Lid, electricity storage device, lid unit, electrode terminal unit, and method for manufacturing electricity storage device

Abstract

The lid body is used as an exterior body for an electricity storage device. The lid body includes a lid main body, a through hole penetrating the lid main body, an insulating member including an in-hole portion disposed in the through hole and an out-hole portion connected to the in-hole portion and disposed outside the through hole, and a barrier member covering at least a portion of the out-hole portion of the insulating member. The barrier member has at least one of a moisture barrier property and a gas barrier property higher than that of the insulating member.

Description

[Technical Field]

[0001] The present invention relates to a lid, an electricity storage device, a lid unit, an electrode terminal unit, and a method for manufacturing an electricity storage device. [Background technology]

[0002] Patent Document 1 discloses an example of an electricity storage device. This electricity storage device includes an electrode assembly, an electrode terminal connected to the electrode assembly, and an exterior body that seals the electrode assembly. The exterior body has an exterior film that wraps the electrode assembly and a lid that is joined to the exterior film. The lid has a through-hole into which the electrode terminal is inserted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-123686 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described electricity storage device, at least one of moisture and gas may enter the inside of the electricity storage device through a gap between the lid and the electrode terminal, and if at least one of moisture and gas comes into contact with the electrode body, the electrode body may deteriorate.

[0005] The present invention aims to provide a lid, an electricity storage device, a lid unit, an electrode terminal unit, and a method for manufacturing an electricity storage device that can prevent at least one of moisture and gas from entering the interior of the electricity storage device. [Means for solving the problem]

[0006] The lid body according to a first aspect of the present invention is a lid body used for an exterior body of an electricity storage device, and comprises a lid body, a through hole penetrating the lid body, an insulating member including an in-hole portion disposed in the through hole, and an out-hole portion connected to the in-hole portion and disposed outside the through hole, and a barrier member covering at least a portion of the out-hole portion of the insulating member, wherein the barrier member has at least one of moisture barrier properties and gas barrier properties higher than those of the insulating member.

[0007] A lid body according to a second aspect of the present invention is the lid body according to the first aspect, wherein the barrier member is formed integrally with the lid body.

[0008] A lid according to a third aspect of the present invention is the lid according to the first aspect, wherein the barrier member is configured as a separate member from the lid main body.

[0009] A lid according to a fourth aspect of the present invention is the lid according to any one of the first to third aspects, wherein the barrier member covers at least the end of the outside-hole portion on the through-hole side.

[0010] A lid body according to a fifth aspect of the present invention is a lid body according to any one of the first to fourth aspects, wherein the lid body is made of a conductive material, the barrier member has an end opposite the through hole in a portion that covers at least a portion of the outer-hole portion inside the energy storage device, and the end of the barrier member is insulated.

[0011] A lid unit according to a sixth aspect of the present invention is a lid unit used in the exterior of an electricity storage device, and includes a lid and a barrier member, wherein the lid has a lid main body having a through hole formed therein, and the barrier member is configured to cover at least a portion of the portion of the insulating member exposed from the through hole when an insulating member is attached to the lid so as to be exposed from the through hole, and has at least one of moisture barrier properties and gas barrier properties that are higher than those of the insulating member.

[0012] A seventh 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 has an exterior film that wraps the electrode body and a lid body that seals the electrode body together with the exterior film, and the lid body comprises a lid main body having a first surface and a second surface opposite to the first surface, a through hole that penetrates the first surface and the second surface, an insulating member that includes an in-hole portion that is disposed in the through hole and an out-hole portion that is connected to the in-hole portion and is disposed outside the through hole, and a barrier member that covers at least a portion of the out-hole portion of the insulating member, and the barrier member has at least one of moisture barrier properties and gas barrier properties that are higher than those of the insulating member.

[0013] A lid body according to an eighth aspect of the present invention is a lid body used as an exterior body for an electricity storage device, and comprises a lid main body containing a conductive material, a through hole penetrating the lid main body, and an insulating member disposed in the through hole, and the thickness of the lid main body is 1.0 mm or more.

[0014] An electrode terminal unit according to a ninth aspect of the present invention is an electrode terminal unit attached to a lid used in an exterior body of an electricity storage device, and comprises a terminal body, an insulating member joined to the terminal body, and a barrier member covering at least a portion of the insulating member, wherein the barrier member has at least one of moisture barrier properties and gas barrier properties higher than those of the insulating member.

[0015] A tenth aspect of the present invention provides a method for manufacturing an electricity storage device, the method comprising: an electrode assembly; and an exterior body sealing the electrode assembly; the exterior body having an exterior film wrapping the electrode assembly; and a lid body sealing the electrode assembly together with the exterior film; the lid body comprising a lid body, a through hole penetrating the lid body, an insulating member including an in-hole portion disposed in the through hole and an out-hole portion connected to the in-hole portion and disposed outside the through hole; and a barrier member covering at least a portion of the out-hole portion of the insulating member, the barrier member having at least one of a moisture barrier property and a gas barrier property higher than that of the insulating member. The method for manufacturing an electricity storage device includes a step of placing the lid body on the electrode assembly.

[0016] A manufacturing method for an electricity storage device according to an eleventh aspect of the present invention is a manufacturing method for an electricity storage device comprising: an electrode assembly; and an exterior body sealing the electrode assembly, the exterior body having an exterior film wrapping the electrode assembly; and a lid body sealing the electrode assembly together with the exterior film, the lid body comprising a lid main body containing a conductive material, a through hole penetrating the lid main body, and an insulating member disposed in the through hole, the lid main body having a thickness of 1.0 mm or more. The manufacturing method for the electricity storage device includes a step of arranging the lid body on the electrode assembly. [Effects of the Invention]

[0017] The lid, electricity storage device, lid unit, electrode terminal unit, and method for manufacturing an electricity storage device according to the present invention can prevent at least one of moisture and gas from entering the interior of the electricity storage device. [Brief explanation of the drawings]

[0018] [Figure 1A] FIG. 1 is a perspective view of an electricity storage device according to an embodiment. [Figure 1B] 1B is a diagram showing a method for measuring the seal strength of the second sealing portion of the electricity storage device in FIG. 1A. FIG. [Figure 2] 1B is a cross-sectional view showing the layer structure of an exterior film included in the electricity storage device of FIG. 1A. [Figure 3] FIG. 1B is a diagram showing the state in which the exterior film provided on the electricity storage device of FIG. 1A is unfolded. [Figure 4] 1B is a perspective view of the front side of a lid provided in the electricity storage device of FIG. 1A. FIG. [Figure 5] 1B is a perspective view of the rear side of a lid provided in the electricity storage device of FIG. 1A. FIG. [Figure 6] FIG. 1B is a cross-sectional view taken along line D6-D6 in FIG. 1A. [Figure 7] 1B is a cross-sectional view taken along line D7-D7 in FIG. 1A. [Figure 8] 1B is a flowchart showing an example of a method for manufacturing the electricity storage device of FIG. 1A. [Figure 9] FIG. 10 is a cross-sectional view of a cover according to a first modified example. [Figure 10] FIG. 10 is a cross-sectional view of a lid according to a second modified example. [Figure 11] FIG. 10 is a cross-sectional view of a cover according to a third modified example. [Figure 12] FIG. 10 is a cross-sectional view of a cover according to a fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an electricity storage device according to an 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.

[0020] [Embodiment] <1-1. Configuration of the power storage device> FIG. 1A is a perspective view schematically illustrating an electricity storage device 10 according to an embodiment. FIG. 1B is a diagram illustrating a method for measuring the seal strength of a second sealed portion 100B of the electricity storage device 10 of FIG. 1A. FIG. 2 is a cross-sectional view illustrating the layer structure of an exterior film 50 included in the electricity storage device 10 of FIG. 1A. FIG. 3 is a diagram 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 the rear side of a lid body 60 included in the electricity storage device 10 of FIG. 1A. FIG. 5 is a perspective view of the front side of the lid body 60 of FIG. 4. FIG. 6 is a cross-sectional view taken along line D6-D6 in FIG. 1A. FIG. 7 is a cross-sectional view taken along line D7-D7 in 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, LR, and FB are common to all subsequent figures.

[0021] The electricity storage device 10 includes an electrode assembly 20, an electrode terminal unit 30, and an exterior body 40. The electrode assembly 20 includes electrodes (positive and negative electrodes) constituting an electricity 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 electrode assembly 20 has a substantially rectangular parallelepiped shape. Note that the term "substantially rectangular parallelepiped" 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 electrode assembly 20 may have a cylindrical or polygonal prism shape, for example.

[0022] In this embodiment, the electricity storage device 10 includes two electrode terminal units 30. The electrode terminal unit 30 includes a terminal body 31, an insulating member 32, and a barrier member 33. The terminal body 31 is a metal terminal used for inputting and outputting electric power to and from the electrode assembly 20. The shape of the terminal body 31 can be selected arbitrarily. In the example shown in FIG. 1A etc., the shape of the terminal body 31 is cylindrical. The shape of the terminal body 31 may also be a rectangular pillar or a plate. One end of the terminal body 31 is electrically connected to an electrode (positive electrode or negative electrode) included in the electrode assembly 20. The other end of the terminal body 31 protrudes outward from, for example, an edge of the exterior body 40. Note that the terminal body 31 only needs to be capable of inputting and outputting electric power to and from the electrode assembly 20, and does not have to protrude from, for example, the exterior body 40. For example, if the lid body 60 described later is made of a conductive material, the lid body 60 may also function as the terminal body 31. In this case, the lid body 60, which functions as the terminal body, may or may not protrude from the outer casing 40.

[0023] The metal material constituting the terminal body 31 is, for example, aluminum, nickel, or copper. For example, when the electrode body 20 is a lithium-ion battery, the terminal body 31 connected to the positive electrode is usually made of aluminum, and the terminal body 31 connected to the negative electrode is usually made of copper, nickel, or the like. 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. The insulating member 32 covers a portion of the surface of the terminal body 31. The barrier member 33 covers at least a portion of the insulating member 32. Details of the insulating member 32 and the barrier member 33 will be described later.

[0024] The exterior body 40 seals the electrode assembly 20. The exterior body 40 has an exterior film 50 and a lid 60. The exterior film 50 wraps the electrode assembly 20. In this embodiment, the exterior film 50 is wrapped around the electrode assembly 20. The lid 60 is disposed on the side of the electrode assembly 20 in the FB direction. In another example, the electrode assembly 20 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings are formed at both ends in the FB direction, and the openings may be closed by the lid 60. In yet another example, the electrode assembly 20 connected to the lid 60 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings are formed, and the openings may be closed by the lid 60.

[0025] For example, there is a method of forming a storage portion (recess) in the exterior film 50 through cold forming to store the electrode assembly 20. However, it is not necessarily easy to form a deep storage portion using this method. Attempting to form a deep storage portion (recess) through 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 maximize 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.

[0026] As shown in FIG. 2 , the exterior film 50 is a laminate (laminate film) having, for example, 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; for example, it may not include the barrier layer 52. That is, the exterior film 50 may be made of any flexible and easily bendable material, such as a resin film. Note that the exterior film 50 is preferably heat-sealable. The innermost and outermost layers of the exterior film 50 may be heat-sealable resin layers 53. In this case, the exterior film 50 may encase the electrode assembly 20 and the lid 60 by joining the outermost and innermost layers.

[0027] The exterior film 50 may be composed of a laminate including at least a barrier layer 52 and a heat-sealable resin layer 53 in this order. In this laminate, the base layer 51 is an optional layer, and the side of the barrier layer 52 opposite to the heat-sealable resin layer 53 is the outermost layer, and the heat-sealable resin layer 53 is the innermost layer.

[0028] The overall thickness of the exterior film 50 can be selected arbitrarily. From the viewpoint of strength, the thickness of the exterior film 50 is preferably 50 μm or more. From the viewpoint of formability or conformability, the thickness of the exterior film 50 is preferably 1200 μm or less. The thickness of the exterior film 50 is preferably within the range of 50 μm or more and 1200 μm or less.

[0029] The substrate layer 51 included in the exterior film 50 is a layer that imparts heat resistance to the exterior film 50 and prevents pinholes from forming 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 prevented. 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. The thickness of the base layer 51 is preferably, for example, 5 to 300 μm, and more preferably 5 to 150 μm, from the viewpoint of film strength.

[0030] The barrier layer 52 is a layer that prevents at least moisture from penetrating. The barrier layer 52 is bonded to the base 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. Other examples of the barrier layer 52 include resin films 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.

[0031] In the barrier layer 52, the layer made of the aforementioned metallic material may contain recycled metallic material. Examples of recycled metallic 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 solely of recycled material, or may be made of a mixture of recycled and virgin material. Note that recycled metallic material refers to metallic material that has been made reusable by collecting, isolating, and refining various products used in the market or waste from manufacturing processes. Furthermore, virgin metallic material refers to new metallic material refined from natural metallic resources (raw materials) and is not recycled material.

[0032] 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 the formability or conformability, 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 in JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14. From the viewpoint of improving the mechanical strength of the packaging film 50, the aluminum alloy foil is preferably an aluminum alloy foil containing magnesium. In the aluminum alloy foil containing magnesium (100% by mass), the magnesium content is preferably 0.2 to 5.6% by mass, and more preferably 0.2 to 3.0% by mass.Examples of aluminum alloy foils containing magnesium include aluminum alloy foils having compositions defined in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JISH4000:2017 A5052P-O. The aluminum alloy foil is also preferably an aluminum alloy foil containing manganese. In the aluminum alloy foil containing manganese (100% by mass), the manganese content is preferably 0.3 to 1.5% by mass, and more preferably 1.0 to 1.5% by mass. Examples of aluminum alloy foils containing manganese include aluminum alloy foils having compositions defined in JIS H4000:2017 A3003P-O, JIS H4000:2017 A3103P-O, JISH4000:2017 A3004P-O, and JISH4000:2017 A3104P-O.

[0033] Examples of 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.

[0034] Specific examples of austenitic stainless steels that can be used to form the stainless steel foil include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred.

[0035] 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, about 5 to 1000 μm. The thickness of the barrier layer 52 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 52 is preferably about 9.0 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. Preferred ranges for the thickness of the barrier layer 52 include about 9.0 to 1000 μm, about 9.0 to 1000 μm, about 9.0 to 1000 μm, about 9.0 to 1000 μm, about 9.0 to 85 μm, about 9.0 to 50 μm, about 9.0 to 40 μm, about 9.0 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 52 is made of an aluminum alloy foil, the above-mentioned ranges are particularly preferred. 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, while increasing the capacity of the electricity storage device increases the weight of the electricity storage device, 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.

[0036] 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 using 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 using 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.

[0037] The corrosion-resistant coating prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the base layer 51 during molding of the exterior film 50, 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 base layer 51 and the barrier layer 52 during heat sealing and between the base layer 51 and the barrier layer 52 during molding.

[0038] 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 viewpoints of sealability and strength, the thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 1000 μm, and more preferably 40 to 150 μm.

[0039] The exterior film 50 preferably has one or more layers with 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.

[0040] 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, and most preferably in the range of 1000 μm to 3000 μm.

[0041] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 0.5 mm, more preferably 1.0 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5.0 mm, and even more preferably 2.0 mm. When the buffer layer is made of rubber, the preferred ranges of the buffer layer thickness are 1.0 mm to 2.0 mm, 1.0 mm to 5.0 mm, 1.0 mm to 10 mm, 0.5 mm to 2.0 mm, 0.5 mm to 5.0 mm, and 0.5 mm to 10 mm.

[0042] 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 the manufacture of the energy storage device 10.

[0043] The lid 60 has a lid main body 70 and a covering body 90 that covers a part of the lid main body 70. The lid 60 can be manufactured, for example, by injection molding the covering body 90 onto the lid main body 70.

[0044] In this embodiment, the lid body 70 is made up of a conductive material. "Made up of a conductive material" means that when the entire material making up the lid body 70 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 making up the lid body 70 can contain, in addition to the conductive material, a material other than the conductive material. The lid body 70 made up of a conductive material preferably has the corrosion-resistant coating described for the barrier layer 52.

[0045] The conductive material constituting the lid body 70 is, for example, a metal material. The metal material constituting the lid body 70 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 70 connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The lid body 70 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the lid body 70 connected to the negative electrode may be nickel-plated copper. The material constituting the lid body 70 may include recycled metal material. The lid body 70 has a base 71 and a wall 72.

[0046] The base 71 shown in FIGS. 4 and 5 is, for example, a rectangular plate and has a first surface 71A and a second surface 71B. The first surface 71A faces the outside. The second surface 71B is the surface opposite to the first surface 71A. The second surface 71B faces the electrode assembly 20. The lid 60 may be disposed so that the first surface 71A faces the electrode assembly 20, in other words, so that the second surface 71B faces the outside. The base 71 may have any shape, such as a cylinder, a prism, a rectangular parallelepiped, or a cube. A through hole 71Z into which the electrode terminal unit 30 is inserted is formed in the base 71. The position at which the through hole 71Z is formed in the base 71 can be selected arbitrarily. In the example shown in FIG. 4 and other figures, the through hole 71Z is formed approximately in the center of the base 71. When the base 71 is made of a conductive material, the end of the current collector of the electrode body 20 may be connected to the second surface 71B of the base 71. When the end of the current collector of the electrode body 20 is connected to the second surface 71B of the base 71, the electrode terminal unit 30 may be omitted. When the electrode terminal unit 30 is omitted, the through-hole 71Z can be used, for example, in the manufacturing process of the electricity storage device 10, as a hole for injecting an electrolyte solution or a hole for inserting a thermocouple for measuring the temperature of the electrode body 20. When the through-hole 71Z is used as a hole for injecting an electrolyte solution or a hole for inserting a thermocouple for measuring the temperature of the electrode body 20, it is preferable that the through-hole 71Z is closed with any member when the electricity storage device 10 is in use.

[0047] The wall portion 72 is covered by a cover 90. The wall portion 72 is frame-shaped and rises from the edge of the base portion 71. The wall portion 72 has a first wall portion 72A, a second wall portion 72B, a third wall portion 72C, and a fourth wall portion 72D. The first wall portion 72A forms the upper surface of the lid main body 70. The first wall portion 72A extends in a first direction (in this embodiment, the LR direction) when the lid main body 70 is viewed from the front. The second wall portion 72B and the third wall portion 72C are connected to the first wall portion 72A and the fourth wall portion 72D and form the side surfaces of the lid main body 70. The second wall portion 72B and the third wall portion 72C extend in a second direction (in this embodiment, the UD direction) that intersects with the first direction when the lid main body 70 is viewed from the front. In this embodiment, the first direction and the second direction are perpendicular to each other when the lid main body 70 is viewed from the front. The first direction and the second direction do not have to be perpendicular to each other in a front view of the lid body 70. The fourth wall portion 72D forms the lower surface of the lid body 70. The fourth wall portion 72D extends in the first direction (the LR direction in this embodiment) in a front view of the lid body 70.

[0048] At least a portion of the surface 72X of the wall portion 72 is covered with the covering 90. In this embodiment, the entire surface 72X of the wall portion 72 is covered with the covering 90.

[0049] The covering 90 shown in Figures 4, 5, 6, etc. is made of a resin material. Here, "made of a resin material" means that, when the entire material constituting the covering 90 is taken as 100% by mass, the resin material content 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 covering 90 can contain materials other than the resin material in addition to the resin material.

[0050] Specific examples of resins 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 copolymer. Among these, heat-sealable resins such as polyester and polyolefin are preferred, with polyolefin being more preferred. When the resin material is a resin, the covering 90 may be molded using any molding method.

[0051] The resin material contained in the material constituting the coating 90 is preferably an olefin-based random copolymer, more preferably a resin containing a polyolefin skeleton as the main component, even more preferably a polyolefin as the main component, and even more preferably a polypropylene as the main component. The polyolefin may be an acid-modified polyolefin. The resin material contained in the material constituting the coating 90 preferably contains multiple types of amide-based lubricants. Furthermore, the resin material contained in the material constituting the coating 90 preferably contains, in addition to saturated fatty acid amides, multiple types of amide-based lubricants further containing unsaturated fatty acid amides. The resin material contained in the material constituting the coating 90 may be a polyolefin resin to which a propylene-based elastomer having a melting point higher than 150°C has been added. Note that the term "main component" refers to a material that accounts for, for example, 35% by mass or more, 50% by mass or more, 90% by mass or more, or 95% by mass or more of the materials contained in the constituent elements.

[0052] 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 / decane dicarboxylate). Among these, polybutylene terephthalate is preferred as the resin material from the viewpoint of improving heat resistance and pressure resistance.

[0053] 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, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (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.

[0054] The resin as the resin material may contain a filler as needed. Specific examples of fillers 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 covering 90 to temperature changes can be improved.

[0055] The melt mass flow rate of the resin material contained in the material constituting the coating 90 is preferably in the range of 1 g / 10 min to 100 g / 10 min, and more preferably in the range of 5 g / 10 min to 80 g / 10 min. The melt mass flow rate is measured in accordance with JIS K7210-1:2014. The temperature for measuring the melt mass flow rate is 230°C.

[0056] The covering body 90 has a lid seal portion 91. The lid seal portion 91 is heat-sealed to the heat-fusible resin layer 53 of the exterior film 50. The lid seal portion 91 includes a first seal surface 91A, a second seal surface 91B, a third seal surface 91C, and a fourth seal surface 91D. The first seal surface 91A forms the upper surface of the lid body 60. The first seal surface 91A is formed on the first wall portion 72A. The first seal surface 91A extends in a first direction (the LR direction in this embodiment) when the lid body 60 is viewed from the front. The second seal surface 91B and the third seal surface 91C are connected to the first seal surface 91A and the fourth seal surface 91D and form the side surfaces of the lid body 60. The second seal surface 91B is formed on the second wall portion 72B. The third seal surface 91C is formed on the third wall portion 72C. The second seal surface 91B and the third seal surface 91C extend in a second direction (UD direction in this embodiment) that intersects with the first direction in a front view of the lid 60. In this embodiment, the first direction and the second direction are perpendicular to each other in a front view of the lid 60. The first direction and the second direction do not have to be perpendicular to each other in a front view of the lid 60. The fourth seal surface 91D forms the lower surface of the lid 60. The fourth seal surface 91D extends in the first direction (LR direction in this embodiment) in a front view of the lid 60. The fourth seal surface 91D is formed on the fourth wall portion 72D.

[0057] The lid seal portion 91 further includes boundaries 92, 93, 94, and 95. The boundary 92 is the boundary between the first seal surface 91A and the second seal surface 91B. The boundary 93 is the boundary between the first seal surface 91A and the third seal surface 91C. The boundary 94 is the boundary between the fourth seal surface 91D and the second seal surface 91B. The boundary 95 is the boundary between the fourth seal surface 91D and the third seal surface 91C. The boundaries 92 to 95 may have angular shapes or may be rounded by applying a rounding process. In this embodiment, the boundaries 92 to 95 are angular. If the boundaries 92 to 95 have rounded shapes, the radius of curvature of the boundaries 92 to 95 is preferably in the range of more than 0 mm and not more than 2.0 mm.

[0058] The lid 60 may be bonded to the exterior film 50 via an adhesive film instead of the covering 90. 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 selected appropriately depending on the materials constituting the heat-sealable resin layer 53 of the exterior film 50 and the material 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 .

[0059] 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.

[0060] The adhesive film preferably has adhesiveness. When the second sealing portion 100B described below 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, adhesiveness 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 wt % or less.

[0061] When the lid body 60 is plate-shaped, it is preferable that the lid body 60 has 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 lid seal portion 91 of the lid body 60 has a certain width in the FB direction so that the lid seal portion 91 of the lid body 60 and the exterior film 50 can be appropriately heat-sealed when forming the second sealing portion 100B described below. The minimum width of the lid seal portion 91 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 width of the lid seal portion 91 of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 10 mm. The maximum width of the lid seal portion 91 of the lid body 60 may be 20 mm or more. The preferred width ranges for the lid seal portion 91 of 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 specified by the JIS (Japanese Industrial Standards) "Packaging Terminology" standard. The width of the lid seal portion 91 of the lid body 60 may vary depending on the location. When the width of the lid seal portion 91 of the lid body 60 varies depending on the location, the width of the lid seal portion 91 of the lid body 60 is the width of the widest part.

[0062] In this embodiment, with the exterior film 50 wrapped around the electrode body 20, the surfaces (heat-fusible resin layers 53) of the exterior film 50 facing each other are heat-sealed to form the first sealed portion 100A.

[0063] The first sealed portion 100A is formed by heat-sealing a portion of the exterior film 50 including the first edge 50A and a portion of the exterior film 50 including the second edge 50B shown in FIG. 3 . The first sealed portion 100A extends in the longitudinal direction of the exterior body 40. The position at which the first sealed portion 100A is formed in the exterior body 40 can be selected arbitrarily. In this embodiment, the base 70X of the first sealed portion 100A is preferably located on the side 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 100AX of the first sealed portion 100A may be located on any surface of the exterior body 40. In this embodiment, the first sealed portion 100A protrudes outward beyond the electrode assembly 20 in a plan view. The first sealed portion 100A may be folded, for example, toward the second surface 42 or the first surface 41 of the exterior body 40.

[0064] In this embodiment, the second sealing portion 100B is formed by heat-sealing the heat-fusible resin layer 53 of the exterior film 50 and the lid seal portion 91 of the lid body 60. Hereinafter, the seal strength between the heat-fusible resin layer 53 of the exterior film 50 and the lid seal portion 91 of the lid body 60 may be referred to as the seal strength (bonding strength) of the second sealing portion 100B. The seal strength of the second sealing portion 100B is the seal strength between the heat-fusible resin layer 53 and the lid body 60 at the long side portion of the lid seal portion 91, i.e., the lid seal portion 91 extending in the L-R (width) direction in FIG. 1A .

[0065] The seal strength of the second sealing portion 100B is measured as follows. First, a slit is made in the portion of the exterior film 50 that constitutes the first surface 41 of the exterior body 40, forming three strip-shaped members 41X, 41Y, and 41Z (see the two-dot chain lines in FIG. 1B) aligned in the L-R direction. The width of the three strip-shaped members 41X, 41Y, and 41Z in the L-R 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 100B. The length of the lid body 60 in the L-R direction is 45 mm or more. Next, the end of each of the strip-shaped members 41X, 41Y, and 41Z opposite the end joined to the lid body 60 is pulled upward in the UD direction (away from the first surface 41), thereby measuring the seal strength of each of the strip-shaped members 41X, 41Y, and 41Z. The distance between the zippers in the UD direction is 50 mm. The seal strength of the strip-shaped members 41X, 41Y, and 41Z is the peak value of each seal strength. In this embodiment, the seal strength of the second sealing portion 100B is the average value of the seal strengths of the strip-shaped members 41X, 41Y, and 41Z. When the length of the lid body 60 in the L-R direction is 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 using the same method as when the length of the lid body 60 in the L-R direction is 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 100B is the average value of the seal strengths of the three strip-shaped members converted to a 15 mm width. Note that when the lid body 60 is divided into multiple parts including long and short sides, the seal strength of the second sealing portion 100B is the seal strength of the long sides of the lid seal portions 91 of the multiple parts.

[0066] From the viewpoint of suitably maintaining the state in which the electrode assembly 20 is sealed by the exterior housing 40, the seal strength of the second sealing unit 100B 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 100B is 40 N / 15 mm or more, the state in which the electrode assembly 20 is sealed by the exterior housing 40 is suitably maintained even after the electricity storage device 10 has been used for, for example, several years (less than 10 years). When the seal strength of the second sealing unit 100B is 85 N / 15 mm or more, the state in which the electrode assembly 20 is sealed by the exterior housing 40 is suitably maintained even after the electricity storage device 10 has been used for, for example, 10 years or more. The seal strength of the second sealing unit 100B is preferably 300 N / 15 mm or less. The preferred range of the seal strength of the second sealing portion 100B 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.

[0067] In this embodiment, the lid body 60 preferably has a protrusion 96 protruding from the lid seal portion 91 so that a gap is less likely to form between the exterior film 50 and the lid body 60. The protrusion 96 may be formed integrally with the covering body 90, or may be formed separately from the covering body 90 and joined to the covering body 90. In this embodiment, the protrusion 96 is formed integrally with the covering body 90. The position at which the protrusion 96 is formed in the lid seal portion 91 can be selected arbitrarily. A gap between the exterior film 50 and the lid body 60 is likely to form, for example, between the base 100AX of the first sealing portion 100A and the lid body 60. In particular, when the base 100AX of the first sealing portion 100A is located between the boundary 92 and boundary 95 of the lid body 60, the resin filling ability between the base 100AX of the first sealing portion 100A and the lid body 60 is likely to decrease. For this reason, the protrusion 96 is preferably formed in the lid seal portion 91 at a location where the base 100AX of the first sealing portion 100A is located. In this embodiment, the base 100AX of the first sealing portion 100A is located at the boundary 92 of the lid body 60. For this reason, the protrusion 96 is preferably formed in the lid seal portion 91 at the boundary 92. In this embodiment, the first sealing portion 100A is sealed with the protrusion 96 sandwiched between them. Note that the protrusion 96 may be formed on at least one of the first seal surface 91A, the second seal surface 91B, the third seal surface 91C, the fourth seal surface 91D, the boundary 93, the boundary 94, and the boundary 95.

[0068] The shape of the protrusion 96 can be selected arbitrarily. In this embodiment, the shape of the protrusion 96 is plate-like. The thickness of the protrusion 96 can be selected arbitrarily. In this embodiment, the thickness of the protrusion 96 becomes thinner with increasing distance from the boundary 92. In other words, the protrusion 96 has a tapered shape with increasing distance from the boundary 92. The thickness of the protrusion 96 may be constant, or may increase with increasing distance from the boundary 92.

[0069] The direction in which the protrusion 96 extends can be selected arbitrarily. In this embodiment, the protrusion 96 extends along a first direction (in this embodiment, the LR direction). The protrusion 96 may extend along a second direction (in this embodiment, the UD direction). The protrusion 96 may extend in a third direction that intersects with the first direction (in this embodiment, the LR direction) and the second direction (in this embodiment, the UD direction) when the lid 60 is viewed from the front.

[0070] The length of the protrusion 96 can be selected arbitrarily within a range equal to or less than the length of the first sealing portion 100A. For example, the length of the protrusion 96 may be substantially equal to the length of the first sealing portion 100A, or may be 30% to 50% of the length of the first sealing portion 100A.

[0071] As described above, a through hole 71Z is formed in the base 71 of the cover 60 for inserting the electrode terminal unit 30, etc. An insulating member 32 is joined to at least a portion of the outer surface of the terminal body 31 that is inserted into the through hole 71Z so as to prevent electrical continuity between the base 71 and the terminal body 31. The insulating member 32 may be made of any insulating material. Examples of the insulating member 32 include resins such as polypropylene, polybutylene terephthalate, polyethylene terephthalate, polyphenylene sulfide, and polyether ether ketone. In this embodiment, the insulating member 32 is divided into a hole-mounted portion 32A, a first outside-hole mounted portion 32B, and a second outside-hole mounted portion 32C. The hole-mounted portion 32A is disposed within the through hole 71Z. The first outside-hole mounted portion 32B is connected to the hole-mounted portion 32A and disposed outside the through hole 71Z in the internal space of the exterior body 40. The second out-of-hole portion 32C is connected to the in-hole portion 32A and is disposed outside the through-hole 71Z outside the exterior body 40. The internal space of the exterior body 40 is defined by the second surfaces 71B of the pair of lid bodies 60 and the heat-sealable resin layer 53 of the exterior film 50. Note that the insulating member 32 does not necessarily have to have the first out-of-hole portion 32B or the second out-of-hole portion 32C.

[0072] When the electrode terminal unit 30 is composed only of the terminal body 31 and the insulating member 32, at least one of moisture and gas present outside the exterior body 40 may infiltrate into the internal space of the exterior body 40 via the second out-hole-arranged portion 32C and the in-hole-arranged portion 32A. In this embodiment, the electrode terminal unit 30 has a barrier member 33 to prevent at least one of moisture and gas from infiltrating into the internal space of the exterior body 40. Note that "preventing at least one of moisture and gas from infiltrating into the internal space of the exterior body 40" includes at least one of a first meaning and a second meaning. The first meaning is to restrict the infiltration of moisture and gas into the internal space of the exterior body 40. The second meaning is to delay the time from when the moisture and gas reach the in-hole-arranged portion 32A to when the moisture and gas are released into the internal space of the exterior body 40.

[0073] The material constituting the barrier member 33 can be selected arbitrarily as long as it has at least one of moisture barrier property and gas barrier property higher than that of the material constituting the insulating member 32. High moisture barrier property means low water vapor permeability. High gas barrier property means low permeability to gases such as carbon monoxide, oxygen, or carbon dioxide. In this embodiment, the barrier member 33 has higher moisture barrier property and gas barrier property than the insulating member 32. The material constituting the barrier member 33 is, for example, metal or ceramic. The barrier member 33 may be a film including the barrier layer 52 of the exterior film 50.

[0074] The barrier member 33 is arranged so as to cover at least a portion of the first out-of-hole portion 32B of the insulating member 32. The barrier member 33 is preferably joined to the first out-of-hole portion 32B by any method so as to cover at least a portion of the first out-of-hole portion 32B. From the viewpoint of preventing moisture and gas that have reached the in-hole portion 32A of the insulating member 32 from being immediately released into the internal space of the exterior body 40, the barrier member 33 preferably covers at least the end of the first out-of-hole portion 32B on the through-hole 71Z side.

[0075] The barrier member 33 is arranged so as to cover at least a portion of the second out-of-hole portion 32C of the insulating member 32. The barrier member 33 is preferably joined to the second out-of-hole portion 32C by any method so as to cover at least a portion of the second out-of-hole portion 32C. From the viewpoint of preventing moisture and gas from reaching the in-hole portion 32A of the insulating member 32 from the outside of the exterior body 40, the barrier member 33 preferably covers at least the end of the second out-of-hole portion 32C on the through-hole 71Z side. In this embodiment, the barrier member 33 is arranged so as to cover substantially the entire outer surface of the insulating member 32.

[0076] When the lid main body 70 is configured to include a conductive material, the end 33A of the barrier member 33 is preferably insulated. The end 33A is the end of the barrier member 33 opposite the through-hole 71Z in a portion that covers at least a part of the first out-of-hole portion 32B. In this embodiment, the end 33A is insulated by being covered with the insulating member 32. In another example, the end 33A may be insulated by being provided with an insulating coating, or may be insulated by being covered with an insulating member other than the insulating member 32.

[0077] In this embodiment, the insulating member 32 and the barrier member 33 are previously joined to the terminal body 31, but the insulating member 32 and the barrier member 33 may be joined to the lid body 60, and only the terminal body 31 may be inserted into the through-hole 71Z. In another example, the barrier member 33 may be joined to the lid body 60, and the terminal body 31 to which the insulating member 32 is joined may be inserted into the through-hole 71Z. The object in which the lid body 60 and the barrier member 33 are joined constitutes the lid unit 60Z.

[0078] <1-2. Method for manufacturing electricity storage devices> FIG. 8 is a flowchart showing an example of a method for manufacturing the electricity storage device 10. The method for manufacturing the electricity storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, and a fifth step. The first step to the fifth step are performed, for example, by a manufacturing apparatus for the electricity storage device 10. At least a part of the first step to the fifth step may be performed by an operator. Note that the first step to the fifth step are names of the steps in the method for manufacturing the electricity storage device 10 specified for convenience, and do not necessarily refer to the order of the steps. The order of the first step to the fifth step can be changed as desired as long as it is not technically inconsistent.

[0079] In the first process of step S11, the manufacturing device places a pair of lid bodies 60 on either side of the electrode body 20 in the FB direction.

[0080] The second process of step S12 is performed after the first process. In the second process, the manufacturing apparatus joins the electrode terminal unit 30 connected to the electrode assembly 20 to the lid body 60. Note that the lid body 60 with the electrode terminal unit 30 joined thereto may be disposed in the first process, and the electrode terminal unit 30 and the electrode assembly 20 may be connected in the second process.

[0081] The third step of step S13 is performed after the second step. In the third step, the manufacturing apparatus winds 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 with 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. Note that 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. The electrode body 20 with the electrode terminal unit 30 connected thereto may be housed inside an exterior film 50 configured in a cylindrical shape so that openings are formed at both ends in the FB direction, and after the electrode body 20 and the lid 60 are joined together, the opening may be closed by the lid 60. In yet another example, the electrode body 20 with the electrode terminal unit 30 connected to the lid 60 may be housed inside an exterior film 50 configured in a cylindrical shape so that openings are formed at both ends in the FB direction, and the opening may be closed by the lid 60.

[0082] The fourth step of step S14 is performed after the third step. In the fourth step, the manufacturing device heat-seals the exterior film 50 and the lid 60 together to form the second sealed portion 100B.

[0083] The fifth step of step S15 is performed before or after the fourth step. In the fifth step, the manufacturing apparatus forms a first sealing portion 100A by heat-sealing the heat-sealable resin layer 53 in a portion including the first edge 50A of the exterior film 50 and the heat-sealable resin layer 53 in a portion including the second edge 50B while restricting the movement of the electrode body 20 and the lid body 60 and applying tension to the exterior film 50.

[0084] <1-3. Actions and Effects of Electricity Storage Devices> In the energy storage device 10, at least a portion of the first outside-hole portion 32B and the second outside-hole portion 32C of the insulating member 32 is covered by the barrier member 33, thereby preventing at least one of moisture and gas from entering the internal space from the outside of the outer casing 40.

[0085] [2. Modifications] The above-described embodiments are examples of possible forms of the lid, electricity storage device, lid unit, electrode terminal unit, electricity storage device, and electricity storage device manufacturing method according to the present invention, and are not intended to limit the forms. The lid, electricity storage device, lid unit, electrode terminal unit, electricity storage device, and electricity storage device manufacturing method according to the present invention may take forms different from those exemplified in the embodiments. Examples include forms in which part of the configuration of the embodiments is replaced, modified, or omitted, or forms in which a new configuration is added to the embodiments. Some examples of modified embodiments are shown below. Note that the following modified forms can be combined with each other as long as there is no technical contradiction.

[0086] <2-1. First modified example> In the above embodiment, the barrier member 33 was separate from the lid body 70, but if the lid body 70 is configured to include a conductive material, the barrier member 33 may be configured integrally with the lid body 70. In other words, the barrier member 33 may be configured by deforming a portion of the lid body 70. In both cases where the barrier member 33 and the lid body 70 are separate, and where the barrier member 33 and the lid body 70 are integrally formed, the presence or absence of the barrier member 33 can be confirmed by observing the surface of the boundary between the barrier member 33 and the lid body 70 using a stereomicroscope, optical microscope, laser microscope, or the like.

[0087] 9 is a cross-sectional view of the lid 160 of the first modified example. The lid 160 has a cylindrical barrier member 133 that communicates with the through-hole 71Z. The barrier member 133 is formed by, for example, pressing the base 71.

[0088] The barrier member 133 includes a first barrier member 133A and a second barrier member 133B. The first barrier member 133A extends from the end face of the through-hole 71Z on the second surface 71B side toward the electrode assembly 20. The first barrier member 133A covers at least a portion of the first out-of-hole portion 32B of the insulating member 32. The second barrier member 133B extends from the end face of the through-hole 71Z on the first surface 71A side toward the external space. The second barrier member 133B covers at least a portion of the second out-of-hole portion 32C of the insulating member 32. From the viewpoint of preventing electrical conduction between the terminal body 31 and the first barrier member 133A, it is preferable that the end face 133AX of the first barrier member 133A opposite to the through-hole 71Z is insulated. Examples of a method for insulating the end face 133AX include the methods exemplified in the embodiments. In a first modification, the barrier member 33 may be omitted, and the insulating member 32 may be directly covered with the barrier member 133 .

[0089] <2-2. Second modified example> FIG. 10 is a cross-sectional view of a lid 260 according to a second modified example, which is a modification of the first modified example. In the second modified example, the terminal body 31 is not inserted into the lid 260. In the second modified example, the through-hole 71Z is used to inject the electrolyte of the exterior body 40 or to insert a thermocouple. In the second modified example, the first outer-hole portion 32B of the insulating member 32 may be bonded to the inner circumferential surface of the first barrier member 133A. The second outer-hole portion 32C of the insulating member 32 may be bonded to the inner circumferential surface of the second barrier member 133B.

[0090] <2-3.Third modified example> Fig. 11 is a cross-sectional view of a lid body 360 of a third modified example, which is a modified example of the second modified example. As shown in Fig. 11, when the insulating member 32 does not have the second out-of-hole portion 32C, the lid body 70 may omit the second barrier member 133B.

[0091] <2-4. Fourth Modification> In the above embodiment, when at least the base portion 71 of the lid main body 70 is configured to contain a conductive material, the base portion 71 functions as a barrier member. Fig. 12 is a cross-sectional view of a lid body 460 of a fourth modified example.

[0092] The lid 460 has a base 471. The base 471 is made of a conductive material. An insulating member 32 is bonded to the inner circumferential surface of the through-hole 71Z. The thickness HA of the base 471 is 1.0 mm or greater. From the viewpoint of the base 471 functioning suitably as a barrier member, the thickness HA of the base 471 is preferably 2.0 mm or greater, and more preferably 3.0 mm or greater. If the thickness HA of the base 471 varies in parts, the thickness HA of the base 471 is the thickness of the thickest part. When the thickness HA of the base 471 is 1.0 mm or greater, the time from when at least one of moisture and gas enters the insulating member 32 or the through-hole 71Z from the outside of the exterior body 40 to when the moisture and gas are released into the internal space of the exterior body 40 can be sufficiently delayed.

[0093] <2-5. Fifth Modification> In the above embodiment, the lid body 70 is made of a conductive material, but the lid body 70 may be made of a resin material. When the lid body 70 is made of a resin material, the cover 90 of the lid body 60 may be omitted.

[0094] <2-6. Sixth Variation> In the above embodiment, the wall portion 72 may be omitted from the lid body 70. When the wall portion 72 is omitted from the lid body 70, the covering body 90 may cover at least a part of the side surface of the base portion 71. When the wall portion 72 is omitted from the lid body 70 and the base portion 71 is configured to contain a resin material, the covering body 90 may be omitted and the side surface of the base portion 71 and the heat-sealable resin layer 53 of the exterior film 50 may be joined together.

[0095] <2-7. Seventh Variation> In the above embodiment, the exterior film 50 of the electricity storage device 10 may extend outward beyond at least one of the two lid bodies 60 in the FB direction. The electrode body 20 is sealed by closing the portion of the exterior film 50 that extends outward beyond the lid body 60. The portion of the exterior film 50 that extends beyond the lid body 60 may be folded inward so that the outer surfaces of the exterior film 50 come into contact with each other, as in a Goebel-top container, or may be folded toward any surface of the exterior body 40, as in a brick container. In the sixth modification, it is preferable that the terminal body 31 has a length in the FB direction that is sufficient to be exposed from the closed portion of the exterior film 50.

[0096] <2-8. Eighth Variation> In the above 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. As in the sixth modification, the portion of the exterior film 50 that protrudes outward beyond the electrode body 20 may be folded like a Goebel-top container or a brick-type container.

[0097] <2-9. Ninth Variation> In the above 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.

[0098] <2-10. 10th Variation> In the above embodiment, the electrode body 20 is wrapped in one exterior film 50, but it may be wrapped in two or more exterior films 50. [Explanation of symbols]

[0099] 10: Energy storage device 20: Electrode body 30: Electrode terminal unit 31: Terminal body 32: Insulating material 32A: In-hole placement part 32B: First hole placement part (outside hole placement part) 32C: 2nd hole outside placement part (outside hole placement part) 33: Barrier material 33A: End 40: Exterior body 50: Exterior film 60, 260, 360, 460: Lid 60Z: Lid unit 70: Lid body 71A: 1st page 71B:Second side 71Z:Through hole

Claims

1. A lid used for an exterior body of an electricity storage device, The lid body and a through hole penetrating the lid body; an insulating member including an in-hole portion disposed in the through hole and an out-hole portion connected to the in-hole portion and disposed outside the through hole; a barrier member that covers at least a portion of the outer hole portion of the insulating member, the barrier member has at least one of a moisture barrier property and a gas barrier property higher than that of the insulating member, The lid body is configured to include a conductive material, the barrier member has an end portion opposite to the through hole in a portion covering at least a part of the hole-exterior portion inside the power storage device, The end faces of the end portions of the barrier members are insulated. Lid body.

2. The barrier member is integrally formed with the lid body. The lid according to claim 1 .

3. The barrier member is configured as a separate member from the lid body. The lid according to claim 1 .

4. The barrier member covers at least the end portion of the outer hole portion on the through-hole side. The lid according to any one of claims 1 to 3.

5. An electrode body; 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 lid body is a lid body having a first surface and a second surface opposite the first surface; a through hole penetrating the first surface and the second surface; an insulating member including an in-hole portion disposed in the through hole and an out-hole portion connected to the in-hole portion and disposed outside the through hole; a barrier member that covers at least a portion of the outer hole portion of the insulating member, the barrier member has at least one of a moisture barrier property and a gas barrier property higher than that of the insulating member, The lid body is configured to include a conductive material, the barrier member has an end portion opposite to the through hole in a portion covering at least a part of the hole-exterior portion inside the power storage device, The end faces of the end portions of the barrier members are insulated. Energy storage device.

6. An electrode terminal unit attached to a lid used in an exterior body of an electricity storage device, The terminal body and an insulating member joined to the terminal body; a barrier member covering at least a portion of the insulating member, the barrier member has at least one of a moisture barrier property and a gas barrier property higher than that of the insulating member, The lid body is The lid body and a through hole that penetrates the lid body, the insulating member includes an in-hole portion disposed in the through hole, and an out-hole portion connected to the in-hole portion and disposed outside the through hole, the barrier member covers at least a portion of the outer hole portion of the insulating member; The lid body is configured to include a conductive material, the barrier member has an end portion opposite to the through hole in a portion covering at least a part of the hole-exterior portion inside the power storage device, The end faces of the end portions of the barrier members are insulated. Electrode terminal unit.

7. A method for manufacturing an electricity storage device, comprising: The electricity storage device is An electrode body; 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 lid body is The lid body and a through hole penetrating the lid body; an insulating member including an in-hole portion disposed in the through hole and an out-hole portion connected to the in-hole portion and disposed outside the through hole; a barrier member that covers at least a portion of the outer hole portion of the insulating member, the barrier member has at least one of a moisture barrier property and a gas barrier property higher than that of the insulating member, The lid body is configured to include a conductive material, the barrier member has an end portion opposite to the through hole in a portion covering at least a part of the hole-exterior portion inside the power storage device, The end surface of the end of the barrier member is insulated, The method for manufacturing the electricity storage device includes: and a step of placing the lid body on the electrode body. A method for manufacturing an electricity storage device.

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