Lid, power storage device, and method for manufacturing power storage device

Abstract

To provide a lid body suppressed from being deformed, a power storage device including the lid body, and a method of manufacturing the power storage device.SOLUTION: The lid is a lid constituting an exterior body of the power storage device. The lid includes a base portion, a wall portion protruding from the base portion, and a rib extending from one of the base portion and the wall portion toward the other.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a lid, an electricity storage device, 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 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. [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 power storage device, if the lid is deformed, for example, the lid and the exterior film cannot be properly joined, and the sealing performance of the exterior film may be reduced. Note that deformation of the lid occurs, for example, due to the application of an external force to the lid, or due to molding defects when the lid is manufactured by injection molding.

[0005] An object of the present invention is to provide a lid body that is suppressed from deforming, an electricity storage device including this lid body, and a method for manufacturing this 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 that constitutes an outer casing of an electricity storage device, and includes a base, a wall portion protruding from the base, and a rib extending from one of the base and the wall portion toward the other.

[0007] A lid according to a second aspect of the present invention is the lid according to the first aspect, wherein the rib contacts the base and the wall.

[0008] A lid according to a third aspect of the present invention is the lid according to the first or second aspect, wherein the rib is joined to at least one of the base and the wall.

[0009] A lid body according to a fourth aspect of the present invention is a lid body according to any one of the first to third aspects, wherein the wall portion has a first wall surface joined to an exterior film that is an element constituting the exterior body, and a second wall surface opposite the first wall surface, and the rib extends from the base and one of the second wall surfaces toward the other.

[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 base has an output section comprising a conductive material and a covering section comprising a resin material and covering a portion of the output section.

[0011] A sixth 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 that seals the electrode body together with the exterior film, and the lid body comprises a base, a wall that protrudes from the base and is joined to the exterior film, and a rib that extends from one of the base and the wall toward the other.

[0012] A seventh 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 having a base, a wall portion protruding from the base and joined to the exterior film, and a rib extending from one of the base and the wall portion toward the other. The method for manufacturing an electricity storage device includes a step of arranging the lid body on the electrode assembly. [Effects of the Invention]

[0013] According to the lid, the electricity storage device, and the method for manufacturing the electricity storage device of the present invention, deformation of the lid can be suppressed. [Brief explanation of the drawings]

[0014] [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] FIG. 1B is a perspective view of a lid provided in the electricity storage device of FIG. 1A. [Figure 5] 1B is a cross-sectional view taken along line D5-D5 in FIG. 1A. [Figure 6] 1B is a flowchart showing an example of a method for manufacturing the electricity storage device of FIG. 1A. [Figure 7] FIG. 10 is a cross-sectional view of a lid provided in an electricity accumulation device according to a first modified example. [Figure 8] FIG. 11 is a cross-sectional view of a lid provided in an electricity accumulation device according to a second modified example. [Figure 9] FIG. 11 is a cross-sectional view of a lid provided in an electricity accumulation device according to a third modified example. [Figure 10] FIG. 11 is a cross-sectional view of a lid provided in an electricity accumulation device according to a fourth modified example. [Figure 11] FIG. 13 is a cross-sectional view of a lid provided in another example of an electricity accumulation device according to the fourth modified example. [Figure 12] FIG. 13 is a cross-sectional view of a base portion of a lid body included in an electricity accumulation device according to a fifth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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.

[0016] [Embodiment] <1-1. Configuration of the power storage device> FIG. 1A is a plan view schematically showing an electricity storage device 10 of an embodiment. FIG. 1B is a diagram showing 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 showing the layer structure of an exterior film 50 provided in the electricity storage device 10 of FIG. 1A. FIG. 3 is a diagram showing the exterior film 50 provided in the electricity storage device 10 of FIG. 1A in an unfolded state. FIG. 4 is a perspective view of a lid body 60 provided in the electricity storage device 10 of FIG. 1A. FIG. 5 is a cross-sectional view taken along line D5-D5 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 the subsequent figures.

[0017] The electricity storage device 10 includes an electrode assembly 20 including a current collector 30 and an exterior housing 40. The electrode assembly 20 includes electrodes (positive and negative electrodes) constituting an electricity storage component such as a lithium-ion battery, capacitor, all-solid-state battery, semi-solid battery, quasi-solid battery, polymer battery, all-resin battery, lead-acid battery, nickel-metal hydride battery, nickel-cadmium battery, nickel-iron battery, nickel-zinc battery, silver oxide-zinc battery, metal-air battery, polycation battery, or 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. The electrode assembly 20 may have a cylindrical or polygonal prism shape, for example. One end 31 of the current collector 30 (see FIG. 5 ) is connected to an output section 71 of the lid 60, which will be described later.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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 occurring 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.

[0024] 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.

[0025] 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.

[0026] 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 specified in JIS H4160:1994A8021H-H18, JIS H4160:1994A8079H-H18, JISH4000:2014A8021P-H14, or JIS H4000:2014A8079P-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 specified in JIS H4000:2017 A5005P-O, JIS H4000:2017 A5050P-O, and JISH4000:2017 A5052P-O.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The lid 60 has a base 70 , a wall 80 , and a rib 90 .

[0038] The outer shape of the base 70 can be selected arbitrarily as long as it can seal the electrode assembly 20. In the example shown in FIG. 4 etc., the outer shape of the base 70 is rectangular. The outer shape of the base 70 may be circular, elliptical, square, triangular, or a polygon with pentagons or more sides. The base 70 has a first surface 70A and a second surface 70B. The first surface 70A faces the external space. The second surface 70B is the surface opposite the first surface 70A in the FB direction. The second surface 70B faces the electrode assembly 20. The lid 60 may be arranged so that the first surface 70A faces the electrode assembly 20, in other words, so that the second surface 70B faces the external space. The base 70 includes an output section 71 and a covering section 72.

[0039] The output unit 71 is an element that outputs power to an external device. The output unit 71 is connected to one end 31 of the current collector 30. The outer shape of the output unit 71 can be selected arbitrarily. In the example shown in FIG. 4 etc., the outer shape of the output unit 71 is rectangular.

[0040] In this embodiment, the output section 71 is composed of a conductive material. "Composed of a conductive material" means that, when the entire material constituting the output section 71 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 output section 71 can contain, in addition to the conductive material, materials other than the conductive material. The output section 71 composed of a conductive material preferably has the corrosion-resistant coating described for the barrier layer 52.

[0041] The conductive material constituting the output unit 71 is, for example, a metal material. The metal material constituting the output unit 71 is, for example, aluminum, aluminum alloy, nickel, copper, or copper alloy. For example, when the electrode body 20 is a lithium ion battery, the output unit 71 connected to the positive electrode is preferably made of aluminum or an aluminum alloy. The output unit 71 connected to the negative electrode is preferably made of nickel, copper, or a copper alloy. The material constituting the output unit 71 connected to the negative electrode may be copper plated with nickel. The material constituting the output unit 71 may include recycled metal materials.

[0042] The covering portion 72 covers a portion of the output portion 71. In the example shown in FIG. 4 etc., the covering portion 72 covers the entire outer periphery of the output portion 71. The outer shape of the covering portion 72 can be selected arbitrarily. In the example shown in FIG. 4 etc., the outer shape of the covering portion 72 is rectangular. A through-hole 72X is formed in the center of the covering portion 72, penetrating the first surface 70A and the second surface 70B.

[0043] In this embodiment, the covering portion 72 is made up of a resin material. Here, "made up of a resin material" means that, when the entire material constituting the covering portion 72 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 portion 72 can contain materials other than the resin material in addition to the resin material.

[0044] 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 portion 72 may be molded by any molding method or manufactured by cutting.

[0045] The resin material contained in the material constituting the covering portion 72 is preferably an olefin-based random copolymer, more preferably a resin containing a polyolefin skeleton as a main component, even more preferably a polyolefin as a main component, and even more preferably a polypropylene as a main component. The polyolefin may be an acid-modified polyolefin. The resin material contained in the material constituting the covering portion 72 preferably contains multiple types of amide-based lubricants. Furthermore, the resin material contained in the material constituting the covering portion 72 preferably contains, in addition to saturated fatty acid amide, multiple types of amide-based lubricants further containing unsaturated fatty acid amide. The resin material contained in the material constituting the covering portion 72 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.

[0046] 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.

[0047] 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.

[0048] 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 portion 72 to temperature changes can be improved.

[0049] The melt mass flow rate of the resin material contained in the material constituting the covering portion 72 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 melt mass flow rate is measured at 230°C.

[0050] The thickness of the output section 71 in the FB direction and the thickness of the covering section 72 can be selected arbitrarily. The thickness of the output section 71 in the FB direction may be thicker than the thickness of the covering section 72, may be thinner than the thickness of the covering section 72, or may be equal to the thickness of the covering section 72. In the example shown in FIG. 4 etc., the thickness of the output section 71 in the FB direction is substantially equal to the thickness of the covering section 72 in the FB direction. In other words, the first surface 70A of the output section 71 and the first surface 70A of the covering section 72 are flush with each other. The second surface 70B of the output section 71 and the second surface 70B of the covering section 72 are flush with each other.

[0051] The wall portion 80 protrudes from the outer peripheral edge of the covering portion 72. The direction in which the wall portion 80 protrudes can be selected arbitrarily. In the example shown in FIG. 5 etc., the wall portion 80 protrudes from the outer peripheral edge of the covering portion 72 toward the electrode body 20 in the FB direction. The wall portion 80 may protrude from the outer peripheral edge of the covering portion 72 in the opposite direction to the electrode body 20, in other words, toward the external space, in the FB direction. The wall portion 80 may protrude from the outer peripheral edge of the covering portion 72 in a direction intersecting the FB direction in a side view of the lid body 60.

[0052] The wall portion 80 is preferably made up of a resin material. The definition of "made up of a resin material" with respect to the wall portion 80 is the same as the definition of "made up of a resin material" with respect to the covering portion 72. The resin material contained in the material that makes up the wall portion 80 can be any of the resin materials exemplified as being contained in the material that makes up the covering portion 72. From the viewpoint of easily molding the lid body 60, it is preferable that the resin material contained in the material that makes up the wall portion 80 and the resin material contained in the material that makes up the covering portion 72 are the same.

[0053] The wall portion 80 has a first wall surface 80A and a second wall surface 80B. The first wall surface 80A is the surface that is joined to the exterior film 50. In this embodiment, the first wall surface 80A is joined to the heat-fusible resin layer 53 of the exterior film 50 by heat sealing. The first wall surface 80A may also be joined to the exterior film 50 with an adhesive. The second wall surface 80B is the surface opposite to the first wall surface 80A.

[0054] The wall portion 80 includes a first joint wall 81, a second joint wall 82, a third joint wall 83, and a fourth joint wall 84. The first joint wall 81 constitutes the upper surface of the lid body 60. The first joint wall 81 extends in a first direction (in the present embodiment, the LR direction) in a front view of the lid body 60. The second joint wall 82 and the third joint wall 83 are connected to the first joint wall 81 and constitute the side surfaces of the lid body 60. The second joint wall 82 and the third joint wall 83 extend in a second direction (in the present embodiment, the UD direction) that intersects with the first direction in a front view of the lid body 60. In the present embodiment, the first direction and the second direction are orthogonal in a front view of the lid body 60. The first direction and the second direction do not have to be orthogonal in a front view of the lid body 60. The fourth joint wall 84 constitutes the lower surface of the lid body 60. The fourth joint wall 84 extends in a first direction (LR direction in this embodiment) when the lid body 60 is seen from the front.

[0055] In the present embodiment, the thicknesses of the first to fourth joining walls 81 to 84 are substantially constant in the FB direction. The thicknesses of the first to fourth joining walls 81 to 84 may vary in the FB direction. For example, at least one of the first to fourth joining walls 81 to 84 may have a tapered shape in which the thickness increases or decreases in the FB direction toward the electrode assembly 20. When the first to fourth joining walls 81 to 84 have a tapered shape, the tapered shape preferably increases in thickness toward the electrode assembly 20, from the viewpoint of suppressing an increase in the internal pressure of the exterior body 40. From the viewpoint of suppressing a decrease in the strength of the lid body 60, the first and fourth joining walls 81 and 84, which are longer in the LR direction among the wall portions 80, preferably have a constant thickness in the FB direction, in other words, do not have a tapered shape.

[0056] The wall portion 80 further includes boundaries 85, 86, 87, and 88. The boundary 85 is the boundary between the first joining wall 81 and the second joining wall 82. The boundary 86 is the boundary between the first joining wall 81 and the third joining wall 83. The boundary 87 is the boundary between the fourth joining wall 84 and the second joining wall 82. The boundary 88 is the boundary between the fourth joining wall 84 and the third joining wall 83. The boundaries 85 to 88 may have angular shapes or may be rounded by being subjected to rounding. In this embodiment, the boundaries 85 to 88 are angular. If the boundaries 85 to 88 are rounded, the radius of curvature of the boundaries 85 to 88 is preferably in the range of more than 0 mm and not more than 0.5 mm.

[0057] The lid 60 preferably has a certain degree of thickness so that deformation of the exterior body 40 is suppressed even when the power storage devices 10 are stacked. The minimum thickness of the covering portion 72 and the wall portion 80 of the lid 60 is, for example, 0.3 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum thickness of the covering portion 72 and the wall portion 80 of the lid 60 is, for example, 20 mm, more preferably 15 mm, more preferably 10 mm, and even more preferably 7.0 mm. The maximum thickness of the covering portion 72 and the wall portion 80 of the lid 60 may be 20 mm or more. The preferred ranges for the thickness of the covering portion 72 and the wall portion 80 of the lid body 60 are 0.3 mm to 20 mm, 0.3 mm to 15 mm, 0.3 mm to 10 mm, 0.3 mm to 7.0 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 10 mm, 3.0 mm to 7.0 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, 4.0 mm to 10 mm, and 4.0 mm to 7.0 mm. This embodiment does not include embodiments in which the covering portion 72 and the wall portion 80 are composed solely of a film as defined by the JIS (Japanese Industrial Standards) "Packaging Terminology" standard. The thicknesses of the covering portion 72 and the wall portion 80 of the lid body 60 may vary depending on the location. For example, if the thickness of the covering portion 72 of the lid body 60 varies depending on the location, the thickness of the covering portion 72 of the lid body 60 is the thickness of the thickest portion of the covering portion 72. For example, if the thickness of the wall portion 80 of the lid body 60 varies depending on the location, the thickness of the wall portion 80 of the lid body 60 is the thickness of the thickest portion of the wall portion 80.

[0058] The lid 60 may be deformed relative to one of the base 70 and the wall 80 due to, for example, an external force acting on the lid 60 or a molding defect when the lid 60 is injection molded. The rib 90 has the function of suppressing deformation of the lid 60.

[0059] The rib 90 extends from one of the base 70 and the wall 80 to the other. From the viewpoint of suitably suppressing deformation of the lid 60, the rib 90 preferably extends from one of the second surface 70B of the base 70 and the second wall surface 80B of the wall 80 to the other. The rib 90 may extend from one of the second surface 70B of the base 70 and any part of the wall 80 to the other. From the viewpoint of suitably suppressing deformation of the lid 60, the rib 90 is preferably in contact with the base 70 and the wall 80. The rib 90 does not have to be in contact with the base 70 or the wall 80. From the viewpoint of suitably suppressing deformation of the lid 60, the rib 90 is preferably joined to at least one of the base 70 and the wall 80. The rib 90 does not have to be joined to the base 70 or the wall 80. In the present embodiment, the rib 90 is joined to the base 70 and the wall 80.

[0060] The number of ribs 90 included in one lid body 60 can be selected arbitrarily. In the example shown in FIG. 4, one lid body 60 has 16 ribs 90. In the example shown in FIG. 4, the second wall surface 80B of the first joint wall 81 and the second surface 70B of the covering portion 72 are connected by five ribs 90. The second wall surface 80B of the second joint wall 82 and the second surface 70B of the covering portion 72 are connected by three ribs 90. The second wall surface 80B of the third joint wall 83 and the second surface 70B of the covering portion 72 are connected by three ribs 90. The second wall surface 80B of the fourth joint wall 84 and the second surface 70B of the covering portion 72 are connected by five ribs 90. The ribs 90 may extend from one side of the wall portion 80 and the second surface 70B of the output portion 71 to the other side. One lid 60 may have 1 to 15, or 17 or more, ribs 90.

[0061] When one lid body 60 has multiple ribs 90, it is possible to arbitrarily select the interval between adjacent ribs 90. From the viewpoint of suitably suppressing deformation of the lid body 60, the interval between adjacent ribs 90 is preferably 15 mm or less, and more preferably 10 mm or less.

[0062] When the rib 90 extends from the second wall surface 80B, the rib 90 can be formed at any position on the second wall surface 80B. From the viewpoint of formability of the lid body 60, it is preferable that the rib 90 not be formed at the corners of the boundary of the second wall surface 80B of the continuous wall portion 80.

[0063] The shape of the rib 90 can be selected arbitrarily as long as it is a shape that can suppress deformation of the lid body 60. In the example shown in FIG. 4 etc., the shape of the rib 90 is a triangular plate. In this embodiment, any one side of the rib 90 is entirely joined to the second wall surface 80B of the wall portion 80. Any other one side of the rib 90 is entirely joined to the second surface 70B of the covering portion 72. The shape of the rib 90 may be a circular plate, an elliptical plate, a rectangular plate, or a polygonal plate with pentagons or more sides. When one lid body 60 has multiple ribs 90, the shapes of the multiple ribs 90 may be the same, or at least one of the ribs 90 may be different.

[0064] The thickness of the rib 90 can be selected arbitrarily as long as it is thick enough to suppress deformation of the lid 60. From the viewpoint of formability of the lid 60, the thickness of the rib 90 is preferably thinner than the thickness of the wall portion 80. The thickness of the rib 90 is preferably two-thirds or less, more preferably one-half or less, of the thickness of the wall portion 80. When the thickness of the rib 90 is thinner than the thickness of the wall portion 80, deformation of the wall portion 80 during manufacturing of the lid 60 can be suppressed. Since unevenness is less likely to be formed on the first wall surface 80A of the lid 60, adhesion between the lid 60 and the exterior film 50 is improved. The thickness of the rib 90 provided on the first joint wall 81 or the fourth joint wall 84 is the thickness in the LR direction. The thickness of the rib 90 provided on the second joint wall 82 or the third joint wall 83 is the thickness in the UD direction.

[0065] The method for manufacturing the lid 60 can be selected arbitrarily. For example, the lid 60 may be manufactured by injection molding the covering portion 72, the wall portion 80, and the rib 90 onto the output portion 71. In another example, the covering portion 72 may be injection molded onto the output portion 71, and the wall portion 80 and the rib 90 may be joined thereto. In yet another example, the covering portion 72 and the wall portion 80 may be injection molded onto the output portion 71, and the rib 90 may be joined thereto. In yet another example, after the covering portion 72, the wall portion 80, and the rib 90 are injection molded, the output portion 71 may be placed in the through-hole 72X, and the output portion 71 and the covering portion 72 may be joined thereto. At least one of the output portion 71, the covering portion 72, the wall portion 80, and the rib 90 may be manufactured by cutting.

[0066] 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.

[0067] 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 100AX of the first sealed portion 100A is preferably located on a 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.

[0068] In this embodiment, the second sealed portion 100B is formed by heat-sealing the heat-sealable resin layer 53 of the exterior film 50 and the first wall surface 80A of the lid 60. Hereinafter, the seal strength between the heat-sealable resin layer 53 of the exterior film 50 and the first wall surface 80A of the lid 60 may be referred to as the seal strength (bonding strength) of the second sealed portion 100B. The seal strength of the second sealed portion 100B is the seal strength between the heat-sealable resin layer 53 and the lid 60 at the long side portion of the first wall surface 80A, i.e., the first wall surface 80A extending in the L-R (width) direction in FIG. 1A.

[0069] 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 41B) to measure 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. 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 100B is the sealing strength of the long side portions of the first wall surfaces 80A of the multiple parts.

[0070] 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.

[0071] <1-2. Method for manufacturing electricity storage devices> FIG. 6 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 some 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.

[0072] 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.

[0073] The second step of step S12 is performed after the first step. In the second step, the manufacturing device joins the current collector 30 and the output portion 71 of the lid 60 together.

[0074] 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 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 current collector 30 and the output section 71 are joined, the opening may be closed with the lid 60. In yet another example, the electrode body 20 connected to the output section 71 of 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 with the lid 60.

[0075] The fourth step of step S14 is performed after the third step. In the fourth step, the manufacturing apparatus heat-seals the exterior film 50 and the first wall surface 80A of the lid body 60 to form the second sealed portion 110B.

[0076] 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.

[0077] <1-3. Actions and Effects of Electricity Storage Devices> The electricity storage device 10 includes a lid 60. The lid 60 has ribs 90 extending from one of the base 70 and the wall 80 to the other. Therefore, the lid 60 suppresses deformation of either the base 70 or the wall 80 relative to the other.

[0078] [2. Modifications] The above-described embodiments are examples of possible forms of the lid body, the electricity storage device, and the method for manufacturing the electricity storage device according to the present invention, and are not intended to limit the forms. The lid body, the electricity storage device, and the method for manufacturing the electricity storage device 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 the embodiments is replaced, changed, 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.

[0079] <2-1. First modified example> In the above embodiment, the configuration of the lid 60 can be changed. Fig. 7 is a cross-sectional view of a lid 160 provided in the electricity storage device 10 of the first modified example.

[0080] The lid body 160 includes a base 170. The lid body 160 may be arranged so that a first surface 70A of the base 170 faces the external space, and so that a second surface 70B faces the electrode body 20. The base 170 may be substantially entirely made of a conductive material.

[0081] <2-2. Second modified example> FIG. 8 is a cross-sectional view of a lid 260 provided in the electricity accumulation device 10 of the second modified example. The lid 260 has a first element 270, a second element 280, and a rib 290.

[0082] The first element 270 is preferably made of, for example, a conductive material. When the first element 270 is made of, for example, a conductive material, the first element 270 is preferably connected to one end 31 of the current collector 30 of the electrode body 20. The first element 270 has a base 271 and a wall 272. The outer shape of the base 271 is, for example, rectangular. The wall 272 protrudes from the outer periphery of the base 271 toward the electrode body 20 in the FB direction. The wall 272 is preferably made of, for example, a conductive material.

[0083] The second element 280 is preferably made of, for example, a resin material. The second element 280 covers a part of the first element 270. The second element 280 has a base portion 281 and a wall portion 282.

[0084] Base portion 281 covers parts of first surface 70A and second surface 70B of base portion 271 and part of wall portion 272. Wall portion 282 is connected to base portion 281 and covers part of wall portion 272. Wall portion 282 protrudes toward electrode body 20 in the FB direction.

[0085] The rib 290 is preferably made of, for example, a resin material. The rib 290 extends from one of the base 281 and the wall 282 toward the other. In the example shown in Fig. 8, the rib 290 is joined to the base 281 and the wall 282. In the second modified example, the lid 260 may be disposed so that the first surface 70A of the base 271 faces the electrode body 20.

[0086] <2-3.Third modified example> FIG. 9 is a cross-sectional view of a lid 360 provided in the electricity accumulation device 10 of the third modified example. The lid 360 has a first element 370, a second element 380, and a rib 390.

[0087] The first element 370 is preferably configured to include, for example, a conductive material. When the first element 370 is configured to include a conductive material, the first element 370 is preferably connected to one end 31 of the current collector 30 of the electrode body 20. The outer shape of the first element 370 is, for example, rectangular.

[0088] The second element 380 is preferably made of, for example, a resin material. The second element 380 covers a part of the first element 370. The second element 380 has a base portion 381 and a wall portion 382.

[0089] The base 381 covers parts of the first surface 70A and the second surface 70B of the first element 370, as well as the outer peripheral edge of the first element 370. The base 381 preferably covers the entire outer peripheral edge of the first element 370. The wall 382 is connected to the base 381 and protrudes toward the external space in the FB direction.

[0090] The rib 390 is preferably made of, for example, a resin material. The rib 390 extends from one of the base 381 and the wall 382 toward the other. In the example shown in Fig. 9, the rib 390 is joined to the base 381 and the wall 382. In the third modified example, the cover 360 may be arranged so that the first surface 70A of the first element 370 faces the electrode body 20.

[0091] <2-4. Fourth Modification> FIG. 10 is a cross-sectional view of a lid 460 provided in the electricity accumulation device 10 of the fourth modified example. The lid 460 has a base 470, a wall 480, and a rib 490. The entire lid 460 may be made of, for example, a resin material.

[0092] The outer shape of the base 470 is, for example, rectangular. The wall 480 protrudes from the outer periphery of the base 470 toward the external space in the FB direction. The rib 490 extends from one of the base 470 and the wall 480 to the other. In the example shown in Fig. 10, the rib 490 is joined to the base 470 and the wall 480.

[0093] A barrier film 400 having a moisture barrier function may be bonded to at least a portion of the first surface 70A and the second surface 70B of the base 470. In the example shown in Fig. 10, the barrier film 400 is bonded to substantially the entire second surface 70B of the base 470. The barrier film 400 is a film including at least a barrier layer 52. The barrier film 400 may be bonded to at least a portion of the first wall surface 80A.

[0094] When the base 470 and wall 480 of the lid 460 are made to contain a resin material as in the fourth modified example, the electricity storage device 10 preferably has an electrode terminal 400X for outputting electric power to the outside. The electrode terminal 400X is joined to one end 31 of the current collector 30. As shown in FIG. 10 , the electrode terminal 400X may be disposed between the first wall surface 80A of the wall 480 and the exterior film 50 (not shown). As shown in FIG. 11 , the electrode terminal 400X may be disposed so as to penetrate the base 470 of the lid 460. Note that in the fourth modified example, the lid 460 may be disposed so that the first surface 70A of the base 470 faces the electrode body 20.

[0095] <2-5. Fifth Modification> In the above embodiment, the thickness of the base 70 is substantially constant, but the thickness of the base 70 may vary partially. As shown in Fig. 12, for example, the covering portion 72 of the base 70 may include a thin portion 72A and a thick portion 72B. The thin portion 72A is formed within a predetermined range from the outer peripheral edge of the base 70. It is preferable that the rib 90 extend from one of the thin portion 72A and the wall portion 80 to the other.

[0096] <2-6. Sixth Variation> In the above embodiment, the entire base 70, the wall 80, and / or the rib 90 may be configured to include a conductive material. When the wall 80 is configured to include a conductive material, the first wall surface 80A and the exterior film 50 are preferably joined via an adhesive film that is suitably bonded to conductive materials and resin materials.

[0097] The adhesive film can be any film capable of adhering the exterior film 50 and the wall portion 80. 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 materials, 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 wall portion 80. The material constituting the heat-sealable resin layer of the adhesive film on the side bonded to the wall portion 80 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 bonded to the exterior film 50 is preferably made of the same material as the material constituting the heat-sealable resin layer 53 of the exterior film 50.

[0098] 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.

[0099] The adhesive film preferably has adhesive properties. When the adhesive film has adhesive properties, the adhesive film is less likely to shift position relative to the lid body 60 and the exterior film 50 when the second sealing portion 100B is formed with the adhesive film disposed between the exterior film 50 and the wall portion 80. 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 wt % or less.

[0100] <2-7. Seventh Variation> In the above embodiment, the exterior film 50 of the electricity storage device 10 may protrude 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 protrudes outward beyond the lid body 60. The portion of the exterior film 50 that protrudes beyond the lid body 60 may be folded inward so that the outer surfaces of the exterior films 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.

[0101] <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 seventh 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 container.

[0102] <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.

[0103] <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]

[0104] 10: Energy storage device 20: Electrode body 40: Exterior body 50: Exterior film 60, 260, 360, 460, 560: Lid 70, 171, 181, 271, 281, 381, 470, 570: Base 71: Output section 72: Covering part 80, 172, 182, 272, 282, 382, ​​480, 580: Wall 80A: First wall 80B: Second wall 90, 190, 290, 390, 490, 590: Rib 491: First Rib 492: Second Rib

Claims

1. A lid body that is one of the components that make up an outer casing for an electricity storage device and seals an electrode body, the outer casing for the electricity storage device includes an outer casing film that wraps the electrode assembly so as to have an opening, In each component constituting the outer casing for the power storage device, the side facing the electrode body is defined as an inner side, the side opposite to the side facing the electrode body is defined as an outer side, and the direction perpendicular to the opening is defined as a depth direction, The lid is disposed at the opening, The lid body includes a base portion whose outer shape in a plan view in the depth direction follows an inner periphery of the opening portion; a wall portion protruding from the base portion in the depth direction; a rib joined to the base and the wall; the base has an outer surface and an inner surface; The wall portion has a first wall surface joined to the exterior film and a second wall surface opposite to the first wall surface, the rib includes a plurality of plate-like ribs arranged at a joining position where the inner surface of the base portion and the second wall surface of the wall portion join together, the plate-like rib has an outer periphery surrounded by a first side and a second side originating from the joining position, and other sides connecting end portions of the first side and the second side located on the opposite side from the joining position, the entire first side of the plate-like rib is joined to the second wall surface of the wall portion, the entire second side of the plate-like rib is joined to the inner surface of the base, The other side of the plate-like rib is one or more continuous sides having an end of the first side located on the opposite side to the joining position as one end and an end of the second side located on the opposite side to the joining position as the other end, and does not come into contact with the lid body except for the one end and the other end. Lid body.

2. A lid body that is one of the components that make up an outer casing for an electricity storage device and seals an electrode body, the outer casing for the electricity storage device includes an outer casing film that wraps the electrode assembly so as to have an opening, In each component constituting the outer casing for the power storage device, the side facing the electrode body is defined as an inner side, the side opposite to the side facing the electrode body is defined as an outer side, and the direction perpendicular to the opening is defined as a depth direction, The lid is disposed at the opening, The lid body includes a base portion whose outer shape in a plan view in the depth direction is shaped to follow the inner periphery of the opening portion; a wall portion protruding from the base portion in the depth direction; a rib joined to the base and the wall; the base has an outer surface and an inner surface; The wall portion has a first wall surface joined to the exterior film and a second wall surface opposite to the first wall surface, the rib includes a plurality of plate-like ribs arranged at a joining position where the outer surface of the base portion and the second wall surface of the wall portion join together, the plate-like rib has an outer periphery surrounded by a first side and a second side originating from the joining position, and other sides connecting end portions of the first side and the second side located on the opposite side from the joining position, the entire first side of the plate-like rib is joined to the second wall surface of the wall portion, the second side of the plate-like rib is entirely joined to the outer surface of the base, The other side of the plate-like rib is one or more continuous sides having an end of the first side located on the opposite side to the joining position as one end and an end of the second side located on the opposite side to the joining position as the other end, and does not come into contact with the lid body except for the one end and the other end. Lid body.

3. The lid body is a first element comprising a conductive material; a second element including a resin material; The rib is made of a resin material, The first element is a base of a first element whose outer shape in a plan view in the depth direction follows an inner periphery of the opening; a wall portion of the first element protruding in the depth direction from a base portion of the first element, The base of the first element comprises: the outer surface of the base of the first element; the inner surface of the base of the first element; The wall of the first element comprises: a first wall surface of the wall portion of the first element facing the exterior film; a second wall surface of the first element wall opposite the first wall surface of the first element wall, The second element is covering a portion of the base of the first element and a portion of the wall of the first element; the second wall surface of the wall portion to which the entire first side of the plate-like rib is joined; The outer surface or the inner surface of the base to which the entire second side of the plate-like rib is joined is made of the second element. The lid according to claim 1 or 2.

4. The lid body is a first element comprising a conductive material; a second element including a resin material; The rib is made of a resin material, the first element has a base portion whose outer shape in a plan view in the depth direction follows an inner periphery of the opening, The base of the first element comprises: an outer surface of the base of the first element; an inner surface of the base of the first element; The second element is covering a portion of the base of the first element; The second element is a base of the second element; a wall portion of the second element protruding in a depth direction from a base portion of the second element, The base of the second element comprises: a portion of an outer surface of the base of the first element; a portion of an inner surface of the base of the first element; and covering the entire outer periphery of the base of the first element; The wall of the second element comprises: a first wall surface of the wall portion of the second element facing the exterior film; a second wall surface of the second element wall opposite the first wall surface of the second element wall, the second wall surface of the wall portion to which the entire first side of the plate-like rib is joined; The outer surface or the inner surface of the base to which the entire second side of the plate-like rib is joined is made of the second element. The lid according to claim 1 or 2.

5. An electrode body; an outer casing for an electricity storage device that seals the electrode body, The outer casing for the electricity storage device includes an outer casing film that wraps the electrode body; and a lid according to claim 1 or 2 that seals the electrode assembly together with the exterior film. Energy storage device.

6. A method for manufacturing an electricity storage device, comprising: The electricity storage device is An electrode body; an outer casing for an electricity storage device that seals the electrode assembly, The outer casing for the electricity storage device is an exterior film that wraps the electrode body; and a lid according to claim 1 or 2 that seals the electrode assembly together with the exterior film, 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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