Packaging material for power storage device, method for producing the same, power storage device, and polyamide film

Abstract

To provide a packaging material for a power storage device in which breakage of the packaging material for the power storage device is suppressed when the power storage device fixed to a housing with a double-sided tape or the like is peeled from the housing.SOLUTION: A packaging material for a power storage device, comprising a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer in order from the outside, wherein the base material layer includes a polyamide film, and a crystallization index of the polyamide film measured from the outside of the base material layer by an ATR method of Fourier transform infrared spectroscopy is 1.50 or more.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Various types of electricity storage devices have been developed, and in all of them, 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., there has been a demand for electricity storage devices 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 laminate in which a base layer, a barrier layer, and a heat-sealable resin layer are laminated in this order has been proposed as an exterior material for an electricity storage device that can be easily processed into a variety of shapes and can be made thinner and lighter (see, for example, Patent Document 1).

[0005] In such an electrical storage device packaging material, a recess is generally formed by cold forming, and electrical storage device elements such as electrodes and electrolyte are placed in the space formed by the recess, and a heat-sealable resin layer is heat-sealed to obtain an electrical storage device in which the electrical storage device elements are housed inside the electrical storage device 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] Energy storage device elements contain rare metals and other components, and demand for these components is rapidly increasing. For this reason, when replacing an energy storage device in various products such as electrical equipment, there is a need to remove the device from the product and recover and reuse the various components contained in the energy storage device element.

[0008] In various products such as electrical appliances, electricity storage devices are firmly fixed to the housing of the product using double-sided tape, adhesives, or the like. Therefore, when removing the electricity storage device from the housing of the product, a large external force is applied to the electricity storage device. Specifically, electricity storage devices are generally removed from the housing using a metal spatula or the like, and a large external force is applied to the electricity storage device. If a large external force is applied to an exterior material for an electricity storage device made of a film-like laminate when removing the electricity storage device, there is a risk that the exterior material for an electricity storage device will be damaged.

[0009] Under these circumstances, the main object of the present disclosure is to provide an exterior material for an electricity storage device that is prevented from being damaged when the electricity storage device, which is fixed to the housing with double-sided tape or the like, is peeled off from the housing. [Means for solving the problem]

[0010] The inventors of the present disclosure conducted extensive studies to solve the above-mentioned problems, and as a result, they found that a packaging material for an electricity storage device that is composed of a laminate including, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer, the base layer containing a polyamide film, and the polyamide film having a crystallization index of a predetermined value or more as measured from the outside of the base layer by an ATR method of Fourier transform infrared spectroscopy, is prevented from being damaged when the electricity storage device is fixed to the housing with double-sided tape or the like and is peeled off from the housing.

[0011] 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 from the outside, the substrate layer includes a polyamide film, An outer casing material for an electricity storage device, wherein the polyamide film has a crystallization index of 1.50 or more as measured from the outside of the base layer by an ATR method of Fourier transform infrared spectroscopy. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide a packaging material for an electricity storage device that is suppressed from being damaged when an electricity storage device fixed to a housing with double-sided tape or the like is peeled off from the housing with a metal spatula, etc. The present disclosure also makes it possible to provide a method for manufacturing the packaging material for an electricity storage device, an electricity storage device that uses the packaging material for an electricity storage device, and a polyamide film that is suitable for use as a base layer of the packaging material for an electricity storage device. [Brief explanation of the drawings]

[0013] [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] 5A to 5C are schematic diagrams illustrating a procedure for producing a sample used in a peel test of an electricity storage device in an example. [Figure 6] 1A and 1B are a side view and a plan view, respectively, of a sample used in a peel test of an electricity storage device in an example. [Figure 7]1A is a side view and FIG. 1B is a plan view of a sample used in a peel test of an electricity storage device according to an example, with a double-sided tape attached thereto. [Figure 8] FIG. 10 is a schematic diagram illustrating how an electricity storage device is peeled off from a stainless steel plate using a metal spoon in a peel test of an electricity storage device in an example. DETAILED DESCRIPTION OF THE INVENTION

[0014] The packaging material for an electricity storage device of the present disclosure is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, the base material layer containing a polyamide film, and the polyamide film having a crystallization index of 1.50 or more measured from the outside of the base material layer by the ATR method of Fourier transform infrared spectroscopy. The packaging material for an electricity storage device of the present disclosure is suppressed from being damaged when an electricity storage device fixed to a housing with double-sided tape or the like is peeled off from the housing.

[0015] 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.

[0016] 1.Layer structure and physical properties of exterior materials for energy storage devices As shown in FIG. 1 , for example, an electrical storage device packaging material 10 according to the present disclosure is composed of a laminate including, in order from the outside, a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4. 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 of the electrical storage device packaging material 10 facing each other. In the laminate constituting the electrical storage device packaging material 10 according to the present disclosure, with the barrier layer 3 as the reference, the side of the heat-sealable resin layer 4 relative to the barrier layer 3 is on the inner side, and the side of the base material layer 1 relative to the barrier layer 3 is on the outer side.

[0017] 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, an adhesive layer 5 may have a 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 5, 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.

[0018] The thickness of the laminate constituting the electrical storage device packaging material 10 is not particularly limited, but from the viewpoints of cost reduction, improving energy density, etc., the upper limit is preferably about 180 μm or less, about 155 μm or less, or about 120 μm or less, and from the viewpoint of maintaining the function of the electrical storage device packaging material to protect the electrical storage device elements, the lower limit is preferably about 35 μm or more, about 45 μm or more, or about 60 μm or more, 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, and of these, 60 to 120 μm is particularly preferred.

[0019] In the packaging material 10 for an electricity storage device, the ratio of the total thickness of the base material layer 1, the adhesive layer 2 (which is provided as needed), the barrier layer 3, the adhesive layer 5 (which is provided as needed), the heat-sealable resin layer 4, and the surface coating layer 6 (which is provided as needed) to the thickness (total thickness) of the laminate constituting the packaging material 10 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 10 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 10 for an electricity storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0020] The base material layer 1 of the electrical storage device packaging material 10 of the present disclosure contains a polyamide film, and the crystallization index of the polyamide film measured from the outside of the base material layer 1 by the ATR method of Fourier transform infrared spectroscopy is 1.50 or more. The method for measuring the crystallization index of the base material layer 1 of the electrical storage device packaging material 10 of the present disclosure is as follows.

[0021] <Measurement of the crystallization index of the base material layer of the exterior material for an electricity storage device> The exterior material for a power storage device is cut into a 100 mm x 100 mm square to prepare a sample. The surface of the polyamide film located on the outside of the obtained sample is subjected to infrared absorption spectrum measurement using the ATR measurement mode of FT-IR under an environment of a temperature of 25°C and a relative humidity of 50%. As an apparatus, for example, a Nicolet iS10 manufactured by Thermo Fisher Scientific Inc. can be used. From the obtained absorption spectrum, a 1200 cm -1 The peak intensity P near 1370 cm originates from absorption unrelated to crystals. -1The peak intensity Q near the peak intensity P is measured, and the intensity ratio X=P / Q of the peak intensity P to the peak intensity Q is calculated as the crystallization index. When obtaining an electrical storage device packaging material from an electrical storage device to measure the crystallization index of the base material layer, the sample is prepared by obtaining the electrical storage device packaging material from the top or bottom surface, rather than from the heat-sealed portion or side surface of the electrical storage device. (Measurement conditions) Method: Macro ATR method Wavenumber resolution: 8cm -1 Accumulation count: 32 times Detector: DTGS detector ATR prism: Ge Incident angle: 45° Baseline: Wavenumber 1100cm -1 From 1400cm -1 The curve was calculated as a linear approximation between the two. Absorption peak intensity Y 1200 : Wave number 1195cm -1 From 1205cm -1 The maximum peak intensity in the range minus the baseline value Absorption peak intensity Y 1370 : Wave number 1365cm -1 From 1375cm -1 The maximum peak intensity in the range minus the baseline value

[0022] When the outer surface of the electricity storage device packaging material 10 is made up of the polyamide film of the base material layer 1, the crystallization index can be measured directly for the electricity storage device packaging material 10. When the outer surface of the electricity storage device packaging material 10 is not made up of the polyamide film of the base material layer 1, such as when the base material layer 1 has a multilayer structure as described below and a resin film different from the polyamide film (for example, a polyester film) is located outside the polyamide film, or when a surface coating layer 6 described below is laminated on the outside of the base material layer 1, the layer located outside the polyamide film can be removed from the electricity storage device packaging material 10 to expose the surface of the polyamide film, and the crystallization index can be measured.

[0023] In the packaging material 10 for an electricity storage device, the crystallization index may be 1.50 or more, but from the viewpoint of more effectively preventing damage to the packaging material for an electricity storage device during peeling, it is more preferably 1.55 or more, even more preferably 1.60 or more, and particularly preferably 1.65 or more. There are no particular restrictions on the upper limit of the crystallization index, but examples include 2.50 or less and 1.80 or less. Preferred ranges for the crystallization index include, for example, 1.50 to 2.50, 1.60 to 2.50, 1.65 to 2.50, 1.50 to 1.80, 1.60 to 1.80, and 1.65 to 1.80.

[0024] Methods for increasing the crystallization index of the polyamide film contained in the base material layer 1 of the packaging material 10 for an electrical storage device to 1.50 or more include promoting crystallization (promoting the production of α crystals) by adjusting the stretching ratio, heat setting temperature, and even the post-heating temperature and time during the polyamide film manufacturing process.

[0025] 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.

[0026] The substrate layer 1 includes a polyamide film. As described above, the crystallization index of the polyamide film measured from the outside of the substrate layer 1 by the ATR method of Fourier transform infrared spectroscopy is 1.50 or more.

[0027] The polyamide forming the polyamide film may be any polyamide having α crystals, and specific examples thereof include aliphatic polyamides such as nylon 6, nylon 66, nylon 46, and copolymers of nylon 6 and nylon 66. These polyamides may be used alone or in combination of two or more. The polyamide film is preferably a nylon film.

[0028] The polyamide film may be an unstretched film or a stretched film. When the base material layer 1 includes an unstretched film, the unstretched film may be formed by extrusion when laminating the layers of the electrical storage device packaging material 10, or a previously prepared unstretched film may be bonded, or a resin (polyamide) may be applied to form the unstretched film. Examples of methods for applying the resin include roll coating, gravure coating, and extrusion coating. When the base material layer 1 is a stretched film, a previously prepared stretched film is bonded when laminating the layers of the electrical storage device packaging material 10. Examples of stretched films include uniaxially stretched films and biaxially stretched films, and biaxially stretched films are preferred. Examples of stretching methods for forming a biaxially stretched film include sequential biaxial stretching, inflation, and simultaneous biaxial stretching.

[0029] The polyamide film is preferably a biaxially oriented nylon film.

[0030] The electrical storage device packaging material 10 of the present disclosure can be manufactured using, as the base material layer 1, a polyamide film having a crystallization index of 1.50 or more as measured by the ATR method of Fourier transform infrared spectroscopy. Alternatively, the crystallization index can be increased to 1.50 or more by applying heat to the polyamide film during the manufacturing process of the electrical storage device packaging material 10. As will be described in the section "5. Polyamide Film" below, the electrical storage device packaging material 10 of the present disclosure is preferably manufactured using, as the base material layer 1, a polyamide film having a crystallization index of 1.50 or more as measured by the ATR method of Fourier transform infrared spectroscopy. That is, the electrical storage device packaging material 10 of the present disclosure is preferably manufactured by using, as the base material layer 1, a polyamide film whose crystallization index has been adjusted in advance to 1.50 or more, and laminating it with each layer, such as the barrier layer 3 and the heat-sealable resin layer 4. As will be shown in the examples described later, the crystallization index of the polyamide film laminated to the packaging material 10 for an electricity storage device and included in the base material layer 1 can be made higher than that of the polyamide film before it is applied to the packaging material 10 for an electricity storage device.

[0031] The thickness of the polyamide film is preferably about 3 μm or more, more preferably about 10 μm or more, from the viewpoint of more effectively preventing damage to the packaging material for an electricity storage device during the aforementioned peeling, and is also preferably about 50 μm or less, more preferably about 35 μm or less. Preferred ranges include about 3 to 50 μm, about 3 to 35 μm, about 10 to 50 μm, and about 10 to 35 μm, and of these, about 10 to 35 μm is particularly preferred.

[0032] The substrate layer 1 may further include a resin film different from the polyamide film. Examples of resins that form the resin film different from the polyamide film include polyester, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. The resin 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. Among these, polyester is preferred.

[0033] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters containing ethylene terephthalate as the main repeating unit. Specific examples include copolymer polyesters in which ethylene terephthalate as the main repeating unit is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl dicarboxylate), and polyethylene (terephthalate / decane dicarboxylate). These polyesters may be used alone or in combination of two or more. Among these, polyethylene terephthalate and polybutylene terephthalate are preferred.

[0034] The polyester film is preferably a stretched polyester film, more preferably a biaxially stretched polyester film.

[0035] The polyester film is preferably a biaxially oriented polyethylene terephthalate film or a biaxially oriented polybutylene terephthalate film.

[0036] When the base layer 1 further contains a resin film other than the polyamide film, the thickness of the other resin film is not particularly limited as long as it does not impair the effects of the present invention, and is preferably at least about 3 μm, more preferably at least about 10 μm, and is also preferably at most about 50 μm, more preferably at most about 35 μm. Preferred ranges include about 3 to 50 μm, about 3 to 35 μm, about 10 to 50 μm, and about 10 to 35 μm, with about 10 to 35 μm being particularly preferred.

[0037] The base material layer 1 may be a single layer or may be composed of two or more layers as long as it contains a polyamide film, and from the viewpoint of making the packaging material 10 for an electricity storage device thinner, it is preferably a single layer of polyamide film.

[0038] When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or a laminate of two or more resin films formed by co-extrusion of resins. Furthermore, a laminate of two or more resin films formed by co-extrusion of resins may be used as the base material layer 1 without being stretched, or may be uniaxially or biaxially stretched to form the base material layer 1.

[0039] Specific examples of laminates of two or more resin films in the base layer 1 include laminates of polyester film and nylon film, and laminates of two or more nylon film layers. A laminate of stretched nylon film and stretched polyester film, or a laminate of two or more stretched nylon film layers is preferred. For example, when the base layer 1 is a laminate of two resin films, a laminate of polyamide resin film and polyamide resin film, or a laminate of polyester resin film and polyamide resin film is preferred, and 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.

[0040] When the base layer 1 is a laminate of two or more resin film layers, the two or more resin film layers may be laminated via an adhesive. Examples of preferred adhesives include those similar to those exemplified for adhesive layer 2 described below. The method for laminating two or more resin film layers is not particularly limited, and known methods can be used, such as dry lamination, sandwich lamination, extrusion lamination, and thermal lamination, with dry lamination being preferred. When laminating using the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. In this case, the thickness of the adhesive may be, for example, about 2 to 5 μm. Alternatively, an anchor coat layer may be formed on the resin film before lamination. Examples of the anchor coat layer include those similar to those exemplified for adhesive layer 2 described below. In this case, the thickness of the anchor coat layer may be, for example, about 0.01 to 1.0 μm.

[0041] 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.

[0042] 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.

[0043] 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

[0044] 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.

[0045] The total thickness of the substrate layer 1 is not particularly limited as long as it functions as a substrate, but is, for example, about 3 to 50 μm, and preferably about 10 to 35 μm.

[0046] [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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] [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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] The type of pigment is not particularly limited as long as it does not impair the adhesiveness of the adhesive layer 2. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments. Examples of inorganic pigments include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, iron-based, and copper-based pigments. Other examples include mica fine powder and fish scale foil. Pigments can be used alone or in combination of two or more types, such as a combination of an organic pigment and an inorganic pigment.

[0056] 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.

[0057] 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.

[0058] 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 8 to 40 mass %.

[0059] 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.

[0060] [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.

[0061] 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.

[0062] Specific examples of the colorant contained in the colored layer include the same as those exemplified in the section [Adhesive layer 2].

[0063] [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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] In the case of a metal foil, the thickness of the barrier layer 3 is sufficient as long as it at least functions as a barrier layer that prevents moisture from penetrating, and may be, for example, about 9 to 200 μm. The thickness of the barrier layer 3 is, for example, preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less, and preferably about 10 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. Preferred thickness ranges 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, with about 25 to 40 μm being particularly preferred. When the barrier layer 3 is made of an aluminum alloy foil, the above-mentioned ranges are particularly preferred. Furthermore, particularly when the barrier layer 3 is composed of a stainless steel foil, the upper limit of the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less, and the lower limit is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred thickness ranges include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0069] 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.

[0070] 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.

[0071] 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 Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, or Zn (zinc) 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.

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] 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, 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] The composition of the corrosion-resistant film can be analyzed using, for example, time-of-flight secondary ion mass spectrometry.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] [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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount of the lubricant is not particularly limited. However, from the viewpoint of improving the formability of the packaging material for an electricity storage device, the amount of the lubricant is preferably 10 to 50 mg / m 2 about 15 to 40 mg / m 2 The degree of

[0095] 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.

[0096] The thickness of the heat-sealable resin layer 4 is not particularly limited as long as it can heat-seal the heat-sealable resin layers to each other and function to seal the electricity storage device element, but may be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described below is 10 μm or more, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 5 described below is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0097] [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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] The upper limit of the thickness of adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, or about 5 μm or less, and the lower limit is preferably about 0.1 μm or more, or about 0.5 μm or more, and the thickness range is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, or about 0.5 to 5 μm. More specifically, in the case of an adhesive such as those exemplified for adhesive layer 2 or a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably about 1 to 10 μm, more preferably about 1 to 5 μm. Furthermore, when a resin exemplified for the heat-fusible resin layer 4 is used, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When the adhesive layer 5 is an adhesive exemplified for the adhesive layer 2 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed, for example, by applying the resin composition and curing it by heating or the like. When a resin exemplified for the heat-fusible resin layer 4 is used, the heat-fusible resin layer 4 and the adhesive layer 5 can be formed, for example, by extrusion molding.

[0114] [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.

[0115] The surface coating layer 6 can be formed from a resin such as polyvinylidene chloride, polyester, polyurethane, acrylic resin, or epoxy resin.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 3. Manufacturing method for exterior materials for power storage devices The method for producing an 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 disclosure are stacked, and examples include a method comprising a step of stacking, in this order from the outside, at least a substrate layer 1, a barrier layer 3, and a thermally adhesive resin layer 4. Specifically, the method for producing an electrical storage device packaging material of the present disclosure comprises a step of producing a laminate in which, in this order from the outside, at least a substrate layer, a barrier layer, and a thermally adhesive resin layer are stacked, the substrate layer includes a polyamide film, and the crystallization index of the polyamide film measured from the outside of the substrate layer by the ATR method of Fourier transform infrared spectroscopy is 1.50 or more.

[0124] An example of a method for manufacturing an exterior material for an electricity storage device according to the present disclosure is as follows: First, a laminate (hereinafter, sometimes referred to as "laminate A") is formed in which a base layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order. Specifically, 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, the surface of which has been chemically treated as necessary, by a coating method such as gravure coating or roll coating, and then dried, followed by laminating the barrier layer 3 or base layer 1 and curing the adhesive layer 2.

[0125] 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.

[0126] 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.

[0127] As described above, a laminate is formed which includes, from the outside, an optional surface coating layer 6 / a substrate layer 1 / an optional adhesive layer 2 / a barrier layer 3 / an optional adhesive layer 5 / a heat-sealable resin layer 4. 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.

[0128] 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.

[0129] 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.

[0130] 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).

[0131] 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.

[0132] Electricity storage devices are generally fixed to the housings of various products via double-sided tape or adhesive. That is, the exterior material 10 for an electricity storage device according to the present disclosure is fixed to the housings of various products via double-sided tape or adhesive. The material of the housing varies depending on the type of product, and is diverse, including metals such as stainless steel, aluminum alloy, and nickel alloy, plastics such as polyolefin, polyamide, polyester, polyimide, and polystyrene, and glass.

[0133] The adhesive strength between the electricity storage device and the housing is adjusted to, for example, a level that allows the electricity storage device to be peeled off from the housing. The peel strength between the electricity storage device and the housing is preferably fixed using double-sided tape that has a peel strength of about 5 to 15 N / 7.5 mm against a stainless steel plate, as measured in the (Measurement of Peel Strength of Double-Sided Tape) method described below. The exterior material 10 for an electricity storage device can be suitably used for an electricity storage device that is fixed to a housing using double-sided tape that has a peel strength of about 5 to 15 N / 7.5 mm against the housing.

[0134] 5. Polyamide film The polyamide film of the present disclosure is a polyamide film for use in the base layer of a packaging material for an electricity storage device, which is composed of a laminate including at least a base layer, a barrier layer, and a heat-sealable resin layer, and has a crystallization index of 1.50 or more as measured by the ATR method of Fourier transform infrared spectroscopy. Details of the packaging material for an electricity storage device 10 are as described above.

[0135] By using the polyamide film of the present disclosure as the base layer 1 of the electrical storage device packaging material, the crystallization index of the polyamide film of the base layer 1 of the electrical storage device packaging material 10 can be suitably set to 1.50 or more, effectively preventing damage to the electrical storage device packaging material during the aforementioned peeling. That is, it is preferable to manufacture the electrical storage device packaging material 10 of the present disclosure by using the polyamide film of the present disclosure, whose crystallization index has been adjusted to 1.50 or more in advance, as the base layer 1 and laminating it with each layer, such as the barrier layer 3 and the heat-sealable resin layer 4. As described above, the crystallization index of the polyamide film laminated to the electrical storage device packaging material 10 and included in the base layer 1 can be made higher than that of the polyamide film before being applied to the electrical storage device packaging material 10. Specifically, the crystallization index can also be increased by applying heat to the polyamide film during the manufacturing process of the electrical storage device packaging material 10.

[0136] For polyamide films of the present disclosure, the method for measuring the crystallization index is as follows.

[0137] <Measurement of the crystallization index of polyamide film> Polyamide film is cut into a 100 mm x 100 mm square to prepare a sample. The surface of the obtained sample is subjected to infrared absorption spectrum measurement using the ATR measurement mode of FT-IR under an environment of a temperature of 25°C and a relative humidity of 50%. For example, a Nicolet iS10 manufactured by Thermo Fisher Scientific Inc. can be used. From the obtained absorption spectrum, a 1200 cm peak attributable to the absorption of α-crystals of nylon is observed. -1 The peak intensity P near 1370 cm originates from absorption unrelated to crystals.-1 The peak intensity Q in the vicinity of the peak intensity P is measured, and the intensity ratio X=P / Q of the peak intensity P to the peak intensity Q is calculated as the crystallization index. (Measurement conditions) Method: Macro ATR method Wavenumber resolution: 8cm -1 Accumulation count: 32 times Detector: DTGS detector ATR prism: Ge Incident angle: 45° Baseline: Wavenumber 1100cm -1 From 1400cm -1 The curve was calculated as a linear approximation between the two. Absorption peak intensity Y 1200 : Wave number 1195cm -1 From 1205cm -1 The maximum peak intensity in the range minus the baseline value Absorption peak intensity Y 1370 : Wave number 1365cm -1 From 1375cm -1 The maximum peak intensity in the range minus the baseline value

[0138] In the polyamide film of the present disclosure, the crystallization index may be 1.50 or more, but from the viewpoint of more effectively preventing damage to the packaging material for an electricity storage device during peeling, it is more preferably 1.55 or more, even more preferably 1.60 or more, and particularly preferably 1.65 or more. The upper limit of the crystallization index is not particularly limited, but may be, for example, 2.50 or less or 1.80 or less. Preferred ranges of the crystallization index include, for example, 1.50 to 2.50, 1.60 to 2.50, 1.65 to 2.50, 1.50 to 1.80, 1.60 to 1.80, and 1.65 to 1.80.

[0139] Specific examples of polyamides forming the polyamide film are as explained in the section on the base material layer 1 of the packaging material 10 for an electricity storage device. The polyamide 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.

[0140] The polyamide film is preferably a biaxially oriented nylon film.

[0141] The thickness of the polyamide film is preferably about 3 μm or more, more preferably about 10 μm or more, from the viewpoint of more effectively preventing damage to the packaging material for an electricity storage device during the aforementioned peeling, and is also preferably about 50 μm or less, more preferably about 35 μm or less. Preferred ranges include about 3 to 50 μm, about 3 to 35 μm, about 10 to 50 μm, and about 10 to 35 μm, and of these, about 10 to 35 μm is particularly preferred.

[0142] 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 interior of the polyamide film. Only one type of additive may be used, or two or more types may be mixed and used. Details of the additives are as described in the section on the base material layer 1 of the exterior material 10 for an electricity storage device. [Example]

[0143] 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.

[0144] <Manufacturing of exterior materials for energy storage devices> Examples 1-3 and Comparative Examples 1-2 A stretched nylon (ONy) film (25 μm thick) was prepared as the substrate layer. As described below, the stretched nylon films used in Examples 1-3 and Comparative Examples 1-2 were adjusted to the crystallization index values ​​shown in Table 1 by changing the stretch ratio and heat setting temperature. The stretched nylon film was coated with erucic acid amide as a lubricant. An aluminum alloy foil (JIS H4160:1994 A8021H-O (40 μm thick)) was prepared as the barrier layer. Next, an adhesive (two-component urethane adhesive) was applied to one side of the aluminum alloy foil and dried. Next, the adhesive on the barrier layer and the substrate layer were laminated by dry lamination, followed by aging treatment to produce a substrate layer (25 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (40 μm thick) laminate. Both sides of the aluminum alloy foil were subjected to a chemical conversion treatment. The chemical conversion treatment of aluminum alloy foil is carried out using a treatment solution consisting of phenolic resin, chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m 2 (dry mass) by applying the coating solution to both sides of the aluminum alloy foil by roll coating, and baking the coating solution.

[0145] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 23 μm) and random polypropylene as a heat-sealable resin layer (thickness 23 μm) were co-extruded onto the barrier layer of each of the laminates obtained above, thereby laminating the adhesive layer / heat-sealable resin layer on top of the barrier layer, and aging was performed to obtain a laminate (total thickness 114 μm) laminated from the outside in the following order: base layer (thickness 25 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (23 μm) / heat-sealable resin layer (23 μm).

[0146] Example 4 An oriented nylon (ONy) film (20 μm thick) was prepared as the substrate layer. As described below, the stretched nylon film used in Example 4 had its crystallization index adjusted to the values ​​listed in Table 1 by changing the stretch ratio and heat setting temperature. The stretched nylon film had 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. An aluminum alloy foil (JIS H4160:1994 A8021H-O (35 μm thick)) was prepared as the barrier layer. Next, an adhesive (a two-component urethane adhesive) was applied to one side of the aluminum alloy foil and dried. Next, the adhesive on the barrier layer and the substrate layer were laminated by dry lamination, followed by aging treatment to produce a substrate layer (20 μm thick), adhesive layer (3 μm thick after curing), and barrier layer (35 μm thick) laminate. Both sides of the aluminum alloy foil are chemically treated. The chemical treatment of the aluminum alloy foil is carried out by applying a treatment solution consisting of phenolic resin, a chromium fluoride compound, and phosphoric acid to a coating amount of chromium of 10 mg / m 2 (dry mass) by applying the coating solution to both sides of the aluminum alloy foil by roll coating, and baking the coating solution.

[0147] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 15 μm) and random polypropylene as a heat-sealable resin layer (thickness 15 μm) were co-extruded onto the barrier layer of each of the laminates obtained above, thereby laminating the adhesive layer / heat-sealable resin layer on top of the barrier layer, and aging was performed to obtain a laminate (total thickness 88 μm) in which, from the outside, the substrate layer (thickness 20 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (15 μm) / heat-sealable resin layer (15 μm) were laminated.

[0148] Example 5 An oriented nylon (ONy) film (20 μm thick) was prepared as the substrate layer. The oriented nylon film used in Example 5 was the same as that used in Example 4. The oriented nylon film had 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. An aluminum alloy foil (JIS H4160:1994 A8021H-O (30 μm thick)) was prepared as the barrier layer. Next, an adhesive (a two-component urethane adhesive) was applied to one side of the aluminum alloy foil and dried. Next, the adhesive on the barrier layer and the substrate layer were laminated by dry lamination, followed by aging treatment to produce a substrate layer (20 μm thick), adhesive layer (3 μm thick after curing), and barrier layer (30 μm thick) laminate. Both sides of the aluminum alloy foil were subjected to a chemical conversion treatment. The chemical conversion treatment of aluminum alloy foil is carried out using a treatment solution consisting of phenolic resin, chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m 2 (dry mass) by applying the coating solution to both sides of the aluminum alloy foil by roll coating, and baking the coating solution.

[0149] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 14 μm) and random polypropylene as a heat-sealable resin layer (thickness 10 μm) were co-extruded onto the barrier layer of each laminate obtained above, thereby laminating the adhesive layer / heat-sealable resin layer on top of the barrier layer, and aging was performed to obtain a laminate (total thickness 77 μm) laminated from the outside in the following order: base layer (thickness 20 μm) / adhesive layer (3 μm) / barrier layer (30 μm) / adhesive layer (14 μm) / heat-sealable resin layer (10 μm).

[0150] Example 6 A laminate (total thickness 114 μm) having, from outside to inside, the substrate layer (thickness 25 μm), adhesive layer (3 μm), barrier layer (40 μm), adhesive layer (23 μm), and heat-sealable resin layer (23 μm) was obtained in the same manner as in Example 1, except that a stretched nylon (ONy) film having a coating layer (polyester polyurethane applied to a thickness of 300 nm or less) on the surface on the barrier layer side was used as the substrate layer.

[0151] Example 7 An oriented nylon (ONy) film (thickness: 20 μm) was prepared as the substrate layer. The oriented nylon film used in Example 7 was the same as that used in Example 4. An aluminum alloy foil (JIS H4160:1994 A8021H-O (thickness: 35 μm)) was prepared as the barrier layer. Next, the barrier layer and the substrate layer were laminated by dry lamination using an adhesive (a two-component urethane adhesive containing carbon black), and then aging treatment was performed to produce a laminate of substrate layer (thickness: 20 μm) / adhesive layer (thickness: 3 μm after curing) / barrier layer (thickness: 35 μm). Both sides of the aluminum alloy foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum alloy foil was performed using a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m. 2 (dry mass) by applying the coating solution to both sides of the aluminum alloy foil by roll coating, and baking the coating solution.

[0152] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 15 μm) and random polypropylene as a heat-sealable resin layer (thickness 15 μm) were co-extruded onto the barrier layer of each of the laminates obtained above, thereby laminating the adhesive layer / heat-sealable resin layer on top of the barrier layer, thereby obtaining a laminate in which the substrate layer (thickness 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. Next, a two-component urethane resin containing silica particles and resin beads was applied to the surface of the stretched nylon film of the obtained laminate to form a matte layer as a surface coating layer to a thickness of 3 μm, and aging was performed to obtain a laminate (total thickness 91 μm) consisting of, from the outside, a surface coating layer (thickness 3 μm), a base layer (thickness 20 μm), an adhesive layer (3 μm), a barrier layer (35 μm), an adhesive layer (15 μm), and a heat-sealable resin layer (15 μm).

[0153] Example 8 An oriented nylon (ONy) film (thickness: 20 μm) was prepared as the substrate layer. The oriented nylon film used in Example 8 was the same as that used in Example 4. An aluminum alloy foil (JIS H4160:1994 A8021H-O (thickness: 40 μm)) was prepared as the barrier layer. Next, an adhesive (two-component urethane adhesive) was applied to one side of the aluminum alloy foil and dried. Next, the adhesive on the barrier layer and the substrate layer were laminated by a dry lamination method, and then aging treatment was performed to produce a laminate of substrate layer (thickness: 20 μm) / adhesive layer (thickness: 3 μm after curing) / barrier layer (thickness: 40 μm). Both sides of the aluminum alloy foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum alloy foil was performed using a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a chromium coating amount of 10 mg / m 2 (dry mass) by applying the coating solution to both sides of the aluminum alloy foil by roll coating, and baking the coating solution.

[0154] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 14 μm) and random polypropylene as a heat-sealable resin layer (thickness 10 μm) were co-extruded onto the barrier layer of each of the laminates obtained above, thereby laminating the adhesive layer / heat-sealable resin layer on top of the barrier layer, and aging was performed to obtain a laminate (total thickness 87 μm) in which, from the outside, the substrate layer (thickness 20 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (14 μm) / heat-sealable resin layer (10 μm) were laminated.

[0155] Example 9 An oriented nylon (ONy) film (thickness: 20 μm) was prepared as the substrate layer. The oriented nylon film used in Example 9 was the same as that used in Example 4. An aluminum alloy foil (JIS H4160:1994 A8021H-O (thickness: 40 μm)) was prepared as the barrier layer. Next, the barrier layer and the substrate layer were laminated by dry lamination using an adhesive (a two-component urethane adhesive containing carbon black), and then aging treatment was performed to produce a laminate of substrate layer (thickness: 20 μm) / adhesive layer (thickness: 3 μm after curing) / barrier layer (thickness: 40 μm). Both sides of the aluminum alloy foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum alloy foil was performed using a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m. 2 (dry mass) by applying the coating solution to both sides of the aluminum alloy foil by roll coating, and baking the coating solution.

[0156] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 14 μm) and random polypropylene as a heat-sealable resin layer (thickness 10 μm) were co-extruded onto the barrier layer of each of the laminates obtained above, thereby laminating the adhesive layer / heat-sealable resin layer on top of the barrier layer, thereby obtaining a laminate in which the substrate layer (thickness 20 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (14 μm) / heat-sealable resin layer (10 μm) were laminated in this order. Next, a two-component urethane resin containing silica particles and resin beads was applied to the surface of the stretched nylon film of the obtained laminate to a thickness of 3 μm to form a matte layer as a surface coating layer, and the laminate was aged to obtain a laminate (total thickness 90 μm) consisting of, from the outside, a surface coating layer (thickness 3 μm), a base layer (thickness 20 μm), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (14 μm), and a heat-sealable resin layer (10 μm).

[0157] Example 10 An oriented nylon (ONy) film (thickness: 20 μm) was prepared as the substrate layer. The oriented nylon film used in Example 10 was the same as that used in Example 4. An aluminum alloy foil (JIS H4160:1994 A8021H-O (thickness: 40 μm)) was prepared as the barrier layer. Next, an adhesive (two-component urethane adhesive) was applied to one side of the aluminum alloy foil and dried. Next, the adhesive on the barrier layer and the substrate layer were laminated by a dry lamination method, and then aging treatment was performed to produce a laminate of substrate layer (thickness: 20 μm) / adhesive layer (thickness: 3 μm after curing) / barrier layer (thickness: 40 μm). Both sides of the aluminum alloy foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum alloy foil was performed using a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a chromium coating amount of 10 mg / m 2 (dry mass) by applying the coating solution to both sides of the aluminum alloy foil by roll coating, and baking the coating solution.

[0158] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 15 μm) and random polypropylene as a heat-sealable resin layer (thickness 15 μm) were co-extruded onto the barrier layer of each laminate obtained above, thereby laminating the adhesive layer / heat-sealable resin layer on top of the barrier layer, and aging was performed to obtain a laminate (total thickness 93 μm) laminated with, from the outside, base layer (thickness 20 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (15 μm) / heat-sealable resin layer (15 μm).

[0159] Example 11 An oriented nylon (ONy) film (thickness: 20 μm) was prepared as the substrate layer. The oriented nylon film used in Example 11 was the same as that used in Example 4. An aluminum alloy foil (JIS H4160:1994 A8021H-O (thickness: 40 μm)) was prepared as the barrier layer. Next, the barrier layer and the substrate layer were laminated by dry lamination using an adhesive (a two-component urethane adhesive containing carbon black), and then aging treatment was performed to produce a laminate of substrate layer (thickness: 20 μm) / adhesive layer (thickness: 3 μm after curing) / barrier layer (thickness: 40 μm). Both sides of the aluminum alloy foil were subjected to chemical conversion treatment. The chemical conversion treatment of the aluminum alloy foil was performed using a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m. 2 (dry mass) by applying the coating solution to both sides of the aluminum alloy foil by roll coating, and baking the coating solution.

[0160] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 14 μm) and random polypropylene as a heat-sealable resin layer (thickness 10 μm) were co-extruded onto the barrier layer of each of the laminates obtained above, thereby laminating the adhesive layer / heat-sealable resin layer on top of the barrier layer, thereby obtaining a laminate in which the substrate layer (thickness 20 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (15 μm) / heat-sealable resin layer (15 μm) were laminated in this order. Next, a two-component urethane resin containing silica particles and resin beads was applied to the surface of the stretched nylon film of the obtained laminate to form a matte layer as a surface coating layer to a thickness of 3 μm, and aging was performed to obtain a laminate (total thickness 96 μm) consisting of, from the outside, a surface coating layer (thickness 3 μm), a base layer (thickness 20 μm), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (15 μm), and a heat-sealable resin layer (15 μm).

[0161] <Measurement of the crystallization index of the base material layer of the exterior material for an electricity storage device> The exterior material for a power storage device was cut into a 100 mm × 100 mm square to prepare a sample. The surface of the stretched nylon film located on the outside of the obtained sample was subjected to infrared absorption spectrum measurement under an environment of a temperature of 25 ° C and a relative humidity of 50 % using an ATR measurement mode of a Nicolet iS10 FT-IR (manufactured by Thermo Fisher Scientific Co., Ltd.). From the obtained absorption spectrum, a 1200 cm peak attributable to the absorption of α-crystals of nylon was observed. -1 The peak intensity P near 1370 cm originates from absorption unrelated to crystals. -1 The peak intensity Q near the peak was measured, and the intensity ratio X = P / Q of the peak intensity P to the peak intensity Q was calculated as the crystallization index. For Examples 7, 9, and 11, the measurement was carried out before the surface coating layer was applied. The results are shown in Table 1. (Measurement conditions) Method: Macro ATR method Wavenumber resolution: 8cm -1 Accumulation count: 32 times Detector: DTGS detector ATR prism: Ge Incident angle: 45° Baseline: Wavenumber 1100cm -1 From 1400cm -1 The curve was calculated as a linear approximation between the two. Absorption peak intensity Y 1200 : Wave number 1195cm -1 From 1205cm -1 The maximum peak intensity in the range minus the baseline value Absorption peak intensity Y 1370 : Wave number 1365cm -1 From 1375cm -1 The maximum peak intensity in the range minus the baseline value

[0162] <Measurement of the crystallization index of oriented nylon film> The stretched nylon film used as the base layer of the exterior material for the power storage device was cut into a 100 mm × 100 mm square to prepare a sample. The surface of the obtained sample was subjected to infrared absorption spectrum measurement under an environment of a temperature of 25 ° C and a relative humidity of 50% using the ATR measurement mode of a Nicolet iS10 FT-IR manufactured by Thermo Fisher Scientific Co., Ltd. The obtained absorption spectrum showed a 1200 cm -1 The peak intensity P near 1370 cm originates from absorption unrelated to crystals. -1 The peak intensity Q near the peak intensity P was measured, and the intensity ratio X=P / Q of the peak intensity P to the peak intensity Q was calculated as the crystallization index. The results are shown in Table 1. (Measurement conditions) Method: Macro ATR method Wavenumber resolution: 8cm -1 Accumulation count: 32 times Detector: DTGS detector ATR prism: Ge Incident angle: 45° Baseline: Wavenumber 1100cm -1 From 1400cm -1 The curve was calculated as a linear approximation between the two. Absorption peak intensity Y 1200 : Wave number 1195cm -1 From 1205cm -1The maximum peak intensity in the range minus the baseline value Absorption peak intensity Y 1370 : Wave number 1365cm -1 From 1375cm -1 The maximum peak intensity in the range minus the baseline value

[0163] <Electricity storage device peeling test> The peel test for the electricity storage device was performed according to the following procedure. This procedure will be explained with reference to FIGS. 5 to 8. First, the procedure for preparing a sample used in the peel test for the electricity storage device will be explained with reference to FIG. 5. As shown in FIG. 5a, the exterior material for the electricity storage device was cut into a rectangle measuring 200 mm in length (MD) and 90 mm in width (TD). Next, using a molding die (female die) with an opening of 55 mm in length (MD) × 32 mm in width (TD) and a corresponding molding die (male die), the exterior material for the electricity storage device was cold-molded to a depth of 5.0 mm from the heat-sealable resin layer side at a position 15 mm away from the short side of the exterior material for the electricity storage device, forming a recess M (the area surrounded by the dashed line in FIG. 5a). Next, an acrylic plate measuring 55 mm in length, 32 mm in width, and 5 mm in thickness was inserted into the recess M (FIGS. 5b and 5c). Next, the molded electrical storage device packaging material was folded in half in the TD direction at crease P (along the short side of recess M) with recess M facing inward (Fig. 5d). Next, along the periphery of recess M, the overlapping portions of the thermally adhesive resin layers were heat-sealed (190°C, 3 seconds, surface pressure 1 MPa) at three locations along the MD and TD to seal recess M (Fig. 5e). In Fig. 5e, the colored area S represents the heat-sealed portion. Next, as shown in Fig. 5f, the sample was trimmed to a size of 60 mm in length (MD) and 37 mm in width (TD) along recess M to prepare sample 12 for use in peel testing of electrical storage devices. Fig. 6 shows a side view (Fig. 6a) and a plan view (Fig. 6b) of sample 12.

[0164] Next, as shown in the schematic diagram of Fig. 7, three pieces of double-sided tape (7.5 mm wide, 55 mm long) were attached to both ends and the center of the flat surface of sample 12 (the surface opposite to the surface on which recesses M were formed) along the machine direction (MD). The peel strength of the double-sided tape to the object was measured using the method described below.

[0165] Next, Sample 12 with the double-sided tape attached was attached to a stainless steel plate and cured in an environment of 60°C for 24 hours. The stainless steel plate served as a housing to which the electricity storage device was fixed with the double-sided tape. Next, as shown in the schematic diagram of Figure 8, Sample 12 was carefully peeled off from the stainless steel plate using a metal spatula, and the peeled Sample 12 was visually inspected for the presence or absence of holes. Three samples for each type were evaluated in the electricity storage device peel test according to the following criteria. As shown in Figure 8, the electricity storage device was peeled off by applying force from the lateral direction (TD) of Sample 12. The results are shown in Table 1. A: All three samples were hole-free. B: One or two samples had holes. C: All three samples had holes.

[0166] [Table 1]

[0167] The electrical storage device packaging materials of Examples 1 to 11 are composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, the base material layer including a polyamide film, and the polyamide film has a crystallization index of 1.50 or more as measured from the outside of the base material layer by the ATR method of Fourier transform infrared spectroscopy. Furthermore, the polyamide film used in the base material layer of the electrical storage device packaging materials of Examples 1 to 11 has a crystallization index of 1.50 or more as measured by the ATR method of Fourier transform infrared spectroscopy. It can be seen that the electrical storage device packaging materials of Examples 1 to 11 effectively prevent damage to the electrical storage device packaging materials when an electrical storage device fixed with double-sided tape or the like is peeled off from a housing.

[0168] The difference between the crystallization index measured for the base layer of the electrical storage device packaging material and the crystallization index measured for the stretched nylon film is thought to be due to the influence of aging of the electrical storage device packaging material. The stretched nylon films used in Comparative Examples 1 and 2 had crystallization index values ​​significantly smaller than those of Examples 1 to 11, but the values ​​measured after being used as the base layer of the electrical storage device packaging material were significantly larger than the values ​​measured in the stretched nylon film state. However, in Comparative Examples 1 and 2, the crystallization index of the polyamide film measured from the outside of the base layer was not increased to 1.50 or higher by aging the electrical storage device packaging material, and the peel test evaluation of the electrical storage device was inferior to that of Examples 1 to 11.

[0169] (Measurement of peel strength of double-sided tape) The following were prepared: the exterior packaging materials for electricity storage devices (15 mm long x 70 mm wide) of Examples 1 to 11; the double-sided tape (7.5 mm long x 60 mm wide) used in the <Electricity Storage Device Peel Test>; aluminum foil (35 μm thick x 15 mm long x 150 mm wide); a double-sided adhesive tape for fixing (5 mm long x 60 mm wide); and an acrylic plate (3 mm thick x 50 mm long x 70 mm wide). First, one side of the double-sided tape was bonded to the surface of the stretched nylon film side of the exterior packaging material for electricity storage devices (the surface of the coating layer on the stretched nylon film for Examples 4 and 5; the surface of the surface coating layer on the stretched nylon film for Examples 7, 9, and 11). Aluminum foil was then bonded to the other side of the double-sided tape, and a 2 kg roller was rolled back and forth over the aluminum foil to obtain a laminate P. Finally, one side of the double-sided adhesive tape for fixing was bonded to an acrylic plate to obtain a laminate Q. Furthermore, the surface of the heat-fusible resin layer of the electricity storage device exterior material of the laminate P was attached to the other side of the fixing double-sided adhesive tape of the laminate Q, and pressed down by hand to obtain a laminate R in which an acrylic plate, fixing double-sided adhesive tape, electricity storage device exterior material, double-sided tape, and aluminum foil were laminated in that order, and this was designated as test sample M. Test sample M was stored in an environment at a temperature of 60°C for 24 hours. Next, the stretched nylon film surface of the electricity storage device exterior material and the end of the double-sided tape were peeled off by about 1 mm to provide a trigger point for measuring peel strength. Next, the acrylic plate of test sample M was fixed, and a tensile tester (Shimadzu Corporation, AG-Xplus (trade name)) was used to pull the aluminum foil at a pull angle of 180°, a peel rate of 300 mm / min, and a peel distance of 50 mm or more. The aluminum foil was peeled at the interface between the stretched nylon film surface of the electrical storage device exterior material and the double-sided tape (from the aforementioned starting point). The peel strength was calculated from the average of five peel strengths: peel strengths at peel distances of 10 mm, 20 mm, 30 mm, and 40 mm, and the maximum peel strength between 10 and 40 mm. This was used as the peel strength (peel strength of the double-sided tape to the stretched nylon film (N / 7.5 mm)). The results are shown in Table 2.

[0170] Next, a stainless steel plate (3 mm thick × 50 mm long × 70 mm wide) and double-sided tape (7.5 mm long × 60 mm wide) were prepared for use in the <Peel Test for Electricity Storage Device>. One side of the double-sided tape was attached to the surface of the stainless steel plate, and aluminum foil was then attached to the other side of the double-sided tape. A 2 kg roller was rolled back and forth over the aluminum foil to obtain a laminate, designated Test Sample N. Test Sample N was stored in an environment at 60°C for 24 hours. Next, the edge of the double-sided tape was peeled approximately 1 mm from the surface of the stainless steel plate to provide a trigger point for measuring peel strength. Next, the stainless steel plate of test sample N was fixed, and the aluminum foil was pulled using a tensile tester (Shimadzu Corporation, AG-Xplus (trade name)) at a pulling angle of 180°, a peel rate of 300 mm / min, and a peel distance of at least 50 mm. The aluminum foil was peeled at the interface between the stainless steel plate surface and the double-sided tape (from the aforementioned peel trigger point). The peel strength was calculated from the average of five peel strengths: peel strengths at peel distances of 10 mm, 20 mm, 30 mm, and 40 mm, and the maximum peel strength between 10 and 40 mm. This was used as the peel strength (peel strength of the double-sided tape to the stainless steel plate (N / 7.5 mm)). The results are shown in Table 2.

[0171] [Table 2]

[0172] As is clear from the results shown in Table 2, the peel strength of the double-sided tape used in the <Power Storage Device Peel Test> was comparable to that of the stretched nylon film and the stainless steel plate.

[0173] As described above, the present disclosure provides the following aspects of the invention. Item 1. The device is composed of a laminate including, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer, the substrate layer includes a polyamide film, An outer casing material for an electricity storage device, wherein the polyamide film has a crystallization index of 1.50 or more as measured from the outside of the base layer by an ATR method of Fourier transform infrared spectroscopy. Item 2. The packaging material for an electricity storage device according to Item 1, further comprising an adhesive layer between the base layer and the barrier layer. Item 3. The packaging material for an electricity storage device according to Item 1 or 2, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer. Item 4. The method includes a step of obtaining a laminate in which at least a base layer, a barrier layer, and a thermally adhesive resin layer are laminated in this order from the outside, the substrate layer includes a polyamide film, A method for producing an exterior material for an electricity storage device, wherein the polyamide film has a crystallization index of 1.50 or more as measured from the outside of the base layer by an ATR method of Fourier transform infrared spectroscopy. Item 5. 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 3. Item 6. A polyamide film for use in a base material layer of an electrical storage device packaging material composed of a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer, The polyamide film has a crystallization index of 1.50 or more as measured by the ATR method of Fourier transform infrared spectroscopy. [Explanation of symbols]

[0174] 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

Claims

1. The laminate is composed of at least a base layer, a barrier layer, and a heat-sealable resin layer, in this order from the outside, the substrate layer includes a polyamide film, the polyamide film is a laminate of two or more nylon films, An outer casing material for an electricity storage device, wherein the polyamide film has a crystallization index of 1.50 or more as measured from the outside of the base material layer by an ATR method of Fourier transform infrared spectroscopy.

2. The packaging material for an electricity storage device according to claim 1 , wherein the polyamide film has a thickness of 50 μm or less (excluding 35 μm or less).

3. The packaging material for an electricity storage device according to claim 1 or 2, further comprising an adhesive layer between the base material layer and the barrier layer.

4. The packaging material for an electricity storage device according to any one of claims 1 to 3, further comprising an adhesive layer between the barrier layer and the heat-sealable resin layer.

5. The method includes a step of obtaining a laminate in which at least a base layer, a barrier layer, and a thermally adhesive resin layer are laminated in this order from the outside, the substrate layer includes a polyamide film, the polyamide film is a laminate of two or more nylon films, A method for producing an exterior material for an electricity storage device, wherein the polyamide film has a crystallization index of 1.50 or more as measured from the outside of the base material layer by an ATR method of Fourier transform infrared spectroscopy.

6. An electricity storage device, wherein 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 claims 1 to 4.

7. A polyamide film for use in a substrate layer of an exterior packaging material for an electricity storage device, the exterior packaging material comprising a laminate including at least a substrate layer, a barrier layer, and a heat-sealable resin layer, the polyamide film is a laminate of two or more nylon films, The polyamide film has a crystallization index of 1.50 or more as measured by the ATR method of Fourier transform infrared spectroscopy.

Images