JP7790455B2 - Exterior material for power storage device, manufacturing method thereof, and power storage device - Google Patents

Description

This disclosure relates to an exterior material for an electricity storage device, a method for manufacturing the same, and an electricity storage device.

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

On the other hand, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and other devices, there has been a demand for energy storage devices to be thinner and lighter, as well as have a variety of shapes. However, the metal exterior materials for energy storage devices that have traditionally been widely used have the drawback of being difficult to adapt to the increasing variety of shapes, and there are also limitations to how light they can be made.

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

In such electrical storage device packaging materials, recesses are generally formed by cold forming, and electrical storage device elements such as electrodes and electrolyte are placed in the spaces formed by the recesses. The heat-sealable resin layer is then heat-sealed to obtain an electrical storage device in which the electrical storage device elements are housed inside the electrical storage device packaging material.

Japanese Patent Application Laid-Open No. 2008-287971

Since the exterior materials for electricity storage devices made from the aforementioned film-like laminates are softer and more susceptible to surface scratches than metal exterior materials, it is desirable to improve their scratch resistance. One way to improve the scratch resistance of exterior materials for electricity storage devices is to provide a hard layer containing inorganic particles such as silica particles as a scratch-resistant layer on the outer side of the base material layer.

However, as mentioned above, in electrical storage device exterior materials, recesses are generally formed by cold forming. Therefore, providing a hard scratch-resistant layer containing inorganic particles such as silica particles on the outer side of the base layer increases scratch resistance, but reduces formability. In particular, there is a problem in that the hard scratch-resistant layer is prone to cracking at the corners of the recesses formed by forming the electrical storage device exterior material. Therefore, it has been difficult to achieve both excellent scratch resistance and excellent formability in electrical storage device exterior materials using a method that provides a scratch-resistant layer containing inorganic particles such as silica particles.

In light of these circumstances, the primary objective of this disclosure is to provide an exterior material for an electricity storage device that exhibits excellent formability despite being endowed with excellent scratch resistance by a scratch-resistant layer.

The inventors of the present disclosure conducted extensive research to solve the above-mentioned problems. As a result, they discovered that by providing a scratch-resistant layer containing inorganic particles and a resin on the surface of an exterior material for an electricity storage device, and further disposing a substrate protective layer between the scratch-resistant layer and the substrate layer, and setting the average film thickness of the scratch-resistant layer and the substrate protective layer together to 10 μm or less, the scratch-resistant layer imparts excellent scratch resistance, and also effectively suppresses cracking of the scratch-resistant layer during molding of the exterior material for an electricity storage device.

The present disclosure has been completed based on these findings and further investigations. That is, the present disclosure provides the inventions of the following aspects.
The laminate is composed of at least a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-sealable resin layer, in this order;
the scratch-resistant layer contains inorganic particles and a resin,
The exterior material for an electricity storage device, wherein the average film thickness of the scratch-resistant layer and the base material protective layer combined is 10 μm or less.

The present disclosure makes it possible to provide an exterior material for an electricity storage device that has excellent scratch resistance and formability. The present disclosure also makes it possible to provide a method for manufacturing the exterior material for an electricity storage device, and an electricity storage device that uses the exterior material for an electricity storage device.

1 is a schematic diagram showing an example of a cross-sectional structure of an exterior packaging material for an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior packaging material for an electricity storage device according to the present disclosure. 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior packaging material for an electricity storage device according to the present disclosure. 1 is a diagram schematically showing a cross section in the thickness direction of a scratch-resistant layer and a substrate protective layer of an exterior packaging material for an electricity storage device according to the present disclosure, observed with a scanning electron microscope. FIG.

The electrical storage device packaging material of the present disclosure is composed of a laminate including at least a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-sealable resin layer, in this order; the scratch-resistant layer contains inorganic particles and a resin; and the average film thickness of the scratch-resistant layer and the substrate protective layer combined is 10 μm or less. By having this configuration, the electrical storage device packaging material of the present disclosure can achieve both excellent scratch resistance and excellent formability.

The exterior packaging material for an electricity storage device disclosed herein is described in detail below. Note that in this specification, numerical ranges indicated by "to" mean "greater than or equal to" or "less than or equal to." For example, the expression "2 to 15 mm" means 2 mm or greater and 15 mm or less.

1. Laminated Structure of Electricity Storage Device Exterior Material As shown in Figures 1 to 3, for example, an electricity storage device exterior material 10 according to the present disclosure is composed of a laminate including at least a scratch-resistant layer 7, a substrate protective layer 6, a substrate layer 1, a barrier layer 3, and a heat-sealable resin layer 4. In the electricity storage device exterior material 10, the scratch-resistant layer 7 is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. When assembling an electricity storage device using the electricity storage device exterior material 10 and an electricity storage device element, the heat-sealable resin layers 4 of the electricity storage device exterior material 10 are placed opposite each other, and the electricity storage device element is housed in a space formed by heat-sealing the peripheral portions.

As shown in Figures 2 and 3, the exterior packaging material 10 for an electricity storage device may optionally have an adhesive layer 2 between the base layer 1 and the barrier layer 3 to enhance adhesion between these layers. Also, as shown in Figure 3, for example, an adhesive layer 5 may optionally be provided between the barrier layer 3 and the heat-sealable resin layer 4 to enhance adhesion between these layers.

The thickness of the laminate constituting the electrical storage device exterior material 10 is not particularly limited, but from the viewpoints of cost reduction, improved energy density, etc., it is preferably about 180 μm or less, about 155 μm or less, or about 120 μm or less. Furthermore, from the viewpoint of maintaining the function of the electrical storage device exterior material (10) of protecting the electrical storage device elements, the thickness of the laminate constituting the electrical storage device exterior material 10 is preferably about 35 μm or more, about 45 μm or more, or about 60 μm or more. Furthermore, preferred ranges for the thickness of the laminate constituting the electrical storage device exterior material 10 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, about 45 to 120 μm, about 60 to 180 μm, about 60 to 155 μm, and about 60 to 120 μm, with about 60 to 155 μm being particularly preferred. The thickness of the laminate constituting the electrical storage device exterior material 10 is the sum of the average film thickness of the scratch-resistant layer 7 and the substrate protective layer 6 and the total film thickness of the layers other than the scratch-resistant layer 7 and the substrate protective layer 6.

In the electrical storage device exterior material 10, the ratio of the total thickness of the scratch-resistant layer 7, substrate protective layer 6, substrate layer 1, optional adhesive layer 2, barrier layer 3, optional adhesive layer 5, and heat-sealable resin layer 4 to the thickness (total thickness) of the laminate constituting the electrical storage device exterior material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the electrical storage device exterior material 10 of the present disclosure includes the scratch-resistant layer 7, substrate protective layer 6, substrate layer 1, adhesive layer 2, barrier layer 3, adhesive layer 5, and heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the electrical storage device exterior material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, even when the electrical storage device packaging material 10 of the present disclosure includes a scratch-resistant layer 7, a substrate protective layer 6, a substrate layer 1, an adhesive layer 2, a barrier layer 3, and a heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

2. Layers forming the exterior material for an electricity storage device [scratch-resistant layer 7]
The exterior packaging material 10 for an electricity storage device according to the present disclosure has a scratch-resistant layer 7 on its outer surface for the purpose of improving scratch resistance, etc. The scratch-resistant layer 7 is a layer located as the outermost layer of the exterior packaging material 10 for an electricity storage device when the exterior packaging material 10 for an electricity storage device is used to assemble an electricity storage device.

The scratch-resistant layer 7 contains inorganic particles 71 and a resin. That is, the scratch-resistant layer 7 is formed from a resin composition containing inorganic particles 71 and a resin. Furthermore, the average film thickness of the scratch-resistant layer 7 and the substrate protective layer 6 (described below) combined is set to 10 μm or less.

Examples of inorganic particles 71 include silica, talc, 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, gold, aluminum, copper, and nickel. Among these, silica particles are particularly preferred from the viewpoint of achieving both excellent scratch resistance and excellent formability. The inorganic particles 71 contained in the scratch-resistant layer 7 may be of one type or two or more types.

The shape of the inorganic particles 71 is not particularly limited, and examples include spherical, fibrous, plate-like, irregular, and scaly shapes, with spherical shapes being preferred.

The average particle size of the inorganic particles 71 is, for example, approximately 0.5 nm to 5 μm, preferably approximately 0.5 to 3 μm, from the viewpoint of achieving both excellent scratch resistance and excellent moldability.

The average particle diameter of the inorganic particles 71 is the median diameter measured using a laser diffraction/scattering particle size distribution measuring device.

From the viewpoint of optimally achieving both excellent scratch resistance and excellent moldability, the content of inorganic particles 71 contained in scratch-resistant layer 7 is preferably at least about 0.1 part by mass, more preferably at least about 0.5 part by mass, and even more preferably at least about 1.0 part by mass, per 100 parts by mass of the resin. From the same viewpoint, the content of inorganic particles 71 contained in scratch-resistant layer 7 is preferably no more than about 10.0 parts by mass, more preferably no more than about 5.0 parts by mass, and even more preferably no more than about 3.0 parts by mass. Preferred ranges for the content of inorganic particles 71 contained in scratch-resistant layer 7 include approximately 0.1 to 10.0 parts by mass, approximately 0.1 to 5.0 parts by mass, approximately 0.1 to 3.0 parts by mass, approximately 0.5 to 10.0 parts by mass, approximately 0.5 to 5.0 parts by mass, approximately 0.5 to 3.0 parts by mass, approximately 1.0 to 10.0 parts by mass, approximately 1.0 to 5.0 parts by mass, and approximately 1.0 to 3.0 parts by mass.

From the perspective of optimally achieving both excellent scratch resistance and excellent formability, it is preferable that the scratch-resistant layer 7 further contains organic particles 72 in addition to the inorganic particles 71. Examples of organic particles 72 include organic particles of nylon, polyacrylate, polystyrene, styrene-acrylic copolymer, polyethylene, benzoguanamine, or crosslinked products thereof. The scratch-resistant layer 7 may contain one type of organic particle 72, or two or more types.

From the viewpoint of achieving both excellent scratch resistance and excellent formability, the particle diameter of the organic particles 72 is preferably approximately 5.0 μm or less, more preferably approximately 3.0 μm or less, and even more preferably approximately 2.0 μm or less. From the same viewpoint, the particle diameter of the organic particles 72 is preferably approximately 0.3 μm or more, more preferably approximately 0.5 μm or more, and even more preferably approximately 1.0 μm or more. Preferred particle diameter ranges for the organic particles 72 include approximately 0.3 to 5.0 μm, approximately 0.3 to 3.0 μm, approximately 0.3 to 2.0 μm, approximately 0.5 to 5.0 μm, approximately 0.5 to 3.0 μm, approximately 0.5 to 2.0 μm, approximately 1.0 to 5.0 μm, approximately 1.0 to 3.0 μm, and approximately 1.0 to 2.0 μm. Note that the particle diameters indicated here mean that the organic particles 72 contained in the scratch-resistant layer 7 predominantly consist of organic particles of these particle diameters. Of the organic particles 72 contained in the scratch-resistant layer 7, the proportion of organic particles with these particle diameters is preferably 50% or more, more preferably 80% or more, even more preferably 90% or more, and may even be 100%.

The particle diameter of the organic particles 72 is a value measured on a cross-sectional image of the scratch-resistant layer 7 in the thickness direction observed using a scanning electron microscope. Note that the particle diameter of the organic particles 72 refers to the diameter at which the linear distance connecting the leftmost end of the particle in the direction perpendicular to the thickness direction and the rightmost end of the particle in the direction perpendicular to the thickness direction is the longest, as observed using a scanning electron microscope. The particle diameter of the organic particles 72 is not the average particle diameter.

The shape of the organic particles 72 is not particularly limited, and examples include spherical, fibrous, plate-like, irregular, and scaly shapes, with spherical shapes being preferred.

From the viewpoint of optimally achieving both excellent scratch resistance and excellent moldability, when the scratch-resistant layer 7 contains organic particles 72, the content thereof is preferably at least about 0.01 parts by weight, more preferably at least about 0.1 parts by weight, and even more preferably at least about 0.5 parts by weight, per 100 parts by weight of the resin. From the same viewpoint, the content is preferably no more than about 10.0 parts by weight, more preferably no more than about 5.0 parts by weight, and even more preferably no more than about 3.0 parts by weight. Preferred ranges for the content include approximately 0.01 to 10.0 parts by weight, approximately 0.01 to 5.0 parts by weight, approximately 0.01 to 3.0 parts by weight, approximately 0.1 to 10.0 parts by weight, approximately 0.1 to 5.0 parts by weight, approximately 0.1 to 3.0 parts by weight, approximately 0.5 to 10.0 parts by weight, approximately 0.5 to 5.0 parts by weight, and approximately 0.5 to 3.0 parts by weight.

The average thickness of the scratch-resistant layer 7 is not particularly limited, as long as the combined average thickness of the scratch-resistant layer 7 and the substrate protective layer 6 (described below) is 10 μm or less. However, from the viewpoint of achieving both excellent scratch resistance and excellent formability, it is preferably about 2.5 μm or less, more preferably about 2.0 μm or less, and even more preferably about 1.5 μm or less. From the same viewpoint, the average thickness of the scratch-resistant layer 7 is preferably about 0.3 μm or more, more preferably about 0.5 μm or more. Preferred ranges for the average thickness of the scratch-resistant layer 7 include approximately 0.3 to 2.5 μm, approximately 0.3 to 2.0 μm, approximately 0.3 to 1.5 μm, approximately 0.5 to 2.5 μm, approximately 0.5 to 2.0 μm, and approximately 0.5 to 1.5 μm. The average thickness of the scratch-resistant layer 7 is measured as follows.

<Average film thickness>
The average film thicknesses of the scratch-resistant layer 7 and the substrate protective layer 6 of the laminate constituting the electrical storage device packaging material are measured and calculated as follows. A cross-sectional image is obtained using a scanning electron microscope (SEM) for a cross section in the thickness direction of the laminate constituting the electrical storage device packaging material. Next, for the cross-sectional image, the cross-sectional areas of the scratch-resistant layer 7 and the substrate protective layer 6 are each measured by image analysis. At this time, the horizontal length (length perpendicular to the thickness direction of the laminate) of the measurement area of the cross-sectional area is set to 25.4 μm. Next, the obtained area is divided by the horizontal length (25.4 μm) to calculate the average film thickness (μm) of the scratch-resistant layer 7 and the substrate protective layer 6. When measuring and calculating the total average film thickness of the scratch-resistant layer 7 and the substrate protective layer 6, the cross-sectional areas of the scratch-resistant layer 7 and the substrate protective layer 6 in the same measurement area are measured simultaneously, and the obtained area is divided by the horizontal length of the measurement area (25.4 μm) to calculate the average film thickness (μm) of the scratch-resistant layer 7 and the substrate protective layer 6 combined.

The scratch-resistant layer 7 preferably contains particles with a particle size larger than the average film thickness of the scratch-resistant layer 7. That is, the scratch-resistant layer 7 preferably contains, as at least a portion of its inorganic particles, at least one of inorganic particles with a particle size larger than the average film thickness of the scratch-resistant layer 7 and organic particles with a particle size larger than the average film thickness of the scratch-resistant layer 7. Furthermore, the substrate protective layer 6, described below, preferably contains particles with a particle size larger than the average film thickness of the substrate protective layer 6. That is, the substrate protective layer 6 preferably contains at least one of inorganic particles with a particle size larger than the average film thickness of the substrate protective layer 6 and organic particles with a particle size larger than the average film thickness of the substrate protective layer 6. For each of the scratch-resistant layer 7 and the substrate protective layer 6, particles with a particle size larger than the average film thickness of each layer will be referred to as "large particles" hereinafter. It is more preferable that both the scratch-resistant layer 7 and the substrate protective layer 6 contain large particles. The large particles are preferably inorganic particles 61, 71 or organic particles 62, 72, with organic particles 72 being preferred. That is, when organic particles 62, 72 are contained in at least one of the scratch-resistant layer 7 and the substrate protective layer 6, it is preferable that at least one of the scratch-resistant layer 7 and the substrate protective layer 6 contains organic particles 62, 72 with a particle diameter larger than the average film thickness of the layer. It is preferable that each layer (scratch-resistant layer 7 and substrate protective layer 6) contains, for example, about 30 or more large particles within a 1 mm wide range of each layer. The number of large particles within a 1 mm wide range of each layer is preferably about 50 or more, more preferably about 70 or more. Furthermore, the number of large particles within a 1 mm wide range of each layer is preferably about 500 or less, more preferably about 400 or less, and even more preferably about 200 or less. Furthermore, preferred ranges for the number of large particles within a 1 mm wide range in each layer include approximately 30 to 500, approximately 30 to 400, approximately 30 to 200, approximately 50 to 500, approximately 50 to 400, approximately 50 to 200, approximately 70 to 500, approximately 70 to 400, and approximately 70 to 200. The number of large particles can be obtained by observing cross-sectional images (1 mm wide) of each layer in the thickness direction using a scanning electron microscope.

The particle diameter of these large particles is preferably approximately 1.0 to 5.0 μm.

When the hardness of the large particles and resin in a cross section of the scratch-resistant layer 7 in the thickness direction is measured by nanoindentation in a 23°C environment, it is preferable that the hardness of the large particles be greater than the hardness of the resin. In this disclosure, the method for measuring hardness by nanoindentation is as follows.

<Hardness measured by nanoindentation method in a 23°C environment>
The hardness is measured using a nanoindenter (for example, a "TI950 TriboIndenter" manufactured by HYSITRON) as the device. A Berkovich indenter (for example, TI-0039) is used as the indenter of the nanoindenter. First, in an environment of 50% relative humidity and 23°C, the indenter is applied to the surface to be measured of the electrical storage device exterior material (the surface on which the scratch-resistant layer or base protective layer is exposed, parallel to the thickness direction of each layer) from a direction perpendicular to the thickness direction, and the indenter is pressed from the surface to a load of 50 μN over 10 seconds, held in that state for 5 seconds, and then unloaded over 10 seconds. The average value of N = 5 measurements made at different measurement points is taken as the hardness. The surface into which the indenter is pressed is the exposed cross section of the scratch-resistant layer or base protective layer to be measured, obtained by cutting the electrical storage device exterior material in the thickness direction so as to pass through the center. In addition, when measuring the hardness of the resin of the scratch-resistant layer or the substrate protective layer, the indenter is pressed into the part (resin part) where no particles are present on the surface. When measuring the hardness of the particles of the scratch-resistant layer or the substrate protective layer, the indenter is pressed into the part where particles are present on the surface. Cutting is performed using a commercially available rotary microtome.

The hardness of the large particles, as measured by nanoindentation, is preferably about 400 MPa or more, more preferably about 430 MPa or more. Furthermore, the hardness is preferably about 600 MPa or less. Preferred ranges for the hardness include approximately 400 to 600 MPa and approximately 430 to 600 MPa. Large particles with these hardnesses are preferably large organic particles.

In the scratch-resistant layer 7, the difference between the hardness of the large particles and the hardness of the resin is preferably approximately 100 MPa or more, more preferably approximately 130 MPa or more. Furthermore, this hardness is preferably approximately 300 MPa or less. Preferred ranges for this hardness include approximately 100 to 300 MPa and approximately 130 to 300 MPa. Large particles with these hardnesses are preferably large organic particles.

The resin contained in the scratch-resistant layer 7 is preferably a curable resin. In other words, the scratch-resistant layer 7 is preferably composed of a cured product of a resin composition containing a curable resin and inorganic particles 71.

The curable resin may be either a one-component curing type or a two-component curing type, but is preferably a two-component curing type. Examples of two-component curing resins include two-component curing polyurethane, two-component curing polyester, and two-component curing epoxy resin. Of these, two-component curing polyurethane is preferred.

Examples of two-component curing polyurethanes include polyurethanes 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 a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the base agent and an aromatic or aliphatic polyisocyanate as the curing agent. Furthermore, it is preferable to use a polyester polyol that has hydroxyl groups on the side chain in addition to the terminal hydroxyl groups of the repeating unit as the polyol compound. Examples of curing agents 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), and naphthalene diisocyanate (NDI). Also included are polyfunctional isocyanate-modified compounds of one or more of these diisocyanates. Furthermore, polymers (e.g., trimers) can also be used as polyisocyanate compounds. Examples of such polymers include adducts, biurets, and nurates. Note that an aliphatic isocyanate compound refers to an isocyanate that has an aliphatic group but no aromatic ring, an alicyclic isocyanate compound refers to an isocyanate that has an alicyclic hydrocarbon group, and an aromatic isocyanate compound refers to an isocyanate that has an aromatic ring.

It is preferable that the scratch-resistant layer 7 and the substrate protective layer 6 each contain a different resin. More specifically, it is preferable that the scratch-resistant layer 7 and the substrate protective layer 6 contain different resins, and that these layers have different hardnesses measured by nanoindentation, and it is preferable that the hardness of the resin in the scratch-resistant layer 7 is greater than the hardness of the resin in the substrate protective layer 6.

The hardness of the resin of the scratch-resistant layer 7, as measured by nanoindentation, is preferably approximately 150 MPa or more, and more preferably approximately 170 MPa or more. Furthermore, this hardness is preferably approximately 400 MPa or less, and more preferably approximately 300 MPa or less. Preferred ranges for this hardness include approximately 150 to 400 MPa, approximately 150 to 300 MPa, approximately 170 to 400 MPa, and approximately 170 to 300 MPa.

The difference in hardness between the resin of the scratch-resistant layer 7 and the resin of the substrate protective layer 6 is preferably approximately 100 MPa or more, more preferably approximately 150 MPa or more. Furthermore, this difference is preferably approximately 300 MPa or less, more preferably 250 MPa or less. Preferred ranges for this hardness difference include approximately 100 to 300 MPa, approximately 100 to 250 MPa, approximately 150 to 300 MPa, and approximately 150 to 250 MPa. As mentioned above, it is preferable that the hardness of the resin of the scratch-resistant layer 7 be greater than the hardness of the resin of the substrate protective layer 6.

When the resin composition forming the scratch-resistant layer 7 is a polyurethane containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound, the hardness of the resin measured by nanoindentation can be adjusted, for example, by adjusting the ratio of the base agent to the curing agent.

At least one of the surface and interior of the scratch-resistant layer 7 may further contain additives (additives) such as lubricants, colorants, antiblocking agents, flame retardants, antioxidants, tackifiers, and antistatic agents, as described below, depending on the functionality that the scratch-resistant layer 7 and its surface are to be provided with.

When the scratch-resistant layer 7 contains a colorant, known colorants such as pigments and dyes can be used. Furthermore, a single colorant may be used, or two or more colorants may be mixed together. Specific examples of colorants contained in the scratch-resistant layer 7 include the same as those exemplified in the [Adhesive layer 2] section. Furthermore, the preferred content of the colorant contained in the scratch-resistant layer 7 is also the same as the content described in the [Adhesive layer 2] section.

The method for forming the scratch-resistant layer 7 is not particularly limited, and examples include a method of applying a resin composition that forms the scratch-resistant layer 7. If an additive is added to the scratch-resistant layer 7, a resin mixed with the additive may be applied.

In the present disclosure, from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferable that a lubricant be present on the surface of the scratch-resistant layer 7. The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of amide-based 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, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. 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, and N-stearyl erucic acid amide. Specific examples of methylolamides include methylol stearic acid amide. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipamide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamidoethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearyl isophthalic acid amide. The lubricants may be used alone or in combination of two or more.

When a lubricant is present on the surface of the scratch-resistant layer 7, the amount of the lubricant present is not particularly limited, but is preferably about 3 mg/ ^m2 or more, more preferably about 4 to 15 mg/ ^m2 , and even more preferably about 5 to 14 mg/ ^m2 .

The lubricant present on the surface of the scratch-resistant layer 7 may be a lubricant exuded from the scratch-resistant layer 7, or a lubricant applied to the surface of the scratch-resistant layer 7.

[Base material protective layer 6]
The electrical storage device packaging material 10 of the present disclosure has a substrate protective layer 6 between the scratch-resistant layer 7 and the substrate layer 1 for the purpose of improving the formability of the electrical storage device packaging material 10 including the scratch-resistant layer 7. The substrate protective layer 6 is preferably in contact with the scratch-resistant layer 7 and the substrate layer 1.

Furthermore, as described above, the average combined film thickness of the scratch-resistant layer 7 and the substrate protective layer 6 of the exterior packaging material 10 for an electricity storage device according to the present disclosure is set to 10 μm or less.

The substrate protective layer 6 contains a resin and preferably further contains inorganic particles 61. That is, the substrate protective layer 6 is preferably formed from a resin composition containing a resin and inorganic particles 61.

Examples of inorganic particles 61 include the same as those exemplified for the scratch-resistant layer 7. Among these, barium sulfate is particularly preferred as the inorganic particles 61 contained in the substrate protective layer 6, from the viewpoint of achieving both excellent scratch resistance and excellent formability. The inorganic particles 61 contained in the substrate protective layer 6 may be of one type, or two or more types.

In the substrate protective layer 6, the shape of the inorganic particles 61 is not particularly limited, and examples include spherical, fibrous, plate-like, irregular, and scaly shapes, with spherical shapes being preferred.

In the substrate protective layer 6, the average particle size of the inorganic particles 61 is, for example, approximately 0.5 nm to 5 μm, preferably approximately 0.5 to 3 μm, from the viewpoint of achieving both excellent scratch resistance and excellent formability.

The average particle diameter of the inorganic particles 61 is the median diameter measured using a laser diffraction/scattering particle size distribution measuring device.

From the viewpoint of optimally achieving both excellent scratch resistance and excellent moldability, the content of inorganic particles 61 contained in the substrate protective layer 6 is preferably at least about 0.1 part by weight, more preferably at least about 0.5 part by weight, and even more preferably at least about 1.0 part by weight, per 100 parts by weight of the resin in the substrate protective layer 6. From the same viewpoint, the number of large particles within a 1 mm width of each layer is preferably no more than about 10.0 parts by weight, more preferably no more than about 5.0 parts by weight, and even more preferably no more than about 3.0 parts by weight, per 100 parts by weight of the resin. Furthermore, preferred ranges for the number of large particles within a 1 mm width of each layer include, relative to 100 parts by mass of the resin, approximately 0.1 to 10.0 parts by mass, approximately 0.1 to 5.0 parts by mass, approximately 0.1 to 3.0 parts by mass, approximately 0.5 to 10.0 parts by mass, approximately 0.5 to 5.0 parts by mass, approximately 0.5 to 3.0 parts by mass, approximately 1.0 to 10.0 parts by mass, approximately 1.0 to 5.0 parts by mass, and approximately 1.0 to 3.0 parts by mass.

From the viewpoint of achieving both excellent scratch resistance and excellent formability, it is preferable that the substrate protective layer 6 further contains organic particles 62 in addition to the inorganic particles 61. Examples of organic particles 62 include the same particles as those exemplified in the section on [Scratch-Resistant Layer 7]. The organic particles 62 contained in the substrate protective layer 6 may be of one type, or two or more types.

In the substrate protective layer 6, the particle diameter of the organic particles 62 is preferably approximately 5.0 μm or less, more preferably approximately 3.0 μm or less, and even more preferably approximately 2.0 μm or less, from the viewpoint of achieving both excellent scratch resistance and excellent formability. From the same viewpoint, the particle diameter of the organic particles 62 is preferably approximately 0.3 μm or more, more preferably approximately 0.5 μm or more. Preferred particle diameter ranges for the organic particles 62 include approximately 0.3 to 5.0 μm, approximately 0.3 to 3.0 μm, approximately 0.3 to 2.0 μm, approximately 0.5 to 5.0 μm, approximately 0.5 to 3.0 μm, and approximately 0.5 to 2.0 μm. The particle diameters indicated here mean that the organic particles 62 contained in the substrate protective layer 6 predominantly consist of organic particles with these particle diameters. Of the organic particles 62 contained in the substrate protective layer 6, the proportion of organic particles with these particle diameters is preferably 50% or more, more preferably 80% or more, even more preferably 90% or more, and may even be 100%.

The particle diameter of the organic particles 62 is a value measured on a cross-sectional image of the substrate protective layer 6 in the thickness direction observed using a scanning electron microscope. The particle diameter of the organic particles 62 refers to the diameter at which the linear distance connecting the leftmost end of the particle in the direction perpendicular to the thickness direction and the rightmost end of the particle in the direction perpendicular to the thickness direction is the longest, as observed using a scanning electron microscope. The particle diameter of the organic particles 62 is not the average particle diameter.

The shape of the organic particles 62 is not particularly limited, and examples include spherical, fibrous, plate-like, irregular, and scaly shapes, with spherical being preferred.

From the viewpoint of optimally achieving both excellent scratch resistance and excellent moldability, when organic particles 62 are included in the substrate protective layer 6, the content thereof is preferably at least about 0.01 part by mass, more preferably at least about 0.1 part by mass, and even more preferably at least about 0.5 part by mass, per 100 parts by mass of the resin. From the same viewpoint, the content is preferably no more than about 10.0 parts by mass, more preferably no more than about 5.0 parts by mass, and even more preferably no more than about 3.0 parts by mass. Preferred ranges for the content include approximately 0.01 to 10.0 parts by mass, approximately 0.01 to 5.0 parts by mass, approximately 0.01 to 3.0 parts by mass, approximately 0.1 to 10.0 parts by mass, approximately 0.1 to 5.0 parts by mass, approximately 0.1 to 3.0 parts by mass, approximately 0.5 to 10.0 parts by mass, approximately 0.5 to 5.0 parts by mass, and approximately 0.5 to 3.0 parts by mass.

The average thickness of the substrate protective layer 6 is not particularly limited, as long as the combined average thickness of the scratch-resistant layer 7 and the substrate protective layer 6 is 10 μm or less. However, from the viewpoint of achieving both excellent scratch resistance and excellent formability, it is preferably about 2.0 μm or less, and more preferably about 1.5 μm or less. From the same viewpoint, the average thickness of the substrate protective layer 6 is preferably about 0.1 μm or more, and more preferably about 0.3 μm or more. Preferred ranges for the average thickness of the substrate protective layer 6 include approximately 0.1 to 2.0 μm, approximately 0.1 to 1.5 μm, approximately 0.3 to 2.0 μm, and approximately 0.3 to 1.5 μm. The method for measuring the average thickness of the substrate protective layer 6 is as described above.

As described above, at least one of the scratch-resistant layer 7 and the substrate protective layer 6 preferably contains particles with a particle diameter larger than the average film thickness of that layer, and it is more preferable that both the scratch-resistant layer 7 and the substrate protective layer 6 contain such large particles. The large particles are preferably either the inorganic particles 61, 71 or the organic particles 62, 72, and are preferably organic particles 62. In other words, when at least one of the scratch-resistant layer 7 and the substrate protective layer 6 contains organic particles 62, 72, it is preferable that at least one of the scratch-resistant layer 7 and the substrate protective layer 6 contains organic particles 62, 72 with a particle diameter larger than the average film thickness of that layer.

As mentioned above, the particle size of the large particles is preferably approximately 1.0 to 5.0 μm.

When the hardness of the large particles and resin in a cross section in the thickness direction of the substrate protective layer 6 is measured by nanoindentation in a 23°C environment, it is preferable that the hardness of the large particles be greater than the hardness of the resin in the substrate protective layer 6. In this disclosure, the method for measuring hardness by nanoindentation is as described above.

The hardness of the large particles in the substrate protective layer 6, as measured by nanoindentation, is preferably approximately 400 MPa or more, and more preferably approximately 430 MPa or more. Furthermore, this hardness is preferably approximately 600 MPa or less. Preferred ranges for this hardness include approximately 400 to 600 MPa and approximately 430 to 600 MPa. Large particles with these hardnesses are preferably large organic particles.

The resin contained in the substrate protective layer 6 is preferably a curable resin. In other words, it is more preferable that the substrate protective layer 6 be composed of a cured product of a resin composition containing a curable resin.

In the substrate protective layer 6, the curable resin may be either a one-component curing type or a two-component curing type, but a two-component curing type is preferred. Examples of two-component curing resins include two-component curing polyurethane, two-component curing polyester, and two-component curing epoxy resin. Of these, two-component curing polyurethane is preferred.

Examples of two-component curing polyurethane include the same as those listed above under [Scratch-resistant layer 7].

The hardness of the resin of the substrate protective layer 6, as measured by nanoindentation, is preferably about 150 MPa or less, more preferably about 100 MPa or less, and even more preferably about 50 MPa or less. Furthermore, the hardness is preferably about 5 MPa or more, more preferably about 10 MPa or more. Preferred ranges for the hardness include approximately 5 to 150 MPa, approximately 5 to 100 MPa, approximately 5 to 50 MPa, approximately 10 to 150 MPa, approximately 10 to 100 MPa, and approximately 10 to 50 MPa.

When the resin composition forming the substrate protective layer 6 is a polyurethane containing a base resin containing a polyol compound and a curing agent containing an isocyanate compound, the hardness of the resin measured by nanoindentation can be adjusted, for example, by adjusting the ratio of the base resin to the curing agent.

The substrate protective layer 6 may further contain additives such as colorants, antiblocking agents, flame retardants, antioxidants, tackifiers, and antistatic agents, as described below, depending on the functionality that the substrate protective layer 6 is to have.

When the substrate protective layer 6 contains a colorant, known colorants such as pigments and dyes can be used. Furthermore, a single colorant may be used, or two or more colorants may be mixed. Specific examples of colorants contained in the substrate protective layer 6 include the same as those exemplified in the [Adhesive Layer 2] section. Furthermore, the preferred content of the colorant contained in the substrate protective layer 6 is also the same as the content described in the [Adhesive Layer 2] section.

The method for forming the substrate protective layer 6 is not particularly limited, and examples include a method of applying a resin composition that forms the substrate protective layer 6. If an additive is blended into the substrate protective layer 6, a resin mixed with the additive may be applied.

[Base material layer 1]
In the present disclosure, the substrate layer 1 is a layer provided for the purpose of allowing the substrate layer 1 to function as a substrate of the electrical storage device packaging material 10. The substrate layer 1 is located between the substrate protective layer 6 and the barrier layer 3 of the electrical storage device packaging material 10.

There are no particular restrictions on the material from which the substrate layer 1 is made, as long as it functions as a substrate, i.e., has at least insulating properties. The substrate layer 1 can be made using, for example, a resin, which may contain additives as described below.

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

Examples of resins that form the base layer 1 include polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. The resin that forms the base layer 1 may also be a copolymer of these resins, or a modified version of the copolymer. It may also be a mixture of these resins.

Of these, polyester and polyamide are preferred as resins for forming the base layer 1.

Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Copolymer polyesters include those in which ethylene terephthalate is the main repeating unit. Specific examples include copolymer polyesters in which ethylene terephthalate is the main repeating unit polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate/isophthalate)), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate), and polyethylene (terephthalate/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; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (where I represents isophthalic acid and T represents terephthalic acid), which contain structural units derived from terephthalic acid and/or isophthalic acid; aromatic polyamides such as polyamide MXD6 (polymetaxylylene adipamide); alicyclic polyamides such as polyamide PACM6 (polybis(4-aminocyclohexyl)methane adipamide); polyamides copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and other polyamide copolymers. These polyamides may be used alone or in combination of two or more.

The substrate layer 1 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, preferably 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, and even more preferably at least one of a biaxially oriented polyethylene terephthalate film, a biaxially oriented polybutylene terephthalate film, a biaxially oriented nylon film, and a biaxially oriented polypropylene film.

The base layer 1 may be a single layer, or may be composed of two or more layers. When the base layer 1 is composed of two or more layers, the base layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or a laminate of resin films formed by co-extrusion of resins into two or more layers. Furthermore, a laminate of resin films formed by co-extrusion of resins into two or more layers may be used as the base layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base layer 1.

Specific examples of laminates of two or more resin films in the base layer 1 include a laminate of polyester film and nylon film, a laminate of two or more nylon film layers, and a laminate of two or more polyester film layers. Preferably, they are a laminate of stretched nylon film and stretched polyester film, a laminate of two or more stretched nylon film layers, or a laminate of two or more stretched polyester film layers. For example, when the base layer 1 is a laminate of two resin films, a laminate of polyester resin film and polyester resin film, a laminate of polyamide resin film and polyamide resin film, or a laminate of polyester resin film and polyamide resin film is preferred. A laminate of polyethylene terephthalate film and polyethylene terephthalate film, a laminate of nylon film and nylon film, or a laminate of polyethylene terephthalate film and nylon film is more preferred. Furthermore, because polyester resins are less likely to discolor when electrolyte solution adheres to their surface, it is preferable that the polyester resin film be the outermost layer of the base layer 1 when the base layer 1 is a laminate of two or more resin films.

When the base layer 1 is a laminate of two or more resin film layers, the two or more resin film layers may be laminated via an adhesive. Examples of preferred adhesives include those similar to those exemplified for adhesive layer 2, described below. The method for laminating two or more resin film layers is not particularly limited, and known methods can be used, such as dry lamination, sandwich lamination, extrusion lamination, and thermal lamination, with dry lamination being preferred. When laminating using the dry lamination method, a polyurethane adhesive is preferably used as the adhesive. In this case, the adhesive thickness can be, for example, approximately 2 to 5 μm. Alternatively, an anchor coat layer can be formed on the resin film before lamination. Examples of the anchor coat layer include those similar to those exemplified for adhesive layer 2, described below. In this case, the anchor coat layer thickness can be, for example, approximately 0.01 to 1.0 μm.

Additives such as flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present on at least one of the surface and interior of the base layer 1. A single type of additive may be used, or two or more types may be mixed together.

The thickness of the substrate layer 1 is not particularly limited as long as it functions as a substrate, but examples include approximately 3 to 50 μm, and preferably approximately 10 to 35 μm. When the substrate layer 1 is a laminate of two or more resin film layers, the thickness of each resin film constituting each layer is preferably approximately 2 to 25 μm.

[Adhesive layer 2]
In the packaging material for an electricity storage device of the present disclosure, the adhesive layer 2 is a layer that is provided between the base layer 1 and the barrier layer 3 as needed for the purpose of increasing the adhesion between them.

The adhesive layer 2 is formed from an adhesive capable of bonding the base layer 1 and the barrier layer 3. There are no limitations on the adhesive used to form the adhesive layer 2, and it may be any of a chemical reaction type, a solvent evaporation type, a hot melt type, a thermocompression type, etc. It may also 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. The adhesive layer 2 may be a single layer or multiple layers.

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

Examples of polyurethane adhesives include those 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 a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the base agent and an aromatic or aliphatic polyisocyanate as the curing agent. Furthermore, it is preferable to use a polyester polyol that has hydroxyl groups on the side chain in addition to the terminal hydroxyl groups of the repeating unit as the polyol compound. Forming the adhesive layer 2 from a polyurethane adhesive provides the electrical storage device exterior material with excellent electrolyte resistance, preventing peeling of the base layer 1 even when electrolyte adheres to the side surface.

In addition, the adhesive layer 2 may contain other components as long as they do not impair adhesion, such as colorants, thermoplastic elastomers, tackifiers, and fillers. By including a colorant in the adhesive layer 2, the electrical storage device packaging material can be colored. Known colorants such as pigments and dyes can be used. A single colorant may be used, or two or more colorants may be mixed together.

There are no particular restrictions on the type of pigment, so long as it does not impair the adhesive properties of the adhesive layer 2. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments. Examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments. Other examples include finely powdered mica and fish scale foil.

Among colorants, carbon black is preferred, for example, to give the exterior material for an electrical storage device a black appearance.

The average particle size of the pigment is not particularly limited, but may be, for example, approximately 0.05 to 5 μm, and preferably approximately 0.08 to 2 μm. The average particle size of the pigment is the median diameter measured using a laser diffraction/scattering particle size distribution analyzer.

The pigment content in the adhesive layer 2 is not particularly limited as long as it colors the electrical storage device exterior material, but may be, for example, approximately 5 to 60% by mass, and preferably 10 to 40% by mass.

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

[Colored layer]
The colored layer is a layer (not shown) that is provided as needed between the base material layer 1 and the barrier layer 3. When the adhesive layer 2 is provided, a colored layer 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. Alternatively, a colored layer may be provided on the outside of the base material layer 1. By providing a colored layer, the packaging material for an electricity storage device can be colored.

The colored layer can be formed, for example, by applying ink containing a colorant to the surface of the base layer 1 or the surface of the barrier layer 3. Known colorants such as pigments and dyes can be used as colorants. Furthermore, a single type of colorant may be used, or two or more types may be mixed together.

Specific examples of colorants contained in the colored layer include the same as those exemplified in the [Adhesive Layer 2] section.

[Barrier layer 3]
In the packaging material for an electricity storage device, the barrier layer 3 is a layer that at least prevents the penetration of moisture.

Examples of the barrier layer 3 include metal foils, vapor-deposited films, and resin layers with barrier properties. Vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Resin layers include fluorine-containing resins such as polyvinylidene chloride, polymers based on chlorotrifluoroethylene (CTFE), polymers based on tetrafluoroethylene (TFE), polymers containing fluoroalkyl groups, and polymers based on fluoroalkyl units, as well as ethylene-vinyl alcohol copolymers. Examples of the barrier layer 3 also include resin films comprising at least one of these vapor-deposited films and resin layers. The barrier layer 3 may comprise multiple layers. The barrier layer 3 preferably includes a layer composed of a metal material. Specific examples of metal materials that make up the barrier layer 3 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, the barrier layer 3 preferably includes at least one of aluminum alloy foil and stainless steel foil.

From the viewpoint of improving the formability of the electrical storage device exterior material, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of further improving formability, it is preferably an iron-containing aluminum alloy foil. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. By having an iron content of 0.1% by mass or more, an electrical storage device exterior material with better formability can be obtained. By having an iron content of 9.0% by mass or less, an electrical storage device exterior material with better flexibility can be obtained. Examples of soft aluminum alloy foils include aluminum alloy foils having compositions specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may also be added as needed. Softening can be achieved by annealing or other methods.

Furthermore, examples of stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation-hardened stainless steel foils. Furthermore, from the perspective of providing an exterior material for an electricity storage device with excellent formability, it is preferable that the stainless steel foil be made of austenitic stainless steel.

Specific examples of austenitic stainless steels that make up the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

In the case of a metal foil, the thickness of the barrier layer 3 should at least function as a barrier layer to prevent moisture penetration, and can be, for example, approximately 9 to 200 μm. The thickness of the barrier layer 3 is preferably approximately 85 μm or less, more preferably approximately 50 μm or less, even more preferably approximately 40 μm or less, and particularly preferably approximately 35 μm or less. The thickness of the barrier layer 3 is preferably approximately 10 μm or more, even more preferably approximately 20 μm or more, and more preferably approximately 25 μm or more. Preferred thickness ranges include approximately 10 to 85 μm, approximately 10 to 50 μm, approximately 10 to 40 μm, approximately 10 to 35 μm, approximately 20 to 85 μm, approximately 20 to 50 μm, approximately 20 to 40 μm, approximately 20 to 35 μm, approximately 25 to 85 μm, approximately 25 to 50 μm, approximately 25 to 40 μm, and approximately 25 to 35 μm. When the barrier layer 3 is made of aluminum alloy foil, the above-mentioned range is particularly preferred. Furthermore, 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, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred thickness ranges for the stainless steel foil include approximately 10 to 60 μm, approximately 10 to 50 μm, approximately 10 to 40 μm, approximately 10 to 30 μm, approximately 10 to 25 μm, approximately 15 to 60 μm, approximately 15 to 50 μm, approximately 15 to 40 μm, approximately 15 to 30 μm, and approximately 15 to 25 μm.

Furthermore, when the barrier layer 3 is a metal foil, it is preferable that at least the surface opposite the substrate layer be provided with a corrosion-resistant coating to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion-resistant coating on both sides. Here, a corrosion-resistant coating refers to a thin film formed on the surface of the barrier layer that is corrosion-resistant, and is obtained by, 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. A single type of treatment may be used to form the corrosion-resistant coating, or two or more types may be combined. Furthermore, multiple layers may be formed, rather than a single layer. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment dissolve the metal foil surface with a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may also be included in the definition of chemical conversion treatment. Furthermore, when the barrier layer 3 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 3.

The corrosion-resistant coating prevents delamination between the barrier layer (e.g., aluminum alloy foil) and the substrate layer during molding of the electrical storage device exterior material, prevents dissolution and corrosion of the barrier layer surface due to hydrogen fluoride produced by the reaction between the electrolyte and water, and particularly prevents dissolution and corrosion of aluminum oxide present on the barrier layer surface when the barrier layer is aluminum alloy foil, and also improves the adhesion (wettability) of the barrier layer surface, preventing delamination between the substrate layer and barrier layer during heat sealing and molding.

Various corrosion-resistant coatings formed by chemical conversion treatments are known, including those containing at least one of phosphates, chromates, fluorides, triazine thiol compounds, and rare earth oxides. Examples of chemical conversion treatments using phosphates and chromates include chromate chromate treatment, phosphate chromate treatment, phosphate-chromate treatment, and chromate treatment. Chromium compounds used in these treatments include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromate acetylacetate, chromium chloride, and potassium chromium sulfate. Phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid. Chromate treatments include etching chromate treatment, electrolytic chromate treatment, and paint-on chromate treatment, with paint-on chromate treatment being preferred. This paint-type chromate treatment involves first degreasing at least the inner surface of a barrier layer (e.g., an aluminum alloy foil) using a well-known method such as alkali immersion, electrolytic cleaning, acid pickling, electrolytic pickling, or acid activation, and then coating the degreased surface with a treatment solution containing, as its main component, a metal phosphate such as chromium (Cr) phosphate, titanium (Ti) phosphate, zirconium (Zr) phosphate, or zinc (Zn) phosphate, or a mixture of these metal salts, or a treatment solution containing, as its main component, a nonmetallic phosphate and a mixture of these nonmetallic salts, or a mixture of these with a synthetic resin, by a well-known coating method such as roll coating, gravure printing, or immersion, followed by drying. The treatment solution can be, for example, water, alcoholic solvents, hydrocarbon solvents, ketone solvents, ester solvents, or ether solvents, with water being preferred. The resin component used here may include polymers such as phenolic resins and acrylic resins, and examples thereof include chromate treatment using an aminated phenolic polymer having repeating units represented by the following general formulas (1) to (4). The aminated phenolic polymer may contain one repeating unit represented by the following general formulas (1) to (4) alone, or any combination of two or more repeating units. The acrylic resin is preferably polyacrylic acid, an acrylic acid-methacrylic acid ester copolymer, an acrylic acid-maleic acid copolymer, an acrylic acid-styrene copolymer, or a derivative thereof, such as a sodium salt, an ammonium salt, or an amine salt. Derivatives of polyacrylic acid, such as the ammonium salt, sodium salt, or amine salt of polyacrylic acid, are particularly preferred. In this disclosure, polyacrylic acid refers to a polymer of acrylic acid. The acrylic resin is also preferably a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride, and preferably an ammonium salt, a sodium salt, or an amine salt of a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride. Only one type of acrylic resin may be used, or two or more types may be mixed together.

In 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. ^R1 and ^R2 , which may be the same or different, represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. In general formulas (1) to (4), examples of the alkyl group represented by X, ^R1 , and ^R2 include linear or branched alkyl groups having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. Examples of the hydroxyalkyl group represented by X, ^R1 , and ^R2 include linear or branched alkyl groups having 1 to 4 carbon atoms and substituted with one hydroxy group, such as a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, and a 4-hydroxybutyl group. In general formulas (1) to (4), the alkyl groups and hydroxyalkyl groups represented by X, ^R1 , and ^R2 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, for example, about 500 to 1,000,000, and more preferably about 1,000 to 20,000. The aminated phenol polymer can be produced, for example, by polycondensing a phenol compound or a naphthol compound with formaldehyde to produce a polymer comprising repeating units represented by general formula ( ₁ ) or ^{(3), and then introducing a functional group (—CH2NR1R2) into the resulting polymer using formaldehyde and an amine (R1R2NH ) . The} aminated phenol polymer may be used alone or in combination of two or more types.

Other examples of corrosion-resistant coatings include thin films formed by a coating-type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of rare earth element oxide sol, anionic polymer, and cationic polymer is applied. The coating agent may further contain phosphoric acid or phosphate salts, and a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol contains rare earth element oxide fine particles (e.g., 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 for improved adhesion. The rare earth element oxides contained in the corrosion-resistant coating can be used alone or in combination of two or more. Liquid dispersion media for the rare earth element oxide sol can include various solvents, such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents, with water being preferred. Preferred examples of cationic polymers include polyethyleneimine, ionic polymer complexes consisting of polyethyleneimine and a polymer having a carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is graft-polymerized onto an acrylic backbone, polyallylamine or its derivatives, and aminated phenols. Preferred anionic polymers are poly(meth)acrylic acid or its salts, or copolymers primarily composed of (meth)acrylic acid or its salts. The crosslinking agent is preferably at least one selected from the group consisting of compounds having a functional group selected from isocyanate, glycidyl, carboxyl, and oxazoline groups, and silane coupling agents. The phosphoric acid or phosphoric acid salt is preferably condensed phosphoric acid or a condensed phosphate salt.

One example of a corrosion-resistant coating is one formed by applying a solution of fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, or barium sulfate dispersed in phosphoric acid to the surface of the barrier layer and then baking it at 150°C or higher.

If necessary, the corrosion-resistant coating may have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated. Examples of cationic polymers and anionic polymers include those described above.

The composition of the corrosion-resistant coating 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. For example, when a coating type chromate treatment is performed, the amount of the chromate compound is, for example, about 0.5 to 50 mg, preferably 1 mg, in terms of chromium, per 1 m ² of the surface of the barrier layer 3.
It is desirable that the content of 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 content of the aminated phenol polymer is, for example, about 1.0 to 200 mg, preferably about 5.0 to 150 mg.

The thickness of the corrosion-resistant coating is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 nm to 100 nm, and even more preferably about 1 nm to 50 nm, from the viewpoint of the cohesive strength of the coating and the adhesive strength with the barrier layer and the thermally adhesive resin layer. The thickness of the corrosion-resistant coating can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy. Analysis of the composition of the corrosion-resistant coating using time-of-flight secondary ion mass spectrometry can reveal, for example, secondary ions consisting of Ce, P, and O (e.g., Ce ₂ PO ₄ ⁺ , C
Peaks derived from secondary ions composed of Cr, P, and O (for example, at least one of CrPO 2 + , CrPO ₄ ⁻ , etc.) and secondary ions composed of Cr, P, and O (for example, at least one of CrPO ₂ ⁺ , CrPO ₄ ^{− ,} etc.) are detected.

Chemical conversion treatment is performed by applying a solution containing the compound used to form the corrosion-resistant coating to the surface of the barrier layer using methods such as bar coating, roll coating, gravure coating, or immersion, and then heating the barrier layer to a temperature of approximately 70 to 200°C. Furthermore, before applying chemical conversion treatment to the barrier layer, the barrier layer may be subjected to a degreasing treatment using methods such as alkaline immersion, electrolytic cleaning, acid cleaning, or electrolytic acid cleaning. Performing such a degreasing treatment allows for more efficient chemical conversion treatment of the barrier layer surface. Furthermore, using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid not only degreases the metal foil but also forms a passive metal fluoride. In such cases, it is possible to perform only the degreasing treatment.

[Thermofusible resin layer 4]
In the exterior packaging material for an electricity storage device of the present disclosure, the heat-sealable resin layer 4 corresponds to the innermost layer and is a layer (sealant layer) that functions to seal the electricity storage device elements by heat-sealing the heat-sealable resin layers to each other when assembling the electricity storage device.

The resin constituting the heat-sealable resin layer 4 is not particularly limited as long as it is heat-sealable, but resins containing a polyolefin skeleton, such as polyolefins and acid-modified polyolefins, are preferred. The polyolefin skeleton of the resin constituting the heat-sealable resin layer 4 can be determined by, for example, infrared spectroscopy or gas chromatography-mass spectrometry. Furthermore, when the resin constituting the heat-sealable resin layer 4 is analyzed by infrared spectroscopy, peaks derived from maleic anhydride are preferably detected. For example, when measuring maleic anhydride-modified polyolefin by infrared spectroscopy, peaks derived from maleic anhydride are detected near wavenumbers 1760 cm ⁻¹ and 1780 cm ⁻¹ . When the heat-sealable resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, peaks derived from maleic anhydride are detected by infrared spectroscopy. However, if the degree of acid modification is low, the peaks may be small and not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

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

The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers. Examples of olefins that constitute the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers that constitute the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkenes are preferred, and norbornene is even more preferred.

Acid-modified polyolefins are polymers modified by block or graft polymerization of polyolefins with an acid component. Examples of acid-modified polyolefins include the polyolefins listed above, copolymers of the polyolefins with polar molecules such as acrylic acid or methacrylic acid, and cross-linked polyolefins. Examples of acid components used for acid modification include carboxylic acids or anhydrides such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

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

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

The heat-sealable resin layer 4 may be formed from a single type of resin, or may be formed from a blend polymer of two or more types of resin. Furthermore, the heat-sealable resin layer 4 may be formed from only one layer, or may be formed from two or more layers of the same or different resins.

The heat-sealable resin layer 4 may also contain a lubricant, if necessary. When the heat-sealable resin layer 4 contains a lubricant, the formability of the electrical storage device packaging material can be improved. There are no particular restrictions on the lubricant, and any known lubricant can be used. The lubricant may be used alone or in combination of two or more types.

The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of lubricants include those exemplified for scratch-resistant layer 7. 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, the amount thereof is not particularly limited, but from the viewpoint of improving the formability of the exterior material for an electricity storage device, it is preferably about 10 to 50 mg/ ^m2 , and more preferably about 15 to 40 mg/ ^m2 .

The lubricant present on the surface of the heat-sealable resin layer 4 may be a lubricant exuded from the resin that makes up the heat-sealable resin layer 4, or a lubricant applied to the surface of the heat-sealable resin layer 4.

The thickness of the heat-sealable resin layer 4 is not particularly limited as long as it functions to heat-seal the heat-sealable resin layers together and seal the electricity storage device element, but examples include approximately 100 μm or less, preferably approximately 85 μm or less, and more preferably approximately 15 to 85 μm. For example, if the thickness of the adhesive layer 5 described below is 10 μm or greater, the thickness of the heat-sealable resin layer 4 is preferably approximately 85 μm or less, more preferably approximately 15 to 45 μm. For example, if the thickness of the adhesive layer 5 described below is less than 10 μm or if the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably approximately 20 μm or greater, more preferably approximately 35 to 85 μm.

[Adhesive layer 5]
In the packaging material for an electricity storage device of the present disclosure, the adhesive layer 5 is a layer that is provided as needed between the barrier layer 3 (or acid-resistant film) and the heat-sealable resin layer 4 in order to firmly bond them together.

The adhesive layer 5 is formed from a resin capable of bonding the barrier layer 3 and the heat-sealable resin layer 4. Examples of resins that can be used to form the adhesive layer 5 include the same adhesives as those exemplified for the adhesive layer 2. Furthermore, from the perspective of firmly bonding the adhesive layer 5 and the heat-sealable resin layer 4, the resin used to form the adhesive layer 5 preferably contains a polyolefin skeleton, such as the polyolefins and acid-modified polyolefins exemplified for the heat-sealable resin layer 4. On the other hand, from the perspective of firmly bonding the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 preferably contains an acid-modified polyolefin. Examples of acid-modified components include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, as well as their anhydrides, acrylic acid, and methacrylic acid. However, maleic anhydride is most preferred in terms of ease of modification and versatility. Furthermore, from the perspective of the heat resistance of the electrical storage device packaging material, the olefin component is preferably a polypropylene-based resin, and the adhesive layer 5 most preferably contains maleic anhydride-modified polypropylene.

The inclusion of a polyolefin skeleton in the resin constituting the adhesive layer 5 can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like; the analysis method is not particularly limited. Furthermore, the inclusion of an acid-modified polyolefin in the resin constituting the adhesive layer 5 can be determined, for example, by measuring a maleic anhydride-modified polyolefin by infrared spectroscopy, whereby peaks derived from maleic anhydride are detected at wavenumbers of approximately 1760 ^cm and 1780 ^cm . However, if the degree of acid modification is low, the peaks may be small and not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

Furthermore, from the perspective of ensuring durability, such as heat resistance and resistance to contents, of the electrical storage device exterior packaging material, and ensuring formability while reducing the thickness, it is more preferable that the adhesive layer 5 be a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of acid-modified polyolefins include those listed above.

The adhesive layer 5 is preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one compound 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. It is particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one compound selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. The adhesive layer 5 also preferably contains at least one compound selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably polyurethane and epoxy resin. Preferred polyesters include, for example, ester resins formed by the reaction of epoxy groups with maleic anhydride groups, and amide ester resins formed by the reaction of oxazoline groups with maleic anhydride groups. If unreacted curing agents such as compounds having an isocyanate group, compounds having an oxazoline group, or epoxy resins remain in the adhesive layer 5, the presence of the unreacted materials can be confirmed by a method selected from the group consisting of infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

In order to further enhance the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocycle, a C=N bond, and a C-O-C bond. Examples of curing agents having a heterocycle include curing agents having an oxazoline group and curing agents having an epoxy group. Examples of curing agents having a C=N bond include curing agents having an oxazoline group and curing agents having an isocyanate group. Examples of curing agents having a C-O-C bond include curing agents having an oxazoline group and curing agents having an epoxy group. Whether the adhesive layer 5 is a cured product of a resin composition containing such a curing agent can be confirmed 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), or other methods.

The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively enhancing adhesion between the barrier layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferable. The polyfunctional isocyanate compound is not particularly limited as long as it has 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 polymerized versions of these. Examples of polymers include dimeric uretdione, trimer nurate, biuret, and adducts obtained by addition to polyhydric alcohols (e.g., trimethylolpropane). Furthermore, MDI can also be used in the form of a polymer (polymeric MDI) produced as an oligomer.

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 more preferably in the range of 0.5 to 40% by mass, of the resin composition that constitutes the adhesive layer 5. This effectively improves the adhesion between the barrier layer 3 and the adhesive layer 5.

The compound having an oxazoline group is not particularly limited as long as it has 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. Commercially available products include 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 mass %, and more preferably in the range of 0.5 to 40 mass %, of the resin composition that constitutes the adhesive layer 5. This effectively improves the adhesion between the barrier layer 3 and the adhesive layer 5.

An example of a compound having an epoxy group is an epoxy resin. There are no particular restrictions on the epoxy resin, so long as it is a resin capable of forming a crosslinked structure via the epoxy groups present in the molecule, and known epoxy resins can be used. The weight-average molecular weight of the epoxy resin is preferably approximately 50 to 2,000, more preferably approximately 100 to 1,000, and even more preferably approximately 200 to 800. In the first 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 epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F glycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether. Epoxy resins may be used alone or in combination of two or more.

The proportion of epoxy resin in adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and more preferably in the range of 0.5 to 40% by mass, of the resin composition that makes up adhesive layer 5. This effectively improves the adhesion between barrier layer 3 and adhesive layer 5.

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 a two-component curing polyurethane.

The proportion of polyurethane in adhesive layer 5 is preferably in the range of 0.1 to 50 mass % of the resin composition constituting adhesive layer 5, and more preferably in the range of 0.5 to 40 mass %. This effectively improves adhesion between barrier layer 3 and adhesive layer 5 in an atmosphere containing components that induce corrosion of the barrier layer, such as electrolyte solution.

When 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 the base resin, 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 adhesive layer 5 may contain a modifier having a carbodiimide group.

The thickness of adhesive layer 5 is preferably approximately 50 μm or less, approximately 40 μm or less, approximately 30 μm or less, approximately 20 μm or less, or approximately 5 μm or less. Furthermore, the thickness of adhesive layer 5 is preferably approximately 0.1 μm or more, or approximately 0.5 μm or more. Examples of thickness ranges include approximately 0.1 to 50 μm, approximately 0.1 to 40 μm, approximately 0.1 to 30 μm, approximately 0.1 to 20 μm, approximately 0.1 to 5 μm, approximately 0.5 to 50 μm, approximately 0.5 to 40 μm, approximately 0.5 to 30 μm, approximately 0.5 to 20 μm, and approximately 0.5 to 5 μm. More specifically, for adhesives such as those exemplified for adhesive layer 2, or a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably approximately 1 to 10 μm, and more preferably approximately 1 to 5 μm. Furthermore, when using a resin exemplified for the heat-sealable resin layer 4, the thickness is preferably about 2 to 50 μm, and more preferably about 10 to 40 μm. When the adhesive layer 5 is an adhesive exemplified for the adhesive layer 2, or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed, for example, by applying the resin composition and curing it by heating or the like. When using a resin exemplified for the heat-sealable resin layer 4, the heat-sealable resin layer 4 and the adhesive layer 5 can be formed, for example, by extrusion molding.

3. Manufacturing Method of Electricity Storage Device Exterior Material The manufacturing method of the electricity storage device exterior material is not particularly limited as long as it can obtain a laminate in which each layer included in the electricity storage device exterior material of the present disclosure is laminated, and examples include a method including a step of obtaining a laminate in which, from the outside, at least a scratch-resistant layer 7, a substrate protective layer 6, a substrate layer 1, a barrier layer 3, and a heat-sealable resin layer 4 are laminated. Specifically, the manufacturing method of the electricity storage device exterior material of the present disclosure includes a step of obtaining a laminate by laminating at least the scratch-resistant layer, the substrate protective layer, the substrate layer, the barrier layer, and the heat-sealable resin layer in this order, wherein the scratch-resistant layer contains inorganic particles and a resin, and the average film thickness of the scratch-resistant layer and the substrate protective layer combined is 10 μm or less.

An example of a manufacturing method for an exterior material for an electricity storage device according to the present disclosure is as follows. First, a laminate (hereinafter sometimes referred to as "laminate A") is formed in which a substrate layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order. Specifically, laminate A can be formed by a dry lamination method in which the adhesive used to form adhesive layer 2 is applied to substrate layer 1 or, if necessary, to barrier layer 3 whose surface has been chemically treated, by a coating method such as gravure coating or roll coating, and then dried. After that, the barrier layer 3 or substrate layer 1 is laminated, and the adhesive layer 2 is cured.

Next, a heat-sealable resin layer 4 is laminated on the barrier layer 3 of the laminate A. When the heat-sealable resin layer 4 is laminated directly on the barrier layer 3, the heat-sealable resin layer 4 may be laminated on the barrier layer 3 of the laminate A by a method such as thermal lamination or extrusion lamination. Furthermore, when an adhesive layer 5 is provided between the barrier layer 3 and the heat-sealable resin layer 4, for example, (1) a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 by extruding them onto the barrier layer 3 of the laminate A (co-extrusion lamination, tandem lamination), (2) a method of separately forming a laminate in which the adhesive layer 5 and the heat-sealable resin layer 4 are laminated, and then laminating this on the barrier layer 3 of the laminate A by a thermal lamination, or a method of 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-sealable resin layer 4 by a thermal lamination, (3) a method (sandwich lamination method) in which a molten adhesive layer 5 is poured between the barrier layer 3 of the laminate A and a heat-sealable resin layer 4 that has been pre-formed into a sheet, and the laminate A and the heat-sealable resin layer 4 are bonded together via the adhesive layer 5; (4) a method in which an adhesive for forming the adhesive layer 5 is solution-coated onto the barrier layer 3 of the laminate A, followed by drying or baking, and then the heat-sealable resin layer 4 that has been pre-formed into a sheet is laminated onto this adhesive layer 5.

Next, the substrate protective layer 6 and the scratch-resistant layer 7 are sequentially laminated on the surface of the substrate layer 1 opposite the barrier layer 3. The substrate protective layer 6 and the scratch-resistant layer 7 can be formed, for example, by applying the above-mentioned resin compositions for forming the substrate protective layer 6 and the scratch-resistant layer 7 to the surface of the substrate layer 1 and curing them. There are no particular restrictions on the order of the step of laminating the barrier layer 3 on the surface of the substrate layer 1 and the step of laminating the substrate protective layer 6 and the scratch-resistant layer 7 on the surface of the substrate layer 1. For example, after forming the substrate protective layer 6 and the scratch-resistant layer 7 on the surface of the substrate layer 1, the barrier layer 3 may be formed on the surface of the substrate layer 1 opposite the substrate protective layer 6 side.

As described above, a laminate is formed comprising, from outside in, scratch-resistant layer 7, substrate protective layer 6, substrate layer 1, optional adhesive layer 2, barrier layer 3, optional adhesive layer 5, and heat-sealable resin layer 4. To strengthen the adhesion of optional adhesive layer 2 and adhesive layer 5, the laminate may be further subjected to heat treatment. Furthermore, as described above, a colored layer may be provided between substrate layer 1 and barrier layer 3.

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

Specifically, an electricity storage device using the electricity storage device packaging material of the present disclosure is provided by covering an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte with the electricity storage device packaging material of the present disclosure, with metal terminals connected to the positive electrode and negative electrode protruding outward, so that a flange portion (a region where the heat-sealable resin layers contact each other) is formed around the periphery of the electricity storage device element, and the heat-sealable resin layers of the flange portion are heat-sealed to form a hermetic seal. When an electricity storage device element is housed in a package formed from the electricity storage device packaging material of the present disclosure, the package is formed so that the heat-sealable resin portion of the electricity storage device packaging material of the present disclosure faces inward (the surface that contacts the electricity storage device element).

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

The present disclosure will be explained in detail below using examples and comparative examples. However, the present disclosure is not limited to the examples.

<Manufacturing of exterior materials for electricity storage devices>
Example 1
An oriented nylon (ONy) film (thickness: 15 μm) was prepared as the substrate layer. Furthermore, aluminum foil (JIS H4160:1994 A8021H-O (thickness: 35 μm)) was prepared as the barrier layer. Next, the barrier layer and the substrate layer were laminated by dry lamination using a two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound), followed by aging treatment to produce a substrate layer/adhesive layer/barrier layer laminate. Both sides of the aluminum foil were subjected to a chemical conversion treatment. The chemical conversion treatment of the aluminum foil was performed by roll coating both sides of the aluminum foil with a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, so that the coating amount of chromium was 10 mg/m ² (dry mass), followed by baking.

Next, maleic anhydride-modified polypropylene as an adhesive layer (20 μm thick) and random polypropylene as a heat-sealable resin layer (20 μm thick) were co-extruded onto the barrier layer of each laminate obtained above, thereby laminating the adhesive layer/heat-sealable resin layer onto the barrier layer.

Next, a resin composition containing barium sulfate (average particle diameter approximately 1 μm), resin (polyurethane formed from a mixture of one type of polyol compound and an aliphatic isocyanate compound), and polystyrene-based organic particles (particle diameter approximately 2 μm) was applied to the surface of the substrate layer of the resulting laminate using gravure printing to form a substrate protective layer (average film thickness 0.77 μm). Furthermore, a resin composition containing silica particles (average particle diameter approximately 1.5 μm), resin (polyurethane formed from a mixture of two types of polyol compounds and an aliphatic isocyanate compound), and polystyrene-based organic particles (particle diameter approximately 2 μm) was applied to the surface of the substrate protective layer using gravure printing to form a scratch-resistant layer (average film thickness 0.99 μm). This resulted in a laminate consisting of, from outside in, the scratch-resistant layer (average film thickness 0.99 μm), substrate protective layer (average film thickness 0.77 μm), substrate layer (15 μm), adhesive layer (3 μm), barrier layer (35 μm), adhesive layer (20 μm), and heat-sealable resin layer (20 μm).

Example 2
A laminate was obtained in the same manner as in Example 1, except that the average film thickness of the substrate protective layer was 0.53 μm and the average film thickness of the scratch-resistant layer was 1.34 μm, in which the scratch-resistant layer (average film thickness 1.34 μm)/substrate protective layer (average film thickness 0.53 μm)/substrate layer (15 μm)/adhesive layer (3 μm)/barrier layer (35 μm)/adhesive layer (20 μm)/thermally adhesive resin layer (20 μm) were laminated in this order from the outside.

Comparative Example 1
A laminate was obtained in the same manner as in Example 1, except that the resin composition for forming the scratch-resistant layer was applied twice by gravure printing without providing a substrate protective layer, so that the average film thickness of the scratch-resistant layer was 2.53 μm, and in which the scratch-resistant layer was laminated in the order from outside to inside, the scratch-resistant layer (average film thickness 2.53 μm)/substrate layer (15 μm)/adhesive layer (3 μm)/barrier layer (35 μm)/adhesive layer (20 μm)/thermally adhesive resin layer (20 μm).

Comparative Example 2
A laminate having, from the outside in order, a substrate protective layer (average film thickness 1.54 μm)/substrate layer (15 μm)/adhesive layer (3 μm)/barrier layer (35 μm)/adhesive layer (20 μm)/thermally adhesive resin layer (20 μm) laminated therein was obtained in the same manner as in Example 1, except that no scratch-resistant layer was provided and the resin composition for forming the substrate protective layer was applied twice by gravure printing to set the average film thickness of the substrate protective layer to 1.54 μm.

<Average film thickness>
The average film thicknesses of the scratch-resistant layer and the substrate protective layer of the laminate constituting the electrical storage device exterior material were measured and calculated as follows. A cross-sectional image of a cross section in the thickness direction of the laminate constituting the electrical storage device exterior material was obtained using a scanning electron microscope (SEM) under the conditions shown below. Next, for the cross-sectional image, the cross-sectional areas of the scratch-resistant layer and the substrate protective layer were each measured by image analysis. At this time, the horizontal length of the measurement area of the cross-sectional area (the length perpendicular to the thickness direction of the laminate) was 25.4 μm. Next, the average film thicknesses (μm) of the scratch-resistant layer and the substrate protective layer were calculated by dividing the obtained area by the horizontal length (25.4 μm). When measuring and calculating the total average film thickness of the scratch-resistant layer and the substrate protective layer, the cross-sectional areas of the scratch-resistant layer and the substrate protective layer in the same measurement area were simultaneously measured, and the obtained area was divided by the horizontal length (25.4 μm) of the measurement area to calculate the average film thickness (μm) of the scratch-resistant layer and the substrate protective layer combined.
(conditions)
Equipment: Hitachi High-Technologies S-4800
Acceleration voltage: 30 kV
Emission current: 10 μA
Detector: Transmission electron detector Tilt: None Observation magnification: 5000x Cross-section processing method:
The sample was cut into strips and embedded in resin. After the resin hardened, a rough cross section was prepared and the surface was polished. After that, the sample was stained with ruthenic acid for 2-3 hours, and ultrathin sections (thickness: approximately 100 nm) were prepared using a microtome. A diamond knife was used.

When particles with a diameter larger than the average film thickness of the scratch-resistant layer were observed in cross-sectional images (measurement area length 25.4 μm) of the exterior materials for electricity storage devices, one particle with a diameter of 1.11 μm was observed in the scratch-resistant layer of Example 1, and one particle with a diameter of 1.47 μm was observed in the scratch-resistant layer of Example 2. Furthermore, no particles with a diameter larger than the average film thickness of the scratch-resistant layer were observed in the scratch-resistant layer of Comparative Example 1, but relatively large particles with diameters of 1.97 μm, 1.51 μm, and 1.86 μm were observed.

Furthermore, a cross-sectional image of the scratch-resistant layer of the exterior material for an electricity storage device of Example 1 was obtained using a scanning electron microscope (SEM) under the conditions shown below, and the number of particles that appeared to have a particle diameter approximately equal to or greater than the average film thickness was counted. It was found that approximately 60 such particles were present within a width of approximately 500 to 600 μm.
(SEM conditions)
Equipment: Hitachi High-Technologies S-4800
Acceleration voltage: 5 kV
Emission current: 20 μA
Detector: Secondary electron detector Tilt: None Observation magnification: 5000x Number of observations: 23 Cross-section processing method: The sample was cut into strips and attached to a plastic plate with adhesive. After the adhesive had dried, the cross-section was prepared using a microtome. A diamond knife was used. The observations were also performed by scanning about five times to damage the sample (damage caused by the electron beam), after which the images were acquired.

<Hardness measured by nanoindentation method in a 23°C environment>
The device used was a nanoindenter (HYSITRON's "TI9"
The hardness was measured using a nanoindenter ("50 TriboIndenter"). A Berkovich indenter (TI-0039) was used as the indenter of the nanoindenter. First, in a relative humidity of 50% and a temperature of 23°C, the indenter was applied to the surface of the electrical storage device exterior material to be measured (the surface on which the scratch-resistant layer or the substrate protective layer is exposed, parallel to the thickness direction of each layer) from a direction perpendicular to the thickness direction, and the indenter was pressed from the surface to a load of 50 μN over 10 seconds, held in that state for 5 seconds, and then unloaded over 10 seconds. The average value of N = 5 measurements taken at different measurement locations was taken as the hardness. The results are shown in Table 1. The surface into which the indenter was pressed is the exposed cross section of the scratch-resistant layer or the substrate protective layer to be measured, obtained by cutting the electrical storage device exterior material in the thickness direction through the center. In addition, in measuring the hardness of the scratch-resistant layer or the substrate protective layer, the portion into which the indenter was pressed is the portion (resin portion) on the surface where no particles were present. When measuring the hardness of particles in the scratch-resistant layer or base material protective layer, the hardness is measured at the portion where particles are present on the surface. Cutting was carried out using a commercially available rotary microtome.

Examples 1 and 2 and Comparative Example 1 share the same resin in the scratch-resistant layer, and the hardness of the resin in the scratch-resistant layer of the electrical storage device exterior materials of Examples 1 and 2 and Comparative Example 1 was 218 MPa.

Examples 1 and 2 and Comparative Example 2 share the same resin in the substrate protective layer, and the hardness of the resin in the substrate protective layer of the electrical storage device exterior materials of Examples 1 and 2 and Comparative Example 2 was 23 MPa.

Examples 1 and 2 and Comparative Examples 1 and 2 share the same organic particles in the scratch-resistant layer or substrate protective layer, and the hardness of the organic particles in the electrical storage device exterior materials of Examples 1 and 2 and Comparative Examples 1 and 2 was 496 MPa.

<Scratch resistance evaluation>
A Gakushin-type abrasion fastness tester AB-301 (manufactured by Tester Sangyo Co., Ltd.) was used as the abrasion resistance evaluation device. The exterior material for an electricity storage device was attached to the table of the abrasion tester, and a dry paper cloth (Kimwipe, manufactured by Nippon Paper Crecia Co., Ltd.) was attached to the tip of the arm (friction element) at the top of the abrasion tester. Next, the surface of the scratch-resistant layer of the exterior material for an electricity storage device was rubbed back and forth 200 times with the cloth. The conditions for the reciprocating rub were a load of approximately 500 gf and 1 reciprocating stroke per second. The cloth was impregnated with 10 drops of ethanol, and 10 drops of ethanol were added to the cloth every 50 reciprocating strokes. After the reciprocating rub, the exterior material for an electricity storage device was removed from the abrasion resistance evaluation device, and the condition of the rubbed area was visually inspected and evaluated using a single evaluation standard. The results are shown in Table 1.
(Evaluation criteria)
A: No injuries were found.
B: Scratches were observed, but there were 10 or fewer scratches.
C: More than 10 scratches were observed.

<Moldability evaluation>
The electrical storage device exterior material was cut into strips measuring 120 mm in the TD direction and 80 mm in the MD direction, which were used as test samples. A rectangular male mold measuring 31.6 mm in the MD direction and 54.5 mm in the TD direction (the surface had a maximum height roughness (nominal Rz value) of 1.6 μm, corner R2.0 mm, ridge R1.0 mm, as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Appendix 1 (Reference)) was placed between the male mold and a female mold with a clearance of 0.3 mm (the surface had a maximum height roughness (nominal Rz value) of 1.6 μm, corner R2.0 mm, ridge R1.0 mm, as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Appendix 1 (Reference)). The maximum height roughness (nominal Rz value) of the comparative surface roughness standard specimen, as specified in Table 2, is 3.2 μm. Using a straight mold (corner R2.0 mm, ridge R1.0 mm), the test sample was placed on the female mold with the sealant layer side facing the male mold, and the test sample was pressed with a pressure (surface pressure) of 0.1 MPa to perform cold forming (single-stage drawing). The corners of the recesses of the test sample after molding were observed with a scanning electron microscope to examine the outermost layer (the scratch-resistant layer in Examples 1 and 2 and Comparative Example 1, and the substrate protective layer in Comparative Example 2), and the moldability was evaluated according to the following criteria. The results are shown in Table 1.
(Evaluation criteria)
A: No cracks were observed.
B: Cracks were observed, but the substrate layer was not exposed.
C: Cracks were observed, and the substrate layer was exposed.

The exterior packaging materials for electricity storage devices in Examples 1 and 2 are composed of a laminate having, in this order, a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-sealable resin layer. The scratch-resistant layer contains inorganic particles and resin, and the combined film thickness of the scratch-resistant layer and substrate protective layer is 10 μm or less. This provides excellent scratch resistance and effectively suppresses cracking at corners due to molding.

As described above, the present disclosure provides the following aspects of the invention.
Item 1. The laminate is composed of at least a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-sealable resin layer in this order,
the scratch-resistant layer contains inorganic particles and a resin,
The exterior material for an electricity storage device, wherein the average film thickness of the scratch-resistant layer and the base material protective layer combined is 10 μm or less.
Item 2. The packaging material for an electricity storage device according to Item 1, wherein the scratch-resistant layer contains particles having a particle diameter larger than the average film thickness of the scratch-resistant layer.
Item 3. The packaging material for an electricity storage device according to Item 1 or 2, wherein the substrate protective layer contains particles having a particle diameter larger than the average film thickness of the substrate protective layer.
Item 4. The exterior material for an electricity storage device according to Item 2 or 3, wherein the particle diameter of the large particles observed with a scanning electron microscope in a cross section in the thickness direction of the scratch-resistant layer and the base protective layer is 1.0 μm or more and 5.0 μm or less.
Item 5. The exterior material for an electricity storage device according to any one of Items 2 to 4, wherein when the hardness of the large particles and the resin in a cross section in the thickness direction of the scratch-resistant layer is measured by a nanoindentation method in a 23°C environment, the hardness of the large particles is greater than the hardness of the resin.
Item 6. The exterior packaging material for an electricity storage device according to any one of Items 2 to 5, wherein the difference in hardness between the large particles and the resin is 100 MPa or more.
Item 7. The exterior material for an electricity storage device according to any one of Items 2 to 6, wherein the large particles in a cross section in the thickness direction of the scratch-resistant layer have a hardness of 400 MPa or more as measured by a nanoindentation method in a 23°C environment.
Item 8. The exterior packaging material for an electricity storage device according to any one of Items 2 to 7, wherein the large particles are organic particles.
Item 9. The packaging material for an electricity storage device according to any one of Items 1 to 8, wherein the scratch-resistant layer and the base material protective layer each contain different resins.
Item 10. The packaging material for an electricity storage device according to any one of Items 1 to 9, wherein when hardness is measured by a nanoindentation method for a cross section in the thickness direction of the scratch-resistant layer and the base protective layer in a 23°C environment, the hardness of the resin of the scratch-resistant layer is greater than the hardness of the resin of the base protective layer.
Item 11.
Item 11. The exterior packaging material for a storage battery device according to Item 10, wherein the difference in hardness between the resin of the scratch-resistant layer and the resin of the base material protective layer is 100 MPa or more.
Item 12. The exterior material for an electricity storage device according to any one of Items 1 to 11, wherein the hardness of the resin measured by a nanoindentation method on a cross section in the thickness direction of the scratch-resistant layer in a 23°C environment is 150 MPa or more.
Item 13. The exterior material for an electricity storage device according to any one of Items 1 to 12, wherein the resin hardness measured by a nanoindentation method on a cross section in the thickness direction of the substrate protective layer in a 23°C environment is 150 MPa or less.
Item 14. The exterior packaging material for an electricity storage device according to any one of Items 1 to 13, wherein the inorganic particles in the scratch-resistant layer are silica particles.
Item 15. The exterior packaging material for an electricity storage device according to any one of Items 1 to 14, wherein the substrate protective layer contains inorganic particles and a resin.
Item 16. The exterior packaging material for an electricity storage device according to Item 15, wherein the inorganic particles of the base material protective layer are barium sulfate.
Item 17. The packaging material for an electricity storage device according to any one of Items 1 to 16, wherein the scratch-resistant layer has an average film thickness of 2.5 μm or less.
Item 18. The packaging material for an electricity storage device according to any one of Items 1 to 17, wherein the base protective layer has an average film thickness of 2.0 μm or less.
Item 19. The method includes a step of laminating at least a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-sealable resin layer in this order to obtain a laminate,
the scratch-resistant layer contains inorganic particles and a resin,
the average combined thickness of the scratch-resistant layer and the base material protective layer is 10 μm or less.
Item 20. An electricity storage device, in which an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the exterior material for an electricity storage device according to any one of Items 1 to 18.

REFERENCE SIGNS LIST 1 substrate layer 2 adhesive layer 3 barrier layer 4 heat-sealable resin layer 5 adhesive layer 6 substrate protective layer 7 scratch-resistant layer 10 exterior material for electricity storage device 61, 71 inorganic particles 62, 72 organic particles

Claims (31)

The laminate is composed of at least a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-sealable resin layer, in this order;
the scratch-resistant layer contains inorganic particles and a resin,
the average thickness of the scratch-resistant layer and the substrate protective layer combined is 10 μm or less;
The exterior material for an electricity storage device, wherein the base material protective layer is formed from at least one of an epoxy resin and a polyurethane. The laminate is composed of at least a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-sealable resin layer, in this order;
the scratch-resistant layer contains inorganic particles and a resin,
the average thickness of the scratch-resistant layer and the substrate protective layer combined is 10 μm or less;
The exterior material for an electricity storage device, wherein the scratch-resistant layer is formed from at least one of an epoxy resin and a polyurethane. The exterior packaging material for an electricity storage device according to claim 1 or 2, wherein the scratch-resistant layer contains particles having a particle diameter larger than the average film thickness of the scratch-resistant layer. The exterior material for an electricity storage device according to claim 3, wherein when the hardness of the large particles and the resin in a cross section in the thickness direction of the scratch-resistant layer is measured by nanoindentation in a 23°C environment, the hardness of the large particles is greater than the hardness of the resin. The exterior material for an electricity storage device according to claim 3 or 4, wherein the difference in hardness between the large particles of the scratch-resistant layer and the resin of the scratch-resistant layer is 100 MPa or more. The exterior packaging material for an electricity storage device according to any one of claims 3 to 5, wherein the hardness of the large particles in a cross section in the thickness direction of the scratch-resistant layer measured by nanoindentation in a 23°C environment is 400 MPa or more. The exterior packaging material for an electricity storage device according to any one of claims 1 to 6 or 2, wherein the substrate protective layer contains particles having a particle diameter larger than the average film thickness of the substrate protective layer. The exterior material for an electricity storage device according to any one of claims 3 to 7, wherein the particle diameter of the large particles observed with a scanning electron microscope in a cross section in the thickness direction of the scratch-resistant layer and the base protective layer is 1.0 μm or more and 5.0 μm or less. The exterior packaging material for an electricity storage device according to any one of claims 3 to 8, wherein the large particles are organic particles. The exterior packaging material for an electricity storage device according to any one of claims 1 to 9, wherein the scratch-resistant layer and the base material protective layer each contain different resins. The exterior packaging material for an electricity storage device according to any one of claims 1 to 10, wherein, when the hardness of a cross section in the thickness direction of the scratch-resistant layer and the base protective layer is measured by nanoindentation in a 23°C environment, the hardness of the resin of the scratch-resistant layer is greater than the hardness of the resin of the base protective layer. The exterior packaging material for an electricity storage device according to claim 11, wherein the difference in hardness between the resin of the scratch-resistant layer and the resin of the base material protective layer is 100 MPa or more. The exterior packaging material for an electricity storage device according to any one of claims 1 to 12, wherein the hardness of the resin measured by nanoindentation in a 23°C environment on a cross section in the thickness direction of the scratch-resistant layer is 150 MPa or more. The exterior packaging material for an electricity storage device according to any one of claims 1 to 13, wherein the hardness of the resin measured by nanoindentation in a 23°C environment on a cross section in the thickness direction of the base protective layer is 150 MPa or less. The exterior packaging material for an electricity storage device according to any one of claims 1 to 14, wherein the inorganic particles in the scratch-resistant layer are silica particles. The exterior packaging material for an electricity storage device according to any one of claims 1 to 15, wherein the substrate protective layer contains inorganic particles and a resin. The exterior material for an electricity storage device according to claim 16, wherein the inorganic particles of the base protective layer are barium sulfate. The exterior packaging material for an electricity storage device according to any one of claims 1 to 17, wherein the average film thickness of the scratch-resistant layer is 2.5 μm or less. The exterior packaging material for an electricity storage device according to any one of claims 1 to 18, wherein the average film thickness of the substrate protective layer is 2.0 μm or less. The electrical storage device packaging material according to any one of claims 1 to 19, wherein the electrical storage device packaging material is colored. The electrical storage device exterior packaging material according to any one of claims 1 to 20, wherein at least one of the scratch-resistant layer and the substrate protective layer contains a colorant. an adhesive layer between the substrate layer and the barrier layer;
The packaging material for an electricity storage device according to any one of claims 1 to 21, wherein the adhesive layer contains a colorant. The exterior packaging material for an electricity storage device according to any one of claims 1 to 22, comprising a colored layer between the base layer and the barrier layer. The electrical storage device packaging material according to any one of claims 1 to 23, wherein the barrier layer includes at least one of aluminum alloy foil and stainless steel foil. an adhesive layer is provided between the barrier layer and the heat-sealable resin layer,
The packaging material for an electricity storage device according to any one of claims 1 to 24, wherein the adhesive layer has a thickness of 20 µm or less. an adhesive layer is provided between the barrier layer and the heat-sealable resin layer,
The packaging material for an electricity storage device according to any one of claims 1 to 24, wherein the adhesive layer has a thickness of more than 20 µm and not more than 50 µm. an adhesive layer is provided between the barrier layer and the heat-sealable resin layer,
The adhesive layer 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. The exterior material for a storage battery device according to any one of claims 1 to 26. an adhesive layer is provided between the barrier layer and the heat-sealable resin layer,
The packaging material for an electricity storage device according to any one of claims 1 to 27, wherein the adhesive layer contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin. The method includes a step of laminating at least a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-fusible resin layer in this order to obtain a laminate,
the scratch-resistant layer contains inorganic particles and a resin,
the average thickness of the scratch-resistant layer and the substrate protective layer combined is 10 μm or less;
The method for producing an exterior material for an electricity storage device, wherein the base material protective layer is formed from at least one of an epoxy resin and a polyurethane. The method includes a step of laminating at least a scratch-resistant layer, a substrate protective layer, a substrate layer, a barrier layer, and a heat-fusible resin layer in this order to obtain a laminate,
the scratch-resistant layer contains inorganic particles and a resin,
the average thickness of the scratch-resistant layer and the substrate protective layer combined is 10 μm or less;
The method for producing an exterior material for an electricity storage device, wherein the scratch-resistant layer is formed from at least one of an epoxy resin and a polyurethane. An electricity storage device, wherein an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the exterior packaging material for an electricity storage device according to any one of claims 1 to 28.