Power storage device and protective member for the same

Abstract

To provide a power storage device having improved durability.SOLUTION: A power storage device includes an electrode body having a three-dimensional shape including a ridge line, an exterior film covering at least one of the ridge lines and encasing the electrode body, and a protective member arranged on the outside of the electrode body along at least one of the ridge lines.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electricity storage device and a protective member for the 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 all-solid-state battery laminate, an electrode terminal, and an exterior body that seals the all-solid-state battery laminate. The exterior body includes a film strip member that is wrapped around the all-solid-state battery laminate to have an opening, and a lid body that is placed on the opening. The electrode terminal is electrically connected to the all-solid-state battery laminate. [Prior art documents] [Patent documents]

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

[0004] In an electricity storage device such as that of Patent Document 1, a film strip is wound around the side including the ridges of the all-solid-state battery laminate. However, such a film strip is easily damaged at the corners and ridges of the three-dimensional shape of the all-solid-state battery laminate, reducing the durability of the electricity storage device. This is not limited to all-solid-state battery laminates, but applies generally to cases where an electrode body having a three-dimensional shape including corners and ridges is wrapped with an exterior film. Patent Document 1 does not take this point into consideration.

[0005] An object of the present invention is to provide an electricity storage device with improved durability. [Means for solving the problem]

[0006] The energy storage device according to a first aspect of the present invention comprises an electrode body having a three-dimensional shape including a ridge portion, an exterior film covering at least one of the ridge portions and encasing the electrode body, and a protective member arranged on the outside of the electrode body along at least one of the ridge portions.

[0007] An electricity storage device according to a second aspect of the present invention is the electricity storage device according to the first aspect, wherein the protective member is disposed on the outer side of the exterior film.

[0008] An electricity storage device according to a third aspect of the present invention is the electricity storage device according to the first or second aspect, wherein the protective member is disposed inside the exterior film.

[0009] An electricity storage device according to a fourth aspect of the present invention is the electricity storage device according to any one of the first to third aspects, wherein the exterior film encases the electrode body so as to have an opening, and the electricity storage device further includes a lid body arranged in the opening.

[0010] A protective member according to a sixth aspect of the present invention is a protective member for an electricity storage device, the electricity storage device comprising an electrode body having a three-dimensional shape including ridges, and an exterior film that covers at least one of the ridges and encases the electrode body. The protective member is disposed on the outside of the electrode body along at least one of the ridges. Effect of the Invention

[0011] According to the present invention, an electricity storage device with improved durability is provided. [Brief description of the drawings]

[0012] [Figure 1] 1 is a perspective view of an electricity accumulation device according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view of the electrode body of FIG. [Diagram 3] 2 is a cross-sectional view showing a layer structure of an exterior film included in the electricity storage device of FIG. 1. [Figure 4] FIG. 4 is a perspective view showing a schematic configuration of a lid body. [Diagram 5] FIG. 4 is a perspective view showing a schematic configuration of a protective member. [Figure 6] FIG. 11 is a perspective view of an electricity accumulation device according to a second embodiment. [Figure 7] FIG. 11 is a perspective view showing a partial configuration of a protection member according to a second embodiment. [Figure 8] FIG. 11 is a perspective view of an electricity accumulation device according to a third embodiment. [Figure 9] FIG. 11 is a perspective view of a protection member and an electrode body according to a third embodiment. [Figure 10] FIG. 13 is a perspective view of a protection member and an electrode body according to a fourth embodiment. [Figure 11] FIG. 4 is a diagram showing an example of a usage state of the power storage device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, with reference to the drawings, a description will be given of an electric storage device according to some embodiments of the present invention. In addition, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description will not be repeated. In addition, the drawings do not necessarily reflect the actual dimensions of each member. In this embodiment, a numerical range indicated by "~" means "not less than" or "not more than". For example, the notation "2 to 15 mm" means 2 mm or more and 15 mm or less. In the numerical ranges described in stages in this embodiment, the upper limit or lower limit described in a certain numerical range may be replaced with the upper limit or lower limit of another numerical range described in stages. In addition, the upper limit and upper limit, the upper limit and lower limit, or the lower limit and lower limit described separately may be combined to form a numerical range.

[0014] [1. First embodiment] <1-1. Configuration of the power storage device> Fig. 1 is a perspective view that typically illustrates an electricity storage device 10 of a first embodiment. The electricity storage device 10 includes an electrode body 20, a pair of electrode terminals 30, an exterior body 40, and protective members 90, 91. In Fig. 1, the direction of arrow UD indicates the thickness direction of the electricity storage device 10, the direction of arrow LR indicates the width direction of the electricity storage device 10, and the direction of arrow FB indicates the depth direction of the electricity storage device 10. The directions indicated by the arrows UD, LR, and FB are the same in the subsequent figures.

[0015] [Electrode body] FIG. 2 is a side view showing a schematic configuration of the electrode body 20. The electrode body 20 includes electrodes (positive and negative electrodes) constituting a storage member such as a lithium ion battery, a capacitor, an all-solid battery, a semi-solid battery, a quasi-solid battery, a polymer battery, an all-resin battery, a lead-acid battery, a nickel-metal hydride battery, a nickel-cadmium battery, a nickel-iron battery, a nickel-zinc battery, a silver oxide-zinc battery, a metal-air battery, a polyvalent cation battery, or a capacitor, and a separator. In this embodiment, the electrode body 20 has an approximately rectangular parallelepiped shape. Note that the term "approximately rectangular parallelepiped" includes, in addition to a complete rectangular parallelepiped, a solid that can be regarded as a rectangular parallelepiped by modifying the shape of a part of the outer surface, for example. However, the electrode body 20 may have a three-dimensional shape including multiple corners, such as an approximately polygonal prism, or may have an approximately cylindrical shape.

[0016] As shown in FIG. 2, in this embodiment, the electrode body 20 has a front surface 21, a rear surface 22, an upper surface 23, a lower surface 24, a first side surface 25, and a second side surface 26. The upper surface 23 and the lower surface 24 correspond to the upper surface and the lower surface in the laminated structure of the electrode body 20, respectively. The front surface 21, the rear surface 22, the first side surface 25, and the second side surface 26 are imaginary surfaces when the electrode body 20 is regarded as a substantially rectangular parallelepiped, based on the upper surface 23 and the lower surface 24. The front surface 21 faces one of the lid bodies 60. The rear surface 22 faces the other lid body 60. In this embodiment, the upper surface 23 constitutes a first surface 41 of the exterior body 40 described later. In this embodiment, the lower surface 24 constitutes a third surface 43 of the exterior body 40 described later. In this embodiment, the first side surface 25 constitutes a second surface 42 of the exterior body 40 described later. The second side surface 26 constitutes a fourth surface 44 of the exterior body 40, which will be described later. However, each of the surfaces 23 to 26 of the electrode body 20 may constitute any one of the first surface 41 to the fourth surface 44 of the exterior body 40. The electrode body 20 has a ridge line portion 20A, a ridge line portion 20B, a ridge line portion 20C, and a ridge line portion 20D. The ridge line portion 20A is formed at the boundary between the upper surface 23 and the first side surface 25. The ridge line portion 20B is formed at the boundary between the upper surface 23 and the second side surface 26. The ridge line portion 20C is formed at the boundary between the first side surface 25 and the lower surface 24. The ridge line portion 20D is formed at the boundary between the second side surface 26 and the lower surface 24. In other words, the ridge line portion refers to the boundary between two surfaces that intersect with each other. The ends of the ridge line portions 20A to 20D become corner portions 230 that correspond to the vertices of a substantially rectangular parallelepiped. 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.

[0017] [Exterior body] The exterior body 40 seals the electrode body 20. The exterior body 40 includes an exterior film 50 and a pair of lid bodies 60. The exterior film 50 wraps the electrode body 20 so as to form a pair of openings 40A. In this embodiment, the exterior film 50 is wrapped around the electrode body 20 so as to form a pair of openings 40A. However, wrapping the electrode body 20 with the exterior film 50 is not limited to wrapping the exterior film 50, and the electrode body 20 may be disposed inside the exterior film 50 that is formed in a cylindrical shape in advance. As a result, the exterior film 50 covers the front surface 21, the back surface 22, the upper surface 23, the lower surface 24, the first side surface 25, the second side surface 26, the ridges 20A to 20D, and the corners 230 of the electrode body 20, and the first surface 41 to the fourth surface 44 described later are formed in the exterior body 40. The exterior film 50 has a protruding portion 50X that protrudes outward from the portion wrapping the electrode body 20 when the electrode body 20 is wrapped around it. The pair of lid bodies 60 are respectively disposed on the sides of the electrode body 20 so as to close the pair of openings 40A.

[0018] 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 cause a decrease in battery performance. On the other hand, in this embodiment, the exterior body 40 seals the electrode body 20 by wrapping the exterior film 50 around the electrode body 20, so that the electrode body 20 can be easily sealed regardless of the thickness of the electrode body 20. Note that in order to reduce the dead space between the electrode body 20 and the exterior film 50 so as to improve the volumetric energy density of the electricity storage device 10 and to improve the cooling efficiency, it is preferable that the exterior film 50 is wrapped so as to contact the outer surface of the electrode body 20. Moreover, in an all-solid-state battery, it is necessary to apply a high pressure uniformly from the outer surface of the battery to exert battery performance, and therefore it is necessary to eliminate the space between the electrode body 20 and the exterior film 50. Therefore, it is preferable that the exterior film 50 is wrapped around the electrode body 20 so as to be in contact with the outer surface of the electrode body 20.

[0019] [Exterior film] Fig. 3 is a cross-sectional view showing the layer structure of the exterior film 50. As shown in Fig. 3, the exterior film 50 is a laminate (laminate film) having, for example, a base layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in this order. Note that the exterior film 50 does not need to include all of these layers, and for example, the barrier layer 52 may not be included. That is, the exterior film 50 may be made of a material that is flexible and easily bendable, and may be made of, for example, a resin film. Note that the exterior film 50 is preferably heat-sealable.

[0020] The base layer 51 included in the exterior film 50 is a layer for imparting heat resistance to the exterior film 50 and suppressing the occurrence of pinholes that may occur during processing or distribution. The base layer 51 is configured to include at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer. For example, the base layer 51 includes at least one layer of a stretched polyester resin layer and a stretched polyamide resin layer, so that the barrier layer 52 can be protected during processing of the exterior film 50 and breakage of the exterior film 50 can be suppressed. In addition, from the viewpoint of increasing the tensile elongation of the exterior film 50, the stretched polyester resin layer is preferably a biaxially stretched polyester resin layer, and the stretched polyamide resin layer is preferably a biaxially stretched polyamide resin layer. Furthermore, in terms of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. The base layer 51 may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the base layer 51 is, for example, preferably 5 to 300 μm, and more preferably 20 to 150 μm, from the viewpoint of film strength.

[0021] 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.

[0022] 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.

[0023] From the viewpoint of improving the formability or conformability of the exterior film 50, the aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, and from the viewpoint of further improving the formability or conformability, the aluminum alloy foil is preferably an iron-containing aluminum alloy foil. In the iron-containing aluminum alloy foil (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. By making the iron content 0.1% by mass or more, an exterior film 50 having better formability can be obtained. By making the iron content 9.0% by mass or less, an exterior film 50 having better flexibility can be obtained. Examples of the soft aluminum alloy foil include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Silicon, magnesium, copper, manganese, etc. may be added as necessary. Softening can be performed by annealing treatment, etc. From the viewpoint of improving the mechanical strength of the exterior film 50, it is more preferable that the aluminum alloy foil is a hard aluminum alloy foil composed of, for example, a work-hardened aluminum alloy. Examples of the hard aluminum alloy foil include aluminum alloy foils having a composition specified in JIS H4160:1994 A8021H-H18, JIS H4160:1994 A8079H-H18, JIS H4000:2014 A8021P-H14, or JIS H4000:2014 A8079P-H14.

[0024] 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.

[0025] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferred.

[0026] In the case of a metal foil, the thickness of the barrier layer 52 should be such that it at least functions as a barrier layer to prevent the intrusion of moisture, and may be, for example, about 5 to 200 μm. The thickness of the barrier layer 52 is preferably about 85 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 52 is preferably about 9.0 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. Preferable ranges for the thickness of the barrier layer 52 include about 9.0 to 85 μm, about 9.0 to 50 μm, about 9.0 to 40 μm, about 9.0 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 52 is made of an aluminum alloy foil, the above-mentioned ranges are particularly preferable. From the viewpoint of imparting high formability and high rigidity to the exterior film 50, the thickness of the barrier layer 52 is preferably about 35 μm or more, more preferably about 45 μm or more, even more preferably about 50 μm or more, and even more preferably about 55 μm or more, and is preferably about 200 μm or less, more preferably about 85 μm or less, even more preferably about 75 μm or less, and even more preferably about 70 μm or less. Preferable ranges are about 35 to 200 μm, about 35 to 85 μm, about 35 to 75 μm, about 35 to 70 μm, about 45 to 200 μm, about 45 to 85 μm, about 45 to 75 μm, about 45 to 70 μm, about 50 to 200 μm, about 50 to 85 μm, about 50 to 75 μm, about 50 to 70 μm, about 55 to 200 μm, about 55 to 85 μm, about 55 to 75 μm, and about 55 to 70 μm. When the exterior film 50 has high formability, deep drawing becomes easy, which can contribute to increasing the capacity of the electricity storage device. Furthermore, when the capacity of the electricity storage device is increased, the weight of the electricity storage device increases, but the rigidity of the exterior film 50 is increased, which can contribute to high sealing performance of the electricity storage device.In particular, when the barrier layer 52 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, even more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Preferred ranges for the thickness of the stainless steel foil include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0027] In addition, when the barrier layer 52 is a metal foil, it is preferable that at least the surface opposite to the base layer 51 is provided with a corrosion-resistant film in order to prevent dissolution and corrosion. The barrier layer 52 may be provided with a corrosion-resistant film on both sides. Here, the corrosion-resistant film refers to a thin film that is provided with corrosion resistance (e.g., acid resistance, alkali resistance, etc.) on the barrier layer 52 by performing, for example, hydrothermal conversion treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or corrosion prevention treatment by applying a coating agent on the surface of the barrier layer 52. Specifically, the corrosion-resistant film refers to a film that improves the acid resistance of the barrier layer 52 (acid-resistant film), a film that improves the alkali resistance of the barrier layer 52 (alkali-resistant film), etc. The treatment for forming the corrosion-resistant film may be one type, or two or more types may be combined. In addition, not only one layer but also multiple layers may be formed. Furthermore, among these treatments, hydrothermal conversion treatment and anodizing treatment are treatments in which the metal foil surface is dissolved by a treatment agent to form a metal compound with excellent corrosion resistance. Note that these treatments may also be included in the definition of chemical conversion treatment. In addition, when the barrier layer 52 has a corrosion-resistant coating, the corrosion-resistant coating is also included in the barrier layer 52.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] When the buffer layer is made of rubber, the lower limit of the thickness of the buffer layer is preferably 0.5 mm. When the buffer layer is made of rubber, the upper limit of the thickness of the buffer layer is preferably 10 mm, more preferably 5 mm, and more preferably 2 mm. When the buffer layer is made of rubber, the preferred range of the thickness of the buffer layer is 0.5 mm to 10 mm, 0.5 mm to 5 mm, or 0.5 mm to 2 mm.

[0033] 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.

[0034] In this embodiment, in a state where the exterior film 50 is wrapped around the electrode body 20 and the lid body 60, the surfaces (thermally adhesive resin layer 53) of the exterior film 50 facing each other are heat-sealed to form the first sealing portion 70 (see FIG. 1). In this embodiment, the first sealing portion 70 extends in the longitudinal direction (FB direction) of the exterior body 40. The position where the first sealing portion 70 is formed in the exterior body 40 can be arbitrarily selected. In this embodiment, the root 70X of the first sealing portion 70 is located on the side 45 of 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. In a plan view, the first sealing portion 70 may protrude outward beyond the electrode body 20, or may be folded toward the first surface 41. In the exterior body 40, the surface facing the first surface 41 is the third surface 43, and the surface facing the second surface is the fourth surface 44. As described above, the first surface 41 to the fourth surface 44 are surfaces corresponding to the upper surface 23, the first side surface 25, the lower surface 24, and the second side surface 26 of the electrode body, respectively.

[0035] [Lid] 4 is a perspective view showing a schematic configuration of the lid body 60. The lid body 60 is a member arranged to close the opening 40A, and is, for example, a plate-like member having a polygonal shape when viewed from the FB direction of the electricity storage device 10. The lid body 60 is made of, for example, resin. The lid body 60 may be formed by, for example, cold forming the exterior film 50. Alternatively, the lid body 60 may be a metal molded product. Furthermore, the material constituting the lid body 60 may contain at least one or more materials selected from the group consisting of metal, metal oxide, carbon fiber reinforced plastic, and rubber.

[0036] The lid body 60 has a first surface 61, a second surface 62, and a lid seal portion 63. The first surface 61 faces the electrode body 20. The second surface 62 is the surface opposite to the first surface 61. The lid seal portion 63 is connected to the first surface 61 and the second surface 62, and is heat-sealed to the heat-fusible resin layer 53 of the exterior film 50 to form a second sealing portion 80.

[0037] The lid seal portion 63 includes a first seal surface 63A, a second seal surface 63B, a third seal surface 63C, and a fourth seal surface 63D. The first seal surface 63A constitutes the upper surface of the lid body 60. The first seal surface 63A extends in a first direction (LR direction in this embodiment) in a front view of the lid body 60. In this embodiment, the second surface 62, which is a surface facing outward in the electricity storage device 10, is the front surface of the lid body 60. The second seal surface 63B and the third seal surface 63C are connected to the first seal surface 63A and constitute the side surface of the lid body 60. The second seal surface 63B and the third seal surface 63C extend in a second direction (UD direction in this embodiment) intersecting with the first direction in a front view of the lid body 60. In this embodiment, the first direction and the second direction are perpendicular to each other in a front view of the lid body 60. The first direction and the second direction do not have to be perpendicular to each other in a front view of the lid 60. The fourth seal surface 63D forms the lower surface of the lid 60. The fourth seal surface 63D extends in the first direction (the LR direction in this embodiment) in a front view of the lid 60.

[0038] When the lid body 60 is plate-shaped, it is preferable that the lid body 60 has a certain degree of thickness so that deformation of the exterior body 40 is suppressed even when the power storage device 10 is arranged in a stacked manner. From another viewpoint, when the lid body 60 is plate-shaped, it is preferable that the lid seal portion 63 of the lid body 60 has a certain degree of thickness so that the lid seal portion 63 of the lid body 60 and the exterior film 50 can be suitably heat-sealed when the second sealing portion 80 is formed. The minimum value of the thickness of the lid body 60 is, for example, 1.0 mm, more preferably 3.0 mm, and even more preferably 4.0 mm. The maximum value of the thickness of the lid body 60 is, for example, 20 mm, more preferably 15 mm, and even more preferably 12 mm. The preferred ranges of the thickness of the material constituting the lid body 60 are 1.0 mm to 20 mm, 1.0 mm to 15 mm, 1.0 mm to 12 mm, 3.0 mm to 20 mm, 3.0 mm to 15 mm, 3.0 mm to 12 mm, 4.0 mm to 20 mm, 4.0 mm to 15 mm, and 4.0 mm to 12 mm. In this embodiment, when the lid body 60 is expressed as a plate-like body, the embodiment in which the lid body 60 is composed only of a film defined by the [packaging terminology] standard of JIS (Japan Industrial Standards) is not included. The thickness of the lid body 60 may vary depending on the part of the lid body 60. When the thickness of the lid body 60 varies depending on the part, the thickness of the lid body 60 is the thickness of the thickest part.

[0039] The lid seal portion 63 further includes boundaries 64, 65, 66, and 67. The boundary 64 is a boundary between the first seal surface 63A and the second seal surface 63B. The boundary 65 is a boundary between the first seal surface 63A and the third seal surface 63C. The boundary 66 is a boundary between the fourth seal surface 63D and the second seal surface 63B. The boundary 67 is a boundary between the fourth seal surface 63D and the third seal surface 63C. The shapes of the boundaries 64 to 67 may be angular, or may be rounded by performing R processing. In this embodiment, the boundaries 64 to 67 are angular.

[0040] From the viewpoint of suitable heat sealing between the lid 60 and the exterior film 50, it is preferable that the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 of the exterior film 50 are mainly made of the same material. In this embodiment, the material constituting the lid 60 and the material constituting the heat-sealable resin layer 53 are mainly made of polypropylene. Note that the main material refers to a material that occupies 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more when the total material contained in the components is taken as 100% by mass.

[0041] In this embodiment, the lid body 60 is formed with a through hole 60X into which the electrode terminal 30 described later is inserted. The through hole 60X penetrates the first surface 61 and the second surface 62. When the electrode body 20 is stored, the electrode terminal 30 protrudes to the outside of the exterior body 40 through the through hole 60X formed in the lid body 60. A small gap between the through hole 60X of the lid body 60 and the electrode terminal 30 is filled with, for example, resin. In the electricity storage device 10, the position from which the electrode terminal 30 protrudes to the outside can be arbitrarily selected. For example, the electrode terminal 30 may protrude to the outside from a hole formed in any one of the six surfaces of the exterior body 40. In this case, a small gap between the exterior body 40 and the electrode terminal 30 is filled with, for example, resin. In the electricity storage device 10, the lid body 60 and the electrode terminal 30 are provided as separate bodies, but the lid body 60 and the electrode terminal 30 may be formed integrally. If the electrode terminals 30 do not protrude from the edge of the exterior body 40, the lid body 60 does not need to have the through-holes 60X formed therein.

[0042] [Electrode terminal] Referring again to FIG. 1, the power storage device 10 according to this embodiment includes a pair of electrode terminals 30. The electrode terminals 30 are metal terminals used for inputting and outputting electric power in the electrode body 20. One end of the electrode terminal 30 is electrically connected to the electrode body 20 (positive electrode or negative electrode). The other end of the electrode terminal 30 protrudes outward from an edge of the exterior body 40, for example. Note that the electrode terminal 30 may not protrude from the exterior body 40, for example, as long as it is capable of inputting and outputting electric power to and from the electrode body 20. When the cover body 60 described later is made of, for example, a metal, the cover body 60 may also function as the electrode terminal 30. In this case, the cover body 60 having the function as an electrode terminal may or may not protrude from the exterior body 40.

[0043] 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 current collecting tab which is the positive electrode is usually made of aluminum, etc., and the electrode terminal 30 connected to the current collecting tab 210 which is the negative electrode is usually made of copper, nickel, etc.

[0044] [Protective material] 1 again, the electricity storage device 10 further includes a protective member 90 and a protective member 91. The protective member 90 and the protective member 91 are arranged on the outside of the corners 230 and the ridges 20A to 20D of the electrode body 20 so as to cover the corners 230 and the ridges 20A to 20D, respectively. In the first embodiment, the protective member 90 and the protective member 91 are arranged on the outside of the exterior body 40 and are joined to the outermost layer of the exterior film 50 or the lid body 60.

[0045] FIG. 5 is a perspective view showing the configuration of the protective member 90. The protective member 90 is a member disposed on the outside of the ridge portions 20B to 20D including the corner portion 230 of the electrode body 20. The protective member 90 extends in the FB direction and has an L-shape when viewed from the FB direction. The protective member 90 has a first surface portion 900 and a second surface portion 901 intersecting with the first surface portion 900. As a result, in this embodiment, one of the three protective members 90 is disposed so as to straddle the second surface 42 and the third surface 43 of the exterior body 40, another protective member 90 is disposed so as to straddle the third surface 43 and the fourth surface 44, and still another protective member 90 is disposed so as to straddle the first surface 41 and the fourth surface 44. As a result, the protective member 90 strengthens the portions of the exterior body 40 corresponding to the ridge portions 20B to 20C of the electrode body 20. Before being placed on exterior body 40, protective member 90 may simply be a plate-like member that does not have an L-shape, and after being joined to exterior body 40, it may have a shape as shown in FIG. 5.

[0046] In this embodiment, the protective member 91 is a member disposed on the outside of the ridge portion 20A of the electrode body 20. The protective member 91 extends in the FB direction and has a flat plate shape when viewed from the UD direction. The protective member 91 is also bonded to the outermost layer of the exterior film 50, similar to the protective member 90. The protective member 91 is preferably disposed on the outside of the ridge portion 20A and on the base 70X of the first sealing portion 70. Since the protruding portion 50X is movable with respect to other parts of the exterior body 40, material fatigue is likely to occur in the protruding portion 50X, particularly in a portion including the base 70X of the first sealing portion 70. In the portion of the exterior film 50 where material fatigue occurs, the barrier layer 52, the base material layer 51, and the thermally adhesive resin layer 53 may peel off, causing cracks, and the exterior film 50 may be damaged. In a typical example, the electricity storage device 10 may be moved to an arbitrary location with the protruding portion 50X (first sealing portion 70) being gripped. In such a case, since the protruding portion 50X moves relative to other portions of the exterior body 40, a portion of the exterior film 50 including the root of the protruding portion 50X, in other words, a portion including the root 70X of the first sealing portion 70, may be damaged, and the sealing performance of the electricity storage device 10 may be reduced. By disposing the protective member 91 on the root 70X of the first sealing portion 70, the movement of the protruding portion 50X is suppressed, and the periphery of the root 70X can be reinforced. In the example of FIG. 1, the protective member 91 is disposed on the 41st surface of the exterior body 40, but in addition to or instead of this, the protective member 91 may be disposed on the second surface 42 of the exterior body 40. Alternatively, the first surface portion 900 and the second surface portion 901 of the protective member 90 may be disposed outside the ridge portion 20A so as to be aligned along the second surface 42 of the exterior body 40 and the lower surface of the protruding portion 50X, respectively. Moreover, in a state where the overhanging portion 50X is folded toward the first surface 41, the protective member 90 may be disposed outside the ridge portion 20A so as to straddle the root 70X of the overhanging portion 50X (first sealing portion 70) folded from the second surface 42. Furthermore, in a state where the overhanging portion 50X is folded toward the second surface 42, the protective member 90 may be disposed outside the ridge portion 20A so as to straddle the root 70X of the overhanging portion 50X (first sealing portion 70) folded from the first surface 41.

[0047] The material forming the protective member 90 and the protective member 91 may contain at least one of resin, metal, metal oxide, carbon material (carbon fiber reinforced plastic, etc.), and rubber material. Among them, a material having cushioning properties is preferable, and examples of such materials include the same as the material constituting the buffer layer of the exterior film 50. In addition, the material forming the protective member 90 and the protective member 91 is preferably an elastically deformable material. In the electricity storage device 10, the internal pressure of the electricity storage device 10 may increase due to volumetric changes in the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charging and discharging, and gas generation, etc. When the internal pressure of the electricity storage device 10 increases, the exterior body 40 may expand and the exterior film 50 may stretch. In addition, when vacuum drawing is performed in the manufacturing process of the electricity storage device 10, the exterior body 40 may shrink. When the protective members 90 and 91 are made of an elastically deformable material, the protective members 90 and 91 can deform in response to the expansion and contraction of the exterior body 40 and are less likely to separate from the exterior film 50, further enhancing the effects described below. Furthermore, when the electrode body 20 contains an electrolyte, the surfaces of the protective members 90 and 91 are preferably made of a material that is resistant to the electrolyte.

[0048] On the other hand, when the protective members 90 and 91 are formed of a material with relatively low stretching and deformability, the protective members 90 and 91 have the additional effect of suppressing the expansion and contraction deformation of the exterior body 40 described above. Specifically, the protective members 90 and 91, which have relatively low stretching and deformability, are present on the outside of the exterior film 50, thereby making it possible to limit the expansion of the exterior body 40. Furthermore, when the protective members 90 and 91 are at least partially joined to the exterior film 50, they reduce the stretching of the exterior film 50 in that portion, making it possible to limit the contraction of the exterior body 40.

[0049] The method of joining the protective member 90 and the protective member 91 to the exterior film 50 is not particularly limited. Examples of the method include a method of interposing an adhesive between the protective member 90 and the protective member 91 and the exterior body 40, a method of fusing the protective member 90 and the protective member 91 and the exterior body 40 with a heat-sealing resin, a method of interposing a tape having an adhesive layer on both sides between the protective member 90 and the protective member 91 and the exterior body 40, a method of forming at least one of the protective member 90 and the protective member 91 into a tape having an adhesive layer on one side and attaching the tape along the ridge of the electricity storage device, and the like.

[0050] <1-2. Actions and Effects of Electricity Storage Devices> The ridges 20A to 20D and corners 230 of the electrode body 20 have a sharper shape than other parts of the electrode body 20, and when an impact is applied to the electricity storage device 10, they come into contact with the exterior film 50 and are likely to damage the exterior film 50. According to the electricity storage device 10, the protective members 90 and 91 cover the parts of the exterior body 40 that correspond to the ridges 20A to 20D and corners 230 of the electrode body 20. As a result, even if an impact is applied to the electricity storage device 10, the exterior film 50 is reinforced in the parts that correspond to the ridges 20A to 20D and corners 230 of the electrode body 20, and damage to the exterior film 50 by the ridges 20A to 20D and corners 230 of the electrode body 20 can be suppressed. As a result, the durability of the electricity storage device 10 is improved.

[0051] [2. Second embodiment] The electricity storage device 10A of the second embodiment is different from the first embodiment in that a protective member 92 is provided instead of the protective members 90 and 91, but other configurations are similar to those of the first embodiment. The electricity storage device 10A of the second embodiment will be described below, focusing on the parts that differ from the first embodiment.

[0052] <2-1. Configuration of the power storage device> FIG. 6 is a perspective view showing a configuration of an electricity storage device 10A of a second embodiment. As shown in FIG. 6, the electricity storage device 10A includes a protective member 92. The protective member 92 includes three first parts 920, a second part 921, and two third parts 922. The first parts 920 are disposed outside the ridge lines 20B to D, respectively, similar to the protective member 90. The second part 921 is disposed outside the ridge line 20A, similar to the protective member 91. The third parts 922 are disposed outside the pair of lid bodies 60, respectively. The first part 920, the second part 921, and the third part 922 are connected to each other. Note that the third part 922 may have a through hole 92X formed therein for exposing the tip of the electrode terminal 30. The third part 922 may be configured to cover only the peripheral edge of the lid body 60.

[0053] The first parts 920 each extend in the FB direction and have an L shape when viewed from the FB direction.

[0054] The second part 921 extends in the FB direction and has a flat plate shape when viewed from the UD direction. Both ends of the second part 921 in the FB direction are connected to the third part 922. The second part 921 is preferably disposed outside the ridge portion 20A and on the base 70X of the first sealing portion 70. The reason for this is as already described in the first embodiment.

[0055] Fig. 7 is a perspective view showing the configuration of the third part 922. The third part 922 has a plate-shaped wall portion 9220 facing the second surface 62 of the lid body 60, and a side wall portion 9221 standing from the periphery of the wall portion 9220 and covering at least a part of the lid seal portion 63 from the outside of the exterior film 50. That is, in this embodiment, the third part 922 is formed in a substantially container shape. Note that, for convenience of explanation, other elements that may be formed in the third part 922, such as through holes and slits, are omitted in Fig. 7.

[0056] The third part 922 may have a function of reinforcing the seal of the second sealing part 80 by covering the lid seal part 63 of the lid body 60, the part of the exterior film 50 facing the lid seal part 63, and at least a part of the second surface 62 of the lid body 60. In this case, the third part 922 is preferably formed including a material that does not transmit gas or moisture, or is formed including a layer that does not transmit gas or moisture. When the lid seal part 63 and the heat-fusible resin layer 53 of the exterior film 50 are heat-sealed, if the length of the exterior film 50 is greater than the length of the lid seal part 63, sagging may occur in the exterior film 50, and the second sealing part 80 may not be formed in part. If such a seal failure occurs, at least one of gas and moisture may penetrate into the exterior body 40, or if the electricity storage device 10 has an electrolyte, the electrolyte may leak out of the exterior body 40. When third part 922 covers both lid seal portion 63 and exterior film 50 and reinforces the seal by second sealing portion 80, even if a seal defect occurs in second sealing portion 80, it is possible to prevent at least one of gas and moisture from entering exterior body 40 and the electrolyte from leaking out of exterior body 40. In other words, the gap between exterior film 50 and lid body 60 can be sealed more reliably.

[0057] Furthermore, when the third part 922 is formed in the above-mentioned container shape, the third part 922 may be joined to the exterior body 40 by interposing a curable resin between the third part 922 and the lid body 60 (particularly, the lid seal portion 63). The curable resin is a resin that includes at least one of a photocurable resin, a room temperature curable resin, a thermosetting resin, and an electron beam curable resin. Among them, it is preferable to include at least one of a photocurable resin and a room temperature curable resin. The photocurable resin is a resin that is cured by irradiation with light of a specific wavelength. Examples of the photocurable resin include a radical polymerization resin that is cured by radicalizing a photopolymerization initiator when irradiated with ultraviolet light and a radical chain reaction with a functional group of a monomer or an oligomer, and a cationic polymerization resin that is cured by starting a cationic polymerization reaction when irradiated with ultraviolet light. An example of the radical polymerization resin is an acrylic resin, and an example of the cationic polymerization resin is an epoxy resin, a vinyl ether, and the like. Examples of room temperature curable resins include resins that are mainly made of epoxy resins, ester resins, or acrylic resins and are cured by mixing with a curing agent. Examples of thermosetting resins include phenol resins, epoxy resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, silicone resins, polyurethane, and thermosetting polyimides. Examples of electron beam curable resins include acrylic resins. By filling the space between the lid 60 and the third part 922 with these curable resins, even if a sealing defect occurs in the second sealing portion 80, it is possible to more reliably prevent gas or moisture from entering through the sealing defect and prevent the electrolyte from leaking to the outside of the electricity storage device 10A.

[0058] The method of connecting the first part 920 and the second part 921 to the third part 922 is not particularly limited. For example, the first part 920 and the third part 922 can be connected by forming an engaging portion on one of them and forming an engaged portion on the other of them and engaging them. Similarly, the second part 921 and the third part 922 can be connected by forming an engaging portion on one of them and forming an engaged portion on the other of them and engaging them. The engaging portion is, for example, a convex portion, and the engaged portion is, for example, a concave portion into which the convex portion can be fitted and fixed. In addition to or instead of this, the first part 920 and the third part 922, and the second part 921 and the third part 922 may be joined to each other by an adhesive, may be joined to each other by a tape having an adhesive layer, or may be fused to each other by a heat-sealable resin. The first part 920 to the third part 922 may be connected together and then attached to the exterior body 40 that seals the electrode body 20, or may be connected at the same time as being attached to the exterior body 40 that seals the electrode body 20. Also, the first part 920, the second part 921, and the third part 922 may be formed integrally. In this case, the protective member 92 is preferably formed from a deformable material so that it can be attached to the exterior body 40.

[0059] The first part 920 to the third part 922 can be formed from the same material as the material forming the protective member 90 and the protective member 91, respectively. The material forming each part may be different for each part, or may be the same. In addition, the method of joining the first part 920 to the second part 921 to the exterior film 50 is not particularly limited. For example, as with the protective member 90 and the protective member 91, a method of interposing an adhesive between the first part 920 to the second part 921 and the exterior body 40, a method of fusing between the first part 920 to the second part 921 and the exterior body 40 with a heat-sealing resin, a method of interposing a tape having an adhesive layer on both sides between the first part 920 to the second part 921 and the exterior body 40, a method of forming at least one of the first part 920 to the second part 921 into a tape having an adhesive layer on one side and attaching this along the ridge line of the electricity storage device, and the like can be mentioned. Third part 922 can also be joined to lid 60 and exterior film 50 in the same manner as first part 920 to second part 921, in addition to or instead of the methods already described.

[0060] <2-2. Actions and Effects of Electricity Storage Devices> According to the power storage device 10A of the second embodiment, it is possible to achieve the same effect as the power storage device 10 of the first embodiment. That is, when the first part 920 to the third part 922 are formed of an elastically deformable material, the first part 920 to the third part 922 can deform in response to the expansion and contraction of the exterior body 40 caused by the internal pressure change of the power storage device 10A, and are difficult to separate from the exterior film 50. As a result, even if an impact is applied to the power storage device 10A, the exterior film 50 is reinforced in the portions corresponding to the ridge lines 20A to 20D and the corners 230 of the electrode body 20, and it is possible to suppress damage to the exterior film 50 by the ridge lines 20A to 20D and the corners 230 of the electrode body 20. Furthermore, when the third part 922 is formed so as to reinforce the sealing by the second sealing portion 80, even if a partial unsealed portion occurs in the second sealing portion 80, that portion is covered by the third part 922. This allows the gap between the exterior film 50 and the lid 60 to be sealed more reliably.

[0061] When the first part 920 to the third part 922 are formed of a material with relatively low elastic deformation, the protective member 92 has an additional effect of suppressing the above-mentioned elastic deformation of the exterior body 40. In the electricity storage device 10A, the internal pressure of the electricity storage device 10A may increase due to volume changes of the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charging and discharging, and gas generation, etc. When the internal pressure of the electricity storage device 10A increases, the exterior body 40 may expand. The protective member 92, which has relatively low elastic deformation, is present on the outside of the exterior film 50, so that the above-mentioned expansion of the exterior body 40 can be limited. Furthermore, when vacuum drawing is performed in the manufacturing process of the electricity storage device 10A, the exterior body 40 may shrink. When the protective member 92 is at least partially joined to the exterior film 50, the protective member 92 reduces the elasticity of the exterior film 50 in that portion, thereby suppressing such elastic deformation of the exterior body 40.

[0062] [3. Third embodiment] The electricity storage device 10B of the third embodiment is different from the first embodiment in that it includes a protective member 93 instead of the protective members 90 and 91, and the protective member 93 is disposed inside the exterior body 40, but other configurations are similar to those of the first embodiment. The following describes the electricity storage device 10B of the third embodiment, focusing on the parts that differ from the first embodiment.

[0063] <3-1. Configuration of the power storage device> 8 is a perspective view showing the configuration of an electricity storage device 10B of the third embodiment (however, the electrode terminals 30 are omitted from the illustration). In the electricity storage device 10B, a protective member 93 is disposed between the electrode body 20 and the exterior body 40. That is, the protective member 93 is sealed in the exterior body 40 together with the electrode body 20.

[0064] 9 is a perspective view showing the configuration of the electrode body 20 and protective member 93 of the electricity storage device 10B. The protective member 93 has two sidewalls 930 facing the front surface 21 and the back surface 22 of the electrode body 20, and four frame portions 931 connecting the two sidewalls 930 between them. The sidewalls 930 are plate-like members arranged at intervals in the FB direction. The frame portions 931 are columnar members extending in the FB direction and connected to the two sidewalls 930. The electrode body 20 can be arranged in a space defined by the sidewalls 930 and the frame portions 931.

[0065] When the electrode body 20 is disposed inside the protective member 93, the four frame portions 931 are disposed outside the ridge portions 20A to 20D of the electrode body 20, respectively, and prevent the corner portions 230 and the ridge portions 20A to 20D from contacting the exterior film 50. That is, the frame portions 931 function as a buffer material between the corner portions 230 and the ridge portions 20A to 20D and the exterior film 50. As long as the corner portions 230 and the ridge portions 20A to 20D can be prevented from contacting the exterior film 50, the shape of the frame portions 931 viewed from the FB direction is not particularly limited, and may be, for example, an L-shape, a rectangle, a circle, a semicircle, a polygon, or the like. The frame portions 931 may contact the exterior film 50 at the outermost position of the protective member 93. For this reason, it is preferable that at least a portion of the frame portions 931 that may contact the exterior film 50 is rounded so as not to damage the exterior film 50.

[0066] The side wall portions 930 are arranged so that one of them faces the front surface 21 of the electrode body 20 and the other faces the back surface 22 of the electrode body 20. When the electrode body 20 is arranged inside the protective member 93, the two side wall portions 930 are arranged outside the ridge portions 20A to 20D of the electrode body 20, respectively, and prevent the corner portions 230 and the ridge portions 20A to 20D from contacting the exterior film 50. In other words, the side wall portions 930 function as a buffer material between the corner portions 230 and the ridge portions 20A to 20D and the exterior film 50. For this reason, it is preferable that at least a portion of the side wall portions 930 that may come into contact with the exterior film 50 is rounded so as not to damage the exterior film 50. For example, the side wall portions 930 have a substantially rectangular shape when viewed from the FB direction, and it is preferable that a portion corresponding to the vertex of the rectangle is rounded.

[0067] The side wall portion 930 may be provided with a through hole (not shown) for passing the current collecting tab of the electrode body 20 through. In this case, the current collecting tab can be made to protrude from the through hole of the side wall portion 930 to the outside of the protective member 93 and further electrically connected to the electrode terminal 30. Alternatively, the current collecting tab may be provided on the electrode body 20 so as to protrude in another direction, and may protrude from between the frame portions 931 to the outside of the protective member 93.

[0068] Materials for forming the side wall portion 930 and the frame portion 931 include the same materials as those listed in the first embodiment. Among them, materials having cushioning properties are preferable, and examples of such materials include the same materials as those constituting the buffer layer of the exterior film 50. In addition, the materials for forming the side wall portion 930 and the frame portion 931 are preferably elastically deformable materials. When the side wall portion 930 and the frame portion 931 are formed from an elastically deformable material, the protective member 93 can deform in response to the volume change of the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charging and discharging, and the effects described below can be further enhanced. Furthermore, when the electrode body 20 has an electrolyte, the surfaces of the side wall portion 930 and the frame portion 931 are preferably made of a material resistant to the electrolyte. Note that the materials for forming the side wall portion 930 and the frame portion 931 may be different from each other or may be the same.

[0069] On the other hand, when the side wall portion 930 and the frame portion 931 are formed of a material with a relatively low elastic deformation property and are at least partially joined to the innermost layer of the exterior film 50, the protective member 93 has an additional effect of suppressing the expansion and contraction deformation of the exterior body 40. In the electricity storage device 10B, the internal pressure of the electricity storage device 10B may increase due to a change in volume of the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charging and discharging, and gas generation, etc. When the internal pressure of the electricity storage device 10B increases, the exterior body 40 may expand. Furthermore, when vacuum drawing is performed in the manufacturing process of the electricity storage device 10B, the exterior body 40 may shrink. The protective member 93 is at least partially joined to the exterior film 50, thereby reducing the elasticity of the exterior film 50 in that portion, and therefore the above-mentioned expansion and contraction deformation of the exterior body 40 can be limited.

[0070] <3-2. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10B of the third embodiment, the protective member 93 functions as a buffer material that prevents the ridges 20A to 20D and the corners 230 of the electrode body 20 from coming into contact with the exterior film 50. This prevents a particularly sharp portion of the electrode body 20 from impacting the exterior film 50 and damaging the exterior film 50. Furthermore, when the protective member 93 itself is made of an elastic material or when the portion that contacts the exterior film 50 is rounded, damage to the exterior film 50 can be more reliably prevented. Furthermore, the protective member 93 protects the electrode body 20 against impacts applied from the outside of the electricity storage device 10B. This in turn improves the durability of the electricity storage device 10B.

[0071] [4. Fourth embodiment] The electricity storage device 10C of the fourth embodiment is different from the third embodiment in that it includes a protective member 94 instead of the protective member 93, and the protective member 94 is configured to include a lid body 60, but other configurations are similar to those of the third embodiment. The electricity storage device 10C of the fourth embodiment will be described below, focusing on the parts that differ from the third embodiment.

[0072] <4-1. Configuration of the power storage device> FIG. 10 is a perspective view showing the configuration of an electricity storage device 10C of the fourth embodiment (however, the electrode terminals 30 are omitted from the illustration). The protective member 94 has a pair of lid bodies 60 and four frame portions 940 that connect the pair of lid bodies 60 between them. The configuration of the lid bodies 60 is the same as the configuration of the lid bodies 60 according to the first to third embodiments. Moreover, each of the frame portions 940 is a columnar member that extends in the FB direction and is connected to the pair of lid bodies 60, and the configuration is the same as the frame portion 931 of the third embodiment. The electrode body 20 can be disposed in a space defined by the lid bodies 60 and the frame portions 940.

[0073] <4-2. Actions and Effects of Electricity Storage Devices> According to the electricity storage device 10C of the fourth embodiment, it is possible to achieve the same effects as the electricity storage device 10B of the third embodiment. Moreover, according to the electricity storage device 10C of the fourth embodiment, the pair of lid bodies 60 also serve as part of the protective member 94. This makes it possible to configure the protective member 94 without excessively increasing the number of parts.

[0074] [5. Modifications] The above-mentioned embodiments are examples of forms that the power storage device according to the present invention can take, and are not intended to limit the forms. The power storage device according to the present invention can take forms different from those exemplified in the respective embodiments. One example is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Below, some examples of modified versions of each embodiment are shown. The above-mentioned embodiments and the following modified versions can be combined with each other as long as there is no technical contradiction.

[0075] (1) In the power storage device 10A of the second embodiment, the third part 922 does not have to be formed in a substantially container shape. For example, the wall surface portion 9220 may have a through hole through which the electrode terminal 30 passes. The wall surface portion 9220 may be configured in a frame shape so as to cover only the peripheral portion of the second surface 62 of the lid 60. The third part 922 may have a slit or the like in the side wall portion 9221 to pass the overhang portion 50X so as not to interfere with the overhang portion 50X. Furthermore, the side wall portion 9221 may be omitted in the third part 922, and only the wall surface portion 9220 may be included.

[0076] (2) In the power storage device 10 of the first embodiment, when the base 70X of the first sealing portion 70 is formed at another position, such as on the surface of the exterior body 40, the configuration of the protective member 91 may be appropriately changed to match the position of the base 70X or may be omitted. Similarly, in the power storage device 10A of the second embodiment, when the base 70X of the first sealing portion 70 is formed at another position, such as on the surface of the exterior body 40, the configuration of the second part 921 may be appropriately changed to match the position of the base 70X or may be omitted.

[0077] (3) In the electricity storage devices 10, 10A to 10C of the first to fourth embodiments, the exterior film 50 may protrude outward beyond the lid body 60 in the FB direction. The portion of the exterior film 50 protruding beyond the lid body 60 may be folded like a Gabeltop pouch or a brick pouch. The portion of the exterior film 50 protruding beyond the lid body 60 may be folded so as to fit along the second surface 62 of the lid body 60.

[0078] (4) In the electricity storage devices 10, 10A to 10C of the first to fourth embodiments, the external shape of the exterior body 40 can be changed arbitrarily. For example, the cover body 60 does not have to be rectangular when viewed from the FB direction, and may be another polygonal shape, a substantially circular shape, or a substantially elliptical shape. The shape of the cover body 60 may be changed, for example, according to the three-dimensional shape of the electrode body 20. The shapes of the protective members 90 to 94 may also be appropriately changed, for example, according to the three-dimensional shape of the electrode body 20. For example, the shapes of the protective member 90 and the first part 920 when viewed from the FB direction may not be L-shaped, but may be, for example, rectangular, circular, semicircular, polygonal, etc. Note that, for example, when the electrode body 20 is substantially cylindrical, the boundary between the end face in the axial direction of the cylinder and the side peripheral surface of the cylinder becomes the ridge part of the electrode body 20.

[0079] (5) In the electricity storage devices 10, 10A to 10C of the first to third embodiments, an adhesive film (not shown) may be bonded to the outer peripheral surface of the electrode terminal 30. Any adhesive film can be selected as long as it can bond the electrode terminal 30 made of metal and the lid body 60 made of, for example, resin. For example, the adhesive film can be a polyolefin resin such as a polyethylene resin or a polypropylene resin, a cyclic polyolefin resin, or an acid-modified polyolefin resin obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. The adhesive film can be a single layer or two or more layers of these films.

[0080] (6) In the electricity storage device 10B of the third embodiment, the protective member 93 is configured as a separate member from the exterior film 50. However, a member corresponding to at least the frame portion 931 of the protective member 93 may be joined in advance to the innermost layer of the exterior film 50 so that when the electrode body 20 is wrapped with the exterior film 50, the frame portion 931 comes into contact with the ridge portions 20A to 20D of the electrode body 20. This also applies to the frame portion 940 of the electricity storage device 10C of the fourth embodiment. Note that the protective member 93 of the third embodiment and the protective member 94 of the fourth embodiment may be combined with the protective member 90 of the first embodiment or the protective member 91 of the second embodiment, respectively.

[0081] (7) When the protective members 90 to 94 of the first to fourth embodiments have a function of suppressing deformation of the exterior body 40 described above, the protective members 90 to 94 may be configured to selectively suppress deformation of a specific surface of the exterior body 4 depending on the manner in which the power storage devices 10, 10A to 10C are used. For example, as shown in FIG. 11, the power storage devices 10, 10A to 10C are arranged and used such that the fourth surfaces 44 of the power storage devices 10, 10A to 10C are in contact with the cooling mechanism 200. In the power storage devices 10, 10A to 10C arranged as shown in FIG. 11, the fourth surfaces 44 are in contact with the cooling mechanism 200, and the third surfaces 43 are in direct contact with the first surfaces 41 of the adjacent power storage devices 10, 10A to 10C, or indirect contact with them via a plate-like member, a buffer material, or the like. For this reason, for example, when considering expansion as one mode of deformation of the exterior body 40, in the energy storage devices 10, 10A-10C arranged as shown in FIG. 11, the first surface 41, the third surface 43 and the fourth surface 44 of the exterior body 40 are relatively resistant to expansion even when the internal pressure of the energy storage devices 10, 10A-10C increases.

[0082] On the other hand, the second surface 42 of the exterior body 40 is not in contact with other elements such as the electricity storage devices 10, 10A to 10C, and is therefore prone to expansion when the internal pressure of the electricity storage devices 10, 10A to 10C rises. For this reason, in the electricity storage devices 10, 10A, the protective members 90 to 92 can be configured to extend over a wider area on the second surface 42 of the exterior body 40, for example, to suppress the expansion of the second surface 42. On the other hand, in the electricity storage devices 10B, 10C, the side wall portion 930, the frame portion 931, the frame portion 940, or the lid body 60, a portion that is present on the back side of the second surface 42 and the innermost layer of the exterior film 5 that faces the portion can be joined, for example, to suppress the expansion of the second surface 42. In this way, the protective members 90 to 94 can be configured to suppress the expansion of a specific surface of the exterior body 40. The above configuration applies not only to the expansion of the exterior body 40, but also to its contraction. [Explanation of symbols]

[0083] 10, 10A, 10B, 10C: Electricity storage device 20: Electrode body 20A~20D: Ridge 30: Electrode terminal 40: Exterior body 40A: Opening 50: Exterior film 60: Lid 90~94: Protective materials 230: Corner

Claims

1. An electrode body having a three-dimensional shape including upper and lower surfaces and ridges spaced apart in the vertical direction; an exterior film that covers at least one of the ridge lines and wraps the electrode body; a first protective member that is disposed inside the exterior film and has frame portions that are disposed apart in the vertical direction along each of the ridge portions that are spaced apart in the vertical direction; Energy storage device.

2. Further comprising a second protective member arranged on the outside of the exterior film along at least one of the ridge portions. The power storage device according to claim 1 .

3. The first protective member further has a side wall portion connected to the frame portion arranged at a distance in the vertical direction. The electricity storage device according to claim 1 or 2.

4. The first protective member has a space defined by the frame portion and the side wall portion in which the electrode body can be arranged. The electricity storage device according to claim 3 .

5. The portion of the side wall portion that comes into contact with the exterior film is rounded. The electricity storage device according to claim 3 .

6. The side wall portion has a through hole formed therein for allowing the current collecting tab of the electrode body to pass therethrough. The electricity storage device according to claim 3 .

7. The material constituting the first protective member includes at least one of a material having cushioning properties, a material capable of elastic deformation, a material resistant to an electrolyte, and a material having low elastic deformation properties. The electricity storage device according to claim 1 or 2.

8. The electrode body has two surfaces connected via one of the ridge portions, The first protective member has a first surface portion and a second surface portion connected to the first surface portion, and is configured so that the first surface portion and the second surface portion span the two surfaces. The electricity storage device according to claim 1 or 2.

9. A protective member for use in an electricity storage device, comprising: The power storage device is An electrode body having a three-dimensional shape including upper and lower surfaces and ridges spaced apart in the vertical direction; an exterior film that covers at least one of the ridge lines and wraps the electrode body; The protective member is a frame portion disposed on the inside of the exterior film and spaced apart in the vertical direction along each of the ridge lines spaced apart in the vertical direction; Protective material.

10. An exterior film for use in an electricity storage device, comprising: The protective member according to claim 9 is bonded to the Exterior film.

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