JP7532776B2 - Exterior material for power storage device and power storage device using same - Google Patents

Description

This disclosure relates to an exterior material for a power storage device and a power storage device using the same.

Known examples of power storage devices include secondary batteries such as lithium ion batteries, nickel metal hydride batteries, and lead acid batteries, as well as electrochemical capacitors such as electric double layer capacitors. There is a demand for further miniaturization of power storage devices due to the miniaturization of portable devices and restrictions on installation space, and lithium ion batteries, which have a high energy density, are attracting attention. Traditionally, metal cans have been used as the exterior material for lithium ion batteries, but multilayer films, which are lightweight, have high heat dissipation properties, and can be produced at low cost, are now being used.

A lithium-ion battery that uses the above multilayer film as an exterior material is called a laminated lithium-ion battery. The exterior material covers the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.) and prevents moisture from penetrating into the battery. A laminated lithium-ion battery is manufactured, for example, by forming a recess in part of the exterior material by cold forming, housing the battery contents in the recess, folding back the remaining part of the exterior material, and heat sealing the edges (see, for example, Patent Document 1).

JP 2013-101765 A

Meanwhile, research and development is being conducted on power storage devices known as all-solid-state batteries as the next generation of lithium-ion batteries. All-solid-state batteries are characterized by using a solid electrolyte rather than an organic electrolyte as the electrolyte. Lithium-ion batteries cannot be used at temperatures higher than the boiling point of the electrolyte (approximately 80°C), whereas all-solid-state batteries can be used at temperatures above 100°C, and the conductivity of lithium ions can be increased by operating them under high temperature conditions (for example, 100-150°C).

However, when manufacturing a laminate-type all-solid-state battery using the above-mentioned multilayer film as an exterior material, if the heat resistance of the exterior material is insufficient, the interlayer adhesion (adhesion between layers fused by heat sealing) cannot be ensured in a high-temperature environment after heat sealing, and the heat seal strength may decrease, resulting in a decrease in the sealability of the package of the all-solid-state battery.

This disclosure has been made in consideration of the above problems, and aims to provide an exterior material for a storage battery device that can ensure excellent heat seal strength even in a high-temperature environment, and a storage battery device using the same.

To achieve the above object, the present disclosure provides an exterior material for a storage battery device that includes at least a base layer, a barrier layer, and a sealant layer in this order, in which the sealant layer includes component (A): a compound that contains a polyolefin unit and has a melting point of 175°C or higher or a glass transition temperature of 75°C or higher, and component (B): at least one resin selected from the group consisting of polyethylene-based resins and polypropylene-based resins.

The above-mentioned exterior packaging material for a storage battery device has a sealant layer of the above-mentioned configuration, and therefore can ensure excellent heat seal strength even in a high-temperature environment. This is because the use of the above-mentioned (A) component and the above-mentioned (B) component in combination ensures good heat sealability with the (B) component, while the (A) component can impart excellent heat resistance to the sealant layer. Therefore, the above-mentioned exterior packaging material can obtain sufficient heat seal strength at a heat seal temperature of about 200°C, and can maintain good interlayer adhesion (adhesion between the sealant layers fused by heat sealing) even in a high-temperature environment (for example, about 150°C) after heat sealing, ensuring excellent heat seal strength.

In the exterior material for a storage battery device, the component (A) may contain a polyamide/polyolefin graft copolymer, and the content of the component (A) in the sealant layer may be 5 to 100 parts by mass per 100 parts by mass of the component (B). In this case, more sufficient heat seal strength can be obtained at a heat seal temperature of about 200°C, and excellent heat seal strength can be more sufficiently ensured even in a high-temperature environment.

In the exterior material for a storage battery device, the (A) component includes a polyamide/polyethylene graft copolymer, the (B) component includes the polypropylene-based resin, and the sealant layer may further include the (C) component: a compatibilizer having a portion compatible with the polyamide/polyethylene graft copolymer and a portion compatible with the polypropylene-based resin. By including the (A) component in a polyamide/polyethylene graft copolymer and the (B) component in a polypropylene-based resin, the heat resistance of the sealant layer can be further improved. In addition, although the polyamide/polyethylene graft copolymer can be dispersed in the polypropylene-based resin, there is room for improvement in compatibility. Therefore, by blending the (C) component, the compatibility between the (A) component and the (B) component can be improved, and the heat seal strength can be further improved.

In the exterior material for a storage battery device, the component (A) may contain a cycloolefin copolymer, and the content of the component (A) in the sealant layer may be 5 to 100 parts by mass per 100 parts by mass of the component (B). In this case, more sufficient heat seal strength can be obtained at a heat seal temperature of about 200°C, and excellent heat seal strength can be more sufficiently ensured even in a high-temperature environment.

In the above-mentioned storage device exterior material, the above-mentioned (A) component contains an ethylene/cycloolefin copolymer, the above-mentioned (B) component contains the above-mentioned polypropylene-based resin, and the above-mentioned sealant layer may further contain (C) component: a compatibilizer having a portion compatible with the above-mentioned ethylene/cycloolefin copolymer and a portion compatible with the above-mentioned polypropylene-based resin. By the fact that the (A) component contains an ethylene/cycloolefin copolymer and the (B) component contains a polypropylene-based resin, the heat resistance of the sealant layer can be further improved. In addition, although the ethylene/cycloolefin copolymer can be dispersed in the polypropylene-based resin, there is room for improvement in compatibility. Therefore, by blending the above-mentioned (C) component, the compatibility between the (A) component and the (B) component can be improved, and the heat seal strength can be further improved.

In the above-mentioned storage battery device exterior material, a corrosion prevention treatment layer may be provided on one or both surfaces of the barrier layer. By providing the corrosion prevention treatment layer, the corrosion of the barrier layer can be prevented, and the presence of the corrosion prevention treatment layer can increase the adhesion between the barrier layer and the layer adjacent thereto. In addition, in an all-solid-state battery, a sulfide-based material may be used as an electrolyte, and when moisture penetrates into the exterior material, the sulfide-based compound reacts with water to generate hydrogen sulfide (H ₂ S). This H ₂ S may reduce the adhesion between the barrier layer and the layer adjacent thereto. However, when the above-mentioned storage battery device exterior material is used as an exterior material for an all-solid-state battery, the corrosion prevention treatment layer on the barrier layer surface can impart H ₂ S resistance to the barrier layer, and the adhesion between the barrier layer and the layer adjacent thereto can be prevented from decreasing.

In the electrical storage device packaging material, when the base layer side of the electrical storage device packaging material is the outer side and the sealant layer side is the inner side, at least one of the layers arranged on the inner side of the barrier layer may contain a hydrogen sulfide adsorbent. As described above, there is a risk of hydrogen sulfide ( _H2S ) being generated in an all-solid-state battery, but by having at least one of the layers arranged on the inner side of the barrier layer contain a hydrogen sulfide adsorbent, the layer containing the hydrogen sulfide adsorbent can adsorb and detoxify the _H2S generated inside the packaging material, and the barrier layer, the current collector (particularly copper foil), and the positive electrode containing Ni can be protected from _H2S at a higher level.

In the above-mentioned exterior material for a storage battery device, the thickness of the sealant layer may be 10 to 100 μm. In this case, a good balance can be achieved between thinning the exterior material and improving the heat seal strength in a high-temperature environment.

The above-mentioned exterior material for the power storage device may be for an all-solid-state battery.

The present disclosure also provides an electricity storage device including an electricity storage device main body, a current extraction terminal extending from the electricity storage device main body, and an exterior material for an electricity storage device of the present disclosure that sandwiches the current extraction terminal and houses the electricity storage device main body. The electricity storage device may be an all-solid-state battery.

This disclosure makes it possible to provide an exterior material for a power storage device that can ensure excellent heat seal strength even in a high-temperature environment, and a power storage device using the same.

1 is a schematic cross-sectional view of an exterior material for an energy storage device according to an embodiment of the present disclosure. 1 is a schematic cross-sectional view of an exterior material for an energy storage device according to an embodiment of the present disclosure. 1 is a perspective view of an electricity storage device according to an embodiment of the present disclosure. FIG. 2 is a schematic diagram illustrating a method for preparing a sample for measuring heat seal strength in the examples.

A preferred embodiment of the present disclosure will be described in detail below with reference to the drawings as appropriate. Note that in the drawings, the same or equivalent parts are given the same reference numerals, and duplicate explanations will be omitted. Also, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[Exterior material for power storage device]
Fig. 1 is a cross-sectional view showing an embodiment of an exterior material for a power storage device according to the present disclosure. As shown in Fig. 1, an exterior material (exterior material for a power storage device) 10 according to the present embodiment is a substrate. A material layer 11, a first adhesive layer 12a provided on one side of the base layer 11, and a second adhesive layer 12b provided on the opposite side of the base layer 11 from the first adhesive layer 12a. A barrier layer 13 having first and second corrosion prevention treatment layers 14a, 14b on both sides thereof, and a second adhesive layer 12b provided on the side of the barrier layer 13 opposite to the first adhesive layer 12a. The first corrosion prevention treatment layer 14a is a laminated body having the barrier layer 13 and a sealant layer 16 provided on the opposite side of the second adhesive layer 12b from the barrier layer 13. The first corrosion prevention treatment layer 14b is provided on the surface of the barrier layer 13 facing the base material layer 11, and the second corrosion prevention treatment layer 14b is provided on the surface of the barrier layer 13 facing the sealant layer 16, respectively. In the exterior packaging material 10, the base material layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. That is, in the exterior packaging material 10, the base material layer 11 is disposed on the outer side of the electricity storage device, and the sealant layer 16 is disposed on the inner side of the electricity storage device. Each layer constituting the exterior packaging material 10 will now be described in detail.

<Base layer 11>
The base layer 11 imparts heat resistance in a sealing process when manufacturing the electricity storage device and plays a role in suppressing the occurrence of pinholes that may occur during molding and distribution. In particular, in the case of an exterior material for a large-scale electricity storage device, the base layer 11 can also impart scratch resistance, chemical resistance, insulation, and the like.

The substrate layer 11 is preferably a layer made of a resin film formed from an insulating resin. Examples of the resin film include stretched or unstretched films such as polyester film, polyamide film, and polypropylene film. The substrate layer 11 may be a single layer film made of any of these resin films, or a laminate film made of two or more of these resin films.

Among these, polyester film and polyamide film are preferred as the base layer 11 because of their excellent moldability, and polyamide film is more preferred. These films are preferably biaxially stretched films. Examples of polyester resins constituting polyester films include polyethylene terephthalate. Examples of polyamide resins constituting polyamide films include nylon 6, nylon 6,6, copolymers of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), nylon 11, nylon 12, etc. Among these, nylon 6 (ONy) is preferred because of its excellent heat resistance, puncture strength, and impact strength.

Examples of methods for stretching biaxially stretched films include sequential biaxial stretching, tubular biaxial stretching, and simultaneous biaxial stretching. From the viewpoint of obtaining better deep-draw formability, it is preferable that the biaxially stretched film is stretched by the tubular biaxial stretching method.

In addition, it is preferable that the base layer 11 has a melting peak temperature higher than the melting peak temperature of the sealant layer 16. When the sealant layer 16 has a multi-layer structure, the melting peak temperature of the sealant layer 16 means the melting peak temperature of the layer with the highest melting peak temperature. The melting peak temperature of the base layer 11 is preferably 290°C or higher, more preferably 290 to 350°C. Examples of resin films that can be used as the base layer 11 and have a melting peak temperature in the above range include nylon film, PET film, polyamide film, polyphenylene sulfide film (PPS film), etc. As the base layer 11, a commercially available film may be used, or the base layer 11 may be formed by coating (application of a coating liquid and drying). The base layer 11 may have a single layer structure or a multi-layer structure, and may be formed by applying a thermosetting resin. In addition, the base layer 11 may contain, for example, various additives (for example, a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, etc.).

The difference (T ₁₁ -T ₁₆ ) between the peak melting temperature T ₁₁ of the base material layer 11 and the peak melting temperature T ₁₆ of the sealant layer 16 is preferably 20° C. or more. When this temperature difference is 20° C. or more, deterioration of the appearance of the packaging material 10 caused by heat sealing can be more sufficiently suppressed.

The substrate layer 11 may be provided by directly applying it onto the barrier layer 13 or the first corrosion prevention treatment layer 14a described below. In this case, the first adhesive layer 12a described below is not necessary. The substrate layer 11 can be formed by applying a resin coating liquid such as urethane resin, acrylic resin, polyester resin, etc., and curing it by ultraviolet irradiation, high-temperature heating, aging (curing) treatment, etc. The application method is not particularly limited, and various methods such as gravure coating, reverse coating, roll coating, bar coating, etc. can be used.

The thickness of the substrate layer 11 is preferably 5 to 50 μm, more preferably 6 to 40 μm, even more preferably 10 to 30 μm, and particularly preferably 12 to 30 μm. By making the thickness of the substrate layer 11 5 μm or more, the pinhole resistance and insulating properties of the exterior material for a storage battery device 10 tend to be improved. If the thickness of the substrate layer 11 exceeds 50 μm, the total thickness of the exterior material for a storage battery device 10 becomes large, which is undesirable because it may be necessary to reduce the electrical capacity of the battery.

<First adhesive layer 12a>
The first adhesive layer 12a is a layer that bonds the base material layer 11 and the barrier layer 13. Specific examples of materials constituting the first adhesive layer 12a include polyurethane resins in which a difunctional or higher isocyanate compound is allowed to react with a base material such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol.

The various polyols mentioned above can be used alone or in combination of two or more types depending on the functions and performance required for the exterior material.

Depending on the performance required for the adhesive, various other additives and stabilizers may also be added to the polyurethane resin described above.

The thickness of the first adhesive layer 12a is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, followability, processability, etc., it is preferably, for example, 1 to 10 μm, and more preferably 3 to 7 μm.

<Barrier layer 13>
The barrier layer 13 has a water vapor barrier property that prevents moisture from penetrating into the inside of the electricity storage device. In addition, the barrier layer 13 has extensibility for deep drawing. As the barrier layer 13, for example, various metal foils such as aluminum, stainless steel, copper, etc., or metal vapor deposition films, inorganic oxide vapor deposition films, carbon-containing inorganic oxide vapor deposition films, films provided with these vapor deposition films, etc. can be used. As the film provided with the vapor deposition film, for example, an aluminum vapor deposition film or an inorganic oxide vapor deposition film can be used. These can be used alone or in combination of two or more. As the barrier layer 13, a metal foil is preferable, and an aluminum foil is more preferable, in terms of mass (specific gravity), moisture resistance, processability, and cost.

As the aluminum foil, soft aluminum foil that has been annealed can be preferably used from the viewpoint of imparting the desired ductility during molding, but it is more preferable to use an aluminum foil containing iron for the purpose of imparting further pinhole resistance and ductility during molding. The content of iron in the aluminum foil is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%, based on 100 mass% of the aluminum foil. By having an iron content of 0.1 mass% or more, it is possible to obtain an exterior material 10 having better pinhole resistance and ductility. By having an iron content of 9.0 mass% or less, it is possible to obtain an exterior material 10 having better flexibility. As the aluminum foil, untreated aluminum foil may be used, but it is preferable to use aluminum foil that has been degreased in order to impart corrosion resistance. When the aluminum foil is degreased, the degreased treatment may be performed on only one side of the aluminum foil, or on both sides.

The thickness of the barrier layer 13 is not particularly limited, but taking into consideration the barrier properties, pinhole resistance, and processability, it is preferably 9 to 200 μm, and more preferably 15 to 100 μm.

<First and second corrosion prevention treatment layers 14a, 14b>
The first and second corrosion prevention layers 14a and 14b are layers provided on the surface of the barrier layer 13 to prevent corrosion of the metal foil (metal foil layer) constituting the barrier layer 13. The first corrosion prevention layer 14a plays a role in increasing the adhesion between the barrier layer 13 and the first adhesive layer 12a. The second corrosion prevention layer 14b plays a role in increasing the adhesion between the barrier layer 13 and the second adhesive layer 12b. The first corrosion prevention layer 14a and the second corrosion prevention layer 14b may be layers of the same configuration or layers of different configurations. The first and second corrosion prevention layers 14a and 14b (hereinafter also simply referred to as "corrosion prevention layers 14a and 14b") are formed, for example, by degreasing, hydrothermal conversion, anodizing, chemical conversion, or a combination of these treatments.

Examples of degreasing treatments include acid degreasing and alkaline degreasing. Examples of acid degreasing include a method using an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, or hydrofluoric acid alone or a mixture of these. In addition, by using an acid degreasing agent in which a fluorine-containing compound such as monosodium ammonium difluoride is dissolved in the inorganic acid, not only can the aluminum be degreased, but also a passive aluminum fluoride can be formed, which is effective in terms of corrosion resistance, especially when aluminum foil is used for the barrier layer 13. Examples of alkaline degreasing include a method using sodium hydroxide, etc.

An example of a hydrothermal conversion treatment is the boehmite treatment, in which aluminum foil is immersed in boiling water containing added triethanolamine.

An example of anodizing is anodizing.

Examples of chemical conversion treatments include immersion type and coating type. Examples of immersion type chemical conversion treatments include chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, strontium hydroxide treatment, cerium treatment, ruthenium treatment, and various chemical conversion treatments consisting of mixed phases of these. On the other hand, coating type chemical conversion treatments include a method in which a coating agent having corrosion prevention properties is applied onto the barrier layer 13.

When forming at least a part of the corrosion prevention layer by any of these corrosion prevention treatments, namely hydrothermal conversion treatment, anodizing treatment, or chemical conversion treatment, it is preferable to carry out the above-mentioned degreasing treatment in advance. Note that when using a degreased metal foil, such as a metal foil that has been subjected to an annealing process, as the barrier layer 13, there is no need to carry out a degreasing treatment again when forming the corrosion prevention layers 14a and 14b.

The coating agent used in the paint-type chemical conversion treatment preferably contains trivalent chromium. The coating agent may also contain at least one polymer selected from the group consisting of cationic polymers and anionic polymers, which will be described later.

In addition, among the above treatments, particularly in hydrothermal conversion treatment and anodization treatment, the aluminum foil surface is dissolved by a treatment agent to form aluminum compounds (boehmite, anodization) that have excellent corrosion resistance. Therefore, since a bicontinuous structure is formed from the barrier layer 13 using aluminum foil to the corrosion prevention treatment layers 14a, 14b, the above treatment is included in the definition of chemical conversion treatment. On the other hand, as described later, it is also possible to form the corrosion prevention treatment layers 14a, 14b by a pure coating method alone, which is not included in the definition of chemical conversion treatment. For example, this method uses a sol of a rare earth element oxide such as cerium oxide with an average particle size of 100 nm or less, which has an aluminum corrosion prevention effect (inhibitor effect) and is also environmentally friendly. By using this method, it is possible to impart a corrosion prevention effect to metal foils such as aluminum foils even with a general coating method.

Examples of the above rare earth element oxide sol include sols using various solvents such as water-based, alcohol-based, hydrocarbon-based, ketone-based, ester-based, and ether-based solvents. Of these, water-based sols are preferred.

In order to stabilize the dispersion of the rare earth oxide sol, inorganic acids such as nitric acid, hydrochloric acid, phosphoric acid, or their salts, and organic acids such as acetic acid, malic acid, ascorbic acid, and lactic acid are usually used as dispersion stabilizers. Of these dispersion stabilizers, phosphoric acid in particular is expected to (1) stabilize the dispersion of the sol, (2) improve adhesion to the barrier layer 13 by utilizing the aluminum chelating ability of phosphoric acid, and (3) improve the cohesive force of the corrosion prevention treatment layers 14a, 14b (oxide layers) by easily causing dehydration condensation of phosphoric acid even at low temperatures.

Examples of the phosphoric acid or salt thereof include orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, or their alkali metal salts or ammonium salts. Among them, condensed phosphoric acids such as trimetaphosphoric acid, tetrametaphosphoric acid, hexametaphosphoric acid, and ultrametaphosphoric acid, or their alkali metal salts or ammonium salts, are preferred for functional expression in the exterior material 10. In addition, taking into consideration the drying film-forming properties (drying ability, amount of heat) when forming the corrosion prevention treatment layers 14a, 14b made of rare earth element oxides by various coating methods using the sol of the rare earth element oxide, sodium salts are more preferred because of their excellent dehydration condensation properties at low temperatures. As the phosphate, water-soluble salts are preferred.

The compounding ratio of phosphoric acid (or its salt) to rare earth element oxide is preferably 1 to 100 parts by mass per 100 parts by mass of rare earth element oxide. If the compounding ratio is 1 part by mass or more per 100 parts by mass of rare earth element oxide, the rare earth element oxide sol becomes more stable and the function of the exterior material 10 becomes better. The compounding ratio is more preferably 5 parts by mass or more per 100 parts by mass of rare earth element oxide. Also, if the compounding ratio is 100 parts by mass or less per 100 parts by mass of rare earth element oxide, the function of the rare earth element oxide sol is improved. The compounding ratio is more preferably 50 parts by mass or less per 100 parts by mass of rare earth element oxide, and even more preferably 20 parts by mass or less.

The corrosion prevention treatment layers 14a and 14b formed from the rare earth element oxide sol are aggregates of inorganic particles, so there is a risk that the cohesive strength of the layer itself will be reduced even after the dry curing process. Therefore, in this case, it is preferable that the corrosion prevention treatment layers 14a and 14b are complexed with the following anionic polymer or cationic polymer to compensate for the cohesive strength.

Examples of anionic polymers include polymers having a carboxy group, such as poly(meth)acrylic acid (or its salt), or copolymers copolymerized with poly(meth)acrylic acid as the main component. The copolymerization components of this copolymer include alkyl(meth)acrylate monomers (alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.); (meth)acrylamide, N-alkyl(meth)acrylamide, N,N-dialkyl(meth)acrylamide (alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.); N-alkoxy(meth)acrylamide, N,N-dialkoxy(meth)acrylamide, (alkyi)acrylamide, N-alkoxy(meth ... Examples of the koxy group include methoxy, ethoxy, butoxy, and isobutoxy groups. ), amide group-containing monomers such as N-methylol (meth)acrylamide and N-phenyl (meth)acrylamide; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; glycidyl group-containing monomers such as glycidyl (meth)acrylate and allyl glycidyl ether; silane-containing monomers such as (meth)acryloxypropyl trimethoxysilane and (meth)acryloxypropyl triethoxylane; and isocyanate group-containing monomers such as (meth)acryloxypropyl isocyanate.

These anionic polymers play a role in improving the stability of the corrosion prevention treatment layers 14a, 14b (oxide layers) obtained using the rare earth element oxide sol. This is achieved by the effect of protecting the hard and brittle oxide layer with the acrylic resin component, and the effect of capturing (cation catcher) ion contaminants (especially sodium ions) derived from the phosphate contained in the rare earth element oxide sol. In other words, if the corrosion prevention treatment layers 14a, 14b obtained using the rare earth element oxide sol contain alkali metal ions such as sodium or alkaline earth metal ions, the corrosion prevention treatment layers 14a, 14b tend to deteriorate starting from the places containing these ions. Therefore, the resistance of the corrosion prevention treatment layers 14a, 14b is improved by fixing the sodium ions and the like contained in the rare earth element oxide sol with the anionic polymer.

The corrosion prevention layers 14a, 14b, which combine an anionic polymer and a rare earth oxide sol, have the same corrosion prevention performance as the corrosion prevention layers 14a, 14b formed by chromate treatment of aluminum foil. The anionic polymer is preferably a structure in which a polyanionic polymer, which is essentially water-soluble, is crosslinked. Examples of crosslinking agents used to form this structure include compounds having an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group.

Examples of compounds having an isocyanate group include diisocyanates such as tolylene diisocyanate, xylylene diisocyanate or hydrogenated products thereof, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate or hydrogenated products thereof, and isophorone diisocyanate; or polyisocyanates such as adducts obtained by reacting these isocyanates with polyhydric alcohols such as trimethylolpropane, biuret products obtained by reacting these isocyanates with water, or isocyanurate trimers; or blocked polyisocyanates obtained by blocking these polyisocyanates with alcohols, lactams, oximes, or the like.

Examples of compounds having a glycidyl group include epoxy compounds obtained by reacting glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 14a,14b-butanediol, 1,6-hexanediol, and neopentyl glycol with epichlorohydrin; epoxy compounds obtained by reacting polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, and sorbitol with epichlorohydrin; and epoxy compounds obtained by reacting dicarboxylic acids such as phthalic acid, terephthalic acid, oxalic acid, and adipic acid with epichlorohydrin.

Examples of compounds having a carboxy group include various aliphatic or aromatic dicarboxylic acids. In addition, poly(meth)acrylic acid and alkali (earth) metal salts of poly(meth)acrylic acid may also be used.

Examples of compounds having an oxazoline group include low molecular weight compounds having two or more oxazoline units, or, when a polymerizable monomer such as isopropenyl oxazoline is used, copolymers of acrylic monomers such as (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic hydroxyalkyls.

Alternatively, an anionic polymer may be reacted with a silane coupling agent, more specifically, a carboxy group of the anionic polymer may be selectively reacted with a functional group of the silane coupling agent, and the crosslinking point may be a siloxane bond. In this case, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, etc. may be used. Among these, epoxysilane, aminosilane, and isocyanatesilane are preferred, taking into consideration the reactivity with the anionic polymer or its copolymer.

The ratio of these crosslinking agents to the anionic polymer is preferably 1 to 50 parts by mass, more preferably 10 to 20 parts by mass, per 100 parts by mass of the anionic polymer. If the ratio of the crosslinking agent is 1 part by mass or more per 100 parts by mass of the anionic polymer, the crosslinked structure is easily formed sufficiently. If the ratio of the crosslinking agent is 50 parts by mass or less per 100 parts by mass of the anionic polymer, the pot life of the coating liquid is improved.

The method for crosslinking anionic polymers is not limited to the above-mentioned crosslinking agents, but may also be a method of forming ionic crosslinks using titanium or zirconium compounds.

Examples of cationic polymers include polymers having amines, such as polyethyleneimine, ionic polymer complexes consisting of a polymer having polyethyleneimine and a carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is grafted onto an acrylic main skeleton, polyallylamine or derivatives thereof, and cationic polymers such as aminophenol. Examples of polyallylamine include homopolymers or copolymers of allylamine, allylamine amide sulfate, diallylamine, and dimethylallylamine. These amines may be free amines or may be stabilized with acetic acid or hydrochloric acid. In addition, maleic acid, sulfur dioxide, and the like may be used as copolymer components. Furthermore, types in which the primary amine is partially methoxylated to impart thermal crosslinking properties can be used, and aminophenol can also be used. In particular, allylamine or its derivatives are preferred.

It is preferable to use the cationic polymer in combination with a crosslinking agent having a functional group capable of reacting with amines/imines, such as a carboxy group or a glycidyl group. As a crosslinking agent to be used in combination with the cationic polymer, a polymer having a carboxylic acid that forms an ionic polymer complex with polyethyleneimine can also be used. Examples of the crosslinking agent include polycarboxylic acids (salts) such as polyacrylic acid or its ionic salts, copolymers with comonomers introduced therein, and polysaccharides having a carboxy group, such as carboxymethylcellulose or its ionic salts.

Cationic polymers are more preferred materials in terms of improving adhesion. In addition, like the anionic polymers, cationic polymers are also water-soluble, so it is more preferred to form crosslinked structures to impart water resistance. The crosslinking agent used to form the crosslinked structure in the cationic polymer can be the crosslinking agent described in the anionic polymer section. When a rare earth oxide sol is used as the corrosion prevention treatment layers 14a and 14b, a cationic polymer may be used as the protective layer instead of the anionic polymer.

In order to form a gradient structure with the aluminum foil, the corrosion prevention treatment layer by chemical conversion treatment, such as chromate treatment, is formed by treating the aluminum foil with a chemical conversion treatment agent, particularly a mixture of hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, or salts of these, and then applying a chromium or non-chromium compound to form a chemical conversion treatment layer on the aluminum foil. However, since the above-mentioned chemical conversion treatment uses an acid as the chemical conversion treatment agent, it is accompanied by deterioration of the working environment and corrosion of the coating equipment. On the other hand, unlike chemical conversion treatments such as chromate treatment, the above-mentioned coating-type corrosion prevention treatment layers 14a and 14b do not need to form a gradient structure with respect to the barrier layer 13 using the aluminum foil. Therefore, the properties of the coating agent are not restricted by acidity, alkalinity, neutrality, etc., and a good working environment can be realized. In addition, the coating-type corrosion prevention treatment layers 14a and 14b are preferable because alternatives to chromate treatment using chromium compounds are required from the viewpoint of environmental hygiene.

From the above, examples of combinations of the above-mentioned coating-type corrosion prevention treatments include (1) only rare earth element oxide sol, (2) only anionic polymer, (3) only cationic polymer, (4) rare earth element oxide sol + anionic polymer (laminated composite), (5) rare earth element oxide sol + cationic polymer (laminated composite), (6) (rare earth element oxide sol + anionic polymer: laminated composite) / cationic polymer (multilayered), (7) (rare earth element oxide sol + cationic polymer: laminated composite) / anionic polymer (multilayered), etc. Among these, (1) and (4) to (7) are preferred, and (4) to (7) are particularly preferred. However, this embodiment is not limited to the above combinations. For example, as an example of the selection of a corrosion prevention treatment, a cationic polymer is a very preferable material because it has good adhesion to the modified polyolefin resin mentioned in the description of the second adhesive layer, adhesive resin layer, or sealant layer described below. Therefore, when the second adhesive layer, adhesive resin layer, or sealant layer is composed of a modified polyolefin resin, it is possible to design the surface in contact with the second adhesive layer, adhesive resin layer, or sealant layer by providing a cationic polymer (for example, configurations (5) and (6)).

The corrosion prevention treatment layers 14a and 14b are not limited to the layers described above. For example, they may be formed using a treatment agent in which phosphoric acid and a chromium compound are mixed with a resin binder (such as aminophenol), as in the case of coating-type chromate, which is a known technology. By using this treatment agent, a layer that combines both corrosion prevention function and adhesion can be formed. In addition, although it is necessary to consider the stability of the coating liquid, a coating agent in which a rare earth element oxide sol and a polycationic polymer or a polyanionic polymer are mixed in advance into a one-component solution can be used to form a layer that combines both corrosion prevention function and adhesion.

The mass per unit area of the corrosion prevention treatment layers 14a and 14b is preferably 0.005 to 0.200 g/ ^m2 , more preferably 0.010 to 0.100 g/ ^m2 , regardless of whether the layer is a multilayer structure or a single layer structure. If the mass per unit area is 0.005 g/ ^m2 or more, the barrier layer 13 is easily provided with a corrosion prevention function. Even if the mass per unit area exceeds 0.200 g/ ^m2 , the corrosion prevention function does not change much. On the other hand, when a rare earth element oxide sol is used, if the coating is thick, the curing due to heat during drying may be insufficient, which may result in a decrease in cohesive force. The thickness of the corrosion prevention treatment layers 14a and 14b can be calculated from their specific gravity.

From the viewpoint of easily maintaining the adhesion between the sealant layer and the barrier layer, the corrosion prevention treatment layers 14a and 14b may be, for example, in an embodiment containing cerium oxide, 1 to 100 parts by mass of phosphoric acid or a phosphate salt per 100 parts by mass of the cerium oxide, and a cationic polymer, or may be formed by subjecting the barrier layer 13 to a chemical conversion treatment, or may be formed by subjecting the barrier layer 13 to a chemical conversion treatment and contain a cationic polymer.

<Second adhesive layer 12b>
The second adhesive layer 12b is a layer that bonds the barrier layer 13, on which the second corrosion prevention treatment layer 14b is formed, to the sealant layer 16. For the second adhesive layer 12b, a general adhesive for bonding a barrier layer and a sealant layer can be used.

When the second corrosion prevention treatment layer 14b has a layer containing at least one polymer selected from the group consisting of the cationic polymer and the anionic polymer described above, the second adhesive layer 12b is preferably a layer containing a compound (hereinafter also referred to as a "reactive compound") that is reactive with the polymer contained in the second corrosion prevention treatment layer 14b.

For example, when the second corrosion prevention treatment layer 14b contains a cationic polymer, the second adhesive layer 12b contains a compound reactive with the cationic polymer. When the second corrosion prevention treatment layer 14b contains an anionic polymer, the second adhesive layer 12b contains a compound reactive with the anionic polymer. When the second corrosion prevention treatment layer 14b contains a cationic polymer and an anionic polymer, the second adhesive layer 12b contains a compound reactive with the cationic polymer and a compound reactive with the anionic polymer. However, the second adhesive layer 12b does not necessarily have to contain the above two types of compounds, and may contain a compound reactive with both the cationic polymer and the anionic polymer. Here, "reactive" means forming a covalent bond with the cationic polymer or the anionic polymer. The second adhesive layer 12b may further contain an acid-modified polyolefin resin.

The compound reactive with the cationic polymer may be at least one compound selected from the group consisting of a polyfunctional isocyanate compound, a glycidyl compound, a compound having a carboxy group, and a compound having an oxazoline group.

These polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group include the polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group exemplified above as crosslinking agents for crosslinking cationic polymers. Among these, polyfunctional isocyanate compounds are preferred because they are highly reactive with cationic polymers and can easily form crosslinked structures.

Examples of compounds that are reactive with anionic polymers include at least one compound selected from the group consisting of glycidyl compounds and compounds having an oxazoline group. Examples of these glycidyl compounds and compounds having an oxazoline group include the glycidyl compounds and compounds having an oxazoline group exemplified above as crosslinking agents for forming a crosslinked structure from a cationic polymer. Among these, glycidyl compounds are preferred because of their high reactivity with anionic polymers.

When the second adhesive layer 12b contains an acid-modified polyolefin resin, it is preferable that the reactive compound also has a reactivity with the acidic groups in the acid-modified polyolefin resin (i.e., forms a covalent bond with the acidic groups). This further enhances adhesion to the second corrosion prevention treatment layer 14b. In addition, the acid-modified polyolefin resin forms a crosslinked structure, further improving the solvent resistance of the exterior material 10.

The content of the reactive compound is preferably from one to ten times the equivalent of the acidic groups in the acid-modified polyolefin resin. If the amount is equal to or more than one, the reactive compound will react sufficiently with the acidic groups in the acid-modified polyolefin resin. On the other hand, if the amount exceeds ten times the equivalent, the crosslinking reaction with the acid-modified polyolefin resin will be fully saturated, and there will be unreacted material, raising concerns about a decrease in various performances. Therefore, for example, the content of the reactive compound is preferably 5 to 20 parts by mass (solids ratio) per 100 parts by mass of the acid-modified polyolefin resin.

The acid-modified polyolefin resin is a polyolefin resin to which an acidic group has been introduced. Examples of the acidic group include a carboxy group, a sulfonic acid group, and an acid anhydride group, and maleic anhydride groups and (meth)acrylic acid groups are particularly preferred. As the acid-modified polyolefin resin, for example, the same one as the modified polyolefin resin (a) used in the first sealant layer 16a described below can be used.

The second adhesive layer 12b may contain various additives such as flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers.

The second adhesive layer 12b may contain, for example, an acid-modified polyolefin and at least one curing agent selected from the group consisting of a polyfunctional isocyanate compound, a glycidyl compound, a compound having a carboxy group, a compound having an oxazoline group, and a carbodiimide compound, in order to suppress a decrease in laminate strength and further suppress a decrease in insulating properties. Examples of carbodiimide compounds include N,N'-di-o-toluylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-di-2,6-dimethylphenylcarbodiimide, N,N'-bis(2,6-diisopropylphenyl)carbodiimide, N,N'-dioctyldecylcarbodiimide, N-triyl-N'-cyclohexylcarbodiimide, N,N'-di-2,2-di-t-butylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, N,N'-di-p-nitrophenylcarbodiimide, N,N'-di-p-aminophenylcarbodiimide, N,N'-di-p-hydroxyphenylcarbodiimide, N,N'-di-cyclohexylcarbodiimide, and N,N'-di-p-toluylcarbodiimide.

The adhesive that forms the second adhesive layer 12b can also be, for example, a polyurethane adhesive that combines polyester polyol made of hydrogenated dimer fatty acid and diol with polyisocyanate.

The thickness of the second adhesive layer 12b is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength and processability, etc., it is preferably 1 to 10 μm, and more preferably 3 to 7 μm.

<Sealant layer 16>
The sealant layer 16 is a layer that imparts heat-sealing sealability to the exterior material 10. The sealant layer 16 is a layer that contains: (A) component: a compound that contains a polyolefin unit and has a melting point of 175° C. or higher or a glass transition temperature of 75° C. or higher; and (B) component: at least one resin selected from the group consisting of polyethylene-based resins and polypropylene-based resins.

When the sealant layer is a single layer as shown in FIG. 1, the sealant layer is a layer containing the above-mentioned (A) component and (B) component. When the sealant layer has two or more layers, at least one layer may be a layer containing the above-mentioned (A) component and (B) component, and it is preferable that at least the innermost layer (the layer disposed at the position farthest from the base layer 11) is a layer containing the above-mentioned (A) component and (B) component. The sealant layer 16 may further contain a (C) component: a compatibilizer having a portion compatible with the (A) component and a portion compatible with the (B) component. The sealant layer 16 may further contain a hydrogen sulfide adsorbing substance.

(Component (A))
The (A) component is a compound containing a polyolefin unit and having a melting point (Tm) of 175°C or higher or a glass transition temperature (Tg) of 75°C or higher. Examples of the polyolefin unit include a polyethylene unit, a polypropylene unit, and a polybutylene unit. The (A) component is preferably a copolymer of an olefin and another copolymerizable monomer. Examples of the (A) component include a polyamide/polyolefin graft copolymer, a cycloolefin/olefin copolymer (cycloolefin copolymer), and the like.

An example of a polyamide/polyolefin graft copolymer is a polyamide/polyethylene graft copolymer. Commercially available polyamide/polyolefin graft copolymers include "Aporya LP2" (melting point: 216°C) and "Aporya LP21H" (melting point: 216°C) manufactured by Arkema.

Examples of cycloolefin copolymers include ethylene/cycloolefin copolymers. Commercially available cycloolefin copolymers include "APEL" manufactured by Mitsui Chemicals, Inc. and "TOPAS" manufactured by TOPAS Advanced Polymers GmbH. Examples of "APEL" include "APL6509" (Tg: 80°C), "APL6011T" (Tg: 105°C), "APL6013T" (Tg: 125°C), and "APL6015T" (Tg: 145°C).

The (A) component is a compound having a melting point of 175°C or higher or a glass transition temperature of 75°C or higher. By using the (A) component having a melting point of 175°C or higher or a glass transition temperature of 75°C or higher, the sealant layer 16 can obtain sufficient heat seal strength at a heat seal temperature of about 200°C, and can maintain sufficient heat seal strength even in a high temperature (for example, about 150°C) environment. The (A) component may be a compound having a melting point of 175°C or higher and a glass transition temperature of 75°C or higher. On the other hand, when a compound having a melting point less than 175°C and a glass transition temperature less than 75°C, a compound having a melting point less than 175°C and no glass transition point, or a compound having a glass transition temperature less than 75°C and no melting point is used, it is not always possible to ensure sufficient heat seal strength in a high temperature (about 150°C) environment.

The melting point of component (A) may be 180°C or higher, 190°C or higher, 200°C or higher, or 210°C or higher, from the viewpoint of further improving the heat seal strength in a high temperature (e.g., about 150°C) environment. Also, the melting point of component (A) may be 250°C or lower, or 240°C or lower, from the viewpoint of obtaining a more sufficient heat seal strength at a heat seal temperature of about 200°C.

The glass transition temperature of component (A) may be 80°C or higher, 90°C or higher, 100°C or higher, or 120°C or higher, from the viewpoint of further improving the heat seal strength in a high temperature (e.g., about 150°C) environment. Also, the glass transition temperature of component (A) may be 200°C or lower, or 180°C or lower, from the viewpoint of obtaining a more sufficient heat seal strength at a heat seal temperature of about 200°C.

The content of component (A) in the sealant layer 16 is preferably 5 to 100 parts by mass, more preferably 10 to 90 parts by mass, and even more preferably 20 to 80 parts by mass, per 100 parts by mass of component (B). By having a content of component (A) of 5 parts by mass or more, it is possible to more sufficiently ensure excellent heat seal strength even in high-temperature environments, and by having a content of component (A) of 100 parts by mass or less, it is possible to obtain more sufficient heat seal strength at a heat seal temperature of about 200°C and to suppress a decrease in flexibility of the sealant layer and the resulting embrittlement.

(Component (B))
The component (B) is at least one resin selected from the group consisting of polyethylene resins and polypropylene resins. The component (B) is a component that becomes the base resin of the sealant layer 16.

Examples of polyethylene resins include high-density polyethylene, branched low-density polyethylene, and linear low-density polyethylene. Among these, from the viewpoint of film-forming properties, branched low-density polyethylene and linear low-density polyethylene are preferred, and branched low-density polyethylene is more preferred.

Polypropylene-based resins are resins obtained from polymerized monomers including propylene. Examples of polypropylene-based resins include homopolypropylene and random polypropylene. From the viewpoint of the basic performance of the packaging material such as heat seal strength, the polypropylene-based resin is preferably a random polypropylene, and more preferably a propylene-ethylene random copolymer. Since propylene-ethylene random copolymers have excellent heat sealability at low temperatures, the use of component (A) can suppress the increase in the heat seal temperature required to obtain sufficient heat seal strength, and more sufficient heat seal strength can be obtained at a heat seal temperature of about 200°C.

In the propylene-ethylene random copolymer, the ethylene content is preferably 0.1 to 10% by mass, more preferably 1 to 7% by mass, and even more preferably 2 to 5% by mass. When the ethylene content is 0.1% by mass or more, the copolymerization of ethylene tends to provide impact resistance and improve seal strength and mold whitening resistance. When the ethylene content is 10% by mass or less, the melting point tends to be prevented from dropping too much, and the occurrence of excess sealed portions tends to be more sufficiently suppressed. The ethylene content can be calculated from the mixing ratio of the monomers during polymerization.

The melting point of the propylene-ethylene random copolymer is preferably 120 to 160°C, and more preferably 125 to 160°C. If the melting point is 120°C or higher, there is a tendency for the occurrence of excess sealing portions to be more sufficiently suppressed.

The propylene-ethylene random copolymer may be acid-modified, for example, an acid-modified propylene-ethylene random copolymer graft-modified with maleic anhydride. By using an acid-modified propylene-ethylene random copolymer, adhesion to the tab lead can be maintained even without a tab sealant.

Propylene-ethylene random copolymers can be used alone or in combination of two or more.

(Component (C))
In order to improve the compatibility between the (A) and (B) components, the sealant layer 16 may further contain, as the (C) component, a compatibilizer having a portion compatible with the (A) component and a portion compatible with the (B) component. The (C) component is preferably used when the (A) component is incompatible with the (B) component. When the (A) component is incompatible with the (B) component, the sealant layer 16 has a sea-island structure in which the (A) component is dispersed in the (B) component, which is the base resin. By adding the above-mentioned compatibilizer thereto, the adhesive strength of the interface of the sea-island structure can be improved, and thus the heat seal strength can be further improved.

When component (B) is a polypropylene-based resin such as a propylene-ethylene random copolymer, and component (A) is a copolymer containing a polyethylene unit such as a polyamide/polyethylene graft copolymer or an ethylene/cycloolefin copolymer, component (C) can be a compatibilizer having a portion compatible with the polypropylene-based resin and a portion compatible with the copolymer containing the polyethylene unit.

As the (C) component, for example, a block copolymer composed of a polyethylene unit composed of polyethylene or ethylene-α-olefin copolymer and a polypropylene unit composed of polypropylene or propylene-α-olefin copolymer, a block copolymer composed of a polyethylene unit and an ethylene-butylene copolymer unit, or a block copolymer composed of a polyethylene unit and an ethylene-1-octene copolymer unit can be used. Such a block copolymer may have any structure of a diblock copolymer, a triblock copolymer, or a multiblock copolymer. When the (B) component is the above-mentioned polypropylene-based resin and the (A) component is a copolymer containing the above-mentioned polyethylene unit, by using the above-mentioned block copolymer as the (C) component, the polypropylene-based resin of the (B) component and the polypropylene unit, ethylene-butylene copolymer unit, or ethylene-1-octene copolymer unit of the (C) component are compatible with each other, and the polyethylene unit of the (A) component and the polyethylene unit of the (C) component are compatible with each other.

The above-mentioned compatibilizers can be used alone or in combination of two or more.

When the sealant layer 16 contains the (C) component, the content of the (C) component in the sealant layer 16 is preferably 1 to 40 parts by mass, more preferably 2 to 25 parts by mass, even more preferably 2 to 20 parts by mass, and particularly preferably 7 to 15 parts by mass, relative to 100 parts by mass of the total of the (A) and (B) components. When the (C) component content is 1 part by mass or more, it becomes easier to improve the adhesion strength of the sea-island interface, and it becomes easier to obtain an improved effect in heat seal strength. On the other hand, when the (C) component content is 40 parts by mass or less, it becomes easier to suppress a decrease in the cohesive strength and heat seal strength of the sealant layer 16 as a whole.

When the sealant layer 16 is composed of multiple layers, it is preferable that component (C) is added to all layers, but if it is added to at least one layer, the above-mentioned effect of improving the heat seal strength can be obtained.

(Hydrogen sulfide adsorbent)
The sealant layer 16 may further contain a hydrogen sulfide adsorption substance. When the sealant layer 16 contains a hydrogen sulfide adsorption substance, hydrogen sulfide that may be generated in an all-solid-state battery using a sulfide-based solid electrolyte can be captured and rendered harmless by the sealant layer 16. Note that, even when the hydrogen sulfide adsorption substance is added to the second adhesive layer 12b or the adhesive resin layer 15 described later, the same effect as above can be achieved, but when the sealant layer 16, which is the innermost layer, contains a hydrogen sulfide adsorption substance, a more excellent hydrogen sulfide adsorption effect can be obtained. When the base layer 11 side of the exterior material 10 is the outer side and the sealant layer 16 side is the inner side, the hydrogen sulfide adsorption substance is preferably contained in at least one of the layers arranged on the inner side of the barrier layer 13, but may be contained in at least one of the layers arranged on the outer side of the barrier layer 13. For example, the first adhesive layer 12a may contain a hydrogen sulfide adsorption substance.

Examples of hydrogen sulfide adsorbing substances include zinc oxide, amorphous metal silicates (mainly those in which the metal is copper or zinc), hydrates of zirconium and lanthanoid elements, tetravalent metal phosphates (particularly those in which the metal is copper), mixtures of zeolite and zinc ions, mixtures of zeolite, zinc oxide and copper (II) oxide, potassium permanganate, sodium permanganate, silver sulfate, silver acetate, etc. Among these, zinc oxide is preferred from the standpoint of ease of rendering hydrogen sulfide harmless and from the standpoint of cost and handling. One type of hydrogen sulfide adsorbing substance can be used alone, or two or more types can be used in combination.

When the sealant layer 16 contains a hydrogen sulfide adsorbent, the content of the hydrogen sulfide adsorbent in the sealant layer 16 is preferably 0.01 to 30 mass %, and more preferably 0.1 to 20 mass %, based on the total solid content of the sealant layer 16. If the content of the hydrogen sulfide adsorbent is less than 0.01 mass %, the effect of detoxifying hydrogen sulfide is small, and if it exceeds 30 mass %, the physical properties of the sealant layer 16, such as the sealing strength, tend to decrease.

(Additives)
The sealant layer 16 may further contain additive components other than the above-mentioned components. Examples of additive components include polyolefin-based elastomers. The polyolefin-based elastomer may be compatible with the (B) component or may not be compatible with it, but may contain both a compatible polyolefin-based elastomer that is compatible and a non-compatible polyolefin-based elastomer that is not compatible with it. Being compatible (compatible system) means that the dispersed phase has a size of 1 nm or more and less than 500 nm dispersed in the (B) component. Not being compatible (non-compatible system) means that the dispersed phase has a size of 500 nm or more and less than 20 μm dispersed in the (B) component.

When component (B) is a polypropylene resin, examples of compatible polyolefin elastomers include propylene-butene-1 random copolymers, and examples of incompatible polyolefin elastomers include ethylene-butene-1 random copolymers. The polyolefin elastomers can be used alone or in combination of two or more.

When the sealant layer 16 contains a polyolefin-based elastomer, the content of the polyolefin-based elastomer in the sealant layer 16 may be 5 to 40 mass % or 10 to 40 mass % based on the total solid content of the sealant layer 16. If the content of the polyolefin-based elastomer is 5 mass % or more, the effect of improving the sealing properties can be obtained more sufficiently, and if it is 40 mass % or less, the deterioration of the heat resistance of the sealant layer 16 can be suppressed.

The sealant layer 16 may also contain additives such as slip agents, antiblocking agents, antioxidants, light stabilizers, and flame retardants. The content of these additives is preferably 5 parts by mass or less, assuming that the total mass of the sealant layer 16 is 100 parts by mass.

The thickness of the sealant layer 16 is not particularly limited, but from the viewpoint of the volumetric energy density of the battery, it is preferably in the range of 5 to 150 μm, more preferably in the range of 10 to 120 μm, and even more preferably in the range of 20 to 100 μm.

The above describes in detail a preferred embodiment of the exterior material for a power storage device according to this embodiment, but the present disclosure is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present disclosure as described in the claims.

For example, FIG. 1 shows a case where corrosion prevention layers 14a and 14b are provided on both sides of the barrier layer 13, but only one of the corrosion prevention layers 14a and 14b may be provided, or no corrosion prevention layer may be provided.

In FIG. 1, the barrier layer 13 and the sealant layer 16 are laminated using the second adhesive layer 12b, but the barrier layer 13 and the sealant layer 16 may be laminated using an adhesive resin layer 15 as in the exterior material for a storage battery device 20 shown in FIG. 2. In addition, in the exterior material for a storage battery device 20 shown in FIG. 2, the second adhesive layer 12b may be provided between the barrier layer 13 and the adhesive resin layer 15.

<Adhesive resin layer 15>
The adhesive resin layer 15 is generally composed of an adhesive resin composition as a main component and additive components as necessary. The adhesive resin composition is not particularly limited, but may be a modified polyolefin resin. It is preferred that it includes

The modified polyolefin resin is preferably a polyolefin resin graft-modified with an unsaturated carboxylic acid derivative derived from an unsaturated carboxylic acid, or an acid anhydride or ester thereof.

Examples of polyolefin resins include low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-α-olefin copolymer, homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymer.

The modified polyolefin resin is preferably a polyolefin resin modified with maleic anhydride. Suitable modified polyolefin resins include, for example, "Admer" manufactured by Mitsui Chemicals, Inc. and "Modic" manufactured by Mitsubishi Chemical Corporation. Such modified polyolefin resins have excellent reactivity with various metals and polymers having various functional groups, and this reactivity can be utilized to impart adhesion to the adhesive resin layer 15. In addition, the adhesive resin layer 15 may contain various additives, such as compatible and incompatible elastomers, flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers, as necessary.

The thickness of the adhesive resin layer 15 is not particularly limited, but from the viewpoint of stress relaxation and moisture permeability, it is preferable that the thickness be the same as or less than that of the sealant layer 16.

In addition, in the exterior material 20 for a storage battery device, the total thickness of the adhesive resin layer 15 and the sealant layer 16 is preferably in the range of 5 to 150 μm, and more preferably in the range of 20 to 100 μm, from the viewpoint of achieving both a thin film and improved heat seal strength in a high-temperature environment.

[Method of manufacturing exterior material]
Next, a description will be given of an example of a method for manufacturing the exterior packaging material 10 shown in Fig. 1. Note that the method for manufacturing the exterior packaging material 10 is not limited to the following method.

The manufacturing method of the exterior material 10 of this embodiment is generally composed of the steps of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, bonding the base layer 11 and the barrier layer 13 together using the first adhesive layer 12a, further laminating the sealant layer 16 via the second adhesive layer 12b to produce a laminate, and, if necessary, aging the resulting laminate.

(Laminating step of corrosion prevention treatment layers 14a, 14b on barrier layer 13)
This step is a step of forming the corrosion prevention treatment layers 14a, 14b on the barrier layer 13. As a method for this, as described above, there are methods of subjecting the barrier layer 13 to a degreasing treatment, a hydrothermal conversion treatment, an anodizing treatment, a chemical conversion treatment, and a method of applying a coating agent having corrosion prevention properties.

In addition, when the corrosion prevention treatment layers 14a and 14b are multi-layered, for example, the coating liquid (coating agent) constituting the lower corrosion prevention treatment layer (barrier layer 13 side) may be applied to the barrier layer 13 and baked to form a first layer, and then the coating liquid (coating agent) constituting the upper corrosion prevention treatment layer may be applied to the first layer and baked to form a second layer.

Degreasing treatment can be performed by spraying or immersion. Hydrothermal conversion treatment and anodizing treatment can be performed by immersion. Chemical conversion treatment can be performed by selecting an appropriate method such as immersion, spraying, or coating depending on the type of chemical conversion treatment.

A variety of methods can be used to apply coating agents with corrosion prevention properties, including gravure coating, reverse coating, roll coating, and bar coating.

As mentioned above, the various treatments may be performed on either one or both sides of the metal foil. In the case of one-sided treatment, it is preferable that the treated side is the side on which the sealant layer 16 is laminated. If required, the above treatments may also be performed on the surface of the base layer 11.

The coating amount of the coating agent for forming the first layer and the second layer is preferably 0.005 to 0.200 g/ ^m2 , and more preferably 0.010 to 0.100 g/ ^m2 .

If dry curing is required, this can be done at a base material temperature in the range of 60 to 300°C, depending on the drying conditions of the corrosion prevention layers 14a and 14b used.

(Step of bonding the substrate layer 11 and the barrier layer 13)
This process is a process of bonding the barrier layer 13 provided with the corrosion prevention treatment layers 14a and 14b to the base material layer 11 via the first adhesive layer 12a. The bonding method may be dry lamination, non-solvent lamination, wet lamination, or other method, and the two are bonded together using the material constituting the first adhesive layer 12a described above. The first adhesive layer 12a is provided in a dry coating amount of 1 to 10 g/ ^m2 , more preferably 3 to 7 g/ ^m2 .

(Laminating step of second adhesive layer 12b and sealant layer 16)
This step is a step of bonding the sealant layer 16 via the second adhesive layer 12b to the second corrosion prevention treatment layer 14b side of the barrier layer 13. Examples of the bonding method include a wet process and dry lamination.

In the case of a wet process, the solution or dispersion of the adhesive constituting the second adhesive layer 12b is applied onto the second corrosion prevention treatment layer 14b, and the solvent is removed at a predetermined temperature (a temperature equal to or higher than the melting point of the adhesive if the adhesive contains an acid-modified polyolefin resin), and a dry film is formed, or a baking process is performed as necessary after the dry film is formed. The sealant layer 16 is then laminated to produce the exterior material 10. Examples of coating methods include the various coating methods exemplified above.

In this case, the sealant layer 16 can be produced by a melt extrusion molding machine using a resin composition for forming a sealant layer that contains the above-mentioned components (A) and (B), and optionally the component (C), a hydrogen sulfide adsorbent, and additional components. From the viewpoint of productivity, the processing speed of the melt extrusion molding machine can be set to 80 m/min or more.

(Aging treatment process)
This step is a step of aging (curing) the laminate. By aging the laminate, it is possible to promote adhesion between the barrier layer 13, the second corrosion prevention treatment layer 14b, the second adhesive layer 12b, and the sealant layer 16. The aging treatment can be performed at a temperature range of room temperature to 100° C. The aging time is, for example, 1 to 10 days.

In this manner, the exterior material 10 of this embodiment can be manufactured as shown in FIG.

Next, an example of a method for manufacturing the exterior material 20 shown in FIG. 2 will be described. Note that the method for manufacturing the exterior material 20 is not limited to the following method.

The manufacturing method of the exterior material 20 of this embodiment is generally composed of a step of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, a step of bonding the base material layer 11 and the barrier layer 13 together using the first adhesive layer 12a, a step of further laminating the adhesive resin layer 15 and the sealant layer 16 to prepare a laminate, and a step of heat treating the obtained laminate, if necessary. Note that the steps up to the step of bonding the base material layer 11 and the barrier layer 13 can be carried out in the same manner as the manufacturing method of the exterior material 10 described above.

(Laminating Step of Adhesive Resin Layer 15 and Sealant Layer 16)
This step is a step of forming an adhesive resin layer 15 and a sealant layer 16 on the second corrosion prevention treatment layer 14b formed in the previous step. The method includes a method of sand laminating the adhesive resin layer 15 together with the sealant layer 16 using an extrusion laminator. Furthermore, lamination is also possible by a tandem lamination method in which the adhesive resin layer 15 and the sealant layer 16 are extruded, or a co-extrusion method. In forming the adhesive resin layer 15 and the sealant layer 16, for example, each component is blended so as to satisfy the above-mentioned configuration of the adhesive resin layer 15 and the sealant layer 16. The above-mentioned resin composition for forming the sealant layer is used to form the sealant layer 16.

This process produces a laminate in which the layers are stacked in the following order: base layer 11/first adhesive layer 12a/first corrosion prevention treatment layer 14a/barrier layer 13/second corrosion prevention treatment layer 14b/adhesive resin layer 15/sealant layer 16, as shown in FIG. 2.

The adhesive resin layer 15 may be laminated by directly extruding the dry-blended materials using an extrusion laminator to obtain the above-mentioned material composition. Alternatively, the adhesive resin layer 15 may be laminated by extruding the granulated material, which has been melt-blended in advance using a melt kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer, using an extrusion laminator.

The sealant layer 16 may be laminated by directly extruding the materials dry-blended to have the above-mentioned material composition as the components of the resin composition for forming the sealant layer using an extrusion laminator. Alternatively, the adhesive resin layer 15 and the sealant layer 16 may be laminated by a tandem lamination method in which the adhesive resin layer 15 and the sealant layer 16 are extruded using an extrusion laminator, or a co-extrusion method, using a granulated product obtained by melt blending in advance using a melt kneading device such as a single screw extruder, a twin screw extruder, or a Brabender mixer. Alternatively, a sealant monolayer may be formed in advance as a cast film using the resin composition for forming the sealant layer, and this film may be laminated together with the adhesive resin by a method of sand lamination. The formation speed (processing speed) of the adhesive resin layer 15 and the sealant layer 16 may be, for example, 80 m/min or more from the viewpoint of productivity.

(Heat treatment process)
This step is a step of heat-treating the laminate. Heat-treating the laminate can improve adhesion between the barrier layer 13, the second corrosion prevention treatment layer 14b, the adhesive resin layer 15, and the sealant layer 16. As a method of heat treatment, it is preferable to treat at a temperature at least equal to or higher than the melting point of the adhesive resin layer 15.

In this manner, the exterior material 20 of this embodiment can be manufactured as shown in FIG. 2.

The above describes in detail preferred embodiments of the exterior material for a power storage device according to the present disclosure, but the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present disclosure as described in the claims.

The exterior material for an electric storage device of the present disclosure can be suitably used as an exterior material for an electric storage device such as a secondary battery, such as a lithium ion battery, a nickel metal hydride battery, or a lead acid battery, and an electrochemical capacitor, such as an electric double layer capacitor. In particular, the exterior material for an electric storage device of the present disclosure is suitable as an exterior material for an all-solid-state battery using a solid electrolyte.

[Electricity storage device]
FIG. 3 is a perspective view showing one embodiment of a storage device produced using the above-mentioned exterior material. As shown in FIG. 3, the storage device 50 includes a battery element (storage device main body) 52, two metal terminals (current extraction terminals) 53 for extracting current from the battery element 52 to the outside, and an exterior material 10 that hermetically encloses the battery element 52. The exterior material 10 is the exterior material 10 according to the present embodiment described above. In the exterior material 10, the base material layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. That is, the exterior material 10 is configured to enclose the battery element 52 inside by folding one laminate film in two and heat-sealing it, or by overlapping and heat-sealing two laminate films, so that the base material layer 11 is on the outer side of the storage device 50 and the sealant layer 16 is on the inner side of the storage device 50. Note that in the storage device 50, the exterior material 20 may be used instead of the exterior material 10.

The battery element 52 is made by sandwiching an electrolyte between a positive electrode and a negative electrode. The metal terminal 53 is a part of the current collector that is taken out from the exterior material 10, and is made of a metal foil such as copper foil or aluminum foil.

The power storage device 50 of this embodiment may be an all-solid-state battery. In this case, a solid electrolyte such as a sulfide-based solid electrolyte is used as the electrolyte of the battery element 52. The power storage device 50 of this embodiment uses the exterior material 10 of this embodiment, so that excellent heat seal strength can be ensured even when used in a high-temperature environment.

The present disclosure will be explained in more detail below based on examples, but the present disclosure is not limited to the following examples.

[Materials used]
The materials used in the examples and comparative examples are shown below.

<Base layer (thickness 25 μm)>
A polyethylene terephthalate film, one side of which had been subjected to a corona treatment, was used.

<First adhesive layer (thickness: 4 μm)>
A polyurethane adhesive (manufactured by Toyo Ink Co., Ltd.) was used, which is a mixture of a polyester polyol-based base material and a tolylene diisocyanate adduct-based curing agent.

<First corrosion prevention treatment layer (substrate layer side) and second corrosion prevention treatment layer (sealant layer side)>
(CL-1): "Sodium polyphosphate-stabilized cerium oxide sol" was used, which was adjusted to a solid content concentration of 10% by mass using distilled water as a solvent. The sodium polyphosphate-stabilized cerium oxide sol was obtained by mixing 10 parts by mass of sodium salt of phosphoric acid with 100 parts by mass of cerium oxide.
(CL-2): A composition consisting of 90% by mass of "polyallylamine (manufactured by Nitto Boseki Co., Ltd.)" and 10% by mass of "polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation)" adjusted to a solid content concentration of 5% by mass using distilled water as a solvent was used.

<Barrier layer (thickness 40 μm)>
Annealed and degreased soft aluminum foil (manufactured by Toyo Aluminum Co., Ltd., "8079 material") was used.

<Second adhesive layer (thickness: 3 μm)>
An epoxy adhesive was used in which a mixture of 100 parts by mass of epoxy resin (manufactured by ADEKA Corporation, product name: EP4100) and 25 parts by mass of a polyamidoamine-based curing agent (manufactured by ADEKA Corporation, product name: EH4602) was diluted with ethyl acetate to a solid content of 30% by mass.

<Sealant Layer>
The following materials were prepared as components constituting the resin composition for forming a sealant layer.

(Component (B))
B-1: Propylene-ethylene random copolymer (glass transition temperature: -5°C, melting point: 135°C).
B-2: Branched low density polyethylene resin (glass transition temperature: -125°C, melting point: 105°C).

(Component (A))
A-1: Aporia LP2 (trade name, manufactured by Arkema, melting point: 216°C)
A-2: APL6013T (product name, manufactured by Mitsui Chemicals, Inc., glass transition temperature: 125° C.)
A-3: APL6509T (product name, manufactured by Mitsui Chemicals, Inc., glass transition temperature: 80° C.)

(Component (A'))
A'-1: Aporya LC3 (trade name, manufactured by Arkema, melting point: 130°C, glass transition temperature: none)
A'-2: Vylon RN-9300 (product name, Toyobo Co., Ltd., melting point: 198°C, glass transition temperature: 73°C, crystalline polyester resin having no polyolefin unit)

(Component (C))
C-1: INTUNE (product name, manufactured by Dow)
C-2: DYNARON (product name, manufactured by JSR Corporation)
C-3: BIOLLOY NM110NP (product name, manufactured by JSR Corporation, polyester/polyolefin compatibilizer)

(Hydrogen sulfide adsorbent)
Zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.)

[Preparation of exterior material]
Example 1
First, a first and a second corrosion prevention treatment layer were provided on the barrier layer by the following procedure. That is, (CL-1) was applied to both surfaces of the barrier layer by microgravure coating so that the dry coating amount was 70 mg/ ^m2 , and baked at 200°C in a drying unit. Next, (CL-2) was applied to the obtained layer by microgravure coating so that the dry coating amount was 20 mg/ ^m2 , thereby forming a composite layer consisting of (CL-1) and (CL-2) as the first and the second corrosion prevention treatment layers. This composite layer exhibits corrosion prevention performance by combining the two types of (CL-1) and (CL-2).

Next, the first corrosion prevention layer side of the barrier layer provided with the first and second corrosion prevention layers was attached to the base layer by a dry lamination technique using a polyurethane adhesive (first adhesive layer). Next, the second corrosion prevention layer side of the barrier layer provided with the first and second corrosion prevention layers was attached to a sealant layer (thickness 80 μm) previously formed as a cast film by a dry lamination technique using an epoxy adhesive (second adhesive layer), to produce an exterior material (a laminate of base layer/first adhesive layer/first corrosion prevention layer/barrier layer/second corrosion prevention layer/second adhesive layer/sealant layer). For the formation of the sealant layer, a resin composition for forming a sealant layer having the composition shown in Table 1 was used. The lamination of the barrier layer and the sealant layer was performed by applying an epoxy adhesive to the second corrosion prevention treatment layer side of the barrier layer so that the application amount (mass per unit area) after drying was 3 g/m ² (thickness 3 μm), drying at 80° C. for 1 minute, laminating with the sealant layer, and aging at 120° C. for 3 hours. The numerical values in the column for the sealant layer in Table 1 indicate the content (unit: parts by mass) of each component in the resin composition for forming a sealant layer. The content of each component in the formed sealant layer is equal to the content of each component in the resin composition for forming a sealant layer.

(Examples 2 to 8 and 11 to 13)
Exterior materials of Examples 2 to 8 and 11 to 13 (laminates of substrate layer/first adhesive layer/first corrosion prevention treatment layer/barrier layer/second corrosion prevention treatment layer/second adhesive layer/sealant layer) were prepared in the same manner as in Example 1, except that the composition of the resin composition for forming a sealant layer was changed as shown in Table 1.

(Example 9)
An exterior material of Example 9 (a laminate of substrate layer/first adhesive layer/barrier layer/second adhesive layer/sealant layer) was produced in the same manner as in Example 5, except that the first and second corrosion prevention treatment layers were not provided on the barrier layer.

Example 10
An exterior material of Example 10 (a laminate of substrate layer/first adhesive layer/barrier layer/second adhesive layer/sealant layer) was produced in the same manner as in Example 9, except that a hydrogen sulfide-adsorbing substance was added to the resin composition for forming a sealant layer as shown in Table 1.

(Comparative Examples 1 to 5)
Exterior materials of Comparative Examples 1 to 5 (laminates of substrate layer/first adhesive layer/first corrosion prevention treatment layer/barrier layer/second corrosion prevention treatment layer/second adhesive layer/sealant layer) were prepared in the same manner as in Example 1, except that the composition of the resin composition for forming a sealant layer was changed as shown in Table 1.

[Measurement of heat seal strength]
The exterior material was cut into a size of 120 mm x 60 mm, folded in half so that the sealant layer was on the inside, and the end opposite the folded portion was heat-sealed over a width of 10 mm at the heat-sealing temperature shown in Table 1, 0.5 MPa, and 3 seconds. The heat-sealing temperatures in Comparative Examples 1 to 3 were set lower than those in the other examples in accordance with the composition of the sealant layer. This is because when the exterior materials of Comparative Examples 1 to 3 are heat-sealed at 220°C, the sealant layer flows too much, and the thickness of the sealant layer in the sealed portion becomes too thin, which may cause problems with insulation, etc.

Next, the heat-sealed exterior material was stored at room temperature for 6 hours, and then the longitudinal center of the heat-sealed portion was cut out to a width of 15 mm x length of 30 mm (see FIG. 4) to prepare a sample for measuring heat-seal strength. The sample was left in a test environment at room temperature (25°C) and 150°C for 5 minutes, and then a T-peel test was performed on the heat-sealed portion of the sample under the temperature conditions at a tensile speed of 50 mm/min using a tensile tester (manufactured by Shimadzu Corporation). As a result, the heat-seal strength in a room temperature environment and a high temperature environment was measured. In addition, based on the obtained heat-seal strength, evaluation was performed according to the following criteria. If the evaluation was A or B, it was passed, and if it was C, it was failed. The results are shown in Table 1.
A: Heat seal strength at room temperature and at 150°C is 35N/15mm or more. B: Heat seal strength at room temperature is 35N/15mm or more, or heat seal strength at 150°C is 20N/15mm or more. C: At least one of the heat seal strengths at room temperature and at 150°C is less than 20N/15mm.

[Measurement of _H2S adsorption]
A sample of a sealant layer having an area of 10 ^cm2 and a thickness of 80 μm, formed using a resin composition for forming a sealant layer having the composition shown in Table 1, was enclosed in a 2 L Tedlar (registered trademark) bag. 2 L of hydrogen sulfide gas having a volume of 5 ppm was injected into the bag, and the hydrogen sulfide concentration after leaving it at room temperature (25°C) for 24 hours was measured with a gas detector. The lower the hydrogen sulfide concentration, the better the _H2S adsorption property of the sealant layer. The results are shown in Table 1.

The present disclosure provides an exterior material for a power storage device that has excellent heat resistance and can ensure excellent heat seal strength even in high-temperature environments, and a power storage device using the same.

Reference Signs List 10, 20... exterior material for electricity storage device, 11... base material layer, 12a... first adhesive layer, 12b... second adhesive layer, 13... barrier layer, 14a... first corrosion prevention treatment layer, 14b... second corrosion prevention treatment layer, 15... adhesive resin layer, 16... sealant layer, 50... electricity storage device, 52... battery element, 53... metal terminal.

Claims (8)

An exterior material for an electricity storage device comprising at least a base layer, a barrier layer, and a sealant layer in this order,
the sealant layer comprises: (A) a compound that contains a polyolefin unit and has a melting point of 175° C. or higher or a glass transition temperature of 75° C. or higher; and (B) at least one resin selected from the group consisting of polyethylene-based resins and polypropylene-based resins ;
The component (A) contains a polyamide/polyethylene graft copolymer,
The component (B) contains the polypropylene-based resin,
The exterior material for a storage battery device , wherein the sealant layer further contains a component (C): a compatibilizer having a portion compatible with the polyamide/polyethylene graft copolymer and a portion compatible with the polypropylene-based resin . An exterior material for an electricity storage device comprising at least a base layer, a barrier layer, and a sealant layer in this order,
the sealant layer comprises: (A) a compound that contains a polyolefin unit and has a melting point of 175° C. or higher or a glass transition temperature of 75° C. or higher; and (B) at least one resin selected from the group consisting of polyethylene-based resins and polypropylene-based resins ;
The component (A) comprises an ethylene/cycloolefin copolymer,
The component (B) contains the polypropylene-based resin,
The exterior material for a power storage device , wherein the sealant layer further contains a component (C): a compatibilizer having a portion compatible with the ethylene/cycloolefin copolymer and a portion compatible with the polypropylene-based resin . 3. The exterior material for a storage battery device according to claim 1 , wherein a content of the component (A) in the sealant layer is 5 to 100 parts by mass per 100 parts by mass of the component (B).
. The packaging material for a power storage device according to any one of claims 1 to 3 , wherein a corrosion prevention treatment layer is provided on one or both surfaces of the barrier layer. 5. The packaging material for an electric storage device according to claim 1 , wherein, when the base material layer side of the packaging material for an electric storage device is defined as an outer side and the sealant layer side is defined as an inner side, at least one of layers disposed on the inner side of the barrier layer contains a hydrogen sulfide adsorbing substance. The packaging material for a power storage device according to any one of claims 1 to 5 , wherein the sealant layer has a thickness of 10 to 100 µm. The exterior material for a power storage device according to any one of claims 1 to 6 , which is for an all-solid-state battery. A power storage device main body;
a current extracting terminal extending from the power storage device body;
The exterior packaging material for an electricity storage device according to any one of claims 1 to 7 , which holds the current extracting terminal and houses the electricity storage device body;
A power storage device comprising:

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