Vehicle-mounted power distribution board, electrical junction box, and charging/discharging controller

This application is the U.S. national stage of PCT/JP2016/059839 filed Mar. 28, 2016, which claims priority of Japanese Patent Application No. JP 2015-066281 filed Mar. 27, 2015.

The technology disclosed herein relates to a vehicle-mounted power distribution board, an electrical junction box, and a charging/discharging controller.

As a vehicle-mounted power distribution board that is mounted to a vehicle and has the function of distributing power from a power supply to various vehicle-mounted electric/electronic components, a board is known that includes a circuit structure including a plurality of bus bars and a control circuit board, and electronic components such as a semiconductor element that are mounted to the circuit structure.

Meanwhile, components such as a semiconductor element tend to generate heat and undergo temperature increase during operation. In particular, in the case of such a substrate that allows a large current to flow therethrough, the generated heat may be transferred through a bus bar and a copper foil serving as the conductive materials, as well as a control circuit board to other components that are likely to be influenced by heat, resulting in a failure in the other components.

A technique disclosed herein is directed to a vehicle-mounted power distribution board including: a circuit structure including a control circuit board including a conductive path on at least one of a front surface and a back surface, and a bus bar placed on the control circuit board; and a plurality of electronic components that are mounted to the circuit structure, wherein the plurality of electronic components include a heat generating component that generates heat when current flows through it, and a low heat resistance component that is influenced by heat transferred from the heat generating component, the circuit structure is provided with a bus bar non-arrangement region in which no bus bar is disposed, and the low heat resistance component is disposed in the bus bar non-arrangement region.

Another technique disclosed herein is directed to an electrical junction box including: the vehicle-mounted power distribution board having the above-described configuration; and a case that accommodates the vehicle-mounted power distribution board.

Yet another technique disclosed herein is directed to a charging/discharging controller that is disposed between a vehicle-mounted power supply and a vehicle-mounted electric/electronic component and that controls a voltage of power supplied from the vehicle-mounted power supply and distribution of power to the vehicle-mounted electric/electronic component, including: the vehicle-mounted power distribution board having the above-described configuration and a case that accommodates the vehicle-mounted power distribution board.

With the above-described configuration, it is possible to inhibit transfer of heat from the heat generating component through the bus bars to the low heat resistance component.

As embodiments of the techniques disclosed herein, the following configurations are preferable.

At least part of the bus bar non-arrangement region may serve as a conductive path non-arrangement region in which no conductive path is disposed, and the low heat resistance component may be disposed in the conductive path non-arrangement region. With such a configuration, it is possible to inhibit transfer of heat from the heat generating component through the conductive path to the low heat resistance component.

The control circuit board may include a slit that separates the heat generating component and the low heat resistance component. With such as configuration, it is possible to inhibit transfer of heat from the heat generating component through the control circuit board to the low heat resistance component.

The circuit structure may be disposed in a vertical orientation, the low heat resistance component may be disposed laterally or upward of the heat generating component that is mounted to the circuit structure, and the slit may be disposed so as to separate the heat generating component and the low heat resistance component.

Here, the surrounding air that has been heated by the heat generated from the heat generating component moves upward. Therefore, the low heat resistance component disposed laterally or upward with respect to the heat generating component is more likely to be influenced by heat than the low heat resistance component disposed downward with respect to the heat generating component. Accordingly, by disposing the slit so as to separate the heat generating component and the low heat resistance component that is disposed laterally or upward with respect to the heat generating component, it is possible to more sufficiently inhibit transfer of heat from the heat generating component to the low heat resistance component.

Advantageous Effects of Invention

According to the techniques disclosed herein, it is possible to provide a vehicle-mounted power distribution board, an electrical junction box, and a charging/discharging controller that can inhibit transfer of heat from the heat generating component to the other components that are likely to be influenced by heat.

FIG. 1 is a plan view of a lower case and a vehicle-mounted power distribution board according to an embodiment;

FIG. 2 is a plan view of the vehicle-mounted power distribution board according to an embodiment, in which a region in which a conductive path is disposed is indicated by hatching; and

FIG. 3 is a cross-sectional view of a charging/discharging controller, taken along a position corresponding to the line A-A in FIG. 2 .

An embodiment will be described with reference to FIGS. 1 to 3 . A charging/discharging controller (an example of an electrical junction box) 1 according to the present embodiment is disposed in a vehicle between a power storage device (a vehicle-mounted power supply) such as a battery and various vehicle-mounted electric/electronic components, converts power supplied from the power storage device to have an appropriate voltage, thereafter distributes and supplies the power to each of the electric/electronic components, and controls switching and the like of these supplies of power.

The charging/discharging controller 1 includes a vehicle-mounted power distribution board 10 (hereinafter abbreviated as a “power distribution board 10 ”), and a case 50 that accommodates the power distribution board 10 thereinside. The power distribution board 10 includes a circuit structure 20 and a plurality of electronic components that are mounted to the circuit structure 20 . The case 50 includes a dish-shaped lower case 51 that is overlapped with the circuit structure 20 , and a box-shaped upper case 52 that is assembled to the lower case 51 so as to cover the circuit structure 20 .

The plurality of electronic components include a plurality of semiconductor elements 41 constituted by FETs (Field Effect Transistors), a plurality of capacitors 42 and 43 , and a plurality of ICs (Integrated Circuits) 44 . Some of the plurality of electrolytic capacitors 42 and 43 are high heat resistant electrolytic capacitors 42 having a relatively high heat resistance, and the rest are low heat resistant electrolytic capacitors 43 having a lower heat resistance than the high heat resistant electrolytic capacitors 42 . The semiconductor elements 41 are an example of a heat generating component that generates heat when current flows through it. The low heat resistant electrolytic capacitors 43 and the ICs 44 are an example of a low heat resistance component that is likely to be influenced by heat transferred from the heat generating component. Note that in the following description, a subscript is attached to the reference numeral when one semiconductor element 41 is described so as to be distinguished from the others, and no subscript is attached to the reference numeral when the semiconductor elements 41 are collectively referred to without distinction. The same applies to the other electronic components.

The circuit structure 20 includes a control circuit board 21 and a plurality of bus bars 31 .

The control circuit board 21 is a printed circuit board having a commonly used configuration in which a conductive path 23 is formed by a printed wiring technique on a front surface and a back surface of a thin insulating plate 22 made of an insulating material such as a glass base material or a glass non-woven fabric base material. One (the bottom surface in FIG. 3 ) of the front and back surfaces of the control circuit board 21 constitutes a bus bar arrangement surface 21 A on which the bus bars 31 are disposed, and the other surface (the upper surface in FIG. 3 ) is a mounting surface 21 B on which the electronic components are disposed. Note that in view of ease of viewing the drawings, the conductive path 23 has been omitted in FIGS. 1 and 2 . FIG. 3 shows the conductive path 23 disposed on the mounting surface 21 B has been omitted, and only the conductive path 23 disposed on the bus bar arrangement surface 21 A.

The control circuit board 21 includes a plurality of component insertion holes 24 A and 24 B for disposing electronic components. The component insertion holes 24 A and 24 B are holes extending through the control circuit board 21 from the bus bar arrangement surface 21 A to the mounting surface 21 B. The component insertion holes 24 A, which constitute part of these holes, are holes for disposing the semiconductor elements 41 , and are sized such that one semiconductor element 41 can be disposed inside one component insertion hole 24 A. The other component insertion holes 24 B are holes for disposing the high heat resistant electrolytic capacitor 42 , and are sized such that three high heat resistant electrolytic capacitors 42 can be arranged inside one component insertion hole 24 B.

Each of the plurality of bus bars 31 is a plate-shaped member formed of a metal having excellent conductivity. The plurality of bus bars 31 are disposed on the same plane and are spaced apart from each other. The bus bars 31 are bonded to the bus bar arrangement surface 21 A of the control circuit board 21 by using a bonding member (e.g., adhesive tape, an adhesive sheet, an adhesive agent, or the like).

In a state in which the circuit structure 20 is attached to a vehicle, the circuit structure 20 is disposed in a vertical orientation, or in other words, an orientation (the orientation shown in FIG. 3 ) in which the plate surface direction of the control circuit board 21 coincides with a vertical direction.

Part of a region of the control circuit board 21 serves as bus bar non-arrangement regions 25 A, 25 B, and 25 C in which no bus bar 31 is disposed.

A low heat resistant electrolytic capacitor 43 A and an IC 44 A, and 44 B which are low heat resistance components, are disposed in one of the plurality of bus bar non-arrangement regions 25 A, 25 B, and 25 C, namely, the bus bar non-arrangement region 25 A (the bus bar non-arrangement region located on the upper right in FIG. 1 ). The low heat resistant electrolytic capacitor 43 A and the IC 44 A and 44 B are disposed on the mounting surface 21 B of the control circuit board 21 . Although not shown in detail, the low heat resistant electrolytic capacitor 43 A and the IC 44 A, and 44 B each have a plurality of terminals, and the terminals are connected to the conductive path 23 disposed on the mounting surface 21 B.

Part of one bus bar non-arrangement region 25 A serves as a conductive path non-arrangement region 26 A. The conductive path non-arrangement region 26 A is a region in which no conductive path 23 is disposed on the bus bar arrangement surface 21 A of the control circuit board 21 . In FIG. 2 , the region in which the conductive path 23 is disposed on the bus bar arrangement surface 21 A is indicated by hatching, and the unhatched region of the bus bar non-arrangement region 25 A is the conductive path non-arrangement region 26 A. The low heat resistant electrolytic capacitors 43 A and the IC 44 A, and 44 B are disposed in the conductive path non-arrangement region 26 A.

One or both of the low heat resistant electrolytic capacitor 43 and the IC 44 are also disposed in the other bus bar non-arrangement regions 25 B and 25 C (the bus bar non-arrangement regions located on the lower side of the bus bar non-arrangement region 25 A and the lower left of the control circuit board 21 in FIG. 1 ). Note that as shown in FIG. 2 , the entirety of the other bus bar non-arrangement regions 25 B and 25 C serves as the conductive path non-arrangement region.

On the other hand, the semiconductor element 41 , which is a heat generating component, and the high heat resistant electrolytic capacitor 42 , which is a component having a relatively high heat resistance, are disposed on the control circuit board 21 in a region in which the bus bar 31 is disposed. The semiconductor element 41 is disposed inside the corresponding component insertion hole 24 A. Although not shown in detail, the semiconductor elements 41 each include a plurality of terminals. At least one of the terminals (ground terminal) is connected to the conductive path 23 disposed on the mounting surface 21 B, and the other terminals (a drain terminal and a gate terminal) are connected to the bus bars 31 . The high heat resistant electrolytic capacitor 42 is disposed inside the corresponding component insertion hole 24 B. Although not shown in detail, the high heat resistant electrolytic capacitors 42 have a plurality of terminals, and the terminals are connected to the bus bars 31 .

Slits 27 A, 27 B, and 27 C are disposed in the bus bar non-arrangement regions 25 A, 25 B, and 25 C, respectively. The slit 27 A disposed in the bus bar non-arrangement region 25 A extends along the outer peripheral edge of the bus bar non-arrangement region 25 A (i.e., along a lateral edge of the bus bar 31 adjacent to the bus bar non-arrangement region 25 A). The slit 27 A is disposed between the low heat resistant electrolytic capacitor 43 A and the IC 44 A, 44 B and the semiconductor element 41 A adjacent thereto, and separates the low heat resistant electrolytic capacitor 43 A and the IC 44 A, and 44 B from the semiconductor element 41 A.

The slit 27 A has a zigzag shape formed by a combination of a plurality of linear portions 27 A 1 , 27 A 2 , and 27 A 3 , one linear portion 27 A 1 is disposed between one semiconductor element 41 A and one low heat resistant electrolytic capacitor 43 disposed laterally with respect to the semiconductor element 41 A, and extends in a vertical direction. Another linear portion 27 A 2 is disposed between one semiconductor element 41 A and one IC 44 B disposed upward with respect to the semiconductor element 41 A, and extends in a horizontal direction. In this manner, the slit 27 A separates one semiconductor element 41 A and the low heat resistance component (the low heat resistant electrolytic capacitor 43 A and the IC 44 A or 44 B) disposed laterally or upward with respect to the semiconductor element 41 A.

Likewise, the slits 27 B and 27 C are disposed in the other bus bar non-arrangement regions 25 B and 25 C, and the slits 27 B and 27 C separate the low heat resistant electrolytic capacitor 43 or the IC 44 and the semiconductor element 41 . Note that the slits 27 B and 27 C of the other bus bar non-arrangement regions 25 B and 25 C are each formed as one straight line.

As described above, according to the present embodiment, the control circuit board 21 includes the bus bar non-arrangement regions 25 A, 25 B, and 25 C in which no bus bar 31 is disposed, and the low heat resistant electrolytic capacitor 43 and the IC 44 are disposed in the bus bar non-arrangement regions 25 A, 25 B, and 25 C. With such a configuration, it is possible to inhibit the heat generated from the semiconductor element 41 , which is a heat generating component, from being transferred through the bus bars 31 to the low heat resistant electrolytic capacitor 43 or the IC 44 , which are low heat resistance components.

Part of the bus bar non-arrangement region 25 A serves as the conductive path non-arrangement region 26 A in which no conductive path 23 is disposed on the bus bar arrangement surface 21 A, and the low heat resistant electrolytic capacitor 43 A and the IC 44 A, and 44 B are disposed in the conductive path non-arrangement region 26 A. Furthermore, the entirety of the bus bar non-arrangement regions 25 A and 25 B serves as the conductive path non-arrangement region, and one or both of the low heat resistant electrolytic capacitor 43 and the IC 44 are disposed in these regions. With such a configuration, it is possible to inhibit the heat generated from the semiconductor element 41 from being transferred through the conductive path 23 to the low heat resistant electrolytic capacitor 43 or the IC 44 .

Furthermore, the control circuit board 21 includes the slits 27 A, 27 B, and 27 C disposed so as to separate the semiconductor element 41 and the low heat resistant electrolytic capacitor 43 or the IC 44 . With such a configuration, it is possible to inhibit the heat generated from the semiconductor element 41 from being transferred through the control circuit board 21 to the low heat resistant electrolytic capacitor 43 or the IC 44 .

In addition, the circuit structure 20 is disposed in a vertical orientation in which the plate surface direction of the control circuit board 21 coincides with a vertical direction, and the slits 27 A, 27 B, and 27 C are disposed so as to separate the semiconductor element 41 and the low heat resistant electrolytic capacitor 43 or the IC 44 disposed laterally or upward with respect to the semiconductor element 41 .

Here, the surrounding air that has been heated by the heat generated from the semiconductor element 41 moves upward. Therefore, the components disposed laterally or upward with respect to the semiconductor element 41 are more likely to be influenced by heat than the components disposed downward with respect to the semiconductor element 41 . Thus, by disposing the slits 27 A, 27 B, and 27 C so as to separate the semiconductor element 41 and the low heat resistant electrolytic capacitor 43 or the IC 44 disposed laterally or upward with respect to the semiconductor element 41 , it is possible to effectively inhibit transfer of heat from the semiconductor element 41 to the low heat resistant electrolytic capacitor 43 or the IC 44 .

In particular, a large current flows through the charging/discharging controller 1 that is disposed between a vehicle-mounted power supply and a vehicle-mounted electric/electronic component, and controls the voltage of the power supplied from the vehicle-mounted power supply and the distribution of the power to the vehicle-mounted electric/electronic component. Therefore, handling the problem of heat generated from the heat generating component such as the semiconductor element 41 is an important issue. The power distribution board 10 having the above-described configuration can be preferably applied to such a charging/discharging controller 1 .

Other Embodiments

The technology disclosed herein is not limited to the embodiment described above by way of the description and the drawings, and includes, for example, various embodiments as follows.

(1) Although the above embodiment illustrates the semiconductor element 41 , the capacitors 42 and 43 , and the IC 44 as an example of the electronic component, other electronic components may also be mounted to the circuit structure as needed.

(2) The shape and the size of the component insertion holes 24 A and 24 B are not limited to those described in the above embodiment, and may be any shape and any size corresponding to the shape and the size of the bottom surface of electronic components disposed thereinside, and the number of such electronic components.

(3) Although the circuit structure 20 includes the three bus bar non-arrangement regions 25 A, 25 B, and 25 C in the above embodiment, the number, the outside shape, the arrangement positions, and the like of the bus bar non-arrangement regions are not limited to those described in the embodiment, and may be set in accordance with the type, the number, and the like of the electronic components disposed therein. Likewise, the number, the shape, the arrangement, and the like of the conductive path non-arrangement regions and the slits are not limited to those described in the embodiment, and may be set in accordance with the types, the number, and the like of the electronic components disposed therein.

(4) Although the conductive path non-arrangement region 26 A is a region in which no conductive path 23 is disposed on the bus bar arrangement surface 21 A of the control circuit board 21 in the above embodiment, the conductive path non-arrangement region may be a region in which no conductive path is disposed on the mounting surface of the control circuit board, or may be a region in which no conductive path is disposed on both the mounting surface and the bus bar arrangement surface.

(5) Although one slit 27 A has a zigzag shape and the other slits 27 B and 27 C have the shape of a straight line in the above embodiment, the shapes of the slits are not limited to those described in the present embodiment, and may be a U-shape or C-shape, for example.