Exterior material for energy storage devices and energy storage devices using the same

Abstract

Provided is an exterior material for a power storage device that is resistant to dielectric breakdown even in a high-temperature environment (for example, 150°C). The packaging material for an electricity storage device has a structure in which at least a base layer, an outer adhesive layer, a barrier layer, and a sealant layer are laminated in this order, and the ratio of the volume resistivity of the base layer in an environment of 23°C to that in an environment of 150°C (volume resistivity in an environment of 23°C / volume resistivity in an environment of 150°C) is 1×10 0 ~1×10 3 This is an exterior material for energy storage devices.

Description

[Technical Field]

[0001] The present disclosure relates to an exterior material for a power storage device and a power 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-acid batteries, as well as electrochemical capacitors such as electric double-layer capacitors. Due to the miniaturization of portable devices and limitations on installation space, there is a demand for further miniaturization of power storage devices, and lithium-ion batteries with high energy density have attracted attention. While metal cans have traditionally been used as the exterior materials for lithium-ion batteries, multilayer films have begun to be used, which are lightweight, have excellent heat dissipation properties, and can be produced at low cost.

[0003] Lithium-ion batteries that use the above multilayer film as an exterior material are called laminated lithium-ion batteries. The exterior material covers the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.) and prevents moisture from penetrating into the battery. Laminated lithium-ion batteries are manufactured, for example, by forming a recess in 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] Japanese Patent Application Laid-Open No. 2013-101765 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, research and development is being conducted on power storage devices known as all-solid-state batteries as the next generation of lithium-ion batteries. All-solid-state batteries are characterized by using a solid electrolyte rather than an organic electrolyte solution as the electrolyte. While lithium-ion batteries cannot be used at temperatures higher than the boiling point of the electrolyte (approximately 80°C), all-solid-state batteries can be used at temperatures exceeding 100°C, and the conductivity of lithium ions can be increased by operating them at high temperatures (e.g., 100 to 150°C). Furthermore, the use of all-solid-state batteries can reduce the space and cost required for a cooling system to cool the battery.

[0006] However, the present inventors have found that when a laminate-type all-solid-state battery is fabricated using the above-mentioned multilayer film as an exterior material, the insulating properties of the exterior material deteriorate when the resulting all-solid-state battery is operated in a high-temperature environment, resulting in a problem in that dielectric breakdown due to applied voltage is likely to occur. Current lithium-ion batteries are not used at high temperatures due to the use of an electrolyte, and therefore the above-mentioned problems with exterior materials when used in high-temperature environments have not been recognized as issues until now. Furthermore, since the extraction of high voltages by making all-solid-state batteries bipolar is also being considered, the importance of insulating properties in exterior materials is becoming even greater.

[0007] Furthermore, not only all-solid-state batteries but also other power storage devices such as lithium ion capacitors that can be used at high temperatures are being developed, and therefore, the exterior materials of the power storage devices are required to be resistant to dielectric breakdown even when the power storage devices are used in high-temperature environments.

[0008] The present disclosure has been made in view of the above-mentioned problems, and aims to provide an exterior packaging material for a power storage device that is resistant to dielectric breakdown even in a high-temperature environment (for example, 150°C), and a power storage device using the same. [Means for solving the problem]

[0009] In order to achieve the above object, the present disclosure provides an exterior packaging material for an electricity storage device having a structure in which at least a base material layer, an outer layer adhesive layer, a barrier layer, and a sealant layer are laminated in this order, wherein the ratio of the volume resistivity of the base material layer in an environment of 23°C to the volume resistivity in an environment of 150°C (volume resistivity in an environment of 23°C / volume resistivity in an environment of 150°C) is 1×10 0 ~1×10 3 The present invention provides an exterior material for an electricity storage device, which is

[0010] According to the above-described packaging material for a power storage device, by setting the ratio of the volume resistivity of the substrate layer at 23°C to the volume resistivity at 150°C (volume resistivity at 23°C / volume resistivity at 150°C) (hereinafter also referred to as the "resistance change ratio") within the above range, a rapid decrease in the volume resistivity of the substrate layer with increasing temperature can be suppressed, and dielectric breakdown can be suppressed in high-temperature environments (e.g., 150°C). Here, if the volume resistivity of the substrate layer decreases rapidly with increasing temperature, a packaging material designed to ensure sufficient insulation at or below the boiling point of the electrolyte in a conventional lithium-ion battery (approximately 80°C) will experience dielectric breakdown when used in a high-temperature environment (e.g., when used at 100 to 150°C). In contrast, by setting the resistance change ratio of the substrate layer within the above range, a packaging material designed to ensure sufficient insulation at or below approximately 80°C can be used as is in a high-temperature environment without dielectric breakdown.

[0011] In the packaging material for a power storage device, the volume resistivity of the base material layer in an environment of 23°C is 1×10 13 When the volume resistivity of the base material layer in a 23°C environment is within the above range and the resistance change ratio is within the above range, the occurrence of dielectric breakdown can be more sufficiently suppressed both when used at temperatures below about 80°C and when used in a high-temperature environment (for example, when used at 100 to 150°C).

[0012] In the packaging material for a power storage device, the volume resistivity of the base material layer in an environment of 150°C is 1×10 12When the volume resistivity of the base material layer in a 150°C environment is within the above range and the resistance change ratio is within the above range, the occurrence of dielectric breakdown can be more sufficiently suppressed both when used at temperatures below about 80°C and when used in a high-temperature environment (for example, when used at 100 to 150°C).

[0013] In the packaging material for a power storage device, the thickness of the base material layer is 35 μm or less, and a value obtained by multiplying the volume resistivity of the base material layer in a 150° C. environment by the thickness of the base material layer is 5×10 13 (Ω·m×μm) or more. By keeping the thickness of the base material layer within the above range, curling after molding of the packaging material can be suppressed, thereby preventing a decrease in handleability during heat sealing in a subsequent process. Furthermore, by keeping the value obtained by multiplying the thickness of this base material layer by the volume resistivity in a 150°C environment within the above range, the occurrence of dielectric breakdown can be more sufficiently suppressed both when used at temperatures below about 80°C and when used in high-temperature environments (for example, when used at 100 to 150°C).

[0014] In the packaging material for a power storage device, the base material layer may be a biaxially stretched film. When the base material layer is a biaxially stretched film, the formability of the packaging material for a power storage device can be further improved.

[0015] In the packaging material for a power storage device, the base material layer may be a semi-aromatic polyamide film. The semi-aromatic polyamide film is likely to have a resistance change ratio, a volume resistivity in a 23°C environment, and a volume resistivity in a 150°C environment within the above-mentioned specific ranges. Therefore, when the base material layer is a semi-aromatic polyamide film, the occurrence of dielectric breakdown can be more sufficiently suppressed both when used at about 80°C or less and when used in a high-temperature environment (for example, when used at 100 to 150°C).

[0016] In the packaging material for a power storage device, the outer adhesive layer may be a layer formed using a polyester urethane adhesive. By forming the outer adhesive layer using a polyester urethane adhesive, excellent adhesive strength can be maintained even in a high-temperature environment (e.g., 150°C).

[0017] The packaging material for a power storage device may be used for an all-solid-state battery.

[0018] The present disclosure also provides an electricity storage device including: an electricity storage device main body; a current extracting terminal extending from the electricity storage device main body; and an exterior material for an electricity storage device according to the present disclosure, the exterior material sandwiching the current extracting terminal and housing the electricity storage device main body. The electricity storage device may be an all-solid-state battery. [Effects of the Invention]

[0019] According to the present disclosure, it is possible to provide an exterior packaging material for a power storage device that is resistant to dielectric breakdown even in a high-temperature environment (for example, 150° C.), and a power storage device using the same. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic cross-sectional view of an exterior packaging material for a power storage device according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic cross-sectional view of an exterior packaging material for a power storage device according to an embodiment of the present disclosure. [Figure 3] 1 is a perspective view of an electricity storage device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0021] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

[0022] [Exterior materials for energy storage devices] Fig. 1 is a cross-sectional view schematically illustrating one embodiment of an exterior packaging material for a power storage device according to the present disclosure. As shown in Fig. 1, an exterior packaging material (exterior packaging material for a power storage device) 10 of this embodiment is a laminate comprising a substrate layer 11, an outer adhesive layer 12a provided on one side of the substrate layer 11, a barrier layer 13 provided on the side of the outer adhesive layer 12a opposite the substrate layer 11 and having first and second corrosion prevention treatment layers 14a, 14b on both sides, an inner adhesive layer 12b provided on the side of the barrier layer 13 opposite the outer adhesive layer 12a, and a sealant layer 16 provided on the side of the inner adhesive layer 12b opposite the barrier layer 13. Here, the first corrosion prevention treatment layer 14a is provided on the surface of the barrier layer 13 facing the substrate 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 packaging material 10, the base material layer 11 is the outermost layer and the sealant layer 16 is the innermost layer. That is, the 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.

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

[0024] <Base material layer 11> The base material layer 11 serves to impart moldability and insulating properties to the packaging material 10. The base material layer 11 also imparts heat resistance to the sealing process when manufacturing the electricity storage device and serves to suppress the occurrence of pinholes that may occur during molding and distribution. In particular, in the case of packaging materials for large-scale electricity storage devices, the base material layer 11 can also impart scratch resistance, chemical resistance, insulating properties, and the like.

[0025] The base layer 11 has a ratio of the volume resistivity in a 23°C environment to the volume resistivity in a 150°C environment (volume resistivity in a 23°C environment / volume resistivity in a 150°C environment) of 1×10 0 ~1×10 3 The above ratio (resistance change ratio) is 1×10 0 ~5×10 2 Preferably, it is 1×10 0 ~1×10 2When the resistance change ratio is equal to or less than the upper limit, a rapid decrease in the volume resistivity of the base layer 11 due to an increase in temperature can be suppressed, and dielectric breakdown can be suppressed in a high-temperature environment (for example, 150°C).

[0026] The base layer 11 has a volume resistivity of 1×10 13 It is preferable that the resistance is 5×10 Ω·m or more. 13 It is more preferable that it is Ω·m or more, and 1×10 14 The upper limit of the volume resistivity of the base layer 11 in a 23°C environment is not particularly limited, but is, for example, 1×10 16 Ω m or less, 5×10 15 Ω m or less or 1×10 15 When the volume resistivity of the base material layer 11 in an environment of 23°C is equal to or greater than the above lower limit, the occurrence of dielectric breakdown can be more sufficiently suppressed both when used at about 80°C or less and when used in a high-temperature environment (for example, when used at 100 to 150°C).

[0027] The base layer 11 has a volume resistivity of 1×10 12 It is preferable that the resistance is 5×10 Ω·m or more. 12 It is more preferable that it is Ω·m or more, and 1×10 13 The upper limit of the volume resistivity of the base layer 11 in a 150°C environment is not particularly limited, but is, for example, 1×10 15 Ω m or less, 5×10 14 Ω m or less or 1×10 14 When the volume resistivity of the base layer 11 in a 150°C environment is equal to or greater than the above lower limit, the occurrence of dielectric breakdown can be more sufficiently suppressed both when used at about 80°C or less and when used in a high-temperature environment (for example, when used at 100 to 150°C).

[0028] The volume resistivity of the substrate layer 11 can be measured in accordance with JIS K 6911 under conditions of a temperature of 23°C, a relative humidity of less than 20%, or a temperature of 150°C, and a voltage of 100V.

[0029] The base layer 11 is preferably a layer made of a resin film formed from an insulating resin.

[0030] The base layer 11 is preferably a layer made of a semi-aromatic polyamide film, from the viewpoint of satisfying the above-mentioned conditions for the resistance change ratio and volume resistivity and ensuring good moldability.

[0031] 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. Furthermore, the semi-aromatic polyamide can ensure good moldability and also has excellent dimensional stability. By using the semi-aromatic polyamide film as the base layer 11, it is possible to form an exterior material for a power storage device that easily satisfies the above-mentioned requirements for the resistance change ratio and volume resistivity and is resistant to dielectric breakdown even in high-temperature environments (e.g., 150°C).

[0032] The dicarboxylic acid component constituting the semi-aromatic polyamide preferably contains terephthalic acid as a main component. 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%.

[0033] The diamine component constituting the semi-aromatic polyamide preferably contains, as a main component, an aliphatic diamine having 4 to 15 carbon atoms. Examples of aliphatic diamines 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.

[0034] The semi-aromatic polyamide may be copolymerized with lactams such as ε-caprolactam, ζ-enantholactam, η-capryllactam, ω-laurolactam, etc.

[0035] 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 falls within the above range.

[0036] 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 formability can be easily obtained. Examples of stretching methods for biaxially stretched films include sequential biaxial stretching, tubular biaxial stretching, and simultaneous biaxial stretching. Biaxially stretched films are preferably those stretched by simultaneous biaxial stretching or tubular biaxial stretching because better formability can be easily obtained.

[0037] The base layer 11 may be a single layer film made of one type of resin film, or may be a laminated film made of two or more types of resin films.

[0038] The glass transition temperature (Tg) of the substrate layer 11 is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 115°C or higher. When the Tg of the substrate layer 11 is 100°C or higher, the occurrence of dielectric breakdown can be more sufficiently suppressed when used in a high-temperature environment (for example, when used at 100 to 150°C). The upper limit of the Tg of the substrate layer 11 is not particularly limited, but may be, for example, 400°C or lower.

[0039] The thickness of the substrate layer 11 is preferably 5 μm or more, more preferably 6 μm or more, even more preferably 10 μm or more, and particularly preferably 12 μm or more. The thickness of the substrate layer 11 is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 35 μm or less, and particularly preferably 30 μm or less. Having a thickness of the substrate layer 11 of 5 μm or more tends to improve the pinhole resistance and insulating properties of the energy storage device packaging material 10. A thickness of the substrate layer 11 exceeding 50 μm is undesirable because it increases the total thickness of the energy storage device packaging material 10, which may require a reduction in the electrical capacity of the battery. Furthermore, having a thickness of the substrate layer 11 of 50 μm or less can suppress curling after molding of the energy storage device packaging material 10, thereby preventing a decrease in handleability during heat sealing in a subsequent process.

[0040] The base layer 11 has a volume resistivity of 5×10 in a 150° C. environment multiplied by the thickness of the base layer 11. 13 (Ω·m×μm) or more is preferable, and 1×10 14 (Ω·m×μm) or more is more preferable, and 2×10 14 Furthermore, the value obtained by multiplying the volume resistivity of the base layer 11 in a 150°C environment by the thickness of the base layer 11 is 1×10 16(Ω·m×μm) or less, and 5×10 15 If this value is equal to or greater than the above lower limit, the occurrence of dielectric breakdown can be more sufficiently suppressed both when used at about 80°C or less and when used in a high-temperature environment (for example, when used at 100 to 150°C).

[0041] <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 that constitute the outer adhesive layer 12a include polyurethane resins in which a bifunctional or higher isocyanate compound (polyfunctional isocyanate compound) is allowed to react with a base material such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol. Among polyurethane resins, polyester urethane resins that use polyester polyol and bifunctional or higher isocyanate compounds are preferred because they are more likely to prevent a decrease in peel strength in high-temperature environments.

[0042] The various polyols described above can be used alone or in combination of two or more types depending on the functions and performance required of the packaging material.

[0043] Depending on the performance required of the adhesive, various other additives and stabilizers may be blended into the polyurethane resin described above.

[0044] In the polyurethane-based adhesive used to form the outer adhesive layer 12a containing the polyurethane resin described above, the ratio (NCO / OH) of the number of isocyanate 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 material layer 11 and the barrier layer 13 can be further improved in a high-temperature environment (e.g., 150°C), and the base material layer 11 can be more easily prevented from peeling off from the barrier layer 13 in a high-temperature environment. When the ratio is 60 or less, it is possible to prevent excessive unreacted hydroxyl groups from remaining, and the adhesive strength between the base material layer 11 and the barrier layer 13 can be more easily improved in both room temperature and high-temperature environments. The heat resistance of the cured product of the polyurethane-based adhesive (outer adhesive layer 12a) is improved by urea or biuret, which is generated when a trace amount of water contained in the air or the adhesive reacts with the polyfunctional isocyanate compound. Therefore, the more polyfunctional isocyanate compounds there are, the more these units there are, which tends to increase Tg and improve heat resistance.

[0045] 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, conformability, processability, etc. If the thickness of the outer adhesive layer 12a is 1 μm or more, high adhesive strength is likely to be 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 facilitated. On the other hand, if the thickness of the outer adhesive layer is 10 μm or less, the moldability of the packaging material can be further improved.

[0046] <Barrier layer 13> The barrier layer 13 has water vapor barrier properties that prevent moisture from penetrating into the interior of the electricity storage device. The barrier layer 13 may also have extensibility to allow for deep drawing. Examples of the barrier layer 13 that can be used include various metal foils such as aluminum, stainless steel, and copper, as well as metal vapor-deposited films, inorganic oxide vapor-deposited films, carbon-containing inorganic oxide vapor-deposited films, and films having these vapor-deposited films. Examples of films having vapor-deposited films that can be used include aluminum vapor-deposited films and inorganic oxide vapor-deposited films. These may be used alone or in combination of two or more. In terms of mass (specific gravity), moisture resistance, processability, and cost, metal foils are preferred for the barrier layer 13, and aluminum foil is more preferred.

[0047] As the aluminum foil, soft aluminum foil that has been annealed is particularly preferred because it can impart the desired ductility during molding. However, it is more preferable to use aluminum foil containing iron for the purpose of imparting further pinhole resistance and ductility during molding. The iron content in the aluminum foil is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%, based on 100 mass% of the aluminum foil. By having an iron content of 0.1 mass% or more, an exterior packaging material 10 having better pinhole resistance and ductility can be obtained. By having an iron content of 9.0 mass% or less, an exterior packaging material 10 having better flexibility can be obtained. As the aluminum foil, untreated aluminum foil may be used, but it is preferable to use aluminum foil that has been degreased in order to impart corrosion resistance. When the aluminum foil is degreased, the degreasing treatment may be performed on only one side of the aluminum foil, or on both sides.

[0048] The thickness of the barrier layer 13 is not particularly limited, but is preferably 9 to 200 μm, more preferably 15 to 100 μm, in consideration of barrier properties, pinhole resistance, and processability.

[0049] <First and second corrosion prevention treatment layers 14a, 14b> The first and second corrosion prevention treatment layers 14a, 14b are layers provided to prevent corrosion of the metal foil (metal foil layer) that constitutes the barrier layer 13. The first corrosion prevention treatment layer 14a serves to increase the adhesion between the barrier layer 13 and the outer adhesive layer 12a. The second corrosion prevention treatment layer 14b serves to increase the adhesion between the barrier layer 13 and the inner adhesive layer 12b. The first corrosion prevention treatment layer 14a and the second corrosion prevention treatment layer 14b may be layers of the same configuration or layers of different configurations. The first and second corrosion prevention treatment layers 14a, 14b (hereinafter simply referred to as "corrosion prevention treatment layers 14a, 14b") are formed, for example, by degreasing, hydrothermal conversion treatment, anodizing, chemical conversion treatment, or a combination of these treatments.

[0050] Examples of degreasing treatments include acid degreasing and alkaline degreasing. Examples of acid degreasing include a method using an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, or hydrofluoric acid, either alone or in combination. Furthermore, by using an acid degreasing agent prepared by dissolving a fluorine-containing compound such as monosodium ammonium difluoride in the inorganic acid, 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 alkaline degreasing include a method using sodium hydroxide or the like.

[0051] An example of the hydrothermal modification treatment is boehmite treatment, in which aluminum foil is immersed in boiling water containing triethanolamine.

[0052] An example of the anodizing treatment is alumite treatment.

[0053] The chemical conversion treatment may be an immersion type or a 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, an example of the coating type chemical conversion treatment is a method in which a coating agent having corrosion prevention properties is applied to the barrier layer 13.

[0054] When forming at least a part of the corrosion prevention treatment layer by any of these corrosion prevention treatments, i.e., hydrothermal conversion treatment, anodizing treatment, and chemical conversion treatment, it is preferable to perform the above-mentioned degreasing treatment beforehand. Note that when a degreased metal foil, such as a metal foil that has been subjected to an annealing process, is used as the barrier layer 13, there is no need to perform a degreasing treatment again when forming the corrosion prevention treatment layers 14a and 14b.

[0055] The coating agent used in the spray-type chemical conversion treatment preferably contains trivalent chromium and may also contain at least one polymer selected from the group consisting of cationic polymers and anionic polymers, which will be described later.

[0056] Among the above treatments, hydrothermal conversion treatment and anodizing, in particular, dissolve the aluminum foil surface with a treatment agent to form aluminum compounds (boehmite, anodized aluminum) with excellent corrosion resistance. Therefore, a bicontinuous structure is formed from the aluminum foil barrier layer 13 to the corrosion prevention treatment layers 14a, 14b, and these treatments are included in the definition of chemical conversion treatment. On the other hand, as described below, it is also possible to form the corrosion prevention treatment layers 14a, 14b using a pure coating method, which is not included in the definition of chemical conversion treatment. One example of such a method is the use of a sol of a rare earth oxide, such as cerium oxide, with an average particle size of 100 nm or less, which has an aluminum corrosion prevention effect (inhibitor effect) and is environmentally friendly. Using this method, it is possible to impart corrosion prevention effects to metal foils such as aluminum foil using a conventional coating method.

[0057] 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. Of these, water-based sols are preferred.

[0058] In order to stabilize the dispersion of the rare earth element oxide sol, inorganic acids such as nitric acid, hydrochloric acid, phosphoric acid, or their salts, or organic acids such as acetic acid, malic acid, ascorbic acid, and lactic acid are usually used as dispersion stabilizers. Of these dispersion stabilizers, phosphoric acid in particular is expected to have the following effects on the exterior packaging material 10: (1) stabilization of the sol dispersion, (2) improvement of adhesion to the barrier layer 13 by utilizing the aluminum chelating ability of phosphoric acid, and (3) improvement of the cohesion of the corrosion prevention treatment layers 14a, 14b (oxide layers) due to the tendency of phosphoric acid to undergo dehydration condensation even at low temperatures.

[0059] Since the corrosion prevention treatment layers 14a, 14b formed from the rare earth element oxide sol are aggregates of inorganic particles, the cohesive strength of the layers themselves may be reduced even after the dry-cure process. Therefore, in this case, the corrosion prevention treatment layers 14a, 14b are preferably compounded with an anionic polymer or a cationic polymer to compensate for the cohesive strength.

[0060] Furthermore, the corrosion prevention treatment layers 14a, 14b are not limited to the layers described above. For example, they may be formed using a treatment agent that combines phosphoric acid and a chromium compound with a resin binder (such as aminophenol), as in the case of a known paint-type chromate. Using this treatment agent makes it possible to obtain a layer that combines both corrosion prevention functionality and adhesion. Furthermore, although the stability of the coating liquid must be considered, a coating agent that combines a rare earth element oxide sol with a polycationic polymer or a polyanionic polymer in advance as a one-component can be used to obtain a layer that combines corrosion prevention functionality and adhesion.

[0061] The mass per unit area of ​​the corrosion prevention treatment layers 14a and 14b is 0.005 to 0.200 g / m 2 regardless of whether the layer has a multi-layer structure or a single-layer structure. 2is 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 this range, the corrosion prevention function does not change significantly. On the other hand, when a rare earth element 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 treatment layers 14a and 14b can be calculated from their specific gravity.

[0062] 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 salt per 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.

[0063] <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. A general adhesive for bonding a barrier layer and a sealant layer can be used for the inner adhesive layer 12b, and for example, the same adhesive as that for the outer adhesive layer 12a described above can be used.

[0064] The thickness of the inner adhesive layer 12b 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 and processability.

[0065] <Sealant layer 16> The sealant layer 16 is a layer that provides heat-sealing properties to the exterior packaging material 10. Examples of the sealant layer 16 include resin films made of polyolefin resins or polyester resins. These resins (hereinafter also referred to as "base resins") that constitute the sealant layer 16 may be used alone or in combination of two or more.

[0066] Examples of polyolefin resins include low-density, medium-density, or high-density polyethylene; ethylene-α-olefin copolymers; polypropylene; block or random copolymers containing propylene as a copolymerization component; and propylene-α-olefin copolymers.

[0067] Examples of polyester resins include polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, and copolymers thereof.

[0068] The sealant layer 16 may contain a polyolefin-based elastomer. The polyolefin-based elastomer may be compatible or incompatible with the base resin described above, and may contain both a compatible polyolefin-based elastomer that is compatible with the base resin and an incompatible polyolefin-based elastomer that is incompatible with the base resin. "Compatible" means that the elastomer disperses in the base resin with a dispersed phase size of 1 nm or more and less than 500 nm. "Incompatible" means that the elastomer disperses in the base resin with a dispersed phase size of 500 nm or more and less than 20 μm.

[0069] 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.

[0070] The sealant layer 16 may also contain additives such as slip agents, antiblocking agents, antioxidants, light stabilizers, and flame retardants. The content of these additives is preferably 5 parts by mass or less, assuming that the total mass of the sealant layer 16 is 100 parts by mass.

[0071] 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.

[0072] 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.

[0073] The above describes in detail a preferred embodiment of the exterior packaging material for a power storage device of this embodiment, but 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 set forth in the claims.

[0074] For example, Figure 1 shows a case where corrosion prevention treatment layers 14a and 14b are provided on both sides of the barrier layer 13, but only one of the corrosion prevention treatment layers 14a and 14b may be provided, or no corrosion prevention treatment layer may be provided.

[0075] While Fig. 1 shows a case where 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 the packaging material 20 for an electricity storage device shown in Fig. 2. Furthermore, in the packaging material 20 for an electricity storage device shown in Fig. 2, the inner adhesive layer 12b may be provided between the barrier layer 13 and the adhesive resin layer 15.

[0076] <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.

[0077] The modified polyolefin resin is preferably a polyolefin resin graft-modified with an unsaturated carboxylic acid derivative derived from an unsaturated carboxylic acid, or an acid anhydride or ester thereof.

[0078] 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.

[0079] The modified polyolefin resin is preferably a polyolefin resin modified with maleic anhydride. Suitable modified polyolefin resins include, for example, "Admer" manufactured by Mitsui Chemicals, Inc. and "Modic" manufactured by Mitsubishi Chemical Corporation. Such modified polyolefin resins have excellent reactivity with various metals and polymers having various functional groups, and this reactivity can be utilized to impart adhesion to the adhesive resin layer 15. Furthermore, the adhesive resin layer 15 may contain various additives, such as compatible and incompatible elastomers, flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers, as needed.

[0080] The thickness of the adhesive resin layer 15 is not particularly limited, but is preferably the same as or smaller than that of the sealant layer 16 from the viewpoint of stress relaxation and moisture permeation.

[0081] In addition, in the 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.

[0082] [Exterior material manufacturing method] Next, a description will be given of an example of a method for manufacturing the packaging material 10 shown in Fig. 1. Note that the method for manufacturing the packaging material 10 is not limited to the following method.

[0083] The manufacturing method of the exterior material 10 of this embodiment is roughly composed of the steps of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, bonding the base material layer 11 and the barrier layer 13 together using the outer adhesive layer 12a, further laminating the sealant layer 16 via the inner adhesive layer 12b to produce a laminate, and, if necessary, aging the obtained laminate.

[0084] (Step of Laminating Anti-Corrosion Treatment Layers 14a and 14b on Barrier Layer 13) This step is a step of forming corrosion prevention treatment layers 14a and 14b on the barrier layer 13. As described above, examples of the method for forming the corrosion prevention treatment layers 14a and 14b include degreasing treatment, hydrothermal treatment, anodizing treatment, and chemical conversion treatment on the barrier layer 13, and applying a coating agent having corrosion prevention properties.

[0085] Furthermore, when the corrosion prevention treatment layers 14a, 14b are multi-layered, for example, the 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 the 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.

[0086] Degreasing treatment can be performed by spraying or immersion. Hydrothermal conversion treatment and anodizing treatment can be performed by immersion. Chemical conversion treatment can be performed by immersion, spraying, coating, or other methods appropriately selected depending on the type of chemical conversion treatment.

[0087] As a method for applying a coating agent having corrosion prevention properties, various methods such as gravure coating, reverse coating, roll coating, and bar coating can be used.

[0088] As described above, the various treatments may be applied to either one or both sides of the metal foil, but in the case of one-side treatment, the treated side is preferably the side on which the sealant layer 16 is laminated. If desired, the above treatments may also be applied to the surface of the base layer 11.

[0089] 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.

[0090] Furthermore, if dry curing is required, it can be carried out 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.

[0091] (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 and 14b to the base material layer 11 via the outer adhesive layer 12a. As a bonding method, techniques such as dry lamination, non-solvent lamination, and wet lamination are used, and the two are bonded together using the material that constitutes the outer adhesive layer 12a. The outer adhesive layer 12a has a dry coating amount of 1 to 10 g / m 2 range, more preferably 2 to 7 g / m 2 It is set within the range.

[0092] (Laminating step of inner adhesive layer 12b and 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 bonding methods include a wet process and dry lamination.

[0093] In the case of a 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 evaporated at a predetermined temperature to form a dry film, or a baking process is performed as necessary after the dry film formation. The sealant layer 16 is then laminated to produce the exterior material 10. Examples of coating methods 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.

[0094] 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 containing the above-mentioned components of the sealant layer 16. From the viewpoint of productivity, the processing speed of the melt extrusion molding machine can be set to 80 m / min or more.

[0095] (Aging treatment process) This step is a step of subjecting the laminate to an aging (curing) treatment. By subjecting the laminate to an aging treatment, it is possible to promote adhesion between the barrier layer 13, the second corrosion prevention treatment layer 14b, the inner adhesive layer 12b, and the sealant layer 16. The aging treatment can be carried out at a temperature ranging from room temperature to 100°C. The aging time is, for example, 1 to 10 days.

[0096] In this manner, the packaging material 10 of this embodiment as shown in FIG. 1 can be manufactured.

[0097] Next, a description will be given of an example of a method for manufacturing the exterior packaging material 20 shown in Fig. 2. Note that the method for manufacturing the exterior packaging material 20 is not limited to the following method.

[0098] The manufacturing method of the exterior packaging material 20 of this embodiment is generally configured to include the steps of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, bonding the base material layer 11 and the barrier layer 13 together using the outer adhesive layer 12a, further laminating an adhesive resin layer 15 and a sealant layer 16 to prepare a laminate, and, if necessary, heat treating the obtained laminate. Note that the steps up to the step of bonding the base material layer 11 and the barrier layer 13 can be carried out in the same manner as the manufacturing method of the exterior packaging material 10 described above.

[0099] (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. Examples of methods include sand lamination of the adhesive resin layer 15 together with the sealant layer 16 using an extrusion laminator. Furthermore, lamination can also be performed using a tandem lamination method or a co-extrusion method in which the adhesive resin layer 15 and the sealant layer 16 are extruded. When forming the adhesive resin layer 15 and the sealant layer 16, for example, the components are blended so as to satisfy the above-described structures of the adhesive resin layer 15 and the sealant layer 16. The above-described resin composition for forming a sealant layer is used to form the sealant layer 16.

[0100] 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.

[0101] The adhesive resin layer 15 may be formed by directly extruding dry-blended materials having the above-described material composition using an extrusion laminator. Alternatively, the adhesive resin layer 15 may be formed by extruding granules obtained by previously melt-blending the materials using a melt-kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer, and then extruding the granules using an extrusion laminator.

[0102] The sealant layer 16 may be formed by directly extruding materials dry-blended to the composition described above as the constituent components of the resin composition for forming a sealant layer using an extrusion laminator. Alternatively, the adhesive resin layer 15 and the sealant layer 16 may be formed by a tandem lamination method in which the granules obtained by melt-blending the resin composition using a melt-kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer are extruded into the adhesive resin layer 15 and the sealant layer 16 using an extrusion laminator, 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 a sealant layer, and this film may be laminated together with an adhesive resin by sand lamination. The formation 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.

[0103] (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.

[0104] In this manner, the exterior packaging material 20 of this embodiment as shown in FIG. 2 can be manufactured.

[0105] The above describes in detail preferred embodiments of the exterior packaging material for a power storage device of the present disclosure, but 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 set forth in the claims.

[0106] The packaging material for an electricity storage device according to the present disclosure can be suitably used as a packaging material for an electricity storage device such as a secondary battery such as a lithium ion battery, a nickel-metal hydride battery, or a lead-acid battery, and an electrochemical capacitor such as an electric double layer capacitor. In particular, the packaging material for an electricity storage device according to the present disclosure is suitable as a packaging material for an all-solid-state battery using a solid electrolyte.

[0107] [Electricity storage device] FIG. 3 is a perspective view showing one embodiment of an electricity storage device fabricated using the above-described exterior material. As shown in FIG. 3, the electricity storage device 50 includes a battery element (electricity 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 encases 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 encase the battery element 52 by folding one laminate film in half and heat-sealing it, or by overlapping and heat-sealing two laminate films, so that the base material layer 11 is on the exterior side of the electricity storage device 50 and the sealant layer 16 is on the interior side of the electricity storage device 50. Note that the electricity storage device 50 may use an exterior material 20 instead of the exterior material 10.

[0108] Battery element 52 has an electrolyte interposed between a positive electrode and a negative electrode. Metal terminal 53 is a part of the current collector that is taken out from exterior packaging 10, and is made of metal foil such as copper foil or aluminum foil.

[0109] 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. The electricity storage device 50 of this embodiment uses the packaging material 10 of this embodiment, and therefore, even when used in a high-temperature environment (for example, 150°C), it is possible to prevent the insulation properties of the packaging material 10 from decreasing and causing dielectric breakdown. [Example]

[0110] Hereinafter, the present disclosure will be described more specifically based on examples, but the present disclosure is not limited to the following examples.

[0111] [Materials used] The materials used in the examples and comparative examples are shown below.

[0112] <Base material layer> Semi-aromatic polyamide: Semi-aromatic polyamide film produced by the film-forming method shown in Table 1 and having the thickness and Tg shown in the same table. PET: Polyethylene terephthalate film (manufactured by Toray Industries, Inc., product names: Lumirror #25 and #50) produced by the film-forming method shown in Table 1 and having the thickness and Tg shown in the same table. PBT: Polybutylene terephthalate film (manufactured by Kohjin Film & Chemicals Co., Ltd., product name: Boblet) produced by the film-forming method shown in Table 1 and having the thickness and Tg shown in the same table. Nylon 6: Nylon 6 film (manufactured by Unitika Ltd., product name: ON-U) produced by the film-forming method shown in Table 1 and having the thickness and Tg shown in the same table.

[0113] <Outer adhesive layer (thickness: 5 μm)> Polyester urethane: A polyester urethane adhesive was used, which was prepared by blending polyester polyol (manufactured by Toyo-Morton, trade name: TMK-55) and isocyanate (TDI-adduct, manufactured by Toyo-Morton, trade name: CAT-10L) and diluting it with a solvent. PO-based: A polyolefin adhesive prepared by blending Auroren 350S (trade name) manufactured by Nippon Paper Industries Co., Ltd. and DYNAGRAND CR-410B (trade name) manufactured by Toyo-Morton Co., Ltd. and diluting with a solvent was used.

[0114] <First corrosion prevention treatment layer (base layer side) and second corrosion prevention treatment layer (sealant layer side)> (CL-1): "Sodium polyphosphate-stabilized cerium oxide sol" was used, adjusted to a solids concentration of 10% by mass using distilled water as the solvent. The sodium polyphosphate-stabilized cerium oxide sol was obtained by blending 100 parts by mass of cerium oxide with 10 parts by mass of sodium phosphate. (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.

[0115] <Barrier layer (thickness: 40 μm)> Annealed and degreased soft aluminum foil (manufactured by Toyo Aluminum Co., Ltd., "8079 material") was used.

[0116] <Adhesive resin layer (thickness: 27 μm)> As the adhesive resin, a random polypropylene (PP)-based acid-modified polypropylene resin composition (manufactured by Mitsui Chemicals, Inc.) was used.

[0117] <Sealant layer (thickness 53 μm)> A polypropylene-polyethylene random copolymer (manufactured by Prime Polymer Co., Ltd., trade name: F744NP) was used as the resin composition for forming the sealant layer.

[0118] [Fabrication of exterior materials] Example 1 First, first and second corrosion prevention treatment layers were formed on the barrier layer by the following procedure: (CL-1) was applied to both surfaces of the barrier layer in a dry coating amount of 70 mg / m 2 The resulting layer was coated by direct gravure coating so that the coating amount was 20 mg / m, and then baked in a drying unit at 200°C. 2 By applying the coating by direct gravure coating so that the coating was as follows, 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 (CL-1) and (CL-2).

[0119] 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 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 5 μm, drying at 80°C for 30 seconds, laminating it to the base layer, and aging it at 80°C for 120 hours.

[0120] Next, the laminate of the barrier layer and the substrate layer was set on the unwinding section of an extrusion laminator, and an adhesive resin layer (thickness 27 μm) and a sealant layer (thickness 53 μm) were laminated in this order on the second corrosion prevention treatment layer by co-extrusion at 270°C and 80 m / min. Note that the adhesive resin layer and the sealant layer were prepared by compounding various materials in advance using a twin-screw extruder, and then used in the extrusion lamination after undergoing water cooling and pelletizing processes.

[0121] The laminate thus obtained was subjected to a heat treatment so that the maximum temperature of the laminate reached was 190°C, thereby producing an exterior material (a laminate of substrate layer / outer adhesive layer / first corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer / adhesive resin layer / sealant layer).

[0122] (Examples 2 to 3 and Comparative Examples 1 to 5) Exterior materials of Examples 2 and 3 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 / adhesive resin 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 30 seconds and aging at 40°C for 120 hours.

[0123] [Volume resistivity measurement] The volume resistivity of the substrate layers used in the examples and comparative examples was measured in accordance with JIS K 6911 at a temperature of 23°C, a relative humidity of 20% RH or less, or at a temperature of 150°C, and a voltage of 100 V. The resistance change ratio (volume resistivity in a 23°C environment / volume resistivity in a 150°C environment) was also calculated from the volume resistivity in a 23°C environment and the volume resistivity in a 150°C environment. These results are shown in Table 1.

[0124] [Measurement of dielectric breakdown voltage] The exterior packaging materials obtained in the examples and comparative examples were cut into 100 mm x 100 mm pieces to prepare test pieces. The breakdown voltage (AC, 50 Hz) in the direction perpendicular to the surface of the test pieces was measured in accordance with JIS C2110-1. The test conditions were as follows: A measured breakdown voltage of 8 kV or more was rated as "A," a voltage of 7 kV or more but less than 8 kV was rated as "B," and a voltage less than 7 kV was rated as "C." The results are shown in Table 1. (Test conditions) Number of test pieces: 3 Test temperature: 150℃ Surrounding medium: oil Electrode shape: 25mm diameter cylinder / 25mm diameter cylinder Boost method: Short-time test Voltage rise rate: 0.5kV / sec

[0125] [Evaluation of formability] The exterior packaging materials obtained in the Examples and Comparative Examples were cut into rectangular shapes measuring 120 mm in the TD direction and 200 mm in the MD direction and placed in a molding device with the sealant layer facing upward. The molding depth of the molding device was set to 5.0 mm, the holding pressure was set to 0.8 MPa, and cold molding was performed in an environment of room temperature of 23°C and a dew point temperature of -35°C. The punch mold used had a rectangular cross section of 80 mm x 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 used had a die radius (RD) of 1 mm on the top 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 packaging material divided at approximately the center in the longitudinal direction (MD), and the longitudinal direction of the punch mold was aligned with the TD direction of the exterior packaging material.

[0126] Ten samples were produced by deep drawing under the above conditions, and (a) the presence or absence of pinholes and cracks, and (b) the presence or absence of curling after forming were observed and judged based on the following criteria. (a) Presence or absence of pinholes and cracks A: No pinholes or cracks in any of the samples B: 80% to less than 100% of the samples are free of pinholes and cracks C: Less than 80% of the samples are free of pinholes and cracks (b) Presence or absence of curl after molding A: The unformed part does not curl, or even if it curls, the tip of the unformed part does not make a full rotation. C: The tip of the unformed part is curled so that it makes one or more turns. Based on the evaluation results of (a) and (b) above, the moldability of the packaging material was judged according to the following criteria. The results are shown in Table 1. A: The evaluation results for both (a) and (b) above are both rated "A". B: The evaluation result of (a) above is a "B" rating, and the evaluation result of (b) above is an "A" rating. C: At least one of the evaluation results in (a) and (b) above is rated "C"

[0127] [Peel strength measurement] The packaging materials obtained in the examples and comparative examples were cut into test pieces measuring 15 mm in width and 100 mm in length. The peel strength between the substrate layer and the barrier layer of these test pieces was measured in an environment of 150°C. The measurement was carried out by a T-peel test using a tensile tester (manufactured by Shimadzu Corporation) at a pulling rate of 50 mm / min. From the obtained results, the peel strength in an environment of 150°C was evaluated based on the following evaluation criteria. The results are shown in Table 1. A: Peel strength is 1N / 15mm or more C: Peel strength is less than 1N / 15mm

[0128] [Table 1] [Explanation of symbols]

[0129] 10, 20...outer packaging material for electricity storage device, 11...substrate 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 an energy storage device for an all-solid-state battery, having a structure in which at least a base layer, an outer adhesive layer, a barrier layer, and a sealant layer are laminated in this order, The ratio of the volume resistivity of the substrate layer at 23°C to the volume resistivity at 150°C (volume resistivity at 23°C / volume resistivity at 150°C) is 1 × 10⁻¹⁰ ０ ~1 x 10 ３ And, An exterior material for an energy storage device, wherein the base layer is a semi-aromatic polyamide film.

2. The exterior material for an energy storage device according to Claim 1, wherein the volume resistivity of the base layer at a 23°C environment is 1 × 10¹³ Ω·m or more.

3. The exterior material for an energy storage device according to claim 1 or 2, wherein the volume resistivity of the base layer in a 150°C environment is 1 × 10¹² Ω·m or more.

4. The thickness of the substrate layer is 35 μm or less, An exterior material for an energy storage device according to any one of claims 1 to 3, wherein the value obtained by multiplying the volume resistivity of the base material layer at a 150°C environment by the thickness of the base material layer is 5 × 10¹³ (Ω·m × μm) or more.

5. The exterior material for an energy storage device according to Claim 4, wherein the value obtained by multiplying the volume resistivity of the base layer in a 150°C environment by the thickness of the base layer is 5 × 10¹³ to 3 × 10¹⁴ (Ω・m × μm).

6. The exterior material for an energy storage device according to any one of claims 1 to 5, wherein the base material layer is a biaxially stretched film.

7. The exterior material for an energy storage device according to any one of claims 1 to 6, wherein the outer adhesive layer is a layer formed using a polyester urethane adhesive.

8. The exterior material for an energy storage device according to any one of claims 1 to 7, wherein the ratio of the volume resistivity of the base layer at a 23°C environment to the volume resistivity at a 150°C environment (volume resistivity at a 23°C environment / volume resistivity at a 150°C environment) is 1 × 10⁻¹⁰ to 1 × 10⁻².

9. The exterior material for an energy storage device according to any one of claims 1 to 8, wherein the semi-aromatic polyamide constituting the semi-aromatic polyamide film is obtained by copolymerizing a dicarboxylic acid component mainly composed of terephthalic acid with a diamine component.

10. The main body of the energy storage device, Current extraction terminals extending from the main body of the aforementioned energy storage device, An exterior material for a power storage device according to any one of claims 1 to 9, which clamps the current extraction terminal and houses the power storage device body, An energy storage device that is an all-solid-state battery equipped with the following features.

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