Energy storage device

Abstract

This power storage device comprises: a power storage element; and a spacer disposed below the power storage element. The spacer includes: a spacer body; and a projection section that projects downwards from a second edge section, of edge sections of the spacer body in the intersection direction that intersects the vertical direction, the second edge section being lower than a first edge section adjacent thereto.

Description

Technical Field

[0006] , , ,

[0005] ,

[0001] The present invention relates to a power storage device including a power storage element and a spacer.

Background Art

[0002] Conventionally, a power storage device including a power storage element and a spacer disposed below the power storage element has been known. Patent Document 1 discloses an assembled battery (power storage device) including a battery cell (power storage element) and a cell holder (spacer) that holds the battery cell, and the cell holder is provided with a first discharge hole for discharging condensed water.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration where a spacer is disposed below a power storage element, if a liquid such as an electrolytic solution that has leaked from the power storage element to the spacer or condensed water that has accumulated in the spacer drips downward from the spacer, there is a risk that the power storage element and a conductive member (such as another power storage element) below the spacer will be short-circuited by the liquid. For example, in the above conventional power storage device, since the first discharge hole for discharging condensed water is provided in the spacer (cell holder), when the condensed water is discharged from the first discharge hole, there is a risk that the power storage element (battery cell) and the conductive member below the spacer (cell holder) will be short-circuited by the condensed water.

[0005] The present invention has been newly made by the inventors of the present application paying attention to the above problems, and an object thereof is to provide a power storage device capable of suppressing short-circuiting of a power storage element with a liquid with a conductive member below.

Means for Solving the Problems

[0007] This invention can be implemented not only as an energy storage device, but also as a spacer. [Effects of the Invention]

[0008] According to the energy storage device of the present invention, it is possible to suppress short circuits between the energy storage element and the conductive member below it and the liquid. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing the external appearance of an energy storage device according to an embodiment. [Figure 2] Figure 2 is an exploded perspective view showing the various components of the energy storage unit according to the embodiment. [Figure 3] Figure 3 is an exploded perspective view showing the individual components of the energy storage unit according to the embodiment. [Figure 4] Figure 4 is an exploded perspective view showing the individual components of the energy storage element according to the embodiment. [Figure 5] Figure 5 is a perspective view showing the configuration of the intermediate spacer according to the embodiment. [Figure 6] Figure 6 is a perspective view and a cross-sectional view showing the positional relationship between the first exterior body, energy storage element, and end spacer and the intermediate spacer according to the embodiment. [Modes for carrying out the invention]

[0010] An energy storage device according to one aspect of the present invention is an energy storage device comprising an energy storage element and a spacer disposed below the energy storage element, wherein the spacer has a spacer body and a projection that protrudes downward from a second end which is lower in height than an adjacent first end, among the ends in the intersecting direction that intersects the vertical direction of the spacer body.

[0011] According to this, in an energy storage device, the spacer below the energy storage element has a protrusion that extends downward from a second end, which is lower in height than the adjacent first end, at the end in the intersecting direction that intersects the vertical direction of the spacer body. In this way, by providing a protrusion that extends downward from a second end, which is lower in height than the first end of the spacer body, liquids such as electrolyte or condensation water accumulated in the spacer can be guided downward from the second end by the protrusion and discharged. This prevents the energy storage element from short-circuiting with the conductive member below due to the liquid.

[0012] The protruding portion may have a first groove that is recessed in the intersecting direction and extends in the vertical direction.

[0013] According to this, in the spacer, the protruding portion has a first groove, which acts as a liquid flow path, and the liquid easily flows down through the first groove. Therefore, when the liquid accumulated in the spacer is discharged downward by the protruding portion, it can be easily guided downward and discharged.

[0014] The energy storage device may further include other energy storage elements positioned below the spacer, and the protrusion may be positioned to protrude lower than the other energy storage elements.

[0015] According to this, in the spacer, the protruding portion is positioned to protrude lower than the other energy storage elements below the spacer. Therefore, when the liquid accumulated in the spacer is discharged downward by the protruding portion, the liquid is discharged below the other energy storage elements. This prevents the liquid from short-circuiting the energy storage element with the other energy storage elements below it.

[0016] The first end portion may be a wall portion protruding upward, and the second end portion may be a recess recessed downward from the wall portion.

[0017] According to this, in the spacer, since the first end portion is a wall portion and the second end portion is a recess recessed from the wall portion, the liquid accumulated in the spacer is suppressed from falling from the first end portion and is likely to fall from the second end portion. Thereby, it is possible to suppress the liquid from falling from a location other than the protruding portion, and it becomes easier for the liquid to be discharged downward by the protruding portion from the second end portion.

[0018] The spacer body may have a second groove portion that is a groove portion extending toward the second end portion.

[0019] According to this, in the spacer, since the second groove portion extending toward the second end portion is provided in the spacer body, the second groove portion serves as a flow path for the liquid, and the liquid accumulated on the spacer body can be easily guided to the second end portion. Thereby, the liquid can be easily discharged downward by the protruding portion from the second end portion.

[0020] Hereinafter, a power storage device according to an embodiment (including a modified example thereof) of the present invention will be described while referring to the drawings. Each of the embodiments described below shows comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, manufacturing processes, order of manufacturing processes, etc. shown in the following embodiments are examples and are not intended to limit the present invention. In each figure, dimensions and the like are not strictly shown. In each figure, the same or similar components are denoted by the same reference numerals.

[0021] In the following description and drawings, the longitudinal direction of the exterior of the power storage device, the arrangement direction of a plurality of power storage elements such as the first power storage element and the second power storage element, the arrangement direction of the power storage unit and the control unit, the opposing direction of the short side surfaces of the container of the power storage element, or the arrangement direction of a pair of electrode terminals in one power storage element is defined as the X-axis direction. The arrangement direction of the power storage element and the bus bar, or the arrangement direction of the main body and the lid of the container of the power storage element is defined as the Y-axis direction. The arrangement direction of the main body and the lid of the exterior, the arrangement direction of the power storage element and the restraint, the arrangement direction of the power storage element and the spacer, the opposing direction of the long side surfaces of the container of the power storage element, the stacking direction of the electrode plates of the electrode body of the power storage element, 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. Depending on the usage mode, it is conceivable that 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.

[0022] In the following description, the X-axis plus direction indicates the arrow direction of the X-axis, and the X-axis minus direction indicates the direction opposite to the X-axis plus direction. The same applies to the Y-axis direction and the Z-axis direction. Hereinafter, the Z-axis direction may also be referred to as the first direction, the Y-axis direction may also be referred to as the second direction or the intersecting direction, and the X-axis direction may also be referred to as the third direction. Expressions indicating relative directions or postures such as parallel and orthogonal strictly include cases where they are not exactly in that direction or posture. For example, two directions being orthogonal 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 a few percent.

[0023] (Embodiment) [1 General description of the power storage device 1] First, the schematic configuration of the power storage device 1 in this embodiment will be described. FIG. 1 is a perspective view showing the appearance of the power storage device 1 according to this embodiment. FIGS. 2 and 3 are exploded perspective views showing each component of the power storage unit 10 according to this embodiment disassembled. FIG. 3 shows each component fixed to the first exterior 110 of the power storage unit 10 shown in FIG. 2 disassembled.

[0024] The energy storage device 1 is a device that can charge electricity from an external source and discharge electricity to the outside, and in this embodiment, it has a substantially rectangular parallelepiped shape. For example, the energy storage device 1 is a battery module (battery pack) used for power storage or power supply purposes. Specifically, the energy storage device 1 is used as a battery for driving or starting the engine of mobile vehicles such as automobiles, motorcycles, watercraft, ships, snowmobiles, agricultural machinery, construction machinery, or railway vehicles for electric railways. Examples of automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and gasoline automobiles. Examples of railway vehicles for electric railways include electric trains, monorails, linear motor cars, and hybrid trains equipped with both diesel engines and electric motors. The energy storage device 1 can also be used as a stationary battery for household use or for generators, etc.

[0025] As shown in Figures 1 to 3, the energy storage device 1 comprises an energy storage unit 10 and a control unit 20. Hereinafter, the portion of the energy storage device 1 containing the energy storage element 400 will be referred to as the energy storage unit 10, and the portion containing the control equipment for controlling the energy storage element 400 will be referred to as the control unit 20. The energy storage unit 10 has an outer casing 100 and a first reinforcing member 200. Inside the outer casing 100 are the energy storage element 400, spacers 500, restraining members 600, busbar frame 700, busbars 800, conductive members 900, and the control unit 20, etc. The outer casing 100 has a pair of external terminals 21 and 22 (positive and negative sides) and a connector 23. Each component will be described in detail below.

[0026] [1.1 Description of the outer casing 100] The outer casing 100 is a box-shaped (approximately rectangular parallelepiped) container (module case) that constitutes the outer casing of the energy storage device 1. The outer casing 100 is positioned outside the energy storage elements 400, etc., and fixes these energy storage elements 400, etc. in a predetermined position, protecting them from impacts, etc. The outer casing 100 includes a first outer casing 110, a second outer casing 120, a fixing member 130, a gasket 140, and a second reinforcing member 300.

[0027] The first outer casing 110 is a flat rectangular member that constitutes the main body of the outer casing 100, on which the energy storage element 400 and the like are mounted and fixed. The second outer casing 120 is a bottomed rectangular cylindrical member that constitutes the lid of the outer casing 100, positioned in the positive Z-axis direction of the first outer casing 110, and connected to the first outer casing 110 to cover the energy storage element 400 and the like. The second outer casing 120 has an opening formed on the negative Z-axis side, and the first outer casing 110 is positioned to close this opening in the second outer casing 120.

[0028] The first outer casing 110 is made of a highly rigid material such as stainless steel, aluminum, aluminum alloy, iron, steel plate, or a metal material that has been treated with insulating coating or other insulating treatment, from the viewpoint of ensuring safety (resistance to crushing). The second outer casing 120 is made of a resin material (insulating material) such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyetherether ketone (PEEK), tetrafluoroethylene perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or a composite material thereof, from the viewpoint of reducing weight. The first outer casing 110 may be made of the same resin material as the second outer casing 120, but it is preferable that it be made of a highly rigid material. The second outer casing 120 may be formed from the same metal material as the first outer casing 110.

[0029] The first exterior body 110 has a first connecting portion 111, mounting bases 113, 114 and 115, and an exterior body protrusion 116. The second exterior body 120 has a second connecting portion 121.

[0030] The first connecting portion 111 is an annular portion (flange portion) in a top view (viewed from the Z-axis direction) located on the outer circumference of the first exterior body 110. The first connecting portion 111 is located opposite the second connecting portion 121 of the second exterior body 120 and is superimposed on the second connecting portion 121 to connect to the second connecting portion 121. The second connecting portion 121 is an annular portion (flange portion) in a top view located on the outer circumference of the second exterior body 120. The second connecting portion 121 is located opposite the first connecting portion 111 and is superimposed on the first connecting portion 111 to connect to the first connecting portion 111. The first connecting portion 111 and the second connecting portion 121 are connecting portions that are superimposed on each other in the Z-axis direction (first direction) and connect to each other, and extend in the Y-axis direction (second direction intersecting the first direction) and the X-axis direction (third direction intersecting the first and second directions).

[0031] Mounting bases 113 and 114 are components to which the restraint body 600 is attached. Specifically, mounting base 113 is positioned at the Y-axis negative end of the first outer casing 110, and the Y-axis negative side portion of the first restraint body 610 (described later) of the restraint body 600 is attached to it. Mounting base 114 is positioned at the Y-axis positive end of the first outer casing 110, and the Y-axis positive side portion of the first restraint body 610 is attached to it. More specifically, mounting bases 113 and 114 have bolt portions, and the restraint body 600 (first restraint body 610) is attached to mounting bases 113 and 114 by fastening these bolt portions to nuts.

[0032] The mounting base 115 is a component to which the conductive member 900 is attached. Specifically, the mounting base 115 is located at the center of the first outer casing 110 in the X-axis direction and at the end in the positive Y-axis direction, and the mounting portions 913 and 923 of the conductive member 900, described later, are attached to it. More specifically, the mounting base 115 has a bolt portion, and the conductive member 900 (mounting portions 913 and 923) is attached to the mounting base 115 by fastening the bolt portion to a nut.

[0033] The outer casing protrusion 116 is a protrusion that projects toward the energy storage element 400. Specifically, the outer casing protrusion 116 is located in the center of the first outer casing 110 in the Y-axis direction and is a rectangular, bulging protrusion (bulge) in a top view that projects toward the positive Z-axis direction. Four outer casing protrusions 116 are arranged in a line along the X-axis direction, corresponding to the four energy storage elements 400 arranged in the X-axis direction. Each outer casing protrusion 116 is positioned opposite the center of the long side surface 411a of the energy storage element 400, which will be described later, and presses against the center of the energy storage element 400.

[0034] Within the second outer casing 120, control wires (also called communication lines, control lines, communication cables, or control cables) that transmit information such as the voltage or temperature of the energy storage element 400 are connected to the control unit 20. This allows information such as the voltage or temperature of the energy storage element 400 to be transmitted between the control unit 20 and the control unit 20. The control unit 20 is electrically connected to the connector 23, thereby transmitting this information to the outside.

[0035] The gasket 140 is a gasket positioned between the first outer casing 110 and the second outer casing 120. Specifically, the gasket 140 is a rectangular annular O-ring in top view, positioned between the first connecting portion 111 and the second connecting portion 121. More specifically, the gasket 140 is positioned between the first connecting portion 111 and the second connecting portion 121, compressed between them. The gasket 140 is formed of, for example, rubber (natural rubber, synthetic rubber), or any resin material usable for the second outer casing 120, such as PC, PP, or PE.

[0036] The second reinforcing member 300 is positioned to sandwich the second exterior body 120 between the first exterior body 110 and the second exterior body 120, and extends along the outer periphery of the first exterior body 110 and the second exterior body 120. The second reinforcing member 300 is positioned to sandwich the second connecting portion 121 between the first connecting portion 111 and the second connecting portion 121, and extends in the X-axis direction or the Y-axis direction (third direction or second direction). In this embodiment, two second reinforcing members 301 extending in the X-axis direction (third direction) are positioned for the first connecting portion 111 and the second connecting portion 121 on both sides in the Y-axis direction. Two second reinforcing members 302 extending in the Y-axis direction (second direction) are positioned for the first connecting portion 111 and the second connecting portion 121 on both sides in the X-axis direction. As a result, four second reinforcing members 300 (two second reinforcing members 301 and two second reinforcing members 302) are positioned over almost the entire outer periphery of the first exterior body 110 and the second exterior body 120. In other words, the second reinforcing member 300 extends across multiple fixing members 130.

[0037] The second reinforcing member 300 is made of a metal material such as stainless steel, aluminum, aluminum alloy, iron, or steel plate, or a metal material that has been subjected to an insulating treatment such as insulating coating, which is a highly rigid material. As described above, the first connecting portion 111 is, for example, a metal (high rigidity) flange portion, and the second connecting portion 121 is, for example, a resin (low rigidity) flange portion. For this reason, the second connecting portion 121 has lower rigidity than at least one of the first connecting portion 111 and the second reinforcing member 300. In other words, at least one of the first connecting portion 111 and the second reinforcing member 300 (in this embodiment, both the first connecting portion 111 and the second reinforcing member 300) has higher rigidity than the second connecting portion 121. In this embodiment, the second connecting portion 121 has lower rigidity than both the first connecting portion 111 and the second reinforcing member 300.

[0038] High (or low) rigidity means being strong (or weak) against external forces, and is defined as a state in which dimensional changes are small (or large) in response to bending or torsional forces. For example, the second connection part 121 is said to have lower rigidity than the first connection part 111 if, when the same force is applied to the central part of an area of ​​the same size for both the first connection part 111 and the second connection part 121, the dimensional change (amount of deflection) is greater for the second connection part 121. Alternatively, it can be said that the force required to produce the same dimensional change is smaller for the second connection part 121 than for the first connection part 111.

[0039] The second connecting portion 121 only needs to have lower overall rigidity than at least one of the first connecting portion 111 and the second reinforcing member 300. In other words, the second connecting portion 121 may have lower material rigidity (be made of a material with low rigidity) or lower structural rigidity (be configured in a shape with low rigidity) than at least one of the first connecting portion 111 and the second reinforcing member 300.

[0040] The fixing member 130 comprises a first fixing member 131 and a second fixing member 132. The first fixing member 131 and the second fixing member 132 are connected (joined) to each other and are members that connect (join) the first exterior body 110 and the second exterior body 120. Specifically, a plurality of second fixing members 132 are arranged at approximately equal intervals in the first connection part 111, and a plurality of first fixing members 131 are arranged in a row at positions corresponding to the second fixing members 132 in the second connection part 121. In this way, the first fixing member 131 and the second fixing member 132 connect (join) the first connection part 111 and the second connection part 121 together with the second reinforcing member 300.

[0041] In this embodiment, the first fixing member 131 is a bolt, and the second fixing member 132 is a nut to which the bolt is fastened. A through hole 111a is formed in the first connecting portion 111, a through hole 121a is formed in the second connecting portion 121, and a through hole 311 is formed in the second reinforcing member 300. The male threaded portion of the first fixing member 131 is inserted into these through holes 311, 121a, and 111a, and the male threaded portion is fastened to the female threaded portion of the second fixing member 132. As a result, the first fixing member 131 and the second fixing member 132 connect (fix) the first connecting portion 111 and the second connecting portion 121 by pressing the second reinforcing member 300 toward the second connecting portion 121 while the second connecting portion 121 is sandwiched between the first connecting portion 111 and the second reinforcing member 300.

[0042] The second fixing member 132 may be a bolt, and the first fixing member 131 may be a nut to which the bolt is fastened. The method for connecting (joining) the first exterior body 110 and the second exterior body 120 may be other methods, such as joining by riveting, crimping, clamping with clips, bonding, welding, heat sealing, ultrasonic welding, etc.

[0043] [1.2 Description of the first reinforcing member 200] The first reinforcing member 200 is a plate-shaped member that is aligned with the energy storage element 400 in the Z-axis direction (first direction) and positioned along the outer casing 100. The first reinforcing member 200 is attached to the outer surface of the outer casing 100. Specifically, the first reinforcing member 200 is a rectangular, corrugated member that extends in the X-axis direction along the first outer casing 110 in the Z-axis negative direction of the energy storage element 400 and the first outer casing 110. The first reinforcing member 200 abuts against and is attached to the outer surface of the first outer casing 110 on the Z-axis negative side. The first reinforcing member 200 may be formed by bending a plate-shaped member into a corrugated shape, or by casting (die casting), etc.

[0044] In this embodiment, the first reinforcing member 200 is attached to the first connecting portion 111 together with the second connecting portion 121 and the second reinforcing member 300 by fixing members 130 (first fixing member 131 and second fixing member 132) at both ends in the X-axis direction. Specifically, the first reinforcing member 200 has reinforcing member connecting portions 210 with through holes 211 formed at both ends in the X-axis direction. The male threaded portion of the first fixing member 131 is inserted into the through hole 311 of the second reinforcing member 300, the through hole 121a of the second connecting portion 121, the through hole 111a of the first connecting portion 111, and the through hole 211 of the reinforcing member connecting portion 210, and the male threaded portion is fastened to the female threaded portion of the second fixing member 132. As a result, the first reinforcing member 200 is attached to the first outer casing 110 together with the second outer casing 120 and the second reinforcing member 300.

[0045] The second reinforcing member 300 is not positioned at the locations corresponding to the fixing members 130 located at both ends in the X-axis direction and both ends in the Y-axis direction (corners in the X-axis and Y-axis directions). Therefore, at these corners, the first reinforcing member 200 is attached to the first connecting part 111 together with the second connecting part 121. In other words, at these corners, the first reinforcing member 200 is attached to the first outer casing 110 together with the second outer casing 120.

[0046] [1.3 Description of each component within the outer casing 100] The energy storage element 400 is a secondary battery (single cell) capable of charging and discharging electricity. Specifically, the energy storage element 400 is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 400 has a flat rectangular parallelepiped shape (square), and in this embodiment, eight energy storage elements 400 are arranged in the Z-axis and X-axis directions in a horizontal position (with the long side 411a of the energy storage element 400, described later, facing in the Z-axis direction). Specifically, two first energy storage elements 401 are stacked (flat) in the Z-axis direction, two second energy storage elements 402 are stacked (flat) in the Z-axis direction, two third energy storage elements 403 are stacked (flat) in the Z-axis direction, and two fourth energy storage elements 404 are stacked (flat) in the Z-axis direction. Two first energy storage elements 401, two second energy storage elements 402, two third energy storage elements 403, and two fourth energy storage elements 404 are arranged in the X-axis direction, from the negative X-axis direction to the positive X-axis direction.

[0047] The number of energy storage elements 400 is not particularly limited; any number of energy storage elements 400 may be arranged (stacked) in the Z-axis direction, or any number of energy storage elements 400 may be arranged (arranged) in the X-axis direction. The shape of the energy storage elements 400 is not limited to the above-mentioned prism shape; other shapes such as polygonal prisms, cylindrical shapes, elliptical prisms, and oblong cylindrical shapes are also acceptable. The energy storage elements 400 are not limited to non-aqueous electrolyte secondary batteries; they may be secondary batteries other than non-aqueous electrolyte secondary batteries, or capacitors. The energy storage elements 400 may not be secondary batteries, but primary batteries that allow users to use the stored electricity without charging. The energy storage elements 400 may be batteries using solid electrolytes. The energy storage elements 400 may be pouch-type energy storage elements. A detailed explanation of the configuration of the energy storage elements 400 will be given later.

[0048] The spacer 500 is a rectangular, flat spacer positioned adjacent to the energy storage element 400. The spacer 500 is positioned opposite the long side surface 411a of the energy storage element 400, in the Z-axis positive or Z-axis negative direction of the energy storage element 400. The spacer 500 is made of an insulating material such as any resin material usable for the second outer casing 120, or a material with high thermal insulation properties such as damper material.

[0049] In this embodiment, the spacer 500 consists of an intermediate spacer 510 and a pair of end spacers 520. The intermediate spacer 510 is a spacer 500 placed between two energy storage elements 400, and the end spacers 520 are spacers 500 placed between the energy storage elements 400 and the first outer casing 110 or the restraining body 600. The intermediate spacer 510 and the pair of end spacers 520 are arranged so as to sandwich the energy storage elements 400 in the Z-axis direction, electrically insulating the energy storage elements 400 from each other and from the energy storage elements 400 to the first outer casing 110 and the restraining body 600. In this embodiment, since the first to fourth energy storage elements 401 to 404 are arranged in line in the X-axis direction, the intermediate spacer 510 and the pair of end spacers 520 are placed for each of the first to fourth energy storage elements 401 to 404. An insulating sheet may be placed on the side of the energy storage element 400 instead of, or in addition to, the spacer 500. A detailed explanation of the configuration of the intermediate spacer 510 will be given later.

[0050] Each of the end spacers 520 positioned on the Z-axis positive side has two protrusions 521 formed at its Y-axis negative end, aligned in the X-axis direction. The protrusions 521 are cylindrical projections that protrude in the Z-axis positive direction and are inserted into circular through holes 611 formed in the first restraint body 610 and circular through holes 621 formed in the second restraint body 620 of the restraint body 600, which will be described later. This allows the restraint body 600 to be positioned relative to the spacers 500 (and the energy storage element 400).

[0051] The restraining body 600 is a member that, together with the first outer casing 110, sandwiches multiple energy storage elements 400, such as the first energy storage element 401 and the second energy storage element 402, in the Z-axis direction. Specifically, the first outer casing 110 and the restraining body 600 are joined to each other, sandwiching the multiple energy storage elements 400. In this way, the first outer casing 110 and the restraining body 600 restrain the multiple energy storage elements 400 in the Z-axis direction (applying a restraining force to the multiple energy storage elements 400 in the Z-axis direction). The first outer casing 110 extends in the X-axis direction so as to straddle the first energy storage elements 401 to the fourth energy storage elements 404, and the restraining body 600 individually restrains each of the first energy storage elements 401 to the fourth energy storage elements 404 together with the first outer casing 110. The restraining body 600 is formed from a metal member or the like that can be used for the first outer casing 110.

[0052] The restraint body 600 comprises a first restraint body 610 and a second restraint body 620. The first restraint body 610 is a plate-shaped member with an inverted U-shape when viewed from the X-axis direction, positioned in the Z-axis positive direction of the second restraint body 620 and joined to the first outer casing 110. The second restraint body 620 is a plate-shaped member positioned to cover almost the entire surface of the Z-axis positive side of the energy storage element 400 and the spacer 500 (end spacer 520) in the Z-axis positive direction. The first restraint body 610 and the second restraint body 620 have protrusions (bulges) extending in the Y-axis direction to improve strength, etc., but the position, shape, and number of protrusions (bulges) are not particularly limited, and the configuration may also be one in which no protrusions (bulges) are formed. The first restraint body 610 and the second restraint body 620 may be formed integrally, and the restraint body 600 may not have the second restraint body 620.

[0053] The first to fourth energy storage elements 401 to 404 are spaced apart from each other, and the restraining bodies 600, which are aligned in the X-axis direction, are also spaced apart from each other. This suppresses heat transfer between the first energy storage element 401 and the second energy storage element 402, thereby suppressing thermal influence between the first and second energy storage elements 401 and 402. An insulating material may be placed in the gap between the first and second energy storage elements 401 and 402, which further suppresses thermal influence between the first and second energy storage elements 401 and 402.

[0054] The busbar frame 700 is a flat, rectangular insulating member that provides electrical insulation between the busbar 800 and other components, and also restricts the position of the busbar 800. The busbar frame 700 is formed of, for example, any resin material that can be used for the second outer casing 120. The busbar frame 700 is positioned in the negative Y-axis direction of the multiple energy storage elements 400 and is positioned relative to the multiple energy storage elements 400, thereby positioning the busbar 800 relative to the multiple energy storage elements 400 and connecting it to the electrode terminals of the multiple energy storage elements 400.

[0055] The busbar 800 is a flat plate-shaped member arranged in the negative Y-axis direction of the multiple energy storage elements 400 and connected (joined) to the multiple energy storage elements 400 and the conductive member 900. The busbar 800 has busbars 810, 820 and 830. The busbar 810 connects the electrode terminals 420 of adjacent energy storage elements 400, which will be described later. The busbars 820 and 830 connect the electrode terminals 420 of the energy storage elements 400 to the connection parts 912 and 922 of the conductive member 900, which will be described later, thereby electrically connecting the energy storage elements 400 to the positive and negative external terminals 21 and 22.

[0056] In this embodiment, the busbar 800 and the electrode terminals 420 of the energy storage element 400 are connected (joined) by welding, but they may also be connected (joined) by bolting or the like. The connection parts 912 and 922 of the busbar 800 and the conductive member 900 are connected (joined) by bolting, but they may also be connected (joined) by welding or the like. The busbar 800 is formed of a conductive member made of metal such as aluminum, aluminum alloy, copper, copper alloy, nickel, or a combination thereof, or a conductive member other than metal. In this embodiment, the busbar 800 is configured to hold four sets of energy storage elements by connecting two energy storage elements 400 in parallel, and these four sets of energy storage elements are connected in series, but the busbar 800 may also be configured to hold all eight energy storage elements 400 in series, or in other configurations.

[0057] The conductive member 900 is a conductive member connected to the busbar 800 and the control unit 20, electrically connecting the energy storage element 400 with the external terminals 21 and 22. The conductive member 900 is a conductive member (also called a power line, power line, main circuit cable, power cable, or power cable) placed on the main current (charge / discharge current) path of the energy storage element 400. The conductive member 900 is formed of a conductive member made of metal such as aluminum, aluminum alloy, copper, copper alloy, or nickel, or a combination thereof, or a conductive member other than metal. The conductive member 900 has a conductive member 910 and a conductive member 920. The conductive member 910 has connection parts 911 and 912 and a mounting part 913. The conductive member 920 has connection parts 921 and 922 and a mounting part 923.

[0058] As described above, the connection portion 912 is the part that is connected to the bus bar 820, and the connection portion 922 is the part that is connected to the bus bar 830. The mounting portions 913 and 923 are the parts that are attached to the mounting base 115 of the first exterior body 110, as described above. In this embodiment, the conductive member 910 has a configuration in which a plate-shaped member extends from the connection portion 911 to the mounting portion 913, and an electric wire extends from the mounting portion 913 to the connection portion 912. The conductive member 920 has a configuration in which a plate-shaped member extends from the connection portion 921 to the mounting portion 923, and an electric wire extends from the mounting portion 923 to the connection portion 922.

[0059] [1.4 Description of Other Components] The control unit 20 is a device having control equipment (not shown) that controls the energy storage elements 400 within the energy storage unit 10, and specifically, it is a BMS (Battery Management System) that controls the energy storage elements 400. The control equipment located within the control unit 20 is connected to the main current path of the energy storage elements 400 and controls the energy storage elements 400, and includes, for example, a circuit board that controls the charging and discharging of the energy storage elements 400, fuses, relays, semiconductor switches such as FETs (Field Effect Transistors), and shunt resistors. The control unit 20 is housed in the outer casing 100.

[0060] The outer casing 100 has external terminals 21 and 22, which are a pair of module terminals (total terminals) for the positive and negative electrodes, located at its end in the positive X-axis direction. External terminals 21 and 22 are electrically connected to the energy storage element 400 of the energy storage unit 10 via connection parts 911 and 921. The energy storage device 1 charges with electricity from the outside and discharges electricity to the outside via these external terminals 21 and 22. For example, external terminal 21 is a positive electrode external terminal, and external terminal 22 is a negative electrode external terminal. External terminals 21 and 22 are formed of a conductive metal such as aluminum, aluminum alloy, copper, or copper alloy.

[0061] [2. Explanation of the configuration of the energy storage element 400] Next, the configuration of the energy storage element 400 will be described in more detail. In this embodiment, all eight energy storage elements 400 (two first energy storage elements 401, two second energy storage elements 402, two third energy storage elements 403, and two fourth energy storage elements 404) of the energy storage unit 10 have the same configuration, so the following description will focus on the configuration of one energy storage element 400.

[0062] Figure 4 is an exploded perspective view showing the components of the energy storage element 400 according to this embodiment, disassembled. Specifically, Figure 4 shows the energy storage element 400 shown in Figure 3 in a vertical (upright) position, with each part disassembled.

[0063] As shown in Figure 4, the energy storage element 400 comprises a container 410, a pair of electrode terminals 420 (positive and negative), and a pair of gaskets 430 (positive and negative). Inside the container 410 are a pair of gaskets 440 (positive and negative), a pair of current collectors 450 (positive and negative), and an electrode body 460. An electrolyte (non-aqueous electrolyte) is sealed inside the container 410, but it is not shown in the figure. There are no particular restrictions on the type of electrolyte as long as it does not impair the performance of the energy storage element 400, and various types can be selected. In addition to the above components, spacers placed to the side or below the electrode body 460, an insulating film enclosing the electrode body 460, or an insulating sheet covering the outer surface of the container 410 may also be provided.

[0064] The container 410 is a rectangular parallelepiped (square or box-shaped) case having a container body 411 with an opening and a container lid 412 that closes the opening of the container body 411. With this configuration, the container 410 can be sealed inside by welding the container body 411 and the container lid 412 together after the electrode body 460 and the like are placed inside the container body 411. The material of the container body 411 and the container lid 412 is not particularly limited, but it is preferable that they be weldable metals such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet.

[0065] The container body 411 is a rectangular cylindrical member with a bottom that constitutes the body of the container 410, and has an opening formed on the negative Y-axis side. The container body 411 has a pair of rectangular and planar (flat) long sides 411a on both sides in the Z-axis direction, a pair of rectangular and planar (flat) short sides 411b on both sides in the X-axis direction, and a rectangular and planar (flat) bottom surface 411c on the positive Y-axis side. The container lid 412 is a rectangular plate-like member that constitutes the lid of the container 410, and extends in the X-axis direction on the negative Y-axis side of the container body 411. The container lid 412 is provided with a gas discharge valve 412a that releases pressure when the pressure inside the container 410 rises, and an injection part (not shown) for injecting electrolyte into the container 410. Thus, the container 410 has a container body 411 and a container lid 412 that are arranged side by side in the Y-axis direction (second direction) and joined to each other. As described above, the first to fourth energy storage elements 401 to 404 are arranged in the X-axis direction (third direction), which is the longitudinal direction of the container lid 412.

[0066] The electrode body 460 is an energy storage element (power generation element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate has a positive electrode active material layer formed on a positive electrode base layer which is a current collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate has a negative electrode active material layer formed on a negative electrode base layer which is a current collector foil made of a metal such as copper or a copper alloy. As for the active material used in the positive electrode active material layer and the negative electrode active material layer, any known material can be used as long as it is capable of intercalating and releasing lithium ions. In this embodiment, the electrode body 460 is a wound type (so-called vertical winding type) electrode body formed by winding the electrode plates (positive electrode plate and negative electrode plate) around a winding axis (a virtual axis parallel to the X-axis direction) extending in the X-axis direction.

[0067] The electrode plates (positive and negative plates) of the electrode body 460 are stacked in the Z-axis direction, and therefore the Z-axis direction is also called the stacking direction. In other words, the electrode body 460 is formed by stacking the electrode plates in the stacking direction. The electrode body 460 has a pair of flat sections 461 aligned in the Z-axis direction and a pair of curved sections 462 aligned in the Y-axis direction, formed by winding the electrode plates, but the stacking direction mentioned above is the stacking direction of the electrode plates in the flat section 461. The flat section 461 is a flat part that connects the ends of the pair of curved sections 462, and the curved section 462 is a part that is curved in a semi-circular shape or the like so as to protrude in the Y-axis direction. The flat surface of the flat section 461 faces the stacking direction mentioned above. In the stacking direction mentioned above, the pair of flat sections 461 face each other. Multiple first energy storage elements 401 can be said to be aligned in this stacking direction. The same applies to the other energy storage elements 400. The X-axis direction in which the first to fourth energy storage elements 401 to 404 are arranged is also called the arrangement direction. The first to fourth energy storage elements 401 to 404 are arranged in the arrangement direction intersecting the said stacking direction.

[0068] In the electrode body 460, the positive electrode plate and the negative electrode plate are wound offset from each other in the X-axis direction. Therefore, the positive electrode plate and the negative electrode plate have portions at their respective offset ends where the active material is not formed (coated) and the base material layer is exposed (non-active material layer portion). The electrode body 460 has ends 463 at both ends in the X-axis direction that protrude from the flat portion 461 and the curved portion 462 on both sides in the X-axis direction, and where the non-active material layer portions of the positive electrode plate and the negative electrode plate are stacked and connected to the current collector 450.

[0069] The electrode body 460 may be any form of electrode body, such as a so-called horizontally wound electrode body formed by winding electrode plates around a winding axis extending in the Y-axis direction, a stacked electrode body formed by stacking multiple flat electrode plates, or a bellows-type electrode body in which electrode plates are folded in a bellows-like manner. In the case of a horizontally wound electrode body, the flat parts other than the curved portion and the connection portion (tab) with the current collector are flat parts, and in the case of stacked and bellows-type electrode bodies, the flat parts other than the connection portion (tab) with the current collector are flat parts.

[0070] The electrode terminals 420 are the terminals (positive and negative electrode terminals) of the energy storage element 400 and are positioned on the container lid 412 so as to protrude in the negative direction of the Y-axis. The electrode terminals 420 are electrically connected to the positive and negative electrode plates of the electrode body 460 via the current collector 450. The electrode terminals 420 are made of a conductive material such as aluminum, aluminum alloy, copper, or copper alloy.

[0071] The current collector 450 is a conductive member (positive electrode current collector and negative electrode current collector) electrically connected to the electrode terminal 420 and the end 463 of the electrode body 460. The current collector 450 is made of aluminum, aluminum alloy, copper, or copper alloy, etc. The gaskets 430 and 440 are flat, electrically insulating sealing members placed between the container lid 412 and the electrode terminal 420 and the current collector 450. The gaskets 430 and 440 are made of, for example, any electrically insulating resin material that can be used for the second outer casing 120.

[0072] [3. Explanation of the configuration of the intermediate spacer 510] Next, the configuration of the intermediate spacer 510 will be described in more detail. Figure 5 is a perspective view showing the configuration of the intermediate spacer 510 according to this embodiment. Specifically, Figure 5(a) is an enlarged perspective view of the intermediate spacer 510 shown in Figure 3. Figure 5(b) is an enlarged perspective view showing the configuration of the first end 514, 515 and the second end 516 of the intermediate spacer 510 in Figure 5(a) as viewed from the back side (Y-axis positive direction side).

[0073] Figure 6 is a perspective view and a cross-sectional view showing the positional relationship between the first outer casing 110, the energy storage element 400, the end spacer 520, and the intermediate spacer 510 according to this embodiment. Specifically, Figure 6(a) is a perspective view showing the configuration with the energy storage element 400, the intermediate spacer 510, and the end spacer 520 mounted on the first outer casing 110. Figure 6(b) is a cross-sectional view showing the configuration of Figure 6(a) when cut by a plane passing through the line VIb-VIb and parallel to the YZ plane.

[0074] As shown in Figures 5 and 6, the intermediate spacer 510 has a spacer body 511, a first wall portion 512, a second wall portion 513, first ends 514 and 515, a second end portion 516, and a protruding portion 517.

[0075] The spacer body 511 is a flat, rectangular portion that constitutes the body of the intermediate spacer 510, and is positioned opposite the long side surface 411a of the container 410 of the energy storage element 400, and abuts against the long side surface 411a. The spacer body 511 has a second groove 511a and a spacer protrusion 511b.

[0076] The second groove 511a is a groove that extends toward the second end 516. Specifically, the second groove 511a is formed at the Y-axis negative end of the spacer body 511 so as to extend in the X-axis direction and is connected to the second end 516. More specifically, the second groove 511a is a recess in which the Z-axis positive surface is recessed in the Z-axis negative direction, extending from one end in the X-axis direction to the other end along the Y-axis negative edge of the spacer body 511. The second groove 511a extends from the Y-axis negative and X-axis positive ends and the X-axis negative end of the spacer body 511 toward the second end 516 along the Y-axis negative edge and is connected to the second end 516.

[0077] The spacer protrusion 511b is a rectangular protrusion in top view that is positioned in the center of the spacer body 511 in the X-axis and Y-axis directions and protrudes toward the Z-axis direction. The spacer protrusion 511b is positioned to protrude toward the center of the long side surface 411a of the container 410 of the energy storage element 400, and contacts and presses against the center. In this embodiment, the spacer protrusion 511b is positioned on both sides of the spacer body 511 in the Z-axis direction, protruding toward the center of the long side surface 411a of the energy storage element 400 positioned on both sides of the spacer body 511 in the Z-axis direction, and presses against the center.

[0078] The first wall portion 512 is a flat, rectangular wall portion that protrudes upward (in the Z-axis positive direction) from the edges of the spacer body 511 in the X-axis positive direction, X-axis negative direction, and Y-axis positive direction. The first wall portion 512 is positioned to cover approximately half of the pair of short sides 411b and the bottom surface 411c of the container 410 of the energy storage element 400 in the Z-axis direction.

[0079] The second wall portion 513 is a flat, rectangular wall portion that protrudes upward (in the Z-axis positive direction) from the X-axis positive end of the Y-axis negative edge of the spacer body 511. The second wall portion 513 is positioned to cover approximately half of the X-axis positive end of the container lid 412 of the energy storage element 400 in the Z-axis direction. Specifically, the second wall portion 513 faces the wall surface of the container lid 412 between the gas discharge valve 412a of the energy storage element 400 and the X-axis positive electrode terminal 420, and is positioned to cover approximately half of this wall surface in the Z-axis direction.

[0080] The first ends 514 and 515 are flat, rectangular wall portions that project upward (in the positive Z-axis direction) from the X-axis negative end of the Y-axis negative edge of the spacer body 511. The first ends 514 and 515 are positioned to cover approximately half of the X-axis negative end of the container lid 412 of the energy storage element 400 in the Z-axis direction. Specifically, the first ends 514 and 515 face the wall surface of the container lid 412 between the gas discharge valve 412a of the energy storage element 400 and the X-axis negative electrode terminal 420, and are positioned to cover approximately half of this wall surface in the Z-axis direction. The second end 516 is positioned between the first ends 514 and 515.

[0081] The second end 516 is a recess that is recessed downward (in the negative Z-axis direction) from the first ends 514 and 515, and is lower in height than the first ends 514 and 515. The second end 516 is a rectangular recess when viewed from the Y-axis direction. The first ends 514 and 515 are wall portions adjacent to the second end 516 at the ends in the intersecting direction (Y-axis direction) that intersects the vertical direction of the spacer body 511. In this embodiment, the first end 514 is positioned in the positive X-axis direction of the second end 516, and the first end 515 is positioned in the negative X-axis direction of the second end 516. Thus, the first ends 514 and 515 are a pair of wall portions positioned on both sides of the second end 516 in the X-axis direction, and the second end 516 is a recess that is recessed in the negative Z-axis direction and positioned between the first ends 514 and 515. In other words, the second end 516 is the space formed between the first end 514 and 515, which are spaced apart in the X-axis direction.

[0082] The protruding portion 517 protrudes downward (in the negative Z-axis direction) from the second end portion 516 and is a part that guides the liquid passing through the second end portion 516 downward. The protruding portion 517 is a guide portion that guides the liquid passing through the second end portion 516 downward. The liquid is, for example, electrolyte that has leaked from the energy storage element 400 and accumulated on the spacer body 511, or condensed water that has formed on the spacer body 511. Specifically, the protruding portion 517 is a plate-shaped and rectangular part that is positioned in the negative Z-axis direction of the second end portion 516 on the side surface of the spacer body 511 in the negative Y-axis direction and extends in the negative Z-axis direction. The protruding portion 517 has a first groove portion 517a.

[0083] The first groove 517a is a groove on the surface of the projection 517 that is recessed in the direction of the intersection (Y-axis direction) and extends in the vertical direction (Z-axis direction). In this embodiment, the first groove 517a is a recess in which the center of the X-axis direction of the Y-axis-negative surface of the projection 517 is recessed in a rectangular shape in the Y-axis-positive direction. In the Z-axis direction, the first groove 517a extends from one end edge to the other end edge of the projection 517, but the Z-axis-positive end of the first groove 517a is positioned lower than the adjacent part of the projection 517 in the X-axis direction. In this embodiment, the Z-axis-positive end of the first groove 517a is connected to the second groove 511a. The Z-positive end of the first groove 517a is positioned in the Z-negative direction relative to the Z-positive end face of the spacer projection 511b and the Z-positive surface of the spacer body 511 located around the spacer projection 511b.

[0084] As described above, the intermediate spacer 510 is positioned between the two energy storage elements 400 in the Z-axis direction. As shown in Figure 6, the intermediate spacer 510 is positioned below energy storage element 400 (energy storage element 400a), and the other energy storage element 400 (energy storage element 400b) is positioned below the intermediate spacer 510. The protrusion 517 is positioned to protrude lower than the other energy storage element 400 (energy storage element 400b).

[0085] In this embodiment, the first outer casing 110 has an outer casing projection 116 that protrudes upward from the main surface 110a, which is the surface in the positive Z-axis direction (upper surface), and an end spacer 520 is positioned above the outer casing projection 116. An energy storage element 400b is positioned above the end spacer 520, and an intermediate spacer 510 is positioned above the energy storage element 400b. The projection 517 protrudes in the direction of the energy storage element 400b and extends beyond the energy storage element 400b and the end spacer 520 to above the main surface 110a and below the end spacer 520. Similarly, the first groove 517a extends above the main surface 110a and below the energy storage element 400b and the end spacer 520.

[0086] [4. Explanation of Effects] As described above, according to the energy storage device 1 according to an embodiment of the present invention, the intermediate spacer 510 below the energy storage element 400a has a second end 516 that is lower in height than adjacent first ends 514 and 515 in the intersecting direction that intersects with the vertical direction of the spacer body 511. The intermediate spacer 510 has a projection 517 that protrudes downward from the second end 516 and guides the liquid passing through the second end 516 downward. In this way, by providing the intermediate spacer 510 with a projection 517 that protrudes downward from the second end 516, liquid such as electrolyte or condensed water accumulated in the intermediate spacer 510 can be guided downward from the second end 516 by the projection 517 and discharged. This makes it possible to suppress the energy storage element 400a from short-circuiting with a conductive member below (such as the energy storage element 400b) due to the liquid.

[0087] In the intermediate spacer 510, the protrusion 517 has a first groove 517a, which acts as a liquid flow path, and the liquid easily flows down through the first groove 517a. Therefore, when the liquid accumulated in the intermediate spacer 510 is discharged downward by the protrusion 517, it can be easily guided downward and discharged.

[0088] By allowing the liquid to flow into the first groove 517a, the liquid can be retained within the first groove 517a, preventing it from falling from the second end 516. The spacer body 511 is also provided with a spacer projection 511b, which allows the liquid to be contained in the area of ​​the spacer body 511 where the spacer projection 511b is not provided, preventing it from falling from the second end 516. The Z-axis positive end face (upper surface) of the spacer projection 511b is positioned further in the Z-axis positive direction than the Z-axis positive end of the first groove 517a. Therefore, even if the liquid contained in the area of ​​the spacer body 511 where the spacer projection 511b is not provided overflows, the liquid can be discharged from the first groove 517a before it reaches the upper surface of the spacer projection 511b. This prevents the energy storage element 400a above the intermediate spacer 510 from being immersed in the liquid.

[0089] Since the protrusion 517 is positioned to protrude below the energy storage element 400b below the intermediate spacer 510, when the liquid accumulated in the intermediate spacer 510 is discharged downward by the protrusion 517, the liquid is discharged below the energy storage element 400b. This prevents the liquid from short-circuiting the energy storage element 400a with the energy storage element 400b below it.

[0090] Since the energy storage element 400b is positioned higher than the main surface 110a of the first outer casing 110 by the outer casing protrusion 116, the liquid accumulates below the energy storage element 400b. This prevents the liquid from coming into contact with the energy storage element 400b even if it accumulates on the first outer casing 110.

[0091] Since the first ends 514 and 515 are wall portions and the second end 516 is a recess that is recessed from the wall portion, the liquid accumulated in the intermediate spacer 510 is prevented from falling from the first ends 514 and 515 and is more likely to fall from the second end 516. As a result, the liquid is prevented from falling from locations other than the protrusion 517 and is more easily discharged downward from the second end 516 by the protrusion 517.

[0092] Since the spacer body 511 is provided with a second groove 511a extending toward the second end 516, the second groove 511a acts as a liquid flow path, allowing the liquid accumulated on the spacer body 511 to be easily guided toward the second end 516. This allows the liquid to be easily discharged downward from the second end 516 by the protrusion 517.

[0093] [5 Explanation of variations] Although an embodiment of the present invention, the energy storage device 1, has been described above, the present invention is not limited to this embodiment. The embodiments disclosed herein are illustrative and not restrictive in all respects, and the scope of the present invention includes all modifications in the sense and scope equivalent to the claims.

[0094] In the above embodiment, the outer casing 100 is such that the second outer casing 120 is a bottomed rectangular cylindrical member with an opening formed on the Z-axis minus side, and the first outer casing 110 is a flat rectangular member that closes the opening of the second outer casing 120. However, the first outer casing 110 may be a bottomed rectangular cylindrical member with an opening formed on the Z-axis plus side, and the second outer casing 120 may be a flat rectangular lid that closes the opening of the first outer casing 110, or it may be any other shape.

[0095] In the above embodiment, the first outer casing 110 is positioned in the negative Z-axis direction of the energy storage element 400, and the restraining body 600 is positioned in the positive Z-axis direction of the energy storage element 400, and they are joined together. However, the first outer casing 110 may be positioned in the positive Z-axis direction of the energy storage element 400, and the restraining body 600 may be positioned in the negative Z-axis direction of the energy storage element 400, and they are joined together. In other words, the energy storage device 1 may have a configuration where the top and bottom are reversed. Even in this case, the intermediate spacer 510 has a protruding portion 517 that protrudes downward from the second end 516, which is lower in height than the first end 514 and 515.

[0096] In the above embodiment, the first outer casing 110 is fitted with a restraining body 600 to restrain the energy storage element 400. However, the first outer casing 110 may not have a restraining body 600 attached to it, and the restraining body 600 may be attached to another member to restrain the energy storage element 400.

[0097] In the above embodiment, the pair of wall portions of the first end portions 514 and 515 are arranged on both sides of the second end portion 516. However, if the second end portion 516 is located at the corner of the spacer body 511, the first end portion 514 or 515 may be arranged on only one side of the second end portion 516.

[0098] In the above embodiment, the second end portion 516 is lower in height than the adjacent portions (first end portions 514 and 515) because the wall portion at the end of the spacer body 511 is recessed downwards. However, the second end portion 516 only needs to be lower in height than the adjacent portions of the spacer body 511, and it is also possible that the upper surface of the spacer body 511 is inclined so that it is lower in height than the adjacent portions (first end portions).

[0099] In the above embodiment, the first groove 517a of the protrusion 517 is a recess in which the central part in the X-axis direction of the Y-axis-negative plane of the protrusion 517 is recessed in a rectangular shape. However, the first groove 517a may be recessed in any shape other than rectangular, as long as it can guide the liquid passing through the second end 516 downwards, and may be located at any position on the protrusion 517.

[0100] In the above embodiment, the protruding portion 517 is a plate-shaped and rectangular portion in which the first groove 517a is formed. However, the protruding portion 517 can be any shape, such as columnar or cylindrical, as long as it can guide the liquid passing through the second end portion 516 downwards, and does not need to have the first groove 517a.

[0101] In the above embodiment, the protrusion 517 (and the first groove 517a) extends below the energy storage element 400b and the end spacer 520. However, the protrusion 517 (and the first groove 517a) does not have to extend below the end spacer 520, nor does it have to extend below the energy storage element 400b. A conductive member other than the energy storage element 400 may be placed below the intermediate spacer 510.

[0102] In the above embodiment, the second groove 511a of the spacer body 511 is a groove that extends in the X-axis direction toward the second end 516 along the edge of the spacer body 511 in the negative Y-axis direction. However, the second groove 511a may be formed at any position on the spacer body 511, such as a groove that extends from the central part of the spacer body 511 or from the end in the X-axis direction toward the second end 516. In particular, by increasing the volume of the recessed portion of the first groove 517a, the liquid can be contained within the first groove 517a, and the liquid can be prevented from falling from the second end 516.

[0103] In the above embodiment, the spacer body 511 has a rectangular spacer protrusion 511b when viewed from above, but the shape of the spacer protrusion 511b is not particularly limited. In particular, by making the protruding area of ​​the spacer protrusion 511b smaller or increasing the amount of protrusion, a larger amount of liquid can be contained in the position of the spacer body 511 where the spacer protrusion 511b is not provided, thereby suppressing the liquid from falling from the second end 516. The spacer body 511 may be formed so that one or both of the second groove 511a and the spacer protrusion 511b can contain a larger amount of liquid than the total amount of electrolyte contained in the energy storage element 400, or the excess amount of electrolyte. The spacer body 511 does not have to have at least one of the second groove 511a and the spacer protrusion 511b.

[0104] In the above embodiment, all intermediate spacers 510 are assumed to have the above configuration, but any of the intermediate spacers 510 may have a different configuration. The end spacers 520 may also have a configuration similar to that of the intermediate spacers 510, such as having protruding parts.

[0105] The energy storage device 1 does not need to have all of the above-mentioned components. The energy storage device 1 does not need to have the control unit 20, the outer casing 100, the first reinforcing member 200, or the restraining body 600, etc.

[0106] The present invention also includes forms constructed by arbitrarily combining the components included in the above embodiments and their modified examples.

[0107] The present invention can be implemented not only as an energy storage device 1, but also as an intermediate spacer 510. [Industrial applicability]

[0108] This invention can be applied to energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries. [Explanation of Symbols]

[0109] 1. Energy storage device 10 Energy storage units 20 Control Units 21, 22 External terminals 800, 810, 820, 830 busbar 100 Exterior 110 First exterior body 110a main surface 116 Outer body protrusion 120 Second exterior body 130 Fixing member 400, 400a, 400b energy storage elements 410 Container 411 Container body 411a long side 420 Electrode terminal 500 Spacer 510 Intermediate Spacer 511 Spacer body 511a Second groove 511b Spacer protrusion 512 First wall 513 Second wall section 514, 515 First end 516 Second end 517 Protrusion 517a First groove 520 End Spacer 600 Restraint body 900, 910, 920 Conductive components

Claims

1. An energy storage device comprising an energy storage element and a spacer disposed below the energy storage element, The previous spacer is The spacer body and The spacer body has a protruding portion that extends downward from a second end, which is lower in height than the adjacent first end, at the ends in the intersecting direction that intersects the vertical direction of the spacer body. The aforementioned protrusion extends further than the first end in the direction opposite to the spacer body in the intersecting direction. Furthermore, it includes a conductive member positioned below the spacer, The aforementioned protrusion is positioned so as not to overlap with the conductive member when viewed from above or below. Energy storage device.

2. An energy storage device comprising an energy storage element and a spacer disposed below the energy storage element, The previous spacer is The spacer body and The spacer body has a protruding portion that extends downward from a second end, which is lower in height than the adjacent first end, at the ends in the intersecting direction that intersects the vertical direction of the spacer body. The protruding portion has a first groove that is recessed in the intersecting direction and extends in the vertical direction, Furthermore, it includes a conductive member positioned below the spacer, The aforementioned protrusion is positioned so as not to overlap with the conductive member when viewed from above or below. Energy storage device.

3. The protruding portion is positioned to protrude below the conductive member. The energy storage device according to claim 1 or 2.

4. The conductive member is provided in another energy storage element located below the spacer, The aforementioned protrusion is positioned to protrude downwards compared to the other energy storage elements. The energy storage device according to claim 3.

5. The aforementioned first end is a wall portion that protrudes upward, The second end is a recess that is recessed downward from the wall portion. The energy storage device according to any one of claims 1 to 4.

6. The spacer body has a second groove which is a groove extending toward the second end. The energy storage device according to any one of claims 1 to 5.

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