JP7225833B2 - Exterior material for power storage device, method for manufacturing exterior material for power storage device, and power storage device - Google Patents

Description

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

Conventionally, various types of power storage devices have been developed. In these electric storage devices, an electric storage device element composed of an electrode, an electrolyte, and the like needs to be sealed with an exterior material or the like. Metal exterior materials are often used as exterior materials for power storage devices.

2. Description of the Related Art In recent years, as electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like have become more sophisticated, power storage devices having various shapes have been desired. In addition, there is a demand for thinning and weight reduction of power storage devices. However, it is difficult to follow the diversification of the shape of electric storage devices with the conventionally widely used metal exterior materials. Moreover, since it is made of metal, there is a limit to reducing the weight of the exterior material.

Therefore, as an exterior material for power storage devices that can be easily processed into various shapes and can realize thinness and weight reduction, a film-like laminate in which a substrate layer / a barrier layer / a heat-fusible resin layer are laminated in order. has been proposed (see Patent Document 1, for example).

In such a film-like exterior material for an electricity storage device, a recess is generally formed by molding, and an electricity storage device element such as an electrode or an electrolytic solution is placed in the space formed by the recess, and heat-sealing is performed. By heat-sealing the resin layers to each other, an electricity storage device in which an electricity storage device element is accommodated inside the exterior material for an electricity storage device can be obtained.

JP 2008-287971 A

When moisture enters the inside of the electricity storage device, the moisture may react with the electrolyte or the like to generate an acidic substance. For example, electrolytes used in lithium-ion storage devices contain fluorine compounds ( _LiPF6 , _LiBF4 , etc.) that act as electrolytes, and when the fluorine compounds react with water, hydrogen fluoride is generated. It is known.

A barrier layer of an exterior material for an electricity storage device formed of a film-like laminate is usually made of metal foil or the like, and there is a problem that the barrier layer is easily corroded when acid comes into contact with the barrier layer. As a technique for improving the acid resistance of such an exterior material for an electric storage device, a technique using a barrier layer in which a corrosion-resistant film is formed on the surface by chemical conversion treatment is known.

Conventionally, various methods such as chromate treatment using a chromium compound such as chromium oxide and phosphate treatment using a phosphoric acid compound are known as chemical conversion treatments for forming corrosion-resistant films.

However, as a result of repeated studies by the inventors of the present disclosure, it has been found that the conventional barrier layer provided with the corrosion-resistant film has poor adhesion to the layer adjacent to the side on which the corrosion-resistant film is provided (that is, corrosion resistance). It was found that the adhesion at the interface between the film and the layer in contact therewith) was insufficient. More specifically, when the electrolytic solution adheres to the exterior material for an electric storage device, high adhesion between the corrosion-resistant film and the layer in contact with the film may not be maintained.

Under such circumstances, the main purpose of the present disclosure is to provide an exterior material for an electric storage device in which high adhesion of a barrier layer having a corrosion-resistant film is maintained even when an electrolytic solution adheres. . Another object of the present disclosure is 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.

The inventors of the present disclosure conducted extensive studies to solve the above problems. As a result, it is composed of a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order, and the substrate layer is composed of a single-layer polyester film, At least one surface of the barrier layer is provided with a corrosion-resistant film, and when the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, it is derived from CePO ₄ ⁻ The exterior material for an electricity storage device, in _which the ratio P _PO3 /P CePO4 of the peak intensity P _PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 is in the range of 80 or more and 120 or less, is high even when the electrolyte adheres. It was found that the adhesion was maintained. The present disclosure is an invention completed by further studies based on these findings.

That is, the present disclosure provides inventions in the following aspects.
Consists of a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order,
The base material layer is composed of a single-layer polyester film,
At least one surface of the barrier layer is provided with a corrosion-resistant coating,
When the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the ratio of the peak intensity P PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO ₄ ⁻ is _{P PO3 /} An exterior material for an electricity storage device, wherein P _CePO4 is in the range of 80 or more and 120 or less.

ADVANTAGE OF THE INVENTION According to this indication, the exterior material for electrical storage devices with which the high adhesiveness of the barrier layer provided with the corrosion-resistant film|membrane is maintained even when electrolyte solution adheres can be provided. 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; 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;

The exterior material for an electricity storage device of the present disclosure is composed of a laminate including at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order, and the substrate layer is a single layer of polyester. It is composed of a film, and a corrosion-resistant coating is provided on at least one surface of the barrier layer, and the corrosion-resistant coating is analyzed using time-of-flight secondary ion mass spectrometry. Secondly, the ratio P _PO3 /P _CePO4 of the peak intensity P _PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO ₄ − is in the range of 80 or more and 120 ^or less.

Hereinafter, the power storage device exterior material of the present disclosure, the method for manufacturing the power storage device exterior material, and the power storage device using the power storage device exterior material will be described in detail with reference to FIGS. 1 to 4 .

In this specification, 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.

1. Laminated structure of exterior material for power storage device The exterior material for power storage device of the present disclosure includes at least a base layer 1, a barrier layer 3, and a heat-fusible resin layer 4, as shown in FIGS. 1 to 4, for example. It is composed of a laminated body having in order. In the power storage device exterior material of the present disclosure, the base material layer 1 is the outermost layer, and the heat-fusible resin layer 4 is the innermost layer. That is, when the electricity storage device is assembled, the heat-sealable resin layers 4 positioned at the periphery of the electricity storage device element are heat-sealed to seal the electricity storage device element, thereby sealing the electricity storage device element.

At least one surface of the barrier layer 3 is provided with a corrosion-resistant film. The corrosion resistant coating contains cerium. FIGS. 1 to 4 show schematic diagrams in the case where the power storage device exterior material of the present disclosure includes a corrosion-resistant film 3a on the surface of the barrier layer 3 on the heat-fusible resin layer 4 side. 2 to 4 show schematic diagrams in the case where the exterior material for an electricity storage device of the present disclosure includes corrosion-resistant coatings 3a and 3b on both sides of the barrier layer 3, respectively. As will be described later, in the power storage device exterior material of the present disclosure, only the surface of the barrier layer 3 on the heat-fusible resin layer 4 side may be provided with the corrosion-resistant film 3a. Only the surface of the substrate layer 1 side of the barrier layer 3 may be provided with the corrosion-resistant film 3b, or both surfaces of the barrier layer 3 may be provided with the corrosion-resistant films 3a and 3b, respectively.

As shown in FIGS. 3 and 4, the exterior material for an electricity storage device of the present disclosure has an adhesive layer between the base material layer 1 and the barrier layer 3 for the purpose of increasing the adhesion between them, if necessary. 2 may be provided. Further, as shown in FIGS. 3 and 4, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-fusible resin layer 4, if necessary, for the purpose of enhancing the adhesiveness therebetween. good. In addition, as shown in FIG. 4 , the exterior material for an electricity storage device of the present disclosure, for the purpose of improving design, electrolytic solution resistance, scratch resistance, moldability, etc., may include the base layer 1 A surface coating layer 6 may be provided on the side opposite to the barrier layer 3 as required.

The thickness of the laminate constituting the power storage device exterior material 10 is not particularly limited, but the upper limit is preferably about 180 μm or less, about 155 μm or less, or about 120 μm or less from the viewpoint of cost reduction, energy density improvement, etc. The lower limit is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, about 100 μm or more from the viewpoint of maintaining the function of the electricity storage device exterior material to protect the electricity storage device element, Preferred ranges are, for example, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 180 μm, about 60 to 155 μm, 100 to 155 μm. about 60 to 120 μm, and among these, about 100 to 155 μm is particularly preferable.

In the power storage device exterior material 10 of the present disclosure, when considering the balance of the layered structure of the power storage device exterior material 10, particularly preferable specific layered structures include the following layered structures 1 and 2.
Laminate structure 1: base layer 1 (thickness: 22 to 28 μm) composed of a single-layer polyethylene terephthalate film/adhesive layer 2 (thickness: 2 to 5 μm)/corrosion-resistant coatings 3a and 3b described later on both sides Barrier layer 3 (thickness: 35 to 45 μm) made of aluminum alloy foil/Adhesive layer 5 (thickness: 12 to 18 μm) made of acid-modified polypropylene/Heat-fusible resin layer made of polypropylene 4 (thickness 25 to 35 μm) laminated in this order.
Laminate structure 2: base layer 1 (thickness: 22 to 28 μm) composed of a single-layer polyethylene terephthalate film/adhesive layer 2 (thickness: 2 to 5 μm)/corrosion-resistant films 3a and 3b described later on both sides Barrier layer 3 (thickness: 35 to 45 μm) made of aluminum alloy foil/Adhesive layer 5 (thickness: 22 to 28 μm) made of acid-modified polypropylene/Heat-fusible resin layer made of polypropylene 4 (thickness 50 to 60 μm) laminated in this order.

In the exterior material for an electric storage device, the barrier layer 3, which will be described later, can usually be distinguished between the vertical direction (MD) and the horizontal direction (TD) in the manufacturing process. For example, when the barrier layer 3 is made of an aluminum alloy foil, linear streaks called rolling marks are formed on the surface of the aluminum alloy foil in the rolling direction (RD) of the aluminum alloy foil. ing. Since the rolling marks extend along the rolling direction, the rolling direction of the aluminum alloy foil can be grasped by observing the surface of the aluminum alloy foil. In the manufacturing process of the laminate, the MD of the laminate usually matches the RD of the aluminum alloy foil. By specifying the MD of the laminate can be specified. Moreover, since the TD of the laminate is perpendicular to the MD of the laminate, the TD of the laminate can also be specified.

2. Each layer forming the exterior material for the electricity storage device [base layer 1]
In the present disclosure, the base material layer 1 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 base material layer 1 is located on the outer layer side of the exterior material 10 for electrical storage devices.

In the present disclosure, the substrate layer 1 is composed of a single-layer polyester film. More specifically, in the power storage device exterior material 10 of the present disclosure, only one layer of polyester film exists outside the barrier layer 3 , and the polyester film constitutes the base layer 1 .

The polyester 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.

Specific examples of the polyester constituting the polyester film 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.

Preferably, the polyester film is a polyethylene terephthalate film. The main resin (for example, 80% by mass or more, further 90% by mass or more) constituting the polyethylene terephthalate film is polyethylene terephthalate, and may also contain, for example, polybutylene terephthalate.

Additives such as a lubricant, a flame retardant, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent are present on at least one of the surface and the interior of the polyester film that constitutes the base material layer 1. may be Only one type of additive may be used, or two or more types may be mixed and used.

In the present disclosure, it is preferable that a lubricant exists on the surface of the base material layer 1 from the viewpoint of improving the moldability of the exterior material for an electricity storage device. The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of amide lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide and the like. Further, specific examples of methylolamide include methylol stearamide. Specific examples of saturated fatty acid bisamides include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearin. acid amide, hexamethylenebisbehenamide, hexamethylenehydroxystearic acid amide, N,N'-distearyladipic acid amide, N,N'-distearylsebacic acid amide and the like. Specific examples of unsaturated fatty acid bisamides include ethylenebisoleic acid amide, ethylenebiserucic acid amide, hexamethylenebisoleic acid amide, N,N'-dioleyladipic acid amide, and N,N'-dioleylsebacic acid amide. etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate. Further, specific examples of the aromatic bisamide include m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, N,N'-distearyl isophthalic acid amide and the like. Lubricants may be used singly or in combination of two or more.

When a lubricant exists on the surface of the base material layer 1, its amount is not particularly limited, but is preferably about 3 mg/m ² or more, more preferably about 4 to 15 mg/m ² , and still more preferably 5 to 14 mg. / m ² degree.

The lubricant present on the surface of the substrate layer 1 may be obtained by exuding the lubricant contained in the resin constituting the substrate layer 1, or by coating the surface of the substrate layer 1 with the lubricant. may

The thickness of the base material layer 1 is not particularly limited as long as it functions as a base material. Among these, the thickness of the substrate layer 1 is particularly preferably in the range of 22 to 28 μm.

The tensile breaking strength in at least one direction (perpendicular to the thickness direction) of the polyester film constituting the substrate layer 1 is preferably about 50 to 90 N/15 mm, more preferably about 60 to 80 N/15 mm. More specifically, the tensile strength at break in the MD direction of the polyester film is preferably about 50 to 90 N/15 mm, more preferably about 60 to 80 N/15 mm. Further, the tensile breaking strength of the polyester film in the TD direction is preferably about 60 to 80 N/15 mm, more preferably about 60 to 75 N/15 mm. The tensile strength at break of the polyester film constituting the base material layer 1 is a value measured by the following method.

<Tensile breaking strength of polyester film>
The tensile breaking strength in the machine direction (MD) and transverse direction (TD) of the polyester film is measured using a tensile tester (eg, AG-Xplus (trade name) manufactured by Shimadzu Corporation). The measurement conditions are a rectangular sample with a width of 15 mm, a distance between gauge lines of 50 mm, a tensile speed of 50 mm/min, and a test environment of 23°C.

From the viewpoint of improving the moldability of the exterior material for an electricity storage device of the present disclosure, the tensile breaking strength of the polyester film preferably has a small difference between the longitudinal direction (MD) and the transverse direction (TD), and the difference is 0 to 10 N. /15 mm.

[Adhesive layer 2]
In the power storage device exterior material of the present disclosure, the adhesive layer 2 is a layer provided between the base layer 1 and the barrier layer 3 as necessary for the purpose of enhancing the adhesiveness between them.

The adhesive layer 2 is made of an adhesive capable of bonding the base material layer 1 and the barrier layer 3 together. The adhesive used to form the adhesive layer 2 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 2 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 main agent containing a polyol compound and a curing agent containing an isocyanate compound. Two-component curing type polyurethane adhesives using polyols such as polyester polyols, polyether polyols, and acrylic polyols as main agents and aromatic or aliphatic polyisocyanates as curing agents are preferred. Moreover, 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. Since the adhesive layer 2 is formed of a polyurethane adhesive, the exterior material for an electric storage device is imparted with excellent electrolyte resistance, and even if the electrolyte adheres to the side surface, the base layer 1 is suppressed from being peeled off. .

Further, the adhesive layer 2 may contain other components as long as they do not impede adhesion, and may contain colorants, thermoplastic elastomers, tackifiers, fillers, and the like. Since the adhesive layer 2 contains a coloring agent, the exterior material for an electric storage device 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 2 . Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments. Examples of 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 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 2 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 2 is not particularly limited as long as the substrate layer 1 and the barrier layer 3 can be adhered. , about 5 μm or less. Preferred ranges include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm, and among these, about 2 to 5 μm is particularly preferable.

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

The colored layer can be formed, for example, by applying ink containing a coloring agent to the surface of the substrate layer 1, the adhesive layer 2, or the barrier layer 3. 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.

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

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

As the barrier layer 3, for example, a metal foil, a deposited film, a resin layer, or the like having barrier properties can be used. 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 that constitutes the barrier layer 3 include aluminum alloys, stainless steels, titanium steels, and steel plates. When used as a metal foil, at least one of an aluminum alloy foil and a stainless steel foil is included. is preferred.

The aluminum alloy foil is more preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, from the viewpoint of improving the formability of the exterior material for an electricity storage device, and from the viewpoint of further improving the formability. Therefore, it is preferably an aluminum alloy foil containing iron. 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 0.1% by mass or more, it is possible to obtain an exterior material for an electricity storage device having superior moldability. 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, JIS H4160: 1994 A8021H-O, JIS H4160: 1994 A8079H-O, JIS H4000: 2014 A8021P-O, or an aluminum alloy having a composition specified by 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.

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 with excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

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

The thickness of the barrier layer 3, in the case of a metal foil, is sufficient to exhibit at least the function of a barrier layer that prevents permeation of moisture, and is, for example, about 9 to 200 μm. Regarding the thickness of the barrier layer 3, for example, the upper limit is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. 10 μm or more, more preferably about 20 μm or more, more preferably about 25 μm or more. About 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 3 is made of an aluminum alloy foil, the above range is particularly preferable, and about 35 to 45 μm is particularly preferable. In particular, when the barrier layer 3 is made of stainless steel foil, the upper limit of the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, and even more preferably about 40 μm or less. It is more preferably about 30 μm or less, particularly preferably about 25 μm or less, and the lower limit is preferably about 10 μm or more, more preferably about 15 μm or more. about 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[Corrosion-resistant coatings 3a and 3b]
In the power storage device exterior material of the present disclosure, a corrosion-resistant film is provided on at least one surface of the barrier layer 3 . In the power storage device exterior material of the present disclosure, the corrosion-resistant film 3a may be provided only on the surface of the barrier layer 3 on the heat-fusible resin layer 4 side, or the barrier layer 3 on the base layer 1 side. Only the surface of the barrier layer 3 may be provided with the corrosion-resistant film 3b, or both surfaces of the barrier layer 3 may be provided with the corrosion-resistant films 3a and 3b, respectively.

In addition, in the exterior material for an electricity ^storage device of the present disclosure, when the corrosion-resistant film is analyzed using time ^- of-flight secondary ion mass spectrometry, the peak intensity P _CePO4 derived from CePO _{4 -} The ratio P _PO3 /P _CePO4 of peak intensities P _PO3 derived from is in the range of 80-120. The peak intensity ratio P _PO3 /P _CePO4 should be within the above range, but both of the corrosion resistant coatings 3a and 3b should have the peak intensity ratio P _PO3 /P _CePO4 within the above range. is preferred. In particular, the corrosion-resistant film 3a located on the heat-fusible resin layer side of the barrier layer and the layers adjacent thereto (for example, the adhesive layer 5 provided as necessary, the heat-fusible resin layer 4, etc.) ) means that the adhesion is likely to decrease due to the permeation of the electrolytic solution, so in the power storage device exterior material of the present disclosure, the corrosion-resistant film 3a and the peak intensity ratio P _PO3 /P _CePO4 of the corrosion resistant coating 3a is preferably within the above range. These points are the same for each peak intensity ratio shown below.

In the present disclosure, the ratio P _PO3 /P _CePO4 of the peak intensity P _PO3 derived from _{PO 3 −} ^to the peak intensity P _CePO4 derived from CePO 4 − should be in the range of 80 to 120 ^. From the viewpoint of further enhancing the adhesion of the barrier layer provided, the lower limit of the ratio P _PO3 /P _CePO4 is preferably about 85 or more, more preferably about 92 or more, and the upper limit is preferably about 110 or less. More preferably about 105 or less, more preferably about 98 or less. The range of the peak intensity ratio P _PO3 /P _CePO4 is preferably about 80 to 110, about 80 to 105, about 80 to 98, about 85 to 120, about 85 to 110, about 85 to 105, 85 about 98, about 92 to 120, about 92 to 110, about 92 to 105, and about 92 to 98.

Specifically, the method of analyzing the corrosion-resistant coatings 3a and 3b using time-of-flight secondary ion mass spectrometry is performed under the following measurement conditions using a time-of-flight secondary ion mass spectrometer. be able to.

(Measurement condition)
Primary ions: Double charged ions of bismuth clusters (Bi ₃ ⁺⁺ )
Primary ion acceleration voltage: 30 kV
Mass range (m/z): 0-1500
Measurement range: 100 μm×100 μm
Number of scans: 16 scans/cycle
Number of pixels (one side): 256 pixels
Etching ion: Ar gas cluster ion beam (Ar-GCIB)
Etching ion acceleration voltage: 5.0 kV

In addition, it can be confirmed using X-ray photoelectron spectroscopy that the corrosion-resistant film contains cerium. Specifically, first, the layers (adhesive layer, heat-fusible resin layer, adhesive layer, etc.) laminated on the barrier layer in the power storage device exterior material are physically peeled off. Next, the barrier layer is placed in an electric furnace, and organic components present on the surface of the barrier layer are removed at about 300° C. for about 30 minutes. The inclusion of cerium is then confirmed using X-ray photoelectron spectroscopy of the surface of the barrier layer.

The corrosion-resistant coatings 3a and 3b can be formed by subjecting the surface of the barrier layer 3 to chemical conversion treatment using a treatment liquid containing a cerium compound such as cerium oxide.

As a chemical conversion treatment using a treatment liquid containing a cerium compound, for example, phosphoric acid and/or a salt thereof in which a cerium compound such as cerium oxide is dispersed is applied to the surface of the barrier layer 3, followed by baking. A method of forming a corrosion-resistant film on the surface of the barrier layer 3 by carrying out.

The peak intensity ratio P _PO3 /P _CePO4 of the corrosion-resistant films 3a and 3b depends on manufacturing conditions such as the composition of the treatment liquid for forming the corrosion-resistant films 3a and 3b and the temperature and time of the baking treatment after treatment. can be adjusted.

The ratio of the cerium compound and the phosphoric acid and/or its salt in the treatment liquid containing the cerium compound is not particularly limited, but from the viewpoint of setting the peak intensity ratio P _PO3 /P _CePO4 within the above range, the cerium The ratio of phosphoric acid and/or a salt thereof to 100 parts by mass of the compound is preferably about 12 to 28 parts by mass, more preferably about 15 to 25 parts by mass. As phosphoric acid and its salt, for example, condensed phosphoric acid and its salt can also be used.

The treatment liquid containing the cerium compound may further contain an anionic polymer and a cross-linking agent for cross-linking the anionic polymer. Examples of anionic polymers include poly(meth)acrylic acid or its salts, copolymers containing (meth)acrylic acid or its salts as main components, and the like. Examples of cross-linking agents include compounds having functional groups such as isocyanate groups, glycidyl groups, carboxyl groups, and oxazoline groups, and silane coupling agents. Each of the anionic polymer and the cross-linking agent may be of one kind, or two or more kinds thereof.

Moreover, from the viewpoint of enhancing the adhesion of the barrier layer having the corrosion-resistant film while exhibiting excellent corrosion resistance, the treatment liquid containing the cerium compound preferably contains an aminated phenol polymer. In the treatment liquid containing a cerium compound, the content of the aminated phenol polymer is preferably about 100 to 400 parts by mass, more preferably about 200 to 300 parts by mass, per 100 parts by mass of the cerium compound. Moreover, the weight average molecular weight of the aminated phenol polymer is preferably about 5,000 to 20,000. The weight average molecular weight of the aminated phenol polymer is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard sample.

The solvent for the treatment liquid containing the cerium compound is not particularly limited as long as it disperses the components contained in the treatment liquid and is then evaporated by heating, but water is preferred. The solid content concentration of the treatment liquid containing the cerium compound is, for example, about 8 to 30% by mass.

The solid content concentration of the cerium compound contained in the treatment liquid for forming the corrosion-resistant film is not particularly limited, but the peak intensity ratio P _PO3 /P _CePO4 is set within the predetermined range to achieve excellent corrosion resistance. From the viewpoint of enhancing the adhesion of the barrier layer with the corrosion-resistant film while exhibiting the More preferably, it is about 9.1 to 10.0 parts by mass.

Although the thickness of the corrosion-resistant coating is not particularly limited, it is preferably about 1 nm to 10 μm, more preferably about 1 nm to 10 μm, from the viewpoint of enhancing the adhesion of the barrier layer provided with the corrosion-resistant coating while exhibiting excellent corrosion resistance. It is preferably about 1 to 100 nm, more preferably about 1 to 50 nm. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope, or a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron beam energy loss spectroscopy.

From the same point of view, the amount of the corrosion-resistant film ^per square meter of the surface of the barrier layer 3 is preferably about 2-100 mg, more preferably about 2-70 mg, and even more preferably about 2-40 mg.

Methods for applying the treatment liquid to the surface of the barrier layer 3 include, for example, a bar coating method, a roll coating method, a gravure coating method, and an immersion method.

By setting the peak intensity ratio P _PO3 /P _CePO4 within the above-mentioned predetermined range, the treatment liquid is used to improve the adhesion of the barrier layer having the corrosion-resistant film while exhibiting excellent corrosion resistance. The heating temperature for baking to form a corrosion-resistant film is preferably about 170 to 250°C, more preferably about 180 to 220°C, and even more preferably about 190 to 220°C. From the same point of view, the baking time is preferably about 2 to 10 seconds, more preferably about 3 to 6 seconds.

From the viewpoint of performing the chemical conversion treatment on the surface of the barrier layer more efficiently, before providing the corrosion-resistant film on the surface of the barrier layer 3, an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid It is preferable to perform the degreasing treatment by a known treatment method such as an activation method.

[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 . In the case where 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.

Preferred acid-modified polyolefins include carboxylic acid- or anhydride-modified polyolefins, carboxylic acid- or anhydride-modified polypropylenes, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

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.

Moreover, the heat-fusible resin layer 4 may contain a lubricant or the like as necessary. When the heat-fusible resin layer 4 contains a lubricant, it is possible to improve the moldability of the power storage device exterior material. The lubricant is not particularly limited, and known lubricants can be used. Lubricants may be used singly or in combination of two or more.

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

When a lubricant exists on the surface of the heat-sealable resin layer 4, the amount of the lubricant is not particularly limited, but from the viewpoint of improving the moldability of the exterior material for an electricity storage device, the amount is preferably about 10 to 50 mg/m ² . , and more preferably about 15 to 40 mg/m ² .

The lubricant present on the surface of the heat-fusible resin layer 4 may be obtained by exuding the lubricant contained in the resin constituting the heat-fusible resin layer 4 . The surface may be coated with a lubricant.

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. About 85 μm or less, more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described later is 10 μm or more, the thickness of the heat-fusible resin layer 4 is preferably about 85 μm or less, about 25 to 35 μm, or about 50 to 60 μm. . More specifically, considering the balance of the laminated structure of the power storage device exterior material 10, when the thickness of the adhesive layer 5 is set to about 12 to 18 μm, the thickness of the heat-fusible resin layer 4 is preferably about 25 to 35 μm, and when the thickness of the adhesive layer 5 is set to about 22 to 28 μm, the thickness of the heat-fusible resin layer 4 is preferably set to about 50 to 60 μm. . For example, when the thickness of the adhesive layer 5 described later is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-fusible resin layer 4 is preferably about 20 μm or more, more preferably about 20 μm or more. About 35 to 85 μm can be mentioned.

[Adhesion layer 5]
In the power storage device exterior material of the present disclosure, the adhesive layer 5 is provided between the barrier layer 3 (or the corrosion-resistant film 3a) and the heat-fusible resin layer 4 as necessary in order to firmly bond them. layer to be provided.

The adhesive layer 5 is made of a resin capable of bonding the barrier layer 3 (or the corrosion-resistant film 3a) and the heat-fusible resin layer 4 together. As the resin used for forming the adhesive layer 5, for example, the same adhesives as those exemplified for the adhesive layer 2 can be used. The resin used to form the adhesive layer 5 preferably contains a polyolefin skeleton, and includes the polyolefins and acid-modified polyolefins exemplified for the heat-fusible resin layer 4 described above. Whether the resin constituting the adhesive layer 5 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, when the resin forming the adhesive layer 5 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 . 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.

From the viewpoint of firmly bonding the barrier layer 3 (or the corrosion-resistant film 3a) and the heat-fusible resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. Particularly preferred acid-modified polyolefins are 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.

Furthermore, from the viewpoint of making the power storage device exterior material excellent in shape stability after molding while reducing the thickness of the power storage device exterior material, the adhesive layer 5 is made of a resin composition containing an acid-modified polyolefin and a curing agent. is more preferably a cured product of Preferred examples of the acid-modified polyolefin include those mentioned above.

Further, the adhesive layer 5 is a cured product of a resin composition containing 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 5 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 amide ester resin is preferable. Amide ester resins are generally produced by the reaction of carboxyl groups and oxazoline groups. More preferably, the adhesive layer 5 is a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. In the case where the adhesive layer 5 contains an isocyanate group-containing compound, an oxazoline group-containing compound, or an unreacted product of a curing agent such as an epoxy resin, 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 enhancing the adhesion between the barrier layer 3 (or the corrosion-resistant film 3a) and the adhesive layer 5, the adhesive layer 5 contains oxygen atoms, heterocycles, C═N bonds, and C—O—C bonds. It is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of. 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, examples of curing agents having a C—O—C bond include curing agents having an oxazoline group, curing agents having an epoxy group, and polyurethanes. The adhesive layer 5 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 (or the corrosion-resistant coating 3a) and the adhesive layer 5, 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, burettes, isocyanurates and the like are included.

The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, more preferably 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. A range is more preferred. Thereby, the adhesion between the barrier layer 3 (or the corrosion-resistant film 3a) and the adhesive layer 5 can be effectively enhanced.

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 5 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 5. is more preferable. Thereby, the adhesion between the barrier layer 3 (or the corrosion-resistant film 3a) and the adhesive layer 5 can be effectively enhanced.

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, novolak glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, and the like. An epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more types.

The proportion of the epoxy resin in the adhesive layer 5 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 5. is more preferred. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively improved.

Polyurethane is not particularly limited, and known polyurethanes can be used. The adhesive layer 5 may be, for example, a cured product of two-component curing type polyurethane.

The proportion of polyurethane in the adhesive layer 5 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 5. more preferred. As a result, the adhesion between the barrier layer 3 (or the corrosion-resistant film 3a) and the adhesive layer 5 can be effectively enhanced in an atmosphere in which a component that induces corrosion of the barrier layer, such as an electrolytic solution, is present.

In addition, when the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin. , the acid-modified polyolefin functions as 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 upper limit of the thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 5 μm or less, and the lower limit is preferably about 0.1 μm or more. , about 0.5 μm or more, and the thickness range 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, 0 .1 to 5 μm, 0.5 to 50 μm, 0.5 to 40 μm, 0.5 to 30 μm, 0.5 to 20 μm, and 0.5 to 5 μm. More specifically, in the case of the adhesive exemplified for the adhesive layer 2 or the cured product of acid-modified polyolefin and 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, about 10 to 40 μm, about 12 to 18 μm, and about 22 to 28 μm. As described above, considering the balance of the laminated structure of the power storage device exterior material 10, when the thickness of the adhesive layer 5 is set to about 12 to 18 μm, the thickness of the heat-fusible resin layer 4 is 25 μm. The thickness of the adhesive layer 5 is preferably set to about 22 to 28 μm, and the thickness of the heat-fusible resin layer 4 is preferably set to about 50 to 60 μm. When the adhesive layer 5 is the adhesive exemplified for the adhesive layer 2 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 5 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 5 can be formed by extrusion molding, for example.

[Surface coating layer 6]
For the purpose of at least one of improving design, electrolyte resistance, scratch resistance, moldability, etc., the exterior material for an electricity storage device of the present disclosure is provided on the base layer 1 (base layer 1 (the side opposite to the barrier layer 3) may be provided with a surface coating layer 6. The surface coating layer 6 is a layer positioned on the outermost layer side of the exterior material for an electricity storage device when an electricity storage device is assembled using the exterior material for an electricity storage device.

The surface coating layer 6 can be formed of resin such as polyvinylidene chloride, polyester, polyurethane, acrylic resin, and epoxy resin, for example.

When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-component curable type or a two-component curable type, preferably the two-component curable type. Examples of the two-liquid curing resin include two-liquid curing polyurethane, two-liquid curing polyester, and two-liquid curing epoxy resin. Among these, two-liquid curable polyurethane is preferred.

Examples of two-liquid curable polyurethanes include polyurethanes containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferable examples include two-component curing type polyurethanes using polyols such as polyester polyols, polyether polyols, and acrylic polyols as main agents and aromatic or aliphatic polyisocyanates as curing agents. Moreover, 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. Since the surface coating layer 6 is made of polyurethane, the exterior material for an electric storage device is imparted with excellent electrolyte resistance.

At least one of the surface and the inside of the surface coating layer 6 may be coated with the above-described lubricant or anti-rust agent as necessary depending on the functionality to be provided on the surface coating layer 6 and its surface. Additives such as blocking agents, matting agents, flame retardants, antioxidants, tackifiers and antistatic agents may be included. Examples of the additive include fine particles having an average particle size of about 0.5 nm to 5 μm. The average particle size of the additive is the median size measured with a laser diffraction/scattering particle size distribution analyzer.

Additives may be either inorganic or organic. Also, the shape of the additive is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, scale-like, and the like.

Specific examples of additives include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, and antimony oxide. , titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotube, high melting point nylon, acrylate resin, Crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, and the like. Additives may be used singly or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferred from the viewpoint of dispersion stability and cost. In addition, the additive may be subjected to various surface treatments such as insulation treatment and high-dispersion treatment.

A method for forming the surface coating layer 6 is not particularly limited, and an example thereof includes a method of applying a resin for forming the surface coating layer 6 . When adding additives to the surface coating layer 6, a resin mixed with the additives may be applied.

The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above functions as the surface coating layer 6, and is, for example, approximately 0.5 to 10 μm, preferably approximately 1 to 5 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 disclosure is obtained. A method including a step of laminating the layer 1, the barrier layer 3, and the heat-fusible resin layer 4 in this order may be mentioned. That is, in the method for producing an exterior material for an electricity storage device of the present disclosure, at least the base material layer 1, the barrier layer 3, and the heat-fusible resin layer 4 are laminated in this order to obtain a laminate. The substrate layer 1 is composed of a single-layer polyester film, and a corrosion-resistant coating is provided on at least one surface of the barrier layer 3. The corrosion-resistant coating includes: When analyzed using time-of-flight secondary ion mass spectrometry, the ratio P _PO3 /P _CePO4 of the peak intensity P _PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO ₄ ⁻ is 80 or more and 120. It is characterized by being within the following range.

An example of the method for manufacturing the exterior material for an electricity storage device of the present disclosure is as follows. First, a laminate (hereinafter sometimes referred to as "laminate A") in which a substrate layer 1, an adhesive layer 2, and a barrier layer 3 having a corrosion-resistant coating on at least one surface are laminated in this order is prepared. Form. Specifically, the laminate A is formed by applying an adhesive used for forming the adhesive layer 2 on the substrate layer 1 or on the barrier layer 3 whose surface is chemically treated by a gravure coating method, a roll coating method, or the like. After coating and drying by the coating method of (1), the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured by a dry lamination method.

Next, on the barrier layer 3 of the laminate A, the heat-fusible resin layer 4 is laminated. 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 5 is provided between the barrier layer 3 and the heat-fusible resin layer 4, for example, (1) the adhesive layer 5 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 5 is laminated on the barrier layer 3 of the laminate A, and laminating this with a heat-fusible resin layer 4 by a thermal lamination method Lamination method (3) While pouring the melted adhesive layer 5 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 5 is interposed. (4) coating the barrier layer 3 of the laminate A with an adhesive for forming the adhesive layer 5 in solution, A drying method, a baking method, or the like is used to laminate the adhesive layer 5 , and a heat-fusible resin layer 4 that has been formed into a sheet in advance is laminated on the adhesive layer 5 .

When providing the surface coating layer 6 , the surface coating layer 6 is laminated on the surface of the substrate layer 1 opposite to the barrier layer 3 . The surface coating layer 6 can be formed, for example, by coating the surface of the substrate layer 1 with the above-described resin for forming the surface coating layer 6 . The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the substrate layer 1 , the barrier layer 3 may be formed on the surface of the substrate layer 1 opposite to the surface coating layer 6 .

Surface coating layer 6/base layer 1/adhesive layer 2 optionally provided/barrier layer 3 provided with a corrosion-resistant film on at least one side surface/required as described above In order to strengthen the adhesiveness of the adhesive layer 2, which is provided as necessary, a laminate is formed that includes the adhesive layer 5 and the heat-fusible resin layer 4 in this order. It may be subjected to heat treatment.

In the exterior material for an electricity storage device, each layer constituting the laminate may be subjected to surface activation treatment such as corona treatment, blasting treatment, oxidation treatment, and ozone treatment to improve processability as necessary. . For example, by subjecting the surface of the substrate layer 1 opposite to the barrier layer 3 to corona treatment, the printability of the ink onto the surface of the substrate layer 1 can be improved.

4. Use of Power Storage Device Exterior Material The power storage device exterior material of the present disclosure is used in a package for sealingly containing 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. In addition, in the power storage device exterior material of the present disclosure, the peak strength and the like can be analyzed by cutting the power storage device exterior material from the power storage device. When cutting the exterior material for an electricity storage device from the electricity storage device, a sample is obtained from a portion where the heat-fusible resin layers are not heat-sealed, such as the top surface and the bottom surface of the electricity storage device, and used for analysis.

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 metal terminals connected to the positive electrode and the negative electrode protrude outward. , covering the periphery of the electricity storage device element so as to form a flange portion (area where the heat-fusible resin layers contact each other), and heat-sealing the heat-fusible resin layers of the flange portion to seal. provides an electricity storage device using an exterior material for an electricity storage device. 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.

The power storage device exterior material of the present disclosure may be used for either a primary battery or a secondary battery, preferably 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. - Examples include 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 application targets of the battery outer packaging material of the present disclosure.

In the power storage device exterior material of the present disclosure, the barrier layer including the corrosion-resistant film can maintain adhesion over a long period of time. Therefore, the exterior material for an electricity storage device of the present disclosure is particularly useful as an exterior material for large-sized electricity storage devices used in vehicles such as hybrid vehicles and electric vehicles.

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

<Manufacturing exterior materials for power storage devices>
Example 1
A biaxially oriented polyethylene terephthalate film (PET film, thickness 25 μm) was prepared as a substrate layer. Next, a barrier layer composed of an aluminum alloy foil (JIS H4160: 1994 A8021H-O, thickness 40 μm) provided with a corrosion-resistant coating (20 nm thickness) is formed by subjecting both surfaces to chemical conversion treatment by the method described below. , was laminated on the surface of the substrate layer by a dry lamination method. Specifically, a two-liquid urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one side of an aluminum alloy foil with a corrosion-resistant film to form an adhesive layer (thickness: 3 μm). bottom. Next, after laminating the adhesive layer on the barrier layer provided with the corrosion-resistant film and the base material layer, aging treatment is performed to obtain anti-corrosion properties on both sides of the biaxially oriented polyethylene terephthalate film/adhesive layer/both sides. Laminates of barrier layers with coatings were prepared.

Next, an adhesive layer (thickness 15 μm) and a heat-fusible resin layer (thickness: 30 μm) were laminated. Next, by aging the obtained laminate, a biaxially stretched polyethylene terephthalate film (base layer 25 μm)/adhesive layer (3 μm)/barrier layer (40 μm) provided with a corrosion-resistant film (20 nm) on both sides )/acid-modified polypropylene (adhesive layer: 15 μm)/random polypropylene (heat-fusible resin layer: 30 μm) were laminated in this order to obtain an exterior material for an electric storage device.

The corrosion-resistant film on the surface of the barrier layer is a treatment liquid containing 100 parts by mass of cerium oxide and 20 parts by mass of an inorganic phosphorus compound (sodium phosphate) (water is included as a solvent, and the solid content is concentration of about 10% by mass) is prepared, the treatment liquid is applied to both sides of the barrier layer (film thickness after drying is 20 nm), and the surface temperature of the barrier layer is about 190° C. for about 3 seconds. It was formed by heating and drying.

Example 2
In Example 1, on the surface of the corrosion-resistant film of the laminate of biaxially oriented polyethylene terephthalate film/adhesive layer/barrier layers provided with corrosion-resistant films on both sides, maleic anhydride-modified polypropylene as an adhesive layer, The procedure was the same as in Example 1, except that an adhesive layer (thickness: 25 μm) and a heat-fusible resin layer (thickness: 55 μm) were laminated by co-extrusion with random polypropylene as the heat-fusible resin layer. Biaxially oriented polyethylene terephthalate film (base layer 25 μm)/adhesive layer (3 μm)/barrier layer (40 μm) provided with corrosion-resistant coating (20 nm) on both sides/acid-modified polypropylene (adhesive layer 25 μm)/random A packaging material for an electricity storage device was obtained in which polypropylene (heat-fusible resin layer: 55 μm) was laminated in this order. The aluminum alloy foil used as the barrier layer was provided with the same corrosion-resistant film as in Example 1.

Comparative example 1
The surface of a biaxially stretched nylon film (25 μm) as a base material layer was subjected to chemical conversion treatment on both sides by the method described later, and an aluminum alloy foil (JIS H4160 : 1994 A8021H-O, thickness 40 μm) was laminated by a dry lamination method. Specifically, a two-liquid urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one side of an aluminum alloy foil with a corrosion-resistant film to form an adhesive layer (thickness: 3 μm). bottom. Next, after laminating an adhesive layer on the barrier layer provided with a corrosion-resistant film and a biaxially stretched nylon film as a base layer, aging treatment is performed to obtain a biaxially stretched nylon film/adhesive layer/ A laminate of barrier layers with corrosion resistant coatings on both sides was prepared.

Next, an adhesive (with a thickness of 3 μm after curing) composed of an amorphous polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound is applied as an adhesive layer to the surface of the corrosion-resistant film of the obtained laminate. and dried. On the adhesive side of the laminate, an unstretched laminated polypropylene film (random polypropylene (4 μm thick)/block polypropylene (22 μm thick)/random polypropylene (4 μm thick) as a first heat-fusible resin layer, A total thickness of 30 μm) was laminated and adhered by passing between two heated rolls. Furthermore, by extruding random polypropylene (thickness 20 μm) as a second heat-fusible resin layer from above, an adhesive layer/heat-fusible resin layer (two layers) is laminated on the barrier layer. rice field. Next, by aging the obtained laminate, biaxially stretched nylon film (25 μm)/adhesive layer (3 μm)/barrier layer (40 μm) provided with corrosion-resistant coatings (thickness 20 nm) on both sides/ An exterior material for an electric storage device was obtained in which an adhesive layer (3 μm)/unstretched laminated polypropylene film (30 μm)/random polypropylene (20 μm) were laminated in this order.

The formation of the corrosion-resistant film on the surface of the barrier layer was carried out as follows. A treatment liquid containing 43 parts by weight of an aminated phenolic polymer, 16 parts by weight of chromium fluoride, and 13 parts by weight of phosphoric acid is added to 100 parts by weight of water, and the treatment liquid is applied to both sides of the barrier layer (after drying). was 20 nm), and the surface temperature of the barrier layer was about 190° C. for about 3 seconds.

Comparative example 2
A biaxially oriented nylon film (25 μm)/ Adhesive layer (3 μm)/barrier layer (40 μm) provided with corrosion-resistant coating (thickness 20 nm) on both sides/adhesive layer (3 μm)/unstretched laminated polypropylene film (30 μm)/random polypropylene (50 μm). An exterior material for an electricity storage device, which was laminated in order, was obtained. As the barrier layer, the aluminum alloy foil provided with the same corrosion-resistant film as in Comparative Example 1 was used.

Comparative Examples 3 and 4
As a substrate layer, a laminated film obtained by laminating polyethylene terephthalate and nylon by co-extrusion and biaxially stretching was prepared. In the laminated film, between the biaxially stretched polyethylene terephthalate film (thickness 5 μm) and the biaxially stretched nylon film (thickness 20 μm), a resin containing a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid derivative component They are adhered by an adhesive layer (adhesive, thickness 1 μm) using a composition. Next, a barrier layer composed of an aluminum alloy foil (JIS H4160: 1994 A8021H-O, thickness 40 μm) provided with a corrosion-resistant coating (20 nm thickness) is formed by subjecting both surfaces to chemical conversion treatment by the method described below. , was laminated on the surface of the biaxially oriented nylon film by a dry lamination method. Specifically, a two-liquid urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one side of an aluminum alloy foil with a corrosion-resistant film to form an adhesive layer (thickness: 3 μm). bottom. Next, after laminating the adhesive layer on the barrier layer provided with the corrosion-resistant film and the biaxially oriented nylon film side of the base layer, aging treatment is performed to obtain a biaxially oriented polyethylene terephthalate film/adhesive. A laminate of /biaxially oriented nylon film/adhesive layer/barrier layer with corrosion-resistant coatings on both sides was prepared.

Next, an adhesive (with a thickness of 3 μm after curing) composed of an amorphous polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound is applied as an adhesive layer to the surface of the corrosion-resistant film of the obtained laminate. and dried. On the adhesive side of the laminate, as a heat-fusible resin layer, an unstretched laminated polypropylene film (random polypropylene (thickness 5 μm) / block polypropylene (thickness 30 μm) / random polypropylene (thickness 5 μm), total thickness 40 μm thick) was laminated, passed between two heated rolls and adhered, thereby laminating an adhesive layer/heat-fusible resin layer on the barrier layer. Next, by curing (aging) the obtained laminate, biaxially stretched polyethylene terephthalate film (5 μm)/adhesive (1 μm)/biaxially stretched nylon film (20 μm)/adhesive layer (3 μm)/both sides A barrier layer (40 μm) provided with a corrosion-resistant coating (thickness: 20 nm)/adhesive layer (3 μm)/unstretched laminated polypropylene film (40 μm) were laminated in this order to obtain an exterior material for an electric storage device.

The corrosion-resistant film on the surface of the barrier layer is formed on the surface of the barrier layer. Exterior materials for power storage devices were obtained in the same manner as in Example 1, except that the weight was about 1.5 times (mass ratio) that in Example.

<Time-of-Flight Secondary Ion Mass Spectrometry>
Analysis of the corrosion-resistant film was performed as follows. First, the barrier layer and the adhesive layer were separated. At this time, the peeling was performed physically without using water, an organic solvent, an aqueous solution of an acid or an alkali, or the like. Since the adhesive layer remained on the surface of the barrier layer after the separation between the barrier layer and the adhesive layer, the remaining adhesive layer was removed by etching with Ar-GCIB. The surface of the barrier layer thus obtained was analyzed for a corrosion-resistant film using time-of-flight secondary ion mass spectrometry. Table 1 shows the peak intensities ^PCePO4 and _PPO3 derived from _CePO4- and _PO3- ^, respectively, and the ratio _PPO3 / _PCePO4 of the peak intensity _PPO3 to the _peak intensity _PCePO4 . In _Comparative Examples 1 and 2, chromium was used in the treatment solution for the chemical conversion treatment, and _cerium was not used ^. indicated by

The details of the measurement apparatus and measurement conditions for time-of-flight secondary ion mass spectrometry are as follows.
Measuring device: Time-of-flight secondary ion mass spectrometer TOF. manufactured by ION-TOF. SIMS5 (measurement conditions)
Primary ions: Double charged ions of bismuth clusters (Bi ₃ ⁺⁺ )
Primary ion acceleration voltage: 30 kV
Mass range (m/z): 0-1500
Measurement range: 100 μm×100 μm
Number of scans: 16 scans/cycle
Number of pixels (one side): 256 pixels
Etching ion: Ar gas cluster ion beam (Ar-GCIB)
Etching ion acceleration voltage: 5.0 kV

<Evaluation of Adhesion>
The adhesion between the barrier layer and the heat-fusible resin layer was evaluated by measuring the peel strength (N/15 mm) when the electrolytic solution adhered to the exterior material for the electrical storage device by the following method. rice field.

First, each of the electrical storage device exterior materials obtained above was cut into a size of 15 mm (TD: transverse direction, lateral direction) and 100 mm (MD: machine direction, longitudinal direction) to obtain test pieces. A test piece was placed in a glass bottle, and lithium hexafluorophosphate (concentration in solution: 1× ¹⁰ mol/m ³ )) was inserted so that the entire test piece was immersed in the electrolytic solution. In this state, the glass bottle was capped and sealed. The sealed vial was placed in an oven set at 85° C. and left for 24 hours. Next, the glass bottle was taken out from the oven, and the test piece was taken out from the glass bottle, washed with water, and the moisture on the surface of the test piece was wiped off with a towel.

Next, the heat-fusible resin layer and the barrier layer of the test piece are separated, and the heat-fusible resin layer side and the barrier layer side of the test piece are subjected to a tensile tester (trade name: AGS-XPlus manufactured by Shimadzu Corporation). The peel strength (N/15 mm) of the test piece was measured by pulling it in the direction of 180° at a speed of 50 mm/min with a distance between gauge lines of 50 mm. The peel strength of the test piece was measured within 10 minutes after wiping off moisture on the surface of the test piece with a towel. The strength when the distance between the gauge lines reached 57 mm was taken as the peel strength of the test piece.

On the other hand, initial adhesion was evaluated as follows. First, each of the electrical storage device exterior materials obtained in Examples 1 and 2 and Comparative Examples 1 to 4 was cut into 15 mm (TD) and 100 mm (MD) sizes to obtain test pieces. Next, the heat-fusible resin layer and the barrier layer of the test piece are separated, and the heat-fusible resin layer and the barrier layer are separated using a tensile tester (trade name: AGS-XPlus manufactured by Shimadzu Corporation). The test piece was pulled in the direction of 180° at a distance of 50 mm at a speed of 50 mm/min, and the peel strength (N/15 mm) of the test piece was measured as the initial adhesion. Table 1 shows the results. When the heat-fusible resin layer and the barrier layer are separated, the adhesive layer positioned between these layers is in a state of being laminated on either or both of the heat-fusible resin layer and the barrier layer. becomes.

<Tensile breaking strength of base material layer>
For the biaxially oriented polyethylene terephthalate film used as the base layer in Examples 1 and 2 and the biaxially oriented nylon film used as the base layer in Comparative Examples 1 and 2, the longitudinal direction (MD) and the transverse direction ( TD) is measured using a tensile tester (AG-Xplus (trade name) manufactured by Shimadzu Corporation). The measurement conditions were a rectangular sample with a width of 15 mm, a distance between gauge lines of 50 mm, a tensile speed of 50 mm/min, and a test environment of 23°C. Table 1 shows the results.

In Table 1, PET is a polyethylene terephthalate film, DL is an adhesive layer or adhesive layer formed by a dry lamination method, ALM is an aluminum alloy foil, PPa is maleic anhydride-modified polypropylene, PP is polypropylene, and CPP is an unstretched laminate. A polypropylene film, Ny means a nylon film, and AD means an adhesive layer between PET and Ny. Further, the numerical value given to each layer means the thickness (μm), for example, the notation “PET25” means “a polyethylene terephthalate film with a thickness of 25 μm”.

As is clear from the results shown in Table 1, the substrate layer is composed of a single-layer polyester film, and at least one surface of the barrier layer is provided with a corrosion-resistant film. When analyzed using time-of-flight secondary ion mass spectrometry, the ^ratio P _PO3 /P _CePO4 of the peak intensity P _PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO _{4 −} was 80. Although the exterior materials for electric storage devices of Examples 1 and 2 in the range of ~120 have a corrosion-resistant film on the surface of the barrier layer, they are heat-sealed with the barrier layer after immersion in the electrolyte. It can be seen that the adhesiveness between the adhesive layer and the adhesive resin layer is excellent.

As described above, the present disclosure provides inventions in the following aspects.
Section 1. Consists of a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order,
The base material layer is composed of a single-layer polyester film,
At least one surface of the barrier layer is provided with a corrosion-resistant coating,
When the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the ratio of the peak intensity P PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO ₄ ⁻ is _{P PO3 /} An exterior material for an electricity storage device, wherein P _CePO4 is in the range of 80 or more and 120 or less.
Section 2. Item 2. The exterior material for an electricity storage device according to Item 1, wherein the corrosion-resistant film is provided on at least the surface of the barrier layer on the side of the heat-fusible resin layer.
Item 3. Item 3. The exterior material for an electricity storage device according to Item 2, wherein the corrosion-resistant film and the heat-sealable resin layer are laminated via an adhesive layer.
Section 4. Item 4. The exterior material for an electricity storage device according to Item 3, wherein the resin forming the adhesive layer has a polyolefin skeleton.
Item 5. Item 5. The exterior material for an electricity storage device according to Item 3 or 4, wherein the adhesive layer contains an acid-modified polyolefin.
Item 6. Item 6. The power storage device exterior material according to any one of Items 3 to 5, wherein a peak derived from maleic anhydride is detected when the adhesive layer is analyzed by infrared spectroscopy.
Item 7. The acid-modified polyolefin of the adhesive layer is maleic anhydride-modified polypropylene,
Item 7. The exterior material for an electricity storage device according to Item 6, wherein the heat-fusible resin layer contains polypropylene.
Item 8. Any of items 3 to 7, wherein the adhesive layer 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 a compound having an epoxy group. The exterior material for an electricity storage device according to any one of the above.
Item 9. Item 3, wherein the adhesive layer is a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocyclic ring, a C═N bond, and a C—O—C bond. 9. The exterior material for an electricity storage device according to any one of -8.
Item 10. Item 10. The power storage device exterior material according to any one of Items 3 to 9, wherein the adhesive layer contains at least one selected from the group consisting of urethane resins, ester resins, and epoxy resins.
Item 11. Item 11. The exterior material for an electricity storage device according to any one of Items 1 to 10, wherein the barrier layer is made of an aluminum alloy foil.
Item 12. Item 12. The power storage device exterior material according to any one of Items 1 to 11, wherein the resin constituting the heat-fusible resin layer contains a polyolefin skeleton.
Item 13. Item 13. The exterior material for an electricity storage device according to any one of Items 1 to 12, which is a packaging material used for an electricity storage device of a mobile device.
Item 14. At least a step of laminating a substrate layer, a barrier layer, and a heat-fusible resin layer in this order to obtain a laminate,
The base material layer is composed of a single-layer polyester film,
At least one surface of the barrier layer is provided with a corrosion-resistant coating,
When the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the ratio of the peak intensity P PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO ₄ ⁻ is _{P PO3 /} A method for producing an exterior material for an electricity storage device, wherein P _CePO4 is in the range of 80 or more and 120 or less.
Item 15. Item 14. 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 of the electricity storage device exterior material according to any one of Items 1 to 13.

REFERENCE SIGNS LIST 1 Base layer 2 Adhesive layer 3 Barrier layers 3a, 3b Corrosion-resistant film 4 Heat-fusible resin layer 5 Adhesive layer 6 Surface coating layer 10 Exterior material for power storage device

Claims (15)

Consists of a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order,
The base material layer is composed of a single-layer polyester film,
At least one surface of the barrier layer is provided with a corrosion-resistant coating,
When the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the ratio of the peak intensity P PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO ₄ ⁻ is _{P PO3 /} An exterior material for an electricity storage device, wherein P _CePO4 is in the range of 80 or more and 120 or less. 2. The exterior material for an electricity storage device according to claim 1, wherein said corrosion-resistant film is provided on at least the surface of said barrier layer on the side of said heat-fusible resin layer. 3. The exterior material for an electricity storage device according to claim 2, wherein said corrosion-resistant film and said heat-sealable resin layer are laminated via an adhesive layer. 4. The power storage device exterior material according to claim 3, wherein the resin forming said adhesive layer has a polyolefin skeleton. 5. The power storage device exterior material according to claim 3, wherein the adhesive layer contains an acid-modified polyolefin. The power storage device exterior material according to any one of claims 3 to 5, wherein when the adhesive layer is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is detected. The acid-modified polyolefin of the adhesive layer is maleic anhydride-modified polypropylene,
The exterior material for an electricity storage device according to claim 5 , wherein the heat-fusible resin layer contains polypropylene. The adhesive layer 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 a compound having an epoxy group. The exterior material for an electricity storage device according to any one of the above. The adhesive layer is a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of oxygen atoms, heterocycles, C═N bonds, and C—O—C bonds. 9. The exterior material for an electricity storage device according to any one of 3 to 8. The power storage device exterior material according to any one of claims 3 to 9, wherein the adhesive layer contains at least one selected from the group consisting of urethane resins, ester resins, and epoxy resins. The exterior material for an electricity storage device according to any one of claims 1 to 10, wherein the barrier layer is made of an aluminum alloy foil. The exterior material for an electricity storage device according to any one of claims 1 to 11, wherein the resin forming the heat-fusible resin layer contains a polyolefin skeleton. The exterior material for an electricity storage device according to any one of claims 1 to 12, which is a packaging material used for an electricity storage device of a mobile device. At least a step of laminating a substrate layer, a barrier layer, and a heat-fusible resin layer in this order to obtain a laminate,
The base material layer is composed of a single-layer polyester film,
At least one surface of the barrier layer is provided with a corrosion-resistant coating,
When the corrosion-resistant film is analyzed using time-of-flight secondary ion mass spectrometry, the ratio of the peak intensity P PO3 derived from PO ₃ ⁻ to the peak intensity P _CePO4 derived from CePO ₄ ⁻ is _{P PO3 /} A method for producing an exterior material for an electricity storage device, wherein P _CePO4 is in the range of 80 or more and 120 or less. 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 claims 1 to 13.

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