Outer packaging material for electric storage device, method for manufacturing the same, electric storage device, and polyamide film

Abstract

Provided is an outer packaging material for an electrical storage device, which can suppress breakage of the outer packaging material for the electrical storage device when the electrical storage device, which is fixed to a housing by a double-sided tape or the like, is peeled from the housing. The outer packaging material for the electrical storage device is composed of a laminate having at least a base material layer, a barrier layer, and a heat-fusible resin layer in this order from the outside, and the base material layer contains a polyamide film, and a crystallization index of the polyamide film, measured from the outside of the base material layer by ATR method of Fourier transform infrared spectroscopy, is 1.50 or greater.

Description

[0001] This case is filed on the date of application. May 18, 2020 Application number is 202080036390.1 ,

[0002] The invention is titled " Packaging materials for energy storage devices, their manufacturing methods, energy storage devices and polyamide films "Application for division of cases" Technical Field

[0003] This invention relates to outer packaging materials for energy storage devices, methods for manufacturing such materials, energy storage devices, and polyamide films. Background Technology

[0004] Currently, various types of energy storage devices have been developed. In all these devices, outer packaging materials have become indispensable for encapsulating components such as electrodes and electrolytes. Currently, metal packaging materials are commonly used for the outer packaging of energy storage devices.

[0005] On the other hand, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, computers, cameras, mobile phones, and other devices, there is a growing demand for various shapes, as well as thinner and lighter designs, for energy storage devices. However, the commonly used metal packaging materials for energy storage devices are difficult to adapt to the diversity of shapes and have limitations in achieving lightweight design.

[0006] Therefore, in recent years, as an outer packaging material for energy storage devices that is easy to process into various shapes and can be made thin and lightweight, a film-like laminate having a substrate layer / barrier layer / thermally bondable resin layer stacked in sequence has been proposed (see, for example, Patent Document 1).

[0007] In the outer packaging material for such energy storage devices, a recess is usually formed by cold rolling. Energy storage device components such as electrodes and electrolytes are arranged in the space formed by the recess. Then, the heat-welding resin layer is heat-fused, thereby obtaining an energy storage device in which energy storage device components are housed inside the outer packaging material for energy storage devices.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2008-287971 Summary of the Invention

[0011] The technical problem that the invention aims to solve

[0012] The use of rare metals and other components in energy storage devices has led to a surge in demand for these materials. Therefore, when replacing energy storage devices in electrical equipment and other products, it is necessary to remove the device from the product and recycle and reuse the various components contained within it.

[0013] In various products such as electrical equipment, the energy storage device is firmly fixed to the product's casing by double-sided tape or adhesive. Therefore, removing the energy storage device from the casing involves applying significant external force. Specifically, a metal scraper or similar tool is typically used to remove the device, applying considerable force. If this force is applied to the outer packaging material of the energy storage device, which is composed of a membrane-like laminate, the packaging material may be damaged during removal.

[0014] Under such circumstances, the main objective of the present invention is to provide an outer packaging material for a storage device that can prevent damage to the outer packaging material when the storage device, which is fixed to the housing with double-sided tape or the like, is peeled off from the housing.

[0015] Technical solutions for solving technical problems

[0016] To solve the aforementioned technical problems, the inventors of this invention conducted meticulous research. As a result, an outer packaging material for a battery storage device was discovered, which is composed of a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially from the outside. The substrate layer contains a polyamide film, and the crystallinity index of the polyamide film measured from the outside of the substrate layer using the ATR method of Fourier transform infrared spectroscopy is above a specified value. When a battery storage device fixed to the housing with double-sided tape or the like is peeled off from the housing, damage to the outer packaging material for the battery storage device can be prevented.

[0017] This invention is the result of further and repeated research based on this knowledge. Specifically, this invention provides an invention in the manner described below.

[0018] An outer packaging material for an energy storage device is composed of a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially from the outside. The substrate layer includes a polyamide film, and the crystallinity index of the polyamide film, measured from the outside of the substrate layer using the ATR method of Fourier transform infrared spectroscopy, is 1.50 or higher.

[0019] Invention Effects

[0020] This invention provides an outer packaging material for a power storage device that can prevent damage to the outer packaging material when a power storage device, which is fixed to the housing by double-sided tape, is peeled off from the housing using a metal scraper or similar tool. Furthermore, this invention also provides a method for manufacturing the outer packaging material, a power storage device using the outer packaging material, and a polyamide film suitable for use as a substrate layer of the outer packaging material. Attached Figure Description

[0021] Figure 1This is a schematic diagram illustrating an example of the cross-sectional structure of the outer packaging material for the energy storage device of the present invention.

[0022] Figure 2 This is a schematic diagram illustrating an example of the cross-sectional structure of the outer packaging material for the energy storage device of the present invention.

[0023] Figure 3 This is a schematic diagram illustrating an example of the cross-sectional structure of the outer packaging material for the energy storage device of the present invention.

[0024] Figure 4 This is a schematic diagram illustrating an example of the cross-sectional structure of the outer packaging material for the energy storage device of the present invention.

[0025] Figure 5 This is a schematic diagram illustrating the method for preparing a sample used in the stripping test of the energy storage device in the embodiment.

[0026] Figure 6 These are side views (a) and top views (b) of the sample used in the stripping test of the energy storage device in the embodiment.

[0027] Figure 7 These are side views (a) and top views (b) of a sample used in the peel test of the energy storage device in the embodiment, with double-sided tape being applied.

[0028] Figure 8 This is a schematic diagram illustrating the use of a metal scraper to peel the energy storage device from a stainless steel plate during a peeling test of the energy storage device in an embodiment. Detailed Implementation

[0029] The outer packaging material for a storage device according to the present invention is characterized in that it is composed of a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially from the outside, wherein the substrate layer comprises a polyamide film, and the crystallinity index of the polyamide film, measured from the outside of the substrate layer using the ATR method of Fourier transform infrared spectroscopy, is 1.50 or higher. The outer packaging material for a storage device according to the present invention suppresses damage to the outer packaging material when a storage device fixed to the housing with double-sided tape or the like is peeled off from the housing.

[0030] The outer packaging material for the energy storage device of the present invention will now be described in detail. In this specification, the numerical range indicated by "~" means "above" or "below". For example, the expression 2 to 15 mm means 2 mm or more and 15 mm or less.

[0031] 1. The laminated structure and physical properties of outer packaging materials for energy storage devices

[0032] The outer packaging material 10 for the energy storage device of the present invention, for example Figure 1As shown, the material is composed of a laminate consisting of a substrate layer 1, a barrier layer 3, and a heat-melting resin layer 4, arranged sequentially from the outside. In the outer packaging material 10 for a power storage device, the substrate layer 1 is the outermost layer, and the heat-melting resin layer 4 is the innermost layer. When assembling a power storage device using the outer packaging material 10 and power storage device components, the peripheral portions of the heat-melting resin layers 4 of the outer packaging material 10 are heat-melted together with the layers facing each other, thereby housing the power storage device components within the resulting space. In the laminate constituting the outer packaging material 10 for a power storage device of the present invention, with the barrier layer 3 as a reference, the side with the heat-melting resin layer 4 is the inner side compared to the barrier layer 3, and the side with the substrate layer 1 is the outer side compared to the barrier layer 3.

[0033] 10 Examples of outer packaging materials for energy storage devices Figures 2 to 4 As shown, an adhesive layer 2 may be provided between the substrate layer 1 and the barrier layer 3 to improve the adhesion between these layers, as needed. Additionally, for example... Figure 3 and Figure 4 As shown, an adhesive layer 5 may be provided between the barrier layer 3 and the thermoplastic resin layer 4 to improve the adhesion between these layers, etc., as needed. Additionally, as... Figure 5 As shown, a surface covering layer 6 may also be provided on the outside of the substrate layer 1 (on the side opposite to the thermosetting resin layer 4) as needed.

[0034] There is no particular limitation on the thickness of the laminated body constituting the outer packaging material 10 for the energy storage device. Regarding the upper limit, from the viewpoint of cost reduction and energy density improvement, it is preferable to include about 180 μm or less, about 155 μm or less, and about 120 μm or less. Regarding the lower limit, from the viewpoint of maintaining and protecting the function of the outer packaging material for the energy storage device, it is preferable to include about 35 μm or more, about 45 μm or more, and about 60 μm or more. Regarding the preferred range, for example, it is preferable to include 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, and about 60 to 120 μm. Among these, 60 to 120 μm is particularly preferred.

[0035] In the outer packaging material 10 for an energy storage device, the ratio of the total thickness of the substrate layer 1, the adhesive layer 2 (provided as needed), the barrier layer 3, the adhesive layer 5 (provided as needed), the thermosetting resin layer 4, and the surface covering layer 6 (provided as needed) to the thickness (total thickness) of the laminate constituting the outer packaging material 10 for an energy 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 outer packaging material 10 for an energy storage device of the present invention includes the substrate layer 1, the adhesive layer 2, the barrier layer 3, the adhesive layer 5, and the thermosetting resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the outer packaging material 10 for an energy storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0036] The substrate layer 1 of the outer packaging material 10 for the energy storage device of the present invention comprises a polyamide film, and the crystallinity index of the polyamide film, measured from the outside of the substrate layer 1 using the ATR method of Fourier transform infrared spectroscopy, is 1.50 or higher. The method for measuring the crystallinity index of the substrate layer 1 of the outer packaging material 10 for the energy storage device of the present invention is as follows.

[0037] <Determination of the Crystallization Index of the Substrate Layer of Outer Packaging Material for Energy Storage Devices>

[0038] The energy storage device was cut into 100mm × 100mm squares using the outer packaging material to prepare a sample. Infrared absorption spectroscopy was performed on the surface of the polyamide film on the outer side of the obtained sample using FT-IR in ATR mode at 25°C and 50% relative humidity. For example, a Nicolet iS10 device manufactured by Thermo Fisher Scientific could be used. Based on the obtained absorption spectrum, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The peak intensity Q is nearby, and the intensity ratio X = P / Q, which is the ratio of peak intensity P to peak intensity Q, is used as the crystallinity index. Specifically, when determining the crystallinity index of the substrate layer of the outer packaging material for the energy storage device, the sample is prepared from the top or bottom surface, not from the heat-sealed part or side of the energy storage device.

[0039] (Measurement conditions)

[0040] Method: macroATR method;

[0041] Wavenumber resolution: 8cm -1 ;

[0042] Total number of times: 32;

[0043] Detector: DTGS detector;

[0044] ATR prism: Ge;

[0045] Angle of incidence: 45°;

[0046] Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The distance between them is obtained by approximation using a straight line.

[0047] Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range;

[0048] Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

[0049] Furthermore, when the outer surface of the outer packaging material 10 for the energy storage device is composed of a polyamide film of the substrate layer 1, the outer packaging material 10 for the energy storage device can be directly used as the object for measuring the crystallinity index. Additionally, when the substrate layer 1 has a multilayer structure as described later, and a resin film (e.g., a polyester film) different from the polyamide film is located further out than the polyamide film, or when a surface covering layer 6 (described later) is laminated on the outer side of the substrate layer 1, or when the outer surface of the outer packaging material 10 for the energy storage device is not composed of a polyamide film of the substrate layer 1, the layer located further out than the polyamide film can be removed from the outer packaging material 10 for the energy storage device to expose the surface of the polyamide film for measuring the crystallinity index.

[0050] In the outer packaging material 10 for the energy storage device, a crystallinity index of 1.50 or higher is acceptable. From the viewpoint of more effectively suppressing damage to the outer packaging material during the aforementioned peeling process, a crystallinity index of 1.55 or higher is more preferred, 1.60 or higher is even more preferred, and 1.65 or higher is particularly preferred. Furthermore, there is no particular limitation on the upper limit of the crystallinity index; for example, values ​​of 2.50 or lower and 1.80 or lower can be listed. Preferred ranges for the crystallinity index include, for example, 1.50–2.50, 1.60–2.50, 1.65–2.50, 1.50–1.80, 1.60–1.80, and 1.65–1.80.

[0051] As a method to increase the crystallinity index of the polyamide film contained in the substrate layer 1 of the outer packaging material 10 for energy storage devices to 1.50 or more, methods that promote crystallization (promote the formation of α crystals) by utilizing the stretching ratio, heat setting temperature, and post-heating temperature and time of the polyamide film manufacturing process can be cited.

[0052] 2. Forming each layer of the outer packaging material for the energy storage device

[0053] [Substrate Layer 1]

[0054] In this invention, the substrate layer 1 is a layer provided for the purpose of functioning as a substrate for the outer packaging material of an energy storage device. The substrate layer 1 is located on the outer side of the outer packaging material for the energy storage device.

[0055] The substrate layer 1 comprises a polyamide film. As described above, the crystallinity index of the polyamide film measured from the outside of the substrate layer 1 using the ATR method of Fourier transform infrared spectroscopy is 1.50 or higher.

[0056] The polyamide used to form the polyamide film can be any polyamide with α-crystals, and examples include aliphatic polyamides such as nylon 6, nylon 66, nylon 46, and copolymers of nylon 6 and nylon 66. These polyamides can be used alone or in combination of two or more. Nylon films are preferred for polyamide films.

[0057] The polyamide film can be either an unstretched film or a stretched film. When the substrate layer 1 includes an unstretched film, the unstretched film can be formed by extrusion molding, laminating a pre-prepared unstretched film, or coating with resin (polyamide) to form the unstretched film when the storage device is laminated with the layers of the outer packaging material 10. Methods for coating the resin include roller coating, gravure coating, and extrusion coating. Alternatively, when the substrate layer 1 is a stretched film, a pre-prepared stretched film can be laminated when the storage device is laminated with the layers of the outer packaging material 10. Stretch films include uniaxial stretched films and biaxial stretched films, with biaxial stretched films being preferred. Stretching methods for forming biaxial stretched films include, for example, sequential biaxial stretching, blow molding, and simultaneous biaxial stretching.

[0058] Polyamide films are particularly preferred to be biaxially stretched nylon films.

[0059] In the outer packaging material 10 for the energy storage device of the present invention, a polyamide film with a crystallinity index of 1.50 or higher as measured by the ATR method of Fourier transform infrared spectroscopy can also be manufactured for use in the substrate layer 1. Alternatively, the crystallinity index can be increased to 1.50 or higher by applying heat to the polyamide film during the manufacturing process of the outer packaging material 10 for the energy storage device. As described in item "5. Polyamide film" below, in the outer packaging material 10 for the energy storage device of the present invention, it is preferable to manufacture a polyamide film with a crystallinity index of 1.50 or higher as measured by the ATR method of Fourier transform infrared spectroscopy for use in the substrate layer 1. That is, it is preferable to use a polyamide film with a pre-adjusted crystallinity index of 1.50 or higher in the substrate layer 1, and then laminate it with layers such as the barrier layer 3 and the heat-welding resin layer 4, thereby manufacturing the outer packaging material 10 for the energy storage device of the present invention. As shown in the embodiments described later, when the polyamide film is laminated onto the outer packaging material 10 for the energy storage device, the crystallinity index of the polyamide film contained in the substrate layer 1 can be increased compared to the polyamide film applied before the outer packaging material 10 for the energy storage device.

[0060] Regarding the thickness of the polyamide film, from the viewpoint of more effectively suppressing damage to the outer packaging material of the energy storage device during the aforementioned peeling, it is preferably about 3 μm or more, more preferably about 10 μm or more, and preferably about 50 μm or less, more preferably about 35 μm or less. As a preferred range, about 3 to 50 μm, about 3 to 35 μm, about 10 to 50 μm, and about 10 to 35 μm can be listed, among which about 10 to 35 μm is particularly preferred.

[0061] The substrate layer 1 may also have a resin film different from the polyamide film. Examples of resins that form a resin film different from the polyamide film include polyester, polyolefin, epoxy resin, acrylic resin, fluoropolymer, polyurethane, silicone resin, phenolic resin, and modified versions of these resins. Alternatively, the resin may be a copolymer of these resins or a modified version of the copolymer. It may also be a mixture of these resins. Polyester is preferred among these.

[0062] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyesters. Additionally, examples of copolyesters include copolyesters whose main body is composed of polyethylene terephthalate as a repeating unit. Specifically, examples include copolymer polyesters (hereinafter referred to as poly(terephthalic acid / isophthalic acid) glycol ester, poly(terephthalic acid / adipic acid) glycol ester, poly(terephthalic acid / sodium sulfonate) glycol ester, poly(terephthalic acid / sodium isophthalate) glycol ester, poly(terephthalic acid / phenyl-dicarboxylic acid) glycol ester, and poly(terephthalic acid / decanedicarboxylic acid) glycol ester, etc., which are polymerized with polyethylene terephthalate as the main repeating unit and then polymerized with polyethylene isophthalate. These polyesters can be used alone or in combination of two or more. Among these, polyethylene terephthalate and polybutylene terephthalate are preferred.

[0063] The polyester film is preferably a stretched polyester film, and more preferably a biaxially stretched polyester film.

[0064] The polyester film is particularly preferably a biaxially stretched polyethylene terephthalate film or a biaxially stretched polybutylene terephthalate film.

[0065] When the substrate layer 1 also has a resin film different from the polyamide film, there are no particular restrictions on the thickness of the other resin films as long as they do not impede the effect of the present invention. Preferably, it is about 3 μm or more, more preferably about 10 μm or more, and preferably about 50 μm or less, more preferably about 35 μm or less. As a preferred range, about 3 to 50 μm, about 3 to 35 μm, about 10 to 50 μm, and about 10 to 35 μm can be listed. Among these, about 10 to 35 μm is particularly preferred.

[0066] When the substrate layer 1 contains a polyamide film, it can be a single layer or composed of two or more layers. From the viewpoint of making the outer packaging material 10 for the energy storage device thinner, a single layer of polyamide film is preferred.

[0067] When the substrate layer 1 consists of two or more layers, the substrate layer 1 can be a laminate formed by laminating resin films using an adhesive or the like, or it can be a laminate formed by co-extruding resin to form two or more resin films. Furthermore, for a laminate formed by co-extruding resin to form two or more resin films, the substrate layer 1 can be formed directly without stretching, or it can be formed after uniaxial or biaxial stretching.

[0068] In the substrate layer 1, specific examples of a laminate of two or more resin films include a laminate of polyester film and nylon film, a laminate of two or more nylon films, etc., with a laminate of stretched nylon film and stretched polyester film, or a laminate of two or more stretched nylon films being more preferred. For example, when the substrate 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. In addition, regarding polyester resin, for example, considering that it is not easy to discolor when the electrolyte adheres to the surface, when the substrate layer 1 is a laminate of two or more resin films, it is preferable that the polyester resin film is located as the outermost layer of the substrate layer 1.

[0069] When the substrate layer 1 is a laminate of two or more resin films, an adhesive can be used to laminate the two or more resin films. Regarding preferred adhesives, the same adhesives exemplified in adhesive layer 2 described later can be listed. There are no particular limitations on the method for laminating the two or more resin films; known methods can be used, such as dry lamination, sandwich lamination, extrusion lamination, and hot lamination, with dry lamination being preferred. When using dry lamination, a polyurethane adhesive is preferred as the adhesive. In this case, the thickness of the adhesive is, for example, about 2 to 5 μm. Alternatively, an tackifying coating can be formed and laminated onto the resin film. The same adhesives exemplified in adhesive layer 2 described later can be used for the tackifying coating. In this case, the thickness of the tackifying coating is, for example, about 0.01 to 1.0 μm.

[0070] Additionally, additives such as lubricants, flame retardants, anti-blocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present on at least one of the surfaces and interiors of the substrate layer 1. Only one type of additive may be used, or two or more may be mixed.

[0071] In this invention, from the viewpoint of improving the formability of the outer packaging material for the energy storage device, it is preferable to have a lubricant on the surface of the substrate layer 1. There are no particular limitations on the lubricant, but amide-based lubricants are preferred. Specific examples of amide-based lubricants include saturated fatty amides, unsaturated fatty amides, substituted amides, hydroxymethylamides, saturated fatty diamides, unsaturated fatty diamides, fatty acid ester amides, and aromatic diamides. Specific examples of saturated fatty amides include laurylamide, palmitamide, stearamide, betaine, and hydroxystearamide. Specific examples of unsaturated fatty amides include oleamide and erucamide. Specific examples of substituted amides include N-oleopalmitamide, N-stearylstearamide, N-stearyloleic amide, N-oleostearamide, and N-stearylerucamide. Additionally, specific examples of hydroxymethylamides include hydroxymethylstearamide. Specific examples of saturated fatty acid diamides include methylene bis-stearamide, ethylene bis-decanoamide, ethylene bis-lauranamide, ethylene bis-stearamide, ethylene bis-hydroxystearamide, ethylene bis-betaineamide, hexamethylene bis-stearamide, hexamethylene bis-betaineamide, hexamethylene hydroxystearamide, N,N'-distearate adipamide, and N,N'-distearate sebacamide. Specific examples of unsaturated fatty acid diamides include ethylene dioleamide, ethylene dierucamide, hexamethylene dioleamide, N,N'-dioleoyl hexamamide, and N,N'-dioleoyl sebacamide. Specific examples of fatty acid ester amides include stearamide ethyl stearate. Furthermore, specific examples of aromatic diamides include isophthalimethylene bis-stearamide, isophthalimethylene bis-hydroxystearamide, and N,N'-distearate isophthalamide. One type of lubricant can be used alone, or two or more types can be used in combination.

[0072] When a lubricant is present on the surface of the substrate layer 1, there are no particular limitations on its amount, but approximately 3 mg / m³ is a preferred example. 2 Above, more preferably 4-15 mg / m² 2 Approximately 5-14 mg / m², with further optimization. 2 about.

[0073] Regarding the lubricant present on the surface of the substrate layer 1, it can be a lubricant that seeps out from the lubricant contained in the resin constituting the substrate layer 1, or it can be a lubricant coated on the surface of the substrate layer 1.

[0074] Regarding the total thickness of the substrate layer 1, there are no particular limitations as long as it can perform its function as a substrate. For example, it can be around 3 to 50 μm, preferably around 10 to 35 μm.

[0075] [coating]

[0076] To improve printability and formability, the outer packaging material for the energy storage device of the present invention may, as needed, have a coating (not shown) on the substrate layer 1 (the side of the substrate layer 1 opposite to the barrier layer 3). The coating is positioned to contact the substrate layer 1. The thickness of the coating is not particularly limited as long as it fulfills the aforementioned functions of the coating; for example, approximately 0.01 to 0.40 μm, preferably approximately 0.01 to 0.30 μm, and more preferably approximately 0.1 to 0.30 μm are examples. With a thickness of 0.01 μm or more, a layer of uniform film thickness can be formed on the substrate layer 1. As a result, the printability of the outer packaging material for the energy storage device of the present invention is uniform, allowing for uniform printing and achieving uniform formability.

[0077] Examples of resins that can form a coating include polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, polyolefins, acid-modified polyolefins, polyesters, epoxy resins, phenolic resins, fluoropolymers, cellulose esters, polyurethanes, acrylic resins, and polyamides. Among these, polyurethanes, polyesters, and acrylic resins are preferred.

[0078] To improve smoothness, the coating may contain lubricants and additives as needed. Examples of lubricants include those described above. Examples of additives include those described in the surface coating layer 6. The content and particle size of these lubricants or additives can be appropriately adjusted according to the coating thickness.

[0079] Furthermore, to improve the adhesion of the layers adjacent to the substrate layer, the outer packaging material for the energy storage device of the present invention may, as needed, have a coating on one surface (the side of the barrier layer 3 of the substrate layer 1, and the side of the substrate layer 1 opposite to the barrier layer 3) or both surfaces (illustrations omitted). That is, the coating provided on the substrate layer may be a layer provided to improve printability, moldability, etc., or a layer provided to improve the adhesion of the substrate layer. When the coating aims to improve the adhesion of the substrate layer, the resin forming the coating and its thickness may be the same as those of the coating described above. In addition, the coating may contain the aforementioned lubricant and additives. In the case where there is a layer adjacent to the coating on the side opposite to the substrate layer, it is preferable that the coating does not contain lubricant or additives.

[0080] [Adhesive layer 2]

[0081] In the outer packaging material for the energy storage device of the present invention, the adhesive layer 2 is a layer provided between the substrate layer 1 and the barrier layer 3 as needed for the purpose of improving the adhesion between them.

[0082] The adhesive layer 2 is formed of an adhesive capable of bonding the substrate layer 1 and the barrier layer 3. The adhesive used to form the adhesive layer 2 is not limited; chemically reactive, solvent-volatile, hot-melt, and hot-press adhesives are all acceptable. Furthermore, it can be a two-component curing adhesive, a one-component curing adhesive, or a resin that does not undergo a curing reaction. Additionally, the adhesive layer 2 can be a single layer or multiple layers.

[0083] Specifically, adhesive components included in adhesives can include: polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyesters; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, and nylon 12; polyolefin 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 can be used individually or in combination. Among these adhesive components, polyurethane adhesives are preferred. Furthermore, the bonding strength can be improved by combining the resins that form these adhesive components with a suitable curing agent. The curing agent is appropriately selected from polyisocyanates, polyfunctional epoxy resins, oxazoline-containing polymers, polyamine resins, acid anhydrides, etc., depending on the functional groups possessed by the adhesive components.

[0084] Examples of polyurethane adhesives include those comprising a polyol compound as the main agent and an isocyanate compound as the curing agent. Preferably, two-component curing polyurethane adhesives are those using polyester polyols, polyether polyols, and acrylic polyols as the main agent and aromatic or aliphatic polyisocyanates as the curing agent. Furthermore, polyester polyols with hydroxyl groups on the outer chains in addition to the terminal hydroxyl groups of the repeating units are preferred as the polyol compound. By forming the adhesive layer 2 with a polyurethane adhesive, excellent electrolyte resistance can be imparted to the outer packaging material of the energy storage device, and peeling of the substrate layer 1 can be suppressed even if electrolyte adheres to the sides.

[0085] Furthermore, as long as adhesion is not impaired, other components may be added to the adhesive layer 2, such as colorants, thermoplastic elastomers, tackifiers, and fillers. By including colorants in the adhesive layer 2, the outer packaging material of the energy storage device can be colored. Known colorants such as pigments and dyes can be used as colorants. Additionally, only one type of colorant may be used, or two or more may be mixed.

[0086] There are no particular limitations on the type of pigment, as long as it does not impair the adhesive properties of adhesive layer 2. Examples of organic pigments include azo, phthalocyanine, quinacridone, anthraquinone, dioxazine, indigo-thioindigo, violet-perylene, isopyridine, and benzimidazolone pigments. Examples of inorganic pigments include carbon black, titanium dioxide, cadmium, lead, chromium oxide, iron, and copper pigments. Additionally, mica powder and fish scale foil are also acceptable. Pigments can be used alone or in combination, for example, a mixture of organic and inorganic pigments.

[0087] Among colorants, carbon black is preferred, for example, to make the outer packaging material of an energy storage device appear black.

[0088] There are no particular limitations on the average particle size of the pigment; for example, it can be around 0.05 to 5 μm, preferably around 0.08 to 2 μm. The average particle size of the pigment is the median particle size measured using a laser diffraction / scattering particle size distribution measuring device.

[0089] The amount of pigment in the adhesive layer 2 is not particularly limited as long as the outer packaging material of the storage device can be colored; for example, about 5 to 60% by mass, preferably 8 to 40% by mass, can be listed.

[0090] As long as the substrate layer 1 and the barrier layer 3 can be bonded, there is no particular limitation on the thickness of the adhesive layer 2. For example, the lower limit can be 1 μm or more, or about 2 μm or more. For the upper limit, it can be 10 μm or less, or about 5 μm or less. For the preferred range, it can be 1 to 10 μm, 1 to 5 μm, 2 to 10 μm, or 2 to 5 μm.

[0091] [Shading layer]

[0092] The coloring layer is a layer that is provided as needed between the substrate layer 1 and the barrier layer 3 (illustration omitted). When an adhesive layer 2 is present, the coloring layer can be provided between the substrate layer 1 and the adhesive layer 2, and between the adhesive layer 2 and the barrier layer 3. Alternatively, the coloring layer can be provided on the outside of the substrate layer 1. By providing the coloring layer, the outer packaging material of the energy storage device can be colored.

[0093] A coloring layer can be formed, for example, by applying an ink containing a colorant to the surface of the substrate 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 as colorants. Furthermore, only one type of colorant can be used, or two or more can be mixed.

[0094] As a specific example of the colorant contained in the coloring layer, the same colorant as the colorant shown in the column of [Adhesive Layer 2] can be shown.

[0095] [Barrier Layer 3]

[0096] In the outer packaging material for energy storage devices, the barrier layer 3 is a layer that at least inhibits the infiltration of moisture.

[0097] Examples of barrier layers 3 include barrier metal foils, vapor-deposited films, and resin layers. Vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Resin layers include polyvinylidene chloride, polymers with trichlorotrifluoroethylene (CTFE) as the main component, polymers with tetrafluoroethylene (TFE) as the main component, polymers containing fluoroalkyl groups, and polymers with fluoroalkyl units as the main component, as well as ethylene-vinyl alcohol copolymers. Additionally, barrier layers 3 can also include resin films having at least one of these vapor-deposited films and resin layers. Multiple layers of barrier layer 3 can be provided. Barrier layer 3 preferably includes a layer made of a metallic material. Specific examples of metallic materials constituting barrier layer 3 include aluminum alloys, stainless steel, titanium steel, and steel plates. When a metal foil is used, at least one of aluminum alloy foil and stainless steel foil is preferred.

[0098] Regarding aluminum alloy foil, from the viewpoint of improving the formability of the outer packaging material for energy storage devices, soft aluminum alloy foil made of annealed aluminum alloys is preferred, for example; from the viewpoint of further improving formability, aluminum alloy foil containing iron 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. When the iron content is 0.1% by mass or more, an outer packaging material for energy storage devices with superior formability can be obtained. When the iron content is 9.0% by mass or less, an outer packaging material for energy storage devices with superior flexibility can be obtained. Examples of soft aluminum alloy foils include those with compositions specified in JIS H4160:1994A8021H-O, JIS H4160:1994A8079H-O, JIS H4000:2014A8021P-O, or JIS H4000:2014A8079P-O. Silicon, magnesium, copper, manganese, etc., may also be added as needed. Furthermore, softening can be achieved through annealing or similar processes.

[0099] Furthermore, examples of stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation-hardening stainless steel foils. Moreover, from the viewpoint of providing an outer packaging material for energy storage devices with excellent formability, stainless steel foil made of austenitic stainless steel is preferred.

[0100] Specific examples of stainless steels that constitute the austenitic system of stainless steel foil include SUS304, SUS301, and SUS316L, among which SUS304 is particularly preferred.

[0101] Regarding the thickness of the barrier layer 3, when it is a metal foil, it is sufficient to function as a barrier layer that at least inhibits the penetration of moisture; for example, a thickness of about 9 to 200 μm is acceptable. Regarding the thickness of the barrier layer 3, for example, regarding the upper limit, preferably about 85 μm or less, more preferably about 50 μm or less, further preferably about 40 μm or less, and particularly preferably about 35 μm or less; regarding the lower limit, preferably about 10 μm or more, further preferably about 20 μm or more, and more preferably about 25 μm or more. Preferred ranges for this thickness include approximately 10–85 μm, approximately 10–50 μm, approximately 10–40 μm, approximately 10–35 μm, approximately 20–85 μm, approximately 20–50 μm, approximately 20–40 μm, approximately 20–35 μm, approximately 25–85 μm, approximately 25–50 μm, approximately 25–40 μm, and approximately 25–35 μm, with approximately 25–40 μm being particularly preferred. When the barrier layer 3 is made of aluminum alloy foil, the above-mentioned ranges are particularly preferred. Furthermore, especially when the barrier layer 3 is made of stainless steel foil, regarding the thickness of the stainless steel foil, the upper limit can be listed as approximately 60 μm or less, more preferably approximately 50 μm or less, further preferably approximately 40 μm or less, further preferably approximately 30 μm or less, and particularly preferably approximately 25 μm or less. Regarding the lower limit, the lower limit can be listed as approximately 10 μm or more, more preferably approximately 15 μm or more. The preferred thickness range can be listed as approximately 10–60 μm, approximately 10–50 μm, approximately 10–40 μm, approximately 10–30 μm, approximately 10–25 μm, approximately 15–60 μm, approximately 15–50 μm, approximately 15–40 μm, approximately 15–30 μm, and approximately 15–25 μm.

[0102] Furthermore, when the barrier layer 3 is a metal foil, to prevent dissolution, corrosion, etc., it is preferable to have a corrosion-resistant coating on at least one surface opposite to the substrate layer. The barrier layer 3 may also have a corrosion-resistant coating on both surfaces. This corrosion-resistant coating refers to a thin film that makes the barrier layer corrosion-resistant by performing hot water modification treatments such as boehmite treatment, chemical surface treatments, anodizing, nickel or chromium plating, or anti-corrosion treatments such as applying a coating agent. One or more treatments can be performed to form the corrosion-resistant coating. Furthermore, it can be multiple layers, not just one. In these treatments, hot water modification and anodizing are processes that use a treatment agent to dissolve the surface of the metal foil to form a metal compound with excellent corrosion resistance. These treatments are sometimes also included within the definition of chemical surface treatment. Additionally, when the barrier layer 3 has a corrosion-resistant coating, the barrier layer 3 includes the corrosion-resistant coating.

[0103] The corrosion-resistant coating exhibits the following effects when molding outer packaging materials for energy storage devices: preventing delamination between the barrier layer (e.g., aluminum alloy foil) and the substrate layer; preventing the barrier layer surface from dissolving and corroding due to hydrogen fluoride generated by the reaction of electrolyte and moisture, especially when the barrier layer is aluminum alloy foil, preventing the dissolution and corrosion of alumina present on the barrier layer surface; and improving the adhesion (wetting) of the barrier layer surface; preventing delamination between the substrate layer and the barrier layer during heat sealing; and preventing delamination between the substrate layer and the barrier layer during molding.

[0104] Various corrosion-resistant coatings formed by chemical surface treatments are known, including corrosion-resistant coatings containing at least one of phosphates, chromates, fluorides, triazine thiols, and rare earth oxides. Examples of chemical surface treatments using phosphates or chromates include chromate-chromate treatment, chromate-phosphate 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 dihydrogen phosphate, acetoacetate chromate, chromium chloride, and potassium chromium sulfate. Examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphates. Examples of chromate treatments include etched chromate treatment, electrolytic chromate treatment, and coating-type chromate treatment, with coating-type chromate treatment being preferred. The coating-type chromate treatment is performed as follows: First, the surface of at least the inner layer of the barrier layer (e.g., aluminum alloy foil) is degreased using known treatment methods such as alkaline immersion, electrolytic cleaning, acid cleaning, electrolytic acid cleaning, and acid activation. Then, a treatment solution mainly composed of metal phosphate salts such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, and Zn (zinc) phosphate, or a mixture thereof, or mainly composed of non-metallic phosphate salts and a mixture thereof, or a mixture thereof with synthetic resins, is applied to the degreased surface using known coating methods such as roller coating, gravure printing, and immersion. The surface is then dried. Various solvents can be used as the treatment solution, such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, and ether-based solvents; water is preferred. Furthermore, as resin components used at this time, examples include phenolic resins, acrylic resins, and other polymers, and examples include chromate treatment of aminophenolic polymers having repeating units shown in the following general formulas (1) to (4). In addition, in this aminophenolic polymer, the repeating units shown in the following general formulas (1) to (4) may contain only one type, or may be any combination of two or more types. The acrylic resin is preferably polyacrylic acid, methacrylate copolymer of acrylate, maleic acid copolymer of acrylate, styrene copolymer of acrylate, or derivatives thereof such as sodium salts, ammonium salts, or amine salts. Derivatives of polyacrylic acid such as ammonium salts, sodium salts, or amine salts of polyacrylic acid are particularly preferred. In this invention, polyacrylic acid refers to a polymer of acrylic acid. Furthermore, the acrylic resin is also preferably a copolymer of acrylic acid with dicarboxylic acid or dicarboxylic anhydride, and even more preferably an ammonium salt, sodium salt, or amine salt of a copolymer of acrylic acid with dicarboxylic acid or dicarboxylic anhydride.

[0105] Acrylic resins can be used in combination with one type or two or more types.

[0106]

[0107]

[0108] In general formulas (1) to (4), X represents a hydrogen atom, hydroxyl group, alkyl group, hydroxyalkyl group, allyl group, or benzyl group. Additionally, R... 1 and R 2 The same or different respectively indicate hydroxyl, alkyl, or hydroxyalkyl. In general formulas (1) to (4), X and R are used respectively. 1 and R 2 The alkyl groups shown can include, for example, straight-chain or branched alkyl groups with 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. Additionally, as X and R... 1 and R 2 The hydroxyalkyl groups shown can be, for example, hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 3-hydroxypropyl, 1-hydroxybutyl, 2-hydroxybutyl, 3-hydroxybutyl, 4-hydroxybutyl, etc., which are straight-chain or branched alkyl groups with 1 to 4 carbon atoms that have substituted one hydroxyl group. In general formulas (1) to (4), X, R 1 and R 2 The alkyl and hydroxyalkyl groups shown may be the same or different. In general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxyl group, or a hydroxyalkyl group. The number-average molecular weight of the aminophenolic polymer having the repeating units shown in general formulas (1) to (4) is preferably about 5 million to 1 million, more preferably about 10 million to 20,000. The aminophenolic polymer can be manufactured, for example, by polycondensing a phenolic compound or a naphthol compound with formaldehyde to produce a polymer containing the repeating units shown in general formula (1) or general formula (3) above, and then using formaldehyde and an amine (R 1 R 2 NH) will have a functional group (-CH2NR) 1 R 2 The above-obtained polymer is introduced into the polymer to produce an aminophenolic polymer. An aminophenolic polymer can be used alone or in combination of two or more.

[0109] Other examples of corrosion-resistant coatings include films formed by coating-type anti-corrosion treatments using a coating agent containing at least one of rare earth element oxide sols, anionic polymers, and cationic polymers. The coating agent may also contain phosphoric acid or phosphates, or a crosslinking agent that crosslinks the polymer. Rare earth element oxide sols are obtained by dispersing particles of rare earth element oxides (e.g., particles with an average particle size of less than 100 nm) in a liquid dispersion medium. Examples of rare earth element oxides include cerium oxide, yttrium oxide, neodymium oxide, and lanthanum oxide; cerium oxide is preferred from the viewpoint of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant coating may be used alone or in combination of two or more. Various solvents can be used as the liquid dispersion medium for the rare earth element oxide sol, such as water, alcohol solvents, hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents; water is preferred. As cationic polymers, preferred examples include polyethyleneimine, ionic polymeric complexes formed from polyethyleneimine and polymers containing carboxylic acids, primary amine-grafted acrylic resins formed by grafting a primary amine to an acrylic acid backbone, polyallylamine or its derivatives, and aminophenol. As anionic polymers, preferred examples include poly(meth)acrylic acid or its salts, or copolymers with (meth)acrylic acid or its salts as the main component. Furthermore, the crosslinking agent is preferably at least one selected from compounds having any of the functional groups of isocyanate groups, glycidyl groups, carboxyl groups, and oxazoline groups, and silane coupling agents. Additionally, the aforementioned phosphoric acid or phosphate is preferably condensed phosphoric acid or condensed phosphate.

[0110] As an example of a corrosion-resistant coating, one can cite the following: dispersing metal oxides such as alumina, titanium oxide, cerium oxide, tin oxide, or barium sulfate particles in phosphoric acid, coating the resulting dispersion onto the surface of a barrier layer, and then performing a sintering treatment at a temperature above 150°C to form a coating.

[0111] Depending on the requirements, the corrosion-resistant coating can also be formed into a laminated structure containing at least one of cationic and anionic polymers. Examples of cationic and anionic polymers include those mentioned above.

[0112] The compositional analysis of corrosion-resistant coatings can be performed, for example, using time-of-flight secondary ion mass spectrometry.

[0113] There is no particular limitation on the amount of corrosion-resistant coating formed on the surface of barrier layer 3 during chemical surface treatment. For example, in the case of coating-type chromate treatment, it is desirable that the coating be applied to every 1m of barrier layer 3. 2On the surface, the content of chromic acid compound, calculated in terms of chromium, is for example about 0.5 to 50 mg, preferably about 1.0 to 40 mg; the content of phosphorus compound, calculated in terms of phosphorus, is for example about 0.5 to 50 mg, preferably about 1.0 to 40 mg; and the content of aminophenolic polymer is for example about 1.0 to 200 mg, preferably about 5.0 to 150 mg.

[0114] There are no particular limitations on the thickness of the corrosion-resistant coating. From the viewpoint of the coating's cohesiveness and adhesion to the barrier layer or the thermosetting resin layer, a thickness of approximately 1 nm to 20 μm is preferred, more preferably approximately 1 nm to 100 nm, and even more preferably approximately 1 nm to 50 nm. The thickness of the corrosion-resistant coating can be determined by observation using a transmission electron microscope (TEM), or by a combination of TEM and energy-dispersive X-ray spectroscopy or electron beam energy loss spectroscopy. Compositional analysis of the corrosion-resistant coating using time-of-flight secondary ion mass spectrometry (TOF-MS) can detect secondary ions (e.g., Ce₂PO₄) composed of Ce, P, and O. + CePO4 - (at least one of the following), for example, secondary ions composed of Cr, P and O (e.g., CrPO2). + CrPO4 - (at least one of the peaks)

[0115] Regarding chemical surface treatment, the following methods are used: A solution containing a compound used to form a corrosion-resistant coating is applied to the surface of the barrier layer using methods such as bar coating, roller coating, gravure coating, or immersion coating. The barrier layer is then heated to approximately 70–200°C to perform the chemical surface treatment. Alternatively, before performing the chemical surface treatment on the barrier layer, it can be pre-treated by degreasing using methods such as alkaline immersion, electrolytic cleaning, acid cleaning, or electrolytic acid cleaning. This degreasing treatment allows for more effective chemical surface treatment of the barrier layer. Furthermore, by using an acid degreasing agent obtained by dissolving fluorine-containing compounds in an inorganic acid during the degreasing process, not only is the metal foil degreased, but a passivated metal fluoride can also be formed. In this case, degreasing alone may be sufficient.

[0116] [Thermo-Melt Resin Layer 4]

[0117] In the outer packaging material for the energy storage device of the present invention, the heat-fusion resin layer 4 is equivalent to the innermost layer, which is a layer (sealing layer) that performs the function of heat-fusion resin layers to heat-fusel each other and seal the energy storage device components during the assembly of the energy storage device.

[0118] The resin constituting the heat-melting resin layer 4 is not particularly limited as long as it can be heat-melted; resins containing a polyolefin backbone, such as polyolefins and acid-modified polyolefins, are preferred. The resin constituting the heat-melting resin layer 4 contains a polyolefin backbone, and analysis can be performed, for example, using infrared spectroscopy or gas chromatography-mass spectrometry. Furthermore, when analyzing the resin constituting the heat-melting resin layer 4 using infrared spectroscopy, it is preferable to detect a peak from maleic anhydride. For example, when measuring maleic anhydride-modified polyolefins using infrared spectroscopy, a peak at a wavenumber of 1760 cm⁻¹ is preferred. -1 Nearby and wave number 1780cm -1 A peak from maleic anhydride was detected nearby. When the heat-fused resin layer 4 is composed of a maleic anhydride-modified polyolefin, a peak from maleic anhydride was detected during infrared spectroscopy. However, when the degree of acid modification is low, the peak may sometimes become too small to detect. In such cases, nuclear magnetic resonance spectroscopy can be used for analysis.

[0119] Specifically, examples of polyolefins include: low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and other polyethylenes; ethylene-α-olefin copolymers; homopolymer polypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene), etc.; propylene-α-olefin copolymers; ethylene-butene-propylene terpolymers, etc. Among these, polypropylene is preferred. When it is a copolymer, the polyolefin resin can be a block copolymer or a random copolymer. These polyolefin resins can be used alone or in combination of two or more.

[0120] Alternatively, the polyolefin can also be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers. Examples of olefins that are constituent monomers of the aforementioned cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Examples of cyclic monomers that are constituent monomers of cyclic polyolefins include cyclic olefins such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornene. Among these, cyclic olefins are preferred, and norbornene is even more preferred.

[0121] Acid-modified polyolefins are polymers obtained by modifying polyolefins through block polymerization or graft polymerization using an acid component. The polyolefins to be acid-modified can include the aforementioned polyolefins, copolymers formed by copolymerizing polar molecules such as acrylic acid or methacrylic acid with the aforementioned polyolefins, or cross-linked polyolefins. Furthermore, examples of acid components used for acid modification include carboxylic acids or their anhydrides such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0122] Acid-modified polyolefins can be acid-modified cyclic polyolefins. Acid-modified cyclic polyolefins are polymers obtained by copolymerizing a portion of the monomers constituting the cyclic polyolefin with an acid component, or by block polymerization or graft polymerization of the acid component with the cyclic polyolefin. The same applies to acid-modified cyclic polyolefins. Furthermore, the acid component used for acid modification is the same as that used for modifying the polyolefins described above.

[0123] Preferred acid-modified polyolefins include polyolefins modified with carboxylic acids or their anhydrides, polypropylene modified with carboxylic acids or their anhydrides, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylene.

[0124] The heat-melting resin layer 4 can be formed from a single resin or from a blended polymer composed of two or more resins. Furthermore, the heat-melting resin layer 4 can be formed as a single layer or as two or more layers using the same or different resins.

[0125] Additionally, the heat-melting resin layer 4 may contain a lubricant, as needed. When the heat-melting resin layer 4 contains a lubricant, the moldability of the outer packaging material for the energy storage device can be improved. There are no particular restrictions on the lubricant used; any known lubricant can be used. One type of lubricant can be used alone, or two or more can be used in combination.

[0126] There are no particular limitations on the lubricant used, but amide-based lubricants are preferred. Specific examples of lubricants include those illustrated in substrate layer 1. A single lubricant can be used alone, or two or more can be used in combination.

[0127] When a lubricant is present on the surface of the heat-melting resin layer 4, there is no particular limitation on its amount. From the viewpoint of improving the formability of the outer packaging material for the energy storage device, an amount of 10 to 50 mg / m³ is preferred. 2 Approximately 15–40 mg / m², with further optimization preferred. 2 about.

[0128] Regarding the lubricant present on the surface of the heat-fusion resin layer 4, it can be a lubricant that seeps out from the lubricant contained in the resin constituting the heat-fusion resin layer 4, or it can be a lubricant coated on the surface of the heat-fusion resin layer 4.

[0129] Furthermore, the thickness of the heat-fusion resin layer 4 is not particularly limited as long as it enables the heat-fusion resin layers to fuse together and seal the components of the energy storage device. Examples include approximately 100 μm or less, preferably approximately 85 μm or less, and more preferably approximately 15 to 85 μm. Additionally, if the thickness of the adhesive layer 5 (described later) is 10 μm or more, the thickness of the heat-fusion resin layer 4 is preferably approximately 85 μm or less, and more preferably approximately 15 to 45 μm. If the thickness of the adhesive layer 5 (described later) is less than 10 μm or if the adhesive layer 5 is not provided, the thickness of the heat-fusion resin layer 4 is preferably approximately 20 μm or more, and more preferably approximately 35 to 85 μm.

[0130] [Adhesive Layer 5]

[0131] In the outer packaging material for the energy storage device of the present invention, the adhesive layer 5 is a layer provided between the barrier layer 3 (or corrosion-resistant coating) and the heat-melting resin layer 4 as needed to firmly bond them together.

[0132] The adhesive layer 5 is formed of a resin capable of bonding the barrier layer 3 to the heat-melting resin layer 4. As the resin used to form the adhesive layer 5, for example, the same adhesive as exemplified in the adhesive layer 2 can be used. Furthermore, the resin used to form the adhesive layer 5 preferably contains a polyolefin backbone, such as the polyolefins and acid-modified polyolefins exemplified in the aforementioned heat-melting resin layer 4. The resin constituting the adhesive layer 5 contains a polyolefin backbone, and analysis can be performed, for example, using infrared spectroscopy, gas chromatography-mass spectrometry, etc., and the analytical method is not particularly limited. Furthermore, when analyzing the resin constituting the adhesive layer 5 using infrared spectroscopy, it is preferable to detect a peak from maleic anhydride. For example, when measuring maleic anhydride-modified polyolefins using infrared spectroscopy, a peak at a wavenumber of 1760 cm⁻¹ is preferred. -1 Nearby and wave number 1780cm -1 A peak from maleic anhydride was detected nearby. However, when the acid modification degree is low, the peak may sometimes become too small to be detected. In such cases, nuclear magnetic resonance spectroscopy can be used for analysis.

[0133] From the viewpoint of firmly bonding the barrier layer 3 to the heat-melting resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. As an acid-modified polyolefin, polyolefins modified with carboxylic acids or their anhydrides, polypropylene modified with carboxylic acids or their anhydrides, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylene are particularly preferred.

[0134] Furthermore, from the viewpoint of reducing the thickness of the outer packaging material for the energy storage device and achieving 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. The above-described compound is preferably an example of the acid-modified polyolefin.

[0135] Furthermore, the adhesive layer 5 is preferably a cured product containing an acid-modified polyolefin and a resin composition selected from at least one of compounds having isocyanate groups, compounds having oxazoline groups, and compounds having epoxy groups. It is particularly preferred to be a cured product containing an acid-modified polyolefin and a resin composition selected from at least one of compounds having isocyanate groups and compounds having epoxy groups. Additionally, the adhesive layer 5 preferably contains at least one of polyurethane, polyester, and epoxy resin, more preferably polyurethane and epoxy resin. As a polyester, for example, an amide ester resin is preferred. Amide ester resins are generally generated by the reaction of carboxyl groups with oxazoline groups. The adhesive layer 5 is more preferably a cured product containing at least one of these resins and the aforementioned acid-modified polyolefin resin composition. In the event that unreacted substances of curing agents such as compounds having isocyanate groups, compounds having oxazoline groups, and epoxy resin remain in the adhesive layer 5, the presence of unreacted substances can be confirmed, for example, by methods selected from infrared spectroscopy, Raman spectroscopy, and time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0136] Furthermore, from the viewpoint of further improving the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is preferably a cured product containing a resin composition having at least one curing agent selected from oxygen atoms, heterocyclic rings, C=N bonds, and C-O-C bonds. Examples of curing agents having heterocyclic rings include curing agents having oxazoline groups and curing agents having epoxy groups. Examples of curing agents having C=N bonds include curing agents having oxazoline groups and curing agents having isocyanate groups. Examples of curing agents having C-O-C bonds include curing agents having oxazoline groups, curing agents having epoxy groups, and polyurethane. The adhesive layer 5 being a cured product of a resin composition containing these curing agents can be confirmed, for example, by methods such as gas chromatography-mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS).

[0137] There are no particular limitations on the compounds containing isocyanate groups, but from the viewpoint of effectively improving the adhesion between the barrier layer 3 and the adhesive layer 5, polyfunctional isocyanate compounds are preferred. There are no particular limitations on polyfunctional isocyanate compounds as long as they have two or more isocyanate groups. Specific examples of polyfunctional isocyanate-based curing agents include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), compounds formed by polymerizing or ureating them, mixtures thereof, or copolymers with other polymers. Additionally, adducts, biuret bodies, and isocyanurates can also be included.

[0138] The content of the isocyanate-containing compound in the adhesive layer 5 is preferably in the range of 0.1% to 50% by mass, and more preferably in the range of 0.5% to 40% by mass, in the resin composition constituting the adhesive layer 5. This effectively improves the adhesion between the barrier layer 3 and the adhesive layer 5.

[0139] There are no particular limitations on compounds containing an oxazoline group, as long as they have an oxazoline backbone. Specific examples of compounds containing an oxazoline group include compounds with a polystyrene backbone and compounds with an acrylic acid backbone. Additionally, commercially available products include, for example, the Epocros series manufactured by Nippon Shokubaisha.

[0140] The proportion of the oxazoline-containing compound in the adhesive layer 5 is preferably in the range of 0.1% to 50% by mass, and more preferably in the range of 0.5% to 40% by mass, in the resin composition constituting the adhesive layer 5. This effectively improves the adhesion between the barrier layer 3 and the adhesive layer 5.

[0141] Examples of epoxy resins can be listed as compounds containing epoxy groups. There are no particular limitations on the epoxy resin, as long as it is a resin capable of forming a cross-linked structure using the epoxy groups present within the molecule; known epoxy resins can be used. The weight-average molecular weight of the epoxy resin is preferably around 50 to 2000, more preferably around 100 to 1000, and even more preferably around 200 to 800. In the first invention, the weight-average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard sample.

[0142] Specific examples of epoxy resins include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, phenolic varnish glycidyl ether, glycerol polyglycidyl ether, and polyglycerol polyglycidyl ether. Epoxy resins can be used alone or in combination of two or more.

[0143] The proportion of epoxy resin in the adhesive layer 5 is preferably in the range of 0.1% to 50% by mass, and more preferably in the range of 0.5% to 40% by mass, in the resin composition constituting the adhesive layer 5. This effectively improves the adhesion between the barrier layer 3 and the adhesive layer 5.

[0144] There are no particular restrictions on the type of polyurethane used; any known polyurethane can be used. For example, the adhesive layer 5 can be a cured product of a two-component curing polyurethane.

[0145] The proportion of polyurethane in the adhesive layer 5 is preferably in the range of 0.1% to 50% by mass, and more preferably in the range of 0.5% to 40% by mass, in the resin composition constituting the adhesive layer 5. This effectively improves the adhesion between the barrier layer 3 and the adhesive layer 5 in an atmosphere containing components that induce corrosion of the barrier layer, such as electrolytes.

[0146] In addition, when the adhesive layer 5 is a cured product containing at least one of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin and the above-mentioned 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 function as curing agents, respectively.

[0147] Regarding the thickness of the adhesive layer 5, the upper limit is preferably 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, and about 5 μm or less; the lower limit is preferably about 0.1 μm or more and about 0.5 μm or more. The range of this thickness is preferably about 0.1–50 μm, about 0.1–40 μm, about 0.1–30 μm, about 0.1–20 μm, about 0.1–5 μm, about 0.5–50 μm, about 0.5–40 μm, about 0.5–30 μm, about 0.5–20 μm, and about 0.5–5 μm. More specifically, in the case of a cured product of the adhesive, acid-modified polyolefin, and hardener exemplified in the adhesive layer 2, a thickness of about 1–10 μm is preferred, and more preferably about 1–5 μm. Furthermore, if the resin exemplified in the heat-melting resin layer 4 is used, a thickness of approximately 2 to 50 μm is preferred, and approximately 10 to 40 μm is more preferred. When the adhesive layer 5 is a cured product of a resin composition containing an adhesive exemplified in the adhesive layer 2, an acid-modified polyolefin, and a hardener, the adhesive layer 5 can be formed, for example, by coating the resin composition and curing it using heat. Alternatively, when the resin exemplified in the heat-melting resin layer 4 is used, it can be formed, for example, by extrusion molding of the heat-melting resin layer 4 and the adhesive layer 5.

[0148] [Surface Coating 6]

[0149] To improve at least one of the following: appearance design, electrolyte resistance, scratch resistance, and formability, the outer packaging material for the energy storage device of the present invention may, as needed, have a surface covering layer 6 on the substrate layer 1 (the side of the substrate layer 1 opposite to the barrier layer 3). The surface covering layer 6 is the layer located on the outermost side of the outer packaging material for the energy storage device when assembling the energy storage device using the outer packaging material for the energy storage device.

[0150] The surface coating layer 6 can be formed from resins such as polyvinylidene chloride, polyester, polyurethane, acrylic resin, and epoxy resin.

[0151] When the resin forming the surface coating layer 6 is a curable resin, it can be either a single-component curing type or a two-component curing type, preferably a two-component curing type. Examples of two-component curing resins include two-component curing polyurethane, two-component curing polyester, and two-component curing epoxy resin. Among these, two-component curing polyurethane is preferred.

[0152] Examples of two-component curing polyurethanes include polyurethanes containing a polyol compound as the main agent and an isocyanate compound as the curing agent. Preferably, two-component curing polyurethanes use polyols such as polyester polyols, polyether polyols, and acrylic polyols as the main agent and aromatic or aliphatic polyisocyanates as the curing agent. Furthermore, polyester polyols with hydroxyl groups on the outer chains in addition to the terminal hydroxyl groups of the repeating units are preferred as the polyol compound. By forming the surface coating layer 6 from polyurethane, excellent electrolyte resistance can be imparted to the outer packaging material of the energy storage device.

[0153] Regarding the surface coating layer 6, depending on the functionality that the surface coating layer 6 or its surface should possess, at least one of the aforementioned additives such as lubricants, anti-blocking agents, matting agents, flame retardants, antioxidants, tackifiers, and antistatic agents may be contained on the surface and interior of the surface coating layer 6 as needed. Examples of additives include particles with an average particle size of approximately 0.5 nm to 5 μm. The average particle size of the additive is the median particle size measured using a laser diffraction / scattering particle size distribution measuring device.

[0154] Additives can be any type of inorganic or organic matter. Furthermore, there are no particular restrictions on the shape of the additives; for example, spherical, fibrous, plate-like, amorphous, and scaly shapes are acceptable.

[0155] 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 resins, cross-linked acrylic acid, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, etc. Additives can be used alone or in combination of two or more. From the perspective of dispersion stability and cost, silica, barium sulfate, and titanium oxide are preferred among these additives. Furthermore, various surface treatments, such as insulating treatment and high dispersibility treatment, can be applied to the surface of the additives.

[0156] There are no particular limitations on the method for forming the surface coating layer 6; for example, a method of coating the resin that forms the surface coating layer 6 can be listed. If an additive is incorporated into the surface coating layer 6, the resin mixed with the additive can be applied.

[0157] The thickness of the surface covering layer 6 is not particularly limited as long as it can perform the functions described above. For example, a thickness of about 0.5 to 10 μm, preferably about 1 to 5 μm, can be used.

[0158] 3. Manufacturing method of outer packaging material for energy storage devices

[0159] The manufacturing method of the outer packaging material for a storage device is not particularly limited as long as a laminate containing the layers of the outer packaging material for a storage device of the present invention can be obtained. Examples include methods that sequentially laminate at least a substrate layer 1, a barrier layer 3, and a heat-melting resin layer 4 from the outside. Specifically, the manufacturing method of the outer packaging material for a storage device of the present invention includes the step of obtaining a laminate containing at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially laminated from the outside. The substrate layer comprises a polyamide film, and the crystallinity index of the polyamide film, measured from the outside of the substrate layer using the ATR method of Fourier transform infrared spectroscopy, is 1.50 or higher.

[0160] As an example of a method for manufacturing the outer packaging material for the energy storage device of the present invention, it is described below. First, a laminate (hereinafter sometimes referred to as "laminate A") is formed by sequentially stacking a substrate layer 1, an adhesive layer 2, and a barrier layer 3. The laminate A is specifically formed by a dry lamination method as follows: an adhesive for forming the adhesive layer 2 is applied to the substrate layer 1 or the barrier layer 3, whose surface has been chemically surface-treated as needed, using a coating method such as gravure coating or roller coating, and then dried. The barrier layer 3 or the substrate layer 1 is then laminated, and the adhesive layer 2 is cured.

[0161] Next, a heat-melting resin layer 4 is laminated onto the barrier layer 3 of the laminate A. When the heat-melting resin layer 4 is directly laminated onto the barrier layer 3, it is sufficient to laminate the heat-melting resin layer 4 onto the barrier layer 3 of the laminate A using methods such as hot lamination or extrusion lamination. Alternatively, when an adhesive layer 5 is provided between the barrier layer 3 and the heat-melting resin layer 4, the following methods can be used: (1) a method of laminating the adhesive layer 5 and the heat-melting 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 containing the adhesive layer 5 and the heat-melting resin layer 4, and then laminating it onto the barrier layer 3 of the laminate A using a hot lamination method; or a method of forming a laminate containing the adhesive layer 5 laminated onto the barrier layer 3 of the laminate A, and then laminating it onto the barrier layer 3 of the laminate A using a hot lamination method. (2) A method of laminating the heat-melting resin layer 4 with the heat-melting resin layer 4 by pressing; (3) A method of bonding the laminated body A with the heat-melting resin layer 4 by using the adhesive layer 5 while the molten adhesive layer 5 flows between the barrier layer 3 of the laminated body A and the heat-melting resin layer 4 which is pre-formed into a sheet (laminated lamination); (4) A method of laminating an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminated body A by using a solution coating and drying method or a further sintering method, and then laminating the heat-melting resin layer 4 which is pre-formed into a sheet on the adhesive layer 5.

[0162] When the surface cover layer 6 is provided, the surface cover layer 6 is laminated on the surface of the substrate layer 1 opposite to the barrier layer 3. The surface cover layer 6 can be formed, for example, by applying the resin used to form the surface cover layer 6 to the surface of the substrate layer 1. There is no particular limitation on the order of the steps of laminating the barrier layer 3 on the surface of the substrate layer 1 and laminating the surface cover layer 6 on the surface of the substrate layer 1. For example, the barrier layer 3 can be formed on the surface of the substrate layer 1 opposite to the surface cover layer 6 after the surface cover layer 6 is formed on the surface of the substrate layer 1.

[0163] As described above, a laminated body can be formed having, from the outside, a surface cover layer 6, a substrate layer 1, an adhesive layer 2, a barrier layer 3, an adhesive layer 5, and a thermoplastic resin layer 4, provided as needed. In order to make the adhesion of the adhesive layer 2 and the adhesive layer 5 provided as needed stronger, it can also be subjected to heat treatment.

[0164] In the outer packaging materials for energy storage devices, surface activation treatments such as corona treatment, sandblasting treatment, oxidation treatment, and ozone treatment are applied to each layer constituting the laminate as needed, thereby improving processing adaptability. For example, by applying corona treatment to the surface of the substrate layer 1 opposite to the barrier layer 3, the printability of inks on the surface of the substrate layer 1 can be improved.

[0165] 4. Uses of outer packaging materials for energy storage devices

[0166] The outer packaging material for energy storage devices of the present invention can be used in packaging for sealing and housing energy storage device components such as positive electrode, negative electrode, and electrolyte. That is, it is possible to house energy storage device components having at least a positive electrode, a negative electrode, and an electrolyte in a packaging formed by the outer packaging material for energy storage devices of the present invention, thereby forming an energy storage device.

[0167] Specifically, using the outer packaging material for a storage device according to the present invention, with the metal terminals respectively connected to the positive and negative electrodes protruding outwards, a storage device element having at least a positive electrode, a negative electrode, and an electrolyte is covered in such a way that a flange portion (the area where the heat-melting resin layers contact each other) is formed at the periphery of the storage device element. The heat-melting resin layers of the flange portion are then heat-sealed to each other, thereby providing a storage device using the outer packaging material for a storage device. When the storage device element is housed in a package formed from the outer packaging material of the present invention, the heat-melting resin portion of the outer packaging material becomes the inner side (the surface in contact with the storage device element), forming the package.

[0168] The outer packaging material for energy storage devices of the present invention is applicable to energy storage devices such as batteries (including capacitors, condensers, and capacitors). Furthermore, the outer packaging material for energy storage devices of the present invention can be used in both primary and secondary batteries, with secondary batteries being preferred. There are no particular limitations on the types of secondary batteries to which the outer packaging material for energy storage devices of the present invention is applicable; 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, multivalent cation batteries, capacitors, and capacitors. Among these secondary batteries, lithium-ion batteries and lithium-ion polymer batteries are preferred applications of the outer packaging material for energy storage devices of the present invention.

[0169] Energy storage devices are typically fixed to the casing of various products using double-sided tape or adhesive. Specifically, the energy storage device of this invention is fixed to the casing of various products using the outer packaging material 10 via double-sided tape or adhesive. The casing material varies widely depending on the type of product, including, for example, metals such as stainless steel, aluminum alloy, and nickel alloy, plastics such as polyolefins, polyamides, polyesters, polyimides, and polystyrene, and glass.

[0170] Furthermore, regarding the adhesive strength between the energy storage device and the casing, it should be adjusted to a degree that allows the energy storage device to be peeled off from the casing. Regarding the peel strength between the energy storage device and the casing, it is preferable to use double-sided tape with a peel strength relative to the stainless steel plate of approximately 5-15 N / 7.5 mm, as measured later in the (determination of peel strength of double-sided tape). For energy storage devices fixed to the casing with double-sided tape having a peel strength relative to the casing of approximately 5-15 N / 7.5 mm, the outer packaging material 10 for the energy storage device can be appropriately used.

[0171] 5. Polyamide film

[0172] The polyamide film of the present invention is a polyamide film used as the substrate layer of an outer packaging material for an energy storage device, which is a laminate consisting of at least a substrate layer, a barrier layer, and a heat-melting resin layer, and has a crystallinity index of 1.50 or higher as measured by the ATR method of Fourier transform infrared spectroscopy. Details regarding the outer packaging material 10 for energy storage devices are as described above.

[0173] By using the polyamide film of the present invention as the substrate layer 1 of the outer packaging material for a battery storage device, the crystallinity index of the polyamide film in the substrate layer 1 of the outer packaging material 10 for a battery storage device can be appropriately set to 1.50 or higher, effectively suppressing damage to the outer packaging material during the aforementioned peeling process. Specifically, it is preferable to use the polyamide film of the present invention, with its crystallinity index pre-adjusted to 1.50 or higher, as the substrate layer 1, and then laminate it with layers such as the barrier layer 3 and the heat-welding resin layer 4 to manufacture the outer packaging material 10 for a battery storage device of the present invention. As described above, compared to the polyamide film applied before the outer packaging material 10 for a battery storage device, the crystallinity index of the polyamide film contained in the substrate layer 1 can be increased after lamination onto the outer packaging material 10. Specifically, the crystallinity index can also be increased by applying heat to the polyamide film during the manufacturing process of the outer packaging material 10 for a battery storage device.

[0174] Regarding the polyamide film of the present invention, the method for determining the crystallinity index is as follows.

[0175] <Determination of the Crystallization Index of Polyamide Films>

[0176] The polyamide film was cut into 100mm × 100mm squares to prepare samples. Infrared absorption spectroscopy was performed on the surface of the obtained samples using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. For example, a Nicoleti S10 manufactured by Thermo Fisher Scientific could be used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1The nearby peak intensity P and the absorption at 1370 cm⁻¹ from a crystallization-independent point. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallization index.

[0177] (Measurement conditions)

[0178] Method: macroATR method;

[0179] Wavenumber resolution: 8cm -1 ;

[0180] Total number of times: 32;

[0181] Detector: DTGS detector;

[0182] ATR prism: Ge;

[0183] Angle of incidence: 45°;

[0184] Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The distance between them is obtained by approximation using a straight line.

[0185] Absorption peak intensity Y 1200 Wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range;

[0186] Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

[0187] In the polyamide film of the present invention, a crystallinity index of 1.50 or higher is acceptable. From the viewpoint of more effectively suppressing damage to the outer packaging material of the energy storage device during the aforementioned peeling process, a crystallinity index of 1.55 or higher is more preferred, 1.60 or higher is even more preferred, and 1.65 or higher is particularly preferred. Furthermore, there is no particular limitation on the upper limit of the crystallinity index; for example, values ​​of 2.50 or lower and 1.80 or lower are possible. Preferred ranges for the crystallinity index include, for example, 1.50–2.50, 1.60–2.50, 1.65–2.50, 1.50–1.80, 1.60–1.80, and 1.65–1.80.

[0188] Specific examples of polyamide used to form polyamide films include those described in the section on substrate layer 1 of outer packaging material 10 for energy storage devices. The polyamide film can be either an unstretched film or a stretched film. Examples of stretched films include uniaxial stretched films and biaxial stretched films, with biaxial stretched films being preferred. Examples of stretching methods for forming biaxial stretched films include successive biaxial stretching, blow molding, and simultaneous biaxial stretching. Examples of resin coating methods include roller coating, gravure coating, and extrusion coating.

[0189] Polyamide films are particularly preferred to be biaxially stretched nylon films.

[0190] Regarding the thickness of the polyamide film, from the viewpoint of more effectively suppressing damage to the outer packaging material of the energy storage device during the aforementioned peeling, it is preferably about 3 μm or more, more preferably about 10 μm or more, and preferably about 50 μm or less, more preferably about 35 μm or less. As a preferred range, about 3 to 50 μm, about 3 to 35 μm, about 10 to 50 μm, and about 10 to 35 μm can be listed, among which about 10 to 35 μm is particularly preferred.

[0191] At least one of the additives, such as lubricants, flame retardants, anti-blocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents, may be present on the surface and inside the polyamide film. Only one additive may be used, or two or more may be used in combination. Details regarding the additives are described in the section on the substrate layer 1 of the outer packaging material 10 for energy storage devices.

[0192] Example

[0193] The present invention will now be described in detail with reference to exemplary embodiments and comparative examples. However, the present invention is not limited to these embodiments.

[0194] <Manufacturing of outer packaging materials for energy storage devices>

[0195] Examples 1-3 and Comparative Examples 1-2

[0196] As the substrate layer, stretched nylon (ONy) films (25 μm thick) were prepared. As described later, for the stretched nylon films used in Examples 1-3 and Comparative Examples 1-2, the stretching ratio and heat setting temperature were changed to adjust the crystallinity index to the values ​​recorded in Table 1. Erucamide was coated onto the stretched nylon film as a lubricant. As the barrier layer, an aluminum alloy foil (JIS H4160:1994A8021H-O (40 μm thick)) was prepared. Next, an adhesive (two-component polyurethane adhesive) was coated onto one surface of the aluminum alloy foil and allowed to dry. Then, the adhesive on the barrier layer was laminated to the substrate layer using a dry lamination method, followed by a curing treatment, thereby creating a laminate of substrate layer (25 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (40 μm thick). Chemical surface treatment was performed on both surfaces of the aluminum alloy foil. The chemical surface treatment of aluminum alloy foil is carried out as follows: with a chromium coating amount of 10 mg / m². 2 (Drying quality) The aluminum alloy foil is chemically surface-treated by applying a treatment solution containing phenolic resin, chromium fluoride compound and phosphoric acid to both surfaces of the aluminum alloy foil using a roller coating method, followed by sintering.

[0197] Next, maleic anhydride-modified polypropylene (23 μm thick) as an adhesive layer and random polypropylene (23 μm thick) as a hot-melt resin layer are co-extruded onto the barrier layer of each of the above-obtained laminates. After the adhesive layer / hot-melt resin layer is laminated on the barrier layer, it is cured to obtain a laminate (total thickness 114 μm) consisting of a substrate layer (25 μm thick), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (23 μm), and a hot-melt resin layer (23 μm) stacked sequentially from the outside.

[0198] Example 4

[0199] As the substrate layer, a stretched nylon (ONy) film (20 μm thick) was prepared. As described later, for the stretched nylon film used in Example 4, the stretching ratio and heat setting temperature were changed, and the crystallization index was adjusted to the values ​​recorded in Table 1. The stretched nylon film has a coating (a coating obtained by coating a polyester polyurethane containing lubricant with a thickness of 300 nm or less) on the surface opposite to the barrier layer, and a coating (a coating obtained by coating a polyester polyurethane with a thickness of 300 nm or less) on the surface on the barrier layer side. As the barrier layer, an aluminum alloy foil (JIS H4160:1994A8021H-O (35 μm thick)) was prepared. Next, an adhesive (two-component polyurethane adhesive) was applied to one surface of the aluminum alloy foil and dried. Next, the adhesive on the barrier layer was laminated to the substrate layer using a dry lamination method, followed by a curing treatment to create a laminate of substrate layer (20 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (35 μm thick). Chemical surface treatment was performed on both surfaces of the aluminum alloy foil. The chemical surface treatment of the aluminum alloy foil was carried out as follows: chromium coating amount of 10 mg / m²... 2 The aluminum alloy foil was chemically surface-treated by applying a treatment solution containing phenolic resin, chromium fluoride compound and phosphoric acid to both surfaces of the aluminum alloy foil using a roller coating method, followed by sintering.

[0200] Next, maleic anhydride-modified polypropylene (15 μm thick) as an adhesive layer and random polypropylene (15 μm thick) as a hot-melt resin layer are co-extruded onto the barrier layer of each of the above-obtained laminates. After the adhesive layer / hot-melt resin layer is laminated on the barrier layer, it is cured to obtain a laminate (total thickness 88 μm) consisting of a substrate layer (20 μm thick), an adhesive layer (3 μm), a barrier layer (35 μm), an adhesive layer (15 μm), and a hot-melt resin layer (15 μm) stacked sequentially from the outside.

[0201] Example 5

[0202] As the substrate layer, a stretched nylon (ONy) film (20 μm thick) was prepared. The stretched nylon film used in Example 5 was the same as that used in Example 4. The stretched nylon film had a coating (a coating of polyester polyurethane containing lubricant with a thickness of less than 300 nm) on the surface opposite to the barrier layer, and a coating (a coating of polyester polyurethane with a thickness of less than 300 nm) on the surface of the barrier layer side. As the barrier layer, an aluminum alloy foil (JISH4160:1994A8021H-O (30 μm thick)) was prepared. Next, an adhesive (two-component polyurethane adhesive) was applied to one surface of the aluminum alloy foil and dried. Then, the adhesive on the barrier layer was laminated to the substrate layer using a dry lamination method, and a curing treatment was performed to produce a laminate of substrate layer (20 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (30 μm thick). Chemical surface treatment was performed on both surfaces of the aluminum alloy foil. The chemical surface treatment of the aluminum alloy foil was carried out according to the following method: the chromium coating amount was 10 mg / m². 2 The aluminum alloy foil was chemically surface-treated by applying a treatment solution containing phenolic resin, chromium fluoride compound and phosphoric acid to both surfaces of the aluminum alloy foil using a roller coating method, followed by sintering.

[0203] Next, maleic anhydride-modified polypropylene (14 μm thick) as an adhesive layer and random polypropylene (10 μm thick) as a hot-melt resin layer are co-extruded onto the barrier layer of each of the above-obtained laminates. After the adhesive layer / hot-melt resin layer is laminated on the barrier layer, it is cured to obtain a laminate (total thickness 77 μm) consisting of a substrate layer (20 μm thick), an adhesive layer (3 μm), a barrier layer (30 μm), an adhesive layer (14 μm), and a hot-melt resin layer (10 μm) stacked sequentially from the outside.

[0204] Example 6

[0205] Except for using a stretched nylon (ONy) film with a coating (a coating obtained by coating polyester polyurethane with a thickness of less than 300 nm) on the surface of the barrier layer as the substrate layer, the same procedure as in Example 1 was followed to obtain a laminate (total thickness 114 μm) consisting of a substrate layer (thickness 25 μm), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (23 μm), and a thermosetting resin layer (23 μm) stacked sequentially from the outside.

[0206] Example 7

[0207] As the substrate layer, a stretched nylon (ONy) film (20 μm thick) was prepared. The stretched nylon film used in Example 7 was the same as that used in Example 4. As the barrier layer, an aluminum alloy foil (JIS H4160:1994A8021H-O (35 μm thick)) was prepared. Next, using an adhesive (a two-component polyurethane adhesive containing carbon black), the barrier layer and the substrate layer were laminated using a dry lamination method, followed by a curing treatment, thereby creating a laminate of substrate layer (20 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (35 μm thick). Chemical surface treatment was performed on both surfaces of the aluminum alloy foil. The chemical surface treatment of the aluminum alloy foil was performed by the following method: chromium coating amount of 10 mg / m³... 2 The aluminum alloy foil was chemically surface-treated by applying a treatment solution containing phenolic resin, chromium fluoride compound and phosphoric acid to both surfaces of the aluminum alloy foil using a roller coating method, followed by sintering.

[0208] Next, maleic anhydride-modified polypropylene (15 μm thick) as an adhesive layer and random polypropylene (15 μm thick) as a hot-melt resin layer are co-extruded onto the barrier layer of each of the above-obtained laminates, thereby stacking an adhesive layer / hot-melt resin layer on the barrier layer to obtain a laminate consisting of a substrate layer (20 μm thick), an adhesive layer (3 μm), a barrier layer (35 μm), an adhesive layer (15 μm), and a hot-melt resin layer (15 μm) stacked sequentially. Next, a resin (a two-component polyurethane resin containing silica particles and resin beads) for forming a rough layer as a surface cover layer is coated on the surface of the stretched nylon film of the obtained laminate with a thickness of 3 μm. After curing, a laminate with a total thickness of 91 μm is obtained, consisting of a surface cover layer (thickness 3 μm), a substrate layer (thickness 20 μm), an adhesive layer (3 μm), a barrier layer (35 μm), an adhesive layer (15 μm), and a heat-melting resin layer (15 μm) stacked sequentially from the outside.

[0209] Example 8

[0210] As the substrate layer, a stretched nylon (ONy) film (20 μm thick) was prepared. The stretched nylon film used in Example 8 was the same as that used in Example 4. As the barrier layer, an aluminum alloy foil (JIS H4160:1994A8021H-O (40 μm thick)) was prepared. Next, an adhesive (two-component polyurethane adhesive) was coated on one surface of the aluminum alloy foil and dried. Then, the adhesive on the barrier layer was laminated to the substrate layer using a dry lamination method, and a curing treatment was performed to create a laminate of substrate layer (20 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (40 μm thick). Chemical surface treatment was performed on both surfaces of the aluminum alloy foil. The chemical surface treatment of the aluminum alloy foil was performed as follows: the coating amount of chromium was 10 mg / m 2 The aluminum alloy foil was chemically surface-treated by applying a treatment solution containing phenolic resin, chromium fluoride compound and phosphoric acid to both surfaces of the aluminum alloy foil using a roller coating method, followed by sintering.

[0211] Next, maleic anhydride-modified polypropylene (14 μm thick) as an adhesive layer and random polypropylene (10 μm thick) as a hot-melt resin layer are co-extruded onto the barrier layer of each of the above-obtained laminates. After the adhesive layer / hot-melt resin layer is laminated on the barrier layer, it is cured to obtain a laminate (total thickness 87 μm) consisting of a substrate layer (20 μm thick), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (14 μm), and a hot-melt resin layer (10 μm) stacked sequentially from the outside.

[0212] Example 9

[0213] As the substrate layer, a stretched nylon (ONy) film (20 μm thick) was prepared. The stretched nylon film used in Example 9 was the same as that used in Example 4. As the barrier layer, an aluminum alloy foil (JIS H4160:1994A8021H-O (40 μm thick)) was prepared. Next, using an adhesive (a two-component polyurethane adhesive containing carbon black), the barrier layer and the substrate layer were laminated by dry lamination, followed by curing treatment, thereby creating a laminate of substrate layer (20 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (40 μm thick). Chemical surface treatment was performed on both surfaces of the aluminum alloy foil. The chemical surface treatment of the aluminum alloy foil was performed as follows: with a chromium coating amount of 10 mg / m 2 The aluminum alloy foil was chemically surface-treated by applying a treatment solution containing phenolic resin, chromium fluoride compound and phosphoric acid to both surfaces of the aluminum alloy foil using a roller coating method, followed by sintering.

[0214] Next, maleic anhydride-modified polypropylene (14 μm thick) as an adhesive layer and random polypropylene (10 μm thick) as a hot-melt resin layer are co-extruded onto the barrier layer of each of the above-obtained laminates, thereby stacking an adhesive layer / hot-melt resin layer on the barrier layer to obtain a laminate consisting of a substrate layer (20 μm thick), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (14 μm), and a hot-melt resin layer (10 μm) stacked sequentially. Next, a resin (a two-component polyurethane resin containing silica particles and resin beads) for forming a rough layer as a surface cover layer is coated on the surface of the stretched nylon film of the obtained laminate with a thickness of 3 μm. After curing, a laminate with a total thickness of 90 μm is obtained, consisting of a surface cover layer (thickness 3 μm), a substrate layer (thickness 20 μm), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (14 μm), and a heat-melting resin layer (10 μm) stacked sequentially from the outside.

[0215] Example 10

[0216] As the substrate layer, a stretched nylon (ONy) film (20 μm thick) was prepared. The stretched nylon film used in Example 10 was the same as that used in Example 4. As the barrier layer, an aluminum alloy foil (JIS H4160:1994A8021H-O (40 μm thick)) was prepared. Next, an adhesive (two-component polyurethane adhesive) was coated on one surface of the aluminum alloy foil and dried. Then, the adhesive on the barrier layer was laminated to the substrate layer using a dry lamination method, and a curing treatment was performed to create a laminate of substrate layer (20 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (40 μm thick). Chemical surface treatment was performed on both surfaces of the aluminum alloy foil. The chemical surface treatment of the aluminum alloy foil was performed as follows: the coating amount of chromium was 10 mg / m 2 The aluminum alloy foil was chemically surface-treated by applying a treatment solution containing phenolic resin, chromium fluoride compound and phosphoric acid to both surfaces of the aluminum alloy foil using a roller coating method, followed by sintering.

[0217] Next, maleic anhydride-modified polypropylene (15 μm thick) as an adhesive layer and random polypropylene (15 μm thick) as a hot-melt resin layer are co-extruded onto the barrier layer of each of the above-obtained laminates. After the adhesive layer / hot-melt resin layer is laminated on the barrier layer, it is cured to obtain a laminate (total thickness 93 μm) consisting of a substrate layer (20 μm thick), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (15 μm), and a hot-melt resin layer (15 μm) stacked sequentially from the outside.

[0218] Example 11

[0219] As the substrate layer, a stretched nylon (ONy) film (20 μm thick) was prepared. The stretched nylon film used in Example 11 was the same as that used in Example 4. As the barrier layer, an aluminum alloy foil (JIS H4160:1994A8021H-O (40 μm thick)) was prepared. Next, using an adhesive (a two-component polyurethane adhesive containing carbon black), the barrier layer and the substrate layer were laminated by dry lamination, followed by curing treatment, thereby creating a laminate of substrate layer (20 μm thick) / adhesive layer (3 μm thick after curing) / barrier layer (40 μm thick). Chemical surface treatment was performed on both surfaces of the aluminum alloy foil. The chemical surface treatment of the aluminum alloy foil was performed as follows: with a chromium coating amount of 10 mg / m 2 (Drying quality) Method: A chemical surface treatment of aluminum alloy foil is performed by coating two surfaces of the aluminum alloy foil with a treatment solution containing phenolic resin, chromium fluoride compound and phosphoric acid using a roller coating method, followed by sintering.

[0220] Next, maleic anhydride-modified polypropylene (14 μm thick) as an adhesive layer and random polypropylene (10 μm thick) as a hot-melt resin layer are co-extruded onto the barrier layer of each of the above-obtained laminates, thereby stacking an adhesive layer / hot-melt resin layer on the barrier layer to obtain a laminate consisting of a substrate layer (20 μm thick), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (15 μm), and a hot-melt resin layer (15 μm) stacked sequentially. Next, a resin (a two-component polyurethane resin containing silica particles and resin beads) for forming a rough layer as a surface cover layer is coated on the surface of the stretched nylon film of the obtained laminate with a thickness of 3 μm. After curing, a laminate with a total thickness of 96 μm is obtained, consisting of a surface cover layer (thickness 3 μm), a substrate layer (thickness 20 μm), an adhesive layer (3 μm), a barrier layer (40 μm), an adhesive layer (15 μm), and a heat-melting resin layer (15 μm) stacked sequentially from the outside.

[0221] <Determination of the Crystallization Index of the Substrate Layer of Outer Packaging Material for Energy Storage Devices>

[0222] The energy storage device was cut into 100mm × 100mm squares using the outer packaging material to prepare samples. Infrared absorption spectroscopy was performed on the surface of the stretched nylon film located on the outer side of the obtained samples using the ATR measurement mode of a Nicolet iS10FT-IR (Thermo Fisher Scientific) at 25°C and 50% relative humidity. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of the nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ from a crystallization-independent point.-1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. Measurements were performed for Examples 7, 9, and 11 before the application of the surface coating. The results are shown in Table 1.

[0223] (Measurement conditions)

[0224] Method: macroATR method;

[0225] Wavenumber resolution: 8cm -1 ;

[0226] Total number of times: 32;

[0227] Detector: DTGS detector;

[0228] ATR prism: Ge;

[0229] Angle of incidence: 45°;

[0230] Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The distance between them is obtained by approximation using a straight line.

[0231] Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range;

[0232] Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

[0233] <Determination of the Crystallization Index of Stretched Nylon Film>

[0234] The stretched nylon film used as the substrate layer of the outer packaging material for the energy storage device was cut into 100mm × 100mm squares to prepare samples. Infrared absorption spectroscopy was performed on the surface of the obtained samples using the ATR measurement mode of a Nicoleti S10 FT-IR spectrometer manufactured by Thermo Fisher Scientific at an environment of 25°C and 50% relative humidity. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α crystals of the nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ from a crystallization-independent point. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallization index. The results are shown in Table 1.

[0235] (Measurement conditions)

[0236] Method: macroATR method;

[0237] Wavenumber resolution: 8cm -1 ;

[0238] Total number of times: 32;

[0239] Detector: DTGS detector;

[0240] ATR prism: Ge;

[0241] Angle of incidence: 45°;

[0242] Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The distance between them is obtained by approximation using a straight line.

[0243] Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range;

[0244] Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

[0245] <Stripping Test of Energy Storage Device>

[0246] The following method was used to conduct a stripping test on the energy storage device. (Refer to...) Figures 5 to 8 Let me explain. First, refer to... Figure 5 The method for preparing samples for stripping tests on energy storage devices is described. For example... Figure 5 As shown in Figure a, the outer packaging material for the energy storage device is cut into a rectangular shape with a length (MD) of 200mm and a width (TD) of 90mm. Next, using a molding die (female mold) with a diameter of 55mm (MD) × 32mm (TD) and a corresponding molding die (male mold), a cold-rolling process is performed at a depth of 5.0mm from the thermosetting resin layer side, 15mm from the short side of the outer packaging material for the energy storage device, to form a recess M. Figure 5 (The area enclosed by the dashed line in section a). Next, insert an acrylic sheet with a length of 55mm, a width of 32mm, and a thickness of 5mm into recess M ( Figure 5 b, c). Next, with the recess M as the inside, fold the formed energy storage device in half along the TD direction using the outer packaging material at the crease P (along the short side of the recess M). Figure 5 d). Next, along the periphery of the recess M, for the portions where the heat-fused resin layers overlap, seal the recess M by heat-sealing at three points along MD and TD (190°C, 3 seconds, surface pressure 1 MPa). Figure 5 e). In Figure 5 In equation e, the colored region S is the heat-sealed portion. Next, as... Figure 5 As shown in f, along the recess M, the sample 12 is trimmed to a length (MD) of 60 mm and a width (TD) of 37 mm to produce a stripping test for the energy storage device. Figure 6 Side view of sample 12 ( Figure 6 a) and top view ( Figure 6 b).

[0247] Next, as Figure 7 As shown in the schematic diagram, three double-sided adhesive tapes (7.5 mm wide and 55 mm long) are attached along the longitudinal direction (MD) at both ends and the center of the surface of sample 12 on the top view side (the side opposite to the surface forming the recess M). The peel strength of the double-sided adhesive tapes relative to the object is measured using a method described later.

[0248] Next, sample 12, with double-sided tape attached, was adhered to a stainless steel plate and cured at 60°C for 24 hours. The stainless steel plate is considered the casing of the energy storage device secured using double-sided tape. Then, as... Figure 8 As shown in the schematic diagram, sample 12 was carefully peeled off from the stainless steel plate using a metal scraper. The presence of pores in the peeled sample 12 was visually inspected. For each of the three samples, the peel test of the energy storage device was evaluated according to the following criteria. Figure 8 As shown, the stripping of the energy storage device was performed by applying a force laterally (TD) from sample 12. The results are shown in Table 1.

[0249] A: None of the three samples had holes.

[0250] B: One or two samples have holes opened.

[0251] C: All three samples had holes made.

[0252] [Table 1]

[0253]

[0254] The outer packaging materials for the energy storage devices in Examples 1-11 are composed of a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially from the outside. The substrate layer comprises a polyamide film, and the crystallinity index of the polyamide film, measured from the outside of the substrate layer using the ATR method of Fourier transform infrared spectroscopy, is 1.50 or higher. Furthermore, the crystallinity index of the polyamide film used in the substrate layer of the outer packaging materials for the energy storage devices in Examples 1-11, measured using the ATR method of Fourier transform infrared spectroscopy, is 1.50 or higher. It can be seen that the outer packaging materials for the energy storage devices in Examples 1-11 can effectively suppress damage to the outer packaging material when the energy storage device, secured by double-sided tape or the like, is peeled from the casing.

[0255] It is generally believed that the difference between the crystallinity index obtained by measuring the substrate layer of the outer packaging material for energy storage devices and the crystallinity index obtained by measuring the stretched nylon film is affected by the curing of the outer packaging material for energy storage devices. The crystallinity index values ​​of the stretched nylon films used in Comparative Examples 1 and 2 are much smaller than those in Examples 1-11, and the values ​​measured after forming the substrate layer of the outer packaging material for energy storage devices are much larger than those measured in the state of the stretched nylon film. However, in Comparative Examples 1 and 2, the crystallinity index of the polyamide film measured from the outside of the substrate layer did not reach 1.50 or higher due to the curing of the outer packaging material for energy storage devices, and the peel test evaluation of the energy storage device was worse than that of Examples 1-11.

[0256] (Determination of peel strength of double-sided tape)

[0257] Prepare the outer packaging material (15mm x 70mm) for the energy storage device used in Examples 1-11, the double-sided tape (7.5mm x 60mm), aluminum foil (35μm x 15mm x 150mm), double-sided adhesive tape (5mm x 60mm), and acrylic sheet (3mm x 50mm x 70mm). First, attach the surface of the stretched nylon film side of the outer packaging material for the energy storage device (for Examples 4 and 5, the surface of the coating on the stretched nylon film; for Examples 7, 9, and 11, the surface of the surface cover layer on the stretched nylon film) to one surface of the double-sided tape. Then, attach the aluminum foil to the other surface of the double-sided tape. Roll a 2kg roller back and forth once from above the aluminum foil to obtain a laminate P. Next, attach the acrylic sheet to one surface of the double-sided adhesive tape to obtain a laminate Q. Then, the surface of the heat-melting resin layer of the battery storage device outer packaging material of the laminate P was attached to the other surface of the double-sided adhesive tape for fixing the laminate Q, and pressed by hand, thereby obtaining a laminate R consisting of an acrylic board, double-sided adhesive tape for fixing, battery storage device outer packaging material, double-sided tape, and aluminum foil stacked in sequence, and this was used as the test sample M. The test sample M was stored in an environment at 60°C for 24 hours. Next, the surface of the stretch nylon film of the battery storage device outer packaging material and the end of the double-sided tape were peeled off by about 1 mm, and the starting part for measuring the peel strength was set. Next, the acrylic sheet of test sample M was fixed, and a tensile testing machine (Shimadzu Corporation, AG-Xplus (trade name)) was used to stretch the aluminum foil under the conditions of a stretch angle of 180°, a peel speed of 300 mm / min, and a peel distance of 50 mm or more, so that it peeled from the surface of the stretched nylon film of the outer packaging material of the energy storage device at the interface of the double-sided tape (from the starting part mentioned above). The peel strength was calculated as the average of the five peel strengths, including the peel strength at peel distances of 10 mm, 20 mm, 30 mm, and 40 mm, and the maximum peel strength between 10 and 40 mm. This average was taken as the peel strength (peel strength of double-sided tape relative to stretched nylon film (N / 7.5 mm)). The results are shown in Table 2.

[0258] Next, prepare the stainless steel plate (3mm thick × 50mm long × 70mm wide) and double-sided adhesive tape (7.5mm long × 60mm wide) used in the <Peel Test of the Energy Storage Device>, as well as the aforementioned aluminum foil (35μm thick × 15mm long × 150mm wide). Adhere the surface of the stainless steel plate to one surface of the double-sided adhesive tape, and then adhere the aluminum foil to the other surface of the double-sided adhesive tape. Roll a 2kg roller from above the aluminum foil, repeating the process once to obtain a laminate, which is used as test sample N. Test sample N is stored at 60°C for 24 hours. Then, peel approximately 1mm from the surface of the stainless steel plate to the end of the double-sided adhesive tape, setting the starting point for measuring the peel strength. Next, the stainless steel plate of test sample N was fixed, and a tensile testing machine (manufactured by Shimadzu Corporation, AG-Xplus (trade name)) was used to stretch the aluminum foil under the conditions of a tensile angle of 180°, a peel speed of 300 mm / min, and a peel distance of 50 mm or more, so that it peeled off from the stainless steel plate at the interface of the double-sided tape (from the starting part mentioned above). The average of the five peel strengths, including the peel strength at peel distances of 10 mm, 20 mm, 30 mm, and 40 mm and the maximum peel strength between 10 and 40 mm, was calculated as the peel strength (peel strength of double-sided tape relative to stainless steel plate (N / 7.5 mm)). The results are shown in Table 2.

[0259] [Table 2]

[0260]

[0261] As the results shown in Table 2 clearly demonstrate, the peel strength of the double-sided tape used in the <Peel Test of Energy Storage Devices> was equivalent to that of the stretched nylon film and stainless steel sheet.

[0262] As described above, the present invention provides an invention in the manner shown below.

[0263] Item 1. An outer packaging material for an energy storage device, comprising a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially from the outside.

[0264] The aforementioned substrate layer includes a polyamide film.

[0265] The crystallinity index of the polyamide film measured from the outside of the substrate layer using the ATR method of Fourier transform infrared spectroscopy is 1.50 or higher.

[0266] Item 2. The outer packaging material for the energy storage device as described in Item 1, wherein an adhesive layer is provided between the substrate layer and the barrier layer.

[0267] Item 3. The outer packaging material for the energy storage device as described in Item 1 or 2, wherein an adhesive layer is provided between the barrier layer and the heat-melting resin layer.

[0268] Item 4. A method for manufacturing an outer packaging material for an energy storage device, comprising the step of obtaining a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially stacked from the outside.

[0269] The aforementioned substrate layer includes a polyamide film.

[0270] The crystallinity index of the polyamide film measured from the outside of the substrate layer using the ATR method of Fourier transform infrared spectroscopy is 1.50 or higher.

[0271] Item 5. An energy storage device comprising an energy storage device element having at least a positive electrode, a negative electrode, and an electrolyte, housed in a package formed of an outer packaging material for an energy storage device as described in any one of items 1 to 3.

[0272] Item 6. A polyamide film used in the substrate layer of an outer packaging material for an energy storage device, which is composed of a laminate having at least a substrate layer, a barrier layer and a heat-melting resin layer, wherein the crystallinity index of the polyamide film, as measured by the ATR method of Fourier transform infrared spectroscopy, is 1.50 or higher.

[0273] Symbol Explanation

[0274] 1. Substrate layer, 2. Adhesive layer, 3. Barrier layer, 4. Hot melt resin layer, 5. Adhesive layer, 6. Surface covering layer, 10. Outer packaging material for energy storage device.

Claims

1. An outer packaging material for an energy storage device, characterized in that: It is composed of a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially from the outside. The substrate layer comprises a polyamide film. The polyamide film has a thickness of 20 μm. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

2. An outer packaging material for an energy storage device, characterized in that: It is composed of a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer sequentially from the outside. The substrate layer comprises a polyamide film. The polyamide film has a thickness of 20 μm. The thickness of the barrier layer is 40 μm. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

3. An outer packaging material for an energy storage device, characterized in that: It is composed of a laminate having, from the outside in, at least a surface covering layer, a substrate layer, a barrier layer, and a heat-melting resin layer. At least one of the surface and interior of the surface coating layer contains titanium oxide. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

4. An outer packaging material for an energy storage device, characterized in that: It is composed of a laminate having, from the outside in, at least a surface covering layer, a substrate layer, a barrier layer, and a heat-melting resin layer. At least one of the surface and interior of the surface coating layer contains silicon dioxide. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

5. An outer packaging material for an energy storage device, characterized in that: It is composed of a laminate having, from the outside in, at least a surface covering layer, a substrate layer, a barrier layer, and a heat-melting resin layer. At least one of the surface and interior of the surface covering layer contains kaolin. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

6. An outer packaging material for an energy storage device, characterized in that: It is composed of a laminate having, from the outside in, at least a surface covering layer, a substrate layer, a barrier layer, and a heat-melting resin layer. The surface coating layer contains at least two of the following: its surface and interior. The surface coating layer contains at least two of the following: 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, acrylate resin, cross-linked acrylic acid, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

7. An outer packaging material for an energy storage device, characterized in that: It is composed of a laminate having, from the outside in, at least a surface covering layer, a coating layer, a substrate layer, a barrier layer, and a heat-melting resin layer. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

8. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: An adhesive layer is provided between the substrate layer and the barrier layer.

9. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: An adhesive layer is provided between the barrier layer and the thermoplastic resin layer.

10. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: Lubricant is present on at least one of the surface and interior of the substrate layer.

11. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: Two or more lubricants are present on at least one of the surface and interior of the substrate layer.

12. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: Lubricant is present on at least one of the surface and interior of the heat-fusion resin layer.

13. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: Two or more lubricants are present on at least one of the surface and interior of the heat-fusion resin layer.

14. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: The heat-fusion resin layer is formed by using two or more layers of the same or different resins.

15. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: The crystallinity index of the polyamide film, measured from the outside of the substrate layer using the ATR method of Fourier transform infrared spectroscopy, is 1.65 or higher.

16. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: At least one of the following is present on the surface and inside the substrate layer: at least two of the following are selected from saturated fatty amides, unsaturated fatty amides, substituted amides, hydroxymethyl amides, saturated fatty diamides, unsaturated fatty diamides, fatty acid ester amides, and aromatic diamides.

17. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: A lubricant is present on the surface of the substrate layer. The lubricant is present in an amount of 3 mg / m³. 2 above.

18. The outer packaging material for the energy storage device as described in claim 1, characterized in that: The surface and interior of the heat-melting resin layer contain at least two or more of the following: saturated fatty amides, unsaturated fatty amides, substituted amides, hydroxymethyl amides, saturated fatty diamides, unsaturated fatty diamides, fatty acid ester amides, and aromatic diamides.

19. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: A lubricant is present on the surface of the heat-fusion resin layer. The lubricant is present in an amount of 10 mg / m³. 2 above.

20. The outer packaging material for an energy storage device as described in any one of claims 1 to 7, characterized in that: A surface cover layer is provided on the side of the substrate layer opposite to the barrier layer side.

21. A method for manufacturing an outer packaging material for an energy storage device, characterized in that: This includes the process of obtaining a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer stacked sequentially from the outside. The substrate layer comprises a polyamide film. The polyamide film has a thickness of 20 μm. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

22. A method for manufacturing an outer packaging material for an energy storage device, characterized in that: This includes the process of obtaining a laminate having at least a substrate layer, a barrier layer, and a heat-melting resin layer stacked sequentially from the outside. The substrate layer comprises a polyamide film. The polyamide film has a thickness of 20 μm. The thickness of the barrier layer is 40 μm. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

23. A method for manufacturing an outer packaging material for an energy storage device, characterized in that: This includes the process of obtaining a laminate having at least a surface cover layer, a substrate layer, a barrier layer, and a heat-melting resin layer stacked sequentially from the outside. At least one of the surface and interior of the surface coating layer contains titanium oxide. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

24. A method for manufacturing an outer packaging material for an energy storage device, characterized in that: This includes the process of obtaining a laminate having at least a surface cover layer, a substrate layer, a barrier layer, and a heat-melting resin layer stacked sequentially from the outside. At least one of the surface and interior of the surface coating layer contains silicon dioxide. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

25. A method for manufacturing an outer packaging material for an energy storage device, characterized in that: This includes the process of obtaining a laminate having at least a surface cover layer, a substrate layer, a barrier layer, and a heat-melting resin layer stacked sequentially from the outside. At least one of the surface and interior of the surface covering layer contains kaolin. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

26. A method for manufacturing an outer packaging material for an energy storage device, characterized in that: This includes the process of obtaining a laminate having at least a surface cover layer, a substrate layer, a barrier layer, and a heat-melting resin layer stacked sequentially from the outside. The surface coating layer contains at least two of the following: its surface and interior. The surface coating layer contains at least two of the following: 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, acrylate resin, cross-linked acrylic acid, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

27. A method for manufacturing an outer packaging material for an energy storage device, characterized in that: This includes the process of obtaining a laminated body having at least a surface cover layer, a coating layer, a substrate layer, a barrier layer, and a thermosetting resin layer stacked sequentially from the outside. The substrate layer comprises a polyamide film. Using the ATR method of Fourier transform infrared spectroscopy, the crystallinity index of the polyamide film, measured from the outside of the substrate layer with the surface of the polyamide film exposed, is 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

28. The method for manufacturing the outer packaging material for an energy storage device as described in claim 27, characterized in that: An adhesive layer is provided between the barrier layer and the thermoplastic resin layer. The adhesive layer and the thermoplastic resin layer are formed by co-extrusion lamination, hot lamination, sandwich lamination, or by applying the adhesive used to form the adhesive layer onto the barrier layer using solution coating and then laminating the pre-formed sheet-like thermoplastic resin layer onto the adhesive layer. The co-extrusion lamination method is a method of laminating a substrate layer, an adhesive layer, and a barrier layer sequentially by extruding the adhesive layer and a thermosetting resin layer onto the barrier layer of the laminated body. The sandwich lamination method is as follows: after forming a laminate containing a substrate layer, an adhesive layer, and a barrier layer in sequence, a molten adhesive layer flows between the barrier layer of the laminate and a pre-formed sheet-like thermoplastic resin layer, and the laminate is bonded to the thermoplastic resin layer using the adhesive layer.

29. An energy storage device, characterized in that: The energy storage device contains at least a positive electrode, a negative electrode, and an electrolyte in a package formed from the outer packaging material of the energy storage device according to any one of claims 1 to 20.

30. A polyamide film, characterized in that: It is used for the substrate layer of an outer packaging material for an energy storage device, which is composed of a laminate consisting of at least a substrate layer, a barrier layer, and a heat-melting resin layer. The polyamide film has a thickness of 20 μm. The polyamide film, measured by the ATR method using Fourier transform infrared spectroscopy, has a crystallinity index of 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

31. A polyamide film, characterized in that: It is used for the substrate layer of an outer packaging material for an energy storage device, which is composed of a laminate consisting of at least a substrate layer, a barrier layer, and a heat-melting resin layer. The polyamide film has a thickness of 20 μm. The thickness of the barrier layer is 40 μm. The polyamide film, measured by the ATR method using Fourier transform infrared spectroscopy, has a crystallinity index of 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

32. A polyamide film, characterized in that: It is used for the substrate layer of an outer packaging material for an energy storage device, which is composed of a laminate having at least a surface covering layer, a substrate layer, a barrier layer, and a heat-melting resin layer. At least one of the surface and interior of the surface coating layer contains titanium oxide. The polyamide film, measured by the ATR method using Fourier transform infrared spectroscopy, has a crystallinity index of 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

33. A polyamide film, characterized in that: It is used for the substrate layer of an outer packaging material for an energy storage device, which is composed of a laminate having at least a surface covering layer, a substrate layer, a barrier layer, and a heat-melting resin layer. At least one of the surface and interior of the surface coating layer contains silicon dioxide. The polyamide film, measured by the ATR method using Fourier transform infrared spectroscopy, has a crystallinity index of 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

34. A polyamide film, characterized in that: It is used for the substrate layer of an outer packaging material for an energy storage device, which is composed of a laminate having at least a surface covering layer, a substrate layer, a barrier layer, and a heat-melting resin layer. At least one of the surface and interior of the surface covering layer contains kaolin. The polyamide film, measured by the ATR method using Fourier transform infrared spectroscopy, has a crystallinity index of 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

35. A polyamide film, characterized in that: It is used for the substrate layer of an outer packaging material for an energy storage device, which is composed of a laminate having at least a surface covering layer, a substrate layer, a barrier layer, and a heat-melting resin layer. The surface coating layer contains at least two of the following: its surface and interior. The surface coating layer contains at least two of the following: 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, acrylate resin, cross-linked acrylic acid, cross-linked styrene, cross-linked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. The polyamide film, measured by the ATR method using Fourier transform infrared spectroscopy, has a crystallinity index of 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

36. A polyamide film, characterized in that: It is used for the substrate layer of an outer packaging material for an energy storage device, which is composed of a laminate having at least a surface covering layer, a coating layer, a substrate layer, a barrier layer, and a heat-melting resin layer. The polyamide film, measured by the ATR method using Fourier transform infrared spectroscopy, has a crystallinity index of 1.50 or higher. The method for determining the crystallinity index is as follows: The energy storage device was cut into 100mm × 100mm squares from the outer packaging material to prepare samples. For the surface of the polyamide film on the outer side of the obtained samples, infrared absorption spectroscopy was performed using the ATR measurement mode of FT-IR at 25°C and 50% relative humidity. A Nicoleti S10 instrument manufactured by Thermo Fisher Scientific was used as the apparatus. Based on the obtained absorption spectra, the absorption at 1200 cm⁻¹ from the α-crystals of nylon was measured. -1 The nearby peak intensity P and the absorption at 1370 cm⁻¹ are unrelated to crystallization. -1 The intensity ratio X = P / Q, calculated from the nearby peak intensity Q, is used as the crystallinity index. The measurement conditions are: Method: macroATR method; Wavenumber resolution: 8cm -1 ; Total number of times: 32; Detector: DTGS detector; ATR prism: Ge; Angle of incidence: 45°; Baseline: at wavenumber 1100cm -1 Up to 1400cm -1 The results are obtained by approximating the relationship with a straight line. Absorption peak intensity Y 1200 From wavenumber 1195cm -1 Up to 1205cm -1 The value is obtained by subtracting the baseline value from the maximum peak intensity within the range; Absorption peak intensity Y 1370 From wavenumber 1365cm -1 Up to 1375cm -1 The value is obtained by subtracting the baseline value from the maximum value of the peak intensity within the range.

37. The polyamide film according to any one of claims 30 to 36, characterized in that: The crystallinity index of the polyamide film, as measured by the ATR method of Fourier transform infrared spectroscopy, is above 1.65.

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