Battery pack

Abstract

The present invention achieves a battery pack having a bus bar formed by favorably solid-phase bonding two or more members.　A bus bar 320 has a first member 321, and a second member 322, the hardness of which is lower than that of the first member 321. The first member 321 includes a first contact part 321R that is in contact with the second member 322 in the lamination direction A, and a non-contact part 321S that is continuous with the first contact part and not in contact with the second member. The second member includes a second contact part 322R that is in contact with the first contact part of the first member in the lamination direction. The first contact part and the second contact part include a solid-phase joint 320A. The non-contact part of the first member is located closer to a second attachment part 322P of the second member than the solid-phase joint. The leading edge 322e of the non-contact part of the first member is inclined in a direction crossing the lamination direction and is separated from the second contact part of the second member.

Description

battery pack

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

[0002] 2. Description of the Related Art Conventionally, a battery pack having a bus bar formed by solid-state welding of two or more members has been known (see, for example, Patent Document 1).

[0003] Special Publication No. 2012-515418

[0004] There is a demand for a bus bar formed by good solid-state welding of two or more members.

[0005] One embodiment of the battery pack includes a plurality of batteries and a bus bar connected to one of the batteries and another battery, or connected to one of the batteries and connected to an external electrical device. The bus bar includes a conductive first member and a conductive second member stacked and joined to the first member and having a lower hardness than the first member. The first member includes a first mounting portion attached to an electrode terminal of one of the batteries or to an electrical device, a first contact portion connected to the first mounting portion and in contact with the second member in the stacking direction, and a non-contact portion connected to the first contact portion and at least partially out of contact with the second member in the stacking direction. The second member includes a second mounting portion attached to an electrode terminal of another battery, and a second contact portion connected to the second mounting portion and in contact with the first contact portion of the first member in the stacking direction. The first contact portion of the first member and the second contact portion of the second member include a solid-state weld. For example, the first contact portion and the second contact portion include a solid-state welded portion that is solid-state welded toward a direction intersecting the stacking direction and including at least a side where the first non-contact portion of the first member and the second non-contact portion of the second member are located. The non-contact portion of the first member is located closer to the second attachment portion of the second member than the solid-state welded portion. The busbar includes at least one of the following configurations (1), (2), (3), (4), (5), and (6). In configuration (1), at least a tip of the non-contact portion of the first member is inclined with respect to a direction intersecting the stacking direction and spaced apart from the second contact portion of the second member. In configuration (2), the second member includes a bent portion between the second contact portion and the second attachment portion that is bent from the second contact portion toward the other end in the stacking direction. At least a tip of the non-contact portion of the first member is spaced apart from the bent portion of the second member. In the configuration (3), a tip of the non-contact portion of the first member includes a curved or inclined corner that faces the second member in the stacking direction, and a length of the corner of the first member along the stacking direction is 1 / 10 or more of a length of the non-contact portion of the first member along the stacking direction, or 0.1 mm or more.In the configuration (4), the second member includes an inclined portion between the second contact portion and the second mounting portion that is inclined from the second contact portion in a direction intersecting the stacking direction. At least a tip of the non-contact portion of the first member is spaced apart from the inclined portion of the second member. In the configuration (5), the second member includes a recess between the second contact portion and the second mounting portion that is recessed in a direction away from the non-contact portion of the first member with respect to the stacking direction. At least a tip of the non-contact portion of the first member is spaced apart from the recess of the second member. In the configuration (6), the non-contact portion of the first member is formed as a pair on both sides of the first contact portion of the first member. At least a tip of each of the pair of non-contact portions of the first member is spaced apart from the second member.

[0006] A battery pack according to a second embodiment of the present invention includes a plurality of batteries and a bus bar connected to one of the batteries and the other batteries, or connected to one of the batteries and connected to an external electrical device. The bus bar includes a conductive first member and a conductive second member made of the same material as the first member, stacked and joined to the first member. The first member includes a first mounting portion attached to an electrode terminal of one of the batteries or to an electrical device, a first contact portion connected to the first mounting portion and in contact with the second member in the stacking direction, and a first non-contact portion connected to the first contact portion and at least partially out of contact with the second member in the stacking direction. The second member includes a second mounting portion attached to an electrode terminal of the other battery, a second contact portion connected to the second mounting portion and in contact with the first contact portion of the first member in the stacking direction, and a second non-contact portion connected to the second contact portion and at least partially out of contact with the first contact portion of the first member in the stacking direction. For example, the first contact portion and the second contact portion include a solid-state welded portion that is solid-state welded toward a direction that intersects the stacking direction and includes at least a side on which the first non-contact portion of the first member and the second non-contact portion of the second member are located. The first contact portion of the first member and the second contact portion of the second member include a solid-state welded portion. The first non-contact portion of the first member is located closer to the second mounting portion of the second member than the solid-state welded portion. The second non-contact portion of the second member is located closer to the first mounting portion of the first member than the solid-state welded portion. The busbar includes at least one of the following configurations (1), (2), (3), (4), (5), and (6), and at least one of the following configurations (7), (8), and (9). In the configuration (1), at least a tip of the first non-contact portion of the first member is inclined with respect to a direction intersecting the stacking direction and is spaced apart from the second contact portion of the second member. In the configuration (2), the second member includes a second bent portion bent from the second contact portion along the stacking direction between the second contact portion and the second mounting portion.For example, the first member may further have the solid-state welded portion formed in a location that does not overlap with the first mounting portion in the stacking direction. At least a tip of the first non-contact portion of the first member is separated from the second bent portion of the second member. In the configuration (3), the tip of the first non-contact portion of the first member includes a curved or inclined corner that faces the second member in the stacking direction. The length of the corner of the first member along the stacking direction is 1 / 10 or more of the length of the first non-contact portion of the first member along the stacking direction, or 0.1 mm or more. In the configuration (4), the second member includes a second inclined portion between the second contact portion and the second mounting portion that is inclined from the second contact portion in a direction intersecting the stacking direction. At least a tip of the first non-contact portion of the first member is separated from the second inclined portion of the second member. In the configuration (5), the second member includes a recess between the second contact portion and the second mounting portion that is recessed in a direction away from the first non-contact portion of the first member with respect to the stacking direction. At least a tip of the first non-contact portion of the first member is spaced from the recess of the second member. In the configuration (6), the non-contact portion of the first member is formed as a pair on both sides of the first contact portion of the first member. At least a tip of the pair of non-contact portions of the first member is spaced from the second member. In the configuration (7), the tip of the second non-contact portion of the second member includes a curved or inclined corner that faces the first member in the stacking direction. The length of the corner of the second member along the stacking direction is 1 / 10 or more of the length of the second non-contact portion of the second member along the stacking direction, or 0.1 mm or more. In the configuration (8), at least a tip of the second non-contact portion of the second member is spaced from the first contact portion of the first member at an angle with respect to a direction intersecting the stacking direction. In the above configuration (9), the first member includes a recess between the first contact portion and the first attachment portion, recessed in a direction away from the second non-contact portion of the second member with respect to the stacking direction, and at least a tip of the second non-contact portion of the second member is away from the recess of the first member.

[0007] A third embodiment of the present invention provides a battery pack including a plurality of batteries and a bus bar connected to one of the batteries and the other batteries, or connected to one of the batteries and connected to an external electrical device. The bus bar includes a conductive first member and a conductive second member that is stacked and joined to the first member and has a hardness lower than that of the first member. The first member includes a first contact portion that contacts the second member in the stacking direction, and a non-contact portion that annularly connects to the first contact portion from outside the first contact portion on a plane intersecting the stacking direction and includes an annular portion that does not contact the second member in the stacking direction. The second member includes a second contact portion that contacts the first contact portion of the first member in the stacking direction. The non-contact portion of the first member annularly surrounds the second contact portion of the second member on a plane intersecting the stacking direction. The first contact portion of the first member and the second contact portion of the second member include a solid-state welded portion that is annularly solid-state welded along a plane that intersects the stacking direction and a region in which the non-contact portion of the first member is located.

[0008] A fourth embodiment of the present invention provides a bus bar for a battery assembly including a plurality of stacked batteries each having an electrode terminal, and a bus bar for connecting to an electrode terminal of a first battery, an electrode terminal of a second battery electrically connected to the first battery, or an external electrical device. The bus bar includes a first member having electrical conductivity, a second member having electrical conductivity, an overlapping portion where a portion of the first member and a portion of the second member overlap, and a solid-state welded portion formed in the overlapping portion. The first member includes a first mounting portion having a first mounting surface connected to either the first battery or the electrical device and a first back surface located opposite the first mounting surface, the first overlapping portion constituting the overlapping portion, and the solid-state welded portion formed in the first overlapping portion and positioned away from the first back surface. The second member has a second mounting portion having a second mounting surface connected to either the second battery or the electrical device when the first member is connected to the first battery, or to the first battery when the first member is connected to the electrical device, and a second back surface located opposite the second mounting surface, a second overlapping portion constituting the overlapping portion, and the solid-state welding portion formed in the second overlapping portion and positioned away from the second back surface. The first overlapping portion has a non-contact portion positioned away from the second overlapping portion in the overlapping direction of the first overlapping portion and the second overlapping portion, and a tip formed in the non-contact portion.

[0009] A battery pack having a bus bar formed by solid-state joining of two or more members can be obtained.

[0010] 1 is a perspective view showing a battery pack 1 of a first embodiment. A top view showing the battery pack 1 of FIG. 1 with a busbar holder 340 removed. 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. A perspective view showing the components of the batteries 100 and the holding unit 200 with a first side plate 231, a second side plate 232, and a fastening bolt 241 removed from FIG. 3 and exploded in the stacking direction X. A perspective view showing a busbar unit 300, a voltage detection unit 400, and a temperature measurement unit 500. A top view showing the busbar unit 300 and the voltage detection unit 400. A perspective view showing a busbar 320 of the first embodiment. A cross-sectional view showing the busbar 320 of the first embodiment. A schematic diagram showing solid-state welding of the busbar 320 of the first embodiment. 17 is a cross-sectional view schematically showing a state in which the first member 311 and the second member 322 of the bus bar 320 are solid-state welded by ultrasonic welding. A cross-sectional view showing the configuration of region 11 of FIG. 10. A cross-sectional view showing the configuration of region 12 of FIG. 11. A cross-sectional view showing another embodiment of the configuration of region 12 of FIG. 11. A cross-sectional view showing a solid-state welded state of the bus bar 320. A diagram showing the relationship between L / W and D / W defined for the bus bar 320. A diagram showing the relationship between D / W and T / W defined for the bus bar 320. A cross-sectional view schematically showing a state in which the first member 311 and the second member 322 of the bus bar 320 are solid-state welded by friction stirring. A cross-sectional view showing the configuration of region 18 of FIG. 17. A cross-sectional view showing a bus bar 610 according to Modification 1 of the first embodiment. A cross-sectional view showing a bus bar 620 according to Modification 2 of the first embodiment. A cross-sectional view showing a bus bar 630 according to Modification 3 of the first embodiment. A cross-sectional view showing a first member 631 of the bus bar 630. 1 is a cross-sectional view showing a bus bar 640 according to a fourth modification of the first embodiment; a cross-sectional view showing a bus bar 650 according to a fifth modification of the first embodiment; a cross-sectional view showing a bus bar 660 according to a sixth modification of the first embodiment; a cross-sectional view showing a bus bar 670 according to a seventh modification of the first embodiment; a cross-sectional view showing a bus bar 680 according to an eighth modification of the first embodiment; a cross-sectional view showing a bus bar 690 according to a ninth modification of the first embodiment; a perspective view showing a bus bar 710 according to the second embodiment; a cross-sectional view showing a bus bar 710 according to the second embodiment; a cross-sectional view showing a bus bar 720 according to a first modification of the second embodiment; a cross-sectional view showing a bus bar 730 according to a second modification of the second embodiment; a cross-sectional view showing a bus bar 740 according to a third modification of the second embodiment; a cross-sectional view showing a bus bar 750 according to a fourth modification of the second embodiment.1 is a cross-sectional view showing a busbar 760 according to a fifth modification of the second embodiment; a cross-sectional view showing a busbar 810 according to the third embodiment; a cross-sectional view partially showing the busbar 810 according to the third embodiment; a cross-sectional view partially showing the busbar 820 according to a first modification of the third embodiment; a cross-sectional view partially showing the busbar 830 according to a second modification of the third embodiment; a cross-sectional view partially showing the busbar 840 according to a third modification of the third embodiment; a cross-sectional view partially showing the busbar 850 according to a fourth modification of the third embodiment; a cross-sectional view partially showing the busbar 860 according to a fifth modification of the third embodiment; a cross-sectional view partially showing the busbar 870 according to a sixth modification of the third embodiment; a cross-sectional view partially showing the busbar 880 according to a seventh modification of the third embodiment; a cross-sectional view partially showing the busbar 910 according to the fourth embodiment; a perspective view partially showing the busbar 1010 according to the fifth embodiment; a cross-sectional view partially showing the busbar 1010 according to the fifth embodiment; a schematic view partially showing the solid-state welding of the busbar 1010 according to the fifth embodiment; a perspective view partially showing the busbar 1110 according to the sixth embodiment. FIG. 11 is a cross-sectional view showing a bus bar 1110 according to a sixth embodiment.

[0011] 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. When the shape and length of a first member and the shape and length of a second member are different in size or length, the shape and length of the first member may be exaggerated to show differences. In each drawing, the same components are denoted by the same reference numerals. 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 so that the top and bottom surfaces are reversed, or if the battery pack 1 is rotated 90 degrees so that the top surface is positioned as a side, the stacking direction X, width direction Y, and height direction Z of the battery pack 1 will change. The stacking direction A of the first member 321 etc. and the second member 322 etc., the direction B along the contact surface 321d or the contact surface 322d having the solid-state welded portion of the first member 321 etc. and the second member 322 etc., and the direction C perpendicular to the direction B are indicated by arrows. The direction B indicated by the arrow is an example and is intended to facilitate understanding of the embodiment corresponding to the invention. In each drawing, the threads on the outer peripheral surface of the fastening bolt and the grooves on the inner peripheral surface of the insert nut are not shown. For example, the direction B is the vibration direction in the solid-state welding.

[0012] (General Configuration Provided in Battery Pack 1 of First Embodiment) A general configuration provided in the battery pack 1 of the first embodiment will be described with reference to FIGS. 1 to 6. FIG.

[0013] FIG. 1 is a perspective view showing a battery pack 1 of the first embodiment. FIG. 2 is a top view of the battery pack 1 of FIG. 1 , with a busbar holder 340 removed. 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 a first side plate 231, a second side plate 232, and fastening bolts 241 removed from FIG. 3 . FIG. 5 is a perspective view showing a busbar unit 300, a voltage detection unit 400, and a temperature measurement unit 500. FIG. 6 is a top view showing the busbar unit 300 and the voltage detection unit 400.

[0014] 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.

[0015] 1, the battery pack 1 includes a plurality of batteries 100, a holding unit 200 that holds the plurality of batteries 100, and a bus bar 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.

[0016] (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.

[0017] 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 .

[0018] 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.

[0019] (Configuration of holding unit 200) As shown in Figures 1 to 4, the holding unit 200 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] (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.

[0032] 5 and 6 , 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.

[0033] 5 and 6, the electric wire 402 is joined to the voltage detection terminal 401. The electric wire 402 electrically connects the voltage detection terminal 401 to an external control device.

[0034] (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.

[0035] 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.

[0036] 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.

[0037] (Configuration of Busbar Unit 300 Provided in Battery Pack 1 of First Embodiment) The configuration of the busbar unit 300 provided in the battery pack 1 of the first embodiment will be described with reference to FIGS. 1, 2, and 5 to 18. FIG.

[0038] The busbar unit 300 shown in Figures 1, 2, and 5 to 18 electrically connects a plurality of batteries 100. As shown in Figure 5, the busbar unit 300 includes a first end busbar 310, a plurality of busbars 320, a second end busbar 330, and a busbar holder 340. The components included in the busbar unit 300 will be described below.

[0039] (Configuration of First End Bus Bar 310) The configuration of the first end bus bar 310 will be described with reference to Figs. 2, 5 and 6. Figs.

[0040] The first end bus bar 310 is connected to one battery 100 and also to an external electrical device. As shown in FIG. 2 , 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 among the 20 stacked batteries 100. The first end bus bar 310 corresponds to the bus bar of configuration (1). As shown in FIGS. 5 and 6 , the first end bus bar 310 has a first member 311 and a second member 312.

[0041] In the first end bus bar 310, the first member 311 is an electrical device to which a bus bar electrically connected to an external control device is joined. 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. The first member 311 has an insertion hole 311i formed therein. A fastening bolt is inserted into the insertion hole 311i. The first member 311 and the bus bar electrically connected to the external control device are joined by the fastening bolt. The other configuration of the first member 311 is the same as the configuration of the first member 321 of the bus bar 320, which will be described later. The second member 312 is joined to the positive terminal 103 of the battery 100. The other configuration of the second member 312 is the same as the configuration of the second member 322 of the bus bar 320, which will be described later.

[0042] (Configuration of Bus Bar 320) The configuration of the bus bar 320 will be described with reference to Figs. 7 and 8 .

[0043] Fig. 7 is a perspective view showing the bus bar 320 of the first embodiment. Fig. 8 is a cross-sectional view showing the bus bar 320 of the first embodiment.

[0044] The bus bar 320 is connected to one battery 100 and another battery 100. As shown in Fig. 2 , the bus bar 320 electrically connects the 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 the 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 of the batteries 100.

[0045] The bus bar 320 corresponds to the bus bar of configuration (1). As shown in FIGS. 7 and 8 , the bus bar 320 has a first member 321 and a second member 322. In FIGS. 7 and 8 , the stacking direction A of the first member 321 and the second member 322, the direction B in solid-state welding of the first member 321 and the second member 322, and the direction C perpendicular to the direction B are indicated by arrows. The vibration direction B is perpendicular to the stacking direction A. The direction C perpendicular to the vibration direction B is perpendicular to the stacking direction A. For example, the direction B is perpendicular to the direction A. Alternatively, the direction B is a desired direction along the contact surface 321d or the contact surface 322d having the solid-state welded portion. Alternatively, the direction B is the vibration direction in solid-state welding.

[0046] For example, one battery 100 having a negative electrode terminal 104 containing copper and another battery 100 having a positive electrode terminal 103 containing aluminum are electrically joined by the bus bar 320. For this purpose, the bus bar 320 is formed by solid-state joining, for example, a first member 321 containing copper and a second member 322 containing aluminum.

[0047] 7 and 8, the first member 321 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 321S. The first member 321 is integrally formed with the first attachment portion 321P, the first bent portion 321Q, the first contact portion 321R, and the non-contact portion 321S in this order.

[0048] 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 direction B and direction C perpendicular to direction B, and is attached to the negative electrode terminal 104. The first mounting portion 321P extends along direction B. For example, direction B is a direction perpendicular to direction A. Alternatively, direction B is a desired direction along the contact surface 321d or contact surface 322d having the solid-state welding portion. Alternatively, direction B is the vibration direction during solid-state welding. 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 attachment portion 321P may be curved or cut out in a straight line. The first attachment portion 321P is joined to the negative electrode terminal 104 by, for example, laser welding.

[0049] As shown in FIGS. 7 and 8 , the first bent portion 321Q (bent portion) is bent along the stacking direction A between the first contact portion 321R and the first attachment portion 321P. The first bent portion 321Q is perpendicular to the first attachment portion 321P and the first contact 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 attachment portion 321P is formed in an arc shape. A second boundary 321c at the boundary between the first bent portion 321Q and the first contact portion 321R is formed in an arc shape.

[0050] 7 and 8 , the first bent portion 321Q is bent from one end to the other end in the stacking direction A between the first contact portion 321R and the first attachment portion 321P. This configuration relates to configuration (2) of the busbar 320 of one embodiment. 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 contact portion 321R. The one end of the first bent portion 321Q may be connected to the first contact portion 321R. The other end of the first bent portion 321Q may be connected to the first attachment portion 321P. The shape of the first bending portion 321Q bending from one end to the other end in the stacking direction A is a shape that does not bend from one end to the other end in the stacking direction A and then fold back from the other end in the stacking direction A to the one end. That is, the overall shape of the first bending portion 321Q is not configured as a U-shape or the like. A U-shape corresponds to a shape that bends from one end to the other end in the stacking direction A and then folds back from the other end to the one end in the stacking direction A. A portion of the overall shape of the first bending portion 321Q may be configured as a U-shape or the like. That is, a portion of the region extending from one end to the other end of the first bending portion 321Q may include a U-shape or the like. One end of the first bending portion 321Q and the other end of the first bending portion 321Q are not at the same position or relatively close to each other along the stacking direction A.

[0051] 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 electrode terminal 104 of the battery 100. The first bent portion 321Q also reduces the spring constant of the bus bar 320. Specifically, the first bent portion 321Q relieves stress on the bus bar 320 caused by expansion and contraction of the battery 100 and vibration of the battery pack 1. 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 second bent portion 322Q.

[0052] 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.

[0053] As shown in FIGS. 7 and 8 , the first contact portion 321R is connected to the first bent portion 321Q. The first contact portion 321R is in contact with the second member 322 in the stacking direction A. As shown in FIG. 7 , the first contact portion 321R is formed in a plate shape. When direction B is the vibration direction, the first contact portion 321R has a contact surface 321d formed by the vibration direction B and a direction C perpendicular to the vibration direction B, which contacts the second member 322. The first contact portion 321R extends along the vibration direction B. The first contact portion 321R does not face the first mounting portion 321P along the stacking direction A. The first contact portion 321R extends in a direction away from the first mounting portion 321P along the vibration direction B via the first bent portion 321Q. The first contact portion 321R is formed parallel to the first mounting portion 321P.

[0054] As shown in FIGS. 7 and 8 , the non-contact portion 321S is continuous with the first contact portion 321R. The non-contact portion 321S is inclined with respect to a direction intersecting the stacking direction A (vibration direction B). For example, the non-contact portion 321S is inclined with respect to a direction along the contact surface 321d having the solid-state welded portion (vibration direction B). Alternatively, the non-contact portion 321S is inclined with respect to a direction intersecting the stacking direction A (vibration direction B). The non-contact portion 321S is inclined toward the side away from the battery 100. The inclination angle of the non-contact portion 321S is, for example, 0.01 degrees or more and 120 degrees or less. The inclination angle of the non-contact portion 321S is preferably 0.01 degrees or more and 90 degrees or less, and more preferably 0.01 degrees or more and 60 degrees or less. The angle of inclination of the non-contact portion 321S is preferably larger than the angle at which a separation of 0.01 mm or more occurs between the non-contact portion 321S and the second member 322 along the stacking direction A.

[0055] The non-contact portion 321S is not in contact with the second member 322 in the stacking direction A. A tip 321e of the non-contact portion 321S is spaced apart from the second contact portion 322R of the second member 322. The non-contact portion 321S is spaced apart from the second contact portion 322R of the second member 322. The non-contact portion 321S is located in a region relatively closer to the second contact portion 322R than the second mounting portion 322P of the second member 322 in a direction B intersecting the stacking direction A, for example, the vibration direction. The tip 321e of the non-contact portion 321S is located in a region relatively closer to the second contact portion 322R than the second bent portion 322Q of the second member 322. There is no region of the non-contact portion 321S that faces the second member 322 along direction B orthogonal to the stacking direction A, for example, along the vibration direction.

[0056] 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.

[0057] The first member 321 is electrically conductive. The first member 321 has a higher hardness than the second member 322. The first member 321 includes, 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.

[0058] 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.

[0059] 7 and 8, the second member 322 includes a second mounting portion 322P, a second bent portion 322Q, and a second contact portion 322R. The second member 322 is integrally formed with the second mounting portion 322P, the second bent portion 322Q, and the second contact portion 322R in this order.

[0060] 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 attached to the positive electrode terminal 103 and is defined by a direction B along the contact surface 321d or 322d having the solid-state welded portion and a direction C perpendicular to direction B. The second mounting portion 322P extends along direction B. For example, direction B may be a desired direction along the contact surface 321d or 322d having the solid-state welded portion. Alternatively, direction B may be a vibration direction. The second mounting portion 322P may have a through hole. For example, a test 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 attachment portion 322P may be curved or cut out in a straight line. The second attachment portion 322P is joined to the positive electrode terminal 103 by, for example, laser welding.

[0061] As shown in Figures 7 and 8, the second bent portion 322Q (bent portion) is bent along the stacking direction A between the second contact portion 322R and the second attachment portion 322P. The second bent portion 322Q is perpendicular to the second attachment portion 322P and the second contact portion 322R. As shown in Figure 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 attachment portion 322P is formed in an arc shape. A second boundary 322c at the boundary between the second bent portion 322Q and the second contact portion 322R is formed in an arc shape.

[0062] As shown in FIGS. 7 and 8 , the second bent portion 322Q is bent from one end to the other end in the stacking direction A between the second contact portion 322R and the second attachment portion 322P. This configuration is related to configuration (2) of the busbar 320 of one embodiment. 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 contact portion 322R. The shape of the second bent portion 322Q, which is bent from one end to the other end in the stacking direction A, is such that the second bent portion 322Q is bent from one end to the other end in the stacking direction A and then does not fold back from the other end 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 an overall shape that is bent from one end side to the other end side in the stacking direction A and then folded back from the other end side to the one end side in the stacking direction A. A part of the overall shape of the second bending portion 322Q may be configured with a U-shape or the like. That is, a part of the region extending from one end side to the other end side of the second bending portion 322Q may include a U-shape or the like. One end side of the second bending portion 322Q and the other end side of the second bending portion 322Q are not at the same position or relatively close positions along the stacking direction A.

[0063] 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 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 caused by 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.

[0064] 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.

[0065] As shown in FIGS. 7 and 8 , the second contact portion 322R is connected to the second bent portion 322Q. The second contact portion 322R is in contact with the first member 321 in the stacking direction A. As shown in FIG. 7 , the second contact portion 322R is formed in a plate shape. The second contact portion 322R has a contact surface 322d that is formed by direction B along the contact surface 321d or 322d having the solid-state welded portion and direction C perpendicular to direction B, and is in contact with the first member 321. The second contact portion 322R extends along direction B. The second contact portion 322R does not face the second mounting portion 322P along the stacking direction A. The second contact portion 322R extends in direction B away from the second mounting portion 322P via the second bent portion 322Q. The second contact portion 322R is formed parallel to the second mounting portion 322P. For example, direction B is the vibration direction.

[0066] 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.

[0067] The second member 322 is electrically conductive. 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.

[0068] 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.

[0069] (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.

[0070] In the bus bar 320, the first contact portion 321R of the first member 321 and the second contact portion 322R of the second member 322 are solid-state welded to form a solid-state welded portion 320A. The bus bar 320 is solid-state welded at the boundary between the contact surface 321d of the first contact portion 321R of the first member 321 and the contact surface 322d of the second contact portion 322R of the second member 322. The first contact portion 321R of the first member 321 and the second contact portion 322R of the second member 322 are solid-state welded in a vibration direction B (e.g., a vibration direction) perpendicular to the stacking direction A toward the side where the non-contact portion 321S of the first member 321 is located. The non-contact portion 321S of the first member 321 is located closer to the second mounting portion 322P of the second member 322 than the solid-state welded portion 320A.

[0071] 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. For example, when direction B is the vibration direction, the longitudinal direction of the solid-state welded portion 320A is a direction along direction C intersecting with vibration direction B. The lateral direction of the solid-state welded portion 320A is a direction along vibration direction B. That is, as shown in FIG. 7 , the length of the rectangular solid-state welded portion 320A along direction C intersecting with vibration direction B is longer than the length along the direction B. The longitudinal direction of the solid-state welded portion 320A may be a direction along vibration direction B, and the lateral direction may be a direction along direction C intersecting with 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 direction C intersecting with vibration direction B. The solid-state welded portion 320A may also be a square shape. 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 direction C that intersects with the vibration direction B.

[0072] 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.

[0073] (Solid-State Joining of Bus Bar 320 by Ultrasonic Welding) Solid-state joining of bus bar 320 by ultrasonic welding will be described with reference to FIGS. 9 to 12. FIG.

[0074] Fig. 9 is a schematic diagram showing solid-state welding of the bus bar 320 according to the first embodiment. Fig. 10 is a cross-sectional view showing a state in which the first member 311 and the second member 322 of the bus bar 320 are solid-state welded by ultrasonic waves. Fig. 11 is a cross-sectional view showing the configuration of region 11 in Fig. 10. Fig. 12 is a cross-sectional view showing the configuration of region 12 in Fig. 11.

[0075] When the first member 321 and the second member 322 are pressed against the stacking direction A and the direction B is set as the vibration direction, the solid-state welded portion 320A of the busbar 320 is formed by applying ultrasonic vibrations W1 in the vibration direction B. In solid-state welding by ultrasonic welding, for example, pressure is applied from the side of the first member 321. In this case, the horn 11 is brought into contact with the first member 321, and the anvil 12 is brought into contact with the second member 322. In solid-state welding by ultrasonic welding, pressure may also be applied from the side of the second member 322. In this case, the anvil 12 is brought into contact with the first member 321, and the horn 11 is brought into contact with the second member 322.

[0076] The solid-state welded portion 320A is formed by applying a vibration W1 linearly within a plane of a vibration direction B while the first member 321 and the second member 322 are pressed against each other in the stacking direction A. The horn 11 is vibrated along the vibration direction B. The horn 11 may also be vibrated along a direction intersecting the vibration direction B.

[0077] In solid-state joining by ultrasonic welding, the horn 11 applies ultrasonic vibrations W1 to the first and second members. The anvil 12 is disposed opposite the horn 11 via the first and second members and receives the vibrations W1 of the horn 11. The vibrations W1 of the horn 11 may induce vibrations W1 of the anvil 12 via the first and second members 321 and 322. The solid-state welded portion 320A is formed as an indentation in the first and second members 321 and 322 by ultrasonic welding or the like.

[0078] As shown in FIGS. 10 to 12 , the first contact portion 321R of the first member 321 has a plurality of indentations 321t formed by transferring the shapes of the plurality of protrusions formed on the horn 11. For example, the plurality of indentations 321t are formed in a matrix pattern on the first member 321. If the horn 11 has a plurality of protrusions, each of which is shaped like a quadrangular pyramid, then the first contact portion 321R of the first member 321 has a plurality of recesses, each of which is shaped like a quadrangular pyramid. These recesses correspond to the indentations 321t formed on the first contact portion 321R. The indentations 321t on the first contact portion 321R are formed by the pressure P1 applied by the horn 11 and the ultrasonic vibration W1 generated by the horn 11. The indentations 321t are, for example, recesses shaped like quadrangular pyramids, but the shape is not limited thereto. 11 and 12 , in the first contact portion 321R, a non-indentation portion 321v exists between adjacent indentations 321t. The non-indentation portion 321v is not essential. The first contact portion 321R of the first member 321 has a non-bonding region 321w that is in contact with the second contact portion 322R of the second member 322 but is not bonded to the second contact portion 322R of the second member 322. The non-bonding region 321w of the first contact portion 321R is continuous with the non-bonding region 321z of the non-contact portion 321S along the vibration direction B of the ultrasonic bonding.

[0079] The second contact portion 322R of the second member 322 has a plurality of indentations 322t formed thereon, for example, by transferring the shapes of the plurality of protrusions formed on the anvil 12. For example, the plurality of indentations 322t are formed in a matrix pattern on the second member 322. When the anvil 12 has a plurality of pyramidal protrusions, the second contact portion 322R of the second member 322 has a plurality of pyramidal recesses formed thereon. These recesses correspond to the indentations 322t formed on the second contact portion 322R. The indentations 322t on the second contact portion 322R are formed by the application of pressure P2 by the anvil 12, pressure P1 by the horn 11, and ultrasonic vibration W1. The application of pressure P2 by the anvil 12 may be merely a reaction force to the application of pressure P1 by the horn 11. The indentations 322t are, for example, pyramidal recesses, but the shape is not limited thereto. 11 , in the second contact portion 322R, a non-indentation portion 322v exists between adjacent indentations 322t. The non-indentation portion 322v is not essential. The second contact portion 322R of the second member 322 has a second non-bonded portion 322w that is in contact with the first contact portion 321R of the first member 321 but is not bonded to the first contact portion 321R of the first member 321. The second non-bonded portion 322w of the second contact portion 322R is continuous with the non-bonded region 322z of the second member 322 along the vibration direction B of the ultrasonic bonding.

[0080] 12 , the non-contact portion 321S of the first member 321 is spaced apart from the second member 322. The distance in the stacking direction A between the non-contact portion 321S and the second member 322 increases toward the tip 321e of the non-contact portion 321S. A first distance d1 in the stacking direction A between the tip 321e of the non-contact portion 321S and the second member 322 is longer than a second distance d2 in the stacking direction A between the portion of the non-contact portion 321S excluding the tip 321e and the second member 322.

[0081] (Another Form of Solid-State Welding by Ultrasonic Welding of Bus Bar 320) Another form of solid-state welding by ultrasonic welding of bus bar 320 will be described with reference to FIG.

[0082] FIG. 13 is a cross-sectional view showing another configuration of the region 12 in FIG.

[0083] In solid-state welding of the bus bar 320 by ultrasonic welding, a configuration such as that shown in FIG. 13 may be obtained.

[0084] 13, the non-contact portion 321S of the first member 321 is spaced apart from the second member 322. The non-bonding region 321w of the first contact portion 321R of the first member 321 is also spaced apart from the second member 322.

[0085] The first contact portion 321R includes a non-bonding region 321w. The non-bonding region 321w is located at both ends of the first contact portion 321R along the vibration direction B. The non-bonding region 321w may be located at only one end of the first contact portion 321R along the vibration direction B. The non-bonding region 321w of the first contact portion 321R is separated from the second member 322 because the outer shape of the first contact portion 321R of the first member 321 is plastically deformed when the first member 321 and the second member 322 are solid-state bonded by ultrasonic bonding. The plastic deformation of the outer shape of the first contact portion 321R occurs due to pressure applied by the horn and ultrasonic vibration. Of the plastic deformation of the outer shape of the first contact portion 321R, the plastic deformation in the non-bonding region 321w is a bending deformation in the stacking direction A such that the first member 321 is separated from the second member 322. That is, during solid-state joining by ultrasonic joining, the non-joining regions 321w located at both ends of the first contact portion 321R along the vibration direction B may be distorted so as to move away from the second member 322 along the stacking direction A.

[0086] When the first member 321 and the second member 322 are solid-state joined by ultrasonic bonding, the non-contact portion 321S of the first member 321 becomes further separated from the second member 322 as the non-bonding region 321w of the first contact portion 321R moves away from the second member 322.

[0087] The degree of plastic deformation of the outer shape of the first member 321 depends on the ultrasonic bonding conditions. The ultrasonic bonding conditions are, for example, the conditions of the ultrasonic waves applied to the first member 321. The ultrasonic bonding conditions are also conditions related to the relative positional relationship along the stacking direction A of the horn, the anvil, the first member 321, and the second member 322. Depending on the ultrasonic bonding conditions, the outer shape of the first member 321 may be plastically deformed, and the outer shape of the second member 322 may also be plastically deformed.

[0088] The distance between the first member 321 and the second member 322 in the stacking direction A increases toward the tip 321e of the non-contact portion 321S. A first distance d3 in the stacking direction A between the tip 321e of the non-contact portion 321S and the second member 322 is longer than a second distance d4 in the stacking direction A between the portion of the non-contact portion 321S excluding the tip 321e and the second member 322. The first distance d3 and the second distance d4 are longer than a second distance d5 in the stacking direction A between the non-bonded region 321w of the first contact portion 321R of the first member 321 and the second member 322.

[0089] In the first member 321, the non-contact portion 321S connected to the first contact portion 321R may be distorted relatively more away from the second member 322 along the stacking direction A than the first bent portion 321Q connected to the first contact portion 321R.

[0090] (Experimental Results of Ultrasonic Welding of Bus Bar 320) Experimental results of solid-state welding of bus bar 320 will be described with reference to FIGS. 14 to 16. FIG.

[0091] Fig. 14 is a cross-sectional view showing a solid-state welded state of bus bar 320. Fig. 15 is a diagram showing the relationship between L / W and D / W defined for bus bar 320. Fig. 16 is a diagram showing the relationship between D / W and T / W defined for bus bar 320.

[0092] First, the relationship between L / W and D / W defined for the bus bar 320 will be described with reference to FIGS. 14 and 15. FIG.

[0093] While the first member 321 and the second member 322 are pressed by the horn 11 and the anvil 12, ultrasonic waves are applied to the first member 321 by the horn 11. As shown in FIG. 14 , the application of ultrasonic waves may cause the non-contact portion 321S of the first member 321 to deform in a direction V away from the second member 322. Here, the distance along the stacking direction A from the boundary between the contact surface 321d of the first contact portion 321R and the contact surface 322d of the second contact portion 322R to the tip 321e of the non-contact portion 321S is defined as a first distance L. For example, if the vibration direction is set to direction B, the distance along the vibration direction B between the tip 321e of the non-contact portion 321S and the side end of the horn 11 is defined as a second distance D. The distance from the center of the first bent portion 321Q of the first member 321 to the end of the first contact portion 321R is defined as a third distance W. The thickness of the first member 321 along the stacking direction A and the thickness of the second member 322 along the stacking direction A are defined as plate thicknesses T. FIG. 15 shows the relationship between the first distance L and the second distance D when the plate thickness T is 0.07×W, 0.11×W, and 0.14×W. The vertical axis of FIG. 15 represents L / W, which is the first distance L divided by the third distance W. The horizontal axis of FIG. 15 represents D / W, which is the second distance D divided by the third distance W. When the first distance L is equal to or less than 0, the tip 321e of the non-contact portion 321S contacts or collides with the second member 322. As shown in FIG. 15, the thinner the plate thickness T of the first member 321 and the second member 322, the easier they are to deform. As shown in FIG. 15, when the L / W distance is equal to or greater than 0, the D / W distance decreases.

[0094] Next, the relationship between D / W and T / W defined for the bus bar 320 will be described with reference to FIGS. 14 and 16. FIG.

[0095] The vertical axis of FIG. 16 represents D / W, which is the second distance D divided by the third distance W. The horizontal axis of FIG. 16 represents T / W, which is the plate thickness T divided by the third distance W. As shown in FIG. 16, when T / W is increased, the D / W distance at which the L / W distance becomes 0 tends to saturate. As shown in FIG. 16, when T / W is greater than 0.1, L / W becomes greater than 0 by making D / W at least 0.04. From the perspective of a safety factor, D / W may be greater than 0.04. Since the bus bar 320 becomes longer as the second distance D increases, it is preferable to shorten the second distance D. When T / W is greater than 0.1, the value of D / W is set to 0.04 or more and 10 or less. When T / W is greater than 0.1, the value of D / W is preferably set to 0.04 or more and 5 or less, and more preferably 0.04 or more and 1 or less. On the other hand, when the plate thickness T is less than 0.1, D / W can be set to 0.04 or less. As a result of calculating the relational expression, the relationship between the second distance D and the plate thickness T is expressed by the formula: second distance D ≈ 0.38 × plate thickness T when T / W is 0.1 or less. Therefore, when T / W is 0.1 or less, for example, D / W is set to 0.38 × T / W or more and 10 mm or less. When T / W is 0.1 or less, it is preferable to set D / W to 0.38 × T / W or more and 5 mm or less, and more preferably to set D / W to 0.38 × T / W or more and 1 mm or less. As an example, the third distance W was calculated to be 5.5 mm, but the value of W is not limited to this and can be set freely depending on the shape. The plate thickness T of the first member 321 and the plate thickness T of the second member 322 are set to be the same. The deformation of the non-contact portion 321S of the first member 321 mainly depends on the plate thickness T of the first member 321 with which the horn 11 contacts. Since the second member 322 does not come into contact with the horn 11, the thickness T of the second member 322 may be changed.

[0096] (Configuration of Second End Bus Bar 330) The configuration of the second end bus bar 330 will be described with reference to Figs. 2, 5 and 6. Figs.

[0097] The second end bus bar 330 is connected to one battery 100 and also to an external electrical device. As shown in Fig. 2 , the second end bus bar 330 is joined to the negative terminal 104 of the battery 100 that is closest to the second end block 212 among the 20 stacked batteries 100. As shown in Figs. 5 and 6 , the second end bus bar 330 has a first portion 331 and a second portion 332.

[0098] 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 to which a bus bar that is electrically connected to an external control device is joined. 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 and the bus bar that is electrically connected to the external control device are joined by the fastening bolt. The second portion 332 is formed integrally with the first portion 331. The second end bus bar 330 is made of, for example, copper.

[0099] As shown in FIG. 1 , the busbar holder 340 integrally holds the first end busbar 310, the plurality of busbars 320, and the second end busbar 330. The busbar holder 340 also covers and insulates the stacked batteries 100. As shown in FIG. 5 , the busbar holder 340 is formed in a plate shape. A plurality of openings 340a are formed in the busbar holder 340. Each opening 340a exposes the first joint portion or the second joint portion of the first end busbar 310, the plurality of busbars 320, and the second end busbar 330 toward the battery 100. Each opening 340a is larger than the first joint portion or the second joint portion of the corresponding busbar. A plurality of holding portions 340b are formed in the busbar holder 340. Each holding portion 340b holds an end of the first joint portion or the second joint portion of the first end bus bar 310, the plurality of bus bars 320, and the second end bus bar 330. Each holding portion 340b is formed on the edge of the opening 340a. Each holding portion 340b has a linear groove along the surface of the bus bar holder 340. An end of the first joint portion or the second joint portion of the corresponding bus bar is inserted into the groove provided in each holding portion 340b. The bus bar holder 340 is formed with a plurality of insertion portions 340c. Electric wires 502 of the temperature measurement unit 500 are inserted into the insertion portions 340c.

[0100] (Configuration of Solid-State Welding by Friction Stirring of Bus Bar 320) The configuration of solid-state welding by friction stir welding of bus bar 320 will be described with reference to FIGS. 17 and 18. FIG.

[0101] 17 is a cross-sectional view schematically showing a state in which first member 311 and second member 322 of bus bar 320 are solid-state welded by friction stir welding. FIG. 18 is a cross-sectional view showing the configuration of region 18 in FIG.

[0102] The solid-state welded portion 320A of the busbar 320 is formed by applying friction stir vibration in a direction B along the stacking direction A and the contact surface 321d or the contact surface 322d having the solid-state welded portion, while the first member 321 and the second member 322 are pressed in the stacking direction A. For example, the direction B may be set as the vibration direction. In solid-state welding by friction stir welding, pressure is applied, for example, from the side of the first member 321. In this case, a welding tool is brought into contact with the first member 321, and a holding tool is brought into contact with the second member 322.

[0103] When direction B is set as the vibration direction, the solid-state welded portion 320A is formed by applying vibration linearly within the plane of the vibration direction B while the first member 321 and the second member 322 are pressed against each other in the stacking direction A. The welding tool is vibrated along the vibration direction B. The welding tool may also be vibrated along a direction intersecting with the vibration direction B.

[0104] In solid-state welding by friction stir welding, a welding tool applies friction stir vibrations to a first member and a second member. A holding tool is provided opposite the welding tool via the first member and the second member. The holding tool receives the vibrations of the welding tool via the first member and the second member. With the holding tool fixed, the welding tool is rotated in a circular pattern and linearly scanned along a desired direction B, which is a direction along the contact surface 321d or the contact surface 322d having the solid-state weld, to friction stir weld the first member 321 and the second member 322. For example, direction B may be set as the vibration direction. In this case, the solid-state weld 320A is formed as an indentation in the first member 321 and the second member 322 by friction stir welding or the like. With the first member 321 and the second member 322 sandwiched between the welding tool and the holding tool, the welding tool is rotated in a circular pattern and scanned along the vibration direction B. The welding tool is rotated circularly within a plane defined by the vibration direction B and a direction C intersecting the vibration direction B. The holding tool may be another welding tool having the same function as the welding tool.

[0105] As shown in FIGS. 17 and 18 , a rectangular indentation 321t is formed on the first contact portion 321R of the first member 321 along the direction B by transferring the shape of a convex portion of a welding tool moving in a desired direction B, which is a direction along the contact surface 321d having the solid-state welded portion. For example, direction B may be set as the vibration direction. Specifically, the indentation 321t on the first contact portion 321R is formed by pressure application by the welding tool and friction stir vibration by the welding tool. The first contact portion 321R of the first member 321 has a non-welded region 321w that is in contact with the second contact portion 322R of the second member 322 but is not welded to the second contact portion 322R of the second member 322. The non-welded region 321w of the first contact portion 321R is connected to the non-welded region 321z of the non-contact portion 321S along the vibration direction B of the friction stir welding.

[0106] A rectangular indentation 322t may be formed in the second contact portion 322R of the second member 322, for example, by being biased by a holding tool. The depth of the indentation 322t along the stacking direction A is sufficiently shallower than the depth of the indentation 321t along the stacking direction A. The second contact portion 322R of the second member 322 is in contact with the first contact portion 321R of the first member 321, but has a second non-bonded portion 322w that is not bonded to the first contact portion 321R of the first member 321. The second non-bonded portion 322w of the second contact portion 322R is continuous with the non-bonded region 322z of the second member 322 along the vibration direction B of the friction stir welding.

[0107] In solid-state welding by friction stir welding, pressure may be applied from the side of the second member 322. In this case, a holding tool is brought into contact with the first member 321, and a welding tool is brought into contact with the second member 322.

[0108] Solid state welding using friction stir technology may be substituted by solid state welding using friction welding technology.

[0109] (Advantages of the Bus Bar 320 and the Battery Pack 1 of the First Embodiment) The advantages of the bus bar 320 and the battery pack 1 of the first embodiment will be described.

[0110] The first member 321 of the heterogeneous bonded busbar 320 includes a non-contact portion 321S. The non-contact portion 321S is inclined with respect to a direction B intersecting the stacking direction A and spaced apart from the second contact portion 322R of the second member 322. For example, direction B is a direction along the contact surface 321d having the solid-state bonded portion, or a vibration direction. It is sufficient that at least the tip 322e of the non-contact portion 321S is spaced apart from the second contact portion 322R of the second member 322. The busbar 320 configured in this manner can provide a busbar 320 in which the first member 321 and the second member 322 are satisfactorily solid-state bonded together, and a battery pack 1 including the busbar 320 can be obtained.

[0111] Specifically, for example, when the first member 321 and the second member 322 are solid-state welded in the direction B, the bus bar 320 including the non-contact portion 321S can suppress or prevent the first member 321, which has a relatively high hardness, from contacting or colliding with the second member 322, which has a relatively low hardness, in the direction B. For example, the direction B is a desired direction along the contact surface 321d having the solid-state welded portion. Alternatively, the direction B can be the vibration direction. That is, the bus bar 320 of the first embodiment can suppress or prevent variations in the state of the solid-state weld caused by the first member 321 contacting or colliding with the second member 322. Therefore, the welded state between the first member 321 and the second member 322 in each bus bar 320 can be made relatively uniform.

[0112] Furthermore, the bus bar 320 including the non-contact portion 321S can suppress or prevent the first member 321 from contacting or colliding with the second member 322, causing partial deformation and detachment of the second member 322 and resulting in the generation of powder from the second member 322. Specifically, this can suppress or prevent the tip of the first member 321 from contacting or colliding with the second member 322, causing the surface of the second member 322 to be scraped and resulting in the generation of powder. The powder is a powder-like substance that is partially deformed and detached from the second member 322, and is electrically conductive. The powder is, for example, metal powder. The bus bar 320 suppresses or prevents the powder from adhering to the second member 322 after detaching from it, or from adhering to parts other than the second member 322 after detaching from it.

[0113] Furthermore, the bus bar 320 including the non-contact portion 321S can suppress or prevent linear burrs from being generated on the second member 322 due to partial deformation of the second member 322 caused by contact or collision of the first member 321, which has a relatively high hardness, with the second member 322, which has a relatively low hardness. Specifically, the bus bar 320 can suppress or prevent a situation in which the tip of the first member 321 contacts or collides with the second member 322, causing the surface of the second member 322 to extend relatively short in the stacking direction A and peel off. Linear burrs are, for example, so-called thread burrs. The thread burrs are thread-like burrs formed by partial deformation of the second member 322 and are electrically conductive. The bus bar 320 suppresses or prevents thread burrs from adhering to the second member 322 after being separated from the second member 322, adhering to a location other than the second member 322 after being separated from the second member 322, or being partially connected to the second member 322.

[0114] Furthermore, the bus bar 320 including the non-contact portion 321S can suppress or prevent the second member 322 from partially deforming due to contact or collision between the first member 321 and the second member 322, resulting in the generation of film-like burrs. Specifically, the bus bar 320 can suppress or prevent the surface of the second member 322 from extending relatively long in the stacking direction A and peeling off due to the tip of the first member 321 contacting or colliding with the second member 322. The film-like burrs are so-called shutter burrs. The shutter burrs are film-like burrs formed by partial deformation or the like of the second member 322, and are conductive. The bus bar 320 suppresses or prevents the shutter burrs from adhering to the second member 322 after being separated from the second member 322, from adhering to a location other than the second member 322 after being separated from the second member 322, or from being partially connected to the second member 322.

[0115] Even if the tip of the second member 322, which has a relatively low hardness, comes into contact with or collides with the first member 321, which has a relatively high hardness, the bus bar 320 can suppress or prevent the first member 321 from being partially deformed, etc.

[0116] The powder and burrs are considered foreign matter to the battery pack 1. The powder and burrs can cause short circuits, corrosion, and the like in the battery pack 1. For this reason, it is desirable to be able to suppress or prevent the generation of powder and burrs in the battery pack 1, as in the bus bar 320 of the first embodiment.

[0117] The first member 321 of the bus bar 320 contains copper. The second member 322 contains aluminum. With this configuration, the bus bar 320 can sufficiently electrically connect one battery 100 having a negative electrode terminal 104 containing copper to another battery 100 having a positive electrode terminal 103 containing aluminum. In other words, with this configuration, it is possible to configure a bus bar 320 that is extremely versatile.

[0118] For example, the non-contact portion 321S of the first member 321 of the busbar 320 is located in a region that is relatively closer to the second contact portion 322R than the second attachment portion 322P of the second member 322 in the vibration direction B that intersects with the stacking direction A. With this configuration, the non-contact portion 321S of the first member 321 can be configured to be sufficiently short in the vibration direction B. In other words, with this configuration, the first member 321 can be made relatively small and lightweight. The non-contact portion 321S of the first member 321 is located, for example, in the region of the second bent portion 322Q along the vibration direction B.

[0119] The second member 322 of the bus bar 320 includes a second bent portion 322Q bent from the second contact portion 322R along the stacking direction A between the second contact portion 322R and the second attachment portion 322P. At least the tip 322e of the non-contact portion 321S of the first member 321 is located in an area relatively closer to the second contact portion 322R than the second bent portion 322Q of the second member 322. With this configuration, the non-contact portion 321S of the first member 321 can be configured to be sufficiently short in the vibration direction B. That is, with this configuration, the first member 321 can be made relatively small and lightweight.

[0120] Non-contact portion 321S of first member 321 of bus bar 320 has no region facing second member 322 along direction B orthogonal to stacking direction A. With this configuration, when direction B is set as the vibration direction, even if non-contact portion 321S moves in vibration direction B, interference with second member 322 can be suppressed or prevented.

[0121] The solid-state welded portion 320A of the busbar 320 is formed in a rectangular shape. The longitudinal direction of the solid-state welded portion 320A is along direction C, which intersects with direction B. For example, direction B is the direction along the contact surface 321d having the solid-state welded portion, or the vibration direction. The first contact portion 321R of the first member 321 and the second contact portion 322R of the second member 322 are solid-state welded toward the side opposite to the longitudinal direction of the solid-state welded portion 320A. The first contact portion 321R of the first member 321 and the second contact portion 322R of the second member 322 are solid-state welded toward direction C, which corresponds to the longitudinal direction of the solid-state welded portion 320A. With this configuration, the ridge line of the solid-state welded portion 320A between the first contact portion 321R of the first member 321 and the second contact portion 322R of the second member 322 can be relatively long. The ridge of the solid-state welded portion 320A is a region perpendicular to direction B. Therefore, the first member 321 and the second member 322 can be solid-state welded relatively strongly. It is preferable that the non-contact region 321S of the first member 321 be a tip 321e aligned with the ultrasonic vibration direction in order to effectively mitigate the effects of vibration. For example, the vibration direction is the main vibration direction in direction B intersecting with the stacking direction A, if the main vibration direction is present. For example, it is the direction in which the vibration amount is large. Alternatively, regardless of this, a non-contact region can be formed at the desired tip 321e. This can suppress the effects of vibration, etc. at the desired tip.

[0122] It is also conceivable to form the tip at a longer length. For example, in the first overlapping portion, the tip formed in the non-contact region can be a tip in the longitudinal direction of the first member in the first overlapping portion. Note that in the above description of (the effects of the busbar 320 and the battery pack 1 of the first embodiment), the tip refers to, for example, a tip in a desired direction along the contact surface 321d having the solid-state welded portion of the first member 321. Specifically, it refers to the tip of the first non-contact portion 321S located at a position overlapping the second member 321 in the stacking direction A. Alternatively, it is the tip in the vibration direction of the first member 321.

[0123] (Busbar 610 of Modified Example 1 of First Embodiment) A busbar 610 of Modified Example 1 of the first embodiment will be described with reference to Fig. 19. Fig. 19 is a cross-sectional view showing the busbar 610 of Modified Example 1 of the first embodiment.

[0124] (Configuration of bus bar 610 of modified example 1 of first embodiment) In Fig. 19 of modified example 1 of the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and descriptions thereof are omitted. In Fig. 19 of modified example 1 of the first embodiment, the components different from those in the first embodiment are denoted by different reference numerals as those in the first embodiment, and descriptions thereof are omitted.

[0125] The same configuration includes a configuration that becomes the same when the aspect ratio is changed. For the second modification of the first embodiment and subsequent embodiments, the same configuration also includes a configuration that becomes the same when the aspect ratio is changed. The same configuration includes a configuration that differs only in the ratio of the first contact portion to the first non-contact portion.

[0126] The bus bar 610 corresponds to a heterogeneous joint bus bar. The bus bar 610 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (2). As shown in FIG. 19 , the bus bar 610 has a first member 611 and a second member 322.

[0127] The first contact portion 321R of the first member 611 and the second contact portion 322R of the second member 322 include a solid-state welded portion 610A. The material of the first member 611 is different from the material of the second member 322. The hardness of the first member 611 is higher than the hardness of the second member 322. The first member 611 contains, for example, copper. The second member 322 contains, for example, aluminum.

[0128] As shown in FIG. 19, the first member 611 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 611S.

[0129] As shown in FIG. 19 , the non-contact portion 611S is connected to the first contact portion 321R. The non-contact portion 611S is formed linearly with the first contact portion 321R along the vibration direction B. For example, the non-contact portion 611S is formed linearly from the first contact portion 321R along a direction B that intersects with the stacking direction A. For example, direction B is the vibration direction. Also, for example, the non-contact portion 611S is formed at a position overlapping the second member 321 in the stacking direction A. The non-contact portion 611S is not in contact with the second member 322 in the stacking direction A. A tip 611e of the non-contact portion 611S is spaced apart from the second contact portion 322R of the second member 322. The non-contact portion 611S is spaced apart from the second contact portion 322R of the second member 322. The tip 611e of the non-contact portion 611S faces the second bent portion 322Q of the second member 322 at a distance in the stacking direction A. The non-contact portion 611S is spaced apart from the second member 322 in the stacking direction A by, for example, 0.01 mm or more. The space between the non-contact portion 611S and the second member 322 in the stacking direction A is preferably 0.01 mm or more and 10 mm or less, more preferably 0.15 mm or more and 5 mm or less, and even more preferably 0.3 mm or more and 1 mm or less. Furthermore, for example, the solid-state welded portion formed on the contact surface 321d of the first member 611 is formed at a position that does not overlap with the first mounting portion 321P in the stacking direction A. Alternatively, the solid-state welded portion formed on the contact surface 321d of the first member 611 may be formed away from the back surface of the mounting surface 321a.

[0130] The non-contact portion 611S is located in a region relatively closer to the second contact portion 322R than the second attachment portion 322P of the second member 322 in direction B intersecting the stacking direction A. For example, direction B is the vibration direction. The protrusion length of the non-contact portion 611S in direction B is, for example, 0.2 mm. The protrusion length of the non-contact portion 611S in direction B is preferably 0.1 mm or more and 50 mm or less, more preferably 0.1 mm or more and 10 mm or less, and even more preferably 0.1 mm or more and 1 mm or less. The non-contact portion 611S of the first member 611 does not have a region facing the second member 322 along direction B perpendicular to the stacking direction A.

[0131] (Effects of the bus bar 610 according to the first modification of the first embodiment) The first member 611 of the bus bar 610 regarding heterogeneous joining includes a non-contact portion 611S. The non-contact portion 611S faces and is spaced apart from the second bent portion 322Q of the second member 322 in the stacking direction A. It is sufficient that at least the tip 611e of the non-contact portion 611S is spaced apart from the second bent portion 322Q of the second member 322.

[0132] The bus bar 610 configured in this manner can provide a bus bar 610 in which the first member 611 and the second member 322 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 610 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 611 from contacting or colliding with the second member 322 during solid-state welding, resulting in an uneven joint between the first member 611 and the second member 322. Furthermore, the bus bar 610 can suppress or prevent the leading end of the first member 611 from contacting or colliding with the second member 322 during solid-state welding, resulting in partial deformation and detachment of the second member 322, which can result in powder, thread burrs, and shutter burrs being generated from the second member 322.

[0133] A tip 611e of the non-contact portion 611S of the first member 611 faces and is spaced apart from the second bent portion 322Q of the second member 322 in the stacking direction A. With this configuration, the non-contact portion 611S and the second member 322 can be sufficiently spaced apart.

[0134] (Busbar 620 of Modified Example 2 of First Embodiment) A busbar 620 of Modified Example 2 of the first embodiment will be described with reference to Fig. 20. Fig. 20 is a cross-sectional view showing the busbar 620 of Modified Example 2 of the first embodiment.

[0135] (Configuration of bus bar 620 in modified example 2 of first embodiment) In Fig. 20 of modified example 2 of the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and descriptions thereof are omitted. In Fig. 20 of modified example 2 of the first embodiment, the components different from those in the first embodiment are denoted by different reference numerals as those in the first embodiment, and descriptions thereof are omitted.

[0136] The bus bar 620 corresponds to a heterojunction bus bar. The bus bar 620 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (2). As shown in FIG. 20 , the bus bar 620 has a first member 611 and a second member 622.

[0137] The first contact portion 321R of the first member 611 and the second contact portion 322R of the second member 622 include a solid-state welded portion 620A. The material of the first member 611 is different from the material of the second member 622. The hardness of the first member 611 is higher than the hardness of the second member 622. The first member 611 contains, for example, copper. The second member 622 contains, for example, aluminum.

[0138] 20, the second member 622 includes a second mounting portion 322P, two second bent portions 622Q, and a second contact portion 322R. The second member 622 is integrally formed with the second mounting portion 322P, the two second bent portions 622Q, and the second contact portion 322R in this order.

[0139] As shown in FIG. 20, two second bent portions 622Q are formed continuously between the second contact portion 322R and the second attachment portion 322P.

[0140] For example, the tip 611e of the non-contact portion 611S faces, apart from, two second bent portions 622Q of the second member 622 in the stacking direction A. The non-contact portion 611S of the first member 611 does not have a region facing the second member 622 along the vibration direction B that is perpendicular to the stacking direction A.

[0141] (Effects of the bus bar 620 according to the second modification of the first embodiment)

[0142] The first member 611 of the bus bar 620 for heterogeneous bonding includes a non-contact portion 611S. The non-contact portion 611S faces and separates from two second bent portions 622Q of the second member 622 in the stacking direction A. Three or more second bent portions 622Q may be formed in the bus bar 620.

[0143] The bus bar 620 configured in this manner can provide a bus bar 620 in which the first member 611 and the second member 622 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 620 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 611 from contacting or colliding with the second member 622 during solid-state welding, thereby causing an uneven joint between the first member 611 and the second member 622. Furthermore, the bus bar 620 can suppress or prevent the leading end of the first member 611 from contacting or colliding with the second member 622 during solid-state welding, causing partial deformation and detachment of the second member 622, resulting in the generation of powder, thread burrs, and shutter burrs from the second member 622.

[0144] (Bus bar 630 according to modified example 3 of first embodiment) A bus bar 630 according to modified example 3 of the first embodiment will be described with reference to Fig. 21 and Fig. 22. Fig. 21 is a cross-sectional view showing the bus bar 630 according to modified example 3 of the first embodiment. Fig. 22 is a cross-sectional view showing a first member 631 of the bus bar 630.

[0145] (Configuration of bus bar 630 in modified example 3 of first embodiment) In Fig. 21 of modified example 3 of the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and descriptions thereof are omitted. In Fig. 21 of modified example 3 of the first embodiment, the components different from those in the first embodiment are denoted by different reference numerals as those in the first embodiment, and descriptions thereof are omitted.

[0146] The bus bar 630 corresponds to a heterojunction bus bar. The bus bar 630 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (3). As shown in FIG. 21 , the bus bar 630 has a first member 631 and a second member 322.

[0147] The first contact portion 321R of the first member 631 and the second contact portion 322R of the second member 322 include a solid-state welded portion 630A. The material of the first member 631 is different from the material of the second member 322. The hardness of the first member 631 is higher than the hardness of the second member 322. The first member 631 contains, for example, copper. The second member 322 contains, for example, aluminum.

[0148] As shown in FIG. 21, the first member 631 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 631S.

[0149] As shown in FIG. 21 , the non-contact portion 631S is continuous with the first contact portion 321R. The non-contact portion 631S is not in contact with the second member 322 in the stacking direction A. A tip 631e of the non-contact portion 631S is spaced apart from the second contact portion 322R of the second member 322. The non-contact portion 631S is spaced apart from the second contact portion 322R of the second member 322. The non-contact portion 631S is located in a region that is relatively closer to the second contact portion 322R than the second mounting portion 322P of the second member 322 in direction B that intersects with the stacking direction A. The tip 631e of the non-contact portion 631S is located in a region that is relatively closer to the second contact portion 322R than the second bent portion 322Q of the second member 322. For example, direction B is the vibration direction.

[0150] The tip 631e of the non-contact portion 631S includes a corner 631f1 that is curved in an arc and faces the second member 322 in the stacking direction A. The corner 631f1 may be formed by linearly inclining. The length t2 of the corner 631f1 along the stacking direction A is, for example, 1 / 10 or more of the length t1 of the non-contact portion 631S of the first member 631 along the stacking direction A. The length t2 is, for example, 0.1 mm or more. The corner 631f1 of the non-contact portion 631S is located in a region that is relatively closer to the second contact portion 322R than the second bent portion 322Q of the second member 322. The radius of curvature of the corner 631f1 is, for example, 0.1 mm or more. The non-contact portion 631S of the first member 631 does not face the second member 322 along direction B, which is perpendicular to the stacking direction A. For example, direction B is the vibration direction.

[0151] As shown in FIG. 22 , the tip 631e of the non-contact portion 631S includes a corner 631f2 at a portion facing the corner 631f1 along the stacking direction A. The corner 631f2 is curved in an arc at the tip 631e. The arc shape of the corner 631f2 is smaller than the arc shape of the corner 631f1. The corner 631f2 may be formed by linearly inclining at the tip 631e. The length t3 of the corner 631f2 along the stacking direction A is shorter than the length t2 of the corner 631f1 along the stacking direction A. The first mounting portion 321P includes the corners 631f2 at both ends facing each other along the stacking direction A and farthest from the second member 322 along a direction B perpendicular to the stacking direction A. For example, direction B is the vibration direction.

[0152] (Effects of the bus bar 630 according to the third modification of the first embodiment) The first member 631 of the bus bar 630 regarding heterogeneous joining includes a non-contact portion 631S. A tip 631e of the non-contact portion 631S includes a corner 631f1 that is curved in an arc and faces the second member 322 in the stacking direction A. The corner 631f1 may be formed to be inclined linearly.

[0153] The bus bar 630 configured in this manner can provide a bus bar 630 in which the first member 631 and the second member 322 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 630 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 631 from contacting or colliding with the second member 322 during solid-state welding, resulting in an uneven joint between the first member 631 and the second member 322. Furthermore, the bus bar 630 can suppress or prevent the leading end of the first member 631 from contacting or colliding with the second member 322 during solid-state welding, resulting in partial deformation and detachment of the second member 322, which can result in powder, thread burrs, and shutter burrs being generated from the second member 322.

[0154] The corner 631f1 of the non-contact portion 631S of the first member 631 is located in a region relatively closer to the second contact portion 322R than the second bent portion 322Q of the second member 322. With this configuration, the non-contact portion 631S of the first member 631 can be configured to be sufficiently short in direction B. For example, direction B is a direction along the contact surface 321d of the first member 631 having the solid-state welded portion. Alternatively, direction B is the vibration direction. In other words, with this configuration, the first member 631 can be made relatively smaller and lighter.

[0155] (Busbar 640 of Modified Example 4 of First Embodiment) A busbar 640 of Modified Example 4 of the first embodiment will be described with reference to Fig. 23. Fig. 23 is a cross-sectional view showing the busbar 640 of Modified Example 4 of the first embodiment.

[0156] (Configuration of bus bar 640 in modified example 4 of first embodiment) In Fig. 23 of modified example 4 of the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and descriptions thereof are omitted. In Fig. 23 of modified example 4 of the first embodiment, the components different from those in the first embodiment are denoted by different reference numerals as those in the first embodiment, and descriptions thereof are omitted.

[0157] The bus bar 640 corresponds to a heterojunction bus bar. The bus bar 640 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (4). As shown in FIG. 23 , the bus bar 640 has a first member 611 and a second member 642.

[0158] The first contact portion 321R of the first member 611 and the second contact portion 322R of the second member 642 include a solid-state welded portion 640A. The material of the first member 611 is different from the material of the second member 642. The hardness of the first member 611 is higher than the hardness of the second member 642. The first member 611 contains, for example, copper. The second member 642 contains, for example, aluminum.

[0159] The second member 642 includes an inclined portion 642g between the second contact portion 322R and the second attachment portion 322P, inclined from the second contact portion 322R toward a direction B intersecting the stacking direction A. The inclined portion 642g is formed in the second bent portion 322Q. The tip 611e of the non-contact portion 611S of the first member 611 faces the inclined portion 642g of the second member 642 at a distance in the stacking direction A. The non-contact portion 611S of the first member 611 does not have a region facing the second member 642 along a direction B perpendicular to the stacking direction A. For example, the direction B is a direction along the contact surface 321d of the first member 631 having the solid-state welded portion. Alternatively, the direction B is a vibration direction.

[0160] (Effects of the bus bar 640 according to the fourth modification of the first embodiment) The first member 611 of the bus bar 640 regarding heterogeneous joining includes a non-contact portion 611S. The non-contact portion 611S of the first member 611 faces the inclined portion 642g of the second member 642 at a distance in the stacking direction A. It is sufficient that at least the tip 611e of the non-contact portion 611S of the first member 611 faces the inclined portion 642g of the second member 642 at a distance in the stacking direction A.

[0161] The bus bar 640 configured in this manner can provide a bus bar 640 in which the first member 611 and the second member 642 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 640 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 611 from contacting or colliding with the second member 642 during solid-state welding, resulting in an uneven joint between the first member 611 and the second member 642. Furthermore, the bus bar 640 can suppress or prevent the leading end of the first member 611 from contacting or colliding with the second member 642 during solid-state welding, resulting in partial deformation and detachment of the second member 642, which can result in powder, thread burrs, and shutter burrs being generated from the second member 642.

[0162] A tip 611e of the non-contact portion 611S of the first member 611 faces and is spaced apart from the inclined portion 642g of the second member 642 in the stacking direction A. With this configuration, the non-contact portion 611S and the second member 642 can be sufficiently spaced apart.

[0163] (Busbar 650 according to Modification 5 of First Embodiment) A busbar 650 according to Modification 5 of the first embodiment will be described with reference to Fig. 24. Fig. 24 is a cross-sectional view showing the busbar 650 according to Modification 5 of the first embodiment.

[0164] (Configuration of bus bar 650 of modified example 5 of first embodiment) In Fig. 24 of modified example 5 of the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and descriptions thereof are omitted. In Fig. 24 of modified example 5 of the first embodiment, the components different from those in the first embodiment are denoted by different reference numerals as those in the first embodiment, and descriptions thereof are omitted.

[0165] The bus bar 650 corresponds to a heterogeneous joint bus bar. The bus bar 650 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (5). As shown in FIG. 24 , the bus bar 650 has a first member 611 and a second member 652.

[0166] The first contact portion 321R of the first member 611 and the second contact portion 322R of the second member 652 include a solid-state welded portion 650A. The material of the first member 611 is different from the material of the second member 652. The hardness of the first member 611 is higher than the hardness of the second member 652. The first member 611 contains, for example, copper. The second member 652 contains, for example, aluminum.

[0167] The second member 652 includes a recess 652h between the second contact portion 322R and the second attachment portion 322P, recessed in a direction away from the non-contact portion 611S of the first member 611 with respect to the stacking direction A. A tip 611e of the non-contact portion 611S of the first member 611 is separated from the recess 652h of the second member 652 in the stacking direction A. The length of the recess 652h along the stacking direction A is, for example, 0.05 times or more the length of the second member 652 along the stacking direction A. The length of the recess 652h along the stacking direction A is preferably 0.05 times or more and 0.5 times or less, more preferably 0.07 times or more and 0.3 times or less, and even more preferably 0.1 times or more and 0.2 times or less the length of the second member 652 along the stacking direction A. The bus bar 650 may have curved or inclined outer or inner edges of the recess 652h. The non-contact portion 611S of the first member 611 does not have a region facing the second member 652 along a direction B perpendicular to the stacking direction A. For example, the direction B is a direction along the contact surface 321d having the solid-state welded portion of the first member 631. Alternatively, the direction B is the vibration direction.

[0168] (Effects of the bus bar 650 according to the fifth modification of the first embodiment) The first member 611 of the bus bar 650 for heterogeneous joining includes a non-contact portion 611S. A tip 611e of the non-contact portion 611S of the first member 611 is spaced apart from the recess 652h of the second member 652 in the stacking direction A.

[0169] The bus bar 650 configured in this manner can provide a bus bar 650 in which the first member 611 and the second member 652 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 650 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 611 from contacting or colliding with the second member 652 during solid-state welding, resulting in an uneven joint between the first member 611 and the second member 652. Furthermore, the bus bar 650 can suppress or prevent the leading end of the first member 611 from contacting or colliding with the second member 652 during solid-state welding, resulting in partial deformation and detachment of the second member 652, which can result in powder, thread burrs, and shutter burrs being generated from the second member 652.

[0170] (Busbar 660 of Modified Example 6 of First Embodiment) A busbar 660 of Modified Example 6 of the first embodiment will be described with reference to Fig. 25. Fig. 25 is a cross-sectional view showing the busbar 660 of Modified Example 6 of the first embodiment.

[0171] (Configuration of bus bar 660 of modified example 6 of first embodiment) In Fig. 25 of modified example 6 of the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and descriptions thereof are omitted. In Fig. 25 of modified example 6 of the first embodiment, the components different from those in the first embodiment are denoted by different reference numerals as those in the first embodiment, and descriptions thereof are omitted.

[0172] The bus bar 660 corresponds to a heterogeneous joint bus bar. The bus bar 660 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (1). As shown in FIG. 25 , the bus bar 660 has a first member 661 and a second member 662.

[0173] The first contact portion 321R of the first member 661 and the second contact portion 322R of the second member 662 include a solid-state welded portion 660A. The material of the first member 661 is different from the material of the second member 662. The hardness of the first member 661 is higher than the hardness of the second member 662. The first member 661 contains, for example, copper. The second member 662 contains, for example, aluminum.

[0174] As shown in FIG. 25, the first member 661 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 661S.

[0175] In the bus bar 660, the first contact portion 321R of the first member 661 is located closer to the battery 100 than the second contact portion 322R of the second member 662. That is, the first member 661 and the second member 662 of the bus bar 660 are stacked in the reverse order in the stacking direction A compared to the first member 321 and the second member 322 of the bus bar 320. The first contact portion 321R of the first member 661 is covered by the second contact portion 322R of the second member 662 from the outside of the battery 100. The non-contact portion 661S of the first member 661 is inclined toward the side closer to the battery 100. The tip 661e of the non-contact portion 661S is inclined most toward the side closer to the battery 100. The non-contact portion 661S of the first member 661 has a region facing the second member 662 along direction B perpendicular to the stacking direction A. The non-contact portion 661S of the first member 661 faces the second bent portion 322Q of the second member 662 along a direction B perpendicular to the stacking direction A. For example, the direction B is a direction along the contact surface 321d having the solid-state welded portion of the first member 661. Alternatively, the direction B is a vibration direction.

[0176] (Effects of the bus bar 660 according to the sixth modification of the first embodiment) The first member 661 of the bus bar 660 for heterogeneous bonding includes a non-contact portion 661S. The non-contact portion 661S of the first member 661 is inclined toward the side closer to the battery 100.

[0177] The bus bar 660 configured in this manner can provide a bus bar 660 in which the first member 661 and the second member 662 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 660 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 661 from contacting or colliding with the second member 662 during solid-state welding, thereby causing an uneven joint between the first member 661 and the second member 662. Furthermore, the bus bar 660 can suppress or prevent the leading end of the first member 661 from contacting or colliding with the second member 662 during solid-state welding, causing partial deformation and detachment of the second member 662, thereby causing powder, thread burrs, and shutter burrs to be generated from the second member 662.

[0178] (Busbar 670 of Modified Example 7 of First Embodiment) A busbar 670 of Modified Example 7 of the first embodiment will be described with reference to Fig. 26. Fig. 26 is a cross-sectional view showing the busbar 670 of Modified Example 7 of the first embodiment.

[0179] (Configuration of bus bar 670 of modified example 7 of first embodiment) In Fig. 26 of modified example 7 of the first embodiment, the same components as those in modified example 6 of the first embodiment are assigned the same reference numerals as those in modified example 6 of the first embodiment, and descriptions thereof are omitted. In Fig. 26 of modified example 7 of the first embodiment, the components different from those in modified example 6 of the first embodiment are assigned different reference numerals as those in modified example 6 of the first embodiment, and descriptions thereof are omitted.

[0180] The bus bar 670 corresponds to a heterojunction bus bar. The bus bar 670 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (3). As shown in FIG. 26 , the bus bar 670 has a first member 671 and a second member 662.

[0181] The first contact portion 321R of the first member 671 and the second contact portion 322R of the second member 662 include a solid-state welded portion 670A. The material of the first member 671 is different from the material of the second member 662. The hardness of the first member 671 is higher than the hardness of the second member 662. The first member 671 contains, for example, copper. The second member 662 contains, for example, aluminum.

[0182] As shown in FIG. 26, the first member 671 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 671S.

[0183] The tip 671e of the non-contact portion 671S includes a corner 671f that is curved in an arc and faces the second member 662 in the stacking direction A. The corner 671f may be formed with a linear inclination. The length of the corner 671f along the stacking direction A is, for example, 1 / 10 or more of the length of the contact portion 671R of the first member 671 along the stacking direction A. The non-contact portion 671S is not in contact with the second member 662 in the stacking direction A.

[0184] In the bus bar 670, the first contact portion 321R of the first member 671 is located closer to the battery 100 than the second contact portion 322R of the second member 662. That is, the first member 671 and the second member 662 of the bus bar 670 are stacked in the reverse order in the stacking direction A compared to the first member 321 and the second member 322 of the bus bar 320 of the first embodiment. The first contact portion 321R of the first member 671 is covered by the second contact portion 322R of the second member 662 from the outside of the battery 100. The non-contact portion 671S of the first member 671 has a region facing the second member 662 along direction B perpendicular to the stacking direction A. The non-contact portion 671S of the first member 671 faces the second bent portion 322Q of the second member 662 along direction B perpendicular to the stacking direction A. For example, direction B is a direction along the contact surface 321d having the solid-state welded portion of the first member 631. Alternatively, direction B is a vibration direction.

[0185] (Effects of the bus bar 670 according to the seventh modification of the first embodiment) The first member 671 of the bus bar 670 regarding heterogeneous joining includes a non-contact portion 671S. A tip 671e of the non-contact portion 671S includes a corner 671f that is curved in an arc and faces the second member 662 in the stacking direction A. The corner 671f may be formed so as to be inclined linearly.

[0186] The bus bar 670 configured in this manner can provide a bus bar 670 in which the first member 671 and the second member 662 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 670 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 671 from contacting or colliding with the second member 662 during solid-state welding, resulting in an uneven joint between the first member 671 and the second member 662. Furthermore, the bus bar 670 can suppress or prevent the leading end of the first member 671 from contacting or colliding with the second member 662 during solid-state welding, resulting in partial deformation and detachment of the second member 662, which can result in powder, thread burrs, and shutter burrs being generated from the second member 662.

[0187] (Bus bar 680 according to eighth modification of first embodiment) A bus bar 680 according to an eighth modification of the first embodiment will be described with reference to Fig. 27. Fig. 27 is a cross-sectional view showing the bus bar 680 according to the eighth modification of the first embodiment.

[0188] (Configuration of bus bar 680 in modified example 8 of the first embodiment) In Fig. 27 of modified example 8 of the first embodiment, the same components as those in modified example 6 of the first embodiment are assigned the same reference numerals as those in modified example 6 of the first embodiment, and descriptions thereof are omitted. In Fig. 27 of modified example 8 of the first embodiment, the components different from those in modified example 6 of the first embodiment are assigned different reference numerals as those in modified example 6 of the first embodiment, and descriptions thereof are omitted.

[0189] The bus bar 680 corresponds to a heterogeneous joint bus bar. The bus bar 680 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (5). As shown in FIG. 27 , the bus bar 680 has a first member 681 and a second member 682.

[0190] The first contact portion 321R of the first member 681 and the second contact portion 322R of the second member 682 include a solid-state welded portion 680A. The material of the first member 681 is different from the material of the second member 682. The hardness of the first member 681 is higher than the hardness of the second member 682. The first member 681 contains, for example, copper. The second member 682 contains, for example, aluminum.

[0191] 27, the first member 681 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 681S. As shown in FIG. 27, the second member 682 includes a second attachment portion 322P, a second bent portion 322Q, and a second contact portion 322R.

[0192] The second member 682 includes a recess 682h between the second contact portion 322R and the second attachment portion 322P that is recessed in a direction away from the non-contact portion 681S of the first member 681 with respect to the stacking direction A. A tip 681e of the non-contact portion 681S of the first member 681 is away from the recess 682h of the second member 682 with respect to the stacking direction A.

[0193] In the bus bar 680, the first contact portion 321R of the first member 681 is located closer to the battery 100 than the second contact portion 322R of the second member 682. The first contact portion 321R of the first member 681 is covered by the second contact portion 322R of the second member 682 from the outside of the battery 100. The non-contact portion 681S of the first member 681 has an area facing the second member 682 along direction B perpendicular to the stacking direction A. The non-contact portion 681S of the first member 681 faces the second bent portion 322Q of the second member 682 along direction B perpendicular to the stacking direction A. For example, direction B is a direction along the contact surface 321d of the first member 681 having the solid-state welded portion. Alternatively, direction B is a vibration direction.

[0194] (Effects of the bus bar 680 according to the eighth modification of the first embodiment) The first member 681 of the bus bar 680 for heterogeneous joining includes a non-contact portion 681S. A tip 681e of the non-contact portion 681S of the first member 681 is spaced apart from the recess 682h of the second member 682 in the stacking direction A.

[0195] The bus bar 680 configured in this manner can provide a bus bar 680 in which the first member 681 and the second member 682 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 680 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 681 from contacting or colliding with the second member 682 during solid-state welding, resulting in an uneven joint between the first member 681 and the second member 682. Furthermore, the bus bar 680 can suppress or prevent the leading end of the first member 681 from contacting or colliding with the second member 682 during solid-state welding, resulting in partial deformation and detachment of the second member 682, which can result in powder, thread burrs, and shutter burrs being generated from the second member 682.

[0196] (Bus bar 690 according to 9th modification of the first embodiment) A bus bar 690 according to a 9th modification of the first embodiment will be described with reference to Fig. 28. Fig. 28 is a cross-sectional view showing the bus bar 690 according to the 9th modification of the first embodiment.

[0197] (Configuration of bus bar 690 of modified example 9 of first embodiment) In Fig. 28 of modified example 9 of the first embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and descriptions thereof are omitted. In Fig. 28 of modified example 9 of the first embodiment, the components different from those in the first embodiment are denoted by different reference numerals as those in the first embodiment, and descriptions thereof are omitted.

[0198] The bus bar 690 corresponds to a heterogeneous joint bus bar. The bus bar 690 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (1). As shown in FIG. 28 , the bus bar 690 has a first member 691 and a second member 692.

[0199] The first contact portion 321R of the first member 691 and the second contact portion 322R of the second member 692 include a solid-state welded portion 690A. The material of the first member 691 is different from the material of the second member 692. The hardness of the first member 691 is higher than the hardness of the second member 692. The first member 691 contains, for example, copper. The second member 692 contains, for example, aluminum.

[0200] 28, the first member 691 includes a first attachment portion 321P, a first bent portion 691Q, a first contact portion 321R, and a non-contact portion 321S. As shown in FIG. 28, the second member 692 includes a second attachment portion 322P, a second bent portion 692Q, and a second contact portion 322R.

[0201] As shown in FIG. 28 , the first bent portion 691Q (bent portion) of the first member 691 has a first boundary 691b and a second boundary 692c that curve in the same direction along direction B, which intersects with the stacking direction A. The first contact portion 321R of the first member 691 extends in the same direction as the first mounting portion 321P, via the first bent portion 691Q, along direction B. The first contact portion 321R is formed parallel to the first mounting portion 321P. As shown in FIG. 28 , the second bent portion 692Q (bent portion) of the second member 692 has a first boundary 692b and a second boundary 692c that curve in the same direction along direction B. The second contact portion 322R of the second member 692 extends in the same direction as the second mounting portion 692P, via the second bent portion 692Q, along direction B. The second contact portion 692R is formed parallel to the second attachment portion 692P. The non-contact portion 321S of the first member 691 does not have a region facing the second member 692 along a direction B perpendicular to the stacking direction A. For example, the direction B is a direction along the contact surface 321d having the solid-state welded portion of the first member 691. Alternatively, the direction B is the vibration direction.

[0202] (Effects of the bus bar 690 according to the ninth modification of the first embodiment) The first member 691 of the bus bar 690 regarding heterogeneous joining includes a non-contact portion 321S. The non-contact portion 321S is inclined with respect to a direction B intersecting the stacking direction A and is spaced apart from the second contact portion 322R of the second member 692. It is sufficient that at least the tip 321e of the non-contact portion 321S is spaced apart from the second contact portion 322R of the second member 692. For example, the direction B is a direction along the contact surface 321d of the first member 631 having the solid-state welded portion. Alternatively, the direction B is a vibration direction.

[0203] The bus bar 690 configured in this manner can provide a bus bar 690 in which the first member 691 and the second member 692 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 690 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 691 from contacting or colliding with the second member 692 during solid-state welding, resulting in an uneven joint between the first member 691 and the second member 692. Furthermore, the bus bar 690 can suppress or prevent the leading end of the first member 691 from contacting or colliding with the second member 692 during solid-state welding, resulting in partial deformation and detachment of the second member 692, which can result in powder, string burrs, and shutter burrs being generated from the second member 692.

[0204] (Busbar 710 of Second Embodiment) A busbar 710 of a second embodiment will be described with reference to Fig. 29 and Fig. 30. Fig. 29 is a perspective view showing the busbar 710 of the second embodiment. Fig. 30 is a cross-sectional view showing the busbar 710 of the second embodiment.

[0205] 29 and 30 of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and descriptions thereof are omitted. In FIGS. 29 and 30 of the second embodiment, components different from those in the first embodiment are denoted by different reference numerals as those in the first embodiment, and descriptions thereof are omitted.

[0206] The bus bar 710 corresponds to a heterogeneous joint bus bar. The bus bar 710 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (2). As shown in FIGS. 29 and 30 , the bus bar 710 has a first member 711 and a second member 712.

[0207] The first contact portion 711R of the first member 711 and the second contact portion 712R of the second member 712 include a solid-state welded portion 710A. The material of the first member 711 is different from the material of the second member 712. The hardness of the first member 711 is higher than the hardness of the second member 712. The first member 711 contains, for example, copper. The second member 712 contains, for example, aluminum.

[0208] 29 and 30, the first member 711 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 711R, and a pair of non-contact portions 711S. As shown in Fig. 29 and 30, the second member 712 includes a second attachment portion 322P, a second bent portion 322Q, and a contact portion 722R.

[0209] As shown in FIGS. 29 and 30 , the first contact portion 711R of the first member 711 is continuous with the first bent portion 321Q. The first contact portion 711R is in contact with the second member 712 in the stacking direction A. The first contact portion 711R is formed in a plate shape. The first contact portion 711R has a contact surface 711d formed by direction B and direction C perpendicular to direction B, which is in contact with the second member 712. The first contact portion 711R extends along direction B. The first contact portion 711R does not face the first mounting portion 321P along the stacking direction A. The first contact portion 711R extends in a direction away from the first mounting portion 321P via the first bent portion 321Q. The first contact portion 711R is formed parallel to the first mounting portion 321P.

[0210] As shown in FIGS. 29 and 30 , the pair of non-contact portions 711S of the first member 711 are connected to the first contact portion 711R. The non-contact portion 711S is formed linearly with the first contact portion 711R along direction B. The non-contact portion 711S is not in contact with the second member 712 in the stacking direction A. The tip 711e of the non-contact portion 711S is spaced apart from the second contact portion 712R of the second member 712. The non-contact portion 711S is spaced apart from the second contact portion 712R of the second member 712. The non-contact portion 711S does not have a region facing the second member 712 along direction B, which is perpendicular to the stacking direction A. The non-contact portion 711S of the first member 711 is formed as a pair on both sides of the first contact portion 711R of the first member 711. Each of the pair of non-contact portions 711S of the first member 711 is spaced apart from the second member 712.

[0211] As shown in FIGS. 29 and 30 , the second contact portion 712R of the second member 712 is continuous with the second bent portion 322Q. The second contact portion 712R is in contact with the first member 711 in the stacking direction A. The first contact portion 711R is formed in a plate shape. The second contact portion 712R has a contact surface 712d formed by direction B and direction C perpendicular to direction B, which is in contact with the first member 711. The second contact portion 712R extends along direction B. The second contact portion 712R does not face the second mounting portion 322P along the stacking direction A. The second contact portion 712R extends in a direction B away from the second mounting portion 322P via the second bent portion 322Q. The second contact portion 712R is formed parallel to the second mounting portion 322P.

[0212] As shown in FIG. 29 , the solid-state welded portion 710A is formed, for example, in a rectangular shape when viewed from the stacking direction A. The longitudinal direction of the solid-state welded portion 710A is a direction along direction C intersecting with direction B. The lateral direction of the solid-state welded portion 710A is a direction along direction B. That is, as shown in FIG. 29 , the length of the rectangular solid-state welded portion 710A along direction C intersecting with direction B is longer than the length along direction B. The longitudinal direction of the solid-state welded portion 710A may be a direction along direction B, and the lateral direction may be a direction along direction C intersecting with direction B. In this case, the length of the rectangular solid-state welded portion 710A along direction B is longer than the length along direction C intersecting with direction B. The solid-state welded portion 710A may also be square. In this case, the length of the square solid-state welded portion 710A along direction B is equal to the length along direction C intersecting with direction B.

[0213] (Effects of the bus bar 710 of the second embodiment) The non-contact portions 711S of the first member 711 of the bus bar 710 related to heterogeneous joining are formed as a pair on both sides of the first contact portion 711R of the first member 711. The pair of non-contact portions 711S of the first member 711 are each spaced apart from the second member 712. It is sufficient that at least the tip ends of the pair of non-contact portions 711S are each spaced apart from the second member 712.

[0214] The bus bar 710 configured in this manner can provide a bus bar 710 in which the first member 711 and the second member 712 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 710 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 711 from contacting or colliding with the second member 712 during solid-state welding, resulting in an uneven joint state between the first member 711 and the second member 712. Furthermore, the bus bar 710 can suppress or prevent the leading end of the first member 711 from contacting or colliding with the second member 712 during solid-state welding, resulting in partial deformation and detachment of the second member 712, which can result in powder, string burrs, and shutter burrs being generated from the second member 712.

[0215] The solid-state welded portion 710A of the bus bar 710 is formed in a rectangular shape. The longitudinal direction of the solid-state welded portion 710A is along direction B. The first contact portion 711R of the first member 711 and the second contact portion 712R of the second member 712 are solid-state welded toward the side opposite the longitudinal direction of the solid-state welded portion 710A. The first contact portion 711R of the first member 711 and the second contact portion 712R of the second member 712 are solid-state welded toward direction B, which corresponds to the longitudinal direction of the solid-state welded portion 710A. With this configuration, the ridge line of the solid-state welded portion 710A between the first contact portion 711R of the first member 711 and the second contact portion 712R of the second member 712 can be relatively long. The ridge line of the solid-state welded portion 710A is a region perpendicular to direction B. Therefore, the first member 711 and the second member 712 can be solid-state welded relatively strongly. In the above description of the second embodiment, for example, the direction B is a direction intersecting the stacking direction A. Alternatively, the direction B is a direction along the contact surface 321d having the solid-state welded portion of the first member 631. Alternatively, the direction B is a vibration direction.

[0216] (Busbar 720 of Modified Example 1 of Second Embodiment) A busbar 720 of Modified Example 1 of the second embodiment will be described with reference to Fig. 31. Fig. 31 is a cross-sectional view showing the busbar 720 of Modified Example 1 of the second embodiment.

[0217] (Configuration of bus bar 720 of modified example 1 of second embodiment) In Fig. 31 of modified example 1 of the second embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 31 of modified example 1 of the second embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment, and descriptions thereof are omitted.

[0218] The bus bar 720 corresponds to a heterogeneous joint bus bar. The bus bar 720 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (6). As shown in FIG. 31 , the bus bar 720 has a first member 721 and a second member 722.

[0219] The first contact portion 711R of the first member 721 and the second contact portion 712R of the second member 722 include a solid-state welded portion 720A. The material of the first member 721 is different from the material of the second member 722. The hardness of the first member 721 is higher than the hardness of the second member 722. The first member 721 contains, for example, copper. The second member 722 contains, for example, aluminum.

[0220] As shown in Fig. 31 , the first member 721 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 711R, and a pair of non-contact portions 721S. As shown in Fig. 31 , the second member 722 includes a second attachment portion 322P, a second bent portion 322Q, and a contact portion 722R. The length of the first member 721 along direction B is the same as the length of the second member 722 along direction B.

[0221] The tip ends 721e of the pair of non-contact portions 721S of the first member 721 include corners 721f that are curved in an arc and face the second member 722 in the stacking direction A. The corners 721f may be formed with a linear inclination. The length of the corners 721f along the stacking direction A is, for example, 1 / 10 or more of the length of the first contact portions 711R of the first member 721 along the stacking direction A. The radius of curvature of the corners 721f is, for example, 0.1 mm or more. The non-contact portions 721S of the first member 721 do not have a region that faces the second member 722 along direction B that is perpendicular to the stacking direction A.

[0222] (Effects of the bus bar 720 according to the first modification of the second embodiment) The tip 721e of the non-contact portion 721S of the first member 721 is spaced apart from the second member 722. The tip 721e of the non-contact portion 721S includes a corner 721f that is curved in an arc and faces the second member 722 in the stacking direction A. The corner 721f may be formed so as to be inclined linearly.

[0223] The bus bar 720 configured in this manner can provide a bus bar 720 in which the first member 721 and the second member 722 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 720 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 721 from contacting or colliding with the second member 722 during solid-state welding, resulting in an uneven joint between the first member 721 and the second member 722. Furthermore, the bus bar 720 can suppress or prevent the leading end of the first member 721 from contacting or colliding with the second member 722 during solid-state welding, resulting in partial deformation and detachment of the second member 722, which can result in powder, thread burrs, and shutter burrs being generated from the second member 722.

[0224] (Busbar 730 of Modification 2 of Second Embodiment) A busbar 730 of Modification 2 of the second embodiment will be described with reference to Fig. 32. Fig. 32 is a cross-sectional view showing the busbar 730 of Modification 2 of the second embodiment.

[0225] (Configuration of bus bar 730 of modified example 2 of second embodiment) In Fig. 32 of modified example 2 of the second embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 32 of modified example 2 of the second embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment, and descriptions thereof are omitted.

[0226] The bus bar 730 corresponds to a heterogeneous joint bus bar. The bus bar 730 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (6). As shown in FIG. 32 , the bus bar 730 has a first member 711 and a second member 732.

[0227] The first contact portion 711R of the first member 711 and the second contact portion 732R of the second member 732 include a solid-state welded portion 730A. The material of the first member 711 is different from the material of the second member 732. The hardness of the first member 711 is higher than the hardness of the second member 732. The first member 711 contains, for example, copper. The second member 732 contains, for example, aluminum.

[0228] 32 , the second member 732 includes a second attachment portion 322P, a second bent portion 322Q, and a second contact portion 732R. The length of the second member 732 in the direction B is the same as the length of the first member 711 in the direction B.

[0229] The tips 732e of the second contact portion 732R of the second member 732 at both ends along the vibration direction B include arc-shaped corners 732f that face the first member 711 in the stacking direction A. The corners 732f may be formed with a linear inclination. The length of the corners 732f along the stacking direction A is, for example, 1 / 10 or more of the length of the second contact portion 732R of the second member 732 along the stacking direction A. The radius of curvature of the corners 732f is, for example, 0.1 mm or more. The non-contact portion 711S of the first member 711 is separated from the corners 732f of the second member 732 along the stacking direction A. There is no region of the non-contact portion 711S of the first member 711 that faces the second member 732 along the direction B perpendicular to the stacking direction A.

[0230] (Effects of the bus bar 730 according to the second modification of the second embodiment) In the bus bar 730 relating to heterogeneous joining, the pair of non-contact portions 711S of the first member 711 are spaced apart from the tip 732e of the second contact portion 732R of the second member 732. The tip 732e of the second contact portion 732R includes a corner 732f that faces the first member 711 in the stacking direction A and is curved in an arc. The corner 732f may be formed so as to be inclined linearly.

[0231] The bus bar 730 configured in this manner can provide a bus bar 730 in which the first member 711 and the second member 732 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 730 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 711 from contacting or colliding with the second member 732 during solid-state welding, resulting in an uneven joint between the first member 711 and the second member 732. Furthermore, the bus bar 730 can suppress or prevent the leading end of the first member 711 from contacting or colliding with the second member 732 during solid-state welding, resulting in partial deformation and detachment of the second member 732, which can result in powder, string burrs, and shutter burrs being generated from the second member 732.

[0232] (Bus bar 740 according to modified example 3 of second embodiment) A bus bar 740 according to modified example 3 of the second embodiment will be described with reference to Fig. 33. Fig. 33 is a cross-sectional view showing the bus bar 740 according to modified example 3 of the second embodiment.

[0233] (Configuration of bus bar 740 in modified example 3 of second embodiment) In Fig. 33 of modified example 3 of second embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 33 of modified example 3 of second embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment, and descriptions thereof are omitted.

[0234] The bus bar 740 corresponds to a heterojunction bus bar. The bus bar 740 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (6). As shown in FIG. 33 , the bus bar 740 has a first member 711 and a second member 742.

[0235] The first contact portion 711R of the first member 711 and the second contact portion 712R of the second member 742 include a solid-state welded portion 740A. The material of the first member 711 is different from the material of the second member 742. The hardness of the first member 711 is higher than the hardness of the second member 742. The first member 711 contains, for example, copper. The second member 742 contains, for example, aluminum.

[0236] The second member 742 includes recesses 742h recessed in a direction away from the pair of non-contact portions 711S of the first member 711 with respect to the stacking direction A. The tip 711e of the non-contact portion 711S of the first member 711 is separated from the recesses 742h of the second member 742 in the stacking direction A. The length of the recesses 742h along the stacking direction A is, for example, 0.05 times or more the length of the second contact portion 712R of the second member 742 along the stacking direction A. The length of the recesses 742h along the stacking direction A is preferably 0.05 times or more and 0.5 times or less, more preferably 0.07 times or more and 0.3 times or less, and even more preferably 0.1 times or more and 0.2 times or less the length of the second member 742 along the stacking direction A. The bus bar 740 may have curved or inclined outer or inner edges of the recesses 742h. The non-contact portion 711S of the first member 711 does not have a region that faces the second member 742 along a direction B that is perpendicular to the stacking direction A.

[0237] (Effects of the bus bar 740 according to the third modification of the second embodiment) In the bus bar 740 for heterogeneous joining, the pair of non-contact portions 711S of the first member 711 are spaced apart from the recessed portions 742h of the second member 742 in the stacking direction A. It is sufficient that at least the tips of the pair of non-contact portions 711S are each spaced apart from the recessed portions 742h of the second member 742.

[0238] The bus bar 740 configured in this manner can provide a bus bar 740 in which the first member 711 and the second member 742 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 740 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 711 from contacting or colliding with the second member 742 during solid-state welding, resulting in an uneven joint state between the first member 711 and the second member 742. Furthermore, the bus bar 740 can suppress or prevent the leading end of the first member 711 from contacting or colliding with the second member 742 during solid-state welding, resulting in partial deformation and detachment of the second member 742, which can result in powder, thread burrs, and shutter burrs being generated from the second member 742.

[0239] (Busbar 750 of Modified Example 4 of Second Embodiment) A busbar 750 of Modified Example 4 of the second embodiment will be described with reference to Fig. 34. Fig. 34 is a cross-sectional view showing the busbar 750 of Modified Example 4 of the second embodiment.

[0240] (Configuration of bus bar 750 of modified example 4 of second embodiment) In Fig. 34 of modified example 4 of the second embodiment, the same components as those in the first or second embodiment are assigned the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 34 of modified example 4 of the second embodiment, the components different from those in the first or second embodiment are assigned different reference numerals as those in the first or second embodiment.

[0241] The bus bar 750 corresponds to a heterojunction bus bar. The bus bar 750 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (1). As shown in FIG. 34 , the bus bar 750 has a first member 751 and a second member 722.

[0242] The first contact portion 711R of the first member 751 and the second contact portion 712R of the second member 722 include a solid-state welded portion 750A. The material of the first member 751 is different from the material of the second member 722. The hardness of the first member 751 is higher than the hardness of the second member 722. The first member 751 contains, for example, copper. The second member 722 contains, for example, aluminum.

[0243] In the bus bar 750, a pair of non-contact portions 751S of the first member 751 are inclined in a direction away from the second member 722. A tip 751e of the non-contact portion 751S is inclined most in a direction away from the second member 722. The non-contact portions 751S are inclined so as to rise from the direction B toward the stacking direction A. The non-contact portions 751S of the first member 751 do not have a region that faces the second member 722 along the direction B that is perpendicular to the stacking direction A.

[0244] (Effects of the bus bar 750 according to the fourth modification of the second embodiment) The first member 751 of the bus bar 750 for heterogeneous joining includes a pair of non-contact portions 751S. The non-contact portions 751S of the first member 751 are inclined in a direction away from the second member 722.

[0245] The bus bar 750 configured in this manner can provide a bus bar 750 in which the first member 751 and the second member 722 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 750 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 751 from contacting or colliding with the second member 722 during solid-state welding, resulting in an uneven joint between the first member 751 and the second member 722. Furthermore, the bus bar 750 can suppress or prevent the leading end of the first member 751 from contacting or colliding with the second member 722 during solid-state welding, resulting in partial deformation and detachment of the second member 722, which can result in powder, thread burrs, and shutter burrs being generated from the second member 722.

[0246] (Busbar 760 of Modified Example 5 of Second Embodiment) A busbar 760 of Modified Example 5 of the second embodiment will be described with reference to Fig. 35. Fig. 35 is a cross-sectional view showing the busbar 760 of Modified Example 5 of the second embodiment.

[0247] (Configuration of bus bar 760 of modified example 5 of second embodiment) In Fig. 35 of modified example 5 of the second embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 35 of modified example 5 of the second embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment.

[0248] The bus bar 760 corresponds to a heterogeneous joint bus bar. The bus bar 760 is an example of a bus bar according to an embodiment of the present invention, and corresponds to the bus bar of configuration (6). As shown in FIG. 35 , the bus bar 760 has a first member 711 and a second member 762.

[0249] The first contact portion 711R of the first member 711 and the second contact portion 712R of the second member 762 include a solid-state welded portion 760A. The material of the first member 711 is different from the material of the second member 762. The hardness of the first member 711 is higher than the hardness of the second member 762. The first member 711 contains, for example, copper. The second member 762 contains, for example, aluminum.

[0250] The second member 762 has a pair of tips 762e that face the pair of non-contact portions 711S of the first member 711 in the stacking direction A and are inclined toward the side closer to the battery 100. The non-contact portions 711S of the first member 711 do not have a region that faces the second member 762 along direction B that is perpendicular to the stacking direction A.

[0251] (Effect of busbar 760 of variant 5 of second embodiment) In busbar 760 for heterogeneous joining, a pair of non-contact portions 711S of first member 711 of busbar 760 are separated from a pair of tips 762e of second member 762 that are inclined in a direction away from first member 711.

[0252] The bus bar 760 configured in this manner can provide a bus bar 760 in which the first member 711 and the second member 762 are satisfactorily solid-state welded together, and a battery pack 1 including the bus bar 760 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 711 from contacting or colliding with the second member 762 during solid-state welding, resulting in an uneven joint state between the first member 711 and the second member 762. Furthermore, the bus bar 760 can suppress or prevent the leading end of the first member 711 from contacting or colliding with the second member 762 during solid-state welding, resulting in partial deformation and detachment of the second member 762, which can result in powder, thread burrs, and shutter burrs being generated from the second member 762.

[0253] (Bus bar 810 of third embodiment) A bus bar 810 of a third embodiment will be described with reference to Fig. 36 and Fig. 37. Fig. 36 is a cross-sectional view showing the bus bar 810 of the third embodiment. Fig. 37 is a cross-sectional view showing a part of the bus bar 810 of the third embodiment.

[0254] 36 and 37 of the third embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In FIGS. 36 and 37 of the third embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment, and descriptions thereof are omitted.

[0255] The bus bar 810 corresponds to a homogeneous joint bus bar. The bus bar 810 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of configurations (1) and (7). As shown in FIGS. 36 and 37 , the bus bar 810 has a first member 811 and a second member 812.

[0256] The first contact portion 321R of the first member 811 and the second contact portion 322R of the second member 812 include a solid-state welded portion 810A. The material of the first member 811 is the same as the material of the second member 812. The hardness of the first member 811 is the same as the hardness of the second member 812. The first member 811 and the second member 812 each contain aluminum, for example. The first member 811 and the second member 812 may each contain copper.

[0257] 36, the first member 811 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 321S (first non-contact portion). The second member 812 includes a second attachment portion 322P, a second bent portion 322Q, a second contact portion 322R, and a non-contact portion 812S (second non-contact portion).

[0258] As shown in FIG. 36 , the non-contact portion 812S is continuous with the first contact portion 321R. A tip 812e of the non-contact portion 812S includes a corner 812f that faces the first member 811 in the stacking direction A and is curved in an arc. The corner 812f may be formed by sloping linearly. The length of the corner 812f along the stacking direction A is, for example, 1 / 10 or more of the length of the second contact portion 322R of the second member 812 along the stacking direction A.

[0259] The second contact portion 322R of the second member 812 is covered by the first contact portion 321R of the first member 811 from the outside of the battery 100. The non-contact portion 321S of the first member 811 does not have a region facing the second member 812 along direction B perpendicular to the stacking direction A. The non-contact portion 812S of the second member 812 has a region facing the first member 811 along direction B perpendicular to the stacking direction A. The non-contact portion 812S of the second member 812 faces the first bent portion 321Q of the first member 811 along direction B perpendicular to the stacking direction A.

[0260] The non-contact portion 321S of the first member 811 and the non-contact portion 322S of the second member 812 face each other along a direction B perpendicular to the stacking direction A, via the solid-state welded portion 810A. In the above description of the modified example of the second embodiment, for example, the direction B is a direction intersecting the stacking direction A. Alternatively, the direction B is a direction along the contact surface 321d having the solid-state welded portion of the first member 631. Alternatively, the direction B is a vibration direction.

[0261] (Advantages of the bus bar 810 of the third embodiment) The first member 811 of the bus bar 810 regarding homogeneous joining includes a non-contact portion 321S. The non-contact portion 321S is inclined with respect to a direction B intersecting the stacking direction A and is spaced apart from the second contact portion 322R of the second member 812. It is sufficient that at least the tip 321e of the non-contact portion 321S is spaced apart from the second contact portion 322R of the second member 812. The second member 812 of the bus bar 810 includes a non-contact portion 812S. The tip 812e of the non-contact portion 812S faces the first member 811 in the stacking direction A and includes a corner 812f that is curved in an arc shape. The corner 812f may be formed to be inclined linearly.

[0262] The bus bar 810 configured as described above can provide a bus bar 810 in which the first member 811 and the second member 812 are solid-state welded satisfactorily, and a battery pack 1 including the bus bar 810 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 811 from contacting or colliding with the second member 812 during solid-state welding, resulting in an uneven bond between the first member 811 and the second member 812. Furthermore, the bus bar 810 can suppress or prevent the leading end of the first member 811 from contacting or colliding with the second member 812 during solid-state welding, resulting in partial deformation and detachment of the second member 812, which can result in powder, thread burrs, and shutter burrs being generated from the second member 812. Similarly, the bus bar 810 can suppress or prevent the leading end of the second member 812 from contacting or colliding with the first member 811.

[0263] The first member 811 and the second member 812 each contain aluminum, for example. The first member 811 and the second member 812 may each contain copper. According to this configuration, the first end bus bar 310 may be formed by the first member 811 and the second member 812 each containing aluminum. Furthermore, the second end bus bar 330 may be formed by the first member 811 and the second member 812 each containing copper.

[0264] (Busbar 820 of Modified Example 1 of Third Embodiment) A busbar 820 of Modified Example 1 of the third embodiment will be described with reference to Fig. 38. Fig. 38 is a cross-sectional view partially showing the busbar 820 of Modified Example 1 of the third embodiment.

[0265] The bus bar 820 corresponds to a homogeneous joint bus bar. The bus bar 820 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of configurations (1) and (8). As shown in FIG. 38 , the bus bar 820 has a first member 811 and a second member 822.

[0266] The first contact portion 321R of the first member 811 and the second contact portion 322R of the second member 822 include a solid-state welded portion 810A. The material of the first member 811 is the same as the material of the second member 822. The hardness of the first member 811 is the same as the hardness of the second member 822. The first member 811 and the second member 822 each contain aluminum, for example. The first member 811 and the second member 822 may each contain copper.

[0267] At least a tip 822 e of a second non-contact portion 822 S of the second member 822 is inclined with respect to a direction B intersecting the stacking direction A and is spaced apart from the first contact portion 321 R of the first member 811 .

[0268] (Effect of busbar 820 of variant example 1 of third embodiment) In the busbar 820 for homogeneous joining, at least the tip 822e of the second non-contact portion 822S of the second member 822 is inclined with respect to direction B intersecting with the stacking direction A and is spaced apart from the first contact portion 321R of the first member 811.

[0269] The bus bar 820 configured in this manner can provide a bus bar 820 in which the first member 811 and the second member 822 are satisfactorily solid-state welded, and a battery pack 1 including the bus bar 820 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 811 from contacting or colliding with the second member 822 during solid-state welding, resulting in an uneven bond between the first member 811 and the second member 822. Furthermore, the bus bar 820 can suppress or prevent the leading end of the first member 811 from contacting or colliding with the second member 822 during solid-state welding, resulting in partial deformation and detachment of the second member 822, which can cause powder, thread burrs, and shutter burrs to form on the second member 822. Similarly, the bus bar 820 can suppress or prevent the leading end of the second member 822 from contacting or colliding with the first member 811.

[0270] (Busbar 830 of Modified Example 2 of Third Embodiment) A busbar 830 of Modified Example 2 of the third embodiment will be described with reference to Fig. 39. Fig. 39 is a cross-sectional view partially showing the busbar 830 of Modified Example 2 of the third embodiment.

[0271] The bus bar 830 corresponds to a homogeneous joint bus bar. The bus bar 830 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of configurations (1) and (9). As shown in FIG. 39 , the bus bar 830 has a first member 831 and a second member 832.

[0272] The first contact portion 321R of the first member 831 and the second contact portion 322R of the second member 832 include a solid-state welded portion 810A. The material of the first member 831 is the same as the material of the second member 832. The hardness of the first member 831 is the same as the hardness of the second member 832. The first member 831 and the second member 832 each contain aluminum, for example. The first member 831 and the second member 832 may each contain copper.

[0273] The first member 831 includes a recess 831h between the first contact portion 321R and the first attachment portion 321P that is recessed in a direction away from the second non-contact portion 832S of the second member 832 with respect to the stacking direction A. At least a tip 832e of the second non-contact portion 832S of the second member 832 is away from the recess 831h of the first member 831.

[0274] (Effects of Bus Bar 830 of Modification 2 of Third Embodiment) In the bus bar 830 for homogeneous joining, at least the tip 832 e of the second non-contact portion 832S of the second member 832 is separated from the recess 831 h of the first member 831 .

[0275] The bus bar 830 configured as described above can provide a bus bar 830 in which the first member 831 and the second member 832 are solid-state welded satisfactorily, and a battery pack 1 including the bus bar 830 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 831 from contacting or colliding with the second member 832 during solid-state welding, resulting in an uneven bond between the first member 831 and the second member 832. Furthermore, the bus bar 830 can suppress or prevent the leading end of the first member 831 from contacting or colliding with the second member 832 during solid-state welding, resulting in partial deformation and detachment of the second member 832, which can result in powder, thread burrs, and shutter burrs being generated from the second member 832. Similarly, the bus bar 830 can suppress or prevent the leading end of the second member 832 from contacting or colliding with the first member 831.

[0276] (Busbar 840 of Modification 3 of Third Embodiment) A busbar 840 of Modification 3 of the third embodiment will be described with reference to Fig. 40. Fig. 40 is a cross-sectional view showing the busbar 840 of Modification 3 of the third embodiment.

[0277] (Configuration of bus bar 840 of modified example 3 of third embodiment) In Fig. 40 of modified example 3 of the third embodiment, the same components as those in the first or second embodiment are assigned the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 40 of modified example 3 of the third embodiment, the components different from those in the first or second embodiment are assigned different reference numerals as those in the first or second embodiment.

[0278] The bus bar 840 corresponds to a homogeneous joint bus bar. The bus bar 840 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of the configurations (2) and (7). As shown in FIG. 40 , the bus bar 840 has a first member 841 and a second member 812.

[0279] The first contact portion 321R of the first member 841 and the second contact portion 322R of the second member 812 include a solid-state welded portion 840A. The material of the first member 841 is the same as the material of the second member 812. The hardness of the first member 841 is the same as the hardness of the second member 812. The first member 841 and the second member 812 each contain aluminum, for example. The first member 841 and the second member 812 may each contain copper.

[0280] As shown in FIG. 40, the first member 841 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 611S (first non-contact portion).

[0281] The non-contact portion 611S is formed linearly with the first contact portion 321R along the direction B. The non-contact portion 611S is not in contact with the second member 812 in the stacking direction A.

[0282] The second contact portion 322R of the second member 812 is covered by the first contact portion 321R of the first member 841 from the outside of the battery 100. The non-contact portion 611S of the first member 841 does not have a region that faces the second member 812 along direction B that is perpendicular to the stacking direction A.

[0283] A tip 812e of the non-contact portion 812S of the second member 812 includes a corner 812f that is curved in an arc and faces the first member 841 in the stacking direction A. The corner 812f may be formed by inclining linearly.

[0284] The non-contact portion 611S of the first member 841 and the non-contact portion 812S of the second member 812 face each other along a direction B perpendicular to the stacking direction A, with a solid-state welded portion 840A interposed therebetween.

[0285] (Effects of the bus bar 840 according to the third modification of the third embodiment) The first member 841 of the bus bar 840 regarding homogeneous joining includes a non-contact portion 611S. The non-contact portion 611S is not in contact with the second member 812 in the stacking direction A. The non-contact portion 611S is formed, for example, linearly along the direction B with the first contact portion 321R. The second member 812 of the bus bar 840 includes a non-contact portion 812S. A tip 812e of the non-contact portion 812S faces the first member 841 in the stacking direction A and includes a corner 812f that is curved in an arc shape. The corner 812f may be formed by inclining the line.

[0286] The bus bar 840 configured as described above can provide a bus bar 840 in which the first member 841 and the second member 812 are solid-state welded satisfactorily, and a battery pack 1 including the bus bar 840 can be obtained. Specifically, this can suppress or prevent the tip of the first member 841 from contacting or colliding with the second member 812 during solid-state welding, resulting in an uneven bond between the first member 841 and the second member 812. Furthermore, the bus bar 840 can suppress or prevent the tip of the first member 841 from contacting or colliding with the second member 812 during solid-state welding, resulting in partial deformation and detachment of the second member 812, which can result in powder, thread burrs, and shutter burrs being generated from the second member 812. Similarly, the bus bar 840 can suppress or prevent the tip of the second member 812 from contacting or colliding with the first member 841.

[0287] (Bus bar 850 according to fourth modification of the third embodiment) A bus bar 850 according to a fourth modification of the third embodiment will be described with reference to Fig. 41. Fig. 41 is a cross-sectional view showing the bus bar 850 according to the fourth modification of the third embodiment.

[0288] (Configuration of bus bar 850 in modified example 4 of third embodiment) In Fig. 41 of modified example 4 of the third embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 41 of modified example 4 of the third embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment, and descriptions thereof are omitted.

[0289] The bus bar 850 corresponds to a homogeneous joint bus bar. The bus bar 850 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of the configurations (3) and (7). As shown in FIG. 41 , the bus bar 850 has a first member 851 and a second member 812.

[0290] The first contact portion 321R of the first member 851 and the second contact portion 322R of the second member 812 include a solid-state welded portion 850A. The material of the first member 851 is the same as the material of the second member 812. The hardness of the first member 851 is the same as the hardness of the second member 812. The first member 851 and the second member 812 each contain aluminum, for example. The first member 851 and the second member 812 may each contain copper.

[0291] As shown in FIG. 41, the first member 851 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 321R, and a non-contact portion 631S (first non-contact portion).

[0292] The tip 631e of the non-contact portion 631S includes a corner 631f1 that is curved in an arc and faces the second member 812 in the stacking direction A. The corner 631f1 may be formed by inclining linearly. The non-contact portion 631S is not in contact with the second member 812 in the stacking direction A.

[0293] The second contact portion 322R of the second member 812 is covered by the first contact portion 321R of the first member 851 from the outside of the battery 100. The non-contact portion 631S of the first member 851 does not have a region that faces the second member 812 along direction B that is perpendicular to the stacking direction A.

[0294] The non-contact portion 631S of the first member 851 and the non-contact portion 812S of the second member 812 face each other along a direction B perpendicular to the stacking direction A, with a solid-state welded portion 850A interposed therebetween.

[0295] (Effects of bus bar 850 according to fourth modification of third embodiment) The first member 851 of the bus bar 850 regarding homogeneous joining includes a non-contact portion 631S. A tip 631e of the non-contact portion 631S includes a corner 631f1 that is curved in an arc and faces the second member 812 in the stacking direction A. The corner 631f1 may be formed with a linear inclination. The second member 812 of the bus bar 850 includes a non-contact portion 812S. A tip 812e of the non-contact portion 812S includes a corner 812f that is curved in an arc and faces the first member 851 in the stacking direction A. The corner 812f may be formed with a linear inclination.

[0296] The bus bar 850 configured as described above can provide a bus bar 850 in which the first member 851 and the second member 812 are solid-state welded well, and a battery pack 1 including the bus bar 850 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 851 from contacting or colliding with the second member 812 during solid-state welding, resulting in an uneven bond between the first member 851 and the second member 812. Furthermore, the bus bar 850 can suppress or prevent the leading end of the first member 851 from contacting or colliding with the second member 812 during solid-state welding, resulting in partial deformation and detachment of the second member 812, which can result in powder, thread burrs, and shutter burrs being generated from the second member 812. Similarly, the bus bar 850 can suppress or prevent the leading end of the second member 812 from contacting or colliding with the first member 851.

[0297] (Bus bar 860 according to modified example 5 of the third embodiment) A bus bar 860 according to modified example 5 of the third embodiment will be described with reference to Fig. 42. Fig. 42 is a cross-sectional view showing the bus bar 860 according to modified example 5 of the third embodiment.

[0298] (Configuration of bus bar 860 in modified example 5 of third embodiment) In Fig. 42 of modified example 5 of the third embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 42 of modified example 5 of the third embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment, and descriptions thereof are omitted.

[0299] The bus bar 860 corresponds to a homogeneous joint bus bar. The bus bar 860 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of the configurations (4) and (7). As shown in FIG. 42 , the bus bar 860 has a first member 841 and a second member 862.

[0300] The first contact portion 321R of the first member 841 and the second contact portion 322R of the second member 862 include a solid-state welded portion 860A. The material of the first member 841 is the same as the material of the second member 862. The hardness of the first member 841 is the same as the hardness of the second member 862. The first member 841 and the second member 862 each contain aluminum, for example. The first member 841 and the second member 862 may each contain copper.

[0301] The second member 862 includes an inclined portion 862g (second inclined portion) that is inclined from the second contact portion 322R toward a direction B intersecting the stacking direction A between the second contact portion 322R and the second attachment portion 322P. The inclined portion 862g is formed in the second bent portion 322Q. A tip end 611e of the non-contact portion 611S (first non-contact portion) of the first member 841 faces the inclined portion 862g of the second member 862 at a distance in the stacking direction A.

[0302] The second contact portion 322R of the second member 862 is covered by the first contact portion 321R of the first member 841 from the outside of the battery 100. The non-contact portion 611S of the first member 841 does not have a region that faces the second member 862 along direction B that is perpendicular to the stacking direction A.

[0303] The non-contact portion 611S of the first member 841 and the non-contact portion 812S of the second member 862 face each other along a direction B perpendicular to the stacking direction A, with a solid-state welded portion 860A interposed therebetween.

[0304] (Advantages of the bus bar 860 according to the fifth modification of the third embodiment) The first member 841 of the bus bar 860 regarding homogeneous joining includes a non-contact portion 611S. A tip 611e of the non-contact portion 611S (first non-contact portion) of the first member 841 faces, at a distance, an inclined portion 862g of the second member 862 in the stacking direction A. The second member 862 of the bus bar 860 includes a non-contact portion 812S. A tip 812e of the non-contact portion 812S faces the first member 841 in the stacking direction A and includes a corner 812f that is curved in an arc. The corner 812f may be formed with a linear inclination.

[0305] The bus bar 860 configured as described above can provide a bus bar 860 in which the first member 841 and the second member 862 are solid-state welded well, and a battery pack 1 including the bus bar 860 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 841 from contacting or colliding with the second member 862 during solid-state welding, resulting in an uneven bond between the first member 841 and the second member 862. Furthermore, the bus bar 860 can suppress or prevent the leading end of the first member 841 from contacting or colliding with the second member 862 during solid-state welding, resulting in partial deformation and detachment of the second member 862, which can cause powder, thread burrs, and shutter burrs to form on the second member 862. Similarly, the bus bar 860 can suppress or prevent the leading end of the second member 862 from contacting or colliding with the first member 841.

[0306] (Bus bar 870 according to sixth modification of the third embodiment) A bus bar 870 according to a sixth modification of the third embodiment will be described with reference to Fig. 43. Fig. 43 is a cross-sectional view showing the bus bar 870 according to the sixth modification of the third embodiment.

[0307] (Configuration of bus bar 870 in modified example 6 of third embodiment) In Fig. 43 of modified example 6 of the third embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 43 of modified example 6 of the third embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment, and descriptions thereof are omitted.

[0308] The bus bar 870 corresponds to a homogeneous joint bus bar. The bus bar 870 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of the configurations (5) and (7). As shown in FIG. 43 , the bus bar 870 has a first member 841 and a second member 872.

[0309] The first contact portion 321R of the first member 841 and the second contact portion 322R of the second member 872 include a solid-state welded portion 870A. The material of the first member 841 is the same as the material of the second member 872. The hardness of the first member 841 is the same as the hardness of the second member 872. The first member 841 and the second member 872 each contain aluminum, for example. The first member 841 and the second member 872 may each contain copper.

[0310] The second member 872 includes a recess 872h between the second contact portion 322R and the second attachment portion 322P that is recessed in a direction away from the non-contact portion 611S (first non-contact portion) of the first member 841 with respect to the stacking direction A. A tip 611e of the non-contact portion 611S of the first member 841 is away from the recess 872h of the second member 872 with respect to the stacking direction A.

[0311] The second contact portion 322R of the second member 872 is covered by the first contact portion 321R of the first member 841 from the outside of the battery 100.

[0312] The non-contact portion 611S of the first member 841 and the non-contact portion 812S of the second member 872 face each other along a direction B perpendicular to the stacking direction A, with a solid-state welded portion 870A interposed therebetween.

[0313] (Effects of the bus bar 870 according to the sixth modification of the third embodiment) The first member 841 of the bus bar 870 with respect to homogeneous joining includes a non-contact portion 611S. A tip 611e of the non-contact portion 611S of the first member 841 is spaced apart from the recess 872h of the second member 872 in the stacking direction A. The second member 872 of the bus bar 870 includes a non-contact portion 812S. The tip 812e of the non-contact portion 812S includes a corner 812f that faces the first member 841 in the stacking direction A and is curved in an arc. The corner 812f may be formed with a linear inclination.

[0314] The bus bar 870 configured as described above can provide a bus bar 870 in which the first member 841 and the second member 872 are solid-state welded well, and a battery pack 1 including the bus bar 870 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 841 from contacting or colliding with the second member 872 during solid-state welding, resulting in an uneven bond between the first member 841 and the second member 872. Furthermore, the bus bar 870 can suppress or prevent the leading end of the first member 841 from contacting or colliding with the second member 872 during solid-state welding, resulting in partial deformation and detachment of the second member 872, which can cause powder, thread burrs, and shutter burrs to form on the second member 872. Similarly, the bus bar 870 can suppress or prevent the leading end of the second member 872 from contacting or colliding with the first member 841.

[0315] (Bus bar 880 according to seventh modification of the third embodiment) A bus bar 880 according to a seventh modification of the third embodiment will be described with reference to Fig. 44. Fig. 44 is a cross-sectional view showing the bus bar 880 according to the seventh modification of the third embodiment.

[0316] (Configuration of bus bar 880 in modified example 7 of third embodiment) In Fig. 44 of modified example 7 of the third embodiment, the same components as those in the first or second embodiment are denoted by the same reference numerals as those in the first or second embodiment, and descriptions thereof are omitted. In Fig. 44 of modified example 7 of the third embodiment, the components different from those in the first or second embodiment are denoted by different reference numerals as those in the first or second embodiment, and descriptions thereof are omitted.

[0317] The bus bar 880 corresponds to a homogeneous joint bus bar. The bus bar 880 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of configurations (1) and (7). As shown in FIG. 44 , the bus bar 880 has a first member 881 and a second member 882.

[0318] The first contact portion 321R of the first member 881 and the second contact portion 322R of the second member 882 include a solid-state welded portion 880A. The material of the first member 881 is the same as the material of the second member 882. The hardness of the first member 881 is the same as the hardness of the second member 882. The first member 881 and the second member 882 each contain aluminum, for example. The first member 881 and the second member 882 may each contain copper.

[0319] As shown in Fig. 44, the first member 881 includes a first attachment portion 321P, a first bent portion 691Q, a first contact portion 321R, and a non-contact portion 321S (first non-contact portion). As shown in Fig. 44, the second member 882 includes a second attachment portion 322P, a second bent portion 692Q, a second contact portion 322R, and a non-contact portion 812S.

[0320] The non-contact portion 321S (first non-contact portion) of the first member 881 and the non-contact portion 812S of the second member 882 face each other along a direction B perpendicular to the stacking direction A, with a solid-state welded portion 880A interposed therebetween.

[0321] (Effects of the bus bar 880 according to the seventh modified example of the third embodiment) The first member 881 of the bus bar 880 regarding homogeneous joining includes a non-contact portion 321S. The non-contact portion 321S is inclined with respect to a direction B intersecting the stacking direction A and is spaced apart from the second contact portion 322R of the second member 882. It is sufficient that at least the tip 321e of the non-contact portion 321S is spaced apart from the second contact portion 322R of the second member 882. The second member 882 of the bus bar 880 includes a non-contact portion 812S. The tip 812e of the non-contact portion 812S faces the first member 881 in the stacking direction A and includes a corner 812f that is curved in an arc shape. The corner 812f may be formed with a linear inclination.

[0322] The bus bar 880 configured as described above can provide a bus bar 880 in which the first member 881 and the second member 882 are solid-state welded well, and a battery pack 1 including the bus bar 880 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 881 from contacting or colliding with the second member 882 during solid-state welding, resulting in an uneven bond between the first member 881 and the second member 882. Furthermore, the bus bar 880 can suppress or prevent the leading end of the first member 881 from contacting or colliding with the second member 882 during solid-state welding, resulting in partial deformation and detachment of the second member 882, which can cause powder, thread burrs, and shutter burrs to form on the second member 882. Similarly, the bus bar 880 can suppress or prevent the leading end of the second member 882 from contacting or colliding with the first member 881. In the above description of the third embodiment (including modifications), for example, the direction B is a direction intersecting the stacking direction A. Alternatively, the direction B is a direction along the contact surface 321d having the solid-state welded portion of the first member 631. Alternatively, the direction B is a vibration direction.

[0323] (Busbar 910 of Fourth Embodiment) A busbar 910 of a fourth embodiment will be described with reference to Fig. 45. Fig. 45 is a cross-sectional view showing the busbar 910 of the fourth embodiment.

[0324] (Configuration of bus bar 910 of fourth embodiment) In Fig. 45 of the fourth embodiment, the same components as those in the first, second, or third embodiment are denoted by the same reference numerals as those in the first, second, or third embodiment, and descriptions thereof are omitted. In Fig. 45 of the fourth embodiment, the components different from those in the first, second, or third embodiment are denoted by different reference numerals as those in the first, second, or third embodiment, and descriptions thereof are omitted.

[0325] The bus bar 910 corresponds to a homogeneous joint bus bar. The bus bar 910 is an example of a bus bar according to two embodiments of the present invention, and corresponds to the bus bars of the configurations (1) and (6). As shown in FIG. 45 , the bus bar 910 has a first member 911 and a second member 912.

[0326] The first contact portion 711R of the first member 911 and the second contact portion 712R of the second member 912 include a solid-state welded portion 910A. The material of the first member 911 is the same as the material of the second member 912. The hardness of the first member 911 is the same as the hardness of the second member 912. The first member 911 and the second member 912 each contain aluminum, for example. The first member 911 and the second member 912 may each contain copper.

[0327] As shown in Fig. 45 , the first member 911 includes a first attachment portion 321P, a first bent portion 321Q, a first contact portion 711R, and a pair of non-contact portions 721S. As shown in Fig. 31 , the second member 912 includes a second attachment portion 322P, a second bent portion 322Q, and a second contact portion 712R. The length of the first member 911 along direction B is the same as the length of the second member 912 along direction B.

[0328] The tips 721e of the pair of non-contact portions 721S of the first member 911 include corners 721f that are curved in an arc and face the second member 912 in the stacking direction A. The corners 721f may be formed with a linear inclination. The length of the corners 721f along the stacking direction A is, for example, 1 / 10 or more of the length of the first contact portions 711R of the first member 911 along the stacking direction A. The radius of curvature of the corners 721f is, for example, 0.1 mm or more. The non-contact portions 721S of the first member 911 do not have a region that faces the second member 912 along direction B that is perpendicular to the stacking direction A.

[0329] (Effects of the bus bar 910 of the fourth embodiment) The tip 721e of the non-contact portion 721S of the first member 911 is separated from the second member 912. The tip 721e of the non-contact portion 721S includes a corner 721f that is curved in an arc and faces the second member 912 in the stacking direction A. The corner 721f may be formed so as to be inclined linearly.

[0330] The configuration of the first member 911 and the second member 912 of the bus bar 910 of the fourth embodiment may be replaced with the configuration of the first member and the second member of any one of the second to fifth modifications of the third embodiment.

[0331] The bus bar 910 configured as described above can provide a bus bar 910 in which the first member 911 and the second member 912 are solid-state welded well, and a battery pack 1 including the bus bar 910 can be obtained. Specifically, this can suppress or prevent the leading end of the first member 911 from contacting or colliding with the second member 912 during solid-state welding, resulting in an uneven bond between the first member 911 and the second member 912. Furthermore, the bus bar 910 can suppress or prevent the leading end of the first member 911 from contacting or colliding with the second member 912 during solid-state welding, resulting in partial deformation and detachment of the second member 912, which can result in powder, thread burrs, and shutter burrs being generated from the second member 912. Similarly, the bus bar 910 can suppress or prevent the leading end of the second member 912 from contacting or colliding with the first member 911. In the above description of the fourth embodiment, for example, the direction B is a direction intersecting the stacking direction A. Alternatively, the direction B is a direction along the contact surface 321d having the solid-state welded portion of the first member 631. Alternatively, the direction B is a vibration direction.

[0332] 46 and 47 of the fifth embodiment, the same components as those in the first, second, third, or fourth embodiment are denoted by the same reference numerals as those in the first, second, third, or fourth embodiment, and descriptions thereof are omitted. In FIGS. 46 and 47 of the fifth embodiment, the components different from those in the first, second, third, or fourth embodiment are denoted by different reference numerals as those in the first, second, third, or fourth embodiment.

[0333] Fig. 46 is a perspective view showing a bus bar 1010 according to the fifth embodiment. Fig. 47 is a cross-sectional view showing the bus bar 1010 according to the fifth embodiment.

[0334] The bus bar 1010 corresponds to a heterojunction bus bar. The bus bar 1010 is an example of a bus bar according to the third embodiment of the present invention. As shown in FIGS. 46 and 47 , the bus bar 1010 has a first member 321 and a second member 1012.

[0335] The first contact portion 321R of the first member 321 and the second contact portion 322R of the second member 1012 include a solid-state welded portion 1010A. The material of the first member 321 is different from the material of the second member 1012. The hardness of the first member 321 is higher than the hardness of the second member 1012. The first member 321 contains, for example, copper. The second member 1012 contains, for example, aluminum.

[0336] The non-contact portion of the first member 321 is connected in an annular shape from the outside of the first contact portion 321R to the first contact portion 321R on a plane intersecting the stacking direction A of the first contact portion 321R. The non-contact portion of the first member 321 has an annular portion that is not in contact with the second member 1012 in the stacking direction A. The non-contact portion of the first member 321 includes a first non-contact portion 321S1, a second non-contact portion 321S2, a third non-contact portion 321S3, and a fourth non-contact portion 321S4. The non-contact portion of the first member 321 annularly surrounds the edge of the second contact portion 322R of the second member 1012 on a plane intersecting the stacking direction A. The non-contact portions of the first member 321, namely, the first non-contact portion 321S1, the second non-contact portion 321S2, the third non-contact portion 321S3, and the fourth non-contact portion 321S4, are connected in a ring shape from the outside of the first contact portion 321R to the first contact portion 321R. The first non-contact portion 321S1 and the third non-contact portion 321S3 each face a first vibration direction B1. The first vibration direction B1 is the same direction as the vibration direction B in the first embodiment. The second non-contact portion 321S2 and the fourth non-contact portion 321S4 each face a second vibration direction B2. The second vibration direction B2 is the same direction as the direction C that intersects with the vibration direction B in the first embodiment.

[0337] The second member 1012 includes a second contact portion 322R that is in contact with the first contact portion 321R of the first member 321 in the stacking direction. The second member 1012 has a relatively short width in the second vibration direction B2. The length of the second contact portion 322R of the second member 1012 in the first vibration direction B1 is shorter than the length of the first contact portion 321R of the first member 321 in the first vibration direction B1. Both ends of the second contact portion 322R of the second member 1012 in the first vibration direction B1 are located more inward in the first vibration direction B1 than both ends of the first contact portion 321R of the first member 321 in the first vibration direction B1. The length of the second contact portion 322R of the second member 1012 in the second vibration direction B2 is shorter than the length of the first contact portion 321R of the first member 321 in the second vibration direction B2. Both ends in the second vibration direction B2 of the second contact portion 322R of the second member 1012 are located more inward in the second vibration direction B2 than both ends in the second vibration direction B2 of the first contact portion 321R of the first member 321. The second contact portion 322R of the second member 1021 is spaced apart from the first non-contact portion 321S1, the second non-contact portion 321S2, the third non-contact portion 321S3, and the fourth non-contact portion 321S4 of the first member 321.

[0338] The first contact portion 321R of the first member 321 of the busbar 1010 and the second contact portion 322R of the second member 1012 include a solid-state welded portion 1010A. The solid-state welded portion 1010A is formed in the first contact portion 321R located inside the non-contact portion of the first member 321 and the second contact portion 322R of the second member 1012 along a plane intersecting the stacking direction A and along a region in which the non-contact portion of the first member 321 is located.

[0339] (Solid-state joining of bus bar 1010 by ultrasonic welding) Solid-state joining of bus bar 1010 by ultrasonic welding will be described with reference to Fig. 48. The solid-state joining by ultrasonic welding described with reference to Fig. 9 will be omitted.

[0340] FIG. 48 is a schematic diagram showing solid-state welding of the bus bar 1010 of the fifth embodiment.

[0341] The solid-state welded portion 1010A of the busbar 1010 is formed by applying ultrasonic vibrations W2 in an arc shape in the first vibration direction B1 and the second vibration direction B2 while the first member 321 and the second member 1012 are pressed in the stacking direction A. The vibration shape of the vibrations W2 is, for example, a perfect circle. The vibration shape of the vibrations W2 may be an elliptical shape elongated along the second vibration direction B2. The vibration shape of the vibrations W2 may be an elliptical shape elongated along the first vibration direction B1. The vibration shape of the vibrations W2 may be any two-dimensional geometric shape. In solid-state welding by ultrasonic welding, pressure is applied from the side of the first member 321, for example. In this case, the horn 11 is brought into contact with the first member 321, and the anvil 12 is brought into contact with the second member 1012. In solid-state welding by ultrasonic welding, pressure may be applied from the side of the second member 1012. In this case, the anvil 12 is brought into contact with the first member 321 , and the horn 11 is brought into contact with the second member 1012 .

[0342] (Effects of the busbar 1010 of the fifth embodiment) The non-contact portion of the first member 321 is connected in an annular shape from the outside of the first contact portion 321R to the first contact portion 321R on a plane intersecting the stacking direction A of the first contact portion 321R. The non-contact portion of the first member 321 includes a first non-contact portion 321S1, a second non-contact portion 321S2, a third non-contact portion 321S3, and a fourth non-contact portion 321S4. The non-contact portion of the first member 321 surrounds the second contact portion 322R of the second member 1012 in an annular shape on a plane intersecting the stacking direction A. The first non-contact portion 321S1, the second non-contact portion 321S2, the third non-contact portion 321S3, and the fourth non-contact portion 321S4, which correspond to the tip of the first member 321, are spaced apart from the second contact portion 322R of the second member 1021.

[0343] The busbar 1010 configured as described above can provide a busbar 1010 in which the first member 321 and the second member 1012 are solid-state welded satisfactorily, and a battery pack 1 including the busbar 1010 can be obtained. Specifically, this configuration can suppress or prevent the leading end of the first member 321 from contacting or colliding with the second member 1012 during solid-state welding, resulting in an uneven bond between the first member 321 and the second member 1012. Furthermore, the busbar 1010 can suppress or prevent the leading end of the first member 321 from contacting or colliding with the second member 1012 during solid-state welding, resulting in partial deformation and detachment of the second member 1012, which can result in powder, thread burrs, and shutter burrs being generated from the second member 1012. Similarly, the busbar 1010 can suppress or prevent the leading end of the second member 1012 from contacting or colliding with the first member 321.

[0344] The configurations of the first member 321 and the second member 1012 of the busbar 1010 of the fifth embodiment may be replaced with the configurations of the first member and the second member of the modified example of the first embodiment. The configurations of the first member 321 and the second member 1012 of the busbar 1010 of the fifth embodiment may be replaced with the configurations of the first member and the second member of the second embodiment or the modified example of the second embodiment. In these configurations, the length of the second contact portion of the second member in the first vibration direction B1 is configured to be shorter than the length of the first contact portion of the first member in the first vibration direction B1. Both ends of the second contact portion of the second member in the first vibration direction B1 are positioned more inward than both ends of the first contact portion of the first member in the first vibration direction B1 in the first vibration direction B1. The length of the second contact portion of the second member in the second vibration direction B2 is configured to be shorter than the length of the first contact portion of the first member in the second vibration direction B2. Both ends of the second contact portion of the second member in the second vibration direction B2 are positioned more inward in the second vibration direction B2 than both ends of the first contact portion of the first member in the second vibration direction B2.

[0345] (Busbar 1110 of Sixth Embodiment) A busbar 1110 of a sixth embodiment will be described with reference to Fig. 49 and Fig. 50. Fig. 49 is a perspective view showing the busbar 1110 of the sixth embodiment. Fig. 50 is a cross-sectional view showing the busbar 1110 of the sixth embodiment.

[0346] The bus bar 1110 is an example of a bus bar according to an embodiment of the present invention. The first mounting portion 321P is attached to the negative terminal 104 (electrode terminal) of the battery 100. The first mounting portion 321P, which is connected to the negative terminal of the battery, has a mounting surface 321a of the first mounting portion 321P that faces the battery negative terminal and has a negative electrode connection surface that is connected to the battery negative terminal, and a back surface 1111g of the first mounting portion 321P that has a negative electrode connection back surface that is located on the opposite side (back surface side) of the mounting surface 321a of the first mounting portion 321P.

[0347] The second mounting portion 322P is attached to the positive terminal 103 (electrode terminal) of the battery 100. The second mounting portion 322P connected to the positive terminal of the battery has a mounting surface 322a of the second mounting portion 322P that faces the battery positive terminal and has a positive electrode connection surface that is connected to the battery positive terminal, and a back surface 1112g of the second mounting portion 322P that has a positive electrode connection back surface that is located on the opposite side (back surface side) of the mounting surface 322a of the second mounting portion 322P.

[0348] The first member 321 and the second member 322 have the following configuration when viewed in direction A, which is the overlapping direction of the second member 322 and the first member 321. The first member 321 and the second member 322 have a first member overlapping portion 1111U and a second member overlapping portion 1112U where a portion of the first member 321 and the second member 322 overlap.

[0349] The first member overlapping portion 1111U and the second member overlapping portion 1112U of the bus bar 1110 have overlapping surfaces that face each other. Specifically, the first member overlapping portion 1111U has a contact surface 321d that faces the second member overlapping portion 1112U. The second member overlapping portion 1112U has a contact surface 322d that faces the first member overlapping portion 1111U.

[0350] The first member overlapping portion 1111U of the first member 321 has a solid-state welded portion 320A with the second member overlapping portion 1112U on the second member 322 side. Similarly, the second member overlapping portion 1112U of the second member 322 has a solid-state welded portion 320A with the first member overlapping portion 1111U on the first member 321 side.

[0351] The first member contact surface 321d of the first member 321 has a solid-state welded portion 320A joined to the contact surface 322d of the second member 322. Similarly, the second member contact surface 322d of the second member 322 has a solid-state welded portion 320A joined to the contact surface 321d of the first member.

[0352] The first member overlapping portion 1111U has a first contact portion 321R of the first member and a non-contact portion 321S of the first member. The second member overlapping portion 1112U has a second contact portion 322R and a non-contact portion 322S of the second member.

[0353] The non-contact portion 321S may be used to mean a region of the first member overlapping portion 1111U that does not come into contact with the second member overlapping portion 1112U. The non-contact portion 322S may be used to mean a region of the second member overlapping portion 1112U that does not come into contact with the first member overlapping portion 1111U.

[0354] For example, by providing the second overlapping portion 1112U and the first overlapping portion 1111U that extend at an angle of approximately 90° from the rising direction of the second bent portion 322Q and the first bent portion 321Q toward the adjacent positive electrode and negative electrode, it is possible to arrange the positive electrode side contact surface 322d of the second overlapping portion 1112U and the negative electrode side contact surface 321d of the negative electrode side first overlapping portion 1111U approximately parallel to the stacking direction of the battery 100. Even if the angle is not approximately 90°, the inclination of the second overlapping portion 1112U or the first overlapping portion 1111U can be set to a predetermined inclination that is closer to the inclination of the surface of the second mounting portion 322P or the first mounting portion 321P than the inclination of the second bent portion 322Q or the first bent portion 321Q.

[0355] When the contact surfaces 321d and 322d are provided parallel to the stacking direction of the battery 100, for example, the stress acting on the contact surfaces 321d and 322d of the busbar 1110 is in the shear direction during charging and discharging of the battery, or when the battery expands and contracts due to long-term use, for example. In this case, it is known that the static strength is several times greater than when stress is applied in the peeling direction. This makes it possible to realize a busbar that is less susceptible to fatigue failure or shear failure.

[0356] The second bending portion 322Q and the first bending portion 321Q also have the advantage that the heights of the second overlapping portion 1112U and the first overlapping portion 1111U can be changed. Advantages thereof include, for example, the following.

[0357] In other words, for example, if a solvent gets mixed in, if the positive electrode terminal 103, the negative electrode terminal 104, the second overlapping portion 1112U, and the first overlapping portion 1111U are at the same height, the areas where the solvent can drip are limited, which creates the problem of the solvent being prone to stagnation.

[0358] On the other hand, if the heights of the positive electrode terminal 103, the negative electrode terminal 104, and the second overlapping portion 1112U and the first overlapping portion 1111U are different, the solvent tends to drip in the direction of lower potential energy, causing the solvent to flow, which has the advantage of making corrosion less likely to occur at the contact surface 322d of the second overlapping portion 1112U and the contact surface 321d of the first overlapping portion 1111U, where the second overlapping portion 1112U and the first overlapping portion 1111U are joined.

[0359] It is generally known that when a solvent is brought into contact with the interface between dissimilar metals, the corrosion rate is several times higher than that of a single metal. Therefore, as a means of suppressing corrosion, it is possible to change the height of the interface between dissimilar metals.

[0360] An example in which the contact surfaces 321d and 322d of the second overlapping portion 1112U and the first overlapping portion 1111U are higher than the surfaces of the positive electrode terminal 103 and the negative electrode terminal 104 is just one example, and the stress relaxation effect can also be obtained if the contact surfaces 321d and 322d of the first overlapping portion 1111U of the second overlapping portion 1112U and the first overlapping portion 1111U are lower than the positive electrode terminal 103 and the negative electrode terminal 104.

[0361] There are no particular limitations on the magnitude of the bending R between the first mounting portion 321P, the second mounting portion 322P and the second refraction portion 322Q, the first refraction portion 321Q, or the magnitude of the bending R between the second refraction portion 322Q, the first refraction portion 321Q and the first overlapping portion 1112U, the first overlapping portion 1111U.

[0362] That is, in the study of this embodiment, it was found that the effects of this embodiment can be obtained whether the bending radius R is large or small. Similarly, it was found that there is an effect of alleviating stress on contact surface 322d of second overlapping portion 1112U and contact surface 321d of first overlapping portion 1111U. The magnitude of bending radius R is preferably 0.001 mm or more and 8 mm or less, more preferably 0.01 mm or more and 4 mm or less, and most preferably 0.1 mm or more and 2 mm or less.

[0363] It is also possible to adjust the first mounting portion 321P, the second bent portion 322Q rising from the first mounting portion 321P, and the rising position of the first bent portion 321Q. In other words, when the distance between the positive electrode terminal 103 and the negative electrode terminal 104 of the battery is fixed, it becomes easy to freely adjust the areas of the joint surfaces of the second overlapping portion 1112U and the first overlapping portion 1111U, and the contact surfaces 321d and 322d including the joint surfaces.

[0364] For example, the contact area between the positive terminal 103, the second mounting portion 322P, and the first mounting portion 321P can be increased, while the overlapping area between the contact surfaces 321d and 322d of the first overlapping portion 1111U and the second overlapping portion 1112U can be narrowed.

[0365] As another example, the contact area between the positive terminal 103, the negative terminal 104 and the second mounting portion 322P, and the first mounting portion can be narrowed, while the overlapping area between the contact surface 321d and the contact surface 322d of the second overlapping portion 1112U and the first overlapping portion 1111U can be widened.

[0366] This means that the desired rising position can be achieved by the stress applied to the contact surfaces 321d and 322d of the second overlapping portion 1112U and the first overlapping portion 1111U of the bus bar 1110. In particular, in this embodiment, the overlapping areas of the contact surfaces 321d and 322d of the second member 322 and the first member 321 are widened. However, other configurations may be used as long as the effects of this embodiment can be obtained.

[0367] When increasing the contact surface 321d of the second member 322 and the first member 321, and the overlapping area of ​​the contact surface 322d, since the distance between the positive electrode terminal 103 and the negative electrode terminal 104 is fixed, it is also important to cover the upper surface of the electrode with the second bending portion 322Q and the first bending portion 321Q without contacting a portion of the upper surface of the adjacent electrode terminal.

[0368] However, the positional relationship between the second refraction portion 322Q and the first refraction portion 321Q is merely an example, and any positional relationship may be used as long as the configuration of this embodiment is satisfied. In other words, the second refraction portion 322Q and the first refraction portion 321Q may be provided at any position as long as the desired overlapping area of ​​the contact surface 321d and the contact surface 322d can be obtained and the desired strength can be obtained.

[0369] For example, the second bending portion 322Q and the first bending portion 321Q may be arranged so as to cover only a portion of the upper surface of one of the adjacent electrode terminals without physical contact, and the second bending portion 322Q and the first bending portion 321Q may be arranged in a positional relationship so as to rise up while covering the upper surface of the other battery terminal, or the second bending portion 322Q and the first bending portion 321Q may be arranged so as to cover only a portion of the upper surfaces of both of the adjacent electrode terminals without physical contact.

[0370] As long as the contact area with the electrode terminal can be secured, the second member 322 and the second mounting portion 322P and the first mounting portion 321P of the first member 321 may cover both adjacent electrode terminals and be in physical contact with each other. The proportion of the area where the second member 322 and the second mounting portion 322P and the first mounting portion 321P cover the upper surfaces of the electrode terminals and are physically and electrically connected may be any proportion as long as electrical connection between the electrode terminals and the bus bar 1110 is obtained and the contact area is a desired value, but is preferably 20% or more, more preferably 50% or more, and even more preferably 70% or more.

[0371] In addition to these, if the electrical resistance value of the busbar 1110 and the bonding strength with the electrode terminal are within the desired values, in order to reduce the material of the busbar 1110, it is possible to leave the entire terminal surface of the electrode terminal uncovered, rather than covering all of the terminal surfaces of adjacent electrode terminals on the upper surface of the electrode terminal, for example, by narrowing the width of the busbar 1110.

[0372] (Advantages of the busbar 1110 of the sixth embodiment) A busbar to be mounted on a battery pack includes a first member having electrical conductivity, a second member having electrical conductivity, an overlapping portion where a portion of the first member and the second member are overlapped, and a solid-state welded portion formed in the overlapping portion, wherein the first member includes a first attachment portion having a first attachment surface connected to either a first battery or an electrical device and a first back surface located opposite the first attachment surface, the first overlapping portion constituting the overlapping portion, and the solid-state welded portion formed in the first overlapping portion and spaced apart from the first back surface, while the second member includes a second attachment portion having a second attachment surface connected to either a second battery or an electrical device when the first member is connected to the first battery, or to the first battery when the first member is connected to an electrical device, and a second back surface located opposite the second attachment surface, the second overlapping portion constituting the overlapping portion, and the solid-state welded portion formed in the second overlapping portion and spaced apart from the second back surface. The first overlapping portion has a non-contact portion located away from the second overlapping portion in the overlapping direction between the first overlapping portion and the second overlapping portion, and a tip formed on the non-contact portion. This prevents, for example, the tip (also called the end or tip edge) at the overlapping portion of the metal plate with a higher hardness from contacting the overlapping portion of the other metal plate, thereby preventing the tip from scraping the other metal plate. In metal components with overlapping portions, if the tip of one component comes into contact with the overlapping surface of the other component, scraping, friction, and stress will be applied. This feature prevents unnecessary heat and stress from being applied, providing a product with a highly reliable joining structure.

[0373] The above has been described as a product in which metal members with different hardnesses are stacked together, but even if the hardnesses are the same, the tip of one of the overlapping parts can suppress the above-mentioned effect on the other metal plate, thereby providing a product with a highly reliable joint structure.

[0374] In order to effectively mitigate the effects of vibration, it is preferable that the tip of the non-contact portion of the overlapping portion be a tip that is in a direction B that intersects with the stacking direction A, preferably in the direction of ultrasonic vibration. The vibration direction is the main vibration direction if there is a main vibration direction. For example, it is the direction in which the vibration amount is large. Alternatively, regardless of this, the desired tip can be formed in the non-contact region. The effects of vibration, etc. at the desired tip can be suppressed. Direction B is, for example, the contact surface 321d having the solid-state welded portion or a direction along the contact surface.

[0375] For example, it is conceivable to form the tip at a long length. For example, in the first overlapping portion, the tip formed in the non-contact region may be a tip in the longitudinal direction of the first member in the first overlapping portion.

[0376] Since the solid-state welded portion is located away from the back surface of the attachment portion to the battery electrode, there is greater freedom in managing the attachment portion or its attachment surface that connects to the battery, and in the shape of the attachment. This allows for the construction of a battery pack with highly reliable connections. Furthermore, the solid-state welded portion may be located in a position that does not overlap with the attachment portion to the battery electrode in the stacking direction A of the first and second members.

[0377] In the first overlapping portion 1111U, not all of the tip 321e may have the non-contact portion 321S. For example, a predetermined range of the tip 321e may be formed in the non-contact portion 321S.

[0378] As an example, the first member is a first metal plate made of a first metal material, such as a copper-based metal containing copper, and the second member is a second metal plate made of a second metal material that is less hard than the first metal plate, such as an aluminum-based metal containing aluminum.

[0379] The first overlapping portion 1111U and the second overlapping portion 1112U can have the following relationship: The first overlapping portion 1111U is positioned farther from the battery 100 than the second overlapping portion 1112U. Alternatively, the second overlapping portion 1112U is positioned farther from the battery than the first overlapping portion 1111U. This saves space around the battery electrode terminals, contributing to a smaller battery pack.

[0380] Either the second overlapping portion 1112U of the second member 322 or the first overlapping portion 1111U of the first member 321 can be located on the side farther from the battery to which the second member 322 or the first member 321 is connected. For example, the first overlapping portion 1112U can be located on the side farther from the battery.

[0381] When the first overlapping portion 1111U is provided with the tip 321e having the non-contact portion 321S, it becomes easy to check the state of the tip 321e.

[0382] For example, the first member overlapping portion 1111U may be located closer to the battery. If the first overlapping portion 1111U has a tip 321e with a non-contact portion 321S, the tip 321e is located closer to the battery, making it difficult for external foreign matter to enter. This makes it possible to provide a battery pack with a highly reliable connection.

[0383] The above-described features preferably include at least one of the following features (1), (2), (3), (4), and (5).

[0384] (1) The non-contact portion of the first member has a first portion between the solid-state welded portion and the tip, and a second portion located closer to the tip than the first portion, and the second portion has a larger distance between the first overlapping portion and the second overlapping portion in the overlapping direction than the first portion. Specifically, as an example, this is the content described in the first embodiment (e.g., FIGS. 12 and 13 and the description thereof).

[0385] Configuration (2) The first overlapping portion has a first contact surface including the solid-state welded portion and in contact with the second overlapping portion, the second overlapping portion has a second contact surface including the solid-state welded portion and in contact with the first overlapping portion, and the second overlapping portion of the second member has a bent portion between the solid-state welded portion and the tip that is bent in a direction away from the first contact surface in the overlapping direction. Specifically, as an example, this is the content described in Modifications 1 and 2 (e.g., Figures 19 and 20 and their descriptions).

[0386] Configuration (3) The tip of the first overlapping portion has a first corner that is arcuate or inclined on the second overlapping portion side, and if there is a second corner that is arcuate or inclined formed on the side of the tip opposite the second overlapping portion side, or a third corner that is arcuate or inclined formed on the tip of the first attachment portion, the length of the first corner in the overlapping direction is longer than the length of the second corner or the third corner. Specifically, one example is the content described in Modification 3 (e.g., Figures 21 and 22 and their descriptions).

[0387] Configuration (4) The second overlapping portion has a recess or an inclined portion recessed in a direction away from the first overlapping portion, the recess or the inclined portion being arranged to overlap with the tip in the overlapping direction, and the first overlapping portion has a tip that is arranged not to contact the recess or the inclined portion. Specifically, as an example, this is the content described in Modifications 4 and 5 (e.g., Figures 23 and 24 and their descriptions).

[0388] Configuration (5) The first overlapping portion has a first contact surface including the solid-state welded portion and in contact with the second overlapping portion, the second overlapping portion has a second contact surface including the solid-state welded portion and in contact with the first overlapping portion, and the first overlapping portion has, at a portion of the tip side of the solid-state welded portion in the overlapping direction, an inclined portion inclined away from the second contact surface, and the inclined portion has a non-contact portion located away from the second contact surface, and a tip formed on the non-contact portion. Specifically, as an example, the content described in the first embodiment.

[0389] The length t2 of the corner 631f1 is longer than the length t3 of the corner 631f2 or any of the lengths t3 of the corners at the tip of the first mounting portion 321P. A high-quality bus bar can be efficiently produced by focusing processing on the corners located at the first overlapping portion 1111U and adjacent to the second member 322. More preferably, the length t2 of the corner 631f1 is longer than the length t3 of the corner 631f2 and any of the lengths t3 of the tip of the first mounting portion 321P.

[0390] (Battery Assembly of Other Embodiments) The battery assembly of the present invention is not limited to the configuration of the battery assembly described in the embodiments, and can be configured appropriately based on the content described in the claims.

[0391] The embodiments are described in detail or simply to clearly explain the present invention, and it is not necessary to include all of the components described, or components not shown may be included. Furthermore, some of the components of the embodiments may be deleted, replaced with components of other embodiments, or combined with other embodiments. For example, the bus bar 820 of Modification 1 of the third embodiment shown in FIG. 38 may be combined with the bus bar 840 of Modification 3 of the third embodiment shown in FIG. 40.

[0392] 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, nickel-cadmium batteries, and lead batteries can be used as the batteries 100. For example, a lithium-ion capacitor, an electrolytic double layer capacitor, or other storage element can be used as the batteries 100. The batteries 100 are not limited to secondary batteries. For example, a primary battery can be used as the batteries 100.

[0393] DESCRIPTION OF SYMBOLS 1 Battery pack, 11 Horn, 12 Anvil, 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, 311 First member, 312 Second member, 320 Bus bar, 320A Solid-state welded portion, 321 First member, 321P First mounting portion, 321Q First bent portion, 321R first contact portion, 321S non-contact portion, 321S1 first non-contact portion, 321S2 second non-contact portion, 321S3 third non-contact portion, 321S4 fourth non-contact portion, 321a mounting surface, 321b first boundary, 321c second boundary, 321d contact surface, 321e tip, 321t indentation portion, 321v non-indentation portion, 321w non-bonding region, 321z non-bonding region, 322 second member, 322P second mounting portion, 322Q second bent portion, 322R second contact portion, 322S non-contact portion, 322a mounting surface, 322b first boundary, 322c second boundary, 322d contact surface, 322e tip, 322t: Indented portion, 322v: Non-indented portion, 322w: Non-bonded region, 322z: Non-bonded region, 330: Second end bus bar, 331: First portion, 332: Second portion, 332i: Insertion hole, 340: Bus bar holder, 340a: Opening, 340b: Holding portion, 340c: Insertion portion, 400: Voltage detection unit, 401: Voltage detection terminal, 402: Electric wire, 500: Temperature measurement unit, 501: Temperature sensor, 502: Electric wire, 610: Bus bar, 610A: Solid-state welded portion, 611: First member, 611S: Non-contact portion, 611e: Tip, 620: Bus bar, 620A: Solid-state welded portion,622 Second member, 622Q Second bent portion, 630 Bus bar, 630A Solid-state welded portion, 631 First member, 631S Non-contact portion, 631e Tip, 631f1 Corner portion, 631f2 Corner portion, 640 Bus bar, 640A Solid-state welded portion, 642 Second member, 642g Inclined portion, 650 Bus bar, 650A Solid-state welded portion, 652 Second member, 652h Recessed portion, 660 Bus bar, 660A Solid-state welded portion, 661 First member, 661S Non-contact portion, 661e Tip, 662 Second member, 670 Bus bar, 670A Solid-state welded portion, 671 First member, 671R Contact portion, 671S Non-contact portion, 671e Tip, 671f Corner portion, 680 Bus bar, 680A Solid-state welded portion, 681 First member, 681S Non-contact portion, 681e Tip, 682 Second member, 682h Recessed portion, 690 Bus bar, 690A Solid-state welded portion, 691 First member, 691Q First bent portion, 691b First boundary, 692 Second member, 692P Second attachment portion, 692Q Second bent portion, 692R Second contact portion, 692b First boundary, 692c Second boundary, 710 Bus bar, 710A Solid-state welded portion, 711 First member, 711R First contact portion, 711S Non-contact portion, 711d Contact surface, 711e tip, 712 second member, 712R second contact portion, 712d contact surface, 720 bus bar, 720A solid-state welded portion, 721 first member, 721S non-contact portion, 721e tip, 721f corner portion, 722 second member, 722R contact portion, 730 bus bar, 730A solid-state welded portion, 732 second member, 732R second contact portion, 732e tip, 732f corner portion, 740 bus bar, 740A solid-state welded portion, 742 second member, 742h recessed portion, 750 bus bar, 750A solid-state welded portion, 751 first member, 751S non-contact portion, 751e tip, 760 bus bar, 760A solid-state welded portion, 762 second member, 762e tip, 810 bus bar,810A solid-state welded portion, 811 first member, 812 second member, 812S non-contact portion, 812e tip, 812f corner portion, 820 bus bar, 822 second member, 822S second non-contact portion, 822e tip, 830 bus bar, 831 first member, 831h recessed portion, 832 second member, 832S second non-contact portion, 832e tip, 840 bus bar, 840A solid-state welded portion, 841 first member, 850 bus bar, 850A solid-state welded portion, 851 first member, 860 bus bar, 860A solid-state welded portion, 862 second member, 862g inclined portion, 870 bus bar, 870A Solid-state welded portion, 872 second member, 872h recessed portion, 880 bus bar, 880A solid-state welded portion, 881 first member, 882 second member, 910 bus bar, 910A solid-state welded portion, 911 first member, 912 second member, 1010 bus bar, 1010A solid-state welded portion, 1012 second member, 1110 bus bar, 1110 bus bar, 1111U overlapping portion, 1111g back surface, 1112U overlapping portion, 1112g back surface, X stacking direction (of battery pack 1), Y width direction (of battery pack 1), Z height direction (of battery pack 1), A stacking direction (of first member 321 etc. and second member 322 etc.), B Vibration direction (in solid-state joining of the first member 321 etc. and the second member 322 etc.), B1: first vibration direction, B2: second vibration direction, C: direction perpendicular to vibration direction B.

Claims

1. A battery comprising a plurality of batteries, and a bus bar connected to one of the batteries and another of the batteries, or connected to one of the batteries and connected to an external electrical device, wherein the bus bar comprises: a first member having electrical conductivity; and a second member having electrical conductivity, laminated and joined to the first member, and having a hardness lower than that of the first member, wherein the first member comprises: a first mounting portion attached to an electrode terminal of one of the batteries or to the electrical device, a first contact portion connected to the first mounting portion and in contact with the second member in the stacking direction, and a non-contact portion connected to the first contact portion and at least partially not in contact with the second member in the stacking direction, wherein the second member comprises: a second mounting portion attached to an electrode terminal of the other of the batteries, and a second contact portion connected to the second mounting portion and in contact with the first contact portion of the first member in the stacking direction, wherein the first contact portion of the first member and the second contact portion of the second member comprise solid-state welded portions, the non-contact portion of the first member is located closer to the second attachment portion of the second member than the solid-state welded portion; and the present invention includes at least one or more of the following configurations (1), (2), (3), (4), (5), and (6), wherein in configuration (1), at least a tip of the non-contact portion of the first member is inclined with respect to a direction intersecting the stacking direction and separated from the second contact portion of the second member; in configuration (2), the first member has the solid-state welded portion formed in a location that does not overlap with the first attachment portion in the stacking direction; and the second member includes, between the second contact portion and the second attachment portion, a bent portion that is bent from the second contact portion from one end side to the other end side in the stacking direction; and at least a tip of the non-contact portion of the first member is separated from the bent portion of the second member; and in configuration (3), the tip of the non-contact portion of the first member includes a curved or inclined corner that faces the second member in the stacking direction; In the configuration (4), a length of the corner portion of the first member along the stacking direction is 1 / 10 or more of a length of the non-contact portion of the first member along the stacking direction, or 0.1 mm or more.The second member includes an inclined portion between the second contact portion and the second mounting portion, inclined from the second contact portion in a direction intersecting the stacking direction, and at least a tip of the non-contact portion of the first member is separated from the inclined portion of the second member. In the configuration (5), the second member includes a recess between the second contact portion and the second mounting portion, recessed in a direction away from the non-contact portion of the first member with respect to the stacking direction, and at least a tip of the non-contact portion of the first member is separated from the recess of the second member. In the configuration (6), the non-contact portion of the first member is formed in a pair on both sides of the first contact portion of the first member, and at least a tip of the pair of non-contact portions of the first member is each separated from the second member.

2. The battery pack according to claim 1, wherein the first member includes copper, and the second member includes aluminum.

3. The battery pack according to claim 1, wherein in the configuration (1), the configuration (2), the configuration (3), the configuration (4) and the configuration (5), the non-contact portion of the first member is located in an area relatively closer to the second contact portion than the second mounting portion of the second member in a direction intersecting the stacking direction.

4. The battery pack described in claim 1, wherein in the configuration (1), the second member includes a bent portion bent from the second contact portion along the stacking direction between the second contact portion and the second mounting portion, and at least a tip of the non-contact portion of the first member is located in a region relatively closer to the second contact portion than the bent portion of the second member.

5. The battery pack according to claim 1, wherein in the configuration (2), a tip of the non-contact portion of the first member faces and is spaced apart from the bent portion of the second member in the stacking direction.

6. The battery pack according to claim 1, wherein in the configuration (2), the second member includes two or more bent portions that are continuous with each other.

7. The battery pack according to claim 1, wherein in the configuration (3), the second member includes a bent portion bent from the second contact portion along the stacking direction between the second contact portion and the second mounting portion, and the corner portion of the first member is located in an area relatively closer to the second contact portion than the bent portion of the second member.

8. The battery pack according to claim 1, wherein in the configuration (4), a tip of the non-contact portion of the first member faces and is spaced apart from the inclined portion of the second member in the stacking direction.

9. The battery pack according to claim 1, wherein in the configuration (1), (2), (3), (4) and (5), the non-contact portion of the first member has no region that faces the second member along a direction perpendicular to the stacking direction.

10. The battery pack according to claim 1, wherein in the configuration (1), the configuration (3) and the configuration (5), the non-contact portion of the first member has an area facing the second member along a direction perpendicular to the stacking direction.

11. The battery pack described in claim 1, wherein the solid-state welded portion is formed in a rectangular shape, and the first contact portion of the first member and the second contact portion of the second member are solid-state welded in a direction intersecting the stacking direction, toward a side on which the non-contact portion of the first member is located and toward a side opposite to the longitudinal direction of the solid-state welded portion.

12. A device comprising: a plurality of batteries; and a bus bar connected to one of the batteries and another of the batteries, or connected to one of the batteries and connected to an external electrical device, wherein the bus bar comprises: a first member having electrical conductivity; and a second member having electrical conductivity, laminated and joined to the first member and made of the same material as the first member, wherein the first member comprises: a first mounting portion attached to an electrode terminal of one of the batteries or to the electrical device, a first contact portion connected to the first mounting portion and in contact with the second member in the stacking direction, and a first non-contact portion connected to the first contact portion and at least partially not in contact with the second member in the stacking direction, wherein the second member comprises: a second mounting portion attached to an electrode terminal of the other of the batteries, a second contact portion connected to the second mounting portion and in contact with the first contact portion of the first member in the stacking direction, and a second non-contact portion connected to the second contact portion and at least partially not in contact with the first contact portion of the first member in the stacking direction, the first contact portion of the first member and the second contact portion of the second member include a solid-state welded portion, the first non-contact portion of the first member is located closer to the second attachment portion of the second member than the solid-state welded portion, and the second non-contact portion of the second member is located closer to the first attachment portion of the first member than the solid-state welded portion; and the present invention includes at least one or more of the following configurations (1), (2), (3), (4), (5) and (6), and at least one or more of the following configurations (7), (8) and (9), wherein in configuration (1), at least a tip of the first non-contact portion of the first member is inclined with respect to a direction intersecting the stacking direction and is separated from the second contact portion of the second member, and in configuration (2), the first member has the solid-state welded portion formed in a location that does not overlap with the first attachment portion in the stacking direction, the second member includes a second bent portion bent from the second contact portion along the stacking direction between the second contact portion and the second attachment portion, and at least a tip of the first non-contact portion of the first member is separated from the second bent portion of the second member.a tip end of the first non-contact portion of the first member includes a corner portion that is curved or inclined facing the second member in the stacking direction, and a length of the corner portion of the first member along the stacking direction is 1 / 10 or more of a length of the first non-contact portion of the first member along the stacking direction, or 0.1 mm or more; in the configuration (4), the second member includes a second inclined portion between the second contact portion and the second mounting portion that is inclined from the second contact portion toward a direction intersecting the stacking direction, and at least the tip end of the first non-contact portion of the first member is separated from the second inclined portion of the second member; in the configuration (5), the second member includes a recess between the second contact portion and the second mounting portion that is recessed in a direction away from the first non-contact portion of the first member with respect to the stacking direction, and at least the tip end of the first non-contact portion of the first member is separated from the recess of the second member; in the configuration (6), the first non-contact portion of the first member is formed as a pair on both sides of the first contact portion of the first member, and at least a tip of the pair of first non-contact portions of the first member is separated from the second member; in the configuration (7), a tip of the second non-contact portion of the second member includes a curved or inclined corner facing the first member in the stacking direction, and a length of the corner of the second member along the stacking direction is 1 / 10 or more of a length of the second non-contact portion of the second member along the stacking direction, or 0.1 mm or more; in the configuration (8), at least a tip of the second non-contact portion of the second member is separated from the first contact portion of the first member at an incline with respect to a direction intersecting the stacking direction; and in the configuration (9), the first member includes a recess between the first contact portion and the first mounting portion that is recessed in a direction away from the second non-contact portion of the second member with respect to the stacking direction, and at least a tip of the second non-contact portion of the second member is separated from the recess of the first member.

13. The battery pack according to claim 11, wherein the first member and the second member each contain aluminum or copper.

14. The battery pack according to claim 1 or claim 12, wherein the second member includes a solid-state welded portion in which the first contact portion of the first member and the second contact portion of the second member are solid-state welded in a direction intersecting the stacking direction and including at least a side on which the first non-contact portion of the first member and the second non-contact portion of the second member are located.

15. A device comprising: a plurality of batteries; and a bus bar connected to one of the batteries and the other batteries, or connected to one of the batteries and connected to an external electrical device, wherein the bus bar comprises: a first member having electrical conductivity; and a second member having electrical conductivity, laminated and joined to the first member, and having a hardness lower than that of the first member, wherein the first member comprises: a first contact portion in contact with the second member in a stacking direction; and a non-contact portion having an annular portion that is connected to the first contact portion from the outside of the first contact portion on a plane intersecting with the stacking direction of the first contact portion and is not in contact with the second member in the stacking direction, wherein the second member comprises a second contact portion in contact with the first contact portion of the first member in the stacking direction, and the non-contact portion of the first member surrounds the second contact portion of the second member in a plane intersecting with the stacking direction in a ring shape, the first contact portion of the first member and the second contact portion of the second member include a solid-state welded portion that is annularly solid-state welded along a surface that intersects with the stacking direction and a region in which the non-contact portion of the first member is located.

16. A battery pack comprising: a plurality of stacked batteries each having an electrode terminal; and a bus bar for connecting to the electrode terminal of a first battery, the electrode terminal of a second battery electrically connected to the first battery, or an external electrical device, wherein the bus bar comprises: a first member having electrical conductivity; a second member having electrical conductivity; an overlapping portion in which the first member and a portion of the second member are overlapped; and a solid-state welded portion formed in the overlapping portion; the first member comprises: a first mounting portion having a first mounting surface connected to either the first battery or the electrical device and a first back surface located on the opposite side to the first mounting surface; a first overlapping portion constituting the overlapping portion; and the solid-state welded portion formed in the first overlapping portion and positioned away from the first back surface; and the second member comprises: a second mounting portion having a second mounting surface connected to either the second battery or the electrical device when the first member is connected to the first battery, or to the first battery when the first member is connected to the electrical device, and a second back surface located opposite the second mounting surface; a second overlapping portion constituting the overlapping portion; and the solid-state welded portion formed in the second overlapping portion and positioned away from the second back surface, wherein the first overlapping portion has, in a direction in which the first overlapping portion and the second overlapping portion are overlapped, a non-contact portion positioned away from the second overlapping portion, and a tip formed on the non-contact portion.

17. The battery pack described in claim 16, wherein the first member is a first metal plate made of a first metal material, and the second member is a second metal plate made of a second metal material having a lower hardness than the first metal plate.

18. The battery pack according to claim 17, wherein the first overlapping portion is positioned farther from the battery than the second overlapping portion, or the second overlapping portion is positioned farther from the battery than the first overlapping portion.

19. The battery pack described in claim 17, wherein, in the overlapping direction, the first overlapping portion has a first non-contact portion located away from the second contact surface, and the tip has a first tip formed on the first non-contact portion, and the second overlapping portion has, in the overlapping direction, a second non-contact portion located away from the first connection surface and a second tip formed on the second non-contact portion, and, in the overlapping direction, the first overlapping portion has the first tip formed such that the length from the second contact surface to the first tip is longer than the length from the first contact surface to the second tip.

20. (1) The non-contact portion of the first member has a first portion between the solid-state welded portion and the tip, and a second portion closer to the tip than the first portion, and the second portion has a distance between the first overlapping portion and the second overlapping portion in the overlapping direction that is larger than the distance between the first portion and the second overlapping portion; (2) The first overlapping portion has a first contact surface that includes the solid-state welded portion and is in contact with the second overlapping portion, and the second overlapping portion has a second contact surface that includes the solid-state welded portion and is in contact with the first overlapping portion; and the second overlapping portion of the second member has a bent portion between the solid-state welded portion and the tip that is bent in a direction away from the first contact surface in the overlapping direction; (3) The tip of the first overlapping portion has a first corner portion that is arc-shaped or inclined toward the second overlapping portion, In the case where the first mounting portion has a second corner portion having an arc shape or an inclined shape formed on the side of the tip opposite to the second overlapping portion, or a third corner portion having an arc shape or an inclined shape formed on the tip of the first mounting portion, the length of the first corner portion is longer than the length of the second corner portion or the third corner portion in the overlapping direction; (4) the second overlapping portion has a recess or an inclined portion recessed in a direction away from the first overlapping portion, the recess or inclined portion is arranged overlapping with the tip in the overlapping direction, and the first overlapping portion has the tip arranged in a non-contact state with the recess or inclined portion; (5) the first overlapping portion has a first contact surface including the solid-state welded portion and in contact with the second overlapping portion, the second overlapping portion has a second contact surface including the solid-state welded portion and in contact with the first overlapping portion, and the first overlapping portion has, in the overlapping direction, an inclined portion inclined toward a side away from the second contact surface at a portion on the tip side of the solid-state welded portion, 20. The battery pack according to claim 16, wherein the inclined portion has the non-contact portion located away from the second contact surface, and the tip is formed on the non-contact portion.

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