Bassba

Abstract

To dispose a tolerance absorption structure in an appropriate place.SOLUTION: A bus bar comprises a bus bar main body 10 disposed between one battery cell and the other battery cell which are adjacent to each other in a battery module BM which is molded tabular and in which a plurality of battery cells BC is arrayed. The bus bar main body is bisected into a first terminal connection body 11, which defines a first electrode terminal BCa of one battery cell as a weld target, and a second terminal connection body 12 which defines a second electrode terminal BCa of the other battery cell as a weld target. At least one of the first terminal connection body and the second terminal connection body includes a through hole 13, in which the electrode terminal of the weld target is exposed, and a flexible part 14 which protrudes from an outer peripheral edge of the through hole toward a hole center and has flexibility. The flexible part includes a terminal weld portion 14a which is welded to the electrode terminal of the weld target, and a spring portion 14b which is provided between the terminal weld portion and a stationary end on the side of the outer peripheral edge of the through hole and elastically deformable in its own protrusion direction and the reverse direction thereof.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, in a battery module in which a plurality of battery cells are arranged, each electrode terminal of adjacent battery cells in the arrangement direction is physically and electrically connected by a single bus bar. The bus bar includes a first terminal connection body that is physically and electrically connected to one electrode terminal, and a second terminal connection body that is physically and electrically connected to the other electrode terminal. On the other hand, in a battery module, in order to absorb misalignment within the design tolerance range of the terminal pitch due to thermal expansion and contraction of the battery cells, and misalignment within the design tolerance range of the terminal pitch due to assembly tolerance variation of the plurality of battery cells, a tolerance absorption structure is provided in the bus bar. In the bus bar, a tolerance absorption structure such as a notch or other thinning portion is provided between the first terminal connection body and the second terminal connection body (that is, in the central portion in the arrangement direction of the plurality of battery cells) to absorb misalignment of the terminal pitch. For example, this type of bus bar is disclosed in Patent Document 1 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a bus bar, the central portion between the first terminal connection body and the second terminal connection body where the tolerance absorption structure is provided is most likely to generate heat, so it is necessary to increase the heat resistance by increasing the cross-sectional area of the central portion. However, in a conventional bus bar, the tolerance absorption structure and the heat resistance structure are provided in the same place (the central portion), and there is room for improvement regarding the arrangement of the tolerance absorption structure.

[0005] Therefore, the object of the present invention is to provide a busbar in which a tolerance absorption structure is arranged in a suitable location. [Means for solving the problem]

[0006] The present invention comprises a busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module, wherein the busbar body is divided into a first terminal connector for welding to the first electrode terminal of one battery cell and a second terminal connector for welding to the second electrode terminal of the other battery cell, and at least one of the first terminal connector and the second terminal connector has a through hole for exposing the electrode terminal to be welded and a flexible portion that protrudes from the outer peripheral edge of the through hole toward the center of the hole and is flexible, and the flexible portion has a terminal welding portion for welding to the electrode terminal to be welded and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction. The flexible portion is formed in a cantilever shape, projecting from the outer edge of the through hole toward the center of the hole in a direction perpendicular to the arrangement direction of the plurality of battery cells, and a pair of such flexible portions are provided with their projection directions opposite to each other, and the terminal welding portion is provided at the free end of the flexible portion. It is characterized by the following: Furthermore, the present invention comprises a busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, wherein the busbar body is divided into a first terminal connector to be welded to the first electrode terminal of one of the battery cells and a second terminal connector to be welded to the second electrode terminal of the other battery cell, and at least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded and from the outer peripheral edge of the through hole The device has a flexible portion that protrudes toward the center of the hole and is flexible, the flexible portion having a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and the opposite direction, the flexible portion is formed in a cantilever shape that protrudes toward the center of the hole from the outer peripheral edge of the through hole in the arrangement direction of the plurality of battery cells, and a pair is provided with their protruding directions in opposite directions, and the terminal welding portion is provided at the free end of the flexible portion. Furthermore, the present invention comprises a busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module, wherein the busbar body is divided into a first terminal connector for welding to the first electrode terminal of one battery cell and a second terminal connector for welding to the second electrode terminal of the other battery cell, and at least one of the first terminal connector and the second terminal connector has a through hole for exposing the electrode terminal to be welded and a flexible portion that protrudes from the outer peripheral edge of the through hole toward the center of the hole and is flexible, the flexible portion has a terminal welding portion for welding to the electrode terminal to be welded and a fixed end on the outer peripheral edge side of the through hole, and is provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, and is in its own protruding direction and in the opposite direction The first terminal connector has an elastically deformable spring portion, the first terminal connector has a first through hole as the through hole, and the second terminal connector has a second through hole as the through hole, and the second terminal connector has a second flexible portion as the flexible portion, the first flexible portion is formed in a cantilever shape projecting from the outer edge of the first through hole toward the center of the hole in a direction perpendicular to the arrangement direction of the plurality of battery cells, the terminal welding portion of the first flexible portion is provided at the free end of the first flexible portion and welded to the first electrode terminal, the second flexible portion is formed in a cantilever shape projecting from the outer edge of the second through hole toward the center of the hole in the arrangement direction, and the terminal welding portion of the second flexible portion is provided at the free end of the second flexible portion and welded to the second electrode terminal. Furthermore, the present invention comprises a busbar body formed in a flat plate shape and positioned between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, wherein the busbar body is divided into a first terminal connector to be welded to the first electrode terminal of one of the battery cells and a second terminal connector to be welded to the second electrode terminal of the other battery cell, and at least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded and extends from the outer edge of the through hole to the center of the hole The device has a flexible portion that protrudes toward and is flexible, the flexible portion having a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and the opposite direction, the through hole is formed in a circular shape, the flexible portion is formed in a cantilever shape that protrudes from the outer peripheral edge of the through hole toward the center of the hole, and a plurality of flexible portions are provided at equal intervals around the circumference of the through hole, and the terminal welding portion is provided at the free end of the flexible portion.

[0007] Furthermore, the present invention comprises a busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, wherein the busbar body is divided into a first terminal connector to be welded to the first electrode terminal of one of the battery cells and a second terminal connector to be welded to the second electrode terminal of the other battery cell, and at least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion to be welded to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and the opposite direction. The flexible portion is formed in a cantilevered beam shape, with each protruding toward the center of the hole from two opposing locations on the outer peripheral edge of the through hole in a direction perpendicular to the arrangement direction of the plurality of battery cells. The terminal welding portion is located in the center of the flexible portion and in the center of the through hole, and the spring portion is provided between the terminal welding portion and one fixed end, and between the terminal welding portion and the other fixed end. Furthermore, the present invention comprises a busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, wherein the busbar body is divided into a first terminal connector to be welded to the first electrode terminal of one of the battery cells and a second terminal connector to be welded to the second electrode terminal of the other battery cell, and at least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion for welding to an electrode terminal to be welded, and a spring portion provided between the terminal welding portion and a fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and the opposite direction, wherein the flexible portion is formed in a cantilevered beam shape with each protruding toward the center of the hole from two opposite locations on the outer peripheral edge of the through hole in the arrangement direction of the plurality of battery cells, the terminal welding portion is located in the center of the flexible portion and in the center of the through hole, and the spring portion is provided between the terminal welding portion and one fixed end and between the terminal welding portion and the other fixed end. Furthermore, the present invention comprises a busbar body formed in a flat plate shape and positioned between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, wherein the busbar body is divided into a first terminal connector to be welded to the first electrode terminal of one of the battery cells and a second terminal connector to be welded to the second electrode terminal of the other battery cell, and at least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded. The first terminal connector has a first through hole as the through hole and a first flexible part as the flexible part, and the second terminal connector has a second through hole as the through hole and a flexible part as the flexible part, the flexible part has a terminal welding part for welding to the electrode terminal to be welded and a spring part provided between the terminal welding part and the fixed end on the outer edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction, the first terminal connector has a first through hole as the through hole and a first flexible part as the flexible part, the second terminal connector has a second through hole as the through hole and a second flexible part as the flexible part The first flexible portion is formed in a cantilever shape, with the first flexible portion projecting toward the center of the first through-hole from two opposing locations on the outer edge of the first through-hole in a direction perpendicular to the arrangement direction of the plurality of battery cells, the terminal welding portion of the first flexible portion is located in the center of the first flexible portion and in the center of the first through-hole and is welded to the first electrode terminal, and the spring portion of the first flexible portion is located between the terminal welding portion and one fixed end of the first flexible portion and between the terminal welding portion and the other fixed end The second flexible portion is provided between the two, and the second flexible portion is formed in a cantilevered beam shape, projecting toward the center of the hole from two opposite locations on the outer edge of the second through hole in the direction of arrangement, the terminal welding portion of the second flexible portion is located in the center of the second flexible portion and in the center of the second through hole and is welded to the second electrode terminal, and the spring portion of the second flexible portion is provided between the terminal welding portion and one fixed end of the second flexible portion and between the terminal welding portion and the other fixed end, respectively. Furthermore, the present invention comprises a first busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, and a second busbar body that is physically and electrically connected to the first busbar body, wherein the first busbar body has a notch or through hole that exposes the first electrode terminal of one of the battery cells and is divided into a first terminal connector to which the first electrode terminal is electrically connected via the second busbar body and a second terminal connector to which the second electrode terminal of the other battery cell is to be welded, and the second busbar body has the notch or through hole of the first terminal connector The device is characterized by having: a terminal welding portion arranged in the through-hole and welded to the first electrode terminal; a first busbar welding portion welded to the first terminal connector; a second busbar welding portion welded to the first terminal connector; a first spring portion provided between the terminal welding portion and the first busbar welding portion and elastically deformable in the direction of arrangement of the terminal welding portion and the first busbar welding portion and in the opposite direction; a second spring portion provided between the terminal welding portion and the second busbar welding portion and elastically deformable in the direction of arrangement of the terminal welding portion and the second busbar welding portion and in the opposite direction; and a circuit conductor connection portion that is physically and electrically connected to a circuit conductor to be electrically connected to a battery monitoring unit. [Effects of the Invention]

[0008] The busbar according to the present invention functions as a tolerance-absorbing structure by comprising a busbar body having such a structure, or by comprising a first busbar body and a second busbar body having such a structure. For example, even if the spacing between the electrode terminals of two adjacent battery cells in the arrangement direction (so-called inter-terminal pitch) is within the design tolerance range, this busbar can be welded to each electrode terminal by absorbing the deviation in the inter-terminal pitch with the spring portion. Furthermore, even if the inter-terminal pitch or the position of the electrode terminals is shifted within the design tolerance range due to thermal expansion or contraction of the battery cells during use of the battery module, this busbar can be made to follow the deviation in the inter-cell pitch within the design tolerance range due to thermal expansion or contraction of the battery cells, or to follow the deviation in the position of the electrode terminals within the design tolerance range due to thermal expansion or contraction of the battery cells, by absorbing the deviation in the inter-terminal pitch or the position of the electrode terminals with the spring portion. Furthermore, the busbar according to the present invention has a spring portion (tolerance absorption structure) located in a place that avoids the central portion between the first terminal connector and the second terminal connector, so that a heat-resistant structure can be provided in the central portion without being constrained by the tolerance absorption structure. Moreover, the busbar according to the present invention has a spring portion (tolerance absorption structure) at the welding point with the electrode terminal where the temperature reduction effect due to heat dissipation of the battery cell is highest, so that its own heat generation can be suppressed and the heat-resistant structure (i.e., the cross-sectional area of ​​the central portion) can be made smaller. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing the busbar of specific example 1 in the embodiment. [Figure 2] Figure 2 is an explanatory diagram of the busbar in Specific Example 1 of the embodiment. [Figure 3] Figure 3 is an explanatory diagram illustrating an example of the flexibility of a flexible part when the electrode terminals are misaligned in a direction perpendicular to the arrangement direction of multiple battery cells. [Figure 4] Figure 4 is an explanatory diagram illustrating an example of the flexibility of the flexible portion when the electrode terminals are misaligned in a direction perpendicular to the plane of the first terminal connector (the plane of the first electrode terminals). [Figure 5] FIG. 5 is a perspective view showing the bus bar of Specific Example 2 in the embodiment. [Figure 6] FIG. 6 is a perspective view showing the bus bar of Specific Example 3 in the embodiment. [Figure 7] FIG. 7 is a perspective view showing the bus bar of Specific Example 4 in the embodiment. [Figure 8] FIG. 8 is a perspective view showing the bus bar of Specific Example 5 in the embodiment. [Figure 9] FIG. 9 is a perspective view showing the bus bar of Specific Example 6 in the embodiment. [Figure 10] FIG. 10 is a perspective view showing the bus bar of Specific Example 7 in the embodiment. [Figure 11] FIG. 11 is a perspective view showing one of the specifications of the battery module. [Figure 12] FIG. 12 is a perspective view showing the bus bar of Specific Example 1 in the modified form. [Figure 13] FIG. 13 is an explanatory view for explaining the clamping portion of the first bus bar body of Specific Example 1 in the modified form. [Figure 14] FIG. 14 is a perspective view showing the bus bar of Specific Example 2 in the modified form.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, an embodiment of the bus bar according to the present invention will be described in detail based on the drawings. Note that the present invention is not limited by this embodiment.

[0011] [Embodiment] One embodiment of the bus bar according to the present invention will be described based on FIGS. 1 to 10.

[0012] First, the outline of the bus bar of this embodiment will be described.

[0013] In this embodiment, the busbar in a battery module BM (Figure 11) in which multiple battery cells BC are arranged (for example, arranged in a row), electrically connects the electrode terminals BCa of adjacent battery cells BC to each other by physically and electrically connecting them in the direction of the arrangement. Furthermore, this busbar is electrically connected to a battery monitoring unit (not shown) via a circuit conductor (not shown), allowing the battery monitoring unit to monitor the battery state (voltage, current, temperature, etc.) of the battery cells BC. The circuit conductor is, for example, an electric wire or a wiring pattern on a flexible printed circuit board (FPC).

[0014] A battery cell BC comprises a cell body BCb and positive and negative electrode terminals BCa (Figure 11). In the battery cell BC shown here, the cell body BCb is formed in a rectangular shape with six outer wall surfaces, and one of these six outer wall surfaces is provided with positive and negative flat electrode terminals BCa. In a battery module BM, multiple battery cells BC are arranged so that adjacent cell bodies BCb in the direction of arrangement face each other with one outer wall surface facing the other. In this battery module BM, one electrode terminal BCa of each battery cell BC is aligned along the direction of arrangement, and the other electrode terminal BCa of each battery cell BC is aligned along the direction of arrangement. Note that a battery cell BC may also have a positive electrode flat electrode terminal BCa and a negative electrode flat electrode terminal BCa on different outer wall surfaces among the six outer wall surfaces.

[0015] The busbar of this embodiment comprises a busbar body formed in a flat plate shape. This busbar body is positioned between two adjacent battery cells BC.

[0016] The busbar body is divided into a first terminal connector that is to be welded to the first electrode terminal BCa of one battery cell BC, and a second terminal connector that is to be welded to the second electrode terminal BCa of the other battery cell BC. At least one of the first and second terminal connectors has a through hole that exposes the electrode terminal BCa to be welded, and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible. Furthermore, the flexible portion has a terminal welding portion that is welded to the electrode terminal BCa to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction.

[0017] The busbar of this embodiment, by having a busbar body of such shape, allows the spring portion of the flexible part to function as a tolerance-absorbing structure. For example, even if the spacing between the electrode terminals BCa of two adjacent battery cells BC in the alignment direction (so-called inter-terminal pitch) is within the design tolerance range, this busbar can be welded to each electrode terminal BCa by absorbing the deviation in the inter-terminal pitch with the spring portion. Furthermore, even if the inter-terminal pitch or the position of the electrode terminals BCa is shifted within the design tolerance range due to thermal expansion or contraction of the battery cell BC during use of the battery module BM, this busbar can be made to follow the deviation in the inter-cell pitch within the design tolerance range due to thermal expansion or contraction of the battery cell BC, or to follow the position of the electrode terminals BCa within the design tolerance range due to thermal expansion or contraction of the battery cell BC, by absorbing the deviation in the inter-terminal pitch or the position of the electrode terminals BCa within the design tolerance range due to thermal expansion or contraction of the battery cell BC with the spring portion.

[0018] Furthermore, in this embodiment, the busbar has a spring portion (tolerance absorption structure) located away from the central portion between the first terminal connector and the second terminal connector, so that the central portion can be given a heat-resistant structure without being constrained by the tolerance absorption structure. Moreover, in this embodiment, the busbar has a spring portion (tolerance absorption structure) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to the heat dissipation of the battery cell BC is highest, so that its own heat generation can be suppressed, and the size of the heat-resistant structure (i.e., the cross-sectional area of ​​the central portion) can be reduced.

[0019] The following describes a specific example of the busbar in this embodiment.

[0020] [Specific examples] Reference numeral 1 in Figure 1 indicates a busbar of specific example 1 in this embodiment. This busbar 1 comprises a busbar body 10 formed from a conductive material such as metal into a rectangular flat plate shape (Figure 1). The busbar body 10 is divided into a first terminal connector 11 to be welded to the first electrode terminal BCa of one battery cell BC, and a second terminal connector 12 to be welded to the second electrode terminal BCa of the other battery cell BC (Figure 1).

[0021] In this busbar body 10, a rectangular, flat first terminal connector 11 is provided with a through hole 13 and a flexible portion 14. The flexible portion 14 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and a rectangular, flat second terminal connector 12 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like, in the same way as conventional designs. Therefore, the through hole 13 is superimposed on the first electrode terminal BCa, exposing it. The through hole 13 is formed in a circular or square shape larger than the first electrode terminal BCa, exposing the entire flat surface (welded surface) of the first electrode terminal BCa. The through hole 13 shown here is formed in a circular shape. The second terminal connector 12 may also be provided with a through hole for welding.

[0022] The flexible portion 14 has a terminal welding portion 14a that is welded to the first electrode terminal BCa exposed through the through hole 13, and a spring portion 14b provided between the terminal welding portion 14a and the fixed end on the outer peripheral edge side of the through hole 13, which is elastically deformable in its own protruding direction and the opposite direction (Figures 1 and 2).

[0023] This flexible portion 14 is formed in a cantilever shape, projecting from the outer edge of the through hole 13 toward the center of the hole in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figures 1 and 2). The terminal welding portion 14a is provided at the free end of the flexible portion 14 (Figures 1 and 2).

[0024] This flexible portion 14 is formed by bending a rectangular, flat plate-shaped piece. The flexible portion 14 shown here has a flat spring portion (hereinafter referred to as the "second spring portion") 14c that protrudes from the outer edge of the through hole 13 toward the center of the hole in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figures 1 and 2). This second spring portion 14c is deformed by bending in a direction perpendicular to the plane of the first terminal connector 11 (the plane of the first electrode terminal BCa). The spring portion (hereinafter referred to as the "first spring portion") 14b shown here is formed in a V-shape or U-shape by raising the protruding end of the second spring portion 14c toward the opposite side from the first electrode terminal BCa side, and then folding back toward the first electrode terminal BCa side (Figures 1 and 2). This first spring portion 14b is deformed by bending in a direction perpendicular to the arrangement direction of the multiple battery cells BC. Furthermore, the terminal weld portion 14a is folded back towards the first electrode terminal BCa side of its first spring portion 14b, and protrudes toward the center of the through hole 13 in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figures 1 and 2). The terminal weld portion 14a shown here is formed in the shape of a rectangular flat plate parallel to the plane (welding surface) of the first electrode terminal BCa.

[0025] In this first terminal connector 11, a pair of flexible portions 14 are provided with their protruding directions facing opposite directions (Figures 1 and 2). This pair of flexible portions 14 are arranged in a direction perpendicular to the arrangement direction of the multiple battery cells BC.

[0026] In this specific example 1, even if the positions of the first electrode terminal BCa and the second electrode terminal BCa shift within the design tolerance range due to thermal expansion and contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the first spring portion 14b and the second spring portion 14c absorb the displacement of the electrode terminal BCa, thereby allowing the busbar 1 to follow the displacement of the electrode terminal BCa within the design tolerance range due to thermal expansion and contraction of one battery cell BC or the other battery cell BC. Figure 3 shows an example of the followability of the flexible portion 14 when the electrode terminal BCa shifts in a direction orthogonal to the arrangement direction of the multiple battery cells BC. Figure 4 also shows an example of the followability of the flexible portion 14 when the electrode terminal BCa shifts in a direction orthogonal to the plane of the first terminal connector 11 (the plane of the first electrode terminal BCa).

[0027] Furthermore, in this specific example 1, the busbar 1 is formed from a flat plate-shaped busbar body 10, and the first spring portion 14b and the second spring portion 14c, which serve as tolerance absorption structures, are provided on the first terminal connector 11, which is the central portion of the busbar body 10 removed. As a result, this busbar 1 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Moreover, in this specific example 1, the busbar 1 has the tolerance absorption structure (first spring portion 14b and second spring portion 14c) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest, so it can suppress its own heat generation and reduce the size of the heat-resistant structure (i.e., the cross-sectional area of ​​the central portion of the busbar body 10).

[0028] In addition, in the busbar 1 of this specific example 1, the second spring portion 14c is not required, and in this case, the function of absorbing the displacement of the electrode terminal BCa by the second spring portion 14c may be assigned to the first spring portion 14b.

[0029] [Specific Example 2] Reference numeral 2 in Figure 5 indicates a busbar of specific example 2 in this embodiment. This busbar 2 comprises a busbar body 20 formed from a conductive material such as metal into a rectangular flat plate shape (Figure 5). The busbar body 20 is divided into a first terminal connector 21 to be welded to the first electrode terminal BCa of one battery cell BC, and a second terminal connector 22 to be welded to the second electrode terminal BCa of the other battery cell BC (Figure 5).

[0030] In this busbar body 20, a rectangular, flat first terminal connector 21 is provided with a through hole 23 and a flexible portion 24. The flexible portion 24 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and a rectangular, flat second terminal connector 22 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like, in the same way as in conventional designs. Therefore, the through hole 23 is superimposed on the first electrode terminal BCa, exposing it. The through hole 23 is formed in a circular or square shape larger than the first electrode terminal BCa, exposing the entire flat surface (welded surface) of the first electrode terminal BCa. The through hole 23 shown here is formed in a circular shape. The second terminal connector 22 may also be provided with a through hole for welding.

[0031] The flexible portion 24 has a terminal welding portion 24a that is welded to the first electrode terminal BCa exposed through the through hole 23, and a spring portion 24b provided between the terminal welding portion 24a and the fixed end on the outer peripheral edge side of the through hole 23, which is elastically deformable in its own protruding direction and the opposite direction (Figure 5).

[0032] This flexible portion 24 is formed in a cantilever shape, projecting from the outer edge of the through hole 23 toward the center of the hole in the direction of arrangement of the multiple battery cells BC (Figure 5). The terminal welding portion 24a is provided at the free end of the flexible portion 24 (Figure 5).

[0033] This flexible portion 24 is formed in the same shape as the flexible portion 14 of Specific Example 1. Therefore, this flexible portion 24 has a flat spring portion (hereinafter referred to as the "second spring portion") 24c that protrudes from the outer peripheral edge of the through hole 23 toward the center of the hole in the direction of arrangement of the multiple battery cells BC (Figure 5). This second spring portion 24c is deformed by bending in a direction perpendicular to the plane of the first terminal connector 21 (the plane of the first electrode terminal BCa). The spring portion shown here (hereinafter referred to as the "first spring portion") 24b is formed in a V-shape or U-shape by raising the protruding end of the second spring portion 24c toward the opposite side from the first electrode terminal BCa side, and then folding back toward the first electrode terminal BCa side (Figure 5). This first spring portion 24b is deformed by bending in the direction of arrangement of the multiple battery cells BC. Furthermore, the terminal weld portion 24a is folded back towards the first electrode terminal BCa side of the first spring portion 24b, and protrudes toward the center of the through hole 23 in the direction of arrangement of the multiple battery cells BC (Figure 5). The terminal weld portion 24a shown here is formed in the shape of a rectangular flat plate parallel to the plane (welding surface) of the first electrode terminal BCa.

[0034] In this first terminal connector 21, a pair of flexible portions 24 are provided with their protruding directions facing opposite directions (Figure 5). This pair of flexible portions 24 are arranged in the direction of the arrangement of the multiple battery cells BC.

[0035] In this specific example 2, even if the position of the first electrode terminal BCa and the second electrode terminal BCa shifts within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC during use of the battery module BM, the busbar 2 can absorb the displacement of the electrode terminal BCa with the first spring portion 24b and the second spring portion 24c, thereby allowing the busbar 2 to follow the displacement of the electrode terminal BCa within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC. Furthermore, in this specific example 2, even if the terminal pitch shifts within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC during use of the battery module BM, the busbar 2 can absorb the displacement of the terminal pitch with the first spring portion 24b, thereby allowing the busbar 2 to follow the displacement of the cell pitch within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC.

[0036] Furthermore, in this specific example 2, the busbar 2 is formed from a flat plate-shaped busbar body 20, and the first spring portion 24b and the second spring portion 24c, which serve as tolerance absorption structures, are provided on the first terminal connector 21, which is formed by removing the central portion of the busbar body 20. As a result, this busbar 2 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Moreover, in this specific example 2, the busbar 2 has tolerance absorption structures (first spring portion 24b and second spring portion 24c) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest, thus suppressing its own heat generation and enabling miniaturization of the heat-resistant structure (i.e., the cross-sectional area of ​​the central portion of the busbar body 20).

[0037] In addition, in the busbar 2 of this specific example 2, the second spring portion 24c is not required, and in this case, the function of absorbing the displacement of the electrode terminal BCa by the second spring portion 24c may be assigned to the first spring portion 24b.

[0038] [Specific Example 3] Reference numeral 3 in Figure 6 indicates a busbar of specific example 3 in this embodiment. This busbar 3 comprises a busbar body 30 formed from a conductive material such as metal into a rectangular flat plate shape (Figure 6). The busbar body 30 is divided into a first terminal connector 31 to be welded to the first electrode terminal BCa of one battery cell BC, and a second terminal connector 32 to be welded to the second electrode terminal BCa of the other battery cell BC (Figure 6).

[0039] In this busbar body 30, a rectangular flat plate-shaped first terminal connector 31 is provided with a through hole (hereinafter referred to as the "first through hole") 33 and a flexible portion (hereinafter referred to as the "first flexible portion") 34, and the first flexible portion 34 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and a rectangular flat plate-shaped second terminal connector 32 is provided with a through hole (hereinafter referred to as the "second through hole") 35 and a flexible portion (hereinafter referred to as the "second flexible portion") 36, and the second flexible portion 36 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like (Figure 6).

[0040] The first through-hole 33 is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The first through-hole 33 is formed in a circular or rectangular shape larger than the first electrode terminal BCa, exposing the entire flat surface (welding surface) of the first electrode terminal BCa. Similarly, the second through-hole 35 is superimposed on the second electrode terminal BCa, exposing the second electrode terminal BCa. The second through-hole 35 is formed in a circular or rectangular shape larger than the second electrode terminal BCa, exposing the entire flat surface (welding surface) of the second electrode terminal BCa. The first through-hole 33 and the second through-hole 35 shown here are formed in a circular shape.

[0041] The first flexible portion 34 has a terminal welding portion 34a that is welded to the first electrode terminal BCa exposed from the first through hole 33, and a spring portion 34b provided between the terminal welding portion 34a and the fixed end on the outer peripheral edge side of the first through hole 33, which is elastically deformable in its own protruding direction and the opposite direction (Figure 6).

[0042] The first flexible portion 34 is formed in a cantilever shape, projecting from the outer edge of the first through-hole 33 toward the center of the hole in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figure 6). The terminal welding portion 34a is provided at the free end of the first flexible portion 34 and welded to the first electrode terminal BCa (Figure 6).

[0043] This first flexible portion 34 is formed in the same shape as the flexible portion 14 of Specific Example 1 and is positioned in the same location as the flexible portion 14 of Specific Example 1. Therefore, this first flexible portion 34 has a flat spring portion (hereinafter referred to as the "second spring portion") 34c that protrudes from the outer peripheral edge of the first through hole 33 toward the center of the hole in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figure 6). This second spring portion 34c is deformed by bending in a direction perpendicular to the plane of the first terminal connector 31 (the plane of the first electrode terminal BCa). The spring portion shown here (hereinafter referred to as the "first spring portion") 34b is formed in a V-shape or U-shape by raising the protruding end of the second spring portion 34c toward the opposite side from the first electrode terminal BCa side and folding back toward the first electrode terminal BCa side (Figure 6). This first spring portion 34b is deformed by bending in a direction perpendicular to the arrangement direction of the multiple battery cells BC. Furthermore, the terminal welding portion 34a, at the end where it is folded back toward the first electrode terminal BCa side of the first spring portion 34b, protrudes toward the center of the first through hole 33 in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figure 6). The terminal welding portion 34a shown here is formed in the shape of a rectangular flat plate parallel to the plane (welding surface) of the first electrode terminal BCa.

[0044] In the first terminal connector 31, a pair of first flexible portions 34 are provided with their protruding directions facing opposite directions (Figure 6). This pair of first flexible portions 34 are arranged in a direction perpendicular to the arrangement direction of the multiple battery cells BC.

[0045] The second flexible portion 36 has a terminal welding portion 36a that is welded to the second electrode terminal BCa exposed from the second through hole 35, and a spring portion 36b provided between the terminal welding portion 36a and the fixed end on the outer peripheral edge side of the second through hole 35, which is elastically deformable in its own protruding direction and the opposite direction (Figure 6).

[0046] This second flexible portion 36 is formed in a cantilever shape, projecting from the outer edge of the second through-hole 35 toward the center of the hole in the direction of arrangement of the multiple battery cells BC (Figure 6). The terminal welding portion 36a is provided at the free end of the second flexible portion 36 and welded to the second electrode terminal BCa (Figure 6).

[0047] This second flexible portion 36 is formed in the same shape as the flexible portion 24 of Specific Example 2 and is positioned in the same location as the flexible portion 24 of Specific Example 2. Therefore, this second flexible portion 36 has a flat spring portion (hereinafter referred to as "second spring portion") 36c that protrudes from the outer peripheral edge of the second through hole 35 toward the center of the hole in the direction of arrangement of the multiple battery cells BC (Figure 6). This second spring portion 36c is deformed by bending in a direction perpendicular to the plane of the second terminal connector 32 (the plane of the second electrode terminal BCa). The spring portion shown here (hereinafter referred to as "first spring portion") 36b is formed in a V-shape or U-shape by raising the protruding end of the second spring portion 36c toward the opposite side from the second electrode terminal BCa side and folding back toward the second electrode terminal BCa side (Figure 6). This first spring portion 36b is deformed by bending in the direction of arrangement of the multiple battery cells BC. Furthermore, the terminal weld portion 36a is folded back towards the second electrode terminal BCa side of its first spring portion 36b, and protrudes toward the center of the second through hole 35 in the direction of arrangement of the multiple battery cells BC (Figure 6). The terminal weld portion 36a shown here is formed in the shape of a rectangular flat plate parallel to the plane (welding surface) of the second electrode terminal BCa.

[0048] In the second terminal connector 32, a pair of second flexible portions 36 are provided with their protruding directions facing opposite directions (Figure 6). This pair of second flexible portions 36 are arranged in the direction of the arrangement of the multiple battery cells BC.

[0049] In this specific example 3, even if the position of the first electrode terminal BCa shifts within the design tolerance range due to thermal expansion or contraction of one battery cell BC during the use of the battery module BM, the busbar 3 can absorb this shift in position of the first electrode terminal BCa by the first spring portion 34b and the second spring portion 34c of the first flexible portion 34, thereby allowing the busbar 3 to follow the shift in position of the first electrode terminal BCa within the design tolerance range due to thermal expansion or contraction of one battery cell BC. Furthermore, in this specific example 3, even if the position of the second electrode terminal BCa shifts within the design tolerance range due to thermal expansion or contraction of the other battery cell BC during the use of the battery module BM, the busbar 3 can absorb this shift in position of the second electrode terminal BCa by the first spring portion 36b and the second spring portion 36c of the second flexible portion 36, thereby allowing the busbar 3 to follow the shift in position of the second electrode terminal BCa within the design tolerance range due to thermal expansion or contraction of the other battery cell BC.

[0050] Furthermore, in this specific example 3, even if the terminal pitch shifts within the design tolerance range due to thermal expansion or contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 3 can absorb the shift in terminal pitch with the first spring portion 36b of the second flexible portion 36, thereby allowing it to follow the shift in cell pitch within the design tolerance range caused by thermal expansion or contraction of one battery cell BC or the other battery cell BC.

[0051] Furthermore, in this specific example 3, the busbar 3 is formed by shaping the busbar body 30 into a flat plate, and the first spring portion 34b and the second spring portion 34c of the first flexible portion 34, which serve as a tolerance absorption structure, are provided on the first terminal connector 31, which is formed by removing the central portion of the busbar body 30, and the first spring portion 36b and the second spring portion 36c of the second flexible portion 36, which serve as a tolerance absorption structure, are provided on the second terminal connector 32, which is formed by removing the central portion of the busbar body 30. As a result, this busbar 3 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, in this specific example 3, the busbar 3 is provided with a tolerance absorption structure (first spring portion 34b and second spring portion 34c of the first flexible portion 34, and first spring portion 36b and second spring portion 36c of the second flexible portion 36) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest. This allows the busbar to suppress its own heat generation and enables miniaturization of the heat-resistant structure (i.e., the cross-sectional area of ​​the central part of the busbar body 30).

[0052] In addition, in the busbar 3 of this specific example 3, the second spring sections 34c and 36c do not need to be provided. In this case, the function of absorbing the displacement of the electrode terminal BCa caused by the second spring sections 34c and 36c may be assigned to the first spring sections 34b and 36b.

[0053] [Specific Example 4] Reference numeral 4 in Figure 7 indicates a busbar of specific example 4 in this embodiment. This busbar 4 comprises a busbar body 40 formed from a conductive material such as metal into a rectangular flat plate shape (Figure 7). The busbar body 40 is divided into a first terminal connector 41 to be welded to the first electrode terminal BCa of one battery cell BC, and a second terminal connector 42 to be welded to the second electrode terminal BCa of the other battery cell BC (Figure 7).

[0054] In this busbar body 40, a rectangular, flat first terminal connector 41 is provided with a through hole 43 and a flexible portion 44. The flexible portion 44 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and a rectangular, flat second terminal connector 42 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like, in the same way as conventional designs. Therefore, the through hole 43 is superimposed on the first electrode terminal BCa, exposing it. The through hole 43 is formed in a circular shape larger than the first electrode terminal BCa, exposing the entire flat surface (welded surface) of the first electrode terminal BCa. The second terminal connector 42 may also be provided with a through hole for welding. The second terminal connector 42 may also be provided with a through hole 43 and a flexible portion 44 similar to those of the first terminal connector 41.

[0055] The flexible portion 44 has a terminal welding portion 44a that is welded to the first electrode terminal BCa exposed through the through hole 43, and a spring portion 44b provided between the terminal welding portion 44a and the fixed end on the outer peripheral edge side of the through hole 43, which is elastically deformable in its own protruding direction and the opposite direction (Figure 7).

[0056] The flexible portion 44 is formed in a cantilever shape, projecting from the outer edge of the through hole 43 toward the center of the hole (Figure 7). Multiple flexible portions 44 are provided at equal intervals around the circumference of the through hole 43 (Figure 7). The terminal welding portion 44a is provided at the free end of the flexible portion 44 (Figure 7). For example, one of the multiple flexible portions 44 is formed in a cantilever shape, projecting from the outer edge of the through hole 43 toward the center of the hole in a direction perpendicular to the arrangement direction of the multiple battery cells BC. In the first terminal connector 41, multiple flexible portions 44 are provided at equal intervals around the circumference of the through hole 43. The first terminal connector 41 shown here has five flexible portions 44.

[0057] This flexible portion 44 is formed in the same shape as the flexible portion 14 in Specific Example 1 and the flexible portion 24 in Specific Example 2. Therefore, this flexible portion 44 has a flat spring portion (hereinafter referred to as the "second spring portion") 44c that protrudes from the outer peripheral edge of the through hole 43 toward the center of the hole (Figure 7). This second spring portion 44c is deformed by bending in a direction perpendicular to the plane of the first terminal connector 41 (the plane of the first electrode terminal BCa). The spring portion shown here (hereinafter referred to as the "first spring portion") 44b is formed in a V-shape or U-shape by raising the protruding end of the second spring portion 44c toward the opposite side of the first electrode terminal BCa, and then folding back toward the first electrode terminal BCa (Figure 7). This first spring portion 44b is deformed by bending in the direction of protrusion from the outer peripheral edge of the through hole 43 in the flexible portion 44 and in the opposite direction. Furthermore, the terminal weld portion 44a is folded back towards the first electrode terminal BCa side of its first spring portion 44b, and protrudes toward the center of the through hole 43 (Figure 7). The terminal weld portion 44a shown here is formed in the shape of a rectangular flat plate parallel to the plane (welding surface) of the first electrode terminal BCa.

[0058] In this specific example 4, even if the positions of the first electrode terminal BCa and the second electrode terminal BCa shift within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC during use of the battery module BM, the busbar 4 can absorb the displacement of the electrode terminal BCa with the first spring portion 44b and the second spring portion 44c of each flexible portion 44, thereby allowing the busbar 4 to follow the displacement of the electrode terminal BCa within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC. Furthermore, in this specific example 4, even if the terminal pitch shifts within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC during use of the battery module BM, the busbar 4 can absorb the displacement of the terminal pitch with the first spring portion 24b of each flexible portion 44, thereby allowing the busbar 4 to follow the displacement of the cell pitch within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC.

[0059] Furthermore, in this specific example 4, the busbar 4 is formed by shaping the busbar body 40 into a flat plate, and then providing the first spring portion 44b and the second spring portion 44c of each flexible portion 44, which form a tolerance absorption structure, to the first terminal connector 41, which is the central portion of the busbar body 40 removed. As a result, this busbar 4 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Moreover, in this specific example 4, the busbar 4 is provided with a tolerance absorption structure (the first spring portion 44b and the second spring portion 44c of each flexible portion 44) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest, thereby suppressing its own heat generation and enabling miniaturization of the heat-resistant structure (i.e., the cross-sectional area of ​​the central portion of the busbar body 40).

[0060] In addition, in the busbar 4 of this specific example 4, the second spring portion 44c is not required, and in this case, the function of absorbing the displacement of the electrode terminal BCa by the second spring portion 44c may be assigned to the first spring portion 44b.

[0061] [Specific Example 5] Reference numeral 5 in Figure 8 indicates a busbar of specific example 5 in this embodiment. This busbar 5 comprises a busbar body 50 formed from a conductive material such as metal into a rectangular flat plate shape (Figure 8). The busbar body 50 is divided into a first terminal connector 51 to be welded to the first electrode terminal BCa of one battery cell BC, and a second terminal connector 52 to be welded to the second electrode terminal BCa of the other battery cell BC (Figure 8).

[0062] In this busbar body 50, a rectangular, flat first terminal connector 51 is provided with a through hole 53 and a flexible portion 54. The flexible portion 54 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and a rectangular, flat second terminal connector 52 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like, in the same way as in conventional designs. Therefore, the through hole 53 is superimposed on the first electrode terminal BCa, exposing it. The through hole 53 is formed in a circular or square shape larger than the first electrode terminal BCa, exposing the entire flat surface (welded surface) of the first electrode terminal BCa. The through hole 53 shown here is formed in a circular shape. The second terminal connector 52 may also be provided with a through hole for welding.

[0063] The flexible portion 54 has a terminal welding portion 54a that is welded to the first electrode terminal BCa exposed through the through hole 53, and a spring portion 54b provided between the terminal welding portion 54a and the fixed end on the outer peripheral edge side of the through hole 53, which is elastically deformable in its own protruding direction and the opposite direction (Figure 8).

[0064] The flexible portion 54 is formed in a cantilevered beam shape, projecting toward the center of the through hole 53 from two opposing points on the outer edge of the through hole 53 in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figure 8). The terminal weld portion 54a is positioned in the center of the flexible portion 54 and in the center of the through hole 53 (Figure 8). The spring portion 54b is provided between the terminal weld portion 54a and one fixed end, and between the terminal weld portion 54a and the other fixed end (Figure 8).

[0065] The flexible portion 54 has flat spring portions (hereinafter referred to as "second spring portions") 54c that protrude toward the center of the through hole 53 from two opposite locations on the outer edge of the through hole 53 in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figure 8). Each second spring portion 54c is deformed by bending in a direction perpendicular to the plane of the first terminal connector 51 (the plane of the first electrode terminal BCa). The spring portion shown here (hereinafter referred to as "first spring portion") 54b is formed in a V-shape or U-shape by raising the end of the protrusion from the second spring portion 54c toward the opposite side from the first electrode terminal BCa side, and then folding back toward the first electrode terminal BCa side (Figure 8). Each first spring portion 54b is deformed by bending in a direction perpendicular to the arrangement direction of the multiple battery cells BC. Furthermore, the terminal weld portion 54a connects the ends of each first spring portion 54b that have been folded back towards the first electrode terminal BCa side (Figure 8). The terminal weld portion 54a shown here is formed in a disc shape parallel to the plane (welding surface) of the first electrode terminal BCa.

[0066] In this specific example 5, even if the positions of the first electrode terminal BCa and the second electrode terminal BCa shift within the design tolerance range due to thermal expansion or contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 5 can absorb the displacement of the electrode terminal BCa with a pair of first spring parts 54b and a pair of second spring parts 54c, thereby allowing the bus bar 5 to follow the displacement of the electrode terminal BCa within the design tolerance range due to thermal expansion or contraction of one battery cell BC or the other battery cell BC.

[0067] Furthermore, in this specific example 5, the busbar 5 is formed from a flat plate-shaped busbar body 50, and the first spring portion 54b and the second spring portion 54c, which form a tolerance absorption structure, are provided on the first terminal connector 51, which is the central portion of the busbar body 50 removed. As a result, this busbar 5 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Moreover, in this specific example 5, the busbar 5 has a tolerance absorption structure (first spring portion 54b and second spring portion 54c) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest, so it can suppress its own heat generation and reduce the size of the heat-resistant structure (i.e., the cross-sectional area of ​​the central portion of the busbar body 50).

[0068] In addition, in the bus bar 5 of this specific example 5, the second spring portion 54c is not required, and in this case, the function of absorbing the displacement of the electrode terminal BCa by the second spring portion 54c may be assigned to the first spring portion 54b.

[0069] [Specific Example 6] Reference numeral 6 in Figure 9 indicates a busbar of specific example 6 in this embodiment. This busbar 6 comprises a busbar body 60 formed from a conductive material such as metal into a rectangular flat plate shape (Figure 9). The busbar body 60 is divided into a first terminal connector 61 to be welded to the first electrode terminal BCa of one battery cell BC, and a second terminal connector 62 to be welded to the second electrode terminal BCa of the other battery cell BC (Figure 9).

[0070] In this busbar body 60, a rectangular flat plate-shaped first terminal connector 61 is provided with a through hole 63 and a flexible portion 64. The flexible portion 64 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and a rectangular flat plate-shaped second terminal connector 62 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like, in the same way as conventional designs. Therefore, the through hole 63 is superimposed on the first electrode terminal BCa, exposing it. The through hole 63 is formed in a circular or square shape larger than the first electrode terminal BCa, exposing the entire flat surface (welded surface) of the first electrode terminal BCa. The through hole 63 shown here is formed in a circular shape. The second terminal connector 62 may also be provided with a through hole for welding.

[0071] The flexible portion 64 has a terminal welding portion 64a that is welded to the first electrode terminal BCa exposed through the through hole 63, and a spring portion 64b provided between the terminal welding portion 64a and the fixed end on the outer peripheral edge side of the through hole 63, which is elastically deformable in its own protruding direction and the opposite direction (Figure 9).

[0072] The flexible portion 64 is formed in a cantilevered beam shape, projecting toward the center of the through hole 63 from two opposing points on the outer edge of the through hole 63 in the direction of arrangement of the multiple battery cells BC (Figure 9). The terminal welding portion 64a is positioned in the center of the flexible portion 64 and in the center of the through hole 63 (Figure 9). The spring portion 64b is provided between the terminal welding portion 64a and one fixed end, and between the terminal welding portion 64a and the other fixed end (Figure 9).

[0073] This flexible portion 64 is formed in the same shape as the flexible portion 54 of Specific Example 5. Therefore, this flexible portion 64 has flat spring portions (hereinafter referred to as "second spring portions") 64c that protrude toward the center of the through hole 63 from two opposite locations on the outer edge of the through hole 63 in the direction of arrangement of the multiple battery cells BC (Figure 9). Each second spring portion 64c is deformed by bending in a direction perpendicular to the plane of the first terminal connector 61 (the plane of the first electrode terminal BCa). The spring portion shown here (hereinafter referred to as "first spring portion") 64b is formed in a V-shape or U-shape by raising the end of the protrusion of the second spring portion 64c toward the opposite side from the first electrode terminal BCa side, and then folding back toward the first electrode terminal BCa side (Figure 9). Each first spring portion 64b is deformed by bending in the direction of arrangement of the multiple battery cells BC. Furthermore, the terminal weld portion 64a connects the ends of each first spring portion 64b that have been folded back towards the first electrode terminal BCa side (Figure 9). The terminal weld portion 64a shown here is formed in a disc shape parallel to the plane (welding surface) of the first electrode terminal BCa.

[0074] In this specific example 6, even if the position of the first electrode terminal BCa and the second electrode terminal BCa shifts within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC during use of the battery module BM, the busbar 6 can absorb the displacement of the electrode terminal BCa with a pair of first spring parts 64b and a pair of second spring parts 64c, thereby allowing the busbar 6 to follow the displacement of the electrode terminal BCa within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC. Furthermore, in this specific example 6, even if the pitch between terminals shifts within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC during use of the battery module BM, the busbar 6 can absorb the displacement of the pitch between terminals with a pair of first spring parts 64b, thereby allowing the busbar 6 to follow the displacement of the pitch between cells within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC.

[0075] Furthermore, in this specific example 6, the busbar 6 is formed from a flat plate-shaped busbar body 60, and the first spring portion 64b and the second spring portion 64c, which form a tolerance absorption structure, are provided on the first terminal connector 61, which is the central portion of the busbar body 60 removed. As a result, this busbar 6 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Moreover, in this specific example 6, the busbar 6 has a tolerance absorption structure (first spring portion 64b and second spring portion 64c) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest, so it can suppress its own heat generation and reduce the size of the heat-resistant structure (i.e., the cross-sectional area of ​​the central portion of the busbar body 60).

[0076] In addition, in the bus bar 6 of this specific example 6, the second spring portion 64c is not required, and in this case, the function of absorbing the displacement of the electrode terminal BCa by the second spring portion 64c may be assigned to the first spring portion 64b.

[0077] [Specific Example 7] Reference numeral 7 in Figure 10 indicates a busbar of specific example 7 in this embodiment. This busbar 7 comprises a busbar body 70 formed from a conductive material such as metal into a rectangular flat plate shape (Figure 10). The busbar body 70 is divided into a first terminal connector 71 which is to be welded to the first electrode terminal BCa of one battery cell BC, and a second terminal connector 72 which is to be welded to the second electrode terminal BCa of the other battery cell BC (Figure 10).

[0078] In this busbar body 30, a rectangular flat plate-shaped first terminal connector 71 is provided with a through hole (hereinafter referred to as the "first through hole") 73 and a flexible portion (hereinafter referred to as the "first flexible portion") 74, and the first flexible portion 74 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and a rectangular flat plate-shaped second terminal connector 72 is provided with a through hole (hereinafter referred to as the "second through hole") 75 and a flexible portion (hereinafter referred to as the "second flexible portion") 76, and the second flexible portion 76 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like (Figure 10).

[0079] The first through-hole 73 is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The first through-hole 73 is formed in a circular or rectangular shape larger than the first electrode terminal BCa, exposing the entire flat surface (welding surface) of the first electrode terminal BCa. Similarly, the second through-hole 75 is superimposed on the second electrode terminal BCa, exposing the second electrode terminal BCa. The second through-hole 75 is formed in a circular or rectangular shape larger than the second electrode terminal BCa, exposing the entire flat surface (welding surface) of the second electrode terminal BCa. The first through-hole 73 and the second through-hole 75 shown here are formed in a circular shape.

[0080] The first flexible portion 74 has a terminal welding portion 74a that is welded to the first electrode terminal BCa exposed from the first through hole 73, and a spring portion 74b provided between the terminal welding portion 74a and the fixed end on the outer peripheral edge side of the first through hole 73, which is elastically deformable in its own protruding direction and the opposite direction (Figure 10).

[0081] The first flexible portion 74 is formed in a cantilevered beam shape, projecting toward the center of the first through-hole 73 from two opposing points on the outer edge of the first through-hole 73 in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figure 10). The terminal welding portion 74a is positioned in the center of the first flexible portion 74 and in the center of the first through-hole 73, and is welded to the first electrode terminal BCa (Figure 10). The spring portion 74b is provided between the terminal welding portion 74a and one fixed end, and between the terminal welding portion 74a and the other fixed end (Figure 10).

[0082] This first flexible portion 74 is formed in the same shape as the flexible portion 54 of Specific Example 5 and is positioned in the same location as the flexible portion 54 of Specific Example 5. Therefore, this first flexible portion 74 has flat spring portions (hereinafter referred to as "second spring portions") 74c that protrude toward the center of the hole from two opposite locations on the outer edge of the first through hole 73 in a direction perpendicular to the arrangement direction of the multiple battery cells BC (Figure 10). Each second spring portion 74c is deformed by bending in a direction perpendicular to the plane of the first terminal connector 71 (the plane of the first electrode terminal BCa). The spring portion (hereinafter referred to as "first spring portion") 74b shown here is formed in a V-shape or U-shape by raising the end of the protruding part of the second spring portion 74c toward the opposite side from the first electrode terminal BCa side and folding back toward the first electrode terminal BCa side (Figure 10). Each first spring portion 74b is deformed by bending in a direction perpendicular to the arrangement direction of the multiple battery cells BC. The terminal welding portion 74a connects the ends of each first spring portion 74b that are folded back towards the first electrode terminal BCa side (Figure 10). The terminal welding portion 74a shown here is formed in a disc shape parallel to the plane (welding surface) of the first electrode terminal BCa.

[0083] The second flexible portion 76 has a terminal welding portion 76a that is welded to the second electrode terminal BCa exposed from the second through hole 75, and a spring portion 76b provided between the terminal welding portion 76a and the fixed end on the outer peripheral edge side of the second through hole 75, which is elastically deformable in its own protruding direction and the opposite direction (Figure 10).

[0084] The second flexible portion 76 is formed in a cantilevered beam shape, projecting toward the center of the second through-hole 75 from two opposing points on the outer edge of the second through-hole 75 in the direction of arrangement of the multiple battery cells BC (Figure 10). The terminal welding portion 76a is positioned in the center of the second flexible portion 76 and in the center of the second through-hole 75, and is welded to the second electrode terminal BCa (Figure 10). The spring portion 76b is provided between the terminal welding portion 76a and one fixed end, and between the terminal welding portion 76a and the other fixed end (Figure 10).

[0085] This second flexible portion 76 is formed in the same shape as the flexible portion 64 of Specific Example 6 and is positioned in the same location as the flexible portion 64 of Specific Example 6. Therefore, this second flexible portion 76 has flat spring portions (hereinafter referred to as "second spring portions") 76c that protrude toward the center of the hole from two opposite locations on the outer edge of the second through hole 75 in the direction of arrangement of the multiple battery cells BC (Figure 10). Each second spring portion 76c is deformed by bending in a direction perpendicular to the plane of the second terminal connector 72 (the plane of the second electrode terminal BCa). The spring portion shown here (hereinafter referred to as "first spring portion") 76b is formed in a V-shape or U-shape by raising the end of the protruding part of the second spring portion 76c toward the opposite side from the second electrode terminal BCa side and folding back toward the second electrode terminal BCa side (Figure 10). Each first spring portion 76b is deformed by bending in the direction of the arrangement of the multiple battery cells BC. The terminal welding portion 76a connects the ends of each first spring portion 76b that are folded back towards the second electrode terminal BCa side (Figure 10). The terminal welding portion 76a shown here is formed in a disc shape parallel to the plane (welding surface) of the second electrode terminal BCa.

[0086] In this specific example 7, even if the position of the first electrode terminal BCa shifts within the design tolerance range due to thermal expansion or contraction of one battery cell BC during the use of the battery module BM, the busbar 7 can absorb this shift in position of the first electrode terminal BCa by the first spring portion 74b and the second spring portion 74c of the first flexible portion 74, thereby allowing the busbar 7 to follow the shift in position of the first electrode terminal BCa within the design tolerance range due to thermal expansion or contraction of one battery cell BC. Furthermore, in this specific example 7, even if the position of the second electrode terminal BCa shifts within the design tolerance range due to thermal expansion or contraction of the other battery cell BC during the use of the battery module BM, the busbar 7 can absorb this shift in position of the second electrode terminal BCa by the first spring portion 76b and the second spring portion 76c of the second flexible portion 76, thereby allowing the busbar 7 to follow the shift in position of the second electrode terminal BCa within the design tolerance range due to thermal expansion or contraction of the other battery cell BC.

[0087] Furthermore, in this specific example 7, even if the terminal pitch shifts within the design tolerance range due to thermal expansion or contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 7 can absorb the shift in terminal pitch with the first spring portion 76b of the second flexible portion 76, thereby allowing it to follow the shift in cell pitch within the design tolerance range caused by thermal expansion or contraction of one battery cell BC or the other battery cell BC.

[0088] Furthermore, in this specific example 7, the busbar 7 is formed by shaping the busbar body 70 into a flat plate, and then providing the first spring portion 74b and the second spring portion 74c of the first flexible portion 74, which serves as a tolerance absorption structure, on the first terminal connector 71, which is formed by removing the central portion of the busbar body 70, and providing the first spring portion 76b and the second spring portion 76c of the second flexible portion 76, which serves as a tolerance absorption structure, on the second terminal connector 72, which is formed by removing the central portion of the busbar body 70. As a result, this busbar 7 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, in this specific example 7, the busbar 7 is provided with tolerance absorption structures (first spring portion 74b and second spring portion 74c of the first flexible portion 74, and first spring portion 76b and second spring portion 76c of the second flexible portion 76) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation from the battery cell BC is highest. This allows the busbar to suppress its own heat generation and enables miniaturization of the heat-resistant structure (i.e., the cross-sectional area of ​​the central part of the busbar body 70).

[0089] In addition, in the busbar 7 of this specific example 7, the second spring portions 74c and 76c do not need to be provided. In this case, the function of absorbing the displacement of the electrode terminal BCa caused by the second spring portions 74c and 76c may be assigned to the first spring portions 74b and 76b.

[0090] [Transformed form] One modified form of the busbar according to the present invention will be explained with reference to Figures 12 to 14.

[0091] This modified busbar comprises a first busbar body formed in a flat plate shape. This first busbar body is positioned between two adjacent battery cells BC. Furthermore, this modified busbar comprises a second busbar body that is physically and electrically connected to the first busbar body.

[0092] The first busbar body is divided into two parts: a first terminal connector having a notch or through hole that exposes the first electrode terminal BCa of one battery cell BC, and to which the first electrode terminal BCa is electrically connected via the second busbar body; and a second terminal connector that is to be welded to the second electrode terminal BCa of the other battery cell BC.

[0093] The second busbar body 120 is positioned in the notch or through hole of the first terminal connector of the first busbar body and includes a terminal welding portion for welding to the first electrode terminal BCa, a first busbar welding portion for welding to the first terminal connector, a second busbar welding portion for welding to the first terminal connector, a first spring portion provided between the terminal welding portion and the first busbar welding portion and elastically deformable in the direction of arrangement of the terminal welding portion and the first busbar welding portion and in the opposite direction, a second spring portion provided between the terminal welding portion and the second busbar welding portion and elastically deformable in the direction of arrangement of the terminal welding portion and the second busbar welding portion and in the opposite direction, and a circuit conductor connection portion for physically and electrically connecting to a circuit conductor to be electrically connected to the battery monitoring unit.

[0094] This modified busbar comprises a first busbar body and a second busbar body of the same shape, thereby allowing the first and second spring sections of the second busbar body to function as tolerance-absorbing structures. For example, even if the spacing between the electrode terminals BCa of two adjacent battery cells BC (the so-called inter-terminal pitch) is within the design tolerance range, this busbar can be welded to each electrode terminal BCa by absorbing the deviation in the inter-terminal pitch with the first and second spring sections. Furthermore, even if the terminal pitch shifts within the design tolerance range or the position of the electrode terminal BCa shifts within the design tolerance range due to thermal expansion or contraction of the battery cell BC during use of the battery module BM, this busbar can absorb the shift in terminal pitch and the position of the electrode terminal BCa within the design tolerance range due to thermal expansion or contraction of the battery cell BC with the first and second spring sections, thereby allowing it to follow the shift in cell pitch within the design tolerance range due to thermal expansion or contraction of the battery cell BC, and to follow the position of the electrode terminal BCa within the design tolerance range due to thermal expansion or contraction of the battery cell BC.

[0095] Furthermore, in this modified busbar configuration, the first and second spring sections (tolerance absorption structure) of the second busbar body are provided in a location that avoids the central portion between the first and second terminal connectors of the first busbar body. This allows for a heat-resistant structure to be provided in the central portion without being constrained by the tolerance absorption structure. Moreover, in this modified busbar configuration, the first and second spring sections (tolerance absorption structure) are provided at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest. This suppresses heat generation in the first busbar body and allows for miniaturization of the heat-resistant structure (i.e., the cross-sectional area of ​​the central portion of the first busbar body).

[0096] The following describes specific examples of this modified form of the bus bar.

[0097] [Specific examples] Reference numeral 101 in Figure 12 indicates a busbar of specific example 1 in this modified form. This busbar 101 comprises a first busbar body 110 formed in the shape of a flat plate from a conductive material such as metal, and a second busbar body 120 that is physically and electrically connected to the first busbar body 110 (Figure 12).

[0098] The first busbar body 110 is formed into a rectangular flat plate shape. This first busbar body 110 is divided into a rectangular flat plate first terminal connector 111 to which the first electrode terminal BCa of one battery cell BC is electrically connected via the second busbar body 120, and a rectangular flat plate second terminal connector 112 to which the second electrode terminal BCa of the other battery cell BC is to be welded (Figure 12). In this specific example 1, the first terminal connector 111 has a notch 111a that exposes the first electrode terminal BCa.

[0099] In this first busbar body 110, the second busbar body 120 is assembled to the first terminal connector 111, and a part of the second busbar body 120, which is positioned in the notch 111a, is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and the second terminal connector 112 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like, in the same way as in the conventional method. Therefore, the notch 111a is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The notch 111a is formed in the shape of a rectangle larger than the first electrode terminal BCa, exposing the entire plane (welded surface) of the first electrode terminal BCa. The notch 111a shown here is cut out in a rectangular shape from the side of the first terminal connector 111 in the direction of the arrangement of the multiple battery cells BC toward the second terminal connector 112. Furthermore, the second terminal connector 112 may be provided with a through hole for welding.

[0100] The second busbar body 120 is positioned in the notch 111a of the first terminal connector 111 of the first busbar body 110 and has a terminal weld portion 121 that is welded to the first electrode terminal BCa, a first busbar weld portion 122 that is welded to the first terminal connector 111, and a second busbar weld portion 123 that is welded to the first terminal connector 111 (Figure 12). Furthermore, the second busbar body 120 has a first spring portion 124 provided between the terminal weld portion 121 and the first busbar weld portion 122 and elastically deformable in the direction of alignment of the terminal weld portion 121 and the first busbar weld portion 122 and in the opposite direction, and a second spring portion 125 provided between the terminal weld portion 121 and the second busbar weld portion 123 and elastically deformable in the direction of alignment of the terminal weld portion 121 and the second busbar weld portion 123 and in the opposite direction (Figure 12). Furthermore, the second busbar body 120 has a circuit conductor connection portion 126 that is physically and electrically connected to a circuit conductor (in this case, a wiring pattern on a flexible printed circuit board) that is electrically connected to the battery monitoring unit (Figure 12).

[0101] The second busbar body 120 has its first busbar weld 122, first spring 124, terminal weld 121, second spring 125, and second busbar weld 123 arranged in that order in a line. The second busbar body 120 is connected to the first busbar body 110 with its arrangement direction oriented in the direction of the arrangement of the multiple battery cells BC or in a direction perpendicular to the direction of the arrangement of the multiple battery cells BC. The second busbar body 120 shown here has its first busbar weld 122, first spring 124, terminal weld 121, second spring 125, second busbar weld 123, and circuit conductor connection part 126 arranged in that order in a line (Figure 12). The second busbar body 120 shown here is connected to the first busbar body 110 with its arrangement direction oriented in a direction perpendicular to the direction of the arrangement of the multiple battery cells BC (Figure 12).

[0102] The second busbar body 120 is formed, for example, by bending a rectangular flat plate, and the rectangular flat plate first busbar weld portion 122 and the rectangular flat plate second busbar weld portion 123 are welded to the first terminal connector 111. In the first terminal connector 111 shown here, portions are formed on one side and the other side of the notch portion 111a in a direction perpendicular to the arrangement direction of the multiple battery cells BC. In the second busbar body 120, the first busbar weld portion 122 is welded to the portion on one side, and the second busbar weld portion 123 is welded to the portion on the other side (Figure 12).

[0103] In the first busbar weld 122, the edge on the terminal weld 121 side (i.e., the second busbar weld 123 side) is superimposed on the notch 111a. The first spring portion 124 is formed by extending upward from the edge of the first busbar weld 122 toward the side opposite to the first electrode terminal BCa, and then folding back toward the first electrode terminal BCa (Figure 12). Similarly, in the second busbar weld 123, the edge on the terminal weld 121 side (i.e., the first busbar weld 122 side) is superimposed on the notch 111a. The second spring portion 125 is formed by extending upward from the edge of the second busbar weld 123 toward the side opposite to the first electrode terminal BCa, and then folding back toward the first electrode terminal BCa (Figure 12). The first spring portion 124 and the second spring portion 125 are deformed by bending in a direction perpendicular to the arrangement direction of the multiple battery cells BC. The terminal welding portion 121 connects the respective ends of the first spring portion 124 and the second spring portion 125 that are folded back toward the first electrode terminal BCa side (Figure 12). The terminal welding portion 121 shown here is formed in a disc shape parallel to the plane (welding surface) of the first electrode terminal BCa. The circuit conductor connection portion 126 is connected to the other side of the second busbar welding portion 123 and protrudes from the first busbar body 110 (Figure 12).

[0104] In this specific example 1, even if the positions of the first electrode terminal BCa and the second electrode terminal BCa shift within the design tolerance range due to thermal expansion or contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the first spring portion 124 and the second spring portion 125 absorb the displacement of the electrode terminal BCa, thereby allowing the busbar 101 to follow the displacement of the electrode terminal BCa within the design tolerance range due to thermal expansion or contraction of one battery cell BC or the other battery cell BC.

[0105] Furthermore, in this specific example 1, the busbar 101 is formed by shaping the first busbar body 110 into a flat plate, and then attaching the second busbar body 120, which has a tolerance absorption structure (first spring portion 124 and second spring portion 125), to the first terminal connector 111, which has the central portion between the first terminal connector 111 and the second terminal connector 112 of the first busbar body 110 removed. As a result, this busbar 101 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, in this specific example 1, the busbar 101 is provided with a tolerance absorption structure (first spring portion 124 and second spring portion 125) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest. This suppresses the heat generation of the first busbar body 110, and allows for miniaturization of the heat-resistant structure (i.e., the cross-sectional area of ​​the central part of the first busbar body 110).

[0106] Incidentally, the first terminal connector 111 of the first busbar body 110 may be provided with clamping portions 111b that clamp the first busbar weld portion 122 of the second busbar body 120 from each side (Figure 13). For example, each clamping portion 111b is used to position the terminal weld portion 121 of the second busbar body 120 in the direction of arrangement of the multiple battery cells BC when welding the first busbar weld portion 122 to the first terminal connector 111.

[0107] [Specific Example 2] Reference numeral 201 in Figure 14 indicates a busbar of specific example 2 in this modified form. This busbar 201 comprises a first busbar body 210 formed in the shape of a flat plate from a conductive material such as metal, and a second busbar body 220 that is physically and electrically connected to the first busbar body 210 (Figure 14).

[0108] The first busbar body 210 is formed into a rectangular flat plate shape. This first busbar body 210 is divided into a rectangular flat plate first terminal connector 211 to which the first electrode terminal BCa of one battery cell BC is electrically connected via the second busbar body 220, and a rectangular flat plate second terminal connector 212 to which the second electrode terminal BCa of the other battery cell BC is to be welded (Figure 14). In this specific example 2, the first terminal connector 211 has a notch 211a that exposes the first electrode terminal BCa.

[0109] In this first busbar body 210, the second busbar body 220 is assembled to the first terminal connector 211, and a part of the second busbar body 220, which is positioned in the notch 211a, is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and the second terminal connector 212 is welded to the second electrode terminal BCa of the other battery cell BC by laser welding or the like, in the same way as in the conventional method. Therefore, the notch 211a is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The notch 211a is formed in a rectangle larger than the first electrode terminal BCa, exposing the entire plane (welded surface) of the first electrode terminal BCa. The notch 211a shown here is cut out in a rectangular shape from one corner on the side of the first terminal connector 211 in the direction of arrangement of the multiple battery cells BC. Furthermore, the second terminal connector 212 may be provided with a through hole for welding.

[0110] The second busbar body 220 is positioned in the notch 211a of the first terminal connector 211 of the first busbar body 210 and has a terminal weld portion 221 that is welded to the first electrode terminal BCa, a first busbar weld portion 222 that is welded to the first terminal connector 211, and a second busbar weld portion 223 that is welded to the first terminal connector 211 (Figure 14). Furthermore, the second busbar body 220 has a first spring portion 224 provided between the terminal weld portion 221 and the first busbar weld portion 222 and elastically deformable in the direction of alignment of the terminal weld portion 221 and the first busbar weld portion 222 and in the opposite direction, and a second spring portion 225 provided between the terminal weld portion 221 and the second busbar weld portion 223 and elastically deformable in the direction of alignment of the terminal weld portion 221 and the second busbar weld portion 223 and in the opposite direction (Figure 14). Furthermore, the second busbar body 220 has a circuit conductor connection portion 226 that is physically and electrically connected to a circuit conductor (in this case, a wiring pattern on a flexible printed circuit board) that is electrically connected to the battery monitoring unit (Figure 14).

[0111] The second busbar body 220 has its first busbar weld 222, first spring portion 224, and terminal weld 221 arranged in that order in the first direction, and its terminal weld 221, second spring portion 225, and second busbar weld 223 arranged in that order in the second direction perpendicular to the first direction, and is connected to the first busbar body 210 with the first direction facing the direction of arrangement of the multiple battery cells BC and the second direction facing perpendicular to the direction of arrangement of the multiple battery cells BC (Figure 14).

[0112] The second busbar body 220 is formed, for example, by bending an L-shaped flat plate, and a rectangular flat plate first busbar weld 222 on one side of the L-shape and a rectangular flat plate second busbar weld 223 on the other side of the L-shape are welded to the first terminal connector 211. In the first terminal connector 211 shown here, a portion is formed on the side of the notch 211a to the second terminal connector 212 in the direction of arrangement of the multiple battery cells BC, and on the side of the notch 111a in the direction perpendicular to the direction of arrangement of the multiple battery cells BC. In the second busbar body 120, the first busbar weld 222 is welded to the portion on the second terminal connector 212 side, and the second busbar weld 223 is welded to the portion on the side perpendicular to that direction (Figure 14).

[0113] In the first busbar weld 222, the edge on the terminal weld 221 side is superimposed on the notch 211a. The first spring portion 224 is formed by extending upward from the edge of the first busbar weld 222 toward the side opposite to the first electrode terminal BCa, and then folding back toward the first electrode terminal BCa at the end of the extended portion (Figure 14). This first spring portion 224 is deformed by bending in the direction of the arrangement of the multiple battery cells BC. In the second busbar weld 223, the edge on the terminal weld 221 side is superimposed on the notch 211a. The second spring portion 225 is formed by extending upward from the edge of the second busbar weld 223 toward the side opposite to the first electrode terminal BCa, and then folding back toward the first electrode terminal BCa at the end of the extended portion (Figure 14). This second spring portion 225 is deformed by bending in a direction perpendicular to the arrangement direction of the multiple battery cells BC. The terminal weld portion 221 connects the end of the first spring portion 224 that is folded back toward the first electrode terminal BCa side with the end of the second spring portion 225 that is folded back toward the first electrode terminal BCa side (Figure 14). The terminal weld portion 221 shown here is formed in a disc shape parallel to the plane (welding surface) of the first electrode terminal BCa. The circuit conductor connection portion 226 is connected to the other side of the second busbar weld portion 223 and protrudes from the first busbar body 210 (Figure 14).

[0114] In this specific example 2, even if the position of the first electrode terminal BCa and the second electrode terminal BCa shifts within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC during use of the battery module BM, the busbar 201 can absorb the displacement of the electrode terminal BCa with the first spring portion 224 and the second spring portion 225, thereby allowing the busbar 201 to follow the displacement of the electrode terminal BCa within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC. Furthermore, in this specific example 2, even if the terminal pitch shifts within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC during use of the battery module BM, the busbar 201 can absorb the displacement of the terminal pitch with the first spring portion 224, thereby allowing the busbar 201 to follow the displacement of the cell pitch within the design tolerance range due to thermal expansion and contraction of one battery cell BC and the other battery cell BC.

[0115] Furthermore, in this specific example 2, the busbar 201 is formed by shaping the first busbar body 210 into a flat plate, and then attaching the second busbar body 220, which has a tolerance absorption structure (first spring portion 224 and second spring portion 225), to the first terminal connector 211, which has the central portion between the first terminal connector 211 and the second terminal connector 212 of the first busbar body 210 removed. As a result, this busbar 201 can connect the first electrode terminal BCa and the second electrode terminal BCa with the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, in this specific example 2, the busbar 201 is provided with a tolerance absorption structure (first spring portion 224 and second spring portion 225) at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation of the battery cell BC is highest. This suppresses heat generation in the first busbar body 210, and allows for miniaturization of the heat-resistant structure (i.e., the cross-sectional area of ​​the central part of the first busbar body 210). [Explanation of Symbols]

[0116] 1,2,3,4,5,6,7,101,201 Busba 10, 20, 30, 40, 50, 60, 70 Busbar body 11,21,31,41,51,61,71 First terminal connector 12,22,32,42,52,62,72 Second terminal connector 13, 23, 33, 35, 43, 53, 63, 73, 75 Through holes 14,24,34,36,44,54,64,74,76 Flexible part 14a, 24a, 34a, 36a, 44a, 54a, 64a, 74a, 76a Terminal Weld 14b, 24b, 34b, 36b, 44b, 54b, 64b, 74b, 76b First spring section (spring section) 110,210 First bus bar unit 111,211 First terminal connector 111a,211a Notch 112,212 Second terminal connector 120,220 Second bus bar unit 121,221 Terminal weld 122,222 First busbar weld 123,223 Second busbar weld 124,224 First spring section 125,225 Second spring section 126,226 Circuit conductor connection

Claims

1. The battery module is formed in a flat plate shape and comprises a busbar body that is positioned between adjacent battery cells in a battery module in which multiple battery cells are arranged. The busbar body is divided into a first terminal connector, which is to be welded to the first electrode terminal of one of the battery cells, and a second terminal connector, which is to be welded to the second electrode terminal of the other battery cell. At least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded, and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction. The flexible portion is formed in a cantilever shape, projecting from the outer edge of the through hole toward the center of the hole in a direction perpendicular to the arrangement direction of the plurality of battery cells, and is provided in pairs with their projection directions opposite to each other. The busbar is characterized in that the terminal welding portion is provided at the free end of the flexible portion.

2. A busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, The busbar body is divided into a first terminal connector, which is to be welded to the first electrode terminal of one of the battery cells, and a second terminal connector, which is to be welded to the second electrode terminal of the other battery cell. At least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded, and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction. The flexible portion is formed in a cantilever shape, projecting from the outer edge of the through hole toward the center of the hole in the direction of arrangement of the plurality of battery cells, and is provided in pairs with their projection directions opposite to each other. The busbar is characterized in that the terminal welding portion is provided at the free end of the flexible portion.

3. A busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, The busbar body is divided into a first terminal connector, which is to be welded to the first electrode terminal of one of the battery cells, and a second terminal connector, which is to be welded to the second electrode terminal of the other battery cell. At least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded, and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction. The first terminal connector has a first through hole as the through hole and a first flexible portion as the flexible portion, The second terminal connector has a second through-hole as the through-hole and a second flexible portion as the flexible portion, The first flexible portion is formed in a cantilever shape, projecting from the outer edge of the first through-hole toward the center of the hole in a direction perpendicular to the arrangement direction of the plurality of battery cells. The terminal welding portion of the first flexible portion is provided at the free end of the first flexible portion and welded to the first electrode terminal. The second flexible portion is formed in a cantilever shape that protrudes from the outer peripheral edge of the second through hole toward the center of the hole in the direction of arrangement. A busbar characterized in that the terminal welding portion of the second flexible portion is provided at the free end of the second flexible portion and welded to the second electrode terminal.

4. The bus bar according to claim 3, characterized in that the flexible portions are provided in pairs with their protruding directions facing opposite directions.

5. A busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, The busbar body is divided into a first terminal connector, which is to be welded to the first electrode terminal of one of the battery cells, and a second terminal connector, which is to be welded to the second electrode terminal of the other battery cell. At least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded, and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction. The aforementioned through hole is formed in a circular shape, The flexible portion is formed in a cantilever shape, protruding from the outer peripheral edge of the through hole toward the center of the hole, and multiple such flexible portions are provided at equal intervals around the circumference of the through hole. The busbar is characterized in that the terminal welding portion is provided at the free end of the flexible portion.

6. A busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, The busbar body is divided into a first terminal connector, which is to be welded to the first electrode terminal of one of the battery cells, and a second terminal connector, which is to be welded to the second electrode terminal of the other battery cell. At least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded, and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction. The flexible portion is formed in a cantilevered beam shape, with each portion projecting toward the center of the through-hole from two opposing locations on the outer edge of the through-hole in a direction perpendicular to the arrangement direction of the plurality of battery cells. The terminal welding portion is positioned in the center of the flexible portion and in the center of the through hole. The bus bar is characterized in that the spring portion is provided between the terminal weld and one fixed end, and between the terminal weld and the other fixed end.

7. A busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, The busbar body is divided into a first terminal connector, which is to be welded to the first electrode terminal of one of the battery cells, and a second terminal connector, which is to be welded to the second electrode terminal of the other battery cell. At least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded, and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction. The flexible portion is formed in a cantilevered beam shape, with each portion projecting toward the center of the through hole from two opposing locations on the outer edge of the through hole in the direction of arrangement of the multiple battery cells. The terminal welding portion is positioned in the center of the flexible portion and in the center of the through hole. The bus bar is characterized in that the spring portion is provided between the terminal weld and one fixed end, and between the terminal weld and the other fixed end.

8. A busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, The busbar body is divided into a first terminal connector, which is to be welded to the first electrode terminal of one of the battery cells, and a second terminal connector, which is to be welded to the second electrode terminal of the other battery cell. At least one of the first terminal connector and the second terminal connector has a through hole that exposes the electrode terminal to be welded, and a flexible portion that protrudes from the outer edge of the through hole toward the center of the hole and is flexible, The flexible portion comprises a terminal welding portion for welding to the electrode terminal to be welded, and a spring portion provided between the terminal welding portion and the fixed end on the outer peripheral edge side of the through hole, which is elastically deformable in its own protruding direction and in the opposite direction. The first terminal connector has a first through hole as the through hole and a first flexible portion as the flexible portion, The second terminal connector has a second through-hole as the through-hole and a second flexible portion as the flexible portion, The first flexible portion is formed in a cantilevered beam shape, with each portion projecting toward the center of the hole from two opposing locations on the outer edge of the first through-hole in a direction perpendicular to the arrangement direction of the plurality of battery cells. The terminal welding portion of the first flexible portion is located in the center of the first flexible portion and in the center of the first through hole, and is welded to the first electrode terminal. The spring portion of the first flexible portion is provided between the terminal weld portion and one fixed end and between the terminal weld portion and the other fixed end, respectively. The second flexible portion is formed in a cantilevered beam shape, with each portion projecting toward the center of the hole from two opposing locations on the outer edge of the second through hole in the direction of arrangement. The terminal welding portion of the second flexible portion is located in the center of the second flexible portion and in the center of the hole of the second through hole, and is welded to the second electrode terminal. A bus bar characterized in that the spring portion of the second flexible portion is provided between the terminal weld portion and one fixed end of the second flexible portion, and between the terminal weld portion and the other fixed end.

9. A first busbar body formed in a flat plate shape and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, A second busbar body is physically and electrically connected to the first busbar body, Equipped with, The first busbar body is divided into a first terminal connector having a notch or through hole that exposes the first electrode terminal of one of the battery cells, and the first electrode terminal being electrically connected via the second busbar body, and a second terminal connector that is to be welded to the second electrode terminal of the other battery cell. The second busbar body is positioned in the notch or through-hole of the first terminal connector and is characterized by having a terminal welding portion for welding to the first electrode terminal, a first busbar welding portion for welding to the first terminal connector, a second busbar welding portion for welding to the first terminal connector, a first spring portion provided between the terminal welding portion and the first busbar welding portion and elastically deformable in the direction of alignment of the terminal welding portion and the first busbar welding portion and in the opposite direction, a second spring portion provided between the terminal welding portion and the second busbar welding portion and elastically deformable in the direction of alignment of the terminal welding portion and the second busbar welding portion and in the opposite direction, and a circuit conductor connection portion for physically and electrically connecting to a circuit conductor to be electrically connected to a battery monitoring unit.

10. The busbar according to claim 9, characterized in that the second busbar body is arranged in a line with the first busbar weld, the first spring, the terminal weld, the second spring, and the second busbar weld in that order, and is connected to the first busbar body with the direction of arrangement facing the direction of arrangement of the plurality of battery cells or a direction perpendicular to the direction of arrangement of the plurality of battery cells.

11. The busbar according to claim 9, wherein the second busbar body is arranged such that the first busbar weld portion, the first spring portion, and the terminal weld portion are arranged in that order in a first direction, and the terminal weld portion, the second spring portion, and the second busbar weld portion are arranged in that order in a second direction perpendicular to the first direction, and the first direction is oriented in the direction of arrangement of the plurality of battery cells, and the second direction is oriented perpendicular to the direction of arrangement of the plurality of battery cells, and is connected to the first busbar body.

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