Busbars and battery modules

Abstract

One embodiment provides a busbar which electrically connects two electrode terminals disposed to be spaced apart from each other. The busbar comprises a layered plate body, a first joint part, and a second joint part, wherein a plurality of conductive plates are stacked in the layered plate body. The first joint part is formed in an end section on one side of the layered plate body in the length direction of the layered plate body, the length direction crossing the stacked direction of the plurality of conductive plates, and is joined to a separate first conductive member different from the layered plate body. The second joint part is formed in an end section on the opposite side from the first joint part in the length direction of the layered plate body, and is joined to the layered plate body and a separate second conductive member different from the first conductive member.

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a bus bar and a battery module. [Background technology]

[0002] In a battery module or the like including a plurality of batteries (single cells), an electrode terminal of one battery is electrically connected to an electrode terminal of another battery via a bus bar. In this case, the bus bar is connected to each of two electrode terminals (a first electrode terminal and a second electrode terminal) by joining using laser welding or the like. In recent years, battery modules formed from a plurality of batteries are required to have higher output. A battery module with high output performance is required to appropriately suppress temperature increases in the bus bar electrically connecting the two electrode terminals, even when a large current flows. For this reason, the bus bar is required to have an appropriate cross-sectional area perpendicular or substantially perpendicular to the extension direction of the electrical path, thereby appropriately suppressing increases in electrical resistance in the bus bar. Furthermore, a battery module or the like is required to appropriately relieve stress applied from the bus bar to the electrode terminals to which the bus bar is connected. Furthermore, each of the batteries (single cells) forming the battery module is required to effectively prevent deterioration in the airtightness of the internal cavity due to stress from the bus bar to the electrode terminals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2009-87761 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a bus bar that ensures an appropriate cross-sectional area perpendicular or nearly perpendicular to the extension direction of the electrical path and that appropriately relieves stress applied to the electrode terminals, and a battery module that includes the bus bar. [Means for solving the problem]

[0005] According to an embodiment, there is provided a bus bar that electrically connects a first electrode terminal and a second electrode terminal that are spaced apart from each other. The bus bar includes a stacked plate body. The stacked plate body has a first end portion at one end in the arrangement direction of the first electrode terminal and the second electrode terminal. formed , a first connector plate joined to the first electrode terminal; The first bond to be bonded Department, and At the end opposite the first joint in the alignment direction formed , a second connector plate joined to the second electrode terminal; The stacked plate body is formed by stacking a plurality of conductive plates. The plate stack has a first plate abutting portion at an end where the first joint in the arrangement direction is located, where adjacent conductive plates in the stacking direction abut, and a second plate abutting portion at an end where the second joint in the arrangement direction is located, where adjacent conductive plates in the stacking direction abut. The plate stack has a plate spacing portion between the first plate abutting portion and the second plate abutting portion, where adjacent conductive plates in the stacking direction are spaced apart. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing an example of a single battery according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an example of a battery module according to an embodiment. [Figure 3] FIG. 3 is a schematic view showing the bus bar according to the first embodiment as viewed from one side in a first direction. [Figure 4] FIG. 4 is a schematic diagram showing the bus bar according to the first embodiment, two electrode terminals to which the bus bar is connected, and the configuration in the vicinity thereof, in a cross section perpendicular or substantially perpendicular to the third direction. [Figure 5] FIG. 5 is a schematic diagram illustrating a bus bar according to a first modified example of the first embodiment, two electrode terminals to which the bus bar is connected, and the configuration in the vicinity thereof, in a cross section perpendicular or substantially perpendicular to a third direction. [Figure 6]FIG. 6 is a schematic diagram illustrating a bus bar according to a second modified example of the first embodiment, two electrode terminals to which the bus bar is connected, and the configuration in the vicinity thereof, in a cross section perpendicular or substantially perpendicular to a third direction. [Figure 7] FIG. 7 is a schematic diagram showing a bus bar according to a third modified example of the first embodiment, two electrode terminals to which the bus bar is connected, and the configuration in the vicinity thereof, in a cross section perpendicular or substantially perpendicular to a third direction. [Figure 8] FIG. 8 is a schematic view showing a bus bar according to the second embodiment as viewed from one side in the first direction. [Figure 9] FIG. 9 is a schematic diagram showing a bus bar according to the second embodiment, two electrode terminals to which the bus bar is connected, and the configuration in the vicinity thereof, when the bus bar is viewed from one side in a third direction. [Figure 10] FIG. 10 is a schematic diagram illustrating a bus bar according to a modification of the second embodiment, two electrode terminals to which the bus bar is connected, and the configuration of the vicinity thereof, when the bus bar is viewed from one side in a third direction. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments will be described with reference to the drawings. A battery module according to the embodiment includes a plurality of batteries. The plurality of batteries includes a first battery and a second battery. The first battery includes a first electrode terminal, and the second battery includes a second electrode terminal. In the battery module, a bus bar electrically connects the first terminal of the first battery and the second terminal of the second battery. The bus bar is connected to each of the first electrode terminal and the second electrode terminal by joining them by laser welding or the like.

[0008] [battery] First, a battery unit provided in a battery module will be described. FIG. 1 shows an example of a battery unit 1. The battery 1, which is a single cell, includes an electrode group 2 and an outer container 3 in which the electrode group 2 is housed. In the example shown in FIG. 1, etc., the outer container 3 is made of a metal such as aluminum, an aluminum alloy, iron, or stainless steel. The outer container 3 includes a container body 5 and a lid 6. The battery 1 and the outer container 3 have defined depth directions (directions indicated by arrows X1 and X2), lateral directions (directions indicated by arrows Y1 and Y2) that intersect (orthogonal or substantially perpendicular to) the depth direction, and height directions (directions indicated by arrows Z1 and Z2) that intersect (orthogonal or substantially perpendicular to) both the depth and lateral directions. In the example shown in FIG. 1, etc., the depth dimensions of the battery 1 and the outer container 3 are smaller than the lateral and height dimensions, respectively.

[0009] The container body 5 has a bottom wall 7 and a peripheral wall 8. An internal cavity 10 in which the electrode group 2 is housed is defined by the bottom wall 7 and the peripheral wall 8. In the battery 1, the internal cavity 10 opens toward the opposite side in the height direction from the side on which the bottom wall 7 is located. The peripheral wall 8 surrounds the internal cavity 10 around the entire circumferential direction. The lid 6 is attached to the container body 5 by welding or the like at the opening of the internal cavity 10. Therefore, the lid 6 is attached to the peripheral wall 8 at the end opposite the bottom wall 7. The lid 6 and the bottom wall 7 face each other in the height direction, sandwiching the internal cavity 10 therebetween. The internal cavity 10 is sealed and airtight from the outside of the outer container 3.

[0010] The electrode group 2 includes a positive electrode and a negative electrode (neither of which is shown). A separator (not shown) is interposed between the positive electrode and the negative electrode in the electrode group 2. The separator is made of an electrically insulating material and electrically insulates the positive electrode from the negative electrode.

[0011] The positive electrode comprises a positive electrode current collector such as a positive electrode current collector foil, and a positive electrode active material-containing layer supported on the surface of the positive electrode current collector. The positive electrode current collector is, but is not limited to, for example, an aluminum foil or an aluminum alloy foil, and has a thickness of approximately 5 μm to 20 μm. The positive electrode active material-containing layer comprises a positive electrode active material and may optionally contain a binder and a conductive agent. Examples of positive electrode active materials include, but are not limited to, oxides, sulfides, and polymers capable of absorbing and releasing lithium ions. The positive electrode current collector comprises a positive electrode current collecting tab as a portion not supported by the positive electrode active material-containing layer.

[0012] The negative electrode comprises a negative electrode current collector such as a negative electrode current collector foil, and a negative electrode active material-containing layer (not shown) supported on the surface of the negative electrode current collector. The negative electrode current collector is, but is not limited to, for example, aluminum foil, aluminum alloy foil, or copper foil, and has a thickness of approximately 5 μm to 20 μm. The negative electrode active material-containing layer comprises a negative electrode active material and may optionally contain a binder and a conductive agent. The negative electrode active material is, but is not limited to, metal oxides, metal sulfides, metal nitrides, and carbon materials capable of absorbing and releasing lithium ions. The negative electrode current collector comprises a negative electrode current collector tab as a portion not supported by the negative electrode active material-containing layer.

[0013] In the electrode group 2, a pair of current collecting tabs is formed by a positive electrode current collecting tab and a negative electrode current collecting tab. In the electrode group 2, a pair of current collecting tabs protrudes. In one example, in the electrode group 2, the positive electrode current collecting tab protrudes to one side in the lateral direction of the battery 1, and the negative electrode current collecting tab protrudes to the side opposite to the side from which the positive electrode current collecting tab protrudes in the lateral direction of the battery 1. In another example, in the electrode group 2, each of the pair of current collecting tabs protrudes toward the side where the lid 6 is located in the height direction of the battery 1. In this case, the pair of current collecting tabs are positioned apart from each other in the lateral direction of the battery 1.

[0014] In addition, in the internal cavity 10, the electrode group 2 is retained (impregnated) with an electrolytic solution (not shown). The electrolytic solution may be a non-aqueous electrolytic solution in which an electrolyte is dissolved in an organic solvent, or may be an aqueous electrolytic solution such as an aqueous solution. Instead of the electrolytic solution, a gel electrolyte or a solid electrolyte may be used. When a solid electrolyte is used as the electrolyte, the solid electrolyte may be interposed between the positive electrode and the negative electrode in the electrode group, instead of a separator. In this case, the solid electrolyte electrically insulates the positive electrode from the negative electrode.

[0015] In the battery 1, a pair of electrode terminals 11 are attached to the outer surface (top surface) of the lid 6 of the outer container 3. The electrode terminals 11 are made of a conductive material such as metal. One of the electrode terminals 11 is a positive terminal of the battery 1, and the other electrode terminal 11 is a negative terminal of the battery 1. Each of the electrode terminals 11 penetrates the lid 6 through a corresponding through-hole (not shown) and is inserted into the internal cavity 10. An insulating member 12 and an insulating gasket (not shown) are provided between each of the electrode terminals 11 and the lid 6. The insulating member 12 and the insulating gasket prevent each of the electrode terminals 11 from contacting the lid 6 and electrically insulate the electrode terminals 11 from the outer container 3, including the lid 6. Furthermore, at the portions where each of the electrode terminals 11 penetrates the lid 6, the insulating gasket ensures airtightness between the lid 6 and the electrode terminals 11. Therefore, even if through-holes for passing each of the electrode terminals 11 through the lid 6 are formed in the lid 6, the internal cavity 10 is properly sealed from the outside of the outer container 3.

[0016] The positive electrode current collecting tab of the electrode group 2 is electrically connected to a positive electrode terminal, which is one of the corresponding electrode terminals 11, via one or more leads (positive electrode side leads). Furthermore, the negative electrode current collecting tab of the electrode group 2 is electrically connected to a negative electrode terminal, which is one of the corresponding electrode terminals 11, via one or more leads (negative electrode side leads). In each of the electrode terminals 11, the portion inserted into the internal cavity 10 is connected to the corresponding lead. Each of the leads is made of a conductive material such as metal. Furthermore, in the internal cavity 10 of the outer container 3, each of the pair of current collecting tabs and leads is electrically insulated from the outer container 3 (container body 5 and lid 6) by one or more insulating members (not shown).

[0017] The positive electrode terminal and the lead (positive electrode lead) electrically connecting the positive electrode current collector tab and the positive electrode terminal are preferably formed from the same material as the positive electrode current collector. This reduces the contact resistance at the connection portion of the positive electrode current collector tab to the lead and the contact resistance at the connection portion of the positive electrode terminal to the lead in the electrical path between the positive electrode current collector tab and the positive electrode terminal. Similarly, the negative electrode terminal and the lead (negative electrode lead) electrically connecting the negative electrode current collector tab and the negative electrode terminal are preferably formed from the same material as the negative electrode current collector. This reduces the contact resistance at the connection portion of the negative electrode current collector tab to the lead and the contact resistance at the connection portion of the negative electrode terminal to the lead in the electrical path between the negative electrode current collector tab and the negative electrode terminal. For example, when the negative electrode current collector is aluminum foil, the negative electrode lead and the negative electrode terminal are preferably formed from aluminum. When the negative electrode current collector is copper foil, the negative electrode lead and the negative electrode terminal are preferably formed from copper.

[0018] 1, a gas release valve 13 and a liquid filling port are formed in the lid 6. A sealing plate 15 that closes the liquid filling port is welded to the outer surface of the lid 6. The gas release valve 13, the liquid filling port, etc. do not necessarily have to be provided in the battery.

[0019] Furthermore, the configuration of the battery (single cell) is not limited to the example shown in Fig. 1. In one example, the exterior of the battery may be formed from a laminate film instead of the exterior container 3. In this case, in the exterior of the battery, a metal layer is sandwiched between two insulating layers that have electrical insulation properties, and the outer surface of the exterior is formed by one of the two insulating layers. An electrode group is then housed inside the exterior formed from the laminate film.

[0020] [Battery module] Next, a battery module including a plurality of batteries (single cells) as described above will be described. FIG. 2 shows an example of a battery module 20. The battery module 20 includes batteries 1A and 1B. The batteries 1A and 1B have the same configuration as the battery 1 shown in FIG. 1. In the battery module 20, the battery (first battery) 1A includes an electrode terminal (first electrode terminal) 11A as one of a pair of electrode terminals 11, and the battery (second battery) 1B includes an electrode terminal (second electrode terminal) 11B as one of the pair of electrode terminals 11. The battery module 20 also includes a bus bar 21, which electrically connects the electrode terminal (first electrode terminal) 11A of the battery 1A to the electrode terminal (second electrode terminal) 11B of the battery 1B. The bus bar 21 is connected to each of the electrode terminals 11A and 11B by laser welding or the like.

[0021] In the example shown in Figure 2, one of the electrode terminals 11A and 11B of battery 1A serves as a positive terminal, and the other of the electrode terminals 11A and 11B serves as a negative terminal. Therefore, in the example shown in Figure 2, the batteries 1A and 1B are electrically connected in series by the bus bar 21. In another example, two bus bars similar to the bus bar 21 may be used to electrically connect the two batteries in parallel. In this case, one of the two bus bars electrically connects the positive terminals of the two batteries. The other of the two bus bars electrically connects the negative terminals of the two batteries.

[0022] [Busbar] A bus bar according to an embodiment will be described below. As described above, the bus bar electrically connects two electrode terminals. For example, in a battery module including a first battery and a second battery, the bus bar electrically connects a first electrode terminal of a first battery and a second electrode terminal of a second battery. The bus bar is made of a conductive material such as metal.

[0023] (First embodiment) First, a busbar 21 according to a first embodiment will be described. The busbar 21 of this embodiment electrically connects two electrode terminals 11A and 11B in the example battery module 20 shown in FIG. 2. FIG. 3 shows the busbar 21 of this embodiment, and FIG. 4 shows the busbar 21 of this embodiment, the two electrode terminals 11A and 11B to which the busbar 21 is connected (joined), and the configuration of the vicinity thereof. As shown in FIGS. 3 and 4, the busbar 21 defines a first direction (the direction indicated by arrows Z3 and Z4), a second direction (the direction indicated by arrows Y3 and Y4) that intersects (is perpendicular or substantially perpendicular to) the first direction, and a third direction (the direction indicated by arrows X3 and X4) that intersects (is perpendicular or substantially perpendicular to) both the first and second directions. 3 shows busbar 21 as viewed from one side in a first direction, and FIG. 4 shows busbar 21 in a cross section perpendicular or substantially perpendicular to a third direction.

[0024] In this embodiment, bus bar 21 includes a pair of connector plates 22A, 22B and a stacked plate body 23. Each of connector plates 22A, 22B has a plate length direction, a plate width direction that intersects (is perpendicular or substantially perpendicular to) the plate length direction, and a plate thickness direction that intersects (is perpendicular or substantially perpendicular to) both the plate length direction and the plate width direction. Each of connector plates 22A, 22B has a plate thickness direction that coincides or substantially coincides with a first direction of bus bar 21, and a plate length direction that coincides or substantially coincides with a second direction of bus bar 21. Each of connector plates 22A, 22B has a plate width direction that coincides or substantially coincides with a third direction of bus bar 21.

[0025] The connector plate (first connector plate) 22A is a conductive member (first conductive member) made of a conductive material and is joined to the electrode terminal (first electrode terminal) 11A of the battery 1A by ultrasonic welding or the like. The connector plate 22A is joined (connected) to the electrode terminal 11A with the electrode terminal 11A abutting against it from one side (arrow Z3 side) of the bus bar 21 in the first direction. In the example shown in Figures 2 and 4, the connector plate 22A is joined to the electrode terminal 11A with the electrode terminal 11A abutting against it from the side facing the outer surface of the lid 6 of the battery 1A. As shown in the example shown in Figure 3, the connector plate 22A has a through-hole 25A that penetrates the connector plate 22A in the plate thickness direction. The connector plate 22A is joined to the electrode terminal 11A on the surface facing the electrode terminal 11A (battery 1A) in the plate thickness direction (first direction of the bus bar 21) and in the area around the through hole 25A.

[0026] The connector plate (second connector plate) 22B is a conductive member (second conductive member) made of a conductive material and is joined to the electrode terminal (second electrode terminal) 11B of the battery 1B by ultrasonic welding or the like. The electrode terminal 11B abuts against the connector plate 22B from the side (arrow Z3 side) where the electrode terminal 11A abuts against the connector plate 22A in the first direction of the bus bar 21. The connector plate 22B is joined (connected) to the electrode terminal 11B in the aforementioned abutting state. In examples such as FIGS. 2 and 4, the connector plate 22B is joined to the electrode terminal 11B in a state where it abuts against the electrode terminal 11B from the side facing the outer surface of the lid 6 of the battery 1B. As shown in an example in FIG. 3, the connector plate 22B has a through-hole 25B penetrating the connector plate 22B in the plate thickness direction. The connector plate 22B is joined to the electrode terminal 11B on the surface facing the side where the electrode terminal 11B (battery 1B) is located in the plate thickness direction (first direction of the bus bar 21), and in the area around the through hole 25B.

[0027] In the bus bar 21, the connector plates 22A, 22B are connected by a stacked plate body 23. The stacked plate body 23 includes a plurality of conductive plates 26; in one example, such as FIG. 4, the stacked plate body 23 includes four conductive plates 26. Each of the plurality of conductive plates 26 is formed from a conductive material and is conductive. In the stacked plate body 23, the plurality of conductive plates 26 are stacked on top of each other. Each of the plurality of conductive plates 26 has a plate length direction, a plate width direction that intersects (orthogonal or approximately orthogonal to) the plate length direction, and a plate thickness direction that intersects (orthogonal or approximately orthogonal to) both the plate length direction and the plate width direction. In the stacked plate body 23, the plurality of conductive plates 26 are stacked with the plate thickness direction of each conductive plate 26 coinciding or approximately coinciding with the stacking direction.

[0028] In the plate stack 23, the stacking direction of the multiple conductive plates 26 is defined as the thickness direction. The plate stack 23 also has a length direction that intersects (orthogonal or approximately orthogonal to) the stacking direction and a width direction that intersects (orthogonal or approximately orthogonal to) both the stacking direction and the length direction. The length direction of the plate stack 23 coincides or approximately coincides with the plate length direction of each of the conductive plates 26. The width direction of the plate stack 23 coincides or approximately coincides with the plate width direction of each of the conductive plates 26 and also coincides or approximately coincides with the third direction of the bus bar 21. Of the multiple conductive plates 26 forming the plate stack 23, the conductive plate 26A is located closest to the electrode terminals 11A and 11B, and the conductive plate 26B is located most distal to the electrode terminals 11A and 11B.

[0029] Each of the plurality of conductive plates 26 has an edge surface E1 that forms one end in the plate length direction, and an edge surface E2 that forms the end opposite the edge surface E1 in the plate length direction. The stacked plate body 23 also has an end S1 on one side in the length direction, and an end S2 opposite the end S1 in the length direction. In one example, such as FIG. 4 , the edge surfaces E1 of the plurality of conductive plates 26 are not or barely offset from one another in the length direction of the stacked plate body 23. Therefore, in one example, such as FIG. 4 , the edge surfaces E1 of all of the conductive plates 26 form the edge S1 of the stacked plate body 23. Also, in one example, such as FIG. 4 , the edge surfaces E2 of the plurality of conductive plates 26 are not or barely offset from one another in the length direction of the stacked plate body 23. Therefore, in one example, such as FIG. 4 , the edge surfaces E2 of all of the conductive plates 26 form the edge S2 of the stacked plate body 23.

[0030] In one example, the edge surfaces E1 of one or more conductive plates 26 are offset from the edge surfaces E1 of the other conductive plates 26 in the length direction of the stacked plate body 23, and the edge S1 of the stacked plate body 23 is formed by only the edge surfaces E1 of some of all the conductive plates 26. In this case, the edge surfaces E1 of the remaining conductive plates 26 are offset from the edge S1 of the stacked plate body 23 toward the edge S2. Similarly, the edge surfaces E2 of one or more conductive plates 26 are offset from the edge surfaces E2 of the other conductive plates 26 in the length direction of the stacked plate body 23, and the edge S2 of the stacked plate body 23 is formed by only the edge surfaces E2 of some of all the conductive plates 26. In this case, the edge surfaces E2 of the remaining conductive plates 26 are offset from the edge S2 of the stacked plate body 23 toward the edge S1.

[0031] Furthermore, bending positions B1 and B2 are formed in the plate stack 23 between the ends S1 and S2 in the longitudinal direction. At the bending position B1, a portion of each of the plurality of conductive plates 26 adjacent to the opposite side of the end S1 relative to the bending position B1 bends toward the portion between the end S1 and the bending position B1. At the bending position B1, a portion of each of the plurality of conductive plates 26 adjacent to the opposite side of the end S1 relative to the bending position B1 bends toward the side away from the electrode terminals 11A and 11B (distal to the electrode terminals 11A and 11B) in the first direction of the bus bar 21. At the bending position B2, a portion of each of the plurality of conductive plates 26 adjacent to the opposite side of the end S2 relative to the bending position B2 bends toward the portion between the end S2 and the bending position B2. At the bending position B2, a portion of each of the plurality of conductive plates 26 adjacent to the opposite side of the end S2 relative to the bending position B2 bends toward the side away from the electrode terminals 11A and 11B (distal to the electrode terminals 11A and 11B) in the first direction of the bus bar 21.

[0032] In the plate stack 23, the portion between the bending positions B1 and B2 in the longitudinal direction is formed in a convex shape that protrudes from the electrode terminals 11A and 11B in the first direction of the bus bar 21. Therefore, in each of the conductive plates 26 of the plate stack 23, the portion between the bending positions B1 and B2 in the longitudinal direction protrudes away from the electrode terminals 11A and 11B relative to the portion between the end S1 and the bending position B1 and the portion between the end S2 and the bending position B2. Therefore, in the plate stack 23, a convex apex 28 is formed between the bending positions B1 and B2 in the longitudinal direction, and the apex 28 forms a protruding end of the convex shape between the bending positions B1 and B2.

[0033] 4 and other examples, each of the plurality of conductive plates 26 is formed in a curved shape in the convex portion between bending positions B1 and B2 in the longitudinal direction of the plate stack 23. In each curved shape of the conductive plates 26 formed between bending positions B1 and B2, the side on which the electrode terminals 11A and 11B are located in the first direction is the inner side of the curve, and the side away from the electrode terminals 11A and 11B in the first direction is the outer side of the curve. In addition, in the convex portion between bending positions B1 and B2 in the longitudinal direction of the plate stack 23, the surface of each of the plurality of conductive plates 26 facing the stacking direction is formed in a curved shape.

[0034] In one example, such as FIG. 4 , in a cross section perpendicular or substantially perpendicular to the third direction (the width direction of the plate stack 23), the cross section of each of the conductive plates 26 at the convex portion between the bending positions B1 and B2 is arc-shaped or substantially arc-shaped. The center of the arc-shaped or substantially arc-shaped cross section formed by each of the conductive plates 26 at the convex portion is located on the side of the plate stack 23 where the electrode terminals 11A and 11B are located in the first direction. Note that, in one example, in a cross section perpendicular or substantially perpendicular to the third direction (the width direction of the plate stack 23), the cross section of each of the plurality of conductive plates 26 at the convex portion may be U-shaped or substantially U-shaped, for example. Furthermore, in one example, such as FIG. 4 , each of the conductive plates 26 abuts against the adjacent conductive plate 26 in the stacking direction over the entire length or substantially the entire length from the edge surface E1 to the edge surface E2.

[0035] In the plate stack 23, a joint (first joint) 27A is formed at one end in the longitudinal direction, i.e., in the vicinity of the end S1 in the longitudinal direction, to be joined to the connector plate 22A, which is a conductive member (first conductive member). The joint 27A of the plate stack 23 is joined to the connector plate 22A by ultrasonic welding or the like. In the plate stack 23, the joint 27A is formed in a portion between the end S1 and the bending position B1. In addition, in an example such as FIG. 4 , the joint 27A is formed in the conductive plate 26A, which is located closest to the electrode terminals 11A and 11B among the multiple conductive plates 26. The joint 27A is formed in the conductive plate 26A on the surface facing the side where the electrode terminals 11A and 11B are located in the first direction. Therefore, in the example shown in Figure 4, the joint portion 27A of the stacked plate body 23 (conductive plate 26A) is joined to the connector plate 22A with the stacked plate body 23 abutting against the connector plate 22A from the side opposite to the side on which the electrode terminals 11A, 11B are located in the first direction.

[0036] In the plate stack 23, a joint (second joint) 27B is formed at an end opposite to the joint 27A in the longitudinal direction, i.e., in the vicinity of the end S2 in the longitudinal direction, to be joined to the connector plate 22B, which is a conductive member (second conductive member). The joint 27B of the plate stack 23 is joined to the connector plate 22B by ultrasonic welding or the like. In the plate stack 23, the joint 27B is formed in a portion between the end S2 and the bending position B2. In addition, in an example such as FIG. 4 , the joint 27B is formed in the conductive plate 26A, which is located closest to the electrode terminals 11A and 11B among the multiple conductive plates 26. The joint 27B is formed in the conductive plate 26A on the surface facing the side where the electrode terminals 11A and 11B are located in the first direction. Therefore, in the example shown in Figure 4, the joint portion 27B of the stacked plate body 23 (conductive plate 26A) is joined to the connector plate 22B in a state in which the stacked plate body 23 abuts against the connector plate 22B from the side opposite to the side on which the electrode terminals 11A, 11B are located in the first direction.

[0037] In the plate stack 23, the plurality of conductive plates 26 are joined to one another at joints 27A and nearby areas in the longitudinal direction, such as the area between end S1 and bending position B1. In addition, in the plate stack 23, the plurality of conductive plates 26 are joined to one another at joints 27B and nearby areas in the longitudinal direction, such as the area between end S2 and bending position B2. However, in the plate stack 23, except for joints 27A and 27B and nearby areas, the conductive plates 26 are not joined to the other conductive plates 26. For example, in the area between bending positions B1 and B2 in the longitudinal direction of the plate stack 23, the conductive plates 26 are not joined to the other conductive plates 26. Therefore, in the plate stack 23, non-jointed portions, in which the conductive plates 26 are not joined to the other conductive plates 26, are formed over most of the longitudinal direction.

[0038] In one example, a joint (first joint) 27A may be formed on the conductive plate 26B, which is located most distally from the electrode terminals 11A and 11B among the multiple conductive plates 26. In this case, the joint 27A of the conductive plate 23 is joined to the connector plate (first connector plate) 22A with the conductive plate 23 (conductive plate 26B) abutting against the connector plate 22A from the side where the electrode terminals 11A and 11B are located in the first direction. Similarly, a joint (second joint) 27B may be formed on the conductive plate 26B, which is located most distally from the electrode terminals 11A and 11B among the multiple conductive plates 26. In this case, the joint 27B of the conductive plate 23 is joined to the connector plate (second connector plate) 22B with the conductive plate 23 (conductive plate 26B) abutting against the connector plate 22B from the side where the electrode terminals 11A and 11B are located in the first direction.

[0039] Each of the plurality of conductive plates 26 forming the stacked plate body 23 has a plate thickness T0. The plate thicknesses T0 of the plurality of conductive plates 26 are the same or approximately the same as each other. Furthermore, each of the connector plates 22A and 22B has a plate thickness T1. The plate thicknesses T1 of the connector plates 22A and 22B are the same or approximately the same as each other. The plate thickness T0 of each of the plurality of conductive plates 26 is thinner than the plate thickness T1 of the connector plates 22A and 22B. Furthermore, in one example, the total value of the plate thicknesses T0 of the plurality (all) of conductive plates 26 is the same or approximately the same as the plate thickness T1 of each of the connector plates 22A and 22B. Here, if the number of conductive plates 26 forming the stacked plate body 23 is n (n is an integer greater than or equal to 2), the total value of the plate thicknesses T0 of all conductive plates 26 is expressed as the value (n × T0). In one example, the plate width W of each of the plurality of conductive plates 26 is the same or approximately the same size (width) as the plate width of each of the connector plates 22A, 22B.

[0040] Furthermore, the connector plate (first connector plate) 22A is preferably formed from the same material as the electrode terminal (first electrode terminal) 11A, and the connector plate (second connector plate) 22B is preferably formed from the same material as the electrode terminal (second electrode terminal) 11B. Each of the plurality of conductive plates 26 is preferably formed from a material having higher thermal conductivity and electrical conductivity than at least one of the connector plates 22A and 22B, and more preferably from a material having higher thermal conductivity than both of the connector plates 22A and 22B. In one example, each of the electrode terminals 11A and 11B is formed from aluminum, and each of the connector plates 22A and 22B is formed from aluminum. Each of the conductive plates 26 is formed from copper, which has higher thermal conductivity (thermal conductivity) and electrical conductivity (electrical conductivity) than aluminum. In another example, each of the electrode terminal 11A and the connector plate 22A is formed from aluminum, and each of the electrode terminal 11B and the connector plate 22B is formed from copper. Each of the conductive plates 26 is made of silver, which has higher thermal and electrical conductivity than aluminum and copper.

[0041] In this embodiment, a plurality of conductive plates 26 are stacked in the stacked plate body 23 of the bus bar 21. The stacked plate body 23 is joined to a connector plate 22A, which is a conductive member separate from the stacked plate body 23, at a joint 27A formed at one end in the longitudinal direction, and is joined to a connector plate 22B, which is a conductive member separate from the stacked plate body 23 and the connector plate 22A, at a joint 27B formed at the end opposite the joint 27A in the longitudinal direction. In the stacked plate body 23, the thickness T0 of each of the plurality of conductive plates 26 is thin, but the sum of the thicknesses T0 of the plurality of conductive plates 26 (n × T0) is a certain thickness (size). Therefore, in the stacked plate body 23, the cross-sectional area of ​​each of the plurality of conductive plates 26 (the cross-sectional area of ​​each individual conductive plate 26) is small, but the cross-sectional area of ​​the entire stacked plate body 23, which is the sum of the cross-sectional areas of the plurality of conductive plates 26, is ensured to be a certain size.

[0042] Therefore, in the busbar 21 of this embodiment, even if a stacked plate body 23 is provided in which a plurality of conductive plates 26 are stacked, the cross-sectional area of ​​the entire stacked plate body 23 perpendicular or substantially perpendicular to the extension direction of the electrical paths is ensured to be an appropriate size. Therefore, the cross-sectional area of ​​the busbar 21 perpendicular or substantially perpendicular to the extension direction of the electrical paths is ensured to be an appropriate size, and an increase in electrical resistance in the busbar 21 is appropriately suppressed. As a result, even if a large current flows through the busbar 21 that electrically connects the electrode terminals 11A, 11B, an increase in temperature in the busbar 21 is appropriately suppressed. By allowing a large current to flow through the busbar 21, it is possible to achieve high output from the battery module 20 including the batteries 1A, 1B.

[0043] Furthermore, stress acts on each of electrode terminals 11A, 11B to which bus bar 21 is joined (connected) from bus bar 21. Stress acts on electrode terminals 11A, 11B in the second direction of bus bar 21. As described above, bus bar 21 of the present embodiment includes stacked plate body 23 in which a plurality of conductive plates 26 are stacked. Therefore, the stress applied to each of electrode terminals 11A, 11B is reduced compared to when stacked plate body 23 is replaced with a single plate member whose cross-sectional area is the same or approximately the same as the total cross-sectional area of ​​the plurality of conductive plates 26 (the cross-sectional area of ​​the entire stacked plate body 23).

[0044] Here, the plate stack 23 includes n (n is an integer greater than or equal to 2) stacked conductive plates 26, each having a thickness T0 and a width W. In the plate stack 23 of this embodiment, as described above, the conductive plates 26 are not joined to each other over most of the length. Therefore, the plate stack 23 can essentially be considered a so-called stacked beam. The area moment of inertia I0 of the plate stack 23 can be calculated in the same way as the area moment of inertia of a stacked beam, as shown in Equation (1). As a comparative example, the plate stack 23 is replaced by a single plate member whose thickness is the same as the sum (n × T0) of the thicknesses T0 of the n conductive plates 26 and whose width W is the same as that of the conductive plate 26. In this comparative example, the area moment of inertia I1 of the single plate member is calculated as shown in Equation (2).

[0045] I0=n×((W×T0 3 ) / 12) (1) I1=(W×(n×T0) 3 ) / 12=n 3 ×((W×T0 3 ) / 12) (2)

[0046] As shown in equations (1) and (2), the second moment of area I0 of the stacked plate body 23 is 1 / n times the second moment of area I1 of a single plate member having the same cross-sectional area as the stacked plate body 23. 2Therefore, by providing the plate stack 23 on the bus bar 21, the moment of inertia of the plate stack 23 is reduced, and the stress applied from the bus bar 21 to each of the electrode terminals 11A and 11B is appropriately alleviated. By alleviating the stress applied to the electrode terminal 11A, the stress applied to the insulating gasket and other components disposed near the electrode terminal 11A in the battery 1A is also alleviated. By appropriately alleviating the stress on the insulating gasket and other components in the battery 1A, a decrease in the airtightness of the internal cavity 10 due to the stress from the bus bar 21 to the electrode terminal 11A is effectively prevented. Similarly, by alleviating the stress applied to the electrode terminal 11A in the battery 1B, a decrease in the airtightness of the internal cavity 10 due to the stress from the bus bar 21 to the electrode terminal 11B is effectively prevented.

[0047] As described above, in the busbar 21 of this embodiment, the cross-sectional area perpendicular or substantially perpendicular to the extension direction of the electrical path is ensured to be of an appropriate size, and the stress applied from the busbar 21 to each of the electrode terminals 11A, 11B is appropriately alleviated. Furthermore, in the busbar 21 of this embodiment, the plate stack 23 is formed with the bent positions B1, B2 described above, and the portion between the bent positions B1, B2 in the longitudinal direction is formed with a convex shape. By forming the convex shape (bend structure) described above in the plate stack 23, the stress applied from the busbar 21 to each of the electrode terminals 11A, 11B is further alleviated.

[0048] Furthermore, in this embodiment, by forming connector plate 22A from the same material as electrode terminal 11A, it is possible to effectively prevent voids from being formed at the joint between connector plate 22A and electrode terminal 11A, thereby improving the joint performance between connector plate 22A and electrode terminal 11A. Similarly, by forming connector plate 22B from the same material as electrode terminal 11B, it is possible to effectively prevent voids from being formed at the joint between connector plate 22B and electrode terminal 11B, thereby improving the joint performance between connector plate 22B and electrode terminal 11B.

[0049] Furthermore, in this embodiment, by forming each of the conductive plates 26 from a material with higher thermal conductivity and electrical conductivity than at least one of the connector plates 22A, 22B, a temperature rise in the bus bar 21 due to a large current flowing through the bus bar 21 is further appropriately suppressed. Therefore, by forming each of the conductive plates 26 from a material with higher thermal conductivity and electrical conductivity than at least one of the connector plates 22A, 22B, it is possible to further increase the current flowing through the bus bar 21 compared to when the conductive plates 26 are formed from the same material as the connector plates 22A, 22B. This enables the battery module 20 including the batteries 1A, 1B to have a higher output. Furthermore, by forming each of the conductive plates 26 from a material with higher thermal conductivity and electrical conductivity than at least one of the connector plates 22A, 22B, it is possible to reduce the number of conductive plates 26 constituting the stacked plate body 23 while still allowing the same magnitude of current to flow through the bus bar 21 as when the conductive plates 26 are formed from the same material as the connector plates 22A, 22B.

[0050] (Modification of the first embodiment) A modification of the first embodiment described above will now be described. In the first modification shown in Fig. 5, in the portion between bending positions B1 and B2 of the plate stack 23, each of the conductive plates 26 does not abut against an adjacent conductive plate 26 in the stacking direction. In the portion between bending positions B1 and B2 of the plate stack 23, a gap 31 is formed between each of the plurality of conductive plates 26 and the adjacent conductive plate 26 in the stacking direction. In this modification, the plate stack 23 includes a pair of plate abutting portions 32A and 32B and a plate spacing portion 33.

[0051] The plate abutting portion (first plate abutting portion) 32A is formed at the end of the plate stack 23 on the side where the joint portion (first joint portion) 27A is located in the length direction, and is formed in a portion between the end S1 and the bending position B1. At the plate abutting portion 32A, each of the plurality of conductive plates 26 abuts against an adjacent conductive plate 26 in the stacking direction. Furthermore, in the plate stack 23, the plurality of conductive plates 26 are joined to one another at the plate abutting portion 32A. The plate abutting portion (second plate abutting portion) 32B is formed at the end of the plate stack 23 on the side where the joint portion (second joint portion) 27B is located in the length direction, and is formed in a portion between the end S2 and the bending position B2. Therefore, the plate abutting portion 32B is formed at the end of the plate stack 23 opposite the plate abutting portion 32A in the length direction. At the plate abutting portions 32B, each of the plurality of conductive plates 26 abuts against an adjacent conductive plate 26 in the stacking direction. In the plate stack 23, the plurality of conductive plates 26 are joined to one another at the plate abutting portions 32B. In this modification, the edge surface E1 of each of the multiple conductive plates 26 is offset from the edge surfaces E1 of the other conductive plates 26 in the length direction of the stacked plate body 23. The edge S1 of the stacked plate body 23 is formed only by the edge surface E1 of the conductive plate 26A that is closest to the electrode terminals 11A and 11B. Among the conductive plates 26 other than the conductive plate 26A, the more distal the conductive plate 26 is from the electrode terminals 11A and 11B, the more the edge surface E1 is positioned toward the edge S2 side relative to the edge S1. In this modification, the edge surface E2 of each of the multiple conductive plates 26 is offset from the edge surfaces E2 of the other conductive plates 26 in the length direction of the stacked plate body 23. The edge S2 of the stacked plate body 23 is formed only by the edge surface E2 of the conductive plate 26A that is closest to the electrode terminals 11A and 11B. Among the conductive plates 26 other than the conductive plate 26A, the more distal the conductive plate 26 is from the electrode terminals 11A and 11B, the more the edge surface E2 is positioned toward the end S1 side relative to the end S2.

[0052] The plate spacing portion 33 is formed between the plate abutting portions 32A and 32B in the longitudinal direction of the plate stack 23, and is formed in the convex portion between the bending positions B1 and B2. In the plate spacing portion 33 (convex portion), each of the plurality of conductive plates 26 is formed in a curved shape. In this modification, in the curved shape of each of the conductive plates 26 formed in the plate spacing portion 33, the side on which the electrode terminals 11A and 11B are located in the first direction is the inner side of the curve, and the side away from the electrode terminals 11A and 11B in the first direction is the outer side of the curve.

[0053] However, in the plate spacing portion 33 of this modified example, the curvature of the curved shape of the conductive plate 26 increases as it is positioned closer to the electrode terminals 11A and 11B. Therefore, among the multiple conductive plates 26, the conductive plate 26A that is closest to the electrode terminals 11A and 11B has the largest curvature of the curved shape in the plate spacing portion 33, and the conductive plate 26B that is most distal to the electrode terminals 11A and 11B has the smallest curvature of the curved shape in the plate spacing portion 33. In this modified example, by making the curvature of the curved shape different for each conductive plate 26 in the plate spacing portion 33 as described above, a gap 31 is formed in the plate spacing portion 33 between each of the multiple conductive plates 26 and the conductive plate 26 adjacent to it in the stacking direction.

[0054] In this modification, too, in the region between bending positions B1 and B2 in the longitudinal direction of the plate stack 23, the conductive plates 26 are not joined to the other conductive plates 26. That is, in the plate separation portion 33, the conductive plates 26 are not joined to the other conductive plates 26. Therefore, in the plate stack 23 of this modification, non-jointed portions in which the conductive plates 26 are not joined to the other conductive plates 26 are formed over most of the longitudinal direction.

[0055] This modification also achieves the same effects and advantages as the first embodiment, etc. Therefore, the busbar 21 of this modification also ensures an appropriate cross-sectional area in the direction perpendicular or substantially perpendicular to the extension direction of the electrical path, and appropriately alleviates the stress applied from the busbar 21 to each of the electrode terminals 11A, 11B. Furthermore, in this modification, in the plate spacing portion 33, a gap 31 is formed between each of the plurality of conductive plates 26 and the conductive plate 26 adjacent to it in the stacking direction. This improves the heat dissipation of the plate stack 23 of the busbar 21, and further appropriately suppresses the temperature rise in the busbar 21.

[0056] 5 and the like, the second modified example shown in FIG. 6 also includes a pair of plate contact portions 32A, 32B and a plate spacing portion 33, and a gap 31 is formed in the plate spacing portion 33 between each of the plurality of conductive plates 26 and an adjacent conductive plate 26 in the stacking direction. However, in this modified example, the edge surfaces E1 of the plurality of conductive plates 26 are not or only slightly misaligned relative to one another in the longitudinal direction of the stacked plate body 23. The edge surfaces E1 of all the conductive plates 26 form the edge S1 of the stacked plate body 23. In this modified example, the edge surfaces E2 of the plurality of conductive plates 26 are not or only slightly misaligned relative to one another in the longitudinal direction of the stacked plate body 23. The edge surfaces E2 of all the conductive plates 26 form the edge S2 of the stacked plate body 23.

[0057] Furthermore, in the plate stack 23 of this modified example, the conductive plates 26 located closer to the electrode terminals 11A and 11B have a shorter extension length along the longitudinal direction of the plate stack 23 from the edge surface E1 to the edge surface E2. The conductive plates 26 located closer to the electrode terminals 11A and 11B have a shorter extension length along the longitudinal direction of the plate stack 23 at the plate spacing portion 33 (the convex portion between the bending positions B1 and B2). Therefore, among the multiple conductive plates 26, the conductive plate 26A located closest to the electrode terminals 11A and 11B has the shortest extension length along the longitudinal direction of the plate stack 23, and the conductive plate 26B located most distal to the electrode terminals 11A and 11B has the longest extension length along the longitudinal direction of the plate stack 23. In this modified example, as described above, by making the extension length along the longitudinal direction of each conductive plate 26 in the stacked plate body 23 different, a gap 31 is formed in the plate spacing portion 33 between each of the multiple conductive plates 26 and the conductive plate 26 adjacent to it in the stacking direction.

[0058] In this modification, since gaps 31 are formed in plate spacing portions 33, heat dissipation from stacked plate body 23 of busbar 21 is improved, and temperature rise in busbar 21 is more appropriately suppressed, as in the modification shown in FIG. 5 and the like. Furthermore, in this modification, edge surfaces E1 of the plurality of conductive plates 26 are not misaligned or only slightly misaligned relative to one another in the length direction of stacked plate body 23. Furthermore, edge surfaces E2 of the plurality of conductive plates 26 are not misaligned or only slightly misaligned relative to one another in the length direction of stacked plate body 23. This improves workability in assembling (forming) stacked plate body 23 and forming busbar 21.

[0059] 7, the busbar 21 is not provided with connector plates 22A, 22B, and the busbar 21 is formed only from the plate stack 23. In this modification, the joint (first joint) 27A of the plate stack 23 is joined to the electrode terminal (first conductive member) 11A of the battery 1A, which is a conductive member separate from the plate stack 23. The joint (second joint) 27B of the plate stack 23 is joined to the electrode terminal (second conductive member) 11B of the battery 1B, which is a conductive member separate from the plate stack 23 and the electrode terminal 11A. Note that in some modifications, only one of the connector plates 22A, 22B may be provided on the busbar 21.

[0060] Even in a configuration in which at least one of the connector plates 22A, 22B is not provided on the busbar 21, as in the modified example shown in FIG. 7 and the like, the busbar 21 includes the stacked plate body 23, as in the first embodiment and the like. Therefore, the modified example shown in FIG. 7 and the like achieves the same functions and effects as the first embodiment and the like. That is, the busbar 21 of the modified example shown in FIG. 7 and the like also ensures an appropriate cross-sectional area perpendicular or substantially perpendicular to the extension direction of the electrical path, and appropriately alleviates the stress applied from the busbar 21 to each of the electrode terminals 11A, 11B. Furthermore, in a busbar 21 in which the stacked plate body 23 is provided, as in the first embodiment and the like, the number of conductive plates 26 forming the stacked plate body 23 is not particularly limited as long as it is two or more.

[0061] (Second embodiment) Next, a busbar 21 according to a second embodiment will be described. The busbar 21 of this embodiment is a modified version of the busbar 21 of the first embodiment, etc., as described below. Therefore, a description of the configuration of the busbar 21 of this embodiment that is the same as that of the first embodiment, etc., will be omitted.

[0062] Fig. 8 shows busbar 21 of this embodiment, and Fig. 9 shows busbar 21 of this embodiment, two electrode terminals 11A and 11B to which busbar 21 is connected (joined), and the configuration of the vicinity thereof. As with the above-described embodiments, busbar 21 of this embodiment also defines a first direction (the direction indicated by arrows Z3 and Z4), a second direction (the direction indicated by arrows Y3 and Y4), and a third direction (the direction indicated by arrows X3 and X4). Fig. 8 shows busbar 21 as viewed from one side in the first direction, and Fig. 10 shows busbar 21 as viewed from one side in the third direction.

[0063] In this embodiment, the busbar 21 also includes connector plates 22A and 22B, and the length, width, and thickness directions of each of the connector plates 22A and 22B are defined in the same manner as in the first embodiment. However, in this embodiment, the busbar 21 includes a plurality of conductive wires 41 instead of the plate stack 23. In the example shown in FIGS. 8 and 9, the busbar 21 includes ten conductive wires 41. Each of the plurality of conductive wires 41 is made of a conductive material and is conductive. An example of a material for the conductive wires 41 is copper. Each of the conductive wires 41 has a central axis, and an axial direction along the central axis is defined for each of the conductive wires 41.

[0064] Each of the plurality of conductive wires 41 has a bonding portion (first bonding portion) 42A formed at one axial end thereof to be bonded to a connector plate (first connector plate) 22A, which is a conductive member (first conductive member). Each of the plurality of conductive wires 41 also has a bonding portion (second bonding portion) 42B formed at the axial end opposite the bonding portion 42A to be bonded to a connector plate (second connector plate) 22B, which is a conductive member (second conductive member). At each of the bonding portions 42A, a corresponding one of the conductive wires 41 is bonded to the connector plate 22A by ultrasonic welding or the like. Similarly, at each of the bonding portions 42B, a corresponding one of the conductive wires 41 is bonded to the connector plate 22B by ultrasonic welding or the like.

[0065] Each of the plurality of conductive wires 41 is positioned apart from the other conductive wires 41 in at least one of the first direction of the bus bar 21 (the thickness direction of the connector plates 22A and 22B) and the third direction of the bus bar 21 (the width direction of the connector plates 22A and 22B). Therefore, the plurality of conductive wires 41 do not contact each other in the bus bar 21. In one example shown in FIGS. 8 and 9 , the plurality of conductive wires 41 includes five conductive wires 41A and five conductive wires 41B. The five conductive wires 41A are positioned apart from each other in the third direction (the width direction of the connector plates 22A and 22B), and the five conductive wires 41B are positioned apart from each other in the third direction. Furthermore, the conductive wires 41A are positioned apart from the conductive wires 41B in the first direction (the thickness direction of the connector plates 22A and 22B). The conductive wire 41A extends through a region that is farther away from the electrode terminals 11A and 11B in the first direction than the conductive wire 41B.

[0066] In this embodiment, as described above, the busbar 21 is provided with a plurality of conductive wires 41. Each of the plurality of conductive wires 41 has a small diameter and a small cross-sectional area. However, by providing a plurality of conductive wires 41, and particularly by increasing the number of conductive wires 41, the total cross-sectional area of ​​the plurality of conductive wires 41 can be ensured to be a certain size. In the busbar 21 of this embodiment, the total cross-sectional area of ​​the plurality of conductive wires 41 is the cross-sectional area perpendicular or substantially perpendicular to the extension direction of the electrical paths. Therefore, even if the electrical paths in the busbar 21 are formed by the plurality of conductive wires 41, the cross-sectional area of ​​the busbar 21 perpendicular or substantially perpendicular to the extension direction of the electrical paths can be ensured to be an appropriate size.

[0067] In the present embodiment, as described above, the bus bar 21 is provided with the plurality of conductive wires 41. Therefore, compared to a case where a plate-like portion integral with the connector plates 22A, 22B is provided instead of the plurality of conductive wires 41, the stress applied from the bus bar 21 to each of the electrode terminals 11A, 11B is alleviated.

[0068] As described above, the bus bar 21 of this embodiment also ensures an appropriate cross-sectional area in the direction perpendicular or substantially perpendicular to the extension direction of the electrical path, and appropriately alleviates the stress applied to each of the electrode terminals 11A, 11B from the bus bar 21. Therefore, this embodiment also provides the same functions and effects as the above-described embodiments.

[0069] (Modification of the second embodiment) In a modification of the second embodiment shown in FIG. 10 , the bus bar 21 is not provided with connector plates 22A, 22B, and is formed solely from a plurality of conductive wires 41. In this modification, the bonding portion (first bonding portion) 42A of each conductive wire 41 is bonded to an electrode terminal (first conductive member) 11A of battery 1A, which is a conductive member separate from the conductive wires 41. The bonding portion (second bonding portion) 42B of each conductive wire 41 is bonded to an electrode terminal (second conductive member) 11B of battery 1B, which is a conductive member separate from the conductive wires 41 and electrode terminals 11A. Note that in a modification, only one of the connector plates 22A, 22B may be provided on the bus bar 21.

[0070] Even in a configuration in which at least one of connector plates 22A, 22B is not provided on bus bar 21, as in the modified example shown in FIG. 10 and the like, bus bar 21 includes multiple conductive wires 41, as in the second embodiment and the like. Therefore, the modified example shown in FIG. 10 and the like achieves the same functions and effects as the second embodiment and the like. That is, the bus bar 21 of the modified example shown in FIG. 10 and the like also ensures an appropriate cross-sectional area perpendicular or substantially perpendicular to the extension direction of the electrical path, and appropriately alleviates the stress applied from bus bar 21 to each of electrode terminals 11A, 11B. Furthermore, in a bus bar 21 in which multiple conductive wires 41 are provided, as in the second embodiment and the like, the number of conductive wires 41 provided on bus bar 21 is not particularly limited as long as it is two or more.

[0071] According to at least one of these embodiments or examples, the busbar includes a stacked plate body in which a plurality of conductive plates are stacked. The stacked plate body is joined to a first conductive member, which is a conductive member separate from the stacked plate body, at a first joint formed at one end of the stacked plate body in the longitudinal direction of the stacked plate body. The stacked plate body is also joined to a second conductive member, which is a conductive member separate from the stacked plate body and the first conductive member, at a second joint formed at an end of the stacked plate body opposite the first joint in the longitudinal direction of the stacked plate body. This ensures an appropriate cross-sectional area perpendicular or substantially perpendicular to the extension direction of the electrical path, thereby providing a busbar in which stress applied to the electrode terminals is appropriately alleviated.

[0072] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. The following are additional notes. [1] A bus bar that electrically connects two electrode terminals that are spaced apart from each other, a stacked plate body including a plurality of conductive plates each having electrical conductivity, the plurality of conductive plates being stacked on top of one another; a first joint portion formed at one end of the stacked plate body in a length direction of the stacked plate body that intersects with the stacking direction of the plurality of conductive plates, and joined to a first conductive member that is a conductive member separate from the stacked plate body; a second joint portion formed at an end portion of the stacked plate body opposite to the first joint portion in the longitudinal direction, and joined to a second conductive member that is a conductive member different from the stacked plate body and the first conductive member; A bus bar comprising: [2] a first connector plate that serves as the first conductive member to which the first joint portion of the stacked plate body is joined and that is joined to a first electrode terminal that is one of the two electrode terminals; a second connector plate which serves as the second conductive member to which the second joint portion of the stacked plate body is joined and which is joined to a second electrode terminal which is another one of the two electrode terminals other than the first electrode terminal; The busbar of [1] further comprising: [3] The busbar according to [2], wherein the thickness of each of the plurality of conductive plates is thinner than the thickness of each of the first connector plate and the second connector plate. [4] The busbar of [3], wherein the total thickness of the plurality of conductive plates is the same as the thickness of each of the first connector plate and the second connector plate. [5] The first connector plate is formed from the same material as the first electrode terminal; the second connector plate is formed from the same material as the second electrode terminal; each of the plurality of conductive plates is formed from a material having higher thermal conductivity and electrical conductivity than at least one of the first connector plate and the second connector plate; [2] to [4]. [6] A first electrode terminal, which is one of the two electrode terminals, serves as the first conductive member to which the first joint portion of the stacked plate body is joined, a second electrode terminal, which is one of the two electrode terminals other than the first electrode terminal, serves as the second conductive member to which the second joint portion of the stacked plate body is joined; [1] Busbar. [7] The stacked plate body is a first plate abutment portion formed at an end portion of the stacked plate body on the side where the first joint portion is located in the longitudinal direction, where each of the plurality of conductive plates abuts against an adjacent conductive plate in the stacking direction; a second plate abutment portion formed at an end portion of the stacked plate body on the side where the second joint portion is located in the longitudinal direction, where each of the plurality of conductive plates abuts against an adjacent conductive plate in the stacking direction; a plate spacing portion formed between the first plate contact portion and the second plate contact portion in the longitudinal direction of the stacked plate body, and forming a gap between each of the plurality of conductive plates and an adjacent conductive plate in the stacking direction; The busbar of any one of [1] to [6], comprising: [8] In the stacked plate body, Each of the plurality of conductive plates is formed in the plate separation portion in a curved shape in which the curvature of the conductive plate increases as the conductive plate is positioned closer to the two electrode terminals; and The plurality of conductive plates are each extended such that the conductive plate positioned closer to the two electrode terminals has a shorter extension length along the longitudinal direction of the stacked plate body, or [7] A busbar, which is at least one of the above. [9] A bus bar electrically connecting two electrode terminals spaced apart from each other, a plurality of conductive wires each having electrical conductivity; a first bonding portion formed at one end of each of the plurality of conductive wires and bonded to a first conductive member that is a conductive member separate from the plurality of conductive wires; a second bonding portion formed on an end of each of the plurality of conductive wires opposite to the first bonding portion, and bonded to a second conductive member that is a conductive member different from the plurality of conductive wires and the first conductive member; A bus bar comprising:

[10] A first connector plate, to which the first bonding portions of the plurality of conductive wires are bonded as the first conductive members and which is joined to a first electrode terminal that is one of the two electrode terminals; a second connector plate, to which the second bonding portions of the respective conductive wires are bonded as the second conductive members, and which is joined to a second electrode terminal other than the first electrode terminal of the two electrode terminals; [9] The busbar further comprising:

[11] A first electrode terminal, which is one of the two electrode terminals, serves as the first conductive member to which the first bonding portions of each of the plurality of conductive wires are bonded; a second electrode terminal, which is one of the two electrode terminals other than the first electrode terminal, serves as the second conductive member to which the second bonding portions of each of the plurality of conductive wires are bonded; [9] Busbar.

[12] Any one of the busbars [1] to

[11] ; a first battery including a first electrode terminal that is one of the two electrode terminals; a second battery including a second electrode terminal that is one of the two electrode terminals other than the first electrode terminal, the second electrode terminal being electrically connected to the first electrode terminal via the bus bar; A battery module comprising:

Claims

1. A bus bar electrically connecting a first electrode terminal and a second electrode terminal that are spaced apart from each other, a stacked plate body formed by stacking a plurality of conductive plates, the stacked plate body having a first joint portion formed at one end in an arrangement direction of the first electrode terminal and the second electrode terminal and joined to a first connector plate joined to the first electrode terminal, and a second joint portion formed at an end on the opposite side of the arrangement direction from the first joint portion and joined to a second connector plate joined to the second electrode terminal, the plate stack includes a first plate abutment portion at the end portion where the first joint portion in the arrangement direction is located, where adjacent conductive plates in the stacking direction abut against each other, the plate stack includes a second plate abutment portion at the end portion where the second joint portion in the arrangement direction is located, where adjacent conductive plates in the stacking direction abut against each other, the plate stack body includes a plate spacing portion between the first plate abutting portion and the second plate abutting portion, where adjacent conductive plates in the stacking direction are spaced apart from each other. Busbar.

2. The bus bar according to claim 1 , wherein the thickness of each of the plurality of conductive plates is thinner than the thickness of the first connector plate and the thickness of the second connector plate.

3. The bus bar according to claim 2 , wherein the total thickness of the plurality of conductive plates is the same as the thickness of the first connector plate and the thickness of the second connector plate.

4. the first connector plate is formed from the same material as the first electrode terminal; the second connector plate is formed from the same material as the second electrode terminal; each of the plurality of conductive plates is formed from a material having higher thermal conductivity and electrical conductivity than at least one of the first connector plate and the second connector plate; The bus bar according to any one of claims 1 to 3.

5. A bus bar electrically connecting a first electrode terminal and a second electrode terminal that are arranged apart from each other, a stacked plate body formed by stacking a plurality of conductive plates, the stacked plate body having a first joint portion formed at an end portion on one side in an arrangement direction of the first electrode terminal and the second electrode terminal and joined to the first electrode terminal, and a second joint portion formed at an end portion on an opposite side in the arrangement direction from the first joint portion and joined to the second electrode terminal; the plate stack includes a first plate abutment portion at the end portion where the first joint portion in the arrangement direction is located, where adjacent conductive plates in the stacking direction abut against each other, the plate stack includes a second plate abutment portion at the end portion where the second joint portion in the arrangement direction is located, where adjacent conductive plates in the stacking direction abut against each other, the plate stack body includes a plate spacing portion between the first plate abutting portion and the second plate abutting portion, where adjacent conductive plates in the stacking direction are spaced apart from each other. Busbar.

6. The stacked plate body is In the plate separation portion, the conductive plate located closer to the first electrode terminal and the second electrode terminal is curved with a larger curvature, and / or the conductive plate located closer to the first electrode terminal and the second electrode terminal has a shorter length along the extending direction; The bus bar according to any one of claims 1 to 5.

7. A busbar according to any one of claims 1 to 6, wherein each of the plurality of conductive plates of the stacked plate body is a conductive wire having electrical conductivity.

8. The bus bar according to any one of claims 1 to 7; a first battery including the first electrode terminal; a second battery including the second electrode terminal; A battery module comprising:

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