JP2014052115A - Cooling device and electric vehicle with the same - Google Patents

Abstract

An object of the present invention is to provide a cooling device capable of improving heat receiving performance and miniaturizing a heat receiving portion.
A heat receiving part, a gas-liquid heat dissipating part connected to a discharge port of the heat receiving part through a heat radiation path, and the gas liquid heat dissipating part and an inlet of the heat receiving part are connected. The heat receiving section 3 includes a heat receiving plate 12 that contacts the heat generating body and absorbs heat, and a heat receiving space 13 that covers the surface of the heat receiving plate 12 and evaporates the working fluid 11 that has flowed into the surface. The return path 10 has a check valve that opens due to the hydraulic head pressure of the working fluid 11 condensed and retained at the inlet 6 and the pressure balance between the return path 10 and the heat receiving space 13. The gas-liquid heat radiating unit 5 includes a heat transfer pipe 23 through which the working fluid 11 is circulated, and a cooling water passage 24 through which the cooling water 108 of the water-cooled cooling system 20 cooled by the cooling water 108 circulated by the pump 107 is circulated. And a configuration comprising It was.
[Selection] Figure 2

Description

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

  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. In the inverter circuit, a plurality of semiconductor switching elements represented by power transistors are used, and a large current of several tens of amperes or more flows through each element. Therefore, the semiconductor switching element generates a large amount of heat and needs to be cooled.

  For example, as in Patent Document 1, the inverter circuit disposed in the lower part is cooled by a boiling cooling device having a refrigerant radiator and a refrigerant tank at the top and bottom.

  In such a conventional cooling device, a cycle is repeated in which the refrigerant vaporized by taking the heat of the semiconductor switching element in the heat receiving part is cooled by the refrigerant radiator arranged in the upper part, liquefied and dropped again in the lower part.

  Further, in the conventional general water cooling type cooling device, as shown in FIG. 4, the semiconductor switching element 101 is in contact with the heat receiving portion 103 through the element substrate 102. A pump 107 that circulates cooling water 108 as a refrigerant is provided in the middle of a circulation path 104 that circulates and connects the heat receiving portion 103 and the heat radiating body 105. I am letting. As the cooling water 108, a mixed liquid of water and ethylene glycol, which is an antifreeze liquid, is used.

JP-A-8-126125

  In such a conventional cooling device, since the heat transfer coefficient of the heat receiving portion 103 is low, the heat receiving performance is poor, and it is not possible to cope with the high density of the semiconductor switching elements 101. As shown in FIG. As a result, there is a problem that the heat receiving unit 103 becomes large and a very heavy cooling device has to be adopted.

  Therefore, the present invention solves the above-described conventional problems, and an object of the present invention is to provide a cooling device that can improve the heat receiving performance of the heat receiving unit and reduce the size of the heat receiving unit.

  In order to achieve this object, the present invention provides a heat receiving part, a gas-liquid heat radiating part connected to the outlet of the heat receiving part via a heat radiation path, an inlet of the gas-liquid heat radiating part and the heat receiving part. The heat receiving part forms a heat receiving space that contacts the heating element and absorbs heat and covers the surface of the heat receiving plate and evaporates the working fluid that has flowed into the surface. And a check valve that opens due to a balance between the hydraulic head pressure of the working fluid condensed and retained at the inlet and the pressure balance between the return path and the heat receiving space. The gas-liquid heat radiating section includes a heat transfer pipe that circulates the working fluid, and a cooling water passage that circulates cooling water of a water-cooled cooling system that is cooled by cooling water circulated by a pump. Cooling device There, thereby it is to achieve the intended purpose.

  According to the present invention, the heat receiving portion, the gas-liquid heat radiating portion connected to the discharge port of the heat receiving portion via the heat radiating path, and the return path connecting the gas-liquid heat radiating portion and the inlet of the heat receiving portion are provided. The heat receiving portion includes a heat receiving plate that contacts the heating element to absorb heat, and a heat receiving cover that covers the surface of the heat receiving plate and forms a heat receiving space that evaporates the working fluid that has flowed into the surface. The return path includes a hydraulic head pressure of the working fluid condensed and retained at the inlet, and a check valve that opens due to a pressure balance between the inside of the return path and the heat receiving space, And the heat transfer pipe for circulating the working fluid and the cooling water passage for circulating the cooling water of the water-cooled cooling system cooled by the cooling water circulated by the pump. element The vaporization heat is taken away, vaporizes, flows through the heat dissipation path, liquefies at the gas-liquid heat dissipation part, flows through the return path, opens the check valve with the pressure of the liquid head, and flows into the heat receiving space again from the inlet. It becomes.

  At this time, the flow of the working fluid is regulated in one direction by the action of the check valve, and the cooling head with improved heat receiving performance can be obtained by the regular heat receiving and releasing cycle by the water head pressure of the liquefied working fluid. There is an effect that can be done.

  Furthermore, by having high heat receiving performance, it becomes possible to cool high-density semiconductor switching elements, and a plurality of semiconductor switching elements that have been distributed and distributed can be concentrated in a smaller area. Can be realized.

Schematic of the electric vehicle according to the first embodiment of the present invention. Schematic showing the configuration of the cooling device (A) The top view of the gas-liquid heat radiation part of the cooling device, (b) The block diagram which shows the AA cross section of the gas-liquid heat radiation part of the cooling device Schematic showing the configuration of a conventional cooling device

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

(Embodiment 1)
In the present embodiment, the configuration other than the heat receiving unit 103 of the conventional general water-cooled cooling device described in the background art is used as the water-cooled cooling system 20, and the heat-receiving performance of the heat-receiving unit of the water-cooled cooling system 20. In order to improve the efficiency, a cooling device 4 having another heat fluid performance and having a high heat receiving performance is added as a heat receiving portion. This point is the most characteristic configuration of the present invention, and this point will be described later.

  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 8 (FIG. 2). The semiconductor switching elements 8 (FIG. 2) generate heat during operation.

  For this reason, in order to cool this semiconductor switching element 8 (FIG. 2), a cooling mechanism is provided.

  This cooling mechanism has a water cooling type cooling system 20 having a configuration other than the heat receiving part 103 of the conventional water cooling type cooling apparatus described in the background art, and another working fluid system as a heat receiving part of the water cooling type cooling system 20. The cooling device 4 has a high heat receiving performance, and the gas-liquid heat radiating unit 5 connects the water-cooled cooling system 20 and the cooling device 4.

  The water-cooled cooling system 20 has a configuration other than the heat receiving unit 103 of the conventional water-cooled cooling device described in the background art, that is, a heat dissipating unit 109 including a heat dissipating body 105 and a blower 106 disposed in the front of the vehicle, and a circulation path 104. And a pump 107 provided in the middle thereof.

  The cooling device 4 as a heat receiving part of the water cooling type cooling system 20 will be described.

  Below, the cooling device 4 is demonstrated as a structure containing the gas-liquid thermal radiation part 5. FIG.

  As shown in FIG. 2, the cooling device 4 as a heat receiving unit of the water-cooled cooling system 20 dissipates the heat receiving unit 3 that absorbs heat from the semiconductor switching element 8 that is a heating element and the heat absorbed by the heat receiving unit 3. A gas-liquid heat dissipating unit 5 is provided, and a heat dissipating path 9 and a return path 10 for circulating a working fluid 11 serving as a heat medium between the heat receiving unit 3 and the gas-liquid heat dissipating unit 5 are provided.

  Further, the heat receiving section 3 includes a heat receiving plate 12 that contacts the semiconductor switching element 8 that is a heating element and absorbs heat, and a heat receiving space 13 that covers the surface of the heat receiving plate 12 and evaporates the working fluid 11 that has flowed in. A heat receiving cover 14 to be formed, an inlet 6 for flowing the liquefied working fluid 11 into the heat receiving space 13, and an outlet 7 for discharging the working fluid 11 from the heat receiving space 13 as a gas are provided.

  Further, the inlet 6 of the heat receiving space 13 is provided with a check valve 15 that is opened by the pressure of the working fluid 11 due to the water head.

  The heat radiation path 9 is connected to the discharge port 7 and the gas-liquid heat radiation part 5, and the return path 10 is connected to the inlet 6 and the gas-liquid heat radiation part 5.

  The water-cooled cooling system 20 receives the heat radiated from the cooling device 4 by the cooling water 108 circulating in the circulation path 104 of the water-cooled cooling system 20 in the gas-liquid heat radiating unit 5, and the received heat is the front surface of the vehicle. The heat is dissipated by the wind generated by the blower 106 from the heat dissipating body 105 disposed in the air.

  In addition, the heat receiving space 13, the heat radiation path 9, and the return path 10 of the cooling device 4 are hermetically sealed, and the internal pressure is made lower than the atmospheric pressure to saturate the inside. For example, when ethanol is used for the working fluid 11, the initial internal pressure is about −92 KPa at room temperature.

  In the above configuration, when the semiconductor switching element 8 of the inverter circuit 2 starts operation, electric power is supplied to an electric motor (not shown), and the electric vehicle 1 starts to move.

  At this time, a large current flows through the semiconductor switching element 8, so that at least several percent of the total power is lost and a large amount of heat is generated.

  At this time, in the cooling device 4, the liquefied working fluid 11 is accumulated on the upstream side of the check valve 15, and the check valve 15 is opened by the water head pressure of the liquefied working fluid 11, and the working fluid 11 is moved into the heat receiving space 13. To be supplied.

  Since the heat receiving plate 12 on the bottom surface of the heat receiving space 13 is heated by the heat generated from the semiconductor switching element 8 which is a heating element, a part of the working fluid 11 dropped on the heat receiving plate 12 boils and is suddenly caused by vaporization. Due to the volume expansion, a high-speed air current is generated and diffuses to the heat receiving plate 12. The high-speed air flow of the working fluid 11 entrains the remaining working fluid 11 that has not yet boiled to form a thin film layer of the working fluid 11 on the entire heat receiving plate 12, and the thin film layer of the working fluid 11 spread on the heat receiving plate 12. However, it receives the heat generated from the semiconductor switching element 8 and instantly vaporizes. By repeating this process, it is possible to efficiently vaporize the working fluid 11 and take away the heat generated from the semiconductor switching element 8 which is a heating element. As a result, the cooling performance can be improved.

  The vaporized working fluid 11 flows from the discharge port 7 of the heat receiving section 3 through the heat radiation path 9 and releases heat to the cooling water 108 circulating in the water-cooled cooling system 20 in the gas-liquid heat radiation section 5. The working fluid 11 that has released heat to the cooling water 108 liquefies, flows through the return path 10, and accumulates on the upstream side of the check valve 15 of the inlet 6 of the heat receiving unit 3. The liquefied working fluid 11 gradually increases in the return path 10, opens the check valve 15 by the pressure of the hydraulic head of the working fluid 11, and is supplied again into the heat receiving space 13.

  In this way, the working fluid 11 is repeatedly circulated in the cooling device 4 to cool the semiconductor switching element 8 that is a heating element.

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

  Since the check valve 15 opens due to the pressure balance between the hydraulic head pressure of the working fluid 11 condensed and retained upstream of the check valve 15 in the return path 10 and the heat receiving space 13, the opening time is short. Only a small amount of the working fluid 11 is supplied into the heat receiving space 13.

  Therefore, the working fluid 11 supplied into the heat receiving space 13 spreads on the heat receiving plate 12 as a thin film, and the heat receiving plate 12 is in contact with the semiconductor switching element 8. It will be heated and vaporized in an instant.

  Since the air pressure in the heat receiving space 13 is set lower than the atmospheric pressure, the working fluid 11 can be vaporized at a temperature lower than the boiling of water in the atmospheric pressure even if water is used.

  In the present embodiment, by setting the atmospheric pressure to -92 KPa and keeping the inside of the circulation path in a saturated vapor pressure state, the working fluid 11 can be easily vaporized by the temperature rise by heating from the outside. The semiconductor switching element 8 can be deprived of heat and cooled.

  That is, the heat of the semiconductor switching element 8 is taken away by the latent heat of vaporization of the working fluid 11 and the working fluid 11 is heated and vaporized instantaneously. Therefore, the accumulated working fluid 11 is simply heated and simply heated. Compared to what is boiled, the amount of heat it takes can be greatly increased. That is, the heat transfer coefficient on the surface of the heat receiving plate 12 is increased, and the heat receiving performance can be improved.

  That is, the cooling device 4 according to the present embodiment can receive a large amount of heat generated from the semiconductor switching element having a high heat density by having the high heat receiving performance, and the plurality of semiconductor switching devices arranged in a distributed manner can be received. Since it is possible to consolidate the elements into a smaller number, the heat receiving portion can be significantly downsized as a result.

  Further, when the working fluid 11 is vaporized, the pressure in the heat receiving space 13 increases. However, the working fluid 11 does not flow back to the return path 10 due to the action of the check valve 15, and the discharge port 7 is surely provided. To the heat dissipation path 9.

  That is, the heat generated from the integrated high-thermal-density semiconductor switching element 8 is effectively received by continuing the regular heat-receiving and heat-dissipating cycle by circulating the working fluid 11 in the cooling device 4 in this way. Is possible.

  Now that the basic part of the present invention has been described, the most characteristic configuration will be described below.

  As described above, the configuration other than the heat receiving unit 103 of the conventional general water-cooled cooling device described in the background art is used as the water-cooled cooling system 20, and the heat-receiving performance of the heat-receiving unit of the water-cooled cooling system 20 is improved. In order to improve, the most characteristic configuration of the present invention is that a cooling device 4 having a high heat receiving performance having another working fluid system is added as a heat receiving portion.

  As shown in FIG. 2, in the cooling device 4, heat generated from the semiconductor switching element 8 that is a heating element is transferred from the heat receiving plate 12 to the liquefied working fluid 11 in the heat receiving space 13. The working fluid 11 is instantly vaporized by the transferred heat, flows through the heat radiation path 9 from the discharge port 7, and releases heat to the water circulating in the water-cooled cooling system 20 in the gas-liquid heat radiation unit 5.

  That is, the heat received by the working fluid 11 in the heat receiving unit 3 is radiated to the cooling water 108 flowing through the water-cooled cooling system 20 in the gas-liquid heat radiating unit 5 to exchange heat.

  That is, the gas-liquid heat radiating unit 5 functions as a heat receiving unit in the water-cooled cooling system 20 and functions as a heat radiating unit in the cooling device 4 of the present invention.

  The configuration, action, and effect of the gas-liquid heat radiation unit 5 will be described with reference to FIG.

  The gas-liquid heat radiating unit 5 is a cooling water 108 of the water-cooled cooling system 20 that is cooled by the heat transfer pipe 23 (FIG. 3B) through which the working fluid 11 is circulated and the cooling water 108 circulated by the pump 107 (FIG. 2). And a cooling water channel 24 (FIG. 3B) through which the water flows.

  The heat transfer tube 23 is made of a metal such as stainless steel, copper, or aluminum. The metal used for the heat transfer tube 23 is appropriately selected depending on the type of the working fluid 11 used.

  As a result, the liquefied working fluid 11 supplied into the heat receiving space 13 takes the heat of vaporization from the semiconductor switching element 8 which is a heating element, vaporizes, and is discharged from the discharge port 7, flows through the heat radiation path 9, and flows into the gas-liquid heat radiation portion. 5, liquefies at 5, flows through the return path 10, opens the check valve 15 with the pressure of the liquid head, and flows into the heat receiving space 13 again from the inlet 6.

  At this time, the flow of the working fluid 11 is regulated in one direction by the action of the check valve 15, and a regular heat receiving and releasing cycle can be performed by the water head pressure of the liquefied working fluid 11, thereby improving the heat receiving performance. 4 can be provided.

  Furthermore, by having high heat receiving performance, it becomes possible to cool the high-density semiconductor switching elements 8, and the plurality of semiconductor switching elements 8 that are arranged in a distributed manner can be concentrated in a smaller area. No. 3 can be realized.

  Further, the gas-liquid heat radiating unit 5 includes a plurality of fins 25 that are stacked with a gap, a plurality of heat transfer tubes 23 that are vertically penetrated and joined to the fins 25, and a plurality of heat transfer tubes 23. An upstream header portion 21 joined at one end, and a downstream header portion 22 joined at the other end, and the upstream header portion 21 is connected to the heat dissipation path 9 and is connected to the downstream header portion. 22 is connected to the return path 10, and the working fluid 11 flows in the order of the heat dissipation path 9, the upstream header section 21, the heat transfer pipe 23, the downstream header section 22, and the return path 10. The outer periphery of the gas-liquid heat radiation part 5 is covered with a gas-liquid heat radiation part cover 26.

  In addition, an inlet 110 and an outlet 111 are provided at both ends of the cooling water passage 24 of the gas-liquid heat radiating unit 5. In the cooling water passage 24 of the gas-liquid heat radiating unit 5, the inlet 110 is disposed on the upstream side of the circulation path 104 of the water-cooled cooling system 20 and the outlet 111 so that the cooling water 108 flows from the heat radiation path 9 side to the return path 10 side. Are respectively connected downstream. The cooling water 108 flowing through the circulation path 104 flows into the cooling water path 24 from the inlet 110 of the cooling water path 24 of the gas-liquid heat radiation unit 5. The heat of the working fluid 11 flowing through the heat transfer pipe 23 is radiated to the cooling water 108 flowing into the cooling water passage 24 through the heat transfer pipe 23 and the fins 25. The cooling water 108 that has received heat from the working fluid 11 flows out from the outlet 111 of the cooling water passage 24 to the circulation passage 104.

  In the present embodiment, in the cooling water passage 24 of the gas-liquid heat radiating unit 5, the inlet 110 is upstream of the circulation path 104 of the water-cooled cooling system 20 so that the cooling water 108 flows from the heat radiation path 9 side to the return path 10 side. The outlet 111 is connected to the downstream side, but the cooling water 108 may flow in the opposite direction, that is, from the return path 10 side to the heat dissipation path 9 side.

  The upstream header portion 21 is disposed vertically above the downstream header portion 22.

  The fin 25 is a thin plate formed of a metal such as copper or aluminum, and the holes formed by pressing the heat transfer tubes 23 into a zigzag shape by pressing are cut into a predetermined size with a predetermined interval. It is the block body which opened and laminated.

  By alternately laminating the fins 25 and spacers (not shown), a predetermined interval is provided in the laminated fins 25. A pipe-shaped heat transfer tube 23 cut into a predetermined length is inserted into the insertion hole of the laminated fins 25. A billet (not shown), which is a tool that expands the inner diameter of the heat transfer tube from the end of the heat transfer tube 23, is inserted and expanded, whereby the heat transfer tube 23 is brought into close contact with the fins 25.

  Thereby, the high-temperature working fluid 11 vaporized by the heat generated from the semiconductor switching element 8 that is a heating element flows into the gas-liquid heat radiation part 5 from the heat radiation path 9 and is temporarily stored in the upstream header part 21, and then A heat transfer tube 23 joined to the upstream header portion 21 is circulated. At this time, the heat of the working fluid 11 is radiated from the fins 25 joined to the heat transfer tubes 23 to the cooling water flowing through the cooling water passage, and the temperature of the working fluid 11 is lowered and liquefied.

  Since the upstream header portion 21 is disposed vertically above the downstream header portion 22, the liquefied working fluid 11 is collected by dropping in the downstream header portion 22 disposed below the upstream header portion 21. The liquefied working fluid 11 does not flow backward to the upstream header portion 21 disposed above.

  Further, the working fluid 11 is temporarily stored in the downstream header portion 22 joined to the opposite side of the heat transfer tube 23 to which the upstream header portion 21 is joined, and then communicated with the downstream header portion 22. To return to the return path 10. Therefore, the working fluid 11 once stored in the upstream header portion 21 can flow relatively uniformly into the plurality of heat transfer tubes 23 joined to the upstream header portion 21. That is, since the working fluid 11 once stored in the downstream header portion 22 flows out to the return path 10, the pressure on the upstream side and the outlet side of the plurality of heat transfer tubes 23 can be made relatively uniform. As a result, the working fluid 11 can be circulated through each heat transfer tube 23 relatively uniformly.

  Thus, the heat of the working fluid 11 can be transferred to the cooling water 108 from the fins 25 having a larger area joined to the heat transfer tubes 23. As a result, it is possible to provide the cooling device 4 with further improved heat receiving performance.

  As described above, the cooling device according to the present invention includes a heat receiving portion, a gas-liquid heat radiating portion connected to the discharge port of the heat receiving portion via a heat radiating path, and the gas-liquid heat radiating portion and the inlet of the heat receiving portion. The heat receiving part is in contact with the heating element and absorbs heat, and the heat receiving part forms a heat receiving space that covers the surface of the heat receiving plate and evaporates the working fluid that has flowed into the surface. A return valve, and a check valve that opens due to a pressure balance between the hydraulic head pressure of the working fluid condensed and retained at the inlet and the heat receiving space, and the gas-liquid heat radiating unit Is provided with a heat transfer tube through which the working fluid is circulated and a cooling water passage through which the cooling water of the water-cooled cooling system cooled by the cooling water circulated by the pump, so that the liquefied working fluid in the heat receiving space is a semiconductor. Switchon It takes the heat of vaporization from the element, vaporizes it, liquefies at the heat dissipation part via the heat dissipation path, flows through the return path, and flows into the heat receiving space again from the inlet, but the working fluid acts as a check valve. The flow of air is regulated in one direction, a regular heat receiving and releasing cycle can be performed, and the heat receiving performance can be improved, so that the cooling of power conversion devices and high-speed arithmetic processing devices as electric vehicle drive devices Useful as a device.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 2 Inverter circuit 3 Heat receiving part 4 Cooling device 5 Gas-liquid heat radiating part 6 Inflow port 7 Outlet 8 Semiconductor switching element 9 Heat dissipation path 10 Return path 11 Working fluid 12 Heat receiving plate 13 Heat receiving space 14 Heat receiving cover 15 Check valve 20 Water-cooled cooling system 21 Upstream header section 22 Downstream header section 23 Heat transfer tube 24 Cooling water path 25 Fin 26 Gas-liquid heat radiation cover 101 Semiconductor switching element 102 Element substrate 103 Heat receiving section 104 Circulation path 105 Radiator 106 Blower 107 Pump 108 Cooling Water 109 Radiator 110 Inlet 111 Outlet

Claims (4)

A heat receiving part; a gas-liquid heat radiating part connected to the outlet of the heat receiving part via a heat radiating path; and a return path connecting the gas-liquid heat radiating part and the inlet of the heat receiving part. A heat receiving plate that contacts the heating element and absorbs heat; and a heat receiving cover that covers the surface of the heat receiving plate and forms a heat receiving space that evaporates the working fluid that has flowed into the surface. A check valve that opens due to a pressure balance between the water head pressure of the working fluid that has condensed and stopped at the inlet and the heat receiving space;
The gas-liquid heat radiating section includes a heat transfer pipe for circulating the working fluid, and a cooling water passage for circulating cooling water of a water-cooled cooling system cooled by cooling water circulated by a pump. . The gas-liquid heat radiating part is joined to a plurality of fins stacked with a gap, a plurality of heat transfer tubes that are vertically penetrated and joined to the fins, and one end of the plurality of heat transfer tubes. An upstream header portion and a downstream header portion joined at the other end,
The upstream header portion is connected to the heat dissipation path, the downstream header portion is connected to the return path, and the working fluid includes the heat dissipation path, the upstream header portion, the heat transfer tube, and the downstream header portion. The cooling device according to claim 1, wherein the cooling device flows in the order of the return path. The cooling apparatus according to claim 2, wherein the upstream header portion is disposed vertically above the downstream header portion. An electric vehicle comprising the cooling device according to any one of claims 1 to 3.

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