Bus bar and wiring module

Abstract

This bus bar 10 comprises two connection parts 11 and a coupling part 12 for coupling and electrically connecting the two connection parts 11. The coupling part 12 comprises a first coupling part 12A and a second coupling part 12B different from the first coupling part 12A. The first coupling part 12A and the second coupling part 12B are configured to be elastically deformable. The coupling part 12 forms a conductive path between the two connection parts 11. The coupling part 12 is formed such that the cross-sectional area perpendicular to the conductive path is greater than the cross-sectional area perpendicular to the arrangement direction of the two connection parts 11.

Description

Busbar and wiring modules

[0001] The present disclosure relates to a busbar and a wiring module.

[0002] Energy storage modules for electric vehicles, hybrid vehicles, and the like include a large number of stacked energy storage elements, which are electrically connected in series or parallel by bus bars. A conventionally known example of such a bus bar is the connection bus bar described in Japanese Patent Laid-Open Publication No. 2019-207825 (Patent Document 1). The connection bus bar has a plurality of plate-shaped connection portions connected to electrode terminals of the energy storage elements. The plurality of connection portions are aligned in the left-right direction (longer side direction of the connection bus bar). Bent portions are formed between the plurality of connection portions in the connection bus bar, protruding in a direction away from the electrode terminals (upward). The bent portions are configured to be flexible and deformable in the longer side direction of the connection bus bar.

[0003] Japanese Patent Application Laid-Open No. 2019-207825

[0004] In the above-described connection busbar, the connection portions are directly connected to the electrode terminals of the energy storage elements, and adjacent connection portions are connected by bent portions. Therefore, when the energy storage module is used, a large current flows mainly through the bent portions. Therefore, as the capacity of the energy storage elements increases and the size of the connection busbar decreases, the amount of heat generated in the connection busbar, particularly at the bent portions, is likely to become excessive.

[0005] The busbar of the present disclosure comprises two connection portions and a connecting portion that connects and electrically connects the two connection portions, the connecting portions comprising a first connecting portion and a second connecting portion different from the first connecting portion, the first connecting portion and the second connecting portion being configured to be elastically deformable, the connecting portion forming a conductive path between the two connection portions, and a cross-sectional area of ​​the connecting portion perpendicular to the conductive path that is set to be larger than a cross-sectional area of ​​the connecting portion perpendicular to the arrangement direction of the two connection portions.

[0006] The wiring module of the present disclosure is a wiring module that is attached to a plurality of energy storage elements each having an electrode terminal, and includes the above-mentioned bus bar, the connection portion of which is connected to the electrode terminal, a voltage detection wire electrically connected to the bus bar, and a protector that holds the bus bar and the voltage detection wire.

[0007] According to the present disclosure, the amount of heat generated by the bus bar can be reduced.

[0008] FIG. 1 is a perspective view of a busbar according to the first embodiment. FIG. 2 is an exploded perspective view of the busbar according to the first embodiment. FIG. 3 is a front view of the busbar according to the first embodiment. FIG. 4 is a cross-sectional view taken along line A-A in FIG. 3. FIG. 5 is a plan view of the energy storage module according to the first embodiment. FIG. 6 is a perspective view of a busbar according to a modified example of the first embodiment. FIG. 7 is a perspective view of a busbar according to the second embodiment. FIG. 8 is an exploded perspective view of the busbar according to the second embodiment. FIG. 9 is a cross-sectional view of the energy storage module according to the second embodiment, taken along the arrangement direction of the busbars. FIG. 10 is a perspective view of a busbar according to a modified example of the second embodiment.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. [1] A busbar according to the present disclosure includes two connection portions and a coupling portion that couples and electrically connects the two connection portions, the coupling portions including a first coupling portion and a second coupling portion different from the first coupling portion, the first coupling portion and the second coupling portion being configured to be elastically deformable, the coupling portion forming a conductive path between the two connection portions, and a cross-sectional area of ​​the coupling portion perpendicular to the conductive path being set larger than a cross-sectional area of ​​the coupling portion perpendicular to an arrangement direction of the two connection portions.

[0010] According to this configuration, the cross-sectional area of ​​the connecting portion that connects the two connecting portions is set to be larger than the cross-sectional area of ​​the connecting portion, which makes it easier to suppress heat generation in the connecting portion.

[0011] [2] In the above [1], it is preferable that a gap is formed between the first connecting portion and the second connecting portion.

[0012] With this configuration, compared to when the first connecting portion and the second connecting portion are arranged overlapping each other, the first connecting portion and the second connecting portion are each more likely to transfer heat to the surrounding air, making it easier for the first connecting portion and the second connecting portion to dissipate heat.

[0013] [3] The wiring module of the present disclosure is a wiring module attached to a plurality of energy storage elements each having an electrode terminal, and includes a bus bar of the above [1] or [2], the connection portion of which is connected to the electrode terminal, a voltage detection wire electrically connected to the bus bar, and a protector that holds the bus bar and the voltage detection wire.

[0014] [Details of the Embodiments of the Present Disclosure] The following describes embodiments of the present disclosure. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. In the drawings, for the convenience of explanation, some components may be exaggerated or simplified. Furthermore, the dimensional ratios of each part may differ between drawings. In this specification, "orthogonal" does not only refer to a strict orthogonal relationship, but also includes a roughly orthogonal relationship within the scope of the operation and effect of this embodiment.

[0015] In addition, "facing" in this specification refers to surfaces or components facing each other, and includes not only cases where they are completely facing each other, but also cases where they are partially facing each other. In addition, "facing" in this specification includes both cases where a component separate from the two components is interposed between the two components, and cases where nothing is interposed between the two components.

[0016] In each drawing, three mutually perpendicular directions are shown, and the three directions are respectively indicated as a first direction D1, a second direction D2, and a third direction D3. That is, the first direction D1 and the second direction D2 are perpendicular to each other, the first direction D1 and the third direction D3 are perpendicular to each other, and the second direction D2 and the third direction D3 are perpendicular to each other. By drawing arrows on both sides of the solid line indicating each direction, not only the direction of the arrow on the side with the symbol but also the direction of the arrow on the side without the symbol is considered to indicate the corresponding direction.

[0017] First Embodiment A first embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 5. In the following description, when multiple identical components are used, only some of the components may be designated by reference numerals, and the reference numerals for the other components may be omitted.

[0018] (Busbar 10) The busbar 10 is formed by processing a conductive metal plate. The metal constituting the busbar 10 is, for example, copper, a copper alloy, aluminum, an aluminum alloy, or the like. As shown in Fig. 2, the busbar 10 of this embodiment is composed of a first member 10A and a second member 10B that are separate from each other. The configurations of the first member 10A and the second member 10B will be described later.

[0019] 1 , busbar 10 includes two connection portions 11 and a coupling portion 12 that couples and electrically connects the two connection portions 11. Below, the configuration of busbar 10 will be described, with the arrangement direction of the two connection portions 11 (longer side direction of busbar 10) as a first direction D1, the width direction (short side direction) of busbar 10 as a second direction D2, and the thickness direction of connection portions 11 as a third direction D3.

[0020] The connection portion 11 has a thin plate shape in the third direction D3. The connection portion 11 has, for example, a rectangular shape when viewed from the third direction D3. The two connection portions 11 are arranged side by side with a gap in the first direction D1. A through hole 11A is formed in the center of the connection portion 11. The through hole 11A penetrates the connection portion 11 in the third direction D3. As will be described later, the connection portion 11 is connected to the electrode terminal 2A of the energy storage element 2 by, for example, welding (see FIG. 5 ). The through hole 11A is used to confirm the position of the electrode terminal 2A arranged opposite the connection portion 11 in the third direction D3. Unlike the present embodiment, the connection portion may have, for example, an insertion hole through which a bolt-shaped electrode terminal is inserted. The connection portion and the electrode terminal may be electrically connected by fastening a nut to the electrode terminal inserted into the insertion hole.

[0021] 1 and 3 , the coupling portion 12 includes a first coupling portion 12A and a second coupling portion 12B different from the first coupling portion 12A. The first coupling portion 12A and the second coupling portion 12B each couple and electrically connect two connection portions 11. At least one of the first coupling portion 12A and the second coupling portion 12B and the two connection portions 11 form a plate shape that is continuous in the arrangement direction of the two connection portions 11 (first direction D1). For example, the first coupling portion 12A and the two connection portions 11 form a seamless plate shape that is continuous in the first direction D1.

[0022] The conductive path between the two connection parts 11 formed by the coupling part 12 includes a first conductive path formed by the first coupling part 12A and a second conductive path different from the first conductive path and formed by the second coupling part 12B. Note that the first conductive path and the second conductive path may have a partially overlapping path.

[0023] As shown in FIG. 4 , the dimensions (width dimensions) of the first connecting portion 12A and the second connecting portion 12B in the second direction D2 are, for example, the same and are equal to the width dimension of the connecting portion 11. As shown in FIG. 3 , the first connecting portion 12A and the second connecting portion 12B are arranged, for example, overlapping in the third direction D3. In this embodiment, a gap 13 is formed between the first connecting portion 12A and the second connecting portion 12B. By providing the gap 13, the first connecting portion 12A and the second connecting portion 12B are arranged spaced apart from each other. The gap 13 is open in the second direction D2. In other words, the gap 13 is not defined in the second direction D2.

[0024] The first connecting portion 12A and the second connecting portion 13B are, for example, plate-shaped and bent relative to the connecting portion 11 so as to protrude in the second direction D2. The first connecting portion 12A and the second connecting portion 12B are formed in a mountain shape relative to the connecting portion 11. This allows the first connecting portion 12A and the second connecting portion 12B to be elastically deformable. Furthermore, by providing a gap 13 between the first connecting portion 12A and the second connecting portion 12B, the first connecting portion 12A and the second connecting portion 12B do not interfere with each other and can elastically deform independently.

[0025] The elastic deformation of the first connecting portion 12A and the second connecting portion 12B allows a certain degree of relative displacement between the two connecting portions 11. The first connecting portion 12A and the second connecting portion 12B can allow relative displacement in the arrangement direction (first direction D1) of the two connecting portions 11. The first connecting portion 12A and the second connecting portion 12B can also allow relative displacement in the thickness direction (third direction D3) of the two connecting portions 11.

[0026] In this embodiment, the first coupling portion 12A and the second coupling portion 12B are configured to protrude in the same direction (upward in FIG. 3 ) in the third direction D3 relative to the connection portion 11. This configuration allows the dimension of the busbar 10 in the third direction D3 to be reduced.

[0027] FIG. 4 shows cross sections of the coupling portion 12 and the connecting portion 11, perpendicular to the first direction D1. The cross-sectional area S1 of the coupling portion 12 is composed of the cross-sectional area S1A of the first coupling portion 12A and the cross-sectional area S1B of the second coupling portion 12B. Here, the thicknesses of the coupling portion 11 and the first coupling portion 12A are the same. The widths of the coupling portion 11 and the first coupling portion 12A are also the same. Therefore, the cross-sectional area S2 of the coupling portion 11 is equal to the cross-sectional area S1A of the first coupling portion 12A. Therefore, the cross-sectional area S1 of the coupling portion 12 is larger than the cross-sectional area S2 of the coupling portion 11. Note that in this specification, the cross-sectional area S1 of the coupling portion 12 does not have to be the area of ​​a cross section perpendicular to the first direction D1 (the arrangement direction of the connecting portions 11), but may be the area of ​​a cross section perpendicular to the conductive path formed by the coupling portion 12, including the cross sections of the first coupling portion 12A and the second coupling portion 12B. The cross-sectional area S2 of the connection portion 11 is limited to the area of ​​a cross section perpendicular to the first direction D1.

[0028] As shown in FIG. 2 , the first member 10A and the second member 10B are each formed by bending a metal plate. The width dimensions of the first member 10A and the second member 10B are, for example, the same. The thicknesses of the first member 10A and the second member 10B may or may not be the same. The first member 10A has two connection portions 11 and a first linking portion 12A. The second member 10B has two joint portions 14 and a second linking portion 12B that links the two joint portions 14. Each joint portion 14 is joined by welding or the like to a portion of each connection portion 11 near the first linking portion 12A.

[0029] (Wiring Module 3) As shown in Fig. 5 , the bus bar 10 of this embodiment is included in an energy storage module 1 mounted on a vehicle such as an electric vehicle or a hybrid vehicle. The energy storage module 1 includes a plurality of energy storage elements 2 each having an electrode terminal 2A, and a wiring module 3 attached to the plurality of energy storage elements 2. The wiring module 3 includes the bus bar 10, a flexible printed circuit board 20 (an example of a voltage detection wire) electrically connected to the bus bar 10, and a protector 30 that holds the bus bar 10 and the flexible printed circuit board 20. For simplicity, the configuration of the energy storage module 1 (the energy storage elements 2 and the wiring module 3) will be described below with the lower side in Fig. 5 defined as the front, the upper side defined as the rear, the left-right direction defined as the left-right direction, and the front side in the direction perpendicular to the plane of the page defined as the top.

[0030] The energy storage element 2 has a rectangular parallelepiped shape. The energy storage element 2 is thin in the left-right direction and long in the front-rear direction. Electrode terminals 2A are provided at the front and rear ends of the upper surface of the energy storage element 2. One of the two electrode terminals 2A of the energy storage element 2 is a positive electrode, and the other is a negative electrode. The energy storage element 2 is not particularly limited and may be a secondary battery or a capacitor. The energy storage element 2 in this embodiment is a secondary battery. A plurality of energy storage elements 2 are stacked in the left-right direction. A spacer (not shown) is arranged between adjacent energy storage elements 2.

[0031] The wiring module 3 is attached to the front and rear portions of the upper surfaces of the plurality of energy storage elements 2. Fig. 5 illustrates the wiring module 3 attached to the front portions of the upper surfaces of the plurality of energy storage elements 2. The wiring module 3 attached to the rear portions of the upper surfaces of the plurality of energy storage elements 2 is not illustrated, but is configured similarly to the wiring module 3 illustrated in Fig. 5.

[0032] The protector 30 is made of insulating synthetic resin. The protector 30 includes a busbar accommodating section 31 that accommodates the busbar 10 and a board accommodating section 32 that accommodates the flexible printed circuit board 20. The busbar accommodating section 31 is frame-shaped and arranged side by side in the left-right direction. A connection hole (not shown) is provided in the bottom wall of the busbar accommodating section 31. The connection portion 11 of the busbar 10 is connected to the electrode terminal 2A through this connection hole. The board accommodating section 32 is groove-shaped and extends in the left-right direction. The board accommodating section 32 is located behind the busbar accommodating section 31. A notch 31A is formed in the wall of the busbar accommodating section 31 that is located closer to the board accommodating section 32. A metal piece 40 that electrically connects the busbar 10 and the flexible printed circuit board 20 is located in the notch 31A. The metal piece 40 and the busbar 10 are connected by welding, for example. The metal piece 40 and the flexible printed circuit board 20 are connected by soldering, for example. The wiring module 3 may include a cover (not shown) that covers the protector 30 that holds the bus bar 10 and the flexible printed circuit board 20 .

[0033] The flexible printed circuit board 20 includes a sheet-like member made of insulating synthetic resin and a plurality of conductive paths protected by the sheet-like member. One end of the conductive paths is electrically connected to the bus bar 10 via a small metal piece 40. The other end of the conductive paths is connected to an external ECU (Electronic Control Unit) or the like via a connector (not shown). The ECU is equipped with a microcomputer, elements, etc., and has a well-known configuration that has functions such as detecting the voltage, current, temperature, etc. of each storage element 2 and controlling the charge and discharge of each storage element 2.

[0034] In the wiring module 3, the connection portions 11 of the busbar 10 are disposed to face the electrode terminals 2A, and the connection portions 11 and the electrode terminals 2A are connected by welding. Furthermore, the linking portions 12 extend in a thickness direction of the linking portions 11 (third direction D3) away from the energy storage elements 2. The busbar 10 connects the electrode terminals 2A of adjacent energy storage elements 2. That is, the linking portions 12 form a conductive path between the two linking portions 11. Therefore, a large current flows through the linking portions 12 when the vehicle is in use. In this embodiment, as described above, the cross-sectional area S1 of the linking portions 12 is set larger than the cross-sectional area S2 of the connection portions 11. Therefore, heat generation in the linking portions 12 can be suppressed compared to, for example, a case in which the busbar is formed by processing a single metal plate and the cross-sectional area of ​​the linking portions is the same as the cross-sectional area of ​​the connecting portions. Because the linking portions 12 are portions of the busbar 10 that are particularly susceptible to heat generation, this embodiment can suppress heat generation in the busbar 10. Since the connection portion 11 is directly connected to the electrode terminal 2A, heat can be transferred from the connection portion 11 to the electrode terminal 2A.

[0035] In this embodiment, the gap 13 is formed between the first connecting portion 12A and the second connecting portion 12B, so that heat generated at the first connecting portion 12A and the second connecting portion 12B during use of the vehicle is transferred to the air disposed in the gap 13. As a result, the heat dissipation properties of the first connecting portion 12A and the second connecting portion 12B can be further improved.

[0036] In the busbar 10 of this embodiment, the elastic deformation of the connecting portions 12 allows the connection portions 11 to be displaced in the arrangement direction. Therefore, according to the arrangement shown in FIG. 5 , the connecting portions 12 allow the connection portions 11 to be displaced in the left-right direction. This allows for absorbing manufacturing tolerances and assembly tolerances of the energy storage elements 2 in the left-right direction. Furthermore, even if adjacent energy storage elements 2 are dynamically displaced in the left-right direction due to vehicle vibrations or the like, the elastic deformation of the connecting portions 12 makes it difficult for the connection portions 11 and the electrode terminals 2A to be damaged. Similarly, since the connecting portions 12 can also allow the connection portions 11 to be displaced in the thickness direction of the connection portions 11, the arrangement shown in FIG. 5 also allows for tolerances and fluctuations in the up-down direction of the energy storage elements 2.

[0037] (Action and effect of embodiment 1) (1-1) The busbar 10 according to embodiment 1 comprises two connection portions 11 and a connecting portion 12 that connects and electrically connects the two connection portions 11, the connecting portion 12 comprising a first connecting portion 12A and a second connecting portion 12B that is different from the first connecting portion 12A, the first connecting portion 12A and the second connecting portion 12B being configured to be elastically deformable, the connecting portion 12 forming a conductive path between the two connection portions 11, and a cross-sectional area S1 of the connecting portion 12 perpendicular to the conductive path being set larger than a cross-sectional area S2 of the connecting portion 11 perpendicular to the arrangement direction of the two connection portions 11.

[0038] With this configuration, the cross-sectional area S1 of the connecting portion 12 connecting the two connecting portions 11 is set to be larger than the cross-sectional area S2 of the connecting portion 11, making it easier to suppress heat generation in the connecting portion 12.

[0039] (1-2) In the first embodiment, the gap 13 is formed between the first connecting portion 12A and the second connecting portion 12B.

[0040] With this configuration, compared to when the first connecting portion 12A and the second connecting portion 12B are arranged overlapping each other, the first connecting portion 12A and the second connecting portion 12B are each more likely to transfer heat to the surrounding air, making it easier for the first connecting portion 12A and the second connecting portion 12B to dissipate heat.

[0041] (1-3) The wiring module 3 according to the first embodiment is a wiring module 3 that is attached to a plurality of energy storage elements 2, each having an electrode terminal 2A, and includes a bus bar 10 whose connection portion 11 is connected to the electrode terminal 2A, a voltage detection line (flexible printed circuit board 20) that is electrically connected to the bus bar 10, and a protector 30 that holds the bus bar 10 and the voltage detection line.

[0042] <Modification of First Embodiment> Fig. 6 shows a busbar 110 according to a modification of the first embodiment. While the busbar 10 is configured from a first member 10A and a second member 10B, a busbar according to the present disclosure may be configured from a single member, as in the busbar 110 of Fig. 6. That is, the first connecting portion 12A and the second connecting portion 12B may be integrally formed. The busbar 110 may be configured by extrusion molding, for example.

[0043] Second Embodiment A second embodiment of the present disclosure will be described with reference to Fig. 7 to Fig. 9. A bus bar 210 according to the second embodiment has the same configuration as that of the first embodiment except for the configuration of a connecting portion 212, and therefore, descriptions of the same components, functions, and effects as those of the first embodiment may be omitted.

[0044] As shown in FIG. 7 , the connecting portion 212 of the busbar 210 includes a first connecting portion 212A that protrudes from the connecting portion 11 toward one side (downward in the figure) in the third direction D3, and a second connecting portion 212B that protrudes from the connecting portion 11 toward the other side (downward in the figure) in the third direction D3. That is, the first connecting portion 212A and the second connecting portion 212B protrude in opposite directions from the connecting portion 11. With this configuration, compared to the first embodiment in which the first connecting portion 12A and the second connecting portion 12B protrude in the same direction from the connecting portion 11 (see FIG. 3 ), it is easier to increase the gap 13 between the first connecting portion 212A and the second connecting portion 212B. This allows more air to enter the gap 13. This improves the heat dissipation performance of the first connecting portion 212A and the second connecting portion 212B.

[0045] In the second embodiment, as shown in FIG. 8, the bus bar 210 is formed by joining a first member 210A and a second member 210B together, similar to the first embodiment.

[0046] FIG. 9 shows a cross-sectional view of a wiring module 203 (and an energy storage module 201) including a bus bar 210 and a protector 230. Note that in FIG. 9 , voltage detection wires and small metal pieces are omitted, and only the essential parts of the protector 230 are shown. The wiring module 203 may be configured such that the first connecting portion 212A (or the second connecting portion 212B) of the bus bar 210 is disposed between adjacent energy storage elements 2 in the first direction D1. The protector 230 may have an accommodating recess 231A capable of accommodating the first connecting portion 212A. In the energy storage module 201, a spacer 204 may be provided between two energy storage elements 2 in the first direction D1, while ensuring a space capable of arranging the accommodating recess 231A.

[0047] 10 shows a bus bar 310 according to a modification of the second embodiment. Like the bus bar 110 according to the modification of the first embodiment, the bus bar 310 is made of a single member by extrusion molding or the like.

[0048] Other Embodiments The above-described first and second embodiments can be modified as follows: The above-described first and second embodiments and the following modifications can be combined and implemented within the scope of technical compatibility.

[0049] In the first embodiment, the bus bar 10 has the through hole 11A. However, the through hole may be omitted.

[0050] In the first embodiment, the flexible printed circuit board 20 is used as the voltage detection line. However, the voltage detection line may be an electric wire, a flexible flat cable, or the like.

[0051] In the first embodiment, the bus bar 10 and the flexible printed circuit board 20 are indirectly connected via the metal pieces 40. However, the bus bar and the flexible printed circuit board may be directly connected.

[0052] 1: Energy storage module 2: Energy storage element 2A: Electrode terminal 3: Wiring module 10: Bus bar 10A: First member 10B: Second member 11: Connection portion 11A: Through hole 12: Linking portion 12A: First linking portion 12B: Second linking portion 13: Gap 13B: Second linking portion 14: Joint portion 20: Flexible printed circuit board (an example of a voltage detection wire) 30: Protector 31: Bus bar accommodating portion 31A: Cutout portion 32: Board accommodating portion 40: Small metal piece 110: Bus bar 201: Energy storage module 203: Wiring module 204: Spacer 210: Bus bar 210A: First member 210B: Second member 212: Linking portion 212A: First linking portion 212B: Second linking portion 230: Protector 231A: Receiving recess 310: Bus bar D1: First direction D2: Second direction D3: Third direction S1: Cross-sectional area of ​​coupling portion 12 S1A: Cross-sectional area of ​​first coupling portion 12A S1B: Cross-sectional area of ​​second coupling portion 12B S2: Cross-sectional area of ​​connection portion 11

Claims

1. A busbar comprising: two connection portions; and a coupling portion coupling and electrically connecting the two connection portions, the coupling portions comprising a first coupling portion and a second coupling portion different from the first coupling portion, the first coupling portion and the second coupling portion being configured to be elastically deformable, the coupling portions forming a conductive path between the two connection portions, and a cross-sectional area of ​​the coupling portion perpendicular to the conductive path is set to be larger than a cross-sectional area of ​​the coupling portion perpendicular to the arrangement direction of the two connection portions.

2. The busbar according to claim 1, wherein a gap is formed between the first connecting portion and the second connecting portion.

3. A wiring module to be attached to a plurality of energy storage elements each having an electrode terminal, comprising: a bus bar as described in claim 1 or claim 2, the connection portion of which is connected to the electrode terminal; a voltage detection wire electrically connected to the bus bar; and a protector that holds the bus bar and the voltage detection wire.

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