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

Abstract

To provide a technique for suppressing curling by molding of an exterior material for a power storage device.SOLUTION: An exterior material for a power storage device is composed of a laminate having at least a base material layer, a barrier layer and a heat-fusible resin layer in this order, wherein the laminate has a gradient of a stress-strain curve between two strain points at a tensile strain of 1% and a tensile strain of 5% in an MD direction of 700 MPa or less.

Description

[Technical Field]

[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. [Background technology]

[0002] Various types of electricity storage devices have been developed, but in all of them, packaging materials (exterior materials) are essential components for sealing the 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, in recent years, a film-like packaging material in which a substrate / aluminum alloy foil layer / thermally adhesive 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 electrolyte 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. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-287971 Summary of the Invention [Problem to be solved by the invention]

[0007] From the perspective of further increasing the energy density of electricity storage devices, it is necessary to form deeper recesses in film-like exterior materials by molding.

[0008] However, the inventors of the present disclosure have conducted research and found that when attempting to form a deeper recess in the exterior material, the peripheral edge of the recess may curl (bend) during molding, which may hinder the placement of the energy storage device elements and the heat fusion of the heat-sealable resin layer, thereby reducing the production efficiency of the energy storage device.

[0009] For example, in electricity storage devices used in small equipment such as personal computers, cameras, and mobile phones, it is necessary to form deep recesses with small areas in thin exterior materials, which can result in significant curling due to molding.Furthermore, in medium- or large-sized electricity storage devices such as those for vehicle installation or stationary use, the size of the exterior materials is large, so curling also becomes significant, and the curling has a significant effect on the production efficiency of the electricity storage devices.

[0010] Under these circumstances, a main object of the present disclosure is to provide a technique for suppressing curling due to molding of an exterior material for an electricity storage device. [Means for solving the problem]

[0011] The inventors of the present disclosure conducted extensive research to solve the above-mentioned problems. They evaluated the tensile modulus (the slope of the stress / strain curve corresponding to two points of strain, 0.05% and 0.25%) of electrical storage device exterior materials according to the provisions of JIS K 7161-1:2014 (the same applies to ISO 527-1:2012), which has been commonly used to evaluate the tensile properties of plastics, and thereby investigated the relationship between the curl due to molding (hereinafter sometimes referred to as "molding curl") and the tensile modulus of various fabricated exterior materials. However, when deep recesses were formed in the electrical storage device exterior material, no clear correlation was found between the molding curl and the tensile modulus. The inventors of the present disclosure considered this to be due to the fact that electrical storage device exterior materials are laminates including a substrate layer, a barrier layer, a heat-sealable resin layer, and the like, and are not simply plastic films, and therefore conventional evaluation methods cannot be applied. They therefore conducted further research into the relationship between the molding curl and tensile properties. The inventors of the present disclosure then investigated the relationship between the slope of the stress / strain curve at a stage where the strain is greater than the tensile modulus specified in JIS K 7161-1:2014 and the curl that occurs when an electrical storage device exterior material is deeply formed. They found that, with conventional electrical storage device exterior materials, the slope of the stress / strain curve corresponding to the two points of 1% and 5% tensile strain in a specific direction is high. They also found that by setting the slope of the stress / strain curve corresponding to the two points of 1% and 5% tensile strain in a specific direction to a predetermined value or less, the curl that occurs when an electrical storage device exterior material is deeply formed can be suitably suppressed.

[0012] The present disclosure has been completed based on these findings and further investigations. That is, the present disclosure provides the inventions of the following aspects. The laminate is composed of at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, The laminate is an exterior material for an electricity storage device, in which the gradient of the stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the MD direction is 700 MPa or less. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to provide a technique for suppressing curling due to molding of an exterior material for an electricity storage device. Furthermore, according to the present disclosure, it is also possible to provide a method for manufacturing an exterior material for an electricity storage device, and an electricity storage device. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior packaging material for an electricity storage device according to the present disclosure. [Figure 2] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior packaging material for an electricity storage device according to the present disclosure. [Figure 3] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior packaging material for an electricity storage device according to the present disclosure. [Figure 4] 1 is a schematic diagram showing an example of a cross-sectional structure of an exterior packaging material for an electricity storage device according to the present disclosure. [Figure 5] FIG. 2 is a schematic diagram illustrating a method for evaluating curling due to molding of an exterior material for an electricity storage device. [Figure 6] FIG. 2 is a schematic diagram illustrating a method for evaluating curling due to molding of an exterior material for an electricity storage device. [Figure 7] 1 is a schematic plan view of a package formed from an exterior packaging material for an electricity storage device according to the present disclosure. [Figure 8] FIG. 8 is a schematic cross-sectional view taken along line AA' in FIG. [Figure 9] 1 is a schematic plan view of a package formed from an exterior packaging material for an electricity storage device according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] The electrical storage device packaging material of the present disclosure is composed of a laminate including at least a base material layer, a barrier layer, and a thermally adhesive resin layer in this order, and is characterized in that the slope of a stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the MD direction is 700 MPa or less. By having this configuration, the electrical storage device packaging material of the present disclosure can suitably suppress curling during molding of the electrical storage device packaging material.

[0016] The packaging material for an electricity storage device of the present disclosure will be described in detail below. In this specification, a numerical range indicated by "to" means "not less than" or "not more than." For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less.

[0017] 1.Layer structure and physical properties of exterior materials for energy storage devices As shown in Figures 1 to 4, for example, an electrical storage device packaging material 10 of 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 electrical storage device packaging material 10, the base material layer 1 is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. When assembling an electrical storage device using the electrical storage device packaging material 10 and an electrical storage device element, the electrical storage device element is housed in a space formed by heat-sealing the peripheral portions of the electrical storage device packaging material 10 with the heat-sealable resin layers 4 facing each other.

[0018] 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 for an electricity storage device may have an adhesive layer 5 between the barrier layer 3 and the heat-sealable resin layer 4, if necessary, for the purpose of increasing the adhesion between these layers. 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.

[0019] The thickness of the laminate constituting the electrical storage device packaging material 10 is not particularly limited, but the upper limit is preferably about 180 μm or less, about 155 μm or less, or about 120 μm or less from the viewpoint of cost reduction, improving energy density, etc., and the lower limit is preferably about 35 μm or more, about 45 μm or more, or about 60 μm or more from the viewpoint of maintaining the function of the electrical storage device packaging material to protect the electrical storage device elements, and preferred ranges include, for example, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 180 μm, about 60 to 155 μm, or about 60 to 120 μm.

[0020] In the packaging material for an electricity storage device of the present disclosure, the ratio of the total thickness of the base material layer 1, the adhesive layer 2 (if provided as needed), the barrier layer 3, the adhesive layer 5 (if provided as needed), the heat-sealable resin layer 4, and the surface coating layer 6 (if provided as needed) to the thickness (total thickness) of the laminate constituting the packaging material for an electricity storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the packaging material for an electricity storage device 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 packaging material for an electricity storage device 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, even when the packaging material for an electricity storage device of the present disclosure includes 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 packaging material for an electricity storage device 10 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0021] In the packaging material for an electricity storage device, the MD (Machine Direction) and TD (Transverse Direction) of the barrier layer 3 described below can usually be determined during the manufacturing process. For example, when the barrier layer 3 is made of an aluminum alloy foil, linear streaks called rolling marks are formed on the surface of the aluminum alloy foil in the rolling direction (RD) of the aluminum alloy foil. Since the rolling marks extend along the rolling direction, the rolling direction of the aluminum alloy foil can be determined by observing the surface of the aluminum alloy foil. Furthermore, during the manufacturing process of a laminate, the MD of the laminate usually coincides with the RD of the aluminum alloy foil, so the MD of the laminate can be identified by observing the surface of the aluminum alloy foil and identifying the rolling direction (RD) of the aluminum alloy foil. Furthermore, since the TD of the laminate is perpendicular to the MD of the laminate, the TD of the laminate can also be identified.

[0022] The laminate constituting the packaging material 10 for an electricity storage device of the present disclosure has a slope X of a stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the MD direction. MD In order to more effectively suppress forming curl when the forming depth is increased, the slope X of the stress-strain curve is set to a predetermined value of 700 MPa or less. MD The upper limit of the stress-strain curve is, for example, about 690 MPa or less, preferably about 600 MPa or less, more preferably about 550 MPa or less, and even more preferably about 510 MPa or less. MDThe lower limit of the pressure is preferably about 290 MPa or more, more preferably about 350 MPa or more, even more preferably about 380 MPa or more, even more preferably about 430 MPa or more, and even more preferably about 450 MPa or more. Preferred ranges include about 290 to 700 MPa, about 290 to 690 MPa, about 290 to 600 MPa, about 290 to 550 MPa, about 290 to 510 MPa, about 350 to 700 MPa, about 350 to 690 MPa, about 350 to 600 MPa, about 350 to 550 MPa, about 350 to 510 MPa, about 380 to 700 MPa, about 380 to 690 MPa, and about 380 to 750 MPa. Examples include about 600 MPa, about 380 to 550 MPa, about 380 to 510 MPa, about 430 to 700 MPa, about 430 to 690 MPa, about 430 to 600 MPa, about 430 to 550 MPa, about 430 to 510 MPa, about 450 to 700 MPa, about 450 to 690 MPa, about 450 to 600 MPa, about 450 to 550 MPa, and about 450 to 510 MPa.

[0023] In addition, the packaging material 10 for an electricity storage device according to the present disclosure has a slope X of a stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the TD direction. TD Although there are no particular limitations on the slope X of the stress-strain curve, from the viewpoint of more effectively suppressing molding curl when the molding depth is increased, the upper limit is preferably 630 MPa or less, more preferably about 550 MPa or less, even more preferably about 500 MPa or less, and even more preferably about 440 MPa or less. TDThe lower limit is preferably 240 MPa or higher, more preferably about 300 MPa or higher, even more preferably about 330 MPa or higher, and even more preferably about 350 MPa or higher. Preferred ranges include about 240 to 630 MPa, about 240 to 550 MPa, about 240 to 500 MPa, about 240 to 440 MPa, about 300 to 630 MPa, about 300 to 550 MPa, about 300 to 500 MPa, about 300 to 440 MPa, about 330 to 630 MPa, about 330 to 550 MPa, about 330 to 500 MPa, about 330 to 440 MPa, about 350 to 630 MPa, about 350 to 550 MPa, about 350 to 500 MPa, and about 350 to 440 MPa.

[0024] Furthermore, in the laminate constituting the electrical storage device packaging material 10 of the present disclosure, the absolute value of the difference between the slope of the stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the MD direction and the slope of the stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the TD direction is preferably about 118 MPa or less, more preferably about 85 MPa or less, even more preferably about 80 MPa or less, even more preferably about 65 MPa or less, and even more preferably about 50 MPa or less. The lower limit of this difference is, for example, 0 MPa, 5 MPa, 10 MPa, 20 MPa, etc. Preferred ranges include about 0 to 118 MPa, about 0 to 85 MPa, about 0 to 80 MPa, about 0 to 65 MPa, about 0 to 50 MPa, about 5 to 118 MPa, about 5 to 85 MPa, about 5 to 80 MPa, about 5 to 65 MPa, about 5 to 50 MPa, about 10 to 118 MPa, about 10 to 85 MPa, about 10 to 80 MPa, about 10 to 65 MPa, about 10 to 50 MPa, about 20 to 118 MPa, about 20 to 85 MPa, about 20 to 80 MPa, about 20 to 65 MPa, and about 20 to 50 MPa.

[0025] The slope X of the stress-strain curve of the exterior packaging material 10 for an electricity storage device according to the present disclosure MD , X TDare values ​​measured by the following method. The slope of the stress-strain curve corresponding to two strain points at 1% tensile strain and 5% tensile strain in the MD and TD directions of the electrical storage device packaging material is measured using a tensile tester. Note that conditions other than the above-mentioned range of tensile strain (measurement conditions and calculation methods other than the tensile strain range) are measured in accordance with the provisions of JIS K 7161-1:2014. The sample is rectangular, 15 mm wide and 50 mm or longer, with a gauge length of 30 mm, a pulling rate of 50 mm / min, and a test environment of 23°C. The slope of the stress-strain curve at each strain is calculated using the least-squares regression method. Note that if it is not possible to prepare a sample of the above shape due to circumstances such as the small size of the electrical storage device packaging material, it is also possible to measure it in a size that is measurable.

[0026] When the electricity storage device of the present disclosure is produced using the exterior packaging material 10 for an electricity storage device of the present disclosure, if the storage section for the electricity storage device element of the package formed using the exterior packaging material 10 for an electricity storage device of the present disclosure has a rectangular shape in plan view, it is preferable that the long side direction of the rectangular shape in plan view of the storage section corresponds to the TD direction of the exterior packaging material 10 for an electricity storage device. MD The value of X TD When the value is higher than the value of , molding with TD as the long side (see FIG. 9) makes it possible to manufacture an electricity storage device in which molding curl is more suitably suppressed. In the case of a packaging material for an electricity storage device according to the present disclosure, which is composed of a laminate including at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, tension is applied in the MD direction in the manufacturing process, and therefore, X MD The value of X TD tends to be higher than the value of

[0027] 7 and 8, in a package 100 formed from the exterior packaging material 10 for an electricity storage device according to the present disclosure, the storage section 100a for the electricity storage device element is produced by cold-forming the exterior packaging material 10 for an electricity storage device using a molding die. The molding die is usually rectangular in plan view, and the storage section 100a is also usually rectangular in plan view. The rectangular shape may have right-angled corners or may have rounded corners instead of right angles.

[0028] In order to set the slope of the stress-strain curve of the electrical storage device packaging material to the above value, for example, the materials, thicknesses, and various physical properties of each layer constituting the electrical storage device packaging material, such as the base material layer 1, barrier layer 3, heat-sealable resin layer 4, and further the adhesive layer 2, adhesive layer 5, and surface coating layer 6, are adjusted. Furthermore, for example, when the base material layer 1 is formed from a resin film, it is preferable to adjust manufacturing conditions such as the stretching method, stretching ratio, stretching speed, cooling temperature, and heat setting temperature of the resin film. For example, when the barrier layer is formed from a metal foil, it is also preferable to adjust manufacturing conditions such as the stretching method, stretching ratio, stretching speed, cooling temperature, and heat setting temperature of the metal foil. Furthermore, since these factors also affect the softness of the heat-sealable resin layer 4, it is also preferable to adjust the melt mass-flow rate (MFR), melting point, softening point, glass transition point, film-forming method, film-forming temperature, film-forming speed, and the type and amount of additives such as elastomers of the resin constituting the heat-sealable resin layer 4. These adjustments can be made based on known techniques.

[0029] 2. Each layer that forms the exterior material for the energy storage device [Base material layer 1] In the present disclosure, the substrate layer 1 is a layer provided for the purpose of allowing the packaging material for an electricity storage device to function as a substrate, etc. The substrate layer 1 is located on the outer layer side of the packaging material for an electricity storage device.

[0030] There are no particular limitations on the material forming the base layer 1, as long as it functions as a base, i.e., has at least insulating properties. The base layer 1 can be formed using, for example, a resin, which may contain additives described below.

[0031] When the base layer 1 is formed of a resin, the base layer 1 may be, for example, a resin film formed of a resin, or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially stretched films and biaxially stretched films, with biaxially stretched films being preferred. Examples of stretching methods for forming biaxially stretched films include sequential biaxial stretching, inflation, and simultaneous biaxial stretching. Examples of methods for applying a resin include roll coating, gravure coating, and extrusion coating.

[0032] 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 or a modified version of the copolymer. Furthermore, it may also be a mixture of these resins.

[0033] Of these, preferred resins for forming the base layer 1 include polyester and polyamide.

[0034] 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.

[0035] 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), which contain 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 singly or in combination of two or more.

[0036] The base layer 1 preferably includes at least one of a polyester film, a polyamide film, and a polyolefin film, preferably includes at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, more preferably includes at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film, and even more preferably includes at least one of a biaxially oriented polyethylene terephthalate film, a biaxially oriented polybutylene terephthalate film, a biaxially oriented nylon film, and a biaxially oriented polypropylene film.

[0037] The base layer 1 may be a single layer, or may be composed of two or more layers. When the base layer 1 is composed of a single layer, the base layer 1 is preferably composed of a single layer of the above-mentioned polyamide film or polyester film. When the base layer 1 is composed of two or more layers, the base layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or 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 layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base layer 1.

[0038] Specific examples of laminates of two or more resin films in the base layer 1 include laminates of polyester film and nylon film, laminates of two or more nylon films, and laminates of two or more polyester films. Preferably, laminates of stretched nylon film and stretched polyester film, laminates of two or more stretched nylon films, and laminates of two or more stretched polyester films are preferred. For example, when the base layer 1 is a laminate of two resin films, a laminate of polyester resin film and polyester resin film, a laminate of polyamide resin film and polyamide resin film, or a laminate of polyester resin film and polyamide resin film is preferred. A laminate of polyethylene terephthalate film and polyethylene terephthalate film, a laminate of nylon film and nylon film, or a laminate of polyethylene terephthalate film and nylon film is more preferred. Furthermore, when the base layer 1 is a laminate of two or more resin films, it is preferred that the polyester resin film be located as the outermost layer of the base layer 1, because polyester resins are less likely to discolor when an electrolyte solution adheres to their surface.

[0039] 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 the same adhesives as 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 by dry lamination, a polyurethane adhesive is preferably used 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 the same adhesives as 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.

[0040] Furthermore, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present on at least one of the surface and the interior of the base material layer 1. Only one type of additive may be used, or two or more types may be mixed and used.

[0041] 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 the surface of the base 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, and N,N'-distearyl sebacic acid amide. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide. Specific examples of fatty acid ester amides include stearamidoethyl stearate. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N,N'-distearyl isophthalic acid amide, etc. The lubricants may be used singly or in combination of two or more.

[0042] When a lubricant is present on the surface of the base layer 1, the amount of the lubricant is not particularly limited, but is preferably about 3 mg / m 2 or more, more preferably 4 to 15 mg / m 2 approximately, more preferably 5 to 14 mg / m 2 The degree of

[0043] The lubricant present on the surface of the base layer 1 may be a lubricant exuded from the resin that constitutes the base layer 1, or a lubricant applied to the surface of the base layer 1.

[0044] The thickness of the base layer 1 is not particularly limited as long as it functions as a base, but may be, for example, about 3 to 50 μm, and preferably about 10 to 35 μm. When the base layer 1 is a laminate of two or more resin films, the thickness of each resin film constituting each layer may be, for example, about 2 to 35 μm, and preferably about 2 to 25 μm.

[0045] [Coat layer] The packaging material for an electricity storage device according to the present disclosure may, if necessary, have a coating layer (not shown) on the substrate layer 1 (the side of the substrate layer 1 opposite the barrier layer 3) for the purpose of improving printability, formability, and the like. The coating layer is provided so as to be in contact with the substrate layer 1. The thickness of the coating layer is not particularly limited as long as it exhibits the above-described function of the coating layer, and may be, for example, about 0.01 to 0.40 μm, preferably about 0.01 to 0.30 μm, and more preferably about 0.1 to 0.30 μm. A thickness of 0.01 μm or more allows a layer of uniform thickness to be formed on the substrate layer 1. As a result, the printing property of the packaging material for an electricity storage device according to the present disclosure does not become uneven, enabling uniform printing, and uniform formability can be obtained.

[0046] Examples of resins that can form the coating layer include various synthetic resins such as polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, polyolefin, acid-modified polyolefin, polyester, epoxy resin, phenolic resin, fluororesin, cellulose ester, polyurethane, acrylic resin, polyamide, etc. Among these, polyurethane, polyester, and acrylic resin are preferred.

[0047] The coating layer may contain lubricants or additives as needed to improve slipperiness. Examples of lubricants include the same lubricants as those mentioned above. Examples of additives include the same additives as those exemplified for the surface coating layer 6 described below. The content and particle size of these lubricants and additives are adjusted appropriately according to the thickness of the coating layer.

[0048] Furthermore, the packaging material for an electricity storage device of the present disclosure may have a coating layer (not shown) on one side (the barrier layer 3 side of the substrate layer 1 or the side opposite to the barrier layer 3 of the substrate layer 1) or on both sides of the substrate layer 1, as needed, for the purpose of improving adhesion to a layer adjacent to the substrate layer. That is, the coating layer provided on the substrate layer may be a layer intended to improve printability, formability, etc., or may be a layer intended to improve the adhesiveness of the substrate layer. Even when the coating layer is intended to improve the adhesiveness of the substrate layer, the resin and thickness forming the coating layer may be exemplified as similar to the resin and thickness of the coating layer described above. Furthermore, the above-mentioned lubricants and additives may be included, but if there is an adjacent layer on the opposite side of the substrate layer from the coating layer, it is preferable not to include lubricants or additives.

[0049] [Adhesive layer 2] In the packaging material for an electricity storage device of the present disclosure, the adhesive layer 2 is a layer that is provided between the base layer 1 and the barrier layer 3 as 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 evaporation 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. 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 of the adhesive components.

[0052] Examples of polyurethane adhesives include polyurethane adhesives containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred examples include two-component curing polyurethane adhesives that use a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the base agent and an aromatic or aliphatic polyisocyanate as the curing agent. Furthermore, as the polyol compound, it is preferable to use a polyester polyol that has hydroxyl groups on the side chain in addition to the terminal hydroxyl groups of the repeating unit. Forming the adhesive layer 2 from 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, and the like. When the adhesive layer 2 contains a colorant, the exterior material for an electricity storage device can be colored. Known colorants such as pigments and dyes can be used as the colorant. 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 in order to give the exterior appearance of the electrical storage device packaging material a black color, for example.

[0056] The average particle size of the pigment is not particularly limited and may be, for example, about 0.05 to 5 μm, and preferably about 0.08 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution measuring device.

[0057] The content of the pigment 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 together, but the lower limit is, for example, about 1 μm or more, or about 2 μm or more, and the upper limit is about 10 μm or less, or about 5 μm or less, and preferred ranges are about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, or 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, the surface of the adhesive layer 2, or the surface of the barrier layer 3. Known colorants such as pigments and dyes can be used. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[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 at least prevents the penetration of moisture.

[0063] Examples of the barrier layer 3 include metal foils, vapor-deposited films, and resin layers having barrier properties. Vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Resin layers include fluorine-containing resins such as polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of fluoroalkyl units, as well as ethylene-vinyl alcohol copolymers. Examples of the barrier layer 3 also include resin films comprising at least one of these vapor-deposited films and resin layers. The barrier layer 3 may comprise multiple layers. The barrier layer 3 preferably includes a layer composed of a metal material. Specific examples of metal materials constituting the barrier layer 3 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, the barrier layer 3 preferably includes at least one of aluminum alloy foil and stainless steel foil.

[0064] From the viewpoint of improving the formability of the electrical storage device packaging material, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of further improving formability, an iron-containing aluminum alloy foil is preferred. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. By setting the iron content to 0.1% by mass or more, an electrical storage device packaging material with better formability can be obtained. By setting the iron content to 9.0% by mass or less, an electrical storage device packaging material with better flexibility can be obtained. Examples of soft aluminum alloy foils include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may be added as needed. Softening can be achieved by annealing or other methods.

[0065] Examples of stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. From the viewpoint of providing an exterior material for an electricity storage device that has excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0066] Specific examples of austenitic stainless steels that can be used to form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0067] In the case of a metal foil, the thickness of the barrier layer 3 should be such that it at least functions as a barrier layer that prevents moisture penetration, and is, for example, about 9 to 200 μm. The upper limit of the thickness of the barrier layer 3 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less, and the lower limit is preferably about 10 μm or more, even more preferably about 20 μm or more, and more preferably about 25 μm or more. Preferred ranges for the thickness include about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 3 is made of an aluminum alloy foil, the above-mentioned range is particularly preferred. In particular, when the barrier layer 3 is made of a stainless steel foil, the upper limit of the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less, and the lower limit is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred thickness ranges include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0068] Furthermore, when the barrier layer 3 is a metal foil, it is preferable that a corrosion-resistant coating be provided on at least the surface opposite the substrate layer to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film formed by applying, to the surface of the barrier layer, for example, a hydrothermal conversion treatment such as boehmite treatment, a chemical conversion treatment, anodizing treatment, a nickel or chromium plating treatment, or a corrosion prevention treatment such as applying a coating agent, to provide the barrier layer with corrosion resistance. The corrosion-resistant coating may be formed by one type of treatment or a combination of two or more types. Furthermore, not only one layer but also multiple layers can be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved by a treatment agent to form a metal compound 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 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 3.

[0069] The corrosion-resistant coating prevents delamination between the barrier layer (e.g., aluminum alloy foil) and the substrate layer during molding of the exterior packaging material for an electricity storage device, prevents dissolution and corrosion of the barrier layer surface due to hydrogen fluoride produced by the reaction between the electrolyte and water, and in particular prevents dissolution and corrosion of aluminum oxide present on the barrier layer surface when the barrier layer is an aluminum alloy foil, and also improves the adhesion (wettability) of the barrier layer surface, thereby preventing delamination between the substrate layer and the barrier layer during heat sealing and between the substrate layer and the barrier layer during molding.

[0070] Various corrosion-resistant coatings formed by chemical conversion treatments are known, including 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 inner surface of a barrier layer (e.g., an aluminum alloy foil) using a well-known method such as alkali immersion, electrolytic cleaning, acid pickling, electrolytic pickling, or acid activation, and then coating the degreased surface with a treatment solution primarily 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 primarily composed of a nonmetallic phosphate and a mixture of these nonmetallic salts, or a mixture of these with a synthetic resin, 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, or may be a chromate treatment using an aminated phenol polymer having repeating units represented by the following general formulas (1) to (4): In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more types.The acrylic resin is preferably polyacrylic acid, 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. A derivative of polyacrylic acid, such as an ammonium salt, a sodium salt, or an amine salt of polyacrylic acid, is 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, or 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 and used.

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] 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 2Examples 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 2 Examples 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 formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group, or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having repeating units represented by the formulas (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 the functional group (-CHNR 1 R 2 The aminated phenol polymers can be used singly or in combination of two or more.

[0076] 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 has 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. The liquid dispersion medium for the rare earth element oxide sol can be 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 composed 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 are 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, and 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.

[0077] An example of a corrosion-resistant coating is one formed by applying a solution of fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, or barium sulfate dispersed in phosphoric acid to the surface of a barrier layer and baking the coating at 150°C or higher.

[0078] 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.

[0079] The composition of the corrosion-resistant film can be analyzed using, for example, time-of-flight secondary ion mass spectrometry.

[0080] 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 applying 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, in terms of chromium, of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, the phosphorus compound in terms of phosphorus, and the aminated phenol polymer in an amount, in terms of phosphorus, of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, per unit area.

[0081] 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 or 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 the thickness of the corrosion-resistant coating, for example, by measuring the thickness of the coating with secondary ions consisting of Ce, P, and O (e.g., Ce2PO4 + , CePO4 - At least one of the following ions may be present: Cr, P, and O secondary ions (e.g., CrPO2 + , CrPO4 - Peaks derived from at least one of the above are detected.

[0082] 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, using an acid degreasing agent prepared by dissolving a fluorine-containing compound in an inorganic acid for the degreasing treatment not only degreases the metal foil but also forms a passive metal fluoride. In such cases, only the degreasing treatment may be performed.

[0083] [Thermal adhesive resin layer 4] In the packaging material for an electricity storage device of the present disclosure, the heat-sealable resin layer 4 corresponds to the innermost layer and is a layer (sealant layer) that functions to seal the electricity storage device elements by heat-sealing the heat-sealable resin layers together when the electricity storage device is assembled.

[0084] 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 Near and wave number 1780cm -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 when measured 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.

[0085] 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.

[0086] The polyolefin may also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, preferred are cyclic alkenes, and more preferred are norbornene.

[0087] Acid-modified polyolefins are polymers modified by block polymerization or graft polymerization of polyolefins with an acid component. Examples of acid-modified polyolefins include the above-mentioned polyolefins, copolymers of the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, and crosslinked polyolefins. Examples of acid components 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.

[0088] 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.

[0089] 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.

[0090] The thermally adhesive resin layer 4 may be formed of one type of resin alone or may be formed of a blend polymer of two or more types of resins. Furthermore, the thermally adhesive resin layer 4 may be formed of only one layer, or may be formed of two or more layers of the same or different resins.

[0091] Furthermore, the heat-sealable resin layer 4 may contain a lubricant, etc., as necessary. When the heat-sealable resin layer 4 contains a lubricant, the moldability of the electrical storage device packaging material can be improved. The lubricant is not particularly limited, and known lubricants can be used. The lubricants may be used alone or in combination of two or more.

[0092] 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.

[0093] When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount of the lubricant present is not particularly limited, but from the viewpoint of improving the formability of the packaging material for an electricity storage device, it is preferably 10 to 50 mg / m 2 approximately, more preferably 15 to 40 mg / m 2 The degree of

[0094] 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.

[0095] 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 together and seal the electricity storage device element, but may be, for example, about 100 μm or less, preferably about 85 μm or less, more preferably about 10 to 85 μm, or about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described below is greater than 10 μm, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, more preferably about 10 to 45 μm, or about 15 to 45 μm. For example, when the thickness of the adhesive layer 5 described below is 10 μm or less 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.

[0096] [Adhesive layer 5] In the packaging material for an electricity storage device of the present disclosure, the adhesive layer 5 is a layer that is provided as needed between the barrier layer 3 (or corrosion-resistant film) and the heat-sealable resin layer 4 in order to firmly bond them together.

[0097] The adhesive layer 5 is formed from a resin capable of bonding the barrier layer 3 and the heat-sealable resin layer 4. The resin used to form the adhesive layer 5 can be, for example, the same adhesive as exemplified for the adhesive layer 2. The resin used to form the adhesive layer 5 preferably contains a polyolefin skeleton, such as the polyolefins and acid-modified polyolefins exemplified for the heat-sealable resin layer 4. The presence of a polyolefin skeleton in the resin constituting the adhesive layer 5 can be determined by, for example, infrared spectroscopy or gas chromatography-mass spectrometry, and the analysis method is not particularly limited. Furthermore, when the resin constituting the adhesive layer 5 is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wavenumber of 1760 cm. -1 Near and wave number 1780cm -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.

[0098] From the viewpoint of firmly bonding the barrier layer 3 and the heat-sealable resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. Particularly preferred examples of the acid-modified polyolefin include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0099] Furthermore, from the viewpoint of reducing the thickness of the electrical storage device packaging material while providing an electrical storage device packaging material that has excellent shape stability after molding, the adhesive layer 5 is more preferably a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of the acid-modified polyolefin include those mentioned above.

[0100] 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. It is particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. The adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, more preferably polyurethane and epoxy resin. A preferred polyester is, for example, an amide ester resin. Amide ester resins are generally produced by the reaction of a carboxyl group with an oxazoline group. The adhesive layer 5 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. In addition, if unreacted compounds of curing agents such as compounds having an isocyanate group, compounds having an oxazoline group, and epoxy resins remain in the adhesive layer 5, the presence of the unreacted compounds can be confirmed by a method selected from, for example, infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

[0101] 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 COC 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 COC bond include curing agents having an oxazoline group, curing agents having an epoxy group, and polyurethane. 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.

[0102] The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively improving 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, biuret compounds, and isocyanurates.

[0103] 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 can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0104] 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.

[0105] 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 can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0106] An example of a compound having an epoxy group is an epoxy resin. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy 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 first disclosure, the weight-average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) under conditions using polystyrene as a standard sample.

[0107] Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, etc. One type of epoxy resin may be used alone, or two or more types may be used in combination.

[0108] 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 can effectively improve the adhesion between the barrier layer 3 and the adhesive layer 5.

[0109] 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.

[0110] The proportion of polyurethane in 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 adhesive layer 5. This effectively improves the adhesion between barrier layer 3 and adhesive layer 5 in an atmosphere containing components that induce corrosion of the barrier layer, such as an electrolyte solution.

[0111] 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.

[0112] The upper limit of the thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, about 10 μm or less, less than about 10 μm, about 8 μm or less, about 5 μm or less, or about 3 μm or less, and the lower limit is preferably about 0.1 μm or more, or about 0.5 μm or more. The thickness range is preferably about 0.1 to 50 μm, or less than 0.1 From the viewpoint of suppressing curling during molding of the exterior material for an electricity storage device, the thickness of adhesive layer 5 is preferably about 0.5 μm to 10 μm, about 0.5 to 8 μm, about 0.5 to 5 μm, or about 0.5 to 3 μm. More specifically, when the adhesive layer 2 is an adhesive such as that exemplified above or a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably about 1 to 10 μm, more preferably 1 μm or more but less than 10 μm, even more preferably about 1 to 8 μm, even more preferably about 1 to 5 μm, and even more preferably about 1 to 3 μm, from the viewpoint of suppressing curling during molding of the electrical storage device packaging material. Furthermore, when a resin such as that exemplified above for the thermally adhesive 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 such as that exemplified above 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 such as that exemplified above for the thermally adhesive resin layer 4 is used, the adhesive layer 5 can be formed, for example, by extrusion molding the thermally adhesive resin layer 4 and the adhesive layer 5 together.

[0113] [Surface coating layer 6] The packaging material for an electricity storage device according to the present disclosure may have a surface coating layer 6 on the substrate layer 1 (the side of the substrate layer 1 opposite to the barrier layer 3) as needed, 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.

[0114] The surface coating layer 6 can be formed from a resin such as polyvinylidene chloride, polyester, polyurethane, acrylic resin, or epoxy resin.

[0115] 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.

[0116] Examples of two-component curing polyurethanes include polyurethanes containing a base agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred examples include two-component curing polyurethanes that use a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the base agent and an aromatic or aliphatic polyisocyanate as the curing agent. Furthermore, it is preferable to use a polyester polyol that has hydroxyl groups on the side chain in addition to the terminal hydroxyl groups of the repeating unit as the polyol compound. Forming the surface coating layer 6 from polyurethane provides the electrical storage device exterior material with excellent electrolyte resistance.

[0117] The surface coating layer 6 may contain additives such as the aforementioned lubricants, antiblocking agents, matting agents, flame retardants, antioxidants, tackifiers, and antistatic agents, at least on the surface and / or inside of the surface coating layer 6, as needed, depending on the functionality to be imparted 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.

[0118] 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.

[0119] 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, cost, and the like. The additives may also be subjected to various surface treatments, such as insulation treatment and high-dispersibility treatment.

[0120] 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.

[0121] The thickness of the surface coating layer 6 is not particularly limited as long as the surface coating layer 6 exhibits the above-mentioned functions, and may be, for example, about 0.5 to 10 μm, and preferably about 1 to 5 μm.

[0122] 3. Manufacturing method for exterior materials for power storage devices The method for producing the electrical storage device packaging material is not particularly limited as long as it can produce a laminate in which the layers of the electrical storage device packaging material of the present invention are laminated, and examples include a method comprising a step of laminating at least a substrate layer 1, a barrier layer 3, and a heat-sealable resin layer 4 in this order. In the method for producing the electrical storage device packaging material 10 of the present disclosure, the slope of the stress-strain curve in the MD direction when the tensile elongation of the laminate constituting the electrical storage device packaging material 10 changes from 1% to 5% is 700 MPa or less. Details of the electrical storage device packaging material 10 of the present disclosure are as described above.

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

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

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

[0126] 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.

[0127] 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 needed 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.

[0128] 4. Applications of exterior materials for energy storage devices The exterior packaging material for an electricity storage device according to the present disclosure is used in a package for hermetically housing an electricity storage device element such as a positive electrode, a negative electrode, an electrolyte, etc. That is, an electricity storage device can be formed by housing an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte in a package formed from the exterior packaging material for an electricity storage device according to the present disclosure.

[0129] Specifically, an electricity storage device using the electricity storage device packaging material is provided by covering an electricity storage device element having 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 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 the heat-sealable resin layers of the flange portion are heat-sealed 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).

[0130] The exterior material for an electricity storage device according to 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 according to 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 according to the present disclosure is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, all-solid-state 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, lithium ion batteries and lithium ion polymer batteries are suitable applications for the exterior material for an electricity storage device according to the present disclosure. [Example]

[0131] 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.

[0132] The biaxially oriented nylon films and aluminum alloy foils used as the substrate layer and barrier layer in the examples and comparative examples are as follows:

[0133] <Base material layer> ON1: Biaxially oriented nylon film (produced by simultaneous biaxial stretching using the inflation method, the ratio of tensile break elongation in the MD direction to the tensile break elongation in the TD direction (MD / TD) is 1.38, and the tensile break elongation in the MD direction is greater than the tensile break elongation in the TD direction) ON2: Biaxially oriented nylon film (produced by simultaneous biaxial stretching using the inflation method. The ratio of the tensile breaking elongation in the MD direction to the tensile breaking elongation in the TD direction (MD / TD) is 1.16, meaning that the tensile breaking elongation in the MD direction is similar to the tensile breaking elongation in the TD direction.) ON3: Biaxially oriented nylon film (produced by sequential biaxial stretching using a tenter system, with a ratio of tensile elongation at break in the MD direction to the tensile elongation at break in the TD direction (MD / TD) of 1.27) ON4: A biaxially oriented nylon film similar to ON3 except for the thickness, with a coating layer (a polyester polyurethane containing a lubricant applied to a thickness of 300 nm or less) on the surface opposite the barrier layer, and a coating layer (a polyester polyurethane applied to a thickness of 300 nm or less) on the surface facing the barrier layer. ON5: A biaxially oriented nylon film of ON3 with a coating layer (polyester polyurethane applied to a thickness of 300 nm or less) on the barrier layer side. PET: Polyethylene terephthalate film (formed by sequential biaxial stretching using the tenter method)

[0134] <Barrier layer> ALM1: Aluminum alloy foil (aluminum alloy foil rolled by the roll bearing method and having the composition of JIS H4160:1994 A8079H-O) ALM2: Aluminum alloy foil (rolled by the roll bearing method, aluminum alloy foil with the composition of JIS H4160:1994 A8021H-O) ALM3: Aluminum alloy foil (aluminum alloy foil with the composition of JIS H4160:1994 A8021H-O, rolled using the Morgoil bearing method) ALM4: Aluminum alloy foil (rolled using the Morgoil bearing method, aluminum alloy foil with the composition of JIS H4160:1994 A8021H-O) (composition different from ALM3)

[0135] <Manufacturing of exterior materials for energy storage devices> [Example 1] A barrier layer consisting of aluminum alloy foil (ALM3, 40 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON3, 25 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0136] Next, a two-component curing adhesive (acid-modified polypropylene and epoxy compound) was applied to the barrier layer side of the resulting laminate, forming an adhesive layer (2 μm thick after curing) on ​​the aluminum alloy foil. Next, an unstretched polypropylene film (CPP, 30 μm thick) was laminated on top of the adhesive layer as the heat-sealable resin layer (first layer) using the dry lamination method. The resulting laminate was then aged and heated. Furthermore, polypropylene (PP, 50 μm thick) was laminated on top of the barrier layer as the heat-sealable resin layer (second layer) using melt extrusion to form a two-layer structure consisting of an adhesive layer and a heat-sealable resin layer (20 μm + 50 μm). The laminate structure of the power storage device packaging material is shown in Table 1.

[0137] Erucic acid amide was present as a lubricant on both sides of the exterior material for an electricity storage device to form a lubricant layer, which was the same in Examples 2 to 13 and Comparative Examples 1 and 2 below.

[0138] [Example 2] A barrier layer consisting of aluminum alloy foil (ALM1, 40 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON1, 25 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0139] Next, a two-component curing adhesive (acid-modified polypropylene and epoxy compound) was applied to the barrier layer side of the resulting laminate, forming an adhesive layer (4 μm thick after curing) on ​​the aluminum alloy foil. Next, an unstretched polypropylene film (CPP, 30 μm thick) was laminated on top of the adhesive layer as the heat-sealable resin layer (first layer) using the dry lamination method. The resulting laminate was then aged and heated. Furthermore, polypropylene (PP, 50 μm thick) was laminated on top of the barrier layer as the heat-sealable resin layer (second layer) using melt extrusion to form a two-layer structure consisting of an adhesive layer and a heat-sealable resin layer (20 μm + 50 μm). The laminate structure of the power storage device packaging material is shown in Table 1.

[0140] [Example 3] A barrier layer consisting of aluminum alloy foil (ALM1, 40 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON1, 25 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0141] Next, a two-component curing adhesive (acid-modified polypropylene and epoxy compound) was applied to the barrier layer side of the resulting laminate, forming an adhesive layer (4 μm thick after curing) on ​​the aluminum alloy foil. Next, an unstretched polypropylene film (CPP, 30 μm thick) was laminated on top of the adhesive layer as the heat-sealable resin layer (first layer) using the dry lamination method. The resulting laminate was then aged and heated. Furthermore, polypropylene (PP, 20 μm thick) was laminated on top of the barrier layer as the heat-sealable resin layer (second layer) using melt extrusion to form a two-layer structure consisting of an adhesive layer and a heat-sealable resin layer (20 μm + 20 μm). This produced a packaging material for an electricity storage device, in which the following layers were laminated in this order: biaxially oriented nylon film (25 μm), adhesive layer (3 μm), barrier layer (40 μm), adhesive layer (4 μm), and heat-sealable resin layer (30 μm + 20 μm). The layer structure of the packaging material for an electricity storage device is shown in Table 1.

[0142] [Example 4] A barrier layer consisting of aluminum alloy foil (ALM2, 35 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON2, 15 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0143] Next, a two-component curing adhesive (acid-modified polypropylene and epoxy compound) was applied to the barrier layer side of the resulting laminate, forming an adhesive layer (2 μm thick after curing) on ​​the aluminum alloy foil. Next, an unstretched polypropylene film (CPP, 30 μm thick) was laminated on top of the adhesive layer using the dry lamination method, resulting in an adhesive layer / heat-sealable resin layer laminated on the barrier layer. Next, the resulting laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, in which a biaxially oriented nylon film (15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (2 μm) / heat-sealable resin layer (30 μm) were laminated in this order. The laminate configuration of the exterior packaging material for an electricity storage device is shown in Table 1.

[0144] [Example 5] A barrier layer consisting of aluminum alloy foil (ALM4, 35 μm thick) with acid-resistant coatings formed on both sides was laminated by dry lamination onto a biaxially oriented nylon film (ON4, 20 μm thick) serving as a substrate layer. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings formed on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate.

[0145] Next, maleic anhydride-modified polypropylene (PPa, 15 μm thick) as an adhesive layer and polypropylene (15 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer side of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain a packaging material for an electricity storage device, in which a biaxially oriented nylon film (20 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (15 μm) / heat-sealable resin layer (15 μm) were laminated in this order. The layer configuration of the packaging material for an electricity storage device is shown in Table 1.

[0146] [Example 6] A barrier layer consisting of aluminum alloy foil (ALM2, 25 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON1, 12 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0147] Next, maleic anhydride-modified polypropylene (PPa, 14 μm thick) as an adhesive layer and polypropylene (PP, 10 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer side of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, in which a biaxially oriented nylon film (12 μm) / adhesive layer (3 μm) / barrier layer (25 μm) / adhesive layer (14 μm) / heat-sealable resin layer (10 μm) were laminated in this order. The laminate configuration of the exterior packaging material for an electricity storage device is shown in Table 1.

[0148] [Example 7] A laminate film was prepared as a substrate layer, consisting of a polyethylene terephthalate film (PET, 12 μm thick) and a biaxially oriented nylon film (ON3, 15 μm thick) laminated with an adhesive layer (3 μm thick after curing) formed from a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound). Next, a barrier layer composed of an aluminum alloy foil (ALM3, 40 μm thick) with an acid-resistant coating formed on both sides was laminated on the biaxially oriented nylon film substrate layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with an acid-resistant coating formed on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate.

[0149] Next, maleic anhydride-modified polypropylene (PPa, 40 μm thick) as an adhesive layer and polypropylene (40 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer side of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, in which a polyethylene terephthalate film (12 μm) / adhesive layer (3 μm) / biaxially oriented nylon film (15 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (40 μm) / heat-sealable resin layer (40 μm) were laminated in this order. The laminate configuration of the exterior packaging material for an electricity storage device is shown in Table 1.

[0150] [Example 8] A barrier layer consisting of aluminum alloy foil (ALM1, 40 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON1, 25 μm thick) as a substrate layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) containing carbon black was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming a black adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate.

[0151] Next, maleic anhydride-modified polypropylene (PPa, 23 μm thick) as an adhesive layer and polypropylene (PP, 23 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer side of the resulting laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, a resin composition (3 μm thick after curing) containing precipitated barium sulfate (average particle size 1 μm) as a filler, erucic acid amide, and an acrylate resin (average particle size 2 μm) was gravure-coated onto the surface of the biaxially oriented nylon film of the resulting laminate, forming a matte surface coating layer. The resulting laminate was then aged and heated to obtain a black exterior packaging material for an electricity storage device, consisting of a surface coating layer (3 μm), a biaxially oriented nylon film (25 μm), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (23 μm), and a heat-sealable resin layer (23 μm) laminated in this order. The laminate structure of the exterior material for the electricity storage device is shown in Table 1.

[0152] [Example 9] A barrier layer consisting of aluminum alloy foil (ALM3, 40 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON3, 25 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0153] Next, a two-component curing adhesive (acid-modified polypropylene and epoxy compound) was applied to the barrier layer side of the resulting laminate, forming an adhesive layer (2 μm thick after curing) on ​​the aluminum alloy foil. Next, an unstretched polypropylene film (CPP, 30 μm thick) was laminated on top of the adhesive layer using the dry lamination method, resulting in an adhesive layer / thermal adhesive resin layer laminated on the barrier layer. Next, the resulting laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, in which a biaxially oriented nylon film (25 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (2 μm) / thermal adhesive resin layer (30 μm) were laminated in this order. The laminate configuration of the exterior packaging material for an electricity storage device is shown in Table 1.

[0154] [Example 10] A barrier layer consisting of aluminum alloy foil (ALM1, 40 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON1, 25 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0155] Next, a two-component curing adhesive (acid-modified polypropylene and epoxy compound) was applied to the barrier layer side of the resulting laminate, forming an adhesive layer (4 μm thick after curing) on ​​the aluminum alloy foil. Next, an unstretched polypropylene film (CPP, 30 μm thick) was laminated on top of the adhesive layer using the dry lamination method, resulting in an adhesive layer / heat-sealable resin layer laminated on the barrier layer. Next, the resulting laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, in which a biaxially oriented nylon film (25 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (4 μm) / heat-sealable resin layer (30 μm) were laminated in this order. The laminate configuration of the exterior packaging material for an electricity storage device is shown in Table 1.

[0156] [Example 11] A barrier layer consisting of aluminum alloy foil (ALM3, 40 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON3, 25 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0157] Next, a two-component curing adhesive (acid-modified polypropylene and epoxy compound) was applied to the barrier layer side of the resulting laminate, forming an adhesive layer (2 μm thick after curing) on ​​the aluminum alloy foil. Next, an unstretched polypropylene film (CPP, 40 μm thick) was laminated on top of the adhesive layer using the dry lamination method, resulting in an adhesive layer / thermal adhesive resin layer laminated on the barrier layer. Next, the resulting laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, in which a biaxially oriented nylon film (25 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (2 μm) / thermal adhesive resin layer (40 μm) were laminated in this order. The laminate configuration of the exterior packaging material for an electricity storage device is shown in Table 1.

[0158] [Example 12] A barrier layer consisting of aluminum alloy foil (ALM1, 40 μm thick) with acid-resistant coatings on both sides was laminated onto a biaxially oriented nylon film (ON1, 25 μm thick) as a base layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0159] Next, maleic anhydride-modified polypropylene (PPa, thickness 23 μm) as an adhesive layer and polypropylene (PP, thickness 23 μm) as a heat-sealable resin layer were co-extruded onto the barrier layer side of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain an exterior packaging material for an electricity storage device, in which a biaxially oriented nylon film (25 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (23 μm) / heat-sealable resin layer (23 μm) were laminated in this order. The laminate configuration of the exterior packaging material for an electricity storage device is shown in Table 1.

[0160] [Example 13] A barrier layer consisting of aluminum alloy foil (ALM3, 40 μm thick) with acid-resistant coatings on both sides was laminated by dry lamination onto a biaxially oriented nylon film (ON5, 25 μm thick) serving as a substrate layer. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate.

[0161] Next, a two-component curing adhesive (acid-modified polypropylene and epoxy compound) was applied to the barrier layer side of the resulting laminate, forming an adhesive layer (2 μm thick after curing) on ​​the aluminum alloy foil. Next, an unstretched polypropylene film (CPP, 30 μm thick) was laminated on top of the adhesive layer as the heat-sealable resin layer (first layer) using the dry lamination method. The resulting laminate was then aged and heated. Furthermore, polypropylene (PP, 50 μm thick) was laminated on top of the barrier layer as the heat-sealable resin layer (second layer) using melt extrusion to form a two-layer structure consisting of an adhesive layer and a heat-sealable resin layer (20 μm + 50 μm). The laminate structure of the power storage device packaging material is shown in Table 1.

[0162] [Comparative Example 1] A biaxially oriented nylon film (ON1, 15 μm thick) and another biaxially oriented nylon film (ON1, 25 μm thick) were laminated together as a substrate layer using an adhesive layer (3 μm thick after curing) formed with a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound). Next, a barrier layer composed of aluminum alloy foil (ALM1, 40 μm thick) with acid-resistant coatings formed on both sides was laminated on the biaxially oriented nylon film (ON1, 25 μm thick) of the substrate layer using a dry lamination method. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings formed on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. The adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were then laminated, followed by an aging treatment, to produce a substrate layer / adhesive layer / barrier layer laminate.

[0163] Next, maleic anhydride-modified polypropylene (PPa, 23 μm thick) as an adhesive layer and polypropylene (PP, 23 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer side of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain a packaging material for an electricity storage device, in which a biaxially oriented nylon film (15 μm) / adhesive layer (3 μm) / biaxially oriented nylon film (25 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (23 μm) / heat-sealable resin layer (23 μm) were laminated in this order. The layer configuration of the packaging material for an electricity storage device is shown in Table 1.

[0164] Comparative Example 2 A laminate film was prepared as a substrate layer, consisting of a biaxially oriented nylon film (ON1, 15 μm thick) and another biaxially oriented nylon film (ON1, 25 μm thick) laminated with an adhesive layer (3 μm thick after curing) formed from a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound). Next, a barrier layer composed of aluminum alloy foil (ALM2, 35 μm thick) with acid-resistant coatings formed on both sides was laminated on the biaxially oriented nylon film (ON1, 25 μm thick) of the substrate layer by dry lamination. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum alloy foil with acid-resistant coatings formed on both sides, forming an adhesive layer (3 μm thick after curing) on ​​the aluminum alloy foil. Next, the adhesive layer on the aluminum alloy foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate.

[0165] Next, maleic anhydride-modified polypropylene (PPa, 23 μm thick) as an adhesive layer and polypropylene (PP, 23 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer side of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was aged and heated to obtain a packaging material for an electricity storage device, in which a biaxially oriented nylon film (15 μm) / adhesive layer (3 μm) / biaxially oriented nylon film (25 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (23 μm) / heat-sealable resin layer (23 μm) were laminated in this order. The layer structure of the packaging material for an electricity storage device is shown in Table 1.

[0166] [Table 1]

[0167] In Table 1, ON stands for biaxially oriented nylon film, PET stands for polyethylene terephthalate film, DL stands for adhesive layer or bond layer formed by dry lamination, ALM stands for aluminum alloy foil, CPP stands for unstretched polypropylene film, PPa stands for maleic anhydride-modified polypropylene, PP stands for polypropylene, and Matt stands for matte surface coating layer. The numbers in parentheses indicate the thickness of each layer.

[0168] <Slope of stress-strain curve> The slopes of the stress-strain curves corresponding to the two strain points of 0.05% and 0.25% tensile strains, and the slopes of the stress-strain curves corresponding to the two strain points of 1% and 5% tensile strains were measured in the MD and TD directions, respectively, for each of the electrical storage device exterior materials obtained above. These were measured using a tensile tester (Shimadzu Corporation, AG-Xplus (trade name)). Other than the strain ranges mentioned above, measurements were performed in accordance with JIS K 7161-1:2014. The samples were rectangular, 15 mm wide and 50 mm long or longer (the length direction for measurements in the MD direction was the MD, and the length direction for measurements in the TD direction was the TD). The gauge length was 30 mm, the tensile speed was 50 mm / min, and the test environment was 23°C. The slopes of the stress-strain curves at each strain were calculated using the least-squares regression line. The calculations used one measurement point every 0.1 seconds, 10 data points for the slope of the tensile strain from 0.05% to 0.25%, and 144 data points for the slope of the tensile strain from 1% to 5%. The calculations were performed using the LINEST function in Microsoft Excel (Microsoft Corporation), a spreadsheet program. The results are shown in Tables 2 and 3.

[0169] <Evaluation of molding curl at a molding depth of 8 mm> Each of the electrical storage device packaging materials obtained above was cut into strips measuring 150 mm in the transverse direction (TD) × 90 mm in the machine direction (MD), which were used as test samples. The MD of the electrical storage device packaging material corresponded to the rolling direction (RD) of the aluminum alloy foil, and the TD of the electrical storage device packaging material corresponded to the TD of the aluminum alloy foil. A 31.6 mm × 54.5 mm rectangular male mold (the surface had a maximum height roughness (nominal Rz value) of 1.6 μm, as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Appendix 1 (Reference), with a corner R2.0 mm and a ridge R1.0 mm) was placed between the male mold and a female mold (the surface had a maximum height roughness (nominal Rz value) of 1.6 μm, as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Appendix 1 (Reference)), with a clearance of 0.3 mm. The maximum height roughness (nominal Rz value) of the comparative surface roughness standard specimen, as specified in Table 2, was 3.2 μm. Using a mold with a corner radius of 2.0 mm and a ridge radius of 1.0 mm, the test sample was placed on the female mold so that the heat-sealable resin layer was positioned on the male mold side. The test sample was pressed with a pressure (surface pressure) of 0.25 MPa to obtain a dimension of 31.6 mm (MD) × 54.5 mm (TD) with a molding depth of 8 mm, and cold-formed (single-stage drawing molding). Details of the molding position are shown in FIG. 5. As shown in FIG. 5, molding was performed at a position where the shortest distance d between the rectangular molding portion M and the end P of the test sample (exterior material 10 for an electricity storage device) was 70.5 mm. Next, the molded test sample (exterior packaging material 10 for an electricity storage device) was placed on a horizontal surface 20 as shown in Figure 6, and the maximum distance t in the vertical direction y from the horizontal surface 20 to the end P was taken as the maximum height of the curled portion. The maximum heights of 10 test samples were measured using a Digimatic Height Gauge (HD-30AX, manufactured by Mitutoyo Corporation), and the average value was taken as the molding curl. The results are shown in Table 2.

[0170] <Evaluation of formability> Each of the resulting electrical storage device packaging materials was cut into a rectangle measuring 90 mm in length (MD) and 150 mm in width (TD) to prepare a test sample. The MD of the electrical storage device packaging material corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the electrical storage device packaging material corresponds to the TD of the aluminum alloy foil. The test sample was placed in a 25°C environment in a forming mold (female mold, surface has a rectangular shape in plan view, a diameter of 31.6 mm (MD) x 54.5 mm (TD) and a maximum height roughness (nominal value of Rz) of 3.2 μm, corner R2.0 mm, ridge R1.0 mm, as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Annex 1 (Reference)) and a corresponding forming mold (male mold, surface has a maximum height roughness (nominal value of Rz) of 3.2 μm, corner R2.0 mm, ridge R1.0 mm, as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Annex 1 (Reference)). The maximum height roughness (nominal Rz value) of the comparative surface roughness standard specimen, as specified in Table 2, was 1.6 μm. Using a corner radius of 2.0 mm and a ridge radius of 1.0 mm, 10 samples were cold-formed (single-stage drawing) at a pressing pressure (surface pressure) of 0.25 MPa, varying the forming depth from 0.5 mm in 0.5 mm increments, to form a rectangular housing (for the energy storage device element) in plan view. The test sample was placed on a female mold with the heat-sealable resin layer facing the male mold. The clearance between the male and female molds was 0.3 mm. The cold-formed samples were illuminated with a penlight in a darkroom to check for pinholes or cracks in the aluminum alloy foil. The deepest forming depth at which no pinholes or cracks occurred in the aluminum alloy foil in any of the 10 samples was defined as A mm, and the number of samples at which pinholes or other defects occurred at the shallowest forming depth in the aluminum alloy foil was defined as B. The value calculated using the following formula was rounded to two decimal places to determine the limit forming depth of the exterior material for an electricity storage device. The results are shown in Table 6. Limit forming depth = A mm + (0.5 mm / 10 pieces) x (10 pieces - B pieces)

[0171] [Table 2]

[0172] In Table 2, the values of the slope of the stress-strain (MPa) are the values obtained by rounding off the first decimal place of the measured values, respectively. Also, the values of the formed curl are the values obtained by rounding off the second decimal place of the measured values, respectively.

[0173]

Table 3

[0174] In Table 3, the values of the slope of the stress-strain (MPa) are the values obtained by rounding off the first decimal place of the measured values, respectively.

[0175] As shown in Table 2, for the exterior materials for power storage devices of Examples 1 to 13, the slopes of the stress-strain curves corresponding to the two strain points of 1% and 5% tensile strain in the MD direction are within a specific range of 700 MPa or less. Despite the formed depth being as deep as 8 mm, the formed curl of the exterior materials for power storage devices of Examples 1 to 13 was suppressed and was less than 35 mm. On the other hand, for the exterior materials for power storage devices of Comparative Examples 1 and 2, the slopes of the stress-strain curves corresponding to the two strain points of 1% and 5% tensile strain in the MD direction are outside the range of 700 MPa or less. Since the formed depth of the exterior materials for power storage devices of Comparative Examples 1 and 2 was as deep as 8 mm, the formed curl exceeded 35 mm. As shown in Table 3, regarding the slopes of the stress-strain curves corresponding to the two strain points of 0.05% and 0.25% tensile strain in the MD direction, for example, Examples 6, 9 to 11 were 4311 to 6373 MPa, which were much larger values than those of Comparative Examples 1 and 2, but the formed curl was suppressed more than that of Comparative Examples 1 and 2, and no clear relationship could be found between the tensile elastic modulus and the formed curl.

[0176] <Evaluation of formed curl at a formed depth of 8 mm with MD as the long side> The curl measured at a forming depth of 8 mm was measured in the same manner as in the <Evaluation of curl measured at a forming depth of 8 mm>, except that test samples were prepared from the packaging materials for electricity storage devices obtained in Examples 1, 4, and 11 to form strips of 150 mm in MD x 90 mm in TD, and that the molding using a mold was also performed by cold forming to a size of 31.6 mm (TD) x 54.5 mm (MD). The results are shown in Table 4.

[0177] [Table 4]

[0178] In Table 4, the values ​​of the forming curl are each measured and rounded to one decimal place.

[0179] The results shown for Examples 1, 4, and 11 in Table 4 indicate that the forming curl when MD is the long side is larger than the forming curl shown for Examples 1, 4, and 11 in Table 2, and that when applying an exterior material for an electricity storage device to an electricity storage device, it is more preferable to use it so that the long side direction of the accommodating section, which is rectangular in plan view, corresponds to the TD direction of the exterior material for an electricity storage device.

[0180] <Evaluation of molding curl at a molding depth of 6 mm> Except for the fact that the molding depth was set to a shallower 6 mm, the curl caused by molding was measured for each of the exterior packaging materials for electricity storage devices obtained in Examples 9, 10, and 11 at a molding depth of 6 mm in the same manner as in <Evaluation of curl caused by molding at a molding depth of 8 mm> above. The results are shown in Table 5.

[0181] [Table 5]

[0182] In Table 5, the values ​​of the forming curl are each measured and rounded to one decimal place.

[0183] From the results of Examples 9 to 11 shown in Table 5, when the forming depth is shallow, 6 mm, the forming curl is smaller than when the forming depth is deep, 8 mm, as shown in Table 2. As can be seen from these results, when experiments are performed with a small forming depth, problems related to forming curl are less likely to occur, and therefore it is difficult to recognize the problem of forming curl caused by increasing the forming depth.

[0184] [Table 6]

[0185] As described above, the present disclosure provides the following aspects of the invention. Item 1. The laminate is composed of at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, The laminate is an exterior material for an electricity storage device, in which the gradient of the stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the MD direction is 700 MPa or less. Item 2. The packaging material for an electricity storage device according to Item 1, wherein the laminate has a stress-strain curve in the TD direction corresponding to two strain points of 1% tensile strain and 5% tensile strain, with a slope of 630 MPa or less. Item 3. The packaging material for an electricity storage device according to Item 1 or 2, wherein the absolute value of the difference between the slope of a stress-strain curve corresponding to two strain points at 1% tensile strain and 5% tensile strain in the MD direction of the laminate and the slope of a stress-strain curve corresponding to two strain points at 1% tensile strain and 5% tensile strain in the TD direction of the laminate is 118 MPa or less. Item 4. An adhesive layer is provided between the barrier layer and the heat-sealable resin layer, Item 4. The packaging material for an electricity storage device according to any one of items 1 to 3, wherein the adhesive layer has a thickness of 10 μm or less. Item 5. The packaging material for an electricity storage device according to any one of Items 1 to 4, wherein the base layer is composed of a single layer of polyamide film. Item 6. The packaging material for an electricity storage device according to any one of Items 1 to 5, further comprising a surface coating layer on the side of the base material layer opposite to the heat-sealable resin layer side. Item 7. An electricity storage device, in which an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the exterior packaging material for an electricity storage device according to any one of Items 1 to 6. Item 8. The housing portion of the packaging body for housing the electricity storage device element has a rectangular shape in a plan view, Item 8. The electricity storage device according to item 7, wherein the long side direction of the storage section corresponds to the TD direction of the packaging material for an electricity storage device. Item 9. The method includes a step of laminating at least a base layer, a barrier layer, and a heat-sealable resin layer in this order to obtain a laminate, The laminate has a stress-strain curve in the MD direction corresponding to two strain points of 1% tensile strain and 5% tensile strain, with a gradient of 700 MPa or less. [Explanation of symbols]

[0186] 1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-fusible resin layer 5 Adhesive layer 6 Surface coating layer 10. Exterior materials for energy storage devices 100 packages 100a: Storage section for power storage device element

Claims

1. The laminate is composed of at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, The laminate has a stress-strain curve in the MD direction, the slope of which corresponds to two strain points of 1% tensile strain and 5% tensile strain, of 290 MPa or more and 700 MPa or less; An exterior material for an electricity storage device, wherein the absolute value of the difference between the slope of a stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the MD direction of the laminate and the slope of a stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the TD direction of the laminate is 118 MPa or less.

2. 2 . The packaging material for an electricity storage device according to claim 1 , wherein the barrier layer has a thickness of more than 50 μm and not more than 200 μm, and the base layer has a thickness of 2 μm or more and 25 μm or less.

3. 3. The packaging material for an electricity storage device according to claim 1, wherein the barrier layer has a thickness of more than 25 μm and not more than 50 μm, and the total thickness of layers inside the barrier layer is 24 μm or more and 34 μm or less.

4. The packaging material for an electricity storage device according to any one of claims 1 to 3, wherein the base material layer is a single layer.

5. The packaging material for an electricity storage device according to claim 4 , wherein the base layer is formed of a polyester film.

6. The packaging material for an electricity storage device according to any one of claims 1 to 5, which is composed of a laminate including at least a surface coating layer, the base material layer, the barrier layer, an adhesive layer, and the heat-sealable resin layer in this order.

7. The packaging material for an electricity storage device according to any one of claims 1 to 5, further comprising a surface coating layer on the opposite side of the base material layer from the barrier layer side.

8. The packaging material for an electricity storage device according to claim 6 or 7, wherein the surface coating layer contains an additive.

9. The packaging material for an electricity storage device according to claim 8 , wherein the additive includes at least one of an organic substance and an inorganic substance.

10. The packaging material for an electricity storage device according to claim 9 , wherein the inorganic substance comprises at least one selected from the group consisting of silica, kaolin, barium sulfate, and titanium oxide.

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

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

13. The packaging material for an electricity storage device according to any one of claims 1 to 12, wherein at least one surface of the barrier layer has a corrosion-resistant coating.

14. When the corrosion-resistant film was analyzed using time-of-flight secondary ion mass spectrometry, it was found that Ce + and Cr + The packaging material for an electricity storage device according to claim 13, wherein a peak derived from at least one of the following is detected.

15. The packaging material for an electricity storage device according to claim 13 or 14, wherein the corrosion-resistant coating contains at least one compound selected from the group consisting of a phosphorus compound salt, a chromium compound, a fluorine compound, and a triazine thiol compound.

16. An electricity storage device, comprising an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte, housed in a package formed from the exterior packaging material for an electricity storage device according to any one of claims 1 to 15.

17. the housing portion of the packaging body for the electric storage device element has a rectangular shape in a plan view, The electricity storage device according to claim 16 , wherein a long side direction of the housing portion corresponds to a TD direction of the packaging material for an electricity storage device.

18. The method includes a step of laminating at least a base layer, a barrier layer, and a heat-sealable resin layer in this order to obtain a laminate, The laminate has a stress-strain curve in the MD direction, the slope of which corresponds to two strain points of 1% tensile strain and 5% tensile strain, of 290 MPa or more and 700 MPa or less; A method for producing an exterior material for an electricity storage device, wherein the absolute value of the difference between the slope of a stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the MD direction of the laminate and the slope of a stress-strain curve corresponding to two strain points of 1% tensile strain and 5% tensile strain in the TD direction of the laminate is 118 MPa or less.

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