Power storage device

Abstract

This power storage device comprises: a first power storage element and a second power storage element arrayed in a first direction; a bus bar connected to the first power storage element and the second power storage element; and a first wall part disposed on one side of the bus bar in a second direction orthogonal to the first direction. The first power storage element is provided with a first terminal on one side in a third direction orthogonal to the first direction and the second direction. The second power storage element is provided with a second terminal on the one side in the third direction. The bus bar is provided with a first connection part connected to the first terminal, a second connection part connected to the second terminal, and an intermediate part that is a part between the first connection part and the second connection part. The intermediate part is provided with a projection section projecting to one side in the second direction. The first wall part is provided with two first protruding portions protruding toward the bus bar, and the projection section is disposed between the two first protruding portions in the first direction.

Description

Power storage device

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

[0002] Patent Document 1 discloses a battery pack composed of a busbar module and a battery pack. The busbar module has a case made of insulating resin and busbars made of conductive metal. The case is integrally molded from insulating resin as the main body of the busbar module. The case has a long bottom plate formed in the direction in which the cells are arranged. A partition wall and a chamber side wall are formed in the bottom plate. The portion between the partition wall and the chamber side wall forms the busbar accommodating chamber. A busbar having a pair of bolt through holes is accommodated in the busbar accommodating chamber. Electrode bolts of adjacent cells arranged in the busbar accommodating chamber are inserted into each of the pair of bolt through holes of the busbar.

[0003] Japanese Patent Application Laid-Open No. 2019-29312

[0004] In the busbar module of the conventional battery pack, the partition wall and the side wall of the accommodation chamber formed on the bottom plate of the case face each other across the busbar and are positioned close to the busbar. Therefore, the partition wall and the side wall of the accommodation chamber may hinder the efficiency of the busbar placement work. On the other hand, if the partition wall and the side wall of the accommodation chamber are moved away from the busbar in order to solve this problem, the busbar may be more susceptible to movement or change in posture due to vibration or impact, which may result in malfunction of the busbar.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and has an object to provide a power storage device with a simple configuration and improved resistance to vibration or impact.

[0006] a first wall portion arranged on one side of the busbar in a second direction perpendicular to the first direction, wherein the first storage element has a first terminal on one side of the busbar in a third direction perpendicular to the first direction and the second direction, and the second storage element has a second terminal on the one side of the busbar in the third direction; the busbar has a first connection portion connected to the first terminal, a second connection portion connected to the second terminal, and an intermediate portion between the first connection portion and the second connection portion; the intermediate portion has a protruding portion protruding to the one side of the second direction; and the first wall portion has two first convex portions protruding toward the busbar, the protruding portion being arranged between the two first convex portions in the first direction.

[0007] According to the present invention, it is possible to provide an electricity storage device with improved resistance to vibrations or impacts with a simple configuration.

[0008] FIG. 1 is a perspective view showing the appearance of an energy storage device according to an embodiment. FIG. 2 is an exploded perspective view of an energy storage device according to an embodiment. FIG. 3 is a first perspective view showing a bus bar and its surrounding configuration according to an embodiment. FIG. 4 is a second perspective view showing a bus bar and its surrounding configuration according to an embodiment. FIG. 5 is a third perspective view showing a bus bar and its surrounding configuration according to an embodiment. FIG. 6 is a plan view showing a configuration of a bus bar accommodating portion according to an embodiment. FIG. 7 is a plan view showing a bus bar and its surrounding configuration according to an embodiment. FIG. 8 is a cross-sectional view simply showing a part of a cross section taken along line XIII-XIII in FIG. 7.

[0009] (1) An energy storage device according to one aspect of the present invention includes a first storage element and a second storage element aligned in a first direction, a bus bar connected to the first storage element and the second storage element, and a first wall portion arranged on one side of the bus bar in a second direction perpendicular to the first direction, wherein the first storage element includes a first terminal on one side in a third direction perpendicular to the first direction and the second direction, and the second storage element includes a second terminal on the one side in the third direction, the bus bar includes a first connection portion connected to the first terminal, a second connection portion connected to the second terminal, and an intermediate portion between the first connection portion and the second connection portion, the intermediate portion including a protruding portion protruding to the one side in the second direction, and the first wall portion including two first convex portions protruding toward the bus bar, the protruding portion being arranged between the two first convex portions in the first direction.

[0010] In an energy storage device according to one aspect of the present invention, the busbar has a middle portion including a protruding portion, and the protruding portion is disposed between two first protruding portions protruding from the first wall portion. Therefore, these two first protruding portions can suppress not only the movement of the busbar in the first direction but also the change in the busbar's posture when viewed from the third direction (rotation around an axis in the third direction). This suppresses stress generated in the busbar when the energy storage device is subjected to vibration or impact. As a result, the occurrence of malfunctions in the busbar is suppressed. Furthermore, it is possible to ensure a relatively large space between the busbar and the first wall portion other than the two first protruding portions. This allows for efficient arrangement of the busbar relative to the first and second energy storage elements. Thus, the energy storage device according to one aspect of the present invention is an energy storage device with improved resistance to vibration and impact with a simple configuration.

[0011] (2) The energy storage device described in (1) above may further include a second wall portion arranged on the other side of the bus bar in the second direction, and the second wall portion may include a second convex portion protruding toward the bus bar.

[0012] According to the energy storage device described in (2) above, the intermediate portion of the busbar is disposed between the first convex portion and the second convex portion in the second direction, which more reliably suppresses movement of the busbar in the first direction and changes in the posture of the busbar when viewed from the third direction (hereinafter also simply referred to as “changes in the posture of the busbar, etc.”).

[0013] (3) In the energy storage device described in (2) above, the second wall portion may have two second convex portions, and when viewed from the second direction, at least a portion of each of the two second convex portions may overlap with at least one of the two first convex portions.

[0014] According to the energy storage device described in (3) above, at least a portion of each of the two second convex portions is aligned with one of the two first convex portions in the second direction, thereby reliably suppressing changes in the posture of the bus bar, etc.

[0015] (4) The storage device described in (2) or (3) above may further include a connecting portion that connects the first convex portion and the second convex portion, the connecting portion being arranged on the other side of the intermediate portion in the third direction.

[0016] According to the energy storage device described in (4) above, the first and second protrusions are connected by the connecting portion disposed in the space behind the intermediate portion of the bus bar. Therefore, the connecting portion is unlikely to interfere with the arrangement of the bus bar, and the first and second protrusions are unlikely to deform. As a result, the first and second protrusions more reliably suppress changes in the posture of the bus bar.

[0017] (5) In the energy storage device described in any one of (1) to (4) above, each of the two first protrusions may include an opposing wall portion facing the bus bar and a connecting wall portion connecting the opposing wall portion and the first wall portion.

[0018] According to the energy storage device described in (5) above, the first convex portion includes an opposing wall portion and a connecting wall portion that face in different directions and are connected to each other, and therefore the first convex portion can be formed using a relatively small amount of material while ensuring rigidity for suppressing changes in the posture of the bus bar, etc.

[0019] 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). The embodiments described below are all 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 merely examples and are not intended to limit the present invention. In each drawing, dimensions are not strictly illustrated, and may be appropriately emphasized, omitted, or simplified. In each drawing, the same or similar components are designated by the same reference numerals.

[0020] In the following description and drawings, the arrangement direction of multiple energy storage elements or the direction in which the long sides of the container of one energy storage element face each other is defined as the Y-axis direction. The arrangement direction of a pair of terminals (positive and negative) in one energy storage element or the direction in which the short sides of the container of one energy storage element face each other is defined as the X-axis direction. The arrangement direction of the container body and cover plate of the energy storage element is defined as the Z-axis direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect each other (orthogonal in this embodiment). Depending on the usage mode, the Z-axis direction may not be the up-down direction, but for convenience of explanation, the following description will be made assuming that the Z-axis direction is the up-down direction.

[0021] In the following description, the positive X-axis direction refers to the direction of the arrow on the X-axis, 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 direction and the Z-axis direction. Expressions indicating relative directions or attitudes, such as parallel and orthogonal, also include cases where the directions or attitudes are not strictly speaking the same. Two directions being parallel 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 about a few percent. In the following description, when the term "insulation" is used, it means "electrical insulation". An insulating material has a volume resistivity of 1 x 10 １０ It is preferable that the material be made of a material with a resistance of Ωm or more.

[0022] (Embodiment) [1. General Description of Energy Storage Device 10] Fig. 1 is a perspective view showing the appearance of an energy storage device 10 according to an embodiment. Fig. 2 is an exploded perspective view of the energy storage device 10 according to an embodiment. In Fig. 2, the nut 700 coupled to the shaft portion 23 of the terminal 22 of the energy storage element 20 is not shown.

[0023] The power storage device 10 is a device capable of charging with electricity from an external source and discharging electricity to an external source. In this embodiment, the power storage device 10 has a substantially rectangular parallelepiped shape. The rectangular parallelepiped here refers to a hexahedron with all sides formed as rectangles or squares. The power storage device 10 is a battery module (battery assembly) used for power storage, power supply, or other purposes. Specifically, the power storage device 10 is used as a battery for driving or starting the engine of a moving object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, automatic guided vehicle (AGV), 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.

[0024] 1 and 2 , the energy storage device 10 includes an energy storage unit 30, a pair of end members 400, a bus bar frame 300, a plurality of bus bars 340, and a wiring unit 390. The energy storage unit 30 includes a plurality of energy storage elements 20 and a plurality of spacers 100 and 150.

[0025] In addition to the above components, the energy storage device 10 may also include an exterior body that houses the above components, and electrical equipment such as a circuit board, fuse, relay, etc. that monitors or controls the charging and discharging states of the energy storage elements 20.

[0026] The energy storage elements 20 are secondary batteries (single cells), and more specifically, non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries. The energy storage elements 20 have a flattened rectangular parallelepiped (square) shape. In this embodiment, twelve energy storage elements 20 are arranged side by side in the Y-axis direction. The Y-axis direction is an example of a first direction.

[0027] There are no limitations on the size, shape, or number of the storage elements 20 to be arranged. The storage elements 20 may have a cylindrical shape, an elongated cylindrical shape, an elliptical cylindrical shape, or the like. The number of storage elements 20 may be two or more. The storage elements 20 are not limited to non-aqueous electrolyte secondary batteries, and may be secondary batteries other than non-aqueous electrolyte secondary batteries, or may be capacitors. The storage elements 20 may be primary batteries instead of secondary batteries. The storage elements 20 may be batteries using a solid electrolyte. The storage elements 20 may be pouch-type storage elements.

[0028] As shown in FIG. 2 , the energy storage element 20 includes a container 21 and a pair of (positive and negative) terminals 22. The container 21 contains an electrode assembly, a pair of current collectors, an electrolyte (non-aqueous electrolyte), and the like, but these are not shown. The type of electrolyte is not particularly limited as long as it does not impair the performance of the energy storage element 20, and various types can be selected. In addition to the above components, the energy storage element 20 may also include spacers arranged on the sides or below the electrode assembly, an insulating film that wraps around the electrode assembly, and the like. An insulating film that covers the outer surface of the container 21 may be arranged around the container 21.

[0029] The container 21 has a container body with an opening formed therein and a cover plate that closes the opening of the container body. After the electrode assembly and the like are housed inside the container body, the container body and the cover plate are joined by welding or the like, thereby sealing the inside of the container 21. The container 21 is made of a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet. Resin may also be used as the material for the container 21.

[0030] The container 21 has a pair of opposing long sides 21a, a pair of opposing short sides 21b, and a terminal placement surface 21c adjacent to the long sides 21a and the short sides 21b. The long sides 21a are rectangular flat surfaces adjacent to the short sides 21b and the terminal placement surface 21c and have a larger area than the short sides 21b. The short sides 21b are rectangular flat surfaces adjacent to the long sides 21a and the terminal placement surface 21c and have a smaller area than the long sides 21a. The terminal placement surface 21c is a surface on which a pair of terminals 22 are arranged and is formed by the upper surface of the lid plate of the container 21 in this embodiment. The container 21 may also be provided with other elements such as a gas release valve and a liquid injection unit for injecting electrolyte into the container 21.

[0031] The terminal 22 is a member electrically connected to the electrode assembly housed in the container 21. One of the pair of terminals 22 is electrically connected to the positive electrode of the electrode assembly, and the other is electrically connected to the negative electrode of the electrode assembly. In this embodiment, the terminal 22 is provided with a shaft portion 23 that protrudes in the positive direction of the Z axis and has a thread on its outer periphery. The bus bar 340 is fixed to the terminal 22 by a nut 700 (see FIG. 1 ) that is coupled to the shaft portion 23. This electrically and mechanically connects the bus bar 340 to the terminal 22.

[0032] The electrode assembly is an energy storage element (power generating element) formed by stacking a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is an electrode plate in which a positive electrode active material layer is formed on a current collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is an electrode plate in which a negative electrode active material layer is formed on a current collector foil made of a metal such as copper or a copper alloy. Any known material capable of absorbing and releasing charge-transporting ions can be used as the active material used in the positive electrode active material layer and the negative electrode active material layer. The separator can be a microporous resin sheet, nonwoven fabric, or the like. In this embodiment, a wound electrode assembly formed by winding electrode plates (positive electrode plate and negative electrode plate) is used as the electrode assembly included in the energy storage element 20. The electrode assembly included in the energy storage element 20 may be of any shape, such as 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-like shape.

[0033] In this embodiment, twelve energy storage elements 20 are connected in series by eleven bus bars 340. In an energy storage unit 30 including twelve energy storage elements 20, the positive electrode terminal 22 of the energy storage element 20 located at the end in the negative direction of the Y axis functions as the total positive terminal 22a of the energy storage unit 30. The negative electrode terminal 22 of the energy storage element 20 located at the end in the positive direction of the Y axis of the energy storage unit 30 functions as the total negative terminal 22b of the energy storage unit 30. The electrical connection mode of the twelve energy storage elements 20 is not limited to this, and any combination of series and parallel connections may be used. Six energy storage element 20 groups, each consisting of two energy storage elements 20 connected in parallel, may be arranged in the Y axis direction, and these six energy storage element 20 groups may be connected in series.

[0034] The spacers 100 and 150 are plate-shaped members that are disposed adjacent to the energy storage elements 20 and insulate the energy storage elements 20 from other members. More specifically, the spacer 150 is an inter-cell spacer that is disposed between two energy storage elements 20 adjacent to each other in the Y-axis direction and insulates one of the two energy storage elements 20 from the other. The spacer 100 is an end spacer that is disposed between an energy storage element 20 at the end of the energy storage unit 30 in the Y-axis direction and an end member 400 and insulates the energy storage element 20 from the end member 400. In this embodiment, the spacers 100 and 150 each also function as a cell holder that holds the energy storage elements 20.

[0035] In the present embodiment, eleven spacers 150 and a pair of two spacers 100 are arranged corresponding to the twelve energy storage elements 20. The number of spacers 100 and 150 may be changed as appropriate depending on the number of energy storage elements 20 included in the energy storage device 10, etc. The spacers 100 and 150 are 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), polyamide (PA), ABS resin, or a composite material thereof, or a metal with an insulating coating.

[0036] Each of the pair of end members 400 serves to restrain the energy storage unit 30 in the Y-axis direction, which is the arrangement direction of the energy storage elements 20. Specifically, the pair of end members 400 are connected by side plates (not shown) located on both sides of the energy storage unit 30 in the X-axis direction, sandwiching the energy storage unit 30 therebetween, thereby restraining the energy storage unit 30 from both sides in the Y-axis direction. The end members 400 are formed of metal members such as steel or stainless steel to ensure strength. The material for forming the end members 400 is not particularly limited, and they may be formed of a high-strength insulating material. The surface of the metal end members 400 may be subjected to an insulating treatment such as a resin coating. The shape of the end members 400 is also not particularly limited. The X-axis direction is an example of a second direction perpendicular to the first direction. The negative X-axis direction is an example of one side of the second direction, and the positive X-axis direction is an example of the other side of the second direction. The energy storage device 10 does not necessarily have to include a pair of end members 400. When the energy storage unit 30 is housed in an exterior body, the exterior body may play a role in restricting the position of the plurality of energy storage elements 20 included in the energy storage unit 30 or restraining them in the Y-axis direction.

[0037] The bus bar frame 300 is an insulating member made of an insulating material such as resin. The bus bar frame 300 may be made of a resin such as PP, PE, PS, or PPS, which is used for the spacers 100 and 150 described above, or a metal coated with an insulating coating. The bus bar frame 300 has a plurality of bus bar accommodating portions 301, each of which accommodates a bus bar 340. In this embodiment, the bus bar frame 300 also functions as a member that supports the wiring unit 390 from below. The bus bar frame 300 is fixed to the energy storage unit 30 by being connected to one or more spacers 100 or 150. If the energy storage device 10 includes an exterior body that accommodates the energy storage unit 30, the bus bar frame 300 may be fixed to the exterior body.

[0038] The bus bar frame 300 according to this embodiment has a structure that can suppress movement of the bus bar 340 and change in its posture when viewed from the positive direction of the Z axis (hereinafter also referred to as a plan view). Details of the structure around the bus bar 340 in the bus bar frame 300 will be described later using Figures 3 to 8. The Z axis direction is an example of a third direction that is perpendicular to the first direction and the second direction. The positive Z axis direction is an example of one side of the third direction, and the negative Z axis direction is an example of the other side of the third direction.

[0039] The wiring unit 390 is a group of components for measuring the voltages of the multiple energy storage elements 20. Specifically, the wiring unit 390 includes multiple detection terminals 350, a connector 391, and multiple electric wires 380 connecting the multiple detection terminals 350 and the connector 391. Each of the multiple detection terminals 350 is fixed to the terminal 22 of the energy storage element 20 by a nut 700, together with the bus bar 340 corresponding to the detection terminal 350. A detection terminal 350 is also fixed to each of the total positive terminal 22a and the total negative terminal 22b (see FIG. 2 ) of the energy storage unit 30, together with a conductive member such as a bus bar (not shown). The bus bar frame 300 is provided with fixing portions for fixing each of the multiple detection terminals 350. A control device that controls charging and discharging of the energy storage device 10 is connected to the connector 391. The control device detects the potentials of the bus bars 340, the total positive terminal 22a, and the total negative terminal 22b via the detection terminals 350 and the electric wires 380. This allows the control device to detect the voltage of each of the storage elements 20.

[0040] [3. Regarding the Bus Bar 340 and Its Surrounding Structure] The energy storage device 10 according to this embodiment includes an energy storage unit 30 including a plurality of energy storage elements 20 arranged in the Y-axis direction as described above. The energy storage unit 30 is restrained in the Y-axis direction by a pair of end members 400. Therefore, the movement of each of the plurality of energy storage elements 20 in the Y-axis direction is restricted by the pair of end members 400. However, the movement of each of the plurality of energy storage elements 20 in the X-axis direction is less restricted by the pair of end members 400. Therefore, due to vibration or impact applied to the energy storage device 10, one of two energy storage elements 20 adjacent in the Y-axis direction may move in the X-axis direction relative to the other. If one of the energy storage elements 20 moves by a large amount, a relatively large stress is generated in the bus bar 340 connecting the two energy storage elements 20, which may cause a defect such as deformation of the bus bar 340.

[0041] Therefore, the energy storage device 10 according to this embodiment has a configuration for suppressing movement and changes in posture of the bus bar 340. The configuration of the bus bar 340 and its surroundings will be described below with reference to Figures 3 to 8. The configuration of one bus bar 340 and its surroundings described below can be adopted as the configuration of all bus bars 340 and their surroundings included in the energy storage device 10.

[0042] FIG. 3 is a first perspective view showing a bus bar 340 and its surrounding configuration according to the embodiment. FIG. 4 is a second perspective view showing a bus bar 340 and its surrounding configuration according to the embodiment. FIG. 5 is a third perspective view showing a bus bar 340 and its surrounding configuration according to the embodiment. FIG. 6 is a plan view showing a bus bar accommodating portion 301 according to the embodiment. FIG. 7 is a plan view showing a bus bar 340 and its surrounding configuration according to the embodiment. FIG. 8 is a cross-sectional view simply showing a portion of a cross section taken along line XIII-XIII in FIG. 7. In FIGS. 3 to 5 and 7, attention is focused on one bus bar 340 and two energy storage elements 20 to which the bus bar 340 is connected, and other bus bars 340 and energy storage elements 20 are omitted from illustration. In FIGS. 3 to 5, a wiring unit 390 and a plurality of spacers 150 included in the energy storage unit 30 are omitted from illustration.

[0043] 3 to 5 , in the energy storage device 10 according to this embodiment, two energy storage elements 20 aligned in the Y-axis direction are connected by a bus bar 340. In the following, in order to distinguish between the two energy storage elements 20, one of the two energy storage elements 20 will be referred to as a first energy storage element 20A, and the other will be referred to as a second energy storage element 20B. The terminal 22 included in the first energy storage element 20A will be referred to as a first terminal 22A, and the terminal 22 included in the second energy storage element 20B will be referred to as a second terminal 22B. The first terminal 22A and the second terminal 22B are aligned in the Y-axis direction. One of the first terminal 22A and the second terminal 22B is a positive terminal, and the other is a negative terminal.

[0044] The bus bar 340 is a plate-shaped member made of a metal such as aluminum or an aluminum alloy. The bus bar 340 includes a first connecting portion 341, a second connecting portion 342, and an intermediate portion 345. The first connecting portion 341 is connected to the first terminal 22A, and the second connecting portion 342 is connected to the second terminal 22B. Specifically, as shown in FIG. 3 , the first connecting portion 341 has a through hole 341a. The shaft portion 23 of the first terminal 22A is disposed to pass through the through hole 341a, and a nut 700 is coupled to the shaft portion 23. This connects the first connecting portion 341 to the first terminal 22A. The second connecting portion 342 has a through hole 342a. The shaft portion 23 of the second terminal 22B is disposed to pass through the through hole 342a, and a nut 700 is coupled to the shaft portion 23. This connects the second connecting portion 342 to the second terminal 22B.

[0045] More specifically, the busbar 340 is accommodated in a busbar accommodating portion 301 provided in the busbar frame 300. The busbar accommodating portion 301 is open on both sides in the Z-axis direction and forms a space surrounded by the Y-axis direction and the X-axis direction. Specifically, the busbar accommodating portion 301 is formed by a first wall portion 310 and a second wall portion 320 that face each other in the X-axis direction, and a pair of side wall portions 335 that face each other in the Y-axis direction. As shown in FIGS. 3 , 4 , and 6 , a first claw portion 319 is disposed on the first wall portion 310, and as shown in FIGS. 5 and 6 , a second claw portion 329 is disposed on the second wall portion 320. At least a portion of each of the first claw portion 319 and the second claw portion 329 is disposed in the positive direction of the Z-axis of the busbar 340. This restricts movement of the busbar 340 in the positive direction of the Z-axis before the busbar 340 accommodated in the busbar accommodating portion 301 is fixed to the terminal 22 by the nut 700.

[0046] The intermediate portion 345 of the bus bar 340 is a portion between the first connecting portion 341 and the second connecting portion 342. In this embodiment, as shown in Fig. 3 , the intermediate portion 345 has a shape that is curved in the positive direction of the Z axis. This allows the intermediate portion 345 to efficiently absorb displacement of one of the first connecting portion 341 and the second connecting portion 342 in the Z axis direction relative to the other.

[0047] 3 to 5, 7, and 8, the intermediate portion 345 according to this embodiment includes a protruding portion 346 that protrudes in the negative X-axis direction. The protruding portion 346 functions as a portion that suppresses changes in the posture of the bus bar 340. Specifically, the first wall portion 310, which is disposed in the negative X-axis direction of the bus bar 340, includes two first convex portions 311 that protrude toward the bus bar 340. In this embodiment, the first wall portion 310 is provided in the energy storage device 10 as a portion that is integral with the bus bar frame 300.

[0048] 3 to 7 , the two first convex portions 311 are arranged at a distance in the Y-axis direction on the first wall portion 310 extending in the Y-axis direction. The protrusion 346 of the bus bar 340 is arranged between the two first convex portions 311 arranged at a distance in the Y-axis direction. In other words, when the bus bar 340 is connected to the first energy storage element 20A and the second energy storage element 20B, the protrusion 346 of the intermediate portion 345 of the bus bar 340 is inserted between the two first convex portions 311.

[0049] That is, the energy storage device 10 according to the present embodiment includes a first energy storage element 20A and a second energy storage element 20B aligned in the Y-axis direction, a bus bar 340 connected to the first energy storage element 20A and the second energy storage element 20B, and a first wall portion 310 arranged on one side of the bus bar 340 in the X-axis direction, which is perpendicular to the Y-axis direction. The first energy storage element 20A includes a first terminal 22A on one side in the Z-axis direction, which is perpendicular to the Y-axis direction and the X-axis direction. The second energy storage element 20B includes a second terminal 22B on the same side in the Z-axis direction. The bus bar 340 includes a first connection portion 341 connected to the first terminal 22A, a second connection portion 342 connected to the second terminal 22B, and an intermediate portion 345 between the first connection portion 341 and the second connection portion 342. The intermediate portion 345 includes a protrusion 346 protruding on one side in the X-axis direction. The first wall portion 310 includes two first protrusions 311 that protrude toward the bus bar 340. The protrusion 346 is disposed between the two first protrusions 311 in the Y-axis direction.

[0050] As described above, in the energy storage device 10 according to the present embodiment, the intermediate portion 345 of the bus bar 340 includes a protruding portion 346, and the protruding portion 346 is disposed between the two first convex portions 311 protruding from the first wall portion 310. Therefore, these two first convex portions 311 can suppress not only the movement of the bus bar 340 in the Y-axis direction but also the change in the posture of the bus bar 340 when viewed from the Z-axis direction (rotation around the Z-axis). This can suppress stress generated in the bus bar 340 when the energy storage device 10 is subjected to vibration or impact. As a result, the occurrence of defects in the bus bar 340 is suppressed. As shown in FIGS. 4 and 7 , a relatively large space can be secured between the bus bar 340 and the first wall portion 310 in a portion other than the two first convex portions 311. Therefore, when the bus bar 340 is positioned in the positive direction of the X-axis of the first wall portion 310, the bus bar 340 and a jig or the like that holds the bus bar 340 are less likely to interfere with the first wall portion 310. Therefore, the bus bars 340 can be efficiently arranged relative to the first energy storage elements 20A and the second energy storage elements 20B.

[0051] Thus, the power storage device 10 according to this embodiment is a power storage device with a simple configuration and improved resistance to vibrations or impacts.

[0052] By contacting the inner surface of the first wall portion 310, which is the surface facing the positive X-axis direction, with the bus bar 340, it is possible to suppress changes in the posture of the bus bar 340. However, in this case, when arranging the bus bar 340 relative to the first energy storage element 20A and the second energy storage element 20B, interference between the first wall portion 310 and the bus bar 340 may prevent efficient arrangement. Considering variations in the arrangement positions of the first energy storage element 20A and the second energy storage element 20B and dimensional tolerances of the bus bar frame 300, it is difficult to accurately bring the inner surface of the first wall portion 310, which extends in the Y-axis direction, into contact with the edge of the bus bar 340, which extends in the Y-axis direction. As a result, the first wall portion 310 may be separated from the entire bus bar 340, or the presence of the first wall portion 310 may prevent the bus bar 340 from being connected to the first energy storage element 20A and the second energy storage element 20B. In this regard, in the energy storage device 10 according to the present embodiment, the first wall portion 310 is disposed at a position spaced apart from the bus bar 340 in the X-axis direction, and two first convex portions 311 that protrude from the first wall portion 310 toward the bus bar 340 are provided on the first wall portion 310. A protruding portion 346 that is inserted between the two first convex portions 311 is provided on an intermediate portion 345 of the bus bar 340. That is, in the energy storage device 10, a change in the posture of the bus bar 340 is not suppressed by an inner surface formed by the first wall portion 310 that extends in the Y-axis direction, but rather a structure is employed in which two portions (two first convex portions 311) that protrude from only a portion of the first wall portion 310 in the Y-axis direction suppress a change in the posture of the bus bar 340. This achieves both the prevention of the first wall portion 310 interfering with the placement of the bus bar 340 and the prevention of a change in the posture of the bus bar 340.

[0053] More specifically, the ratio of the width of the protrusion 346 in the Y-axis direction to the distance between the two first convex portions 311 in the Y-axis direction is 80% or more and 100% or less. That is, each of the two first convex portions 311 is disposed in contact with the protrusion 346 or in the vicinity of the protrusion 346. Therefore, the two first convex portions 311 can suppress movement of the protrusion 346 in the X-axis direction and can suppress rotation of the protrusion 346 in the XY plane about an axis parallel to the Z axis. As a result, movement of the bus bar 340 integrally including the protrusion 346 in the X-axis direction can be suppressed, and rotation of the bus bar 340 in the XY plane about an axis parallel to the Z axis can be suppressed.

[0054] In the present embodiment, the protrusion 346 only needs to have the function of suppressing changes in the posture of the bus bar 340 by coming into contact with the first convex portion 311. Therefore, it is not necessary to connect a conductive member such as the detection terminal 350 to the protrusion 346. Therefore, it is not necessary to provide the first wall portion 310 and the two first convex portions 311 with a hole, groove, recess, opening, or the like for arranging a conductive member electrically connected to the protrusion 346.

[0055] The bus bar 340 may be provided with only one protrusion 346. Therefore, compared to a structure in which two protrusions 346 are provided on the bus bar 340 and a convex portion protruding from the first wall portion 310 toward the bus bar 340 is inserted between the two protrusions 346, an increase in the weight of the metal bus bar 340 is suppressed. As a result, an increase in the weight of the energy storage device 10 including multiple bus bars 340 is suppressed. This becomes more noticeable as the number of bus bars 340 included in the energy storage device 10 increases.

[0056] During normal use, each of the two first convex portions 311 may or may not be in contact with the bus bar 340. Even when one first convex portion 311 is not in contact with the bus bar 340, as long as the distance between the first convex portion 311 and the bus bar 340 is within several millimeters, the first convex portion 311 can function as a portion that suppresses the movement or change in posture of the bus bar 340 when the bus bar 340 attempts to move or change its posture.

[0057] Each first protrusion 311 according to the present embodiment includes two walls facing in directions intersecting each other. Specifically, as shown in FIGS. 3 , 6 , and 7 , each of the two first protrusions 311 includes an opposing wall 312 that faces the bus bar 340 and a connecting wall 313 that connects the opposing wall 312 and the first wall 310. More specifically, in the present embodiment, the opposing wall 312 of the first protrusion 311 that is located in the positive direction of the Y axis extends from the connecting wall 313 in the positive direction of the Y axis (see FIGS. 6 and 8 ). The opposing wall 312 of the first protrusion 311 that is located in the negative direction of the Y axis extends from the connecting wall 313 in the negative direction of the Y axis (see FIGS. 6 and 8 ).

[0058] As described above, the first convex portion 311 includes the opposing wall portion 312 and the connecting wall portion 313 that face in different directions and are connected to each other. Therefore, the first convex portion 311 can be formed with a relatively small amount of material while ensuring the rigidity required to suppress movement of the bus bar 340. In other words, even if the thicknesses of the opposing wall portion 312 and the connecting wall portion 313 are relatively small (approximately 1 mm), the first convex portion 311 can ensure sufficient rigidity to suppress changes in the posture of the bus bar 340 because the opposing wall portion 312 facing the X-axis direction and the connecting wall portion 313 facing the Y-axis direction are combined. Compared to when the first convex portion 311 is a solid portion with a rectangular parallelepiped shape, the first convex portion 311, which is composed of the opposing wall portion 312 and the connecting wall portion 313, is more likely to deform. Therefore, the two first protrusions 311 can absorb the dimensional tolerance of the two first protrusions 311 and / or the bus bar 340 while suppressing movement and changes in posture of the protrusions 346 of the bus bar 340 .

[0059] In the present embodiment, the bus bar 340 is disposed between a first wall portion 310 and a second wall portion 320 that face each other in the X-axis direction. That is, as shown in FIGS. 5 to 8 , the energy storage device 10 according to the present embodiment includes a second wall portion 320 that is disposed on the other side of the bus bar 340 in the X-axis direction (in the present embodiment, the positive direction of the X-axis). The second wall portion 320 includes a second protrusion 321 that protrudes toward the bus bar 340. In the present embodiment, the second wall portion 320 is provided in the energy storage device 10 as a portion that is integral with the bus bar frame 300.

[0060] According to this configuration, the middle portion 345 of the bus bar 340 is disposed between the first convex portion 311 and the second convex portion 321 in the X-axis direction. This more reliably suppresses changes in the posture of the bus bar 340.

[0061] During normal use, each of the two second convex portions 321 may or may not be in contact with the bus bar 340. Even when one second convex portion 321 is not in contact with the bus bar 340, as long as the distance between the second convex portion 321 and the bus bar 340 is within several millimeters, the second convex portion 321 can function as a portion that suppresses the movement or change in posture of the bus bar 340 when the bus bar 340 attempts to move or change its posture.

[0062] More specifically, the second wall portion 320 includes two second protrusions 321. When viewed from the X-axis direction, at least a portion of each of the two second protrusions 321 overlaps with at least one of the two first protrusions 311.

[0063] According to this configuration, at least a portion of each of the two second convex portions 321 is aligned with one of the two first convex portions 311 in the X-axis direction, thereby reliably suppressing changes in the posture of the bus bar 340, etc.

[0064] As described above, the energy storage device 10 according to this embodiment includes the first convex portion 311 and the second convex portion 321, and as shown in Figures 6 and 8, includes a connecting portion 330 that connects the first convex portion 311 and the second convex portion 321. The connecting portion 330 is disposed on the other side of the intermediate portion 345 in the Z-axis direction (in the negative Z-axis direction in this embodiment).

[0065] According to this configuration, first convex portion 311 and second convex portion 321 are connected by connecting portion 330, which is disposed in the space behind intermediate portion 345 of bus bar 340. Therefore, connecting portion 330 is unlikely to interfere with the arrangement of bus bar 340, and first convex portion 311 and second convex portion 321 are unlikely to deform. As a result, first convex portion 311 and second convex portion 321 more reliably suppress changes in the posture of bus bar 340.

[0066] [3. Description of Modifications] While the energy storage device 10 according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. The embodiment disclosed herein is an example in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0067] The bus bars 340 and their peripheral configurations (see FIGS. 3 to 8) described in the embodiment may be adopted as the bus bars 340 and their peripheral configurations for only some of all the bus bars 340 included in the energy storage device 10. In other words, the bus bars 340 and their peripheral configurations do not all need to be identical.

[0068] In the embodiment, the first convex portion 311 and the second convex portion 321 are each provided integrally with the bus bar frame 300, but this is not essential. The first convex portion 311 and the second convex portion 321 may be fabricated as separate members from the bus bar frame 300 and attached to the bus bar frame 300 by a predetermined means such as adhesion, welding, or fitting. This allows the energy storage device 10 to be provided with first convex portions 311 and second convex portions 321 having more complex shapes.

[0069] One or both of the first convex portion 311 and the second convex portion 321 may not be provided on the bus bar frame 300. A spacer 150 (see FIG. 7 ) disposed between the first energy storage element 20A and the second energy storage element 20B may include one or both of the first convex portion 311 and the second convex portion 321.

[0070] The energy storage device 10 does not need to include the second protrusion 321. In the present embodiment, the protrusion 346 that protrudes in the negative X-axis direction from the middle portion 345 of the bus bar 340 is disposed between the two first protrusions 311 that are spaced apart in the Y-axis direction. Therefore, even if the energy storage device 10 does not include the second protrusion 321, changes in the posture of the bus bar 340 are suppressed.

[0071] When the energy storage device 10 includes the second convex portion 321, it is sufficient to include at least one second convex portion 321. By arranging the at least one second convex portion 321 on the opposite side of the bus bar 340 from the first convex portion 311, the at least one second convex portion 321, together with the first convex portion 311, can suppress changes in the posture of the bus bar 340, etc.

[0072] In the embodiment, terminal 22 of energy storage element 20 and bus bar 340 are connected by nut 700 that is coupled to shaft portion 23 of terminal 22, but this is not essential. Terminal 22 and bus bar 340 may also be connected by welding, crimping, or the like.

[0073] Any combination of the components included in the above-described embodiments and their modifications is also included within the scope of the present invention.

[0074] 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.

[0075] DESCRIPTION OF SYMBOLS 10 Energy storage device 20 Energy storage element 20A First energy storage element 20B Second energy storage element 21 Container 21a Long side surface 21b Short side surface 21c Terminal arrangement surface 22 Terminal 22A First terminal 22B Second terminal 23 Shaft portion 300 Bus bar frame 301 Bus bar accommodating portion 310 First wall portion 311 First convex portion 312 Opposing wall portion 313 Connecting wall portion 319 First claw portion 320 Second wall portion 321 Second convex portion 329 Second claw portion 330 Linking portion 335 Side wall portion 340 Bus bar 341 First connecting portion 341a, 342a Through hole 342 Second connecting portion 345 Middle portion 346 Protruding portion

Claims

1. An energy storage device comprising: a first storage element and a second storage element aligned in a first direction; a bus bar connected to the first storage element and the second storage element; and a first wall portion arranged on one side of the bus bar in a second direction perpendicular to the first direction, wherein the first storage element has a first terminal on one side in a third direction perpendicular to the first direction and the second direction, and the second storage element has a second terminal on the one side in the third direction, the bus bar comprises: a first connection portion connected to the first terminal, a second connection portion connected to the second terminal, and an intermediate portion which is a portion between the first connection portion and the second connection portion, the intermediate portion having a protrusion protruding to the one side in the second direction, and the first wall portion has two first convex portions protruding toward the bus bar, and the protrusion is arranged between the two first convex portions in the first direction.

2. The energy storage device according to claim 1, further comprising a second wall portion arranged on the other side of the bus bar in the second direction, the second wall portion comprising a second protrusion protruding towards the bus bar.

3. The energy storage device according to claim 2, wherein the second wall portion has two of the second convex portions, and when viewed from the second direction, at least a portion of each of the two second convex portions overlaps with at least one of the two first convex portions.

4. The energy storage device according to claim 2 or 3, further comprising a connecting portion connecting said first convex portion and said second convex portion, said connecting portion being arranged on the other side of said intermediate portion in said third direction.

5. The energy storage device according to any one of claims 1 to 3, wherein each of the two first protrusions comprises an opposing wall portion that faces the bus bar, and a connecting wall portion that connects the opposing wall portion and the first wall portion.

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