Power storage device

Abstract

This power storage device comprises a first power storage element, a spacer, a busbar, and a busbar holder. The first power storage element and the spacer are arranged side by side in a first direction. The first power storage element includes a first terminal disposed in a second direction that intersects with the first direction. The bus bar is joined to the first terminal. The spacer includes a first opposed portion. The busbar holder has a second opposed portion opposed to the first opposed portion in the first direction. The second opposed portion is disposed between the first opposed portion and a portion of the busbar in the first direction.

Description

Power storage device

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

[0002] Patent Document 1 discloses a power supply device including a battery assembly made up of multiple cells and a busbar module. The busbar module includes a case that is assembled to the battery assembly and busbars that are supported by the case and electrically connected to electrodes of the cells of the battery assembly. The case is integrally molded from, for example, an electrically insulating synthetic resin and has multiple busbar accommodating portions. The busbar accommodating portions are arranged in two rows along the arrangement direction of the multiple cells. The busbar accommodating portions are formed in a frame shape, and the busbars are accommodated within the busbar accommodating portions.

[0003] Japanese Patent Application Laid-Open No. 2021-086794

[0004] In the conventional busbar module described above, each of the multiple busbars is accommodated in a busbar accommodating portion of the case. The busbar accommodating portion is configured to support the busbar and surround the busbar in a plan view. By arranging the busbar module configured in this manner in the battery assembly, multiple busbars can be arranged for multiple unit cells. However, in this case, considering factors such as misalignment of the busbars in the busbar accommodating portion, it may be difficult to accurately align the busbars with the electrode positions of the unit cells. As a result, there is a risk that the busbars and the electrodes of the unit cells may not be joined properly.

[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 improved reliability.

[0006] An energy storage device according to one embodiment of the present invention comprises a first energy storage element, a spacer, a bus bar, and a bus bar holder, wherein the first energy storage element and the spacer are arranged side by side in a first direction, the first energy storage element comprises a first terminal arranged in a second direction intersecting the first direction, the bus bar is joined to the first terminal, the spacer comprises a first opposing portion, and the bus bar holder comprises a second opposing portion opposing the first opposing portion in the first direction, the second opposing portion being arranged between the first opposing portion and a portion of the bus bar in the first direction.

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

[0008] FIG. 1 is a perspective view showing the configuration of an energy storage device according to an embodiment. FIG. 2 is an exploded perspective view of a busbar unit according to an embodiment. FIG. 3 is a perspective view of a busbar, a spacer, and two energy storage elements according to an embodiment. FIG. 4 is an enlarged perspective view showing the configuration of a busbar and its surroundings according to an embodiment. FIG. 5 is a perspective view showing the configuration of a busbar accommodating portion according to an embodiment. FIG. 6 is a plan view showing the positional relationship between a first opposing portion, a second opposing portion, and a busbar according to an embodiment. FIG. 7 is a cross-sectional view showing the positional relationship between a first opposing portion, a second opposing portion, and a busbar according to an embodiment.

[0009] (1) An energy storage device according to one aspect of the present invention comprises a first energy storage element, a spacer, a bus bar, and a bus bar holder, wherein the first energy storage element and the spacer are arranged side by side in a first direction, the first energy storage element comprises a first terminal arranged in a second direction intersecting the first direction, the bus bar is joined to the first terminal, the spacer comprises a first opposing portion, and the bus bar holder comprises a second opposing portion opposing the first opposing portion in the first direction, the second opposing portion being arranged between the first opposing portion and a portion of the bus bar in the first direction.

[0010] According to the energy storage device described in (1) above, in the alignment direction (first direction) of the first energy storage element and the spacer, the first opposing portion of the spacer faces the second opposing portion of the bus bar holder, and the second opposing portion is disposed between the first opposing portion and a portion of the bus bar. Therefore, the first opposing portion of the spacer can limit movement of the bus bar in the first direction via the second opposing portion. Therefore, the first opposing portion of the spacer can guide the bus bar to a position suitable for joining the bus bar and the first terminal. As a result, the bus bar can be joined to the first terminal with high accuracy. Thus, the energy storage device according to this aspect is an energy storage device with improved reliability.

[0011] (2) In the energy storage device described in (1) above, the first opposing portion may be in contact with the second opposing portion in the first direction, and the second opposing portion may be fixed at one end on the busbar holder in a direction intersecting the first direction, and not fixed at the other end on the one direction.

[0012] According to the energy storage device described in (2) above, the second opposing portion is in contact with the first opposing portion in the first direction, thereby efficiently displacing or deforming in a direction toward the corresponding part of the bus bar, thereby efficiently guiding the bus bar to an appropriate position.

[0013] (3) In the energy storage device described in (2) above, the busbar holder may have an intermediate wall portion located between the first opposing portion and the portion of the busbar in the first direction, and the second opposing portion may be a part of the intermediate wall portion.

[0014] According to the electricity storage device described in (3) above, the second opposing portion is provided as a part of the intermediate wall portion, and therefore the mechanical strength of the second opposing portion is improved.

[0015] (4) The energy storage device described in any one of (1) to (3) above may further include a second energy storage element, the second energy storage element including a second terminal arranged in the second direction, the spacer being positioned between the first energy storage element and the second energy storage element in the first direction, and the bus bar being joined to the first terminal and the second terminal.

[0016] According to the energy storage device described in (4) above, the bus bar for connecting two adjacent energy storage elements in the first direction across the spacer is restricted in movement by the first opposing portion of the spacer, thereby positioning the bus bar at a position suitable for joining to the terminals of the two energy storage elements.

[0017] (5) In the energy storage device according to any one of (1) to (4) above, the first opposing portion may be aligned with the first terminal in the first direction.

[0018] According to the energy storage device described in (5) above, the first opposing portions are arranged within the width of the first terminals in a direction (third direction) intersecting the first and second directions, and therefore the second opposing portions can be provided on the busbar holder without increasing the width of the busbar holder in the third direction.

[0019] (6) In the energy storage device described in any one of (1) to (5) above, the second opposing portion may have a convex portion that protrudes toward the portion of the bus bar, and the bus bar may have a concave portion into which at least a portion of the convex portion is inserted.

[0020] According to the energy storage device described in (6) above, at least a portion of the protrusion of the opposing portion is inserted into the recess of the busbar in the first direction. This restricts movement of the busbar in a direction (third direction) intersecting the first and second directions. That is, the first opposing portion can also restrict movement of the busbar in the third direction via the second opposing portion. As a result, the busbar is more reliably guided to an appropriate position.

[0021] 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.

[0022] 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.

[0023] In the following description, the positive X-axis direction refers to the direction of the X-axis arrow, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. 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 orientations, such as parallel and perpendicular, may also include cases where the directions or orientations 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." It is preferable that the insulating material be formed from a material with a volume resistivity of 1×10 Ω-m or more.

[0024] (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 an energy storage unit 10 and a bus bar unit 400 removed from a case body 610. Fig. 2 is an exploded perspective view of the bus bar unit 400 according to the embodiment. Fig. 3 is a perspective view of a bus bar 300, a spacer 200, and two energy storage elements 100 according to the embodiment. In Fig. 3, the bus bar holder 401 is not shown. The two energy storage elements 100 shown in Fig. 3 are adjacent to each other in the Y-axis direction with the spacer 200 sandwiched between them. When describing these two energy storage elements 100 separately, the energy storage element 100 in the negative Y-axis direction will be referred to as a first energy storage element 100A, and the energy storage element 100 in the positive Y-axis direction will be referred to as a second energy storage element 100B. The first energy storage element 100A and the second energy storage element 100B are two energy storage elements 100 adjacent to each other in the Y-axis direction that are arbitrarily selected from the plurality of energy storage elements 100 (see FIG. 1 ) included in the energy storage device 1. The Y-axis direction is an example of a first direction.

[0025] 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 mobile 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 1 can also be used as a stationary battery for home or business use.

[0026] 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.

[0027] 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 outside 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. The spacer 200 according to this embodiment includes a first opposing portion 210 (see FIG. 3). The first opposing portion 210 functions as a portion that guides the bus bar 300 to an appropriate position. The configuration of the bus bar 300 and its surroundings will be described later with reference to FIGS. 4 to 7.

[0028] The energy storage unit 10 has a generally 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 plurality of energy storage elements 100 included in the energy storage unit 10 are electrically connected by a plurality of bus bars 300.

[0029] 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.

[0030] 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. 3 , 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). For example, the electrode assembly may be a wound electrode assembly formed by winding an electrode plate 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.

[0031] 3, 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.

[0032] The energy storage element 100 includes terminals 140 arranged in the Z-axis direction. The Z-axis direction is an example of a second direction. The terminals 140 are 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. Hereinafter, when distinguishing between the negative electrode terminal 140 and the positive electrode terminal 140, the negative electrode terminal 140 will be referred to as a negative electrode terminal 141, and the positive electrode terminal 140 will be referred to as a positive electrode terminal 142.

[0033] The negative electrode terminal 141 has a terminal body 141a made of aluminum or an aluminum alloy and a shaft body made of copper or a copper alloy. The shaft body is joined to the terminal body 141a while passing through the terminal body 141a, and the end of the shaft body protrudes slightly from the upper surface of the terminal body 141a (the surface facing the positive direction of the Z axis; the same applies below). This forms a terminal protrusion 141b on the terminal body 141a due to the end. The positive electrode terminal 142 is made of aluminum or an aluminum alloy and has a flat upper surface.

[0034] In this embodiment, as shown in FIG. 3 , the terminal 140 included in the first energy storage element 100A is referred to as the first terminal 140A, and the terminal 140 included in the second energy storage element 100B is referred to as the second terminal 140B. That is, the first energy storage element 100A has two first terminals 140A, that is, a negative electrode terminal 141 and a positive electrode terminal 142, and the second energy storage element 100B has two second terminals 140B, that is, a negative electrode terminal 141 and a positive electrode terminal 142. When the first energy storage element 100A and the second energy storage element 100B are aligned in the Y-axis direction, the first terminal 140A and the second terminal 140B are aligned in the Y-axis direction. In this state, one of the first terminal 140A and the second terminal 140B is the negative electrode terminal 141, and the other is the positive electrode terminal 142. FIG. 3 shows that a negative electrode terminal 141 serving as a first terminal 140A and a positive electrode terminal 142 serving as a second terminal 140B are connected by a bus bar 300.

[0035] As shown in FIG. 3 , the bus bar 300 electrically and mechanically connects the first terminal 140A and the second terminal 140B 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 bonding plate portion 311 and a second bonding plate portion 312, each of which is joined to the terminal 140. As shown in FIG. 3 , the first bonding plate portion 311 and the second bonding plate portion 312 are arranged separately in the X-axis direction. The terminal protrusion 141b of the first terminal 140A is arranged between the first bonding plate portion 311 and the second bonding plate portion 312. 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.

[0036] The intermediate connection portion 350 is a plate-like portion that electrically and mechanically connects the first terminal connection portion 310 and the second terminal connection portion 320. In the present embodiment, the intermediate connection portion 350 is integral with the first terminal connection portion 310 and the second terminal connection portion 320. More specifically, the first terminal connection portion 310 is disposed on one side of the second terminal connection portion 320 in the Y-axis direction (in the present embodiment, the negative Y-axis direction). The intermediate connection portion 350 is connected to the end of the first terminal connection portion 310 on the other side in the Y-axis direction (in the present embodiment, the end on the positive Y-axis direction). Furthermore, the intermediate connection portion 350 is connected to the end on the other side of the second terminal connection portion 320. In other words, the intermediate connection portion 350 connects the end of the first terminal connection portion 310 in the positive Y-axis direction and the end of the second terminal connection portion 320 in the positive Y-axis direction.

[0037] The bus bar 300 shown in Figure 3 and other figures is an example of a bus bar that electrically and mechanically connects two adjacent energy storage elements 100 in the Y-axis direction. In other words, the configuration of the bus bar that electrically and mechanically connects the two energy storage elements 100 may be different from the configuration of the bus bar 300 shown in Figure 3 and other figures. For example, the two energy storage elements 100 may be electrically and mechanically connected by a bus bar that is generally flat.

[0038] The case 600 is a container having a substantially rectangular parallelepiped (box-like) shape that houses the energy storage unit 10. The rectangular parallelepiped here refers to a hexahedron with all faces formed of rectangles or squares. 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, aluminum alloy, stainless steel, iron, or plated steel sheet. In this embodiment, the case 600 is formed from aluminum die-casting (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.

[0039] 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.

[0040] The busbar unit 400 includes a plurality of busbars 300, a busbar holder 401 that holds the busbars 300, and a wiring substrate 500. The busbar unit 400 is disposed opposite the energy storage unit 10 in the Z-axis direction. The busbar holder 401 is a member formed of an insulating material such as resin, and includes a plurality of busbar accommodating sections 405 that accommodate the busbars 300. The busbar accommodating sections 405 are box-shaped sections that accommodate and hold the busbars 300 with their lower surfaces (surfaces facing the negative Z-axis direction) exposed. In this embodiment, as shown in FIGS. 1 and 2 , two energy storage elements 100 adjacent 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 busbars 300. Each of the plurality of busbars 300 is held in a busbar accommodating section 405 located at a position corresponding to the busbar 300. In this embodiment, a bus bar 382 is joined to the negative electrode terminal 141 of the energy storage element 100 at the end of the energy storage unit 10 facing in the positive direction of the Y axis, and a bus bar 381 is joined to the positive electrode terminal 142 of the energy storage element 100 at the end of the energy storage unit 10 facing in the negative direction of the Y axis. These bus bars 382 and 381 are also held by a bus bar holder 401.

[0041] 2 , the bus bar 382 is provided with a negative electrode general terminal 392 that protrudes in the positive direction of the Z axis, and the bus bar 381 is provided with a positive electrode general terminal 391 that protrudes in the positive direction of the Z axis. The negative electrode general terminal 392 and the positive electrode 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 with 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.

[0042] As shown in FIG. 2 , the bus bar holder 401 includes a substrate support portion 490 that supports the wiring substrate 500 at the center in the X-axis direction. The wiring substrate 500 supported by the substrate support portion 490 includes a substrate formed of an insulating material and conductive wiring formed on the substrate. Multiple conductive members 590 are connected to the wiring substrate 500, and each of the multiple conductive members 590 is connected to one of the bus bars 300, 381, or 382. A connector 510 is connected to the end of the wiring substrate 500 in the positive direction of the Y-axis. A control device that controls the charging and discharging of the energy storage device 1 is connected to the connector 510, for example. The control device detects the voltages of the multiple energy storage elements 100 via the multiple conductive members 590 and the wiring substrate 500 and controls the charging and discharging of the multiple energy storage elements 100 based on the detection results. That is, in this embodiment, the conductive members 590 are terminals for voltage detection (detection terminals).

[0043] 2. Configuration of Bus Bar 300 and Its Surrounding Area Next, the configuration of bus bar 300 and its surrounding area will be described using Figures 4 to 7 in addition to Figures 1 to 3 described above. Below, attention is focused on one bus bar 300 that electrically connects two adjacent energy storage elements 100 (first energy storage element 100A and second energy storage element 100B), and the configuration of bus bar 300 and its surrounding area will be described.

[0044] FIG. 4 is an enlarged perspective view showing the configuration of the busbar 300 and its surroundings according to the embodiment. In FIG. 4, the busbar holder 401 is illustrated separated from the two energy storage elements 100 in the positive direction of the Z axis, and the busbar 300 is illustrated separated from the busbar holder 401 in the positive direction of the Z axis. In FIG. 4, the busbar holder 401 is illustrated cut in front of the busbar 300 (in the negative direction of the Y axis) to clearly show the configuration of the busbar accommodating portion 405. FIG. 5 is a perspective view showing the configuration of the busbar accommodating portion 405 according to the embodiment. In FIG. 5, the busbar accommodating portion 405 is illustrated as viewed obliquely from the rear (when the positive direction of the Y axis is defined as the rear). In FIG. 5, the busbar holder 401 is illustrated cut in the rear of the intermediate wall portion 411 (in the positive direction of the Y axis) to clearly show the configuration of the busbar accommodating portion 405. Fig. 6 is a plan view (viewed from the positive direction of the Z axis) showing the positional relationship between the first opposing portion 210, the second opposing portion 420, and the bus bar 300 according to the embodiment. Fig. 7 is a cross-sectional view showing the positional relationship between the first opposing portion 210, the second opposing portion 420, and the bus bar 300 according to the embodiment. Fig. 7 simply illustrates the cross section taken along line VII-VII in Fig. 6. Fig. 7 simply illustrates the side views of the two energy storage elements 100, rather than cross sections.

[0045] As shown in FIGS. 4 to 7 , the busbar holder 401 includes a busbar accommodating portion 405 that accommodates the busbar 300. The busbar 300 accommodated in the busbar accommodating portion 405 is located between a pair of sidewalls 417 that face each other in the Y-axis direction. In this embodiment, the sidewalls 417 include a first sidewall 417a (see FIG. 5 ) and a second sidewall 417b (see FIG. 4 ). The first sidewall 417a is disposed in the negative direction of the Y-axis of the busbar 300 shown in FIG. 4 , and the second sidewall 417b is disposed in the positive direction of the Y-axis of the busbar 300. In other words, in this embodiment, two busbar accommodating portions 405 adjacent to each other in the Y-axis direction are separated by two walls (the first sidewall 417a and the second sidewall 417b) that are adjacent to each other in the Y-axis direction. This is not essential, and two busbar accommodating portions 405 adjacent to each other in the Y-axis direction may be separated by a single wall.

[0046] The bus bar 300 accommodated in the bus bar accommodating portion 405 is located between an outer wall portion 419 located in the positive direction of the X axis and an inner wall portion 418 located in the negative direction of the X axis. That is, in this embodiment, the bus bar accommodating portion 405 is configured so that the bus bar 300 accommodated in the bus bar accommodating portion 405 is surrounded by a pair of side walls 417, an inner wall portion 418, and an outer wall portion 419.

[0047] More specifically, the busbar accommodating portion 405 includes a first accommodating portion 406 that accommodates the first terminal connection portion 310 of the busbar 300 and a second accommodating portion 407 that accommodates the second terminal connection portion 320 of the busbar 300. The first accommodating portion 406 and the second accommodating portion 407 are separated by an intermediate wall portion 411. The intermediate wall portion 411 includes a second opposing portion 420. The second opposing portion 420 is a part of the intermediate wall portion 411 and is a portion between a pair of slits 425 extending from an edge of the intermediate wall portion 411 (an edge in the negative Z-axis direction in this embodiment). That is, one end of the second opposing portion 420 (an end in the positive Z-axis direction in this embodiment) is fixed to the intermediate wall portion 411. The other end of the second opposing portion 420 (an end in the negative Z-axis direction in this embodiment) is not fixed to the intermediate wall portion 411. Therefore, the second opposing portion 420 is easily deformed to warp in the Y-axis direction.

[0048] The spacer 200, which faces the bus bar holder 401 in the Z-axis direction and is arranged alongside the energy storage device 100 in the Y-axis direction, includes a first opposing portion 210. Specifically, the spacer 200 includes a spacer main body 201 facing the energy storage device 100 in the Y-axis direction and a first opposing portion 210 protruding from the spacer main body 201 in the positive direction of the Z-axis. In this embodiment, the spacer 200 further includes a spacer bottom wall 203 facing the bottom surface 113 of the energy storage device 100 and a pair of spacer side wall portions 202 facing the pair of short side surfaces 112 of the energy storage device 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 device 100. The spacer 200 further includes a protrusion 230 that is inserted into an attachment portion 430 of the bus bar holder 401. The protrusions 230 are provided to protrude in the positive direction of the Z axis from the spacer main body 201. The protrusions 230 of each of the plurality of spacers 200 are inserted into the attachment portions 430 that are arranged at positions corresponding to the protrusions 230, thereby attaching the bus bar holder 401 to the energy storage unit 10. In this state, the movement of the bus bar holder 401 as a whole relative to the energy storage unit 10, that is, movement parallel to the XY plane and movement in the Z axis direction, is restricted.

[0049] As described above, when the busbar holder 401 is attached to the energy storage unit 10, the first opposing portion 210 faces the second opposing portion 420 of the busbar holder 401 in the Y-axis direction (see FIGS. 6 and 7 ). Specifically, movement of the busbar holder 401 relative to the spacer 200 in the Y-axis direction is limited, for example, by inserting the protrusion 230 of the spacer 200 into the attachment portion 430 of the busbar holder 401. In this state, as shown in FIGS. 6 and 7 , the first opposing portion 210 of the spacer 200 is positioned in the negative Y-axis direction of the second opposing portion 420 of the busbar holder 401 and is in contact with the second opposing portion 420. As a result, the second opposing portion 420 deforms so as to warp in the positive Y-axis direction, for example, as shown in FIG. 7 , and comes into contact with a portion of the busbar 300. Accordingly, the busbar 300 is guided to a predetermined position in the Y-axis direction. That is, the bus bar 300 is guided by the first opposing portion 210 and the second opposing portion 420 to a predetermined position based on the spacer 200 (see FIGS. 6 and 7 ) located between the first energy storage element 100A and the second energy storage element 100B. As a result, the bus bar 300 is guided to positions suitable for joining to the first terminal 140A and the second terminal 140B, respectively. With the bus bar 300 guided to a position suitable for joining, the bus bar 300 and the first terminal 140A and the second terminal 140B are joined by laser welding or the like. As a result, the bus bar 300 is joined to the terminal 140 of the energy storage element 100 with high precision.

[0050] 4 , the intermediate connection portion 350 of the bus bar 300 includes a first intermediate portion 351, a second intermediate portion 352, and a third intermediate portion 355. The first intermediate portion 351 is connected to the first terminal connection portion 310 and extends in the Z-axis direction. The second intermediate portion 352 is connected to the second terminal connection portion 320 and extends in the Z-axis direction. The third intermediate portion 355 connects the first intermediate portion 351 and the second intermediate portion 352.

[0051] When the busbar 300 configured in this manner is guided to a position suitable for joining with the terminal 140 as described above, the second intermediate portion 352 of the busbar 300 is positioned close to or in contact with the second side wall portion 417b (see FIG. 7). At this time, the first intermediate portion 351 of the busbar 300 is positioned close to or in contact with the intermediate wall portion 411 (see FIG. 7). In other words, in this embodiment, movement of the busbar 300 in the positive direction of the Y axis is limited by at least one of the second side wall portion 417b and the intermediate wall portion 411 provided on the busbar holder 401. Furthermore, in this state, movement of the busbar 300 in the positive direction of the Z axis is also limited.

[0052] Specifically, the busbar holder 401 includes a first protrusion 415 provided on the intermediate wall 411 and protruding in the negative Y-axis direction, and a second protrusion 416 provided on the side wall 417 (second side wall 417b) and protruding in the negative Y-axis direction (see FIGS. 4 and 7 ). As shown in FIGS. 6 and 7 , when the busbar 300 is guided to an appropriate position in the Y-axis direction, the first protrusion 415 and the second protrusion 416 each face the busbar 300 in the Z-axis direction. Specifically, the first protrusion 415 faces the first intermediate portion 351 of the busbar 300 in the Z-axis direction, and the second protrusion 416 faces the second intermediate portion 352 of the busbar 300 in the Z-axis direction. This restricts movement of the busbar 300 in the positive Z-axis direction. In other words, movement of the busbar 300 in the negative Y-axis direction is restricted by the first opposing portion 210 (via the second opposing portion 420). Therefore, it is difficult for the bus bar 300 to move in the positive direction of the Z axis to avoid interference with the first protrusion 415 and the second protrusion 416 (i.e., movement in the negative direction of the Y axis). This limits the movement of the bus bar 300 in the positive direction of the Z axis. As a result, the bus bar 300 is joined to the terminal 140 of the energy storage element 100 with greater precision.

[0053] As described above, the energy storage device 1 according to this embodiment includes the first energy storage element 100A, the spacer 200, the bus bar 300, and the bus bar holder 401. The first energy storage element 100A and the spacer 200 are arranged side by side in the Y-axis direction. The first energy storage element 100A includes the first terminal 140A arranged in the Z-axis direction intersecting the Y-axis direction. The bus bar 300 is joined to the first terminal 140A. The spacer 200 includes the first opposing portion 210. The bus bar holder 401 includes the second opposing portion 420 that faces the first opposing portion 210 in the Y-axis direction. The second opposing portion 420 is arranged between the first opposing portion 210 and a portion of the bus bar 300 in the Y-axis direction.

[0054] According to this configuration, the first opposing portion 210 of the spacer 200 faces the second opposing portion 420 of the busbar holder 401 in the arrangement direction (Y-axis direction) of the first energy storage device 100A and the spacer 200. Furthermore, the second opposing portion 420 is disposed between the first opposing portion 210 and a portion of the busbar 300. Specifically, in the present embodiment, the second opposing portion 420 is disposed between the first opposing portion 210 and a second terminal connection portion 320 (see FIGS. 4 and 6 ), which is a portion of the busbar 300. Therefore, the first opposing portion 210 of the spacer 200 can limit movement of the busbar 300 in the Y-axis direction (movement in the negative Y-axis direction in the present embodiment) via the second opposing portion 420. Therefore, the first opposing portion 210 of the spacer 200 can guide the busbar 300 to a position suitable for joining the busbar 300 and the first terminal 140A. As a result, the busbar 300 can be joined to the first terminal 140A with high precision. Therefore, the energy storage device 1 according to this embodiment is an energy storage device with improved reliability.

[0055] More specifically, spacer 200, which includes first opposing portion 210 that guides the placement position of bus bar 300, is placed in contact with first energy storage element 100A, thereby more reliably guiding bus bar 300 to a position suitable for joining with first terminal 140A of first energy storage element 100A.

[0056] In the energy storage device 1 according to this embodiment, the first opposing portion 210 comes into contact with the second opposing portion 420 in the Y-axis direction. The second opposing portion 420 is fixed to the bus bar holder 401 at one end thereof in one direction intersecting with the Y-axis direction (in this embodiment, the end in the positive Z-axis direction), and is not fixed at the other end thereof in the one direction (in this embodiment, the end in the negative Z-axis direction).

[0057] As described above, in the present embodiment, second opposing portion 420 has a fixed end that is fixed to a portion of busbar holder 401 other than second opposing portion 420, and a free end opposite to the fixed end. Therefore, by coming into contact with first opposing portion 210 in the Y-axis direction, second opposing portion 420 can efficiently displace or deform in a direction toward that portion of busbar 300. As a result, second opposing portion 420 can efficiently guide busbar 300 to an appropriate position.

[0058] In the energy storage device 1 according to the present embodiment, the bus bar holder 401 includes an intermediate wall portion 411 located between the first opposing portion 210 and a part of the bus bar 300 in the Y-axis direction. The second opposing portion 420 is a part of the intermediate wall portion 411.

[0059] In this way, since the second opposing portion 420 is provided as part of the intermediate wall portion 411, the mechanical strength of the second opposing portion 420 is improved. Therefore, for example, the second opposing portion 420 can be deformed more greatly as needed. This makes it easier to expand the range in which the bus bar 300 can be arranged (the range in the Y-axis direction) that can be guided by the first opposing portion 210 and the second opposing portion 420.

[0060] More specifically, the energy storage device 1 further includes a second energy storage element 100B (see FIGS. 3 and 4). The second energy storage element 100B includes a second terminal 140B arranged in the Z-axis direction. The spacer 200 is located between the first energy storage element 100A and the second energy storage element 100B in the Y-axis direction. The bus bar 300 is joined to the first terminal 140A and the second terminal 140B.

[0061] In this way, when attention is focused on two energy storage elements 100 adjacent to each other in the Y-axis direction with spacer 200 sandwiched therebetween, the movement of bus bar 300 for connecting the two energy storage elements 100 is restricted by first opposing portion 210 of spacer 200. As a result, bus bar 300 is positioned in a position suitable for joining to terminals 140 of the two energy storage elements 100, respectively.

[0062] In the energy storage device 1 according to the present embodiment, the first opposing portion 210 is aligned with the first terminal 140A in the Y-axis direction. That is, when viewed from the Y-axis direction, at least a portion of the first opposing portion 210 overlaps with the first terminal 140A. More preferably, when viewed from the Y-axis direction, the entire area of ​​the first opposing portion 210 in the X-axis direction overlaps with the first terminal 140A.

[0063] According to this configuration, the first opposing portion 210 is disposed within the width of the first terminal 140A in the X-axis direction, which intersects with the Y-axis direction and the Z-axis direction. Therefore, the bus bar holder 401 can be provided with the second opposing portion 420 without increasing the width of the bus bar holder 401 in the X-axis direction.

[0064] In the energy storage device 1 according to this embodiment, the second opposing portion 420 has a protrusion 422 that protrudes toward a portion of the bus bar 300, as shown in FIGS. 5 to 7 . The bus bar 300 has a recess 322 into which at least a portion of the protrusion 422 is inserted, as shown in FIGS. 6 and 7 . In this embodiment, the second opposing portion 420 has an opposing main body portion 421 that extends in the Z-axis direction, and the protrusion 422 provided at the end of the opposing main body portion 421 in the negative Z-axis direction. The bus bar 300 has a recess 322 that is recessed in the positive Y-axis direction, at the end of the second terminal connection portion 320 in the negative Y-axis direction (see FIG. 6 ).

[0065] With this configuration, at least a portion of the protrusion 422 of the opposing portion is inserted into the recess 322 of the busbar 300 in the Y-axis direction. This limits movement of the busbar 300 in the X-axis direction, which intersects with the Y-axis and Z-axis directions. That is, the first opposing portion 210 can also limit movement of the busbar 300 in the X-axis direction via the second opposing portion 420. As a result, the busbar 300 is more reliably guided to an appropriate position.

[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. For example, 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. In other words, 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 first opposing portion 210 of the spacer 200 and the second opposing portion 420 of the bus bar holder 401 can guide the bus bar 300, which is positioned to overlap the spacer 200 in a plan view, to an appropriate position.

[0068] The first opposing portion 210 of the spacer 200 does not need to be provided so as to protrude in the positive direction of the Z axis from the spacer main body 201. For example, a part of the end portion of the spacer main body 201 in the positive direction of the Z axis may function as the first opposing portion 210. In other words, in the spacer 200, the first opposing portion 210 does not need to be provided in a manner that allows it to be clearly distinguished from portions other than the first opposing portion 210.

[0069] The second opposing portion 420 of the bus bar holder 401 does not need to include the convex portion 422 (see FIGS. 5 to 7). There are no particular limitations on the shape and size of the second opposing portion 420 as long as it is configured to deform in the Y-axis direction upon receiving a force from the first opposing portion 210.

[0070] The bus bar 300 does not need to include the recess 322 (see FIGS. 6 and 7). For example, the edge of the second terminal connection portion 320 (see FIG. 4) in the negative Y-axis direction may be a straight line parallel to the X-axis direction in plan view. The edge may also have a shape that protrudes in the negative Y-axis direction in plan view. In either case, the edge comes into contact with the second opposing portion 420, thereby guiding the bus bar 300 to an appropriate position.

[0071] The second opposing portion 420 of the busbar holder 401 may be disposed in the negative Y-axis direction of the first opposing portion 210 of the spacer 200. In this case, the second opposing portion 420 may contact the end of the first intermediate portion 351 of the busbar 300 in the negative Z-axis direction (or the end of the first terminal connection portion 310 in the positive Y-axis direction). In other words, the positional relationship in the Y-axis direction between the first opposing portion 210, the second opposing portion 420, and a portion of the busbar 300 (a portion facing the second opposing portion 420) may be reversed from the positional relationship shown in FIG. 7 . Even in this case, the busbar 300 is guided to a predetermined position relative to the spacer 200. In other words, the first opposing portion 210 can guide the busbar 300, via the second opposing portion 420, to a position suitable for joining with the terminals 140 of one or more energy storage elements 100.

[0072] The second opposing portion 420 of the bus bar holder 401 may be fixed to the intermediate wall portion 411 not at one end in the Z axis direction but at, for example, one end in the X axis direction. Even in this case, the second opposing portion 420 can be deformed so as to warp in the positive direction of the Y axis by coming into contact with the first opposing portion 210 located in the negative direction of the Y axis. This allows the first opposing portion 210 to guide the bus bar 300 to an appropriate position via the second opposing portion 420.

[0073] The bus bar holder 401 is attached to the energy storage unit 10 by inserting the protrusions 230 of the spacer 200 into the attachment portions 430 of the bus bar holder 401. However, there are no particular limitations on the method of attaching the bus bar holder 401 to the energy storage unit 10. For example, the bus bar holder 401 may be attached to the energy storage unit 10 by fixing the bus bar holder 401 to the case main body 610 (see FIG. 1 ) by adhesive bonding, welding, fitting, or bolting. Even in this case, the bus bar 300 is guided to a predetermined position based on the spacer 200 aligned with the energy storage element 100 in the Y-axis direction. In other words, the bus bar 300 is guided to a position suitable for joining with the terminals 140 of the energy storage element 100.

[0074] The configuration of busbar accommodating portion 405 may be different from the configurations shown in Figures 2, 4, 5, and 7. For example, busbar accommodating portion 405 does not have to cover the entire circumference of busbar 300 in a plan view. In other words, busbar accommodating portion 405 does not have to include at least one of the pair of side wall portions 417, inner wall portion 418, and outer wall portion 419. However, from the perspective of improving the reliability of insulation between busbar 300 and other members (or people), for example, busbar accommodating portion 405 is preferably configured to cover the entire circumference of busbar 300 in a plan view.

[0075] The busbar accommodating portion 405 does not need to include the intermediate wall portion 411. Even if the busbar accommodating portion 405 does not include the intermediate wall portion 411, the busbar holder 401 includes a portion that supports the second opposing portion 420, and therefore the first opposing portion 210 can guide the busbar 300 to an appropriate position via the second opposing portion 420.

[0076] The busbar unit 400 does not need to include the wiring substrate 500. For example, a coated electric wire for voltage detection may be electrically connected to each of the plurality of busbars 300. In other words, the voltages of the plurality of energy storage elements 100 may be detected via the plurality of coated electric wires.

[0077] The energy storage device 1 does not need to include the case 600. For example, a structure including the energy storage elements 100, the spacers 200, the bus bars 300, and the bus bar holders 401 may be housed in some kind of device, a rack, or the like as the energy storage device 1.

[0078] Any combination of the components of the above-described embodiment and its modifications is also included within the scope of the present invention.

[0079] 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.

[0080] REFERENCE SIGNS LIST 1 Energy storage device 100 Energy storage element 100A First energy storage element 100B Second energy storage element 140 Terminal 140A First terminal 140B Second terminal 200, 250 Spacer 201 Spacer main body 210 First opposing portion 300, 381, 382 Bus bar 310 First terminal connection portion 320 Second terminal connection portion 322 Recess 401 Bus bar holder 405 Bus bar accommodating portion 411 Intermediate wall portion 415 First protruding portion 416 Second protruding portion 417 Side wall portion 417a First side wall portion 417b Second side wall portion 418 Inner wall portion 419 Outer wall portion 420 Second opposing portion 421 Opposing main body portion 422 Convex portion 425 Slit

Claims

1. An energy storage device comprising: a first storage element, a spacer, a busbar, and a busbar holder, wherein the first storage element and spacer are arranged side by side in a first direction, the first storage element has a first terminal arranged in a second direction intersecting the first direction, the busbar is joined to the first terminal, the spacer has a first opposing portion, and the busbar holder has a second opposing portion opposing the first opposing portion in the first direction, the second opposing portion being arranged between the first opposing portion and a portion of the busbar in the first direction.

2. The energy storage device according to claim 1, wherein the first opposing portion is in contact with the second opposing portion in the first direction, and the second opposing portion is fixed to the bus bar holder at one end on one side in a direction intersecting with the first direction, and is not fixed at the other end on the other side in the one direction.

3. The energy storage device according to claim 2, wherein the bus bar holder includes an intermediate wall portion located between the first opposing portion and the portion of the bus bar in the first direction, and the second opposing portion is a part of the intermediate wall portion.

4. The energy storage device according to any one of claims 1 to 3, further comprising a second storage element, the second storage element comprising a second terminal arranged in the second direction, the spacer being positioned between the first storage element and the second storage element in the first direction, and the bus bar being joined to the first terminal and the second terminal.

5. The energy storage device according to any one of claims 1 to 3, wherein the first opposing portion is aligned with the first terminal in the first direction.

6. The energy storage device according to any one of claims 1 to 3, wherein the second opposing portion has a convex portion that protrudes toward the portion of the bus bar, and the bus bar has a concave portion into which at least a portion of the convex portion is inserted.

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