Electricity storage device

Abstract

The present disclosure provides a power storage device in which an electrode body can be efficiently permeated by an electrolyte solution. A power storage device disclosed herein is provided with: a case having a liquid injection part; an electrode body; a resin film disposed so as to surround the electrode body; and an electrolyte solution. The shell comprises a bottom wall, an upper wall and a first side wall. The liquid injection part is arranged at the position, close to the upper wall, of the first side wall. The electrode body is disposed such that the bottom faces the bottom wall. The resin film has: a first end portion extending from one side in a predetermined direction so as to cover a part of the bottom portion of the electrode body; and a second end portion extending in the predetermined direction from a direction opposite to the first end portion and extending so as to cover a part of the bottom portion of the electrode body. A portion of the second end portion overlaps a bottom wall side of the housing with respect to the first end portion.

Description

Technical Field

[0001] This disclosure relates to energy storage devices. Background Technology

[0002] Japanese Patent Application Publication No. 2007-42628 discloses a secondary battery having an electrode assembly in a jelly roll configuration. This secondary battery has a structure with a positive terminal at one end of the casing and a negative terminal at the opposite end.

[0003] Japanese Patent Application Publication No. 2019-29218 discloses an insulating support for housing an electrode. The insulating support has a structure that covers the bottom surface of the electrode.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2007-42628

[0007] Patent Document 2: Japanese Patent Application Publication No. 2019-29218 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Additionally, the manufacturing method of the energy storage device may include an impregnation process in which an electrolyte is impregnated with the electrode body inside the casing. During the impregnation process, it is necessary to ensure that the electrolyte efficiently penetrates the electrode body. However, when the electrode body is surrounded by an insulating support, it can sometimes be difficult for the electrolyte to penetrate the electrode body.

[0010] Solution for solving the problem

[0011] One aspect of the technology disclosed herein is an energy storage device comprising: a housing having a liquid injection portion; an electrode body housed within the housing; a resin film disposed between the housing and the electrode body in a manner surrounding the electrode body; and an electrolyte housed within the housing. The housing includes: a bottom wall; an upper wall facing the bottom wall; and a first side wall extending from the edge of the bottom wall to the edge of the upper wall. The liquid injection portion is disposed on the first side wall at a position closer to the upper wall than the bottom wall. The electrode body is configured such that its bottom faces the bottom wall. The resin film has: a first end extending in a predetermined direction from one side in a manner covering a portion of the bottom of the electrode body; and a second end extending in the predetermined direction from a direction opposite to the first end in a manner covering a portion of the bottom of the electrode body. A portion of the second end overlaps with the bottom wall side of the housing relative to the first end.

[0012] The aforementioned energy storage device enables the electrolyte to efficiently permeate the electrode body. Attached Figure Description

[0013] Figure 1 This is a perspective view of an embodiment of an energy storage device.

[0014] Figure 2 Therefore with Figure 1 A perspective view of the energy storage device in one embodiment from different viewpoints.

[0015] Figure 3 It is a schematic representation Figure 1 A cross-sectional view of the internal structure of an energy storage device.

[0016] Figure 4 This is a cross-sectional view schematically illustrating the structure of an electrode body according to one embodiment.

[0017] Figure 5 From and Figure 3 Different perspectives are used to illustrate the meaning. Figure 1 A cross-sectional view of the internal structure of an energy storage device.

[0018] Figure 6 It is a cross-sectional view schematically showing the structure of the area between the electrode body and the bottom wall. Detailed Implementation

[0019] Hereinafter, some embodiments of the technology disclosed herein will be described in detail with reference to the accompanying drawings. Matters necessary for implementation other than those specifically mentioned in this specification (e.g., the general structure and manufacturing process of energy storage devices that do not characterize this disclosure) can be understood by those skilled in the art based on prior art. This disclosure can be implemented based on the content disclosed in this specification and common technical knowledge in the field. Furthermore, in the following drawings, components and parts that perform the same function are labeled with the same reference numerals. Additionally, the dimensional relationships (length, width, thickness, etc.) in the drawings do not necessarily reflect actual dimensional relationships.

[0020] In this specification, "energy storage device" is a concept that includes a device in which a charging and discharging reaction occurs by the movement of a charge carrier between a pair of electrodes (positive and negative electrodes). That is, energy storage devices include batteries such as secondary batteries (e.g., lithium-ion secondary batteries, nickel-metal hydride batteries, nickel-cadmium batteries) and capacitors such as lithium-ion capacitors and double-layer capacitors (physical batteries).

[0021] In this specification, "cylindrical" refers to a cylindrical shape in which the opening in a cross-section orthogonal to the axial direction is a polygon (e.g., a quadrilateral). Furthermore, the corners where the sides of the polygon meet may also be rounded.

[0022] In this specification, "approximately rectangular" is a term that includes not only a complete rectangle (rectangle) but also shapes such as those where the corners of the long and short sides of a rectangle are connected to form rounded corners, or shapes with cuts at the corners.

[0023] <Electronic Storage Devices>

[0024] Hereinafter, the energy storage device 1 will be described as one embodiment. Figure 1 This is a perspective view schematically illustrating one embodiment of an energy storage device. Figure 2 Therefore with Figure 1 A perspective view of the energy storage device in one embodiment from different viewpoints. Figure 3 It is a schematic representation Figure 1 A cross-sectional view of the internal structure of the energy storage device. In this specification, the reference numerals X, Y, and Z in the drawings are referred to as the first direction, the second direction, and the third direction, respectively. Additionally, X1, X2, Y1, Y2, Z1, and Z2 in the drawings are corresponding reference numerals used to indicate the directions of each drawing. However, these directions are determined for ease of explanation and do not limit the arrangement of the energy storage device.

[0025] like Figures 1-3 As shown, the energy storage device 1 includes a housing 10, a positive terminal 22, a negative terminal 24, an electrode body 30, a first spacer 42, a second spacer 44, a resin film 50, and an electrolyte (not shown). The housing 10 has an injection section 19 for injecting the electrolyte into its interior. Here, the energy storage device 1 is a lithium-ion secondary battery. The various structures will be described below.

[0026] (1) Shell

[0027] like Figures 1-2 As shown, the housing 10 includes a bottom wall 11, an upper wall 12, and a first side wall 17. In this embodiment, the housing 10 includes a housing body 10A, a first cover 10B, and a second cover 10C. The housing body 10A includes a bottom wall 11, an upper wall 12, a first wide side wall 13, and a second wide side wall 14. The first cover 10B is configured as the first side wall 17. The housing 10 is configured such that when the electrode body 30 is immersed in electrolyte, the bottom wall 11 is located at a position lower than the upper wall 12 in the vertical direction.

[0028] The main body 10A of the housing is at one end in the first direction X ( Figure 1 The X1 side has a first opening 15 and at the other end ( Figure 1 A cylindrical member with a second opening 16 on the X2 side. The bottom wall 11 and the top wall 12 face each other in the third direction Z. The bottom wall 11 and the top wall 12 are each formed as plates. The bottom wall 11 and the top wall 12 are each approximately rectangular when viewed from above. The bottom wall 11 and the top wall 12 each have a long side extending along the first direction X.

[0029] The first wide sidewall 13 and the second wide sidewall 14 face each other in the second direction Y. The first wide sidewall 13 and the second wide sidewall 14 have areas larger than the bottom wall 11 and the top wall 12. The first wide sidewall 13 extends from the edge (long side) 11a of the bottom wall 11 to the edge (long side) 12a of the top wall 12. The second wide sidewall 14 extends from the edge (long side) 11b of the bottom wall 11 to the edge (long side) 12b of the top wall 12. The first wide sidewall 13 and the second wide sidewall 14 are each formed in a plate shape. The first wide sidewall 13 and the second wide sidewall 14 are each approximately rectangular. The first wide sidewall 13 and the second wide sidewall 14 each have a long side extending along the first direction X.

[0030] The housing body 10A can be manufactured, for example, by bending a metal sheet into a cylindrical shape and joining the seams (e.g., by welding). Therefore, in Figure 1 In the shown housing body 10A, a welded joint 18 extending along the first direction X is formed on the upper wall 12. Furthermore, the housing body 10A can be made of metals such as aluminum, aluminum alloy, iron, or iron alloy. From the viewpoint of ease of processing, the housing body 10A is preferably made of aluminum or an aluminum alloy.

[0031] A safety valve 70 is provided on the bottom wall 11. The safety valve 70 is a thin-walled portion designed to break and release internal pressure when a specified pressure is reached inside the housing 10. In some embodiments, the safety valve 70 may be provided on the upper wall 12 or a side wall instead of the bottom wall 11 of the housing 10. Two or more safety valves 70 may also be provided.

[0032] like Figure 3 As shown, the first sidewall 17 extends from the edge (short side) 11c of the bottom wall 11 to the edge (short side) 12c of the upper wall 12. In this embodiment, a first cover 10B is disposed as the first sidewall 17. The first cover 10B is installed on the first opening 15 and blocks the first opening 15. The first cover 10B is a generally rectangular plate-shaped member. Figure 3 As shown, the first cover 10B extends from the edge (short side) 11c of the bottom wall 11 to the edge (short side) 12c of the upper wall 12. The first cover 10B overlaps with the end faces of the bottom wall 11, upper wall 12, first wide side wall 13, and second wide side wall 14 of the housing body 10A and is joined together. The joining method is not particularly limited; for example, the housing body 10A and the first cover 10B are joined by welding. The material of the first cover 10B is preferably the same metal material as the housing body 10A (aluminum, aluminum alloy, iron, iron alloy, etc.).

[0033] The first cover 10B has a liquid injection section 19. The liquid injection section 19 includes an injection hole 19A and a sealing plug 19B. Figure 3As shown, the injection hole 19A penetrates the first cover 10B, connecting the interior of the housing 10 to the outside. During the manufacture of the energy storage device 1, electrolyte is injected into the interior of the housing 10 through the injection hole 19A. After the electrolyte is injected, the injection hole 19A is sealed by the sealing plug 19B. Thus, the housing 10 is sealed, preventing electrolyte leakage.

[0034] In this embodiment, the liquid injection section 19 is located on the first cover 10B at a position closer to the upper wall 12 than the bottom wall 11. This prevents the electrolyte from leaking out of the injection hole 19A when the electrolyte injected into the housing 10 impregnates the electrode body 30.

[0035] The second cover 10C is installed at the second opening 16, blocking the second opening 16. The second cover 10C is a generally rectangular plate-like member. The second cover 10C faces the first cover 10B. Figure 3 As shown, the second cover 10C extends from the edge (short side) 11d of the bottom wall 11 to the edge (short side) 12d of the upper wall 12. The second cover 10C faces the first cover 10B. The second cover 10C overlaps with the end faces of the bottom wall 11, upper wall 12, first wide side wall 13, and second wide side wall 14 of the housing body 10A and is joined together. The joining method is not particularly limited; for example, the housing body 10A and the second cover 10C are joined by welding. The material of the second cover 10C is preferably the same metal material as the housing body 10A (aluminum, aluminum alloy, iron, iron alloy, etc.). Furthermore, the second cover 10C is an example of a second side wall facing the first side wall 17 of the housing 10.

[0036] (2) Electrode terminals

[0037] The positive terminal 22 is mounted on the first cover 10B. A portion of the positive terminal 22 protrudes outside the housing 10. The positive terminal 22 is preferably made of metal, for example, more preferably aluminum or an aluminum alloy. Figure 3 As shown, the positive terminal 22 is electrically connected inside the housing 10 to the positive electrode plate 32 (more specifically, the positive electrode tab 33 described later) of the electrode body 30 via the positive current collector 23. The positive current collector 23 can be part of the positive terminal 22 or other components made of metal.

[0038] The negative terminal 24 is mounted on the second cover 10C. The negative terminal 24 is positioned on the opposite side of the positive terminal 22 in the first direction X. A portion of the negative terminal 24 protrudes outside the housing 10. The negative terminal 24 is preferably made of metal, more preferably copper or a copper alloy. Figure 3As shown, the negative terminal 24 is electrically connected inside the housing 10 to the negative electrode plate 34 (more specifically, the negative electrode tab 35 described later) of the electrode body 30 via the negative electrode current collector 25. The negative electrode current collector 25 may be part of the negative terminal 24 or may be other components made of metal.

[0039] (3) Electrode body

[0040] Electrode 30 is a power generation element in energy storage device 1. For example... Figure 3 As shown, the electrode body 30 is housed inside the housing 10. Figure 4 This is a cross-sectional view schematically showing the structure of the electrode body 30. Figure 5 From and Figure 3 Different perspectives are used to illustrate the meaning. Figure 1 A cross-sectional view of the internal structure of an energy storage device. Figure 5 The detailed structure of the electrode body 30 is omitted here. The electrode body 30 has a first wide surface 30A, a second wide surface 30B, a bottom 30C, and an upper part 30D. The first wide surface 30A faces the first wide sidewall 13 of the housing 10 inside the housing 10. The second wide surface 30B is the surface facing the first wide surface 30A. The second wide surface 30B faces the second wide sidewall 14 of the housing 10 inside the housing 10. The bottom 30C faces the bottom wall 11 of the housing 10 inside the housing 10. The upper part 30D faces the bottom 30C. The upper part 30D faces the upper wall 12 of the housing 10 inside the housing 10.

[0041] like Figure 4 As shown, the electrode body 30 includes a positive electrode 32, a negative electrode 34, and a separator 36. The positive electrode 32 and the negative electrode 34 are alternately stacked with the separator 36 in between. In this embodiment, the electrode body 30 is stacked along a direction in which the first wide surface 30A and the second wide surface 30B face each other. In this specification, the stacking direction is also referred to as the thickness direction of the electrode body 30.

[0042] In this embodiment, the diaphragm 36 is formed in a zigzag shape (also called a corrugated shape) that is alternately folded at predetermined intervals. In the electrode sheets (positive electrode 32 and negative electrode 34), both sides (layered sides) of the electrode sheets in the thickness direction are held by the folded diaphragm 36. The diaphragm 36 is wound around the outermost peripheral portion of the zigzag structure to form the outer peripheral surface of the electrode body 30. A winding fixing tape 39 is attached to the terminal portion 36e of the diaphragm 36 to prevent slack winding.

[0043] The electrode body 30 has an impregnation region 38 that serves as an inlet for the electrolyte to permeate from the outside of the electrode body 30 to the inside. The impregnation region 38 includes an inflow path 37 that allows the electrolyte to permeate the inter-electrode space (the interior of the electrode body 30) between the positive electrode 32 and the negative electrode 34. In this embodiment, the impregnation region 38 is included on the surface orthogonal to the stacking direction of the electrode plates (positive electrode 32, negative electrode 34). In the impregnation region 38, the end face of the electrode plate (the surface orthogonal to the thickness direction of the electrode plate) can be exposed. In this embodiment, the impregnation region 38 is included on the bottom 30C, the top 30D, the surface facing the first cover 10B, and the surface facing the second cover 10C of the electrode body 30. The bottom 30C, including the impregnation region 38, faces the bottom wall 11 of the housing 10 inside the housing 10. Thus, the electrolyte can permeate into the interior of the electrode body 30 from the bottom wall 11 side of the housing 10.

[0044] The inflow path 37 can be the inlet portion of a connecting hole extending into the interior of the electrode body 30. The diaphragm 36 can be a porous sheet capable of being impregnated with electrolyte. Therefore, in this embodiment, the diaphragm 36 disposed between the positive electrode 32 and the adjacent negative electrode 34 has an inflow path 37.

[0045] In addition, in some embodiments, the inflow path 37 can be a slit or gap disposed on the surface of the diaphragm sheet 36 or the surface of the electrode sheet.

[0046] In addition, Figure 4 In the electrode body 30 shown, a diaphragm 36 is wound around the outermost periphery of the tortuous structure. That is, the bottom 30C, including the impregnation region 38, is covered by the outer peripheral surface of the diaphragm 36. However, the diaphragm 36 has a connecting hole that allows the electrolyte to be impregnated. Therefore, the electrolyte on the outside of the electrode body 30 can reach the impregnation region 38 through the diaphragm 36.

[0047] The positive electrode 32 includes a positive electrode current collector foil and a positive electrode active material layer formed on at least one side of the positive electrode current collector foil. The material of the positive electrode current collector foil is a conductive metallic material. For example, aluminum, aluminum alloys, etc., can be used as the positive electrode current collector foil. Figure 3 As shown, a positive electrode tab 33 extending from the electrode body 30 is provided at the end of the positive electrode current collector foil (X1 side in the figure). The positive electrode tab 33 faces the first cover body 10B. The positive electrode tab 33 has a current collector foil exposure portion. The current collector foil exposure portion is joined to the positive electrode current collector portion 23. The positive electrode active material layer contains a positive electrode active material. The positive electrode active material is a material capable of reversibly attracting and releasing charge carriers. The positive electrode active material can be the same as conventional materials and is not particularly limited. For example, the positive electrode active material can be a lithium transition metal composite oxide such as lithium nickel cobalt manganese composite oxide. The positive electrode active material layer can also contain any component other than the positive electrode active material, such as binders, conductive materials, etc.

[0048] The negative electrode 34 comprises a negative electrode current collector foil and a negative electrode active material layer formed on at least one side of the negative electrode current collector foil. The material of the negative electrode current collector foil is a conductive metallic material. For example, copper or copper alloys can be used as the negative electrode current collector foil. Figure 3 As shown, a negative electrode tab 35 extending from the electrode body 30 is provided at the end of the negative electrode current collector foil (X2 side in the figure). The negative electrode tab 35 faces the second cover 10C. The negative electrode tab 35 has a current collector foil exposure portion. The current collector foil exposure portion is joined to the negative electrode current collector portion 25. The negative electrode active material layer contains a negative electrode active material. The negative electrode active material is a material capable of reversibly adsorbing and releasing charge carriers. The negative electrode active material can be the same as before and is not particularly limited. The negative electrode active material can be, for example, carbon materials such as graphite, silicon materials, etc. The negative electrode active material layer can also contain any component other than the negative electrode active material, such as binders, thickeners, dispersants, etc.

[0049] The diaphragm 36 can be the same as before, without particular limitations. The diaphragm 36 can be a single-layer structure, or a structure with two or more layers, such as a three-layer structure, that have different properties or characteristics (thickness, porosity, etc.). The diaphragm 36 is made of resin, for example, preferably a polyolefin resin. Polyethylene, polypropylene, or mixtures thereof are preferred as the polyolefin resin.

[0050] (4) Electrolyte

[0051] The electrolyte can be the same as before, without any particular restrictions. For example, a non-aqueous electrolyte may contain a non-aqueous solvent (organic solvent) and a supporting salt (electrolyte salt, such as lithium salt or sodium salt). Examples of non-aqueous solvents include carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. Examples of supporting salts include fluorinated lithium salts such as lithium hexafluorophosphate (LiPF6).

[0052] (5) Spacer

[0053] like Figure 3 As shown, a first spacer 42 is disposed between the first cover 10B and the electrode body 30. The first spacer 42 has a bottom side surface 42a facing the bottom wall 11 and an upper side surface 42b facing the upper wall 12. The first spacer 42 has a base 42c extending from the bottom side surface 42a to the upper side surface 42b. The base 42c is configured to cover the surface of the electrode body 30 facing the first cover 10B. The first spacer 42 prevents direct contact between the electrode body 30 and the first cover 10B, thus preventing damage to the electrode body 30.

[0054] The first spacer 42 is preferably made of an insulating resin. Examples of insulating resins include polyamide resin and polyolefin resin (e.g., polypropylene, polyethylene). By making the first spacer 42 insulating, conduction between the electrode body 30 and the first cover 10B can be prevented.

[0055] like Figure 3 As shown, a second spacer 44 is disposed between the second cover 10C and the electrode body 30. The second spacer 44 has a bottom side surface 44a facing the bottom wall 11 and an upper side surface 44b facing the upper wall 12. The second spacer 44 has a base 44c extending from the bottom side surface 44a to the upper side surface 44b. The base 44c is configured to cover the surface of the electrode body 30 facing the second cover 10C. The second spacer 44 prevents direct contact between the electrode body 30 and the second cover 10C, thus preventing damage to the electrode body 30.

[0056] The second spacer 44 is preferably made of an insulating resin. Examples of insulating resins can be the same as those for the first spacer 42 described above.

[0057] (6) Resin film

[0058] like Figure 3 and Figure 5 As shown, the resin film 50 is an insulating member disposed between the housing 10 and the electrode body 30. The resin film 50 is configured to surround the outer periphery of the electrode body 30. In this embodiment, the resin film 50 has a cylindrical shape. The electrode body 30 is housed inside the cylindrical resin film 50. The resin film 50 covers the first wide surface 30A, the second wide surface 30B, the bottom 30C, and the top 30D. This prevents the electrode body 30 from conducting with the housing body 10A.

[0059] In this embodiment, at least a portion of the first spacer 42 and at least a portion of the second spacer 44 are disposed inside the resin film 50. This more effectively prevents the electrode body 30 from communicating with the housing 10.

[0060] In this embodiment, after an electrode body 30 with a first spacer 42 and a second spacer 44 mounted on both sides is disposed on a single film, the film is bent into a cylindrical shape to surround the electrode body 30, the first spacer 42, and the second spacer 44, thereby forming a resin film 50. In some embodiments, the resin film 50 may also be composed of two or more films.

[0061] The resin film 50 can be made of materials such as polyamide resin, polyolefin resin (e.g., polypropylene, polyethylene), etc. Alternatively, the resin film 50 can also be a porous material that can be impregnated with electrolyte.

[0062] Furthermore, the inventors desired to facilitate the penetration of electrolyte accumulated on the bottom side of the casing into the electrode body. The impregnation process, which involves immersing the electrode body in electrolyte, is a particularly time-consuming step in the manufacturing process of energy storage devices. Therefore, if the electrolyte can easily penetrate the electrode body, the manufacturing time of the energy storage device can be shortened.

[0063] Figure 6 This is a schematic cross-sectional view showing the structure of the region between the electrode body 30 and the bottom wall 11. For example... Figure 5 and Figure 6 As shown, the resin film 50 has a first end 52 and a second end 54. The second end 54 and the first end 52 are located between the bottom 30C of the electrode body 30 and the bottom wall 11.

[0064] The first end portion 52 covers a portion of the bottom 30C of the electrode body 30. The first end portion 52 is a portion of the resin film 50 disposed between the bottom 30C of the electrode body 30 and the bottom wall 11 of the housing 10, and refers to the portion extending from one side to the other in a predetermined direction. In this embodiment, the first end portion 52 extends from the second wide surface 30B side (Y1 side) of the electrode body 30 toward the first wide surface 30A side (Y2 side) in the thickness direction (second direction Y) of the electrode body 30.

[0065] The second end portion 54 covers a portion of the bottom 30C of the electrode body 30. The second end portion 54 is a portion of the resin film 50 disposed between the bottom 30C of the electrode body 30 and the bottom wall 11 of the housing 10, meaning the portion extending from one side to the other in a predetermined direction. In this embodiment, the second end portion 54 extends from the first wide surface 30A side (Y2 side) of the electrode body 30 toward the second wide surface 30B side (Y1 side) in the thickness direction (second direction Y) of the electrode body 30.

[0066] The resin film 50 has an overlap portion 56 where at least a portion of a first end 52 overlaps with a portion of a second end 54. In the overlap portion 56, the first end 52 is located on the bottom 30C side of the electrode body 30, and the second end 54 is located on the bottom wall 11 side of the housing 10. In the overlap portion 56, the opposing regions 57 of the first end 52 and the second end 54 are not completely blocked. The opposing regions 57 contain gaps through which electrolyte can pass.

[0067] like Figure 5 and Figure 6As shown, the second end portion 54 includes an electrode body facing portion 60 that faces the bottom 30C of the electrode body 30 without being separated from the first end portion 52. The electrode body facing portion 60 and the overlapping portion 56 are continuously disposed. A first space 62 is formed between the electrode body facing portion 60 and the bottom 30C of the electrode body 30. In this embodiment, the first space 62 is a space created because the thickness of the second end portion 54 is smaller than the thickness of the overlapping portion 56. The first space 62 faces the bottom 30C of the electrode body 30 and communicates with the impregnation region 38.

[0068] In this technology, as described above, the resin film 50 has an overlapping portion 56 where the first end 52 and the second end 54 overlap at the bottom 30C of the electrode body 30. Additionally, there is an electrode body facing portion 60 where the second end 54 faces the electrode body 30 without being separated from the first end 52. A first space 62 exists between the electrode body facing portion 60 and the bottom 30C of the electrode body 30. Since there is no obstruction between the first end 52 and the second end 54 at the second end 54 and the overlapping portion 56, electrolyte can pass through and enter the first space 62. The electrolyte entering the first space 62 permeates the electrode body 30 from the permeation region 38. Therefore, the electrolyte can efficiently permeate the electrode body 30.

[0069] like Figure 6 As shown, the average length L2 of the second end 54 can also be longer than the average length L1 of the first end 52. The average length L1 of the first end 52 and the average length L2 of the second end 54 are the arithmetic mean of their lengths in their respective extending directions. In this embodiment, as... Figure 6 As shown, the average lengths L1 and L2 are the lengths in the thickness direction (second direction Y) of the electrode body 30. Therefore, compared to the case where the average length L1 of the second end 54 is shorter than the average length L2 of the first end 52, the first space 62 is formed to be wider, thus allowing the electrolyte to penetrate the interior of the electrode body 30 more efficiently.

[0070] The proportion of the area of ​​the electrode body facing portion 60 when the area of ​​the bottom 30C of the electrode body 30 is set to 100% is not particularly limited, but is preferably, for example, 50% or more, 60% or more, 70% or more, or 80% or more. The larger the area of ​​the electrode body facing portion 60, the more the electrolyte present in the first space 62 can contact the impregnation area 38, and therefore, the impregnation efficiency can be improved. On the other hand, from the viewpoint of ensuring the area of ​​the overlapping portion 56 to prevent the first end 52 and the second end 54 from shifting, the above-mentioned proportion of the area of ​​the electrode body facing portion 60 is not particularly limited, but is preferably, for example, 95% or less or 90% or less.

[0071] The proportion of the overlapping portion 56 when the area of ​​the bottom 30C of the electrode body 30 is set to 100% is not particularly limited, but is preferably, for example, 50% or less, 40% or less, 30% or less, or 20% or less. The smaller the proportion of the overlapping portion 56, the easier it is for the electrolyte to pass through the gap between the opposing regions 57 of the overlapping portion 56, and therefore, the easier it is for the electrolyte to enter the first space 62. On the other hand, from the viewpoint of ensuring the area of ​​the overlapping portion 56 to prevent the first end 52 and the second end 54 from shifting, the above-mentioned proportion of the overlapping portion 56 is not particularly limited, but is preferably, for example, 5% or more or 10% or more.

[0072] like Figure 6 As shown, the thickness T of electrode body 30 (refer to...) Figure 6 The average length L1 of the second end 54 when set to 100 is not particularly limited, but is preferably 70 or more, 80 or more, or 90 or more. The longer the second end 54 is, the narrower the space between the first end 52 and the bottom wall 11 can be. Since the electrolyte may be trapped in this space, it is preferable that it is not too wide. On the other hand, if the space is too narrow, the electrolyte may have difficulty entering the first space 62 through the gap of the overlapping portion 56. Therefore, the average length L2 of the second end 54 is not particularly limited, but is preferably 98 or less or 95 or less.

[0073] like Figure 6 As shown, the thickness T of electrode body 30 (refer to...) Figure 6 The average length L1 of the first end portion 52 when set to 100 is not particularly limited, but is preferably 50 or less, 40 or less, 30 or less, or 20 or less. The shorter the first end portion 52, the wider the first space 62 can be. By making the first space 62 wider, more electrolyte is retained in the first space 62, thus improving the impregnation efficiency. On the other hand, if the first end portion 52 is too short, it is prone to curling up. Therefore, the average length L1 of the first end portion 52 is not particularly limited, but is preferably 5 or more or 10 or more.

[0074] like Figure 6 As shown, the thickness T of electrode body 30 (refer to...) Figure 6 The average length L3 of the overlapping portion 56 when set to 100 is not particularly limited, but is preferably 50 or less, 40 or less, 30 or less, or 20 or less. The shorter the average length L3 of the overlapping portion 56, the easier it is for the electrolyte to pass through the gap of the overlapping portion 56, and therefore, the easier it is for the electrolyte to enter the first space 62. On the other hand, from the viewpoint of ensuring the area of ​​the overlapping portion 56 to prevent the first end 52 from shifting from the second end 54, the average length L3 of the overlapping portion 56 is not particularly limited, but is preferably 5 or more or 10 or more.

[0075] The thickness of the resin film 50 is not particularly limited, but may be, for example, 50 μm or more, 100 μm or more, or 150 μm or more. A larger resin film 50 ensures a larger first space 62 and improves impregnation efficiency. On the other hand, a larger resin film 50 results in a smaller capacity for the energy storage device 1. Therefore, the thickness of the resin film 50 may be, for example, 300 μm or less, 250 μm or less, or 200 μm or less.

[0076] In the overlapping portion 56, the second end 54 and the first end 52 may also be partially fused, but preferably, the overlapping portion 56 is not fused in the region where the electrode body 30 faces the bottom wall 11. This is because the electrolyte can be supplied to the first space 62 more efficiently. In this embodiment, the resin film 50 is fused to the bottom side surface 42a of the first spacer 42 and the bottom side surface 44a of the second spacer 44. Thus, the resin film 50 can be fixed around the electrode body 30 without the overlapping portion 56 being fused in the region where the electrode body 30 faces the bottom wall 11.

[0077] The energy storage device 1 can be used for various purposes. Preferred applications include automotive applications, specifically, as a power source for driving vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). Additionally, the energy storage device 1 can be used as a battery, such as a small energy storage device. Typically, the energy storage device 1 can also be used as a battery module consisting of multiple batteries connected in series and / or in parallel.

[0078] The above descriptions of some embodiments are merely examples. This technology can be implemented in various other ways. The technology described in the claims includes technologies obtained by various modifications and alterations to the embodiments illustrated above. For example, a portion of the above embodiments can be replaced with other modifications, or other modifications can be added to the above embodiments. Furthermore, if a technical feature is not described as an essential technical feature, it can be appropriately deleted.

[0079] In the above-described embodiment, a first cover 10B is used as the first sidewall 17 having the liquid injection portion 19. However, in some embodiments, the first sidewall having the liquid injection portion may be part of the housing body.

[0080] In the above embodiments, the housing 10 has two covers 10B and 10C, but the number of covers is not particularly limited in this art. In some embodiments, there may be only one cover. Alternatively, the housing may not include any covers.

[0081] In the above embodiments, the walls constituting the housing are generally rectangular plate-like portions. However, in some embodiments, the walls constituting the housing may also be square or polygonal.

[0082] In the above-described embodiments, the electrode body 30 is a stacked electrode body with a tortuous structure using strip-shaped diaphragm sheets 36, but it is not limited to this as long as it is an electrode body having an impregnation region 38. For example, the electrode body may also be a stacked electrode body formed by preparing multiple diaphragm sheets and sandwiching and stacking one or more diaphragm sheets between the positive electrode sheet and the negative electrode sheet. Alternatively, it may be a wound electrode body formed by overlapping and winding strip-shaped positive electrode sheets and strip-shaped negative electrode sheets with strip-shaped diaphragm sheets in between. In the case of a wound electrode body, the impregnation region can be formed on both sides in the winding axis direction.

[0083] In the above embodiments, one electrode body 30 is housed in the housing 10, but in some embodiments, there may be multiple electrode bodies 30.

[0084] As described above, the following are examples of specific methods that can be used as specific embodiments of the technology disclosed herein.

[0085] Item 1: An energy storage device, comprising:

[0086] A housing with an injection section;

[0087] Electrode bodies housed within the aforementioned casing;

[0088] A resin film disposed between the aforementioned housing and the aforementioned electrode body in a manner that surrounds the aforementioned electrode body; and

[0089] The electrolyte contained in the aforementioned casing,

[0090] The aforementioned housing includes:

[0091] bottom wall;

[0092] The upper wall facing the aforementioned bottom wall; and

[0093] The first side wall extends from the edge of the bottom wall to the edge of the top wall.

[0094] The aforementioned injection section is located on the first side wall at a position closer to the upper wall than on the bottom wall.

[0095] The electrode body is configured such that its bottom faces the bottom wall.

[0096] The above-mentioned resin film has the following characteristics:

[0097] A first end extending from one side in a predetermined direction in a manner that covers a portion of the bottom of the aforementioned electrode body; and

[0098] The second end extends along the predetermined direction from the opposite direction to the first end and extends in a manner that covers a portion of the bottom of the electrode body.

[0099] A portion of the second end overlaps with the bottom wall side of the housing relative to the first end.

[0100] Item 2: In the energy storage device described in Item 1, in the predetermined direction, the average length of the first end is longer than the average length of the second end.

[0101] Item 3: In the energy storage device described in Item 1 or 2, the second end has an electrode body facing portion that is not separated from the first end and faces the electrode body.

[0102] When the area of ​​the bottom of the electrode is set to 100%, the ratio of the area of ​​the opposing portion of the electrode is 50% or more.

[0103] Item 4: In any one of Items 1 to 3, when the area of ​​the bottom of the electrode body is set to 100%, the ratio of the area of ​​the overlapping portion of the first end and the second end is 50% or less.

[0104] Item 5: In any one of items 1 to 4, when the thickness of the electrode body in the predetermined direction is set to 100, the average length of the second end is 70 or more.

[0105] Item 6: In any one of items 1 to 5, the average length of the first end when the thickness of the electrode body in the predetermined direction is set to 100 is 50 or less.

[0106] Item 7: In any one of items 1 to 6, in the portion where the first end and the second end overlap, the first end and the second end are not fused together.

[0107] Item 8: In any one of items 1 to 7, the energy storage device,

[0108] It also possesses both positive and negative extremes.

[0109] The aforementioned electrode has a positive electrode and a negative electrode.

[0110] The aforementioned positive terminal is electrically connected to the aforementioned positive electrode of the aforementioned electrode body.

[0111] The aforementioned negative terminal is electrically connected to the aforementioned negative terminal of the aforementioned electrode body.

[0112] The aforementioned housing also includes a second sidewall facing the first sidewall.

[0113] The aforementioned positive terminal is disposed on the aforementioned first sidewall or the aforementioned second sidewall.

[0114] The aforementioned negative terminal is disposed on the aforementioned first sidewall or the aforementioned second sidewall where the aforementioned positive terminal is not disposed.

[0115] Item 9: In the energy storage device described in Item 8, the housing includes:

[0116] The cylindrical shell body includes the aforementioned bottom wall and the aforementioned top wall;

[0117] As the first cover of the aforementioned first sidewall; and

[0118] As the second cover body of the aforementioned second sidewall

[0119] The aforementioned housing body has a first opening and a second opening located on the opposite side of the first opening.

[0120] The aforementioned first cover is installed at the aforementioned first opening.

[0121] The second cover is installed at the second opening.

[0122] Explanation of reference numerals in the attached figures

[0123] 1. Energy storage equipment

[0124] 10. Shell

[0125] 11 bottom wall

[0126] 12 upper wall

[0127] 17 First sidewall

[0128] 19 Liquid injection part

[0129] 30 Electrode Body

[0130] 38. Soaking area

[0131] 50 Resin Film

[0132] 52 First end

[0133] 54 Second end

[0134] 56 Overlapping parts

[0135] 60 Electrode body facing section

[0136] 62 First Space.

Claims

1. An energy storage device, wherein, have: The housing has a liquid injection section; An electrode body, which is housed within the housing; A resin film, wherein the resin film is disposed between the housing and the electrode body in a manner that surrounds the electrode body; as well as Electrolyte, which is contained within the casing. The housing includes: bottom wall; Upper wall, the upper wall facing the bottom wall; and A first sidewall extends from the edge of the bottom wall to the edge of the upper wall. The injection section is located on the first side wall at a position closer to the upper wall than on the bottom wall. The electrode body is configured such that its bottom faces the bottom wall. The resin film has the following characteristics: A first end, extending in a predetermined direction from one side in a manner that covers a portion of the bottom of the electrode body; and The second end extends along the predetermined direction from the opposite direction to the first end and extends in a manner that covers a portion of the bottom of the electrode body. A portion of the second end overlaps with the bottom wall side of the housing relative to the first end.

2. The energy storage device according to claim 1, wherein, In the predetermined direction, the average length of the first end is longer than the average length of the second end.

3. The energy storage device according to claim 1, wherein, The second end has an electrode body facing portion that is not separated from the first end and faces the electrode body. When the area of ​​the bottom of the electrode is set to 100%, the ratio of the area of ​​the opposing portion of the electrode is 50% or more.

4. The energy storage device according to claim 1, wherein, When the area of ​​the bottom of the electrode is set to 100%, the ratio of the area of ​​the overlapping portion of the first end and the second end is 50% or less.

5. The energy storage device according to claim 1, wherein, When the thickness of the electrode body in the predetermined direction is set to 100, the average length of the second end is 70 or more.

6. The energy storage device according to claim 1, wherein, When the thickness of the electrode body in the predetermined direction is set to 100, the average length of the first end is 50 or less.

7. The energy storage device according to claim 1, wherein, In the portion where the first end overlaps with the second end, the first end and the second end are not fused together.

8. The energy storage device according to any one of claims 1 to 7, wherein, The energy storage device also has a positive terminal and a negative terminal. The electrode body has a positive electrode and a negative electrode. The positive terminal is electrically connected to the positive electrode of the electrode body. The negative terminal is electrically connected to the negative electrode of the electrode body. The housing also has a second sidewall facing the first sidewall. The positive terminal is disposed on the first sidewall or the second sidewall. The negative terminal is disposed on the first sidewall or the second sidewall where the positive terminal is not disposed.

9. The energy storage device according to claim 8, wherein, The housing includes: A cylindrical shell body including the bottom wall and the top wall; As the first cover of the first sidewall; and As the second cover body of the second sidewall The housing body has a first opening and a second opening located on the opposite side of the first opening. The first cover is installed at the first opening. The second cover is installed in the second opening.

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