JP2013019549A - Cooling device, and electronic apparatus and electric vehicle equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device suppressing the deterioration of the cooling performance, which can supply a quantity of working fluid required for cooling, even when heat generated in a semiconductor-switching element in an inverter circuit of an electronic apparatus and an electronic vehicle is increased and the quantity of the working fluid required for cooling is increased.SOLUTION: The cooling device 3 circulates the working fluid 11 to cool it by phase change between a liquid phase and a vapor phase. The device includes a heat receiving part 4, a radiator 5, a radiation path 6, and a return path 7. A backflow valve 16 and a liquid reservoir 17 are provided on the return path 7. A large quantity of the working fluid 11 can be reserved, and thereby the cooling device 3 suppressing the deterioration of the cooling performance can be obtained which can supply the working fluid 11 to the heat receiving part 4, even when heat generated in the semiconductor-switching element 9 is increased and the quantity of the working fluid 11 required for cooling is increased.

Description

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

  Conventionally, this type of cooling device is known to be mounted on a power conversion circuit of an electronic device or 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, great heat was generated and it was necessary to cool.

  Therefore, conventionally, as in Patent Document 1, for example, the semiconductor switching element is cooled by a loop heat pipe configured by a heating unit, a cooler, and a closed loop path.

  Hereinafter, the loop heat pipe shown in Patent Document 1 will be described with reference to FIG.

  As shown in FIG. 4, the loop heat pipe includes a loop circuit that includes an ascending pipe 101 and a descending pipe 102 separately, a heat medium 103 that is a working fluid sealed in the loop circuit in a vacuum, and a part of the loop circuit. And a cooling unit 104 positioned above the loop circuit, a heating unit 105 positioned below the riser 101, and a heat medium 103 in the loop circuit interposed in the lower part of the loop circuit. And a check valve 106 for limiting the flow direction.

  Here, when heat is generated in the semiconductor switching element brought into contact with the heating unit 105, the generated heat is transmitted to the heating unit 105. Heat is applied to the heat medium 103 circulating through the heating unit 105 and vaporizes. The check valve 106 restricts the circulation direction of the heat medium 103, and the vaporized heat medium 103 rises up the rising pipe 101 and is led to the cooler 104 to be cooled. Here, the heat applied by the heating unit 105 is released. The heat medium 103 that has released the heat applied by the cooler 104 descends the downcomer 103 and circulates again to the heating unit 105 via the check valve 106.

JP 61-038396 A

  In such a conventional cooling device, when the heat generated in the semiconductor switching element increases and the amount of working fluid required for cooling exceeds the amount of working fluid stored in the downcomer, the amount required for cooling However, the working fluid cannot be supplied, and the cooling capacity is reduced.

  Therefore, the present invention solves the above-described conventional problems, and even when the heat generated in the semiconductor switching element increases and the amount of working fluid necessary for cooling increases, the amount of operation necessary for cooling is increased. It is an object of the present invention to provide a cooling device capable of supplying a fluid and suppressing a decrease in cooling capacity.

  In order to achieve this object, the present invention provides a cooling device that circulates a working fluid and cools it by a phase change between a liquid phase and a gas phase, and a heat receiving portion that transmits heat from a heating element to the working fluid. A heat dissipating part that releases heat of the working fluid; a heat dissipating path that communicates the discharge port of the heat receiving part and the heat dissipating part; and a feedback path that communicates the inlet of the heat dissipating part and the heat receiving part. The return path is provided with a backflow prevention valve, and a liquid reservoir is provided in the return path between the heat dissipating part and the backflow prevention valve, thereby achieving the intended purpose. .

  According to the cooling device of the present invention, the cooling device circulates the working fluid and cools it by the phase change between the liquid phase and the gas phase, and includes a heat receiving portion that transmits heat from the heating element to the working fluid, The heat radiation part that releases heat, a heat radiation path that communicates the discharge port of the heat receiving part and the heat radiation part, and a feedback path that communicates the heat radiation part and the inlet of the heat reception part, Comprising a backflow prevention valve, and a configuration in which a liquid reservoir is provided in the return path between the heat radiating portion and the backflow prevention valve, the liquid reservoir is compared to when no liquid reservoir is provided. Therefore, the working fluid can be accumulated by the increased content integral. As a result, even when the amount of heat generated in the heating element increases and the amount of working fluid required for cooling increases, the working fluid can be supplied to the heat receiving part, so that the reduction in cooling capacity can be suppressed. The effect that it is possible can be obtained.

Schematic of the electric vehicle according to the first embodiment of the present invention. Schematic showing a cooling device provided with a liquid reservoir Schematic showing a cooling device without a liquid reservoir Schematic showing a return path provided with a liquid reservoir ((a) Figure when the liquid reservoir is provided at a position lower than half of the straight line connecting the heat receiving part and the heat radiating part. (B) The liquid reservoir is defined as the heat receiving part. (Figure when installed at a position higher than half of the straight line connecting the heat radiation part) Schematic showing a conventional cooling device

  A cooling device according to claim 1 of the present invention is a cooling device that circulates a working fluid and cools it by a phase change between a liquid phase and a gas phase, and a heat receiving portion that transfers heat from a heating element to the working fluid; The feedback comprising a heat dissipating part for releasing the heat of the working fluid, a heat dissipating path communicating the discharge port of the heat receiving part and the heat dissipating part, and a feedback path communicating the inlet of the heat dissipating part and the heat receiving part. The path includes a backflow prevention valve, and a liquid reservoir is provided in the return path between the heat dissipating part and the backflow prevention valve.

  As a result, the working fluid can be stored by the content integral increased by providing the liquid reservoir compared to when the liquid reservoir is not provided. As a result, even when the amount of heat generated in the heating element increases and the amount of working fluid required for cooling increases, the working fluid can be supplied to the heat receiving part, so that the reduction in cooling capacity can be suppressed. There is an effect that can be done.

  Further, the cooling device according to claim 2 may be configured such that a vertical sectional area of the liquid reservoir portion with respect to the working fluid circulation direction is larger than a vertical sectional area of the return path with respect to the working fluid circulation direction.

  Thereby, compared with the case where a liquid reservoir part is not provided, the circulation amount of a working fluid can be increased by the content integral increased by having provided the liquid reservoir part. As a result, even when the amount of heat generated in the heating element increases and the amount of working fluid required for cooling increases, the working fluid can be supplied to the heat receiving part, so that the reduction in cooling capacity can be suppressed. There is an effect that can be done.

  Further, in the cooling device according to claim 3, the heat receiving portion is installed at a position lower than the heat radiating portion, and the liquid reservoir is provided at a position higher than half of a straight line connecting the heat receiving portion and the heat radiating portion. It may be configured.

  Thereby, even when a liquid reservoir is provided, the head height of the working fluid can be increased, so that the amount of working fluid supplied to the heat receiving portion can be increased. Detailed description. First, consider a case where the liquid reservoir is provided at a position lower than half of the straight line connecting the heat receiving portion and the heat radiating portion. Here, when the liquid reservoir is completely filled with the working fluid, the water head height is the height to the upper part of the liquid reservoir.

  Subsequently, considering the case where the liquid reservoir is provided at a high position while the same amount of working fluid is circulating, the liquid reservoir is filled with the working fluid partway. At this time, the head height is higher than when the liquid reservoir is provided at a low position. That is, the water head pressure increases and the pressure for circulating the working fluid to the heat receiving portion increases, so that the amount of working fluid supplied to the heat receiving portion can be increased.

  As a result, even when the amount of heat generated in the heating element increases and the amount of working fluid required for cooling increases, the working fluid can be supplied to the heat receiving part, so that the reduction in cooling capacity can be suppressed. There is an effect that can be done.

  The cooling device according to claim 4 may be configured such that the blower blows air to the outer surface of the return path.

  As a result, even when the heat applied to the working fluid in the heat receiving part cannot be completely released in the heat radiating part, the working fluid can be cooled while the working fluid circulates in the return path. The applied heat can be released.

  Compared with the working fluid that could not completely release heat, the working fluid cooled in the return path can add more heat in the heat receiving portion by the amount of heat released in the return path.

  As a result, even when the amount of heat generated in the heating element increases and the amount of working fluid required for cooling increases, the working fluid can be supplied to the heat receiving part, so that the reduction in cooling capacity can be suppressed. There is an effect that can be done.

  The cooling device according to claim 5 may be configured such that the blower blows air to an outer surface of the liquid reservoir.

  As a result, even when the heat absorbed by the working fluid in the heat receiving part cannot be completely released by the heat radiating part, the working fluid can be cooled while the working fluid is stored in the liquid reservoir, The applied heat can be released.

  Compared with the working fluid that could not completely release heat, the working fluid cooled in the liquid reservoir can add more heat in the heat receiving portion by the amount of heat released in the liquid reservoir.

  As a result, even when the amount of heat generated in the heating element increases and the amount of working fluid required for cooling increases, the working fluid can be supplied to the heat receiving part, so that the reduction in cooling capacity can be suppressed. There is an effect that can be done.

  Further, the cooling device according to claim 6 may be an electronic device including the cooling device according to any one of claims 1 to 5.

  Thereby, even when the heat generated in the heating element is increased, the electronic device is configured to include a cooling device that has an effect of supplying a working fluid to the heat receiving portion and suppressing a decrease in cooling capacity.

  As a result, even when the heat generated in the electronic device is increased and the amount of working fluid required for cooling is increased, the working fluid can be supplied to the heat receiving part, so that the reduction in cooling capacity can be suppressed. There is an effect that can be done.

  Further, the cooling device according to claim 7 may be an electric vehicle including the cooling device according to any one of claims 1 to 5.

  Accordingly, the electric vehicle has a configuration including a cooling device that has an effect of supplying the working fluid to the heat receiving portion and suppressing the decrease in the cooling capacity even when the heat generated in the heating element increases.

  As a result, even when the amount of heat generated in the electric vehicle increases and the amount of working fluid required for cooling increases, the working fluid can be supplied to the heat receiving part, so that it is possible to suppress a decrease in cooling capacity. There is an effect that can be done.

  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 the 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 (9 in FIG. 3). The semiconductor switching elements (9 in FIG. 3) generate heat during operation.

  For this reason, in order to cool this semiconductor switching element (9 in FIG. 3), a cooling device 3 is provided which cools by circulating a working fluid (11 in FIG. 3, for example, water) serving as a heat medium. .

  The cooling device 3 includes a heat receiving portion 4 that applies heat to the working fluid (11 in FIG. 3, for example, water) and a heat radiating portion 5 that releases the applied heat, and a heat medium between the heat receiving portion 4 and the heat radiating portion 5. The heat receiving part 4, the heat radiating path 6, the heat radiating part 5, the feedback path 7, and the heat receiving part 4 are provided by providing the heat radiating path 6 and the return path 7 for circulating the working fluid (11 in FIG. 3, for example, water). This constitutes a return path.

  Further, by providing the return path 7 with a check valve (16 in FIG. 3), in this return path 7, the working fluid (11 in FIG. 3, for example, water) is in a gaseous state (water vapor in the case of water) or liquid. In a state and a mixed state thereof, the heat receiving part 4, the heat radiating path 6, the heat radiating part 5, the return path 7, and the heat receiving part 4 circulate in one direction.

  Here, the heat radiating unit 5 is cooled and releases heat when the outside air is blown from the blower 8.

  The heat released from the surface of the heat radiating part 5 can also be used for heating the inside of the electric vehicle 1.

  As shown in FIG. 2, the heat receiving unit 4 forms a heat receiving plate 10 that contacts the semiconductor switching element 9 and absorbs heat, and a heat receiving space 12 that covers the surface of the heat receiving plate 10 and evaporates the working fluid 11 that has flowed in. And a heat receiving plate cover 13.

  Further, the heat receiving plate cover 13 is provided with an inlet 14 through which the working fluid 11 flows into the heat receiving space 12 from the return path 7 and an outlet 15 through which the working fluid 11 is discharged from the heat receiving space 12 into the heat radiation path 6. .

  Here, the return path 7 is provided with a backflow prevention valve 16 in the upper vicinity of the inflow port 14, and a liquid reservoir 17 is provided between the heat radiating portion 5 and the backflow prevention valve 16, so that the working fluid 11 is supplied. It can be stored.

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

  In the above configuration, when the semiconductor switching element 9 of the inverter circuit 2 starts operation, electric power is supplied to the electric motor, and the electric vehicle 1 starts to move.

  At this time, a large amount of heat is generated due to a large current flowing through the semiconductor switching element 9.

  Here, the heat generated in the semiconductor switching element 9 is transmitted to the heat receiving plate 10. The heat transmitted to the heat receiving plate 10 instantly vaporizes the liquid working fluid 11 supplied onto the heat receiving plate 10 in the heat receiving space 12 and changes it to a gas state. The working fluid in a gaseous state to which latent heat of vaporization is given circulates from the discharge port 15 to the heat radiation path 6, and is cooled and condensed by the heat radiation unit 5 to be in a liquid state, thereby releasing heat to the outside air.

  Subsequently, the liquid working fluid 11 that has released the latent heat of condensation circulates to the return path 7. The working fluid 11 is accumulated on the backflow prevention valve 16 after passing through the liquid reservoir 17. The working fluid 11 in the liquid state gradually increases in the return path 7 and the head pressure increases. On the other hand, since the working fluid 11 is not supplied in the heat receiving space 12, the working fluid 11 in the gas state gradually decreases and the pressure in the heat receiving space 12 decreases.

  The pressure upstream of the backflow prevention valve 16 (the sum of the head pressure of the working fluid 11 in the liquid state of the return path 7 and the gas pressure at the liquid surface of the working fluid 11) is the pressure downstream of the backflow prevention valve 16 ( When the pressure becomes higher than the pressure in the heat receiving space 12), the working fluid 11 passes through the check valve 16, and the working fluid 11 is again supplied onto the heat receiving plate 10 in the heat receiving space 12.

  In this way, the working fluid 11 circulates through the cooling device 3 to cool the semiconductor switching element 9.

  Here, the cooling mechanism of the heat receiving space 12 will be described with reference to FIG.

  In the heat receiving space 12, the working fluid 11 from the return path 7 is dropped as droplets on the heat receiving plate 10. The dropped working fluid 11 is diffused from the gap between the inlet 14 of the return path 7 and the heat receiving plate 10 to the outer peripheral portion. At this time, the working fluid 11 spreads as a thin film on the surface of the heat receiving plate 10, and heat from the high temperature heat receiving plate 10 is applied to vaporize in an instant.

  The pressure in the return path 7 including the heat receiving space 12 varies depending on the working fluid 11 to be used. For example, when water is used as the working fluid 11, the water in the atmospheric pressure is set by setting the pressure lower than the atmospheric pressure. It can be vaporized at a lower temperature than boiling. In the present embodiment, desired water is sealed in a return path that has been substantially reduced to a vacuum, and a saturated water vapor state corresponding to the outside air temperature is maintained. Can be vaporized.

  Thereby, the heat from the semiconductor switching element 9 is removed to the working fluid 11 as latent heat of vaporization, and efficient cooling becomes possible.

  Further, when the working fluid 11 is vaporized, the pressure in the heat receiving space 12 increases. However, the working fluid 11 does not flow back to the return path 7 due to the action of the backflow prevention valve 16, and is reliably discharged from the discharge port 15. It can be discharged 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 11 is continuously vaporized in the heat receiving space 12 to efficiently remove the heat from the semiconductor switching element 9. A great cooling effect can be realized.

  Next, the most characteristic part in this embodiment will be described.

  FIG. 2 shows the cooling device 3 provided with the liquid reservoir 17, and FIG. 3 shows the cooling device 3 without the liquid reservoir 17.

  First, the case where the semiconductor switching element 9 is cooled by the cooling device 3 not provided with the liquid reservoir 17 will be described with reference to FIG.

  As described above, the working fluid 11 in the liquid state passes through the backflow prevention valve 16, is supplied to the heat receiving space 12, and is cooled by removing the heat generated from the semiconductor switching element 9. Here, when the amount of heat generated from the semiconductor switching element 9 increases, it is necessary to supply a large amount of the working fluid 11 to the heat receiving space 12. In the case of the cooling device 3 that does not have the liquid reservoir 17 as shown in FIG. 3, the amount of the working fluid 11 in the liquid state that can be supplied to the heat receiving space 12 is the internal volume of the return path 7. If the required amount of the working fluid 11 is larger than the internal volume, the cooling capacity is lowered, and the heat generated from the semiconductor switching element 9 cannot be removed. In the worst case, the semiconductor switching element 9 is destroyed.

  Next, the case where the semiconductor switching element 9 is cooled by the cooling device 3 provided with the liquid reservoir 17 will be described with reference to FIG.

  As shown in FIG. 2, the liquid reservoir 17 is provided in the return path 7, and the internal volume increased by providing the liquid reservoir 17 compared to when the liquid reservoir 17 is not provided. Only a large amount of the working fluid 11 can be stored.

  Here, even when the amount of heat generated from the semiconductor switching element 9 increases and a large amount of the working fluid 11 needs to be supplied to the heat receiving space 12, the amount increased by providing the liquid reservoir 17. The working fluid 11 can be supplied to the heat receiving space 12.

  As a result, even when the amount of heat generated from the semiconductor switching element 9 increases and the amount of the working fluid 11 necessary for cooling increases, the working fluid 11 can be supplied to the heat receiving unit 4, so that the cooling capacity Can be suppressed.

  Further, the vertical cross-sectional area of the liquid reservoir 17 with respect to the circulation direction of the working fluid 11 indicated by the arrow in FIG.

  With such a configuration, by providing the liquid reservoir 17, it is possible to prevent the internal volume of the return path 7 from being reduced, and to reliably increase the internal volume of the return path 7.

  As a result, as described above, even when the amount of heat generated from the semiconductor switching element 9 increases and the amount of the working fluid 11 necessary for cooling increases, the working fluid 11 can be supplied to the heat receiving unit 4. Therefore, it is possible to suppress a decrease in cooling capacity.

  Further, the liquid reservoir portion 17 is provided at a position higher than half of the straight line connecting the heat receiving portion 4 and the heat radiating portion 5 so that the head height of the working fluid 11 can be increased.

  Here, it explains in full detail using FIG. FIG. 4A shows the return path 7 in which the liquid reservoir 17 is provided at a position lower than half of the straight line connecting the heat receiving part 4 and the heat radiating part 5, and FIG. 4B shows the liquid reservoir 17 half. The return path 7 provided at a higher position is shown.

  As shown in FIG. 4A, when the liquid reservoir 17 is completely filled with the working fluid 11, the water head height Ha becomes a height up to the upper portion of the liquid reservoir 17.

  Subsequently, as shown in FIG. 4 (b), when the liquid reservoir 17 is provided at a high position in the state where the same amount of the working fluid 11 as in FIG. 4 (a) is circulating, the liquid reservoir 17 is filled with the working fluid 11 halfway. At this time, the head height Hb is higher than the head height Ha when the liquid reservoir 17 is provided at a low position. That is, the head pressure is increased, and the amount of the working fluid 11 supplied to the heat receiving space 12 can be increased.

  As a result, even when the amount of heat generated from the semiconductor switching element 9 increases and the amount of the working fluid 11 necessary for cooling increases, the working fluid 11 can be supplied to the heat receiving unit 4, so that the cooling capacity Can be suppressed.

  The blower 8 is configured to blow air to the outer surface of the return path 7.

  By adopting such a configuration, even when the heat applied to the working fluid 11 in the heat receiving unit 4 cannot be completely released by the heat radiating unit 5, the working fluid 11 is circulating in the return path 7. The working fluid 11 can be cooled, and the heat applied to the working fluid 11 can be released.

  Compared with the working fluid 11 that could not completely release heat, the working fluid 11 cooled in the return path 7 can add more heat in the heat receiving portion 4 by the amount of heat released in the return path 7.

  As a result, even when the amount of heat generated from the semiconductor switching element 9 increases and the amount of the working fluid 11 necessary for cooling increases, the working fluid 11 can be supplied to the heat receiving unit 4, so that the cooling capacity Can be suppressed.

  Further, the blower 8 is configured to blow air to the outer surface of the liquid reservoir 17.

  By adopting such a configuration, even when the heat applied to the working fluid 11 in the heat receiving unit 4 cannot be completely released by the heat radiating unit 5, while the working fluid 11 is accumulated in the liquid reservoir 17. The working fluid 11 can be cooled, and the heat applied to the working fluid 11 can be released. The working fluid 11 can be supplied to the heat receiving unit 4 at a low temperature.

  Compared with the working fluid 11 that could not completely release heat, the working fluid 11 cooled in the liquid reservoir 17 can apply more heat in the heat receiving portion 4 by the amount of heat released in the liquid reservoir 17. .

  As a result, even when the amount of heat generated from the semiconductor switching element 9 increases and the amount of the working fluid 11 necessary for cooling increases, the working fluid 11 can be supplied to the heat receiving unit 4, so that the cooling capacity Can be suppressed.

  In the above embodiment, the cooling device 3 applied to the electric vehicle 1 has been described. However, the cooling device 3 can also be applied to an electronic device.

  The cooling device according to the present invention can supply the working fluid to the heat receiving portion even when the amount of heat generated from the semiconductor switching element is large and the amount of the working fluid necessary for cooling is large. It is also useful for cooling semiconductor switching elements in inverter circuits of electric vehicles.

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 Blower 9 Semiconductor switching element 10 Heat receiving plate 11 Working fluid 12 Heat receiving space 13 Heat receiving plate cover 14 Inlet 15 Outlet 16 Backflow prevention valve 17 Liquid reservoir

Claims (7)

  A cooling device that circulates a working fluid and cools it by a phase change between a liquid phase and a gas phase, a heat receiving portion that transfers heat from a heating element to the working fluid, a heat radiating portion that releases heat of the working fluid, and A heat radiation path that communicates the discharge port of the heat receiving part and the heat radiation part, and a feedback path that communicates the heat radiation part and the inlet of the heat reception part, the feedback path includes a backflow prevention valve, and the heat radiation A cooling device, wherein a liquid reservoir is provided in the return path between the valve and the check valve.   2. The cooling device according to claim 1, wherein a vertical sectional area of the liquid reservoir with respect to the working fluid circulation direction is larger than a vertical sectional area of the return path with respect to the working fluid circulation direction.   The backflow prevention valve is configured to circulate the working fluid by a pressure difference between the front and rear, the heat receiving portion is installed at a position lower than the heat radiating portion, and the liquid reservoir portion is a straight line connecting the heat receiving portion and the heat radiating portion. The cooling device according to claim 1, wherein the cooling device is provided at a position higher than a half of the cooling device.   The cooling device according to claim 1, further comprising a blower that blows air to the heat radiating unit, wherein the blower blows air to an outer surface of the return path.   The cooling device according to claim 4, wherein the blower blows air to an outer surface of the liquid reservoir.   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 5.

Images