Exterior material for power storage device, power storage device, and power storage apparatus

Abstract

An exterior material for a power storage device according to the present disclosure comprises: a hydrogen sulfide adsorption layer containing a hydrogen sulfide adsorbent; a base material layer; a metal foil layer; and a sealant layer, in this order. In the exterior material for a power storage device, the hydrogen sulfide adsorbent is composed of metal oxide, and the hydrogen sulfide adsorbent content in the hydrogen sulfide adsorption layer is not less than 0.5 mass%.

Description

Exterior material for power storage device, power storage device, and power storage equipment

[0001] The present disclosure relates to an exterior material for an electricity storage device, an electricity storage device, and an electricity storage apparatus.

[0002] In an electricity storage device such as an all-solid-state battery, an electricity storage element having a sulfide-based solid electrolyte is housed in an exterior bag formed using an exterior material.

[0003] Sulfide-based solid electrolytes react with moisture in the air to generate toxic hydrogen sulfide, and measures to prevent this are necessary. For example, efforts have been made to improve the moisture barrier properties of packaging materials to prevent moisture from the air from penetrating into the inside of the packaging bag. For example, Patent Document 1 below discloses a laminate sheet for sulfide-based all-solid-state batteries, which is an example of a packaging material for forming such packaging bags, and which has, in this order, a base layer, a barrier layer, a moisture absorption layer containing a moisture absorbent, and a sulfide-based gas absorption layer containing a hydrogen sulfide absorbent.

[0004] Japanese Patent Application Laid-Open No. 2020-187855

[0005] However, the laminate sheet for a sulfide-based all-solid-state battery described in Patent Document 1 has room for improvement in terms of adsorption of hydrogen sulfide.

[0006] The present disclosure has been made in view of the above circumstances, and has an object to provide an exterior material for an electricity storage device, an electricity storage device, and an electricity storage apparatus that can effectively adsorb hydrogen sulfide.

[0007] One aspect of the present disclosure provides an exterior packaging material for an electricity storage device, comprising: a hydrogen sulfide adsorption layer containing a hydrogen sulfide adsorbent; a substrate layer; a metal foil layer; and a sealant layer, in this order; wherein the hydrogen sulfide adsorbent is made of a metal oxide; and the content of the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer is 0.5 mass% or more.

[0008] The above-described configuration of the packaging material for an electricity storage device (hereinafter also simply referred to as "packaging material") allows the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer to effectively adsorb hydrogen sulfide when hydrogen sulfide permeates the packaging material. Therefore, this packaging material can prevent hydrogen sulfide generated in an outer packaging bag formed using the packaging material from leaking to the outside of the packaging material. Furthermore, because the hydrogen sulfide adsorption layer is located on the opposite side of the sealant layer from the metal foil layer, even if water is generated as a result of the adsorption reaction of hydrogen sulfide by the hydrogen sulfide adsorbent, the water (hereinafter also referred to as "moisture") is unlikely to permeate the metal foil layer. Therefore, moisture is unlikely to penetrate into the packaging bag formed using the packaging material. Therefore, even if a solid electrolyte is disposed in the packaging bag, generation of hydrogen sulfide due to a reaction between moisture and the solid electrolyte can be prevented.

[0009] In the electrical storage device packaging material, the base material layer preferably contains a hydrogen sulfide adsorbent, and the hydrogen sulfide adsorbent is preferably made of a metal oxide. In this case, the hydrogen sulfide adsorbent is contained not only in the hydrogen sulfide adsorption layer but also in the base material layer, so that when hydrogen sulfide permeates the packaging material, it is adsorbed not only by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer but also by the hydrogen sulfide adsorbent in the base material layer. Therefore, the electrical storage device packaging material can more effectively adsorb hydrogen sulfide.

[0010] In the packaging material for a power storage device, the content of the hydrogen sulfide adsorbent in the base layer is preferably 0.5 mass % or more. In this case, hydrogen sulfide is effectively adsorbed by the hydrogen sulfide adsorbent in the base layer, and therefore hydrogen sulfide is effectively adsorbed by the packaging material.

[0011] In the above-described packaging material for a power storage device, at least one of the hydrogen sulfide adsorption layer and the base layer preferably further contains a color developer that changes color upon reaction with hydrogen sulfide, the color developer preferably being a metal salt of an acid. In this case, when an excessive amount of hydrogen sulfide permeates the packaging material, the color developer in the layer containing the color developer, either the hydrogen sulfide adsorption layer or the base layer, begins to discolor upon reaction with hydrogen sulfide. The discoloration of the color developer indicates that the hydrogen sulfide adsorbent can no longer adsorb hydrogen sulfide and that the packaging material can no longer be used. This makes it easier to determine whether the packaging material can be continued.

[0012] In the packaging material for a power storage device, the total content of the hydrogen sulfide adsorbent and the color developer in the hydrogen sulfide adsorption layer or the base material layer is preferably 30% by mass or less, which makes the hydrogen sulfide adsorption layer or the base material layer less likely to become brittle.

[0013] In the packaging material for a power storage device, the metal oxide preferably includes an oxide of a divalent metal, which allows for more effective adsorption of hydrogen sulfide.

[0014] In the electrical storage device packaging material, the hydrogen sulfide adsorption layer is preferably obtained using a coating liquid containing the hydrogen sulfide adsorbent. In this case, the hydrogen sulfide adsorption layer can be easily formed regardless of the type of hydrogen sulfide adsorbent contained in the coating liquid.

[0015] In the electrical storage device packaging material, the coating liquid preferably further contains a binder resin, and the binder resin preferably contains at least one of an acrylic resin and a urethane resin. In this case, when the coating liquid contains the binder resin, the hydrogen sulfide adsorbent is fixed in the hydrogen sulfide adsorption layer, making it less likely to fall off. Furthermore, when the binder resin contains at least one of a urethane resin and an acrylic resin, the chemical resistance of the hydrogen sulfide adsorption layer can be improved, and the chemical resistance of the packaging material can be improved.

[0016] In the packaging material for a power storage device, the sealant layer preferably contains a resin but does not contain a hydrogen sulfide adsorbent. In this case, gaps are prevented from forming between the resin and the hydrogen sulfide adsorbent contained in the sealant layer due to poor compatibility between them, improving moisture barrier properties. Furthermore, because the sealant layer does not contain a hydrogen sulfide adsorbent, which is a foreign substance to the resin, heat seal strength can be increased.

[0017] The packaging material for an energy storage device preferably further includes an adhesive layer between the base material layer and the metal foil layer, in which case the adhesive layer improves adhesion between the base material layer and the metal foil layer, thereby suppressing delamination in the packaging material.

[0018] Another aspect of the present disclosure provides an electricity storage device including an outer bag and an electricity storage element housed in the outer bag, wherein the outer bag is obtained using the electricity storage device exterior material, the hydrogen sulfide adsorption layer of the electricity storage device exterior material is the outermost layer, and the electricity storage element contains an electrolyte.

[0019] According to the above-described electricity storage device, even if hydrogen sulfide is generated inside the outer bag, the hydrogen sulfide can be effectively adsorbed by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer as the hydrogen sulfide permeates through the outer bag. Therefore, this electricity storage device can prevent hydrogen sulfide generated inside the outer bag from leaking to the outside of the outer bag. Furthermore, because the hydrogen sulfide adsorption layer is located on the opposite side of the sealant layer from the metal foil layer, even if water is generated as a result of the adsorption reaction of hydrogen sulfide by the hydrogen sulfide adsorbent, the water does not easily permeate the metal foil layer, making it difficult for the water to enter the outer bag. This prevents the electrolyte in the electricity storage element housed inside the outer bag from coming into contact with water, thereby preventing the generation of hydrogen sulfide due to the reaction between water and the electrolyte.

[0020] The electricity storage device is particularly useful when the electrolyte is a solid electrolyte (i.e., an all-solid-state battery). When the electricity storage device is an all-solid-state battery, the electricity storage element may react with moisture to generate hydrogen sulfide inside the outer bag, but even in this case, the hydrogen sulfide is effectively adsorbed by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer as it passes through the outer bag, thereby preventing hydrogen sulfide from leaking outside the outer bag.

[0021] Yet another aspect of the present disclosure provides a power storage apparatus including a plurality of power storage devices and a housing that houses the plurality of power storage devices, wherein the power storage devices are the power storage devices described above.

[0022] By virtue of the above configuration, even if hydrogen sulfide is generated in each of the electricity storage devices, the hydrogen sulfide can be effectively adsorbed by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer as the hydrogen sulfide permeates the exterior bag. Therefore, this electricity storage device can prevent hydrogen sulfide generated in each of the electricity storage devices from leaking from inside the electricity storage device into the space between the housing and the electricity storage device. Furthermore, in this electricity storage device, the hydrogen sulfide adsorption layer is located on the opposite side of the metal foil layer from the sealant layer in the exterior bag of the electricity storage device. Therefore, even if a malfunction of one of the electricity storage devices causes hydrogen sulfide to leak from the exterior bag of that electricity storage device into the space between the electricity storage device and the housing, the hydrogen sulfide can be effectively adsorbed by the hydrogen sulfide adsorption layers of the exterior bags of the other electricity storage devices, preventing hydrogen sulfide from leaking outside the housing.

[0023] According to the present disclosure, there are provided an exterior packaging material for an electricity storage device, an electricity storage device, and an electricity storage device that can effectively adsorb hydrogen sulfide.

[0024] Fig. 1 is a cross-sectional view schematically showing an embodiment of an exterior material for an electricity storage device according to the present disclosure. Fig. 2 is a perspective view schematically showing an embodiment of an electricity storage device according to the present disclosure. Fig. 3 is a cross-sectional view schematically showing an embodiment of an electricity storage device according to the present disclosure.

[0025] 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.

[0026] [Sheathing Material for Electricity Storage Device] Fig. 1 is a cross-sectional view schematically illustrating an exterior material for an electricity storage device according to an embodiment of the present disclosure. As shown in Fig. 1, exterior material 10 of this embodiment is an exterior material used in an electricity storage device, and includes, in this order, a hydrogen sulfide adsorption layer 17, a substrate layer 11, a metal foil layer 13, and a sealant layer 16. The hydrogen sulfide adsorbent (hereinafter also simply referred to as "adsorbent") in hydrogen sulfide adsorption layer 17 is 0.5 mass% or more. Furthermore, as shown in Fig. 1, exterior material 10 may include a first adhesive layer 12 between substrate layer 11 and metal foil layer 13, and a second adhesive layer 15 between metal foil layer 13 and sealant layer 16.

[0027] When hydrogen sulfide permeates the packaging material 10, the hydrogen sulfide can be effectively adsorbed by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer 17. Therefore, the packaging material 10 can prevent hydrogen sulfide generated in an outer packaging bag formed using the packaging material 10 from leaking to the outside of the packaging material 10. Furthermore, because the hydrogen sulfide adsorption layer 17 is located on the opposite side of the sealant layer 16 from the metal foil layer 13, even if water is generated as a result of the adsorption reaction of hydrogen sulfide by the hydrogen sulfide adsorbent, the water does not easily permeate the metal foil layer 13, and therefore water is unlikely to enter the outer packaging bag formed using the packaging material 10. This prevents the electrolyte in the electricity storage element housed in the outer packaging bag from coming into contact with water, thereby preventing the generation of hydrogen sulfide due to the reaction between water and the electrolyte.

[0028] The metal foil layer 13 may have a first corrosion prevention treatment layer 14a on the substrate layer 11 side, and may have a second corrosion prevention treatment layer 14b on the sealant layer 16 side. When the packaging material 10 is used as an outer bag for an electricity storage device, the hydrogen sulfide adsorption layer 17 is the outermost layer and the sealant layer 16 is the innermost layer in the packaging material 10. That is, the packaging material 10 is used with the hydrogen sulfide adsorption layer 17 facing the outside of the electricity storage device and the sealant layer 16 facing the inside of the electricity storage device.

[0029] Each layer constituting the exterior packaging material 10 will be specifically described below.

[0030] <Hydrogen sulfide adsorption layer> The hydrogen sulfide adsorption layer 17 is a layer that adsorbs hydrogen sulfide and contains a hydrogen sulfide adsorbent. The hydrogen sulfide adsorption layer 17 is obtained using a resin composition for forming a hydrogen sulfide adsorption layer that contains a hydrogen sulfide adsorbent.

[0031] The hydrogen sulfide adsorbent is made of a metal oxide that adsorbs hydrogen sulfide. Examples of metal oxides include oxides of monovalent metals such as silver oxide, oxides of divalent metals such as zinc oxide, calcium oxide, copper oxide, lead oxide, manganese oxide, nickel oxide, cobalt oxide, tin oxide, and cadmium oxide, oxides of trivalent metals, and oxides of tetravalent metals. Among these, the hydrogen sulfide adsorbent is preferably an oxide of a divalent metal. In this case, hydrogen sulfide can be more effectively adsorbed. The divalent metal oxide is particularly preferably zinc oxide. In this case, hydrogen sulfide can be even more effectively adsorbed.

[0032] The hydrogen sulfide adsorbent may be a non-conductive hydrogen sulfide adsorbent as described above, or may be a conductive hydrogen sulfide adsorbent, such as conductive zinc oxide.

[0033] The content of the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer 17 may be 0.5% by mass or more, and may be 1% by mass or more, 5% by mass or more, 10% by mass or more, or 15% by mass or more. When the content is 0.5% by mass or more, hydrogen sulfide is effectively adsorbed by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer 17, and thus hydrogen sulfide is effectively adsorbed by the exterior packaging material 10. The content may be 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, or 5% by mass or less. In this case, the hydrogen sulfide adsorption layer 17 is less likely to become brittle. The content may be, for example, 0.5% by mass or more to 30% by mass or less, 0.5% by mass or more to 20% by mass or less, 1% by mass or more to 10% by mass or less, or 1% by mass or more to 5% by mass or less.

[0034] The hydrogen sulfide adsorption layer 17 may or may not further contain a color developer that changes color upon reaction with hydrogen sulfide. If the hydrogen sulfide adsorption layer 17 contains a color developer, when an excessive amount of hydrogen sulfide permeates the packaging material 10, the color developer in the hydrogen sulfide adsorption layer 17 begins to discolor due to reaction with hydrogen sulfide. The discoloration of the color developer is an indication that the hydrogen sulfide adsorbent can no longer adsorb hydrogen sulfide and the packaging material 10 cannot be continued. This makes it easier to determine whether the packaging material 10 can be continued. Furthermore, if the hydrogen sulfide adsorption layer 17 contains a color developer, it is easy to visually confirm that the color developer has reacted with hydrogen sulfide and discolored in an packaging bag obtained using the packaging material 10 and with the hydrogen sulfide adsorption layer 17 as the outermost layer.

[0035] The color developer is a material that changes color upon reaction with hydrogen sulfide and is composed of a metal salt of an acid. The acid may be an organic acid or an inorganic acid. Examples of organic acids include acetic acid, and examples of inorganic acids include sulfuric acid. Examples of metals include monovalent metals such as silver, and divalent metals such as lead and copper. Examples of metal salts of acids include lead acetate, silver sulfate, and copper sulfate. These can be used alone or in combination of two or more.

[0036] The content of the color developer in the hydrogen sulfide adsorption layer 17 may be 0.01% by mass or more, 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, or 5% by mass or more. When the content is 0.01% by mass or more, if the color developer reacts with hydrogen sulfide and discolors, the discoloration of the hydrogen sulfide adsorption layer 17 becomes more pronounced, thereby making it possible to more reliably determine whether the color developer has reacted with hydrogen sulfide. The content may be 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, or 5% by mass or less. In this case, the hydrogen sulfide adsorption layer 17 is less likely to become brittle. The content may be, for example, 0.01% by mass or more to 30% by mass or less, 0.01% by mass or more to 20% by mass or less, 0.5% by mass or more to 10% by mass or less, or 1% by mass or more to 5% by mass or less.

[0037] The total content of the hydrogen sulfide adsorbent and the color developer in the hydrogen sulfide adsorption layer 17 may be 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less. In particular, the total content is preferably 30% by mass or less. In this case, the hydrogen sulfide adsorption layer 17 is less likely to become brittle. Furthermore, when the hydrogen sulfide adsorption layer 17 contains a resin, a decrease in the proportion of the resin further suppresses a decrease in the role and function inherent to the resin. The total content may be 0.5% by mass or more. The total content may be 1% by mass or more, 3% by mass or more, or 5% by mass or more. A total content of 1% by mass or more enables effective adsorption of hydrogen sulfide.

[0038] The resin composition for forming the hydrogen sulfide adsorption layer 17 may contain a catalyst that enhances the reactivity of the components in the resin composition for forming the hydrogen sulfide adsorption layer, or may further contain a catalyst and a reaction retarder. Examples of the catalyst include a urethanization catalyst, and examples of the reaction retarder include acetylacetone.

[0039] The hydrogen sulfide adsorption layer 17 may further contain various additives, such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, a dehydrating agent, a crystal nucleating agent, and a tackifier, as needed.

[0040] The hydrogen sulfide adsorption layer 17 may be in the form of a coating film, or in the form of a stretched or unstretched film.

[0041] When the hydrogen sulfide-adsorbing layer 17 is a coating film, the hydrogen sulfide-adsorbing layer 17 is obtained by using a coating liquid containing a hydrogen sulfide adsorbent as a resin composition for forming the hydrogen sulfide-adsorbing layer. In this case, the hydrogen sulfide-adsorbing layer 17 can be easily formed regardless of the type or amount of the hydrogen sulfide adsorbent contained in the coating liquid or the thickness of the hydrogen sulfide-adsorbing layer 17. The hydrogen sulfide-adsorbing layer 17 can be formed by coating the coating liquid containing the hydrogen sulfide adsorbent once or for the number of times the hydrogen sulfide-adsorbing layer 17 is to be laminated.

[0042] The coating liquid containing the hydrogen sulfide adsorbent may further contain a binder resin. By including the binder resin in the coating liquid, the hydrogen sulfide adsorbent is fixed in the hydrogen sulfide adsorbing layer 17, making it less likely to fall off. The binder resin is not particularly limited, and examples of the binder resin include acrylic resin, urethane resin, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, polyetherketone resin, polyphenylene sulfide resin, polyetherimide resin, polysulfone resin, fluororesin, phenolic resin, melamine resin, allyl resin, silicone resin, epoxy resin, furan resin, and acetyl cellulose resin. The binder resin preferably contains at least one of an acrylic resin and a urethane resin. By including at least one of a urethane (urethane resin) and an acrylic resin in the binder resin, the chemical resistance of the hydrogen sulfide adsorbing layer 17 can be improved, thereby improving the chemical resistance of the exterior packaging material 10.

[0043] When the hydrogen sulfide-adsorbing layer 17 is a stretched or unstretched film, the resin composition for forming the hydrogen sulfide-adsorbing layer contains a hydrogen sulfide adsorbent and a binder resin. Examples of the binder resin include acrylic resin, urethane resin, polyester resin, polyamide resin, polyimide resin, polyamide-imide resin, polyether ketone resin, polyphenylene sulfide resin, polyetherimide resin, polysulfone resin, fluororesin, phenol resin, melamine resin, allyl resin, silicone resin, epoxy resin, furan resin, and acetyl cellulose resin. From the viewpoint of improving the chemical resistance of the hydrogen sulfide-adsorbing layer 17, the binder resin preferably contains at least one of urethane (urethane resin) and acrylic resin.

[0044] The thickness of the hydrogen sulfide adsorption layer 17 is not particularly limited, but is preferably 1 to 20 μm, and more preferably 2 to 5 μm. When the thickness of the hydrogen sulfide adsorption layer 17 is 1 μm or more, the hydrogen sulfide adsorption layer 17 can hold a sufficient amount of hydrogen sulfide adsorbent, and therefore hydrogen sulfide is more effectively adsorbed when hydrogen sulfide permeates the hydrogen sulfide adsorption layer 17. When the thickness of the hydrogen sulfide adsorption layer 17 is 20 μm or less, the total thickness of the packaging material 10 can be reduced.

[0045] <Substrate Layer> The substrate layer 11 provides heat resistance in a sealing step when manufacturing the electricity storage device and plays a role in suppressing the occurrence of pinholes that may occur during molding, processing, distribution, etc. In particular, when the packaging material is an packaging material for a large-scale electricity storage device, the substrate layer 11 can also be provided with scratch resistance, chemical resistance, insulating properties, etc.

[0046] The base layer 11 is preferably a layer formed of 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.

[0047] 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, and in the case of a multilayer, a combination of different resins may be used. When the substrate layer 11 is a film, a substrate layer obtained by co-extrusion of multiple layers, or a substrate layer obtained by laminating multiple layers via an adhesive, may be used. When the substrate layer 11 is a coating film, a substrate layer 11 coated with the same number of layers may be used. The substrate layer 11 may also be a multilayer formed by combining a film and a coating film.

[0048] Among these resins, polyester resins and polyamide resins are preferred for the base layer 11 because of their excellent 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, nylons such as nylon 10, nylon 11, and nylon 12, and aromatic polyamides such as nylon 9T and polymetaxylylene adipamide (MXD6).

[0049] When these resins are used in the form of a film, the base layer 11 is preferably a biaxially stretched film. Examples of the stretching method when the base layer 11 is a biaxially stretched film include sequential biaxial stretching, tubular biaxial stretching, and simultaneous biaxial stretching. From the viewpoint of obtaining better deep drawability, the biaxially stretched film is preferably a film stretched by tubular biaxial stretching.

[0050] The substrate layer 11 may or may not contain a hydrogen sulfide adsorbent, but preferably contains one. In this case, the hydrogen sulfide adsorbent is contained not only in the hydrogen sulfide adsorbing layer 17 but also in the substrate layer 11. Therefore, when hydrogen sulfide permeates the packaging material 10, it is adsorbed not only by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorbing layer 17 but also by the hydrogen sulfide adsorbent in the substrate layer 11. When the substrate layer 11 is multilayered, one layer of the substrate layer 11 may contain a hydrogen sulfide adsorbent, or multiple layers or all layers may contain a hydrogen sulfide adsorbent.

[0051] The content of the hydrogen sulfide adsorbent in the substrate layer 11 is not particularly limited and may be less than 0.5% by mass or greater than 0.5% by mass, but is preferably greater than 0.5% by mass. In this case, hydrogen sulfide is effectively adsorbed by the hydrogen sulfide adsorbent in the substrate layer 11. The content may be greater than 1% by mass, or greater than 2% by mass. The content may be 30% by mass or less, 20% by mass or less, 15% by mass or less, or 10% by mass or less. When the content is 30% by mass or less, the substrate layer 11 is less likely to become brittle. The content may be, for example, 0.5% by mass or more and 30% by mass or less, 0.5% by mass or more and 20% by mass or less, 15% by mass or more and 10% by mass or less, or 1% by mass or more and 5% by mass or less.

[0052] The substrate layer 11 may contain a color developer that changes color upon reaction with hydrogen sulfide. The color developer is made of a metal salt of an acid. In this case, when an excessive amount of hydrogen sulfide permeates the packaging material 10, the color developer in the substrate layer 11 begins to discolor due to reaction with hydrogen sulfide. The discoloration of the color developer indicates that the hydrogen sulfide adsorbent can no longer adsorb hydrogen sulfide and that the packaging material 10 cannot be continued. This makes it easier to determine whether the packaging material 10 can be continued to be used. When both the hydrogen sulfide adsorption layer 17 and the substrate layer 11 contain color developers, the color developers may be the same or different.

[0053] When the base layer 11 contains a color developer, the base layer 11 may or may not contain a hydrogen sulfide adsorbent. Here, the hydrogen sulfide adsorbent may be the same as the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer 17. The hydrogen sulfide adsorbent in the base layer 11 may be the same as or different from the hydrogen sulfide adsorbent in the hydrogen sulfide adsorbent layer 17.

[0054] The content of the color developer in the base material layer 11 may be 0.01% by mass or more, 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, or 2% by mass or more. When the content is 0.01% by mass or more, discoloration of the base material layer 11 becomes more noticeable when the color developer reacts with hydrogen sulfide and discolors, making it easier to determine whether the packaging material 10 can be continued to be used. The content may be 30% by mass or less, 20% by mass or less, 5% by mass or less, or 1% by mass or less. When the content is 30% by mass or less, the base material layer 11 is less likely to become brittle. The content may be, for example, 0.01% by mass or more and 30% by mass or less, 0.01% by mass or more and 20% by mass or less, 0.5% by mass or more and 10% by mass or less, or 1% by mass or more and 5% by mass or less.

[0055] The total content of the hydrogen sulfide adsorbent and the color developer in the base layer 11 is preferably 30% by mass or less. In this case, the base layer 11 is less likely to become brittle. Furthermore, when the base layer 11 contains a resin, a decrease in the resin proportion further prevents the resin from deteriorating in its original role and function. The content may be 20% by mass or less, 15% by mass or less, or 10% by mass or less. The content may be 0.01% by mass or more, 0.5% by mass or more, 1% by mass or more, or 2% by mass or more. The content may be, for example, 0.01% by mass or more to 20% by mass or less, 0.01% by mass or more to 15% by mass or less, 0.5% by mass or more to 10% by mass or less, or 1% by mass or more to 5% by mass or less.

[0056] The substrate layer 11 may further contain various additives, such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, a dehydrating agent, a crystal nucleating agent, and a tackifier, as needed.

[0057] The thickness of the substrate layer 11 is preferably 6 to 40 μm, and more preferably 10 to 30 μm. When the thickness of the substrate layer 11 is 6 μm or more, the pinhole resistance and insulating properties of the packaging material 10 tend to be improved. When the thickness of the substrate layer 11 is 40 μm or less, the total thickness of the packaging material 10 can be reduced.

[0058] In order to suppress deformation of the base layer 11 during sealing, the melting point of the base layer 11 is preferably higher than the melting point of the sealant layer 16, and more preferably 30°C or more higher than the melting point of the sealant layer 16.

[0059] <First Adhesive Layer> The first adhesive layer 12 is a layer that bonds the base material layer 11 and the metal foil layer 13. Specific examples of materials constituting the first adhesive layer 12 include polyurethane resins in which a bifunctional or higher isocyanate compound (a polyfunctional isocyanate compound) is reacted with 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 with two or more types depending on the functions and performance required for the exterior packaging material 10. In addition to the above, epoxy-based adhesives containing an epoxy resin as a base material and a curing agent can also be used. The materials constituting the first adhesive layer 12 are not limited to the polyurethane resins or epoxy-based adhesives described above. Furthermore, various other additives and stabilizers may be blended with the above materials depending on the performance required for the first adhesive layer 12.

[0060] The thickness of the first adhesive layer 12 is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, conformability, processability, etc., it is preferably, for example, 1 to 10 μm, and more preferably 2 to 7 μm.

[0061] The first adhesive layer 12 may or may not contain a hydrogen sulfide adsorbent. When the first adhesive layer 12 contains a hydrogen sulfide adsorbent, the hydrogen sulfide adsorbent is contained not only in the hydrogen sulfide adsorbing layer 17 but also in the first adhesive layer 12. Therefore, when hydrogen sulfide permeates the packaging material 10, it is adsorbed not only by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorbing layer 17 but also by the hydrogen sulfide adsorbent in the first adhesive layer 12. Furthermore, since the first adhesive layer 12 is located on the opposite side of the sealant layer 16 with respect to the metal foil layer 13, even if water is generated as a result of the adsorption reaction of hydrogen sulfide by the hydrogen sulfide adsorbent contained in the first adhesive layer 12, the water does not easily permeate the metal foil layer 13. Therefore, water is less likely to penetrate into the bag formed using the packaging material 10, and the generation of hydrogen sulfide can be suppressed.

[0062] The first adhesive layer 12 may or may not contain a color developer. If the first adhesive layer 12 contains a color developer, when a defect such as a pinhole is present in the metal foil layer 13, discoloration of the first adhesive layer 12 becomes noticeable in the vicinity of the defect, making it easier to determine that the amount of hydrogen sulfide has become excessive and to identify the defect in the metal foil layer 13. If the hydrogen sulfide adsorption layer 17, the base layer 11, and the first adhesive layer 12 all contain color developers, the color developers may be the same or different.

[0063] <Metal Foil Layer> The metal foil layer 13 has a water vapor barrier property that prevents moisture from permeating the packaging material 10. The metal foil layer 13 may also have extensibility for deep drawing. Examples of metals that constitute the metal foil layer 13 include aluminum, stainless steel, and copper. In terms of mass (specific gravity), moisture resistance, processability, and cost, the metal foil layer 13 is preferably aluminum foil.

[0064] As the aluminum foil, soft aluminum foil that has been annealed can be preferably used 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 degreasing the aluminum foil, the degreasing treatment may be performed on only one side of the aluminum foil, or on both sides.

[0065] The thickness of the metal foil 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.

[0066] <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 layer 13. The first anti-corrosion treatment layer 14a serves to increase the adhesion between the metal foil layer 13 and the first adhesive layer 12. The second anti-corrosion treatment layer 14b serves to increase the adhesion between the metal foil layer 13 and the second adhesive layer 15. 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 (hereinafter simply referred to as "anti-corrosion treatment layers 14a, 14b") are formed, for example, by degreasing, hydrothermal conversion treatment, anodizing, chemical conversion treatment, or a combination of these treatments.

[0067] 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 a mixture thereof. Furthermore, by using an acid degreasing agent prepared by dissolving a fluorine-containing compound such as monosodium ammonium difluoride (sodium ammonium difluoride) in the inorganic acid, not only can the aluminum be degreased, but also a passive aluminum fluoride can be formed, particularly when an aluminum foil is used for the metal foil layer 13. Furthermore, acid degreasing agents are effective in terms of corrosion resistance. Examples of alkaline degreasing include a method using sodium hydroxide or the like.

[0068] 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.

[0069] Examples of chemical conversion treatments include immersion-type chemical conversion treatments and coating-type chemical conversion treatments. Examples of immersion-type chemical conversion treatments 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 mixed phases of these. The above-mentioned "mixed phases of these" refers to a mixture of treatment solutions used in chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, strontium hydroxide treatment, cerium treatment, and ruthenium treatment. Examples of coating-type chemical conversion treatments include a method in which a coating agent having corrosion prevention properties is applied to the metal foil layer 13.

[0070] When at least a part of the corrosion prevention treatment layers 14a, 14b is formed by any of these corrosion prevention treatments, i.e., hydrothermal conversion treatment, anodizing treatment, and 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 layer 13, there is no need to perform a degreasing treatment again when forming the corrosion prevention treatment layers 14a, 14b.

[0071] 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.

[0072] Furthermore, among the above treatments (degreasing treatment, hydrothermal transformation treatment, anodizing treatment, chemical conversion treatment, or a combination of these treatments), particularly hydrothermal transformation treatment and anodizing treatment dissolve the aluminum foil surface with a treatment agent to form aluminum compounds (boehmite, alumite) with excellent corrosion resistance. Therefore, a bicontinuous structure is formed from the metal foil layer 13 using aluminum foil to the corrosion prevention treatment layers 14a, 14b, and the above treatments are included in the definition of chemical conversion treatment. On the other hand, it is also possible to form the corrosion prevention treatment layers 14a, 14b using only a pure coating method, which is not included in the definition of chemical conversion treatment. One example of this method is a method using a sol of a rare earth element oxide, such as cerium oxide, with an average particle size of 100 nm or less, which has an aluminum corrosion prevention effect (inhibitor effect) and is also environmentally friendly. By using this method, it is possible to impart corrosion prevention effects to metal foils such as aluminum foil using a general coating method.

[0073] Examples of the rare earth element oxide sol include sols using various solvents such as aqueous solvents, alcoholic solvents, hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents. Of these, aqueous sols (sols using aqueous solvents) are preferred.

[0074] 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 in the packaging material 10: (1) Stabilizing the dispersion of the sol; (2) Improving the adhesion between the corrosion prevention treatment layers 14a, 14b and the metal foil layer 13 by utilizing the aluminum chelating ability of phosphoric acid; (3) Imparting corrosion resistance by capturing aluminum ions (passivation); and (4) Improving the cohesion of the corrosion prevention treatment layers (oxide layers) 14a, 14b by facilitating dehydration condensation of phosphoric acid even at low temperatures.

[0075] 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.

[0076] 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 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 makes it possible to form a layer that combines both corrosion prevention functionality and adhesion. Furthermore, although the stability of the coating liquid must be considered, a coating agent in which a rare earth element oxide sol and a polycationic polymer or a polyanionic polymer are preliminarily mixed into a one-component solution can be used to form a layer that combines corrosion prevention functionality and adhesion.

[0077] The mass per unit area of ​​the corrosion prevention treatment layers 14a and 14b is 0.005 to 0.200 g / m2, regardless of whether the corrosion prevention treatment layers 14a and 14b have a multi-layer structure or a single-layer structure. ２ is preferred, 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 metal foil 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 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 14 a and 14 b can be calculated from their specific gravity.

[0078] From the viewpoint of making it easier to maintain adhesion between the sealant layer 16 and the metal foil layer 13, 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 in an embodiment formed by subjecting the metal foil layer 13 to a chemical conversion treatment, or may be in an embodiment formed by subjecting the metal foil layer 13 to a chemical conversion treatment and containing a cationic polymer.

[0079] <Second Adhesive Layer> The second adhesive layer 15 is a layer that bonds the metal foil layer 13 and the sealant layer 16. The second adhesive layer 15 may be a layer obtained using an adhesive resin composition, or may be a layer obtained using an adhesive.

[0080] When the second adhesive layer 15 is a layer obtained using an adhesive resin composition, the adhesive resin composition is not particularly limited, but preferably contains a modified polyolefin resin.

[0081] 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.

[0082] 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.

[0083] 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 second adhesive layer 15.

[0084] When the second adhesive layer 15 is a layer obtained using an adhesive, a general adhesive for bonding the metal foil layer 13 and the sealant layer 16 can be used for the second adhesive layer 15.

[0085] When a second corrosion prevention treatment layer 14b is provided on the metal foil layer 13 and the second corrosion prevention treatment layer 14b has a layer containing at least one polymer selected from the group consisting of the above-mentioned cationic polymers and anionic polymers, the second adhesive layer 15 is preferably a layer containing a compound (hereinafter also referred to as a "reactive compound") that is reactive with the above-mentioned polymer contained in the second corrosion prevention treatment layer 14b.

[0086] For example, when the second corrosion prevention treatment layer 14b contains a cationic polymer, the second adhesive layer 15 contains a compound reactive with the cationic polymer. When the second corrosion prevention treatment layer 14b contains an anionic polymer, the second adhesive layer 15 contains a compound reactive with the anionic polymer. When the second corrosion prevention treatment layer 14b contains a cationic polymer and an anionic polymer, the second adhesive layer 15 contains a compound reactive with the cationic polymer and a compound reactive with the anionic polymer. However, the second adhesive layer 15 does not necessarily need to contain the above two types of compounds; it may also contain a compound reactive with both the cationic polymer and the anionic polymer. Here, "reactive" means forming a covalent bond with the cationic polymer or the anionic polymer. The second adhesive layer 15 may also contain an acid-modified polyolefin resin.

[0087] The compound reactive with the cationic polymer may be at least one compound selected from the group consisting of a polyfunctional isocyanate compound, a glycidyl compound, a compound having a carboxy group, and a compound having an oxazoline group.

[0088] Among these, polyfunctional isocyanate compounds are preferred because they have high reactivity with cationic polymers and are easy to form crosslinked structures.

[0089] The compound reactive with an anionic polymer may be at least one compound selected from the group consisting of a glycidyl compound and a compound having an oxazoline group. Among these, a glycidyl compound is preferred because of its high reactivity with an anionic polymer.

[0090] When the second adhesive layer 15 contains an acid-modified polyolefin resin, the reactive compound preferably also has reactivity with the acidic groups in the acid-modified polyolefin resin (i.e., forms a covalent bond with the acidic groups). This enhances adhesion to the second corrosion prevention treatment layer 14b. In addition, the acid-modified polyolefin resin forms a crosslinked structure, further improving the solvent resistance of the exterior material 10.

[0091] The content of the reactive compound is preferably 1 to 10 times the equivalent of the acidic groups in the acid-modified polyolefin resin. If the content of the reactive compound is 1 equivalent or more, the reactive compound will react sufficiently with the acidic groups in the acid-modified polyolefin resin. On the other hand, if the content of the reactive compound exceeds 10 times the equivalent, the crosslinking reaction with the acid-modified polyolefin resin will be fully saturated, and unreacted material will remain, raising concerns about a decrease in various performances. Therefore, for example, the content of the reactive compound is preferably 5 to 20 parts by mass (solid content ratio) per 100 parts by mass of the acid-modified polyolefin resin.

[0092] The acid-modified polyolefin resin is a polyolefin resin into which an acidic group has been introduced. Examples of the acidic group include a carboxyl group, a sulfonic acid group, and an acid anhydride group, with a maleic anhydride group and a (meth)acrylic acid group being particularly preferred. For example, the acid-modified polyolefin resin may be the same as the modified polyolefin resin used in the sealant layer 16.

[0093] The second adhesive layer 15 may contain various additives, such as elastomers, flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers, as needed.

[0094] The thickness of the second adhesive layer 15 is not particularly limited, but from the viewpoint of stress relaxation and moisture permeation, it is preferably the same as or less than the thickness of the sealant layer 16 .

[0095] <Sealant Layer> The sealant layer 16 is a layer that imparts heat-sealing properties to the packaging material 10, and is a layer that is disposed on the inner side and heat-sealed (thermally fused) when assembling the electricity storage device. The sealant layer 16 may be either a single-layer film or a multilayer film.

[0096] The sealant layer 16 contains a resin. Examples of the resin include polyolefin-based resins and polyester-based resins. These resins may be used alone or in combination of two or more.

[0097] Examples of polyolefin resins include low-density, medium-density, or high-density polyethylene; ethylene-α-olefin copolymer; polypropylene; block or random copolymers containing propylene as a copolymerization component; and propylene-α-olefin copolymers.

[0098] Examples of polyester resins include polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, and copolymers thereof. "These copolymers" refers to copolymers of the monomers that form polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, and polybutylene naphthalate (PBN) resin.

[0099] The sealant layer 16 may contain additives such as slip agents, antiblocking agents, antioxidants, light stabilizers, and flame retardants.

[0100] The sealant layer 16 may or may not contain a hydrogen sulfide adsorbent, but it is preferable that it does not contain a hydrogen sulfide adsorbent. In this case, gaps are prevented from forming between the resin contained in the sealant layer 16 and the hydrogen sulfide adsorbent due to poor compatibility between them, improving moisture barrier properties. Furthermore, because the sealant layer 16 does not contain a hydrogen sulfide adsorbent, which is a foreign substance to the resin, the heat seal strength can be increased.

[0101] The sealant layer 16 may or may not contain a color developer, but it is preferable that it does not contain a color developer. In this case, gaps are prevented from forming between the resin and the color developer contained in the sealant layer 16 due to poor compatibility between them, improving moisture barrier properties. Furthermore, because the sealant layer 16 does not contain a color developer, which is a foreign substance to the resin, the heat seal strength can be increased.

[0102] 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. The total thickness of the second adhesive layer 15 and the sealant layer 16 is preferably in the range of 5 to 100 μm, more preferably in the range of 20 to 85 μm, from the viewpoint of achieving both a thin film and improved heat seal strength in a high-temperature environment.

[0103] [Method of Manufacturing the Sheathing Material] Next, an example of a method of manufacturing the sheathing material 10 shown in Fig. 1 will be described. Note that the method of manufacturing the sheathing material 10 is not limited to the following method.

[0104] 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 metal foil layer 13, bonding the base material layer 11 and the metal foil layer 13 together using the first adhesive layer 12 to obtain a laminate, laminating a hydrogen sulfide adsorption layer 17 on the base material layer 11 of the laminate, further laminating a sealant layer 16 via a second adhesive layer 15 to produce a structure, and, if necessary, aging the obtained structure.

[0105] (Step of laminating corrosion prevention treatment layers 14a, 14b onto metal foil layer 13) This step is a step of forming corrosion prevention treatment layers 14a, 14b on the metal foil layer 13. As described above, examples of the method for this include subjecting the metal foil layer 13 to degreasing treatment, hydrothermal treatment, anodizing treatment, or chemical conversion treatment, or applying a coating agent having corrosion prevention properties.

[0106] Furthermore, when the corrosion prevention treatment layers 14a, 14b are multi-layered, the corrosion prevention treatment layers 14a, 14b can be formed, for example, by applying a coating liquid (coating agent) that constitutes the lower corrosion prevention treatment layer (metal foil layer 13 side) to the metal foil layer 13 and baking it to form a first layer, and then applying a coating liquid (coating agent) that constitutes the upper corrosion prevention treatment layer to the first layer and baking it to form a second layer, and repeating this process.

[0107] The degreasing treatment can be carried out by a spray method or an immersion method. The hydrothermal conversion treatment and anodizing treatment can be carried out by an immersion method. The chemical conversion treatment can be carried out by an immersion method, a spray method, a coating method, or the like, appropriately selected depending on the type of chemical conversion treatment.

[0108] The coating agent having corrosion prevention properties can be applied by various methods such as gravure coating, reverse coating, roll coating, and bar coating.

[0109] As described above, the various treatments may be performed on either one or both sides of the metal foil constituting the metal foil layer 13, but in the case of one-side treatment, the treated side is preferably the side on which the sealant layer 16 is laminated. Note that the above treatments may also be performed on the surface of the base material layer 11, as required.

[0110] The coating amount of the coating agent for forming the first layer and the second layer is 0.005 to 0.200 g / m ２ , or 0.010 to 0.100 g / m ２ may be.

[0111] When dry curing is required, the drying can be performed at a base material temperature in the range of 60 to 300° C. depending on the drying conditions of the corrosion prevention treatment layers 14 a and 14 b used. Here, the base material temperature refers to the temperature of the metal foil layer 13.

[0112] (Step of bonding substrate layer 11 and metal foil layer 13) This step is a step of bonding the metal foil layer 13 provided with corrosion prevention treatment layers 14a, 14b to the substrate layer 11 via the first adhesive layer 12 to obtain a laminate. Examples of bonding methods include dry lamination, non-solvent lamination, wet lamination, and the like, and bonding the metal foil layer 13 to the substrate layer 11 using the material that constitutes the first adhesive layer 12 described above. The first adhesive layer 12 is applied in a dry coating amount of 1 to 10 g / m. ２ or 2 to 7 g / m ２ It may be set in the range.

[0113] (Laminating Step of Hydrogen Sulfide Adsorption Layer) This step is a step of forming a hydrogen sulfide adsorption layer 17 on the surface of the substrate layer 11 of the laminate opposite to the metal foil layer 13. The hydrogen sulfide adsorption layer 17 may be a coating film or a film.

[0114] When the hydrogen sulfide-adsorbing layer 17 is a coating film, the hydrogen sulfide-adsorbing layer 17 can be formed by applying the above-mentioned resin composition (coating liquid) for forming a hydrogen sulfide-adsorbing layer to the substrate layer 11 and then heating it. As a method for applying the resin composition for forming a hydrogen sulfide-adsorbing layer, various methods such as gravure coating, reverse coating, roll coating, and bar coating can be used.

[0115] When dry curing is required, the drying can be carried out at a base temperature in the range of 60 to 300° C. depending on the drying conditions of the resin composition for forming the hydrogen sulfide adsorption layer used.

[0116] When the hydrogen sulfide adsorption layer 17 is a film, the hydrogen sulfide adsorption layer 17 may be laminated by directly extruding a material obtained by dry-blending the components of the resin composition for forming a hydrogen sulfide adsorption layer using an extrusion laminator. Alternatively, the hydrogen sulfide adsorption layer 17 may be laminated by first forming a hydrogen sulfide adsorption layer as a cast film using the resin composition for forming a hydrogen sulfide adsorption layer and then laminating the hydrogen sulfide adsorption layer. The lamination method may be the same as the method for laminating the metal foil layer 13 and the substrate layer 11. From the viewpoint of productivity, the formation speed (processing speed) of the hydrogen sulfide adsorption layer 17 may be, for example, 80 m / min or more. The laminate may be aged before laminating the hydrogen sulfide adsorption layer 17 on the laminate.

[0117] (Laminating step of second adhesive layer 15 and sealant layer 16) This step is a step of obtaining a structure by forming the second adhesive layer 15 and the sealant layer 16 on the surface of the metal foil layer 13 facing the corrosion prevention treatment layer 14b. The second adhesive layer 15 may be a layer obtained using a heat-fusible resin composition, or may be a layer obtained using an adhesive.

[0118] When the second adhesive layer 15 is a layer obtained using a heat-fusible resin composition, a method for laminating the second adhesive layer 15 and the sealant layer 16 includes a method of sandwich laminating the second adhesive layer 15 with the corrosion prevention treatment layer 14b and the sealant layer 16 using an extrusion laminator. In this case, the sealant layer 16 may be formed in advance as a cast film using a resin composition for forming a sealant layer. Furthermore, lamination can also be performed using a tandem lamination method or coextrusion method in which the second adhesive layer 15 and the sealant layer 16 are extruded. In this case, the second adhesive layer 15 and the sealant layer 16 may be formed by extruding granules obtained by melt blending in advance using a melt kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer, and then extruding the granules using an extrusion laminator. To form the second adhesive layer 15 and the sealant layer 16, a resin composition for forming the second adhesive layer containing the components of the second adhesive layer 15 and a resin composition for forming the sealant layer containing the components of the sealant layer 16 are used, respectively.

[0119] The second adhesive layer 15 may be laminated by directly extruding a material obtained by dry-blending the components of the resin composition for forming the second adhesive layer using an extrusion laminator.

[0120] The sealant layer 16 may be laminated by directly extruding a material obtained by dry-blending the components of the resin composition for forming a sealant layer using an extrusion laminator. From the viewpoint of productivity, the formation speed (processing speed) of the second adhesive layer 15 and the sealant layer 16 can be, for example, 80 m / min or more.

[0121] When the second adhesive layer 15 is a layer obtained using an adhesive, the second adhesive layer 15 and the sealant layer 16 can be laminated by bonding the sealant layer 16 to the second corrosion prevention treatment layer 14b side of the metal foil layer 13 via the second adhesive layer 15. Examples of bonding methods include wet lamination and dry lamination. In this case, the sealant layer can be a film that has been previously formed as a cast film using a resin composition for forming a sealant layer.

[0122] When the sealant layer 16 is attached by dry lamination, the resin composition for forming the second adhesive layer 15 is applied onto the second corrosion prevention treatment layer 14b, and after drying at a predetermined temperature to remove the solvent, the sealant layer 16 is laminated. The preferred dry application amount of the resin composition for forming the second adhesive layer is the same as that of the resin composition for forming the first adhesive layer 12.

[0123] By the lamination process of the second adhesive layer 15 and the sealant layer 16, a structure is obtained in which the hydrogen sulfide adsorption layer 17, the substrate layer 11, the first adhesive layer 12, the first corrosion prevention treatment layer 14a, the metal foil layer 13, the second corrosion prevention treatment layer 14b, the second adhesive layer 15, and the sealant layer 16 are laminated in this order, as shown in FIG. 1 .

[0124] (Aging Treatment Step) This step is a step of aging (curing) the structure. By aging the structure, it is possible to promote adhesion between the substrate layer 11, the first adhesive layer 12, the first corrosion prevention treatment layer 14a, and the metal foil layer 13, as well as adhesion between the metal foil layer 13, the second corrosion prevention treatment layer 14b, the second adhesive layer 15, and the sealant layer 16.

[0125] In this manner, the exterior packaging material 10 of this embodiment as shown in FIG. 1 can be manufactured.

[0126] [Electricity Storage Device] Next, an electricity storage device according to an embodiment of the present disclosure will be described with reference to FIG. 2. FIG. 2 is a perspective view of the electricity storage device according to an embodiment of the present disclosure. As shown in FIG. 2, the electricity storage device 50 includes an electricity storage element 52 and an outer bag 54 that houses the electricity storage element 52. The outer bag 54 is obtained using an outer packaging material 10. The electricity storage device 50 may further include two metal terminals (current extraction terminals) 53 that extend from the electricity storage element 52 and extract current to the outside. Here, the metal terminals 53 are sandwiched by the outer packaging material 10. A tab sealant may be interposed between the metal terminals 53 and the outer packaging material 10. The outer packaging bag 54 typically houses the electricity storage element 52 in an airtight state, but this does not necessarily have to be the case.

[0127] The electricity storage element 52 has a positive electrode, an electrolyte, and a negative electrode in this order.

[0128] In the exterior packaging material 10, the hydrogen sulfide adsorption layer 17 is the outermost layer, and the sealant layer 16 is the innermost layer. The exterior packaging bag 54 may be formed by folding one exterior packaging material 10 in half and heat-sealing the peripheral edges so that the hydrogen sulfide adsorption layer 17 is the outermost layer and the sealant layer 16 is the innermost layer (see FIG. 2 ), or by stacking two exterior packaging materials 10 together so that the sealant layers 16 face each other and heat-sealing the peripheral edges.

[0129] According to the electricity storage device 50, even if hydrogen sulfide is generated inside the outer bag 54, the hydrogen sulfide can be effectively adsorbed by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer 17 as the hydrogen sulfide permeates through the outer bag 54. Therefore, the electricity storage device 50 can prevent hydrogen sulfide generated inside the outer bag 54 from leaking out of the outer bag 54. Furthermore, because the hydrogen sulfide adsorption layer 17 is located on the opposite side of the metal foil layer 13 from the sealant layer 16, even if water is generated as a result of the adsorption reaction of hydrogen sulfide by the hydrogen sulfide adsorbent, the water does not easily permeate the metal foil layer 13 and therefore does not easily enter the outer bag 54. This prevents the electrolyte in the electricity storage element 52 housed inside the outer bag 54 from coming into contact with water, thereby preventing the generation of hydrogen sulfide due to a reaction between water and the electrolyte.

[0130] The electrolyte may be a liquid electrolyte or a solid electrolyte, and examples of the solid electrolyte include oxide-based solid electrolytes and sulfide-based solid electrolytes.

[0131] The metal terminal 53 is a part of the current collector that is taken out of the exterior material 10, and is made of a metal foil such as copper foil or aluminum foil.

[0132] Specific examples of the power storage device 50 include secondary batteries such as all-solid-state batteries, lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries, as well as electrochemical capacitors such as electric double-layer capacitors, and semi-solid batteries. The present disclosure is particularly useful when the power storage device 50 is an all-solid-state battery. When the power storage device 50 is an all-solid-state battery, that is, when the power storage element 52 is a power storage element having a solid electrolyte, hydrogen sulfide may be generated when the power storage element 52 comes into contact with moisture. Even in this case, however, the hydrogen sulfide is effectively adsorbed by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer 17 as it permeates the outer bag 54, thereby preventing the hydrogen sulfide from leaking outside the outer bag 54.

[0133] [Electricity Storage Device] Next, an electric storage device according to an embodiment of the present disclosure will be described with reference to FIG. 3 . FIG. 3 is a cross-sectional view that schematically illustrates an electric storage device according to an embodiment of the present disclosure. As shown in FIG. 3 , an electric storage device 60 includes a plurality of electric storage devices 50 and a housing 65 that houses the plurality of electric storage devices 50. A space 61 exists between the housing 65 and the plurality of electric storage devices 50. The electric storage device 60 may further include two or more metal terminals for extracting current generated in the plurality of electric storage devices 50 to the outside of the electric storage device 60. The plurality of electric storage devices 50 may be connected in series or in parallel.

[0134] According to the electrical storage device 60, even if hydrogen sulfide is generated in each of the electrical storage devices 50, the hydrogen sulfide can be effectively adsorbed by the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer 17 as the hydrogen sulfide passes through the exterior bag 54. Therefore, this electrical storage device 60 can prevent hydrogen sulfide generated in each of the electrical storage devices 50 from leaking into the space between the electrical storage device 50 and the housing 65. Furthermore, in the electrical storage device 50, the hydrogen sulfide adsorption layer 17 is located on the opposite side of the base material layer 11 from the sealant layer 16. Therefore, even if a malfunction of one of the electrical storage devices 50 causes hydrogen sulfide to leak from the exterior bag 54 of that electrical storage device 50 into the space 61 between the electrical storage device 50 and the housing 65, the hydrogen sulfide can be effectively adsorbed by the hydrogen sulfide adsorption layers 17 of the exterior bags 54 of the other electrical storage devices 50, thereby preventing hydrogen sulfide from leaking outside the housing 65. The material constituting the housing 65 is not particularly limited and may be, for example, a metal or a resin.

[0135] The present disclosure will be specifically described below based on examples, but the present disclosure is not limited to the following examples.

[0136] [Materials Used] The materials used in the Examples and Comparative Examples are shown below. <Base Agent for Forming Outermost Layer> As the base agent for forming the outermost layer, a polyurethane-based coating agent was used, which was obtained by adding a curing agent (product name: SP Curing Agent, manufactured by Toyo Ink Co., Ltd.) consisting of an adduct of hexamethylene diisocyanate (HDI) and toluene as a solvent to 100 parts by mass of a polyester polyol-based main agent (product name: Vylon 200, manufactured by Toyobo Co., Ltd.). The "outermost layer" was formed by adding hydrogen sulfide (hereinafter referred to as "H ２ When the layer contains an adsorbent (also referred to as "hydrogen sulfide adsorption layer"), it becomes a "hydrogen sulfide adsorption layer."

[0137] <H ２ S adsorbent and developer > H ２ Zinc oxide was used as the S adsorbent, and lead acetate was used as the developer.

[0138] <Base layer> The following base layer films A1, A2, B, C, or D were used as the base layer. (Base layer film A1) Easily moldable polyethylene terephthalate film (easily moldable PET, thickness 25 μm, manufactured by Unitika Ltd., corona treated on both sides) (Base layer film A2) Easily moldable polyethylene terephthalate film (easily moldable PET, thickness 25 μm, manufactured by Unitika Ltd., corona treated on one side) (Base layer film B) Easily moldable polyethylene terephthalate film (easily moldable PET, thickness 25 μm, manufactured by Unitika Ltd., corona treated on one side) ２ A film obtained by extruding a dry blend of S adsorbent and developer into a film by extrusion lamination, and then subjecting both sides of the resulting single-layer PET film to corona treatment. ２ The amounts of the S adsorbent and the color developer were each 3% by mass based on the total mass of the obtained base layer film. The thickness of the base layer film B was 25 μm. (Base layer film C) A film obtained in the same manner as the base layer film B except that no color developer was added. (Base layer film D) H ２ A film obtained in the same manner as in film C for base layer, except that the content of the S adsorbent was 0.01% by mass based on the total mass of the obtained film for base layer.

[0139] <Materials for Forming the First Corrosion Prevention Treatment Layer (Substrate Layer Side) and the Second Corrosion Prevention Treatment Layer (Sealant Layer Side)> The following (CL-1) and (CL-2) were used as materials for forming the first corrosion prevention treatment layer (substrate layer side) and the second corrosion prevention treatment layer (sealant layer side). (CL-1): "Sodium polyphosphate-stabilized cerium oxide sol" obtained by using distilled water as a solvent and adjusting the solids concentration to 10% by mass. The sodium polyphosphate-stabilized cerium oxide sol was obtained by blending 10 parts by mass of sodium salt of phosphoric acid with 100 parts by mass of cerium oxide. (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 solids concentration to 5% by mass.

[0140] <Metal Foil Layer (Thickness: 40 μm)> Annealed and degreased soft aluminum foil (manufactured by Toyo Aluminum Co., Ltd., product name "8079 material") was used.

[0141] <Adhesive for forming adhesive layer> As the adhesive for forming the adhesive layer, a polyurethane-based adhesive obtained by adding 15 parts by mass of a curing agent containing toluene diisocyanate (TDI) (product name: CAT10, manufactured by Toyo-Morton Co., Ltd.) to 100 parts by mass of a polyester polyol-based main agent (product name: AD502, manufactured by Toyo-Morton Co., Ltd.) was used.

[0142] <Resin for forming second adhesive layer> Acid-modified polypropylene (acid-modified PP) was used as the resin for forming the second adhesive layer. Modic (registered trademark) P555 ​​manufactured by Mitsubishi Chemical Corporation was used as the acid-modified polypropylene.

[0143] <Resin for forming sealant layer> Polypropylene (PP) PC684S manufactured by SunAllomer Co., Ltd. was used as the resin for forming the sealant layer.

[0144] [Production of Exterior Material] Example 1 First, first and second corrosion prevention treatment layers were provided on both sides of a metal foil layer by the following procedure. That is, the material (CL-1) was applied to both sides of the metal foil layer in a dry coating amount of 70 mg / m ２The layers were coated by microgravure coating so that the thickness of the coated layer was 20 mg / m², and then baked in a drying unit at 200°C. Thereafter, (CL-2) was applied to the layers formed of the material (CL-1) on both sides of the substrate in a dry coating amount of 20 mg / m². ２ In this way, first and second corrosion prevention treatment layers were formed on both sides of the metal foil layer.

[0145] Next, the substrate layer film A1 was attached to the first corrosion prevention treatment layer using an adhesive for forming an adhesive layer by dry lamination. That is, the adhesive for forming an adhesive layer was applied to the surface of the metal foil layer facing the first corrosion prevention treatment layer so that the thickness after curing was 5 μm, and the adhesive was heated and dried at 80 ° C for 1 minute, and then laminated to the substrate layer and aged at 80 ° C for 120 hours. In this way, a laminate (substrate layer / adhesive layer / first corrosion prevention treatment layer / metal foil layer / second corrosion prevention treatment layer) was obtained.

[0146] Next, the outermost layer, H, was formed on the base layer of the laminate obtained as described above. ２ The S adsorption layer was provided by the following procedure. First, a hydrogen sulfide adsorbent was added to a base agent for forming the outermost layer to obtain a composition for forming the outermost layer (coating liquid). Next, the composition for forming the outermost layer was applied to the substrate layer of the laminate using a bar coater, and then dried at 100°C for 1 minute. ２ The amount of adsorbent added to the base agent for forming the outermost layer was determined by the amount of H ２ H based on the total mass of the S adsorption layer ２ The amount of the composition for forming the outermost layer was set so that the content of the S adsorbent was 3% by mass. ２ The amount was set so that the thickness of the S adsorption layer would be 3 μm.

[0147] Finally, a second adhesive layer and a sealant layer were laminated in this order on the second corrosion prevention treatment layer. That is, the above laminate (second laminate) was set on the unwinding section of an extrusion laminator. Then, the second adhesive layer resin and the sealant layer resin were co-extruded from a T-die under processing conditions of 270 ° C and 80 m / min, thereby laminating the second adhesive layer and the sealant layer in this order on the second corrosion prevention treatment layer. In addition, the thickness ratio of the second adhesive layer and the sealant layer was 2:1, and the total thickness was 80 μm.

[0148] In this way, the packaging material for the electricity storage device according to Example 1 (H ２ The resulting structure was a carbon black (S adsorption layer / adhesive layer / first corrosion prevention treatment layer / metal foil layer / second corrosion prevention treatment layer / second adhesive layer / sealant layer).

[0149] (Examples 2 and 4 to 6) H ２ The packaging materials of Examples 2 and 4 to 6 were obtained in the same manner as in Example 1, except that the S adsorbent and the developer were mixed to prepare the composition for forming the outermost layer. ２ The content of S adsorbent and developer is ２ H based on the total mass of the S adsorption layer ２ The contents of the S adsorbent and the developer were adjusted to the values ​​shown in Table 1.

[0150] Example 3 An exterior packaging material of Example 3 was obtained in the same manner as in Example 2, except that the film B for base layer was used as the base layer instead of the film A1 for base layer.

[0151] (Comparative Example 1) The base agent for forming the outermost layer was H ２ An exterior packaging material of Comparative Example 1 was obtained in the same manner as in Example 1, except that no S adsorbent was added.

[0152] (Comparative Example 2) As the base layer, the base layer film A2 was used instead of the base layer film A1, and the corona-treated surface of the base layer film A2 was laminated on the metal foil layer side. ２ An exterior packaging material of Comparative Example 2 was obtained in the same manner as in Example 1, except that the S adsorption layer was not formed.

[0153] (Comparative Example 3) The base agent for forming the outermost layer was２ An exterior material of Comparative Example 3 was obtained in the same manner as in Example 1, except that the composition for forming the outermost layer was prepared by adding a color developer without adding an S adsorbent. ２ The amount was set so that the content of the S adsorption layer would be 3 mass % based on the total mass of the S adsorption layer.

[0154] Comparative Example 4 An exterior packaging material of Comparative Example 4 was obtained in the same manner as in Comparative Example 2, except that the film C for base layer was used as the base layer instead of the film A2 for base layer.

[0155] Comparative Example 5 An exterior packaging material of Comparative Example 5 was obtained in the same manner as in Comparative Example 2, except that the film D for base layer was used as the base layer instead of the film A2 for base layer.

[0156] [H ２ Evaluation of S adsorption] H for the packaging materials of Examples and Comparative Examples ２ The S adsorption was evaluated by the following procedure. First, a sheet measuring 50 mm x 50 mm was cut out from the packaging materials according to the Examples and Comparative Examples, and the sheet was attached to the inside of a 2 L Tedlar bag (a bag for gas collection) so that the inner wall of the Tedlar bag and the sealant layer of the packaging material were in contact with each other. At this time, H was inserted into the gap between the sheet and the Tedlar bag. ２ The four sides of the sheet were sealed with polyimide tape to prevent S from getting in. Next, the Tedlar bag was sealed, and then H in the Tedlar bag was removed. ２ Air and H were mixed so that the S concentration was 20 ppm. ２ The Tedlar bag was sealed again and left to stand at room temperature for 168 hours (1 week). ２ The S concentration was measured using a detector tube gas measuring instrument and evaluated based on the following evaluation criteria. The results are shown in Table 1. ２ The unit of S concentration "ppm" is "ppm by mass". (Evaluation criteria) ◯ (Pass): H ２ S concentration is 9 ppm or less × (fail): H ２ S concentration exceeds 9 ppm

[0157]

[0158] From the results shown in Table 1, the packaging materials of Examples 1 to 6 had a lower H2O content in the Tedlar bag after standing for 168 hours than the packaging materials of Comparative Examples 1 to 5. ２ It was found that the S concentration was sufficiently low. From the above, it was confirmed that the packaging material of the present disclosure can effectively adsorb hydrogen sulfide.

[0159] The present disclosure is outlined as follows. [1] An electrical storage device packaging material including, in this order, a hydrogen sulfide adsorption layer containing a hydrogen sulfide adsorbent, a substrate layer, a metal foil layer, and a sealant layer, wherein the hydrogen sulfide adsorbent is made of a metal oxide, and the content of the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer is 0.5% by mass or more. [2] The electrical storage device packaging material according to [1], wherein the substrate layer contains a hydrogen sulfide adsorbent, and the hydrogen sulfide adsorbent is made of a metal oxide. [3] The electrical storage device packaging material according to [1] or [2], wherein the content of the hydrogen sulfide adsorbent in the substrate layer is 0.5% by mass or more. [4] The electrical storage device packaging material according to any one of [1] to [3], wherein at least one of the hydrogen sulfide adsorption layer and the substrate layer further contains a color developer that changes color upon reaction with hydrogen sulfide, and the color developer is made of a metal salt of an acid. [5] The packaging material for a storage battery device according to [4], wherein the total content of the hydrogen sulfide adsorbent and the developer in the hydrogen sulfide adsorption layer or the base material layer is 30 mass% or less. [6] The packaging material for a storage battery device according to any one of [1] to [5], wherein the metal oxide comprises an oxide of a divalent metal. [7] The packaging material for a storage battery device according to any one of [1] to [6], wherein the hydrogen sulfide adsorption layer is obtained using a coating liquid containing the hydrogen sulfide adsorbent. [8] The packaging material for a storage battery device according to [7], wherein the coating liquid further comprises a binder resin, the binder resin comprising at least one of an acrylic resin and a urethane resin. [9] The packaging material for a storage battery device according to any one of [1] to [8], wherein the sealant layer comprises a resin and does not comprise a hydrogen sulfide adsorbent.

[10] The packaging material for a storage battery device according to any one of [1] to [9], further comprising an adhesive layer between the base material layer and the metal foil layer.

[11] An electricity storage device comprising: an outer bag; and an electricity storage element housed in the outer bag, wherein the outer bag is obtained using the packaging material for an electricity storage device according to any one of [1] to

[10] , wherein the hydrogen sulfide adsorption layer of the packaging material for an electricity storage device is the outermost layer, and the electricity storage element contains an electrolyte. Alternatively, an electricity storage device comprising: an outer bag; and an electricity storage element housed in the outer bag, wherein the outer bag comprises the packaging material for an electricity storage device according to any one of [1] to

[10] , wherein the hydrogen sulfide adsorption layer of the packaging material for an electricity storage device is the outermost layer, and the electricity storage element contains an electrolyte.

[12] The electricity storage device according to

[11] , wherein the electrolyte is a solid electrolyte.

[13] An electricity storage device comprising: a plurality of electricity storage devices; and a housing that houses the plurality of electricity storage devices, wherein the electricity storage devices are the electricity storage devices according to

[11] or

[12] .

[0160] INDUSTRIAL APPLICABILITY The exterior packaging material for an electricity storage device according to the present disclosure can effectively adsorb hydrogen sulfide and is therefore useful as an exterior packaging material for an electricity storage device such as an all-solid-state battery.

[0161] 10...outer packaging material for electricity storage device, 11...substrate layer, 13...metal foil layer, 15...second adhesive layer (adhesive layer), 16...sealant layer, 17...hydrogen sulfide adsorption layer, 50...electricity storage device, 60...electricity storage equipment, 65...casing

Claims

1. An exterior packaging material for an electric storage device comprising, in this order, a hydrogen sulfide adsorption layer containing a hydrogen sulfide adsorbent, a substrate layer, a metal foil layer, and a sealant layer, wherein the hydrogen sulfide adsorbent is made of a metal oxide, and the content of the hydrogen sulfide adsorbent in the hydrogen sulfide adsorption layer is 0.5 mass% or more.

2. The packaging material for a power storage device according to claim 1, wherein the base layer contains a hydrogen sulfide adsorbent, and the hydrogen sulfide adsorbent is made of a metal oxide.

3. The packaging material for a storage battery device according to claim 2, wherein the content of the hydrogen sulfide adsorbent in the base layer is 0.5 mass % or more.

4. The exterior packaging material for a storage battery device according to claim 1, wherein at least one of the hydrogen sulfide adsorption layer and the base layer further contains a color developer that changes color upon reaction with hydrogen sulfide, the color developer comprising a metal salt of an acid.

5. The packaging material for a storage battery device according to claim 4, wherein the total content of the hydrogen sulfide adsorbent and the color developer in the hydrogen sulfide adsorption layer or the substrate layer is 30 mass % or less.

6. The packaging material for a power storage device according to claim 1, wherein the metal oxide includes an oxide of a divalent metal.

7. The exterior packaging material for a power storage device according to claim 1, wherein the hydrogen sulfide adsorption layer is obtained using a coating liquid containing the hydrogen sulfide adsorbent.

8. The packaging material for a power storage device according to claim 7, wherein the coating liquid further contains a binder resin, and the binder resin contains at least one of an acrylic resin and a urethane resin.

9. The packaging material for an electricity storage device according to claim 1, wherein the sealant layer contains a resin but does not contain a hydrogen sulfide adsorbent.

10. The packaging material for an electricity storage device according to claim 1, further comprising an adhesive layer between the substrate layer and the metal foil layer.

11. An electricity storage device comprising: an outer bag; and an electricity storage element housed in the outer bag; the outer bag is obtained using the electricity storage device packaging material according to any one of claims 1 to 10; the hydrogen sulfide adsorption layer of the electricity storage device packaging material is the outermost layer; and the electricity storage element contains an electrolyte.

12. The electricity storage device according to claim 11, wherein the electrolyte is a solid electrolyte.

13. An electric storage device comprising: a plurality of electric storage devices; and a housing that houses the plurality of electric storage devices, wherein the electric storage devices are the electric storage devices according to claim 11.

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