10 for an electricity storage device of the fifth embodiment is, for example, about 2000cc·100μm/ ^m2 /24hr/atm or less, preferably about 1000cc·100μm/ ^m2 /24hr/atm or less, and more preferably about 800cc·100μm/ ^m2 /24hr/atm or less, and preferred ranges are about 100 to 2000cc·100μm/ ^m2 /24hr/atm, about 100 to 1000cc·100μm/ ^m2 /24hr/atm, about 100 to 800cc·100μm/ ^m2 /24hr/atm, and about 200 to 2000cc·100μm/m2 ^. /24hr/atm, 200-1000cc・100μm/m ² /24hr/atm, 200-800cc・100μm/m ² /24hr/atm, 300-2000cc・100μm/m ² /24hr/atm approximately, 300-1000cc・100μm/m ² /24hr/atm approximately, 300-800cc・100μm/m ² /24hr/atm approximately, 500-2000cc・100μm/m ² /24hr/atm or so, 500-1000cc/100μm/m ² /24hr/atm or so, 500-800cc/100μm/ ^m2 The _CO2 permeation amount of the packaging film for an electricity storage device is measured by the following method.

[Measurement of _CO2 permeation amount]
In accordance with JIS K7126-1 (Plastics - Films and sheets - Gas permeability test method - Part 1: Differential pressure method), the amount of _CO2 that has permeated through a φ60 mm piece of the packaging film 10 for electricity storage devices in an atmosphere at 30°C is quantitatively analyzed by gas chromatography to measure the amount of CO2 permeated.

When imparting shielding properties to the packaging film 10 for an electricity storage device of the fifth embodiment, at least one layer included in the packaging film 10 for an electricity storage device may be a shielding layer S having shielding properties. For example, FIG. 2 illustrates a configuration in which the adhesive layer 4 that bonds between the resin layer 2 and the heat-sealable resin layer 1 is the shielding layer S, and FIG. 4 illustrates a configuration in which the adhesive layer 4 that bonds between the resin layer 2 and the substrate 3 is the shielding layer S. In the fifth embodiment, any layer included in the packaging film 10 for an electricity storage device may be the shielding layer S.

Although not shown in the figure, a surface coating layer or the like may be further provided on the outside of the resin layer 2 (the side opposite to the heat-sealable resin layer 1) as necessary.

The thickness of the laminate constituting the packaging film 10 for electric storage devices is not particularly limited, but from the viewpoint of cost reduction and energy density improvement, for example, it is 190 μm or less, preferably about 180 μm or less, about 170 μm or less. From the viewpoint of maintaining the function of the packaging film for electric storage devices to protect the electric storage device elements, the thickness of the laminate constituting the packaging film 10 for electric storage devices is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more. Preferred ranges of the laminate constituting the packaging film 10 for electric storage devices include, for example, about 35 to 190 μm, about 35 to 180 μm, about 35 to 170 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 170 μm, about 60 to 190 μm, about 60 to 180 μm, and about 60 to 170 μm, with about 45 to 170 μm being particularly preferred.

In the packaging film 10 for the electric storage device, the ratio of the total thickness of the resin layer 2, adhesive layer 4, substrate 3, adhesive layer 5, and heat-sealable resin layer 1 to the thickness (total thickness) of the laminate constituting the packaging film 10 for the electric storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the packaging film 10 for the electric storage device of the fifth aspect includes the resin layer 2, adhesive layer 4, substrate 3, adhesive layer 5, and heat-sealable resin layer 1, the ratio of the total thickness of each of these layers to the thickness (total thickness) of the laminate constituting the packaging film 10 for the electric storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Also, even when the packaging film 10 for an electricity storage device of the fifth embodiment is a laminate including a resin layer 2, an adhesive layer 4, and a heat-sealable resin layer 1, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging film 10 for an electricity storage device can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

The laminate constituting the packaging film 10 for the electric storage device of the fifth aspect can have a total light transmittance measured in accordance with the provisions of JIS K7361-1:1997 of, for example, 20% or less, 15% or less, 10% or less, 8% or less, etc. The laminate constituting the packaging film 10 for the electric storage device of the fifth aspect can have a total light transmittance measured in accordance with the provisions of JIS K7361-1:1997 of, for example, 80% or more, 85% or more, 90% or more, etc. The lower the total light transmittance, the higher the shielding property of the packaging film 10 for the electric storage device. On the other hand, the higher the total light transmittance, the higher the light transmittance of the packaging film 10 for the electric storage device. The lower limit of the total light transmittance is 0%, and the upper limit is 100%. The total light transmittance of the packaging film for power storage devices is measured in accordance with the measurement method specified in JIS K7361-1:1997 using a commercially available spectrophotometer (for example, JASCO's UV-Vis-Near-Infrared Spectrophotometer V-670) in the visible light region (400-700 nm), and the average value is taken as the total light transmittance. The measurement conditions are as follows: a halogen lamp is used as the light source, UV/Vis bandwidth: 5.0 nm, scanning speed: 1000 nm/min, response: Medium, data acquisition interval: 1.0 nm.

The packaging film 10 for the electricity storage device can be black. When the packaging film 10 for the electricity storage device is black, the packaging film 10 for the electricity storage device has high shielding properties and is highly effective in preventing counterfeiting. In addition, during the manufacturing process of the electricity storage device, it becomes possible to grasp the position with a sensor with higher accuracy, and it becomes possible to transport the packaging film 10 for the electricity storage device and seal the electricity storage device elements more accurately. Furthermore, it is possible to unify the electricity storage device and other electrical equipment in black, giving the product a luxurious feel.

<Layers Constituting the Packaging Film for Electricity Storage Devices of the Fifth Aspect>
Each layer constituting the packaging film for electricity storage devices of the fifth embodiment is the same as that of the packaging films for electricity storage devices of the first and second embodiments, and therefore description thereof will be omitted.

[Method of manufacturing packaging film for power storage devices]
The method for producing the packaging film for an electricity storage device is not particularly limited as long as the packaging film for an electricity storage device of the fifth aspect can be obtained. For example, when the packaging film for an electricity storage device of the fifth aspect includes a resin layer 2 and a heat-sealable resin layer 1, the method includes a step of producing a laminate in which at least a resin layer and a heat-sealable resin layer are laminated from the outside, and the laminate preferably has a _CO2 permeation amount of 100 cc·100 μm/ ^m2 /24 hr/atm or more in a temperature 30° C. environment.

An example of a manufacturing method in which the packaging film for an electricity storage device of the fifth embodiment is composed of a laminate having the resin layer 2, the adhesive layer 4, the substrate 3, the adhesive layer 5, and the heat-sealable resin layer 1 in this order is as follows. First, the materials constituting each layer are prepared. Next, the resin layer 2 and the substrate 3 are laminated via the adhesive layer 4, and the substrate 3 and the heat-sealable resin layer 1 are laminated via the adhesive layer 5. Specifically, the resin layer 2 and the substrate 3 are laminated by a dry lamination method or the like using an adhesive that forms the adhesive layer 4, so that the resin layer 2, the adhesive layer 4, and the substrate 3 are laminated, and further, the substrate 3 and the heat-sealable resin layer 1 are laminated by a dry lamination method or the like using an adhesive that forms the adhesive layer 5, thereby manufacturing the packaging film for an electricity storage device 10. In addition, when the resin layer 2, the substrate 3, and the heat-sealable resin layer 1 are laminated without the adhesive layers 4 and 5, the packaging film 10 for the electric storage device can be manufactured by melt-extruding the resin constituting the resin layer 2 onto one side of the substrate 3, and melt-extruding the resin constituting the heat-sealable resin layer 1 onto the other side of the substrate 3. When a colored layer is provided, the colored layer is formed on the surface of the resin layer 2, and then laminated with the substrate 3 and the heat-sealable resin layer 1. When a surface coating layer is provided, it can be formed, for example, by applying the above-mentioned resin composition for forming the surface coating layer onto the surface of the resin layer 2 and curing it.

To strengthen the adhesive properties of the adhesive layers 4 and 5, the packaging film 10 for the electricity storage device may be subjected to a heat treatment.

The shape of the inner packaging body 210 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The inner packaging body 210 of the present embodiment 1 has a shape as shown in FIG. 22 and is manufactured by heat sealing a packaging film for an electricity storage device 212 formed into a tray shape and a packaging film for an electricity storage device 211 also formed into a tray shape and superimposed on the packaging film for an electricity storage device 212, along the outer periphery in a plan view. The packaging film for an electricity storage device 212 includes a flange portion 212A of a square ring shape corresponding to the outer periphery in a plan view, and a molded portion 212B that is continuous with the inner edge of the flange portion 212A and bulges downward from there. Similarly, the electricity storage device packaging film 211 includes a rectangular ring-shaped flange portion 211A that corresponds to the outer periphery in a plan view, and a flange portion 211B that is continuous with the inner edge of the flange portion 211A and bulges upward from the flange portion 211A. The electricity storage device packaging films 211 and 212 are overlapped such that the respective molded portions 211B and 212B bulge in opposite directions. In this state, the flange portion 211A of the electricity storage device packaging film 211 and the flange portion 212A of the electricity storage device packaging film 212 are heat-sealed so as to be integrated, forming a part of the peripheral seal portion 150. Note that one of the electricity storage device packaging films 211 and 212 may be in the form of a sheet.

The exterior films 221, 222 constituting the outer packaging body 220 are, for example, made of a resin molded product or film. The resin molded product referred to here can be manufactured by injection molding, compressed air molding, vacuum molding, blow molding, or other methods, and in-mold molding may be used to impart design and functionality. The type of resin may be polyolefin, polyester, nylon, ABS, or other materials. The film referred to here is, for example, a resin film that can be manufactured by an inflation method or a T-die method, or a resin film laminated on a metal foil or metal plate. The film referred to here may or may not be stretched, and may be a single-layer film or a multilayer film. The multilayer film referred to here may be manufactured by a coating method, may be a film in which multiple films are bonded together with an adhesive, or may be manufactured by a multilayer extrusion method.

The exterior films 221 and 222 can be configured in various ways, but in this embodiment 1, they are composed of a laminate film. The laminate film can be a laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated. The base layer functions as a base material for the exterior films 221 and 222, and is typically an insulating resin layer that forms the outer layer side of the outer packaging body 220. The barrier layer has a function of preventing at least moisture and the like from penetrating into the power storage device 100 in addition to improving the strength of the exterior films 221 and 222, and is typically a metal layer made of aluminum alloy foil or the like. The heat-sealable resin layer is typically made of a heat-sealable resin such as polyolefin, and forms the innermost layer of the outer packaging body 220.

The shape of the outer packaging body 220 is not particularly limited, and can be, for example, a bag-like (pouch-like) shape. The bag-like shape here can be a three-sided seal type, a four-sided seal type, a pillow type, a gusset type, or the like. The container 110A of the present embodiment 1 has a shape as shown in FIG. 22 and is manufactured by heat-sealing an exterior film 222 formed into a tray shape and an exterior film 221 similarly formed into a tray shape and superimposed on the exterior film 222 along the outer periphery in a plan view. The exterior film 222 includes a square ring-shaped flange portion 222A corresponding to the outer periphery in a plan view, and a molded portion 222B that is continuous with the inner edge of the flange portion 222A and bulges downward therefrom. Similarly, the exterior film 221 includes a square ring-shaped flange portion 221A corresponding to the outer periphery in a plan view, and a flange portion 221B that is continuous with the inner edge of the flange portion 221A and bulges upward therefrom. The exterior films 221 and 222 are overlapped so that the respective molded portions 221B and 222B bulge in opposite directions. In this state, the flange portion 221A of the exterior film 221 and the flange portion 222A of the exterior film 222 are heat sealed to be integrated together, forming a part of the peripheral seal portion 150. Note that one of the exterior films 221 and 222 may be in the form of a sheet.

As shown in FIG. 22, in the terminal seal portion 151A, a portion of the flange portion 211A of the packaging film 211 for the power storage device is joined to one of the tab films 140. A portion of the flange portion 212A of the packaging film 212 for the power storage device is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the electricity storage device. The end 221X of the flange portion 221A is located closer to the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 211X of the packaging film 211 for the electricity storage device.

The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the electricity storage device. The end 222X of the flange portion 222A is located closer to the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end 222X of the flange portion 222A may be located in the same position as the end 212X of the packaging film 212 for the electricity storage device in the left-right direction, or farther from the electricity storage device element 120 than the end 212X of the packaging film 212 for the electricity storage device.

The power storage device element 120 has at least a positive electrode, a negative electrode, and an electrolyte, and is, for example, a lithium ion battery (secondary battery) or a power storage member such as a capacitor.

The metal terminal 130 is a metal terminal used for inputting and outputting power to and from the power storage device element 120. The metal terminal 130 is arranged, for example, in the top seal portion 151 of the container 110A, with one terminal constituting a positive electrode side terminal and the other terminal constituting a negative electrode side terminal. One end in the left-right direction of each metal terminal 130 is electrically connected to an electrode (positive electrode or negative electrode) of the power storage device element 120 in the internal space S1 of the container 110A, and the other end protrudes outward from the peripheral seal portion 150. The above-mentioned form of the power storage device 100 is particularly preferable for use in electric vehicles such as electric vehicles and hybrid vehicles that use a large number of power storage devices 100 connected in series at high voltage. The mounting positions of the two metal terminals 130 that constitute the positive and negative electrode terminals are not particularly limited, and may be arranged, for example, in the side seal portions 152, 153 or bottom seal portion 154 of the peripheral seal portion 150.

The metal material constituting the metal terminal 130 is, for example, aluminum, nickel, copper, etc. When the power storage device element 120 is a lithium ion battery, the metal terminal 130 connected to the positive electrode is typically made of aluminum, etc., and the metal terminal 130 connected to the negative electrode is typically made of copper, nickel, etc.

The tab film 140 is a so-called adhesive film, and is configured to adhere to both the electricity storage device packaging films 211, 212 and the metal terminal 130. By using the tab film 140, the metal terminal 130 and the innermost layer (thermally adhesive resin layer) of the electricity storage device packaging films 211, 212 can be fixed together even if they are made of different materials. The tab film 140 is integrated by being fused and fixed to the metal terminal 130 in advance, and the electricity storage device packaging films 211, 212 are fused to the metal terminal 130 to which the tab film 140 is fixed.

The power storage device 100 according to the first embodiment of the fifth embodiment includes a functional object 230 so as to have a high added-value function in addition to the functions of a general power storage device. The functional object 230 has at least one function of shock absorption, flame retardancy, cooling, and fire extinguishing. The functional object 230 is disposed between the inner wrapping body 210 and the outer wrapping body 220. The specific form of the functional object 230 can be selected arbitrarily. The functional object 230 may be in the form of a sheet such as a film, a liquid that can be applied to a film, or a granular or liquid form having a predetermined fluidity (viscosity).

When the functional object 230 is in the form of a sheet such as a film, the functional object 230 is, for example, wrapped around the inner packaging body 210 and joined to the inner packaging body 210. The functional object 230 may be joined to the inner packaging body 210 so as to cover at least a portion of the surface of the inner packaging body 210, but it is preferable that the functional object 230 is joined to the inner packaging body 210 so as to cover substantially the entire surface of the inner packaging body 210.

When the functional object 230 is a liquid that can be applied to a film or the like, the functional object 230 is applied to the surface of the inner packaging body 210 or the inner surface of the outer packaging body 220. The functional object 230 may be applied to at least a portion of the surface of the inner packaging body 210, but it is preferable that the functional object 230 is applied to substantially the entire surface of the inner packaging body 210. Note that the functional object 230 being a liquid that can be applied to a film or the like includes a state in which it can be sprayed onto the inner packaging body 210 and the outer packaging body 220 by a spray or the like.

When the functional object 230 is in a granular or liquid form having a predetermined fluidity (viscosity), the functional object 230 is filled into the space between the inner packaging body 210 and the outer packaging body 220. The functional object 230 may be filled into at least a portion of the space between the inner packaging body 210 and the outer packaging body 220, but it is preferable that the functional object 230 is filled into almost the entire space between the inner packaging body 210 and the outer packaging body 220.

The functional object 230 having shock absorbing properties is, for example, a non-crosslinked highly expanded polyethylene sheet, an electron beam crosslinked highly expanded polyethylene sheet, a heat-welded composite highly expanded polyethylene sheet, or nitrile rubber.

The flame-retardant functional object 230 is, for example, a flame-retardant polycarbonate film or a flame-retardant polyethylene terephthalate film.

The functional object 230 having cooling properties is, for example, a highly thermally conductive film, a highly thermally conductive adhesive sheet, or a highly thermally conductive graphite sheet.

The functional object 230 having fire extinguishing properties is, for example, a fire extinguishing agent or a film containing a fire extinguishing agent (hereinafter referred to as a "fire-resistant film"). The fire extinguishing agent is, for example, a common powder-based fire extinguishing agent such as potassium salt, sodium bicarbonate, or phosphate, an ABC fire extinguishing agent, a BC fire extinguishing agent, or sand. When a fire extinguishing agent is used as the functional object 230, a fire extinguishing agent that does not contain water is preferable from the viewpoint of suppressing a decrease in the function of the power storage device 100.

A known fireproof film can be used as the fireproof film. The fireproof film is, for example, a laminated film having a substrate (substrate layer) and a fire-extinguishing agent-containing layer in this order. The fire-extinguishing agent-containing layer may be provided on at least a portion of one surface of the substrate, but is preferably provided on the entire surface of the substrate. The substrate is within the substrate and has a region carrying the fire-extinguishing agent component and binder resin on the side of the fire-extinguishing agent-containing layer.

The fireproof film can be used with its extinguishing agent-containing layer facing an object that may ignite. In the present embodiment 1, the fireproof film is bonded to the inner surface of the outer wrapping body 220 so that the extinguishing agent-containing layer faces the surface of the inner wrapping body 210. For example, if the electricity storage device element 120 ignites, initial extinguishing is performed by the aerosol generated from the extinguishing agent-containing layer.

The substrate has voids, and may be, for example, a nonwoven fabric made by entangling nonflammable or flame-retardant fibers, or a woven fabric made by weaving nonflammable or flame-retardant fibers. Examples of nonflammable or flame-retardant fibers include glass fibers, ceramic fibers, metal fibers, cellulose fibers, polyester fibers, carbon fibers, graphite fibers, and thermosetting resin fibers. From the viewpoint of excellent nonflammability, glass fibers and ceramic fibers can be used. Examples of substrates include glass cloth and nonflammable paper. As the substrate, a nonflammable substrate that meets the first class fire resistance specified in JIS Z 2150-1966 can also be used.

The supported regions in the substrate are formed when a coating film is formed on the surface of the substrate using a coating liquid containing the extinguishing agent component and the binder resin, and a portion of the coating liquid penetrates into the substrate. The substrate can be said to have regions that support the extinguishing agent component and the binder resin, and regions that do not support them.

The extinguishing agent-containing layer is a layer that contains an extinguishing agent component and a binder resin. The extinguishing agent component generates an aerosol by combustion. The extinguishing agent component contains, for example, at least an inorganic oxidizing agent and a radical generator. The radical generator has the effect of stabilizing combustion radicals and suppressing the chain reaction of combustion (negative catalytic action).

[Method of manufacturing electricity storage device]
23 is a flowchart showing an example of a method for manufacturing the power storage device 100. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging process of step S11, as shown in FIG. 11, the formed electricity storage device packaging films 211, 212 are wrapped around the electricity storage device element 120. In the electricity storage device 100 of the first embodiment, the electricity storage device packaging films 211, 212 are gas permeable, so there is no need to form a sub-chamber for temporarily storing the gas generated from the electricity storage device element 120 in the initial filling process described below. Therefore, in the inner packaging process, the electricity storage device element 120 is wrapped around the electricity storage device packaging films 211, 212 that are substantially the same size as the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the finished electricity storage device 100. This simplifies the manufacturing process of the electricity storage device 100. In addition, the amount of material used for the electricity storage device 100 can be reduced. "Substantially the same size" includes cases where the size is larger than the electricity storage device packaging films 211, 212 included in the inner packaging body 210 of the finished electricity storage device 100 to the extent that a sub-chamber cannot be formed. Note that the electricity storage device element 120 is connected to the metal terminal 130 in advance, and the tab film 140 is joined to the metal terminal 130.

The first inner sealing process in step S12 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 12, the portions of the periphery of the electricity storage device packaging films 211, 212 that correspond to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed. Completion of the first inner sealing process forms an opening 213 in the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed. After the first inner sealing process, the vacuum drying process in step S13 is carried out.

The electrolyte injection process in step S14 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 12).

The second inner sealing step in step S15 is performed after the electrolyte injection step. As shown in FIG. 18, in the second inner sealing step, the opening 213 is closed by sealing the portion of the periphery of the packaging films 211 and 212 for the power storage device where the side seal portion 153 is to be formed. According to the power storage device 100, since the packaging films 211 and 212 for the power storage device have transparency, it is easy to check whether the packaging films 211 and 212 for the power storage device are properly sealed after the first inner sealing step or the second inner sealing step is completed. Therefore, the power storage device 100 can be suitably manufactured. The state in which the packaging films 211 and 212 for the power storage device are not properly sealed includes, for example, the first state, the second state, or the third state. The first state is a state in which the packaging films 211 and 212 for the power storage device are sealed with a foreign object in between. The second state is a state in which a part that should be sealed is not sealed. The third state is a state in which a part that should not be sealed is sealed. After the second inner sealing process, the initial charge/discharge process of step S16 and the aging process of step S17 are carried out in order.

The degassing process in step S18 is carried out in parallel with the initial charge/discharge process and the aging process. In this embodiment 1, the packaging films 211 and 212 for the electricity storage device are gas permeable, so that gases such as carbon dioxide generated from the electricity storage device element 120 during the initial charge/discharge process and the aging process are discharged to the outside through the packaging films 211 and 212 for the electricity storage device. After the degassing process, the main charging process in step S19 is carried out.

The placement process of step S20 is carried out after this filling process. In the placement process, the functional object 230 is placed between the inner packaging body 210 and the outer packaging body 230 depending on the specific form of the functional object 230. When the functional object 230 is in the form of a sheet such as a film, the functional object 230 is, for example, wrapped around the inner packaging body 210 and joined to the inner packaging body 210. When the functional object 230 is a liquid that can be applied to a film or the like, the functional object 230 is applied to the surface of the inner packaging body 210 or the inner surface of the outer packaging body 220.

The outer packaging process of step S21 is carried out after the arrangement process. In the outer packaging process, the inner packaging body 210 containing the energy storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S22 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221, 222 is sealed to form the periphery seal portion 150. If the functional object 230 is in a granular or liquid form with a predetermined fluidity (viscosity), the placement process may be carried out in the outer sealing process, for example, by filling the opening in the portion where the bottom seal portion 154 is to be formed after the top seal portion 151, side seal portions 152, 153 of the periphery seal portion 150 are formed.

[Characteristics of the energy storage device]
The power storage device 100 has high added value because it includes the functional object 230 .

[Embodiment 2 of the fifth embodiment]
The electricity storage device 100 of the second embodiment differs from the first embodiment in that the electricity storage device packaging films 211, 212 are not gas permeable, or in that, compared to the first embodiment, they do not have gas permeability to the extent that the degassing step of step S18 described above is performed, but the other configurations are similar to those of the first embodiment. The electricity storage device 100 of the second embodiment will be described below, focusing on the differences from the second embodiment.

[Method of manufacturing electricity storage device]
24 is a flowchart illustrating an example of a method for manufacturing the power storage device 100 according to the second embodiment. The method for manufacturing the power storage device 100 includes a plurality of steps.

In the inner packaging step of step S31, as shown in FIG. 15, the formed electricity storage device packaging films 211, 212 are used to wrap the electricity storage device element 120. In the electricity storage device 100 of the second embodiment, since the electricity storage device packaging films 211, 212 are not gas permeable, it is preferable to form a sub-chamber 214 for temporarily storing gas generated from the electricity storage device element 120 during the initial filling step or the like. For this reason, in the inner packaging step, the electricity storage device element 120 is wrapped in the electricity storage device packaging films 211, 212 that are larger than the electricity storage device packaging films 211, 212 provided in the inner packaging body 210 of the completed electricity storage device 100. In the sub-chamber 214 of the electricity storage device packaging films 211, 212, a storage chamber 215 for storing more gas generated from the electricity storage device element 120 is formed.

The first inner sealing process of step S32 is carried out after the inner packaging process. In the first inner sealing process, as shown in FIG. 16, the portions of the periphery of the electricity storage device packaging films 211, 212 corresponding to the top seal portion 151, the side seal portion 152, and the bottom seal portion 154 are sealed so as to extend to the auxiliary chamber 214. Completion of the first inner sealing process forms an opening 213 in a portion 216 that faces the portion of the periphery of the electricity storage device packaging films 211, 212 where the side seal portion 153 is to be formed, across the auxiliary chamber 214. After the first inner sealing process, the vacuum drying process of step S33 is carried out.

The electrolyte injection process in step S34 is carried out after the vacuum drying process. In the electrolyte injection process, the electrolyte is injected through the opening 213 (see FIG. 16).

The second inner sealing step of step S35 is carried out after the electrolyte injection step. As shown in FIG. 17, in the second inner sealing step, the opening 213 is closed by sealing the portion 216 of the periphery of the packaging films 211, 212 for the electricity storage device, where the side seal portion 153 is to be formed, and the portion 216 facing the auxiliary chamber 214. After the second inner sealing step, the initial charge/discharge step of step S36 and the aging step of step S37 are carried out in sequence.

The degassing process in step S38 is carried out after the aging process. In the degassing process, gases such as carbon dioxide generated from the electricity storage device element 120 are temporarily stored in the auxiliary chamber 214 of the electricity storage device packaging films 211 and 212.

The auxiliary chamber removal process in step S39 is carried out after the degassing process. In the auxiliary chamber removal process, the auxiliary chamber 214 is removed by cutting the packaging films 211, 212 for the electricity storage device along the dashed line XA shown in Figure 17 so that the auxiliary chamber 214 is the same size as the inner packaging body 210 of the completed electricity storage device 100.

The inner sealing process of step S40 is carried out after the auxiliary chamber removal process. In the inner sealing process, as shown in FIG. 18, the portion of the periphery of the packaging films 211, 212 for the electricity storage device that corresponds to the side seal portion 153 is sealed. After the inner sealing process, the main charging process of step S41 is carried out.

The placement process of step S42 is carried out after this filling process. In the placement process, the functional object 230 is placed between the inner packaging body 210 and the outer packaging body 230 depending on the specific form of the functional object 230. When the functional object 230 is in the form of a sheet such as a film, the functional object 230 is, for example, wrapped around the inner packaging body 210 and joined to the inner packaging body 210. When the functional object 230 is a liquid that can be applied to a film or the like, the functional object 230 is applied to the surface of the inner packaging body 210 or the inner surface of the outer packaging body 220.

The outer packaging process in step S43 is carried out after the placement process. In the outer packaging process, the inner packaging body 210 containing the power storage device element 120 is wrapped in exterior films 221 and 222.

The outer sealing process in step S44 is carried out after the outer packaging process. In the outer sealing process, the periphery of the exterior films 221, 222 is sealed to form the periphery seal portion 150. If the functional object 230 is in a granular or liquid form with a predetermined fluidity (viscosity), the placement process may be carried out in the outer sealing process, for example, by filling the opening in the portion where the bottom seal portion 154 is to be formed after the top seal portion 151, side seal portions 152, 153 of the periphery seal portion 150 are formed.

[Characteristics of the energy storage device]
According to the power storage device 100 of the third embodiment, since the functional object 230 is provided, the same effects as those of the power storage device 100 of the first embodiment can be obtained.

[Embodiment 3 of the fifth embodiment]
The power storage device 300 of the third embodiment differs from the first embodiment in that the configuration of the terminal seal portion 151A is different, but the other configurations are similar to those of the first embodiment. The following describes the power storage device 300 of the third embodiment, focusing on the differences from the first embodiment.

Figure 25 is a cross-sectional view of a terminal seal portion 351A provided in an electricity storage device 300 of embodiment 3. In the terminal seal portion 351A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to one tab film 140. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the other tab film 140.

The flange portion 221A of the exterior film 221 is joined to one of the tab films 140. The flange portion 222A of the exterior film 222 is joined to the other tab film 140. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the power storage device 300, the inner packaging body 210 is covered by the outer packaging body 220, so that intrusion of moisture and the like from the outside into the internal space S1 of the inner packaging body 210 is suppressed.

[Embodiment 4 of the fifth embodiment]
The power storage device 400 of the fourth embodiment differs from the first embodiment in that the configuration of the terminal seal portion 151A is different, but the other configurations are the same as those of the first embodiment. The following describes the power storage device 400 of the fourth embodiment, focusing on the differences from the first embodiment.

Figure 26 is a cross-sectional view of a terminal seal portion 451A provided in an electricity storage device 400 of embodiment 4. The electricity storage device 400 does not have a tab film 140. In the terminal seal portion 451A of the electricity storage device 400, from the top, an exterior film 221, a packaging film for the electricity storage device 211, a metal terminal 130, a packaging film for the electricity storage device 212, and an exterior film 222 are laminated and integrated.

The end 221X of the flange portion 221A is located closer to the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. The end 221X of the flange portion 221A may be located in the same position as the end 211X of the packaging film 211 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end 211X of the packaging film 211 for the power storage device.

The flange portion 221A of the exterior film 221 is joined to the flange portion 211A of the packaging film 211 for the power storage device. The flange portion 222A of the exterior film 222 is joined to the flange portion 212A of the packaging film 212 for the power storage device. The end portion 222X of the flange portion 222A is located closer to the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device. Therefore, at least a part of the outer edge of the inner packaging body 210 is exposed from the outer packaging body 220. Note that the end portion 222X of the flange portion 222A may be located in the same position as the end portion 212X of the packaging film 212 for the power storage device in the left-right direction, or farther from the power storage device element 120 than the end portion 212X of the packaging film 212 for the power storage device.

[Characteristics of the energy storage device]
According to the electricity storage device 400, the number of parts is reduced because the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140. In addition, the manufacturing method of the electricity storage device 400 can be simplified.

[Embodiment 5 of the fifth embodiment]
The power storage device 500 of the fifth embodiment differs from the fourth embodiment in that the configuration of the terminal seal portion 451A is different, and the other configurations are the same as those of the fourth embodiment. The following describes the power storage device 500 of the fifth embodiment, focusing on the differences from the fourth embodiment.

Figure 27 is a cross-sectional view of a terminal seal portion 551A provided in an electricity storage device 500 of embodiment 5. In the terminal seal portion 551A, a portion of the flange portion 211A of the electricity storage device packaging film 211 is joined to the metal terminal 130. A portion of the flange portion 212A of the electricity storage device packaging film 212 is joined to the metal terminal 130.

The flange portion 221A of the exterior film 221 is joined to the metal terminal 130. The flange portion 222A of the exterior film 222 is joined to the metal terminal 130. The end portion 221X of the flange portion 221A is located farther from the power storage device element 120 than the end portion 211X of the power storage device packaging film 211. The end portion 222X of the flange portion 222A is located farther from the power storage device element 120 than the end portion 212X of the power storage device packaging film 212. Therefore, the entire inner packaging body 210 is covered by the outer packaging body 220.

[Characteristics of the energy storage device]
According to the electricity storage device 500, the inner packaging body 210 is covered by the outer packaging body 220, which prevents moisture and the like from entering the internal space S1 of the inner packaging body 210 from the outside. Moreover, according to the electricity storage device 500, the electricity storage device packaging films 211, 212 and the metal terminal 130 are joined without the tab film 140, which reduces the number of parts. Furthermore, the manufacturing method of the electricity storage device 500 can be simplified.

[Modification of the fifth embodiment]
The above-mentioned embodiments are examples of possible forms of the electricity storage device and the manufacturing method of the electricity storage device according to the fifth embodiment, and are not intended to limit the forms. The electricity storage device and the manufacturing method of the electricity storage device according to the present disclosure may take forms different from those exemplified in the embodiments. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Below, some examples of modified versions of each embodiment are shown. The following modified versions can be combined with each other as long as there is no technical contradiction.

In the energy storage device 100 of the first embodiment, the functional object 230 may be contained in at least one of the energy storage device packaging films 211, 212 or the exterior films 221, 222. That is, in the energy storage device 100 of this modified example, at least one of the inner packaging body 210 and the outer packaging body 220 is configured to have at least one of shock absorption, flame retardancy, cooling properties, and fire extinguishing properties.

In the energy storage device 100 of the first embodiment, one outer packaging body 220 may be configured to house multiple inner packaging bodies 210 in a state in which the energy storage device elements 120 are housed. In this modification, the sizes of the multiple inner packaging bodies 210 may be different or the same. According to this modification, the multiple energy storage device elements 120 can be connected in series or parallel, so that the voltage can be easily adjusted.

In the energy storage device 100 of embodiment 1, the packaging films 211, 212 for the energy storage device do not have to be transparent or gas permeable.

In the energy storage device 100 of the first embodiment, the inner packaging body 210 may be constructed by folding one energy storage device packaging film 211 and heat sealing the peripheral portion. Similarly, the outer packaging body 220 may be constructed by folding one exterior film 221 and heat sealing the peripheral portion.

The present disclosure will be described in detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the examples.

<Production of packaging film for electricity storage device according to first embodiment>
Example 1A
A polyethylene terephthalate (PET) film (thickness 12 μm) was prepared as the resin layer. An unstretched polypropylene film (CPP, thickness 50 μm) was prepared as the heat-sealable resin layer. The resin layer and the heat-sealable resin layer were bonded to each other by a dry lamination method using a two-liquid urethane adhesive containing carbon black (the average particle size of carbon black is within the range of 0.161 to 0.221 μm) so that the thickness of the adhesive layer after curing was 3 μm, and the resin layer and the heat-sealable resin layer were bonded to each other via a black adhesive layer. The black adhesive layer was used as a shielding layer. By the above procedure, a packaging film for a storage device was obtained in which the resin layer/adhesive layer (shielding layer)/heat-sealable resin layer were laminated in this order. The PP of the heat-sealable resin layer of Example 1A contains only erucic acid amide as a lubricant.

Example 2A
A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the resin layer. A polyethylene naphthalate (PEN) film (thickness 12 μm) was prepared as the substrate. A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the resin layer and the substrate via the adhesive layer by the dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, the substrate and the heat-sealable resin layer of the obtained laminate were bonded via the same adhesive layer. By the above procedure, a packaging film for a storage device was obtained in which the resin layer/adhesive layer/substrate/adhesive layer/heat-sealable resin layer were laminated in this order. The PPa of the resin layer and the heat-sealable resin layer of Example 2A each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 3A
A packaging film for an electricity storage device was obtained in the same manner as in Example 2A, except that a polyethylene terephthalate (PET) film (thickness 9 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer in Example 3A each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 4A
A packaging film for an electricity storage device was obtained in the same manner as in Example 3A, except that a polyethylene terephthalate (PET) film (thickness 12 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer in Example 4A each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 5A
A packaging film for an electricity storage device was obtained in the same manner as in Example 3A, except that a polyethylene terephthalate (PET) film (thickness 25 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer in Example 5A each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 6A
A packaging film for an electricity storage device was obtained in the same manner as in Example 4A, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 30 μm) was used as the resin layer, and a maleic anhydride-modified polypropylene (PPa) film (thickness 30 μm) was used as the heat-sealable resin layer. The resin layer and the PPa of the heat-sealable resin layer in Example 6A each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 7A
A packaging film for an electricity storage device was obtained in the same manner as in Example 4A, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 15 μm) was used as the resin layer, and a maleic anhydride-modified polypropylene (PPa) film (thickness 15 μm) was used as the heat-sealable resin layer. The resin layer and the PPa of the heat-sealable resin layer in Example 7A each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 8A
A polypropylene (PP) film (thickness 20 μm) was prepared as the resin layer. A polyethylene terephthalate (PET) film (thickness 12 μm) was prepared as the substrate. A polypropylene (PP) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the resin layer and the substrate via the adhesive layer by a dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, the substrate and the heat-sealable resin layer of the obtained laminate were bonded via the adhesive layer by a dry lamination method using a two-liquid urethane adhesive so that the thickness of the adhesive layer after curing was 1 μm or less. By the above procedure, a packaging film for a storage device in which the resin layer/adhesive layer/substrate/adhesive layer/heat-sealable resin layer were laminated in this order was obtained. The PP of the resin layer and the heat-sealable resin layer of Example 8A each contains only erucic acid amide as a lubricant.

Example 9A
Example 9A is the same as Example 4A, except that the PPa of the resin layer and the PPa of the heat-fusible resin layer each contain only erucic acid amide as a lubricant.

Example 10A
A packaging film for an electricity storage device was obtained in the same manner as in Example 4A, except that a polypropylene (PP) film (thickness 20 μm) was used as the resin layer, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PP and PPa of the resin layer and thermal adhesive resin layer of Example 10A each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 11A
A packaging film for a storage battery device was obtained in the same manner as in Example 9A, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was used as the resin layer, and a maleic anhydride-modified polyethylene (PEa) film (thickness 20 μm) was used as the heat-sealable resin layer. The resin layer and the heat-sealable resin layer PPa and PEa of Example 11A each contain only erucic acid amide as a lubricant.

Example 12A
A maleic anhydride-modified polypropylene (PPa) film (thickness 100 μm) was used as a packaging film for an electricity storage device consisting of only a heat-sealable resin layer. The PPa of the heat-sealable resin layer of Example 12A contained only erucic acid amide as a lubricant.

Example 13A
A polypropylene (PP) film (thickness 20 μm) was melt-extruded onto one side of an unstretched polypropylene (CPP) film (thickness 60 μm) as a substrate, and a maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was melt-extruded onto the other side of the CPP film to obtain a packaging film for an electricity storage device in which a resin layer/substrate/thermal adhesive resin layer were laminated in this order. The PP and PPa of the resin layer and the thermal adhesive resin layer of Example 13A each contained only erucic acid amide as a lubricant.

Example 14A
A triphenylmethane-4,4',4"-triisocyanate adhesion promoter (hereinafter referred to as T1) was applied in a solid content of 50 mg/ ^m2 on one side of a PET (12 μm) substrate that had been subjected to a corona discharge treatment on both sides, and then dried. Thereafter, a maleic anhydride-modified polypropylene (PPa) film (thickness 30 μm) to which 0.15 parts by weight of carbon black had been added was melt-extruded, and thereafter, T1 was applied in a solid content of 50 mg/ ^m2 on the other side of the PET (12 μm) and dried, and thereafter, a maleic anhydride-modified polypropylene (PPa) film (thickness 30 μm) to which 0.15 parts by weight of carbon black had been added was melt-extruded to obtain a packaging film for an electricity storage device.

Example 15A
A polymeric diphenylmethane diisocyanate adhesion promoter (hereinafter referred to as T2) was applied in a solid content of 50 mg/ ^m2 on one side of a PET (12 μm) substrate that had been subjected to a corona discharge treatment on both sides, and then dried. Thereafter, a polypropylene (PP) film (thickness: 30 μm) was melt-extruded. Thereafter, 50 mg/ ^m2 of T2 was applied in solid content on the other side of the PET (12 μm) and dried. Thereafter, a polypropylene (PP) film (thickness: 30 μm) was melt-extruded to obtain a packaging film for an electricity storage device.

Example 16A
A polypropylene (PP) film (thickness 30 μm) was prepared as the resin layer. A polyethylene terephthalate (PET) film (thickness 12 μm) was prepared as the substrate. A polypropylene (PP) film (thickness 30 μm) was prepared as the heat-sealable resin layer. A two-part adhesive consisting of a base material made of acid-modified polypropylene (PPa) and a curing agent made of isocyanurate was used to bond the resin layer and the substrate via the adhesive layer by the dry lamination method so that the thickness of the adhesive layer after curing was 3 μm. Furthermore, the substrate and the heat-sealable resin layer of the obtained laminate were bonded via the adhesive layer by the dry lamination method using a two-part adhesive consisting of a base material made of acid-modified polypropylene (PPa) and a curing agent made of isocyanurate so that the thickness of the adhesive layer after curing was 3 μm. By the above procedure, a packaging film for a storage device in which the resin layer/adhesive layer/substrate/adhesive layer/heat-sealable resin layer were laminated in this order was obtained. The resin layer and the PP of the heat-fusible resin layer in Example 16A each contained only erucic acid amide as a lubricant.

Comparative Example 1A
A stretched nylon (ONy) film (thickness 25 μm) was prepared as the base layer. An aluminum (ALM) foil (thickness 40 μm) was prepared as the barrier layer. A maleic anhydride modified polypropylene (PPa) was prepared as the adhesive layer. A polypropylene (PP) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the base layer and the barrier layer via the adhesive layer by a dry lamination method so that the thickness of the adhesive layer after curing was 3 μm. Furthermore, an adhesive layer (thickness 23 μm) and a heat-sealable resin layer (thickness 23 μm) were melt-extruded onto the surface of the barrier layer of the obtained laminate, to obtain an exterior material for a storage device in which the base layer/adhesive layer/barrier layer/adhesive layer/heat-sealable resin layer were laminated in this order. The PP of the heat-sealable resin layer of Comparative Example 1A contains two types of lubricants, erucic acid amide and behenic acid amide. The exterior packaging material for an electricity storage device of Comparative Example 1A can be suitably used as an outer packaging body.

Comparative Example 2A
A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the resin layer. Furthermore, an aluminum (ALM) foil (thickness 35 μm) was prepared as the barrier layer. Furthermore, maleic anhydride-modified polypropylene was prepared as the resin for forming the heat-sealable resin layer. Using a two-liquid urethane adhesive, the resin layer and the barrier layer were bonded via the adhesive layer by a dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, a heat-sealable resin layer (thickness 20 μm) was melt-extruded onto the surface of the barrier layer of the obtained laminate, and a packaging film for an electricity storage device in which the resin layer/adhesive layer/barrier layer/heat-sealable resin layer were laminated in this order was obtained as an example of an outer packaging body.

Comparative Example 3A
A polypropylene (PP) film (thickness 20 μm) was prepared as the resin layer. An aluminum (ALM) foil (thickness 35 μm) was prepared as the barrier layer. A polypropylene (PP) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the resin layer and the barrier layer via the adhesive layer by a dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, the substrate and the heat-sealable resin layer of the obtained laminate were bonded via the same adhesive layer. Through the above procedure, a packaging film for an electricity storage device was obtained as an example of an outer packaging body, in which a resin layer/adhesive layer/barrier layer/adhesive layer/heat-sealable resin layer were laminated in this order.

Comparative Example 4A
A packaging film for an electricity storage device was obtained as an example of an outer packaging body, in which a resin layer/adhesive layer/barrier layer/adhesive layer/thermal adhesive resin layer were laminated in this order, in the same manner as in Comparative Example 3A, except that a polypropylene (PP) film (thickness 10 μm) was used as the resin layer and a polypropylene (PP) film (thickness 10 μm) was used as the thermal adhesive resin layer. The PP of the resin layer and the thermal adhesive resin layer of Comparative Example 4A each contained two types of lubricants, erucic acid amide and behenic acid amide.

Comparative Example 5A
Comparative Example 5A is the same as Comparative Example 4A, except that the PP of the resin layer and the heat-fusible resin layer each contain only erucic acid amide as a lubricant.

<Measurement of _CO2 permeation amount>
The _CO2 permeation amount (cc·100 μm/ ^m2 /24 hr/atm) of the packaging film for electricity storage devices in an environment at a temperature of 30°C was measured by the following method, and the _CO2 permeability was evaluated according to the obtained _CO2 permeation amount according to the following criteria. In accordance with JIS K7126-1 (Plastics - Films and sheets - Gas permeability test method - Part 1: Differential pressure method), the permeation amount was measured by quantitatively analyzing the _CO2 that permeated through a φ60 mm of the packaging film for electricity storage devices 10 in an atmosphere at 30°C by gas chromatography. The results are shown in Table 1A. Note that the packaging films for electricity storage devices of Comparative Examples 1A to 5A had an ALM layer laminated thereon, so the _CO2 permeation amount in an environment at a temperature of 30°C was 0 cc·100 μm/ ^m2 /24 hr/atm.
A+: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 2000 cc·100 μm/m ² /24 hr/atm or more.
A: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 400 cc·100 μm/m ² /24 hr/atm or more and less than 2000 cc·100 μm/m ² /24 hr/atm.
B: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 200 cc·100 μm/m ² /24 hr/atm or more and less than 400 cc·100 cc·100 μm/m ² /24 hr/atm.
C: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 100 cc·100 μm/m ² /24 hr/atm or more and less than 200 cc·100 μm/m ² /24 hr/atm.
D: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 0 cc·100 μm/m ² /24 hr/atm or more and less than 100 cc·100 μm/m ² /24 hr/atm.

In Table 1A, "≦1 μm" indicates 1 μm or less. In addition, the "/" in the layered structure shown in Table 1A indicates the separation of layers. In addition, the numbers (μm) in parentheses indicate the thickness of the layers.

The packaging films for electricity storage devices of Examples 1A to 13A are packaging films for electricity storage devices that have at least a heat-sealable resin layer, and have a CO ₂ permeation amount of 100 cc·100 μm/m ² /24 hr/atm or more in a temperature 30° C. environment. Therefore, when a packaging body made of the packaging film for electricity storage devices is used to seal an electricity storage device element, gas (especially CO ₂ ) generated from the electricity storage device can be suitably released to the outside. Furthermore, the packaging films for electricity storage devices of Examples 1A to 13A can be suitably used as packaging films that directly package electricity storage device elements. For example, in an electricity storage device 30 in which an electricity storage device element 32 is housed in a double-structure packaging body having an inner packaging body 10a and an outer packaging body 20 as shown in FIG. 7, the packaging film for electricity storage devices 10 of the present disclosure can be suitably used to form the inner packaging body 10a. For example, by using the electricity storage device packaging film 10 of the present disclosure as the inner packaging body 10a, sealing an electricity storage device element in the inner packaging body 10a before housing it in the outer packaging body 20, and performing an initial charge/discharge process and an aging process, it is possible to suitably release gas (particularly CO ₂ ) generated from the electricity storage device element to the outside during these processes. This makes it unnecessary to provide a space for retaining gas inside the temporarily sealed electricity storage device packaging film, as in the case of using a conventional electricity storage device exterior material having a barrier layer, and furthermore to use an electricity storage device packaging film that is larger than the size required for the final electricity storage device product (for example, more than twice the size required to seal the electricity storage device element) in order to remove the space that retains the gas and release the gas to the outside.

In addition, the packaging film for the electricity storage device in Example 1A does not have a metal layer formed from metal, but it is believed that the inclusion of a shielding layer makes the electricity storage device elements, which have a complex shape, less visible and thus prevents counterfeiting.

The packaging films for electricity storage devices of Examples 2A to 7A and Examples 9A to 13A have adhesive properties to metals and do not have a metal layer formed of metal. Since the packaging films for electricity storage devices of Examples 2A to 7A and Examples 9A to 13A have adhesive properties to metals, they can be suitably attached to, for example, metal terminals. That is, the packaging films for electricity storage devices of Examples 2A to 7A and Examples 9A to 13A can be suitably used as packaging films that directly package electricity storage device elements by adhering them to metal terminals. For example, in an electricity storage device 30 in which an electricity storage device element 32 is housed in a double-structure packaging body having an inner packaging body 10a and an outer packaging body 20 as shown in Figures 6 and 7, the packaging film for electricity storage devices 10 of the present disclosure can be suitably used to form the inner packaging body 10a. Since the metal terminal and the heat-sealable resin layer of the packaging film are made of different materials, generally, the adhesion is likely to decrease at the interface between the metal terminal and the heat-sealable resin layer. For this reason, an adhesive film is generally placed between the metal terminal and the heat-sealable resin layer of the packaging film, but the packaging film for an electricity storage device disclosed herein has adhesive properties to metal, so the electricity storage device element can be sealed while adhering to the metal terminal without using such an adhesive film. In addition, Comparative Examples 1 to 5 can be suitably used as the outer packaging body 20.

<Continuous battery production>
Furthermore, when the packaging films for electricity storage devices obtained in Examples 1A to 13A and Comparative Examples 1A to 5A were subjected to cold forming using a mold, the packaging films for electricity storage devices of Examples 2A to 7A, 10A and Comparative Examples 1A and 4A, which used two types of lubricants, erucic acid amide and behenic acid amide, for the resin layer and/or heat-sealable resin layer, suppressed adhesion of the lubricant to the mold, thereby reducing the frequency of cleaning the mold and showing superior continuous productivity of the packaging films for electricity storage devices, compared with Examples 1A, 8A, 11A to 13A and Comparative Examples 2A, 3A, and 5A, which used only erucic acid amide as the lubricant for the resin layer and/or heat-sealable resin layer. In Table 1A, Examples and Comparative Examples which were superior in continuous productivity of batteries were given an evaluation of A, and those which were inferior to Evaluation A were given an evaluation of B.

<Production of packaging film for electricity storage device according to second embodiment>
Example 1B
A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the resin layer. A polyethylene naphthalate (PEN) film (thickness 12 μm) was prepared as the substrate. A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the resin layer and the substrate via the adhesive layer by the dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, the substrate and the heat-sealable resin layer of the obtained laminate were bonded via the same adhesive layer. By the above procedure, a packaging film for a storage device was obtained in which the resin layer/adhesive layer/substrate/adhesive layer/heat-sealable resin layer were laminated in this order. The PPa of the resin layer and the heat-sealable resin layer of Example 1B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 2B
A packaging film for an electricity storage device was obtained in the same manner as in Example 1B, except that a polyethylene terephthalate (PET) film (thickness 9 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer in Example 2B each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 3B
A packaging film for an electricity storage device was obtained in the same manner as in Example 1B, except that a polyethylene terephthalate (PET) film (thickness 12 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer in Example 3B each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 4B
A packaging film for an electricity storage device was obtained in the same manner as in Example 1B, except that a polyethylene terephthalate (PET) film (thickness 25 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the B resin layer and the thermal adhesive resin layer of Example 4B each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 5B
A packaging film for an electricity storage device was obtained in the same manner as in Example 3B, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 30 μm) was used as the resin layer, and a maleic anhydride-modified polypropylene (PPa) film (thickness 30 μm) was used as the heat-sealable resin layer. The resin layer and the PPa of the heat-sealable resin layer in Example 5B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 6B
A packaging film for a storage battery device was obtained in the same manner as in Example 3B, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 15 μm) was used as the resin layer, and a maleic anhydride-modified polypropylene (PPa) film (thickness 15 μm) was used as the heat-sealable resin layer. The resin layer and the PPa of the heat-sealable resin layer in Example 6B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 7B
Example 7B is the same as Example 3B, except that the PPa of the resin layer and the PPa of the heat-fusible resin layer each contain only erucic acid amide as a lubricant.

Example 8B
A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the resin layer. A polyethylene terephthalate (PET) film (thickness 12 μm) was prepared as the substrate. A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive containing carbon black (the average particle size of carbon black is within the range of 0.161 to 0.221 μm) was used to bond the resin layer and the substrate via the adhesive layer by the dry lamination method so that the thickness of the adhesive layer after curing was 3 μm. Furthermore, the substrate and the heat-sealable resin layer of the obtained laminate were bonded via the adhesive layer by the dry lamination method using a two-liquid urethane adhesive so that the thickness of the adhesive layer after curing was 1 μm or less. The black adhesive layer between the resin layer and the substrate was used as the shielding layer. By the above procedure, a packaging film for an electricity storage device was obtained in which the resin layer/adhesive layer (shielding layer)/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer of Example 8B each contained only erucic acid amide as a lubricant.

Example 9B
A packaging film for an electricity storage device was obtained in the same manner as in Example 3B, except that a polypropylene (PP) film (thickness 20 μm) containing carbon black (average particle size of carbon black is in the range of 0.161 to 0.221 μm) was used as the resin layer, and a maleic anhydride modified polypropylene (PPa) film (thickness 20 μm) was used as the heat-sealable resin layer. The PP and PPa of the resin layer and heat-sealable resin layer of Example 9B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 10B
A packaging film for an electricity storage device was obtained in the same manner as in Example 9B, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) containing carbon black (average particle size of carbon black is in the range of 0.161 to 0.221 μm) was used as the resin layer, and a maleic anhydride-modified polyethylene (PEa) film (thickness 20 μm) was used as the heat-sealable resin layer. The resin layer and the heat-sealable resin layer PPa and PEa of Example 10B each contain only erucic acid amide as a lubricant.

Example 11B
A maleic anhydride-modified polypropylene (PPa) film (thickness 100 μm) containing carbon black (average particle size of carbon black is within the range of 0.161 to 0.221 μm) was used as a packaging film for an electricity storage device consisting of only a heat-sealable resin layer. The PPa of the heat-sealable resin layer of Example 11B contains only erucic acid amide as a lubricant.

Example 12B
A polypropylene (PP) film (20 μm thick) containing carbon black (the average particle size of carbon black is within the range of 0.161 to 0.221 μm) was melt-extruded onto one side of an unstretched polypropylene (CPP) film (60 μm thick) as a substrate, and a maleic anhydride-modified polypropylene (PPa) film (20 μm thick) was melt-extruded onto the other side of the CPP film to obtain a packaging film for an electricity storage device in which a resin layer (shielding layer)/substrate/thermal adhesive resin layer were laminated in this order. The PP and PPa of the resin layer and the thermal adhesive resin layer of Example 12B each contained only erucic acid amide as a lubricant.

Comparative Example 1B
A polyethylene terephthalate (PET) film (thickness 12 μm) was prepared as the resin layer. An unstretched polypropylene film (CPP, thickness 50 μm) was prepared as the heat-sealable resin layer. The resin layer and the heat-sealable resin layer were bonded to each other by a dry lamination method using a two-liquid urethane adhesive containing carbon black (the average particle size of carbon black is within the range of 0.161 to 0.221 μm) so that the thickness of the adhesive layer after curing was 3 μm, and the resin layer and the heat-sealable resin layer were bonded to each other via a black adhesive layer. The black adhesive layer was used as a shielding layer. By the above procedure, a packaging film for a storage device was obtained in which the resin layer/adhesive layer (shielding layer)/heat-sealable resin layer were laminated in this order. The PP of the heat-sealable resin layer of Comparative Example 1B contains only erucic acid amide as a lubricant.

Comparative Example 2B
A packaging film for an electricity storage device was obtained in the same manner as in Example 8B, except that a polypropylene (PP) film (thickness 20 μm) was used as the resin layer and a polypropylene (PP) film (thickness 20 μm) was used as the heat-sealable resin layer, in which a resin layer/adhesive layer (shielding layer)/substrate/adhesive layer/heat-sealable resin layer were laminated in this order. The resin layer and the PP of the heat-sealable resin layer in Comparative Example 2B each contained two types of lubricants, erucic acid amide and behenic acid amide.

Comparative Example 3B
A polypropylene (PP) film (thickness 20 μm) was prepared as the resin layer. A polyethylene terephthalate (PET) film (thickness 12 μm) was prepared as the substrate. A polypropylene (PP) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the resin layer and the substrate via the adhesive layer by dry lamination so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, a heat-sealable resin layer was melt-extruded onto the surface of the substrate of the obtained laminate to obtain a packaging film for a storage device in which the resin layer/adhesive layer/substrate/heat-sealable resin layer were laminated in this order. The PP of the resin layer and the heat-sealable resin layer of Comparative Example 3B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Comparative Example 4B
A polypropylene (PP) film (thickness 20 μm) was prepared as the resin layer. An aluminum (ALM) foil (thickness 35 μm) was prepared as the barrier layer. A polypropylene (PP) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the resin layer and the barrier layer via the adhesive layer by a dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, a two-liquid urethane adhesive was used to bond the barrier layer side of the obtained laminate and the heat-sealable resin layer via the adhesive layer by a dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Through the above procedure, a packaging film for an electricity storage device was obtained as an example of an outer packaging body, in which a resin layer/adhesive layer/barrier layer/adhesive layer/heat-sealable resin layer were laminated in this order. The PP of the resin layer and the heat-sealable resin layer of Comparative Example 4B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Comparative Example 5B
Except for using a polypropylene (PP) film (thickness 10 μm) as the resin layer and a polypropylene (PP) film (thickness 10 μm) as the heat-sealable resin layer, a packaging film for an electricity storage device in which a resin layer/adhesive layer/barrier layer/adhesive layer/heat-sealable resin layer were laminated in this order was obtained as an example of an outer packaging body in the same manner as in Comparative Example 4. The PP of the resin layer and the heat-sealable resin layer in Comparative Example 5B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Comparative Example 6B
Comparative Example 6 is the same as Comparative Example 5B, except that the PP of the resin layer and the heat-fusible resin layer each contain only erucic acid amide as a lubricant.

<Total light transmittance>
The total light transmittance of the packaging film for electricity storage devices was measured in the visible light region (400 to 700 nm) using a UV-Vis-Near-Infrared Spectrophotometer V-670 manufactured by JASCO Corporation in accordance with the measurement method specified in JIS K7361-1:1997, and the average value was taken as the total light transmittance. The measurement conditions were as follows: a halogen lamp was used as the light source, UV/Vis bandwidth: 5.0 nm, scanning speed: 1000 nm/min, response: Medium, data acquisition interval: 1.0 nm. The results are shown in Table 1B.

<Shielding evaluation>
A paper was prepared on which the letter "A" was printed in black using a laser printer with a font of Arial, a font size of 36, and a line thickness of about 1 mm. In an indoor lighting environment (300 to 500 lux), the paper on which the letter "A" was written was placed under a packaging film for a power storage device. The letter "A" was visually observed through the packaging film for a power storage device from a distance of 30 cm in front of the packaging film for a power storage device. The visibility of the letter was evaluated for shielding ability using the following criteria of levels 1 to 5. The results are shown in Table 1B.
Level 1: Easy to see.
Level 2: It is a little difficult to see, but the letters can be recognised.
Level 3: Difficult to see, but can recognize letters.
Level 4: Very difficult to see, but letters can be vaguely discerned.
Level 5: I can't see the letters.

In Table 1B, "≦1 μm" indicates 1 μm or less. In addition, the "/" in the layered structure shown in Table 1B indicates the separation of layers. In addition, the numbers (μm) in parentheses indicate the thickness of the layers.

The packaging films for electricity storage devices of Examples 1B to 12B have adhesiveness to metals and do not have a metal layer formed of metal. Since the packaging films for electricity storage devices of Examples 1B to 12B have adhesiveness to metals, they can be suitably attached to, for example, metal terminals. That is, the packaging films for electricity storage devices of Examples 1B to 12B can be suitably used as packaging films that directly package electricity storage device elements by adhering them to metal terminals. For example, in an electricity storage device 30 in which an electricity storage device element 32 is housed in a double-structure packaging body having an inner packaging body 10a and an outer packaging body 20 as shown in FIG. 7, the packaging film for electricity storage devices 10 of the present disclosure can be suitably used to form the inner packaging body 10a. Since the metal terminal and the heat-sealable resin layer of the packaging film are made of different materials, generally, the adhesion is likely to decrease at the interface between the metal terminal and the heat-sealable resin layer. For this reason, an adhesive film is generally placed between the metal terminal and the heat-sealable resin layer of the packaging film, but the packaging film for an electricity storage device disclosed herein has adhesive properties to metal, so the electricity storage device element can be sealed while adhering to the metal terminal without using such an adhesive film. Comparative Examples 4B to 6B can also be suitably used as the outer packaging body 20.

The packaging films for electricity storage devices in Examples 8B to 12B do not have a metal layer formed from metal, but because they have a shielding layer, they have the effect of shielding even the very simple letter A, making it difficult to see. Therefore, it is believed that the inclusion of a shielding layer makes electricity storage device elements with complex shapes difficult to see, and thus inhibits counterfeiting.

<Continuous battery production>
Furthermore, when the packaging films for electricity storage devices obtained in Examples 1B to 12B and Comparative Examples 1B to 6B were subjected to cold molding using a mold, the packaging films for electricity storage devices of Examples 1B to 6B and 9B and Comparative Examples 2B to 5B, which used two types of lubricants, erucic acid amide and behenic acid amide, for the resin layer and/or heat-sealable resin layer, suppressed adhesion of the lubricant to the mold, thereby reducing the frequency of cleaning the mold and showing superior continuous productivity of the packaging films for electricity storage devices, compared with Examples 7B to 8B, 10B to 12B and Comparative Examples 1B and 6B, which used only erucic acid amide as the lubricant for the resin layer and/or heat-sealable resin layer. In Table 1B, Examples and Comparative Examples with superior continuous productivity of batteries were rated A, and those with inferior productivity to Rating A were rated B.

<Production of packaging film for electricity storage device according to second embodiment>
Example 13B
A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the resin layer. A polyethylene naphthalate (PEN) film (thickness 12 μm) was prepared as the substrate. A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the resin layer and the substrate via the adhesive layer by the dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, the substrate and the heat-sealable resin layer of the obtained laminate were bonded via the same adhesive layer. By the above procedure, a packaging film for a storage device was obtained in which the resin layer/adhesive layer/substrate/adhesive layer/heat-sealable resin layer were laminated in this order. The PPa of the resin layer and the heat-sealable resin layer of Example 13B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 14B
A packaging film for an electricity storage device was obtained in the same manner as in Example 13B, except that a polyethylene terephthalate (PET) film (thickness 9 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer of Example 14B each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 15B
A packaging film for an electricity storage device was obtained in the same manner as in Example 14B, except that a polyethylene terephthalate (PET) film (thickness 12 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer of Example 15B each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 16B
A packaging film for an electricity storage device was obtained in the same manner as in Example 14B, except that a polyethylene terephthalate (PET) film (thickness 25 μm) was used as the substrate, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PPa of the resin layer and the thermal adhesive resin layer of Example 16B each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 17B
A packaging film for a storage battery device was obtained in the same manner as in Example 15B, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 30 μm) was used as the resin layer, and a maleic anhydride-modified polypropylene (PPa) film (thickness 30 μm) was used as the heat-sealable resin layer. The resin layer and the PPa of the heat-sealable resin layer in Example 17B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 18B
A packaging film for a storage battery device was obtained in the same manner as in Example 15B, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 15 μm) was used as the resin layer, and a maleic anhydride-modified polypropylene (PPa) film (thickness 15 μm) was used as the heat-sealable resin layer. The resin layer and the PPa of the heat-sealable resin layer in Example 18B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Example 19B
Example 19B is the same as Example 15B, except that the PPa of the resin layer and the PPa of the heat-fusible resin layer each contain only erucic acid amide as a lubricant.

Example 20B
A packaging film for an electricity storage device was obtained in the same manner as in Example 15B, except that a polypropylene (PP) film (thickness 20 μm) was used as the resin layer, in which a resin layer/adhesive layer/substrate/adhesive layer/thermal adhesive resin layer were laminated in this order. The PP and PPa of the resin layer and the thermal adhesive resin layer of Example 20B each contained two types of lubricants, erucic acid amide and behenic acid amide.

Example 21B
A packaging film for a storage battery device was obtained in the same manner as in Example 19B, except that a maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was used as the resin layer, and a maleic anhydride-modified polyethylene (PEa) film (thickness 20 μm) was used as the heat-sealable resin layer. The resin layer and the heat-sealable resin layer PPa and PEa of Example 21B each contain only erucic acid amide as a lubricant.

Example 22B
A maleic anhydride modified polypropylene (PPa) film (thickness 100 μm) was used as a packaging film for an electricity storage device consisting of only a heat-sealable resin layer. The PPa of the heat-sealable resin layer of Example 22B contains only erucic acid amide as a lubricant.

Example 23B
A polypropylene (PP) film (20 μm thick) was melt-extruded onto one side of an unstretched polypropylene (CPP) film (60 μm thick) as a substrate, and a maleic anhydride-modified polypropylene (PPa) film (20 μm thick) was melt-extruded onto the other side of the CPP film to obtain a packaging film for an electricity storage device in which a resin layer/substrate/thermal adhesive resin layer were laminated in this order. The PP and PPa of the resin layer and the thermal adhesive resin layer of Example 23B each contained only erucic acid amide as a lubricant.

Comparative Example 7B
As the base layer, an oriented nylon (ONy) film (thickness 25 μm) was prepared. As the barrier layer, an aluminum (ALM) foil (thickness 40 μm) was prepared. As the adhesive layer, a maleic anhydride modified polypropylene (PPa) was prepared. As the heat-sealable resin layer, polypropylene (PP) was prepared. Using a two-liquid urethane adhesive, the thickness of the adhesive layer after curing was 3 μm, and the base layer and the barrier layer were bonded via the adhesive layer by a dry lamination method. Furthermore, an adhesive layer (thickness 23 μm) and a heat-sealable resin layer (thickness 23 μm) were melt-extruded onto the surface of the barrier layer of the obtained laminate, to obtain an exterior material for a storage battery device in which the base layer/adhesive layer/barrier layer/adhesive layer/heat-sealable resin layer were laminated in this order. The PP of the heat-sealable resin layer of Comparative Example 7 contains two types of lubricants, erucic acid amide and behenic acid amide. The exterior material for a storage battery device of Comparative Example 7B can be suitably used as an outer packaging body.

Comparative Example 8B
A maleic anhydride-modified polypropylene (PPa) film (thickness 20 μm) was prepared as the resin layer. Furthermore, an aluminum (ALM) foil (thickness 35 μm) was prepared as the barrier layer. Furthermore, maleic anhydride-modified polypropylene was prepared as the resin for forming the heat-sealable resin layer. Using a two-liquid urethane adhesive, the resin layer and the barrier layer were bonded via the adhesive layer by a dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, a heat-sealable resin layer (thickness 20 μm) was melt-extruded onto the surface of the barrier layer of the obtained laminate, and a packaging film for an electricity storage device in which the resin layer/adhesive layer/barrier layer/heat-sealable resin layer were laminated in this order was obtained as an example of an outer packaging body.

Comparative Example 9B
A polypropylene (PP) film (thickness 20 μm) was prepared as the resin layer. An aluminum (ALM) foil (thickness 35 μm) was prepared as the barrier layer. A polypropylene (PP) film (thickness 20 μm) was prepared as the heat-sealable resin layer. A two-liquid urethane adhesive was used to bond the resin layer and the barrier layer via the adhesive layer by a dry lamination method so that the thickness of the adhesive layer after curing was 1 μm or less. Furthermore, the substrate and the heat-sealable resin layer of the obtained laminate were bonded via the same adhesive layer. Through the above procedure, a packaging film for an electricity storage device was obtained as an example of an outer packaging body, in which a resin layer/adhesive layer/barrier layer/adhesive layer/heat-sealable resin layer were laminated in this order.

Comparative Example 10B
A packaging film for an electricity storage device was obtained as an example of an outer packaging body in which a resin layer/adhesive layer/barrier layer/adhesive layer/thermal adhesive resin layer were laminated in this order in the same manner as in Comparative Example 3B, except that a polypropylene (PP) film (thickness 10 μm) was used as the resin layer and a polypropylene (PP) film (thickness 10 μm) was used as the thermal adhesive resin layer. The PP of the resin layer and the thermal adhesive resin layer of Comparative Example 10B each contain two types of lubricants, erucic acid amide and behenic acid amide.

Comparative Example 11B
Comparative Example 11B is the same as Comparative Example 10B, except that the PP of the resin layer and the heat-fusible resin layer each contain only erucic acid amide as a lubricant.

<Measurement of _CO2 permeation amount>
The _CO2 permeation amount (cc·100 μm/ ^m2 /24 hr/atm) of the packaging film for electricity storage devices in an environment at a temperature of 30°C was measured by the following method, and the _CO2 permeability was evaluated according to the obtained _CO2 permeation amount according to the following criteria. In accordance with JIS K7126-1 (Plastics - Films and Sheets - Gas Permeability Test Method - Part 1: Differential Pressure Method), the permeation amount was measured by quantitatively analyzing the _CO2 that permeated through the φ60 mm of the packaging film for electricity storage devices 10 in an atmosphere at 30°C by gas chromatography. The results are shown in Table 2B. Note that the packaging films for electricity storage devices of Comparative Examples 7 to 11 had an ALM layer laminated thereon, and therefore the _CO2 permeation amount in an environment at a temperature of 30°C was 0 cc·100 μm/ ^m2 /24 hr/atm.
A+: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 2000 cc·100 μm/m ² /24 hr/atm or more.
A: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 400 cc·100 μm/m ² /24 hr/atm or more and less than 2000 cc·100 μm/m ² /24 hr/atm.
B: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 200 cc·100 μm/m ² /24 hr/atm or more and less than 400 cc·100 cc·100 μm/m ² /24 hr/atm.
C: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 100 cc·100 μm/m ² /24 hr/atm or more and less than 200 cc·100 μm/m ² /24 hr/atm.
D: The CO ₂ permeation amount in an environment at a temperature of 30° C. is 0 cc·100 μm/m ² /24 hr/atm or more and less than 100 cc·100 μm/m ² /24 hr/atm.

In Table 2B, "≦1 μm" indicates 1 μm or less. In addition, the "/" in the layered structure shown in Table 2B indicates the separation of layers. In addition, the numbers (μm) in parentheses indicate the thickness of the layers.

The packaging films for electricity storage devices of Examples 13B to 23B are packaging films for electricity storage devices that have at least a heat-sealable resin layer, and have a CO ₂ permeation amount of 100 cc·100 μm/m ² /24 hr/atm or more in a temperature 30° C. environment. Therefore, when a packaging body made of the packaging film for electricity storage devices is used to seal an electricity storage device element, gas (especially CO ₂ ) generated from the electricity storage device can be suitably released to the outside. In addition, the packaging films for electricity storage devices of Examples 13B to 23B can be suitably used as packaging films that directly package electricity storage device elements. For example, in an electricity storage device 30 in which an electricity storage device element 32 is housed in a double-structure packaging body having an inner packaging body 10a and an outer packaging body 20 as shown in FIG. 7, the packaging film for electricity storage devices 10 of the present disclosure can be suitably used to form the inner packaging body 10a. For example, by using the electricity storage device packaging film 10 of the present disclosure as the inner packaging body 10a, sealing an electricity storage device element in the inner packaging body 10a before housing it in the outer packaging body 20, and performing an initial charge/discharge process and an aging process, it is possible to suitably release gas (particularly CO ₂ ) generated from the electricity storage device element to the outside during these processes. This makes it unnecessary to provide a space for retaining gas inside the temporarily sealed electricity storage device packaging film, as in the case of using a conventional electricity storage device exterior material having a barrier layer, and furthermore to use an electricity storage device packaging film that is larger than the size required for the final electricity storage device product (for example, more than twice the size required to seal the electricity storage device element) in order to remove the space that retains the gas and release the gas to the outside.

The packaging films for electricity storage devices of Examples 13B to 23B have adhesive properties to metals and do not have a metal layer formed of metal. Since the packaging films for electricity storage devices of Examples 13B to 23B have adhesive properties to metals, they can be suitably attached to, for example, metal terminals. That is, the packaging films for electricity storage devices of Examples 13B to 23B can be suitably used as packaging films that directly package electricity storage device elements by adhering them to metal terminals. For example, in an electricity storage device 30 in which an electricity storage device element 32 is housed in a double-structure packaging body having an inner packaging body 10a and an outer packaging body 20 as shown in Figures 6 and 7, the packaging film for electricity storage devices 10 of the present disclosure can be suitably used to form the inner packaging body 10a. Since the metal terminal and the heat-sealable resin layer of the packaging film are made of different materials, generally, the adhesion is likely to decrease at the interface between the metal terminal and the heat-sealable resin layer. For this reason, an adhesive film is generally placed between the metal terminal and the heat-sealable resin layer of the packaging film, but the packaging film for an electricity storage device disclosed herein has adhesive properties to metal, so the electricity storage device element can be sealed while adhering to the metal terminal without using such an adhesive film. In addition, Comparative Examples 7B to 11B can be suitably used as the outer packaging body 20.

As described above, the first aspect of the present disclosure provides the invention having the following aspects.
Item 1A. A packaging film for an electricity storage device comprising at least a heat-sealable resin layer,
A packaging film for an electricity storage device, having a _CO2 permeation amount of 100 cc·100 μm/ ^m2 /24 hr/atm or more in an environment at a temperature of 30°C.
Item 2A. The packaging film for an electricity storage device according to Item 1A, which is constituted by a laminate including, in order from the outside, at least a resin layer and the heat-sealable resin layer.
Item 3A. The packaging film for an electricity storage device according to Item 2A, which is constituted by a laminate including, in order from the outside, at least the resin layer, a substrate, and the heat-sealable resin layer.
Item 4A. The packaging film for an electricity storage device according to Item 3A, which is constituted by a laminate including, in order from the outside, at least the resin layer, the adhesive layer, the base material, and the heat-sealable resin layer.
Item 5A. The packaging film for a storage battery device according to Item 4A, which is composed of a laminate including, in order from the outside, at least the resin layer, the adhesive layer, the base material, an adhesive layer, and the heat-sealable resin layer.
Item 6A. The packaging film for a storage battery device according to any one of Items 2A to 5A, wherein an outer surface of the resin layer has adhesion to metal.
Item 7A. The packaging film for an electricity storage device according to any one of Items 1A to 6A, wherein an inner surface of the heat-sealable resin layer has adhesion to metal.
Item 8A. An electricity storage device, in which an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the packaging film for electricity storage devices according to any one of Items 1A to 7A.
Item 9A. An electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is contained in an inner packaging body formed from the packaging film for electricity storage devices according to any one of Items 1A to 7A,
The power storage device, wherein the inner packaging is further contained within an outer packaging.
Item 10A. The electricity storage device according to Item 9A, wherein the outer packaging body has a metal layer formed of a metal.
Item 11A. The electricity storage device according to any one of Items 8A to 10A, wherein the packaging film for the electricity storage device is in contact with a metal terminal electrically connected to the positive electrode or the negative electrode.
Item 12A. A method for producing a packaging film for an electricity storage device, comprising at least a step of providing a heat-sealable resin layer,
A method for producing _a packaging film for an electricity storage device, the method comprising the steps of: ( ^a ) forming a packaging film for a storage device;

As described above, the second aspect of the present disclosure provides the invention having the following aspects.
Item 1B. A packaging film for an electricity storage device comprising at least a heat-sealable resin layer,
The packaging film for an electricity storage device has adhesiveness to metal,
The packaging film for an electricity storage device does not have a metal layer formed from a metal.
Item 2B: The packaging film for an electricity storage device according to Item 1B, which is constituted by a laminate including, in order from the outside, at least a resin layer and the heat-sealable resin layer.
Item 3B: The packaging film for an electricity storage device according to Item 2B, which is constituted by a laminate including, in order from the outside, at least the resin layer, a substrate, and the heat-sealable resin layer.
Item 4B: The packaging film for an electricity storage device according to Item 3B, which is constituted by a laminate including, in order from the outside, at least the resin layer, the adhesive layer, the base material, and the heat-sealable resin layer.
Item 5B. The packaging film for a storage battery device according to Item 4B, which is constituted by a laminate including, in order from the outside, at least the resin layer, the adhesive layer, the base material, an adhesive layer, and the heat-sealable resin layer.
Item 6B: The packaging film for a storage battery device according to any one of Items 2B to 5B, wherein an outer surface of the resin layer has adhesion to metal.
Item 7B: The packaging film for an electricity storage device according to any one of Items 1B to 6B, wherein an inner surface of the heat-sealable resin layer has adhesion to metal.
Item 8B: The packaging film for an electricity storage device according to any one of Items 1B to 7B, wherein the CO ₂ permeation amount in an environment at a temperature of 30° C. is 100 cc·100 μm/m ² /24 hr/atm or more.
Item 9B: An electricity storage device, in which an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the packaging film for electricity storage devices according to any one of Items 1B to 8B.
Item 10B. An electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is contained in an inner packaging body formed from the packaging film for electricity storage devices according to any one of items 1B to 8B,
The power storage device, wherein the inner packaging is further contained within an outer packaging.
Item 11B. The electricity storage device according to Item 10B, wherein the outer packaging body has a metal layer formed of a metal.
Item 12B: The electricity storage device according to any one of Items 9B to 10B, wherein the electricity storage device packaging film is in contact with a metal terminal electrically connected to the positive electrode or the negative electrode.
Item 13B. A method for producing a packaging film for an electricity storage device, comprising at least a step of providing a heat-sealable resin layer,
The packaging film for an electricity storage device has adhesiveness to metal,
The packaging film for an electricity storage device does not have a metal layer formed from a metal,

As described above, the third aspect of the present disclosure provides the invention having the following aspects.
Item 1C. A method for producing an electricity storage device,
The power storage device is
An electricity storage device element;
and an inner packaging body that houses the electricity storage device element,
the inner packaging body is made of a transparent packaging film for an electricity storage device,
an inner wrapping step of wrapping the electricity storage device element with the electricity storage device packaging film;
an inner sealing step, which is carried out after the inner wrapping step, of sealing the packaging film for the electricity storage device such that the electricity storage device element is hermetically sealed by the packaging film for the electricity storage device.
Item 2C. The packaging film for an electricity storage device further has gas permeability,
Item 1D, the method for producing an electricity storage device according to Item 1C, further comprising a degassing step, which is carried out after the inner sealing step, of releasing gas generated from the electricity storage device elements through the electricity storage device packaging film.
Item 3C. The method for producing an electricity storage device according to Item 2C, wherein in the inner wrapping step, the electricity storage device element is wrapped in the electricity storage device packaging film having substantially the same size as the inner wrapping body of a completed electricity storage device.
Item 4C. A power storage device element,
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed therein;
The inner packaging body is formed of a transparent packaging film for an electricity storage device.
Item 5C. A metal terminal electrically connected to the electricity storage device element;
a tab film disposed between the inner wrapper and the metal terminal,
The outer wrapper is joined to the inner wrapper,
the inner wrapping body and the metal terminal are joined via the tab film,
Item 4D. The electricity storage device according to item 4C, wherein at least a part of an outer edge of the inner wrapping body is exposed from the outer wrapping body.
Item 6C. A metal terminal electrically connected to the electricity storage device element;
a tab film disposed between the inner wrapping body and the metal terminal, and between the outer wrapping body and the metal terminal;
the inner wrapping body and the outer wrapping body are joined to the metal terminal via the tab film,
Item 4D. The electricity storage device according to item 4C, wherein the inner packaging body is entirely covered by the outer packaging body.
Item 7C. Further comprising a metal terminal electrically connected to the electricity storage device element,
The inner packaging body and the metal terminal are joined together,
Item 4D. The electricity storage device according to item 4C, wherein at least a part of an outer edge of the inner wrapping body is exposed from the outer wrapping body.
Item 8C. Further comprising a metal terminal electrically connected to the electricity storage device element,
the inner wrapping body and the outer wrapping body are joined to the metal terminal,
Item 4D. The electricity storage device according to item 4C, wherein the inner packaging body is entirely covered by the outer packaging body.
Item 9C: The electricity storage device according to any one of Items 3C to 8C, wherein the packaging film for the electricity storage device further has gas permeability.

As described above, the fourth aspect of the present disclosure provides the invention having the following aspects.
Item 1D. A method for manufacturing an electricity storage device,
The power storage device is
An electricity storage device element;
and an inner packaging body that houses the electricity storage device element,
the inner packaging body is composed of a gas-permeable packaging film for an electricity storage device,
an inner wrapping step of wrapping the electricity storage device element with the electricity storage device packaging film;
an inner sealing step, which is carried out after the inner wrapping step, of sealing the packaging film for the electricity storage device so that the electricity storage device element is hermetically sealed by the packaging film for the electricity storage device;
a degassing step, which is carried out after the inner sealing step, of releasing gas generated from the electricity storage device elements through the electricity storage device packaging film.
Item 2D. The method for producing an electricity storage device according to Item 1D, wherein in the inner wrapping step, the electricity storage device element is wrapped in the electricity storage device packaging film having substantially the same size as the inner wrapping body of a completed electricity storage device.
Item 3D. A power storage device element;
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed therein;
The electricity storage device, wherein the inner packaging body is constituted by a gas-permeable packaging film for an electricity storage device.
Item 4D. A metal terminal electrically connected to the electricity storage device element;
a tab film disposed between the inner wrapper and the metal terminal,
The outer wrapper is joined to the inner wrapper,
the inner wrapping body and the metal terminal are joined via the tab film,
Item 3D. The electricity storage device according to item 3D, wherein at least a portion of an outer edge of the inner wrapping body is exposed from the outer wrapping body.
Item 5D. A metal terminal electrically connected to the electricity storage device element;
a tab film disposed between the inner wrapping body and the metal terminal, and between the outer wrapping body and the metal terminal;
the inner wrapping body and the outer wrapping body are joined to the metal terminal via the tab film,
Item 3D. The electricity storage device according to item 3D, wherein the inner packaging body is entirely covered by the outer packaging body.
Item 6D. Further comprising a metal terminal electrically connected to the electricity storage device element,
The inner packaging body and the metal terminal are joined together,
Item 3D. The electricity storage device according to item 3D, wherein at least a portion of an outer edge of the inner wrapping body is exposed from the outer wrapping body.
Item 7D. Further comprising a metal terminal electrically connected to the electricity storage device element,
the inner wrapping body and the outer wrapping body are joined to the metal terminal,
Item 3D. The electricity storage device according to item 3D, wherein the inner packaging body is entirely covered by the outer packaging body.
Item 8D: The electricity storage device according to any one of Items 3D to 7D, wherein the packaging film for the electricity storage device further has transparency.

As described above, the fifth aspect of the present disclosure provides the invention having the following aspects.
Item 1E. A power storage device element;
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed;
a functional object disposed between the inner wrapper and the outer wrapper,
The functional object is an electricity storage device having shock absorbing properties.
Item 2E. A power storage device element;
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed;
a functional object disposed between the inner wrapper and the outer wrapper,
The functional object is a flame-retardant electricity storage device.
Item 3E. A power storage device element;
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed;
a functional object disposed between the inner wrapper and the outer wrapper,
The functional object is an electricity storage device having a cooling property.
Item 4E. A power storage device element,
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed;
a functional object disposed between the inner wrapper and the outer wrapper,
The functional object is an electricity storage device having a fire extinguishing property.
Item 5E. A power storage device element,
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed therein;
At least one of the inner wrapping body and the outer wrapping body has at least one of shock absorbing properties, flame retardancy, cooling properties, and fire extinguishing properties.
Item 6E: The electricity storage device according to any one of Items 1E to 5E, wherein the inner packaging body has at least one of transparency and gas permeability.
Item 7E. A metal terminal electrically connected to the electricity storage device element;
a tab film disposed between the inner wrapper and the metal terminal,
The outer wrapper is joined to the inner wrapper,
the inner wrapping body and the metal terminal are joined via the tab film,
Item 6E. The electricity storage device according to any one of Items 1E to 6E, wherein at least a portion of an outer edge of the inner wrapping body is exposed from the outer wrapping body.
Item 8E. A metal terminal electrically connected to the electricity storage device element;
a tab film disposed between the inner wrapping body and the metal terminal, and between the outer wrapping body and the metal terminal;
the inner wrapping body and the outer wrapping body are joined to the metal terminal via the tab film,
The electricity storage device according to any one of Items 1E to 6E, wherein the inner packaging body is entirely covered by the outer packaging body.
Item 9E. The power storage device further includes a metal terminal electrically connected to the power storage device element,
The inner packaging body and the metal terminal are joined together,
Item 6E. The electricity storage device according to any one of Items 1E to 6E, wherein at least a portion of an outer edge of the inner wrapping body is exposed from the outer wrapping body.
Item 10E. Further comprising a metal terminal electrically connected to the electricity storage device element,
the inner wrapping body and the outer wrapping body are joined to the metal terminal,
The electricity storage device according to any one of Items 1E to 6E, wherein the inner packaging body is entirely covered by the outer packaging body.

1 Heat-sealable resin layer 2 Resin layer 3 Substrate 4 Adhesive layer 5 Adhesive layer 10 Packaging film for electricity storage device 10a Inner packaging body 20 Outer packaging body 30 Electricity storage device 30a Peripheral edge portion 31 Metal terminal 32 Electricity storage device element S Shielding layer 100 Electricity storage device 130 Metal terminal 140 Tab film 210 Inner packaging body 211 Packaging film for electricity storage device 212 Packaging film for electricity storage device 220 Outer packaging body 230 Functional object

Claims (5)

A method for manufacturing an electricity storage device, comprising:
The power storage device is
An electricity storage device element;
and an inner packaging body that houses the electricity storage device element,
the inner packaging body is composed of a gas-permeable packaging film for an electricity storage device,
an inner wrapping step of wrapping the electricity storage device element with the electricity storage device packaging film;
an inner sealing step, which is carried out after the inner wrapping step, of sealing the packaging film for the electricity storage device so that the electricity storage device element is hermetically sealed by the packaging film for the electricity storage device;
a degassing step, which is carried out after the inner sealing step, of releasing gas generated from the electricity storage device elements through the electricity storage device packaging film. The method for producing an electricity storage device according to claim 1 , wherein in the inner wrapping step, the electricity storage device element is wrapped in the electricity storage device packaging film having substantially the same size as the inner wrapping body of a completed electricity storage device. An electricity storage device element;
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed therein;
the inner packaging body is formed of a gas-permeable packaging film for an electricity storage device ,
a metal terminal electrically connected to the electricity storage device element;
a tab film disposed between the inner wrapper and the metal terminal,
The outer wrapper is joined to the inner wrapper,
the inner wrapping body and the metal terminal are joined via the tab film,
At least a portion of an outer edge of the inner wrapper is exposed from the outer wrapper . An electricity storage device element;
an inner packaging body that houses the electricity storage device element;
an outer packaging body that houses the inner packaging body in a state in which the power storage device element is housed therein;
the inner packaging body is formed of a gas-permeable packaging film for an electricity storage device,
a metal terminal electrically connected to the power storage device element;
The inner packaging body and the metal terminal are joined together,
At least a portion of an outer edge of the inner wrapper is exposed from the outer wrapper. The electricity storage device according to claim 3 , wherein the packaging film for the electricity storage device further has transparency.

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