Power storage device

Abstract

To provide a power storage device capable of suppressing damage of a power storage element.SOLUTION: A power storage device 10 comprises: a plurality of power storage elements 200 arrayed in a first direction (X-axis direction); a pair of end plates 400 holding the plurality of power storage elements 200 therebetween in the first direction; and a pair of coupling members (side plates 500) extending in the first direction, the pair of coupling members being coupled to the pair of end plates 400 while holding the plurality of power storage elements 200 therebetween in a second direction (Y-axis direction) which crosses the first direction. At least one of the pair of end plates 400 includes a first projection 441 extending so as to connect coupling positions of the pair of coupling members with each other and a second projection 442 extending in a direction crossing a predetermined direction in which the first projection 441 extends.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, there has been known an electric storage device in which a plurality of electric storage elements, such as lithium ion batteries, are housed in a pair of divided exterior bodies, and the connecting surfaces of the pair of exterior bodies are heat-welded together. In such an electric storage device, a pair of flat end plates arranged at positions sandwiching the plurality of electric storage elements are also housed in the exterior body (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-79599 Summary of the Invention [Problem to be solved by the invention]

[0004] Energy storage elements have the property of gradually expanding as they are charged and discharged. As a result, as the expansion of the energy storage elements progresses, the end plates may also deform. If the end plates deform, the expansion of the energy storage elements cannot be suppressed, which could damage the energy storage elements or the exterior housing, potentially reducing the reliability of the energy storage device.

[0005] The present invention aims to suppress the deterioration of the reliability of the electricity storage device by suppressing deformation of the end plates. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a storage device according to one embodiment of the present invention comprises a plurality of storage elements arranged in a first direction, a pair of end plates sandwiching the plurality of storage elements in the first direction, and a pair of connecting members extending along the first direction and connected to the pair of end plates in a state sandwiching the plurality of storage elements in a second direction intersecting the first direction, wherein at least one of the pair of end plates has a first convex portion extending to connect the respective connecting positions of the pair of connecting members, and a second convex portion extending in a direction intersecting the predetermined direction in which the first convex portion extends. [Effects of the Invention]

[0007] According to the electricity storage device of the present invention, it is possible to suppress a decrease in reliability. [Brief explanation of the drawings]

[0008] [Figure 1] 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 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] 10 is a plan view of the end plate according to the embodiment, as viewed from the positive direction of the X-axis. FIG. [Figure 8] FIG. 10 is a plan view showing an end plate according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] A storage device according to one embodiment of the present invention comprises a plurality of storage elements arranged in a first direction, a pair of end plates sandwiching the plurality of storage elements in the first direction, and a pair of connecting members extending along the first direction and connected to the pair of end plates in a state sandwiching the plurality of storage elements in a second direction intersecting the first direction, wherein at least one of the pair of end plates has a first convex portion extending to connect the respective connecting positions of the pair of connecting members, and a second convex portion extending in a direction intersecting the predetermined direction in which the first convex portion extends.

[0010] According to this, at least one end plate is provided with a first convex portion extending to connect the connection positions of the pair of connecting members and a second convex portion extending in a direction intersecting the predetermined direction in which the first convex portion extends. Therefore, even if bending forces act on the end plate in various directions, the first convex portion and the second convex portion can suppress bending of the end plate. In other words, the rigidity of the end plate itself is increased, thereby suppressing deformation of the end plate. This suppresses expansion of the energy storage elements and damage to the exterior body, and suppresses a decrease in the reliability of the energy storage device.

[0011] The end plate may have a non-placement area in a third direction intersecting the first direction and the second direction in which the pair of connecting members are not placed, and the second convex portion may be placed in the non-placement area.

[0012] Here, the non-placement areas of the end plate in the third direction where no connecting members are arranged are susceptible to bending forces originating from the connecting positions because no connecting members are arranged. In this aspect, the second convex portions are provided in the non-placement areas, so the non-placement areas of the end plate where no connecting members are arranged can be reinforced by the second convex portions, thereby suppressing bending of those areas. In other words, deformation of the easily deformed parts of the end plate can be suppressed, and deformation of the end plate can be more reliably suppressed. This further suppresses expansion of the energy storage elements and damage to the exterior body, and more reliably suppresses a decrease in the reliability of the energy storage device.

[0013] The second protrusion may extend from the first protrusion toward an edge of the end plate.

[0014] In this configuration, the second protrusions extend from the first protrusions toward the edges of the end plates, thereby increasing the rigidity of the end plates up to the vicinity of the edges. This increases the rigidity of the end plates themselves, thereby more reliably suppressing deformation of the end plates. This further reduces expansion of the energy storage elements and damage to the exterior housing, and more reliably suppresses a decrease in the reliability of the energy storage device.

[0015] The end plate may be formed by stacking a plurality of plates.

[0016] In this case, since the end plates are formed by stacking multiple plates, it is possible to further increase the rigidity of the end plates themselves. This makes it possible to more reliably suppress deformation of the end plates. Therefore, it is possible to more reliably suppress expansion of the energy storage elements and damage to the exterior body, and more reliably suppress deterioration in the reliability of the energy storage device.

[0017] (Embodiment) 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.

[0018] In the following description and drawings, the arrangement direction of multiple energy storage elements, the opposing direction of the long side surfaces of the energy storage element containers, the alignment direction of the energy storage elements and intermediate spacers, and the alignment direction of a pair of end plates are defined as the X-axis direction. The alignment direction of a pair of electrode terminals (positive and negative) of one energy storage element, the opposing direction of the short side surfaces of the energy storage element container, or the alignment direction of a pair of side plates is defined as the Y-axis direction. The alignment direction of the exterior body and exterior body lid of the energy storage device, the alignment direction of the energy storage element container body and container lid, the alignment direction of the energy storage elements and bus bars, or the up-down direction is defined as the Z-axis direction. The X-axis direction is an example of a first direction, the Y-axis direction is an example of a second direction, and the Z-axis direction is an example of a third direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect each other (orthogonal in this embodiment). Note that depending on the usage mode, the Z-axis direction may not be the up-down direction; however, for convenience of explanation, the following description will be made assuming the Z-axis direction to be the up-down direction.

[0019] 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. When simply referring to the X-axis direction, it refers to both or either of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis and Z-axis directions. Expressions indicating relative directions or attitudes, such as parallel and orthogonal, also include cases where the directions or attitudes are not strictly those of the same kind. For example, when two directions are parallel, it does not only mean that the two directions are completely parallel, but also means that the directions are substantially parallel, that is, there is a difference of, for example, a few percent. Furthermore, in the following description, when the term "insulation" is used, it means "electrical insulation."

[0020] [1 General description of the energy storage device] First, a general description of the energy storage device 10 according to the present embodiment will be given. Fig. 1 is a perspective view showing the appearance of the energy storage device 10 according to the embodiment. Fig. 2 is an exploded perspective view showing each component when the energy storage device 10 according to the embodiment is disassembled. Fig. 3 is an exploded perspective view showing each component when the energy storage device 10 according to the embodiment is further disassembled. Note that Fig. 3 is an exploded perspective view showing components of the energy storage device 10 other than the exterior body 100 and the bus bar 700.

[0021] The power storage device 10 is a device capable of charging with electricity from an external source and discharging electricity to the external source, and in this embodiment, has a substantially rectangular parallelepiped shape. For example, the power storage device 10 is a battery module (battery assembly) used for power storage or power supply purposes. Specifically, the power storage device 10 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 10 can also be used as a stationary battery for home or business use.

[0022] As shown in Fig. 1, the energy storage device 10 includes an exterior housing 100. As shown in Figs. 2 and 3, the exterior housing 100 accommodates a plurality of energy 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 plurality of bus bars 700, and the like. In addition to the above components, the energy storage device 10 may also include a bus bar holder on which the bus bars 700 are placed, a circuit board for monitoring the charge and discharge states of the energy storage elements 200, electrical devices such as fuses, relays, and connectors, and an exhaust unit for exhausting gas discharged from the energy storage elements 200 to the outside of the exterior housing 100.

[0023] 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 10. The exterior body 100 is arranged outside the plurality of energy storage elements 200, the plurality of intermediate spacers 300, the pair of end plates 400, the pair of side plates 500, the plurality of bus bars 700, etc., and fixes the plurality of energy storage elements 200, etc. at predetermined positions to protect them from impacts and the like. The exterior housing 100 is formed from an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or a composite material thereof, or from a metal or the like with an insulating coating. The exterior housing 100 thereby prevents the energy storage device 200 and the like from coming into contact with external metal members and the like. Note that the exterior housing 100 may be formed from a conductive material such as a metal as long as the electrical insulation of the energy storage device 200 and the like is maintained.

[0024] 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.

[0025] 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 (first direction). The size, shape, and number of the energy storage elements 200 to be arranged are not limited, and for example, only two energy storage elements 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.

[0026] The bus bar 700 is a flat, rectangular member connected to the energy storage elements 200. The bus bar 700 is disposed above the energy storage elements 200, and is connected (joined) to the electrode terminals 240 (see FIG. 4, etc.) of the energy storage elements 200 and to the external terminals 121. In other words, the bus bar 700 connects the electrode terminals 240 of the energy storage elements 200 to each other, and also connects the electrode terminals 240 of the energy storage elements 200 at the ends to the external terminals 121.

[0027] In the present embodiment, bus bar 700 and electrode terminal 240 or external terminal 121 are connected (joined) by welding, but may also be connected (joined) by bolts or the like. Bus bar 700 is formed of, for example, a conductive member made of a metal such as aluminum, an aluminum alloy, copper, a copper alloy, or nickel, or a combination thereof, or a conductive member other than a metal. In the present embodiment, bus bar 700 connects two energy storage elements 200 in parallel to form four sets of energy storage element groups, and these four sets of energy storage element groups are connected in series. Note that the connection form of bus bar 700 is not particularly limited, and a plurality of energy storage elements 200 may be connected in any combination in series or in parallel.

[0028] The intermediate spacer 300 is a flat, rectangular member that is arranged to the side of the energy storage element 200 (in the positive or negative X-axis direction) and electrically insulates the energy storage element 200 from other members. The intermediate spacer 300 also has the function of holding the energy storage element 200 and positioning the energy storage element 200. Here, of the multiple intermediate spacers 300, the intermediate spacers 300 arranged between the energy storage elements 200 (energy storage element group) are also referred to as intermediate spacers 310 to 330, and the intermediate spacer 300 arranged between the energy storage element 200 (energy storage element group) and the end plate 400 is also referred to as intermediate spacer 340. In other words, the multiple energy storage elements 200 and the multiple intermediate spacers 300 (intermediate spacers 310 to 340) are arranged side by side in the X-axis direction.

[0029] The intermediate spacers 310 to 330 are spacers (intermediate spacers) disposed between two adjacent energy storage elements 200 to electrically insulate the two energy storage elements 200. The intermediate spacer 310 is disposed between the intermediate spacers 320 and 330 and is thicker and more rigid than the intermediate spacers 320 and 330. The intermediate spacer 310 is formed of a metal member such as aluminum, aluminum alloy, iron, stainless steel, or plated steel sheet. The material of the intermediate spacer 310 is not particularly limited, and it may be formed of a highly rigid insulating member or may be subjected to an insulating treatment. The intermediate spacers 320 and 330 are formed of, for example, an electrically insulating member such as any of the resin materials usable for the exterior body 100 described above, or a heat-insulating member such as a damper material formed by collecting and bonding mica pieces.

[0030] The intermediate spacer 340 is a spacer that is disposed between the end energy storage elements 200 and the end plates 400 (410, 420) and electrically insulates the end energy storage elements 200 from the end plates 400 (410, 420). The intermediate spacer 340 is formed, for example, from an electrically insulating material such as any of the resin materials that can be used for the exterior body 100 described above, or from a heat-insulating material such as a damper material.

[0031] The end plates 400 and the side plates 500 are restraining members that compress (restrain) the energy storage elements 200 from the outside in the arrangement direction (X-axis direction) of the multiple energy storage elements 200. In other words, the end plates 400 and the side plates 500 sandwich the multiple energy storage elements 200 from both sides in the arrangement direction, thereby compressing (restraining) each of the energy storage elements 200 included in the multiple energy storage elements 200 from both sides in the arrangement direction.

[0032] The end plate 400 and the side plate 500 are formed from metal members such as aluminum, aluminum alloy, iron, stainless steel, plated steel plate, etc. The material of the end plate 400 and the side plate 500 is not particularly limited, and they may be formed from a highly rigid insulating member or may be subjected to an insulating treatment.

[0033] Specifically, the end plates 400 are plate-shaped members (sandwiching members) arranged on both sides of the energy storage elements 200 and the intermediate spacers 300 (310-340) in the X-axis direction, and sandwich and hold the energy storage elements 200 and the like from both sides in the arrangement direction (X-axis direction). Of the pair of end plates 400, the end plate 400 on the positive side of the X-axis is also referred to as end plate 410, and the end plate 400 on the negative side of the X-axis is also referred to as end plate 420. In other words, the pair of end plates 410 and 420 are arranged at positions sandwiching the energy storage elements 200 and the intermediate spacers 300 in the X-axis direction (predetermined direction) and sandwich them. Details of the end plates 400 will be described later.

[0034] The side plate 500 is a plate-like member attached at both ends to a pair of end plates 400 (410, 420) and connecting the pair of end plates 400 to restrain the plurality of energy storage elements 200 and the plurality of intermediate spacers 300 (310-340). In other words, the side plate 500 is a connecting member that extends in the X-axis direction so as to straddle the plurality of energy storage elements 200 and the plurality of intermediate spacers 300 and is connected to the pair of end plates 400. By being connected to the pair of end plates 400, the side plate 500 applies a restraining force to the plurality of energy storage elements 200 etc. in the arrangement direction (X-axis direction).

[0035] 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.

[0036] 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 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 joined by being tightened with 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 is also referred to as side plate 501, and the side plate 500 on the negative side of the Y-axis is also referred to as side plate 502.

[0037] Furthermore, a plurality of drawn portions 510 for increasing strength are formed at the bent corners of the side plate 500. Each drawn portion 510 is formed by drawing so as to be convex inward at the corner.

[0038] [2. Explanation of the energy storage element] Next, the configuration of the energy storage element 200 will be described in detail. Fig. 4 is a perspective view showing the configuration of the energy storage element 200 according to the embodiment. Specifically, Fig. 4 shows an enlarged view of the appearance of one of the energy storage elements 200 shown in Fig. 3. Note that the plurality of energy storage elements 200 all have the same configuration, and therefore, the configuration of one of the energy storage elements 200 will be described in detail below.

[0039] 4, the energy storage element 200 includes a container 210, a pair of electrode terminals 240 (positive and negative), and an upper gasket 250. The container 210 also contains a lower gasket, an electrode assembly, a pair of current collectors (positive and negative), an electrolyte (nonaqueous electrolyte), and the like, although these are not shown in the figure. There are no particular limitations on the type of electrolyte as long as it does not impair the performance of the energy storage element 200, and various types can be selected.

[0040] 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 (registered trademark), Teflon (registered trademark), silicone, polyisoprene, and polyvinyl chloride.

[0041] 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 of the container body 220, 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. 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.

[0042] 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 adjacent to the long sides 211 and the short sides 212.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] [3 End plate explanation] Next, the configuration of end plate 400 (410, 420) will be described in detail. 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.

[0048] 5 and 6 are exploded perspective views showing the configuration of an end plate 410 according to an embodiment. Specifically, Fig. 5 is an exploded perspective view of the end plate 410 as viewed from the positive direction of the X-axis, and Fig. 6 is an exploded perspective view of the end plate 410 as viewed from the negative direction of the X-axis. Fig. 7 is a plan view of the end plate 410 according to an embodiment as viewed from the positive direction of the X-axis. In Fig. 7, a pair of side plates 500 are shown by two-dot chain lines, and the end plate 410 has a non-placement region N in the Z-axis direction where the pair of side plates 500 are not placed.

[0049] As shown in FIGS. 5 to 7, the end plate 410 has a first plate 430 and a second plate 460, which are joined together by welding, for example, to form an integrated body.

[0050] The first plate 430 is a plate material laminated on the main surface of the second plate 460 in the positive direction of the X axis, and is a metal plate in this embodiment. Specifically, the first plate 430 has a plurality of protrusions 440 and a plurality of recesses 490. When the first plate 430 is viewed as a whole, each protrusion 440 is a portion protruding in the positive direction of the X axis, and each recess 490 is a portion recessed in the negative direction of the X axis. The top walls 443 of each protrusion 440 are flat plate portions parallel to the YZ plane and arranged at the same position in the X axis direction. Similarly, the bottom walls 491 of each recess 490 are flat plate portions parallel to the YZ plane and arranged at the same position in the X axis direction.

[0051] The multiple protrusions 440 include a pair of first protrusions 441 extending in the Y-axis direction and a pair of second protrusions 442 extending in the Z-axis direction. Specifically, each first protrusion 441 extends continuously over the entire Y-axis direction of the first plate 430. Of the pair of first protrusions 441, one first protrusion 441 is disposed in an upper portion of the first plate 430, and the other first protrusion 441 is disposed in an intermediate portion of the first plate 430 in the Z-axis direction. The lower portion of the other first protrusion 441 extends into the non-arrangement region N over the entire width (total length in the Y-axis direction) (see FIG. 7).

[0052] A pair of through holes 445 is provided in the top wall 443 of each first protrusion 441. Specifically, each through hole 445 is disposed at both ends of each top wall 443 in the Y-axis direction and penetrates in the X-axis direction. A pair of nuts 450 is fixed to the surface of each top wall 443 facing the negative X-axis direction (see FIG. 6). Each nut 450 is fixed to each top wall 443 by welding or the like so that the screw hole communicates with each through hole 445.

[0053] A connecting member 500a is fastened and coupled to each nut 450 provided in each first protrusion 441, thereby coupling the end of the side plate 500 and the first plate 430. Specifically, with the end of the side plate 501 overlapping the end of the first plate 430 in the positive Y-axis direction, each connecting member 500a is fastened and coupled to each nut 450 via each through hole 445 in the positive Y-axis direction. With the end of the side plate 502 overlapping the end of the first plate 430 in the negative Y-axis direction, each connecting member 500a is fastened and coupled to each nut 450 via each through hole 445 in the negative Y-axis direction. In this way, each through hole 445 in the first plate 430 is a coupling position with the pair of side plates 500. Each first protrusion 441 extends continuously to connect the coupling positions with the pair of side plates 500.

[0054] Furthermore, a positioning hole 446 for positioning with the second plate 460 is formed in the top wall 443 of each first protrusion 441 at the midpoint between the pair of through holes 445 so as to penetrate in the X-axis direction.

[0055] Each second protrusion 442 extends continuously from the other first protrusion 441 to the lower end of the first plate 430. Each second protrusion 442 is arranged in a non-arrangement region N of the end plate 410 (see FIG. 7). Specifically, of a pair of second protrusions 442, one second protrusion 442 is arranged in a position closer to the positive direction of the Y axis within the non-arrangement region N, and the other second protrusion 442 is arranged in a position closer to the negative direction of the Y axis within the non-arrangement region N. A positioning hole 446 for positioning with the second plate 460 is formed in the top wall 443 of each second protrusion 442 at an intermediate position in the Z axis direction so as to penetrate in the X axis direction.

[0056] The multiple recesses 490 are each portion of the first plate 430 where the multiple first protrusions 441 are not formed. Specifically, within the first plate 430, the recesses 490 are each a portion above one of the first protrusions 441, a portion between a pair of first protrusions 441, a portion in the positive Y-axis direction of one of the second protrusions 442, a portion in the negative Y-axis direction of the other second protrusion 442, and a portion between the pair of second protrusions 442.

[0057] As described above, the first plate 430 is provided with a first convex portion 441 extending to connect the connecting positions of the pair of side plates 500, and a second convex portion 442 extending in a direction (Z-axis direction) intersecting the predetermined direction (X-axis direction) in which the first convex portion 441 extends. Therefore, even if bending forces act on the first plate 430 in various directions, the first convex portion 441 and the second convex portion 442 can suppress bending of the first plate 430. For example, even if the central portion of the first plate 430 is bent into a curved shape that is convex toward the positive direction of the X-axis as viewed in the Z-axis direction, the pair of first convex portions 441 extending along the Y-axis direction suppresses bending of the first plate 430. Furthermore, even if the lower edge of the first plate 430 is bent in the positive direction of the X-axis as viewed in the Y-axis direction, the pair of second convex portions 442 extending along the Z-axis direction suppresses bending of the first plate 430.

[0058] The second plate 460 is a plate material, which is a flat metal plate in this embodiment, disposed between the first plate 430 and the plurality of energy storage elements 200 and overlaps the first plate 430. Specifically, the second plate 460 is disposed between the intermediate spacer 340 in the positive direction of the X-axis and the first plate 430, and is directly overlapped thereon.

[0059] 7, second plate 460 is formed in a shape such that both end portions in the Y-axis direction protrude from first plate 430. Specifically, both end portions in the Y-axis direction of second plate 460 are protruding portions 461 that protrude continuously from first plate 430 over the entire Z-axis direction. A notch 462 extending in the Z-axis direction is formed at the lower end of each protruding portion 461.

[0060] The portion of the second plate 460 between the pair of protruding portions 461 is an overlapping portion 463 that overlaps the first plate 430 as viewed in the X-axis direction. The overlapping portions 463 are overlapped with the bottom walls 491 of all of the recessed portions 490 of the first plate 430, and at least a portion of the overlapping portions 463 is welded, thereby integrating the first plate 430 and the second plate 460.

[0061] The overlapping portion 463 has a plurality of positioning holes 464 formed therethrough in the X-axis direction. The plurality of positioning holes 464 are arranged at positions corresponding to the positioning holes 446 of the first plate 430. During manufacturing, the positioning holes 446 of the first plate 430 and the positioning holes 464 of the second plate 460 are connected to each other, and a jig is inserted into the positioning holes 446, 464. This positions the first plate 430 and the second plate 460. By welding in this state, the first plate 430 and the second plate 460 are welded in the correct position and integrated.

[0062] Here, second plate 460 is formed in a flat plate shape and is superimposed on bottom walls 491 of the plurality of recesses 490 of first plate 430. For example, when first plate 430 receives an external impact, stress is transmitted from the plurality of recesses 490 to second plate 460, but second plate 460 is in contact with the plurality of recesses 490, and therefore the stress can be dispersed. Therefore, it is possible to prevent large stress from being applied to energy storage elements 200, and damage to energy storage elements 200 can be further suppressed.

[0063] Furthermore, the second plate 460 is formed in a flat plate shape, while the first plate 430 has an uneven structure. In other words, the second plate 460 has a smaller surface area than the first plate 430, and therefore the second plate 460 can be made lighter than the first plate 430. On the other hand, as shown in FIG. 7 , the second plate 460 has a larger projected area as viewed in the X-axis direction than the first plate 430. Therefore, it is possible to disperse the impact received by the first plate 430 over a wider range.

[0064] [4. Explanation of effects] As described above, in energy storage device 10 according to the embodiment of the present invention, end plate 400 is provided with first convex portions 441 extending to connect the connection positions of a pair of side plates 500, and second convex portions 442 extending in a direction intersecting the predetermined direction in which first convex portions 441 extend. Therefore, even if bending forces act on end plate 400 in various directions, first convex portions 441 and second convex portions 442 can suppress bending of end plate 400. In other words, the rigidity of end plate 400 itself is increased, and deformation of end plate 400 can be suppressed. This suppresses expansion of energy storage elements 200 and damage to exterior body 100, and suppresses a decrease in the reliability of energy storage device 10.

[0065] In this embodiment, the first plate 430 is provided with an uneven structure to increase its rigidity, and therefore, it is possible to prevent the first plate 430 from becoming heavy.

[0066] Here, the non-arrangement region N of the end plate 400 in the third direction (Z-axis direction) where no side plate 500 is arranged is susceptible to bending force originating from the connecting position because no side plate 500 is arranged. In the present embodiment, the second convex portion 442 is provided in the non-arrangement region N, and the non-arrangement region N of the end plate 400 can be reinforced by the second convex portion 442, thereby suppressing bending of that portion. In other words, deformation of the easily deformable portion of the end plate 400 can be suppressed, and deformation of the end plate 400 can be more reliably suppressed. This makes it possible to more reliably suppress expansion of the energy storage elements 200 and damage to the exterior body 100, and to more reliably suppress a decrease in the reliability of the energy storage device 10.

[0067] Since second protrusion 442 extends from the other first protrusion 441 to the lower edge of end plate 400, second protrusion 442 can increase the rigidity up to the lower edge of end plate 400. This further increases the rigidity of end plate 400 itself, making it possible to more reliably suppress deformation of end plate 400. This makes it possible to more reliably suppress expansion of energy storage elements 200 and damage to exterior body 100, and more reliably suppress deterioration in the reliability of energy storage device 10.

[0068] Since the end plate 400 is formed by stacking the first plate 430 and the second plate 460, it is possible to further increase the rigidity of the end plate 400 itself. This makes it possible to more reliably suppress deformation of the end plate 400. Therefore, it is possible to more reliably suppress expansion of the energy storage elements 200 and damage to the exterior body 100, and to more reliably suppress deterioration in the reliability of the energy storage device 10.

[0069] If first convex portion 441 and second convex portion 442 were separated, stress would concentrate at the boundary between them, potentially making them prone to bending. In this embodiment, first convex portion 441 and second convex portion 442 are formed continuously, which prevents end plate 400 from bending at the boundary between them. This increases the rigidity of end plate 400 itself, making it possible to more reliably prevent deformation of end plate 400.

[0070] Furthermore, if the first convex portion 441 and the second convex portion 442 protrude in opposite directions, stress may concentrate at the inverted portion, making the end plate more likely to bend. In this embodiment, the first convex portion 441 and the second convex portion 442 protrude in the same direction, so there are no inverted portions and stress is less likely to concentrate. This makes it possible to further increase the rigidity of the end plate 400 itself, and more reliably suppress deformation of the end plate 400.

[0071] [5. Explanation of Variations] Although the energy storage device 10 according to the present embodiment has been described above, the present invention is not limited to the above embodiment. The embodiment disclosed herein is illustrative 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. In the following description, the same parts as those in the above embodiment are designated by the same reference numerals, and their description may be omitted.

[0072] For example, in the above embodiment, the end plate 400 is illustrated as having the second protrusions 442 only in the non-arrangement region N. However, the second protrusions may be provided in regions other than the non-arrangement region N. FIG. 8 is a plan view showing an end plate 410a according to a modified example. In the end plate 410a shown in FIG. 8, each second protrusion 442a is continuously formed from the lower end to the upper end of the first plate 430a, and is also provided in regions other than the non-arrangement region N. Therefore, each second protrusion 442a is continuously formed with respect to each first protrusion 441a. Furthermore, each second protrusion 442a extends from one first protrusion 441a to the lower edge of the first plate 430a, and therefore the second protrusion 442a can also increase the rigidity up to the lower edge of the first plate 430a. In other words, the rigidity of the end plate 410a is increased. Note that the second protrusions may be provided in a manner that avoids the non-arrangement region.

[0073] In the above embodiment, the two-piece end plate 400 is exemplified, but a single-piece end plate consisting of only the first plate may also be used.

[0074] 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 460. 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.

[0075] In the above embodiment, an example is given of an intermediate spacer 340 being interposed between the end plate 400 and the energy storage element 200, but the end plate and the energy storage element may be directly overlapped without the intermediate spacer 340 being interposed.

[0076] In the above embodiment, a case has been exemplified in which a pair of first convex portions 441 and a pair of second convex portions 442 are provided. However, the number of first convex portions 441 and the number of second convex portions 442 provided may be any number.

[0077] In the above embodiment, the case where the first convex portion 441 extends along the Y-axis direction has been exemplified. However, the first convex portion may extend at an angle with respect to the Y-axis direction, as long as it extends to connect the connection positions of the pair of connecting members.

[0078] In the above embodiment, the case where the second convex portion 442 extends along the Z-axis direction has been exemplified. However, the second convex portion may extend at an angle to the Z-axis direction as long as it intersects with the predetermined direction in which the first convex portion extends.

[0079] In the above embodiment, the pair of end plates 400 have the same configuration. However, only one of the end plates may have the first convex portion and the second convex portion.

[0080] In the above embodiment, the case where the second protrusion 442 extends from the first protrusion 441 to the edge of the end plate 400 has been exemplified. However, the second protrusion may extend only to the middle position of the end plate 400, or may extend only to just before the edge.

[0081] 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]

[0082] 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]

[0083] 10. Energy storage device 100 exterior body 110 Exterior body 120 Exterior body lid 121 External terminal 200 Energy storage element 210 Container 211 Long side 212 short side 213 bottom 220 Container body 230 Lid 231 Gas exhaust valve 240 Electrode terminal 250 Upper gasket 300, 310, 320, 330, 340 Intermediate spacer 400, 410a, 410, 420 end plates 430, 430a First Plate 440 Convex 441, 441a First convex part 442, 442a Second convex part 443 Ceiling wall 445 Through hole (connection position) 446, 464 Positioning holes 450 Nut 460 Second Plate 461 Protrusion 462 Notch 463 Overlapping section 490 recess 491 Bottom wall 500, 501, 502 Side plates (connecting members) 500a connecting member 510 Constriction section 700 Busbar N non-placement area

Claims

1. A plurality of storage elements arranged in a first direction; a pair of end plates that sandwich the plurality of energy storage elements in the first direction; a pair of connecting members extending along the first direction, the connecting members being connected to the pair of end plates in a state in which the plurality of energy storage elements are sandwiched between the connecting members in a second direction intersecting the first direction, At least one of the pair of end plates is a first protrusion extending to connect the respective connection positions of the pair of connection members; a second protrusion extending in a direction intersecting the predetermined direction in which the first protrusion extends, the end plate is formed by stacking a first plate and a second plate, the first plate is a metal plate having an uneven structure that forms the first convex portion and the second convex portion, The second plate is a flat metal plate. Energy storage device.

2. the end plate has a non-placement region in which the pair of connecting members are not placed in a third direction intersecting the first direction and the second direction, The second convex portion is disposed in the non-disposition region. The power storage device according to claim 1 .

3. The second protrusion extends from the first protrusion toward the edge of the end plate. The electricity storage device according to claim 1 or 2.

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