Power storage device and protective member for power storage device

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 a power storage device and a protective member for a power storage device.

Background Art

[0002] Patent Document 1 discloses an all-solid-state battery as an example of a power 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-like belt-shaped member that is wound around the all-solid-state battery laminate so as to have an opening, and a lid body that is disposed in the opening. The electrode terminal is electrically connected to the all-solid-state battery laminate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power storage device such as that of Patent Document 1, a film-like belt-shaped member is wound around a side surface including a ridge line of the all-solid-state battery laminate. However, such a film-like belt-shaped member is likely to be damaged at corners and ridge line portions in the three-dimensional shape of the all-solid-state battery laminate, reducing the durability of the power storage device. This is not limited to the all-solid-state battery laminate and applies generally to the case where an electrode body having a three-dimensional shape including corners and ridge line portions is wrapped with an exterior film. This point is not considered in Patent Document 1.

[0005] An object of the present invention is to provide a power storage device with improved durability.

Means for Solving the Problems

[0006] The power storage device according to the first aspect of the present invention includes an electrode body having a three-dimensional shape including ridge lines, an exterior film that covers at least one of the ridge lines and wraps the electrode body, and a protective member disposed outside the electrode body along at least one of the ridge lines.

[0007] The power storage device according to the second aspect of the present invention is the power storage device according to the first aspect, wherein the protective member is disposed outside the exterior film.

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

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

[0010] The protective member according to the sixth aspect of the present invention is a protective member for a power storage device, wherein the power storage device includes an electrode body having a three-dimensional shape including ridge lines, and an exterior film that covers at least one of the ridge lines and wraps the electrode body. The protective member is disposed outside the electrode body along at least one of the ridge lines.

Advantages of the Invention

[0011] According to the present invention, a power storage device with improved durability is provided.

Brief Description of the Drawings

[0012]

Figure 1

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Figure 10

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Embodiments for Carrying Out the Invention

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

[0014] [1. First Embodiment] <1-1. Configuration of Power Storage Device> FIG. 1 is a perspective view schematically showing the power storage device 10 of the first embodiment. The power storage device 10 includes an electrode body 20, a pair of electrode terminals 30, an exterior body 40, and protection members 90 and 91. In FIG. 1, the UD direction of the arrow indicates the thickness direction of the power storage device 10, the LR direction of the arrow indicates the width direction of the power storage device 10, and the FB direction of the arrow indicates the depth direction of the power storage device 10. The directions indicated by each of the arrows UD, LR, and FB are common in each of the subsequent figures.

[0015] [Electrode body] FIG. 2 is a side view schematically showing the configuration of the electrode body 20. The electrode body 20 includes, for example, electrodes (a positive electrode and a negative electrode) constituting a power storage member such as a lithium ion battery, a capacitor, or an all-solid-state battery, a semi-solid-state battery, a quasi-solid-state battery, a polymer battery, an all-resin battery, a lead storage battery, a nickel-hydrogen storage battery, a nickel-cadmium storage battery, a nickel-iron storage battery, a nickel-zinc storage battery, a silver oxide-zinc storage battery, a metal-air battery, a polyvalent cation battery, or a capacitor, and a separator and the like. In the present embodiment, the electrode body 20 has a substantially rectangular parallelepiped shape. Note that the “substantially rectangular parallelepiped” includes, in addition to a perfect 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 a plurality of corners, such as a substantially polygonal prism, or may have a substantially cylindrical shape.

[0016] As shown in FIG. 2, in the present embodiment, the electrode body 20 has a front surface 21, a back 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 respectively coincide with the upper surface and the lower surface in the laminated structure of the electrode body 20. Also, the front surface 21, the back surface 22, the first side surface 25, and the second side surface 26 are virtual surfaces when the electrode body 20 is regarded as a substantially rectangular parallelepiped with reference to the upper surface 23 and the lower surface 24. The front surface 21 faces one lid body 60. The back surface 22 faces the other lid body 60. In the present embodiment, the upper surface 23 constitutes the first surface 41 of the exterior body 40 described later. In the present embodiment, the lower surface 24 constitutes the third surface 43 of the exterior body 40 described later. In the present embodiment, the first side surface 25 constitutes the second surface 42 of the exterior body 40 described later. The second side surface 26 constitutes the fourth surface 44 of the exterior body 40 described later. However, each of the surfaces 23 to 26 of the electrode body 20 may constitute any 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. That is, the ridge line portion refers to the boundary between two surfaces that intersect each other. The ends of the respective ridge line portions 20A to 20D become corner portions 230 corresponding to the vertices of the substantially rectangular parallelepiped. Note that 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 such that a pair of openings 40A are formed. In the present embodiment, the exterior film 50 is wound around the electrode body 20 such that a pair of openings 40A are formed. However, wrapping the electrode body 20 with the exterior film 50 is not limited to winding, and the electrode body 20 may be disposed inside the exterior film 50 formed in a cylindrical shape in advance. Thereby, 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 ridge line portions 20A to 20D, and the corner portion 230 of the electrode body 20, and in the exterior body 40, the first surface 41 to the fourth surface 44 described later are formed. The exterior film 50 has an overhanging portion 50X that protrudes outward from the portion that wraps the electrode body 20 in a state of wrapping the electrode body 20. The pair of lid bodies 60 are respectively disposed on the sides of the electrode body 20 so as to close the pair of openings 40A.

[0018] For example, there is a method of forming a housing portion (depression) for housing the electrode body 20 in the exterior film 50 through cold forming. However, it is not always easy to form a deep housing portion by such a method. If an attempt is made to deeply form the housing portion (depression) by cold forming (for example, a forming depth of 15 mm), pinholes or cracks may occur in the exterior film 50, increasing the possibility of deterioration of battery performance. On the other hand, in the present embodiment, since the exterior body 40 seals the electrode body 20 by winding the exterior film 50 around the electrode body 20, the electrode body 20 can be easily sealed regardless of the thickness of the electrode body 20. In order to reduce the dead space between the electrode body 20 and the exterior film 50 to improve the volumetric energy density of the power storage device 10, and in order to improve the cooling efficiency, a state in which the exterior film 50 is wound so as to contact the outer surface of the electrode body 20 is preferable. Also, in all-solid-state batteries, from the viewpoint that it is necessary to uniformly apply a high pressure from the outside of the battery to exhibit battery performance, it is also necessary to eliminate the space between the electrode body 20 and the exterior film 50, so a state in which the exterior film 50 is wound so as to contact the outer surface of the electrode body 20 is preferable.

[0019] [Outer packaging film] FIG. 3 is a cross-sectional view showing the layer structure of the outer packaging film 50. As shown in FIG. 3, the outer packaging film 50 is a laminate (laminated film) having, for example, a base material layer 51, a barrier layer 52, and a heat-sealable resin layer 53 in this order. Note that the outer packaging film 50 does not necessarily include all of these layers. For example, the barrier layer 52 may not be included. That is, the outer packaging film 50 may be made of a material having flexibility and being easy to bend, and may be made of, for example, a resin film. Note that the outer packaging film 50 is preferably heat-sealable.

[0020] The base material layer 51 included in the outer packaging film 50 is a layer for imparting heat resistance to the outer packaging film 50 and suppressing the generation of pinholes that may occur during processing or distribution. The base material layer 51 is configured to include at least one of, for example, a stretched polyester resin layer and a stretched polyamide resin layer. For example, by including at least one of a stretched polyester resin layer and a stretched polyamide resin layer in the base material layer 51, the barrier layer 52 can be protected during processing of the outer packaging film 50, and breakage of the outer packaging film 50 can be suppressed. Also, from the viewpoint of increasing the tensile elongation of the outer packaging 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. Further, from the viewpoint of excellent puncture strength or impact strength, the stretched polyester resin layer is more preferably a biaxially stretched polyethylene terephthalate (PET) film, and the stretched polyamide resin layer is more preferably a biaxially stretched nylon (ONy) film. Note that the base material layer 51 may be configured to include both a stretched polyester resin layer and a stretched polyamide resin layer. The thickness of the base material layer 51 is preferably, for example, 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 suppresses the ingress of moisture. The barrier layer 52 is joined to the base material layer 51 via, for example, an adhesive layer 54. Examples of the barrier layer 52 include a metal foil having barrier properties, a vapor deposition film, a resin layer, etc. Examples of the vapor deposition film include a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, etc. Examples of the resin layer include polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having a fluoroalkyl group, and fluorine-containing resins such as polymers mainly composed of fluoroalkyl units, ethylene vinyl alcohol copolymers, etc. Further, examples of the barrier layer 52 also include a resin film provided with at least one layer of these vapor deposition films and resin layers. A plurality of barrier layers 52 may be provided. The barrier layer 52 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 52 include aluminum alloys, stainless steels, titanium steels, steel plates, etc. When used as a metal foil, it preferably includes 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-described metal material may contain a recycled material of the metal material. Examples of the recycled material of the metal material include recycled materials of aluminum alloys, stainless steels, titanium steels, or steel plates. These recycled materials can be obtained by known methods respectively. The recycled material of the aluminum alloy can be obtained, for example, by the production method described in International Publication No. 2022 / 092231. The barrier layer 52 may be composed only of recycled materials, or may be composed of a mixed material of recycled materials and virgin materials. Note that the recycled material of the metal material refers to a metal material that has been recovered, isolated, purified, etc. from various products used in the market, waste from the manufacturing process, etc. and made reusable. Also, the virgin material of the metal material refers to a new metal material refined from natural resources (raw materials) of the metal and not a recycled material.

[0023] The aluminum alloy foil is preferably a soft aluminum alloy foil made of, for example, an annealed aluminum alloy, etc., from the viewpoint of improving the formability or followability of the exterior film 50, and is preferably an aluminum alloy foil containing iron from the viewpoint of further improving the formability or followability. In the aluminum alloy foil containing iron (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. When the iron content is 0.1% by mass or more, an exterior film 50 having better formability can be obtained. When the iron content is 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 defined by JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Also, 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, the aluminum alloy foil is more preferably a hard aluminum alloy foil made of, for example, a work-hardened aluminum alloy, etc. Examples of the hard aluminum alloy foil include aluminum alloy foils having a composition defined by 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-hardening stainless steel foils. From the viewpoint of providing an exterior film 50 having better formability, the stainless steel foil is preferably composed of austenitic stainless steel.

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

[0026] In the case of a metal foil, the thickness of the barrier layer 52 only needs to exhibit a function as a barrier layer that at least suppresses the intrusion of moisture, and for example, it can be 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, still more preferably about 40 μm or less, and particularly preferably about 35 μm or less. Also, the thickness of the barrier layer 52 is preferably about 9.0 μm or more, still more preferably about 20 μm or more, and more preferably about 25 μm or more. Also, as the preferable range of the thickness of the barrier layer 52, there are 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, about 25 to 35 μm. When the barrier layer 52 is composed of an aluminum alloy foil, the above-described range is particularly preferable. Also, 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, still more preferably about 50 μm or more, and still more preferably about 55 μm or more, and is also preferably about 200 μm or less, more preferably about 85 μm or less, still more preferably about 75 μm or less, and still more preferably about 70 μm or less. The preferable range is 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, about 55 to 70 μm. When the exterior film 50 has high formability, deep drawing forming becomes easy, which can contribute to increasing the capacity of the power storage device. Also, when the capacity of the power storage device is increased, the weight of the power storage device increases, but by increasing the rigidity of the exterior film 50, it can contribute to the high sealing performance of the power storage device.In particular, when the barrier layer 52 is made of a stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, even more preferably about 30 μm or less, and particularly preferably about 25 μm or less. Also, the thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Also, the preferable range of the thickness of the stainless steel foil includes 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] When the barrier layer 52 is a metal foil, it is preferable to provide a corrosion-resistant film on at least the surface opposite to the base material layer 51 in order to prevent dissolution and corrosion. The barrier layer 52 may be provided with corrosion-resistant films on both sides. Here, the corrosion-resistant film refers to, for example, a thin film that is formed by performing a hot water conversion treatment such as a boehmite treatment, a chemical conversion treatment, an anodizing treatment, a plating treatment such as nickel or chromium, or a corrosion prevention treatment of applying a coating agent on the surface of the barrier layer 52 to provide the barrier layer 52 with corrosion resistance (such as acid resistance and alkali resistance). Specifically, the corrosion-resistant film means 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), and the like. As the treatment for forming the corrosion-resistant film, one type may be performed, or two or more types may be combined. Also, it can be made into multiple layers instead of just one layer. Furthermore, among these treatments, the hot water conversion treatment and the anodizing treatment are treatments that dissolve the surface of the metal foil with a treatment agent and form a metal compound having excellent corrosion resistance. Note that these treatments may be included in the definition of the chemical conversion treatment. Also, when the barrier layer 52 is provided with a corrosion-resistant film, the barrier layer 52 includes the corrosion-resistant film.

[0028] The corrosion-resistant film prevents delamination between the barrier layer 52 (e.g., aluminum alloy foil) and the base material layer 51 during the molding of the outer packaging film 50, and prevents dissolution and corrosion of the surface of the barrier layer 52 by hydrogen fluoride generated by the reaction of the electrolyte and moisture, particularly the 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. In addition, it improves the adhesiveness (wettability) of the surface of the barrier layer 52, and shows the effect of preventing delamination between the base material layer 51 and the barrier layer 52 during heat sealing and preventing delamination between the base material layer 51 and the barrier layer 52 during molding.

[0029] The heat-sealable resin layer 53 is joined to the barrier layer 52, for example, via the adhesive layer 55. The heat-sealable resin layer 53 contained in the outer packaging film 50 is a layer that imparts sealing properties to the outer packaging film 50 by heat sealing. Examples of the heat-sealable resin layer 53 include resin films made of polyester resins such as polyethylene terephthalate-based resins and polybutylene terephthalate-based resins, polyolefin resins such as polyethylene-based resins and polypropylene-based resins, cyclic polyolefin resins, or acid-modified polyolefin resins obtained by graft-modifying these polyolefin resins with an acid such as maleic anhydride. From the viewpoints of sealing properties and strength, the thickness of the heat-sealable resin layer 53 is preferably, for example, 20 to 300 μm, and more preferably 40 to 150 μm.

[0030] The outer packaging film 50 preferably has one or more layers having a buffering 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 outside the base material layer 51, or the base material layer 51 may also serve as the buffer layer. When the outer packaging film 50 has a plurality of buffer layers, the plurality of buffer layers may be adjacent to each other, or may be laminated via the base material layer 51 or the barrier layer 52 or the like.

[0031] The material constituting the buffer layer can be arbitrarily selected from materials having cushioning properties. Materials having cushioning properties are, for example, rubber, non-woven fabric, or foamed 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 non-woven fabric is preferably a material having excellent heat resistance. When the buffer layer is constituted by a non-woven fabric, the lower limit value of the thickness of the buffer layer is preferably 100 μm, more preferably 200 μm, still more preferably 1000 μm. When the buffer layer is constituted by a non-woven fabric, the upper limit value of the thickness of the buffer layer is preferably 5000 μm, more preferably 3000 μm. The preferable range of the thickness of the buffer layer is 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 range of the thickness of the buffer layer is most preferably 1000 μm to 3000 μm.

[0032] When the buffer layer is constituted by rubber, the lower limit value of the thickness of the buffer layer is preferably 0.5 mm. When the buffer layer is constituted by rubber, the upper limit value of the thickness of the buffer layer is preferably 10 mm, more preferably 5 mm, still more preferably 2 mm. When the buffer layer is constituted by rubber, the preferable 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, since the buffer layer functions as a cushion, it is possible to suppress the exterior film 50 from being damaged by the impact when the power storage device 10 falls or by the handling during the manufacture of the power storage device 10.

[0034] In this embodiment, with the outer film 50 wound around the electrode body 20 and the lid body 60, the heat-sealable resin layers 53 on the mutually facing surfaces of the outer film 50 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 outer body 40. In the outer body 40, the position where the first sealing portion 70 is formed can be arbitrarily selected. In this embodiment, the base 70X of the first sealing portion 70 is located on the side 45 at the boundary between the first surface 41 and the second surface 42 of the outer body 40. The area of the first surface 41 is larger than that of the second surface 42. The base 70X of the first sealing portion 70 may be located on any surface of the outer body 40. In this embodiment, the first sealing portion 70 is, for example, folded toward the second surface 42 of the outer body 40. The first sealing portion 70 may protrude outward from the electrode body 20 in a plan view, or may be folded toward the first surface 41. In the outer 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 the 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 body] FIG. 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 power storage device 10. The lid body 60 is, for example, made of resin. The lid body 60 may be formed by cold-forming the outer film 50, for example. Alternatively, the lid body 60 may be a metal formed product. Further, the material constituting the lid body 60 may contain at least one 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 on the side 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 the 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 (in this embodiment, the LR direction) in a front view of the lid body 60. In this embodiment, the second surface 62, which is the surface facing outward in the power storage device 10, is taken as the front 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 (in this embodiment, the UD direction) that intersects the first direction in a front view of the lid body 60. In this embodiment, in a front view of the lid body 60, the first direction and the second direction are orthogonal. The first direction and the second direction do not have to be orthogonal in a front view of the lid body 60. The fourth seal surface 63D constitutes the lower surface of the lid body 60. The fourth seal surface 63D extends in a first direction (in this embodiment, the LR direction) in a front view of the lid body 60.

[0038] When the lid body 60 is plate-shaped, even when the power storage devices 10 are stacked, it is preferable that the lid body 60 has a certain thickness so that the exterior body 40 is suppressed from deforming. From another perspective, when the lid body 60 is plate-shaped, when forming the second sealing portion 80, it is preferable that the lid seal portion 63 of the lid body 60 has a certain thickness so that the lid seal portion 63 of the lid body 60 and the exterior film 50 can be suitably heat-sealed. 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 preferable range of the thickness of the material constituting the lid body 60 is 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, 4.0 mm to 12 mm. In the present embodiment, when the lid body 60 is described as plate-shaped, an aspect in which the lid body 60 is constituted only by a film defined by the [Packaging Terms] standard of JIS (Japanese Industrial Standards) is not included. Note that 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, 67. The boundary 64 is the boundary between the first seal surface 63A and the second seal surface 63B. The boundary 65 is the boundary between the first seal surface 63A and the third seal surface 63C. The boundary 66 is the boundary between the fourth seal surface 63D and the second seal surface 63B. The boundary 67 is the boundary between the fourth seal surface 63D and the third seal surface 63C. The shapes of the boundaries 64 to 67 may be corners, or may be rounded by R processing. In the present embodiment, the boundaries 64 to 67 are corners.

[0040] From the viewpoint of suitably heat-sealing the lid body 60 and the exterior film 50, it is preferable that the material constituting the lid body 60 and the material constituting the heat-sealable resin layer 53 of the exterior film 50 have the same main material. In the present embodiment, the material constituting the lid body 60 and the material constituting the heat-sealable resin layer 53 are mainly made of polypropylene. Here, the main material means, for example, 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 amount of the materials contained in the component is 100% by mass.

[0041] In the present embodiment, a through hole 60X into which an electrode terminal 30 described later is inserted is formed in the lid body 60. The through hole 60X penetrates the first surface 61 and the second surface 62. In a state where the electrode body 20 is housed, 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 slight gap between the through hole 60X of the lid body 60 and the electrode terminal 30 is filled with, for example, resin. In the power storage device 10, the position where the electrode terminal 30 protrudes to the outside can be arbitrarily selected. For example, the electrode terminal 30 may protrude to the outside through a hole formed in any one of the six surfaces of the exterior body 40. In this case, a slight gap between the exterior body 40 and the electrode terminal 30 is filled with, for example, resin. In the power 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 integrally formed. In addition, when the electrode terminal 30 does not protrude from the edge of the exterior body 40, the through hole 60X may not be formed in the lid body 60.

[0042] [Electrode Terminal] Referring back to FIG. 1, the power storage device 10 according to the present embodiment includes a pair of electrode terminals 30. The electrode terminals 30 are metal terminals used for power input and output 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 the edge of the outer package 40, for example. Note that the electrode terminal 30 only needs to be capable of power input and output of the electrode body 20, and for example, it does not necessarily have to protrude from the outer package 40. When the lid 60 described later is made of, for example, metal, the lid 60 may also serve as the function of the electrode terminal 30. In this case, the lid 60 having the function as an electrode terminal may or may not protrude from the outer package 40.

[0043] The metal material constituting the electrode terminal 30 is, for example, aluminum, nickel, copper, or the like. For example, when the electrode body 20 is a lithium-ion battery, the electrode terminal 30 connected to the current collector tab as the positive electrode is usually made of aluminum or the like, and the electrode terminal 30 connected to the current collector tab 210 as the negative electrode is usually made of copper, nickel, or the like.

[0044] [Protection member] Referring back to FIG. 1, the power storage device 10 further includes a protection member 90 and a protection member 91. The protection member 90 and the protection member 91 are respectively disposed outside the corner portion 230 and the ridge line portions 20A to 20D of the electrode body 20 so as to cover the corner portion 230 and the ridge line portions 20A to 20D. In the first embodiment, the protection member 90 and the protection member 91 are respectively disposed outside the outer package 40 and joined to the outermost layer of the outer packaging film 50 or the lid 60.

[0045] FIG. 5 is a perspective view showing the configuration of the protective member 90. The protective member 90 is a member disposed outside the ridge line 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 that intersects the first surface portion 900. Thus, in the present 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. Thereby, the protective member 90 strengthens the portions corresponding to the ridge line portions 20B to 20C of the electrode body 20 in the exterior body 40. Note that the protective member 90 may be a simple plate-like member having no L shape before being disposed on the exterior body 40, or may have the shape as shown in FIG. 5 after being joined to the exterior body 40.

[0046] In this embodiment, the protective member 91 is a member disposed outside 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 in the UD direction. The protective member 91 is also joined to the outermost layer of the exterior film 50, similar to the protective member 90. The protective member 91 is preferably disposed outside the ridge portion 20A and on the base 70X of the first sealing portion 70. Since the overhanging portion 50X is movable relative to other parts of the exterior body 40, the portion of the overhanging portion 50X, particularly the portion including the base 70X of the first sealing portion 70, is prone to material fatigue. In the portion of the exterior film 50 where material fatigue occurs, the barrier layer 52 may peel off from the base material layer 51 and the heat-sealable resin layer 53, cracks may occur, and the exterior film 50 may be damaged. In a typical example, the power storage device 10 may be moved to an arbitrary location while the overhanging portion 50X (the first sealing portion 70) is being held. In such a case, since the overhanging portion 50X is movable relative to other parts of the exterior body 40, the portion of the exterior film 50 including the base of the overhanging portion 50X, in other words, the portion including the base 70X of the first sealing portion 70, may be damaged, and the sealing performance of the power storage device 10 may be reduced. By disposing the protective member 91 on the base 70X of the first sealing portion 70, the movement of the overhanging portion 50X can be suppressed, and the periphery of the base 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. In addition to or instead of this, the protective member 91 may be disposed on the 2nd 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 follow the 2nd surface 42 of the exterior body 40 and the lower surface of the overhanging portion 50X, respectively. Further, with the overhanging portion 50X folded toward the first surface 41, the protective member 90 may be disposed outside the ridge portion 20A so as to span the base 70X of the overhanging portion 50X (the first sealing portion 70) folded from the second surface 42. Furthermore, with the overhanging portion 50X folded toward the second surface 42, the protective member 90 may be disposed outside the ridge portion 20A so as to span the base 70X of the overhanging portion 50X (the first sealing portion 70) folded from the first surface 41.

[0047] The materials forming the protective members 90 and 91 may include at least one of resin, metal, metal oxide, carbon material (such as carbon fiber reinforced plastic), and rubber material. 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. Further, the materials forming the protective members 90 and 91 are preferably materials that can be elastically deformed. In the power storage device 10, the internal pressure of the power storage device 10 may increase due to volume changes of the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charge and discharge, and the generation of gas. When the internal pressure of the power storage device 10 increases, the exterior body 40 may expand and the exterior film 50 may stretch. Further, in the manufacturing process of the power storage device 10, when vacuum pumping is performed, the exterior body 40 may contract. When the protective members 90 and 91 are formed of a material that can be elastically deformed, the protective members 90 and 91 can be deformed corresponding to such expansion and contraction of the exterior body 40, and it becomes difficult to separate from the exterior film 50, so the effects described later can be further enhanced. Further, when the electrode body 20 has an electrolytic solution, the surfaces of the protective members 90 and 91 are preferably made of a material having resistance to the electrolytic solution.

[0048] On the other hand, when the protective members 90 and 91 are formed of a material having relatively low stretchability and shrinkability, the protective members 90 and 91 have an incidental effect of suppressing the expansion and contraction deformation of the exterior body 40 described above. Specifically, the presence of the protective members 90 and 91 having relatively low stretchability and shrinkability outside the exterior film 50 can limit the above expansion of the exterior body 40. Further, when the protective members 90 and 91 are at least partially joined to the exterior film 50, the stretchability of the exterior film 50 in that portion is reduced, so that the above contraction of the exterior body 40 can be limited.

[0049] The method of joining the protective members 90 and 91 to the exterior film 50 is not particularly limited. For example, a method of interposing an adhesive between the protective members 90 and 91 and the exterior body 40, a method of fusing with a heat-fusible resin between the protective members 90 and 91 and the exterior body 40, a method of interposing a tape having adhesive layers on both sides between the protective members 90 and 91 and the exterior body 40, a method of configuring at least one of the protective members 90 and 91 in a tape shape having an adhesive layer on one side and attaching it along the ridge line of the power storage device, etc. may be mentioned.

[0050] <1-2. Action and effect of the power storage device> The ridge line portions 20A to 20D and the corner portion 230 of the electrode body 20 have a sharper shape than other portions of the electrode body 20, and when an impact is applied to the power storage device 10, the exterior film 50 is likely to be damaged by coming into contact with the exterior film 50. According to the power storage device 10, the protective members 90 and 91 cover the portions of the exterior body 40 corresponding to the ridge line portions 20A to 20D and the corner portion 230 of the electrode body 20. Thereby, even if an impact is applied to the power storage device 10, the exterior film 50 is reinforced at the portions corresponding to the ridge line portions 20A to 20D and the corner portion 230 of the electrode body 20, and it is possible to suppress the exterior film 50 from being damaged by the ridge line portions 20A to 20D and the corner portion 230 of the electrode body 20. As a result, the durability of the power storage device 10 is improved.

[0051] [2. Second Embodiment] The power storage device 10A of the second embodiment is different from the first embodiment in that it includes a protective member 92 instead of the protective members 90 and 91, and the other configurations are the same as those of the first embodiment. Hereinafter, the power storage device 10A of the second embodiment will be described centering on the differences from the first embodiment.

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

[0053] Each of the first parts 920 extends in the FB direction and has an L shape when viewed from the FB direction. Both end portions of the first part 920 in the FB direction are connected to the third part 922.

[0054] The second part 921 extends in the FB direction and has a flat plate shape when viewed from the UD direction. Both end portions 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 line portion 20A and on the base 70X of the first sealing portion 70. This is for the reason 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 surface portion 9220 facing the second surface 62 of the lid body 60, and a side wall portion 9221 that stands up from the periphery of the wall surface portion 9220 and covers at least a part of the lid seal portion 63 from the outside of the outer film 50. That is, in the present embodiment, the third part 922 is formed in a substantially container shape. Note that in FIG. 7, for convenience of explanation, illustration of other elements that can be formed in the third part 922, such as through holes and slits, is omitted.

[0056] The third part 922 may have a function of reinforcing the seal of the second sealing portion 80 by covering together the lid seal portion 63 of the lid body 60, the portion of the exterior film 50 facing the lid seal portion 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 to include a material that does not allow gas or moisture to permeate, or is formed to include a layer that does not allow gas or moisture to permeate. When heat-sealing the lid seal portion 63 with the heat-fusible resin layer 53 of the exterior film 50, if the length of the exterior film 50 is greater than the length of the lid seal portion 63, sagging may occur in the exterior film 50, and the second sealing portion 80 may not be partially formed. When such a sealing defect occurs, at least one of gas and moisture may enter the exterior body 40, or if the power storage device 10 has an electrolytic solution, the electrolytic solution may leak to the outside of the exterior body 40. When the third part 922 covers both the lid seal portion 63 and the exterior film 50 and reinforces the seal by the second sealing portion 80, even if a sealing defect occurs in the second sealing portion 80, it is possible to suppress at least one of gas and moisture from entering the exterior body 40 or the electrolytic solution from leaking to the outside of the exterior body 40. That is, the space between the exterior film 50 and the lid body 60 can be more reliably sealed.

[0057] Furthermore, when the third part 922 is formed in the above-described 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 part 63). The curable resin is a resin containing 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 contain at least one of a photocurable resin and a room-temperature curable resin. A photocurable resin is a resin that cures when irradiated with light of a specific wavelength. Examples of photocurable resins include radical polymerization resins that cure by radical chain reaction with functional groups of monomers or oligomers when irradiated with ultraviolet light, and cationic polymerization resins that initiate a cationic polymerization reaction and cure when irradiated with ultraviolet light. Examples of radical polymerization resins include acrylic resins, and examples of cationic polymerization resins include epoxy resins and vinyl ethers. Examples of room-temperature curable resins include resins mainly composed of epoxy resins, ester resins, or acrylic resins that cure when mixed with a curing agent. Examples of thermosetting resins include phenol resins, epoxy resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, silicone resins, polyurethanes, thermosetting polyimides, and the like. Examples of electron beam curable resins include acrylic resins. By filling the space between the lid body 60 and the third part 922 with these curable resins, even if a sealing defect occurs in the second sealing part 80, it is possible to more reliably prevent gas, moisture, or electrolyte from leaking outside the power storage device 10A from entering through the sealing defect part.

[0058] The connection method between the first part 920, the second part 921 and the third part 922 is not particularly limited. For example, among the first part 920 and the third part 922, an engaging portion can be formed on one of them, and an engaged portion can be formed on the other, and the first part 920 and the third part 922 can be connected by engaging them. Similarly, for example, among the second part 921 and the third part 922, an engaging portion can be formed on one of them, and an engaged portion can be formed on the other, and the second part 921 and the third part 922 can be connected by engaging them. The engaging portion is, for example, a convex portion, and the engaged portion is, for example, a concave portion capable of fitting and fixing the convex portion. 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 by a heat-fusible resin. The first part 920 to the third part 922 may be attached to the outer package 40 that seals the electrode body 20 after being connected, or may be attached to and connected to the outer package 40 that seals the electrode body 20 at the same time. Also, the first part 920, the second part 921, and the third part 922 may be integrally formed. In this case, the protective member 92 is preferably formed of a deformable material so as to enable attachment to the outer package 40.

[0059] The first part 920 to the third part 922 can each be formed of a material similar to the material forming the protection members 90 and 91. The materials forming each part may be different for each part or the same. Also, the method of joining the first part 920 to the second part 921 to the exterior film 50 is not particularly limited. For example, similar to the protection members 90 and 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 heat-sealing between the first part 920 to the second part 921 and the exterior body 40 with a heat-sealable resin, a method of interposing a tape having adhesive layers on both sides between the first part 920 to the second part 921 and the exterior body 40, a method of configuring at least one of the first part 920 to the second part 921 in a tape shape having an adhesive layer on one side and attaching this along the ridge lines of the power storage device, etc. can be mentioned. Regarding the third part 922 as well, in addition to or instead of the methods already described, it can be joined to the lid body 60 and the exterior film 50 in the same manner as the first part 920 to the second part 921.

[0060] <2-2. Action and Effect of Power Storage Device> According to the power storage device 10A of the second embodiment, the same effects as the power storage device 10 according to the first embodiment can be achieved. 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 changes in the internal pressure of the power storage device 10A, etc., and it becomes difficult to separate from the exterior film 50. Thereby, even if an impact is applied to the power storage device 10A, the exterior film 50 is reinforced at the portions corresponding to the ridge line portions 20A to 20D and the corner portion 230 of the electrode body 20, and it is possible to suppress the exterior film 50 from being damaged by the ridge line portions 20A to 20D and the corner portion 230 of the electrode body 20. Further, when the third part 922 is formed so as to reinforce the seal 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. Thereby, the space between the exterior film 50 and the lid body 60 can be sealed more reliably.

[0061] When the first part 920 to the third part 922 are formed of a material with relatively low stretchability and deformability, the protective member 92 has an incidental effect of suppressing the stretchability and deformability of the exterior body 40 described above. In the power storage device 10A, due to the volume change of the positive electrode active material and the negative electrode active material of the electrode body 20 accompanying charge and discharge, and the generation of gas, etc., the internal pressure of the power storage device 10A may increase. When the internal pressure of the power storage device 10A increases, the exterior body 40 may expand. Since the protective member 92 with relatively low stretchability and deformability exists outside the exterior film 50, the above expansion of the exterior body 40 can be limited. Also, in the manufacturing process of the power storage device 10A, when vacuum pumping is performed, the exterior body 40 may contract. When the protective member 92 is at least partially joined to the exterior film 50, it reduces the stretchability of the exterior film 50 at that part, thereby suppressing the stretchability and deformability of the exterior body 40.

[0062] [3. Third Embodiment] The power 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, and other configurations are the same as those of the first embodiment. Hereinafter, the power storage device 10B of the third embodiment will be described centering on the parts different from the first embodiment.

[0063] [3-1. Configuration of Power Storage Device] FIG. 8 is a perspective view showing the configuration of the power storage device 10B of the third embodiment (however, the illustration of the electrode terminal 30 is omitted). In the power storage device 10B, the protective member 93 is disposed between the electrode body 20 and the exterior body 40. That is, the protective member 93 is sealed inside the exterior body 40 together with the electrode body 20.

[0064] FIG. 9 is a perspective view showing the configuration of the electrode body 20 and the protective member 93 of the power storage device 10B. The protective member 93 has two side wall portions 930 facing the front surface 21 and the back surface 22 of the electrode body 20, and four frame portions 931 connecting these between the two side wall portions 930. The side wall portions 930 are plate-like members arranged at intervals in the FB direction, respectively. The frame portions 931 are columnar members extending in the FB direction and connected to the two side wall portions 930, respectively. The electrode body 20 can be disposed in the space defined by the side wall portions 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 respectively disposed outside the ridge line portions 20A to 20D of the electrode body 20, preventing the corner portions 230 and the ridge line 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 line portions 20A to 20D and the exterior film 50. As long as the corner portions 230 and the ridge line 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, L-shaped, rectangular, circular, semi-circular, polygonal, etc. The frame portions 931 are at the outermost positions in the protective member 93 and can contact the exterior film 50. Therefore, at least the portions of the frame portions 931 that may contact the exterior film 50 are preferably rounded so as not to damage the exterior film 50.

[0066] The side wall portions 930 are arranged such that one 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 disposed inside the protective member 93, the two side wall portions 930 are respectively disposed outside the ridge line portions 20A to 20D of the electrode body 20, preventing the corner portions 230 and the ridge line portions 20A to 20D from contacting the exterior film 50. That is, the side wall portions 930 function as a buffer between the corner portions 230 and the ridge line portions 20A to 20D and the exterior film 50. For this reason, at least the portions of the side wall portions 930 that may come into contact with the exterior film 50 are preferably rounded so as not to damage the exterior film 50. For example, although the side wall portions 930 have a substantially rectangular shape when viewed in the FB direction, it is preferable that the portions corresponding to the vertices of the rectangle are rounded.

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

[0068] Examples of the material for forming the side wall portions 930 and the frame portions 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. Further, the material for forming the side wall portions 930 and the frame portions 931 is preferably a material that can be elastically deformed. When the side wall portions 930 and the frame portions 931 are formed of an elastically deformable material, the protective member 93 can deform in response to the volume change of the positive and negative active materials of the electrode body 20 accompanying charge and discharge, and the effects described later can be further enhanced. Furthermore, when the electrode body 20 has an electrolytic solution, the surfaces of the side wall portions 930 and the frame portions 931 are preferably made of a material resistant to the electrolytic solution. Note that the materials for forming the side wall portions 930 and the frame portions 931 may be different from each other or the same.

[0069] On the other hand, when the side wall portion 930 and the frame portion 931 are formed of a material with relatively low stretchability and are at least partially joined to the innermost layer of the exterior film 50, the protective member 93 has an incidental effect of suppressing the expansion and contraction deformation of the exterior body 40. In the power storage device 10B, due to the volume change of the positive and negative electrode active materials of the electrode body 20 accompanying charge and discharge, and the generation of gas, etc., the internal pressure of the power storage device 10B may increase. When the internal pressure of the power storage device 10B increases, the exterior body 40 may expand. Also, in the manufacturing process of the power storage device 10B, when vacuum pumping is performed, the exterior body 40 may contract. The protective member 93 is at least partially joined to the exterior film 50, thereby reducing the stretchability of the exterior film 50 in that portion, and thus the expansion and contraction deformation of the exterior body 40 can be made limited.

[0070] <3-2. Action and Effect of Power Storage Device> According to the power storage device 10B of the third embodiment, the protective member 93 functions as a cushioning material that prevents contact between the ridge line portions 20A to 20D and the corner portion 230 of the electrode body 20 and the exterior film 50. For this reason, in the electrode body 20, particularly sharp portions are prevented from impacting the exterior film 50 and damaging the exterior film 50. Furthermore, when the protective member 93 itself is formed of an elastic material or when the portion in contact with the exterior film 50 is rounded, the damage to the exterior film 50 can be more reliably prevented. Also, the protective member 93 protects the electrode body 20 against impacts applied from the outside of the power storage device 10B. As a result, the durability of the power storage device 10B is improved.

[0071] [4. Fourth Embodiment] The power 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 includes the lid body 60, and other configurations are the same as those of the third embodiment. Hereinafter, the power storage device 10C of the fourth embodiment will be described focusing on the differences from the third embodiment.

[0072] <4-1. Configuration of the energy storage device> FIG. 10 is a perspective view showing the configuration of the energy storage device 10C according to the fourth embodiment (however, illustration of the electrode terminals 30 is omitted). The protective member 94 includes a pair of lid bodies 60 and four frame portions 940 that connect the pair of lid bodies 60 therebetween. The configuration of the lid body 60 is common to the configuration of the lid body 60 according to the first to third embodiments. Further, 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 its configuration is common to the frame portion 931 of the third embodiment. The electrode body 20 can be disposed in the space defined by the lid body 60 and the frame portion 940.

[0073] <4-2. Operation and effects of the energy storage device> According to the energy storage device 10C of the fourth embodiment, the same effects as those of the energy storage device 10B according to the third embodiment can be achieved. Further, according to the energy storage device 10C of the fourth embodiment, the pair of lid bodies 60 also serve as a part of the protective member 94. Thereby, the protective member 94 can be configured without excessively increasing the number of parts.

[0074] [5. Modifications] The above-described embodiments are examples of forms that the energy storage device according to the present invention can take, and are not intended to limit the form. The energy storage device according to the present invention can take a form different from the forms illustrated in the embodiments. An example thereof is a form in which a part of the configuration of each embodiment is replaced, changed, or omitted, or a form in which a new configuration is added to each embodiment. Some examples of modifications of each embodiment are shown below. Note that the above-described embodiments and the following modifications can be combined with each other as long as they do not technically conflict with each other.

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

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

[0077] (3) In the power storage devices 10, 10A to 10C of the first to fourth embodiments, the exterior film 50 may project outward from the lid body 60 in the FB direction. The part of the exterior film 50 that projects beyond the lid body 60 may be folded like a gable-top type pouch or a brick type pouch. The part of the exterior film 50 that projects beyond the lid body 60 may be bent along the second surface 62 of the lid body 60.

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

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

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

[0081] (7) When the protective members 90 to 94 of the first to fourth embodiments have the function of suppressing the deformation of the above-described exterior body 40, the protective members 90 to 94 may be configured to focus on suppressing the deformation of a specific surface of the exterior body 4 according to the usage mode of the power storage devices 10, 10A to 10C. The power storage devices 10, 10A to 10C are arranged and used such that, for example, as shown in FIG. 11, the fourth surfaces 44 of the plurality of 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 surface 44 is in contact with the cooling mechanism 200, and the third surface 43 is in direct contact with the first surface 41 of the adjacent power storage devices 10, 10A to 10C, or is in indirect contact via a plate-like member, a cushioning material, or the like. Therefore, for example, when considering the expansion as one aspect of the deformation of the exterior body 40, in the power storage devices 10, 10A to 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 difficult to expand even when the internal pressure of the power storage devices 10, 10A to 10C increases.

[0082] On the other hand, since the second surface 42 of the exterior body 40 is not in contact with other elements such as the power storage devices 10, 10A to 10C, it is likely to expand when the internal pressure of the power storage devices 10, 10A to 10C increases. Therefore, in the power 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 so as to suppress the expansion of the second surface 42. On the other hand, in the power storage devices 10B, 10C, the expansion of the second surface 42 can be suppressed by joining, for example, a portion of the side wall portion 930, the frame portion 931, the frame portion 940, or the lid body 60 that exists on the back side of the second surface 42 to the innermost layer of the exterior film 5 facing the portion. 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 is the same not only for the expansion of the exterior body 40 but also for the contraction.

Explanation of Reference Numerals

[0083] 10, 10A, 10B, 10C: Storage device 20: Electrode body 20A - 20D: Ridge part 30: Electrode terminal 40: Exterior body 40A: Opening 50: Exterior film 60: Cover body 90 - 94: Protection member 230: Corner part

Claims

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

2. Further, a second protective member is provided on the outer side of the exterior film along at least one of the ridge lines. The power storage device according to claim 1 .

3. The first protective member further includes a side wall portion connected to the frame portion disposed apart from the stacking direction. The electricity storage device according to claim 1 or 2.

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

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

6. The side wall portion is formed with a through hole 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. An electrode body having an upper surface and a lower surface and a three-dimensional shape including ridge portions 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, 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. Energy storage device.

10. A protective member for use in an electricity storage device, The power storage device is an electrode body having an upper surface and a lower surface and a three-dimensional shape including ridges spaced apart in a stacking 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 inner side of the exterior film and spaced apart in the stacking direction along each of the ridge line portions spaced apart in the stacking direction; Protective material.

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

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