Exterior material for power storage device and power storage device using same

Abstract

To provide an exterior material for a power storage device in which a base material layer is less likely to float from a barrier layer even in a high temperature environment (for example, 150°C).SOLUTION: An exterior material for a power storage device includes at least a base material layer, an outer layer adhesive layer, a barrier layer, and a sealant layer in this order, and a difference between the coefficient of linear expansion of the base material layer at 20 to 150°C and the coefficient of linear expansion of the barrier layer at 20 to 150°C is 20×10-6 / °C or less in both the MD and TD directions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an exterior material for an electricity storage device and an electricity storage device using the same. [Background technology]

[0002] Known examples of power storage devices include secondary batteries such as lithium ion batteries, nickel metal hydride batteries, and lead storage batteries, as well as electrochemical capacitors such as electric double layer capacitors. Due to the miniaturization of portable devices or the limitations of installation space, there is a demand for further miniaturization of power storage devices, and lithium ion batteries with high energy density have attracted attention. Metal cans have traditionally been used as exterior materials for lithium ion batteries, but multilayer films that are lightweight, have high heat dissipation properties, and can be produced at low cost have come to be used.

[0003] A lithium ion battery using the above multilayer film as an exterior material is called a laminated lithium ion battery. The exterior material covers the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.) and prevents moisture from penetrating into the battery. A laminated lithium ion battery is manufactured, for example, by forming a recess in a part of the exterior material by cold forming, accommodating the battery contents in the recess, folding back the remaining part of the exterior material, and heat sealing the edges (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-101765 A Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, research and development of a power storage device called an all-solid-state battery is being carried out as a next-generation battery of lithium-ion batteries. An all-solid-state battery is characterized by using a solid electrolyte as an electrolytic material, rather than an organic electrolyte. While a lithium-ion battery cannot be used at temperatures higher than the boiling point temperature of the electrolyte (about 80°C), an all-solid-state battery can be used at temperatures exceeding 100°C, and the conductivity of lithium ions can be increased by operating the battery under high temperature conditions (for example, 100 to 150°C). In addition, when an all-solid-state battery is used, the space and cost required for a cooling system for cooling the battery can be reduced.

[0006] However, when a laminate-type all-solid-state battery is produced using the above-mentioned multilayer film as an exterior material, when the obtained all-solid-state battery is operated in a high-temperature environment, peeling may occur between the base material layer and the metal foil layer (barrier layer) of the exterior material, and the base material layer may rise up from the underlying metal foil layer (outer layer lifting). In particular, the deep-drawn portion of the exterior material is stretched during molding, so that the above-mentioned outer layer lifting is more likely to occur. When the outer layer lifting occurs, the strength of that portion decreases, and the exterior material may be torn or the like.

[0007] In addition to all-solid-state batteries, other power storage devices such as lithium ion capacitors that can be used at high temperatures are being developed. Therefore, the exterior material of the power storage device is required to be less susceptible to outer layer peeling even when the power storage device is used in a high-temperature environment.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide an exterior material for a storage battery device in which the base layer is less likely to separate from the barrier layer even in a high-temperature environment (e.g., 150°C), and an energy storage device using the same. [Means for solving the problem]

[0009] In order to achieve the above object, the present disclosure provides an exterior material for an electricity storage device, comprising at least a base material layer, an outer adhesive layer, a barrier layer, and a sealant layer in this order, wherein the difference between the linear expansion coefficient of the base material layer at 20 to 150°C and the linear expansion coefficient of the barrier layer at 20 to 150°C is 20×10 or less in both the MD and TD directions. -6 / °C or less.

[0010] When an exterior material is exposed to a high-temperature environment, the thermal expansion of the substrate layer and the barrier layer occurs at a level that cannot be ignored. The present inventors have found that if there is a difference in thermal expansion between the substrate layer and the barrier layer, a shear force is applied to the outer adhesive layer bonding the substrate layer and the barrier layer, causing cohesive failure or interfacial peeling of the outer adhesive layer, resulting in peeling between the substrate layer and the barrier layer (outer layer lifting). The present inventors have also found that the above problem can be solved by controlling the difference in the linear expansion coefficient, which is an index of thermal expansion of the substrate layer and the barrier layer, to a specific range. That is, according to the exterior material of the present disclosure, the difference between the linear expansion coefficient of the substrate layer at 20 to 150°C and the linear expansion coefficient of the barrier layer at 20 to 150°C is less than 20×10 in both the MD and TD directions. -6 / ° C. or less, it is possible to prevent the base layer from peeling off from the barrier layer even in a high-temperature environment (for example, 150° C.).

[0011] In the electrical storage device packaging material, the barrier layer may be an aluminum foil. This can improve the moldability of the packaging material and reduce material costs. In addition, by using an aluminum foil as the barrier layer, it is easy to control the difference in linear expansion coefficient between the base layer and the barrier layer.

[0012] In the packaging material for a power storage device, the linear expansion coefficient of the base material layer at 20 to 150° C. is −7×10 in both the MD and TD directions. -6 / ℃ or more 53×10 -6By setting the linear expansion coefficient of the base layer within the above range, it is easy to reduce the difference with the linear expansion coefficient of the barrier layer, and it is easy to further suppress the occurrence of outer layer lift-off in a high temperature environment. In addition, when the barrier layer is an aluminum foil, the linear expansion coefficient of the aluminum foil is 23×10 -6 / °C., by setting the linear expansion coefficient of the base layer within the above range, the difference with the linear expansion coefficient of the aluminum foil can be reduced.

[0013] In the electrical storage device packaging material, the base layer may be a biaxially oriented semi-aromatic polyamide film. The base layer of the electrical storage device packaging material may be a biaxially oriented nylon (Ny) film (linear expansion coefficient: 72 to 80×10 -6 / ℃), polyethylene terephthalate (PET) film (linear expansion coefficient: 65~76×10 -6 / °C), or a PET / Ny film in which they are laminated or coextruded, is generally used. However, although these films have good formability, the difference in linear expansion coefficient between them and a thin metal layer (e.g., aluminum foil) is large, and the outer layer is likely to lift up in a high-temperature environment. In contrast, a biaxially stretched semi-aromatic polyamide film can reduce the difference in linear expansion coefficient between them and a thin metal layer (e.g., aluminum foil), making it easy to suppress the occurrence of outer layer lift up in a high-temperature environment, and can impart good formability to the exterior material.

[0014] In the electrical storage device exterior material, the outer adhesive layer may be a layer formed using a polyester urethane adhesive. In the electrical storage device exterior material, the outer adhesive layer may have a thickness of 1 to 10 μm. When the outer adhesive layer is a layer formed using a polyester urethane adhesive, the heat resistance of the outer adhesive layer can be further improved, and the occurrence of outer layer lifting in a high temperature environment can be further suppressed. In addition, when the outer adhesive layer has a thickness of 1 μm or more, high adhesive strength is easily obtained, and stress relaxation of the shear force generated during thermal expansion of the base layer and the barrier layer in a high temperature environment is easily achieved. On the other hand, when the outer adhesive layer has a thickness of 10 μm or less, the moldability of the exterior material can be further improved, and the occurrence of outer layer lifting in a high temperature environment can be further suppressed.

[0015] The exterior material for a power storage device may be for an all-solid-state battery.

[0016] The present disclosure also provides an electric storage device including an electric storage device main body, a current extracting terminal extending from the electric storage device main body, and an exterior material for an electric storage device according to the present disclosure, the exterior material sandwiching the current extracting terminal and housing the electric storage device main body. The electric storage device may be an all-solid-state battery. Effect of the Invention

[0017] According to the present disclosure, it is possible to provide an exterior material for an electricity storage device in which the base layer is unlikely to separate from the barrier layer even in a high-temperature environment (for example, 150° C.), and an electricity storage device using the same. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic cross-sectional view of an exterior material for a power storage device according to an embodiment of the present disclosure. [Diagram 2] 1 is a schematic cross-sectional view of an exterior material for a power storage device according to an embodiment of the present disclosure. [Diagram 3] 1 is a perspective view of an electricity storage device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations are omitted. In addition, the dimensional ratios of the drawings are not limited to the ratios shown in the drawings.

[0020] [Exterior materials for power storage devices] Fig. 1 is a cross-sectional view showing a schematic diagram of an embodiment of the exterior material for a power storage device according to the present disclosure. As shown in Fig. 1, the exterior material (exterior material for a power storage device) 10 of this embodiment is a laminate including a base layer 11, an outer adhesive layer 12a provided on one side of the base layer 11, a barrier layer 13 having first and second corrosion prevention treatment layers 14a, 14b on both sides provided on the opposite side of the outer adhesive layer 12a from the base layer 11, an inner adhesive layer 12b provided on the opposite side of the barrier layer 13 from the outer adhesive layer 12a, and a sealant layer 16 provided on the opposite side of the inner adhesive layer 12b from the barrier layer 13. Here, the first corrosion prevention treatment layer 14a is provided on the surface of the barrier layer 13 facing the base layer 11, and the second corrosion prevention treatment layer 14b is provided on the surface of the barrier layer 13 facing the sealant layer 16. In the exterior packaging material 10, the base material layer 11 is the outermost layer and the sealant layer 16 is the innermost layer. That is, the exterior packaging material 10 is used with the base material layer 11 facing the exterior side of the electricity storage device and the sealant layer 16 facing the interior side of the electricity storage device.

[0021] In the packaging material 10 of the present embodiment, the difference between the linear expansion coefficient of the base layer 11 at 20 to 150° C. and the linear expansion coefficient of the barrier layer 13 at 20 to 150° C. is 20×10 in both the MD and TD directions. -6 / °C or less. In this specification, the linear expansion coefficient of the barrier layer 13 may be measured for the barrier layer 13 in a state where the first and second corrosion prevention treatment layers 14a, 14b are not provided, or may be measured for the barrier layer 13 in a state where the first and second corrosion prevention treatment layers 14a, 14b are provided. Since the thickness of the first and second corrosion prevention treatment layers 14a, 14b is extremely thin compared to the thickness of the barrier layer 13, the influence of the presence of the first and second corrosion prevention treatment layers 14a, 14b on the measured value of the linear expansion coefficient of the barrier layer 13 can be almost negligible. In the present disclosure, the linear expansion coefficient can be measured using a thermomechanical analyzer (TMA). Specific measurement conditions are as shown in the examples.

[0022] In the packaging material 10 of the present embodiment, the difference between the linear expansion coefficient of the base material layer 11 at 20 to 150° C. and the linear expansion coefficient of the barrier layer 13 at 20 to 150° C. is 15×10 in both the MD and TD directions, because this makes it easier to prevent the base material layer 11 from peeling off from the barrier layer 13 in a high-temperature environment (e.g., 150° C.). -6 / °C or less, and more preferably 10×10 -6 It is more preferable that the temperature is 100° C. or less.

[0023] Each layer constituting the packaging material 10 will now be described in detail.

[0024] <Base material layer 11> The base layer 11 provides heat resistance in the sealing process when manufacturing the electricity storage device and plays a role in suppressing the occurrence of pinholes that may occur during molding and distribution. In particular, in the case of an exterior material for a large-scale electricity storage device, the base layer 11 can also provide scratch resistance, chemical resistance, insulation, and the like.

[0025] The base layer 11 is preferably a layer made of a resin film formed from an insulating resin.

[0026] The difference in linear expansion coefficient between the substrate layer 11 and the barrier layer 13 is 20×10 -6 / °C or less. In addition, the base layer 11 is preferably a layer that can ensure good moldability. From the viewpoint of satisfying these requirements, the base layer 11 is preferably a layer made of a semi-aromatic polyamide film.

[0027] The semi-aromatic polyamide constituting the semi-aromatic polyamide film is a copolymer of a dicarboxylic acid component and a diamine component, and contains an aromatic group in the dicarboxylic acid component or the diamine component. The semi-aromatic polyamide has high heat resistance. In addition, the semi-aromatic polyamide can ensure good moldability and is also excellent in dimensional stability. By using the semi-aromatic polyamide film as the base layer 11, the difference in linear expansion coefficient with the barrier layer 13 can be reduced to 20×10 -6 / ° C. or less, and thus it is possible to form an exterior material for an electricity storage device in which the base layer 11 is less likely to separate from the barrier layer 13 even in a high-temperature environment (for example, 150° C.).

[0028] The dicarboxylic acid component constituting the semi-aromatic polyamide is preferably mainly composed of terephthalic acid. Examples of dicarboxylic acid components other than terephthalic acid include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, and octadecanedioic acid; and aromatic dicarboxylic acids such as 1,4-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,2-naphthalenedicarboxylic acid, and isophthalic acid. These may be used alone or in combination of two or more. The proportion of terephthalic acid in the dicarboxylic acid component is preferably 60 to 100 mol%.

[0029] The diamine component constituting the semi-aromatic polyamide is preferably mainly composed of an aliphatic diamine having 4 to 15 carbon atoms. Examples of the aliphatic diamine having 4 to 15 carbon atoms include 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, 4-methyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, and 1,15-pentadecanediamine. These may be used alone or in combination of two or more.

[0030] In the semi-aromatic polyamide, lactams such as ε-caprolactam, ζ-enantholactam, η-capryllactam, ω-laurolactam, etc. may be copolymerized.

[0031] From the viewpoint of heat resistance during heat sealing, the melting point (Tm) of the semi-aromatic polyamide is preferably at least 30° C. higher than the melting point of the sealant layer 16. The melting point of the semi-aromatic polyamide may be, for example, 280 to 350° C. The types and copolymerization ratios of the monomers constituting the semi-aromatic polyamide are preferably adjusted so that the melting point of the semi-aromatic polyamide is within the above range.

[0032] The resin film constituting the base layer 11 such as the semi-aromatic polyamide film may be a stretched film or an unstretched film, but is preferably a biaxially stretched film because good moldability is easily obtained. Examples of the stretching method for the biaxially stretched film include a sequential biaxial stretching method, a tubular biaxial stretching method, and a simultaneous biaxial stretching method. The biaxially stretched film is preferably one stretched by a simultaneous biaxial stretching method or a tubular biaxial stretching method because it is easy to reduce the difference between the linear expansion coefficient in the MD direction and the linear expansion coefficient in the TD direction and is easy to reduce the difference between the linear expansion coefficient of the barrier layer 13 in both the MD direction and the TD direction.

[0033] The base layer 11 may be a single layer film made of one type of resin film, or a laminated film made of two or more types of resin films.

[0034] The linear expansion coefficient of the base layer 11 at 20 to 150° C. is easily reduced from the linear expansion coefficient of the barrier layer in both the MD and TD directions, and the occurrence of outer layer lift-off in a high-temperature environment is easily suppressed. Therefore, the linear expansion coefficient of the base layer 11 is easily reduced from the linear expansion coefficient of the barrier layer in both the MD and TD directions. -6 / ℃ or more 53×10 -6 / °C or less, and 3×10 -6 / ℃ or more 43×10 -6 / °C or less, and more preferably 13×10 -6 / ℃ or more 33×10 -6 It is more preferable that the temperature is 100° C. or less.

[0035] The difference between the linear expansion coefficient of the base layer 11 in the MD direction at 20 to 150° C. and the linear expansion coefficient of the base layer 11 in the TD direction at 20 to 150° C. is 20×10 -6 / °C or less, and preferably 10×10 -6 It is more preferable that the temperature is 100° C. or less.

[0036] The thickness of the substrate layer 11 is preferably 5 to 50 μm, more preferably 6 to 40 μm, further preferably 10 to 30 μm, and particularly preferably 12 to 30 μm. When the thickness of the substrate layer 11 is 5 μm or more, the pinhole resistance and insulating properties of the packaging material for an electricity storage device 10 tend to be improved. If the thickness of the substrate layer 11 exceeds 50 μm, the total thickness of the packaging material for an electricity storage device 10 becomes large, which is undesirable because it may be necessary to reduce the electric capacity of the battery.

[0037] <Outer adhesive layer 12a> The outer adhesive layer 12a is a layer that bonds the base material layer 11 and the barrier layer 13. Specific examples of materials constituting the outer adhesive layer 12a include polyurethane resins in which a difunctional or higher isocyanate compound (polyfunctional isocyanate compound) is allowed to act on a base material such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol. Among polyurethane resins, polyester urethane resins using polyester polyol and difunctional or higher isocyanate compounds are preferred because they are more likely to prevent the outer layer from peeling off in a high-temperature environment.

[0038] The various polyols described above can be used alone or in combination of two or more kinds depending on the functions and performance required for the exterior material.

[0039] Depending on the performance required for the adhesive, various other additives and stabilizers may be blended with the polyurethane resin described above.

[0040] In the polyurethane adhesive used to form the outer adhesive layer 12a containing the above-mentioned polyurethane resin, the ratio (NCO / OH) of the number of isocyanato groups contained in the polyfunctional isocyanate compound to the number of hydroxyl groups contained in the polyol may be 2 to 60, 5 to 50, or 10 to 40. When this ratio is 2 or more, the adhesive strength between the base layer 11 and the barrier layer 13 in a high-temperature environment (for example, 150°C) can be further improved, and the lifting of the base layer 11 from the barrier layer 13 in a high-temperature environment is more easily suppressed. When the ratio is 60 or less, it is possible to prevent unreacted hydroxyl groups from remaining in excess, and it is easy to further improve the adhesive strength between the base layer 11 and the barrier layer 13 in both room temperature and high-temperature environments. The heat resistance of the cured product of the polyurethane adhesive (outer adhesive layer 12a) is improved by urea or biuret generated by the reaction of a trace amount of water contained in the air or the adhesive with the polyfunctional isocyanate compound. Therefore, the more polyfunctional isocyanate compound there is, the more these units there are, which tends to increase Tg and improve heat resistance.

[0041] The thickness of the outer adhesive layer 12a is not particularly limited, but is preferably 1 to 10 μm, more preferably 3 to 7 μm, from the viewpoint of obtaining the desired adhesive strength, followability, processability, etc. If the thickness of the outer adhesive layer 12a is 1 μm or more, high adhesive strength is easily obtained, and stress relaxation of the shear force generated during thermal expansion of the base layer 11 and the barrier layer 13 in a high-temperature environment is easily achieved. On the other hand, if the thickness of the outer adhesive layer is 10 μm or less, the moldability of the exterior material can be further improved, and the occurrence of outer layer lifting in a high-temperature environment is more easily suppressed.

[0042] <Barrier layer 13> The barrier layer 13 has a water vapor barrier property that prevents moisture from penetrating into the inside of the electricity storage device. The barrier layer 13 may also have extensibility for deep drawing. As the barrier layer 13, for example, various metal foils such as aluminum, stainless steel, copper, etc., or metal vapor deposition films, inorganic oxide vapor deposition films, carbon-containing inorganic oxide vapor deposition films, films provided with these vapor deposition films, etc. can be used. As the film provided with the vapor deposition film, for example, an aluminum vapor deposition film or an inorganic oxide vapor deposition film can be used. These can be used alone or in combination of two or more. As the barrier layer 13, a metal foil is preferable, and an aluminum foil is more preferable, from the viewpoints of mass (specific gravity), moisture resistance, processability, and cost. Furthermore, the linear expansion coefficient of aluminum foil at 20 to 150°C is 23×10 -6 / ° C., and the difference with the linear expansion coefficient of the base layer 11 can be easily reduced.

[0043] As the aluminum foil, a soft aluminum foil that has been annealed can be preferably used from the viewpoint of imparting desired ductility during molding, but it is more preferable to use an aluminum foil containing iron for the purpose of imparting further pinhole resistance and ductility during molding. The content of iron in the aluminum foil is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%, in 100 mass% of the aluminum foil. When the iron content is 0.1 mass% or more, an exterior material 10 having better pinhole resistance and ductility can be obtained. When the iron content is 9.0 mass% or less, an exterior material 10 having better flexibility can be obtained. As the aluminum foil, an untreated aluminum foil may be used, but it is preferable to use an aluminum foil that has been degreased in terms of imparting corrosion resistance. When the aluminum foil is degreased, the degreased treatment may be performed on only one side of the aluminum foil, or on both sides.

[0044] The thickness of the barrier layer 13 is not particularly limited, but taking into consideration the barrier properties, pinhole resistance, and processability, it is preferably 9 to 200 μm, and more preferably 15 to 100 μm.

[0045] <First and second corrosion prevention treatment layers 14a, 14b> The first and second corrosion prevention layers 14a, 14b are layers provided to prevent corrosion of the metal foil (metal foil layer) constituting the barrier layer 13. The first corrosion prevention layer 14a plays a role in increasing the adhesion between the barrier layer 13 and the outer adhesive layer 12a. The second corrosion prevention layer 14b plays a role in increasing the adhesion between the barrier layer 13 and the inner adhesive layer 12b. The first corrosion prevention layer 14a and the second corrosion prevention layer 14b may be layers of the same configuration or layers of different configurations. The first and second corrosion prevention layers 14a, 14b (hereinafter also simply referred to as "corrosion prevention layers 14a, 14b") are formed, for example, by degreasing treatment, hydrothermal conversion treatment, anodizing treatment, chemical conversion treatment, or a combination of these treatments.

[0046] Examples of the degreasing treatment include acid degreasing and alkaline degreasing. Examples of the acid degreasing include a method using an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, or hydrofluoric acid alone or a mixture of these. In addition, by using an acid degreasing agent in which a fluorine-containing compound such as monosodium ammonium difluoride is dissolved in the inorganic acid as described above, not only can the aluminum be degreased, but also a passive aluminum fluoride can be formed, which is effective in terms of corrosion resistance, particularly when an aluminum foil is used for the barrier layer 13. Examples of the alkaline degreasing include a method using sodium hydroxide or the like.

[0047] An example of the hydrothermal modification treatment is a boehmite treatment in which an aluminum foil is immersed in boiling water containing added triethanolamine.

[0048] An example of the anodizing treatment is an alumite treatment.

[0049] The chemical conversion treatment may be of the immersion type or the coating type. Examples of the immersion type chemical conversion treatment include chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, strontium hydroxide treatment, cerium treatment, ruthenium treatment, and various chemical conversion treatments consisting of a mixture of these. On the other hand, examples of the coating type chemical conversion treatment include a method in which a coating agent having corrosion prevention properties is applied onto the barrier layer 13.

[0050] When forming at least a part of the corrosion prevention layer by any of these corrosion prevention treatments, namely, hydrothermal conversion treatment, anodizing treatment, and chemical conversion treatment, it is preferable to perform the above-mentioned degreasing treatment in advance. Note that, when using a degreased metal foil, such as a metal foil that has been subjected to an annealing process, as the barrier layer 13, there is no need to perform a degreasing treatment again in forming the corrosion prevention layers 14a and 14b.

[0051] The coating agent used in the spray-type chemical conversion treatment preferably contains trivalent chromium. The coating agent may also contain at least one polymer selected from the group consisting of cationic polymers and anionic polymers, which will be described later.

[0052] Among the above treatments, particularly in hydrothermal conversion treatment and anodization treatment, the aluminum foil surface is dissolved by a treatment agent to form an aluminum compound (boehmite, alumite) having excellent corrosion resistance. Therefore, since a bicontinuous structure is formed from the barrier layer 13 using the aluminum foil to the corrosion prevention treatment layers 14a, 14b, the above treatment is included in the definition of chemical conversion treatment. On the other hand, as described later, it is also possible to form the corrosion prevention treatment layers 14a, 14b by a pure coating method that is not included in the definition of chemical conversion treatment. As an example of this method, a method using a sol of a rare earth element oxide such as cerium oxide with an average particle size of 100 nm or less can be mentioned, which has an aluminum corrosion prevention effect (inhibitor effect) and is also environmentally friendly. By using this method, it is possible to impart a corrosion prevention effect to metal foils such as aluminum foils even with a general coating method.

[0053] Examples of the rare earth element oxide sol include sols using various solvents such as water-based, alcohol-based, hydrocarbon-based, ketone-based, ester-based, ether-based, etc. Among these, water-based sols are preferred.

[0054] In order to stabilize the dispersion of the rare earth oxide sol, inorganic acids such as nitric acid, hydrochloric acid, phosphoric acid, etc. or their salts, and organic acids such as acetic acid, malic acid, ascorbic acid, lactic acid, etc. are usually used as dispersion stabilizers. Among these dispersion stabilizers, phosphoric acid in particular is expected to (1) stabilize the dispersion of the sol, (2) improve adhesion to the barrier layer 13 by utilizing the aluminum chelating ability of phosphoric acid, and (3) improve the cohesive force of the corrosion prevention treatment layers 14a, 14b (oxide layers) by easily causing dehydration condensation of phosphoric acid even at low temperatures.

[0055] The corrosion prevention layers 14a and 14b formed from the rare earth oxide sol are aggregates of inorganic particles, and therefore may lose their cohesive strength even after the drying and curing process. Therefore, it is preferable that the corrosion prevention layers 14a and 14b in this case are compounded with an anionic polymer or a cationic polymer to compensate for the cohesive strength.

[0056] The corrosion prevention treatment layers 14a and 14b are not limited to the above-mentioned layers. For example, they may be formed using a treatment agent in which phosphoric acid and a chromium compound are mixed with a resin binder (such as aminophenol), as in the case of coating-type chromate, which is a known technology. By using this treatment agent, a layer having both corrosion prevention function and adhesion can be obtained. In addition, although it is necessary to consider the stability of the coating liquid, a coating agent in which a rare earth oxide sol and a polycationic polymer or a polyanionic polymer are mixed in advance into a one-component solution can be used to obtain a layer having both corrosion prevention function and adhesion.

[0057] The mass per unit area of ​​the corrosion prevention layers 14a and 14b is 0.005 to 0.200 g / m2 regardless of whether the layer has a multi-layer structure or a single-layer structure. 2 is preferable, and 0.010 to 0.100 g / m 2 It is more preferable that the mass per unit area is 0.005 g / m 2 If the mass per unit area is 0.200 g / m or more, it is easy to impart a corrosion prevention function to the barrier layer 13. 2 Even if the thickness exceeds 100 mm, the corrosion prevention function does not change much. On the other hand, when a rare earth oxide sol is used, if the coating is thick, the heat curing during drying may be insufficient, which may result in a decrease in cohesive force. The thickness of the corrosion prevention layers 14a and 14b can be calculated from their specific gravity.

[0058] From the viewpoint of easily maintaining the adhesion between the sealant layer and the barrier layer, the corrosion prevention treatment layers 14a, 14b may be in an embodiment containing, for example, cerium oxide, 1 to 100 parts by mass of phosphoric acid or a phosphate relative to 100 parts by mass of the cerium oxide, and a cationic polymer, or may be formed by subjecting the barrier layer 13 to a chemical conversion treatment, or may be formed by subjecting the barrier layer 13 to a chemical conversion treatment and contain a cationic polymer.

[0059] <Inner adhesive layer 12b> The inner adhesive layer 12b is a layer that bonds the barrier layer 13, on which the second corrosion prevention treatment layer 14b is formed, to the sealant layer 16. For the inner adhesive layer 12b, a general adhesive for bonding a barrier layer and a sealant layer can be used, and for example, the same adhesive as that for the outer adhesive layer 12a described above can be used.

[0060] The thickness of the inner adhesive layer 12b is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, processability, and the like, it is preferably 1 to 10 μm, and more preferably 3 to 7 μm.

[0061] <Sealant layer 16> The sealant layer 16 is a layer that provides heat sealing to the exterior material 10. Examples of the sealant layer 16 include resin films made of polyolefin resins or polyester resins. The resins constituting the sealant layer 16 (hereinafter also referred to as "base resins") may be used alone or in combination of two or more.

[0062] Examples of polyolefin resins include low-, medium- or high-density polyethylene; ethylene-α-olefin copolymers; polypropylene; block or random copolymers containing propylene as a copolymerization component; and propylene-α-olefin copolymers.

[0063] Examples of polyester resins include polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, and copolymers thereof.

[0064] The sealant layer 16 may contain a polyolefin-based elastomer. The polyolefin-based elastomer may be compatible with the above-mentioned base resin or may not be compatible with it, and may contain both a compatible polyolefin-based elastomer that is compatible and a non-compatible polyolefin-based elastomer that is not compatible with it. Being compatible (compatible system) means that the elastomer disperses in the base resin with a dispersed phase size of 1 nm or more and less than 500 nm. Not being compatible (non-compatible system) means that the elastomer disperses in the base resin with a dispersed phase size of 500 nm or more and less than 20 μm.

[0065] When the base resin is a polypropylene resin, the compatible polyolefin elastomer may be, for example, a propylene-butene-1 random copolymer, and the incompatible polyolefin elastomer may be, for example, an ethylene-butene-1 random copolymer. The polyolefin elastomers may be used alone or in combination of two or more.

[0066] Furthermore, the sealant layer 16 may contain, as additive components, for example, slip agents, antiblocking agents, antioxidants, light stabilizers, flame retardants, etc. The content of these additive components is preferably 5 parts by mass or less, assuming that the total mass of the sealant layer 16 is 100 parts by mass.

[0067] The thickness of the sealant layer 16 is not particularly limited, but from the viewpoint of achieving both a thin film and improved heat seal strength in a high-temperature environment, it is preferably in the range of 5 to 100 μm, more preferably in the range of 10 to 100 μm, and even more preferably in the range of 20 to 80 μm.

[0068] The sealant layer 16 may be either a single-layer film or a multi-layer film, and may be selected depending on the required function.

[0069] Although a preferred embodiment of the exterior material for a power storage device according to the present embodiment has been described in detail above, the present disclosure is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present disclosure as described in the claims.

[0070] For example, FIG. 1 shows a case where anti-corrosion treatment layers 14a, 14b are provided on both sides of the barrier layer 13, but only one of the anti-corrosion treatment layers 14a, 14b may be provided, or no anti-corrosion treatment layer may be provided.

[0071] While Fig. 1 shows a case in which the barrier layer 13 and the sealant layer 16 are laminated using the inner adhesive layer 12b, the barrier layer 13 and the sealant layer 16 may be laminated using an adhesive resin layer 15 as in an exterior packaging material 20 for an electricity storage device shown in Fig. 2. Furthermore, in the exterior packaging material 20 for an electricity storage device shown in Fig. 2, an inner adhesive layer 12b may be provided between the barrier layer 13 and the adhesive resin layer 15.

[0072] <Adhesive resin layer 15> The adhesive resin layer 15 is generally composed of an adhesive resin composition as a main component and additive components as necessary. The adhesive resin composition is not particularly limited, but preferably contains a modified polyolefin resin.

[0073] The modified polyolefin resin is preferably a polyolefin resin graft-modified with an unsaturated carboxylic acid derivative derived from an unsaturated carboxylic acid, an acid anhydride, or an ester thereof.

[0074] Examples of polyolefin resins include low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-α-olefin copolymer, homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymer.

[0075] The modified polyolefin resin is preferably a polyolefin resin modified with maleic anhydride. For example, "Admer" manufactured by Mitsui Chemicals, Inc. and "Modic" manufactured by Mitsubishi Chemical Corporation are suitable for the modified polyolefin resin. Since such modified polyolefin resins have excellent reactivity with various metals and polymers having various functional groups, the adhesive resin layer 15 can be given adhesion by utilizing the reactivity. In addition, the adhesive resin layer 15 may contain various additives such as various compatible and incompatible elastomers, flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers, as necessary.

[0076] The thickness of the adhesive resin layer 15 is not particularly limited, but from the viewpoints of stress relaxation and moisture permeability, it is preferably the same as or less than that of the sealant layer 16 .

[0077] In addition, in the exterior packaging material 20 for a storage battery device, the total thickness of the adhesive resin layer 15 and the sealant layer 16 is preferably in the range of 5 to 100 μm, and more preferably in the range of 20 to 80 μm, from the viewpoint of achieving both a thin film and improved heat seal strength in a high-temperature environment.

[0078] [Exterior material manufacturing method] Next, there will be described an example of a method for manufacturing the exterior packaging material 10 shown in Fig. 1. Note that the method for manufacturing the exterior packaging material 10 is not limited to the following method.

[0079] The manufacturing method of the exterior material 10 of this embodiment is roughly composed of a step of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, a step of bonding the base material layer 11 and the barrier layer 13 using the outer adhesive layer 12a, a step of further laminating a sealant layer 16 via the inner adhesive layer 12b to produce a laminate, and a step of aging the obtained laminate, if necessary.

[0080] (Laminating process of corrosion prevention treatment layers 14a, 14b on barrier layer 13) This step is a step of forming the corrosion prevention treatment layers 14a, 14b on the barrier layer 13. As described above, examples of the method include subjecting the barrier layer 13 to a degreasing treatment, a hydrothermal conversion treatment, an anodizing treatment, or a chemical conversion treatment, or applying a coating agent having corrosion prevention properties.

[0081] Furthermore, when the corrosion prevention treatment layers 14a, 14b are multiple layers, for example, a coating liquid (coating agent) constituting the lower corrosion prevention treatment layer (barrier layer 13 side) may be applied to the barrier layer 13 and baked to form a first layer, and then a coating liquid (coating agent) constituting the upper corrosion prevention treatment layer may be applied to the first layer and baked to form a second layer.

[0082] The degreasing treatment may be performed by spraying or immersion. The hydrothermal conversion treatment and anodizing treatment may be performed by immersion. The chemical conversion treatment may be performed by an appropriate method such as immersion, spraying, or coating, depending on the type of chemical conversion treatment.

[0083] Regarding the coating method of the coating agent having corrosion prevention properties, various methods such as gravure coating, reverse coating, roll coating, bar coating, etc. can be used.

[0084] As described above, the various treatments may be performed on either one or both sides of the metal foil, but in the case of one-sided treatment, the treated side is preferably the side on which the sealant layer 16 is laminated. If required, the surface of the base layer 11 may also be subjected to the above treatments.

[0085] The amount of coating agent applied to form the first layer and the second layer is 0.005 to 0.200 g / m 2 is preferable, and 0.010 to 0.100 g / m 2 is more preferred.

[0086] Furthermore, when dry curing is required, it can be performed at a base material temperature in the range of 60 to 300° C. depending on the drying conditions of the corrosion prevention treatment layers 14a and 14b used.

[0087] (Step of bonding the base layer 11 and the barrier layer 13) This step is a step of bonding the barrier layer 13 provided with the corrosion prevention treatment layers 14a, 14b to the base material layer 11 via the outer adhesive layer 12a. The bonding method may be dry lamination, non-solvent lamination, wet lamination, or the like, and the two are bonded together using the material constituting the outer adhesive layer 12a described above. The outer adhesive layer 12a is applied in a dry coating amount of 1 to 10 g / m2. 2 More preferably, the range is 2 to 7 g / m 2 It is set within the range.

[0088] (Laminating process of the inner adhesive layer 12b and the sealant layer 16) This step is a step of bonding the sealant layer 16 via the inner adhesive layer 12b to the second corrosion prevention treatment layer 14b side of the barrier layer 13. Examples of the bonding method include a wet process and dry lamination.

[0089] In the case of the wet process, a solution or dispersion of the adhesive constituting the inner adhesive layer 12b is applied onto the second corrosion prevention treatment layer 14b, and the solvent is removed at a predetermined temperature to form a dry film, or a baking process is performed as necessary after the dry film is formed. Then, the sealant layer 16 is laminated to produce the exterior material 10. Examples of the coating method include the various coating methods exemplified above. The preferred dry coating amount of the inner adhesive layer 12b is the same as that of the outer adhesive layer 12a.

[0090] In this case, the sealant layer 16 can be produced, for example, by a melt extrusion molding machine using a resin composition for forming a sealant layer that contains the above-mentioned components of the sealant layer 16. In the melt extrusion molding machine, the processing speed can be set to 80 m / min or more from the viewpoint of productivity.

[0091] (Aging process) This step is a step of aging (curing) the laminate. By aging the laminate, it is possible to promote adhesion between the barrier layer 13 / the second corrosion prevention treatment layer 14b / the inner adhesive layer 12b / the sealant layer 16. The aging treatment can be carried out at a temperature range of room temperature to 100° C. The aging time is, for example, 1 to 10 days.

[0092] In this manner, the exterior packaging material 10 of the present embodiment as shown in FIG. 1 can be manufactured.

[0093] Next, a description will be given of an example of a method for manufacturing the exterior material 20 shown in Fig. 2. Note that the method for manufacturing the exterior material 20 is not limited to the following method.

[0094] The manufacturing method of the exterior material 20 of this embodiment is generally configured to include a step of providing the corrosion prevention treatment layers 14a, 14b on the barrier layer 13, a step of bonding the base material layer 11 and the barrier layer 13 together using the outer layer adhesive layer 12a, a step of further laminating the adhesive resin layer 15 and the sealant layer 16 to prepare a laminate, and a step of heat treating the obtained laminate, as necessary. Note that the steps up to the step of bonding the base material layer 11 and the barrier layer 13 can be performed in the same manner as the manufacturing method of the exterior material 10 described above.

[0095] (Laminating Step of Adhesive Resin Layer 15 and Sealant Layer 16) This step is a step of forming an adhesive resin layer 15 and a sealant layer 16 on the second corrosion prevention treatment layer 14b formed in the previous step. The method includes a method of sand laminating the adhesive resin layer 15 together with the sealant layer 16 using an extrusion laminator. Furthermore, lamination is also possible by a tandem lamination method in which the adhesive resin layer 15 and the sealant layer 16 are extruded, or a co-extrusion method. In forming the adhesive resin layer 15 and the sealant layer 16, for example, each component is blended so as to satisfy the above-mentioned configuration of the adhesive resin layer 15 and the sealant layer 16. The above-mentioned resin composition for forming the sealant layer is used to form the sealant layer 16.

[0096] This process produces a laminate in which the layers are stacked in the following order: base layer 11 / outer adhesive layer 12a / first corrosion prevention treatment layer 14a / barrier layer 13 / second corrosion prevention treatment layer 14b / adhesive resin layer 15 / sealant layer 16, as shown in Figure 2.

[0097] The adhesive resin layer 15 may be laminated by directly extruding the materials dry-blended to have the above-mentioned material composition using an extrusion laminator. Alternatively, the adhesive resin layer 15 may be laminated by extruding the granulated material, which has been melt-blended in advance using a melt kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer, using an extrusion laminator.

[0098] The sealant layer 16 may be laminated by directly extruding the materials dry-blended to have the above-mentioned material composition as the constituents of the resin composition for forming the sealant layer using an extrusion laminator. Alternatively, the adhesive resin layer 15 and the sealant layer 16 may be laminated by a tandem lamination method in which the adhesive resin layer 15 and the sealant layer 16 are extruded using an extrusion laminator using a granulated product obtained by melt blending in advance using a melt kneading device such as a single screw extruder, a twin screw extruder, or a Brabender mixer, or by a co-extrusion method. Alternatively, a sealant monolayer may be formed in advance as a cast film using the resin composition for forming the sealant layer, and this film may be laminated together with an adhesive resin by a method of sand lamination. The forming speed (processing speed) of the adhesive resin layer 15 and the sealant layer 16 may be, for example, 80 m / min or more from the viewpoint of productivity.

[0099] (Heat treatment process) This step is a step of heat-treating the laminate. Heat-treating the laminate can improve adhesion between the barrier layer 13, the second corrosion prevention treatment layer 14b, the adhesive resin layer 15, and the sealant layer 16. As a method of heat treatment, it is preferable to treat at a temperature at least equal to or higher than the melting point of the adhesive resin layer 15.

[0100] In this manner, the exterior packaging material 20 of this embodiment as shown in FIG. 2 can be manufactured.

[0101] Although preferred embodiments of the exterior material for a power storage device according to the present disclosure have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present disclosure as described in the claims.

[0102] The exterior material for an electricity storage device according to the present disclosure can be suitably used as an exterior material for an electricity storage device such as, for example, a secondary battery such as a lithium ion battery, a nickel-metal hydride battery, and a lead-acid battery, and an electrochemical capacitor such as an electric double layer capacitor, etc. In particular, the exterior material for an electricity storage device according to the present disclosure is suitable as an exterior material for an all-solid-state battery using a solid electrolyte.

[0103] [Electricity storage device] FIG. 3 is a perspective view showing one embodiment of a power storage device produced using the above-mentioned exterior material. As shown in FIG. 3, the power storage device 50 includes a battery element (power storage device main body) 52, two metal terminals (current extraction terminals) 53 for extracting current from the battery element 52 to the outside, and an exterior material 10 that hermetically encloses the battery element 52. The exterior material 10 is the exterior material 10 according to the present embodiment described above. In the exterior material 10, the base material layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. That is, the exterior material 10 is configured to enclose the battery element 52 inside by folding one laminate film in two and heat-sealing it, or by overlapping and heat-sealing two laminate films, so that the base material layer 11 is on the outer side of the power storage device 50 and the sealant layer 16 is on the inner side of the power storage device 50. Note that the exterior material 20 may be used in place of the exterior material 10 in the power storage device 50.

[0104] Battery element 52 is formed by interposing an electrolyte between a positive electrode and a negative electrode. Metal terminal 53 is a part of a current collector taken out from exterior material 10, and is made of a metal foil such as copper foil or aluminum foil.

[0105] The electricity storage device 50 of this embodiment may be an all-solid-state battery. In this case, a solid electrolyte such as a sulfide-based solid electrolyte is used as the electrolyte of the battery element 52. Since the electricity storage device 50 of this embodiment uses the exterior material 10 of this embodiment, it is possible to suppress the occurrence of the base material layer peeling off from the barrier layer even when the electricity storage device 50 is used in a high-temperature environment (for example, 150°C). EXAMPLES

[0106] The present disclosure will be described more specifically below based on examples, but the present disclosure is not limited to the following examples.

[0107] [Materials used] The materials used in the examples and comparative examples are shown below.

[0108] <Base material layer> Semi-aromatic polyamides 1 to 4: Simultaneous biaxially stretched semi-aromatic polyamide films (thickness: 25 μm) having the linear expansion coefficients shown in Table 1 PBT: Polybutylene terephthalate film (manufactured by Toyobo Co., Ltd., product name: DE048, thickness: 15 μm) Nylon 6: Nylon 6 film (manufactured by Toyobo Co., Ltd., product name: N1102, thickness: 25 μm) PET / nylon 6: A laminated film of polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name: E5102, thickness: 12 μm) and nylon 6 film (manufactured by Idemitsu Unitech Co., Ltd., product name: G100)

[0109] <Outer adhesive layer> Polyester urethane: A polyester urethane adhesive was used, which was prepared by mixing polyester polyol (manufactured by Toyo-Morton, product name: TMK-55) and isocyanate (TDI-Adduct, manufactured by Toyo-Morton, product name: CAT-10L) and diluting with a solvent. PO-based: A polyolefin-based adhesive was used, which was prepared by blending Auroren 350S (product name) manufactured by Nippon Paper Industries Co., Ltd. and DYNAGRAND CR-410B (product name) manufactured by Toyo-Morton Co., Ltd. and diluting the mixture with a solvent.

[0110] <First corrosion prevention treatment layer (base layer side) and second corrosion prevention treatment layer (sealant layer side)> (CL-1): A sodium polyphosphate-stabilized cerium oxide sol was used, the solid content of which was adjusted to 10% by mass using distilled water as a solvent. The sodium polyphosphate-stabilized cerium oxide sol was obtained by mixing 100 parts by mass of cerium oxide with 10 parts by mass of sodium salt of phosphoric acid. (CL-2): A composition consisting of 90% by mass of "polyallylamine (manufactured by Nitto Boseki Co., Ltd.)" adjusted to a solid content concentration of 5% by mass using distilled water as a solvent, and 10% by mass of "polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation)" was used.

[0111] <Barrier layer (thickness: 40 μm)> Annealed and degreased soft aluminum foil (manufactured by Toyo Aluminum Co., Ltd., "Material 8079") was used.

[0112] <Inner adhesive layer (thickness: 3 μm)> The polyester urethane adhesive described above was used.

[0113] <Sealant layer (thickness: 75 μm)> A polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name: E5100) was used.

[0114] [Creating exterior materials] Example 1 First, a first and a second corrosion prevention treatment layer were provided on the barrier layer by the following procedure: (CL-1) was applied on both sides of the barrier layer in a dry coating amount of 70 mg / m 2 The layer was then coated by microgravure coating so that the thickness of the layer was 200 mm, and the layer was baked at 200° C. in a drying unit. Next, (CL-2) was applied onto the layer obtained in a dry coating amount of 20 mg / m 2 By applying the coating by microgravure coating so that the above-mentioned coating conditions were satisfied, a composite layer consisting of (CL-1) and (CL-2) was formed as the first and second corrosion prevention treatment layers. This composite layer exhibits corrosion prevention performance by combining the two types of materials, (CL-1) and (CL-2).

[0115] Next, the first corrosion prevention treatment layer side of the barrier layer provided with the first and second corrosion prevention treatment layers was attached to the base layer by dry lamination using a polyester urethane adhesive (outer adhesive layer). The lamination of the barrier layer and the base layer was performed by applying the polyester urethane adhesive to the surface of the barrier layer facing the first corrosion prevention treatment layer so that the thickness after curing would be the value shown in Table 1, drying at 80°C for 1 minute, laminating it with the base layer, and aging it at 80°C for 120 hours.

[0116] Next, the second corrosion prevention treatment layer side of the barrier layer provided with the first and second corrosion prevention treatment layers was attached to the sealant layer by dry lamination using a polyester urethane adhesive (inner adhesive layer). The lamination of the barrier layer and the sealant layer was performed by applying a polyester urethane adhesive to the surface of the barrier layer facing the second corrosion prevention treatment layer so that the thickness after curing was 3 μm, drying at 80° C. for 1 minute, laminating with the sealant layer, and aging at 80° C. for 120 hours. In this manner, an exterior material (a laminate of substrate layer / outer adhesive layer / first corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer / inner adhesive layer / sealant layer) was produced.

[0117] (Examples 2 to 5 and Comparative Examples 1 to 5) Exterior materials of Examples 2 to 5 and Comparative Examples 1 to 5 (laminates of substrate layer / outer adhesive layer / first corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer / inner adhesive layer / sealant layer) were produced in the same manner as in Example 1, except that the substrate layer and / or outer adhesive layer were changed to the configurations shown in Table 1. When a "PO-based" outer adhesive layer was used, the conditions for laminating the barrier layer and substrate layer were changed to drying at 100°C for 1 minute and aging at 40°C for 120 hours.

[0118] [Measurement of linear expansion coefficient] The substrate layer used in the examples and comparative examples, and the barrier layer after the provision of the corrosion prevention treatment layer, were cut to a size of 30 mm in MD direction × 5 mm in TD direction and 30 mm in TD direction × 5 mm in MD direction (both are measured in the longitudinal direction) to prepare test pieces. The longitudinal dimensional change of the obtained test pieces was measured using a thermomechanical analyzer (manufactured by Hitachi High-Tech Science Corporation, product name: TMA7100). The measurement conditions are as follows. Using the TMA curve obtained in the measurement at the second temperature rise, the average value of the change in length per 1°C in the temperature range from 20°C to 150°C was calculated as the linear expansion coefficient of the test pieces. The results are shown in Table 1. Table 1 also shows the difference in linear expansion coefficient between the substrate layer and the barrier layer. [Temperature conditions] (1) Heat from 20°C to 170°C at 10°C / min (first heat increase) (2) Decrease temperature from 170°C to 20°C at 10°C / min (3) Heat from 20°C to 170°C at 10°C / min (second heating) 〔load〕 40mN constant

[0119] [Evaluation of outer layer floating] The exterior materials obtained in the examples and comparative examples were cut into rectangular shapes of 120 mm in the TD direction × 200 mm in the MD direction, and placed in a molding device so that the sealant layer faced upward. The molding depth of the molding device was set to 4.0 mm, the holding pressure was set to 0.8 MPa, and cold molding was performed in an environment of room temperature 23 ° C and dew point temperature -35 ° C. The punch mold had a rectangular cross section of 80 mm × 70 mm, a punch radius (RP) of 1 mm on the bottom, and a punch corner radius (RCP) of 1 mm on the side. The die mold had a die radius (RD) of 1 mm on the upper surface of the opening. The clearance between the punch mold and the die mold was 170 μm. The molding area was approximately the center of one half of the cut exterior material divided at approximately the center in the longitudinal direction (MD direction), and the longitudinal direction of the punch mold was along the TD direction of the exterior material.

[0120] The samples deep-drawn under the above conditions were stored in an environment of 150°C for three days, and then the presence or absence of peeling of the base layer from the barrier layer (outer layer lifting) was checked. Furthermore, for samples in which no outer layer lifting occurred after three days of storage, the samples were stored in an environment of 150°C for an additional four days (total of seven days), and then the presence or absence of outer layer lifting was checked. The outer layer lifting was evaluated based on the following criteria. The evaluation results are shown in Table 1. An evaluation result of A or B is considered to be acceptable. A: No outer layer peeling occurred after storage for 7 days B: No outer layer peeling occurred after storage for 3 days C: After storage for 3 days, the outer layer peeled off.

[0121] [Table 1] [Industrial Applicability]

[0122] According to the present disclosure, there are provided an exterior material for an electricity storage device in which the base layer is unlikely to separate from the barrier layer even in a high-temperature environment (for example, 150° C.), and an electricity storage device using the same. [Explanation of symbols]

[0123] Reference Signs List 10, 20... exterior material for electricity storage device, 11... base material layer, 12a... outer adhesive layer, 12b... inner adhesive layer, 13... barrier layer, 14a... first corrosion prevention treatment layer, 14b... second corrosion prevention treatment layer, 15... adhesive resin layer, 16... sealant layer, 50... electricity storage device, 52... battery element, 53... metal terminal.

Claims

1. An exterior material for a power storage device comprising at least a base layer, an outer adhesive layer, a barrier layer, and a sealant layer in this order, The difference between the linear expansion coefficient of the base layer at 20 to 150° C. and the linear expansion coefficient of the barrier layer at 20 to 150° C. is 20×10 in both the MD and TD directions. －６ / °C or less, The exterior material for a power storage device, wherein the base material layer is a biaxially stretched semi-aromatic polyamide film.

2. The packaging material for a power storage device according to claim 1 , wherein the barrier layer is an aluminum foil.

3. The linear expansion coefficient of the base layer at 20 to 150° C. is −7×10 in both the MD and TD directions. －６ / ℃ or more 53 x 10 －６ The packaging material for an electricity storage device according to claim 1 or 2, wherein the temperature is 0.15 to 1.5° C. / ° C. or lower.

4. The exterior material for a storage battery device according to any one of claims 1 to 3, wherein the outer adhesive layer is a layer formed using a polyester urethane adhesive, and the outer adhesive layer has a thickness of 1 to 10 µm.

5. The exterior material for a storage battery device according to any one of claims 1 to 4, which is for an all-solid-state battery.

6. A power storage device main body; a current extracting terminal extending from the power storage device body; The exterior material for an electricity storage device according to any one of claims 1 to 5, which holds the current extracting terminal and houses the electricity storage device main body; A power storage device comprising:

7. The power storage device according to claim 6 , which is an all-solid-state battery.

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