Bus bar

Abstract

To provide a bus bar that can improve heat dissipation.SOLUTION: A bus bar 20 according to an embodiment includes a plate-shaped extension portion 23. When viewed in a cross section intersecting the extension direction of the extension portion 23, the extension portion 23 has a first main surface 41, a first side portion 43, and a first corner portion 51. The first side portion 43 faces in a different direction from the first main surface 41. The first corner portion 51 connects the first main surface 41 and the first side portion 43. The first corner portion 51 has at least one of a curved surface that is convex toward the outside of the extension portion 23 and an inclined surface that is inclined at an angle of more than 45 degrees with respect to the first main surface 41.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] For example, bus bars are used as one type of electrical connection member for vehicles, and each bus bar has a connection portion that is connected to an electrical component and a plate-like extension portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-023721 Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the usage environment, the temperature of the bus bar may easily rise.

[0005] One embodiment provides a bus bar that can improve heat dissipation. [Means for solving the problem]

[0006] In one embodiment, the busbar includes a plate-shaped extension portion. When viewed in a cross section intersecting the extension direction of the extension portion, the extension portion has a first main surface, a first side portion, and a first corner portion. The first side portion faces in a different direction from the first main surface. The first corner portion connects the first main surface and the first side portion. The first corner portion has at least one of a curved surface that is convex toward the outside of the extension portion or an inclined surface that is inclined at an angle of more than 45 degrees with respect to the first main surface. [Effects of the Invention]

[0007] According to one embodiment, the heat dissipation performance of the bus bar can be improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing an example of a vehicle including a bus bar according to a first embodiment. [Figure 2] FIG. 2 is a perspective view showing an example of a bus bar according to the first embodiment. [Figure 3] 3 is a cross-sectional view of the bus bar taken along line F3-F3 in FIG. 2. [Figure 4A] FIG. 10 is a diagram showing a simulation result for a bus bar of a comparative example. [Figure 4B] FIG. 10 is a diagram for explaining the air flow around the bus bar of the comparative example. [Figure 5A] FIG. 4 is a diagram showing a simulation result regarding the bus bar according to the first embodiment. [Figure 5B] FIG. 3 is a diagram for explaining an air flow around the bus bar according to the first embodiment. [Figure 6] FIG. 4 is a diagram showing the relationship between the radius of curvature and the cross-sectional area ratio in the first embodiment. [Figure 7] FIG. 4 is a diagram showing the relationship between the radius of curvature and the temperature rise of the bus bar in the first embodiment. [Figure 8] FIG. 4 is a cross-sectional view showing a bus bar according to a first modified example of the first embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing a bus bar according to a second modified example of the first embodiment. [Figure 10] FIG. 6 is a cross-sectional view showing a bus bar according to a second embodiment. [Figure 11] FIG. 10 is a diagram showing a simulation result regarding the bus bar of the second embodiment. [Figure 12] FIG. 10 is a cross-sectional view showing an example of an electrical connection unit according to a modified example of the second embodiment. [Figure 13] 13 is a cross-sectional view of the electrical connection unit shown in FIG. 12 taken along line F13-F13. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the following description, components having the same or similar functions will be assigned the same reference numerals. Duplicate descriptions of these components may be omitted. In this disclosure, terms are defined as follows: "Connection" is not limited to mechanical connection, but may also include electrical connection. That is, "connection" is not limited to direct connection between two elements to be connected, but may also include connection between two elements via another element interposed therebetween. "Parallel," "orthogonal," "horizontal," "circular," "right-angled," or "same" may respectively include cases where "approximately parallel," "approximately perpendicular," "approximately horizontal," "approximately circular," "approximately right-angled," or "same."

[0010] In this disclosure, the X direction, Y direction, and Z direction are defined as follows: The X direction is the extension direction of the first extension portion 23a of the bus bar 20, which will be described later. The Y direction is the width direction of the first extension portion 23a of the bus bar 20. The Z direction is the thickness direction of the first extension portion 23a of the bus bar 20. Note that the horizontal direction and the up / down / left / right directions in the following description are based on the posture of the bus bar 20 when in use (for example, when mounted on a vehicle V).

[0011] (First embodiment) <1. Busbar configuration> 1 is a diagram illustrating an example of a vehicle V including a bus bar 20 according to the first embodiment. The vehicle V is, for example, an electric vehicle such as an EV (Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a PHEV (Plug-in Hybrid Electric Vehicle).

[0012] The vehicle V has, for example, a motor 11, an inverter 12, a high-voltage battery 13, a charging port 14, and a plurality of bus bars 20 (for example, a first bus bar 20A and a second bus bar 20B). Each of the motor 11, the inverter 12, the high-voltage battery 13, and the charging port 14 is an example of an "electrical component."

[0013] The bus bar 20 is an electrical connection member that electrically connects multiple electrical components. In the example shown in FIG. 1, the first bus bar 20A connects the inverter 12 and the high-voltage battery 13. The second bus bar 20B connects the charging port 14 and the high-voltage battery 13. Note that the connection targets of the bus bar 20 are not limited to the above example. The bus bar 20 can also be applied to various electrical components other than those in the above example.

[0014] 2 is a perspective view showing an example of a busbar 20. The busbar 20 has, for example, a first connection portion 21, a second connection portion 22, and an extension portion 23. In this embodiment, the first connection portion 21, the second connection portion 22, and the extension portion 23 are each plate-shaped. That is, the first connection portion 21, the second connection portion 22, and the extension portion 23 each have a flat rectangular cross-sectional shape.

[0015] (First connection part) The first connection portion 21 is a portion that is connected to a first electric component that is a connection target. The first connection portion 21 is provided at one end of the bus bar 20. The first connection portion 21 has an insertion hole 21h through which a fastening member (e.g., a screw) (not shown) is passed.

[0016] (Second connection part) Second connection portion 22 is a portion that is connected to a second electric component that is another connection target. Second connection portion 22 is provided at the other end of bus bar 20. Second connection portion 22 has an insertion hole 22h through which a fastening member (e.g., a screw) (not shown) is passed.

[0017] (extension part) The extension portion 23 is provided between the first connection portion 21 and the second connection portion 22. The extension portion 23 has, for example, a first extension portion 23a, a second extension portion 23b, and a third extension portion 23c.

[0018] The first extending portion 23a extends, for example, in the X direction along the horizontal direction. Similarly, the second extending portion 23b extends, for example, in the X direction along the horizontal direction. The third extending portion 23c is provided between the first extending portion 23a and the second extending portion 23b and connects the first extending portion 23a and the second extending portion 23b. The third extending portion 23c extends, for example, in a direction intersecting the horizontal direction. Note that the shape of the extending portion 23 is not limited to the above example. For example, the extending portion 23 may have only the first extending portion 23a and extend linearly, or may be bent in a more complex manner.

[0019] 3 is a cross-sectional view of busbar 20 taken along line F3-F3 in FIG. 2. Busbar 20 of this embodiment is a busbar with a shielded structure (hereinafter referred to as a "shielded busbar"). Note that the term "shielded busbar" used in this disclosure is used for the sake of convenience and does not limit the scope of the invention to a specific structure. Busbar 20 includes, for example, a conductor 31, an insulating coating 32, and a shielding layer 33.

[0020] (conductor) The conductor 31 forms an electric path through which a current flows in the bus bar 20. The conductor 31 is made of, for example, a metal. The conductor 31 is, for example, a member having a flat rectangular cross section.

[0021] (insulating coating) The insulating coating 32 is an insulating member that covers the outer periphery of the conductor 31. The insulating coating 32 is made of, for example, a synthetic resin. For example, when the conductor 31 has a flat rectangular cross-sectional shape, the insulating coating 32 covers the outer periphery of the conductor 31 so as to surround the entire periphery of the cross-sectional shape. The insulating coating 32 has a film thickness t1. The insulating coating 32 is provided on the extension portion 23 of the busbar 10. On the other hand, the first connection portion 21 and the second connection portion 22 of the busbar 20 are not covered by the insulating coating 32 and are exposed to the outside of the busbar 20.

[0022] (shield layer) The shield layer 33 is a shield portion that covers the outer periphery of the insulating coating 32. The shield layer 33 is, for example, a shield portion for noise reduction. The shield layer 33 is, for example, a metal film (metal layer), but is not limited to this. The shield layer 33 may have a braided or mesh structure, etc. In this embodiment, the shield layer 33 is integrated with the conductor 31 and the insulating coating 32. For example, in the case of the conductor 31 having a flat rectangular cross-sectional shape, the shield layer 33 covers the outer periphery of the insulating coating 32 so as to surround the entire periphery of the cross-sectional shape. The shield layer 33 has a film thickness t2. The shield layer 33 is provided on the extension portion 23 of the busbar 10. On the other hand, the first connection portion 21 and the second connection portion 22 of the busbar 20 are not covered by the shield layer 33 and are exposed to the outside of the busbar 20.

[0023] In this embodiment, the shield layer 33 forms the outer surface of the bus bar 20. The surface of the shield layer 33 forms a first main surface 41, a second main surface 42, a first side surface 43, and a second side surface 44, which will be described later. The surface of the shield layer 33 forms the surfaces of first to fourth corners 51 to 54, which will be described later. The surface of the shield layer 33 forms a curved surface RA, which will be described later.

[0024] Note that busbar 20 is not limited to the shielded busbar described above. Busbar 20 may be formed, for example, by conductor 31 and insulating coating 32 without having shield layer 33. In this case, first main surface 41, second main surface 42, first side surface 43, second side surface 44, and first to fourth corners 51 to 54, which will be described later, are formed by the surface of insulating coating 32. Alternatively, busbar 20 may be formed, for example, by conductor 31 alone without having insulating coating 32 and shield layer 33. In this case, first main surface 41, second main surface 42, first side surface 43, second side surface 44, and first to fourth corners 51 to 54, which will be described later, are formed by the surface of conductor 31.

[0025] <2. Shape of busbar corners> Next, the shape of the corners of the bus bar 20 will be described. As shown in Figure 3, when viewed in a cross section intersecting the extension direction of extension portion 23 (e.g., first extension portion 23a), extension portion 23 has, for example, a first main surface 41, a second main surface 42, a first side surface 43, and a second side surface 44.

[0026] (First main surface) The first main surface 41 is located at one end of the busbar 20 in the Z direction. The first main surface 41 faces the one side in the Z direction. The first main surface 41 is a plane extending along the X direction and the Y direction. The first main surface 41 is disposed, for example, along the horizontal direction. The first main surface 41 forms, for example, the top surface of the busbar 20. The first main surface 41 is larger than a first side surface 43 and a second side surface 44, which will be described later.

[0027] (Second main surface) The second main surface 42 is located on the opposite side of the busbar 20 in the Z direction from the first main surface 41. The second main surface 42 is located at the end of the busbar 20 on the other side in the Z direction. The second main surface 42 faces the other side in the Z direction. The second main surface 42 extends parallel to the first main surface 41. The second main surface 42 is, for example, a plane extending along the X direction and the Y direction. The second main surface 42 is, for example, arranged along the horizontal direction. The second main surface 42 forms the lower surface of the busbar 20. The second main surface 42 is larger than a first side surface 43 and a second side surface 44, which will be described later.

[0028] (1st aspect) The first side surface 43 is located at one end of the busbar 20 in the Y direction. The first side surface 43 faces a different direction from the first main surface 41. The first main surface 41 faces, for example, the one side in the Y direction. The first side surface 43 is, for example, a plane extending along the X and Y directions. The first side surface 43 is disposed, for example, along the vertical direction. The first side surface 43 is an example of a "first side portion." Note that the "first side portion" is not limited to having a planar side surface, and does not necessarily have to have a planar side surface. For example, if the first side surface 43 does not exist and a first corner portion 51 and a second corner portion 52 (described later) are directly adjacent to each other, the boundary between the first corner portion 51 and the second corner portion 52 is an example of a "first side portion." Therefore, in the following description, the "first side surface 43" may be read as the "first side portion."

[0029] (Second side) The second side surface 44 is located on the opposite side of the busbar 20 in the Y direction from the first side surface 43. The second side surface 44 is located at the end of the busbar 20 on the other side in the Y direction. The second side surface 44 faces in a direction different from the first main surface 41. The first main surface 41 faces, for example, the other side in the Y direction. The second side surface 44 is, for example, a plane extending along the X direction and the Y direction. The second side surface 44 is, for example, disposed along the vertical direction. The second side surface 44 is an example of a "second side portion." Note that the "second side portion" is not limited to having a planar side surface, and does not necessarily have to have a planar side surface. For example, if the second side surface 44 does not exist and a third corner portion 53 and a fourth corner portion 54 (described later) are directly adjacent to each other, the boundary between the third corner portion 53 and the fourth corner portion 54 is an example of a "second side portion."

[0030] (corner) As shown in Figure 3, when viewed in a cross section intersecting the extension direction of extension portion 23 (e.g., first extension portion 23a), extension portion 23 has, for example, a first corner 51, a second corner 52, a third corner 53, and a fourth corner 54.

[0031] The first corner 51 is provided between the first main surface 41 and the first side surface 43 and connects the first main surface 41 and the first side surface 43. The second corner 52 is provided between the second main surface 42 and the first side surface 43 and connects the second main surface 42 and the first side surface 43. The third corner 53 is provided between the first main surface 41 and the second side surface 44 and connects the first main surface 41 and the second side surface 44. The fourth corner 54 is provided between the second main surface 42 and the second side surface 44 and connects the second main surface 42 and the second side surface 44.

[0032] In this embodiment, each of the first corner 51, the second corner 52, the third corner 53, and the fourth corner 54 has a curved surface RA that is convex toward the outside of the extension portion 23. In this embodiment, the curved surface RA is an arc-shaped curved surface that is one-fourth of a perfect circle. In this case, the radius of curvature R1 of the curved surface RA corresponds to an example of the "minimum radius of curvature of a curved surface." Therefore, in the following description, the "radius of curvature R1" may be read as the "minimum radius of curvature." In this disclosure, the "minimum radius of curvature" is the radius of curvature of the portion on the curved surface where the radius of curvature is smallest.

[0033] In this embodiment, the radius of curvature R1 is 1 mm or more. For example, the radius of curvature R1 is 1 mm or more and 5 mm or less. From another perspective, assuming an imaginary line V1 extending from the first main surface 41 in the Y direction, the first corner 51 and the third corner 53 have a curved surface RA over a range of a distance L1 from the imaginary line V1 in the Z direction. The distance L1 is 1 mm or more. For example, the distance L1 is 1 mm or more and 5 mm or less. Similarly, assuming an imaginary line V2 extending from the second main surface 42 in the Y direction, the second corner 52 and the fourth corner 54 have a curved surface RA over a range of a distance L2 from the imaginary line V2 in the Z direction. The distance L2 is 1 mm or more. For example, the distance L2 is 1 mm or more and 5 mm or less.

[0034] From another perspective, the radius of curvature R1 is, for example, larger than the film thickness t1 of the insulating coating 32. The radius of curvature R1 is, for example, larger than the film thickness t2 of the shield layer 33. Note that the embodiment is not limited to the configuration having the above-described dimensions or dimensional relationships.

[0035] <3. Outer shape of conductor> Next, the outer shape of the conductor 31 will be described. As shown in FIG. 3, when viewed in a cross section intersecting the extension direction of extension portion 23 (e.g., first extension portion 23a), conductor 31 has, for example, a first conductor main surface 61, a second conductor main surface 62, a first conductor side surface 63, and a second conductor side surface 64.

[0036] (First conductor main surface) The first conductor principal surface 61 is located at one end of the conductor 31 in the Z direction. The first conductor principal surface 61 is parallel to the first principal surface 41. The first conductor principal surface 61 is larger than a first conductor side surface 63 and a second conductor side surface 64, which will be described later.

[0037] (Second conductor main surface) The second conductor principal surface 62 is located on the opposite side of the conductor 31 in the Z direction from the first conductor principal surface 61. The second conductor principal surface 62 is located at the end of the conductor 31 on the other side in the Z direction. The second conductor principal surface 62 is parallel to the second principal surface 42. The second conductor principal surface 62 is larger than the first conductor side surface 63 and the second conductor side surface 64, which will be described later.

[0038] (First conductor side) The first conductor side surface 63 is located at one end of the conductor 31 in the Y direction. The first conductor side surface 63 is parallel to the first side surface 43. The first conductor side surface 63 is an example of a "first conductor side portion." Note that the "first conductor side portion" is not limited to having a planar side surface, and does not necessarily have to have a planar side surface. For example, if the first conductor side surface 63 does not exist and a first conductor corner portion 71 and a second conductor corner portion 72 (described later) are directly adjacent to each other, the boundary between the first conductor corner portion 71 and the second conductor corner portion 72 is an example of a "first conductor side portion." Therefore, in the following description, the "first conductor side surface 63" may be read as the "first conductor side portion."

[0039] (Second conductor side) The second conductor side surface 64 is located on the opposite side of the conductor 31 in the Y direction from the first conductor side surface 63. The second conductor side surface 64 is parallel to the second side surface 44. The second conductor side surface 64 is an example of a "second conductor side portion." Note that the "second conductor side portion" is not limited to having a planar side surface, and does not necessarily have to have a planar side surface. For example, if the second conductor side surface 64 does not exist and a third conductor corner portion 73 and a fourth conductor corner portion 74 (described later) are directly adjacent to each other, the boundary between the third conductor corner portion 73 and the fourth conductor corner portion 74 is an example of a "second conductor side portion." Therefore, in the following description, "second conductor side surface 64" may be read as "second conductor side portion."

[0040] (corner) As shown in FIG. 3, when viewed in a cross section intersecting the extension direction of extension portion 23 (e.g., first extension portion 23a), conductor 31 has, for example, a first conductor corner 71, a second conductor corner 72, a third conductor corner 73, and a fourth conductor corner 74.

[0041] The first conductor corner portion 71 is located on the inner circumferential side of the first corner portion 51. The first conductor corner portion 71 is provided between the first conductor principal surface 61 and the first conductor side surface 63, and connects the first conductor principal surface 61 and the first conductor side surface 63. The second conductor corner portion 72 is located on the inner circumferential side of the second corner portion 52. The second conductor corner portion 72 is provided between the second conductor principal surface 62 and the first conductor side surface 63, and connects the second conductor principal surface 62 and the first conductor side surface 63.

[0042] The third conductor corner portion 73 is located on the inner circumferential side of the third corner portion 53. The third conductor corner portion 73 is provided between the first conductor principal surface 61 and the second conductor side surface 64, and connects the first conductor principal surface 61 and the second conductor side surface 64. The fourth conductor corner portion 74 is located on the inner circumferential side of the fourth corner portion 54. The fourth conductor corner portion 74 is provided between the second conductor principal surface 62 and the second conductor side surface 64, and connects the second conductor principal surface 62 and the second conductor side surface 64.

[0043] In this embodiment, each of the first conductor corner 71, the second conductor corner 72, the third conductor corner 73, and the fourth conductor corner 74 has a conductor curved surface RB that is convex toward the outside of the extension portion 23. In this embodiment, the conductor curved surface RB is a curved surface having an arc-shaped surface that is one-fourth of a perfect circle. In this case, the radius of curvature R11 of the conductor curved surface RB corresponds to an example of the "minimum radius of curvature of a curved surface." Therefore, in the following description, the "radius of curvature R11" may be interpreted as the "minimum radius of curvature." The radius of curvature R11 is, for example, larger than the film thickness t1 of the insulating coating 32. The radius of curvature R11 is, for example, larger than the film thickness t2 of the shield layer 33. Note that the embodiment is not limited to the configuration having the above-described dimensions or dimensional relationships.

[0044] <3. Effect> Next, we will explain the function of busbar 20. First, we will explain the function of busbar 20X of the comparative example. First to fourth corners 51 to 54 of busbar 20X of the comparative example do not have a curved surface RA, but are corners bent at right angles.

[0045] 4A is a diagram showing the results of a simulation of the busbar 20X of the comparative example. This diagram shows the airflow and air temperature around the busbar 20X when the busbar 20X reaches a high temperature. Research by the present inventors has revealed that the airflow around the busbar 20X of the comparative example is less stable, which can reduce the heat dissipation efficiency.

[0046] 4B is a diagram illustrating the airflow around busbar 20X of the comparative example. As shown in FIG. 4B, when busbar 20X is energized, the center of busbar 20X heats up due to heat generated by electrical equipment connected to busbar 20X and / or heat generated by busbar 20X itself (Joule heat). The heat in the center of busbar 20X then moves to the surface of busbar 20X (see arrow H in the figure). This warms the air around busbar 20X.

[0047] In this case, the air near the first side surface 43 is heated by the first side surface 43 and becomes an upward flow A that rises along the first side surface 43. In the comparative example, because the first corner 51 is a right-angled corner, the upward flow A is less likely to move smoothly above the first main surface 41 after passing beside the first corner 51 and is more likely to continue rising. As a result, in a portion of the region above the first main surface 41 (region S in the figure), the air density decreases, and a vortex Aa is more likely to occur, in which part of the upward flow A flows backward and descends. When the vortex Aa occurs, the air near the first main surface 41 is less likely to rise smoothly. As a result, the heat dissipation efficiency of the first main surface 41 decreases. This can be confirmed, for example, by the occurrence of a localized high-temperature area in part of the first main surface 41 of the busbar 20X (see FIG. 4A).

[0048] Next, the operation of the bus bar 20 of this embodiment will be described. Fig. 5A is a diagram showing the results of a simulation of the busbar 20 of this embodiment. Fig. 5A shows the surrounding air flow and air temperature when the busbar 20 becomes hot. Research by the present inventors has confirmed that the configuration of this embodiment makes it easier for the air flow around the busbar 20 to stabilize, improving heat dissipation efficiency.

[0049] 5B is a diagram illustrating the airflow around the busbar 20 of this embodiment. As shown in FIG. 5B, when the busbar 20 is energized, the center of the busbar 20 heats up due to heat generated by the electrical equipment connected to the busbar 20 and / or heat generated by the busbar 20 itself (Joule heat). The heat in the center of the busbar 20 then moves to the surface of the busbar 20 (see arrow H in the figure). This warms the air around the busbar 20.

[0050] In this case, the air near the first side surface 43 is heated by the first side surface 43 and becomes an upward flow A that rises along the first side surface 43. At this time, in the busbar 20 of this embodiment, because the first corner 51 has a curved surface RA, part of the upward flow A tends to move smoothly above the first main surface 41 along the curved surface RA of the first corner 51. As a result, a region where the air density is reduced is less likely to occur in a portion above the first main surface 41. Therefore, the above-mentioned vortex Aa is less likely to occur. When the vortex Aa is less likely to occur, the air near the first main surface 41 tends to rise smoothly, improving the heat dissipation efficiency of the first main surface 41. This can be confirmed, for example, by the fact that a local high-temperature portion is less likely to occur in a portion of the first main surface 41 of the busbar 20 (see FIG. 5A ).

[0051] <4. Effect of curved surface size> Next, the influence of the size of the curved surface RA will be described. 6 is a diagram showing the relationship between the radius of curvature of the curved surface RA and the cross-sectional area ratio. In the present disclosure, the "cross-sectional area ratio" is an index obtained by dividing the cross-sectional area of ​​the extension portion 23 when the first to fourth corners 51 to 54 have curved surfaces RA by the cross-sectional area of ​​the extension portion 23 when the first to fourth corners 51 to 54 are right angles. As shown in FIG. 6, for example, when the radius of curvature of the curved surface RA is 1 mm or more, the cross-sectional area of ​​the extension portion 23 is significantly reduced.

[0052] FIG. 7 is a diagram showing the relationship between the radius of curvature of the curved surface RA and the temperature rise of the busbar 20. As shown in FIG. 7, when the radius of curvature is 5 mm or less, the temperature rise is suppressed compared to when the first to fourth corners 51 to 54 are right angles. On the other hand, when the radius of curvature is greater than 5 mm, the temperature rise may be less suppressed compared to when the first to fourth corners 51 to 54 are right angles. Therefore, based on the results of FIGS. 6 and 7, it is preferable that the radius of curvature of the first corner 51 of the busbar 20 is, for example, 1 mm or more and 5 mm or less. Note that these dimensions do not limit the scope of this embodiment.

[0053] <5. Advantages> In recent years, electric vehicles have become increasingly heavy current drivers. To accommodate these larger currents, it is necessary to increase the cross-sectional area of ​​the busbar. However, increasing the cross-sectional area of ​​the busbar may reduce the vehicle's mountability due to space constraints. In addition, increasing the cross-sectional area of ​​the busbar may increase the amount of material used, resulting in increased costs.

[0054] Furthermore, a shielded busbar 20 may be used for the purpose of noise reduction, etc. In a shielded busbar, if the surface of the shield layer 33 is untreated (for example, if it has not been anodized, polished, or oxidized), the reflectivity may be low and efficient heat dissipation by radiation may be difficult to expect. In this case, the temperature of the shielded busbar may be more likely to rise than in a busbar in which the conductor 31 has been exposed after undergoing the above-mentioned surface treatment.

[0055] On the other hand, in this embodiment, the busbar 20 includes a plate-shaped extension portion 23. When viewed in a cross section intersecting the extension direction of the extension portion 23, the extension portion 23 has a first main surface 41, a first side surface 43 (first lateral portion) facing in a different direction from the first main surface 41, and a first corner portion 51 connecting the first main surface 41 and the first side surface 43. The first corner portion 51 has a curved surface RA that is convex toward the outside of the extension portion 23. With this configuration, as described above, the air flow around the busbar 20 is more likely to be stable, thereby improving the heat dissipation efficiency of the first main surface 41. This improves the heat dissipation performance of the busbar 20.

[0056] Furthermore, when the first corner portion 51 has a curved surface RA, the amount of material used for the busbar 20 may be reduced compared to when the first corner portion 51 is a right angle. This may result in a reduction in the cost of the busbar 20. Furthermore, when the first corner portion 51 has a curved surface RA, heat dissipation is improved, which may result in a reduction in the cross-sectional area of ​​the busbar 20. Reducing the cross-sectional area of ​​the busbar 20 may improve the mountability on the vehicle V. Furthermore, even in the case of a shielded busbar, the first corner portion 51 having a curved surface RA improves heat dissipation. Therefore, even when a shielded busbar 20 is used, it may be possible to suppress an increase in temperature of the busbar 20.

[0057] In this embodiment, the radius of curvature (minimum radius of curvature) R1 of the curved surface RA of the first corner portion 51 is 1 mm or more. With this configuration, it is easier to improve the heat dissipation performance of the bus bar 20 while reducing the amount of material used for the bus bar 20.

[0058] In this embodiment, the radius of curvature (minimum radius of curvature) R1 of the curved surface RA of the first corner portion 51 is larger than the thickness t1 of the insulating coating 32. With this configuration, it is easier to improve the heat dissipation of the bus bar 20 compared to when the radius of curvature R1 of the curved surface RA is smaller than the thickness t1 of the insulating coating 32.

[0059] In this embodiment, the surface of the first corner portion 51 is formed by a part of the surface of the shield layer 33. With this configuration, even when the bus bar 20 is a shielded bus bar, the first corner portion 51 has a curved surface RA, which improves the heat dissipation of the bus bar 20.

[0060] In this embodiment, the radius of curvature (minimum radius of curvature) R1 of the curved surface RA of the first corner portion 51 is larger than the thickness t2 of the shield layer 33. With this configuration, it is easier to improve the heat dissipation of the bus bar 20 compared to when the radius of curvature R1 of the curved surface RA is smaller than the thickness t2 of the shield layer 33.

[0061] In this embodiment, the conductor 31 has a first conductor principal surface 61 parallel to the first principal surface 41, a first conductor side surface 63 parallel to the first side surface 43, and a first conductor corner 71 connecting the first conductor principal surface 61 and the first conductor side surface 63. The first conductor corner 71 has a conductor curved surface RB that is located on the inner periphery of the curved surface RA of the first corner 51 and that is convex toward the outside of the extension portion 23. With this configuration, it is easier to set a larger radius of curvature for the curved surface RA of the first corner 51 than when the first conductor corner 71 is a right angle. This makes it easier to improve the heat dissipation of the busbar 20.

[0062] (Variation) Next, several modified examples of the bus bar 20 will be described. Note that the configuration of each modified example other than that described below is the same as that of the first embodiment.

[0063] (First Modification) FIG. 8 is a cross-sectional view showing a busbar 20 according to a first modified example of the first embodiment. In the first modified example, the first to fourth corners 51 to 64 have curved surfaces RC. The curved surfaces RC are arc-shaped surfaces that correspond to portions of an ellipse. In this case, the radius of curvature of the curved surfaces RC varies at each position on the surface of the curved surfaces RC. In this modified example, the minimum radius of curvature R2 of the curved surfaces RC is 1 mm or more. For example, the minimum radius of curvature R2 of the curved surfaces RC is 1 mm or more and 5 mm or less.

[0064] From another perspective, assuming an imaginary line V1 extending from the first main surface 41 in the Y direction, the first corner 51 and the third corner 53 have a curved surface RC over a range of distance L1 from the imaginary line V1 in the Z direction. Distance L1 is 1 mm or more. For example, distance L1 is 1 mm or more and 5 mm or less. Similarly, assuming an imaginary line V2 extending from the second main surface 42 in the Y direction, the second corner 52 and the fourth corner 54 have a curved surface RC over a range of distance L2 from the imaginary line V2 in the Z direction. Distance L2 is 1 mm or more. For example, distance L2 is 1 mm or more and 5 mm or less.

[0065] In this modification, assuming an imaginary line V3 extending from the first side surface 43 in the Z direction, the first corner 51 and the second corner 52 have a curved surface RC over a range of a distance L3 from the imaginary line V3 in the Y direction. The distance L3 is, for example, shorter than the distance L1. The distance L3 is, for example, shorter than the distance L2.

[0066] From another perspective, the minimum curvature radius R2 is, for example, larger than the film thickness t1 of the insulating coating 32. The minimum curvature radius R2 is, for example, larger than the film thickness t2 of the shield layer 33. Note that the embodiment is not limited to the configuration having the above-described dimensions or dimensional relationships.

[0067] In this modification, the first to fourth conductor corners 71 to 74 have conductor curved surfaces RD located on the inner periphery of the curved surface RC. The conductor curved surface RD is, for example, an arc-shaped curved surface equivalent to a part of an ellipse. The conductor curved surface RD is, for example, a curved surface similar in shape to the curved surface RC.

[0068] Even with this configuration, the first corner portion 51 has a curved surface RC, which makes it difficult for a vortex Aa to be generated above the first main surface 41, thereby improving the heat dissipation efficiency of the first main surface 41. This improves the heat dissipation performance of the bus bar 20.

[0069] (Second Modification) 9 is a cross-sectional view showing a busbar 20 according to a second modified example of the first embodiment. In the second modified example, the first to fourth corners 51 to 54 have inclined surfaces CA instead of curved surfaces RA. For example, the first corner 51 and the third corner 53 are inclined surfaces inclined at an angle α greater than 45 degrees relative to the first main surface 41 (for example, 60 degrees relative to the first main surface 41). Similarly, the second corner 52 and the fourth corner 54 are inclined surfaces inclined at an angle α greater than 45 degrees relative to the second main surface 42 (for example, 60 degrees relative to the second main surface 42).

[0070] In this modification, the first to fourth conductor corners 71 to 74 have an inclined surface CB located on the inner peripheral side of the inclined surface CA. The first conductor corner 71 and the third conductor corner 73 are inclined surfaces inclined at an angle α greater than 45 degrees relative to the first conductor principal surface 61 (for example, 60 degrees relative to the first conductor principal surface 61). Similarly, the second conductor corner 72 and the fourth conductor corner 74 are inclined surfaces inclined at an angle α greater than 45 degrees relative to the second conductor principal surface 62 (for example, 60 degrees relative to the second conductor principal surface 62).

[0071] Even with this configuration, the first corner portion 51 has the inclined surface CA, which makes it difficult for a vortex Aa to be generated above the first main surface 41, thereby improving the heat dissipation efficiency of the first main surface 41. For example, the inventors have found through experiments that when the inclined surface CA is inclined at an angle of more than 45 degrees with respect to the first main surface 41, the heat dissipation efficiency of the first main surface 41 is improved compared to when the inclined surface CA is inclined at an angle of 45 degrees or less with respect to the first main surface 41.

[0072] (Second embodiment) Next, a second embodiment will be described. The second embodiment differs from the first embodiment in that the shapes of the upper and lower surfaces of the extension portion 23 of the bus bar 20 are asymmetrical. Note that the configuration other than that described below is the same as that of the first embodiment.

[0073] 10 is a cross-sectional view showing a busbar 20 according to the second embodiment. In this embodiment, the first corner 51 and the third corner 53 have curved surfaces RA, similar to the first embodiment. On the other hand, the second corner 52 and the fourth corner 54 are right-angled. That is, each of the second corner 52 and the fourth corner 54 has a bent surface TA that is bent at a right angle.

[0074] In this embodiment, the first conductor corner 71 and the third conductor corner 73 have a conductor curved surface RB, similar to the first embodiment. On the other hand, the second conductor corner 72 and the fourth conductor corner 74 are right-angled. That is, the second conductor corner 72 and the fourth conductor corner 74 each have a curved surface TB that is bent at a right angle.

[0075] 11 is a diagram showing the results of a simulation of the busbar 20 of the second embodiment. As shown in FIG. 11, when the first corner 51 has a curved surface RA, even if the second corner 52 does not have a curved surface RA, vortices Aa are less likely to be generated above the first main surface 41, thereby improving the heat dissipation efficiency of the first main surface 41. This improves the heat dissipation performance of the busbar 20.

[0076] The second embodiment is not limited to the above example. For example, the second corner 52 and the fourth corner 54 may have a curved surface RA smaller than the curved surface RA of the first corner 51 and the third corner 53. That is, the radius of curvature R1 of the curved surface RA of the second corner 52 and the fourth corner 54 may be smaller than the radius of curvature R1 of the curved surface RA of the first corner 51 and the third corner 53. Furthermore, the second corner 52 and the fourth corner 54 may have a curved surface RC smaller than the curved surface RC of the first corner 51 and the third corner 53. That is, the minimum radius of curvature R1 of the curved surface RC of the second corner 52 and the fourth corner 54 may be smaller than the minimum radius of curvature R1 of the curved surface RC of the first corner 51 and the third corner 53. The second corner portion 52 and the fourth corner portion 54 may have an inclined surface CA that is smaller than the inclined surface CA of the first corner portion 51 and the third corner portion 53 .

[0077] (Variation) Next, a modified bus bar 20 will be described. Note that the configuration of this modified bus bar 20 is the same as that of the second embodiment except for the configuration described below.

[0078] 12 is a diagram illustrating an example of an electrical connection unit 100 including a bus bar 20 according to the second embodiment. The electrical connection unit 100 is an electrical connection body known as an electrical connection box or a junction box. The electrical connection unit 100 includes, for example, a housing 101, a first electronic component 102, a second electronic component 103, a heat transfer member 104, and the bus bar 20.

[0079] The housing 101 has a base member 101a and a cover member 101b. The base member 101a is made of, for example, synthetic resin and has insulating properties. The base member 101a is an example of a "first housing member." The cover member 101b is made of, for example, synthetic resin and has insulating properties. The cover member 101b is an example of a "second housing member." In this modification, the housing 101 is formed by combining the base member 101a and the cover member 101b. The first electronic component 102, the second electronic component 103, the heat transfer member 104, and the bus bar 20 are housed in the housing 101.

[0080] The first electronic component 102 and the second electronic component 103 are electronic components used, for example, for switching the current state or for protection. The first electronic component 102 and the second electronic component 103 are, for example, but not limited to, connectors, fuses, relays (e.g., mechanical relays or semiconductor relays), capacitors, branching components, electronic control units, or electronic component units formed by unitizing two or more of these. The first connection portion 21 of the bus bar 20 is connected to the first electronic component 102 by a fastening member FS. The second connection portion 22 of the bus bar 20 is connected to the second electronic component 103 by a fastening member FS. In this way, the bus bar 20 electrically connects the first electronic component 102 and the second electronic component 103.

[0081] Heat transfer member 104 is disposed between a portion of extension 23 of bus bar 20 and base member 101a. Heat transfer member 104 is a resin or metal member with excellent thermal conductivity. Heat transfer member 104 transfers some of the heat held by bus bar 20 to base member 101a. As a result, some of the heat held by bus bar 20 is dissipated from base member 101a to the outside of electrical connection unit 100.

[0082] Fig. 13 is a cross-sectional view of the electrical connection unit 100 taken along line F13-F13 in Fig. 12. In this modification, the bus bar 20 does not have the insulating coating 32 or the shielding layer 33. In this modification, the conductor 31 is exposed inside the housing 101. The surface of the conductor 31 forms a first main surface 41, a second main surface 42, a first side surface 43, and a second side surface 44. The surface of the conductor 31 also forms first to fourth corners 51 to 54.

[0083] In this modification, the first corner 51 and the third corner 53 have curved surfaces RA. On the other hand, the second corner 52 and the fourth corner 54 are right angles. That is, the second corner 52 and the fourth corner 54 each have a bent surface TA bent at a right angle. In this modification, the heat transfer member 104 is in contact with the second main surface 42, the second corner 52, and the fourth corner 54.

[0084] With this configuration, because the first corner 51 has a curved surface RA, vortices Aa are less likely to be generated above the first main surface 41, improving the heat dissipation efficiency of the first main surface 41. Furthermore, if the second corner 52 is a right angle and is in contact with the heat transfer member 104, the contact area between the bus bar 20 and the heat transfer member 104 can be increased, thereby further improving the heat dissipation performance of the bus bar 20. Note that the bus bar 20 may have an insulating coating 32, or may have an insulating coating 32 and a shield layer 33, as in the first embodiment.

[0085] Several embodiments and modifications have been described above. However, the embodiments and modifications are not limited to the examples described above. For example, two or more of the above-described embodiments or modifications may be combined with each other. Each of the first to fourth corners 51 to 54 is not limited to having only one of the curved surface RA and the inclined surface CA, but may have a combination of the curved surface RA and the inclined surface CA. For example, the curved surface RA may be provided on a portion of the first corner 51, and the inclined surface CA may be provided on another portion of the first corner 51. [Explanation of symbols]

[0086] 20...busbar 21...First connection part 22...Second connection part 23,23a,23b,23c...extension part 31...conductor 32...Insulating coating 33...Shield layer 41...First main surface 42...Second main surface 43...First side surface (first side portion) 44...Second side (second side part) 51...First corner 52…Second corner 53...Third corner 54…4th corner 61...First conductor main surface 62...Second conductor main surface 63...First conductor side surface (first conductor side portion) 64...Second conductor side surface (second conductor side portion) 71...First conductor corner 72...Second conductor corner 73...Third conductor corner 74...Fourth conductor corner V...Vehicle RA,RB,RC,RD…Curved surface CA,CB…Slanted surface TA, TB…Bending surface

Claims

1. A bus bar including a plate-shaped extension portion, When viewed in a cross section intersecting the extension direction of the extension portion, the extending portion has a first main surface, a first side portion facing in a direction different from the first main surface, and a first corner portion connecting the first main surface and the first side portion, The first corner portion has at least one of a curved surface that is convex toward the outside of the extension portion or an inclined surface that is inclined at an angle of more than 45 degrees with respect to the first main surface. Busbar.

2. the first corner portion has the curved surface, The minimum radius of curvature of the curved surface is 1 mm or more. The busbar of claim 1 .

3. the first corner portion has the curved surface, the extension portion has a conductor and an insulating coating covering an outer periphery of the conductor, the minimum radius of curvature of the curved surface is greater than the thickness of the insulating coating; The bus bar according to claim 1 or 2.

4. the first corner portion has the curved surface, the extension portion includes a conductor, an insulating coating covering an outer periphery of the conductor, and a shielding layer covering an outer periphery of the insulating coating; a surface of the first corner portion is formed by a part of a surface of the shield layer; The bus bar according to claim 1 or 2.

5. the minimum radius of curvature of the curved surface is greater than the film thickness of the shield layer; The bus bar according to claim 4.

6. the first corner portion has the curved surface, the extension portion has a conductor and an insulating coating covering an outer periphery of the conductor, the conductor has a first conductor main surface parallel to the first main surface, a first conductor side portion parallel to the first side portion, and a first conductor corner portion connecting the first conductor main surface and the first conductor side portion, The first conductor corner portion has a conductor curved surface that is located on the inner circumferential side of the curved surface and is convex toward the outside of the extension portion. The bus bar according to claim 1 or 2.

7. When viewed from the cross section, the extension portion has a second main surface located on the opposite side to the first main surface in a thickness direction of the extension portion and parallel to the first main surface, and a second corner portion connecting the first side portion and the second main surface, The second corner portion has at least one of a curved surface that is smaller than the curved surface, a sloped surface that is smaller than the sloped surface, or a curved surface that is bent at a right angle. The bus bar according to claim 1 or 2.

8. The first corner portion has an inclined surface inclined at an angle of more than 45 degrees with respect to the first main surface. The busbar of claim 1 .

Images