Electrical connection unit

Abstract

An electrical connection unit according to the present invention comprises a first member, a second member, a first electronic component, a second electronic component, a first bus bar, a metal member, and a first heat conduction member. The first bus bar has a first end, a second end, and an extension section. The extension section has a plate shape and extends along the first member. The metal member is disposed, on the first member, on the side opposite from that of the second member. The first heat conduction member is disposed between the extension section and the metal member in a first direction. The first heat conduction member has an outer shape that is smaller than that of the extension section in a second direction. The first heat conduction member overlaps the extension section at a position closer to the first end than the center of the extension section in the second direction.

Description

Electrical Connection Unit

[0001] This application claims priority from Japanese Patent Application No. 2024-062569, filed on April 9, 2024, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses a junction box mounted on a vehicle, in which a plurality of electronic components are mounted.

[0003] Japanese Patent Application Laid-Open No. 2022-99475

[0004] However, it is expected that the amount of heat generated will increase in the future as the duration of current application and / or the current value of current application in electric vehicles increases, and therefore there is a demand for improved heat dissipation from electrical connection units.

[0005] One embodiment provides an electrical connection unit that can improve heat dissipation.

[0006] In one embodiment, the electrical connection unit includes a first member, a second member, a first electronic component, a second electronic component, a first bus bar, a metal member, and a first thermally conductive member. The second member forms an accommodation space between itself and the first member. The first electronic component is disposed in the accommodation space. The second electronic component is disposed in the accommodation space. The first bus bar has a first end, a second end, and an extension. The first end is electrically connected to the first electronic component. The second end is electrically connected to the second electronic component. The extension is plate-shaped and extends along the first member. The metal member is disposed on the opposite side of the first member from the second member. The metal member includes a plate portion extending along the first member. When the direction in which the first member and the second member face each other is defined as a first direction, the first thermally conductive member is disposed between the extension and the metal member in the first direction. When the extension direction of the extension portion is defined as a second direction, the first thermal conduction member has an outer shape smaller than that of the extension portion in the second direction, and when viewed from the first direction, the first thermal conduction member overlaps with the extension portion at a position biased toward the first end rather than a center of the extension portion in the second direction.

[0007] In one embodiment, the electrical connection unit includes a first member, a second member, a first electronic component, a second electronic component, a first bus bar, a metal member, and a first thermally conductive member. The second member forms an accommodation space between itself and the first member. The first electronic component is disposed in the accommodation space. The second electronic component is disposed in the accommodation space. The first bus bar has a first end, a second end, and an extension. The first end is electrically connected to the first electronic component. The second end is electrically connected to the second electronic component. The extension is plate-shaped and extends along the first member. The metal member is disposed on the opposite side of the first member from the second member. The metal member includes a plate portion extending along the first member. When the direction in which the first member and the second member face each other is defined as a first direction, the first thermally conductive member is disposed between the extension and the metal member in the first direction. When the extension direction of the extension portion is defined as a second direction, the first thermal conduction member has an outer shape that is smaller than half of the extension portion in the second direction. When viewed from the first direction, the first thermal conduction member overlaps with the extension portion between a center of the extension portion in the second direction and the first end portion.

[0008] In one embodiment, the electrical connection unit includes a first electrical connection module, a second electrical connection module, and a metal member. The second electrical connection module has a different electrical function or a different external connection destination from the first electrical connection module. The first electrical connection module includes a first member, a second member, a first electronic component, a second electronic component, a first bus bar, and a first thermally conductive member. The second component forms a first housing space between itself and the first component. The first electronic component is disposed in the first housing space. The second electronic component is disposed in the first housing space. The first thermally conductive member has a first end, a second end, and an extension. The first end is electrically connected to the first electronic component. The second end is electrically connected to the second electronic component. The extension is plate-shaped and extends along the first component. When the direction in which the first member and the second member face each other is defined as a first direction, the first thermal conduction member is disposed between the extension portion and the metal member in the first direction. The second electrical connection module has the third member, a fourth member, a third electronic component, and a second bus bar. The fourth member forms a second accommodating space between itself and the third member. The third electronic component is disposed in the second accommodating space. The second bus bar is electrically connected to the third electronic component. When viewed from the first direction, the metal member overlaps the first electrical connection module and the second electrical connection module.

[0009] According to one embodiment, the heat dissipation performance of the electrical connection unit can be improved.

[0010] Fig. 1 is a perspective view showing an electrical connection unit according to a first embodiment; Fig. 2 is a partial cross-sectional view taken along line II-II of the electrical connection unit shown in Fig. 1; Fig. 3 is a partial cross-sectional view taken along line III-III of the electrical connection unit shown in Fig. 1; Fig. 4 is a partial cross-sectional view showing an electrical connection unit according to a second embodiment;

[0011] First Embodiment A first embodiment will be described below with reference to the drawings. In this disclosure, "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.

[0012] (Electrical Connection Unit) FIG. 1 is a perspective view showing an electrical connection unit 1 according to a first embodiment. The electrical connection unit 1 is a device mounted on an electric vehicle such as an EV (Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a PHEV (Plug-in Hybrid Electric Vehicle). The electrical connection unit 1 is a connection device capable of electrically connecting multiple electrical devices mounted on the electric vehicle. The multiple electrical devices include, but are not limited to, a battery pack, an inverter, a power window (window opening / closing device), and a headlight. The electrical connection unit 1 may also be referred to as an "electrical connection box" or a "junction box." Note that the "electrical connection unit" referred to in this disclosure is not limited to a configuration in which multiple junction boxes 4, as described below, are integrated. The "electrical connection unit" may, for example, only have a configuration corresponding to one junction box 4.

[0013] As shown in Fig. 1 , the electrical connection unit 1 includes, for example, a metal member 2, a plurality of fasteners 3 (see Fig. 2 ), a plurality of junction boxes 4, and an insulating section 5. In this embodiment, the electrical connection unit 1 is mounted on the outside of a battery pack of an electric vehicle. Note that the mounting location of the electrical connection unit 1 is not limited to the above example. The electrical connection unit 1 may be mounted inside the battery pack, near another electrical device, or near a cooling device.

[0014] (Metal Member) The metal member 2 is formed from a metal material and has higher thermal conductivity than the housing 10 of the junction box 4, which will be described later. The metal member 2 is formed from a metal material such as aluminum or an aluminum alloy. In this embodiment, the metal member 2 includes a plate portion 2p extending along the bottom wall 11 of the housing 10 of the junction box 4. The metal member 2 may be formed only from the plate portion 2p, or may have an edge portion standing up from the outer periphery of the plate portion 2p.

[0015] Hereinafter, the direction in which the metal member 2 and the junction box 4 face each other will be referred to as the Z direction (first direction). The direction from the metal member 2 toward the junction box 4 will be referred to as the +Z direction. The direction from the junction box 4 toward the metal member 2 will be referred to as the -Z direction. The directions that intersect with each other within a plane facing the Z direction will be referred to as the X direction and the Y direction. In one example of this embodiment, the X direction, the Y direction, and the Z direction are directions that are perpendicular to each other. In this example, the Z direction is the "up-down direction." In this example, the +Z direction is the upward direction, and the -Z direction is the downward direction. However, the orientation in which the electrical connection unit 1 is mounted is not limited to the above example.

[0016] In this embodiment, the plate portion 2p of the metal member 2 is a plate extending in the X and Y directions. The plate portion 2p of the metal member 2 has a mounting surface (support surface) 2a as one surface facing the +Z direction. The mounting surface 2a is, for example, a flat surface extending along the X and Y directions. A plurality of junction boxes 4 are mounted on the mounting surface 2a via insulating portions 5, which will be described later.

[0017] Furthermore, the metal member 2 is formed slightly larger than the plurality of junction boxes 4 described below when viewed from the Z direction. For example, the outer peripheral edge 2b of the metal member 2 is formed along the outer side of the plurality of junction boxes 4 when viewed from the Z direction. For example, the outer peripheral edge 2b of the metal member 2 is formed along the outer shapes of the plurality of junction boxes 4. The metal member 2 may be provided with an additional heat dissipation structure such as a heat dissipation fin.

[0018] (Fixing Device) FIG. 2 is a partial cross-sectional view of the electrical connection unit 1 shown in FIG. 1 taken along line II-II. As shown in FIG. 2, the fixing device 3 fixes the metal member 2 to an external mounting body 6. The mounting body 6 is, for example, a battery pack on which the electrical connection unit 1 is mounted. Note that the mounting body 6 does not have to be a battery pack and may be, for example, a vehicle body. The fixing device 3 is, for example, a bolt. The fixing device 3 penetrates the metal member 2 from the mounting surface 2a in the -Z direction. The fixing device 3 is provided close to the outer circumferential edge 2b of the metal member 2. When viewed from the Z direction, the fixing device 3 is positioned inside the outer circumferential edge 2b of the metal member 2 and outside the junction box 4, which will be described later. The fixing device 3 is made of, for example, metal. The fixing device 3 transfers heat from the metal member 2 to the mounting body 6.

[0019] (Junction Box) Each of the multiple junction boxes 4 is a connection device capable of electrically connecting multiple electrical devices. The junction box 4 may be referred to as an "electrical connection box." The multiple junction boxes 4 include, for example, a first junction box 4A and a second junction box 4B (see FIG. 1). The first junction box 4A and the second junction box 4B may have different electrical functions. Alternatively / in addition to this, the first junction box 4A and the second junction box 4B may have different external connection destinations (electrical devices connected to them). For example, the first junction box 4A is electrically connected to a first electrical device disposed outside the electrical connection unit 1. The second junction box 4B is electrically connected to a second electrical device disposed outside the electrical connection unit 1. The second electrical device is an electrical device with a different purpose from the first electrical device. The first junction box 4A is an example of a "first electrical connection module." The second junction box 4B is an example of a "second electrical connection module." Hereinafter, when there is no need to distinguish between the first junction box 4A and the second junction box 4B, they will simply be referred to as "junction box 4."

[0020] The multiple junction boxes 4 are arranged facing the metal member 2 in the Z direction. The multiple junction boxes 4 are mounted close to each other on the mounting surface 2a of the metal member 2. The multiple junction boxes 4 may be in contact with each other. The multiple junction boxes 4 are arranged inside the outer peripheral edge 2b of the metal member 2 when viewed from the Z direction.

[0021] (First Junction Box) First, the first junction box 4 A will be described. As shown in Fig. 2, the first junction box 4 A includes, for example, a housing 10, a plurality of electronic components 20, a bus bar 30, and a plurality of heat conduction members 40.

[0022] (Housing) The housing 10 is a member that forms the outer shell of the first junction box 4A. The housing 10 is attached to the mounting surface 2a of the metal member 2, for example, with an insulating portion 5 interposed therebetween. Alternatively, the housing 10 may be attached to the mounting surface 2a of the metal member 2. The housing 10 houses multiple electronic components 20 that generate heat when current is applied. The housing 10 is non-metallic. The housing 10 is formed from an insulating material such as synthetic resin and has insulating properties. The housing 10 of this embodiment is formed from a resin material such as polyprene.

[0023] The housing 10 is formed, for example, in the shape of a rectangular parallelepiped. The housing 10 has, for example, a bottom wall 11, a peripheral wall 12, and an upper wall 13. The bottom wall 11 is a wall that faces the mounting surface 2a of the metal member 2 in the Z direction. The bottom wall 11 extends along the X and Y directions. The bottom wall 11 extends along the mounting surface 2a of the metal member 2. When viewed from the Z direction, the bottom wall 11 protrudes, for example, outside the peripheral wall 12. The bottom wall 11 has a through hole 14 that penetrates the bottom wall 11 in the Z direction. A thermal conduction member 40, which will be described later, is disposed in the through hole 14. One through hole 14 is formed for each electronic component 20.

[0024] The peripheral wall 12 extends in the +Z direction from the bottom wall 11. When viewed from the Z direction, the peripheral wall 12 is located inside the outer peripheral edge 11a of the bottom wall 11. The peripheral wall 12 is formed along the outer peripheral edge 11a of the bottom wall 11. The upper wall 13 is disposed opposite the bottom wall 11 in the Z direction. The upper wall 13 closes the opening of the peripheral wall 12 on the +Z direction side.

[0025] In this embodiment, the housing 10 has a first member 15 and a second member 16. The first member 15 includes, for example, the bottom wall 11 described above. The second member 16 includes, for example, the peripheral wall 12 and the top wall 13 described above. The housing 10 is formed by combining the first member 15 and the second member 16. An accommodation space S1 is formed between the first member 15 and the second member 16, and accommodates multiple electronic components 20. The accommodation space S1 is an example of a "first accommodation space." Alternatively, the first member 15 may include the bottom wall 11 and the peripheral wall 12 described above. The second member 16 may be formed only by the top wall 13. Furthermore, the second member 16 may be formed of an insulating film or the like instead of a wall made of synthetic resin.

[0026] (Electronic Components) Multiple electronic components 20 are accommodated in the accommodation space S1 of the housing 10. In this embodiment, the multiple electronic components 20 include a first electronic component 20A and a second electronic component 20B. The electronic components 20A and 20B are, for example, connectors, fuses, relays (e.g., mechanical relays or semiconductor relays), capacitors, branching components, electronic control units, or electronic component units formed by unitizing two or more of these. Note that the types of the electronic components 20A and 20B are not limited to the above examples. The electronic components 20A and 20B may be the same type of component or different types of components. The electronic components 20A and 20B are, for example, heat-generating components that generate heat when power is applied. Hereinafter, when there is no need to distinguish between the electronic components 20A and 20B, they will be referred to as "electronic components 20."

[0027] In the illustrated example, the first electronic component 20A and the second electronic component 20B are aligned in the X direction. The first electronic component 20A and the second electronic component 20B are arranged, for example, on the surface of the bottom wall 11 exposed to the accommodation space S1. The first electronic component 20A and the second electronic component 20B are arranged along the bottom wall 11. The first electronic component 20A and the second electronic component 20B are fixed to the bottom wall 11, for example. Alternatively, the first electronic component 20A and the second electronic component 20B may be arranged along the peripheral wall 12 or the top wall 13. The first electronic component 20A and the second electronic component 20B may be fixed to the peripheral wall 12 or the top wall 13.

[0028] (Busbar) The busbar 30 is a connecting member that electrically connects the first electronic component 20A and the second electronic component 20B. For example, the entire busbar 30 is housed within the housing 10. The busbar 30 is an example of a "first busbar." For example, the entire busbar is formed in a plate shape. The busbar 30 has, for example, a first end 31, a second end 32, and an extension 33.

[0029] The first end 31 is located at one end of the bus bar 30. For example, the first end 31 protrudes from the extension portion 33 in the +Z direction. For example, the first end 31 is formed by bending one end of the extension portion 33 in the +Z direction. The first end 31 is adjacent to the terminal portion of the first electronic component 20A in the X direction (or Y direction). The first end 31 is connected to the terminal portion of the first electronic component 20A. The first end 31 is electrically and thermally connected to the first electronic component 20A.

[0030] The second end 32 is located at the other end of the bus bar 30. The second end 32 protrudes, for example, from the extension 33 in the +Z direction. The second end 32 is formed, for example, by bending the other end of the extension 33 in the +Z direction. The second end 32 is adjacent to the terminal portion of the second electronic component 20B in the X direction (or Y direction). The second end 32 is connected to the terminal portion of the second electronic component 20B. The second end 32 is electrically and thermally connected to the second electronic component 20B.

[0031] The extension portion 33 is a plate-like portion extending along the bottom wall 11 (first member 15). For example, the extension portion 33 extends between the first end 31 and the second end 32 so as to connect the first end 31 and the second end 32. Note that the extension portion 33 is not limited to a portion extending between the first end 31 and the second end 32. For example, the extension portion 33 may be a branch portion extending from the first end 31 in a direction different from the second end 32. In this embodiment, the extension portion 33 overlaps with the multiple through holes 14 of the bottom wall 11 when viewed from the Z direction.

[0032] In this embodiment, the extension portion 33 extends in the X direction. The X direction is the extension direction of the extension portion 33 and is an example of the "second direction." The extension portion 33 may bend from the X direction to the Y direction and / or from the Y direction to the X direction and extend. In this case, the second direction is the direction along the extension portion 33 while bending.

[0033] (Thermal Conduction Member) The thermal conduction member 40 is a member that conducts heat from the bus bar 30 to the metal member 2. The thermal conduction member 40 is, for example, a member that has higher thermal conductivity than the bottom wall 11. The thermal conduction member 40 is, for example, a metal member, a thermally conductive sheet, a thermally conductive filler, a thermally conductive paste, a thermally conductive rubber, or a combination thereof, but is not limited to the above examples. In this embodiment, the multiple thermal conduction members 40 include a first thermal conduction member 40A and a second thermal conduction member 40B. Hereinafter, when there is no need to distinguish between the first thermal conduction member 40A and the second thermal conduction member 40B, they will be simply referred to as "thermal conduction member 40."

[0034] The heat conduction member 40 is disposed between the extension portion 33 of the bus bar 30 and the metal member 2 in the Z direction. In this embodiment, the heat conduction member 40 is disposed in the through hole 14 of the bottom wall 11 and contacts the extension portion 33 of the bus bar 30. For example, the heat conduction member 40 is embedded without any gaps in the through hole 14 of the bottom wall 11 and is integrated with the housing 10. Alternatively, a gap may exist between the heat conduction member 40 and the inner surface of the through hole 14. One heat conduction member 40 is provided for each through hole 14. That is, one heat conduction member 40 is provided corresponding to each electronic component 20.

[0035] The length L2 of the heat conduction member 40 in the extension direction of the extension portion 33 of the bus bar 30 (the outer shape of the heat conduction member 40) is smaller than the length L1 of the extension direction of the extension portion 33 of the bus bar 30 (the outer shape of the extension portion 33). For example, the length L2 of the heat conduction member 40 in the extension direction of the extension portion 33 of the bus bar 30 (the outer shape of the extension portion 33) is smaller than half the length L1 of the extension direction of the extension portion 33 of the bus bar 30 (the outer shape of the extension portion 33).

[0036] In this embodiment, when viewed from the Z direction, the first thermal conduction member 40A overlaps with the extension portion 33 between the center C in the extension direction of the extension portion 33 and the first end portion 31. The first thermal conduction member 40A is positioned closer to the first end portion 31 than the center C in the extension direction of the extension portion 33. For example, the distance between the first end portion 31 (or the first electronic component 20A) and the first thermal conduction member 40A is smaller than the distance between the center C in the extension direction of the extension portion 33 and the first thermal conduction member 40A. For example, the first thermal conduction member 40A may overlap with the first end portion 31 or the first electronic component 20A when viewed from the Z direction.

[0037] Similarly, when viewed from the Z direction, the second thermal conduction member 40B overlaps with the extension portion 33 between the center C in the extension direction of the extension portion 33 and the second end portion 32. The second thermal conduction member 40B is positioned closer to the second end portion 32 than the center C in the extension direction of the extension portion 33. For example, the distance between the second end portion 32 (or the second electronic component 20B) and the second thermal conduction member 40B is smaller than the distance between the center C in the extension direction of the extension portion 33 and the second thermal conduction member 40B. For example, the second thermal conduction member 40B may overlap with the second end portion 32 or the second electronic component 20B when viewed from the Z direction.

[0038] (Second Junction Box) Next, the second junction box 4B will be described. Figure 3 is a partial cross-sectional view of the electrical connection unit shown in Figure 1 taken along line III-III. The second junction box 4B includes, for example, a housing 50, a plurality of electronic components 60, a bus bar 70, and a plurality of heat conduction members 80.

[0039] The details of the second junction box 4B are the same as those of the first junction box 4A. For example, in the above description of the first junction box 4A, the details of the second junction box 4B can be obtained by replacing "housing 10" with "housing 50," "electronic component 20" with "electronic component 60," "first electronic component 20A" with "third electronic component 60A," "second electronic component 20B" with "fourth electronic component 60B," "bus bar 30" with "bus bar 70," "thermal conduction member 40" with "thermal conduction member 80," "first thermal conduction member 40A" with "third thermal conduction member 80A," and "second thermal conduction member 40B" with "fourth thermal conduction member 80B." Furthermore, the "bottom wall 11," "periphery wall 12," "top wall 13," "first member 15," "second member 16," and "accommodation space S1" of the housing 10 may be read as the "bottom wall 51," "periphery wall 52," "top wall 53," "third member 55," "fourth member 56," and "accommodation space S2" of the housing 50, respectively. The accommodation space S2 is an example of a "second accommodation space." Furthermore, the "first end 31," "second end 32," and "extension 33" of the bus bar 30 may be read as the "first end 71," "second end 72," and "extension 73" of the bus bar 70, respectively. The bus bar 70 is an example of a "second bus bar."

[0040] The first junction box 4A and the second junction box 4B may or may not be electrically connected to each other. The storage space S1 and the storage space S2 are, for example, separated from each other.

[0041] In this embodiment, the metal member 2 is located on the opposite side (-Z direction side) from the second member 16 with respect to the first member 15 of the housing 10. Similarly, the metal member 2 is located on the opposite side (-Z direction side) from the fourth member 56 with respect to the third member 55 of the housing 50. When viewed from the Z direction, the metal member 2 overlaps with the first junction box 4A and the second junction box 4B.

[0042] (Insulating portion) The insulating portion 5 is disposed between the electronic components 20, 60 and the metal member 2, and insulates the electronic components 20, 60 from the metal member 2. The insulating portion 5 is also disposed between the bus bars 30, 70 and the metal member 2, and insulates the bus bars 30, 70 from the metal member 2. The insulating portion 5 is also disposed between the heat conducting members 40, 80 and the metal member 2, and insulates the heat conducting members 40, 80 from the metal member 2.

[0043] The insulating portion 5 is disposed, for example, between the bottom wall 11, 51 of the housing 10, 50 and the metal member 2. The insulating portion 5 is in close contact with the metal member 2, the bottom wall 11, 51, and the heat conduction member 40, 80 without any gaps. The insulating portion 5 is an insulating sheet extending along the X and Y directions. When viewed from the Z direction, the insulating portion 5 is formed to have the same shape and size as the bottom wall 11, 51 of the housing 10, 50. The insulating portion 5 covers the entire bottom wall 11, 51 of the housing 10, 50 from the -Z direction. The insulating portion 5 is interposed, for example, between the heat conduction member 40, 80 and the metal member 2, and is in close contact with the heat conduction member 40, 80 and the metal member 2, respectively.

[0044] The insulating portion 5 may be provided inside the housing 10, 50 instead of being disposed between the metal member 2 and the bottom wall 11, 51 of the housing 10, 50. For example, the insulating portion 5 may be provided between the bottom wall 11, 51 of the housing 10, 50 and the bus bar 30, 70.

[0045] (Operation) The first junction box 4A includes a heat conductive member 40 disposed between the extension 33 of the bus bar 30 and the metal member 2 in the Z direction. Therefore, a portion of the heat generated by the first electronic component 20A in the first junction box 4A is conducted to the extension 33 of the bus bar 30. A portion of the heat conducted from the first electronic component 20A to the extension 33 of the bus bar 30 is conducted to the metal member 2 outside the housing 10 through the first heat conductive member 40A. The heat conducted to the metal member 2 is dissipated to the outside of the housing 10. Similarly, a portion of the heat generated by the second electronic component 20B in the first junction box 4A is conducted to the extension 33 of the bus bar 30. A portion of the heat conducted from the second electronic component 20B to the extension 33 of the bus bar 30 is conducted to the metal member 2 outside the housing 10 through the second heat conductive member 40B. The heat conducted to the metal member 2 is dissipated to the outside of the housing 10. This heat flow also occurs in the second junction box 4B.

[0046] (Advantages) As a comparative example, consider a junction box 4 that does not have a heat conduction member 40. In the configuration of this comparative example, heat generated by the electronic components 20 when power is applied is transferred from the electronic components 20 to the bus bar 30 and dissipated from the bus bar 30 into the air within the housing 10.

[0047] Incidentally, it is expected that the energization time and / or energization current value in electric vehicles will increase in the future due to factors such as an extension of the driving distance of electric vehicles or a reduction in charging time. When the energization time and / or energization current value increases, the amount of heat generated in the junction box 4 increases. In this case, there is a possibility that the temperature rise in the electronic components 20 will be large if the heat is only dissipated from the bus bar 30 into the air within the housing 10.

[0048] Therefore, in this embodiment, the electrical connection unit 1 includes a first member 15, a second member 16, a first electronic component 20A, a second electronic component 20B, a bus bar 30, a metal member 2, and a first thermal conduction member 40A. The second member 16 forms an accommodation space S1 between itself and the first member 15. The first electronic component 20A is disposed in the accommodation space S1. The second electronic component 20B is disposed in the accommodation space S1. The bus bar 30 has a first end 31, a second end 32, and an extension 33. The first end 31 is electrically connected to the first electronic component 20A. The second end 32 is electrically connected to the second electronic component 20B. The extension 33 is plate-shaped and extends along the first member 15. The metal member 2 is disposed on the opposite side of the first member 15 from the second member 16. The metal member 2 includes a plate portion 2p extending along the first member 15. When the direction in which first member 15 and second member 16 face each other is defined as a first direction, first heat conduction member 40A is disposed between extension portion 33 and metal member 2 in the first direction. When the extension direction of extension portion 33 is defined as a second direction, first heat conduction member 40A has a smaller outer shape in the second direction than extension portion 33. When viewed from the first direction, first heat conduction member 40A overlaps extension portion 33 at a position biased toward first end portion 31 rather than the center C of extension portion 33 in the second direction.

[0049] With this configuration, for example, a portion of the heat generated by the first electronic component 20A can be transferred to the metal member 2 by the first thermal conduction member 40A and dissipated through the metal member 2. This improves the heat dissipation performance of the electrical connection unit 1.

[0050] Here, for example, when the temperature of the electrical connection unit 1 rises, a difference in the amount of thermal expansion between the first member 15 and the metal member 2 may occur due to a difference in the linear expansion coefficient between the first member 15 and the metal member 2. When a difference in the amount of expansion between the first member 15 and the metal member 2 occurs, a shear force in the X direction or the Y direction may act between the first member 15 and the metal member 2.

[0051] However, according to the above-described configuration of the present embodiment, the first thermal conduction member 40A has an outer diameter smaller than the extension 33 of the bus bar 30 in the second direction. Therefore, even when a shear force acts between the first member 15 and the metal member 2, the load acting on the first thermal conduction member 40A is smaller than when a thermal conduction member larger than the entire length of the bus bar 30 is disposed, thereby extending the product life of the electrical connection unit 1. Meanwhile, in the present embodiment, when viewed from the first direction, the first thermal conduction member 40A overlaps with the extension 33 of the bus bar 30 at a position closer to the first end 31 than the center C of the extension 33 in the second direction. That is, the first thermal conduction member 40A overlaps with the extension 33 of the bus bar 30 relatively close to the first electronic component 20A. Therefore, even when the small first thermal conduction member 40A described above is provided, heat generated in the first electronic component 20A can be efficiently dissipated to the metal member 2. This improves the heat dissipation performance of the electrical connection unit 1.

[0052] From another perspective, the first thermal conduction member 40A has an outer diameter smaller than half the extension 33 of the bus bar 30 in the second direction. Therefore, even when a shear force acts between the first member 15 and the metal member 2, the load acting on the first thermal conduction member 40A is smaller than when a thermal conduction member larger than the entire length of the bus bar 30 is disposed, thereby extending the product life of the electrical connection unit 1. Meanwhile, when viewed from the first direction, the first thermal conduction member 40A overlaps with the extension 33 of the bus bar 30 between the center C and the first end 31 of the extension 33 in the second direction. That is, the first thermal conduction member 40A overlaps with the extension 33 of the bus bar 30 relatively close to the first electronic component 20A. Therefore, even when the small first thermal conduction member 40A described above is provided, heat generated in the first electronic component 20A can be efficiently dissipated to the metal member 2. This improves the heat dissipation performance of the electrical connection unit 1.

[0053] In this embodiment, the first electronic component 20A and the second electronic component 20B are arranged along the first member 15. This configuration makes it easier to arrange the extension portion 33 of the bus bar 30 along the first member 15. This allows for further improvement in the heat dissipation performance of the electrical connection unit 1.

[0054] In this embodiment, the second thermal conduction member 40B is disposed between the extension portion 33 of the bus bar 30 and the metal member 2 in the first direction. The second thermal conduction member 40B has an outer shape smaller than that of the extension portion 33 of the bus bar 30 in the second direction. The second thermal conduction member 40B is disposed away from the first thermal conduction member 40A. The second thermal conduction member 40B overlaps with the extension portion 33 of the bus bar 30 between the center C of the extension portion 33 in the second direction and the second end 32. With this configuration, even when a shear force acts between the first member 15 and the metal member 2, the load acting on the second thermal conduction member 40B is smaller than when a thermal conduction member larger than the entire length of the bus bar 30 is disposed, thereby extending the product life of the electrical connection unit 1. Meanwhile, in this embodiment, the second thermal conduction member 40B overlaps with the extension portion 33 of the bus bar 30 between the center C of the extension portion 33 in the second direction and the second end 32. That is, the second heat conducting member 40B overlaps the extension 33 of the bus bar 30 relatively close to the second electronic component 20B. Therefore, even when a small second heat conducting member 40B is provided as described above, the heat generated in the second electronic component 20B can be efficiently dissipated to the metal member 2. This further improves the heat dissipation performance of the electrical connection unit 1.

[0055] In this embodiment, the first member 15 has a through hole 14 that penetrates the first member 15 in a first direction. The first heat conduction member 40A is disposed in the through hole 14. With this configuration, the first heat conduction member 40A makes it easier to conduct heat from the bus bar 30 to the metal member 2. This further improves the heat dissipation performance of the electrical connection unit 1.

[0056] For example, if there is a gap between first heat conduction member 40A and the inner circumferential surface of through hole 14, the shear force is less likely to act on first heat conduction member 40A. For example, if first heat conduction member 40A is made of a material with a higher elastic modulus than first member 15 (a material that is easily elastically deformed), the shear force is less likely to act on first heat conduction member 40A.

[0057] In this embodiment, the electrical connection unit 1 includes a first junction box 4A and a second junction box 4B. The second junction box 4B differs from the first junction box 4A in at least one of electrical function and external connection destination. The first junction box 4A includes a first member 15, a second member 16, a first electronic component 20A, a second electronic component 20B, a bus bar 30, and a first thermal conduction member 40A. The second junction box 4B includes a third member 55, a fourth member 56, a third electronic component 60A, and a bus bar 70. The fourth member 56 forms an accommodation space S2 with the third member 55. The third electronic component 60A is disposed between the third member 55 and the fourth member 56. The bus bar 70 is electrically connected to the third electronic component 60A. When viewed from the first direction, the metal member 2 overlaps the first junction box 4A and the second junction box 4B. With this configuration, the metal member 2 having a large heat dissipation area that overlaps with multiple junction boxes 4 can be used to dissipate heat that is transferred from the first electronic component 20A of the first junction box 4A to the metal member 2 via the first thermal conductive member 40A. This can further improve the heat dissipation performance of the electrical connection unit 1.

[0058] Furthermore, with the above configuration, the first junction box 4A and the second junction box 4B can be easily supported by a single metal member 2. This makes it easier to handle the first junction box 4A and the second junction box 4B as a single unit.

[0059] In this embodiment, the bus bar 70 of the second junction box 4B includes a plate-shaped extension portion 73 that extends along the third member 55. The second junction box 4B further includes a third heat conduction member 80A that is disposed between the extension portion 73 of the bus bar 70 and the metal member 2 in the first direction. With this configuration, the third heat conduction member 80A can conduct a portion of the heat generated by the third electronic component 60A from the extension portion 73 of the bus bar 70 to the metal member 2. This can further improve the heat dissipation performance of the electrical connection unit 1.

[0060] In this embodiment, the metal member 2 is formed in a plate shape extending in a direction intersecting the Z direction. Such a plate shape of the metal member 2 prevents the electrical connection unit 1 from becoming too large in the Z direction, while allowing the metal member 2 to effectively dissipate heat to the outside of the housing 10. In addition, the mountability of the electrical connection unit 1 is improved.

[0061] In the present embodiment, the first heat conducting member 40A is in contact with the extension portion 33 of the bus bar 30. By the first heat conducting member 40A being in contact with the extension portion 33 of the bus bar 30, heat is more easily transferred from the first heat conducting member 40A to the metal member 2.

[0062] In this embodiment, the electrical connection unit 1 includes an insulating portion 5 disposed between the metal member 2 and the electronic component 20. The insulating portion 5 insulates the metal member 2 from the electronic component 20. The insulating portion 5 enables the electrical connection unit 1 to suppress current leakage from the electronic component 20 to the metal member 2.

[0063] Second Embodiment A second embodiment will be described below with reference to the drawings. The same names and symbols are used for components of the second embodiment that are common to the first embodiment, and descriptions thereof will be omitted as appropriate. Note that components other than those described below are the same as those of the first embodiment.

[0064] 4 is a partial cross-sectional view showing the electrical connection unit 1 of the second embodiment. The electrical connection unit 1 of the second embodiment further includes a cooling mechanism 7 and a heat conduction member 8 in addition to the configuration described above in the first embodiment.

[0065] (Cooling mechanism) The cooling mechanism 7 is a mechanism that promotes heat dissipation from the metal member 2. The cooling mechanism 7 is stacked in the Z direction on the metal member 2. The cooling mechanism 7 is attached to the surface of the metal member 2 opposite to the mounting surface 2a. The cooling mechanism 7 cools the metal member 2. An example of the cooling mechanism 7 is a water-cooled plate attached to the vehicle body. The cooling mechanism 7 is attached to an attachment body 6 such as a battery pack.

[0066] In this embodiment, the plate portion 2p of the metal member 2 has a fixing portion 2f that is attached to the cooling mechanism 7. The fixing portion 2f of the metal member 2 has a mounting hole 2h to which a fixing device 3 is attached. The fixing device 3 is, for example, passed through the mounting hole 2h of the metal member 2 and engaged with the cooling mechanism 7. The fixing device 3 is, for example, a bolt.

[0067] (Thermal Conduction Member) The thermal conduction member 8 is disposed between the metal member 2 and the cooling mechanism 7. The thermal conduction member 8 is thermally connected to the metal member 2 and the cooling mechanism 7. The thermal conduction member 8 transfers heat from the metal member 2 to the cooling mechanism 7. The thermal conduction member 8 is, for example, a thermally conductive insulating material such as a thermally conductive sheet, a thermally conductive paste (grease), or a thermally conductive rubber. The thermal conduction member 8 is disposed on the surface of the metal member 2 opposite the mounting surface 2a in the Z direction. The thermal conduction member 8 is, for example, compressed in the Z direction by the metal member 2 and the cooling mechanism 7, thereby tightly adhering the metal member 2 and the cooling mechanism 7. The thermal conduction member 8 is formed to have the same shape and size as the bottom wall 11 of the housing 10 when viewed from the Z direction. The thermal conduction member 8 overlaps the entire thermal conduction member 40 and the entire insulating portion 5 in the Z direction.

[0068] (Advantages) In this embodiment, the electrical connection unit 1 further includes a cooling mechanism 7 that cools the metal member 2, and a heat conduction member 8 that is disposed between the metal member 2 and the cooling mechanism 7 and is thermally connected to the metal member 2 and the cooling mechanism 7. The electrical connection unit 1 can transfer heat conducted to the metal member 2 to the cooling mechanism 7 via the heat conduction member 8. This can further improve the heat dissipation performance of the electrical connection unit 1.

[0069] <Other Modifications> In the examples of the above-described embodiments, the X direction, Y direction, and Z direction are directions that are orthogonal to one another. Note that the X direction, Y direction, and Z direction only need to intersect with one another and do not have to be orthogonal to one another. Also, although the Z direction is described as the "vertical direction," the Z direction does not have to be the "vertical direction." For example, the Z direction may be a direction that is inclined with respect to the "vertical direction," or may be the "horizontal direction." Also, although the +Z direction is described as the upward direction and the -Z direction is described as the downward direction, the +Z direction may be the downward direction and the -Z direction may be the upward direction.

[0070] The heat conduction member 40 may be an insulating material having thermal conductivity, such as a heat conduction sheet, a heat conduction paste (grease), or a heat conduction rubber. In this case, the heat conduction member 40 suppresses current leakage from the electronic component 20 to the metal member 2, making the insulating portion 5 unnecessary. In this case, the heat conduction member 40 is in direct contact with both the metal member 2 and the bus bar 30.

[0071] Furthermore, the bus bar 30 may be drawn out to the outside of the housing 10 and thermally connected to the heat conduction member 40 outside the housing 10. The bus bar 30 drawn out to the outside of the housing 10 may not be directly connected to the electronic component 20, but may be connected to, for example, an input / output unit of the junction box 4.

[0072] In the above-described embodiments, the cooling mechanism 7 is, for example, a water-cooled plate attached to the vehicle body. However, the cooling mechanism 7 may be a separate member having a heat dissipation structure such as heat dissipation fins, or a liquid-cooled cooling mechanism 7 other than water.

[0073] In each of the above-described embodiments, when viewed from the first direction, the metal member 2 has a large heat dissipation area that overlaps with the first junction box 4A and the second junction box 4B, thereby improving the heat dissipation performance of the electrical connection unit 1. From this perspective, it is not essential that the outer shape of the heat conduction member 40 in the second direction be smaller than that of the extension portion 33. It is also not essential that the heat conduction member 40 overlaps with the extension portion 33 at a position that is biased toward the first end 31 rather than the center of the extension portion 33 in the second direction.

[0074] According to the present disclosure, it is possible to improve the heat dissipation performance of the electrical connection unit.

[0075] REFERENCE SIGNS LIST 1 Electrical connection unit 2 Metal member 2a Mounting surface 2b Outer periphery 2p Plate portion 2f Fixing portion 3 Fixing tool 4 Junction box (electrical connection module) 4A First junction box (first electrical connection module) 4B Second junction box (second electrical connection module) 5 Insulating portion 6 Mounting body 7 Cooling mechanism 8 Heat conducting member 10 Housing 11 Bottom wall 11a Outer periphery 12 Peripheral wall 13 Top wall 14 Through hole 15 First member 16 Second member 20 Electronic component 20A First electronic component 20B Second electronic component 30 Bus bar (first bus bar) 31 First end 32 Second end 33 Extension portion 40 Heat conducting member 40A First heat conducting member 40B Second heat conducting member 50 Housing 51 Bottom wall 51a Outer periphery 52 Peripheral wall 53 Upper wall 54 Through hole 55 Third member 56 Fourth member 60 Electronic component 60A Third electronic component 60B Fourth electronic component 70 Bus bar (second bus bar) 71 First end 72 Second end 73 Extension portion 80 Heat conduction member 80A Third heat conduction member 80B Fourth heat conduction member

Claims

1. An electrical connection unit comprising: a first member; a second member forming a storage space between itself and the first member; a first electronic component disposed in the storage space; a second electronic component disposed in the storage space; a first bus bar including a first end electrically connected to the first electronic component, a second end electrically connected to the second electronic component, and a plate-shaped extension portion extending along the first member; a metal member disposed on the opposite side of the first member from the second member and including a plate portion extending along the first member; and a first heat conduction member, wherein a first direction is a direction in which the first member and the second member face each other and a second direction is a direction in which the extension portion extends, the first heat conduction member being disposed between the extension portion and the metal member in the first direction, having a smaller outer shape than the extension portion in the second direction, and overlapping with the extension portion at a position biased closer to the first end than to the center of the extension portion in the second direction when viewed from the first direction.

2. The electrical connection unit according to claim 1, wherein the first electronic component and the second electronic component are arranged along the first member.

3. An electrical connection unit as described in claim 1 or claim 2, further comprising a second heat conduction member that is arranged between the extension portion and the metal member in the first direction, has a smaller outer shape than the extension portion in the second direction, is spaced apart from the first heat conduction member, and overlaps with the extension portion between the center of the extension portion in the second direction and the second end portion.

4. An electrical connection unit as described in claim 1 or claim 2, wherein the first member has a through hole passing through the first member in the first direction, and the first heat conduction member is disposed in the through hole.

5. The electrical connection unit according to claim 1 or 2, wherein the metal member has a fixing portion that is attached to a cooling mechanism.

6. An electrical connection unit as described in claim 1 or claim 2, comprising: a first electrical connection module; and a second electrical connection module that differs from the first electrical connection module in at least one of electrical function and external connection destination, wherein the first electrical connection module includes the first member, the second member, the first electronic component, the second electronic component, the first bus bar, and the first thermal conduction member, wherein the second electrical connection module includes a third member, a fourth member that forms an accommodation space between itself and the third member, a third electronic component disposed between the third member and the fourth member, and a second bus bar that is electrically connected to the third electronic component, and wherein the metal member overlaps with the first electrical connection module and the second electrical connection module when viewed from the first direction.

7. The electrical connection unit according to claim 6, wherein the second bus bar includes a plate-shaped extension extending along the third member, and the second electrical connection module further includes a third heat conduction member disposed between the extension of the second bus bar and the metal member in the first direction.

8. An electrical connection unit comprising: a first member; a second member forming an accommodation space between itself and the first member; a first electronic component arranged in the accommodation space; a second electronic component arranged in the accommodation space; a first bus bar including a first end electrically connected to the first electronic component, a second end electrically connected to the second electronic component, and a plate-like extension portion extending along the first member; a metal member arranged on the opposite side of the first member from the second member and including a plate portion extending along the first member; and when a first direction is a direction in which the first member and the second member face each other and a second direction is an extension direction of the extension portion, a first heat conduction member is arranged between the extension portion and the metal member in the first direction, has an outer shape smaller than half of the extension portion in the second direction, and overlaps with the extension portion between the center of the extension portion in the second direction and the first end.

9. A device comprising: a first electrical connection module; a second electrical connection module different from the first electrical connection module in at least one of an electrical function and an external connection destination; and a metal member; wherein the first electrical connection module comprises: a first member; a second member forming a first housing space between itself and the first member; a first electronic component disposed in the first housing space; a second electronic component disposed in the first housing space; a first bus bar including a first end electrically connected to the first electronic component, a second end electrically connected to the second electronic component, and a plate-shaped extension portion extending along the first member; and, when a first direction is defined as a direction in which the first component and the second component face each other, a first thermal conduction member disposed between the extension portion and the metal member in the first direction; and wherein the second electrical connection module comprises: a third member; a fourth member forming a second housing space between itself and the third member; a third electronic component disposed in the second housing space; and a second bus bar electrically connected to the third electronic component. the metal member overlaps the first electrical connection module and the second electrical connection module when viewed from the first direction.

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