Power storage device

Abstract

This power storage device comprises: a power storage unit including a power storage element; and a wiring board disposed in a first direction of the power storage unit. The wiring board comprises: a substrate body on which a plurality of wires are disposed; and a plurality of connection pieces connecting the substrate body and the power storage unit. The power storage unit comprises a restricting part disposed on the outer periphery of the wiring board. The restricting part is connected to a peripheral edge part of the wiring board to restrict the movement of the wiring board in a direction crossing 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 connection module. The connection module is attached to a group of energy storage elements in which a plurality of energy storage elements are arranged in a row, and connects the plurality of energy storage elements in series. The connection module includes a flexible printed circuit (FPC), a plurality of bus bars connected to the FPC, and a resin protector that holds the bus bars and the FPC. The FPC includes an FPC main body in the shape of a rectangular strip. The resin protector includes an FPC holding portion that holds the FPC main body. The FPC main body has positioning holes, and the FPC holding portion has positioning protrusions that are inserted into the positioning holes of the FPC main body.

[0003] Japanese Patent Application Laid-Open No. 2020-87665

[0004] In the connection module included in the conventional battery module, the FPC body is positioned relative to the resin protector by inserting a positioning protrusion on the FPC holding portion of the resin protector into a positioning hole in the FPC body. However, the FPC body includes a conductive path formed by copper foil and an insulating resin film covering both sides of the conductive path. Therefore, the positioning hole cannot be located in the area of ​​the FPC body where the conductive path is located. As a result, a problem occurs in that the FPC body becomes larger in size in order to secure an area for the positioning hole.

[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 an electricity storage device that can prevent an increase in the size of a wiring board.

[0006] An energy storage device according to one aspect of the present invention comprises an energy storage unit having an energy storage element, and a wiring board arranged in a first direction of the energy storage unit, the wiring board having a substrate main body on which a plurality of wires are arranged, and a plurality of connection pieces connecting the substrate main body and the energy storage unit, the energy storage unit having a limiting portion arranged on the outer periphery of the wiring board, the limiting portion contacting the peripheral portion of the wiring board to limit movement of the wiring board in a direction intersecting the first direction.

[0007] According to the electricity storage device of the present invention, an increase in the size of the wiring board is suppressed.

[0008] FIG. 1 is a perspective view showing a configuration of an energy storage device according to an embodiment. FIG. 2 is a perspective view showing a configuration of a wiring board and a bus bar unit according to an embodiment. FIG. 3 is a perspective view of a bus bar according to an embodiment and two energy storage elements connected by the bus bar. FIG. 4 is a plan view showing an example layout of a plurality of limiting portions according to an embodiment. FIG. 5A is a plan view showing an example layout of wiring in a portion of a wiring board in the negative Y-axis direction. FIG. 5B is a plan view showing an example layout of wiring in a portion of a wiring board in the positive Y-axis direction. FIG. 6 is a perspective view showing a portion of a bus bar unit and a wiring board according to an embodiment. FIG. 7A is a first partially enlarged view showing a position of a limiting portion relative to the wiring board according to the embodiment. FIG. 7B is a second partially enlarged view showing a position of a limiting portion relative to the wiring board according to the embodiment. FIG. 7C is a third partially enlarged view showing a position of a limiting portion relative to the wiring board according to the embodiment. FIG. 8 is a cross-sectional view of a limiting portion according to an embodiment. FIG. 9 is a cross-sectional view of a protrusion according to an embodiment. FIG. 10 is a cross-sectional view of a limiting portion according to a first modified example of the embodiment. FIG. 11 is a plan view showing a portion of a wiring board according to a second modified example of the embodiment.

[0009] (1) An energy storage device according to one aspect of the present invention comprises an energy storage unit having an energy storage element, and a wiring board arranged in a first direction of the energy storage unit, the wiring board having a substrate body on which a plurality of wires are arranged, and a plurality of connection pieces connecting the substrate body and the energy storage unit, the energy storage unit having a limiting portion arranged on the outer periphery of the wiring board, the limiting portion contacting a peripheral portion of the wiring board to limit movement of the wiring board in a direction intersecting the first direction.

[0010] In a power storage device according to one embodiment of the present invention, a limiting portion is disposed on the outer periphery of a wiring substrate. This eliminates the need to provide a through-hole or the like in the substrate body through which a portion for limiting the movement of the wiring substrate penetrates. Therefore, for example, wiring can be disposed over a wide area of ​​the substrate body when viewed from a first direction (plan view). This prevents the wiring substrate from becoming large.

[0011] (2) In the energy storage device described in (1) above, the wiring board may further include a connector provided at an end of the board body in a second direction intersecting the first direction, and the limiting portion may be positioned closer to the connector than the center of the board body in the second direction.

[0012] In the area of ​​the substrate body near the connector, the wiring density is relatively high, making it difficult to arrange through holes or the like in the substrate body. In this regard, according to the energy storage device described in (2) above, the limiting portion is arranged in a position near the connector relative to the center of the substrate body and on the outer periphery of the wiring substrate. Therefore, in the area of ​​high wiring density, the limiting portion can restrict the movement of the substrate body without interfering with the arrangement of the wiring.

[0013] (3) In the energy storage device described in (2) above, the energy storage unit may include a plurality of limiting portions, and the number of limiting portions among the plurality of limiting portions that are positioned closer to the connector than the center of the substrate body in the second direction may be greater than the number of limiting portions that are positioned farther from the connector than the center of the substrate body in the second direction.

[0014] According to the energy storage device described in (3) above, a plurality of limiting portions are arranged on the outer periphery of the wiring substrate. Furthermore, a greater number of the limiting portions are arranged in positions where the wiring density is high so as not to interfere with the arrangement of the wiring. This makes it possible to more reliably and / or more accurately limit the movement of the wiring substrate while suppressing an increase in the size of the substrate.

[0015] (4) In the energy storage device described in any one of (1) to (3) above, the peripheral portion of the wiring substrate may include a first peripheral portion and a second peripheral portion, the first peripheral portion extending in a second direction intersecting the first direction, the second peripheral portion extending in a third direction intersecting the first direction and the second direction, and the limiting portion may be positioned along the first peripheral portion and the second peripheral portion.

[0016] According to the power storage device described in (4) above, the movement of the substrate body in the third direction is restricted by the contact of the limiting portion with the first peripheral edge portion, and the movement of the substrate body in the second direction is restricted by the contact of the limiting portion with the second peripheral edge portion, thereby enabling the movement of the substrate body to be restricted more efficiently by a single limiting portion.

[0017] (5) In the energy storage device described in any one of (1) to (4) above, the energy storage unit may include a bus bar connected to the energy storage element and one of the plurality of connection pieces, and a bus bar case that holds the bus bar and is arranged in the first direction of the energy storage element, and the limiting portion may be arranged in the bus bar case.

[0018] According to the energy storage device described above in (5), the bus bar case disposed close to the wiring board in the first direction is used as a base member of the restricting portion, thereby enabling the restricting portion to restrict movement of the wiring board more stably.

[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 the 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 wiring board 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] First, a schematic configuration of an energy storage device 1 according to the present embodiment will be described. FIG. 1 is a perspective view showing the configuration of the energy storage device 1 according to the embodiment. FIG. 1 illustrates a state in which an energy storage unit 50 is removed from a case body 610 and the energy storage unit 50 is separated into an energy storage element array 10 and a bus bar unit 400. FIG. 2 is a perspective view showing the configuration of a wiring board 500 and a bus bar unit 400 according to the embodiment. FIG. 2 illustrates the wiring board 500 and the multiple bus bars 300 separated from a bus bar case 401. FIG. 3 is a perspective view of a bus bar 300 according to the embodiment and two energy storage elements 100 connected by the bus bar 300. The two energy storage elements 100 shown in FIG. 3 are two energy storage elements 100 adjacent to each other in the Y-axis direction in the energy storage element array 10.

[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 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.

[0024] 1 , the energy storage device 1 includes an energy storage unit 50, a wiring board 500 arranged in the positive direction of the Z axis of the energy storage unit 50, and a case 600 that houses the energy storage element array 10 and the like. The positive direction of the Z axis is an example of a first direction. The energy storage device 1 also includes external terminals (positive external terminal and negative external terminal) for electrically connecting to an external device, but these are not shown or described here. 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 element array 10.

[0025] The energy storage unit 50 includes an energy storage element array 10 and a bus bar unit 400 arranged in the positive direction of the energy storage element array 10 along the Z axis. The energy storage element array 10 is a battery module (battery assembly) having a plurality of energy storage elements 100. The energy storage element array 10 has a substantially rectangular parallelepiped shape elongated in the Y axis direction, with a plurality of (34 in this embodiment) energy storage elements 100 arranged in the Y axis direction. The rectangular parallelepiped here refers to a hexahedron with all faces formed as rectangles or squares. The Y axis direction is an example of a second direction. The plurality of energy storage elements 100 included in the energy storage element array 10 are electrically connected by a plurality of bus bars 300. The energy storage element array 10 may include spacers (not shown). Specifically, an inter-cell spacer may be arranged between two energy storage elements 100 arranged in the Y axis direction. End spacers may be arranged at both ends of the energy storage element array 10 in the Y axis direction. Each of these spacers may function as a cell holder for holding one or more energy storage elements 100 adjacent to the spacer.

[0026] In this embodiment, the energy storage element array 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 element array 10 may be restrained in the Y-axis direction by restraining members.

[0027] 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). The electrode assembly may be, for example, a wound type formed by winding an electrode plate and a separator, or a stacked type formed by stacking multiple flat 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 be a primary battery. The energy storage element 100 may be a battery using a solid electrolyte. The shape of the energy storage element 100 is not limited to the above-mentioned polygonal shape, and may be other shapes such as a polygonal column shape, a cylindrical shape, an elliptical column shape, or an oblong column shape.

[0028] As shown in Fig. 3, the container 110 is a rectangular parallelepiped case having a pair of long sides 111, a pair of short sides 112, a bottom surface 113, and a terminal arrangement surface 130. The terminal arrangement surface 130 is provided with a pair of terminals 140 and a gas exhaust valve 131. The container 110 is configured so that the interior can be sealed by accommodating an electrode assembly and the like inside the container body that forms the parts other than the terminal arrangement surface 130, and then welding the container body to a cover plate that forms the terminal arrangement surface 130. 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.

[0029] The terminals 140 are terminal members electrically connected to the electrode assembly housed in the container 110. In this embodiment, the terminals 140 are provided protruding from the terminal placement surface 130 in the positive direction of the Z axis. 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 the negative electrode terminal 140B, and the positive electrode terminal 140 will be referred to as the positive electrode terminal 140A. The terminals 140 are formed of a metal such as aluminum, an aluminum alloy, copper, or a copper alloy. FIG. 3 shows that the negative electrode terminal 140B of the energy storage element 100 in the negative direction of the Y axis and the positive electrode terminal 140A of the energy storage element 100 in the positive direction of the Y axis are connected by a bus bar 300.

[0030] The bus bar 300 according to this embodiment includes a first joint portion 310, a second joint portion 320, and a connecting plate portion 350. The first joint portion 310 and the second joint portion 320 are each a plate-shaped portion bonded to the upper surface of the terminal 140. The method for bonding the first joint portion 310 and the second joint portion 320 to the terminal 140 is not particularly limited, but laser welding, for example, may be used. The connecting plate portion 350 includes a first wall portion 370, a second wall portion 380, and a flat plate portion 360 connecting the first wall portion 370 and the second wall portion 380. The first joint portion 310 and the flat plate portion 360 are connected via the first wall portion 370. The second joint portion 320 and the flat plate portion 360 are connected via the second wall portion 380. In this embodiment, the flat plate portion 360 is disposed parallel to the Y-axis direction. The flat plate portion 360 is a portion to which a conductive member 580 connected to a wiring substrate 500 (described later) is bonded. Conductive member 580 is a member made of a conductive metal. There are no particular limitations on the method for joining conductive member 580 to bus bar 300. Welding such as laser welding, connection using screws, crimping, or the like can be used to join conductive member 580 to bus bar 300.

[0031] The shape of the bus bar 300 included in the energy storage device 1 is not limited to the shape shown in Fig. 3 etc. The bus bar 300 may have any shape and size that can electrically connect at least two energy storage elements 100 adjacent in the Y-axis direction. The bus bar 300 may be realized by, for example, a flat metal plate parallel to the XY plane.

[0032] The case 600 is a container having a substantially rectangular parallelepiped (box-shaped) shape that houses the energy storage element array 10. The case 600 is disposed outside the energy storage element array 10 and protects the energy storage element array 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 plated steel sheet. In this embodiment, the case 600 is formed by aluminum die-casting (aluminum die-casting). It is not essential that the case 600 be made of metal, and the case 600 may be formed from an insulating material such as a resin material.

[0033] As shown in FIG. 1 , the case 600 has a case body 610. The case 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 energy storage element array 10. The case body 610 includes a side wall portion 611 facing the energy storage element array 10 in the X axis direction, a side wall portion 612 facing the energy storage element array 10 in the Y axis direction, and a bottom wall portion 615 supporting the energy storage element array 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 body 610. The lid may include a terminal block on which external terminals (positive external terminal and negative external terminal) are arranged.

[0034] 2 , 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 faces the energy storage element array 10 in the positive direction of the Z axis of the energy storage element array 10. The busbar case 401 is a member formed of an insulating material such as resin, and includes a plurality of busbar accommodating portions 410 that accommodate the plurality of busbars 300, and a substrate support portion 420 that supports the wiring substrate 500.

[0035] The busbar accommodating portion 410 is a box-shaped portion that accommodates and holds the busbar 300 with the underside (the surface facing the negative Z-axis direction) of the busbar 300 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 busbar 300. That is, the multiple energy storage elements 100 included in the energy storage element array 10 are connected in series by the multiple busbars 300. In this embodiment, a busbar 382, ​​which is one of the multiple busbars 300, is joined to the negative electrode terminal 140B of the energy storage element 100 at the end of the energy storage element array 10 facing the positive Y-axis direction. A busbar 381, which is one of the multiple busbars 300, is joined to the positive electrode terminal 140A of the energy storage element 100 at the end of the energy storage element array 10 facing the negative Y-axis direction. These busbars 382 and 381 are also held in the busbar case 401. The bus bar 382 is electrically connected to a negative external terminal (not shown), and the bus bar 381 is electrically connected to a positive external terminal (not shown).

[0036] The board support portion 420 is a flat plate-shaped portion located in the center of the bus bar case 401 in the X-axis direction, and supports the wiring board 500 from the negative Z-axis direction. The board support portion 420 is provided with limiting portions 440. The limiting portions 440 are located on the outer periphery of the wiring board 500 in a plan view (when viewed from the positive Z-axis direction, the same applies below), and have the function of limiting the movement of the wiring board 500. The board support portion 420 also has protruding portions 490 that fix the wiring board 500. Details of the limiting portions 440 and the protruding portions 490 will be described later using FIGS. 4 to 9.

[0037] The wiring board 500 according to this embodiment is a flexible printed circuit (FPC). The wiring board 500 has a multilayer structure including a metal foil that forms wiring 530 (described later using FIGS. 5A and 5B ) and two insulating layers that sandwich the metal foil. Specifically, the wiring board 500 includes, for example, a base film, a copper foil that forms the wiring 530 and is disposed on the surface of the base film, and a coverlay that covers the copper foil. The base film and the coverlay are formed of an insulating resin. The thickness of the wiring board 500 is, for example, approximately 0.1 mm to 1 mm.

[0038] The wiring substrate 500 includes a substrate body 501 and connection pieces 510 that connect the substrate body 501 and the energy storage unit 50. The substrate body 501 has a U-shape that is elongated in the Y-axis direction, with the end portion in the positive Y-axis direction connected in a plan view. Multiple connection pieces 510 are provided at both ends of the substrate body 501 in the X-axis direction, aligned in the Y-axis direction. In this embodiment, the multiple connection pieces 510 are integrally provided with the substrate body 501. That is, the multiple connection pieces 510 are part of the FPC that forms the substrate body 501, and therefore are flexible. A conductive member 580 is connected to each of the multiple connection pieces 510, and each of the multiple conductive members 580 is connected to one bus bar 300, 381, or 382. Because the connection pieces 510 are flexible, they can deform to protect the connection portion with the connection object (such as the bus bar 300) if the connection object is misaligned. The wiring substrate 500 may include a conductive member 580. In this case, a portion of the wiring substrate 500 that is made up of the connection piece 510 and the conductive member 580 may be referred to as a "connection piece." In other words, the connection piece 510 may include the conductive member 580.

[0039] The wiring board 500 further includes a connector 590 connected to the end of the board body 501 in the positive direction of the Y axis. Specifically, the wiring board 500 includes a connecting portion 502 extending from the board body 501 in the positive direction of the Y axis, and the connector 590 is connected to the connecting portion 502. A control device that controls the charging and discharging of the energy storage device 1 is connected to the connector 590, for example. The control device detects the voltage of each of the multiple energy storage elements 100 via the multiple conductive members 580 and the wiring board 500, and controls the charging and discharging of the multiple energy storage elements 100 based on the detection results. In other words, in this embodiment, the conductive member 580 is a terminal (detection terminal) for voltage detection. The conductive member 580 is joined, by soldering or the like, to the wiring 530 exposed on a portion of the surface of the connecting piece 510 in the positive direction of the Z axis.

[0040] [2. Restriction Unit 440 and Surrounding Configuration] Next, the restriction unit 440 provided in the power storage device 1, which restricts the movement of the wiring substrate 500, and the surrounding configuration will be described using FIGS. 4 to 9 in addition to the above-described FIGS. 1 to 3 .

[0041] FIG. 4 is a plan view showing an example layout of a plurality of limiting portions 440 according to an embodiment. In FIG. 4, the approximate arrangement range of the bus bar case 401 and the energy storage unit 50 is indicated by a rectangular dashed line. In FIG. 4, a center line CL parallel to the X-axis direction and passing through the center of the substrate main body 501 in the Y-axis direction is indicated by a dashed line. FIG. 5A is a plan view showing an example layout of the wiring 530 in a portion of the wiring substrate 500 in the negative Y-axis direction. FIG. 5B is a plan view showing an example layout of the wiring 530 in a portion of the wiring substrate 500 in the positive Y-axis direction. In FIGS. 5A and 5B, the main body portion of the bus bar case 401 (portions other than the protrusions 490 and the limiting portions 440) is omitted from illustration. FIG. 6 is a perspective view showing a portion of the bus bar unit 400 and the wiring substrate 500 according to an embodiment. FIGS. 7A to 7C are first to third enlarged partial views showing the positions of the limiting portions 440 relative to the wiring substrate 500 according to an embodiment. 7A to 7C, the limiting portion 440 is patterned to make the position of the limiting portion 440 easier to recognize. Fig. 8 is a cross-sectional view of the limiting portion 440 according to the embodiment. Fig. 9 is a cross-sectional view of the convex portion 490 according to the embodiment. Fig. 8 shows a portion of the cross section taken along line VIII-VIII in Fig. 5B, and Fig. 9 shows a portion of the cross section taken along line IX-IX in Fig. 5A.

[0042] 4 to 6, the energy storage device 1 according to this embodiment includes a wiring board 500. The wiring board 500 is disposed in a bus bar case 401 included in the energy storage unit 50. Specifically, the wiring board 500 is disposed on a board support portion 420 of the bus bar case 401. The board support portion 420 according to this embodiment includes a limiting portion 440 disposed on the outer periphery of the wiring board 500. In this embodiment, a plurality of limiting portions 440 (seven in this embodiment) are provided on the board support portion 420 of the bus bar case 401.

[0043] The outer periphery of wiring substrate 500 is a portion or area surrounding wiring substrate 500 in a plan view. Restricting portion 440 arranged on the outer periphery of wiring substrate 500 can restrict movement of wiring substrate 500 by coming into contact with peripheral edge portion 505 of wiring substrate 500, as shown in Figures 6, 7A, 7B, 7C, and 8. In this way, restricting portion 440 can stabilize the position of wiring substrate 500 during manufacture or use of energy storage device 1.

[0044] In the energy storage device 1, the wiring substrate 500 may be arranged in a state where the peripheral edge 505 of the wiring substrate 500 is in contact with the limiting portion 440, or in a state where the peripheral edge 505 is not in contact with the limiting portion 440. In other words, the limiting portion 440 does not need to be in constant contact with the peripheral edge 505 of the wiring substrate 500. When the wiring substrate 500 attempts to move in a direction intersecting the Z-axis direction, if the limiting portion 440 is arranged in a position facing the peripheral edge 505 of the wiring substrate 500 in that direction and in close proximity to the peripheral edge 505, the movement of the wiring substrate 500 is restricted by the contact between the peripheral edge 505 and the limiting portion 440.

[0045] The energy storage device 1 according to this embodiment further includes a protrusion 490 as a portion that limits movement of the wiring board 500 relative to the bus bar case 401. Like the limiting portion 440, the protrusion 490 is provided on the board support portion 420 of the bus bar case 401. Unlike the limiting portion 440, the protrusion 490 limits movement of the wiring board 500 while passing through a through hole 509 provided in the wiring board 500. The board support portion 420 is provided with a plurality of protrusions 490, and these plurality of protrusions 490 are arranged in an area of ​​the wiring board 500 that is far from the connector 590.

[0046] More specifically, the wiring substrate 500 includes a substrate body 501 and a plurality of connection pieces 510 extending from the substrate body 501, with a conductive member 580 connected to each of the plurality of connection pieces 510. The wiring substrate 500 also includes a plurality of wirings 530 connected to the plurality of conductive members 580. As shown in FIGS. 5A and 5B , each of the plurality of wirings 530 is arranged extending in the Y-axis direction so as to connect the plurality of conductive members 580 to a connector 590. Therefore, the plurality of wirings 530 connected to different conductive members 580 are arranged side by side in the X-axis direction on the substrate body 501. In other words, on the wiring substrate 500, the wirings 530 are arranged extending from each of the plurality of connection pieces 510 arranged side by side in the Y-axis direction toward the connector 590. As a result, in the region of the substrate body 501 far from the connector 590, i.e., in the region of the substrate body 501 in the negative Y-axis direction, the density of the wirings 530 is relatively low, as shown in FIG. 5A . Therefore, the area of ​​the substrate body 501 where the wiring 530 is not arranged is relatively large. Therefore, in the area of ​​the substrate body 501 in the negative Y-axis direction, there is a high degree of freedom in the position of the through-hole 509 through which the convex portion 490 passes. Therefore, in this embodiment, a plurality of through-holes 509 are provided in an area of ​​the wiring substrate 500 far from the connector 590. As a result, the movement of the portion of the wiring substrate 500 included in that area is restricted by one or more convex portions 490.

[0047] More specifically, as shown in FIG. 9 , the convex portion 490 according to this embodiment includes a shaft portion 491 that passes through the through hole 509, and a head portion 492 that is disposed at the tip of the shaft portion 491 and has a larger outer diameter than the shaft portion 491. The convex portion 490 having such a configuration is formed, for example, by heat caulking the tip of the shaft portion 491. In a plan view, the head portion 492 is larger than the through hole 509. Therefore, the convex portion 490 can limit movement of the wiring substrate 500 in a direction intersecting the Z-axis direction and in a direction parallel to the Z-axis direction. In this embodiment, the convex portion 490 is an integral part of the bus bar case 401. However, the convex portion 490 that is separate from the bus bar case 401 may also be connected to the bus bar case 401. There are no particular limitations on the method for connecting the convex portion 490 to the bus bar case 401. The bus bar case 401 and the protrusion 490 may be connected by adhesion, welding, fitting, screw connection, or the like.

[0048] On the other hand, in the region of the substrate body 501 close to the connector 590, i.e., in the region of the substrate body 501 in the positive direction of the Y axis, the density of the wiring 530 is relatively high, as shown in FIG. 5B . Therefore, the region of the substrate body 501 where the wiring 530 is not arranged is relatively small. Therefore, there is almost no space to provide the through holes 509 in the region of the substrate body 501 in the positive direction of the Y axis. In particular, it is difficult to provide the through holes 509 in the range where multiple connection pieces 510 are arranged in the Y axis direction. Therefore, in this embodiment, one or more limiting portions 440 are arranged on the outer periphery of the wiring substrate 500 in a planar view, rather than inside the wiring substrate 500. As a result, the movement of the wiring substrate 500 is restricted by the one or more limiting portions 440.

[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 an energy storage unit 50 including energy storage elements 100, and a wiring substrate 500 arranged in the positive direction of the Z axis of the energy storage unit 50. The wiring substrate 500 includes a substrate main body 501 on which a plurality of wires 530 are arranged, and a plurality of connection pieces 510 that connect the substrate main body 501 and the energy storage unit 50. The energy storage unit 50 includes a limiting portion 440 arranged on the outer periphery of the wiring substrate 500. The limiting portion 440 contacts a peripheral portion 505 of the wiring substrate 500, thereby limiting movement of the wiring substrate 500 in a direction intersecting the positive direction of the Z axis.

[0051] According to the energy storage device 1 of this embodiment, the limiting portions 440 are arranged on the outer periphery of the wiring substrate 500. This eliminates the need to provide, for example, through holes 509 or the like in the substrate main body 501 through which portions that limit the movement of the wiring substrate 500 pass. Therefore, for example, the wiring 530 can be arranged over a wide area of ​​the substrate main body 501 in a plan view. In other words, it is not necessary to secure an area in the substrate main body 501 for providing the through holes 509 or the like in addition to an area in which the multiple wirings 530 are arranged. This prevents the wiring substrate 500 from becoming too large.

[0052] Assume a case where a wall extending along the peripheral edge 505 of the wiring substrate 500 is positioned along the peripheral edge 505. In this case, due to dimensional tolerances of the wiring substrate 500 and / or the wall, interference between a portion of the peripheral edge 505 and the wall in the direction in which the peripheral edge 505 extends is likely to occur when the wiring substrate 500 is placed in the bus bar case 401. This may result in unintended deformation of a portion of the wiring substrate 500. To avoid this, if the wall is placed at a position away from the peripheral edge 505, the wall cannot substantially restrict movement of the wiring substrate 500. In this regard, the limiting portion 440 according to the present embodiment has a shape known as a "pin," "protrusion," or "columnar portion," for example. Therefore, even if the limiting portion 440 comes into contact with the peripheral edge 505 when the wiring substrate 500 is placed in the bus bar case 401, the contact length in the direction in which the peripheral edge 505 extends is relatively short. Simply put, the limiting portion 440 can be described as restricting the movement of the wiring substrate 500 at a "point." Therefore, even when designed to be positioned close to the peripheral portion 505, problematic deformation of the wiring substrate 500 is unlikely to occur. The limiting portion 440 according to the embodiment is a cylindrical portion as shown in FIG. 6 , and therefore contacts the peripheral portion 505 via a curved surface. Therefore, the length of the contact portion when the limiting portion 440 contacts the peripheral portion 505 is shorter than the length of the contact portion when the peripheral portion 505 contacts a flat surface. This more reliably suppresses the occurrence of problems with deformation of the wiring substrate 500 due to dimensional tolerances of the wiring substrate 500 and / or the limiting portion 440.

[0053] In this embodiment, the wiring substrate 500 further includes a connector 590 provided at an end of the substrate body 501 in the Y-axis direction, which intersects with the positive Z-axis direction (see FIGS. 4, 5B, and 6). The limiting portion 440 is disposed at a position closer to the connector 590 than the center of the substrate body 501 in the Y-axis direction. The center of the substrate body 501 in the Y-axis direction is a predetermined range including the center line CL (see FIG. 4). For example, the range includes the center line CL of the substrate body 501 and is a range of approximately 10% of the length of the substrate body 501 in the Y-axis direction.

[0054] The density of the wiring 530 is relatively high in a position on the substrate body 501 near the connector 590 (see FIG. 5B ). Therefore, it is difficult to arrange through holes or the like in the substrate body 501. In this regard, according to the energy storage device 1 according to the present embodiment, the limiting portion 440 is arranged at a position closer to the connector 590 than the center of the substrate body 501 and on the outer periphery of the wiring substrate 500. Therefore, in the region where the density of the wiring 530 is high, the limiting portion 440 can effectively limit the movement of the substrate body 501 without interfering with the arrangement of the wiring 530. In other words, there is no need to add an area for providing through holes or the like to the region of the wiring substrate 500 where the density of the wiring 530 is high.

[0055] In this embodiment, the power storage unit 50 includes a plurality of limiting portions 440. Of the plurality of limiting portions 440, the number of limiting portions 440 arranged closer to the connector 590 than to the center of the board body 501 in the Y-axis direction is greater than the number of limiting portions 440 arranged farther from the connector 590 than to the center of the board body 501 in the Y-axis direction. Specifically, in this embodiment, the power storage unit 50 includes seven limiting portions 440. The seven limiting portions 440 are distinguished as limiting portions 440a, 440b, 440c, 440d, 440e, 440f, and 440g, as shown in FIG. 4 , for example. Of these seven limiting portions 440, six limiting portions 440 (limiting portions 440a to 440f) are positioned closer to the connector 590 than the center of the substrate main body 501, and one limiting portion 440 (limiting portion 440g) is positioned farther from the connector 590 than the center of the substrate main body 501.

[0056] According to this configuration, a plurality of limiting portions 440 are arranged on the outer periphery of the wiring substrate 500. Furthermore, a greater number of limiting portions 440 among the plurality of limiting portions 440 are arranged in positions where the density of the wiring 530 is high, in a manner that does not interfere with the arrangement of the wiring 530. This makes it possible to more reliably and / or more accurately limit the movement of the substrate main body 501 while suppressing an increase in the size of the substrate.

[0057] In this embodiment, the peripheral portion 505 of the wiring substrate 500 includes a first peripheral portion 505a and a second peripheral portion 505b (see FIG. 5B and FIGS. 7A to 7C). The first peripheral portion 505a extends in the Y-axis direction, which intersects with the positive Z-axis direction. The second peripheral portion 505b extends in the X-axis direction, which intersects with the positive Z-axis direction and the Y-axis direction. The limiting portion 440 is disposed at a position along the first peripheral portion 505a and the second peripheral portion 505b.

[0058] 7A , the limiting portion 440a and the limiting portion 440b are disposed along the first peripheral portion 505a and the second peripheral portion 505b, which extend in directions intersecting each other. Therefore, the limiting portion 440a can limit the movement of the wiring substrate 500 in the negative Y-axis direction and the negative X-axis direction. The limiting portion 440b can limit the movement of the wiring substrate 500 in the negative Y-axis direction and the positive X-axis direction.

[0059] 7C , the limiting portion 440e is disposed at a position along two first and second peripheral portions 505a and 505b that face each other in the X-axis direction. More specifically, the limiting portion 440e is disposed at a position along the first peripheral portion 505a formed on the portion of the connecting piece 510 that extends in the Y-axis direction and the first peripheral portion 505a formed on the substrate main body 501, as well as the second peripheral portion 505b formed on the portion of the connecting piece 510 that extends in the X-axis direction. Therefore, the limiting portion 440e can limit movement of the wiring substrate 500 in the positive Y-axis direction, the positive X-axis direction, and the negative X-axis direction.

[0060] 7C , the limiting portion 440f is disposed at a position along the first peripheral portion 505a and the second peripheral portion 505b. More specifically, the limiting portion 440e is disposed at a position along the first peripheral portion 505a formed on the substrate main body 501 and the second peripheral portion 505b formed on the portion of the connecting piece 510 extending in the X-axis direction. Therefore, the limiting portion 440f can limit movement of the wiring substrate 500 in the negative Y-axis direction and the positive X-axis direction.

[0061] As described above, in the energy storage device 1 according to the present embodiment, the movement of the substrate body 501 in the X-axis direction is restricted by the contact of the limiting portion 440 with the first peripheral edge portion 505a, and the movement of the substrate body 501 in the Y-axis direction is restricted by the contact of the limiting portion 440 with the second peripheral edge portion 505b. This allows the movement of the substrate body 501 to be restricted more efficiently by one limiting portion 440. Furthermore, by increasing the number of limiting portions 440 arranged along the first peripheral edge portion 505a and the second peripheral edge portion 505b, the movement of the substrate body 501 can be restricted even more efficiently.

[0062] Of the seven limiting portions 440, limiting portions 440c and 440d are positioned along the first peripheral edge portion 505a, as shown in FIG. 7B . Specifically, the U-shaped substrate main body 501, which is elongated in the Y-axis direction in a plan view, is roughly divided into a first main body portion 501a in the positive X-axis direction and a second main body portion 501b in the negative X-axis direction. Limiting portion 440c is positioned along the first peripheral edge portion 505a of the second main body portion 501b in the positive X-axis direction. This limits movement of the wiring substrate 500 in the positive X-axis direction. Limiting portion 440d is positioned along the first peripheral edge portion 505a of the first main body portion 501a in the negative X-axis direction. This limits movement of the wiring substrate 500 in the negative X-axis direction.

[0063] In the present embodiment, the energy storage unit 50 includes a bus bar 300 connected to the energy storage element 100 and one of the plurality of connection pieces 510, and a bus bar case 401 that holds the bus bar 300 and is arranged in the positive direction of the Z axis of the energy storage element 100. The limiting portion 440 is arranged in the bus bar case 401.

[0064] According to this configuration, the bus bar case 401, which is disposed close to the wiring board 500 in the Z-axis direction, is used as a base member for the limiting portion 440. This allows the limiting portion 440 to more stably limit the movement of the wiring board 500. More specifically, in this embodiment, the limiting portion 440, which is a portion that protrudes in the Z-axis direction, is provided on a member (the bus bar case 401) that contacts the wiring board 500 in the Z-axis direction (see FIGS. 6 and 8 ). Therefore, the base portion of the limiting portion 440 (the end portion of the limiting portion 440 that is connected to the bus bar case 401), which is a portion that is less likely to deform or displace, comes into contact with the peripheral portion 505 of the wiring board 500. This allows the movement of the wiring board 500 to be more stably limited.

[0065] The above has mainly described the configuration of the limiting unit 440 and its periphery in the energy storage device 1 according to the embodiment. However, the configuration of the limiting unit 440 and its periphery may be different from the configuration shown in Figures 1 to 8. Therefore, below, modifications of the configuration of the limiting unit 440 and its periphery will be described, focusing on the differences from the above embodiment.

[0066] 10 is a cross-sectional view of a restricting portion 441 according to a first modification of the embodiment. The position of the cross section in Fig. 10 corresponds to the position of the cross section in Fig. 8.

[0067] The limiting portion 441 according to this modification is a portion that can be provided in the power storage device 1 instead of or in addition to the limiting portion 440 according to the embodiment. The limiting portion 441 contacts the peripheral portion 505 of the wiring substrate 500, thereby limiting movement of the wiring substrate 500 in a direction intersecting with the positive direction of the Z axis. This is common to the limiting portion 440 according to the embodiment.

[0068] The limiting portion 441 according to this modification includes a first limiting portion 441a that faces the peripheral portion 505 of the wiring substrate 500 in a direction intersecting the positive Z-axis direction (the X-axis direction in FIG. 10 ), and a second limiting portion 441b that faces the peripheral portion 505 of the wiring substrate 500 in the positive Z-axis direction. In this respect, the limiting portion 441 according to this modification differs from the limiting portion 440 according to the embodiment. In other words, the limiting portion 441 according to this modification includes the second limiting portion 441b, which is a claw portion that hooks onto the wiring substrate 500 in the Z-axis direction.

[0069] The restricting portion 441 according to this modification can restrict movement of the wiring substrate 500 in a direction intersecting the Z-axis direction and in the positive direction of the Z-axis. That is, the same effect as that of the convex portion 490 having the cross-sectional shape shown in Fig. 9 can be obtained. As a result, the energy storage device 1 according to this modification can more reliably restrict movement of the wiring substrate 500 while preventing the wiring substrate 500 from becoming larger.

[0070] In the energy storage device 1 according to this modification, when the convex portion 490 is prepared as a component separate from the bus bar case 401, the component may be used as the limiting portion 441. That is, the limiting portion 441 may have a shape including a shaft portion and a head portion (see FIG. 9 ).

[0071] 11 is a plan view showing a portion of a wiring board 500a according to a second modification of the embodiment. The wiring board 500a according to this modification is a member that can be provided in the energy storage device 1 in place of the wiring board 500 according to the embodiment. The wiring board 500a includes a board body 501 on which a plurality of wires 530 are arranged, and a plurality of connection pieces 510 that connect the board body 501 and the energy storage unit 50. This is common to the wiring board 500 according to the embodiment.

[0072] The wiring substrate 500a according to this modification differs from the wiring substrate 500 according to the embodiment in that a portion of the peripheral edge 505 includes a recess 508 that is recessed inward in a plan view. The recess 508 according to this modification accommodates a portion of the limiting portion 440 in a plan view. That is, in this modification, the limiting portion 440 is disposed along the inner periphery of the recess 508, which is part of the peripheral edge 505. This allows movement in multiple directions intersecting the positive direction of the Z axis to be restricted. For example, in FIG. 11 , the limiting portion 440 disposed along the inner periphery of the recess 508 can restrict movement of the wiring substrate 500a not only in the positive direction of the X axis, but also in the positive and negative directions of the Y axis. That is, the recess 508 can be hooked onto the limiting portion 440 in the Y axis direction. This allows the movement of the wiring substrate 500a to be restricted more efficiently by a single limiting portion 440.

[0073] In Figure 11, the recess 508 is provided in a part of the first peripheral portion 505a of the peripheral portion 505 extending in the Y-axis direction, but the recess 508 may also be provided in a part of the second peripheral portion 505b extending in the X-axis direction.

[0074] [4. Description of Other Modifications] The energy storage device 1 according to the embodiment of the present invention and its modifications have been described above, but the present invention is not limited to the above-described embodiment and modifications. The embodiment and modifications disclosed herein are illustrative in all respects, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0075] The number of limiting portions 440 included in the energy storage device 1 according to the embodiment is not limited to seven. The energy storage device 1 may include at least one limiting portion 440. By arranging at least one limiting portion 440 on the outer periphery of the wiring substrate 500, the movement of the wiring substrate 500 can be limited by the at least one limiting portion 440.

[0076] Of the multiple limiting units 440 included in the energy storage device 1 according to the embodiment, the number of limiting units 440 arranged closer to the connector 590 than the center of the substrate body 501 in the Y-axis direction may be equal to or less than the number of limiting units 440 arranged farther from the connector 590 than the center of the substrate body 501 in the Y-axis direction. Even in this case, movement of the wiring substrate 500 in the X-axis direction is restricted.

[0077] Although the limiting portion 440 included in the energy storage device 1 according to the embodiment is disposed along the first peripheral portion 505a and the second peripheral portion 505b, this configuration is not essential. For example, the limiting portion 440 may be disposed along only the second peripheral portion 505b. In other words, the limiting portion 440 does not have to be disposed along the first peripheral portion 505a. Even in this case, movement of the wiring substrate 500 in the X-axis direction is restricted.

[0078] Although the limiting portion 440 according to the embodiment has a cylindrical shape (see FIG. 6 ), there is no particular limitation on the shape of the limiting portion 440. The limiting portion 440 may have a polygonal prism shape, such as a square prism. The tip of the limiting portion 440 in the positive direction of the Z axis may have a curved or inclined surface so that the peripheral portion 505 does not get caught when the wiring substrate 500 is placed in the bus bar case 401.

[0079] The energy storage device 1 does not need to include a protrusion 490 that is disposed through a through-hole 509 provided in the wiring substrate 500. For example, one or more limiting portions 440 disposed along the peripheral portion 505 of the wiring substrate 500 may be provided in an area of ​​the substrate main body 501 far from the connector 590 (see FIG. 5A ). For example, consider a case where electrical components or wiring connected to the electrical components are disposed in an area of ​​the substrate main body 501 far from the connector 590, making it difficult to provide a through-hole 509 in that area. In this case, by arranging one or more limiting portions 440 along the peripheral portion 505 in that area, the movement of the entire wiring substrate 500 can be restricted in a balanced manner.

[0080] In the wiring substrate 500, the substrate body 501 and the connector 590 are connected by a connecting portion 502, but this configuration is not essential. For example, if the connector 590 is relatively small, it may be connected by solder or the like to the surface of the substrate body 501 in the positive direction of the Z axis. The arrangement of the connector 590 may be determined appropriately depending on the size, shape, etc. of the connector 590 provided on the wiring substrate 500.

[0081] The wiring board 500 does not need to include a connector 590 for detachably connecting to a cable extending from an external control device, etc. For example, a cable including a plurality of electric wires connected to a plurality of wirings 530 may be connected to the wiring board 500. In this case, the external control device, etc. may include a connector to which the cable can be connected.

[0082] There are no particular limitations on the shape and size of the connection piece 510 provided on the wiring substrate 500. The connection piece 510 may be formed, for example, by only a portion extending from the substrate main body 501 in the X-axis direction.

[0083] The wiring board 500 does not necessarily have to be a flexible printed circuit board having flexibility. The wiring board 500 may be a rigid board such as a glass epoxy board. In this case, the connecting piece 510 may be a flexible printed circuit board that is connected to the wiring board 500 by solder or the like.

[0084] The limiting portion 440 provided in the energy storage unit 50 may be provided in a member other than the bus bar case 401. For example, if the energy storage element array 10 includes a spacer adjacent to at least one energy storage element 100, one or more limiting portions 440 may be disposed at an end of the spacer in the positive direction of the Z axis. In this case, the multiple spacers may serve to hold the multiple bus bars 300. In other words, the energy storage unit 50 does not need to include the bus bar case 401.

[0085] The power storage device 1 does not need to include the case 600. For example, a structure including the power storage unit 50 and the wiring board 500 may be housed as the power storage device 1 in some kind of device, a rack, or the like.

[0086] The above supplementary notes regarding the energy storage device 1 according to the embodiment may be appropriately applied to the energy storage device 1 according to Modification 1 or 2. Configurations constructed by arbitrarily combining the components of the above embodiment and its modifications are also included within the scope of the present invention.

[0087] 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.

[0088] REFERENCE SIGNS LIST 1 Energy storage device 10 Energy storage element array 50 Energy storage unit 100 Energy storage element 400 Bus bar unit 401 Bus bar case 410 Bus bar accommodating portion 420 Board support portion 440, 440a, 440b, 440c, 440d, 440e, 440f, 440g, 441 Limiting portion 441a First limiting portion 441b Second limiting portion 490 Convex portion 491 Shaft portion 492 Head portion 500, 500a Wiring board 501 Board body 501a First body portion 501b Second body portion 502 Connecting portion 505 Peripheral edge portion 505a First peripheral edge portion 505b Second peripheral edge portion 508 Recessed portion 509 Through hole 510 Connection piece 530 Wiring 580 Conductive member 590 Connector

Claims

1. An energy storage device comprising: an energy storage unit having an energy storage element; and a wiring board arranged in a first direction of the energy storage unit, wherein the wiring board has a board body on which a plurality of wires are arranged, and a plurality of connection pieces connecting the board body and the energy storage unit, and the energy storage unit has a limiting portion arranged on the outer periphery of the wiring board, and the limiting portion contacts a peripheral portion of the wiring board to limit movement of the wiring board in a direction intersecting the first direction.

2. The energy storage device according to claim 1, wherein the wiring board further comprises a connector provided at an end of the board body in a second direction intersecting the first direction, and the limiting portion is positioned closer to the connector than the center of the board body in the second direction.

3. The energy storage device according to claim 2, wherein the energy storage unit includes a plurality of limiting portions, and the number of limiting portions that are arranged closer to the connector than the center of the substrate body in the second direction is greater than the number of limiting portions that are arranged farther from the connector than the center of the substrate body in the second direction.

4. The energy storage device according to any one of claims 1 to 3, wherein the peripheral portion of the wiring board includes a first peripheral portion and a second peripheral portion, the first peripheral portion extends in a second direction intersecting with the first direction, the second peripheral portion extends in a third direction intersecting with the first direction and the second direction, and the limiting portion is disposed at a position along the first peripheral portion and the second peripheral portion.

5. The energy storage device according to any one of claims 1 to 3, wherein the energy storage unit comprises: a bus bar connected to the energy storage element and one of the plurality of connection pieces; and a bus bar case that holds the bus bar and is arranged in the first direction of the energy storage element, and the limiting portion is arranged in the bus bar case.

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