WO2021020583A1

WO2021020583A1 - Exterior material for electrical storage device, method for manufacturing same, and electrical storage device

Info

Publication number: WO2021020583A1
Application number: PCT/JP2020/029576
Authority: WO
Inventors: 立沢　雅博; 純景山
Original assignee: 大日本印刷株式会社
Priority date: 2019-08-01
Filing date: 2020-07-31
Publication date: 2021-02-04
Also published as: JPWO2021020583A1; JP2021182550A; CN114175369A; JP7055904B2

Abstract

This exterior material for an electrical storage device is composed of a stack comprising at least, in this order from an outer side, a surface coating layer, a base material layer, a barrier layer, and a thermal adhesive resin layer. The surface coating layer includes a resin and particles, wherein, with respect to a cross section in a thickness direction of the surface coating layer, the hardness of the resin in the surface coating layer as measured by nanoindentation technique in a 23°C environment is not more than 420.4 MPa.

Description

Exterior materials for power storage devices, their manufacturing methods, and power storage devices

This disclosure relates to an exterior material for a power storage device, a manufacturing method thereof, and a power storage device.

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

On the other hand, in recent years, with the improvement of high performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., various shapes are required for power storage devices, and thinning and weight reduction are required. However, the metal exterior material for a power storage device, which has been widely used in the past, has a drawback that it is difficult to keep up with the diversification of shapes and there is a limit to weight reduction.

Therefore, in recent years, as an exterior material for a power storage device that can be easily processed into various shapes and can be made thinner and lighter, it is in the form of a film in which a base material layer / barrier layer / thermosetting resin layer is sequentially laminated. Laminates have been proposed (see, for example, Patent Document 1).

In such an exterior material for a power storage device, a recess is generally formed by cold molding, and a storage device element such as an electrode or an electrolytic solution is arranged in the space formed by the recess to form a thermosetting resin. By heat-sealing (heat sealing) the layers, a power storage device in which the power storage device element is housed inside the exterior material for the power storage device can be obtained.

Japanese Unexamined Patent Publication No. 2008-287971

In an exterior material for a power storage device composed of a film-like laminate, a surface coating layer containing particles may be provided on the outside of the base material layer in order to make the outer surface a matte design (mat).

However, as described above, since the exterior material for a power storage device is used for molding, excellent moldability is also required for the exterior material for a power storage device provided with a surface coating layer containing particles. Specifically, it is required to suppress the occurrence of cracking and peeling of the surface coating layer by molding the exterior material for the power storage device.

Under such circumstances, the main object of the present disclosure is to provide an exterior material for a power storage device in which the occurrence of cracking or peeling of the surface coating layer due to molding of the exterior material for the power storage device is suppressed.

The inventors of the present disclosure have made diligent studies to solve the above problems. As a result, the exterior material for a power storage device is composed of a laminate including at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealing resin layer in order from the outside, and the surface coating layer is a resin. And particles, and the hardness of the resin of the surface coating layer measured by the nanoindentation method is 420.4 MPa or less with respect to the cross section in the thickness direction of the surface coating layer in an environment of 23 ° C. It has been found that the exterior material for use suppresses the occurrence of cracking and peeling of the surface coating layer due to the molding of the exterior material for power storage devices.

The present disclosure has been completed by further studies based on these findings. That is, the present disclosure provides the inventions of the following aspects.
From the outside, it is composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer.
The surface coating layer contains resin and particles, and contains resin and particles.
An exterior material for a power storage device in which the hardness of the resin of the surface coating layer measured by the nanoindentation method with respect to the cross section in the thickness direction of the surface coating layer in an environment of 23 ° C. is 420.4 MPa or less.

According to the present disclosure, it is possible to provide an exterior material for a power storage device that suppresses the occurrence of cracking or peeling of the surface coating layer due to molding of the exterior material for the power storage device. Further, according to the present disclosure, it is also possible to provide a method for manufacturing the exterior material for the power storage device and a power storage device using the exterior material for the power storage device.

It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure.

The exterior material for a power storage device of the present disclosure is composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer in this order from the outside, and the surface coating layer is a resin. The hardness of the resin of the surface coating layer measured by the nanoindentation method is 420.4 MPa or less with respect to the cross section in the thickness direction of the surface coating layer in an environment of 23 ° C. It is a feature. Since the exterior material for a power storage device of the present disclosure has such a configuration, the occurrence of cracking or peeling of the surface coating layer due to molding of the exterior material for a power storage device is suppressed.

Hereinafter, the exterior material for the power storage device of the present disclosure will be described in detail. In this specification, the numerical range indicated by "-" means "greater than or equal to" and "less than or equal to". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. 1. Laminated structure and physical properties of the exterior material for the power storage device The exterior material 10 for the power storage device of the present disclosure includes, for example, the surface coating layer 6, the base material layer 1, and the barrier layer 3 in this order from the outside, as shown in FIGS. 1 to 3. It is composed of a laminate including the heat-sealing resin layer 4 and the heat-sealing resin layer 4. In the exterior material 10 for a power storage device, the surface coating layer 6 is the outermost layer, and the thermosetting resin layer 4 is the innermost layer. When assembling a power storage device using the power storage device exterior material 10 and the power storage device element, the peripheral portion is heat-sealed with the thermosetting resin layers 4 of the power storage device exterior material 10 facing each other. The power storage device element is housed in the space formed by. In the laminate constituting the exterior material 10 for the power storage device of the present disclosure, the heat-sealing resin layer 4 side is inside the barrier layer 3 and the surface coating layer 6 side is more than the barrier layer 3 with the barrier layer 3 as a reference. It is the outside.

As shown in FIGS. 2 to 3, for example, the exterior material 10 for a power storage device is used, if necessary, for the purpose of enhancing the adhesiveness between the base material layer 1 and the barrier layer 3 and the like. It may have an adhesive layer 2. Further, although not shown, a colored layer may be provided between the base material layer 1 and the barrier layer 3. Further, for example, as shown in FIG. 3, an adhesive layer 5 is provided between the barrier layer 3 and the thermosetting resin layer 4 as necessary for the purpose of enhancing the adhesiveness between the layers. You may be.

The thickness of the laminate constituting the exterior material 10 for the power storage device is not particularly limited, but is preferably about 180 μm or less, about 160 μm or less, about 155 μm or less, about 140 μm or less from the viewpoint of cost reduction, energy density improvement, and the like. , About 130 μm or less, about 120 μm or less, and preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, about 80 μm or more from the viewpoint of maintaining the function of the exterior material for the power storage device of protecting the power storage device element. The preferred range is, for example, about 35 to 180 μm, about 35 to 160 μm, about 35 to 155 μm, about 35 to 140 μm, about 35 to 130 μm, about 35 to 120 μm, about 45 to 180 μm, about 45 to 160 μm. , 45 to 155 μm, 45 to 140 μm, 45 to 130 μm, 45 to 120 μm, 60 to 180 μm, 60 to 160 μm, 60 to 155 μm, 60 to 140 μm, 60 to 130 μm, 60 to 120 μm. , About 80 to 180 μm, about 80 to 160 μm, about 80 to 155 μm, about 80 to 140 μm, about 80 to 130 μm, about 80 to 120 μm. Among these, about 80 to 130 μm is particularly preferable.

In the exterior material 10 for a power storage device of the present disclosure, the hardness of the resin of the surface coating layer measured by the nanoindentation method is 420.4 MPa or less with respect to the cross section of the surface coating layer 6 in the thickness direction in an environment of 23 ° C. Is. In the exterior material 10 for a power storage device, the surface coating layer 6 has the above-mentioned hardness in an environment of 23 ° C., so that the surface coating layer is cracked or peeled off by molding the exterior material for a power storage device in a normal temperature environment. Occurrence is suppressed.

From the viewpoint of more effectively suppressing the occurrence of cracking and peeling of the surface coating layer due to the molding of the exterior material for the power storage device, the exterior material 10 for the power storage device of the present disclosure is the surface coating layer 6 in an environment of 23 ° C. With respect to the cross section in the thickness direction, the hardness of the resin of the surface coating layer 6 measured by the nanoindentation method is preferably about 350.4 MPa or less, more preferably about 310.4 MPa or less, and preferably about 20. It is 0.0 MPa or more, more preferably about 22.5 MPa or more, still more preferably about 25.5 MPa or more, still more preferably about 50.0 MPa or more, still more preferably about 100.0 MPa or more, still more preferably about 150.0 MPa or more. The preferred range is about 20.0 to 420.4 MPa, about 20.0 to 350.4 MPa, about 20.0 to 310.4 MPa, about 22.5 to 420.4 MPa, and about 22.5 to 350.4 MPa. , 22.5 to 310.4 MPa, 25.5 to 420.4 MPa, 25.5 to 350.4 MPa, 25.5 to 310.4 MPa, 50.0 to 420.4 MPa, 50.0 to About 350.4 MPa, about 50.0 to 310.4 MPa, about 100.0 to 420.4 MPa, about 100.0 to 350.4 MPa, about 100.0 to 310.4 MPa, about 150.0 to 420.4 MPa, Examples thereof include about 150.0 to 350.4 MPa and about 150.0 to 310.4 MPa. Among these, about 150.0 to 310.4 MPa is particularly preferable. In the present invention, excellent moldability means that, more specifically, the matte design of the surface coating layer is impaired by molding the exterior material 10 for a power storage device, and the surface is molded at room temperature. It means that the occurrence of cracks and peeling in the coating layer is suppressed. The hardness measured by the nanoindentation method in a 23 ° C. environment is measured as follows.

[Hardness measured by nanoindentation method in 23 ° C environment]
Hardness is measured using a nanoindenter (for example, "TI950 TriboIndenter" manufactured by HYSITRON) as an apparatus. As the indenter of the nano indenter, a Berkovich indenter (for example, TI-0039) is used. First, in an environment with a relative humidity of 50% and 23 ° C., the indenter is applied to the surface of the surface coating layer of the exterior material for a power storage device (the surface on which the surface coating layer is exposed and parallel to the thickness direction of each layer). The indenter is pushed into the surface coating layer from the surface to a load of 50 μN over 10 seconds, held in that state for 5 seconds, and then unloaded over 10 seconds. The average value of N = 5 measured by shifting the measurement points is defined as the hardness. The surface on which the indenter is pushed is a resin portion having an exposed cross section of the surface coating layer obtained by cutting in the thickness direction so as to pass through the central portion of the exterior material for a power storage device. Cutting is performed using a commercially available rotary microtome. Further, when the exterior material for a power storage device is acquired from the power storage device and a test sample is prepared, the exterior material for the power storage device is acquired from a place such as the top surface or the side surface of the power storage device that is less affected by molding.

The hardness measured by the nanoindentation method in an environment of 23 ° C. is the composition (resin type, content), curing conditions, molecular weight, number of functional groups, and crosslink density of the resin composition forming the surface coating layer 6. , The bulkiness of the substituent can be adjusted.

2. 2. Each layer forming the exterior material for the power storage device [Surface coating layer 6]
The exterior material 10 for a power storage device of the present disclosure has a surface coating layer 6 on the outside of the base material layer 1 for the purpose of imparting a matte design to the outer surface of the exterior material 10 for a power storage device. There is. The surface coating layer 6 is a layer located on the outermost layer of the exterior material 10 for a power storage device when the power storage device is assembled using the exterior material 10 for the power storage device.

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

The average particle size of the particles is not particularly limited, but from the viewpoint of making the exterior material 10 for a power storage device a matte design, for example, about 0.01 to 5 μm can be mentioned. The average particle size of the particles is the median size measured by a laser diffraction / scattering type particle size distribution measuring device. The average particle size of the particles is preferably equal to or less than the thickness of the surface coating layer 6.

The inorganic particles are not particularly limited as long as the surface coating layer 6 can be made matte, and for example, silica, talc, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, etc. Magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, stearer Particles such as magnesium acid, alumina, carbon black, carbon nanotubes, gold, aluminum, copper and nickel can be mentioned. Among these, silica particles are particularly preferable.

The organic particles are not particularly limited as long as the surface coating layer 6 can be made matte, such as nylon, polyacrylate, polystyrene, styrene-acrylic copolymer, polyethylene, benzoguanamine, or crosslinked products thereof. Particles can be mentioned.

In the above-mentioned measurement of [hardness measured by the nanoindentation method in a 23 ° C. environment], the surface on which the indenter is pushed is cut in the thickness direction so as to pass through the central portion of the exterior material for a power storage device. Further, the hardness of the organic particles contained in the surface coating layer 6 can be measured by setting the cross section of the surface coating layer as a place where the exposed organic particles are present. From the viewpoint of more effectively suppressing the occurrence of cracking and peeling of the surface coating layer due to the molding of the exterior material for the power storage device, the hardness of the organic particles measured in this way is preferably about 300.0 MPa or more. , More preferably about 400.0 MPa or more, preferably about 1500.4 MPa or less, more preferably about 1000.4 MPa or less, still more preferably about 600.4 MPa or less, and the preferred range is 300.0 MPa or less. ~ 1500.4 MPa, 300.0 ~ 1000.4 MPa, 300.0 ~ 600.4 MPa, 400.0 ~ 1500.4 MPa, 400.0 ~ 1000.4 MPa, 400.0 ~ 600.4 MPa Among these, about 400.0 to 600.4 MPa is particularly preferable.

The content of the particles contained in the surface coating layer 6 is not particularly limited as long as the hardness measured by the nanoindentation method in an environment of 23 ° C. is 420.4 MPa or less, but the surface coating layer is not particularly limited. With respect to 100 parts by mass of the resin in the resin composition forming 6, it is preferably about 3 parts by mass or more, more preferably about 10 parts by mass or more, and preferably about 30 parts by mass or less, more preferably about about. It is 20 parts by mass or less, and preferred ranges include about 3 to 30 parts by mass, about 3 to 20 parts by mass, about 10 to 30 parts by mass, and about 10 to 20 parts by mass.

If the amount of particles present in the surface coating layer 6 is too large, the adhesion between the resin and the particle boundary is weak and cracks are likely to occur from the boundary. Therefore, it is preferable to adjust the particle content to be small.

The resin contained in the resin composition forming the surface coating layer 6 is not particularly limited as long as the hardness measured by the nanoindentation method in an environment of 23 ° C. is 420.4 MPa or less. A curable resin is preferable. That is, the surface coating layer 6 is preferably composed of a cured product of a resin composition containing a curable resin and particles. Specific examples of the resin include resins such as polyvinylidene chloride, polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, and phenol resin, and modified products of these resins. Further, it may be a copolymer of these resins, or it may be a modified product of the copolymer. Further, it may be a mixture of these resins. The resin is preferably a curable resin.

The curable resin may be either a one-component curing type or a two-component curing type, but is preferably a two-component curing type. Examples of the two-component curable resin include two-component curable polyurethane, two-component curable polyester, and two-component curable epoxy resin. Of these, two-component curable polyurethane is preferable.

Examples of the two-component curable polyurethane include polyurethane containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred are two-component curable polyurethanes in which a polyol such as a polyester polyol, a polyether polyol, and an acrylic polyol is used as a main component, and an aromatic or aliphatic polyisocyanate is used as a curing agent. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in the side chain in addition to the hydroxyl group at the end of the repeating unit. Examples of the curing agent include aliphatic, alicyclic, aromatic, and aromatic aliphatic isocyanate compounds. Examples of isocyanate-based compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate. (MDI), naphthalenediocyanate (NDI) and the like. Moreover, a polyfunctional isocyanate modified product from one kind or two or more kinds of these diisocyanates and the like can be mentioned. Further, a multimer (for example, a trimer) can be used as the polyisocyanate compound. Examples of such a multimer include an adduct body, a biuret body, a nurate body and the like. The aliphatic isocyanate-based compound refers to an isocyanate having an aliphatic group and no aromatic ring, and the alicyclic isocyanate-based compound refers to an isocyanate having an alicyclic hydrocarbon group, which is an aromatic isocyanate-based compound. Refers to an isocyanate having an aromatic ring.

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

On at least one of the surface and the inside of the surface coating layer 6, depending on the functionality and the like to be provided on the surface coating layer 6 and the surface thereof, if necessary, a lubricant, a colorant, an antiblocking agent, and a difficulty described later will be provided. Additives such as flame retardants, antioxidants, tackifiers, antistatic agents, waxes and the like may be further included.

When the surface coating layer 6 contains a colorant, known colorants such as pigments and dyes can be used as the colorant. Further, 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 surface coating layer 6 include the same as those exemplified in the column of [Adhesive layer 2]. Further, the preferable content of the colorant contained in the surface coating layer 6 is the same as the content described in the column of [Adhesive layer 2].

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

If the amount of the additive present in the surface coating layer 6 is too large, the adhesion between the resin and the attachment is weak and cracks are likely to occur from the boundary. Therefore, the content of the additive should be adjusted to the minimum necessary. preferable.

The thickness of the surface coating layer 6 is preferably 0.5 μm or more, more preferably 1 μm or more, from the viewpoint of more effectively suppressing the occurrence of cracking and peeling of the surface coating layer due to molding of the exterior material for the power storage device. Yes, it is preferably 10 μm or less, more preferably 5 μm or less, and preferred ranges include about 0.5 to 10 μm, about 0.5 to 5 μm, about 1 to 10 μm, and about 1 to 5 μm.

In the present disclosure, from the viewpoint of enhancing the moldability of the exterior material for the power storage device, it is preferable that the lubricant is present on the surface of the surface coating layer 6. The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, bechenic acid amide, hydroxystearic acid amide and the like. Specific examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucate amide and the like. Further, specific examples of methylolamide include methylolstearic acid amide. Specific examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide, and hexamethylene bisstearate. Examples thereof include acid amides, hexamethylene bisbechenic acid amides, hexamethylene hydroxystearic acid amides, N, N'-distearyl adipate amides, and N, N'-distealyl sebasic acid amides. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N, N'-diorail adipate amide, and N, N'-diorail sebacic acid amide. And so on. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate and the like. Specific examples of the aromatic bisamide include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N, N'-distearyl isophthalic acid amide. One type of lubricant may be used alone, or two or more types may be used in combination.

When the lubricant is present on the surface of the surface coating layer 6, the abundance thereof is not particularly limited, but is preferably about 3 mg / m ² or more, more preferably about 4 to 15 mg / m ² , and further preferably 5 to 14 mg. / M ² is mentioned.

The lubricant existing on the surface of the surface coating layer 6 may be one in which the lubricant contained in the surface coating layer 6 is exuded, or may be one in which the lubricant is applied to the surface of the surface coating layer 6.

[Base material layer 1]
In the present disclosure, the base material layer 1 is a layer provided for the purpose of exerting a function as a base material of an exterior material for a power storage device. The base material layer 1 is located between the surface coating layer 6 and the barrier layer 3 of the exterior material 10 for a power storage device. When the adhesive layer 2 is provided, it is located between the surface coating layer 6 and the adhesive layer 2.

The material forming the base material layer 1 is not particularly limited as long as it has a function as a base material, that is, at least an insulating property. The base material layer 1 can be formed using, for example, a resin, and the resin may contain an additive described later.

When the base material layer 1 is made of resin, the base material layer 1 may be, for example, a resin film formed of resin or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferable. Examples of the stretching method for forming the biaxially stretched film include a sequential biaxial stretching method, an inflation method, and a simultaneous biaxial stretching method. Examples of the method for applying the resin include a roll coating method, a gravure coating method, and an extrusion coating method.

Examples of the resin forming the base material layer 1 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, and phenol resin, and modified products of these resins. Further, the resin forming the base material layer 1 may be a copolymer of these resins, or may be a modified product of the copolymer. Further, it may be a mixture of these resins.

Among these, preferable examples of the resin forming the base material layer 1 include polyester and polyamide.

Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester. Further, examples of the copolymerized polyester include a copolymerized polyester containing ethylene terephthalate as a repeating unit. Specifically, a copolymer polyester (hereinafter abbreviated after polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / terephthalate /), which polymerizes with ethylene isophthalate using ethylene terephthalate as a repeating unit as a main component. (Sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decandicarboxylate) and the like. These polyesters may be used alone or in combination of two or more.

Further, as the polyamide, specifically, an aliphatic polyamide such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, a copolymer of nylon 6 and nylon 66; terephthalic acid and / or isophthalic acid. Hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamide such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I stands for isophthalic acid, T stands for terephthalic acid), polyamide MXD6 (polymethaki) containing the derived structural units. Polyamide containing aromatics such as silylene adipamide); Alicyclic polyamide such as polyamide PACM6 (polybis (4-aminocyclohexyl) methaneadipamide); Further, lactam component and isocyanate component such as 4,4'-diphenylmethane-diisocyanate Examples thereof include a copolymerized polyamide, a polyesteramide copolymer or a polyether esteramide copolymer which is a copolymer of a copolymerized polyamide and a polyester or a polyalkylene ether glycol; and a polyamide such as these copolymers. These polyamides may be used alone or in combination of two or more.

The base material layer 1 preferably contains at least one of a polyester film, a polyamide film, and a polyolefin film, and preferably contains at least one of a stretched polyester film, a stretched polypropylene film, and a stretched polyolefin film. It is more preferable to contain at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film, preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, and a biaxially stretched nylon film. , It is more preferable to contain at least one of the biaxially stretched polypropylene films.

The base material layer 1 may be a single layer or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminated body in which a resin film is laminated with an adhesive or the like, or the resin is co-extruded to form two or more layers. It may be a laminated body of the resin film. Further, the laminated body of the resin film obtained by co-extruding the resin into two or more layers may be used as the base material layer 1 without being stretched, or may be uniaxially stretched or biaxially stretched as the base material layer 1.

Specific examples of the laminate of two or more layers of resin film in the base material layer 1 include a laminate of a polyester film and a nylon film, a laminate of two or more layers of nylon film, and a laminate of two or more layers of polyester film. And the like, preferably, a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more layers of stretched nylon film, and a laminate of two or more layers of stretched polyester film are preferable. For example, when the base material layer 1 is a laminate of two layers of resin film, a laminate of polyester resin film and polyester resin film, a laminate of polyamide resin film and polyamide resin film, or a laminate of polyester resin film and polyamide resin film. A laminate is preferable, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferable. Further, since the polyester resin is difficult to discolor when the electrolytic solution adheres to the surface, for example, when the base material layer 1 is a laminate of two or more resin films, the polyester resin film is the base material layer 1. It is preferably located on the outermost side.

When the base material layer 1 is a laminated body of two or more layers of resin films, the two or more layers of resin films may be laminated via an adhesive. Preferred adhesives include those similar to the adhesives exemplified in the adhesive layer 2 described later. The method of laminating two or more layers of resin films is not particularly limited, and known methods can be adopted. Examples thereof include a dry laminating method, a sandwich laminating method, an extrusion laminating method, and a thermal laminating method, and a dry laminating method is preferable. The laminating method can be mentioned. When laminating by the dry laminating method, it is preferable to use a polyurethane adhesive as the adhesive. At this time, the thickness of the adhesive is, for example, about 2 to 5 μm. Further, an anchor coat layer may be formed on the resin film and laminated. Examples of the anchor coat layer include the same adhesives as those exemplified in the adhesive layer 2 described later. At this time, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

Further, even if 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 inside of the base material layer 1. Good. Only one type of additive may be used, or two or more types may be mixed and used.

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

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

The adhesive layer 2 is formed by an adhesive capable of adhering the base material layer 1 and the barrier layer 3. The adhesive used for forming the adhesive layer 2 is not limited, but may be any of a chemical reaction type, a solvent volatile type, a heat melting type, a hot pressure type and the like. Further, it may be a two-component curable adhesive (two-component adhesive), a one-component curable adhesive (one-component adhesive), or a resin that does not involve a curing reaction. Further, the adhesive layer 2 may be a single layer or a multilayer.

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 resin; Polyethylene such as nylon 6, nylon 66, nylon 12, copolymerized polyamide; Polyethylene resin such as polyolefin, cyclic polyolefin, acid-modified polyolefin, acid-modified cyclic polyolefin; Polyvinyl acetate; Cellulose; (Meta) acrylic resin; Polyethylene; polycarbonate; amino resin such as urea resin and melamine resin; rubber such as chloroprene rubber, nitrile rubber and styrene-butadiene rubber; silicone resin and the like. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, a polyurethane adhesive is preferable. In addition, the resins used as these adhesive components can be used in combination with an appropriate curing agent to increase the adhesive strength. An appropriate curing agent is selected from polyisocyanate, polyfunctional epoxy resin, oxazoline group-containing polymer, polyamine resin, acid anhydride and the like, depending on the functional group of the adhesive component.

Examples of the polyurethane adhesive include a polyurethane adhesive containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred are two-component curable polyurethane adhesives in which a polyol such as a polyester polyol, a polyether polyol, and an acrylic polyol is used as a main component, and an aromatic or aliphatic polyisocyanate is used as a curing agent. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in the side chain in addition to the hydroxyl group at the end of the repeating unit. Examples of the curing agent include aliphatic, alicyclic, aromatic, and aromatic aliphatic isocyanate compounds. Examples of isocyanate-based compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate. (MDI), naphthalenediocyanate (NDI) and the like. Moreover, a polyfunctional isocyanate modified product from one kind or two or more kinds of these diisocyanates and the like can be mentioned. Further, a multimer (for example, a trimer) can be used as the polyisocyanate compound. Examples of such a multimer include an adduct body, a biuret body, a nurate body and the like. Since the adhesive layer 2 is formed of a polyurethane adhesive, excellent electrolyte resistance is imparted to the exterior material for the power storage device, and even if the electrolyte adheres to the side surface, the base material layer 1 is suppressed from peeling off. ..

Further, the adhesive layer 2 may contain a colorant, a thermoplastic elastomer, a tackifier, particles and the like, as long as the adhesiveness is not hindered, the addition of other components is permitted. Since the adhesive layer 2 contains a colorant, the exterior material for the power storage device can be colored. As the colorant, known pigments, dyes and the like can be used. Further, 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, anthracinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindrenine-based, and benzimidazolone-based pigments, which are inorganic. Examples of the pigment include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, and other examples include fine powder of mica (mica) and fish scale foil.

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

The average particle size of the pigment is not particularly limited, and examples thereof include about 0.05 to 5 μm, preferably about 0.08 to 2 μm. The average particle size of the pigment is the median diameter measured by a laser diffraction / scattering type particle size distribution measuring device.

The content of the pigment in the adhesive layer 2 is not particularly limited as long as the exterior material for the power storage device is colored, and examples thereof include 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 base material layer 1 and the barrier layer 3 can be adhered to each other, and examples thereof include about 1 μm or more and about 2 μm or more. The thickness of the adhesive layer 2 is, for example, about 10 μm or less and about 5 μm or less. The preferable range of the thickness of the adhesive layer 2 is about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

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

The colored layer can be formed, for example, by applying an ink containing a colorant to the surface of the base material layer 1 or the surface of the barrier layer 3. As the colorant, known pigments, dyes and the like can be used. Further, 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 include the same as those exemplified in the column of [Adhesive layer 2].

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

Examples of the barrier layer 3 include a metal foil having a barrier property, a thin-film deposition film, a resin layer, and the like. Examples of the vapor deposition film include a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, and the like, and examples of the resin layer include polymers and tetras mainly composed of polyvinylidene chloride and chlorotrifluoroethylene (CTFE). Examples thereof include 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. Further, examples of the barrier layer 3 include a resin film provided with at least one of these vapor-deposited films and a resin layer. A plurality of barrier layers 3 may be provided. The barrier layer 3 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include an aluminum alloy, stainless steel, titanium steel, and a steel plate. When used as a metal foil, the metal material includes at least one of an aluminum alloy foil and a stainless steel foil. Is preferable.

The aluminum alloy foil is more preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy from the viewpoint of suppressing the occurrence of pinholes and cracks during molding of the exterior material for a power storage device. From the viewpoint of more effectively suppressing the occurrence of pinholes and cracks during molding, an aluminum alloy foil containing iron is preferable. In the aluminum alloy foil containing iron (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, and 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 a power storage device in which the occurrence of pinholes and cracks during molding is effectively suppressed. When the iron content is 9.0% by mass or less, a more flexible exterior material for a power storage device can be obtained. As the soft aluminum alloy foil, for example, an aluminum alloy having a composition specified by JIS H4160: 1994 A8021HO, JIS H4160: 1994 A8079HO, JIS H4000: 2014 A8021PO, or JIS H4000: 2014 A8077P-O. Foil is mentioned. Further, if necessary, silicon, magnesium, copper, manganese and the like may be added. Further, softening can be performed by annealing or the like.

Examples of stainless steel foils include austenite-based, ferrite-based, austenite-ferritic-based, martensitic-based, and precipitation-hardened stainless steel foils. Further, from the viewpoint of suppressing the generation of pinholes and cracks during molding of the exterior material for the power storage device, 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, and SUS316L, and among these, SUS301 or SUS304 is particularly preferable.

In the case of a metal foil, the thickness of the barrier layer 3 may at least exhibit a function as a barrier layer that suppresses the infiltration of water, and is, for example, about 9 to 200 μm. The thickness of the barrier layer 3 is, for example, preferably about 85 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 3 is, for example, preferably about 10 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. The preferred range of the thickness of the barrier layer 3 is about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, and about 20 to 40 μm. Examples thereof include 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, and among these, about 25 to 40 μm is particularly preferable. When the barrier layer 3 is made of an aluminum alloy foil, the above range is particularly preferable. Further, in particular, when the barrier layer 3 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, still more preferably about. 30 μm or less, particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. The preferred thickness range of the stainless steel foil is about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, and about 15 to. Examples thereof include about 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

When the barrier layer 3 is a metal foil, it is preferable that a corrosion-resistant film is provided at least on the surface opposite to the base material layer in order to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion-resistant film on both sides. Here, the corrosion-resistant film is, for example, a hot-water transformation treatment such as boehmite treatment, a chemical conversion treatment, an anodization treatment, a plating treatment such as nickel or chromium, and a corrosion prevention treatment for applying a coating agent on the surface of the barrier layer. This is a thin film that makes the barrier layer corrosive. As the treatment for forming the corrosion-resistant film, one type may be performed, or two or more types may be combined. Moreover, not only one layer but also multiple layers can be used. Further, among these treatments, the hydrothermal modification treatment and the anodizing treatment are treatments in which the surface of the metal foil is dissolved by a treatment agent to form a metal compound having excellent corrosion resistance. Note that these processes may be included in the definition of chemical conversion process. When the barrier layer 3 has a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

The corrosion-resistant film is formed by preventing delamination between the barrier layer (for example, aluminum alloy foil) and the base material layer during molding of the exterior material for a power storage device, and by hydrogen fluoride generated by the reaction between the electrolyte and water. , Melting and corrosion of the barrier layer surface, especially when the barrier layer is an aluminum alloy foil, it prevents the aluminum oxide existing on the barrier layer surface from melting and corroding, and the adhesiveness (wetness) of the barrier layer surface. The effect of preventing delamination between the base material layer and the barrier layer during heat sealing and preventing delamination between the base material layer and the barrier layer during molding is shown.

Various corrosion-resistant films formed by chemical conversion treatment are known, and mainly, at least one of phosphate, chromate, fluoride, triazinethiol compound, and rare earth oxide. Examples include a corrosion-resistant film containing. Examples of the chemical conversion treatment using a phosphate or a chromate include a chromium acid chromate treatment, a phosphoric acid chromate treatment, a phosphoric acid-chromate treatment, a chromium salt treatment, and the like, and chromium used in these treatments. Examples of the compound include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium dichromate, acetylacetate chromate, chromium chloride, and chromium potassium sulfate. In addition, examples of the phosphorus compound used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid and the like. Further, examples of the chromate treatment include etching chromate treatment, electrolytic chromate treatment, and coating type chromate treatment, and coating type chromate treatment is preferable. In this coating type chromate treatment, at least the inner layer side surface of the barrier layer (for example, aluminum alloy foil) is first known as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activation method and the like. Degreasing is performed by the treatment method, and then metal phosphates such as Cr phosphate (chromium) salt, Ti (titanium) phosphate, Zr (zyroxide) salt, and Zn (zinc) phosphate are applied to the degreased surface. A treatment liquid containing a salt and a mixture of these non-metal salts as a main component, or a treatment liquid containing a mixture of a phosphate non-metal salt and these non-metal salts as a main component, or a synthetic resin and the like. This is a treatment in which a treatment liquid composed of a mixture is coated by a well-known coating method such as a roll coating method, a gravure printing method, or a dipping method, and dried. As the treatment liquid, for example, various solvents such as water, alcohol-based solvent, hydrocarbon-based solvent, ketone-based solvent, ester-based solvent, and ether-based solvent can be used, and water is preferable. Further, examples of the resin component used at this time include polymers such as phenolic resin and acrylic resin, and an amination phenol polymer having a repeating unit represented by the following general formulas (1) to (4) can be used. Examples thereof include the chromate treatment used. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. May be good. The acrylic resin shall be a polyacrylic acid, an acrylic acid methacrylate copolymer, an acrylic acid maleic acid copolymer, an acrylic acid styrene copolymer, or a derivative of these sodium salts, ammonium salts, amine salts, etc. Is preferable. In particular, derivatives of polyacrylic acid such as ammonium salt, sodium salt, and amine salt of polyacrylic acid are preferable. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. Further, the acrylic resin is preferably a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride, and an ammonium salt, a sodium salt, or a copolymer of an acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride. Alternatively, it is preferably an amine salt. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. Further, R ¹ and R ² represent a hydroxy group, an alkyl group, or a hydroxyalkyl group, respectively, which are the same or different. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group. Examples thereof include straight-chain or branched alkyl groups having 1 to 4 carbon atoms such as tert-butyl groups. Examples of the hydroxyalkyl groups represented by X, R ¹ and R ² include a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group and 3-. A linear or branched chain having 1 to 4 carbon atoms in which one hydroxy group such as a hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, or a 4-hydroxybutyl group is substituted. Alkyl groups can be mentioned. In the general formulas (1) to (4), the alkyl group and the hydroxyalkyl group represented by X, R ¹ and R ² may be the same or different, respectively. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having the repeating unit represented by the general formulas (1) to (4) is, for example, preferably about 5 to 1,000,000, and preferably about 1,000 to 20,000. More preferred. The amination phenol polymer, for example, polycondenses a phenol compound or a naphthol compound with formaldehyde to produce a polymer composed of repeating units represented by the above general formula (1) or general formula (3), and then formsaldehyde. It is produced by introducing a functional group (-CH ₂ NR ¹ R ² ) into the polymer obtained above using amine (R ¹ R ² NH). The aminated phenol polymer is used alone or in combination of two or more.

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

As an example of the corrosion-resistant film, a film in which fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide and barium sulfate are dispersed in phosphoric acid is applied to the surface of the barrier layer, and 150 Examples thereof include those formed by performing a baking treatment at a temperature of ° C. or higher.

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

The composition of the corrosion-resistant film can be analyzed by using, for example, a time-of-flight secondary ion mass spectrometry method.

The amount of the corrosion-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited, but for example, in the case of performing a coating type chromate treatment, a chromic acid compound per 1 m ² of the surface of the barrier layer 3 Is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of chromium, and the phosphorus compound is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of phosphorus, and an amination phenol polymer. Is preferably contained in a proportion of, for example, about 1.0 to 200 mg, preferably about 5.0 to 150 mg.

The thickness of the corrosion-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably 1 nm to 100 nm, from the viewpoint of the cohesive force of the film and the adhesion to the barrier layer and the thermosetting resin layer. The degree, more preferably about 1 nm to 50 nm. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope or a combination of observation with a transmission electron microscope and energy dispersion type X-ray spectroscopy or electron beam energy loss spectroscopy. The time-of-flight secondary ion mass spectrometry analysis of the composition of the corrosion resistant coating using, for example, secondary ion consisting Ce and P and O _{_{^{(e.g., Ce 2 PO 4 +, CePO}}} 4 - at least 1, such as species) or, for example, secondary ion of Cr and P and O (e.g., CrPO ₂ ^+, CrPO ₄ ^- peak derived from at least one), such as is detected.

In the chemical conversion treatment, a solution containing a compound used for forming a corrosion-resistant film is applied to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then the temperature of the barrier layer is applied. It is carried out by heating so that the temperature is about 70 to 200 ° C. Further, before the chemical conversion treatment is applied to the barrier layer, the barrier layer may be subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method or the like in advance. By performing the degreasing treatment in this way, it becomes possible to more efficiently perform the chemical conversion treatment on the surface of the barrier layer. Further, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for the degreasing treatment, it is possible to form not only the degreasing effect of the metal foil but also the fluoride of the metal which is immobile. In such cases, only degreasing treatment may be performed.

[Thermosetting resin layer 4]
In the exterior material for a power storage device of the present disclosure, the thermosetting resin layer 4 corresponds to the innermost layer, and has a function of heat-sealing the heat-sealing resin layers with each other when assembling the power storage device to seal the power storage device element. It is a layer (sealant layer) that exerts.

The resin constituting the heat-fusing resin layer 4 is not particularly limited as long as it can be heat-fused, but a resin containing a polyolefin skeleton such as polyolefin or acid-modified polyolefin is preferable. The fact that the resin constituting the heat-sealing resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like. Further, when the resin constituting the thermosetting resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. When the thermosetting 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 become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; homopolypropylene and block copolymers of polypropylene (for example, with propylene). Polypropylene such as (block copolymer of ethylene), random copolymer of polypropylene (for example, random copolymer of propylene and ethylene); propylene-α-olefin copolymer; terpolymer of ethylene-butene-propylene and the like. Among these, polypropylene is preferable. When it is a copolymer, the polyolefin resin may be a block copolymer or a random copolymer. One type of these polyolefin resins may be used alone, or two or more types may be used in combination.

Further, the polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and 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 the cyclic monomer which is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; cyclic diene such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkene is preferable, and norbornene is more preferable.

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

The acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin in place of the acid component, or by block-polymerizing or graft-polymerizing the acid component with the cyclic polyolefin. is there. The same applies to the cyclic polyolefins that are acid-modified. The acid component used for the acid modification is the same as the acid component used for the modification of the polyolefin.

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

The thermosetting resin layer 4 may be formed of one type of resin alone, or may be formed of a blended polymer in which two or more types of resins are combined. Further, the thermosetting resin layer 4 may be formed of only one layer, but may be formed of two or more layers with the same or different resins.

Further, the thermosetting resin layer 4 may contain a lubricant or the like, if necessary. When the thermosetting resin layer 4 contains a lubricant, it is possible to suppress the occurrence of pinholes and cracks during molding of the exterior material for the power storage device. The lubricant is not particularly limited, and a known lubricant can be used. The lubricant may be used alone or in combination of two or more.

The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the lubricant include those exemplified in the base material layer 1. One type of lubricant may be used alone, or two or more types may be used in combination.

When the lubricant is present on the surface of the thermosetting resin layer 4, the amount of the lubricant is not particularly limited, but is preferable from the viewpoint of suppressing the occurrence of pinholes and cracks during molding of the exterior material for the power storage device. Is about 10 to 50 mg / m ² , more preferably about 15 to 40 mg / m ² .

The lubricant existing on the surface of the thermosetting resin layer 4 may be one in which the lubricant contained in the resin constituting the thermosetting resin layer 4 is exuded, or the lubricant of the thermosetting resin layer 4 may be exuded. The surface may be coated with a lubricant.

The thickness of the thermosetting resin layer 4 is not particularly limited as long as the thermosetting resin layers have a function of heat-sealing to seal the power storage device element, but is preferably about 100 μm or less, preferably. It is 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 thermosetting resin layer 4 is preferably about 85 μm or less, more preferably about 15 to 45 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 thermosetting resin layer 4 is preferably about 20 μm or more, more preferably 35 to 85 μm. The degree can be mentioned.

[Adhesive layer 5]
In the exterior material for a power storage device of the present disclosure, the adhesive layer 5 is provided between the barrier layer 3 (or the acid-resistant film) and the thermosetting resin layer 4 in order to firmly bond them, if necessary. It is a layer.

The adhesive layer 5 is formed of a resin capable of adhering the barrier layer 3 and the thermosetting resin layer 4 to each other. As the resin used for forming the adhesive layer 5, for example, the same resin as the adhesive exemplified in the adhesive layer 2 can be used. The resin used for forming the adhesive layer 5 preferably contains a polyolefin skeleton, and examples thereof include the polyolefins exemplified in the above-mentioned heat-sealing resin layer 4 and acid-modified polyolefins. The fact that 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 constituting the adhesive layer 5 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

From the viewpoint of firmly adhering the barrier layer 3 and the thermosetting resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. As the acid-modified polyolefin, a polyolefin modified with a carboxylic acid or an anhydride thereof, a polypropylene modified with a carboxylic acid or an anhydride thereof, a maleic anhydride-modified polyolefin, and a maleic anhydride-modified polypropylene are particularly preferable.

Further, from the viewpoint of making the exterior material for the power storage device excellent in shape stability after molding while reducing the thickness of the exterior material for the power storage device, the adhesive layer 5 is a resin composition containing an acid-modified polyolefin and a curing agent. It is more preferable that it is a cured product of. As the acid-modified polyolefin, the above-mentioned ones are preferably exemplified.

The adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. It is particularly preferable that the resin composition is a cured product 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. Further, 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. The amide ester resin is generally produced by the reaction of a carboxyl group and an oxazoline group. The adhesive layer 5 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. When an unreacted substance of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remains in the adhesive layer 5, the presence of the unreacted substance is determined 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.

Further, from the viewpoint of further enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is selected from at least a group consisting of an oxygen atom, a heterocycle, a C = N bond, and a COC bond. It is preferably a cured product of a resin composition containing a curing agent having one type. Examples of the curing agent having a heterocycle include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C = N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C—C bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and polyurethane. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents is, for example, gas chromatograph mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF). -SIMS), X-ray photoelectron spectroscopy (XPS) and other methods can be used for confirmation.

The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferable. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include pentandiisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI), which are polymerized or nurate. Examples thereof include chemical compounds, mixtures thereof, and copolymers with other polymers. In addition, an adduct body, a burette body, an isocyanate body and the like can be mentioned.

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, and 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. More preferably in the range. As a result, the adhesion between the barrier layer 3 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 the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. In addition, examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. It is more preferable to be in. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

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

Specific examples of the epoxy resin include glycidyl ether derivative of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether and the like. One type of epoxy resin may be used alone, or two or more types may be used in combination.

The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Is more preferable. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

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

The proportion of polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and 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 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.

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 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, and about 5 μm or less. The thickness of the adhesive layer 5 is preferably about 0.1 μm or more and about 0.5 μm or more. The thickness range of the adhesive layer 5 is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, and about 0.1 to 5 μm. , About 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, and about 0.5 to 5 μm. More specifically, in the case of the adhesive exemplified in the adhesive layer 2 or the cured product of the acid-modified polyolefin and the curing agent, the thickness is preferably about 1 to 10 μm, more preferably about 1 to 5 μm. When the resin exemplified in the thermosetting resin layer 4 is used, it is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. For example, when the adhesive layer 5 is formed from acid-modified polyolefin, the thickness of the adhesive layer 5 is preferably about 2 μm or more, more preferably 5 μm or more, and further preferably 8 μm or more. Further, for example, when the adhesive layer 5 is formed from acid-modified polyolefin, the thickness of the adhesive layer 5 is preferably about 50 μm or less, more preferably 40 μm or less. Further, for example, when the adhesive layer 5 is formed from acid-modified polyolefin, the preferable range of the thickness of the adhesive layer 5 is about 2 to 50 μm, about 2 to 40 μm, about 5 to 50 μm, about 5 to 40 μm, and 8 to. It is about 50 μm and about 8 to 40 μm. When the adhesive layer 5 is a cured product of the adhesive exemplified in the adhesive layer 2 or 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. As a result, the adhesive layer 5 can be formed. Further, when the resin exemplified in the thermosetting resin layer 4 is used, it can be formed by, for example, extrusion molding of the thermosetting resin layer 4 and the adhesive layer 5.

3. 3. Method for Manufacturing Exterior Material for Power Storage Device The method for manufacturing the exterior material for power storage device is not particularly limited as long as a laminated body in which each layer of the exterior material for power storage device of the present invention is laminated can be obtained, and the method is not particularly limited. At least, there is a method including a step of obtaining a laminate in which the surface coating layer 6, the base material layer 1, the barrier layer 3, and the thermosetting resin layer 4 are laminated. Specifically, in the method for producing an exterior material for a power storage device of the present disclosure, at least a surface coating layer 6, a base material layer 1, a barrier layer 3, and a thermosetting resin layer 4 are provided in this order from the outside. The surface coating layer 6 contains a resin and particles, and the outer surface of the surface coating layer 6 is measured by a nanoindentation method in a 23 ° C. environment. Is 420.4 MPa or less.

An example of the method for manufacturing the exterior material for a power storage device of the present invention is as follows. First, a laminate in which the base material layer 1, the adhesive layer 2, and the barrier layer 3 are laminated in this order (hereinafter, may be referred to as “laminate A”) is formed. Specifically, the laminated body A is formed by applying an adhesive used for forming the adhesive layer 2 on the base material layer 1 or, if necessary, on the barrier layer 3 whose surface has been chemically converted, by a gravure coating method. It can be carried out by a dry laminating method in which the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being applied and dried by a coating method such as a roll coating method.

Next, the thermosetting resin layer 4 is laminated on the barrier layer 3 of the laminated body A. When the thermosetting resin layer 4 is directly laminated on the barrier layer 3, the thermosetting resin layer 4 is laminated on the barrier layer 3 of the laminated body A by a method such as a thermal laminating method or an extrusion laminating method. do it. When the adhesive layer 5 is provided between the barrier layer 3 and the heat-sealing resin layer 4, for example, (1) the adhesive layer 5 and the heat-sealing resin layer are placed on the barrier layer 3 of the laminated body A. A method of laminating 4 by extruding (co-extruded laminating method, tandem laminating method), (2) Separately, a laminated body in which the adhesive layer 5 and the heat-sealing resin layer 4 are laminated is formed, and this is laminated. A laminated body in which the adhesive layer 5 is laminated on the barrier layer 3 of the laminated body A is formed by a method of laminating on the barrier layer 3 of the above, and this is formed by a heat-sealing resin layer 4 and a thermal laminating method. Method of Laminating, (3) While pouring the melted adhesive layer 5 between the barrier layer 3 of the laminated body A and the heat-sealing resin layer 4 formed into a sheet in advance, the adhesive layer 5 is passed through. A method of laminating the laminate A and the heat-sealing resin layer 4 (sandwich lamination method), (4) a solution coating of an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminate A is performed. Examples thereof include a method of laminating by a method of drying, a method of baking, and the like, and a method of laminating a heat-sealing resin layer 4 having a sheet-like film formed in advance on the adhesive layer 5.

Next, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above resin composition for forming the surface coating layer 6 to the surface of the base material layer 1 and curing the surface coating layer 1. 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 base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

As described above, in order from the outside, the surface coating layer 6 / the base material layer 1 / the adhesive layer 2 provided as needed / the barrier layer 3 / the adhesive layer 5 provided as needed / the thermosetting resin. A laminated body including the layer 4 is formed, and may be further subjected to a heat treatment in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as needed. Further, as described above, a colored layer may be provided between the base material layer 1 and the barrier layer 3.

4. Applications of exterior materials for power storage devices The exterior materials for power storage devices of the present disclosure are used for packaging for sealing and accommodating power storage device elements such as positive electrodes, negative electrodes, and electrolytes. That is, a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed of the exterior material for a power storage device of the present disclosure to form a power storage device.

Specifically, a power storage device element having at least a positive electrode, a negative electrode, and an electrolyte is provided with the exterior material for the power storage device of the present disclosure in a state in which metal terminals connected to each of the positive electrode and the negative electrode are projected outward. , The peripheral edge of the power storage device element is covered so that a flange portion (a region where the heat-sealing resin layers come into contact with each other) can be formed, and the heat-sealing resin layers of the flange portion are heat-sealed and sealed. Provides a power storage device using an exterior material for the power storage device. When the power storage device element is housed in the package formed of the exterior material for the power storage device of the present disclosure, the thermosetting resin portion of the exterior material for the power storage device of the present disclosure is inside (the surface in contact with the power storage device element). ) To form a package.

The exterior material for a power storage device of the present disclosure can be suitably used for a power storage device such as a battery (including a capacitor, a capacitor, etc.). Further, the exterior material for the power storage device of the present disclosure may be used for either a primary battery or a secondary battery, but is preferably a secondary battery. The type of the secondary battery to which the exterior material for the power storage device of the present disclosure is applied is not particularly limited, and for example, a lithium ion battery, a lithium ion polymer battery, an all-solid-state battery, a lead storage battery, a nickel / hydrogen storage battery, a nickel / hydrogen battery, Examples thereof include cadmium storage batteries, nickel / iron storage batteries, nickel / zinc storage batteries, silver oxide / zinc storage batteries, metal air batteries, polyvalent cation batteries, capacitors, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are examples of suitable application targets of the exterior materials for power storage devices of the present disclosure.

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 of exterior materials for power storage devices>
[Example 1]
A stretched nylon (ONy) film (thickness 15 μm) was prepared as a base material layer. Further, as a barrier layer, an aluminum foil (JIS H4160: 1994 A8021HO (thickness 35 μm)) was prepared. Next, the barrier layer and the base material layer are laminated by a dry laminating method using an adhesive (two-component urethane adhesive containing a colorant) described later, and then an aging treatment is performed to carry out the base material layer. A laminate of / adhesive layer / barrier layer was prepared. Both sides of the aluminum foil are subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum foil is performed by applying a treatment liquid consisting of a phenol resin, a chromium fluoride compound, and phosphoric acid to both sides of the aluminum foil by a roll coating method so that the amount of chromium applied is 10 mg / m ² (dry mass). This was done by coating and baking.

Next, on the barrier layer of each of the above-mentioned laminates, maleic anhydride-modified polypropylene as an adhesive layer (thickness 20 μm) and random polypropylene as a thermosetting resin layer (thickness 20 μm) The adhesive layer / thermosetting resin layer was laminated on the barrier layer by co-extruding. Further, the surface of the base material layer of the obtained laminate is coated with the following resin composition 1 so as to have a thickness of 3 μm, and cured in an environment of a temperature of 40 ° C. to 100 ° C. for 3 days. A matte surface coating layer is formed by the above method, and the surface coating layer (3 μm) / base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (in order from the outside). An exterior material for a power storage device was obtained, which consisted of a laminated body (total thickness 96 μm) in which a heat-sealing resin layer (20 μm) was laminated (20 μm).

[Example 2]
In the formation of the surface coating layer, the following resin composition 2 was used instead of the resin composition 1, and the exterior material for the power storage device was obtained in the same manner as in Example 1 except that the surface coating layer was formed. ..

[Example 3]
In the formation of the surface coating layer, the following resin composition 3 was used instead of the resin composition 1, and an exterior material for a power storage device was obtained in the same manner as in Example 1 except that the surface coating layer was formed. ..

[Example 4]
In the formation of the surface coating layer, an exterior material for a power storage device was obtained in the same manner as in Example 1 except that the following resin composition 4 was used instead of the resin composition 1 to form the surface coating layer. ..

[Example 5]
In the formation of the surface coating layer, the following resin composition 5 was used instead of the resin composition 1, and an exterior material for a power storage device was obtained in the same manner as in Example 1 except that the surface coating layer was formed. ..

[Example 6]
In the formation of the surface coating layer, an exterior material for a power storage device was obtained in the same manner as in Example 1 except that the following resin composition 6 was used instead of the resin composition 1 to form the surface coating layer. ..

[Example 7]
In the formation of the surface coating layer, the following resin composition 7 was used instead of the resin composition 1, and an exterior material for a power storage device was obtained in the same manner as in Example 1 except that the surface coating layer was formed. ..

[Example 8]
A stretched nylon (ONy) film (thickness 12 μm) was prepared as a base material layer. Further, as a barrier layer, a stainless steel foil (SUS301 (thickness 20 μm)) was prepared. Next, the barrier layer and the base material layer are laminated by a dry laminating method using an adhesive (two-component urethane adhesive containing a colorant) described later, and then an aging treatment is performed to carry out the base material layer. A laminate of / adhesive layer / barrier layer was prepared. Both sides of the stainless steel foil are subjected to chemical conversion treatment. The chemical conversion treatment of the stainless steel foil is performed by applying a treatment liquid consisting of a phenol resin, a chromium fluoride compound, and phosphoric acid to the stainless steel foil by a roll coating method so that the amount of chromium applied is 10 mg / m ² (dry mass). This was done by applying and baking on both sides.

Next, the barrier layer and the thermosetting resin layer of each of the above-mentioned laminates are bonded by a dry laminating method using a modified olefin adhesive (the thickness of the adhesive layer after curing is 3 μm). An adhesive layer and a thermosetting resin layer were laminated on the barrier layer. As the thermosetting resin layer, an unstretched polypropylene film (thickness 23 μm) was used. Further, the surface of the base material layer of the obtained laminate is coated with the following resin composition 2 so as to have a thickness of 3 μm, and cured in an environment of a temperature of 40 ° C. to 100 ° C. for 3 days. A matte surface coating layer is formed by the above method, and the surface coating layer (3 μm) / base material layer (thickness 12 μm) / adhesive layer (3 μm) / barrier layer (20 μm) / adhesive layer (in order from the outside). An exterior material for a power storage device made of a laminated body (total thickness 64 μm) in which a heat-sealing resin layer (23 μm) was laminated (3 μm) was obtained.

[Example 9]
In the formation of the surface coating layer, an exterior material for a power storage device was obtained in the same manner as in Example 8 except that the following resin composition 9 was used instead of the resin composition 2 to form the surface coating layer. ..

[Example 10]
In the formation of the surface coating layer, the following resin composition 10 was used instead of the resin composition 1, and an exterior material for a power storage device was obtained in the same manner as in Example 1 except that the surface coating layer was formed. ..

[Comparative Example 1]
In the formation of the surface coating layer, the following resin composition 8 was used instead of the resin composition 1, and an exterior material for a power storage device was obtained in the same manner as in Example 1 except that the surface coating layer was formed. ..

<Resin composition and formation conditions used to form the surface coating layer>
(Resin composition 1 (used in Example 1))
Resin (polyurethane formed from a mixture of two polyol compounds and aromatic isocyanate compounds), inorganic particles (silica particle average particle size 1 μm), polystyrene organic particles (average particle size 2 μm), and olefin type Resin composition containing wax

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

(Resin composition 3 (used in Example 3))
Resin (polyurethane formed from a mixture of two types of polyol compound and aromatic isocyanate compound (the compounding ratio of the two types of polyol compounds is changed from resin composition 1)) and inorganic particles (silica particle average particle diameter 1 μm). ), Polystyrene-based organic particles (average particle size 2 μm), and resin composition containing olefin-based wax.

(Resin composition 4 (used in Example 4))
100 parts by mass of resin (polyurethane formed from a mixture of one polyol compound and an aliphatic isocyanate compound), 10 parts by mass of inorganic particles (barium sulfate particles average particle diameter 1 μm), and polystyrene organic particles (average particles) Resin composition containing 2 μm in diameter) and olefinic wax

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

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

(Resin composition 7 (used in Example 7))
A resin composition in which the resin composition of Example 3 does not contain an olefin wax.

(Resin composition 8 (used in Comparative Example 1))
The same material as in Example 1 was used except that an aromatic isocyanate compound different from that in Example 1 was used.

(Resin composition 9 (used in Example 9))
Resin (polyurethane formed from a mixture of two types of polyol compound and aromatic isocyanate compound (the compounding ratio of the two types of polyol compounds is changed from resin composition 1)) and inorganic particles (silica particle average particle diameter 1 μm). ) And polystyrene-based organic particles (average particle size 2 μm).

(Resin composition 10 (used in Example 10))
Resin (polyurethane formed from a mixture of two types of polyol compound and aromatic isocyanate compound (the compounding ratio of the two types of polyol compounds is changed from resin composition 1)) and inorganic particles (silica particle average particle diameter 1 μm). ) And polystyrene-based organic particles (average particle size 2 μm).

[Hardness measured by nanoindentation method in 23 ° C environment]
The hardness was measured using a nanoindenter (“TI950 TriboIndenter” manufactured by HYSITRON) as an apparatus. As the indenter of the nano indenter, a Berkovich indenter (TI-0039) was used. First, in an environment with a relative humidity of 50% and 23 ° C., the indenter is applied to the surface of the surface coating layer of the exterior material for a power storage device (the surface on which the surface coating layer is exposed and parallel to the thickness direction of each layer). The indenter was pushed into the surface coating layer from the surface to a load of 50 μN over 10 seconds, held for 5 seconds in that state, and then unloaded over 10 seconds. The average value of N = 5 measured by shifting the measurement points was taken as the hardness. The results are shown in Table 1. The surface on which the indenter is pushed is a resin portion having an exposed cross section of the surface coating layer obtained by cutting in the thickness direction so as to pass through the central portion of the exterior material for a power storage device. Further, in the measurement of the hardness of the surface coating layer, the portion where the indenter is pushed is a portion (resin portion) in which particles do not exist on the surface of the surface coating layer. The measurement results were rounded to the first decimal place. The organic particles contained in the surface coating layers of Examples 1-10 and Comparative Example 1 are the same, and the surface coating layers of Examples 2 and 10 are measured by pushing an indenter into a portion where the organic particles are present. The hardness was 496.1 MPa. Cutting was performed using a commercially available rotary microtome. The measurement results were rounded to the first decimal place.

[Moldability]
The exterior material for each power storage device was cut into a rectangle having a length (MD) of 90 mm and a width (TD) of 150 mm to prepare a test sample. The MD of the exterior material for the power storage device corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the exterior material for the power storage device corresponds to the TD of the aluminum alloy foil. This test sample is subjected to a rectangular molding mold (female mold, surface is JIS B 0659-1: 2002) having a diameter of 31.6 mm (MD) × 54.5 mm (TD) in an environment of 25 ° C. Book 1 (Reference) The maximum height roughness (nominal value of Rz) specified in Table 2 of the comparative surface roughness standard piece is 3.2 μm. Corner R2.0 mm, ridge line R1.0 mm) and this. Molding dies corresponding to (male mold, the surface of the ridge line is JIS B 0659-1: 2002 Annex 1 (reference) Maximum height roughness specified in Table 2 of the comparative surface roughness standard piece (reference) The nominal value of Rz) is 1.6 μm, and the surface other than the ridgeline is the maximum height roughness specified in Table 2 of JIS B 0659-1: 2002 Annex 1 (Reference) Comparative Surface Roughness Standard Piece. (Nominal value of Rz) is 3.2 μm. Using a corner R2.0 mm, ridge line R1.0 mm), with a pressing pressure (surface pressure) of 0.22 MPa and a molding depth of 5 mm, about 10 test samples. Cold molding (pull-in one-stage molding) was performed. At this time, the test sample was placed on the female mold so that the thermosetting resin layer side was located on the male mold side, and molding was performed. The clearance between the male type and the female type was set to 0.3 mm. For each of the test samples after cold molding, the matte design after molding was evaluated according to the following criteria. The results are shown in Table 1.
A: The matte design was well maintained even after molding, and the surface coating layer was not cracked or peeled off.
B: After molding, the surface coating layer was not cracked or peeled off, but the surface of the surface coating layer was glossy and the matte design was impaired.
C: After molding, the surface of the surface coating layer was glossy and the matte design was impaired, and the surface coating layer was cracked or peeled off.

In the exterior material for a power storage device of Example 1-10, the surface coating layer contains a resin and particles, and the hardness of the outer surface of the surface coating layer measured by the nanoindentation method in an environment of 23 ° C. , 420.4 MPa or less. In the exterior material for the power storage device of Example 1-10, the occurrence of cracking or peeling of the surface coating layer due to molding of the exterior material for the power storage device is suppressed. Further, in Examples 5 and 6 in which the amount of wax added to the surface coating layer was small, the occurrence of cracking and peeling of the surface coating layer was further suppressed, and Examples 7 and 9 did not contain wax in the surface coating layer. In Nos. 10 and 10, the occurrence of cracking and peeling of the surface coating layer was further suppressed.

As described above, the present disclosure provides the inventions of the following aspects.
Item 1. From the outside, it is composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer.
The surface coating layer contains resin and particles, and contains resin and particles.
An exterior material for a power storage device in which the hardness of the resin of the surface coating layer measured by the nanoindentation method with respect to the cross section in the thickness direction of the surface coating layer in an environment of 23 ° C. is 420.4 MPa or less.
Item 2. Item 2. For a power storage device according to Item 1, wherein in a 23 ° C. environment, the hardness of the particles of the surface coating layer measured by the nanoindentation method with respect to the cross section in the thickness direction of the surface coating layer is 300.0 MPa or more. Exterior material.
Item 3. Item 2. The exterior material for a power storage device according to Item 1 or 2, wherein an adhesive layer is provided between the base material layer and the barrier layer.
Item 4. Item 3. The exterior material for a power storage device, wherein the adhesive layer is colored.
Item 5. Item 2. The exterior material for a power storage device according to any one of Items 1 to 4, wherein a colored layer is provided between the base material layer and the barrier layer.
Item 6. A method for manufacturing exterior materials for power storage devices.
A step of obtaining a laminate in which at least a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer are laminated in order from the outside is provided.
The surface coating layer contains resin and particles, and contains resin and particles.
A method for producing an exterior material for a power storage device, wherein the hardness of the resin of the surface coating layer measured by the nanoindentation method is 420.4 MPa or less with respect to the cross section of the surface coating layer in the thickness direction in an environment of 23 ° C. ..
Item 7. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for the power storage device according to any one of Items 1 to 5.

1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Thermosetting resin layer 5 Adhesive layer 6 Surface coating layer 10 Exterior material for power storage devices

Claims

From the outside, it is composed of a laminate having at least a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer.
The surface coating layer contains resin and particles, and contains resin and particles.
An exterior material for a power storage device in which the hardness of the resin of the surface coating layer measured by the nanoindentation method with respect to the cross section in the thickness direction of the surface coating layer in an environment of 23 ° C. is 420.4 MPa or less.
The power storage device according to claim 1, wherein in a 23 ° C. environment, the hardness of the particles of the surface coating layer measured by the nanoindentation method is 300.0 MPa or more with respect to the cross section in the thickness direction of the surface coating layer. Exterior material.
The exterior material for a power storage device according to claim 1 or 2, wherein an adhesive layer is provided between the base material layer and the barrier layer.
The exterior material for a power storage device according to claim 3, wherein the adhesive layer is colored.
The exterior material for a power storage device according to any one of claims 1 to 4, wherein a colored layer is provided between the base material layer and the barrier layer.
A method for manufacturing exterior materials for power storage devices.
A step of obtaining a laminate in which at least a surface coating layer, a base material layer, a barrier layer, and a thermosetting resin layer are laminated in order from the outside is provided.
The surface coating layer contains resin and particles, and contains resin and particles.
A method for producing an exterior material for a power storage device, wherein the hardness of the resin of the surface coating layer measured by the nanoindentation method is 420.4 MPa or less with respect to the cross section of the surface coating layer in the thickness direction in an environment of 23 ° C. ..
A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for the power storage device according to any one of claims 1 to 5.