Power storage device and lid unit

Abstract

This power storage device comprises an electrode body and an exterior body which seals the electrode body. The exterior body includes an exterior film wrapping the electrode body, a lid body sealing the electrode body together with the exterior film, and a first sealing portion being a portion where the exterior film is closed. The power storage device is provided with at least one of a check valve and an unsealing valve in the first sealing portion.

Description

Power storage device, lid unit

[0001] The present invention relates to an electricity storage device and a lid unit.

[0002] Patent Document 1 discloses an example of an electricity storage device. This electricity storage device includes an electrode assembly and an exterior body that seals the electrode assembly. The exterior body includes an exterior film that wraps the electrode assembly so as to form an opening, and a lid that is placed over the opening. The exterior film and the lid are joined together.

[0003] JP 2022-123686 A

[0004] When the electricity storage device is a lithium ion battery, for example, gas may be generated due to the evaporation of an organic solvent in the electrolyte, and the internal pressure of the exterior body may increase. No consideration has been given to discharging the gas generated inside the exterior body of the electricity storage device to the outside.

[0005] An object of the present invention is to provide an electricity storage device that can discharge gas generated inside an exterior body, and a lid unit used for this electricity storage device.

[0006] The energy storage device according to a first aspect of the present invention is an energy storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body includes an exterior film that wraps the electrode body, a lid that seals the electrode body together with the exterior film, and a first sealing portion that is a portion where the exterior film is closed, and the energy storage device comprises at least one of a check valve and an open valve that are arranged in the first sealing portion.

[0007] An energy storage device according to a second aspect of the present invention is the energy storage device according to the first aspect, wherein the first sealed portion is a portion sealed by joining the inner surfaces of the exterior film that face each other, or a portion sealed by joining the outermost layer and the innermost layer of the exterior film.

[0008] A third aspect of the present invention provides an energy storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body includes an exterior film that wraps the electrode body, a lid that seals the electrode body together with the exterior film, and a second sealing portion in which the lid body and the exterior film are joined, and the energy storage device comprises at least one of a check valve and an open valve that are arranged in the second sealing portion.

[0009] An electricity storage device according to a fourth aspect of the present invention is the electricity storage device according to the third aspect, wherein the lid body has a recess formed on a side surface, and at least one of the check valve and the open valve is disposed in the recess.

[0010] An electric storage device according to a fifth aspect of the present invention is an electric storage device according to the third or fourth aspect, wherein the electric storage device includes the check valve, the outer casing includes at least two lid bodies, and the opening pressure of the check valve arranged in the second sealing portion corresponding to one of the lid bodies is lower than the opening pressure of the check valve arranged in the second sealing portion corresponding to the other lid body.

[0011] An electric storage device according to a sixth aspect of the present invention is an electric storage device according to the third or fourth aspect, wherein the electric storage device includes the opening valve, the outer casing includes at least two of the lid bodies, and the opening pressure of the opening valve arranged in the second sealing portion corresponding to one of the lid bodies is lower than the opening pressure of the opening valve arranged in the second sealing portion corresponding to the other of the lid bodies.

[0012] The seventh aspect of the present invention is an energy storage device according to the third or fourth aspect, wherein the outer casing includes at least two lids, and at least one of the check valve and the open valve is disposed in the second sealing portion corresponding to one of the lids, and neither the check valve nor the open valve is disposed in the second sealing portion corresponding to the other lid.

[0013] An eighth aspect of the present invention provides an energy storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body includes an exterior film that wraps the electrode body and a lid that seals the electrode body together with the exterior film, and the energy storage device comprises a check valve attached to the lid.

[0014] A ninth aspect of the present invention is an electric storage device according to the eighth aspect, wherein the outer casing includes at least two lids, and the opening pressure of the check valve attached to one of the lids is lower than the opening pressure of the check valve attached to the other lid.

[0015] The energy storage device according to a tenth aspect of the present invention is the energy storage device according to the eighth aspect, wherein the outer casing includes at least two lids, one of which has the check valve attached thereto and the other of which does not have the check valve attached thereto.

[0016] An electricity storage device according to an eleventh aspect of the present invention is an electricity storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body includes an exterior film that wraps the electrode body and a lid that seals the electrode body together with the exterior film, and the electricity storage device comprises an opening valve attached to the lid.

[0017] The energy storage device according to a twelfth aspect of the present invention is the energy storage device according to the eleventh aspect, wherein the outer casing has at least two lids, and the opening pressure of the opening valve attached to one of the lids is lower than the opening pressure of the opening valve attached to the other lid.

[0018] The energy storage device according to a thirteenth aspect of the present invention is the energy storage device according to the eleventh aspect, wherein the outer casing has at least two lids, one of which has the opening valve attached thereto and the other of which does not have the opening valve attached thereto.

[0019] A fourteenth aspect of the present invention provides an energy storage device comprising an electrode body and an exterior body that seals the electrode body, wherein the exterior body includes an exterior film that wraps the electrode body and a lid that seals the electrode body together with the exterior film, and the energy storage device comprises at least one of a check valve and an open valve that are attached in a position that allows gas generated inside the exterior body to be discharged.

[0020] A power storage device according to a fifteenth aspect of the present invention is the power storage device according to the fourteenth aspect, further comprising the check valve and the open valve, wherein the valve opening pressure of the check valve is lower than the valve opening pressure of the open valve.

[0021] A lid unit according to a sixteenth aspect of the present invention comprises a lid body used as an exterior body that seals an electrode body, and at least one of a check valve and an open valve attached to the lid body.

[0022] According to the electricity storage device of the present invention and the lid unit used in this electricity storage device, gas generated inside the exterior body can be discharged.

[0023] 1A . FIG. 1B is a perspective view schematically showing an electricity storage device according to a first embodiment. FIG. 1C is a diagram relating to a method for measuring the seal strength of a second sealed portion of the electricity storage device of FIG. 1A. FIG. 1D is a cross-sectional view showing an example of the layer structure of an exterior film included in the electricity storage device of FIG. 1A. FIG. 1E is a diagram showing a state in which the exterior film included in the electricity storage device of FIG. 1A is unfolded. FIG. 1F is a perspective view of a lid included in the electricity storage device of FIG. 1A. FIG. 1G is a front view of a check valve included in the electricity storage device of FIG. 1A. FIG. 1H is a flowchart showing an example of a manufacturing method for the electricity storage device of FIG. 1A. FIG. 1H is a perspective view schematically showing an electricity storage device according to a second embodiment. FIG. 1J is a cross-sectional view taken along line D8-D8 in FIG. 7. FIG. 1J is a perspective view schematically showing an electricity storage device according to a third embodiment. FIG. 1J is a cross-sectional view showing an example of the layer structure of an exterior film included in the electricity storage device of FIG. 9. FIG. 1K is a perspective view of an electricity storage device according to a fourth embodiment. FIG. 1K is a cross-sectional view of an electricity storage device according to a modification of the first embodiment. FIG. 1L is a front view of an electricity storage device according to a modification of the second embodiment. FIG. 1L is a front view of a lid included in the electricity storage device of FIG. 13. FIG. 1L is a front view of an electricity storage device according to another modification of the second embodiment. Fig. 16 is a front view of a lid provided in the electricity storage device of Fig. 15. Fig. 17 is a cross-sectional view showing another example of the arrangement of the opening valve provided in the electricity storage device of the fourth embodiment. Fig. 18 is a perspective view of an electricity storage device that is a modified example of the electricity storage device of the fourth embodiment.

[0024] Hereinafter, an electricity storage device according to one embodiment of the present invention will be described with reference to the drawings. In this specification, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the expression "2 to 15 mm" means 2 mm or more and 15 mm or less.

[0025] 1. First Embodiment 1-1. Configuration of Electricity Storage Device FIG. 1A is a plan view schematically illustrating an electricity storage device 10 according to a first embodiment. FIG. 1B relates to a method for measuring the seal strength of a second sealing portion 80 of the electricity storage device 10. FIG. 2 is a cross-sectional view illustrating the layer configuration of an exterior film 50 included in the electricity storage device 10 of FIG. 1A. FIG. 3 is a view illustrating the exterior film 50 included in the electricity storage device 10 of FIG. 1A in an unfolded state. FIG. 4 is a perspective view of a lid 60 included in the electricity storage device 10 of FIG. 1A. FIG. 5 is a front view of a check valve 90 included in the electricity storage device 10 of FIG. 1A. In FIG. 1A, the direction of arrow UD indicates the thickness direction of the electricity storage device 10, the direction of arrow LR indicates the width direction of the electricity storage device 10, and the direction of arrow FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UD, L, R, F, and B are common to all subsequent figures.

[0026] The energy storage device 10 includes an electrode body 20, an electrode terminal 30, and an exterior body 40. The electrode body 20 includes electrodes (positive and negative electrodes) constituting an energy storage member such as a lithium-ion battery, a capacitor, an all-solid-state battery, a semi-solid battery, a quasi-solid battery, a polymer battery, an all-resin battery, a lead-acid battery, a nickel-metal hydride battery, a nickel-cadmium battery, a nickel-iron battery, a nickel-zinc battery, a silver oxide-zinc battery, a metal-air battery, a polyvalent cation battery, or a capacitor, as well as a separator. In this embodiment, the shape of the electrode body 20 is approximately rectangular. Note that the term "approximately rectangular" includes not only a perfect rectangular parallelepiped, but also a solid that can be considered a rectangular parallelepiped by modifying the shape of a portion of its outer surface, for example. The shape of the electrode body 20 may be, for example, a cylinder or a polygonal prism.

[0027] In this embodiment, the power storage device 10 includes two electrode terminals 30. The electrode terminals 30 are metal terminals used for inputting and outputting electric power to and from the electrode body 20. One end of the electrode terminal 30 is electrically connected to an electrode (positive electrode or negative electrode) included in the electrode body 20. The other end of the electrode terminal 30 protrudes outward from, for example, an edge of the exterior body 40. Note that the electrode terminals 30 only need to be capable of inputting and outputting electric power to and from the electrode body 20, and may not, for example, protrude from the exterior body 40. When the lid body 60 described below is made of, for example, metal, the lid body 60 may also function as the electrode terminals 30. In this case, the lid body 60, which functions as an electrode terminal, may or may not protrude from the exterior body 40.

[0028] The metal material constituting the electrode terminal 30 is, for example, aluminum, nickel, copper, etc. For example, when the electrode body 20 is a lithium ion battery, the electrode terminal 30 connected to the positive electrode is usually made of aluminum, etc., and the electrode terminal 30 connected to the negative electrode is usually made of copper, nickel, etc. The outermost layer of the electrode body 20 does not necessarily have to be an electrode, and may be, for example, a protective tape or a separator.

[0029] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a lid body 60. The exterior film 50 wraps the electrode body 20. In the present embodiment, the exterior film 50 is wrapped around the electrode body 20. The lid body 60 is disposed on the side of the electrode body 20 in the FB direction. In another example, the electrode body 20 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings 40A are formed at both ends in the FB direction, and the openings 40A may be closed by the lid body 60. In yet another example, the electrode body 20 connected to the lid body 60 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings 40A are formed, and the openings 40A may be closed by the lid body 60.

[0030] An adhesive film 31 is preferably bonded to the electrode terminal 30 from the viewpoint of favorable adhesion to the lid 60. The adhesive film 31 can be any film that can bond the metal electrode terminal 30 and the resin lid 60. For example, the adhesive film 31 can be a polyolefin resin such as a polyethylene resin or a polypropylene resin, a cyclic polyolefin resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The adhesive film 31 can be a single-layer film or a film of two or more layers. In this embodiment, the adhesive film 31 is bonded to substantially the entire portion of the electrode terminal 30 that is covered by the lid 60.

[0031] For example, there is a method of forming a storage portion (recess) in the exterior film 50 through cold forming to accommodate the electrode assembly 20. However, it is not necessarily easy to form a deep storage portion using such a method. Attempting to form a deep storage portion (recess) by cold forming (for example, a forming depth of 15 mm) increases the likelihood of pinholes or cracks occurring in the exterior film 50, resulting in a decrease in battery performance. On the other hand, the exterior body 40 seals the electrode assembly 20 by wrapping the exterior film 50 around the electrode assembly 20, and therefore can easily seal the electrode assembly 20 regardless of the thickness of the electrode assembly 20. Note that in order to reduce the dead space between the electrode assembly 20 and the exterior film 50 and improve the volumetric energy density of the power storage device 10, it is preferable that the exterior film 50 be wrapped so as to contact the outer surface of the electrode assembly 20. Furthermore, in all-solid-state batteries, it is necessary to apply a high pressure uniformly from the outer surface of the battery to exhibit battery performance, so it is necessary to eliminate the space between the electrode assembly 20 and the exterior film 50. Therefore, it is preferable that the exterior film 50 be wrapped so as to contact the outer surface of the electrode assembly 20.

[0032] The exterior film 50 is, for example, a laminate (laminate film) having a base material layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in this order. Note that the exterior film 50 does not need to include all of these layers, and for example, it may not include the barrier layer 52. In other words, the exterior film 50 only needs to be made of a flexible and easily bendable material, and may be made of, for example, a resin film. Note that the exterior film 50 is preferably heat-sealable.

[0033] The substrate layer 51 included in the exterior film 50 is a layer that imparts heat resistance to the exterior film 50 and suppresses the occurrence of pinholes that may occur during processing or distribution. The substrate layer 51 is composed of, 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 substrate layer 51, the barrier layer 52 can be protected during processing of the exterior film 50 and breakage of the exterior film 50 can be suppressed. Furthermore, from the viewpoint of increasing the tensile elongation of the exterior film 50, 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 substrate layer 51 may be composed of both a stretched polyester resin layer and a stretched polyamide resin layer. From the viewpoint of film strength, the thickness of the substrate layer 51 is preferably, for example, 5 to 300 μm, and more preferably 5 to 150 μm.

[0034] The barrier layer 52 is a layer that prevents at least moisture penetration. The barrier layer 52 is bonded to the substrate layer 51 via, for example, an adhesive layer 54. Examples of the barrier layer 52 include metal foils, vapor-deposited films, and resin layers with barrier properties. Vapor-deposited films include metal vapor-deposited films, inorganic oxide vapor-deposited films, and carbon-containing inorganic oxide vapor-deposited films. Resin layers include fluorine-containing resins such as polyvinylidene chloride, polymers based on chlorotrifluoroethylene (CTFE), polymers based on tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers based on fluoroalkyl units, as well as ethylene-vinyl alcohol copolymers. The barrier layer 52 may also be a resin film having at least one of these vapor-deposited films and resin layers. The barrier layer 52 may be formed of multiple layers. The barrier layer 52 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 52 include aluminum alloys, stainless steel, titanium steel, and steel plates. When used as a metal foil, it is preferable that the metal material contains at least one of an aluminum alloy foil and a stainless steel foil.

[0035] In the barrier layer 52, the layer made of the aforementioned metal material may contain recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, and steel plate. These recycled materials can be obtained by known methods. Recycled aluminum alloy material can be obtained, for example, by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 52 may be made of recycled material alone, or may be made of a mixture of recycled and virgin material. Note that recycled metal material refers to metal material that has been made reusable by collecting, isolating, and refining various products used in the market or waste from manufacturing processes. Furthermore, virgin metal material refers to new metal material refined from natural metal resources (raw materials) and is not recycled material.

[0036] From the viewpoint of improving the formability or conformability of the exterior film 50, 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 formability, an aluminum alloy foil containing iron is preferable. In the iron-containing aluminum alloy foil (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 setting the iron content to 0.1% by mass or more, an exterior film 50 with better formability can be obtained. By setting the iron content to 9.0% by mass or less, an exterior film 50 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 other methods. From the perspective of improving the mechanical strength of the exterior film 50, 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 by JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14.

[0037] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. Furthermore, from the viewpoint of providing an exterior film 50 with excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0038] Specific examples of austenitic stainless steels that form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0039] In the case of a metal foil, the thickness of the barrier layer 52 should be sufficient to at least function as a barrier layer that prevents moisture penetration, and may be, for example, approximately 9 to 200 μm. The thickness of the barrier layer 52 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 52 is preferably approximately 10 μm or more, even more preferably approximately 20 μm or more, and more preferably approximately 25 μm or more. Preferred thickness ranges for the barrier layer 52 include approximately 10 to 85 μm, approximately 10 to 50 μm, approximately 10 to 40 μm, approximately 10 to 35 μm, approximately 20 to 85 μm, approximately 20 to 50 μm, approximately 20 to 40 μm, approximately 20 to 35 μm, approximately 25 to 85 μm, approximately 25 to 50 μm, approximately 25 to 40 μm, and approximately 25 to 35 μm. When the barrier layer 52 is made of an aluminum alloy foil, the above-mentioned range is particularly preferable. From the viewpoint of imparting high formability and high rigidity to the exterior film 50, the thickness of the barrier layer 52 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 film 50 facilitates deep drawing, which can contribute to increasing the capacity of the electricity storage device. Furthermore, because the rigidity of the exterior film 50 is increased, when the exterior film 50 is wrapped around the electrode body 20, the exterior film 50 can be suitably wrapped around the electrode body 20. Furthermore, when the capacity of the electricity storage device is increased, the weight of the electricity storage device increases, but increasing the rigidity of the exterior film 50 can contribute to high sealing performance of the electricity storage device.In particular, when the barrier layer 52 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 ranges for the thickness of 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.

[0040] Furthermore, when the barrier layer 52 is an aluminum foil, it is preferable that a corrosion-resistant coating be provided on at least the surface opposite the substrate layer 51 to prevent dissolution and corrosion. The barrier layer 52 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.) by performing, for example, a hydrothermal conversion treatment such as boehmite treatment, a chemical conversion treatment, an anodizing treatment, a plating treatment of nickel or chromium, or a corrosion prevention treatment such as applying a coating agent on the surface of the barrier layer 52. Specifically, the corrosion-resistant coating refers to a coating that improves the acid resistance of the barrier layer 52 (acid-resistant coating), a coating that improves the alkali resistance of the barrier layer 52 (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 52 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, if the barrier layer 52 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 52.

[0041] The corrosion-resistant coating prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the substrate layer 51 when the exterior film 50 is formed or wound, prevents dissolution and corrosion of the surface of the barrier layer 52 due to hydrogen fluoride produced by a reaction between an electrolyte and water, and particularly prevents dissolution and corrosion of aluminum oxide present on the surface of the barrier layer 52 when the barrier layer 52 is an aluminum alloy foil, and also improves the adhesion (wettability) of the surface of the barrier layer 52, thereby preventing delamination between the substrate layer 51 and the barrier layer 52 during heat sealing and between the substrate layer 51 and the barrier layer 52 during forming.

[0042] The heat-sealable resin layer 53 is bonded to the barrier layer 52 via, for example, an adhesive layer 55. The heat-sealable resin layer 53 included in the exterior film 50 is a layer that provides heat-sealing properties to the exterior film 50. Examples of the heat-sealable resin layer 53 include resin films made of polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polyolefin resins such as polyethylene resins and polypropylene resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. From the standpoints of sealability and strength, the thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm.

[0043] The exterior film 50 preferably has one or more layers having a buffer function (hereinafter referred to as "buffer layer") outside the heat-sealable resin layer 53, more preferably outside the barrier layer 52. The buffer layer may be laminated on the outside of the base material layer 51, or the base material layer 51 may also function as a buffer layer. When the exterior film 50 has multiple buffer layers, the multiple buffer layers may be adjacent to each other, or may be laminated with the base material layer 51, the barrier layer 52, or the like interposed therebetween.

[0044] 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.

[0045] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 1 mm, more preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5 mm, and even more preferably 2 mm. When the buffer layer is made of rubber, the preferred ranges of the buffer layer thickness are 1 mm to 10 mm, 1 mm to 5 mm, 1 mm to 2 mm, 0.5 mm to 10 mm, 0.5 mm to 5 mm, and 0.5 mm to 2 mm.

[0046] When the exterior film 50 has a buffer layer, the buffer layer functions as a cushion, thereby preventing the exterior film 50 from being damaged by impact when the energy storage device 10 is dropped or by handling during manufacturing of the energy storage device 10.

[0047] The lid body 60 shown in Fig. 4 has, for example, a rectangular parallelepiped shape and is, for example, a resin molded product made of a resin material. The lid body 60 may be formed by, for example, cold forming the exterior film 50, or may be a metal molded product. The material constituting the lid body 60 may include at least two or more materials selected from a metal oxide, a carbon material, and a rubber material. The lid body 60 may include a metal oxide, a carbon material, and a rubber material.

[0048] The lid 60 is preferably made up of a resin material. Here, "made up of a resin material" means that, when the entire material constituting the lid 60 is taken as 100% by mass, the content of the resin material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In other words, the material constituting the lid 60 can contain materials other than the resin material in addition to the resin material.

[0049] Specific examples of the resin include thermoplastic resins such as polyester, polyolefin, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, as well as modified versions of these resins. The resin material may be a mixture of these resins, a copolymer, or a modified version of the copolymer. Among these, the resin material is preferably a heat-sealable resin such as polyester or polyolefin, and more preferably polyolefin. When the resin material is a resin, the lid 60 may be molded by any molding method.

[0050] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters whose repeating units are primarily ethylene terephthalate. Specific examples include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), and polyethylene (terephthalate / decanedicarboxylate). Among these, polybutylene terephthalate is preferred as the resin material from the viewpoint of enhancing heat resistance and pressure resistance.

[0051] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylenes such as homopolypropylene, polypropylene block copolymers (e.g., block copolymers of propylene and ethylene), and polypropylene random copolymers (e.g., random copolymers of propylene and ethylene); propylene-α-olefin copolymers; and ethylene-butene-propylene terpolymers. When the polyolefin resin is a copolymer, it may be a block copolymer or a random copolymer. Among these, polypropylene is preferred as the resin material because of its excellent heat-sealing properties and electrolyte resistance.

[0052] The resin as the resin material may contain a filler as needed. Specific examples of the filler include glass beads, graphite, glass fiber, and carbon fiber. By including the filler in the resin as the resin material, the deformation resistance of the lid 60 against temperature changes can be improved.

[0053] The melt mass flow rate of the resin material contained in the material constituting the lid body 60 is preferably in the range of 1 g / 10 min to 80 g / 10 min, and more preferably in the range of 5 g / 10 min to 60 g / 10 min. The melt mass flow rate is measured based on JIS K7210-1:2014.

[0054] The lid 60 may be configured to contain a conductive material. "Containing a conductive material" means that, when the entire material constituting the lid 60 is taken as 100% by mass, the content of the conductive material is 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. In other words, the material constituting the lid 60 can contain, in addition to the conductive material, a material other than the conductive material.

[0055] The conductive material constituting the lid body 60 is, for example, a metal material. The metal material constituting the lid body 60 is, for example, aluminum, aluminum alloy, nickel, copper, or copper alloy. For example, when the electrode body 20 is a lithium-ion battery, the lid body 60 connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The lid body 60 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the lid body 60 connected to the negative electrode may be copper plated with nickel. The material constituting the lid body 60 may include recycled metal material. When the lid body 60 is made of a conductive material, the lid body 60 also functions as the electrode terminal 30. Since the electrode terminal 30 can be omitted from the electricity storage device 10, the configuration of the electricity storage device 10 can be simplified.

[0056] When the lid 60 contains a conductive material, the lid 60 may be bonded to the exterior film 50 via an adhesive film. Any adhesive film can be selected as long as it can bond the exterior film 50 and the lid 60 together. The adhesive film is preferably a laminated film having at least a heat-sealable resin layer, a heat-resistant substrate layer, and a heat-sealable resin layer in this order. The specifications for the heat-sealable resin layer of the adhesive film are the same as those for the heat-sealable resin layer 53. The materials constituting the heat-sealable resin layers on both sides of the adhesive film may be the same or different, and are appropriately selected according to the materials constituting the heat-sealable resin layer 53 of the exterior film 50 and the materials constituting the lid 60. The material constituting the heat-sealable resin layer of the adhesive film on the side bonded to the lid 60 is preferably an acid-modified polyolefin resin graft-modified with an acid such as maleic anhydride. The heat-sealable resin layer of the adhesive film on the side that is bonded to the exterior film 50 is preferably made of the same type of material as the material that constitutes the heat-sealable resin layer 53 of the exterior film 50 .

[0057] The heat-resistant substrate layer may be any film made of a heat-resistant resin, such as a non-stretched or stretched film of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polymethylpentene (registered trademark), polyacetal cyclic polyolefin, polyethylene, polypropylene, etc. Polyethylene terephthalate is particularly preferred because it is inexpensive and has high strength.

[0058] The adhesive film preferably has adhesive properties. When the second sealing portion 80 (described later) is formed with the adhesive film disposed between the exterior film 50 and the lid 60, the adhesive film is less likely to shift position relative to the lid 60 and the exterior film 50. By incorporating a tackifier resin into the heat-sealable resin layer of the adhesive film, adhesive properties can be imparted to the adhesive film. Examples of the tackifier resin include amorphous polyolefins. Examples of amorphous polyolefins include amorphous polypropylene and copolymers of amorphous propylene and other α-olefins. The content of the tackifier resin relative to the base material constituting the heat-sealable resin is preferably 10 to 20% by weight or less.

[0059] The lid 60 has a first surface 61, a second surface 62, and a sealing surface 63. The first surface 61 faces the electrode body 20. The second surface 62 is the surface opposite to the first surface 61. The sealing surface 63 is connected to the first surface 61 and the second surface 62, and is joined to the heat-sealable resin layer 53 of the exterior film 50.

[0060] The sealing surface 63 includes a first sealing surface 63A, a second sealing surface 63B, a third sealing surface 63C, and a fourth sealing surface 63D. The first sealing surface 63A constitutes the upper surface of the lid body 60. The first sealing surface 63A extends in a first direction (the LR direction in this embodiment) when viewed from the front of the lid body 60. The second sealing surface 63B and the third sealing surface 63C are connected to the first sealing surface 63A and constitute the side surfaces of the lid body 60. The second sealing surface 63B and the third sealing surface 63C extend in a second direction (the UD direction in this embodiment) that intersects with the first direction when viewed from the front of the lid body 60. In this embodiment, the first direction and the second direction are orthogonal when viewed from the front of the lid body 60. The first direction and the second direction do not have to be orthogonal when viewed from the front of the lid body 60. The fourth sealing surface 63D constitutes the lower surface of the lid body 60. The fourth sealing surface 63D extends in a first direction (the LR direction in this embodiment) when the lid 60 is viewed from the front.

[0061] When the lid body 60 is plate-shaped, it is preferable that the lid body 60 have a certain thickness so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is placed on top of it. From another perspective, when the lid body 60 is plate-shaped, it is preferable that the sealing surface 63 of the lid body 60 have a certain thickness so that the sealing surface 63 of the lid body 60 and the exterior film 50 can be suitably heat-sealed when forming the second sealing portion 80 described below. The minimum thickness of the lid body 60 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 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum thickness of the lid body 60 may be 20 mm or more. Preferred ranges for the thickness of the material constituting the lid body 60 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 embodiment, when the lid body 60 is described as being plate-shaped, this does not include embodiments in which the lid body 60 is composed solely of a film as defined by the JIS (Japanese Industrial Standards) [Packaging Terminology] standard. The thickness of the lid body 60 may vary depending on the region of the lid body 60. When the thickness of the lid body 60 varies depending on the region, the thickness of the lid body 60 is the thickness of the thickest portion.

[0062] The cover 60 further includes boundaries 64, 65, 66, and 67. The boundary 64 is the boundary between the first seal surface 63A and the second seal surface 63B. The boundary 65 is the boundary between the first seal surface 63A and the third seal surface 63C. The boundary 66 is the boundary between the fourth seal surface 63D and the second seal surface 63B. The boundary 67 is the boundary between the fourth seal surface 63D and the third seal surface 63C. The shapes of the boundaries 64 to 67 may be angular, or may be rounded by applying a rounding process. In this embodiment, the boundaries 64 to 67 are angular.

[0063] From the viewpoint of appropriately heat-sealing the lid 60 and the exterior film 50 together, it is preferable that the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 of the exterior film 50 are primarily made of the same material. In this embodiment, examples of the material constituting the lid 60 include polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polyolefin resins such as polyethylene resins, fluorine-based resins and polypropylene resins, cyclic polyolefin resins, and acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. From the viewpoint of appropriately heat-sealing the lid 60 and the exterior film 50 together, it is preferable that the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 of the exterior film 50 are primarily made of the same material. In this embodiment, the main material of the lid 60 and the heat-sealable resin layer 53 is, for example, a polyolefin resin such as a polyethylene resin or a polypropylene resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The main material refers to, for example, a material that accounts for 50% or more of the materials contained in the constituent elements.

[0064] In the present embodiment, a through hole 60X into which the electrode terminal 30 is inserted is formed in the lid body 60. The through hole 60X penetrates the first surface 61 and the second surface 62. When the electrode body 20 is wrapped in the exterior film 50, the electrode terminal 30 passes through the through hole 60X formed in the lid body 60 and protrudes to the outside of the exterior body 40. A small gap between the through hole 60X of the lid body 60 and the electrode terminal 30 is filled with, for example, resin. Note that, in the energy storage device 10, the position from which the electrode terminal 30 protrudes to the outside can be selected arbitrarily. For example, the electrode terminal 30 may protrude to the outside from a hole formed in any one of the six surfaces of the exterior body 40. In this case, a small gap between the exterior body 40 and the electrode terminal 30 is filled with, for example, resin. In another example, the electrode terminal 30 may protrude to the outside of the exterior body 40 from between the sealing surface 63 of the lid body 60 and the exterior film 50. In this case, the through-hole 60X does not have to be formed in the lid body 60. In the electricity storage device 10, the lid body 60 and the electrode terminal 30 are provided as separate bodies, but the lid body 60 and the electrode terminal 30 may be formed integrally. Note that, even if the electrode terminal 30 does not protrude from the edge of the exterior body 40, the lid body 60 does not have to have the through-hole 60X.

[0065] In this embodiment, the first sealing portion 70 is formed by wrapping the exterior film 50 around the electrode body 20 so as to have an opening 40A, and then heat-sealing the opposing surfaces of the exterior film 50 (heat-fusible resin layer 53) together.

[0066] The first sealed portion 70 is formed by heat-sealing a portion of the exterior film 50 shown in FIG. 3 including the first edge 50A and a portion of the exterior film 50 including the second edge 50B. The first sealed portion 70 extends in the longitudinal direction (FB direction) of the exterior body 40. The position at which the first sealed portion 70 is formed on the exterior body 40 can be selected arbitrarily. In this embodiment, the base 70X of the first sealed portion 70 is preferably located on the edge 43 at the boundary between the first surface 41 and the second surface 42 of the exterior body 40. The first surface 41 has a larger area than the second surface 42. The base 70X of the first sealed portion 70 may be located on any surface of the exterior body 40. In this embodiment, the first sealed portion 70 protrudes outward beyond the electrode assembly 20 in a plan view. The first sealed portion 70 may be folded, for example, toward the second surface 42 or the first surface 41 of the exterior body 40.

[0067] If an abnormality occurs in the electrode assembly 20, gas may be generated inside the exterior body 40. If the electricity storage device 10 is a lithium ion battery, gases such as volatile organic solvents, carbon monoxide, carbon dioxide, methane, ethane, hydrogen, and hydrogen fluoride may be generated inside the exterior body 40 due to the evaporation and decomposition of the organic solvent in the electrolyte. If the electricity storage device 10 is a capacitor, gas may be generated inside the exterior body 40 due to a chemical reaction in the capacitor. If the electricity storage device 10 is an all-solid-state battery, the electrode assembly 20 may include a solid electrolyte that can generate gas. For example, if the solid electrolyte is sulfide-based, hydrogen sulfide gas may be generated. If gas is generated inside the exterior body 40, the internal pressure of the exterior body 40 increases. For this reason, it is necessary to vent the gas generated inside the exterior body 40 to the outside of the exterior body 40.

[0068] Furthermore, the manufacturing process of the electricity storage device 10 preferably includes a step (hereinafter referred to as an “aging step”) of aging the electricity storage device 10 in a temporarily sealed state for a predetermined time in a predetermined temperature environment for the purpose of, for example, permeating the electrolyte solution into the electrode body 20. In the aging step, gas is generated from the electrode body 20, and it is therefore necessary to discharge the generated gas to the outside of the exterior body 40.

[0069] From this perspective, in this embodiment, the electricity storage device 10 includes a check valve 90 so that gas generated inside the exterior body 40 can be discharged to the outside of the exterior body 40. The check valve 90 can be a known valve type that allows repeated gas release, such as a ball spring type, poppet type, duckbill type, umbrella type, or diaphragm type. In this embodiment, the check valve 90 is attached to the first sealing portion 70.

[0070] 5 is a front view of the check valve 90 of this embodiment. The check valve 90 includes a housing 91, a valve mechanism 92, and an attachment portion 93. The housing 91 is made of, for example, metal or resin. The housing 91 is, for example, cylindrical and houses the valve mechanism 92 therein. An outlet 91A for discharging gas is formed on the end face of the housing 91 opposite the attachment portion 93. When the check valve 90 is disposed in the first sealing portion 70, the housing 91 is located outside the first sealing portion 70. The housing 91 may be joined to the exterior film 50 by any means, for example.

[0071] The valve mechanism 92 includes a spring, a valve body, and a valve seat. That is, in this embodiment, the check valve 90 is a ball spring type check valve.

[0072] The attachment portion 93 is connected to the housing 91. The attachment portion 93 is made of metal or resin. The attachment portion 93 may be integral with the housing 91, or may be formed separately from the housing 91 and joined to the housing 91. The attachment portion 93 is sandwiched between the opposing surfaces (thermally adhesive resin layers 53) of the exterior film 50 that form the first sealing portion 70. When the attachment portion 93 is made of metal, the attachment portion 93 and the exterior film 50 are preferably joined via an adhesive film that adheres well to both metal and resin. The attachment portion 93 has, for example, a cylindrical shape. From the viewpoint of suitably joining the attachment portion 93 and the exterior film 50, the outer diameter of the attachment portion 93 is preferably smaller than the outer diameter of the housing 91.

[0073] An inlet 93A facing the inside of the exterior body 40 is formed on the end face of the attachment portion 93 opposite to the housing 91. When gas is generated inside the exterior body 40 and the internal pressure of the exterior body 40 exceeds the valve opening pressure of the valve mechanism 92, the valve mechanism 92 opens. When the valve mechanism 92 opens, the gas passes through the inlet 93A, the inside of the attachment portion 93, the inside of the housing 91, and the outlet 91A in that order, and is then discharged to the outside.

[0074] In this embodiment, the second sealing portion 80 is formed by heat-sealing the heat-sealable resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid 60. Hereinafter, the seal strength between the heat-sealable resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid 60 may be referred to as the seal strength of the second sealing portion 80. The seal strength of the second sealing portion 80 is the seal strength between the heat-sealable resin layer 53 and the lid 60 at the long side portion of the sealing surface 63, i.e., the sealing surface 63 extending in the LR direction (see FIG. 1A ).

[0075] The seal strength of the second sealing portion 80 is measured as follows. First, a slit is formed in the portion of the exterior film 50 that constitutes the first surface 41 of the exterior body 40, and three strip-shaped members 41X, 41Y, and 41Z (see the two-dot chain lines in FIG. 1B ) are formed aligned in the LR direction. Note that in the second and subsequent embodiments and modified examples described below, the strip-shaped members 41X, 41Y, and 41Z are formed so as to avoid the check valve and the open valve. The width of the three strip-shaped members 41X, 41Y, and 41Z in the LR direction is 15 mm. The ends of the strip-shaped members 41X, 41Y, and 41Z are joined to the lid body 60 at the second sealing portion 80. The length of the lid body 60 in the LR direction is 45 mm or more. Next, the seal strength of each of the strip-shaped members 41X, 41Y, and 41Z is measured by pulling the end opposite the end joined to the lid 60 upward in the UD direction (the direction opposite the first surface 41B). In this embodiment, the seal strength of the second sealing portion 80 is the average value of the seal strengths of the strip-shaped members 41X, 41Y, and 41Z. When the lid 60 has a length in the LR direction of less than 45 mm, three strip-shaped members with an arbitrary width X mm, less than 15 mm, are formed, and the seal strengths of the three strip-shaped members are measured in the same manner as when the lid 60 has a length in the LR direction of 45 mm or more. The obtained seal strengths are each divided by the arbitrary width X mm and multiplied by 15 to convert them to the seal strengths of the three strip-shaped members in a 15 mm width. The seal strength of the second sealing portion 80 is the average value of the seal strengths of the three strip-shaped members converted to a 15 mm width. In addition, when the lid body 60 is divided into multiple parts including long sides and short sides, the sealing strength of the second sealing portion 80 is the sealing strength of the long side portions of the sealing surfaces 63 of the multiple parts.

[0076] From the viewpoint of suitably maintaining the state in which the electrode assembly 20 is sealed by the exterior body 40, the seal strength of the second sealing unit 80 is preferably 40 N / 15 mm or more, more preferably 50 N / 15 mm or more, even more preferably 60 N / 15 mm or more, even more preferably 70 N / 15 mm or more, and even more preferably 85 N / 15 mm or more. When the seal strength of the second sealing unit 80 is 40 N / 15 mm or more, the state in which the electrode assembly 20 is sealed by the exterior body 40 is suitably maintained even after the power storage device 10 has been used for, for example, several years (less than 10 years). When the seal strength of the second sealing unit 80 is 85 N / 15 mm or more, the state in which the electrode assembly 20 is sealed by the exterior body 40 is suitably maintained even after the power storage device 10 has been used for, for example, 10 years or more. The seal strength of the second sealing unit 80 is preferably 300 N / 15 mm or less. A preferred range for the seal strength of the second sealing portion 80 is 40N / 15mm to 300N / 15mm, 50N / 15mm to 300N / 15mm, 60N / 15mm to 300N / 15mm, 70N / 15mm to 300N / 15mm, or 85N / 15mm to 300N / 15mm.

[0077] 6 is a flowchart showing an example of a method for manufacturing the power storage device 10. The method for manufacturing the power storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, a fifth step, a sixth step, a seventh step, and an eighth step. The first step to the eighth step are performed, for example, by a manufacturing apparatus for the power storage device 10. Note that the first step to the eighth step are names of the steps in the method for manufacturing the power storage device 10 defined for convenience, and do not necessarily indicate the order of the steps.

[0078] In the first process of step S11, the manufacturing equipment joins the lid body 60 and the electrode terminal 30. By completing the second process, a pair of lid units 60Z in which the electrode terminal 30 is joined to the lid body 60 is completed.

[0079] The second step of step S12 is performed after the first step. In the second step, the manufacturing apparatus places a pair of lid units 60Z on the sides of the electrode body 20 and joins the electrode terminals 30 to the electrode body 20. Note that the manufacturing method for the electricity storage device 10 may include, instead of the first and second steps, a step of first joining the electrode body 20 to the electrode terminals 30 and then joining the lid body 60 to the electrode terminals 30 joined to the electrode body 20.

[0080] The third step of step S13 is performed after the second step. In the third step, the manufacturing apparatus wraps the exterior film 50 around the electrode assembly 20 and the lid body 60. In the third step, the manufacturing apparatus wraps the exterior film 50 around the electrode assembly 20 and the lid body 60 while tension is applied to the exterior film 50, while restricting the movement of the electrode assembly 20 and the lid body 60 using a restricting means. The restricting means is, for example, a groove into which the electrode assembly 20 and the lid body 60 are fitted. The restricting means may be a device that applies an external force to the electrode assembly 20 and the lid body 60 to prevent the electrode assembly 20 and the lid body 60 from moving. The restricting means may be a device that applies a force to the electrode assembly 20 and the lid body 60 in a direction opposite to the direction in which the exterior film 50 is pulled. The restricting means may include a roller that runs on the exterior film 50 while the exterior film 50 is being pulled in order to remove wrinkles in the exterior film 50.

[0081] The fourth step of step S14 is performed after the third step. In the third step, the manufacturing apparatus arranges the check valve 90 in a portion of the exterior film 50 where the first sealing portion 70 is to be formed.

[0082] The fifth step of step S15 is performed after the fourth step. In the fifth step, the manufacturing equipment forms a first sealed portion (hereinafter referred to as a "temporary first sealed portion") having an unsealed portion formed in a part thereof for injecting an electrolyte solution. In the temporary first sealed portion, the heat-sealable resin layers 53 of the exterior film 50 facing each other and the mounting portion 93 of the check valve 90 are joined. Note that if the electricity storage device 10 is, for example, an all-solid-state battery, the step of injecting an electrolyte solution is not necessary, and therefore, in the fifth step, the manufacturing equipment forms the first sealed portion 70 in which the check valve 90 is disposed.

[0083] The sixth step of step S16 is performed after the fifth step. In the sixth step, the manufacturing apparatus heat-seals the heat-fusible resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid 60 to form the second sealing portion 80.

[0084] The seventh step of step S17 is performed after the sixth step. In the seventh step, the manufacturing equipment injects an electrolyte solution through the unsealed portion formed in the temporary first sealing portion.

[0085] The eighth step of step S18 is performed after the seventh step is completed. In the eighth step, the manufacturing apparatus heat-seals a portion of the temporary first sealed portion, including the unsealed portion, to form the first sealed portion 70. If the check valve 90 is not provided in the fifth step, the check valve 90 may be provided in the first sealed portion 70 in the eighth step. Note that if the power storage device 10 is, for example, an all-solid-state battery, the seventh and eighth steps are omitted. After the eighth step, an aging step is performed. Gas generated in the aging step is discharged to the outside via the check valve 90.

[0086] <1-3. Effects of the Electricity Storage Device> The electricity storage device 10 includes the check valve 90, and therefore, gas generated inside the exterior body 40 can be discharged to the outside.

[0087] Furthermore, when manufacturing an electricity storage device that does not have a check valve (hereinafter referred to as a "virtual electricity storage device"), it is necessary to form a gas pocket to store the gas generated during the aging process. The gas pocket includes the temporary first sealing portion 70 as well as an extended portion of the exterior film 50. The portion of the exterior film 50 that extends beyond the first sealing portion 70 is cut off after the aging process is completed. For this reason, the virtual electricity storage device requires an exterior film 50 that is larger in size than the exterior film 50 included in the finished virtual electricity storage device.

[0088] On the other hand, in the electricity storage device 10, the check valve 90 is disposed in the fourth step, and therefore the gas generated in the aging step is discharged via the check valve 90. Therefore, in the electricity storage device 10, it is not necessary to form a gas pocket for storing the gas generated in the aging step. In the electricity storage device 10, the portion of the exterior film 50 that is discarded is small, and therefore the manufacturing cost can be reduced.

[0089] Furthermore, in the hypothetical electricity storage device, a portion of the first sealed portion 70 corresponding to the base 70X is heat-sealed to form a gas pocket. After the aging process is completed, the portion of the base 70X that was heat-sealed when the gas pocket was formed is heat-sealed again to form the first sealed portion 70. In this way, in the hypothetical electricity storage device, a portion of the base 70X is heat-sealed multiple times, reducing the strength of the base 70X. Therefore, for example, when the first sealed portion 70 is folded toward the first surface 41 or the second surface 42, the base 70X of the first sealed portion 70 may be damaged, resulting in leakage of the electrolyte or the like.

[0090] On the other hand, because the check valve 90 in the electricity storage device 10 allows gas to be discharged, the unsealed portion of the temporary first sealed portion formed in the fifth step only needs to be large enough to allow the injection of the electrolyte. Therefore, the area that is heat-sealed when forming the first sealed portion 70 in the eighth step may be a small area that includes the unsealed portion of the temporary first sealed portion. In the electricity storage device 10, the area of ​​the first sealed portion 70 that is heat-sealed multiple times is small, so the strength of the base 70X of the first sealed portion 70 is less likely to decrease. Therefore, even when the first sealed portion 70 in the electricity storage device 10 is folded toward the first surface 41 or the second surface 42, damage to the base 70X can be suppressed.

[0091] Furthermore, because the gas pocket is mobile, there is a risk that a portion including the base may be damaged due to material fatigue or when an external force such as bending or pulling is applied. The base of the gas pocket coincides with the base 70X of the first sealing portion 70. As described above, the electricity storage device 10 can discharge gas using the check valve 90, so it is not necessary to form a gas pocket during manufacturing. This makes it possible to prevent damage to the base 70X of the first sealing portion 70.

[0092] 2. Second Embodiment An electricity storage device 200 of the second embodiment differs from the electricity storage device 10 of the first embodiment in the location where the check valve 90 is disposed, but other configurations are similar to those of the electricity storage device 10 of the first embodiment. The electricity storage device 200 of the second embodiment will be described below, focusing on the differences from the electricity storage device 10 of the first embodiment.

[0093] 2-1. Configuration of the Power Storage Device Fig. 7 is a perspective view schematically showing a power storage device 200 according to a second embodiment. Fig. 8 is a cross-sectional view taken along line D8-D8 in Fig. 7.

[0094] In the power storage device 200, the check valve 90 is attached to the lid body 60. The check valve 90 and the lid body 60 constitute a lid unit 260Z. The lid unit 260Z is manufactured, for example, by injection molding the material that constitutes the lid body 60 onto the check valve 90 placed in a mold, i.e., by insert molding. In another example, a hole is formed in the lid body 60, and the mounting portion 93 of the check valve 90 is inserted into the hole.

[0095] In the present embodiment, at least a portion of the mounting portion 93 of the check valve 90 is embedded inside the lid 60. Note that at least a portion of the housing 91 may be embedded inside the lid 60. The position of the inlet 93A of the mounting portion 93 can be selected arbitrarily. The inlet 93A may be located on the first surface 61 of the lid 60, may be located closer to the electrode assembly 20 than the first surface 61 of the lid 60, or may be located inside the lid 60. From the viewpoint of suppressing interference between the check valve 90 and the electrode assembly 20, it is preferable that the inlet 93A be as far away from the electrode assembly 20 as possible. In the example shown in FIG. 8 , the inlet 93A is located on the first surface 61 of the lid 60.

[0096] In the power storage device 200, the check valves 90 may be attached to one of the lid bodies 60 and the other lid body 60. In this case, the valve opening pressure of the check valve 90 attached to one of the lid bodies 60 is preferably lower than the valve opening pressure of the check valve 90 attached to the other lid body 60. Gas generated inside the exterior body 40 is discharged from the check valve 90 attached to one of the lid bodies 60 before the check valve 90 attached to the other lid body 60. This allows the location from which the gas is discharged to be limited.

[0097] In another example, in the power storage device 200, the check valve 90 may be attached to only one of the lid bodies 60 and the other lid body 60. In other words, the check valve 90 is not attached to the other lid body 60. In this case, the location from which the gas is discharged can be limited.

[0098] <2-2. Effects of the Power Storage Device> According to the power storage device 200, the same effects as those of the power storage device 10 of the first embodiment can be obtained.

[0099] 3. Third Embodiment An electricity storage device 300 of the third embodiment differs from the electricity storage device 10 of the first embodiment in that it includes a first sealing portion 370 and in the location where a check valve 90 is disposed, but other configurations are similar to those of the electricity storage device 10 of the first embodiment. The electricity storage device 300 of the third embodiment will be described below, focusing on the parts that differ from the electricity storage device 10 of the first embodiment.

[0100] 3-1. Configuration of the Electricity Storage Device Fig. 9 is a perspective view that schematically shows an electricity storage device 300 according to a third embodiment. Fig. 10 is a cross-sectional view that shows an example of the layer configuration of an exterior film 50 that the electricity storage device 10 includes.

[0101] The electricity storage device 300 includes a first sealed portion 370. The first sealed portion 370 is a portion that is sealed by joining the outermost layer and the innermost layer of the exterior film 50 in a state where the exterior film 50 is wrapped around the electrode body 20.

[0102] As shown in FIG. 10 , in this embodiment, the exterior film 50 preferably has a heat-sealable resin layer 56 laminated on the substrate layer 51 opposite the barrier layer 52. The heat-sealable resin layer 56 is bonded to the substrate layer 51 via, for example, an adhesive layer 57. In the example shown in FIG. 10 , the exterior film 50 has the heat-sealable resin layer 56 as its outermost layer and the heat-sealable resin layer 53 as its innermost layer, thereby suitably forming the first sealing portion 370. Even when the exterior film 50 has the heat-sealable resin layer 56 as its outermost layer and the heat-sealable resin layer 53 as its innermost layer, the heat-sealable resin layer 53 and the heat-sealable resin layer 56 may be bonded together with an adhesive or the like. When the exterior film 50 has the layer configuration shown in FIG. 2 , the exterior film 50 has the substrate layer 51 as its outermost layer and the heat-sealable resin layer 53 as its innermost layer. Therefore, when the exterior film 50 has the layer structure shown in Fig. 2, the outermost layer and the innermost layer may be joined together, for example, with an adhesive. In the example shown in Fig. 10, at least the base material layer 51 may be omitted.

[0103] The position of the second edge 50B of the exterior film 50 can be selected arbitrarily when the exterior film 50 is wrapped around the electrode body 20. The second edge 50B may be located on the first surface 41 of the exterior body 40, on the second surface 42, or on the side 43 at the boundary between the first surface 41 and the second surface 42.

[0104] In this embodiment, the check valve 90 is disposed in the first sealing portion 370. The attachment portion 93 of the check valve 90 is joined to the exterior film 50 in a state where it is sandwiched between the outermost layer and the innermost layer of the exterior film 50.

[0105] <3-2. Effects of the Electricity Storage Device> The electricity storage device 300 includes the check valve 90, and therefore, gas generated inside the exterior body 40 can be discharged to the outside.

[0106] Since there is no need to form gas pockets during the manufacturing of the electricity storage device 300, it is possible to prevent the formation of portions with low strength in the exterior body 40.

[0107] [4. Fourth Embodiment] The power storage device 400 of the fourth embodiment differs from the power storage device 10 of the first embodiment in that it includes opening valves 491 and 492, but other configurations are similar to those of the power storage device 10 of the first embodiment. The following describes the power storage device 400 of the fourth embodiment, focusing on the differences from the power storage device 10 of the first embodiment.

[0108] 4-1. Configuration of the Electricity Storage Device FIG. 11 is a perspective view schematically illustrating an electricity storage device 400 according to a fourth embodiment. The electricity storage device 400 includes open valves 491 and 492. The open valves 491 and 492 are films that release gas by peeling or cohesive failure when gas is generated inside the exterior body 40 and the internal pressure of the exterior body 40 increases. The material forming the open valves 491 and 492 can be selected arbitrarily as long as it can function as an open valve. For example, the materials exemplified for the adhesive film 31 can be used as the material forming the open valves 491 and 492. The material forming the open valves 491 and 492 preferably includes at least one resin layer having a melting peak temperature at least 5°C lower than that of the heat-sealable resin layer 53 of the exterior film 50. The adhesive film preferably includes at least one resin layer having a melting peak temperature at least 100°C and not more than 135°C.

[0109] The opening valves 491 and 492 are arranged at any positions in the exterior body 40 where gas generated inside the exterior body 40 can be discharged. In the present embodiment, the opening valve 491 is arranged in the first sealing portion 70. The opening valve 492 is arranged in the second sealing portion 80. One of the opening valves 491 and 492 may be omitted.

[0110] The opening valve 491 is bonded to the opposing heat-sealable resin layers 53 of the exterior film 50. When the internal pressure of the exterior body 40 increases, the opening valve 491 peels off from at least one of the opposing heat-sealable resin layers 53, forming an opening in the first sealed portion 70. Gas generated inside the exterior body 40 passes through the opening formed in the first sealed portion 70 and is discharged to the outside.

[0111] The open valve 492 is disposed between the heat-sealable resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid 60, in other words, in the second sealing portion 80. The open valve 492 is bonded to the heat-sealable resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid 60. When the internal pressure of the exterior body 40 increases, the open valve 492 peels off from at least one of the heat-sealable resin layer 53 and the sealing surface 63 of the lid 60, forming an opening in the second sealing portion 80. Gas generated inside the exterior body 40 passes through the opening formed in the second sealing portion 80 and is discharged to the outside. The open valve 492 and the lid 60 constitute a lid unit 460Z. The manufacturing method for the electricity storage device 400 of the fourth embodiment preferably includes a step of forming a gas pocket that stores gas generated by the aging step. When a check valve 90 is arranged in the first sealing portion 70, the second sealing portion 80, or the lid body 60 of the electricity storage device 400, the process of forming a gas pocket is not necessary in the manufacturing method of the electricity storage device 400 of the fourth embodiment.

[0112] In the power storage device 400, the open valve 492 may be disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 and the second sealing portion 80 corresponding to the other lid body 60. In this case, the open pressure of the open valve 492 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 is preferably lower than the open pressure of the open valve 492 disposed in the second sealing portion 80 corresponding to the other lid body 60. Gas generated inside the exterior body 40 is discharged from the open valve 492 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 before the open valve 492 disposed in the second sealing portion 80 corresponding to the other lid body 60. This allows the location from which the gas is discharged to be limited. Furthermore, even if gas continues to be generated inside the exterior body 40 after the open valve 492 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 is peeled off, the gas can be discharged by peeling off the open valve 492 disposed in the second sealing portion 80 corresponding to the other lid body 60.

[0113] The opening pressure of the opening valve 492 is defined as follows. A virtual electricity storage device 10 is prepared in which the electrode assembly 20 and the other lid body 60 are omitted from the electricity storage device 400. An air supply jig is attached to any one of the pair of first surfaces 41 and the pair of second surfaces 42 of the virtual electricity storage device. A fixing jig is placed on the pair of first surfaces 41 and the pair of second surfaces 42 of the virtual electricity storage device with the air supply jig attached, and the virtual electricity storage device is fixed. Air is supplied from the air supply jig into the interior of the exterior body. The pressure when the opening valve 492 arranged in the second sealing portion 80 corresponding to one of the lid bodies 60 is peeled off and gas is discharged is the opening pressure of the opening valve 492. Note that if the virtual electricity storage device 400 includes a check valve and an opening valve other than the opening valve 492, the opening pressure is measured with the valves other than the opening valve 492, which is the target of opening pressure measurement, closed. The opening pressure of the opening valve 492 arranged in the second sealing portion 80 corresponding to the other lid body 60 can be determined in a similar manner using a virtual energy storage device 10 in which the electrode body 20 and one of the lid bodies 60 are omitted from the energy storage device 400.

[0114] In another example, in the power storage device 200, the open valve 492 may be arranged only in the second sealing portion 80 that corresponds to one of the lid bodies 60 of the second sealing portion 80. In other words, the open valve 492 is not arranged in the second sealing portion 80 that corresponds to the other lid body 60. In this case, the location from which the gas is discharged can be limited.

[0115] <4-2. Effects of the Electricity Storage Device> The electricity storage device 400 includes the opening valves 491, 492, and therefore, if gas is generated inside the exterior body 40 due to an abnormality in the electrode body 20, for example, the gas can be discharged to the outside.

[0116] [5. Modifications] The above-described embodiments are examples of possible forms of the electricity storage device and lid unit according to the present invention, and are not intended to limit the forms. The electricity storage device and lid unit according to the present invention may take forms different from those exemplified in the embodiments. Examples of such forms include forms in which part of the configuration of each embodiment is replaced, modified, or omitted, or forms in which a new configuration is added to each embodiment. Below are some examples of modifications of each embodiment. Note that the following modifications can be combined with each other as long as there is no technical contradiction.

[0117] <5-1> In the first embodiment, the check valve 90 may be a non-permeable gas-venting film that is permeable to gas but not to moisture. The non-permeable gas-venting film may be composed of a laminate including at least a substrate layer and an adhesive layer. The non-permeable gas-venting film preferably has a water vapor transmission rate of 10 cc / m or less when left standing in an environment of 60°C and 90% RH for 48 hours. 2 / day or less, more preferably 5cc / m 2 / day or less, more preferably 2 cc / m 2 / day or less, more preferably 0 cc / m 2 The water vapor transmission rate of the non-water-permeable gas-venting film is measured as follows.

[0118] <Water vapor permeability> Water vapor permeability is measured in an environment of 60°C and 90% RH according to the cup method of JIS Z 0208. A test piece is cut out of a sample to a size of 75 mmφ, and three 5 mmφ holes are drilled 5 mm inward from the outer periphery and set in a jig using a screw-fastening type. A cup with a permeation area of ​​60 mmφ is used.

[0119] In order to achieve the desired performance, the non-water-permeable gas-permeable film preferably has a carbon dioxide permeability of 5000 cm 3 / (m 2 24h atm) or more, more preferably 8000 cm 3 / (m 2 24h atm) or more, more preferably 10,000 cm 3 / (m 2The upper limit of the carbon dioxide permeability of the non-water-permeable gas-permeable film 1 of the present disclosure is, for example, 100,000 cm 3 / (m 2 The carbon dioxide permeability of the non-water-permeable gas-exhausting film is measured as follows.

[0120] <Carbon dioxide permeability> The carbon dioxide permeability of the film was measured under the following conditions in accordance with the test items: gas permeability and gas permeability coefficient (differential pressure method) specified in JIS K 7126-1:2006. Detector: gas chromatograph (thermal conductivity detector (TDC)) Gas: carbon dioxide (CO2) (humidified atmosphere) Temperature and humidity: 60±2°C, 50±5% RH Differential pressure: 1 atm (partial pressure at 60°C, 50% RH (gas: 68.52 cmHg, water vapor: 7.48 cmHg) Permeation area: 15.2 × 10 -4 m 2 (Transmission part diameter φ4.4 x 10 -2 m) Number of tests: n = 1 Measuring device: Differential pressure gas / vapor permeability measuring device

[0121] In order to achieve the desired effect, the non-water-permeable gas-permeable film preferably has an oxygen permeability of 50 cm 3 / (m 2 24h atm) or more, more preferably 100 cm 3 / (m 2 24h atm) or more, more preferably 200 cm 3 / (m 2 The upper limit of the oxygen transmission rate of the non-water-permeable gas-permeable film of the present disclosure is, for example, 100,000 cm 3 / (m 2 The oxygen permeability of the non-water-permeable gas-venting film 1 is measured as follows.

[0122] <Oxygen Permeability> Oxygen permeability can be measured using an oxygen gas permeability measuring device under conditions of a temperature of 40°C and a humidity of 90% RH in accordance with JIS K7126-2:2006 (Plastics - Films and Sheets - Gas Permeability Testing Methods - Part 2: Isobaric Method, Appendix A: Testing Method for Oxygen Gas Permeability by Electrolytic Sensor Method). As the oxygen gas permeability measuring device, for example, an OXTRAN2 / 22 manufactured by MOCON Corporation, USA, can be used. For the measurement, the non-water-permeable gas-venting film is placed in the device so that the surface thereof is in contact with oxygen gas, and a permeation area of ​​50 cm is measured. 2 The measurement is performed under the following conditions. The measurement is performed according to the following procedure. First, a carrier gas is supplied into the device at a flow rate of 10 cc / min for at least 60 minutes to purge the device. Nitrogen gas containing approximately 5% hydrogen can be used as the carrier gas. After purging, a test gas is flowed into the device, and after allowing 12 hours for the gas to reach equilibrium, measurement is started under the above temperature and humidity conditions. The test gas used is dry oxygen containing at least 99.5% (volume) oxygen. At least three samples are measured under one condition, and the average of these measurements is used as the oxygen permeability value for that condition. For example, polyolefin resins have low water vapor permeability and high carbon dioxide permeability, making them suitable as resins for constituting the non-water-permeable gas-venting film of this modified example.

[0123] <5-2> In the first embodiment, a hole may be formed at any position in the exterior film 50, and the check valve 90 may be disposed in the hole. This can be similarly applied to the power storage device 200 of the second embodiment, the power storage device 300 of the third embodiment, and the power storage device 400 of the fourth embodiment.

[0124] <5-3> In the first embodiment, the configuration of the power storage device 10 can be modified as desired. The power storage device 10 may include at least one of the opening valve 491 and the opening valve 492 included in the power storage device 400 of the fourth embodiment. This modification can also be applied to the power storage device 200 of the second embodiment and the power storage device 300 of the third embodiment.

[0125] <5-4> In the first embodiment, the configuration of the lid body 60 can be modified as desired. FIG. 12 is a cross-sectional view of a power storage device 10 according to a modified example of the first embodiment. As shown in FIG. 12, the lid body 60 may include a lid main body 60A and a covering body 60B. In this modified example, for example, the lid main body 60A is preferably configured to include a conductive material. The covering body 60B covers a portion of the lid main body 60A. The covering body 60B is preferably configured to include a resin material. In this modified example, the sealing surface 63 of the lid body 60 is formed on the covering body 60B. To prevent a gap from forming between the exterior film 50 and the lid body 60, the covering body 60B preferably has a protrusion 68 that protrudes from the sealing surface 63. Note that the protrusion 68 may be omitted. The protrusion 68 may be formed integrally with the portion of the covering body 60B that forms the sealing surface 63, or may be formed separately from the portion of the covering body 60B that forms the sealing surface 63 and joined to the portion of the covering body 60B that forms the sealing surface 63. The protrusion 68 is preferably formed on the sealing surface 63 at a location where the root 70X of the first sealing portion 70 is located. In the example shown in Fig. 12, the root 70X of the first sealing portion 70 is located at the boundary 64 of the lid body 60. For this reason, the protrusion 68 is preferably formed at the boundary 64 on the sealing surface 63. The first sealing portion 70 is sealed with the protrusion 68 sandwiched between them. This modification can also be applied to the power storage device 200 of the second embodiment, the power storage device 300 of the third embodiment, and the power storage device 400 of the fourth embodiment.

[0126] <5-5> In the second embodiment, the location of the check valve 90 can be changed as desired. Fig. 13 is a front view of an electric storage device 200X according to a modified example of the second embodiment. Fig. 14 is a front view of the lid 60 of Fig. 13.

[0127] As shown in Fig. 13 , in an electricity storage device 200X, a check valve 90 may be disposed in the second sealing portion 80. At least a portion of the check valve 90 is sandwiched between the heat-sealable resin layer 53 of the exterior film 50 and the sealing surface 63 of the lid body 60. From the viewpoint of improving the sealing performance of the second sealing portion 80, as shown in Fig. 13 , it is preferable that a recess 69 be formed in the sealing surface 63 of the lid body 60, in which any portion of the check valve 90 facing the sealing surface 63 is disposed. In this modification, the check valve 90 may be a non-water-permeable gas-venting film. An opening valve 492 may be disposed in the recess 69.

[0128] When the check valve 90 is disposed in the second sealing portion 80, the check valve 90 may be disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 and the second sealing portion 80 corresponding to the other lid body 60. In this case, the valve opening pressure of the check valve 90 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 is preferably lower than the valve opening pressure of the check valve 90 disposed in the second sealing portion 80 corresponding to the other lid body 60. Gas generated inside the exterior body 40 is discharged from the check valve 90 disposed in the second sealing portion 80 corresponding to one of the lid bodies 60 before the check valve 90 disposed in the second sealing portion 80 corresponding to the other lid body 60. This allows the location from which gas is discharged to be limited.

[0129] In another example, in the power storage device 200, the check valve 90 may be disposed only in the second sealing portion 80 that corresponds to one of the lid bodies 60 of the second sealing portion 80. In other words, the check valve 90 is not disposed in the second sealing portion 80 that corresponds to the other lid body 60. In this case, the location from which the gas is discharged can be limited.

[0130] <5-6> In the second embodiment, the configuration of the lid 60 can be changed as desired. Fig. 15 is a front view of an electricity storage device 200Y according to another modification of the second embodiment. Fig. 16 is a front view of the lid 260 of Fig. 15.

[0131] As shown in Fig. 15 , the power storage device 200Y includes a lid 260. The power storage device 200Y may include at least one of a check valve 90 and an opening valve 492. The lid 260 is configured from a plurality of divided parts. In the example shown in Fig. 15 , the lid 260 includes a first part 261 and a second part 262. The lid 260 may be divided into three or more parts.

[0132] The first part 261 and the second part 262 preferably have recesses 261A, 262A formed therein in which the electrode terminal 30 is disposed. When the power storage device 200Y includes a check valve 90, the check valve 90 is sandwiched between the first part 261 and the second part 262. The first part 261 and the second part 262 preferably have recesses 261B, 262B formed therein in which any portion of the check valve 90 that faces the first part 261 and the second part 262 is disposed.

[0133] When the power storage device 200Y includes the open valve 492, the open valve 492 may be attached between the first part 261 and the second part 262 of the lid body 260. The open valve 492 may be attached to one lid body 260 and the other lid body 260. In this case, the opening pressure of the open valve 492 attached to one lid body 260 is preferably lower than the opening pressure of the open valve 492 attached to the other lid body 260. Gas generated inside the exterior body 40 is discharged from the open valve 492 attached to one lid body 260 before the open valve 492 attached to the other lid body 260. This allows the location from which the gas is discharged to be limited. Furthermore, even if gas continues to be generated inside the exterior body 40 after the open valve 492 attached to one lid body 260 is peeled off, the gas can be discharged by peeling off the open valve 492 attached to the other lid body 260.

[0134] In another example, in the power storage device 200Y, the open valve 492 may be attached to only one of the lid bodies 260 and the other lid body 260. In other words, the open valve 492 is not attached to the other lid body 260. In this case, the location from which gas is discharged can be limited. Note that the open valve 492 may be attached between the lid main body 60A and the cover body 60B, as shown in FIG. 12 .

[0135] <5-7> In the third embodiment, a check valve 90 may be arranged in at least one of the second sealing portion 80 and the lid body 60. In this modification, the check valve 90 arranged in the first sealing portion 70 may be omitted. In the third embodiment, opening valves 491, 492 may be arranged in at least one of the first sealing portion 70 and the second sealing portion 80.

[0136] <5-8> In the fourth embodiment, the location where the open valve 492 is disposed can be changed as desired. For example, as shown in FIG. 17 , when the electrode terminal 30 is disposed between the exterior film 50 and the sealing surface 63 of the lid 60, the open valve 492 may be disposed between the electrode terminal 30 and the exterior film 50. The open valve 492 is joined to the electrode terminal 30 and the exterior film 50. When the internal pressure of the exterior body 40 increases, the open valve 492 peels off from at least one of the heat-sealable resin layer 53 of the exterior film 50 and the electrode terminal 30, thereby forming an opening in the second sealing portion 80. Gas generated inside the exterior body 40 passes through the opening formed in the second sealing portion 80 and is discharged to the outside.

[0137] <5-9> In the fourth embodiment, the check valve 90 may be disposed in at least one of the first sealing portion 70, the second sealing portion 80, and the lid body 60. When the electricity storage device 400 includes the check valve 90 and at least one of the opening valves 491 and 492, the valve opening pressure of the check valve 90 is preferably lower than the valve opening pressures of the opening valves 491 and 492. In this modification, when the increase in internal pressure of the exterior body 40 is within an expected normal range, gas can be discharged by the check valve 90, and when the increase in internal pressure of the exterior body 40 is within an abnormal range, gas can be discharged by the opening valves 491 and 492.

[0138] <5-10> In the fourth embodiment, the configuration of the first sealed portion 70 can be modified as desired as long as it is closed by the exterior film 50. As shown in FIG. 18 , the first sealed portion 70 may be a portion where the first edge 50A and the second edge 50B of the exterior film 50 are butted together and the inner surfaces are joined together. The inner surfaces of the exterior film 50 may be joined together using, for example, front and back tape or adhesive. In this modification, the first sealed portion 70 is preferably folded toward the first surface 41. This modification can be similarly applied to the first to third embodiments.

[0139] <5-11> In the first embodiment, the exterior film 50 of the power storage device 10 may protrude outward in the FB direction beyond at least one of the two lid bodies 60. The electrode body 20 is sealed by closing the portion of the exterior film 50 that protrudes outward beyond the lid body 60. The portion of the exterior film 50 that protrudes beyond the lid body 60 may be folded like a Goebel-top pouch or a brick pouch. In this modification, the length of the electrode terminal in the FB direction is preferably such that it is exposed from the portion of the exterior film 50 that protrudes outward beyond the lid body 60. This modification can be similarly applied to the second to fourth embodiments.

[0140] <5-12> In the first embodiment, the exterior body 40 may not have one of the two lid bodies 60. In this modification, in the FB direction, in the portion of the exterior body 40 where the lid body 60 is omitted, the electrode body 20 is sealed by closing the portion of the exterior film 50 that protrudes outward beyond the electrode body 20. The portion of the exterior film 50 that protrudes outward beyond the electrode body 20 may be folded like a Goebel-top pouch or a brick-type pouch. This modification can be similarly applied to the second to fourth embodiments.

[0141] <5-13> In the first embodiment, the outer shape of the exterior body 40 can be changed as desired. The outer shape of the exterior body 40 may be a cylinder, a prism, or a cube. This modification can also be applied to the second to fourth embodiments.

[0142] 10, 200, 200X, 200Y, 300, 400: Electricity storage device 20: Electrode body 40: Exterior body 40A: Opening 50: Exterior film 53: Heat-sealable resin layer (innermost layer) 56: Heat-sealable resin layer (outermost layer) 60: Lid body 69: Recess 70, 370: First sealing portion 90: Check valve 60Z: 260Z, 460Z: Lid unit 491, 492: Opening valve

Claims

1. An electrode body; An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode assembly together with the exterior film; a second sealing portion in which the lid body and the exterior film are joined together, The power storage device is At least one of a check valve and an opening valve is disposed in the second sealing portion, The cover has a recess formed on a side surface thereof, At least one of the check valve and the opening valve is disposed in the recess. Energy storage device.

2. An electrode body, An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode assembly together with the exterior film; a second sealing portion in which the lid body and the exterior film are joined together, The power storage device is a check valve disposed in the second sealing portion; The exterior body includes at least two of the lid bodies, The opening pressure of the check valve arranged in the second sealing portion corresponding to one of the lids is lower than the opening pressure of the check valve arranged in the second sealing portion corresponding to the other lid. Energy storage device.

3. An electrode body, An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode assembly together with the exterior film; a second sealing portion in which the lid body and the exterior film are joined together, The power storage device is An opening valve is provided at the second sealing portion, The exterior body includes at least two of the lid bodies, The opening pressure of the opening valve arranged in the second sealing portion corresponding to one of the lid bodies is lower than the opening pressure of the opening valve arranged in the second sealing portion corresponding to the other lid body. Energy storage device.

4. The exterior body includes at least two of the lid bodies, At least one of the check valve and the opening valve is disposed in the second sealing portion corresponding to one of the lid bodies, The second sealing portion corresponding to the other lid body is not provided with the check valve and the opening valve. The power storage device according to claim 1 .

5. An electrode body; An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode body together with the exterior film, The power storage device is A check valve is provided which is attached to the lid, The exterior body includes at least two of the lid bodies, The opening pressure of the check valve attached to one of the lids is lower than the opening pressure of the check valve attached to the other lid. Energy storage device.

6. An electrode body; An electric storage device comprising: an exterior body that seals the electrode body, The exterior body is An exterior film that wraps the electrode body; a lid that seals the electrode body together with the exterior film, The power storage device is An opening valve is attached to the lid body, The lid body includes a plurality of elements, The opening valve is sandwiched between the elements. Energy storage device.

7. The exterior body includes at least two of the lid bodies, The opening pressure of the opening valve attached to one of the lids is lower than the opening pressure of the opening valve attached to the other lid. The electricity storage device according to claim 6 .

8. The exterior body includes at least two of the lid bodies, The opening valve is attached to one of the lids, The other lid body is not provided with the opening valve. The electricity storage device according to claim 6 .

9. A lid body used as an exterior body that seals the electrode body; At least one of a check valve and an opening valve attached to the lid body, A recess is formed on the side surface of the lid body in which at least one of the check valve and the opening valve is disposed. Lid unit.