Power storage device

Abstract

To provide a power storage device capable of being miniaturized.SOLUTION: A power storage device comprises: a first power storage element 21A; and a second power storage element 21B. The first power storage element comprises: a first electrode body 30A; a first fixed member 90A that is arranged to a first side surface 31A of the first electrode body; and a first outer packing film 210A that houses the first electrode body or the first fixed member. The second power storage element comprises: a second electrode body 30B; a second fixed member 90B to be arranged to a second side surface 31B of the second electrode body; and a second outer packing film 210B that housing the second electrode body and the second fixed member. The first side surface and the second side surface are faced in a first direction. The first fixed member and the second fixed member are not faced in the first direction.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a power storage device.

Background Art

[0002] Patent Document 1 discloses an assembled battery configured by stacking rectangular batteries in the thickness direction. The rectangular battery includes an exterior body made of a flexible film such as a laminate film, and an electrode body inserted into the exterior body, the electrode body being composed of stacked positive electrodes, negative electrodes, and separators.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the rectangular battery included in the above - mentioned conventional assembled battery, an insulating tape is wound around the electrode body for shape retention, and the exterior body is formed of a flexible film. Therefore, the thickness of the insulating tape is likely to appear on the surface of the exterior body. As a result, when a plurality of rectangular batteries are stacked, for example, the thickness of the insulating tape can be accumulated more than the number of rectangular batteries. This becomes a factor in increasing the size of the assembled battery in the stacking direction of the rectangular batteries.

[0005] The present invention has been made by the inventors of the present application newly paying attention to the above problems, and an object thereof is to provide a power storage device capable of being miniaturized.

Means for Solving the Problems

[0006] The power storage device according to one aspect of the present invention includes a first power storage element and a second power storage element. The first power storage element includes a first electrode body, a first fixing member disposed on a first side surface of the first electrode body, and a first exterior film that houses the first electrode body and the first fixing member. The second power storage element includes a second electrode body, a second fixing member disposed on a second side surface of the second electrode body, and a second exterior film that houses the second electrode body and the second fixing member. The first side surface and the second side surface face each other in a first direction, and the first fixing member and the second fixing member do not face each other in the first direction.

Effects of the Invention

[0007] According to the present invention, a power storage device that can be miniaturized can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0009] (1) The power storage device according to one aspect of the present invention includes a first power storage element and a second power storage element. The first power storage element includes a first electrode body, a first fixing member disposed on a first side surface of the first electrode body, and a first exterior film that houses the first electrode body and the first fixing member. The second power storage element includes a second electrode body, a second fixing member disposed on a second side surface of the second electrode body, and a second exterior film that houses the second electrode body and the second fixing member. The first side surface and the second side surface face each other in a first direction, and the first fixing member and the second fixing member do not face each other in the first direction.

[0010] According to the power storage device according to one aspect of the present invention, the first power storage element and the second power storage element are arranged in the first direction, and the first fixing member and the second fixing member do not face each other in the first direction. That is, the two fixing members are not overlapped in the first direction, which is the arrangement direction of the first power storage element and the second power storage element. Thereby, an increase in the size of the power storage device in the first direction including the first power storage element and the second power storage element is suppressed. Therefore, the power storage device of this aspect is a power storage device that can be miniaturized.

[0011] (2) In the power storage device described in (1) above, the first electrode body may include a first positive electrode plate, a first negative electrode plate, and a first separator disposed between the first positive electrode plate and the first negative electrode plate. The second electrode body may include a second positive electrode plate, a second negative electrode plate, and a second separator disposed between the second positive electrode plate and the second negative electrode plate. The first separator includes a first outer peripheral portion that forms a part of the first side surface, and the second separator includes a second outer peripheral portion that forms a part of the second side surface. The first fixing member fixes the first outer peripheral portion to a portion of the first side surface other than the first outer peripheral portion, and the second fixing member fixes the second outer peripheral portion to a portion of the second side surface other than the second outer peripheral portion.

[0012] According to the power storage device described in (2) above, each of the first fixing member and the second fixing member can fix the end portion of the separator that forms the outermost periphery of the electrode body at positions where they cannot be overlapped in the first direction. Thereby, while suppressing an increase in the size of the power storage device in the first direction by the first fixing member and the second fixing member, it is possible to suppress displacement of the position of the portion of the separator disposed at the outermost periphery of the electrode body in the first electrode body and the second electrode body.

[0013] (3) In the power storage device described in (2) above, in a second direction intersecting the first direction, the first fixing member may be disposed on one side in the second direction from the center of the first electrode body, and the second fixing member may be disposed on the other side in the second direction from the center of the second electrode body.

[0014] According to the power storage device described in (3) above, for example, by rotating one of two power storage elements of the same model 180° around an axis parallel to a third direction intersecting the first direction and second direction, and arranging these two power storage elements in the first direction, a first power storage element and a second power storage element can be obtained. Therefore, a power storage device capable of miniaturization can be efficiently manufactured.

[0015] (4) In the power storage device described in (3) above, in the second direction, the first outer peripheral portion may be disposed on the one side in the second direction from the center of the first electrode body, and the second outer peripheral portion may be disposed on the other side in the second direction from the center of the second electrode body.

[0016] According to the power storage device described in (4) above, the outermost peripheral portion of the first separator facing the second power storage element and the outermost peripheral portion of the second separator facing the first power storage element do not overlap in the first direction. Therefore, an increase in the size of the power storage device in the first direction can be more reliably suppressed.

[0017] (5) In the power storage device according to any one of (1) to (4) above, the first power storage element includes a first positive electrode terminal and a first negative electrode terminal, the first positive electrode terminal and the first negative electrode terminal are arranged in a second direction intersecting the first direction, the second power storage element includes a second positive electrode terminal and a second negative electrode terminal, the second positive electrode terminal and the second negative electrode terminal are arranged in the second direction, the first positive electrode terminal and the second negative electrode terminal are arranged in the first direction, and the first negative electrode terminal and the second positive electrode terminal are arranged in the first direction.

[0018] According to the power storage device described in (5) above, the first positive electrode terminal and the second negative electrode terminal are adjacent to each other in the first direction, and the first negative electrode terminal and the second positive electrode terminal are adjacent to each other in the first direction. Therefore, when connecting the first power storage element and the second power storage element in series, by connecting the first positive electrode terminal and the second negative electrode terminal, or connecting the first negative electrode terminal and the second positive electrode terminal, an increase in the electrical resistance at the connection portion between the first power storage element and the second power storage element can be suppressed. Thereby, while suppressing an increase in the size of the power storage device in the first direction including the first power storage element and the second power storage element, an increase in the electrical resistance of the power storage device including the first power storage element and the second power storage element can be suppressed.

[0019] Hereinafter, with reference to the drawings, a power storage device according to an embodiment (including its modified examples) of the present invention will be described. Each of the embodiments described below shows comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, manufacturing processes, order of manufacturing processes, etc. shown in the following embodiments are examples and are not intended to limit the present invention. In each figure, dimensions, shapes, etc. are not strictly illustrated, and there may be cases where appropriate emphasis, omission, etc. are made. In each figure, the same or similar components are denoted by the same reference numerals.

[0020] In the following description and drawings, the arrangement direction of the main body of the exterior and the lid of the exterior of the power storage device, or the arrangement direction of a plurality of power storage elements included in the power storage device, is defined as the X-axis direction. The arrangement direction of a pair of terminals of one power storage element that protrude in the same direction, or the vertical direction, is defined as the Z-axis direction. A direction parallel to the protruding direction of a pair of terminals of one power storage element is defined as the Y-axis direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that intersect (orthogonal in the present embodiment) with each other. Depending on the usage mode, the Z-axis direction may not be the vertical direction, but hereinafter, for the sake of convenience of explanation, the Z-axis direction will be described as the vertical direction.

[0021] In the following description, the X-axis plus direction indicates the arrow direction of the X-axis, and the X-axis minus direction indicates the direction opposite to the X-axis plus direction. When simply referring to the X-axis direction, it indicates both directions of the X-axis plus direction and the X-axis minus direction or either one of the directions. Expressions indicating relative directions or postures such as parallel and orthogonal strictly include cases where they are not in that exact direction or posture. For example, when two directions are parallel, it not only means that the two directions are completely parallel, but also means that they are substantially parallel, that is, including a difference of, for example, about several percent. Further, in the following description, when expressing "insulation", it means "electrical insulation". A material having insulating properties is preferably formed from a material having a volume resistivity of 1×10 10 Ωm or more.

[0022] (Embodiment) [1. General description of the power storage device 1] First, a general description of the power storage device 1 according to the embodiment will be given with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing the appearance of the power storage device 1 according to the embodiment. FIG. 2 is an exploded perspective view of the power storage device 1 according to the embodiment.

[0023] The power storage device 1 is a device that can charge electricity from the outside and also discharge electricity to the outside. The power storage device 1 is, for example, a battery module (battery pack) used for power storage applications or power supply applications, etc. Specifically, the power storage device 1 is used, for example, as a battery for driving a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, an automatic guided vehicle (AGV), or a railway vehicle for electric railways, or for engine starting, etc. Examples of the above-mentioned automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, light oil, liquefied natural gas, etc.) vehicle. Examples of the above-mentioned railway vehicle for electric railways include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. Further, the power storage device 1 can also be used as a stationary battery used for household or business use, etc.

[0024] As shown in FIGS. 1 and 2, the power storage device 1 includes a power storage unit 20 and an exterior body 10 that houses the power storage unit 20. The exterior body 10 has an exterior body main body 11 that houses the power storage unit 20 and a lid body 12 that closes the exterior body main body 11.

[0025] The exterior body 10 is a rectangular (box-shaped) container (module case) that constitutes the exterior body of the power storage device 1. That is, the exterior body 10 protects the power storage unit 20 and the like housed inside from impacts and the like.

[0026] The exterior body main body 11 is a bottomed rectangular cylindrical member having an opening 111 in the +X-axis direction. The opening 111 is substantially square when viewed from the +X-axis direction. Inside the opening 111 of the exterior body main body 11, in addition to the power storage unit 20, a plurality of bus bars (not shown) electrically connected to the power storage unit 20 and the like are housed.

[0027] The lid 12 is a member that closes the opening 111 of the exterior body main body 11. The lid 12 is joined to the exterior body main body 11 in a state where the opening 111 of the exterior body main body 11 is blocked from the positive X-axis direction. Inside the lid 12, a circuit board including, for example, a detection circuit for detecting the state of each power storage element 21, a control circuit for controlling charging and discharging, and electric wires (not shown) can be accommodated. The lid 12 has a pair of (positive and negative) external terminals 81. The external terminals 81 are electrically connected to a plurality of power storage elements 21 included in the power storage unit 20. The power storage device 1 charges electricity from the outside and discharges electricity to the outside via the pair of external terminals 81. The external terminals 81 are formed of a metal conductive member such as a copper alloy such as brass, copper, aluminum, or an aluminum alloy.

[0028] The exterior body main body 11 and the lid 12 of the exterior body 10 are formed of an insulating member such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene·perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyether sulfone (PES), polyamide (PA), ABS resin, or a composite material thereof, or a metal with insulating coating. Thereby, the exterior body 10 avoids the power storage unit 20 and the like from coming into contact with external metal members and the like. The exterior body main body 11 and the lid 12 may be formed of the same material or different materials.

[0029] The power storage unit 20 includes a power storage element row 29 including a plurality of power storage elements 21 arranged in the X-axis direction, and a holding member 400 that holds the power storage element row 29. The power storage element 21 is a secondary battery (single cell) that can charge and discharge electricity. More specifically, it is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. In the present embodiment, the power storage element 21 is a pouch-type power storage element having a flat shape. In the present embodiment, four pouch-type power storage elements 21 are arranged side by side in the X-axis direction. The power storage element 21 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The power storage element 21 may be a primary battery instead of a secondary battery. Details of the power storage element 21 and the power storage element row 29 will be described later with reference to FIGS. 3 to 8.

[0030] The holding member 400 is a member that holds the power storage element row 29. Specifically, the power storage unit 20 includes a first holding member 401 and a second holding member 402, which are a pair of holding members 400. The first holding member 401 is arranged in the minus X-axis direction of the power storage element row 29 and is joined to the power storage element 21 at the end in the minus X-axis direction of the power storage element row 29 by a double-sided tape 300. The second holding member 402 is arranged in the plus X-axis direction of the power storage element row 29 and is joined to the power storage element 21 at the end in the plus X-axis direction of the power storage element row 29 by a double-sided tape 300. The first holding member 401 and the second holding member 402 are formed of an insulating member such as PC, PP, PE, PS, PPS, or PPE exemplified as the material for forming the exterior body 10. Thereby, the first holding member 401 and the second holding member 402 suppress the power storage element row 29 from being electrically connected to a conductive member such as an external metal member. The first holding member 401 and the second holding member 402 also have a function of protecting the plurality of power storage elements 21 from vibration or impact.

[0031] [2. Configuration of Power Storage Element Row 29 and Power Storage Element 21] Next, in addition to FIGS. 1 and 2 described above, the configuration of the energy storage element array 29 and the energy storage element 21 according to the embodiment will be described with reference to FIGS. 3 to 8. FIG. 3 is an exploded perspective view of the energy storage element array 29 according to the embodiment. In FIG. 3, the approximate outer shape of the double-sided tape 300 is represented by a dotted line.

[0032] As shown in FIG. 3, the energy storage element array 29 according to the present embodiment includes four energy storage elements 21 arranged in the X-axis direction. Two adjacent energy storage elements 21 in the X-axis direction among the four energy storage elements 21 are joined by a double-sided tape 300. Each of these four energy storage elements 21 is a pouch-type energy storage element as described above. The basic configuration of the energy storage element 21 is described as follows. The following description of the configuration of the energy storage element 21 applies to each of the four energy storage elements 21.

[0033] The energy storage element 21 has an exterior film 210, a positive electrode terminal 22, and a negative electrode terminal 25. Inside the exterior film 210, an electrode body 30 and an electrolytic solution (not shown) are accommodated. The type of the electrolytic solution is not particularly limited as long as it does not impair the performance of the energy storage element 21, and a known material can be appropriately used.

[0034] The exterior film 210 is a sheet-like exterior body formed of a laminated film, and houses an electrode body 30, an electrolytic solution, etc. in a sealed state under reduced pressure inside. The exterior film 210 is configured by overlapping two rectangular laminated films in the X-axis direction. The two laminated films are joined (sealed) by heat welding or the like with the positive electrode terminal 22 and the negative electrode terminal 25 interposed therebetween. In the two laminated films, at locations not corresponding to the pair of positive electrode terminal 22 and negative electrode terminal 25, the two laminated films are joined (sealed) by heat welding or the like. The laminated film is a flexible film composed of a plurality of layers including a metal layer such as aluminum and a resin layer such as polypropylene (PP) or polyethylene (PE), and the resin layer is disposed at the welded location (sealing portion). Note that the exterior film 210 may be configured by forming a single laminated film into a bag shape and joining the ends of the laminated film by heat welding.

[0035] In the present embodiment, the electrode body 30 is a wound-type electrode body formed by laminating and winding a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is an electrode plate having a positive electrode active material layer formed on the surface of a positive electrode current collector foil which is a long strip-shaped metal foil. The negative electrode plate is an electrode plate having a negative electrode active material layer formed on the surface of a negative electrode current collector foil which is a long strip-shaped metal foil. The positive electrode active material layer contains a positive electrode active material, a binder, a conductive material, etc. The negative electrode active material layer contains a negative electrode active material, a binder, a thickener, etc. As the positive electrode active material and the negative electrode active material, any known material can be appropriately used as long as it is a material capable of occluding and releasing lithium ions. The separator is a microporous sheet made of resin. As the material of the separator, any known material can be appropriately used as long as it does not impair the performance of the power storage element 21. For example, as the separator, a woven fabric insoluble in an organic solvent, a non-woven fabric, a synthetic resin microporous membrane made of a polyolefin resin such as polyethylene, etc. can be used.

[0036] The positive electrode terminal 22 and the negative electrode terminal 25 are conductive plate-like members (also called lead plates) electrically connected to the electrode body 30, and are arranged to be exposed from the exterior film 210 in a state of penetrating the exterior film 210. In the present embodiment, the positive electrode terminal 22 and the negative electrode terminal 25 arranged in the Z-axis direction protrude in the minus Y-axis direction from the end portion of the exterior film 210 in the minus Y-axis direction.

[0037] The positive electrode terminal 22 is electrically connected to the positive electrode plate of the electrode body 30. The negative electrode terminal 25 is electrically connected to the negative electrode plate of the electrode body 30. That is, the positive electrode terminal 22 and the negative electrode terminal 25 are metal terminals for leading out the electricity stored in the electrode body 30 to the external space of the power storage element 21 and introducing electricity into the internal space of the power storage element 21 to store electricity in the electrode body 30. The positive electrode terminal 22 and the negative electrode terminal 25 are formed of aluminum, aluminum alloy, copper, copper alloy, or the like.

[0038] In the power storage element row 29 including four power storage elements 21 each configured as described above, these four power storage elements 21 are electrically connected in series. Specifically, one of the positive electrode terminal 22 and the negative electrode terminal 25 adjacent in the X-axis direction is bent in a direction approaching the other of the positive electrode terminal 22 and the negative electrode terminal 25. As a result, the tip portions of the positive electrode terminal 22 and the negative electrode terminal 25 are in a posture substantially parallel to the XZ plane as shown in FIG. 3, and the tip portions are joined in this state. That is, the positive electrode terminal 22 and the negative electrode terminal 25 adjacent in the X-axis direction are joined. In the power storage element row 29 according to the present embodiment, three sets of positive electrode terminals 22 and negative electrode terminals 25 are joined, whereby the four power storage elements 21 are electrically connected in series. There is no particular limitation on the method of joining the positive electrode terminal 22 and the negative electrode terminal 25. For example, methods such as ultrasonic welding, resistance welding, or laser welding are used. Members such as bolts or rivets may be used for joining the positive electrode terminal 22 and the negative electrode terminal 25.

[0039] In the energy storage element array 29 including a plurality of energy storage elements 21 arranged in the X-axis direction as described above, at least two energy storage elements 21 have a configuration for suppressing an increase in the size of the energy storage element array 29 in the X-axis direction. Hereinafter, these two energy storage elements 21 will be described in detail as the first energy storage element 21A and the second energy storage element 21B. In the present embodiment, the first energy storage element 21A is the energy storage element 21 at the end in the negative X-axis direction in the energy storage element array 29. The second energy storage element 21B is an energy storage element 21 that is adjacent to the first energy storage element 21A and is arranged in the positive X-axis direction of the first energy storage element 21A. That is, the first energy storage element 21A and the second energy storage element 21B are the first and second energy storage elements 21 counted from the end in the negative X-axis direction in the energy storage element array 29.

[0040] [3. Configuration of the First Energy Storage Element 21A and the Second Energy Storage Element 21B] FIG. 4 is a cross-sectional view showing a schematic configuration of the first energy storage element 21A according to the embodiment. Specifically, in FIG. 4, a cross-section taken along line IV-IV in FIG. 3 is simply illustrated. In FIG. 4, two laminate films constituting the first exterior film 210A are separated in the X-axis direction and illustrated. In FIG. 4, a state in which the first fixing member 90A is separated from the first electrode body 30A and the end portion of the first separator 34A is floated outward is illustrated. In FIGS. 4 to 9, the illustration of the double-sided tape 300 is omitted.

[0041] FIG. 5 is a side view showing a schematic configuration of the first energy storage element 21A according to the embodiment. In FIG. 5, the illustration of the first exterior film 210A is omitted, and the first positive electrode terminal 22A and the first negative electrode terminal 25A are illustrated in a state where they are not bent.

[0042] FIG. 6 is a cross-sectional view showing a schematic configuration of the second power storage element 21B according to the embodiment. In FIG. 6, a cross-section taken along line VI-VI in FIG. 3 is simply illustrated. In FIG. 6, two laminate films constituting the second exterior film 210B are shown separated in the X-axis direction. In FIG. 6, the second fixing member 90B is shown separated from the second electrode body 30B, and the end portion of the second separator 34B is shown floating outward. FIG. 7 is a side view showing a schematic configuration of the second power storage element 21B according to the embodiment. In FIG. 7, the illustration of the second exterior film 210B is omitted, and the second positive electrode terminal 22B and the second negative electrode terminal 25B are shown in a non-folded state.

[0043] FIG. 8 is a cross-sectional view showing a schematic configuration of the first power storage element 21A and the second power storage element 21B according to the embodiment. The position of the cross-section of the first power storage element 21A in FIG. 8 corresponds to the position of the cross-section in FIG. 4, and the position of the cross-section of the second power storage element 21B in FIG. 8 corresponds to the position of the cross-section in FIG. 6.

[0044] As shown in FIGS. 4 and 5, the first power storage element 21A includes a first electrode body 30A, a first exterior film 210A that houses the first electrode body 30A, a first positive electrode terminal 22A, and a first negative electrode terminal 25A.

[0045] The first electrode body 30A includes a first positive electrode plate 32A, a first negative electrode plate 33A, and a first separator 34A disposed between the first positive electrode plate 32A and the first negative electrode plate 33A. Specifically, the first electrode body 30A is formed by laminating the first positive electrode plate 32A and the first negative electrode plate 33A with the first separator 34A interposed therebetween and winding them around a winding axis W1 (a virtual axis parallel to the Y-axis direction in the present embodiment).

[0046] The first electrode body 30A, which is a wound electrode body, has a flat shape in a direction orthogonal to the winding axis W1 (the X-axis direction in the present embodiment). That is, when viewed from the direction of the winding axis W1, the first electrode body 30A has an overall oval shape, the straight portion of the oval shape is flat, and the curved portion of the oval shape is curved. For this reason, as shown in FIGS. 4 and 5, the first electrode body 30A has a pair of first curved end portions 39A and an intermediate portion that is a portion between the pair of first curved end portions 39A. In the present embodiment, the side surface of the intermediate portion of the first electrode body 30A on the side facing the second power storage element 21B, that is, the side surface in the +X-axis direction, is referred to as the first side surface 31A.

[0047] A first fixing member 90A is disposed on the first side surface 31A of the first electrode body 30A having such a configuration. In the present embodiment, the first fixing member 90A is a member that fixes the end portion of the first separator 34A at the outermost periphery of the first electrode body 30A. Specifically, as shown in FIGS. 4 and 5, the first separator 34A includes a first outer peripheral portion 34Aa that forms a part of the first side surface 31A. The first outer peripheral portion 34Aa is a portion of the outermost periphery of the first separator 34A that faces the second power storage element 21B in the X-axis direction. The first fixing member 90A fixes the first outer peripheral portion 34Aa to a portion of the first side surface 31A other than the first outer peripheral portion 34Aa. The portion other than the first outer peripheral portion 34Aa is a portion of the first separator 34A that is closer to the center of the electrode body than the first outer peripheral portion 34Aa (the -X-axis direction in FIG. 4). In the present embodiment, an adhesive tape having an adhesive layer only on one side is adopted as the first fixing member 90A. That is, the first outer peripheral portion 34Aa is fixed to a portion of the first separator 34A that is closer to the center of the electrode body than the first outer peripheral portion 34Aa by the adhesive tape that is the first fixing member 90A. The portion closer to the center of the electrode body than the first outer peripheral portion 34Aa can be rephrased as a position closer to the center of the electrode body than the first outer peripheral portion 34Aa.

[0048] More specifically, the first fixing member 90A fixes the edge of the first outer peripheral portion 34Aa in the winding direction of the first separator 34A (clockwise in FIG. 4) to a portion of the first side surface 31A other than the first outer peripheral portion 34Aa. In the present embodiment, as shown in FIG. 5, the first fixing member 90A is arranged to extend in the Y-axis direction along the edge of the first outer peripheral portion 34Aa. The first fixing member 90A is arranged on one side in the Z-axis direction rather than at the center Ca of the first electrode body 30A in the Z-axis direction. In the present embodiment, the first fixing member 90A is arranged in the +Z-axis direction rather than at the center Ca of the first electrode body 30A.

[0049] With respect to the first fixing member 90A arranged as described above, the second fixing member 90B included in the second energy storage element 21B is arranged at a position not facing the first fixing member 90A in the X-axis direction. Specifically, the second energy storage element 21B is configured as follows.

[0050] As shown in FIGS. 6 and 7, the second energy storage element 21B includes a second electrode body 30B, a second exterior film 210B that houses the second electrode body 30B, a second positive electrode terminal 22B, and a second negative electrode terminal 25B.

[0051] The second electrode body 30B includes a second positive electrode plate 32B, a second negative electrode plate 33B, and a second separator 34B arranged between the second positive electrode plate 32B and the second negative electrode plate 33B. Specifically, the second electrode body 30B is formed by laminating the second positive electrode plate 32B and the second negative electrode plate 33B with the second separator 34B interposed therebetween and winding them around a winding axis W2 (a virtual axis parallel to the Y-axis direction in the present embodiment).

[0052] The second electrode body 30B, which is a wound electrode body, is also flat in a direction orthogonal to the winding axis W2 (the X-axis direction in this embodiment), similar to the first electrode body 30A. That is, as shown in FIGS. 6 and 7, the second electrode body 30B has a pair of second curved end portions 39B and an intermediate portion that is a portion between the pair of second curved end portions 39B. In this embodiment, the side surface of the intermediate portion of the second electrode body 30B on the side facing the first power storage element 21A, i.e., the side surface in the minus X-axis direction, is referred to as the second side surface 31B. The second side surface 31B faces the first side surface 31A in the X-axis direction. In this embodiment, the X-axis direction is an example of the first direction. The first direction can also be described as the arrangement direction of the first power storage element 21A and the second power storage element 21B, or the thickness direction of the first power storage element 21A and / or the second power storage element 21B. The Z-axis direction is an example of a second direction that intersects the first direction. In this case, the first direction and the Y-axis direction that intersects the first and second directions may be regarded as the third direction.

[0053] A second fixing member 90B is disposed on the second side surface 31B of the second electrode body 30B having such a configuration. In this embodiment, the second fixing member 90B is a member that fixes the end portion of the second separator 34B at the outermost periphery of the second electrode body 30B. Specifically, as shown in FIGS. 6 and 7, the second separator 34B includes a second outer peripheral portion 34Bb that forms a part of the second side surface 31B. The second outer peripheral portion 34Bb is a portion of the outermost periphery of the second separator 34B that faces the first power storage element 21A in the X-axis direction. The second fixing member 90B fixes the second outer peripheral portion 34Bb to a portion of the second side surface 31B other than the second outer peripheral portion 34Bb. The portion other than the second outer peripheral portion 34Bb is a portion of the second separator 34B that is closer to the center of the electrode body than the second outer peripheral portion 34Bb (the plus X-axis direction in FIG. 6). In this embodiment, an adhesive tape having an adhesive layer only on one side is employed as the second fixing member 90B. That is, the second outer peripheral portion 34Bb is fixed to a portion of the second separator 34B that is closer to the center of the electrode body than the second outer peripheral portion 34Bb by the adhesive tape that is the second fixing member 90B. The portion closer to the center of the electrode body than the second outer peripheral portion 34Bb of the second separator 34B can be rephrased as a position closer to the center of the electrode body than the second outer peripheral portion 34Bb.

[0054] More specifically, the second fixing member 90B fixes the edge of the second outer peripheral portion 34Bb in the winding direction of the second separator 34B (clockwise in FIG. 6) to a portion of the second side surface 31B other than the second outer peripheral portion 34Bb. In the present embodiment, as shown in FIG. 7, the second fixing member 90B is arranged to extend in the Y-axis direction along the edge of the second outer peripheral portion 34Bb. The second fixing member 90B is arranged on the other side in the Z-axis direction than the center Cb of the second electrode body 30B in the Z-axis direction. In the present embodiment, the second fixing member 90B is arranged in the minus Z-axis direction than the center Cb of the second electrode body 30B.

[0055] In the present embodiment, the thicknesses of the first separator 34A included in the first electrode body 30A and the second separator 34B included in the second electrode body 30B are both, for example, about 16 μm. The thicknesses of the first fixing member 90A and the second fixing member 90B are both, for example, about 40 μm. The film thicknesses of the first outer packaging film 210A included in the first power storage element 21A and the second outer packaging film 210B included in the second power storage element 21B are both, for example, about 150 μm. That is, the thickness of the second fixing member 90B is about 30% of the film thickness of the second outer packaging film 210B.

[0056] Furthermore, the first outer packaging film 210A and the second outer packaging film 210B are formed of a laminate film, which is a flexible film composed of a plurality of layers including a metal layer such as aluminum and a resin layer such as PP or PE as described above. Therefore, when the first electrode body 30A is housed inside the first outer packaging film 210A and the first outer packaging film 210A is sealed in a reduced pressure state, the thickness of the first fixing member 90A arranged on the first electrode body 30A appears on the outer surface of the first outer packaging film 210A. That is, a first convex portion 219A is formed on the side surface in the plus X-axis direction of the first outer packaging film 210A by being pushed by the first fixing member 90A from the inside of the first outer packaging film 210A.

[0057] The same applies to the second exterior film 210B, and the thickness of the second fixing member 90B disposed on the second electrode body 30B appears on the outer surface of the second exterior film 210B. That is, a second convex portion 219B is formed on the side surface of the second exterior film 210B in the negative X-axis direction by being pushed by the second fixing member 90B from the inside of the second exterior film 210B.

[0058] In this way, when a plurality of power storage elements 21 each having a convex portion on the side surface in the X-axis direction are arranged in the X-axis direction, the size of the power storage element row 29 in the X-axis direction can increase only by the product of the length in the protruding direction of the convex portion and the number of power storage elements 21. This becomes a factor that hinders the miniaturization of the power storage device 1.

[0059] Regarding this point, in the present embodiment, as shown in FIGS. 4, 6, and 8, the first fixing member 90A and the second fixing member 90B are arranged at positions that do not face each other in the X-axis direction on the side surfaces (the first side surface 31A and the second side surface 31B) of the first electrode body 30A and the second electrode body 30B that face each other. Thereby, the first convex portion 219A formed by the first fixing member 90A and the second convex portion 219B formed by the second fixing member 90B do not face each other in the X-axis direction. As a result, an increase in the size of the power storage element row 29 in the X-axis direction is suppressed.

[0060] As described above, the power storage device 1 according to the present embodiment includes a first power storage element 21A and a second power storage element 21B. The first power storage element 21A includes a first electrode body 30A, a first fixing member 90A disposed on the first side surface 31A of the first electrode body 30A, and a first exterior film 210A that houses the first electrode body 30A and the first fixing member 90A. The second power storage element 21B includes a second electrode body 30B, a second fixing member 90B disposed on the second side surface 31B of the second electrode body 30B, and a second exterior film 210B that houses the second electrode body 30B and the second fixing member 90B. The first side surface 31A and the second side surface 31B face each other in the X-axis direction. The first fixing member 90A and the second fixing member 90B do not face each other in the X-axis direction.

[0061] Thus, in the power storage device 1 according to this embodiment, the first power storage element 21A and the second power storage element 21B are arranged in the X-axis direction. Further, the first fixing member 90A is disposed on the first side surface 31A of the first electrode body 30A facing the second power storage element 21B, and the second fixing member 90B is disposed on the second side surface 31B of the second electrode body 30B facing the first power storage element 21A. In such a configuration, the first fixing member 90A and the second fixing member 90B are disposed at positions not facing each other in the X-axis direction. That is, the first fixing member 90A and the second fixing member 90B are not overlapped in the X-axis direction which is the arrangement direction of the first power storage element 21A and the second power storage element 21B. Thereby, an increase in the size of the power storage device 1 in the X-axis direction including the first power storage element 21A and the second power storage element 21B is suppressed. Therefore, according to the power storage device 1 of this aspect, miniaturization is possible.

[0062] Each of the plurality of power storage elements 21 included in the power storage element array 29 provided in the power storage device 1 is a pouch-type power storage element including an electrode body 30 and an exterior film 210 that houses the electrode body 30 as described above. When forming the laminate film that forms the exterior film 210, for example, when the bending angle during molding using a mold becomes large, there is a high possibility that defects will occur in the bent portion. When forming a housing portion for housing the electrode body 30 in the exterior film 210, the greater the depth of the housing portion, the more prominent the defect in the bent portion becomes. Therefore, from the viewpoint of suppressing the occurrence of such defects, it is preferable that the thickness of the electrode body 30 housed in the exterior film 210 (the thickness in the X-axis direction according to the present embodiment, the same applies hereinafter) is thin. As a result, the thickness of the power storage element 21 becomes relatively small. However, when the thickness of the power storage element 21 becomes small, the thickness of a convex portion such as the first convex portion 219A (see FIG. 8) formed in the exterior film 210 becomes a large ratio with respect to the maximum thickness of the power storage element 21. That is, the possibility that the thickness of the convex portion cannot be ignored increases. Furthermore, when molding the exterior film 210 by pressing the laminate film using a mold, the laminate film is easier to mold when it is thin. However, the thinning of the laminate film leads to the fact that convex portions due to fixing members such as the first fixing member 90A are likely to occur in the exterior film 210, and the protruding length of the convex portions becomes large. Regarding these problems, in the power storage device 1 according to the present embodiment, the first fixing member 90A included in the first power storage element 21A and the second fixing member 90B included in the second power storage element 21B do not face each other in the X-axis direction. Therefore, even when the first convex portion 219A and the second convex portion 219B having a relatively large protruding length are formed due to the thin laminate film, an increase in the size of the power storage element array 29 in the X-axis direction due to the first convex portion 219A and the second convex portion 219B is suppressed. That is, the configuration provided in the power storage device 1 according to the present embodiment is useful for miniaturizing a power storage device including a plurality of power storage elements each of which is a pouch-type power storage element.

[0063] In this embodiment, among the four power storage elements 21 included in the power storage element array 29, the configurations of the first power storage element 21A and the second power storage element 21B, which are the first and second power storage elements 21 from the end in the negative X-axis direction, have been described (see FIG. 3). However, the first and second power storage elements 21, which are the other two power storage elements 21, from the end in the positive X-axis direction may have the same configuration as the first power storage element 21A and the second power storage element 21B. That is, when the first power storage element 21A and the second power storage element 21B are taken as a set of power storage elements 21, the power storage element array 29 may be formed by arranging two sets of the power storage elements 21 in the X-axis direction. In this case, for example, in FIG. 8, the first power storage element 21A is additionally arranged in the positive X-axis direction of the second power storage element 21B. Further, the first fixing member 90A is not arranged on a portion other than the first side surface 31A of the first electrode body 30A, and the second fixing member 90B is not arranged on a portion other than the second side surface 31B of the second electrode body 30B. Therefore, the side surface of the second power storage element 21B in the positive X-axis direction is a flat surface, and the side surface of the first power storage element 21A in the negative X-axis direction is a flat surface. That is, when the first power storage element 21A is arranged in the positive X-axis direction of the second power storage element 21B, the flat surfaces of the second power storage element 21B and the first power storage element 21A face each other. Therefore, in these second power storage element 21B and first power storage element 21A, the problem that the first convex portion 219A and the second convex portion 219B overlap in the X-axis direction does not occur.

[0064] In the power storage device 1 according to the present embodiment, as shown in FIG. 4, the first electrode body 30A includes a first positive electrode plate 32A, a first negative electrode plate 33A, and a first separator 34A disposed between the first positive electrode plate 32A and the first negative electrode plate 33A. As shown in FIG. 6, the second electrode body 30B includes a second positive electrode plate 32B, a second negative electrode plate 33B, and a second separator 34B disposed between the second positive electrode plate 32B and the second negative electrode plate 33B. The first separator 34A includes a first outer peripheral portion 34Aa that forms a part of the first side surface 31A, and the second separator 34B includes a second outer peripheral portion 34Bb that forms a part of the second side surface 31B. The first fixing member 90A fixes the first outer peripheral portion 34Aa to a portion of the first side surface 31A other than the first outer peripheral portion 34Aa. The second fixing member 90B fixes the second outer peripheral portion 34Bb to a portion of the second side surface 31B other than the second outer peripheral portion 34Bb.

[0065] Thus, in the present embodiment, each of the first fixing member 90A and the second fixing member 90B is disposed at a position where they do not overlap each other in the X-axis direction, and can fix the end portion of the separator that forms the outermost periphery of the electrode body. Specifically, as shown in FIG. 4, the first fixing member 90A fixes the first outer peripheral portion 34Aa of the first separator 34A. As shown in FIG. 6, the second fixing member 90B is disposed at a position that does not face the first fixing member 90A in the X-axis direction, and fixes the second outer peripheral portion 34Bb of the second separator 34B. Thereby, while suppressing an increase in the size of the power storage device 1 in the X-axis direction by the first fixing member 90A and the second fixing member 90B, displacement of the portion of the first separator 34A disposed at the outermost periphery of the first electrode body 30A and displacement of the portion of the second separator 34B disposed at the outermost periphery of the second electrode body 30B can be suppressed.

[0066] In the power storage device 1 according to the present embodiment, more specifically, in the Z-axis direction orthogonal to the X-axis direction, the first fixing member 90A is disposed on one side in the Z-axis direction from the center Ca of the first electrode body 30A. The second fixing member 90B is disposed on the other side in the Z-axis direction from the center Cb of the second electrode body 30B. More specifically, as shown in FIGS. 4 and 5, the first fixing member 90A is disposed in the positive Z-axis direction from the center Ca of the first electrode body 30A. As shown in FIGS. 6 and 7, the second fixing member 90B is disposed in the negative Z-axis direction from the center Cb of the second electrode body 30B.

[0067] According to this configuration, for example, one of two power storage elements 21 of the same model is rotated 180° around an axis parallel to the Y-axis direction orthogonal to the X-axis direction and the Z-axis direction, and these two power storage elements 21 are arranged in the X-axis direction, whereby the first power storage element 21A and the second power storage element 21B are obtained. For example, by rotating the first power storage element 21A shown in FIGS. 4 and 5 by 180° around the Y-axis, a power storage element 21 having the same configuration as the second power storage element 21B shown in FIGS. 6 and 7 is obtained. Therefore, the power storage device 1 that can be miniaturized can be efficiently manufactured.

[0068] In the power storage device 1 according to the present embodiment, in the Z-axis direction, the first outer peripheral portion 34Aa is disposed on one side in the Z-axis direction from the center Ca of the first electrode body 30A, and the second outer peripheral portion 34Bb is disposed on the other side in the Z-axis direction from the center Cb of the second electrode body 30B (see FIGS. 4 to 7).

[0069] Thus, in the present embodiment, the outermost peripheral portion of the first separator 34A facing the second power storage element 21B and the outermost peripheral portion of the second separator 34B facing the first power storage element 21A do not overlap in the X-axis direction. Therefore, an increase in the size of the power storage device 1 in the X-axis direction can be more reliably suppressed.

[0070] In the power storage device 1 according to the present embodiment, the first power storage element 21A includes a first positive electrode terminal 22A and a first negative electrode terminal 25A. The first positive electrode terminal 22A and the first negative electrode terminal 25A are arranged in the Z-axis direction. The second power storage element 21B includes a second positive electrode terminal 22B and a second negative electrode terminal 25B. The second positive electrode terminal 22B and the second negative electrode terminal 25B are arranged in the Z-axis direction. The first positive electrode terminal 22A and the second negative electrode terminal 25B are arranged in the X-axis direction, and the first negative electrode terminal 25A and the second positive electrode terminal 22B are arranged in the X-axis direction.

[0071] That is, in the present embodiment, as shown in FIG. 3, for example, the first positive electrode terminal 22A and the second negative electrode terminal 25B are adjacent to each other in the X-axis direction, and the first negative electrode terminal 25A and the second positive electrode terminal 22B are adjacent to each other in the X-axis direction. Therefore, by connecting the first positive electrode terminal 22A and the second negative electrode terminal 25B, or by connecting the first negative electrode terminal 25A and the second positive electrode terminal 22B, it is easy to connect the first power storage element 21A and the second power storage element 21B in series. Further, when the first power storage element 21A and the second power storage element 21B are connected in series in this way, an increase in the electrical resistance at the connection portion between the first power storage element 21A and the second power storage element 21B can be suppressed. In the present embodiment, as shown in FIGS. 2 and 3, the tip portions of the first positive electrode terminal 22A and the second negative electrode terminal 25B arranged in the X-axis direction are bent in a direction approaching each other, and these tip portions are joined. Thereby, for example, an increase in the size of the power storage element row 29 in the Y-axis direction is suppressed.

[0072] In the power storage element row 29 included in the power storage device 1, it is not essential that one of the positive electrode terminal 22 and the negative electrode terminal 25 adjacent to each other in the X-axis direction is bent in a direction approaching the other of the positive electrode terminal 22 and the negative electrode terminal 25. For example, in a state where both the positive electrode terminal 22 and the negative electrode terminal 25 adjacent to each other in the X-axis direction are flat plates parallel to the YZ plane, while pressing one of the positive electrode terminal 22 and the negative electrode terminal 25 against the other in the X-axis direction, the positive electrode terminal 22 and the negative electrode terminal 25 may be joined by welding or bolts or the like.

[0073] The above described the power storage device 1 according to the embodiment, centering on the configurations of the first power storage element 21A and the second power storage element 21B. However, the power storage device 1 may include first and second power storage elements having configurations different from those shown in FIGS. 2 to 8. Therefore, a modified example of the power storage device 1 will be described below, centering on the differences from the above embodiment.

[0074] [4. Modified Example] FIG. 9 is a cross-sectional view showing a schematic configuration of a first power storage element 121A and a second power storage element 121B according to a modified example of the embodiment. In FIG. 9, cross-sections of the first power storage element 121A and the second power storage element 121B in the XY plane passing through the center in the Z-axis direction of the first power storage element 121A and the second power storage element 121B are simply illustrated. Although not shown in FIG. 9, for example, the first positive electrode terminal 22A and the second negative electrode terminal 25B are electrically connected, so that the first power storage element 121A and the second power storage element 121B are electrically connected in series.

[0075] The power storage device 1 according to this modified example includes a power storage element row 29a, and the power storage element row 29a includes a plurality of power storage elements 121. The plurality of power storage elements 121 include at least the first power storage element 121A and the second power storage element 121B, and are arranged in the X-axis direction.

[0076] In the power storage device 1 according to this modified example, the first power storage element 121A includes a first electrode body 130A, a first fixing member 90A disposed on a first side surface 131A of the first electrode body 130A, and a first exterior film 210A that houses the first electrode body 130A and the first fixing member 90A. The second power storage element 121B includes a second electrode body 130B, a second fixing member 90B disposed on a second side surface 131B of the second electrode body 130B, and a second exterior film 210B that houses the second electrode body 130B and the second fixing member 90B. The first side surface 131A and the second side surface 131B face each other in the X-axis direction. The first fixing member 90A and the second fixing member 90B do not face each other in the X-axis direction. These configurations are common to the power storage device 1 according to the above embodiment.

[0077] In this modified example, the range in which the first fixing member 90A is arranged in the Y-axis direction and the range in which the second fixing member 90B is arranged in the Y-axis direction do not overlap. That is, in this modified example, the first fixing member 90A and the second fixing member 90B are arranged at different positions from each other in the Y-axis direction, and are different from the above-described embodiment at least in this respect. Even in this case, the first fixing member 90A and the second fixing member 90B do not face each other in the X-axis direction. As a result, as shown in FIG. 9, the first convex portion 1219A formed on the first power storage element 121A by the first fixing member 90A and the second convex portion 1219B formed on the second power storage element 121B by the second fixing member 90B do not face each other in the X-axis direction. As a result, an increase in the size of the power storage element row 29a in the X-axis direction is suppressed. Thereby, miniaturization of the power storage device 1 including the power storage element row 29a becomes possible.

[0078] In this modified example, at least a part of the range in which the first fixing member 90A is arranged in the Z-axis direction and at least a part of the range in which the second fixing member 90B is arranged in the Z-axis direction overlap. However, this is not essential. For example, the first fixing member 90A and the second fixing member 90B according to this modified example may be arranged at different positions from each other in the Z-axis direction, similarly to the first fixing member 90A and the second fixing member 90B (see FIG. 8) according to the above-described embodiment. Even in this case, since the first fixing member 90A and the second fixing member 90B are arranged at positions where they do not face each other in the X-axis direction, an increase in the size of the power storage element row 29a in the X-axis direction is suppressed.

[0079] Each of the first power storage element 121A and the second power storage element 121B according to this modification example has terminals at both ends in the Y-axis direction. Specifically, the first power storage element 121A includes a first positive electrode terminal 22A disposed at an end in the +Y-axis direction and a first negative electrode terminal 25A disposed at an end in the -Y-axis direction. The second power storage element 121B includes a second positive electrode terminal 22B disposed at an end in the -Y-axis direction and a second negative electrode terminal 25B disposed at an end in the +Y-axis direction. In this modification example, the X-axis direction is an example of the first direction, and the Y-axis direction is an example of the second direction intersecting the first direction. That is, in the first power storage element 121A, the first positive electrode terminal 22A and the first negative electrode terminal 25A are arranged in the second direction, and in the second power storage element 121B, the second positive electrode terminal 22B and the second negative electrode terminal 25B are arranged in the second direction.

[0080] In the first power storage element 121A and the second power storage element 121B configured as described above, the first positive electrode terminal 22A and the second negative electrode terminal 25B are arranged in the X-axis direction, and the first negative electrode terminal 25A and the second positive electrode terminal 22B are arranged in the X-axis direction. Therefore, by connecting the first positive electrode terminal 22A and the second negative electrode terminal 25B, or by connecting the first negative electrode terminal 25A and the second positive electrode terminal 22B, it is easy to connect the first power storage element 121A and the second power storage element 121B in series. Further, when the first power storage element 121A and the second power storage element 121B are connected in series in this way, the distance between the first positive electrode terminal 22A and the second negative electrode terminal 25B, or the distance between the first negative electrode terminal 25A and the second positive electrode terminal 22B, is likely to approach, so that an increase in the electrical resistance at the connection portion between the first power storage element 121A and the second power storage element 121B can be suppressed.

[0081] In this modification example, the positive and negative terminals included in the first power storage element 121A and the second power storage element 121B may be bent in the X-axis direction in the same manner as the positive terminal 22 and the negative terminal 25 according to the embodiment (see FIGS. 2 and 3). That is, at least one of the first positive terminal 22A and the second negative terminal 25B adjacent in the X-axis direction may be bent in a direction approaching the other of the first positive terminal 22A and the second negative terminal 25B. At least one of the first negative terminal 25A and the second positive terminal 22B adjacent in the X-axis direction may be bent in a direction approaching the other of the first negative terminal 25A and the second positive terminal 22B.

[0082] In this modification example, in the Y-axis direction, the first fixing member 90A is disposed on one side in the Y-axis direction from the center Cc of the first electrode body 130A, and the second fixing member 90B is disposed on the other side in the Y-axis direction from the center Cd of the second electrode body 130B. According to this configuration, for example, by rotating one of the two power storage elements 121 of the same model by 180° around an axis parallel to the Z-axis direction and arranging these two power storage elements 121 in the X-axis direction, the first power storage element 121A and the second power storage element 121B can be obtained. For example, by rotating the first power storage element 121A shown in FIG. 9 by 180° around the Z-axis, a power storage element 121 having the same configuration as the second power storage element 121B shown in FIG. 9 can be obtained. Therefore, the power storage device 1 that can be miniaturized can be efficiently manufactured.

[0083] [5. Other Modification Examples] As described above, the power storage device 1 according to the embodiment and its modification examples of the present invention has been described. However, the present invention is not limited to the above-described embodiment and modification examples. The embodiments and modification examples disclosed this time are illustrative in all respects, and the scope of the present invention includes all changes within the meaning and scope equivalent to the claims.

[0084] The first fixing member 90A does not necessarily fix the first outer peripheral portion 34Aa of the first separator 34A to a portion of the first side surface 31A of the first electrode body 30A other than the first outer peripheral portion 34Aa. For example, a double-sided adhesive tape disposed on the first side surface 31A of the first electrode body 30A and fixing the first electrode body 30A to the first exterior film 210A may be employed as the first fixing member 90A. In this case, the double-sided adhesive tape may further serve to fix the first outer peripheral portion 34Aa to a portion of the first side surface 31A other than the first outer peripheral portion 34Aa. These also apply to the second fixing member 90B.

[0085] Joint members other than the double-sided tape 300 may be disposed between the power storage element row 29 and each of the pair of holding members 400, and between two adjacent power storage elements 21 in the X-axis direction in the power storage element row 29. For example, by applying an adhesive to at least one of two adjacent power storage elements 21 in the X-axis direction, the two power storage elements 21 may be joined.

[0086] In the embodiment, as shown in FIG. 8, the center Ca of the first electrode body 30A and the center Cb of the second electrode body 30B are at the same position in the Z-axis direction, but this is not essential. Even if the center Ca of the first electrode body 30A and the center Cb of the second electrode body 30B are at different positions in the Z-axis direction, the increase in the size of the power storage device 1 including the first power storage element 21A and the second power storage element 21B in the X-axis direction is suppressed because the first fixing member 90A and the second fixing member 90B do not face each other in the X-axis direction.

[0087] In the Z-axis direction, it is not essential that the first fixing member 90A is arranged on one side in the Z-axis direction from the center Ca of the first electrode body 30A, and that the second fixing member 90B is arranged on the other side in the Z-axis direction from the center Cb of the second electrode body 30B. For example, when the first fixing member 90A is arranged on one side in the Z-axis direction from the center Ca, the second fixing member 90B may be arranged on one side in the Z-axis direction from the center Cb. That is, if the condition that the first fixing member 90A and the second fixing member 90B do not face each other in the X-axis direction is satisfied, the positional relationship between the first fixing member 90A and the center Ca of the first electrode body 30A in the Z-axis direction is arbitrary, and the positional relationship between the second fixing member 90B and the center Cb of the second electrode body 30B in the Z-axis direction is arbitrary.

[0088] In the Z-axis direction, it is not essential that the first outer peripheral portion 34Aa is arranged on one side in the Z-axis direction from the center Ca of the first electrode body 30A, and that the second outer peripheral portion 34Bb is arranged on the other side in the Z-axis direction from the center Cb of the second electrode body 30B. That is, if the condition that the first fixing member 90A and the second fixing member 90B do not face each other in the X-axis direction is satisfied, the positional relationship between the first outer peripheral portion 34Aa and the center Ca of the first electrode body 30A in the Z-axis direction is arbitrary, and the positional relationship between the second outer peripheral portion 34Bb and the center Cb of the second electrode body 30B in the Z-axis direction is arbitrary.

[0089] It is not essential to connect the first storage element 21A and the second storage element 21B in series. For example, another storage element configured such that the first positive electrode terminal 22A and the second positive electrode terminal 22B are adjacent to each other in the X-axis direction, and the first negative electrode terminal 25A and the second negative electrode terminal 25B are adjacent to each other in the X-axis direction may be adopted as the second storage element 21B. That is, in the second storage element 21B shown in FIG. 7, the positions of the second positive electrode terminal 22B and the second negative electrode terminal 25B may be interchanged. Even in this case, since the first fixing member 90A and the second fixing member 90B do not face each other in the X-axis direction, an increase in the size of the power storage device 1 including the first storage element 21A and the second storage element 21B in the X-axis direction is suppressed. Further, it is easy to connect the first storage element 21A and the second storage element 21B arranged in the X-axis direction in parallel.

[0090] It is not essential to dispose a joining member such as the double-sided tape 300 between each of the battery element row 29 and the pair of holding members 400, and between two adjacent battery elements 21 in the X-axis direction in the battery element row 29. However, for example, from the viewpoints of improving the mechanical strength of the power storage unit 20 (see FIG. 2) including the pair of holding members 400 and the battery element row 29, or improving the positional stability of a plurality of battery elements 21, it is preferable to dispose a joining member such as the double-sided tape 300 between two battery elements 21 or the like. Furthermore, it is more preferable to dispose a joining member such as the double-sided tape 300 between each of the battery element row 29 and the pair of holding members 400.

[0091] In the above embodiment, the case where each of the positive electrode terminal 22 and the negative electrode terminal 25 is bent in the vicinity of the edge of the exterior film 210 has been illustrated (see FIGS. 2 and 3). However, each of the positive electrode terminal 22 and the negative electrode terminal 25 may be bent at a position further away from the vicinity of the edge of the exterior film 210.

[0092] The number of battery elements 21 included in the battery element row 29 is not limited to 4. The battery element row 29 may include two or more battery elements 21 including the first battery element 21A and the second battery element 21B. Thereby, an increase in the size of the battery element row 29 in the X-axis direction is suppressed.

[0093] The supplementary matters regarding the power storage device 1 according to the above embodiment may be applied to the power storage device 1 according to the modification example. A form constructed by arbitrarily combining the constituent elements included in the embodiment and its modification example is also included in the scope of the present invention.

Industrial Applicability

[0094] The present invention can be applied to a power storage device including a power storage element such as a lithium ion secondary battery.

Explanation of Signs

[0095] 1 Power storage device 21, 121 Battery element 21A, 121A First energy storage element 21B, 121B Second energy storage element 22 Positive electrode terminal 22A First positive electrode terminal 22B Second positive electrode terminal 25 Negative electrode terminal 25A First negative electrode terminal 25B Second negative electrode terminal 30 Electrode body 30A, 130A First electrode body 30B, 130B Second electrode body 31A, 131A First side surface 31B, 131B Second side surface 32A First positive electrode plate 32B Second positive electrode plate 33A First negative electrode plate 33B Second negative electrode plate 34A First separator 34Aa First outer peripheral part 34B Second separator 34Bb Second outer peripheral part 90A First fixing member 90B Second fixing member 210 Exterior film 210A First exterior film 210B Second exterior film 219A, 1219A First convex part 219B, 1219B Second convex part

Claims

1. comprising a first energy storage element and a second energy storage element, wherein the first energy storage element comprises a first electrode body, a first fixing member disposed on a first side surface of the first electrode body, and a first outer packaging film for housing the first electrode body and the first fixing member; wherein the second energy storage element comprises a second electrode body, a second fixing member disposed on a second side surface of the second electrode body, and a second outer packaging film for housing the second electrode body and the second fixing member; wherein the first side surface and the second side surface face each other in a first direction, and the first fixing member and the second fixing member do not face each other in the first direction, an energy storage device.

2. wherein the first electrode body comprises a first positive electrode plate, a first negative electrode plate, and a first separator disposed between the first positive electrode plate and the first negative electrode plate; wherein the second electrode body comprises a second positive electrode plate, a second negative electrode plate, and a second separator disposed between the second positive electrode plate and the second negative electrode plate; wherein the first separator comprises a first outer peripheral portion forming a part of the first side surface, and the second separator comprises a second outer peripheral portion forming a part of the second side surface; wherein the first fixing member fixes the first outer peripheral portion to a portion of the first side surface other than the first outer peripheral portion, and the second fixing member fixes the second outer peripheral portion to a portion of the second side surface other than the second outer peripheral portion; the energy storage device according to Claim 1.

3. In a second direction intersecting the first direction, the first fixing member is disposed on one side of the second direction relative to the center of the first electrode body, and the second fixing member is disposed on the other side of the second direction relative to the center of the second electrode body. The power storage device according to claim 2.

4. In the second direction, the first outer peripheral portion is disposed on one side in the second direction from the center of the first electrode body, the second outer peripheral portion is disposed on the other side in the second direction from the center of the second electrode body. The power storage device according to claim 3.

5. The first power storage element includes a first positive electrode terminal and a first negative electrode terminal, the first positive electrode terminal and the first negative electrode terminal are arranged in a second direction intersecting the first direction, the second power storage element includes a second positive electrode terminal and a second negative electrode terminal, the second positive electrode terminal and the second negative electrode terminal are arranged in the second direction, the first positive electrode terminal and the second negative electrode terminal are arranged in the first direction, the first negative electrode terminal and the second positive electrode terminal are arranged in the first direction. The power storage device according to any one of claims 1 to 4.

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