Joint structure of bus bar and electric wire

Abstract

To provide a joint structure of a bus bar and an electric wire capable of reducing the thickness of a joint part of the bus bar and the electric wire.SOLUTION: The joint portion of the bus bar includes a first thin region and a second thin region adjacent to the first thin region in a width direction of the bus bar, the first thin region is formed to be thin by removing a part of a surface on a bottom surface side of the bus bar, and the second thin region is formed to be thin by removing a part of a surface on an upper surface side of the bus bar. In the bonding portion of the bus bar, the plurality of strands of the electric wire are bonded to a bottom surface side of the first thin region and an upper surface side of the second thin region.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a joint structure between a bus bar and an electric wire. [Background technology]

[0002] Battery packs, which serve as power sources for electric vehicles, hybrid vehicles, and the like, are equipped with multiple battery modules. These battery modules are electrically connected using wiring materials such as high-voltage electrical wires or bus bars. High-voltage battery packs typically have many stacked battery cells, which are electrically connected in series or parallel by wiring modules (see Patent Document 1). In particular, with molded products such as bus bars, it becomes difficult to control the dimensional tolerances during manufacturing when they are made long. Therefore, the dimensional tolerances are absorbed by using wiring materials in which electric wires and bus bars are connected by welding or the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-55393 Summary of the Invention [Problem to be solved by the invention]

[0004] When joining an electric wire and a bus bar by welding or the like, if the conductor of the electric wire is positioned above the joint of the bus bar, the thickness of the joint between the bus bar and the electric wire increases by the thickness of the conductor of the electric wire. As a result, the height dimension of the wiring material increases, limiting the space available inside the vehicle. Although the increase in the thickness of the conductor of the electric wire is only a small increase in size, it is a major problem in a vehicle where space is limited.

[0005] The present invention has been made in view of the problems inherent in the conventional technology, and an object of the present invention is to provide a joint structure between a bus bar and an electric wire that enables a reduction in the thickness of the joint between the bus bar and the electric wire. [Means for solving the problem]

[0006] A joint structure between a busbar and an electric wire according to one embodiment of the present invention includes a plate-shaped busbar and a flat-shaped electric wire having a plurality of strands joined to a joint at one end of the busbar, wherein the joint of the busbar includes a first thin-walled region and a second thin-walled region adjacent to the first thin-walled region in the width direction of the busbar, wherein the first thin-walled region is formed thin by removing a portion of the surface on the bottom side of the busbar, and the second thin-walled region is formed thin by removing a portion of the surface on the top side of the busbar, and at the joint of the busbar, the plurality of strands of the electric wire are joined to the bottom side of the first thin-walled region and the top side of the second thin-walled region. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a joint structure between a bus bar and an electric wire, which can reduce the thickness of the joint portion between the bus bar and the electric wire. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view illustrating an example of a joining structure between a bus bar and an electric wire according to an embodiment of the present invention. [Figure 2A] FIG. 2 is a top view of the bus bar according to the embodiment. [Figure 2B] FIG. 2B is a side view of the bus bar shown in FIG. 2A. [Figure 2C] FIG. 2B is an end view of the bus bar shown in FIG. 2A. [Figure 3A] FIG. 2 is a side view showing a state before the bus bar and the electric wire are joined together. [Figure 3B] FIG. 10 is a side view showing a state after the bus bar and the electric wire are joined together. [Figure 4A] 3 is an enlarged side view showing a joint portion in the joint structure between the bus bar and the electric wire according to the embodiment. FIG. [Figure 4B] FIG. 10 is an enlarged side view showing a joint portion in a conventional joint structure between a bus bar and an electric wire. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a joining structure between a bus bar and an electric wire according to this embodiment will be described in detail with reference to the drawings. Note that the dimensional proportions in the drawings are exaggerated for the sake of convenience and may differ from the actual proportions.

[0010] The joint structure between a busbar and an electric wire according to this embodiment includes a plate-shaped busbar and a flat electric wire having multiple strands joined to a joint at one end of the busbar. The joint of the busbar includes a first thin-walled region and a second thin-walled region adjacent to the first thin-walled region in the width direction of the busbar. The first thin-walled region is formed by removing a portion of the bottom surface of the busbar, making it thinner, and the second thin-walled region is formed by removing a portion of the top surface of the busbar, making it thinner. At the joint of the busbar, the multiple strands of the electric wire are joined to the bottom side of the first thin-walled region and the top side of the second thin-walled region.

[0011] 1, the joint structure between a busbar and an electric wire in this embodiment is formed by joining an electric wire 10 to a busbar 20. Here, in this specification, the bottom side of busbar 20 refers to the side facing forward in the plane of FIG. 1, and the top side refers to the side facing backward in the plane of FIG. 1.

[0012] The electric wire 10 is formed by covering a conductor wire made up of a plurality of wires 12 with a covering 14, and the covering 14 is stripped at the end to expose the conductor wire. The conductor wire is made up of a plurality of wires. The material of the wires is not particularly limited and can be determined appropriately depending on the application. Known conductive metal materials such as copper, copper alloy, aluminum, and aluminum alloy can be used as the material of the wires. In this embodiment, the electric wire 10 has a flat shape. The flat shape can have a rectangular cross section, as shown in FIG. 1.

[0013] Busbar 20 is a plate-shaped member with a rectangular cross section, and is made of a metal (including an alloy) such as copper or aluminum. Busbar 20 has a joint 22 at one end that joins with electric wire 10 (strands 12) and a terminal 26 at the other end that is connected to a connector of another electronic device, and the portions other than joint 22 and terminal 26 are covered with insulating resin 24. In other words, joint 22 and terminal 26 of busbar 20 are not covered with insulating resin 24 and are exposed to the outside. The joint 22 of the bus bar 20 will be described in detail below with reference to FIGS. 2A to 2C.

[0014] The joint 22 of the busbar 20 includes a first thin-walled region 22A and a second thin-walled region 22B adjacent to each other in the width direction of the busbar 20 (see FIG. 2A). The first thin-walled region 22A is formed by removing a portion of the bottom surface of the busbar 20, thereby making it thinner, and the second thin-walled region is formed by removing a portion of the top surface of the busbar 20, thereby making it thinner (see FIG. 2C). That is, the joint 22 of the busbar 20 includes two regions, the first thin-walled region 22A and the second thin-walled region, separated by the central axis extending in the longitudinal direction of the busbar 20. The first thin-walled region 22A has a rectangular removal on the bottom surface side, and the second thin-walled region 22B has a rectangular removal on the top surface side (see FIG. 2C).

[0015] There are no particular limitations on the method for forming first thin region 22A and second thin region 22B in bus bar 20. For example, a plate-shaped bus bar can be prepared, and first thin region 22A can be formed by chamfering the bottom surface side of the end of the bus bar, and second thin region 22B can be formed by chamfering the top surface side.

[0016] Next, joining the wires 12 of the electric wire 10 to the joint portion 22 of the busbar 20 will be described. First, when joining the wires 12 of the electric wire 10 to the joint portion 22 of the busbar 20, the ends of the wires 12 of the electric wire 10 are brought into opposition to the joint portion 22 of the busbar 20 ( FIG. 3A ). Next, half of the wires 12 of the electric wire 10 are brought into contact with the bottom surface of the first thin-walled region 22A of the joint portion 22 of the busbar 20, and the remaining half of the wires 12 are brought into contact with the top surface of the second thin-walled region 22B. In this state, the wires 12 are distributed into two regions in the thickness direction, and therefore, as shown in FIG. 3B , the wires 12 of the electric wire 10 do not protrude outward in the thickness direction of the busbar 20. That is, in this embodiment, by joining the wires 12 of the electric wire 10 in the missing portions of the first thin-walled region 22A and the second thin-walled region 22B, it is possible to prevent the wires 12 from protruding outward in the thickness direction of the bus bar 20. Consequently, it is possible to reduce the thickness of the joint portion between the bus bar 20 and the electric wire 10.

[0017] FIG. 4A shows a joint structure employing the joint structure between a busbar and an electric wire according to the present embodiment, and FIG. 4B shows a joint structure between a busbar and an electric wire according to a related art. In FIG. 4B, components that are substantially the same as those in the joint structure between a busbar and an electric wire according to the present embodiment are denoted by the same reference numerals. In the structure shown in FIG. 4B, unlike the joint structure of the present embodiment shown in FIG. 4A, the first thin-walled region 22A and the second thin-walled region 22B are not formed in the joint portion 22 of the busbar 20, and the joint portion 22 of the busbar 20 is flush overall. In the joint structure shown in FIG. 4B, the wires 12 of the electric wire 10 are placed on and abut the joint portion 22 of the busbar 20, protruding outward in the thickness direction of the busbar 20. In contrast, in the structure employing the joint structure between a busbar and an electric wire according to the present embodiment, as shown in FIG. 4B, the wires 12 do not protrude outward in the thickness direction of the busbar 20. Comparing FIG. 4A and FIG. 4B, it is clear that the joint structure of this embodiment shown in FIG. 4A can reduce the thickness of the joint portion.

[0018] In this embodiment, the thicknesses of the first thin-walled region 22A and the second thin-walled region 22B at the joint 22 are set so that the wires 12 of the electric wire 10 do not protrude outward in the thickness direction of the busbar 20 when the wires 12 are joined to the joint 22 of the busbar 20. For example, the thicknesses of the first thin-walled region 22A and the second thin-walled region 22B may be set to be half or less of the thickness of the busbar 20 other than the first thin-walled region 22A and the second thin-walled region 22B. However, it is preferable that the thicknesses of the first thin-walled region 22A and the second thin-walled region 22B be set to a level that prevents the busbar 20 from deforming or breaking when an external force is applied when the busbar 20 and the electric wire 10 are joined.

[0019] After the joint portion 22 of the bus bar 20 and the conductor wires (plurality of wires 12) of the electric wire 10 are brought into contact as described above, they can be fixed by being joined. The joining of the joint portion 22 of the bus bar 20 and the conductor wires of the electric wire 10 can be performed by, for example, ultrasonic welding, laser welding, resistance heating welding, or the like.

[0020] The first thin-walled region 22A and the second thin-walled region 22B are preferably positioned symmetrically with respect to the central axis extending in the longitudinal direction of the busbar 20. By forming them in this manner, it is possible to reduce uneven distribution or dispersion of stress occurring in the joint 22 that is thinned by forming the first thin-walled region 22A and the second thin-walled region 22B.

[0021] In this embodiment, the first thin-walled region 22A and the second thin-walled region 22B are preferably formed so that, in a plan view of the busbar 20, they partially overlap along the central axis direction extending in the longitudinal direction of the busbar 20 (see FIG. 2C ). When the first thin-walled region 22A and the second thin-walled region 22B partially overlap as described above, the space into which the wires 12 of the electric wire 10 are inserted is enlarged, facilitating joining of the wires 12 to the joint portion 22. In this case, if the thicknesses of the first thin-walled region 22A and the second thin-walled region 22B are less than half the thickness of the busbar 20 other than the first thin-walled region 22A and the second thin-walled region 22B, a slit-like space is formed between the first thin-walled region 22A and the second thin-walled region 22B. This further increases the space into which the wires 12 of the electric wire 10 are inserted. This further facilitates joining of the wires 12 to the joint portion 22.

[0022] In this embodiment, the thickness of the joint portion 22 of the busbar 20 is preferably chamfered so as to gradually decrease toward the tip of the busbar 20. That is, both the first thin-walled region 22A and the second thin-walled region 22B of the joint portion 22 of the busbar 20 are preferably chamfered so as to gradually decrease toward the tip of the busbar 20, as shown in Fig. 2B . By chamfering in this manner, when the wires 12 of the electric wire 10 are inserted into the joint portion 22 of the busbar 20, the wires 12 are guided by the joint portion 22, making it easier to join the electric wire 10 to the busbar 20.

[0023] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment. [Explanation of symbols]

[0024] 1. Joint structure between busbar and electric wire 10 Electric wire 12 wire 14 Covering part 20 Busbar 22 Joint 22A 1st thin area 22B 2nd thin area 24 Insulating resin 26 Terminal section

Claims

1. a flat-shaped electric wire having a plurality of wires joined to a joint portion at one end of the bus bar, the joint portion of the bus bar includes a first thin-walled region and a second thin-walled region adjacent to the first thin-walled region in a width direction of the bus bar, the first thin-walled region is formed by removing a portion of a surface of the bus bar on a bottom side, and the second thin-walled region is formed by removing a portion of a surface of the bus bar on a top side, a joint structure between a busbar and an electric wire, wherein at the joint portion of the busbar, the plurality of wires of the electric wire are joined to a bottom side of the first thin-walled region and to an upper side of the second thin-walled region.

2. The joining structure between a bus bar and an electric wire according to claim 1 , wherein the first thin-walled region and the second thin-walled region are positioned symmetrically with respect to a central axis extending in a longitudinal direction of the bus bar.

3. 3. The joining structure between a busbar and an electric wire according to claim 1, wherein the first thin-walled region and the second thin-walled region are formed so as to partially overlap each other along a central axis direction extending in a longitudinal direction of the busbar in a plan view of the busbar.

4. 3. The joining structure for connecting a bus bar and an electric wire according to claim 1, wherein the first thin-walled region and the second thin-walled region are chamfered so that the thicknesses thereof gradually decrease toward the tip of the bus bar.

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