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

Abstract

To provide an exterior packaging material for a power storage device, in which a matte design due to a surface coating layer containing a filler is prevented from being damaged by heat sealing.SOLUTION: An exterior material for a power storage device is composed of a laminate including, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-fusible resin layer, and the surface coating layer includes a resin and a filler, and the hardness of the outer surface of the surface coating layer measured by a nanoindentation method in a 190°C environment is 14.5 MPa or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to an exterior material for an electricity storage device, a manufacturing method thereof, and an electricity storage device. [Background technology]

[0002] Conventionally, various types of electricity storage devices have been developed, and in all electricity storage devices, exterior materials are essential components for sealing electricity storage device elements such as electrodes, electrolytes, etc. Conventionally, metallic exterior materials have been widely used as exterior materials for electricity storage devices.

[0003] Meanwhile, in recent years, various shapes as well as thinner and lighter weight are required for electricity storage devices along with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc. However, the metallic exterior materials for electricity storage devices that have been widely used in the past have the drawbacks of being difficult to keep up with the diversification of shapes and also having limitations in terms of weight reduction.

[0004] In recent years, a film-like laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated in this order has been proposed as an exterior material for an electricity storage device that can be easily processed into a variety of shapes and can be made thinner and lighter (see, for example, Patent Document 1).

[0005] In such an exterior material for an electricity storage device, a recess is generally formed by cold forming, and electricity storage device elements such as electrodes and an electrolyte are placed in the space formed by the recess, and the heat-fusible resin layer is heat-fused (heat sealed) to obtain an electricity storage device in which the electricity storage device elements are housed inside the exterior material for an electricity storage device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-287971 A Summary of the Invention [Problem to be solved by the invention]

[0007] In an exterior material for an electricity storage device composed of a film-like laminate, a surface coating layer containing a filler may be provided on the outside of a base layer in order to give the outer surface a matte design.

[0008] However, when sealing an electricity storage device element using an exterior material for an electricity storage device, if a heat-sealing member (e.g., a metal heat seal bar) is used to apply heat and pressure from above the surface coating layer to heat-seal the heat-sealable resin layer, the uneven surface of the surface coating layer formed by the filler is crushed, resulting in a problem that the matte design of the heat-sealed portion is compromised.

[0009] Under these circumstances, a main object of the present disclosure is to provide an exterior material for an electricity storage device in which the matte design provided by a surface coating layer containing a filler is prevented from being damaged by heat sealing. [Means for solving the problem]

[0010] The inventors of the present disclosure have conducted intensive studies to solve the above-mentioned problems. As a result, they have found that an exterior material for an electricity storage device, which is composed of a laminate including, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, the surface coating layer includes a resin and a filler, and the hardness of the outer surface of the surface coating layer measured by a nanoindentation method in a 190°C environment is 14.5 MPa or more, is suppressed from impairing the matte design provided by the surface coating layer including the filler due to heat sealing.

[0011] The present disclosure has been completed based on these findings and through further investigations. That is, the present disclosure provides the invention of the following aspects. The laminate includes, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, The surface coating layer includes a resin and a filler, An exterior material for an electricity storage device, wherein the hardness of the outer surface of the surface coating layer, as measured by a nanoindentation method in an environment of 190°C, is 14.5 MPa or more. Effect of the Invention

[0012] According to the present disclosure, it is possible to provide an exterior material for an electricity storage device in which the matte design provided by a surface coating layer containing a filler is prevented from being damaged by heat sealing. In addition, according to the present disclosure, it is also possible to provide a manufacturing method for the exterior material for an electricity storage device, and an electricity storage device using the exterior material for an electricity storage device. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. [Diagram 2] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. [Diagram 3] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. [Figure 4] FIG. 1 is a schematic diagram for explaining a method for evaluating a matte finish design after heat sealing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The exterior material for an electricity storage device of the present disclosure is composed of a laminate including, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, the surface coating layer containing a resin and a filler, and is characterized in that the hardness of the outer surface of the surface coating layer measured by a nanoindentation method in an environment of 190° C. is 14.5 MPa or more. By having this configuration, the exterior material for an electricity storage device of the present disclosure is suppressed from impairing the matte design provided by the surface coating layer containing a filler due to heat sealing.

[0015] The exterior material for an electricity storage device according to the present disclosure will be described in detail below. In this specification, the numerical range indicated by "to" means "not less than" or "not more than." For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less.

[0016] 1.Layer structure and physical properties of exterior materials for energy storage devices The exterior material 10 for an electricity storage device according to the present disclosure is composed of a laminate including, in order from the outside, a surface coating layer 6, a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4, as shown in, for example, FIG. 1 to FIG. 3. In the exterior material 10 for an electricity storage device, the surface coating layer 6 is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. When assembling an electricity storage device using the exterior material 10 for an electricity storage device and an electricity storage device element, the heat-sealable resin layers 4 of the exterior material 10 for an electricity storage device are placed opposite each other, and the electricity storage device element is accommodated in a space formed by heat-sealing the periphery. In the laminate constituting the exterior material 10 for an electricity storage device according to the present disclosure, the barrier layer 3 is used as a reference, and the heat-sealable resin layer 4 side is the inner side relative to the barrier layer 3, and the surface coating layer 6 side is the outer side relative to the barrier layer 3.

[0017] As shown in Figures 2 and 3, for example, the exterior material 10 for an electricity storage device may have an adhesive layer 2 between the base material layer 1 and the barrier layer 3, if necessary, for the purpose of increasing the adhesion between these layers. Although not shown, a colored layer may be provided between the base material layer 1 and the barrier layer 3. As shown in Figure 3, for example, the exterior material 10 for an electricity storage device may have an adhesive layer 5 between the barrier layer 3 and the heat-sealable resin layer 4, if necessary, for the purpose of increasing the adhesion between these layers.

[0018] The thickness of the laminate constituting the electricity storage device exterior material 10 is not particularly limited, but the upper limit, from the viewpoints of cost reduction, energy density improvement, and the like, is preferably about 180 μm or less, about 160 μm or less, about 155 μm or less, about 140 μm or less, about 130 μm or less, and about 120 μm or less. The lower limit, from the viewpoint of maintaining the function of the electricity storage device exterior material to protect the electricity storage device elements, is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, and about 80 μm or more. Preferred ranges include, for example, about 35 to 180 μm, 35 to 1 Examples of the thickness include about 60 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, about 45 to 155 μm, about 45 to 140 μm, about 45 to 130 μm, about 45 to 120 μm, about 60 to 180 μm, about 60 to 160 μm, about 60 to 155 μm, about 60 to 140 μm, about 60 to 130 μm, about 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, and about 80 to 120 μm. Among these, about 80 to 130 μm is particularly preferable.

[0019] In the exterior material 10 for an electricity storage device according to the present disclosure, the hardness of the outer surface of the surface coating layer 6 is 14.5 MPa or more as measured by a nanoindentation method in an environment of 190° C. In the exterior material 10 for an electricity storage device, the surface coating layer 6 has the above-mentioned hardness in an extremely high-temperature environment of 190° C., and therefore the matte design provided by the surface coating layer 6 containing a filler is prevented from being damaged by heat sealing.

[0020] The hardness measured by the nanoindentation method in a 190°C environment may be 14.5 MPa or more, but from the viewpoint of more effectively preventing the matte design from being damaged by heat sealing (hereinafter, sometimes referred to as the viewpoint of the matte design), it is preferably about 18 MPa or more, and also preferably about 150 MPa or less, more preferably about 120 MPa or less, and preferable ranges include about 15 to 150 MPa, about 15 to 120 MPa, about 18 to 150 MPa, and about 18 to 120 MPa. Among these, about 18 to 120 MPa is particularly preferable. The hardness measured by the nanoindentation method in a 190°C environment is measured as follows.

[0021] [Hardness measured by nanoindentation method in 190℃ environment] The hardness is measured using a nanoindenter (for example, HYSITRON's "TI950 TriboIndenter"). A Berkovich indenter (for example, TI-0064) is used as the indenter of the nanoindenter. First, in a relative humidity of 50% and a temperature of 190°C, the indenter is applied to the surface of the surface coating layer of the exterior material for a power storage device (the surface where the measurement target is exposed and perpendicular to the thickness direction of each layer) from a direction parallel to the thickness direction, and the indenter is pressed into the surface coating layer from the surface to a load of 25 μN over 10 seconds, and the state is maintained for 15 seconds, and then the load is removed over 10 seconds. The average value of N=5 measured by shifting the measurement point is taken as the hardness. The surface into which the indenter is pressed is the part exposed on the surface of the exterior material for a power storage device. The sample is fixed using a commercially available instant adhesive. In the cross-sectional structures of the exterior materials for electricity storage devices according to the present disclosure in Figs. 1 to 3, the up-down direction corresponds to the thickness direction of each layer.

[0022] The hardness measured by nanoindentation in a 190°C environment can be adjusted by the composition (type and content of resin) of the resin composition forming the surface coating layer 6, the curing conditions, the molecular weight, the number of functional groups, the crosslinking density, the bulkiness of the substituents, etc.

[0023] In addition, from the viewpoint of achieving the above-mentioned matte design and further improving formability at room temperature, the exterior packaging material 10 for an electricity storage device according to the present disclosure has a resin hardness of the surface coating layer 6, as measured by a nanoindentation method in a cross section in the thickness direction of the surface coating layer 6 in a 23° C. environment, of preferably about 420.4 MPa or less, more preferably about 350.4 MPa or less, and even more preferably about 310.4 MPa or less, and also preferably about 25.5 MPa or more, more preferably about 50.0 MPa or more, and even more preferably about 100.0 MPa or more. More preferably, it is about 150.0 MPa or more, and preferred ranges include about 22.5 to 420.4 MPa, about 22.5 to 350.4 MPa, about 22.5 to 310.4 MPa, about 50.0 to 420.4 MPa, about 50.0 to 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, 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 preferred. In the present invention, excellent formability means, more specifically, that the matte design of the surface coating layer is prevented from being damaged by molding the exterior material 10 for an electricity storage device, and that cracks and peeling of the surface coating layer due to room temperature molding are prevented. The hardness measured by the nanoindentation method in a 23°C environment is measured as follows.

[0024] [Hardness measured by nanoindentation method at 23℃] The hardness is measured using a nanoindenter (for example, HYSITRON's "TI950 TriboIndenter"). A Berkovich indenter (for example, TI-0039) is used as the indenter of the nanoindenter. First, in a relative humidity of 50% and a temperature of 23°C, the indenter is applied to the surface of the surface coating layer of the exterior material for an electric storage device (the surface where the surface coating layer is exposed, and the surface is parallel to the thickness direction of each layer (see the thickness direction W in Figures 1 to 3)) from a direction perpendicular to the thickness direction, and the indenter is pressed into the surface coating layer from the surface to a load of 50 μN over 10 seconds, and the state is maintained for 5 seconds, and then the load is removed over 10 seconds. The average value of N=5 measured by shifting the measurement point is taken as the hardness. The surface into which the indenter is pressed is the resin part where the cross section of the surface coating layer (cross section in the thickness direction of the surface coating layer) obtained by cutting the exterior material for an electric storage device in the thickness direction so as to pass through the center (which may be near the center) is exposed. Sectioning is performed using a commercially available rotary microtome.

[0025] The hardness measured by nanoindentation in a 23°C environment can be adjusted by the composition (resin type, content) of the resin composition forming the surface coating layer 6, the curing conditions, the molecular weight, the number of functional groups, the crosslinking density, the bulkiness of the substituents, etc.

[0026] In addition, from the viewpoint of the above-mentioned matte design, in the exterior material 10 for an electricity storage device according to the present disclosure, the arithmetic mean roughness Ra 1is preferably about 0.30 μm or more, more preferably about 0.40 μm or more, and even more preferably 0.50 or more, and is preferably about 0.90 μm or less, more preferably about 0.80 μm or less, and even more preferably about 0.70 μm or less, and preferred ranges include about 0.30 to 0.90 μm, about 0.30 to 0.80 μm, about 0.30 to 0.70 μm, about 0.40 to 0.90 μm, about 0.40 to 0.80 μm, about 0.40 to 0.70 μm, about 0.50 to 0.90 μm, about 0.50 to 0.80 μm, and about 0.50 to 0.70 μm. Among these, about 0.50 to 0.70 μm is particularly preferred. In addition, the arithmetic average roughness Ra of the outer surface of the surface coating layer 6 after the outer surface of the surface coating layer 6 was heated and pressed using a stainless steel plate under conditions of a temperature of 190° C., a surface pressure of 0.5 MPa, and a time of 6 seconds was 2 The arithmetic mean roughness Ra of the outer surface of the surface coating layer 6 before the outer surface of the surface coating layer is heated and pressed 1 Ratio to Ra 2 / Ra 1 However, the ratio Ra is preferably 0.7 or more. 2 / Ra 1 There is no particular upper limit to the value, but examples of the upper limit include 1.0 and 0.95.

[0027] 2. Each layer that forms the exterior material for electricity storage devices [Surface coating layer 6] The exterior material 10 for an electricity storage device according to 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 an electricity storage device. The surface coating layer 6 is a layer located as the outermost layer of the exterior material 10 for an electricity storage device when an electricity storage device is assembled using the exterior material 10 for an electricity storage device.

[0028] The surface coating layer 6 contains a resin and a filler. Examples of the filler include inorganic fillers and organic fillers. The filler contained in the surface coating layer 6 may be one type or two or more types. It is also preferable to use an inorganic filler and an organic filler in combination. The shape of the filler is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, and scaly shapes.

[0029] The average particle diameter of the filler is not particularly limited, but may be, for example, about 0.01 to 5 μm from the viewpoint of making the exterior material 10 for an electricity storage device have a matte design. The average particle diameter of the filler is the median diameter measured by a laser diffraction / scattering type particle size distribution measuring device. The average particle diameter of the filler is preferably equal to or smaller than the thickness of the surface coating layer 6.

[0030] The inorganic filler is not particularly limited as long as it can give the surface coating layer 6 a matte finish, and examples thereof include particles of silica, talc, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, gold, aluminum, copper, nickel, etc. Among these, silica particles are particularly preferred.

[0031] The organic filler is not particularly limited as long as it can give the surface coating layer 6 a matte finish, and examples of the organic filler include particles of nylon, polyacrylate, polystyrene, polyethylene, benzoguanamine, or crosslinked products thereof.

[0032] In the measurement of the above-mentioned [hardness measured by nanoindentation in a 23°C environment], the surface into which the indenter is pressed is a location where the organic filler is present and the cross section of the surface coating layer is exposed, obtained by cutting the exterior material for an electricity storage device in the thickness direction through the center (which may be near the center), and the hardness of the organic filler contained in the surface coating layer 6 can also be measured. From the viewpoint of the matte design and moldability, the hardness of the organic filler measured in this manner is preferably about 300.0 MPa or more, more preferably about 400.0 MPa or more, and also preferably about 1500.4 MPa or less, more preferably about 1000.4 MPa or less, and even more preferably about 600.4 MPa or less. Preferred ranges include about 300.0 to 1500.4 MPa, about 300.0 to 1000.4 MPa, about 300.0 to 600.4 MPa, about 400.0 to 1500.4 MPa, about 400.0 to 1000.4 MPa, and about 400.0 to 600.4 MPa. Among these, about 400.0 to 600.4 MPa is particularly preferred.

[0033] The content of the filler contained in the surface coating layer 6 is not particularly limited, as long as the hardness measured by the nanoindentation method in a 190°C environment is 14.5 MPa or more, but is preferably about 3 parts by mass or more, more preferably about 10 parts by mass or more, and is also preferably about 30 parts by mass or less, more preferably about 20 parts by mass or less, relative to 100 parts by mass of the resin in the resin composition that forms the surface coating layer 6. 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.

[0034] The resin contained in the resin composition forming the surface coating layer 6 is preferably a curable resin, but is not particularly limited as long as the hardness measured by the nanoindentation method in an environment of 190° C. is 14.5 MPa or more. In other words, the surface coating layer 6 is preferably composed of a cured product of a resin composition containing a curable resin and a filler.

[0035] 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 two-component curing resins include two-component curing polyurethane, two-component curing polyester, and two-component curing epoxy resin. Among these, two-component curing polyurethane is preferred.

[0036] Examples of two-component curing polyurethane include polyurethanes containing a base material containing a polyol compound and a curing agent containing an isocyanate compound. Preferably, two-component curing polyurethanes are used in which a polyol such as polyester polyol, polyether polyol, and acrylic polyol is used as a base material, and an aromatic or aliphatic polyisocyanate is used as a curing agent. In addition, it is preferable to use a polyester polyol having a hydroxyl group on the side chain in addition to the terminal hydroxyl group of the repeating unit as the polyol compound. Examples of curing agents include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). Further, polyfunctional isocyanate modified products of one or more of these diisocyanates can be used. Furthermore, a polymer (e.g., a trimer) can also be used as the polyisocyanate compound. Examples of such a polymer include an adduct, a biuret, and a nurate. The aliphatic isocyanate compound refers to an isocyanate having an aliphatic group and no aromatic ring, the alicyclic isocyanate compound refers to an isocyanate having an alicyclic hydrocarbon group, and the aromatic isocyanate compound refers to an isocyanate having an aromatic ring.

[0037] In the resin composition forming the surface coating layer 6, when the resin is a polyurethane containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound, for example, the hardness measured by the nanoindentation method in a 190°C environment and a 23°C environment can be adjusted by adjusting the ratio of the base agent to the curing agent.

[0038] At least one of the surface and the interior of the surface coating layer 6 may further contain additives such as lubricants, colorants, antiblocking agents, flame retardants, antioxidants, tackifiers, and antistatic agents, as described below, depending on the functionality to be provided to the surface coating layer 6 and its surface.

[0039] When the surface coating layer 6 contains a colorant, known colorants such as pigments and dyes can be used as the colorant. In addition, only one type of colorant may be used, or two or more types may be mixed and used. Specific examples of the colorant contained in the surface coating layer 6 include the same as those exemplified in the [Adhesive layer 2] section. In addition, the preferred content of the colorant contained in the surface coating layer 6 is also the same as the content described in the [Adhesive layer 2] section.

[0040] The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method for applying a resin composition for forming the surface coating layer 6. When an additive is blended into the surface coating layer 6, a resin mixed with the additive may be applied.

[0041] From the viewpoint of the above-mentioned matte design, the thickness of the surface coating layer 6 is preferably 0.5 μm or more, more preferably 1 μm or more, and 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.

[0042] In the present disclosure, from the viewpoint of improving the moldability of the exterior material for a power storage device, it is preferable that a lubricant is present on the surface of the surface coating layer 6. The lubricant is not particularly limited, but is preferably an amide-based lubricant. Specific examples of amide-based lubricants include, for example, 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 saturated fatty acid amides include lauric acid amides, palmitic acid amides, stearic acid amides, behenic acid amides, and hydroxystearic acid amides. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of substituted amides include N-oleyl palmitic acid amides, N-stearyl stearic acid amides, N-stearyl oleic acid amides, N-oleyl stearic acid amides, and N-stearyl erucic acid amides. Specific examples of methylol amides include methylol stearic acid amides. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N,N'-distearylisophthalic acid amide, etc. The lubricant may be used alone or in combination of two or more kinds.

[0043] When a lubricant is present on the surface of the surface coating layer 6, the amount of the lubricant is not particularly limited, but is preferably about 3 mg / m 2 More preferably, 4 to 15 mg / m 2 about 5 to 14 mg / m 2 The degree of

[0044] The lubricant present on the surface of the surface coating layer 6 may be a lubricant that is exuded from the surface coating layer 6, or a lubricant that is applied to the surface of the surface coating layer 6.

[0045] [Base material layer 1] In the present disclosure, the substrate layer 1 is a layer provided for the purpose of, for example, exhibiting the function as a substrate of the exterior material for an electricity storage device. The substrate layer 1 is located between the surface coating layer 6 and the barrier layer 3 of the exterior material for an electricity storage device 10. In addition, in the case where the adhesive layer 2 is provided, the substrate layer 1 is located between the surface coating layer 6 and the adhesive layer 2.

[0046] The material forming the base layer 1 is not particularly limited as long as it has the function of a base, that is, at least insulating properties. The base layer 1 can be formed using, for example, a resin, and the resin may contain additives described later.

[0047] When the base layer 1 is made of a resin, the base layer 1 may be, for example, a resin film made of a resin, or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially stretched films and biaxially stretched films, and biaxially stretched films are preferred. Examples of stretching methods for forming biaxially stretched films include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying a resin include roll coating, gravure coating, and extrusion coating.

[0048] Examples of the resin forming the base layer 1 include polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, as well as modified versions of these resins. The resin forming the base layer 1 may be a copolymer of these resins or a modified version of the copolymer. Furthermore, it may be a mixture of these resins.

[0049] Of these, preferred examples of the resin forming the base layer 1 include polyester and polyamide.

[0050] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyesters. Examples of copolymerized polyesters include copolymerized polyesters in which ethylene terephthalate is the main repeating unit. Specific examples of polyesters include copolymerized polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), and polyethylene (terephthalate / decane dicarboxylate). These polyesters may be used alone or in combination of two or more.

[0051] Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid, and T represents terephthalic acid) that contain structural units derived from terephthalic acid and / or isophthalic acid, and polyamides containing aromatic compounds such as polyamide MXD6 (polymetaxylylene adipamide); alicyclic polyamides such as polyamide PACM6 (polybis(4-aminocyclohexyl)methane adipamide); polyamides copolymerized with a lactam component or an isocyanate component such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers that are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and polyamides such as copolymers of these copolymers. These polyamides may be used alone or in combination of two or more.

[0052] The base layer 1 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, preferably includes at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, more preferably includes at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film, and even more preferably includes at least one of a biaxially oriented polyethylene terephthalate film, a biaxially oriented polybutylene terephthalate film, a biaxially oriented nylon film, and a biaxially oriented polypropylene film.

[0053] The base layer 1 may be a single layer, or may be composed of two or more layers. When the base layer 1 is composed of two or more layers, the base layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or may be a laminate of resin films in which resins are co-extruded to form two or more layers. In addition, a laminate of resin films in which resins are co-extruded to form two or more layers may be used as the base layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base layer 1.

[0054] In the base layer 1, specific examples of the laminate of two or more resin films include a laminate of a polyester film and a nylon film, a laminate of two or more nylon films, and a laminate of two or more polyester films, and preferably a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, and a laminate of two or more stretched polyester films. For example, when the base layer 1 is a laminate of two resin films, a laminate of a polyester resin film and a polyester resin film, a laminate of a polyamide resin film and a polyamide resin film, or a laminate of a polyester resin film and a polyamide resin film is preferred, 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 preferred. In addition, when the base layer 1 is a laminate of two or more resin films, it is preferable that the polyester resin film is located in the outermost layer of the base layer 1, because the polyester resin is less likely to discolor when, for example, an electrolyte is attached to the surface.

[0055] When the base layer 1 is a laminate of two or more resin films, the two or more resin films may be laminated via an adhesive. Preferred adhesives include the same adhesives as those exemplified in the adhesive layer 2 described later. The method for laminating two or more resin films is not particularly limited, and known methods can be adopted, such as dry lamination, sandwich lamination, extrusion lamination, and thermal lamination, and preferably dry lamination. When laminating by the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive is, for example, about 2 to 5 μm. Also, an anchor coat layer may be formed on the resin film and laminated. The anchor coat layer may be the same adhesive as that exemplified in the adhesive layer 2 described later. In this case, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

[0056] Furthermore, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present on at least one of the surface and the interior of the base layer 1. The additives may be used alone or in combination of two or more.

[0057] The thickness of the base layer 1 is not particularly limited as long as it functions as a base, and examples of the thickness include about 3 to 50 μm, about 3 to 35 μm, and about 3 to 25 μm. When the base layer 1 is a laminate of two or more resin films, the thickness of each of the resin films constituting each layer is preferably about 2 to 25 μm.

[0058] [Adhesive layer 2] In the exterior material for an electricity storage device of the present disclosure, the adhesive layer 2 is a layer that is provided between the base layer 1 and the barrier layer 3 as necessary for the purpose of increasing the adhesion between them.

[0059] The adhesive layer 2 is formed of an adhesive capable of bonding the base material layer 1 and the barrier layer 3. The adhesive used to form the adhesive layer 2 is not limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, etc. Also, it may be a two-component curing adhesive (two-component adhesive), a one-component curing adhesive (one-component adhesive), or a resin that does not involve a curing reaction. Also, the adhesive layer 2 may be a single layer or multiple layers.

[0060] Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymerized polyamides; polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, polyurethane adhesives are preferred. In addition, the adhesive strength of these adhesive component resins can be increased by using an appropriate curing agent in combination. The curing agent is selected from polyisocyanates, multifunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, and the like, depending on the functional groups of the adhesive components.

[0061] Examples of polyurethane adhesives include polyurethane adhesives containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferably, a two-liquid curing type polyurethane adhesive is used in which a polyol such as polyester polyol, polyether polyol, and acrylic polyol is used as the base agent, and an aromatic or aliphatic polyisocyanate is used as the curing agent. In addition, it is preferable to use a polyester polyol having a hydroxyl group on the side chain in addition to the terminal hydroxyl group of the repeating unit as the polyol compound. Examples of curing agents include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of isocyanate compounds include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and naphthalene diisocyanate (NDI). Further, polyfunctional isocyanate modified bodies of one or more of these diisocyanates can be used. Furthermore, a polymer (e.g., a trimer) can also be used as the polyisocyanate compound. Examples of such polymers include adducts, biurets, and nurates. The adhesive layer 2 is formed from a polyurethane adhesive, which gives the exterior material for an electricity storage device excellent electrolyte resistance, and prevents the base layer 1 from peeling off even if the electrolyte adheres to the side surface.

[0062] In addition, the adhesive layer 2 is allowed to contain other components as long as they do not impair adhesion, and may contain a colorant, a thermoplastic elastomer, a tackifier, a filler, etc. By containing a colorant in the adhesive layer 2, the exterior material for a power storage device can be colored. As the colorant, known colorants such as pigments and dyes can be used. In addition, only one type of colorant may be used, or two or more types may be mixed and used.

[0063] The type of pigment is not particularly limited as long as it does not impair the adhesiveness of the adhesive layer 2. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments, while examples of inorganic pigments 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, fish scale foil, and the like.

[0064] Among colorants, carbon black is preferred in order to give the exterior material for an electricity storage device a black appearance, for example.

[0065] The average particle size of the pigment is not particularly limited and may be, for example, about 0.05 to 5 μm, and preferably about 0.08 to 2 μm. The average particle size of the pigment is the median size measured by a laser diffraction / scattering type particle size distribution measuring device.

[0066] The content of the pigment in the adhesive layer 2 is not particularly limited as long as the exterior material for an electricity storage device is colored, and is, for example, about 5 to 60 mass %, preferably 10 to 40 mass %.

[0067] The thickness of the adhesive layer 2 is not particularly limited as long as it can bond the base layer 1 and the barrier layer 3, but the lower limit is, for example, about 1 μm or more, about 2 μm or more, and the upper limit is about 10 μm or less, about 5 μm or less, and preferred ranges are about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[0068] [Colored layer] The colored layer is a layer that is provided between the base material layer 1 and the barrier layer 3 as necessary (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, or between the adhesive layer 2 and the barrier layer 3. Also, a colored layer may be provided on the outside of the base material layer 1. By providing a colored layer, the exterior material for an electricity storage device can be colored.

[0069] The colored layer can be formed, for example, by applying an ink containing a colorant to the surface of the base layer 1 or the surface of the barrier layer 3. As the colorant, known substances such as pigments and dyes can be used. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[0070] Specific examples of the colorant contained in the colored layer include the same as those exemplified in the section [Adhesive layer 2].

[0071] [Barrier layer 3] In the packaging material for an electricity storage device, the barrier layer 3 is a layer that at least prevents the penetration of moisture.

[0072] Examples of the barrier layer 3 include metal foils, vapor-deposited films, and resin layers having barrier properties. Examples of the vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Examples of the resin layer include fluorine-containing resins such as polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of fluoroalkyl units, and ethylene-vinyl alcohol copolymers. Examples of the barrier layer 3 include resin films having at least one of these vapor-deposited films and resin layers. The barrier layer 3 may be provided in a plurality of layers. The barrier layer 3 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, it is preferable to include at least one of aluminum alloy foil and stainless steel foil.

[0073] From the viewpoint of suppressing the occurrence of pinholes and cracks during molding of the exterior material for a power storage device, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of more effectively suppressing the occurrence of pinholes and cracks during molding, the aluminum alloy foil is preferably an iron-containing aluminum alloy foil. In the iron-containing aluminum alloy foil (100 mass%), the iron content is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%. By making the iron content 0.1 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. By making the iron content 9.0 mass% or less, it is possible to obtain an exterior material for a power storage device with better flexibility. Examples of the soft aluminum alloy foil include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may be added as necessary. Softening can be performed by annealing or the like.

[0074] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. From the viewpoint of suppressing the occurrence of pinholes and cracks during the molding of the exterior material for the power storage device, the stainless steel foil is preferably made of austenitic stainless steel.

[0075] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferred.

[0076] When the barrier layer 3 is a metal foil, it is sufficient that the barrier layer 3 has a thickness that at least functions as a barrier layer that prevents the intrusion of moisture, and the thickness 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, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less, and preferably about 10 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more, with the thickness being preferably in the range of 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, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm, and among these, about 25 to 40 μm is particularly preferred. When the barrier layer 3 is made of an aluminum alloy foil, the above-mentioned range is particularly preferred. In particular, when the barrier layer 3 is composed of a stainless steel foil, the upper limit of the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less, and the lower limit is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred thickness ranges include 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, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0077] In addition, when the barrier layer 3 is a metal foil, it is preferable to provide a corrosion-resistant film at least on the surface opposite to the base layer in order to prevent dissolution and corrosion. The barrier layer 3 may have a corrosion-resistant film on both sides. Here, the corrosion-resistant film refers to a thin film that is provided with corrosion resistance by performing, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment such as nickel or chromium, or corrosion prevention treatment by applying a coating agent on the surface of the barrier layer. As a treatment for forming a corrosion-resistant film, one type may be performed, or two or more types may be combined. In addition to one layer, multiple layers can be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved by a treatment agent to form a metal compound having excellent corrosion resistance. Note that these treatments may be included in the definition of chemical conversion treatment. In addition, when the barrier layer 3 has a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

[0078] The corrosion-resistant coating prevents delamination between a barrier layer (e.g., an aluminum alloy foil) and a base layer during molding of an exterior material for an electricity storage device, prevents dissolution and corrosion of the barrier layer surface due to hydrogen fluoride produced by a reaction between an electrolyte and moisture, and in particular prevents dissolution and corrosion of aluminum oxide present on the barrier layer surface when the barrier layer is an aluminum alloy foil, and also improves the adhesion (wettability) of the barrier layer surface, thereby preventing delamination between the base layer and the barrier layer during heat sealing and between the base layer and the barrier layer during molding.

[0079] Various corrosion-resistant films formed by chemical conversion treatments are known, and mainly include corrosion-resistant films containing at least one of phosphates, chromates, fluorides, triazine thiol compounds, and rare earth oxides. Examples of chemical conversion treatments using phosphates and chromates include chromate chromate treatment, phosphoric acid chromate treatment, phosphoric acid-chromate treatment, and chromate treatment. Examples of chromium compounds used in these treatments include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromate acetyl acetate, chromium chloride, and potassium chromium sulfate. Examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid. Examples of chromate treatments include etching chromate treatment, electrolytic chromate treatment, and coating-type chromate treatment, and coating-type chromate treatment is preferred. In this coating type chromate treatment, at least the inner layer side of the barrier layer (e.g., aluminum alloy foil) is first degreased by a known treatment method such as an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or an acid activation method, and then the degreased surface is coated with a treatment liquid mainly composed of a metal phosphate such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, or Zn (zinc) phosphate, or a mixture of these metal salts, or a treatment liquid mainly composed of a nonmetallic phosphate and a mixture of these nonmetallic salts, or a treatment liquid consisting of a mixture of these with a synthetic resin, or the like, by a known coating method such as a roll coating method, a gravure printing method, or a dipping method, and then dried. As the treatment liquid, various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents can be used, and water is preferred. Examples of the resin component used here include polymers such as phenolic resins and acrylic resins, and chromate treatment using an aminated phenol polymer having repeating units represented by the following general formulas (1) to (4). 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 types.The acrylic resin is preferably polyacrylic acid, acrylic acid methacrylic acid ester copolymer, acrylic acid maleic acid copolymer, acrylic acid styrene copolymer, or a derivative thereof such as sodium salt, ammonium salt, or amine salt. In particular, a derivative of polyacrylic acid such as an ammonium salt, sodium salt, or amine salt of polyacrylic acid is preferable. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. The acrylic resin is also preferably a copolymer of acrylic acid and dicarboxylic acid or dicarboxylic acid anhydride, and is also preferably an ammonium salt, sodium salt, or amine salt of a copolymer of acrylic acid and dicarboxylic acid or dicarboxylic acid anhydride. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] 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. 1 and R 2 In the general formulae (1) to (4), X and R each independently represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. 1 and R 2Examples of the alkyl group represented by the formula (I) include linear or branched alkyl groups having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. 1 and R 2 Examples of the hydroxyalkyl group represented by the formula (1) to (4) include linear or branched alkyl groups having 1 to 4 carbon atoms substituted with one hydroxy group, such as a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, and a 4-hydroxybutyl group. 1 and R 2 The alkyl group and the hydroxyalkyl group represented by the following formulae may be the same or different. In the general formulae (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 units represented by the general formulae (1) to (4) is preferably about 500 to 1,000,000, for example, and more preferably about 1,000 to 20,000. The aminated phenol polymer can be prepared, for example, by polycondensing a phenol compound or a naphthol compound with formaldehyde to produce a polymer consisting of the repeating units represented by the above general formula (1) or (3), and then polycondensing the polymer with formaldehyde and an amine (R 1 R 2 NH) to the functional group (-CH 2 NR 1 R 2 The aminated phenol polymers can be used alone or in combination of two or more.

[0085] Another example of the corrosion-resistant film is a thin film 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 coating agent may further contain phosphoric acid or a phosphate, and a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol has rare earth element oxide fine particles (for example, particles with an average particle size of 100 nm or less) dispersed in a liquid dispersion medium. Examples of rare earth element oxides include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide, and cerium oxide is preferred from the viewpoint of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant film can be used alone or in combination of two or more. Examples of the liquid dispersion medium for the rare earth element oxide sol include various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents, and water is preferred. As the cationic polymer, for example, polyethyleneimine, an ionic polymer complex consisting of a polymer having polyethyleneimine and a carboxylic acid, a primary amine grafted acrylic resin in which a primary amine is graft-polymerized to an acrylic main skeleton, polyallylamine or its derivative, aminated phenol, etc. are preferable. In addition, as the anionic polymer, poly(meth)acrylic acid or its salt, or a copolymer mainly composed of (meth)acrylic acid or its salt, is preferable. In addition, it is preferable that the crosslinking agent is at least one selected from the group consisting of a compound having any one of a functional group of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent. In addition, it is preferable that the phosphoric acid or the phosphoric acid salt is a condensed phosphoric acid or a condensed phosphate salt.

[0086] One example of a corrosion-resistant coating is one formed by applying a solution of fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, or barium sulfate dispersed in phosphoric acid to the surface of a barrier layer and baking the coating at 150°C or higher.

[0087] If necessary, the corrosion-resistant coating may have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated. Examples of the cationic polymer and anionic polymer include those mentioned above.

[0088] The composition of the corrosion-resistant film can be analyzed by, for example, time-of-flight secondary ion mass spectrometry.

[0089] 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. For example, in the case of coating-type chromate treatment, the amount of the corrosion-resistant film formed on the surface of the barrier layer 3 is preferably 1 mm. 2 It is desirable that the chromate compound is contained in an amount, calculated as chromium, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, the phosphorus compound is contained in an amount, calculated as phosphorus, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, and the aminated phenol polymer is contained in an amount, calculated as phosphorus, of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, per unit weight of the ink.

[0090] The thickness of the corrosion-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 nm to 100 nm, and even more preferably about 1 nm to 50 nm, from the viewpoint of the cohesive strength of the film and the adhesive strength with the barrier layer and the heat-sealable resin layer. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope, or a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy. Analysis of the composition of the corrosion-resistant film using time-of-flight secondary ion mass spectrometry can reveal that, for example, secondary ions consisting of Ce, P, and O (e.g., Ce 2 PO 4 + , CePO 4 - At least one of the above) and secondary ions consisting of, for example, Cr, P and O (e.g., CrPO 2 + , CrPO 4 - Peaks derived from at least one of the above are detected.

[0091] The chemical conversion treatment is carried out by applying a solution containing a compound used for forming a corrosion-resistant film 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 heating the barrier layer so that the temperature of the barrier layer becomes about 70 to 200°C. In addition, before applying the chemical conversion treatment 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. By carrying out the degreasing treatment in this manner, it becomes possible to carry out the chemical conversion treatment of the surface of the barrier layer more efficiently. In addition, 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 not only degrease the metal foil but also form a fluoride of the metal that is in a passive state, and in such a case, only the degreasing treatment may be carried out.

[0092] [Thermofusible resin layer 4] In the exterior packaging material for an electricity storage device of the present disclosure, the heat-sealable resin layer 4 corresponds to the innermost layer and is a layer (sealant layer) that exhibits the function of sealing the electricity storage device elements by heat-sealing the heat-sealable resin layers to each other when the electricity storage device is assembled.

[0093] The resin constituting the heat-sealable resin layer 4 is not particularly limited as long as it is heat-sealable, but is preferably a resin containing a polyolefin skeleton, such as polyolefin or acid-modified polyolefin. The inclusion of a polyolefin skeleton in the resin constituting the heat-sealable resin layer 4 can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like. Furthermore, when the resin constituting the heat-sealable resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wave number of 1760 cm. -1 Nearby and wave number 1780cm -1A peak derived from maleic anhydride is detected near the peak. When the thermally adhesive resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected by infrared spectroscopy. However, if the degree of acid modification is low, the peak becomes small and may not be detected. In that case, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0094] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. Among these, polypropylene is preferred. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. These polyolefin resins may be used alone or in combination of two or more.

[0095] The polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefins constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of the cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkenes are preferred, and norbornene is more preferred.

[0096] The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. The polyolefin to be modified with an acid may be 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. The acid component used for the acid modification may be, for example, a carboxylic acid or an anhydride such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, or itaconic anhydride.

[0097] 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 by replacing it with an acid component, or by block-polymerizing or graft-polymerizing an acid component to the cyclic polyolefin. The cyclic polyolefin to be acid-modified is the same as described above. The acid component used for the acid modification is the same as the acid component used for the modification of the polyolefin.

[0098] Preferred acid-modified polyolefins include polyolefins modified with a carboxylic acid or anhydride thereof, polypropylenes modified with a carboxylic acid or anhydride thereof, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0099] The thermally adhesive resin layer 4 may be formed of one type of resin alone, or may be formed of a blend polymer of two or more types of resins. Furthermore, the thermally adhesive resin layer 4 may be formed of only one layer, or may be formed of two or more layers of the same or different resins.

[0100] The heat-sealable resin layer 4 may contain a lubricant, etc., if necessary. When the heat-sealable resin layer 4 contains a lubricant, the occurrence of pinholes and cracks during molding of the exterior material for an electrical storage device can be suppressed. 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 kinds.

[0101] The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of the lubricant include those exemplified for the base layer 1. The lubricant may be used alone or in combination of two or more kinds.

[0102] When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount of the lubricant is not particularly limited. However, from the viewpoint of suppressing the occurrence of pinholes and cracks during molding of the exterior material for an electricity storage device, the amount of the lubricant is preferably 10 to 50 mg / m 2 about 15 to 40 mg / m 2 The degree of

[0103] The lubricant present on the surface of the heat-fusible resin layer 4 may be a lubricant exuded from the resin constituting the heat-fusible resin layer 4, or a lubricant applied to the surface of the heat-fusible resin layer 4.

[0104] The thickness of the heat-sealable resin layer 4 is not particularly limited as long as the heat-sealable resin layers are heat-sealed to each other to exhibit the function of sealing the electricity storage device element, and may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described below is 10 μm or more, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 5 described below is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0105] [Adhesive layer 5] In the packaging material for an electricity storage device of the present disclosure, the adhesive layer 5 is a layer that is provided, if necessary, between the barrier layer 3 (or the corrosion-resistant film) and the heat-sealable resin layer 4 in order to firmly bond them together.

[0106] The adhesive layer 5 is formed of a resin capable of bonding the barrier layer 3 and the heat-sealable resin layer 4. The resin used to form the adhesive layer 5 may be, for example, the same adhesive as exemplified for the adhesive layer 2. The resin used to form the adhesive layer 5 preferably contains a polyolefin skeleton, and examples thereof include the polyolefin and acid-modified polyolefin exemplified for the heat-sealable resin layer 4. The inclusion of a polyolefin skeleton in the resin constituting the adhesive layer 5 can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. In addition, 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 maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride at a wave number of 1760 cm is detected. -1 Nearby and wave number 1780cm -1 A peak derived from maleic anhydride is detected around this peak. However, if the degree of acid modification is low, the peak may be small and not detectable. In that case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0107] From the viewpoint of firmly adhering the barrier layer 3 and the heat-fusible resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. Particularly preferred examples of the acid-modified polyolefin include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0108] Furthermore, from the viewpoint of reducing the thickness of the electrical storage device exterior material while providing an electrical storage device exterior material with excellent shape stability after molding, the adhesive layer 5 is more preferably a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of the acid-modified polyolefin include those mentioned above.

[0109] The adhesive layer 5 is preferably 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, and is particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. The adhesive layer 5 is preferably at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. As the polyester, for example, an amide ester resin is preferable. Amide ester resins are generally produced by the reaction of 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. In addition, if unreacted compounds such as a compound having an isocyanate group, a compound having an oxazoline group, or a curing agent such as an epoxy resin remain in the adhesive layer 5, the presence of the unreacted compounds can be confirmed by a method selected from, for example, infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

[0110] In addition, from the viewpoint of further increasing the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocycle, a C=N bond, and a COC bond. 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 COC bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and polyurethane. It can be confirmed that the adhesive layer 5 is a cured product of a resin composition containing these curing agents by, for example, gas chromatography mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), or other methods.

[0111] The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively increasing the adhesion between the barrier layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate-based curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymerized or nurated products thereof, mixtures thereof, and copolymers with other polymers. In addition, adducts, biuret products, isocyanurates, etc. are also included.

[0112] The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This makes it possible to effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0113] 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.

[0114] The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This makes it possible to effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0115] An example of a compound having an epoxy group is an epoxy resin. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy group present 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 further preferably about 200 to 800. In the first disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

[0116] Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, etc. The epoxy resins may be used alone or in combination of two or more.

[0117] The ratio of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0118] The polyurethane is not particularly limited, and any known polyurethane can be used. The adhesive layer 5 may be, for example, a cured product of a two-component curing polyurethane.

[0119] The proportion of polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. This makes it possible to effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5 in an atmosphere containing a component that induces corrosion of the barrier layer, such as an electrolyte solution.

[0120] In addition, when the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

[0121] The upper limit of the thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, and about 5 μm or less, and the lower limit is preferably about 0.1 μm or more, and about 0.5 μm or more, and the thickness range is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, 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 a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably about 1 to 10 μm, and more preferably about 1 to 5 μm. In addition, when the resin exemplified in the heat-fusible resin layer 4 is used, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. For example, when the adhesive layer 5 is formed from an acid-modified polyolefin, the thickness of the adhesive layer 5 is preferably about 2 μm or more, more preferably 5 μm or more, and even more preferably 8 μm or more. In addition, when the adhesive layer 5 is formed from an acid-modified polyolefin, the thickness of the adhesive layer 5 is preferably about 50 μm or less, more preferably 40 μm or less. In addition, when the adhesive layer 5 is formed from an acid-modified polyolefin, the preferred 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, about 8 to 50 μm, or about 8 to 40 μm. In addition, when the adhesive layer 5 is an adhesive exemplified in the adhesive layer 2 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, for example, the adhesive layer 5 can be formed by applying the resin composition and curing it by heating or the like. When the resin exemplified for the thermally adhesive resin layer 4 is used, the thermally adhesive resin layer 4 and the adhesive layer 5 can be formed by extrusion molding, for example.

[0122] 3. Manufacturing method for exterior material for power storage device The method for producing the exterior material for an electric storage device is not particularly limited as long as a laminate is obtained by laminating the layers of the exterior material for an electric storage device of the present invention, and examples thereof include a method including a step of obtaining a laminate in which, from the outside, at least a surface coating layer 6, a base layer 1, a barrier layer 3, and a heat-sealable resin layer 4 are laminated. Specifically, the method for producing the exterior material for an electric storage device of the present disclosure includes a step of obtaining a laminate in which, from the outside, at least a surface coating layer 6, a base layer 1, a barrier layer 3, and a heat-sealable resin layer 4 are laminated, the surface coating layer 6 contains a resin and a filler, and the hardness of the outer surface of the surface coating layer 6 measured by a nanoindentation method in a 190° C. environment is 14.5 MPa or more.

[0123] An example of the method for producing the exterior material for an electricity storage device of the present invention is as follows. First, a laminate (hereinafter, sometimes referred to as "laminate A") is formed in which a base layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order. Specifically, the laminate A can be formed by a dry lamination method in which an adhesive used to form the adhesive layer 2 is applied to the base layer 1 or to the barrier layer 3, the surface of which has been chemically treated as necessary, by a coating method such as gravure coating or roll coating, and then dried, and the barrier layer 3 or base layer 1 is laminated thereon, and the adhesive layer 2 is cured.

[0124] Next, the heat-sealable resin layer 4 is laminated on the barrier layer 3 of the laminate A. When the heat-sealable resin layer 4 is directly laminated on the barrier layer 3, the heat-sealable resin layer 4 may be laminated on the barrier layer 3 of the laminate A by a method such as thermal lamination or extrusion lamination. When an adhesive layer 5 is provided between the barrier layer 3 and the heat-sealable resin layer 4, for example, (1) a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 by extruding them on the barrier layer 3 of the laminate A (co-extrusion lamination method, tandem lamination method), (2) a method of separately forming a laminate in which the adhesive layer 5 and the heat-sealable resin layer 4 are laminated, and laminating this on the barrier layer 3 of the laminate A by a thermal lamination method, or a method of forming a laminate in which the adhesive layer 5 is laminated on the barrier layer 3 of the laminate A, and laminating this on the heat-sealable resin layer 4 by a thermal lamination method. (3) a method in which a molten adhesive layer 5 is poured between the barrier layer 3 of the laminate A and a heat-sealable resin layer 4 previously formed into a sheet-like film, and the laminate A and the heat-sealable resin layer 4 are bonded together via the adhesive layer 5 (sandwich lamination method); (4) a method in which an adhesive for forming an adhesive layer 5 is solution-coated on the barrier layer 3 of the laminate A, and laminated by drying or baking, and then the heat-sealable resin layer 4 previously formed into a sheet-like film is laminated on the adhesive layer 5.

[0125] Next, a surface coating layer 6 is laminated on the surface of the base layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above-mentioned resin composition for forming the surface coating layer 6 to the surface of the base layer 1 and curing it. The order of the step of laminating the barrier layer 3 on the surface of the base layer 1 and the step of laminating the surface coating layer 6 on the surface of the base layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base layer 1, the barrier layer 3 may be formed on the surface of the base layer 1 opposite to the surface coating layer 6.

[0126] As described above, a laminate is formed which includes, from the outside, the surface coating layer 6 / the base layer 1 / the adhesive layer 2 (optional) / the barrier layer 3 / the adhesive layer 5 (optional) / the heat-sealable resin layer 4, and may be subjected to a heat treatment to strengthen the adhesion of the adhesive layer 2 and the adhesive layer 5 (optional). In addition, a colored layer may be provided between the base layer 1 and the barrier layer 3, as described above.

[0127] 4. Applications of exterior materials for energy storage devices The exterior material for an electricity storage device according to the present disclosure is used in a package for hermetically housing an electricity storage device element such as a positive electrode, a negative electrode, an electrolyte, etc. That is, an electricity storage device can be formed by housing an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte in a package formed from the exterior material for an electricity storage device according to the present disclosure.

[0128] Specifically, an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte is covered with the exterior material for an electricity storage device of the present disclosure in such a manner that a flange portion (a region where the heat-sealable resin layers contact each other) can be formed on the periphery of the electricity storage device element with the metal terminals connected to each of the positive electrode and the negative electrode protruding outward, and the heat-sealable resin layers of the flange portion are heat-sealed to provide an electricity storage device using the exterior material for an electricity storage device. When an electricity storage device element is housed in a package formed with the exterior material for an electricity storage device of the present disclosure, the package is formed so that the heat-sealable resin portion of the exterior material for an electricity storage device of the present disclosure faces inside (the surface in contact with the electricity storage device element).

[0129] The exterior material for an electric storage device of the present disclosure can be suitably used for an electric storage device such as a battery (including a condenser, a capacitor, etc.). The exterior material for an electric 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 secondary battery to which the exterior material for an electric storage device of the present disclosure is applied is not particularly limited, and examples thereof include lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, lead-acid batteries, nickel-hydrogen batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, examples of suitable applications of the exterior material for an electric storage device of the present disclosure include lithium ion batteries and lithium ion polymer batteries. EXAMPLES

[0130] 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.

[0131] <Manufacture of exterior materials for power storage devices> [Example 1] A stretched nylon (ONy) film (thickness 15 μm) was prepared as the substrate layer. An aluminum foil (JIS H4160:1994 A8021H-O (thickness 35 μm)) was prepared as the barrier layer. Next, the barrier layer and substrate layer were laminated by dry lamination using an adhesive (a two-liquid urethane adhesive containing a colorant) described below, and then aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate. Both sides of the aluminum foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum foil was performed using a treatment liquid consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m. 2 (dry weight) was applied to both sides of an aluminum foil by roll coating, and then baked.

[0132] Next, on the barrier layer of each laminate obtained above, maleic anhydride modified polypropylene as an adhesive layer (thickness 20 μm) and random polypropylene as a heat-sealable resin layer (thickness 20 μm) were co-extruded to laminate an adhesive layer / heat-sealable resin layer on the barrier layer. Furthermore, the following resin composition 1 was applied to the surface of the base layer of the obtained laminate to a thickness of 3 μm, and cured under a forming condition of 3 days in a temperature range of 40° C. to 100° C. to form a matte surface coating layer, and an exterior material for a power storage device was obtained, which is a laminate (total thickness 96 μm) in which the surface coating layer (3 μm) / base layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-sealable resin layer (20 μm) are laminated in order from the outside.

[0133] [Example 2] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that in forming the surface coating layer, the following resin composition 2 was used instead of resin composition 1 to form the surface coating layer.

[0134] [Example 3] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that in forming the surface coating layer, the following resin composition 3 was used instead of resin composition 1 to form the surface coating layer.

[0135] [Example 4] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that in forming the surface coating layer, the following resin composition 4 was used instead of resin composition 1 to form the surface coating layer.

[0136] [Example 5] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that in forming the surface coating layer, the following resin composition 5 was used instead of resin composition 1 to form the surface coating layer.

[0137] [Example 6] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that in forming the surface coating layer, the following resin composition 6 was used instead of resin composition 1 to form the surface coating layer.

[0138] [Comparative Example 1] An exterior material for an electricity storage device was obtained in the same manner as in Example 1, except that in forming the surface coating layer, the following resin composition 7 was used instead of resin composition 1 to form the surface coating layer.

[0139] <Resin composition used in forming the surface coating layer and forming conditions> (Resin Composition 1 (Used in Example 1)) A resin composition containing a resin (polyurethane formed from a mixture of two types of polyol compounds and an aromatic isocyanate compound), an inorganic filler (silica particles, average particle size 1 μm), an organic filler (average particle size 2 μm), and an olefin wax.

[0140] (Resin Composition 2 (Used in Example 2)) A resin composition containing a resin (polyurethane formed from a mixture of two types of polyol compounds and an aliphatic isocyanate compound), an inorganic filler (silica particles, average particle size 1 μm), an organic filler (average particle size 2 μm), and an olefin wax.

[0141] (Resin Composition 3 (Used in Example 3)) A resin composition containing a resin (polyurethane formed from a mixture of two types of polyol compounds and an aromatic isocyanate compound (the blending ratio of the two types of polyol compounds was changed from that of resin composition 1)), an inorganic filler (silica particles, average particle diameter 1 μm), an organic filler (average particle diameter 2 μm), and an olefin wax.

[0142] (Resin Composition 4 (Used in Example 4)) A resin composition in which the content of the olefin wax in the resin composition of Example 3 is 1 / 4

[0143] (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 / 8

[0144] (Resin Composition 6 (Used in Example 6)) The resin composition of Example 3 does not contain an olefin wax.

[0145] (Resin composition 7 (used in Comparative Example 1)) A resin composition comprising 100 parts by mass of a resin (polyurethane formed from a mixture of one type of polyol compound and an aliphatic isocyanate compound), 10 parts by mass of an inorganic filler (barium sulfate particles, average particle diameter 1 μm), and an organic filler (average particle diameter 2 μm).

[0146] [Hardness measured by nanoindentation method in 190℃ environment] The hardness was measured using a nanoindenter (HYSITRON's "TI950 TriboIndenter"). A Berkovich indenter (TI-0064) was used as the indenter of the nanoindenter. First, in a relative humidity of 50% and a temperature of 190°C, the indenter was applied to the surface of the surface coating layer of the exterior material for a power storage device (the surface where the measurement target is exposed, and the surface perpendicular to the thickness direction of each layer) from a direction parallel to the thickness direction, and the indenter was pressed into the surface coating layer from the surface to a load of 25 μN over 10 seconds, and the state was held for 15 seconds, and then the load was removed over 10 seconds. The average value of N=5 measured by shifting the measurement point was taken as the hardness. The results are shown in Table 1. The surface into which the indenter was pressed was the part exposed on the surface of the exterior material for a power storage device. The sample was fixed using a commercially available instant adhesive. The measurement results were rounded off to the nearest tenth.

[0147] [Hardness measured by nanoindentation method at 23℃] The hardness was measured using a nanoindenter (HYSITRON's "TI950 TriboIndenter"). A Berkovich indenter (TI-0039) was used as the indenter of the nanoindenter. First, in a relative humidity of 50% and a temperature of 23°C, the indenter was applied to the surface of the surface coating layer of the exterior material for an electric storage device (the surface where the surface coating layer is exposed, parallel to the thickness direction of each layer) from a direction perpendicular to the thickness direction, and the indenter was pressed 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 point was taken as the hardness. The results are shown in Table 1. The surface into which the indenter was pressed was a resin portion where a cross section of the surface coating layer (cross section in the thickness direction of the surface coating layer) was exposed, obtained by cutting the exterior material for an electric storage device in the thickness direction so as to pass through the center (may be near the center). In addition, in measuring the hardness of the surface coating layer, the indenter was pressed into a portion (resin portion) where no filler was present on the surface of the surface coating layer. The measurement results were rounded off to the nearest tenth. The organic filler contained in the surface coating layers of Examples 1-6 and Comparative Example 1 was the same, and the hardness of the surface coating layer of Example 2 measured by pressing the indenter into the portion where the organic filler was present was 496.1 MPa. Cutting was performed using a commercially available rotary microtome. The measurement results were rounded off to the nearest tenth.

[0148] [Evaluation of matte finish design after heat sealing] As shown in the schematic diagram of FIG. 4, each exterior material for a power storage device was cut to 60 mm (TD direction) × 200 mm (MD direction) (FIG. 4a). Next, the exterior material for a power storage device was folded in half in the MD direction at the fold P (middle of the MD direction) so that the heat-sealable resin layers faced each other (FIG. 4b). Next, the heat-sealable resin layers were heat-sealed to each other at a heat seal width of 7 mm (a 7 mm wide stainless steel plate was used as a heat seal bar) about 10 mm inside in the MD direction (FIG. 4c) under the conditions of a temperature of 210°C, a surface pressure of 0.5 MPa, and a time of 6 seconds. The shaded area S is the heat-sealed area. The difference in surface gloss between the shaded area and the area other than the shaded area was visually confirmed, and the matte design after heat sealing was evaluated according to the following criteria. The results are shown in Table 1. A: In the heat sealed portion, the matte design before heat sealing was well maintained. B: The heat sealed area was glossy depending on the angle from which it was viewed, and the matte design before the heat seal was somewhat diminished. C: The heat sealed area was glossy, and the matte design before the heat sealing was damaged.

[0149] [Arithmetic mean roughness Ra 1 ,Ra 2 Measurement of For each exterior material for an electricity storage device before and after the above-mentioned [Evaluation of the matte finish design after heat sealing], the arithmetic mean roughness Ra of the surface coating layer (the part to be heat sealed) before heat sealing of the surface coating layer was measured. 1 and the arithmetic mean roughness Ra of the heat-sealed portion of the surface coating layer after heat sealing. 2 and were measured using an optical surface texture measuring instrument (Zygo New View 7300). 1 ,Ra 2 , and their ratio Ra 2 / Ra 1 The rate of change is shown in Table 1.

[0150] [Moldability] Each electrical storage device exterior material was cut into a rectangle with a length (MD) of 90 mm and a width (TD) of 150 mm to prepare a test sample. The MD of the electrical storage device exterior material corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the electrical storage device exterior material corresponds to the TD of the aluminum alloy foil. The test sample was placed in a 25°C environment and molded into a rectangular mold (female mold, the surface has a maximum height roughness (nominal value of Rz) of 3.2μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 1 (Reference), corner R2.0mm, ridge R1.0mm) with an aperture of 31.6mm (MD) x 54.5mm (TD) and a corresponding mold (male mold, the surface of the ridgeline has a maximum height roughness (nominal value of Rz) of 1.6μm as specified in Table 2 of the surface roughness standard for comparison in JIS B 0659-1:2002, Annex 1 (Reference), corner R2.0mm, ridge R1.0mm). The maximum height roughness (nominal value of Rz) specified in Table 2 of the comparative surface roughness standard piece is 3.2 μm. Ten test samples were cold-formed (one-stage drawing) with a pressing pressure (surface pressure) of 0.9 MPa and a molding depth of 5 mm using a corner R2.0 mm and a ridge R1.0 mm. At this time, the test samples were placed on a female mold so that the heat-sealable resin layer side was located on the male mold side and molding was performed. In addition, the clearance between the male mold and the female mold was 0.3 mm. The test samples after cold forming were evaluated for the matte design after molding according to the following criteria. The following evaluation AC criteria were applied when 6 or more (more than half) of the 10 test samples met these evaluation criteria. The results are shown in Table 1. A: The matte design was well maintained even after molding, and there was no cracking or peeling of the surface coating layer. B: After molding, there was no cracking or peeling of the surface coating layer, but the surface of the surface coating layer became glossy, damaging the matte design. C: After molding, gloss appeared on the surface of the surface coating layer, damaging the matte design, and furthermore cracks and peeling occurred in the surface coating layer.

[0151] [Table 1]

[0152] In the exterior packaging material for an electricity storage device of Example 1-6, the surface coating layer contains a resin and a filler, and the hardness of the outer surface of the surface coating layer measured by a nanoindentation method is 14.5 MPa or more in an environment of 190° C. In the exterior packaging material for an electricity storage device of Example 1-6, the matte design provided by the surface coating layer containing the filler is prevented from being damaged by heat sealing.

[0153] As described above, the present disclosure provides the following aspects of the invention. Item 1. The device is composed of a laminate including, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer; The surface coating layer includes a resin and a filler, An exterior material for an electricity storage device, wherein the hardness of the outer surface of the surface coating layer, as measured by a nanoindentation method in an environment of 190°C, is 14.5 MPa or more. Item 2. The exterior material for an electricity storage device according to Item 1, wherein the hardness of the resin of the surface coating layer, as measured by a nanoindentation method on a cross section in a thickness direction of the surface coating layer in a 23° C. environment, is 420.4 MPa or less. Item 3. The exterior material for an electricity storage device according to Item 1 or 2, wherein the hardness of the filler in the surface coating layer, as measured by a nanoindentation method on a cross section in a thickness direction of the surface coating layer in a 23° C. environment, is 300.0 MPa or more. Item 4. Arithmetic mean roughness Ra of the outer surface of the surface coating layer 1 Item 4. The exterior packaging material for an electricity storage device according to any one of items 1 to 3, wherein the thickness of the outer casing is 0.3 μm or more. Item 5. Using a stainless steel plate, the outer surface of the surface coating layer is heated and pressed under conditions of a temperature of 190°C, a surface pressure of 0.5 MPa, and a time of 6 seconds. After that, the arithmetic average roughness Ra of the outer surface of the surface coating layer is measured. 2 The arithmetic mean roughness Ra of the outer surface of the surface coating layer before the outer surface of the surface coating layer is heated and pressed.1 Ratio to Ra 2 / Ra 1 5. The exterior packaging material for an electricity storage device according to any one of items 1 to 4, wherein the value is 0.7 or more. Item 6. The exterior material for an electricity storage device according to any one of Items 1 to 5, further comprising an adhesive layer between the base layer and the barrier layer. Item 7. The exterior material for an electricity storage device according to Item 6, wherein the adhesive layer is colored. Item 8. The exterior material for an electricity storage device according to any one of Items 1 to 7, further comprising a colored layer between the base layer and the barrier layer. Item 9. A method for producing an exterior material for an electricity storage device, comprising: The method includes a step of obtaining a laminate in which, from the outside, at least a surface coating layer, a base layer, a barrier layer, and a thermally adhesive resin layer are laminated, The surface coating layer includes a resin and a filler, A method for producing an exterior material for an electricity storage device, wherein the hardness of the outer surface of the surface coating layer, as measured by a nanoindentation method in an environment of 190°C, is 14.5 MPa or more. Item 10. An electricity storage device, in which an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the exterior material for an electricity storage device according to any one of Items 1 to 8. [Explanation of symbols]

[0154] 1 Base material layer 2 Adhesive layer 3. Barrier layer 4 Heat-fusible resin layer 5 Adhesive layer 6 Surface coating layer 10. Exterior materials for power storage devices

Claims

1. The laminate includes, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, The surface coating layer includes a resin and a filler, The surface coating layer contains a colorant, An exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

2. The laminate includes, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, The surface coating layer includes a resin and a filler, The surface coating layer contains titanium oxide, An exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

3. The laminate includes, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, The surface coating layer includes a resin and a filler, The surface coating layer contains silica, An exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

4. The laminate includes, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, The surface coating layer includes a resin and a filler, The surface coating layer contains kaolin, An exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

5. The laminate includes, in order from the outside, at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, The surface coating layer includes a resin and a filler, the surface coating layer contains at least two selected from the group consisting of silica, talc, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, gold, aluminum, copper, and nickel; An exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

6. The hardness of the resin of the surface coating layer measured by a nanoindentation method in a cross section in a thickness direction of the surface coating layer in a 23 ° C. environment is 420.4 MPa or less. The exterior material for a storage battery device according to any one of claims 1 to 5.

7. The hardness of the filler of the surface coating layer measured by a nanoindentation method in a cross section in the thickness direction of the surface coating layer in a 23 ° C. environment is 300.0 MPa or more. The exterior material for a storage battery device according to any one of claims 1 to 6.

8. The arithmetic mean roughness Ra of the outer surface of the surface coating layer 1 The exterior material for an electricity storage device according to any one of claims 1 to 7, wherein the thickness of the outer casing is 0.3 µm or more.

9. The arithmetic mean roughness Ra of the outer surface of the surface coating layer after heating and pressing the outer surface of the surface coating layer under conditions of a temperature of 190° C., a surface pressure of 0.5 MPa, and a time of 6 seconds using a stainless steel plate 2 The arithmetic mean roughness Ra of the outer surface of the surface coating layer before the outer surface of the surface coating layer is heated and pressed 1 Ratio to Ra 2 / Ra 1 The exterior material for an electricity storage device according to any one of claims 1 to 8, wherein is 0.7 or more.

10. The exterior material for an electricity storage device according to any one of claims 1 to 9, further comprising an adhesive layer between the base layer and the barrier layer.

11. The exterior material for an electricity storage device according to claim 10 , wherein the adhesive layer is colored.

12. The exterior material for an electricity storage device according to any one of claims 1 to 11, further comprising a colored layer between the base layer and the barrier layer.

13. A method for producing an exterior material for an electricity storage device, comprising: The method includes a step of obtaining a laminate in which, from the outside, at least a surface coating layer, a base layer, a barrier layer, and a thermally adhesive resin layer are laminated, The surface coating layer includes a resin and a filler, The surface coating layer contains a colorant, A method for producing an exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

14. A method for producing an exterior material for an electricity storage device, comprising: The method includes a step of obtaining a laminate in which, from the outside, at least a surface coating layer, a base layer, a barrier layer, and a thermally adhesive resin layer are laminated, The surface coating layer includes a resin and a filler, The surface coating layer contains titanium oxide, A method for producing an exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

15. A method for producing an exterior material for an electricity storage device, comprising: The method includes a step of obtaining a laminate in which, from the outside, at least a surface coating layer, a base layer, a barrier layer, and a thermally adhesive resin layer are laminated, The surface coating layer includes a resin and a filler, The surface coating layer contains silica, A method for producing an exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

16. A method for producing an exterior material for an electricity storage device, comprising: The method includes a step of obtaining a laminate in which, from the outside, at least a surface coating layer, a base layer, a barrier layer, and a thermally adhesive resin layer are laminated, The surface coating layer includes a resin and a filler, The surface coating layer contains kaolin, A method for producing an exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

17. A method for producing an exterior material for an electricity storage device, comprising: The method includes a step of obtaining a laminate in which, from the outside, at least a surface coating layer, a base layer, a barrier layer, and a thermally adhesive resin layer are laminated, The surface coating layer includes a resin and a filler, the surface coating layer contains at least two selected from the group consisting of silica, talc, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, gold, aluminum, copper, and nickel; A method for producing an exterior material for an electricity storage device, wherein the hardness of an outer surface of the surface coating layer is 14.5 MPa or more when measured by a nanoindentation method in a 190°C environment.

18. An electricity storage device, comprising: an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte; and the electricity storage device element is housed in a package formed from the exterior material for an electricity storage device according to any one of claims 1 to 12.

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