Outer packaging material for power storage device, and power storage device

Abstract

The invention relates to an outer packaging material for a power storage device and the power storage device. The outer packaging material for a power storage device according to the present invention comprises a base material layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer disposed between the two layers, the base material layer and the metal foil layer being bonded via an outer adhesive layer. The outer adhesive layer is formed from a cured film of a two-pack curable urethane adhesive containing a main agent containing a polyol and a polyfunctional isocyanate mixture, the content of the polyol being 50-95 mass%, and the content of the urethane adhesive being 50-95 mass%. The polyfunctional isocyanate mixture is configured to contain a mixture containing an aromatic polyfunctional isocyanate and an aliphatic polyfunctional isocyanate having an aromatic ring. With this configuration, it is possible to provide an outer packaging material for power storage devices, which has excellent yellowing resistance and satisfactory moldability, while sufficiently obtaining the adhesive strength of the outer adhesive.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 201811502064.6, whose application date is December 7, 2018 and whose invention name is “Outer packaging material for power storage device and power storage device”. Technical Field

[0002] The present invention relates to an outer packaging material for an electricity storage device, and an electricity storage device enclosed by the outer packaging material. The electricity storage device is a battery or capacitor used in portable devices such as smartphones and tablets, or a battery or capacitor used in hybrid vehicles, electric vehicles, wind power generation, solar power generation, or nighttime power storage.

[0003] It should be noted that in this specification and claims, the term "aromatic polyfunctional isocyanate" means a polyfunctional isocyanate having a chemical structural formula in which the nitrogen atom of the -NCO (isocyanate functional group) is directly bonded to a carbon atom constituting an aromatic ring (phenyl ring), and the term "aliphatic polyfunctional isocyanate having an aromatic ring" means a polyfunctional isocyanate having a chemical structural formula in which the nitrogen atom of the -NCO (isocyanate functional group) is bonded to a carbon atom constituting an aromatic ring (phenyl ring) via one or more linking groups such as methylene groups. In other words, the term "aliphatic polyfunctional isocyanate having an aromatic ring" does not include polyfunctional isocyanates having a chemical structural formula in which the nitrogen atom of the -NCO (isocyanate functional group) is directly bonded to a carbon atom constituting an aromatic ring (phenyl ring). Background Art

[0004] In recent years, with the thinning and lightening of mobile electronic devices such as smart phones and tablet terminals, as outer packaging materials for storage devices such as lithium ion secondary batteries, lithium polymer secondary batteries, lithium ion capacitors (capacitors), and electric double-layer capacitors (electric double-layer condensers) carried in the above-mentioned mobile electronic devices, laminates formed by heat-resistant resin layer / outer adhesive layer / metal foil layer / inner adhesive layer / thermo-fusible resin layer (inner sealing layer) have gradually been used to replace the previous metal cans. In addition, the power supply of electric vehicles, large power supplies for storage purposes, capacitors, etc. are also packaged using the laminates (outer packaging materials) of the above-mentioned structure. By performing embossing and deep drawing on the above-mentioned laminate, it is formed into a three-dimensional shape such as a roughly rectangular parallelepiped shape. By forming it into such a three-dimensional shape, it is possible to ensure a storage space for the main body of the storage device.

[0005] Furthermore, it is known to use an adhesive containing a polyfunctional isocyanate as an outer adhesive to prevent delamination (peeling) between the heat-resistant resin layer and the metal layer (see Patent Document 1). Patent Document 1 states that toluene diisocyanate is preferably used as the polyfunctional isocyanate.

[0006] Patent Document 1: Japanese Patent No. 4380728 Summary of the Invention

[0007] However, battery packaging materials using toluene diisocyanate as a polyfunctional isocyanate have the problem of yellowing the outer adhesive layer and poor appearance due to contact with the electrolyte in an atmosphere exposed to the electrolyte. While care can be taken during manufacturing to prevent electrolyte contact, it is difficult to prevent electrolyte adhesion to the outer packaging material during manufacturing. Therefore, a composition is required that prevents the outer adhesive from yellowing even if the electrolyte adheres to the outer packaging material.

[0008] The present invention has been made in view of the above technical background, and an object thereof is to provide an outer packaging material for a power storage device having excellent yellowing resistance, sufficient bonding strength of an outer adhesive, and good moldability, and a power storage device packaged with the outer packaging material.

[0009] Means for solving problems

[0010] To achieve the above-mentioned object, the present invention provides the following means.

[0011] [1] An outer packaging material for an electrical storage device, characterized in that the outer packaging material comprises a base material layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer disposed between the two layers, wherein:

[0012] The base material layer and the metal foil layer are bonded via an outer adhesive layer.

[0013] The outer adhesive layer is formed of a cured film of a two-component curable urethane adhesive, wherein the two-component curable urethane adhesive comprises a main component containing a polyol and a polyfunctional isocyanate mixture, wherein the content of the polyol is 50% to 95% by mass.

[0014] The polyfunctional isocyanate mixture includes a mixture of an aromatic polyfunctional isocyanate and an aliphatic polyfunctional isocyanate having an aromatic ring.

[0015] [2] The outer packaging material for a storage battery device according to the above item 1, wherein the content of the aromatic polyfunctional isocyanate in the polyfunctional isocyanate mixture is 5% by mass to 50% by mass, and the content of the aliphatic polyfunctional isocyanate having an aromatic ring in the polyfunctional isocyanate mixture is 50% by mass to 95% by mass.

[0016] [3] The outer packaging material for an electrical storage device according to item 1 or 2 above, wherein:

[0017] The polyol is a polyester polyol,

[0018] The polyester polyol comprises a dicarboxylic acid component,

[0019] The dicarboxylic acid component contains an aromatic dicarboxylic acid, and the content of the aromatic dicarboxylic acid in the dicarboxylic acid component is 40 mol % to 80 mol %.

[0020] [4] The outer packaging material for a power storage device according to any one of Items 1 to 3 above, wherein the aliphatic polyfunctional isocyanate having an aromatic ring is one or more isocyanates selected from the group consisting of xylylenediisocyanate and modified products thereof.

[0021] [5] The outer packaging material for a power storage device according to any one of the above items 1 to 4, wherein the Young's modulus of a cured film of the two-component curable urethane adhesive is 90 MPa to 400 MPa.

[0022] [6] An outer casing for a power storage device, formed from a molded body of the outer casing material for a power storage device according to any one of 1 to 5 above.

[0023] [7] An electric storage device characterized by comprising:

[0024] a power storage device main body; and

[0025] One or two outer packaging members selected from the group consisting of the outer packaging material for a power storage device according to any one of the preceding items 1 to 5 and the outer packaging case for a power storage device according to the preceding item 6,

[0026] The power storage device main body is enclosed by the outer packaging member.

[0027] Effects of the Invention

[0028] In the invention of [1], the polyfunctional isocyanate mixture is composed of a mixture containing an aromatic polyfunctional isocyanate and an aliphatic polyfunctional isocyanate having an aromatic ring. Therefore, the outer adhesive layer is less likely to yellow, the outer packaging material has excellent yellowing resistance, and the bonding strength of the outer adhesive can be sufficiently obtained, and the moldability is also good.

[0029] In the invention of [2], yellowing resistance can be further improved, moldability can be improved, and the bonding strength of the outer adhesive can be increased.

[0030] In the invention of [3], polyester polyol is used as the polyol. By making the content of the aromatic dicarboxylic acid in the above-mentioned dicarboxylic acid component 40 mol% or more, delamination (peeling) between the outer layer and the metal foil layer can be more effectively prevented, and by making the content of the aromatic dicarboxylic acid in the above-mentioned dicarboxylic acid component 80 mol% or less, the bonding strength of the outer adhesive can be more effectively ensured.

[0031] In the invention of [4], yellowing resistance can be further improved.

[0032] In the invention of [5], by making the Young's modulus of the cured film of the two-component curing urethane adhesive not less than 90 MPa, the heat resistance of the outer adhesive layer can be improved, and delamination (peeling) between the outer layer and the metal foil layer during heat sealing can be more effectively prevented. By making the above-mentioned Young's modulus not more than 400 MPa, the bonding strength of the outer adhesive can be more effectively ensured, and the high-temperature lamination strength can also be improved.

[0033] In the invention of [6], the outer adhesive layer is less likely to yellow, the outer packaging material has excellent yellowing resistance, and the bonding strength of the outer adhesive can be sufficiently ensured, thereby providing a well-molded outer packaging case for a storage battery device.

[0034] The invention of [7] can provide a power storage device that is packaged with an outer packaging member that has excellent yellowing resistance and in which the bonding strength of the outer adhesive is sufficiently ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a cross-sectional view showing one embodiment of the outer packaging material for a power storage device according to the present invention.

[0036] Figure 2 This is a cross-sectional view showing one embodiment of the power storage device according to the present invention.

[0037] Figure 3 The composition is shown in the separated state before heat sealing. Figure 2 A three-dimensional diagram of the outer packaging material (flat object) of the power storage device, the main body of the power storage device and the outer packaging case (a molded body formed into a three-dimensional shape).

[0038] Description of Reference Numerals

[0039] 1…Outer packaging materials for power storage devices

[0040] 2…base material layer (outer layer)

[0041] 3…Thermo-adhesive resin layer (inner layer)

[0042] 4…Metal foil layer

[0043] 5…Outer adhesive layer

[0044] 10…Outer packaging shell

[0045] 15…External packaging components

[0046] 30…Electricity storage device

[0047] 31…Power storage device main body DETAILED DESCRIPTION

[0048] One embodiment of the outer packaging material 1 for a power storage device of the present invention is shown in FIG. Figure 1 The outer casing material 1 for a power storage device is used for a lithium-ion secondary battery case.

[0049] The outer packaging material 1 for the above-mentioned storage battery device includes the following structure: a base material layer (outer layer) 2 is laminated and integrated on one surface of a metal foil layer 4 via an outer adhesive layer 5, and a heat-fusible resin layer (inner layer) 3 is laminated and integrated on the other surface of the above-mentioned metal foil layer 4 via an inner adhesive layer 6.

[0050] In the outer packaging material 1 for a storage battery device according to the present invention, the outer adhesive layer 5 is formed from a cured film of a two-component curable urethane adhesive. The two-component curable urethane adhesive comprises a main component containing a polyol and a polyfunctional isocyanate mixture, wherein the polyol content is 50% to 95% by mass. The polyfunctional isocyanate mixture is a mixture of an aromatic polyfunctional isocyanate and an aliphatic polyfunctional isocyanate having an aromatic ring. Therefore, the outer adhesive layer is less susceptible to yellowing, and the outer packaging material has excellent yellowing resistance. Furthermore, sufficient bonding strength of the outer adhesive can be obtained, and moldability is also good.

[0051] In the present invention, the main component of the two-component curable urethane adhesive contains a polyol, preferably containing 50% by mass or more of the polyol. By increasing the polyol content of the main component to 50% by mass or more, the adhesive strength can be further increased, effectively preventing delamination (peeling) between the outer layer 2 and the metal foil layer 4. The polyol content of the main component is more preferably 70% by mass or more, and even more preferably 90% by mass or more.

[0052] As above-mentioned polyol, there is no particular limitation, and for example polyester polyol, polyether polyol, polycaprolactone diol etc. can be enumerated.It should be noted that, in the present invention, polyester polyol comprises polyester polyol (polyester polyurethane polyol etc.) modified by carbamate, and in addition, polyether polyol comprises polyether polyol (polyether polyurethane polyol etc.) modified by carbamate.Wherein, as above-mentioned polyol, preferably use the copolymer polyester polyol using dicarboxylic acid and glycol as raw material.In the present invention, by suitably selecting the kind and composition of dicarboxylic acid and glycol as raw material, can further improve bonding strength, even when carrying out deeper molding, also can prevent interlayer peeling.

[0053] The dicarboxylic acid is not particularly limited, and examples thereof include aliphatic dicarboxylic acids and aromatic dicarboxylic acids. The aliphatic dicarboxylic acid is not particularly limited, and examples thereof include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. The aromatic dicarboxylic acid is not particularly limited, and examples thereof include phthalic acid, isophthalic acid, and terephthalic acid.

[0054] The diol is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, octanediol, 1,4-cyclohexanediol, and 2-butyl-2-ethyl-1,3-propanediol.

[0055] When a polyester polyol is used as the polyol, the polyester polyol contains a dicarboxylic acid component (including a dicarboxylic acid ester derived from a dicarboxylic acid), and the dicarboxylic acid component preferably contains an aromatic dicarboxylic acid. The content of the aromatic dicarboxylic acid in the dicarboxylic acid component is preferably 40 mol% to 80 mol%, more preferably 50 mol% to 70 mol%.

[0056] The number average molecular weight (Mn) of the polyol is preferably within a range of 8,000 to 25,000. In this case, suitable coating film strength and coating film elongation can be imparted to the outer adhesive layer 5 .

[0057] The number average molecular weight of the polyester polyol can be adjusted by chain extension using a multifunctional isocyanate. That is, if the polyester component in the main agent is connected using NCO, a polymer with a hydroxyl group at the end is generated. By adjusting the equivalent ratio of the isocyanate group to the hydroxyl group of the polyester, the number average molecular weight of the polyester polyol can be adjusted. In the present invention, it is preferred to use a substance connected in a manner such that the equivalent ratio (OH / NCO) is in the range of 1.01 to 10. In addition, as another method for adjusting the molecular weight, the adjustment of the reaction conditions of the polycondensation reaction of dicarboxylic acid and diol (such as the molar ratio of dicarboxylic acid to diol) can be cited.

[0058] As the main agent, a polyhydric alcohol, for example, can be added to the essential polyhydric alcohol. The polyhydric alcohol is not particularly limited, and examples thereof include trimethylolpropane (TMP), methylpentanediol, dimethylbutanediol, ethylene glycol, 1,4-butanediol, glycerol, and sorbitol.

[0059] The polyfunctional isocyanate mixture is a mixture of an aromatic polyfunctional isocyanate and an aliphatic polyfunctional isocyanate having an aromatic ring.

[0060] The aromatic polyfunctional isocyanate is not particularly limited, and examples thereof include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and triphenylmethane triisocyanate. Among these, the aromatic polyfunctional isocyanate is preferably one or more aromatic polyfunctional isocyanates selected from the group consisting of toluene diisocyanate, diphenylmethane diisocyanate, and polyfunctional isocyanate-modified products derived from at least one of these diisocyanates. The modification method is not particularly limited, and examples thereof include polyfunctional isocyanate-modified products obtained by polymerization reactions such as isocyanuration, carbodiimidization, and polymerization, in addition to adducts formed with polyfunctional active hydrogen compounds such as water, glycerol, and trimethylolpropane.

[0061] The aliphatic polyfunctional isocyanate having an aromatic ring is not particularly limited, and examples thereof include xylylenediisocyanate (XDI), tetramethylxylylenediisocyanate (TMXDI), and polyfunctional isocyanate modified products derived from at least one of these diisocyanates. The modification method is not particularly limited, and examples thereof include adducts formed with polyfunctional active hydrogen compounds such as water, glycerol, and trimethylolpropane, and polyfunctional isocyanate modified products obtained by polymerization reactions such as isocyanuration, carbodiimidization, and polymerization. Among these, it is preferred to use one or more isocyanates selected from the group consisting of xylylenediisocyanate and its modified products.

[0062] A preferred configuration is one in which the aromatic polyfunctional isocyanate content in the polyfunctional isocyanate mixture is 5% to 50% by mass, and the "aliphatic polyfunctional isocyanate having an aromatic ring" content in the polyfunctional isocyanate mixture is 50% to 95% by mass. This configuration further improves yellowing resistance and moldability, and also increases the bonding strength of the outer adhesive 5. A content of 5% or more of the aromatic polyfunctional isocyanate further improves moldability, while a content of 50% or less of the aromatic polyfunctional isocyanate further improves yellowing resistance. A content of 50% or more of the aliphatic polyfunctional isocyanate having an aromatic ring further improves yellowing resistance, while a content of 95% or less of the aliphatic polyfunctional isocyanate having an aromatic ring further improves moldability.

[0063] In the two-liquid curable urethane adhesive (cured film of the urethane adhesive), the content of the polyol component is set to 50% to 95% by mass. By setting the content of the polyol component to 50% by mass or more, the bonding strength of the outer adhesive can be sufficiently improved, and by setting the content of the polyol component to 95% by mass or less, sufficient sealing resistance can be ensured. In the two-liquid curable urethane adhesive, the content of the polyol component is preferably 60% to 90% by mass. Furthermore, in the two-liquid curable urethane adhesive, the content of the polyfunctional isocyanate mixture is preferably 40% to 10% by mass. Furthermore, more preferably, in the two-liquid curable urethane adhesive (cured film of the urethane adhesive), the content of the polyol component is 70% to 90% by mass, and the content of the polyfunctional isocyanate mixture is 30% to 10% by mass.

[0064] In the above-mentioned two-component curing urethane adhesive (formed by a polyol constituting the main agent and a polyfunctional isocyanate mixture as a curing agent), the isocyanate group (-NCO) of the polyfunctional isocyanate mixture is preferably blended in a ratio of 1 to 30 moles relative to 1 mole of the hydroxyl group (-OH) of the polyol. By making the molar ratio ([NCO] / [OH]) greater than 1, a sufficient curing reaction can be carried out, and suitable coating film strength and heat resistance can be obtained. In addition, by making the molar ratio ([NCO] / [OH]) less than 30, the reaction with functional groups other than the polyol will not proceed excessively, and suitable coating film strength and suitable elongation can be obtained. Among them, the molar ratio ([NCO] / [OH]) of the hydroxyl group of the polyol to the isocyanate group of the polyfunctional isocyanate mixture is particularly preferably in the range of 2 to 26.

[0065] In addition to the above-mentioned components, various known additives such as a reaction catalyst used in the urethanization and chain extension of the polyester polyol and the urethane curing reaction of the two-component curable urethane adhesive, a coupling agent for improving adhesion, an epoxy resin, an acrylic resin, a defoaming agent, a leveling agent, an ultraviolet absorber, and an antioxidant may be added to the main agent or the curing agent as needed.

[0066] The Young's modulus of the cured film of the two-component curable urethane adhesive is preferably 90 MPa to 400 MPa. By setting the Young's modulus of the cured film to 90 MPa or higher, the heat resistance of the outer adhesive layer 5 can be improved, effectively preventing delamination (peeling) between the outer layer 2 and the metal foil layer 4 during heat sealing. By setting the Young's modulus of the cured film to 400 MPa or lower, the bonding strength of the outer adhesive can be more effectively ensured, thereby also improving the high-temperature lamination strength. The Young's modulus of the cured film of the two-component curable urethane adhesive is more preferably 140 MPa to 300 MPa.

[0067] The thickness of the outer adhesive layer 5 is preferably set to 1 μm to 5 μm. In particular, from the viewpoint of thinning and reducing the weight of the outer packaging material, the thickness of the outer adhesive layer 5 is particularly preferably set to 1 μm to 3 μm.

[0068] In the present invention, the substrate layer (outer layer) 2 is preferably formed from a heat-resistant resin layer. The heat-resistant resin constituting the heat-resistant resin layer 2 is preferably one that does not melt at the heat-sealing temperature used when heat-sealing the outer packaging material 1. The heat-resistant resin preferably has a melting point that is at least 10°C higher than the melting point of the heat-fusible resin layer 3 (the melting point of the layer with the highest melting point when the heat-fusible resin layer is formed from multiple layers), and particularly preferably has a melting point that is at least 20°C higher than the melting point of the heat-fusible resin layer 3 (the melting point of the layer with the highest melting point when the heat-fusible resin layer is formed from multiple layers).

[0069] As the above-mentioned heat-resistant resin layer (outer layer) 2, there is no particular limitation, and polyamide films such as nylon films, polyester films, etc. can be cited, and stretched films of these films can be preferably used. Among them, as the above-mentioned heat-resistant resin layer 2, biaxially stretched polyamide films such as biaxially stretched nylon films, biaxially stretched polybutylene terephthalate (PBT) films, biaxially stretched polyethylene terephthalate (PET) films, or biaxially stretched polyethylene naphthalate (PEN) films are particularly preferably used. As the above-mentioned nylon film, there is no particular limitation, and nylon 6 film, nylon 6,6 film, nylon MXD film, etc. can be cited. It should be noted that the above-mentioned heat-resistant resin layer 2 can be formed by a single layer, or, for example, can be formed by a multilayer (including a multilayer of PET film / nylon film, etc.) comprising a polyester film / polyamide film.

[0070] The thickness of the heat-resistant resin layer (outer layer) 2 is preferably 2 to 50 μm. When using a polyester film, the thickness is preferably 2 to 50 μm, and when using a nylon film, the thickness is preferably 7 to 50 μm. Setting the thickness above the preferred lower limit ensures sufficient strength for use as a packaging material, while setting the thickness below the preferred upper limit reduces stress during forming processes such as bulging and drawing, thereby improving formability.

[0071] The heat-fusible resin layer (inner layer) 3 plays the role of imparting excellent chemical resistance to highly corrosive electrolytes used in lithium-ion secondary batteries and the like, and imparting heat-sealability to the outer packaging material.

[0072] The heat-fusible resin layer 3 is not particularly limited, but is preferably a heat-fusible resin unstretched film layer. The heat-fusible resin layer 3 is not particularly limited, but is preferably composed of an unstretched film made of at least one heat-fusible resin selected from polyethylene, polypropylene, olefin copolymers, their acid-modified forms, and ionomers. The heat-fusible resin layer 3 may be a single layer or multiple layers.

[0073] The thickness of the heat-fusible resin layer 3 is preferably set to 10 μm to 80 μm. A thickness of 10 μm or greater can effectively prevent the formation of pinholes, while a thickness of 80 μm or less can reduce the amount of resin used, thereby reducing costs. The thickness of the heat-fusible resin layer 3 is particularly preferably set to 25 μm to 50 μm.

[0074] The heat-fusible resin layer 3 may contain a lubricant. The lubricant is not particularly limited, but fatty acid amides are preferably used. The fatty acid amides are not particularly limited, and examples thereof include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, hydroxymethylamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides.

[0075] The metal foil layer 4 is responsible for imparting gas barrier properties (preventing the intrusion of oxygen and moisture) to the outer packaging material 1. The metal foil layer 4 is not particularly limited, and examples thereof include aluminum foil, SUS foil (stainless steel foil), copper foil, nickel foil, etc., with aluminum foil being generally used. The thickness of the metal foil layer 4 is preferably 5 μm to 50 μm. By being 5 μm or more, pinholes can be prevented from being generated during rolling when the metal foil is manufactured, and by being 50 μm or less, stress during forming such as embossing and deep drawing can be reduced, thereby improving formability. Among them, the thickness of the metal foil layer 4 is particularly preferably 10 μm to 30 μm.

[0076] For the metal foil layer 4, it is preferred to subject at least the inner surface (the surface on the second adhesive layer 6 side) to a chemical conversion treatment. By subjecting the metal foil layer 4 to such a chemical conversion treatment, corrosion of the metal foil surface caused by the contents (electrolyte of the battery, etc.) can be fully prevented. For example, the metal foil can be subjected to a chemical conversion treatment by performing the following treatment. That is, for example, by applying any of the following aqueous solutions 1) to 3) to the surface of the degreased metal foil and then drying it, a chemical conversion treatment is performed:

[0077] 1) An aqueous solution of a mixture comprising:

[0078] Phosphoric acid;

[0079] chromic acid; and

[0080] at least one compound selected from the group consisting of metal salts of fluorides and non-metal salts of fluorides,

[0081] 2) an aqueous solution of a mixture comprising:

[0082] Phosphoric acid;

[0083] At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins; and

[0084] at least one compound selected from the group consisting of chromic acid and chromium (III) salts,

[0085] 3) an aqueous solution of a mixture comprising:

[0086] Phosphoric acid;

[0087] At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins;

[0088] At least one compound selected from the group consisting of chromic acid and chromium (III) salts; and

[0089] At least one compound selected from the group consisting of metal salts of fluorides and non-metal salts of fluorides.

[0090] The chemical conversion film preferably has a chromium deposition amount (per surface) of 0.1 mg / m 2 ~50 mg / m 2 , particularly preferably 2 mg / m 2 ~20 mg / m 2 .

[0091] The inner adhesive layer 6 is not particularly limited; for example, the materials exemplified for the inner adhesive layer 5 may be used. A polyolefin-based adhesive, which exhibits minimal swelling due to the electrolyte, is preferably used. The thickness of the inner adhesive layer 6 is preferably set to 1 μm to 5 μm. In particular, from the perspective of thinner and lighter outer packaging materials, the thickness of the inner adhesive layer 6 is particularly preferably set to 1 μm to 3 μm.

[0092] By forming the outer packaging material 1 for a storage battery device of the present invention (deep drawing, embossing, etc.), an outer packaging case (battery case, etc.) 10 (see Figure 3 It should be noted that the outer packaging material 1 of the present invention can also be used directly without being formed (see Figure 3 ).

[0093] One embodiment of an electricity storage device 30 formed using the outer packaging material 1 for an electricity storage device of the present invention is shown in FIG. Figure 2 The power storage device 30 is a lithium ion secondary battery. Figure 2 、 3As shown, the outer packaging member 15 is composed of an outer packaging shell 10 obtained by molding the outer packaging material 1, and a planar outer packaging material 1. Then, the main body of the storage device (electrochemical element, etc.) 31 of a roughly rectangular parallelepiped shape is accommodated in the storage recess of the outer packaging shell 10 obtained by molding the outer packaging material 1 of the present invention, and the outer packaging material 1 of the present invention is arranged above the main body 31 of the storage device without being molded, so that the heat-fusible resin layer 3 side is the inner side (lower side), and the peripheral edge portion of the heat-fusible resin layer 3 of the planar outer packaging material 1 is sealed and joined to the heat-fusible resin layer 3 of the flange portion (sealing peripheral edge portion) 29 of the outer packaging shell 10 by heat sealing, thereby constituting the storage device 30 of the present invention (see Figure 2 、 3 It should be noted that the inner surface of the storage recess of the outer packaging shell 10 is the heat-fusible resin layer 3, and the outer surface of the storage recess is the base material layer (outer layer) 2 (see Figure 3 ).

[0094] Figure 2 In the figure, 39 denotes a heat-sealed portion formed by joining (welding) the peripheral edge of the outer packaging material 1 to the flange (sealing peripheral edge) 29 of the outer packaging case 10. It should be noted that in the above-mentioned power storage device 30, the tip end of the tab connected to the power storage device body 31 is led out of the outer packaging member 15 and is omitted in the figure.

[0095] The power storage device main body 31 is not particularly limited, and examples thereof include a battery main body, a capacitor main body, and a capacitor main body.

[0096] The width of the heat-sealed portion 39 is preferably set to 0.5 mm or more. By setting the width to 0.5 mm or more, reliable sealing can be achieved. The width of the heat-sealed portion 39 is preferably set to 3 mm to 15 mm.

[0097] It should be noted that, in the above embodiment, the outer packaging member 15 is a structure formed by the outer packaging shell 10 obtained by molding the outer packaging material 1 and the planar outer packaging material 1 (see Figure 2 、 3 ), but is not particularly limited to such a combination. For example, the outer packaging member 15 can be a structure formed by a pair of planar outer packaging materials 1, or can be a structure formed by a pair of outer packaging shells 10.

[0098] Example

[0099] Hereinafter, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

[0100] <Example 1>

[0101] A polyester polyol solution, serving as the main component of a two-component curable urethane adhesive, was prepared. 30 parts by mole of neopentyl glycol, 30 parts by mole of ethylene glycol, and 40 parts by mole of 1,6-hexanediol were melted at 80°C and, while stirring, polycondensed with a dicarboxylic acid mixture (containing 40 parts by mole of adipic acid as an aliphatic dicarboxylic acid and 60 parts by mole of isophthalic acid as an aromatic dicarboxylic acid) at 210°C for 20 hours to obtain a polyester polyol as the main component. The number average molecular weight (Mn) of this polyester polyol was 15,000. 60 parts by mass of ethyl acetate was added to 40 parts by mass of the polyester polyol (main component) obtained above and uniformly dissolved to obtain a polyester polyol solution with a solid content of 40% by mass and a hydroxyl value of 3.0 mgKOH / g (solution value).

[0102] To 80 parts by mass of this polyester polyol solution were added 6 parts by mass of a polyisocyanate solution of a toluene diisocyanate (TDI) isocyanurate (NCO content of 7.6% by mass, solids content of 50% by mass) as a curing agent and 14 parts by mass of a polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane (NCO content of 11.9% by mass, solids content of 75% by mass) as a curing agent, and stirred to produce a two-component curable urethane adhesive. The polyol content in the solids (in the outer adhesive layer) of this two-component curable urethane adhesive was 70.3% by mass. Furthermore, the solids content of the aromatic polyfunctional isocyanate in the total curing agent solids of this two-component curable urethane adhesive was 22.2% by mass, and the solids content of the "aliphatic polyfunctional isocyanate having an aromatic ring" in the total curing agent solids was 77.8% by mass.

[0103] Next, a chemical conversion treatment solution containing polyacrylic acid, a trivalent chromium compound, water, and an alcohol was applied to both surfaces of a 35 μm thick aluminum foil (A8079 aluminum foil specified in JIS H4160) and dried at 150°C to prepare aluminum foil having chemical conversion coatings formed on both surfaces. The amount of chromium deposited on each surface of the chemical conversion coating was 5 mg / m². 2 .

[0104] Next, a coating was applied to one side of the aluminum foil having the chemical conversion coating formed on both sides so that the coating amount after drying would be 3.5 g / m 2The above-mentioned two-component curing urethane adhesive was applied in a manner and dried to form an outer adhesive layer 5. A biaxially stretched polyamide film (base material layer) 2 with a thickness of 15 μm was attached to the surface of the outer adhesive layer 5. A polyacrylic acid adhesive was applied to the other side of the above-mentioned aluminum foil 4 and dried to form an inner adhesive layer 6. An unstretched polypropylene film (thermo-fusible resin layer) 3 with a thickness of 30 μm was attached to the surface of the inner adhesive layer 6. The laminate was placed in an environment of 40°C for 9 days (for aging), thereby obtaining Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0105] <Example 2>

[0106] The same procedure as in Example 1 was repeated except that 6 parts by mass of a polyisocyanate solution of isocyanurate (7.5% by mass) of diphenylmethane diisocyanate (MDI) (NCO content: 7.5% by mass, solid content: 50% by mass) of polyisocyanate solution of isocyanurate (50% by mass) of toluene diisocyanate (TDI) in Example 1 (see Table 1) was used as a curing agent to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0107] <Example 3>

[0108] The same procedures as in Example 1 were carried out except that 3 parts by mass of a toluene diisocyanate (TDI) isocyanurate multifunctional polyisocyanate solution (NCO content: 7.6% by mass, solid content: 50% by mass) and 3 parts by mass of a diphenylmethane diisocyanate (MDI) isocyanurate multifunctional polyisocyanate solution (NCO content: 7.5% by mass, solid content: 50% by mass) were used as curing agents instead of 6 parts by mass of the toluene diisocyanate (TDI) isocyanurate multifunctional polyisocyanate solution of Example 1 (see Table 1) to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0109] <Example 4>

[0110] The same procedure as in Example 1 was repeated except that 4 parts by mass of a polyisocyanate solution of isocyanurate of tolylene diisocyanate (TDI) (NCO content of 7.6 mass%, solid content of 50 mass%) and 16 parts by mass of a polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane (NCO content of 11.9 mass%, solid content of 75 mass%) as a curing agent were added instead of 6 parts by mass of the polyisocyanate solution of isocyanurate of tolylene diisocyanate (TDI) and 14 parts by mass of the polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane in Example 1 (see Table 1) and stirred to obtain a two-component curable urethane adhesive. Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0111] <Example 5>

[0112] The same procedure as in Example 1 was repeated except that 8 parts by mass of a polyisocyanate solution of isocyanurate of tolylene diisocyanate (TDI) (NCO content of 7.6 mass%, solid content of 50 mass%) and 12 parts by mass of a polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane (NCO content of 11.9 mass%, solid content of 75 mass%) as a curing agent were added instead of 6 parts by mass of the polyisocyanate solution of isocyanurate of tolylene diisocyanate (TDI) and 14 parts by mass of the polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane in Example 1 (see Table 1) and stirred to obtain a two-component curable urethane adhesive. Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0113] <Example 6>

[0114] The same procedure as in Example 1 was repeated except that 10 parts by mass of a polyisocyanate solution of isocyanurate of tolylene diisocyanate (TDI) (NCO content of 7.6 mass%, solid content of 50 mass%) and 10 parts by mass of a polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane (NCO content of 11.9 mass%, solid content of 75 mass%) as a curing agent were added instead of 6 parts by mass of the polyisocyanate solution of isocyanurate of tolylene diisocyanate (TDI) and 14 parts by mass of the polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane in Example 1 (see Table 1) and stirred to obtain a two-component curable urethane adhesive. Figure 1An outer packaging material 1 for an electric storage device having the structure shown.

[0115] <Example 7>

[0116] The same operation as in Example 1 was carried out except that a dicarboxylic acid mixture containing 65 parts by mole of adipic acid as an aliphatic dicarboxylic acid and 35 parts by mole of isophthalic acid as an aromatic dicarboxylic acid (see Table 1) was used as the dicarboxylic acid mixture to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0117] <Example 8>

[0118] The same operation as in Example 1 was carried out except that a dicarboxylic acid mixture containing 55 parts by mole of adipic acid as an aliphatic dicarboxylic acid and 45 parts by mole of isophthalic acid as an aromatic dicarboxylic acid (see Table 1) was used as the dicarboxylic acid mixture to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0119] <Example 9>

[0120] The same operation as in Example 1 was carried out except that a dicarboxylic acid mixture containing 20 parts by mole of adipic acid as an aliphatic dicarboxylic acid and 80 parts by mole of isophthalic acid as an aromatic dicarboxylic acid (see Table 1) was used as the dicarboxylic acid mixture to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0121] <Example 10>

[0122] The same operation as in Example 1 was carried out except that a dicarboxylic acid mixture containing 15 parts by mole of adipic acid as an aliphatic dicarboxylic acid and 85 parts by mole of isophthalic acid as an aromatic dicarboxylic acid (see Table 1) was used as the dicarboxylic acid mixture to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0123] <Example 11>

[0124] The same operation as in Example 1 was carried out except that a dicarboxylic acid mixture containing 10 parts by mole of adipic acid as an aliphatic dicarboxylic acid and 90 parts by mole of isophthalic acid as an aromatic dicarboxylic acid (see Table 1) was used as the dicarboxylic acid mixture to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0125] <Example 12>

[0126] The same procedure as in Example 1 was performed except that the mixing ratio of the main agent (solution) / curing agent (solution) in the two-component curing urethane adhesive was changed to main agent (solution) / curing agent (solution) = 5 parts by mass / 35 parts by mass (see Table 1). Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0127] <Example 13>

[0128] The same procedure as in Example 1 was followed except that the mixing ratio of the main component (solution) / curing agent (solution) in the two-component curing urethane adhesive was changed to main component (solution) / curing agent (solution) = 70 parts by mass / 30 parts by mass (see Table 1). Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0129] <Example 14>

[0130] The same procedure as in Example 1 was performed except that the mixing ratio of the main agent (solution) / curing agent (solution) in the two-component curing urethane adhesive was changed to main agent (solution) / curing agent (solution) = 90 parts by mass / 10 parts by mass (see Table 1). Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0131] <Example 15>

[0132] The same procedure as in Example 1 was repeated except that 80 parts by mass of the following polyether polyurethane polyol solution (referred to as "polyol O" in Table 1) was used as the main agent (solution) instead of 80 parts by mass of the polyester polyol solution of Example 1 (see Table 1) to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0133] To prepare a polyether polyurethane polyol solution, 500 parts by mass of polytetramethylene ether glycol (hydroxyl value: 112 mgKOH / g) and 82.2 parts by mass of toluene diisocyanate as a polyether polyol were added to a reaction vessel, and the mixture was reacted at 100°C for 7 hours while being stirred. After the reaction was completed, 388.1 parts by mass of ethyl acetate was further added to obtain a polyether polyurethane polyol solution (solid content: 40% by mass, number average molecular weight of the polyether polyurethane polyol: 14,500, hydroxyl value: 3.1 mgKOH / g (solution value)).

[0134] <Example 16>

[0135] The same procedure as in Example 1 was repeated except that 80 parts by mass of a polyester polyurethane polyol solution (referred to as "polyol M" in Table 1) was used as the main agent (solution) instead of 80 parts by mass of the polyester polyol solution of Example 1 (see Table 1) to obtain Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0136] To prepare the polyester polyurethane polyol solution, a polyester polyol was first prepared. 30 parts by mole of neopentyl glycol, 30 parts by mole of ethylene glycol, and 40 parts by mole of 1,6-hexanediol were mixed and melted at 80°C. The mixture was then subjected to a polycondensation reaction with a dicarboxylic acid mixture (comprising 40 parts by mole of adipic acid as an aliphatic dicarboxylic acid and 60 parts by mole of isophthalic acid as an aromatic dicarboxylic acid) at 210°C for 20 hours while stirring, yielding a polyester polyol with a hydroxyl value of 56 mgKOH / g and an acid value of 0.4 mgKOH / g. Next, 500 parts by mass of the polyester polyol obtained above and 39.2 parts by mass of toluene diisocyanate were added to a reaction vessel and reacted at 100°C for 7 hours while stirring. After the reaction was completed, 359.4 parts by mass of ethyl acetate was added to yield a polyester polyurethane polyol solution (solids content 40% by mass, number average molecular weight of 14,700, and hydroxyl value of 3.1 mgKOH / g (solution value)).

[0137] <Example 17>

[0138] The same procedures as in Example 1 were repeated except that 14 parts by mass of a polyisocyanate solution of an adduct of tetramethylxylylenediisocyanate (TMXDI) and trimethylolpropane (NCO content: 10.2% by mass, solid content: 75% by mass) was added as a curing agent (aliphatic polyfunctional isocyanate having an aromatic ring) in place of 14 parts by mass of the polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane in Example 1 (see Table 1) and stirring was performed to obtain a two-component curable urethane adhesive. Figure 1 An outer packaging material 1 for an electric storage device having the structure shown.

[0139] Comparative Example 1

[0140] A packaging material for a power storage device was obtained in the same manner as in Example 1, except that 20 parts by mass of a polyisocyanate solution of diphenylmethane diisocyanate (MDI) (NCO content: 7.5% by mass, solid content: 50% by mass) was used as a curing agent instead of 6 parts by mass of a polyisocyanate solution of toluene diisocyanate (TDI) and 14 parts by mass of a polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane (see Table 1).

[0141] Comparative Example 2

[0142] A packaging material for a power storage device was obtained in the same manner as in Example 1, except that 20 parts by mass of a polyisocyanate solution of tolylene diisocyanate (TDI) isocyanurate (NCO content 7.6% by mass, solid content 50% by mass) was used as a curing agent instead of 6 parts by mass of the polyisocyanate solution of tolylene diisocyanate (TDI) isocyanurate and 14 parts by mass of the polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane (see Table 1).

[0143] Comparative Example 3

[0144] A packaging material for a power storage device was obtained in the same manner as in Example 1, except that 20 parts by mass of a polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane (NCO content: 11.9% by mass, solid content: 75% by mass) was used as a curing agent instead of 6 parts by mass of the isocyanurate polyfunctional polyisocyanate solution of toluene diisocyanate (TDI) and 14 parts by mass of the polyisocyanate solution of an adduct of xylylenediisocyanate (XDI) and trimethylolpropane in Example 1 (see Table 1).

[0145] The Young's modulus of the cured films of the two-component curable urethane adhesives (outer adhesives) used in Examples 1 to 17 and Comparative Examples 1 to 3 is shown in Table 1. These Young's moduli were measured in accordance with JIS K7127-1999 (Tensile testing methods for plastic films). Specifically, each outer adhesive was applied to a glass plate at a thickness of 50 μm and then heat-cured at 40°C for 11 days to thermally cure the outer adhesive, yielding a cured product having a thickness of 46 μm. The cured product was peeled from the glass plate and cut into test pieces measuring 150 mm in length, 10 mm in width, and 46 mm in thickness. Tensile tests were conducted using a Shimadzu Access Corporation STROGRAPH (tensile testing apparatus) (AGS-5kNX) with an initial distance between clamps of 100 mm and a distance between markings of 50 mm at a tensile speed of 200 mm / min to determine the Young's modulus (MPa).

[0146]

[0147] [Table 2]

[0148]

[0149] Each of the outer packaging materials for a power storage device obtained as described above was evaluated according to the following evaluation method. The results are shown in Table 2.

[0150] <Yellowing resistance evaluation method>

[0151] Lithium hexafluorophosphate (LiPF6) was dissolved at a concentration of 1000 ppm in a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) in equal volumes to prepare an electrolyte. A storage device packaging material was immersed in this electrolyte and stored at 45°C for 24 hours. The packaging material was then removed, washed with water, and dried. The dried packaging material was then measured for the outer layer using a Konica Minolta CM-2500 colorimeter. The b value was used as the criterion for determining the degree of yellowing, and evaluation was performed according to the following criteria. A larger b value indicates a more intense yellow color.

[0152] (Judgment Criteria)

[0153] “◎”…b value is 1.0 or less (pass)

[0154] “○”…b value is greater than 1.0 and less than 2.0 (pass)

[0155] “×”…b value is greater than 2.0.

[0156] <Moldability Evaluation Method>

[0157] Using a straight die with no restrictions on forming depth, a single-stage deep drawing process was performed on the outer packaging material under the following forming conditions. Formability was evaluated for each forming depth (9.0 mm, 8.5 mm, 8.0 mm, 7.5 mm, 7.0 mm, 6.5 mm, 6.0 mm, 5.5 mm, 5.0 mm, 4.5 mm, 4.0 mm, 3.5 mm, 3.0 mm, 2.5 mm, and 2.0 mm). The maximum forming depth (mm) that allowed for satisfactory forming without any pinholes in the corners was determined, and formability was evaluated based on the following criteria. The presence of pinholes can be determined by visually observing the presence of light passing through the pinholes.

[0158] (Molding conditions)

[0159] Forming die… Punch: 33.3mm×53.9mm, Die: 80mm×120mm, Corner R: 2mm, Punch R: 1.3mm, Die R: 1mm

[0160] Anti-wrinkle pressure: Gauge pressure: 0.475MPa, actual pressure (calculated value): 0.7MPa

[0161] Material: SC (carbon steel), only the punch R is chrome-plated.

[0162] (Judgment Criteria)

[0163] "◎" ... Maximum molding depth without pinholes or cracks is 7.0 mm or more (qualified)

[0164] "○" ... Maximum molding depth without pinholes or cracks is 5.0 mm or more and less than 7.0 mm (pass)

[0165] “×”…The maximum forming depth without pinholes or cracks is less than 5.0 mm.

[0166] <Hot lamination strength evaluation method>

[0167] A test piece measuring 15 mm wide and 150 mm long was cut from the obtained outer packaging material for a storage battery device. The test piece was held at a temperature of 120°C for 1 minute. Then, the peel strength when a T-shaped peel occurred between the outer layer 2 and the metal foil layer 4 at a tensile speed of 100 mm / min was measured directly at 120°C using a STROGRAPH (tensile testing apparatus) (AGS-5kNX) manufactured by Shimadzu Access Corporation in accordance with JIS K6854-3 (1999). This was used as the thermal lamination strength (N / 15 mm width) and evaluated based on the following criteria.

[0168] (Judgment Criteria)

[0169] “◎”…Hot lamination strength is “2.0N / 15mm width” or above (passed)

[0170] "○" ... Thermal lamination strength is "1.5N / 15mm width" or more and less than "2.0N / 15mm width" (pass)

[0171] “△”…The thermal lamination strength is “1.0N / 15mm width” or more and less than “1.5N / 15mm width” (passed)

[0172] “×”…The thermal lamination strength is less than “1.0N / 15mm width”.

[0173] <Evaluation method for sealing resistance>

[0174] After deep drawing the outer packaging material in a single step to a depth of 5.0 mm using a linear die with no depth restrictions, the pair of molded products were then superimposed with their inner layers in contact at their peripheries. Heat-sealing was performed using a TESTER SANGYOCo., Ltd. heat sealer (TP-701-A) at a temperature of 170°C, a pressure of 0.2 MPa (as indicated on the instrument), and a sealing time of 6 seconds using single-sided heating. The appearance of the heat-sealed products was visually inspected to determine the presence and length of any warping or delamination (peeling) between the outer layer and the metal foil layer. Seal resistance was evaluated based on the following criteria.

[0175] (Judgment Criteria)

[0176] “◎”…No warping or delamination (passed)

[0177] "○" ... The length of the warped part and the delamination part is greater than 0mm and less than 2mm (pass)

[0178] "△" ... The length of the warped part and the delamination part is greater than 2mm and less than 4mm (qualified)

[0179] “×”…The length of the raised or delaminated area is greater than 4mm.

[0180] As can be seen from the table, the packaging materials for power storage devices of Examples 1 to 17 of the present invention are excellent in yellowing resistance, can ensure good moldability, can obtain sufficient hot lamination strength, and are also good in sealing resistance.

[0181] In contrast, Comparative Examples 1 and 2, which used aromatic polyfunctional isocyanates alone as curing agents, exhibited poor yellowing resistance. Furthermore, Comparative Example 3, which used aromatic polyfunctional isocyanates alone as curing agents, exhibited poor moldability.

[0182] Industrial Application Possibilities

[0183] The outer packaging material for a power storage device according to the present invention can be used as an outer packaging material for various power storage devices, and specific examples thereof include:

[0184] ·Electrical storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.);

[0185] Lithium-ion capacitors;

[0186] Double layer capacitance; etc.

[0187] Furthermore, the power storage device according to the present invention includes not only the power storage devices exemplified above but also all-solid-state batteries.

[0188] This application claims the benefit of priority from Japanese Patent Application No. 2017-250366, filed on December 27, 2017, the disclosure of which constitutes a part of this application.

[0189] The terms and descriptions used herein are for explaining the embodiments of the present invention and are not intended to limit the present invention. The present invention allows for any design changes as long as they do not exceed the spirit of the present invention within the scope of the claims.

Claims

1. An outer packaging material for an electrical storage device, characterized in that: The outer packaging material for a power storage device comprises a base material layer as an outer layer, a heat-fusible resin layer as an inner layer, and a metal foil layer disposed between the two layers, wherein The base material layer and the metal foil layer are bonded together via an outer adhesive layer. The outer adhesive layer is formed of a cured film of a two-component curable urethane adhesive, wherein the two-component curable urethane adhesive comprises a main component containing a polyol and a polyfunctional isocyanate mixture, wherein the content of the polyol is 50% to 95% by mass. The polyfunctional isocyanate mixture is a mixture consisting only of aromatic polyfunctional isocyanate and aliphatic polyfunctional isocyanate having an aromatic ring. The content of the aromatic polyfunctional isocyanate in the polyfunctional isocyanate mixture is 14.3% by mass to 40% by mass, and the content of the aliphatic polyfunctional isocyanate having an aromatic ring in the polyfunctional isocyanate mixture is 60% by mass to 85.7% by mass.

2. The outer packaging material for a power storage device according to claim 1, wherein The polyol is a polyester polyol, The polyester polyol comprises a dicarboxylic acid component, The dicarboxylic acid component contains an aromatic dicarboxylic acid, and the content of the aromatic dicarboxylic acid in the dicarboxylic acid component is 40 mol % to 80 mol %.

3. The outer packaging material for a power storage device according to claim 1 or 2, wherein The aliphatic polyfunctional isocyanate having an aromatic ring is one or more isocyanates selected from the group consisting of xylylenediisocyanate and modified products thereof.

4. The outer packaging material for an electrical storage device according to claim 1 or 2, wherein The Young's modulus of a cured film of the two-component curable urethane adhesive is 90 MPa to 400 MPa. 5 . An outer casing for an electrical storage device, formed from the molded body of the outer casing material for an electrical storage device according to claim 1 .

6. An electric storage device, characterized in that have: a power storage device main body; and One or two outer packaging members selected from the group consisting of the outer packaging material for an electrical storage device according to any one of claims 1 to 4 and the outer packaging case for an electrical storage device according to claim 5, The power storage device main body is enclosed by the outer packaging member.

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