Bus bar and bus bar production method

Abstract

This bus bar includes a plate-shaped extension part. The extension part includes: a conductor; an insulation coating covering an outer periphery of the conductor; a metallic first braid covering an outer periphery of the insulation coating; and a synthetic resin second braid provided in at least a part in an extension direction of the extension part and covering an outer periphery of the first braid.

Description

Busbar and method for manufacturing busbar

[0001] This application claims priority to Japanese Patent Application No. 2024-121950, filed on July 29, 2024, the contents of which are incorporated herein by reference.

[0002] 2. Description of the Related Art Bus bars are used as electrical connection members for vehicles, for example. The bus bars have a connection portion that is connected to an electrical component and a plate-like extension portion.

[0003] Japanese Patent Application Laid-Open No. 2023-023721

[0004] However, bus bars may be covered with a member having shielding properties. Depending on how the bus bars are covered, the shielding performance of the bus bars may deteriorate over time.

[0005] One embodiment provides a bus bar whose shielding performance is unlikely to deteriorate even after long-term use.

[0006] In one embodiment, the busbar includes a plate-shaped extension portion including a conductor, an insulating coating covering an outer periphery of the conductor, a first metal braid covering the outer periphery of the insulating coating, and a second synthetic resin braid provided at least partially in the extension direction of the extension portion and covering the outer periphery of the first braid.

[0007] In one embodiment, a method of manufacturing a busbar includes preparing a busbar body including a conductor and an insulating coating covering an outer periphery of the conductor, passing the busbar body through a first metal braid while deforming the first braid in a direction that expands a cylindrical internal space of the first braid, deforming the first braid in a direction that reduces the internal space of the first braid after the busbar body has been passed through the first braid, passing the busbar body and the first braid through a second synthetic resin braid while deforming the second synthetic resin braid in a direction that expands a cylindrical internal space of the second braid, and passing the busbar body and the first braid through the second braid, deforming the second braid in a direction that reduces the internal space of the second braid after the busbar body has been passed through the second braid.

[0008] According to one embodiment, the shielding performance of the bus bar is unlikely to deteriorate even with long-term use.

[0009] 1 is a diagram showing an example of a vehicle including a busbar according to an embodiment. 2 is a perspective view showing an example of a busbar according to an embodiment. 3 is a cross-sectional view taken along line F3-F3 of the busbar shown in FIG. 2. 4 is a flowchart showing an example of a method for manufacturing a busbar according to an embodiment. 5 is a perspective view showing a modified example of the embodiment.

[0010] 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 a direct connection between two elements to be connected, but may also include a connection between two elements to be connected via another element interposed therebetween. "Parallel," "horizontal," "perpendicular," or "same" may include the cases of "approximately parallel," "approximately horizontal," "approximately perpendicular," or "same," respectively.

[0011] In the present 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).

[0012] In the following, when there is no distinction between the X direction and the Y direction, they may be referred to as the "horizontal direction." In the following, the Z direction may be referred to as the "vertical direction." In addition, in the following, the +Z direction side may be referred to as the "upper" and the -Z direction side may be referred to as the "lower."

[0013] 1 is a diagram illustrating an example of a vehicle V including a bus bar 20 according to an embodiment. The vehicle V is an electric vehicle such as an EV (Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a PHEV (Plug-in Hybrid Electric Vehicle).

[0014] The vehicle V includes, 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."

[0015] 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.

[0016] 2 is a perspective view showing an example of the bus bar 20. The bus bar 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.

[0017] (First Connection Portion) The first connection portion 21 is a portion that is connected to a first electrical 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.

[0018] (Second Connection Portion) The second connection portion 22 is a portion that is connected to a second electrical component, which is another connection target. The second connection portion 22 is provided at the other end of the bus bar 20. The second connection portion 22 has an insertion hole 22h through which a fastening member (e.g., a screw) (not shown) is passed.

[0019] (Extended portion) The extended portion 23 is provided between the first connecting portion 21 and the second connecting portion 22. The extended portion 23 has, for example, a first extended portion 23a, a second extended portion 23b, and a third extended portion 23c.

[0020] The first extension portion 23a extends, for example, in the X direction along the horizontal direction. Similarly, the second extension portion 23b extends, for example, in the X direction along the horizontal direction. The third extension portion 23c is provided between the first extension portion 23a and the second extension portion 23b and connects the first extension portion 23a and the second extension portion 23b. The third extension portion 23c extends, for example, in a direction intersecting the horizontal direction. Note that the shape of the extension portion 23 is not limited to the above example. For example, the extension portion 23 may have only the first extension portion 23a and extend linearly, or may be bent in a more complex manner.

[0021] 3 is a cross-sectional view of the bus bar 20 taken along line F3-F3 in FIG. 2. The bus bar 20 of this embodiment is a bus bar having a shielded structure (hereinafter referred to as a "shielded bus bar"). Note that the term "shielded bus bar" used in this disclosure is for the sake of convenience and does not limit the scope of the invention to a specific structure. The bus bar 20 includes, for example, a conductor 31, an insulating coating 32, a first braid 33, and a second braid 34. Note that the configuration including the conductor 31 and the insulating coating 32 is also referred to as a bus bar main body 99.

[0022] (Conductor) The conductor 31 forms a current path through which current flows in the bus bar 20. The conductor 31 is made of, for example, metal. For example, the conductor 31 is made of aluminum, an aluminum alloy, copper, or a copper alloy. The conductor 31 is, for example, a member having a flat rectangular cross-sectional shape.

[0023] (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 is provided on the extension portion 23 of the bus bar 20. On the other hand, the first connection portion 21 and the second connection portion 22 of the bus bar 20 are not covered by the insulating coating 32 and are exposed to the outside of the bus bar 20.

[0024] (First Braid) The first braid 33 is a shield portion that covers the outer periphery of the insulating coating 32. The first braid 33 is, for example, a shield portion for noise reduction. The first braid 33 is, for example, a metallic braid. For example, the first braid 33 includes aluminum, an aluminum alloy, copper, or a copper alloy. The first braid 33 is preferably integrated with the conductor 31 and the insulating coating 32, but is not limited thereto. In the present disclosure, "integrated" refers to a state in which the member is in close contact with another member. For example, in this embodiment, the first braid 33 is integrated with the conductor 31 and the insulating coating 32 by being in close contact with the insulating coating 32. In this case, there is no air gap between the first braid 33 and the insulating coating 32. For example, for a conductor 31 having a flat rectangular cross-sectional shape, the first braid 33 covers the outer periphery of the insulating coating 32 so as to surround the entire periphery of the cross-sectional shape. Since the first braid 33 is in contact with the insulating coating 32, heat can be transferred from the insulating coating 32. The first braid 33 is provided on the extension portion 23 of the bus bar 20. On the other hand, the first connection portion 21 and the second connection portion 22 of the bus bar 20 are not covered by the first braid 33 and are exposed to the outside of the bus bar 20.

[0025] Even when the first braid 33 has recovered from deformation at a recovery rate described below, the inner surface of the first braid 33 is in contact with the insulating coating 32 .

[0026] For example, in this embodiment, the first braid 33 is cylindrical and deformable in a direction that expands and contracts the internal space of the first braid. In this case, the first braid 33 covers the outer periphery of the insulating coating 32 while being deformed so that the inner periphery of the first braid 33 is pressed against the outer periphery of the insulating coating 32. The first braid 33 can expand its internal space by contracting in the axial direction. Also, the first braid 33 can contract its internal space by stretching it in the axial direction.

[0027] (Second Braid) The second braid 34 is a protective component that covers the outer periphery of the first braid 33. The second braid 34 is, for example, a braid made of synthetic resin. For example, the second braid 34 includes polyethylene terephthalate (PET), polyamide (PA), or polyphenylene sulfide (PPS). The braid density of the second braid 34 is greater than the braid density of the first braid 33. The second braid 34 is preferably, but not limited to, integrated with the conductor 31, the insulating coating 32, and the first braid 33. For example, in this embodiment, the second braid 34 is in close contact with the first braid 33, thereby being integrated with the conductor 31, the insulating coating 32, and the first braid 33. In this case, there is no air layer between the second braid 34 and the first braid 33. For example, when the conductor 31 has a flat rectangular cross-sectional shape, the second braid 34 covers the outer periphery of the first braid 33 so as to surround the entire periphery of the cross-sectional shape. Since the second braid 34 is in contact with the first braid 33, heat can be transferred from the first braid 33. The second braid 34 is provided in at least a portion of the extension direction of the extension portion 23 of the bus bar 20. For example, in this embodiment, the second braid 34 is provided across the entire extension direction of the extension portion 23. On the other hand, the first connection portion 21 and the second connection portion 22 of the bus bar 20 are not covered by the second braid 34 and are exposed to the outside of the bus bar 20.

[0028] For example, in this embodiment, the second braid 34 is cylindrical and can be deformed in a direction to expand and contract the internal space of the second braid. In this case, the second braid 34 covers the outer periphery of the first braid 33 in a deformed state such that the inner periphery of the second braid 34 is pressed against the outer periphery of the first braid 33. The second braid 34 can expand the internal space by contracting in the axial direction. Furthermore, the second braid 34 can contract the internal space by stretching in the axial direction.

[0029] Even when the second braid 34 has returned to its original state at a return rate described below, the inner surface of the second braid 34 is in contact with the first braid 33 .

[0030] In this embodiment, the first braid 33 and the second braid 34 are cylindrical, and the following relationship exists between the first braid 33 and the second braid 34. When a force is applied to the first braid 33 (the same applies to the "second braid 34"), which is a cylindrical braid, in a direction that contracts it in the axial direction of the tube, the mesh size of some of the braids increases, thereby expanding the internal space. When a force is applied to the first braid 33 (the same applies to the "second braid 34"), which is a cylindrical braid, in a direction that stretches it in the axial direction of the tube, the mesh size of some of the braids decreases, thereby reducing the internal space. In the present disclosure, the return rate is the rate at which the cylindrical braid deforms from a state in which the internal space of the cylindrical braid is contracted to a state in which the internal space of the cylindrical braid is expanded when an external force is released while the internal space of the cylindrical braid is contracted. The return rate is greater for the second braid 34 than for the first braid 33. That is, the second braid 34 made of synthetic resin undergoes greater changes in shape than the first braid 33 made of metal.

[0031] In order for the second braid 34 to deform the first braid 33 so as to press it against the outer peripheral surface of the insulating coating 32, the following relationship preferably holds when the busbar main body 99 covered by the first braid 33 is passed through the second braid 34: Before the busbar main body 99 is passed through the second braid 34 and in a state in which the second braid 34 is fully stretched, the inner diameter of the second braid 34 is smaller than the dimension value of the width direction (Y direction) of the flat cross section of the busbar main body 99 to which the first braid 33 is attached. Before the busbar main body 99 is passed through the second braid 34 and in a state in which the first braid 33 and the second braid 34 are fully stretched, the inner diameter of the second braid 34 is equal to or smaller than the outer diameter of the first braid 33. Preferably, the inner diameter of the second braid 34 is smaller than the outer diameter of the first braid.

[0032] In the present embodiment, the second braid 34 forms the outer surface of the busbar 20. The second braid 34 covers the first main surface 41, the second main surface 42, the first side surface 43, and the second side surface 44, which will be described later. As described above, in the present embodiment, the second braid 34 is integrated with the conductor 31, the insulating coating 32, and the first braid 33. That is, the second braid 34 covers the first braid 33 so as to fit along the first conductor main surface 61, the second conductor main surface 62, the first conductor side surface 63, and the second conductor side surface 64, which will be described later. The second braid 34 may also cover the first braid 33 so as to fit along the surfaces of the first to fourth corners 51 to 54, which will be described later. In addition, if a curved surface RA, which will be described later, is formed on the surface of the first braid 33, the second braid 34 may fit along the curved surface RA.

[0033] The bus bar 20 is not limited to the shielded bus bar described above. The first braid 33 of the bus bar 20 may be a braided tape made of a metal braid. The second braid 34 of the bus bar 20 may be a wrapping tube made of a synthetic resin braid.

[0034] 3 , when viewed in a cross section intersecting the extension direction of extension portion 23 (e.g., first extension portion 23a), first braid 33 has, for example, a first main surface 41, a second main surface 42, a first side surface 43, and a second side surface 44. The first main surface 41 is located at one end of busbar 20 in the Z direction. For example, first main surface 41 faces the one side in the Z direction. The second main surface 42 is located at the opposite side of busbar 20 from first main surface 41 in the Z direction. For example, second main surface 42 is located at the other end of busbar 20 in the Z direction. The first side surface 43 is located at one end of busbar 20 in the Y direction. For example, first side surface 43 faces a direction different from that of first main surface 41. 3, the first braid 33 may have, for example, a first corner 51, a second corner 52, a third corner 53, and a fourth corner 54. Each of the first corner 51, the second corner 52, the third corner 53, and the fourth corner 54 is provided between two predetermined surfaces of the first braid 33 and connects the two predetermined surfaces.

[0035] 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 .

[0036] As described above, in this embodiment, the first braid 33 is integrated with the conductor 31 and the insulating coating 32. That is, the first braid 33 covers the insulating coating 32 so as to follow the first conductor principal surface 61, the second conductor principal surface 62, the first conductor side surface 63, and the second conductor side surface 64 described below. For example, the first principal surface 41 follows the first conductor principal surface 61. For example, the second principal surface 42 follows the second conductor main surface 62. For example, the first side surface 43 follows the first conductor side surface 63. For example, the second side surface 44 follows the second conductor side surface 64. In addition, in this embodiment, the curved surface RA of the first braid 33 follows the conductor curved surface RB described below.

[0037] 3. Outer Shape of the 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 the extension portion 23 (e.g., the first extension portion 23a), the conductor 31 has, for example, a first conductor principal surface 61, a second conductor principal surface 62, a first conductor side surface 63, and a second conductor side surface 64. 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 second conductor principal surface 62 is located at the opposite end of the conductor 31 in the Z direction from the first conductor principal surface 61. For example, the second conductor principal surface 62 is located at the other end of the conductor 31 in the Z direction. The second conductor principal surface 62 is parallel to the second principal surface 42. 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 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. When viewed in the cross section shown in FIG. 3 , the conductor 31 may have, for example, a first conductor corner 71, a second conductor corner 72, a third conductor corner 73, and a fourth conductor corner 74. The first conductor corner 71, the second conductor corner 72, the third conductor corner 73, and the fourth conductor corner 74 are each provided between two predetermined surfaces of the conductor 31 and connect the two predetermined surfaces.

[0038] 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 .

[0039] 3 , when viewed in a cross section intersecting the extension direction of extension portion 23 (e.g., first extension portion 23a), second braid 34 has, for example, a first main surface 81, a second main surface 82, a first side surface 83, and a second side surface 84. The first main surface 81 is located at one end of busbar 20 in the Z direction. For example, first main surface 81 faces the one side in the Z direction. The second main surface 82 is located at the opposite side of busbar 20 from first main surface 81 in the Z direction. For example, second main surface 82 is located at the other end of busbar 20 in the Z direction. The first side surface 83 is located at one end of busbar 20 in the Y direction. For example, first side surface 83 faces a direction different from that of first main surface 81. 3, the second braid 34 may have, for example, a first corner 91, a second corner 92, a third corner 93, and a fourth corner 94. Each of the first corner 91, the second corner 92, the third corner 93, and the fourth corner 94 is provided between two predetermined surfaces of the second braid 34 and connects the two predetermined surfaces.

[0040] In this embodiment, each of the first corner 91 , the second corner 92 , the third corner 93 , and the fourth corner 94 has a curved surface RC that is convex toward the outside of the extension portion 23 .

[0041] As described above, in this embodiment, the second braid 34 is integrated with the conductor 31, the insulating coating 32, and the first braid 33. That is, the second braid 34 covers the first braid 33 so as to follow the first main surface 41, the second main surface 42, the first side surface 43, and the second side surface 44. For example, the first main surface 81 follows the first main surface 41. For example, the second main surface 82 follows the second main surface 42. For example, the first side surface 83 follows the first side surface 43. For example, the second side surface 84 follows the second side surface 44. In addition, in this embodiment, the curved surface RC of the second braid 34 follows the curved surface RA.

[0042] 3. Manufacturing Method Next, a description will be given of an example of a method for manufacturing the bus bar 20 according to an embodiment. The example of the method for manufacturing the bus bar 20 according to an embodiment is carried out according to the flow shown in FIG.

[0043] First, the worker prepares the busbar body 99 including the conductor 31 and the insulating coating 32 covering the outer periphery of the conductor 31 (step ST10: preparing step).

[0044] Next, the worker passes the busbar main body 99 through the first braid 33, while deforming the first braid 33 in a direction that expands the cylindrical internal space of the metal first braid 33. After the busbar main body 99 is passed through the first braid 33, the worker deforms the first braid 33 in a direction that reduces the internal space of the first braid 33 (step ST11: step of deforming the first braid). By inserting the busbar main body 99 into the expanded first braid 33, the first braid 33 covers the busbar main body 99. As a result, the first braid 33 provides electromagnetic shielding for the busbar main body 99. In this case, if a conductor curved surface RB is formed on the surface of the conductor 31 in step ST10, the first braid 33 is more likely to fit tightly against the busbar main body 99 than if the first to fourth corners 71 to 74 are right angles.

[0045] Next, the worker passes the busbar main body 99 and the first braid 33 through the second braid 34, which is made of synthetic resin, while deforming the second braid 34 in a direction that expands the cylindrical internal space of the second braid 34. After the busbar main body 99 and the first braid 33 are passed through the second braid 34, the worker deforms the second braid 34 in a direction that reduces the internal space of the second braid 34 (step ST12: step of deforming the second braid). At this time, if the surface of the first braid 33 has a curved surface RA formed thereon in step ST10, the second braid 34 is more likely to be in close contact with the busbar main body 99 and the first braid 33 than if the first to fourth corners 51-54 were right angles. At this point, the busbar main body 99 covered by the first braid 33 and the second braid 34 is manufactured (end).

[0046] 4. Operation Consider a comparative example of a busbar (hereinafter referred to as "busbar Z") in which a cylindrical metal braid is attached to a busbar main body 99 with a reduced diameter. In this comparative example, the internal space of the metal braid is reduced, and the metal braid covers the busbar main body 99, making it easier to maintain close contact with the busbar main body 99. Therefore, when the busbar Z interferes with a surrounding component, the metal braid is likely to apply an impact to the busbar. This may result in loud noise from the busbar Z and / or deformation (e.g., disorder) of the metal braid.

[0047] On the other hand, in this embodiment, the busbar 20 includes a plate-shaped extension portion 23. This extension portion 23 includes a conductor 31, an insulating coating 32 covering the outer periphery of the conductor 31, a metal first braid 33 covering the outer periphery of the insulating coating 32, and a synthetic resin second braid 34 provided at least partially in the extension direction of the extension portion 23 and covering the outer periphery of the first braid 33. With this configuration, the second braid 34 is exposed to the outside, making it less likely for the first braid 33 to interfere with surrounding components. Since some of the braids in the first braid 33 are less likely to fray, the busbar main body 99 is less likely to be exposed from the first braid 33. As described above, this embodiment provides a busbar whose shielding performance is less likely to deteriorate even with long-term use.

[0048] In addition, in this embodiment, since the second braid 34 is exposed to the outside, interference between the first braid 33 and surrounding components is less likely to occur, and the first braid 33 is less likely to fall off from the busbar main body 99.

[0049] Furthermore, in this embodiment, the second braid 34 of the busbar 20 is exposed to the outside more than the first braid 33. With this configuration, heat generated from the conductor 31 is transferred from the first braid 33 to the second braid 34, and the heat is radiated from the second braid 34. The emissivity (thermal emissivity) of the second braid 34, which is made of synthetic resin, is higher than the emissivity of the first braid 33, which is made of metal. This improves the heat dissipation performance of the busbar 20. For example, the emissivity of aluminum is less than 0.1, while the emissivity of synthetic resin exceeds 0.9.

[0050] Furthermore, since the second braid 34 is exposed more to the outside than the first braid 33, the first braid 33 is less likely to deform in a direction that expands the internal space, and the first braid 33 is more likely to maintain contact (e.g., tight contact) with the insulating coating 32. For these reasons, the first braid 33 is more likely to function as a shield.

[0051] In this embodiment, the conductor 31 has a flat rectangular cross-sectional shape, the first braid 33 covers the outer periphery of the insulating coating 32 so as to surround the entire periphery of the cross-sectional shape, and the second braid 34 covers the outer periphery of the first braid 33 so as to surround the entire periphery of the cross-sectional shape. This configuration makes it even more unlikely that some of the braids in the first braid 33 will fray or that the first braid 33 will fall off the busbar body.

[0052] In this embodiment, the braid density of the second braid 34 is greater than the braid density of the first braid 33. With this configuration, the externally exposed area of ​​the first braid 33 is reduced, making the first braid 33 less likely to fray. In addition, the surface area of ​​the second braid 34 is increased, improving heat radiation properties.

[0053] In this embodiment, the second braid 34 is cylindrical and deformable in a direction that expands and contracts the internal space of the second braid, and covers the outer periphery of the first braid 33 in a deformed state such that the inner circumferential surface of the second braid 34 is pressed against the outer circumferential surface of the first braid 33. With this configuration, the adhesion between the second braid 34 and the first braid 33 is improved, thereby improving heat dissipation.

[0054] In this embodiment, the first braid 33 is cylindrical and deformable in both directions, expanding and contracting the internal space of the first braid, and the second braid 34 is cylindrical and deformable in both directions, expanding and contracting the internal space of the second braid. When no external force is applied, the return rate of the second braid 34, which changes from a state in which the internal space of the second braid 34 is contracted to a state in which the internal space of the second braid 34 is expanded, is greater than the return rate of the first braid 33, which changes from a state in which the internal space of the first braid 33 is contracted to a state in which the internal space of the first braid 33 is expanded. With this configuration, the second braid 34 is expanded compared to the first braid 33, and is therefore in a state in which it can be deformed again in the contracting direction (a state in which it is easy to absorb shock). The presence of the second braid 34 makes it easier to absorb shock than when only the first braid 33 is present.

[0055] <Modifications> Next, several modifications will be described. Note that in each modification, the configuration other than that described below is the same as the configuration of the first embodiment.

[0056] (First Modification) In the above disclosure, the second braid 34 is described as being provided across the extension direction of the extension portion. However, like the second braid 34B, the second braid 34 may cover the outer periphery of the first braid 33 with a portion of the extension portion 23. For example, as shown in FIG. 5 , the second braid 34B includes a first portion 34x and a second portion 34y. The second braid 34B differs from the second braid 34 in that it is provided with a portion of the extension portion 23. The extension portion 23 has the first portion 34x and the second portion 34y provided separately from each other. The first portion 34x covers the outer periphery of the first braid 33 with a portion of the extension portion 23. The second portion 34y is separated from the first portion 34x in the extension direction and covers the outer periphery of the first braid 33 with a portion of the extension portion 23. For example, the first portion 34x covers the outer periphery of the first braid 33 with a part of the first extension portion 23a, and the second portion 34y covers the outer periphery of the first braid 33 with a part of the second extension portion 23b. Between the first portion 34x and the second portion 34y, the first braid 33 is exposed to the outside.

[0057] With this configuration, the worker can attach the second braid 34B to a portion of the first braid 33 that is close to the surrounding components and therefore is at risk of fraying due to contact with the surrounding components. Also, the worker can attach the second braid 34B to a portion of the first braid 33 that is subject to large vibrations and is at risk of fraying due to contact with the surrounding components. By providing the second braid 34B in the portion of the extension portion 23 where fraying of the first braid 33 is at risk, the weight of the bus bar 20 can be made lighter than if the second braid 34B were to cover the first braid 33 throughout the extension direction.

[0058] Furthermore, the above-described configuration makes it easy to keep manufacturing costs low, and the above-described configuration also improves the attachability of the second braid 34.

[0059] In the first modified example, the first portion 34x covers the outer periphery of the first braid 33 with a part of the first extension portion 23a, and the second portion 34y covers the outer periphery of the first braid 33 with a part of the second extension portion 23b. The positions of the first portion 34x and the second portion 34y are not limited as long as the first portion 34x and the second portion 34y are provided apart from each other. For example, the first portion 34x and the second portion 34y may be provided apart from each other in the first extension portion 23a.

[0060] (Second Modification) In the case where the second braid 34 of the bus bar 20 is exposed to the outside, the surface of the second braid 34 may be formed with a curved surface that follows the curved surface RA.

[0061] With this configuration, the air flow around the bus bar 20 becomes more stable during heat dissipation, and the heat dissipation performance of the bus bar 20 can be improved.

[0062] (Third Modification) The second braid 34 may be colored depending on the heat dissipation required for the bus bar 20 .

[0063] According to this configuration, the emissivity of the bus bar 20 is changed by coloring, thereby improving the heat dissipation performance of the bus bar 20. For example, black is preferable.

[0064] Several embodiments and modifications have been described above. However, the embodiments and modifications are not limited to the above examples. For example, multiple embodiments may be realized in combination with each other. The above-described embodiments can be implemented in various other forms, and various additions, omissions, substitutions, and modifications can be made without departing from the spirit and scope of the present disclosure.

[0065] According to the present disclosure, the shielding performance of the bus bar is less likely to deteriorate even with long-term use.

[0066] 20... Busbar 21... First connection portion 22... Second connection portion 23, 23a, 23b, 23c... Extension portion 31... Conductor 32... Insulating coating 99... Busbar main body 33... First braid 34... Second braid 34B... Second braid 34x... First portion 34y... Second portion 41... First main surface 42... Second main surface 43... First side surface 44... Second side surface 51... First corner portion 52... Second corner portion 53... Third corner portion 54... Fourth corner portion 61... First conductor main surface 62... Second conductor main surface 63... First conductor side surface 64... Second conductor side surface 71... First conductor corner portion 72... Second conductor corner portion 73... Third conductor corner portion 74... Fourth conductor corner portion 81... First main surface 82... Second main surface 83... First side surface 84... Second side surface 91... First corner 92... Second corner 93... Third corner 94... Fourth corner V... Vehicle RA... Curved surface RB... Curved conductive surface RC... Curved surface

Claims

1. A busbar including a plate-shaped extension portion, the extension portion including: a conductor; an insulating coating covering the outer periphery of the conductor; a first metal braid covering the outer periphery of the insulating coating; and a second synthetic resin braid provided at least partially in the extension direction of the extension portion and covering the outer periphery of the first braid.

2. The busbar according to claim 1, wherein the conductor has a flat rectangular cross-sectional shape, the first braid covers the outer periphery of the insulating coating so as to surround the entire periphery of the cross-sectional shape, and the second braid covers the outer periphery of the first braid so as to surround the entire periphery of the cross-sectional shape.

3. The busbar according to claim 1 or 2, wherein the braid density of the second braid is greater than the braid density of the first braid.

4. The busbar according to claim 1 or claim 2, wherein the second braid is tubular and deformable in directions that expand and contract the internal space of the second braid, and covers the outer periphery of the first braid when deformed so that the inner periphery of the second braid is pressed against the outer periphery of the first braid.

5. A busbar as claimed in claim 1 or claim 2, wherein the first braid is tubular and is deformable in both directions of expanding and contracting the internal space of the first braid; the second braid is tubular and is deformable in both directions of expanding and contracting the internal space of the second braid; and in a state in which no external force is applied, the rate of return of the second braid when it deforms from a state in which the internal space of the second braid is contracted to a state in which the internal space of the second braid is expanded is greater than the rate of return of the first braid when it deforms from a state in which the internal space of the first braid is contracted to a state in which the internal space of the first braid is expanded.

6. The busbar according to claim 1 or 2, wherein the second braid includes a first portion and a second portion spaced apart from each other, the first portion of the second braid covers the outer periphery of the first braid with part of the extension portion, the second portion of the second braid is spaced apart from the first portion in the extension direction and covers the outer periphery of the first braid with part of the extension portion, and the first braid is exposed to the outside between the first portion and the second portion.

7. A method for manufacturing a busbar, comprising: preparing a busbar body including a conductor and an insulating coating covering the outer periphery of the conductor; passing the busbar body through a first metallic braid while deforming the first braid in a direction that expands the cylindrical internal space of the first braid; after the busbar body has been passed through the first braid, deforming the first braid in a direction that reduces the internal space of the first braid; passing the busbar body and the first braid through a second synthetic resin braid while deforming the second synthetic resin braid in a direction that expands the cylindrical internal space of the second braid; after the busbar body and the first braid have been passed through the second braid, deforming the second braid in a direction that reduces the internal space of the second braid.

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