JP5903548B2 - COOLING DEVICE, ELECTRONIC DEVICE WITH THE SAME, AND ELECTRIC CAR - Google Patents

Description

  The present invention relates to a cooling device, an electronic device equipped with the cooling device, and an electric vehicle.

  Conventionally, this type of cooling device is known to be mounted on a power conversion circuit of an electric vehicle. In an electric vehicle, an electric motor serving as a driving power source is switched by an inverter circuit that is a power conversion circuit. A plurality of semiconductor switching elements represented by power transistors are used in the inverter circuit, and a large current of several tens of amperes flows through each element. Therefore, the semiconductor switching element generates a large amount of heat and needs to be cooled.

  Therefore, conventionally, as in Patent Document 1, for example, a boil cooling device having a refrigerant radiator and a refrigerant tank at the top and bottom has cooled an inverter circuit arranged at the bottom.

JP-A-8-126125

  In such a conventional cooling device, the refrigerant tank is disposed in contact with the semiconductor switching element, and the liquefied refrigerant in the refrigerant tank is vaporized by taking heat from the switching element.

  And the cycle which raises the vaporized refrigerant | coolant to the refrigerant | coolant heat radiator arrange | positioned at the upper part, cools, liquefies, and is dripped again at the lower part is repeated. In other words, the refrigerant circulates by natural convection.

  However, in such a natural convection type, the heat of the switching element can be simply transferred to the liquefied refrigerant stored in the refrigerant tank through the wall (heat transfer surface) of the refrigerant tank by simple heat conduction. Therefore, the heat transfer efficiency on the heat transfer surface cannot be increased, and as a result, the cooling effect of the switching element or the like cannot be increased.

  Then, this invention aims at heightening the cooling effect by raising the heat-transfer efficiency in a heat-transfer surface.

In order to achieve this object, the present invention provides a heat receiving portion including a heat receiving plate that transfers heat from the heating element to the working fluid, a heat radiating portion that releases the heat of the working fluid, the heat receiving portion, and the heat receiving portion. A heat dissipation path connecting the heat dissipation part and a return path are configured, and the working fluid is circulated to the heat receiving part, the heat dissipation path, the heat dissipation part, the return path, and the heat receiving part to transfer heat. A cooling device, an inflow pipe for supplying the working fluid into the heat receiving section is connected to the heat receiving section side of the return path, and a check valve is provided at a connection section between the heat receiving section and the inflow pipe to vaporize the cooling path. The working fluid liquefied by the check valve being pushed down due to the difference between the pressure in the heat receiving portion whose amount has decreased and the pressure of the working fluid accumulated on the check valve is supplied onto the heat receiving plate. And the working fluid supplied onto the heat receiving plate The thin film is diffused from the gap between the end opening of the inflow pipe and the heat receiving plate to the outer peripheral portion and spreads as a thin film on the heat receiving plate. The inner wall of the inflow pipe has a thermal conductivity higher than that of the material constituting the inflow pipe. A low thermal insulation coating portion is prepared for the volume of the working fluid to generate at least the hydraulic head pressure that pushes the check valve open, thereby achieving the intended purpose.

According to the present invention, a heat receiving portion including a heat receiving plate that transfers heat from the heat generating element to the working fluid, a heat radiating portion that releases the heat of the working fluid, and a heat radiating path that connects the heat receiving portion and the heat radiating portion. And a return path, wherein the working fluid is circulated to the heat receiving part, the heat radiating path, the heat radiating part, the return path, and the heat receiving part to transfer heat, An inflow pipe for supplying the working fluid into the heat receiving section is connected to the heat receiving section side of the path, and a check valve is provided at a connection section between the heat receiving section and the inflow pipe, and the amount of vaporization is reduced in the heat receiving section. The working fluid liquefied by the check valve being pushed down due to the difference between the pressure and the pressure of the working fluid accumulated on the check valve is supplied onto the heat receiving plate and supplied onto the heat receiving plate. The working fluid that has flowed through the end opening of the inlet pipe Spread on the heat receiving plate as a thin film is diffused into the outer peripheral portion from the gap of the heat receiving plates, the the inner wall of the inlet tube, at least the non-return low adiabatic Kotin unit thermal conductivity than the material constituting the inlet pipe Since it is prepared for the volume of the working fluid to generate the hydraulic head pressure that pushes the valve open, the cooling effect can be enhanced.

  That is, in the present invention, the circulation path of the working fluid serving as a refrigerant is a heat receiving portion, a heat radiating route, a heat radiating portion, a return route, and the heat receiving portion. An inflow pipe for supplying the working fluid into the heat receiving section is connected to the heat receiving section side of the return path, and a check valve is provided at a connection section between the heat receiving section and the inflow pipe to reduce the amount of vaporization in the heat receiving section. The working fluid liquefied by the check valve being pushed down due to the difference between the pressure and the pressure of the working fluid accumulated on the check valve is supplied onto the heat receiving plate and supplied onto the heat receiving plate. The working fluid is diffused from the gap between the end opening of the inflow pipe and the heat receiving plate to the outer peripheral portion and spreads as a thin film on the heat receiving plate, so that the working fluid is rapidly vaporized in the heat receiving portion. Working flow in the heat receiving plate Forcefully it can be moved, as a result enhancing the heat transfer efficiency in the heat transfer surface as can be enhanced cooling effect.

In the present invention, the inner wall surface of the inflow pipe provided on the inlet side of the heat receiving part is provided with a heat insulating coating coated with a material having low thermal conductivity , so that the working fluid is passed through the check valve through the heat receiving part. It can be kept in a liquid state until it is introduced into the liquid.

  For this reason, since the working fluid flows into the heat receiving portion as a liquid, as described above, the working fluid can be rapidly vaporized in the heat receiving portion, and the working fluid can be moved vigorously in the heat receiving plate portion. As a result, the heat transfer efficiency on the heat transfer surface can be increased and the cooling effect can be increased.

Schematic of the electric vehicle according to the first embodiment of the present invention. Diagram showing the structure of the radiator Schematic showing the cooling system Heat receiving part perspective view of the cooling device Cross section of heat receiving part of the cooling device

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, an electric motor (not shown) that drives an axle (not shown) of an electric vehicle 1 is connected to an inverter circuit 2 that is a power conversion device arranged in the electric vehicle 1.

  The inverter circuit 2 supplies electric power to the electric motor, and includes a plurality of semiconductor switching elements (10 in FIG. 3). The semiconductor switching elements (10 in FIG. 3) generate heat during operation.

  For this reason, in order to cool this semiconductor switching element (10 in FIG. 3), a cooling device 3 is provided. The cooling device 3 includes a heat receiving portion 4 and a heat radiating portion 5 that radiates heat absorbed by the heat receiving portion 4, and a working fluid (12 in FIG. 3) serving as a heat medium between the heat receiving portion 4 and the heat radiating portion 5. For example, by providing the heat radiation path 6 and the return path 7 for circulating water), the heat receiving section 4, the heat radiation path 6, the heat radiation section 5, the feedback path 7, and the circulation path serving as the heat receiving section 4 are configured.

  That is, in this circulation path, the working fluid (12 in FIG. 3) is a gas (water vapor in the case of water) or a liquid and a mixed state thereof, the heat receiving part 4, the heat radiation path 6, the heat radiation part 5, the return path 7, It circulates in one direction with the heat receiving part 4.

  As shown in FIG. 2, the heat dissipating part 5 includes a heat dissipating body 8 that releases heat to the outside air.

  The heat dissipating body 8 includes a block body in which fins formed by thinly forming aluminum in a strip shape are stacked at a predetermined interval, and a heat dissipating path 6 penetrating the stacked fins.

  And heat is radiated by blowing outside air from the blower 9 onto the surface of the radiator 8. The heat radiation from the surface of the heat radiating body 8 can also be utilized for heating in the electric vehicle 1.

  Further, as shown in FIG. 3, the heat receiving section 4 is in contact with the semiconductor switching element 10 to absorb heat and a heat receiving space that covers the surface of the heat receiving plate 11 and evaporates the flowing working fluid 12. And a heat-receiving plate cover 14 that forms 13.

  Furthermore, the heat receiving plate cover 14 is provided with an inlet 15 for flowing the liquefied working fluid 12 into the heat receiving space 13 and an outlet 16 for discharging the working fluid 12 from the heat receiving space 13 as a gas.

  In FIG. 3, although the said heat receiving part 4 was shown typically, it has a structure as specifically shown in FIG. 4, FIG.

  That is, the inlet 15 and the outlet 16 are provided on the upper surface of the heat receiving plate cover 14, the return path 7 is connected to the inlet 15, and the heat dissipation path 6 is connected to the outlet 16.

  Further, an inflow pipe 19 for supplying the working fluid 12 into the heat receiving portion 4 is connected to the heat receiving portion 4 side of the return path 7 in a state of protruding into the heat receiving space 13, and the heat receiving portion 4. A check valve 18 is provided at a connection portion between the inlet 15 and the inlet pipe 19. Hereinafter, the inflow pipe 19 in the heat receiving space 13 is referred to as an introduction pipe 17.

The inner wall of the inflow pipe 19 was coated with a coating material (heat-resistant resin) having a lower thermal conductivity than the material (for example, copper) constituting the inflow pipe 19. Let the coated part be a heat insulation coating part.

  The operation of the cooling device 3 having such a configuration will be described.

  In the above configuration, when the semiconductor switching element 10 of the inverter circuit 2 starts to operate, electric power is supplied to the electric motor, and the electric vehicle 1 starts to move.

  At this time, when a large current flows through the semiconductor switching element 10, at least several percent of the total power is lost and a large amount of heat is generated.

  On the other hand, when the heat generated from the semiconductor switching element 10 is transferred from the semiconductor switching element 10 to the liquid working fluid 12 supplied onto the heat receiving plate 11 of the heat receiving space 13, the liquid working fluid is heated. 12 is vaporized in an instant, flows from the discharge port 16 to the heat radiation path 6, and releases heat to the outside air by the heat radiation portion 5.

  The working fluid 12 that has released heat by the action of the heat radiating unit 5 is liquefied and flows to the return path 7 and accumulates on the check valve 18 of the inflow port 15.

  While the liquefied working fluid 12 gradually increases in the return path 7, the vaporization amount of the working fluid 12 in the heat receiving space 13 decreases, the pressure in the heat receiving space 13 also decreases, and the pressure on the check valve 18 is increased. When the check valve 18 is pushed down by the pressure of the accumulated working fluid 12 due to the water head, it is supplied again onto the heat receiving plate 11 in the heat receiving space 13.

  In this way, the working fluid 12 circulates in the cooling device 3 to cool the semiconductor switching element 10.

  Here, the cooling mechanism in the heat receiving space 13 will be described.

  In the heat receiving space 13, the working fluid 12 from the return path 7 is dropped as droplets from the introduction pipe 17 onto the heat receiving plate 11. The dropped working fluid 12 is diffused from the gap between the end opening of the return path 7 and the heat receiving plate 11 to the outer periphery.

  At this time, since the surface of the heat receiving plate 11 has a shape in which the flow path radially expands, the working fluid 12 spreads on the heat receiving plate 11 as a thin film. Since the back surface side of the heat receiving plate 11 is in contact with the semiconductor switching element 10, the working fluid 12 that has become a thin film is heated and vaporized in an instant.

  Since the atmospheric pressure in the circulation path including the heat receiving space 13 is set lower than the atmospheric pressure, the working fluid 12 is vaporized at a temperature lower than the boiling of water in the atmospheric pressure even if water is used. Can do.

  As in the present embodiment, by setting the atmospheric pressure to −97 KPa and keeping the inside of the circulation path saturated, the boiling temperature according to the outside air temperature is determined and water can be easily vaporized. The semiconductor switching element 10 can be deprived of heat and cooled.

  Further, when the working fluid 12 is vaporized, the pressure in the heat receiving space 13 increases. However, the working fluid 12 does not flow back to the return path 7 due to the action of the check valve 18, and the discharge port 16 is surely provided. To the heat dissipation path 6.

  By operating the cooling device 3 in this manner, a regular heat receiving and releasing cycle can be performed, and the working fluid 12 can be continuously vaporized in the heat receiving space 13 to cool the semiconductor switching element 10. A large cooling effect can be obtained.

  Here, the most characteristic part of the present invention will be described.

  As described above, on the upstream side immediately before the check valve 18 in the return path 7 (hereinafter, this portion is referred to as the inflow pipe 19), the working fluid 12 before dropping into the heat receiving space 13 remains as a liquid. Will be.

  In order to drop the working fluid 12 in the heat receiving space 13 as a liquid, it is important not to apply heat in the inflow pipe 19 to vaporize the working fluid 12. For this purpose, a heat insulating material 20 is provided on the inner wall of the inflow pipe 19 and the surface exposed to the inflow pipe side of the check valve 18 so that the heat of the wall surface of the inflow pipe 19 transmitted from the heat receiving portion 4 is not applied to the working fluid 12. Coating.

  When the heat insulating material 20 is not coated, the heat of the semiconductor switching element 10 received by the heat receiving plate 11 vaporizes the working fluid 12 in the heat receiving space 13 and passes through the heat receiving plate cover 14 from the heat receiving space 13 where the temperature has risen. It is transmitted to the return path 7, that is, the inflow pipe 19.

  However, in the present embodiment, since the heat insulating material 20 is provided on the inner wall portion including the check valve 18 in the inflow pipe 19 portion, heat is transmitted to the working fluid 12 accumulated in the inflow pipe 19 portion. It has become difficult.

  Therefore, the working fluid 12 is not vaporized in the inflow pipe 19, and the working fluid 12 remains liquid in the inflow pipe 19.

  Accordingly, since the working fluid 12 that has passed through the return path 7 flows into the heat receiving space 13 as a liquid, the working fluid 12 is vaporized in the heat receiving space 13 at a stretch and becomes a pressure at which the working fluid 12 moves in the circulation path. It is.

  In addition, when heat is transferred to the working fluid 12 accumulated in the inflow pipe 19 and the working fluid 12 is vaporized in the inflow pipe 19, a reverse flow occurs in the circulation path, and the vaporized working fluid 12 is returned from the inflow pipe 19 to the return path. However, in the configuration shown in the present embodiment, the backflow from the inflow pipe 19 to the heat dissipating part 5 is suppressed. be able to.

  The heat insulating material 20 uses a heat resistant resin having a lower thermal conductivity than the wall surface (for example, copper) forming the inflow pipe 19.

  Moreover, the heat insulating material 20 should just be what forms an inner wall surface, such as not only by the thing by coating but affixing or press-fitting.

Furthermore, the surface of the heat insulating material 20 may be coated with a water-repellent material, for example, Teflon (registered trademark). Since the working fluid 12 moves on the wall surface without resistance by the water repellent coating portion 21, the working fluid 12 smoothly flows to the inflow port 15. And since the pressure loss in a circulation path can be made small as a whole and the flow volume of the working fluid 12 can be ensured, the semiconductor switching element 10 can be cooled efficiently.

  Note that the longer the length of the portion that becomes the inflow pipe 19, that is, the portion that coats the heat insulating material 20, the better the performance, but at least the volume of the working fluid 12 that generates the hydraulic head pressure that pushes the check valve 18 open. The minutes may be coated with a heat insulating material 20.

  Next, the inside of the heat receiving space 13 will be described.

The inner wall surface of the heat receiving plate cover 14 and the introduction pipe 17 below the check valve 18 are coated with a heat insulating material 20, and the surface of the heat insulating material 20 is coated with a water repellent material, for example, Teflon (registered trademark). It is coated (water repellent coating portion 21). The water repellent coating portion 21 may be applied also to the inner wall surface of the heat dissipation path 6. With this configuration, heat transfer from the heat receiving space 13 to the refrigerant in the inflow pipe 19 can be reduced.

  Moreover, the effect | action in the heat receiving space 13 by such a structure is demonstrated. In the heat receiving space 13, as described above, the working fluid 12 dropped on the heat receiving plate 11 spreads on the heat receiving plate 11 as a thin film so as to diffuse the surface of the heat receiving plate 11 around. And the working fluid 12 which became a thin film | membrane by receiving the heat | fever of the heat-receiving plate 11 which became hot will be heated and vaporized in an instant.

However, not all of the working fluid 12 is vaporized, and the working fluid 12 moves to the discharge port 16 while remaining partially liquid. At this time, the working fluid 12 moves to the discharge port 16 while being in contact with the inner wall surface of the heat receiving plate cover 14 provided with the water repellent coating portion 21.

  Therefore, the resistance in movement in the heat receiving space 13 can be suppressed to be small, and pressure loss due to movement of the working fluid 12 can be suppressed. That is, since the working fluid 12 can flow smoothly, it can be cooled efficiently.

In addition, about the water-repellent coating part 21 in the heat radiation path | route 6, although the whole path | route may be coated, about the part away from the heat receiving plate cover 14, ie, the part which is hard to be influenced by the heat of the heat receiving plate 11, The same action and effect can be obtained by using a material with low wall resistance.

In the above-described embodiment, the case where the surface of the heat insulating material 20 is the water repellent coating portion 21 has been described. However, even if the heat insulating material 20 itself has water repellency, the same action and effect are obtained.

  In the above embodiment, the cooling device 3 applied to the electric vehicle 1 has been described. However, the inverter circuit 2 that is a power conversion device is also an electronic device, and the cooling device 3 can be applied to the electronic device. .

  The cooling device according to the present invention has a circulation path of the working fluid as one direction by setting a circulation path of the working fluid serving as a refrigerant as a heat receiving section, a heat radiation path, a heat radiation section, a return path, and the heat receiving section. An inflow pipe that supplies the working fluid into the heat receiving part is connected to the heat receiving part side of the return path, and a check valve is provided at a connection part between the heat receiving part and the inflow pipe, so that the working fluid is supplied in the heat receiving part. It is possible to rapidly vaporize and move the working fluid vigorously in the heat receiving plate portion. As a result, the heat transfer efficiency on the heat transfer surface can be increased and the cooling effect can be increased.

  In the present invention, since the inner wall surface of the inflow pipe provided on the inlet side of the heat receiving part is coated with a material having low thermal conductivity, the working fluid is introduced into the heat receiving part via the check valve. It can be kept in a liquid state.

  For this reason, as described above, the working fluid can be rapidly vaporized in the heat receiving portion, and the working fluid can be moved vigorously in the heat receiving plate portion. As a result, the heat transfer efficiency on the heat transfer surface can be improved and the cooling effect can be improved. be able to.

  For this reason, it is useful for cooling power semiconductors used in power conversion devices as drive devices for electric vehicles, CPUs with high heat generation, and the like.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Inverter circuit 3 Cooling device 4 Heat receiving part 5 Heat radiating part 6 Heat radiating path 7 Return path 8 Heat radiating body 9 Blower 10 Semiconductor switching element 11 Heat receiving plate 12 Working fluid 13 Heat receiving space 14 Heat receiving plate cover 15 Inlet 16 Outlet 17 Introducing pipe 18 Check valve 19 Inflow pipe 20 Heat insulating material 21 Water repellent coating part

Claims (6)

A heat receiving section having a heat receiving plate for transferring heat from the heating element to the working fluid;
A heat dissipating part for releasing the heat of the working fluid;
Consists of a heat dissipation path and a return path connecting the heat receiving section and the heat dissipation section,
A cooling device that circulates the working fluid to the heat receiving unit, the heat dissipation path, the heat dissipation unit, the return path, and the heat receiving unit to transfer heat,
On the heat receiving part side of the return path, an inflow pipe for supplying the working fluid is connected in the heat receiving part, and a check valve is provided at a connection part between the heat receiving part and the inflow pipe,
The working fluid liquefied by the check valve being pushed down due to the difference between the pressure in the heat receiving portion where the amount of vaporization has decreased and the pressure due to the head of the working fluid accumulated on the check valve is placed on the heat receiving plate. Supplied,
The working fluid supplied onto the heat receiving plate is diffused from the gap between the end opening of the inflow pipe and the heat receiving plate to the outer peripheral portion and spreads as a thin film on the heat receiving plate,
On the inner wall of the inflow pipe, a heat insulating coating portion having a lower thermal conductivity than the material constituting the inflow pipe is provided for the volume of the working fluid to generate at least the hydraulic head pressure that pushes the check valve open . A cooling device characterized by that. The cooling device according to claim 1, further comprising a heat insulating coating portion having a lower thermal conductivity than a material constituting the check valve on a surface exposed to the inflow pipe side of the check valve. The cooling apparatus according to claim 1, wherein the heat insulating coating portion has water repellency. Cooling apparatus according to claim 1, wherein further comprising a water-repellent coating of the water repellent onto the thermal barrier coating unit. An electronic apparatus comprising the cooling device according to claim 1. An electric vehicle comprising the cooling device according to any one of claims 1 to 4.

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