Bus bar and battery pack

Abstract

This bus bar 320 has a first member 321 and a second member 322 laminated with the first member 321. The first member 321 and the second member 322 include a solid-phase junction 320A formed by solid-phase bonding with each other. The first member 321 includes a concave recess 321e exposed to a first outer edge 321d (outer edge). The second member 322 includes a concave recess 322e exposed to a first outer edge 322d (outer edge). The recess 321e and the recess 322e are adjacent to the solid-phase junction 320A.

Description

Busbar and battery pack

[0001] The present invention relates to a bus bar and a battery pack.

[0002] BACKGROUND ART Bus bars formed by solid-state joining of two or more members have been known (see, for example, Patent Document 1).

[0003] JP 2011-210480 A

[0004] There is a demand for a bus bar in which the upper limit values ​​of the outer dimensions of the two or more members satisfy a predetermined range when the two or more members are solid-state welded together, and for a battery pack having the bus bar.

[0005] The bus bar includes a first member and a second member laminated on the first member. The first member and the second member include a solid-state welded portion formed by solid-state welding. At least one of the first member and the second member includes a concave recess exposed at an outer edge. The recess is adjacent to the solid-state welded portion.

[0006] The battery pack includes a battery and the bus bar connected to the battery.

[0007] In a state where two or more members are solid-state welded together, it is possible to obtain a bus bar in which the upper limit values ​​of the outer dimensions of the two or more members satisfy a predetermined range, and a battery pack having the bus bar.

[0008] 9 is a perspective view showing a battery pack 1 of a first embodiment. It is a top view of the battery pack 1 of FIG. 1. It is a perspective view showing a plurality of batteries 100 and a holding unit 200, with some of the components of the holding unit 200 exploded in the width direction Y and the stacking direction X. It is a perspective view showing the components of the batteries 100 and the holding unit 200 exploded in the stacking direction X, with the first side plate 231, the second side plate 232, and the fastening bolts 241 removed from FIG. 3. It is a perspective view showing the busbar unit 300, the voltage detection unit 400, the temperature measurement unit 500, and the busbar holder 340, excluding the busbar holder 340, separated in the height direction Z. It is a perspective view showing an enlarged region 6 of FIG. 1. It is a perspective view showing the busbar 320 from above. It is a perspective view showing the busbar 320 of FIG. 7 from below. It is a top view showing the busbar 320 of FIG. 7. It is a top view showing an enlarged region 10 of FIG. 9. 11 , a bottom view showing a bus bar 320 of FIG. 7 , a bottom view showing an enlarged region 12 of FIG. 11 , a side view showing the bus bar 320 of FIG. 7 , an exploded perspective view showing a first member 321 and a second member 322 of the bus bar 320 of FIG. 7 , a top view showing a main portion of a bus bar 610 of a second embodiment, a bottom view showing the bus bar 610 of FIG. 15 , a top view showing a main portion of a bus bar 620 of a third embodiment, a bottom view showing the bus bar 620 of FIG. 17 , a perspective view showing a main portion of a bus bar 630 of a fourth embodiment, a perspective view showing a main portion of a bus bar 640 of a fifth embodiment, a perspective view showing a main portion of a bus bar 650 of a sixth embodiment, a top view showing a main portion of a bus bar 660 of a seventh embodiment, a top view showing a main portion of a bus bar 670 of an eighth embodiment, and a top view showing a main portion of a bus bar 680 of a ninth embodiment. 27. A top view showing a main portion of a bus bar 710 of a tenth embodiment. A bottom view showing the bus bar 710 of FIG. 25. A top view showing a main portion of a bus bar 720 of an eleventh embodiment. A bottom view showing a main portion of the bus bar 720 of FIG. 27. A perspective view showing a bus bar 730 of a twelfth embodiment from above. A perspective view showing the bus bar 730 of FIG. 29 from below. A perspective view showing a bus bar 740 of a thirteenth embodiment from above. A perspective view showing the bus bar 740 of FIG. 31 from below. A perspective view showing a bus bar 750 of a fourteenth embodiment from above. A perspective view showing the bus bar 750 of FIG. 33 from below. A perspective view showing a bus bar 760 of a fifteenth embodiment from above. A perspective view showing the bus bar 760 of FIG. 35 from below. A perspective view showing a bus bar 770 of a sixteenth embodiment from above. FIG. 10 is a perspective view showing a main part of a bus bar 810 according to another embodiment.

[0009] Embodiments of the present invention will be described with reference to the drawings. To facilitate understanding of each embodiment, the size and proportions of components may be exaggerated in each drawing. The same reference numerals are used for the same components in each drawing. In each drawing, the stacking direction X, width direction Y, and height direction Z of the battery pack 1 are indicated by arrows. However, in each drawing, the stacking direction X, width direction Y, and height direction Z of the battery pack 1 indicate the relative positional relationship within the same drawing. That is, if the battery pack 1 is rotated 180 degrees and placed with the top and bottom sides reversed, or if the battery pack 1 is rotated 90 degrees and placed with the top side facing sideways, the stacking direction X, width direction Y, and height direction Z of the battery pack 1 will change. In each drawing, the threads on the outer surfaces of the fastening bolts and the grooves on the inner surfaces of the insert nuts are omitted.

[0010] The direction in which the first member 321 and the second member 322 of the bus bar 320 are stacked is referred to as the "stacking direction A" of the first member 321 and the second member 322. The stacking direction A corresponds to the height direction Z of the battery pack 1. The direction in which the horn is vibrated during ultrasonic bonding of the first member 321 and the second member 322 is referred to as the "vibration direction B." The vibration direction B is perpendicular to the stacking direction A. The vibration direction B corresponds to the stacking direction X of the battery pack 1. The directions perpendicular to both the stacking direction A and the vibration direction B are referred to as the "width direction C" of the first member 321 and the second member 322. The width direction C corresponds to the width direction Y of the battery pack 1.

[0011] In each embodiment and each modified example of each embodiment, the same components as those described above are denoted by the same reference numerals, and redundant explanations are omitted. The same components as those described above include not only the same components as those described above, but also components that are substantially the same as those described above.

[0012] (Configuration of Battery Pack 1 Including Bus Bar 320 and Other Components of First Embodiment) The configuration of the battery pack 1 including the bus bar 320 and other components of the first embodiment will be described with reference to FIGS. 1 to 14 .

[0013] FIG. 1 is a perspective view showing a battery pack 1 of a first embodiment. FIG. 2 is a top view showing the battery pack 1 of FIG. 1. FIG. 3 is a perspective view showing a plurality of batteries 100 and a holding unit 200, with some of the components of the holding unit 200 disassembled in the width direction Y and the stacking direction X. FIG. 4 is a perspective view showing the components of the batteries 100 and the holding unit 200 disassembled in the stacking direction X, with the first side plate 231, the second side plate 232, and the fastening bolts 241 removed from FIG. 3. FIG. 5 is a perspective view showing the busbar unit 300, the voltage detection unit 400, the temperature measurement unit 500, and the busbar holder 340, excluding the busbar holder 340, separated in the height direction Z. FIG. 6 is an enlarged perspective view of region 6 in FIG. 1.

[0014] FIG. 7 is a perspective view showing the bus bar 320 from above. FIG. 8 is a perspective view showing the bus bar 320 of FIG. 7 from below. FIG. 9 is a top view showing the bus bar 320 of FIG. 7. FIG. 10 is a top view showing an enlarged view of a region 10 of FIG. 9. FIG. 11 is a bottom view showing the bus bar 320 of FIG. 7. FIG. 12 is a bottom view showing an enlarged view of a region 12 of FIG. 11. FIG. 13 is a side view showing the bus bar 320 of FIG. 7. FIG. 14 is a perspective view showing an exploded view of the first member 321 and the second member 322 of the bus bar 320 of FIG. 7.

[0015] The battery pack 1 is configured as, for example, a power source for operating a motor for running a vehicle. The battery pack 1 may also be configured as, for example, a power source for operating electrical equipment mounted on the vehicle.

[0016] 1, the battery pack 1 includes a plurality of batteries 100, a holding unit 200 that holds the plurality of batteries 100, and a busbar unit 300 that electrically connects the plurality of batteries 100. The battery pack 1 also includes a voltage detection unit 400 that detects the voltage of the batteries 100, and a temperature measurement unit 500 that measures the temperature of the batteries 100. The components included in the battery pack 1 will be described below.

[0017] (Configuration of Battery 100) The batteries 100 shown in Figs. 1 to 4 are stacked in a stacking direction X via holding units 200. As shown in Fig. 2, for example, 20 batteries 100 are stacked. The batteries 100 are configured, for example, by lithium ion secondary batteries. The batteries 100 include a current collector and an electrolyte. As shown in Fig. 4, the battery 100 includes a container 101, a lid 102, a positive electrode terminal 103, a negative electrode terminal 104, and a safety valve 105. The components included in the battery 100 will be described below.

[0018] As shown in FIG. 4 , the battery 100 is formed in a rectangular parallelepiped shape. A positive electrode terminal 103 and a negative electrode terminal 104 are provided on an upper surface 100a of the battery 100 along the stacking direction X. The upper surface 100a corresponds to the upper surface of the battery 100 in FIG. 4 . The upper surface 100a is formed in a rectangular shape. The length of the upper surface 100a along the width direction Y of the battery 100 is longer than the length of the upper surface 100a along the stacking direction X of the battery 100. The upper surface 100a faces the busbar unit 300 shown in FIG. 1 . Two side surfaces 100b along the stacking direction X of the battery 100 face each other perpendicularly to the upper surface 100a. The side surfaces 100b are formed in a rectangular shape. The length of the side surfaces 100b along the height direction Z of the battery 100 is longer than the length of the side surfaces 100b along the stacking direction X of the battery 100. Two main surfaces 100 c of the battery 100 that face each other in the stacking direction X are in contact with the cell spacers 202 and the like of the holding unit 200 .

[0019] The current collector of the battery 100 corresponds to a charge / discharge element between which electric power is input and output. The current collector of the battery 100 is configured by winding or stacking a positive electrode and a negative electrode with a separator interposed therebetween. The container 101 contains the current collector and an electrolyte. The lid 102, together with the container 101, seals the current collector and the electrolyte. The lid 102 is joined to the container 101. The positive electrode terminal 103 and the negative electrode terminal 104 relay the input and output of electric power between the current collector and the electrical device. The positive electrode terminal 103 and the negative electrode terminal 104 are attached to the lid 102. The positive electrode terminal 103 of one battery 100 and the negative electrode terminal 104 of the other battery 100, which are adjacent along the stacking direction X, face each other in the stacking direction X, as shown in FIG. 4 . The safety valve 105 ruptures toward the outside of the battery 100 when the internal pressure of the battery 100 exceeds a predetermined value. The safety valve 105 is also called a split valve. The safety valve 105 is provided in the lid 102, for example.

[0020] (Configuration of holding unit 200) The holding unit 200 shown in Figures 1 to 4 holds multiple batteries 100. As shown in Figure 4, the holding unit 200 includes a first end spacer 201, a cell spacer 202, and a second end spacer 203. The holding unit 200 also includes a first end block 211, a second end block 212, an insulating member 221, and an insert nut 222. As shown in Figure 3, the holding unit 200 also includes a first side plate 231, a second side plate 232, and a fastening bolt 241. The components included in the holding unit 200 will be described below.

[0021] As shown in FIG. 4 , the first end spacer 201 is provided between the first end block 211 and the battery 100. The first end spacer 201 contacts the first battery 100 located at one end of the 20 stacked batteries 100. This battery 100 corresponds to the battery 100 located at the left end in FIG. 2 . The first end spacer 201 insulates the first end block 211 from the battery 100. The first end spacer 201 covers each side surface of the first end block 211 and the battery 100 along the width direction Y. The first end spacer 201 covers a portion of the side surface 100b of the battery 100 along the stacking direction X. The thickness of the first end spacer 201 along the stacking direction X is sufficiently thinner than the thickness of the batteries 100 along the stacking direction X. The first end spacer 201 is formed of an insulating material.

[0022] As shown in FIG. 4 , the cell spacers 202 are provided between adjacent batteries 100. The cell spacers 202 hold and insulate the adjacent batteries 100. The cell spacers 202 cover the main surfaces 100c of the adjacent batteries 100 along the width direction Y and a portion of the side surfaces 100b of the adjacent batteries 100 along the stacking direction X. The thickness of the cell spacers 202 along the stacking direction X is sufficiently thinner than the thickness of the batteries 100 along the stacking direction X. The cell spacers 202 are made of an insulating material.

[0023] As shown in FIG. 4 , the second end spacer 203 is provided between the battery 100 and the second end block 212. The second end spacer 203 contacts the twentieth battery 100 located at the other end of the 20 stacked batteries 100. This battery 100 corresponds to the battery 100 located at the right end in FIG. 2 . The second end spacer 203 insulates the battery 100 from the second end block 212. The second end spacer 203 covers each side surface of the first end block 211 and the battery 100 along the width direction Y. The second end spacer 203 covers a portion of the side surface 100b of the battery 100 along the stacking direction X. The thickness of the second end spacer 203 along the stacking direction X is sufficiently thinner than the thickness of the batteries 100 along the stacking direction X. The second end spacer 203 is formed of an insulating material.

[0024] As shown in FIG. 4 , the first end block 211 is stacked with the first battery 100 located at one end of the 20 stacked batteries 100 via a first end spacer 201. The first end block 211 extends along a width direction Y that intersects with the stacking direction X of the batteries 100. The first end block 211 is adjacent to the battery 100 located at the end along the stacking direction X and supports the battery 100. The first end block 211 is formed in a rectangular parallelepiped shape extending in the width direction Y. Fastening bolts 241 are screwed into a plurality of screw holes 211m formed on the side surface of the first end block 211 along the width direction Y shown in FIG. 3 . The first end block 211 is fixed to the first side plate 231 by the fastening bolts 241, as shown in FIG. 1 . Similarly, the first end block 211 is fixed to the second side plate 232 by the fastening bolts 241. The first end block 211 is formed with insertion holes 211n for inserting bolts or the like for fixing the battery pack 1. The first end block 211 is made of, for example, metal or resin.

[0025] As shown in FIG. 4 , the second end block 212 is stacked with the twentieth battery 100 located at the other end of the 20 stacked batteries 100 via a second end spacer 203. The second end block 212 extends along the width direction Y of the batteries 100. The second end block 212 is adjacent to the battery 100 located at the end along the stacking direction X and supports the battery 100. The second end block 212 is formed in a rectangular parallelepiped shape extending in the width direction Y. Fastening bolts 241 are screwed into multiple screw holes formed on the side surface of the second end block 212 along the width direction Y shown in FIG. 3 . The second end block 212 is fixed to the first side plate 231 by the fastening bolts 241 as shown in FIG. 1 . Similarly, the second end block 212 is fixed to the second side plate 232 by the fastening bolts 241. The second end block 212 is formed with insertion holes 212n for inserting bolts or the like to secure the battery pack 1. The second end block 212 is formed of, for example, metal or resin.

[0026] 4, the insulating member 221 is inserted into the first end block 211. The insulating member 221 is also inserted into the second end block 212. The insulating member 221 is formed, for example, in a rectangular parallelepiped shape. The insulating member 221 is made of an insulating material.

[0027] The insulating member 221 may be configured as follows. That is, the insulating member 221 may be molded integrally with the first end spacer 201, or may be molded separately from the first end spacer 201 and then joined to the first end spacer 201. In such a case, the first end block 211 has a recess on its surface facing the first end spacer 201 that accommodates the insulating member 221 along the stacking direction X. Similarly, the insulating member 221 may be molded integrally with the second end spacer 203, or may be molded separately from the second end spacer 203 and then joined to the second end spacer 203. In such a case, the second end block 212 has a recess on its surface facing the second end spacer 203 that accommodates the insulating member 221 along the stacking direction X.

[0028] 3, the insert nut 222 is embedded in a recess formed in the upper surface of the insulating member 221. A fastening bolt is anchored to the insert nut 222 via a bus bar that is electrically connected to an external control device, for example.

[0029] As shown in FIG. 1 , the first side plate 231 is arranged at one end of the stacked batteries 100 in the width direction Y, along the stacking direction X of the stacked batteries 100. The first side plate 231 holds the batteries 100 along the stacking direction X. Both ends of the first side plate 231 extending along the stacking direction X are bent toward the width direction Y. As shown in FIG. 3 , fastening bolts 241 are inserted into a plurality of insertion holes 231m formed on the side surface of the first side plate 231 along the width direction Y. As shown in FIG. 1 , the first side plate 231 is fixed to the first end block 211 and the second end block 212 by the fastening bolts 241.

[0030] As shown in FIG. 1 , the second side plate 232 is arranged along the stacking direction X of the stacked plurality of batteries 100, at the other end of the plurality of batteries 100 in the width direction Y. The second side plate 232 holds the plurality of batteries 100 along the stacking direction X. Both ends of the second side plate 232 extending along the stacking direction X are bent toward the width direction Y. As shown in FIG. 3 , fastening bolts 241 are inserted into a plurality of insertion holes 232m formed on the side surface of the second side plate 232 along the width direction Y. As shown in FIG. 1 , the second side plate 232 is fixed to the first end block 211 and the second end block 212 by the fastening bolts 241.

[0031] 2, the fastening bolts 241 fasten the first side plate 231 to the first end block 211, and the first side plate 231 to the second end block 212. Also, the fastening bolts 241 fasten the second side plate 232 to the first end block 211, and the second side plate 232 to the second end block 212, as shown in FIG.

[0032] (Configuration of Bus Bar Unit 300) The configuration of the bus bar unit 300 will be described with reference to Figs. 1, 2, and 5 to 14.

[0033] As shown in Fig. 5, the bus bar unit 300 includes a first end bus bar 310, a plurality of bus bars 320, a second end bus bar 330, and a bus bar holder 340. The bus bar 320 shown in Figs. 1, 2, and 5 to 14 electrically connects a plurality of batteries 100. The first end bus bar 310 and the second end bus bar 330 shown in Figs. 1, 2, and 5 electrically connect the batteries 100 and external electrical equipment. The components included in the bus bar unit 300 will be described below.

[0034] (Configuration of First End Bus Bar 310 (Bus Bar)) The configuration of the first end bus bar 310 will be described with reference to FIGS. 1, 2, and 5. FIG.

[0035] As shown in Fig. 2 , for example, of 20 stacked batteries 100, the first end bus bar 310 is joined to the positive electrode terminal 103 of the battery 100 that is closest to the first end block 211. As shown in Fig. 5 , the first end bus bar 310 has a first member 311 and a second member 312. The first end bus bar 310 is formed by solid-state welding, for example, the first member 311 containing copper and the second member 312 containing aluminum.

[0036] (First member 311) The first member 311 is joined to bus bars and wiring that are electrically connected to external electrical equipment. The external electrical equipment is, for example, a relay or a motor provided in an electric vehicle. The first end bus bar 310 may be configured to be joined to a bus bar that connects the battery packs 1 in series or parallel. An insertion hole 311i is formed in the first member 311. A fastening bolt is inserted into the insertion hole 311i. The first member 311 and the bus bars and wiring that are electrically connected to external control equipment are joined by the fastening bolt. The other configurations and materials of the first member 311 are the same as those of the first member 321 of the bus bar 320, which will be described later.

[0037] (Second member 312) The second member 312 is joined to the positive electrode terminal 103 of the battery 100 located at the end along the stacking direction X among, for example, 20 stacked batteries 100. The other configuration and material of the second member 312 are the same as the configuration of the second member 322 of the bus bar 320 described later.

[0038] (Configuration of Bus Bar 320) The configuration of the bus bar 320 will be described with reference to Figs. 1, 2, and 5 to 14.

[0039] 2 , the bus bar 320 electrically connects one battery 100 and another battery 100 that are adjacent to each other along the stacking direction X of the batteries 100. The bus bar 320 is joined to the positive electrode terminal 103 of one battery 100 and the negative electrode terminal 104 of the other battery 100 that is adjacent to the one battery 100 along the stacking direction X.

[0040] As shown in Figures 7 and 8, the bus bar 320 includes a first member 321 and a second member 322 laminated on the first member 321. The first member 321 and the second member 322 include a solid-state welded portion 320A formed by solid-state welding to each other. The bus bar 320 electrically joins, for example, one battery 100 having a negative electrode terminal 104 containing copper to another battery 100 having a positive electrode terminal 103 containing aluminum. Therefore, the bus bar 320 is formed by solid-state welding, for example, the first member 321 containing copper and the second member 322 containing aluminum.

[0041] 7 and 8, the first member 321 includes a first mounting portion 321P, a first bending portion 321Q, and a first joint portion 321R. The first member 321 is integrally formed with the first mounting portion 321P, the first bending portion 321Q, and the first joint portion 321R in this order.

[0042] As shown in FIG. 2 , the first mounting portion 321P is attached to the negative electrode terminal 104 (electrode terminal) of the battery 100. As shown in FIGS. 7 and 8 , the first mounting portion 321P is formed in a plate shape. The first mounting portion 321P has a mounting surface 321a, which is defined by a vibration direction B and a width direction C perpendicular to the vibration direction B, attached to the negative electrode terminal 104. The first mounting portion 321P extends along the vibration direction B. The first mounting portion 321P may have a through-hole. For example, a testing tool is inserted into the through-hole of the first mounting portion 321P and brought into contact with the negative electrode terminal 104 to test the electrical characteristics of the battery 100. The corners of the first mounting portion 321P may be curved or linearly notched. The first mounting portion 321P is, for example, laser-bonded to the negative electrode terminal 104.

[0043] The first bent portion 321Q is a portion bent from an end of the first mounting portion 321P toward the stacking direction A. The first bent portion 321Q is also a portion bent from an end of the first bonding portion 321R toward the stacking direction A. As shown in FIGS. 7 and 8 , the first bent portion 321Q extends along the stacking direction A between the first bonding portion 321R and the first mounting portion 321P. The first bent portion 321Q is perpendicular to the first mounting portion 321P and the first bonding portion 321R. As shown in FIG. 7 , the first bent portion 321Q is formed in a plate shape. A first boundary 321b at the boundary between the first bent portion 321Q and the first mounting portion 321P is formed in an arc shape. A second boundary 321c at the boundary between the first bent portion 321Q and the first bonding portion 321R is formed in an arc shape.

[0044] As shown in FIGS. 7 and 8 , the first bent portion 321Q extends from one end to the other end in the stacking direction A between the first joint portion 321R and the first attachment portion 321P. One end of the first bent portion 321Q is connected to the first attachment portion 321P. The other end of the first bent portion 321Q is connected to the first joint portion 321R. The shape of the first bent portion 321Q extending from one end to the other end in the stacking direction A is such that the first bent portion 321Q extends from one end to the other end in the stacking direction A and then does not fold back from the other end in the stacking direction A to the one end. In other words, the overall shape of the first bent portion 321Q is not U-shaped or the like. The U-shape corresponds to a shape that extends from one end to the other end in the stacking direction A and then folds back from the other end in the stacking direction A to the one end. A part of the overall shape of the first bending portion 321Q may be configured as a U-shape or the like. That is, a part of the region from one end side to the other end side of the first bending portion 321Q may include a U-shape or the like. One end side of the first bending portion 321Q and the other end side of the first bending portion 321Q are not at the same position or relatively close positions along the stacking direction A.

[0045] The first bent portion 321Q causes the position of the solid-state welded portion 320A to differ from the position where it is joined to the negative terminal 104 of the battery 100. The positions are along the height direction Z relative to the positive terminal 103 and the negative terminal 104 of the battery 100. The first bent portion 321Q also suppresses the spring constant of the bus bar 320. Specifically, the first bent portion 321Q relieves stress on the bus bar 320 due to expansion and contraction of the battery 100, vibration of the battery pack 1, and the like. The longer the length of the first bent portion 321Q along the stacking direction A, the smaller the spring constant. The shorter the length of the first bent portion 321Q, the smaller the electrical resistance of the first bent portion 321Q.

[0046] The length of the first bending portion 321Q is, for example, 0.1 mm or more and 50 mm or less. The length of the first bending portion 321Q along the stacking direction A is preferably 1 mm or more and 20 mm or less, and more preferably 2 mm or more and 10 mm or less. The angle of the first bending portion 321Q is 0 degrees with respect to the stacking direction A and 90 degrees with respect to the plane on which the solid-state welding portion 320A is interposed. The angle of the first bending portion 321Q is preferably 30 degrees or more and 150 degrees or less, and more preferably 45 degrees or more and 135 degrees or less. The magnitude of the bending R of the first boundary 321b and the second boundary 321c of the first bending portion 321Q is, for example, 0.001 mm or more and 8 mm or less. The magnitude of the bending R is preferably 0.01 mm or more and 4 mm or less, and more preferably 0.1 mm or more and 2 mm or less.

[0047] As shown in FIGS. 7 and 8 , the first bonding portion 321R is connected to the first bending portion 321Q. The first bonding portion 321R is in contact with the second member 322 in the stacking direction A. As shown in FIG. 7 , the first bonding portion 321R is formed in a plate shape. A surface of the first bonding portion 321R defined by the vibration direction B and the width direction C perpendicular to the vibration direction B is in contact with the second member 322. The first bonding portion 321R extends along the vibration direction B. The first bonding portion 321R does not face the first mounting portion 321P along the stacking direction A. The first bonding portion 321R extends in a direction away from the first mounting portion 321P along the vibration direction B via the first bending portion 321Q. The first bonding portion 321R is formed parallel to the first mounting portion 321P.

[0048] The thinner the first member 321, the more the stress on the solid-state welded portion 320A of the bus bar 320 is alleviated. The thicker the first member 321, the smaller the electrical resistance of the bus bar 320. The thickness of the first member 321 is, for example, 0.1 mm or more and 3 mm or less. The thickness of the first member 321 is preferably 0.3 mm or more and 2 mm or less, and more preferably 0.4 mm or more and 1.5 mm or less. The thickness of the first member 321 may be partially reduced or increased.

[0049] The first member 321 is electrically conductive. The first member 321 has a higher hardness than the second member 322. The hardness can be determined, for example, by the magnitude of Brinell hardness, Vickers hardness, Rockwell hardness, or Shear hardness. The first member 321 has a higher Young's modulus than the second member 322. That is, the first member 321 has a higher rigidity and is less likely to deform than the second member 322. The first member 321 contains, for example, copper or a copper alloy. When the first member 321 is a copper alloy, for example, any of the 1000 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series, and 7000 series alloys is used. The first member 321 may be made of a material that has been subjected to any of the following treatments in the tempering of the copper alloy: F, O, ¼H, ½H, ¾H, H, EH, and SH.

[0050] The first member 321 may be plated. At least the portion of the first member 321 that is to be solid-phase bonded to the second member 322 is plated. Examples of plating include electrolytic nickel plating, electroless nickel plating, tin plating, zinc plating, chromium plating, gold plating, silver plating, copper plating, and rhodium plating. Nickel plating is preferred, and electrolytic nickel plating is more preferred. The plating thickness is, for example, 0.1 μm or more and 100 μm or less. The plating thickness is preferably 0.2 μm or more and 50 μm or less, and more preferably 0.5 μm or more and 10 μm or less. The gloss of the plating is, for example, 0.2 or more and less than 4. The gloss of the plating is preferably 0.3 or more and less than 3, and more preferably 0.6 or more and less than 2.5.

[0051] As shown in FIGS. 7 and 14 , the first member 321 includes a concave recess 321e exposed at a first outer edge 321d. The first outer edge 321d is located at a portion where the first member 321 and the second member 322 are exposed to the outside in the same width direction C that intersects with the stacking direction A. The first outer edge 321d is aligned with the stacking direction X of the battery pack 1. The recess 321e is exposed to the outside of the first member 321 in the direction (width direction C) that intersects with the stacking direction A with the second member 322. As shown in FIG. 9 , the recess 321e is adjacent to the solid-state welded portion 320A in the width direction C. The recess 321e is adjacent to the solid-state welded portion 320A but is spaced apart from it.

[0052] 9, the length of the recess 321e along the first outer edge 321d is equal to or greater than the length of the solid-state welded portion 320A along the first outer edge 321d. The entire region of the recess 321e along the first outer edge 321d faces the solid-state welded portion 320A in a direction intersecting the direction along the first outer edge 321d. The recess 321e of the first member 321 overlaps with the recess 322e of the second member 322 along the stacking direction of the first member 321 and the second member 322.

[0053] 10, the first member 321 includes a first protrusion 321g (protrusion) that protrudes outward from the recess 321e. The first protrusion 321g is a partial deformation of the first member 321 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded. The first protrusion 321g partially protrudes from the first member 321. The first protrusion 321g protrudes from the recess 321e toward the first outer edge 321d.

[0054] 9 and 10 , the tip of the first protrusion 321g of the first member 321 is located closer to the solid-state welded portion 320A than the first outer edge 321d in a direction intersecting the stacking direction A of the first member 321 and the second member 322. The first protrusion 321g is located more inward than the first outer edge 321d in a direction intersecting the stacking direction A (width direction C). The tip of the first protrusion 321g is contained within the recess 321e. The tip of the first protrusion 321g does not protrude beyond the first outer edge 321d in the direction intersecting the stacking direction A (width direction C).

[0055] 10 , the first protrusion 321g of the first member 321 is inclined from the base end toward the tip end toward the second member 322. The tip end of the first protrusion 321g is located closer to the second member 322 than the center (center line D1) of the solid-state welded portion 320A along the vibration direction B. The center line D1 extends linearly along the width direction C and is perpendicular to the vibration direction B.

[0056] 9 and 10 , the first member 321 includes a second outer edge 321f that intersects with the first outer edge 321d. The second protrusion 321h protrudes from the second outer edge 321f of the first member 321 toward the second member 322 along the vibration direction B. As shown in FIG. 7 , the second outer edge 321f is a tip edge that extends from the first member 321 toward the second member 322 in a direction intersecting the stacking direction A (vibration direction B). The second protrusion 321h faces the second member 322 in the stacking direction A.

[0057] As shown in Fig. 7, the first member 321 includes a second protruding portion 321h protruding from the second outer edge 321f. As shown in Figs. 9 and 10, the second protruding portion 321h faces the second member 322 in the stacking direction A. The second protruding portion 321h is a partial deformation of the first member 321 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded. The second protruding portion 321h partially protrudes from the first member 321.

[0058] 7 and 8, the second member 322 includes a second mounting portion 322P, a second bending portion 322Q, and a second joining portion 322R. The second member 322 is integrally formed with the second mounting portion 322P, the second bending portion 322Q, and the second joining portion 322R in this order.

[0059] As shown in FIG. 2 , the second mounting portion 322P is attached to the positive electrode terminal 103 (electrode terminal) of the battery 100. As shown in FIGS. 7 and 8 , the second mounting portion 322P is formed in a plate shape. The second mounting portion 322P has a mounting surface 322a, which is defined by a vibration direction B and a width direction C perpendicular to the vibration direction B, attached to the positive electrode terminal 103. The second mounting portion 322P extends along the vibration direction B. The second mounting portion 322P may have a through-hole. For example, a testing tool is inserted into the through-hole of the second mounting portion 322P and brought into contact with the positive electrode terminal 103 to test the electrical characteristics of the battery 100. The corners of the second mounting portion 322P may be curved or linearly notched. The second mounting portion 322P is, for example, laser-bonded to the positive electrode terminal 103.

[0060] The second bent portion 322Q is a portion bent from an end of the second mounting portion 322P toward the stacking direction A. The second bent portion 322Q is also a portion bent from an end of the second bonding portion 322R toward the stacking direction A. As shown in FIGS. 7 and 8 , the second bent portion 322Q extends along the stacking direction A between the second bonding portion 322R and the second mounting portion 322P. The second bent portion 322Q is perpendicular to the second mounting portion 322P and the second bonding portion 322R. As shown in FIG. 7 , the second bent portion 322Q is formed in a plate shape. A first boundary 322b at the boundary between the second bent portion 322Q and the second mounting portion 322P is formed in an arc shape. A second boundary 322c at the boundary between the second bent portion 322Q and the second bonding portion 322R is formed in an arc shape.

[0061] As shown in FIGS. 7 and 8 , the second bent portion 322Q extends from one end to the other end in the stacking direction A between the second joint portion 322R and the second attachment portion 322P. One end of the second bent portion 322Q is connected to the second attachment portion 322P. The other end of the second bent portion 322Q is connected to the second joint portion 322R. The shape of the second bent portion 322Q extending from one end to the other end in the stacking direction A is such that the second bent portion 322Q extends from one end to the other end in the stacking direction A and then does not fold back from the other end in the stacking direction A to the one end. In other words, the overall shape of the second bent portion 322Q is not U-shaped or the like. The U-shape corresponds to a shape that extends from one end to the other end in the stacking direction A and then folds back from the other end in the stacking direction A to the one end. A part of the overall shape of the second refraction portion 322Q may be configured as a U-shape or the like. That is, a part of the region from one end side to the other end side of the second refraction portion 322Q may include a U-shape or the like. One end side of the second refraction portion 322Q and the other end side of the second refraction portion 322Q are not at the same position or relatively close positions along the stacking direction A.

[0062] The second bent portion 322Q causes the position of the solid-state welded portion 320A to differ from the position where it is joined to the positive terminal 103 of the battery 100. The positions are along the height direction Z relative to the positive terminal 103 and the negative terminal 104 of the battery 100. The second bent portion 322Q also reduces the spring constant of the bus bar 320. Specifically, the second bent portion 322Q relieves stress on the bus bar 320 due to expansion and contraction of the battery 100 and vibration of the battery pack 1. The longer the length of the second bent portion 322Q along the stacking direction A, the smaller the spring constant. The shorter the length of the second bent portion 322Q, the smaller the electrical resistance of the second bent portion 322Q.

[0063] The length of the second bent portion 322Q is, for example, 0.1 mm or more and 50 mm or less. The length of the second bent portion 322Q along the stacking direction A is preferably 1 mm or more and 20 mm or less, and more preferably 2 mm or more and 10 mm or less. The angle of the second bent portion 322Q is 0 degrees with respect to the stacking direction A and 90 degrees with respect to the plane on which the solid-state welded portion 320A is interposed. The angle of the second bent portion 322Q is preferably 30 degrees or more and 150 degrees or less, and more preferably 45 degrees or more and 135 degrees or less. The magnitude of the bending R of the first boundary 322b and the second boundary 322c of the second bent portion 322Q is, for example, 0.001 mm or more and 8 mm or less. The magnitude of the bending R is preferably 0.01 mm or more and 4 mm or less, and more preferably 0.1 mm or more and 2 mm or less.

[0064] As shown in FIGS. 7 and 8 , the second bonding portion 322R is connected to the second bending portion 322Q. The second bonding portion 322R is in contact with the first member 321 in the stacking direction A. As shown in FIG. 7 , the second bonding portion 322R is formed in a plate shape. A surface of the second bonding portion 322R defined by the vibration direction B and the width direction C perpendicular to the vibration direction B is in contact with the first member 321. The second bonding portion 322R extends along the vibration direction B. The second bonding portion 322R does not face the second mounting portion 322P along the stacking direction A. The second bonding portion 322R extends in a direction away from the second mounting portion 322P along the vibration direction B via the second bending portion 322Q. The second bonding portion 322R is formed parallel to the second mounting portion 322P.

[0065] The thinner the second member 322, the more the stress on the solid-state welded portion 320A of the bus bar 320 is alleviated. The thicker the second member 322, the smaller the electrical resistance of the bus bar 320. The thickness of the second member 322 is, for example, 0.1 mm or more and 3 mm or less. The thickness of the second member 322 is preferably 0.3 mm or more and 2 mm or less, and more preferably 0.4 mm or more and 1.5 mm or less. The thickness of the second member 322 may be partially reduced or increased.

[0066] The second member 322 is electrically conductive. The second member 322 has a different rigidity from the first member 321. The second member 322 has a lower hardness than the first member 321. The second member 322 contains, for example, aluminum or an aluminum alloy. When the second member 322 is an aluminum alloy, for example, any of the 1000 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series, 7000 series, and 8000 series alloys is used. For example, the second member 322 is made of a material that has been subjected to any of F, O, H, W, and T treatments in the thermal refining of the aluminum alloy.

[0067] The second member 322 may be plated. At least the portion of the second member 322 that is to be solid-state joined to the first member 321 is plated. The plating applied to the second member 322 is the same as the plating applied to the first member 321.

[0068] As shown in FIGS. 7 and 14 , the second member 322 includes a concave recess 322e exposed at a first outer edge 322d. The first outer edge 322d is located at a portion where the first member 321 and the second member 322 are exposed to the outside in the same width direction C that intersects with the stacking direction A. The first outer edge 322d is aligned with the stacking direction X of the battery pack 1. The recess 322e is exposed to the outside of the second member 322 in the direction (width direction C) that intersects with the stacking direction A with the first member 321. As shown in FIG. 9 , the recess 322e is adjacent to the solid-state welded portion 320A in the width direction C. The recess 322e is adjacent to the solid-state welded portion 320A but is spaced apart from it.

[0069] 9, the length of the recess 322e along the first outer edge 322d is equal to or greater than the length of the solid-state welded portion 320A along the first outer edge 322d. The entire region of the recess 322e along the first outer edge 322d faces the solid-state welded portion 320A in a direction intersecting the direction along the first outer edge 322d. The recess 322e of the second member 322 overlaps with the recess 321e of the first member 321 along the stacking direction of the first member 321 and the second member 322.

[0070] 9, the second member 322 includes a first protrusion 321g (protrusion) protruding outward from the recess 321e. The first protrusion 322g is a partial deformation of the second member 322 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded. The first protrusion 322g partially protrudes from the second member 322. The first protrusion 322g protrudes from the recess 322e toward the first outer edge 322d.

[0071] As shown in FIG. 9 , the tip of the first protrusion 322g of the second member 322 is located closer to the solid-state welded portion 320A than the first outer edge 322d in a direction intersecting the stacking direction A of the first member 321 and the second member 322. The first protrusion 322g is located more inward than the first outer edge 322d in a direction intersecting the stacking direction A (width direction C). The tip of the first protrusion 322g is contained within the recess 322e. The tip of the first protrusion 322g does not protrude beyond the first outer edge 322d in the direction intersecting the stacking direction A (width direction C).

[0072] 12 , the first protrusion 322g of the second member 322 is inclined from the base end toward the tip end toward the first member 321. The tip end side of the first protrusion 322g is located closer to the first member 321 than the center line D1 of the solid-state welded portion 320A along the vibration direction B.

[0073] 11 and 12 , the second member 322 includes a second outer edge 322f that intersects with the first outer edge 322d. The second protruding portion 322h protrudes from the second outer edge 322f of the second member 322 toward the first member 321. As shown in FIG. 7 , the second outer edge 322f is a tip edge that extends from the second member 322 toward the first member 321 in a direction intersecting the stacking direction A (vibration direction B). The second protruding portion 322h faces the first member 321 in the stacking direction A.

[0074] As shown in Fig. 7, the second member 322 includes a second protruding portion 322h protruding from a second outer edge 322f. As shown in Figs. 11 and 12, the second protruding portion 322h faces the first member 321 in the stacking direction A. The second protruding portion 322h is a partial deformation of the second member 322 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded. The second protruding portion 322h partially protrudes from the second member 322.

[0075] (Solid-State Welded Portion 320A of Bus Bar 320) The solid-state welded portion 320A of the bus bar 320 will be described with reference to FIGS. 7 and 8. FIG.

[0076] In the bus bar 320, the first joint 321R of the first member 321 and the second joint 322R of the second member 322 include a solid-state welded portion 320A. The bus bar 320 is solid-state welded at the first joint 321R of the first member 321 and the second joint 322R of the second member 322.

[0077] For example, ultrasonic bonding, which is solid-state bonding using ultrasonic waves, is used for solid-state bonding of the first member 321 and the second member 322. In ultrasonic bonding, the stacked first member 321 and the second member 322 are bonded by applying pressure and vibrating them with a horn and anvil. For solid-state bonding of the first member 321 and the second member 322, friction stir welding may also be used, in which the first member 321 and the second member 322 are softened by frictional heat and then stirred to bond them.

[0078] As shown in FIG. 7 , the solid-state welded portion 320A is formed, for example, in a rectangular shape when viewed from the stacking direction A. The longitudinal direction of the solid-state welded portion 320A is the direction along the width direction C intersecting with the vibration direction B. The lateral direction of the solid-state welded portion 320A is the direction along the vibration direction B. That is, as shown in FIG. 7 , the length of the rectangular solid-state welded portion 320A along the width direction C intersecting with the vibration direction B is longer than the length along the vibration direction B. The longitudinal direction of the solid-state welded portion 320A may be the direction along the vibration direction B, and the lateral direction may be the direction along the width direction C intersecting with the vibration direction B. In this case, the length of the rectangular solid-state welded portion 320A along the vibration direction B is longer than the length along the width direction C intersecting with the vibration direction B. The solid-state welded portion 320A may also be square. In this case, the square solid-state welded portion 320A has a length in the direction along the vibration direction B that is equal to a length in the width direction C that intersects with the vibration direction B.

[0079] The solid-state welded portion 320A may be a circle, an ellipse, a parallelogram, a trapezoid, a rhombus, a hexagon, an octagon, or any other polygonal shape. The solid-state welded portion 320A may be an arbitrary geometric shape. The solid-state welded portion 320A may be a shape formed by the maximum area of ​​a trajectory defined by sliding an arbitrary geometric shape in a linear or rotational direction. The solid-state welded portion 320A may be a shape that is a part of the shape formed by the maximum area.

[0080] (Configuration of Second End Bus Bar 330) The configuration of the second end bus bar 330 will be described with reference to Figs. 1, 2 and 5 .

[0081] As shown in Fig. 2 , for example, of 20 stacked batteries 100, the second end bus bar 330 is joined to the negative electrode terminal 104 of the battery 100 that is closest to the second end block 212. As shown in Fig. 5 , the second end bus bar 330 has a first portion 331 and a second portion 332.

[0082] In the second end bus bar 330, the first portion 331 is joined to the negative terminal 104 of the battery 100. The first portion 331 is an electrical device, and a bus bar that is electrically connected to an external control device is joined to the first portion 331. In the first end bus bar 310, the first member 311 is joined to a bus bar or wiring that is electrically connected to an external electrical device. The external electrical device is, for example, a relay or a motor provided in an electric vehicle. The second end bus bar 330 may be configured to be joined to a bus bar that connects the battery packs 1 in series or parallel. An insertion hole 311i is formed in the second portion 332. A fastening bolt is inserted into the insertion hole 332i. The second portion 332 is joined to the bus bar or wiring that is electrically connected to the external control device by the fastening bolt. The second portion 332 is formed integrally with the first portion 331. The second end bus bar 330 is formed of, for example, copper.

[0083] (Configuration of busbar holder 340 (holding member)) As shown in Figures 1, 5 and 6, the busbar holder 340 (holding member) integrally holds the first end busbar 310, the plurality of busbars 320 and the second end busbar 330. The busbar holder 340 also covers the stacked plurality of batteries 100 to insulate the batteries 100 from surrounding components. As shown in Figure 5, the busbar holder 340 includes a plurality of openings 340a, a plurality of holding portions 340c, a plurality of fixing portions 340b and a plurality of insertion portions 340d. The busbar holder 340 is formed in a plate shape.

[0084] 5 and 6 , the openings 340a expose the first joint portions or second joint portions of the first end bus bar 310, the bus bars 320, and the second end bus bar 330 downward in the height direction Z. The positive terminal 103 or the negative terminal 104 of the battery 100 is inserted into each opening 340a toward the upward side in the height direction Z.

[0085] As shown in FIGS. 5 and 6 , the multiple fixing portions 340b hold the ends of the first joint portions or second joint portions of the first end bus bar 310, the multiple bus bars 320, and the second end bus bar 330. Each fixing portion 340b is formed on the edge of the opening 340a. Each fixing portion 340b has a linear groove along the surface of the bus bar holder 340. An end of the first joint portion or second joint portion of the corresponding bus bar is inserted into the groove provided in each fixing portion 340b. The shape of the fixing portions 340b is not limited as long as it can hold the bus bar 320, the first end bus bar 310, and the second end bus bar 330.

[0086] As shown in FIGS. 5 and 6 , the plurality of holding portions 340c are formed on both edges of the opening 340a in the width direction Y. Each holding portion 340c extends along the stacking direction X. The holding portions 340c hold the first end bus bar 310 along the first outer edge of the first member 311 and the first outer edge of the second member 312 of the first end bus bar 310. The pair of holding portions 340c hold the bus bar 320 by sandwiching the first end bus bar 310 from both sides in the width direction Y. The holding portions 340c hold the bus bar 320 along the first outer edge 321d of the first member 321 and the first outer edge 322d of the second member 322 of the bus bar 320. The pair of holding portions 340c hold the bus bar 320 by sandwiching the bus bar 320 from both sides in the width direction Y. The holding portions 340c hold the second end bus bar 330 along the first outer edge of the first portion 331 and the first outer edge of the second portion 332 of the second end bus bar 330. The pair of holding portions 340c hold the bus bar 320 by sandwiching the second end bus bar 330 from both sides in the width direction Y. The shape of the holding portions 340c is not limited as long as they hold the bus bar 320, the first end bus bar 310, and the second end bus bar 330 along the first outer edges.

[0087] As shown in FIGS. 1 and 2, the electric wires 502 of the temperature measuring unit 500 are inserted into the multiple insertion portions 340d.

[0088] (Configuration of voltage detection unit 400) The voltage detection unit 400 shown in Figures 1, 2, 5 and 6 detects the voltage of the battery 100 based on control by, for example, an external control device. As shown in Figure 5, the voltage detection unit 400 includes a voltage detection terminal 401 and an electric wire 402. The configuration included in the voltage detection unit 400 will be described below.

[0089] 5 , the voltage detection terminal 401 is conductive and formed in a plate shape. The voltage detection terminal 401 is joined to the first end bus bar 310, the plurality of bus bars 320, and the second end bus bar 330 of the bus bar unit 300, respectively.

[0090] 5, the electric wire 402 is joined to the voltage detection terminal 401. The electric wire 402 provides electrical continuity between the voltage detection terminal 401 and an external control device.

[0091] (Configuration of temperature measurement unit 500) The temperature measurement unit 500 shown in Figures 1, 2 and 5 measures the temperature of the battery 100 based on control by, for example, an external control device. As shown in Figure 2, the temperature measurement unit 500 includes a temperature sensor 501 and an electric wire 502. The configuration included in the temperature measurement unit 500 will be described below.

[0092] The temperature sensors 501 measure the temperature of the batteries 100. As shown in FIG. 2 , for example, the temperature sensors 501 are joined to the lids 102 of the seventh and fourteenth batteries 100 from the first end block 211 to the second end block 212.

[0093] 2, the electric wire 502 is attached to the temperature sensor 501. The electric wire 502 provides electrical continuity between the temperature sensor 501 and an external control device.

[0094] (Advantages of the Bus Bar 320, etc. and the Battery Pack 1 of the First Embodiment) Advantages of the bus bar 320, etc. and the battery pack 1 of the first embodiment will be described with reference to FIGS. 1, 2, and 5 to 14. FIG.

[0095] (1) As shown in FIGS. 7 and 10 , the bus bar 320 includes a first member 321 and a second member 322 stacked on the first member 321. The first member 321 and the second member 322 are solid-state welded to each other to form a solid-state welded portion 320A. The first member 321 includes a concave recess 321e exposed at a first outer edge 321d (outer edge). The second member 322 includes a concave recess 322e exposed at a first outer edge 322d (outer edge). The recess 321e and the recess 322e are adjacent to the solid-state welded portion 320A. In the first embodiment, both the first member 321 and the second member 322 include a recess. In the present invention, it is sufficient that at least one of the first member 321 and the second member 322 includes a recess.

[0096] (19) As shown in FIGS. 1 and 2 , the battery pack 1 includes the battery 100 and the bus bar 320 connected to the battery 100 .

[0097] With this configuration, in a busbar 320 formed by solid-state welding of a first member 321 and a second member 322 (two or more members), the recesses 321e and 322e can suppress or prevent the influence of the solid-state welded portion 320A on the external dimensions of the busbar 320. As a result, the busbar 320 can satisfy the allowable dimensions based on the design values. That is, when the first member 321 and the second member 322 (two or more members) are solid-state welded, the busbar 320 can be obtained such that the upper limits of the external dimensions of the first member 321 and the second member 322 satisfy a predetermined range. Furthermore, with this configuration, a battery pack 1 including the busbar 320 can be obtained. The configuration and effects of the busbar 320 can also be applied to the first end busbar 310. The influence of the solid-state welded portion 320A on the external dimensions of the busbar 320 is, for example, partial deformation of the first member 321 or the second member 322 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded. The partial deformation is such that, when the solid-state welded portion 320A is formed, a part of the solid-state welded portion 320A is pushed out toward the recess 321 e or the recess 322 e.

[0098] (2) In the bus bar 320, the recess 321e of the first member 321 and the recess 322e of the second member 322 are adjacent to each other while being spaced apart from the solid-state welded portion 320A, as shown in FIGS. 7 and 9. In the first embodiment, the recesses of both the first member 321 and the second member 322 are adjacent to each other while being spaced apart from the solid-state welded portion 320A. In the present invention, it is sufficient that the recess of at least one of the first member 321 and the second member 322 is adjacent to each other while being spaced apart from the solid-state welded portion 320A.

[0099] With this configuration, even if the region between the recess 321 e of the first member 321 and the solid-state welded portion 320A is pushed toward the recess 321 e when the solid-state welded portion 320A is formed, this can be absorbed by the space inside the recess 321 e. Furthermore, with this configuration, even if the region between the recess 322 e of the second member 322 and the solid-state welded portion 320A is pushed toward the recess 322 e when the solid-state welded portion 320A is formed, this can be absorbed by the space inside the recess 322 e.

[0100] (3) In the busbar 320, the first member 321 includes a first protrusion 321g (protrusion) that protrudes outward from the recess 321e, as shown in FIGS. 7 and 10 . The second member 322 includes a first protrusion 322g (protrusion) that protrudes outward from the recess 322e. In the first embodiment, both the first member 321 and the second member 322 include a protrusion that protrudes outward from the recess. In the present invention, it is sufficient that at least one of the first member 321 and the second member 322 includes a protrusion that protrudes outward from the recess.

[0101] The first protrusion 321g of the first member 321 is a partial deformation of the first member 321 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded together. The first protrusion 321g partially protrudes from the recess 321e of the first member 321. The first protrusion 322g of the second member 322 is a partial deformation of the second member 322 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded together. The first protrusion 322g partially protrudes from the recess 322e of the second member 322.

[0102] According to this configuration, in the first member 321, the first protruding portion 321g protruding from the recess 321e is unlikely to protrude beyond the first outer edge 321d toward the outside of the first member 321 because the recess 321e is located more inward of the first member 321 than the first outer edge 321d. Also, according to this configuration, in the second member 322, the first protruding portion 322g protruding from the recess 322e is unlikely to protrude beyond the first outer edge 322d toward the outside of the second member 322 because the recess 322e is located more inward of the second member 322 than the first outer edge 322d. As a result, the upper limit value of the outer dimension of the busbar 320 can satisfy the predetermined range.

[0103] (4) In the bus bar 320, as shown in FIGS. 7 and 10 , the tip of the first protrusion 321g (protrusion) of the first member 321 is located closer to the solid-state welded portion 320A than the first outer edge 321d in a direction (width direction C) intersecting the stacking direction A of the first member 321 and the second member 322. As shown in FIGS. 7 and 10 , the tip of the first protrusion 322g (protrusion) of the second member 322 is located closer to the solid-state welded portion 320A than the first outer edge 322d in a direction (width direction C) intersecting the stacking direction A of the first member 321 and the second member 322. In the first embodiment, both the first member 321 and the second member 322 have the above-described configuration. In the present invention, it is sufficient that at least one of the first member 321 and the second member 322 has the above-described configuration.

[0104] This configuration can sufficiently prevent the bus bar 320 from interfering with surrounding members, such as the holding portion 340c of the bus bar holder 340 when extended in the height direction Z.

[0105] (5) In the bus bar 320, the first protrusion 321g of the first member 321 is inclined toward the second member 322 from the base end to the tip end as shown in Fig. 10 . The first protrusion 322g of the second member 322 is inclined toward the first member 321 from the base end to the tip end as shown in Fig. 10 . In the first embodiment, both the first member 321 and the second member 322 have the above configuration. In the present invention, it is possible that either the first member 321 or the second member 322 has the above configuration.

[0106] This configuration shows an example of the deformation state of the first protrusion 321g in the first member 321 due to plastic deformation of the solid-state welded portion 320A. In the first member 321, the first joint portion 321R has a first bent portion 321Q on the base end side, but nothing on the tip end side. The tip end side of the first joint portion 321R is the side where the second outer edge 321f is located. The tip end side of the first joint portion 321R, where nothing is present, is relatively more susceptible to deformation than the base end side where the first bent portion 321Q is present. When the first member 321 and the second member 322 are solid-state welded, the first protrusion 321g is more likely to deform and protrude toward the tip end side than the base end side, so it is formed to be inclined toward the tip end side. When the first protrusion 321g is formed at an angle in the recess 321e, the protrusion length of the first protrusion 321g in the width direction C in the recess 321e can be reduced. This configuration also shows an example of the deformation state of the first protrusion 322g in the second member 322 due to plastic deformation of the solid-phase welded portion 320A.

[0107] (6) As shown in FIGS. 7 and 10 , the length of the recess 321e of the first member 321 along the first outer edge 321d is equal to or greater than the length of the solid-state welded portion 320A along the first outer edge 321d. The entire region of the recess 321e along the first outer edge 321d faces the solid-state welded portion 320A in a direction intersecting the direction along the first outer edge 321d. As shown in FIGS. 7 and 10 , the length of the recess 322e of the second member 322 along the first outer edge 322d is equal to or greater than the length of the recess 322e of the solid-state welded portion 320A along the first outer edge 322d. The entire region of the recess 322e along the first outer edge 322d faces the solid-state welded portion 320A in a direction intersecting the direction along the first outer edge 322d. In the first embodiment, both the first member 321 and the second member 322 have the above-described configuration. In the present invention, it is sufficient that at least one of the first member 321 and the second member 322 has the above-described configuration.

[0108] According to this configuration, the recess 321e of the first member 321 and the recess 322e of the second member 322 are positioned next to the solid-state welded portion 320A along the vibration direction B. Furthermore, the recess 321e of the first member 321 and the recess 322e of the second member 322 have a width along the vibration direction B greater than that of the solid-state welded portion 320A. Therefore, it is possible to adequately cope with deformation of the recess 321e of the first member 321 and the recess 322e of the second member 322 that occurs due to plastic deformation of the solid-state welded portion 320A.

[0109] (7) In the bus bar 320, the first member 321 and the second member 322 each include a recess, as shown in FIG.

[0110] With this configuration, the impact on the external dimensions of the busbar 320 caused by the solid-state welded portion 320A can be suppressed or prevented by both the recess 321e of the first member 321 and the recess 322e of the second member 322.

[0111] (8) As shown in Fig. 10 , the recesses 321e of the first member 321 and the recesses 322e of the second member 322 overlap along the stacking direction of the first member 321 and the second member 322. In the first embodiment, the recesses 321e of the first member 321 and the recesses 322e of the second member 322 completely overlap within the range of manufacturing error. In the present invention, it is sufficient that the recesses 321e of the first member 321 and the recesses 322e of the second member 322 at least partially overlap.

[0112] According to this configuration, the influence of the solid-state welded portion 320A on the external dimensions of the bus bar 320 can be suppressed or prevented in one and the same region.

[0113] (9) In the busbar 320, as shown in FIG. 9 , the first member 321 includes a second outer edge 321f intersecting with the first outer edge 321d and a second protruding portion 321h protruding from the second outer edge 321f. The second protruding portion 321h of the first member 321 protrudes from the second outer edge 321f of the first member 321 toward the second member 322 along the vibration direction B. As shown in FIG. 11 , the second member 322 includes a second outer edge 322f intersecting with the first outer edge 322d and a second protruding portion 322h protruding from the second outer edge 322f. The second protruding portion 322h of the second member 322 protrudes from the second outer edge 322f of the second member 322 toward the first member 321. In the first embodiment, both the first member 321 and the second member 322 have the above-described configuration. In the present invention, it is sufficient that at least one of the first member 321 and the second member 322 has the above-described configuration.

[0114] The second protrusion 321h of the first member 321 is a partial deformation of the first member 321 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded. The second protrusion 321h partially protrudes from the first member 321. The second protrusion 322h of the second member 322 is a partial deformation of the second member 322 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 321 and the second member 322 are solid-state welded in the first embodiment. The second protrusion 322h partially protrudes from the second member 322.

[0115] This configuration can disperse the influence of the solid-state welded portion 320A in the busbar 320 formed by solid-state welding the first member 321 and the second member 322. That is, when the second protrusion 321h is formed in the first member 321, the size of the first protrusion 321g protruding from the recess 321e in the width direction C may be reduced. Also, when the second protrusion 322h is formed in the second member 322, the size of the first protrusion 322g protruding from the recess 322e in the width direction C may be reduced.

[0116] (20) As shown in FIG. 6 , the battery pack 1 has a busbar holder 340 (holding member). The busbar holder 340 contacts the first outer edge 321 d (outer edge) of the first member 321 of the busbar 320 and the first outer edge 322 d (outer edge) of the second member 322 of the busbar 320 to hold the busbar 320. The busbar holder 340 contacts the first outer edge (outer edge) of the first member 311 of the first end busbar 310 and the first outer edge (outer edge) of the second member 312 to hold the first end busbar 310. In the first embodiment, for example, both the first outer edge 321 d and the first outer edge 322 d of the busbar 320 are held by the busbar holder 340. In the present invention, for example, it is sufficient that at least one of the first outer edge 321 d and the first outer edge 322 d of the busbar 320 is held by the busbar holder 340.

[0117] With this configuration, for example, when attaching the busbar 320 to the busbar holder 340, it is possible to suppress or prevent interference between the holding portion 340c of the busbar holder 340 and the first outer edge 321d of the first member 321 of the busbar 320. Furthermore, with this configuration, it is possible to suppress or prevent interference between the holding portion 340c of the busbar holder 340 and the first outer edge 322d of the second member 322 of the busbar 320.

[0118] (Bus Bar 610 of Second Embodiment) (Configuration of Bus Bar 610 of Second Embodiment) The configuration of the bus bar 610 will be described with reference to FIGS. 15 and 16. FIG.

[0119] Fig. 15 is a top view showing a main part of a bus bar 610 according to the second embodiment, and Fig. 16 is a bottom view showing the bus bar 610 of Fig. 15 .

[0120] The recess 611e of the first member 611 continuously narrows in the width direction C toward the second member 612. That is, the recess 611e continuously narrows in the width direction C from the base end 611e1 toward the tip 611e2. The recess 611e is inclined toward the inside of the busbar 610 toward the second member 612. The recess 611e is formed along the vibration direction B of the first mounting portion 611P. The recess 611e is formed along the vibration direction of the first bent portion 611Q and the first joint portion 611R. The recess 611e corresponds to a configuration in which the first outer edge 321d is notched at an angle in the first bent portion 611Q and the first joint portion 611R. The first joint portion 611R is formed into a relatively small trapezoidal shape toward the second member 612 by the pair of inclined recesses 611e.

[0121] Due to the recess 611e, the dimension of the first member 611 in the width direction C narrows toward the tip side of the first member 611. The tip side of the first member 611 is the side of the second outer edge 611f. The first protrusion 611g (protrusion) is formed in the recess 611e. The second outer edge 611f is linearly inclined from both sides of the first member 611 in the width direction C toward the center. The second outer edge 611f forms two slopes of an isosceles triangle. The second outer edge 611f does not have to be symmetrical along the width direction C. The second protrusion 611h is formed on each slope of the second outer edge 611f.

[0122] The recess 612e of the second member 612 continuously narrows in the width direction C toward the first member 611. That is, the recess 612e continuously narrows in the width direction C from the base end 612e1 toward the tip 612e2. The recess 612e is inclined toward the inside of the busbar 610 toward the first member 611. The recess 612e is formed along the vibration direction B of the second mounting portion 612P. The recess 612e is formed along the vibration direction of the second bent portion 612Q and the second joint portion 612R. The recess 612e corresponds to a configuration in which the first outer edge 312d is notched at an angle in the second bent portion 612Q and the second joint portion 612R. The second joint portion 612R is formed into a relatively small trapezoidal shape toward the first member 611 by the pair of inclined recesses 612e.

[0123] Due to the recess 612e, the dimension of the second member 612 in the width direction C narrows toward the tip side of the second member 612. The tip side of the second member 612 is the side of the second outer edge 612f. A first protrusion 612g (protrusion) is formed in the recess 612e. The second outer edge 612f is linearly inclined from both sides of the second member 612 in the width direction C toward the center. The second outer edge 612f forms two slopes of an isosceles triangle. The second outer edge 612f does not have to be symmetrical along the width direction C. A second protrusion 612h is formed on each slope of the second outer edge 612f.

[0124] (Effects of Bus Bar 610 of Second Embodiment) The effects of the bus bar 610 will be described with reference to FIGS. 15 and 16. FIG.

[0125] (10) In the bus bar 610, the recess 611e of the first member 611 is continuously tapered in the width direction C intersecting the first outer edge 611d from the first member 611 toward the second member 612. In the present invention, the recess 611e of the first member 611 only needs to include a portion in which the width in the direction intersecting the first outer edge 611d is relatively narrowed from the first member 611 toward the second member 612. The recess 611e of the second member 612 is continuously tapered in the width direction C intersecting the first outer edge 612d from the second member 612 toward the first member 611. In the present invention, the recess 612e of the second member 612 only needs to include a portion in which the width in the direction intersecting the first outer edge 612d is relatively narrowed from the second member 612 toward the first member 611. In the present invention, it is sufficient that only the recessed portion of either the first member or the second member has the above-described configuration.

[0126] This configuration is an example that takes into account the deformation of the first protrusion 611g in the first member 611 due to plastic deformation of the solid-state welded portion 320A. In the first member 611, the first joint 611R has a first bent portion 611Q on the base end side, but nothing on the tip end side. The tip end side of the first joint 611R is the side where the second outer edge 611f is located. The tip end side of the first joint 611R, where nothing is present, is relatively more susceptible to deformation than the base end side where the first bent portion 611Q is present. In other words, when the first member 611 and the second member 612 are solid-state welded together, the first protrusion 611g is more likely to protrude from the tip 611e2 of the recess 611e in the first joint 611R than from the base end 611e1. For this reason, the recess 611e continuously narrows from the base end 611e1 side toward the tip 611e2 side in the width direction C. This configuration is an example that takes into consideration the deformation state of the first protrusion 612g in the second member 612, which is caused by plastic deformation of the solid-state welded portion 320A.

[0127] (Bus Bar 620 of Third Embodiment) (Configuration of Bus Bar 620 of Third Embodiment) The configuration of the bus bar 620 will be described with reference to FIGS. 17 and 18 .

[0128] Fig. 17 is a top view showing a main part of a bus bar 620 according to the third embodiment, and Fig. 18 is a bottom view showing the bus bar 620 of Fig. 17 .

[0129] The recess 621e of the first member 621 has a shape obtained by curving the recess 321e of the first member 321 shown in FIGS. 9 and 10 toward the inside of the first member 621. The inside of the first member 621 is the side of the solid-state welded portion 320A. The recess 621e is curved concavely toward the center of the solid-state welded portion 320A. The center of the solid-state welded portion 320A is the center (center line D1) of the solid-state welded portion 320A along the vibration direction B. The center line D1 extends linearly along the width direction C and is perpendicular to the vibration direction B. As shown in FIG. 17, the recess 621e is formed in an arc shape. The most recessed region of the recess 621e overlaps with the center line D1. The recess 621e is curved toward the center of the solid-state welded portion 320A. The recess 621e is recessed at an angle toward the center of the solid-state welded portion 320A. The recess 621e may be recessed at an angle toward the center of the solid-state welded portion 320A. An inclined recess is, for example, a recess having two sides and linearly recessed toward the center of the solid-state welded portion 320A. The first protrusion 621g (protrusion) protrudes from the center of the recess 321e toward the first outer edge 321d. The tip of the first protrusion 621g is located closer to the solid-state welded portion 320A than the first outer edge 321d along the width direction C.

[0130] The second outer edge 621f of the first member 621 has a shape obtained by curving the second outer edge 321f of the first member 321 shown in FIGS. 9 and 10 toward the center of the solid-state welded portion 320A. The second outer edge 621f is curved concavely toward the center of the solid-state welded portion 320A. The center of the solid-state welded portion 320A is the center (center line D2) of the solid-state welded portion 320A along the width direction C. The center line D2 extends linearly along the vibration direction B and is perpendicular to the width direction C. The second outer edge 621f is formed in an arc shape as shown in FIG. 17. The most concave region of the second outer edge 621f overlaps with the center line D2. The second outer edge 621f is curved toward the center of the solid-state welded portion 320A. The second outer edge 621f may be concave and inclined toward the center of the solid-state welded portion 320A. The second protrusion 621h protrudes from the second outer edge 621f along the vibration direction B toward the second member 622 side.

[0131] The recess 622e of the second member 622 has a shape obtained by curving the recess 322e of the second member 322 shown in FIGS. 9 and 10 toward the inside of the second member 622. The inside of the second member 622 is the side of the solid-state welded portion 320A. The recess 622e is curved concavely toward the center of the solid-state welded portion 320A. As shown in FIG. 18, the recess 622e is formed in an arc shape. The most concave region of the recess 622e overlaps with the center line D1. The recess 622e is curved toward the center of the solid-state welded portion 320A. The recess 622e is concave and inclined toward the center of the solid-state welded portion 320A. The recess 622e may be concave and inclined toward the center of the solid-state welded portion 320A. The inclined recess has, for example, two sides and is linearly concave toward the center of the solid-state welded portion 320A. The first protrusion 622g (protrusion) protrudes from the center of the recess 621e toward the first outer edge 322d. The tip of the first protrusion 622g is located closer to the solid-state welded portion 320A than the first outer edge 322d along the width direction C.

[0132] The second outer edge 622f of the second member 622 has a shape obtained by curving the second outer edge 622f of the second member 622 shown in FIGS. 9 and 10 toward the center of the solid-state welded portion 320A. The second outer edge 622f is curved concavely toward the center of the solid-state welded portion 320A. The center of the solid-state welded portion 320A is the center (center line D2) of the solid-state welded portion 320A along the width direction C. The second outer edge 622f is formed in an arc shape, as shown in FIG. 18. The most concave region of the second outer edge 622f overlaps with the center line D2. The second outer edge 622f is curved toward the center of the solid-state welded portion 320A. The second outer edge 622f may be concave and inclined toward the center of the solid-state welded portion 320A. The second protrusion 622h protrudes from the second outer edge 622f toward the first member 621 along the vibration direction B.

[0133] (Effects of Bus Bar 620 of Third Embodiment) The effects of the bus bar 620 will be described with reference to FIGS. 17 and 18. FIG.

[0134] (11) The recess 621e of the first member 621 is curved and recessed toward the center (center line D1) of the solid-state welded portion 320A. The recess 621e of the first member 621 may be configured to include a portion recessed toward the center of the solid-state welded portion 320A, i.e., may be configured to be partially recessed. The recess 622e of the second member 622 is curved and recessed toward the center of the solid-state welded portion 320A. The recess 622e of the second member 622 may be configured to include a portion recessed toward the center (center line D1) of the solid-state welded portion 320A, i.e., may be configured to be partially recessed. Only the recess of either the first member 621 or the second member 622 may have the above configuration.

[0135] With this configuration, the recess 621e of the first member 621 can suppress or prevent the influence of the solid-state welded portion 320A on the external dimensions of the bus bar 620. The influence of the solid-state welded portion 320A on the external dimensions of the bus bar 620 is, for example, partial deformation of the first member 621 or the second member 622 that occurs due to plastic deformation of the solid-state welded portion 320A when the first member 621 and the second member 622 are solid-state welded. The partial deformation is such that a portion of the solid-state welded portion 320A is pushed toward the recess 621e or the recess 622e when the solid-state welded portion 320A is formed. An example of the partial deformation is the first protrusion 621g. The recess 621e of the first member 621 is curved and recessed toward the center (center line D1) of the solid-state welded portion 320A. Therefore, when the center (center line D1) of the solid-state welded portion 320A undergoes a relatively large deformation, the deformation is caused by a partial deformation of the solid-state welded portion 320A. This can suppress or prevent the influence on the outer dimensions of the busbar 620. The effect of the recess 622e in the second member 622 is similar to the effect of the recess 621e in the first member 621.

[0136] (Bus Bar 630 of Fourth Embodiment) (Configuration of Bus Bar 630 of Fourth Embodiment) The configuration of the bus bar 630 will be described with reference to FIG. 19 .

[0137] FIG. 19 is a perspective view showing a main part of a bus bar 630 according to the fourth embodiment.

[0138] In the first member 631, the recess 321e and the second outer edge 321f are adjacent to each other via a recess 631m recessed toward the solid-state welded portion 320A. The recess 631m is formed by an inclined surface inclined toward the first outer edge 321d and the second outer edge 321f. The recess 631m may be curved in an arc toward the solid-state welded portion 320A.

[0139] In the second member 632, the recess 322e and the second outer edge 322f are adjacent to each other via a recess 632m recessed toward the solid-state welded portion 320A. The recess 632m is formed by an inclined surface inclined with respect to the first outer edge 322d and the second outer edge 322f. The recess 632m may be curved in an arc shape toward the solid-state welded portion 320A.

[0140] (Effects of Bus Bar 630 of Fourth Embodiment) The effects of the bus bar 630 will be described with reference to FIG.

[0141] (12) In the first member 631, the recess 321e and the second outer edge 321f are adjacent to each other via a recess 631m recessed toward the solid-state welded portion 320A. In the second member 632, the recess 322e and the second outer edge 322f are adjacent to each other via a recess 632m recessed toward the solid-state welded portion 320A. Only one of the first member 631 and the second member 632 may have the above configuration.

[0142] With this configuration, in the first member 631, the first protrusion 321g and the second protrusion 321h protruding from the solid-state welded portion 320A can be suppressed or prevented from protruding outward from the boundary between the recess 321e and the second outer edge 321f beyond the first outer edge 321d. The presence of the recess 631m relatively increases the distance to the first outer edge 321d. The effect of the recess 632m in the second member 632 is similar to the effect of the recess 631m in the first member 631.

[0143] (Bus Bar 640 of Fifth Embodiment) (Configuration of Bus Bar 640 of Fifth Embodiment) The configuration of the bus bar 640 will be described with reference to FIG. 20 .

[0144] FIG. 20 is a perspective view showing a main part of a bus bar 640 according to the fifth embodiment.

[0145] In the first member 641, an outer edge 641d of a portion facing the recess 641e in a direction intersecting the stacking direction A is inclined with respect to the stacking direction A. The outer edge 641d of the first member 641 is inclined toward the side approaching the solid-state welded portion 320A of the first member 641 in the direction away from the second member 642 in the stacking direction. The second outer edge 641f of the first member 641 is also inclined toward the side approaching the solid-state welded portion 320A of the first member 641 in the direction away from the second member 642 in the stacking direction. The outer edge 641d and the second outer edge 641f of the first member 641 may be inclined toward the side away from the solid-state welded portion 320A of the first member 641 in the direction away from the second member 642 in the stacking direction.

[0146] In the second member 642, an outer edge 642d of a portion facing the recess 642e in a direction intersecting the stacking direction A is inclined with respect to the stacking direction A. The outer edge 642d of the second member 642 is inclined toward the side approaching the solid-state welded portion 320A of the second member 642, with respect to the direction away from the first member 641 along the stacking direction. A second outer edge of the second member 642 is also inclined toward the side approaching the solid-state welded portion 320A of the second member 642, with respect to the direction away from the first member 641 along the stacking direction. The outer edge 642d and the second outer edge of the second member 642 may be inclined toward the side away from the solid-state welded portion 320A of the second member 642, with respect to the direction away from the first member 641 along the stacking direction.

[0147] (Effects of Bus Bar 640 of Fifth Embodiment) The effects of the bus bar 640 will be described with reference to FIG.

[0148] (13) In the first member 641, the side surface 641e1 of the recess 641e is inclined from the stacking direction A of the first member 641 and the second member 642 toward the solid-state welded portion 320A. In the second member 642, the side surface 642e1 of the recess 642e is inclined from the stacking direction A of the first member 641 and the second member 642 toward the solid-state welded portion 320A. At least the outer edge 641d of the portion facing the recess 641e in a direction intersecting the stacking direction A is inclined from the stacking direction A. In the second member 642 including the recess 642e, at least the outer edge 642d of the portion facing the recess 642e in a direction intersecting the stacking direction A is inclined from the stacking direction A. For only one of the first member 641 or the second member 642, at least the outer edge of the portion facing the recess in a direction intersecting the stacking direction A may be inclined from the stacking direction A.

[0149] According to this configuration, it is possible to suppress or prevent the first protrusion 641g protruding from the solid-state welded portion 320A from protruding beyond the first outer edge 321d in the inclined recess 641e of the first member 641. The effect of the recess 642e in the second member 642 is similar to the effect of the recess 641e in the first member 641.

[0150] (Bus Bar 650 of Sixth Embodiment) (Configuration of Bus Bar 650 of Sixth Embodiment) The configuration of the bus bar 650 will be described with reference to FIG. 21 .

[0151] FIG. 21 is a perspective view showing a main part of a bus bar 650 according to the sixth embodiment.

[0152] The first member 651 includes a recess 651e in a region where the first member 651 and the second member 652 are stacked. The recess 651e is formed only in the first joint portion 321R among the first mounting portion 321P, the first bent portion 321Q, and the first joint portion 321R of the first member 651. The second member 652 includes a recess 652e in a region where the first member 651 and the second member 652 are stacked. The recess 652e is formed only in the second joint portion 322R among the second mounting portion 322P, the second bent portion 322Q, and the second joint portion 322R of the second member 652.

[0153] (Effects of Bus Bar 650 of Sixth Embodiment) The effects of the bus bar 650 will be described with reference to FIG.

[0154] The first member 651 includes a recess 651e in at least the region where the first member 651 and the second member 652 are stacked. The second member 652 includes a recess 652e in at least the region where the first member 651 and the second member 652 are stacked. At least one of the first member 651 and the second member 652 may include a recess in the above region.

[0155] With this configuration, the size of the recess 651e can be relatively small in the first member 651. By providing the recess 651e only in the stacked region, the size of the recess 651e can be smaller than when a recess is provided from the first mounting portion 321P to the stacked region. The effect of the recess 652e in the second member 652 is similar to the effect of the recess 651e in the first member 651. By providing the recess 652e only in the stacked region, the size of the recess 652e can be smaller than when a recess is provided from the second mounting portion 322P to the stacked region.

[0156] (Bus Bar 660 of Seventh Embodiment) (Configuration of Bus Bar 660 of Seventh Embodiment) The configuration of the bus bar 660 will be described with reference to FIG. 22 .

[0157] FIG. 22 is a top view showing a main part of a bus bar 660 according to the seventh embodiment.

[0158] The tip of the first protrusion 662g of the second member 662 protrudes beyond the first outer edge 322d in a direction (width direction C) intersecting the stacking direction A. The first protrusion 662g is larger than the first protrusion 661g of the first member 661. The first protrusion 662g protrudes outward from the recess 322e along the width direction C.

[0159] (Effects of Bus Bar 660 of Seventh Embodiment) The effects of the bus bar 660 will be described with reference to FIG.

[0160] (14) The tip of the first protrusion 662g of the second member 662 protrudes beyond the first outer edge 322d (outer edge) in the direction (width direction C) intersecting the stacking direction A. The first protrusion 661g of the first member 661 may also protrude beyond the first outer edge 321d in the direction (width direction C) intersecting the stacking direction A.

[0161] According to this configuration, an increase in the outer dimensions of the second member 662 due to the first protrusion 662g of the second member 662 can be suppressed or prevented by the recess 322e.

[0162] (Bus Bar 670 of Eighth Embodiment) (Configuration of Bus Bar 670 of Eighth Embodiment) The configuration of the bus bar 670 will be described with reference to FIG. 23 .

[0163] FIG. 23 is a top view showing a main part of a bus bar 670 according to the eighth embodiment.

[0164] The most protruding portion of the first protrusion 671g of the first member 671 corresponds to the center of the solid-state welded portion 320A. The first protrusion 671g is formed in a normal distribution shape along the vibration direction B. The first protrusion 671g is formed line-symmetrically with respect to an axis (the central axis of the solid-state welded portion 320A) that bisects the solid-state welded portion 320A in the width direction C. The most protruding portion of the second protrusion 672g of the second member 672 corresponds to the center of the solid-state welded portion 320A. The second protrusion 672g is formed in a normal distribution shape along the vibration direction B. The second protrusion 672g is formed line-symmetrically with respect to an axis (the central axis of the solid-state welded portion 320A) that bisects the solid-state welded portion 320A in the width direction C.

[0165] (Effects of Bus Bar 670 of Eighth Embodiment) The effects of the bus bar 670 will be described with reference to FIG.

[0166] (19) The most protruding portion of the first protrusion 671g of the first member 671 corresponds to the center of the solid-state welded portion 320A. The most protruding portion of the second protrusion 672g of the second member 672 corresponds to the center of the solid-state welded portion 320A. Only one of the first member 671 or the second member 672 may have the above configuration.

[0167] With this configuration, the first member 671 can be applied to a shape in which the most protruding portion of the first protrusion 671g of the first member 671 corresponds to the center of the solid-state welded portion 320A. The effect of the second protrusion 672g of the second member 672 is similar to the effect of the first protrusion 671g of the first member 671.

[0168] (Bus Bar 680 of Ninth Embodiment) (Configuration of Bus Bar 680 of Ninth Embodiment) The configuration of the bus bar 680 will be described with reference to FIG. 24 .

[0169] FIG. 24 is a top view showing a main part of a bus bar 680 according to the ninth embodiment.

[0170] The length of the recess 681e of the first member 681 along the first outer edge 681d is less than the length along the outer edge of the solid-state welded portion 320A. The entire region of the recess 681e along the first outer edge 681d faces the solid-state welded portion 320A in a direction intersecting the direction along the first outer edge 681d (width direction c). The recess 681e of the first member 681 is formed smaller along the first outer edge 681d than the solid-state welded portion 320A that faces the first outer edge 681d of the first member 681 in a direction intersecting the stacking direction A (width direction C). The recess 681e of the first member 681 being smaller than the solid-state welded portion 320A means that in the portion where the recess 681e and the solid-state welded portion 320A face each other in the width direction C, there is a region where the recess 681e does not exist but the solid-state welded portion 320A exists. The recess 681e is formed only in the first joint portion 321R among the first attachment portion 321P, the first bent portion 321Q, and the first joint portion 321R of the first member 681.

[0171] The length of the recess 682e of the second member 682 along the first outer edge 682d is less than the length along the outer edge of the solid-state welded portion 320A. The entire region of the recess 682e along the first outer edge 682d faces the solid-state welded portion 320A in a direction intersecting the direction along the first outer edge 682d (width direction c). The recess 682e of the second member 682 is formed smaller along the first outer edge 682d than the solid-state welded portion 320A that faces the first outer edge 682d of the second member 682 in a direction intersecting the stacking direction A (width direction C). The recess 682e of the second member 682 being smaller than the solid-state welded portion 320A means that in the portion where the recess 682e and the solid-state welded portion 320A face each other in the width direction C, there is a region where the recess 682e does not exist but the solid-state welded portion 320A exists. The recess 682e is formed only in the second joint portion 322R among the second attachment portion 322P, the second bent portion 322Q, and the second joint portion 322R of the second member 682.

[0172] (Effects of Bus Bar 680 of Ninth Embodiment) The effects of the bus bar 680 will be described with reference to FIG.

[0173] (15) The length of the recess 681e of the first member 681 along the first outer edge 681d is less than the length along the outer edge of the solid-state welded portion 320A. The entire region of the recess 681e along the first outer edge 681d faces the solid-state welded portion 320A in a direction intersecting the direction along the first outer edge 681d (width direction c). The length of the recess 682e of the second member 682 along the first outer edge 682d is less than the length along the outer edge of the solid-state welded portion 320A. The entire region of the recess 682e along the first outer edge 682d faces the solid-state welded portion 320A in a direction intersecting the direction along the first outer edge 682d (width direction c). Only one of the first member 681 or the second member 682 may have the above configuration.

[0174] According to this configuration, it is possible to relatively reduce the size of the recess 681e in the first member 681. The effect of the recess 682e in the second member 682 is similar to the effect of the recess 681e in the first member 681.

[0175] (Bus Bar 710 of Tenth Embodiment) (Configuration of Bus Bar 710 of Tenth Embodiment) The configuration of the bus bar 710 will be described with reference to FIGS. 25 and 26. FIG.

[0176] Fig. 25 is a top view showing a main part of a bus bar 710 according to the tenth embodiment. Fig. 26 is a bottom view showing the bus bar 710 of Fig. 25 .

[0177] The first member 711 corresponds to a configuration that does not include the second protruding portion 321h protruding from the second outer edge 321f. The other configuration of the first member 711 is similar to the configuration of the first member 321. The second member 712 corresponds to a configuration that does not include the second protruding portion 322h protruding from the second outer edge 322f. The other configuration of the second member 712 is similar to the configuration of the second member 322.

[0178] (Effects of Bus Bar 710 of Tenth Embodiment) The effects of the bus bar 710 will be described with reference to FIGS. 25 and 26. FIG.

[0179] (1) The first member 711 corresponds to a configuration that does not include the second protruding portion 321 h protruding from the second outer edge 321 f. The second member 712 corresponds to a configuration that does not include the second protruding portion 322 h protruding from the second outer edge 322 f.

[0180] According to this configuration, the bus bar 710 achieves some of the effects of the bus bar 320. The bus bar 710 has the effects related to the first protrusion.

[0181] (Bus Bar 720 of Eleventh Embodiment) (Configuration of Bus Bar 720 of Eleventh Embodiment) The configuration of the bus bar 720 will be described with reference to FIGS. 27 and 28. FIG.

[0182] Fig. 27 is a top view showing a main part of a bus bar 720 according to the eleventh embodiment. Fig. 28 is a bottom view showing a main part of the bus bar 720 of Fig. 27.

[0183] The first member 721 corresponds to a configuration that does not include the first protrusion 321g protruding from the recess 321e. The other configuration of the first member 721 is the same as the configuration of the first member 321. The second member 722 corresponds to a configuration that does not include the first protrusion 322g protruding from the recess 322e. The other configuration of the second member 722 is the same as the configuration of the second member 322.

[0184] (Effects of Bus Bar 720 of Eleventh Embodiment) The effects of the bus bar 720 will be described with reference to FIGS. 27 and 28. FIG.

[0185] The first member 721 corresponds to a configuration that does not include a first protrusion 321g protruding from the recess 321e. The first member 721 includes a second protrusion 321h protruding from a second outer edge 321f adjacent to the first outer edge 321d and exposed to the outside. The second member 722 corresponds to a configuration that does not include a first protrusion 322g protruding from the recess 322e. The second member 722 includes a second protrusion 322h protruding from a second outer edge 322f adjacent to the first outer edge 322d and exposed to the outside.

[0186] According to this configuration, the bus bar 720 achieves some of the effects of the bus bar 320. The bus bar 720 has the effect related to the second protrusion.

[0187] (Bus Bar 730 of Twelfth Embodiment) (Configuration of Bus Bar 730 of Twelfth Embodiment) The configuration of the bus bar 730 will be described with reference to FIGS. 29 and 30. FIG.

[0188] Fig. 29 is a perspective view showing a bus bar 730 of the twelfth embodiment from above. Fig. 30 is a perspective view showing the bus bar 730 of Fig. 29 from below.

[0189] The first member 731 and the second member 322 have different rigidities. The first member 731 and the second member 322 each include a recess. The recess of the first member 731 or the second member 322 with a relatively lower rigidity is relatively larger than the recess of the first member 731 or the second member 322 with a relatively higher rigidity. The first member 731 includes a recess 731e. The recess 731e of the first member 731 is relatively smaller than the recess 322e of the second member 322. The recess 731e has a shorter recess length in the width direction C than the recess 322e shown in FIG. 7 . The configuration of the first member 731 corresponds to a configuration in which the recess 321e of the first member 321 is relatively smaller. The first member 731 has a relatively higher rigidity than the second member 322. The recess 731 e included in the first member 731 is smaller than the recess 322 e included in the second member 322 .

[0190] (Effects of Bus Bar 730 of Twelfth Embodiment) The effects of the bus bar 730 will be described with reference to FIGS. 29 and 30. FIG.

[0191] (16) The first member 731 and the second member 322 have different rigidities. The first member 731 and the second member 322 each include a recess. The recess in the first member 731 or the second member 322 that has a relatively lower rigidity is larger than the recess in the first member 731 or the second member 322 that has a relatively higher rigidity.

[0192] With this configuration, the recess 322e can be made relatively large to accommodate the first protruding portion 322g, which has a relatively low rigidity and is prone to protrusion, and the recess 731e can be made relatively small to accommodate the first protruding portion 321g, which has a relatively high rigidity and is difficult to protrude. In this way, even when the recess 731e of the first member 731 is made relatively small, the most protruding portion of the first protruding portion 321g, which has a small protrusion amount, can be positioned approximately in the same position as the most protruding portion of the first protruding portion 322g. In other words, even when the recess 731e of the first member 731 is made relatively small, the influence of plastic deformation during solid-state welding on the outer dimensions can be effectively suppressed or prevented. Furthermore, since the size of the first member 731 does not need to be matched to the size of the second member 322, the first member 731 can be made relatively large, thereby improving heat dissipation and the rigidity of the busbar 730 as a whole.

[0193] (Bus Bar 740 of Thirteenth Embodiment) (Configuration of Bus Bar 740 of Thirteenth Embodiment) The configuration of the bus bar 740 will be described with reference to FIGS. 31 and 32. FIG.

[0194] Fig. 31 is a perspective view showing a bus bar 740 according to the thirteenth embodiment from above. Fig. 32 is a perspective view showing the bus bar 740 of Fig. 31 from below.

[0195] The bus bar 740 has a configuration in which the recess 741e of the bus bar 730 is formed over the entire outer edge 741k. That is, the entire outer edge 741k of the bus bar 740 is cut out to form the recess 741e.

[0196] (Effects of Bus Bar 740 of Thirteenth Embodiment) The effects of the bus bar 740 will be described with reference to FIGS. 31 and 32. FIG.

[0197] The bus bar 740 has a configuration in which the recess 741e of the bus bar 730 is formed over the entire outer edge 741k.

[0198] Such a configuration makes it possible to manufacture the bus bar 740 relatively easily.

[0199] (Bus Bar 750 of Fourteenth Embodiment) (Configuration of Bus Bar 750 of Fourteenth Embodiment) The configuration of the bus bar 750 will be described with reference to FIGS. 33 and 34. FIG.

[0200] Fig. 33 is a perspective view showing a bus bar 750 according to the fourteenth embodiment from above. Fig. 34 is a perspective view showing the bus bar 750 of Fig. 33 from below.

[0201] The first member 751 and the second member 322 have different rigidities. The recess 322e is included in the one having the relatively lower rigidity of the first member 751 and the second member 322. Of the first member 751 and the second member 322, only the second member 322 having the relatively lower rigidity includes the recess 322e. The first member 751 does not include a recess, a first protrusion, or the like. The rest of the configuration of the first member 751 is the same as the configuration of the first member 321.

[0202] (Effects of Bus Bar 750 of Fourteenth Embodiment) The effects of the bus bar 750 will be described with reference to FIGS. 33 and 34. FIG.

[0203] (17) The first member 751 and the second member 322 have different rigidities. The recess 322e is included in the member having the lower rigidity out of the first member 751 and the second member 322.

[0204] According to this configuration, recess 322e can be formed in second member 322 to match first protruding portion 322g, which has a relatively low rigidity and is prone to protruding. On the other hand, recess 322e is omitted in first member 751. This makes it relatively easy to manufacture bus bar 750.

[0205] (Bus Bar 760 of Fifteenth Embodiment) (Configuration of Bus Bar 760 of Fifteenth Embodiment) The configuration of the bus bar 760 will be described with reference to FIGS. 35 and 36. FIG.

[0206] Fig. 35 is a perspective view showing a bus bar 760 according to a fifteenth embodiment from above. Fig. 36 is a perspective view showing the bus bar 760 of Fig. 35 from below.

[0207] Of the first member 321 and the second member 762, only the first member 321, which has a relatively high rigidity, includes the recess 321 e. The second member 762 does not include a recess or a first protrusion, etc. The other configuration of the second member 762 is the same as the configuration of the second member 322.

[0208] (Effects of Bus Bar 760 of Fifteenth Embodiment) The effects of the bus bar 760 will be described with reference to FIGS. 35 and 36. FIG.

[0209] Of the first member 321 and the second member 762, the first member 321, which has a relatively higher rigidity, includes the recess 321e.

[0210] With this configuration, recess 321e can be formed in second member 762 to match first protrusion 321g, which has relatively high rigidity and is preferably prevented from interfering with other members. On the other hand, recess 321g is omitted in second member 762. This makes it relatively easy to manufacture bus bar 760.

[0211] (Bus Bar 770 of Sixteenth Embodiment) (Configuration of Bus Bar 770 of Sixteenth Embodiment) The configuration of the bus bar 770 will be described with reference to FIG.

[0212] FIG. 37 is a perspective view showing a bus bar 770 of the sixteenth embodiment from above.

[0213] When the protruding portion is included in the first member 321, the first protruding portion 321g protrudes from the outer edge of the first member 321 toward the second member 772 along the stacking direction A of the first member 321 and the second member 772. When the protruding portion is included in the second member 772, the first protruding portion 772g protrudes from the outer edge of the second member 772 toward the first member 321 along the stacking direction A of the first member 321 and the second member 772. A portion of the first protruding portion 772g of the second member 772 protrudes from the second member 772 toward the first member 321 in the stacking direction A. The first protruding portion 772g of the second member 772 covers a portion of the first protruding portion 321g of the first member 321.

[0214] (Effects of Bus Bar 770 of Sixteenth Embodiment) The effects of the bus bar 770 will be described with reference to FIG.

[0215] (18) When the protruding portion is included in the first member 321, the first protruding portion 321g protrudes from the outer edge of the first member 321 toward the second member 772 along the stacking direction A of the first member 321 and the second member 772. When the protruding portion is included in the second member 772, the first protruding portion 772g protrudes from the outer edge of the second member 772 toward the first member 321 along the stacking direction A of the first member 321 and the second member 772.

[0216] This configuration can be applied to a shape in which the first protruding portion 772g of the second member 322 protrudes from the second member 772 toward the first member 321, as in the bus bar 770. The first protruding portion 772g also deforms in the stacking direction A, thereby suppressing the amount of deformation (protrusion) in the width direction C. As a result, an increase in the external dimensions of the bus bar 770 can be effectively suppressed.

[0217] (Busbars and battery packs having the busbars of other embodiments) The busbars and battery packs of the present invention are not limited to the configurations of the busbars and battery packs described in the embodiments, and can be configured as appropriate based on the content described in the claims.

[0218] The busbars and battery packs of the embodiments are described in detail or simply to make the present invention easier to understand, and do not necessarily have to include all of the components described, or may include components not shown. Furthermore, some of the components of the embodiments may be deleted, replaced with components of other embodiments, or combined with components of other embodiments.

[0219] The number of batteries 100 included in the battery pack 1 is not limited to 20. The number of batteries 100 may be, for example, 2 to 19 or 21 or more. The batteries 100 are not limited to lithium-ion batteries. For example, nickel-metal hydride batteries and lead-acid batteries can be used as the batteries 100. The batteries 100 are not limited to secondary batteries. For example, primary batteries can be used as the batteries 100.

[0220] (Bus Bar 810 of Another Embodiment) (Configuration of Bus Bar 810) The configuration of the bus bar 810 will be described with reference to FIG.

[0221] FIG. 38 is a perspective view showing a main part of a bus bar 810 according to another embodiment.

[0222] The space portion of the first member 811 includes a through hole 811i formed in the first member 811. The first member 811 includes the through hole 811i instead of a recess. The through hole 811i is formed in a rectangular shape in the first member 811 between the outer edge 811e and the solid-state welded portion 320A. The through hole 811i is formed spaced apart from the outer edge 811e and the solid-state welded portion 320A in the width direction C of the first member 811. The through hole 811i may be formed so as to contact the solid-state welded portion 320A in the width direction C of the first member 811. The space portion of the second member 812 includes a through hole 812i formed in the second member 812. The second member 812 includes the through hole 812i instead of a recess. The through-hole 812i is formed in a rectangular shape in the second member 812 between the outer edge 812e and the solid-state welded portion 320A. The through-hole 812i is formed spaced apart from the outer edge 812e and the solid-state welded portion 320A in the width direction C of the second member 812. The through-hole 812i may be formed in the width direction C of the second member 812 so as to contact the solid-state welded portion 320A.

[0223] (Effects of Bus Bar 810) The effects of the bus bar 810 will be described with reference to FIG.

[0224] The space portion of the first member 811 includes a through-hole 811i formed in the first member 811. The space portion of the second member 812 includes a through-hole 812i formed in the second member 812. At least one of the first member 811 and the second member 812 may include a through-hole.

[0225] With this configuration, the first protrusion 321g can be provided in the through hole 811i without forming a recess in the first outer edge 321d of the first member 811. The effect of the through hole 812i in the second member 812 is similar to the effect of the through hole 811i in the first member 811. This allows, for example, the outer shapes of the first member 811 and the second member 812 to be rectangular when viewed from above, thereby reducing the number of corners in the outer shapes. Reducing the number of corners in the outer shapes reduces the risk of damage caused by interference between the corners and other components, such as cables.

[0226] DESCRIPTION OF SYMBOLS 1 Battery pack, 100 Battery, 101 Container, 102 Lid, 103 Positive electrode terminal, 104 Negative electrode terminal, 105 Safety valve, 200 Holding unit, 201 First end spacer, 202 Cell spacer, 203 Second end spacer, 211 First end block, 212 Second end block, 221 Insulating member, 222 Insert nut, 231 First side plate, 232 Second side plate, 241 Fastening bolt, 300 Bus bar unit, 310 First end bus bar (bus bar), 311 First member, 311i Insertion hole, 312 Second member, 320 Bus bar, 320A Solid-state welded portion, 321 First member, 321P First mounting portion, 321Q First bent portion, 321R First joint portion, 321a Mounting surface, 321b First boundary, 321c Second boundary, 321d First outer edge (outer edge), 321e Recessed portion, 321f Second outer edge, 321g First protrusion (protrusion), 321h Second protrusion, 322 Second member, 322P Second mounting portion, 322Q Second bent portion, 322R Second joint portion, 322a Mounting surface, 322b First boundary, 322c Second boundary, 322d First outer edge (outer edge), 322e Recessed portion, 322f Second outer edge, 322g First protrusion (protrusion), 322h Second protrusion, 330 Second end bus bar, 331 First part, 332 Second part, 332i Insertion hole, 340 busbar holder, 340a opening, 340b fixing portion, 340c holding portion, 340d insertion portion, 400 voltage detection unit, 401 voltage detection terminal, 402 electric wire, 500 temperature measurement unit, 501 temperature sensor, 502 electric wire, 610 busbar, 611 first member, 611P first mounting portion, 611Q first bent portion, 611R first joint portion, 611d first outer edge (outer edge), 611e recessed portion, 611e1 base end, 611e2 tip end, 611f second outer edge, 611g first protruding portion (protruding portion), 611h second protruding portion, 612 second member,612P Second mounting portion, 612Q Second bent portion, 612R Second joint portion, 612d First outer edge (outer edge), 612e Recessed portion, 612e1 Base end, 612e2 Tip end, 612f Second outer edge, 612g First protruding portion (protruding portion), 612h Second protruding portion, 620 Bus bar, 621 First member, 621e Recessed portion, 621f Second outer edge, 621g First protruding portion, 621h Second protruding portion, 622 Second member, 622e Recessed portion, 622f Second outer edge, 622g First protruding portion, 622h Second protruding portion, 630 Bus bar, 631 First member, 631m Recessed portion, 632 Second member, 632m Recess, 640 bus bar, 641 first member, 641d outer edge, 641e recess, 641e1 side surface, 641f second outer edge, 641g first protrusion, 642 second member, 642d outer edge, 642e recess, 642e1 side surface, 650 bus bar, 651 first member, 651e recess, 652 second member, 652e recess, 660 bus bar, 661 first member, 661g first protrusion, 662 second member, 662g first protrusion, 670 bus bar, 671 first member, 671g first protrusion, 672 second member, 672g second protrusion, 681 first member, 681d First outer edge (outer edge), 681e recessed portion, 682 second member, 682d first outer edge (outer edge), 682e recessed portion, 710 bus bar, 711 first member, 712 second member, 720 bus bar, 721 first member, 722 second member, 730 bus bar, 731 first member, 731e recessed portion, 740 bus bar, 741e recessed portion, 741k outer edge, 750 bus bar, 751 first member, 760 bus bar, 762 second member, 770 bus bar, 772 second member, 772g first protrusion, X stacking direction (of battery 100), Y width direction (of battery 100), Z height direction (of battery 100), A A: stacking direction (of the first member and the second member), B: vibration direction (of solid-state welding of the first member and the second member), C: width direction (of the first member and the second member),D1: center line (center) (of the solid-state welded portion 320A extending in the width direction C), D2: center line (center) (of the solid-state welded portion 320A extending in the vibration direction B).

Claims

1. A busbar comprising: a first member; and a second member laminated on the first member, wherein the first member and the second member include a solid-state welded portion formed by solid-state welding to each other, and at least one of the first member and the second member includes a concave recess exposed at an outer edge, and the recess is adjacent to the solid-state welded portion.

2. The busbar according to claim 1, wherein the recess is adjacent to the solid-state welded portion while being spaced apart from it.

3. The busbar according to claim 1, wherein at least one of the first member and the second member includes a protruding portion that protrudes outward from the recess.

4. The busbar according to claim 3, wherein a tip of the protrusion is located closer to the solid-state welded portion than the outer edge along a direction intersecting a stacking direction of the first member and the second member.

5. The busbar according to claim 3, wherein, when the recess is included in the first member, the protrusion is inclined toward the second member from the base end toward the tip end, and when the recess is included in the second member, the protrusion is inclined toward the first member from the base end toward the tip end.

6. The busbar according to claim 3, wherein the length of the recess along the outer edge is equal to or greater than the length of the solid-state welded portion along the outer edge, and the entire region of the recess along the outer edge faces the solid-state welded portion in a direction intersecting the direction along the outer edge.

7. The busbar according to claim 1, wherein the first member and the second member each include the recess.

8. The busbar according to claim 7, wherein each of the recesses at least partially overlaps with each other along the stacking direction of the first member and the second member.

9. The busbar according to claim 1, wherein at least one of the first member and the second member includes a second outer edge intersecting the outer edge and a second protruding portion protruding from the second outer edge, and when the second outer edge is included in the first member, the second protruding portion protrudes from the second outer edge of the first member toward the second member, and when the second outer edge is included in the second member, the second protruding portion protrudes from the second outer edge of the second member toward the first member.

10. The busbar according to claim 1, wherein, when the recess is included in the first member, the recess includes a portion formed so that its width in a direction intersecting with the outer edge is relatively narrower from the first member toward the second member, and when the recess is included in the second member, the recess includes a portion formed so that its width in a direction intersecting with the outer edge is relatively narrower from the second member toward the first member.

11. The busbar according to claim 1, wherein the recess includes a portion that is curved concavely toward the center of the solid-state welded portion.

12. The busbar according to claim 1, wherein at least one of the first member and the second member includes a second outer edge that intersects with the outer edge, and the recess and the second outer edge are adjacent to each other via a recess that is recessed toward the solid-state welded portion.

13. The busbar according to claim 1, wherein a side surface of the recess is inclined from the stacking direction of the first member and the second member toward the solid-state welded portion.

14. The busbar according to claim 3, wherein a tip of the protrusion protrudes outward beyond the outer edge in a direction intersecting the stacking direction of the first member and the second member.

15. The busbar according to claim 1, wherein the length of the recess along the outer edge is less than the length of the solid-state welded portion along the outer edge, and the entire region along the outer edge of the recess faces the solid-state welded portion in a direction intersecting the direction along the outer edge.

16. The busbar according to claim 1, wherein the first member and the second member have different rigidities, the first member and the second member each include the recess, and the recess in the first member or the second member having a relatively lower rigidity is relatively larger than the recess in the first member or the second member having a relatively higher rigidity.

17. The busbar according to claim 1, wherein the first member and the second member have different rigidities, and the recess is included in the first member or the second member that has a relatively lower rigidity.

18. The busbar according to claim 3, wherein, when the protruding portion is included in the first member, the protruding portion protrudes from the outer edge of the first member toward the second member along the stacking direction of the first member and the second member, and when the protruding portion is included in the second member, the protruding portion protrudes from the outer edge of the second member toward the first member along the stacking direction of the first member and the second member.

19. A battery pack comprising: a battery; and the bus bar according to claim 1 connected to the battery.

20. The battery pack according to claim 19, further comprising a holding member that contacts the outer edge and holds the bus bar.

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