WO2023127956A1

WO2023127956A1 - Housing material for power storage device, manufacturing method for housing material, and power storage device

Info

Publication number: WO2023127956A1
Application number: PCT/JP2022/048622
Authority: WO
Inventors: 紘基阿久津; 美帆佐々木
Original assignee: 大日本印刷株式会社
Priority date: 2021-12-28
Filing date: 2022-12-28
Publication date: 2023-07-06
Also published as: JPWO2023127956A1; JP7444341B2

Abstract

Provided is a housing material for a power storage device, the housing material configured from a layered body comprising, in order from the outer side, at least an impact resistance layer, a resin film layer, a barrier layer, and a heat-fusible resin layer.

Description

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

The present disclosure relates to an exterior material for an electricity storage device, a manufacturing method thereof, and an electricity storage device.

Various types of power storage devices have been developed in the past, but in all power storage devices, the exterior material is an indispensable member for sealing the power storage device elements such as electrodes and electrolytes. Conventionally, metal exterior materials have been frequently used as exterior materials for power storage devices.

On the other hand, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., power storage devices are required to have various shapes, as well as to be thinner and lighter. However, conventionally widely used metallic exterior materials for electric storage devices have the drawback that it is difficult to follow the diversification of shapes and that there is a limit to weight reduction.

Therefore, in recent years, a film-like exterior material that can be easily processed into various shapes and that can realize thinness and weight reduction has been developed. Laminates have been proposed (see Patent Document 1, for example).

JP 2008-287971 A

In such a power storage device exterior material, generally, recesses are formed by cold molding using a mold, and power storage device elements such as electrodes and electrolytes are arranged in the spaces formed by the recesses. By heat-sealing the heat-fusible resin layer, an electricity storage device in which the electricity storage device element is housed inside the exterior material for an electricity storage device can be obtained. In order to further increase the energy density of the electricity storage device, it is necessary to form deeper recesses in the exterior material. Also, when the size of the electric storage device is increased, it is necessary to form a deeper concave portion.

However, there is a limit to forming a deep concave portion in an exterior material for an electricity storage device formed of a laminated film. Therefore, there is a demand for an exterior material for an electricity storage device that seals an electricity storage device element in the form of, for example, a bag-like packaging body without molding with a mold or the like.

However, even with a power storage device exterior material that is not molded with a mold, for example, if the size of the power storage device increases, the shock applied to the power storage device exterior material when the power storage device falls will increase, and the power storage device exterior material will be exposed to a larger impact. There is a problem that the exterior material is easily damaged.

Under such circumstances, the main purpose of the present disclosure is to provide an exterior material for an electricity storage device that has excellent drop impact resistance.

The inventors of the present disclosure conducted extensive studies to solve the above problems. As a result, the exterior material for an electric storage device, which is composed of a laminate including, in order from the outside, at least an impact-resistant layer, a resin film layer, a barrier layer, and a heat-fusible resin layer, has excellent drop impact resistance. I found out.

The present disclosure has been completed through further studies based on such new findings. That is, the present disclosure provides inventions in the following aspects.
An exterior material for an electricity storage device, comprising a laminate comprising, in order from the outside, at least an impact-resistant layer, a resin film layer, a barrier layer, and a heat-fusible resin layer.

According to the present disclosure, it is possible to provide an exterior material for an electricity storage device that exhibits excellent drop impact resistance. Further, according to the present disclosure, it is also possible to provide a method for manufacturing the exterior material for an electricity storage device, and an electricity storage device using the exterior material for an electricity storage device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device of the present disclosure; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device of the present disclosure; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device of the present disclosure; 1 is a schematic diagram for explaining an example (gable top type) of the shape of an electricity storage device of the present disclosure; FIG. 1 is a schematic diagram for explaining an example (brick pouch type) of the shape of an electricity storage device of the present disclosure; FIG. 1 is a schematic diagram for explaining an example of the shape of an electricity storage device of the present disclosure (a rectangular parallelepiped shape in which two lid members and one exterior member for an electricity storage device are combined). FIG.

The power storage device exterior material of the present disclosure is characterized by being composed of a laminate including, in order from the outside, at least an impact-resistant layer, a resin film layer, a barrier layer, and a heat-fusible resin layer. With such a configuration, the power storage device exterior material of the present disclosure exhibits excellent drop impact resistance.

The exterior material for an electricity storage device of the present disclosure will be described in detail below. In the present disclosure, the numerical range indicated by "-" means "more than" and "less than". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less. In the numerical ranges described step by step in the present disclosure, upper or lower limits described in a certain numerical range may be replaced with upper or lower limits of other numerical ranges described step by step. Alternatively, the upper limit and upper limit, the upper limit and lower limit, or the lower limit and lower limit, which are separately described, may be combined to form a numerical range. In addition, in the numerical ranges described in the present disclosure, upper or lower limits described in a certain numerical range may be replaced with values shown in Examples.

1. Laminated Structure of Exterior Material for Electric Storage Device The exterior material 10 for an electric storage device of the present disclosure includes, for example, as shown in FIGS. It is composed of a laminate having a flexible resin layer 4 in this order. In the electric storage device exterior material 10, the shock-resistant layer 1 is the outermost layer, and the heat-fusible resin layer 4 is the innermost layer. When an electricity storage device is assembled using the electricity storage device exterior material 10 and an electricity storage device element, the electricity storage device element is placed in a space formed by heat-sealing the heat-sealable resin layer of the electricity storage device exterior material 10 . be accommodated. In the laminate constituting the power storage device exterior material 10 of the present disclosure, the barrier layer 3 is the reference, the heat-fusible resin layer 4 side is inside the barrier layer 3, and the resin film layer 2 side is inside the barrier layer 3. outside.

Since the power storage device exterior material 10 of the present disclosure includes the shock-resistant layer 1, it is not suitable for forming recesses by molding using a mold like the conventional power storage device exterior material. do not have. For this reason, the power storage device exterior material 10 of the present disclosure is preferably used without being subjected to molding by a mold. However, a laminate comprising at least the resin film layer 2, the barrier layer 3, and the heat-fusible resin layer 4 in this order is prepared, and after molding this, the impact-resistant layer 1 is laminated on the resin film layer 2. This does not mean that a mold cannot be used to manufacture the electrical storage device exterior material 10 having recesses formed therein. Specifically, the power storage device exterior material 10 of the present disclosure is a gable top type as shown in FIG. , the upper and lower sides may be of the gable top type.), the brick pouch type as shown in FIG. It is preferable that the power storage device is used so as to form a rectangular parallelepiped electricity storage device in combination with the outer packaging material 10 . In the electricity storage device 20 of FIG. 6 , the electricity storage device element is accommodated in a space formed by the cylindrically formed electricity storage device exterior material 10 and two cover members 11 . The power storage device element is sealed by heat-sealing the heat-sealable resin layer 4 of the power storage device exterior material 10 to the periphery.

For example, as shown in FIGS. 1 to 3, the power storage device exterior material 10 is provided between the impact-resistant layer 1 and the resin film layer 2 for the purpose of improving the adhesion between these layers, if necessary. may have an adhesive layer 5 on each side. For example, as shown in FIGS. 2 and 3, an adhesive layer 6 is optionally provided between the resin film layer 2 and the barrier layer 3 for the purpose of enhancing adhesion between these layers. You may have For example, as shown in FIG. 3, an adhesive layer 7 is optionally provided between the barrier layer 3 and the heat-sealable resin layer 4 for the purpose of enhancing the adhesion between these layers. may be

The thickness of the laminate constituting the power storage device exterior material 10 is not particularly limited. is mentioned. The thickness of the laminate constituting the power storage device exterior material 10 is preferably about 60 μm or more, about 80 μm or more, about 100 μm or more, about 150 μm or more, about 180 μm or more, and the like. Further, the preferred range of the laminate constituting the power storage device exterior material 10 is, for example, about 60 to 300 μm, about 60 to 250 μm, about 60 to 200 μm, about 60 to 190 μm, about 80 to 300 μm, and about 80 to 250 μm. , about 80 to 200 μm, about 80 to 190 μm, about 100 to 300 μm, about 100 to 250 μm, about 100 to 200 μm, about 100 to 190 μm, about 150 to 300 μm, about 150 to 250 μm, about 150 to 200 μm, about 150 to 190 μm , about 180 to 300 μm, about 180 to 250 μm, about 180 to 200 μm, and about 180 to 190 μm.

In the electrical storage device exterior material 10, the impact resistant layer 1, the adhesive layer 5 provided as necessary, the resin film layer 2, and, if necessary, the thickness (total thickness) of the laminate constituting the electrical storage device exterior material 10 The ratio of the total thickness of the adhesive layer 6 provided as required, the barrier layer 3, the adhesive layer 7 provided as required, and the heat-fusible resin layer 4 is preferably 90% or more, more preferably 95%. % or more, more preferably 98% or more. As a specific example, the power storage device exterior material 10 of the present disclosure includes an impact-resistant layer 1, an adhesive layer 5, a resin film layer 2, an adhesive layer 6, a barrier layer 3, an adhesive layer 7, and a heat-fusible resin. When the layer 4 is included, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the power storage device exterior material 10 is preferably 90% or more, more preferably 95% or more. , more preferably 98% or more. In addition, the power storage device exterior material 10 of the present disclosure is a laminate including the shock-resistant layer 1, the adhesive layer 5, the resin film layer 2, the adhesive layer 6, the barrier layer 3, and the heat-fusible resin layer 4. In some cases, the ratio of the total thickness of each of these layers to the thickness (total thickness) of the laminate constituting the power storage device exterior material 10 is, for example, 80% or more, preferably 90% or more, and more preferably 95% or more. , and more preferably 98% or more.

2. Each layer forming the exterior material for the electricity storage device [shock resistant layer 1]
The impact-resistant layer 1 is a layer that functions as a cushion that imparts excellent drop impact resistance to the power storage device exterior material 10 of the present disclosure. The shock-resistant layer 1 preferably constitutes the outermost layer of the power storage device exterior material 10 .

The impact-resistant layer 1 may be a layer that imparts impact resistance to the power storage device exterior material 10, and may be a fibrous base material such as paper, a polycarbonate-based resin, a polyimide-based resin, a polyamide-based resin, or a polyamide-imide-based material. It can be composed of resin base materials such as resins, polyester resins, polyolefin resins and polystyrene resins, and rubber base materials such as butadiene rubber and natural rubber.

When the impact resistant layer 1 is a resin substrate or a rubber substrate, the tensile modulus of the impact resistant layer 1 is preferably 0.1 GPa or more, more preferably 0.1 to 10 GPa.

The impact-resistant layer 1 is preferably a layer (fibrous base material layer) in which a base material made of fibrous material is provided in layers. The fibrous base material layer is composed of, for example, paper, nonwoven fabric, woven fabric, wood material, etc., preferably paper or nonwoven fabric, and more preferably paper. In the present disclosure, paper is a thin piece made by agglutinating fibers such as plants and synthetic resins, and is mainly composed of plant fibers. In addition to paper, paper containing fibrous inorganic materials is also included. In addition, nonwoven fabric is a fabric made by mechanically, chemically, and thermally treating a fiber sheet without going through the form of yarn, and bonding it with an adhesive or the fusing power of the fiber itself. fiber). A woven fabric is a fabric made of woven fibers. Wood materials include, for example, wood veneer, plywood, laminated wood, medium-density fiberboard, hard fiberboard, and the like.

The material constituting the fibrous base material layer is not particularly limited, and natural fibers, synthetic fibers (chemical fibers), etc. can be used.

When the fibrous base material layer is made of paper, the material constituting the paper is not particularly limited. ), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), deinked pulp (DIP), etc. Among them, pulp materials derived from softwood are particularly preferred. Waste paper pulp such as waste newspaper, waste magazine paper, waste corrugated board, and waste deinked paper can also be used as the pulp material. Moreover, the paper may contain a mixture of the pulp material and synthetic fibers such as rayon, polyamide, polyimide, polyester, polyolefin, and polyvinyl alcohol. As a specific example of the paper, base paper for liquid paper containers is preferably exemplified.

In addition, when the fibrous base material layer is composed of nonwoven fabric or woven fabric, the material constituting the nonwoven fabric or woven fabric is not particularly limited. chemical fibers such as vinylon and aramid fibers; and natural fibers such as cotton, wool, hemp, silk and pulp.

The material constituting the shock-resistant layer 1 may be of only one type, or may be of two or more types.

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

Although the basis weight (basis weight) of the impact-resistant layer 1 is not particularly limited, it is preferably 100 g/m ² or more, more preferably 150 g/m 2 or more, and more preferably 150 g/m ² or more from the viewpoint of more suitably exhibiting the effects of the present disclosure. It is preferably 200 g/m ² or more, more preferably 1000/m ² or less, more preferably 600/m ² or ^less , still more preferably 500/m 2 or less. about ² , about 100-600/ ^m2 , about 100-500/ ^m2 , about 150-1000/ ^m2 , about 150-600/ ^m2 , about 150-500/ ^m2 , about 200-1000/ ^m2 , about 200 to 600/m ² , and about 200 to 500.

[Adhesive layer 5]
In the power storage device exterior material of the present disclosure, the adhesive layer 5 is a layer provided between the impact-resistant layer 1 and the resin film layer 2 as necessary for the purpose of increasing the adhesion between them. .

The adhesive layer 5 is made of an adhesive capable of bonding the impact-resistant layer 1 and the resin film layer 2 together. The adhesive used to form the adhesive layer 5 is not limited, but may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, and the like. Further, it may be a two-liquid curing adhesive (two-liquid adhesive), a one-liquid curing adhesive (one-liquid adhesive), or a resin that does not involve a curing reaction. Further, the adhesive layer 5 may be a single layer or multiple layers.

Specific examples of the adhesive component contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; polyether; polyurethane; epoxy resin; Phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymerized polyamides; polyolefin resins such as polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimide; polycarbonate; amino resin such as urea resin and melamine resin; rubber such as chloroprene rubber, nitrile rubber and styrene-butadiene rubber; These adhesive components may be used singly or in combination of two or more. Among these adhesive components, polyurethane adhesives are preferred. In addition, an appropriate curing agent can be used in combination with these adhesive component resins to increase the adhesive strength. The curing agent is selected from among polyisocyanates, polyfunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, etc., depending on the functional groups of the adhesive component.

Examples of polyurethane adhesives include polyurethane adhesives containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. Preferably, a two-component curing type polyurethane adhesive is used in which a polyol such as polyester polyol, polyether polyol, or acrylic polyol is used as the first agent and an aromatic or aliphatic polyisocyanate is used as the second agent. Examples of polyurethane adhesives include polyurethane adhesives containing an isocyanate compound and a polyurethane compound obtained by reacting a polyol compound and an isocyanate compound in advance. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound and an isocyanate compound in advance and a polyol compound. Examples of polyurethane adhesives include polyurethane adhesives obtained by reacting a polyurethane compound obtained by reacting a polyol compound and an isocyanate compound in advance with moisture in the air and curing the compound. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in a side chain in addition to the terminal hydroxyl group of the repeating unit. Examples of the second agent include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate. (MDI), naphthalene diisocyanate (NDI), and the like. In addition, polyfunctional isocyanate-modified products of one or more of these diisocyanates are also included. Moreover, a polymer (for example, a trimer) can also be used as a polyisocyanate compound. Such multimers include adducts, biurets, nurates and the like. Since the adhesive layer 5 is formed of a polyurethane adhesive, the exterior material for an electric storage device is endowed with excellent electrolytic solution resistance, and peeling of the resin film layer 2 is suppressed even if the electrolytic solution adheres to the side surface. .

In addition, the adhesive layer 5 may contain other components as long as they do not interfere with adhesion, and may contain colorants, thermoplastic elastomers, tackifiers, fillers, and the like. Since the adhesive layer 5 contains a coloring agent, the power storage device exterior material can be colored. Known substances such as pigments and dyes can be used as the colorant. In addition, only one type of colorant may be used, or two or more types may be mixed and used.

The type of pigment is not particularly limited as long as it does not impair the adhesiveness of the adhesive layer 5. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments. Examples of pigments include carbon black, titanium oxide, cadmium, lead, chromium oxide, and iron pigments, as well as fine powder of mica and fish scale foil.

Among the coloring agents, carbon black is preferable, for example, in order to make the external appearance of the exterior material for a power storage device black.

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

The content of the pigment in the adhesive layer 5 is not particularly limited as long as the power storage device exterior material is colored, and is, for example, about 5 to 60% by mass, preferably 10 to 40% by mass.

The thickness of the adhesive layer 5 is not particularly limited as long as the impact-resistant layer 1 and the resin film layer 2 can be adhered, but is, for example, about 1 μm or more, or about 2 μm or more. Moreover, the thickness of the adhesive layer 5 is, for example, about 10 μm or less, or about 5 μm or less. Moreover, the preferable range of the thickness of the adhesive layer 5 is about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

When the impact-resistant layer is a fibrous base material layer, the adhesive layer 5 is usually impregnated in the gaps of the fibrous base material layer. From the viewpoint of making the electric storage device exterior material, the adhesive layer 5 is preferably not exposed in the outermost layer of the electrical storage device exterior material, and the fibrous base material layer preferably constitutes the outermost layer of the electrical storage device exterior material.

[Resin film layer 2]
In the present disclosure, the resin film layer 2 is a layer provided for the purpose of exhibiting a function as a base material of an exterior material for an electric storage device. The resin film layer 2 is located outside the intermediate barrier layer 3 in the exterior material for an electric storage device.

The material forming the resin film layer 2 is not particularly limited as long as it functions as a base material, that is, at least has insulating properties. The resin film layer 2 can be formed using, for example, a resin, and the resin may contain additives described later.

When the resin film layer 2 is formed of resin, the resin film layer 2 may be, for example, a resin film formed of resin, or may be formed by applying resin. The resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially stretched films and biaxially stretched films, with biaxially stretched films being preferred. Examples of stretching methods for forming a biaxially stretched film include successive biaxial stretching, inflation, and simultaneous biaxial stretching. Methods for applying the resin include a roll coating method, a gravure coating method, an extrusion coating method, and the like.

Examples of the resin forming the resin film layer 2 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, phenolic resin, and modified products of these resins. Further, the resin forming the resin film layer 2 may be a copolymer of these resins or a modified product of the copolymer. Furthermore, it may be a mixture of these resins.

Among these, the resin forming the resin film layer 2 preferably includes polyester and polyamide.

Specific examples of polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester. Examples of copolyester include copolyester having ethylene terephthalate as a main repeating unit. Specifically, copolymer polyester polymerized with ethylene isophthalate with ethylene terephthalate as the main repeating unit (hereinafter abbreviated after polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate), polyethylene (terephthalate/decanedicarboxylate), and the like. These polyesters may be used singly or in combination of two or more.

Further, as the polyamide, specifically, aliphatic polyamide such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, copolymer of nylon 6 and nylon 66; terephthalic acid and / or isophthalic acid Hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamide such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) containing structural units derived from, polyamide MXD6 (polymetallic Polyamides containing aromatics such as silylene adipamide); alicyclic polyamides such as polyamide PACM6 (polybis(4-aminocyclohexyl)methane adipamide); Copolymerized polyamides, polyesteramide copolymers and polyetheresteramide copolymers which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and polyamides such as these copolymers. These polyamides may be used singly or in combination of two or more.

The resin film layer 2 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, and preferably includes at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film. It is more preferable to include at least one of an oriented polyethylene terephthalate film, an oriented polybutylene terephthalate film, an oriented nylon film, and an oriented polypropylene film, and a biaxially oriented polyethylene terephthalate film, a biaxially oriented polybutylene terephthalate film, and a biaxially oriented nylon film. , biaxially oriented polypropylene film.

The resin film layer 2 may be a single layer, or may be composed of two or more layers. When the resin film layer 2 is composed of two or more layers, the resin film layer 2 may be a laminate obtained by laminating resin films with an adhesive or the like, or may be formed by co-extrusion of resin to form two or more layers. It may also be a laminate of resin films. A laminate of two or more resin films formed by coextrusion of resin may be used as the resin film layer 2 without being stretched, or may be formed as the resin film layer 2 by being uniaxially or biaxially stretched.

In the resin film layer 2, specific examples of a laminate of two or more layers of resin films include a laminate of a polyester film and a nylon film, a laminate of nylon films of two or more layers, and a laminate of polyester films of two or more layers. etc., preferably a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more layers of stretched nylon films, and a laminate of two or more layers of stretched polyester films. For example, when the resin film layer 2 is a laminate of two resin films, a laminate of polyester resin films and polyester resin films, a laminate of polyamide resin films and polyamide resin films, or a laminate of polyester resin films and polyamide resin films. A laminate is preferred, and a laminate of polyethylene terephthalate film and polyethylene terephthalate film, a laminate of nylon film and nylon film, or a laminate of polyethylene terephthalate film and nylon film is more preferred. In addition, the polyester resin is resistant to discoloration when, for example, an electrolytic solution adheres to its surface. It is preferably located in the outermost layer.

When the resin film layer 2 is a laminate of two or more layers of resin films, the two or more layers of resin films may be laminated via an adhesive. Preferred adhesives are the same as those exemplified for the adhesive layer 5 described above. The method for laminating two or more layers of resin films is not particularly limited, and known methods can be employed. Examples thereof include dry lamination, sandwich lamination, extrusion lamination, thermal lamination, and the like. A lamination method is mentioned. When laminating by dry lamination, it is preferable to use a polyurethane adhesive as the adhesive. At this time, the thickness of the adhesive is, for example, about 2 to 5 μm. Alternatively, an anchor coat layer may be formed on the resin film and laminated. The anchor coat layer includes the same adhesives as those exemplified for the adhesive layer 6 described later. At this time, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

Additives such as flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present on at least one of the surface and the interior of the resin film layer 2 . Only one type of additive may be used, or two or more types may be mixed and used.

The thickness of the resin film layer 2 is not particularly limited as long as it functions as a base material, but it is, for example, about 3 to 50 μm, preferably about 10 to 35 μm. When the resin film layer 2 is a laminate of two or more resin films, the thickness of each resin film constituting each layer is preferably about 2 to 25 μm. Further, when the resin film layer 2 has a multilayer structure consisting of a biaxially stretched polyester resin layer, an adhesive layer, and a biaxially stretched polyamide resin layer in order from the outside, the thickness of the resin film layer 2 is 25 to 35 μm. about 35 to 45 μm.

[Adhesive layer 6]
In the power storage device exterior material of the present disclosure, the adhesive layer 6 is a layer provided between the resin film layer 2 and the barrier layer 3 as necessary for the purpose of enhancing the adhesiveness between them.

The adhesive layer 6 is made of an adhesive capable of bonding the resin film layer 2 and the barrier layer 3 together. The adhesive used to form the adhesive layer 6 is not limited, but may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, and the like. Further, it may be a two-liquid curing adhesive (two-liquid adhesive), a one-liquid curing adhesive (one-liquid adhesive), or a resin that does not involve a curing reaction. Further, the adhesive layer 6 may be a single layer or multiple layers.

Examples of the adhesive component contained in the adhesive used to form the adhesive layer 6 are the same as those exemplified for the adhesive layer 5 .

In addition, the adhesive layer 6 may contain other components as long as they do not interfere with adhesion, and may contain colorants, thermoplastic elastomers, tackifiers, fillers, and the like. Since the adhesive layer 6 contains a coloring agent, the power storage device exterior material can be colored. Known substances such as pigments and dyes can be used as the colorant. In addition, only one type of colorant may be used, or two or more types may be mixed and used.

The type of pigment is not particularly limited as long as it does not impair the adhesiveness of the adhesive layer 6. Examples of the organic pigment are the same as those exemplified for the adhesive layer. Among the coloring agents, carbon black is preferable, for example, in order to make the external appearance of the exterior material for an electric storage device black. The average particle size of the pigment is not particularly limited, and is, for example, approximately 0.05 to 5 μm, preferably approximately 0.08 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction/scattering particle size distribution analyzer.

The content of the pigment in the adhesive layer 6 is not particularly limited as long as the power storage device exterior material is colored, and is, for example, about 5 to 60% by mass, preferably 10 to 40% by mass.

The thickness of the adhesive layer 6 is not particularly limited as long as the resin film layer 2 and the barrier layer 3 can be adhered, but is, for example, about 1 μm or more, or about 2 μm or more. Also, the thickness of the adhesive layer 6 is, for example, about 10 μm or less, or about 5 μm or less. Moreover, the preferable range of the thickness of the adhesive layer 6 is about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

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

Examples of the barrier layer 3 include a metal foil, vapor deposition film, and resin layer having barrier properties. Examples of vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Polymers containing fluoroethylene (TFE) as a main component, polymers having a fluoroalkyl group, fluorine-containing resins such as polymers containing fluoroalkyl units as a main component, and ethylene vinyl alcohol copolymers. The barrier layer 3 may also include a resin film provided with at least one of these deposited films and resin layers. A plurality of barrier layers 3 may be provided. The barrier layer 3 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include aluminum alloys, stainless steels, titanium steels, and steel plates. When used as metal foils, at least one of aluminum alloy foils and stainless steel foils is included. is preferred.

The aluminum alloy foil is more preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy or the like, from the viewpoint of improving the drop impact resistance of the exterior material for an electricity storage device, and an aluminum alloy foil containing iron. is preferred. In the aluminum alloy foil containing iron (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. When the iron content is 9.0% by mass or less, it is possible to obtain an exterior material for an electricity storage device that is more excellent in flexibility. As the soft aluminum alloy foil, for example, an aluminum alloy having a composition specified by JIS H4160: 1994 A8021H-O, JIS H4160: 1994 A8079H-O, JIS H4000: 2014 A8021P-O, or JIS H4000: 2014 A8079P-O foil. Moreover, silicon, magnesium, copper, manganese, etc. may be added as needed. Moreover, softening can be performed by annealing treatment or the like.

In addition, examples of stainless steel foils include austenitic, ferritic, austenitic/ferritic, martensitic, and precipitation hardened stainless steel foils. Furthermore, from the viewpoint of providing an exterior material for an electricity storage device having excellent drop impact resistance, the stainless steel foil is preferably made of austenitic stainless steel.

Specific examples of the austenitic stainless steel that constitutes the stainless steel foil include SUS304, SUS301, SUS316L, etc. Among these, SUS304 is particularly preferable.

The thickness of the barrier layer 3 is not particularly limited as long as it exhibits at least a function as a barrier layer that suppresses penetration of moisture, and is 40 μm or more. The thickness of the barrier layer is preferably about 45 μm or more, more preferably about 50 μm or more, still more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 150 μm or less, and still more preferably about 100 μm or less. , more preferably about 65 μm or less, and preferable ranges are about 40 to 200 μm, about 40 to 150 μm, about 40 to 100 μm, about 40 to 65 μm, about 45 to 200 μm, about 45 to 150 μm, about 45 to 100 μm, About 45 to 65 μm, about 50 to 200 μm, about 50 to 150 μm, about 50 to 100 μm, about 50 to 65 μm, about 55 to 200 μm, about 55 to 150 μm, about 55 to 100 μm, and about 55 to 65 μm.

Also, when the barrier layer 3 is a metal foil, it is preferable that at least the surface opposite to the resin film layer is provided with a corrosion-resistant film in order to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion resistant coating on both sides. Here, the corrosion-resistant film includes, for example, hydrothermal transformation treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment such as nickel and chromium, and corrosion prevention treatment such as applying a coating agent to the surface of the barrier layer. It is a thin film that provides corrosion resistance (for example, acid resistance, alkali resistance, etc.) to the barrier layer. The corrosion-resistant film specifically means a film that improves the acid resistance of the barrier layer (acid-resistant film), a film that improves the alkali resistance of the barrier layer (alkali-resistant film), and the like. As the treatment for forming the corrosion-resistant film, one type may be performed, or two or more types may be used in combination. Also, not only one layer but also multiple layers can be used. Furthermore, among these treatments, the hydrothermal transformation treatment and the anodizing treatment are treatments in which the surface of the metal foil is dissolved with a treating agent to form a metal compound having excellent corrosion resistance. These treatments are sometimes included in the definition of chemical conversion treatment. When the barrier layer 3 has a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

The corrosion-resistant coating prevents delamination between the barrier layer (e.g., aluminum alloy foil) and the resin film layer, and prevents dissolution and corrosion of the barrier layer surface by the hydrogen fluoride generated by the reaction between the electrolyte and moisture. When the barrier layer is an aluminum alloy foil, it prevents the aluminum oxide present on the barrier layer surface from dissolving and corroding, and improves the adhesiveness (wettability) of the barrier layer surface to form a resin film at the time of heat sealing. The effect of preventing delamination between a layer and a barrier layer and preventing delamination between a resin film layer and a barrier layer is shown.

Various types of corrosion-resistant coatings formed by chemical conversion treatment are known, and are mainly composed of at least one of phosphates, chromates, fluorides, triazinethiol compounds, and rare earth oxides. Corrosion-resistant coatings containing Examples of chemical conversion treatments using phosphate and chromate include chromic acid chromate treatment, phosphoric acid chromate treatment, phosphoric acid-chromate treatment, and chromate treatment. Examples of compounds include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromium acetyl acetate, chromium chloride, potassium chromium sulfate, and the like. Phosphorus compounds used for these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid, and the like. Examples of the chromate treatment include etching chromate treatment, electrolytic chromate treatment, coating-type chromate treatment, etc., and coating-type chromate treatment is preferred. In this coating-type chromate treatment, at least the inner layer side surface of the barrier layer (for example, aluminum alloy foil) is first subjected to a well-known method such as an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activation method, or the like. After degreasing by a treatment method, metal phosphate such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, Zn (zinc) phosphate is applied to the degreased surface. A processing solution mainly composed of a salt and a mixture of these metal salts, a processing solution mainly composed of a non-metal phosphate salt and a mixture of these non-metal salts, or a mixture of these and a synthetic resin. This is a treatment in which a treatment liquid composed of a mixture is applied by a well-known coating method such as a roll coating method, a gravure printing method, or an immersion method, and then dried. Various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents can be used as the treatment liquid, and water is preferred. In addition, the resin component used at this time includes polymers such as phenolic resins and acrylic resins. and the chromate treatment used. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained singly or in any combination of two or more. good too. The acrylic resin is polyacrylic acid, acrylic acid methacrylic acid ester copolymer, acrylic acid maleic acid copolymer, acrylic acid styrene copolymer, or derivatives thereof such as sodium salts, ammonium salts, and amine salts. is preferred. In particular, derivatives of polyacrylic acid such as ammonium salt, sodium salt or amine salt of polyacrylic acid are preferred. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. Further, the acrylic resin is preferably a copolymer of acrylic acid and dicarboxylic acid or dicarboxylic anhydride, and the ammonium salt, sodium salt, Alternatively, it is also preferably an amine salt. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

In general formulas (1) to (4), X represents a hydrogen atom, hydroxy group, alkyl group, hydroxyalkyl group, allyl group or benzyl group. R ¹ and R ² are the same or different and represent a hydroxy group, an alkyl group or a hydroxyalkyl group. Examples of alkyl groups represented by X, R ¹ and R ² in general formulas (1) to (4) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, A linear or branched alkyl group having 1 to 4 carbon atoms such as a tert-butyl group can be mentioned. Examples of hydroxyalkyl groups represented by X, R ¹ and R ² include hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3- A straight or branched chain having 1 to 4 carbon atoms substituted with one hydroxy group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group and 4-hydroxybutyl group An alkyl group is mentioned. In general formulas (1) to (4), the alkyl groups and hydroxyalkyl groups represented by X, R ¹ and R ² may be the same or different. In general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having repeating units represented by formulas (1) to (4) is, for example, preferably about 500 to 1,000,000, more preferably about 1,000 to 20,000. more preferred. The aminated phenol polymer is produced, for example, by polycondensing a phenol compound or naphthol compound and formaldehyde to produce a polymer comprising repeating units represented by the general formula (1) or general formula (3), followed by formaldehyde. and an amine (R ¹ R ² NH) to introduce a functional group (--CH ₂ NR ¹ R ² ) into the polymer obtained above. An aminated phenol polymer is used individually by 1 type or in mixture of 2 or more types.

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

As an example of the corrosion-resistant film, fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, and barium sulfate are dispersed in phosphoric acid, which is applied to the surface of the barrier layer. C. or more, and those formed by performing baking processing are mentioned.

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

The analysis of the composition of the corrosion-resistant coating can be performed using, for example, time-of-flight secondary ion mass spectrometry.

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

The thickness of the corrosion-resistant coating is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably 1 nm to 100 nm, from the viewpoint of cohesion of the coating and adhesion to the barrier layer and the heat-sealable resin layer. about 1 nm to 50 nm, more preferably about 1 nm to 50 nm. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron beam energy loss spectroscopy. By analysis of the composition of the corrosion-resistant coating using time-of-flight secondary ion mass spectrometry, for example, secondary ions composed of Ce, P and O (for example, at least one of Ce ₂ PO ₄ ⁺ and CePO ₄ ⁻ species) and, for example, secondary ions composed of Cr, P, and O (eg, at least one of CrPO ₂ ⁺ and CrPO ₄ ⁻ ) are detected.

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

[Heat-fusible resin layer 4]
In the power storage device exterior material of the present disclosure, the heat-fusible resin layer 4 corresponds to the innermost layer, and has the function of sealing the power storage device element by heat-sealing the heat-fusible resin layers to each other when assembling the power storage device. It is a layer (sealant layer) that exhibits

The resin constituting the heat-fusible resin layer 4 is not particularly limited as long as it is heat-fusible, but resins containing polyolefin skeletons such as polyolefins and acid-modified polyolefins are preferable. The inclusion of a polyolefin skeleton in the resin constituting the heat-fusible resin layer 4 can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like. Further, when the resin constituting the heat-fusible resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near wavenumbers of 1760 cm ⁻¹ and 1780 cm ⁻¹ . When the heat-fusible resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected when measured by infrared spectroscopy. However, if the degree of acid denaturation is low, the peak may be too small to be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

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

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

Acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of polyolefin with an acid component. As the acid-modified polyolefin, the above polyolefin, a copolymer obtained by copolymerizing the above polyolefin with a polar molecule such as acrylic acid or methacrylic acid, or a polymer such as crosslinked polyolefin can be used. Examples of acid components used for acid modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride and itaconic anhydride, and anhydrides thereof.

The acid-modified polyolefin may be an acid-modified cyclic polyolefin. Acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin in place of the acid component, or by block-polymerizing or graft-polymerizing the acid component to the cyclic polyolefin. be. The acid-modified cyclic polyolefin is the same as described above. The acid component used for acid modification is the same as the acid component used for modification of polyolefin.

Preferable acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylene modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefin, and maleic anhydride-modified polypropylene.

The heat-fusible resin layer 4 may be formed of one type of resin alone, or may be formed of a blend polymer in which two or more types of resin are combined. Furthermore, the heat-fusible resin layer 4 may be formed of only one layer, or may be formed of two or more layers of the same or different resins.

The thickness of the heat-fusible resin layer 4 is not particularly limited as long as the heat-fusible resin layers are heat-sealed to each other to exhibit the function of sealing the electricity storage device element, but for example, it is about 100 μm or less, preferably about 100 μm or less. About 85 μm or less, more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 7 described later is 10 μm or more, the thickness of the heat-fusible resin layer 4 is preferably about 85 μm or less, more preferably about 15 to 45 μm. When the thickness of the adhesive layer 7 described later is less than 10 μm or when the adhesive layer 7 is not provided, the thickness of the heat-fusible resin layer 4 is preferably about 20 μm or more, more preferably 35 to 85 μm. degree.

[Adhesion layer 7]
In the power storage device exterior material of the present disclosure, the adhesive layer 7 is provided between the barrier layer 3 (or the corrosion-resistant film) and the heat-fusible resin layer 4 as necessary in order to firmly bond them. It is a layer that can be

The adhesive layer 7 is made of a resin capable of bonding the barrier layer 3 and the heat-fusible resin layer 4 together. As the resin used for forming the adhesive layer 7, for example, the same adhesives as those exemplified for the adhesive layer 6 can be used. Further, from the viewpoint of firmly bonding the adhesive layer 7 and the heat-fusible resin layer 4, it is preferable that the resin used for forming the adhesive layer 7 contains a polyolefin skeleton. Polyolefins and acid-modified polyolefins exemplified for the resin layer 4 can be used. On the other hand, from the viewpoint of firmly bonding the barrier layer 3 and the adhesive layer 7, the adhesive layer 7 preferably contains an acid-modified polyolefin. Acid-modified components include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid and adipic acid, their anhydrides, acrylic acid and methacrylic acid. Maleic acid is most preferred. Moreover, from the viewpoint of heat resistance of the exterior material for an electric storage device, the olefin component is preferably a polypropylene-based resin, and the adhesive layer 7 most preferably contains maleic anhydride-modified polypropylene.

Whether or not the resin forming the adhesive layer 7 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. Further, the fact that the resin constituting the adhesive layer 7 contains ^an acid-modified polyolefin means that, for example, when the maleic anhydride-modified polyolefin is measured by infrared spectroscopy ^, anhydrous A peak derived from maleic acid is detected. However, if the degree of acid denaturation is low, the peak may be too small to be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Furthermore, from the viewpoint of durability such as heat resistance and content resistance of the exterior material for an electric storage device and reduction in thickness, the adhesive layer 7 is preferably a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. more preferred. Preferred examples of the acid-modified polyolefin include those mentioned above.

Further, the adhesive layer 7 is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. A cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group is particularly preferred. Moreover, the adhesive layer 7 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. As the polyester, for example, an ester resin produced by a reaction between an epoxy group and a maleic anhydride group, and an amide ester resin produced by a reaction between an oxazoline group and a maleic anhydride group are preferable. In addition, when an unreacted product of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remains in the adhesive layer 7, the presence of the unreacted product can be detected by, for example, infrared spectroscopy, It can be confirmed by a method selected from Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

In addition, from the viewpoint of further increasing the adhesion between the barrier layer 3 and the adhesive layer 7, the adhesive layer 7 contains at least It is preferably a cured product of a resin composition containing one curing agent. The curing agent having a heterocyclic ring includes, for example, a curing agent having an oxazoline group, a curing agent having an epoxy group, and the like. Moreover, the curing agent having a C═N bond includes a curing agent having an oxazoline group, a curing agent having an isocyanate group, and the like. Further, the curing agent having a C—O—C bond includes a curing agent having an oxazoline group, a curing agent having an epoxy group, and the like. The adhesive layer 7 is a cured product of a resin composition containing these curing agents, for example, gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF). -SIMS) and X-ray photoelectron spectroscopy (XPS).

The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively increasing the adhesion between the barrier layer 3 and the adhesive layer 7, polyfunctional isocyanate compounds are preferred. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymerization and nurate compounds, mixtures thereof, copolymers with other polymers, and the like. In addition, adducts, biurets, isocyanurates and the like are included.

The content of the compound having an isocyanate group in the adhesive layer 7 is preferably in the range of 0.1 to 50% by mass, more preferably 0.5 to 40% by mass, in the resin composition constituting the adhesive layer 7. A range is more preferred. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 7 can be effectively improved.

The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of compounds having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Moreover, as a commercial item, the Epocross series by Nippon Shokubai Co., Ltd. etc. are mentioned, for example.

The ratio of the compound having an oxazoline group in the adhesive layer 7 is preferably in the range of 0.1 to 50% by mass, more preferably 0.5 to 40% by mass, in the resin composition constituting the adhesive layer 7. is more preferable. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 7 can be effectively improved.

Examples of compounds having an epoxy group include epoxy resins. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure with epoxy groups present in the molecule, and known epoxy resins can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, still more preferably about 200 to 800. In the present disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard sample.

Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F-type glycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, and the like. is mentioned. An epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more types.

The ratio of the epoxy resin in the adhesive layer 7 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass, in the resin composition constituting the adhesive layer 7. is more preferred. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 7 can be effectively improved.

The polyurethane is not particularly limited, and known polyurethanes can be used. The adhesive layer 7 may be, for example, a cured product of two-component curing type polyurethane.

The proportion of polyurethane in the adhesive layer 7 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass, in the resin composition constituting the adhesive layer 7. more preferred. As a result, the adhesion between the barrier layer 3 and the adhesive layer 7 can be effectively enhanced in an atmosphere containing a component that induces corrosion of the barrier layer, such as an electrolytic solution.

In addition, when the adhesive layer 7 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin. , the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

The adhesive layer 7 may contain a modifier having a carbodiimide group.

The thickness of the adhesive layer 7 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 5 μm or less. Also, the thickness of the adhesive layer 7 is preferably about 0.1 μm or more and about 0.5 μm or more. The thickness range of the adhesive layer 7 is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, and about 0.1 to 5 μm. , about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, and about 0.5 to 5 μm. More specifically, in the case of the adhesive exemplified for the adhesive layer 6 or the cured product of acid-modified polyolefin and a curing agent, the thickness is preferably about 1 to 10 μm, more preferably about 1 to 5 μm. In the case of using the resin exemplified for the heat-fusible resin layer 4, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When the adhesive layer 7 is the adhesive exemplified for the adhesive layer 6 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, for example, the resin composition is applied and cured by heating or the like. Thus, the adhesive layer 7 can be formed. Further, when using the resin exemplified for the heat-fusible resin layer 4, the heat-fusible resin layer 4 and the adhesive layer 7 can be formed by extrusion molding, for example. When the heat-fusible resin layer 4 and the adhesive layer 7 are formed by co-extrusion molding, the lower limits of the total thickness of the heat-fusible resin layer 4 and the adhesive layer 7 are 35 μm, 55 μm, and 75 μm. The upper limit is 45 μm, 65 μm, 85 μm, and the numerical range is preferably 35 to 45 μm, 35 to 65 μm, 35 to 85 μm, 55 to 65 μm, 55 to 85 μm, 75 to 85 μm.

3. Method for producing an exterior material for an electricity storage device The method for producing an exterior material for an electricity storage device is not particularly limited as long as a laminate obtained by laminating each layer included in the exterior material for an electricity storage device of the present invention is obtained. A step of obtaining a laminate comprising at least an impact-resistant layer, a resin film layer, a barrier layer, and a heat-fusible resin layer is provided.

An example of the method for manufacturing the exterior material for an electricity storage device of the present invention is as follows. First, a laminate (hereinafter sometimes referred to as "laminate A") is formed by laminating the resin film layer 2, the adhesive layer 6, and the barrier layer 3 in this order. Specifically, the laminate A is formed by coating an adhesive used for forming the adhesive layer 6 on the resin film layer 2 or on the barrier layer 3 whose surface is chemically treated as necessary, by gravure coating, It can be performed by a dry lamination method in which the barrier layer 3 or the resin film layer 2 is laminated and the adhesive layer 6 is cured after coating and drying by a coating method such as a roll coating method.

Next, the heat-fusible resin layer 4 is laminated on the barrier layer 3 of the laminate A. When the heat-fusible resin layer 4 is directly laminated on the barrier layer 3, the heat-fusible resin layer 4 is laminated on the barrier layer 3 of the laminate A by a method such as thermal lamination or extrusion lamination. do it. When the adhesive layer 7 is provided between the barrier layer 3 and the heat-fusible resin layer 4, for example, (1) the adhesive layer 7 and the heat-fusible resin layer are placed on the barrier layer 3 of the laminate A. 4 (co-extrusion lamination method, tandem lamination method); A method of laminating on the barrier layer 3 of the laminate A by a thermal lamination method, or forming a laminate in which an adhesive layer 7 is laminated on the barrier layer 3 of the laminate A, and laminating this with the heat-fusible resin layer 4 by a thermal lamination method Lamination method (3) While pouring the melted adhesive layer 7 between the barrier layer 3 of the laminate A and the heat-fusible resin layer 4 formed into a sheet in advance, the adhesive layer 7 is interposed. (4) coating the barrier layer 3 of the laminate A with an adhesive for forming the adhesive layer 7 in solution, A drying method, a baking method, or the like is used to laminate the adhesive layer 7 , and a heat-fusible resin layer 4 that has been formed into a sheet in advance is laminated on the adhesive layer 7 .

Next, the impact-resistant layer 1 is laminated on the surface of the resin film layer 2 opposite to the barrier layer 3 . The shock-resistant layer 1 is formed by applying a material (for example, paper, non-woven fabric, woven fabric, resin base material, rubber base material, etc.) for forming the impact-resistant layer 1 to the resin film layer 2 via the adhesive layer 5. It can be formed by adhering to the surface. Alternatively, the impact-resistant layer 1 may be heat-sealed directly to the surface of the resin film layer 2 . The order of the step of laminating the barrier layer 3 on the surface of the resin film layer 2 and the step of laminating the impact resistant layer 1 on the surface of the resin film layer 2 is not particularly limited. For example, after the impact-resistant layer 1 is laminated on the surface of the resin film layer 2 , the barrier layer 3 may be formed on the surface of the resin film layer 2 opposite to the impact-resistant layer 1 .

As described above, in order from the outside, impact resistant layer 1/optionally provided adhesive layer 5/resin film layer 2/optionally provided adhesive layer 6/barrier layer 3/optionally A laminate including the provided adhesive layer 7 / heat-fusible resin layer 4 is formed. In addition, it may be subjected to heat treatment. Moreover, as described above, a colored layer may be provided between the resin film layer 2 and the barrier layer 3 .

4. Use of Power Storage Device Exterior Material The power storage device exterior material of the present disclosure is used in a packaging body for sealingly housing power storage device elements such as a positive electrode, a negative electrode, and an electrolyte. That is, an electricity storage device can be obtained by housing an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte in a package formed by the electricity storage device exterior material of the present disclosure.

Specifically, an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte is placed in the exterior material for an electricity storage device of the present disclosure in a state in which the metal terminals connected to the positive electrode and the negative electrode protrude outward. An electricity storage device using the exterior material for an electricity storage device is provided by covering an electricity storage device element with the exterior material for an electricity storage device and heat-sealing a heat-sealable resin layer to seal. In addition, when housing an electricity storage device element in a package formed by the electricity storage device exterior material of the present disclosure, the heat-fusible resin portion of the electricity storage device exterior material of the present disclosure is on the inside (surface in contact with the electricity storage device element ) to form a package.

As described above, since the power storage device exterior material 10 of the present disclosure includes the shock-resistant layer 1, it is difficult to form the recesses by molding using a mold like the conventional power storage device exterior material. Not suitable. For this reason, the power storage device exterior material 10 of the present disclosure is preferably used without being subjected to molding by a mold. The shape of the power storage device 20 manufactured using the power storage device exterior material 10 of the present disclosure is, for example, a gable top type as shown in FIG. 4, a brick pouch side as shown in FIG. As shown, it preferably has a rectangular parallelepiped shape obtained by combining two lid members 11 and a cylindrical exterior member 10 for an electricity storage device. In the electricity storage device 20 of FIG. 6 , the electricity storage device element is accommodated in a space formed by the cylindrically formed electricity storage device exterior material 10 and two cover members 11 . The power storage device element is sealed by heat-sealing the heat-sealable resin layer 4 of the power storage device exterior material 10 to the periphery.

In manufacturing the electricity storage device 20 of the present disclosure, two or more exterior materials 10 for an electricity storage device of the present disclosure may be used, but it is sufficient to use only one. For example, in each of the power storage devices 20 shown in FIGS. 4 to 6, only one power storage device exterior material 10 of the present disclosure is used. Further, in the manufacture of the electricity storage device 20 of the present disclosure, molding in which the electricity storage device exterior material 10 is stretched by molding using a mold is not necessary.

The power storage device exterior material of the present disclosure can be suitably used for power storage devices such as batteries (including capacitors, capacitors, etc.). Moreover, although the exterior material for an electricity storage device of the present disclosure may be used for either a primary battery or a secondary battery, it is preferably used for a secondary battery. The type of secondary battery to which the power storage device exterior material of the present disclosure is applied is not particularly limited. Cadmium storage batteries, nickel/iron storage batteries, nickel/zinc storage batteries, silver oxide/zinc storage batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors, and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries can be mentioned as suitable targets for application of the power storage device exterior material of the present disclosure. Since the exterior material for an electricity storage device of the present disclosure is excellent in drop impact resistance, for example, an electricity storage device with a large weight of an electricity storage device element, specifically, an electricity storage device with a weight of 500 g or more, preferably 1000 g or more ( It is particularly useful when the upper limit is, for example, 30 kg or less. Moreover, it is particularly useful as an exterior material for an electric storage device, which is likely to be subjected to impact when dropped.

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

<Manufacturing exterior materials for power storage devices>
Example 1
A polyethylene terephthalate (PET) film (thickness: 12 μm) and an oriented nylon (ONy) film (thickness: 15 μm) were prepared as resin film layers. The PET film and the ONy film were adhered via the adhesive layer using a two-liquid type urethane adhesive so that the adhesive layer had a thickness of 3 μm after curing. As a barrier layer, an aluminum foil (JIS H4160: 1994 A8021H-O (thickness: 40 μm) was prepared. Then, after laminating the aluminum foil and the resin film layer (on the ONy side) by a dry lamination method, an aging treatment was performed to produce a laminate of the resin film layer/adhesive layer/barrier layer. Both sides are subjected to chemical conversion treatment.The chemical conversion treatment of the aluminum foil is carried out by applying a treatment liquid consisting of phenolic resin, a chromium fluoride compound, and phosphoric acid so that the coating amount of chromium is 10 mg/m ² (dry mass). Secondly, it was applied to both sides of an aluminum foil by a roll coating method and baked.

Next, an adhesive layer and a heat-fusible resin layer were laminated on the barrier layer of each laminate obtained above. Specifically, maleic anhydride-modified polypropylene (PPa, thickness 40 μm) as an adhesive layer and random polypropylene (PP, thickness 40 μm) as a heat-sealable resin layer are melt co-extruded, respectively. An adhesive layer/heat-fusible resin layer was laminated on the barrier layer to obtain a laminate in which resin film layer/adhesive layer/barrier layer/adhesive layer/heat-fusible resin layer were laminated in this order.

Next, base paper for liquid paper containers (manufactured by Potlatch Co., basis weight: 337 g/m ² ) was prepared as an impact-resistant layer (fibrous base material layer). Next, using a two-liquid urethane adhesive, an impact-resistant layer (fibrous base material layer) is formed on the surface of the resin film layer of the laminate so that the adhesive layer has a thickness of 3 μm after curing. An exterior material for an electric storage device in which an impact-resistant layer (fibrous base material layer)/resin film layer/adhesive layer/barrier layer/adhesive layer/heat-fusible resin layer is laminated in order by pasting (size is 300 mm × 150 mm) was obtained.

Next, the obtained exterior material for an electricity storage device, two polypropylene plates (width 100 mm, length 40 mm, thickness 5 mm) as a lid material, and a metal plate made of aluminum as a simulated electricity storage device element (size is width 100 mm, length 140 mm, thickness 40 mm, weight 1.5 kg) was prepared. As shown in FIG. 6, the space formed by the two cover members and the electrical storage device exterior material formed in a cylindrical shape with the heat-sealable resin layer of the electrical storage device exterior material facing the metal plate. , the heat-sealable resin layer of the exterior material for the electric storage device is heat-sealed to the peripheral edge of the lid so that the metal plate is accommodated (for the four sides with a thickness of 5 mm of each lid) heat-sealing the heat-sealing resin layer of the exterior material for the electricity storage device, respectively), the simulated electricity storage device (that is, the space formed by one exterior material for the electricity storage device and two lids 2, in which a simulated electricity storage device element is accommodated).

Example 2
Impact resistant layer (fibrous base material layer)/resin film layer/adhesive layer/barrier layer/adhesive layer/ An exterior material for an electricity storage device was obtained in which the heat-fusible resin layers were sequentially laminated. In addition, an aluminum metal plate (size: 100 mm wide, 140 mm long, 40 mm thick, weight 1.5 kg) was prepared as a simulated electricity storage device element.

Next, the obtained exterior material for an electricity storage device is of a gable top type on the upper and lower sides (only the upper side is of the gable top type and the lower side is flat in FIG. 4). In this way, the simulated electricity storage device element is wrapped, the heat-sealable resin layer is heat-sealed, and the simulated electricity storage device (that is, in the space formed by one electricity storage device exterior material, the simulated A typical electric storage device element is accommodated).

Example 3
In the same manner as in Example 2, a power storage device exterior material ( The size was 300 mm x 250 mm). In addition, an aluminum metal plate (size: 100 mm wide, 140 mm long, 40 mm thick, weight 1.5 kg) was prepared as a simulated electricity storage device element.

Next, as shown in FIG. 5, the obtained electrical storage device exterior material is shaped into a brick pouch to wrap the simulated electrical storage device element, and the heat-sealable resin layer is heat-sealed to form a simulated electrical storage device element. A typical electricity storage device (that is, a simulated electricity storage device element is accommodated in a space formed by one electricity storage device exterior material) was produced.

Comparative example 1
A simulated power storage device was produced in the same manner as in Example 1, except that the shock-resistant layer (fibrous base material layer) was not provided in the power storage device exterior material.

Comparative example 2
A simulated power storage device was produced in the same manner as in Example 2, except that the shock-resistant layer (fibrous base material layer) was not provided on the power storage device exterior material.

Comparative example 3
A simulated power storage device was produced in the same manner as in Example 3, except that the shock-resistant layer (fibrous base material layer) was not provided in the power storage device exterior material.

<Drop test from a height of 30 cm>
The simulated electricity storage devices obtained in Examples and Comparative Examples were each dropped from a height of 30 cm, and the appearance and state of the aluminum alloy foil were visually observed and evaluated according to the following criteria. It should be noted that the simulated electric storage device was allowed to fall freely with the back-pasted portion facing up. In addition, the state of the aluminum alloy foil was evaluated by obtaining a cross section of the exterior material for the electricity storage device for the outer damaged portion due to the dropping of the electricity storage device. Specifically, we visually inspected from both the outside and inside to see if there was any damage to the exterior material after it was dropped, and in the areas where damage was visually confirmed, we checked the state of the aluminum alloy foil by cross-sectional observation with a microscope. Table 1 shows the results.
(Appearance of exterior material for power storage device)
A: There is no damage to the exterior material for electrical storage device.
B: The exterior material for the electric storage device has no holes, but is damaged.
C: A hole is vacant in the exterior material for electrical storage devices.
(Appearance of aluminum alloy foil)
A: There is no damage to the aluminum alloy foil.
B: The aluminum alloy foil is damaged, but not broken.
C: The aluminum alloy foil is broken.

In the simulated electricity storage device of Example 1-3, base paper for liquid paper containers was laminated as the outermost layer as a shock-resistant layer (fibrous base material layer), and the drop test evaluation from a height of 30 cm was good. rice field.

As described above, the present disclosure provides inventions in the following aspects.
Section 1. An exterior material for an electricity storage device, comprising a laminate comprising, in order from the outside, at least an impact-resistant layer, a resin film layer, a barrier layer, and a heat-fusible resin layer.
Section 2. Item 2. The exterior material for an electricity storage device according to Item 1, wherein the shock-resistant layer is a fibrous base material layer.
Item 3. Item 3. The power storage device exterior material according to

Item

1 or 2, wherein the shock-resistant layer is formed of at least one of paper and nonwoven fabric.
Section 4. Item 4. The exterior material for an electricity storage device according to any one of items 1 to 3, wherein the impact-resistant layer has a basis weight of 100 g/m ² or more.
Item 5. Item 5. The power storage device exterior material according to any one of Items 1 to 4, wherein the shock-resistant layer constitutes the outermost layer of the laminate.
Item 6. Item 6. The power storage device exterior material according to any one of Items 1 to 5, further comprising an adhesive layer between the impact resistant layer and the resin film layer.
Item 7. Item 7. The exterior material for an electricity storage device according to any one of Items 1 to 6, further comprising an adhesive layer between the resin film layer and the barrier layer.
Item 8. Item 8. The exterior material for an electricity storage device according to any one of Items 1 to 7, further comprising an adhesive layer between the barrier layer and the heat-fusible resin layer.
Item 9. Item 9. The power storage device exterior material according to any one of Items 1 to 8, wherein the barrier layer is made of an aluminum alloy foil.
Item 10. A method for producing an exterior material for an electric storage device, comprising a step of obtaining a laminate including, in order from the outside, at least an impact-resistant layer, a resin film layer, a barrier layer, and a heat-fusible resin layer.
Item 11. An electricity storage device, wherein an electricity storage device element comprising at least a positive electrode, a negative electrode, and an electrolyte is accommodated in a package formed of the electricity storage device exterior material according to any one of Items 1 to 9.
Item 12. Item 12. The electricity storage device according to Item 11, wherein the package has a gable top shape or a brick shape.
Item 13. The electricity storage device element is accommodated in a space formed by the electricity storage device exterior material according to any one of items 1 to 9 formed in a cylindrical shape and two cover members,
Item 12. The electricity storage device according to Item 11, wherein the electricity storage device element is sealed by heat-sealing the heat-fusible resin layer of the exterior material for an electricity storage device to the periphery of the lid member.
Item 14. 14. The electricity storage device according to any one of items 11 to 13, wherein only one sheet of the exterior material for an electricity storage device according to any one of items 1 to 9 is used.

Reference Signs List 1 impact-resistant layer 2 resin film layer 3 barrier layer 4 heat-fusible resin layer 5 adhesive layer 6 adhesive layer 7 adhesive layer 10 exterior material for power storage device 11 lid material 20 power storage device

Claims

An exterior material for a power storage device, which is composed of a laminate including, in order from the outside, at least an impact-resistant layer, a resin film layer, a barrier layer, and a heat-fusible resin layer.
The exterior material for an electricity storage device according to claim 1, wherein the shock-resistant layer is a fibrous base material layer.
The power storage device exterior material according to claim 1 or 2, wherein the shock-resistant layer is made of at least one of paper and non-woven fabric.
The exterior material for an electricity storage device according to claim 1 or 2 , wherein the impact-resistant layer has a basis weight of 100 g/m2 or more.
The power storage device exterior material according to claim 1 or 2, wherein the shock-resistant layer constitutes the outermost layer of the laminate.
The power storage device exterior material according to claim 1 or 2, further comprising an adhesive layer between the shock-resistant layer and the resin film layer.
The power storage device exterior material according to claim 1 or 2, further comprising an adhesive layer between the resin film layer and the barrier layer.
The power storage device exterior material according to claim 1 or 2, further comprising an adhesive layer between the barrier layer and the heat-fusible resin layer.
The exterior material for an electricity storage device according to claim 1 or 2, wherein the barrier layer is made of an aluminum alloy foil.
A method for manufacturing an exterior material for an electric storage device, comprising a step of obtaining a laminate including, in order from the outside, at least an impact-resistant layer, a resin film layer, a barrier layer, and a heat-fusible resin layer.
An electricity storage device, wherein an electricity storage device element comprising at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed by the exterior material for an electricity storage device according to claim 1 or 2.
The power storage device according to claim 11, wherein the package has a gable top or brick shape.
The electricity storage device element is accommodated in a space formed by the electricity storage device exterior material according to claim 1 or 2 formed in a cylindrical shape and two cover members,
12. The electricity storage device according to claim 11, wherein the electricity storage device element is sealed by heat-sealing the heat-fusible resin layer of the exterior material for an electricity storage device to the periphery of the lid member.
The electricity storage device according to claim 11, wherein only one sheet of the exterior material for an electricity storage device according to claim 1 or 2 is used.