JP5799205B2 - 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, provided in the vicinity of the heat receiving portion of the return path or in the heat receiving portion, a valve body for controlling the flow of the working fluid, and a check valve constituted by a valve holder for holding the valve body; The movable part of the valve body is movable in the valve holder, and the working fluid receives and vaporizes in the heat receiving part to increase the pressure in the heat receiving part, whereby the check valve is closed by the movable part, Vaporization amount of the working fluid in the heat receiving part The pressure due to decrease water head of the working fluid with reduced pressure accumulated on said check valve in said heat receiving portion due to the check valve is configured to open by the movable unit, thereby achieving the desired object To do.

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, 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, and the heat receiving part of the return path A check valve composed of a valve main body for controlling the flow of the working fluid and a valve holder for holding the valve main body is provided in the vicinity of the part or in the heat receiving part, and the movable part of the valve main body is disposed in the valve holder. The check valve is closed by the movable part and the amount of vaporization of the working fluid is reduced in the heat receiving part by moving and receiving and vaporizing the working fluid in the heat receiving part and increasing the pressure in the heat receiving part. Pressure drop in the heat receiving part Wherein the pressure due to water head of the working fluid that has accumulated on the check valve, so is obtained by said check valve open configuration by the movable part, it is possible to enhance the cooling effect.

  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 that supplies the working fluid into the heat receiving section is connected to the heat receiving section side of the return path, and a check valve that controls the flow of the working fluid is provided at the tip of the inflow pipe.

  The movable part of the valve body of the check valve is opened in the valve holder, and the valve body is opened by the pressure of the working fluid accumulated on the valve body, that is, the movable part of the valve body is movable in the valve holder. Therefore, the opening state is not excessive, and as a result, the working fluid is not supplied excessively into the heat receiving portion, and the supply of the working fluid can be controlled appropriately. Spreads on the heat receiving plate as a thin film to diffuse to the surroundings, receives the heat of the heated heat receiving plate, and is instantly heated and vaporized, increasing the heat transfer efficiency on the heat transfer surface and enhancing the cooling effect be able to.

  Furthermore, the volume expansion by the vaporization allows the working fluid to move vigorously in the heat receiving plate portion, and 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. Schematic showing the cooling system Exploded perspective view showing the check valve Partially cut perspective view showing the check valve Schematic which shows the cooling device of Embodiment 2 of this invention. (A) Exploded perspective view showing the check valve, (b) Assembly perspective view showing the check valve, (c) Perspective view showing a cross section of the check valve (A) Schematic configuration diagram of the check valve mounting portion, (b) Expanded configuration diagram showing the check valve mounting portion

  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. 2). The semiconductor switching elements (10 in FIG. 2) generate heat during operation.

  For this reason, in order to cool this semiconductor switching element (10 in FIG. 2), 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. 2) 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. 2) 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 (not shown) 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. 2, the heat receiving portion 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.

  That is, the inlet 15 is provided on the upper surface of the heat receiving plate cover 14, and the outlet 16 is provided on the side 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. Connected.

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

  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 in the introduction pipe 17.

  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 check valve 18 onto the heat receiving plate 11.

  At this time, the surface of the heat receiving plate 11 has a shape in which the flow path radially expands, and an appropriate amount of the working fluid 12 can be supplied by the action of a check valve 18 described later, so that the supplied working fluid 12 is a thin film as the heat receiving plate. 11 spreads over. 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.

  In this embodiment, the atmospheric pressure is set to −97 KPa and the inside of the circulation path is saturated, so that the boiling temperature corresponding to the outside air temperature is determined and water can be easily vaporized. The 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 shown in the exploded view of FIG. 3, the check valve 18 includes a valve main body 21 that controls the flow of the working fluid, a valve holder 22 that holds the valve main body 21, and a valve cover 23. The cover 23 is provided with holes 22 a and 23 a having the same diameter as the inner diameter of the inflow pipe 19.

  The material of the valve body 21 is copper, brass or SUS, and the thickness is 100 to 200 μm.

  As shown in the assembly diagram of FIG. 4, the valve body 21 is fixed by being sandwiched between the valve holder 22 and the valve cover 23 so that the movable portion 21 a can be received in the recess 22 b of the valve holder 22. Although not shown, it is fixed with screws or the like.

  Thereby, the movable part 21a of the valve body 21 is movable only in the recess 22b of the valve holder 22, the depth of the recess 22b is about 1 to 2 mm, and the movable part 21a and the inner wall of the recess 22b of the valve holder 22 The gap is about 1 to 2 mm, and even if the check valve 18 is opened, the working fluid 12 is not excessively supplied into the heat receiving portion 4, and the supply of the working fluid 12 can be controlled to an appropriate amount.

  Then, the working fluid 12 dropped onto 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 to the surroundings as described above, and receives the heat of the heat receiving plate 11 that has become hot, It will be heated and vaporized in an instant, increasing the heat transfer efficiency on the heat transfer surface and enhancing the cooling effect.

  Furthermore, the volume expansion due to the vaporization allows the working fluid to be vigorously moved to the discharge port 16 in the heat receiving plate portion, and 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 embodiment, the check valve 18, that is, the valve main body 21 is installed substantially horizontally. However, the installation direction may be oblique or substantially vertical as long as the valve main body 21 can be moved by the pressure of the hydraulic head of the working fluid 12. However, considering the responsiveness (relationship between the amount of the working fluid 12 and the pressure due to the water head), substantially horizontal is preferable.

(Embodiment 2)
FIG. 5 shows a cooling device 30 provided with a plurality of check valves 38, and FIG. 6 shows the configuration of the check valves 38. Constituent elements similar to those in the first embodiment (FIG. 2) are denoted by the same reference numerals, and detailed description thereof is omitted.

  As described above, on the upstream side immediately before the check valve 38 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. In general, the check valve 38 is opened at a time interval of several seconds or less, and the working fluid 12 is supplied into the heat receiving space 13.

  The problem here is the durability of the valve body 31. That is, the check valve 38 is pushed up (closed) by increasing the pressure in the heat receiving space 13 due to the vaporization of the working fluid 12 in the heat receiving space 13, and the amount of vaporization of the working fluid 12 in the heat receiving space 13 is reduced. The pressure in the heat receiving space 13 also decreases, and the check valve 38 is pushed down (opened) by the pressure of the hydraulic head of the working fluid 12 accumulated on the check valve 38, thereby repeating the movement of the movable portion 31 a of the valve body 31. The root 31b may be damaged. Furthermore, even if the valve body 31 is made of the above-described material such as copper in consideration of durability, erosion (erosion phenomenon) due to cavitation (cavity phenomenon) in the heat receiving space 13 at the time of closing occurs, and pinholes or the like occur. May result in holes.

  When the valve main body 31 is thus damaged, the check valve 38 has no valve function, the working fluid 12 is always supplied into the heat receiving space 13, and the working fluid 12 is a thin film on the surface of the heat receiving plate 11. As a result, the working fluid 12 does not spread on the heat receiving plate 11, and the heat transfer efficiency of the heat receiving plate 11 is reduced.

  In order to prevent a decrease in heat transfer efficiency of the heat receiving plate 11, in this embodiment, a check valve mounting portion 40 on which a plurality of check valves 38 are stacked is provided.

  As shown in FIG. 6, the configuration of the check valve 38 is configured so that the valve main body 31 is accommodated in the recess 32 a of the valve holder 32, because a plurality of the check valves 38 are stacked, so that the valve body 31 is upside down. As shown in FIG. 5, a hole position having the same diameter as the inner diameter of the inflow pipe 19 provided in the valve holder 32 of the check valve 38n closest to the heat receiving portion 4, ie, the lowermost stacked stage. By aligning the position of the inlet 15 of the heat receiving part 4, the movable part 31 a of the valve main body 31 can be moved only within the concave part 32 a of the valve holder 32, as with the other check valves 38 a.

  Next, the operation when two check valves 38a and 38b are loaded in the check valve mounting portion 40 will be described with reference to FIG.

  When the working fluid 12 is supplied from the inflow pipe 19 via the check valves 38 a and 38 b and heat generation is started from the semiconductor switching element 10, the liquid working fluid 12 on the heat receiving plate 11 is vaporized, thereby receiving heat. The pressure in the space 13 increases and the lower check valve 38b is pushed up (closed), but the movable portion 31a of the valve body 31 of the upper check valve 38a is recessed in the valve holder 32 filled with the working fluid 12. It will remain floating in the space.

  Next, when the amount of vaporization of the working fluid 12 in the heat receiving space 13 decreases and the pressure in the heat receiving space 13 decreases, the check valve is caused by the pressure of the head of the working fluid 12 accumulated on the check valve 38b. 38 b is pushed down (opened) to supply the working fluid 12 into the heat receiving space 13.

  As described above, regarding the normal operation when two check valves 38a and 38b are loaded inside the check valve mounting portion 40, the check valve 38a is a check valve as compared with the case of one check valve 38b. There is no function, there is no influence of erosion (erosion phenomenon) due to cavitation (cavity phenomenon) in the heat receiving space 13 due to damage to the root of the movable part of the valve body 21 due to repeated opening and closing operations in the almost open state. The check valve 38a functions as a check valve only when the check valve 38b deteriorates due to long-term use and can no longer function as the check valve.

  Thus, when the check valve 38b is damaged or has a hole or the like, the check valve 38a performs the same operation as the check valve 38b as described above, and delays maintenance time such as replacement of the check valve 38. Can do. In other words, it is possible to lengthen the period of periodic inspections.

  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. A check valve comprising a valve body for controlling the flow of the working fluid and a valve holder for holding the valve body is provided in the vicinity of or within the heat receiving part of the return path, and the movable part of the valve body Can move the inside of the valve holder to supply an appropriate amount of working fluid to the heat receiving part, so that the supplied working fluid can be rapidly vaporized, and the working fluid can be moved vigorously in the heat receiving plate part. As a result, the heat transfer efficiency on the heat transfer surface can be increased and the cooling effect can be increased.

  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 Inlet pipe 18, 38, 38a, 38b, 38m, 38n Check valve 19 Inflow pipe 21 Valve body 21a Movable part 22 Valve holder 22a, 23a Hole 22b Recess 23 Valve cover 30 Cooling device 32 Valve holder 32a Recess

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 portion, the heat radiating path, the heat radiating portion, the return path, and the heat receiving portion to move heat;
A check valve comprising a valve body for controlling the flow of the working fluid and a valve holder for holding the valve body is provided in the vicinity of or within the heat receiving part of the return path, and the movable part of the valve body Moves inside the valve holder ,
When the working fluid receives heat and vaporizes in the heat receiving part and the pressure in the heat receiving part increases, the check valve is closed by the movable part,
The check valve is opened by the movable portion due to a decrease in pressure in the heat receiving portion due to a decrease in the amount of vaporization of the working fluid in the heat receiving portion and a pressure due to the head of the working fluid accumulated on the check valve. A cooling device characterized by having a configuration. The cooling device according to claim 1, wherein the movable portion is movable only in a recess provided in the valve holder . The cooling device according to claim 1 or 2, wherein the check valve has a valve body installed substantially horizontally. A check valve mounting part is provided on the heat receiving part side of the return path,
The cooling device according to claim 1, wherein a plurality of check valves are stacked in the check valve mounting portion. 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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