Electric connection unit

Abstract

To provide an electric connection unit that can be reduced in weight.SOLUTION: An electric connection unit according to one embodiment includes a circuit structure body, a heat dissipation plate, and one or more heat transfer members. The circuit structure body has a plurality of resistors, and a substrate facing the plurality of resistors. The heat dissipation plate is disposed so as to overlap the circuit structure body in a thickness direction of the substrate, and is formed using a material having higher thermal conductivity than the substrate. The heat transfer member is disposed between the circuit structure body and the heat dissipation plate, and thermally connects the circuit structure body and the heat dissipation plate. At a position on the heat dissipation plate where the heat dissipation plate overlaps the substrate when viewed from the thickness direction but does not overlap at least a part of the heat transfer member, one or more light-weight portions that are thinner than the remaining portion of the heat dissipation plate or that pass through the heat dissipation plate in the thickness direction are formed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Electrical connection units comprising a plurality of electronic components are known. [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, there is a demand for lighter weight electrical connection units.

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

[0006] An electrical connection unit in one embodiment includes a circuit assembly, a heat dissipation plate, and one or more heat transfer members. The circuit assembly includes a plurality of resistors and a substrate facing the plurality of resistors. The heat dissipation plate is disposed so as to overlap the circuit assembly in the thickness direction of the substrate and is formed of a material having better thermal conductivity than the substrate. The heat transfer member is disposed between the circuit assembly and the heat dissipation plate and thermally connects the circuit assembly and the heat dissipation plate. One or more weight-reducing portions are formed thinner than other portions of the heat dissipation plate or penetrate the heat dissipation plate in the thickness direction at positions that overlap the substrate when viewed in the thickness direction but do not overlap at least a portion of the heat transfer member. [Effects of the Invention]

[0007] According to one embodiment, it is possible to provide an electrical connection unit that can be made lighter. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view showing the electrical connection unit according to the embodiment. [Figure 2] FIG. 2 is a perspective view illustrating a main body of the embodiment. [Figure 3] FIG. 2 is a perspective view illustrating a subunit according to the embodiment. [Figure 4] FIG. 2 is a partially exploded perspective view of a subunit according to the embodiment. [Figure 5] FIG. 2 is a perspective view illustrating an electronic component and a connecting component according to the embodiment. [Figure 6] FIG. 2 is a perspective view illustrating an electronic component and a connecting component according to the embodiment. [Figure 7] FIG. 2 is a perspective view showing the wiring board according to the embodiment. [Figure 8] FIG. 2 is a partially exploded perspective view of the wiring board according to the embodiment. [Figure 9] FIG. 5 is a cross-sectional view corresponding to line F9-F9 in FIG. 4. [Figure 10] FIG. 2 is a plan view showing the wiring board according to the embodiment. [Figure 11] FIG. 2 is a partially exploded perspective view of the electrical connection unit according to the embodiment. [Figure 12] FIG. [Figure 13] 11 is a cross-sectional view of the structure shown in FIG. 10 taken along line F13-F13. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the following description, components having the same or similar functions will be assigned the same reference numerals. Duplicate descriptions of those components may be omitted. Note that the specific configurations described below do not limit the applicable 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. "Facing" means that virtual projection images 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 cases where "substantially parallel," "substantially perpendicular," or "substantially 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 "thickness 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] <1. Configuration of the electrical connection unit 1> FIG. 1 is a cross-sectional view showing an electrical connection unit 1 according to an embodiment. 1 is an in-vehicle device mounted on a vehicle such as an EV (Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a PHEV (Plug-in Hybrid Electric Vehicle). The electrical connection unit 1 may also be referred to as an "electrical connection box" or a "junction box." 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 MU> First, the main body MU will be described. FIG. 2 is a perspective view for explaining the main body MU. The main body MU shown in FIG. 2 is a part that performs the main function of the electrical connection unit 1 (for example, switching the electrical connection state or overcurrent protection). The main body MU is divided into, for example, multiple subunits SU. The main body MU is formed, for example, by connecting multiple subunits SU. In this embodiment, the main body MU has three subunits SU (first to third subunits SUX, SUY, SUZ). Each subunit SU may be referred to as a "circuit assembly."

[0016] The first subunit SUX has a first electrical function. The first 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 second subunit SUY has a second electrical function. The second function is different from the first function. The second 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 third subunit SUZ has a third electrical function. The third function is different from the first and second functions. The third 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 first subunit SUX is arranged on the +X direction side of the second subunit SUY. The first subunit SUX and the second subunit SUY are electrically connected via a coupling bus bar 75 that extends between the first routing board 40X and the second routing board 40Y. On the other hand, the third subunit SUZ is arranged on the -X direction side of the second subunit SUY. The third subunit SUZ and the second subunit SUY are electrically connected via a coupling bus bar 75 that extends 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 multiple 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. 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 be given using one subunit SU as a representative. Hereinafter, when the first subunit SUX, the second subunit SUY, and the third subunit SUZ are not distinguished from one another, they will simply be referred to as "subunits SU." Furthermore, when the electronic component 10X, the electronic component 10Y, and the electronic component 10Z are not distinguished from one another, they will simply be referred to as "electronic component 10." Furthermore, when the first routing board 40X, the second routing board 40Y, and the third routing board 40Z are not distinguished from one another, they will simply be referred to as "routing board 40." The routing boards 40, 40X, 40Y, 40Z, and 40M are examples of "boards."

[0022] <3. Structure of the subunit SU> Next, the configuration of the subunit SU will be described. Fig. 3 is a perspective view for explaining the subunit SU, and Fig. 4 is a perspective view showing a part of the subunit SU in an exploded state. As shown in Figures 3 and 4, 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, a wiring board 40, a plurality of fastening members 71, 72, 73, and a connection component 100 for unit connection (see Figure 2).

[0023] <3.1 Electronic component 10 and connecting component 20> First, the electronic component 10 and the connection component 20 will be described. The electronic component 10 is an electronic component that is mounted on the subunit SU according to the functions required of the subunit. 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 examples. 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. The electronic component 10 is an example of a "resistor."

[0024] The connection part 20 is a part that electrically connects the electronic component 10 and the wiring board 40. The connection part 20 forms part of the current path in the subunit SU. The connection part 20 is made of metal (for example, copper or a copper alloy). Below, a first type connection part 20M and a second type connection part 20N will be described as examples of the connection part 20. The connection part 20 is an example of a "resistor."

[0025] <3.1.1 Type 1 Electronic Components 10M> FIG. 5 is a perspective view showing a first type electronic component 10M and a first type connecting component 20M. 5, a first type of electronic component 10M is an electronic component 10 having a plurality of terminals 13 arranged side by side at one end of the electronic component 10M. The electronic component 10M includes, for example, a case 11, a component main body 12, a plurality of terminals 13, and a plurality of mounting portions 14.

[0026] (Case 11) 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.

[0027] In this embodiment, the case 11 has an insulating rib 11a that protrudes in the 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 arranged between multiple terminals 13. The insulating rib 11a provides electrical insulation between adjacent terminals 13. In this embodiment, a portion of the insulating rib 11a is arranged between two connection parts 20M connected to the electronic component 10M. The insulating rib 11a provides electrical insulation between the two connection parts 20M connected to the electronic component 10M.

[0028] (Component body 12) 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.

[0029] (Terminal 13) The terminal 13 is an electrical connection portion exposed to the outside of the case 11. The terminal 13 is electrically connected to the component main body 12 inside the case 11. In this embodiment, there are multiple terminals 13. One of the multiple terminals 13 is a positive terminal 13. The other of the multiple terminals 13 is a negative terminal 13.

[0030] The multiple terminals 13 are provided at one end of the electronic component 10M in the horizontal direction (e.g., the X direction). The terminals 13 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) is attached. The mounting hole 13h opens in the horizontal direction (e.g., the X direction). The inner circumferential surface of the mounting hole 13h of the electronic component 10M has a threaded groove.

[0031] (Mounting part 14) The mounting portion 14 is a portion for fixing the electronic component 10M. The mounting portion 14 has a mounting hole 14h to which a fastening member 112 (e.g., a screw or a bolt, see FIG. 11) is attached. The mounting hole 14h penetrates the mounting portion 14 in the Z direction. The mounting hole 14h is an insertion hole through which the fastening member 112 is passed. The destination to which the mounting portion 14 is fixed will be described later.

[0032] <3.1.2 Type 1 connecting part 20M> The first type connecting part 20M is a part that electrically connects the first type electronic component 10M and the wiring board 40. In the present 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. The connecting part 20M has, for example, a first portion 21 and a second portion 22.

[0033] (Part 1 21) The first portion 21 of the connecting part 20M is a portion that is connected to the terminal 13 of the electrical component 10M. The first portion 21 is a plate-like or rectangular column-like 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).

[0034] 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 opens in the horizontal direction (e.g., the X direction). The fastening member 71 passed through the first mounting hole 21h engages with the electronic component 10M inside the mounting hole 13h of the terminal 13, thereby physically and electrically connecting the first portion 21 to the terminal 13 of the electronic component 10M.

[0035] (Second part 22) 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 in the horizontal direction (e.g., 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, thereby being 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. An engaging member 44 (for example, a nut shown in 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.

[0036] <3.1.3 Second type electronic component 10N> FIG. 6 is a perspective view showing a second type electronic component 10N and a second type connecting component 20N. As shown in FIG. 6, 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 has, 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 that have 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 above description of the electronic component 10M.

[0037] In the electronic component 10N, the terminals 13 are arranged separately at both ends of the 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) is attached. The mounting hole 13h penetrates each terminal 13 in the Z direction. For example, the mounting hole 13h of the electronic component 10N is an insertion hole through which the fastening member 72 is passed.

[0038] <3.1.4 Second type connecting part 20N> The second type connecting part 20N is a part that electrically connects the second type electronic component 10N to the wiring board 40. In this embodiment, the connecting part 20N electrically connects the electronic component 10N to a bus bar 42 (see FIG. 8) included in the wiring board 40. The connecting part 20N has, for example, a first part 21, a second part 22, and a third part 23.

[0039] (Part 1 21) The first portion 21 of the connecting part 20N is a portion that is connected to the terminal 13 of the electronic component 10N. The first portion 21 is a rectangular column-shaped portion that extends in the Z direction. The first portion 21 is an upright portion that stands in the Z direction relative to the wiring 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 connecting part 20N has a first mounting hole 21h that engages with the fastening member 72. The first mounting hole 21h opens on the +Z direction side of the first portion 21. The inner circumferential surface of the first mounting hole 21h of the connecting part 20N has a thread groove. The first part 21 is physically and electrically connected to the terminal 13 of the electronic component 10N by the fastening member 72 passing through the mounting hole 13h of the electronic component 10N engaging with the first part 21 within the mounting hole 21h of the first part 21.

[0040] (Second part 22) 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, thereby being 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 penetrates the second part 22 in the Z direction. The fastening member 43 is passed through the second mounting hole 22h of the second part 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.

[0041] (Part 3 23) 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. On the other hand, the connection part 20N may not have the third portion 23.

[0042] <3.2 External connection parts 30> Next, the connecting part 30 for external connection will be described. As shown in Figures 3 and 4, the connection part 30 is a part that electrically connects the external connection bus bar 76 and the wiring board 40. In this embodiment, the connection part 30 electrically connects the external connection bus bar 76 and the bus bar 42 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 the external device include a battery unit mounted on a vehicle or an inverter for driving a vehicle motor. However, the external device is not limited to a battery unit or an inverter. The bus bar 42 is an example of a "resistor."

[0043] Like the connection component 20, the connection component 30 is made of metal (for example, copper or a copper alloy). As shown in FIG. 2, the connection component 30 is provided in an upright state on the +Z direction side at the outer periphery (X direction end) of the wiring board 40M. A first end (-Z direction end) of the connection component 30 is connected to the bus bar 42 by a fastening member 43 (for example, a bolt). A second end (+Z direction end) of the connection component 20 is connected to the external connection bus bar 76 by a fastening member 73 (for example, a screw or a bolt).

[0044] <3.3 Connection parts 100 for unit connection> Next, the connecting part 100 for connecting units will be described. 2, the connection part 100 electrically connects adjacent subunits SU to each other. In this embodiment, the connection part 100 connects between the bus bar 42 included in one of the adjacent subunits SU (for example, the second subunit SUY) and the bus bar 42 included in the other subunit SU (for example, the third subunit SUZ).

[0045] <3.4 Wiring board 40> First, the wiring board 40 will be described. FIG. 7 is a perspective view showing the wiring board 40. As shown in FIG. As shown in FIG. 7 , the wiring board 40 is a member 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 as a whole, 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 has a fixing structure or rib protruding in the Z direction or an uneven surface that conforms to the thickness of the bus bar. In this embodiment, the wiring board 40 is a plate-like structure that is flat along the X and Y directions.

[0046] 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 using another structure instead of insert molding.

[0047] 8 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.

[0048] (Base plate 41) As shown in FIG. 8 , the base plate 41 is a holding member that integrally holds a plurality of bus bars 42 that are arranged horizontally at intervals from one another. The base plate 41 is made of, for example, a synthetic resin and has insulating properties. The base plate 41 is formed, for example, in a rectangular shape with the X direction as the longitudinal direction and the Y direction as the lateral direction. The base plate 41 electrically insulates the plurality of bus bars 42 from one another. The base plate 41 has, for example, a flat portion 51 and a plurality of fixing portions 52.

[0049] The flat surface portion 51 is a plate-shaped portion of the base plate 41. The flat surface portion 51 forms the main portion of the base plate 41. The flat surface portion 51 extends in the horizontal direction. 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 corners of the base plate 41.

[0050] 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.

[0051] The flat portion 51 is formed with one or more (e.g., multiple) accommodating portions 55, each accommodating a bus bar 42, for example. 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 penetrating the flat portion 51 in the Z direction. That is, each accommodating portion 55 is open in the Z direction on both the first surface 51a and the second surface 51b. Note that instead of a through-hole, the accommodating portion 55 may be a recess 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 "the 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 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).

[0052] 8, when viewed from the Z direction, each accommodating portion 55 is formed to have an outer shape corresponding to the shape of the bus bar 42 to be accommodated. In the present embodiment, the planar portion 51 includes, as the plurality of accommodating portions 55, for example, five accommodating portions 55A, 55B, 55C, 55D, and 55E.

[0053] A through hole 51h is formed in the flat portion 51 at a position offset in the X direction or Y direction from the accommodation portion 55. As shown in FIG. 4 , the through hole 51h is formed at a position overlapping, for example, the mounting portion 14 of the electronic component 10 when viewed from the Z direction. The mounting portion 14 is a portion for mounting the electronic component 10 to the metal plate 80. The mounting portion 14 protrudes in the X direction or Y direction from the end of the case of the electronic component 10 on the −Z direction side.

[0054] FIG. 9 is a cross-sectional view taken along line F9-F9 in FIG. 4 and 9, the fixing portion 52 is a portion used to fix the metal plate 80 to the base plate 41. The fixing portion 52 is provided at a corner of the base plate 41. The fixing portion 52 includes, for example, an upright plate portion 52a and a horizontal plate portion 52b.

[0055] The standing plate portion 52a stands upright in the +Z direction from an end of the flat portion 51 of the base plate 41. When viewed from the Z direction, the standing plate portion 52a is formed, for example, in an L shape. That is, the standing plate portion 52a extends in the Z direction with a portion of the horizontal direction open. The horizontal plate portion 52b extends horizontally from the end of the upright plate portion 52a on the +Z direction side. The horizontal plate portion 52b is a plate portion that extends horizontally. The horizontal plate portion 52b extends like an eave so as to cover the area surrounded by the upright plate portion 52a from the +Z direction side.

[0056] (Busbar 42) As shown in FIGS. 5 and 6 , busbars 42 are routing members (electrical connection members) included in routing board 40. Busbars 42 are, for example, routing members for electrically connecting multiple electronic components 10 together. Busbars 42 may also be routing members for connecting one electronic component 10 to an external device. Busbars 42 are made of metal (for example, copper or a copper alloy) and are electrically conductive. In this embodiment, routing board 40 has 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 are held by flat portion 51 of base plate 41.

[0057] At least a portion of each bus bar 42 is a plate-like shape extending in the horizontal direction. At least a portion of each bus bar 42 extends along the flat portion 51 while housed in the housing portion 55. At least a portion of each bus bar 42 extends along the first surface 51a of the flat portion 51. At least a portion of each bus bar 42 extends in the horizontal direction within the housing portion 55. In the present embodiment, each bus bar 42 is a plate-like shape extending in the horizontal direction over the entire bus bar 42. Each bus bar 42 extends along the flat portion 51 while housed in the housing portion 55 over the entire length of the bus bar 42. Hereinafter, the portion of each bus bar 42 housed in the housing portion 55 (the portion extending along the flat portion 51) may be referred to as the "plate portion 42p."

[0058] FIG. 10 is a plan view showing the wiring board 40. As shown in FIG. As shown in FIG. 10, 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.

[0059] The first connection portion 61 is a portion that contacts one of the multiple connection components 20 (hereinafter referred to as the "first connection component 20"). The first connection component 20 is a connection component that connects one of the multiple electronic components 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. The first connection portion 61 is connected to the first connection component 20 from the Z direction.

[0060] The second connection portion 62 is a portion that comes into contact with a connection portion 20 (hereinafter referred to as the "second connection portion 20") different from the first connection portion 20 among the multiple connection portions 20. The second connection portion 20 is a connection portion that connects an electronic component 10 (hereinafter referred to as the "second electronic component 10") different from the first electronic component 10 among the multiple 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 portion 20 when viewed from the Z direction. The second connection portion 62 is adjacent to the second connection portion 20 in the Z direction. The second connection portion 62 is connected to the second connection portion 20 from the Z direction.

[0061] The second connection portion 62 may be a portion that comes into contact with the connection component 30. The connection component 30 is a connection component for connecting an external device and the bus bar 42. In this case, the second connection portion 62 is a portion of the bus bar 42 that overlaps with the connection component 30 when viewed from the Z direction. The second connection portion 62 is adjacent to the connection component 30 in the Z direction. The second connection portion 62 is connected to the connection component 30 from the Z direction.

[0062] The second connection portion 62 may be a portion that contacts the coupling bus bar 75 for connecting to another subunit SU, instead of the connection parts 20, 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. The second connection portion 62 is connected to the coupling bus bar 75 from the Z direction.

[0063] 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.

[0064] In this embodiment, the first connection portion 61, the second connection portion 62, and the extension portion 63 are plate-shaped and extend horizontally. In this embodiment, each busbar 42 extends along the flat portion 51 while being housed in the housing portion 55, spanning at least the first connection portion 61 and the second connection portion 62. For example, the first connection portion 61, the second connection portion 62, and the extension portion 63 extend along the flat portion 51 while being housed in the housing portion 55. The portion of each busbar 42 housed in the housing portion 55 is exposed on the first surface 51a and the second surface 51b of the flat portion 51. That is, the surface of each busbar 42 facing the Z direction is exposed to the outside of the base plate 41 (e.g., in the +Z direction and the −Z direction) through the opening of the housing portion 55. However, a portion of the busbar 42 may be buried in the base plate 41.

[0065] In this embodiment, the extension portions 63 of some bus bars 42 are accommodated in the accommodation portion 55, and extend through the region R that overlaps with the electronic component 10 when viewed from the Z direction, so as to span both sides of the region R. For example, the extension portions 63 extend linearly in 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, so as to span both the +X direction side and the −X direction side of the region R.

[0066] 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 extends along the flat portion 51 when housed in the housing portion 55. When housed in the housing portion 55, the extension portion 64 extends to a region R that overlaps with the electronic component 10 when viewed from the Z direction. The extension portion 64 has an end 42e1 of the bus bar 42 at a position that overlaps with the region R when viewed from the Z direction.

[0067] The following describes several examples of wiring the bus bars 42. The plurality of electronic components 10 includes three electronic components 10A, 10B, and 10C. The plurality of connection components 20 includes six connection components 20A, 20B, 20C, 20D, 20E, and 20F. The plurality of connection components 30 includes two connection components 30A and 30B.

[0068] (1st wiring example) First, an example of wiring of the bus bar 42A will be described. The 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, the first connection portion 61 is located on the +X direction side of the electronic component 10A. The first connection portion 61 is electrically connected to a terminal 13 (e.g., a positive terminal: see FIG. 5) of the electronic component 10A via a connection part 20A. The second connection portion 62 is located on the −X direction side of the electronic component 10A when viewed from the Z direction. The second connection portion 62 is electrically connected to another subunit SU via a coupling bus bar 75.

[0069] 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 in the X direction. Extension portion 63 extends through region R that overlaps with electronic component 10A when viewed from the Z direction, so as to span both the +X direction side and the −X direction side of region R. Bus bar 42A is, for example, a bus bar included in positive electrode line PL of electrical connection unit 1.

[0070] (Second wiring example) Next, an example of wiring of the bus bar 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 13 (e.g., a negative terminal: see FIG. 5 ) of the electronic component 10A via a connection part 20B different from the first connection part 20. The second connection portion 62 is electrically connected to an external connection busbar 76 via a connection part 30A. The extension portion 64 extends to a region R that overlaps with the electronic component 10A when viewed from the Z direction. The extension portion 64 has an end 42e1 of the busbar 42 at a position that overlaps with the region R when viewed from the Z direction. Note that, like the extension portion 63 of the busbar 42A, the extension portion 63 of the busbar 42B may extend to both sides of the region R through the region R that overlaps with the electronic component 10A when viewed from the Z direction. The busbar 42B is, for example, a busbar included in a positive line PL of the electrical connection unit 1.

[0071] (3rd wiring example) Next, an example of wiring of the bus bar 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 13 (e.g., a negative terminal: see FIG. 5) of the electronic component 10B via a connection part 20C. The second connection portion 62 is electrically connected to another subunit SU via a coupling busbar 75. The extension portion 64 extends to a region R that overlaps with the electronic component 10B when viewed from the Z direction. The extension portion 64 has an end 42e1 of the busbar 42 at a position that overlaps with the region R when viewed from the Z direction. The busbar 42C is, for example, a busbar included in a negative line NL of the electrical connection unit 1.

[0072] (4th wiring example) Next, an example of wiring of the bus bar 42D will be described. Busbar 42D has a first connection portion 61, a second connection portion 62, and an extension portion 63. First connection portion 61 is electrically connected to terminal 13 (e.g., positive terminal: see FIG. 5) of electronic component 10B via connection part 20D. Second connection portion 62 is electrically connected to terminal 13 (e.g., negative terminal: see FIG. 6) of electronic component 10C via connection part 20E. Busbar 42D is, for example, a busbar included in negative line NL of electrical connection unit 1.

[0073] (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 13 (e.g., a negative terminal: see FIG. 6 ) of the electronic component 10C via a connection part 20F. The second connection portion 62 is electrically connected to an external connection bus bar 76 via a connection part 30B. The bus bar 42E is, for example, a bus bar included in a negative line NL of the electrical connection unit 1. In this embodiment, the electronic component 10C (the second-type electronic component 10N) is bridged between the connection parts 20D and 20F (the second-type connection parts 20N). Specifically, as shown in FIGS. 6 and 10 , both terminals 13 of the electronic component 10C are supported by the first portion 21 from the +Z direction side, and thus the case 11 of the electronic component 10C is supported by the connection parts 20D and 20F with the case 11 spaced apart from the wiring board 40 in the Z direction.

[0074] (Fastening member 43) Next, returning to FIG. 8, the fastening member 43 will be described. The fastening member 43 is a component for fastening the bus bar 42 to a component to which the bus bar 42 is connected (connection component 20, connection component 30, or coupling bus bar 75). The fastening member 43 is, for example, a crimp bolt fixed to the bus bar 42. The fastening member 43 penetrates the bus bar 42 in the Z direction. The fastening member 43 is electrically and physically connected to the bus bar 42 while protruding in the +Z direction relative to the bus bar 42. 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] The connection component 20 is first fixed to the electronic component 10 by the fastening member 71 or the fastening member 72, and then fixed to the fastening member 43. For example, the fastening member 43 penetrates the second portion 22 of the connection component 20 (see FIGS. 5 and 6 ). As shown in FIG. 3 , an engaging member 44 (e.g., a nut) is attached to the portion of the fastening member 43 that protrudes in the +Z direction relative to the connection component 20. This attachment mounts the connection component 20 to the wiring board 40. Note that in this disclosure, "an electronic component is mounted on a board" does not mean that the electronic component is directly connected to the board, but also includes the case where the electronic component is connected to the board via another component (e.g., the connection component 20). Also, in this disclosure, "an electronic component is mounted on a board" means that at least the electronic component is electrically connected to the board, and also includes the case where the electronic component is fixed to a member other than the board (e.g., a metal plate 80) instead of or in addition to the board.

[0076] <4. Connection structure> Next, the connection structure of the subunits SU will be described. 2, the first subunit SUX, the second subunit SUY, and the third subunit SUZ are arranged in order from the +X direction side to the -X direction side. The first subunit SUX and the second subunit SUY are electrically connected via a connecting bus bar 75A. The second subunit SUY and the third subunit SUZ are electrically and physically connected via a connecting bus bar 75B.

[0077] Adjacent subunits SU are arranged with their ends facing each other in the X direction overlapping in the Z direction. Specifically, the fixed portion 52 (horizontal plate portion 52b) located on the -X direction side of the first subunit SUX is overlapped from the +Z direction by the fixed portion 52 (horizontal plate portion 52b) located on the +X direction side of the second subunit SUY. The fixed portion 52 (horizontal plate portion 52b) located on the +X direction side of the third subunit SUX is overlapped from the +Z direction by the fixed portion 52 (horizontal plate portion 52b) located on the -X direction side of the second subunit SUY.

[0078] <5. Metal Plate 80, Insulating Sheet 91, Heat Transfer Member 92, and Insulating Cover 93> Next, the metal plate 80, the insulating sheet 91, the heat transfer member 92, and the insulating cover 93 will be described.

[0079] <5.1 Metal Plate 80> FIG. 11 is a perspective view showing the electrical connection unit 1 in a partially exploded state. As shown in FIG. 11 , the metal plate 80 is a member that ensures the rigidity of the electrical connection unit 1 and also enhances the heat dissipation 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 is an example of a "heat dissipation plate." The heat dissipation plate is not limited to metal, and various materials can be used as long as they have superior thermal conductivity compared to the base plate 41, for example.

[0080] 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 longitudinal ends 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 lateral ends of the metal plate 80 and are spaced apart in the Y direction. In this embodiment, the metal plate 80 is large enough to cover the entire three subunits SU (main body portions MU) from below. Specifically, the length of the metal plate 80 in the X direction is greater than the length of the main body portion MU in the X direction. The length of the metal plate 80 in the Y direction is greater than the length of the main body portion MU in the Y direction. Therefore, when viewed from the Z direction, the area of ​​the metal plate 80 is greater than the area of ​​the main body portion MU.

[0081] The metal plate 80 includes, for example, a flat portion 81, a plurality of fixing portions 82, a plurality of fixing portions 83, and a peripheral wall portion 84.

[0082] The flat surface portion 81 is a plate-shaped portion of the metal plate 80. The flat surface portion 81 is a plate-shaped portion extending 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 entire three subunits SU (main body portions MU) from below. The flat surface portion 81 faces the wiring board 40 of the three subunits SU. In this embodiment, the metal plate 80 faces the second surface 51b of each subunit SU with a gap S1 (see FIG. 9 ) between the flat surface portion 81 and the second surface 51b of each subunit SU. Note that a mounting flange or the like for mounting to an external device may be provided on the outer periphery of the flat surface portion 81 (at a position that does not overlap with the wiring board 40 when viewed from the Z direction).

[0083] 9 and 11, the fixing portion 82 is a 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 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.

[0084] The fixing portion 83 is a 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 in the +Z direction from the flat portion 81. The amount of protrusion of the fixing portion 83 in the Z direction is smaller than the amount of protrusion of the fixing portion 82 in the Z direction.

[0085] 2, the peripheral wall portion 84 extends in the +Z direction from the outer peripheral edge of the flat portion 81. The peripheral wall portion 84 extends around the entire periphery of the flat portion 81. The length of the peripheral wall portion 84 in the Z direction is shorter than the length of the fixing portions 82, 83 in the Z direction.

[0086] <5.2 Insulation sheet 91> 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 is provided so as to cover the entire flat portion 81 of the metal plate 80 from the +Z direction side. Therefore, the main body portion MU faces the metal plate 80 with the insulating sheet 91 sandwiched therebetween.

[0087] The insulating sheet 91 is attached to the flat portion 81 of the metal plate 80. The insulating sheet 91 has cutouts or openings formed therein to avoid the fixing portions 82 and 83 of the metal plate 80. In this embodiment, the thickness of the insulating sheet 91 in the Z direction is thinner than the thickness of the peripheral wall portion 84 in the Z direction. Therefore, the insulating sheet 91 is positioned horizontally relative to the metal plate 80 by being surrounded by the peripheral wall portion 84.

[0088] <5.3 Heat Transfer Material 92> 9, the heat transfer member 92 is a member for transferring heat generated by the electronic component 10 when current is applied and / or 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). 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 materials.

[0089] The multiple heat transfer members 92 include, for example, one or more (e.g., multiple) heat transfer members 92 corresponding to the first subunit SUX, one or more (e.g., multiple) heat transfer members 92 corresponding to the second subunit SUY, and one or more (e.g., multiple) heat transfer members 92 corresponding to the third subunit SUZ. The heat transfer member 92 corresponding to the first subunit SUX is arranged at a position overlapping the first subunit SUX when viewed from the Z direction, and transfers heat generated by the first subunit SUX to the metal plate 80. The heat transfer member 92 corresponding to the second subunit SUY is arranged at a position overlapping the second subunit SUY when viewed from the Z direction, and transfers heat generated by the second subunit SUX to the metal plate 80. The heat transfer member 92 corresponding to the third subunit SUZ is arranged at a position overlapping the third subunit SUZ when viewed from the Z direction, and transfers heat generated by the third subunit SUZ to the metal plate 80.

[0090] FIG. 12 is a bottom view showing the wiring board 40. As shown in FIG. 12 , the heat transfer members 92 transfer heat transferred from the electronic component 10 to the bus bar 42 and / or heat generated in the bus bar 42 from the bus bar 42 to the metal plate 80. The heat transfer members 92 are provided partially on the wiring board 40 in the horizontal direction. For example, the heat transfer members 92 are arranged in positions on the wiring board 40 that overlap with portions of the bus bar 42 when viewed from the Z direction. The heat transfer members 92 are arranged in positions that overlap with portions of the bus bar 42 near the electronic component 10 (e.g., electronic components 10A and 10B) when viewed from the Z direction. In this embodiment, the heat transfer members 92 are arranged in positions that overlap with the connecting part 20 (the connection portion between the bus bar 42 and the electronic component 10) when viewed from the Z direction.

[0091] FIG. 13 is a cross-sectional view of the structure shown in FIG. 10 taken along line F13-F13. 13 , the heat transfer member 92 is disposed in a crushed state between the main body MU and the insulating sheet 91 in the Z direction. A portion of the heat transfer member 92 located on the −Z direction side is in contact with the metal plate 80 via the insulating sheet 91. The heat transfer member 92 may be disposed between the insulating sheet 91 and the metal plate 80.

[0092] A portion of the heat transfer member 92 located on the +Z direction side is in contact with the bus bar 42. In the present embodiment, the heat transfer member 92 is in contact with the bus bar 42 at a position overlapping with the connection part 20 when viewed from the Z direction. In this case, the heat transfer member 92 facilitates the transfer of heat from the electronic component 10 to the connection part 20 from the connection part 20 to the metal plate 80 via the bus bar 42. A portion of the heat transfer member 92 is disposed in a position overlapping with the fastening member 43 when viewed from the Z direction, and is in contact with the fastening member 43. In this case, the heat transfer member 92 facilitates the transfer of heat from the electronic component 10 to the connection part 20 from the fastening member 43 to the metal plate 80.

[0093] In this embodiment, a portion of the heat transfer member 92 contacts the bus bar 42 at a position that overlaps with the electronic component 10 when viewed from the Z direction. In this case, the heat transfer member 92 makes it easier to transfer heat 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. 11 , 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. The electronic component 10, the connection part 20, and the bus bar 42 are examples of a "first resistor."

[0094] <5.4 Insulation cover 93> Returning to FIG. 1, the insulating cover 93 will be described. The insulating cover 93 is a member for ensuring the safety of the electrical 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 -Z side. The insulating cover 93 is attached to the metal plate 80 so as to cover the main body unit MU from the +Z side. In this embodiment, a plurality of ventilation holes 93h are formed in the top wall of the insulating cover 93. Note that the insulating cover 93 is not limited to a box-shaped member, and may be a sheet-shaped member that covers the electrical paths of the main body unit MU.

[0095] <6. Fixed structure> Next, the anchoring structure of the subunit SU will be described. 7, the main body MU is stacked in the Z direction on the metal plate 80 with the fixing portions 52 of adjacent subunits SU overlapping with the fixing portions 82 of the metal plate 80. The fixing portions 52, 82 overlapping in the Z direction are fixed to each other by fastening members 111 (e.g., screws or bolts). The fastening members 111 pass through the fixing portions 52 of the subunits SU and are then fastened to the fixing portions 82 of the metal plate 80.

[0096] With the main body portion MU and the metal plate 80 stacked together, the fixing portion 83 of the metal plate 80 passes through the through hole 51h of the subunit SU. The mounting portion 14 of the electronic component 10 is overlapped in the Z direction on the fixing portion 83. The mounting portion 14 and the fixing portion 83 that overlap in the Z direction are fixed to each other by a fastening member 112 (e.g., a screw or a bolt). The fastening member 112 passes through the mounting portion 14 and is then fastened to the fixing portion 83 of the metal plate 80. A gap is provided between the inner circumferential surface of the through hole 51h and the fixing portion 83 to allow air to pass through.

[0097] <7. Lightweight part 88> Next, the weight-reducing portion 88 formed on the metal plate 80 will be described. 11, one or more (for example, a plurality of) weight-reducing portions 88 are formed in a portion of the flat portion 81 of the metal plate 80 that avoids the fixing portions 82 and 83. As shown in Fig. 9, the weight-reducing portions 88 are through-holes that penetrate the flat portion 81 in the Z direction.

[0098] A weight-reducing portion 88 is provided corresponding to each subunit SU. That is, the weight-reducing portions 88 are provided on the metal plate 80 at positions that overlap with the respective subunits SU when viewed from the Z direction. In this embodiment, the weight-reducing portions 88 are lined up at intervals in the X direction on both ends of the metal plate 80 in the Y direction. In the following explanation, the weight-reducing portions 88 will be described in detail using the weight-reducing portion 88 provided corresponding to the first subunit SUX as an example.

[0099] 12, each weight-reducing portion 88 is formed in a position on the planar portion 81 that overlaps with the wiring board 40 but does not overlap with at least a portion of the heat-transfer member 92, as viewed from the Z direction. In this embodiment, each weight-reducing portion 88 is provided at a position offset from the entire heat-transfer member 92, as viewed from the Z direction. Each weight-reducing portion 88 includes weight-reducing portions 88A and 88B. The weight-reducing portions 88A and 88B are arranged spaced apart from each other in the horizontal direction.

[0100] 9 and 10 , the weight-reduced portion 88A is provided at a position on the flat portion 81 that overlaps with the bus bar 42A when viewed from the Z direction. In the present embodiment, a portion of the weight-reduced portion 88A overlaps with the extension portion 63 when viewed from the Z direction. That is, a portion of the weight-reduced portion 88A overlaps with the bus bar 42A, and the remainder overlaps with the flat portion 51. However, the entire weight-reduced portion 88A may overlap with the bus bar 42A or the flat portion 51.

[0101] The weight-reduced portion 88A is formed in a rectangular shape with the longitudinal direction in the X direction and the lateral direction in the Y direction when viewed from the Z direction. The weight-reduced portion 88A extends linearly along the extension direction of the bus bar 42A (extension portion 63). The length of the weight-reduced portion 88A in the X direction is shorter than the length of the bus bar 42A in the X direction. The width of the weight-reduced portion 88A in the Y direction is narrower than the width of the extension portion 63 in the Y direction. However, the dimensions and shape of the weight-reduced portion 88A can be changed as appropriate.

[0102] As shown in FIGS. 10 and 13 , the weight-reduced portion 88B is provided at a position on the planar portion 81 that overlaps with the electronic component 10C and the connecting components 20E and 20F when viewed from the Z direction. The weight-reduced portion 88B is formed in a rectangular shape with the X direction as the longitudinal direction and the Y direction as the lateral direction when viewed from the Z direction. In this embodiment, the weight-reduced portion 88B is formed to a size that covers the entire electronic component 10C and the connecting components 20E and 20F when viewed from the Z direction. That is, the width of the weight-reduced portion 88B in the Y direction is wider than the widths of the electronic component 10C and the connecting components 20E and 20F in the Y direction. The length of the weight-reduced portion 88B in the X direction is longer than the length of the electronic component 10C and the connecting components 20E and 20F in the X direction. However, the dimensions and shape of the weight-reduced portion 88B can be changed as appropriate.

[0103] The area of ​​each weight-reducing portion 88 as viewed from the Z direction is larger than the area of ​​each heat-transfer member 92 as viewed from the Z direction. In this embodiment, the total area of ​​the weight-reducing portions 88 (weight-reducing portions 88A, 88B) provided corresponding to the first subunit SUX is larger than the total area of ​​the heat-transfer members 92 provided corresponding to the first subunit SUX. However, the area of ​​the weight-reducing portions 88 may be smaller than the area of ​​the heat-transfer members 92.

[0104] In the present embodiment, the area of ​​the weight-reduced portion 88 within the entire metal plate 80 (flat portion 81) may be set according to the heat capacity, etc., of the metal plate 80. That is, the greater the amount of heat generated by the electronic component 10 or the bus bar 42, the smaller the area of ​​the weight-reduced portion 88 may be made to ensure the heat capacity of the metal plate 80 as a heat dissipation plate.

[0105] 8. Heat Transfer 11 , the subunit SU generates heat, for example, when current is applied to the electronic component 10 or the bus bar 42. Of the heat generated in the subunit SU, part of the heat from the base plate 41 is transferred to the metal plate 80 (flat portion 81) via the heat transfer member 92 and the insulating sheet 91. Part of the heat from the base plate 41 is transferred to the fixing portion 82 of the metal plate 80 via the fixing portion 52. Part of the heat from the electronic component 10 is transferred to the fixing portion 83 of the metal plate 80 via the mounting portion 14. In this way, the heat generated in the subunit SU is transferred to the metal plate 80 and then released from the metal plate 80 to the outside.

[0106] Here, the warm air that has accumulated in the gap S1 between the metal plate 80 and the base plate 41 is released to the outside of the electrical connection unit 1 through the weight-reducing portion 88. This promotes heat dissipation from the electrical connection unit 1.

[0107] In the electrical connection unit 1 of this embodiment, one or more weight-reducing portions 88 that penetrate the metal plate 80 in the Z direction are formed at positions on the metal plate 80 that overlap the subunit SU when viewed from the Z direction but do not overlap at least a portion of the heat transfer member 92. According to this configuration, the weight-reduced portion 88 is formed on the metal plate 80, which allows the weight of the metal plate 80 to be reduced compared to when the entire metal plate 80 is formed with a uniform thickness. This configuration allows the weight of the electrical connection unit 1 to be reduced. Meanwhile, a heat transfer member 92 that thermally connects the subunit SU and the metal plate 80 is provided on the metal plate 80 at a position that does not overlap with the weight-reduced portion 88 when viewed from the Z direction. This allows heat generated in the subunit SU to be effectively transferred to the metal plate 80. Furthermore, because the weight-reduced portion 88 penetrates the metal plate 80 in the Z direction, it is possible to prevent heat from being trapped between the metal plate 80 and the subunit SU. This configuration also improves the heat dissipation performance of the electrical connection unit 1.

[0108] In this embodiment, the heat transfer member 92 is provided at a position where it overlaps with the bus bar 42 when viewed from the Z direction. According to this configuration, bus bar 42, which is one of the heat-generating parts of subunit SU, and metal plate 80 are thermally connected via heat transfer member 92. This connection can further improve heat dissipation.

[0109] In this embodiment, a plurality of weight-reducing portions 88 are arranged spaced apart from one another in the horizontal direction. According to this configuration, the layout flexibility of the light-weight portion 88 can be improved compared to when one large light-weight portion 88 is formed.

[0110] In this embodiment, the area of ​​the weight-reduced portion 88 is larger than the area of ​​the heat transfer member 92 when viewed from the Z direction. According to this configuration, the area of ​​the weight-reduced portion 88 can be secured, and the weight of the electrical connection unit 1 can be further reduced.

[0111] In this embodiment, the electronic component 10 (electronic component 10C) is supported by connection parts 20 (connection parts 20E, 20F) at a distance from the wiring board 40 in the Z direction, and is electrically connected to the bus bar 42 via the connection parts 20. The weight-reduced portion 88 (weight-reduced portion 88B) is provided at a position overlapping the electronic component 10 when viewed from the Z direction. According to this configuration, since the electronic component 10 is disposed away from the wiring board 40, heat is less likely to be transmitted directly downward from the electronic component 10. Furthermore, by providing the weight-reduced portion 88 in a location where heat from the electronic component 10 is less likely to be transmitted directly downward, it is possible to suppress a decrease in heat dissipation performance due to weight reduction. Furthermore, since a load is less likely to be applied to the periphery of the weight-reduced portion 88 via the electronic component 10, it is easier to ensure the strength reliability of the metal plate 80.

[0112] <9. Other Modifications> Next, several modified examples will be described. Note that the configuration of each modified example is the same as that of the above embodiment except for the configuration described below.

[0113] (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.

[0114] (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 accommodation portion 55 may be formed by a portion of the flat portion 51 conforming to the outer shape of the bus bar 42. In this 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).

[0115] (Third Modification) The base plate 41 of the wiring board 40 may include a plurality of members (plate members or sheet members). The plurality of members are arranged to sandwich the plurality of bus bars 42 arranged horizontally, for example, from both sides in the Z direction. For example, the plurality of members are integrated by sandwiching the plurality of bus bars 42, for example, by lamination molding. The plurality of members form a planar portion 51. In this case, the accommodating portion 55 may be formed hollow inside the base plate 41 (between the plurality of members). The plurality of members may be a plurality of plate members, a plurality of 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 plurality of members has openings that expose at least the first connection portion 61 and the second connection portion 62 of the bus bars 42. For example, in this case, the accommodating portion 55 formed between the plurality of members corresponds to an example of an "accommodating portion recessed in the first direction (Z direction)."

[0116] (Fourth Modification) The connection between the electronic component 10 and the bus bar 42 is not limited to the connection via the connection component 20. The electronic component 10 may be directly connected to the bus bar 42 using a fastening member (for example, a bolt or a screw), welding, or the like.

[0117] Several embodiments and modifications have been described above. However, the embodiments and modifications are not limited to the above examples. For example, multiple embodiments may be realized in combination with each other. The present invention is not limited by the above description, but is limited only by the scope of the accompanying claims. In the above embodiment, the electrical connection unit 1 for a vehicle has been described, but the present invention is not limited to this configuration. In the above-described embodiment, an example in which the main body MU is configured by a plurality of subunits SUX, SUY, and SUZ has been described, but this configuration is not limiting. The electrical connection unit 1 may also be configured by a single circuit structure. In the above-described embodiment, the metal plate 80 is used as an example of the heat dissipation plate, but the present invention is not limited to this configuration. The heat dissipation plate may be made of any material having a higher thermal conductivity than the wiring board 40.

[0118] In the above embodiment, the metal plate 80 is configured to overlap the entire main body portion MU, but the present invention is not limited to this configuration. The metal plate 80 only needs to overlap at least a portion of the main body portion MU. In the above-described embodiment, a configuration in which a plurality of weight-reducing portions 88 are provided has been described, but the present invention is not limited to this configuration. In the above-described embodiment, the electronic component 10, the bus bar 42, and the connection component 20 are used as examples of the resistor, but the resistor is not limited to this configuration. Any heat-generating component that generates heat when energized can be selected as the resistor.

[0119] In the above-described embodiment, a configuration has been described in which each weight-reducing portion 88 is a single large opening (through-hole), but the present invention is not limited to this configuration. A single weight-reducing portion 88 may be configured by combining a plurality of small openings formed in a lattice, honeycomb, or slit shape. In this case, the surface area of ​​the metal plate 80 can be secured by the portions of the metal plate 80 that separate the small openings, thereby improving heat dissipation.

[0120] In the above-described embodiment, the wiring board 40 and the busbars 42 are integrally formed, but the present invention is not limited to this configuration. The busbars 42 may be formed separately from the wiring board 40. In the above-described embodiment, a configuration has been described in which the entire weight-reduced portion 88 is disposed at a position offset from the heat-transfer member 92, but the configuration is not limited to this. A part of the weight-reduced portion 88 and the heat-transfer member 92 may overlap when viewed from the Z direction. In the above-described embodiment, a configuration in which the weight-reduced portion 88 is formed in the through-hole has been described, but the present invention is not limited to this configuration. The weight-reduced portion 88 may be a thin-walled portion formed to be thinner than other portions of the flat portion 81. The thin-walled portion may be open on the +Z direction side or the -Z direction side of the flat portion 81. Furthermore, a single metal plate 80 may be formed with a mixture of both through-holes and thin-walled portions.

[0121] In addition, the components in the above-described embodiments can be replaced with well-known components as appropriate, without departing from the spirit of the present invention. [Explanation of symbols]

[0122] 1: Electrical connection unit 10, 10A, 10B, 10C, 10M, 10N, 10X, 10Y, 10Z: Electronic components (resistors, first resistors) 20, 20A, 20B, 20C, 20D, 20E, 20F, 20M, 20N, 30A, 30B: Connecting parts (resistor, first resistor) 40, 40X: First wiring board (board) 40, 40Y: Second wiring board (board) 40, 40Z: Third wiring board (board) 42, 42A, 42B, 42C, 42D, 42E: Busbar (resistor, first resistor) 80: Metal plate (heat dissipation plate) 88, 88A, 88B: Lightweight section 92: Heat transfer material 100: Connecting parts (resistors) SU, SUX, SUY, SUZ: Subunits (circuit components)

Claims

1. a circuit structure having a plurality of resistors and a substrate facing the plurality of resistors; a heat dissipation plate provided so as to overlap the circuit assembly in the thickness direction of the substrate and made of a material having higher thermal conductivity than the substrate; one or more heat transfer members provided between the circuit assembly and the heat dissipation plate, thermally connecting the circuit assembly and the heat dissipation plate; An electrical connection unit in which, at a position of the heat dissipation plate that overlaps the substrate when viewed from the thickness direction but does not overlap with at least a portion of the heat transfer member, the position is formed to be thinner than other portions of the heat dissipation plate, or one or more lightweight portions are formed that penetrate the heat dissipation plate in the thickness direction.

2. the plurality of resistors includes a first resistor, 2. The electrical connection unit according to claim 1, wherein the heat transfer member is disposed at a position overlapping at least a portion of the first resistor when viewed in the thickness direction.

3. 3. The electrical connection unit according to claim 1, wherein the one or more weight-reducing portions include a plurality of weight-reducing portions spaced apart from one another.

4. 3. The electrical connection unit according to claim 1, wherein the area of ​​the one or more weight-reduced portions is larger than the area of ​​the one or more heat transfer members when viewed in the thickness direction.

5. the plurality of resistors includes a first resistor, The first resistor is a bus bar held by the substrate; a connection component that stands upright from the substrate in the thickness direction and is electrically connected to the bus bar; an electronic component supported by the connection component in a state spaced apart from the substrate in the thickness direction and electrically connected to the bus bar via the connection component, 3. The electrical connection unit according to claim 1, wherein the weight-reducing portion is provided at a position overlapping the electronic component when viewed in the thickness direction.

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