Exterior member for power storage device, power storage device, and method for manufacturing power storage device

Abstract

An exterior film for a power storage device comprises, in order from the outer side, at least a base material layer, a barrier layer, and a laminate provided with a heat-fusible resin layer. The barrier layer contains at least one type of recycled material composed of any one of an aluminum alloy, stainless steel, titanium steel, and a steel sheet.

Description

Exterior member for power storage device, power storage device, and method for manufacturing power storage device

[0001] The present invention relates to an exterior member for an electricity storage device, an electricity storage device including the exterior member for an electricity storage device, and a method for manufacturing the electricity storage device.

[0002] Japanese Patent No. 4509242 (Patent Document 1) discloses a secondary battery as an example of an electricity storage device. In this secondary battery, an electrode assembly is sealed in a pouch made of a laminate film. The laminate film includes a water vapor impermeable layer as an example of a barrier layer for preventing water vapor from penetrating into the pouch. The water vapor impermeable layer is made of a metal foil such as aluminum.

[0003] Patent No. 4509242

[0004] From the viewpoint of protecting the global environment, it is preferable that electricity storage devices are manufactured in an energy-saving manner. In this respect, there is still room for improvement in the secondary battery.

[0005] An object of the present invention is to provide an exterior member for an electricity storage device that can contribute to energy conservation, an electricity storage device including this exterior member for an electricity storage device, and a method for manufacturing this electricity storage device.

[0006] An exterior member for an electricity storage device according to a first aspect of the present invention is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, and the barrier layer contains at least one recycled material made of any of aluminum alloy, stainless steel, titanium steel, and steel plate.

[0007] An electricity storage device according to a second aspect of the present invention includes an exterior member for an electricity storage device and an electrode body packaged in the exterior member for an electricity storage device, wherein the exterior member for an electricity storage device is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, and the barrier layer includes at least one recycled material made of any of aluminum alloy, stainless steel, titanium steel, and steel plate.

[0008] The electric storage device according to a third aspect of the present invention is the electric storage device according to the second aspect, and includes a first sealing portion sealed by joining facing surfaces of the outer casing member for the electric storage device together while the electrode body is wrapped in the outer casing member for the electric storage device.

[0009] An electricity storage device according to a fourth aspect of the present invention is the electricity storage device according to the second or third aspect, further including a lid body that seals the electrode body together with the exterior member for the electricity storage device, and a second sealing portion in which the lid body and the exterior member for the electricity storage device are joined.

[0010] An electricity storage device according to a fifth aspect of the present invention is the electricity storage device according to any one of the second to fourth aspects, wherein the exterior member for the electricity storage device includes a first exterior member and a second exterior member, and at least one of the first exterior member and the second exterior member has a recess formed therein to accommodate the electrode body.

[0011] A manufacturing method for an electricity storage device according to a sixth aspect of the present invention is a manufacturing method for an electricity storage device according to any one of the second to fifth aspects, and includes a step of manufacturing an exterior member for an electricity storage device composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, and the barrier layer contains at least one kind of recycled material made of any one of aluminum alloy, stainless steel, titanium steel, and steel plate.

[0012] The exterior member for an electricity storage device, the electricity storage device, and the method for manufacturing an electricity storage device according to the present invention can contribute to energy conservation.

[0013] 1B is a perspective view schematically showing an electricity storage device according to a first embodiment. FIG. 1C is a cross-sectional view showing an example of a layer configuration of the exterior member of FIG. 1A. FIG. 1D is a plan view schematically showing an electricity storage device. FIG. 1E is a side view schematically showing an electricity storage device. FIG. 1F is a view showing from a side a state in which an exterior member is wrapped around an electrode body during manufacturing of the electricity storage device according to the first embodiment. FIG. 1G is a view showing from below a state in which an exterior member is wrapped around an electrode body during manufacturing of the electricity storage device according to the first embodiment. FIG. 1H is a view schematically showing a part of a cross section taken along VI-VI of FIG. 2. FIG. 1I is a view for explaining a method of forming a second sealing portion. FIG. 1J is a flowchart showing an example of a manufacturing procedure for the electricity storage device according to the first embodiment. FIG. 1J is a side view schematically showing an electricity storage device. FIG. 1I is a perspective view schematically showing a lid. FIG. 1F is a view showing a first example in which the lid and the electrode terminals are integrally formed. FIG. 1G is a view showing a second example in which the lid and the electrode terminals are integrally formed. FIG. 1H is a flowchart showing an example of a manufacturing procedure for the electricity storage device according to the second embodiment. 24 is a diagram showing from a side a state in which an exterior member is wrapped around an electrode body in embodiment 3. FIG. 25 is a diagram showing from below a state in which an exterior member is wrapped around an electrode body and a lid body is attached to the exterior member in embodiment 3. FIG. 26 is a flowchart showing an example of a manufacturing procedure for an electricity storage device according to embodiment 3. FIG. 27 is a plan view schematically showing an electricity storage device according to embodiment 4. FIG. 28 is a side view schematically showing an electricity storage device according to embodiment 4. FIG. 29 is a diagram showing from a side a state in which an exterior member is wrapped around an electrode body in a modified example. FIG. 29 is a perspective view schematically showing an electricity storage device of a modified example. FIG. 29 is a perspective view schematically showing a lid body of a modified example and electrode terminals attached to the lid body. FIG. 29 is a diagram showing an insertion step of a manufacturing method for an electricity storage device according to a modified example. FIG. 29 is a perspective view schematically showing a lid body of a modified example and electrode terminals attached to the lid body. FIG. 29 is a perspective view schematically showing an electricity storage device with the lid body of FIG. 23 attached. FIG. 29 is a front view schematically showing a lid body of another modified example. FIG. 29 is a front view schematically showing a lid body of yet another modified example. FIG. 29 is a plan view schematically showing an electricity storage device of another modified example.30B is a diagram showing an example of a manufacturing process for an electricity storage device that is another modified example of the electricity storage device of FIG. 30A. FIG. 30C is a perspective view of an electricity storage device manufactured through the manufacturing process of FIG. 30B. FIG. 30D is a perspective view of an electricity storage device that is yet another modified example of the electricity storage device of FIG. 30A. FIG. 30E is a diagram showing, from the side, a state in which an exterior member is wrapped around an electrode body during the manufacturing of an electricity storage device that is another modified example. FIG. 31 is an enlarged view of the X portion of FIG. 31. FIG. 31 is a cross-sectional view of an electricity storage device that is a modified example. FIG. 31F is a cross-sectional view of an electricity storage device that is a modified example.

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. In the present embodiment, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the notation 2 to 15 mm means 2 mm or more and 15 mm or less. In the numerical ranges described in stages in the present embodiment, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, separately described upper and lower limits, upper and lower limits, or lower and lower limits may each be combined to form a numerical range.

[0015] [1. First Embodiment] <1-1. Configuration of Electricity Storage Device> Fig. 1A is a perspective view that schematically shows an electricity storage device 10 according to the first embodiment. Fig. 2 is a plan view that schematically shows the electricity storage device 10. Fig. 3 is a side view that schematically shows the electricity storage device 10. In each of Figs. 2 and 3, the direction of arrow UD indicates the thickness direction of the electricity storage device 10, and the direction of arrow LR indicates the width direction of the electricity storage device 10. Furthermore, the direction of arrow FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UDLRFB are common to the subsequent figures.

[0016] 1A, 1B, 2, and 3, the electricity storage device 10 includes an electrode body 200, an exterior body 100, and a plurality (two) of electrode terminals 300. The electrode body 200 includes electrodes (positive and negative electrodes) and separators that constitute an electricity storage member such as a lithium ion battery, a capacitor, or an all-solid-state battery. The shape of the electrode body 200 is a substantially rectangular parallelepiped. Note that the term "substantially rectangular parallelepiped" refers not only to a perfect rectangular parallelepiped, but also to a solid that can be regarded as a rectangular parallelepiped by, for example, modifying the shape of a portion of its outer surface.

[0017] The electrode terminal 300 is a metal terminal used for inputting and outputting power in the electrode body 200. One end of the electrode terminal 300 is electrically connected to an electrode (positive electrode or negative electrode) included in the electrode body 200, and the other end protrudes outward from the edge of the exterior body 100.

[0018] The metal material constituting the electrode terminal 300 is, for example, aluminum, nickel, copper, etc. For example, when the electrode body 200 is a lithium ion battery, the electrode terminal 300 connected to the positive electrode is usually made of aluminum, etc., and the electrode terminal 300 connected to the negative electrode is usually made of copper, nickel, etc.

[0019] 1B (hereinafter referred to as "exterior member 101"), and seals the electrode assembly 200. In the electricity storage device 10 of the present embodiment, the exterior member 101 is wrapped around the electrode assembly 200 and the open portion is sealed, thereby forming the exterior member 101.

[0020] The exterior body 100 seals the electrode body 200 by wrapping the exterior member 101 around the electrode body 200, and therefore can easily seal the electrode body 200 regardless of the thickness of the electrode body 200. Note that in order to reduce dead space between the electrode body 200 and the exterior member 101 in order to improve the volumetric energy density of the power storage device 10, it is preferable that the exterior member 101 be wrapped so as to contact the outer surface of the electrode body 200. Furthermore, in an all-solid-state battery, it is necessary to apply high pressure uniformly from the outer surface of the battery in order to demonstrate battery performance, and therefore it is necessary to eliminate the space between the electrode body 200 and the exterior member 101. Therefore, it is preferable that the exterior member 101 be wrapped so as to contact the outer surface of the electrode body 200. Note that the exterior body 100 may be configured by forming a housing portion (recess) in the exterior member 101 through cold forming and housing the electrode body 200 in the housing portion.

[0021] 1B is a cross-sectional view showing an example of the layer structure of the exterior member 101. The exterior member 101 is, for example, a laminate 101Z (laminate film) having, in this order from the outside, at least a base layer 101A, a barrier layer 101B, and a thermally adhesive resin layer 101C.

[0022] The base material layer 101A included in the exterior member 101 is a layer that imparts heat resistance to the exterior member 101 and suppresses the occurrence of pinholes that may occur during processing or distribution. The base material layer 101A is configured to include, for example, at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, by including at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer in the base material layer 101A, the barrier layer 101B can be protected during processing of the exterior member 101, and breakage of the exterior member 101 can be suppressed. Furthermore, from the viewpoint of increasing the tensile elongation of the exterior member 101, the stretched polyester resin layer is preferably a biaxially stretched polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially stretched polyamide resin layer. Furthermore, from the viewpoint of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The base layer 101A may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. From the viewpoint of film strength, the thickness of the base layer 101A is preferably, for example, 5 to 300 μm, and more preferably 20 to 150 μm.

[0023] In the exterior member 101, the barrier layer 101B is a layer that at least suppresses the penetration of moisture. From the viewpoint of energy saving, the barrier layer 101B of the exterior member 101 in this embodiment contains at least one type of recycled material made of any of aluminum alloy, stainless steel, titanium steel, and steel plate. The barrier layer 101B may be provided in multiple layers. The aluminum alloy and stainless steel can also be used as, for example, metal foil. The barrier layer 101B may be made only of recycled material. From the viewpoint of improving the formability of the exterior member 101, the barrier layer 101B may be made of a mixed material of recycled material and virgin raw material.

[0024] Recycled materials made of aluminum alloys, stainless steels, titanium steels, or steel plates can be obtained by known methods. For example, recycled aluminum alloy materials can be obtained by the manufacturing method described in WO 2022 / 092231.

[0025] From the viewpoint of improving the formability or conformability of the exterior member 101, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of further improving the formability or conformability, an aluminum alloy foil containing iron is preferable. In the aluminum alloy foil containing iron (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. By having an iron content of 0.1% by mass or more, an exterior material for an electricity storage device with better formability can be obtained. By having an iron content of 9.0% by mass or less, an exterior material for an electricity storage device with better flexibility can be obtained. Examples of soft aluminum alloy foils include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, and the like may also be added as needed. Softening can be achieved by annealing or the like. From the perspective of improving the mechanical strength of the exterior member 101, the aluminum alloy foil is preferably a hard aluminum alloy foil made of, for example, a work-hardened aluminum alloy. Examples of hard aluminum alloy foils include aluminum alloy foils having a composition defined in JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14. From the viewpoint of improving the mechanical strength of the exterior member 101, the aluminum alloy foil is preferably an aluminum alloy foil containing magnesium. In the aluminum alloy foil containing magnesium (100% by mass), the magnesium content is preferably 0.2 to 5.6% by mass, and more preferably 0.2 to 3.0% by mass.Examples of aluminum alloy foils containing magnesium include aluminum alloy foils having compositions defined in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JIS H4000:2017 A5052P-O.

[0026] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. From the viewpoint of providing an exterior material for an electricity storage device that has excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0027] Specific examples of austenitic stainless steels that form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0028] In the case of a metal foil, the thickness of the barrier layer 101B should be sufficient to at least function as a barrier layer that prevents moisture penetration, and may be, for example, approximately 5 to 200 μm. The thickness of the barrier layer 101B is preferably approximately 85 μm or less, more preferably approximately 50 μm or less, even more preferably approximately 40 μm or less, and particularly preferably approximately 35 μm or less. The thickness of the barrier layer 101B is preferably approximately 9.0 μm or more, more preferably approximately 20 μm or more, and more preferably approximately 25 μm or more. Furthermore, preferred ranges for the thickness of the barrier layer 101B include about 9.0 to 85 μm, about 9.0 to 50 μm, about 9.0 to 40 μm, about 9.0 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 101B is made of aluminum alloy foil, the above-mentioned ranges are particularly preferred. From the viewpoint of imparting high moldability and high rigidity to the exterior member 101, the thickness of the barrier layer 101B is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and even more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, and even more preferably about 70 μm or less. Preferred ranges are approximately 35 to 200 μm, approximately 35 to 85 μm, approximately 35 to 75 μm, approximately 35 to 70 μm, approximately 45 to 200 μm, approximately 45 to 85 μm, approximately 45 to 75 μm, approximately 45 to 70 μm, approximately 50 to 200 μm, approximately 50 to 85 μm, approximately 50 to 75 μm, approximately 50 to 70 μm, approximately 55 to 200 μm, approximately 55 to 85 μm, approximately 55 to 75 μm, and approximately 55 to 70 μm. The high formability of the exterior member 101 facilitates deep drawing, which can contribute to increasing the capacity of the electricity storage device. Furthermore, while increasing the capacity of the electricity storage device increases the weight of the electricity storage device, increasing the rigidity of the exterior member 101 can contribute to high sealing performance of the electricity storage device.In particular, when the barrier layer 101B is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred thickness ranges for the stainless steel foil include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0029] Furthermore, when the barrier layer 101B is a metal foil, it is preferable that a corrosion-resistant coating be provided on at least the surface opposite the substrate layer 101A to prevent dissolution and corrosion. The barrier layer 101B may be provided with a corrosion-resistant coating on both sides. Here, the corrosion-resistant coating refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) on the surface of the barrier layer 101B by, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment such as applying a coating agent. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the barrier layer 101B (acid-resistant coating), a coating that improves the alkali resistance of the barrier layer 101B (alkali-resistant coating), or the like. The corrosion-resistant coating may be formed by one type of treatment or a combination of two or more types. Furthermore, the barrier layer 101B may be formed not only as a single layer but also as a multi-layer. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the surface of the metal foil is dissolved with a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may also be included in the definition of chemical conversion treatment. Furthermore, when the barrier layer 101B has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 101B.

[0030] The corrosion-resistant coating prevents delamination between the barrier layer 101B (e.g., aluminum alloy foil) and the substrate layer 101A during molding of the exterior member 101, and prevents dissolution and corrosion of the surface of the barrier layer 101B due to hydrogen fluoride produced by a reaction between an electrolyte and water, particularly when the barrier layer 101B is an aluminum alloy foil, dissolution and corrosion of aluminum oxide present on the surface of the barrier layer 101B. The corrosion-resistant coating also improves the adhesiveness (wettability) of the surface of the barrier layer 101B, thereby preventing delamination between the substrate layer 101A and the barrier layer 101B during heat sealing and between the substrate layer 101A and the barrier layer 101B during molding of the exterior member 101.

[0031] The thermally adhesive resin layer 101C included in the exterior member 101 is a layer that provides heat-sealing properties to the exterior member 101. Examples of the thermally adhesive resin layer 101C include a resin film made of a polyolefin resin or an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride. The thickness of the thermally adhesive resin layer 101C is not particularly limited as long as it can heat-seal the layers 101C to each other and function to seal the electrode body 200, but examples of the thickness include approximately 100 μm or less, preferably approximately 85 μm or less, and more preferably approximately 15 to 85 μm.

[0032] If the heat-sealable resin layer 101C is too hard, when the roll material or the exterior member 101 is bagged into the exterior body 100 by the device, it may slip at the contact point with the device and may not be transported properly. Furthermore, if the exterior member 101 is scratched by the friction, the heat-sealable resin layer 101C will be damaged. Since damage to the heat-sealable resin layer 101C may reduce the heat seal strength, it is preferable that the heat-sealable resin layer have a moderate slipperiness. Therefore, when a non-slip or non-slip material is used as the material constituting the heat-sealable resin layer 101C, it is preferable to add a lubricant from the viewpoint of transportability.

[0033] Furthermore, from the viewpoint of contamination resistance and processability, the thermally adhesive resin layer 101C preferably has a tensile modulus of elasticity measured in accordance with JIS K7161: 2014 in the range of 500 MPa to 1000 MPa. A more preferred range for the tensile modulus of elasticity of the thermally adhesive resin layer 101C is 500 MPa to 800 MPa, an even more preferred range is 500 MPa to 750 MPa, an even more preferred range is 500 MPa to 700 MPa, and an even more preferred range is 510 MPa to 700 MPa.

[0034] Having the thermally adhesive resin layer 101C have a tensile modulus of 500 MPa or more effectively prevents contamination of the device during molding and transportation of the outer casing 100. That is, having the thermally adhesive resin layer 101C have a tensile modulus of 500 MPa or more makes it difficult for the lubricant located on the surface of the thermally adhesive resin layer 101C to be scraped off by the device, etc., and therefore the lubricant located on the surface portion of the thermally adhesive resin layer 101C is less likely to transfer to the device, etc., effectively preventing contamination of the device, etc. Furthermore, having the thermally adhesive resin layer 101C have a tensile modulus of 1000 MPa or less ensures high sealing strength through heat fusion. That is, having the thermally adhesive resin layer 101C have a tensile modulus of 1000 MPa or less ensures that the thermally adhesive resin layer 101C is less likely to become brittle, thereby ensuring high sealing strength through heat fusion. If the tensile modulus of the heat-sealable resin layer 101C exceeds 1000 MPa, the heat-sealable resin layer 101C becomes brittle and easily peels off from the barrier layer 101B laminated thereto via an adhesive layer, resulting in reduced seal strength. Furthermore, stretching at the folded portion during molding of the exterior body 100 can cause whitening or cracking in the stretched portion, potentially resulting in reduced battery performance. Furthermore, if the tensile modulus of the heat-sealable resin layer 101C exceeds 1000 MPa, extrudability decreases, resulting in reduced productivity. Therefore, in the exterior member 101 of the power storage device 10 of this embodiment, by setting the tensile modulus of the heat-sealable resin layer 101C to a range of 500 to 1000 MPa, the effects of suppressing contamination of the device and improving the seal strength due to heat fusion are optimally exhibited. The tensile modulus of the heat-sealable resin layer 101C can be adjusted by adjusting the molecular weight, melt mass flow rate (MFR), etc., of the resin constituting the heat-sealable resin layer 101C.

[0035] Furthermore, when the work of butting together the sealed portions for pillow sealing and the work of folding are called "processing" when manufacturing the exterior body 100, the same problems as described above occur during this processing. Since the exterior member 101 is particularly susceptible to damage during processing, solving the above problems is important. Setting the tensile modulus of the heat-fusible resin layer 101C to be in the range of 500 MPa or more and 1000 MPa or less allows for good processing.

[0036] The exterior member 101 preferably has one or more layers having a buffer function (hereinafter referred to as "buffer layer") outside the heat-sealable resin layer 101C (upper side in FIG. 1B ), more preferably outside the barrier layer 101B. The buffer layer may be laminated on the outside of the base material layer 101A, or the base material layer 101A may also function as a buffer layer. When the exterior member 101 has multiple buffer layers, the multiple buffer layers may be adjacent to each other, or may be laminated with the base material layer 101A, the barrier layer 101B, or the like interposed therebetween.

[0037] The material constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. Examples of the material having cushioning properties include rubber, nonwoven fabric, and foam sheet. Examples of rubber include natural rubber, fluororubber, and silicone rubber. The rubber hardness is preferably about 20 to 90. The material constituting the nonwoven fabric is preferably a material having excellent heat resistance. When the buffer layer is made of nonwoven fabric, the lower limit of the thickness of the buffer layer is preferably 100 μm, more preferably 200 μm, and even more preferably 1000 μm. When the buffer layer is made of nonwoven fabric, the upper limit of the thickness of the buffer layer is preferably 5000 μm, and even more preferably 3000 μm. The thickness of the buffer layer is preferably in the range of 100 μm to 5000 μm, 100 μm to 3000 μm, 200 μm to 5000 μm, 200 μm to 3000 μm, 1000 μm to 5000 μm, or 1000 μm to 3000 μm, with the most preferred range being 1000 μm to 3000 μm.

[0038] When the buffer layer is made of rubber, the lower limit of the thickness of the buffer layer is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the thickness of the buffer layer is preferably 10 mm, more preferably 5 mm, and even more preferably 2 mm. When the buffer layer is made of rubber, the preferred range of the thickness of the buffer layer is 0.5 mm to 10 mm, 0.5 mm to 5 mm, or 0.5 mm to 2 mm.

[0039] When the exterior member 101 has a buffer layer, the buffer layer functions as a cushion, thereby preventing the exterior member 101 from being damaged by impact when the energy storage device 10 is dropped or by handling during manufacturing of the energy storage device 10.

[0040] In the exterior body 100 of the present embodiment, a deep housing portion can be formed in the exterior member 101 through cold forming, which increases the weight of the electrode assembly 200 and increases the susceptibility to attacks on the exterior body 100 due to impacts, etc. For this reason, in the present embodiment, when the thickness of the exterior member 101 is 195 μm or less and the thickness of the barrier layer 101B is within the range of 20 to 85 μm, the puncture strength when pierced from the base layer 101A side of the exterior member 101, as measured by a method conforming to the provisions of JIS Z1707:1997, is preferably 30 N or more. Preferred ranges of the puncture strength include, for example, approximately 30 to 45 N, approximately 30 to 40 N, approximately 35 to 45 N, and approximately 35 to 40 N. The puncture strength of the exterior member 101 is measured as follows.

[0041] The puncture strength from the base layer 101A side of the exterior member 101 is measured according to the method specified in JIS Z1707:1997. Specifically, in a measurement environment of 23±2°C and relative humidity (50±5%), a test specimen is fixed using a 115 mm diameter table with a 15 mm diameter opening in the center and a pressure plate, and a semicircular needle with a diameter of 1.0 mm and a tip radius of 0.5 mm is pierced at a rate of 50±5 mm per minute, and the maximum stress until the needle penetrates is measured. Five test specimens are measured, and the average value is calculated. If there are not enough test specimens to measure five, the number of measurable specimens is measured and the average value is calculated. The puncture strength measurement device used is a ZP-500N (force gauge) and MX2-500N (measurement stand) manufactured by Imada Co., Ltd.

[0042] In the electricity storage device 10 of the present embodiment, the weight of the electrode assembly 200 increases, which tends to cause friction between the electricity storage devices 10 themselves, friction between the electricity storage device 10 and peripheral components, and friction during transportation of the electricity storage device 10. Therefore, in the present embodiment, in addition to good ink fixation (good printing characteristics) on the surface of the exterior member 101 facing the base material layer 101A, it is preferable that the fixed ink is not easily erased. From this perspective, the exterior member 101 of the present embodiment preferably has a contact angle of 80° or less on the surface facing the base material layer 101A. That is, when the base material layer 101A constitutes the outermost surface of the exterior member 101, the contact angle of the surface of the base material layer 101A is 80° or less. Furthermore, when a coating layer is provided on the outside of the base material layer 101A, the contact angle of the surface of the coating layer is 80° or less. In this embodiment, the contact angle of the surface of the exterior member 101 on the side of the base material layer 101A is 80° or less, so ink is less likely to be repelled on the surface on the side of the base material layer 101A, resulting in excellent printing characteristics and less likely to cause the fixed ink to disappear. In particular, when ink is printed by pad printing on an exterior member 101 in which a lubricant is present on the surface on the side of the base material layer 101A to enhance formability, the ink may be repelled by the surface on the side of the base material layer 101A, resulting in printing defects. However, even in such cases, the exterior member 101 of the electricity storage device 10 of this embodiment has a contact angle of 80° or less on the surface on the side of the base material layer 101A, so ink is less likely to be repelled, making it particularly suitable as an exterior member 101 on which printing, etc., is formed on the surface of the base material layer 101A by pad printing.

[0043] In the present embodiment, from the viewpoint of improving printability and making it difficult for the fixed ink to disappear, the contact angle on the surface on the substrate layer 101A side is more preferably 79° or less, and even more preferably 72° or less. The contact angle on the surface on the substrate layer 101A side is measured using an LSE-A210 manufactured by NIC Corporation, at the interface between the substrate and the water droplet 5 seconds after the water droplet is applied.

[0044] In the present embodiment, the contact angle of the surface on the substrate layer 101A side can be suitably reduced to 80° or less by, for example, subjecting the surface on the substrate layer 101A side to a corona treatment. The corona treatment can be performed by irradiating the surface on the substrate layer 101A side with corona discharge using a commercially available corona surface treatment device. The corona treatment conditions are, for example, treating the surface on the substrate layer 101A side at an irradiation output of 1 kW or more and a speed of 10 MT / min, thereby reducing the contact angle of the surface on the substrate layer 101A side to 80° or less.

[0045] Furthermore, when printing ink on the surface of the exterior member 101, a corona treatment is performed, followed by a step of printing ink on at least a portion of the surface of the base material layer 101A. The printing method is not particularly limited, but inkjet printing or pad printing is preferred when printing on the molded exterior member 101. The exterior member 101 of the energy storage device 10 of this embodiment has a contact angle of 80° or less on the surface of the base material layer 101A. This allows ink to be suitably printed even by pad printing, in which ink is easily repelled by the base material layer 101A, which has a lubricant on its surface. Therefore, it is possible to suitably form prints such as barcodes, patterns, and characters on at least a portion of the surface of the base material layer 101A.

[0046] 4 is a side view showing a state in which the exterior member 101 is wrapped around the electrode body 200 during the manufacturing process of the electricity storage device 10. As shown in FIG. 4, the exterior member 101 is wrapped around the electrode body 200. In this case, the outermost layer of the electrode body 200 does not necessarily have to be an electrode, and may be, for example, a protective tape or a separator. With the exterior member 101 wrapped around the electrode body 200, the surfaces (thermally adhesive resin layers) of the exterior member 101 facing each other are heat-sealed to form a first sealing portion 110.

[0047] The root portion of the first sealing unit 110 is preferably located on a side 135 of the exterior body 100. In the present embodiment, the side 135 is formed at the boundary between the first surface 130 and the second surface 140, which has a smaller area than the first surface 130. That is, in the present embodiment, the root portion of the first sealing unit 110 can be said to be formed at the boundary between the first surface 130 and the second surface 140, and can be said to be located on neither the first surface 130 nor the second surface 140. The root portion of the first sealing unit 110 may be located on a position other than the side 135. That is, the root portion of the first sealing unit 110 may be located on any surface, such as the first surface 130 or the second surface 140 of the exterior body 100. In the energy storage device 10, the first sealing unit 110 is bent toward the second surface 140 around the side 135. In the power storage device 10, the first sealing portion 110 contacts the second surface 140 and covers substantially the entire second surface 140. Note that "substantially the entire second surface 140" means a region that occupies 75% or more of the area of ​​the second surface 140.

[0048] That is, in the power storage device 10, the first sealing portion 110 is not formed on the first surface 130, which has a large area. The first surface 130 is flatter than when a sealing portion such as the first sealing portion 110 is in contact with the first surface 130. Therefore, even if another power storage device 10 is placed on the first surface 130, the other power storage device 10 will not tilt. As a result, the power storage device 10 can suppress unevenness in the distribution of pressure applied to the lower power storage device 10 when multiple power storage devices 10 are stacked. In other words, when multiple power storage devices 10 are stacked to form a module, the first sealing portion 110 is not disposed on the surface (first surface 130) adjacent to the adjacent power storage device 10. Furthermore, such a configuration is preferable from the viewpoint that high pressure must be applied uniformly from the outer surface of the battery in all-solid-state batteries to exhibit battery performance.

[0049] Furthermore, in the power storage device 10, the base portion of the first sealing portion 110 is located on a side 135 of the exterior body 100. Therefore, with the power storage device 10, a wider bonding area can be ensured in the first sealing portion 110 compared to when the base portion of the first sealing portion 110 is located on the second surface 140 (for example, in the central portion of the second surface 140 in the direction of arrow UD). Note that the bonding area of ​​the first sealing portion 110 does not necessarily have to be the entire area of ​​the first sealing portion 110, and may be a part of the first sealing portion 110, such as only the vicinity of the base portion of the first sealing portion 110, for example.

[0050] Furthermore, in the energy storage device 10, substantially the entire second surface 140 is covered by the first sealing portion 110. That is, in the energy storage device 10, the length of the first sealing portion 110 in the direction of the arrows UD is longer than in a case where the first sealing portion 110 covers only half or less of the second surface 140 (see FIG. 3 ). Therefore, the energy storage device 10 can ensure a wide bonding area in the first sealing portion 110. Furthermore, because substantially the entire second surface 140 is covered by the first sealing portion 110, the energy storage device 10 remains stable even if the energy storage device 10 is placed upright with the second surface 140 in contact with a mounting surface. That is, the energy storage device 10 is unlikely to tilt relative to the mounting surface. Therefore, this configuration is effective, for example, when forming a module by arranging multiple energy storage devices 10 side by side.

[0051] Fig. 5 is a view from below showing a state in which the exterior member 101 is wrapped around the electrode body 200 during the manufacture of the electricity storage device 10. As shown in Fig. 5, in the electricity storage device 10, the direction along the side 135 is the transverse direction (TD) of the exterior member 101, and the direction perpendicular to the side 135 is the machine direction (MD) of the exterior member 101. In other words, the direction along the side 135 is the direction (TD) perpendicular to the flow direction (MD) of the exterior member 101.

[0052] In the electricity storage device 10, the first sealing portion 110 is folded along the edge 135, and the direction along the edge 135 is perpendicular to the flow direction of the exterior member 101. Therefore, according to the electricity storage device 10, even if a fold is formed in the direction perpendicular to the flow direction of the exterior member 101, the exterior member 101 is unlikely to break, and therefore, the possibility of the first sealing portion 110 breaking due to the bending of the first sealing portion 110 can be reduced.

[0053] The machine direction (MD) of the exterior member 101 corresponds to the rolling direction (RD) of the metal foil (aluminum alloy foil, etc.) of the barrier layer included in the exterior member 101. The TD of the exterior member 101 corresponds to the TD of the metal foil. The rolling direction (RD) of the metal foil can be determined by the rolling marks.

[0054] Furthermore, the sea-island structure can be confirmed by observing multiple cross sections of the heat-fusible resin layer of the exterior member 101 with an electron microscope, and the direction parallel to the cross section in which the average diameter of the islands in the direction perpendicular to the thickness direction of the heat-fusible resin layer (hereinafter also referred to as the "length direction of the heat-fusible resin layer") is largest can be determined as the MD. When the MD of the exterior member 101 cannot be identified from the rolling marks of the metal foil, the MD can be identified by this method.

[0055] Specifically, the sea-island structure is confirmed by observing the longitudinal cross section of the heat-sealable resin layer and each cross section (a total of 10 cross sections) at angles of 10 degrees from the direction parallel to the longitudinal cross section and perpendicular to the longitudinal cross section. Next, for each island on each cross section, the island diameter d is measured as the linear distance connecting both ends in the direction perpendicular to the thickness direction of the heat-sealable resin layer. Next, the average of the diameters d of the 20 largest islands is calculated for each cross section. The direction parallel to the cross section with the largest average island diameter d is determined to be the MD.

[0056] Fig. 6 is a diagram schematically showing a part of the cross section taken along line VI-VI in Fig. 2. As shown in Fig. 6, second sealing portion 120 is sealed in a state in which exterior body 100 sandwiches electrode terminal 300.

[0057] Fig. 7 is a diagram illustrating a method for forming the second sealed portion 120. As shown in Fig. 7, the exterior member 101 is folded and the opposing surfaces (thermally adhesive resin layers) of the exterior member 101 are heat-sealed to form the second sealed portion 120. Although not shown in Fig. 7, the electrode terminal 300 is located between the opposing surfaces of the exterior member 101. An adhesive film that adheres to both metal and resin may be disposed between the electrode terminal 300 and the exterior member 101.

[0058] The adhesive film may be configured as one or more layers of a resin film made of, for example, a polyolefin resin or an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride. When the adhesive film is configured as two or more layers, it is preferable to arrange a resin film made of a polyolefin resin on the side that is bonded to the exterior member 101. When the adhesive film is configured as two or more layers, it is preferable to arrange a resin film made of an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride on the side that is bonded to the electrode terminal 300.

[0059] 6 again, the electrode body 200 includes a plurality of electrodes 210 (positive and negative electrodes). Current collectors 215 extending from each electrode 210 are connected to electrode terminals 300. In the electricity storage device 10, a portion of the electrode terminal 300 that is located outside the exterior body 100 is located at a position that is approximately half the thickness of the electricity storage device 10 in the thickness direction of the electricity storage device 10. In other words, the length L2 is approximately half the length L1. Note that "approximately half the thickness of the electricity storage device 10" means 35% to 65% of the thickness of the electricity storage device 10.

[0060] Therefore, according to the energy storage device 10, the difference between the longest and shortest distances between each of the multiple electrodes 210 and the electrode terminal 300 can be made smaller, for example, compared to when the electrode terminal 300 is located at approximately the same position as the first surface 130 in the thickness direction of the energy storage device 10.

[0061] <1-2. Manufacturing method of power storage device> Fig. 8 is a flowchart showing an example of a manufacturing procedure for the power storage device 10. The steps shown in Fig. 8 are performed, for example, by a manufacturing apparatus for the power storage device 10. Note that the manufacturing procedure for the power storage device 10 can be changed as desired.

[0062] The manufacturing device manufactures the exterior member 101 (step S100). The manufacturing device wraps the exterior member 101 around the electrode body 200 (step S110). The manufacturing device heat-seals the opposing surfaces (thermal adhesive resin layers) of the exterior member 101 to form the first sealed portion 110 (step S120). This results in the unfinished product shown in FIGS. 4 and 5 .

[0063] The manufacturing equipment folds the first sealing portion 110 so that the first sealing portion 110 contacts the second surface 140 (step S130). The manufacturing equipment folds the exterior member 101 with the electrode body 200 stored therein, and forms the second sealing portion 120 by heat-sealing the surfaces (thermally adhesive resin layers) of the exterior member 101 that face each other (step S140). This completes the electricity storage device 10.

[0064] <1-3. Features> As described above, in the energy storage device 10 according to the first embodiment, the first sealing portion 110 is bent toward the second surface 140, which has a smaller area. That is, the first sealing portion 110 is not present on the first surface 130, which has a larger area. Therefore, even if another energy storage device 10 is placed on the first surface 130, the other energy storage device 10 will not tilt. As a result, the energy storage device 10 can suppress unevenness in the distribution of pressure applied to the lower energy storage device 10 when multiple energy storage devices 10 are stacked. Furthermore, when used with an all-solid-state battery, the packaging form of the present invention is preferable because high pressure must be applied uniformly from the outer surface of the battery to maximize battery performance. Furthermore, in the energy storage device 10, the base portion of the first sealing portion 110 is located on the side 135 of the exterior body 100. Therefore, according to the energy storage device 10, when the first sealing portion 110 is fitted onto the second surface 140, a wider joint width can be ensured in the first sealing portion 110 compared to when the base portion of the first sealing portion 110 is on the second surface 140.

[0065] [2. Second Embodiment] In the electricity storage device 10 according to the first embodiment, the second sealed portion 120 is formed by folding the exterior member 101 and heat-sealing the surfaces of the exterior member 101 that face each other. However, the shape and method of forming the second sealed portion 120 are not limited to this. The following description will focus on the parts that are different from the first embodiment, and a description of the parts that are common to the first embodiment will be omitted.

[0066] 2-1. Configuration of the Power Storage Device Fig. 9 is a plan view schematically showing a power storage device 10X according to the second embodiment. Fig. 10 is a side view schematically showing the power storage device 10X. Fig. 11 is a perspective view schematically showing a lid 400.

[0067] 9, 10, and 11, the exterior body 100X is formed by fitting a lid body 400 into each of the openings at both ends of an exterior member 101 wrapped around the electrode assembly 200. With the lid body 400 fitted in place, the exterior member 101 and the lid body 400 are heat-sealed to form a second sealed portion 120X.

[0068] The lid body 400 is a bottomed tray-like member that is rectangular in plan view and is formed by, for example, cold-forming the exterior member 101. The lid body 400 does not necessarily have to be made of the exterior member 101, but may be a metal molded product or a resin molded product. In the power storage device 10X, the lid body 400 is arranged so that the bottom side of the lid body 400 is located inside the exterior body 100X. In the power storage device 10X, the bottom side of the lid body 400 does not necessarily have to be located inside the exterior body 100X. In the power storage device 10X, the bottom side of the lid body 400 may be located outside the exterior body 100X. When the lid body 400 is a metal molded product or a resin molded product, it is preferable that the material constituting the lid body 400 has a certain thickness so that deformation of the exterior body 100X is suppressed even when the power storage devices 10X are arranged one on top of the other. The minimum thickness of the material constituting the lid 400 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum thickness of the material constituting the lid 400 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum thickness of the material constituting the lid 400 may be 20 mm or more. Preferred ranges for the thickness of the material constituting the lid 400 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 10 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 10 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 10 mm. In this disclosure, when the lid 400 is referred to as a metal molded product or a resin molded product, this does not include embodiments in which the lid 400 is composed solely of a film. The film is, for example, a film defined by the JIS (Japanese Industrial Standards) "Packaging Terminology" standard. The film specified by the JIS [Packaging Terminology] standard is a plastic membrane with a thickness of less than 250 μm. The thickness of the material constituting the lid body 400 may vary depending on the part of the lid body 400. When the thickness of the material constituting the lid body 400 varies depending on the part of the lid body 400, the thickness of the material constituting the lid body 400 is the thickness of the thickest part.

[0069] Furthermore, when the electrode body 200 is stored, the electrode terminal 300 passes between the lid body 400 and the exterior member 101 and protrudes to the outside of the exterior body 100X. That is, the lid body 400 and the exterior member 101 are heat-sealed with the electrode terminal 300 sandwiched between them. Note that in the power storage device 10X, the position from which the electrode terminal 300 protrudes to the outside does not necessarily have to be between the lid body 400 and the exterior member 101. For example, the electrode terminal 300 may protrude to the outside from a hole formed in any one of the six surfaces of the exterior body 100X. In this case, a small gap between the exterior body 100X and the electrode terminal 300 is filled with, for example, resin.

[0070] Furthermore, in the power storage device 10X, the lid body 400 and the electrode terminal 300 are provided as separate bodies. However, the lid body 400 and the electrode terminal 300 do not necessarily have to be provided as separate bodies. For example, the lid body 400 and the electrode terminal 300 may be formed integrally.

[0071] FIG. 12 is a diagram showing a first example in which the lid 400 and the electrode terminal 300 are integrally formed. As shown in FIG. 12 , in the first example, the electrode terminal 300 is pre-heat-sealed to the side of the lid 400. For example, when the lid 400 is formed of an exterior member 101, an adhesive film that adheres to both metal and resin, as described in the first embodiment, may be disposed between the lid 400 and the electrode terminal 300. When the adhesive film has two or more layers, it is preferable to dispose a resin film made of a polyolefin resin on the side that is bonded to the lid 400. When the adhesive film has two or more layers, it is preferable to dispose a resin film made of an acid-modified polyolefin resin, which is obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride, on the side that is bonded to the electrode terminal 300.

[0072] Fig. 13 is a diagram showing a second example in which the lid 400 and the electrode terminal 300 are integrally formed. As shown in Fig. 13, in the second example, the electrode terminal 300 passes through a hole formed in the bottom surface of the lid 400. A small gap in the hole in the bottom surface of the lid 400 is filled with, for example, resin.

[0073] Furthermore, in the power storage device 10X, a gas valve may be attached to a hole formed in the second sealing portion 120X or in any one of the six surfaces of the exterior body 100X. The gas valve is configured, for example, as a check valve or a breaker valve, and is configured to reduce the pressure inside the exterior body 100X when the pressure increases due to gas generated inside the power storage device 10X.

[0074] 14 is a flowchart showing an example of a manufacturing procedure for the power storage device 10X. The steps shown in FIG. 14 are performed by, for example, a manufacturing apparatus for the power storage device 10X. Note that the manufacturing procedure for the power storage device 10X can be changed as desired.

[0075] The manufacturing device wraps the exterior member 101 around the electrode body 200 (step S200). The manufacturing device heat-seals the opposing surfaces (thermal adhesive resin layers) of the exterior member 101 to form the first sealed portion 110 (step S210). This results in the unfinished product shown in Figures 4 and 5.

[0076] The manufacturing equipment folds the first sealing portion 110 so that the first sealing portion 110 contacts the second surface 140 (step S220). The manufacturing equipment houses the electrode assembly 200 in the unfinished product produced in step S220 and attaches lid bodies 400 to the openings at both ends (step S230). The manufacturing equipment forms the second sealing portion 120X by heat-sealing the exterior member 101 and the lid body 400 (step S240). This completes the electricity storage device 10X.

[0077] <2-3. Features> In the power storage device 10X according to the second embodiment, the first sealing portion 110 is also bent toward the second surface 140, which has a smaller area. Therefore, with the power storage device 10X, when a plurality of power storage devices 10X are stacked, it is possible to suppress unevenness in the distribution of pressure applied to the lower power storage device 10X.

[0078] <2-4. Other Features> In the power storage device 10X according to the second embodiment, the first sealing unit 110 does not necessarily have to be bent toward the second surface 140, which has a smaller area. For example, the first sealing unit 110 may be bent toward the first surface 130, which has a larger area. Furthermore, the base portion of the first sealing unit 110 does not necessarily have to be on the side 135 of the exterior body 100X. The base portion of the first sealing unit 110 may be located on a surface of the exterior body 100X other than the lid body 400, for example. Even in this case, the power storage device 10X according to the second embodiment includes, for example, the following features.

[0079] The energy storage device 10X comprises an electrode body (electrode body 200) and an outer casing (outer casing 100X) that seals the electrode body (electrode body 200). The outer casing (outer casing 100X) is wrapped around the electrode body (electrode body 200) and comprises an outer casing member (outer casing member 101) having openings formed at both ends, and a lid (lid 400) that seals the openings.

[0080] In the power storage device 10X, the second sealed portion 120X is not formed by heat-sealing the opposing surfaces of the exterior member 101 as in the first embodiment (see FIG. 7 ). In the power storage device 10X, the opening of the exterior member 101 wrapped around the electrode assembly 200 is sealed by the lid body 400. That is, the second sealed portion 120X is formed in the portion where the lid body 400 and the exterior member 101 overlap (see FIGS. 9 and 10 ). With this configuration, the area of ​​the second sealed portion 120X can be easily narrowed by adjusting the depth L3 ( FIG. 11 ) of the lid body 400.

[0081] Furthermore, in the power storage device 10X, an excessive load is not generated when the corner C1 ( FIGS. 9 and 10 ) of the electrode body 200 of the exterior member 101 pierces the exterior member 101 at a position covering the corner C1. This is because, as described above, in the power storage device 10X, the second sealed portion 120X is not formed by heat-sealing the opposing surfaces of the exterior member 101 as in the first embodiment.

[0082] Furthermore, the manufacturing procedure of the power storage device 10X is not limited to the procedure shown in the flowchart of Fig. 14. For example, the power storage device 10X may be manufactured according to the procedure shown in the flowchart of Fig. 15.

[0083] FIG. 15 is a flowchart showing another manufacturing procedure for the power storage device 10X according to the second embodiment. The steps shown in FIG. 15 are performed, for example, by a manufacturing apparatus for the power storage device 10X. The manufacturing apparatus attaches a member (e.g., the member shown in FIGS. 12 and 13 ) in which the electrode terminal 300 and the lid body 400 are integrated to the electrode body 200 (step S250). For example, the electrode terminal 300 is welded to the electrode body 200. The manufacturing apparatus then wraps the exterior member 101 around the electrode body 200 (step S260). The manufacturing apparatus forms the first sealing portion 110 by heat-sealing the opposing surfaces (thermally adhesive resin layers) of the exterior member 101, and forms the second sealing portion 120X by heat-sealing the exterior member 101 and the lid body 400 together (step S270). This completes the power storage device 10X. The power storage device 10X may be manufactured using this procedure.

[0084] [3. Third Embodiment] In a battery manufacturing process, a temporarily sealed electricity storage device typically undergoes a step of aging for a predetermined time in a predetermined temperature environment (hereinafter referred to as the aging step) for the purpose of allowing an electrolyte solution to penetrate into the electrode body. During the aging step, gas is generated from the electrode body 200, and it becomes necessary to discharge the gas to the outside of the battery. In the electricity storage device 10X according to the second embodiment, a mechanism for releasing the gas generated in the aging step in the final stage of manufacturing the electricity storage device 10X was not provided. In the electricity storage device 10Y according to the third embodiment, a mechanism for releasing the gas generated from the electrode body 200 in the final stage of manufacturing the electricity storage device 10Y is provided. Note that the following description will focus on differences from the second embodiment, and a description of parts common to the second embodiment will be omitted.

[0085] 16 is a side view of the power storage device 10Y in the middle of its manufacture, showing the exterior member 101Y wrapped around the electrode body 200. Fig. 17 is a bottom view of the power storage device 10Y in the middle of its manufacture, showing the exterior member 101Y wrapped around the electrode body 200 and the lid body 400 attached to the exterior member 101Y.

[0086] 16 and 17 , the piece 150 is formed when the exterior member 101Y is wrapped around the electrode body 200. The piece 150 is formed by joining mutually facing surfaces of the exterior member 101Y when the exterior member 101Y is wrapped around the electrode body 200. More specifically, the piece 150 is formed by joining (heat sealing) the peripheral edges of the mutually facing surfaces of the exterior member 101Y when the exterior member 101Y is wrapped around the electrode body 200. That is, a first sealed portion 154 is formed on the peripheral edge of the piece 150.

[0087] Furthermore, in the piece 150, a space 152 is formed where the opposing surfaces of the exterior member 101Y are not joined. In the vicinity of the side 135, joint regions 151 where the opposing surfaces of the exterior member 101Y are joined and unjoined regions 153 where the opposing surfaces of the exterior member 101Y are not joined are arranged alternately. That is, in the piece 150, a pattern of joint regions 151 is formed along the side 135.

[0088] The gas generated from the electrode body 200 is discharged to the outside of the exterior body 100Y by releasing the sealed state of the exterior body 100Y, for example by cutting off a portion of the piece 150. Note that the gas discharged to the outside of the exterior body 100Y here is not necessarily limited to the gas generated from the electrode body 200, but may be a gas other than the gas generated from the electrode body 200, such as air, water vapor, or hydrogen sulfide.

[0089] Thereafter, the portion including the vicinity of side 135 is heat-sealed in a strip shape, thereby sealing the exterior body 100Y again. This completes the energy storage device 10Y. In the completed energy storage device 10Y, near side 135, regions where the bonding strength between the opposing surfaces of the exterior member 101Y is strong and regions where the bonding strength between the surfaces is weak are alternately arranged along side 135. In other words, in the heat-sealed portion near side 135, thin portions and thick portions are alternately arranged along side 135. This is because, by heat-sealing the vicinity of side 135 again, the unbonded region 153 is single-sealed, but the bonded region 151 is double-sealed.

[0090] 18 is a flowchart showing an example of a manufacturing procedure for the power storage device 10Y. The steps shown in Fig. 18 are performed by, for example, a manufacturing apparatus for the power storage device 10Y. Note that the manufacturing procedure for the power storage device 10Y can be changed as desired.

[0091] The manufacturing equipment wraps the exterior member 101Y around the electrode body 200 (step S300). The manufacturing equipment heat-seals the peripheral edges of the opposing surfaces (thermally adhesive resin layers) of the exterior member 101Y to form the first sealed portion 154 (step S310). The manufacturing equipment heat-seals the opposing surfaces of the exterior member 101Y near the sides 135 to form the pattern of the bonding region 151 (step S320).

[0092] The manufacturing device attaches the lids 400 to the openings at both ends with the electrode assembly 200 housed in the unfinished product produced in step S320 (step S330). The manufacturing device heat-seals the exterior member 101Y and the lids 400 to form the second sealed portion 120X (step S340). Then, an aging process is performed.

[0093] The manufacturing equipment removes gas generated during the aging process by, for example, cutting off piece 150 (step S350). The manufacturing equipment reseals exterior body 100Y by heat-sealing a portion of piece 150 including joining region 151 in a strip shape and removing the edge portion (step S360). Thereafter, piece 150 is folded toward second surface 140, thereby completing electricity storage device 10Y.

[0094] <3-3. Features> In the electricity storage device 10Y according to the third embodiment, the piece 150 including the first sealing portion 154 is also folded toward the second surface 140, which has a smaller area. Therefore, with the electricity storage device 10Y, when a plurality of electricity storage devices 10Y are stacked, unevenness in the distribution of pressure applied to the lower electricity storage device 10Y can be suppressed. When used in an all-solid-state battery, the packaging form of the present invention is preferred because it is necessary to apply high pressure uniformly from the outer surface of the battery to exhibit battery performance.

[0095] [4. Fourth Embodiment] In the power storage device 10X according to the second embodiment, the positions at which the electrode terminals 300 protrude to the outside are between the lid 400 and the exterior member 101. However, the positions at which the electrode terminals 300 protrude to the outside are not limited to this. The following description will focus on the parts that are different from the second embodiment, and a description of the parts that are common to the second embodiment will be omitted.

[0096] <4-1. Configuration of the Power Storage Device> FIG. 19 is a plan view schematically illustrating a power storage device 10XA according to the fourth embodiment. FIG. 20 is a side view schematically illustrating the power storage device 10XA. In a plan view, the exterior body 100X of the power storage device 10XA includes a pair of long sides 100XA and a pair of short sides 100XB. The exterior body 100X is configured by fitting a lid body 400 into each of openings along the long sides 100XA of an exterior member 101 wrapped around the electrode assembly 200. With the lid body 400 fitted, the exterior member 101 and the lid body 400 are heat-sealed to form a second sealing portion 120X. A through-hole (not shown) is formed in the lid body 400. Two electrode terminals 300 protrude from the through-holes of the lid body 400 to the outside of the exterior body 100X. The two electrode terminals 300 are shaped to follow the long sides 100XA of the exterior body 100X. Small gaps between the through holes and the electrode terminals 300 are filled with, for example, resin. In the fourth embodiment, the first sealing portion 110 is formed on one side of the pair of short sides 100XB.

[0097] The position from which the electrode terminal 300 protrudes in the lid body 400 in the thickness direction (arrow UD direction) of the power storage device 10XA can be selected arbitrarily. In the fourth embodiment, as shown in FIG. 20 , the electrode terminal 300 protrudes from approximately the center of the lid body 400 to the outside of the exterior body 100X in the thickness direction of the power storage device 10XA. The length of the electrode terminal 300 in the depth direction (arrow FB direction) of the power storage device 10XA can be selected arbitrarily. In the fourth embodiment, the length of the electrode terminal 300 in the depth direction (arrow FB direction) of the power storage device 10XA is substantially the same as the length of the electrode body 200.

[0098] <4-2. Features> In the power storage device 10XA according to the fourth embodiment, the electrode terminals 300 are arranged along the long side 100XA that is longer in the depth direction, and therefore it is possible to use larger electrode terminals 300. This makes it possible to provide a high-output power storage device 10XA.

[0099] [5. Modifications] The above-described embodiments are examples of possible forms of the exterior member for an electricity storage device, the electricity storage device, and the method for manufacturing an electricity storage device according to the present invention, and are not intended to limit the forms. The exterior member for an electricity storage device, the electricity storage device, and the method for manufacturing an electricity storage device according to the present invention may take forms different from those exemplified in the above-described embodiments. Examples of such forms include forms in which part of the configuration of each of the above-described embodiments is replaced, changed, or omitted, or forms in which a new configuration is added to each of the above-described embodiments. Some examples of modifications of each of the above-described embodiments are shown below. Note that the above-described embodiments can also be combined within the scope of not causing technical contradictions.

[0100] <5-1> In the above embodiment 1-4, one exterior member is wrapped around the electrode body 200. However, it is not necessary that one exterior member is wrapped around the electrode body 200. For example, two or more exterior members may be wrapped around the electrode body 200.

[0101] FIG. 21 is a side view showing the state in which exterior members 101Z1 and 101Z2 are wrapped around an electrode assembly 200 during the manufacturing process of an electric storage device according to a modified example. As shown in FIG. 21 , the electrode assembly 200 is surrounded by the exterior members 101Z1 and 101Z2. The first sealing portion 110Z is formed by joining the opposing surfaces of the exterior members 101Z1 and 101Z2. In this example, each first sealing portion 110Z is bent toward the second surface 140Z, not toward the first surface 130Z. Even with this configuration, it is possible to suppress uneven pressure distribution on the lower electric storage device when multiple electric storage devices are stacked. When used in an all-solid-state battery, the packaging form of the present invention is preferable because high pressure must be applied uniformly from the outer surface of the battery to maximize battery performance. Note that in this example, each first sealing portion 110Z does not necessarily need to be bent. In this modified example, each sealing portion 110Z may be sealed while sandwiching a part of the electrode terminal 300. Furthermore, in this modified example, each first sealing portion 110Z does not need to be formed on the side 135Z, and may protrude outward from approximately the center of the second surface 140Z in the thickness direction of the power storage device.

[0102] <5-2> In addition, in the above-described embodiments 1-4, the electrode body 200 is a so-called stack type formed by stacking a plurality of electrodes 210, but the form of the electrode body 200 is not limited to this. The electrode body 200 may be, for example, a so-called wound type formed by winding a positive electrode and a negative electrode with a separator interposed therebetween. The electrode body 200 may also be formed by stacking a plurality of so-called wound type electrode bodies.

[0103] <5-3> In addition, in the above-described embodiment 1-4, the second surface 140 is a flat surface that extends downward from the first surface 130 at a substantially right angle. However, the shape of the second surface 140 is not limited to this. For example, consider a case where the electrode body 200 is a wound electrode body, and flat and curved surfaces are formed on the outer periphery. Here, suppose that the area of ​​the flat surface is larger than the area of ​​the curved surface, and the first surface 130 covers the flat surface of the electrode body, and the second surface 140 covers the curved surface of the electrode body. In this case, the second surface 140 may be configured as a curved surface. In this case, the boundary portion where the second surface 140 extends downward from the first surface 130 is the edge 135.

[0104] <5-4> In the third embodiment, the bonding regions 151 are formed in four locations. However, the number of locations where the bonding regions 151 are formed is not limited to this. For example, the bonding regions 151 may be formed in two locations near both ends along the side 135, in one location near the center of the side 135, or in five or more locations.

[0105] <5-5> In addition, in the second embodiment, the electrode terminal 300 is disposed in the second sealing portion 120X. However, the position at which the electrode terminal 300 is disposed in the exterior body 100X is not limited to this. For example, as shown in FIG. 22 , in the second embodiment, the electrode terminal 300 can also be disposed in the first sealing portion 110. In other words, the first sealing portion 110 is sealed with the electrode terminal 300 sandwiched between them. In this modification, at least one of the two electrode terminals 300 may be bent toward the second surface 140, bent away from the second surface 140, or not bent so as to protrude outward from the side 135. In this modification, the electrode terminal 300 and the first sealing portion 110 can be easily sealed, thereby improving the hermeticity of the exterior body 100X. Furthermore, the electrode body 200 can be easily accommodated in the exterior body 100X. In this modification, for example, the lid 400 is fitted into each of the openings at both ends of the exterior member 101X as in the above-described embodiment 2. With the lid 400 fitted, the exterior member 101X and the lid 400 are heat-sealed to form the second sealing portion 120. In the first embodiment, the electrode terminal 300 may also be disposed in the first sealing portion 110.

[0106] <5-6> Furthermore, in the second embodiment, the configuration of the lid 400 can be modified as desired. FIG. 23 is a perspective view showing a lid 500, which is a modification of the lid 400. The lid 500 is, for example, plate-shaped and includes a first surface 500A facing the electrode assembly 200 (see FIG. 9 ) and a second surface 500B opposite the first surface 500A. A hole 500C penetrating the first surface 500A and the second surface 500B is formed in the center of the lid 500. The lid 500 is made of, for example, resin. In this modification, it is preferable to attach an adhesive film 530 that adheres to both the electrode terminal 300 and the lid 500 to a predetermined area including a portion of the electrode terminal 300 that is bonded to the lid 500. The specifications of the adhesive film 530 are the same as those of the adhesive film described in the first embodiment. In this modified example, the manufacturing method of the energy storage device 10X may include the steps of electrically connecting the electrode body 200 and the electrode terminal 300, manufacturing the lid body 500, and inserting the electrode terminal 300 connected to the electrode body 200 into the hole 500C of the lid body 500 (see Figure 24, hereinafter referred to as the "insertion step").

[0107] When the lid body 500 is plate-shaped, it is preferable that the lid body 500 have a certain thickness so that deformation of the exterior body 100X is suppressed even when the power storage device 10X is placed on top of it. From another perspective, when the lid body 500 is plate-shaped, it is preferable that the side surface of the lid body 500 have a certain thickness so that the side surface of the lid body 500 and the exterior member 101X can be heat-sealed appropriately when the second sealing portion 120X is formed. The minimum thickness of the lid body 500 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum thickness of the lid body 500 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum thickness of the lid body 500 may be 20 mm or more. Preferred ranges for the thickness of the material constituting the lid body 500 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 10 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 10 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 10 mm. In this disclosure, when the lid body 500 is described as being plate-shaped, this does not include embodiments in which the lid body 500 is composed solely of a film as defined by the JIS (Japanese Industrial Standards) [Packaging Terminology] standard. The thickness of the lid body 500 may vary depending on the portion of the lid body 500. When the thickness of the lid body 500 varies depending on the portion, the thickness of the lid body 500 is the thickness of the thickest portion.

[0108] The lid 500 may be formed by a member divided into a first portion 510 and a second portion 520, and may be manufactured by joining the first portion 510 and the second portion 520 together so as to sandwich the electrode terminal 300 and the adhesive film 530. In these modified examples, if a gap occurs between the adhesive film 530 and the hole 500C, the gap is preferably filled with a resin material such as hot melt or by resin welding.

[0109] When the lid body 500 is composed of a member divided into a first portion 510 and a second portion 520, the relationship between the width LA of the electrode terminal 300 and the width LB of the lid body 500 can be selected arbitrarily. From the viewpoint of more firmly bonding the electrode terminal 300 and the lid body 500, the ratio RA of the width LA to the width LB is preferably 50% or more. In the example shown in FIG. 25 , the widths LA and LB are substantially equal to each other; in other words, the ratio RA is 100%. When the ratio RA is 50% or more, the area of ​​the electrode terminal 300 that is bonded to the lid body 500 is large, and therefore, by heating the electrode terminal 300, the electrode terminal 300 and the lid body 500 can be more firmly bonded to each other. In this modification, the width LC of the adhesive film 530 is preferably substantially equal to the width LA of the electrode terminal 300.

[0110] The lid body 500 may be manufactured by insert molding the lid body 500 onto the electrode terminal 300 to which the adhesive film 530 is attached. In this case, the manufacturing method of the electricity storage device 10X includes the steps of electrically connecting the electrode body 200 and the electrode terminal 300, and insert molding the lid body 500 onto the electrode terminal 300 connected to the electrode body 200 (hereinafter referred to as the "insert molding step"). After the insert molding step, the exterior member 101 is wrapped around the electrode body 200 and the lid body 500. Note that in the insert molding step, it is preferable to place a heat insulating material to protect the electrode body 200 between the electrode body 200 and the portion where the lid body 500 is formed. It is preferable to remove the heat insulating material after the insert molding step.

[0111] In these modified examples, as shown in FIG. 26 , the exterior body 100X may have the second sealing portion 120X formed by joining the exterior member 101 and the second surface 500B of the lid 500 with the lid 500 fitted. The joining method between the exterior member 101 and the second surface 500B of the lid 500 is, for example, heat sealing. In this modified example, the exterior member 101 is joined to a wider area of ​​the lid 500, thereby improving the hermeticity of the exterior body 100X. Alternatively, the lid may be formed by folding the adhesive film 530, and the second sealing portion 120X may be formed by joining any portion of the adhesive film 530 to the exterior member 101X. In these modified examples, a barrier layer is preferably laminated on at least a portion of the surface of the lid 500. Alternatively, if the lid 500 has multiple layers, the barrier layer may be formed on any of the layers. The barrier layer may be made of, for example, aluminum, steel plate, or stainless steel.

[0112] FIG. 27 is a front view of a lid body 600, another modification of the lid body 400 in the second embodiment. The lid body 600 includes a metal portion 610, which is a portion where metal is exposed on the surface. The metal portion 610 is welded to the electrode 210 of the electrode assembly 200. The lid body 600 may be entirely composed of the metal portion 610, or the metal portion 610 may be partially formed. When the metal portion 610 is partially formed, the lid body 600 is composed of a multilayer material including a metal layer. When the lid body 600 is composed of a multilayer material with a metal layer as an intermediate layer, the metal portion 610 is a portion where layers other than the metal layer are partially removed to expose the metal layer. In the example shown in FIG. 27, the metal portion 610 of the lid body 600 functions as an electrode terminal, eliminating the need for space between the lid body 600 and the electrode 210. This allows the power storage device 10X (see FIG. 9) to be compact.

[0113] Figure 28 is a front view of a lid body 700 that is another modification of the lid body 400 in the second embodiment. The lid body 700 includes a metal portion 710 made of a metal material and a non-metal portion 720 that is connected to the metal portion 710 and made of a resin material. The metal portion 710 is welded to the electrode 210 of the electrode assembly 200. In the example shown in Figure 28, the metal portion 710 of the lid body 700 functions as an electrode terminal, so there is no need for space between the lid body 700 and the electrode 210. This allows the power storage device 10X (see Figure 9) to be configured in a compact size.

[0114] <5-7> In the first embodiment, the second sealed portion 120 is formed by folding the exterior member 101 and heat-sealing the thermally adhesive resin layers of the exterior member 101. However, the method for forming the second sealed portion 120 is not limited to this. FIG. 29 is a plan view schematically illustrating an energy storage device 10 having a modified second sealed portion 120Y. The exterior member 101 has a protruding portion 101XA extending outward from the exterior body 100, and the second sealed portion 120Y is formed by heat-sealing the thermally adhesive resin layers 101C of the protruding portion 101XA to each other. In the portion of the protruding portion 101XA where the electrode terminal 300 is disposed, the thermally adhesive resin layer 101C of the protruding portion 101XA and the electrode terminal 300 are heat-sealed. According to this modified example, the second sealed portion 120Y can be heat-sealed more firmly, thereby improving the hermeticity of the exterior body 100. In this modification, the protruding portion 101XA may be cut as necessary except for the portion heat-sealed to the electrode terminal 300. This modification can also be applied to the modification shown in FIG.

[0115] <5-8> In the first embodiment, the shape of the exterior body 100 can be changed as desired. As shown in FIG. 30A , the exterior body 100 may be composed of at least a first exterior member 101AX and a second exterior member 101BX. The specifications of the first exterior member 101AX and the second exterior member 101BX are the same as those of the exterior member 101. At least one of the first exterior member 101AX and the second exterior member 101BX has a recess 101AY that accommodates the electrode assembly 200. In the example shown in FIG. 30A , the recess 101AY is formed in the first exterior member 101AX by, for example, cold forming. The recess 101BY is formed in the second exterior member 101BX by, for example, cold forming. One of the first exterior member 101AX and the second exterior member 101BX may be sheet-shaped without a recess.

[0116] As shown in Fig. 30B , the first exterior member 101AX and the second exterior member 101BX may be separated by folding back a single exterior member. In the example shown in Fig. 30B , a recess 101AY for accommodating the electrode assembly 200 may be formed in the first exterior member 101AX. As shown in Fig. 30C , the peripheral edge of the first exterior member 101AX and the peripheral edge of the second exterior member 101BX folded back onto the first exterior member 101AX may be joined at edges other than the folded edge to form a peripheral seal portion 100AR. As shown in Fig. 30D , at least a portion of the peripheral seal portion 100AR may be folded back to fit along the electrode assembly 200.

[0117] Examples of exterior body 100 having a recess include the examples shown in Figures 30A, 30C, and 30D, as well as so-called folding trays disclosed in Japanese Patent Application Laid-Open No. 2019-102332 and Japanese Patent Application Laid-Open No. 2019-102333.

[0118] In addition to the examples shown in Figures 30A, 30C, and 30D, the exterior body 100 may be a brick-type pouch (see Figure 29), a Gabel-top type pouch, a standing type pouch, a gusset type pouch, a three-sided sealed pouch, a four-sided sealed pouch, or a pillow package.

[0119] <5-9> In the first embodiment, the method for forming the first sealing portion 110 can be selected arbitrarily. As shown in FIG. 31 , for example, in step S120 (see FIG. 8 ), the manufacturing apparatus may form the first sealing portion 110 by pressing the seal bar 800 against a position away from the base 135X of the portion 110Y of the exterior body 100 where the first sealing portion 110 is to be formed. According to this manufacturing method, as shown in FIG. 32 , the first sealing portion 110 is formed with a recess 110X, which is a trace of the seal bar 800 being pressed against it. In the portion of the exterior body 100 where the recess 110X is formed, opposing surfaces (thermally adhesive resin layers) of the exterior member 101 are directly bonded to each other. Between the recess 110X of the exterior body 100 and the base 135X, a polymer pool 900, in which a portion of the resin constituting the exterior member 101 has melted, is formed between the opposing surfaces of the exterior member 101. In the portion of the exterior body 100 between the recess 110X and the base 135X, the facing surfaces (thermally adhesive resin layers) of the exterior member 101 are joined via a poly pool 900. That is, in this modification, the first sealing portion 110 includes a portion where the facing surfaces of the exterior member 101 are directly joined, and a portion where the facing surfaces of the exterior member 101 are joined via the poly pool 900. The poly pool 900 prevents water vapor and the like from entering the interior of the exterior body 100 from the outside, thereby improving the barrier properties of the exterior body 100. Note that when the seal bar 800 is pressed against the portion 110Y, the facing surfaces of the exterior member 101 in the portion where the poly pool 900 is formed, in other words, the portion between the recess 110X and the base 135X, must be in contact with each other.

[0120] The distance X between the base 135X and the edge 810 of the seal bar 800 in the LR direction, in other words, the distance between the base 135X and the recess 110X in the LR direction, can be selected arbitrarily. From the viewpoint of forming the polymer pool 900 over a wider area, the distance X is preferably, for example, 1 mm or more, more preferably 1.5 mm or more, and even more preferably 1.7 mm or more. From the viewpoint of forming the first sealing portion 110 compactly, the distance X is preferably, for example, 10 mm or less, more preferably 5 mm or less, and even more preferably 3 mm or less. Preferred ranges for the distance X include, for example, approximately 1 mm to 10 mm, approximately 1 mm to 5 mm, approximately 1 mm to 3 mm, approximately 1.5 mm to 10 mm, approximately 1.5 mm to 5 mm, approximately 1.5 mm to 3 mm, approximately 1.7 mm to 10 mm, approximately 1.7 mm to 5 mm, and approximately 1.7 mm to 3 mm. The distance X is most preferably, for example, 2 mm. Alternatively, the distance X may be substantially 0. When the distance X is substantially 0, the seal bar 800 is pressed against the exterior body 100 so that the base 135X and the edge 810 of the seal bar 800 substantially coincide with each other. Note that "substantially coincident" includes cases where the base 135X and the edge 810 of the seal bar 800 completely coincide with each other, and cases where the positions of the base 135X and the edge 810 of the seal bar 800 are slightly misaligned due to manufacturing errors or the like. Therefore, "the distance X is substantially 0" also includes cases where the distance X is less than 1 mm, for example. These modifications can also be applied to the second to fourth embodiments. Note that depending on the shape of the portion of the recess 110X corresponding to the edge 810 of the seal bar 800, the distance between the base 135X and the recess 110X may not be constant. In such cases, the distance X may be the distance between the center of the recess 110X and the center of the base 135X in the FB direction. In another example, the distance X may be calculated based on the average value of multiple values ​​including the maximum and minimum values ​​of the distance between the base 135X and the recess 110X. Similarly, depending on the shape of the base 135X, the distance between the base 135X and the recess 110X may not be constant. In such a case, the distance X may be the distance between the center of the base 135X and the center of the recess 110X in the FB direction.In another example, the distance X may be calculated based on the average value of a plurality of values ​​including the maximum and minimum values ​​of the distance between the recess 110X and the base 135X.

[0121] In the second embodiment, as shown in FIG. 33 , the exterior body 100X may include a barrier film 91 that suppresses permeation of the electrolyte solution. The barrier film 91 is preferably disposed at least between the inner surface of the exterior member 101X and the electrode assembly 200. The barrier film 91 is preferably bonded to the inner surface of the exterior member 101X. The barrier film 91 is preferably made of a material that allows permeation of gas generated within the exterior body 100X. The material constituting the barrier film 91 is, for example, a resin film or a porous film. Because the exterior body 100X includes the barrier film 91, deterioration of the exterior member 101X due to the electrolyte solution can be suppressed.

[0122] In the first embodiment, as shown in FIG. 34 , the exterior body 100 may include a buffer film 92 for increasing the strength of the exterior member 101. The buffer film 92 is preferably disposed on the inner surface of the exterior member 101, at least at the corners 100Z of the exterior body 100. Because the exterior body 100 includes the buffer film 92, the occurrence of pinholes in the exterior body 100 can be suppressed. Examples of materials that make up the buffer film 92 include polyester-based materials, polyolefin-based materials, and fluorine-based materials. In this modification, as shown in FIG. 33 , the second sealing portion 120 may be formed by joining the inner surface of the exterior member 101 and the electrode terminal 300. A space 93 between the second sealing portion 120 and the electrode body 200 is preferably filled with an electrolyte.

[0123] In the above-mentioned first embodiment, it has been explained that an adhesive film that adheres to both metal and resin may be disposed between the electrode terminal 300 and the exterior member 101, but an adhesive film may also be disposed in a similar manner in other embodiments.

[0124] In the above-mentioned second embodiment, it has been explained that an adhesive film that adheres to both metal and resin, similar to that in the first embodiment, may be disposed between the lid body 400 and the electrode terminal 300, but an adhesive film may also be disposed in a similar manner in other embodiments.

[0125] [6. Examples] The inventors of the present application conducted a first test and a second test on the exterior members for an electricity storage device of Examples and Reference Examples. Note that, for the sake of convenience of explanation, the following description will be given by assigning the same reference numerals as in the embodiment to elements constituting the exterior members for an electricity storage device of Examples and Reference Examples that are the same as in the embodiment.

[0126] <6-1. First Test> The first test was a test to confirm the limit forming depth when cold forming was performed on the exterior members 101 of Example 1 and Reference Example 1. In the first test, a slip agent was applied to both surfaces of the exterior members 101 of Example 1 and Reference Example 1, and cold forming was performed.

[0127] The exterior member 101 of Example 1 has a layer structure of, from the outside in, a PET film layer (base material layer 101A) / adhesive / ONY film layer / adhesive / aluminum layer (barrier layer 101B) / acid-modified polypropylene layer / polypropylene layer (heat-sealable resin layer 101C).

[0128] The PET film layer is 12 μm thick. The ONY film layer is 15 μm thick. The aluminum layer is 40 μm thick. The acid-modified polypropylene layer is 40 μm thick. The polypropylene layer is 40 μm thick. The aluminum layer is made of recycled 8021 material.

[0129] The specifications of the exterior member 101 of Reference Example 1 are the same as those of the exterior member 101 of Example 1, except that the material constituting the aluminum layer is a virgin material rather than a recycled material.

[0130] The limit forming depth of the exterior member 101 of Example 1 was 8.6 mm. The limit forming depth of the exterior member 101 of Reference Example 1 was 8.8 mm. Therefore, it was confirmed that even when recycled material was used as the material constituting the barrier layer 101B of the exterior member 101, a cold forming depth equivalent to that obtained when virgin raw material was used as the material constituting the barrier layer 101B of the exterior member 101 was obtained.

[0131] 6-2. Second Test The second test was a test to confirm the wrappability of the exterior members 101 of Example 2 and Reference Example 2 when they were wrapped around the electrode body 200 and the lid body 400 .

[0132] The specifications of the exterior member 101 of Example 2 are the same as those of the exterior member 101 of Example 1. The specifications of the exterior member 101 of Reference Example 2 are the same as those of the exterior member 101 of Reference Example 1.

[0133] It was confirmed that the exterior member 101 of Example 2 and the exterior member 101 of Reference Example 2 could be wrapped around the electrode body 200 and the lid body 400 with little difference in wrinkles and slack. Therefore, it was confirmed that even when recycled material was used as the material constituting the barrier layer 101B of the exterior member 101, the same degree of wrapability around the electrode body 200 and the lid body 400 could be obtained as when virgin raw materials were used as the material constituting the barrier layer 101B of the exterior member 101.

[0134] 10, 10X, 10XA, 10Y, 10Z: Electricity storage device 100, 100X, 100Y: Exterior body 101, 101Y, 101Z1, 101Z2: Exterior member 101A: Base material layer 101B: Barrier layer 101C: Thermally adhesive resin layer 101AX: First exterior member 101BX: Second exterior member 101AY: Recess 110, 110Z, 154: First sealing portion 200: Electrode body

Claims

1. The laminate includes, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer. The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate. Exterior materials for electricity storage devices.

2. The present invention is composed of a laminate including, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer, The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate, and is composed only of recycled materials. Exterior materials for electricity storage devices.

3. The barrier layer is made of the aluminum alloy containing iron, In 100% by mass of the aluminum alloy containing iron, the content of the iron is in the range of 0.1 to 9.0% by mass. The exterior member for an electricity storage device according to claim 1 or 2.

4. The barrier layer is made of the aluminum alloy containing magnesium, In 100% by mass of the aluminum alloy containing magnesium, the content of the magnesium is in the range of 0.2 to 5.6 mass%. The exterior member for an electricity storage device according to claim 1 or 2.

5. The barrier layer is made of the aluminum alloy, The aluminum alloy is JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O, JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P- H14, JIS H4000:2014 A8079P-H14, JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, or Composition specified in JIS H4000:2017 A5052P-O The exterior member for an electricity storage device according to claim 1 or 2.

6. An exterior member for an electricity storage device; an electrode assembly packaged by the exterior member for an electricity storage device; The exterior member for an electricity storage device includes: The laminate includes, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer. The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate. Energy storage device.

7. An exterior member for an electricity storage device, an electrode assembly packaged by the exterior member for an electricity storage device; The exterior member for an electricity storage device includes: The laminate includes, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer. The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate, and is composed only of recycled materials. Energy storage device.

8. The barrier layer is made of the aluminum alloy containing iron, In 100% by mass of the aluminum alloy containing iron, the content of the iron is in the range of 0.1 to 9.0% by mass. The electricity storage device according to claim 6 or 7.

9. The barrier layer is made of the aluminum alloy containing magnesium, In 100% by mass of the aluminum alloy containing magnesium, the content of the magnesium is in the range of 0.2 to 5.6 mass%. The electricity storage device according to claim 6 or 7.

10. The barrier layer is made of the aluminum alloy, The aluminum alloy is JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O, JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P- H14, JIS H4000:2014 A8079P-H14, JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, or Composition specified in JIS H4000:2017 A5052P-O The electricity storage device according to claim 6 or 7.

11. The electrode body is wrapped in the exterior member for the power storage device, and a first sealing portion is formed by joining opposing surfaces of the exterior member for the power storage device to each other and sealing the electrode body in the state where the exterior member for the power storage device is wrapped in the exterior member for the power storage device. The electricity storage device according to claim 6 or 7.

12. a lid that seals the electrode body together with the exterior member for the electricity storage device; a second sealing portion in which the lid and the exterior member for an electricity storage device are joined together, The electricity storage device according to claim 6 or 7.

13. The exterior member for the electricity storage device includes a first exterior member and a second exterior member, At least one of the first exterior member and the second exterior member is formed with a recess for accommodating the electrode body. The electricity storage device according to claim 6 or 7.

14. A method for producing the electricity storage device according to claim 6, comprising the steps of: The method includes a step of manufacturing the exterior member for an electricity storage device, which is composed of a laminate including, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer; The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate. A method for manufacturing an electricity storage device.

15. A method for producing the energy storage device according to claim 7, comprising the steps of: The method includes a step of manufacturing the exterior member for an electricity storage device, which is composed of a laminate including, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer; The barrier layer contains at least one of recycled materials selected from the group consisting of aluminum alloy, stainless steel, titanium steel, and steel plate, and is composed only of recycled materials. A method for manufacturing an electricity storage device.