Outer package material for electricity storage device and all-solid-state battery provided with same

Abstract

This outer package material for an electricity storage device comprises a base material layer, a metal layer positioned on the base material layer, a sealant layer positioned on the metal layer, and an adhesive layer for bonding the base material layer and the metal layer; and exhibits a thermal diffusivity of 1.4 × 10-7 m2 / s or more.

Description

Exterior material for power storage device and all-solid-state battery including same

[0001] The present disclosure relates to an exterior material for a power storage device and an all-solid-state battery including the same.

[0002] Secondary batteries such as lithium-ion batteries are widely used in portable electronic devices, electric vehicles powered by electricity, hybrid electric vehicles, and the like. Currently used lithium-ion batteries typically include a battery cell (electric storage element) containing a positive electrode, a negative electrode, and a liquid electrolyte (electrolytic solution), and an outer bag that houses the battery cell. The outer bag is formed from the exterior material disclosed in, for example, Patent Document 1. This exterior material includes an emissive layer with an emissivity of 0.6 or higher between an outer film and a metal layer.

[0003] Patent No. 5556128

[0004] Meanwhile, as a next-generation battery of lithium-ion batteries, research and development is being conducted on energy storage devices called all-solid-state batteries. An all-solid-state battery, for example, includes a liquid-free energy storage element and an outer bag that houses the energy storage element. Unlike batteries containing electrolyte, all-solid-state batteries do not volatilize the electrolyte. In addition, the ionic conductivity within a battery generally increases with increasing temperature. Therefore, the internal temperature of all-solid-state batteries during operation tends to be set higher than that of batteries containing electrolyte. The internal temperature rises due to heat generated during operation of the all-solid-state battery.

[0005] Here, when the internal temperature of the all-solid-state battery becomes excessively high or when the internal temperature of the all-solid-state battery is maintained at a high temperature for a long period of time, decomposition of the positive electrode active material contained in the energy storage element may occur. This may cause deterioration of the all-solid-state battery (i.e., deterioration in performance and / or shortening of the life of the all-solid-state battery). Therefore, in order to put the all-solid-state battery into practical use, a mode capable of suppressing the occurrence of the above-mentioned deterioration is desired.

[0006] An object of one aspect of the present disclosure is to provide an exterior packaging material for an electricity storage device that can suppress deterioration caused by heat generated during operation of an electricity storage element, and an all-solid-state battery including the same.

[0007] The packaging material for a power storage device according to one aspect of the present disclosure includes a base material layer, a metal layer located on the base material layer, a sealant layer located on the metal layer, and an adhesive layer that bonds the base material layer and the metal layer together. －７ m ２ / s or more.

[0008] The packaging material for an electricity storage device according to one aspect of the present disclosure has a viscosity of 1.4 × 10 －７ m ２ / s or more. As a result, for example, when an electric storage element housed in the exterior material for an electric storage device generates heat as the electric storage device operates, the heat conducted from the electric storage element to the exterior material for an electric storage device is efficiently dissipated to the outside, such as the outside air. Therefore, by using the exterior material for an electric storage device, it is possible to suppress deterioration caused by heat generated as the electric storage element operates.

[0009] The ratio of the thickness of the metal layer to the thickness of the packaging material for an electricity storage device may be 23% or more and 45% or less. In this case, the packaging material for an electricity storage device can exhibit its functions well while improving its thermal diffusivity, thereby more efficiently dissipating heat through the packaging material for an electricity storage device.

[0010] At least one of the base material layer, the sealant layer, and the adhesive layer may contain a thermally conductive filler, which can improve the thermal diffusivity of at least one of the base material layer, the sealant layer, and the adhesive layer, thereby improving heat dissipation via the packaging material for an electricity storage device.

[0011] The thermally conductive filler may be insulating, in which case the electrical storage device packaging material can exhibit good insulating performance.

[0012] The thermally conductive filler contained in the sealant layer may contain zinc oxide. In this case, the thermal diffusivity of the packaging material for an electricity storage device can be improved while the packaging material for an electricity storage device can adsorb hydrogen sulfide and other contaminants. This can suppress deterioration of the metal layer caused by hydrogen sulfide and other contaminants.

[0013] The sealant layer is a film containing high-density polyethylene or a polypropylene-based resin as a main component, and the packaging material for a power storage device may be a packaging material for an all-solid-state battery. In this case, the packaging material for a power storage device includes a sealant layer that exhibits heat resistance suitable for use in an all-solid-state battery, and therefore is highly suitable as a packaging material for an all-solid-state battery.

[0014] An all-solid-state battery according to one aspect of the present disclosure includes the above-described packaging material for an energy storage device and an energy storage element housed in the packaging material for an energy storage device, and the sealant layer is a film primarily composed of a high-density polyethylene or polypropylene-based resin. In this all-solid-state battery, when heat is generated due to the operation of the energy storage element, the heat conducted from the energy storage element to the packaging material for an energy storage device is efficiently dissipated to the outside air, etc. Therefore, deterioration due to heat generated due to the operation of the energy storage element can be suppressed.

[0015] According to the present disclosure, it is possible to provide an exterior packaging material for an electricity storage device that can suppress deterioration caused by heat generated during operation of an electricity storage element, and an all-solid-state battery including the same.

[0016] Fig. 1 is a schematic cross-sectional view of an exterior packaging material for an electricity storage device according to one embodiment, and Fig. 2 is a perspective view of an electricity storage device according to one embodiment.

[0017] 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.

[0018] [Sheathing material for an electricity storage device] Fig. 1 is a schematic cross-sectional view of an exterior material for an electricity storage device according to one embodiment. As shown in Fig. 1, an exterior material 10 (exterior material for an electricity storage device) according to one embodiment is an exterior material used for an electricity storage device, and includes a base material layer 11, a barrier layer 13 located on the base material layer 11, a sealant layer 15 located on the barrier layer 13, and a first adhesive layer 12a which is an adhesive layer that bonds the base material layer 11 and the barrier layer 13 together, and has a thickness of 1.4 × 10 －７ m ２ / s or more. By using such an exterior material 10, it is possible to suppress deterioration caused by heat generation accompanying the operation of the electricity storage device. From the viewpoint of suppressing deterioration of the electricity storage device, the thermal diffusivity of the exterior material 10 is set to 1.6×10 －７ m ２ / s or more, or 1.75 × 10 －７ m ２ / s or more, or 1.9 × 10 －７ m ２ / s or more. The thermal diffusivity is a quantity that represents the speed at which the temperature distribution relaxes and reaches a thermal equilibrium state. The thermal diffusivity of the exterior packaging material 10 can be obtained, for example, by irradiating the front surface of the exterior packaging material 10 with laser light and analyzing the temperature rise curve of the rear surface of the exterior packaging material 10. The thermal diffusivity of the exterior packaging material 10 can vary depending on the heat dissipation performance of the outermost surface of the exterior packaging material 10, the thermal conductivity performance of the components included in the exterior packaging material 10, and the like.

[0019] The exterior packaging material 10 has a base material layer 11, a first adhesive layer 12a (adhesive layer), a second adhesive layer 12b, a barrier layer 13, and a sealant layer 15. The base material layer 11, the first adhesive layer 12a, the barrier layer 13, the second adhesive layer 12b, and the sealant layer 15 are laminated in this order in the thickness direction of the exterior packaging material 10 (hereinafter simply referred to as the "thickness direction"). When the exterior packaging material 10 is used as an exterior bag for an electricity storage device, the base material layer 11 functions as the outermost layer, and the sealant layer 15 functions as the innermost layer in the exterior packaging material 10.

[0020] <Substrate Layer> The substrate layer 11 is a sheet-like member that functions as the outermost layer of the energy storage device. Therefore, the substrate layer 11 in the packaging material 10 is the portion that dissipates heat from the energy storage device to the outside (e.g., to the outside air, other components in contact with the energy storage device, etc.) when the energy storage device generates heat. Additionally, the substrate layer 11 provides heat resistance during the sealing process in manufacturing the energy storage device and plays a role in suppressing the occurrence of pinholes that may occur during molding, distribution, etc. Particularly in the case of packaging materials for large-scale energy storage devices, the substrate layer 11 may also be provided with scratch resistance, chemical resistance, insulating properties, etc.

[0021] The base layer 11 is a layer formed of, for example, an insulating resin, such as polyester resin, polyamide resin, polyimide resin, polyamideimide resin, polyetherketone resin, polyphenylene sulfide resin, polyetherimide resin, polysulfone resin, fluororesin, phenol resin, melamine resin, urethane resin, allyl resin, silicone resin, epoxy resin, furan resin, or acetyl cellulose resin.

[0022] Among these resins, at least one of polyester resin and polyamide resin may be used as the resin for the base material layer 11 from the viewpoint of moldability. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of polyamide resins include nylon 6, nylon 6,6, copolymers of nylon 6 and nylon 6,6, nylon 9T, nylon 10, polymetaxylylene adipamide (MXD6), nylon 11, and nylon 12. The base material layer 11 may contain additives depending on the desired performance. For example, the base material layer 11 may contain a thermally conductive filler as an additive. This can improve the thermal conductivity of the base material layer 11 and, ultimately, the thermal diffusivity of the exterior packaging material 10. The content of the additive in the base material layer 11 is, for example, 5% by mass or less, 3% by mass or less, or 1% by mass or less. From the viewpoint of the insulating performance of the exterior packaging material 10, the thermally conductive filler may exhibit insulating properties. The thermally conductive filler is, for example, silicon oxide, zinc oxide, aluminum oxide, etc. The thermal conductivity of the thermally conductive filler may be at least three times the thermal conductivity of the resin of the base layer 11 .

[0023] The substrate layer 11 may be in the form of a stretched or unstretched film, or in the form of a coating film. The substrate layer 11 may be a single layer or a multilayer. When the substrate layer 11 is a multilayer, the layers included in the substrate layer 11 may be formed from different resins or from the same resin. When the substrate layer 11 is in the form of a film, the substrate layer 11 may be formed by coextrusion or may be laminated via an adhesive. When the substrate layer 11 is a coating film, the coating film is obtained, for example, by coating a coating film-forming composition multiple times. The substrate layer 11 may have a multilayer structure combining a film and a coating film.

[0024] When the above-mentioned resin is used in the form of a film, the base material layer 11 may be a biaxially stretched film. In this case, the molding property of the packaging material 10 is improved. 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 may be a film stretched by a tubular biaxial stretching method, from the viewpoint of obtaining better deep draw moldability.

[0025] The thickness of the base layer 11 is 10 μm or more and 60 μm or less. The thickness of the base layer 11 may be 15 μm or more, 20 μm or more, 25 μm or more, 50 μm or less, 40 μm or less, or 35 μm or less. When the thickness of the base layer 11 is within the above range, the thermal conductivity of the base layer 11 can be set within a good range.

[0026] The melting point of the base material layer 11 may be higher than the melting point of the sealant layer 15 in order to suppress deformation of the base material layer 11 during sealing. The melting point of the base material layer 11 may be higher than the melting point of the sealant layer 15 by, for example, 30° C. or more.

[0027] The base material layer 11 has a first main surface 11a (exposed surface) which is the outermost surface of the packaging material 10, and a second main surface 11b which is located on the opposite side of the first main surface 11a in the thickness direction and which is in contact with the first adhesive layer 12a. From the viewpoint of heat dissipation of the packaging material 10, the surface roughness of the first main surface 11a is 0.07 μm or more, 0.08 μm or more, or 0.09 μm or more. This increases the area of ​​the base material layer 11 in contact with the outside, which tends to improve heat dissipation through the base material layer 11. The surface roughness of the first main surface 11a is greater than the surface roughness of the smoother side of each main surface of the metal foil 13a. The surface roughness of the first main surface 11a may be greater than the surface roughness of each main surface of the metal foil 13a. From the viewpoint of thermal conductivity within the packaging material 10, the surface roughness of the second main surface 11b may be 0.07 μm or more. This increases the contact area of ​​the first adhesive layer 12a with the base material layer 11, which tends to improve heat conduction from the first adhesive layer 12a to the base material layer 11. Note that the surface roughness according to one embodiment is the three-dimensional arithmetic mean height Sa defined in ISO 25178, and corresponds to a parameter obtained by expanding the arithmetic mean height Ra of a line to a surface.

[0028] <First Adhesive Layer> The first 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 first adhesive layer 12a include polyurethane resins in which a bifunctional or higher isocyanate compound (a polyfunctional isocyanate compound) acts as a curing agent on a base material such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol. 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 exterior packaging material 10. In addition to the above, materials that constitute the first adhesive layer 12a can also be used, such as those that contain an epoxy resin as a base material and a curing agent.

[0029] The first adhesive layer 12a is formed using an adhesive composition (first adhesive composition) containing the above-described base agent and curing agent. Furthermore, the first adhesive layer 12a may contain various other additives, stabilizers, etc., depending on the performance required of the adhesive layer. Examples of additives include a tin-based, titanium-based, or zirconium-based urethane catalyst to accelerate curing, and a tangible curing agent or a latent curing agent. Examples of tangible curing agents or latent curing agents include amine-based compounds. These may be used alone or in combination. A thermally conductive filler may also be used as an additive. This can improve the thermal conductivity of the first adhesive layer 12a and the thermal diffusivity of the exterior packaging material 10. From the perspective of the insulating performance of the exterior packaging material 10, the thermally conductive filler may exhibit insulating properties. The thermal conductivity of the thermally conductive filler needs to be at least three times that of the base agent. The content of the additive in the first adhesive layer 12a is, for example, 15% by mass or less, 13% by mass or less, or 10% by mass or less.

[0030] The first adhesive composition may contain, as a curing agent, at least one polyfunctional isocyanate compound selected from the group consisting of alicyclic isocyanate polymers and isocyanate polymers containing an aromatic ring in the molecular structure. Examples of polyfunctional isocyanate compounds include nurate forms of isophorone diisocyanate, adduct forms of tolylene diisocyanate, adduct forms of hexamethylene diisocyanate, biuret forms and nurate forms of hexamethylene diisocyanate, biuret forms and nurate forms of tolylene diisocyanate, adduct forms, biuret forms and nurate forms of diphenylmethane diisocyanate, and adduct forms, biuret forms and nurate forms of xylylene diisocyanate.

[0031] As the curing agent, an alicyclic isocyanate polymer and an isocyanate polymer containing an aromatic ring in the molecular structure may be used in combination. By using these in combination, heat resistance tends to be further improved.

[0032] From the viewpoint of heat resistance, the first adhesive composition may contain at least one polyol selected from the group consisting of polyester polyol, acrylic polyol, and polycarbonate diol. From the viewpoint of heat resistance, the first adhesive composition may contain polyester polyol among these.

[0033] The thickness of the first adhesive layer 12a is not particularly limited, but is, for example, 1 μm or more and 10 μm or less, or 2 μm or more and 7 μm or less, from the viewpoint of obtaining the desired adhesive strength, thermal conductivity, conformability, processability, etc.

[0034] <Barrier Layer> The barrier layer 13 is a member having water vapor barrier properties that prevent moisture from penetrating into the interior of the power storage device. The barrier layer 13 may also have ductility for deep drawing. In one embodiment, the barrier layer 13 is a metal layer in which first and second corrosion prevention treatment layers 14a, 14b are provided on a metal foil 13a. In the barrier layer 13, the thickness of the metal foil 13a is significantly greater than the thickness of the first and second corrosion prevention treatment layers 14a, 14b. In one embodiment, the thickness of the barrier layer 13 is considered to be equal to the thickness of the metal foil 13a.

[0035] The metal foil 13a may be, for example, an aluminum foil, a stainless steel foil, a copper foil, or any other metal foil. From the viewpoints of mass (specific gravity), barrier properties such as moisture resistance, processability, and cost, the metal foil 13a may be an aluminum foil or a stainless steel foil. When the metal foil 13a is an aluminum foil, the metal foil 13a may be a soft aluminum foil that has been annealed, since it can provide the desired extensibility during molding. To provide further pinhole resistance and extensibility during molding, the metal foil 13a may be an aluminum foil containing iron. The iron content in the aluminum foil is preferably 0.1% by mass or more and 9.0% by mass or less, and more preferably 0.5% by mass or more and 2.0% by mass or less, based on 100% by mass of the aluminum foil. By having an iron content of 0.1% by mass or more, an exterior packaging material 10 having better pinhole resistance and extensibility can be obtained. By having an iron content of 9.0% by 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.

[0036] The metal foil 13a has a first main surface 13b covered with a first corrosion prevention treatment layer 14a and a second main surface 13c covered with a second corrosion prevention treatment layer 14b. For example, one of the first main surface 13b and the second main surface 13c is a glossy surface, and the other of the first main surface 13b and the second main surface 13c is a matte surface. The glossy surface is the surface that comes into contact with the rollers of the rolling mill during the production of the metal foil 13a. The matte surface is the surface that does not come into contact with the rolling mill during the production of the metal foil 13a and has more irregularities than the glossy surface. Therefore, the glossy surface is smoother than the matte surface. In this embodiment, the first main surface 13b is a matte surface and the second main surface 13c is a glossy surface, but this is not limited to this. From the viewpoint of the heat dissipation properties of the exterior packaging material 10, the surface roughness of the glossy layer is, for example, 0.07 μm or more. This increases the contact area of ​​the metal foil 13a with other members, which tends to improve heat conduction to other members via the metal foil 13a. The surface roughness of the matte surface needs to be greater than the surface roughness of the glossy surface.

[0037] The thickness of the barrier layer 13 is not particularly limited, but may be 9 μm or more and 200 μm or less, 15 μm or more and 100 μm or less, or 40 μm or more and 80 μm or less, from the viewpoints of barrier properties, pinhole resistance, processability, etc. From the viewpoint of the thermal diffusivity of the packaging material 10, the ratio of the thickness of the barrier layer 13 to the thickness of the packaging material 10 may be 15% or more, 20% or more, 23% or more, 26% or more, or 30% or more. Furthermore, from the viewpoint of the insulating properties of the packaging material 10, the ratio of the thickness of the barrier layer 13 to the thickness of the packaging material 10 may be 50% or less, 45% or less, 43% or less, or 40% or less. In one embodiment, the ratio of the thickness of the barrier layer 13 to the thickness of the packaging material 10 may be 15% or more and 50% or less, 23% or more and 45% or less, or 26% or more and 45% or less.

[0038] <First and Second Anti-Corrosion Treatment Layers> The first and second anti-corrosion treatment layers 14a, 14b are layers provided to prevent corrosion of the metal foil 13a. The first anti-corrosion treatment layer 14a may have the function of increasing the adhesion between the barrier layer 13 and the first adhesive layer 12a. Similarly, the second anti-corrosion treatment layer 14b may have the function of increasing the adhesion between the barrier layer 13 and the second adhesive layer 12b. The first anti-corrosion treatment layer 14a and the second anti-corrosion treatment layer 14b may be layers of the same configuration or layers of different configurations. The first and second anti-corrosion treatment layers 14a, 14b may be formed by, for example, degreasing treatment, hydrothermal conversion treatment, anodizing treatment, chemical conversion treatment, or a combination of these treatments.

[0039] 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, in acid degreasing, it is preferable to use an acid degreasing agent prepared by dissolving a fluorine-containing compound such as monosodium ammonium difluoride in the inorganic acid. In this case, particularly when the metal foil 13a is an aluminum foil, the degreasing effect of aluminum can be obtained. Furthermore, acid degreasing agents can form aluminum fluorides, which are passive, and are effective in terms of corrosion resistance. Examples of alkaline degreasing include a method using sodium hydroxide or the like.

[0040] An example of the hydrothermal modification treatment is boehmite treatment, in which aluminum foil is immersed in boiling water containing triethanolamine. An example of the anodization treatment is alumite treatment.

[0041] The chemical conversion treatment may be an immersion type or a coating type. Examples of the immersion type chemical conversion treatment include a chromate treatment, a zirconium treatment, a titanium treatment, a vanadium treatment, a molybdenum treatment, a calcium phosphate treatment, a strontium hydroxide treatment, a cerium treatment, a ruthenium treatment, or 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 metal foil 13a.

[0042] 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, or chemical conversion treatment, it is preferable to perform the degreasing treatment described above in advance. Note that when a degreased metal foil, such as a metal foil that has been subjected to an annealing process, is used as the metal foil 13a, there is no need to perform a degreasing treatment again when forming the first and second corrosion prevention treatment layers 14a, 14b.

[0043] 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.

[0044] Furthermore, among the above treatments, hydrothermal conversion treatment and anodizing treatment, 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 metal foil 13a to the first and second corrosion prevention treatment layers 14a, 14b, and therefore the above treatments are included in the definition of chemical conversion treatment. On the other hand, as described below, it is also possible to form the first and second corrosion prevention treatment layers 14a, 14b using a pure coating method, which is not included in the definition of chemical conversion treatment. Examples of such methods include a method using 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 common coating method.

[0045] 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. In one embodiment, a water-based sol may be used.

[0046] 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 (1) to (4) in the 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; (3) imparting corrosion resistance by capturing aluminum ions (passivation formation); and (4) improvement of the cohesion of the corrosion prevention treatment layer due to the tendency of phosphoric acid to undergo dehydration condensation even at low temperatures.

[0047] Since the first and second 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 curing process. Therefore, in this case, the first and second corrosion prevention treatment layers 14a, 14b may be compounded with an anionic polymer or a cationic polymer to compensate for the cohesive strength.

[0048] The first and second corrosion prevention treatment layers 14a, 14b are not limited to the layers described above. For example, they may be formed using a treatment agent containing a resin binder (such as aminophenol) mixed with phosphoric acid and a chromium compound, as in the case of a known paint-type chromate. Using this treatment agent can provide a layer that combines both corrosion prevention and adhesion. Furthermore, although the stability of the coating liquid must be considered, a coating agent prepared by preliminarily preparing a one-component mixture of a rare earth element oxide sol and a polycationic or polyanionic polymer can also be used to provide a layer that combines corrosion prevention and adhesion.

[0049] The mass per unit area of ​​the first and second corrosion prevention treatment layers 14a, 14b is 0.005 g / m2 regardless of whether the layer has a multi-layer structure or a single-layer structure. ２ 0.200g / m or more ２ Preferably, the content is 0.010 g / m or less. ２ 0.100g / m or more ２ It is more preferable that the mass per unit area is 0.005 g / m or less. 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 μm, the corrosion prevention function does not change significantly. On the other hand, when a rare earth element oxide sol is used, if the coating film is thick, the heat curing during drying may be insufficient, which may result in a decrease in cohesive force. The thicknesses of the first and second corrosion prevention treatment layers 14 a, 14 b can be calculated from their specific gravities.

[0050] From the viewpoint of making it easier to maintain adhesion between the sealant layer 15 and the barrier layer 13, the first and second corrosion prevention treatment layers 14a, 14b may be in an embodiment containing, for example, cerium oxide, 1 part by mass or more and 100 parts by mass or less of phosphoric acid or a phosphate salt per 100 parts by mass of the cerium oxide, and a cationic polymer, or may be in an embodiment formed by subjecting the barrier layer 13 to a chemical conversion treatment, or may be in an embodiment formed by subjecting the barrier layer 13 to a chemical conversion treatment and containing a cationic polymer.

[0051] <Second Adhesive Layer> The second adhesive layer 12b is a layer that bonds the barrier layer 13 and the sealant layer 15. The second adhesive layer 12b is formed from an adhesive composition (second adhesive composition) containing at least the following resin. The resin is not particularly limited as long as it is a resin that can be used as an adhesive, but it may include, for example, a modified polyolefin. In this case, the second adhesive layer 12b exhibits high adhesion to the barrier layer 13 and the sealant layer 15, thereby improving the laminate strength of the exterior packaging material 10. Examples of modified polyolefins include hydroxyl-modified polyolefins, glycidyl-modified polyolefins, and acid-modified polyolefins. From the viewpoint of adhesion to the barrier layer 13 and the sealant layer 15, the second adhesive composition may contain an acid-modified polyolefin as the resin. The acid-modified polyolefin is a polyolefin graft-modified with an unsaturated carboxylic acid derivative derived from an unsaturated carboxylic acid, an unsaturated sulfonic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like.

[0052] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic acid. Examples of acid anhydrides of unsaturated carboxylic acids include acid anhydrides of unsaturated carboxylic acids such as maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic acid anhydride. Examples of esters of unsaturated carboxylic acids include esters of unsaturated carboxylic acids such as methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconic acid, dimethyl tetrahydrophthalic anhydride, and dimethyl bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylate.

[0053] Examples of polyolefins include polyethylene-based resins such as low-density polyethylene (LDPE or LLDPE), medium-density polyethylene (MDPE), high-density polyethylene, and ethylene-α-olefin copolymers; and polypropylene-based resins such as homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymers. From the viewpoint of heat resistance, the polyolefin may be a polypropylene-based resin.

[0054] The acid-modified polyolefin may be a polyolefin modified with maleic anhydride, from the viewpoint of obtaining excellent adhesion between the barrier layer 13 and the second adhesive layer 12b. When the sealant layer-forming resin composition that forms the sealant layer 15 contains a polyolefin, the polyolefin may be the same as the polyolefin contained in the second adhesive layer 12b. For example, when the sealant layer-forming resin composition contains a polypropylene-based resin as a resin, the second adhesive layer 12b may contain an acid-modified polypropylene-based resin. In this case, the second adhesive layer 12b can have high adhesion to the sealant layer 15 and can also improve the heat resistance of the exterior packaging material 10.

[0055] When the resin contained in the second adhesive layer 12b includes a modified polyolefin, the second adhesive composition may further include a polyfunctional isocyanate compound as a curing agent. In this case, the second adhesive layer 12b can have excellent adhesion and heat resistance. Examples of polyfunctional isocyanate compounds include diisocyanates such as tolylene diisocyanate, xylylene diisocyanate or its hydrogenated product, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate or its hydrogenated product, and isophorone diisocyanate; polyisocyanates such as adducts obtained by reacting these isocyanates with polyhydric alcohols such as trimethylolpropane, biuret products obtained by reacting these isocyanates with water, and trimer isocyanurates (isocyanurate-type polyfunctional isocyanate compounds); and blocked polyisocyanates obtained by blocking these polyisocyanates with alcohols, lactams, oximes, or the like. The polyfunctional isocyanate compound may contain an isocyanurate (isocyanurate-type polyfunctional isocyanate compound). In this case, the second adhesive layer 12b can have excellent adhesion and heat resistance, and the packaging material 10 can have high seal strength and heat resistance. When the second adhesive layer 12b contains a modified polyolefin and a polyfunctional isocyanate compound, the amount of the polyfunctional isocyanate compound may be, for example, 3 parts by mass or less per 100 parts by mass of the modified polyolefin (solid content).

[0056] The second adhesive composition may further contain various additives, such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, a dehydrating agent, and a crystal nucleating agent, as needed. A thermally conductive filler may also be used as an additive. This can improve the thermal conductivity of the second adhesive layer 12b and the thermal diffusivity of the exterior packaging material 10. From the perspective of the insulating performance of the exterior packaging material 10, the thermally conductive filler may exhibit insulating properties. Note that the thermal conductivity of the thermally conductive filler only needs to be at least three times that of the resin. The second adhesive composition may also contain zinc oxide as a thermally conductive filler. In this case, hydrogen sulfide generated in the power storage device can be adsorbed within the second adhesive layer 12b. This can suppress corrosion of the metal foil 13a due to hydrogen sulfide. The content of the additive in the second adhesive layer 12b is, for example, 15% by mass or less, 13% by mass or less, or 10% by mass or less.

[0057] The second adhesive composition may be, for example, a polyurethane adhesive containing a polyester polyol made of a hydrogenated dimer fatty acid and a diol, a polyisocyanate, and a hydrophobic insulating inorganic filler. From the viewpoint of heat resistance, examples of the second adhesive layer-forming composition include a base material such as a polyester polyol, a polyether polyol, an acrylic polyol, or a carbonate polyol, a polyurethane resin reacted with a bifunctional or higher isocyanate compound, and an epoxy resin reacted with an amine compound or the like on a base material having an epoxy group.

[0058] The thickness of the second adhesive layer 12b is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, thermal conductivity, processability, etc., it is, for example, 0.2 μm or more and 30 μm or less, 1 μm or more and 20 μm or less, or 2 μm or more and 15 μm or less.

[0059] <Sealant Layer> The sealant layer 15 is a layer that provides heat-sealing properties to the exterior packaging material 10 and is disposed on the inside and heat-sealed (thermally fused) during assembly of the energy storage device. From the viewpoints of heat resistance, thermal conductivity, and the like, the base resin (main component) of the sealant layer 15 is, for example, a polyolefin such as high-density polyethylene (HDPE) or polypropylene, or a polyester. The high-density polyethylene is, for example, a crystalline linear polyethylene. The density (specific gravity) of the high-density polyethylene is, for example, 0.94 or 0.942 or more. Examples of polyesters include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), and copolymers thereof.

[0060] In one embodiment, the main component of the sealant layer 15 includes a polypropylene-based resin. The polypropylene-based resin is a resin obtained from a polymerized monomer containing propylene. Examples of the polypropylene-based resin include homopolypropylene, block polypropylene, and random polypropylene. These may be used alone or in combination of two or more. From the viewpoint of the heat resistance and flexibility of the sealant layer 15, the polypropylene-based resin may include at least one of homopolypropylene and block polypropylene. The content of the polypropylene-based resin in the sealant layer 15 is not particularly limited and is, for example, 30% by mass or more and 100% by mass or less.

[0061] In addition to the main component, the sealant layer 15 may contain an additive resin containing a polyethylene-based resin or a block copolymer compatible with polypropylene-based resins. Polyethylene-based resins are resins obtained from polymerized monomers containing ethylene and serve to impart softness (stress relaxation properties). Examples of polyethylene-based resins include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene, and polyethylene-based elastomers. These may be used alone or in combination of two or more. Since polyethylene-based resins can particularly impart softness, it is preferable for them to contain a polyethylene-based elastomer. The block copolymer compatible with polypropylene-based resins is sufficient as long as it is compatible with at least polypropylene-based resins, and may be, for example, one of the compatibilizers described below.

[0062] The polyethylene elastomer may be an elastomer containing an α-olefin as a comonomer, such as a compound obtained by copolymerizing ethylene with at least one α-olefin selected from 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene.

[0063] When the sealant layer 15 contains a polyethylene-based resin as an additive resin, the content of the polyethylene-based resin in the sealant layer 15 is not particularly limited and is, for example, 1% by mass or more and 70% by mass or less. When the sealant layer 15 contains a block copolymer that is compatible with the polypropylene-based resin, the content of the block copolymer in the sealant layer 15 is not particularly limited and is, for example, 1% by mass or more and 70% by mass or less.

[0064] The sealant layer 15 may contain other additive components, such as slip agents, antiblocking agents, antioxidants, light stabilizers, crystal nucleating agents, and flame retardants, as needed. Furthermore, the sealant layer 15 may contain a thermally conductive filler as another additive component. From the viewpoint of the insulating performance of the exterior packaging material 10, the thermally conductive filler may exhibit insulating properties. Zinc oxide may be included as the thermally conductive filler. In this case, hydrogen sulfide generated in the electricity storage device can be adsorbed within the sealant layer 15. This makes it possible to suppress corrosion of the metal foil 13a due to hydrogen sulfide. The content of these additive components is, for example, 15% by mass or less, 13% by mass or less, or 10% by mass or less, when the total mass of the sealant layer 15 is 100% by mass.

[0065] The thickness of the sealant layer 15 is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, thermal conductivity, processability, etc., it is, for example, 30 μm or more and 200 μm or less, 50 μm or more and 180 μm or less, or 80 μm or more and 160 μm or less.

[0066] 2 is a perspective view showing an electricity storage device according to an embodiment of the present disclosure. As shown in Fig. 2, an all-solid-state battery 50 serving as an electricity storage device includes an electricity storage element 52, two metal terminals (current extraction terminals) 53 for extracting current from the electricity storage element 52 to the outside, and an outer bag 54 for hermetically housing the electricity storage element 52.

[0067] The outer bag 54 is formed using the exterior material 10 to have a bag main body 54a and a seal portion 54b provided on the bag main body 54a, and is used as a container for accommodating the energy storage element 52. In the exterior material 10, the base material layer 11 is the outermost layer, and the sealant layer 15 is the innermost layer. For example, the exterior bag 54 is formed by folding one exterior material 10 in half and heat-sealing the peripheral portions so that the base material layer 11 is on the outside of the all-solid-state battery 50 and the sealant layer 15 is on the inside of the all-solid-state battery 50. Alternatively, the exterior bag 54 is formed by stacking two exterior materials 10 and heat-sealing the peripheral portions.

[0068] The metal terminal 53 is sandwiched by an exterior bag 54 with the sealant layer 15 on the inside. The metal terminal 53 may be sandwiched by the exterior bag 54 via a tab sealant. The metal terminal 53 is a part of the current collector that is taken out to the outside of the exterior material 10, and is made of a metal foil such as copper foil or aluminum foil.

[0069] The energy storage element 52 has a pair of electrodes and a solid electrolyte sandwiched between the pair of electrodes. One of the pair of electrodes is a positive electrode and the other is a negative electrode. Examples of the solid electrolyte include a sulfide-based solid electrolyte and an oxide-based solid electrolyte.

[0070] The exterior packaging material 10 according to the embodiment described above has a thickness of 1.4 × 10 －７ m ２ The exterior material 10 exhibits a thermal diffusivity of 1 / s or more. Therefore, when the energy storage element 52 housed in the exterior material 10 generates heat due to the operation of the energy storage device, the heat conducted from the energy storage element 52 to the exterior material 10 is efficiently dissipated to the outside without using, for example, a heat sink or a cooling fan. This makes it difficult for the energy storage element 52 to store heat, making it difficult for the internal temperature of the energy storage element 52 to become excessively high. Additionally, the internal temperature of the energy storage element 52 is unlikely to be maintained after the energy storage element 52 is in operation. Therefore, the use of the exterior material 10 can suppress deterioration due to heat generated during operation of the energy storage element 52. Furthermore, since a cooling fan or the like for the energy storage device is not required, costs and the device can be reduced, and power consumption due to the cooling fan or the like can be prevented.

[0071] In one embodiment, due to the layer structure of the exterior packaging material 10, the maximum value of the thermal diffusivity of the exterior packaging material 10 is, for example, 5.0 × 10 －７ m ２ / s to 6.0 x 10 －７ m ２ / s. Therefore, by using the exterior material 10, the internal temperature of the energy storage element 52 can be maintained at a temperature appropriate for the operation of the all-solid-state battery 50 (for example, approximately 80°C to 120°C) during operation of the energy storage element 52. Here, the sealant layer 15 may be a film containing high-density polyethylene or a polypropylene-based resin as a main component. In this case, the exterior material 10 includes a sealant layer 15 that exhibits heat resistance appropriate for use with the all-solid-state battery 50. Therefore, by using the exterior material 10, the ionic conductivity and the like within the energy storage element 52 during operation can be set within a favorable range, thereby improving the performance of the energy storage device.

[0072] In one embodiment, the ratio of the thickness of the barrier layer 13, which is a metal layer, to the thickness of the exterior packaging material 10 may be 23% or more and 45% or less. In this case, the thermal diffusivity of the exterior packaging material 10 can be improved while maintaining the functionality of the exterior packaging material 10, thereby improving heat dissipation through the exterior packaging material 10.

[0073] In one embodiment, at least one of the base layer 11, the sealant layer 15, the first adhesive layer 12a, and the second adhesive layer 12b may contain a thermally conductive filler. In this case, the thermal diffusivity of at least one of the base layer 11, the sealant layer 15, the first adhesive layer 12a, and the second adhesive layer 12b can be improved, thereby improving heat dissipation through the packaging material 10. Furthermore, at least one of the second adhesive layer 12b and the sealant layer 15 may contain zinc oxide as a thermally conductive filler. In this case, hydrogen sulfide and other substances generated during operation of the energy storage device can be adsorbed by the packaging material 10. Here, the inclusion of zinc oxide in at least one of the second adhesive layer 12b and the sealant layer 15 makes it difficult for hydrogen sulfide and other substances to reach the metal foil 13a. This makes it possible to suppress deterioration of the metal foil 13a caused by hydrogen sulfide and other substances.

[0074] In one embodiment, the surface roughness of the first main surface 11a of the base material layer 11 and the surface roughness of the shiny surface of the metal foil 13a are each 0.07 μm or greater, with the surface roughness of the first main surface 11a being greater than the surface roughness of the shiny surface. This improves heat conduction (heat dissipation) to the outside air via the first main surface 11a of the base material layer 11, and heat conduction to the base material layer 11 via the metal foil 13a or heat conduction from the sealant layer 15 via the metal foil 13a. In particular, because the surface roughness of the first main surface 11a is greater than the surface roughness of the shiny surface, heat dissipation from the packaging material 10 to the outside air is improved. Therefore, heat storage in the packaging material 10 is effectively suppressed, while heat dissipation via the packaging material 10 is more effectively achieved.

[0075] The packaging material for a power storage device and the all-solid-state battery including the same according to one aspect of the present disclosure are as described in the following [1] to [7], and have been described in detail based on the above-mentioned embodiment and the above-mentioned modified example. [1] A packaging material for a power storage device and an all-solid-state battery including the same are provided, the packaging material for a power storage device and the all-solid-state battery including the same are as described in the following [1] to [7]. The ... above-mentioned embodiment and the above-mentioned modified example. [1] A packaging material for a power storage device and an all-solid-state battery including the same are provided, the packaging material for a power storage device and the all-solid-state battery including the same are as described in the following [1] to [7]. The packaging material for a power storage device and the all-solid-state battery including the same are as described in the above-mentioned －７ m ２ / s or more. [2] The packaging material for an electricity storage device according to [1], wherein a ratio of the thickness of the metal layer to a thickness of the packaging material for an electricity storage device is 23% or more and 45% or less. [3] The packaging material for an electricity storage device according to [1] or [2], wherein at least one of the base layer, the sealant layer, and the adhesive layer contains a thermally conductive filler. [4] The packaging material for an electricity storage device according to [3], wherein the thermally conductive filler exhibits insulating properties. [5] The packaging material for an electricity storage device according to [3] or [4], wherein the thermally conductive filler contained in the sealant layer contains zinc oxide. [6] The packaging material for an electricity storage device according to any of [1] to [5], wherein the sealant layer is a film containing high-density polyethylene or a polypropylene-based resin as a main component, and wherein the packaging material is an all-solid-state battery packaging material. [7] An all-solid-state battery comprising the packaging material for an electricity storage device according to any of [1] to [6], and an electricity storage element accommodated in the packaging material for an electricity storage device.

[0076] However, one aspect of the present disclosure is not limited to the above embodiment and the above [1] to [7]. One aspect of the present disclosure can be further modified within the scope of the gist thereof.

[0077] The exterior packaging material for a power storage device according to the present disclosure can also be used as an exterior packaging material for power storage devices such as secondary batteries, such as lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries, and electrochemical capacitors, such as electric double layer capacitors. However, the exterior packaging material for a power storage device according to the present disclosure can be particularly suitably used as an exterior packaging material for a power storage device made of an all-solid-state battery.

[0078] Hereinafter, the present disclosure will be described more specifically based on examples, but the present disclosure is not limited to the following examples.

[0079] [Materials Used] The materials used in at least one of the following examples and comparative examples are shown below.

[0080] <Substrate Layer> Any of the following (D1) to (D7) was used as the substrate layer. (D1): polyethylene terephthalate (PET) film (manufactured by Unitika Ltd., thickness: 25 μm) (D2): laminate of polyethylene terephthalate (PET) film (manufactured by Unitika Ltd., thickness: 6 μm) and nylon (Ny) film (manufactured by Toyobo Co., Ltd., thickness: 15 μm) (D3): laminate of two polyethylene terephthalate (PET) films (manufactured by Unitika Ltd., thickness: 25 μm) laminated via an adhesive layer (made of the first adhesive composition described below, thickness: 4 μm) (D4): laminate of two polyethylene terephthalate films (manufactured by Unitika Ltd., thickness: 50 μm) laminated via an adhesive layer (made of the first adhesive composition described below, thickness: 4 μm) (D5): polybutylene terephthalate (PBT) film (manufactured by Kohjin Film & Chemicals Co., Ltd., thickness: 25 μm) (D6): A laminate of a polyethylene terephthalate (PET) film (manufactured by Unitika Ltd., thickness: 15 μm) and a polybutylene terephthalate (PBT) film (manufactured by Kohjin Film & Chemicals Co., Ltd., thickness: 15 μm) laminated via an adhesive layer (made of the first adhesive composition described below, thickness: 4 μm). (D7): A laminate of two polybutylene terephthalate (PBT) films (manufactured by Kohjin Film & Chemicals Co., Ltd., thickness: 15 μm) laminated via an adhesive layer (made of the first adhesive composition described below, thickness: 4 μm).

[0081] <First adhesive composition> As the first adhesive composition, a polyurethane adhesive (manufactured by Toyo Ink Co., Ltd.) containing a polyester polyol-based base agent and a tolylene diisocyanate adduct-based curing agent was prepared.

[0082] <Metal Layer> A soft aluminum foil (manufactured by Toyo Aluminum K.K., "8079 material") was used as the metal foil. Either a 40 μm-thick metal foil or an 80 μm-thick metal foil was used. Anti-corrosion treatment was performed on both sides of each metal foil. The following (CL-1) and (CL-2) were prepared as materials used in the anti-corrosion treatment of the metal foil. The sodium polyphosphate-stabilized cerium oxide sol was produced by blending 100 parts by mass of cerium oxide with 10 parts by mass of sodium salt of phosphoric acid. (CL-1): "Sodium polyphosphate-stabilized cerium oxide sol" obtained by using distilled water as a solvent and adjusting the solid content to 10% by mass. (CL-2): A composition consisting of 90% by mass of "polyallylamine (manufactured by Nitto Boseki Co., Ltd.)" and 10% by mass of "polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation)" obtained by using distilled water as a solvent and adjusting the solid content to 5% by mass.

[0083] <Second adhesive composition> As the second adhesive composition, a composition containing an acid-modified polyolefin resin ("200S" manufactured by Nippon Paper Industries Co., Ltd.) as a main component and an isocyanurate-based two-component material ("TPA-100" under Duranate (registered trademark) manufactured by Asahi Kasei Corporation) as a curing agent was used.

[0084] <Resin composition for forming sealant layer> Using a twin-screw extruder, a resin composition for forming a sealant layer containing any one of the following (S1) to (S3) as a main component was used: (S1) High-density polyethylene (HDPE, manufactured by Japan Polypropylene Corporation, Novatec (registered trademark) HD, "HF560") (S2) Polypropylene (manufactured by SunAllomer Co., Ltd., "PC684S") (S3) Polyethylene terephthalate (manufactured by Unitika Ltd., Sealant PET)

[0085] <Thermal Conductive Filler> Powder of zinc oxide (manufactured by Hakusui Tech Co., Ltd.) was used as the thermally conductive filler.

[0086] Example 1 [Preparation of Exterior Material] First, a barrier layer was formed by providing a first and second corrosion prevention treatment layer on a metal foil having a thickness of 40 μm. Specifically, (CL-1) was applied to both surfaces of the metal foil in a dry coating amount of 70 mg / m. ２ The resulting layer was coated by microgravure coating so that the dry coating amount was 20 mg / m. ２ The coating was performed by microgravure coating so that the coating was as follows: As a result, composite layers consisting of (CL-1) and (CL-2) were 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).

[0087] Next, the first corrosion prevention treatment layer of the barrier layer and (D1), which is a substrate layer, were bonded by dry lamination using the first adhesive composition. This formed a first laminate consisting of the substrate layer, the first adhesive layer, and the barrier layer. Specifically, the first adhesive composition was applied onto the first corrosion prevention treatment layer of the barrier layer, and then a drying process was performed at 80°C for 1 minute to form the first adhesive layer. The first adhesive composition was applied so that the thickness of the first adhesive layer after curing would be 4 μm. Subsequently, (D1) was bonded to the first adhesive layer. Then, the barrier layer and the substrate layer were laminated via the first adhesive layer by aging at 80°C for 120 hours. This formed a first laminate.

[0088] Next, the first laminate was set on the unwinding section of an extrusion laminator. Subsequently, a second adhesive composition was applied onto the second corrosion prevention treatment layer, followed by a drying process at 100°C for 1 minute to form a second adhesive layer. The second adhesive composition was applied so that the thickness of the second adhesive layer after curing would be 3 μm. Subsequently, an 80 μm-thick sealant layer was attached to the second adhesive layer. Then, the resulting exterior material was formed by aging at 40°C for 120 hours. The above-mentioned sealant layer was formed by extruding a resin composition for forming a sealant layer, mainly composed of (S1), at 270°C and 80 m / min. In Example 1, the ratio of the thickness of the metal foil to the thickness of the exterior material is shown in Table 1 below.

[0089] (Example 2) Except for changing the thickness of the metal foil to 80 μm, an exterior material was formed in the same manner as in Example 1. In Example 2, the ratio of the thickness of the metal foil to the thickness of the exterior material is shown in Table 1 below.

[0090] (Example 3) Except for using (D3) as the base material layer, an exterior packaging material was formed in the same manner as in Example 1. In Example 3, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0091] (Example 4) Except for changing the thickness of the sealant layer to 100 μm, an exterior packaging material was formed in the same manner as in Example 1. In Example 4, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0092] (Example 5) Except for using (D2) as the base material layer, an exterior packaging material was formed in the same manner as in Example 1. In Example 5, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0093] (Example 6) An exterior packaging material was formed in the same manner as in Example 1, except that the thickness of the sealant layer was set to 160 μm and the sealant layer contained a thermally conductive filler. In Example 6, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0094] (Example 7) An exterior material was formed in the same manner as in Example 6, except that a thermally conductive filler was contained in the first adhesive layer. In Example 7, the ratio of the thickness of the metal foil to the thickness of the exterior material is shown in Table 1 below.

[0095] (Example 8) Except for using (D5) as the base material layer, an exterior packaging material was formed in the same manner as in Example 1. In Example 8, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0096] (Example 9) Except for using (D6) as the base material layer, an exterior packaging material was formed in the same manner as in Example 1. In Example 9, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0097] (Example 10) Except for using (D7) as the base material layer, an exterior packaging material was formed in the same manner as in Example 1. In Example 10, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0098] (Comparative Example 1) Except for using (D4) as the base material layer, an exterior packaging material was formed in the same manner as in Example 1. In Comparative Example 1, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0099] (Comparative Example 2) Except for changing the thickness of the sealant layer to 160 μm, an exterior packaging material was formed in the same manner as in Example 1. In Comparative Example 2, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 1 below.

[0100] (Example 11) Except for using (S2) as the main component of the sealant layer, an exterior packaging material was formed in the same manner as in Example 1. In Example 11, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 2 below.

[0101] (Example 12) An exterior packaging material was formed in the same manner as in Example 8, except that the base material layer was (D3). In Example 12, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 2 below.

[0102] (Example 13) Except for using (S3) as the main component of the sealant layer, an exterior packaging material was formed in the same manner as in Example 1. In Example 13, the ratio of the thickness of the metal foil to the thickness of the exterior packaging material is shown in Table 2 below.

[0103] <Thermal diffusivity> First, the packaging material of Example 1 was cut to form a 5 mm square sample. The thermal diffusivity of the sample was then measured at room temperature of 23°C in a windless environment using a thermal diffusivity measuring device (iPhase Mobile 1U, manufactured by iPhase Corporation). The thermal diffusivity of the sample is the thermal diffusivity of the packaging material of Example 1, and is shown in Table 1 below. The thermal diffusivities of the packaging materials of Examples 2 to 13 and Comparative Examples 1 and 2 were also measured in the same manner as in Example 1. The thermal diffusivities of Examples 2 to 10 and Comparative Examples 1 and 2 are shown in Table 1 below. The thermal diffusivities of Examples 11 to 13 are shown in Table 2 below.

[0104] <Heat Dissipation Performance> First, the packaging material of Example 1 was heated to 100°C in an oven, then removed from the oven and left to stand in a room at room temperature of 23°C until the temperature of the packaging material reached 23°C. At this time, the time from when the packaging material was removed from the oven until the temperature of the packaging material reached 23°C was measured. In addition, the same time was measured for each of the packaging materials of Examples 2 to 13 and Comparative Examples 1 and 2 as in Example 1. The heat dissipation performance of each Example and Comparative Example was evaluated based on the following evaluation criteria. The evaluation results of Examples 1 to 10 and Comparative Examples 1 and 2 are shown in Table 1 below. The evaluation results of Examples 11 to 13 are shown in Table 2 below.

[0105] [Evaluation criteria] A: Measurement time is 80 seconds or less B: Measurement time is more than 80 seconds

[0106]

[0107]

[0108] REFERENCE SIGNS LIST 10...outer packaging material (outer packaging material for electricity storage device), 11...substrate layer, 11a...first main surface (exposed surface), 11b...second main surface, 12a...first adhesive layer, 12b...second adhesive layer (adhesive layer), 13...barrier layer, 13a...metal foil, 13b...first main surface, 13c...second main surface, 14a...first corrosion prevention treatment layer, 14b...second corrosion prevention treatment layer, 15...sealant layer, 50...all-solid-state battery (electricity storage device), 52...electricity storage element, 54...outer packaging bag, 54a...bag main body, 54b...sealing portion.

Claims

1. A substrate layer, a metal layer located on the substrate layer, a sealant layer located on the metal layer, and an adhesive layer that bonds the substrate layer and the metal layer, －７ m ２ 1. An exterior material for an electrical storage device, which exhibits a thermal diffusivity of 100 / s or more.

2. The packaging material for a storage battery device according to claim 1, wherein the ratio of the thickness of the metal layer to the thickness of the packaging material for a storage battery device is 23% or more and 45% or less.

3. The packaging material for a storage battery device according to claim 1 or 2, wherein at least one of the base material layer, the sealant layer, and the adhesive layer contains a thermally conductive filler.

4. The packaging material for a power storage device according to claim 3, wherein the thermally conductive filler exhibits insulating properties.

5. The packaging material for a power storage device according to claim 3, wherein the thermally conductive filler contained in the sealant layer includes zinc oxide.

6. The packaging material for a storage battery according to claim 1 or 2, wherein the sealant layer is a film mainly composed of high density polyethylene or polypropylene resin, and is a packaging material for an all-solid-state battery.

7. An all-solid-state battery comprising: the packaging material for a storage battery device according to claim 6; and a storage element housed in the packaging material for a storage battery device.

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