Power storage device exterior material and power storage device

Abstract

This power storage device exterior material comprises, in order, a base material layer, a barrier layer, an adhesive layer, and a sealant layer. In this power storage device exterior material, the adhesive layer is a thermal adhesive resin layer or a wet adhesive layer. If the adhesive layer is the thermal adhesive resin layer, the hydrogen sulfide permeation coefficient of a laminate of the thermal adhesive resin layer and the sealant layer is at least 1.1×10-9 cc∙mm / cm2∙sec∙cmHg and less than 1.0×10-8 cc∙mm / cm2∙sec∙cmHg, and if the adhesive layer is the wet adhesive layer, the hydrogen sulfide permeation coefficient of the sealant layer is at least 1.1×10-9 cc∙mm / cm2∙sec∙cmHg and less than 1.0×10-8 cc∙mm / cm2∙sec∙cmHg.

Description

Exterior material for power storage device and power storage device

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

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

[0003] As such an exterior material, for example, Patent Document 1 below discloses an exterior material for an all-solid-state battery including a sulfide solid electrolyte material, which is composed of a laminate including a base layer, a barrier layer, a barrier protection film formed on the surface of the barrier layer, and a heat-sealable resin layer in this order, and which is intended for use in an all-solid-state battery including a sulfide solid electrolyte material. The resin constituting the heat-sealable resin layer has a hydrogen sulfide permeability coefficient of 1.0 × 10 ―８ cc mm / cm ２ Furthermore, Patent Document 2 below discloses an all-solid-state battery packaging material for use in an all-solid-state battery containing a sulfide solid electrolyte material, which is composed of a laminate including a base layer, a barrier layer, and a heat-sealable resin layer in this order, and in which the resin constituting the heat-sealable resin layer has a hydrogen sulfide permeability coefficient of 1.0×10 ―９ cc mm / cm ２ An all-solid-state battery packaging material having a resistance of 1 / 2 sec cmHg or less is disclosed.

[0004] International Publication No. 2020 / 153458 International Publication No. 2020 / 002424

[0005] Incidentally, an electrical storage device packaging material may be stretched and shrunk in accordance with expansion and contraction of an electrical storage element during operation of the electrical storage device. However, both of the all-solid-state battery packaging materials disclosed in Patent Documents 1 and 2 have room for improvement, at least in terms of suppressing deterioration in insulating properties due to stretching.

[0006] The present disclosure has been made in view of the above circumstances, and aims to provide an exterior packaging material for an electricity storage device that can suppress deterioration in insulation properties due to stretching, and an electricity storage device.

[0007] One aspect of the present disclosure is a laminate including a base layer, a barrier layer, an adhesive layer, and a sealant layer in this order, wherein the adhesive layer is a thermal adhesive resin layer or an adhesive layer, and when the adhesive layer is the thermal adhesive resin layer, the hydrogen sulfide permeability coefficient of a laminate of the thermal adhesive resin layer and the sealant layer is 1.1 × 10 －９ cc mm / cm ２ ・sec・cmHg or more, 1.0×10 －８ cc mm / cm ２ sec cmHg, and when the adhesive layer is the adhesive layer, the hydrogen sulfide permeability coefficient of the sealant layer is less than 1.1 x 10 －９ cc mm / cm ２ ・sec・cmHg or more, 1.0×10 －８ cc mm / cm ２ Provided is an exterior material for an electricity storage device having a resistance to heat transfer of less than sec·cmHg.

[0008] The above-mentioned packaging material for an electricity storage device can suppress a decrease in insulating properties due to stretching. The inventors of the present disclosure speculate that the reason for this effect is as follows. That is, first, when the adhesive layer is a thermal adhesive resin, the hydrogen sulfide permeability coefficient of the laminate of the thermal adhesive resin layer and the sealant layer is 1.1 × 10, which is the lower limit. －９ cc mm / cm ２ If the permeability is less than 1.0 × 10 sec cmHg, the laminate becomes hard and brittle overall, which makes it more likely for cracks (microcracks) to occur in the laminate when the packaging material is stretched. －８ cc mm / cm ２When the pressure is 0.05 s·cmHg or higher, the laminate becomes soft overall, but when the packaging material is stretched, stress is concentrated in some hard parts of the laminate, making cracks more likely to occur. In contrast, when the hydrogen sulfide permeability coefficient of the laminate is within the above range as in the present disclosure, the laminate is neither too hard nor too soft, and even when stress is applied to the laminate when the packaging material is stretched, the stress is relaxed throughout the laminate, thereby suppressing the occurrence of cracks in the laminate. As a result, even when the packaging material is stretched, the deterioration of the insulating properties of the packaging material is suppressed. The inventors of the present disclosure speculate that, for the same reasons as above, even when the adhesive layer is an adhesive layer, the deterioration of the insulating properties of the packaging material is suppressed even when the packaging material is stretched.

[0009] In the electrical storage device packaging material, the sealant layer preferably contains a polypropylene-based resin containing at least one of homopolypropylene and block polypropylene, and a polyethylene-based resin, and the polyethylene-based resin has at least one melting peak in the range of 60° C. to 105° C. In this case, the dispersibility of the polyethylene-based resin in the polypropylene-based resin in the sealant layer is improved, and more efficient stress relaxation is obtained, thereby effectively suppressing deterioration in the insulating properties of the electrical storage device packaging material due to stretching.

[0010] In the packaging material for an electricity storage device, the ratio (Mw / Mn) of the weight average molecular weight Mw to the number average molecular weight Mn of the polyethylene resin is preferably 1.2 or more and 5.0 or less. In this case, the dispersibility of the polyethylene resin in the polypropylene resin in the sealant layer is further improved, and more efficient stress relaxation is obtained, so that deterioration in the insulating properties of the packaging material for an electricity storage device due to stretching is more effectively suppressed.

[0011] In the electrical storage device packaging material, the sealant layer preferably contains a polypropylene-based resin containing at least one of homopolypropylene and block polypropylene, and the content of the polypropylene-based resin in the sealant layer is preferably 50 to 95 mass%. In this case, the polypropylene-based resin is suitable for sealants and can impart appropriate hardness to the sealant layer. It can also balance the hardness and softness of the sealant layer. This more effectively prevents the deterioration of the insulating properties of the electrical storage device packaging material due to stretching.

[0012] In the electrical storage device packaging material, when the adhesive layer is the thermal adhesive resin layer, the thermal adhesive resin layer preferably contains a polypropylene-based resin, and the content of the polypropylene-based resin in the thermal adhesive resin layer is preferably 50 to 95 mass %. In this case, the hardness and softness of the thermal adhesive resin layer can be balanced. Therefore, deterioration of the insulating properties of the electrical storage device packaging material due to stretching can be more effectively suppressed.

[0013] In the electrical storage device packaging material, the sealant layer preferably contains a polypropylene-based resin including homopolypropylene and a polyethylene-based resin, and the ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn of the polyethylene-based resin (Mw / Mn) is 1.2 or more and 5.0 or less. In this case, the dispersibility of the polyethylene-based resin in the polypropylene-based resin is improved in the sealant layer, and efficient stress relaxation properties are obtained, so that deterioration in the insulating properties of the electrical storage device packaging material due to stretching is effectively suppressed.

[0014] In the electrical storage device packaging material, when the adhesive layer is the thermal adhesive resin layer, the total thickness of the laminate of the thermal adhesive resin layer and the sealant layer is preferably 25 to 150 μm, and when the adhesive layer is the adhesive layer, the thickness of the sealant layer is preferably 25 to 150 μm. In this case, the thermal adhesive resin layer and the sealant layer, or the sealant layer, have sufficient sealing properties and water vapor barrier properties, so that when an outer bag formed using the electrical storage device packaging material houses an electrical storage element, penetration of gases such as water vapor from outside the outer bag is more likely to be suppressed, and deterioration of the electrical storage element is more likely to be suppressed.

[0015] The electricity storage device is preferably an all-solid-state battery. In this case, even if the all-solid-state battery expands and contracts, deterioration in the insulating properties of the packaging material for an electricity storage device is suppressed.

[0016] Another aspect of the present disclosure provides an electricity storage device including an electricity storage element and an outer bag for housing the electricity storage element, the outer bag being formed using the outer material for an electricity storage device. According to the electricity storage device, even if the outer material for an electricity storage device is stretched due to expansion and contraction of the electricity storage element during operation of the electricity storage device, deterioration in the insulating properties of the outer bag formed using the outer material for an electricity storage device is suppressed, thereby enabling the electricity storage device to have a longer lifespan.

[0017] The electricity storage device is preferably an all-solid-state battery. In this case, the electricity storage element is particularly prone to expansion and contraction, but even if the electricity storage element expands and contracts, deterioration in the insulating properties of the outer packaging material for an electricity storage device due to stretching is suppressed, and therefore deterioration in the insulating properties of the outer packaging bag is suppressed, resulting in a longer life for the electricity storage device.

[0018] According to the present disclosure, there are provided an exterior packaging material for an electricity storage device and an electricity storage device that can suppress deterioration in insulation properties due to stretching.

[0019] Fig. 1 is a cross-sectional view schematically showing one embodiment of an exterior material for an electricity storage device according to the present disclosure. Fig. 2 is a cross-sectional view schematically showing another embodiment of an exterior material for an electricity storage device according to the present disclosure. Fig. 3 is a front view showing a measuring device for measuring hydrogen sulfide permeation amount. Fig. 4 is a perspective view of one embodiment of an electricity storage device according to the present disclosure.

[0020] 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.

[0021] [Exterior Material for Electricity Storage Device] Fig. 1 is a cross-sectional view schematically showing an exterior material for an electricity storage device according to one embodiment of the present disclosure. As shown in Fig. 1, an exterior material for an electricity storage device (hereinafter also simply referred to as "exterior material") 10 of this embodiment is an exterior material used for an electricity storage device, and includes, in this order, a base material layer 11, a barrier layer 13, a thermal adhesive resin layer 15 as an adhesive layer, and a sealant layer 16. Furthermore, as shown in Fig. 1, the exterior material 10 may include a first adhesive layer 12a between the base material layer 11 and the barrier layer 13.

[0022] This exterior packaging material 10 can suppress deterioration of insulation properties due to stretching.

[0023] The barrier 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 substrate layer 11 is the outermost layer and the sealant layer 16 is the innermost layer in the packaging material 10. In other words, the packaging material 10 is used with the substrate layer 11 facing outward from the electricity storage device and the sealant layer 16 facing inward from the electricity storage device.

[0024] Each layer constituting the exterior packaging material 10 will be specifically described below.

[0025] <Substrate Layer> The substrate layer 11 imparts heat resistance to the packaging material 10 in a sealing step of the packaging material 10 when manufacturing an electricity storage device, and plays a role in suppressing the occurrence of pinholes that may occur during molding, processing, or distribution of the packaging material 10. In particular, in the case of packaging materials for large-scale electricity storage devices, the substrate layer 11 can also impart scratch resistance, chemical resistance, insulating properties, and the like to the packaging material 10.

[0026] 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.

[0027] Among the resins mentioned above, 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, a copolymer of nylon 6 and nylon 6,6, nylon 9T, nylon 10, polymetaxylylene adipamide (MXD6), nylon 11, and nylon 12.

[0028] The substrate layer 11 may be in the form of a stretched or unstretched film, or in the form of a coating film. The substrate layer 11 may be a single layer or a multilayer. When the substrate layer 11 is a multilayer, it is formed by laminating layers made of different resins. When the substrate layer 11 is in the form of a film, a co-extruded laminate or a laminate laminated via an adhesive can be used as the substrate layer 11. When the substrate layer 11 is in the form of a coating film, a coating film obtained by coating a composition for forming a coating film multiple times can be used as the substrate layer 11. The substrate layer 11 can also be multilayered by combining a film and a coating film.

[0029] When the above-mentioned resin is used in the form of a film, the base material layer 11 is preferably a biaxially stretched film. In this case, the molding property of the packaging material 10 is improved. Examples of the stretching method used to obtain a biaxially stretched film include a sequential biaxial stretching method, a tubular biaxial stretching method, and a simultaneous biaxial stretching method. From the viewpoint of obtaining better deep-draw moldability of the packaging material 10, the biaxially stretched film is preferably a film stretched by a tubular biaxial stretching method.

[0030] The thickness of the substrate layer 11 is preferably 6 to 100 μm, more preferably 10 to 75 μm, and even more preferably 10 to 50 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 100 μm or less, the total thickness of the packaging material 10 can be reduced.

[0031] Furthermore, the substrate layer 11 preferably has a melting point higher than that of the sealant layer 16. When the substrate layer 11 or the sealant layer 16 has a multilayer structure, the melting point of the substrate layer 11 or the sealant layer 16 refers to the melting point of the layer with the highest melting point among the layers constituting the substrate layer 11 or the sealant layer 16, respectively. Having the substrate layer 11 have a melting point higher than that of the sealant layer 16 can prevent deterioration of the appearance of the packaging material 10 due to melting of the substrate layer 11 (outer layer) during heat sealing of the packaging material 10. Note that when multiple peak melting temperatures exist in each layer constituting the substrate layer 11 or the sealant layer 16, the melting point of each layer refers to the peak melting temperature with the largest heat of fusion. The peak melting temperature refers to the temperature at the maximum point of the melting peak.

[0032] Melting point T of the base layer 11 １１ and the melting point T of the sealant layer 16 １６ The difference between (T １１ -T １６ ) is preferably 20° C. or more. When this temperature difference is 20° C. or more, deterioration of the appearance of the packaging material 10 due to heat sealing of the packaging material 10 can be more sufficiently suppressed.

[0033] The melting temperature of the base layer 11 is preferably 240° C. or higher. However, the melting temperature of the base layer 11 is preferably 350° C. or lower. Examples of resin films that can be used as the base layer 11 and have a melting temperature in the above range include nylon films, polyester films such as PET films, polyamide films, and polyphenylene sulfide films (PPS films).

[0034] The substrate layer 11 may be a commercially available film or may be formed by coating (application of a coating liquid and drying). The substrate layer 11 may also be formed by applying a thermosetting resin. The substrate layer 11 may also contain various additives (e.g., flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, tackifiers, etc.).

[0035] <First Adhesive Layer> The first adhesive layer 12a is a layer that bonds the base material layer 11 and the barrier layer 13. Specific examples of materials that constitute the first adhesive layer 12a include polyurethane resins in which a bifunctional or higher isocyanate compound (a polyfunctional isocyanate compound) acts as a curing agent on a base material such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol. The various polyols described above can be used alone or in combination of two or more types depending on the functions and performance required of the exterior packaging material 10. In addition to the above, materials that contain an epoxy resin as a base material and a curing agent can also be used as materials that constitute the first adhesive layer 12a.

[0036] The first adhesive layer 12 a is formed using an adhesive composition containing the above-described base agent and curing agent. In addition, the first adhesive layer 12 a may contain various other additives and stabilizers in the above-described adhesive composition depending on the performance required of the adhesive layer.

[0037] The adhesive composition preferably contains, as a curing agent, at least one polyfunctional isocyanate compound selected from the group consisting of alicyclic isocyanate polymers and isocyanate polymers containing an aromatic ring in the molecular structure, such as a nurate of isophorone diisocyanate, an adduct of tolylene diisocyanate, an adduct of hexamethylene diisocyanate, a biuret and nurate of hexamethylene diisocyanate, a biuret and nurate of tolylene diisocyanate, an adduct, biuret and nurate of diphenylmethane diisocyanate, and an adduct, biuret and nurate of xylylene diisocyanate.

[0038] As the curing agent, an alicyclic isocyanate polymer and an isocyanate polymer containing an aromatic ring in the molecular structure may be used in combination. By using these in combination, the heat resistance of the exterior packaging material 10 tends to be further improved.

[0039] The adhesive composition preferably contains at least one polyol selected from the group consisting of polyester polyol, acrylic polyol, and polycarbonate diol, from the viewpoint of further improving the heat resistance of the packaging material 10. Among these adhesive compositions, the adhesive composition more preferably contains a polyester polyol, from the viewpoint of further improving the heat resistance of the packaging material 10.

[0040] In the adhesive composition, the ratio of the number of isocyanate groups contained in the polyfunctional isocyanate compound to the number of hydroxyl groups contained in the polyol (NCO / OH) may be 1.5 to 40.0, or may be 15.0 to 30.0. If this ratio is 1.5 or higher, the curing agents may react with each other, easily producing by-products such as urea resins and biuret resins. These by-products contain active hydrogen groups, which interact with polar groups in adjacent layers, further improving the interfacial adhesion between the first adhesive layer 12a and the substrate layer 11 and barrier layer 13. This tends to improve the heat resistance of the packaging material 10. On the other hand, if the ratio is 40.0 or lower, the laminate strength of the packaging material 10 can be further improved in room temperature and high-temperature environments.

[0041] The adhesive composition may further contain a tin-based, titanium-based, or zirconium-based urethanization catalyst to accelerate curing. The adhesive composition may also contain a latent curing agent or a viscous curing agent. Examples of the latent curing agent include amine-based compounds. The urethanization catalyst and the latent curing agent may each be used alone or in combination.

[0042] The thickness of the first adhesive layer 12a is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, followability, processability, etc. for the exterior material 10, it is preferably, for example, 1 to 10 μm, and more preferably 2 to 7 μm.

[0043] The mass per unit area of ​​the first adhesive layer 12a is set to 2.0 to 6.0 g / m from the viewpoint of ensuring superior lamination strength for the packaging material 10 both in a room temperature environment and a high temperature environment and obtaining superior deep drawability. ２ and 2.5 to 5.0 g / m ２ and 3.0 to 4.0 g / m ２ may be.

[0044] <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 may also have extensibility for deep drawing. Examples of the barrier layer 13 that can be used include various metal foils such as aluminum, stainless steel, and copper, as well as metal vapor-deposited films, inorganic oxide vapor-deposited films, carbon-containing inorganic oxide vapor-deposited films, and films having these vapor-deposited films. Examples of films having vapor-deposited films include aluminum vapor-deposited films and inorganic oxide vapor-deposited films. These films can be used alone or in combination of two or more. In terms of mass (specific gravity), barrier properties such as moisture resistance, processability, and cost, metal foils are preferred for the barrier layer 13, and aluminum foil or stainless steel foil is more preferred.

[0045] As the aluminum foil, soft aluminum foil that has been annealed is particularly preferred because it can impart the desired extensibility during molding to the barrier layer 13. To further impart pinhole resistance and extensibility during molding, it is more preferable to use aluminum foil containing iron. The iron content in the aluminum foil is preferably 0.1 to 9.0 mass% and 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 with better pinhole resistance and extensibility can be obtained. By having an iron content of 9.0 mass% or less, an exterior packaging material 10 with better flexibility can be obtained. Untreated aluminum foil may be used as the aluminum foil, but it is preferable to use aluminum foil that has been degreased 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.

[0046] 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 the barrier properties, pinhole resistance, and processability of the barrier layer 13.

[0047] <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 (metal foil layer) and the like that constitutes the barrier layer 13. The first anti-corrosion treatment layer 14a serves to increase the adhesion between the barrier layer 13 and the first adhesive layer 12a. The second anti-corrosion treatment layer 14b serves to increase the adhesion between the barrier layer 13 and the thermal adhesive resin 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.

[0048] 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, and a method using a mixture of these inorganic acids. Furthermore, in acid degreasing, it is preferable to use an acid degreasing agent prepared by dissolving a fluorine-containing compound such as monosodium ammonium difluoride in the inorganic acid. In this case, the aluminum degreasing effect can be obtained, particularly when an aluminum foil is used for the barrier layer 13. Furthermore, acid degreasing agents can form aluminum fluorides, which are passive, and are effective in terms of corrosion resistance. Examples of alkaline degreasing include a method using sodium hydroxide or the like.

[0049] 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.

[0050] 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. On the other hand, examples of coating-type chemical conversion treatments include a method in which a coating agent having corrosion prevention properties is applied to the barrier layer 13.

[0051] When at least a part of the corrosion prevention treatment layer is formed by any of these corrosion prevention treatments, i.e., hydrothermal conversion treatment, anodizing treatment, or chemical conversion treatment, it is preferable to perform the above-mentioned degreasing treatment beforehand. Note that when a degreased metal foil, such as a metal foil that has been subjected to an annealing process, is used as the barrier layer 13, there is no need to perform a degreasing treatment again when forming the corrosion prevention treatment layers 14a, 14b.

[0052] The coating agent used in the spray-type chemical conversion treatment preferably contains trivalent chromium. The coating agent may also contain at least one polymer selected from the group consisting of cationic polymers and anionic polymers.

[0053] 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, alumite) that have excellent corrosion resistance. Therefore, a bicontinuous structure is formed from the barrier layer 13 using the aluminum foil to the corrosion prevention treatment layers 14a, 14b, and therefore the above treatments are included in the definition of chemical conversion treatment.

[0054] As will be described later, it is also possible to form the corrosion prevention treatment layers 14a, 14b by a pure coating method that is not included in the definition of chemical conversion treatment. For example, one such method uses 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. By using this method, it is possible to impart corrosion prevention effects to metal foils, such as aluminum foils, even with a general coating method.

[0055] 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. Among these, aqueous solvent sols (sols using aqueous solvents) are preferred.

[0056] In order to stabilize the dispersion of the rare earth element oxide sol, inorganic acids such as nitric acid, hydrochloric acid, phosphoric acid, or their salts, or organic acids such as acetic acid, malic acid, ascorbic acid, and lactic acid are usually used as dispersion stabilizers. Of these dispersion stabilizers, phosphoric acid in particular is expected to have the following effects (1) to (4) in the packaging material 10: (1) stabilization of the sol dispersion; (2) improvement of the adhesion between the barrier layer 13 and the corrosion prevention treatment layers 14a, 14b by utilizing the aluminum chelating ability of phosphoric acid; (3) imparting corrosion resistance by capturing aluminum ions (passivation formation); and (4) improvement of the cohesion of the corrosion prevention treatment layers (oxide layers) 14a, 14b by the tendency of phosphoric acid to undergo dehydration condensation even at low temperatures.

[0057] 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.

[0058] The corrosion prevention treatment layers 14a, 14b are not limited to the layers described above. For example, the corrosion prevention treatment layers 14a, 14b 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 known coating-type chromate. Using this treatment agent allows the corrosion prevention treatment layers 14a, 14b to have both corrosion prevention properties and adhesion. Furthermore, although the stability of the coating liquid must be considered, the corrosion prevention treatment layers 14a, 14b can also be formed using a coating agent in which a rare earth element oxide sol and a polycationic polymer or a polyanionic polymer are preliminarily mixed into a single liquid.

[0059] The mass per unit area of ​​the corrosion prevention treatment layers 14a and 14b is 0.005 to 0.200 g / m2, whether the layer has a multi-layer structure or a single-layer structure. ２ It is preferable that the density is 0.010 to 0.100 g / m ２ It is more preferable that the mass per unit area is 0.005 g / m ２ If the mass per unit area is 0.200 g / m or more, it is easy to impart a corrosion prevention function to the barrier layer 13. ２ Even if the thickness exceeds 100 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.

[0060] From the viewpoint of making it easier to maintain adhesion between the sealant layer 16 and the barrier 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 barrier layer 13 to a chemical conversion treatment, or may be in an embodiment formed by subjecting the barrier layer 13 to a chemical conversion treatment and containing a cationic polymer.

[0061] <Thermal adhesive resin layer> The thermal adhesive resin layer 15 is a layer that bonds the sealant layer 16 and the barrier layer 13, and contains a thermal adhesive resin. The thermal adhesive resin is not particularly limited as long as it is a resin that has thermal adhesive properties, and may contain a polyolefin resin, but preferably contains an acid-modified polyolefin resin. In this case, the thermal adhesive resin layer 15 has sufficient adhesion to both the sealant layer 16 and the barrier layer 13.

[0062] The acid-modified polyolefin resin may be a polyolefin resin modified with at least one selected from the group consisting of maleic anhydride, carboxylic acid, sulfonic acid, and derivatives thereof. The acid-modified polyolefin resin may be, for example, a graft copolymer, a block copolymer, or a random copolymer. From the viewpoint of adhesion between the thermal adhesive resin layer 15 and the barrier layer 13, the acid-modified polyolefin resin is preferably a polyolefin resin graft-modified with maleic anhydride.

[0063] The polyolefin resin may be, for example, a polypropylene-based resin, a polyethylene-based resin, a polybutene-based resin, a polypentene-based resin, a polyoctene-based resin, or a polymethylpentene-based resin.

[0064] The polypropylene-based resin is a resin containing a resin obtained from a polymerized monomer containing propylene, and serves to impart hardness to the thermal adhesive resin layer 15. Examples of the polypropylene-based resin include homopolypropylene (homopolypropylene), block polypropylene (block PP), and random polypropylene. These may be used alone or in combination of two or more. From the viewpoint of being able to impart appropriate hardness to the thermal adhesive resin layer 15, it is preferable that the polypropylene-based resin contains at least one of homopolypropylene and block polypropylene.

[0065] The resin contained in the thermal adhesive resin layer 15 may further contain, in addition to the acid-modified polyolefin resin, an unmodified polyolefin resin such as a polyethylene-based resin, a polypropylene-based resin, a polybutene-based resin, a polypentene-based resin, a polyoctene-based resin, or a polymethylpentene-based resin.

[0066] Examples of polyethylene-based resins include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and polyethylene-based elastomers. These may be used alone or in combination of two or more. The polyethylene-based resin preferably contains a polyethylene-based elastomer, as this can impart softness to the thermal adhesive resin layer 15. As the polyethylene-based elastomer, an elastomer containing an α-olefin as a comonomer can be used. Specifically, such a polyethylene-based elastomer may be a compound obtained by copolymerizing ethylene with an α-olefin composed of at least one selected from 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene.

[0067] The content of the polypropylene-based resin in the thermal adhesive resin layer 15 is not particularly limited and may be, for example, 30 to 100% by mass. However, from the viewpoint of the balance between hardness and softness of the thermal adhesive resin layer 15, it is preferably 50 to 95% by mass, and more preferably 70 to 90% by mass.

[0068] The content of polyethylene resin in the thermal adhesive resin layer 15 is not particularly limited and may be, for example, 2 to 70% by mass. However, from the viewpoint of the balance between hardness and softness of the thermal adhesive resin layer 15, it is preferably 5 to 50% by mass, and more preferably 10 to 30% by mass.

[0069] When the thermal adhesive resin layer 15 contains a polypropylene-based resin and a polyethylene-based resin, one or both of the polypropylene-based resin and the polyethylene-based resin may be the same as or different from the polypropylene-based resin (A) and the polyethylene-based resin (B) contained in the sealant layer 16.

[0070] The thermal adhesive resin layer 15 may contain various additives, such as various compatible and incompatible elastomers, flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, crystal nucleating agents, and tackifiers, as needed.

[0071] <Sealant Layer> The sealant layer 16 is a layer that imparts heat-sealing properties to the exterior packaging material 10, and is a layer that is placed on the inside and heat-sealed (thermally fused) when assembling the electricity storage device. The sealant layer 16 is a layer that contains a resin that has heat-sealing properties. The resin that has heat-sealing properties preferably contains a polypropylene-based resin (A). The sealant layer 16 may or may not further contain a polyethylene-based resin (B). However, from the viewpoint of controlling the stress relaxation properties of the sealant layer 16 and making it easier to control the amount of hydrogen sulfide permeation, it is preferable that the sealant layer 16 further contains a polyethylene-based resin (B).

[0072] The polypropylene-based resin is a resin containing a resin obtained from a polymerized monomer including propylene, and serves to impart hardness to the sealant layer 16. Examples of the polypropylene-based resin include homopolypropylene (homopolypropylene), block polypropylene (block PP), and random polypropylene. These may be used alone or in combination of two or more. From the viewpoint of being suitable for use as a sealant and being able to impart appropriate hardness to the sealant layer 16, it is preferable that the polypropylene-based resin contains at least one of homopolypropylene and block polypropylene.

[0073] The polyethylene-based resin (B) is a resin obtained from a polymerized monomer containing ethylene, and serves to impart softness (stress relaxation properties) to the sealant layer 16. Examples of polyethylene-based resins include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and polyethylene-based elastomers. These may be used alone or in combination of two or more. The polyethylene-based resin preferably contains a polyethylene-based elastomer, as it can impart softness to the sealant layer 16 in particular.

[0074] The polyethylene elastomer may be an elastomer containing an α-olefin as a comonomer, specifically, an ethylene-α-olefin copolymer obtained by copolymerizing ethylene with at least one α-olefin selected from 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene.

[0075] The sealant layer 16 preferably contains a polypropylene-based resin (A) containing at least one of homopolypropylene and block polypropylene, and a polyethylene-based resin (B), and the polyethylene-based resin (B) has at least one melting peak in the range of 60° C. to 105° C. In this case, the dispersibility of the polyethylene-based resin in the polypropylene-based resin in the sealant layer 16 is improved, and more efficient stress relaxation is obtained, effectively suppressing deterioration in the insulating properties of the packaging material 10 due to stretching.

[0076] The melting peak temperature (hereinafter referred to as "melting peak temperature") is preferably in the range of 70°C or higher and 100°C or lower, more preferably 75°C or higher and 95°C or lower, and even more preferably 82°C or higher and 95°C or lower. When the sealant layer 16 contains a polyethylene-based resin having a melting peak in the above melting peak temperature range, the dispersibility of the polyethylene-based resin contained in the sealant layer 16 is improved, and efficient stress relaxation properties are obtained, thereby effectively suppressing deterioration in the insulating properties of the electrical storage device packaging material due to stretching. Note that the melting peak temperature in this specification is measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121-1987.

[0077] The ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn of the polyethylene resin (B) contained in the sealant layer 16 (hereinafter also referred to as "Mw / Mn") is not particularly limited, but is preferably 1.2 or more and 5.0 or less. Having the Mw / Mn of the polyethylene resin within the above range further improves the dispersibility of the polyethylene resin in the polypropylene resin in the sealant layer 16, resulting in more efficient stress relaxation, thereby more effectively suppressing the deterioration of the insulating properties of the electrical storage device packaging material due to stretching. Note that the number-average molecular weight Mn and weight-average molecular weight Mw herein refer to the number-average molecular weight Mn and weight-average molecular weight Mw determined in accordance with JIS K7252-1 and 4:2016 using gel permeation chromatography (GPC) at a measurement temperature of 145°C, converted into polystyrene. The Mw / Mn ratio is preferably 1.5 or more and 4.5 or less, more preferably 2.0 or more and 4.0 or less.

[0078] The content of the polypropylene resin in the sealant layer 16 is not particularly limited and may be, for example, 30 to 100% by mass. From the viewpoint of the balance between hardness and softness of the sealant layer 16, however, it is preferably 50 to 95% by mass, and more preferably 70 to 90% by mass.

[0079] The content of the polyethylene resin in the sealant layer 16 is not particularly limited and may be, for example, 2 to 70% by mass. From the viewpoint of the balance between hardness and softness of the sealant layer 16, however, it is preferably 5 to 50% by mass, and more preferably 10 to 30% by mass.

[0080] In addition to the polypropylene-based resin (A) and the polyethylene-based resin (B), the sealant layer 16 may contain other additive components as needed, such as slip agents, antiblocking agents, antioxidants, light stabilizers, crystal nucleating agents, flame retardants, etc. The content of these additive components is preferably 5% by mass or less, assuming that the total mass of the sealant layer 16 is 100% by mass.

[0081] From the viewpoint of improving the hardness of the sealed portion, the ratio of the thickness of the sealant layer 16 to the thickness of the thermal adhesive resin layer 15 (thickness of sealant layer 16 / thickness of thermal adhesive resin layer 15) is preferably 1 or more, more preferably 1.1 or more, and particularly preferably 1.5 or more. From the viewpoint of improving the hardness of the sealed portion, the ratio of the thickness of the sealant layer 16 to the thickness of the thermal adhesive resin layer 15 (thickness of sealant layer 16 / thickness of thermal adhesive resin layer 15) is preferably 10 or less, more preferably 3 or less.

[0082] The total thickness of the sealant layer 16 and the thermal adhesive resin layer 15 may be 15 to 300 μm, and from the viewpoint of the sealing property and water vapor barrier property of the exterior packaging material 10, it is preferably 25 to 150 μm, and more preferably 40 to 100 μm.

[0083] When an exterior material includes a thermally adhesive resin layer 15 and a sealant layer 16, as in exterior material 10, resin compositions for forming each layer may be prepared separately and laminated by the T-die method or the inflation method, or one layer may be formed and then laminated by extruding another layer on top of it, or each layer may be produced by the T-die method or the inflation method and then laminated by bonding them together with an adhesive. From the viewpoint of interfacial adhesion between the layer made of the adhesive and the layer to be bonded to this layer, an adhesive containing acid-modified polypropylene and a curing agent (e.g., isocyanate) can be used as the adhesive to be used.

[0084] <Laminate of Sealant Layer and Thermal Adhesive Resin Layer> The hydrogen sulfide permeability coefficient of the laminate 17 of the sealant layer 16 and the thermal adhesive resin layer 15 is 1.1×10 －９ cc mm / cm ２ ・sec・cmHg or more 1.0×10 －８ cc mm / cm ２ The hydrogen sulfide permeability coefficient of the laminate 17 is less than 1 / 2 sec cmHg. When the hydrogen sulfide permeability coefficient of the laminate 17 is within the above range, the laminate 17 is neither too hard nor too soft, and even when stress is applied to the laminate 17 when the packaging material 10 stretches, the stress is alleviated throughout the laminate 17, thereby suppressing the occurrence of cracks in the laminate 17. As a result, even when the packaging material 10 stretches, the deterioration of the insulating properties of the packaging material 10 is suppressed. The hydrogen sulfide permeability coefficient of the laminate 17 is preferably 2.5 × 10 －９ cc mm / cm ２ sec cmHg or more, more preferably 3.5 × 10 －９ cc mm / cm ２ The hydrogen sulfide permeability coefficient of the laminate 17 is preferably 8.5×10 －９ cc mm / cm ２ sec cmHg or less, more preferably 7.5 × 10 －９ cc mm / cm ２ sec cmHg or less, more preferably 6.5 × 10 －９ cc mm / cm ２In this specification, the hydrogen sulfide permeability coefficient of the laminate 17 refers to the hydrogen sulfide permeability coefficient in the thickness direction of the laminate 17.

[0085] The hydrogen sulfide permeability coefficient of the laminate 17 can be measured by a gas permeation test. A method for measuring the hydrogen sulfide permeability coefficient of the laminate 17 will be described below. (1) First, as shown in FIG. 3 , a measurement sample 35 cut out from the laminate 17 is placed between the upper part 31 of the separable flask and the lower part 36 of the separable flask. (2) Next, in an environment of the test temperature (23±5°C), nitrogen gas is passed through the vent 32 of the upper part 31 of the separable flask at a flow rate of 50 mL / min and exhausted through the vent 33. Meanwhile, hydrogen sulfide gas is passed through the vent 37 at a flow rate of 50 mL / min and exhausted through the vent 38. At this time, the hydrogen sulfide gas is passed together with the nitrogen gas so that the hydrogen sulfide gas concentration in the nitrogen gas is 20±5 ppm by volume. (3) Next, 24 hours after the start of aeration, a resin bag is connected to the vent port 33, and 0.5 L of sample gas is collected over 10 minutes. (4) Next, the concentration of the sample gas collected in the resin bag (hydrogen sulfide gas concentration in the sample gas) is measured using a gas chromatograph-flame photometric detector (GC-FPD). (5) The above operations (3) and (4) are also repeated 48 hours and 96 hours after the start of aeration. (6) The hydrogen sulfide permeation rate per hour (nL / hr) is calculated using the following formula 1 from the average value (average sample gas concentration) of the sample gas concentrations (unit: volume ppb) collected after 24 hours, 48 ​​hours, and 96 hours. (Calculation formula 1) Hydrogen sulfide permeation rate (nL / hr) = Average sample gas concentration (volume ppb ≒ nL / L) × Amount of collected gas per hour (*) (*) Because the flow rate of nitrogen gas, the test gas, is 50 mL / min, the amount of collected gas per hour is 3 L. From the obtained hydrogen sulfide permeation rate, the hydrogen sulfide permeability (cc / m), which is the amount of hydrogen sulfide permeation per unit area and per day, was calculated using the following calculation formula 2. ２ (Calculation Formula 2) Hydrogen sulfide permeability (cc / m ２ ・day)=Hydrogen sulfide permeation amount (nL / hr)×24(hr) / 10 ６ / effective test area (m２ The effective test area is the opening area of ​​the separable flask, which is 0.00453 m ２ (7) Finally, the unit of hydrogen sulfide permeability is cc mm / cm. ２ The hydrogen sulfide permeability coefficient is calculated by converting the value to sec cmHg.

[0086] Although the preferred embodiment of the exterior packaging material of the present embodiment has been described in detail above, the present disclosure is not limited to the specific embodiment described above.

[0087] For example, although FIG. 1 shows a case where the thermal adhesive resin layer 15 is used as the adhesive layer, a second adhesive layer 12b may be used as the adhesive layer as in the exterior material 20 shown in FIG.

[0088] <Second Adhesive Layer> Here, the second adhesive layer 12b will be described. The second adhesive layer 12b is a layer that bonds the barrier layer 13 and the sealant layer 16. A general adhesive for bonding the barrier layer 13 and the sealant layer 16 can be used for the second adhesive layer 12b.

[0089] When the second adhesive layer 12b is used as the adhesive layer, the hydrogen sulfide permeability coefficient of the sealant layer 16 is 1.1 x 10 －９ cc mm / cm ２ ・sec・cmHg or more, 1.0×10 －８ cc mm / cm ２ The hydrogen sulfide permeability coefficient of the sealant layer 16 is a value measured in the same manner as the method for measuring the hydrogen sulfide permeability coefficient of the laminate 17 described above. －９ cc mm / cm ２ sec·cmHg or more, the sealant layer 16 is neither too hard nor too soft, and even if stress is applied to the sealant layer 16 when the packaging material 20 stretches, the stress is alleviated by the sealant layer 16, thereby suppressing the occurrence of cracks in the sealant layer 16. As a result, even if the packaging material 20 stretches, the deterioration of the insulating properties of the sealant layer 16 can be suppressed, and the deterioration of the insulating properties of the packaging material 20 is suppressed.－８ cc mm / cm ２ By having a hydrogen sulfide permeability coefficient of 1000 kJ / s or less, the sealant layer 16 is neither too hard nor too soft, and even if stress is applied to the sealant layer 16 when the packaging material 20 stretches, the stress is alleviated by the sealant layer 16, thereby suppressing the occurrence of cracks in the sealant layer 16. As a result, even if the packaging material 20 stretches, the deterioration of the insulating properties of the packaging material 20 is suppressed. The hydrogen sulfide permeability coefficient of the sealant layer 16 is preferably 2.5 × 10 －９ cc mm / cm ２ sec cmHg or more, more preferably 3.5 × 10 －９ cc mm / cm ２ The hydrogen sulfide permeability coefficient of the sealant layer 16 is preferably 8.5×10 －９ cc mm / cm ２ sec cmHg or less, more preferably 7.5 × 10 －９ cc mm / cm ２ sec cmHg or less, more preferably 6.5 × 10 －９ cc mm / cm ２ ・sec・cmHg or less.

[0090] When the second adhesive layer 12b is used as the adhesive layer, the thickness of the sealant layer 16 may be 15 to 300 μm, and from the viewpoint of the sealing property and water vapor barrier property of the exterior material 20, it is preferably 25 to 150 μm, and more preferably 40 to 100 μm.

[0091] When a corrosion prevention treatment layer 14b is provided on the barrier layer 13 and the second corrosion prevention treatment layer 14b has a layer containing at least one polymer selected from the group consisting of cationic polymers and anionic polymers, the second adhesive layer 12b is preferably a layer containing a compound (hereinafter also referred to as a "reactive compound") that is reactive with the polymer contained in the second corrosion prevention treatment layer 14b.

[0092] For example, when the second corrosion prevention treatment layer 14b contains a cationic polymer, the second adhesive layer 12b preferably contains a compound reactive with the cationic polymer. When the second corrosion prevention treatment layer 14b contains an anionic polymer, the second adhesive layer 12b preferably contains a compound reactive with the anionic polymer. Furthermore, when the second corrosion prevention treatment layer 14b contains both a cationic polymer and an anionic polymer, the second adhesive layer 12b preferably contains both a compound reactive with the cationic polymer and a compound reactive with the anionic polymer. However, the second adhesive layer 12b does not necessarily need to contain both of these 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 12b may also contain an acid-modified polyolefin resin.

[0093] 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.

[0094] Examples of these polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group include polyfunctional isocyanate compounds, glycidyl compounds, compounds having a carboxy group, and compounds having an oxazoline group, which serve as crosslinking agents for forming a crosslinked structure from a cationic polymer. Among these compounds, polyfunctional isocyanate compounds are preferred because they have high reactivity with cationic polymers and are easy to form a crosslinked structure.

[0095] 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 or compounds having an oxazoline group include glycidyl compounds and compounds having an oxazoline group as crosslinking agents for forming a crosslinked structure in cationic polymers.Among these compounds, glycidyl compounds are preferred because of their high reactivity with anionic polymers.

[0096] When the second adhesive layer 12b contains an acid-modified polyolefin resin, the reactive compound is preferably reactive with the acidic groups in the acid-modified polyolefin resin (i.e., forms a covalent bond with the acidic groups). This further enhances the adhesion between the second adhesive layer 12b and 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 20.

[0097] 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 sufficiently saturated, and there will be unreacted material in the second adhesive layer 12b, which may result in a decrease in various performances. Therefore, for example, the content of the reactive compound is preferably 5 to 20 parts by mass (solids ratio) per 100 parts by mass of the acid-modified polyolefin resin.

[0098] 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.

[0099] The second adhesive layer 12b may contain various additives such as a flame retardant, a slip agent, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.

[0100] The second adhesive layer 12b may contain, for example, an acid-modified polyolefin and at least one curing agent selected from the group consisting of a polyfunctional isocyanate compound, a glycidyl compound, a compound having a carboxy group, a compound having an oxazoline group, and a carbodiimide compound, from the viewpoint of suppressing a decrease in the heat seal strength of the packaging material 10 and further suppressing a decrease in the insulating properties of the packaging material 10 when a corrosive gas such as hydrogen sulfide or an electrolyte is involved. Examples of the carbodiimide compound include N,N'-di-o-toluylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-di-2,6-dimethylphenylcarbodiimide, N,N'-bis(2,6-diisopropylphenyl)carbodiimide, N,N'-dioctyldecylcarbodiimide, N-triyl-N'-cyclohexylcarbodiimide, N,N'-di-2,2-di-t-butylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, N,N'-di-p-nitrophenylcarbodiimide, N,N'-di-p-aminophenylcarbodiimide, N,N'-di-p-hydroxyphenylcarbodiimide, N,N'-di-cyclohexylcarbodiimide, and N,N'-di-p-toluylcarbodiimide.

[0101] The adhesive for forming the second adhesive layer 12b may be, for example, a polyurethane adhesive containing a polyester polyol made of a hydrogenated dimer fatty acid and a diol, and a polyisocyanate. Examples of adhesives include polyurethane resins in which a bifunctional or higher isocyanate compound is reacted with a base resin 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 resin having epoxy groups. These are preferred from the viewpoint of the heat resistance of the exterior packaging material 10.

[0102] The thickness of the second adhesive layer 12b is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, processability, etc., the thickness of the second adhesive layer 12b is preferably 1 to 10 μm, and more preferably 2 to 7 μm.

[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 generally configured to include the steps of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, bonding the base material layer 11 and the barrier layer 13 together using the first adhesive layer 12a, further laminating a thermal adhesive resin layer 15 and a sealant layer 16 on the surface of the barrier layer 13 facing the corrosion prevention treatment layer 14b to produce a laminate, and, if necessary, aging the obtained laminate.

[0105] (Step of Laminating Anti-Corrosion Treatment Layers on Barrier Layer) This step is a step of forming anti-corrosion treatment layers 14a and 14b on the barrier layer 13. As described above, examples of the method for this include subjecting the barrier layer 13 to degreasing treatment, hydrothermal treatment, anodizing treatment, or chemical conversion treatment, or applying a coating agent having anti-corrosion properties.

[0106] Furthermore, when the corrosion prevention treatment layers 14a, 14b are multi-layered, for example, a coating liquid (coating agent) constituting the lower corrosion prevention treatment layer (barrier layer 13 side) may be applied to the barrier layer 13 and baked to form a first layer, and then a coating liquid (coating agent) constituting the upper corrosion prevention treatment layer may be applied to the first layer and baked to form a second layer.

[0107] The degreasing treatment may be carried out by spraying or immersion. The hydrothermal conversion treatment and anodizing treatment may be carried out by immersion. The chemical conversion treatment may be carried out by an appropriate method such as immersion, spraying, or coating, 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 for the barrier layer 13 may be performed on either one or both sides of the barrier layer 13 (e.g., metal foil), but in the case of one-side treatment, it is preferable to perform the above treatment on 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 It is preferable that the density is 0.010 to 0.100 g / m ２ It is more preferable that:

[0111] Furthermore, if dry curing is required, the dry curing can be performed so that the base material temperature is 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 barrier layer 13 (e.g., metal foil).

[0112] (Step of bonding substrate layer and barrier layer) This step is a step of bonding the barrier layer 13 provided with the corrosion prevention treatment layers 14a and 14b to the substrate layer 11 via the first adhesive layer 12a. The substrate layer 11 is bonded to the surface of the barrier layer 13 on the corrosion prevention treatment layer 14a side. As a bonding method, a technique such as dry lamination, non-solvent lamination or wet lamination is used, and the two layers (barrier layer 13 and substrate layer 11) are bonded together using the material that constitutes the first adhesive layer 12a described above. The first adhesive layer 12a has a dry coating amount preferably of 1 to 10 g / m ２ in the range of 2 to 7 g / m ２ The range is set as follows.

[0113] (Laminating Process of Thermal Adhesive Resin Layer and Sealant Layer) The laminating process of the thermal adhesive resin layer 15 and the sealant layer 16 is a process of forming the thermal adhesive resin layer 15 and the sealant layer 16 on the surface of the barrier layer 13 facing the corrosion prevention treatment layer 14b. Examples of the method include a method of sandwich laminating the thermal adhesive resin layer 15 with the corrosion prevention treatment layer 14b and the sealant layer 16 using an extrusion laminator. Furthermore, lamination can also be performed using a tandem lamination method or a co-extrusion method in which the thermal adhesive resin layer 15 and the sealant layer 16 are extruded. The thermal adhesive resin layer 15 is formed using a resin composition for forming the thermal adhesive resin layer containing the above-mentioned components of the thermal adhesive resin layer 15. The sealant layer 16 is formed using a resin composition for forming the sealant layer containing the above-mentioned components of the sealant layer 16. The laminate 17 of the thermal adhesive resin layer 15 and the sealant layer 16 has a hydrogen sulfide permeability coefficient of 1.1 x 10 －９ ~1.0 x 10 －８ [cc mm / cm ２ To achieve this, for example, the resins used for the polypropylene-based resin (A) and polyethylene-based resin (B) contained in the sealant layer 16 and the resin used for the thermal adhesive resin layer 15 may be appropriately selected in consideration of the crystallinity and melting point, and the resin composition may be appropriately set to adjust the hardness and softness of the thermal adhesive resin layer 15 and the sealant layer 16 so that they are balanced.

[0114] By the lamination process of the thermal adhesive resin layer 15 and the sealant layer 16, a laminate is obtained in which the substrate layer 11, the first adhesive layer 12a, the first corrosion prevention treatment layer 14a, the barrier layer 13, the second corrosion prevention treatment layer 14b, the thermal adhesive resin layer 15, and the sealant layer 16 are laminated in this order, as shown in FIG. 1 .

[0115] The thermal adhesive resin layer 15 may be formed by directly extruding, using an extrusion laminator, a material obtained by dry-blending the components of the resin composition for forming the thermal adhesive resin layer. Alternatively, the thermal adhesive resin layer 15 may be formed by extruding, using an extrusion laminator, a granulated product that has been previously melt-blended using a melt-kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer.

[0116] The sealant layer 16 may be laminated by directly extruding a material obtained by dry-blending the components of the resin composition for forming the sealant layer using an extrusion laminator. Alternatively, the thermal adhesive resin layer 15 and the sealant layer 16 may be laminated by a tandem lamination method or a co-extrusion method in which the 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 are extruded into the thermal adhesive resin layer 15 and the sealant layer 16 using an extrusion laminator. Alternatively, the thermal adhesive resin layer 15 and the sealant layer 16 may be laminated by a method in which the sealant layer 16 is previously formed as a cast film using the resin composition for forming the sealant layer, and then the sealant layer 16 is sandwich-laminated together with the thermal adhesive resin layer 15. The formation speed (processing speed) of the thermal adhesive resin layer 15 and the sealant layer 16 can be, for example, 80 m / min or more from the viewpoint of productivity of the exterior packaging material 10.

[0117] (Aging Treatment Step) The aging treatment step is a step of aging (curing) the laminate. By aging the laminate, it is possible to promote adhesion between the substrate layer 11, the first adhesive layer 12a, the first corrosion prevention treatment layer 14a, and the barrier layer 13, as well as adhesion between the barrier layer 13, the second corrosion prevention treatment layer 14b, the thermal adhesive resin layer 15, and the sealant layer 16. The aging temperature may be 80°C or higher, 100°C or higher, or 120°C or higher, and may be 140°C or lower, 150°C or lower, or 160°C or lower. The aging time may be 1 hour or longer, 2 hours or longer, or 3 hours or longer, and may be 24 hours or shorter, 48 hours or shorter, or 72 hours or shorter.

[0118] In this manner, the exterior packaging material 10 shown in FIG. 1 can be manufactured.

[0119] Next, a description will be given of an example of a method for manufacturing the exterior packaging material 20 for an electricity storage device shown in Fig. 2. Note that the method for manufacturing the exterior packaging material 20 is not limited to the following method.

[0120] The manufacturing method of the exterior packaging material 20 of this embodiment is generally configured to include the steps of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, bonding the base material layer 11 and the barrier layer 13 together using the first adhesive layer 12a, bonding the sealant layer 16 to the corrosion prevention treatment layer 14b side of the barrier layer 13 via the second adhesive layer 12b to obtain a laminate, and, if necessary, aging the obtained laminate. The steps up to the step of bonding the base material layer 11 and the barrier layer 13 together using the first adhesive layer 12a can be performed in the same manner as the manufacturing method of the exterior packaging material 10 described above. The step of aging the obtained laminate can be performed in the same manner as the manufacturing method of the exterior packaging material 10 described above.

[0121] (Laminating Step of Second Adhesive Layer and Sealant Layer) The laminating step of the second adhesive layer 12b and the sealant layer 16 is a step of obtaining a laminate by bonding the sealant layer 16 via the second adhesive layer 12b to the corrosion prevention treatment layer 14b side of the barrier layer 13. Examples of the bonding method include a wet process and dry lamination.

[0122] In the case of a wet process, a solution or dispersion of the adhesive constituting the second adhesive layer 12b is applied onto the corrosion prevention treatment layer 14b, the solvent is evaporated at a predetermined temperature to form a dry film, and after the dry film formation, a baking process is performed as necessary. Then, the sealant layer 16 is laminated. Various coating methods can be used. The preferred dry application amount of the second adhesive layer 12b is the same as that of the first adhesive layer 12a.

[0123] In this case, the sealant layer 16 can be produced by, for example, a melt extrusion molding machine using a resin composition for forming a sealant layer containing the above-mentioned polypropylene-based resin (A) and polyethylene-based resin (B). In the melt extrusion molding machine, the processing speed can be set to 80 m / min or more from the viewpoint of productivity of the packaging material 10.

[0124] The sealant layer 16 has a hydrogen sulfide permeability coefficient of 1.1×10 －９ ~1.0 x 10 －８ [cc mm / cm ２To achieve this, for example, the resins used for the polypropylene-based resin (A) and the polyethylene-based resin (B) contained in the sealant layer 16 may be appropriately selected in consideration of the crystallinity and melting point, and the resin contents in the polypropylene-based resin (A) and the polyethylene-based resin (B) may be appropriately set to adjust the hardness and softness of the sealant layer 16 so as to achieve a balance between them.

[0125] In this manner, the exterior packaging material 20 shown in FIG. 2 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. 4. FIG. 4 is a perspective view of the electricity storage device according to an embodiment of the present disclosure. As shown in FIG. 4, the electricity storage device 50 includes an electricity storage element 52 and an outer bag 54 that houses the electricity storage element 52. The electricity storage device 50 may further include two metal terminals (current extraction terminals) 53 that extend from the electricity storage element 52 and are used to extract current to the outside. Here, the outer bag 54 holds the metal terminals 53 between them. The outer bag 54 may also house the electricity storage element 52 in an airtight state.

[0127] The exterior bag 54 is formed using the exterior material 10. In the exterior material 10, the base material layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. As shown in FIG. 4 , the exterior bag 54 may be formed by folding one exterior material 10 in half and heat-sealing the peripheral edges so that the base material layer 11 is on the outer side of the electricity storage device 50 and the sealant layer 16 is on the inner side of the electricity storage device 50, or by stacking two exterior materials 10 and heat-sealing the peripheral edges. The metal terminal 53 is sandwiched by the exterior bag 54, which forms a container, with the sealant layer 16 on the inside. The metal terminal 53 may be sandwiched by the exterior materials 10 via a tab sealant.

[0128] According to the energy storage device 50, even if the outer casing material 10 is stretched when the energy storage element 52 expands and contracts in response to charging and discharging during operation of the energy storage device 50, the deterioration of the insulating properties of the outer casing bag 54 formed using the outer casing material 10 is suppressed, and the energy storage device 50 can have a longer lifespan.

[0129] The electricity storage element 52 has a positive electrode, a negative electrode, and an electrolyte. The electrolyte is disposed at least between the positive electrode and the negative electrode. The electrolyte may be a liquid electrolyte or a solid electrolyte. Examples of solid electrolytes include oxide-based solid electrolytes and sulfide-based solid electrolytes.

[0130] Metal terminal 53 is a part of the current collector that is taken out to the outside of exterior packaging material 10, and is made of a metal foil such as copper foil or aluminum foil. Note that in electricity storage device 50, exterior packaging material 20 may be used instead of exterior packaging material 10.

[0131] Specific examples of the electricity storage device 50 include secondary batteries such as all-solid-state batteries, lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries, electrochemical capacitors such as electric double layer capacitors, and semi-solid batteries. When the electricity storage device 50 is an all-solid-state battery, that is, when the electricity storage element 52 includes a solid electrolyte, the electricity storage element 52 is particularly prone to expansion and contraction, but even when the electricity storage element 52 expands and contracts, deterioration in the insulating properties of the exterior bag 54 is suppressed because deterioration in the insulating properties of the exterior bag 54 is suppressed, and the electricity storage device 50 has a longer lifespan.

[0132] The present disclosure will be specifically described below based on examples, but the present disclosure is not limited to the following examples.

[0133] [Materials Used] The materials used for the substrate layer, the adhesive for forming the first adhesive layer, the adhesive for forming the second adhesive layer, the material for forming the first corrosion prevention treatment layer and the material for forming the second corrosion prevention treatment layer, the barrier layer, the composition for forming the thermal adhesive resin layer, and the composition for forming the sealant layer are as follows.

[0134] <Base layer> PET: polyethylene terephthalate film (thickness 25 μm) with one side subjected to corona treatment

[0135] <Adhesive for Forming First Adhesive Layer> An adhesive (first adhesive) prepared by blending polyester polyol (manufactured by Showa Denko Materials K.K., product name: Teslac 2505-63, hydroxyl value: 7 to 11 mgKOH / g) and a nurate form of isophorone diisocyanate (manufactured by Mitsui Chemicals, Inc., product name: Takenate 600) so that the NCO / OH ratio was 20.0, and diluting the blend with ethyl acetate to a solids content of 26% by mass.

[0136] <Adhesive for forming second adhesive layer> An adhesive (second adhesive) in which 10 parts by mass (solid content ratio) of a polyisocyanate compound having an isocyanurate structure is blended with 100 parts by mass of an acid-modified polyolefin resin dissolved in toluene.

[0137] <Materials for forming first corrosion prevention treatment layer and materials for forming second corrosion prevention treatment layer> The materials for forming the first corrosion prevention treatment layer (substrate layer side) and the materials for forming the second corrosion prevention treatment layer (sealant layer side) are as follows (CL-1) and (CL-2). (CL-1): Sodium polyphosphate-stabilized cerium oxide sol adjusted to a solids concentration of 10% by mass using distilled water as a solvent. 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): Composition adjusted to a solids concentration of 5% by mass using distilled water as a solvent. In the above compositions, the ratio of polyallylamine (manufactured by Nitto Boseki Co., Ltd.) to polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation) was 90:10 (mass ratio).

[0138] <Barrier layer (thickness 40 μm)> Annealed and degreased soft aluminum foil (manufactured by Toyo Aluminum K.K., "8079 material")

[0139] <Composition for forming a thermal adhesive resin layer> A composition for forming a thermal adhesive resin layer obtained by mixing maleic anhydride-modified homopolypropylene and an ethylene-1-butene copolymer as a polyethylene-based resin in proportions of 80% by mass and 20% by mass, respectively.

[0140] <Resin composition for forming sealant layer> A resin composition for forming a sealant layer obtained by dry blending the polypropylene-based resin (A) and polyethylene-based resin (B) of the types shown in Table 2 or Table 3 to obtain the content shown in Table 2 or Table 3. The materials, melting points, and Mw / Mn of the polypropylene-based resin (A) and polyethylene-based resin (B) of the types shown in Table 2 or Table 3 are as shown in Table 1 below. In Tables 1 to 3 below, "PP" stands for "polypropylene," "PE" stands for "polyethylene," and LLDPE stands for "linear low-density polyethylene."

[0141] The melting peak temperature of the polypropylene resin (A) was measured by a differential scanning calorimeter in accordance with JIS K7121-1987. The Mw and Mn of the polyethylene resin (B) were determined in terms of polystyrene at a measurement temperature of 145°C using gel permeation chromatography in accordance with JIS K7252-1 and 4:2016.

[0142] [Preparation of Exterior Material] (Example 1) First, first and second corrosion prevention treatment layers were provided on both sides of the barrier layer by the following procedure. That is, (CL-1) was applied to both sides of the barrier layer in a dry coating amount of 70 mg / m ２ The 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 with (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 barrier layer.

[0143] Next, a substrate layer was attached to the first corrosion prevention treatment layer using a dry lamination technique with a first adhesive layer-forming adhesive. That is, the adhesive for forming the first adhesive layer was applied to the surface of the barrier layer facing the first corrosion prevention treatment layer so that the thickness after curing would be 4 μm, and the layer was dried by heating 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 first laminate (substrate layer / first adhesive layer / first corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer) was obtained.

[0144] Finally, a thermal adhesive resin layer and a sealant layer were laminated in this order on the second corrosion prevention treatment layer. That is, the first laminate was set on the unwinding section of an extrusion laminator. Then, a thermal adhesive resin layer and a sealant layer were laminated in this order on the second corrosion prevention treatment layer by co-extruding a composition for a thermal adhesive resin layer and a resin composition for forming a sealant layer from a T-die under processing conditions of 270 ° C and 80 m / min. In addition, the thicknesses of the thermal adhesive resin layer and the sealant layer were 20 μm and 60 μm, respectively, and the hydrogen sulfide permeability coefficient of the laminate consisting of the thermal adhesive resin layer and the sealant layer was set to the value shown in Table 2.

[0145] In this way, an exterior packaging material for an electricity storage device according to Example 1 (substrate layer / first adhesive layer / first corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer / thermal adhesive resin layer / sealant layer) was obtained.

[0146] Examples 2 to 9 and Comparative Examples 1 and 2 As the resin composition for forming a sealant layer, a resin composition for forming a sealant layer obtained by dry blending the polypropylene-based resin (A) and the polyethylene-based resin (B) shown in Table 2 so as to have the respective contents shown in Table 2 was used, and packaging materials for electricity storage devices according to Examples 2 to 9 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that the hydrogen sulfide permeability coefficient of the laminate consisting of the thermal adhesive resin layer and the sealant layer was adjusted to the value shown in Table 2.

[0147] (Examples 10 and 11 and Comparative Example 3) A first laminate (substrate layer / first adhesive layer / first corrosion prevention treatment layer / barrier layer / second corrosion prevention treatment layer) was obtained in the same manner as in Example 1. Next, an 80 μm thick sealant layer was attached to the second corrosion prevention treatment layer of the first laminate using a dry lamination technique with an adhesive for forming a second adhesive layer, and then aging was performed under conditions of 40°C and 96 hours. In this way, packaging materials for electrical storage devices according to Examples 10 and 11 and Comparative Example 3 were obtained. At this time, the sealant layer was prepared in advance using a T-die method using a sealant layer-forming resin composition obtained by dry blending the polypropylene-based resin (A) and the polyethylene-based resin (B) shown in Table 3 so as to have the respective contents shown in Table 2. The sealant layer was attached to the first laminate by applying the adhesive for forming the second adhesive layer onto the second corrosion prevention treatment layer so that the thickness after heating would be 3 μm, heating the second adhesive layer at 100° C. for 1 minute, and then laminating the second adhesive layer and the sealant layer. The hydrogen sulfide permeability coefficient of the sealant layer was set to the value shown in Table 3.

[0148] [Measurement of Hydrogen Sulfide Permeability Coefficient] (1) Hydrogen Sulfide Permeability Coefficient of Laminate of Thermal Adhesive Resin Layer and Sealant Layer A laminate of a thermal adhesive resin layer and a sealant layer was obtained by co-extrusion of a composition for forming a thermal adhesive resin layer and a resin composition for forming a sealant layer through a T-die at a processing condition of 270°C and 80 m / min. The thicknesses of the thermal adhesive resin layer and the sealant layer were 20 μm and 60 μm, respectively. The hydrogen sulfide permeability coefficient of the laminate was then measured according to the method for measuring the hydrogen sulfide permeability coefficient of a laminate described above. (2) Hydrogen Sulfide Permeability Coefficient of Laminate of Sealant Layer A sealant layer was obtained by extruding a resin composition for forming a sealant layer through a T-die at a processing condition of 270°C and 80 m / min. The thickness of the sealant layer was 80 μm. The hydrogen sulfide permeability coefficient of the sealant layer was then measured according to the method for measuring the hydrogen sulfide permeability coefficient of a laminate described above.

[0149] [Evaluation of Insulation Properties] The insulation properties of the packaging materials of the Examples and Comparative Examples were evaluated. (1) Sample Preparation First, rectangular sheets measuring 50 mm in length and 30 mm in width were cut out from the packaging materials obtained in the Examples and Comparative Examples. Next, using a tensile tester (manufactured by Shimadzu Corporation), the sheets were stretched in the longitudinal direction at a speed of 5 mm / min until the displacement amount reached 10%. The stretched sheets were used as measurement samples. (2) Insulation Properties Evaluation Test Only a portion of the substrate layer and the first adhesive layer of the measurement sample obtained as described above was scraped off with sandpaper to expose the aluminum foil barrier layer. Next, the measurement sample was placed on a flat surface with the substrate layer facing the flat surface and the sealant layer facing away from the flat surface. Tap water was then dropped on the center of the surface of the sealant layer of the measurement sample, and a 95 g weight was placed on the center of the drop. Next, the measurement sample was clamped with alligator clips so that it was in contact with the barrier layer but not in contact with the weight or the drop on the laminate. The weight was then connected to the negative terminal of a power supply, and the alligator clip was connected to the positive terminal of the power supply. Voltages of 4 kV, 5 kV, and 6 kV were applied, and the current values ​​were measured. The insulation properties were evaluated based on the applied voltage, the measured current values, and the following evaluation criteria. In this way, the insulation properties after stretching were evaluated. Measurement samples were prepared in the same manner as above, except that stretching using a tensile tester was not performed, and the insulation properties (insulation properties before stretching) of these measurement samples were evaluated. The results are shown in Table 4.

[0150] (Insulation evaluation criteria) A: Current value is less than 5 mA when a DC voltage of 6 kV is applied. B: Current value is 5 mA or more when a DC voltage of 6 kV is applied, and current value is less than 5 mA when a DC voltage of 5 kV is applied. C: Current value is 5 mA or more when a DC voltage of 5 kV is applied, and current value is less than 5 mA when a DC voltage of 4 kV is applied. D: Current value is 5 mA or more when a DC voltage of 4 kV is applied.

[0151]

[0152] From the results shown in Table 4, the evaluation of the insulating properties after stretching was "A" before stretching, whereas Examples 1 to 11 were "A" to "C", while Comparative Examples 1 to 3 were "D".

[0153] From the above, it was confirmed that the packaging material for an electricity storage device according to the present disclosure can suppress deterioration in insulation properties due to stretching.

[0154] The outline of the present disclosure is as follows: [1] A laminate including a base layer, a barrier layer, an adhesive layer, and a sealant layer in this order, wherein the adhesive layer is a thermal adhesive resin layer or an adhesive layer, and when the adhesive layer is the thermal adhesive resin layer, the hydrogen sulfide permeability coefficient of the laminate of the thermal adhesive resin layer and the sealant layer is 1.1 × 10 －９ cc mm / cm ２ ・sec・cmHg or more, 1.0×10 －８ cc mm / cm ２ sec cmHg, and when the adhesive layer is an adhesive layer, the hydrogen sulfide permeability coefficient of the sealant layer is less than 1.1 x 10 －９ cc mm / cm ２ ・sec・cmHg or more, 1.0×10 －８ cc mm / cm ２.sec·cmHg or less. [2] The packaging material for an electricity storage device according to [1], wherein the sealant layer comprises a polypropylene-based resin containing at least one of homopolypropylene and block polypropylene, and a polyethylene-based resin, the polyethylene-based resin having at least one melting peak in the range of 60°C to 105°C. [3] The packaging material for an electricity storage device according to [1] or [2], wherein the ratio (Mw / Mn) of the weight-average molecular weight Mw to the number-average molecular weight Mn of the polyethylene-based resin is 1.2 or more and 5.0 or less. [4] The packaging material for an electricity storage device according to [1], wherein the sealant layer comprises a polypropylene-based resin containing at least one of homopolypropylene and block polypropylene, and the content of the polypropylene-based resin in the sealant layer is 50 to 95 mass%. [5] The packaging material for an electricity storage device according to any one of [1] to [4], wherein the adhesive layer is the thermal adhesive resin layer, the thermal adhesive resin layer contains a polypropylene-based resin, and the content of the polypropylene-based resin in the thermal adhesive resin layer is 50 to 95 mass%. [6] The packaging material for an electricity storage device according to [1], wherein the sealant layer contains a polypropylene-based resin including homopolypropylene and a polyethylene-based resin, and the ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn (Mw / Mn) of the polyethylene-based resin is 1.2 or more and 5.0 or less. [7] The packaging material for an electricity storage device according to [1] to [6], wherein when the adhesive layer is the thermal adhesive resin layer, the total thickness of the laminate of the thermal adhesive resin layer and the sealant layer is 25 to 150 μm, and when the adhesive layer is the adhesive layer, the thickness of the sealant layer is 25 to 150 μm. [8] The packaging material for an electricity storage device according to any one of [1] to [7], wherein the electricity storage device is an all-solid-state battery. [9] An electricity storage device comprising: an electricity storage element; and an outer bag that houses the electricity storage element, wherein the outer bag is formed using the exterior packaging material for an electricity storage device according to any one of [1] to [8].

[10] The electricity storage device according to [9], which is an all-solid-state battery.

[0155] According to the packaging material for an electricity storage device of the present disclosure, deterioration in insulating properties due to stretching can be suppressed, and therefore the present disclosure is useful for electricity storage devices such as all-solid-state batteries.

[0156] DESCRIPTION OF SYMBOLS 10, 20...outer packaging material for electricity storage device, 11...substrate layer, 13...barrier layer, 15...thermoadhesive resin layer (adhesive layer), 16...sealant layer, 17...laminated body, 12b...second adhesive layer (adhesive layer), 50...electricity storage device (all-solid-state battery), 52...electricity storage element, 54...outer packaging bag

Claims

1. A laminate comprising a base layer, a barrier layer, an adhesive layer, and a sealant layer in this order, the adhesive layer being a thermal adhesive resin layer or an adhesive layer, and when the adhesive layer is the thermal adhesive resin layer, the hydrogen sulfide permeability coefficient of the laminate of the thermal adhesive resin layer and the sealant layer is 1.1 x 10 －９ cc mm / cm ２ ・sec・cmHg or more, 1.0×10 －８ cc mm / cm ２ sec cmHg or less, and when the adhesive layer is an adhesive layer, the hydrogen sulfide permeability coefficient of the sealant layer is less than 1.1 x 10 －９ cc mm / cm ２ ・sec・cmHg or more, 1.0×10 －８ cc mm / cm ２ An exterior material for an electricity storage device, which has a resistance to heat transfer of less than sec·cmHg.

2. The exterior packaging material for an electricity storage device according to claim 1, wherein the sealant layer comprises a polypropylene-based resin containing at least one of homopolypropylene and block polypropylene, and a polyethylene-based resin, and the polyethylene-based resin has at least one melting peak in the range of 60°C or higher and 105°C or lower.

3. The exterior material for an electricity storage device according to claim 2, wherein the ratio (Mw / Mn) of the weight average molecular weight Mw to the number average molecular weight Mn of the polyethylene resin is 1.2 or more and 5.0 or less.

4. The exterior packaging material for an electricity storage device according to claim 1, wherein the sealant layer contains a polypropylene-based resin including at least one of homopolypropylene and block polypropylene, and the content of the polypropylene-based resin in the sealant layer is 50 to 95 mass %.

5. The exterior packaging material for an electricity storage device according to claim 4, wherein the adhesive layer is a thermal adhesive resin layer, the thermal adhesive resin layer contains a polypropylene-based resin, and the content of the polypropylene-based resin in the thermal adhesive resin layer is 30 to 100 mass %.

6. The exterior material for an electricity storage device according to claim 1, wherein the sealant layer comprises a polypropylene-based resin including homopolypropylene and a polyethylene-based resin, and the ratio (Mw / Mn) of the weight-average molecular weight Mw to the number-average molecular weight Mn of the polyethylene-based resin is 1.2 or more and 5.0 or less.

7. The exterior packaging material for an electricity storage device according to claim 1, wherein, when the adhesive layer is the thermal adhesive resin layer, the total thickness of the laminate of the thermal adhesive resin layer and the sealant layer is 25 to 150 μm, and when the adhesive layer is the adhesive layer, the thickness of the sealant layer is 25 to 150 μm.

8. The exterior packaging material for an electricity storage device according to any one of claims 1 to 7, wherein the electricity storage device is an all-solid-state battery.

9. An electricity storage device comprising: an electricity storage element; and an outer bag that houses the electricity storage element, wherein the outer bag is formed using the outer casing material for an electricity storage device according to any one of claims 1 to 7.

10. The electricity storage device according to claim 9, which is an all-solid-state battery.

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