Electric storage device

Abstract

To provide a power storage device which can prevent damage to power storage elements.SOLUTION: A power storage device 10 comprises: a plurality of power storage elements 200 each of which has a container body 220, and a lid 230 for closing the container body 220 and welded to the container body 220; a pair of end plates 400 which sandwich, in a predetermined direction, the plurality of power storage elements 200 aligned in the predetermined direction; and coupling parts which are provided to extend along the predetermined direction and are coupled to the pair of end plates. In at least one of the pair of end plates, a portion which overlaps a welding part 260 between the container body 220 and the lid 230 when viewed in the predetermined direction (an X-axis direction) serves as a first protrusion 438 protruding to the side opposite to the power storage elements 200.SELECTED DRAWING: Figure 9

Description

Technical Field

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

Background Art

[0002] Conventionally, a power storage device is known in which a plurality of power storage elements such as lithium ion batteries are housed in a pair of divided exterior bodies, and the connection surfaces of the pair of exterior bodies are thermally welded together. In such a power storage device, a pair of flat end plates arranged at positions sandwiching a plurality of power storage elements are also housed in the exterior body (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Power storage elements have the characteristic of gradually expanding as they are charged and discharged. Therefore, if the expansion of a plurality of power storage elements progresses, there is a risk that the power storage elements will be damaged.

[0005] An object of the present invention is to provide a power storage device capable of suppressing damage to power storage elements.

Means for Solving the Problems

[0006] In order to achieve the above-mentioned object, an energy storage device according to one embodiment of the present invention comprises a plurality of energy storage elements having a container body and a lid body that closes the container body and is welded to the container body, a pair of end plates that sandwich the plurality of energy storage elements arranged in a predetermined direction in a predetermined direction, and a connecting portion that extends along the predetermined direction and is connected to the pair of end plates, and at least one of the pair of end plates has a first protrusion that protrudes toward the opposite side of the energy storage elements at a portion that overlaps the weld portion between the container body and the lid body when viewed in the predetermined direction.

[0007] According to this, at least one of the end plates is provided with a first protrusion, which increases the rigidity of the end plate itself. This allows the end plate 400 to suppress expansion of the energy storage element 200, thereby suppressing damage to the energy storage element 200 caused by the expansion. In particular, the welded portion between the container body and the lid of the energy storage element is weaker than other portions, and therefore the welded portion is easily damaged when the energy storage element expands. Therefore, in this embodiment, a portion of at least one of the end plates that overlaps the welded portion of the energy storage element is provided as the first protrusion. This allows the first protrusion of the end plate to suppress the expansion of the welded portion even if the welded portion of the energy storage element attempts to expand. Therefore, damage to the energy storage element can be suppressed.

[0008] Here, if the first protrusion protrudes toward the energy storage element, for example, if the end plate is deformed by an external impact, the first protrusion may come into contact with the welded portion of the energy storage element. As described above, the welded portion is a weak point, and therefore is more likely to be damaged by the first protrusion than other portions. In this embodiment, because the first protrusion protrudes toward the side opposite the energy storage element, even if the end plate is deformed, the first protrusion is less likely to come into contact with the welded portion of the energy storage element. Therefore, damage to the energy storage element can be suppressed even if the end plate is deformed.

[0009] At least one of the end plates may have a first plate having a first protrusion and a second plate disposed between the first plate and the plurality of power storage elements and overlapping the first plate.

[0010] According to this, since it is an end plate in which the first plate and the second plate overlap, the rigidity of the end plate itself can be increased. Therefore, the expansion of the power storage element can be more reliably suppressed, and the damage to the power storage element can be more suppressed.

[0011] The first plate may have a plurality of concave portions recessed in a direction opposite to the first protrusion and at least one convex portion protruding in the same direction as the first protrusion between adjacent concave portions, and the second plate may have a flat plate portion that abuts against all of the plurality of concave portions.

[0012] According to this, since the first plate has a concavo-convex structure composed of a plurality of concave portions and at least one convex portion, the rigidity of the first plate can be further increased. Thereby, it is possible to increase the rigidity of the end plate itself. On the other hand, the second plate has a flat plate portion that abuts against all of the plurality of concave portions of the first plate. For example, when the first plate receives an external impact, stress is transmitted from each concave portion to the flat plate portion, but since the flat plate portion abuts against all of the plurality of concave portions, the stress can be dispersed. Therefore, it is possible to prevent a large stress from being applied to the power storage element. By these things, the damage to the power storage element can be more suppressed.

[0013] The second plate may have a second protrusion that protrudes in the same direction as the first protrusion and extends in a direction intersecting a predetermined direction.

[0014] According to this, since the second protrusion is provided on the second plate, the rigidity of the second plate itself can be increased. Thereby, the rigidity of the end plate itself is increased. Therefore, the expansion of the power storage element can be more reliably suppressed, and the damage to the power storage element can be more suppressed.

[0015] The first protrusion may extend continuously over the entire length of one edge of the first plate.

[0016] In this case, the first protrusion extends continuously along the entire length of one edge of the first plate, thereby increasing the rigidity of the first plate itself. This increases the rigidity of the end plate itself. Therefore, expansion of the energy storage element can be more reliably suppressed, and damage to the energy storage element can be more effectively suppressed. [Effects of the Invention]

[0017] According to the electricity storage device of the present invention, damage to the electricity storage elements can be suppressed. [Brief explanation of the drawings]

[0018] [Figure 1] 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 each component of the electricity storage device according to the embodiment. [Figure 3] FIG. 2 is an exploded perspective view showing the components of the electricity storage device according to the embodiment when the device is further disassembled. [Figure 4] FIG. 1 is a perspective view showing a configuration of an energy storage element according to an embodiment. [Figure 5] FIG. 2 is an exploded perspective view showing the configuration of an end plate according to the embodiment. [Figure 6] FIG. 2 is an exploded perspective view showing the configuration of an end plate according to the embodiment. [Figure 7] FIG. 4 is a plan view showing a second plate according to the embodiment. [Figure 8] FIG. 2 is a perspective view showing a configuration of an end spacer according to the embodiment. [Figure 9] 4 is a cross-sectional view showing the positional relationship between an end plate, an end spacer, and surrounding members according to the embodiment. FIG. [Figure 10] FIG. 10 is a plan view showing an end spacer according to a modified example. [Figure 11]It is a partial cross-sectional view showing an engagement structure between an end spacer and an exterior body main body according to a modified example. [Figure 12] It is a perspective view showing an end spacer according to a modified example.

Embodiments for Carrying Out the Invention

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

[0020] In the following description and drawings, the arrangement direction of a plurality of power storage elements, the opposing direction of the long side surfaces of the containers of the power storage elements, the arrangement direction of the power storage elements and the intermediate spacers, the arrangement direction of a pair of end plates, and the arrangement direction of a pair of end spacers are defined as the X-axis direction. The arrangement direction of a pair (positive electrode side and negative electrode side) of electrode terminals in one power storage element, the opposing direction of the short side surfaces of the container of the power storage element, or the arrangement direction of a pair of side plates is defined as the Y-axis direction. The arrangement direction of the exterior body main body and the exterior body lid of the power storage device, the arrangement direction of the container main body and the container lid portion of the power storage element, the arrangement direction of the power storage element and the bus bar, or the vertical direction is defined as the Z-axis direction. These X-axis direction, Y-axis direction, and Z-axis direction are directions that intersect (orthogonal in this embodiment) with each other. Note that depending on the usage mode, the Z-axis direction may not be the vertical direction, but hereinafter, for convenience of explanation, the Z-axis direction will be described as the vertical direction.

[0021] In the following description, for example, the positive X-axis direction indicates the arrow direction of the X-axis, and the negative X-axis direction indicates the direction opposite to the positive X-axis direction. The same applies to the Y-axis direction and the Z-axis direction. Furthermore, expressions indicating relative directions or postures such as parallel and orthogonal include cases where they are not strictly in that direction or posture. For example, when two directions are orthogonal, it means not only that the two directions are completely orthogonal, but also that they are substantially orthogonal, that is, for example, including a difference of about several percent.

[0022] (Embodiment) [1 General Description of the Power Storage Device] First, a general description of the power storage device 10 in the present embodiment will be given. FIG. 1 is a perspective view showing the appearance of the power storage device 10 according to the embodiment. FIG. 2 is an exploded perspective view showing each component when the power storage device 10 according to the embodiment is disassembled. FIG. 3 is an exploded perspective view showing each component when the power storage device 10 according to the embodiment is further disassembled. Note that FIG. 3 is an exploded perspective view showing the components other than the exterior body 100 and the bus bar 700 in the power storage device 10.

[0023] The power storage device 10 is a device that can charge electricity from the outside and discharge electricity to the outside. In the present embodiment, it has a substantially rectangular parallelepiped shape. For example, the power storage device 10 is a battery module (battery pack) used for power storage applications or power supply applications, etc. Specifically, the power storage device 10 is used, for example, as a battery for driving a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, or a railway vehicle for electric railways, or for engine starting. Examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and gasoline vehicles. Examples of the above-mentioned railway vehicles for electric railways include trains, monorails, linear motor cars, and hybrid trains equipped with both a diesel engine and an electric motor. Further, the power storage device 10 can also be used as a stationary battery for household or business use, etc.

[0024] As shown in FIG. 1, the power storage device 10 includes an exterior body 100. As shown in FIGS. 2 and 3, inside the exterior body 100, a plurality of power storage elements 200, a plurality of intermediate spacers 300 (310 to 340), a pair of end plates 400 (410, 420), a pair of side plates 500 (501, 502), a bottom plate 600, a plurality of bus bars 700, and a pair of end spacers 800 (810, 820) are accommodated. In addition to the above components, the power storage device 10 may include a bus bar holder 900 (see FIG. 10) on which the bus bar 700 is placed, a circuit board for monitoring the charge and discharge states of the power storage element 200, electrical devices such as fuses, relays, and connectors, and an exhaust portion for exhausting the gas discharged from the power storage element 200 to the outside of the exterior body 100.

[0025] The exterior body 100 is a box-shaped (substantially rectangular parallelepiped shape) container (module case) that constitutes the housing (outer shell) of the power storage device 10. The exterior body 100 is disposed outside a plurality of power storage elements 200, a plurality of intermediate spacers 300, a pair of end plates 400, a pair of side plates 500, a bottom plate 600, and a plurality of bus bars 700, etc., and fixes the plurality of power storage elements 200, etc. at predetermined positions to protect them from impacts and the like. The exterior body 100 is formed of, for example, an insulating member such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene·perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or a composite material thereof, or a metal with insulating coating. Thereby, the exterior body 100 avoids the power storage element 200, etc. from coming into contact with external metal members, etc. Note that if the electrical insulation of the power storage element 200, etc. is maintained, the exterior body 100 may be formed of a conductive member such as metal.

[0026] The exterior body 100 has an exterior body main body 110 that constitutes the main body of the exterior body 100, and an exterior body lid 120 that constitutes the lid of the exterior body 100. The exterior body main body 110 is a rectangular cylindrical housing (chassis) with a bottom and an opening formed at the top, and houses the energy storage element 200 and other components. The exterior body lid 120 is a flat rectangular member that closes the opening of the exterior body main body 110. The exterior body lid 120 is joined to the exterior body main body 110 by adhesive, heat sealing, ultrasonic welding, or the like. The exterior body lid 120 is provided with a pair of external terminals 121 (positive and negative electrode sides). The energy storage device 10 charges with electricity from the outside and discharges electricity to the outside via this pair of external terminals 121.

[0027] The energy storage element 200 is a secondary battery (single cell) capable of charging and discharging electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 200 has a flattened rectangular parallelepiped (rectangular) shape. In this embodiment, eight energy storage elements 200 are arranged side by side in the X-axis direction (a predetermined direction). The size, shape, and number of the energy storage elements 200 to be arranged are not limited, and for example, 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 a capacitor. The energy storage element 200 may not be a secondary battery, but may be a primary battery that allows stored electricity to be used 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.

[0028] The bus bar 700 is a flat and rectangular member connected to the energy storage element 200. The bus bar 700 is disposed above a plurality of energy storage elements 200 and is connected (joined) to the electrode terminals 240 (see FIGS. 2, 4, etc.) of the plurality of energy storage elements 200 and the external terminal 121. That is, the bus bar 700 connects the electrode terminals 240 of the plurality of energy storage elements 200 to each other and connects the electrode terminal 240 of the end energy storage element 200 and the external terminal 121.

[0029] In the present embodiment, the bus bar 700 and the electrode terminal 240 or the external terminal 121 are connected (joined) by welding, but may be connected (joined) by bolt fastening or the like. The bus bar 700 is formed of, for example, a metallic conductive member such as aluminum, an aluminum alloy, copper, a copper alloy, nickel, or a combination thereof, or a conductive member other than a metal. In the present embodiment, the bus bar 700 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. Note that the connection form of the bus bar 700 is not particularly limited, and a plurality of energy storage elements 200 may be connected in series and arranged so as to be connected in parallel in any combination.

[0030] The intermediate spacer 300 is a flat and rectangular member disposed on the side (in the +X-axis direction or the -X-axis direction) of the energy storage element 200 and electrically insulates the energy storage element 200 from other members. The intermediate spacer 300 also has a function of holding the energy storage element 200 and positioning the energy storage element 200. Here, among the plurality of intermediate spacers 300, the intermediate spacers 300 disposed between the energy storage elements 200 (energy storage element groups) are also referred to as intermediate spacers 310 to 330, and the intermediate spacers 300 disposed between the energy storage element 200 (energy storage element group) and the end plate 400 are also referred to as intermediate spacers 340. That is, the plurality of energy storage elements 200 and the plurality of intermediate spacers 300 (intermediate spacers 310 to 340) are arranged side by side in the X-axis direction.

[0031] The intermediate spacers 310 to 330 are disposed between two adjacent power storage elements 200 and are spacers (intermediate spacers) that electrically insulate between the two power storage elements 200. The intermediate spacer 310 is disposed between the intermediate spacers 320 and 330, is thicker and has higher rigidity than the intermediate spacers 320 and 330, and is a spacer. The intermediate spacer 310 is formed of a metal member such as, for example, aluminum, an aluminum alloy, iron, stainless steel, or a plated steel sheet. Note that the material of the intermediate spacer 310 is not particularly limited, and it may be formed of an insulating member having high rigidity, or may be subjected to insulation treatment. The intermediate spacers 320 and 330 are formed of a member having electrical insulation properties such as any resin material that can be used for the above-described exterior body 100, or a member having heat insulation properties such as a damping material.

[0032] The intermediate spacer 340 is disposed between the power storage element 200 at the end and the end plates 400 (410, 420) and is a spacer that electrically insulates between the power storage element 200 at the end and the end plates 400 (410, 420). The intermediate spacer 340 is formed of a member having electrical insulation properties such as any resin material that can be used for the above-described exterior body 100, or a member having heat insulation properties such as a damping material.

[0033] The end plates 400, the side plates 500, and the bottom plate 600 are restraint members that compress (restrain) the power storage elements 200 from the outside in the arrangement direction (X-axis direction) of the plurality of power storage elements 200. That is, the end plates 400, the side plates 500, and the bottom plate 600 sandwich the plurality of power storage elements 200 from both sides in the arrangement direction, thereby compressing (restraining) each power storage element 200 included in the plurality of power storage elements 200 from both sides in the arrangement direction.

[0034] The end plate 400, the side plate 500, and the bottom plate 600 are formed of metal members such as, for example, aluminum, aluminum alloy, iron, stainless steel, and plated steel sheets. Note that the materials of the end plate 400, the side plate 500, and the bottom plate 600 are not particularly limited, and they may be formed of highly rigid insulating members, or may be subjected to insulation treatment.

[0035] Specifically, the end plate 400 is disposed on both sides in the X-axis direction of the plurality of power storage elements 200 and the plurality of intermediate spacers 300 (310 to 340), and is a plate-like member (clamping member) that clamps and holds the plurality of power storage elements 200, etc. from both sides in their arrangement direction (X-axis direction). Here, among the pair of end plates 400, the end plate 400 on the X-axis plus direction side is also referred to as the end plate 410, and the end plate 400 on the X-axis minus direction side is also referred to as the end plate 420. That is, the pair of end plates 410 and 420 are disposed at positions that sandwich the plurality of power storage elements 200 and the plurality of intermediate spacers 300 in the X-axis direction (predetermined direction), and clamp them. Details of the end plate 400 will be described later.

[0036] The side plates 500 and the bottom plate 600 are plate-like members whose both ends are attached to the pair of end plates 400 (410, 420) and connect the pair of end plates 400 to constrain the plurality of power storage elements 200 and the plurality of intermediate spacers 300 (310 to 340). That is, the side plates 500 and the bottom plate 600 are connecting portions that extend in the X-axis direction so as to straddle the plurality of power storage elements 200 and the plurality of intermediate spacers 300 and are connected to the pair of end plates 400. In the present embodiment, a case where the pair of end plates 400 and the bottom plate 600 are provided as the connecting portion is exemplified, but only one of the pair of end plates 400 and the bottom plate 600 may be provided. The side plates 500 and the bottom plate 600 are connected to the pair of end plates 400 to apply a constraining force in their arrangement direction (X-axis direction) to the plurality of power storage elements 200, etc.

[0037] In this embodiment, a pair of side plates 500 are arranged on both sides of the plurality of energy storage elements 200 and the plurality of intermediate spacers 300 (310 to 340) in the Y-axis direction. In this embodiment, the pair of side plates 500 are arranged on both sides of the plurality of energy storage elements 200, etc. in the Y-axis direction, closer to the positive direction of the Z-axis. Each of the pair of side plates 500 is attached to the Y-axis end portions of the pair of end plates 400 at both ends in the X-axis direction. As a result, the pair of side plates 500, together with the pair of end plates 400, sandwich and restrain the plurality of energy storage elements 200, etc. from both sides in the X-axis direction and both sides in the Y-axis direction.

[0038] Specifically, the side plate 500 has a shape in which both end portions in the X-axis direction are bent toward the energy storage device 200. The both end portions of the side plate 500 are connected (joined) to the end plates 400 (410, 420) by a plurality of (two in this embodiment) connecting members 500a arranged in the Z-axis direction. In this embodiment, the connecting members 500a are bolts, and are fastened by threading into nuts 450 (see FIG. 6) provided on the end plates 400. Here, of the pair of side plates 500, the side plate 500 on the positive side of the Y-axis direction is also referred to as side plate 501, and the side plate 500 on the negative side of the Y-axis direction is also referred to as side plate 502.

[0039] Similarly, a bottom plate 600 is disposed in the negative Z-axis direction of the plurality of power storage elements 200 and the plurality of intermediate spacers 300 (310 to 340). The bottom plate 600 is attached to the negative Z-axis direction ends of the pair of end plates 400 at both ends in the X-axis direction. Specifically, the bottom plate 600 has a shape in which both ends in the X-axis direction are bent toward the power storage element 200 side. Both ends of the bottom plate 600 are connected (joined) to the end plates 400 (410, 420) by a plurality (two in this embodiment) of connection members 600a arranged in the Y-axis direction. In this embodiment, the connection member 600a is a bolt and is fastened by screwing with a nut 450 (see FIG. 6) provided on the end plate 400. Thereby, the bottom plate 600, together with the pair of end plates 400, restrains the plurality of power storage elements 200 and the plurality of intermediate spacers 300 from the negative Z-axis direction side.

[0040] Further, a plurality of drawn portions 510 and 610 for increasing the strength are formed at the bent corners of the side plate 500 and the bottom plate 600, respectively. Each of the drawn portions 510 and 610 is formed by drawing so as to be convex toward the inside of the corner.

[0041] A pair of end spacers 800 are plate-shaped members arranged at positions sandwiching a pair of end plates 400 in the X-axis direction (predetermined direction). Specifically, the pair of end spacers 800 are arranged at positions sandwiching the connected end plates 400, side plates 500, and bottom plate 600 in the X-axis direction. Here, among the pair of end spacers 800, the end spacer 800 on the positive X-axis direction side is also referred to as end spacer 810, and the end spacer 800 on the negative X-axis direction side is also referred to as end spacer 820. Each end spacer 800 has a function of positioning each end plate 400, each side plate 500, bottom plate 600, a plurality of power storage elements 200, and a plurality of intermediate spacers 300 within the exterior body 110. The end spacer 800 is formed of, for example, a member having electrical insulation such as any resin material usable for the above-described exterior body 100, or a member having heat insulation such as a damping material. Details of the end spacer 800 will be described later.

[0042] [Description of Power Storage Element 2] Next, the configuration of the power storage element 200 will be described in detail. FIG. 4 is a perspective view showing the configuration of the power storage element 200 according to the embodiment. Specifically, FIG. 4 shows an enlarged view of the appearance of one power storage element 200 among the plurality of power storage elements 200 shown in FIG. 3. Since all of the plurality of power storage elements 200 have the same configuration, the configuration of one power storage element 200 will be described in detail below.

[0043] As shown in FIG. 4, the power storage element 200 includes a container 210, a pair (positive electrode side and negative electrode side) of electrode terminals 240, and an upper gasket 250. Further, inside the container 210, a lower gasket, an electrode body, a pair (positive electrode side and negative electrode side) of current collectors, an electrolytic solution (non-aqueous electrolyte), etc. are accommodated, but these are not shown in the figure. The type of the electrolytic solution is not particularly limited as long as it does not impair the performance of the power storage element 200, and various types can be selected.

[0044] In addition to the above components, the energy storage element 200 may have spacers arranged on the sides or below the electrode body, an insulating film that encases the electrode body, etc. Furthermore, an insulating film (shrink tube, etc.) that covers the outer surface of the container 210 may be arranged around the container 210. The material of the insulating film is not particularly limited as long as it can ensure the insulation required for the energy storage element 200, and examples of the material include insulating resins such as PC, PP, PE, PPS, PET, PBT, and ABS resin, epoxy resin, Kapton, Teflon (registered trademark), silicone, polyisoprene, and polyvinyl chloride.

[0045] The container 210 is a rectangular parallelepiped (square or box-shaped) case having a container body 220 with an opening formed therein and a lid 230 that closes the opening of the container body 220. The container body 220 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 210, and has an opening formed on the positive side of the Z axis. The lid 230 is a rectangular plate-like member that constitutes the lid of the container 210, and is disposed on the positive side of the Z axis, extending in the Y axis direction. The lid 230 is provided with a gas exhaust valve 231 that releases pressure inside the container 210 when the pressure inside the container 210 increases excessively, a liquid injection part (not shown) for injecting electrolyte into the container 210, and the like. The material of the container 210 (container body 220 and lid 230) is not particularly limited and can be, for example, a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, but resin can also be used.

[0046] The container 210 has a structure in which the electrode assembly and the like are housed inside the container body 220, and then the container body 220 and the lid 230 are joined by welding or the like, thereby sealing the interior. At the boundary between the container body 220 and the lid 230, the location joined by welding is called a welded portion 260 (see FIG. 9). The welded portion 260 is formed continuously around the entire periphery of the boundary between the container body 220 and the lid 230.

[0047] The container 210 has a pair of long sides 211 on both sides in the X-axis direction, a pair of short sides 212 on both sides in the Y-axis direction, and a bottom surface 213 on the negative Z-axis side. The long sides 211 are rectangular flat portions that form the long sides of the container 210. The long sides 211 are adjacent to the short sides 212 and the bottom surface 213. The short sides 212 are rectangular flat portions that form the short sides of the container 210, and are arranged opposite the side plate 500 in the Y-axis direction. The bottom surface 213 is a rectangular flat portion that forms the bottom surface of the container 210, and is arranged opposite the bottom plate 600 in the Z-axis direction and adjacent to the long sides 211 and the short sides 212.

[0048] The electrode terminals 240 are terminal members (positive and negative terminals) of the energy storage element 200 that are placed on the lid 230, and are electrically connected to the positive and negative electrode plates of the electrode body via current collectors. In other words, the electrode terminals 240 are metal members that draw out electricity stored in the electrode body to the external space of the energy storage element 200 and introduce electricity into the internal space of the energy storage element 200 to store electricity in the electrode body. The electrode terminals 240 are made of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

[0049] The electrode assembly is an electricity storage element (power generating element) formed by stacking 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 collector 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 collector 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 capable of absorbing and releasing lithium ions can be used. The separator can be a microporous resin sheet or nonwoven fabric. In this embodiment, the electrode assembly is formed by stacking electrode plates (positive electrode plates and negative electrode plates) in the X-axis direction. The electrode assembly may be of any shape, such as a wound electrode assembly formed by winding electrode plates (positive electrode plates and negative electrode plates), a stacked electrode assembly formed by stacking multiple flat electrode plates, or a bellows-shaped electrode assembly in which electrode plates are folded in a bellows shape.

[0050] The current collectors are conductive members (positive electrode current collector and negative electrode current collector) electrically connected to the electrode terminal 240 and the electrode body. The positive electrode current collector is made of aluminum or an aluminum alloy, etc., like the positive electrode substrate layer of the positive electrode plate, and the negative electrode current collector is made of copper or a copper alloy, etc., like the negative electrode substrate layer of the negative electrode plate.

[0051] The upper gasket 250 is disposed between the lid 230 and the electrode terminal 240, and is a gasket that insulates and seals between the lid 230 and the electrode terminal 240. The lower gasket is disposed between the lid 230 and the current collector, and is a gasket that insulates and seals between the lid 230 and the current collector. The upper gasket 250 and the lower gasket may be made of any material that has electrical insulation properties.

[0052] [3 End plate explanation] Next, the configuration of end plate 400 (410, 420) will be described in detail. Note that end plate 410 and end plate 420 have the same configuration. For this reason, the following description will focus on the configuration of end plate 410, and the configuration of end plate 420 will be assumed to be similar to that of end plate 410, and a detailed description thereof will be omitted. Specifically, end plate 420 has the same configuration as end plate 410 rotated 180 degrees around the Z axis.

[0053] 5 and 6 are exploded perspective views showing the configuration of end plate 410 according to the embodiment. Specifically, Fig. 5 is an exploded perspective view of end plate 410 as seen from the positive direction of the X axis, and Fig. 6 is an exploded perspective view of end plate 410 as seen from the negative direction of the X axis.

[0054] As shown in FIGS. 5 and 6, the end plate 410 has a first plate 430 and a second plate 440, which are joined together by welding, for example.

[0055] The first plate 430 is a corrugated sheet metal laminated on the main surface of the second plate 440 in the +X-axis direction. Specifically, the first plate 430 has a plurality of recesses 431 and a plurality of protrusions 432, and each recess 431 and each protrusion 432 are repeatedly arranged in the Z-axis direction. When the first plate 430 is viewed as a whole, each recess 431 is a portion recessed in the -X-axis direction, and each protrusion 432 is a portion protruding in the +X-axis direction. In the present embodiment, four recesses 431 are provided and three protrusions 432 are provided, but the number of the recesses 431 and the protrusions 432 provided may be any number.

[0056] The bottom wall 433 of each recess 431 is a flat plate portion parallel to the YZ plane and arranged at the same position in the X-axis direction. Also, the top wall 434 of each protrusion 432 is a flat plate portion parallel to the YZ plane and arranged at the same position in the X-axis direction. In each protrusion 432, the upper side wall 435 is a wall connecting the top wall 434 of the protrusion 432 and the bottom wall 433 of the recess 431 directly above the protrusion 432. In each protrusion 432, the lower side wall 436 is a wall connecting the top wall 434 of the protrusion 432 and the bottom wall 433 of the recess 431 directly below the protrusion 432. That is, the upper side wall 435 of each protrusion 432 is also the lower side wall of the recess directly above it, and the lower side wall 436 of each protrusion 432 is the upper side wall of the recess directly below it. Due to such a shape, a space is formed inside each protrusion 432.

[0057] Here, among the plurality of protrusions 432, the one located at the uppermost position is referred to as the protrusion 432a, the one located in the middle position is referred to as the protrusion 432b, and the one located at the lowermost position is referred to as the protrusion 432c. The protrusion 432a is formed such that both end portions in the Y-axis direction are wider than the central portion. Specifically, in a plan view (viewed in the X-axis direction), the lower edge of the top wall 434a of the protrusion 432a is formed in a substantially straight line shape, while the upper edge of the top wall 434a is formed in a stepped shape such that the central portion in the Y-axis direction is at a lower position and both end portions are at a higher position. For this reason, the upper side wall 435 of the protrusion 432a is formed in a stepped shape, and the lower side wall 436 is formed in a straight line shape.

[0058] On the one hand, the convex portions 432b and 432c are each formed with a generally uniform width over the entire length in the Y-axis direction. For this reason, the upper side walls 435 and the lower side walls 436 of the convex portions 432b and 432c are each formed linearly.

[0059] A pair of through holes 437 are provided in each of the top walls 434a, 434b, and 434c. Specifically, each through hole 437 is disposed at both ends in the Y-axis direction of each of the top walls 434a, 434b, and 434c and penetrates in the X-axis direction. A pair of nuts 450 are fixed to the surfaces of each of the top walls 434a, 434b, and 434c in the minus X-axis direction. Each nut 450 is fixed to each of the top walls 434a, 434b, and 434c by welding or the like so that the screw holes communicate with the respective through holes 437.

[0060] Here, a side plate 500 is fastened to the through holes 437 and the nuts 450 of the top walls 434a and 434b via a connecting member 500a. A bottom plate 600 is fastened to the through holes 437 and the nuts 450 of the top wall 434c via a connecting member 600a. In this way, the nut 450 and the connecting member 500a are an example of a fastening portion that fastens the end plate 410 and the side plate 500. Similarly, the nut 450 and the connecting member 600a are an example of a fastening portion that fastens the end plate 410 and the bottom plate 600. That is, the nut 450, which is a part of the fastening portion, is disposed within the space inside each convex portion 432. In the present embodiment, the case where the fastening portion is a screw type is exemplified, but a rivet type fastening portion may also be used. Even if it is a rivet type fastening portion, as long as one end portion of the rivet is disposed within the space inside each convex portion 432.

[0061] On the upper edge of the recess 431 located at the uppermost position among the plurality of recesses 431, a first protruding portion 438 protruding in the plus X-axis direction is provided. The first protruding portion 438 extends continuously in the Y-axis direction over the entire length of the upper edge, which is one edge of the first plate 430.

[0062] In addition, in the present embodiment, the case where the lower end portion of the lowermost recess 431 does not protrude is illustrated, but the lower end portion may protrude in the positive X-axis direction.

[0063] The second plate 440 is disposed between the first plate 430 and the plurality of power storage elements 200, and is a generally flat sheet metal that overlaps the first plate 430. Specifically, the second plate 440 is disposed between the intermediate spacer 340 in the positive X-axis direction and the first plate 430, and is directly overlapped with them.

[0064] The second plate 440 has a flat plate portion 441 and a pair of second protrusions 442. The flat plate portion 441 is a rectangular and flat portion in plan view, and is in contact with the bottom walls 433 of all the recesses 431 of the first plate 430. That is, the flat plate portion 441 is in surface contact with the bottom walls 433 of all the recesses 431. Further, the flat plate portion 441 is disposed at an interval from the top walls 434a, 434b, and 434c of all the protrusions 432, and covers the space inside each protrusion 432 from the negative X-axis direction. The portion of the flat plate portion 441 that covers the space inside each protrusion 432 is referred to as a wall portion 445. In FIG. 5, the region surrounded by the broken line is the wall portion 445. As shown in FIG. 5, the wall portions 445 are provided on the flat plate portion 441 in a number corresponding to the number of installed protrusions 432. It can also be said that the plurality of wall portions 445 are formed in a flat plate shape as a whole.

[0065] The pair of second protrusions 442 are portions that protrude in the positive X-axis direction from both ends in the Y-axis direction of the flat plate portion 441. Each second protrusion 442 extends along the Z-axis direction. In this way, the second protrusion 442 protrudes in the same direction as the first protrusion 438 and extends in a direction intersecting the predetermined direction (X-axis direction).

[0066] Specifically, each second protruding portion 442 extends in the Z-axis direction from the upper end portion of the flat plate portion 441 to a position corresponding to the side plate 500. A plurality of notch-shaped escape portions 443 for allowing the throttle portion 510 provided on the side plate 500 to escape are formed at the tip end portions of the second protruding portions 442. Since each throttle portion 510 of each side plate 500 is accommodated in each escape portion 443, it is difficult for each throttle portion 510 to interfere with the second protruding portion 442.

[0067] A plurality of throttle portions 444 for enhancing strength are provided at the corner portions formed by each second protruding portion 442 and the flat plate portion 441. Each throttle portion 444 is formed by throttling so as to protrude inwardly of the corner portion.

[0068] In this way, in the end plate 410, since the first plate 430 is provided with a convex portion 432 having a space inside, for example, when the convex portion 432 receives an external impact, the convex portion 432 deforms while crushing the space and absorbs the impact.

[0069] Furthermore, in the end plate 410, since the second plate 440 is provided with a wall portion 445 that covers the space between the convex portion 432 and the plurality of power storage elements 200, even if the convex portion 432 collapses, the wall portion 445 serves as a barrier and it is possible to suppress the convex portion 432 from reaching the power storage element 200. Thereby, when receiving an external impact, it is possible to suppress damage to the power storage element 200.

[0070] In particular, in the present embodiment, since a part of the fastening portion (connecting members 500a and 600a) is accommodated in the space of the convex portion 432, for example, even if the fastening portion receives an external impact and is pressed toward the power storage element 200, the wall portion 445 serves as a barrier and it is possible to suppress the fastening portion from reaching the power storage element 200. Thereby, when receiving an external impact, it is possible to suppress damage to the power storage element 200 caused by the fastening portion.

[0071] Furthermore, in the present embodiment, since the first plate 430 has a plurality of convex portions 432, a concave portion 431 is formed between a pair of adjacent convex portions 432. That is, since the first plate 430 has a concavo-convex structure, the rigidity of the first plate 430 can be further increased. Thereby, it is possible to increase the rigidity of the end plate 410 itself.

[0072] In addition, the flat plate portion 441 of the second plate 440 has a plurality of wall portions 445 that are flat as a whole and are in contact with the plurality of concave portions 431 of the first plate 430. For example, when the first plate 430 receives an external impact, stress is transmitted from the plurality of concave portions 431 to the flat plate portion 441. However, since the flat plate portion 441 is in contact with the plurality of concave portions 431, the stress can be dispersed. Therefore, it is possible to suppress a large stress from being applied to the power storage element 200, and it is possible to further suppress damage to the power storage element 200.

[0073] FIG. 7 is a plan view showing the second plate 440 according to the embodiment. In FIG. 7, the outer shape of the first plate 430 is indicated by a two-dot chain line. Here, as described above, the second plate 440 is generally formed in a flat plate shape, while the first plate 430 is formed in a corrugated shape. That is, since the second plate 440 has a smaller surface area than the first plate 430, the second plate 440 can be made smaller than the first plate 430. On the other hand, as shown in FIG. 7, the second plate 440 has a larger projected area than the first plate 430 in the X-axis direction view. For this reason, the impact received by the first plate 430 can be dispersed over a wider range.

[0074] [Description of the 4 End Spacers] Next, the configuration of the end spacers 800 (810, 820) will be described in detail. Note that the end spacer 810 and the end spacer 820 have the same configuration. For this reason, hereinafter, the configuration of the end spacer 810 will be mainly described, and the configuration of the end spacer 820 shall conform to that of the end spacer 810, and detailed description thereof will be omitted. Specifically, the end spacer 820 has the same configuration as when the end spacer 810 is rotated 180 degrees around the Z axis.

[0075] FIG. 8 is a perspective view showing the configuration of the end spacer 810 according to the embodiment. Specifically, FIG. 8 is a perspective view of the end spacer 810 viewed from the positive X-axis direction. The end spacer 810 is disposed along a part of the outer peripheral edge of the end plate 410 with the central portion of the end plate 410 overlapping in the X-axis direction exposed. Specifically, as shown in FIG. 8, the end spacer 810 is a member that is substantially U-shaped in plan view and is flat, and is disposed along the outer peripheral edge of the end plate 410 except for the upper part. The end spacer 810 has a lower edge portion 811 and a pair of side edge portions 812. The lower edge portion 811 is a rectangular flat plate-shaped portion that is long in the Y-axis direction. The lower edge portion 811 is disposed at the corner formed by the wall surface forming the short side surface and the wall surface forming the bottom surface of the exterior body main body 110. A pair of through holes 813 for accommodating the heads 600b of the respective connecting members 600a are formed in the lower edge portion 811. The pair of through holes 813 are arranged at a predetermined interval in the Y-axis direction.

[0076] Each side edge portion 812 is a rectangular flat plate-shaped portion that is long in the Z-axis direction. Each side edge portion 812 continuously extends upward from both ends in the Y-axis direction of the lower edge portion 811. Each side edge portion 812 is disposed at the corner formed by the wall surface forming the long side surface and the wall surface forming the short side surface of the exterior body main body 110. A pair of through holes 814 for accommodating the heads 500b of the respective connecting members 500a are formed in each side edge portion 812. The pair of through holes 814 are arranged at a predetermined interval in the Z-axis direction.

[0077] The central portion of the end plate 410 is exposed by the area surrounded by the lower edge portion 811 and the pair of side edges 812. The width of this area (the distance between the pair of side edges 812) is at least half the width (length in the Y-axis direction) of the end spacer 810, and the height of this area is at least half the height (length in the Z-axis direction) of the end spacer 810. This results in a large portion of the central portion of the end plate 410 being exposed, making it easier to tolerate deformation of this central portion.

[0078] [5 Positional relationship between end plates, end spacers and surrounding components] Next, the positional relationship between the end plate 410, the end spacer 810, and the surrounding members will be described. Fig. 9 is a cross-sectional view showing the positional relationship between the end plate 410, the end spacer 810, and the surrounding members according to the embodiment. Fig. 9 illustrates the structure around the upper part of the end plate 410, etc.

[0079] 9, the main surface of the end spacer 810 in the positive X-axis direction abuts against the inner surface of the exterior body main body 110. This prevents the contents (including the multiple energy storage elements 200, intermediate spacer 300, end plate 400, side plate 500, and bottom plate 600) including the end spacer 810 from moving in the X-axis direction by the exterior body main body 110. This makes it possible to make the contents less likely to be displaced even if the energy storage device 10 vibrates, thereby reducing impact on the contents. It is preferable that the contents are press-fitted into the exterior body main body 110, as this increases the effect of suppressing displacement of the contents.

[0080] Also, the end spacer 810 is formed with a uniform wall thickness as a whole. The wall thickness of the end spacer 810 is thicker than the wall thickness (axial length) of the head 500b of the connecting member 500a. As a result, the head 500b of the connecting member 500a does not protrude from the end spacer 810. For this reason, even if the exterior body main body 110 is impacted from the outside, the end spacer 810 receives the impact, and the impact is less likely to be directly transmitted to the head 500b of the connecting member 500a. Therefore, it is possible to suppress damage to the connecting member 500a. This is the same for the head 600b of the connecting member 600a.

[0081] In FIG. 9, the boundary portion between the container main body 220 and the lid body 230 of the power storage element 200 is the welding portion 260. At least a part of the welding portion 260 is accommodated within the thickness (length in the Z-axis direction) of the first protrusion 438 of the first plate 430. For this reason, the first protrusion 438 of the first plate 430 overlaps the welding portion 260 when viewed in the X-axis direction. Here, the welding portion 260 is more fragile than other parts of the container 210, but since the first protrusion 438 overlaps the welding portion 260 when viewed in the X-axis direction, even if the welding portion 260 tries to bulge due to the expansion of the container 210, the first protrusion 438 can suppress the bulge of the welding portion 260. Even if a crack occurs in the welding portion 260, since the first protrusion 438 overlaps the welding portion 260 when viewed in the X-axis direction, it is possible to suppress the displacement between the container main body 220 and the lid portion 230 starting from the crack. In particular, in the present embodiment, since the intermediate spacer 340 directly overlaps the welding portion 260 when viewed in the X-axis direction, the displacement between the container main body 220 and the lid portion 230 starting from the aforementioned crack can be more reliably suppressed.

[0082] [Description of Effects] As described above, the power storage device 10 according to the embodiment of the present invention includes a plurality of power storage elements 200 having a container main body 220 and a lid body 230 that closes the container main body 220 and is welded to the container main body 220, a pair of end plates 400 that sandwich the plurality of power storage elements 200 arranged in a predetermined direction in the predetermined direction, and a connecting portion that extends along the predetermined direction and is connected to the pair of end plates. At least one of the pair of end plates has a first protruding portion 438 that protrudes toward the side opposite to the power storage element 200 at a portion that overlaps with the welding portion 260 between the container main body 220 and the lid body 230 when viewed in a predetermined direction (X-axis direction).

[0083] According to this, since the first protruding portion 438 is provided on at least one of the end plates 400, the rigidity of the end plate 400 itself can be increased. As a result, the expansion of the power storage element 200 can be suppressed by the end plate 400, and damage to the power storage element 200 caused by the expansion can be suppressed. In particular, in the power storage element 200, the welding portion 260 between the container main body 220 and the lid body 230 is more fragile than other portions, so when the power storage element 200 expands, the welding portion 260 is likely to be damaged. For this reason, in at least one of the end plates 400, the portion overlapping the welding portion 260 of the power storage element 200 is the first protruding portion 438. Thus, even if the welding portion 260 of the power storage element 200 tries to bulge, the expansion of the welding portion 260 can be suppressed by the first protruding portion 438 of the end plate 400. Therefore, damage to the power storage element 200 can be suppressed.

[0084] Here, when the first protruding portion 438 protrudes toward the power storage element 200, for example, if the end plate 400 is deformed due to an external impact, the first protruding portion 438 may hit the welding portion 260 of the power storage element 200. As described above, the welding portion 260 is a vulnerable part, so if the first protruding portion 438 hits it, it is more likely to be damaged compared to other parts. In the present embodiment, since the first protruding portion 438 protrudes toward the side opposite to the power storage element 200, even if the end plate 400 is deformed, the first protruding portion 438 is less likely to hit the welding portion 260 of the power storage element 200. Therefore, even when the end plate 400 is deformed, damage to the power storage element 200 can be suppressed.

[0085] Also, at least one of the end plates 400 has a first plate 430 having a first protruding portion 438, and a second plate 440 disposed between the first plate 430 and the plurality of power storage elements 200 and overlapping the first plate 430.

[0086] According to this, since it is the end plate 400 where the first plate 430 and the second plate 440 overlap, the rigidity of the end plate 400 itself can be increased. Therefore, the expansion of the power storage element 200 can be more reliably suppressed, and damage to the power storage element 200 can be more suppressed.

[0087] Further, the first plate 430 has a plurality of concave portions 431 recessed in a direction opposite to the first protruding portion 438, and at least one convex portion 432 protruding in the same direction as the first protruding portion 438 between adjacent concave portions 431. The second plate 440 has a flat plate portion 441 that abuts against all of the plurality of concave portions 431.

[0088] According to this, the first plate 430 has a concave-convex structure consisting of a plurality of concave portions 431 and at least one convex portion 432, which can further increase the rigidity of the first plate 430. This can increase the rigidity of the end plate 400 itself. Meanwhile, the second plate 440 has a flat plate portion 441 that abuts against all of the plurality of concave portions 431 of the first plate 430. For example, when the first plate 430 receives an external impact, stress is transmitted from each of the concave portions 431 to the flat plate portion 441. However, since the flat plate portion 441 abuts against all of the plurality of concave portions 431, the stress can be dispersed. Therefore, it is possible to prevent large stress from being applied to the energy storage element 200. As a result, damage to the energy storage element 200 can be further suppressed.

[0089] The second plate 440 also has a second protruding portion 442 that protrudes in the same direction as the first protruding portion 438 and extends in a direction intersecting the predetermined direction.

[0090] According to this, since the second protrusion 442 is provided on the second plate 440, the rigidity of the second plate 440 itself can be increased. This increases the rigidity of the end plate 400 itself. Therefore, expansion of the energy storage elements 200 can be more reliably suppressed, and damage to the energy storage elements 200 can be further suppressed.

[0091] The first protrusion 438 extends continuously over the entire length of one edge of the first plate 430 .

[0092] According to this, the first protrusion 438 extends continuously over the entire length of one edge of the first plate 430, thereby increasing the rigidity of the first plate 430 itself. This increases the rigidity of the end plate 400 itself. Therefore, expansion of the energy storage elements 200 can be more reliably suppressed, and damage to the energy storage elements 200 can be further suppressed.

[0093] Further, the power storage device 10 includes a plurality of power storage elements 200 arranged in a predetermined direction (X-axis direction), a pair of end plates 400 that sandwich the plurality of power storage elements 200 in the predetermined direction, a connecting portion (side plate 500 and bottom plate 600) that extends along the predetermined direction and is connected to the pair of end plates 400, a pair of end spacers 800 disposed at positions that sandwich the pair of end plates 400 in the predetermined direction, and an exterior body 100 that houses the plurality of power storage elements 200, the pair of end plates 400, the connecting portion, and the pair of end spacers 800. The end spacer 800 is disposed along a part of the outer peripheral edge of the end plate 400 with the central portion of the end plate 400 that overlaps in the predetermined direction exposed.

[0094] According to this, since the end spacer 800 exposes the central portion of the end plate 400, it is possible to allow deformation of the end plate 400 caused by expansion of the central portion of the power storage element 200. Therefore, a mechanical load on the expanded power storage element 200 can be suppressed.

[0095] Further, since the end spacer 800 is disposed along a part of the outer peripheral edge of the end plate 400, the end spacer 800 is disposed to face at least one side of the inner edge of the exterior body 100 in a view in the predetermined direction. The inner edge of the exterior body 100 in a view in the predetermined direction is a corner portion of two wall surfaces of the exterior body 100, and thus has high strength, for example, as compared with the central portion of the wall surface. That is, it can be said that the inner edge of the exterior body 100 is a portion that is difficult to deform. Since the end spacer is received by at least one side of this inner edge, it is possible to stably restrict the movement of the contents inside the exterior body 100.

[0096] Further, since the end spacer 800 is received by the relatively high-strength inner edge in the exterior body 100, even if the contents inside the exterior body 100 move in the predetermined direction due to vibration, it is possible to make the exterior body 100 less likely to be damaged.

[0097] Further, the exterior body 100 includes an exterior body main body 110 having an opening formed therein upward, and an exterior body lid 120 covering the opening of the exterior body main body 110. The end spacer 800 is disposed along the outer peripheral edges of the end plate 400 except for the upper portion of the outer peripheral edge thereof.

[0098] Here, in the exterior body 100, the portion corresponding to the joint portion between the exterior body main body 110 and the exterior body lid 120 is a weaker portion than other portions of the exterior body 100. In the end spacer 800 of the present embodiment, since it is disposed along the outer peripheral edges of the end plate 400 except for the upper portion of the outer peripheral edge thereof, even if the central portion and the upper portion of the power storage element 200 expand, the deformation is less likely to be transmitted to the joint portion between the exterior body main body 110 and the exterior body lid 120. Therefore, damage to the joint portion caused by the expansion of the power storage element 200 can be suppressed.

[0099] Further, the power storage device 10 has bolts (connection members 500a and 600a) for fastening the connecting portions to the end plate 400. Through holes 813 and 814 for accommodating the bolt heads 500b and 600b are formed in the end spacer 800. The wall thickness of the end spacer 800 is thicker than the wall thickness of the bolt heads 500b and 600b.

[0100] According to this, since the wall thickness of the end spacer 800 is thicker than the wall thickness of the bolt heads 500b and 600b, the bolt heads 500b and 600b do not protrude from the end spacer 800. For this reason, even if the exterior body 100 receives an impact from the outside, the end spacer 800 receives the impact, and the impact is less likely to be directly transmitted to the bolt heads 500b and 600b. Therefore, damage to the bolts can be suppressed.

[0101] [Description of Modification Example 7] As described above, the power storage device 10 according to the present embodiment has been explained. However, the present invention is not limited to the above embodiment. The embodiments disclosed this time are illustrative in all respects and not restrictive, and the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims. In the following description, the same reference numerals may be given to the same parts as those in the above embodiment, and the description thereof may be omitted.

[0102] For example, in the above embodiment, the case where the end spacer 800 is not fixed to the end plate 400 has been exemplified. However, the end spacer 800 may be fixed to the end plate 400. Specifically, a structure may be adopted in which a collar is embedded in the peripheral portions of the through holes 813 and 814 of the end spacer 800, and the heads 500b and 600b of the connection members 500a and 600a bite into the respective collars. In this case, the collar and the connection members 500a and 600a serve as a spacer fixing portion fixed to the end plate 400.

[0103] According to this, since the end spacer 800 is provided with a spacer fixing portion fixed to the end plate 400, the integrality between the end plate 400 and the end spacer 800 can be enhanced by the spacer fixing portion. Therefore, even if the power storage device 10 is subjected to vibration, the relative displacement between the end plate 400 and the end spacer 800 can be suppressed. Thereby, damage to each member in the power storage device 10 caused by the relative displacement can be suppressed.

[0104] Note that the spacer fixing portion is not limited to the above-described form as long as it is fixed to the end plate 400. For example, an engagement structure that engages with the end plate 400 may be used as the spacer fixing portion, or a joint portion welded or adhered to the end plate 400 may be used as the spacer fixing portion.

[0105] Further, the spacer fixing portion may be fixed to the bus bar holder 900. FIG. 10 is a plan view showing an end spacer 810A according to a modification. In FIG. 10, a case where the spacer fixing portion 850a has a snap fit structure is illustrated.

[0106] As shown in FIG. 10, on each side edge portion 812a of the end spacer 810A, a pair of claw portions 851 forming a spacer fixing portion 850a at the upper end are provided. The pair of claw portions 851 are elastically deformable portions and are arranged at intervals from each other. At the tip portions of the pair of claw portions 851, protrusions 852 protruding outward are formed.

[0107] The bus bar holder 900 has a portion that overlaps the upper end portion of each side edge portion 812a of the end spacer 810A. In the bus bar holder 900, engagement hole portions 910 are formed at portions facing the pair of claw portions 851 of each side edge portion 812a. When the pair of claw portions 851 are inserted into the engagement hole portions 910 and the protrusions 852 are caught, the pair of claw portions 851 are locked. Thereby, the spacer fixing portion 850a is fixed to the bus bar holder 900.

[0108] Thus, since the end spacer 810A is provided with the spacer fixing portion 850a that is fixed to the bus bar holder 900, the integrality between the bus bar holder 900 and the end spacer 810A can be enhanced by the spacer fixing portion 850a. Therefore, even if the power storage device 10 receives vibration, relative displacement between the bus bar holder 900 and the end spacer 810A can be suppressed.

[0109] Note that the spacer fixing portion fixed to the bus bar holder 900 is not limited to the above-described form as long as it is fixed to the bus bar holder 900. For example, a joint portion welded or adhered to the bus bar holder 900 may be used as the spacer fixing portion. Further, both the spacer fixing portion for the bus bar holder and the spacer fixing portion for the end plate may be provided on one end spacer.

[0110] Alternatively, the end spacer and the inner surface of the exterior body may be engaged with each other. Fig. 11 is a partial cross-sectional view showing an engagement structure between an end spacer 810B and an exterior body 110B according to a modified example.

[0111] 11, multiple first ribs 111 are arranged at predetermined intervals on the inner surface of exterior body main body 110B facing end spacer 810B. The multiple first ribs 111 are portions that protrude in the X-axis direction and are arranged at predetermined intervals in the Y-axis direction, for example. Each first rib 111 extends along the Z-axis direction.

[0112] A plurality of second ribs 881 are provided on a main surface of the end spacer 810B facing the inner surface of the exterior body main body 110B, the second ribs 881 being arranged between the plurality of first ribs 111. The plurality of second ribs 881 are portions that protrude in the X-axis direction and are arranged, for example, at predetermined intervals in the Y-axis direction. Each second rib 881 extends along the Z-axis direction. Because each second rib 881 is arranged between the plurality of first ribs 111 of the exterior body main body 110B, the first ribs 111 and the second ribs 881 interfere with each other when the energy storage device 10 vibrates. This interference can suppress displacement of the end spacer 810B within the exterior body main body 110B. This can suppress damage to components within the energy storage device 10 caused by displacement of the end spacer 810B. Note that the number of second ribs 881 may be one. Furthermore, if the second rib 881 is fitted between the plurality of first ribs 111, the effect of suppressing displacement of the end spacer 810B can be further enhanced.

[0113] In the above embodiment, the end spacer 800 has a generally U-shape in plan view. However, the end spacer may have any shape as long as it is disposed along a part of the outer periphery of the end plate 400 while leaving the central portion of the end plate exposed.

[0114] FIG. 12 is a perspective view showing the configuration of an end spacer 810C according to a modified example. As shown in FIG. 12, the end spacer 810C has a beam portion 860 that connects a pair of side edges 812 and extends continuously from the upper portions of each side edge 812. Specifically, the beam portion 860 is provided at a low position and spaced apart from the upper ends of each side edge 812. Even in this case, the area surrounded by the pair of side edges 812, the beam portion 860, and the lower edge 811 exposes the center of the end plate 410. Note that other shapes include an end spacer consisting of only a pair of side edges 812. In this case, the pair of side edges 812 are separated from each other.

[0115] Although the above embodiment illustrates the two-piece end plate 400, a single-piece end plate may be used. In this case, the end plate has only one of the first plate and the second plate, and the first protrusion may be provided on one of the plates.

[0116] In the above embodiment, the end plate 400 is exemplified as being made up of separate members, the first plate 430 and the second plate 440. However, the end plate may be made up of a single piece of sheet metal that is bent to form a continuous first and second plate.

[0117] Furthermore, in the above embodiment, the case where intermediate spacer 340 is interposed between end plate 400 and energy storage element 200 has been illustrated, but the end plate and the energy storage element may be directly overlapped.

[0118] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention. [Industrial Applicability]

[0119] The present invention can be applied to an electricity storage device or the like that includes an electricity storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0120] 10 Energy storage device 100 Exterior body 110, 100B Exterior body main body 111 First rib 120 Exterior body cover 121 External terminal 200 Energy storage element 210 Container 211 Long side surface 212 Short side surface 213 Bottom surface 220 Container main body 230 Cover 231 Gas discharge valve 240 Electrode terminal 250 Upper gasket 260 Weld part 300, 310, 320, 330, 340 Intermediate spacer 400, 410, 420 End plate 430 First plate 431 Recess 432, 432a, 432b, 432c Protrusion 433 Bottom wall 434, 434a, 434b, 434c Top wall 435 Upper side wall 436 Lower side wall 437, 813, 814 Through hole 438 First protrusion 440 Second plate 441 Flat plate part 442 Second protrusion 443 Relief part 444, 510, 610 Throttle part 445 Wall part 450 Nut 500, 501, 502 Side plate (connection part) 500a, 600a Connection member (bolt) 500b, 600b Head 600 Bottom plate (connection part) 700 Bus bar 800, 810, 810A, 810B, 810C, 820 End spacer Lower edge part 811 Side edge parts 812, 812a Spacer fixing part 850a Claw part 851 Projection 852 Beam part 860 Second rib 881 Bus bar holder 900 Engagement hole part 910

Claims

1. A plurality of power storage elements having a container body and a lid that closes the container body and is welded to the container body, A pair of end plates that sandwich the plurality of power storage elements arranged in a predetermined direction in the predetermined direction, A connecting portion that extends along the predetermined direction and is connected to the pair of end plates, At least one of the pair of end plates has a first protruding portion in which a portion overlapping the welded portion of the container body and the lid as viewed in the predetermined direction protrudes toward the side opposite to the power storage element, The at least one end plate, A first plate made of metal having the first protruding portion, A second plate made of metal disposed between the first plate and the plurality of power storage elements and overlapping the first plate, The second plate overlaps the welded portion as viewed in the predetermined direction, A gap is formed in a portion overlapping the welded portion as viewed in the predetermined direction between the first plate and the second plate Power storage device.

2. The first plate, A plurality of recesses recessed in a direction opposite to the first protruding portion, At least one convex portion that protrudes in the same direction as the first protruding portion and is between adjacent recesses, The second plate has a flat plate portion that abuts against all of the plurality of recesses The power storage device according to claim 1.

3. The second plate has a second protruding portion that protrudes in the same direction as the first protruding portion and extends in a direction intersecting the predetermined direction The power storage device according to claim 1 or 2.

4. The first protruding portion extends continuously over the entire length of one edge of the first plate The power storage device according to any one of claims 1 to 3.

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