Power storage device, reinforcement part, and method for manufacturing power storage device

Abstract

To provide a power storage device that has high sealing properties, a reinforcement part that is used in the power storage device, and a method for manufacturing the power storage device.SOLUTION: A power storage device comprises: an electrode body; electrode terminals that are electrically connected to the electrode body; reinforcement parts that are arranged on lateral sides of the electrode body; and an exterior film that packs the electrode body and the reinforcement parts. The electrode terminal has an exposed part that is a part exposed to the outside on the opposite side of the electrode body with respect to the reinforcement part, the exposed part is partially joined to the exterior film.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electricity storage device, a reinforcing part used in an electricity storage device, and a method for manufacturing an electricity storage device. [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. [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 the above electricity storage device, there is a risk of a gap being formed between the lid and the electrode terminal penetrating the lid, which reduces the airtightness of the electricity storage device.

[0005] The present invention provides an electricity storage device with high sealing performance, a reinforcing part used in the electricity storage device, and a method for manufacturing the electricity storage device. [Means for solving the problem]

[0006] The energy storage device according to a first aspect of the present invention comprises an electrode body, an electrode terminal electrically connected to the electrode body, a reinforcing part arranged on the side of the electrode body, and an exterior film that packages the electrode body and the reinforcing part, wherein the electrode terminal has an exposed portion that is exposed to the outside on the opposite side of the electrode body from the reinforcing part, and a portion of the exposed portion is joined to the exterior film.

[0007] An electricity accumulation device according to a second aspect of the present invention is the electricity accumulation device according to the first aspect, wherein the reinforcing part includes at least a first part and a second part which are separated from each other.

[0008] An electricity accumulation device according to a third aspect of the present invention is the electricity accumulation device according to the first or second aspect, wherein the electrode body includes a current collector, and the reinforcing part has a recess in which the current collector is housed.

[0009] An electricity storage device according to a fourth aspect of the present invention is the electricity storage device according to the first or second aspect, wherein the electrode body includes a current collector, and the reinforcing part is a frame body having a space in which the current collector is disposed.

[0010] An electricity accumulation device according to a fifth aspect of the present invention is the electricity accumulation device according to any one of the first to third aspects, wherein the reinforcing part is plate-shaped and has a hole into which the electrode terminal is inserted.

[0011] An electricity storage device according to a sixth aspect of the present invention is the electricity storage device according to the first or second aspect, wherein the reinforcing part includes a main body portion and a movable portion connected to the main body portion and joined to the exterior film, and the movable portion is configured to move relative to the main body portion when the exterior film expands due to an increase in internal pressure of the electricity storage device.

[0012] An energy storage device according to a seventh aspect of the present invention is an energy storage device according to the first or second aspect, wherein the reinforcing part includes a first surface facing the electrode body and a second surface connected to the first surface and extending in a direction opposite to the electrode body, and the second surface inclines toward the center of the height of the reinforcing part as it extends in the direction opposite to the electrode body.

[0013] An energy storage device according to an eighth aspect of the present invention is an energy storage device according to the first or second aspect, wherein the reinforcing part includes a main body portion and an extension portion extending from the main body portion toward the electrode body, and the extension portion tapers toward the electrode body.

[0014] An energy storage device according to a ninth aspect of the present invention is an energy storage device according to any one of the first to eighth aspects, and includes a cushioning film that is arranged inside the exterior film and enhances the strength of the exterior film, and the cushioning film is arranged at least one of a corner of the electrode body and a corner of the reinforcing part.

[0015] An electricity storage device according to a tenth aspect of the present invention is an electricity storage device according to any one of the first to ninth aspects, wherein the electrode body and the reinforcing part are arranged at a distance from each other, and the exterior film has an expansion portion located in a portion between the electrode body and the reinforcing part, and the expansion portion is configured to be able to inflate when the exterior film expands in accordance with an increase in internal pressure of the electricity storage device.

[0016] An electricity storage device according to an eleventh aspect of the present invention comprises an electrode body, an electrode terminal electrically connected to the electrode body, a reinforcing part arranged on the side of the electrode body, and an exterior film that packages the electrode body and the reinforcing part, wherein the reinforcing part includes a main body portion and a movable part connected to the main body portion and joined to the exterior film, and the movable part is configured to move relative to the main body portion when the exterior film expands due to an increase in internal pressure of the electricity storage device.

[0017] An electricity storage device according to a twelfth aspect of the present invention comprises an electrode body, an electrode terminal electrically connected to the electrode body, a reinforcing part arranged on the side of the electrode body, and an exterior film for packaging the electrode body and the reinforcing part, wherein the reinforcing part includes a first surface facing the electrode body and a second surface connected to the first surface and extending in a direction opposite to the electrode body, and the second surface inclines toward the center of the height of the reinforcing part as it extends in the direction opposite to the electrode body.

[0018] An electricity storage device according to a thirteenth aspect of the present invention comprises an electrode body, an electrode terminal electrically connected to the electrode body, a reinforcing part arranged on the side of the electrode body, and an exterior film that packages the electrode body and the reinforcing part, wherein the reinforcing part includes a main body portion and an extension portion extending from the main body portion toward the electrode body, and the extension portion tapers toward the electrode body.

[0019] The energy storage device according to a fourteenth aspect of the present invention comprises an electrode body, an electrode terminal electrically connected to the electrode body, a reinforcing part arranged on the side of the electrode body, an exterior film for packaging the electrode body and the reinforcing part, and a cushioning film arranged inside the exterior film for increasing the strength of the exterior film, wherein the cushioning film is arranged at least one of a corner of the electrode body and a corner of the reinforcing part.

[0020] The electricity storage device according to a fifteenth aspect of the present invention comprises an electrode body, an electrode terminal electrically connected to the electrode body, a reinforcing part arranged on the side of the electrode body, and an exterior film packaging the electrode body and the reinforcing part, wherein the electrode body and the reinforcing part are arranged apart from each other, and the exterior film has an expansion portion located in a portion between the electrode body and the reinforcing part, and the expansion portion is configured to be able to inflate when the exterior film expands as the internal pressure of the electricity storage device increases.

[0021] An electricity accumulation device according to a sixteenth aspect of the present invention is the electricity accumulation device according to any one of the eleventh to fifteenth aspects, wherein the reinforcing part includes at least a first part and a second part which are separated from each other.

[0022] An electricity storage device according to a seventeenth aspect of the present invention is the electricity storage device according to any one of the eleventh to fifteenth aspects, wherein the electrode body includes a current collector, and the reinforcing part has a recess in which the current collector is housed.

[0023] An electricity accumulation device according to an eighteenth aspect of the present invention is the electricity accumulation device according to any one of the eleventh to fifteenth aspects, wherein the reinforcing part is plate-shaped and has a hole into which the electrode terminal is inserted.

[0024] A reinforcing part according to a nineteenth aspect of the present invention is used in the electricity accumulation device according to any one of the first to eighteenth aspects.

[0025] A reinforcing part according to a twentieth aspect of the present invention is the reinforcing part according to the nineteenth aspect, wherein the electrode terminal is joined to the reinforcing part.

[0026] A manufacturing method for an electricity storage device according to a twenty-first aspect of the present invention is a manufacturing method for an electricity storage device including an electrode body, an electrode terminal electrically connected to the electrode body, a reinforcing part arranged on a side of the electrode body, and an exterior film packaging the electrode body and the reinforcing part. The electrode terminal has an exposed portion that is a portion exposed to the outside on the opposite side of the electrode body from the reinforcing part, and a part of the exposed portion is joined to the exterior film. The manufacturing method for the electricity storage device includes a connecting step of electrically connecting the electrode body and the electrode terminal, an arranging step that is performed after the connecting step and that arranges the reinforcing part so that the exposed portion is formed, a packaging step that is performed after the arranging step and that packages the reinforcing part and the electrode body with the exterior film, and a sealing step that is performed after the packaging step and that joins the exterior film to the exposed portion.

[0027] A manufacturing method for an electricity storage device according to a 22nd aspect of the present invention is a manufacturing method for an electricity storage device according to the 21st aspect, wherein in the arrangement process, the reinforcing part is insert molded into the electrode terminal in a state connected to the electrode body. Effect of the Invention

[0028] According to the present invention, it is possible to provide an electricity storage device with high sealing performance, a reinforcing part used in the electricity storage device, and a method for manufacturing the electricity storage device. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a perspective view of an electricity storage device according to an embodiment. [Diagram 2] FIG. 2 is a plan view of the electricity storage device in FIG. 1. [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. 2 is a perspective view of a reinforcing part included in the electricity accumulation device in FIG. 1 . [Diagram 5] Cross-sectional view taken along line D5-D5 in Figure 2. [Figure 6] 4 is a flowchart showing an example of a method for manufacturing the electricity storage device in FIG. [Figure 7] FIG. 4 is a cross-sectional view of an electricity accumulation device according to a first modified example. [Figure 8] FIG. 11 is a cross-sectional view of an electricity accumulation device according to a second modified example. [Figure 9] FIG. 13 is a perspective view of a reinforcing part included in an electricity accumulation device according to a third modified example. [Figure 10] FIG. 13 is a cross-sectional view of an electricity accumulation device according to a third modified example. [Figure 11] 11 is a cross-sectional view of the power storage device in FIG. 10 in a state where the internal pressure of the exterior body is increased. [Figure 12] FIG. 13 is a perspective view of a reinforcing part included in an electricity accumulation device according to a fourth modified example. [Figure 13] FIG. 13 is a cross-sectional view of an electricity accumulation device according to a fourth modified example. [Figure 14] FIG. 13 is a perspective view of a reinforcing part included in an electricity accumulation device according to a fifth modified example. [Figure 15]FIG. 13 is a cross-sectional view of an electricity accumulation device according to a fifth modified example. [Figure 16] FIG. 13 is a cross-sectional view of an electricity accumulation device according to a sixth modified example. [Figure 17] FIG. 13 is a cross-sectional view of an electricity accumulation device according to a seventh modified example. [Figure 18] FIG. 13 is a cross-sectional view of an electricity accumulation device according to an eighth modified example. [Figure 19] FIG. 13 is a plan view of an electricity storage device according to another modified example of the embodiment. [Figure 20] FIG. 20 is a side view of the electricity storage device of FIG. [Figure 21] FIG. 13 is a plan view of an electricity storage device according to still another modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] 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 given the same reference numerals, and the description thereof will not be repeated. In this embodiment, a numerical range indicated by "~" means "more than or equal to" or "less than or equal to". For example, the notation of 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.

[0031] [1. Embodiment] <1-1. Configuration of the power storage device> FIG. 1 is a perspective view that shows a schematic diagram of an electricity storage device 10 according to an embodiment. FIG. 2 is a plan view of the electricity storage device 10 of FIG. 1. FIG. 3 is a cross-sectional view showing a layer structure of an exterior film 50 provided in the electricity storage device 10 of FIG. 1. FIG. 4 is a perspective view of a reinforcing part 60 provided in the electricity storage device 10 of FIG. 1. FIG. 5 is a cross-sectional view taken along line D5-D5 in FIG. 2. In FIGS. 2 and 5, the direction of arrow UD indicates the thickness direction of the electricity storage device 10, and the direction of arrow LR indicates the width direction of the electricity storage device 10. The direction of arrow FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UD, LR, and FB are common to the subsequent figures.

[0032] The electricity storage device 10 includes an electrode body 20, an electrode terminal 30, and an exterior body 40. The electrode body 20 includes electrodes (positive and negative electrodes) constituting an electricity storage member such as a lithium ion battery, a capacitor, or an all-solid-state battery, as well as a separator. In this embodiment, the shape of the electrode body 20 is a substantially rectangular parallelepiped. Note that the term "substantially rectangular parallelepiped" includes not only a perfect rectangular parallelepiped, but also a solid body that can be regarded as a rectangular parallelepiped by modifying the shape of a portion of the outer surface, for example. The shape of the electrode body 20 may be, for example, a cylinder or a polygonal prism.

[0033] In this embodiment, the electricity storage device 10 includes two electrode terminals 30. The electrode terminals 30 are metal terminals used for inputting and outputting electric power to and from the electrode body 20. One end of the electrode terminal 30 is connected to the current collector 20X, and is thereby electrically connected to an electrode (positive electrode or negative electrode) included in the electrode body 20. The other end of the electrode terminal 30 protrudes outward from an edge of the exterior body 40, for example.

[0034] The metal material constituting the electrode terminal 30 is, for example, aluminum, nickel, copper, etc. For example, when the electrode body 20 is a lithium ion battery, the electrode terminal 30 connected to the positive electrode is usually made of aluminum, etc., and the electrode terminal 30 connected to the negative electrode is usually made of copper, nickel, etc. The outermost layer of the electrode body 20 does not necessarily have to be an electrode, and may be, for example, a protective tape or a separator.

[0035] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a reinforcing part 60. The exterior film 50 packages the electrode body 20 and the reinforcing part 60 arranged on the side of the electrode body 20. In this embodiment, one exterior film 50 is wrapped around the electrode body 20 and the reinforcing part 60. The exterior film 50 is preferably wrapped around the electrode body 20 and the reinforcing part 60 along the MD (Machine Direction).

[0036] The electrode terminal 30 is joined to the reinforcing part 60 so as to have an exposed portion 30A, which is a portion exposed to the outside on the opposite side of the electrode body 20 with respect to the reinforcing part 60. From the viewpoint of suitably joining the electrode terminal 30 and the reinforcing part 60, it is preferable that an adhesive film 31 is joined to the electrode terminal 30. The adhesive film 31 can be arbitrarily selected as long as it is a film that can bond the electrode terminal 30 made of metal and the reinforcing part 60 made of resin. For example, the adhesive film 31 can be a polyolefin resin such as a polyethylene resin or a polypropylene resin, a cyclic polyolefin resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The adhesive film 31 can be a single layer or a film of two or more layers. A gas absorbent, a water absorbent, or the like may be added to the material constituting the adhesive film 31 as necessary. When a gas absorbent is added to the material constituting the adhesive film 31, it can absorb gas present in the electricity storage device 10 and attempting to leak out of the electricity storage device, and gas attempting to invade the electricity storage device 10 from the outside. When a water absorbing agent is added to the material constituting the adhesive film 31, it can absorb moisture present in the electricity storage device 10 and attempting to leak out of the electricity storage device, and moisture attempting to invade the electricity storage device 10 from the outside. As the water absorbing agent, a known water absorbing agent can be used, but an inorganic water absorbing agent can be suitably used. Specific examples of preferred inorganic water absorbing agents include calcium oxide, anhydrous magnesium sulfate, magnesium oxide, calcium chloride, zeolite, aluminum oxide, silica gel, alumina gel, and calcined alum. As the gas absorbing agent, a known gas absorbing agent can be used. For example, the gas absorbent may be hydrophobic zeolite with a SiO2 / Al2O3 molar ratio of 1 / 1 to 2000 / 1, bentonite, sepiolite, calcium oxide, copper oxide, zinc oxide, etc. In this embodiment, the adhesive film 31 is bonded to almost the entire portion of the electrode terminal 30 that is covered by the reinforcing part 60, and to a portion that is bonded to an exterior film 50 for forming a terminal sealing portion 90 described later.

[0037] 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, it is preferable that the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20. Furthermore, when the electricity storage device 10 is an all-solid-state battery, it is necessary to apply 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.

[0038] 3, the exterior film 50 is, for example, a laminate (laminate film) having 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 only needs to 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.

[0039] 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 5 to 150 μm, from the viewpoint of film strength.

[0040] 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.

[0041] 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.

[0042] From the viewpoint of improving the formability 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, the aluminum alloy foil containing iron is preferable. In the aluminum alloy foil containing iron (100 mass%), the content of iron is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%. By having an iron content of 0.1 mass% or more, an exterior film 50 having better formability can be obtained. By having an iron content of 9.0 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. If necessary, silicon, magnesium, copper, manganese, etc. may be added. Softening can be achieved by annealing or the like.

[0043] 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.

[0044] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferred.

[0045] In the case of a metal foil, the thickness of the barrier layer 52 is sufficient as long as it at least functions as a barrier layer that prevents moisture from penetrating, 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 10 μm or more, even more preferably about 20 μm or more, and more preferably about 25 μm or more. The preferred ranges of the thickness of the barrier layer 52 include about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 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 range is particularly preferable. From the viewpoint of imparting high formability and high rigidity to the exterior film 50, the thickness of the barrier layer 52 is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and even more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, and even more preferably about 70 μm or less. 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.

[0046] In addition, when the barrier layer 52 is an aluminum 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 such as 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] When the buffer layer is made of rubber, the lower limit of the buffer layer thickness is preferably 1 mm, more preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the buffer layer thickness is preferably 10 mm, more preferably 5 mm, more preferably 2 mm. When the buffer layer is made of rubber, the preferred ranges of the buffer layer thickness are 1 mm to 10 mm, 1 mm to 5 mm, 1 mm to 2 mm, 0.5 mm to 10 mm, 0.5 mm to 5 mm, and 0.5 mm to 2 mm.

[0052] 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.

[0053] 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 reinforcing part 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 selected arbitrarily. In this embodiment, the root 70X of the first sealing portion 70 is preferably located on the side 43 at the boundary between the first surface 41 and the second surface 42 of the exterior body 40. The first surface 41 has a larger area than the second surface 42. The 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.

[0054] The reinforcing part 60 is, for example, a rectangular parallelepiped shape as a whole, and is made of a resin material. The reinforcing part 60 is a lid that seals the side of the electrode body 20. Examples of materials constituting the reinforcing part 60 include polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, polyolefin resins such as polyethylene resins, fluorine resins, and polypropylene resins, cyclic polyolefin resins, and acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The material constituting the reinforcing part 60 can also be selected, for example, according to a specific example of the electricity storage device 10. When the electricity storage device 10 is a lithium ion secondary battery, the material constituting the reinforcing part 60 is preferably a material having electrolyte resistance or hydrofluoric acid resistance. When the electricity storage device 10 is an all-solid-state battery, the material constituting the reinforcing part 60 is preferably a material having hydrogen sulfide resistance. A gas absorbent, a water absorbent, and the like may be added to the material constituting the reinforcing part 60 as necessary. When a gas absorbent is added to the material constituting the reinforcing part 60, gas present in the electric storage device 10 and attempting to leak out of the electric storage device 10, and gas attempting to invade the electric storage device 10 from the outside can be absorbed. When a water absorbing agent is added to the material constituting the reinforcing part 60, moisture present in the electric storage device 10 and attempting to leak out of the electric storage device 10, and moisture attempting to invade the electric storage device 10 from the outside can be absorbed. As the water absorbing agent, a known water absorbing agent can be used, but an inorganic water absorbing agent can be suitably used. Specific examples of preferred inorganic water absorbing agents include calcium oxide, anhydrous magnesium sulfate, magnesium oxide, calcium chloride, zeolite, aluminum oxide, silica gel, alumina gel, and calcined alum. As the gas absorbing agent, a known gas absorbing agent can be used. For example, the gas absorbent may be hydrophobic zeolite having a SiO2 / Al2O3 molar ratio of 1 / 1 to 2000 / 1, bentonite, sepiolite, calcium oxide, copper oxide, or zinc oxide.

[0055] From the viewpoint of suitable heat sealing between the reinforcing part 60 and the exterior film 50, it is preferable that the main material of the material constituting the reinforcing part 60 is the same as the main material of the material constituting the heat-sealable resin layer 53 of the exterior film 50. In this embodiment, the main material of the material constituting the reinforcing part 60 and the main material of the material constituting the heat-sealable resin layer 53 is, for example, a polyolefin resin such as a polyethylene resin or a polypropylene resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The main material refers to, for example, a material that accounts for 50% or more of the materials contained in the components.

[0056] The reinforcing part 60 may be a metal molded part in addition to a resin molded part. When the reinforcing part 60 is a metal molded part, the material constituting the reinforcing part 60 may be, for example, an aluminum-based, titanium-based, nickel-based, copper-based, stainless steel-based, iron-based, or titanium-based material. When the reinforcing part 60 is a metal molded part or a resin molded part, it is preferable that the reinforcing part 60 has a certain degree of thickness so that the exterior body 40 is suppressed from being deformed even when the power storage device 10 is arranged in a stacked manner. From another perspective, when the reinforcing part 60 is a metal molded part or a resin molded part, it is preferable that the side surface 60C of the reinforcing part 60 has a certain degree of thickness so that the side surface 60C of the reinforcing part 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 reinforcing part 60 is, for example, 1.0 mm, more preferably 3 mm, and even more preferably 4 mm. The maximum value of the thickness of the reinforcing part 60 is, for example, 10 mm, more preferably 8.0 mm, and even more preferably 7.0 mm. The maximum value of the thickness of the reinforcing part 60 may be 10 mm or more. The preferred ranges of the thickness of the material constituting the reinforcing part 60 are 1.0 mm to 10 mm, 1.0 mm to 8.0 mm, 1.0 mm to 7.0 mm, 3.0 mm to 10 mm, 3.0 mm to 8.0 mm, 3.0 mm to 7.0 mm, 4.0 mm to 10 mm, 4.0 mm to 8.0 mm, and 4.0 mm to 7.0 mm. In the present disclosure, when the reinforcing part 60 is expressed as a metal molded product or a resin molded product, the film defined by the [Packaging Terminology] standard of JIS (Japan Industrial Standards) is not included as the material constituting the reinforcing part 60. The thickness of the reinforcing part 60 may vary depending on the part of the reinforcing part 60. When the thickness of the reinforcing part 60 varies depending on the part, the thickness of the reinforcing part 60 is the thickness of the thickest part. Note that these specifications regarding the reinforcing part 60 can be similarly applied to each of the following modified examples.

[0057] In this embodiment, from the viewpoint of suitably arranging the electrode terminal 30 at a desired position, the reinforcing part 60 has a first part 61 and a second part 62 that are divided. The first part 61 is arranged above the second part 62. The reinforcing part 60 may be configured to include three or more parts. When the reinforcing part 60 is configured by a plurality of divided parts, at least two parts may be configured by different materials. The first part 61 and the second part 62 are preferably bonded to the electrode terminal 30 by at least one selected from ultrasonic sealing, high frequency sealing, heat sealing, hot plate welding, infrared welding, and adhesive, via the adhesive film 31 as necessary. Since the electrode terminal 30 and the reinforcing part 60 are firmly bonded, the electrode terminal 30 can be suitably held by the reinforcing part 60. When the adhesive film 31 is not bonded to the electrode terminal 30, the first part 61 and the second part 62 are preferably bonded to the electrode terminal 30 by an adhesive. Examples of the adhesive include hot melt and adhesives used in dry lamination.

[0058] The shape of the first part 61 and the shape of the second part 62 can be selected arbitrarily as long as the electrode terminal 30 can be sandwiched between them so that power can be input and output via the electrode terminal 30. It is preferable that the first part 61 and the second part 62 have substantially the same shape. In this embodiment, the length of the first part 61 in the UD direction is longer than the length of the second part 62 in the UD direction. Therefore, the electrode terminal 30 is located below the center of the reinforcing part 60 in the UD direction. The electrode terminal 30 may be located at the center of the reinforcing part 60 or above the center in the UD direction.

[0059] As shown in FIG. 4, when the first part 61 and the second part 62 are combined, the reinforcing part 60 has a first surface 60A facing the electrode body 20, a second surface 60B opposite the first surface 60A, and a side surface 60C connecting the first surface 60A and the second surface 60B.

[0060] As shown in FIG. 5, in this embodiment, the exterior film 50 and the second surface 60B and the side surface 60C of the reinforcing part 60 are heat-sealed to form the second sealing portion 80. Furthermore, in this embodiment, the exterior film 50 and the exposed portion 30A of the electrode terminal 30 are joined to form a terminal sealing portion 90 in order to enhance the sealing property of the exterior body 40. In the terminal sealing portion 90, the exterior film 50 and the exposed portion 30A are joined via an adhesive film 31 as necessary. In this embodiment, it is sufficient that at least the terminal sealing portion 90 of the second sealing portion 80 and the terminal sealing portion 90 is formed. In other words, in this embodiment, the exterior film 50 and at least one of the second surface 60B and the side surface 60C of the reinforcing part 60 do not need to be joined.

[0061] <1-2. Manufacturing method of electricity storage device> 6 is a flowchart showing an example of a method for manufacturing the power storage device 10. The method for manufacturing the power storage device 10 includes, for example, a first step, a second step, a third step, a fourth step, a fifth step, a sixth step, a seventh step, an eighth step, and a ninth step. The first step to the ninth step are performed, for example, by a manufacturing apparatus for the power storage device 10. Note that in this embodiment, the first step to the ninth step are merely names of the steps defined for convenience, and do not refer to the order of the steps.

[0062] In a first process of step S11, the manufacturing device manufactures a first part 61 and a second part 62.

[0063] The second process of step S12 is performed after the first process. In the second process, the manufacturing device bonds the adhesive film 31 to the electrode terminal 30. Note that the second process may be performed before the first process.

[0064] The third step (connection step) of step S13 is performed after the second step. In the third step, the manufacturing apparatus electrically connects the electrode terminal 30 and the electrode of the electrode body 20 by connecting the electrode terminal 30 and the current collector 20X. Note that the third step may be performed before the second step.

[0065] The fourth step (arrangement step) of step S14 is performed after the first step, the second step, or the third step. In the fourth step, the manufacturing equipment sandwiches the electrode terminal 30 between the first part 61 and the second part 62. The manufacturing equipment bonds the first part 61 and the second part 62 to the electrode terminal 30 by at least one selected from ultrasonic sealing, high-frequency sealing, heat sealing, hot plate welding, infrared fusion, and an adhesive, for example. Completion of the fourth step results in bonding the electrode terminal 30 to the reinforcing part 60.

[0066] The fifth step (packaging step) of step S15 is performed after the fourth step. In the fifth step, the electrode body 20 and the reinforcing part 60 are packaged in an exterior film 50 in the manufacturing device.

[0067] The sixth step of step S16 is performed after the fifth step. In the fifth step, the manufacturing device heat-seals the opposing heat-sealable resin layers 53 of the exterior film 50 to form a first sealing portion 70 (hereinafter referred to as a "temporary first sealing portion") having an unsealed portion in a part thereof. The unsealed portion can be formed, for example, by using a seal bar having a shape such that a part of the seal bar does not contact 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 temporary first sealing portion before the second sealing portion 80 and the terminal sealing portion 90, 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, when the second sealing portion 80 and the terminal sealing portion 90 are formed, the occurrence of wrinkles is suppressed.

[0068] The seventh step of step S17 is performed after the sixth step. In the seventh step, the manufacturing apparatus forms the second sealed portion 80 by heat-sealing the exterior film 50 to the second surface 60B and the side surface 60C of the reinforcing part 60.

[0069] The eighth step (sealing step) of step S18 is performed after the seventh step. In the eighth step, the manufacturing apparatus forms the terminal sealing portion 90 by heat-sealing the exterior film 50 and the exposed portion 30A of the electrode terminal 30. Note that the eighth step may be performed before the seventh step.

[0070] The ninth step of step S19 is performed after the seventh step or the eighth step. In the ninth step, the manufacturing equipment injects an electrolyte solution from an unsealed portion of the temporary first sealed portion, evacuates the exterior film 50, and then heat-seals the unsealed portion to form the first sealed portion 70. When the power storage device 10 is an all-solid-state battery, the step of injecting the electrolyte solution in the ninth step is omitted.

[0071] <1-3. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10, since the terminal sealing portion 90 is provided, even if a gap exists between the electrode body 20 and the first part 61 and the second part 62 of the reinforcing part 60, the gap is closed by the exterior film 50. Therefore, the airtightness of the electricity storage device 10 is improved.

[0072] [2. First Modification of the Embodiment] An electricity storage device 210 according to a first modified example of the embodiment (hereinafter referred to as "first modified example") differs from the embodiment in that it includes a reinforcing part 260, but other configurations are similar to those of the embodiment. The following describes electricity storage device 210 according to the first modified example, focusing on the differences from the embodiment.

[0073] <2-1. Configuration of the power storage device> 7 is a cross-sectional view of an electricity storage device 210 of a first modified example. The electricity storage device 210 includes a reinforcing part 260. The reinforcing part 260 is a lid that seals the side of the electrode body 20. The reinforcing part 260 has a first part 261 and a second part 262 that are separated. The first part 261 is disposed above the second part 262. The reinforcing part 260 has a first surface 260A that faces the electrode body 20, a second surface 260B opposite to the first surface 260A, and a side surface 260C that connects the first surface 260A and the second surface 260B when the first part 261 and the second part 262 are combined.

[0074] In the first modification, from the viewpoint of shortening the distance between the reinforcing part 260 and the electrode body 20 in the FB direction, the reinforcing part 260 has a recess 260X that accommodates at least a part of the current collector 20X. In the first modification, the recess 260X has a size large enough to accommodate almost the entire current collector 20X. The recess 260X is recessed from the first surface 260A toward the second surface 260B. The recess 260X does not penetrate the first surface 260A and the second surface 260B. The depth LA of the recess 260X in the FB direction can be selected arbitrarily. From the viewpoint of accommodating more current collectors 20X, the additional depth LA is preferably half or more of the length of the side surface 260C in the FB direction.

[0075] <2-2. Actions and Effects of Electricity Storage Devices> The electricity storage device 210 of the first modification provides the same actions and effects as the electricity storage device 10 of the embodiment. Furthermore, according to the electricity storage device 210, since at least a part of the current collector 20X is housed in the recess 260X of the reinforcing part 260, the distance between the reinforcing part 260 and the electrode body 20 in the FB direction can be shortened. This allows the electricity storage device 210 to be configured compactly.

[0076] [3. Second Modification of the Embodiment] An electricity storage device 310 according to a second modified example of the embodiment (hereinafter referred to as "second modified example") differs from the embodiment in that it includes a reinforcing part 360, but other configurations are similar to those of the embodiment. The electricity storage device 310 according to the second modified example will be described below, focusing on the differences from the embodiment.

[0077] <3-1. Configuration of the power storage device> FIG. 8 is a cross-sectional view of an electricity storage device 310 of a second modified example. The electricity storage device 310 includes a reinforcing part 360. The reinforcing part 360 is a lid that seals the side of the electrode body 20. Depending on the shape of the reinforcing part 360, the exterior film 50 may be torn or wrinkled, which may prevent the electrode body 20 from being suitably sealed. The electricity storage device 310 of the second modified example is configured to be able to suitably seal the electrode body 20. The reinforcing part 360 includes a first part 361 and a second part 362 that are separated from each other. The first part 361 is disposed above the second part 362. When first part 361 and second part 362 are combined, reinforcing part 360 has a first surface 360A facing electrode body 20, a second surface 360B opposite first surface 360A, and a side surface 360C connecting first surface 360A and second surface 360B.

[0078] The second surface 360B is divided into a first inclined surface 360BX formed on the first part 361 and a second inclined surface 360BY formed on the second part 362. The first inclined surface 360BX and the second inclined surface 360BY extend in the direction opposite to the electrode body 20. The first inclined surface 360BX and the second inclined surface 360BY incline toward the center of the height direction (UD direction) of the reinforcing part 360 as they move in the direction opposite to the electrode body 20. In other words, the first inclined surface 360BX and the second inclined surface 360BY incline toward the electrode terminal 30 as they move in the direction opposite to the electrode body 20. Therefore, the first inclined surface 360BX and the second inclined surface 360BY approach each other as they move in the direction opposite to the electrode body 20. Since the area of ​​the second surface 360B is large, a large portion of the exterior film 50 is joined to the second surface 60B in the second sealing portion 80. This improves the hermetic sealing performance of the electricity storage device 310.

[0079] In the second modified example, the angle between the first inclined surface 360BX and the second inclined surface 360BY and the side surface 360C is more than 90 degrees from the viewpoint of preventing tearing of the exterior film 50 and preventing wrinkles from occurring in the exterior film 50 at the second sealing portion 80. Note that in the electricity storage device 310 of the second modified example, the terminal sealing portion 90 can be omitted.

[0080] <3-2. Actions and Effects of Electricity Storage Devices> According to the power storage device 310 of the second modification, the same action and effect as the power storage device 10 of the embodiment can be obtained. Furthermore, according to the power storage device 310, the angle between the first inclined surface 360BX and the second inclined surface 360BY and the side surface 360C is more than 90 degrees. Since the corner of the boundary between the side surface 360C and the second surface 360B is an obtuse angle, tearing of the exterior film 50 is suppressed. Furthermore, the occurrence of wrinkles in the exterior film 50 when the second sealing portion 80 is formed is suppressed.

[0081] [4. Third Modification of the Embodiment] An electricity storage device 410 according to a third modified example of the embodiment (hereinafter referred to as "third modified example") is different from the embodiment in that it includes a reinforcing part 460, but other configurations are similar to those of the embodiment. The following describes electricity storage device 410 according to the third modified example, focusing on the differences from the embodiment.

[0082] <4-1. Configuration of the power storage device> FIG. 9 is a perspective view of a reinforcing part 460 included in an electricity storage device 410 of a third modified example. FIG. 10 is a cross-sectional view of the electricity storage device 410. FIG. 11 is a cross-sectional view of the electricity storage device 410 of FIG. 10 in a state in which the internal pressure of the exterior body 40 has increased. When the electricity storage device 410 is used for a long time, the internal pressure of the exterior body 40 may increase due to at least one of gas generation and expansion of the electrode body 20. When the internal pressure of the exterior body 40 increases, the exterior film 50 may peel off from the reinforcing part 460. When the exterior film 50 peels off from the reinforcing part 460, the electrode body 20 cannot be suitably sealed. The electricity storage device 410 of the third modified example is configured to suitably seal the electrode body 20.

[0083] 9, reinforcing part 460 has a first part 461 and a second part 462 which are divided. Reinforcing part 460 is a cover that seals the side of electrode body 20. First part 461 is disposed above second part 462. Reinforcing part 460 has a first surface 460A facing electrode body 20, a second surface 460B opposite to first surface 460A, and a side surface 460C connecting first surface 460A and second surface 460B in a state where first part 461 and second part 462 are combined.

[0084] First part 461 has main body 461X and movable part 461Y movable relative to main body 461X. Second part 462 has main body 462X and movable part 462Y movable relative to main body 462X. Main body 461X, 462X constitute first surface 460A, second surface 460B, and side surface 460C.

[0085] The movable parts 461Y, 462Y move relative to the main body parts 461X, 462X when the exterior film 50 expands in accordance with the expansion of the electrode body 20. The movable part 461Y is connected to the main body part 461X only at the upper end part of the first surface 460A. The movable part 462Y is connected to the main body part 462X only at the lower end part of the first surface 460A. The main body parts 461X, 462X and the movable parts 461Y, 462Y may be integrally formed, or may be formed separately and joined together.

[0086] The shape of the movable parts 461Y, 462Y can be selected arbitrarily as long as it is a shape that can move with respect to the main body parts 461X, 462X. In the third modified example, the movable parts 461Y, 462Y are triangular prisms extending in the LR direction. In the LR direction, the relationship between the length of the movable parts 461Y, 462Y and the length of the main body parts 461X, 462X can be selected arbitrarily. In the third modified example, the length of the movable parts 461Y, 462Y and the length of the main body parts 461X, 462X are substantially equal in the LR direction. In the LR direction, the length of the movable parts 461Y, 462Y may be shorter than the length of the main body parts 461X, 462X. The movable parts 461Y, 462Y may be provided at least at one of the corners of the main body parts 461X, 462X of the first surface 460A.

[0087] An upper surface 461YX of the movable portion 461Y is joined, for example, by heat sealing to the exterior film 50. A lower surface 462YX of the movable portion 462Y is joined, for example, by heat sealing to the exterior film 50. In the electricity accumulation device 410 of the third modified example, the terminal sealing portion 90 can be omitted.

[0088] <4-2. Actions and Effects of Electricity Storage Devices> According to the power storage device 410 of the third modified example, in addition to the same actions and effects as those of the power storage device 10 of the embodiment, the following actions and effects can be obtained.

[0089] As shown in FIG. 11, when the power storage device 410 is used for a long time, the internal pressure of the exterior body 40 may increase due to at least one of the generation of gas and the expansion of the electrode body 20. In a typical example, the exterior body 40 and the electrode body 20 expand significantly in the UD direction. For example, the electrode body 20 expands, and the exterior film 50 is pushed by the electrode body 20. The upper surface 461YX of the movable part 461Y is joined to the exterior film 50. Therefore, as the internal pressure of the exterior body 40 increases, the movable part 461Y rotates with respect to the main body part 461X, with the upper end of the first surface 460A as the rotation center, so as to move away from the first surface 460A. The lower surface 462YX of the movable part 462Y is joined to the exterior film 50. Therefore, as the internal pressure of the exterior body 40 increases, the movable portion 462Y rotates with respect to the main body portion 462X about the lower end of the first surface 460A as the center of rotation so as to move away from the first surface 460A. According to the power storage device 410, even if the internal pressure of the exterior body 40 increases, peeling of the exterior film 50 from the reinforcing part 460 is suppressed.

[0090] [5. Fourth Modification of the Embodiment] An electricity storage device 510 according to a fourth modified example of the embodiment (hereinafter referred to as "fourth modified example") is different from the embodiment in that it includes a reinforcing part 560, but other configurations are similar to those of the embodiment. The following describes electricity storage device 510 according to the fourth modified example, focusing on the differences from the embodiment.

[0091] <5-1. Configuration of the power storage device> Fig. 12 is a perspective view of a reinforcing part 560 included in an electricity accumulation device 510 of a fourth modified example. Fig. 13 is a cross-sectional view of the electricity accumulation device 510.

[0092] As shown in FIG. 12, the reinforcing part 560 is, for example, plate-shaped and has a first surface 560A facing the electrode body 20, a second surface 560B opposite the first surface 560A, and a side surface 560C connecting the first surface 560A and the second surface 560B.

[0093] A hole 560X penetrating the first surface 560A and the second surface 560B is formed in the center of the reinforcing part 560. The size of the hole 560X is slightly larger than the electrode terminal 30. In the fourth modified example, in a fourth step (see FIG. 6) of the manufacturing method of the electricity storage device 510, the electrode terminal 30 connected to the electrode body 20 is inserted into the hole 560X of the reinforcing part 560. In the fourth modified example, when a gap occurs between the adhesive film 31 and the hole 560X, the gap is preferably filled with a resin material such as hot melt. Note that in the electricity storage device 510 of the fourth modified example, the terminal sealing portion 90 can also be omitted.

[0094] According to the power storage device 510 of the fourth modification, the same action and effect as the power storage device 10 of the embodiment can be obtained. Furthermore, according to the power storage device 510, the reinforcing part 560 is not divided, and therefore the strength of the reinforcing part 560 is high. Therefore, even if stress acts on the reinforcing part 560 due to vibration or the like, damage to the reinforcing part 560 is suppressed.

[0095] [6. Fifth Modification of the Embodiment] An electricity accumulation device 610 according to a fifth modified example of the embodiment (hereinafter referred to as "fifth modified example") is different from the embodiment in that it includes a reinforcing part 660, but other configurations are similar to those of the embodiment. The following describes electricity accumulation device 610 according to the fifth modified example, focusing on the differences from the embodiment.

[0096] <6-1. Configuration of the power storage device> Fig. 14 is a perspective view of a reinforcing part 660 included in an electricity accumulation device 610 of a fifth modified example. Fig. 15 is a cross-sectional view of the electricity accumulation device 610.

[0097] As shown in FIG. 14, reinforcing part 660 is a frame body having a first surface 660A facing electrode body 20, a second surface 660B opposite to first surface 660A, and a side surface 660C connecting first surface 660A and second surface 660B.

[0098] A hole 660X penetrating the first surface 660A and the second surface 660B is formed in the center of the reinforcing part 660. The size of the hole 660X is sufficiently large with respect to the electrode terminal 30. Inside the hole 660X, a space 660Y is formed in which at least a portion of the current collector 20X is disposed. In the fifth modified example, substantially the entire current collector 20X is disposed in the space 660Y.

[0099] In the fifth modification, in a fourth step (see FIG. 6) of the manufacturing method for the electricity storage device 610, the electrode terminal 30 connected to the electrode body 20 is inserted into the hole 660X of the reinforcing part 660. In the fifth modification, the hole 660X is sufficiently large compared to the electrode terminal 30, so that the reinforcing part 660 and the electrode terminal 30 are not joined in the fourth step. For this reason, in a second step (see FIG. 6) of the manufacturing method for the electricity storage device 610, it is preferable that the adhesive film 31 is joined only to a portion of the electrode terminal 30 that is joined to the exterior film 50. Note that in the electricity storage device 610 of the fifth modification, the terminal sealing portion 90 can be omitted.

[0100] <6-2. Actions and Effects of Electricity Storage Devices> The electricity storage device 610 of the fifth modified example provides the same actions and effects as the electricity storage device 10 of the embodiment. Furthermore, according to the electricity storage device 610, since at least a part of the current collector 20X is housed in the space 660Y of the reinforcing part 660, the distance between the reinforcing part 660 and the electrode body 20 in the FB direction can be shortened. This allows the electricity storage device 610 to be configured to be compact.

[0101] [7. Sixth Modification of the Embodiment] An electricity accumulation device 710 according to a sixth modified example of the embodiment (hereinafter referred to as "sixth modified example") is different from the embodiment in that it includes a reinforcing part 760, but other configurations are similar to those of the embodiment. The following describes electricity accumulation device 710 according to the sixth modified example, focusing on the differences from the embodiment.

[0102] <7-1. Configuration of the power storage device> FIG. 16 is a cross-sectional view of an electricity storage device 710 of a sixth modified example. The reinforcing part 760 has a first part 761 and a second part 762 that are separated. The reinforcing part 760 is a lid that seals the side of the electrode body 20. Depending on the shape of the reinforcing part 760, stress may be concentrated at the interface between the reinforcing part 760 and the electrode body 20, causing the exterior film 50 to be damaged. If the exterior film 50 is damaged, the electrode body 20 cannot be suitably sealed. The electricity storage device 710 of the sixth modified example is configured so that the electrode body 20 can be suitably sealed. The first part 761 is disposed above the second part 762. When the first part 761 and the second part 762 are combined, the reinforcing part 760 has a first surface 760A facing the electrode body 20, a second surface 760B opposite the first surface 760A, and a side surface 760C connecting the first surface 760A and the second surface 760B.

[0103] The first part 761 has a main body portion 761X and an extension portion 761Y extending from the main body portion 761X toward the electrode body 20. The second part 762 has a main body portion 762X and an extension portion 762Y extending from the main body portion 762X toward the electrode body 20. The main bodies 761X, 762X constitute a first surface 760A, a second surface 760B, and a side surface 760C. The main bodies 761X, 762X and the extension portions 761Y, 762Y may be integrally formed, or may be formed separately and joined together.

[0104] The extension portion 761Y extends from a portion including the upper end of the first surface 760A toward the electrode body 20. The extension portion 761Y has a shape that tapers toward the electrode body 20. The upper surface 761YX of the extension portion 761Y is preferably joined to the exterior film 50, for example, by heat heel. Since a wider range of the reinforcing part 760 is joined to the exterior film 50, the reinforcing part 760 and the exterior film 50 are more firmly joined. The upper surface 761YX does not have to be joined to the exterior film 50. The tip of the extension portion 761Y covers a part of the electrode body 20.

[0105] The extension portion 762Y extends from a portion including the lower end of the first surface 760A toward the electrode body 20. The extension portion 762Y has a tapered shape toward the electrode body 20. The lower surface 762YX of the extension portion 762Y is preferably joined to the exterior film 50, for example, by heat heel. Since a wider range of the reinforcing part 760 is joined to the exterior film 50, the reinforcing part 760 and the exterior film 50 are more firmly joined. The lower surface 762YX does not have to be joined to the exterior film 50. The tip of the extension portion 762Y covers a part of the electrode body 20.

[0106] In the LR direction, the relationship between the length of the extension portions 761Y, 762Y and the length of the main body portions 761X, 762X can be selected arbitrarily. In the sixth modified example, the length of the extension portions 761Y, 762Y and the length of the main body portions 761X, 762X are substantially equal in the LR direction. In the LR direction, the length of the extension portions 761Y, 762Y may be shorter than the length of the main body portions 761X, 762X. Note that in the power storage device 710 of the sixth modified example, the terminal sealing portion 90 may be omitted.

[0107] <7-2. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 710 of the sixth modification, the same actions and effects as those of the electricity storage device 10 of the embodiment can be obtained. Furthermore, according to the electricity storage device 710, the extensions 761Y, 762Y are tapered toward the electrode body 20, and therefore, stress is prevented from concentrating on the interface between the reinforcing part 760 and the electrode body 20. Therefore, damage to the exterior film 50 is prevented.

[0108] [8. Seventh Modification of the Embodiment] An electricity storage device 810 according to a seventh modified example of the embodiment (hereinafter referred to as "seventh modified example") differs from the embodiment in that it includes a buffer film 820, but other configurations are similar to those of the embodiment. The following describes electricity storage device 810 according to the seventh modified example, focusing on the differences from the embodiment.

[0109] <8-1. Configuration of the power storage device> FIG. 17 is a cross-sectional view of an electricity storage device 810 of a seventh modified example. When the strength of the exterior film 50 is low, there is a risk of pinholes occurring in the exterior film 50. When pinholes occur in the exterior film 50, the electrode body 20 cannot be suitably sealed. The electricity storage device 810 of the seventh modified example is configured to suitably seal the electrode body 20. The electricity storage device 810 has a buffer film 820 for increasing the strength of the exterior film 50. The buffer film 820 is disposed inside the exterior film 50. In order to suppress pinholes from occurring in the exterior film 50, the buffer film 820 is disposed at least one of the corners of the electrode body 20 and the corners of the reinforcing part 60. In the seventh modified example, the buffer film 820 is disposed at all corners of the electrode body 20 and all corners of the reinforcing part 60. The material constituting the buffer film 820 is, for example, a polyester-based material, a polyolefin-based material, or a fluorine-based material. In the electricity accumulation device 810 of the seventh modification, the terminal sealing portion 90 may be omitted.

[0110] <8-2. Actions and Effects of Electricity Storage Devices> The electricity storage device 810 of the seventh modification provides the same effects and advantages as the electricity storage device 10 of the embodiment. Furthermore, the electricity storage device 810 has the buffer film 820, which increases the strength of the exterior film 50. This reduces the risk of pinholes being formed in the exterior film 50.

[0111] [9. Eighth Modification of the Embodiment] An electricity storage device 910 according to an eighth modified example of the embodiment (hereinafter referred to as "eighth modified example") is different from the embodiment in that it includes an exterior film 950, but other configurations are similar to those of the embodiment. The following describes the electricity storage device 910 according to the eighth modified example, focusing on the differences from the embodiment.

[0112] <9-1. Configuration of the power storage device> FIG. 18 is a cross-sectional view of an electricity storage device 910 of an eighth modified example. The electricity storage device 910 includes an exterior film 950. When the internal pressure of the exterior body 40 increases, the exterior film 950 may peel off from the reinforcing part 60. When the exterior film 950 peels off from the reinforcing part 60, the electrode body 20 cannot be suitably sealed. The electricity storage device 910 of the eighth modified example is configured to suitably seal the electrode body 20. The exterior film 950 has an expansion portion 951 located between the electrode body 20 and the reinforcing part 60. The expansion portion 951 is configured to be able to expand when the exterior body 40 expands as the internal pressure of the exterior body 40 increases. The shape of the expansion portion 951 can be selected arbitrarily as long as it is an expandable shape. In the eighth modified example, the expansion portion 951 is a curved shape recessed toward the electrode terminal 30. The expansion portion 951 may be a corner recessed toward the electrode terminal 30, or may be a bellows shape. The expansion portion 951 does not need to be recessed, and may be a portion that is bent to an extent that it can expand. In the electricity accumulation device 910 of the eighth modified example, the terminal sealing portion 90 may be omitted.

[0113] <9-2. Actions and Effects of Electricity Storage Devices> The electricity storage device 910 of the eighth modification provides the same action and effect as the electricity storage device 10 of the embodiment. Furthermore, according to the electricity storage device 910, since the exterior film 50 has the expansion portion 951, peeling of the exterior film 950 from the reinforcing part 60 is suppressed even when the internal pressure of the exterior body 40 increases.

[0114] [10. Other Modifications] The above embodiment and each modification are examples of possible forms of the electricity storage device, reinforcing parts, and manufacturing method of the electricity storage device according to the present invention, and are not intended to limit the forms. The electricity storage device, reinforcing parts, and manufacturing method of the electricity storage device according to the present invention may take forms different from those exemplified in the embodiment and each modification. One example is a form in which a part of the configuration of the embodiment and each modification is replaced, changed, or omitted, or a form in which a new configuration is added to the embodiment and each modification. Below, several examples of other modifications of the embodiment and each modification are shown. Note that the above embodiment and each modification, as well as the following other modifications, can be combined with each other as long as there is no technical contradiction.

[0115] <10-1> In the electricity storage device 10 of the embodiment, the reinforcing part 60 does not have to be divided into the first part 61 and the second part 62. In this modification, in the manufacturing method of the electricity storage device 10 shown in FIG. 6, the first step may be omitted, and in the fourth step, the reinforcing part 60 may be insert molded into the electrode terminal 30 in a state connected to the electrode body 20. Note that in the fourth step, it is preferable to place a heat insulating material for protecting the electrode body 20 between the electrode body 20 and the portion where the reinforcing part 60 is formed. It is preferable to remove the heat insulating material after the fourth step. This modification can be similarly applied to the fourth modification.

[0116] <10-2> In the electricity storage device 10 of the embodiment, one of the two electrode terminals 30 does not have to be joined to the exterior film 50. In other words, one of the two electrode terminals 30 does not have to have a terminal sealing portion 90. For example, the one of the two electrode terminals 30 that does not have the terminal sealing portion 90 may have the second sealing portion 80 formed thereon. In other words, it is sufficient for the electricity storage device 10 to have at least one terminal sealing portion 90. Note that, in the first to eighth modified examples, the two terminal sealing portions 90 may be omitted.

[0117] <10-3> In the electricity storage device 10 of the embodiment, the two electrode terminals 30 may protrude from one of the two reinforcing parts 60. In this modification, the portion of the exterior body 40 where the other reinforcing part 60 is arranged can be sealed by a known method. For example, the portion where the other reinforcing part 60 is arranged may be sealed with a known reinforcing part constituted by one part, or the other reinforcing part 60 may be omitted and the electrode body 20 may be sealed by folding the exterior film 50. This modification can be similarly applied to the first to eighth modifications.

[0118] <10-4> In the electric storage device 10 of the embodiment, the exterior film 50 may be a laminate (laminate film) having a thermally adhesive resin layer 53 on both sides of the barrier layer 52. In this modification, the first sealing portion 70 may be formed by heat-sealing the thermally adhesive resin layers 53 laminated on one side or the other side of the barrier layer 52 to each other, or may be formed by heat-sealing the thermally adhesive resin layer 53 laminated on one side of the barrier layer 52 and the thermally adhesive resin layer 53 laminated on the other side of the barrier layer 52. In this modification, the base 70X of the first sealing portion 70 is located on any surface of the exterior body 40. In this modification, the base 70X of the first sealing portion 70 is preferably located in the vicinity of the side 43 at the boundary between the first surface 41 and the second surface 42. In this modification, the thermally adhesive resin layer 53 may be bonded to the barrier layer 52 via, for example, an adhesive layer 55. This modification can be similarly applied to the first modification to the eighth modification.

[0119] <10-5> In the electricity storage device 10 of the embodiment, the external shape of the exterior body 40 can be changed arbitrarily. Fig. 19 is a plan view of the electricity storage device 10 of a modified example. Fig. 20 is a side view of the electricity storage device 10 of Fig. 19.

[0120] In the electricity storage device 10 of this modified example, the exterior film 50 is wrapped around the electrode body 20 so as to have a protruding portion 70Y that protrudes outward beyond the electrode body 20. With the exterior film 50 wrapped around the electrode body 20 so as to have the protruding portion 70Y, the surfaces (thermally adhesive resin layer 53) of the exterior film 50 that face each other are heat sealed together to form a sealed portion 60Y. In this modified example, the protruding portion 70Y includes a first protruding portion 71Y and a second protruding portion 72Y. The electrode body 20 and the reinforcing part 60 are located between the first protruding portion 71Y and the second protruding portion 72Y.

[0121] The first overhanging portion 71Y faces the second overhanging portion 72Y via the electrode body 20 and the reinforcing part 60. The first overhanging portion 71Y has a pair of side portions 71A, 71B in the short-side direction of the exterior body 40 in a plan view. The second overhanging portion 72Y has a pair of side portions 72A, 72B in the short-side direction of the exterior body 40 in a plan view. In this modification, the side portions 71A, 71B, 72A, 72B are folded inward so that the heat-sealable resin layers (inner surfaces) of the exterior film 50 face each other. In other words, the side portions 71A, 71B, 72A, 72B are folded inward so that the base material layers 51 (outer surfaces) of the exterior film 50 face each other. In this modification, the exterior body 40 is a so-called Gabeltop type pouch.

[0122] The seal portion 60Y includes a first overhang seal portion 91Y and a second overhang seal portion 92Y. The first overhang seal portion 91Y is formed on the first overhang portion 71Y. The first overhang seal portion 91Y extends in the short direction of the exterior body 40. The first overhang seal portion 91Y includes a pair of side seal portions 91YA and a central seal portion 91YB. The pair of side seal portions 91YA are portions where the heat-fusible resin layers 53 of the pair of folded side portions 71A, 71B are heat-sealed to each other. The central seal portion 91YB is a portion located between the pair of side seal portions 91YA. The central seal portion 91YB is sealed with the electrode terminal 30 sandwiched therebetween. The portion of the exterior film 50 where the first overhang portion 71Y and the electrode terminal 30 are joined constitutes the terminal sealing portion 90.

[0123] The second overhang seal portion 92Y is formed in the second overhang portion 72Y. The second overhang seal portion 92Y extends in the short direction of the exterior body 40. The second overhang seal portion 92Y includes a pair of side seal portions 92YA and a central seal portion 92YB. The pair of side seal portions 92YA are portions where the heat-fusible resin layers of the pair of folded side portions 72A, 72B are heat-sealed to each other. The central seal portion 92YB is a portion located between the pair of side seal portions 92YA. The central seal portion 92YB is sealed with the two electrode terminals 30 sandwiched between them. The portion of the exterior film 50 where the second overhang portion 72Y and the electrode terminals 30 are joined constitutes the terminal sealing portion 90.

[0124] Fig. 21 is a plan view of an electricity storage device 10 according to another modified example of the embodiment. The power storage device 10 has a protruding portion 270Y. The protruding portion 270Y includes a first protruding portion 271Y and a second protruding portion 272Y that face each other via the electrode body 20 and the reinforcing part 60. The first protruding portion 271Y has a pair of side portions 271A, 271B in the short-side direction of the exterior body 40 in a plan view. The second protruding portion 272Y has a pair of side portions 272A, 272B in the short-side direction of the exterior body 40 in a plan view. In this modification, unlike the modification shown in FIG. 19 and the like, the exterior film 50 is not folded inwardly for the side portions 271A, 271B, 272A, 272B so that the inner surfaces of the exterior film 50 face each other. The width XA of the protruding portion 270 in the unfolded state is wider than the width XB of the electrode body 20. In this modification, the exterior body 40 is a so-called brick-shaped pouch.

[0125] The overhang seal portion 290Y includes a first overhang seal portion 291Y and a second overhang seal portion 292Y. The first overhang seal portion 291Y is formed in the first overhang portion 271Y. The first overhang seal portion 291 extends in the short direction of the exterior body 40. The first overhang seal portion 291Y includes a pair of side seal portions 291A and a central seal portion 291B. The pair of side seal portions 291A are portions in which the heat-sealable resin layers 53 of the exterior film 50 located outside the ends of the electrode body 20 in the width direction are heat-sealed to each other. The central seal portion 291B is a portion located between the pair of side seal portions 291A. The central seal portion 291B is sealed with the electrode terminal 30 sandwiched therebetween. The portion of the exterior film 50 in which the first overhang portion 271Y and the electrode terminal 30 are joined constitutes the terminal sealing portion 90.

[0126] The second overhang seal portion 292Y is formed in the second overhang portion 272Y. The second overhang seal portion 292Y extends in the short direction of the exterior body 40. The second overhang seal portion 292Y includes a pair of side seal portions 292A and a central seal portion 292B. The pair of side seal portions 292A are portions of the exterior film 50 located outside the ends of the electrode body 20 in the width direction, where the heat-fusible resin layers 53 are heat-sealed to each other. The central seal portion 292B is a portion located between the pair of side seal portions 292A. The central seal portion 292B is sealed with the two electrode terminals 30 sandwiched between them. The portion of the exterior film 50 where the second overhang portion 272Y and the electrode terminals 30 are joined constitutes the terminal sealing portion 90. The modified examples related to FIGS. 19 to 21 can be similarly applied to the first modified example to the eighth modified example.

[0127] <10-6> In the electricity storage device 10 of the embodiment, the electrode body 20 and the reinforcing part 60 are packaged by wrapping one exterior film 50 around them, but they may be packaged by joining two or more exterior films 50. This modification can be similarly applied to the first to eighth modifications.

[0128] <10-7> In the electricity storage device 10 of the embodiment, in order to more suitably bond the reinforcing part 60 and the exterior film 50, the reinforcing part 60 and the exterior film 50 may be bonded via an adhesive film. The specifications of the adhesive film in this modification are the same as those of the adhesive film 31. In particular, when the material constituting the reinforcing part 60 contains metal, it is preferable that the reinforcing part 60 and the exterior film 50 are bonded via an adhesive film. This modification can be similarly applied to the first modification to the eighth modification.

[0129] <10-8> In the electricity storage device 10 of the embodiment, the reinforcing part 60 is made of a resin material, but the reinforcing part 60 may be made of another material. The reinforcing part 60 may be made of, for example, ceramic or glass. Examples of ceramics include alumina-based, zirconia-based, silicon carbide-based, forsterite-based, silicon nitride-based, steatite, cordierite, sialon, ferrite, barium titanate, and mullite. [Explanation of symbols]

[0130] 10, 210, 310, 410, 510, 610, 710, 810, 910: Energy storage devices 20: Electrode body 20X: Current collector 30: Electrode terminal 30A:Exposed part 50, 950: Exterior film 60, 260, 360, 460, 560, 660, 760: Reinforcement parts 61, 261, 361, 461, 761: 1st part 62, 262, 362, 462, 762: 2nd part 260X: Recess 360B: 2nd side 461X, 462X: Main unit 461Y, 462Y: Movable part 560X, 660X: Hole 660Y: Space 761X, 762X: Main body 761Y, 762Y: Extension part 820: Cushioning film 951: Expansion section

Claims

1. Electrode body and The electrode body has an electrode terminal that is electrically connected to the electrode body, A reinforcing part positioned to the side of the electrode body, The electrode body and the reinforcing part are enclosed in an outer film, The aforementioned reinforcing parts are The main body and It includes an extended portion extending from the main body toward the electrode body, The extended portion tapers towards the electrode body, at least in the thickness direction of the electrode body. Energy storage device.

2. An electrode body, The electrode body has an electrode terminal that is electrically connected to the electrode body, A reinforcing part positioned to the side of the electrode body, The electrode body and the reinforcing part are enclosed in an outer film, The aforementioned reinforcing parts are The frame is the main body, It includes at least four extensions extending from the main body toward the electrode body, At least one of the extended portions tapers towards the electrode body. Energy storage device.

3. In a side view of the electrode body, the extended portion tapers in the width direction perpendicular to the thickness direction. The energy storage device according to claim 1.

4. The main body portion is The first surface facing the electrode body, Having a second surface opposite to the first surface, The extended portion extends toward the electrode body from the portion including the upper end of the first surface in the thickness direction of the electrode body. The energy storage device according to claim 1 or 2.

5. The main body portion is The first surface facing the electrode body, Having a second surface opposite to the first surface, The extended portion extends toward the electrode body from the portion including the lower end of the first surface in the thickness direction of the electrode body. The energy storage device according to claim 1 or 2.

6. The main body portion is The first surface facing the electrode body, Having a second surface opposite to the first surface, In a side view of the electrode body, the extended portion extends toward the electrode body from the end in the width direction perpendicular to the thickness direction of the electrode body. The energy storage device according to claim 1 or 2.

7. The extended portion has an inclined surface at its tip. The energy storage device according to claim 1 or 2.

8. The tip of the extended portion covers a part of the electrode body. The energy storage device according to claim 1 or 2.

9. The main body and the extension portion are integrally formed The energy storage device according to claim 1 or 2.

10. The main body and the extension are configured as separate parts. The energy storage device according to claim 1 or 2.

11. Having an adhesive film that joins the reinforcing part and the exterior film. The energy storage device according to claim 1 or 2.

12. The material constituting the reinforcing part includes at least one of aluminum-based, titanium-based, nickel-based, copper-based, stainless steel-based, iron-based, resin, ceramic, and glass. The energy storage device according to claim 1 or 2.

13. The reinforcing part includes at least a divided first part and a second part. The energy storage device according to claim 1 or 2.

14. The electrode body includes a current collector, The reinforcing part has a recess in which the current collector is housed. The energy storage device according to claim 1 or 2.

15. The reinforcing part is plate-shaped and has a hole into which the electrode terminal is inserted. The energy storage device according to claim 1 or 2.

16. A reinforcing part used in the energy storage device according to claim 1 or 2.

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