Power storage device

Abstract

A power storage apparatus (1) comprises a power storage element (200) and an outer case (100) in which the power storage element (200) is housed, the outer case (100) including a first outer case (110) and a second outer case (120) aligned in a first direction and joined to each other with the power storage element (200) sandwiched and constrained therebetween in the first direction. The first outer case (110) and the second outer case (120) respectively include: a first connecting portion (111) and a second connecting portion (121) which are disposed at the outer periphery of the first outer case (110) and the second outer case (120) when viewed from the first direction, and which are joined in a state of abutting on each other; and a third connecting portion (112) and a fourth connecting portion (122) which are disposed on the inside of the outer periphery when viewed from the first direction, and which are joined to each other. The third connecting portion (112) and the fourth connecting portion (122) are joined in a mutually spaced-apart state by means of a joint member (140).

Description

[Technical Field]

[0001] The present invention relates to an energy storage device including an energy storage element and an exterior body. [Background technology]

[0002] Conventionally, there has been known a power storage device that includes a power storage element and an exterior body that houses the power storage element, with the power storage element being constrained within the exterior body. For example, Patent Document 1 discloses a power supply device (power storage device) in which a plurality of battery cells (power storage elements) are sandwiched between two end plates and housed in an upper case and a lower case (exterior body). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 131837 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional energy storage devices described above, the number of parts is large, which raises concerns about increased weight, increased costs, reduced productivity, etc. The energy storage device disclosed in Patent Document 1 described above has a configuration in which multiple energy storage elements are sandwiched and restrained between two end plates to prevent swelling or movement of the energy storage elements within the exterior body (upper case and lower case), which increases the number of parts. In an energy storage device, an increase in the number of parts can cause problems such as increased weight, increased size, increased costs, and reduced productivity.

[0005] The present invention was made by the present inventors by focusing on the above-mentioned problem, and has an object to provide a power storage device that can reduce the number of parts. [Means for solving the problem]

[0006] A storage device according to one embodiment of the present invention is a storage device comprising an energy storage element and an outer casing in which the energy storage element is housed, wherein the outer casing has a first outer casing and a second outer casing that are arranged side by side in a first direction and are joined to each other to sandwich and restrain the energy storage element in the first direction, and the first outer casing and the second outer casing have a first connecting portion and a second connecting portion that are arranged on the outer peripheries of the first outer casing and the second outer casing when viewed from the first direction and are joined in an abutting state, and a third connecting portion and a fourth connecting portion that are arranged inside the outer periphery when viewed from the first direction and are joined to each other, and the third connecting portion and the fourth connecting portion are joined by a joining member while spaced apart from each other. [Effects of the Invention]

[0007] According to the electricity storage device of the present invention, the number of parts can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing components included in the electricity storage device according to the embodiment. [Figure 3] FIG. 3 is an exploded perspective view showing components included in the electricity storage device according to the embodiment. [Figure 4] FIG. 4 is an exploded perspective view showing the components of the energy storage device according to the embodiment. [Figure 5] FIG. 5 is a perspective view showing the configuration of an exterior body (first exterior body and second exterior body) according to the embodiment. [Figure 6] FIG. 6 is a perspective view showing the configuration of the spacer (first spacer and second spacer) according to the embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing the positional relationship between the exterior body (first exterior body and second exterior body) and the spacer (first spacer and second spacer) according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A storage device according to one embodiment of the present invention is a storage device comprising an energy storage element and an outer casing in which the energy storage element is housed, wherein the outer casing has a first outer casing and a second outer casing that are arranged side by side in a first direction and are joined to each other to sandwich and restrain the energy storage element in the first direction, and the first outer casing and the second outer casing have a first connecting portion and a second connecting portion that are arranged on the outer peripheries of the first outer casing and the second outer casing when viewed from the first direction and are joined in an abutting state, and a third connecting portion and a fourth connecting portion that are arranged inside the outer periphery when viewed from the first direction and are joined to each other, and the third connecting portion and the fourth connecting portion are joined by a joining member while spaced apart from each other.

[0010] According to this, in the energy storage device, the exterior housing that houses the energy storage element has a first exterior housing and a second exterior housing that sandwich and restrain the energy storage element. The first exterior housing and the second exterior housing have a first connection portion and a second connection portion that are joined in an abutting state at the outer periphery, and a third connection portion and a fourth connection portion that are joined by a joining member in a spaced-apart state on the inside of the outer periphery. In this way, by restraining the energy storage element with the exterior housing (the first exterior housing and the second exterior housing), the energy storage element can be restrained without disposing an end plate. Furthermore, when restraining the energy storage element with the exterior housing, there is a risk that the energy storage element may not be firmly restrained. Therefore, the first exterior housing and the second exterior housing are joined not only at the abutting position (the outer periphery) but also at a spaced-apart position (inside the outer periphery). This allows the exterior housing (the first exterior housing and the second exterior housing) to firmly sandwich and restrain the energy storage element. Therefore, the energy storage device can be firmly sandwiched and restrained by the exterior bodies (first exterior body and second exterior body) without the need for end plates, thereby reducing the number of parts.

[0011] The spacer may be arranged alongside the energy storage element in the first direction, a portion of the spacer being arranged between the third connection portion and the fourth connection portion, and a through hole being formed in that portion, and the joining member may join the third connection portion and the fourth connection portion while passing through the through hole.

[0012] According to this, a portion of the spacer is disposed between the third connection portion and the fourth connection portion, and in order to join the third connection portion and the fourth connection portion, a through hole is formed in the portion, and a joining member is passed through the through hole to join the third connection portion and the fourth connection portion. This allows the first exterior body and the second exterior body to be firmly joined even when a portion of the spacer is disposed between the third connection portion and the fourth connection portion. Therefore, even without disposing an end plate, the energy storage element can be firmly sandwiched and restrained by the exterior bodies (first exterior body and second exterior body), thereby reducing the number of parts.

[0013] The third connection portion and the fourth connection portion may be disposed in a central portion of the first exterior body and the second exterior body when viewed from the first direction.

[0014] According to this, the third connecting portion and the fourth connecting portion are disposed in the central portions of the first and second exterior bodies, and therefore the first and second exterior bodies are joined at their central portions. This allows the first and second exterior bodies to be firmly joined. Therefore, even without disposing end plates, the exterior bodies (first and second exterior bodies) can firmly sandwich and restrain the energy storage element, thereby reducing the number of parts.

[0015] In at least one of the third connection portion and the fourth connection portion, a joining member that joins the third connection portion and the fourth connection portion may be disposed at a position that is not exposed to the outside.

[0016] According to this, at least one of the third connection portion and the fourth connection portion, the joining member is not exposed to the outside, which improves the airtightness of the exterior body and saves space.

[0017] The storage element may have an electrode body in which electrode plates are stacked in the first direction, and a plurality of the storage elements may be arranged in a second direction intersecting the first direction, and the first outer casing and the second outer casing may sandwich and restrain the plurality of storage elements in the first direction.

[0018] According to this, the first and second exterior bodies sandwich and restrain a plurality of energy storage elements arranged in a direction intersecting the stacking direction of the electrode plates in the stacking direction of the electrode plates. In this way, even when a plurality of energy storage elements are arranged in a direction intersecting the stacking direction of the electrode plates, the first and second exterior bodies can collectively restrain the plurality of energy storage elements. This reduces the number of parts compared to restraining the plurality of energy storage elements individually.

[0019] The present invention can be realized not only as an electricity storage device, but also as an exterior body (first exterior body and second exterior body), or as a combination of an exterior body and a spacer.

[0020] Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including its modified examples). Note that the embodiments described below all show comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples only and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each drawing, the same or similar components are designated by the same reference numerals.

[0021] In the following description and drawings, the longitudinal direction of the energy storage device, the arrangement direction of the energy storage unit and the control unit, the opposing direction of the short side surfaces of the container of the energy storage element, or the arrangement direction of a pair of electrode terminals of the energy storage element is defined as the X-axis direction. The transverse direction of the energy storage device, the arrangement direction of the energy storage element, the bus bar plate, the bus bar, and the bus bar cover, the arrangement direction of the main body and the lid of the container of the energy storage element, or the protruding direction of the electrode terminals of the energy storage element is defined as the Y-axis direction. The arrangement direction of the main body and the lid of the exterior body of the energy storage device, the arrangement direction of the energy storage element and the spacer, the opposing direction of the long side surfaces of the container of the energy storage element, the stacking direction of the electrode plates of the electrode body of the energy storage element, or the up-down direction is defined as the Z-axis direction. The X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that depending on the usage mode, the Z-axis may not be the up-down direction; however, for convenience of explanation, the Z-axis will be described below as the up-down direction.

[0022] 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 direction opposite to the positive X-axis direction. The same applies to the Y-axis and Z-axis directions. Hereinafter, the Z-axis direction may also be referred to as the first direction, the X-axis direction as the second direction, and the Y-axis direction as the third direction. Expressions indicating relative directions or attitudes, such as parallel and perpendicular, may also include cases where the directions or attitudes are not strictly those of the same kind. "Two directions being parallel" does not only mean that the two directions are completely parallel, but also means that the directions are substantially parallel, i.e., there is a difference of a few percent. Furthermore, in the following description, "insulation" means "electrical insulation."

[0023] (Embodiment) [1 General Description of the Energy Storage Device 1] A schematic configuration of an energy storage device 1 according to the present embodiment will be described. Fig. 1 is a perspective view showing the appearance of the energy storage device 1 according to the present embodiment. Figs. 2 and 3 are exploded perspective views showing components of the energy storage device 1 according to the present embodiment in an exploded form. Fig. 3 shows a further exploded configuration of the exterior body 100, energy storage elements 200, and spacers 300 shown in Fig. 2.

[0024] The power storage device 1 is a device that can charge with electricity from an external source and discharge electricity to the outside, and in this embodiment, has a substantially rectangular parallelepiped shape. The power storage device 1 is a battery module (battery assembly) used for power storage, power supply, or the like. Specifically, the power storage device 1 is used as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train 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.

[0025] 1 and 2, the energy storage device 1 includes an energy storage unit 10 and a control unit 20, and the energy storage unit 10 includes an exterior body 100 and a terminal unit 30. In other words, hereinafter, a portion of the energy storage device 1 including the energy storage elements 200 will be referred to as the energy storage unit 10, and a portion including a control device for controlling the energy storage elements 200 will be referred to as the control unit 20. As shown in FIGS. 2 and 3, the exterior body 100 accommodates the energy storage elements 200, spacers 300 (first spacer 310 and second spacer 320), a bus bar plate 400, bus bars 500 (510 to 530), a bus bar cover 600, and the control unit 20. In addition to the above components, the energy storage device 1 may also include an exhaust unit for exhausting gas discharged from the energy storage elements 200 to the outside of the exterior body 100.

[0026] The terminal unit 30 is a member having external terminals 31a, which are module terminals (general terminals) on the positive or negative side of the energy storage device 1, and is attached to the end of the side wall (long side wall 120b described below) of the exterior housing 100 in the negative Y-axis direction, in the negative X-axis direction. The terminal unit 30 has a bus bar 31. The bus bar 31 is a plate-shaped conductive member, and is formed of, for example, a conductive member made of metal such as aluminum, aluminum alloy, copper, copper alloy, or nickel, or a combination thereof, or a conductive member other than metal. The end of the bus bar 31 in the positive Y-axis direction is connected to the bus bar 520, and the end of the bus bar 31 in the negative Y-axis direction functions as the external terminal 31a. The external terminal 31a is, for example, a negative external terminal. As a result, the energy storage elements 200 of the energy storage unit 10 and the external terminal 31a are electrically connected via the bus bar 520. Bus bar 31 and bus bar 520 are connected (joined) by bolting, but may also be connected (joined) by welding or the like.

[0027] The control unit 20 is a device having a control device (not shown) that controls the energy storage elements 200 of the energy storage unit 10, and specifically, is a BMS (Battery Management System) that controls the energy storage elements 200. The control device is, for example, a circuit board that controls charging and discharging of the energy storage elements 200, a fuse, a relay, a semiconductor switch such as a FET (Field Effect Transistor), a shunt resistor, etc.

[0028] An external terminal 21, which is a module terminal (general terminal) on the positive or negative side of the energy storage device 1, is arranged on the exterior body 100 at an end in the positive direction of the X axis and the negative direction of the Y axis. The external terminal 21 is a terminal of a different polarity (for example, a positive external terminal) from the external terminal 31a of the terminal unit 30. The external terminal 21 is electrically connected to the energy storage element 200. The energy storage device 1 charges with electricity from the outside and discharges electricity to the outside via these external terminals 21 and 31a. The external terminal 21 is formed, for example, from any conductive material that can be used for the bus bar 31.

[0029] The exterior body 100 is a box-shaped (approximately rectangular parallelepiped) container (module case) that forms the housing (outer shell) of the energy storage device 1 (energy storage unit 10). The exterior body 100 is arranged outside the energy storage elements 200, etc., and secures these energy storage elements 200, etc. in predetermined positions to protect them from impacts and the like. The exterior body 100 has a first exterior body 110 and a second exterior body 120 that are arranged side by side in the Z-axis direction (first direction), and joining members 130 and 140 and a collar 150 for joining the first exterior body 110 and the second exterior body 120.

[0030] The first exterior housing 110 is disposed in the negative Z-axis direction of the second exterior housing 120 and is a flat, rectangular member that constitutes the bottom wall of the exterior housing 100, on which the energy storage device 200 and the like are placed. The second exterior housing 120 is a bottomed, rectangular, tubular member that constitutes the main body (portion other than the bottom wall) of the exterior housing 100 and is connected (joined) to the first exterior housing 110 to cover the energy storage device 200 and the like. The second exterior housing 120 has an upper wall 120a, a pair of long side walls 120b, and a pair of short side walls 120c. In other words, an opening facing the negative Z-axis direction is formed in the second exterior housing 120, and the first exterior housing 110 functions as a lid that covers the opening in the second exterior housing 120. From the viewpoint of ensuring safety (crush resistance), the first exterior body 110 and the second exterior body 120 are formed from highly rigid materials such as metal members such as stainless steel, aluminum, aluminum alloy, iron, and steel plate, or such metal members that have been subjected to an insulating treatment such as an insulating coating. The first exterior body 110 and the second exterior body 120 can be formed from aluminum die-casting or the like. The first exterior body 110 and the second exterior body 120 may be formed from materials of the same material or from materials of different materials.

[0031] Specifically, connecting portions 111 and 112 of first exterior housing 110 and connecting portions 121 and the like of second exterior housing 120 are joined using joining members 130, 140 and a collar 150, thereby connecting (fixing) first exterior housing 110 and second exterior housing 120. Long side wall 120b, which is a wall portion (side wall) in the negative Y-axis direction of second exterior housing 120, is positioned so as to sandwich bus bar plate 400, bus bars 500 (510 to 530), and bus bar cover 600 between second exterior housing 120 and energy storage element 200. A through hole 125 is formed in long side wall 120b. Through hole 125 is a rectangular through hole as viewed from the Y-axis direction, which is positioned at the end of long side wall 120b in the negative X-axis direction and penetrates long side wall 120b in the Y-axis direction. Through hole 125 is a through hole through which bus bar 31 passes when bus bar 31 of terminal unit 30 is connected (joined) to bus bar 520.

[0032] In the present embodiment, the first exterior housing 110 and the second exterior housing 120 are joined to each other and sandwich the energy storage element 200. That is, the first exterior housing 110 and the second exterior housing 120 sandwich and restrain the energy storage element 200 in the Z-axis direction (first direction), thereby applying a restraining force to the energy storage element 200 in the Z-axis direction. Specifically, the first exterior housing 110 and the second exterior housing 120 are disposed across the multiple energy storage elements 200 aligned in the X-axis direction at positions sandwiching the multiple energy storage elements 200 aligned in the X-axis direction and the Z-axis direction and the multiple spacers 300 (first spacers 310 and second spacers 320) aligned in the Z-axis direction in the Z-axis direction (first direction). The first exterior housing 110 and the second exterior housing 120 sandwich and restrain the multiple energy storage elements 200 and the multiple spacers 300 collectively. In this manner, the first exterior housing 110 and the second exterior housing 120 can also be said to be a pair of end plates. The configuration of exterior housing 100 (first exterior housing 110 and second exterior housing 120) will be described in detail below.

[0033] The energy storage elements 200 are secondary batteries (single cells) that can charge and discharge electricity, and more specifically, nonaqueous electrolyte secondary batteries such as lithium-ion secondary batteries. The energy storage elements 200 have a flattened rectangular parallelepiped (rectangular) shape, with a plurality of energy storage elements 200 arranged in the X-axis direction (a second direction intersecting the first direction) and stacked in the Z-axis direction (a first direction). In this embodiment, eight energy storage elements 200 are arranged in the X-axis and Z-axis directions in a horizontally placed (laid-down) state (with a long side surface 211a, described later, of each energy storage element 200 facing the Z-axis direction). Specifically, four energy storage elements 201 to 204 are arranged side by side in the X-axis direction from the negative direction to the positive direction of the X-axis, and four energy storage elements 205 to 208 are arranged side by side in the X-axis direction from the negative direction to the positive direction of the X-axis. Four energy storage elements 201 to 204 and four energy storage elements 205 to 208 are stacked (flatly stacked) in the Z-axis direction.

[0034] The number of the energy storage elements 200 is not particularly limited, and any number of the energy storage elements 200 may be arranged (arranged) in the X-axis direction, or any number of the energy storage elements 200 may be arranged (stacked) in the Z-axis direction. The shape of the energy storage element 200 is not limited to the above-mentioned rectangular shape, and may be other shapes such as a polygonal prism, a cylindrical shape, an elliptical cylindrical shape, or an oblong cylindrical shape. 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 not be a secondary battery, but may be a primary battery that can use stored electricity without the user having to charge it. 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. A detailed description of the configuration of the energy storage element 200 will be given later.

[0035] The spacer 300 is a rectangular, flat spacer that is aligned with the energy storage element 200 in the Z-axis direction (first direction) and is disposed adjacent to the energy storage element 200. The spacer 300 is disposed opposite the long side surface 211a of the energy storage element 200 in the positive Z-axis direction or the negative Z-axis direction of the energy storage element 200. The spacer 300 is formed from a resin material (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), polyethersulfone (PES), polyamide (PA), ABS resin, or a composite material thereof, or a heat insulating material such as a damper material.

[0036] In this embodiment, a first spacer 310 and a pair of second spacers 320 are arranged as the spacers 300. The first spacer 310 is arranged adjacent to the plurality of energy storage elements 200 arranged in the X-axis direction in the Z-axis direction (first direction) and extends across the plurality of energy storage elements 200. Specifically, the first spacer 310 is arranged adjacent to four energy storage elements 200 (201 to 204 or 205 to 208) arranged in the X-axis direction in the Z-axis direction and extends across the four energy storage elements 200. In this embodiment, the first spacer 310 is an intermediate spacer arranged between the energy storage elements 200 adjacent to each other in the Z-axis direction (between the four energy storage elements 201 to 204 and the four energy storage elements 205 to 208).

[0037] The second spacers 320 are arranged across the plurality of energy storage elements 200 arranged in the X-axis direction at positions where the plurality of energy storage elements 200 are sandwiched in the Z-axis direction (first direction) between the second spacers 320 and the first spacers 310. Specifically, the second spacers 320 are arranged across the four energy storage elements 200 (201 to 204 or 205 to 208) arranged in the X-axis direction at positions where the four energy storage elements 200 are sandwiched in the Z-axis direction between the second spacers 320 and the first spacers 310. In this embodiment, the second spacers 320 are end spacers arranged between the energy storage elements 200 and the first exterior housing 110 or the second exterior housing 120. Specifically, a pair of second spacers 320 are arranged between the four energy storage elements 205 to 208 and the first exterior housing 110, and between the four energy storage elements 201 to 204 and the second exterior housing 120.

[0038] In this way, the first spacer 310 and the pair of second spacers 320 are arranged to sandwich the energy storage element 200 in the Z-axis direction, providing insulation between the energy storage elements 200 and between the energy storage element 200 and the first exterior housing 110 and the second exterior housing 120. A detailed description of the configuration of the spacers 300 (first spacer 310 and second spacer 320) will be given later.

[0039] The bus bar plate 400 is a flat, rectangular insulating member that is disposed between the energy storage elements 200 and the bus bar 500, and that can insulate the bus bar 500 from other members and regulate the position of the bus bar 500. The bus bar plate 400 is formed, for example, from any insulating resin material that can be used for the spacer 300. The bus bar plate 400 is disposed in the negative Y-axis direction of the multiple energy storage elements 200, and is positioned relative to the multiple energy storage elements 200. In this way, the bus bar 500 is positioned relative to the multiple energy storage elements 200, and is joined to electrode terminals 220 (described later) that the multiple energy storage elements 200 have.

[0040] The busbar 500 is a plate-shaped member that is arranged in the negative Y-axis direction of the multiple energy storage elements 200 and is connected (joined) to the multiple energy storage elements 200 and the terminal unit 30. In the present embodiment, three busbars 500 are arranged: a busbar 510, a busbar 520, and a busbar 530. The busbar 510 is arranged between the busbars 520 and 530 and connects the electrode terminals 220 of adjacent energy storage elements 200 to each other. The busbar 520 is arranged furthest in the negative X-axis direction among the multiple busbars 500 and connects the electrode terminal 220 of the energy storage element 200 that is furthest in the negative X-axis direction to the busbar 31 of the terminal unit 30, thereby electrically connecting the energy storage element 200 to the external terminal 31 a. Bus bar 530 is arranged furthest in the positive X-axis direction among multiple bus bars 500, and electrically connects external terminal 21 to electrode terminal 220 of energy storage element 200 that is furthest in the positive X-axis direction.

[0041] In the present embodiment, bus bar 500 and electrode terminals 220 of energy storage elements 200 are connected (joined) by welding, but may also be connected (joined) by bolting or the like. Bus bar 500 is formed, for example, from any conductive material that can be used for bus bar 31. In the present embodiment, bus bar 500 connects energy storage elements 200 in parallel in pairs to form four sets of energy storage element groups, and these four sets of energy storage element groups are connected in series; however, the connection form of bus bar 500 is not particularly limited.

[0042] The busbar cover 600 is an insulating cover member disposed to cover the busbar 500 and insulate the busbar 500 from other components. In this embodiment, the busbar cover 600 is a plate-shaped member extending in the X-axis direction across the multiple busbars 500 (510 to 530) so as to cover the multiple busbars 500. The busbar cover 600 is disposed between the busbar 500 and a wall portion (long side wall 120b in the negative Y-axis direction) of the second exterior body 120. This insulates the multiple busbars 500 from other components such as the long side wall 120b. The busbar cover 600 is formed, for example, from any insulating resin material that can be used for the spacer 300. The busbar cover 600 is disposed at a position where the busbar 500 is sandwiched between the busbar cover 600 and the busbar plate 400, and is attached and fixed to the busbar plate 400 by, for example, having a portion that fits with the busbar plate 400.

[0043] [2. Description of the Energy Storage Element 200] The configuration of the energy storage element 200 will be described in detail. Since all eight energy storage elements 200 (201 to 208) included in the energy storage unit 10 have the same configuration, the configuration of one energy storage element 200 will be described below. Fig. 4 is an exploded perspective view showing the components of the energy storage element 200 according to this embodiment. Specifically, Fig. 4 shows the energy storage element 200 shown in Fig. 3 in a vertically placed (standing) state, with each part disassembled.

[0044] As shown in FIG. 4, the energy storage element 200 includes a container 210, a pair of electrode terminals 220 (positive and negative), and a pair of gaskets 230 (positive and negative). The container 210 contains a pair of gaskets 240 (positive and negative), a pair of current collectors 250 (positive and negative), and an electrode assembly 260. An electrolyte (non-aqueous electrolyte) is enclosed within the container 210, but this is not shown. The type of electrolyte is not particularly limited 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 components, spacers disposed on the sides or below the electrode assembly 260, an insulating film enclosing the electrode assembly 260, or an insulating sheet covering the outer surface of the container 210 may also be disposed.

[0045] The container 210 is a rectangular parallelepiped (square or box-shaped) case having 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 210 is structured so that the interior can be sealed by accommodating the electrode assembly 260 and the like inside the container body 211 and then joining the container body 211 and the container lid 212 by welding or the like. The materials of the container body 211 and the container lid 212 are not particularly limited, but are preferably weldable metals such as stainless steel, aluminum, aluminum alloy, iron, and plated steel sheet.

[0046] The container body 211 is a rectangular cylindrical member having a bottom and constituting the main body of the container 210, and has an opening formed on the negative Y-axis side. That is, the container body 211 has a pair of rectangular, planar (flat) long side surfaces 211a on both sides in the Z-axis direction, a pair of rectangular, planar (flat) short side surfaces 211b on both sides in the X-axis direction, and a rectangular, planar (flat) bottom surface 211c on the positive Y-axis side. The container lid 212 is a rectangular plate-like member constituting the lid of the container 210, and is disposed so as to extend in the X-axis direction in the negative Y-axis direction of the container body 211. The container lid 212 is provided with a gas exhaust valve 212a that releases pressure inside the container 210 when the pressure inside the container 210 increases, a liquid injection part (not shown) for injecting electrolyte into the container 210, and the like.

[0047] The electrode body 260 is an electricity storage element (power generation element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is formed by forming a positive electrode active material layer on a positive electrode substrate layer, which is a current collecting foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is formed by forming a negative electrode active material layer on a negative electrode substrate layer, which is a current collecting foil made of a metal such as copper or a copper alloy. 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 is capable of absorbing and releasing lithium ions. In this embodiment, the electrode body 260 is a wound type (so-called vertically wound type) electrode body formed by winding the electrode plates (positive electrode plate and negative electrode plate) around a winding axis (a virtual axis parallel to the X-axis direction) extending in the X-axis direction.

[0048] The electrode plates (positive and negative electrode plates) of the electrode assembly 260 are stacked in the Z-axis direction (first direction), and the Z-axis direction (first direction) is also referred to as the stacking direction. That is, the electrode assembly 260 is formed by stacking the electrode plates in the stacking direction. The electrode assembly 260 has a pair of flat portions 261 aligned in the Z-axis direction and a pair of curved portions 262 aligned in the Y-axis direction by winding the electrode plates. The stacking direction is the stacking direction of the electrode plates in the flat portions 261. The flat portions 261 are flat portions connecting the ends of the pair of curved portions 262, and the curved portions 262 are curved portions, such as semicircular, that protrude in the Y-axis direction. The stacking direction can be defined as the direction in which the flat surface of the flat portions 261 faces or the direction in which the pair of flat portions 261 face each other. Therefore, it can be said that the energy storage elements 201 and 205 are aligned in the stacking direction. The same applies to the other energy storage elements 200. The X-axis direction in which energy storage elements 201 to 204 are arranged is also referred to as the arrangement direction. That is, energy storage elements 201 to 204 are arranged in an arrangement direction that intersects with the stacking direction. The same applies to energy storage elements 205 to 208.

[0049] In the electrode body 260, the positive and negative electrode plates are wound with a mutual offset in the X-axis direction, and therefore the positive and negative electrode plates have portions (active material layer non-formed portions) at the ends in the offset direction where the active material is not formed (coated) and the base material layer is exposed. In other words, the electrode body 260 has ends 263 at both ends in the X-axis direction that protrude on both sides in the X-axis direction from the flat portion 261 and the curved portion 262, and are connected to the current collector 250 by stacking the active material layer non-formed portions of the positive and negative electrode plates.

[0050] The electrode body 260 may be of any type, such as a so-called horizontally wound electrode body formed by winding electrode plates around a winding axis extending in the Y-axis direction, a laminated (stacked) electrode body formed by stacking multiple flat electrode plates, or a bellows-shaped electrode body in which electrode plates are folded like bellows. In the case of a horizontally wound electrode body, the flat portion is the flat part other than the curved part and the connection part (tab) with the current collector, and in the case of a laminated (stacked) and bellows-shaped electrode body, the flat part is the flat part other than the connection part (tab) with the current collector.

[0051] The electrode terminals 220 are terminal members (positive and negative electrode terminals) of the energy storage element 200, and are arranged on the container lid 212 so as to protrude in the negative Y-axis direction. The electrode terminals 220 are electrically connected to the positive and negative electrode plates of the electrode body 260 via the current collectors 250. The electrode terminals 220 are formed of a conductive material such as a metal, such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0052] The current collectors 250 are conductive members (positive electrode current collector and negative electrode current collector) electrically connected to the electrode terminal 220 and the end 263 of the electrode body 260. The current collectors 250 are made of aluminum, an aluminum alloy, copper, a copper alloy, or the like. The gaskets 230 and 240 are flat, insulating sealing members arranged between the container lid 212 and the electrode terminal 220 and the current collectors 250. The gaskets 230 and 240 are made of any insulating resin material that can be used for the spacer 300.

[0053] [3. Description of the exterior body 100 and the spacer 300] The configurations of the exterior housing 100 (first exterior housing 110 and second exterior housing 120) and the spacer 300 (first spacer 310 and second spacer 320) will be described in detail. FIG. 5 is a perspective view showing a part of the exterior housing 100 (first exterior housing 110 and second exterior housing 120) according to the present embodiment, which is a configuration for accommodating the energy storage element 200. Specifically, (a) of FIG. 5 is a perspective view showing the configuration of the first exterior housing 110 when viewed from above, and (b) of FIG. 5 is a perspective view showing the configuration of a part of the second exterior housing 120 (a portion for accommodating the energy storage element 200) when viewed from below. Hereinafter, the part of the second exterior housing 120 (a portion for accommodating the energy storage element 200) shown in (b) of FIG. 5 will be described as the second exterior housing 120.

[0054] 6 is a perspective view showing the configuration of a spacer 300 (first spacer 310 and second spacer 320) according to this embodiment. Specifically, FIG. 6(a) is a perspective view showing the configuration of the first spacer 310 when viewed from below, and FIG. 6(b) is a perspective view showing the configuration of the second spacer 320 in the negative Z-axis direction when viewed from above. Note that the pair of second spacers 320 have the same configuration (shapes that are plane-symmetrical with respect to the XY plane), and therefore the second spacer 320 in the positive Z-axis direction is not shown in FIG.

[0055] Fig. 7 is a cross-sectional view showing the positional relationship between the exterior housing 100 (first exterior housing 110 and second exterior housing 120) and the spacer 300 (first spacer 310 and second spacer 320) according to the present embodiment. Specifically, Fig. 7(a) shows a cross-section of the energy storage unit 10 taken along a plane that passes through the third connecting portion 112 of the first exterior housing 110 and the fourth connecting portion 122 of the second exterior housing 120 and is parallel to the XZ plane. Fig. 7(b) to (d) show enlarged views of the areas surrounded by dashed lines at the end in the negative X-axis direction, the center in the X-axis direction, and the end in the positive X-axis direction in Fig. 7(a).

[0056] 3.1 Description of the First Exterior Body 110 and the Second Exterior Body 120 As shown in FIG. 5 , the first exterior body 110 has connecting portions 111 and 112 and an engaging portion 113. The second exterior body 120 has an upper wall 120a, a pair of long side walls 120b, and a pair of short side walls 120c and 120d. The pair of long side walls 120b and the pair of short side walls 120c and 120d are provided with connecting portion 121 and engaging portion 123, and the upper wall 120a is provided with connecting portions 122 and 124. The long side wall 120b in the negative Y-axis direction is formed with the aforementioned through-hole 125. Hereinafter, the connecting portion 111 will also be referred to as the first connecting portion 111, the connecting portion 121 will also be referred to as the second connecting portion 121, the connecting portion 112 will also be referred to as the third connecting portion 112, and the connecting portion 122 will also be referred to as the fourth connecting portion 122.

[0057] Top wall 120a is a flat, rectangular wall (top wall) located on the positive side of second exterior housing 120 in the Z-axis direction, and is disposed adjacent to long side wall 120b and short side walls 120c and 120d. Long side walls 120b are flat, rectangular wall (side walls) located on both sides of second exterior housing 120 in the Y-axis direction, and are adjacent to top wall 120a and short side walls 120c and 120d, and have a larger outer surface area than short side walls 120c and 120d. Short side walls 120c and 120d are flat, rectangular wall (side walls) located on both sides of second exterior housing 120 in the X-axis direction, and are adjacent to top wall 120a and long side wall 120b, and have a smaller outer surface area than long side wall 120b.

[0058] The first connecting portion 111 is a connecting portion with the second connecting portion 121 that is disposed on the outer periphery of the first exterior housing 110 as viewed from the Z-axis direction (first direction). The outer periphery of the first exterior housing 110 is a portion located near the outer edge of the first exterior housing 110 as viewed from the Z-axis direction, and is, for example, a region within a range of approximately 10-15 mm from the outer edge of the first exterior housing 110. In other words, the first connecting portion 111 is disposed at a position adjacent to the outer edge of the first exterior housing 110 as viewed from the Z-axis direction. The same applies to the expression "outer periphery" below. In this embodiment, 14 first connecting portions 111 are disposed in a ring shape along the outer edge of the first exterior housing 110 around the entire outer periphery of the first exterior housing 110 as viewed from the Z-axis direction (first direction). The second connecting portion 121 is a connecting portion with the first connecting portion 111 that is disposed on the outer periphery of the second exterior housing 120 as viewed from the Z-axis direction (first direction). Similarly, when viewed from the Z-axis direction, 14 second connecting portions 121 are arranged in a ring shape along the outer edge of second exterior body 120 around the entire circumference of the outer periphery (the pair of long side walls 120b and the pair of short side walls 120c, 120d) of second exterior body 120. In this way, first connecting portions 111 and second connecting portions 121 are arranged in corresponding (opposing) positions on the outer peripheries of first exterior body 110 and second exterior body 120, and are connected (joined) to each other.

[0059] Specifically, the first connecting portion 111 and the second connecting portion 121 are joined by a joining member 130 (see FIG. 7). In this embodiment, the first connecting portion 111 has a through-hole formed therein that is circular in top view (as viewed from the Z-axis direction), and the second connecting portion 121 has a female thread portion formed therein. The joining member 130 is a screw (bolt) having a male thread portion formed therein. With this configuration, the male thread portion of the joining member 130 passes through the through-hole of the first connecting portion 111 and screws into the female thread portion of the second connecting portion 121, thereby fixing the joining member 130 to the second connecting portion 121 and joining the first connecting portion 111 and the second connecting portion 121 together. In this embodiment, the first connecting portion 111 and the second connecting portion 121 are joined together in a state of abutting each other in the Z-axis direction (see FIG. 7). This joins the outer periphery of first exterior body 110 and the outer periphery of second exterior body 120 (the pair of long side walls 120b and the pair of short side walls 120c, 120d), connecting (fixing) first exterior body 110 and second exterior body 120. Note that a sealing member (gasket, packing) or the like may be interposed between first connecting portion 111 and second connecting portion 121.

[0060] The third connecting portion 112 is a connecting portion with the fourth connecting portion 122, and is disposed inside the outer periphery of the first external housing 110 as viewed from the Z axis direction (first direction). "Inside the outer periphery of the first external housing 110" means a position farther from the outer edge of the first external housing 110 than the outer periphery as viewed from the Z axis direction, for example, a position more than about 10 mm away from the outer edge of the first external housing 110. In other words, the third connecting portion 112 is disposed at a position sandwiching the outer periphery between the outer edge of the first external housing 110 as viewed from the Z axis direction. The same applies to the expression "inside the outer periphery" below. The third connecting portion 112 is disposed at a position including the center of the first external housing 110 as viewed from the Z axis direction (first direction). In the present embodiment, ten third connecting portions 112 are disposed in a grid pattern in the X axis direction and the Y axis direction, inside the first connecting portion 111 as viewed from the Z axis direction. Specifically, two third connection parts 112 aligned in the Y-axis direction are arranged at both end parts in the X-axis direction, at the center, and between both end parts and the center of the first external housing 110. As a result, the third connection parts 112 are arranged at positions sandwiching each of the energy storage elements 200 aligned in the X-axis direction in the X-axis direction (between the energy storage elements 200 aligned in the X-axis direction) (see FIG. 7).

[0061] The fourth connection portion 122 is a connection portion with the third connection portion 112, and is disposed inside the outer periphery of the second external housing 120 as viewed from the Z axis direction (first direction). The fourth connection portion 122 is disposed at a position including the center of the second external housing 120 as viewed from the Z axis direction (first direction). In the present embodiment, ten fourth connection portions 122 are disposed in a lattice pattern in the X axis direction and the Y axis direction on the upper wall 120a located inside the second connection portion 121 as viewed from the Z axis direction. Specifically, two fourth connection portions 122 aligned in the Y axis direction are disposed at both end portions, the center portion, and a portion between both end portions and the center portion of the upper wall 120a in the X axis direction. As a result, the fourth connection portions 122 are disposed at positions sandwiching the energy storage elements 200 aligned in the X axis direction in the X axis direction (between the energy storage elements 200 aligned in the X axis direction) (see FIG. 7 ). In this way, the third connecting portion 112 and the fourth connecting portion 122 are arranged in corresponding (opposing) positions inside the outer peripheries of the first outer casing 110 and the second outer casing 120, and are connected (joined) to each other.

[0062] Specifically, the third connecting portion 112 and the fourth connecting portion 122 are joined by a joining member 140 (see FIG. 7). In this embodiment, the third connecting portion 112 has a through-hole that is circular in top view (as viewed from the Z-axis direction), and the fourth connecting portion 122 has a female thread portion. The joining member 140 is a screw (bolt) having a male thread portion. With this configuration, the male thread portion of the joining member 140 passes through the through-hole of the third connecting portion 112, is inserted into the cylindrical collar 150, and screws into the female thread portion of the fourth connecting portion 122. This fixes the joining member 140 to the fourth connecting portion 122, and joins the third connecting portion 112 and the fourth connecting portion 122 together. In this embodiment, the third connecting portion 112 and the fourth connecting portion 122 are joined together while being spaced apart from each other in the Z-axis direction, with the collar 150 sandwiched between them (see FIG. 7). In this way, the inside of the outer periphery of first exterior body 110 and the inside of the outer periphery of second exterior body 120 are joined, thereby connecting (fixing) first exterior body 110 and second exterior body 120. Note that a configuration in which collar 150 is not disposed in the joining by joining member 140 is also possible.

[0063] In at least one of the third connecting portion 112 and the fourth connecting portion 122, the joining member 140 joining the third connecting portion 112 and the fourth connecting portion 122 is disposed in a position where it is not exposed to the outside (see FIG. 7 ). In this embodiment, the female thread portion of the fourth connecting portion 122 does not penetrate the fourth connecting portion 122 in the Z-axis direction, and therefore the joining member 140 is disposed in a position in the fourth connecting portion 122 where it is not exposed to the outside. The joining member 140 is, for example, a bolt (sealing bolt) that can seal the through-hole of the third connecting portion 112 when joined to the fourth connecting portion 122. As a result, airtightness is ensured in the third connecting portion 112 by the joining member 140 sealing the through-hole, and airtightness is ensured in the fourth connecting portion 122 because the joining member 140 is not exposed to the outside.

[0064] The engagement portions 113 are circular through-holes in a top view (viewed from the Z-axis direction) that are disposed at both ends in the X-axis direction (both ends of the outer periphery) of the first exterior body 110. The engagement portions 123 are cylindrical protrusions that are disposed at both ends in the X-axis direction of the second exterior body 120 (both ends of the outer periphery, a pair of short side walls 120c and 120d). The engagement portions 113 and 123 are disposed at positions that correspond to (face) each other, and the first exterior body 110 and the second exterior body 120 are positioned such that the engagement portion 123 is inserted into the engagement portion 113 and engages with each other. The connection portion 124 is disposed at both ends in the X-axis direction of the top wall 120a of the second exterior body 120 (both ends that are more inward than the outer periphery), and is a portion to which a connection portion 315 of a first spacer 310 (described later) is connected. In this embodiment, a female thread portion is formed in the connection portion 124, and the male thread portion of the joining member (not shown) passes through the through hole of the connection portion 315 and screws into the female thread portion of the connection portion 124, thereby joining the first spacer 310 to the second outer casing 120.

[0065] In addition to the above configuration, in the first exterior body 110, in order to improve strength and suppress swelling of the energy storage element 200, protrusions (bulges) that are rectangular in top view and protrude in the positive direction of the Z axis toward the energy storage element 200 are formed over the entire surface of the first exterior body 110. The position, shape, and number of the protrusions (bulges) of the first exterior body 110 are not particularly limited, and the first exterior body 110 may be configured without any protrusions (bulges).

[0066] 3.2 Explanation of the First Spacer 310 and the Second Spacer 320 6, the first spacer 310 has a first spacer body 311, a first spacer wall 312, a first protruding portion 313, and connecting portions 314 and 315. The second spacer 320 has a second spacer body 321, a second spacer wall 322, and a second protruding portion 323.

[0067] The first spacer body 311 is a flat, rectangular portion that is parallel to the XY plane and that constitutes the body of the first spacer 310, and is disposed so as to extend in the X-axis direction. The first spacer body 311 is disposed at a position facing the long side surfaces 211a of the containers 210 of the four energy storage elements 200 that are aligned in the X-axis direction, and abuts against the long side surfaces 211a of the four energy storage elements 200. The first spacer wall portion 312 is a flat, rectangular side wall that protrudes from both end edges of the first spacer body 311 in the X-axis direction and both end edges of the first spacer body 311 in the Y-axis direction to both sides in the Z-axis direction, so as to surround the periphery of the first spacer body 311. The first spacer wall portion 312 is disposed so as to cover the short side surfaces 211b and bottom surfaces 211c of the containers 210 of the opposing energy storage elements 200, as well as part of the container lid 212.

[0068] The first protrusions 313 are elongated protruding portions that protrude from the first spacer main body 311 toward the pair of second spacers 320 on both sides in the Z-axis direction and extend in the Y-axis direction (a third direction intersecting the first and second directions). Specifically, the first protrusions 313 protrude toward and are disposed between the plurality of energy storage elements 200. That is, the first protrusions 313 protrude toward and are disposed between two adjacent energy storage elements 200 among the plurality of energy storage elements 200 aligned in the X-axis direction. In this embodiment, three first protrusions 313 are disposed for four energy storage elements 200 aligned in the X-axis direction. The first protrusions 313 are disposed so as to extend from one end to the other end of the first spacer main body 311 in the Y-axis direction. That is, the first protrusion 313 is arranged to extend from one end to the other end of the plurality of energy storage elements 200 (two energy storage elements 200 sandwiching the first protrusion 313) in the Y-axis direction (third direction).

[0069] The first protrusion 313 has a first through hole 313a and a positioning portion 313b. The first through hole 313a is a circular through hole that penetrates the first protrusion 313 in the Z axis direction and is viewed from the Z axis direction, and the joining member 140 (and the collar 150) is inserted into the first protrusion 313 (see FIG. 7). Two first through holes 313a are formed in each first protrusion 313 at positions corresponding to the two joining members 140 (and the third connecting portion 112 and the fourth connecting portion 122). As a result, the joining member 140 is disposed between the plurality of energy storage elements 200, and the inner walls of the first through holes 313a in the first protrusion 313 cover the periphery of the joining member 140. The positioning portions 313b are disposed at both ends of the first protrusion 313 in the Y axis direction and have rectangular through holes that penetrate the first protrusion 313 in the Z axis direction and are viewed from the Z axis direction. The positioning portion 313b is a portion that engages (fits) with a positioning portion 323b of the second protruding portion 323, which will be described later.

[0070] The connecting portions 314 are portions that connect (fix) the first spacer 310 to the exterior housing 100 (the first exterior housing 110 and the second exterior housing 120) at both ends of the first spacer 310 in the X axis direction. The connecting portions 314 have through-holes that penetrate in the Z axis direction and are circular when viewed from the Z axis direction, and the joining members 140 (and the collar 150) are inserted into the through-holes (see FIG. 7 ). At each of the both ends of the first spacer 310 in the X axis direction, two connecting portions 314 are arranged at positions corresponding to the two joining members 140 (as well as the third connecting portion 112 and the fourth connecting portion 122). As described above, the connecting portions 315 are portions that connect (fix) the first spacer 310 to the second exterior housing 120, and are arranged at both ends of the first spacer 310 in the X axis direction.

[0071] The second spacer main body 321 is a flat, rectangular portion parallel to the XY plane that constitutes the main body of the second spacer 320, and is disposed so as to extend in the X-axis direction. The second spacer main body 321 is disposed at a position facing the long side surfaces 211a of the containers 210 of the four energy storage elements 200 aligned in the X-axis direction, and abuts against the long side surfaces 211a of the four energy storage elements 200. The second spacer wall portion 322 is a flat, rectangular side wall that protrudes from both end edges of the second spacer main body 321 in the X-axis direction and both end edges of the second spacer main body 321 toward the first spacer 310 so as to surround the periphery of the second spacer main body 321. The second spacer wall portion 322 is disposed so as to cover, together with the first spacer wall portion 312, almost the entire short side surfaces 211b and bottom surfaces 211c of the containers 210 of the opposing energy storage elements 200, as well as part of the container lid 212.

[0072] The second protrusion 323 is an elongated protruding portion that protrudes from the second spacer main body 321 toward the first protrusion 313 of the first spacer 310 in the Z-axis direction and extends in the Y-axis direction (third direction). Specifically, the second protrusion 323 protrudes toward a gap between the plurality of energy storage elements 200 and is disposed between the plurality of energy storage elements 200. That is, the second protrusion 323 protrudes toward a gap between two adjacent energy storage elements 200 among the plurality of energy storage elements 200 aligned in the X-axis direction and is disposed between the two energy storage elements 200. In this embodiment, three second protrusions 323 are disposed for three first protrusions 313 aligned in the X-axis direction. The second protrusions 323 are disposed so as to extend from one end to the other end of the second spacer main body 321 in the Y-axis direction. That is, the second protrusion 323 is arranged to extend from one end to the other end of the plurality of energy storage elements 200 (two energy storage elements 200 sandwiching the second protrusion 323) in the Y-axis direction (third direction).

[0073] The second protruding portion 323 has a second through hole 323a and a positioning portion 323b. The second through hole 323a is a through hole that penetrates the second protruding portion 323 in the Z-axis direction and has a circular shape when viewed from the Z-axis direction, and the joining member 140 (and the collar 150 or the fourth connecting portion 122) is inserted into the second protruding portion 323 (see FIG. 7). Two second through holes 323a are formed in each second protruding portion 323 at positions corresponding to the first through holes 313a of the first protruding portion 313, i.e., at positions corresponding to the two joining members 140 (and the third connecting portion 112 and the fourth connecting portion 122). As a result, the joining member 140 is disposed between the plurality of energy storage elements 200, and the inner walls of the second through holes 323a in the second protruding portion 323 cover the periphery of the joining member 140.

[0074] 7 , the first protruding portion 313 and the second protruding portion 323 are disposed between the third connecting portion 112 of the first exterior housing 110 and the fourth connecting portion 122 of the second exterior housing 120. The joining member 140 passes through the first through hole 313a of the first protruding portion 313 and the second through hole 323a of the second protruding portion 323, thereby joining the third connecting portion 112 and the fourth connecting portion 122. As described above, the first exterior housing 110 and the second exterior housing 120 can also be considered to be a pair of end plates, and therefore the joining member 140 can also be considered to be disposed in a state of passing through the first protruding portion 313 and the second protruding portion 323, thereby joining the pair of end plates. In this way, a portion of the spacer 300 is positioned between the third connecting portion 112 and the fourth connecting portion 122, and a through hole is formed in that portion, and the joining member 140 joins the third connecting portion 112 and the fourth connecting portion 122 while passing through the through hole.

[0075] In the present embodiment, the fourth connecting portion 122 is inserted into the second through hole 323a of the second protruding portion 323 of the second spacer 320 in the positive direction of the Z axis, but may not be inserted into the second through hole 323a. The third connecting portion 112 may be inserted into the second through hole 323a of the second protruding portion 323 of the second spacer 320 in the negative direction of the Z axis.

[0076] The positioning portions 323b are disposed at both ends of the second protrusion 323 in the Y axis direction, and are rectangular convex portions when viewed from the Z axis direction, protruding from the second protrusion 323 toward the positioning portions 313b of the first protrusion 313. The positioning portions 323b are inserted into the through holes of the positioning portions 313b and engage (fit) with the positioning portions 313b, thereby determining the relative positions of the first protrusion 313 and the second protrusion 323. In other words, the positioning portions 313b and 323b determine the positions of the first protrusion 313 and the second protrusion 323 in the X axis direction and the Y axis direction. In this embodiment, the positioning portion 323b has a through hole formed therethrough in the Z axis direction. This allows, for example, the state of the portions of the positioning portions 313b and 323b in the negative Z axis direction to be ascertained by viewing the positioning portions 313b and 323b from the positive Z axis direction.

[0077] [4. Explanation of effects] According to the energy storage device 1 of the embodiment of the present invention, the exterior body 100 that houses the energy storage element 200 has a first exterior body 110 and a second exterior body 120 that sandwich and restrain the energy storage element 200. The first exterior body 110 and the second exterior body 120 have a first connection portion 111 and a second connection portion 121 that are joined in an abutting state at their outer peripheries, and a third connection portion 112 and a fourth connection portion 122 that are joined by a joining member 140 in a spaced-apart state on the inside of the outer periphery. In this way, by restraining the energy storage element 200 with the exterior body 100 (the first exterior body 110 and the second exterior body 120) that houses the energy storage element 200, the energy storage element 200 can be restrained without disposing end plates. Furthermore, when the exterior housing 100 is used to restrain the energy storage element 200, there is a risk that the energy storage element 200 may not be firmly restrained. Therefore, the first exterior housing 110 and the second exterior housing 120 are joined not only at abutting positions (outer peripheries) but also at spaced positions (inner than the outer peripheries). This allows the exterior housing 100 (first exterior housing 110 and second exterior housing 120) to firmly sandwich and restrain the energy storage element 200. Therefore, even without disposing end plates, the exterior housing 100 (first exterior housing 110 and second exterior housing 120) can firmly sandwich and restrain the energy storage element 200, thereby reducing the number of parts. Reducing the number of parts allows for weight reduction, size reduction, cost reduction, and improved productivity.

[0078] Because a portion of the spacer 300 (first protruding portion 313 and second protruding portion 323) is disposed between the third connecting portion 112 and the fourth connecting portion 122, through holes (first through hole 313a and second through hole 323a) are formed in the portion to join the third connecting portion 112 and the fourth connecting portion 122. Then, the joining member 140 is passed through the through holes to join the third connecting portion 112 and the fourth connecting portion 122. This allows the first exterior body 110 and the second exterior body 120 to be firmly joined together even when a portion of the spacer 300 is disposed between the third connecting portion 112 and the fourth connecting portion 122. Therefore, the energy storage device 200 can be firmly sandwiched and restrained by the exterior body 100 (first exterior body 110 and second exterior body 120) without disposing an end plate, thereby reducing the number of parts.

[0079] Because the third connecting portion 112 and the fourth connecting portion 122 are disposed in the central portions of the first exterior body 110 and the second exterior body 120, the first exterior body 110 and the second exterior body 120 are joined at their central portions. This allows the first exterior body 110 and the second exterior body 120 to be firmly joined. Therefore, even without arranging end plates, the energy storage device 200 can be firmly sandwiched and restrained by the exterior body 100 (the first exterior body 110 and the second exterior body 120), thereby reducing the number of parts.

[0080] At least one of the third connecting portion 112 and the fourth connecting portion 122 (in this embodiment, the fourth connecting portion 122) has the joining member 140 not exposed to the outside, thereby improving the airtightness of the outer casing 100 and saving space.

[0081] The first exterior housing 110 and the second exterior housing 120 sandwich and restrain the plurality of energy storage elements 200 arranged in a direction (X-axis direction) intersecting the stacking direction of the electrode plates (Z-axis direction) in the stacking direction of the electrode plates. In this way, even when the plurality of energy storage elements 200 are arranged (arranged side by side) in a direction intersecting the stacking direction of the electrode plates, the first exterior housing 110 and the second exterior housing 120 can collectively restrain the plurality of energy storage elements 200. This allows for a reduction in the number of parts compared to restraining the plurality of energy storage elements 200 individually.

[0082] The energy storage device 1 according to the embodiment of the present invention includes a first spacer 310 and a second spacer 320 arranged across the energy storage elements 200 at positions sandwiching the energy storage elements 200 arranged in the second direction (X-axis direction). The first spacer 310 extends in the third direction (Y-axis direction) and has a first protrusion 313 protruding between the energy storage elements 200, and the second spacer 320 extends in the third direction and has a second protrusion 323 protruding toward the first protrusion 313. In this manner, the first spacer 310 and the second spacer 320 are arranged on both sides of the energy storage elements 200, thereby improving insulation between the energy storage elements 200 on both sides. The first protrusion 313 of the first spacer 310 and the second protrusion 323 of the second spacer 320 are arranged to extend between the energy storage elements 200, thereby improving insulation between the energy storage elements 200. As a result, the insulation between the energy storage elements 200 can be improved.

[0083] Since the energy storage elements 200 aligned in the X-axis direction are spaced apart from each other, heat transfer between the energy storage elements 200 is suppressed, and it is possible to suppress mutual thermal influence between the energy storage elements 200. Since the first spacer 310 and the second spacer 320 are arranged across the multiple energy storage elements 200 aligned in the X-axis direction, the number of parts can be reduced compared to a configuration in which the first spacer 310 and the second spacer 320 are arranged for each energy storage element 200.

[0084] By extending the first protruding portion 313 of the first spacer 310 and the second protruding portion 323 of the second spacer 320 from one end to the other end in the third direction of the plurality of energy storage elements 200, it is possible to further improve the insulation between the plurality of energy storage elements 200. This makes it possible to improve the insulation of the energy storage elements 200.

[0085] The first protruding portion 313 of the first spacer 310 and the second protruding portion 323 of the second spacer 320 have the positioning portions 313b and 323b, which allows the first spacer 310 and the second spacer 320 to be positioned relative to each other. This makes it possible to prevent the first spacer 310 or the second spacer 320 from moving relative to the energy storage elements 200. This improves the insulation of the energy storage elements 200. The first spacer 310 and the second spacer 320 are arranged across the multiple energy storage elements 200 lined up in the X-axis direction, so the number of positioning portions 313b and 323b to be arranged can be reduced compared to a configuration in which the first spacer 310 and the second spacer 320 are arranged for each energy storage element 200.

[0086] A first exterior housing 110 and a second exterior housing 120 are arranged as a pair of end plates across the multiple energy storage elements 200 lined up in the X-axis direction, at positions sandwiching the multiple energy storage elements 200, the first spacer 310, and the second spacer 320. As a result, even if the first exterior housing 110 and the second exterior housing 120 are formed of a conductive material such as metal, the first spacer 310 and the second spacer 320 can improve insulation between the multiple energy storage elements 200 and the first exterior housing 110 and the second exterior housing 120. This can improve the insulation of the energy storage elements 200. Because the multiple energy storage elements 200 can be sandwiched collectively by the first exterior housing 110 and the second exterior housing 120 as a pair of end plates, the number of parts can be reduced compared to a configuration in which a pair of end plates is arranged for each energy storage element 200.

[0087] The joining member 140, which joins the first exterior body 110 and the second exterior body 120 as a pair of end plates, is disposed so as to penetrate the first protrusion 313 and the second protrusion 323. This makes it possible to prevent the energy storage element 200 from becoming electrically conductive with the joining member 140, even when the joining member 140 is formed of a conductive material such as metal. Therefore, electrical conduction between the energy storage element 200 and the first exterior body 110 and the second exterior body 120 via the joining member 140 can be prevented, thereby improving the insulation of the energy storage element 200. By disposing the joining member 140 so as to penetrate the first protrusion 313 and the second protrusion 323, the first exterior body 110 and the second exterior body 120 can be joined between a plurality of energy storage elements 200, thereby enabling the first exterior body 110 and the second exterior body 120 to be firmly joined. This reduces the need to thicken the first exterior body 110 or the second exterior body 120 as end plates or to form them from high-strength materials, thereby enabling reductions in size, weight, cost, etc. of the energy storage device 1. The first exterior body 110 and the second exterior body 120 as a pair of end plates are arranged across multiple energy storage elements 200 lined up in the X-axis direction, so the number of joining members 140 to be arranged can be reduced compared to a configuration in which a pair of end plates is arranged for each energy storage element 200.

[0088] [5. Explanation of Variations] Although the energy storage device 1 according to the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. The embodiment disclosed herein is illustrative in all respects and is not restrictive, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0089] In the above embodiment, in the exterior housing 100, the second exterior housing 120 is a bottomed rectangular tubular member having an opening formed on the negative Z-axis direction side, and the first exterior housing 110 is a flat rectangular member that closes the opening of the second exterior housing 120. However, the first exterior housing 110 may be a bottomed rectangular tubular member having an opening formed on the positive Z-axis direction side, and the second exterior housing 120 may be a flat rectangular lid that closes the opening of the first exterior housing 110, or may have any other shape.

[0090] In the above embodiment, a through hole is formed in first connecting portion 111 of first exterior housing 110, and a female thread portion that screws onto the male thread portion of joining member 130 is formed in second connecting portion 121 of second exterior housing 120. However, a through hole may be formed in second connecting portion 121, and a female thread portion that screws onto the male thread portion of joining member 130 may be formed in first connecting portion 111. The method of connecting (joining) first connecting portion 111 and second connecting portion 121 may be other methods, such as riveting, crimping, clipping, adhesion, welding, heat sealing, ultrasonic welding, etc. The same applies to third connecting portion 112 and fourth connecting portion 122.

[0091] In the above embodiment, the third connecting portion 112 and the fourth connecting portion 122 are arranged in the central portions of the first exterior body 110 and the second exterior body 120, but they do not have to be arranged in these central portions. By increasing the plate thickness of the first exterior body 110 and the second exterior body 120, for example, it is possible to realize a configuration in which the first exterior body 110 and the second exterior body 120 firmly sandwich and restrain the energy storage element 200, even if the third connecting portion 112 and the fourth connecting portion 122 are not arranged in the central portions.

[0092] In the above embodiment, the joining member 140 is arranged at a position in the fourth connection portion 122 where it is not exposed to the outside, and the joining member 140 is exposed to the outside in the third connection portion 112. However, instead of or in addition to the fourth connection portion 122, the joining member 140 may be configured not to be exposed to the outside in the third connection portion 112. Both the third connection portion 112 and the fourth connection portion 122 may be configured so that the joining member 140 is exposed to the outside.

[0093] In the above embodiment, the first protruding portion 313 of the first spacer 310 and the second protruding portion 323 of the second spacer 320 extend from one end to the other end in the third direction of the energy storage element 200. However, at least one of the first protruding portion 313 and the second protruding portion 323 may be shorter than the length from one end to the other end in the third direction of the energy storage element 200.

[0094] In the above embodiment, the first protruding portion 313 and the second protruding portion 323 do not necessarily have to have the positioning portions 313b and 323b.

[0095] In the above embodiment, all of the first connecting portions 111 and third connecting portions 112 of the first outer casing 110, and all of the second connecting portions 121 and fourth connecting portions 122 of the second outer casing 120, have the above configuration, but any of the portions may not have the above configuration.

[0096] In the above embodiment, all of the first protrusions 313 of the first spacer 310 and all of the second protrusions 323 of the second spacer 320 have the above configuration, but any of the portions may not have the above configuration.

[0097] The energy storage device 1 does not need to include all of the above-described components. For example, the energy storage device 1 does not need to include the control unit 20, the terminal unit 30, the bus bar plate 400, the bus bar cover 600, or the like.

[0098] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0099] The present invention can be realized not only as the energy storage device 1, but also as the exterior body 100 (first exterior body 110 and second exterior body 120) or a combination of the exterior body 100 and the spacer 300. [Industrial Applicability]

[0100] 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]

[0101] 1. Energy storage device 21, 31a External terminal 31, 500, 510, 520, 530 busbars 100 exterior body 110 First exterior body 111 First connection part (connection part) 112 Third connection part (connection part) 120 Second exterior body 121 Second connection part (connection part) 122 Fourth Connection (Connection) 124, 314, 315 Connections 130, 140 Joint members 150 colors 200, 201, 202, 203, 204, 205, 206, 207, 208 Storage elements 210 Container 220 Electrode terminal 230, 240 Gasket 250 current collector 260 Electrode body 300 spacer 310 First spacer 311 First spacer body 312 first spacer wall portion 313 First protrusion 313a First through hole 313b, 323b Positioning part 320 Second spacer 321 Second spacer body 322 Second spacer wall 323 Second protrusion 323a Second through hole 400 Busbar Plate 600 Busbar Cover

Claims

1. An electricity storage device including an electricity storage element and an exterior body in which the electricity storage element is housed, The outer casing is a first exterior body and a second exterior body that are arranged side by side in a first direction and joined to each other to sandwich and restrain the energy storage element in the first direction; The first exterior body and the second exterior body a first connecting portion and a second connecting portion that are arranged on outer peripheries of the first exterior body and the second exterior body and are joined in abutting contact with each other when viewed from the first direction; a third connection portion and a fourth connection portion that are arranged inside the outer circumferential portion when viewed from the first direction and are joined to each other, the third connection portion and the fourth connection portion are joined by a joining member while being spaced apart from each other, further comprising a spacer arranged alongside the energy storage element in the first direction; a portion of the spacer is disposed between the third connection portion and the fourth connection portion, and a through hole is formed in the portion; The joining member joins the third connecting portion and the fourth connecting portion in a state where the joining member passes through the through hole. Energy storage device.

2. The third connection portion and the fourth connection portion are disposed at the center portions of the first exterior body and the second exterior body when viewed from the first direction. The power storage device according to claim 1 .

3. In at least one of the third connection portion and the fourth connection portion, a joining member that joins the third connection portion and the fourth connection portion is disposed at a position that is not exposed to the outside. The electricity storage device according to claim 1 or 2.

4. the energy storage element has an electrode body in which electrode plates are stacked in the first direction, and a plurality of the energy storage elements are arranged in a second direction intersecting the first direction, The first external housing and the second external housing sandwich and restrain the plurality of energy storage elements in the first direction. The electricity storage device according to any one of claims 1 to 3.

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