JP7435471B2 - Exterior material for power storage device, manufacturing method thereof, and power storage device - Google Patents

Description

The present disclosure relates to an exterior material for a power storage device, a method for manufacturing the same, and a power storage device.

Conventionally, various types of power storage devices have been developed, and in all power storage devices, an exterior material has become an essential member for sealing power storage device elements such as electrodes and electrolytes. Conventionally, metal exterior materials have been frequently used as exterior materials for power storage devices.

On the other hand, in recent years, as electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like have become more sophisticated, power storage devices are required to have a variety of shapes, as well as to be thinner and lighter. However, metal exterior materials for power storage devices, which have been widely used in the past, have the disadvantage that it is difficult to keep up with the diversification of shapes, and there is also a limit to the reduction in weight.

Therefore, in recent years, film-like materials in which a base material layer, a barrier layer, and a heat-fusible resin layer are sequentially laminated have been developed as exterior materials for power storage devices that can be easily processed into various shapes and can be made thinner and lighter. A laminate has been proposed (see, for example, Patent Document 1).

In such exterior materials for power storage devices, generally, a recess is formed by cold forming, power storage device elements such as electrodes and electrolyte are arranged in the space formed by the recess, and heat-sealable resin is placed in the space formed by the recess. By heat-sealing the layers, a power storage device in which power storage device elements are housed inside the power storage device exterior material is obtained.

JP2008-287971A Japanese Patent Application Publication No. 2015-166261

For example, power storage devices such as lithium ion secondary batteries are sometimes required to be colored black in order to unify the appearance and color of electrical equipment and other equipment to which they are attached (for example, see Patent Document 2). reference).

On the other hand, in the manufacturing process of power storage devices using exterior materials for power storage devices, identification marks such as product information (for example, letters and numbers indicating lot numbers, bar codes, symbols, etc.) are placed on the surface of the power storage devices. may be printed. By attaching an identification mark to the surface of the electricity storage device, it is possible to distinguish between a genuine product and a counterfeit product, for example. Similarly, in the manufacturing process of an exterior material for a power storage device, an identification mark or the like may be printed on the outer surface.

However, the inventors of the present disclosure have investigated that when coloring an electricity storage device or an exterior material for an electricity storage device so that its appearance appears black, the identifiability of printed identification marks etc. decreases in the manufacturing process of these devices. A new challenge was discovered.

Specifically, in the manufacturing process of power storage devices and exterior materials for power storage devices, processing and inspection may be performed under a yellow light source, such as in a yellow room. However, if identification marks are printed on power storage devices or exterior materials for power storage devices that have a black exterior and are processed or inspected under a light source in a yellow room, the identifiability of the identification marks decreases and product information, etc. A problem was discovered in which there was a risk that accurate reading could not be performed.

Under these circumstances, the present disclosure provides a power storage device in which an identification mark printed on the surface is highly distinguishable under a light source in a yellow room, even though the exterior material for the power storage device has a black appearance. The main purpose is to provide exterior materials for automobiles.

The inventors of the present disclosure have conducted extensive studies to solve the above problems. As a result, measurements were taken from the outside under predetermined conditions for an exterior material for a power storage device that is composed of a laminate including at least a base layer, a barrier layer, and a heat-fusible resin layer in order from the outside and has a black appearance. By setting the b ^* value in the L ^* a ^* b ^* color space of the reflected light to a predetermined value or less, it is possible to adjust the black to a black that exhibits a bluish hue, which is a complementary color to yellow. It has been found that the identifiability of identification marks printed on the surface can be improved in a yellow room or under an orange to yellow lamp light source.

The present disclosure has been completed through further studies based on these findings. That is, the present disclosure provides inventions of the following aspects.
An exterior material for a power storage device having a black appearance,
The exterior material for a power storage device is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-fusible resin layer,
A battery whose b ^* value in the L ^* a ^* b ^* color space of reflected light measured from the outside of the laminate under the measurement conditions of SCI method, field of view of 10°, and light source F2 is −0.20 or less. Exterior material for devices.

According to the present disclosure, although the exterior material for a power storage device has a black appearance, identification marks printed on the surface can be identified in a yellow room or under a light source of an orange to yellow lamp (Na lamp). It is possible to provide an exterior material for a power storage device with excellent properties. Further, according to the present disclosure, it is also possible to provide a method for manufacturing the exterior material for a power storage device, and an energy storage device using the exterior material for a power storage device.

It is a schematic diagram showing an example of the cross-sectional structure of the exterior material for electricity storage devices of this indication. It is a schematic diagram showing an example of the cross-sectional structure of the exterior material for electricity storage devices of this indication. It is a schematic diagram showing an example of the cross-sectional structure of the exterior material for electricity storage devices of this indication. It is a schematic diagram showing an example of the cross-sectional structure of the exterior material for electricity storage devices of this indication. It is a schematic diagram showing an example of the cross-sectional structure of the exterior material for electricity storage devices of this indication. It is a schematic diagram showing an example of the cross-sectional structure of the exterior material for electricity storage devices of this indication.

The exterior material for an energy storage device of the present disclosure is an exterior material for an energy storage device that has a black appearance, and the exterior material for an energy storage device includes, in order from the outside, at least a base layer, a barrier layer, and a heat-fusible resin. The b ^* value in the L ^* a ^* b ^* color space of reflected light measured from the outside under the measurement conditions of SCI method, field of view 10°, and light source F2 is -0. It is characterized by being .20 or less. According to the exterior material for a power storage device of the present disclosure, by having the configuration, even though the exterior material for a power storage device has a black appearance, it does not print on the surface under a light source in a yellow room. It is possible to demonstrate the excellent identifiability of the identification mark.

Hereinafter, the exterior material for a power storage device of the present disclosure will be described in detail. In this specification, the numerical range indicated by "~" means "more than" or "less than". For example, the expression 2 to 15 mm means 2 mm or more and 15 mm or less.

In addition, in the exterior material for a power storage device of the present disclosure, "having a black appearance" means that when the exterior material for a power storage device is observed from the outside with the naked eye, it is recognized as black. . More specifically, "black" in "appearance is black" has an L ^* value of 40 or less, preferably 35 or less in CIE1976 L ^* a ^* b ^* (CIELAB) chromaticity coordinates. Note that the L ^* value is also in the L ^* a ^* b ^* color space of reflected light, measured from the outside under the measurement conditions of the SCI method, field of view of 10°, and light source F2. Furthermore, in addition to the L ^* value, black preferably has an a ^* value of −20 to +20, more preferably −10 to +10. The exterior material for a power storage device of the present disclosure is characterized by a black appearance and a b ^* value of -0.20 or less.

As described below, the additives and coloring contained in each layer (layers located outside the barrier layer such as the base layer, adhesive layer, colored layer, and surface coating layer) constituting the exterior material for the power storage device of the present disclosure By adjusting the composition such as the type and content of the agent, the composition of the layer located outside the barrier layer, and the aging treatment conditions for the exterior material for energy storage devices, which will be described later, the appearance of the exterior material for energy storage devices can be changed. is set to black, and the b ^* value etc. can be adjusted. It is preferable to adjust the b ^* value using at least a black additive or coloring agent (for example, a black pigment), but the b ^* value can be adjusted by mixing multiple types of non-black additives or coloring agents to produce black color. You may. Further, among the layers constituting the exterior material for a power storage device of the present disclosure, one layer contains a black additive or colorant, and the other layers contain a non-black (for example, blue) additive or colorant. The b ^* value may be adjusted by multiple layers.

In addition, the term "inside a yellow room" refers to a room in which light with a wavelength of 500 nm or less, including ultraviolet rays, is blocked, and the light in the room is visually recognized as yellow. A yellow room is generally provided in a clean room of a semiconductor factory, for example, to perform a photolithography process in which a photosensitive material is handled.

1. Laminated structure and physical properties of exterior material for power storage devices The exterior material 10 for power storage devices of the present disclosure includes, for example, as shown in FIG. It is composed of a laminate comprising: In the exterior material 10 for a power storage device, the base layer 1 is the outermost layer, and the heat-fusible resin layer 4 is the innermost layer. When assembling a power storage device using the power storage device exterior material 10 and the power storage device element, heat-seal the peripheral edges with the heat-sealable resin layers 4 of the power storage device exterior material 10 facing each other. A power storage device element is accommodated in the space formed by. In the laminate forming the exterior material 10 for a power storage device according to the present disclosure, with the barrier layer 3 as a reference, the heat-fusible resin layer 4 side is on the inner side than the barrier layer 3, and the base material layer 1 side is on the inner side than the barrier layer 3. It is outside.

For example, as shown in FIGS. 2 and 4 to 6, the exterior material 10 for a power storage device has a structure that increases the adhesion between the base layer 1 and the barrier layer 3 (as described below). If necessary, the adhesive layer 2 may be provided for purposes such as coloring the exterior material 10 for the power storage device. Further, as shown in FIGS. 3 and 4, for example, a colored layer 21 may be provided between the base material layer 1 and the barrier layer 3 for the purpose of coloring the exterior material 10 for the electricity storage device. You may do so. In addition, as shown in FIGS. 5 and 6, for example, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-fusible resin layer 4 for the purpose of increasing the adhesion between these layers. It may have. Further, as shown in FIG. 6, a surface coating layer 6 or the like may be provided on the outside of the base material layer 1 (on the side opposite to the heat-fusible resin layer 4 side), if necessary.

The thickness of the laminate constituting the exterior material 10 for power storage devices is not particularly limited, but from the viewpoint of cost reduction, improvement of energy density, etc., it is preferably about 180 μm or less, about 155 μm or less, or about 120 μm or less. In addition, from the viewpoint of maintaining the function of the exterior material for an energy storage device to protect the energy storage device elements, the thickness of the laminate constituting the exterior material 10 for an energy storage device is preferably about 35 μm or more, about 45 μm or more, or about 45 μm or more. Examples include 60 μm or more. Further, preferred ranges of the thickness of the laminate that constitutes the exterior material 10 for power storage devices include, for example, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 180 μm, about 45 to 155 μm, and about 45 to 155 μm. Examples include about 120 μm, about 60 to 180 μm, about 60 to 155 μm, and about 60 to 120 μm.

The exterior material 10 for a power storage device of the present disclosure has a b ^* value in the L ^* a ^* b ^* color space of reflected light measured from the outside under the measurement conditions of the SCI method, a field of view of 10°, and a light source F2. .20 or less. By setting the upper limit of the b ^* value to such a specific value, it is possible to adjust the exterior material for power storage devices that has a black appearance to black that has a bluish hue, which is a complementary color to yellow. The identification mark printed on the surface exhibits excellent identifiability in a yellow room or under a yellow light source.

The b ^* value is not particularly limited as long as it is -0.20 or less, but from the viewpoint of further improving the identifiability and suitably recognizing that the appearance is black, it is preferably about -0.50 or less, more preferably about -0.80 or less. Further, from the same viewpoint, the b ^* value is preferably about -5.00 or more, more preferably about -4.00 or more, still more preferably about -2.00 or more, and even more preferably about -1.50. The above can be mentioned. In addition, the preferable range of b ^* value is -5.00 to -0.20, -5.00 to -0.50, -5.00 to -0.80, -4.00 to - Around 0.20, around -4.00 to -0.50, around -4.00 to -0.80, around -2.00 to -0.20, around -2.00 to -0.50, - Examples include about 2.00 to -0.80, -1.50 to -0.20, -1.50 to -0.50, and -1.50 to -0.80. Among these, the b ^* value is particularly preferably about -1.50 to -0.80.

In addition, the exterior material 10 for a power storage device of the present disclosure has an a ^* value in the L ^* a ^* b ^* color space of reflected light measured from the outside under the measurement conditions of the SCI method, a field of view of 10°, and a light source F2. It is preferable that it is +0.20 or less. This further improves the identifiability and allows the user to conveniently recognize that the appearance is black.

The a ^* value is more preferably about +0.10 or less, still more preferably +0.04 or less, and even more preferably about +0.04 or less, from the viewpoint of further improving the distinguishability and suitably recognizing that the appearance is black. It is about +0.02 or less, more preferably about 0.00 or less, even more preferably about -0.01 or less. Further, from the same viewpoint, the a ^* value is preferably about -3.50 or more, more preferably about -3.00 or more, even more preferably about -2.00 or more, and even more preferably about -0.50. Above, more preferably about -0.30 or more, still more preferably about -0.15 or more, still more preferably about -0.10 or more. In addition, the preferable range of a ^* value is about -3.50 to +0.20, -3.50 to +0.10, -3.50 to +0.04, and -3.50 to +0.02. , -3.50 to about 0.00, -3.50 to -0.01, -3.00 to +0.20, -3.00 to +0.10, -3.00 to +0.04 degree, -3.00 to +0.02, -3.00 to +0.00, -3.00 to -0.01, -2.00 to +0.20, -2.00 to +0. About 10, -2.00 to +0.04, -2.00 to +0.02, -2.00 to 0.00, -2.00 to -0.01, -0.50 to +0 About .20, -0.50 to +0.10, -0.50 to +0.04, -0.50 to +0.02, -0.50 to 0.00, -0.50 to - About 0.01, -0.30 to +0.20, -0.30 to +0.10, -0.30 to +0.04, -0.30 to +0.02, -0.30 to Around 0.00, around -0.30 to -0.01, around -0.15 to +0.20, around -0.15 to +0.10, around -0.15 to +0.04, -0.15 ~+0.02, -0.15 to 0.00, -0.15 to -0.01, -0.10 to +0.20, -0.10 to +0.10, -0. Examples include about 10 to +0.04, -0.10 to +0.02, -0.10 to 0.00, and -0.10 to -0.01. Among these, the a ^* value is particularly preferably about -0.30 to -0.01, and about -0.10 to -0.01.

In addition, the exterior material 10 for a power storage device of the present disclosure has an L ^* value in the L ^* a ^* b ^* color space of reflected light measured from the outside under the measurement conditions of the SCI method, the field of view of 10°, and the light source F2. It is preferably 35.0 or less. This further improves the identifiability and allows the user to conveniently recognize that the appearance is black.

The L ^* value is more preferably about 33.0 or less, more preferably about 30.0 or less, and even more preferably about 30.0 or less, from the viewpoint of further improving the identifiability and suitably recognizing that the appearance is black. is about 28.0 or less. Further, from the same viewpoint, the L ^* value is preferably about 25.0 or more, more preferably about 26.0 or more. In addition, the preferable range of the L ^* value is about 25.0 to 35.0, about 25.0 to 33.0, about 25.0 to 30.0, about 25.0 to 28.0, and about 26.0. - about 35.0, about 26.0 to 33.0, about 26.0 to 30.0, and about 26.0 to 28.0. Among these, the L ^* value is particularly about 25.0 to 30.0, 26.0 to 30.0, further 26.0 to 29.0, and even 26.0 to 28.0. is preferred.

<Measurement of L ^* value, a ^* value and b ^* value>
In the present disclosure, the L ^* value, a ^* value, and b ^* value are values measured by the following method. Regarding the exterior material for power storage devices, the observation conditions of a spectrophotometer (for example, CM-700d, manufactured by Konica Minolta) calibrated with a white calibration cap (for example, CM-A177, manufactured by Konica Minolta) were set to 10°, and the observation light source was set to F2. , Set to SCI mode (JIS Z8722-2009), and measure L ^* , a ^* , and b ^* on the outer (base layer side) surface at room temperature and humidity. Measurements are made at three points for each sample, and the average value is taken as the measured value. Furthermore, it is also possible to obtain the exterior material for a power storage device from the power storage device and measure the L ^* value, a ^* value, and b ^* value from the outside of the laminate that constitutes the exterior material for the power storage device. When acquiring and measuring the power storage device exterior material from the power storage device, the measurement target is the top surface portion where the power storage device exterior material is not stretched by molding.

In the exterior material for a power storage device of the present disclosure and a power storage device using the same, examples of the printed identification mark include letters and numbers indicating a lot number, a bar code, a symbol, and the like. In addition, the color of the ink used to print the identification mark (that is, the color of the identification mark) is preferably white because it provides excellent identification in the exterior material for an electricity storage device of the present disclosure that has a black appearance.

2. Each layer forming the exterior material for power storage device [base material layer 1]
In the present disclosure, the base material layer 1 is a layer provided for the purpose of exhibiting a function as a base material of an exterior material for a power storage device. Base material layer 1 is located on the outer layer side of the exterior material for a power storage device.

The material forming the base material layer 1 is not particularly limited as long as it has a function as a base material, that is, it has at least insulation properties. The base material layer 1 can be formed using, for example, a resin, and the resin may contain additives described below. For example, the above L ^* value, a ^* value, and b ^* value can be adjusted by blending additives and colorants described below in the base material layer.

When the base material layer 1 is formed of resin, the base material layer 1 may be, for example, a resin film formed of resin, or may be formed by applying resin. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include uniaxially stretched film and biaxially stretched film, with biaxially stretched film being preferred. Examples of the stretching method for forming a biaxially stretched film include a sequential biaxial stretching method, an inflation method, and a simultaneous biaxial stretching method. Examples of methods for applying the resin include roll coating, gravure coating, and extrusion coating.

Examples of the resin forming the base layer 1 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, and modified products of these resins. Further, the resin forming the base material layer 1 may be a copolymer of these resins or a modified product of the copolymer. Furthermore, a mixture of these resins may be used.

Among these, preferred examples of the resin forming the base layer 1 include polyester and polyamide.

Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymerized polyester, and the like. Examples of the copolyester include copolyesters containing ethylene terephthalate as a main repeating unit. Specifically, copolymer polyester polymerized with ethylene isophthalate with ethylene terephthalate as the main repeating unit (hereinafter abbreviated as polyethylene (terephthalate/isophthalate)), polyethylene (terephthalate/adipate), polyethylene (terephthalate/adipate), etc. Examples include sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate), and polyethylene (terephthalate/decanedicarboxylate). 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; terephthalic acid and/or isophthalic acid; Hexamethylenediamine-isophthalic acid-terephthalic acid copolyamides, polyamide MXD6 (polymethacrylic acid), etc. containing structural units derived from nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid), etc. Aromatic polyamides such as polyamide (silylene adipamide); alicyclic polyamides such as polyamide PACM6 (polybis(4-aminocyclohexyl)methaneadipamide); and lactam components and isocyanate components such as 4,4'-diphenylmethane-diisocyanate. Polyamides such as copolymerized polyamides, polyesteramide copolymers and polyetheresteramide copolymers which are copolymers of copolymerized polyamides and polyesters or polyalkylene ether glycols; and copolymers of these are exemplified. These polyamides may be used alone or in combination of two or more.

The base layer 1 preferably contains at least one of a polyester film, a polyamide film, and a polyolefin film, and preferably contains at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, More preferably, at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film is included, and the film preferably includes a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, and a biaxially stretched nylon film. , a biaxially oriented polypropylene film.

The base material layer 1 may be a single layer or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or a resin film may be coextruded to form two or more layers. It may also be a laminate of resin films. Further, a laminate of two or more resin films formed by coextruding resins may be used as the base layer 1 without being stretched, or may be uniaxially or biaxially stretched as the base layer 1.

In the base material layer 1, 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 layers of stretched nylon films, and a laminate of two or more layers of stretched polyester films are preferred. For example, when the base material layer 1 is a laminate of two resin films, it may be 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. A laminate 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, since polyester resin is difficult to discolor when an electrolyte adheres to its surface, for example, when the base layer 1 is a laminate of two or more resin films, the polyester resin film is the same as the base layer 1. Preferably, it is located in the outermost layer.

When the base material layer 1 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. Preferred adhesives include those similar to the adhesives exemplified in adhesive layer 2 described below. The method for laminating two or more layers of resin films is not particularly limited, and any known method can be used, such as a dry lamination method, a sandwich lamination method, an extrusion lamination method, a thermal lamination method, etc., and preferably a dry lamination method. One example is the lamination method. When laminating by dry lamination, it is preferable to use a polyurethane adhesive as the adhesive. At this time, the thickness of the adhesive is, for example, about 2 to 5 μm. Alternatively, an anchor coat layer may be formed on a resin film and laminated thereon. Examples of the anchor coat layer include the same adhesive as the adhesive layer 2 described below. At this time, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

Further, even if additives such as lubricants, flame retardants, anti-blocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents are present on at least one of the surface and inside of the base layer 1, good. Only one type of additive may be used, or a mixture of two or more types may be used.

In the present disclosure, it is preferable that a lubricant be present on the surface of the base material layer 1 from the viewpoint of improving the moldability of the exterior material for a power storage device. The lubricant is not particularly limited, but preferably includes an amide lubricant. Specific examples of amide lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, aromatic bisamides, and the like. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, and the like. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, and the like. Furthermore, specific examples of methylolamide include methylolstearamide and the like. Specific examples of saturated fatty acid bisamides include methylene bisstearamide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, and hexamethylene bis stearic acid amide. Examples include acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, and the like. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyladipic acid amide, and N,N'-dioleyl sebacic acid amide. Examples include. Specific examples of fatty acid ester amides include stearamide ethyl stearate. Specific examples of aromatic bisamides include m-xylylene bisstearamide, m-xylylene bishydroxystearamide, and N,N'-distearylisophthalic acid amide. One type of lubricant may be used alone, or two or more types may be used in combination.

When a lubricant is present on the surface of the base layer 1, its amount is not particularly limited, but is preferably about 3 mg/m ² or more, more preferably about 4 to 15 mg/m ² , and even more preferably 5 to 14 mg. / ^m2 .

The lubricant present on the surface of the base layer 1 may be one obtained by exuding a lubricant contained in the resin constituting the base layer 1, or a lubricant coated on the surface of the base layer 1. It's okay.

The thickness of the base material layer 1 is not particularly limited as long as it functions as a base material, but may be, for example, about 3 to 50 μm, preferably about 10 to 35 μm. When the base layer 1 is a laminate of two or more layers of resin films, the thickness of the resin films constituting each layer is preferably about 2 to 25 μm.

For example, when the adhesive layer is a layer colored black, the base material layer located outside the adhesive layer is preferably transparent or translucent.

[Adhesive layer 2]
In the exterior material for a power storage device according to the present disclosure, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary for the purpose of increasing the adhesiveness between the two.

Moreover, in the exterior material for a power storage device of the present disclosure, the adhesive layer 2 may be colored black. By coloring the adhesive layer 2 black, an exterior material for a power storage device having a black appearance can be obtained, and the b ^* value can be suitably set to -0.20 or less. However, if the adhesive layer 2 is colored black, the b ^* value will not become -0.20 or less. The composition such as the type and content of the coloring agent contained in the adhesive layer 2, the base layer 1, and the layers located outside the barrier layer 3 such as the surface coating layer 6 and colored layer 21 provided as necessary. By adjusting the composition, furthermore, the aging treatment conditions of the exterior material for the electricity storage device, which will be described later, the appearance of the exterior material for the energy storage device is made black, and the b ^* value is set to -0.20 or less. Can be done. The same applies to the setting of the L ^* value and the a ^* value.

The adhesive layer 2 is formed of an adhesive capable of bonding the base material layer 1 and the barrier layer 3 together. The adhesive used to form the adhesive layer 2 is not limited, but may be any one of a chemical reaction type, a solvent volatilization type, a heat melt type, a heat pressure type, and the like. Further, 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. Furthermore, the adhesive layer 2 may be a single layer or a multilayer.

Specifically, the adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; polyether; polyurethane; epoxy resin; Phenol resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymerized polyamides; polyolefin resins such as polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; Examples include polyimide; polycarbonate; amino resins such as urea resin and melamine resin; 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. Further, the adhesive strength of these adhesive component resins can be increased by using an appropriate curing agent in combination. The curing agent is selected from among polyisocyanates, polyfunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, etc., depending on the functional groups of the adhesive component.

Examples of the polyurethane adhesive include a polyurethane adhesive containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred examples include two-component curing polyurethane adhesives that use polyols such as polyester polyols, polyether polyols, and acrylic polyols as a main ingredient and aromatic or aliphatic polyisocyanates as a curing agent. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in the side chain in addition to the hydroxyl group at the end of the repeating unit. Examples of the curing agent include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. 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), naphthalene diisocyanate (NDI), and the like. Also included are polyfunctional isocyanate modified products of one or more of these diisocyanates. It is also possible to use multimers (for example trimers) as the polyisocyanate compound. Such multimers include adducts, biurets, nurates, and the like. In addition, an aliphatic isocyanate-based compound refers to an isocyanate that has an aliphatic group and does not have an aromatic ring, and an alicyclic isocyanate-based compound refers to an isocyanate that has an alicyclic hydrocarbon group. refers to an isocyanate having an aromatic ring. Since the adhesive layer 2 is formed of a polyurethane adhesive, the exterior material for the power storage device has excellent electrolyte resistance, and peeling of the base material layer 1 is suppressed even if the electrolyte adheres to the side surface. .

Further, the adhesive layer 2 may contain other components such as colorants, thermoplastic elastomers, tackifiers, fillers, etc., as long as they do not impede adhesiveness. Since the adhesive layer 2 contains the coloring agent, the exterior material for the electricity storage device can be colored. As the colorant, known colorants such as pigments and dyes can be used. Moreover, only one type of coloring agent may be used, or two or more types of coloring agents may be used in combination.

The type of pigment is not particularly limited as long as the above-mentioned b ^* value is -0.20 or less and the adhesiveness of the adhesive layer 2 is not impaired. Examples of organic pigments include azo pigments, phthalocyanine pigments, quinacridone pigments, anthraquinone pigments, dioxazine pigments, indigothioindigo pigments, perinone-perylene pigments, isoindolenine pigments, and benzimidazolone pigments. Examples of pigments include carbon black-based, titanium-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, as well as mica (mica) fine powder, fish scale foil, etc. It will be done.

The average particle diameter of the pigment is not particularly limited as long as the above-mentioned b ^* value is -0.20 or less and the adhesiveness of the adhesive layer 2 is not impaired, for example, about 0.05 to 5 μm, preferably Examples include about 0.08 to 2 μm. Note that the average particle diameter of the pigment is the median diameter measured by a laser diffraction/scattering particle diameter distribution measuring device. Note that when the primary particle diameter of the pigment changes, the L ^* value, a ^* value, and b ^* value described above change even if the pigment is of the same type. For example, when the primary particle size of the black pigment becomes large, the black color may become slightly bluish. Therefore, in the present disclosure, it is also preferable to adjust the primary particle diameter of the pigment used in setting the L ^* value, a ^* value, and b ^* value. The secondary particle diameter of the pigment is preferably about 0.8 μm or less, more preferably about 0.6 μm or less, and still more preferably about 0.4 μm or less. Further, the secondary particle diameter of the pigment is preferably about 0.05 μm or more, more preferably about 0.1 μm or more. The preferable range of the secondary particle diameter of the pigment is about 0.05 to 0.8 μm, about 0.05 to 0.6 μm, about 0.05 to 0.4 μm, about 0.1 to 0.8 μm, and about 0.05 to 0.8 μm. Examples include about 1 to 0.6 μm and about 0.1 to 0.4 μm.

Among the coloring agents, it is preferable to use a black agent in order to make the outer packaging material for an electricity storage device appear black. A black agent is an additive such as a pigment or dye that can be colored black, and is a black coloring agent. Examples of the black agent include black pigments. As the black pigment, carbon and titanium pigments are preferred. Note that a black pigment made of carbon is generally called carbon black. Titanium black is preferred as the titanium pigment. Further, a mixture of carbon black and titanium black may be used.

Furthermore, from the viewpoint of making the external appearance of the exterior material for the power storage device black and suitably setting the b ^* value to -0.20 or less to improve the identifiability, the adhesive layer 2 is made of a black adhesive. In addition to this, it is preferable to further include a blue coloring agent. A blue agent is an additive such as a pigment or dye that can be colored blue, and is a blue coloring agent. Examples of the blue agent include dyes such as anthraquinone and indigoid, and pigments such as phthalocyanine, ultramarine, ferric ferrocyanide, and navy blue. Examples of the phthalocyanine include copper phthalocyanine and metal-free phthalocyanine, with copper phthalocyanine being preferred. It is. Copper phthalocyanine is known as a blue pigment.

It is preferable that Cu element be detected when an analysis by X-ray fluorescence spectrometry (XRF) is performed from the outside of the laminate that constitutes the exterior material for a power storage device according to the present disclosure. For example, if the adhesive layer 2 of the exterior material for a power storage device contains a pigment containing copper (e.g., copper phthalocyanine), if analysis is performed from the outside of the laminate using X-ray fluorescence spectrometry (XRF), Cu element is detected. As will be described later, even when the surface coating layer 6 and the colored layer 21 contain pigments containing copper (e.g. copper phthalocyanine), when analyzed from the outside by X-ray fluorescence spectrometry (XRF), Cu elements are detected. Detected. For detection of Cu element by X-ray fluorescence analysis (XRF), the measurement conditions described in Examples can be adopted.

The content of the coloring agent in the adhesive layer 2 is not particularly limited as long as the exterior material for the electricity storage device is colored black and the b ^* value is −0.20 or less; from the viewpoint of appropriate coloring, Preferably it is about 0.5% by weight or more, more preferably about 1.0% by weight or more. In addition, from the viewpoint of appropriately maintaining the adhesiveness between the base material layer 1 and the barrier layer 3, the content of the colorant in the adhesive layer 2 is preferably about 50.0% by mass or less, more preferably about 30% by mass or less. It is .0 mass % or less, more preferably 20.0 mass % or less. The preferable range of the content of the colorant in the adhesive layer 2 is about 0.5 to 50.0% by mass, about 0.5 to 30.0% by mass, about 0.5 to 20.0% by mass, 1 Examples include about .0 to 50.0% by mass, about 1.0 to 30.0% by mass, and about 1.0 to 20.0% by mass.

Further, when a black agent is added as a coloring agent to the adhesive layer 2, the content of the black agent in the adhesive layer 2 is such that the exterior material for the electricity storage device is colored black and the b ^* value is -0. There is no particular restriction as long as it is 20 or less, but from the viewpoint of appropriate coloring, it is preferably about 0.5% by mass or more, more preferably about 1.0% by mass or more. Further, from the viewpoint of appropriately maintaining the adhesiveness between the base layer 1 and the barrier layer 3, the content of the black agent in the adhesive layer 2 is preferably about 50.0% by mass or less, more preferably about 30% by mass or less. It is .0 mass % or less, more preferably 20.0 mass % or less. Further, the preferable range of the content of the black agent in the adhesive layer 2 is about 0.5 to 50.0% by mass, about 0.5 to 30.0% by mass, and about 0.5 to 20.0% by mass. , about 1.0 to 50.0% by mass, about 1.0 to 30.0% by mass, and about 1.0 to 20.0% by mass. Further, when a blue agent is added to the adhesive layer 2, the content of the blue agent in the adhesive layer 2 is not particularly limited as long as the exterior material for the electricity storage device is colored black; for example, 0.5 to 30 About 1% by mass, preferably 1 to 20% by mass.

Further, when blending a black agent and a blue agent in the adhesive layer 2, the ratio of the black agent and the blue agent in the adhesive layer 2 is preferably about 0. .1 part by weight or more, more preferably about 1 part by weight or more, even more preferably about 10 parts by weight or more. Further, the proportion of the blue agent is preferably about 150 parts by mass or less, more preferably about 100 parts by mass or less. The preferable range of the proportion of the blue agent is about 0.1 to 150 parts by weight, about 0.1 to 100 parts by weight, about 1 to 150 parts by weight, about 1 to 100 parts by weight, about 10 to 150 parts by weight, The amount is about 10 to 100 parts by mass. As mentioned above, it is possible to adjust the primary particle size of the pigment used, the composition of the layer located outside the barrier layer 3, and the aging treatment conditions of the exterior material for the electricity storage device, which will be described later. Since the L ^* value, a ^* value, and b ^* value can be set according to the above, the adhesive layer 2 may contain only a black agent as a coloring agent, and may not contain, for example, a blue agent.

The thickness of the adhesive layer 2 is not particularly limited as long as the base layer 1 and the barrier layer 3 can be bonded together, but is, for example, about 1 μm or more and about 2 μm or more. Further, the thickness of the adhesive layer 2 is, for example, about 10 μm or less, about 5 μm or less. Preferred ranges for the thickness of the adhesive layer 2 include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[Colored layer 21]
The colored layer 21 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary. When the adhesive layer 2 is provided, a colored layer 21 may be provided between the base material layer 1 and the adhesive layer 2 or between the adhesive layer 2 and the barrier layer 3 at least on one side. Further, a colored layer 21 may be provided on the outside of the base layer 1. By providing the colored layer 21, the exterior material for an electricity storage device can be suitably colored black.

In addition, in the exterior material for an electricity storage device of the present disclosure, the colored layer 21 is colored black to provide an exterior material for an electricity storage device that has a black appearance, and the b ^* value is set to -0.20 or less. It can be set appropriately. However, as in the case where the adhesive layer 2 is colored black, the b ^* value does not become -0.20 or less if the colored layer 21 is colored black. The composition such as the type and content of the coloring agent contained in the colored layer 21, the base material layer 1, and the layers located outside the barrier layer 3 such as the surface coating layer 6 and adhesive layer 2 provided as necessary. By adjusting the composition, furthermore, the aging treatment conditions of the exterior material for the electricity storage device, which will be described later, the appearance of the exterior material for the energy storage device is made black, and the b ^* value is set to -0.20 or less. Can be done. The same applies to the setting of the L ^* value and the a ^* value.

The colored layer 21 can be formed, for example, by applying ink containing a coloring agent to the surface of the base layer 1 or the surface of the barrier layer 3. As the colorant, known colorants such as pigments and dyes can be used. Moreover, only one type of coloring agent may be used, or two or more types of coloring agents may be used in combination.

As specific examples of the coloring agent contained in the colored layer 21, the same ones as those exemplified in the column of [Adhesive layer 2] are exemplified.

The content of the coloring agent in the colored layer 21 is not particularly limited as long as the exterior material for the electricity storage device is colored black and the b ^* value is -0.20 or less, and from the viewpoint of appropriate coloring, it is preferably It is about 0.5% by weight or more, more preferably about 1.0% by weight or more. Further, from the viewpoint of forming the colored layer 21 appropriately, the content of the coloring agent in the colored layer 21 is preferably about 50.0% by mass or less, more preferably about 30.0% by mass or less, and even more preferably 20.0% by mass or less. It is 0% by mass or less. The preferable range of the content of the colorant in the colored layer 21 is about 0.5 to 50.0% by mass, about 0.5 to 30.0% by mass, about 0.5 to 20.0% by mass, 1. Examples include about 0 to 50.0% by mass, about 1.0 to 30.0% by mass, and about 1.0 to 20.0% by mass.

In addition, when a black agent is added to the colored layer 21, the content of the black agent in the colored layer 21 is particularly high if the exterior material for the electricity storage device is colored black and the b ^* value is -0.20 or less. Although not limited, from the viewpoint of appropriate coloring, the content is preferably about 0.5% by mass or more, more preferably about 1.0% by mass or more. Further, from the viewpoint of forming the colored layer 21 appropriately, the content of the black agent in the colored layer 21 is preferably about 50.0% by mass or less, more preferably about 30.0% by mass or less, and even more preferably 20.0% by mass or less. It is 0% by mass or less. The preferred range of the content of the black agent in the colored layer 21 is approximately 0.5 to 50.0% by mass, approximately 0.5 to 30.0% by mass, approximately 0.5 to 20.0% by mass, 1. Examples include about 0 to 50.0% by mass, about 1.0 to 30.0% by mass, and about 1.0 to 20.0% by mass. Further, when a blue agent is added to the colored layer 21, the content of the blue agent in the colored layer 21 is not particularly limited as long as the exterior material for the electricity storage device is colored black, and is, for example, 0.5 to 30% by mass. degree, preferably 1 to 20% by mass.

In addition, when a black agent and a blue agent are blended in the colored layer 21, the ratio of the black agent and the blue agent in the colored layer 21 is preferably about 0.1 parts by mass when the black agent is 100 parts by mass. The amount is at least about 1 part by weight, more preferably about 1 part by weight or more, and even more preferably about 10 parts by weight or more. Further, the proportion of the blue agent is preferably about 150 parts by mass or less, more preferably about 100 parts by mass or less. The preferable range of the blue agent is about 0.1 to 150 parts by weight, about 0.1 to 100 parts by weight, about 1 to 150 parts by weight, about 1 to 100 parts by weight, about 10 to 150 parts by weight, 10 to 100 parts by weight. It is about parts by mass.

[Barrier layer 3]
In the exterior material for a power storage device, the barrier layer 3 is a layer that prevents at least moisture from entering.

Examples of the barrier layer 3 include a metal foil, a vapor deposited film, and a resin layer having barrier properties. Examples of the vapor-deposited film include a metal vapor-deposited film, an inorganic oxide vapor-deposited film, a carbon-containing inorganic oxide vapor-deposited film, etc., and resin layers include polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), and tetrafluoroethylene. Examples include fluorine-containing resins such as polymers containing fluoroethylene (TFE) as a main component, polymers having a fluoroalkyl group, and polymers containing fluoroalkyl units as a main component, and ethylene vinyl alcohol copolymers. Further, examples of the barrier layer 3 include a resin film provided with at least one of these vapor-deposited films and a resin layer. A plurality of barrier layers 3 may be provided. It is preferable that the barrier layer 3 includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include aluminum alloy, stainless steel, titanium steel, steel plate, etc. When used as metal foil, it includes at least one of aluminum alloy foil and stainless steel foil. It is preferable.

From the perspective of improving the formability of the exterior material for power storage devices, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, annealed aluminum alloy, and from the perspective of further improving the formability. Therefore, an aluminum alloy foil containing iron is preferable. In the aluminum alloy foil containing iron (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, it is possible to obtain an exterior material for a power storage device that has better formability. By having an iron content of 9.0% by mass or less, it is possible to obtain an exterior material for a power storage device that has more excellent flexibility. Examples of the soft aluminum alloy foil include an aluminum alloy having a composition specified by JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. One example is foil. Further, silicon, magnesium, copper, manganese, etc. may be added as necessary. Further, softening can be performed by annealing treatment or the like.

Examples of the stainless steel foil include austenitic, ferritic, austenite-ferritic, martensitic, and precipitation hardening stainless steel foils. Furthermore, from the viewpoint of providing an exterior material for a power storage device with excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, SUS316L, etc. Among these, SUS304 is particularly preferred.

In the case of metal foil, the thickness of the barrier layer 3 may be about 9 to 200 μm, as long as it can at least function as a barrier layer to prevent moisture from entering. The thickness of the barrier layer 3 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, particularly preferably about 35 μm or less. Further, the thickness of the barrier layer 3 is preferably about 10 μm or more, more preferably about 20 μm or more, and even more preferably about 25 μm or more. The preferred range of the thickness is about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, and about 25 to 35 μm. Examples include about 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 3 is made of aluminum alloy foil, the above range is particularly preferable. Further, in particular, when the barrier layer 3 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, and still more preferably about 30 μm or less, particularly preferably about 25 μm or less. Further, the thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Further, the preferred thickness range of the stainless steel foil is about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, Examples include about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

Moreover, when the barrier layer 3 is a metal foil, it is preferable that at least the surface opposite to the base material layer is provided with a corrosion-resistant film in order to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant film refers to, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment such as applying a coating agent to the surface of the barrier layer. A thin film that provides corrosion resistance to the barrier layer. As the treatment for forming a corrosion-resistant film, one type of treatment may be performed or a combination of two or more types may be performed. Furthermore, it is possible to have not only one layer but also multiple layers. Furthermore, among these treatments, hydrothermal conversion treatment and anodization treatment are treatments in which the surface of the metal foil is dissolved with a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may be included in the definition of chemical conversion treatment. Further, when the barrier layer 3 includes a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

Corrosion-resistant coatings are used to prevent delamination between the barrier layer (for example, aluminum alloy foil) and the base material layer during the molding of exterior materials for power storage devices, and to prevent delamination by hydrogen fluoride generated by the reaction between electrolyte and moisture. , prevents the dissolution and corrosion of the barrier layer surface, especially when the barrier layer is an aluminum alloy foil, and prevents the aluminum oxide present on the barrier layer surface from dissolving and corroding, and the adhesion (wettability) of the barrier layer surface. It shows the effect of preventing delamination between the base material layer and the barrier layer during heat sealing and the delamination between the base material layer and the barrier layer during molding.

Various types of corrosion-resistant coatings are known that are formed by chemical conversion treatment, and mainly include at least one of phosphates, chromates, fluorides, triazinethiol compounds, and rare earth oxides. Examples include corrosion-resistant coatings containing. Examples of chemical conversion treatments using phosphates and chromates include chromic acid chromate treatment, phosphoric acid chromate treatment, phosphoric acid-chromate treatment, and chromate treatment. Examples of the compound include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium diphosphate, chromic acid acetylacetate, chromium chloride, potassium chromium sulfate, and the like. Further, examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid. Examples of the chromate treatment include etching chromate treatment, electrolytic chromate treatment, coating type chromate treatment, and coating type chromate treatment is preferred. In this coating-type chromate treatment, at least the inner layer side of the barrier layer (for example, aluminum alloy foil) is first coated using a well-known method such as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activation method, etc. Degrease treatment is performed using a treatment method, and then metal phosphates such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, and Zn (zinc) phosphate are applied to the degreased surface. Treatment liquids whose main components are salts and mixtures of these metal salts, treatment liquids whose main components are nonmetallic phosphoric acid salts and mixtures of these nonmetallic salts, or combinations of these with synthetic resins, etc. This is a process in which a treatment liquid consisting of a mixture is applied by a well-known coating method such as a roll coating method, a gravure printing method, or a dipping method, and then dried. Various solvents such as water, alcohol solvents, hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents can be used as the treatment liquid, and water is preferable. In addition, the resin component used at this time includes polymers such as phenolic resins and acrylic resins, and aminated phenol polymers having repeating units represented by the following general formulas (1) to (4) are used. Examples include chromate treatment. In addition, in the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. Good too. The acrylic resin must be polyacrylic acid, acrylic acid methacrylate copolymer, acrylic acid maleic acid copolymer, acrylic acid styrene copolymer, or derivatives thereof such as sodium salt, ammonium salt, or amine salt. is preferred. Particularly preferred are polyacrylic acid derivatives such as ammonium salts, sodium salts, or amine salts of polyacrylic acid. In the present disclosure, polyacrylic acid refers to a polymer of acrylic acid. Further, the acrylic resin is also preferably a copolymer of acrylic acid and dicarboxylic acid or dicarboxylic anhydride, such as ammonium salt, sodium salt, Or it is also preferable that it is an amine salt. Only one type of acrylic resin may be used, or a mixture of two or more types may be used.

In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. Further, R ¹ and R ² are each the same or different and represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. In general formulas (1) to ( ^{4 )} , the alkyl group represented by Examples include straight chain or branched alkyl groups having 1 to 4 carbon atoms such as tert-butyl group. Furthermore, examples of the hydroxyalkyl group represented by X, R ¹ and R ² include hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, Straight chain or branched chain with 1 to 4 carbon atoms substituted with one hydroxy group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group Examples include alkyl groups. In the general formulas (1) to (4), the alkyl groups and hydroxyalkyl groups represented by X, R ¹ and R ² may be the same or different. In general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having repeating units represented by general formulas (1) to (4) is preferably about 500 to 1,000,000, and preferably about 1,000 to 20,000, for example. More preferred. Aminated phenol polymers can be produced, for example, by polycondensing a phenol compound or a naphthol compound with formaldehyde to produce a polymer consisting of repeating units represented by the above general formula (1) or general formula (3), and then adding formaldehyde to the polymer. and amine (R ¹ R ² NH) to introduce a functional group (-CH ₂ NR ¹ R ² ) into the polymer obtained above. Aminated phenol polymers may be used alone or in combination of two or more.

Another example of a corrosion-resistant film is a film formed by a coating-type corrosion-preventing treatment in which a coating agent containing at least one selected from the group consisting of a rare earth element oxide sol, an anionic polymer, and a cationic polymer is applied. Examples include thin films that are The coating agent may further contain phosphoric acid or a phosphate salt, a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol includes rare earth element oxide fine particles (for example, particles with an average particle size of 100 nm or less) dispersed in a liquid dispersion medium. Examples of rare earth element oxides include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide, with cerium oxide being preferred from the viewpoint of further improving adhesion. The rare earth element oxides contained in the corrosion-resistant film can be used alone or in combination of two or more. As the liquid dispersion medium for the rare earth element oxide sol, various solvents such as water, alcohol solvents, hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents can be used, with water being preferred. Examples of the cationic polymer include polyethyleneimine, an ionic polymer complex consisting of a polymer containing polyethyleneimine and a carboxylic acid, a primary amine-grafted acrylic resin in which a primary amine is graft-polymerized onto an acrylic main skeleton, polyallylamine or its derivatives. , aminated phenol, etc. are preferred. The anionic polymer is preferably poly(meth)acrylic acid or a salt thereof, or a copolymer containing (meth)acrylic acid or a salt thereof as a main component. Further, it is preferable that the crosslinking agent is at least one selected from the group consisting of a compound having a functional group such as an isocyanate group, a glycidyl group, a carboxyl group, or an oxazoline group, and a silane coupling agent. Moreover, it is preferable that the phosphoric acid or phosphate is a condensed phosphoric acid or a condensed phosphate.

An example of a corrosion-resistant film is to coat fine particles of barium sulfate or metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide in phosphoric acid on the surface of the barrier layer. Examples include those formed by performing baking treatment at temperatures above .degree.

The corrosion-resistant film may have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated, if necessary. Examples of the cationic polymer and anionic polymer include those mentioned above.

Note that the composition of the corrosion-resistant film can be analyzed using, for example, time-of-flight secondary ion mass spectrometry.

The amount of the corrosion-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly ^limited . is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg, in terms of chromium, the phosphorus compound is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg, in terms of phosphorus, and the aminated phenol polymer. It is desirable that the content is, for example, about 1.0 to 200 mg, preferably about 5.0 to 150 mg.

The thickness of the corrosion-resistant film is not particularly limited, but from the viewpoint of the cohesive force of the film and the adhesion with the barrier layer and the heat-fusible resin layer, it is preferably about 1 nm to 20 μm, more preferably 1 nm to 100 nm. More preferably, it is about 1 nm to 50 nm. The thickness of the corrosion-resistant film can be measured by observation using a transmission electron microscope, or by a combination of observation using a transmission electron microscope and energy dispersive X-ray spectroscopy or electron beam energy loss spectroscopy. Analysis of the composition of the corrosion-resistant film using time-of-flight secondary ion mass spectrometry reveals that, for example, secondary ions consisting of Ce, P, and O (for example, at least one of Ce ₂ PO ₄ ⁺ , CePO ₄ ^- , etc.) peaks derived from secondary ions (for example, at least one of CrPO ₂ ⁺ and CrPO ₄ ^- ) made of Cr, P, and O are detected.

Chemical conversion treatment involves applying a solution containing a compound used to form a corrosion-resistant film to the surface of the barrier layer using a bar coating method, roll coating method, gravure coating method, dipping method, etc., and then changing the temperature of the barrier layer. This is done by heating to a temperature of about 70 to 200°C. Furthermore, before the barrier layer is subjected to the chemical conversion treatment, the barrier layer may be previously subjected to a degreasing treatment using an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or the like. By performing the degreasing treatment in this manner, it becomes possible to perform the chemical conversion treatment on the surface of the barrier layer more efficiently. In addition, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for degreasing treatment, it is possible to not only degrease the metal foil but also form passive metal fluoride. In such cases, only degreasing treatment may be performed.

[Thermofusible resin layer 4]
In the exterior material for a power storage device of the present disclosure, the heat-fusible resin layer 4 corresponds to the innermost layer, and has a function of thermally fusing the heat-fusible resin layers to each other and sealing the power storage device element during assembly of the power storage device. This is a layer (sealant layer) that exhibits the following properties.

The resin constituting the heat-fusible resin layer 4 is not particularly limited as long as it can be heat-fusible, but resins containing a polyolefin skeleton such as polyolefin and acid-modified polyolefin are preferred. The fact that the resin constituting the heat-fusible resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like. Furthermore, when the resin constituting the heat-fusible resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride be detected. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected at wave numbers around 1760 cm ^-1 and around 1780 cm ^-1 wave numbers. When the heat-fusible resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected when measured by infrared spectroscopy. However, if the degree of acid modification is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specifically, the polyolefins include polyethylenes such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; ethylene-α olefin copolymers; homopolypropylene, block copolymers of polypropylene (for example, polyethylene and Examples include polypropylene such as block copolymers of ethylene), random copolymers of polypropylene (eg, random copolymers of propylene and ethylene); propylene-α-olefin copolymers; terpolymers of ethylene-butene-propylene, and the like. Among these, polypropylene is preferred. The polyolefin resin in the case of a copolymer may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more.

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

Acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of polyolefin with an acid component. As the acid-modified polyolefin, the aforementioned polyolefins, copolymers obtained by copolymerizing the aforementioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, or polymers such as crosslinked polyolefins can also be used. Further, examples of the acid component used for acid modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, or their anhydrides.

The acid-modified polyolefin may be an acid-modified cyclic polyolefin. Acid-modified cyclic polyolefin is a polymer obtained by copolymerizing some of the monomers constituting the cyclic polyolefin in place of the acid component, or by block polymerizing or graft polymerizing the acid component to the cyclic polyolefin. be. The cyclic polyolefin to be acid-modified is the same as described above. Further, the acid component used for acid modification is the same as the acid component used for modifying 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-fusible resin layer 4 may be formed from one type of resin alone, or may be formed from a blended polymer that is a combination of two or more types of resin. Furthermore, the heat-fusible resin layer 4 may be formed of only one layer, but may be formed of two or more layers of the same or different resins.

Further, the heat-fusible resin layer 4 may contain a lubricant or the like, if necessary. When the heat-fusible resin layer 4 contains a lubricant, the moldability of the exterior material for a power storage device can be improved. The lubricant is not particularly limited, and any known lubricant can be used. The lubricants may be used alone or in combination of two or more.

The lubricant is not particularly limited, but preferably includes an amide lubricant. Specific examples of the lubricant include those exemplified for the base layer 1. One type of lubricant may be used alone, or two or more types may be used in combination.

When a lubricant is present on the surface of the heat-fusible resin layer 4, its amount is not particularly limited, but from the viewpoint of improving the moldability of the exterior material for power storage devices, it is preferably about 10 to 50 mg/m ² More preferably, it is about 15 to 40 mg/m ² .

The lubricant present on the surface of the heat-fusible resin layer 4 may be one obtained by exuding a lubricant contained in the resin constituting the heat-fusible resin layer 4, or The surface may be coated with a lubricant.

Further, the thickness of the heat-fusible resin layer 4 is not particularly limited as long as the heat-fusible resin layers exhibit the function of thermally fusing each other and sealing the electricity storage device element, but is preferably about 100 μm or less, for example. The thickness is about 85 μm or less, more preferably about 15 to 85 μm. Note that, for example, when the thickness of the adhesive layer 5 described below is 10 μm or more, the thickness of the heat-fusible resin layer 4 is preferably about 85 μm or less, more preferably about 15 to 45 μm, for example. When the thickness of the adhesive layer 5 described below is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-fusible resin layer 4 is preferably about 20 μm or more, more preferably 35 to 85 μm. The degree is mentioned.

[Adhesive layer 5]
In the exterior material for a power storage device according to the present disclosure, the adhesive layer 5 is provided between the barrier layer 3 (or corrosion-resistant film (acid-resistant film, etc.)) and the heat-fusible resin layer 4 in order to firmly adhere them. This layer is provided as necessary.

The adhesive layer 5 is formed of a resin that can bond the barrier layer 3 and the heat-fusible resin layer 4 together. As the resin used for forming the adhesive layer 5, for example, the same adhesive as the adhesive exemplified for the adhesive layer 2 can be used. The resin used to form the adhesive layer 5 preferably contains a polyolefin skeleton, and examples thereof include the polyolefins and acid-modified polyolefins exemplified in the heat-fusible resin layer 4 described above. The fact that the resin constituting the adhesive layer 5 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, etc., and the analytical method is not particularly limited. Furthermore, when the resin constituting the adhesive layer 5 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride be detected. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected at wave numbers around 1760 cm ^-1 and around 1780 cm ^-1 wave numbers. However, if the degree of acid modification is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

From the viewpoint of firmly adhering the barrier layer 3 and the heat-fusible resin layer 4, the adhesive layer 5 preferably contains acid-modified polyolefin. As the acid-modified polyolefin, polyolefins modified with carboxylic acid or its anhydride, polypropylene modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefin, and maleic anhydride-modified polypropylene are particularly preferred.

Furthermore, from the viewpoint of reducing the thickness of the exterior material for power storage devices and making the exterior material for power storage devices excellent in shape stability after molding, the adhesive layer 5 is made of a resin composition containing acid-modified polyolefin and a curing agent. More preferably, it is a cured product of. Preferred examples of the acid-modified polyolefin include those mentioned above.

Further, the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. A cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of an isocyanate group-containing compound and an epoxy group-containing compound is particularly preferable. Further, the adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. As the polyester, for example, amide ester resin is preferable. Amide ester resins are generally produced by the reaction of carboxyl groups and oxazoline groups. The adhesive layer 5 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. Note that if unreacted substances of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remain in the adhesive layer 5, the presence of the unreacted substances can be detected by, for example, infrared spectroscopy, Confirmation can be performed by a method selected from Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

Further, from the viewpoint of further increasing the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is made of at least one selected from the group consisting of oxygen atoms, heterocycles, C=N bonds, and C-O-C bonds. It is preferable that it is a cured product of a resin composition containing one type of curing agent. Examples of the curing agent having a heterocycle include a curing agent having an oxazoline group, a curing agent having an epoxy group, and the like. Further, examples of the curing agent having a C=N bond include a curing agent having an oxazoline group, a curing agent having an isocyanate group, and the like. Further, examples of the curing agent having a C--O--C bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and polyurethane. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents can be achieved by, for example, gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF). -SIMS), X-ray photoelectron spectroscopy (XPS), and other methods.

The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively increasing the adhesion between the barrier layer 3 and the adhesive layer 5, polyfunctional isocyanate compounds are preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and these can be polymerized or nurated. Examples include polymers, mixtures thereof, and copolymers with other polymers. Further examples include adduct bodies, bullet bodies, isocyanurate bodies, and the like.

The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. It is more preferable to fall within this range. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively improved.

The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of compounds having an oxazoline group include those having a polystyrene main chain, and those having an acrylic main chain. Furthermore, commercially available products include, for example, the Epocross series manufactured by Nippon Shokubai Co., Ltd.

The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. It is more preferable that the Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively improved.

Examples of compounds having epoxy groups include epoxy resins. The epoxy resin is not particularly limited as long as it is a resin that can form a crosslinked structure by the epoxy groups present in the molecule, and any known epoxy resin can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2,000, more preferably about 100 to 1,000, and still more preferably about 200 to 800. Note that in the present disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

Specific examples of the epoxy resin include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether. One type of epoxy resin may be used alone, or two or more types may be used in combination.

The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. is more preferable. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively improved.

The polyurethane is not particularly limited, and any known polyurethane can be used. The adhesive layer 5 may be, for example, a cured product of two-part curable polyurethane.

The proportion of polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. More preferred. Thereby, it is possible to effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5 in an atmosphere where a component that induces corrosion of the barrier layer, such as an electrolytic solution, is present.

In addition, when the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin. , the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

The thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, about 5 μm or less. Further, the thickness of the adhesive layer 5 is preferably about 0.1 μm or more and about 0.5 μm or more. The range of the thickness is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, and 0.5 to about 5 μm. Examples include about 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, and about 0.5 to 5 μm. More specifically, in the case of the adhesive exemplified in adhesive layer 2 or a cured product of acid-modified polyolefin and a curing agent, the thickness is preferably about 1 to 10 μm, more preferably about 1 to 5 μm. Further, when using the resin exemplified for the heat-fusible resin layer 4, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. In addition, when the adhesive layer 5 is a cured product of the adhesive exemplified in the adhesive layer 2 or a resin composition containing an acid-modified polyolefin and a curing agent, for example, the resin composition is applied and cured by heating etc. By doing so, the adhesive layer 5 can be formed. Further, when using the resin exemplified for the heat-fusible resin layer 4, the heat-fusible resin layer 4 and the adhesive layer 5 can be formed by extrusion molding, for example.

[Surface coating layer 6]
The exterior material for a power storage device of the present disclosure is provided on the base material layer 1 (base material layer 1 A surface coating layer 6 may be provided on the opposite side of the barrier layer 3). The surface coating layer 6 is a layer located on the outermost layer side of the exterior material for a power storage device when the power storage device is assembled using the exterior material for a power storage device. As mentioned above, in the exterior material for a power storage device of the present disclosure, the b ^* value is -0.20 or less, so that the identification mark printed on the surface has excellent identifiability under a light source in a yellow room. The effect is demonstrated. However, although there are cases where the exterior material for an electricity storage device exhibits a slight blue color and color unevenness is visible, when the surface coating layer 6 is provided as the outermost layer of the exterior material for an energy storage device of the present disclosure, Since the layer has the effect of diffusing light and suppressing gloss, it has the advantage of suppressing the occurrence of color unevenness and improving the uniformity of appearance. On the other hand, when the outermost layer of the exterior material for a power storage device according to the present disclosure does not have the surface coating layer 6, the surface of the exterior material for a power storage device has high gloss and scratches are easily noticeable, but the surface coating layer 6 is not provided. In this case, the surface coating layer has the effect of diffusing light and suppressing gloss, so there is also the advantage that scratches are less noticeable. These advantages are particularly likely to be exhibited when the surface coating layer 6 contains the below-mentioned additives (particularly a matting agent).

In addition, in the exterior material for a power storage device of the present disclosure, the surface coating layer 6 is colored black to provide a exterior material for a power storage device with a black appearance, and the b ^* value is −0.20 or less. can be suitably set. However, similarly to the case where the adhesive layer 2 and the colored layer 21 described above are colored black, the b ^* value does not become −0.20 or less if the surface coating layer 6 is colored black. The composition, such as the type and content of the colorant contained in the surface coating layer 6, the base layer 1, and the layers located outside the barrier layer 3, such as the adhesive layer 2 and colored layer 21 provided as necessary. By adjusting the composition, furthermore, the aging treatment conditions of the exterior material for the electricity storage device, which will be described later, the appearance of the exterior material for the energy storage device is made black, and the b ^* value is set to -0.20 or less. Can be done. The same applies to the setting of the L ^* value and the a ^* value.

The surface coating layer 6 can be formed of a resin such as polyvinylidene chloride, polyester, polyurethane, acrylic resin, or epoxy resin.

When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-liquid curing type or a two-liquid curing type, but preferably a two-liquid curing type. Examples of the two-part curable resin include two-part curable polyurethane, two-part curable polyester, and two-part curable epoxy resin. Among these, two-component curing polyurethane is preferred.

Examples of the two-component curable polyurethane include polyurethane containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred examples include two-component curing polyurethanes that use polyols such as polyester polyols, polyether polyols, and acrylic polyols as main ingredients and aromatic or aliphatic polyisocyanates as curing agents. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in the side chain in addition to the hydroxyl group at the end of the repeating unit. Examples of the curing agent include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. 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), naphthalene diisocyanate (NDI), and the like. Also included are polyfunctional isocyanate modified products of one or more of these diisocyanates. It is also possible to use multimers (for example trimers) as the polyisocyanate compound. Such multimers include adducts, biurets, nurates, and the like. Since the surface coating layer 6 is formed of polyurethane, excellent electrolyte resistance is imparted to the exterior material for the electricity storage device.

The surface coating layer 6 may contain the above-mentioned lubricant or coloring agent on at least one of the surface and inside of the surface coating layer 6, depending on the functionality to be provided to the surface coating layer 6 and its surface. , an anti-blocking agent, a matting agent, a flame retardant, an antioxidant, a tackifier, an antistatic agent, and other additives. Examples of the additive include fine particles having an average particle diameter of about 0.5 nm to 5 μm. The average particle diameter of the additive is the median diameter measured by a laser diffraction/scattering particle size distribution measuring device.

The additive may be either inorganic or organic. Further, the shape of the additive is not particularly limited, and examples include spherical, fibrous, plate-like, amorphous, and scaly shapes.

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, Examples include crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. The additives may be used alone or in combination of two or more. Among these additives, calcium carbonate is preferably used from the viewpoint of improving identifiability. Since calcium carbonate has a bluish tinge, by using it as an additive in the surface coating layer, the b ^* value can be suitably set to -0.20 or less. Further, it is preferable to use a mixture of silica and calcium carbonate as additives. By using silica as an additive in the surface coating layer, reflected light can be easily diffused and the appearance of the exterior material for power storage devices can be given a more bluish tinge, reducing the b ^* value to -0.20. It can be suitably set as follows. Among these additives, from the viewpoint of dispersion stability and cost, silica, barium sulfate, and titanium oxide are preferred. Further, the additive may be subjected to various surface treatments such as insulation treatment and high dispersion treatment.

When the surface coating layer 6 contains a colorant, known colorants such as pigments and dyes can be used as the colorant. Moreover, only one type of coloring agent may be used, or two or more types of coloring agents may be used in combination. Specific examples of the colorant contained in the surface coating layer 6 include the same ones as those exemplified in the section of [Adhesive layer 2]. Moreover, the preferable content of the colorant contained in the surface coating layer 6 is also the same as the content described in the column of [Adhesive layer 2].

For example, when a black agent is added to the surface coating layer 6, the content of the black agent in the surface coating layer 6 is not particularly limited as long as the exterior material for the electricity storage device is colored black, and is, for example, 5 to 60% by mass. degree, preferably 10 to 40% by mass. Further, when a blue agent is added to the surface coating layer 6, the content of the blue agent in the surface coating layer 6 is not particularly limited as long as the exterior material for the electricity storage device is colored black; for example, 0.5 to 30 About 1% by mass, preferably 1 to 20% by mass.

Further, for example, when blending a black agent and a blue agent in the surface coating layer 6, the proportion of the black agent and the blue agent in the surface coating layer 6 is preferably 100 parts by mass, and the proportion of the blue agent is preferably The amount is about 0.1 parts by weight or more, more preferably about 1 part by weight or more, and still more preferably about 10 parts by weight or more. Further, the proportion of the blue agent is preferably about 150 parts by mass or less, more preferably about 100 parts by mass or less. Further, the preferable range of the blue agent is about 0.1 to 150 parts by weight, about 0.1 to 100 parts by weight, about 1 to 150 parts by weight, about 1 to 100 parts by weight, about 10 to 150 parts by weight, The amount is about 10 to 100 parts by mass.

The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a resin that forms the surface coating layer 6. When adding additives to the surface coating layer 6, a resin mixed with the additives may be applied.

The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above-mentioned function as the surface coating layer 6, and may be, for example, about 0.5 to 10 μm, preferably about 1 to 5 μm.

For example, when the adhesive layer is a layer colored black, the surface coating layer located outside the adhesive layer is preferably transparent or translucent.

3. Method for manufacturing exterior material for power storage device The method for manufacturing the exterior material for power storage device is not particularly limited as long as a laminate in which each layer included in the exterior material for power storage device of the present disclosure is laminated can be obtained. A method may include a step of laminating layer 1, barrier layer 3, and heat-fusible resin layer 4 in this order. Specifically, the method for manufacturing an exterior material for a power storage device of the present disclosure is a method for manufacturing an exterior material for a power storage device that has a black appearance, and includes, in order from the outside, at least a base layer, a barrier layer, ^L The b ^* value in the a ^* b ^* color space is -0.20 or less.

An example of the method for manufacturing the exterior material for a power storage device according to the present disclosure is as follows. First, a laminate (hereinafter sometimes referred to as "laminate A") in which a base material layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order is formed. Specifically, the formation of the laminate A is performed by applying the adhesive used for forming the adhesive layer 2 on the base layer 1 or on the barrier layer 3 whose surface has been subjected to a chemical conversion treatment as necessary, using a gravure coating method, It can be carried out by a dry lamination method in which the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after coating and drying by a coating method such as a roll coating method.

Next, a heat-fusible resin layer 4 is laminated on the barrier layer 3 of the laminate A. When the heat-fusible resin layer 4 is directly laminated on the barrier layer 3, the heat-fusible resin layer 4 is laminated on the barrier layer 3 of the laminate A by a method such as a thermal lamination method or an extrusion lamination method. do it. In addition, when providing the adhesive layer 5 between the barrier layer 3 and the heat-fusible resin layer 4, for example, (1) the adhesive layer 5 and the heat-fusible resin layer are provided on the barrier layer 3 of the laminate A. 4 (coextrusion lamination method, tandem lamination method), (2) Separately, a laminate is formed by laminating the adhesive layer 5 and the heat-fusible resin layer 4, and this is laminate A. A method of laminating the adhesive layer 5 on the barrier layer 3 of the laminate A by a thermal laminating method, or forming a laminate in which the adhesive layer 5 is laminated on the barrier layer 3 of the laminate A, and then laminating this with the heat-fusible resin layer 4 by a thermal laminating method. Lamination method (3) While pouring the molten adhesive layer 5 between the barrier layer 3 of the laminate A and the heat-fusible resin layer 4 formed into a sheet in advance, the adhesive layer 5 is laminated. (4) solution coating the barrier layer 3 of the laminate A with an adhesive to form the adhesive layer 5; For example, the adhesive layer 5 may be laminated by a drying method or a baking method, and a heat-fusible resin layer 4 previously formed in a sheet shape may be laminated on the adhesive layer 5.

When providing the surface coating layer 6, the surface coating layer 6 is laminated on the surface of the base material layer 1 on the side opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above resin for forming the surface coating layer 6 onto the surface of the base material layer 1. Note that the order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 on the opposite side to the surface coating layer 6.

As described above, in order from the outside: surface coating layer 6 provided as necessary/base layer 1/adhesive layer 2 provided as necessary/barrier layer 3/adhesive layer 5 provided as necessary. / A laminate including the heat-fusible resin layer 4 is formed, but in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as necessary, it may be further subjected to heat treatment. good.

In the exterior material for a power storage device, each layer constituting the laminate may be subjected to surface activation treatment such as corona treatment, blasting treatment, oxidation treatment, or ozone treatment to improve processing suitability, if necessary. . For example, by subjecting the surface of the base layer 1 opposite to the barrier layer 3 to a corona treatment, the printability of the ink on the surface of the base layer 1 can be improved.

The exterior material for a power storage device is preferably subjected to an aging treatment after each layer is laminated. By changing the aging treatment conditions of the exterior material for a power storage device, it is possible to change the L ^* value, a ^* value, and b ^* value of the exterior material for a power storage device that has a black appearance. Therefore, it is preferable to select aging processing conditions for the purpose of adjusting the L ^* value, the a ^* value, and the b ^* value. Adjustment items for aging treatment conditions include, for example, temperature increase rate, heating temperature, heating time, presence or absence of pretreatment, and its temperature. The main reason why the L ^* value, a ^* value, and b ^* value change depending on the aging treatment conditions is that the degree of aggregation of the colorant contained in the exterior material for electricity storage devices changes depending on the aging treatment conditions. It will be done.

4. Application of exterior packaging material for power storage devices The exterior packaging material for power storage devices of the present disclosure is used for a package for sealing and accommodating power storage device elements such as a positive electrode, a negative electrode, and an electrolyte. That is, a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed of the exterior material for a power storage device according to the present disclosure to form a power storage device.

Specifically, an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is prepared using the exterior material for an electricity storage device of the present disclosure, with metal terminals connected to each of the positive electrode and the negative electrode protruding outward. , Covering the electricity storage device element so that a flange portion (an area where the heat-fusible resin layers contact each other) is formed around the periphery of the power storage device element, and sealing the heat-fusible resin layers of the flange portion by heat-sealing each other. provides an electricity storage device using an exterior material for an electricity storage device. Note that when a power storage device element is housed in a package formed of the power storage device exterior material of the present disclosure, the heat-fusible resin portion of the power storage device exterior material of the present disclosure is placed on the inside (the surface in contact with the power storage device element). ) to form a package.

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

The present disclosure will be explained in detail by showing Examples and Comparative Examples below. However, the present disclosure is not limited to the examples.

<Manufacture of exterior materials for power storage devices>
Examples 1-7, 14, 15 and Comparative Example 1
A stretched nylon (ONy) film (thickness: 15 μm) was prepared as a base material layer. Further, an aluminum foil (JIS H4160:1994 A8021H-O (thickness: 35 μm)) was prepared as a barrier layer. Next, the barrier layer and the base material layer are laminated by a dry lamination method using an adhesive (a two-component urethane adhesive containing a colorant) to be described later, and then an aging treatment is performed to form the base material layer. A laminate of /adhesive layer/barrier layer was produced. Both sides of the aluminum foil are chemically treated. For chemical conversion treatment of aluminum foil, a treatment solution consisting of phenol resin, chromium fluoride compound, and phosphoric acid is coated on both sides of aluminum foil using a roll coating method so that the coating amount of chromium is 10 mg/m ² (dry mass). This was done by coating and baking.

Next, on the barrier layer of each laminate obtained above, maleic anhydride-modified polypropylene as an adhesive layer (thickness 20 μm) and random polypropylene as a heat-fusible resin layer (thickness 20 μm) were added. By co-extruding, an adhesive layer/thermal adhesive resin layer was laminated on the barrier layer. Furthermore, a resin composition containing silica particles (the resin is a polyurethane resin formed from a mixture of a polyol compound and an isocyanate compound) is applied to the surface of the base material layer of the obtained laminate to a thickness of 3 μm. By processing, a matte-like surface coating layer is formed, and in order from the outside: surface coating layer (3 μm) / base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesion. A laminate (total thickness 96 μm) in which layer (20 μm)/thermal adhesive resin layer (20 μm) was laminated was obtained.

Example 8
In Example 1, in the same manner as in Example 1, except that no surface coating layer was formed, base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer ( A laminate (total thickness: 93 μm) was obtained in which a layer (20 μm)/a heat-fusible resin layer (20 μm) was laminated.

Example 9
In Example 3, in the same manner as in Example 3, except that no surface coating layer was formed, base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer ( A laminate (total thickness: 93 μm) was obtained in which a layer (20 μm)/a heat-fusible resin layer (20 μm) was laminated.

Example 10
In Example 4, in the same manner as in Example 4, except that no surface coating layer was formed, base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer ( A laminate (total thickness: 93 μm) was obtained in which a layer (20 μm)/a heat-fusible resin layer (20 μm) was laminated.

Example 11
In Example 5, in the same manner as in Example 5, except that no surface coating layer was formed, base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer ( A laminate (total thickness: 93 μm) was obtained in which a layer (20 μm)/a heat-fusible resin layer (20 μm) was laminated.

Example 12
In Example 2, in the same manner as in Example 2, except that no surface coating layer was formed, base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer ( A laminate (total thickness: 93 μm) was obtained in which a layer (20 μm)/a heat-fusible resin layer (20 μm) was laminated.

Examples 13, 16-20
In Example 1, no surface coating layer was formed, and adhesives B and C4 to C8 listed in Table 1 were used instead of adhesive A as the adhesive used to form the adhesive layer. Other than that, in the same manner as in Example 1, base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-fusible resin layer (20 μm) were prepared. A laminated body (total thickness: 93 μm) was obtained.

<Adhesive>
The following adhesive was used to form the adhesive layer between the base material layer and the barrier layer. Table 1 shows the types of adhesives used in each example and comparative example.
[Adhesive A]
Two-component urethane adhesive (mixture of polyol compound and aromatic isocyanate compound) containing carbon black (secondary particle size 0.2 μm) as a black agent
[Adhesive B]
A two-component urethane adhesive (polyol compound and aromatic isocyanate compound) that contains carbon black with a primary particle size larger than the carbon black contained in adhesive A (secondary particle size 0.2 μm) as a black agent. mixture)
[Adhesive C1]
The same carbon black as that contained in Adhesive A was used as the black agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 4 parts by mass of copper phthalocyanine as a blue agent based on 26 parts by mass of carbon black.
[Adhesive C2]
The same carbon black as that contained in Adhesive A was used as the black agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 15 parts by mass of copper phthalocyanine as a blue agent based on 15 parts by mass of carbon black.
[Adhesive C3]
The same carbon black as that contained in Adhesive A was used as the black agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 17 parts by mass of copper phthalocyanine as a blue agent based on 13 parts by mass of carbon black.
[Adhesive C4]
The same carbon black as that contained in Adhesive A was used as the black agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 10 parts by mass of copper phthalocyanine as a blue agent based on 20 parts by mass of carbon black.
[Adhesive C5]
The same carbon black as that contained in Adhesive A was used as the black agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 12 parts by mass of copper phthalocyanine as a blue agent based on 18 parts by mass of carbon black.
[Adhesive C6]
The same carbon black as that contained in Adhesive A was used as the black agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 8 parts by mass of copper phthalocyanine as a blue agent based on 22 parts by mass of carbon black.
[Adhesive C7]
The same carbon black as that contained in Adhesive A was used as the black agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 14 parts by mass of copper phthalocyanine as a blue agent based on 16 parts by mass of carbon black.
[Adhesive C8]
The same carbon black as that contained in Adhesive A was used as the black agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 16 parts by mass of copper phthalocyanine as a blue agent based on 14 parts by mass of carbon black.

<Aging treatment conditions>
The aging treatment conditions used to adjust the color observed from the outside of the exterior materials for power storage devices manufactured in each example and comparative example are as follows.
[Condition A]
Let stand in an 80°C environment for 12 hours.
[Condition B]
First, in step 1, the sample is left standing at room temperature (approximately 25° C.) for 3 hours. Next, as step 2, the product is left standing in a 55° C. environment for 3 hours. Next, in step 3, the product is left standing in an 80° C. environment for 12 hours.
[Condition C]
Let stand for 3 days in an environment of 60°C to 100°C.

<Measurement of L ^* value, a ^* value and b ^* value>
Regarding the exterior materials for power storage devices obtained in each example and comparative example, the observation conditions of a spectrophotometer (CM-700d) manufactured by Konica Minolta, calibrated with a white calibration cap (CM-A177, manufactured by Konica Minolta) were set to 10 The observation light source was set to F2 and SCI mode (JIS Z8722-2009), and L ^* , a ^* , and b ^* of the outer (substrate layer side) surface were measured at room temperature and humidity. Measurements were made at three points for each sample, and the average value is shown in Table 1 as the evaluation results.

<Measurement of Cu element by X-ray fluorescence analysis (XRF)>
Regarding the exterior materials for power storage devices obtained in Examples 1 to 5 and Comparative Example 1, the presence or absence of detection of Cu element by X-ray fluorescence analysis (XRF) was confirmed under the following measurement conditions. As a result, in Examples 1 and 2 and Comparative Example 1, no peak derived from the Cu element was detected. Moreover, in Examples 3, 4, and 5, a peak derived from the Cu element was detected. Note that the peak intensity of CuKα was 0.4 in Example 3, 1.2 in Example 4, and 1.2 in Example 5.
(Measurement condition)
Equipment used: EDX-800HS (manufactured by Shimadzu Corporation)
X-ray: Rh target voltage: 50kV
Current: 1000μA
Irradiation area: 100φ
Measurement time: 100sec
Measurement atmosphere: Vacuum Measurement surface: Outside (X-rays are irradiated on the outside of the exterior material for the power storage device)
Analysis method: Perform automatic strength calculation using the software "PCEDX" included with EDX-800HS (manufactured by Shimadzu Corporation). Specifically, peak detection is performed on the spectrum obtained by measurement. The coefficient of the peak detection condition is set to 10. Next, the detected intensity is calculated from the intensity calculation for the detected peak.

<Identification in the yellow room>
Using an inkjet printer (model name 9040, manufactured by Markem Image Co., Ltd.), a dot with a diameter of about 0.3 mm was printed on the surface of the surface coating layer of the exterior material for power storage devices obtained in each example and comparative example. A numeric string "0123456789" with a character string height of approximately 1.5 mm was printed as a sample. Note that the ink used for printing was white. Next, each sample was observed with the naked eye from a position 30 cm away in a yellow room, and the distinguishability was evaluated according to the following evaluation criteria. The results are shown in Table 1.
(Evaluation criteria)
A: Immediate recognition B: Recognition takes several seconds C: Recognition possible by changing the sample angle

<Black exterior>
In a room under fluorescent lighting, each sample prepared in the above <Identification in a Yellow Room> was observed with the naked eye and evaluated for its appearance as black according to the evaluation criteria below. . The results are shown in Table 1.
(Evaluation criteria)
A: It is clearly recognized as black.
B: Blue or red is slightly recognized, but it is recognized as black without any problem.C: Blue or red is clearly recognized, and there is a possibility that it will not be recognized as black.

As is clear from the results shown in Table 1, the exterior materials for power storage devices of Examples 1 to 20 have L ^* a of reflected light measured from the outside under the measurement conditions of SCI method, field of view 10°, and light source F2. ^* Since ^{the b * value} in the color space is -0.20 or less, the identification mark printed on the surface in the yellow room is It can be seen that the identifiability is excellent. In addition, the exterior materials for power storage devices of Examples 1 to 20 had excellent identifiability of the identification mark printed on the surface not only in a yellow room but also in a room under general fluorescent lighting. In addition, the exterior materials for power storage devices of Examples 1 to 20 could be recognized as black in appearance indoors under general fluorescent lighting without any problem.

As described above, the present disclosure provides inventions of the following aspects.
Item 1. An exterior material for a power storage device having a black appearance,
The exterior material for a power storage device is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-fusible resin layer,
A battery whose b ^* value in the L ^* a ^* b ^* color space of reflected light measured from the outside of the laminate under the measurement conditions of SCI method, field of view of 10°, and light source F2 is −0.20 or less. Exterior material for devices.
Item 2. Item 1, wherein the a ^* value in the L ^* a ^* b ^* color space of the reflected light measured from the outside of the laminate under the measurement conditions of the SCI method, field of view 10°, and light source F2 is +0.2 or less. The exterior material for an electricity storage device described in .
Item 3. An adhesive layer is provided between the base layer and the barrier layer,
Item 3. The exterior packaging material for a power storage device according to item 1 or 2, wherein the adhesive layer contains a colorant. Item 4. A colored layer is provided between the base layer and the barrier layer,
Item 4. The exterior material for a power storage device according to any one of Items 1 to 3, wherein the colored layer contains a pigment.
Item 5. Item 5. The exterior packaging material for a power storage device according to any one of Items 1 to 4, further comprising a surface coating layer on a side of the base material layer opposite to the barrier layer side.
Item 6. Item 6. The exterior packaging material for a power storage device according to any one of Items 1 to 5, wherein Cu element is detected when analysis is performed from the outside of the laminate using fluorescent X-ray analysis.
Section 7. A method for manufacturing an exterior material for a power storage device having a black appearance, the method comprising:
A step of obtaining a laminate in which at least a base material layer, a barrier layer, and a heat-fusible resin layer are laminated in order from the outside,
A battery whose b ^* value in the L ^* a ^* b ^* color space of reflected light measured from the outside of the laminate under the measurement conditions of SCI method, field of view of 10°, and light source F2 is −0.20 or less. A method for manufacturing an exterior material for a device.
Section 8. An electricity storage device, wherein an electricity storage device element comprising at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for an electricity storage device according to any one of Items 1 to 6.

1 Base material layer 2 Adhesive layer 21 Colored layer 3 Barrier layer 4 Heat-fusible resin layer 5 Adhesive layer 6 Surface coating layer 10 Exterior material for power storage device

Claims (17)

An exterior material for a power storage device having a black appearance,
The exterior material for a power storage device is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-fusible resin layer,
The b ^* value in the L ^* a ^* b ^* color space of the reflected light measured from the outside of the laminate under the measurement conditions of the SCI method, 10° field of view, and light source F2 is -0.20 or less,
An exterior material for a power storage device, wherein the L ^* value of reflected light in the L ^* a ^* b ^* color space is 26.0 or more . Claim: The a ^* value of the reflected light in the L ^* a ^* b ^* color space measured from the outside of the laminate under the measurement conditions of the SCI method, 10° field of view, and light source F2 is +0.20 or less. The exterior material for an electricity storage device according to item 1. An adhesive layer is provided between the base layer and the barrier layer,
The exterior material for a power storage device according to claim 1 or 2, wherein the adhesive layer contains a colorant. A colored layer is provided between the base layer and the barrier layer,
The exterior material for a power storage device according to any one of claims 1 to 3, wherein the colored layer contains a pigment. The exterior material for a power storage device according to any one of claims 1 to 4, further comprising a surface coating layer on a side of the base material layer opposite to the barrier layer side. The exterior packaging material for a power storage device according to any one of claims 1 to 5, wherein Cu element is detected when analysis is performed from the outside of the laminate using fluorescent X-ray analysis. The exterior material for an electricity storage device according to any one of claims 1 to 6 , wherein the b ^* value of the reflected light in the L ^* a ^* b ^* color space is -1.20 or more. The exterior material for a power storage device according to any one of claims 1 to 7 , wherein the a ^* value of the reflected light in the L ^* a ^* b ^* color space is -0.07 or more. A lubricant is present on the surface of the heat-fusible resin layer,
The exterior material for a power storage device according to any one of claims 1 to 8 , wherein the amount of the lubricant is 10 mg/m ² or more. The exterior material for an electricity storage device according to any one of claims 1 to 9 , wherein two or more types of lubricants are present on at least one of the surface and inside of the heat-fusible resin layer. At least one of the surface and the interior of the heat-fusible resin layer contains a saturated fatty acid amide, an unsaturated fatty acid amide, a substituted amide, a methylolamide, a saturated fatty acid bisamide, an unsaturated fatty acid bisamide, a fatty acid ester amide, and an aromatic bisamide. The exterior packaging material for an electricity storage device according to any one of claims 1 to 10 , wherein at least two or more types selected from the group are present. A surface coating layer is provided on the side opposite to the barrier layer of the base layer,
The exterior material for an electricity storage device according to any one of claims 1 to 11 , wherein a lubricant is present on at least one of the surface and inside of the surface coating layer. A surface coating layer is provided on the side opposite to the barrier layer of the base layer,
The exterior material for an electricity storage device according to any one of claims 1 to 12 , wherein two or more types of lubricants are present on at least one of the surface and inside of the surface coating layer. A surface coating layer is provided on the side opposite to the barrier layer of the base layer,
At least one of the surface and inside of the surface coating layer contains a compound selected from the group consisting of saturated fatty acid amide, unsaturated fatty acid amide, substituted amide, methylolamide, saturated fatty acid bisamide, unsaturated fatty acid bisamide, fatty acid ester amide, and aromatic bisamide. The exterior packaging material for an electricity storage device according to any one of claims 1 to 13 , wherein at least two or more of the following are present. A method for manufacturing an exterior material for a power storage device having a black appearance, the method comprising:
A step of obtaining a laminate in which at least a base material layer, a barrier layer, and a heat-fusible resin layer are laminated in order from the outside,
The b ^* value in the L ^* a ^* b ^* color space of the reflected light measured from the outside of the laminate under the measurement conditions of the SCI method, 10° field of view, and light source F2 is -0.20 or less,
A method for manufacturing an exterior material for a power storage device, wherein the L ^* value of reflected light in the L ^* a ^* b ^* color space is 26.0 or more . An adhesive layer is provided between the barrier layer and the heat-fusible resin layer,
The barrier layer and the heat-fusible resin layer are formed by a coextrusion lamination method, a tandem lamination method, a thermal lamination method, a sandwich lamination method, or by applying a solution of an adhesive for forming the adhesive layer on the barrier layer. 16. The method for manufacturing an exterior material for an electricity storage device according to claim 15 , which is formed by a method of coating and laminating the heat-fusible resin layer previously formed into a sheet on the adhesive layer. An electricity storage device, wherein an electricity storage device element comprising at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for an electricity storage device according to any one of claims 1 to 14 .

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