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

Abstract

Disclosed is an exterior material for a power storage device, the exterior material being formed of a multilayer body that includes at least a barrier layer and a thermally fusible resin layer in this order. The barrier layer is composed of a cladding material. The cladding material includes at least a first metal layer that constitutes a surface on the thermally fusible resin layer side and a second metal layer that constitutes a surface opposite to the thermally fusible resin layer-side surface. The first metal layer is an aluminum layer that is formed of aluminum or an aluminum alloy. With respect to the TG-DTA differential thermal analysis of the cladding material, an endothermic peak due to melting is present at 1,000°C or higher, and no weight change occurs at the temperature at which the endothermic peak is present.

Description

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

[0001] The present disclosure relates to an exterior material for an electricity storage device, a method for producing the same, and an electricity storage device.

[0002] Various types of electricity storage devices have been developed, and in all of them, packaging materials (exterior materials) are essential components for sealing electricity storage device elements such as electrodes and electrolytes. Conventionally, metal exterior materials have been widely used as exterior materials for electricity storage devices.

[0003] Meanwhile, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., electricity storage devices are being required to have a variety of shapes as well as to be thinner and lighter in weight. 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 on how much they can be made lighter.

[0004] Therefore, a film-like packaging material in which a base material, a barrier layer, and a heat-sealable resin layer are sequentially laminated has been proposed as a packaging material for an electricity storage device that can be easily processed into various shapes and can be made thinner and lighter (see, for example, Patent Document 1).

[0005] In such film-like packaging materials, recesses are generally formed by cold forming, and energy storage device elements such as electrodes and electrolytes are placed in the spaces formed by the recesses. The heat-sealable resin layers are then heat-sealed together to obtain an energy storage device in which the energy storage device elements are housed inside the packaging material.

[0006] Japanese Patent Application Laid-Open No. 2008-287971

[0007] As the barrier layer of the above-mentioned film-like packaging material for an electricity storage device, an aluminum alloy foil is generally used.

[0008] In an electricity storage device, an electrolyte is housed in a package formed from an exterior material for an electricity storage device, and therefore the exterior material for an electricity storage device is required to have high corrosion resistance.

[0009] Since aluminum has low reactivity with electrolytes, the use of an aluminum alloy foil in the barrier layer can improve the corrosion resistance of the electrical storage device packaging material. Furthermore, the corrosion resistance of the electrical storage device packaging material can be further improved by applying a chemical conversion treatment to the surface of the aluminum alloy foil.

[0010] In recent years, there have been numerous reports of fires involving power storage devices (such as lithium-ion batteries) used in vehicles, mobile devices, etc. Fires from power storage devices are recognized as a risk, and various countermeasures are being taken from various quarters.

[0011] Among the materials that make up the exterior packaging for energy storage devices, the aluminum alloy foil used in the barrier layer is a metal, so it has a high melting point and is less likely to melt or burn compared to materials made of resin alone. However, to ensure even greater safety, we investigated ways to further improve its resistance to burning.

[0012] As described above, the inventors of the present disclosure have conducted studies to improve the burn resistance of an electrical storage device packaging material while maintaining excellent corrosion resistance.

[0013] A primary object of the present disclosure is to provide an exterior material for an electricity storage device that has excellent fire resistance and corrosion resistance. Another object of the present disclosure is to provide a method for manufacturing the exterior material for an electricity storage device, and an electricity storage device using the exterior material for an electricity storage device.

[0014] The inventors of the present disclosure have conducted extensive research to solve the above-mentioned problems, and as a result have found that in a packaging material for an electricity storage device constituted by a laminate including at least a barrier layer and a heat-sealable resin layer in this order, the packaging material for an electricity storage device exhibits burn resistance and corrosion resistance by using, in the barrier layer, a clad material including an aluminum layer in which an endothermic peak due to melting is observed at 1000°C or higher.

[0015] The present disclosure was completed through further investigation based on these findings. That is, the present disclosure provides the invention of the following aspects: An exterior packaging material for an electricity storage device, which is composed of a laminate including at least a base layer, a barrier layer, and a thermally adhesive resin layer in this order, wherein the barrier layer is composed of a clad material, and the clad material includes at least a first metal layer that forms a surface on the thermally adhesive resin layer side and a second metal layer that forms a surface on the opposite side to the thermally adhesive resin layer side, wherein the first metal layer is an aluminum layer made of aluminum or an aluminum alloy, and wherein the clad material exhibits an endothermic peak due to melting at 1000°C or higher in TG-DTA measurement.

[0016] According to the present disclosure, it is possible to provide a packaging material for an electricity storage device that is composed of a laminate having at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, and that has excellent fire resistance and corrosion resistance. The present disclosure also makes it possible to provide a method for manufacturing a packaging material for an electricity storage device, and an electricity storage device.

[0017] Fig. 1 is a schematic diagram showing an example of the cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. Fig. 2 is a schematic diagram showing an example of the cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. Fig. 3 is a schematic diagram showing an example of the cross-sectional structure of an exterior material for an electricity storage device according to the present disclosure. Fig. 4 is a schematic diagram for explaining a method of housing an electricity storage device element in a package formed from an exterior material for an electricity storage device according to the present disclosure.

[0018] The electrical storage device packaging material of the present disclosure is composed of a laminate including at least a barrier layer and a heat-sealable resin layer in this order, the barrier layer being composed of a clad material, the clad material including at least a first metal layer constituting a surface on the heat-sealable resin layer side and a second metal layer constituting a surface opposite to the heat-sealable resin layer side, the first metal layer being an aluminum layer formed of aluminum or an aluminum alloy, and the clad material being characterized in that, in differential thermal analysis measurement by TG-DTA, an endothermic peak due to melting is observed at 1000°C or higher and there is no weight change at the temperature at which the endothermic peak is observed. The electrical storage device packaging material of the present disclosure having such a configuration can exhibit excellent fire resistance and corrosion resistance.

[0019] The exterior packaging material for an electricity storage device of the present disclosure will be described in detail below. Note that in this disclosure, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the notation 2 to 15 mm means 2 mm or more and 15 mm or less. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, separately described upper and lower limits, upper and lower limits, or lower and lower limits may each be combined to form a numerical range. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0020] The MD (Machine Direction) and TD (Transverse Direction) of an electrical storage device packaging material can be identified, for example, by the following method. One method for confirming the MD of an electrical storage device packaging material is to observe a cross section of the heat-sealable resin layer of the electrical storage device packaging material using an electron microscope to confirm the sea-island structure. In this method, the direction parallel to the cross section in which the average diameter of the island shapes in the direction perpendicular to the thickness direction of the heat-sealable resin layer is greatest can be determined to be the MD. Specifically, the longitudinal cross section of the heat-sealable resin layer and each cross section (a total of 10 cross sections) angled 10 degrees from the direction parallel to the longitudinal cross section up to the direction perpendicular to the longitudinal cross section are each observed using an electron microscope to confirm the sea-island structure. Next, the shape of each island is observed in each cross section. For each island shape, the straight-line distance connecting the leftmost end in the direction perpendicular to the thickness direction of the heat-sealable resin layer to the rightmost end in the same direction is defined as the diameter y. For each cross section, the average of the diameters y of the top 20 island shapes in descending order of diameter y is calculated. The direction parallel to the cross section with the largest average diameter y of the island shape is determined to be the MD.

[0021] 1. Laminated Structure of the Electricity Storage Device Exterior Material As shown in, for example, FIGS. 1 to 4 , the exterior material 10 for an electricity storage device according to the present disclosure is composed of a laminate including at least a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4, in this order. In the exterior material 10 for an electricity storage device, the base material layer 1 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 peripheries are heat-sealed to form a space, in which the electricity storage device element is housed. 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 the reference, and the heat-sealable resin layer 4 side is the inner side relative to the barrier layer 3, and the base material layer 1 side is the outer side relative to the barrier layer 3.

[0022] The packaging material 10 for an electricity storage device according to the present disclosure may be composed of a laminate including at least a barrier layer 3 and a heat-sealable resin layer 4 in this order. In this case, in the laminate, the base material layer 1 is a layer that is provided as needed, and the side of the barrier layer 3 opposite to the heat-sealable resin layer 4 side is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer.

[0023] As shown in Figures 2 to 4, for example, the packaging 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. Furthermore, as shown in Figures 3 and 4, for example, the packaging material 10 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. Furthermore, as shown in Figure 4, a surface coating layer 6 or the like may be provided on the outer side of the base material layer 1 (the side opposite to the heat-sealable resin layer 4 side), if necessary.

[0024] The thickness of the laminate constituting the electrical storage device exterior material 10 is not particularly limited, but from the viewpoint of cost reduction, improvement of energy density, etc., examples of the thickness include about 300 μm or less, preferably about 250 μm or less, about 210 μm or less, about 190 μm or less, about 180 μm or less, about 155 μm or less, and about 120 μm or less. Furthermore, from the viewpoint of maintaining the function of the electrical storage device exterior material to protect the electrical storage device elements, the thickness of the laminate constituting the electrical storage device exterior material 10 is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, about 155 μm or more, and about 190 μm or more. Furthermore, preferred ranges for the laminate constituting the exterior packaging material 10 for an electricity storage device are, for example, about 35 to 300 μm, about 35 to 250 μm, about 35 to 210 μm, about 35 to 190 μm, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 300 μm, about 45 to 250 μm, about 45 to 210 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 300 μm, about 60 to 250 μm, and about 60 to 300 μm. Examples of the thickness include about 210 μm, about 60 to 190 μm, about 60 to 180 μm, about 60 to 155 μm, about 60 to 120 μm, about 155 to 300 μm, about 155 to 250 μm, about 155 to 210 μm, about 155 to 190 μm, about 155 to 180 μm, about 190 to 300 μm, about 190 to 250 μm, and about 190 to 210 μm. In particular, when making the power storage device lightweight and thin, about 60 to 155 μm is preferred, and when improving formability, about 155 to 190 μm is preferred.

[0025] In the electrical storage device packaging material 10, the ratio of the total thickness of the base material layer 1, the adhesive layer 2 (which is provided as needed), the barrier layer 3, the adhesive layer 5 (which is provided as needed), the heat-sealable resin layer 4, and the surface coating layer 6 (which is provided as needed) to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the electrical storage device packaging material 10 of the present disclosure includes the base material layer 1, the adhesive layer 2, the barrier layer 3, the adhesive layer 5, and the heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, even when the electrical storage device packaging material 10 of the present disclosure is a laminate including a substrate layer 1, an adhesive layer 2, a barrier layer 3, and a heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0026] Furthermore, when the electrical storage device packaging material 10 does not include the base material layer 1, the ratio of the total thickness of the barrier layer 3, the adhesive layer 5 provided as needed, the heat-sealable resin layer 4, and the surface coating layer 6 provided as needed to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the electrical storage device packaging material 10 of the present disclosure includes the barrier layer 3, the adhesive layer 5, and the heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, even when the electrical storage device packaging material 10 of the present disclosure is a laminate including a barrier layer 3 and a heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the electrical storage device packaging material 10 can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0027] 2. Layers forming the packaging material for an electricity storage device [Substrate 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 packaging material for an electricity storage device. The substrate layer 1 is located on the outer layer side of the packaging material for an electricity storage device. The substrate layer 1 is a layer that is provided as needed.

[0028] There are no particular limitations on the material forming the substrate layer 1, as long as it functions as a substrate, i.e., has at least insulating properties. The substrate layer 1 can be formed using, for example, a resin, which may contain an additive described below.

[0029] When the substrate layer 1 is formed of a resin, the substrate layer 1 can be formed of, for example, a resin film. When the substrate layer 1 is formed of a resin film, a pre-formed resin film may be used as the substrate layer 1 when the substrate layer 1 is laminated with the barrier layer 3 or the like to produce the electrical storage device packaging material 10 of the present disclosure. Alternatively, the resin forming the substrate layer 1 may be formed into a film on the surface of the barrier layer 3 or the like by extrusion molding, coating, or the like to form the substrate layer 1 formed of a resin film. The resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially stretched films and biaxially stretched films, with biaxially stretched films being preferred. Examples of stretching methods for forming a biaxially stretched film include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying the resin include roll coating, gravure coating, and extrusion coating.

[0030] Examples of resins that form the base layer 1 include polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. The resin that forms the base layer 1 may also be a copolymer of these resins, a modified version of the copolymer, or a mixture of these resins.

[0031] The base layer 1 preferably contains these resins as the main component, and more preferably contains polyester or polyamide as the main component. Here, "main component" means that the content of the resin component contained in the base layer 1 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the base layer 1 contains polyester or polyamide as the main component" means that the content of polyester or polyamide among the resin components contained in the base layer 1 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0032] Of these, polyester and polyamide are preferred as the resin for forming the base layer 1.

[0033] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters in which ethylene terephthalate is the main repeating unit. Specific examples include copolymer 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 / decanedicarboxylate). These polyesters may be used alone or in combination of two or more.

[0034] 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 (where I represents isophthalic acid and T represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid; and aromatic polyamides 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, which 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.

[0035] The base layer 1 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, and preferably includes at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, and 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.

[0036] The base material layer 1 may be a single layer or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or a laminate of resin films formed by co-extrusion of resins into two or more layers. Furthermore, a laminate of resin films formed by co-extrusion of resins into two or more layers may be used as the base material layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base material layer 1.

[0037] Specific examples of the laminate of two or more resin films in the base layer 1 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. A laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, or a laminate of two or more stretched polyester films is preferred. 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. 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. Furthermore, since polyester resins are less likely to discolor when an electrolytic solution adheres to their surface, it is preferred that the polyester resin film be located as the outermost layer of the base layer 1 when the base layer 1 is a laminate of two or more resin films. In the laminate of a polyester resin film and a polyamide resin film, preferred ranges of the thickness of the polyester resin film are about 2 to 33 μm, about 2 to 28 μm, about 2 to 23 μm, about 2 to 18 μm, about 2 to 11 μm, about 2 to 8 μm, about 10 to 33 μm, about 10 to 28 μm, about 10 to 23 μm, about 10 to 18 μm, about 18 to 33 μm, and about 18 to 28 μm. and about 18 to 23 μm. Preferred ranges of the thickness of the polyamide resin film include about 2 to 33 μm, about 2 to 28 μm, about 2 to 23 μm, about 2 to 18 μm, about 2 to 11 μm, about 2 to 8 μm, about 10 to 33 μm, about 10 to 28 μm, about 10 to 23 μm, about 10 to 18 μm, about 18 to 33 μm, about 18 to 28 μm, and about 18 to 23 μm.

[0038] When the base layer 1 is a laminate of two or more resin film layers, the two or more resin film layers may be laminated via an adhesive. Examples of preferred adhesives include those similar to those exemplified for adhesive layer 2 described below. The method for laminating two or more resin film layers is not particularly limited, and known methods can be used, such as dry lamination, sandwich lamination, extrusion lamination, and thermal lamination, with dry lamination being preferred. When laminating using the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive may be, for example, about 2 to 5 μm. Alternatively, an anchor coat layer may be formed on the resin film before lamination. Examples of the anchor coat layer include those similar to those exemplified for adhesive layer 2 described below. In this case, the thickness of the anchor coat layer may be, for example, about 0.01 to 1.0 μm.

[0039] Furthermore, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and colorants may be present on at least one of the surface and the interior of the base material layer 1. Only one type of additive may be used, or two or more types may be mixed and used.

[0040] In the present disclosure, from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferable that a lubricant be present on at least one of the surface and the interior of the base material layer 1. The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylolamides include methylol stearic acid amide. 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 adipamide, 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 adipamide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamidoethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide.The lubricant may be used alone or in combination of two or more kinds, and it is preferable to use a combination of two or more kinds.

[0041] When a lubricant is present on the surface of the base layer 1, the amount of the lubricant is not particularly limited, but may be, for example, about 3 mg / m 2 or more, preferably about 4 mg / m 2 Above, about 5mg / m 2 The amount of lubricant present on the surface of the base layer 1 is, for example, about 15 mg / m 2 or less, preferably about 14 mg / m 2 Below, about 10mg / m 2 The preferred range of the amount of lubricant present on the surface of the base layer 1 is 3 to 15 mg / m 2 Degree, 3-14mg / m 2 Degree, 3-10mg / m 2 Degree, 4-15mg / m 2 Degree, 4-14mg / m 2 degree, 4-10mg / m 2 degree, 5-15mg / m 2 Degree, 5-14mg / m 2 degree, 5-10mg / m 2 The degree of

[0042] The lubricant present on the surface of the base layer 1 may be a lubricant exuded from the resin constituting the base layer 1, or a lubricant applied to the surface of the base layer 1.

[0043] The thickness of the substrate layer 1 is not particularly limited as long as it functions as a substrate, but may be, for example, about 3 μm or more, preferably about 10 μm or more, and may be, for example, about 100 μm or less, about 90 μm or less, about 70 μm or less, or about 50 μm or less, preferably about 35 μm or less, about 11 μm or less, or about 8 μm or less. In addition, preferred ranges of the thickness of the base layer 1 include about 3 to 100 μm, about 3 to 90 μm, about 3 to 70 μm, about 3 to 50 μm, about 3 to 35 μm, about 3 to 11 μm, about 3 to 8 μm, about 10 to 100 μm, about 10 to 90 μm, about 10 to 70 μm, about 10 to 50 μm, about 10 to 35 μm, and about 10 to 11 μm. In particular, when making the power storage device lighter and thinner, about 3 to 35 μm, about 3 to 11 μm, and about 3 to 8 μm are preferred, and when improving formability, about 35 to 50 μm is preferred. When the base layer 1 is a laminate of two or more resin films, the thickness of the resin films constituting each layer is not particularly limited, but can be, for example, about 2 μm or more, preferably about 10 μm or more, or about 18 μm or more. The thickness of the resin film constituting each layer is, for example, about 33 μm or less, preferably about 28 μm or less, about 23 μm or less, about 18 μm or less, about 11 μm or less, or about 8 μm or less. Preferred ranges for the thickness of the resin film constituting each layer include about 2 to 33 μm, about 2 to 28 μm, about 2 to 23 μm, about 2 to 18 μm, about 2 to 11 μm, about 2 to 8 μm, about 10 to 33 μm, about 10 to 28 μm, about 10 to 23 μm, about 10 to 18 μm, about 10 to 11 μm, about 18 to 33 μm, about 18 to 28 μm, and about 18 to 23 μm.

[0044] The base material layer 1 contains a colorant, which allows the electrical storage device packaging material to be colored. Known colorants such as pigments and dyes can be used as the colorant. Only one type of colorant may be used, or two or more types may be mixed together.

[0045] The type of pigment is not particularly limited as long as it does not impair the function as a substrate of the substrate layer 1. 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 finely powdered mica and fish scale foil.

[0046] Among colorants, carbon black is preferred for making the exterior material for an electricity storage device black, and mica is preferred from the viewpoint of dissipating heat generated from the electricity storage device.

[0047] The average particle size of the pigment is not particularly limited and may be, for example, about 0.03 to 5 μm, and preferably about 0.05 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution analyzer.

[0048] The content of the colorant in the base layer 1 is not particularly limited as long as the packaging material for an electricity storage device is colored, and may be, for example, about 5 to 60 mass %, and preferably about 10 to 40 mass %.

[0049] [Adhesive Layer 2] In the packaging material for an electricity storage device according to the present disclosure, the adhesive layer 2 is a layer that is provided between the base layer 1 and the barrier layer 3 as needed for the purpose of increasing the adhesion between them.

[0050] The adhesive layer 2 is formed from an adhesive capable of bonding the base material layer 1 and the barrier layer 3. There are no limitations on the adhesive used to form the adhesive layer 2, and it may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, etc. It may also 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. The adhesive layer 2 may be a single layer or multiple layers.

[0051] Specific examples of adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolymer polyamides; polyolefin-based resins such as 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 with two or more. Among these adhesive components, polyurethane adhesives are preferred. Furthermore, the adhesive strength of these adhesive component resins can be increased by using an appropriate curing agent in combination. The curing agent is selected appropriately from polyisocyanates, multifunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, and the like, depending on the functional groups possessed by the adhesive components.

[0052] Examples of polyurethane adhesives include polyurethane adhesives containing a first part containing a polyol compound and a second part containing an isocyanate compound. Two-component curing polyurethane adhesives are preferred, with a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the first part and an aromatic or aliphatic polyisocyanate as the second part. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance, and an isocyanate compound. Examples of polyurethane adhesives include polyurethane adhesives containing a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance, and a polyol compound. Examples of polyurethane adhesives include polyurethane adhesives obtained by reacting a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance with moisture, such as in the air, and then curing the polyurethane compound. Polyester polyols having hydroxyl groups on the side chains in addition to terminal hydroxyl groups in the repeating unit are preferably used as the polyol compound. Examples of the second part 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). Also included are polyfunctional isocyanate-modified compounds of one or more of these diisocyanates. Multimers (e.g., trimers) can also be used as polyisocyanate compounds. Examples of such multimers include adducts, biurets, and nurates. Forming the adhesive layer 2 using a polyurethane adhesive provides the electrical storage device exterior material with excellent electrolyte resistance, preventing peeling of the base layer 1 even when the electrolyte adheres to the side surface.

[0053] Furthermore, the adhesive layer 2 may contain other components as long as they do not impair adhesion, and may contain colorants, thermoplastic elastomers, tackifiers, fillers, etc. By including a colorant in the adhesive layer 2, the electrical storage device packaging material can be colored. Known colorants such as pigments and dyes can be used as colorants. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[0054] 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 finely powdered mica and fish scale foil.

[0055] Among colorants, carbon black is preferred for making the exterior material for an electricity storage device black, and mica is preferred from the viewpoint of dissipating heat generated from the electricity storage device.

[0056] The average particle size of the pigment is not particularly limited and may be, for example, about 0.03 to 5 μm, and preferably about 0.05 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution analyzer.

[0057] The content of the colorant in the adhesive layer 2 is not particularly limited as long as it colors the packaging material for an electricity storage device, and may be, for example, about 5 to 60 mass %, and preferably 10 to 40 mass %.

[0058] 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 is, for example, about 1 μm or more, about 2 μm or more. The thickness of the adhesive layer 2 is, for example, about 10 μm or less, about 5 μm or less. Preferred ranges for the thickness of the adhesive layer 2 include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[0059] [Colored Layer] The colored layer is a layer (not shown) that is provided between the base material layer 1 and the barrier layer 3 as needed. 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. Alternatively, a colored layer may be provided on the outside of the base material layer 1. By providing a colored layer, the packaging material for an electricity storage device can be colored.

[0060] The colored layer can be formed, for example, by applying ink containing a colorant to the surface of the base layer 1 or the surface of the barrier layer 3. Known colorants such as pigments and dyes can be used as the colorant. Only one type of colorant may be used, or two or more types may be mixed together.

[0061] Specific examples of the colorant contained in the colored layer include the same as those exemplified in the section [Adhesive layer 2].

[0062] [Barrier Layer 3] In the packaging material for an electricity storage device, the barrier layer 3 is a layer that prevents at least moisture from penetrating. In the packaging material for an electricity storage device of the present disclosure, the barrier layer 3 is made of a clad material.

[0063] A clad material is a metal material made by bonding two or more different metals. Clad materials can exhibit composite properties that cannot be achieved with a single material. For the barrier layer 3 of the present disclosure, known clad materials can be used, including commercially available products. Clad materials are known to be manufactured by methods such as pressure welding, explosive welding, molten metal welding, plating rerolling, and cold spray cladding. Pressure welding is a method in which metals are covalently bonded by applying heat or pressure, and then diffusion bonded by heat treatment to form a bond (adhesion). Pressure welding methods include cold pressure welding, hot pressure welding, and thermal pressure welding. Explosive welding is a method of joining two or more metals using the pressure and heat of a gunpowder explosion. The molten metal welding method involves pouring molten metal into another solid metal. The plating rerolling method is a method of forming an intermetallic bond by electroplating, rolling, and heat treatment. Cold spray cladding is a method of forming a metal coating on a metal substrate by accelerating metal powder to supersonic speed and spraying it in a solid state.

[0064] The clad material of the barrier layer 3 includes at least a first metal layer constituting the surface on the thermally adhesive resin layer 4 side and a second metal layer constituting the surface on the substrate layer 1 side, the first metal layer being an aluminum layer formed of aluminum or an aluminum alloy. Furthermore, in the present disclosure, the clad material constituting the barrier layer 3 exhibits an endothermic peak due to melting at 1000°C or higher in TG-DTA measurement, and does not undergo weight change at the temperature at which the endothermic peak is observed. The electrical storage device packaging material of the present disclosure can exhibit excellent burn resistance and corrosion resistance because the barrier layer 3 is composed of such a specific clad material. The method for measuring the endothermic peak temperature due to melting of the clad material is as follows.

[0065] (Endothermic peak temperature due to melting) The endothermic peak temperature (melting point) due to melting of the clad material is measured by the following measurement method. <Measurement device> TG-DTA

[0066] <Measurement principle> This is a method of obtaining two types of information, thermogravimetry (TG) and differential thermal analysis (DTA), in a single measurement, and measuring the weight change of a sample and endothermic and exothermic reactions. Thermogravimetry (TG) and differential thermal analysis (DTA) are as follows: Thermogravimetry (TG) is a method in which a sample is heated, cooled, or held at a constant temperature, and the weight change is measured as a function of temperature or time. Differential thermal analysis (DTA) is a method in which a sample and a reference material are placed in the same furnace, heated and cooled, and the temperature difference between the two is measured as a function of time or temperature.

[0067] <Measurement method> - Punch out the measurement sample with a punch (or cut with scissors) to a size of φ5 mm. - Place the samples in a sample container, stacking them to a size of φ5 mm x thickness of approximately 1 mm. - Place the container in the device, and increase the furnace temperature from the measurement start temperature to the upper limit of the temperature rise under the specified measurement conditions (below). Measure the thermogravimetry and differential heat during the temperature rise. <Measurement conditions> Measurement sample: Clad material alone Measurement atmosphere: Ar Heating rate: 10°C / min Measurement temperature range: Set from 100°C to 1550°C (temperature range from below the expected melting point of each material to above the expected melting point). - From the measured values ​​of thermogravimetry and differential heat, read the temperature at which the thermogravimetry (weight) does not change and the differential heat analysis shows an endothermic reaction. This value is the endothermic peak temperature (melting point) due to melting.

[0068] From the viewpoint of suitably exerting the effects of the present invention, the endothermic peak temperature (melting point) of the clad material due to melting at 1000°C or higher is preferably about 1300°C or higher, more preferably about 1400°C or higher, and even more preferably about 1500°C or higher, and is preferably about 1800°C or lower, more preferably about 1700°C or lower, and even more preferably about 1600°C or lower, with preferred ranges including about 1300 to 1800°C, about 1300 to 1700°C, about 1300 to 1600°C, about 1400 to 1800°C, about 1400 to 1700°C, about 1400 to 1600°C, about 1500 to 1800°C, about 1500 to 1700°C, and about 1500 to 1600°C. Note that the clad material is composed of two or more types of metals, and two or more endothermic peak temperatures due to melting are observed. In the clad material constituting the barrier layer 3 of the present disclosure, at least one of the two or more endothermic peaks observed has an endothermic peak temperature of 1000°C or higher, and there is no weight change at the temperature at which the endothermic peak is observed.

[0069] The clad material constituting the barrier layer 3 of the present disclosure includes a first metal layer constituting the surface on the thermally adhesive resin layer 4 side and a second metal layer constituting the surface on the substrate layer 1 side. That is, the clad material constituting the barrier layer 3 is a two-layer or more structure including at least a first metal layer and a second metal layer. The clad material may have a two-layer structure including a first metal layer and a second metal layer, a three-layer structure further including a third metal layer positioned between the first metal layer and the second metal layer, a four-layer structure including a third metal layer and a fourth metal layer positioned between the first metal layer and the second metal layer, a five-layer structure including a fourth metal layer, a third metal layer, and a fifth metal layer in this order between the first metal layer and the second metal layer, or a six-layer or more structure. From the viewpoint of optimally achieving the effects of the present disclosure, the clad material may have a two-layer or three-layer structure, or may have four or more layers. A diffusion layer (a portion where the boundary surface between different metals is alloyed by element diffusion and diffusion-bonded) may be present between each metal layer.

[0070] In the present disclosure, the first metal layer constituting the surface of the clad material on the side of the thermally adhesive resin layer 4 is an aluminum layer made of aluminum or an aluminum alloy.

[0071] The composition of the aluminum alloy is not particularly limited. The aluminum alloy preferably contains iron. In an aluminum alloy containing iron, the iron content is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%. By having an iron content of 0.1 mass% or more, an electrical storage device casing material with better formability can be obtained. By having an iron content of 9.0 mass% or less, an electrical storage device casing material with better flexibility can be obtained. Examples of soft aluminum alloys include aluminum alloys 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 also be added as necessary.

[0072] In the present disclosure, the "aluminum" of the aluminum layer refers to aluminum having a purity of 99.00% or more, following the description in "JIS H4000:2017 Aluminum and Aluminum Alloy Plates and Strips," and is also referred to as pure aluminum.

[0073] The thickness of the first metal layer is not particularly limited, and from the viewpoint of more suitably exhibiting the effects of the present disclosure, it is preferably about 40 μm or less, more preferably about 20 μm or less, even more preferably about 10 μm or less, and is preferably about 1 μm or more, more preferably about 3 μm or more, even more preferably about 5 μm or more, with preferred ranges including about 1 to 40 μm, about 1 to 20 μm, about 1 to 10 μm, about 3 to 40 μm, about 3 to 20 μm, about 3 to 10 μm, about 5 to 40 μm, about 5 to 20 μm, and about 5 to 10 μm. If the thickness of the first metal layer is about 1 to 40 μm, the first metal layer remains even after processing, and corrosion resistance is maintained.

[0074] From the viewpoint of optimally achieving the effects of the present invention, the clad material preferably includes a metal layer formed of at least one selected from the group consisting of mild steel, stainless steel, nickel, and titanium. These metal layers are preferred because they have an endothermic peak of 1000°C or higher, exhibit excellent burn-off properties, and have good formability. The metal layer may be a second metal layer. That is, the second metal layer constituting the surface of the clad material facing the substrate layer 1 may be formed of at least one selected from the group consisting of mild steel, stainless steel, nickel, and titanium. Furthermore, the metal layer may be a layer different from the first and second metal layers constituting the surface facing the substrate layer 1 (i.e., a layer located between the first and second metal layers, such as a third metal layer or a fourth metal layer).

[0075] The thickness of the layers other than the first metal layer of the barrier layer 3 is, for example, about 100 μm or less, preferably about 80 μm or less, more preferably about 70 μm or less, and even more preferably about 60 μm or less, and is preferably about 10 μm or more, more preferably about 20 μm or more, and even more preferably about 30 μm or more. Preferred ranges include about 10 to 100 μm, about 10 to 80 μm, about 10 to 70 μm, about 10 to 60 μm, about 20 to 100 μm, about 20 to 80 μm, about 20 to 70 μm, about 20 to 60 μm, about 30 to 100 μm, about 30 to 80 μm, about 30 to 70 μm, and about 30 to 60 μm.

[0076] Mild steel is one of the categories of carbon steel classified by hardness, such as extra-soft steel and hard steel, and is carbon steel containing approximately 0.18 to 0.30 mass% carbon. Stainless steel is a rust-resistant alloy containing iron (Fe) as the main component (50% or more) and 10.5% or more chromium (Cr). Examples of stainless steel include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation-hardened stainless steels. Furthermore, from the viewpoint of providing an exterior material for an electric storage device with excellent formability, the stainless steel is preferably composed of austenitic stainless steel. Specific examples of austenitic stainless steels that constitute stainless steel include SUS304, SUS301, and SUS316L.

[0077] The second metal layer constituting the surface of the clad material on the substrate layer 1 side may be an aluminum layer formed of aluminum or an aluminum alloy. The reason for using aluminum or an aluminum alloy for the second metal layer is that it has an appropriate contact angle and is easy to form a corrosion prevention layer. In this case, the clad material preferably includes a third metal layer between the first and second metal layers, and the third metal layer is preferably a metal layer formed of at least one metal selected from the group consisting of mild steel, stainless steel, nickel, and titanium.

[0078] The thickness of the second metal layer is not particularly limited as long as the effects of the invention of the present disclosure are exhibited. From the viewpoint of more suitably exhibiting the effects of the invention of the present disclosure, the thickness is preferably about 40 μm or less, more preferably about 20 μm or less, and even more preferably about 10 μm or less, and is preferably about 1 μm or more, more preferably about 3 μm or more, and even more preferably about 5 μm or more. Preferred ranges include about 1 to 40 μm, about 1 to 20 μm, about 1 to 10 μm, about 3 to 40 μm, about 3 to 20 μm, about 3 to 10 μm, about 5 to 40 μm, about 5 to 20 μm, and about 5 to 10 μm.

[0079] Furthermore, when the clad material has a third metal layer, the thickness of the third metal layer is not particularly limited, as long as the effects of the invention of the present disclosure are achieved. From the viewpoint of more suitably achieving the effects of the invention of the present disclosure, the thickness is preferably about 80 μm or less, more preferably about 70 μm or less, and even more preferably about 60 μm or less, and is preferably about 10 μm or more, more preferably about 20 μm or more, and even more preferably about 30 μm or more. Preferred ranges include about 10 to 80 μm, about 10 to 70 μm, about 10 to 60 μm, about 20 to 80 μm, about 20 to 70 μm, about 20 to 60 μm, about 30 to 80 μm, about 30 to 70 μm, and about 30 to 60 μm.

[0080] The thickness of the entire clad material constituting the barrier layer 3 is not particularly limited as long as the effects of the invention of the present disclosure are exhibited. From the viewpoint of more suitably exhibiting the effects of the invention of the present disclosure, the thickness is preferably about 140 μm or less, more preferably about 100 μm or less, even more preferably about 80 μm or less, and is preferably about 20 μm or more, more preferably about 30 μm or more, even more preferably about 40 μm or more. Preferred ranges include about 20 to 140 μm, about 20 to 100 μm, about 20 to 80 μm, about 30 to 140 μm, about 30 to 100 μm, about 30 to 80 μm, about 40 to 140 μm, about 40 to 100 μm, and about 40 to 80 μm.

[0081] The surface of the first metal layer of the clad material facing the heat-sealable resin layer 4 has a contact angle measured in accordance with the provisions of JIS R 3257:1999, "Testing Method for Wettability of Substrate Glass Surfaces (Sessential Drop Method)," of preferably 10° or less, more preferably 8° or less, and even more preferably 5° or less, and is, for example, 1° or more, with preferred ranges including approximately 1 to 10°, approximately 1 to 8°, and approximately 1 to 5°. The contact angle is a value measured by the following method. A contact angle of 10° or less has the advantage of making it easier to form a corrosion prevention layer. A contact angle of more than 10° makes it difficult to form a stable film.

[0082] (Wettability (Contact Angle)) The wettability of the inner surface of the barrier layer (surface of the first metal layer) is evaluated (contact angle is measured) by the following measurement method.

[0083] <Equipment used> Device name: Contact angle meter Measurable range: 0 to 180° (resolution 0.01°)

[0084] <Test piece shape> 15 cm x 15 cm (If a test piece of 15 cm x 15 cm size cannot be prepared, any size that allows contact angle measurement may be used.)

[0085] <Measurement environment> Temperature: 23°C Relative humidity: 46%

[0086] <Measurement Method> Measurements are performed in accordance with JIS R 3257:1999, Test Method for Wettability of Glass Substrate Surfaces (Sessential Drop Method). - Set up the equipment. Water used: Purified water (distilled water). Drop amount: 2 μg. Contact angle measurement time after drop: 5 seconds. - Prepare the test specimen and place it on a flat table with the measurement surface facing up. - Place the measuring device on top of the test specimen and press the measurement button. - The specified amount of water (2 μg) is dropped onto the test specimen surface. - After 5 seconds, the contact angle is measured automatically (the formula for calculating the angle is listed below). When the dropped liquid is observed from the side, the contact angles are automatically measured at two locations, one on the left and one on the right. Measurement locations are at least five, and wettability is displayed as the average of the contact angle data from at least five locations. *The radius of the surface of the water droplet in contact with the test specimen is r (mm), and the height from the test specimen to the top of the water droplet is h (mm), and the contact angle (°) is calculated using the following formula: θ=2 tan -1 (h / r)

[0087] Furthermore, the barrier layer 3 preferably has a corrosion-resistant coating at least on the surface on the heat-sealable resin layer 4 side (i.e., the surface on the heat-sealable resin layer side of the first metal layer, which is an aluminum layer formed from aluminum or an aluminum alloy). The barrier layer 3 may have a corrosion-resistant coating on both sides. Here, the term "corrosion-resistant coating" refers to a thin film formed on the surface of the barrier layer by, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment such as applying a coating agent, to provide the barrier layer with corrosion resistance (e.g., acid resistance, alkali resistance, etc.). Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the barrier layer (acid-resistant coating), a coating that improves the alkali resistance of the barrier layer (alkali-resistant coating), or the like. The corrosion-resistant coating may be formed by one type of treatment or a combination of two or more types. Furthermore, the barrier layer may have not only one layer but also multiple layers. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal surface is dissolved using a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may also be included in the definition of chemical conversion treatment. Furthermore, when the barrier layer 3 is provided with a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 3.

[0088] The corrosion-resistant coating prevents delamination between the barrier layer and the base material layer during molding of the electrical storage device packaging material, inhibits dissolution and corrosion of the barrier layer surface due to hydrogen fluoride produced by the reaction between the electrolyte and water, and improves the adhesion (wettability) of the barrier layer surface, thereby preventing delamination between the base material layer and the barrier layer during heat sealing and molding.

[0089] Various corrosion-resistant coatings formed by chemical conversion treatments are known, including mainly corrosion-resistant coatings 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, phosphate chromate treatment, phosphate-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 acetylacetate, 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 paint-on chromate treatment, with paint-on chromate treatment being preferred. This paint-type chromate treatment involves first degreasing at least the surface of the barrier layer facing the heat-fusible resin layer 4 (i.e., the surface of the first metal layer, which is an aluminum layer formed from aluminum or an aluminum alloy, facing the heat-fusible resin layer) using a well-known treatment method such as alkali immersion, electrolytic cleaning, acid pickling, electrolytic pickling, or acid activation, and then coating the degreased surface with a treatment solution mainly composed of a metal phosphate such as chromium (Cr) phosphate, titanium (Ti) phosphate, zirconium (Zr) phosphate, or zinc (Zn) phosphate, or a mixture of these metal salts, or a treatment solution mainly composed of a non-metal phosphate and a mixture of these non-metal salts, or a treatment solution consisting of a mixture of these with a synthetic resin or the like, using a well-known coating method such as roll coating, gravure printing, or immersion, followed by drying. The treatment solution can be, for example, water, alcoholic solvents, hydrocarbon solvents, ketone solvents, ester solvents, or ether solvents, with water being preferred. The resin component used here may be a polymer such as a phenolic resin or an acrylic resin, and may be a chromate treatment using an aminated phenolic 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. The acrylic resin is preferably polyacrylic acid, an acrylic acid-methacrylic acid ester copolymer, an acrylic acid-maleic acid copolymer, an acrylic acid-styrene copolymer, or a derivative thereof such as a sodium salt, an ammonium salt, or an amine salt. Derivatives of polyacrylic acid, such as the ammonium salt, sodium salt, or amine salt of polyacrylic acid, are particularly preferred. In the present disclosure, polyacrylic acid refers to a polymer of acrylic acid. The acrylic resin is also preferably a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride, and is also preferably an ammonium salt, a sodium salt, or an amine salt of a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride. Only one type of acrylic resin may be used, or two or more types may be mixed together.

[0090]

[0091]

[0092]

[0093]

[0094] 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 are the same or different and represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. 1 and R 2 Examples of the alkyl group represented by X and R include linear or branched alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. 1 and R 2Examples of the hydroxyalkyl group represented by the formula (1) include a linear or branched alkyl group 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 hydroxyalkyl group represented by the formula (1) may be the same or different. In the 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 repeating units represented by the 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 comprising repeating units represented by the formula (1) or (3), and then polycondensing the polymer with formaldehyde and an amine (R 1 R 2 NH) to form a functional group (-CHNR 1 R 2 The aminated phenol polymers may be used singly or in combination of two or more.

[0095] Another example of a corrosion-resistant coating 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 a rare earth element oxide sol, an anionic polymer, and a cationic polymer is applied. The coating agent may further contain phosphoric acid or a phosphate salt, and a crosslinking agent for crosslinking the polymer. The rare earth element oxide sol contains rare earth element oxide fine particles (e.g., 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, with cerium oxide being preferred from the perspective of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant coating can be used alone or in combination of two or more. Examples of liquid dispersion media 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, with water being preferred. Preferred examples of cationic polymers include polyethyleneimine, ionic polymer complexes consisting of polyethyleneimine and a polymer having a carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is graft-polymerized onto an acrylic backbone, polyallylamine or its derivatives, and aminated phenols. Preferred anionic polymers include poly(meth)acrylic acid or its salts, or copolymers primarily composed of (meth)acrylic acid or its salts. The crosslinking agent is preferably at least one selected from the group consisting of a compound having a functional group selected from an isocyanate group, a glycidyl group, a carboxyl group, or an oxazoline group, and a silane coupling agent. The phosphoric acid or phosphoric acid salt is preferably a condensed phosphoric acid or a condensed phosphate salt.

[0096] An example of a corrosion-resistant coating is one formed by applying a solution in which fine particles of a metal oxide such as aluminum oxide, titanium oxide, cerium oxide, or tin oxide, or barium sulfate are dispersed in phosphoric acid to the surface of a barrier layer and then baking the coating at 150°C or higher.

[0097] The corrosion-resistant coating may have a laminated structure, if necessary, by further laminating at least one of a cationic polymer and an anionic polymer, such as those mentioned above.

[0098] The composition of the corrosion-resistant film can be analyzed by, for example, time-of-flight secondary ion mass spectrometry.

[0099] 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 a coating-type chromate treatment, the amount of the corrosion-resistant film formed on the surface of the barrier layer 3 is 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 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 in an amount, calculated as phosphorus, of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, per 1000 ml of the aqueous solution.

[0100] The thickness of the corrosion-resistant coating 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 coating and the adhesive strength with the barrier layer and the thermally adhesive resin layer. The thickness of the corrosion-resistant coating can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy. Analysis of the composition of the corrosion-resistant coating using time-of-flight secondary ion mass spectrometry can reveal, for example, the thickness of the corrosion-resistant coating consisting of secondary ions of Ce, P, and O (e.g., Ce2PO4 + , CePO4 - or at least one of ions of Cr, P, and O (e.g., CrPO2 + , CrPO4 - Peaks derived from at least one of the above are detected.

[0101] The chemical conversion treatment is carried out by applying a solution containing a compound used to form a corrosion-resistant coating to the surface of the barrier layer by bar coating, roll coating, gravure coating, immersion, or other methods, and then heating the barrier layer to a temperature of approximately 70 to 200°C. Furthermore, before applying the chemical conversion treatment to the barrier layer, the barrier layer may be subjected to a degreasing treatment using an alkali immersion method, electrolytic cleaning, acid cleaning, electrolytic acid cleaning, or other methods. By performing such a degreasing treatment, the chemical conversion treatment of the surface of the barrier layer can be carried out more efficiently. Furthermore, 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 but also form a fluoride of the metal, which is in a passive state. In such cases, only the degreasing treatment may be performed.

[0102] In the present disclosure, the surface of the first metal layer of the clad material on the side of the heat-sealable resin layer 4 is preferably evaluated as showing no change in the surface condition in the corrosion resistance evaluation described below.

[0103] (Corrosion Resistance) The corrosion resistance of the surface of the first metal layer of the clad material on the side of the thermally adhesive resin layer 4 is evaluated by the following measurement method.

[0104] <Preparation> Solution to be evaluated: Electrolyte 1 mol / L LiPF6 [Solvent EC:DEC:DMC = 1:1:1 = v:v:v] LiPF6; lithium hexafluorophosphate, EC; ethylene carbonate, DEC; diethylene carbonate, DMC; dimethyl carbonate Solvent for wiping: IPA Equipment used: disposable cup etc. (container for taking out electrolyte and IPA), dropper, laboratory paper towel Test piece: 4 cm x 4 cm

[0105] <Measurement environment> Temperature: 24.0℃ Humidity: 40%

[0106] <Measurement method> - Prepare a test piece (4 cm x 4 cm is preferable. If 4 cm x 4 cm is not possible, any piece large enough to drop the electrolyte will be fine) - Place an appropriate amount of electrolyte in a disposable cup or similar - Place the test piece on a flat surface (such as a desk) with the side to be measured facing up - Suck out the electrolyte with a dropper - Use the dropper to drop one drop of electrolyte onto the surface of the test piece (the side to be measured) - Leave it for 8 or 12 hours after dropping - After the specified time has passed, wipe off the electrolyte with a Kimtowel soaked in IPA - Check for changes in the surface condition of the area where the electrolyte was dropped (surface discoloration, rust formation, corrosion, etc.) If there is no change in the surface condition, the corrosion resistance evaluation is OK; if there is a change, the corrosion resistance evaluation is NG.

[0107] [Heat-fusible resin layer 4] In the exterior packaging material for an electricity storage device of the present disclosure, the heat-fusible 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-fusible resin layers being heat-fused together when the electricity storage device is assembled.

[0108] The resin constituting the heat-sealable resin layer 4 is not particularly limited as long as it is heat-sealable, but resins containing a polyolefin skeleton, such as polyolefin and acid-modified polyolefin, are preferred. The presence 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, a peak derived from maleic anhydride is preferably detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wavenumber of 1760 cm. -1 Nearby and wave number 1780 cm -1 A peak derived from maleic anhydride is detected around . When the thermally adhesive resin layer 4 is a layer made 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 such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0109] The heat-sealable resin layer 4 preferably contains a resin containing a polyolefin skeleton as a main component, more preferably a polyolefin as a main component, and even more preferably polypropylene as a main component. Here, "main component" refers to a resin component whose content of the resin components contained in the heat-sealable resin layer 4 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the heat-sealable resin layer 4 contains polypropylene as a main component" means that the polypropylene content of the resin components contained in the heat-sealable resin layer 4 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0110] 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.

[0111] The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefins 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.

[0112] The polyolefin may also be an acid-modified polyolefin. An acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin with an acid component. Examples of the acid-modified polyolefin include the above-mentioned polyolefins, copolymers of the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, and polymers such as crosslinked polyolefins. Examples of the acid component used for acid modification include carboxylic acids or anhydrides thereof, such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0113] 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 onto the cyclic polyolefin. The acid-modified cyclic polyolefin 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.

[0114] Preferred acid-modified polyolefins 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.

[0115] The thermally adhesive resin layer 4 may be formed of one type of resin alone or 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.

[0116] When the thermally adhesive resin layer 4 is laminated with the barrier layer 3, the adhesive layer 5, or the like to produce the exterior packaging material 10 for an electricity storage device of the present disclosure, a pre-formed resin film may be used as the thermally adhesive resin layer 4. Alternatively, the thermally adhesive resin that forms the thermally adhesive resin layer 4 may be formed into a film on the surface of the barrier layer 3, the adhesive layer 5, or the like by extrusion molding, coating, or the like, to form the thermally adhesive resin layer 4 from a resin film.

[0117] Furthermore, the thermally adhesive resin layer 4 may contain a lubricant or the like as necessary. When the thermally adhesive resin layer 4 contains a lubricant, the formability of the electrical storage device packaging material can be improved. The lubricant is not particularly limited, and known lubricants can be used.

[0118] The lubricant is not particularly limited, but preferably an amide-based lubricant is used. 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 types, and a combination of two or more types is preferred.

[0119] In the present disclosure, from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferable that a lubricant be present on at least one of the surface and the interior of the heat-sealable resin layer 4. The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylolamides include methylol stearic acid amide. 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 adipamide, 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 adipamide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamidoethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide.The lubricant may be used alone or in combination of two or more kinds, and it is preferable to use a combination of two or more kinds.

[0120] 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 improving the formability of the exterior material for an electrical storage device, the amount of the lubricant is preferably about 1 mg / m 2 or more, more preferably about 3 mg / m 2 or more, more preferably about 5 mg / m 2 or more, more preferably about 10 mg / m 2 or more, more preferably about 15 mg / m 2 or more, and preferably about 50 mg / m 2 or less, more preferably about 40 mg / m 2 The preferred range is 1 to 50 mg / m 2 Degree, 1-40mg / m 2 Degree, 3-50mg / m 2 Degree, 3-40mg / m 2 degree, 5-50mg / m 2 degree, 5-40mg / m 2 degree, 10-50mg / m 2 degree, 10-40mg / m 2 degree, 15-50mg / m 2 degree, 15-40mg / m 2 The degree of

[0121] When a lubricant is present inside the heat-sealable resin layer 4, the amount thereof is not particularly limited, but from the viewpoint of improving the formability of the packaging material for an electrical storage device, it is preferably about 100 ppm or more, more preferably about 300 ppm or more, and even more preferably about 500 ppm or more, and is preferably about 3000 ppm or less, more preferably about 2000 ppm or less, and preferred ranges include about 100 to 3000 ppm, about 100 to 2000 ppm, about 300 to 3000 ppm, about 300 to 2000 ppm, about 500 to 3000 ppm, and about 500 to 2000 ppm. When two or more types of lubricant are present inside the heat-sealable resin layer 4, the above amount of lubricant is the total amount of lubricant. Furthermore, when two or more types of lubricants are present inside the heat-sealable resin layer 4, the amount of the first type of lubricant present is not particularly limited, but from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferably about 100 ppm or more, more preferably about 300 ppm or more, even more preferably about 500 ppm or more, and is preferably about 3000 ppm or less, more preferably about 2000 ppm or less, and preferred ranges include about 100 to 3000 ppm, about 100 to 2000 ppm, about 300 to 3000 ppm, about 300 to 2000 ppm, about 500 to 3000 ppm, and about 500 to 2000 ppm. The amount of the second type of lubricant present is not particularly limited, but from the viewpoint of improving the formability of the exterior material for an electricity storage device, it is preferably about 50 ppm or more, more preferably about 100 ppm or more, and even more preferably about 200 ppm or more, and is preferably about 1500 ppm or less, more preferably about 1000 ppm or less, and preferred ranges include about 50 to 1500 ppm, about 50 to 1000 ppm, about 100 to 1500 ppm, about 100 to 1000 ppm, about 200 to 1500 ppm, and about 200 to 1000 ppm.

[0122] The lubricant present on the surface of the heat-sealable resin layer 4 may be a lubricant exuded from the resin constituting the heat-sealable resin layer 4, or a lubricant applied to the surface of the heat-sealable resin layer 4.

[0123] The thickness of the heat-sealable resin layer 4 is not particularly limited as long as it functions to heat-seal the heat-sealable resin layers to each other and seal the electricity storage device element, but may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. Note that, 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, 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, more preferably about 35 to 85 μm.

[0124] [Adhesive Layer 5] In the packaging material for an electricity storage device according to the present disclosure, the adhesive layer 5 is a layer that is provided as needed between the barrier layer 3 (or the corrosion-resistant coating) and the heat-sealable resin layer 4 in order to firmly bond them together.

[0125] The adhesive layer 5 is formed of a resin that can bond the barrier layer 3 and the heat-sealable resin layer 4. As the resin used to form the adhesive layer 5, for example, the same adhesive as exemplified for the adhesive layer 2 can be used.

[0126] Furthermore, from the viewpoint of firmly bonding the adhesive layer 5 and the heat-sealable resin layer 4, the resin used to form the adhesive layer 5 preferably contains a polyolefin skeleton, and examples thereof include the polyolefins, acid-modified polyolefins, cyclic polyolefins, and acid-modified cyclic polyolefins exemplified for the heat-sealable resin layer 4 described above. On the other hand, from the viewpoint of firmly bonding the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 preferably contains an acid-modified polyolefin. Examples of acid-modified components include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, as well as anhydrides thereof, acrylic acid, and methacrylic acid. However, from the viewpoint of ease of modification and versatility, maleic anhydride is most preferred. From the viewpoint of the heat resistance of the electrical storage device exterior material, the olefin component is preferably a polypropylene-based resin, and the adhesive layer 5 most preferably contains maleic anhydride-modified polypropylene.

[0127] When the resin used to form the adhesive layer 5 contains a polyolefin skeleton, the adhesive layer 5 preferably contains a resin containing a polyolefin skeleton as a main component, more preferably an acid-modified polyolefin as a main component, and even more preferably an acid-modified polypropylene as a main component. Here, "main component" means that the content of the resin component contained in the adhesive layer 5 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, when the adhesive layer 5 contains acid-modified polypropylene as a main component, it means that the content of acid-modified polypropylene among the resin components contained in the adhesive layer 5 is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0128] The presence 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. Furthermore, the presence of an acid-modified polyolefin in the resin constituting the adhesive layer 5 can be determined by, for example, measuring a maleic anhydride-modified polyolefin by infrared spectroscopy, and finding a wave number of 1760 cm -1 Nearby and wave number 1780 cm -1 A peak derived from maleic anhydride is detected around this point. However, if the degree of acid modification is low, the peak may be small and not be detected. In this case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0129] Furthermore, from the viewpoint of ensuring durability such as heat resistance and resistance to contents of the electrical storage device packaging material, and of ensuring moldability while reducing the thickness, 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 described above.

[0130] 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. A cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group is particularly preferred. The adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. Examples of polyesters include ester resins formed by the reaction of epoxy groups with maleic anhydride groups, and amide ester resins formed by the reaction of oxazoline groups with maleic anhydride groups. If unreacted curing agents such as compounds having an isocyanate group, compounds having an oxazoline group, or epoxy resins remain in the adhesive layer 5, the presence of the unreacted materials can be confirmed by a method selected from the group consisting of infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

[0131] Furthermore, from the viewpoint of further enhancing 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 C—O—C bond. Examples of curing agents having a heterocycle include curing agents having an oxazoline group and curing agents having an epoxy group. Examples of curing agents having a C═N bond include curing agents having an oxazoline group and curing agents having an isocyanate group. Examples of curing agents having a C—O—C bond include curing agents having an oxazoline group and curing agents having an epoxy group. Whether the adhesive layer 5 is a cured product of a resin composition containing such a curing agent can be confirmed 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.

[0132] 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 curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers or nurates thereof, mixtures of these, and copolymers with other polymers. Other examples include adducts, biurets, and isocyanurates.

[0133] 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 %, of 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.

[0134] 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. Examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

[0135] 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.

[0136] Examples of compounds having epoxy groups include epoxy resins. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy groups present in the molecule, and known epoxy resins can be used. The weight-average molecular weight of the epoxy resin is preferably about 50 to 2,000, more preferably about 100 to 1,000, and even more preferably about 200 to 800. In the present disclosure, the weight-average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

[0137] Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F glycidyl 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.

[0138] The proportion 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 %, of 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.

[0139] 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 two-component curing polyurethane.

[0140] 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 %, of 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.

[0141] 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 the 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.

[0142] The adhesive layer 5 may contain a modifier having a carbodiimide group.

[0143] When the adhesive layer 5 is laminated with the barrier layer 3, the heat-sealable resin layer 4, or the like to produce the packaging material for an electricity storage device 10 of the present disclosure, a pre-formed resin film may be used as the adhesive layer 5. Alternatively, the heat-sealable resin that forms the adhesive layer 5 may be formed into a film on the surface of the barrier layer 3, the heat-sealable resin layer 4, or the like by extrusion molding, coating, or the like, to form the adhesive layer 5 from a resin film.

[0144] The thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 5 μm or less. The thickness of the adhesive layer 5 is preferably about 0.1 μm or more, or about 0.5 μm or more. The thickness of the adhesive layer 5 is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, 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, or about 0.5 to 5 μm. More specifically, in the case of adhesives such as those exemplified for 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, more preferably about 1 to 5 μm. Furthermore, when a resin exemplified for the heat-fusible resin layer 4 is used, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When the adhesive layer 5 is an adhesive exemplified for the adhesive layer 2 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed, for example, by applying the resin composition and curing it by heating or the like. When a resin exemplified for the heat-fusible resin layer 4 is used, the heat-fusible resin layer 4 and the adhesive layer 5 can be formed, for example, by extrusion molding.

[0145] [Surface Coating Layer 6] The packaging material for an electricity storage device according to the present disclosure may, if necessary, have a surface coating layer 6 on the substrate layer 1 (the side of the substrate layer 1 opposite to the barrier layer 3) for the purpose of improving at least one of design, electrolyte resistance, scratch resistance, formability, etc. The surface coating layer 6 is a layer located on the outermost layer side of the packaging material for an electricity storage device when an electricity storage device is assembled using the packaging material for an electricity storage device.

[0146] The surface coating layer 6 may be made of, for example, a resin such as polyvinylidene chloride, polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, or phenolic resin, or a modified version of these resins. It may also be a copolymer of these resins or a modified version of the copolymer. It may also be a mixture of these resins. The resin is preferably a curable resin. That is, the surface coating layer 6 is preferably made of a cured product of a resin composition containing a curable resin.

[0147] When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-component curable resin or a two-component curable resin, but is preferably a two-component curable resin. Examples of two-component curable resins include two-component curable polyurethane, two-component curable polyester, and two-component curable epoxy resin. Among these, two-component curable polyurethane is preferred.

[0148] Examples of two-component curing polyurethanes include polyurethanes containing a first component containing a polyol compound and a second component containing an isocyanate compound. Preferred examples of two-component curing polyurethanes include those containing a polyol, such as polyester polyol, polyether polyol, or acrylic polyol, as the first component and an aromatic or aliphatic polyisocyanate as the second component. Examples of polyurethanes include polyurethanes containing an isocyanate compound and a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance. Examples of polyurethanes include polyurethanes containing a polyol compound and a polyurethane compound obtained by reacting a polyol compound with an isocyanate compound in advance. Examples of polyurethanes include polyurethanes obtained by reacting a polyol compound with an isocyanate compound in advance and then curing the polyurethane compound with moisture, such as in the air. Polyol compounds preferably include polyester polyols having hydroxyl groups on the side chains in addition to the terminal hydroxyl groups of the repeating units. Examples of second components 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). Also included are polyfunctional isocyanate-modified compounds of one or more of these diisocyanates. Furthermore, polymers (e.g., trimers) can also be used as polyisocyanate compounds. Examples of such polymers include adducts, biurets, and nurates. It should be noted that an aliphatic isocyanate compound refers to an isocyanate that has an aliphatic group but does not have an aromatic ring, an alicyclic isocyanate compound refers to an isocyanate that has an alicyclic hydrocarbon group, and an aromatic isocyanate compound refers to an isocyanate that has an aromatic ring.The surface coating layer 6 is formed from polyurethane, which provides the electrical storage device packaging material with excellent electrolyte resistance.

[0149] The surface coating layer 6 may contain additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, and pigments, as necessary, in at least one of the surface and interior of the surface coating layer 6, depending on the functionality to be provided to the surface of the surface coating layer 6. Examples of additives include fine particles with an average particle size of approximately 0.5 nm to 5 μm. The average particle size of the additive is the median size measured with a laser diffraction / scattering particle size distribution analyzer.

[0150] The additive may be either inorganic or organic. The shape of the additive is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, and scaly shapes.

[0151] Specific examples of additives include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, 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, high-melting-point nylon, acrylate resin, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. The additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferred from the viewpoints of dispersion stability and cost. The additives may also be subjected to various surface treatments, such as insulation treatment and high-dispersibility treatment.

[0152] The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a resin to form 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.

[0153] In the present disclosure, from the viewpoint of improving the formability of the exterior material for an electrical storage device, it is preferable that a lubricant be present on at least one of the surface and the interior of the surface coating layer 6. The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylolamides include methylol stearic acid amide. 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 adipamide, 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 adipamide, N,N'-dioleyl sebacic acid amide, etc. Specific examples of fatty acid ester amides include stearamidoethyl stearate, etc. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N,N'-distearylisophthalic acid amide.The lubricant may be used alone or in combination of two or more kinds, and it is preferable to use a combination of two or more kinds.

[0154] When a lubricant is present on the surface of the surface coating layer 6, the amount of the lubricant is not particularly limited, but may be, for example, about 3 mg / m 2 or more, preferably about 4 mg / m 2 Above, about 5mg / m 2 The amount of lubricant present on the surface of the surface coating layer 6 is, for example, about 15 mg / m 2 or less, preferably about 14 mg / m 2 Below, about 10mg / m 2 The preferred range of the amount of lubricant present on the surface of the surface coating layer 6 is 3 to 15 mg / m 2 Degree, 3-14mg / m 2 Degree, 3-10mg / m 2 Degree, 4-15mg / m 2 Degree, 4-14mg / m 2 degree, 4-10mg / m 2 degree, 5-15mg / m 2 Degree, 5-14mg / m 2 degree, 5-10mg / m 2 The degree of

[0155] The lubricant present on the surface of the surface coating layer 6 may be a lubricant exuded from the resin that constitutes the surface coating layer 6, or a lubricant applied to the surface of the surface coating layer 6.

[0156] The surface coating layer 6 contains a colorant, which allows the electrical storage device exterior material to be colored. Known colorants such as pigments and dyes can be used as the colorant. Only one type of colorant may be used, or two or more types may be mixed together.

[0157] The type of pigment is not particularly limited, and examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments. Examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments. Other examples include finely powdered mica and fish scale foil.

[0158] Among colorants, carbon black is preferred for making the exterior material for an electricity storage device black, and mica is preferred from the viewpoint of dissipating heat generated from the electricity storage device.

[0159] The average particle size of the pigment is not particularly limited and may be, for example, about 0.03 to 5 μm, and preferably about 0.05 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution analyzer.

[0160] The content of the colorant in the surface coating layer 6 is not particularly limited as long as the packaging material for an electricity storage device is colored, and may be, for example, about 5 to 60 mass %, and preferably about 10 to 40 mass %.

[0161] The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above-mentioned functions as the surface coating layer 6, and may be, for example, about 0.5 to 10 μm, and preferably about 1 to 5 μm.

[0162] 3. Manufacturing Method of the Exterior Material for an Electrical Storage Device The manufacturing method of the exterior material for an electrical storage device is not particularly limited, as long as a laminate in which the layers included in the exterior material for an electrical storage device of the present disclosure are laminated can be obtained, and an example of such a method includes a step of laminating at least the base material layer 1, the barrier layer 3, and the heat-sealable resin layer 4 in this order.

[0163] An example of a manufacturing method for an exterior material for an electricity storage device according to the present disclosure 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 the base layer 1 is laminated thereon, and the adhesive layer 2 is cured.

[0164] Next, a heat-sealable resin layer 4 is laminated on the barrier layer 3 of the laminate A. When the heat-sealable resin layer 4 is laminated directly 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, the adhesive layer 5 and the heat-sealable resin layer 4 may be laminated by, for example, (1) extrusion lamination, (2) thermal lamination, (3) sandwich lamination, or (4) dry lamination. Examples of the (1) extrusion lamination method include a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 on the barrier layer 3 of the laminate A by extrusion (co-extrusion lamination, tandem lamination), etc. Examples of the (2) thermal lamination method include a method of separately forming a laminate in which an adhesive layer 5 and a heat-fusible resin layer 4 are laminated, and laminating this on the barrier layer 3 of the laminate A, or a method of forming a laminate in which an adhesive layer 5 is laminated on the barrier layer 3 of the laminate A, and laminating this on the heat-fusible resin layer 4. Examples of the (3) sandwich lamination method include a method of pouring a molten adhesive layer 5 between the barrier layer 3 of the laminate A and the heat-fusible resin layer 4 that has been previously formed into a sheet, and bonding the laminate A and the heat-fusible resin layer 4 together via the adhesive layer 5. Examples of the (4) dry lamination method include a method of solution-coating an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminate A, drying the adhesive, or baking the adhesive, and laminating the heat-fusible resin layer 4 that has been previously formed into a sheet on the adhesive layer 5.

[0165] When the surface coating layer 6 is provided, the 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 for forming the surface coating layer 6 to the surface of the base layer 1. 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 the surface coating layer 6 is formed 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.

[0166] As described above, a laminate is formed which includes the optional surface coating layer 6 / substrate layer 1 / optional adhesive layer 2 / barrier layer 3 / optional adhesive layer 5 / thermally adhesive resin layer 4 in this order, and in order to strengthen the adhesion of the optional adhesive layer 2 and adhesive layer 5, the laminate may be further subjected to a heat treatment.

[0167] In the packaging material for an electricity storage device, each layer constituting the laminate may be subjected to a surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment, etc. as necessary to improve processability. For example, by subjecting the surface of the base layer 1 opposite to the barrier layer 3 to corona treatment, the printability of ink on the surface of the base layer 1 can be improved.

[0168] 4. Uses of the Electricity Storage Device Exterior Material The electricity storage device exterior material of the present disclosure is used in a package for hermetically housing electricity storage device elements such as a positive electrode, a negative electrode, and an electrolyte. 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 electricity storage device exterior material of the present disclosure. In other words, an electricity storage device can be formed by wrapping an electricity storage device element in the electricity storage device exterior material of the present disclosure.

[0169] Specifically, an electricity storage device using the electricity storage device packaging material is provided by covering an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte with the electricity storage device packaging material of the present disclosure in a state in which metal terminals connected to each of the positive electrode and the negative electrode protrude outward, so that a flange portion (a region where the heat-sealable resin layers contact each other) can be formed around the periphery of the electricity storage device element, and then heat-sealing the heat-sealable resin layers of the flange portion to form a hermetic seal. Note that when an electricity storage device element is housed in a package formed from the electricity storage device packaging material of the present disclosure, the package is formed so that the heat-sealable resin portion of the electricity storage device packaging material of the present disclosure faces inside (the surface that contacts the electricity storage device element). A package may be formed by overlapping two electrical storage device exterior materials with the heat-sealable resin layers facing each other and heat-sealing the peripheral edges of the overlapped electrical storage device exterior materials, or by folding one electrical storage device exterior material over and overlapping the materials and heat-sealing the peripheral edges, as in the example shown in Fig. 5. When the materials are folded over and overlapped, the package may be formed by heat-sealing the sides other than the folded side to form a three-sided seal, as in the example shown in Fig. 5, or by folding over the material so as to form a flange and seal all four sides. When the innermost and outermost layers of the electrical storage device exterior material are heat-sealable resin layers, the package may be formed by heat-sealing the innermost heat-sealable resin layer and the outermost heat-sealable resin layer.

[0170] The electricity storage device element may be sealed with a lid in addition to the electricity storage device exterior material. That is, the electricity storage device exterior material and the lid constitute an exterior (an exterior for an electricity storage device) that seals the electricity storage device element. For example, the electricity storage device element may be housed inside a cylindrically configured electricity storage device exterior material, and the opening may be closed with the lid. In another example, the electricity storage device element connected to the lid may be housed inside a cylindrically configured electricity storage device exterior material that has an opening, and the opening may be closed with the lid. The lid and the electricity storage device exterior material are preferably joined by any means. From the viewpoint of reducing dead space between the electricity storage device element and the electricity storage device exterior material to improve the volumetric energy density of the electricity storage device, the electricity storage device exterior material is preferably wrapped around the electricity storage device element and the lid.

[0171] The lid body can be formed, for example, from a resin molded product, a metal molded product, an exterior material for an electricity storage device, or a combination thereof. In this disclosure, when the lid body is referred to as a resin molded product, this does not include an embodiment in which the lid body is formed solely from a film defined by JIS K6900-1994 [Plastics - Terminology]. When the lid body is a metal molded product, the lid body also functions as a metal terminal, so the metal terminal can be omitted. The lid body may be formed from a resin material and a conductive material.

[0172] Furthermore, a recess for accommodating an electricity storage device element may be formed in the electricity storage device packaging material by deep drawing or bulging molding. As shown in the example in Fig. 5, a recess may be provided in one electricity storage device packaging material and no recess may be provided in the other electricity storage device packaging material, or a recess may also be provided in the other electricity storage device packaging material.

[0173] The exterior material for an electricity storage device of the present disclosure can be suitably used in electricity storage devices such as batteries (including condensers, capacitors, etc.). The exterior material for an electricity storage device of the present disclosure may be used in either primary or secondary batteries, but is preferably used in secondary batteries. The type of secondary battery to which the exterior material for an electricity storage device of the present disclosure is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, semi-solid batteries, quasi-solid batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-metal hydride 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, preferred applications of the exterior material for an electricity storage device of the present disclosure include lithium ion batteries, lithium ion polymer batteries, and all-solid-state batteries.

[0174] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the examples.

[0175] <Production of Exterior Material> (Examples 1-4) Exterior materials for power storage devices having the layered structure shown in Table 1 were produced. A laminated film was prepared as the substrate layer, in which a polyethylene terephthalate film (thickness 12 μm) and a nylon film (thickness 25 μm) were bonded with a two-component curing urethane adhesive (polyester polyol and aromatic isocyanate compound, thickness after curing 3 μm). Furthermore, a clad material having the layered structure shown in Table 1 was prepared as the barrier layer. Furthermore, in the layered structure of the barrier layer (clad material) shown in Table 1, the barrier layer was used such that the second metal layer side (outside) was the substrate layer side and the first metal layer side (inside) was the heat-sealable resin layer side. Using the two-component curing urethane adhesive (polyester polyol and aromatic isocyanate compound), the nylon film side of the substrate layer and the second metal layer side (outside) of the barrier layer were bonded by dry lamination to produce a laminate in which the substrate layer / adhesive layer / barrier layer were laminated in this order.

[0176] Next, maleic anhydride-modified polypropylene (PPa) as an adhesive layer and polypropylene (PP) as a heat-sealable resin layer were co-extruded, and an adhesive layer (PPa 40 μm) / heat-sealable resin layer (PP 40 μm) was laminated on the barrier layer. Next, the resulting laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, each consisting of a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0177] (Examples 5 to 8) Except for using clad materials each having the laminate structure shown in Table 1 as the barrier layer, packaging materials for electricity storage devices each having the laminate structure shown in Table 1 were produced in the same manner as in Examples 1 to 4.

[0178] Examples 9 to 12 Except for using only a nylon film (thickness: 25 μm) as the base material layer, packaging materials for electricity storage devices having the layered structures shown in Table 1 were produced in the same manner as in Examples 1 to 4.

[0179] Examples 13-16 Exterior packaging materials for electricity storage devices were manufactured having the layered structures shown in Table 1. A nylon film (thickness: 25 μm) was prepared as the substrate layer. Clad materials having the layered structures shown in Table 1 were prepared as the barrier layers. In addition, in the layered structure of the barrier layer (clad material) shown in Table 1, the barrier layer was used such that the second metal layer side (outside) was the substrate layer side and the first metal layer side (inside) was the thermally adhesive resin layer side. A two-component curing urethane adhesive (polyester polyol and aromatic isocyanate compound) was used by dry lamination to bond the nylon film side of the substrate layer and the second metal layer side (outside) of the barrier layer, to produce a laminate in which the substrate layer / adhesive layer / barrier layer were laminated in this order.

[0180] Next, the surface of the barrier layer side of the obtained laminate and an unstretched polypropylene film (CPP) as a heat-sealable resin layer were laminated by dry lamination using a two-component curing urethane adhesive (polyester polyol and aromatic isocyanate compound) to form an adhesive layer (thickness after curing: 3 μm) / heat-sealable resin layer (CPP: 40 μm). Next, the obtained laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, each consisting of a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0181] Examples 17-20: Sheathing materials for power storage devices having the layered structures shown in Table 1 were manufactured. A nylon film (thickness: 25 μm) was prepared as the substrate layer. Clad materials having the layered structures shown in Table 1 were prepared as the barrier layers. In addition, in the layered structure of the barrier layer (clad material) shown in Table 1, the barrier layer was used such that the second metal layer side (outside) was the substrate layer side and the first metal layer side (inside) was the heat-sealable resin layer side. A two-component curing urethane adhesive (polyester polyol and aromatic isocyanate compound) was used by dry lamination to bond the nylon film side of the substrate layer and the second metal layer side (outside) of the barrier layer, producing a laminate in which the substrate layer / adhesive layer / barrier layer were laminated in this order.

[0182] Next, the surface of the barrier layer side of the obtained laminate and an unstretched polypropylene film (CPP) as a heat-sealable resin layer were laminated by dry lamination using an adhesive (containing an acid-modified polypropylene and an isocyanate compound) to form an adhesive layer (thickness after curing: 3 μm) / heat-sealable resin layer (CPP: 40 μm). Next, the obtained laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, each consisting of a laminate in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0183] Comparative Example 1-2 Except for using an aluminum alloy foil (JIS H4160:1994 A8021H-O, thickness 60 μm) or a mild steel foil (thickness 60 μm) as the barrier layer, packaging materials for electricity storage devices having the layered structures shown in Table 1 were produced in the same manner as in Example 1-4.

[0184] [Evaluation of Barrier Layer] (Wettability (Contact Angle)) The wettability of the inner surface of the barrier layer (surface of the first metal layer) was evaluated (contact angle was measured) by the following measurement method.

[0185] <Device used> Device name: Contact angle meter Manufacturer: KRUSS Model: MSA Measurable range: 0 to 180° (resolution 0.01°)

[0186] <Test piece shape> Test material: Clad material only Test piece size: 15cm x 15cm

[0187] <Measurement environment> Temperature: 23°C Relative humidity: 46%

[0188] <Measurement method> Measurements are performed in accordance with JIS R 3257:1999 Test method for wettability of glass substrate surfaces (sessile drop method). - Set up the equipment. Water used: Purified water (distilled water) Drop amount: 2 μg Contact angle measurement time after drop: 5 seconds - Prepare the test specimen and place it on a flat table with the measurement surface facing up. - Place the measuring device on top of the test specimen and press the measurement button. - The specified amount of water is dropped onto the test specimen surface. - After 5 seconds, the contact angle is measured automatically (the formula for calculating the angle is given below *). When the dropped liquid is observed from the side, the contact angles at two locations, one on the left and one on the right, are measured automatically. Measurement locations are at least five, and wettability is displayed as the average of the contact angle data from at least five locations. * The radius of the surface of the water droplet in contact with the test specimen is r (mm), and the height from the test specimen to the top of the water droplet is h (mm), and the contact angle (°) is calculated using the following formula: θ = 2 tan -1 (h / r)

[0189] (Corrosion Resistance) The corrosion resistance of the inner surface of the barrier layer (surface of the first metal layer) was evaluated by the following measurement method. <Preparation> - Solution to be evaluated: Electrolyte 1 mol / L LiPF6 [Solvent EC:DEC:DMC=1:1:1=v:v:v] LiPF6: Lithium hexafluorophosphate, EC: Ethylene carbonate, DEC: Diethylene carbonate, DMC: Dimethyl carbonate - Solvent for wiping: IPA - Equipment used: Disposable cup etc. (container for taking out electrolyte and IPA), dropper, Kimtowel - Test sample: Clad material alone - Test piece: 4 cm x 4 cm

[0190] <Measurement environment> Temperature: 24.0℃ Humidity: 40%

[0191] <Measurement method> ・Prepare a test piece (recommended to be at least 4 cm x 4 cm) ・Put an appropriate amount of electrolyte into a disposable cup, etc. ・Place the test piece on a flat surface (desk, etc.) with the side to be measured facing up ・Suck out the electrolyte with a dropper ・Use the dropper to apply one drop of electrolyte to the surface of the test piece (side to be measured) ・After application, leave for the specified time ・After the specified time has passed, wipe off the electrolyte with a Kimtowel soaked in IPA ・Check for changes in the surface condition of the area where the electrolyte was applied (discoloration of the surface, rust formation, corrosion, etc.) If there is no change in the surface condition, the corrosion resistance evaluation is OK; if there is a change, the corrosion resistance evaluation is NG.

[0192] (Endothermic Peak Temperature Due to Melting) The endothermic peak temperature (melting point) due to melting of the barrier layer was measured by the following measurement method. <Measuring Device> TG-DTA (TG-DTA 2000SE Model manufactured by NETZSCH)

[0193] <Measurement principle> This is a method of obtaining two types of information, thermogravimetry (TG) and differential thermal analysis (DTA), in a single measurement, and measuring the weight change of a sample and endothermic and exothermic reactions. Thermogravimetry (TG) and differential thermal analysis (DTA) are as follows: Thermogravimetry (TG) is a method in which a sample is heated, cooled, or held at a constant temperature, and the weight change is measured as a function of temperature or time. Differential thermal analysis (DTA) is a method in which a sample and a reference material are placed in the same furnace, heated and cooled, and the temperature difference between the two is measured as a function of time or temperature.

[0194] <Measurement Method> - Prepare a single layer of clad material as the measurement sample. - Punch out the measurement sample with a punch (or cut it with scissors) to a size of φ5 mm. - Place the samples in a sample container, stacked so that they are approximately φ5 mm x 1 mm thick. - Place the container in the device, and increase the furnace temperature from the measurement start temperature to the upper limit of the temperature rise under the specified measurement conditions (below). Measure the thermogravimetry and differential heat during the temperature rise. <Measurement Conditions> Measurement atmosphere: Ar Heating rate: 10°C / min Measurement temperature range: 100°C to 1550°C (temperature range from below the expected melting point of each material to above the expected melting point). - From the measured values ​​of thermogravimetry and differential heat, read the temperature at which the thermogravimetry (weight) does not change and the differential heat analysis shows an endothermic reaction. This value is the endothermic peak temperature (melting point) due to melting.

[0195] It was confirmed that the barrier layers of Examples 1 to 20 did not experience any weight change at the endothermic peak temperature due to melting.

[0196] <Evaluation of Burn-off Resistance of Barrier Layer> Based on the following measurement method, the clad material was placed in a furnace at a temperature (900°C) higher than the melting point of the aluminum alloy, and after a certain period of time, it was confirmed whether the shape was maintained. If the shape was maintained, it was judged as grade A, and if the shape was not maintained, it was judged as grade C. Since the clad material was graded A, it was evaluated as having excellent burn-off resistance.

[0197] <Measurement method> ・Sample state: Clad material alone ・Sample shape: 30mm x 30mm ・Sample insertion method: Place the sample in the crucible, and then place the crucible in the furnace ・Retention time: 6 hours ・Sample confirmation method: Visual inspection ・Judgment method: If the shape remains, it is graded as A, and if not, it is graded as C ・Measurement method: Prepare an electric furnace heated to 900°C. Open the door of the electric furnace, place the crucible containing the sample, and close the door. ・Open the door after 6 hours, remove the crucible, and visually confirm the shape

[0198]

[0199] *In Table 1, the wettability (contact angle (°)) and corrosion resistance were evaluated for the inner surface of the barrier layer (surface of the first metal layer). Also, in Table 1, PET stands for polyethylene terephthalate, DL stands for an adhesive layer or bond layer formed by dry lamination, Ny stands for nylon, ALM stands for aluminum, PPa stands for maleic anhydride-modified polypropylene, and PP stands for polypropylene. The numbers in parentheses for the laminate structure are the layer thicknesses (μm).

[0200] The electrical storage device packaging materials of Examples 1 to 20 each comprise a laminate including at least a barrier layer and a heat-sealable resin layer in this order, the barrier layer being comprised of a clad material, the clad material including at least a first metal layer constituting the surface on the heat-sealable resin layer side and a second metal layer constituting the surface opposite to the heat-sealable resin layer side, the first metal layer being an aluminum layer formed of aluminum or an aluminum alloy, and in differential thermal analysis measurement by TG-DTA, the clad material exhibits an endothermic peak due to melting at 1000°C or higher, and there is no weight change at the temperature at which the endothermic peak is observed. It can be seen that the electrical storage device packaging materials of Examples 1 to 20 have fire resistance and excellent corrosion resistance.

[0201] As described above, the present disclosure provides the following aspects of the invention. Item 1. A packaging material for an electricity storage device, comprising a laminate including at least a barrier layer and a heat-sealable resin layer in this order, wherein the barrier layer is composed of a clad material, and the clad material includes at least a first metal layer constituting a surface on the heat-sealable resin layer side and a second metal layer constituting a surface opposite to the heat-sealable resin layer side, wherein the first metal layer is an aluminum layer formed of aluminum or an aluminum alloy, and wherein the clad material exhibits an endothermic peak due to melting at 1000°C or higher in differential thermal analysis measurement by TG-DTA, and exhibits no weight change at the temperature at which the endothermic peak is observed. Item 2. The packaging material for an electricity storage device according to Item 1, wherein the clad material includes a metal layer formed of at least one metal selected from the group consisting of mild steel, stainless steel, nickel, and titanium. Item 3. The packaging material for an electricity storage device according to Item 2, wherein the thickness of the layer of the barrier layer other than the first metal layer is 100 μm or less. Item 4. The packaging material for an electricity storage device according to Item 2 or 3, wherein the second metal layer of the clad material is a metal layer formed from at least one selected from the group consisting of mild steel, stainless steel, nickel, and titanium. Item 5. The packaging material for an electricity storage device according to any one of Items 1 to 4, wherein the thickness of the first metal layer is 40 μm or less. Item 6. The packaging material for an electricity storage device according to any one of Items 1 to 5, wherein the clad material has a three-layer structure. Item 7. The packaging material for an electricity storage device according to any one of Items 1 to 6, wherein the second metal layer of the clad material is an aluminum layer formed from aluminum or an aluminum alloy. Item 8. The packaging material for an electricity storage device according to any one of Items 1 to 7, wherein a third metal layer located between the first metal layer and the second metal layer of the clad material is a metal layer formed from at least one selected from the group consisting of mild steel, stainless steel, nickel, and titanium. Item 9. Item 9. The electrical storage device packaging material according to any one of items 1 to 8, wherein the thickness of a third metal layer located between the first metal layer and the second metal layer of the clad material is 80 μm or less.Item 10. The packaging material for an electricity storage device according to any one of Items 1 to 9, wherein a surface of the first metal layer facing the heat-sealable resin layer has a contact angle of 10° or less, measured in accordance with JIS R 3257:1999 "Testing method for wettability of substrate glass surfaces (sessile drop method)". Item 11. The packaging material for an electricity storage device according to any one of Items 1 to 10, wherein the clad material exhibits an endothermic peak due to melting in a temperature range of 1000°C to 1800°C in differential thermal analysis (TG-DTA) measurement, and exhibits no weight change at the temperature at which the endothermic peak is observed. Item 12. The packaging material for an electricity storage device according to any one of Items 1 to 11, wherein a surface of the first metal layer facing the heat-sealable resin layer has a contact angle of 1° or more and 10° or less, measured in accordance with JIS R 3257:1999 "Testing method for wettability of substrate glass surfaces (sessile drop method)". Item 13. 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 packaging material for an electricity storage device according to any one of Items 1 to 12. Item 14. A method for producing an exterior material for an electricity storage device, comprising a step of laminating at least a barrier layer and a heat-sealable resin layer in this order to obtain a laminate, wherein the barrier layer is made of a clad material, the clad material includes at least a first metal layer that forms a surface on the heat-sealable resin layer side and a second metal layer that forms a surface on the opposite side to the heat-sealable resin layer side, the first metal layer is an aluminum layer made of aluminum or an aluminum alloy, and the clad material exhibits an endothermic peak due to melting at 1000°C or higher in TG-DTA measurement, and does not experience a weight change at the temperature at which the endothermic peak is observed.

[0202] REFERENCE SIGNS LIST 1 base material layer 2 adhesive layer 3 barrier layer 4 heat-sealable resin layer 5 adhesive layer 6 surface coating layer 10 packaging material for electricity storage device

Claims

1. An exterior material for an electricity storage device, which is composed of a laminate having at least a barrier layer and a heat-sealable resin layer in this order, wherein the barrier layer is composed of a clad material, and the clad material includes at least a first metal layer that forms the surface on the heat-sealable resin layer side and a second metal layer that forms the surface on the opposite side to the heat-sealable resin layer side, and the first metal layer is an aluminum layer made of aluminum or an aluminum alloy, and in differential thermal analysis measurement by TG-DTA, the clad material exhibits an endothermic peak due to melting at 1000°C or higher, and does not experience a weight change at the temperature at which the endothermic peak is observed.

2. The exterior packaging material for an electricity storage device according to claim 1, wherein the clad material includes a metal layer formed of at least one selected from the group consisting of mild steel, stainless steel, nickel, and titanium.

3. The packaging material for an electricity storage device according to claim 2, wherein the thickness of the layers of the barrier layer other than the first metal layer is 100 μm or less.

4. An exterior material for an electricity storage device according to claim 2 or 3, wherein the second metal layer of the clad material is a metal layer formed from at least one selected from the group consisting of mild steel, stainless steel, nickel, and titanium.

5. The packaging material for an electricity storage device according to claim 1 or 2, wherein the thickness of the first metal layer is 40 μm or less.

6. The packaging material for an electricity storage device according to claim 1 or 2, wherein the clad material has a three-layer structure.

7. The packaging material for an electricity storage device according to claim 6, wherein the second metal layer of the clad material is an aluminum layer formed from aluminum or an aluminum alloy.

8. The exterior packaging material for an electricity storage device according to claim 6, wherein a third metal layer located between the first metal layer and the second metal layer of the clad material is a metal layer formed from at least one metal selected from the group consisting of mild steel, stainless steel, nickel, and titanium.

9. The exterior packaging material for an electricity storage device according to claim 7, wherein the thickness of a third metal layer located between the first metal layer and the second metal layer of the clad material is 80 μm or less.

10. The exterior packaging material for an electricity storage device according to claim 1 or 2, wherein the surface of the first metal layer facing the heat-sealable resin layer has a contact angle of 10° or less, measured in accordance with the provisions of JIS R 3257:1999 "Test method for wettability of substrate glass surfaces (sessile drop method)." 11. The exterior packaging material for an electricity storage device according to claim 1 or 2, wherein, in differential thermal analysis measurement by TG-DTA, an endothermic peak due to melting is observed in the range of 1000°C to 1800°C, and the clad material does not change in weight at the temperature at which the endothermic peak is observed.

12. The exterior packaging material for an electricity storage device according to claim 1 or 2, wherein the surface of the first metal layer facing the heat-sealable resin layer has a contact angle of 1° or more and 10° or less, measured in accordance with the provisions of JIS R 3257:1999 "Test method for wettability of substrate glass surfaces (sessile drop method)." 13. An electricity storage device, in which an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the exterior packaging material for an electricity storage device according to claim 1 or 2.

14. A method for manufacturing an exterior material for an electricity storage device, comprising a step of laminating at least a barrier layer and a heat-sealable resin layer in this order to obtain a laminate, wherein the barrier layer is made of a clad material, the clad material includes at least a first metal layer that forms the surface on the heat-sealable resin layer side and a second metal layer that forms the surface opposite to the heat-sealable resin layer side, the first metal layer is an aluminum layer made of aluminum or an aluminum alloy, and the clad material exhibits an endothermic peak due to melting at 1000°C or higher in TG-DTA measurement, and does not experience a weight change at the temperature at which the endothermic peak is observed.

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