Exterior material for power storage device, manufacturing method thereof, and power storage device

Abstract

To provide an exterior material for a power storage device in which the occurrence of cracking and peeling of a surface coating layer due to molding of the exterior material for the power storage device is suppressed.SOLUTION: An exterior material for a power storage device is composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealing resin layer from the outside, and the surface coating layer contains a resin and particles, and in an environment in which the temperature is 23°C, the hardness of the resin of the surface coating layer measured by the nanoindentation method with respect to the cross section in the thickness direction of the surface coating layer is 420.4 MPa or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an exterior material for an electricity storage device, a method for producing the same, and an electricity storage device. [Background technology]

[0002] Various types of electricity storage devices have been developed, and in all of them, exterior materials are essential components for sealing electricity storage device elements such as electrodes and electrolytes. Conventionally, metal exterior materials have been widely used as exterior materials for electricity storage devices.

[0003] Meanwhile, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., there has been a demand for electricity storage devices to have a variety of shapes as well as to be thinner and lighter in weight. However, the metallic exterior materials for electricity storage devices that have been widely used in the past have the drawbacks of being difficult to keep up with the diversification of shapes and also having limitations on how much they can be made lighter.

[0004] Therefore, in recent years, a film-like laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated in this order has been proposed as an exterior material for an electricity storage device that can be easily processed into a variety of shapes and can be made thinner and lighter (see, for example, Patent Document 1).

[0005] In such an electrical storage device packaging material, a recess is generally formed by cold forming, and electrical storage device elements such as electrodes and electrolyte are placed in the space formed by the recess, and the heat-sealable resin layer is heat-sealed (thermally sealed) to obtain an electrical storage device in which the electrical storage device elements are housed inside the electrical storage device packaging material. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-287971 Summary of the Invention [Problem to be solved by the invention]

[0007] In an exterior material for an electricity storage device composed of a film-like laminate, a surface coating layer containing particles may be provided on the outside of the base layer to give the outer surface a matte design.

[0008] However, as described above, since the electrical storage device packaging material is subjected to molding, the electrical storage device packaging material provided with a surface coating layer containing particles is also required to have excellent moldability. Specifically, it is required to suppress the occurrence of cracking or peeling of the surface coating layer during molding of the electrical storage device packaging material.

[0009] Under these circumstances, a main object of the present disclosure is to provide an exterior material for an electricity storage device in which the occurrence of cracking or peeling of the surface coating layer due to molding of the exterior material for an electricity storage device is suppressed. [Means for solving the problem]

[0010] The inventors of the present disclosure conducted extensive research to solve the above-mentioned problems, and as a result, found that a packaging material for an electricity storage device composed of a laminate including, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, wherein the surface coating layer contains a resin and particles, and the hardness of the resin in the surface coating layer is 420.4 MPa or less as measured by nanoindentation at a cross section in the thickness direction of the surface coating layer in a 23°C environment, the hardness being 420.4 MPa or less, the hardness being 420.4 MPa or less as measured by nanoindentation at a cross section in the thickness direction of the surface coating layer in a 23°C environment, the packaging material for an electricity storage device, can suppress the occurrence of cracking or peeling of the surface coating layer due to molding of the packaging material for an electricity storage device.

[0011] 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 a surface coating layer, a base material layer, a barrier layer, and a thermally adhesive resin layer, in this order from the outside, the surface coating layer contains a resin and particles, An exterior material for an electricity storage device, wherein the hardness of the resin of the surface coating layer, measured by nanoindentation in a cross section in the thickness direction of the surface coating layer in a 23°C environment, is 420.4 MPa or less. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide an electrical storage device packaging material that suppresses cracking and peeling of the surface coating layer due to molding of the electrical storage device packaging material. The present disclosure also makes it possible to provide a method for manufacturing the electrical storage device packaging material, and an electrical storage device that uses the electrical storage device packaging material. [Brief explanation of the drawings]

[0013] [Figure 1] 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. [Figure 2] 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. [Figure 3] 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. DETAILED DESCRIPTION OF THE INVENTION

[0014] The electrical storage device packaging material of the present disclosure is composed of a laminate including, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, the surface coating layer containing a resin and particles, and is characterized in that the hardness of the resin of the surface coating layer, measured by nanoindentation at a cross section in the thickness direction of the surface coating layer in an environment of 23° C., is 420.4 MPa or less. By having this configuration, the electrical storage device packaging material of the present disclosure is able to suppress cracking and peeling of the surface coating layer during molding of the electrical storage device packaging material.

[0015] The packaging material for an electricity storage device of the present disclosure will be described in detail below. In this specification, a numerical range indicated by "to" means "not less than" or "not more than." For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less.

[0016] 1.Layer structure and physical properties of exterior materials for energy storage devices As shown in FIGS. 1 to 3 , for example, an electrical storage device packaging material 10 according to the present disclosure is composed of a laminate including, in order from the outside, a surface coating layer 6, a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4. In the electrical storage device packaging material 10, the surface coating layer 6 is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. When assembling an electrical storage device using the electrical storage device packaging material 10 and an electrical storage device element, the electrical storage device element is housed in a space formed by heat-sealing the peripheral portions of the electrical storage device packaging material 10 with the heat-sealable resin layers 4 of the electrical storage device packaging material 10 facing each other. In the laminate constituting the electrical storage device packaging material 10 according to the present disclosure, with the barrier layer 3 as the reference, the heat-sealable resin layer 4 side relative to the barrier layer 3 is the inner side, and the surface coating layer 6 side relative to the barrier layer 3 is the outer side.

[0017] As shown in Figures 2 and 3, for example, the packaging material 10 for an electricity storage device may have an adhesive layer 2 between the base material layer 1 and the barrier layer 3, if necessary, for the purpose of increasing the adhesion between these layers. Although not shown, a colored layer may be provided between the base material layer 1 and the barrier layer 3. As shown in Figure 3, for example, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-sealable resin layer 4, if necessary, for the purpose of increasing the adhesion between these layers.

[0018] The thickness of the laminate constituting the electrical storage device packaging material 10 is not particularly limited, but from the viewpoints of cost reduction, energy density improvement, etc., it is preferably about 180 μm or less, about 160 μm or less, about 155 μm or less, about 140 μm or less, about 130 μm or less, and about 120 μm or less. From the viewpoint of maintaining the function of the electrical storage device packaging material to protect the electrical storage device elements, it is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, and about 80 μm or more. Preferred ranges include, for example, about 35 to 180 μm, about 35 to 160 μm, and about 35 to 180 μm. Examples include about 5 to 155 μm, about 35 to 140 μm, about 35 to 130 μm, about 35 to 120 μm, about 45 to 180 μm, about 45 to 160 μm, about 45 to 155 μm, about 45 to 140 μm, about 45 to 130 μm, about 45 to 120 μm, about 60 to 180 μm, about 60 to 160 μm, about 60 to 155 μm, about 60 to 140 μm, about 60 to 130 μm, about 60 to 120 μm, about 80 to 180 μm, about 80 to 160 μm, about 80 to 155 μm, about 80 to 140 μm, about 80 to 130 μm, and about 80 to 120 μm. Of these, about 80 to 130 μm is particularly preferred.

[0019] In the electrical storage device packaging material 10 of the present disclosure, the hardness of the resin in the surface coating layer 6 is 420.4 MPa or less when measured by nanoindentation in a cross section in the thickness direction of the surface coating layer 6 in an environment of 23°C. In the electrical storage device packaging material 10, since the surface coating layer 6 has the above hardness in an environment of 23°C, the occurrence of cracking or peeling of the surface coating layer when the electrical storage device packaging material is formed in an environment of room temperature is suppressed.

[0020] From the viewpoint of more effectively suppressing the occurrence of cracking and peeling of the surface coating layer due to molding of the exterior packaging material for an electricity storage device, the exterior packaging material 10 for an electricity storage device of the present disclosure has a resin hardness of the surface coating layer 6 measured by nanoindentation in a 23°C environment for a cross section in the thickness direction of the surface coating layer 6 of preferably about 350.4 MPa or less, more preferably about 310.4 MPa or less, and also preferably about 20.0 MPa or more, more preferably about 22.5 MPa or more, even more preferably about 25.5 MPa or more, even more preferably about 50.0 MPa or more, even more preferably about 100.0 MPa or more, and even more preferably about 150.0 MPa or more, with preferred ranges being as follows: , about 20.0 to 420.4 MPa, about 20.0 to 350.4 MPa, about 20.0 to 310.4 MPa, about 22.5 to 420.4 MPa, about 22.5 to 350.4 MPa, about 22.5 to 310.4 MPa, about 25.5 to 420.4 MPa, about 25.5 to 350.4 MPa, about 25.5 to 310.4 MPa, about 50.0 to 420.4 MPa, about 50.0 to 350.4 MPa, about 50.0 to 310.4 MPa, about 100.0 to 420.4 MPa, about 100.0 to 350.4 MPa, about 100.0 to 310.4 MPa, about 150.0 to 420.4 MPa, about 150.0 to 350.4 MPa, and about 150.0 to 310.4 MPa. Among these, a hardness of about 150.0 to 310.4 MPa is particularly preferable. More specifically, in the present invention, excellent formability means that the matte design of the surface coating layer is prevented from being damaged by molding the exterior material 10 for an electricity storage device, and that cracking or peeling of the surface coating layer due to room-temperature molding is prevented. The hardness measured by the nanoindentation method in a 23°C environment is measured as follows.

[0021] [Hardness measured by nanoindentation at 23°C] The hardness is measured using a nanoindenter (e.g., HYSITRON's "TI950 TriboIndenter"). A Berkovich indenter (e.g., TI-0039) is used as the indenter for the nanoindenter. First, in an environment of 50% relative humidity and 23°C, the indenter is placed perpendicular to the thickness direction on the surface of the surface coating layer of the electrical storage device exterior material (the surface where the surface coating layer is exposed, parallel to the thickness direction of each layer). The indenter is pressed into the surface coating layer from the surface up to a load of 50 μN over 10 seconds, held in this state for 5 seconds, and then unloaded over 10 seconds. The average value of N=5 measurements taken at different measurement points is used as the hardness. The surface into which the indenter is pressed is the resin portion where the cross section of the surface coating layer is exposed, obtained by cutting the electrical storage device exterior material in the thickness direction through the center. Cutting is performed using a commercially available rotary microtome. Furthermore, when preparing a test sample by obtaining a packaging material for an electricity storage device from an electricity storage device, the packaging material for an electricity storage device is obtained from a location of the electricity storage device that is less affected by molding, such as the top or side surface.

[0022] The hardness measured by nanoindentation in a 23°C environment can be adjusted by the composition (type of resin, content) of the resin composition forming the surface coating layer 6, curing conditions, molecular weight, number of functional groups, crosslinking density, bulkiness of the substituents, etc.

[0023] 2. Each layer that forms the exterior material for the energy storage device [Surface coating layer 6] The exterior packaging material 10 for an electricity storage device according to the present disclosure has a surface coating layer 6 on the outside of the base material layer 1 for the purpose of imparting a matte design to the outer surface of the exterior packaging material 10 for an electricity storage device. The surface coating layer 6 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.

[0024] The surface coating layer 6 contains a resin and particles. Examples of the particles include inorganic particles and organic particles. The particles contained in the surface coating layer 6 may be one type or two or more types. It is also preferable to use inorganic particles and organic particles in combination. The shape of the particles is not particularly limited, and examples include spherical, fibrous, plate-like, amorphous, and scaly shapes.

[0025] The average particle diameter of the particles is not particularly limited, but may be, for example, about 0.01 to 5 μm from the viewpoint of imparting a matte design to the exterior material 10 for an electricity storage device. The average particle diameter of the particles is the median diameter measured with a laser diffraction / scattering particle size distribution measuring device. The average particle diameter of the particles is preferably equal to or less than the thickness of the surface coating layer 6.

[0026] The inorganic particles are not particularly limited as long as they can impart a matte finish to the surface coating layer 6, and examples thereof include particles of 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, nickel, etc. Among these, silica particles are particularly preferred.

[0027] Furthermore, the organic particles are not particularly limited as long as they can give the surface coating layer 6 a matte finish, and examples include particles of nylon, polyacrylate, polystyrene, styrene-acrylic copolymer, polyethylene, benzoguanamine, or crosslinked products thereof.

[0028] In measuring the hardness measured by nanoindentation in a 23°C environment, the hardness of the organic particles contained in the surface coating layer 6 can also be measured by pressing the indenter into a portion of the surface where organic particles are present and the cross section of the surface coating layer is exposed, the portion being obtained by cutting the exterior material for an electricity storage device in the thickness direction through the center of the exterior material. From the viewpoint of more effectively suppressing the occurrence of cracking or peeling of the surface coating layer during molding of the exterior material for an electrical storage device, the hardness of the organic particles measured in this manner is preferably about 300.0 MPa or more, more preferably about 400.0 MPa or more, and also preferably about 1500.4 MPa or less, more preferably about 1000.4 MPa or less, and even more preferably about 600.4 MPa or less. Preferred ranges include about 300.0 to 1500.4 MPa, about 300.0 to 1000.4 MPa, about 300.0 to 600.4 MPa, about 400.0 to 1500.4 MPa, about 400.0 to 1000.4 MPa, and about 400.0 to 600.4 MPa. Of these, about 400.0 to 600.4 MPa is particularly preferred.

[0029] The content of particles contained in the surface coating layer 6 is not particularly limited, as long as the hardness measured by nanoindentation in a 23°C environment is 420.4 MPa or less. However, the content is preferably at least about 3 parts by mass, more preferably at least about 10 parts by mass, and also preferably at most about 30 parts by mass, more preferably at most about 20 parts by mass, relative to 100 parts by mass of the resin in the resin composition that forms the surface coating layer 6. Preferred ranges include about 3 to 30 parts by mass, about 3 to 20 parts by mass, about 10 to 30 parts by mass, and about 10 to 20 parts by mass.

[0030] If the amount of particles present in the surface coating layer 6 is too large, the adhesion at the boundary between the resin and the particles will be weak, making it easier for cracks to occur at the boundary, so it is preferable to adjust the particle content to a small amount.

[0031] The resin contained in the resin composition forming the surface coating layer 6 is not particularly limited, as long as the hardness measured by nanoindentation in a 23°C environment is 420.4 MPa or less, but is preferably a curable resin. That is, the surface coating layer 6 is preferably composed of a cured resin composition containing a curable resin and particles. Specific examples of resins include polyvinylidene chloride, polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, phenolic resin, and modified versions of these resins. The resin may also be a copolymer of these resins or a modified version of the copolymer. Furthermore, the resin may also be a mixture of these resins. The resin is preferably a curable resin.

[0032] 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. Among these, two-component curing polyurethane is preferred.

[0033] Examples of two-component curing polyurethanes include polyurethanes containing a polyol compound as a base component and an isocyanate compound as a curing agent. Preferred examples of two-component curing polyurethanes include those using a polyol such as polyester polyol, polyether polyol, or acrylic polyol as a base component and an aromatic or aliphatic polyisocyanate as a curing agent. Furthermore, as the polyol compound, polyester polyols having hydroxyl groups on the side chains in addition to terminal hydroxyl groups in the repeating units are preferably used. 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). Further examples include polyfunctional isocyanate modified products obtained from 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. The term "aliphatic isocyanate compound" refers to an isocyanate having an aliphatic group but no aromatic ring, the term "alicyclic isocyanate compound" refers to an isocyanate having an alicyclic hydrocarbon group, and the term "aromatic isocyanate compound" refers to an isocyanate having an aromatic ring.

[0034] In the resin composition forming the surface coating layer 6, when the resin is polyurethane containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound, the hardness measured by the nanoindentation method in a 23°C environment can be adjusted, for example, by adjusting the ratio of the base agent to the curing agent.

[0035] At least one of the surface and the interior of the surface coating layer 6 may further contain additives such as lubricants, colorants, antiblocking agents, flame retardants, antioxidants, tackifiers, antistatic agents, waxes, etc., as described below, depending on the functionality to be provided to the surface coating layer 6 and its surface.

[0036] When the surface coating layer 6 contains a colorant, known colorants such as pigments and dyes can be used. A single colorant may be used, or two or more colorants may be mixed. Specific examples of colorants contained in the surface coating layer 6 include those exemplified in the section [Adhesive layer 2]. The preferred content of the colorant contained in the surface coating layer 6 is also the same as that described in the section [Adhesive layer 2].

[0037] The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method for applying a resin composition for forming the surface coating layer 6. When an additive is blended into the surface coating layer 6, a resin mixed with the additive may be applied.

[0038] If the amount of additive present in the surface coating layer 6 is too large, the adhesion at the boundary between the resin and the adhesive will be weak, making it easier for cracks to occur at the boundary, so it is preferable to adjust the content of the additive to the minimum necessary.

[0039] The thickness of the surface coating layer 6 is preferably 0.5 μm or more, more preferably 1 μm or more, from the viewpoint of more effectively suppressing the occurrence of cracking or peeling of the surface coating layer during molding of the exterior material for an electricity storage device, and is preferably 10 μm or less, more preferably 5 μm or less, with preferred ranges including about 0.5 to 10 μm, about 0.5 to 5 μm, about 1 to 10 μm, and about 1 to 5 μm.

[0040] 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 surface coating layer 6. 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, and N,N'-distearyl sebacic acid amide. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide. Specific examples of fatty acid ester amides include stearamidoethyl stearate. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N,N'-distearyl isophthalic acid amide, etc. The lubricants may be used singly or in combination of two or more.

[0041] When a lubricant is present on the surface of the surface coating layer 6, the amount of the lubricant is not particularly limited, but is preferably about 3 mg / m 2 or more, more preferably 4 to 15 mg / m 2 approximately, more preferably 5 to 14 mg / m 2 The degree of

[0042] The lubricant present on the surface of the surface coating layer 6 may be a lubricant that has been exuded from the surface coating layer 6, or a lubricant that has been applied to the surface of the surface coating layer 6.

[0043] [Base material layer 1] In the present disclosure, the substrate layer 1 is a layer provided for the purpose of, for example, functioning as a substrate of the packaging material for an electricity storage device. The substrate layer 1 is located between the surface coating layer 6 and the barrier layer 3 of the packaging material for an electricity storage device 10. Furthermore, when the adhesive layer 2 is present, the substrate layer 1 is located between the surface coating layer 6 and the adhesive layer 2.

[0044] There are no particular limitations on the material forming the base layer 1, as long as it functions as a base, i.e., has at least insulating properties. The base layer 1 can be formed using, for example, a resin, which may contain additives described below.

[0045] When the base layer 1 is formed of a resin, the base layer 1 may be, for example, a resin film formed of a resin, or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially stretched films and biaxially stretched films, with biaxially stretched films being preferred. Examples of stretching methods for forming biaxially stretched films include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying a resin include roll coating, gravure coating, and extrusion coating.

[0046] 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. Furthermore, it may also be a mixture of these resins.

[0047] Of these, preferred resins for forming the base layer 1 include polyester and polyamide.

[0048] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters in which ethylene terephthalate is the main repeating unit. Specific examples include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), and polyethylene (terephthalate / decanedicarboxylate). These polyesters may be used alone or in combination of two or more.

[0049] 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; and aromatic polyamides such as polyamide MXD6 (polymetaxylylene adipamide); alicyclic polyamides such as polyamide PACM6 (polybis(4-aminocyclohexyl)methane adipamide); polyamides copolymerized with a lactam component or an isocyanate component such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and polyamides such as copolymers of these. These polyamides may be used singly or in combination of two or more.

[0050] The base layer 1 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, preferably includes at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, more preferably includes 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 includes 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.

[0051] The base material layer 1 may be a single layer, or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or a 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 material layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base material layer 1.

[0052] Specific examples of laminates of two or more resin films in the base layer 1 include laminates of polyester film and nylon film, laminates of two or more nylon films, and laminates of two or more polyester films. Preferably, laminates of stretched nylon film and stretched polyester film, laminates of two or more stretched nylon films, and laminates of two or more stretched polyester films are preferred. 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, when the base layer 1 is a laminate of two or more resin films, it is preferred that the polyester resin film be located on the outermost side of the base layer 1, because polyester resins are less likely to discolor when an electrolyte solution adheres to their surface.

[0053] 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, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive may be, for example, about 2 to 5 μm. Alternatively, an anchor coat layer may 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 thickness of the anchor coat layer may be, for example, about 0.01 to 1.0 μm.

[0054] Furthermore, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present on at least one of the surface and the interior of the base material layer 1. Only one type of additive may be used, or two or more types may be mixed and used.

[0055] The thickness of the base layer 1 is not particularly limited as long as it functions as a base, and examples thereof include about 3 to 50 μm, about 3 to 35 μm, and about 3 to 25 μm. When the base layer 1 is a laminate of two or more resin films, the thickness of each resin film constituting each layer is preferably about 2 to 25 μm.

[0056] [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.

[0057] The adhesive layer 2 is formed from an adhesive capable of bonding the base material 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 hot pressure 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.

[0058] Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymer polyamides; polyolefin-based 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 component resins can be increased by using an appropriate curing agent in combination. The curing agent is selected appropriately from polyisocyanates, multifunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, and the like, depending on the functional groups of the adhesive components.

[0059] Examples of polyurethane adhesives include polyurethane adhesives containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound. Two-component curing polyurethane adhesives are preferred, using 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, as the polyol compound, polyester polyols having hydroxyl groups on the side chains in addition to terminal hydroxyl groups in the repeating unit are preferably used. 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). Further examples include polyfunctional isocyanate modified products obtained from one or more of these diisocyanates. Furthermore, a polymer (e.g., a trimer) can also be used as the polyisocyanate compound. Examples of such polymers include adducts, biurets, and nurates. Forming the adhesive layer 2 from a polyurethane adhesive provides the electrical storage device exterior packaging material with excellent electrolyte resistance, and prevents the base layer 1 from peeling off even if the electrolyte adheres to the side surface.

[0060] The adhesive layer 2 may contain other components as long as they do not impair adhesion, such as colorants, thermoplastic elastomers, tackifiers, and particles. The adhesive layer 2 contains a colorant, which allows the electrical storage device packaging material to be colored. Known colorants, such as pigments and dyes, can be used. Only one type of colorant may be used, or two or more types may be mixed together.

[0061] The type of pigment is not particularly limited as long as it does not impair the adhesiveness 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, while examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, and other examples include finely powdered mica and fish scale foil.

[0062] Among colorants, carbon black is preferred in order to give the exterior appearance of the electrical storage device packaging material a black color, for example.

[0063] The average particle size of the pigment is not particularly limited and may be, for example, about 0.05 to 5 μm, and preferably about 0.08 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution measuring device.

[0064] The content of the pigment in the adhesive layer 2 is not particularly limited as long as it colors the packaging material for an electricity storage device, and may be, for example, about 5 to 60 mass %, and preferably 10 to 40 mass %.

[0065] 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 may be, for example, about 1 μm or more, or about 2 μm or more. The thickness of the adhesive layer 2 may be, for example, about 10 μm or less, or about 5 μm or less. Preferred ranges for the thickness of the adhesive layer 2 include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[0066] [Colored layer] The colored layer is a layer that is provided between the base material layer 1 and the barrier layer 3 as needed (not shown). 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. A colored layer may also 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. A colored adhesive layer 2 and a colored layer may be provided between the base material layer 1 and the barrier layer 3.

[0067] 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 the colorant. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[0068] Specific examples of the colorant contained in the colored layer include the same as those exemplified in the section [Adhesive layer 2].

[0069] [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.

[0070] Examples of the barrier layer 3 include metal foils, vapor-deposited films, and resin layers having 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 mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of 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 constituting 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.

[0071] From the viewpoint of suppressing the occurrence of pinholes and cracks during molding of the electrical storage device packaging 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 more effectively suppressing the occurrence of pinholes and cracks during molding, the aluminum alloy foil 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, more preferably 0.5 to 2.0% by mass. By ensuring that the iron content is 0.1% by mass or more, an electrical storage device packaging material in which the occurrence of pinholes and cracks during molding is effectively suppressed can be obtained. By ensuring that the iron content is 9.0% by mass or less, an electrical storage device packaging material with improved flexibility can be obtained. Examples of soft aluminum alloy foils include aluminum alloy foils having a composition 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 be added as needed. Softening can be achieved by annealing or other methods.

[0072] Examples of stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. Furthermore, from the viewpoint of suppressing the occurrence of pinholes and cracks during the molding of the exterior material for an electricity storage device, the stainless steel foil is preferably made of austenitic stainless steel.

[0073] Specific examples of austenitic stainless steels that can be used to form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS301 or SUS304 being particularly preferred.

[0074] In the case of a metal foil, the thickness of the barrier layer 3 should be sufficient to at least function as a barrier layer that prevents moisture penetration, and is, for example, about 9 to 200 μm. The thickness of the barrier layer 3 is, for example, preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 3 is, for example, preferably about 10 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. The thickness of the barrier layer 3 is preferably in the range of about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. Of these, about 25 to 40 μm is particularly preferred. When the barrier layer 3 is made of an aluminum alloy foil, the above-mentioned ranges are particularly preferred. When the barrier layer 3 is made of a 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 about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0075] Furthermore, when the barrier layer 3 is a metal foil, it is preferable that a corrosion-resistant coating be provided on at least the surface opposite the substrate layer to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film formed by applying, to the surface of the barrier layer, for example, a hydrothermal conversion treatment such as boehmite treatment, a chemical conversion treatment, anodizing treatment, a nickel or chromium plating treatment, or a corrosion prevention treatment such as applying a coating agent, to provide the barrier layer with corrosion resistance. The corrosion-resistant coating may be formed by one type of treatment or a combination of two or more types. Furthermore, not only one layer but also multiple layers can be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved by 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.

[0076] The corrosion-resistant coating prevents delamination between the barrier layer (e.g., aluminum alloy foil) and the substrate layer during molding of the exterior packaging material for an electricity storage device, prevents dissolution and corrosion of the barrier layer surface due to hydrogen fluoride produced by the reaction between the electrolyte and water, and in particular prevents dissolution and corrosion of aluminum oxide present on the barrier layer surface when the barrier layer is an aluminum alloy foil, and also improves the adhesion (wettability) of the barrier layer surface, thereby preventing delamination between the substrate layer and the barrier layer during heat sealing and between the substrate layer and the barrier layer during molding.

[0077] Various corrosion-resistant coatings formed by chemical conversion treatments are known, including corrosion-resistant coatings 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. Examples of 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. Examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid. Examples of 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 primarily composed of a metal phosphate such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, or Zn (zinc) phosphate, or a mixture of these metal salts, or a treatment solution primarily composed of a nonmetallic phosphate and a mixture of these nonmetallic salts, or a mixture of these with a synthetic resin, using 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 be a polymer such as a phenolic resin or an acrylic resin, or may be a chromate treatment using an aminated phenol polymer having repeating units represented by the following general formulas (1) to (4): In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more types.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. A derivative of polyacrylic acid, such as an ammonium salt, a sodium salt, or an amine salt of polyacrylic acid, is particularly preferred. In the present 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, or 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 and used.

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group, or a benzyl group. 1 and R 2 are the same or different and represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. 1 and R 2Examples of the alkyl group represented by X and R include linear or branched alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. 1 and R 2 Examples of the hydroxyalkyl group represented by the formula (1) include a linear or branched alkyl group having 1 to 4 carbon atoms 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. 1 and R 2 The alkyl group and hydroxyalkyl group represented by the formula (1) may be the same or different. In the 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 the formulas (1) to (4) is preferably about 500 to 1,000,000, and more preferably about 1,000 to 20,000. The aminated phenol polymer can be prepared, for example, by polycondensing a phenol compound or a naphthol compound with formaldehyde to produce a polymer comprising repeating units represented by the formula (1) or (3), and then polycondensing the polymer with formaldehyde and an amine (R 1 R 2 NH) to the functional group (-CHNR 1 R 2 The aminated phenol polymers can be used singly or in combination of two or more.

[0083] Another example of a corrosion-resistant coating is a thin film formed by a coating-type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of a rare earth element oxide sol, an anionic polymer, and a cationic polymer is applied. The coating agent may further contain phosphoric acid or a phosphate salt, and a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol has 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 from the perspective of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant coating can be used alone or in combination of two or more. The liquid dispersion medium for the rare earth element oxide sol can be 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 composed 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 a compound having a functional group selected from an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent. The phosphoric acid or phosphoric acid salt is preferably a condensed phosphoric acid or a condensed phosphate salt.

[0084] An 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 a barrier layer and baking the coating at 150°C or higher.

[0085] The corrosion-resistant coating may have a laminated structure, if necessary, by further laminating at least one of a cationic polymer and an anionic polymer, such as those mentioned above.

[0086] The composition of the corrosion-resistant film can be analyzed using, for example, time-of-flight secondary ion mass spectrometry.

[0087] 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, in the case of applying chromate treatment, the amount of the corrosion-resistant film formed on the surface of the barrier layer 3 is 2 It is desirable that the chromate compound is contained in an amount, in terms of chromium, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, the phosphorus compound in terms of phosphorus, and the aminated phenol polymer in an amount, in terms of phosphorus, of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, per unit area.

[0088] 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 or 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 the thickness of the corrosion-resistant coating, for example, by measuring the thickness of the coating with secondary ions consisting of Ce, P, and O (e.g., Ce2PO4 + , CePO4 - At least one of the following ions may be present: Cr, P, and O secondary ions (e.g., CrPO2 + , CrPO4 - Peaks derived from at least one of the above are detected.

[0089] The chemical conversion treatment is carried out by applying a solution containing a compound used to form a corrosion-resistant coating to the surface of the barrier layer by bar coating, roll coating, gravure coating, immersion, or other methods, and then heating the barrier layer to a temperature of approximately 70 to 200°C. Furthermore, before applying the chemical conversion treatment to the barrier layer, the barrier layer may be subjected to a degreasing treatment using an alkali immersion method, electrolytic cleaning, acid cleaning, electrolytic acid cleaning, or other methods. By performing such a degreasing treatment, the chemical conversion treatment of the surface of the barrier layer can be carried out more efficiently. Furthermore, using an acid degreasing agent prepared by dissolving a fluorine-containing compound in an inorganic acid for the degreasing treatment not only degreases the metal foil but also forms a passive metal fluoride. In such cases, only the degreasing treatment may be performed.

[0090] [Thermofusible resin layer 4] In the 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 exhibits the function of sealing the electricity storage device elements by heat-sealing the heat-sealable resin layers to each other when assembling the electricity storage device.

[0091] 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 polyolefin and acid-modified polyolefin, are preferred. The presence of a polyolefin skeleton in the resin constituting the heat-sealable resin layer 4 can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like. Furthermore, when the resin constituting the heat-sealable resin layer 4 is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wavenumber of 1760 cm. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around . When the thermally adhesive resin layer 4 is a layer made of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected when measured by infrared spectroscopy. However, if the degree of acid modification is low, the peak becomes small and may not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0092] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. Among these, polypropylene is preferred. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more.

[0093] The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, preferred are cyclic alkenes, and more preferred are norbornene.

[0094] Acid-modified polyolefins are polymers modified by block polymerization or graft polymerization of polyolefins with an acid component. Examples of acid-modified polyolefins include the above-mentioned polyolefins, copolymers of the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, and crosslinked polyolefins. Examples of acid components used for acid modification include carboxylic acids or anhydrides thereof, such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0095] The acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin by replacing it with an acid component, or by block polymerizing or graft polymerizing an acid component onto the 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 for the modification of the polyolefin.

[0096] Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0097] The thermally adhesive resin layer 4 may be formed of one type of resin alone or may be formed of a blend polymer of two or more types of resins. Furthermore, the thermally adhesive resin layer 4 may be formed of only one layer, or may be formed of two or more layers of the same or different resins.

[0098] Furthermore, the heat-sealable resin layer 4 may contain a lubricant, etc., as necessary. When the heat-sealable resin layer 4 contains a lubricant, the occurrence of pinholes and cracks during molding of the exterior packaging material for an electricity storage device can be suppressed. The lubricant is not particularly limited, and known lubricants can be used. The lubricants may be used alone or in combination of two or more.

[0099] The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of the lubricant include those exemplified for the base layer 1. The lubricant may be used alone or in combination of two or more.

[0100] When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount of the lubricant is not particularly limited, but from the viewpoint of suppressing the occurrence of pinholes and cracks during molding of the exterior material for an electricity storage device, it is preferably 10 to 50 mg / m 2 about 15 to 40 mg / m 2 The degree of

[0101] The lubricant present on the surface of the heat-sealable resin layer 4 may be a lubricant exuded from the resin constituting the heat-sealable resin layer 4, or a lubricant applied to the surface of the heat-sealable resin layer 4.

[0102] The thickness of the heat-sealable resin layer 4 is not particularly limited as long as it can heat-seal the heat-sealable resin layers to each other and function to seal the electricity storage device element, but may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described below is 10 μm or more, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 5 described below is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0103] [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.

[0104] The adhesive layer 5 is formed from a resin capable of bonding the barrier layer 3 and the heat-sealable resin layer 4. The resin used to form the adhesive layer 5 can be, for example, the same adhesive as exemplified for the adhesive layer 2. 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. The presence of a polyolefin skeleton in the resin constituting the adhesive layer 5 can be determined by, for example, infrared spectroscopy or gas chromatography-mass spectrometry, and the analysis method is not particularly limited. Furthermore, when the resin constituting the adhesive layer 5 is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wavenumber of 1760 cm. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around this point. However, if the degree of acid modification is low, the peak may be small and not be detected. In this case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0105] From the viewpoint of firmly bonding the barrier layer 3 and the heat-sealable resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. Particularly preferred examples of the acid-modified polyolefin include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0106] Furthermore, from the viewpoint of reducing the thickness of the electrical storage device packaging material while providing an electrical storage device packaging material that has excellent shape stability after molding, the adhesive layer 5 is more preferably a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of the acid-modified polyolefin include those mentioned above.

[0107] The adhesive layer 5 is preferably 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. It is particularly preferably 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 and a compound having an epoxy group. The adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, more preferably polyurethane and epoxy resin. A preferred polyester is, for example, an amide ester resin. Amide ester resins are generally produced by the reaction of a carboxyl group with an oxazoline group. The adhesive layer 5 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. In addition, if unreacted compounds of curing agents such as compounds having an isocyanate group, compounds having an oxazoline group, and epoxy resins remain in the adhesive layer 5, the presence of the unreacted compounds can be confirmed by a method selected from, for example, infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

[0108] Furthermore, from the viewpoint of further enhancing 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 COC 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 COC bond include curing agents having an oxazoline group, curing agents having an epoxy group, and polyurethane. 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.

[0109] The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively improving the adhesion between the barrier layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers or nurates thereof, mixtures of these, and copolymers with other polymers. Other examples include adducts, biuret compounds, and isocyanurates.

[0110] The content of the compound having an isocyanate 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 constituting the adhesive layer 5. This can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0111] The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

[0112] 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 %, in the resin composition constituting the adhesive layer 5. This can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0113] An example of a compound having an epoxy group is an epoxy resin. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by 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 about 50 to 2,000, more preferably about 100 to 1,000, and even more preferably about 200 to 800. In the present disclosure, the weight-average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

[0114] Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, etc. One type of epoxy resin may be used alone, or two or more types may be used in combination.

[0115] The proportion of the epoxy resin 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 constituting the adhesive layer 5. This can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0116] The polyurethane is not particularly limited, and any known polyurethane can be used. The adhesive layer 5 may be, for example, a cured product of two-component curing polyurethane.

[0117] The proportion of polyurethane in 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 constituting adhesive layer 5. This effectively improves the adhesion between barrier layer 3 and adhesive layer 5 in an atmosphere containing components that induce corrosion of the barrier layer, such as an electrolyte solution.

[0118] In addition, when the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as the main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

[0119] The thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 5 μm or less. The thickness of the adhesive layer 5 is preferably about 0.1 μm or more, or about 0.5 μm or more. The thickness of the adhesive layer 5 is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, or about 0.5 to 5 μm. More specifically, in the case of adhesives such as those exemplified for the adhesive layer 2 or a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably about 1 to 10 μm, and more preferably about 1 to 5 μm. Furthermore, when using a resin exemplified for the heat-fusible resin layer 4, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. For example, when the adhesive layer 5 is formed from an acid-modified polyolefin, the thickness of the adhesive layer 5 is preferably about 2 μm or more, more preferably 5 μm or more, and even more preferably 8 μm or more. For example, when the adhesive layer 5 is formed from an acid-modified polyolefin, the thickness of the adhesive layer 5 is preferably about 50 μm or less, more preferably 40 μm or less. For example, when the adhesive layer 5 is formed from an acid-modified polyolefin, the preferred ranges for the thickness of the adhesive layer 5 are about 2 to 50 μm, about 2 to 40 μm, about 5 to 50 μm, about 5 to 40 μm, about 8 to 50 μm, and about 8 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 the resin exemplified for the heat-fusible resin layer 4 is used, the heat-fusible resin layer 4 and the adhesive layer 5 can be formed by extrusion molding, for example.

[0120] 3. Manufacturing method for exterior materials for power storage devices The method for producing an electrical storage device packaging material is not particularly limited as long as it can produce a laminate in which the layers of the electrical storage device packaging material of the present invention are stacked, and examples include methods that include a step of producing a laminate in which, from the outside, at least a surface coating layer 6, a base layer 1, a barrier layer 3, and a thermally adhesive resin layer 4 are stacked. Specifically, the method for producing an electrical storage device packaging material of the present disclosure includes a step of producing a laminate in which, from the outside, at least a surface coating layer 6, a base layer 1, a barrier layer 3, and a thermally adhesive resin layer 4 are stacked, the surface coating layer 6 contains a resin and particles, and the hardness of the outer surface of the surface coating layer 6 measured by a nanoindentation method in a 23°C environment is 420.4 MPa or less.

[0121] An example of a method for producing an exterior packaging material for an electricity storage device of the present invention is as follows. First, a laminate (hereinafter, sometimes referred to as "laminate A") is formed in which a base 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 an adhesive used to form adhesive layer 2 is applied to base layer 1 or to barrier layer 3 whose surface has been chemically treated as necessary, by a coating method such as gravure coating or roll coating, and then dried, and then the barrier layer 3 or base layer 1 is laminated thereon, and the adhesive layer 2 is cured.

[0122] 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. 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 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 laminating this on 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 previously 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 on the barrier layer 3 of the laminate A, followed by drying or baking, and then the heat-sealable resin layer 4 previously formed into a sheet is laminated on the adhesive layer 5.

[0123] Next, a surface coating layer 6 is laminated on the surface of the base layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above-mentioned resin composition for forming the surface coating layer 6 to the surface of the base layer 1 and curing it. The order of the step of laminating the barrier layer 3 on the surface of the base layer 1 and the step of laminating the surface coating layer 6 on the surface of the base layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base layer 1, the barrier layer 3 may be formed on the surface of the base layer 1 opposite to the surface coating layer 6.

[0124] As described above, a laminate is formed which includes, from the outside, the surface coating layer 6, the base layer 1, the optional adhesive layer 2, the barrier layer 3, the optional adhesive layer 5, and the heat-sealable resin layer 4. In order to strengthen the adhesion of the optional adhesive layer 2 and the adhesive layer 5, the laminate may be further subjected to a heat treatment. Furthermore, as described above, a colored layer may be provided between the base layer 1 and the barrier layer 3.

[0125] 4. Applications of exterior materials for energy storage devices The exterior 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 exterior packaging material for an electricity storage device according to the present disclosure.

[0126] Specifically, an electricity storage device using the electricity storage device packaging material 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 in a state in which metal terminals connected to each of the positive electrode and the negative electrode protrude outward, so that a flange portion (a region where the heat-sealable resin layers contact each other) can be formed around the periphery of the electricity storage device element, and heat-sealing the heat-sealable resin layers of the flange portion to form a hermetic seal. Note that 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 inside (the surface in contact with the electricity storage device element).

[0127] The exterior material for an electricity storage device according to the present disclosure can be suitably used in electricity storage devices such as batteries (including condensers, capacitors, etc.). The exterior material for an electricity storage device according to the present disclosure may be used in either primary or secondary batteries, but is preferably used in secondary batteries. The type of secondary battery to which the exterior material for an electricity storage device according to the present disclosure is 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, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for the exterior material for an electricity storage device according to the present disclosure. [Example]

[0128] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the examples.

[0129] <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 substrate layer were laminated by dry lamination using the adhesive (a two-component urethane adhesive containing a colorant) described below, and then aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate. Both sides of the aluminum foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum foil was performed using a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m. 2 (dry mass) was applied to both sides of an aluminum foil by roll coating, and baked.

[0130] 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 an adhesive layer / heat-sealable resin layer on the barrier layer. Furthermore, Resin Composition 1 below was applied to the surface of the substrate layer of the obtained laminate to a thickness of 3 μm and cured under forming conditions in an environment of 40°C to 100°C for 3 days to form a matte surface coating layer, thereby obtaining an exterior material for an electricity storage device consisting of a laminate (total thickness 96 μm) laminated from the outside in the following order: surface coating layer (3 μm) / substrate layer (15 μm thick) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-sealable resin layer (20 μm).

[0131] [Example 2] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that in forming the surface coating layer, the following resin composition 2 was used instead of resin composition 1 to form the surface coating layer.

[0132] [Example 3] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that the surface coating layer was formed using the following resin composition 3 instead of resin composition 1.

[0133] [Example 4] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that the surface coating layer was formed using the following resin composition 4 instead of resin composition 1.

[0134] [Example 5] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that the surface coating layer was formed using the following resin composition 5 instead of resin composition 1.

[0135] [Example 6] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that the surface coating layer was formed using the following resin composition 6 instead of resin composition 1.

[0136] [Example 7] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that the surface coating layer was formed using the following resin composition 7 instead of resin composition 1.

[0137] [Example 8] An oriented nylon (ONy) film (thickness 12 μm) was prepared as the substrate layer. A stainless steel foil (SUS301 (thickness 20 μm)) was prepared as the barrier layer. Next, the barrier layer and substrate layer were laminated by dry lamination using the adhesive (a two-component urethane adhesive containing a colorant) described below, and then an aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate. Both sides of the stainless steel foil were subjected to a chemical conversion treatment. The chemical conversion treatment of the stainless steel foil was performed by applying a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid to a coating amount of chromium of 10 mg / m 2 (dry mass) was applied to both sides of a stainless steel foil by roll coating, and then baked.

[0138] Next, the barrier layer and the heat-sealable resin layer of each laminate obtained above were bonded by dry lamination using a modified olefin-based adhesive (the adhesive layer was 3 μm thick after curing), and the adhesive layer and the heat-sealable resin layer were laminated on the barrier layer. An unstretched polypropylene film (23 μm thick) was used as the heat-sealable resin layer. Furthermore, the surface of the substrate layer of the obtained laminate was coated with the following resin composition 2 to a thickness of 3 μm and cured under conditions of 40°C to 100°C for 3 days to form a matte surface coating layer. A laminate (total thickness 64 μm) was obtained, consisting of the surface coating layer (3 μm), substrate layer (12 μm thick), adhesive layer (3 μm), barrier layer (20 μm), adhesive layer (3 μm), and heat-sealable resin layer (23 μm) stacked in this order from the outside.

[0139] [Example 9] An exterior material for an electricity storage device was obtained in the same manner as in Example 8, except that the surface coating layer was formed using the following resin composition 9 instead of resin composition 2.

[0140] [Example 10] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that in forming the surface coating layer, the following resin composition 10 was used instead of resin composition 1 to form the surface coating layer.

[0141] [Comparative Example 1] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that the surface coating layer was formed using the following resin composition 8 instead of resin composition 1.

[0142] <Resin composition used to form the surface coating layer and forming conditions> (Resin Composition 1 (used in Example 1)) A resin composition containing resin (polyurethane formed from a mixture of two types of polyol compounds and an aromatic isocyanate compound), inorganic particles (silica particles, average particle size 1 μm), polystyrene organic particles (average particle size 2 μm), and an olefin wax.

[0143] (Resin Composition 2 (used in Examples 2 and 8)) A resin composition containing resin (polyurethane formed from a mixture of two types of polyol compounds and an aliphatic isocyanate compound), inorganic particles (silica particles, average particle size 1 μm), polystyrene organic particles (average particle size 2 μm), and olefin wax.

[0144] (Resin Composition 3 (used in Example 3)) A resin composition containing a resin (polyurethane formed from a mixture of two types of polyol compounds and an aromatic isocyanate compound (the blending ratio of the two types of polyol compounds was changed from that of Resin Composition 1)), inorganic particles (silica particles, average particle diameter 1 μm), polystyrene organic particles (average particle diameter 2 μm), and an olefin wax.

[0145] (Resin Composition 4 (used in Example 4)) A resin composition containing 100 parts by mass of a resin (polyurethane formed from a mixture of one type of polyol compound and an aliphatic isocyanate compound), 10 parts by mass of inorganic particles (barium sulfate particles, average particle diameter 1 μm), polystyrene-based organic particles (average particle diameter 2 μm), and an olefin-based wax.

[0146] (Resin Composition 5 (used in Example 5)) A resin composition in which the content of olefin wax in the resin composition of Example 3 is 1 / 4

[0147] (Resin Composition 6 (used in Example 6)) A resin composition in which the content of olefin wax in the resin composition of Example 3 is 1 / 8

[0148] (Resin Composition 7 (used in Example 7)) Resin composition of Example 3 containing no olefin wax

[0149] (Resin composition 8 (used in Comparative Example 1)) The same materials as in Example 1 were used, except that an aromatic isocyanate compound different from that in Example 1 was used.

[0150] (Resin Composition 9 (used in Example 9)) A resin composition containing resin (polyurethane formed from a mixture of two types of polyol compounds and an aromatic isocyanate compound (the blending ratio of the two types of polyol compounds was changed from that of Resin Composition 1)), inorganic particles (silica particles, average particle diameter 1 μm), and polystyrene-based organic particles (average particle diameter 2 μm).

[0151] (Resin Composition 10 (Used in Example 10)) A resin composition containing resin (polyurethane formed from a mixture of two types of polyol compounds and an aromatic isocyanate compound (the blending ratio of the two types of polyol compounds was changed from that of Resin Composition 1)), inorganic particles (silica particles, average particle diameter 1 μm), and polystyrene-based organic particles (average particle diameter 2 μm).

[0152] [Hardness measured by nanoindentation at 23°C] The hardness was measured using a nanoindenter (HYSITRON's "TI950 TriboIndenter"). A Berkovich indenter (TI-0039) was used as the indenter of the nanoindenter. First, in an environment of 50% relative humidity and 23°C, the indenter was applied perpendicular to the thickness direction to the surface of the surface coating layer of the electrical storage device packaging material (the surface where the surface coating layer is exposed, parallel to the thickness direction of each layer). The indenter was pressed into the surface coating layer from the surface up 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 at different measurement points was taken as the hardness. The results are shown in Table 1. The surface against which the indenter was pressed was the resin portion where the cross section of the surface coating layer was exposed, obtained by cutting the electrical storage device packaging material in the thickness direction through the center. In measuring the hardness of the surface coating layer, the indenter was pressed into a portion of the surface of the surface coating layer where no particles were present (resin portion). The measurement results were rounded to the nearest tenth. The organic particles contained in the surface coating layers of Examples 1-10 and Comparative Example 1 were the same, and the hardness of the surface coating layers of Examples 2 and 10, measured by pressing the indenter into the portion where the organic particles were present, was 496.1 MPa. Cutting was performed using a commercially available rotary microtome. The measurement results were rounded to the nearest tenth.

[0153] [Moldability] Each packaging material for an electricity storage device was cut into a rectangle with a length (MD) of 90 mm and a width (TD) of 150 mm to prepare a test sample. The MD of the packaging material for an electricity storage device corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the packaging material for an electricity storage device corresponds to the TD of the aluminum alloy foil. This test sample was placed in a 25°C environment in a rectangular molding die (female die, the surface of which had a maximum height roughness (nominal value of Rz) of 3.2 μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 1 (Reference), corner R2.0 mm, ridge R1.0 mm) with a diameter of 31.6 mm (MD) x 54.5 mm (TD) and a corresponding molding die (male die, the surface of the ridgeline had a maximum height roughness (nominal value of Rz) of 1.6 μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 1 (Reference), and the surface other than the ridgeline had a maximum height roughness (nominal value of Rz) of 1.6 μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 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. Ten test samples were cold-formed (single-stage pull-in molding) using a corner radius of 2.0 mm and a ridge radius of 1.0 mm, with a pressing pressure (surface pressure) of 0.22 MPa and a molding depth of 5 mm. The test samples were placed on a female mold with the heat-sealable resin layer facing the male mold. The clearance between the male and female molds was 0.3 mm. The matte design of each cold-formed test sample was evaluated according to the following criteria. The results are shown in Table 1. A: The matte design was well maintained even after molding, and there was no cracking or peeling of the surface coating layer. B: After molding, no cracks or peeling occurred in the surface coating layer, but gloss appeared on the surface of the surface coating layer, damaging the matte design. C: After molding, gloss appeared on the surface of the surface coating layer, damaging the matte design, and furthermore, cracks and peeling occurred in the surface coating layer.

[0154] [Table 1]

[0155] In the electrical storage device packaging materials of Examples 1-10, the surface coating layer contains a resin and particles, and the hardness of the outer surface of the surface coating layer measured by nanoindentation in an environment of 23°C is 420.4 MPa or less. The electrical storage device packaging materials of Examples 1-10 suppress the occurrence of cracking and peeling of the surface coating layer due to molding of the electrical storage device packaging materials. Furthermore, in Examples 5 and 6, in which the amount of wax added to the surface coating layer was small, the occurrence of cracking and peeling of the surface coating layer was further suppressed, and in Examples 7, 9, and 10, in which the surface coating layer did not contain wax, the occurrence of cracking and peeling of the surface coating layer was further suppressed.

[0156] As described above, the present disclosure provides the following aspects of the invention. Item 1. The device is composed of a laminate including, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer; the surface coating layer contains a resin and particles, An exterior material for an electricity storage device, wherein the hardness of the resin of the surface coating layer, measured by nanoindentation in a cross section in the thickness direction of the surface coating layer in a 23°C environment, is 420.4 MPa or less. Item 2. The exterior packaging material for an electricity storage device according to Item 1, wherein the hardness of the particles in the surface coating layer is 300.0 MPa or more when measured by nanoindentation in a 23°C environment on a cross section in the thickness direction of the surface coating layer. Item 3. The packaging material for an electricity storage device according to Item 1 or 2, further comprising an adhesive layer between the base layer and the barrier layer. Item 4. The packaging material for an electricity storage device according to Item 3, wherein the adhesive layer is colored. Item 5. The packaging material for an electricity storage device according to any one of Items 1 to 4, further comprising a colored layer between the base layer and the barrier layer. Item 6. A method for producing an exterior material for an electricity storage device, The method includes a step of obtaining a laminate in which at least a surface coating layer, a base layer, a barrier layer, and a thermally adhesive resin layer are laminated in this order from the outside, the surface coating layer contains a resin and particles, A method for producing an exterior material for an electricity storage device, wherein the hardness of the resin of the surface coating layer, measured by nanoindentation method on a cross section in the thickness direction of the surface coating layer in an environment of 23°C, is 420.4 MPa or less. Item 7. 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 5. [Explanation of symbols]

[0157] 1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-fusible resin layer 5 Adhesive layer 6 Surface coating layer 10. Exterior materials for energy storage devices

Claims

1. The laminate is composed of a surface coating layer, a base material layer, a barrier layer, and a thermally adhesive resin layer, in this order from the outside, the surface coating layer contains a resin and particles, The particles include inorganic particles, a lubricant is contained in at least one of the surface and the interior of the surface coating layer; An outer casing material for an electricity storage device, wherein the hardness of the resin of the surface coating layer is 420.4 MPa or less when measured by nanoindentation in a cross section in the thickness direction of the surface coating layer in a 23°C environment.

2. 2. The exterior material for an electricity storage device according to claim 1, wherein the lubricant is at least one selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides.

3. The packaging material for an electricity storage device according to claim 1 or 2, wherein the inorganic particles are silica.

4. The packaging material for an electricity storage device according to claim 1 or 2, wherein the inorganic particles are titanium oxide.

5. The packaging material for an electricity storage device according to claim 1 or 2, wherein the inorganic particles are kaolin.

6. the surface coating layer is formed of a two-component curing polyurethane containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound, The packaging material for an electricity storage device according to any one of claims 1 to 5, wherein the curing agent is an aromatic polyisocyanate.

7. 7. The electrical storage device packaging material according to claim 1, wherein the hardness of the resin of the surface coating layer measured by a nanoindentation method in a cross section in the thickness direction of the surface coating layer in a 23°C environment is 25.5 MPa or more.

8. The packaging material for an electricity storage device according to any one of claims 1 to 7, wherein the barrier layer contains stainless steel.

9. The packaging material for an electricity storage device according to any one of claims 1 to 8, further comprising a colored layer between the base material layer and the adhesive layer.

10. an adhesive layer is provided between the substrate layer and the barrier layer, The packaging material for an electricity storage device according to any one of claims 1 to 9, further comprising a colored layer between the adhesive layer and the barrier layer.

11. A method for producing an exterior material for an electricity storage device, comprising: The method includes a step of obtaining a laminate in which at least a surface coating layer, a base layer, a barrier layer, and a thermally adhesive resin layer are laminated in this order from the outside, the surface coating layer contains a resin and particles, The particles include inorganic particles, a lubricant is contained in at least one of the surface and the interior of the surface coating layer; A method for producing an exterior material for an electricity storage device, wherein the hardness of the resin of the surface coating layer is 420.4 MPa or less when measured by nanoindentation in a 23°C environment for a cross section in the thickness direction of the surface coating layer.

12. 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 10.

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