Battery pack

Abstract

To provide a battery pack in which a bus bar can be precisely positioned in a bus bar module.SOLUTION: A plate member has a wall portion defining a space for installing each of a plurality of bus bars adjacent to each other in a stacking direction (first direction) of battery cells.The wall portion has a first portion and a second portion each extending in a second direction orthogonal to the first direction, and a third portion that connects the first portion and the second portion. The first portion and the second portion are located at positions separated from each other in the first direction. The third portion extends in the first direction.The wall portion further includes ribs that protrude from the wall portion to both sides in the first direction and that position, in the first direction, the plurality of bus bars adjacent to each other.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present technology relates to battery packs. [Background technology]

[0002] Chinese Patent Application Publication No. 115189104 (Patent Document 1) shows a battery connection module (busbar module) in which a plurality of busbars are housed in a carrier plate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Patent Application Publication No. 115189104 Summary of the Invention [Problem to be solved by the invention]

[0004] When connecting the electrode terminals of the battery cells to the bus bars, it is preferable that the battery cells and the bus bars are positioned with high precision relative to each other. Therefore, in a bus bar module, it is preferable that the bus bars housed in the plate members are positioned with high precision.

[0005] An object of the present technology is to provide a battery pack that allows accurate positioning of bus bars in a bus bar module. [Means for solving the problem]

[0006] The present technology provides the following battery pack.

[0007] [1] A battery pack comprising: a stack including a plurality of battery cells lined up in a first direction; a case for housing the stack; bus bars arranged on the stack and electrically connecting the plurality of battery cells; and a bus bar module including a plate member for housing the bus bars, wherein the plate member has a wall portion that defines a space for installing each of the plurality of bus bars adjacent to each other in the first direction, the wall portion having a first portion and a second portion that extend in a second direction perpendicular to the first direction, and a third portion that connects the first portion and the second portion, the first portion and the second portion being spaced apart from each other in the first direction, the third portion extending in the first direction, and the wall portion further including ribs that protrude from the wall portion on both sides in the first direction and position the adjacent plurality of bus bars in the first direction. [2] The battery pack according to [1], wherein the rib is located adjacent to the third portion.

[0008] [3] The battery pack according to [1] or [2], wherein the wall portion further includes a mechanism for locking the bus bar from a third direction perpendicular to the first direction and the second direction.

[0009] [4] A battery pack according to any one of [1] to [3], wherein the bus bar includes a root portion extending in a first direction, and first and second connection portions protruding from the root portion in a second direction and electrically connecting to the plurality of battery cells, and the ribs are positioned to abut on both sides of the root portion in the first direction, the first connection portion, and the second connection portion. [Effects of the Invention]

[0010] According to the present technology, a battery pack can be provided that allows accurate positioning of the busbar in the busbar module by providing the busbar module with a rib that positions the busbar in the stacking direction (first direction) of the battery cells. Here, by having the wall portion have a crank shape including the first portion to the third portion, it is possible to improve the positioning accuracy of the busbar while suppressing a decrease in workability when pushing the busbar in. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] FIG. 10 is a top view of a plate member in the bus bar module. [Figure 4] FIG. 2 is a perspective view showing the structure around the bus bar. [Figure 5] 10A and 10B are diagrams illustrating a positioning mechanism for the bus bar module in the Y-axis direction. [Figure 6] FIG. 2 is a perspective view showing the structure between the bus bar module and the upper surface of the battery cell. [Figure 7] FIG. 2 is a perspective view showing a rear surface of a plate member in the bus bar module. [Figure 8] 10A and 10B are diagrams illustrating a positioning mechanism for the bus bar module in the X-axis direction. [Figure 9] FIG. 5 is a diagram showing the structure shown in FIG. 4 as viewed from above. [Figure 10] 10 is a cross-sectional view taken along the line XX in FIG. 9. [Figure 11] 10 is a cross-sectional view taken along the line XI-XI in FIG. 9. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof may not be repeated.

[0013] In the embodiments described below, when numbers, amounts, etc. are mentioned, the scope of the present technology is not necessarily limited to those numbers, amounts, etc., unless otherwise specified. Furthermore, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. Furthermore, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiments.

[0014] In this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a certain feature is included, other features may or may not be included.

[0015] Furthermore, when geometric terms and terms expressing positional and directional relationships are used in this specification, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along," these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in a single state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0016] In this specification, "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, "battery packs" can be installed in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). However, the use of "battery cells" is not limited to in-vehicle use.

[0017] Fig. 1 is an exploded perspective view of a battery pack 1. As shown in Fig. 1, the battery pack 1 includes a stack 10 including a plurality of battery cells 100 (see Fig. 2) arranged in the Y-axis direction (first direction), a case 20 that houses the stack 10, and a bus bar module 30 arranged on the stack 10.

[0018] The laminate 10 includes a laminate 10A (first laminate), a laminate 10B (second laminate), and a laminate 10C (third laminate). The laminates 10A and 10B are adjacent to each other in the X-axis direction (second direction). The laminates 10B and 10C are adjacent to each other in the X-axis direction.

[0019] The case 20 has side walls 21 that face the stacks 10A, 10B, and 10C in the Y-axis direction. The side walls 21 directly support the stacks 10A, 10B, and 10C from both sides in the Y-axis direction. In this way, the battery pack 1 according to this embodiment employs a cell-to-pack structure in which the stack 10, which includes multiple battery cells 100, is housed directly in the case.

[0020] The busbar module 30 includes a busbar module 30A (first busbar module) arranged on the laminate 10A, a busbar module 30B (second busbar module) arranged on the laminate 10B, and a busbar module 30C (third busbar module) arranged on the laminate 10C.

[0021] Fig. 2 is a perspective view showing the configuration of the battery cell 100 that makes up the laminates 10A, 10B, and 10C. As shown in Fig. 2, the battery cell 100 has a rectangular shape. The battery cell 100 has an electrode terminal 110, a housing 120, and a gas release valve 130.

[0022] The electrode terminals 110 are formed on the housing 120. The electrode terminals 110 include a positive terminal 111 and a negative terminal 112 as two electrode terminals 110 aligned along an X-axis direction (second direction) perpendicular to a Y-axis direction (first direction). The positive terminal 111 and the negative terminal 112 are spaced apart from each other in the X-axis direction.

[0023] The housing 120 has a substantially rectangular parallelepiped shape. An electrode assembly and an electrolyte (not shown) are housed in the housing 120. The housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and a third side surface 125.

[0024] The upper surface 121 is a plane perpendicular to the Z-axis direction. The electrode terminals 110 are disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction (third direction) perpendicular to the Y-axis direction (first direction) and the X-axis direction (second direction).

[0025] Each of the first side surface 123 and the second side surface 124 is made of a plane perpendicular to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the multiple side surfaces of the housing 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction, with the X-axis direction being the longitudinal direction and the Z-axis direction being the lateral direction.

[0026] The multiple battery cells 100 are stacked such that the first side surfaces 123 and the second side surfaces 124 of the battery cells 100 adjacent to each other in the Y-axis direction face each other. As a result, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately in the Y-axis direction in which the multiple battery cells 100 are stacked.

[0027] Gas exhaust valve 130 is provided on top surface 121. When the internal pressure of housing 120 rises to a predetermined value or higher due to gas generated inside housing 120, gas exhaust valve 130 opens and exhausts the gas to the outside of housing 120.

[0028] Next, the basic configuration of the busbar module 30 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a top view of a plate member 310 included in the busbar module 30. Fig. 4 is a perspective view showing the structure around a busbar 320 in the busbar module 30.

[0029] Each of the busbar modules 30A, 30B, and 30C includes a plate member 310 shown in Fig. 3. As shown in Fig. 3, the plate member 310 includes an end face 311 located at the end in the Y-axis direction, an end face 312 located at the end in the X-axis direction, through-holes 313 formed at positions corresponding to the gas release valves 130 of the battery cells 100, and wall portions 314 that divide the space on the plate member 310 into multiple sections.

[0030] As shown in FIG. 4, a bus bar 320 is housed in each space separated by the wall portion 314. The bus bar 320 is made of a conductor (typically, a metal member). The bus bar 320 electrically connects the electrode terminals 110 of the multiple battery cells 100 to one another. The bus bar 320 includes a root portion 321 extending in the Y-axis direction, and a connection portion 322 (first connection portion) and a connection portion 323 (second connection portion) protruding from the root portion 321 in the X-axis direction. The connection portions 322 and 323 are each connected to the electrode terminals 110 of two battery cells 100 adjacent to each other in the Y-axis direction.

[0031] The wall portion 314 of the plate member 310 includes a first portion 314A, a second portion 314B, and a third portion 314C. The first portion 314A and the second portion 314B are formed to extend in the X-axis direction. The first portion 314A and the second portion 314B are spaced apart from each other in the Y-axis direction. The third portion 314C connects the first portion 314A and the second portion 314B.

[0032] Ribs 315 and locks 316 are formed on wall portion 314. Ribs 315 protrude on both sides in the Y-axis direction from positions adjacent to third portion 314C of wall portion 314. Ribs 315 position adjacent bus bars 320 in the Y-axis direction. Locks 316 lock bus bars 320 in the Z-axis direction. The shapes and arrangements of ribs 315 and locks 316 are not limited to those shown in FIG. 4 and can be changed as appropriate.

[0033] Bus bar 320 is connected to wiring 410. Wiring 410 is fixed to bus bar 320 by screws 420. The configuration of wiring 410 and screws 420 is not limited to that shown in Fig. 4, and the wiring may be formed by, for example, a flexible wiring board.

[0034] The electrode terminals 110 and bus bars 320 of the battery cells 100 are welded together after being positioned relative to each other in the X-axis and Y-axis directions. By performing this positioning accurately, the welding process between the electrode terminals 110 and the bus bars 320 can be performed with high efficiency and quality. Therefore, when storing the bus bars 320 in the space partitioned by the wall portions 314, it is preferable to accurately position the bus bars 320 relative to the plate members 310. It is also preferable to accurately position the plate members 310 and the stack 10.

[0035] The positioning mechanism of the bus bar module 30 (plate member 310) in this embodiment will be described with reference to FIGS.

[0036] Fig. 5 is a diagram showing a positioning mechanism for the busbar module 30 in the Y-axis direction. As shown in Fig. 5, the plate member 310 of the busbar module 30 has a positioning mechanism 317 that urges the side wall 21 of the case 20 to position the busbar module 30 in the Y-axis direction.

[0037] 5 is configured with a snap-fit ​​protrusion formed on the end surface 311 of the plate member 310. The protrusion that constitutes the positioning mechanism 317 protrudes from the end surface 311 of the plate member 310 toward the side wall 21. When the plate member 310 is installed in the case 20, the positioning mechanism 317 presses against the side wall 21 of the case 20, urging the plate member 310 toward a predetermined position. As a result, the busbar module 30 is positioned in the Y-axis direction.

[0038] The positioning mechanisms 317 may be provided on end faces 311 on both sides of the plate member 310 in the Y axis direction, or on only one side of the plate member 310 in the Y axis direction. When the positioning mechanisms 317 are provided on both sides in the Y axis direction, the plate member 310 is urged toward the center of the case 20 in the Y axis direction, and is positioned at a position where the urging forces by the positioning mechanisms 317 on both sides are balanced. When the positioning mechanism 317 is provided on one side in the Y axis direction, the plate member 310 is urged toward the side wall 21 opposite to the side on which the positioning mechanism 317 is provided, and is positioned using the side wall 21 as a reference plane.

[0039] The protrusions that make up the positioning mechanism 317 deform toward the center of the stack 10 as a reaction to the pressure on the side wall 21 of the case 20. At this time, it is preferable that the positioning mechanism 317 is located in a position that does not interfere with the gas release valve 130 when viewed from the Z axis direction. This makes it possible to position the busbar module 30 in the Y axis direction without affecting the release of gas from the gas release valve 130 of the battery cell 100 located at the end in the Y axis direction.

[0040] FIG. 6 is a perspective view showing the structure between the bus bar module 30 and the upper surface 121 of the battery cell 100.

[0041] As shown in FIG. 6, the stack 10 includes separators 11 disposed between the multiple battery cells 100. The separators 11 may be a film or tape that covers the first side surface 123, the second side surface 124, and the third side surface 125 of the battery cells 100. The separators 11 may also be a film that encases the housing 120. The separators 11 may also be plate-shaped members (plates) that are sandwiched between adjacent battery cells 100. The separators 11 may also be formed by combining the above film or tape with a plate-shaped member. The separators 11 have protruding portions 11A that protrude toward the plate member 310 beyond the multiple battery cells 100. The plate member 310 has recessed portions 318 that avoid the protruding portions 11A of the separators 11.

[0042] FIG. 7 is a perspective view showing the back surface of the plate member 310. As shown in FIG. 7, the plate member 310 has a bottom surface 319A. The bottom surface 319A faces the top surface of the battery cell 100. A protruding rib 319 that protrudes from the bottom surface 319A of the plate member 310 toward the top surface 121 of the battery cell 100 is provided on part of the bottom surface 319A of the plate member 310. The protruding rib 319 abuts against the top surface 121 of the battery cell 100. In the example of FIG. 7, the protruding rib 319 is formed discontinuously on both sides of the through-hole 313 so as to extend in the Y-axis direction.

[0043] Fig. 8 is a diagram showing a positioning mechanism for the busbar module 30 in the X-axis direction. As shown in Fig. 8, the busbar module 30 has a positioning mechanism 330 that is inserted between two adjacent laminates (laminates 10A and 10B in the example of Fig. 8) and positions the busbar module 30 in the X-axis direction. In the example of Fig. 8, the laminate 10A has the positioning mechanism 330A, and the laminate 10B has the positioning mechanism 330B, but the scope of the present technology is not limited to a case where all laminates 10 have the positioning mechanism 330, and only some of the multiple laminates 10 may have the positioning mechanism 330.

[0044] The positioning mechanism 330A has an insertion portion 331A that is press-fitted between the laminates 10A and 10B. When the insertion portion 331A is press-fitted between the laminates 10A and 10B, the busbar module 30A is urged in a direction away from the laminate 10B. At this time, the insertion portion 331A comes into contact with a side surface of the laminate 10A, thereby positioning the busbar module 30A in the X-axis direction.

[0045] The positioning mechanism 330B has an insertion portion 331B that is press-fitted between the laminates 10A and 10B. When the insertion portion 331B is press-fitted between the laminates 10A and 10B, the busbar module 30B is urged in a direction away from the laminate 10A. At this time, the insertion portion 331B comes into contact with a side surface of the laminate 10B, thereby positioning the busbar module 30B in the X-axis direction.

[0046] Next, the positioning of bus bar 320 relative to plate member 310 will be described in more detail with reference to Figures 9 to 11. Figure 9 is a diagram showing the structure shown in Figure 4 as viewed from above, and Figures 10 and 11 are cross-sectional views taken along lines XX and XI-XI in Figure 9.

[0047] In the example shown in FIG. 9, in a substantially rectangular space partitioned by wall portion 314, ribs 315 are provided at four locations and locks 316 are provided at three locations.

[0048] More specifically, ribs 315 are provided on both sides (two locations) of base portion 321 of bus bar 320 and at positions (one location each) that abut against connecting portions 322 and 323. Locks 316 are provided on one side (one location) of base portion 321 of bus bar 320 and at positions (one location each) that abut against connecting portions 322 and 323.

[0049] However, if a flexible substrate is provided instead of the wiring 410 shown in FIG. 9, the screw 420 can be omitted, and therefore it is also possible to add a lock 316 near the screw 420, thereby providing four locks 316 for one bus bar 320.

[0050] The first portion 314A, the second portion 314B, and the third portion 314C of the wall portion 314 form a crank shape. The rib 315 is formed to protrude toward both sides in the Y-axis direction from a position adjacent to the third portion 314C that forms the crank shape. The lock 316 is formed at a position spaced apart from the third portion 314C and the rib 315 in the X-axis direction.

[0051] 10, rib 315 positions bus bar 320 in the Y-axis direction by abutting against bus bar 320 from the side (Y-axis direction). When bus bar 320 is accommodated in plate member 310, bus bar 320 is moved downward while being aligned with inclined surface 315A provided above rib 315. From the viewpoint of improving the positioning accuracy of bus bar 320, it is preferable that the gap (tolerance) between rib 315 and bus bar 320 be as small as possible.

[0052] 11 , lock 316 abuts against bus bar 320 from above (in the Z-axis direction) to lock bus bar 320 in the Z-axis direction. When bus bar 320 is to be accommodated in plate member 310, bus bar 320 is moved downward while aligning with inclined surface 316A provided above lock 316. At this time, wall portion 314 is deformed so as to bend, allowing bus bar 320 to be pushed downward beyond the protruding portion of lock 316.

[0053] If a single wall is provided at a position corresponding to the midpoint between the first portion 314A and the second portion 314B of the wall 314, and the rib 315 and the lock 316 protrude from that position, the amount by which the rib 315 and the lock 316 protrude from the wall 314 must be increased, which means that the inclined surfaces 315A, 316A must be extended or their inclination relative to the vertical must be increased (the inclination of the inclined surfaces 315A, 316A must be made closer to the horizontal) compared to the structures shown in Figures 9 to 11. As a result, it becomes more difficult to smoothly push the bus bar 320 downward toward the battery cell 100.

[0054] On the other hand, if a pair of walls is provided at positions corresponding to first portion 314A and second portion 314B of wall portion 314, respectively, and rib 315 and lock 316 are protruded from the respective positions, it is possible to provide rib 315 and lock 316 with the same shapes as those shown in FIGS. 9 to 11. However, a narrow gap must be provided between the pair of walls, which makes it difficult to form plate member 310 by resin molding. Even if resin molding is possible, since the pair of walls are formed close to each other in the Y-axis direction, when one wall bends near lock 316 during the process of pushing bus bar 320, it may interfere with the other wall.

[0055] Furthermore, if the pair of wall portions are integrated, a thick wall portion 314 is formed, which may impair the flexibility of wall portion 314 (near lock 316) required when pushing bus bar 320. Furthermore, this may hinder efforts to reduce the weight and manufacturing costs of plate member 310.

[0056] In busbar module 30 according to this embodiment, wall portion 314 of plate member 310 has a crank shape, and ribs 315 protrude from first portion 314A and second portion 314B, which are positioned closer to busbar 320 in the Y-axis direction, toward busbar 320. This reduces the gap between rib 315 and busbar 320 in the Y-axis direction while reducing the protruding height of rib 315, thereby improving the positioning accuracy of busbar 320, without making wall portion 314 excessively thick.

[0057] The battery pack 1 employs a cell-to-pack structure in which a stack 10 containing multiple battery cells 100 is stored directly in a case 20, and therefore components such as bind bars in the module structure cannot be used as positioning components for the bus bar module 30.

[0058] In the battery pack 1 according to this embodiment, the positioning mechanism 317 provided on the plate member 310 biases the side wall 21 of the case 20, thereby positioning the busbar module 30 in the Y-axis direction. Therefore, in the battery pack 1 having a cell-to-pack structure, the busbar module 30 can be positioned with high accuracy without providing a complex mechanism.

[0059] In the battery pack 1, protruding ribs 319 that protrude from the bottom surface 319A of the plate member 310 toward the battery cell 100 abut against the top surface 121 of the battery cell 100. By abutting the protruding ribs 319 against the battery cell 100 in this way, the contact area between the plate member 310 and the top surface 121 of the battery cell 100 is reduced, reducing frictional resistance when the plate member 310 moves relative to the battery cell 100, and enabling smooth and accurate positioning of the plate member 310.

[0060] The shape or arrangement of the protruding ribs 319 is not limited to that shown in Fig. 7. Furthermore, the protruding ribs 319 are not necessarily an essential component in the present technology.

[0061] In the battery pack 1, the plate member 310 has the recess 318 that avoids the protrusion 11A of the separator 11, so when the positioning mechanism 317 positions the plate member 310 in the Y-axis direction, the movement of the plate member 310 in the Y-axis direction is not hindered by the protrusion 11A of the separator 11. This allows the plate member 310 to be positioned smoothly and accurately.

[0062] However, in the present technology, the protrusion 11A of the separator 11 and the recess 318 of the plate member 310 are not necessarily essential components.

[0063] The battery pack 1 is provided with a positioning mechanism 330 that is inserted between the laminates 10A and 10B and positions the busbar modules 30A and 30B in the X-axis direction. This allows the plate member 310 to be positioned in the X-axis direction as well as the Y-axis direction.

[0064] However, in the present technology, the X-axis direction positioning mechanism 330 is not necessarily a required configuration. Also, all of the plurality of stacks 10A, 10B, and 10C may be provided with the positioning mechanism 330, or only some of the plurality of stacks 10A, 10B, and 10C may be provided with the positioning mechanism 330.

[0065] Although the embodiments of the present technology have been described above, the embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0066] REFERENCE SIGNS LIST 1 battery pack, 10, 10A, 10B, 10C laminate, 11 separator, 11A protrusion, 20 case, 21 side wall, 30, 30A, 30B, 30C busbar module, 100 battery cell, 110 electrode terminal, 110A protrusion, 111 positive terminal, 112 negative terminal, 120 housing, 121 upper surface, 122 lower surface, 123 first side, 124 second side, 125 third side, 130 gas release valve, 310 plate member, 311, 312 end surface, 313 through hole, 314 wall portion, 314A first portion, 314B second portion, 314C third portion, 315 rib, 315A inclined surface, 316 lock, 316A inclined surface, 317 Positioning mechanism, 318 recess, 319 protruding rib, 319A bottom surface, 320 bus bar, 321 root portion, 322, 323 connection portion, 330, 330A, 330B positioning mechanism, 331A, 331B insertion portion, 410 wiring, 420 screw.

Claims

1. a stack including a plurality of battery cells arranged in a first direction; a case for housing the laminate; a bus bar module that is disposed on the stack and that includes bus bars that electrically connect the plurality of battery cells and plate members that house the bus bars; the plate member has a wall portion that partitions spaces for installing the plurality of bus bars that are adjacent to each other in the first direction, the wall portion has a first portion and a second portion extending in a second direction perpendicular to the first direction, and a third portion connecting the first portion and the second portion, the first portion and the second portion being spaced apart from each other in the first direction, and the third portion extending in the first direction; the first portion, the second portion, and the third portion of the wall form a crank shape; the wall portion further includes ribs protruding from the wall portion on both sides in the first direction and positioning adjacent ones of the bus bars in the first direction.

2. The battery pack according to claim 1 , wherein the rib is located adjacent to the third portion.

3. 3. The battery pack according to claim 1, wherein the wall portion further includes a mechanism for locking the bus bar from a third direction perpendicular to the first direction and the second direction.

4. the bus bar includes a root portion extending in the first direction, and first and second connection portions protruding from the root portion in the second direction and electrically connected to the plurality of battery cells, respectively; 3. The battery pack according to claim 1, wherein the ribs are positioned to abut on both sides of the base portion in the first direction, the first connection portion, and the second connection portion.

Images