bus bar

Abstract

A bus bar includes a plate-shaped extension. The extension has a first major surface, a first side portion, and a first corner portion when viewed along a cross section intersecting an extension direction of the extension. The first side portion faces a direction different from the first major surface. The first corner portion connects the first major surface and the first side portion. The first corner portion has at least one surface selected from the group consisting of a curved surface that protrudes toward an outer side of the extension, and an inclined surface that is inclined at an angle exceeding 45 degrees with respect to the first major surface.

Description

Technical Field

[0001] Embodiments of the present invention relate to a busbar.

[0002] This application claims priority based on Japanese Patent Application No. 2024-060565, filed on April 4, 2024 in Japan, the contents of which are incorporated herein by reference. Background Technology

[0003] For example, a busbar can be used as one of the electrical connection components in a vehicle. The busbar has a connection portion for connecting to electrical components and a plate-like extension portion.

[0004] Citation List

[0005] Patent documents

[0006] Patent Document 1

[0007] Japanese Patent Application Publication No. 2023-023721 Summary of the Invention

[0008] Technical issues

[0009] However, depending on the usage environment, the temperature of the busbar can sometimes rise.

[0010] One implementation provides a busbar that can improve heat dissipation.

[0011] means of solving technical problems

[0012] One embodiment of the busbar includes a plate-shaped extension, wherein, when viewed in a cross section intersecting the extension direction, the extension has a first main surface, a first side portion facing a direction different from the first main surface, and a first corner portion connecting the first main surface and the first side portion, and the first corner portion has at least one surface selected from the group consisting of: a curved surface convex toward the outside of the extension, and an inclined surface inclined at an angle of more than 45 degrees relative to the first main surface.

[0013] The effects of the invention

[0014] According to one implementation method, the heat dissipation of the busbar can be improved. Attached Figure Description

[0015] Figure 1 This is a diagram illustrating an example of a vehicle including the busbar of the first embodiment.

[0016] Figure 2 This is a perspective view showing an example of a busbar according to the first embodiment.

[0017] Figure 3 It is along Figure 2 The cross-sectional view taken along line F3-F3 of the busbar shown.

[0018] Figure 4A This is a graph showing the simulation results related to the busbar of the comparative example.

[0019] Figure 4B This is a diagram used to illustrate the airflow around the manifold in the comparative example.

[0020] Figure 5A This is a graph showing simulation results related to the busbar of the first embodiment.

[0021] Figure 5B This is a diagram used to illustrate the airflow around the busbar in the first embodiment.

[0022] Figure 6 This is a graph showing the relationship between the radius of curvature and the cross-sectional area ratio in the first embodiment.

[0023] Figure 7 This is a graph showing the relationship between the radius of curvature and the temperature rise of the busbar in the first embodiment.

[0024] Figure 8 This is a cross-sectional view of a busbar showing a first variation of the first embodiment.

[0025] Figure 9 This is a cross-sectional view of a busbar showing a second variation of the first embodiment.

[0026] Figure 10 This is a cross-sectional view showing the busbar according to the second embodiment.

[0027] Figure 11 This is a graph showing simulation results related to the busbar of the second embodiment.

[0028] Figure 12 This is a cross-sectional view showing an example of an electrical connection device of a modified embodiment of the second embodiment.

[0029] Figure 13 It is along Figure 12 A cross-sectional view of the electrical connection device shown, taken along line F13-F13. Detailed description

[0030] The embodiments will now be described with reference to the accompanying drawings. In this description, configurations having the same or similar functions will be labeled with the same reference numerals, and repeated descriptions of these configurations will sometimes be omitted. In this disclosure, the terms are defined as follows: "Connection" is not limited to mechanical connections, but may also include electrical connections. That is, "connection" is not limited to the case where two elements that are connected are directly connected to each other, but may also include the case where two elements that are connected are connected through other elements in between. The terms "parallel," "orthogonal," "horizontal," "circular," "right-angled," and "identical" can respectively include cases of "substantially parallel," "substantially orthogonal," "substantially horizontal," "substantially circular," "substantially right-angled," and "substantially identical."

[0031] In this disclosure, the X, Y, and Z directions are defined as follows: The X direction is the extension direction of the first extension 23a of the busbar 20 (described later). The Y direction is the width direction of the first extension 23a of the busbar 20. The Z direction is the thickness direction of the first extension 23a of the busbar 20. It should be noted that in the following description, the horizontal direction, as well as up, down, left, and right, are based on the orientation of the busbar 20 when it is in use (e.g., mounted on a vehicle V).

[0032] (First Implementation)

[0033] <1. Composition of the busbar>

[0034] Figure 1 This is a diagram illustrating an example of a vehicle V including the busbar 20 of the first embodiment. The vehicle V is, for example, an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV).

[0035] The vehicle V includes, for example, an electric motor 11, an inverter 12, a high-voltage battery 13, a charging port 14, and multiple busbars 20 (e.g., a first busbar 20A and a second busbar 20B). The electric motor 11, inverter 12, high-voltage battery 13, and charging port 14 are examples of "electrical components".

[0036] Busbar 20 is an electrical connection component that electrically connects multiple electrical components to each other. Figure 1 In the example shown, the first busbar 20A connects the inverter 12 to the high-voltage battery 13. The second busbar 20B connects the charging port 14 to the high-voltage battery 13. The connections of the busbar 20 are not limited to the above example. The busbar 20 can also be used for various electrical components other than those shown in the example.

[0037] Figure 2This is a perspective view showing an example of a busbar 20. The busbar 20 includes, for example, a first connecting portion 21, a second connecting portion 22, and an extension portion 23. In this embodiment, the first connecting portion 21, the second connecting portion 22, and the extension portion 23 are all plate-shaped. That is, the first connecting portion 21, the second connecting portion 22, and the extension portion 23 all have a flat rectangular cross-sectional shape.

[0038] (First connecting part)

[0039] The first connection portion 21 is the portion that connects to a first electrical component that is the object of connection. The first connection portion 21 is provided at one end of the busbar 20. The first connection portion 21 has a through hole 21h through which a fastening component (e.g., a screw, not shown) passes.

[0040] (Second connecting part)

[0041] The second connection portion 22 is the portion that connects to a second electrical component that is another connection object. The second connection portion 22 is provided at the other end of the busbar 20. The second connection portion 22 has a through hole 22h through which a fastening component (e.g., a screw, not shown) passes.

[0042] (Extension)

[0043] The extension 23 is disposed between the first connecting portion 21 and the second connecting portion 22. The extension 23 includes, for example, a first extension 23a, a second extension 23b, and a third extension 23c.

[0044] The first extension 23a extends, for example, horizontally in the X direction. Similarly, the second extension 23b extends, for example, horizontally in the X direction. A third extension 23c is disposed between the first extension 23a and the second extension 23b, connecting the two extensions. The third extension 23c extends, for example, in a direction intersecting the horizontal direction. The shape of the extension 23 is not limited to the above example. For example, the extension 23 may only have the first extension 23a and extend in a straight line, or it may be curved in a more complex manner.

[0045] Figure 3 It is along Figure 2 The cross-sectional view of busbar 20 shown is taken along line F3-F3. The busbar 20 of this embodiment is a busbar with a shielding structure (hereinafter referred to as a "shielded busbar"). In this disclosure, the term "shielded busbar" is used for ease of description only and does not limit the scope of the invention to a specific structure. Busbar 20 includes, for example, a conductor 31, an insulating film 32, and a shielding layer 33.

[0046] (conductor)

[0047] Conductor 31 forms a current-carrying path in busbar 20 for the flow of current. Conductor 31 is, for example, made of metal. Conductor 31 is, for example, a component with a flat rectangular cross-sectional shape.

[0048] (Insulating film)

[0049] The insulating film 32 is an insulating component that covers the outer periphery of the conductor 31. The insulating film 32 is, for example, made of synthetic resin. The insulating film 32 covers the outer periphery of the conductor 31, enclosing the entire outer periphery of the cross-sectional shape of the conductor 31, which has a flat rectangular cross-sectional shape. The insulating film 32 has a film thickness t1. The insulating film 32 is disposed on the extension 23 of the busbar 20. On the other hand, the first connecting portion 21 and the second connecting portion 22 of the busbar 20 are not covered by the insulating film 32 and are exposed outside the busbar 20.

[0050] (Shielding layer)

[0051] The shielding layer 33 is a shielding portion covering the outer periphery of the insulating film 32. The shielding layer 33 is, for example, a shielding portion used to reduce noise. The shielding layer 33 is, for example, a metal film (metal layer), but is not limited thereto. The shielding layer 33 can also be a braid, a mesh structure, etc. In this embodiment, the shielding layer 33 is integrated with the conductor 31 and the insulating film 32. The shielding layer 33 covers the outer periphery of the insulating film 32, for example, surrounding the entire outer periphery of the conductor 31, which has a flat rectangular cross-sectional shape. The shielding layer 33 has a film thickness t2. The shielding layer 33 is disposed on the extension 23 of the busbar 20. On the other hand, the first connecting portion 21 and the second connecting portion 22 of the busbar 20 are not covered by the shielding layer 33 and are exposed outside the busbar 20.

[0052] In this embodiment, the shielding layer 33 forms the outer surface of the busbar 20. The surface of the shielding 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 shielding layer 33 also forms the surfaces of the first to fourth corner portions 51 to 54, which will be described later. The surface of the shielding layer 33 also forms the curved surface RA, which will be described later.

[0053] It should be noted that the busbar 20 is not limited to the shielded busbar described above. For example, the busbar 20 may not have a shielding layer 33, but may be formed of a conductor 31 and an insulating film 32. In this case, the first main surface 41, the second main surface 42, the first side surface 43, the second side surface 44, and the first to fourth corner portions 51 to 54, described later, are formed by the surface of the insulating film 32. As an alternative to the above example, the busbar 20 may also not have an insulating film 32 and a shielding layer 33, but may be formed solely of a conductor 31. In this case, the first main surface 41, the second main surface 42, the first side surface 43, the second side surface 44, and the first to fourth corner portions 51 to 54, described later, are formed by the surface of the conductor 31.

[0054] <2. Corner shape of the busbar>

[0055] Next, the corner shape of the busbar 20 will be explained.

[0056] like Figure 3 As shown, when viewed in a cross section intersecting the extension direction of the extension 23 (e.g., the first extension 23a), the extension 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.

[0057] (First Main Page)

[0058] The first main surface 41 is located at the end of the busbar 20 on the Z-direction side. The first main surface 41 faces the aforementioned Z-direction side. The first main surface 41 is a plane along the X and Y directions. The first main surface 41 is, for example, arranged in a horizontal direction. The first main surface 41, for example, constitutes the upper surface of the busbar 20. The first main surface 41 is larger than the first side surface 43 and the second side surface 44, which will be described later.

[0059] (Second main page)

[0060] The second main surface 42 is located on the opposite side of the first main surface 41 in the Z direction of the busbar 20. 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 aforementioned 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 along the X and Y directions. The second main surface 42 is, for example, arranged in a horizontal direction. The second main surface 42 forms the lower surface of the busbar 20. The second main surface 42 is larger than the first side surface 43 and the second side surface 44, which will be described later.

[0061] (First side view)

[0062] The first side surface 43 is located at the end of the busbar 20 on the Y-direction side. The first side surface 43 faces a direction different from the first main surface 41. The first main surface 41, for example, faces the Y-direction side. The first side surface 43 is, for example, a plane extending along both the X and Y directions. The first side surface 43 is, for example, arranged vertically. The first side surface 43 is an example of a "first side portion". It should be noted that the "first side portion" is not limited to having a planar side surface, and may also not have a planar side surface. For example, in the case where the first side surface 43 does not exist, and the first corner portion 51 and the 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 equivalent to an example of a "first side portion". Therefore, in the following description, the "first side surface 43" may sometimes also be referred to as the "first side portion".

[0063] (Second side view)

[0064] The second side surface 44 is located opposite to the first side surface 43 in the Y direction of the busbar 20. 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 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 along both the X and Y directions. The second side surface 44 is, for example, arranged in a vertical direction. The second side surface 44 is an example of a "second side portion". It should be noted that the "second side portion" is not limited to having a planar side surface, and may also not have a planar side surface. For example, in the case where the second side surface 44 does not exist, and the third triangular portion 53 and the 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 equivalent to an example of a "second side portion".

[0065] (corner)

[0066] like Figure 3 As shown, when viewed in a cross section intersecting the extension direction of the extension 23 (e.g., the first extension 23a), the extension 23 has, for example, a first corner 51, a second corner 52, a third corner 53, and a fourth corner 54.

[0067] A first corner portion 51 is disposed 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. A second corner portion 52 is disposed 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. A third corner portion 53 is disposed 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. A fourth corner portion 54 is disposed 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.

[0068] In this embodiment, the first corner portion 51, the second corner portion 52, the third corner portion 53, and the fourth corner portion 54 each have a curved surface RA protruding outward toward the extension portion 23. In this embodiment, the curved surface RA is a surface equivalent to a quarter circle arc of a perfect circle. In this case, the radius of curvature R1 of the curved surface RA is equivalent to an example of the "minimum radius of curvature of the curved surface". Therefore, in the following description, "radius of curvature R1" may sometimes be referred to as "minimum radius of curvature". In this disclosure, "minimum radius of curvature" refers to the radius of curvature at the point where the radius of curvature is smallest among all points on the curved surface.

[0069] 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 obtained by extending the first main surface 41 along the Y direction, the first corner portion 51 and the third corner portion 53 each have a curved surface RA from the imaginary line V1 within a distance L1 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 obtained by extending the second main surface 42 along the Y direction, the second corner portion 52 and the fourth corner portion 54 each have a curved surface RA from the imaginary line V2 within a distance L2 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.

[0070] From another perspective, the radius of curvature R1 is, for example, greater than the film thickness t1 of the insulating coating 32. The radius of curvature R1 is, for example, greater than the film thickness t2 of the shielding layer 33. It should be noted that the embodiments are not limited to configurations having the above-described dimensions or dimensional relationships.

[0071] <3. The shape of a conductor>

[0072] Next, the shape of conductor 31 will be described.

[0073] like Figure 3 As shown, when viewed in a cross section intersecting the extension direction of the extension 23 (e.g., the first extension 23a), the 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.

[0074] (First conductor principal plane)

[0075] The first conductor main surface 61 is located at the end of the conductor 31 on the Z-direction side. The first conductor main surface 61 is parallel to the first main surface 41. The first conductor main surface 61 is larger than the first conductor side surface 63 and the second conductor side surface 64, which will be described later.

[0076] (Second conductor principal surface)

[0077] The second conductor main surface 62 is located on the opposite side of the first conductor main surface 61 in the Z direction within the conductor 31. The second conductor main surface 62 is located at the end of the conductor 31 on the other side in the Z direction. The second conductor main surface 62 is parallel to the second main surface 42. The second conductor main surface 62 is larger than the first conductor side surface 63 and the second conductor side surface 64, which will be described later.

[0078] (Side view of the first conductor)

[0079] The first conductor side surface 63 is located at the end of conductor 31 on the Y-direction side. 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". It should be noted that the "first conductor side portion" is not limited to having a planar side surface, and may not have a planar side surface. For example, in the case where the first conductor side surface 63 is absent, and the first conductor corner 71 and the second conductor corner 72, described later, are directly adjacent to each other, the boundary between the first conductor corner 71 and the second conductor corner 72 is equivalent to an example of a "first conductor side portion". Therefore, in the following description, the "first conductor side surface 63" may sometimes also be referred to as the "first conductor side portion".

[0080] (Second conductor side)

[0081] The second conductor side surface 64 is located on the opposite side of the first conductor side surface 63 in the Y direction within the conductor 31. 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". It should be noted that the "second conductor side portion" is not limited to having a planar side surface, and may also not have a planar side surface. For example, in the case where the second conductor side surface 64 is absent, and the third conductor corner 73 and the fourth conductor corner 74 described later are directly adjacent to each other, the boundary between the third conductor corner 73 and the fourth conductor corner 74 is equivalent to an example of a "second conductor side portion". Therefore, in the following description, the "second conductor side surface 64" may sometimes also be referred to as the "second conductor side portion".

[0082] (corner)

[0083] like Figure 3 As shown, when viewed in a cross section intersecting the extension direction of the extension 23 (e.g., the first extension 23a), the 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.

[0084] The first conductor corner 71 is located on the inner periphery of the first corner 51. The first conductor corner 71 is disposed between the first conductor main surface 61 and the first conductor side surface 63, and connects the first conductor main surface 61 and the first conductor side surface 63. The second conductor corner 72 is located on the inner periphery of the second corner 52. The second conductor corner 72 is disposed between the second conductor main surface 62 and the first conductor side surface 63, and connects the second conductor main surface 62 and the first conductor side surface 63.

[0085] The third conductor corner 73 is located on the inner periphery of the third corner 53. The third conductor corner 73 is disposed between the first conductor main surface 61 and the second conductor side surface 64, and connects the first conductor main surface 61 and the second conductor side surface 64. The fourth conductor corner 74 is located on the inner periphery of the fourth corner 54. The fourth conductor corner 74 is disposed between the second conductor main surface 62 and the second conductor side surface 64, and connects the second conductor main surface 62 and the second conductor side surface 64.

[0086] In this embodiment, the first conductor corner 71, the second conductor corner 72, the third conductor corner 73, and the fourth conductor corner 74 each have a conductor surface RB protruding outward toward the extension 23. In this embodiment, the conductor surface RB is a curved surface with an arc equivalent to a quarter circle. In this case, the radius of curvature R11 of the conductor surface RB is an example of the "minimum radius of curvature of the surface". Therefore, in the following description, "radius of curvature R11" may sometimes be referred to as "minimum radius of curvature". The radius of curvature R11 is, for example, greater than the film thickness t1 of the insulating coating 32. The radius of curvature R11 is, for example, greater than the film thickness t2 of the shielding layer 33. It should be noted that the embodiment is not limited to the configuration having the above-described dimensions or dimensional relationships.

[0087] <3. Function>

[0088] Next, the function of busbar 20 will be explained. Here, the function of busbar 20X in the comparative example will be explained first. The first to fourth corners 51 to 54 of busbar 20X in the comparative example are all corners that do not have curved surfaces RA, but are bent at right angles.

[0089] Figure 4A This is a graph showing the simulation results related to the busbar 20X of the comparative example. Figure 4A The diagram shows the airflow and air temperature around the busbar 20X as the temperature rises. The inventors' research on this comparative example of the busbar 20X revealed that the airflow around the busbar 20X is not easily stabilized, potentially reducing heat dissipation efficiency.

[0090] Figure 4B This is a diagram used to illustrate the airflow around the manifold 20X in the comparative example. (Example) Figure 4B As shown, when busbar 20X is energized, the temperature of the central portion of busbar 20X rises due to the heat generated by the electrical equipment connected to busbar 20X and / or the heat generated by busbar 20X itself (Joule heating). Subsequently, the heat from the central portion of busbar 20X moves towards the surface portion of busbar 20X (see arrow H in the figure). As a result, the air surrounding busbar 20X is heated.

[0091] In this situation, the air near the first side surface 43 is heated by the first side surface 43 and becomes an upward airflow A rising along the first side surface 43. At this time, in the comparative example's busbar 20X, since the first corner 51 is a right angle, the upward airflow A, after passing the side of the first corner 51, does not easily move smoothly to the top of the first main surface 41, but tends to remain in its original state and continue to rise. As a result, in a certain region above the first main surface 41 (region S in the figure), the air density decreases, and a vortex Aa, in which a portion of the upward airflow A flows downward in the opposite direction, is easily generated. When the vortex Aa is generated, the air near the first main surface 41 does not easily rise smoothly. As a result, the heat dissipation efficiency of the first main surface 41 decreases. This can be confirmed, for example, by the generation of a localized high-temperature area in a portion of the first main surface 41 of the busbar 20X (see reference). Figure 4A ).

[0092] Next, the function of the busbar 20 in this embodiment will be explained.

[0093] Figure 5A This is a graph showing the simulation results related to the busbar 20 of this embodiment. Figure 5A The diagram illustrates the airflow and air temperature around the busbar 20 as its temperature rises. In this embodiment, the inventors' research confirmed that the airflow around the busbar 20 is easily stabilized, thereby improving heat dissipation efficiency.

[0094] Figure 5B This is a diagram used to illustrate the airflow around the manifold 20 in this embodiment. (See diagram for example.) Figure 5B As shown, when busbar 20 is energized, the temperature of the central portion of busbar 20 rises due to the heat generated by the electrical equipment connected to busbar 20 and / or the heat generated by busbar 20 itself (Joule heating). Subsequently, the heat from the central portion of busbar 20 moves towards the surface portion of busbar 20 (see arrow H in the figure). As a result, the air surrounding busbar 20 is heated.

[0095] In this situation, the air near the first side surface 43 is heated by the first side surface 43 and becomes an upward airflow A rising along the first side surface 43. At this time, in the busbar 20 of this embodiment, since the first corner 51 has a curved surface RA, a portion of the upward airflow A can easily move smoothly along the curved surface RA of the first corner 51 to above the first main surface 41. As a result, in a certain region above the first main surface 41, a region with reduced air density is not easily formed. Therefore, the aforementioned vortex Aa is not easily generated. When the vortex Aa is not easily generated, the air near the first main surface 41 can easily rise smoothly, thereby improving the heat dissipation efficiency of the first main surface 41. For example, this can also be confirmed by the fact that a portion of the first main surface 41 of the busbar 20 is not prone to the formation of local high-temperature areas (see reference). Figure 5A ).

[0096] <4. Influence of Surface Dimensions>

[0097] Next, we will explain the effect of the dimensions of the curved surface RA.

[0098] Figure 6 This is a graph showing the relationship between the radius of curvature of the curved surface RA and the cross-sectional area ratio. In this disclosure, the "cross-sectional area ratio" refers to an index obtained by dividing the cross-sectional area of ​​the extension 23 when the first to fourth corner portions 51 to 54 have the curved surface RA by the cross-sectional area of ​​the extension 23 when the first to fourth corner portions 51 to 54 are right angles. Figure 6 As shown, for example, when the radius of curvature of the surface RA is 1 mm or more, it can be confirmed that the cross-sectional area of ​​the extension 23 is significantly reduced.

[0099] Figure 7 This is a graph showing the relationship between the radius of curvature of surface RA and the temperature rise of busbar 20. (See figure) Figure 7 As shown, within a radius of curvature of 5 mm or less, the temperature rise is suppressed compared to the case where the first to fourth corners 51 to 54 are right angles. On the other hand, within a radius of curvature exceeding 5 mm, the temperature rise may be more difficult to suppress compared to the case where the first to fourth corners 51 to 54 are right angles. Therefore, according to Figure 6 and Figure 7 As a result, the radius of curvature of the first corner 51 of the busbar 20 is preferably 1 mm or more and 5 mm or less, more preferably 2 mm or more and 4 mm or less. It should be noted that these dimensions do not limit the scope of this embodiment.

[0100] <5. Advantages>

[0101] In recent years, the current in electric vehicles has been continuously increasing. To cope with this increase in current, it is necessary to increase the cross-sectional area of ​​the busbar. On the other hand, increasing the cross-sectional area of ​​the busbar may reduce its vehicle-mountability due to space constraints. Furthermore, increasing the cross-sectional area of ​​the busbar increases the amount of material used, which may also raise costs.

[0102] Furthermore, the busbar 20, as a shielded busbar, can be used for purposes such as noise reduction. In a shielded busbar, when the surface of the shielding layer 33 is untreated (e.g., without anodizing, polishing, oxidation, etc.), its reflectivity is low, and it may be difficult to expect efficient heat dissipation through radiation. In this case, the temperature of the shielded busbar may rise more easily compared to a busbar with the conductor 31 exposed after the aforementioned surface treatment.

[0103] On the other hand, in this embodiment, the busbar 20 includes a plate-shaped extension 23. Viewed in a cross-section intersecting the extension direction of the extension 23, the extension 23 has a first main surface 41, a first side surface 43 (first side portion) facing a direction different 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 protruding outwards from the extension 23. With this configuration, as described above, the airflow around the busbar 20 is easily stabilized, thereby improving the heat dissipation efficiency of the first main surface 41. As a result, the heat dissipation performance of the busbar 20 can be improved.

[0104] Furthermore, when the first corner 51 has a curved surface RA, the amount of material used in the busbar 20 can be reduced compared to when the first corner 51 is a right angle. As a result, the cost of the busbar 20 can be reduced. Moreover, when the first corner 51 has a curved surface RA, heat dissipation is improved, thus reducing the cross-sectional area of ​​the busbar 20. Reducing the cross-sectional area of ​​the busbar 20 improves its compatibility with the vehicle V. Furthermore, even if the busbar 20 is a shielded busbar, heat dissipation can be improved by having the first corner 51 curved surface RA. Therefore, even when using the busbar 20 as a shielded busbar, the temperature rise of the busbar 20 can be suppressed.

[0105] In this embodiment, the radius of curvature (minimum radius of curvature) R1 of the curved surface RA of the first corner 51 is 1 mm or more. With this configuration, the heat dissipation of the busbar 20 can be improved more easily while suppressing the amount of material used in the busbar 20.

[0106] In this embodiment, the radius of curvature (minimum radius of curvature) R1 of the curved surface RA of the first corner 51 is greater than the film thickness t1 of the insulating film 32. With this configuration, it is easier to improve the heat dissipation of the busbar 20 compared to the case where the radius of curvature R1 of the curved surface RA is less than the film thickness t1 of the insulating film 32.

[0107] In this embodiment, the surface of the first corner 51 is formed from a portion of the surface of the shielding layer 33. With this configuration, even when using the busbar 20 as a shielding busbar, the heat dissipation of the busbar 20 can be improved by having a curved surface RA in the first corner 51.

[0108] In this embodiment, the radius of curvature (minimum radius of curvature) R1 of the curved surface RA of the first corner 51 is greater than the film thickness t2 of the shielding layer 33. With this configuration, it is easier to improve the heat dissipation of the busbar 20 compared to the case where the radius of curvature R1 of the curved surface RA is less than the film thickness t2 of the shielding layer 33.

[0109] In this embodiment, conductor 31 has a first conductor main surface 61 parallel to the first main surface 41, a first conductor side surface 63 parallel to the first side surface 43, and a first conductor corner portion 71 connecting the first conductor main surface 61 and the first conductor side surface 63. The first conductor corner portion 71 is located on the inner periphery of the curved surface RA of the first corner portion 51 and has a conductor curved surface RB protruding outward toward the extension 23. With this configuration, it is easier to set a larger radius of curvature for the curved surface RA of the first corner portion 51 compared to the case where the first conductor corner portion 71 is a right angle. As a result, it is easier to improve the heat dissipation of the busbar 20.

[0110] (Variation example)

[0111] Next, the busbar 20 of several modified examples will be described. It should be noted that in each modified example, except for the configuration described below, the other configurations are the same as those in the first embodiment.

[0112] (First variation)

[0113] Figure 8 This is a cross-sectional view of the busbar 20 showing a first variation of the first embodiment. In the first variation, the first to fourth corner portions 51 to 64 each have a curved surface RC. The curved surface RC is an arc-shaped curved surface corresponding to a portion of an ellipse. In this case, the radius of curvature of the curved surface RC varies depending on its position on the surface of the curved surface RC. In this variation, the minimum radius of curvature R2 of the curved surface RC is 1 mm or more. For example, the minimum radius of curvature R2 of the curved surface RC is 1 mm or more and 5 mm or less.

[0114] From another perspective, assuming an imaginary line V1 is obtained by extending the first main surface 41 along the Y direction, the first corner portion 51 and the third corner portion 53 each have a curved surface RC from the imaginary line V1 within a distance L1 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 is obtained by extending the second main surface 42 along the Y direction, the second corner portion 52 and the fourth corner portion 54 each have a curved surface RC from the imaginary line V2 within a distance L2 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.

[0115] In this modified example, assuming an imaginary line V3 is obtained by extending the first side surface 43 along the Z direction, the first corner portion 51 and the second corner portion 52 each have a curved surface RC within a distance L3 in the Y direction from the imaginary line V3. The distance L3 is, for example, less than the distance L1. The distance L3 is, for example, less than the distance L2.

[0116] From another perspective, the minimum radius of curvature R2 is, for example, greater than the film thickness t1 of the insulating coating 32. The minimum radius of curvature R2 is, for example, greater than the film thickness t2 of the shielding layer 33. It should be noted that the implementation is not limited to configurations having the above-described dimensions or dimensional relationships.

[0117] In this modified example, the first to fourth conductor corners 71 to 74 each have a conductor surface RD located on the inner periphery of the curved surface RC. The conductor surface RD is, for example, an arc-shaped curved surface equivalent to a part of an ellipse. The conductor surface RD is, for example, a curved surface with a shape similar to that of the curved surface RC.

[0118] Even with this configuration, the curved surface RC of the first corner 51 prevents the generation of eddy currents Aa above the first main surface 41, thereby improving the heat dissipation efficiency of the first main surface 41. As a result, the heat dissipation performance of the busbar 20 is improved.

[0119] (Second variation)

[0120] Figure 9 This is a cross-sectional view of the busbar 20 showing a second variation of the first embodiment. In the second variation, the first to fourth corner portions 51 to 54 each have an inclined surface CA instead of a curved surface RA. For example, the first corner portion 51 and the third corner portion 53 are inclined surfaces that are inclined at an angle α greater than 45 degrees relative to the first main surface 41 (e.g., 60 degrees relative to the first main surface 41). Similarly, the second corner portion 52 and the fourth corner portion 54 are inclined surfaces that are inclined at an angle α greater than 45 degrees relative to the second main surface 42 (e.g., 60 degrees relative to the second main surface 42).

[0121] In this modified example, the first to fourth conductor corners 71 to 74 each have an inclined surface CB located on the inner periphery of the inclined surface CA. The first conductor corner 71 and the third conductor corner 73 are inclined surfaces that are inclined at an angle α greater than 45 degrees relative to the first conductor main surface 61 (for example, 60 degrees relative to the first conductor main surface 61). Similarly, the second conductor corner 72 and the fourth conductor corner 74 are inclined surfaces that are inclined at an angle α greater than 45 degrees relative to the second conductor main surface 62 (for example, 60 degrees relative to the second conductor main surface 62).

[0122] Even with this configuration, the inclined surface CA of the first corner 51 makes it less likely for eddy currents 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' experiments have shown that when the inclined surface CA is inclined at an angle greater than 45 degrees relative to the first main surface 41, the heat dissipation efficiency of the first main surface 41 is improved compared to when the angle of the inclined surface CA relative to the first main surface 41 is less than 45 degrees.

[0123] (Second Implementation)

[0124] Next, the second embodiment will be described. The difference between the second embodiment and the first embodiment is that the shape of the upper surface side and the lower surface side of the extension 23 of the busbar 20 are asymmetrical. It should be noted that, except for the configuration described below, the remaining configuration is the same as that of the first embodiment.

[0125] Figure 10 This is a cross-sectional view showing the busbar 20 according to the second embodiment. In this embodiment, similar to the first embodiment, the first corner portion 51 and the third corner portion 53 each have a curved surface RA. On the other hand, the second corner portion 52 and the fourth corner portion 54 are right angles. That is, the second corner portion 52 and the fourth corner portion 54 each have a bent surface TA that bends at a right angle.

[0126] In this embodiment, similar to the first embodiment, the first conductor corner 71 and the third conductor corner 73 each have a conductor curved surface RB. On the other hand, the second conductor corner 72 and the fourth conductor corner 74 are right angles. That is, the second conductor corner 72 and the fourth conductor corner 74 each have a bent surface TB that is bent at a right angle.

[0127] Figure 11 This is a graph showing simulation results related to the busbar 20 of the second embodiment. (See figure.) Figure 11 As shown, when the first corner portion 51 has a curved surface RA, even if the second corner portion 52 does not have a curved surface RA, it is not easy to generate eddy currents Aa above the first main surface 41, thereby improving the heat dissipation efficiency of the first main surface 41. As a result, the heat dissipation performance of the busbar 20 can be improved.

[0128] It should be noted that the second embodiment is not limited to the examples described above. For example, the second corner portion 52 and the fourth corner portion 54 may each have a surface RA smaller than the surface RA of the first corner portion 51 and the third corner portion 53. That is, the radius of curvature R1 of the surface RA of the second corner portion 52 and the fourth corner portion 54 may also be smaller than the radius of curvature R1 of the surface RA of the first corner portion 51 and the third corner portion 53. Furthermore, the second corner portion 52 and the fourth corner portion 54 may each have a surface RC smaller than the surface RC of the first corner portion 51 and the third corner portion 53. That is, the minimum radius of curvature R1 of the surface RC of the second corner portion 52 and the fourth corner portion 54 may also be smaller than the minimum radius of curvature R1 of the surface RC of the first corner portion 51 and the third corner portion 53. Furthermore, the second corner portion 52 and the fourth corner portion 54 may each have an inclined surface CA smaller than the inclined surface CA of the first corner portion 51 and the third corner portion 53.

[0129] (Variation example)

[0130] Next, the busbar 20 of the modified example will be described. It should be noted that, in this modified example, except for the configuration described below, the remaining configuration is the same as that of the second embodiment.

[0131] Figure 12 This is a diagram illustrating an example of an electrical connection device 100 including a busbar 20 according to the second embodiment. The electrical connection device 100 is, for example, an electrical connector referred to as an electrical junction box or junction box. The electrical connection device 100 includes, for example, a housing 101, a first electronic component 102, a second electronic component 103, a heat transfer component 104, and a busbar 20.

[0132] The housing 101 has a base component 101a and a cover component 101b. The base component 101a is made of, for example, synthetic resin and is insulating. The base component 101a is an example of a "first housing component". The cover component 101b is made of, for example, synthetic resin and is insulating. The cover component 101b is an example of a "second housing component". In this modified example, the housing 101 is formed by combining the base component 101a and the cover component 101b. The first electronic component 102, the second electronic component 103, the heat transfer component 104, and the busbar 20 are housed within the housing 101.

[0133] The first electronic component 102 and the second electronic component 103 are, for example, electronic components used for switching power-on states or for protection. The first electronic component 102 and the second electronic component 103 may be, for example, connectors, fuses, relays (e.g., mechanical relays or semiconductor relays), capacitors, branch components, electronic control devices, or electronic component devices integrating two or more of these, but are not limited thereto. The first connecting portion 21 of the busbar 20 is connected to the first electronic component 102 via a fastening member FS. The second connecting portion 22 of the busbar 20 is connected to the second electronic component 103 via a fastening member FS. Thus, the busbar 20 electrically connects the first electronic component 102 and the second electronic component 103 to each other.

[0134] A heat transfer component 104 is disposed between a portion of the extension 23 of the busbar 20 and the base component 101a. The heat transfer component 104 is a resin or metal component with excellent thermal conductivity. The heat transfer component 104 transfers a portion of the heat from the busbar 20 to the base component 101a. As a result, a portion of the heat from the busbar 20 is dissipated from the base component 101a to the outside of the electrical connection device 100.

[0135] Figure 13 It is along Figure 12A cross-sectional view of the F13-F13 line of the electrical connection device 100 shown. In this modified example, the busbar 20 does not have an insulating film 32 or a shielding layer 33. In this modified example, 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. In addition, the surface of the conductor 31 also forms first to fourth corner portions 51 to 54.

[0136] In this modified example, the first corner portion 51 and the third corner portion 53 each have a curved surface RA. On the other hand, the second corner portion 52 and the fourth corner portion 54 are right angles. That is, the second corner portion 52 and the fourth corner portion 54 each have a bent surface TA that is bent at a right angle. In this modified example, the heat transfer member 104 is in contact with the second main surface 42, the second corner portion 52, and the fourth corner portion 54.

[0137] With this configuration, since the first corner 51 has a curved surface RA, eddy currents 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. Furthermore, when the second corner 52 is a right angle and contacts the heat transfer component 104, the contact area between the busbar 20 and the heat transfer component 104 can be increased. As a result, the heat dissipation performance of the busbar 20 can be further improved. It should be noted that, similar to the first embodiment, the busbar 20 may also have an insulating film 32, or it may have both an insulating film 32 and a shielding layer 33.

[0138] 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 embodiments or modifications described above can be combined with each other. The first to fourth corner portions 51 to 54 are not limited to having only one of the curved surface RA and the inclined surface CA, but may also have a combination of the curved surface RA and the inclined surface CA. For example, the curved surface RA may be provided in a part of the first corner portion 51, and the inclined surface CA may be provided in another part of the first corner portion 51.

[0139] Industrial applicability

[0140] According to this disclosure, the heat dissipation of the busbar can be improved.

[0141] Figure Labels

[0142] 20 busbars

[0143] 21 First connecting part

[0144] 22 Second connecting part

[0145] Extensions 23, 23a, 23b, and 23c

[0146] 31 Conductors

[0147] 32 Insulating film

[0148] 33 Shielding layer

[0149] 41 First Main Face

[0150] 42 Second Main Face

[0151] 43 First side view (first side section)

[0152] 44 Second side view (second side part)

[0153] 51 First Corner

[0154] 52 Second corner

[0155] 53 Third Corner

[0156] 54. Fourth corner

[0157] 61 First Conductor Principal Surface

[0158] 62 Second conductor principal surface

[0159] 63 First conductor side surface (first conductor side portion)

[0160] 64 Second conductor side surface (second conductor side portion)

[0161] 71 First conductor corner

[0162] 72 Second conductor corner

[0163] 73 Third conductor corner

[0164] 74. Fourth conductor corner

[0165] V vehicle

[0166] RA, RB, RC, RD surfaces

[0167] CA, CB inclined surfaces

[0168] TA, TB Bending Surface

Claims

1. A busbar comprising a plate-shaped extension, wherein, When viewed in a cross section intersecting the extension direction of the extension, The extension has a first main surface, a first side portion facing 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 has at least one surface selected from the group consisting of: a curved surface protruding outward toward the extension, and an inclined surface that is inclined at an angle of more than 45 degrees relative to the first main surface.

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

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

4. The busbar according to claim 1 or 2, wherein, The first corner portion has the curved surface. The extension has a conductor, an insulating film covering the outer periphery of the conductor, and a shielding layer covering the outer periphery of the insulating film. The surface of the first corner is formed from a portion of the surface of the shielding layer.

5. The busbar according to claim 4, wherein, The minimum radius of curvature of the surface is greater than the thickness of the shielding layer.

6. The busbar according to claim 1 or 2, wherein, The first corner portion has the curved surface. The extension has a conductor and an insulating film covering the 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 has a conductor surface located on the inner periphery of the surface and protruding outward toward the extension.

7. The busbar according to claim 1 or 2, wherein, When viewed in the cross section, The extension has a second main surface and a second corner portion. The second main surface is located on the opposite side of the first main surface and parallel to the first main surface in the thickness direction of the extension. The second corner portion connects the first side portion and the second main surface. The second corner has at least one face selected from the group consisting of: a curved surface smaller than the curved surface, an inclined surface smaller than the inclined surface, and a bent surface bent at a right angle.

8. The busbar according to claim 1, wherein, The first corner has an inclined surface that is tilted at an angle of more than 45 degrees relative to the first main surface.

Images