Electrical connection unit

Abstract

To provide an electrical connection unit that can reduce its height.SOLUTION: An electrical connection unit of an embodiment comprises: a first electronic component; a base member that includes a plate-like or sheet-like plane part having a first surface facing the first electronic component and a second surface located on the opposite side of the first surface, wherein when a thickness direction of the plane part is defined as a first direction, the plane part has a first storage part that is recessed in the first direction or penetrates the plane part in the first direction; a bus bar that is electrically connected to the first electronic component, and that includes a plate part stored in the first storage part and extending along the first surface, wherein the plate part includes an exposed part exposed to the outside of the base member on the second surface; a metal plate that has a gap from the plane part and faces the second surface of the plane part; and a heat transfer member that is arranged between the exposed part of the bus bar and the metal plate. A contact surface between the heat transfer member and the exposed part is closer to the metal plate than the second surface in the first direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to an electrical connection unit. [Background technology]

[0002] 2. Description of the Related Art An electrical connection unit is known that has a housing that houses electronic components and a bus bar attached to the housing in an upright position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2024-037492 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, electrical connection units are expected to become even thinner.

[0005] One embodiment provides an electrical connection unit that can be made low-profile. [Means for solving the problem]

[0006] In one embodiment, the electrical connection unit includes a first electronic component, a base member, a bus bar, a metal plate, and a heat transfer member. The base member includes a plate- or sheet-like planar portion having a first surface facing the first electronic component and a second surface located opposite the first surface. When the thickness direction of the planar portion is defined as a first direction, the planar portion has a first housing portion recessed in the first direction or penetrating the planar portion in the first direction. The bus bar is electrically connected to the first electronic component. The bus bar includes a plate portion housed in the first housing portion and extending along the first surface. The plate portion includes an exposed portion exposed to the outside of the base member on the second surface side. The metal plate has a gap between it and the planar portion and faces the second surface of the planar portion. The heat transfer member is disposed between the exposed portion of the bus bar and the metal plate. A contact surface between the heat transfer member and the exposed portion is closer to the metal plate in the first direction than the second surface. [Effects of the Invention]

[0007] According to one embodiment, the electrical connection unit can be made low-profile. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view showing the electrical connection unit of the first embodiment. [Figure 2] FIG. 2 is a perspective view illustrating a main body of the first embodiment. [Figure 3] FIG. 2 is a perspective view illustrating a subunit according to the first embodiment. [Figure 4] FIG. 2 is a partially exploded perspective view of the subunit of the first embodiment. [Figure 5] FIG. 2 is a perspective view illustrating an electronic component and a connecting component according to the first embodiment. [Figure 6] FIG. 2 is a perspective view illustrating an electronic component and a connecting component according to the first embodiment. [Figure 7] FIG. 2 is a perspective view showing a connecting part according to the first embodiment. [Figure 8] FIG. 2 is a perspective view showing the wiring board of the first embodiment. [Figure 9] FIG. 2 is a partially exploded perspective view of the wiring board according to the first embodiment. [Figure 10] FIG. 2 is a plan view showing the wiring board of the first embodiment. [Figure 11] FIG. 2 is a partially exploded perspective view of the connection unit according to the first embodiment. [Figure 12] FIG. 2 is a bottom view showing the wiring board of the first embodiment. [Figure 13] 11 is a cross-sectional view of the structure shown in FIG. 10 taken along line F13-F13. [Figure 14] 11 is a cross-sectional view of the structure shown in FIG. 10 taken along line F14-F14. [Figure 15] 1 is a perspective view showing a three-dimensional bus bar wiring structure according to a first embodiment; [Figure 16] FIG. 2 is a plan view showing the three-dimensional busbar wiring structure of the first embodiment. [Figure 17] FIG. 10 is a cross-sectional view showing an electrical connection unit of a comparative example. [Figure 18] FIG. 10 is a perspective view illustrating an insulating rib according to a second embodiment. [Figure 19] 18 is a cross-sectional view of the structure shown in FIG. 17 taken along line F18-F18. [Figure 20] FIG. 10 is a cross-sectional view illustrating an insulating wall according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the following description, components having the same or similar functions will be assigned the same reference numerals. Duplicate descriptions of those components may be omitted. Note that the configurations described below do not limit the scope of the embodiments.

[0010] In this disclosure, terms are defined as follows: "Connection" is not limited to mechanical connection and may include electrical connection. In other words, "connection" is not limited to direct connection between two elements to be connected, but may include connection between two elements via another element interposed therebetween. "Containment" is not limited to containment of the entire component, but may include containment of only a portion of the component (with the remaining portion of the component protruding). "Facing" means that virtual projections of two objects overlap when viewed from a specific direction. In other words, "facing" is not limited to two objects directly facing each other, but may include cases where two objects face each other with another component interposed between them. "Parallel," "orthogonal," or "same" may include "approximately parallel," "approximately perpendicular," or "approximately the same," respectively.

[0011] In the present disclosure, the +X direction, the −X direction, the +Y direction, the −Y direction, the +Z direction, and the −Z direction are defined as follows: The +X direction is the direction from the first end 80e1 to the second end 80e2 of the metal plate 80 (described later) (see FIG. 11). The −X direction is the direction opposite to the +X direction. Hereinafter, when there is no need to distinguish between the +X direction and the −X direction, they will simply be referred to as the “X direction.” The +Y direction and the −Y direction are directions that intersect (e.g., are perpendicular to) the X direction. The +Y direction is the direction from the third end 80e3 to the fourth end 80e4 of the metal plate 80 (described later) (see FIG. 11). The −Y direction is the direction opposite to the +Y direction. Hereinafter, when there is no need to distinguish between the +Y direction and the −Y direction, they will simply be referred to as the “Y direction.” The +Z direction and the −Z direction are directions that intersect (e.g., are perpendicular to) the X direction and the Y direction. The +Z direction is the direction from the metal plate 80 described later toward the main body portion MU (see FIG. 1). The -Z direction is the direction opposite to the +Z direction. Hereinafter, when there is no need to distinguish between the +Z direction and the -Z direction, they will simply be referred to as the "Z direction." The Z direction is an example of the "first direction." The X direction is an example of the "second direction." Note that the "second direction" is not limited to the X direction, but may be the Y direction or another direction.

[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 "up" and the -Z direction side may be referred to as "down." However, these expressions are used for the convenience of explanation and do not limit the direction of gravity of the electrical connection unit 1 (the installation posture of the electrical connection unit 1).

[0013] (First embodiment) <1. Configuration of the electrical connection unit> FIG. 1 is a cross-sectional view showing an electrical connection unit 1 of a first embodiment. The electrical connection unit 1 is an in-vehicle device mounted on a vehicle such as an EV (Electric Vehicle), HEV (Hybrid Electric Vehicle), or PHEV (Plug-in Hybrid Electric Vehicle). The electrical connection unit 1 may also be referred to as an "electrical connection box" or a "junction box," for example. However, the electrical connection unit 1 is not limited to a box-shaped device.

[0014] The electrical connection unit 1 includes, for example, a main body MU, a metal plate 80, an insulating sheet 91 (see FIG. 11), a plurality of heat transfer members 92, and an insulating cover 93.

[0015] <2. Main body> First, the main body MU will be described. FIG. 2 is a perspective view illustrating the main body unit MU. The main body unit MU is a part that performs the main function of the electrical connection unit 1 (for example, switching the electrical connection state or overcurrent protection). In this embodiment, the main body unit MU is divided into multiple subunits SU. The main body unit MU is formed by connecting multiple subunits SU. In this embodiment, the main body unit MU has three subunits SU (SUX, SUY, SUZ). Each subunit SU may be referred to as a "circuit assembly."

[0016] The subunit SUX has a first electrical function. The subunit SUX includes, for example, a plurality of electronic components 10X and a first wiring board 40X. The plurality of electronic components 10X are electrically connected to the first wiring board 40X.

[0017] The subunit SUY has a second electrical function. The second function is different from the first function. The subunit SUY includes, for example, a plurality of electronic components 10Y and a second wiring board 40Y. The plurality of electronic components 10Y are electrically connected to the second wiring board 40Y.

[0018] The subunit SUZ has a third electrical function. The third function is different from the first and second functions. The subunit SUZ includes, for example, a plurality of electronic components 10Z and a third wiring board 40Z. The plurality of electronic components 10Z are electrically connected to the third wiring board 40Z.

[0019] In this embodiment, the three subunits SUX, SUY, and SUZ are arranged side by side in the X direction. For example, the subunit SUX is arranged on the +X direction side of the subunit SUY. The subunits SUX and SUY are electrically connected via a plurality of coupling bus bars 75 that extend between the first routing board 40X and the second routing board 40Y. On the other hand, the subunit SUZ is arranged on the -X direction side of the subunit SUY. The subunits SUZ and SUY are electrically connected via a plurality of coupling bus bars 75 (only one is shown in FIG. 2 ) that extend between the third routing board 40Z and the second routing board 40Y. The coupling bus bar 75 is arranged on the opposite side of the metal plate 80 from the plurality of subunits SU.

[0020] In this embodiment, the three wiring boards 40X, 40Y, and 40Z included in the three subunits SUX, SUY, and SUZ are arranged on the same plane. In other words, the three wiring boards 40X, 40Y, and 40Z are arranged at the same height in the Z direction. As a result, the three wiring boards 40X, 40Y, and 40Z form one large wiring board 40M.

[0021] In this embodiment, the three subunits SUX, SUY, and SUZ have the same or similar basic structures. Therefore, the following detailed description will focus on one subunit SU. Hereinafter, when there is no need to distinguish between subunits SUX, SUY, and SUZ, they will simply be referred to as "subunits SU." Furthermore, when there is no need to distinguish between electronic component 10X, electronic component 10Y, and electronic component 10Z, they will simply be referred to as "electronic component 10." Furthermore, when there is no need to distinguish between first routing board 40X, second routing board 40Y, and third routing board 40Z, they will simply be referred to as "routing board 40." One subunit SU included in the three subunits SUX, SUY, and SUZ is an example of a "first subunit." Meanwhile, another subunit SU included in the three subunits SUX, SUY, and SUZ is an example of a "second subunit."

[0022] Note that, instead of the above example, the main body MU does not have to be divided into multiple subunits SU. That is, the main body MU may be formed by multiple electronic components 10 and one wiring board 40. Furthermore, the two or more subunits SU are not limited to subunits SU having different functions, and may be subunits SU having the same function.

[0023] <3. Subunit structure> Next, the configuration of the subunit SU will be described. Fig. 3 is a perspective view illustrating the subunit SU. Fig. 4 is a perspective view showing the subunit SU partially exploded. The subunit SU includes, for example, a plurality of electronic components 10, a plurality of connection components 20 for component connection, a plurality of connection components 30 for external connection, and a wiring board 40. The connection components 20 and 30 are members that form a vertical current path. The connection components 20 and 30 may also be referred to as "vertical wiring members."

[0024] <3.1 Electronic components and connecting parts> First, the electronic component 10 and the connecting component 20 for connecting the components will be described. The electronic component 10 is an electronic component that is installed in the subunit SU according to the functions required. The electronic component 10 is, for example, a connector, a fuse, a relay (e.g., a mechanical relay or a semiconductor relay), a capacitor, a branching component, various sensors (e.g., a current sensor or a voltage sensor), an electronic control unit, or an electronic component unit that combines two or more of these. Note that the type of electronic component 10 is not limited to the above example. The electronic component 10 is, for example, a heat-generating component that generates heat when power is applied. Below, a first type electronic component 10M and a second type electronic component 10N will be described as examples of the electronic component 10.

[0025] The connection component 20 is a component that electrically connects the electronic component 10 and the wiring board 40. The connection component 20 forms part of the current path in the subunit SU. The connection component 20 is made of metal (for example, copper or a copper alloy). The connection component 20 may also be referred to as a "metal component." Below, a first type connection component 20M and a second type connection component 20N will be described as examples of the connection component 20.

[0026] <3.1.1 Type 1 Electronic Components> 5 is a perspective view showing a first type electronic component 10M and a first type connecting component 20M. The first type electronic component 10M is an electronic component having a plurality of terminals 13 arranged side by side at one end of the electronic component 10M. The electronic component 10M has, for example, a case 11, a component main body 12, a plurality of terminals 13, and a plurality of mounting portions 14.

[0027] (case) Case 11 is an outer shell member that forms most of the outer shape of electronic component 10M. Case 11 is made of, for example, synthetic resin and has insulating properties. Case 11 houses component main body 12. Note that case 11 and component main body 12 may be formed integrally.

[0028] In this embodiment, the case 11 has an insulating rib 11a that protrudes in a horizontal direction (e.g., the X direction) and extends in the Z direction. The insulating rib 11a is, for example, plate-shaped and extends along the horizontal direction (e.g., the X direction) and the Z direction. The insulating rib 11a extends, for example, over the entire length of the case 11 in the Z direction. The insulating rib 11a is disposed between a plurality of terminals 13 (terminals 13A and 13B described below). The insulating rib 11a electrically insulates the terminals 13A from the terminals 13B. In this embodiment, a portion of the insulating rib 11a is disposed between first portions 21 (described below) of two connection parts 20M connected to the electronic component 10M. The insulating rib 11a electrically insulates the first portions 21 of the two connection parts 20M connected to the electronic component 10M.

[0029] (Component body) The component body 12 is a part that performs the main function of the electronic component 10M. For example, if the electronic component 10M is a relay, the component body 12 includes a switching part (e.g., a contact part) that switches between a conductive state and a non-conductive state. For example, if the electronic component 10M is a fuse, the component body 12 includes a fusing part that melts when an overcurrent flows. For example, if the electronic component 10M is a capacitor, the component body 12 includes a part that stores electric charge.

[0030] (Terminal) Terminal 13 is an electrical connection portion exposed to the outside of case 11. Terminal 13 is electrically connected to component main body 12 inside case 11. In this embodiment, electronic component 10M includes terminal 13A and terminal 13B as the multiple terminals 13. One of terminal 13A and terminal 13B is a positive terminal. The other of terminal 13A and terminal 13B is a negative terminal. One of terminal 13A and terminal 13B is an example of a "first terminal." The other of terminal 13A and terminal 13B is an example of a "second terminal."

[0031] In this embodiment, terminals 13A and 13B are provided at one end of electronic component 10M in the horizontal direction (e.g., the X direction). Terminals 13A and 13B are arranged side by side in the horizontal direction (e.g., the Y direction). Each terminal 13 has a mounting hole 13h to which a fastening member 71 (e.g., a screw or a bolt) described later is attached. Mounting hole 13h opens in the horizontal direction (e.g., the X direction). The inner circumferential surface of mounting hole 13h of electronic component 10M has a threaded groove.

[0032] (Mounting part) Mounting portion 14 is a portion for fixing electronic component 10M. Mounting portion 14 has mounting holes 14h to which fastening members 112 (e.g., screws or bolts, see FIG. 11) described later are attached. Mounting holes 14h are open in the Z direction. Mounting holes 14h are insertion holes through which fastening members 112 are passed. The destination to which mounting portion 14 is fixed will be described later.

[0033] <3.1.2 Type 1 connection parts> The first-type connecting part 20M is a part that electrically connects the first-type electronic component 10M and the wiring board 40. In this embodiment, the connecting part 20M electrically connects the electronic component 10M and a bus bar 42 (see FIG. 8) included in the wiring board 40. In this embodiment, the width L12 of the connecting part 20M in the longitudinal direction (e.g., X direction) of the electronic component 10M is smaller than the width L11 of the electronic component 10M in the longitudinal direction. The connecting part 20M has, for example, a first portion 21 and a second portion 22.

[0034] (Part 1) The first portion 21 of the connecting part 20M is a portion that is connected to the terminal 13 of the electronic component 10M. The first portion 21 is a plate-like or rectangular parallelepiped portion that extends in the Z direction. The first portion 21 extends in the Z direction along one end (e.g., an end in the X direction) of the electronic component 10M. The first portion 21 is an upright portion that stands in the Z direction relative to the wiring board 40 (e.g., relative to a bus bar 42 described below). The first portion 21 is adjacent to the electronic component 10M in the horizontal direction (e.g., the X direction). For example, the first portion 21 is adjacent to the terminal 13 of the electronic component 10M in the horizontal direction (e.g., the X direction) and is connected to the terminal 13 of the electronic component 10M from the horizontal direction (e.g., the X direction).

[0035] The first portion 21 of the connecting part 20M has a first mounting hole 21h through which a fastening member 71 (e.g., a screw or a bolt) is passed. The first mounting hole 21h is open in the horizontal direction (e.g., the X direction). The first portion 21 also has a recess 25 around the first mounting hole 21h. The recess 25 is a receiving portion that receives the head of the fastening member 71 inserted into the first mounting hole 21h. The fastening member 71 passed through the first mounting hole 21h engages with the mounting hole 13h of the terminal 13 of the electronic component 10M, thereby physically and electrically connecting the first portion 21 to the terminal 13 of the electronic component 10M. Note that the first portion 21 does not necessarily have to have the recess 25.

[0036] (Second part) The second portion 22 of the connection part 20M is a portion that is connected to the bus bar 42 (see FIG. 8). The second portion 22 protrudes horizontally (e.g., in the X direction) from the end of the first portion 21 on the −Z direction side. The second portion 22 is a plate portion that extends horizontally. The second portion 22 is adjacent to the bus bar 42 in the Z direction and is connected to the bus bar 42 from the Z direction. The second portion 22 of the connection part 20M is attached from the Z direction to a fastening member 43 (e.g., a screw or bolt, see FIG. 8) that protrudes from the bus bar 42 in the +Z direction, and is physically and electrically connected to the bus bar 42. In this embodiment, the second portion 22 of the connection part 20M has a second mounting hole 22h through which the fastening member 43 is passed. The second mounting hole 22h is open in the Z direction. The fastening member 43 is passed through the second mounting hole 22h of the second portion 22. Then, an engaging member 44 (e.g., a nut, see FIG. 3) engages with the tip of a fastening member 43 passed through the second mounting hole 22h, thereby fixing the second portion 22 to the bus bar 42. In this embodiment, the first portion 21 and the second portion 22 form an L-shaped, single-piece connecting part 20M.

[0037] <3.1.3 Second type electronic components> FIG. 6 is a perspective view showing a second-type electronic component 10N and a second-type connecting component 20N. The second-type electronic component 10N is an electronic component in which two terminals 13 are arranged separately at both horizontal ends of the electronic component 10N. The electronic component 10N includes, for example, a case 11, a component main body 12, and a plurality of terminals 13. Note that, among the components of the electronic component 10N, components having the same function as the electronic component 10M are denoted by the same reference numerals. In this case, in the description of the electronic component 10N, "electronic component 10M" can be read as "electronic component 10N" in the description of the electronic component 10M described above.

[0038] In electronic component 10N, terminals 13A and 13B are arranged separately at both ends of electronic component 10N in the horizontal direction (e.g., the X direction). Each terminal 13 has a mounting hole 13h to which a fastening member 72 (e.g., a screw or a bolt) described below is attached. Mounting hole 13h opens in the Z direction. For example, mounting hole 13h of electronic component 10N is an insertion hole through which fastening member 72 is passed. One of terminal 13A and terminal 13B is an example of a "first terminal." The other of terminal 13A and terminal 13B is an example of a "second terminal."

[0039] <3.1.4 Second type of connecting parts> The second-type connecting part 20N is a part that electrically connects the second-type electronic component 10N and the wiring board 40. In this embodiment, the connecting part 20N electrically connects the electronic component 10N and a bus bar 42 (see FIG. 8) included in the wiring board 40. In this embodiment, the width L12 of the connecting part 20N in the longitudinal direction (e.g., X direction) of the electronic component 10N is smaller than the width L11 of the electronic component 10N in the longitudinal direction. The connecting part 20N has, for example, a first portion 21, a second portion 22, and a third portion 23.

[0040] (Part 1) The first portion 21 of the connection part 20N is a portion connected to the terminal 13 of the electronic component 10N. The first portion 21 is a rectangular parallelepiped portion extending in the Z direction. The first portion 21 is an upright portion that stands in the Z direction relative to the routing board 40 (e.g., relative to the bus bar 42). The first portion 21 is adjacent to the terminal 13 of the electronic component 10N in the Z direction and is connected to the terminal 13 of the electronic component 10N from the Z direction. The first portion 21 of the connection part 20N has a first mounting hole 21h with which a fastening member 72 engages. The first mounting hole 21h opens in the Z direction. The inner circumferential surface of the first mounting hole 21h of the connection part 20N has a thread groove. The first portion 21 is physically and electrically connected to the terminal 13 of the electronic component 10N by engaging the fastening member 72 passed through the mounting hole 13h of the terminal 13 of the electronic component 10N with the mounting hole 21h of the first part 21.

[0041] (Second part) The second portion 22 of the connection part 20N is a portion that is connected to the bus bar 42 (see FIG. 8). The second portion 22 protrudes horizontally (e.g., in the X direction) from the end of the first portion 21 on the −Z direction side. The second portion 22 is a plate portion that extends horizontally. The second portion 22 is adjacent to the bus bar 42 in the Z direction and is connected to the bus bar 42 from the Z direction. The second portion 22 of the connection part 20N is attached from the Z direction to a fastening member 43 (e.g., a screw or bolt, see FIG. 8) that protrudes from the bus bar 42 in the +Z direction, and is physically and electrically connected to the bus bar 42. In this embodiment, the second portion 22 of the connection part 20N has a second mounting hole 22h through which the fastening member 43 is passed. The second mounting hole 22h is open in the Z direction. The fastening member 43, which will be described later, is passed through the second mounting hole 22h of the second portion 22. Then, second portion 22 is fixed to bus bar 42 by engaging an engaging member 44 (for example, a nut, see FIG. 3) with the tip of fastening member 43 passed through second mounting hole 22h.

[0042] (3rd part) The third portion 23 is an upright wall (side wall) that stands in the +Z direction from both horizontal end portions of the second portion 22. The third portion 23 is a wall that extends along the Z direction. The third portion 23 is connected to the first portion 21 and also to the second portion 22. The third portion 23 extends at an incline that increases in the X direction as it progresses in the -Z direction, for example. The third portion 23 may be provided in the connection part 20M described above. On the other hand, the connection part 20N may not have the third portion 23.

[0043] <3.2 External connection parts> Next, the connecting part 30 for external connection will be described. FIG. 7 is a perspective view showing a connection part 30 for external connection. The connection part 30 is a part that electrically connects an external connection bus bar 76 and a wiring board 40. In this embodiment, the connection part 30 electrically connects the external connection bus bar 76 and a bus bar 42 (see FIG. 8) included in the wiring board 40. The external connection bus bar 76 is electrically connected to an external device. In this disclosure, the term "external device" refers to an electrical device that exists outside the electrical connection unit 1. Examples of external devices include, but are not limited to, a battery unit mounted on a vehicle or an inverter for driving a vehicle motor. The connection part 30 has, for example, a first portion 31, a second portion 32, and a third portion 33.

[0044] (Part 1) The first portion 31 is a portion connected to the external connection busbar 76. The first portion 31 is a rectangular parallelepiped portion extending in the Z direction. The first portion 31 is an upright portion that stands in the Z direction relative to the wiring board 40 (e.g., relative to the busbar 42). The first portion 31 is adjacent to the external connection busbar 76 in the Z direction and is connected to the external connection busbar 76 from the Z direction. The first portion 31 has a first mounting hole 31h through which a fastening member 73 (e.g., a screw or a bolt) is passed. The first mounting hole 31h opens in the Z direction. The inner circumferential surface of the first mounting hole 31h has a thread groove. The first portion 31 is physically and electrically connected to the external connection busbar 76 by the fastening member 73 passed through the mounting hole 76h of the external connection busbar 76 engaging with the mounting hole 31h of the first portion 31.

[0045] (Second part) The second portion 32 is a portion that is connected to the bus bar 42 (see FIG. 8). The second portion 32 protrudes horizontally (e.g., in the X direction) from the end of the first portion 31 on the −Z direction side. The second portion 32 is a plate portion that extends horizontally. The second portion 32 is adjacent to the bus bar 42 in the Z direction and is connected to the bus bar 42 from the Z direction. The second portion 32 is attached from the Z direction to a fastening member 43 (e.g., a screw or bolt, see FIG. 8) that protrudes from the bus bar 42 in the +Z direction, and is physically and electrically connected to the bus bar 42. In this embodiment, the second portion 32 has a second mounting hole 32h through which the fastening member 43 is passed. The second mounting hole 32h is open in the Z direction. The fastening member 43, which will be described later, is passed through the second mounting hole 32h of the second portion 32. Then, second portion 32 is fixed to bus bar 42 by engaging an engaging member 44 (for example, a nut, see FIG. 3) with the tip of fastening member 43 passed through second mounting hole 32h.

[0046] (3rd part) The third portion 33 is an upright wall (side wall) that stands in the +Z direction from both horizontal end portions of the second portion 32. The third portion 33 is a wall that extends along the Z direction. The third portion 33 is connected to the first portion 31 and also to the second portion 32. The third portion 33 extends at an incline so that, for example, it becomes larger in the X direction (or Y direction) as it progresses in the -Z direction. Note that the connection part 30 does not necessarily have the third portion 33.

[0047] <3.3 Wiring board> Next, the wiring board 40 will be described. FIG. 8 is a perspective view of a wiring board 40. The wiring board 40 is a component that forms at least a portion of the electrical paths between multiple electronic components 10 and / or at least a portion of the electrical paths between the electronic components 10 and an external device. In this disclosure, the term "wiring board" refers to a board-type wiring structure. "Board-type" refers to a plate-like structure that is flat when viewed overall, regardless of its detailed shape. In this disclosure, "plate-like," "sheet-like," or "flat" does not necessarily mean a completely flat structure, but may also include a surface that partially contains a fixing structure or rib that protrudes in the Z direction, or a surface that has an uneven shape that conforms to the thickness of the bus bar. In this embodiment, the wiring board 40 is a plate-like structure that is flat in the X and Y directions.

[0048] The wiring board 40 includes, for example, a base plate 41, one or more (e.g., a plurality of) bus bars 42, and a plurality of fastening members 43. In this embodiment, the base plate 41 and the plurality of bus bars 42 are integrated by insert molding. For example, the wiring board 40 is formed as a single member by insert molding the bus bars 42 with the base plate 41 after the fastening members 43 are fixed to the bus bars 42. In other words, the bus bars 42 are integrated with the base plate 41 without using fastening members such as screws or bolts. Note that the wiring board 40 may be formed by another structure instead of insert molding. A modified example in which the wiring board 40 is formed by another structure will be described later.

[0049] 9 is a perspective view showing a partly exploded view of the wiring board 40. For convenience of explanation, the base plate 41, the bus bar 42, and the fastening member 43 will be described below with reference to the partly exploded view of the wiring board 40.

[0050] (base plate) The base plate 41 is a holding member that integrally holds together a plurality of bus bars 42 that are arranged horizontally at intervals from one another. The base plate 41 is made of, for example, synthetic resin and has insulating properties. The base plate 41 electrically insulates the plurality of bus bars 42 from one another. The base plate 41 is an example of a "base member." The base plate 41 may also be referred to as an "insulating substrate." The base plate 41 has, for example, a flat portion 51 and a plurality of fixing portions 52. The fixing portions 52 will be described later.

[0051] The flat surface portion 51 is a plate-shaped portion of the base plate 41. The flat surface portion 51 is a plate-shaped portion extending in the horizontal direction. The flat surface portion 51 forms the main portion of the base plate 41. The flat surface portion 51 forms the base portion (insulating base portion) of the base plate 41. In this embodiment, the flat surface portion 51 extends across the entire width of the base plate 41 in the X direction and across the entire width of the base plate 41 in the Y direction, excluding the four corner portions of the base plate 41.

[0052] The flat portion 51 has a first surface 51a and a second surface 51b. The first surface 51a is a surface facing the +Z direction. The first surface 51a is a flat surface extending along the horizontal direction. The first surface 51a faces the multiple electronic components 10 and also faces the insulating cover 93 (see FIG. 1) of the electrical connection unit 1. The second surface 51b is located on the opposite side to the first surface 51a. The second surface 51b is a surface facing the -Z direction. The second surface 51b is a flat surface extending along the horizontal direction. The second surface 51b faces the metal plate 80 (see FIG. 1). The thickness direction (plate thickness direction) of the flat portion 51 is the Z direction.

[0053] The flat portion 51 has, for example, one or more (e.g., multiple) accommodating portions 55 that each accommodate a bus bar 42. The multiple accommodating portions 55 are formed spaced apart from one another in the X direction or the Y direction. Each accommodating portion 55 is, for example, a through-hole that penetrates the flat portion 51 in the Z direction. Note that, instead of a through-hole, the accommodating portion 55 may be a recess that is provided on the first surface 51a or the second surface 51b of the flat portion 51 and recessed in the Z direction. Note that in the present disclosure, the phrase "an accommodating portion penetrates the flat portion in the first direction (Z direction)" may also include a case where only a portion of the entire length of the accommodating portion 55 penetrates the flat portion 51 in the Z direction (for example, the remaining portion of the accommodating portion 55 may be a recess that is recessed in the Z direction, or may be provided inside the base plate 41 and not exposed to the outside of the base plate 41). Similarly, in the present disclosure, "the storage section is recessed in the first direction (Z direction)" may also include the case where only a portion of the overall length of the storage section 55 is recessed in the Z direction (for example, the remaining portion of the storage section 55 may be a through hole that penetrates the planar section 51 in the Z direction, or may be provided inside the base plate 41 and not exposed to the outside of the base plate 41).

[0054] When viewed from the Z direction, each accommodating portion 55 has an outer shape corresponding to the shape of the bus bar 42 to be accommodated. In this embodiment, the planar portion 51 includes the plurality of accommodating portions 55, for example, five accommodating portions 55A, 55B, 55C, 55D, and 55E. The accommodating portion 55A is provided corresponding to a bus bar 42A (described later) and accommodates the bus bar 42A. The accommodating portion 55B is provided corresponding to a bus bar 42B (described later) and accommodates the bus bar 42B. The accommodating portion 55C is provided corresponding to a bus bar 42C (described later) and accommodates the bus bar 42C. The accommodating portion 55D is provided corresponding to a bus bar 42D (described later) and accommodates the bus bar 42D. The accommodating portion 55E is provided corresponding to a bus bar 42E (described later) and accommodates the bus bar 42E.

[0055] (busbar) The busbars 42 are routing members (electrical connection members) included in the routing board 40. The busbars 42 are, for example, routing members for electrically connecting multiple electronic components 10. Alternatively, the busbars 42 may be routing members for connecting the electronic components 10 to an external device. The busbars 42 are made of metal (for example, copper or a copper alloy) and are electrically conductive. In this embodiment, the routing board 40 has, as the multiple busbars 42, for example, five busbars 42A, 42B, 42C, 42D, and 42E. The five busbars 42A, 42B, 42C, 42D, and 42E are arranged horizontally at intervals from one another. The five busbars 42A, 42B, 42C, 42D, and 42E include portions that are arranged on the same plane. The five bus bars 42A, 42B, 42C, 42D, and 42E are held by a flat portion 51 of the base plate 41.

[0056] At least a portion of each busbar 42 has a plate shape extending in the horizontal direction. At least a portion of each busbar 42 is housed in the housing portion 55 and extends along the flat portion 51. That is, at least a portion of each busbar 42 extends along the first surface 51a of the flat portion 51. At least a portion of each busbar 42 extends horizontally within the housing portion 55. In this embodiment, each busbar 42 has a plate shape extending in the horizontal direction over the entire length of the busbar 42. Each busbar 42 is housed in the housing portion 55 over the entire length of the busbar 42 and extends along the flat portion 51. Hereinafter, the portion of each busbar 42 housed in the housing portion 55 and extending along the flat portion 51 may be referred to as a "plate portion 42p." The busbar 42 is a component that forms a horizontal current path. The busbar 42 may also be referred to as a "horizontal routing component."

[0057] 10 is a plan view showing the wiring board 40. The plate portion 42p of each bus bar 42 has, for example, a first connection portion 61, a second connection portion 62, and an extension portion 63.

[0058] The first connection portion 61 is a portion that comes into contact with one connection component 20 (hereinafter referred to as the "first connection component 20"). The first connection component 20 is a connection component that connects one electronic component 10 (hereinafter referred to as the "first electronic component 10") to the bus bar 42. The first connection portion 61 is a portion of the bus bar 42 that overlaps with the first connection component 20 when viewed from the Z direction. The first connection portion 61 is adjacent to the first connection component 20 in the Z direction and is connected to the first connection component 20 from the Z direction.

[0059] The second connection portion 62 is a portion that comes into contact with another connection component 20 (hereinafter referred to as the "second connection component 20"). The second connection component 20 is a connection component that connects another electronic component 10 (hereinafter referred to as the "second electronic component 10") included in the plurality of electronic components 10 to the bus bar 42. The second connection portion 62 is a portion of the bus bar 42 that overlaps with the second connection component 20 when viewed from the Z direction. The second connection portion 62 is adjacent to the second connection component 20 in the Z direction and is connected to the second connection component 20 from the Z direction.

[0060] Alternatively, the second connection portion 62 may be a portion that comes into contact with another connection component 30 (hereinafter referred to as the "second connection component 30") instead of the above example. The connection component 30 is a connection component for connecting an external device to the bus bar 42. In this case, the second connection portion 62 is a portion of the bus bar 42 that overlaps with the second connection component 30 when viewed from the Z direction. The second connection portion 62 is adjacent to the second connection component 30 in the Z direction and is connected to the second connection component 30 from the Z direction.

[0061] Furthermore, the second connection portion 62 may be a portion that comes into contact with the coupling bus bar 75 for connecting to another subunit SU, instead of the connection parts 20 and 30. In this case, the second connection portion 62 is a portion of the bus bar 42 that overlaps with the coupling bus bar 75 when viewed from the Z direction. The second connection portion 62 is adjacent to the coupling bus bar 75 in the Z direction, and is connected to the coupling bus bar 75 from the Z direction.

[0062] The extending portion 63 extends in the X direction or the Y direction from the first connecting portion 61. The extending portion 63 is provided between the first connecting portion 61 and the second connecting portion 62. The extending portion 63 extends across the first connecting portion 61 and the second connecting portion 62. The extending portion 63 connects the first connecting portion 61 and the second connecting portion 62.

[0063] In this embodiment, the first connection portion 61, the second connection portion 62, and the extension portion 63 are plate-shaped and extend in the horizontal direction. In this embodiment, each bus bar 42 is housed in the housing portion 55 across at least the first connection portion 61 and the second connection portion 62, and extends along the flat portion 51. For example, the first connection portion 61, the second connection portion 62, and the extension portion 63 are housed in the housing portion 55 and extend along the flat portion 51.

[0064] In this embodiment, the extension portions 63 of some of the bus bars 42 are accommodated in the accommodation portion 55, and thereby pass through the region R that overlaps with the electronic component 10 when viewed from the Z direction, and extend to both sides of the region R. For example, the extension portions 63 extend linearly along the X direction. The extension portions 63 extend through the region R that overlaps with the electronic component 10 when viewed from the Z direction, and extend to both the +X direction side and the −X direction side of the region R. In other words, by accommodating the bus bars 42 in the accommodation portion 55, they can be more easily routed along a better route (for example, a route with a shorter distance) without being obstructed by the presence of the electronic component 10.

[0065] Furthermore, one or more bus bars 42 may have an extension portion 64 in addition to the first connection portion 61, the second connection portion 62, and the extension portion 63. The extension portion 64 is a portion of the bus bar 42 extended for the purpose of increasing the heat dissipation area and / or the heat capacity for heat storage (heat absorption). The extension portion 64 is a portion not used for electrical connection. For example, the extension portion 64 is located on the opposite side of the extension portion 63 from the first connection portion 61 (or the second connection portion 62). The extension portion 64 has a plate shape extending horizontally. The extension portion 64 is housed in the housing portion 55 and extends along the flat portion 51. The extension portion 64 extends to a region R that overlaps with the electronic component 10 when viewed from the Z direction, and has an end 42e1 of the bus bar 42 at a position that overlaps with the electronic component 10 when viewed from the Z direction.

[0066] Below, several examples of busbar 42 routing will be described. The plurality of electronic components 10 includes three electronic components 10A, 10B, and 10C. Electronic component 10A and electronic component 10B are, for example, a first-type electronic component 10M. Electronic component 10C is, for example, a second-type electronic component 10N. The types of electronic components 10 are not limited to the above examples. The plurality of connection components 20 include six connection components 20A, 20B, 20C, 20D, 20E, and 20F. The plurality of connection components 30 include two connection components 30A and 30B. The plurality of coupling bus bars 75 include two coupling bus bars 75A and 75B. The plurality of external connection bus bars 76 include two external connection bus bars 76A and 76B.

[0067] (1st wiring example) First, an example of wiring of bus bar 42A will be described. Bus bar 42A has a first connection portion 61, a second connection portion 62, and an extension portion 63. When viewed from the Z direction, first connection portion 61 is located on the +X direction side of electronic component 10A. First connection portion 61 is electrically connected to terminal 13A of electronic component 10A via connection component 20A, which is first connection component 20. Second connection portion 62 is located on the −X direction side of electronic component 10A when viewed from the Z direction. Second connection portion 62 is electrically connected to another subunit SU via coupling bus bar 75A.

[0068] By being accommodated in accommodation portion 55, extension portion 63 passes through region R that overlaps with electronic component 10A when viewed from the Z direction, and extends to both sides of region R. For example, extension portion 63 extends linearly along the X direction. Extension portion 63 extends through region R that overlaps with electronic component 10A when viewed from the Z direction, to both the +X direction side and the −X direction side of region R. Bus bar 42A is an example of a “first bus bar.” Accommodation portion 55A that accommodates bus bar 42A is an example of a “first accommodation portion.” Bus bar 42A is, for example, a bus bar included in a positive electrode line PL of electrical connection unit 1.

[0069] (Second wiring example) Next, an example of wiring of the busbar 42B will be described. The busbar 42B has a first connection portion 61, a second connection portion 62, an extension portion 63, and an extension portion 64. The first connection portion 61 is electrically connected to a terminal 13B of the electronic component 10A via a connection component 20B, which is the first connection component 20. The second connection portion 62 is electrically connected to an external connection busbar 76A via a connection component 30A, which is the second connection component 30. The extension portion 64 extends to a region R that overlaps with the electronic component 10A when viewed from the Z direction, and has an end 42e1 of the busbar 42 at a position that overlaps with the electronic component 10A. Note that, like the busbar 42A, the busbar 42B may have an extension portion 63 that passes through the region R that overlaps with the electronic component 10A when viewed from the Z direction and extends to both sides of the region R. The busbar 42B is another example of a "first busbar." Accommodating portion 55B that accommodates bus bar 42B is another example of a “first accommodating portion.” Bus bar 42B is a bus bar included in positive electrode line PL of electrical connection unit 1, for example.

[0070] (3rd wiring example) Next, an example of wiring of the busbar 42C will be described. The busbar 42C has a first connection portion 61, a second connection portion 62, an extension portion 63, and an extension portion 64. The first connection portion 61 is electrically connected to a terminal 13B of the electronic component 10B via a connection component 20C, which is the first connection component 20. The second connection portion 62 is electrically connected to another subunit SU via a coupling busbar 75B. The extension portion 64 extends to a region R that overlaps with the electronic component 10B when viewed from the Z direction, and has an end 42e1 of the busbar 42 at a position that overlaps with the electronic component 10B when viewed from the Z direction. The busbar 42C is another example of a "first busbar." The accommodation portion 55C that accommodates the busbar 42C is another example of a "first accommodation portion." The busbar 42C is, for example, a busbar included in the negative electrode line NL of the electrical connection unit 1.

[0071] (4th wiring example) Next, an example of wiring of the busbar 42D will be described. The busbar 42D has a first connection portion 61, a second connection portion 62, and an extension portion 63. The first connection portion 61 is electrically connected to a terminal 13A of the electronic component 10B via a connection part 20D, which is a first connection part 20. The second connection portion 62 is electrically connected to a terminal 13B of the electronic component 10C via a connection part 20E, which is a second connection part 20. The busbar 42D is another example of a "first busbar." The accommodation portion 55D that accommodates the busbar 42D is another example of a "first accommodation portion." The busbar 42D is, for example, a busbar included in the negative electrode line NL of the electrical connection unit 1.

[0072] (5th wiring example) Next, an example of wiring of the bus bar 42E will be described. The bus bar 42E has a first connection portion 61, a second connection portion 62, and an extension portion 63. The first connection portion 61 is electrically connected to a terminal 13A of the electronic component 10C via a connection part 20F, which is a first connection part 20. The second connection portion 62 is electrically connected to an external connection bus bar 76B via a connection part 30B, which is a second connection part 30. The bus bar 42E is another example of a "first bus bar." The accommodation portion 55E that accommodates the bus bar 42E is another example of a "first accommodation portion." The bus bar 42E is, for example, a bus bar included in the negative electrode line NL of the electrical connection unit 1.

[0073] (Fastening member) Next, returning to Fig. 9, fastening member 43 will be described. Fastening member 43 is a component for fastening bus bar 42 to a component to be connected to bus bar 42 (connection component 20, connection component 30, coupling bus bar 75, or connection component 100). Fastening member 43 is, for example, a crimp bolt fixed to bus bar 42. Fastening member 43 is an example of a "fastening portion."

[0074] In this embodiment, each of the first connection portion 61 and the second connection portion 62 of the bus bar 42 has a through hole 42h. The through hole 42h penetrates the bus bar 42 in the Z direction. The fastening member 43 is, for example, a bolt having a shaft portion 43a and a head portion 43b. The circumferential surface of the shaft portion 43a has a thread groove. The head portion 43b has a larger diameter than the shaft portion 43a. The fastening member 43 is fixed to the bus bar 42 by crimping, with the shaft portion 43a passing through the through hole 42h of the bus bar 42. With this fixation, the fastening member 43 is electrically and physically connected to the bus bar 42, with the shaft portion 43a protruding from the through hole 42h of the bus bar 42 in the +Z direction. Note that the fastening member 43 is not limited to being fixed by crimping, and may be fixed to the bus bar 42 by welding or other methods.

[0075] In this embodiment, the connecting part 20 is first fixed to the electronic component 10 by the fastening member 71 or the fastening member 72, and then attached to the fastening member 43 from the Z direction. For example, the connecting part 20 has the shaft portion 43a of the fastening member 43 inserted into the second mounting hole 22h of the second part 22. Then, an engaging member 44 (e.g., a nut) is engaged with the shaft portion 43a of the fastening member 43 protruding from the second mounting hole 22h of the second part 22 of the connecting part 20. The engaging member 44 is attached to the shaft portion 43a, for example, along the Z direction. This engagement fixes the second part 22 of the connecting part 20 to the fastening member 43.

[0076] <4. Metal plates, insulating sheets, heat transfer members, and insulating covers> Next, the metal plate 80, the insulating sheet 91, the heat transfer member 92, and the insulating cover 93 will be described.

[0077] <4.1 Metal Plate> 11 is a partially exploded perspective view of the electrical connection unit 1. The metal plate 80 is a member that ensures the rigidity of the electrical connection unit 1 and also enhances the heat dissipation properties of the electrical connection unit 1. The metal plate 80 is made of metal (for example, aluminum or an aluminum alloy). The metal plate 80 may also be referred to as a "rigid member."

[0078] When viewed from the Z direction, the metal plate 80 has a rectangular shape extending along the X direction. The metal plate 80 has a first end 80e1, a second end 80e2, a third end 80e3, and a fourth end 80e4. The first end 80e1 and the second end 80e2 are a pair of ends in the longitudinal direction of the metal plate 80 and are spaced apart in the X direction. The third end 80e3 and the fourth end 80e4 are a pair of ends in the lateral direction of the metal plate 80 and are spaced apart in the Y direction. The metal plate 80 includes, for example, a flat portion 81, a plurality of fixing portions 82, and a plurality of fixing portions 83.

[0079] The flat surface portion 81 is a portion of the metal plate 80 that is formed into a plate shape. The flat surface portion 81 is a plate-like portion that extends horizontally. The flat surface portion 81 forms the main portion of the metal plate 80. The flat surface portion 81 forms the base (metal base) of the metal plate 80. In this embodiment, the flat surface portion 81 is large enough to cover the three subunits SU from below. The flat surface portion 81 faces the wiring board 40 of the three subunits SU. In this embodiment, the metal plate 80 has a gap S1 (see FIG. 13) between itself and the second surface 51b of the flat surface portion 51 of each subunit SU, and faces the second surface 51b of the flat surface portion 51 of each subunit SU. The gap S1 is an example of a "first gap."

[0080] The fixing portion 82 is a fixing portion for fixing the base plate 41 of each subunit SU to the metal plate 80. When viewed from the Z direction, the fixing portion 82 is provided at a position corresponding to the fixing portion 52 of the base plate 41 of each subunit SU. The fixing portion 82 is a cylindrical or prismatic boss that protrudes from the flat portion 81 of the metal plate 80 in the +Z direction.

[0081] The fixing portion 83 is a fixing portion for fixing the electronic component 10 of each subunit SU directly to the metal plate 80 without using the base plate 41. When viewed from the Z direction, the fixing portion 83 is provided at a position corresponding to the mounting portion 14 of the electronic component 10 of each subunit SU. The fixing portion 83 is a cylindrical or prismatic boss that protrudes from the flat portion 81 in the +Z direction.

[0082] <4.2 Insulation sheet> The insulating sheet 91 is an insulating member for electrically insulating the metal plate 80 from the bus bars 42 of each subunit SU. The insulating sheet 91 is made of a synthetic resin such as polyester or polyimide, and has insulating properties. The insulating sheet 91 has a rectangular shape when viewed from the Z direction. The insulating sheet 91 has a sheet shape that extends horizontally. The insulating sheet 91 is disposed between the flat surface 81 of the metal plate 80 and the wiring board 40 of each subunit SU. For example, the insulating sheet 91 is disposed between the flat surface 81 of the metal plate 80 and a plurality of heat transfer members 92.

[0083] In this embodiment, the insulating sheet 91 is attached to the flat portion 81 of the metal plate 80. The insulating sheet 91 has cutouts or openings to avoid the fixing portions 82 and 83 of the metal plate 80. Note that, instead of the above example, the insulating sheet 91 may be provided between the wiring board 40 of each subunit SU and the plurality of heat transfer members 92. Note that if the heat transfer members 92 have insulating properties and the necessary insulation is ensured by the heat transfer members 92, the insulating sheet 91 may be omitted.

[0084] 4.3 Heat transfer materials The heat transfer member 92 is a member for transferring heat generated by the electronic component 10 when current is applied and / or heat (Joule heat) generated by the bus bar 42 itself when current is applied to the metal plate 80. The heat transfer member 92 is, for example, an elastic heat transfer sheet (for example, a thermally conductive silicone sheet). The heat transfer member 92 is formed of, for example, a material with higher thermal conductivity than the base plate 41. However, the heat transfer member 92 is not limited to the above example, and may be a heat transfer member formed of a thermally conductive gel or other material.

[0085] 12 is a bottom view showing the wiring board 40. In this embodiment, the plurality of heat transfer members 92 are provided partially on the wiring board 40. For example, the plurality of heat transfer members 92 are arranged at positions overlapping with portions of the bus bars 42 when viewed from the Z direction. Furthermore, the plurality of heat transfer members 92 are arranged at positions overlapping with portions of the bus bars 42 near the electronic components 10 (e.g., electronic components 10A and 10B) when viewed from the Z direction. In this embodiment, the plurality of heat transfer members 92 are arranged at positions overlapping with the connecting components 20 when viewed from the Z direction.

[0086] Fig. 13 is a cross-sectional view taken along line F13-F13 of the structure shown in Fig. 10. In this embodiment, heat transfer member 92 is disposed between metal plate 80 and bus bar 42. Heat transfer member 92 transfers heat transferred from electronic component 10 to bus bar 42 and / or heat generated in bus bar 42 from bus bar 42 to metal plate 80.

[0087] In this embodiment, a portion of the heat transfer member 92 contacts the bus bar 42 at a position that overlaps the connection component 20 when viewed from the Z direction. In this case, the heat transfer member 92 makes it easier to transfer heat that is transferred from the terminal 13 of the electronic component 10 to the connection component 20 from the connection component 20 to the metal plate 80 via the bus bar 42.

[0088] In this embodiment, a portion of the heat transfer member 92 is disposed at a position overlapping with the head 43b of the fastening member 43 when viewed from the Z direction, and is in contact with the head 43b of the fastening member 43. In this case, the heat transfer member 92 facilitates the transfer of heat, which is transferred from the terminal 13 of the electronic component 10 to the connecting part 20, from the fastening member 43 to the metal plate 80.

[0089] In this embodiment, a portion of the heat transfer member 92 contacts the bus bar 42 at a position that overlaps the electronic component 10 when viewed from the Z direction. In this case, the heat transfer member 92 makes it easier to transfer heat, which is transferred from the electronic component 10 to the bus bar 42, from the bus bar 42 to the metal plate 80. In the example shown in FIG. 13 , the upper surface of the bus bar 42 contacts the electronic component 10, so that the bus bar 42 is thermally connected to the electronic component 10. Note that the portion of the bus bar 42 that is thermally connected to the electronic component 10 may be the extension portion 63 or the extension portion 64.

[0090] <4.4 Insulation cover> Returning to FIG. 1, the insulating cover 93 will be described. The insulating cover 93 is a member for preventing contact with the current-carrying paths of the main body unit MU. The insulating cover 93 is made of, for example, synthetic resin and has insulating properties. The insulating cover 93 is, for example, box-shaped with an open side in the -Z direction. The insulating cover 93 has a plurality of ventilation holes 93h. The insulating cover 93 is attached to the metal plate 80 along the Z direction. Note that the insulating cover 93 is not limited to a box-shaped member, and may be a sheet-shaped member that covers the current-carrying paths of the main body unit MU.

[0091] <5. Exposed busbar structure> Next, the exposed structure of the bus bar 42 will be described.

[0092] <5.1 Exposed structure on the top side of the busbar> First, the exposed structure of the upper surface side of the busbar 42 will be described with reference to Fig. 8. In this embodiment, at least a portion of the extension portion 63 of the busbar 42 is exposed to the outside of the base plate 41 on the upper surface side (the side of the first surface 51a of the flat portion 51). For example, the extension portion 63 of the busbar 42 is exposed to the outside of the base plate 41 on the upper surface side at least in a part of the region R (see Fig. 10) that overlaps with the electronic component 10 when viewed from the Z direction.

[0093] In this embodiment, the bus bar 42 is accommodated in the accommodation portion 55 over at least the entire length between the first connection portion 61 and the second connection portion 62 and extends along the first surface 51a of the flat portion 51. The bus bar 42 is exposed to the outside of the base plate 41 on the upper surface side over at least the entire length between the first connection portion 61 and the second connection portion 62.

[0094] In this embodiment, bus bar 42 is accommodated in accommodation portion 55 over the entire length of bus bar 42 and extends along first surface 51a of flat portion 51. Bus bar 42 is exposed to the outside of base plate 41 on the upper surface side over the entire length of bus bar 42.

[0095] 13, at least a portion of the extending portion 63 of the bus bar 42 is exposed to the outside of the base plate 41 not only on the upper surface side but also on the lower surface side (the side facing the second surface 51b). For example, the lower surface side of the bus bar 42 is exposed to the outside of the base plate 41 over the entire length of the bus bar 42.

[0096] <5.2 Exposed structure of the underside of the busbar> The exposed structure of the lower surface side of the busbar 42 will be described with reference to Fig. 13. In this embodiment, the plate portion 42p of the busbar 42 includes an exposed portion 42u on the lower surface side (the second surface 51b side of the flat portion 51) that is exposed to the outside of the base plate 41. In this embodiment, the exposed portion 42u of the busbar 42 extends over the entire length of the busbar 42. In this embodiment, the heat transfer member 92 is disposed between the exposed portion 42u of the busbar 42 and the metal plate 80. For example, the heat transfer member 92 contacts the exposed portion 42u of the busbar 42.

[0097] In this embodiment, at least a portion of the exposed portion 42u of the bus bar 42 is provided in a region that overlaps with the connection part 20 when viewed from the Z direction. At least a portion of the heat transfer member 92 overlaps with the exposed portion 42u of the bus bar 42 in a region that overlaps with the connection part 20 when viewed from the Z direction. For example, at least a portion of the heat transfer member 92 is in contact with the exposed portion 42u of the bus bar 42 in a region that overlaps with the connection part 20 when viewed from the Z direction.

[0098] 14, the contact surface COS between the heat transfer member 92 and the exposed portion 42u (42ua) is closer to the metal plate 80 in the first direction (Z direction) than the second surface 51b. In other words, the second surface 51b is recessed in the Z direction with respect to the contact surface COS. At this time, a portion of the side peripheral surface 42CS of the bus bar 42 is exposed to the outside of the base plate 41. The side peripheral surface 42CS faces in a direction intersecting the first direction.

[0099] Furthermore, the thickness of the busbar 42 in the first direction (Z direction) may be greater than the thickness of the second surface 51b of the base plate 41 in the Z direction. This allows the cross-sectional area of ​​the busbar 42 to be larger than when the thickness of the busbar 42 and the thickness of the second surface 51b of the base plate 41 are the same value. A larger rated current can be adopted for the electrical connection unit 1 including the busbar 42. The rated current can be determined by substituting the cross-sectional area into the upper limit of the current density for the rated current (JIS C8480:2016, "Current Density of Strip Conductors"). In this case, as described above, a portion of the side peripheral surface 42CS is exposed to the outside of the base plate 41, thereby improving the heat dissipation performance of the busbar 42.

[0100] The position of the heat transfer member 92 is not limited to the position disclosed above. For example, at least a portion of the heat transfer member 92 may overlap the exposed portion 42u of the bus bar 42 in a region that overlaps with the connection part 30 when viewed from the Z direction. In this case, the heat transfer member 92 receives heat from an external device via the external connection bus bar 76, and transfers and dissipates the received heat using the metal plate 80.

[0101] Additionally, at least a portion of the heat transfer member 92 may overlap with the connecting bus bar 75 in a region that overlaps with the second connection portion 62 when viewed from the Z direction. In this case, the heat transfer member 92 receives heat from another subunit via the connecting bus bar 75, and transfers the received heat by the metal plate 80 to dissipate it.

[0102] In this embodiment, the exposed portion 42u of the busbar 42 includes a first portion 42ua arranged in an area that overlaps with the connecting component 20 when viewed from the Z direction, and a second portion 42ub arranged in an area that overlaps with the electronic component 10 when viewed from the Z direction.

[0103] The heat transfer member 92 includes a first heat transfer portion 92a and a second heat transfer portion 92b. The first heat transfer portion 92a overlaps with the first portion 42ua of the exposed portion 42u of the busbar 42 in a region that overlaps with the connection part 20 when viewed from the Z direction. For example, the first heat transfer portion 92a contacts the first portion 42ua of the exposed portion 42u of the busbar 42. On the other hand, the second heat transfer portion 92b overlaps with the second portion 42ub of the exposed portion 42u of the busbar 42 in a region that overlaps with the electronic component 10 when viewed from the Z direction. For example, the second heat transfer portion 92b contacts the second portion 42ub of the exposed portion 42u of the busbar 42.

[0104] As described above, at least a portion of the extending portion 63 of the bus bar 42 is exposed to the outside of the base plate 41 not only on the lower surface side but also on the upper surface side (first surface 51a side). For example, the bus bar 42 is exposed to the outside of the base plate 41 on the upper surface side over the entire length of the bus bar 42. For example, the second portion 42ub of the exposed portion 42u of the bus bar 42 is exposed to the outside of the base plate 41 not only on the lower surface side but also on the upper surface side, and faces the electronic component 10.

[0105] <6. Three-dimensional busbar wiring structure> Next, the three-dimensional wiring structure CS of the bus bar 42 will be described. Fig. 15 is a perspective view showing the three-dimensional wiring structure CS of the busbar 42. Fig. 16 is a plan view showing the three-dimensional wiring structure CS of the busbar 42. The three-dimensional wiring structure CS has busbar 42F, busbar 42G, busbar 42H, and busbar 42I as the multiple busbars 42. The three-dimensional wiring structure CS also includes multiple connection parts 100. The three-dimensional intersection structure CS also includes coupling busbar 75C and coupling busbar 75D as the multiple coupling busbars 75.

[0106] The busbars 42F and 42G are, for example, busbars 42 included in the subunit SUY. The flat portion 51 of the base plate 41 of the subunit SUY has a plurality of housing portions 55, namely, housing portion 55F and housing portion 55G. The busbar 42F is housed in housing portion 55F and extends along the flat portion 51. The busbar 42G is housed in housing portion 55G and extends along the flat portion 51. The busbar 42F is an example of a "first busbar." The housing portion 55F that houses the busbar 42F is an example of a "first housing portion." The busbars 42F and 42G are busbars 42 located in the first layer (lower layer) of the three-dimensional wiring structure CS.

[0107] In this embodiment, bus bar 42F has a first portion 42Fa extending in the X direction and a second portion 42Fb bending from first portion 42Fa and extending in the Y direction. Second portion 42Fb extends along boundary B between subunit SUY and subunit SUZ.

[0108] On the other hand, busbar 42H and busbar 42I are, for example, busbars 42 included in subunit SUZ. Planar portion 51 of base plate 41 of subunit SUZ has housing portion 55H and housing portion 55I as the multiple housing portions 55. Busbar 42H is housed in housing portion 55H and extends along planar portion 51. Busbar 42I is housed in housing portion 55I and extends along planar portion 51. Busbar 42H and busbar 42I are busbars 42 located in the first layer (lower layer) of three-dimensional wiring structure CS.

[0109] The connecting component 100 has a configuration similar to the connecting component 30 for external connection described above. For example, the connecting component 100 has a first portion 101, a second portion 102, and a third portion 103. Details of the connecting component 100 can be obtained by replacing "connecting component 30" with "connecting component 100," "first portion 31" with "first portion 101," "first mounting hole 31h" with "first mounting hole 101h," "second portion 32" with "second portion 102," "second mounting hole 32h" with "second mounting hole 102h," and "third portion 33" with "third portion 103" in the description of the connecting component 30 described above. The connecting component 100 is a component that forms a vertical electrical path. The connecting component 100 may also be referred to as a "vertical routing component."

[0110] The multiple connection parts 100 include connection part 100A and connection part 100B. When viewed from the Z direction, connection part 100A overlaps with the second connection part 62 of bus bar 42G in subunit SUY. Connection part 100A is adjacent to the second connection part 62 of bus bar 42G in the Z direction and is connected to the second connection part 62 of bus bar 42G from the Z direction. Connection part 100A stands upright from bus bar 42G in the +Z direction. Connection part 100A is an example of a "third connection part."

[0111] When viewed from the Z direction, connection part 100B overlaps with second connection part 62 of bus bar 42I in subunit SUZ. Connection part 100B is adjacent to second connection part 62 of bus bar 42I in the Z direction, and is connected to second connection part 62 of bus bar 42I from the Z direction. Connection part 100B stands upright in the +Z direction from bus bar 42I.

[0112] One end of the connecting busbar 75C is adjacent to the second connection portion 62 of the busbar 42F in the Z direction in the subunit SUY and is connected to the second connection portion 62 of the busbar 42F from the Z direction. The other end of the connecting busbar 75C is adjacent to the second connection portion 62 of the busbar 42H in the subunit SUZ in the Z direction and is connected to the second connection portion 62 of the busbar 42H from the Z direction. With this configuration, the busbar 42F of the subunit SUY and the busbar 42H of the subunit SUZ are electrically connected via the connecting busbar 75C. The connecting busbar 75C is the busbar 75 located in the first layer (lower layer) of the three-dimensional wiring structure CS.

[0113] On the other hand, in subunit SUY, coupling bus bar 75D is adjacent to first portion 101 of connection part 100A in the Z direction and is connected to first portion 101 of connection part 100A from the Z direction. The other end of coupling bus bar 75D is adjacent to first portion 101 of connection part 100B in the Z direction and is connected to first portion 101 of connection part 100B from the Z direction in subunit SUZ.

[0114] The coupling bus bar 75D is supported by the first portion 101 of the connection part 100A and the first portion 101 of the connection part 100B at a position spaced apart from the bus bar 42F in the Z direction. The coupling bus bar 75D is supported by the first portion 101 of the connection part 100A and the first portion 101 of the connection part 100B and extends horizontally (e.g., in the X direction). The coupling bus bar 75D is electrically connected to the first portion 101 of the connection part 100A and the first portion 101 of the connection part 100B. With this configuration, the bus bar 42F of the subunit SUY and the bus bar 42I of the subunit SUZ are electrically connected via the two connection parts 100 and the coupling bus bar 75D.

[0115] In the present embodiment, coupling bus bar 75D extends so as to straddle second portion 42Fb of bus bar 42F at a position spaced apart from bus bar 42F in the +Z direction. This forms a three-dimensional wiring structure between coupling bus bar 75D and bus bar 42F. In the present embodiment, coupling bus bar 75D extends so as to straddle boundaries B between multiple subunits SU.

[0116] In this embodiment, the three-dimensional routing structure CS of the busbar 42 is provided at a position that straddles the boundary B between the plurality of subunits SU. With this arrangement, the three-dimensional routing structure CS reinforces the connection structure between the plurality of subunits SU. Note that instead of being provided at the boundary B between the plurality of subunits SU, the three-dimensional routing structure CS of the busbar 42 may be provided inside one or more of the subunits SU.

[0117] <7. Advantages> As a comparative example, consider an electrical connection unit in which bus bars are arranged in an upright position relative to the bottom wall of the housing. In such a comparative example, it may be difficult to reduce the width (height) of the upright bus bars because the cross-sectional area of ​​the bus bars is determined to function as wiring materials, for example. In this case, the width of the upright bus bars becomes a bottleneck, making it difficult to reduce the height of the electrical connection unit.

[0118] On the other hand, in this embodiment, the electrical connection unit 1 includes a first electronic component 10 and a wiring board 40. The wiring board 40 includes a base member 41 and a first bus bar 42. The base member 41 has a plate-like or sheet-like flat portion 51 with a first surface 51a facing the first electronic component 10. The flat portion 51 has a first housing portion 55 that is recessed in the Z direction or that penetrates the flat portion 51 in the Z direction. At least a portion of the first bus bar 42 is housed in the first housing portion 55 and extends along the flat portion 51. With this configuration, compared to the structure of the comparative example in which at least a portion of the wiring path is formed on a flat surface, the width of the bus bar is less likely to become a bottleneck, making it easier to reduce the height of the electrical connection unit 1.

[0119] This embodiment also focuses on the arrangement of the heat transfer member 92. For example, as shown in Fig. 17, when a portion of the heat transfer member 92' is in contact with both the bus bar 42 and the base plate 41', if the second surface 51b of the base plate 41 protrudes in the first direction (Z direction) relative to the contact surface COS, the second surface 51b presses down on the heat transfer member 92 in the -Z direction. This makes it difficult to ensure the contact area of ​​the contact surface COS, and the heat dissipation performance of the heat transfer member 92 placed in that location is difficult to ensure.

[0120] In this embodiment, the contact surface COS between the heat transfer member 92 and the exposed portion 42u (42ua) is closer to the metal plate 80 in the first direction (Z direction) than the second surface 51b. With this configuration, the second surface 51b of the base plate 41 is less likely to protrude in the Z direction relative to the contact surface COS, and the second surface 51b is less likely to press down on the heat transfer member 92 in the -Z direction. Since the contact area of ​​the contact surface COS is more likely to be secured, the heat dissipation performance of the heat transfer member 92 installed in that location is more likely to be ensured.

[0121] In this embodiment, the thickness of the busbar 42 in the first direction (Z direction) is greater than the thickness of the flat portion 51 of the base member (e.g., base plate 41) in the first direction. With this configuration, the cross-sectional area of ​​the busbar 42 can be made larger than when the thickness of the busbar 42 and the thickness of the second surface 51b of the base plate 41 are the same value. A larger rated current can be adopted for the electrical connection unit 1 including the busbar 42. The rated current can be calculated by substituting the cross-sectional area into the specification for the upper limit of the current density for the rated current (JIS C8480:2016, "Current Density of Strip Conductors").

[0122] In the present embodiment, the bus bar 42 is housed in the housing portion 55 over the entire length of the bus bar 42 and extends along the flat portion 51. This configuration improves the assembly of the electrical connection unit 1 and also makes it easier to reduce the height of the electrical connection unit 1.

[0123] In this embodiment, bus bar 42 is accommodated in accommodation portion 55 over the entire length thereof, extends along flat portion 51, and is exposed to the outside of base plate 41 on the second surface 51b side. With this configuration, a wider portion functions as a heat dissipation area, thereby further improving the heat dissipation performance of electrical connection unit 1.

[0124] In this embodiment, a portion of the side peripheral surface 42CS of the bus bar 42, which faces in a direction intersecting the first direction (Z direction), is exposed to the outside of the base member (for example, the base plate 41). With this configuration, the portion of the side peripheral surface 42CS functions as a heat dissipation area, thereby further improving the heat dissipation performance of the electrical connection unit 1.

[0125] In this embodiment, the bus bar 42 is integrated with the base member (for example, the base plate 41). This configuration can eliminate or reduce the work of manually attaching the bus bar 42 to the housing. Since the bus bar 42 is less likely to fall out of the accommodating portion 55, the assembly of the electrical connection unit 1 can be further improved. For example, the bus bar 42 is integrated with the base member (for example, the base plate 41) by insert molding.

[0126] In a modified example described below, the bus bar 42 is covered with an insulating sheet. With this configuration, it is easier to reduce the voltage drop and inductance compared to a non-laminated bus bar.

[0127] (Second embodiment) Next, a second embodiment will be described. The second embodiment differs from the first embodiment in that an insulating rib 53 is provided between two adjacent bus bars 42. Note that the configuration other than that described below is the same as the configuration of the first embodiment.

[0128] FIG. 18 is a perspective view illustrating the insulating rib 53. In this embodiment, the base plate 41 has the insulating rib 53. The insulating rib 53 is a rib that stands up in the −Z direction from the second surface 51b of the flat portion 51. The insulating rib 53 is made of synthetic resin and has insulating properties. The insulating rib 53 is an example of an “insulating wall.” The insulating rib 53 is provided, for example, as part of the base plate 41. The insulating rib 53 is arranged between two bus bars 42 that are arranged side by side with their lower surfaces exposed, and ensures an insulating distance between the two bus bars 42.

[0129] When viewed from the Z direction, insulating rib 53 is located between bus bar 42A and bus bar 42B and extends in the X direction parallel to bus bar 42A and bus bar 42B. Bus bar 42A, bus bar 42B, and insulating rib 53 may extend linearly in the Y direction instead of the X direction.

[0130] Fig. 19 shows a cross-sectional view taken along line F19-F19 of the structure shown in Fig. 18. As shown in Fig. 19, insulating rib 53 is located between side peripheral surface 42CS of bus bar 42A and side peripheral surface 42CS of bus bar 42B in the Y direction. Insulating rib 53 electrically insulates side peripheral surface 42CS of bus bar 42A from side peripheral surface 42CS of bus bar 42B.

[0131] With this configuration, even when the bus bars 42A and 42B are arranged within a predetermined distance from each other, the insulating rib 53 ensures the necessary insulating distance. This makes it easier to arrange the bus bars 42 close to each other. When the bus bars 42 are arranged close to each other, the size of the electrical connection unit 1 can be reduced. For example, in this embodiment, the insulating rib 53 is located between the side peripheral surface 42CS of the bus bar 42A and the side peripheral surface 42CS of the bus bar 42B in the Y direction. Therefore, providing the insulating rib 53 makes it easier to arrange the bus bars 42A and 42B, which have exposed side peripheral surfaces CS, close to each other.

[0132] (Third embodiment) Next, a third embodiment will be described. The third embodiment differs from the first embodiment in that an insulating wall 95 is provided between two adjacent bus bars 42. Note that the configuration other than that described below is the same as the configuration of the first embodiment.

[0133] FIG. 20 is a perspective view illustrating the insulating wall 95. In this embodiment, the insulating wall 95 is provided between the second surface 51b of the flat portion 51 of the base plate 41 and the flat portion 81 of the metal plate 80. The insulating wall 95 extends in the Z direction, for example, from the second surface 51b of the flat portion 51 of the base plate 41 to the flat portion 81 of the metal plate 80. The insulating wall 95 is made of a synthetic resin and has insulating properties. The insulating wall 95 is formed, for example, by compressing an elastic insulating member between the base plate 41 and the metal plate 80. Similar to the insulating rib 53 of the second embodiment, the insulating wall 95 is arranged between two bus bars 42 that are arranged side by side with their lower surfaces exposed, thereby ensuring an insulating distance between the two bus bars 42.

[0134] Similar to insulating rib 53 of the second embodiment, insulating wall 95 is located between bus bar 42A and bus bar 42B when viewed from the Z direction, and extends in the X direction parallel to bus bar 42A and bus bar 42B. Bus bar 42A, bus bar 42B, and insulating wall 95 may extend linearly in the Y direction instead of the X direction.

[0135] Insulating wall 95 is located between side circumferential surface 42CS of bus bar 42A and side circumferential surface 42CS of bus bar 42B in the Y direction. Insulating wall 95 electrically insulates side circumferential surface 42CS of bus bar 42A from side circumferential surface 42CS of bus bar 42B.

[0136] With this configuration, even when bus bar 42A and bus bar 42B are arranged within a predetermined distance from each other, insulating wall 95 ensures the necessary insulation distance. This makes it easier to arrange multiple bus bars 42 close to each other. When multiple bus bars 42 are arranged close to each other, the electrical connection unit 1 can be made more compact. For example, in this embodiment, insulating wall 95 is located between side circumferential surface 42CS of bus bar 42A and side circumferential surface 42CS of bus bar 42B in the Y direction. Therefore, providing insulating wall 95 makes it easier to arrange bus bar 42A and bus bar 42B, which have exposed side circumferential surfaces CS, close to each other.

[0137] <Modification> Next, several modified examples will be described. Note that in each modified example, the configuration other than that described below is the same as that of the first embodiment.

[0138] (First Modification) The wiring board 40 is not limited to a structure in which the base plate 41 and the bus bar 42 are integrated by insert molding. For example, the base plate 41 may be molded with a housing portion 55 for housing the bus bar 42, and then the bus bar 42 may be placed in the housing portion 55. In this case, the bus bar 42 may be fixed to the housing portion 55 by fitting, or may be fixed to the housing portion 55 by adhesive or other fixing means. In these cases, potting may be applied to fill the gap between the bus bar 42 and the housing portion 55.

[0139] (Second Modification) The base member of the wiring board 40 is not limited to the base plate 41 having the plate-shaped flat portion 51. The wiring board 40 may be a base member (for example, an insulating sheet) having a sheet-shaped flat portion 51. In this case, the housing portion 55 may be formed by a portion of the flat portion 51 conforming to the outer shape of the bus bar 42. In the present disclosure, the term "sheet-shaped" or "sheet" is not limited to a member having a thickness of 1 mm or more, and may also refer to a member having a thickness of less than 1 mm (so-called film).

[0140] (Third Modification) The base plate 41 of the wiring board 40 may include multiple members (plate members or sheet members). The multiple members are arranged to sandwich the multiple bus bars 42 arranged horizontally, for example, from both sides in the Z direction. For example, the multiple members are integrated by sandwiching the multiple bus bars 42, for example, by lamination molding. The multiple members form a planar portion 51. In this case, the accommodating portion 55 may be formed hollow inside the base plate 41 (between the multiple members). The multiple members may be multiple plate members, multiple sheet members, or a combination of plate members and sheet members. The sheet member may be, for example, a flexible sheet member. The planar portion 51 formed by the multiple members has openings that expose at least the first connection portion 61 and the second connection portion 62 of the bus bars 42. In this case, for example, the accommodating portion 55 formed between the multiple members corresponds to an example of an "accommodating portion recessed in the first direction (Z direction)."

[0141] 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. [Explanation of symbols]

[0142] 1...Electrical connection unit SU...subunit 10...Electronic components 13, 13A, 13B...Terminals 20...Connection parts 21…Part 1 21h...First mounting hole 22…Second part 22h: Second mounting hole 30...Connection parts 31…Part 1 32…Second part 40...Wiring board 41...Base plate 42...Busbar 42e1...busbar end 42p…board part 42u…Exposed part 42ua…1st part 42ub…Second part 43... Fastening member (fastening portion) 51...Flat surface portion (insulating base portion) 51a…1st side, 3rd side 51b…2nd side, 4th side 52…Fixed part 52a...first part, third part 52b...Second part, fourth part 55...Storage section 56...Engagement portion 56a...depression 61...First connection part 62...Second connection part 63…Extension part 64...Extension part 71...Fastening member 72...Fastening member 73...Fastening member 80...Metal plate 81…Plane part (metal base) 82…Fixed part 83…Fixed part 92...Heat transfer member 92a...First heat transfer section 92b...Second heat transfer section 100...Connection parts 101…Part 1 102…Second part

Claims

1. a first electronic component; a base member including a plate-like or sheet-like flat portion having a first surface facing the first electronic component and a second surface located on the opposite side to the first surface, wherein when a thickness direction of the flat portion is defined as a first direction, the flat portion has a first housing portion that is recessed in the first direction or that penetrates the flat portion in the first direction; a bus bar electrically connected to the first electronic component, the bus bar including a plate portion accommodated in the first accommodating portion and extending along the first surface, the plate portion including an exposed portion exposed to an outside of the base member on the second surface side; a metal plate having a gap between itself and the flat surface and facing the second surface of the flat surface; a heat transfer member disposed between the exposed portion of the bus bar and the metal plate; Equipped with An electrical connection unit in which a contact surface between the heat transfer member and the exposed portion is closer to the metal plate in the first direction than the second surface.

2. a thickness of the bus bar in the first direction is greater than a thickness of the planar portion in the first direction; The electrical connection unit according to claim 1 .

3. the bus bar is accommodated in the first accommodating portion over the entire length of the bus bar and extends along the flat portion; 3. The electrical connection unit according to claim 1 or 2.

4. the bus bar is accommodated in the first accommodating portion over the entire length of the bus bar and extends along the flat portion, and the bus bar is exposed to the outside of the base member on the second surface side over the entire length of the bus bar; 4. The electrical connection unit according to claim 3.

5. a part of a side peripheral surface of the bus bar facing a direction intersecting the first direction is exposed to an outside of the base member; 3. The electrical connection unit according to claim 1 or 2.

6. The bus bar is integrated with the base member.

3. The electrical connection unit according to claim 1 or 2.

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