Electricity storage device and method for producing same

Abstract

The power storage device includes an electrode body, an exterior film, a sealing portion, and a sealing reinforcement portion. The exterior film envelops the electrode body to form an opening and has a first sealing area. A lid body is disposed in the opening and has a second sealing area facing the first sealing area. The sealing portion is formed between the first sealing area and the second sealing area, and at least partially seals between the first sealing area and the second sealing area. The sealing reinforcement portion reinforces the sealing provided by the sealing portion.

Description

[Technical field]

[0001] The present invention relates to an electricity storage device and a manufacturing method thereof. [Background technology]

[0002] Patent Document 1 discloses an all-solid-state battery as an example of an electricity storage device. This all-solid-state battery includes an electrode body, an electrode terminal, and an exterior body that seals the electrode body. The exterior body includes an exterior film that is wrapped around the electrode body to have an opening, and a lid body that is placed on the opening. One end of the electrode terminal is electrically connected to the electrode body. The other end of the electrode terminal is exposed to the outside of the lid body. The electrode terminal penetrates the lid body. The side of the lid body and the exterior film are bonded via a sealant layer formed thereon or via an adhesive layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-153504 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an electricity storage device such as that in Patent Document 1, from the viewpoint of reliably sealing between the lid and the exterior film, it is preferable that the side dimensions of the lid and the exterior film facing the side of the lid are the same. However, in reality, there may be a difference between the two dimensions, and such a difference may lead to poor sealing between the lid and the exterior film. Patent Document 1 does not take this into consideration.

[0005] An object of the present invention is to provide an electricity storage device with improved sealing performance between a lid and an exterior film. [Means for solving the problem]

[0006] The power storage device according to a first aspect of the present invention comprises an electrode body, an exterior film, a lid body, a seal portion, and a seal reinforcement portion. The exterior film envelops the electrode body to form an opening, and has a first seal area. The lid body is disposed in the opening, and has a second seal area facing the first seal area. The seal portion is formed between the first seal area and the second seal area, and at least partially seals between the first seal area and the second seal area. The seal reinforcement portion reinforces the sealing provided by the seal portion.

[0007] An electricity storage device according to a second aspect of the present invention is the electricity storage device according to the first aspect, wherein the material forming the seal reinforcement portion includes at least one of a resin, a metal, a ceramic, and a rubber, a mixture of at least two of these, and a composite of at least two of these.

[0008] An energy storage device according to a third aspect of the present invention is an energy storage device according to the first or second aspect, wherein the seal reinforcement portion is formed between the first seal area and the second seal area, at least in a portion where the seal portion is not formed.

[0009] An energy storage device according to a fourth aspect of the present invention is an energy storage device according to any one of the first to third aspects, wherein the lid body has a polygonal shape having an apex when viewed from the front, and the seal reinforcement portion is formed so as to at least partially cover at least one apex of the polygonal shape of the lid body from the outside.

[0010] An electricity storage device according to a fifth aspect of the present invention is an electricity storage device according to any one of the first to fourth aspects, wherein the seal reinforcement portion covers at least a portion of the first seal area and at least a portion of the second seal area from the outside of the exterior film and the lid body.

[0011] An electricity storage device according to a sixth aspect of the present invention is an electricity storage device according to any one of the first to fifth aspects, wherein the electrode body has a three-dimensional shape including a plurality of corners, and the seal reinforcement portion covers at least one of the plurality of corners from the outside of the exterior film.

[0012] An electricity storage device according to a seventh aspect of the present invention is an electricity storage device according to any one of the first to sixth aspects, wherein the electrode body has a three-dimensional shape including two faces that intersect with each other and a ridge portion formed by the two faces, and the seal reinforcement portion covers the ridge portion from the outside of the exterior film.

[0013] A manufacturing method for an energy storage device according to an eighth aspect of the present invention includes preparing an electrode body, wrapping the electrode body with an exterior film having a first sealing area to form an opening, placing a lid body having a second sealing area at the opening so that the second sealing area faces the first sealing area, forming a seal portion between the first sealing area of ​​the exterior film and the second sealing area of ​​the lid body, which at least partially seals the area between the first sealing area and the second sealing area, and forming a seal reinforcement portion between the first sealing area and the second sealing area, at least in a portion where the seal portion is not formed, which reinforces the seal portion.

[0014] A manufacturing method for an electricity storage device according to a ninth aspect of the present invention includes preparing an electrode body, wrapping the electrode body with an exterior film having a first sealing area to form an opening, placing a lid body having a second sealing area at the opening so that the second sealing area faces the first sealing area, forming a seal portion between the first sealing area of ​​the exterior film and the second sealing area of ​​the lid body, which at least partially seals between the first sealing area and the second sealing area, impregnating at least a portion of the first sealing area and at least a portion of the second sealing area with a material in a fluid state, and solidifying the material in a fluid state to form a seal reinforcement portion that reinforces the seal portion.

[0015] A manufacturing method for an energy storage device according to a tenth aspect of the present invention includes preparing an electrode body, wrapping the electrode body in an exterior film having a first sealing area to form an opening, placing a lid body having a second sealing area at the opening so that the second sealing area faces the first sealing area, forming a seal portion between the first sealing area of ​​the exterior film and the second sealing area of ​​the lid body that at least partially seals the area between the first sealing area and the second sealing area, preparing a reinforcing member that is configured to be attached to the lid body and covers at least a portion of the first sealing area and at least a portion of the second sealing area from the outside of the lid body, and attaching the reinforcing member to the lid body to form a seal reinforcement portion that reinforces the seal portion. Effect of the Invention

[0016] According to the present invention, an electricity storage device is provided in which the sealing performance between the lid and the exterior film is improved. [Brief description of the drawings]

[0017] [Figure 1] 1 is a perspective view of an electricity accumulation device according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of the electrode body of FIG. [Diagram 3] 2 is a cross-sectional view showing a layer structure of an exterior film included in the electricity storage device of FIG. 1. [Figure 4] FIG. 4 is a perspective view showing a schematic configuration of an end portion of an exterior film. [Diagram 5] FIG. 4 is a perspective view showing a schematic configuration of a lid body. [Figure 6] FIG. 4 is a front view showing a schematic configuration around the lid body. [Figure 7A] 4 is a flowchart showing a method for manufacturing the electricity storage device according to the first embodiment. [Figure 7B] FIG. [Figure 8] FIG. 11 is a perspective view showing a schematic configuration of the periphery of a lid of an electricity storage device according to a second embodiment. [Figure 9] 13A to 13C are views for explaining a method of forming a seal reinforcement portion according to a second embodiment. [Figure 10] FIG. 11 is a perspective view showing a schematic configuration of the periphery of a lid of an electricity storage device according to a third embodiment. [Figure 11] FIG. 13 is a perspective view showing a schematic configuration of an electricity accumulation device according to a fourth embodiment. [Figure 12] FIG. 13 is a perspective view showing a schematic configuration of an electricity accumulation device according to a modified example. [Figure 13] FIG. 4 is a diagram showing an example of a usage state of the power storage device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an electric storage device according to an embodiment of the present invention will be described with reference to the drawings. In addition, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated. In addition, the drawings do not necessarily reflect the actual dimensions of each member. In this embodiment, a numerical range indicated by "~" means "more than or equal to" or "less than or equal to". For example, the notation "2 to 15 mm" means 2 mm or more and 15 mm or less. In the numerical ranges described in stages in this embodiment, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. In addition, the upper limit and upper limit, the upper limit and lower limit, or the lower limit and lower limit described separately may be combined to form a numerical range.

[0019] [1. First embodiment] <1-1. Configuration of the power storage device> Fig. 1 is a perspective view that typically illustrates an electricity storage device 10 of a first embodiment. The electricity storage device 10 includes an electrode body 20, a pair of electrode terminals 30, and an exterior body 40. In Fig. 1, the direction of arrows UD indicates the thickness direction of the electricity storage device 10, the direction of arrows 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 the same in the subsequent figures.

[0020] [Electrode body] FIG. 2 is a side view showing a schematic configuration of the electrode body 20. The electrode body 20 includes electrodes (positive and negative electrodes) constituting a storage member such as a lithium ion battery, a capacitor, an all-solid 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, and a separator. In this embodiment, the electrode body 20 has an approximately rectangular parallelepiped shape. Note that the term "approximately rectangular parallelepiped" includes, in addition to a complete rectangular parallelepiped, a solid that can be regarded as a rectangular parallelepiped by modifying the shape of a part of the outer surface, for example. However, the electrode body 20 may have a three-dimensional shape including multiple corners, such as an approximately polygonal prism, or may have an approximately cylindrical shape.

[0021] As shown in FIG. 2, in this embodiment, the electrode body 20 has a front surface 21, a rear surface 22, an upper surface 23, a lower surface 24, a first side surface 25, and a second side surface 26. However, the front surface 21, the rear surface 22, the first side surface 25, and the second side surface 26 are imaginary surfaces when the electrode body 20 is regarded as a substantially rectangular parallelepiped. The front surface 21 faces one of the lid bodies 60. The rear surface 22 faces the other lid body 60. The upper surface 23 constitutes one of the first surfaces 41 of the exterior body 40 described later. The lower surface 24 constitutes the other of the pair of first surfaces 41 of the exterior body 40 described later. The first side surface 25 constitutes one of the pair of second surfaces 42 of the exterior body 40 described later. The second side surface 26 constitutes the other of the pair of second surfaces 42 of the exterior body 40 described later. The electrode body 20 has ridge portions 20A, 20B, 20C, and 20D. Ridge portion 20A is formed at the boundary between upper surface 23 and first side surface 25. Ridge portion 20B is formed at the boundary between upper surface 23 and second side surface 26. Ridge portion 20C is formed at the boundary between first side surface 25 and lower surface 24. Ridge portion 20D is formed at the boundary between second side surface 26 and lower surface 24. In other words, a ridge portion refers to a boundary between two surfaces that intersect with each other. The ends of each of ridge portions 20A to 20D become corner portions 230 that correspond to the vertices of a substantially rectangular parallelepiped.

[0022] [Exterior body] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a pair of lid bodies 60. The exterior film 50 wraps the electrode body 20 so as to form a pair of openings 40A. In this embodiment, the exterior film 50 is wrapped around the electrode body 20 so as to form a pair of openings 40A. The exterior film 50 has a protruding portion 50X that protrudes outward from the portion wrapping the electrode body 20 when the exterior film 50 wraps the electrode body 20. The pair of lid bodies 60 are respectively disposed on the sides of the electrode body 20 so as to close the pair of openings 40A.

[0023] For example, there is a method of forming a storage portion (recess) for storing the electrode body 20 in the exterior film 50 through cold forming. However, it is not necessarily easy to form a deep storage portion by such a method. If an attempt is made to form a deep storage portion (recess) (for example, a forming depth of 15 mm) by cold forming, pinholes or cracks will occur in the exterior film 50, which is likely to lead to a decrease in battery performance. On the other hand, in this embodiment, the exterior body 40 seals the electrode body 20 by wrapping the exterior film 50 around the electrode body 20, so that the electrode body 20 can be easily sealed regardless of the thickness of the electrode body 20. Note that in order to reduce the dead space between the electrode body 20 and the exterior film 50 so as to improve the volumetric energy density of the electricity storage device 10 and to improve the cooling efficiency, it is preferable that the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20. Moreover, in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery to exert battery performance, and therefore it is necessary to eliminate the space between the electrode body 20 and the exterior film 50. Therefore, it is preferable that the exterior film 50 is wrapped around the electrode body 20 so as to be in contact with the outer surface of the electrode body 20.

[0024] [Exterior film] Fig. 3 is a cross-sectional view showing the layer structure of the exterior film 50. As shown in Fig. 3, the exterior film 50 is a laminate (laminate film) having, for example, a base layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in this order. Note that the exterior film 50 does not need to include all of these layers, and for example, the barrier layer 52 may not be included. That is, the exterior film 50 may be made of a material that is flexible and easily bendable, and may be made of, for example, a resin film. Note that the exterior film 50 is preferably heat-sealable.

[0025] The base layer 51 included in the exterior film 50 is a layer for imparting heat resistance to the exterior film 50 and suppressing the occurrence of pinholes that may occur during processing or distribution. The base layer 51 is configured to include at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, the base layer 51 includes at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer, so that the barrier layer 52 can be protected during processing of the exterior film 50 and breakage of the exterior film 50 can be suppressed. In addition, 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, in terms of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The base layer 51 may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the base layer 51 is, for example, preferably 5 to 300 μm, and more preferably 20 to 150 μm, from the viewpoint of film strength.

[0026] The barrier layer 52 is a layer that at least prevents the intrusion of moisture. 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 foil, vapor deposition film, and resin layer having barrier properties. Examples of the vapor deposition film include metal vapor deposition film, inorganic oxide vapor deposition film, and carbon-containing inorganic oxide vapor deposition film, and examples of the resin layer include fluorine-containing resins such as polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, and polymers mainly composed of fluoroalkyl units, and ethylene-vinyl alcohol copolymers. Examples of the barrier layer 52 include resin films having at least one of these vapor deposition films and resin layers. The barrier layer 52 may be provided in a plurality of layers. It is preferable that the barrier layer 52 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 material contains at least one of an aluminum alloy foil and a stainless steel foil.

[0027] In the barrier layer 52, the layer made of the above-mentioned metal material may contain recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, or steel plate. These recycled materials can be obtained by known methods. The recycled aluminum alloy material can be obtained by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 52 may be made of only recycled materials, or may be made of a mixed material of recycled materials and virgin materials. Note that recycled metal materials refer to metal materials that have been made reusable by collecting, isolating, and refining various products used in the city and waste from the manufacturing process. In addition, virgin metal materials refer to new metal materials refined from natural metal resources (raw materials) and are not recycled materials.

[0028] 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, the aluminum alloy foil is preferably an iron-containing aluminum alloy foil. 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 making the iron content 0.1% by mass or more, an exterior film 50 having better formability can be obtained. By making the iron content 9.0% by mass or less, an exterior film 50 having better flexibility can be obtained. Examples of the soft aluminum alloy foil 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, etc. may be added as necessary. Softening can be performed by annealing treatment, etc. From the viewpoint of improving the mechanical strength of the exterior film 50, it is more preferable that the aluminum alloy foil is a hard aluminum alloy foil composed of, for example, a work-hardened aluminum alloy. Examples of the hard aluminum alloy foil include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14.

[0029] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardened stainless steel foils. From the viewpoint of providing an exterior film 50 with excellent formability, the stainless steel foil is preferably made of austenitic stainless steel.

[0030] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferred.

[0031] In the case of a metal foil, the thickness of the barrier layer 52 should be such that it at least functions as a barrier layer to prevent the intrusion of moisture, and may be, for example, about 5 to 200 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. Preferable ranges for the thickness of the barrier layer 52 include about 9.0 to 85 μm, about 9.0 to 50 μm, about 9.0 to 40 μm, about 9.0 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 52 is made of an aluminum alloy foil, the above-mentioned ranges are particularly preferable. From the viewpoint of imparting high formability and high rigidity to the exterior film 50, the thickness of the barrier layer 52 is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and even more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, and even more preferably about 70 μm or less. Preferable ranges are about 35 to 200 μm, about 35 to 85 μm, about 35 to 75 μm, about 35 to 70 μm, about 45 to 200 μm, about 45 to 85 μm, about 45 to 75 μm, about 45 to 70 μm, about 50 to 200 μm, about 50 to 85 μm, about 50 to 75 μm, about 50 to 70 μm, about 55 to 200 μm, about 55 to 85 μm, about 55 to 75 μm, and about 55 to 70 μm. When the exterior film 50 has high formability, deep drawing becomes easy, which can contribute to increasing the capacity of the electricity storage device. Furthermore, when the capacity of the electricity storage device is increased, the weight of the electricity storage device increases, but the rigidity of the exterior film 50 is increased, which 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.

[0032] In addition, when the barrier layer 52 is a metal foil, it is preferable that at least the surface opposite to the base layer 51 is provided with a corrosion-resistant film in order to prevent dissolution and corrosion. The barrier layer 52 may be provided with a corrosion-resistant film on both sides. Here, the corrosion-resistant film refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) on the barrier layer 52 by performing, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment by applying a coating agent on the surface of the barrier layer 52. Specifically, the corrosion-resistant film refers to a film that improves the acid resistance of the barrier layer 52 (acid-resistant film), a film that improves the alkali resistance of the barrier layer 52 (alkali-resistant film), etc. The treatment for forming the corrosion-resistant film may be one type, or two or more types may be combined. In addition, not only one layer but also multiple layers may be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved by 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. In addition, when the barrier layer 52 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 52.

[0033] 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 moisture, and in particular 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.

[0034] The heat-sealable resin layer 53 is bonded to the barrier layer 52, for example, via an adhesive layer 55. The heat-sealable resin layer 53 included in the exterior film 50 is a layer that imparts heat-sealing sealability 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, cyclic polyolefin resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 300 μm, more preferably 40 to 150 μm, from the viewpoints of sealability and strength.

[0035] The exterior film 50 preferably has one or more layers having a buffer function (hereinafter referred to as "buffer layer") outside the heat-sealable resin layer 53, more preferably outside the barrier layer 52. The buffer layer may be laminated on the outside of the base material layer 51, or the base material layer 51 may also function as a buffer layer. When the exterior film 50 has multiple buffer layers, the multiple buffer layers may be adjacent to each other, or may be laminated via the base material layer 51, the barrier layer 52, etc.

[0036] The material constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. The material having cushioning properties is, for example, rubber, nonwoven fabric, or foam sheet. The rubber is, for example, natural rubber, fluororubber, or 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 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 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. Among these, the thickness of the buffer layer is most preferably in the range of 1000 μm to 3000 μm.

[0037] When the buffer layer is made of rubber, the lower limit of the thickness of the buffer layer is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the thickness of the buffer layer is preferably 10 mm, more preferably 5 mm, and more preferably 2 mm. When the buffer layer is made of rubber, the preferred range of the thickness of the buffer layer is 0.5 mm to 10 mm, 0.5 mm to 5 mm, or 0.5 mm to 2 mm.

[0038] 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 electricity storage device 10 is dropped or by handling during production of the electricity storage device 10.

[0039] In this embodiment, the first sealing portion 70 is formed by heat-sealing the surfaces (thermally adhesive resin layer 53) of the exterior film 50 facing each other in a state where the exterior film 50 is wrapped around the electrode body 20 and the lid body 60. In this embodiment, the first sealing portion 70 extends in the longitudinal direction (FB direction) of the exterior body 40. The position where the first sealing portion 70 is formed in the exterior body 40 can be arbitrarily selected. In this embodiment, the root 70X of the first sealing portion 70 is 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 root 70X of the first sealing portion 70 may be located on any surface of the exterior body 40. In this embodiment, the first sealing portion 70 is folded, for example, toward the second surface 42 of the exterior body 40. The first sealing portion 70 may protrude outward beyond the electrode body 20 in a plan view, or may be folded toward the first surface 41.

[0040] FIG. 4 is a perspective view showing a schematic configuration of an end portion in the FB direction of the exterior film 50. As shown in FIG. 4, the exterior film 50 has a first seal area 500. The first seal area 500 is a virtual area present in the peripheral portion of the opening 40A, and the heat-sealable resin located in the first seal area 500 is heat-sealed with a lid seal portion 63 of the lid body 60 described later to form a second seal portion 80. Preferably, the first seal area 500 includes a peripheral portion 5000 that defines the periphery of the opening 40A. The second seal portion 80 is an example of the seal portion of the present invention. Note that, although FIG. 4 shows only one end portion in the FB direction of the exterior film 50, the other end portion in the FB direction of the exterior film 50 also has the first seal area 500.

[0041] [Lid] 5 is a perspective view showing a schematic configuration of the lid body 60. The lid body 60 is a member arranged to close the opening 40A, and is, for example, a plate-like member having a polygonal shape when viewed from the FB direction of the electricity storage device 10. The lid body 60 is made of, for example, resin. The lid body 60 may be formed by, for example, cold forming the exterior film 50. Alternatively, the lid body 60 may be a metal molded product. Furthermore, the material constituting the lid body 60 may contain at least one or more materials selected from the group consisting of metal, metal oxide, carbon fiber reinforced plastic, and rubber.

[0042] The lid body 60 has a first surface 61, a second surface 62, and a lid seal portion 63. The first surface 61 faces the electrode body 20. The second surface 62 is the surface opposite to the first surface 61. The lid seal portion 63 is connected to the first surface 61 and the second surface 62, and is heat-sealed to the heat-fusible resin layer 53 of the exterior film 50 to form a second sealed portion 80. In other words, the lid seal portion 63 is an example of the second sealed region of the present invention.

[0043] The lid seal portion 63 includes a first seal surface 63A, a second seal surface 63B, a third seal surface 63C, and a fourth seal surface 63D. The first seal surface 63A constitutes the upper surface of the lid body 60. The first seal surface 63A extends in a first direction (LR direction in this embodiment) in a front view of the lid body 60. The second seal surface 63B and the third seal surface 63C are connected to the first seal surface 63A and constitute the side surface of the lid body 60. The second seal surface 63B and the third seal surface 63C extend in a second direction (UD direction in this embodiment) intersecting the first direction in a front view of the lid body 60. In this embodiment, the first direction and the second direction are orthogonal to each other in a front view of the lid body 60. The first direction and the second direction do not have to be orthogonal to each other in a front view of the lid body 60. The fourth seal surface 63D constitutes the lower surface of the lid body 60. The fourth sealing surface 63D extends in a first direction (the LR direction in this embodiment) when the lid 60 is viewed from the front.

[0044] When the lid body 60 is plate-shaped, it is preferable that the lid body 60 has a certain degree of thickness so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is arranged in a stacked manner. From another viewpoint, when the lid body 60 is plate-shaped, it is preferable that the lid seal portion 63 of the lid body 60 has a certain degree of thickness so that the lid seal portion 63 of the lid body 60 and the exterior film 50 can be suitably heat-sealed when the second sealing portion 80 is formed. The minimum value of the thickness of the lid body 60 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum value of the thickness of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 12 mm. The preferred ranges of the thickness of the material constituting the lid body 60 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 12 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 12 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 12 mm. In this embodiment, when the lid body 60 is expressed as a plate-like body, the embodiment in which the lid body 60 is composed only of a film defined by the [packaging terminology] standard of JIS (Japan Industrial Standards) is not included. The thickness of the lid body 60 may vary depending on the part of the lid body 60. When the thickness of the lid body 60 varies depending on the part, the thickness of the lid body 60 is the thickness of the thickest part.

[0045] The lid seal portion 63 further includes boundaries 64, 65, 66, and 67. The boundary 64 is a boundary between the first seal surface 63A and the second seal surface 63B. The boundary 65 is a boundary between the first seal surface 63A and the third seal surface 63C. The boundary 66 is a boundary between the fourth seal surface 63D and the second seal surface 63B. The boundary 67 is a boundary between the fourth seal surface 63D and the third seal surface 63C. That is, the boundaries 64 to 67 form the top of the lid body 60. The shapes of the boundaries 64 to 67 may be angular, or may be rounded by performing R processing. In this embodiment, the boundaries 64 to 67 are angular.

[0046] From the viewpoint of suitable heat sealing between the lid 60 and the exterior film 50, it is preferable that the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 of the exterior film 50 are mainly made of the same material. In this embodiment, the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 are mainly made of polypropylene. That is, the second sealing portion 80 according to this embodiment is formed with polypropylene as the main material. Note that the main material refers to a material that occupies 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 when the total material contained in the constituent elements is taken as 100% by mass.

[0047] In this embodiment, the lid body 60 is formed with a through hole 60X into which the electrode terminal 30 described later is inserted. The through hole 60X penetrates the first surface 61 and the second surface 62. When the electrode body 20 is stored, the electrode terminal 30 protrudes to the outside of the exterior body 40 through the through hole 60X formed in the lid body 60. A small gap between the through hole 60X of the lid body 60 and the electrode terminal 30 is filled with, for example, resin. In the electricity storage device 10, the position from which the electrode terminal 30 protrudes to the outside can be arbitrarily selected. For example, the electrode terminal 30 may protrude to the outside from a hole formed in any one of the six surfaces of the exterior body 40. In this case, a small gap between the exterior body 40 and the electrode terminal 30 is filled with, for example, resin. In the electricity storage device 10, the lid body 60 and the electrode terminal 30 are provided as separate bodies, but the lid body 60 and the electrode terminal 30 may be formed integrally. If the electrode terminals 30 do not protrude from the edge of the exterior body 40, the lid body 60 does not need to have the through-holes 60X formed therein.

[0048] [Electrode terminal] Referring again to FIG. 1, the power storage device 10 according to this embodiment includes a pair of electrode terminals 30. The electrode terminals 30 are metal terminals used for inputting and outputting electric power in the electrode body 20. One end of the electrode terminal 30 is electrically connected to the electrode body 20 (positive electrode or negative electrode). The other end of the electrode terminal 30 protrudes outward from an edge of the exterior body 40, for example. Note that the electrode terminal 30 may not protrude from the exterior body 40, for example, as long as it is capable of inputting and outputting electric power to and from the electrode body 20. When the cover body 60 described later is made of, for example, a metal, the cover body 60 may also function as the electrode terminal 30. In this case, the cover body 60 having the function as an electrode terminal may or may not protrude from the exterior body 40.

[0049] The metal material constituting the electrode terminal 30 is, for example, aluminum, nickel, copper, etc. For example, when the electrode body 20 is a lithium ion battery, the electrode terminal 30 connected to the positive electrode is usually made of aluminum, etc., and the electrode terminal 30 connected to the negative electrode is usually made of copper, nickel, etc.

[0050] [Seal reinforcement part] Fig. 6 is a front view showing the configuration around the lid body 60. As shown in Fig. 6, the electricity storage device 10 further includes one or more seal reinforcement parts 90. The seal reinforcement parts 90 are parts that reinforce the sealing by the second sealing part 80. In the example shown in Fig. 6, the seal reinforcement parts 90 are formed between the first sealing area 500 of the exterior film 50 and the lid seal part 63 (second sealing area) of the lid body 60, at least in a part where the second sealing part 80 is not formed. The part where the second sealing part 80 is not formed may be one place or two or more places.

[0051] The second sealing portion 80 is formed in a state where the lid seal portion 63 and the first sealing region 500 are faced to each other, and the entire lid seal portion 63 is wrapped in the exterior film 50. At this time, the length of the lid seal portion 63 (i.e., the length in the circumferential direction of the lid body 60) does not match the length of the exterior film 50 that wraps it, and a sagging portion may occur in the exterior film 50. In the example of FIG. 6, the sagging portions are the portions indicated by the reference characters 501 and 502. For convenience of explanation, the size of the sagging portions 501 and 502 is emphasized in FIG. 6, but the sagging portions 501 and 502 do not have to protrude from the surface of the exterior film 50 that forms the second sealing portion 80. In the sagging portions 501 and 502 of the exterior film 50, the heat-sealable resin of the lid seal portion 63 and the heat-sealable resin of the first sealing region 500 do not come into sufficient contact with each other, and an unsealed portion where the second sealing portion 80 is not formed is likely to occur. If such an unsealed portion is present, when the electrode body 20 contains an electrolyte, the electrolyte may leak out of the exterior body 40, or at least one of gas and moisture may penetrate into the interior of the exterior body 40, which may have an undesirable effect on the performance of the electricity storage device 10. The seal reinforcement portion 90 compensates for the unsealed portion that may cause a decrease in the performance of the electricity storage device 10, and improves the sealing property between the lid body 60 and the exterior film 50. Note that the unsealed portion is not necessarily limited to one caused by sagging of the exterior film 50, and may be one caused by other causes or one that is intentionally formed, for example, for the convenience of manufacturing.

[0052] In the example of FIG. 6, two seal reinforcement parts 90 are formed in the sagging parts 501 and 502 so as to fill the gap between the lid seal part 63 and the first seal area 500. The seal reinforcement part 90 formed in the sagging part 501 improves the seal between the lid body 60 and the exterior film 50 more effectively than the seal reinforcement part 90 formed in the sagging part 502. The sagging part 501 is located closer to the protruding part 50X (first sealing part 70). Since the protruding part 50X is movable with respect to the root 70X of the first sealing part 70, a larger load is applied to the second sealing part 80 near the root 70X compared to other parts. That is, there is a higher need to reinforce the seal by the second sealing part 80 near the root 70X. For this reason, it can be said that a seal reinforcement portion 90 formed closer to the root 70X is more effective in improving the sealing performance between the lid body 60 and the exterior film 50 compared to a seal reinforcement portion 90 formed further distal to the root 70X.

[0053] The seal reinforcement portion 90 is formed by a method described later. The material forming the seal reinforcement portion 90 includes, for example, at least one of resin, metal, ceramic, and rubber. The material also includes, for example, a mixture of at least two of resin, metal, ceramic, and rubber, and a composite of at least two of resin, metal, ceramic, and rubber. The composite includes, for example, a material in which different materials are bonded at a molecular level. The resin includes at least one of thermoplastic resin, photocurable resin, room temperature curable resin, thermosetting resin, and electron beam curable resin (hereinafter, these resins may be collectively referred to as "curable resin"). Examples of the thermoplastic resin include polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polyolefin resins such as polyethylene resin and polypropylene resin, cyclic polyolefin resin, and acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The photocurable resin is a resin that is cured by irradiation with light of a specific wavelength. Examples of photocurable resins include radical polymerization resins that undergo radicalization of a photopolymerization initiator when irradiated with ultraviolet light, and are cured by a radical chain reaction with the functional groups of a monomer or oligomer, and cationic polymerization resins that begin a cationic polymerization reaction when irradiated with ultraviolet light. Examples of radical polymerization resins include acrylic resins, and examples of cationic polymerization resins include epoxy resins and vinyl ether. Examples of room temperature curable resins include resins that are mainly made of epoxy resins, ester resins, or acrylic resins and are cured by mixing with a curing agent. Examples of thermosetting resins include phenol resins, epoxy resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, silicone resins, polyurethanes, and thermosetting polyimides. Examples of electron beam curable resins include acrylic resins.

[0054] <1-2. Manufacturing method of electricity storage device> 7A is a flowchart showing an example of a method for manufacturing the power storage device 10. The method for manufacturing the power storage device 10 according to the first embodiment will be described below. However, the order of performing the following steps S1 to S8 is not limited to the following order and can be changed as appropriate.

[0055] In step S1, each element of the electricity storage device 10 is prepared. Specifically, the electrode body 20, a pair of electrode terminals 30, an exterior film 50, and a pair of lid bodies 60 are prepared.

[0056] In step S2, each electrode terminal 30 is joined to the lid body 60. In this embodiment, each electrode terminal 30 is joined to the lid body 60 so as to protrude toward the second surface 62 through the through hole 60X. Here, a gap between the peripheral surface of the electrode terminal 30 and the inner wall surface of the through hole 60X of the lid body 60 may be filled with resin. Completion of step S2 results in the creation of a lid unit 600 (see FIG. 7B) in which the electrode terminal 30 is joined to the lid body 60.

[0057] In step S3, the lid unit 600 is placed so as to face the front surface 21 and rear surface 22 of the electrode body 20, and the electrode terminals 30 and the electrode body 20 are joined together.

[0058] Alternatively, the manufacturing method for the electricity storage device 10 may include, instead of steps S2 and S3, a step of first joining the electrode body 20 and the electrode terminal 30, and then joining the lid body 60 to the electrode terminal 30 joined to the electrode body 20. In this example, the electrode terminal 30 may protrude to the outside of the exterior body 40 from between any one of the sealing surfaces 63A-63D and the exterior film 50.

[0059] In step S4, the electrode body 20 is wrapped in the exterior film 50 so as to form a pair of openings 40A. The method for wrapping the electrode body 20 is not particularly limited, and for example, the exterior film 50 may be wrapped around the electrode body 20 and the lid body 60. At this time, the portion of the exterior film 50 located on the periphery of the opening 40A becomes the first sealed region 500. As a result, the first sealed region 500 faces the lid seal portions 63 of the pair of lid bodies 60.

[0060] In step S5, the facing heat-sealable resin layers 53 of the exterior film 50 are heat-sealed to form a first sealed portion 70 (hereinafter referred to as a "provisional first sealed portion") having a part that is unsealed. The unsealed portion can be formed, for example, by using a seal bar shaped so that a part of the seal bar does not come into contact with the exterior film 50. In another example, the unsealed portion can be formed by interposing a fluororesin film or the like between the mutually facing surfaces (heat-sealable resin layers 53) of the exterior film 50. By forming the provisional first sealed portion before the second sealed portion 80, the electrode body 20 can be held by the exterior film 50, so that the position of the electrode body 20 relative to the exterior film 50 is unlikely to shift. Therefore, the occurrence of wrinkles is suppressed when the second sealed portion 80 is formed.

[0061] In step S6, the second sealed portion 80 is formed. The second sealed portion 80 is formed by heat-sealing the heat-fusible resin layer 53 of the first sealed region 500 of the exterior film 50 and the lid seal portion 63 of the lid body 60. Note that step S6 may be performed before step S5.

[0062] In step S7, the seal reinforcement portion 90 is formed. More specifically, in step S6, a material for forming the seal reinforcement portion 90 is injected into a portion (unsealed portion of the second sealing portion 80) between the first sealing region 500 and the lid sealing portion 63 where the second sealing portion 80 has not been formed. The portion where the second sealing portion 80 has not been formed is identified, for example, by a leak test or the like. The injection of the material for forming the seal reinforcement portion 90 can be performed, for example, by injecting the material in a fluid state into the unsealed portion of the second sealing portion 80 with a nozzle or the like, and then solidifying the material. Alternatively, the material in a fluid state can be pressed into the unsealed portion of the second sealing portion 80 by pressure. As a result, the seal reinforcement portion 90 is formed in the unsealed portion of the second sealing portion 80.

[0063] In step S8, an electrolyte is injected through the unsealed portion of the temporary first sealed portion, and aging and degassing are performed. Note that, when the power storage device 10 is an all-solid-state battery, the step of injecting an electrolyte through the unsealed portion of the temporary first sealed portion is omitted.

[0064] In step S9, the exterior film 50 is evacuated as necessary, and then the unsealed portion of the temporary first sealed portion is heat sealed to form the first sealed portion .

[0065] <1-3. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10, even if the second sealing portion 80 is not formed between the exterior film 50 and the lid body 60 and an unsealed portion occurs in the second sealing portion 80, that portion is filled by the seal reinforcing portion 90. This makes it possible to more reliably seal the gap between the exterior film 50 and the lid body 60.

[0066] [2. Second embodiment] The electricity storage device 10A of the second embodiment differs from the first embodiment in the configuration and formation method of a seal reinforcement portion 90A, but the other configurations are similar to those of the first embodiment. The following describes the electricity storage device 10A of the second embodiment, focusing on the differences from the first embodiment.

[0067] <2-1. Configuration of the power storage device> FIG. 8 is a perspective view showing the configuration around the lid body 60 of the power storage device 10A of the second embodiment (however, the electrode terminal 30 is omitted). As shown in FIG. 8, in the power storage device 10A, the seal reinforcement part 90A (the shaded part in FIG. 8) covers the entire first seal area 500 and the second seal area (the lid seal part 63 of the lid body 60) from the outside of the exterior film 50, and further covers the entire second surface 62 of the lid body 60. Preferably, the seal reinforcement part 90A extends in the FB direction of the power storage device 10A and reaches the position where the corner part 230 of the electrode body 20 is present on the outer surface of the exterior film 50. That is, it is preferable that the seal reinforcement part 90A covers at least one of the multiple corner parts 230 of the electrode body 20 from the outside of the exterior film 50. Note that, although only the configuration around one of the lid bodies 60 is shown in FIG. 8, the configuration around the other lid body 60 is similar.

[0068] In the example shown in Fig. 8, the seal reinforcement part 90A is formed to a range that reaches a part of the overhang part 50X. In this way, when the seal reinforcement part 90A is formed to reach at least a part of the overhang part 50X, the seal reinforcement part 90A can also reinforce the overhang part 50X, particularly its base. However, the seal reinforcement part 90A may be formed excluding the overhang part 50X.

[0069] As a material for forming the seal reinforcement portion 90A, the same material as that for forming the seal reinforcement portion 90 can be used.

[0070] <2-2. Manufacturing method of electricity storage device> The manufacturing method of the electricity storage device 10A according to the second embodiment is different from the manufacturing method of the electricity storage device 10 in the method of forming the seal reinforcement part 90. That is, the manufacturing method of the electricity storage device 10A is different from the manufacturing method of the electricity storage device 10 in the specific content of step S7. This will be described below.

[0071] FIG. 9 is a diagram for explaining a method for forming the seal reinforcement portion 90A shown in FIG. 8. The container 990 shown in FIG. 9 is a container capable of housing the lid body 60 and its periphery, and can be, for example, a flexible container made of silicone resin. First, the lid body 60 and its periphery on one side of the power storage device 10A assembled in the process up to step S6 are housed in the container 990, and a material 91 (in a fluid state) for forming the seal reinforcement portion 90A is poured therein, and the lid body 60 including the entire first sealing region 500 and the entire second sealing region (lid seal portion 63) is impregnated with the material 91. Next, after the material 91 is solidified, the lid body 60 and the like are taken out of the container 990, and the excess material 91 is removed. According to this method, the first sealing region 500 and the lid seal portion 63, including the unsealed portion of the second sealing portion 80, are covered from the outside by the seal reinforcement portion 90A. By making the depth of the container 990 longer than the distance from the second surface 62 of the lid body 60 to the front surface 21 or back surface 22 of the electrode body 20 facing it, a seal reinforcement portion 90A can be formed so as to cover at least one of the corners 230 from the outside of the exterior film 50.

[0072] A slit (not shown) for the electrode terminal 30 to pass through may be formed in the bottom surface of the container 990. In this case, when the lid 60 and its periphery are housed in the container 990, the end of the electrode terminal 30 is caused to protrude from the slit to the outside of the bottom surface of the container 990, and the electrode terminal 30 is kept in close contact with the periphery of the slit, thereby preventing the electrode terminal 30 from being covered with the material 91.

[0073] <2-3. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10A of the second embodiment, even if the second sealing portion 80 is not formed between the exterior film 50 and the lid body 60 and an unsealed portion occurs, that portion is covered by the seal reinforcement portion 90A. This makes it possible to more reliably seal between the exterior film 50 and the lid body 60. Furthermore, when the seal reinforcement portion 90A reaches the protruding portion 50X, the protruding portion 50X can be reinforced. Furthermore, when the seal reinforcement portion 90A covers at least one of the corner portions 230 of the electrode body 20 from the outside of the exterior film 50, it is possible to prevent the corner portion 230 from breaking through the exterior film 50 and protruding.

[0074] When the seal reinforcement portion 90A extends on the outer surface of the exterior film 50 so as to cover at least one of the corners 230 of the electrode body 20, the seal reinforcement portion 90A can be formed of a material with relatively low stretching and deformability, thereby imparting an additional function to the seal reinforcement portion 90A that suppresses deformation of the exterior body 40. In the electricity storage device 10A, the internal pressure of the electricity storage device 10A may increase due to volume changes of the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charging and discharging, and gas generation, etc. When the internal pressure of the electricity storage device 10A increases, the exterior body 40 may expand. In addition, when vacuum drawing is performed in the manufacturing process of the electricity storage device 10B, the exterior body 40 may shrink. Since the seal reinforcement portion 90A extends on the outer surface of the exterior film 50 and reinforces the exterior film 50 at least in that portion, the above-mentioned deformation of the exterior body 40 can be limited.

[0075] [3. Third embodiment] The electricity storage device 10B of the third embodiment differs from the first embodiment in the configuration and formation method of a seal reinforcement portion 90B, but the other configurations are similar to those of the first embodiment. The following describes the electricity storage device 10B of the third embodiment, focusing on the differences from the first embodiment.

[0076] <3-1. Configuration of the power storage device> FIG. 10 is a perspective view showing the configuration around the lid body 60 of the electricity storage device 10B of the third embodiment (however, the electrode terminal 30 is omitted). As shown in FIG. 10, in the electricity storage device 10B, the seal reinforcement part 90B (the shaded part in FIG. 10) covers the entire first seal area 500 and the entire second seal area (the lid seal part 63 of the lid body 60) from the outside of the exterior film 50, and further covers the entire second surface 62 of the lid body 60. Preferably, the seal reinforcement part 90B extends in the FB direction of the electricity storage device 10B and reaches the position where the corner part 230 of the electrode body 20 is present on the outer surface of the exterior film 50. That is, it is preferable that the seal reinforcement part 90B covers at least one of the multiple corner parts 230 of the electrode body 20 from the outside of the exterior film 50. Note that, although only the configuration around one of the lid bodies 60 is shown in FIG. 10, the configuration around the other lid body 60 is similar.

[0077] Unlike the seal reinforcement part 90A, the seal reinforcement part 90B is formed by disposing a reinforcing member configured as a separate body from the exterior film 50 on the outside of the exterior film 50 and the lid body 60. The material forming the seal reinforcement part 90B may include, for example, resin, metal, rubber, metal oxide, a compound of metal oxide and resin, carbon fiber reinforced plastic, etc. When the electrode body 20 has an electrolyte, it is preferable that the seal reinforcement part 90B is formed including a material that does not allow the electrolyte to pass through or a material that is resistant to the electrolyte. In addition, it is preferable that the seal reinforcement part 90B is formed including a material that does not allow gas or moisture to pass through, or is formed including a layer that does not allow gas or moisture to pass through.

[0078] The shape and thickness of the seal reinforcement part 90B are not particularly limited. The seal reinforcement part 90B may be formed, for example, in a sheet shape. In this case, for example, a plurality of seal reinforcement parts 90B can be joined to the outside of the lid body 60 or the exterior film 50. The sheet-shaped seal reinforcement part 90B can be made of, for example, a resin film. The resin film may be a single-layer film or a multi-layer film. Also, for example, the seal reinforcement part 90B may be formed in a cap shape that can cover the end of the exterior body 40 from the outside of the lid body 60. The cap-shaped seal reinforcement part 90B can be made of, for example, rubber, a molded resin product, ceramics, metal, and a resin film (including a cold-formed product). In this way, the seal reinforcement part 90B may be made of one part as a whole, or may be made of two or more parts made of the same material or different materials. Furthermore, the thickness with which the seal reinforcement part 90B covers the exterior film 50 and the lid body 60 is not particularly limited.

[0079] The seal reinforcement portion 90B may or may not be bonded to the exterior body 40 (at least one of the lid body 60 and the exterior film 50). For example, when the seal reinforcement portion 90B includes an elastic material such as rubber and is formed in a cap shape, the seal reinforcement portion 90B can be attached to the end portion of the exterior body 40 by itself by utilizing the elasticity of the seal reinforcement portion 90B. On the other hand, when the seal reinforcement portion 90B is bonded to the exterior body 40, the bonding method is not particularly limited. Examples of the bonding method include a method of interposing an adhesive between the seal reinforcement portion 90B and the exterior body 40, a method of pouring the above-mentioned curable resin between the seal reinforcement portion 90B and the exterior body 40 and curing it, and a method of fusing the seal reinforcement portion 90B and the exterior body 40 with a heat-sealing resin. That is, the seal reinforcement portion 90B can be combined with the seal reinforcement portion 90 of the first embodiment or the seal reinforcement portion 90A of the second embodiment.

[0080] 10, the seal reinforcement portion 90B is formed in a portion excluding the overhang portion 50X. However, the seal reinforcement portion 90B may be formed to an extent that reaches at least a portion of the overhang portion 50X. In this way, when the seal reinforcement portion 90B is formed to reach at least a portion of the overhang portion 50X, the seal reinforcement portion 90B can also reinforce the overhang portion 50X, particularly its base.

[0081] <3-2. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10B of the third embodiment, even if the second sealing portion 80 is not formed between the exterior film 50 and the lid body 60 and an unsealed portion occurs, that portion is covered by the seal reinforcement portion 90B. This makes it possible to more reliably seal between the exterior film 50 and the lid body 60. Furthermore, when the seal reinforcement portion 90B reaches the protruding portion 50X, the protruding portion 50X can be reinforced. Furthermore, when the seal reinforcement portion 90B covers at least one of the corners 230 of the electrode body 20 from the outside of the exterior film 50, it is possible to prevent the corner 230 from breaking through the exterior film 50 and protruding.

[0082] In addition, by forming the seal reinforcement part 90B from a material with relatively low stretching deformation, the seal reinforcement part 90B can be given an additional function of suppressing deformation of the exterior body 40. In the electricity storage device 10B, the internal pressure of the electricity storage device 10B may increase due to volume changes of the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charging and discharging, and gas generation, etc. When the internal pressure of the electricity storage device 10B increases, the exterior body 40 may expand. However, since the seal reinforcement part 90B, which has relatively low stretching deformation, is present on the outside of the exterior film 50, the expansion of the exterior body 40 can be limited. In addition, when vacuum drawing is performed in the manufacturing process of the electricity storage device 10B, the exterior body 40 may shrink. When the seal reinforcement part 90B is at least partially joined to the exterior film 50, the seal reinforcement part 90B reinforces the exterior film 50 in that portion, so that the contraction of the exterior body 40 can be limited.

[0083] [4. Fourth embodiment] The electricity storage device 10C of the fourth embodiment is different from the third embodiment in that a seal reinforcement portion 90C covers at least one of the ridge portions 20A to 20D from the outside of the exterior body 40, but other configurations are similar to those of the third embodiment. The electricity storage device 10C of the fourth embodiment will be described below, focusing on the parts that differ from the third embodiment.

[0084] <4-1. Configuration of the power storage device> FIG. 11 is a perspective view showing a schematic configuration of an electricity storage device 10C (however, the electrode terminal 30 is omitted). As shown in FIG. 11, in the electricity storage device 10C, the seal reinforcement portion 90C has two end reinforcement portions 900C that cover both ends of the exterior body 40 in the FB direction. In addition to this, the electricity storage device 10C of the fourth embodiment further has four ridge reinforcement portions 901C that cover the ridge portions 20A to 20D of the electrode body 20 from the outside of the exterior body 40. That is, the end reinforcement portions 900C each cover the entire first seal area 500 and the second seal area (the lid seal portion 63 of the lid body 60) from the outside of the exterior film 50, and further cover the entire second surface 62 of the lid body 60. The ridge reinforcement portions 901C each cover at least a part of the ridge portions 20A to 20D of the electrode body 20 from the outside of the exterior body 40. In this embodiment, the ridge reinforcement portion 901C is connected to each of the two end reinforcement portions 900C. The materials constituting the two end reinforcement portions 900C and the ridge reinforcement portion 901C may be the same as those exemplified in the description of the seal reinforcement portion 90B of the third embodiment.

[0085] The ridge reinforcement portion 901C is preferably formed to be L-shaped as viewed from the FB direction so as to straddle the two faces forming the ridge portions 20A to 20D. However, in the portion of the overhang portion 50X, the ridge reinforcement portion 901C may be formed only on one face side of the overhang portion 50X. The ridge reinforcement portion 901C may be formed integrally with the both end reinforcement portions 900C, or may be formed as a separate body from the both end reinforcement portions 900C and joined to at least one of the outer surface of the exterior body 40 and the both end reinforcement portions 900C. For example, when the both end reinforcement portions 900C and the ridge reinforcement portion 901C are formed integrally with a flexible material, the exterior body 40 in a state in which the electrode body 20 is sealed is fitted into a space defined by the both end reinforcement portions 900C and the ridge reinforcement portion 901C, whereby the electricity storage device 10C including the seal reinforcement portion 90C can be manufactured. In addition, when the both end reinforcing parts 900C and the ridge reinforcement part 901C are formed as separate bodies, the both end reinforcing parts 900C and the ridge reinforcement part 901C may be combined in advance, and the exterior body 40 in a state in which the electrode body 20 is sealed may be fitted into a space defined by the both end reinforcing parts 900C and the ridge reinforcement part 901C. Alternatively, the both end reinforcing parts 900C and the ridge reinforcement part 901C may be attached to the exterior body 40, and then connected. The both end reinforcing parts 900C and the ridge reinforcement part 901C may be connected to each other by inserting a convex part formed on one side into a concave part formed on the other side, by fixing the two parts with an adhesive, or by fusing the two parts with a heat-sealing resin. Alternatively, the both end reinforcing parts 900C and the ridge reinforcement part 901C may simply be joined to the exterior body 40. The joining method to the exterior body 40 is as described in the second embodiment.

[0086] As in the second embodiment, preferably, the both-end reinforcing portions 900C extend in the FB direction of the electricity storage device 10B and reach a position on the outer surface of the exterior film 50 where the corners 230 of the electrode body 20 are located. That is, it is preferable that the both-end reinforcing portions 900C cover at least one of the multiple corners 230 of the electrode body 20 from the outside of the exterior film 50. However, the both-end reinforcing portions 900C may not reach a position where the corners 230 of the electrode body 20 are located, and the ridge line reinforcing portion 901C may cover at least one of the corners 230 of the electrode body 20 from the outside of the exterior film 50.

[0087] <4-2. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10C of the fourth embodiment, even if the second sealing portion 80 is not formed between the exterior film 50 and the lid body 60 and an unsealed portion occurs, that portion is covered by the both end reinforcing portions 900C. This makes it possible to more reliably seal between the exterior film 50 and the lid body 60. Furthermore, when at least one of the both end reinforcing portions 900C and the ridge line reinforcing portion 901C reaches the protruding portion 50X, the protruding portion 50X can be reinforced. Furthermore, when at least one of the both end reinforcing portions 900C and the ridge line reinforcing portion 901C covers at least one of the corner portions 230 of the electrode body 20 from the outside of the exterior film 50, it is possible to prevent the corner portion 230 from breaking through the exterior film 50 and protruding. Furthermore, since the ridge line reinforcing portion 901C covers from the outside of the exterior film 50 those portions of the ridge line portions 20A-20D of the electrode body 20 that are not covered by the both-end reinforcing portions 900C, it is possible to prevent the ridge line portions 20A-20D of the electrode body 20 from breaking through and protruding from the exterior film 50. Note that the ridge line reinforcing portion 901C does not have to be formed corresponding to all of the ridge lines of the ridge line portions 20A-20D, and the above-mentioned effect can be achieved even if only one ridge line reinforcing portion 901C is formed corresponding to any one of the ridge line portions.

[0088] Furthermore, when at least one of the end reinforcement parts 900C and the ridge reinforcement part 901C is formed of an elastic material, the seal reinforcement part 90C can deform in accordance with the expansion and contraction of the exterior body 40 that occurs during the manufacture and use of the electricity storage device 10C. More specifically, in the electricity storage device 10C, the internal pressure of the electricity storage device 10C may increase due to the volume change of the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charging and discharging, and the generation of gas. When the internal pressure of the electricity storage device 10C increases, the exterior body 40 may expand and the exterior film 50 may elongate. In addition, when vacuum drawing is performed in the manufacturing process of the electricity storage device 10C, the exterior film 50 may deform due to the contraction of the exterior body 40. If the seal reinforcement part 90C can follow such deformation of the exterior body 40, the seal reinforcement part 90C is less likely to separate from the exterior film 50. Therefore, the seal reinforcement part 90C can more reliably achieve the above-mentioned effect.

[0089] On the other hand, when the both end reinforcement portions 900C and the ridge line reinforcement portion 901C are formed of a material with relatively low stretching deformability, the seal reinforcement portion 90C has an additional effect of suppressing deformation of the exterior body 40. Specifically, the seal reinforcement portion 90C, which has relatively low stretching deformability, is present on the outside of the exterior film 50, thereby limiting the above-mentioned expansion of the exterior body 40. Furthermore, when the seal reinforcement portion 90C is at least partially joined to the exterior film 50, the seal reinforcement portion 90C reinforces the exterior film 50 in that portion, thereby limiting the above-mentioned contraction of the exterior body 40.

[0090] [5. Modifications] The above-mentioned embodiments are examples of possible forms of the electricity storage device and the manufacturing method of the electricity storage device according to the present invention, and are not intended to limit the forms. The electricity storage device and the manufacturing method of the electricity storage device according to the present invention may take forms different from those exemplified in the respective embodiments. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Some examples of modified forms of each embodiment are shown below. The above-mentioned embodiments and the following modified forms can be combined with each other as long as there is no technical contradiction.

[0091] (1) In the electricity storage device 10A of the second embodiment, the seal reinforcement part 90A does not have to cover the entire first seal area 500 and the entire lid seal part 63, and may at least partially cover the first seal area 500 and the lid seal part 63. More specifically, as long as the seal reinforcement part 90A covers a peripheral part 5000 (see FIG. 4) of the exterior film 50 that is the periphery of the opening 40A and a part of the lid seal part 63 that faces the peripheral part 5000, the effect of reinforcing the seal by the second sealing part 80 is achieved. In other words, the seal reinforcement part 90A does not have to cover the entire first seal area 500 and the entire lid seal part 63 in the FB direction of the electricity storage device 10. Furthermore, the seal reinforcement portion 90A may not cover the peripheral portion 5000 and the portion of the lid seal portion 63 facing the peripheral portion 5000 over the entire circumferential direction of the opening 40A. The same applies to the seal reinforcement portion 90B of the third embodiment and the seal reinforcement portion 90C of the fourth embodiment. Furthermore, in the power storage devices 10A to 10C of the second to fourth embodiments, the seal reinforcement portions 90A to 90C may not cover the entire second surface 62 of the lid body 60. That is, as long as the seal reinforcement portions 90A to 90C are formed so as to cover the boundary between the exterior film 50 (first seal region 500) and the lid body 60 (lid seal portion 63) in the FB direction, the seal reinforcement portions 90A to 90C may not be formed in the center of the lid body 60. Furthermore, the seal reinforcement portions 90A to 90C may simply be formed so as to cover at least one apex (boundary 64 to 67) of the lid body 60 and its periphery. This is because unsealed portions of the second sealing portion 80 are particularly likely to occur at the top of the lid body 60.

[0092] (2) The method for manufacturing the electricity storage device 10A of the second embodiment is not limited to that of the above embodiment. For example, in the step of forming the seal reinforcement portion 90A, the container 990 may be first filled with the material 91 in a fluid state, at least a part of the first seal region 500 and at least a part of the second seal region 500 may be impregnated with the filled material 91, and then the container 990 may be removed, and the material 91 may then be solidified.

[0093] (3) In the electricity storage device 10B of the third embodiment and the electricity storage device 10C of the fourth embodiment, the seal reinforcement portion 90B and the both end reinforcement portions 900C may further have a cushioning material for protecting the corner portion 230 of the electrode body 20. FIG. 12 is a diagram showing a configuration example of the cushioning material. In the example of FIG. 12, the cushioning material 92 is formed in an L-shape when viewed from the FB direction, and covers the corner portion 230 from the UD direction and the LR direction. The cushioning material 93 is formed in a plate shape when viewed from the UD direction, and is arranged, for example, on the upper surface of the protruding portion 50X (the surface on the first surface 41 side of the exterior body 40). The cushioning materials 92 and 93 are fixed to the outside of the seal reinforcement portion 90B or the both end reinforcement portions 900C, respectively, cover the corner portion 230 of the electrode body 20, and reduce impact applied to the exterior film 50 from the outside. For this reason, the cushioning materials 92 and 93 are preferably made of an elastic material such as rubber or elastomer.

[0094] In the above case, as already described, the seal reinforcement portion 90B and the both end reinforcement portions 900C may not reach the corner portion 230, and the cushioning material 92 or 93 may cover the corner portion 230. In addition to or instead of the form of FIG. 12, the cushioning material 92 may be fixed to the seal reinforcement portion 90B or the both end reinforcement portions 900C so as to be aligned with the lower surface of the protruding portion 50X and the second surface 42 of the exterior body 40. In addition to or instead of the form of FIG. 12, the cushioning material 93 may be fixed to the seal reinforcement portion 90B or the both end reinforcement portions 900C so as to be aligned with the lower surface of the protruding portion 50X. Furthermore, the cushioning material 92 or 93 may be fixed to the inside (part closer to the exterior film 50) of the seal reinforcement portion 90B or the both end reinforcement portions 900C, rather than to the outside.

[0095] (4) In the electricity storage devices 10, 10A to 10C of the first to fourth embodiments, the external shape of the exterior body 40 can be changed arbitrarily. For example, the lid body 60 does not have to be substantially rectangular when viewed from the FB direction of the electricity storage device 10, and may be another substantially polygonal shape, or may be a shape other than a substantially polygonal shape, such as a substantially circular shape or a substantially elliptical shape. The shape of the lid body 60 may be changed according to the three-dimensional shape of the electrode body 20, for example.

[0096] (5) In the electricity storage devices 10, 10A to 10C of the first to fourth embodiments, an adhesive film (not shown) may be bonded to the outer peripheral surface of the electrode terminal 30. Any adhesive film can be selected as long as it can bond the electrode terminal 30 made of metal and the lid body 60 made of, for example, resin. For example, the adhesive film can be a polyolefin resin such as a polyethylene resin or a polypropylene resin, a cyclic polyolefin resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The adhesive film can be a single layer or two or more layers of these films.

[0097] (6) In step S4 of the above manufacturing method, the exterior film 50 may be formed in advance as a cylindrical body having an opening 40A, and the electrode body 20 and the lid body 60 may be disposed inside the cylindrical body. This commonly applies to the electricity storage devices 10, 10A to 10C according to the first to fourth embodiments.

[0098] (7) An electricity storage device 10B including a cap-shaped reinforcing member of the third embodiment can be manufactured, for example, by modifying the manufacturing method of the electricity storage device 10 of the first embodiment as follows. In step S1, an electrode body 20, a pair of electrode terminals 30, an exterior film 50, a pair of lid bodies 60, and a pair of reinforcing members attachable to the lid bodies 60 are prepared. In step S8, each reinforcing member is attached to each lid body 60 to form a seal reinforcement portion 90B. Note that the preparation of the reinforcing members may be performed at a timing different from step S1, as long as it is performed before step S8.

[0099] (8) When the seal reinforcement parts 90A-90C of the second to fourth embodiments have a function of suppressing deformation of the exterior body 40 described above, the seal reinforcement parts 90A-90C may be configured to preferentially suppress deformation of a specific surface of the exterior body 4 depending on the manner in which the electricity storage devices 10A-10C are used. The electricity storage devices 10A-10C are used arranged in a row such that one of the second surfaces 42 of the multiple electricity storage devices 10A-10C (hereinafter, this will be referred to as the second surface 42B, and the other second surface 42 will be referred to as the second surface 42A) is in contact with the cooling mechanism 200, as shown in FIG. 13, the second surface 42B contacts the cooling mechanism 200, and the first surface 41A contacts the first surface 41B of the adjacent power storage devices 10A to 10C directly or indirectly via a plate-like member, a buffer material, or the like (one of the first surfaces 41 is referred to as the first surface 41A, and the other is referred to as the first surface 41B). For this reason, when considering expansion as one mode of deformation of the exterior body 40, for example, in the power storage devices 10A to 10C arranged as in FIG. 13, the first surface 41A, the first surface 41B, and the second surface 42B of the exterior body 40 are relatively unlikely to expand even if the internal pressure of the power storage devices 10A to 10C increases.

[0100] On the other hand, the second surface 42A of the exterior body 40 is not in contact with other elements such as the electricity storage devices 10A-10C, and is therefore prone to expansion when the internal pressure of the electricity storage devices 10A-10C increases. For this reason, the seal reinforcement parts 90A-90C can be arranged to extend over a wider area on the second surface 42A of the exterior body 40 and joined to the outer surface of the exterior film 50, for example, to suppress expansion of the second surface 42A. In this way, the seal reinforcement parts 90A-90C can be configured to suppress expansion of a specific surface of the exterior body 40. The above configuration applies not only to the expansion of the exterior body 40, but also to its contraction. [Explanation of symbols]

[0101] 10, 10A to 10C: Energy storage device 20: Electrode body 20A~D: Ridge 30: Electrode terminal 40: Exterior body 40A: Opening 50: Exterior film 60: Lid 63: Sealing surface (second sealing area) 64~67: Boundary (top) 80: Second sealing portion (seal portion) 90, 90A~90C: Seal reinforcement section 230: Corner 500: First seal area

Claims

1. An electrode body; an exterior film that wraps the electrode body to form an opening and has a first seal area; a cover disposed at the opening and having a second seal area facing the first seal area; a seal portion formed between the first seal area and the second seal area and at least partially sealing the gap between the first seal area and the second seal area; a seal reinforcing portion that reinforces sealing by the seal portion; Equipped with The seal reinforcement portion is formed between the first seal area and the second seal area, at least in a portion where the seal area is not formed. Energy storage device.

2. An electrode body, an exterior film that wraps the electrode body to form an opening and has a first seal area; a cover disposed at the opening and having a second seal area facing the first seal area; a seal portion formed between the first seal area and the second seal area and at least partially sealing the gap between the first seal area and the second seal area; a seal reinforcing portion that is formed separately from the exterior film and reinforces the sealing by the seal portion; Equipped with The lid body has a first surface facing the electrode body and a second surface opposite to the first surface, The seal reinforcement portion covers at least a portion of the first seal area, at least a portion of the second seal area, and at least a portion of the second surface from the outside of the exterior film and the lid body. Energy storage device.

3. An electrode body, an exterior film that wraps the electrode body to form an opening and has a first seal area; a cover disposed at the opening and having a second seal area facing the first seal area; a seal portion formed between the first seal area and the second seal area and at least partially sealing the gap between the first seal area and the second seal area; a seal reinforcing portion that reinforces sealing by the seal portion; Equipped with The electrode body has a three-dimensional shape including a plurality of corners, The seal reinforcement portion covers at least a part of the first seal area and at least a part of the second seal area from the outside of the exterior film and the lid body, and covers at least one corner of the plurality of corners from the outside of the exterior film. Energy storage device.

4. The material forming the seal reinforcement portion includes at least one of a resin, a metal, a ceramic, and a rubber, a mixture of at least two of them, and a composite of at least two of them. The electricity storage device according to claim 1 .

5. The lid body has a polygonal shape having an apex when viewed from the front, and the seal reinforcement part is formed so as to at least partially cover at least one apex of the polygonal shape of the lid body from the outside. The electricity storage device according to claim 2 or 3.

6. The electrode body has a three-dimensional shape including a plurality of corners, The seal reinforcement portion covers at least one of the plurality of corner portions from the outside of the exterior film. The power storage device according to claim 2 .

7. The electrode body has a three-dimensional shape including two surfaces intersecting each other and a ridge portion formed by the two surfaces, The seal reinforcement portion covers the ridge portion from the outside of the exterior film. The electricity storage device according to claim 3 or 6.

8. Providing an electrode body; wrapping the electrode assembly with an exterior film having a first seal area so as to form an opening; disposing a cover having a second sealing area on the opening such that the second sealing area faces the first sealing area; forming a seal portion between the first seal area of ​​the exterior film and the second seal area of ​​the lid body, at least partially sealing between the first seal area and the second seal area; forming a seal reinforcing portion for reinforcing the seal portion at least in a portion between the first seal area and the second seal area where the seal portion is not formed; Including, A method for manufacturing an electricity storage device.

9. Providing an electrode body; wrapping the electrode assembly with an exterior film having a first seal area so as to form an opening; a cover having a first surface, a second surface opposite to the first surface, and a second sealing area, is disposed in the opening such that the first surface faces the electrode body and the second sealing area faces the first sealing area; forming a seal portion between the first seal area of ​​the exterior film and the second seal area of ​​the lid body, at least partially sealing between the first seal area and the second seal area; impregnating at least a portion of the second surface, at least a portion of the first sealing area, and at least a portion of the second sealing area with a material in a flowable state; solidifying the fluidized material to form a seal reinforcement portion that reinforces the seal portion; Including, A method for manufacturing an electricity storage device.

10. Providing an electrode body; wrapping the electrode assembly with an exterior film having a first seal area so as to form an opening; a cover having a first surface, a second surface opposite to the first surface, and a second sealing area, is disposed in the opening such that the first surface faces the electrode body and the second sealing area faces the first sealing area; forming a seal portion between the first seal area of ​​the exterior film and the second seal area of ​​the lid body, at least partially sealing between the first seal area and the second seal area; preparing a reinforcing member that is configured to be attached to the lid and that covers at least a portion of the second surface, at least a portion of the first sealing area, and at least a portion of the second sealing area from an outside of the lid; attaching the reinforcing member to the lid to form a seal reinforcing portion that reinforces the seal portion; Including, A method for manufacturing an electricity storage device.

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