Power storage device

Abstract

To provide a power storage device that can improve the strength of the side walls of a housing frame.SOLUTION: A power storage device includes a power storage element and a case that houses the power storage element, the case includes a first side wall 21 facing a first direction and a second side wall 22 facing a second direction intersecting the first direction, the first side wall includes a pair of first plate-like members 21a facing each other in the first direction and a first connecting member 21b connecting the pair of first plate-like members and extending in a direction perpendicular to the first direction, the second side wall includes a pair of second plate-like members 22a facing each other in the second direction and a second connecting member 22b connecting the pair of second plate-like members and extending in a direction perpendicular to the second direction, and at least one of the first connecting member and the second connecting member extends in a direction different from the first direction X and the second direction Y.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electricity storage device. [Background technology]

[0002] Patent Document 1 discloses a battery pack in which a battery module having a plurality of battery cells is accommodated in a housing. The housing has a frame surrounding the battery module, and the frame includes a vertical wall extending in the vehicle length direction and a horizontal wall extending in the vehicle width direction. Each of the vertical wall and the horizontal wall has a plurality of hollow portions arranged in the vehicle height direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 008064 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned Patent Document 1, since a plurality of hollow portions are provided lined up in the vehicle height direction in each of the vertical wall portions and the horizontal wall portions that are the side walls of the frame of the housing, there is a risk that the strength in the vehicle height direction will be weakened.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and has an object to provide an electricity storage device capable of improving the strength. [Means for solving the problem]

[0006] An energy storage device according to one embodiment of the present invention comprises an energy storage element and a case that houses the energy storage element, the case comprising a first side wall facing a first direction and a second side wall facing a second direction intersecting the first direction, the first side wall comprising a pair of first plate-shaped members facing each other in the first direction and a first connecting member connecting the pair of first plate-shaped members and extending in a direction perpendicular to the first direction, the second side wall comprising a pair of second plate-shaped members facing each other in the second direction and a second connecting member connecting the pair of second plate-shaped members and extending in a direction perpendicular to the second direction, and at least one of the first connecting member and the second connecting member extends in a direction different from the first direction and the second direction. Effect of the Invention

[0007] According to the electricity storage device of the present invention, it is possible to improve the strength. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. [Diagram 2] FIG. 2 is an exploded perspective view showing the inside of the case of the electricity storage device according to the embodiment. [Diagram 3] FIG. 3 is an exploded perspective view illustrating each component of the electricity storage unit according to the embodiment. [Figure 4] FIG. 4 is a perspective view and a top view showing the configuration of a first side wall included in the case according to the embodiment. [Diagram 5] FIG. 5 is a perspective view, a top view, a side view, and a front view showing the configuration of each wall member included in the case according to the embodiment. [Figure 6] FIG. 6 is a perspective view and a top view showing a configuration of a first side wall according to the first modification of the embodiment. [Figure 7] FIG. 7 is a side view showing the configuration of a case according to the second modification of the embodiment. [Figure 8] FIG. 8 is a top view showing a configuration of a first side wall according to the third modification of the embodiment. [Figure 9] FIG. 9 is a top view showing a configuration of a first side wall according to the third modification of the embodiment. [Figure 10] FIG. 10 is a top view showing a configuration of a first side wall according to the third modification of the embodiment. [Figure 11] FIG. 11 is a perspective view showing an external appearance of a power storage device according to a fourth modification of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (1) An energy storage device according to one embodiment of the present invention comprises an energy storage element and a case that houses the energy storage element, the case comprising a first side wall facing a first direction and a second side wall facing a second direction intersecting the first direction, the first side wall comprising a pair of first plate-like members facing each other in the first direction and a first connecting member connecting the pair of first plate-like members and extending in a direction perpendicular to the first direction, the second side wall comprising a pair of second plate-like members facing each other in the second direction and a second connecting member connecting the pair of second plate-like members and extending in a direction perpendicular to the second direction, and at least one of the first connecting member and the second connecting member extends in a direction different from the first direction and the second direction.

[0010] According to an embodiment of the present invention, in the case of the electric storage device, a first side wall facing a first direction includes a first connecting member that connects a pair of first plate-like members facing each other in the first direction, and a second side wall facing a second direction includes a second connecting member that connects a pair of second plate-like members facing each other in the second direction. This allows the first side wall and the second side wall to improve the strength of the electric storage device in the first direction and the second direction. At least one of the first connecting member and the second connecting member extends in a direction different from the first direction and the second direction. This allows the strength of the electric storage device to be improved in a direction different from the first direction and the second direction by at least one of the first connecting member and the second connecting member. Therefore, the strength of the electric storage device can be improved in various directions.

[0011] (2) In the energy storage device described above in (1), the second connecting member may extend in a direction different from a direction in which the first connecting member extends.

[0012] According to the energy storage device described in (2) above, the second connecting member of the second side wall extends in a direction different from the direction in which the first connecting member of the first side wall extends, thereby improving the strength in the direction different from the direction in which the first connecting member extends. This makes it possible to improve the strength of the energy storage device in different directions by the first connecting member and the second connecting member.

[0013] (3) In the energy storage device described in (2) above, the case may further include at least one of a bottom wall and a top wall facing a third direction intersecting the first direction and the second direction, and at least one of the bottom wall and the top wall may include a pair of third plate-like members facing each other in the third direction and a third connecting member connecting the pair of third plate-like members and extending in a direction perpendicular to the third direction, and the third connecting member may extend in a direction different from the extension direction of the first connecting member and the extension direction of the second connecting member.

[0014] According to the energy storage device described in (3) above, at least one of the bottom wall and the top wall facing the third direction is provided with a third connecting member that connects a pair of third plate-like members facing each other in the third direction, thereby improving the strength of the energy storage device in the third direction. Since the third connecting member extends in a direction different from the extending direction of the first connecting member and the extending direction of the second connecting member, the strength of the energy storage device can be improved by the third connecting member also in a direction different from the extending direction of the first connecting member and the extending direction of the second connecting member.

[0015] (4) In the energy storage device according to any one of (1) to (3) above, the first connecting member may be disposed inclined with respect to the first direction.

[0016] According to the electricity storage device described in (4) above, the first connecting member of the first side wall is disposed so as to be inclined with respect to the first direction. This makes it possible to further improve the strength of the first side wall in the first direction.

[0017] (5) In the energy storage device described in any one of (1) to (4) above, the case may further include a connecting member connecting the first side wall to a wall other than the first side wall, and the connecting member may be disposed in a space formed between the pair of first plate-shaped members.

[0018] According to the electricity storage device described above in (5), by disposing the connection member in the space between the pair of first plate-shaped members of the first side wall, the space can be effectively utilized.

[0019] (6) In the energy storage device according to any one of (1) to (5) above, the first side wall may further include a filler disposed in a space formed between the pair of first plate-shaped members.

[0020] According to the electricity storage device described above in (6), by disposing the filler in the space between the pair of first plate-shaped members of the first side wall, the space can be effectively utilized.

[0021] Hereinafter, a description will be given of an energy storage device according to an embodiment (including modified examples) of the present invention with reference to the drawings. The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, the arrangement and connection of the components, manufacturing processes, and the order of the manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. In each drawing, the dimensions are not strictly shown. In each drawing, the same or similar components are given the same reference numerals.

[0022] In the following description and drawings, the X-axis direction is defined as the arrangement direction of a plurality of energy storage elements, the opposing direction of the long side surfaces of the container of one energy storage element, or the direction in which the first side wall of the case of the energy storage device faces. The Y-axis direction is defined as the arrangement direction of a pair of terminals (positive and negative) of one energy storage element, the opposing direction of the short side surfaces of the container of one energy storage element, or the direction in which the second side wall of the case of the energy storage device faces. The Z-axis direction is defined as the arrangement direction of the main body and the lid of the container of the energy storage element, the direction in which the bottom wall and the top wall of the case of the energy storage device face, or the up-down direction. The X-axis direction, the Y-axis direction, and the Z-axis direction intersect with each other (orthogonal in this embodiment). Depending on the mode of use, the Z-axis direction may not be the up-down direction, but for convenience of explanation, the following description will be given assuming that the Z-axis direction is the up-down direction.

[0023] In the following description, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the opposite direction to the positive X-axis direction. When simply referring to the X-axis direction, it refers to both or either of the positive X-axis direction and the negative X-axis direction. When referring to one side and the other side of the X-axis direction, it refers to one and the other of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis direction and the Z-axis direction. Hereinafter, the X-axis direction is also referred to as the first direction, the Y-axis direction is also referred to as the second direction, and the Z-axis direction is also referred to as the third direction. Expressions indicating relative directions or attitudes, such as parallel and perpendicular, include cases where the directions or attitudes are not strictly the same. Two directions being parallel not only mean that the two directions are completely parallel, but also mean that the directions are substantially parallel, that is, that there is a difference of about a few percent. In the following description, when the word "insulation" is used, it means "electrical insulation". An insulating material has a volume resistivity of 1×10 10 It is preferable that the material used is one having a resistance of Ωm or higher.

[0024] (Embodiment) [1 General Description of Energy Storage Device 1] First, an overall description of the energy storage device 1 according to the present embodiment will be given. Fig. 1 is a perspective view showing the external appearance of the energy storage device 1 according to the present embodiment. Fig. 2 is a perspective view showing the inside of the case 20 of the energy storage device 1 according to the present embodiment, with the case 20 disassembled. Fig. 2 shows the external appearance of the energy storage unit 10 disposed inside the case 20. Fig. 3 is an exploded perspective view showing each component when the energy storage unit 10 according to the present embodiment is disassembled.

[0025] The power storage device 1 is a device that can charge electricity from the outside and discharge electricity to the outside, and in this embodiment, has a rectangular parallelepiped shape. A rectangular parallelepiped is a hexahedron with all faces formed of rectangles or squares. The power storage device 1 is used for power storage or power supply. Specifically, the power storage device 1 is used as a battery for driving or starting an engine of 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: Automatic Guided Vehicle), or a railway vehicle for an electric railway. Examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. Examples of the above-mentioned railway vehicles for an electric railway include electric trains, monorails, linear motor cars, and hybrid trains equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0026] 1 and 2, the energy storage device 1 includes an energy storage unit 10 and a case 20 that houses the energy storage unit 10. The energy storage device 1 also includes an external terminal that is connected to a conductive member outside the case 20, and a bus bar or a cable that connects the external terminal to the energy storage unit 10, but these are not shown or described. In addition to the above configuration, the energy storage device 1 may also include an exhaust section for exhausting gas discharged from the energy storage unit 10 to the outside of the case 20.

[0027] [1.1 Description of the storage unit 10] The energy storage unit 10 is a battery module (battery assembly) having a substantially rectangular parallelepiped shape that can be charged with electricity from the outside and can discharge electricity to the outside. As shown in Fig. 2 and Fig. 3, the energy storage unit 10 includes a case 100, and a plurality of energy storage elements 200, a bus bar 300, and the like are housed inside the case 100. In addition to the above configuration, the energy storage unit 10 may include spacers arranged between the plurality of energy storage elements 200, restraining members (side plates, end plates, etc.) that restrain the plurality of energy storage elements 200, a bus bar holder that holds the bus bar 300, a circuit board that monitors or controls the charging state and discharging state of the energy storage elements 200, electrical components such as relays, fuses, shunt resistors, and connectors, an exhaust unit that exhausts gas discharged from the energy storage elements 200 to the outside of the case 100, and the like.

[0028] The case 100 is a container (module case) having a substantially rectangular parallelepiped (box-shaped) shape that constitutes the exterior body (housing, outer shell) of the energy storage unit 10. The case 100 constitutes the inner case of the energy storage device 1. The case 100 is disposed outside the multiple energy storage elements 200 and the bus bars 300, etc., and fixes the energy storage elements 200, etc. at predetermined positions to protect them from impacts and the like. The case 100 is formed of an insulating material 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 or the like with an insulating coating. This prevents the energy storage element 200 and the like from coming into contact with external metal members and the like. The case 100 may be formed of a metal when an insulation distance between the energy storage element 200 and the external metal members is appropriately set.

[0029] The case 100 includes a case main body 110 constituting the main body of the case 100, and a case lid 120 constituting the lid of the case 100. The case main body 110 and the case lid 120 are joined together by adhesive, heat sealing, ultrasonic welding, or screwing with bolts. This gives the case 100 a structure in which the inside is sealed (sealed). The case main body 110 and the case lid 120 may be formed from members of the same material or from members of different materials.

[0030] The case body 110 is a bottomed rectangular cylindrical housing (chassis) with an opening formed in the positive direction of the Z axis, and houses the energy storage element 200 and the like. The case body 110 has a pair of flat, rectangular short side walls 111 on both sides in the X axis direction, a pair of flat, rectangular long side walls 112 on both sides in the Y axis direction, and a flat, rectangular bottom wall 113 in the negative direction of the Z axis. Depending on the configuration of the contents of the case body 110, the long side walls, short side walls and bottom wall may have any shape.

[0031] The case lid 120 is a flat rectangular member that closes the opening of the case body 110. The case lid 120 is provided with a positive electrode terminal 121 and a negative electrode terminal 122, which are external terminals (terminals) for connecting to the outside of the power storage unit 10. The power storage unit 10 is charged with electricity from the outside and discharges electricity to the outside via the positive electrode terminal 121 and the negative electrode terminal 122.

[0032] The energy storage element 200 is a secondary battery (single cell) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The energy storage element 200 has a flattened rectangular parallelepiped shape (angle, rectangular shape) in the X-axis direction, and in this embodiment, eight energy storage elements 200 are arranged in the X-axis direction. The size, shape, and number of the energy storage elements 200 to be arranged are not limited, and the energy storage element 200 may have a cylindrical shape (cylinder shape), an elongated cylindrical shape, an elliptical cylindrical shape, a polygonal prism shape other than a rectangular parallelepiped, or the like, or only one energy storage element 200 may be arranged. The energy storage element 200 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 energy storage element 200 may be a primary battery instead of a secondary battery. The energy storage element 200 may be a battery using a solid electrolyte. The energy storage element 200 may be a pouch-type energy storage element.

[0033] The energy storage element 200 includes a container 210 and a pair of terminals 220 (positive and negative electrodes). An electrode body, a pair of current collectors (positive and negative electrodes), and an electrolyte (non-aqueous electrolyte) are contained inside the container 210, and a gasket is disposed between the container 210 and the terminals 220 and current collectors, but these are not shown in the figure. There is no particular limit to the type of electrolyte as long as it does not impair the performance of the energy storage element 200, and various electrolytes can be selected. In addition to the above-mentioned components, the energy storage element 200 may include a spacer disposed on the side or below the electrode body, an insulating film that wraps the electrode body, or an insulating film (shrink tube, etc.) that covers the outer surface of the container 210.

[0034] The container 210 is a rectangular parallelepiped (angular or box-shaped) container including a container body 211 with an opening formed therein and a container lid 212 that closes the opening of the container body 211. The container body 211 has a pair of long side surfaces on both sides in the X-axis direction, a pair of short side surfaces on both sides in the Y-axis direction, and a bottom surface in the negative Z-axis direction, and the container lid 212 is disposed at the end of the container body 211 in the positive Z-axis direction. The container lid 212 is provided with a gas exhaust valve 213 that releases pressure when the pressure inside the container 210 rises excessively, and a liquid injection part (not shown) for injecting an electrolyte into the container 210. The material of the container 210 is not particularly limited, and may be a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel plate, but resin may also be used.

[0035] The terminals 220 are electrode terminals (positive and negative terminals) of the energy storage element 200, which are disposed on the container lid portion 212. The terminals 220 are disposed protruding from the container lid portion 212 in the positive direction of the Z axis. The terminals 220 are electrically connected to the positive and negative plates of the electrode body via a current collector. The terminals 220 are metal members for conducting electricity stored in the electrode body to the external space of the energy storage element 200 and for introducing electricity into the internal space of the energy storage element 200 in order to store electricity in the electrode body. The terminals 220 are formed of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

[0036] The electrode body is an electric storage element (power generating element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is a current collector foil made of a metal such as aluminum or an aluminum alloy, on which a positive electrode active material layer is formed. The negative electrode plate is a current collector foil made of a metal such as copper or a copper alloy, on which a negative electrode active material layer is formed. As the active material used in the positive electrode active material layer and the negative electrode active material layer, any known material can be used as long as it can absorb and release charge transport ions. The separator can be a microporous sheet or nonwoven fabric made of resin. In this embodiment, the electrode body is formed by laminating electrode plates (positive electrode plate and negative electrode plate) in the X-axis direction. The electrode body may be any type of electrode body, such as a wound type electrode body formed by winding electrode plates (positive electrode plate and negative electrode plate), a stack type electrode body formed by stacking a plurality of flat electrode plates, or a bellows type electrode body in which the electrode plates are folded in a bellows shape.

[0037] The current collectors are conductive current collecting members (positive and negative current collectors) electrically connected to the terminal 220 and the electrode body. The positive current collector is made of aluminum or an aluminum alloy, etc., like the current collecting foil of the positive electrode plate of the electrode body, and the negative current collector is made of copper or a copper alloy, etc., like the current collecting foil of the negative electrode plate of the electrode body. The gasket is disposed between the container lid 212 and the terminal 220 and the current collectors, and insulates and seals between the container lid 212 and the terminal 220 and the current collectors. The gasket may be made of any material as long as it has insulating properties.

[0038] The bus bar 300 is a plate-like member connected to the energy storage elements 200. The bus bar 300 is disposed above the energy storage elements 200, and is connected (joined) to terminals 220 provided on the energy storage elements 200. Specifically, the bus bar 300 connects the terminals 220 of the energy storage elements 200 to each other, and electrically connects the terminals 220 of the energy storage elements 200 at the ends to the positive electrode terminal 121 and the negative electrode terminal 122. The bus bar 300 is formed of a conductive member made of metal such as aluminum, an aluminum alloy, copper, a copper alloy, or nickel, or a combination thereof, or a conductive member other than a metal.

[0039] The bus bar 300 includes bus bars 310, 320, and 330. The bus bar 330 connects two energy storage elements 200 in parallel to form four sets of energy storage element groups, and connects the four sets of energy storage element groups in series. The bus bar 310 is connected to the terminals 220 (positive electrode terminals) of two energy storage elements 200 in the energy storage element group arranged at the end in the positive direction of the X axis, and is connected to the positive electrode general terminal 121 via another bus bar or the like. The bus bar 320 is connected to the terminals 220 (negative electrode terminals) of two energy storage elements 200 in the energy storage element group arranged at the end in the negative direction of the X axis, and is connected to the negative electrode general terminal 122 via another bus bar or the like. The connection form of the bus bar 300 is not particularly limited, and a plurality of energy storage elements 200 may be connected in series in any combination or in parallel, or all of the energy storage elements 200 may be connected in series or in parallel. In the present embodiment, bus bar 300 and terminal 220 are joined by welding, but may also be joined by bolting or by other methods.

[0040] [1.2 Explanation of Case 20] The case 20 is a rectangular parallelepiped (box-shaped) container (outer case) constituting the outer case (exterior body, housing, outer shell) of the energy storage device 1. The case 20 is a protective frame (outer frame) disposed outside the energy storage unit 10 to house the energy storage unit 10, fix the energy storage unit 10 at a predetermined position, and protect it from impact and the like. In the present embodiment, the case 20 houses one energy storage unit 10. The case 20 is a metal case formed of a metal member such as aluminum, aluminum alloy, stainless steel, iron, plated steel sheet, or the like. The case 20 may be formed of an insulating member such as any resin material that can be used for the case 100 of the energy storage unit 10.

[0041] As shown in Figures 1 and 2, the case 20 has a pair of first side walls 21 facing each other in the X-axis direction, a pair of second side walls 22 facing each other in the Y-axis direction, and a bottom wall 23 and a top wall 24 facing each other in the Z-axis direction.

[0042] The pair of first side walls 21 are flat, rectangular wall members arranged parallel to the YZ plane in an attitude facing the X-axis direction (first direction) at both ends of the case 20 in the X-axis direction. The pair of first side walls 21 are side walls (short side walls) of the case 20 arranged opposite to the short side walls 111 of the case body 110 of the case 100 on both sides in the X-axis direction of the electricity storage unit 10. In the present embodiment, the pair of first side walls 21 have the same configuration.

[0043] The pair of second side walls 22 are flat, rectangular members arranged parallel to the XZ plane at both ends in the Y axis direction of the case 20 and facing the Y axis direction (a second direction intersecting the first direction). The pair of second side walls 22 are side walls (long side walls) of the case 20 arranged opposite the long side walls 112 of the case body 110 of the case 100 on both sides in the Y axis direction of the electricity storage unit 10. In the present embodiment, the pair of second side walls 22 have the same configuration.

[0044] The bottom wall 23 is a flat, rectangular member disposed at the end of the case 20 in the negative Z-axis direction in parallel to the XY plane in a position facing the Z-axis direction (a third direction intersecting the first direction and the second direction). The bottom wall 23 is the bottom wall of the case 20 disposed opposite the bottom wall 113 of the case body 110 of the case 100 in the negative Z-axis direction of the power storage unit 10. The upper wall 24 is a flat, rectangular member disposed at the end of the case 20 in the positive Z-axis direction in parallel to the XY plane in a position facing the Z-axis direction (a third direction). The upper wall 24 is the upper wall of the case 20 disposed opposite the case cover 120 of the case 100 in the positive Z-axis direction of the power storage unit 10. In this way, the case 20 includes at least one of the bottom wall 23 and the upper wall 24 (both in this embodiment). In this embodiment, the bottom wall 23 and the upper wall 24 have the same configuration.

[0045] Thus, the case 20 has six walls (a pair of first side walls 21, a pair of second side walls 22, a bottom wall 23, and an upper wall 24). These six walls are connected (joined) by welding, bolting, adhesive, or the like. After connecting (joining) the pair of first side walls 21, the pair of second side walls 22, and the bottom wall 23 by welding and accommodating the electricity storage unit 10, the remaining wall (the upper wall 24) is connected (joined) to another wall (a wall other than the remaining wall) by bolting, so that the case 20 can be formed. These six walls may be formed of members of the same material or of different materials. Depending on the configuration (number, size, shape, etc.) of the contents of the case 20, the case 20 (the first side wall 21, the second side wall 22, the bottom wall 23, and the upper wall 24) may have any shape. In this case, the first side wall 21 may be a long side wall, and the second side wall 22 may be a short side wall. The configuration of each wall member (first side wall 21, second side wall 22, bottom wall 23, and top wall 24) of the case 20 will be described in detail below.

[0046] [2. Description of each wall member of the case 20] FIG. 4 is a perspective view and a top view showing the configuration of the first side wall 21 included in the case 20 according to this embodiment. FIG. 4(a) is an enlarged perspective view of the first side wall 21 shown in FIG. 2, and FIG. 4(b) is a top view showing the configuration of the first side wall 21 of FIG. 4(a) when viewed from the Z-axis positive direction. FIG. 5 is a perspective view, a top view, a side view, and a front view showing the configuration of each wall member included in the case 20 according to this embodiment. FIG. 5(a) is a perspective view showing a state in which the first side wall 21 and the upper wall 24 are separated from the case 20. FIG. 5(b) is a top view showing the configuration of a part of the first side wall 21 when viewed from the Z-axis positive direction. FIG. 5(c) is a side view showing the configuration of a part of the second side wall 22 when viewed from the X-axis positive direction. FIG. 5(d) is a front view showing the configuration of a part of the bottom wall 23 when viewed from the Y-axis negative direction. FIG. 5(e) is a front view showing a configuration of a part of the upper wall 24 when viewed from the negative Y-axis direction.

[0047] [2.1 Description of the first side wall 21] As shown in FIG. 4, the first side wall 21 includes a pair of first plate-like members 21a and a first connecting member 21b. The pair of first plate-like members 21a are flat, rectangular portions disposed at both ends of the first side wall 21 in the X-axis direction and parallel to the YZ plane in a posture facing the X-axis direction. As a result, the pair of first plate-like members 21a face each other in the X-axis direction (first direction). The first connecting member 21b is a portion that connects the pair of first plate-like members 21a. In this embodiment, the first connecting member 21b is a flat portion parallel to the XZ plane, and both ends of the first connecting member 21b in the X-axis direction are connected to the pair of first plate-like members 21a, so that the first connecting member 21b connects (connects) the pair of first plate-like members 21a. The first connecting member 21b extends in a direction perpendicular to the X-axis direction (first direction). In this embodiment, the first connecting member 21b is an elongated portion that extends in the Z-axis direction. The first side wall 21 includes a plurality of first connecting members 21b arranged in the Y-axis direction, and these first connecting members 21b connect the pair of first plate-shaped members 21a.

[0048] With this configuration, a space 21c is formed between the pair of first plate-like members 21a in the first side wall 21. The space 21c is a space surrounded by the pair of first plate-like members 21a and the two first connecting members 21b. In this embodiment, the space 21c is a rectangular space extending in the Z-axis direction when viewed from the Z-axis direction, and penetrates the first side wall 21 in the Z-axis direction. The first side wall 21 is formed with a plurality of spaces 21c aligned in the Y-axis direction.

[0049] As described above, the pair of first side walls 21 of the case 20 have the same configuration. That is, each of the pair of first side walls 21 includes a pair of first plate-shaped members 21a and a plurality of first connecting members 21b shown in FIG. 4, and a plurality of spaces 21c are formed. The pair of first side walls 21 are disposed on both sides of the pair of second side walls 22 in the X-axis direction, and sandwich the pair of second side walls 22. The pair of first side walls 21 are disposed between the bottom wall 23 and the upper wall 24 in the Z-axis direction, and are sandwiched between the bottom wall 23 and the upper wall 24. As a result, the plurality of spaces 21c are closed by the bottom wall 23 and the upper wall 24. In this embodiment, the first side wall 21 is an aluminum extrusion molded product formed by aluminum extrusion processing.

[0050] 5, the second side wall 22, the bottom wall 23 and the upper wall 24 each include a pair of plate-like members and a connecting member that connects the pair of plate-like members, similar to the first side wall 21. The configurations of the second side wall 22, the bottom wall 23 and the upper wall 24 will be described in detail below.

[0051] [2.2 Description of the second side wall 22] As shown in FIG. 5(c), the second side wall 22 includes a pair of second plate-like members 22a and a second connecting member 22b. The pair of second plate-like members 22a are flat, rectangular portions disposed parallel to the XZ plane in a posture facing the Y-axis direction at both ends of the second side wall 22 in the Y-axis direction. As a result, the pair of second plate-like members 22a face each other in the Y-axis direction (second direction). The second connecting member 22b is a portion that connects the pair of second plate-like members 22a. In this embodiment, the second connecting member 22b is a flat portion parallel to the XY plane, and the second connecting member 22b connects (connects) the pair of second plate-like members 22a by connecting both ends of the second connecting member 22b in the Y-axis direction to the pair of second plate-like members 22a. The second connecting member 22b extends in a direction perpendicular to the Y-axis direction (second direction). In this embodiment, the second connecting member 22b is an elongated portion that extends in the X-axis direction. The second side wall 22 includes a plurality of second connecting members 22b arranged in the Z-axis direction, and these second connecting members 22b connect the pair of second plate-shaped members 22a.

[0052] In this manner, since the first connecting member 21b extends in the Z-axis direction and the second connecting member 22b extends in the X-axis direction, the second connecting member 22b extends in a direction different from the extension direction of the first connecting member 21b. Furthermore, at least one of the first connecting member 21b and the second connecting member 22b extends in a direction different from the X-axis direction (first direction) and the Y-axis direction (second direction). In this embodiment, the first connecting member 21b extends in a direction different from the X-axis direction (first direction) and the Y-axis direction (second direction).

[0053] With this configuration, a space 22c is formed between the pair of second plate-like members 22a in the second side wall 22. The space 22c is a space surrounded by the pair of second plate-like members 22a and the two second connecting members 22b. In this embodiment, the space 22c is a rectangular space extending in the X-axis direction when viewed from the X-axis direction, and penetrates the second side wall 22 in the X-axis direction. The second side wall 22 is formed with a plurality of spaces 22c aligned in the Z-axis direction.

[0054] As described above, the pair of second side walls 22 of the case 20 have the same configuration. That is, each of the pair of second side walls 22 includes a pair of second plate-shaped members 22a and a plurality of second connecting members 22b, and a plurality of spaces 22c are formed. The pair of second side walls 22 are disposed between the pair of first side walls 21 in the X-axis direction and are sandwiched between the pair of first side walls 21. The pair of second side walls 22 are disposed between the bottom wall 23 and the upper wall 24 in the Z-axis direction and are sandwiched between the bottom wall 23 and the upper wall 24. As a result, the plurality of spaces 22c are blocked by the pair of first side walls 21. In this embodiment, the second side wall 22 is an aluminum extrusion molded product formed by aluminum extrusion processing, similar to the first side wall 21.

[0055] [2.3 Description of bottom wall 23 and top wall 24] As shown in FIG. 5(d), the bottom wall 23 includes a pair of third plate-like members 23a and a third connecting member 23b. The pair of third plate-like members 23a are flat, rectangular portions disposed at both ends of the bottom wall 23 in the Z-axis direction and parallel to the XY plane in a posture facing the Z-axis direction. As a result, the pair of third plate-like members 23a face each other in the Z-axis direction (third direction). The third connecting member 23b is a portion that connects the pair of third plate-like members 23a. In this embodiment, the third connecting member 23b is a flat portion parallel to the YZ plane, and both ends of the third connecting member 23b in the Z-axis direction are connected to the pair of third plate-like members 23a, so that the third connecting member 23b connects (connects) the pair of third plate-like members 23a. The third connecting member 23b extends in a direction perpendicular to the Z-axis direction (third direction). In this embodiment, the third connecting member 23b is an elongated portion that extends in the Y-axis direction. The bottom wall 23 includes a plurality of third connecting members 23b arranged in the X-axis direction, and these third connecting members 23b connect the pair of third plate-shaped members 23a.

[0056] In this way, the first connecting member 21b extends in the Z-axis direction, the second connecting member 22b extends in the X-axis direction, and the third connecting member 23b extends in the Y-axis direction, so that the third connecting member 23b extends in a direction different from the extension direction of the first connecting member 21b and the extension direction of the second connecting member 22b.

[0057] With this configuration, a space 23c is formed between the pair of third plate-like members 23a in the bottom wall 23. The space 23c is a space surrounded by the pair of third plate-like members 23a and the two third connecting members 23b. In this embodiment, the space 23c is a rectangular space extending in the Y-axis direction when viewed from the Y-axis direction, and penetrates the bottom wall 23 in the Y-axis direction. A plurality of spaces 23c aligned in the X-axis direction are formed in the bottom wall 23.

[0058] As shown in FIG. 5(e), the upper wall 24 includes a pair of third plate-like members 24a and a third connecting member 24b, similar to the bottom wall 23. The pair of third plate-like members 24a are flat, rectangular portions disposed at both ends of the upper wall 24 in the Z-axis direction and parallel to the XY plane in a posture facing the Z-axis direction. As a result, the pair of third plate-like members 24a face each other in the Z-axis direction (third direction). The third connecting member 24b is a portion that connects the pair of third plate-like members 24a. In this embodiment, the third connecting member 24b is a flat portion parallel to the YZ plane, and the both ends of the third connecting member 24b in the Z-axis direction are connected to the pair of third plate-like members 24a, so that the third connecting member 24b connects (connects) the pair of third plate-like members 24a. The third connecting member 24b extends in a direction perpendicular to the Z-axis direction (third direction). In the present embodiment, the third connecting member 24b is an elongated portion extending in the Y-axis direction. The upper wall 24 includes a plurality of third connecting members 24b arranged in the X-axis direction, and these third connecting members 24b connect the pair of third plate-like members 24a.

[0059] In this way, the first connecting member 21b extends in the Z-axis direction, the second connecting member 22b extends in the X-axis direction, and the third connecting member 24b extends in the Y-axis direction, so that the third connecting member 24b extends in a direction different from the extension direction of the first connecting member 21b and the extension direction of the second connecting member 22b.

[0060] With this configuration, a space 24c is formed between the pair of third plate-like members 24a in the upper wall 24. The space 24c is a space surrounded by the pair of third plate-like members 24a and the two third connecting members 24b. In this embodiment, the space 24c is a rectangular space extending in the Y-axis direction when viewed from the Y-axis direction, and penetrates the upper wall 24 in the Y-axis direction. A plurality of spaces 24c aligned in the X-axis direction are formed in the upper wall 24.

[0061] Thus, at least one of the bottom wall 23 and the upper wall 24 includes a pair of third plate-shaped members and a third connecting member. As described above, the bottom wall 23 and the upper wall 24 have the same configuration. That is, both the bottom wall 23 and the upper wall 24 include a pair of third plate-shaped members and a plurality of third connecting members, and a plurality of spaces are formed. The bottom wall 23 and the upper wall 24 are disposed on both sides of the pair of first side walls 21 and the pair of second side walls 22 in the Z-axis direction, and sandwich the pair of first side walls 21 and the pair of second side walls 22. As a result, the plurality of spaces 23c and the plurality of spaces 24c are open in the Y-axis direction without being blocked by the pair of first side walls 21 and the pair of second side walls 22. In this embodiment, the bottom wall 23 and the upper wall 24 are aluminum extrusion molded products formed by aluminum extrusion processing, similar to the first side walls 21, etc.

[0062] [3 Explanation of effects] As described above, according to the energy storage device 1 according to the embodiment of the present invention, in the case 20, the first side wall 21 facing the X-axis direction (first direction) includes the first connecting member 21b connecting a pair of first plate-like members 21a facing each other in the X-axis direction (first direction). The second side wall 22 facing the Y-axis direction (second direction) includes the second connecting member 22b connecting a pair of second plate-like members 22a facing each other in the Y-axis direction (second direction). This allows the first side wall 21 and the second side wall 22 to improve the strength of the energy storage device 1 in the X-axis direction (first direction) and the Y-axis direction (second direction). At least one of the first connecting member 21b and the second connecting member 22b (in this embodiment, the first connecting member 21b) extends in a direction different from the X-axis direction (first direction) and the Y-axis direction (second direction) (in this embodiment, the Z-axis direction). As a result, at least one of the first connecting member 21b and the second connecting member 22b (in this embodiment, the first connecting member 21b) can improve the strength of the energy storage device 1 in a direction (in this embodiment, the Z-axis direction) different from the X-axis direction (first direction) and the Y-axis direction (second direction). Therefore, the strength of the energy storage device 1 can be improved (improved load-bearing capacity) in various directions.

[0063] As a result, the shock resistance of the electricity storage device 1 (case 20) from various directions can be improved. Since the first side wall 21 is configured such that the pair of first plate-shaped members 21a are connected by the first connecting member 21b, a space 21c is formed between the pair of first plate-shaped members 21a. This allows the weight of the electricity storage device 1 to be reduced. By providing the first connecting member 21b on the first side wall 21 (forming the space 21c), the area of ​​the first side wall 21 is increased, thereby improving heat dissipation (the first connecting member 21b can be used as a heat dissipation fin). These effects of the first side wall 21 can be similarly applied to the second side wall 22, the bottom wall 23, and the top wall 24.

[0064] The second connecting member 22b of the second side wall 22 extends in a direction (in this embodiment, the X-axis direction) different from the extension direction of the first connecting member 21b of the first side wall 21 (in this embodiment, the Z-axis direction), thereby improving the strength in the direction different from the extension direction of the first connecting member 21b. This makes it possible to improve the strength of the electricity storage device 1 in mutually different directions (in this embodiment, the Z-axis direction and the X-axis direction) by the first connecting member 21b and the second connecting member 22b.

[0065] At least one of the bottom wall 23 and the upper wall 24 (both in this embodiment) facing the Z-axis direction (third direction) is provided with a third connecting member that connects a pair of third plate-like members facing each other in the Z-axis direction (third direction). In this embodiment, the bottom wall 23 is provided with a third connecting member 23b that connects a pair of third plate-like members 23a facing each other in the Z-axis direction (third direction). The upper wall 24 is provided with a third connecting member 24b that connects a pair of third plate-like members 24a facing each other in the Z-axis direction (third direction). This can improve the strength of the electricity storage device 1 in the Z-axis direction (third direction). At least one of the third connecting member 23b and the third connecting member 24b (both in this embodiment) extends in a direction different from the extension direction of the first connecting member 21b and the extension direction of the second connecting member 22b (Y-axis direction in this embodiment). Therefore, at least one of the third connecting members 23b and 24b (in this embodiment, both) can improve the strength of the energy storage device 1 in the extension direction of the first connecting member 21b and in a direction different from the extension direction of the second connecting member 22b (in this embodiment, the Z-axis direction).

[0066] [4 Explanation of Modifications] Although the energy storage device 1 according to the present embodiment has been described above, the present invention is not limited to the above embodiment. The embodiment disclosed herein is illustrative and not restrictive in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0067] (Variation 1) In the above embodiment, the space 21c formed in the first side wall 21 of the case 20 is hollow, but a filler may be disposed in the space 21c. Fig. 6 is a perspective view and a top view showing the configuration of the first side wall 21A according to the first modification of the present embodiment. Fig. 6 is a view corresponding to Fig. 4. That is, Fig. 6(a) is a perspective view corresponding to Fig. 4(a), and Fig. 6(b) is a top view corresponding to Fig. 4(b).

[0068] As shown in FIG. 6, the first side wall 21A in this modification has a filler 21d disposed in the space 21c formed in the first side wall 21 in the above embodiment. That is, the first side wall 21A in this modification further includes a filler 21d disposed in the space 21c formed between a pair of first plate-like members 21a in addition to the configuration of the first side wall 21 in the above embodiment. The filler 21d is a heat insulating material such as urethane foam, or a relatively high-strength member such as resin or concrete. In this modification, the filler 21d is disposed (filled) in the entire region of all the spaces 21c, but in any of the spaces 21c, the filler 21d may not be disposed in a part or the entire region. The other configurations of this modification are the same as those of the above embodiment, and therefore detailed description thereof will be omitted.

[0069] As described above, according to this modification, the same effects as those of the above-mentioned embodiment are achieved. In particular, in this modification, the filler 21d is disposed in the space 21c between the pair of first plate-like members 21a of the first side wall 21A, so that the space 21c can be effectively utilized. By filling the space 21c with a heat insulating material such as urethane foam as the filler 21d, the heat insulating property of the first side wall 21A can be improved. By filling the space 21c with a relatively high-strength member such as resin or concrete as the filler 21d, the strength of the first side wall 21A can be further improved.

[0070] In this modification, various materials other than those mentioned above can be used as the filler 21d. The filler 21d may be disposed in only one of the pair of first side walls 21A. In addition to the first side wall 21A, or instead of the first side wall 21A, a filler may be disposed in another wall (a wall other than the first side wall 21A). That is, a filler may be disposed in the space 22c of the second side wall 22, the space 23c of the bottom wall 23, or the space 24c of the top wall 24.

[0071] (Variation 2) In the above-mentioned modification 1, the filler 21d is arranged in the space 21c, but various members other than the filler 21d can be arranged in the space 21c. An example will be described below. Fig. 7 is a side view showing the configuration of the case 20A according to the modification 2 of the present embodiment. Fig. 7 is a view of the case 20A as viewed from the positive direction of the X-axis.

[0072] 7, case 20A in this modification has a configuration in which first side wall 21 of case 20 in the above embodiment and walls other than first side wall 21 (bottom wall 23 and top wall 24) are connected (joined) by connecting member 25. That is, case 20A in this modification further includes, in addition to case 20 in the above embodiment, connecting member 25 that connects first side wall 21 and walls other than first side wall 21 (bottom wall 23 and top wall 24). Connecting member 25 is disposed in space 21c formed between a pair of first plate-shaped members 21a of first side wall 21.

[0073] Specifically, the connection member 25 is a long bolt (long bolt) and a nut, and the shaft portion of the long bolt penetrates the space 21c of the first side wall 21, and the head portion and the nut of the long bolt are disposed in the space 23c of the bottom wall 23 and the space 24c of the upper wall 24. Two connection members 25 are disposed at both ends in the Y-axis direction of the first side wall 21, the bottom wall 23, and the upper wall 24. The first side wall 21 is connected (joined) to the bottom wall 23 and the upper wall 24 by the connection members 25. In order to dispose the connection members 25, through holes and the like are formed in the third plate-like member 23a of the bottom wall 23 and the third plate-like member 24a of the upper wall 24, but illustrations and detailed descriptions of these are omitted. The other configurations of this modified example are the same as those of the above embodiment, and detailed descriptions thereof are omitted.

[0074] As described above, this modification provides the same effects as the above-described embodiment. In particular, in this modification, the connection member 25 is disposed in the space 21c between the pair of first plate-like members 21a of the first side wall 21, so that the space 21c can be effectively utilized. By using a long bolt as the connection member 25 and passing the long bolt through the space 21c, the strength can also be improved by the long bolt. By connecting the walls with the connection member 25, there is no need to connect them by welding or the like, which contributes to space saving and improved assembly of the electricity storage device 1.

[0075] In this modification, walls other than those described above may also be connected to each other by the connecting member 25. A short bolt may be used as the connecting member 25 instead of a long bolt. In this case, the Z-axis direction end of the space 21c of the first side wall 21 may be made solid to form a female thread, and the connecting member 25 may be screwed into this female thread. The connecting member 25 may be used to fix the case 20A to a member on which the case 20A is installed (such as a member on which the case 20A is installed in a vehicle).

[0076] (Variation 3) In the above embodiment, the first connecting member 21b of the first side wall 21 is arranged parallel to the XZ plane (parallel to the X-axis direction), but it may be arranged inclined with respect to the X-axis direction. Figures 8 to 10 are top views showing the configurations of the first side walls 21B to 21D according to Modification 3 of this embodiment. Figures 8 to 10 are views corresponding to (b) of Figure 4.

[0077] As shown in FIG. 8, the first side wall 21B in this modification has a configuration in which a first connecting member 21e and a first connecting member 21f are added to the first side wall 21 in the above embodiment. The first connecting member 21e and the first connecting member 21f are arranged at an incline with respect to the X-axis direction (first direction). Specifically, the first connecting member 21e is provided in each of the spaces 21c formed in the negative Y-axis direction from the center of the first side wall 21B in the Y-axis direction, and the first connecting member 21f is provided in each of the spaces 21c formed in the positive Y-axis direction from the center of the first side wall 21B in the Y-axis direction. Each space 21c is divided into two spaces (triangular spaces as viewed from the Z-axis direction) by the first connecting member 21e and the first connecting member 21f. The first connecting member 21e is arranged at an incline with respect to the X-axis direction so as to be inclined in the negative Y-axis direction as it approaches the positive X-axis direction. The first connecting member 21f is arranged at an incline with respect to the X-axis direction so as to be inclined in the positive Y-axis direction as it approaches the positive X-axis direction. The other configuration of this modification is similar to that of the above embodiment, so detailed description will be omitted.

[0078] 9, the first side wall 21C in this modification has a configuration in which the first connecting members 21e and the first connecting members 21f included in the first side wall 21B described above are arranged alternately. That is, the first connecting members 21e and the first connecting members 21f are arranged alternately in a plurality of spaces 21c arranged in the Y-axis direction. As a result, the V-shaped first connecting members 21e and the first connecting members 21f are arranged in the Y-axis direction. The other configurations of the first side wall 21C are similar to those of the first side wall 21B described above, and therefore detailed description thereof will be omitted.

[0079] 10, the first side wall 21D in this modification has a configuration in which the first connecting member 21b is removed from the first side wall 21C described above. That is, the first side wall 21D has a configuration in which the V-shaped first connecting member 21e and the first connecting member 21f are arranged in the Y-axis direction. As a result, the space 21c becomes a triangular space when viewed from the Z-axis direction. The other configurations of the first side wall 21D are the same as those of the first side wall 21C described above, and therefore detailed description will be omitted.

[0080] As described above, this modification provides the same effects as the above-described embodiment. In particular, in this modification, the first connecting members 21e and 21f of the first side walls 21B to 21D are arranged inclined with respect to the X-axis direction (first direction) to form a truss structure. This can further improve the strength (strength against compression and bending) of the first side walls 21B to 21D in the X-axis direction (first direction). The strength (strength against compression and bending) is defined as follows. In the case of compressive strength, when pressure is applied uniformly to the surface of the first side walls 21B to 21D facing the X-axis direction (first direction), the smaller the change in thickness of the first side walls 21B to 21D in the X-axis direction, the greater the strength. In terms of bending strength, when pressure is applied to the center of the first side walls 21B to 21D in the Y-axis direction and on a straight line from one end to the other end of the first side walls 21B to 21D in the Z-axis direction among the surfaces of the first side walls 21B to 21D facing the X-axis direction (first direction), the strength is greater as the deformation amount of the first side walls 21B to 21D in the X-axis direction is smaller.

[0081] In this modification, the angle of inclination of the first connecting member 21e and the first connecting member 21f with respect to the X-axis direction is not particularly limited. The number and arrangement positions of the first connecting members 21e and the first connecting members 21f are also not particularly limited. The first connecting member 21e or the first connecting member 21f may not be arranged in any of the spaces 21c. Instead of both the first connecting member 21e and the first connecting member 21f being arranged in the first side walls 21B to 21D, only the first connecting member 21e or only the first connecting member 21f may be arranged. In addition to the first side walls 21B to 21D or instead of the first side walls 21B to 21D, the first connecting member 21e and the first connecting member 21f may be arranged in a wall (the second side wall 22, the bottom wall 23, or the upper wall 24) other than the first side walls 21B to 21D.

[0082] (Variation 4) In the above embodiment, the energy storage device 1 includes the case 20 that houses the energy storage unit 10, and the case 20 includes the first side wall 21 and the second side wall 22, but is not limited to this. Fig. 11 is a perspective view showing the appearance of the energy storage device 2 according to the fourth modification of the present embodiment. Fig. 11 is a view corresponding to Fig. 1.

[0083] As shown in FIG. 11, unlike the energy storage device 1 in the above embodiment, the energy storage device 2 in this modification does not include the case 20, and includes a case 101 instead of the case 100 in the above embodiment. The case 101 includes a case body 130 instead of the case body 110 in the above embodiment. The case body 130 includes a pair of first side walls 31 arranged on both sides in the X-axis direction, a pair of second side walls 32 arranged on both sides in the Y-axis direction, and a bottom wall 33 arranged in the negative Z-axis direction. The pair of first side walls 31, the pair of second side walls 32, and the bottom wall 33 correspond to the pair of short side walls 111, the pair of long side walls 112, and the bottom wall 113 in the above embodiment, but have the same configuration as the pair of first side walls 21, the pair of second side walls 22, and the bottom wall 23 in the above embodiment. The other configurations of this modification are the same as those of the above embodiment, so detailed description will be omitted.

[0084] Thus, in this modification, the case 101 that houses the energy storage element 200 includes a first side wall 31 facing the X-axis direction (first direction), a second side wall 32 facing the Y-axis direction (second direction), and a bottom wall 33 facing the Z-axis direction (third direction). The first side wall 31, like the first side wall 21, includes a pair of first plate-shaped members facing each other in the X-axis direction (first direction) and a first connecting member that connects the pair of first plate-shaped members and extends in a direction perpendicular to the X-axis direction (first direction). The second side wall 32, like the second side wall 22, includes a pair of second plate-shaped members facing each other in the Y-axis direction (second direction) and a second connecting member that connects the pair of second plate-shaped members and extends in a direction perpendicular to the Y-axis direction (second direction). Similar to bottom wall 23, bottom wall 33 includes a pair of third plate-like members facing each other in the Z-axis direction (third direction), and a third connecting member connecting the pair of third plate-like members and extending in a direction perpendicular to the Z-axis direction (third direction). At least one of the first connecting member and the second connecting member extends in a direction different from the X-axis direction (first direction) and the Y-axis direction (second direction). The second connecting member extends in a direction different from the extending direction of the first connecting member. The third connecting member extends in a direction different from the extending direction of the first connecting member and the extending direction of the second connecting member.

[0085] As described above, according to this modification, the same effects as those of the above embodiment are achieved. In particular, in this modification, the energy storage device 2 does not include the case 20 in the above embodiment, and the strength can be improved by the case 101. This allows the strength of the energy storage device 2 to be improved with a simple configuration.

[0086] The above-mentioned modifications 1 to 3 can also be applied to this modification. That is, the first side wall 31 may include a filler disposed in a space formed between the pair of first plate-like members. The case 101 may include a connection member that connects the first side wall 31 to a wall other than the first side wall 31 (the second side wall 32, the bottom wall 33), and the connection member may be disposed in a space formed between the pair of first plate-like members of the first side wall 31. The first connecting member of the first side wall 31 may be disposed inclined with respect to the X-axis direction (first direction). The same applies to the second side wall 32 and the bottom wall 33.

[0087] (Other variations) In the above embodiment, the case 20 accommodates only one power storage unit 10, but it may accommodate a plurality of power storage units 10.

[0088] In the above embodiment, in the case 20, the pair of first side walls 21 are arranged on both sides of the pair of second side walls 22 in the X-axis direction, and the bottom wall 23 and the top wall 24 are arranged on both sides of the pair of first side walls 21 and the pair of second side walls 22 in the Z-axis direction, but the positional relationship of these walls is not particularly limited. The pair of second side walls 22 may be arranged on both sides of the pair of first side walls 21 in the Y-axis direction. For one second side wall 22, one first side wall 21 may be arranged on the X-axis direction of the second side wall 22, and the other first side wall 21 may be arranged on the Y-axis direction of the second side wall 22. The same applies to the other walls.

[0089] In the above embodiment, the case 20 has six walls, namely, a pair of first side walls 21, a pair of second side walls 22, a bottom wall 23, and an upper wall 24. However, the case 20 is not limited to having all of the six walls. The case 20 only needs to have one first side wall 21 and one second side wall 22. In other words, the case 20 does not need to have any one of the six walls. The case 20 does not need to have two opposing walls (the bottom wall 23 and the upper wall 24) of the six walls. The case 20 does not need to have two adjacent walls (one first side wall 21 and the bottom wall 23, one first side wall 21 and the upper wall 24, one second side wall 22 and the bottom wall 23, one second side wall 22 and the upper wall 24, or one first side wall 21 and one second side wall 22). The case 20 may not have three walls (the one first side wall 21, the bottom wall 23, the top wall 24, etc.) among the six walls. The case 20 may not have four walls other than the one first side wall 21 and the one second side wall 22 among the six walls.

[0090] In the above embodiment, the pair of first side walls 21 have the same configuration, but the pair of first side walls 21 may have different configurations, such as the first connecting members 21b extending in different directions. The same applies to the pair of second side walls 22. The same applies to the bottom wall 23 and the top wall 24.

[0091] In the above embodiment, the first connecting member 21b of the first side wall 21 extends in the Z-axis direction, but may extend in a direction inclined from the Z-axis direction. The second connecting member 22b of the second side wall 22 extends in the X-axis direction, but may extend in a direction inclined from the X-axis direction. The third connecting member 23b of the bottom wall 23 extends in the Y-axis direction, but may extend in a direction inclined from the Y-axis direction. The third connecting member 24b of the upper wall 24 extends in the Y-axis direction, but may extend in a direction inclined from the Y-axis direction.

[0092] In the above embodiment, the second connecting member 22b extends in a direction different from the extension direction of the first connecting member 21b, but it may extend in the same direction as the extension direction of the first connecting member 21b. The third connecting member 23b extends in a direction different from the extension direction of the first connecting member 21b and the extension direction of the second connecting member 22b, but it may extend in the same direction as the extension direction of the first connecting member 21b or the extension direction of the second connecting member 22b. The same applies to the third connecting member 24b.

[0093] In the above embodiment, the first connecting member 21b extends in a direction different from the X-axis direction (first direction) and the Y-axis direction (second direction), but the second connecting member 22b may extend in a direction different from the X-axis direction (first direction) and the Y-axis direction (second direction). Alternatively, both the first connecting member 21b and the second connecting member 22b may extend in a direction different from the X-axis direction (first direction) and the Y-axis direction (second direction). In other words, it is sufficient that at least one of the first connecting member 21b and the second connecting member 22b extends in a direction different from the X-axis direction (first direction) and the Y-axis direction (second direction).

[0094] In the above embodiment, the space 21c formed in the first side wall 21 may be used as a gas exhaust path when the gas from the energy storage element 200 is exhausted from inside the case 20 to the outside, or as a passage (cooling passage) for a coolant (air or water, etc.) when cooling the energy storage device 1. That is, the case 20 is configured to allow ventilation between the inside and outside of the case 20 through the space 21c, and a membrane member such as a breathable waterproof membrane is arranged to cover the space 21c, so that the space 21c can be used as a gas exhaust path. The case 20 is configured to allow the coolant to pass through the space 21c, so that the space 21c can be used as a cooling passage. The same is true for the space 22c of the second side wall 22, the space 23c of the bottom wall 23, and the space 24c of the upper wall 24. In particular, the space 23c and the space 24c are not blocked by other walls (the pair of first side walls 21 and the pair of second side walls 22) and are open to the outside of the case 20, so that they can be easily used as a gas exhaust path, a cooling passage, etc. When the case 20 is an aluminum extrusion, corrosion or deformation of the case 20 due to gas is suppressed, so that the function as a gas discharge path is maintained for a long period of time. When the case 20 is an aluminum extrusion, heat generated in the case 20 can be smoothly transferred from the case 20 to the refrigerant, so that the performance of the electricity storage device 1 can be maintained for a long period of time.

[0095] In the above embodiment, the energy storage device 1 accommodates the energy storage unit 10 inside the case 20, but the energy storage device 2 may be accommodated instead of the energy storage unit 10. In other words, the strength of the energy storage device 1 can be improved by both the case 20 constituting the energy storage device 1 and the case 101 constituting the energy storage device 2.

[0096] Any combination of the components included in the above-described embodiment and its modified examples is also included within the scope of the present invention. [Industrial Applicability]

[0097] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0098] 1, 2 Energy storage device 10 Energy storage unit 20, 20A case 21, 21A, 21B, 21C, 21D, 31 First side wall 21a First plate-shaped member 21b, 21e, 21f First connecting member 21c, 22c, 23c, 24c space 21d Filling material 22, 32 Second side wall 22a Second plate-shaped member 22b Second connecting member 23, 33 Bottom wall 23a, 24a Third plate-shaped member 23b, 24b Third connecting member 24 Upper Wall 25 Connection parts 100, 101 cases 110, 130 Case body 111 Short side wall 112 Long side wall 113 Bottom wall 120 Case cover 121 Positive terminal 122 negative terminal 200 Energy storage element 210 Container 211 Container body 212 Container lid 213 Gas exhaust valve 220 Terminal 300, 310, 320, 330 Busbars

Claims

1. A storage element; A case that houses the power storage element, The case is a first side wall facing a first direction; a second side wall facing a second direction intersecting the first direction, The first side wall is A pair of first plate-like members facing each other in the first direction; a first connecting member that connects the pair of first plate-like members and extends in a direction perpendicular to the first direction, The second side wall is A pair of second plate-like members facing each other in the second direction; A second connecting member that connects the pair of second plate-like members and extends in a direction perpendicular to the second direction, At least one of the first connecting member and the second connecting member extends in a direction different from the first direction and the second direction. Energy storage device.

2. The second connecting member extends in a direction different from the direction in which the first connecting member extends. The power storage device according to claim 1 .

3. The case further includes at least one of a bottom wall and an upper wall that faces a third direction intersecting the first direction and the second direction, At least one of the bottom wall and the top wall is A pair of third plate-like members facing each other in the third direction; a third connecting member connecting the pair of third plate-like members and extending in a direction perpendicular to the third direction, The third connecting member extends in a direction different from the extending direction of the first connecting member and the extending direction of the second connecting member. The power storage device according to claim 2 .

4. The first connecting member is disposed inclined with respect to the first direction. The power storage device according to any one of claims 1 to 3.

5. the case further includes a connection member that connects the first side wall and a wall other than the first side wall, The connection member is disposed in a space formed between the pair of first plate-like members. The power storage device according to any one of claims 1 to 3.

6. The first side wall further includes a filler disposed in a space formed between the pair of first plate-like members. The power storage device according to any one of claims 1 to 3.

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