WO2022249939A1

WO2022249939A1 - Electric apparatus

Info

Publication number: WO2022249939A1
Application number: PCT/JP2022/020624
Authority: WO
Inventors: 隆弘須永; 秀幸久保木
Original assignee: 株式会社オートネットワーク技術研究所; 住友電装株式会社; 住友電気工業株式会社
Priority date: 2021-05-24
Filing date: 2022-05-18
Publication date: 2022-12-01
Also published as: JP2022179901A

Abstract

An electric apparatus 1 comprises: a housing 10 with a sealed space CS therein; a liquid refrigerant 20L stored in the housing 10; and at least one heat-generating component 30 which is immersed in the liquid refrigerant 20L and generates heat when energized. Over the liquid refrigerant 20L in the housing 10, a gas-phase space GS is formed into which a vaporized refrigerant 20G obtained by vaporization of the liquid refrigerant 20L due to the heat generated by the heat-generating component 30 is released. A cooling wall portion 15A of the housing 10 adjoining the gas-phase space GS is provided with a heat-exchange mechanism 50 for absorbing heat from the inside of the housing 10 and then releasing the heat to the outside of the housing 10. A vertically extending guide member 40 is provided between a side wall 17 of the housing continuous from the cooling wall portion 15A and the heat-generating component 30. In the sealed space CS, a communication path P1 is formed over the guide member 40 along which at least the vaporized refrigerant 20G can circulate, and a flow path P2 is formed under the guide member 40 along which the liquid refrigerant 20L can circulate.

Description

electrical equipment

This disclosure relates to electrical equipment.

Conventionally, as an example of electric equipment, a power conversion device that converts an input DC voltage into a DC voltage of a predetermined level and outputs the DC voltage is known. A power conversion device is mounted in a vehicle such as an electric vehicle or a hybrid vehicle, for example. 2. Description of the Related Art Electronic components used in electrical equipment such as power converters are heat-generating components that generate heat when energized, and generate a relatively large amount of heat. If the heat-generating parts are not well cooled, the temperature of the entire electrical equipment may increase and the performance may deteriorate.

As a means for cooling heat-generating components, Patent Document 1 below, for example, discloses an ebullient cooling device. In this boiling cooling device, a heat-generating component is attached to a heat-receiving wall of a cooling vessel that stores a liquid refrigerant, and heat is received from the heat-generating component to boil the liquid refrigerant. The cooling container is formed with a refrigerant storage portion and a refrigerant condensing portion, and a heat exchange body having a heat absorbing portion and a heat radiating portion is inserted into the opening portion of the cooling container. The heat sink is located inside the refrigerant condensing section of the cooling vessel, and the boiling liquid refrigerant conducts heat to the heat sink to condense. The heat transferred to the heat absorbing portion is radiated from the heat radiating portion via the heat exchange body. In this way, the heat-generating components are efficiently cooled by heat exchange while boiling the liquid refrigerant.

JP 2012-167866 A

In the above ebullient cooling device, the heat of the heat-generating parts is transferred to the liquid refrigerant through the heat-receiving wall. Here, if the heat-generating parts can be immersed in a liquid coolant to perform boiling cooling, a further improvement in cooling efficiency can be expected. In order to realize such cooling, the liquid refrigerant boils (heat is received from the heat-generating parts), the vaporized refrigerant condenses (heat is transferred to the heat exchange member), and the condensed liquid It is important to regulate the flow of the refrigerant so that the circulation of the refrigerant, including the circulation of the refrigerant, is performed smoothly.

The technology disclosed in the present specification has been perfected based on the circumstances described above, and aims to provide an electrical device capable of efficiently cooling heat-generating components by utilizing the boiling phenomenon of a liquid coolant. With the goal.

An electrical device according to the present disclosure includes a housing whose interior is a sealed space, a liquid coolant stored inside the housing, and at least one heat-generating component that is immersed in the liquid coolant and generates heat when energized. and a vapor phase space is formed above the liquid refrigerant in the housing, and is in contact with the vapor phase space. The cooling wall portion of the housing is provided with a heat exchange mechanism that absorbs heat from the inside of the housing and radiates heat to the outside of the housing. A guide member extending in the vertical direction is provided between the heat-generating component, and a communication path through which at least the vaporized refrigerant can flow is formed above the guide member in the interior of the sealed space, Below the guide member, a channel is formed through which the liquid coolant can flow.

According to the present disclosure, it is possible to provide an electrical device capable of efficiently cooling heat-generating components.

FIG. 1 is a perspective view schematically showing the configuration inside a housing of an electrical device according to an embodiment. FIG. 2 is a side view schematically showing the internal configuration of the housing of the electrical equipment. FIG. 3 is an explanatory diagram showing a process of evacuating the inside of the housing of the electrical equipment. FIG. 4 is an explanatory diagram showing a process of injecting the liquid coolant into the housing of the electrical equipment. FIG. 5A is an explanatory diagram showing a state in which a valve of a pipe connected to the inside of the housing is closed in the step of forming a sealed space inside the housing of the electrical equipment. FIG. 5B is an explanatory view showing how the pipe is crimped and closed at a position closer to the housing than the valve closed in FIG. 5A in the process of forming a sealed space inside the housing of the electrical device. FIG. 5C is an explanatory view showing how the pipe is cut at a position outside the crimped portion in FIG. 5B in the step of forming a sealed space inside the housing of the electrical device.

[Description of Embodiments of the Present Disclosure]
First, embodiments of the present disclosure are enumerated and described.

(1) An electrical device according to the present disclosure includes a housing having a closed space inside, a liquid refrigerant stored inside the housing, and at least one element that is immersed in the liquid refrigerant and generates heat when energized. and a heat-generating component, wherein a gas phase space is formed above the liquid coolant inside the housing, in which vaporized coolant obtained by vaporizing the liquid coolant due to heat generated by the heat-generating component is discharged, and the gas phase is A cooling wall portion of the housing that is in contact with the space is provided with a heat exchange mechanism that absorbs heat from the inside of the housing and dissipates heat to the outside of the housing. and the heat-generating component, a guide member extending in the vertical direction is provided, and a communication passage through which at least the vaporized refrigerant can flow is formed above the guide member in the sealed space. A channel through which the liquid coolant can flow is formed below the guide member.

According to the configuration (1) above, the guide member separates and forms the refrigerant boiling portion, the refrigerant condensing portion, and the refrigerant recirculating portion in the sealed space inside the housing. That is, the upward gas-liquid two-phase flow containing the liquid refrigerant and the vaporized refrigerant in the central portion of the housing and the liquid-phase flow in which the liquid refrigerant descends in the vicinity of the side wall are separated by the guide member, and the refrigerant flows inside the housing. circulates smoothly. Via the coolant circulating in this way, the heat from the heat-generating component is transmitted to the heat exchange mechanism, and is smoothly radiated to the outside of the housing. As a result, the heat-generating components can be efficiently cooled in the electric device having the above configuration.

(2) The electrical device according to the present disclosure further includes a circuit board arranged inside the housing, and the heat-generating component is positioned on at least one board surface of two board surfaces of the circuit board. It is preferable that the circuit board is mounted on the upper surface of the board, and that the circuit board is disposed in a posture in which the normal line of the board surface is horizontal.
According to the configuration (2) above, in addition to the guide member extending in the vertical direction, the circuit board arranged in the housing in an upright posture with the substrate surface extending in the vertical direction also regulates the flow of the coolant. It functions as a current plate. As a result, the coolant circulates more smoothly inside the housing, and the heat-generating parts are efficiently cooled.

(3) The electrical device according to the present disclosure further includes a bus bar that is elongated in one direction, and the bus bar is mounted on the circuit board in such a manner that the longitudinal direction of the bus bar is the vertical direction. preferably.
According to the configuration (3) above, the bus bar also functions as a rectifying plate that regulates the flow of the refrigerant. As a result, the coolant flows more smoothly, and the heat-generating parts are cooled more efficiently.

(4) the heat-generating component has a flat lower outer plane located on the lower side of the outer surface of the heat-generating component, and the lower outer plane is inclined when viewed from the normal direction of the substrate surface; It is preferably mounted on the substrate surface.
According to the configuration (4) above, even when the plane forming the outer surface of the heat-generating component is positioned below the heat-generating component, that is, even when the heat-generating component has a lower outer plane, Since the lower outer plane is arranged in an inclined manner, the vaporized refrigerant rises around the heat-generating component along the inclination of the lower outer plane. As a result, it is possible to reduce the occurrence of a situation in which the vaporized refrigerant stays and the cooling of the heat-generating parts is hindered.

(5) It is preferable that the electric device according to the present disclosure includes a plurality of the heat-generating components, and the heat-generating components are mounted on both the one substrate surface and the other substrate surface.
According to the configuration (5) above, it is possible to improve the mounting density of the heat-generating components on the circuit board and reduce the size of the electric device.

(6) Preferably, the upper end of the guide member is inclined upward in a direction away from the side wall.
According to the configuration (6) above, the liquid that is condensed in the refrigerant condensing section and drips without obstructing the flow of the vaporized refrigerant from the refrigerant boiling section to the refrigerant condensing section, that is, from above the heat-generating component toward the vicinity of the cooling wall section. The coolant can be received in a wide range by the upper end portion of the guide member and guided to the coolant circulation portion near the side wall.

(7) It is preferable that the housing has an inclined wall connecting the side wall and the upper wall while being inclined, and the cooling wall portion is provided on the inclined wall.
According to the above configuration (7), most of the liquid refrigerant generated by condensation of the vaporized refrigerant in contact with the cooling wall portion is guided to the refrigerant return flow portion along the inclined wall and the side wall.

(8) Preferably, the gas phase space is evacuated.
Here, "vacuum" refers to a state in a space filled with gas having a pressure lower than normal atmospheric pressure, as defined in Japanese Industrial Standards. According to the configuration (8) above, the boiling point of the liquid refrigerant can be lowered below that under normal pressure, and the boiling efficiency of the liquid refrigerant and thus the cooling efficiency of the heat-generating parts can be improved.

[Details of the embodiment of the present disclosure]
Embodiments of the present disclosure are described below. The present invention is not limited to these examples, but is indicated by the scope of the claims, and is intended to include all modifications within the meaning and scope of equivalents of the scope of the claims.

<Embodiment>
Embodiments of the present disclosure are described with reference to FIGS. 1-5C. In the following description, the upper side in FIG. 2 is defined as the top, the left side in FIG. 2 is defined as the front, and the back side of the paper surface in FIG. In addition, regarding a plurality of identical members, only some members may be given reference numerals, and the reference numerals of other members may be omitted.

(Electrical equipment 1)
In this embodiment, an electric device 1 mounted in a vehicle such as an automobile will be exemplified. The electrical device 1 is not particularly limited, but for example is a device including a switching type DC-DC converter (DC voltage converter) that converts an input DC voltage into a DC voltage of a predetermined level and outputs it, It has a well-known circuit configuration. The electric device 1 includes, for example, a first converter that converts a DC voltage to an AC voltage, a transformer that transforms the AC voltage, and a second converter that converts the AC voltage to a DC voltage. It is composed of a rectifying circuit for conditioning, a resonant circuit, a smoothing circuit, and the like.

As shown in FIGS. 1 and 2, the electrical device 1 according to this embodiment includes a housing 10 and a circuit board 60 arranged inside the housing 10. As shown in FIGS. The circuit board 60 is attached with the heat-generating components 30 such as the electronic components constituting the circuit described above. The electric device 1 is mounted on the vehicle in such a posture that the normal line of the board surface 61 of the circuit board 60 is horizontal as shown in FIG. Note that the term “horizontal” includes the case where the normal line of the board surface 61 of the circuit board 60 is horizontal, and also includes the case where it can be recognized as being substantially horizontal even if it is not horizontal.

(Case 10)
As shown in FIGS. 1 and 2, the housing 10 according to the present embodiment has a rectangular parallelepiped deep box shape as a whole. More specifically, a front wall 19F, a rear wall 19B, a left wall 17L, and a right wall 17R rising from the peripheral edge of the rectangular lower wall 11; and two sloping walls 15 located between the wall 17R and the top wall 13. The inclined walls 15 extend downward from the left and right edges of the upper wall 13 while being inclined in directions away from each other, and are connected to the upper edges of the left side wall 17L or the right side wall 17R. Hereinafter, the left side wall 17L and the right side wall 17R may be collectively referred to as the side wall 17. As shown in FIG. The upper wall 13 has a rectangular shape slightly smaller than the lower wall 11 . The upper wall 13 has the same dimension in the front-rear direction as the lower wall 11, but has smaller dimensions in the lateral direction than the lower wall 11, and the center of the upper wall 13 overlaps the center of the lower wall 11 when viewed from above. In other words, the side wall 17 and the inclined wall 15 form a rectangular shape, and the front wall 19F and the rear wall 19B form a planar shape in which the base of an isosceles trapezoid overlaps the upper side of the rectangle.
The housing 10 forms a sealed space CS in its interior, and basically liquid and gas are not allowed to flow between the inside and outside of the housing 10 .

A total of eight walls that make up the housing 10 can be made of materials containing metals such as aluminum and stainless steel. Among metals, it is preferable to use a material containing a metal with high thermal conductivity such as aluminum or an aluminum alloy, and a stainless steel surface plated with copper or nickel may be used. In the present embodiment, since a part of the inclined wall 15 functions as a cooling wall portion 15A, as will be described later, from the viewpoint of improving the heat exchange efficiency of the heat exchange mechanism 50 and thus the cooling efficiency of the heat generating component 30, the inclined wall 15 It is preferable to use a plate material of a copper alloy for the slanted wall 15 or to plate a part or the whole of the slanted wall 15 with copper.

(Heat exchange mechanism 50)
As shown in FIGS. 1 and 2, the inclined wall 15 of the housing 10 is provided with a heat exchange mechanism 50 . The heat exchange mechanism 50 is not particularly limited as long as it can absorb heat from the inside of the housing 10 and dissipate the heat to the outside of the housing 10 . In this embodiment, a heat exchange structure is exemplified by attaching a box body in which cooling pipes 51 for circulating cooling water or the like are arranged to the outer surface of the inclined wall 15 formed of a metal with high thermal conductivity. ing. A portion of the inclined wall 15 to which the box is attached serves as a cooling wall portion 15A. In addition to such a structure, heat radiation fins may be attached to the outside of the inclined wall 15 so as to function as a heat sink. In the heat exchange mechanism 50 according to the present embodiment, the heat inside the housing 10 is transmitted to the cooling water or the like in the cooling pipe 51 through the cooling wall portion 15A of the inclined wall 15, and the cooling water or the like circulates to The heat is radiated to the outside of the housing 10 . As a result, the temperature of the cooling wall portion 15A and the vicinity thereof is maintained at a lower temperature than the vicinity of the other walls.

(Refrigerant 20)
A coolant 20 is injected inside the housing 10 . Hereinafter, of the coolant 20, the liquid coolant is referred to as the liquid coolant 20L, and the gaseous coolant is referred to as the vaporized coolant 20G. As the refrigerant 20, for example, one or more selected from the group consisting of perfluorocarbons, hydrofluoroethers, hydrofluoroketones, fluorine-based inert liquids, water, and alcohols such as methanol and ethanol can be used. From the viewpoint of miniaturizing the electric device 1 by reducing the distance between the heat generating components 30, the refrigerant 20 is insulating, has a low content of dust particles per unit volume, and has a large insulating property. It is preferable to have pressure resistance. Moreover, from the viewpoint of improving the cooling efficiency, the refrigerant 20 preferably has a relatively low boiling point.

As shown in FIGS. 1 and 2, a gas phase space GS is formed above the liquid coolant 20L stored in the housing 10. As shown in FIGS. That is, the inside of the housing 10 is filled with the refrigerant 20 as the liquid refrigerant 20L in an amount that does not completely fill the sealed space CS. The vaporized refrigerant 20G generated by the liquid refrigerant 20L receiving heat from the heat generating component 30 rises in the liquid refrigerant 20L and is released into the gas phase space GS. The cooling wall portion 15A of the inclined wall 15 is provided at a position above the liquid surface of the liquid refrigerant 20L stored in the housing 10 and in contact with the gas phase space GS. In this embodiment, the liquid coolant 20L is stored in the housing 10 so that the entire circuit board 60 is immersed in the liquid coolant 20L. However, the entire circuit board 60 is always immersed in the liquid coolant 20L. is not required. When a plurality of heat-generating components 30 are arranged inside the housing 10, some of the heat-generating components 30 may be immersed in the liquid coolant 20L. It is preferable that the elements and coils are immersed, and it is more preferable that all the heat-generating components 30 are always immersed in the liquid coolant 20L. This is because the heat generating component 30 can be directly cooled by the liquid coolant 20L by immersing the heat generating component 30 in the liquid coolant 20L.

(circuit board 60)
As shown in FIGS. 1 and 2, a rectangular flat circuit board 60 is accommodated inside the housing 10 . The circuit board 60 is a plate-shaped member having a well-known configuration, in which conductive paths are formed on the mounting surface of an insulating plate made of an insulating material, for example, by printed wiring technology. The conductive paths are made of a material containing metal such as copper. In the electric device 1, the circuit board 60 is arranged inside the housing 10 in such a posture that the normal lines of the two board surfaces 61, which are the plate surfaces of the circuit board 60, are horizontal. In other words, the circuit board 60 is accommodated inside the housing 10 in a so-called upright posture in which the board surface 61 extends in the vertical direction.

As shown in FIG. 1, in this embodiment, the left edge, right edge, and upper edge of the circuit board 60 housed inside the housing 10, the left side wall 17L, the right side wall 17R, and the upper wall of the housing 10 13 are formed with gaps through which the liquid refrigerant 20L can flow. Further, as shown in FIG. 2, in the present embodiment, of the two board surfaces 61 of the circuit board 60, one board surface 61A located on the front side and the other board surface 61B located on the rear side are both surfaces. Heat-generating components 30 are mounted on both

substrate surfaces

61A and 61B of the circuit board 60, which serve as mounting surfaces. Further, as shown in FIGS. 1 and 2, a bus bar 70, which will be described later, is arranged to extend vertically at the central position in the left-right direction of both

substrate surfaces

61A and 61B. In this embodiment, the arrangement of the heat-generating components 30 mounted on one substrate surface 61A is different from the arrangement of the heat-generating components 30 mounted on the other substrate surface 61B.

(Heat-generating component 30)
As shown in FIGS. 1 and 2, various heat-generating components 30 are mounted on the board surface 61 of the circuit board 60 . The heat-generating component 30 is mounted on the board surface 61, which is the mounting surface of the circuit board 60, in a known manner by a known technique such as soldering. electrically connected. Between the heat-generating components 30 mounted on the substrate surface 61 and between the heat-generating components 30 and the inner surface of each wall of the housing 10, gaps are formed through which the liquid coolant 20L can flow. The heat-generating components 30 include, for example, resistors, coils, capacitors, fuses, relays, diodes, ICs (Integrated Circuits), and switching elements such as FETs (Field Effect Transistors). 1 and 2 show, as the heat-generating component 30, an FET 30A, which is a switching element, a coil 30B, and a resistor 30C.

The heat-generating component 30 is arranged on the lower side inside the housing 10 . As shown in FIGS. 1 and 2, the circuit board 60 according to the present embodiment has a plurality of heat generating components 30 on both

board surfaces

61A and 61B, and the plurality of heat generating components 30 are generally It is mounted at a lower position on the substrate surface 61 . By arranging the heat-generating component 30 on the lower side in the housing 10, convection of the coolant 20 is likely to occur, thereby improving heat dispersion. In particular, the FET 30A generates a particularly large amount of heat when energized among the various heat-generating components 30 included in the electric device 1, which is a DC-DC converter, and is relatively small. can be effectively cooled. In this embodiment, a three-terminal type FET 30A having a rectangular parallelepiped shallow box-shaped main body in which an element is built and three terminals projecting from the main body, and a coil 30B built in a rectangular parallelepiped shallow box-shaped outer box is used, but the FET 30A and the coil 30B are not limited to such shapes.

As shown in FIG. 1, in this embodiment, the four FETs 30A mounted on the substrate surface 61A on the left side of a bus bar 70, which will be described later, are arranged at positions that do not overlap each other in the horizontal direction. In this embodiment, these four FETs 30A are arranged at positions that do not overlap each other even in the vertical direction. By arranging the FETs 30A in this manner, it is possible to secure a large interval between the FETs 30A, which is preferable from the viewpoint of cooling efficiency. The four FETs 30A mounted on the right side of the bus bar 70 on the substrate surface 61A and the coil 30B mounted above the FETs 30A have a main body portion and an outer box formed in the shape of a shallow rectangular parallelepiped, which are mounted on the substrate surface 61A. It is mounted in an inclined posture when viewed from the front, which is the normal direction of the More specifically, for example, the coil 30B has two flat lower outer planes 31 positioned below the coil 30B on the outer surface, as shown in FIG. , and the other lower outer plane 31B faces to the lower right.

(Busbar 70)
As shown in FIGS. 1 and 2, bus bars 70 are arranged on both

substrate surfaces

61A and 61B of the circuit board 60. As shown in FIGS. The bus bar 70 is a conductive member formed into a longitudinal flat plate shape elongated in one direction by pressing or forming a metal plate material. The bus bar 70 can be made of, for example, a material containing copper with high thermal conductivity. As shown in FIGS. 1 and 2, the bus bar 70 is arranged on the substrate surface 61 so that its longitudinal direction is aligned with the vertical direction and the plate surface is perpendicular to the substrate surface 61. is electrically connected to a conductive path formed in the As shown in FIG. 2, between the front edge of the busbar 70 mounted on one substrate surface 61A and the inner surface of the front wall 19F of the housing 10, the busbar mounted on the other substrate surface 61B Between the rear edge of 70 and the inner surface of the rear wall 19B, and between the lower edge and the inner surface of the lower wall 11, gaps are formed through which the liquid refrigerant 20L and the vaporized refrigerant 20G can flow.

As shown in FIG. 1, in this embodiment, the bus bar 70 is arranged at the center position in the horizontal direction on both

substrate surfaces

61A and 61B. Four FETs 30A are mounted on the left side of 70, and a coil 30B, a resistor 30C, and four FETs 30A are mounted on the right side of busbar 70. FIG. Thereby, a plurality of heat-generating components 30 that generate a particularly large amount of heat are arranged on the substrate surface 61</b>A in a separated state on the left and right sides of the bus bar 70 . The bus bar 70 is also electrically connected to the conductive path formed on the substrate surface 61 in the same manner as the heat generating component 30 . That is, the heat-generating component 30 and the bus bar 70 mounted on both

substrate surfaces

61A and 61B are connected to each other through conductive paths formed containing metal.

(Guide member 40)
A guide member 40 extending vertically as a whole is provided between the side wall 17 of the housing 10 and the heat-generating component 30 . The guide member 40 can be formed of, for example, a resin plate or a metal plate made of resin having high heat resistance such as polycarbonate. The guide member 40 is basically formed so that the liquid refrigerant 20L and the vaporized refrigerant 20G are difficult to permeate. As shown in FIGS. 1 and 2 , the guide members 40 are arranged along the left and right side edges of the board surface 61 of the circuit board 60 . As a result, the mounting area of the heat-generating component 30 on the substrate surface 61 can be secured as large as possible. For example, as shown in FIG. 1, the heat-generating component 30 mounted on the substrate surface 61 is sandwiched between the left guide member 40 and the right guide member 40 . A bus bar 70 extends vertically in the center of the pair of left and

right guide members

40 , 40 .

As shown in FIGS. 1 and 2, in the sealed space CS formed in the housing 10, above the guide member 40, between the upper wall 13 and the upper end of the guide member 40, at least vaporized refrigerant is provided. A communication path P1 through which 20G can flow is formed. In the present embodiment, the upper end of the guide member 40 arranged along the side edge of the circuit board 60 is positioned below the liquid surface of the liquid coolant 20L, and the upper end of the guide member 40 in the communication path P1. and the liquid surface of the liquid refrigerant 20L, the liquid refrigerant 20L and the vaporized refrigerant 20G can flow. The vaporized coolant 20G flows through the gas phase space GS between the upper wall 13 of the communication path P1 and the liquid surface of the liquid coolant 20L.

Further, as shown in FIGS. 1 and 2, in the closed space CS formed in the housing 10, below the guide member 40, liquid is trapped between the lower wall 11 and the lower end of the guide member 40. A flow path P2 is formed through which the coolant 20L can flow. In the present embodiment, the lower end of the guide member 40 arranged along the side edge of the circuit board 60 is positioned above the lower end of the circuit board 60, and the lower end of the guide member 40 is aligned with the lower wall 11. They are arranged with a gap between them. The liquid refrigerant 20L and the vaporized refrigerant 20G can flow through this gap that constitutes the flow path P2.

The upper end portion 40T of the guide member 40 located above the heat-generating component 30 is inclined upwardly away from the side wall, in other words, toward the center of the substrate surface 61 in the left-right direction toward the heat-generating component 30 side. It is A gap is formed between the upper ends of the pair of

guide members

40 and 40 and between the upper end of each guide member 40 and the bus bar 70, so that the liquid coolant 20L and the vaporized coolant 20G are more likely to flow than the upper end of the guide member 40. It can move upward.

(Method for Manufacturing Electric Device 1 (Formation of Vacuum Sealed Space CS and Injection of Coolant 20))
Next, an example of a method for manufacturing the electric device 1 according to this embodiment will be described with reference to FIGS. 3 to 5C. The heat-generating component 30 and the bus bar 70 manufactured by a known method are mounted on the board surface 61 of the circuit board 60 by a known method as described above. Further, the guide member 40 is provided on the substrate surface 61 as described above. The circuit board 60 on which the heat-generating component 30, the bus bar 70, and the guide member 40 are arranged is arranged in the above-described posture inside the housing 10 that forms the closed space CS. In manufacturing the electric device 1, as shown in FIG. 3 and the like, a pipe 101 is connected to the housing 10 to connect the inside and outside of the housing 10 so that the air and the liquid refrigerant 20L can flow.

As shown in FIGS. 3 and 4, the pipe 101 is provided with a plurality of valves V1 to V7, an intake pipe 101A connected to a cold trap (CT) 103 and a vacuum pump (P) 104, and a liquid and a liquid supply pipe 101B connected to a liquid storage tank 105 in which 20L of refrigerant is stored. When the valves V1 to V3 located on the housing 10 side of the branch point are opened, and the valve V4 provided in the intake pipe 101A on the side farther from the housing 10 than the branch point is opened, the intake pipe 101A is opened to the housing 10. communicated with the interior of the Further, when the valves V1 to V3 located on the housing 10 side of the branch point are opened, and the valve V6 provided on the liquid supply pipe 101B on the side of the branch point away from the housing 10 is opened, the liquid supply pipe 101B are communicated with the inside of the housing 10 .

First, the inside of the housing 10 is evacuated. As shown in FIG. 3, the valves V6 and V7 are closed, the valves V1 to V5 are opened, and the vacuum pump 104 is driven. In this state, the liquid supply pipe 101B is closed, and the cold trap 103 and the vacuum pump 104 of the intake pipe 101A are communicated with the inside of the housing 10. FIG. By driving the vacuum pump 104, the air inside the housing 10 is sucked out as indicated by the arrow in FIG.

Then, the coolant 20 is injected into the inside of the housing 10 . As shown in FIG. 4, valves V4 and V5 are closed and valves V1 to V3, V6 and V7 are opened. In this state, the intake pipe 101A is closed and the liquid storage tank 105 is communicated with the interior of the housing 10 . Since the air in the housing 10 is sucked out by the driving of the vacuum pump 104 and the pressure is negative, the liquid refrigerant 20L in the liquid storage tank 105 is removed from the housing 10 as indicated by the arrow in FIG. injected inside the When a predetermined amount of coolant 20 has been injected into housing 10, valves V1 to V3, V6, and V7 are closed to terminate the injection of coolant 20. FIG.

Next, the pipe 101 is closed to form a sealed space CS. Between the valve V1 provided at the position closest to the housing 10 of the pipe 101 shown in FIG. 5A and the housing 10, for example, as shown in FIG. Then, the valve V1 is detached from the pipe 101. After that, as shown in FIG. 5C, the pipe 101 is cut at a position farther from the housing 10 than the closed portion, and if necessary, the cut portion is sealed by heat welding or the like.
As described above, the electric device 1 is manufactured by forming the vacuum sealed space CS inside the housing 10 and injecting the coolant 20 therein.

(Refrigerant 20 and heat flow in electrical device 1)
Next, an example of the coolant 20 and heat flow in the electric device 1 of this embodiment will be described with reference to FIGS. 1 and 2 again.
When the electric device 1 starts to be energized, the heat-generating component 30 immersed in the liquid coolant 20L within the housing 10 generates heat. Heat generated by the FET 30A, the coil 30B, the resistor 30C, etc. is transferred to the liquid coolant 20L in contact with them. When the liquid refrigerant 20L boils due to this heat, the refrigerant 20 rises as the vaporized refrigerant 20G. The liquid refrigerant 20L heated in the vicinity of the heat-generating component 30 also decreases in specific gravity and rises without boiling. Thus, the gas-liquid two-phase flow FLG containing the vaporized refrigerant 20G and the liquid refrigerant 20L generated in the vicinity of the heat-generating component 30 rises while entraining the surrounding liquid refrigerant 20L. The heat-generating component 30 is arranged between a pair of left and

right guide members

40, 40, and since the guide member 40 is made difficult for the vaporized refrigerant 20G and the liquid refrigerant 20L to permeate, the gas-liquid two-phase flow FLG is The central portion of the housing 10 sandwiched between the pair of

guide members

40, 40 is raised. In the present embodiment, the circuit board 60 and the bus bar 70 are arranged so that their plate surfaces extend in the vertical direction and function as straightening plates. rises in the center of

By the way, when the gas rising in the liquid hits a horizontal plane from below, it cannot rise and stays below the horizontal plane. If the heat-generating component 30 is arranged in a posture in which the lower outer plane 31 is a horizontal plane (a posture in which the normal to the lower outer plane 31 is along the vertical direction), air bubbles will form below the lower outer plane 31 . stays, and there is a possibility that a portion that does not come into contact with the liquid refrigerant 20L is generated. As a result, if the heat is not properly conducted to the liquid refrigerant 20L, the temperature of the heat-generating component 30 may rise, which may lead to a malfunction or the like. In the electric device 1 according to the present embodiment, as shown in FIG. 1, the four FETs 30A are arranged at positions that do not overlap vertically on the left side of the bus bar 70 on the board surface 61A side (the front side of the housing 10), for example. ing. Therefore, the gas-liquid two-phase flow FLG containing the vaporized refrigerant 20G generated near each FET 30A can rise almost without being hindered by the other FETs 30A. On the right side of the bus bar 70, four FETs 30A and four coils 30B are arranged obliquely when viewed from the front. Therefore, the gas-liquid two-phase flow FLG containing the vaporized refrigerant 20G generated near each FET 30A can rise along the slope of the lower outer plane 31 even if it collides with the other FETs 30A and coils 30B from below. As a result, in the electric device 1, the possibility that the vaporized refrigerant 20G stays in the vicinity of the heat-generating component 30 and causes a malfunction is reduced. Note that the heat-generating component 30 whose lower outer surface is curved downward (see FIG. 2), for example, like the resistor 30C according to the present embodiment, is different from other heat-generating components 30 (for example, the FET 30A in FIG. 2). Even if the lower edge is horizontally arranged upward, the vaporized refrigerant 20G rises along the lower outer curved surface, so that it is difficult to stay in the vicinity of the heat-generating component 30 .

When the gas-liquid two-phase flow FLG rises and reaches the liquid surface of the stored liquid refrigerant 20L, the vaporized refrigerant 20G is released into the vapor phase space GS to generate a vapor phase flow FG of the vaporized refrigerant 20G. The gas-phase flow FG passes through a communication passage P1 formed above the guide member 40 and reaches the cooling wall portion 15A. Since the cooling wall portion 15A absorbs heat by the heat exchange mechanism 50 and is maintained at a low temperature, the vaporized refrigerant 20G is deprived of heat, condensed, and returns to liquid. The liquid coolant 20L adhering to the cooling wall portion 15A flows down along the left and right side walls 17 connected to the inclined wall 15 . Further, the liquid coolant 20L that is condensed and dripped in the gas phase space GS near the cooling wall portion 15A is received over a wide range on the upper surface of the upper end portion 40T, and the left and right sidewalls along the inclination of the upper end portion 40T. 17 neighborhood. Since the liquid-phase flow FL containing the liquid refrigerant 20L generated in this manner has increased specific gravity due to heat absorption, it descends between the guide member 40 and the left and right side walls 17 . In this embodiment, the entire guide member 40 is immersed in the liquid coolant 20L, and the liquid surface of the stored liquid coolant 20L is located above the upper end of the guide member 40. FIG. When the gas-liquid two-phase flow FLG rising between the pair of

guide members

40, 40 reaches the liquid surface, the liquid refrigerant 20L is further pushed by the gas-liquid two-phase flow FLG rising from below, and moves into the guide. It moves over the upper end of the member 40 to the vicinity of the side wall 17, joins the liquid phase flow FL, and descends. When the liquid-phase flow FL reaches the lower wall 11 along the guide member 40, the liquid refrigerant 20L passes through the flow path P2 formed below the guide member 40 and flows into the central portion of the housing 10, whereupon the refrigerant 20 Reflux.

As described above, the refrigerant 20 receives heat by being in direct contact with the heat-generating component 30, and changes its state from liquid to gas or vice versa. circulates through the part and the refrigerant circulation part. As the coolant 20 circulates, the heat generated in the heat generating component 30 is radiated to the outside of the electric device 1 by the heat exchange mechanism 50 via the coolant 20, the cooling wall portion 15A of the housing 10, and the like. In the electric device 1, the flow of the coolant 20 is regulated by the guide member 40 and the like, and the coolant 20 is configured to circulate smoothly.

(Action and effect of the embodiment)
The effects of this embodiment will be explained again.
The electric device 1 according to the present embodiment includes a housing 10 whose interior is a closed space CS, a liquid refrigerant 20L stored inside the housing 10, and immersed in the liquid refrigerant 20L, and heat is generated by energization. and a vaporized refrigerant 20G obtained by vaporizing the liquid refrigerant 20L due to the heat generated from the heat generating component 30 is released above the liquid refrigerant 20L inside the housing 10. A gas phase space GS is formed, and a cooling wall portion 15A of the housing 10 that is in contact with the gas phase space GS has a heat exchange mechanism that absorbs heat from the inside of the housing 10 and radiates it to the outside of the housing 10. A mechanism 50 is provided, and a guide member 40 extending in the vertical direction is provided between the side wall 17 of the housing connected to the cooling wall portion 15A and the heat generating component 30, and the inside of the sealed space CS is provided. Above the guide member 40, a communication passage P1 through which at least the vaporized refrigerant 20G can flow is formed, and below the guide member 40, a flow passage P2 through which the liquid refrigerant 20L can flow is formed. ing.

According to the configuration of the present embodiment, the guide member 40 separates and forms a refrigerant boiling portion, a refrigerant condensation portion, and a refrigerant circulation portion in the sealed space CS. Details are as follows. The liquid refrigerant 20L receives heat from the heat-generating component 30 and boils in the vicinity of the heat-generating component 30, which serves as a boiling portion of the refrigerant, and changes into a gas. A gas-liquid two-phase flow FLG containing vaporized refrigerant 20G and heated liquid refrigerant 20L thus generated rises along guide member 40 . A gas-phase flow FG containing the vaporized refrigerant 20G released from the liquid surface of the liquid refrigerant 20L into the gas-phase space GS passes through the communicating path P1 and reaches the vicinity of the cooling wall portion 15A serving as the refrigerant condensation portion. Here, the heat of the vaporized refrigerant 20G is absorbed by the heat exchange mechanism 50, condensed, and returns to liquid. The resulting liquid phase flow FL containing the liquid refrigerant 20L descends along the guide member 40 in the vicinity of the side wall 17 serving as the refrigerant recirculating portion, passes through the flow path P2, and flows through the guide member 40 serving as the refrigerant boiling portion. It flows inside from below. In this manner, the gas-liquid two-phase flow FLG flowing upward from the bottom in the central portion of the housing 10 and the liquid-phase flow FL flowing upward from the top near the side wall 17 are separated by the guide member 40, and the housing The coolant 20 smoothly circulates inside the body 10 . The heat from the heat-generating component 30 is transmitted to the heat exchange mechanism 50 through the coolant 20 circulating in this way, and the heat is radiated to the outside of the housing 10 without delay. As a result, in the electrical device 1, the heat-generating component 30 is efficiently cooled.

The electric device 1 according to the present embodiment further includes a circuit board 60 arranged inside the housing 10 , and the heat-generating component 30 is at least It is mounted on one substrate surface 61A, and the circuit substrate 60 is arranged with the normal line of the substrate surface 61 along the horizontal direction.
According to the configuration of the present embodiment, in addition to the guide member 40 extending in the vertical direction, the circuit board 60 disposed inside the housing 10 in an upright posture with the board surface 61 extending in the vertical direction also serves as the coolant 20 . It functions as a rectifying plate that regulates the flow of As a result, the coolant 20 circulates more smoothly inside the housing 10, and the heat-generating parts 30 are efficiently cooled.

The electric device 1 according to this embodiment further includes a bus bar 70 formed in a longitudinal shape that is long in one direction. Implemented.
According to the configuration of this embodiment, the bus bar 70 also functions as a rectifying plate that regulates the flow of the refrigerant 20 . As a result, the coolant 20 flows more smoothly, and the heat-generating component 30 is cooled more efficiently.

In the electric device 1 according to this embodiment, the heat-generating component 30 has a lower outer plane 31 located on the lower side of the outer surface of the heat-generating component 30 , and the lower outer plane 31 is perpendicular to the substrate surface 61 . It is mounted on the substrate surface 61 in an inclined posture when viewed from the line direction.
According to the configuration of the present embodiment, even when the plane forming the outer surface of the heat-generating component 30 is positioned below the heat-generating component 30, that is, when the heat-generating component 30 has the lower outer plane 31, Even so, since the lower outer plane 31 is arranged in an inclined manner, the vaporized refrigerant 20G rises around the heat-generating component 30 along the lower outer plane 31 . Therefore, it is possible to reduce the occurrence of a situation in which the vaporized refrigerant 20G stays and the cooling of the heat-generating component 30 is hindered.

The electric device 1 according to this embodiment includes a plurality of heat-generating components 30, and the heat-generating components 30 are mounted on both substrate surfaces 61, ie, one substrate surface 61A and the other substrate surface 61B.
According to the configuration of this embodiment, the heat-generating components 30 are mounted on both

board surfaces

61A and 61B of the circuit board 60. As shown in FIG. As a result, the mounting density of the heat-generating components 30 on the circuit board 60 can be improved without excessively narrowing the space between the adjacent heat-generating components 30 , and the size of the electric device 1 can be reduced.

In the electric device 1 according to this embodiment, the upper end portion 40T of the guide member 40 is inclined upward in a direction away from the side wall 17 .
According to the configuration of the present embodiment, the upper end portion 40T of the guide member 40 is inclined toward the heat-generating component 30 side toward the center of the substrate surface 61 in the left-right direction. As a result, the liquid coolant 20L dripping from above can be received over a wide range on the upper surface of the upper end portion 40T and guided to the side wall 17 side.

In the electric device 1 according to this embodiment, the housing 10 has an inclined wall 15 that connects the side wall 17 and the upper wall 13 while being inclined, and the cooling wall portion 15A is provided on the inclined wall 15. It is
According to the configuration of this embodiment, most of the liquid refrigerant 20L generated by condensation of the vaporized refrigerant 20G in contact with the cooling wall portion 15A is guided along the inclined wall 15 and the side wall 17 to the refrigerant return flow portion.

In the electric device 1 according to this embodiment, the gas phase space GS is evacuated.
According to the configuration of this embodiment, the boiling point of the liquid refrigerant 20L can be lowered below that under normal pressure, and the boiling efficiency of the liquid refrigerant 20L and thus the cooling efficiency of the heat-generating component 30 can be improved.

<Other embodiments>
The present disclosure is not limited to the embodiments described by the above description and drawings, and for example, the following embodiments are also included in the technical scope of the technology disclosed in this specification.

(1) The heat generating component 30 is not limited to the above. The dimensions, number, and arrangement of the heat-generating components 30 described in the above embodiment are merely examples. In this embodiment, the arrangement of the heat-generating components 30 mounted on one substrate surface 61A and the arrangement of the heat-generating components 30 mounted on the other substrate surface 61B are different. The arrangement of the heat-generating components 30 on the other substrate surface 61B may be the same.

(2) The circuit board 60 and the housing 10 are not limited to those having the dimensions and shapes described above. In the above-described embodiment, the vertically long circuit board 60 and housing 10 whose vertical height dimension is greater than their horizontal width dimension have been described. For example, a horizontally elongated circuit board and housing may be used in which the left and right width dimensions are larger than the top and bottom height dimensions. In this way, it is possible to increase the area of the cooling wall portion and obtain higher cooling efficiency.

(3) The shape, number, and arrangement of the busbars 70 are not limited to those described above. For example, a plurality of bus bars may be arranged on both one substrate surface and the other substrate surface of the circuit board. Also, a plurality of bus bars may be arranged side by side in parallel so as to extend in the vertical direction at intervals in the left-right direction on one substrate surface or both substrate surfaces of the circuit board. By doing so, the flow of the coolant can be further adjusted.

(4) The electric device 1 is not limited to one including a DC-DC converter. For example, the present technology can be applied to AC-DC converters, electric connection boxes, distribution boxes, ECUs, and the like.

1: Electric equipment 10: Case 11: Bottom wall 13: Top wall 15: Inclined wall 15A: Cooling wall part 17: Side wall 17L: Left side wall 17R: Right side wall 19B: Rear wall 19F: Front wall 20: Refrigerant 20G: Vaporization Refrigerant 20L: Liquid refrigerant 30: Heat generating component 30A: FET
30B: Coil 30C: Resistance 31: Lower outer plane 31A: (One) lower outer plane 31B: (Other) lower outer plane 40: Guide member 40T: Upper end 50: Heat exchange mechanism 51: Cooling pipe 60 : Circuit board 61: Board surface 61A: (One) substrate surface 61B: (Other) substrate surface 70: Bus bar 101: Pipe 101A: Intake pipe 101B: Liquid supply pipe 103: Cold trap 104: Vacuum pump 105: Liquid storage Tank CS: Closed space GS: Gas phase space FG: Gas phase flow FL: Liquid phase flow FLG: Gas-liquid two-phase flow P1: Communication path P2: Flow path

Claims

a housing having an enclosed space inside;
a liquid coolant stored inside the housing;
At least one heat generating component that is immersed in the liquid refrigerant and generates heat when energized,
A gas phase space is formed above the liquid coolant inside the housing, in which vaporized coolant obtained by vaporizing the liquid coolant due to heat generated by the heat-generating component is released,
The cooling wall portion of the housing that is in contact with the gas phase space is provided with a heat exchange mechanism that absorbs heat from the inside of the housing and radiates heat to the outside of the housing,
A guide member extending in the vertical direction is provided between the side wall of the housing connected to the cooling wall portion and the heat-generating component,
Inside the closed space, a communication path through which at least the vaporized refrigerant can flow is formed above the guide member, and a flow path through which the liquid refrigerant can flow is formed below the guide member. There is an electrical device.
Further comprising a circuit board arranged inside the housing,
The heat-generating component is mounted on at least one of two board surfaces of the circuit board,
2. The electric device according to claim 1, wherein said circuit board is arranged in a posture in which a normal line of said board surface is horizontal.
further comprising a busbar formed in a longitudinal shape long in one direction,
3. The electric device according to claim 2, wherein said bus bar is mounted on said circuit board in such a posture that the longitudinal direction of said bus bar is in the vertical direction.
The heat-generating component has a flat lower outer plane positioned on the lower side of the outer surface of the heat-generating component, and the lower outer plane is positioned above the substrate surface in an inclined posture when viewed from the normal direction of the substrate surface. 4. The electrical equipment according to claim 2 or 3, which is mounted in a
comprising a plurality of the heat-generating components,
The electric device according to any one of claims 2 to 4, wherein the heat-generating component is mounted on both the one substrate surface and the other substrate surface.
The electric device according to any one of claims 1 to 5, wherein the upper end portion of the guide member is inclined upward in a direction away from the side wall.
The housing has an inclined wall that connects the side wall and the upper wall while being inclined,
The electric device according to any one of claims 1 to 6, wherein the cooling wall portion is provided on the inclined wall.
The electric device according to any one of claims 1 to 7, wherein the gas phase space is evacuated.