Bus bar

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 technology]

[0002] In a conventional battery module in which multiple battery cells are arranged, a single bus bar physically and electrically connects the electrode terminals of adjacent battery cells in the arrangement direction. The bus bar includes a first terminal connector that physically and electrically connects one of the electrode terminals and a second terminal connector that physically and electrically connects the other electrode terminal. Meanwhile, in a battery module, the bus bar is provided with a tolerance absorbing structure to absorb deviations within the design tolerance of the inter-terminal pitch due to thermal expansion and contraction of the battery cells and deviations within the design tolerance of the inter-terminal pitch due to variations in the assembly tolerance of the multiple battery cells. The bus bar is provided with a tolerance absorbing structure using a cutout or other hollow portion between the first terminal connector and the second terminal connector (i.e., in the center portion in the arrangement direction of the multiple battery cells) to absorb deviations in the inter-terminal pitch. For example, this type of bus bar is disclosed in Patent Document 1 listed below. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-243689 Summary of the Invention [Problem to be solved by the invention]

[0004] In a bus bar, the central portion between the first terminal connector and the second terminal connector, where the tolerance absorption structure is provided, is the most susceptible to heat generation, so it is necessary to increase the heat resistance of the central portion by, for example, increasing the cross-sectional area of the central portion.However, in conventional bus bars, the tolerance absorption structure and the heat-resistant structure are provided in the same location (the central portion), leaving room for improvement in the placement of the tolerance absorption structure.

[0005] Therefore, an object of the present invention is to provide a bus bar in which a tolerance absorbing structure is disposed in a suitable location. [Means for solving the problem]

[0006] The present invention comprises a busbar main body formed in a flat plate and arranged between adjacent battery cells in a battery module in which a plurality of battery cells are arranged, the busbar main body being divided into a first terminal connector to be welded to a first electrode terminal of one of the battery cells and a second terminal connector to be welded to a second electrode terminal of the other battery cell, at least one of the first terminal connector and the second terminal connector having a through hole exposing the electrode terminal to be welded and a flexible portion that protrudes from the outer periphery of the through hole toward the center of the hole and has flexibility, the flexible portion having a terminal weld portion to be welded to the electrode terminal to be welded, and a spring portion that is provided between the terminal weld portion and a fixed end on the outer periphery side of the through hole and is elastically deformable in the protruding direction and the opposite direction.

[0007] The present invention also provides a battery module including a first busbar body formed in a flat plate shape and arranged between adjacent battery cells in an array of a plurality of battery cells, and a second busbar body physically and electrically connected to the first busbar body, wherein the first busbar body has a cutout portion or a through-hole portion that exposes a 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 a second electrode terminal of the other battery cell is to be welded, and the second busbar body has a cutout portion or a through-hole portion that exposes a first electrode terminal of the one of the battery cells. the through hole portion is disposed in the through hole portion and includes a terminal welding portion welded to the first electrode terminal, a first bus bar welding portion welded to the first terminal connector, a second bus bar welding portion welded to the first terminal connector, a first spring portion provided between the terminal welding portion and the first bus bar welding portion and elastically deformable in the arrangement direction of the terminal welding portion and the first bus bar welding portion and the opposite direction, a second spring portion provided between the terminal welding portion and the second bus bar welding portion and elastically deformable in the arrangement direction of the terminal welding portion and the second bus bar welding portion and the opposite direction, and a circuit conductor connection portion for physically and electrically connecting to a circuit conductor that is electrically connected to a battery monitoring unit. [Effects of the Invention]

[0008] The bus bar according to the present invention includes a bus bar body having such a structure or includes first and second bus bar bodies having such a structure, allowing the spring portions to function as a tolerance-absorbing structure. For example, even if the spacing in the arrangement direction (so-called inter-terminal pitch) between the electrode terminals of two adjacent battery cells deviates within the design tolerance range, the spring portions absorb the deviation in the inter-terminal pitch, allowing the bus bar to be welded to the respective electrode terminals. Furthermore, even if the inter-terminal pitch or the position of the electrode terminals deviates within the design tolerance range due to thermal expansion or contraction of the battery cells during use of the battery module, the spring portions absorb the deviation in the inter-terminal pitch or the positional deviation of the electrode terminals, allowing the bus bar to accommodate deviations in the inter-cell pitch within the design tolerance range due to thermal expansion or contraction of the battery cells, or deviations in the position of the electrode terminals within the design tolerance range due to thermal expansion or contraction of the battery cells. The bus bar according to the present invention has a spring portion (tolerance absorbing structure) located away from the center portion between the first terminal connector and the second terminal connector, allowing the center portion to have a heat-resistant structure without being restricted by the tolerance absorbing structure. Furthermore, the bus bar according to the present invention has a spring portion (tolerance absorbing structure) located at the welded portion with the electrode terminal, where the temperature reduction effect due to heat dissipation from the battery cell is greatest, thereby suppressing heat generation itself and enabling the heat-resistant structure (i.e., the cross-sectional area of the center portion) to be made smaller. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a bus bar according to a first specific example of an embodiment. [Figure 2] FIG. 2 is an explanatory diagram of a bus bar according to a first specific example of the embodiment. [Figure 3] FIG. 3 is an explanatory diagram showing an example of the ability of a flexible section to follow when an electrode terminal is misaligned in a direction perpendicular to the arrangement direction of a plurality of battery cells. [Figure 4] FIG. 4 is an explanatory diagram showing an example of the followability of the flexible portion when the electrode terminal is displaced in a direction perpendicular to the plane of the first terminal connector (the plane of the first electrode terminal). [Figure 5] FIG. 5 is a perspective view showing a bus bar according to a second specific example of the embodiment. [Figure 6] FIG. 6 is a perspective view showing a bus bar according to a third specific example of the embodiment. [Figure 7] FIG. 7 is a perspective view showing a bus bar according to a fourth specific example of the embodiment. [Figure 8] FIG. 8 is a perspective view showing a bus bar according to a fifth specific example of the embodiment. [Figure 9] FIG. 9 is a perspective view showing a bus bar according to a sixth specific example of the embodiment. [Figure 10] FIG. 10 is a perspective view showing a bus bar according to a seventh specific example of 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 a bus bar according to a first specific example of the modified embodiment. [Figure 13] FIG. 13 is an explanatory diagram illustrating a clamping portion of a first bus bar main body of a specific example 1 in a modified embodiment. [Figure 14] FIG. 14 is a perspective view showing a bus bar according to a second specific example of the modified embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the bus bar according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to these embodiments.

[0011] [Embodiment] One embodiment of a bus bar according to the present invention will be described with reference to FIGS.

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

[0013] In a battery module BM (FIG. 11) in which a plurality of battery cells BC are arranged (e.g., arranged in a row), the bus bar of this embodiment physically and electrically connects the electrode terminals BCa of one battery cell BC and the electrode terminals BCa of the other battery cell BC that are adjacent in the arrangement direction, thereby electrically connecting the electrode terminals BCa to each other. The bus bar is also electrically connected to a battery monitoring unit (not shown) via circuit conductors (not shown), allowing the battery monitoring unit to monitor the battery status (voltage, current, temperature, etc.) of the battery cells BC. Circuit conductors include, for example, electric wires and wiring patterns on flexible printed circuit boards (FPCs).

[0014] Each battery cell BC includes a cell body BCb and positive and negative electrode terminals BCa (FIG. 11). The battery cell BC shown here has a cell body BCb formed in a rectangular shape with six outer wall surfaces, with positive and negative flat electrode terminals BCa provided on one of the six outer wall surfaces. In the battery module BM, adjacent cell bodies BCb in the arrangement direction are arranged with their respective outer wall surfaces facing each other. In this battery module BM, one electrode terminal BCa of each battery cell BC is aligned along the arrangement direction, and the other electrode terminal BCa of each battery cell BC is aligned along the arrangement direction. Alternatively, the battery cell BC may have a positive flat electrode terminal BCa and a negative flat electrode terminal BCa provided on different outer wall surfaces of the six outer wall surfaces.

[0015] The bus bar of this embodiment includes a bus bar main body formed in a flat plate shape. This bus bar main body is disposed between adjacent battery cells BC.

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

[0017] The bus bar of this embodiment has a bus bar body with such a shape, allowing the spring portion of the flexible portion to function as a tolerance-absorbing structure. For example, even if the spacing (so-called inter-terminal pitch) between the electrode terminals BCa of two adjacent battery cells BC in the arrangement direction deviates within the design tolerance, the spring portion of the bus bar can absorb the deviation in the inter-terminal pitch, allowing the bus bar to be welded to each electrode terminal BCa. Furthermore, even if the inter-terminal pitch deviates within the design tolerance due to thermal expansion or contraction of the battery cells BC during use of the battery module BM, or the position of the electrode terminals BCa deviates within the design tolerance due to thermal expansion or contraction of the battery cells BC, the spring portion can absorb the deviation in the inter-terminal pitch or the positional deviation of the electrode terminals BCa.

[0018] The bus bar of this embodiment has a spring portion (tolerance absorbing structure) located away from the center portion between the first terminal connector and the second terminal connector, allowing the center portion to have a heat-resistant structure without being restricted by the tolerance absorbing structure. Furthermore, the bus bar of this embodiment has a spring portion (tolerance absorbing structure) located at the welded portion with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation from the battery cell BC is greatest, thereby suppressing heat generation and enabling the heat-resistant structure (i.e., the cross-sectional area of the center portion) to be made smaller.

[0019] A specific example of the bus bar of this embodiment will be described below.

[0020] [Example 1] Reference numeral 1 in Fig. 1 indicates a busbar of specific example 1 of this embodiment. This busbar 1 includes a busbar body 10 formed into a rectangular flat plate from a conductive material such as metal (Fig. 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 (Fig. 1).

[0021] In this busbar body 10, a rectangular, flat-plate 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 the rectangular, flat-plate 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 manner as in the conventional busbar body. Thus, the through-hole 13 is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The through-hole 13 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. 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 from the through hole 13, and a spring portion 14b that is provided between the terminal welding portion 14a and the fixed end on the outer peripheral edge side of the through hole 13 and is elastically deformable in its own protruding direction and in the opposite direction (Figures 1 and 2).

[0023] The flexible portion 14 is formed in a cantilever shape that protrudes from the outer periphery 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 (FIGS. 1 and 2). The terminal welding portion 14a is provided at the free end of the flexible portion 14 (FIGS. 1 and 2).

[0024] The flexible portion 14 is formed by bending a rectangular, flat 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 periphery 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 (FIGS. 1 and 2). The second spring portion 14c flexes 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- or U-shape with the protruding end of the second spring portion 14c rising on the side opposite the first electrode terminal BCa and then folded back toward the first electrode terminal BCa (FIGS. 1 and 2). The first spring portion 14b flexes in a direction perpendicular to the arrangement direction of the multiple battery cells BC. Furthermore, the terminal welding portion 14a is folded back toward the first electrode terminal BCa at the end of the 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 (FIGS. 1 and 2). The terminal welding portion 14a shown here is formed in a rectangular plate shape 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 (FIGS. 1 and 2). The pair of flexible portions 14 are aligned in a direction perpendicular to the arrangement direction of the multiple battery cells BC.

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

[0027] In addition, in the busbar 1 of this specific example 1, the busbar body 10 is formed into a flat plate, and the first spring portion 14b and the second spring portion 14c, which serve as the tolerance absorbing structure, are provided on the first terminal connector 11, which is located outside the center portion of the busbar body 10. This allows the busbar 1 to connect the first electrode terminal BCa and the second electrode terminal BCa using the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, in the busbar 1 of this specific example 1, the tolerance absorbing structure (the first spring portion 14b and the second spring portion 14c) is provided at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation from the battery cell BC is greatest. This suppresses heat generation itself, allowing the heat-resistant structure (i.e., the cross-sectional area of the center portion of the busbar body 10) to be made smaller.

[0028] In addition, in the bus bar 1 of this specific example 1, the second spring portion 14c may not be provided, and in this case, the function of absorbing the positional deviation of the electrode terminal BCa caused by the second spring portion 14c may be performed by the first spring portion 14b.

[0029] [Example 2] Reference numeral 2 in Fig. 5 indicates a busbar of specific example 2 of this embodiment. This busbar 2 includes a busbar body 20 formed into a rectangular flat plate from a conductive material such as metal (Fig. 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 (Fig. 5).

[0030] In this busbar main body 20, a through hole 23 and a flexible portion 24 are provided in a rectangular, flat-plate-shaped first terminal connector 21. The flexible portion 24 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and the rectangular, flat-plate-shaped 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 manner as in the conventional busbar main body 20. Thus, the through hole 23 is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The through hole 23 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. The through hole 23 shown here is formed in a circular shape. Note that 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 from the through hole 23, and a spring portion 24b that is provided between the terminal welding portion 24a and the fixed end on the outer peripheral edge side of the through hole 23 and is elastically deformable in its own protruding direction and in the opposite direction (Figure 5).

[0032] The flexible portion 24 is formed in a cantilever shape that protrudes from the outer periphery of the through-hole 23 toward the center of the hole in the arrangement direction of the multiple battery cells BC (FIG. 5). The terminal welding portion 24a is provided at the free end of the flexible portion 24 (FIG. 5).

[0033] The flexible portion 24 is formed in the same shape as the flexible portion 14 of Example 1. Therefore, the flexible portion 24 has a flat spring portion (hereinafter referred to as the "second spring portion") 24c that protrudes from the outer periphery of the through-hole 23 toward the center of the hole in the arrangement direction of the multiple battery cells BC (FIG. 5). The second spring portion 24c flexes in a direction perpendicular to the plane of the first terminal connector 21 (the plane of the first electrode terminal BCa). The spring portion (hereinafter referred to as the "first spring portion") 24b shown here is formed in a V- or U-shape with the protruding end of the second spring portion 24c rising on the side opposite to the first electrode terminal BCa and then folded back toward the first electrode terminal BCa (FIG. 5). The first spring portion 24b flexes in the arrangement direction of the multiple battery cells BC. Furthermore, the terminal welding portion 24a is folded back toward the first electrode terminal BCa at the end of the first spring portion 24b, and protrudes toward the center of the through-hole 23 in the arrangement direction of the multiple battery cells BC (FIG. 5). The terminal welding portion 24a shown here is formed in a rectangular plate shape that is 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 (FIG. 5). The pair of flexible portions 24 are aligned in the arrangement direction of the multiple battery cells BC.

[0035] In the bus bar 2 of specific example 2, even if the positions of the first electrode terminals BCa and the second electrode terminals BCa shift within the design tolerance range due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the first spring portions 24b and the second spring portions 24c absorb the positional shift of the electrode terminals BCa, thereby allowing the bus bar 2 to follow the positional shift of the electrode terminals BCa within the design tolerance range due to thermal expansion or thermal contraction of the one battery cell BC or the other battery cell BC. Furthermore, even if the inter-terminal pitch shifts within the design tolerance range due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 2 of specific example 2 can follow the inter-cell pitch shift within the design tolerance range due to thermal expansion or thermal contraction of the one battery cell BC or the other battery cell BC by absorbing the misalignment of the terminal pitch with the first spring portions 24b.

[0036] In addition, in the busbar 2 of this specific example 2, the busbar body 20 is formed into a flat plate, and the first spring portion 24b and the second spring portion 24c, which serve as the tolerance absorbing structure, are provided on the first terminal connector 21, which is located outside the center portion of the busbar body 20. This allows the busbar 2 to connect the first electrode terminal BCa and the second electrode terminal BCa using the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, in the busbar 2 of this specific example 2, the tolerance absorbing structure (the first spring portion 24b and the second spring portion 24c) is provided at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation from the battery cell BC is greatest. This suppresses heat generation itself, and allows the heat-resistant structure (i.e., the cross-sectional area of the center portion of the busbar body 20) to be made smaller.

[0037] In addition, the bus bar 2 of this specific example 2 does not need to be provided with the second spring portion 24c. In this case, the first spring portion 24b may be responsible for absorbing the positional deviation of the electrode terminal BCa caused by the second spring portion 24c.

[0038] [Example 3] Reference numeral 3 in Fig. 6 indicates a busbar of specific example 3 of this embodiment. This busbar 3 includes a busbar body 30 formed into a rectangular flat plate from a conductive material such as metal (Fig. 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 (Fig. 6).

[0039] In this busbar main body 30, 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 are provided in a rectangular, flat-plate-shaped first terminal connector 31, 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 through hole (hereinafter referred to as the "second through hole") 35 and a flexible portion (hereinafter referred to as the "second flexible portion") 36 are provided in a rectangular, flat-plate-shaped second terminal connector 32, 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 ( FIG. 6 ).

[0040] The first through hole 33 is placed over the first electrode terminal BCa to expose 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 to expose the entire flat surface (welding surface) of the first electrode terminal BCa. The second through hole 35 is placed over the second electrode terminal BCa to expose 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 to expose the entire flat surface (welding surface) of the second electrode terminal BCa. The first through hole 33 and 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 that is provided between this terminal welding portion 34a and the fixed end on the outer peripheral edge side of the first through hole 33 and 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 that protrudes from the outer periphery 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 (FIG. 6). The terminal welding portion 34a is provided at the free end of the first flexible portion 34 and is welded to the first electrode terminal BCa (FIG. 6).

[0043] The first flexible portion 34 is formed in the same shape as the flexible portion 14 of Example 1 and is disposed in the same location as the flexible portion 14 of Example 1. Therefore, the first flexible portion 34 has a flat spring portion (hereinafter referred to as the "second spring portion") 34c that protrudes from the outer periphery of the first through-hole 33 toward the center of the hole in a direction perpendicular to the arrangement direction of the plurality of battery cells BC (FIG. 6). The second spring portion 34c flexes and deforms in a direction perpendicular to the plane of the first terminal connector 31 (the plane of the first electrode terminal BCa). The spring portion (hereinafter referred to as the "first spring portion") 34b shown here is formed in a V- or U-shape with the protruding end of the second spring portion 34c rising on the side opposite to the first electrode terminal BCa and then folded back toward the first electrode terminal BCa (FIG. 6). The first spring portion 34b is flexibly deformed in a direction perpendicular to the arrangement direction of the multiple battery cells BC. Furthermore, the terminal welding portion 34a is folded back toward the first electrode terminal BCa, and protrudes toward the center of the first through-hole 33 in a direction perpendicular to the arrangement direction of the multiple battery cells BC (FIG. 6). The terminal welding portion 34a shown here is formed in a rectangular plate shape that is parallel to the plane (welding surface) of the first electrode terminal BCa.

[0044] The first terminal connector 31 has a pair of first flexible portions 34 that protrude in opposite directions (FIG. 6). The pair of first flexible portions 34 are aligned 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 that is provided between this terminal welding portion 36a and the fixed end on the outer peripheral edge side of the second through hole 35 and is elastically deformable in its own protruding direction and in the opposite direction (Figure 6).

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

[0047] The second flexible portion 36 has a shape similar to that of the flexible portion 24 of Example 2 and is located in a similar position to that of the flexible portion 24 of Example 2. Therefore, the second flexible portion 36 has a flat spring portion (hereinafter referred to as the "second spring portion") 36c that protrudes from the outer periphery of the second through-hole 35 toward the center of the hole in the arrangement direction of the plurality of battery cells BC (FIG. 6). The second spring portion 36c flexes in a direction perpendicular to the plane of the second terminal connector 32 (the plane of the second electrode terminal BCa). The spring portion (hereinafter referred to as the "first spring portion") 36b shown here is formed in a V- or U-shape with the protruding end of the second spring portion 36c rising on the side opposite to the second electrode terminal BCa and then folded back toward the second electrode terminal BCa (FIG. 6). The first spring portion 36b flexes in the arrangement direction of the plurality of battery cells BC. Furthermore, the terminal welding portion 36a is folded back toward the second electrode terminal BCa at the end of the first spring portion 36b, and protrudes toward the center of the second through-hole 35 in the arrangement direction of the multiple battery cells BC (FIG. 6). The terminal welding portion 36a shown here is formed in a rectangular plate shape that is parallel to the plane (welding surface) of the second electrode terminal BCa.

[0048] The second terminal connector 32 has a pair of second flexible portions 36 that protrude in opposite directions (FIG. 6). The pair of second flexible portions 36 are aligned in the arrangement direction of the multiple battery cells BC.

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

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

[0051] In addition, in the busbar 3 of this specific example 3, the busbar body 30 is formed into a flat plate, and the first spring portion 34b and the second spring portion 34c of the first flexible portion 34, which constitutes the tolerance absorbing structure, are provided on the first terminal connector 31, which is located away from 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 also constitutes the tolerance absorbing structure, are provided on the second terminal connector 32, which is located away from the central portion of the busbar body 30. Therefore, in this busbar 3, the first electrode terminal BCa and the second electrode terminal BCa can be connected via the shortest possible current path, thereby minimizing the resistance value and heat generation. Furthermore, the busbar 3 of this specific example 3 has a tolerance absorption structure (the first spring portion 34b and the second spring portion 34c of the first flexible portion 34, and the first spring portion 36b and the second spring portion 36c of the second flexible portion 36) at the welding point with the electrode terminal BCa, which has the greatest temperature reduction effect due to heat dissipation from the battery cell BC, so that heat generation by the busbar itself can be suppressed and the heat-resistant structure (i.e., the cross-sectional area of the central part of the busbar body 30) can be made smaller.

[0052] In addition, in the busbar 3 of this specific example 3, the second spring portions 34c, 36c may not be provided, and in this case, the function of absorbing the positional deviation of the electrode terminal BCa caused by the second spring portions 34c, 36c may be performed by the first spring portions 34b, 36b.

[0053] [Example 4] Reference numeral 4 in Fig. 7 indicates a busbar according to a fourth specific example of this embodiment. This busbar 4 includes a busbar body 40 formed into a rectangular flat plate from a conductive material such as metal (Fig. 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 (Fig. 7).

[0054] In this busbar main body 40, a rectangular, flat-plate 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-plate 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 a conventional manner. Thus, the through-hole 43 is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The through-hole 43 is formed in a circular shape larger than the first electrode terminal BCa, exposing the entire flat surface (welding 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 from the through hole 43, and a spring portion 44b that is provided between the terminal welding portion 44a and the fixed end on the outer peripheral edge side of the through hole 43 and is elastically deformable in its own protruding direction and in the opposite direction (Figure 7).

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

[0057] The flexible portion 44 is formed in the same shape as the flexible portion 14 of Example 1 and the flexible portion 24 of Example 2. Therefore, the flexible portion 44 has a flat spring portion (hereinafter referred to as the "second spring portion") 44c that protrudes from the outer periphery of the through-hole 43 toward the center of the hole (FIG. 7). The second spring portion 44c flexes in a direction perpendicular to the plane of the first terminal connector 41 (the plane of the first electrode terminal BCa). The spring portion (hereinafter referred to as the "first spring portion") 44b shown here is formed in a V- or U-shape with the protruding end of the second spring portion 44c rising on the side opposite to the first electrode terminal BCa and then folded back toward the first electrode terminal BCa (FIG. 7). The first spring portion 44b flexes in the direction of protrusion from the outer periphery of the through-hole 43 in the flexible portion 44 and in the opposite direction. The terminal welding portion 44a is folded back toward the first electrode terminal BCa at the first spring portion 44b, and protrudes toward the center of the through-hole 43 (FIG. 7). The terminal welding portion 44a shown here is formed in a rectangular plate shape parallel to the plane (welding surface) of the first electrode terminal BCa.

[0058] Even if the positions of the first electrode terminals BCa and the second electrode terminals BCa shift within the design tolerance range due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 4 of this specific example 4 can accommodate the positional shift of the electrode terminals BCa within the design tolerance range due to thermal expansion or thermal contraction of the one battery cell BC or the other battery cell BC by absorbing the positional shift of the electrode terminals BCa with the first spring portions 44b and second spring portions 44c of the respective flexible portions 44. Furthermore, even if the inter-terminal pitch shifts within the design tolerance range due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 4 of this specific example 4 can accommodate the inter-cell pitch shifts within the design tolerance range due to thermal expansion or thermal contraction of the one battery cell BC or the other battery cell BC by absorbing the inter-terminal pitch shift with the first spring portions 24b of the respective flexible portions 44.

[0059] In addition, in the busbar 4 of this specific example 4, the busbar body 40 is formed into a flat plate, and the first spring portion 44b and the second spring portion 44c of each flexible portion 44, which form the tolerance absorbing structure, are provided on the first terminal connector 41, which is located outside the central portion of the busbar body 40. This allows the busbar 4 to connect the first electrode terminal BCa and the second electrode terminal BCa via the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, the busbar 4 of this specific example 4 has the tolerance absorbing structure (the first spring portion 44b and the second spring portion 44c of each flexible portion 44) provided at the welded portion with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation from the battery cell BC is greatest. This reduces heat generation itself, allowing the heat-resistant structure (i.e., the cross-sectional area of the central portion of the busbar body 40) to be made smaller.

[0060] In addition, the bus bar 4 of this specific example 4 does not need to be provided with the second spring portion 44c. In this case, the function of absorbing the positional deviation of the electrode terminal BCa caused by the second spring portion 44c may be performed by the first spring portion 44b.

[0061] [Example 5] Reference numeral 5 in Fig. 8 indicates a busbar of specific example 5 of this embodiment. This busbar 5 includes a busbar body 50 formed into a rectangular flat plate from a conductive material such as metal (Fig. 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 (Fig. 8).

[0062] In this busbar main body 50, a through hole 53 and a flexible portion 54 are provided in a rectangular, flat-plate-shaped first terminal connector 51. The flexible portion 54 is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like, and the rectangular, flat-plate-shaped 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 manner as in the conventional busbar main body 50. Thus, the through hole 53 is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The through hole 53 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. The through hole 53 shown here is formed in a circular shape. Note that a through hole for welding may be provided in the second terminal connector 52.

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

[0064] The flexible section 54 is formed in the shape of a doubly supported beam that protrudes from two opposing locations on the outer periphery of the through-hole 53 toward the center of the hole in a direction perpendicular to the arrangement direction of the multiple battery cells BC ( FIG. 8 ). The terminal weld section 54a is located at the center of the flexible section 54 and at the center of the through-hole 53 ( FIG. 8 ). The spring sections 54b are provided between the terminal weld section 54a and one fixed end, and between the terminal weld section 54a and the other fixed end, respectively ( FIG. 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 opposing locations on the outer periphery of the through-hole 53 in a direction perpendicular to the arrangement direction of the multiple battery cells BC (FIG. 8). Each second spring portion 54c flexes in a direction perpendicular to the plane of the first terminal connector 51 (the plane of the first electrode terminals BCa). The spring portion (hereinafter referred to as "first spring portion") 54b shown here is formed in a V- or U-shape with the protruding end of the second spring portion 54c rising on the side opposite the first electrode terminals BCa and then folded back toward the first electrode terminals BCa (FIG. 8). Each first spring portion 54b flexes in a direction perpendicular to the arrangement direction of the multiple battery cells BC. The terminal welding portion 54a connects the ends of the first spring portions 54b that are folded back toward the first electrode terminal BCa (FIG. 8). The terminal welding portion 54a shown here is formed in a disk shape that is 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 terminals BCa and the second electrode terminals BCa shift within the design tolerance range due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 5 can accommodate the positional shift of the electrode terminals BCa within the design tolerance range due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC by absorbing the positional shift of the electrode terminals BCa with the pair of first spring portions 54b and the pair of second spring portions 54c.

[0067] In addition, in the busbar 5 of this specific example 5, the busbar body 50 is formed into a flat plate, and the first spring portion 54b and the second spring portion 54c, which serve as the tolerance absorbing structure, are provided on the first terminal connector 51, which is located outside the center portion of the busbar body 50. As a result, the busbar 5 can connect the first electrode terminal BCa and the second electrode terminal BCa using the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, the busbar 5 of this specific example 5 has the tolerance absorbing structure (the first spring portion 54b and the second spring portion 54c) provided at the welding location with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation from the battery cell BC is greatest. This reduces heat generation in the busbar 5 itself, allowing the heat-resistant structure (i.e., the cross-sectional area of the center portion of the busbar body 50) to be made smaller.

[0068] In addition, the bus bar 5 of this specific example 5 does not need to be provided with the second spring portion 54c. In this case, the function of absorbing the positional deviation of the electrode terminal BCa caused by the second spring portion 54c may be performed by the first spring portion 54b.

[0069] [Example 6] Reference numeral 6 in Fig. 9 indicates a busbar according to specific example 6 of this embodiment. This busbar 6 includes a busbar body 60 formed into a rectangular flat plate from a conductive material such as metal (Fig. 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 (Fig. 9).

[0070] In this busbar main body 60, a rectangular, flat-plate 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 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 manner as in the conventional busbar main body 60. Thus, the through-hole 63 is superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The through-hole 63 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. The through-hole 63 shown here is formed in a circular shape. Note that 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 from the through hole 63, and a spring portion 64b that is provided between the terminal welding portion 64a and the fixed end on the outer peripheral edge side of the through hole 63 and is elastically deformable in its own protruding direction and in the opposite direction (Figure 9).

[0072] The flexible section 64 is formed in the shape of a double-supported beam that protrudes from two opposing locations on the outer periphery of the through-hole 63 in the arrangement direction of the multiple battery cells BC toward the center of the hole (FIG. 9). The terminal welding section 64a is located at the center of the flexible section 64 and at the center of the through-hole 63 (FIG. 9). The spring section 64b is provided between the terminal welding section 64a and one fixed end, and between the terminal welding section 64a and the other fixed end, respectively (FIG. 9).

[0073] The flexible portion 64 is formed in the same shape as the flexible portion 54 of Example 5. Therefore, the 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 opposing locations on the outer periphery of the through-hole 63 in the arrangement direction of the multiple battery cells BC (FIG. 9). Each second spring portion 64c flexes in a direction perpendicular to the plane of the first terminal connector 61 (the plane of the first electrode terminals BCa). The spring portion (hereinafter referred to as "first spring portion") 64b shown here is formed in a V- or U-shape with the protruding end of the second spring portion 64c rising on the side opposite the first electrode terminals BCa and then folded back toward the first electrode terminals BCa (FIG. 9). Each first spring portion 64b flexes in the arrangement direction of the multiple battery cells BC. The terminal welding portion 64a connects the ends of the first spring portions 64b that are folded back toward the first electrode terminal BCa (FIG. 9). The terminal welding portion 64a shown here is formed in a disk shape that is parallel to the plane (welding surface) of the first electrode terminal BCa.

[0074] In the bus bar 6 of specific example 6, even if the positions of the first electrode terminals BCa and the second electrode terminals BCa shift within the range of the design tolerance due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the pair of first spring portions 64b and the pair of second spring portions 64c absorb the positional shift of the electrode terminals BCa, thereby allowing the bus bar 6 to follow the positional shift of the electrode terminals BCa within the range of the design tolerance due to thermal expansion or thermal contraction of the one battery cell BC or the other battery cell BC. Furthermore, even if the inter-terminal pitch shifts within the range of the design tolerance due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the pair of first spring portions 64b absorb the misalignment of the inter-terminal pitch, thereby allowing the bus bar 6 of specific example 6 to follow the misalignment of the inter-cell pitch within the range of the design tolerance due to thermal expansion or thermal contraction of the one battery cell BC or the other battery cell BC.

[0075] In addition, in the busbar 6 of Example 6, the busbar body 60 is formed into a flat plate, and the first spring portion 64b and the second spring portion 64c, which serve as the tolerance absorbing structure, are provided on the first terminal connector 61, which is located outside the central portion of the busbar body 60. This allows the busbar 6 to connect the first electrode terminal BCa and the second electrode terminal BCa via the shortest possible current path, thereby minimizing resistance and heat generation. Furthermore, in the busbar 6 of Example 6, the tolerance absorbing structure (the first spring portion 64b and the second spring portion 64c) is provided at the welding point with the electrode terminal BCa, where the temperature reduction effect due to heat dissipation from the battery cell BC is greatest. This suppresses heat generation itself, and allows the heat-resistant structure (i.e., the cross-sectional area of the central portion of the busbar body 60) to be made smaller.

[0076] In the bus bar 6 of this specific example 6, the second spring portion 64c may not be provided, and in this case, the function of absorbing the positional deviation of the electrode terminal BCa caused by the second spring portion 64c may be performed by the first spring portion 64b.

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

[0078] In this busbar main body 30, 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 are provided in a rectangular, flat-plate-shaped first terminal connector 71, 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 through hole (hereinafter referred to as the "second through hole") 75 and a flexible portion (hereinafter referred to as the "second flexible portion") 76 are provided in a rectangular, flat-plate-shaped second terminal connector 72, 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 ( FIG. 10 ).

[0079] The first through hole 73 is placed over the first electrode terminal BCa to expose 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 to expose the entire flat surface (welding surface) of the first electrode terminal BCa. The second through hole 75 is placed over the second electrode terminal BCa to expose 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 to expose the entire flat surface (welding surface) of the second electrode terminal BCa. The first through hole 73 and 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 that is provided between this terminal welding portion 74a and the fixed end on the outer peripheral edge side of the first through hole 73 and is elastically deformable in its own protruding direction and the opposite direction (Figure 10).

[0081] The first flexible portion 74 is formed in the shape of a doubly supported beam that protrudes from two opposing locations on the outer periphery of the first through-hole 73 toward the center of the hole in a direction perpendicular to the arrangement direction of the multiple battery cells BC ( FIG. 10 ). The terminal welding portion 74a is disposed at the center of the first flexible portion 74 and at the center of the first through-hole 73, and is welded to the first electrode terminal BCa ( FIG. 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, respectively ( FIG. 10 ).

[0082] The first flexible portion 74 is formed in the same shape as the flexible portion 54 of Example 5 and is disposed in the same location as the flexible portion 54 of Example 5. Therefore, the first flexible portion 74 has flat spring portions (hereinafter referred to as "second spring portions") 74c that protrude toward the center of the first through-hole 73 from two opposing locations on the outer periphery of the first through-hole 73 in a direction perpendicular to the arrangement direction of the plurality of battery cells BC ( FIG. 10 ). Each second spring portion 74c flexes and deforms 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- or U-shape with the protruding end of the second spring portion 74c rising on the side opposite the first electrode terminal BCa and then folded back toward the first electrode terminal BCa ( FIG. 10 ). Each of the first spring portions 74b is flexibly deformed in a direction perpendicular to the arrangement direction of the multiple battery cells BC. The terminal welding portion 74a connects the ends of each of the first spring portions 74b that are folded back toward the first electrode terminal BCa (FIG. 10). The terminal welding portion 74a shown here is formed in a disk shape that is 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 that is provided between this terminal welding portion 76a and the fixed end on the outer peripheral edge side of the second through hole 75 and is elastically deformable in its own protruding direction and the opposite direction (Figure 10).

[0084] The second flexible portion 76 is formed in the shape of a doubly supported beam that protrudes from two opposing locations on the outer periphery of the second through-hole 75 in the arrangement direction of the multiple battery cells BC toward the center of the hole (FIG. 10). The terminal welding portion 76a is disposed at the center of the second flexible portion 76 and at the center of the second through-hole 75, and is welded to the second electrode terminal BCa (FIG. 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, respectively (FIG. 10).

[0085] The second flexible portion 76 has a shape similar to that of the flexible portion 64 of Example 6 and is disposed in a location similar to that of the flexible portion 64 of Example 6. Therefore, the second flexible portion 76 has flat spring portions (hereinafter referred to as "second spring portions") 76c that protrude toward the center of the second through-hole 75 from two opposing locations on the outer periphery of the second through-hole 75 in the arrangement direction of the battery cells BC ( FIG. 10 ). Each second spring portion 76c flexes and deforms in a direction perpendicular to the plane of the second terminal connector 72 (the plane of the second electrode terminal BCa). The spring portion (hereinafter referred to as "first spring portion") 76b shown here is formed in a V- or U-shape with the protruding end of the second spring portion 76c rising toward the side opposite the second electrode terminal BCa and then folded back toward the second electrode terminal BCa ( FIG. 10 ). Each of the first spring portions 76b is flexibly deformed in the arrangement direction of the multiple battery cells BC. The terminal welding portion 76a connects the ends of each of the first spring portions 76b that are folded back toward the second electrode terminal BCa (FIG. 10). The terminal welding portion 76a shown here is formed in a disk shape that is parallel to the plane (welding surface) of the second electrode terminal BCa.

[0086] Even if the position of the first electrode terminal BCa shifts within the range of the design tolerance due to thermal expansion or thermal contraction of one battery cell BC during use of the battery module BM, the bus bar 7 of this specific example 7 can accommodate the positional shift of the first electrode terminal BCa within the range of the design tolerance due to thermal expansion or thermal contraction of one battery cell BC by absorbing the positional shift with the first spring portion 74b and the second spring portion 74c of the first flexible portion 74. Furthermore, even if the position of the second electrode terminal BCa shifts within the range of the design tolerance due to thermal expansion or thermal contraction of the other battery cell BC during use of the battery module BM, the bus bar 7 of this specific example 7 can accommodate the positional shift of the second electrode terminal BCa within the range of the design tolerance due to thermal expansion or thermal contraction of the other battery cell BC by absorbing the positional shift with the first spring portion 76b and the second spring portion 76c of the second flexible portion 76.

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

[0088] Furthermore, in the busbar 7 of this specific example 7, the busbar body 70 is formed into a flat plate, and the first spring portion 74b and the second spring portion 74c of the first flexible portion 74, which constitutes the tolerance absorbing structure, are provided on the first terminal connector 71, which is located away from the central portion of the busbar body 70, and the first spring portion 76b and the second spring portion 76c of the second flexible portion 76, which also constitutes the tolerance absorbing structure, are provided on the second terminal connector 72, which is located away from the central portion of the busbar body 70. Therefore, this busbar 7 can connect the first electrode terminal BCa and the second electrode terminal BCa via the shortest possible current path, thereby minimizing the resistance value and heat generation. Furthermore, the busbar 7 of this specific example 7 has a tolerance absorption structure (the first spring portion 74b and the second spring portion 74c of the first flexible portion 74, and the first spring portion 76b and the second spring portion 76c of the second flexible portion 76) at the welding point with the electrode terminal BCa, which has the greatest temperature reduction effect due to heat dissipation from the battery cell BC, so that heat generation by the busbar itself can be suppressed and the heat-resistant structure (i.e., the cross-sectional area of the central part of the busbar main body 70) can be made smaller.

[0089] Furthermore, in the bus bar 7 of this specific example 7, the second spring portions 74c, 76c may not be provided, and in this case, the function of absorbing the positional deviation of the electrode terminal BCa caused by the second spring portions 74c, 76c may be performed by the first spring portions 74b, 76b.

[0090] [Transformation] A modified embodiment of the bus bar according to the present invention will be described with reference to FIGS.

[0091] The busbar of this modified embodiment includes a first busbar body formed in a flat plate shape. This first busbar body is disposed between adjacent battery cells BC. The busbar of this modified embodiment further includes a second busbar body that is physically and electrically connected to the first busbar body.

[0092] The first busbar body has a cutout or through-hole portion that exposes the first electrode terminal BCa of one of the battery cells BC, and is divided into a first terminal connector to which the first electrode terminal BCa is electrically connected via the second busbar body, and a second terminal connector to which the second electrode terminal BCa of the other battery cell BC is to be welded.

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

[0094] The bus bar of this modified embodiment includes the first bus bar body and the second bus bar body having such shapes, and the first and second spring portions of the second bus bar body function as a tolerance absorbing structure. For example, even if the spacing in the arrangement direction (so-called inter-terminal pitch) between the electrode terminals BCa of two adjacent battery cells BC deviates within the design tolerance range, this bus bar can be welded to each electrode terminal BCa by absorbing the deviation in the inter-terminal pitch with the first and second spring portions. Furthermore, even if the inter-terminal pitch shifts within the design tolerance range or the position of the electrode terminals BCa shifts within the design tolerance range due to thermal expansion or thermal contraction of the battery cells BC during use of the battery module BM, the first spring portion and the second spring portion absorb the inter-terminal pitch shift or positional shift of the electrode terminals BCa, thereby allowing the bus bar to follow the inter-cell pitch shift within the design tolerance range due to thermal expansion or thermal contraction of the battery cells BC and the positional shift of the electrode terminals BCa within the design tolerance range due to thermal expansion or thermal contraction of the battery cells BC.

[0095] In this modified busbar, the first and second spring portions (tolerance absorbing structure) of the second busbar body are provided in a location that avoids the central portion between the first and second terminal connectors in the first busbar body, allowing the central portion to have a heat-resistant structure without being bound by the tolerance absorbing structure.Furthermore, in this modified busbar, the first and second spring portions (tolerance absorbing structure) are provided at the welding points with the electrode terminals BCa where the temperature reduction effect due to heat dissipation from the battery cells BC is greatest, thereby suppressing heat generation in the first busbar body and enabling the heat-resistant structure (i.e., the cross-sectional area of the central portion of the first busbar body) to be made smaller.

[0096] A specific example of the bus bar of this modified embodiment will be described below.

[0097] [Example 1] Reference numeral 101 in Fig. 12 denotes a busbar of specific example 1 in this modified embodiment. This busbar 101 includes a first busbar body 110 formed into a flat plate shape from a conductive material such as metal, and a second busbar body 120 that is physically and electrically connected to this first busbar body 110 (Fig. 12).

[0098] The first busbar body 110 is formed in a rectangular flat plate shape. The first busbar body 110 is divided into a rectangular flat plate-shaped 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-shaped second terminal connector 112 to which the second electrode terminal BCa of the other battery cell BC is to be welded (FIG. 12). The first terminal connector 111 of this specific example 1 has a notch 111a that exposes the first electrode terminal BCa.

[0099] In this first busbar main body 110, the second busbar main body 120 is assembled to the first terminal connector 111, and a portion of the second busbar main body 120 disposed in the cutout portion 111a is welded to the first electrode terminal BCa of one battery cell BC by laser welding or the like. 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, as in the conventional method. The cutout portion 111a is thus superimposed on the first electrode terminal BCa, exposing the first electrode terminal BCa. The cutout portion 111a is formed in a rectangular shape that is larger than the first electrode terminal BCa, exposing the entire flat surface (welding surface) of the first electrode terminal BCa. The cutout portion 111a shown here is cut out in a rectangular shape from a side of the first terminal connector 111 in the arrangement direction of the multiple battery cells BC toward the second terminal connector 112. The second terminal connector 112 may be provided with a through hole for welding.

[0100] The second busbar body 120 is disposed in the cutout portion 111a of the first terminal connector 111 of the first busbar body 110, and has a terminal weld portion 121 welded to the first electrode terminal BCa, a first busbar weld portion 122 welded to the first terminal connector 111, and a second busbar weld portion 123 welded to the first terminal connector 111 (FIG. 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 arrangement direction of the terminal weld portion 121 and the first busbar weld portion 122 and 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 arrangement direction of the terminal weld portion 121 and the second busbar weld portion 123 and the opposite direction (FIG. 12). Furthermore, the second busbar body 120 has a circuit conductor connection portion 126 that physically and electrically connects to a circuit conductor (here, the wiring pattern of a flexible printed circuit board) that is electrically connected to the battery monitoring unit (Figure 12).

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

[0102] This second busbar body 120 is formed, for example, by bending a rectangular flat-plate piece, and a rectangular flat-plate first busbar weld 122 and a rectangular flat-plate second busbar weld 123 are welded to the first terminal connector 111. In the first terminal connector 111 shown here, pieces are formed on one side and the other side of the notch 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 122 is welded to one side of the second busbar body 120, and the second busbar weld 123 is welded to the other side of the second busbar body 120 ( FIG. 12 ).

[0103] In the first bus bar welded portion 122, the side portion on the terminal welded portion 121 side (i.e., the second bus bar welded portion 123 side) is overlapped with the cutout portion 111a. The first spring portion 124 is formed in a V-shape or a U-shape by rising from the side portion of the first bus bar welded portion 122 in the direction opposite to the first electrode terminal BCa side and folding back at the end toward the first electrode terminal BCa side (FIG. 12). In the second bus bar welded portion 123, the side portion on the terminal welded portion 121 side (i.e., the first bus bar welded portion 122 side) is overlapped with the cutout portion 111a. The second spring portion 125 is formed in a V-shape or a U-shape by rising from the side portion of the second bus bar welded portion 123 in the direction opposite to the first electrode terminal BCa side and folding back at the end toward the first electrode terminal BCa side (FIG. 12). The first spring portion 124 and the second spring portion 125 are flexibly deformed in a direction perpendicular to the arrangement direction of the multiple battery cells BC. The terminal welding portion 121 connects the ends of the first spring portion 124 and the second spring portion 125 that are folded back toward the first electrode terminal BCa (FIG. 12). The terminal welding portion 121 shown here is formed in a disk shape that is 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 (FIG. 12).

[0104] In this specific example 1, even if the position of the first electrode terminal BCa or the second electrode terminal BCa shifts within the range of the design tolerance due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 101 can accommodate the positional shift of the electrode terminal BCa within the range of the design tolerance due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC by absorbing the positional shift of the electrode terminal BCa with the first spring portion 124 and the second spring portion 125.

[0105] In addition, in the busbar 101 of this specific example 1, the first busbar body 110 is formed into a flat plate shape, and then the second busbar body 120 with a tolerance absorption structure (first spring portion 124 and second spring portion 125) is assembled to the first terminal connector 111, which is obtained by removing the central portion between the first terminal connector 111 and the second terminal connector 112 in the first busbar body 110. Therefore, in this busbar 101, the first electrode terminal BCa and the second electrode terminal BCa can be connected via the shortest possible current path, thereby minimizing the resistance value and heat generation. Furthermore, the busbar 101 of this specific example 1 has a tolerance absorption structure (first spring portion 124 and second spring portion 125) at the welding point with the electrode terminal BCa, which has the greatest temperature reduction effect due to heat dissipation from the battery cell BC, so that heat generation in the first busbar main body 110 can be suppressed and the heat-resistant structure (i.e., the cross-sectional area of the central part of the first busbar main body 110) can be made smaller.

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

[0107] [Example 2] Reference numeral 201 in Fig. 14 denotes a bus bar of specific example 2 in this modified embodiment. This bus bar 201 includes a first bus bar body 210 formed into a flat plate shape from a conductive material such as metal, and a second bus bar body 220 that is physically and electrically connected to this first bus bar body 210 (Fig. 14).

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

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

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

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

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

[0113] In the first bus bar weld portion 222, the side portion on the terminal weld portion 221 side is overlapped with the cutout portion 211a. The first spring portion 224 is formed in a V-shape or a U-shape by rising from the side portion of the first bus bar weld portion 222 in the opposite direction from the first electrode terminal BCa side and folding back at the end toward the first electrode terminal BCa side (FIG. 14). The first spring portion 224 is flexibly deformed in the arrangement direction of the multiple battery cells BC. In addition, in the second bus bar weld portion 223, the side portion on the terminal weld portion 221 side is overlapped with the cutout portion 211a. The second spring portion 225 is formed in a V-shape or a U-shape by rising from the side portion of the second bus bar weld portion 223 in the opposite direction from the first electrode terminal BCa side and folding back at the end toward the first electrode terminal BCa side (FIG. 14). The second spring portion 225 is flexibly deformed in a direction perpendicular to the arrangement direction of the multiple battery cells BC. The terminal welding portion 221 connects the end of the first spring portion 224 that is folded back toward the first electrode terminal BCa to the end of the second spring portion 225 that is folded back toward the first electrode terminal BCa (FIG. 14). The terminal welding portion 221 shown here is formed in a disk shape that is 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 welding portion 223 and protrudes from the first busbar main body 210 (FIG. 14).

[0114] Even if the positions of the first electrode terminals BCa and the second electrode terminals BCa shift within the range of the design tolerance due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 201 of this specific example 2 can accommodate the positional shift of the electrode terminals BCa within the range of the design tolerance due to thermal expansion or thermal contraction of the one battery cell BC or the other battery cell BC by absorbing the positional shift of the electrode terminals BCa with the first spring portions 224 and the second spring portions 225. Furthermore, even if the inter-terminal pitch shifts within the range of the design tolerance due to thermal expansion or thermal contraction of one battery cell BC or the other battery cell BC during use of the battery module BM, the bus bar 201 of this specific example 2 can accommodate the inter-cell pitch shift within the range of the design tolerance due to thermal expansion or thermal contraction of the one battery cell BC or the other battery cell BC by absorbing the misalignment of the terminal pitch with the first spring portions 224.

[0115] In addition, in the busbar 201 of this specific example 2, the first busbar body 210 is formed into a flat plate shape, and then the second busbar body 220 with a tolerance absorption structure (first spring portion 224 and second spring portion 225) is assembled to the first terminal connector 211, which is obtained by removing the central portion between the first terminal connector 211 and the second terminal connector 212 in the first busbar body 210. Therefore, in this busbar 201, the first electrode terminal BCa and the second electrode terminal BCa can be connected by the shortest possible current path, thereby minimizing the resistance value and the amount of heat generated. Furthermore, the busbar 201 of this specific example 2 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, which has the greatest temperature reduction effect due to heat dissipation from the battery cell BC, so that heat generation in the first busbar main body 210 can be suppressed and the heat-resistant structure (i.e., the cross-sectional area of the central part of the first busbar main body 210) can be made smaller. [Explanation of symbols]

[0116] 1,2,3,4,5,6,7,101,201 Bus bar 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 welding part 14b, 24b, 34b, 36b, 44b, 54b, 64b, 74b, 76b First spring part (spring part) 110,210 First bus bar body 111,211 First terminal connector 111a,211a Notch 112,212 Second terminal connector 120,220 Second bus bar body 121,221 Terminal welding part 122,222 First bus bar weld 123,223 Second bus bar weld 124,224 First spring part 125,225 Second spring part 126,226 Circuit conductor connections

Claims

1. a busbar main 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 to be welded to a first electrode terminal of one of the battery cells, and a second terminal connector to be welded to a 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 an electrode terminal to be welded, and a flexible portion that protrudes from an outer peripheral edge of the through hole toward a center of the hole and has flexibility; the flexible portion includes a terminal welding portion that is welded to an electrode terminal to be welded, and a spring portion that is provided between the terminal welding portion and a fixed end on the outer peripheral edge side of the through hole and is elastically deformable in its own protruding direction and in the opposite direction.

2. the flexible portion is formed in a cantilever shape that protrudes from an outer peripheral edge of the through hole toward a center of the through hole in a direction perpendicular to an arrangement direction of the plurality of battery cells, The busbar according to claim 1 , wherein the terminal welding portion is provided at a free end of the flexible portion.

3. the flexible portion is formed in a cantilever shape that protrudes from an outer peripheral edge of the through hole toward a center of the through hole in an arrangement direction of the plurality of battery cells, The busbar according to claim 1 , wherein the terminal welding portion is provided at a free end of the flexible portion.

4. 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 that protrudes from an outer peripheral edge portion of the first through hole toward a center of the hole in a direction perpendicular to an arrangement direction of the plurality of battery cells, the terminal welding portion of the first flexible portion is provided at a 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 an outer peripheral edge of the second through hole toward a center of the hole in the arrangement direction, The busbar according to claim 1 , wherein the terminal welding portion of the second flexible portion is provided at a free end of the second flexible portion and is welded to the second electrode terminal.

5. 5. The bus bar according to claim 2, wherein the flexible portions are provided as a pair, with the flexible portions protruding in opposite directions.

6. 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 circumferential direction of the through hole, The busbar according to claim 1 , wherein the terminal welding portion is provided at a free end of the flexible portion.

7. the flexible portion is formed in a doubly supported beam shape that protrudes from two opposing locations on the outer periphery of the 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 is disposed at the center of the flexible portion and at the center of the through hole, The busbar according to claim 1 , wherein 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.

8. the flexible portion is formed in a double-supported beam shape that protrudes from two opposing locations on the outer periphery of the through hole toward the center of the hole in the arrangement direction of the plurality of battery cells, the terminal welding portion is disposed at the center of the flexible portion and at the center of the through hole, The busbar according to claim 1 , wherein 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.

9. 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 doubly supported beam shape that protrudes from two opposing locations on an outer periphery of the first through hole toward a center of the hole in a direction perpendicular to an arrangement direction of the plurality of battery cells, the terminal welding portion of the first flexible portion is disposed at a center of the first flexible portion and at a 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 welding portion and one fixed end of the first flexible portion and between the terminal welding portion and the other fixed end of the first flexible portion, the second flexible portion is formed in a doubly supported beam shape that protrudes from two opposing positions on an outer periphery of the second through hole in the arrangement direction toward a center of the hole, the terminal welding portion of the second flexible portion is disposed at a center of the second flexible portion and at a center of the second through hole, and is welded to the second electrode terminal; 2. The busbar according to claim 1, wherein 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 of the second flexible portion.

10. 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 bus bar body physically and electrically connected to the first bus bar body; Equipped with the first busbar body has a cutout portion or a through-hole portion that exposes a 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; the second busbar body is disposed in the notch or the through-hole of the first terminal connector, and includes: a terminal weld portion welded to the first electrode terminal, a first busbar weld portion welded to the first terminal connector, a second busbar weld portion welded to the first terminal connector, a first spring portion provided between the terminal weld portion and the first busbar weld portion and elastically deformable in an arrangement direction of the terminal weld portion and the first busbar weld portion and in the opposite direction; a second spring portion provided between the terminal weld portion and the second busbar weld portion and elastically deformable in an arrangement direction of the terminal weld portion and the second busbar weld portion and in the opposite direction; and a circuit conductor connection portion for physically and electrically connecting the second busbar body to a circuit conductor that is electrically connected to a battery monitoring unit.

11. 11. The busbar according to claim 10, wherein the second busbar body is arranged such that the first busbar weld portion, the first spring portion, the terminal weld portion, the second spring portion, and the second busbar weld portion are aligned in a line in that order, and the alignment direction is oriented in the arrangement direction of the plurality of battery cells or in a direction perpendicular to the arrangement direction of the plurality of battery cells, and the second busbar body is connected to the first busbar body.

12. 11. The busbar according to claim 10, wherein the second busbar body is arranged such that the first busbar weld portion, the first spring portion, and the terminal weld portion are aligned in that order in a first direction, and the terminal weld portion, the second spring portion, and the second busbar weld portion are aligned in that order in a second direction perpendicular to the first direction, and the first direction is oriented in a direction in which the plurality of battery cells are arranged, and the second direction is oriented in a direction perpendicular to the direction in which the plurality of battery cells are arranged, and the second busbar body is connected to the first busbar body.

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