JP5786132B2 - Electric car - Google Patents

Description

  The present invention relates to an electric vehicle having an electric motor.

  Conventionally, in this type of electric vehicle, an electric motor serving as a driving power source has been 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, natural convection causes the refrigerant to flow back and forth between the refrigerant tank and the refrigerant radiator.

  However, in such a natural convection type, the heat of the switching element can only be transmitted to the liquefied refrigerant stored in the refrigerant tank via the wall (heat transfer surface) of the refrigerant tank. The heat transfer efficiency on the hot surface could not be increased, and as a result, the cooling effect of the switching elements and the like could not be increased.

  Therefore, a cooling device that cools the inverter circuit includes a heat receiving part that absorbs heat of the inverter circuit, a heat radiating part connected to the heat receiving part via a heat radiating path, and a feedback that connects the heat radiating part and the heat receiving part. It may be configured by a path and a working fluid filled in a circulation path formed by the return path, the heat receiving section, the heat radiation path, and the heat radiation section.

  In other words, instead of the natural convection shown in Patent Document 1, the circulation type is used. However, if a compressor for circulating the working fluid is provided, the power consumption by the compressor increases, and as a result, the electric vehicle The driving distance will be shortened.

  Therefore, the cooling device includes a heat receiving portion that absorbs heat of the inverter circuit, a heat radiating portion connected to the heat receiving portion via a heat radiating path, a feedback path that connects the heat radiating portion and the heat receiving portion, and the feedback It is considered to have a configuration including a check valve disposed at a connection portion of the path to the heat receiving portion, and a working fluid filled in the circulation path formed by the return path, the heat receiving portion, the heat radiating route, and the heat radiating portion. It is done.

  In other words, the working fluid is evaporated by absorbing the heat of the inverter circuit at the heat receiving portion, the steam is supplied to the heat radiating portion by the pressure at the time of evaporation, the heat radiating is performed, and the working fluid liquefied by the heat radiation is sent to the heat receiving portion by the return path The liquid is returned and liquefied, and the check valve is opened by the hydraulic head pressure of the working fluid thus returned, and the working fluid is supplied again to the heat receiving portion.

  In this way, a compressor for circulating the working fluid becomes unnecessary, and as a result, power consumption can be suppressed and the travelable distance of the electric vehicle can be increased.

  However, even if the circulation type without using the compressor is used, the main body of the electric vehicle may be greatly tilted back and forth during its operation. Under such circumstances, the working fluid is circulated. Stops, and as a result, the inverter circuit cannot be cooled, and the driving state of the electric vehicle may become unstable.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to stabilize the driving situation of an electric vehicle.

  In order to achieve this object, the present invention includes a main body, an electric motor that drives the main body, an inverter circuit that supplies electric power to the electric motor, and a cooling device that cools the inverter circuit. The cooling device includes a heat receiving part that absorbs heat of the inverter circuit, a heat radiating part connected to the heat receiving part via a heat radiating path, a feedback path connecting the heat radiating part and the heat receiving part, A check valve disposed at a connection portion to the heat receiving portion of the path, and a working fluid filled in a circulation path formed by the return path, the heat receiving portion, the heat radiating route, and the heat radiating portion, the heat receiving portion The heat dissipating part is disposed above the heat receiving part, and the connection part of the return path to the heat receiving part is located above the floor surface of the main body. Place and return said An intermediate portion between the heat receiving portion and the heat radiating portion of the path is disposed on the floor surface of the main body below the connection portion to the heat receiving portion of the return path, and the connection portion to the heat radiating portion of the return path is The working fluid is disposed above the connection part of the return path to the heat receiving part, and the working fluid is connected from the connection part of the return path to the heat receiving part, between the heat receiving part and the heat dissipation part of the return path, and The part of the return path connected to the heat radiating part is filled up to the part of the return path above the part connected to the heat receiving part, thereby achieving the intended purpose.

  As described above, the present invention includes a main body, an electric motor that drives the main body, an inverter circuit that supplies electric power to the electric motor, and a cooling device that cools the inverter circuit. A heat receiving part that absorbs heat of the inverter circuit, a heat radiating part connected to the heat receiving part via a heat radiating path, a feedback path connecting the heat radiating part and the heat receiving part, and a heat receiving part of the feedback path A check valve disposed in the connection portion of the main body body, and a working fluid filled in a circulation path formed by the return path, the heat receiving section, the heat radiating path, and the heat radiating section. The heat dissipating part is disposed above the floor surface, the heat dissipating part is disposed above the heat receiving part, and the connection part of the return path to the heat receiving part is disposed above the floor surface of the main body body. Heat receiving part and heat radiating part The intermediate portion is disposed on the floor surface of the main body below the connection portion to the heat receiving portion of the return path, and the connection portion to the heat dissipation portion of the return path is connected to the heat receiving portion of the return path. The working fluid is disposed above the part, and the working fluid is connected from the connection part of the return path to the heat receiving part, to the intermediate part of the heat receiving part and the heat radiating part of the return path, and to the heat radiating part of the return path. Since it is a part side and is filled up to a part above the connection part to the heat receiving part of the return path, the driving situation of the electric vehicle can be stabilized.

  That is, in the electric vehicle according to the present invention, the inverter circuit is arranged on the floor so that the inverter circuit is not affected by water on the floor of the main body. It is arranged above the floor of the body.

  In such a situation, the heat dissipating part is disposed above the heat receiving part, and the connection part of the return path to the heat receiving part is disposed above the floor surface of the main body, and the return path. An intermediate portion between the heat receiving portion and the heat radiating portion is disposed on the floor surface of the body body below the connection portion to the heat receiving portion of the return path, and the connection portion to the heat radiating portion of the return path is the feedback portion. The working fluid is disposed above the connection part to the heat receiving part of the path, and the working fluid is connected to the heat receiving part from the connection part of the return path to the intermediate part of the heat receiving part and the heat radiating part of the return path, and the feedback part. The portion of the path connected to the heat radiating portion was filled up to the upper portion of the return path from the portion connected to the heat receiving portion.

  For this reason, even when the body of the electric vehicle is tilted back and forth, the working fluid must be generated by the amount of water head pressure that always opens the check valve on the connection portion side to the heat receiving portion of the return path. Can form the existing situation, and as a result, the driving situation of the electric vehicle can be stabilized.

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 Diagram showing piping configuration of the cooling device Diagram showing piping configuration 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) for driving an axle (not shown) of a main body 1 of an electric vehicle is an inverter circuit that is a power conversion device disposed in the main body 1 of the electric vehicle. 2 is connected.

  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 used for heating the main body 1 of the electric vehicle.

  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.

  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.

  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 operation, electric power is supplied to the electric motor, and the main body 1 of the electric vehicle 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 evaporates instantaneously, 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, the working fluid 12 is again supplied 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 introduction pipe 17 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 at a high speed 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 evaporated in an instant, and a large amount of substantially stationary refrigerant is received. This is a heat transfer phenomenon having a higher heat transfer rate than the case of existing above.

  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, since the inside of the circulation path is in a state where the working fluid 12 is sealed in a substantially vacuum state, the internal pressure becomes a saturated vapor pressure depending on the outside air temperature. For example, when water is used as the working fluid 12, the internal pressure is about 3 kPa (absolute pressure) when the outside air temperature is 25 ° C. Therefore, the boiling temperature of the working fluid 12 corresponding to the outside air temperature is determined, and the working fluid 12 can be easily vaporized. At this time, 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.

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

  As described above, the electric vehicle of this embodiment includes the main body 1, the electric motor that drives the main body 1, the inverter circuit 2 that supplies power to the electric motor, and the cooling device that cools the inverter circuit 2. 3 is provided.

  Further, as shown in FIG. 3, the cooling device 3 includes a heat receiving portion 4 that absorbs heat from the inverter circuit 2, a heat radiating portion 5 connected to the heat receiving portion 4 via a heat radiating path 6, A return path 7 connecting the part 5 and the heat receiving part 4, a check valve 18 disposed in a connection part of the feedback path 7 to the heat receiving part 4, the feedback path 7, the heat receiving part 4, the heat dissipation path 6, heat dissipation And a working fluid 12 filled in a circulation path formed by the section 5.

  In this basic configuration, in this embodiment, as shown in FIGS. 5 and 6, the heat receiving portion 4 is disposed above the floor surface 1 a of the main body 1, and the heat radiating portion 5 is It is arranged above the heat receiving part 4.

  Further, the connection portion of the return path 7 to the heat receiving portion 4 is disposed above the floor surface 1 a of the main body 1.

  Further, an intermediate portion between the heat receiving portion 4 and the heat radiating portion 5 of the return path 7 is disposed on the floor surface 1 a of the main body 1 below the connection portion of the return path 7 to the heat receiving portion 4.

  Furthermore, the connection part of the return path 7 to the heat radiating part 5 is disposed above the connection part of the return path 7 to the heat receiving part 4.

  The working fluid 12 is transferred from the connection portion of the return path 7 to the heat receiving portion 4 to the intermediate portion between the heat receiving portion 4 and the heat radiating portion 5 of the feedback path 7 and the heat radiating portion 5 of the feedback path 7. The return path 7 is filled up to a portion above the connection portion to the heat receiving portion 4.

  More specifically, as shown in FIG. 6, the return path 7 is piped downward from the connecting portion of the heat radiating portion 5 (A range in FIG. 6), and then the heat radiating portion 5 and the heat receiving portion of the feedback path 7. 4 is connected to the intermediate portion (B range in FIG. 6), and then piped upward from the connection portion to the heat receiving portion 4 (C range in FIG. 6). 6 (D range of FIG. 6), it is lowered toward the connection part to the heat receiving part 4 (E range of FIG. 6).

  That is, in the electric vehicle according to the present embodiment, the inverter circuit 2 is arranged on the floor surface 1a so that the inverter circuit 2 is not affected by the water on the floor surface 1a of the main body 1. The heat receiving portion 4 is also disposed above the floor surface 1a of the main body 1. The inverter circuit 2 and the heat receiving portion 4 are disposed under the seat 20 in order to effectively use the space in the vehicle. Moreover, the intermediate part (B range of FIG. 6) of the said thermal radiation part 5 and the heat receiving part 4 is also arrange | positioned on the floor surface 1a in order to utilize space effectively. Furthermore, the A range of the heat radiating unit 5 and the return path 7 is arranged in the vehicle air conditioning unit space 21.

  In such a situation, the heat dissipating part 5 is disposed above the heat receiving part 4, and the connection part of the return path 7 to the heat receiving part 4 is above the floor surface 1 a of the main body 1. The intermediate part of the heat receiving part 4 and the heat radiating part 5 of the return path 7 is arranged on the floor surface 1a of the main body 1 below the connection part to the heat receiving part 4 of the return path 7, The connection part of the return path 7 to the heat radiating part 5 is arranged above the connection part of the return path 7 to the heat receiving part 4.

  The working fluid 12 is transferred from the connection portion of the return path 7 to the heat receiving portion 4 to the intermediate portion between the heat receiving portion 4 and the heat radiating portion 5 of the feedback path 7 and the heat radiating portion 5 of the feedback path 7. The return path 7 is filled up to the upper part of the connection part to the heat receiving part 4.

  For this reason, in the initial stage of operation, the working fluid 12 is from the heat receiving part 4 side (E range of FIG. 6), (D range of FIG. 6), (C range of FIG. 6), (B range of FIG. 6), and It is in a filled state (up to the position above the D range in FIG. 6 in the A range in FIG. 6).

  For this reason, even if the main body 1 of the electric vehicle is tilted back and forth when the vehicle is traveling or stopped, the working fluid 12 is always on the side of the return path 7 connected to the heat receiving portion 4, and a check valve. The situation that exists can be formed only by the amount of water head pressure that opens 18.

  Therefore, in the heat receiving part 4, the working fluid 12 is evaporated by the heat of the inverter circuit 2, the working fluid 12 is circulated by the pressure, and as a result, the inverter circuit 2 is stably cooled, and the operation state of the electric vehicle is stabilized. It can be made.

  As described above, the present invention can stabilize the driving situation of an electric vehicle, and is expected to be widely used in future electric vehicles.

DESCRIPTION OF SYMBOLS 1 Main body body 1a Floor surface 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 Discharge port 17 Introduction pipe 18 Check valve 19 Inflow pipe 20 Seat 21 Vehicle air conditioning unit space

Claims (2)

A main body, an electric motor that drives the main body, an inverter circuit that supplies electric power to the electric motor, and a cooling device that cools the inverter circuit, the cooling device absorbs heat from the inverter circuit. A heat receiving part, a heat radiating part connected to the heat receiving part via a heat radiating path, a feedback path connecting the heat radiating part and the heat receiving part, and a check placed on a connection part of the feedback path to the heat receiving part. And a working fluid filled in a circulation path formed by the return path, the heat receiving section, the heat radiating path, and the heat radiating section, and the heat receiving section is disposed above the floor surface of the body body. The heat dissipating part is disposed above the heat receiving part, and the connection part of the return path to the heat receiving part is disposed above the floor surface of the body body, and the heat receiving part and the heat dissipating part of the return path are arranged. The middle part is the return Arranged on the floor surface of the body body below the connecting part to the heat receiving part of the path, the connecting part to the heat radiating part of the return path is arranged above the connecting part to the heat receiving part of the return path The working fluid is connected to the heat receiving portion of the feedback path, from the heat receiving portion and the heat radiating portion of the feedback path, and to the heat dissipation portion of the feedback path. An electric vehicle in which the return path is filled up to a portion above a connection portion to a heat receiving portion. The return path is piped downward from the connecting part of the heat radiating part, and then conducted to the intermediate part between the heat radiating part and the heat receiving part of the feedback path, and then piped above the connecting part to the heat receiving part. 2. The electric vehicle according to claim 1, wherein the electric vehicle is then lowered toward the connection portion to the heat receiving portion.

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