Power storage device

Abstract

This power storage device comprises a plurality of power storage elements, a plurality of bus bars which are arranged in a first direction of the plurality of power storage elements and which are connected to the plurality of power storage elements, a bus bar case in which the plurality of bus bars are arranged, and a spacer which is arranged along one or more power storage elements among the plurality of power storage elements, wherein: the bus bar case includes two accommodating portions that are arranged spaced apart in a second direction intersecting the first direction, each of the two accommodating portions accommodating one or more bus bars among the plurality of bus bars, and a connecting portion that extends in the second direction and that connects the two accommodating portions; and the spacer includes a projection that protrudes in the first direction and that is hooked onto the connecting portion in the first direction.

Description

Power storage device

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

[0002] Patent Document 1 discloses an energy storage module including a plurality of energy storage cells, a plurality of resin frames, and a busbar module. The energy storage cells have a pair of external terminals. The busbar module includes a plurality of busbars and a busbar case. The resin frame has a locking portion that locks the busbar case. The busbar case has a locked portion that can be engaged with the locking portion, and a biasing portion that biases the busbar toward the locked portion when the locked portion is engaged with the locking portion.

[0003] JP 2023-112482 A

[0004] In the busbar module of the conventional energy storage module, a resin frame is disposed between a pair of adjacent energy storage cells, and a locking portion of the resin frame locks a locked portion of the busbar case. In this configuration, the locked portion is a dedicated portion for locking with the locking portion. Therefore, providing a locked portion on each busbar case may complicate the configuration of the busbar case.

[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 reliability.

[0006] According to one aspect of the present invention, there is provided an energy storage device comprising: a plurality of energy storage elements; a plurality of bus bars arranged in a first direction of the plurality of energy storage elements and connected to the plurality of energy storage elements; a bus bar case in which the plurality of bus bars are arranged; and a spacer arranged along one or more of the plurality of energy storage elements, wherein the bus bar case comprises two accommodating portions arranged separately in a second direction intersecting the first direction, each accommodating one or more of the plurality of bus bars; and a connecting portion extending in the second direction and connecting the two accommodating portions, and the spacer comprises a protrusion that protrudes in the first direction and is hooked onto the connecting portion in the first direction.

[0007] According to the present invention, it is possible to provide a power storage device with a simple configuration and improved reliability.

[0008] FIG. 1 is a perspective view showing the configuration of an energy storage device according to an embodiment. FIG. 2 is a perspective view showing the configuration of an energy storage unit and a busbar unit according to an embodiment. FIG. 3 is an exploded perspective view of a busbar unit according to an embodiment. FIG. 4 is a perspective view of a busbar, a spacer, and two energy storage elements according to an embodiment. FIG. 5 is an enlarged perspective view showing a protrusion and its surrounding configuration according to an embodiment. FIG. 6 is a perspective view showing the configuration of a connecting portion according to an embodiment. FIG. 7 is a plan view showing the configuration of a busbar case according to an embodiment.

[0009] (1) An energy storage device according to one aspect of the present invention includes a plurality of energy storage elements, a plurality of bus bars arranged in a first direction of the plurality of energy storage elements and connected to the plurality of energy storage elements, a bus bar case in which the plurality of bus bars are arranged, and a spacer arranged along one or more of the plurality of energy storage elements, wherein the bus bar case includes two accommodating sections arranged separately in a second direction intersecting the first direction, each accommodating one or more of the plurality of bus bars, and a connecting section extending in the second direction and connecting the two accommodating sections, and the spacer includes a protrusion that protrudes in the first direction and is hooked onto the connecting section in the first direction.

[0010] In the energy storage device according to one aspect of the present invention, the protrusion of the holder is hooked onto a connecting portion of the bus bar case that connects two housing portions. This restricts movement of the bus bar case. In other words, the connecting portion that connects the housing portions is used as a portion whose movement is restricted by the protrusion, allowing the bus bar case to be positioned with precision. As a result, the positional precision of the multiple bus bars is improved. In this way, the energy storage device according to this aspect is an energy storage device with a simple configuration and improved reliability.

[0011] (2) In the energy storage device described in (1) above, the connecting portion may include a curved portion and a connection portion aligned in the second direction, and the curved portion may have a curved shape that protrudes further than the connection portion in a direction intersecting the second direction.

[0012] According to the energy storage device described in (2) above, even if at least one of the two housing sections is misaligned from its normal (i.e., designed) position due to, for example, size tolerances of the energy storage elements, the curved portion of the connecting portion can efficiently absorb the misalignment of the housing section, thereby enabling the bus bar case to be positioned with respect to the energy storage elements with greater accuracy.

[0013] (3) In the energy storage device described in (2) above, the curved portion may be connected to each of both ends of the connection portion in the second direction.

[0014] According to the energy storage device described in (3) above, in the coupling part, curved parts that easily expand and contract in the second direction are arranged at both ends of the connection part that extends in the second direction, so that the coupling part can more efficiently absorb misalignment of the storage part.

[0015] (4) In the energy storage device described in (2) or (3) above, the cross-sectional area of ​​the connection portion intersecting with the second direction may be smaller than the cross-sectional area of ​​the curved portion intersecting with the direction in which the curved portion extends.

[0016] According to the energy storage device described in (4) above, the cross-sectional area of ​​the connecting portion disposed between the two curved portions in the coupling portion is relatively small, which improves the flexibility of the connecting portion in the second direction, thereby enabling the coupling portion to more efficiently absorb misalignment of the storage portion.

[0017] (5) In the energy storage device described in any one of (1) to (4) above, the connecting portion may be arranged at an end of the busbar case in a third direction that intersects with the first direction and the second direction.

[0018] According to the energy storage device described in (5) above, since the connecting portion is disposed at the end of the bus bar case in the third direction, it is possible to easily check from the outside whether the protrusion is properly hooked onto the connecting portion, which contributes to improving the reliability of the energy storage device.

[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 modifications thereof). 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 examples and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated. In each drawing, the same or similar components are designated by the same reference numerals.

[0020] In the following description and drawings, the X-axis direction is defined as the direction in which a pair of terminals of an energy storage element are aligned, or the direction in which a pair of short side surfaces of a container for the energy storage element face each other. The Y-axis direction is defined as the direction in which a pair of long side surfaces of a container for the energy storage element face each other, the thickness direction (flattening direction) of the container for the energy storage element, or the direction in which multiple energy storage elements of an energy storage unit are aligned. The Z-axis direction is defined as the direction in which the terminals of the energy storage element protrude, the direction in which the container body and the cover plate of the energy storage element are aligned, the direction in which the energy storage unit and the busbar unit are aligned, or the up-down 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; however, 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. Simply referring to the X-axis direction refers to both or either of the positive X-axis direction and the negative X-axis direction. References to one side and the other side of the X-axis direction refer to one and the other of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis and Z-axis directions. Expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the directions or attitudes are not strictly the same. For example, two directions being parallel not only means that the two directions are completely parallel, but also means that the directions are substantially parallel, i.e., there is a difference of, for example, a few percent. In the following description, the term "insulation" means "electrical insulation." The volume resistivity of an insulating material is 1×10 ６ Ωm or more is preferable, and 1×10 ７ Ωm or more is more preferable, and 1×10 １０ More preferably, it is Ωm or more.

[0022] (Embodiment) [1. General Description of Energy Storage Device 1] Fig. 1 is a perspective view showing the configuration of an energy storage device 1 according to an embodiment. Fig. 1 shows a state in which an energy storage unit 10 and a busbar unit 400 are removed from a case main body 610. Fig. 2 is a perspective view showing the configurations of the energy storage unit 10 and the busbar unit 400 according to the embodiment. Fig. 2 shows a state in which the busbar unit 400 is separated from the energy storage unit 10. Fig. 3 is an exploded perspective view of the busbar unit 400 according to the embodiment. Fig. 4 is a perspective view of a busbar 300, a spacer 200, and two energy storage elements 100 according to the embodiment. In Fig. 4, a busbar case 401 is not shown. The two energy storage elements 100 shown in Fig. 4 are adjacent to each other in the Y-axis direction with the spacer 200 sandwiched therebetween.

[0023] The power storage device 1 is a device that can charge electricity from an external source and discharge electricity to an external source. The power storage device 1 is, for example, a battery module (battery assembly) used for power storage or power supply purposes. Specifically, the power storage device 1 is used as a battery for driving or starting the engine of a moving object such as an automobile, a motorcycle, a personal watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, an automatic guided vehicle (AGV), or a railway vehicle for an electric railway. 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 railway vehicle for an electric railway include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0024] 1 , the energy storage device 1 includes an energy storage unit 10, a bus bar unit 400, and a case 600 that houses the energy storage unit 10. In addition to the above components, the energy storage device 1 may also include electrical devices such as a circuit board and a relay that monitor or control the charge state, discharge state, etc. of the energy storage unit 10.

[0025] In this embodiment, the energy storage unit 10 is a battery module having one or more energy storage elements 100. Specifically, the energy storage unit 10 includes a plurality of energy storage elements 100 (34 in this embodiment), a spacer 200 disposed between two adjacent energy storage elements 100 in the Y-axis direction, and spacers 250 disposed on the outer sides of each of the energy storage elements 100 at both ends in the Y-axis direction. The spacer 200 is also referred to as, for example, an "inter-cell spacer." The spacer 250 is also referred to as, for example, an "end spacer." In this embodiment, the spacers 200 and 250 also function as cell holders that hold one or more energy storage elements 100 disposed along the spacer 200 or 250. Specifically, the spacer 200 includes a spacer main body 201 that faces the energy storage element 100 in the Y-axis direction, a spacer bottom wall 203 that faces the bottom surface 113 of the energy storage element 100, and a pair of spacer side wall portions 202 that face the pair of short side surfaces 112 of the energy storage element 100. By including the spacer bottom wall portion 203 and the pair of spacer side wall portions 202, the spacer 200 also functions as a cell holder that holds the energy storage element 100.

[0026] The spacer 200 according to this embodiment further includes protrusions 230 that are hooked onto the connecting portions 430 of the bus bar case 401. The protrusions 230 are provided so as to protrude from the spacer main body 201 in the positive direction of the Z axis. The protrusions 230 of each of the plurality of spacers 200 are hooked onto the connecting portions 430 that are arranged at positions corresponding to the protrusions 230, thereby attaching the bus bar case 401 to the energy storage unit 10. In this state, movement of the bus bar case 401 as a whole relative to the energy storage unit 10 in directions parallel to the XY plane and in the Z axis direction is restricted. Details of the protrusions 230 and the connecting portions 430 will be described later using FIGS. 4 to 7.

[0027] The energy storage unit 10 has a substantially rectangular parallelepiped shape that is long in the Y-axis direction, with a plurality of energy storage elements 100, a plurality of spacers 200, and a pair of spacers 250 arranged in the Y-axis direction. The Y-axis direction is an example of a second direction. The plurality of energy storage elements 100 included in the energy storage unit 10 are electrically connected by a plurality of bus bars 300. The rectangular parallelepiped referred to here is a hexahedron with all faces formed into rectangles or squares.

[0028] In this embodiment, the energy storage unit 10 is a non-constraint type module that does not include restraining members (end plates, side plates, etc.) that restrain the plurality of energy storage elements 100 in the Y-axis direction. However, the energy storage unit 10 may include restraining members that restrain the plurality of energy storage elements 100 and the plurality of spacers 200 and 250 in the Y-axis direction.

[0029] The energy storage element 100 is a secondary battery (single cell), more specifically, a nonaqueous electrolyte secondary battery such as a lithium-ion secondary battery. As shown in FIG. 4 , the energy storage element 100 includes a flat rectangular (square) container 110. The container 110 contains an electrode assembly, a current collector, an electrolyte, and other components (not shown). The electrode assembly may be a wound electrode assembly formed by winding electrode plates and a separator. The electrode assembly may be a stacked electrode assembly formed by stacking multiple flat electrode plates, or an electrode assembly having a bellows-like structure formed by repeatedly folding long strip-shaped electrode plates. The type of electrolyte contained in the container 110 is not particularly limited as long as it does not impair the performance of the energy storage element 100, and various types can be selected. The energy storage element 100 may be a secondary battery other than a nonaqueous electrolyte secondary battery, or a capacitor. The energy storage element 100 may also be a primary battery. The energy storage element 100 may be a battery using a solid electrolyte. The energy storage element 100 may be a pouch-type energy storage element. The shape of the energy storage element 100 is not limited to the above-mentioned rectangular shape, and may be other shapes such as a polygonal column shape, a cylindrical shape, an elliptical column shape, or an oblong column shape.

[0030] 4, the container 110 is a rectangular parallelepiped case having a pair of long sides 111, a pair of short sides 112, and a bottom surface 113 formed by the container body, and a terminal placement surface 130 formed by a cover plate. After the electrode assembly and the like are housed inside the container body, the container body and the cover plate are welded together to seal the interior of the container 110. The material of the container 110 is not particularly limited, but is preferably a weldable metal such as stainless steel, aluminum, an aluminum alloy, iron, or plated steel sheet.

[0031] The energy storage element 100 includes a terminal 140 arranged in the positive direction of the Z axis. The positive direction of the Z axis is an example of a first direction. The terminal 140 is electrically connected to an electrode assembly housed in the container 110. More specifically, a pair of terminals 140 are arranged to protrude in the positive direction of the Z axis from a terminal arrangement surface 130 of the container 110. A gas exhaust valve 131 is further provided on the terminal arrangement surface 130. One of the pair of terminals 140 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. The terminal 140 is formed of a metal such as aluminum, an aluminum alloy, copper, or a copper alloy.

[0032] As shown in FIG. 4 , the bus bar 300 according to this embodiment includes a first terminal connection portion 310, a second terminal connection portion 320, and an intermediate connection portion 350. The first terminal connection portion 310 and the second terminal connection portion 320 are each a plate-shaped portion joined to the upper surface of the terminal 140. More specifically, the first terminal connection portion 310 includes a first joining plate portion 311 and a second joining plate portion 312, each joined to the terminal 140. There are no particular limitations on the method for joining the first terminal connection portion 310 and the second terminal connection portion 320 to the terminal 140, but laser welding, for example, may be used. The intermediate connection portion 350 is a plate-shaped portion that electrically and mechanically connects the first terminal connection portion 310 and the second terminal connection portion 320. In this embodiment, the intermediate connection portion 350 is integral with the first terminal connection portion 310 and the second terminal connection portion 320. The shape of the bus bar 300 included in the energy storage device 1 is not limited to the shape shown in FIG. 4 , etc. The bus bar 300 may have any shape and size as long as it can electrically connect at least two energy storage elements 100 adjacent in the Y-axis direction. The bus bar 300 may be realized by a flat metal plate parallel to the XY plane.

[0033] The energy storage device 1 includes a plurality of bus bars 300, which are connected to a plurality of energy storage elements 100. Specifically, each of the plurality of bus bars 300 electrically and mechanically connects two energy storage elements 100 adjacent to each other in the Y-axis direction.

[0034] The case 600 is a container having a substantially rectangular parallelepiped (box-like) shape that houses the energy storage unit 10. The case 600 is disposed outside the energy storage unit 10 and protects the energy storage unit 10 from impacts and the like. The case 600 is formed from a metal member such as aluminum, an aluminum alloy, stainless steel, iron, or a plated steel plate. In this embodiment, the case 600 is formed by die-casting aluminum (aluminum die-casting). Instead of the case 600, a case formed from an insulating member such as a resin material may be used as the case that houses the energy storage unit 10.

[0035] As shown in FIG. 1 , the case 600 has a case main body 610. The case main body 610 is a housing (enclosure) having an opening 610a formed in the positive direction of the Z axis and sized to allow insertion of the power storage unit 10. The case main body 610 includes a case side wall 611 facing the power storage unit 10 in the X axis direction, a case side wall 612 facing the power storage unit 10 in the Y axis direction, and a case bottom wall 615 supporting the power storage unit 10 from the negative direction of the Z axis. The X axis direction is an example of a third direction. The case 600 may further include a lid (not shown) that closes the opening 610a of the case main body 610.

[0036] The busbar unit 400 includes a plurality of busbars 300 and a busbar case 401 that holds the plurality of busbars 300. The busbar unit 400 is arranged in the positive direction of the Z axis of the energy storage unit 10. The busbar case 401 is a member formed of an insulating material such as resin, and includes a plurality of housing portions 405 that house the plurality of busbars 300. The housing portions 405 are box-shaped portions that house and hold the busbars 300 with their undersides (the surfaces facing the negative Z axis) exposed. In this embodiment, as shown in FIGS. 1 and 2 , two adjacent energy storage elements 100 in the Y axis direction are connected in series by the busbars 300. That is, the plurality of energy storage elements 100 included in the energy storage unit 10 are connected in series by the plurality of busbars 300. Each of the plurality of busbars 300 is held in a housing portion 405 located at a position corresponding to the busbar 300. Two adjacent storage sections 405 in the Y-axis direction are separated in the Y-axis direction and connected by a connecting section such as a connecting section 430. The connection structure of the multiple storage sections 405 will be described later with reference to FIGS.

[0037] In the present embodiment, a bus bar 382 is joined to the negative terminal 140 of the energy storage element 100 at the end of the energy storage unit 10 facing the positive direction of the Y axis, and a bus bar 381 is joined to the positive terminal 140 of the energy storage element 100 at the end of the energy storage unit 10 facing the negative direction of the Y axis. These bus bars 382 and 381 are also held in a bus bar case 401. As shown in FIG. 3 , the bus bar 382 may be provided with a negative general terminal 392 that protrudes in the positive direction of the Z axis. The bus bar 381 may be provided with a positive general terminal 391 that protrudes in the positive direction of the Z axis. The negative general terminal 392 and the positive general terminal 391 are connected to another device via a cable or the like, so that the energy storage device 1 supplies power to the other device. The energy storage device 1 may be charged by power supplied from the other device instead of or in addition to supplying power to the other device. The negative electrode general terminal 392 and the positive electrode general terminal 391 may each protrude from the inside to the outside of the case 600 and be used as an external terminal.

[0038] The busbar unit 400 may include other members such as a wiring board disposed in the busbar case 401. The wiring board may include wiring electrically connected to each of the plurality of busbars 300. In this case, a control device that controls the charging and discharging of the energy storage device 1 may be electrically connected to the wiring board, so that the control device may detect the voltage of each of the plurality of energy storage elements 100 via the wiring board and control the charging and discharging of the plurality of energy storage elements 100 based on the detection results.

[0039] 2. Regarding the protrusion 230 and the connecting portion 430 Next, the protrusion 230 and the connecting portion 430 according to this embodiment will be described using Figures 5 to 7 in addition to Figures 1 to 4 described above. Below, focusing on one spacer 200 out of the plurality of spacers 200, the protrusion 230 provided on the spacer 200, the connecting portion 430 to which the protrusion 230 is hooked, and the surrounding configuration will be described.

[0040] FIG. 5 is an enlarged perspective view showing the configuration of the protrusion 230 and its surroundings according to the embodiment. In FIG. 5, the energy storage elements 100 other than the two energy storage elements 100 shown in FIG. 5 are omitted. FIG. 6 is a perspective view showing the configuration of the coupling portion 430 according to the embodiment. In FIG. 6, the bus bar 300 accommodated in the accommodation portion 405 is omitted. FIG. 7 is a plan view (viewed from the positive direction of the Z axis) showing the configuration of the bus bar case 401 according to the embodiment. In FIG. 7, a portion of the bus bar case 401 is enlarged and a pattern is applied to the background of the bus bar case 401 in order to clearly show the coupling structure of two adjacent accommodation portions 405.

[0041] In the following, when describing two adjacent storage sections 405 in the Y-axis direction, the storage section 405 in the negative Y-axis direction will be referred to as storage section 405A, and the storage section 405 in the positive Y-axis direction will be referred to as storage section 405B.

[0042] As shown in FIGS. 5 to 7 , the bus bar case 401 includes two housing portions 405 that are spaced apart in the Y-axis direction, and a connecting portion 430 that connects the two housing portions 405. The connecting portion 430 is a portion that extends in the Y-axis direction between the two housing portions 405 in the Y-axis direction, and is located at the end of the bus bar case 401 in the X-axis direction. The connecting portion 430 is located outward of the two housing portions 405 in the X-axis direction. More specifically, the connecting portion 430 includes two base portions 432 that connect the two housing portions 405, and a connecting portion 435 that is located between the two base portions 432. Each of the two base portions 432 extends from the two housing portions 405 in the positive direction of the X-axis, so that the connecting portion 435 is spaced apart from the two housing portions 405 in the positive direction of the X-axis. As a result, as shown in FIG. 7 , a space is formed between the connecting portion 430 and the two housing portions 405. The connecting portion 430 having this configuration can expand and contract in the Y-axis direction by elastically deforming in the Y-axis direction. In other words, the distance G (see FIG. 6) between the accommodating portion 405A and the accommodating portion 405B shown in FIGS. 5 to 7 is variable. Therefore, misalignment between the accommodating portion 405A and the accommodating portion 405B is absorbed by the connecting portion 430. Specifically, the side wall portion 406A of the accommodating portion 405A facing the positive Y-axis direction and the side wall portion 406B of the accommodating portion 405B facing the negative Y-axis direction are spaced apart in the Y-axis direction over the entire area in the Z-axis direction (see FIGS. 6 and 7). That is, a gap penetrating in the Z-axis direction exists between the side wall portions 406A and 406B, and the length of this gap in the Y-axis direction is the distance G. In other words, the bus bar case 401 has an opening penetrating in the Z-axis direction between the accommodating portion 405A and the accommodating portion 405B, and the length of this opening in the Y-axis direction is the distance G.

[0043] More specifically, the accommodating portion 405A and the accommodating portion 405B are further connected by an inner connecting portion 460 disposed in the negative X-axis direction of the accommodating portion 405A and the accommodating portion 405B. Like the connecting portion 430, the inner connecting portion 460 is also elastically deformable in the Y-axis direction, thereby enabling expansion and contraction in the Y-axis direction. Thus, the accommodating portion 405A and the accommodating portion 405B are connected at their ends in the X-axis direction by connecting portions (the connecting portion 430 and the inner connecting portion 460) that are expandable and contractible in the Y-axis direction in response to displacement of at least one of the two accommodating portions 405A and 405B in the Y-axis direction (in other words, relative displacement). This allows displacement of one of the accommodating portions 405A and 405B in the Y-axis direction relative to the other, while suppressing a decrease in the mechanical strength of the bus bar case 401.

[0044] The connecting portion 430 that connects the two housing portions 405 as described above also functions as a portion that mechanically engages with the energy storage unit 10. Specifically, as shown in FIGS. 4 and 5 , the spacer 200 included in the energy storage unit 10 includes a protrusion 230 that protrudes in the positive direction of the Z axis. The protrusion 230 is disposed at the end of the spacer main body 201 in the X axis direction on the positive side of the Z axis direction. When the energy storage element 100 and the spacer 200 are combined, the protrusion 230 is positioned further outward in the X axis direction than the terminals 140 of the energy storage element 100. In other words, the protrusion 230 located at the end of the spacer 200 in the positive direction of the X axis is positioned further in the positive X axis direction than the terminal 140 of the pair of terminals 140 of the energy storage element 100 that is positioned in the positive X axis direction. The protrusion 230 located at the end of the spacer 200 in the negative X axis direction is positioned further in the negative X axis direction than the terminal 140 of the pair of terminals 140 of the energy storage element 100 that is positioned in the negative X axis direction. 5, the protrusion 230 is hooked onto the connecting portion 430. More specifically, the protrusion 230 has a claw portion 231 that protrudes in the positive direction of the X-axis. The claw portion 231 is positioned above the connection portion 435 of the connecting portion 430 (in the positive direction of the Z-axis), thereby allowing the protrusion 230 to be hooked onto the connecting portion 430.

[0045] The energy storage device 1 according to this embodiment includes one or more pairs of connecting portions 430 and protrusions 230 that are hooked onto the connecting portions 430. As a result, the bus bar case 401, which includes one or more connecting portions 430, is restricted in its overall movement relative to the energy storage unit 10, that is, movement parallel to the XY plane and movement in the Z-axis direction. In other words, the position of the bus bar case 401 relative to the energy storage unit 10 is determined. As a result, the bus bar case 401 can be positioned with precision, and as a result, the positional precision of the multiple bus bars 300 is improved.

[0046] 1 to 3 and 5 to 7 show a plurality of coupling portions 430 arranged at the end of the bus bar case 401 in the positive direction of the X axis. However, in the present embodiment, a plurality of coupling portions 430 are also arranged at the end of the bus bar case 401 in the negative direction of the X axis, and protrusions 230 arranged at positions corresponding to the coupling portions 430 are hooked onto each of the plurality of coupling portions 430. In other words, the bus bar case 401 and a plurality of spacers 200 are fixed at a plurality of positions on two outer edges of the bus bar case 401 along the Y axis direction, both on the outer edge in the positive direction of the X axis and on the outer edge in the negative direction of the X axis. This allows the bus bar case 401, which is elongated in the Y axis direction, to be attached to the energy storage unit 10 in a well-balanced manner.

[0047] In this embodiment, as shown in FIG. 7 , storage section 405A and storage section 405A on the negative Y-axis side are separated in the Y-axis direction and are connected by outer connecting section 450 and inner connecting section 460. Outer connecting section 450 is a U-shaped section in a plan view. Outer connecting section 450 does not have the function of hooking protrusion 230, but like connecting section 430, outer connecting section 450 is elastically deformed in the Y-axis direction and is therefore capable of expanding and contracting in the Y-axis direction. Furthermore, storage section 405B and storage section 405B on the positive Y-axis side are separated in the Y-axis direction and are connected by outer connecting section 450 and inner connecting section 460.

[0048] As described above, among the multiple accommodation sections 405 arranged in the Y-axis direction, two adjacent accommodation sections 405 are connected by connecting sections (connecting section 430, inner connecting section 460, and outer connecting section 450) that are expandable and contractible in the Y-axis direction. Therefore, in the bus bar case 401 whose movement as a whole is restricted, each of the multiple accommodation sections 405 has a degree of freedom in its position in the Y-axis direction. Therefore, the bus bar case 401 can appropriately hold the multiple bus bars 300 while accommodating the size tolerances of the energy storage elements 100 or the bus bars 300. Furthermore, when the bus bar 300 connected to the energy storage elements 100 deforms or displaces in the Y-axis direction due to expansion of the energy storage elements 100 or the like, the accommodation section 405 that accommodates the bus bar 300 can displace in the Y-axis direction in response to the deformation or displacement of the bus bar 300. In other words, the accommodation section 405 is prevented from excessively restricting the deformation or displacement of the bus bar 300. As a result, problems such as defects at the joints between the busbars 300 and the energy storage elements 100 caused by excessively restricting the deformation or displacement of the busbars 300 are unlikely to occur.

[0049] The technical features of the energy storage device 1 configured as above are described below, for example.

[0050] The energy storage device 1 according to this embodiment includes a plurality of energy storage elements 100, a plurality of bus bars 300, a bus bar case 401 in which the plurality of bus bars 300 are arranged, and a spacer 200. The plurality of bus bars 300 are arranged in the positive direction of the Z axis of the plurality of energy storage elements 100 and are connected to the plurality of energy storage elements 100. The spacer 200 is arranged along one or more of the plurality of energy storage elements 100. The bus bar case 401 includes two accommodating portions 405 that are arranged separately in the Y axis direction, and a connecting portion 430 that extends in the Y axis direction and connects the two accommodating portions 405. Each of the two accommodating portions 405 accommodates one or more of the plurality of bus bars 300. The spacer 200 includes a protrusion 230 that protrudes in the positive direction of the Z axis and is hooked onto the connecting portion 430 in the positive direction of the Z axis.

[0051] As described above, in the energy storage device 1 according to this embodiment, the protrusions 230 of the holder are hooked onto the connecting portions 430 that connect the two housing portions 405 that are disposed separately in the Y-axis direction in the bus bar case 401. This restricts movement of the bus bar case 401. In other words, the connecting portions 430 that connect the housing portions 405 are used as the portions whose movement is restricted by the protrusions 230, thereby enabling the bus bar case 401 to be positioned with precision. As a result, the positional precision of the multiple bus bars 300 is improved. In other words, in the energy storage device 1 according to this embodiment, it is not necessary to provide the bus bar case 401 with a dedicated portion for restricting movement of the bus bar case 401. As described above, the energy storage device 1 according to this aspect is an energy storage device 1 that has a simple configuration and improved reliability.

[0052] In the present embodiment, the connecting portion 430 that connects the two accommodation portions 405 that are disposed separately in the Y-axis direction extends in the Y-axis direction. Therefore, even if one of the protrusion 230 and the connecting portion 430 is slightly misaligned in the Y-axis direction relative to the other, the protrusion 230 can be hooked onto the connecting portion 430. Therefore, the bus bar case 401 can be accurately positioned in the energy storage unit 10 while accommodating the size tolerances of the bus bar case 401, the spacer 200, etc.

[0053] The linking portion 430 is connected to each of the two storage portions 405 at their ends in the X-axis direction, which are separated in the Y-axis direction. The connection portion 435 of the linking portion 430 is disposed at a position facing the gap in the Y-axis direction between the two storage portions 405 in the X-axis direction. The spacer 200 having the protrusion 230 fixed to this connection portion 435 is positioned between the two energy storage elements 100 in the Y-axis direction.

[0054] In other words, when the two energy storage elements 100 are used as a reference, the connecting portion 430 is provided between the Y-axis direction of the two housing portions 405 of the two bus bars 300 associated with each of the energy storage elements 100, and the protrusion 230 is provided on the spacer 200 disposed between the two energy storage elements 100. This allows the bus bar case 401 and the spacer 200, which are different members, to be fixed at appropriate positions within a limited space without adding an extra shape to the energy storage device 1.

[0055] The connecting portion 430 is disposed at the end of the bus bar case 401 in the negative Z-axis direction (the end closest to the spacer 200) (see FIGS. 2, 3, and 5). This allows the length of the protrusion 230 provided at the end of the spacer 200 in the positive Z-axis direction to be relatively short. As a result, the protrusion 230 is less likely to deform. More specifically, since the protrusion 230 is less likely to deform, the claw portion 231 provided at the end of the protrusion 230 in the positive Z-axis direction and hooked onto the connecting portion 430 is suppressed from being displaced. This contributes to improving the positional accuracy and / or positional stability of the bus bar case 401.

[0056] More specifically, the linking portion 430 according to this embodiment includes a connecting portion 435 extending in the Y-axis direction, as well as a curved portion 431. That is, the linking portion 430 according to this embodiment includes the curved portion 431 and the connecting portion 435 aligned in the Y-axis direction. The curved portion 431 has a curved shape that protrudes further than the connecting portion 435 in a direction intersecting the Y-axis direction (the X-axis direction in this embodiment) (see FIGS. 5 to 7).

[0057] The curved portion 431 of the connecting portion 435 is more likely to expand and contract in the Y-axis direction than the linear connecting portion 435. Therefore, in the event that at least one of the two housing portions 405 is displaced from its normal (i.e., designed) position due to size tolerances of the multiple energy storage elements 100, the curved portion 431 of the connecting portion 430 can efficiently absorb the displacement of the housing portion 405. This allows the bus bar case 401 to be positioned with respect to the energy storage elements 100 with greater precision. The curved portion 431 efficiently absorbs the displacement of the housing portion 405, thereby preventing excessive restriction of deformation or displacement of the bus bar 300 housed in the housing portion 405, for example, when the energy storage elements 100 expand. This prevents defects from occurring at the joint between the bus bar 300 and the energy storage elements 100.

[0058] The curved portion 431 of the connecting portion 430 may include a base portion 432 (see FIGS. 5 to 7) that is connected to the storage portion 405. In the connecting portion 430, the range that includes the curved portion that protrudes beyond the connecting portion 435 and the portion that is connected to the storage portion 405 may be the "curved portion 431."

[0059] More specifically, in the coupling portion 430 according to this embodiment, the curved portions 431 are connected to both ends of the connection portion 435 in the Y-axis direction.

[0060] That is, in the coupling portion 430, the curved portions 431 that easily expand and contract in the Y-axis direction are arranged at both ends of the connection portion 435 that extends in the Y-axis direction. Therefore, misalignment of the accommodation portion 405 can be absorbed more efficiently.

[0061] In this embodiment, the area S1 of the cross section of the connecting portion 435 intersecting with the Y-axis direction is smaller than the area S2 of the cross section of the curved portion 431 intersecting with the extension direction of the curved portion 431. Specifically, as shown in Fig. 6, when the area S1 of the cross section of the connecting portion 435 perpendicular to the Y-axis direction and the area S2 of the cross section of the curved portion 431 perpendicular to the extension direction of the curved portion 431 are taken as S1 and S2, respectively, S1 < S2.

[0062] In this way, the cross-sectional area of ​​the connecting portion 435 disposed between the two curved portions 431 in the linking portion 430 is relatively small, which improves the stretchability of the connecting portion 435 in the Y-axis direction. This improves the stretchability of the linking portion 430 as a whole, and as a result, the positional deviation of the accommodation portion 405 can be absorbed more efficiently.

[0063] In this embodiment, the thicknesses of the connecting portion 435 and the curved portion 431 are substantially the same (see FIG. 7 ), and their upper and lower widths (lengths in the Z-axis direction) are different, resulting in the difference in cross-sectional area. Specifically, as shown in FIG. 6 , if the length of the connecting portion 435 in the Z-axis direction is W1 and the length of the curved portion 431 in the Z-axis direction is W2, then W1 < W2. Furthermore, in the Z-axis direction, the end of the connecting portion 435 in the negative Z-axis direction and the end of the curved portion 431 in the negative Z-axis direction are located at the same position. That is, the linking portion 430 has a recess 436 recessed in the negative Z-axis direction at the position of the connecting portion 435. In this embodiment, the claw portion 231 of the protrusion 230 (see FIG. 5 ) is inserted into the recess 436 of the linking portion 430. In this configuration, the length of the claw portion 231 in the Y-axis direction is shorter than the length of the recess 436 in the Y-axis direction. That is, the recess 436 is provided in the connecting portion 430 so as to allow some positional misalignment of the protrusion 230 and the connecting portion 430 relative to the other, while restricting the movement of the connecting portion 430 in the Y-axis direction by the protrusion 230.

[0064] In this embodiment, the connecting portions 430 are arranged at the ends in the X-axis direction of the bus bar case 401. More specifically, a plurality of connecting portions 430 are arranged at each of the ends in the positive direction of the X-axis and the negative direction of the X-axis of the bus bar case 401.

[0065] In this way, because the connecting portions 430 are disposed at the ends of the bus bar case 401 in the X-axis direction, it is easy to check from the outside whether the protrusions 230 are properly hooked onto the connecting portions 430. Furthermore, it is easy to align the bus bar case 401 with the energy storage unit 10 in order to hook the protrusions 230 onto the connecting portions 430. These facts contribute to improving the reliability of the energy storage device 1.

[0066] [3. Description of Modifications] While the energy storage device 1 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] In the above embodiment, as shown in FIG. 1 , a spacer 200 is always disposed between two adjacent energy storage elements 100 in the energy storage unit 10. However, this is not essential. When two or more of the energy storage elements 100 included in the energy storage unit 10 are connected in parallel, the spacer 200 does not have to be disposed between two adjacent energy storage elements 100 among the two or more energy storage elements 100. When two or more energy storage elements 100 connected in parallel are grouped into energy storage element 100 groups, the spacer 200 may be disposed only between two adjacent groups of energy storage elements 100. Even in this case, the spacer 200 includes the protrusion 230, which can be hooked onto the connecting portion 430 of the bus bar case 401. In other words, the connecting portion 430 can be used to accurately position the bus bar case 401.

[0068] It is not necessary for all of the plurality of spacers 200 included in the energy storage unit 10 to have the protrusions 230. When the connecting portion 430 is not arranged in the positive direction of the Z axis of the spacer 200, each of the plurality of spacers 200 does not have to have the protrusions 230. However, from the viewpoint of efficiently manufacturing the plurality of spacers 200 by standardizing the plurality of spacers 200, for example, it is preferable that the plurality of spacers 200 have the same configuration, that is, that each of the plurality of spacers 200 has the protrusions 230.

[0069] The bus bar case 401 does not necessarily have to include multiple connecting portions 430. The bus bar case 401 may include at least one connecting portion 430. When the bus bar case 401 includes multiple connecting portions 430, it is not necessary for the protrusions 230 to be hooked onto all of the multiple connecting portions 430. In other words, by hooking the protrusions 230 of one spacer 200 included in the energy storage unit 10 onto one connecting portion 430 included in the bus bar case 401, it is possible to restrict the movement of the bus bar case 401 and / or determine the position thereof.

[0070] In the above embodiment, the curved portion 431 of the linking portion 430 has a curved shape that protrudes in the positive X-axis direction beyond the connecting portion 435, but the protruding direction of the curved portion 431 is not limited to this. The protruding direction of the curved portion 431 may be the negative X-axis direction, the positive Z-axis direction, or the negative Z-axis direction. If the curved portion 431 has a curved shape that protrudes in a direction intersecting the Y-axis direction, the elasticity of the linking portion 430 as a whole in the Y-axis direction is improved.

[0071] It is not essential that the connecting portion 430 include the curved portion 431. The connecting portion 430 may be configured with a connecting portion 435 extending in the Y-axis direction and a base portion 432 extending in the X-axis direction and connected to each of both ends of the connecting portion 435 in the Y-axis direction. Even in this case, the connecting portion 430 can expand and contract in the Y-axis direction by the connecting portion 435 expanding and contracting in the Y-axis direction and / or the base portion 432 tilting in the X-axis direction.

[0072] When the connecting portion 430 includes the curved portions 431, the number of curved portions 431 does not need to be two. Only one curved portion 431 may be provided at one of the two ends in the Y-axis direction of the connecting portion 435 extending in the Y-axis direction, or at the center of the connecting portion 435, for example. A curved portion 431 may be provided at each of the two ends in the Y-axis direction of the connecting portion 435 extending in the Y-axis direction and at the center of the connecting portion 435. In other words, the connecting portion 430 may include three curved portions 431. In either case, the stretchability of the connecting portion 430 is improved compared to when the connecting portion 430 does not include the curved portions 431.

[0073] It is not essential that the cross-sectional area S1 of the connecting portion 435 intersecting with the Y-axis direction be smaller than the cross-sectional area S2 of the curved portion 431 intersecting with the direction in which the curved portion 431 extends. The cross-sectional area of ​​the linking portion 430 intersecting with the direction in which the linking portion 430 extends may be constant in the extension direction. Even in this case, the linking portion 430 is extendable and contractable in the Y-axis direction, and the protrusion 230 can be hooked onto the linking portion 430.

[0074] The coupling portion 430 may be disposed at a position other than the end of the bus bar case 401 in the X-axis direction. When the bus bar case 401 includes, at its end in the Y-axis direction, two accommodation portions 405 aligned in the X-axis direction and connected by the coupling portion 430, the coupling portion 430 may be disposed at the end of the bus bar case 401 in the Y-axis direction. In this case, the spacer 250 (see FIG. 1 ) included in the energy storage unit 10 may include a protrusion 230 that hooks onto the coupling portion 430. An inner coupling portion 460 (see FIGS. 5 and 7 ) that connects the two accommodation portions 405 may function as a coupling portion onto which the protrusion of the spacer 200 hooks. In this case, the spacer 200 may include, at a position corresponding to the inner coupling portion 460, a protrusion of a shape and size that can hook onto the inner coupling portion 460. However, from the viewpoint of being able to easily check from the outside whether the protrusion 230 is properly hooked onto the connecting portion 430, it is preferable that the connecting portion 430 be positioned at the end of the bus bar case 401 in the X-axis direction or the end of the bus bar case 401 in the Y-axis direction.

[0075] The shapes and sizes of the inner connecting portion 460 and the outer connecting portion 450 are not limited to those shown in Figures 5 and 7. The inner connecting portion 460 may have the same shape as the connecting portion 430 according to the above embodiment. In this case, the inner connecting portion 460 may function as a connecting portion onto which the protrusion of the spacer 200 is hooked, as described above.

[0076] The energy storage device 1 does not need to include the case 600. A structure including the energy storage elements 100, the spacers 200, the plurality of bus bars 300, and the bus bar case 401 may be housed as the energy storage device 1 in some kind of device, a rack, or the like.

[0077] Any combination of the components of the above-described embodiment and its modifications is also included within the scope of the present invention.

[0078] 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.

[0079] REFERENCE SIGNS LIST 1 Energy storage device 10 Energy storage unit 100 Energy storage element 200, 250 Spacer 201 Spacer body 230 Protrusion 231 Claw portion 300, 381, 382 Bus bar 400 Bus bar unit 401 Bus bar case 405, 405A, 405B Storage portion 406A, 406B Side wall portion 430 Coupling portion 431 Curved portion 432 Base portion 435 Connection portion 436 Recess 450 Outer coupling portion 460 Inner coupling portion

Claims

1. An energy storage device comprising: a plurality of energy storage elements; a plurality of bus bars arranged in a first direction of the plurality of energy storage elements and connected to the plurality of energy storage elements; a bus bar case in which the plurality of bus bars are arranged; and a spacer arranged along one or more of the plurality of energy storage elements, wherein the bus bar case comprises: two accommodating portions arranged separately in a second direction intersecting the first direction, each accommodating one or more of the plurality of bus bars; and a connecting portion extending in the second direction and connecting the two accommodating portions; and the spacer has a protrusion that protrudes in the first direction and is hooked onto the connecting portion in the first direction.

2. The energy storage device according to claim 1, wherein the coupling portion comprises a curved portion and a connection portion aligned in the second direction, and the curved portion has a curved shape that protrudes further than the connection portion in a direction intersecting the second direction.

3. The energy storage device according to claim 2, wherein the curved portion is connected to each of both ends of the connection portion in the second direction.

4. The energy storage device according to claim 2 or 3, wherein the cross-sectional area of ​​the connection portion intersecting with the second direction is smaller than the cross-sectional area of ​​the curved portion intersecting with the direction in which the curved portion extends.

5. The energy storage device according to any one of claims 1 to 3, wherein the connecting portion is disposed at an end of the bus bar case in a third direction that intersects with the first direction and the second direction.

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