Terminal film for power storage device and power storage device

Abstract

To provide an exterior material for an all-solid-state battery that can detect an abnormality in the all-solid-state battery at an early stage by changing the color of a terminal film when hydrogen sulfide is generated.SOLUTION: A terminal film 40 for a power storage device, which is arranged so as to cover a part of the outer peripheral surface of a metal terminal 30 electrically connected to the power storage device main body 50 constituting the power storage device 100 includes a hydrogen sulfide color developer whose color changes when the terminal film reacts with hydrogen sulfide.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a terminal resin film arranged to cover a portion of the outer surface of a terminal in an energy storage device including an energy storage device main body and a terminal electrically connected to the energy storage device main body, and to an energy storage device using the terminal resin film. [Background technology]

[0002] Known examples of power storage devices include secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries, as well as electrochemical capacitors such as electric double-layer capacitors. Among these, lithium-ion batteries, which have a high energy density, have attracted attention. While metal cans have traditionally been used as the exterior materials for lithium-ion batteries, multilayer films, which are lightweight, have excellent heat dissipation properties, and can be produced at low cost, are now being used.

[0003] Lithium-ion batteries that use the above multilayer film as an exterior material are called laminated lithium-ion batteries. The exterior material covers the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.) and prevents moisture from penetrating into the battery. Laminated lithium-ion batteries are manufactured, for example, by forming a recess in part of the exterior material by cold forming, accommodating the battery contents in the recess, folding back the remaining part of the exterior material, and heat-sealing the edges.

[0004] Laminated lithium-ion batteries are equipped with current extraction terminals (sometimes called "tab leads"). In order to improve adhesion between the current extraction terminals and the exterior material, a terminal resin film (sometimes called "tab sealant") may be placed to cover part of the outer periphery of the current extraction terminal.

[0005] Such secondary batteries, such as lithium-ion batteries, are widely used in portable electronic devices, electric vehicles and hybrid electric vehicles that use electricity as a power source, etc. As a battery with improved safety compared to lithium-ion batteries, all-solid-state lithium batteries that use inorganic solid electrolytes instead of organic solvent electrolytes have been studied. All-solid-state lithium batteries are safer than lithium-ion batteries in that they are less likely to experience thermal runaway due to short circuits, etc.

[0006] Among inorganic solid electrolytes, sulfide-based solid electrolytes have higher ionic conductivity than oxide-based solid electrolytes and offer many advantages for achieving higher-performance all-solid-state batteries. However, because all-solid-state batteries using sulfide-based solid electrolytes contain sulfur, the sulfur may react with moisture that has entered the battery, generating toxic hydrogen sulfide (HS). Therefore, there is a concern that this hydrogen sulfide may leak if the battery's exterior material is damaged. To prevent hydrogen sulfide leakage, Patent Documents 1 and 2, for example, propose all-solid-state batteries with a safety design that captures and detoxifies the generated hydrogen sulfide. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-103283 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-103288 Summary of the Invention [Problem to be solved by the invention]

[0008] In all-solid-state batteries using a sulfide-based solid electrolyte, the generation of hydrogen sulfide indicates the occurrence of some abnormality, such as the deterioration of the sulfide-based solid electrolyte or damage to the exterior material. It is desirable to promptly replace an all-solid-state battery experiencing such an abnormality. However, because hydrogen sulfide has a pungent odor but is colorless, it is difficult to detect its generation. Furthermore, even if the methods described in Patent Documents 1 and 2 can detoxify the generated hydrogen sulfide, they cannot resolve the abnormality in the all-solid-state battery itself, and may actually delay the discovery of the abnormality.

[0009] The present disclosure has been made in consideration of the problems associated with the above-described conventional techniques, and aims to provide a terminal film for covering a current extraction terminal, which enables early detection of abnormalities in an electricity storage device such as an all-solid-state battery, and an electricity storage device using the same. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present disclosure provides a terminal film for an energy storage device (hereinafter also simply referred to as "terminal film") that is arranged to cover the outer surface of a portion of a metal terminal that is electrically connected to the energy storage device main body that constitutes the energy storage device, and is characterized in that the terminal film contains a hydrogen sulfide developer that changes color upon reacting with hydrogen sulfide.

[0011] According to the terminal film for an electricity storage device, since the terminal film contains the color developer, when hydrogen sulfide is generated in an all-solid-state battery containing a sulfide-based solid electrolyte, the terminal film containing the color developer changes color, making it possible to visually detect the generation of hydrogen sulfide and to visually detect abnormalities in the all-solid-state battery at an early stage.

[0012] In the terminal film for a power storage device, the hydrogen sulfide developer may contain one or more of copper, lead, silver, manganese, nickel, cobalt, tin, and cadmium. Developers containing these elements easily react with sulfur in hydrogen sulfide to change color, and the color change is easily visible, making it easier to visually detect abnormalities in the all-solid-state battery at an early stage.

[0013] In the terminal film for an electricity storage device, the copper may be a material containing CuSO, the lead may be a material containing Pb(CHCOO), and the silver may be a material containing AgSO. A developer containing the above compounds reacts with sulfur in hydrogen sulfide and easily changes color, and the color change is easily visible, making it easier to visually detect abnormalities in the all-solid-state battery at an early stage.

[0014] The terminal film for an electricity storage device may further contain a material that decomposes or adsorbs hydrogen sulfide.

[0015] In the terminal film for a power storage device, the total amount of the hydrogen sulfide developer and the material that decomposes or adsorbs hydrogen sulfide may be 0.01% to 30% of the total amount of the layer in each layer. When the content of the developer is equal to or greater than the lower limit, the color change is more easily visible, and when the content is equal to or less than the upper limit, deterioration in the functionality (e.g., adhesion strength, sealing strength, etc.) of the layer containing the developer can be suppressed.

[0016] In the terminal film for an electricity storage device, the material that decomposes or adsorbs hydrogen sulfide may contain zinc oxide or zinc ions. A hydrogen sulfide adsorbent containing zinc oxide or zinc ions is preferred because it has excellent performance in adsorbing or decomposing hydrogen sulfide and is inexpensive and easy to handle. [Effects of the Invention]

[0017] According to the present disclosure, it is possible to provide a terminal film for an electricity storage device that allows an abnormality in an all-solid-state battery to be easily detected from its appearance at an early stage, and an all-solid-state battery using the same. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view illustrating an example of an all-solid-state battery. [Figure 2] FIG. 1 is a cross-sectional view schematically illustrating an example of an exterior packaging material for a power storage device. [Figure 3] FIG. 2 is a cross-sectional view schematically showing the configuration of a sealant layer included in the packaging material for an electricity storage device. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1, and is a cross-sectional view schematically illustrating the configuration of a tab (terminal film and metal terminal) of the all-solid-state battery. [Figure 5] FIG. 2 is a cross-sectional view schematically showing an example of the configuration of a terminal film. [Figure 6] FIG. 1 is a plan view schematically showing evaluation samples prepared in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0019] 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.

[0020] <Electricity storage device> Fig. 1 is a perspective view showing a schematic configuration of a power storage device according to this embodiment. In Fig. 1, an all-solid-state battery is illustrated as an example of the power storage device 100, and the following description will be given. The power storage device having the configuration shown in Fig. 1 may be called a battery pack or a battery cell.

[0021] The energy storage device 100 is an all-solid-state battery, and includes an energy storage device main body 50, an exterior material 10, a pair of metal terminals 30, and a terminal film (tab sealant) 40. The energy storage device main body 50 is a battery main body that performs charging and discharging. The exterior material 10 covers the surface of the energy storage device main body 50 and is disposed so as to come into contact with a portion of the terminal film 40.

[0022] [Exterior materials] 2 is a cross-sectional view showing an example of a cut surface of the exterior packaging material 10. The exterior packaging material 10 has a multilayer structure including, from the outside to the inside (the electricity storage device main body 50 side), a base material layer 11, a first adhesive layer 12, a barrier layer 13, a corrosion prevention treatment layer 14, a second adhesive layer 17, and a sealant layer 16, in this order.

[0023] (sealant layer) The sealant layer 16 is a layer that provides sealing properties to the packaging material 10 by heat sealing, and is a layer that is placed on the inside and heat sealed (thermally fused) when assembling the electricity storage device.

[0024] For example, thermoplastic resins such as polyolefin, polyamide, polyester, polycarbonate, polyphenylene ether, polyacetal, polystyrene, polyvinyl chloride, and polyvinyl acetate can be used for the sealant layer 16. From the viewpoint of heat resistance and sealing suitability, polyolefin, polyamide, and polyester are preferred. When laminating directly to the barrier layer without using an adhesive, it is preferred to use a material in which at least one layer in contact with the barrier layer is modified with acid, glycidyl, or the like.

[0025] Examples of polyolefin resins include low-density, medium-density, and high-density polyethylene, ethylene-α-olefin copolymers, polypropylene, and propylene-α-olefin copolymers. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer.

[0026] Examples of polyester resins include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). These polyester resins may be used alone or in combination of two or more. Also, copolymers of any acid and glycol may be used.

[0027] In order to impart sealing properties, heat resistance, and other functionalities, for example, antioxidants, slip agents, flame retardants, antiblocking agents, light stabilizers, dehydrating agents, tackifiers, crystal nucleating agents, plasticizers, etc. may be added.

[0028] The melting peak temperature of the sealant layer 16 varies depending on the application, but in the case of an exterior material for an all-solid-state battery, it is preferably 160 to 280° C. because this improves heat resistance.

[0029] Examples of the base resin material contained in the sealant layer 16 include polyester-based, polyolefin-based, and polyamide-based resins.

[0030] Polyester-based resins can be obtained by copolymerizing an acid component and a glycol component. Examples of acid components include phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, and sebacic acid. Examples of glycol components include ethylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, diethylene glycol, polytetramethylene glycol, cyclohexanedimethanol, and propanediol. According to the inventors' studies, the temperature at which the minor dispersion peak γ of typical PET (a copolymer of terephthalic acid and ethylene glycol) exists is outside the range of −130°C to −50°C, resulting in insufficient seal strength at room temperature. When a plasticizer is not incorporated into the sealant layer 16, the sealant layer 16 preferably contains a polyester-based resin in which one acid component is copolymerized with two or more glycol components.

[0031] Examples of polyolefin resins include polyethylene and polypropylene resins. Generally used polyolefin resins have poor heat resistance, so it is preferable to use polyethylene or polypropylene modified with amide or the like.

[0032] Examples of polyamide resins include nylon 6 and nylon 6,6.

[0033] The sealant layer 16 preferably contains a plasticizer in order to adjust the temperature at which the minor dispersion peak γ and the major dispersion peak α of the sealant layer 16 appear. Examples of plasticizers that can be used include ester compounds. Specific examples include glycol diesters, adipic acid esters, phthalic acid esters, diacetyl monoacylglycerol derivatives, and esters having an ether skeleton. Although this depends on the base resin material of the sealant layer 16, the content of the plasticizer in the sealant layer 16 is preferably 30 mass% or less based on the mass of the sealant layer 16. Adding an excessive amount of plasticizer to the sealant layer 16 tends to excessively lower the temperatures at which the minor dispersion peak γ and the major dispersion peak α appear, and also to reduce the cohesive strength.

[0034] The sealant layer 16 may have a single-layer structure or a multi-layer structure of two or more layers (see FIGS. 3(a) to 3(c)). When the sealant layer has a single-layer structure, its thickness is preferably 10 to 300 μm, and more preferably 20 to 100 μm. When the thickness of the sealant layer 16 is 10 μm or more, it is easy to ensure sealing properties and insulation properties, while when it is 300 μm or less, it is possible to ensure cell volume.

[0035] FIG. 3(b) is a cross-sectional view schematically illustrating a two-layer sealant layer 16. The sealant layer 16 shown in FIG. 3(b) includes a first resin layer 16a and a second resin layer 16b formed on the inner surface of the first resin layer 16a. The first resin layer 16a may be made of a different material from the second resin layer 16b, and may have a different thickness from the second resin layer 16b. The thicknesses of the first resin layer 16a and the second resin layer 16b are, for example, 5 to 300 μm, or may be 20 to 200 μm. As shown in FIG. 3(c), the sealant layer 16 may have a three-layer structure and further include a third resin layer 16c.

[0036] When the electrolyte of the all-solid-state battery is a sulfide-based electrolyte, the sealant layer 16 preferably contains a hydrogen sulfide adsorbent. By including a hydrogen sulfide adsorbent in the sealant layer 16, excellent sealing strength can be maintained at room temperature and at high temperatures even after exposure to hydrogen sulfide. Materials capable of absorbing or adsorbing hydrogen sulfide can be used as the hydrogen sulfide adsorbent. Specific examples include zinc oxide, amorphous metal silicates, hydroxides of zirconium and lanthanoid elements, tetravalent metal phosphates, potassium permanganate, sodium permanganate, aluminum oxide, iron hydroxide, silver sulfate, silver acetate, isocyanate compounds, aluminum silicate, potassium aluminum sulfate, zeolite, activated carbon, amine-based compounds, and ionomers.

[0037] The content of the hydrogen sulfide adsorbent in the sealant layer 16 is preferably 1 to 50 mass %, more preferably 2 to 25 mass %, and even more preferably 5 to 15 mass %, based on the mass of the sealant layer 16. When the content of the hydrogen sulfide adsorbent in the sealant layer 16 is 1 mass % or more, the hydrogen sulfide adsorption effect is exhibited, while when the content is 50 mass % or less, the sealant layer 16 can achieve both adhesion and sealant suitability. When the sealant layer 16 has a multilayer structure, all or some of the layers may contain the hydrogen sulfide adsorbent. Note that, although a layer other than the sealant layer 16 (e.g., the second adhesive layer 17) in the packaging material 10 may contain a sulfide-based electrolyte, it is preferable that at least the sealant layer 16 contains the hydrogen sulfide adsorbent in terms of the content of the hydrogen sulfide adsorbent.

[0038] (base material layer) The base layer 11 provides heat resistance in the sealing process when manufacturing the electricity storage device and plays a role in suppressing the occurrence of pinholes that may occur during molding and distribution. In particular, in the case of an exterior material for a large-scale electricity storage device, the base layer 11 can also provide scratch resistance, chemical resistance, insulation, etc.

[0039] The base layer 11 is preferably a layer made of a resin film formed from an insulating resin. Examples of the resin film include stretched or unstretched films such as polyester film, polyamide film, polypropylene film, and polyphenylene sulfide film. The base layer 11 may be a single-layer film made of any of these resin films, or a laminate film made of two or more of these resin films.

[0040] Among these, polyester film and polyamide film are preferred as the base layer 11 due to their excellent formability, and polyamide film is more preferred. These films are preferably biaxially stretched films. Examples of polyester resins constituting polyester films include polyethylene terephthalate. Examples of polyamide resins constituting polyamide films include nylon 6, nylon 6,6, copolymers of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), nylon 11, and nylon 12. Among these, nylon 6 (ONy) is preferred due to its excellent heat resistance, puncture strength, and impact strength.

[0041] Examples of the stretching method for the biaxially stretched film include sequential biaxial stretching, tubular biaxial stretching, simultaneous biaxial stretching, etc. From the viewpoint of obtaining better deep drawability, the biaxially stretched film is preferably one stretched by the tubular biaxial stretching method.

[0042] 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 exceeds 40 μm, the total thickness of the packaging material 10 tends to be large.

[0043] (First adhesive layer) The first adhesive layer 12 is a layer that bonds the base layer 11 and the barrier layer 13. Specific examples of materials that constitute the first adhesive layer 12 include polyurethane resins in which a bifunctional or higher 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 of two or more types depending on the functions and performance required of the exterior material. In addition, various other additives and stabilizers may be blended with the polyurethane resins described above depending on the performance required of the adhesive.

[0044] 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, more preferably 3 to 7 μm.

[0045] (barrier layer) The barrier layer 13 has water vapor barrier properties that prevent moisture from penetrating into the interior of the electricity storage device. The barrier layer 13 also has extensibility that allows for deep drawing. The barrier layer 13 can be made of various metal foils such as aluminum, stainless steel, and copper, as well as metal vapor deposition films, inorganic oxide vapor deposition films, carbon-containing inorganic oxide vapor deposition films, and films provided with these vapor deposition films. From the standpoints of mass (specific gravity), moisture resistance, processability, and cost, metal foils are preferred, and aluminum foil is more preferred.

[0046] As the aluminum foil, soft aluminum foil that has been annealed is particularly preferred because it can impart the desired ductility during molding. However, it is more preferable to use aluminum foil containing iron for the purpose of imparting further pinhole resistance and ductility during molding. The iron content in the aluminum foil is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%, based on 100 mass% of the aluminum foil. By having an iron content of 0.1 mass% or more, an exterior packaging material 10 having better pinhole resistance and ductility can be obtained. By having an iron content of 9.0 mass% or less, an exterior packaging material 10 having better flexibility can be obtained. Although untreated aluminum foil may be used, it is preferable to use aluminum foil that has been degreased. When degreasing aluminum foil, the degreasing treatment may be performed on only one side of the aluminum foil, or on both sides.

[0047] The thickness of the barrier layer 13 is not particularly limited, but is preferably 9 to 200 μm, more preferably 15 to 100 μm, in consideration of barrier properties, pinhole resistance, and processability.

[0048] (Corrosion prevention treatment layer) The corrosion prevention treatment layer 14 is a layer provided to prevent corrosion of the barrier layer 13. The corrosion prevention treatment layer 14 is formed by, for example, degreasing treatment, hydrothermal treatment, anodizing treatment, chemical conversion treatment, or a combination of these treatments.

[0049] 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, alone or in combination. Furthermore, by using an acid degreasing agent prepared by dissolving a fluorine-containing compound such as monosodium ammonium difluoride in the inorganic acid, not only can the aluminum be degreased, but also a passive aluminum fluoride can be formed, which is effective in terms of corrosion resistance, particularly when an aluminum foil is used for the barrier layer 13. Examples of alkaline degreasing include a method using sodium hydroxide or the like.

[0050] 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.

[0051] The chemical conversion treatment may be an immersion type or a coating type. Examples of the immersion type chemical conversion treatment include chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, strontium hydroxide treatment, cerium treatment, ruthenium treatment, and various chemical conversion treatments consisting of a mixture of these. On the other hand, an example of the coating type chemical conversion treatment is a method in which a coating agent having corrosion prevention properties is applied to the barrier layer 13.

[0052] 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 beforehand. Note that when a degreased metal foil, such as a metal foil that has been subjected to an annealing process, is used as the barrier layer 13, there is no need to perform a degreasing treatment again when forming the corrosion prevention treatment layer 14.

[0053] The coating agent used in the spray-type chemical conversion coating 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.

[0054] 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 barrier layer 13 to the corrosion prevention treatment layer 14, and these treatments are included in the definition of chemical conversion treatment. On the other hand, as described below, it is also possible to form the corrosion prevention treatment layer 14 using a pure coating method, which is not included in the definition of chemical conversion treatment. One example of such a method is to use a sol of a rare earth oxide, such as cerium oxide, with an average particle size of 100 nm or less, which has an aluminum corrosion prevention effect (inhibitor effect) and is environmentally friendly. Using this method, it is possible to impart corrosion prevention effects to metal foils such as aluminum foil using a conventional coating method.

[0055] Examples of the rare earth element oxide sol include sols using various solvents such as water, alcohol, hydrocarbon, ketone, ester, and ether. Among these, water-based sols are preferred. To stabilize the dispersion of the rare earth element oxide sol, inorganic acids such as nitric acid, hydrochloric acid, and phosphoric acid or their salts, and organic acids such as acetic acid, malic acid, ascorbic acid, and lactic acid are typically used as dispersion stabilizers. Among these dispersion stabilizers, phosphoric acid is particularly expected to contribute to the exterior packaging material 10 by (1) stabilizing the dispersion of the sol, (2) improving adhesion to the barrier layer 13 by utilizing the aluminum chelating ability of phosphoric acid, and (3) improving the cohesion of the corrosion prevention treatment layer 14 (oxide layer) due to the tendency of phosphoric acid to undergo dehydration condensation even at low temperatures.

[0056] The corrosion prevention treatment layer 14 formed from the rare earth element oxide sol is an aggregate of inorganic particles, and therefore the cohesive strength of the layer itself may be reduced even after the dry-cure process. Therefore, in this case, the corrosion prevention treatment layer is preferably compounded with the following anionic polymer or cationic polymer to compensate for the cohesive strength.

[0057] The corrosion prevention treatment layer 14 is not limited to the layers described above. For example, it may be formed using a treatment agent in which phosphoric acid and a chromium compound are blended with a resin binder (such as aminophenol), as in the case of a known paint-type chromate. Use of 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 taken into consideration, 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.

[0058] The mass per unit area of ​​the corrosion prevention treatment layer 14 is 0.005 to 0.200 g / m 2 regardless of whether it is a multi-layer structure or a single-layer structure. 2 is preferable, and 0.010 to 0.100 g / m 2 If the mass per unit area is 0.005 g / m or more, it is easy to impart a corrosion prevention function to the barrier layer 13. Also, if the mass per unit area is 0.200 g / m or more, it is more preferable that the mass per unit area is 0.005 g / m or more. 2 Even if the thickness exceeds 1000 nm, 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 layer 14 can be calculated from its specific gravity.

[0059] From the viewpoint of adhesion between the sealant layer 16 and the barrier layer 13, the corrosion prevention treatment layer 14 may be in an embodiment containing, for example, cerium oxide, 1 to 100 parts by mass of phosphoric acid or a phosphate salt per 100 parts by mass of the cerium oxide, and a cationic polymer, or may be formed by subjecting the barrier layer 13 to a chemical conversion treatment, or may be formed by subjecting the barrier layer 13 to a chemical conversion treatment and contain a cationic polymer.

[0060] (Second adhesive layer) The second adhesive layer 17 is a layer that bonds the barrier layer 13, on which the corrosion prevention treatment layer 14 has been formed, to the sealant layer 16. For the second adhesive layer 17, a general adhesive for bonding the barrier layer 13 to the sealant layer 16 can be used.

[0061] When the corrosion prevention treatment layer 14 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 17 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 corrosion prevention treatment layer 14.

[0062] For example, if the corrosion prevention treatment layer 14 contains a cationic polymer, the second adhesive layer 17 contains a compound reactive with the cationic polymer. If the corrosion prevention treatment layer 14 contains an anionic polymer, the second adhesive layer 17 contains a compound reactive with the anionic polymer. If the corrosion prevention treatment layer 14 contains both a cationic polymer and an anionic polymer, the second adhesive layer 17 contains a compound reactive with the cationic polymer and a compound reactive with the anionic polymer. However, the second adhesive layer 17 does not necessarily have to contain both of these compounds; it may 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 17 may also contain an acid-modified polyolefin resin.

[0063] 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.

[0064] Examples of these polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group include the polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group exemplified above as crosslinking agents for forming a crosslinked structure from a cationic polymer. Among these, polyfunctional isocyanate compounds are preferred because they have high reactivity with cationic polymers and are easy to form a crosslinked structure.

[0065] The compound reactive with anionic polymers includes at least one compound selected from the group consisting of glycidyl compounds and compounds having an oxazoline group. These glycidyl compounds and compounds having an oxazoline group include the glycidyl compounds and compounds having an oxazoline group exemplified above as crosslinking agents for forming a crosslinked structure in cationic polymers. Among these, glycidyl compounds are preferred because of their high reactivity with anionic polymers.

[0066] When the second adhesive layer 17 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 further enhances adhesion to the corrosion prevention treatment layer 14. In addition, the acid-modified polyolefin resin forms a crosslinked structure, further improving the solvent resistance of the exterior packaging material 10.

[0067] The content of the reactive compound is preferably from 1 to 10 times the amount of the acidic groups in the acid-modified polyolefin resin. If the amount is equal to or greater than 10 times, the reactive compound will react sufficiently with the acidic groups in the acid-modified polyolefin resin. On the other hand, if the amount exceeds 10 times, the crosslinking reaction with the acid-modified polyolefin resin will be fully saturated, resulting in the presence of unreacted material, which may lead to 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.

[0068] 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.

[0069] The second adhesive layer 17 may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.

[0070] Examples of adhesives that form the second adhesive layer 17 include polyurethane resins in which a bifunctional or higher isocyanate compound is reacted with a base material such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol, and epoxy resins in which an amine compound or the like is reacted with a base material having an epoxy group, which are preferred from the standpoint of heat resistance.

[0071] The thickness of the second adhesive layer 17 is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, processability, etc., it is preferably 1 to 10 μm, and more preferably 2 to 7 μm.

[0072] [Metal terminal] Fig. 4 is a cross-sectional view of the terminal film and metal terminal shown in Fig. 1 along line IV-IV. Of the pair of metal terminals 30, 30, one metal terminal 30 is electrically connected to the positive electrode of the electricity storage device main body 50, and the other metal terminal 30 is electrically connected to the negative electrode of the electricity storage device main body 50. The pair of metal terminals 30, 30 extend from the electricity storage device main body 50 to the outside of the exterior material 10. The shape of the pair of metal terminals 30, 30 may be, for example, a flat plate shape.

[0073] Metals can be used as the material for the metal terminals 30. The metal to be used as the material for the metal terminals 30 can be determined taking into consideration the structure of the energy storage device main body 50, the materials of its components, and the like. For example, when the energy storage device 100 is an all-solid-state battery, aluminum is preferably used as the material for the metal terminal 30 connected to the positive electrode of the energy storage device main body 50. Copper with a nickel plating layer formed on the surface, or nickel, is preferably used as the material for the metal terminal 30 connected to the negative electrode of the energy storage device main body 50.

[0074] The thickness of the metal terminal 30 depends on the size and capacity of the all-solid-state battery. In the case of a small all-solid-state battery, the thickness of the metal terminal 30 may be, for example, 50 μm or more. In the case of a large all-solid-state battery for power storage, vehicle use, etc., the thickness of the metal terminal 30 may be appropriately set within the range of, for example, 100 to 500 μm.

[0075] [Terminal film] 4, the terminal film 40 is arranged so as to cover part of the outer circumferential surface of the metal terminal 30. By arranging the terminal film 40 between the metal terminal 30 and the exterior packaging material 10, it is possible to achieve even higher levels of sealing and insulation of the energy storage device 100.

[0076] (hydrogen sulfide developer) The terminal film 40 contains a hydrogen sulfide developer that changes color upon reaction with hydrogen sulfide. All-solid-state batteries typically use sulfide-based electrolytes, oxide-based electrolytes, organic polymer-based electrolytes, and the like as electrolytes. When a sulfide-based electrolyte is used, moisture that has entered the battery may react with sulfur to generate toxic hydrogen sulfide (H2S). Since the terminal film 40 contains a hydrogen sulfide developer, the terminal film 40 changes color when hydrogen sulfide is generated, allowing visual detection of the generation of hydrogen sulfide. Visual detection may be performed visually, or using a magnifying glass, microscope, or the like.

[0077] The terminal film 40 may have a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, the hydrogen sulfide developer may be contained in one or more of the layers. Examples of hydrogen sulfide developers include copper, lead, silver, manganese, nickel, cobalt, tin, and cadmium. These elements may be contained in the form of metals or ions, either singly or in combination. Compounds may also be included; for example, copper may be a material containing CuSO4, lead may be a material containing Pb(CH3COO)2, and silver may be a material containing Ag2SO4.

[0078] (Hydrogen sulfide deodorant) The terminal film 40 also preferably contains a substance that decomposes or adsorbs hydrogen sulfide. When the electrolyte of an all-solid-state battery is a sulfide-based electrolyte, the intrusion of moisture into the cell generates hydrogen sulfide, raising concerns about a decrease in the adhesion between the metal terminal (tab lead) 30 and the terminal film (tab sealant) 40. A decrease in adhesion can also lead to the leakage of hydrogen sulfide to the outside, resulting in the generation of an unpleasant odor. Adding a substance that decomposes or adsorbs hydrogen sulfide can maintain seal strength at room temperature and high temperatures, even when hydrogen sulfide is generated, and can also suppress the generation of unpleasant odors. Therefore, substances that decompose or adsorb hydrogen sulfide are also hydrogen sulfide deodorizers, and hereinafter, these substances will be referred to as hydrogen sulfide deodorizers.

[0079] Examples of substances that decompose or adsorb hydrogen sulfide (hydrogen sulfide deodorizers) include, but are not limited to, zinc oxide, amorphous metal silicates, hydroxides of zirconium and lanthanoid elements, tetravalent metal phosphates, potassium permanganate, sodium permanganate, aluminum oxide, iron hydroxide, silver sulfate, silver acetate, isocyanate compounds, aluminum silicates, tetravalent metal phosphates, potassium aluminum sulfate, zeolite, activated carbon, amine compounds, ionomers, etc. By including the above-mentioned hydrogen sulfide deodorizers in the terminal film 40, excellent sealing strength can be maintained at room temperature and high temperatures even after exposure to hydrogen sulfide, and the generation of unpleasant odors can be suppressed.

[0080] The total amount of the hydrogen sulfide developer and the hydrogen sulfide deodorizer in the terminal film 40 is preferably 0.01% to 30% by mass in each layer, based on the mass of the terminal film 40. When the content of the hydrogen sulfide developer and the hydrogen sulfide deodorizer in each layer of the terminal film 40 is 0.01% by mass or more, the hydrogen sulfide absorption or adsorption effect is exhibited, while when the content is 30% by mass or less, both the adhesion and the sealant suitability of the terminal film 40 can be achieved. When the terminal film 40 has a multilayer structure, from the viewpoint of adhesion to the metal terminal 30, it is preferable that the layer in contact with the metal terminal 30 does not contain the hydrogen sulfide developer and the hydrogen sulfide deodorizer. That is, it is preferable that the layer in contact with the exterior material 10 (for example, the resin layer 40a in Figure 5(b) or the resin layers 40a, 40c in Figure 5(c)) contains a hydrogen sulfide developer and a hydrogen sulfide deodorizer, and if the terminal film 40 consists of three or more layers, it is preferable that the intermediate layer (for example, the resin layer 40a in Figure 5(c)) contains a hydrogen sulfide developer and a hydrogen sulfide deodorizer.

[0081] The resin constituting the terminal film 40 can be a polyolefin resin such as polyethylene (LDPE, LLDPE, HDPE), polypropylene (homo, block, random), polybutene, or polyester resin. From the viewpoint of heat resistance and flexibility, polypropylene is preferred, and block polypropylene is particularly preferred. Acid-modified polyolefins can also be used, such as acid-modified polyolefin resins modified with unsaturated carboxylic acids, acid anhydrides of unsaturated carboxylic acids, or esters of unsaturated carboxylic acids.

[0082] Examples of polyester resins include polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, and copolymers thereof.

[0083] (acid-modified polyolefin resin) Acid-modified polyolefin resins are polyolefin resins into which acidic groups have been introduced. Examples of acidic groups include carboxyl groups, sulfonic acid groups, and acid anhydride groups, with maleic anhydride groups and (meth)acrylic acid groups being particularly preferred. The acid-modified polyolefin resin may be, for example, a modified polypropylene resin such as an acid-modified polypropylene resin. The modified polypropylene resin is preferably a resin in which an unsaturated carboxylic acid derivative component derived from an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, or an ester of an unsaturated carboxylic acid is graft-modified onto the polypropylene resin. In this case, examples of the polypropylene resin include homopolypropylene and random polypropylene.

[0084] Compounds used for graft-modifying these polypropylene resins include unsaturated carboxylic acid derivative components derived from unsaturated carboxylic acids, acid anhydrides of unsaturated carboxylic acids, and esters of unsaturated carboxylic acids.

[0085] Specific 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.

[0086] Examples of the 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 anhydride.

[0087] Examples of the 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 citraconate, dimethyl tetrahydrophthalate, and dimethyl bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylate.

[0088] The modified polypropylene resin can be produced by graft polymerization (graft modification) of 0.2 to 100 parts by mass of the unsaturated carboxylic acid derivative component described above to 100 parts by mass of the base polypropylene resin in the presence of a radical initiator. The reaction temperature for the graft modification is preferably 50 to 250°C, more preferably 60 to 200°C. The reaction time is appropriately set depending on the production method. For example, in the case of melt graft polymerization using a twin-screw extruder, the reaction time is preferably within the residence time of the extruder, specifically 2 to 30 minutes, more preferably 5 to 10 minutes. The graft modification can be carried out under either normal pressure or pressurized conditions.

[0089] Examples of the radical initiator used for the graft modification include organic peroxides such as alkyl peroxides, aryl peroxides, acyl peroxides, ketone peroxides, peroxyketals, peroxycarbonates, peroxyesters, and hydroperoxides.

[0090] These organic peroxides can be appropriately selected and used depending on the conditions of the reaction temperature and reaction time described above. For example, in the case of melt graft polymerization using a twin-screw extruder, alkyl peroxides, peroxyketals, and peroxyesters are preferred, and specifically, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexyne-3, dicumyl peroxide, etc. are preferred.

[0091] As specific products, for example, the following can be used, and it is preferable to use acid-modified maleic acid. Maleic anhydride: Admer (Mitsui Chemicals), Modic (Mitsubishi Chemical), Toyotack (Toyobo), Sunstack (Sanyo Chemical).

[0092] As described above, the terminal film 40 has a single-layer structure or a multi-layer structure. When the terminal film 40 has a single-layer structure, the terminal film 40 is made of a resin layer 40a (see FIG. 5(a)). When the terminal film 40 has a multi-layer structure, the terminal film 40 only needs to include at least one resin layer (resin layer 40a) that satisfies the above conditions (see FIGS. 5(b) and 5(c)). When the terminal film 40 has a multi-layer structure, it is preferable that all layers be made of the same type of resin material in terms of adhesion between adjacent layers.

[0093] From the viewpoint of embeddability and insulation, the thickness of the terminal film 40 is preferably 15 μm or more, more preferably 30 to 300 μm, and even more preferably 50 to 200 μm. When the terminal film 40 has a resin layer with the above-mentioned composition, the terminal film 40 makes it possible to visually detect the generation of hydrogen sulfide and also to suppress the generation of unpleasant odors.

[0094] The terminal film 40 may contain additives as needed, such as plasticizers, antioxidants, slip agents, flame retardants, anti-bacterial agents, light stabilizers, dehydrating agents, and tackifiers.

[0095] Although the embodiments of the present disclosure have been described in detail above, the present invention is not limited to the above embodiments, and various modifications and variations are possible within the scope of the gist of the present disclosure as set forth in the claims.

[0096] For example, in the above embodiment, an embodiment in which the corrosion prevention treatment layer 14 is provided only on one surface (the second adhesive layer 17 side) of the barrier layer 13 has been exemplified, but the corrosion prevention treatment layer 14 may also be provided on the other surface (the first adhesive layer 12 side) of the barrier layer 13. Furthermore, for example, when the sealant layer 16 is attached to the barrier layer 13 by thermal lamination, the second adhesive layer 17 may be omitted. When the substrate layer 11 is provided by coating or application, the first adhesive layer 12 may not be provided. In the above embodiment, an all-solid-state battery has been exemplified as an electricity storage device to which the packaging material 10 is applied, but the packaging material 10 may also be applied to other electricity storage devices (for example, lithium ion batteries). [Example]

[0097] Hereinafter, the present disclosure will be described more specifically based on examples, but the present disclosure is not limited to the following examples.

[0098] [Materials used] In order to fabricate the terminal films according to the examples and comparative examples, the following materials were prepared. <Resin materials> Resin A: A blend of block polypropylene (Novatec PP, manufactured by Nippon Polypropylene) and maleic anhydride-modified polyolefin (Toyotack, manufactured by Toyobo). Resin B: Block polypropylene (Novatec PP, made by Nippon Polypropylene). Resin C: A blend of random polypropylene (F744NP, manufactured by Prime Polymer) and maleic anhydride-modified polyolefin (Toyo Tack, manufactured by Toyobo).

[0099] <Developer> In the examples, the following color developers a to c were added to each layer of the terminal film. Whether or not they were added and the amount added are shown in Table 1. The amount added is shown as the percentage (mass%) of the total amount (100 mass%) of each layer. The color developers were mixed with the materials constituting each layer. Developer a: Lead acetate (Pb(CH3COO)2) Color developer b: Copper sulfate (CuSO4) Color developer c: Silver sulfate (Ag2SO4)

[0100] <Hydrogen sulfide (H2S) deodorant> In some examples and comparative examples, the following hydrogen sulfide deodorants A to C were added to each layer. Whether or not they were added and the amount added are shown in Table 1. The amount added is shown as the percentage (% by mass) of the total amount (100% by mass) of each layer. The hydrogen sulfide deodorant was mixed with the material constituting each layer. Hydrogen sulfide deodorizer A: Zinc oxide (ZnO, white pigment) Hydrogen sulfide deodorizer B: Daimshoe PE-M 3000-Z, polyethylene masterbatch product (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) Hydrogen sulfide deodorizer C: Kesmon NS10C (manufactured by Toagosei Co., Ltd.).

[0101] <Layer configuration> · Single layer: A single layer of resin A was used (Examples 1 to 11, Comparative Examples 1 and 2). · Multi-layer: Three-layer structure of resin C / resin B / resin C (Examples 12 and 13). The thickness of each layer is shown in Table 1.

[0102] [Evaluation method] (Sample preparation) For each example using the resin material, a terminal film sample was cut to 50 mm (TD) x 100 mm (MD). This was folded in half around a 50 mm x 50 mm cut piece of chemically treated aluminum. One side was heat sealed with a 10 mm wide seal bar at 165°C, 0.6 MPa, and 10 seconds. The heat-sealed portion was then cut to a 15 mm width. See Figure 6 for a rough outline of the sample.

[0103] <Initial seal strength> The seal strength was measured at room temperature (23°C) at a peel rate of 50 mm / min. The results were evaluated according to the following criteria. The results are shown in Table 1. A: Burst strength is 20N / 15mm or more. B: Burst strength is 15N / 15mm or more and less than 20N / 15mm. C: Burst strength less than 15N / 15mm.

[0104] <Hydrogen sulfide color development> If discoloration can be visually confirmed after 72 hours in a 2L container of 5ppm H2S at room temperature, it passes. Specifically, a terminal film sample is cut out to 50mm x 50mm and placed in a 2L Tedlar bag and sealed. 2L of 5ppm H2S gas is poured into the Tedlar bag containing the sample, and then left at room temperature for 72 hours, and the discoloration of the terminal film is checked.

[0105] <Hydrogen sulfide absorption> If the concentration is 10 ppm or less after 144 hours at room temperature in a 2L container containing 20 ppm H2S, it passes. Specifically, a terminal film sample is cut out to 50 mm x 50 mm and placed in a 2L Tedlar bag and sealed. 2L of 20 ppm H2S gas is poured into the Tedlar bag containing the sample, and then left at room temperature for 144 hours. If the concentration in the container is 10 ppm or less but higher than 5 ppm, it is evaluated as "△", and if it is 5 ppm or less, it is evaluated as "○". △ and ○ are considered to be passing.

[0106] Example 1 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 0.1% of developer a.

[0107] Example 2 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 0.3% of developer a.

[0108] Example 3 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 3% developer a.

[0109] Example 4 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 10% developer a.

[0110] Example 5 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 30% developer a.

[0111] Example 6 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 3% of developer b.

[0112] Example 7 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 3% developer c.

[0113] Example 8 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 1% developer a. Hydrogen sulfide deodorizer: Contains 3% hydrogen sulfide deodorizer A.

[0114] Example 9 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 3% developer a. Hydrogen sulfide deodorizer: Contains 10% hydrogen sulfide deodorizer A.

[0115] Example 10 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 0.1% of developer a. Hydrogen sulfide deodorizer: Contains 3% hydrogen sulfide deodorizer A.

[0116] Example 11 A resin film for terminals (single layer, thickness: 100 μm) made of the following resin composition was produced by an inflation method. Resin: Resin A · Hydrogen sulfide developer: Add 50% developer a.

[0117] Example 12 A three-layered resin film for terminals (25 μm / 50 μm / 25 μm) was produced by the inflation method. -Layer on exterior material side: 0.3% developer a added to resin C. · Middle layer: Resin B with 3% hydrogen sulfide deodorizer A added. Layer on metal terminal side: Resin C

[0118] Example 13 A three-layered resin film for terminals (25 μm / 50 μm / 25 μm) was produced by the inflation method. -Layer on exterior material side: Resin C with 0.3% developer a and 3% hydrogen sulfide deodorizer A added. · Middle layer: Resin B with 3% hydrogen sulfide deodorizer A added. Layer on metal terminal side: Resin C

[0119] (Comparative Example 1) The same procedure as in Example 1 was carried out except that no hydrogen sulfide developer was added.

[0120] (Comparative Example 2) The same procedure as in Example 1 was carried out except that no hydrogen sulfide developer was added and 3% of hydrogen sulfide deodorant A was added.

[0121] The evaluation results of the above examples and comparative examples are shown in Table 1.

[0122] [Table 1] [Industrial Applicability]

[0123] According to the terminal film for an electricity storage device of the present disclosure, the color of the terminal film changes when hydrogen sulfide is generated, allowing abnormalities in the all-solid-state battery to be detected visually at an early stage. [Explanation of symbols]

[0124] 10, 20... exterior material, 11... base material layer, 12... first adhesive layer, 13... barrier layer, 14... corrosion prevention treatment layer, 16... sealant layer, 17... second adhesive layer, 30... metal terminal, 40... terminal film, 50... electricity storage device main body, 100... electricity storage device

Claims

1. A terminal film for an electricity storage device is arranged to cover a part of an outer peripheral surface of a metal terminal electrically connected to an electricity storage device main body that constitutes the electricity storage device, the terminal film contains a hydrogen sulfide developer that changes color upon reacting with hydrogen sulfide, the terminal film for an electricity storage device has a single-layer structure, the content of the hydrogen sulfide developer is 0.01% by mass or more and 30% by mass or less, based on the mass of the terminal film for a power storage device; The terminal film for an electricity storage device, wherein the electricity storage device is an all-solid-state battery containing a sulfide-based solid electrolyte.

2. A terminal film for an electricity storage device is arranged to cover a part of an outer peripheral surface of a metal terminal electrically connected to an electricity storage device main body that constitutes the electricity storage device, the terminal film contains a hydrogen sulfide developer that changes color upon reacting with hydrogen sulfide, the terminal film for an electricity storage device has a multilayer structure and includes a layer containing the hydrogen sulfide developer, the content of the hydrogen sulfide developer in the layer is 0.01% by mass or more and 30% by mass or less, based on the mass of the layer; The terminal film for an electricity storage device, wherein the electricity storage device is an all-solid-state battery containing a sulfide-based solid electrolyte.

3. The terminal film for a power storage device according to claim 2 , wherein, of a plurality of layers constituting the terminal film for a power storage device, a layer in contact with the metal terminal does not contain the hydrogen sulfide developer.

4. 4. The terminal film for a storage device according to claim 2 or 3, wherein, among the multiple layers constituting the terminal film for a storage device, a layer that contacts an exterior material that constitutes the storage device together with the storage device main body contains the hydrogen sulfide developer.

5. the terminal film for an electricity storage device has a three-layer structure including a layer in contact with an exterior material that constitutes the electricity storage device together with the electricity storage device main body, an intermediate layer, and a layer in contact with the metal terminal, The terminal film for a power storage device according to any one of claims 2 to 4, wherein the intermediate layer contains the hydrogen sulfide developer.

6. The terminal film for a power storage device according to any one of claims 1 to 5, further comprising a material that decomposes or adsorbs hydrogen sulfide.

7. A terminal film for a storage device as described in Claim 6, wherein the material that decomposes or adsorbs hydrogen sulfide is selected from the group consisting of zinc oxide, amorphous metal silicates, hydroxides of zirconium and lanthanoid elements, tetravalent metal phosphates, potassium permanganate, sodium permanganate, iron hydroxide, silver sulfate, silver acetate, isocyanate compounds, aluminum silicate, potassium aluminum sulfate, zeolite, activated carbon, amine compounds, and ionomers.

8. The terminal film for an electricity storage device according to any one of claims 1 to 7, the power storage device main body that is charged and discharged; a pair of the metal terminals electrically connected to the power storage device main body and partially covered by the power storage device terminal film; an exterior material that covers a surface of the electricity storage device main body and is arranged so as to be in contact with a part of the electricity storage device terminal film; Equipped with An energy storage device that is an all-solid-state battery containing a sulfide-based solid electrolyte.

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