Temperature control device for battery unit for electric vehicle

Abstract

To efficiently cool an electric vehicle battery unit.SOLUTION: A temperature control device of an electric vehicle battery unit comprises: at least one battery unit 2 which is positioned at an underfloor 11 and outputs electric power for traveling of an electric vehicle 1; a refrigerant system 3 cooling the battery unit which includes a pipe 32 where refrigerant receiving heat from the battery unit flows and a heat exchanger (radiator 31) in which the pipe is connected to the heat exchanger and heat release of the refrigerant is performed; an air passage 4 which opens to both of a front side and a rear side of the electric vehicle and makes air flow at least during traveling of the electric vehicle; and a heat conduction material 5 which is arranged between the pipe and the air passage and transmits heat from the refrigerant to the air in the air passage.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The technology disclosed herein relates to a temperature control device for a battery unit for an electric vehicle. [Background technology]

[0002] Patent Document 1 describes a cooling structure for a vehicle power supply device. The power supply device is a battery mounted on an electric vehicle. The battery is disposed between a floor panel and an undercover. An air duct is also disposed between the floor panel and the undercover. The air duct opens toward the front of the vehicle and toward the rear of the vehicle. Wind generated when the vehicle is traveling flows through the air duct. The wind flowing through the air duct cools the battery.

[0003] A cooling device for a vehicle battery is described in Patent Document 2. The cooling device cools the battery by circulating coolant between the battery and a radiator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-35323 A [Patent Document 2] JP 2013-107420 A Summary of the Invention [Problem to be solved by the invention]

[0005] In order to suppress temperature deterioration of the battery unit of an electric vehicle, the battery unit must be cooled efficiently. Unfortunately, conventional cooling devices are unable to efficiently cool the battery unit.

[0006] The technology disclosed herein efficiently cools a battery unit for an electric vehicle. [Means for solving the problem]

[0007] Specifically, the technology disclosed herein relates to a temperature control device for a battery unit for an electric vehicle. At least one battery unit that is located under a floor of an electric vehicle and outputs electricity for driving the electric vehicle; a refrigerant system including a pipe through which a refrigerant that has received heat from the battery unit flows and a heat exchanger to which the pipe is connected and which dissipates heat from the refrigerant, the refrigerant circulating between the battery unit and the heat exchanger to cool the battery unit; an air passage that opens to a front and a rear of the electric vehicle and through which air flows at least while the electric vehicle is traveling; and a heat conductive material interposed between the pipe and the air passage and configured to transfer heat from the refrigerant to the air in the air passage.

[0008] This temperature control device cools the battery unit by utilizing both the heat exchanger and the air passage. Specifically, the refrigerant system circulates a refrigerant between the battery unit and the heat exchanger. The refrigerant receives heat from the battery unit and dissipates the heat in the heat exchanger. The heat exchanger may be, for example, a radiator. In addition, when the refrigerant is an air conditioning refrigerant, the condenser serves as the heat exchanger.

[0009] When the electric vehicle is running, air (i.e., the wind generated by running) flows through the air passage. A thermally conductive material is interposed between the refrigerant pipe and the air passage. Heat from the refrigerant is transferred through the pipe and the thermally conductive material, and is released to the air flowing through the air passage. The thermally conductive material promotes the transfer of heat from the refrigerant to the air. The refrigerant that has received heat from the battery unit is cooled by the air passage and also by the heat exchanger.

[0010] Therefore, in the temperature control device, the refrigerant that has received heat from the battery unit is cooled by the air flowing through the air passage while flowing through the pipe toward the heat exchanger, and is also cooled in the heat exchanger. The temperature control device can efficiently cool a battery unit for an electric vehicle. The temperature control device can prevent the battery unit from overheating, and therefore can prevent temperature deterioration of the battery unit.

[0011] the air passage has a first on-off valve that opens and closes an inlet of the air passage, The first on-off valve may close the inlet of the air passage when the temperature of the battery unit is equal to or lower than a first temperature.

[0012] When the first on-off valve closes the inlet of the air passage, air does not flow through the air passage. The refrigerant is not cooled by the air, or is cooled poorly. When the first on-off valve closes the inlet of the air passage during a cold state, when the temperature of the battery unit is below the first temperature, this is favorable for raising the temperature of the battery unit.

[0013] When the first on-off valve closes the inlet of the air passage, the refrigerant system may stop circulating the refrigerant. In this case, the refrigerant system also does not cool the battery unit, which promotes a rise in temperature of the battery unit.

[0014] the battery unit includes a first battery unit and a second battery unit located rearward of the first battery unit with respect to the electric vehicle; the thermally conductive material is interposed between the pipe and the air passage at a position corresponding to the first battery unit and a position corresponding to the second battery unit, The air passage is a state in which air flows through the first battery unit and then the second battery unit; a state in which air flows to the second battery unit, bypassing the first battery unit; It may also be said that the switch is switched to.

[0015] When multiple battery units are lined up in the longitudinal direction of an electric vehicle, the battery units located relatively closer to the front are more likely to be cooled by the wind as the vehicle travels. Battery units located relatively further back are less likely to be cooled by the wind as the vehicle travels, and may become hotter. When there is variation in temperature among multiple battery units lined up in the longitudinal direction, it is more efficient to selectively cool one of the battery units rather than cooling the multiple battery units evenly.

[0016] When the air passage is in a state where air flows through the first battery unit and then the second battery unit, the first battery unit and the second battery unit are cooled equally or approximately equally by the air. When the air passage is in a state where air flows to the second battery unit, bypassing the first battery unit, the second battery unit is preferentially cooled by the air. By switching the air passage between the two states, the temperature control device can efficiently cool multiple battery units.

[0017] In the temperature control device for an electric vehicle battery unit, the heat exchanger is located in a power unit room in front of the battery unit, and has a fan that receives power and generates an air flow; the air passage communicates with the power unit room through an air vent and has a second opening / closing valve that opens and closes the air vent, the second on-off valve opens the vent hole while the vehicle is stopped and the battery unit is being charged, The fan is driven while the vehicle is stopped and the battery unit is being charged. do.

[0018] When the electric vehicle is stopped, no wind is generated due to the vehicle's running, and the wind cannot be used to cool the battery unit. On the other hand, when the battery unit is being charged while the electric vehicle is stopped, it may be desirable to cool the battery unit.

[0019] The temperature control device uses the fan of the heat exchanger to generate an air flow while the electric vehicle is stopped and the battery unit is being charged. Specifically, the air passage and the power unit room are in communication through an air vent, and when the fan in the power unit room is driven with the second on-off valve opening the air vent, an air flow is generated in the air passage. In this state, the refrigerant system circulates the refrigerant, so that the refrigerant that has received heat from the battery unit is cooled by the air flow flowing in the air passage and is also cooled in the heat exchanger. The battery unit being charged is efficiently cooled even when the vehicle is stopped.

[0020] The fan generates an air flow from the front to the rear of the electric vehicle while the electric vehicle is traveling, The fan may generate an air flow from the rear to the front of the electric vehicle while the electric vehicle is stopped and the battery unit is being charged.

[0021] When the fan is driven to generate an air flow from the rear to the front of the electric vehicle, the air introduced from the rear opening of the air passage flows through the air passage. The temperature of the air flowing through the air passage becomes relatively low, which improves the cooling efficiency of the battery unit.

[0022] A temperature control device for an electric vehicle battery unit different from the above, the battery unit includes a front battery unit and a rear battery unit located rearward of the front battery unit with respect to the electric vehicle; the thermally conductive material is interposed between the pipe and the air passage at a position corresponding to the front battery unit and a position corresponding to the rear battery unit, the air passage has a partition wall that divides the inside of the air passage into a first passage in contact with the thermally conductive material and a second passage away from the thermally conductive material; the partition has a communication portion that communicates between the first passage and the second passage, the communication portion being located intermediate between a position corresponding to the front battery unit and a position corresponding to the rear battery unit; The air passage is a state in which air flows through the first passage at both a position corresponding to the front battery unit and a position corresponding to the rear battery unit; a state in which air flows through the second passage at a position corresponding to the front battery unit, passes through the communication portion, and then flows through the first passage at a position corresponding to the rear battery unit; Switched to do.

[0023] By having a communication portion in the partition wall that separates the inside of the air passage into the first passage and the second passage, the air flow in the air passage can be redirected from the first passage to the second passage, or from the second passage to the first passage.

[0024] In a state in which air flows through the first passages at both the position corresponding to the front battery unit and the position corresponding to the rear battery unit, both the front battery unit and the rear battery unit are cooled evenly or approximately evenly.

[0025] When the air flows through the second passage at a position corresponding to the front battery unit, passes through the communication portion, and flows through the first passage at a position corresponding to the rear battery unit, the rear battery unit is cooled preferentially.

[0026] The air passage further comprises: The air may first flow through the first passage at a position corresponding to the front battery unit, and then pass through the communication portion, and switch to flow through the second passage at a position corresponding to the rear battery unit.

[0027] In this state, the front battery unit is cooled preferentially.

[0028] The air passage further comprises: The air may flow through the first passage and the second passage at a position corresponding to the front battery unit, and then pass through the communication portion, switching to a state in which the air flows only through the first passage at a position corresponding to the rear battery unit.

[0029] In this state, the flow rate of air flowing through the first passage increases, so both the front and rear battery units can be further cooled, or when the electric vehicle speed is low, both the front and rear battery units can be efficiently cooled. Effect of the Invention

[0030] As described above, the temperature control device for an electric vehicle battery unit can efficiently cool the battery unit. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 shows an electric vehicle equipped with a temperature control device for a battery unit. [Diagram 2] FIG. 2 conceptually illustrates an exemplary battery unit temperature control device. [Diagram 3] FIG. 3 shows a block diagram of a temperature control device for a battery unit. [Figure 4] FIG. 4 shows a part of the control flow of the temperature control device. [Diagram 5] FIG. 5 shows a part of the control flow of the temperature control device. [Figure 6] FIG. 6 shows a state in which the first battery unit is cooled preferentially. [Figure 7] FIG. 7 shows a state in which the second battery unit is given cooling priority. [Figure 8] FIG. 8 shows a state in which the first battery unit and the second battery unit are evenly cooled. [Figure 9] FIG. 9 shows a state in which the first and second battery units are further cooled. [Figure 10] FIG. 10 shows a state in which the first battery unit and the second battery unit are being cooled while the electric vehicle is stopped. [Figure 11] FIG. 11 shows a state in which the first battery unit and the second battery unit are further cooled while the electric vehicle is stopped. [Figure 12] FIG. 12 conceptually illustrates a modified example of the temperature control device for the battery unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a temperature control device for a battery unit for an electric vehicle will be described with reference to the drawings. The temperature control device described here is merely an example.

[0033] (Overall structure of electric vehicle) The temperature control device for the battery unit is mounted on an electric vehicle 1. Fig. 1 conceptually illustrates the configuration of the electric vehicle 1. In the following description, "front" refers to the "front" of the electric vehicle 1, i.e., the left side of the paper in Fig. 1, and "rear" refers to the "rear" of the electric vehicle 1, i.e., the right side of the paper in Fig. 1.

[0034] The electric vehicle 1 is a hybrid vehicle (Hybrid Electric Vehicle or Plug-in Hybrid Electric Vehicle) or an electric vehicle (Battery Electric Vehicle). The electric vehicle 1 is equipped with an electric motor. The electric motor generates driving force for running the electric vehicle. The electric motor is installed, for example, in a power unit room 12 of the electric vehicle 1. In the electric vehicle 1 shown in the figure, the power unit room 12 is located at the front of the electric vehicle 1.

[0035] The electric vehicle 1 is equipped with a battery unit 2. The battery unit 2 supplies electricity to the electric motor. The battery unit 2 is located under a floor 11 of the electric vehicle 1. The battery unit 2 is also located behind a power unit room 12.

[0036] The electric vehicle 1 in the illustrated example has a first battery unit 21 and a second battery unit 22 as the battery units 2. The first battery unit 21 and the second battery unit 22 are aligned in the front-to-rear direction. More specifically, the second battery unit 22 is located behind the first battery unit 21. The first battery unit 21 is a front battery unit, and the second battery unit 22 is a rear battery unit. The number of battery units is not limited to two, and may be three or more.

[0037] The electric vehicle 1 is equipped with a refrigerant system 3. The refrigerant system 3 has a radiator 31 that dissipates heat from the refrigerant, and a pipe 32 through which the refrigerant flows. The radiator 31 is an example of a heat exchanger. The pipe 32 connects between the battery unit 2 and the radiator 31. The pipe 32 constitutes an outward path and a return path. The refrigerant receives heat from the battery unit 2.

[0038] The pipe 32 is connected to a radiator 31. The radiator 31 is located at the front of the power unit room 12. The radiator 31 is a heat exchanger that exchanges heat between a refrigerant and air. The radiator 31 releases heat from the refrigerant mainly by utilizing the wind generated when the electric vehicle 1 is traveling. The refrigerant system 3 cools the battery unit 2 by circulating the refrigerant between the battery unit 2 and the radiator 31.

[0039] The heat exchanger is not limited to the radiator 31. When the refrigerant is an air-conditioning refrigerant, a condenser serves as the heat exchanger.

[0040] The electric vehicle 1 also has an air passage 4. The air passage 4 is located under the electric vehicle 1. The air passage 4 extends in the front-to-rear direction. The air passage 4 opens to the front of the electric vehicle 1 and also opens to the rear of the electric vehicle 1. While the electric vehicle 1 is traveling, wind generated during traveling is introduced into the air passage 4 from the front, flows through the air passage 4, and then is discharged from the rear. The temperature control device for the battery unit efficiently cools the battery unit 2 by combining the refrigerant system 3 with the air passage 4, through which the wind flows.

[0041] (Detailed structure of temperature control device) 2 shows a detailed structure of the temperature control device. The temperature control device includes a battery unit 2 to be cooled, the refrigerant system 3, and the air passage 4.

[0042] As described above, the battery unit 2 has the first battery unit 21 and the second battery unit 22. Each of the first battery unit 21 and the second battery unit 22 is configured with a plurality of cells housed in a case. The cells are secondary batteries that can be charged and discharged. The plurality of cells are lined up inside the case. The plurality of cells are electrically connected by bus bars.

[0043] The pipes 32 of the refrigerant system 3 include a first pipe 321 and a second pipe 322. The first pipe 321 is an outward or return path of the path through which the refrigerant flows in the refrigerant system 3, and the second pipe 322 is a return or outward path. The pipes 32 are also disposed between the cells in each of the first battery unit 21 and the second battery unit 22. The pipes 32 disposed between the cells connect the first pipes 321 and the second pipes 322 to each other. In the example of FIG. 2, the pipes 32 disposed between the cells extend in the vertical direction, but in a state in which the electric vehicle 1 is mounted, the pipes 32 disposed between the cells are not necessarily disposed to extend in the vertical direction. The pipes 32 disposed between the cells may be disposed to extend in the vehicle width direction or in the vehicle front-rear direction.

[0044] The refrigerant system 3 has a pump 33. The pump 33 is disposed midway through the pipe 32. In the example of Fig. 2, the pump 33 is disposed in the first pipe 321 inside the battery unit 2, but the location of the pump 33 is not limited to this location. The pump 33 can be disposed in any appropriate location.

[0045] The radiator 31 has a fan 34. When the fan 34 is driven, an air flow passing through the radiator 31 is generated. The air flow passing through the radiator 31 promotes the heat dissipation of the refrigerant in the radiator 31. A damper 35 is located in front of the radiator 31. The damper 35 is located in the grill of the electric vehicle 1. The damper 35 switches between a state in which the grill is closed as shown in FIG. 2 and a state in which the grill is open as shown in FIG. 9. When the damper 35 closes the grill, the air flow passing through the radiator 31 is suppressed even when the electric vehicle 1 is running, so that the heat dissipation of the refrigerant is also suppressed. On the other hand, when the damper 35 closes the grill, the running resistance of the electric vehicle 1 is reduced. The reduction in running resistance improves the electric cost or fuel efficiency of the electric vehicle 1. When the damper 35 opens the grill, the air flow passing through the radiator 31 is promoted, so that the heat dissipation of the refrigerant is also promoted.

[0046] When the pump 33 is driven, the refrigerant flows through the pipe 32. The refrigerant circulates between the battery unit 2 and the radiator 31 by flowing through the pipe 32. The refrigerant receives heat from each of the first cell unit 21 and the second cell unit 22, and dissipates heat in the radiator 31. In this way, the refrigerant system 3 cools the first cell unit 21 and the second cell unit 22. There is no restriction on the flow direction of the refrigerant in Figure 2. The refrigerant may flow in a clockwise direction or a counterclockwise direction in Figure 2.

[0047] The temperature control device of the battery unit 2 includes a heater 61. The heater 61 is disposed so as to be in contact with the first battery unit 21 and also so as to be in contact with the second battery unit 22. The heater 61 warms up the first battery unit 21 and the second battery unit 22 when the first battery unit 21 and the second battery unit 22 are cold. The temperatures of the first battery unit 21 and the second battery unit 22 rise. The heater 61 can warm up the first battery unit 21 and the second battery unit 22 individually.

[0048] The air passage 4 is located below the battery unit 2. A thermally conductive material 5 is interposed between the air passage 4 and the second pipe 322. More specifically, the thermally conductive material 5 forms a part of the air passage 4. The thermally conductive material 5 extends in the front-rear direction so as to span both the first battery unit 21 and the second battery unit 22. The thermally conductive material 5 promotes heat transfer from the refrigerant flowing inside the second pipe 322 to the air flowing through the air passage 4. The presence of the thermally conductive material 5 makes it possible to cool the refrigerant using the air flowing through the air passage 4.

[0049] A partition wall is provided in the air passage 4. The partition wall divides the air passage 4 into first passages 441, 451 that contact the thermally conductive material 5 and second passages 442, 452 that are distant from the thermally conductive material 5. The partition wall has a communication portion 433 at an intermediate position between a position corresponding to the first cell unit 21 and a position corresponding to the second cell unit 22. The communication portion 433 communicates between the first passages 441, 451 and the second passages 442, 452. The communication portion 433 divides the partition wall into a front partition wall 431 and a rear partition wall 432. In addition, the first passage is divided into a first front passage 441 corresponding to the front partition 431 and a first rear passage 451 corresponding to the rear partition 432, and the second passage is divided into a second front passage 442 corresponding to the front partition 431 and a second rear passage 452 corresponding to the rear partition 432.

[0050] The air passage 4 has a first on-off valve that opens and closes the inlet 41. The first on-off valve includes an F1 valve 51 and an F2 valve 52. The F1 valve 51 opens and closes the inlet of the first front passage 441. The F2 valve 52 opens and closes the inlet of the second front passage 442.

[0051] An R1 valve 53 and an R2 valve 54 are disposed inside the air passage 4. The R1 valve 53 is located at the entrance of the first rear passage 451 and opens and closes the entrance. The R2 valve 54 is located at the entrance of the second rear passage 452 and opens and closes the entrance.

[0052] Although details will be described later, the air flow path is switched by switching between opening and closing of the F1 valve 51, the F2 valve 52, the R1 valve 53, and the R2 valve .

[0053] The air passage 4 communicates with the power unit room 12 through the ventilation opening 46. The ventilation opening 46 is located at the middle position of the first front passage 441 in the front-rear direction. A C1 valve 55 is located in the ventilation opening 46. The C1 valve 55 opens and closes the ventilation opening 46. When the C1 valve 55 is open, the power unit room 12 and the first front passage 441 communicate with each other.

[0054] As shown in FIG. 3, the electric vehicle 1 has a control unit 7. The control unit 7 adjusts the temperatures of the first battery unit 21 and the second battery unit 22. The first temperature sensor 71 measures the temperature of the first battery unit 21. The first temperature sensor 71 is electrically connected to the control unit 7. The first temperature sensor 71 outputs a measurement signal related to the temperature of the first battery unit 21 to the control unit 7. The second temperature sensor 72 measures the temperature of the second battery unit 22. The second temperature sensor 72 is electrically connected to the control unit 7. The second temperature sensor 72 outputs a measurement signal related to the temperature of the second battery unit 22 to the control unit 7.

[0055] The vehicle speed sensor 73 measures the vehicle speed of the electric vehicle 1. The vehicle speed sensor 73 is electrically connected to the control unit 7. The vehicle speed sensor 73 outputs a measurement signal related to the vehicle speed to the control unit 7. The control unit 7 determines whether the electric vehicle 1 is stopped or traveling based on the measurement signal of the vehicle speed sensor 73. When the electric vehicle 1 is traveling, the control unit 7 also determines whether the electric vehicle 1 is traveling at a high speed higher than a predetermined speed or at a low speed equal to or lower than the predetermined speed.

[0056] The control unit 7 is also electrically connected to the heater 61, the pump 33, the fan 34, the damper 35, the F1 valve 51, the F2 valve 52, the R1 valve 53, the R2 valve 54, and the C1 valve 55. The control unit 7 outputs control signals to each of these devices. Each device operates upon receiving a control signal from the control unit 7.

[0057] (Temperature control by temperature control device) Next, the temperature control of the battery unit 2 by the temperature control device will be described in detail with reference to the flowcharts of FIG. 4 and FIG.

[0058] First, in step S41 after the start of the flow in FIG. 4, the control unit 7 reads the temperature Tbf of the first battery unit 21 based on the measurement signal of the first temperature sensor 71 and the temperature Tbr of the second battery unit 22 based on the measurement signal of the second temperature sensor 72. In the following step S42, the control unit 7 judges whether Tbf and Tbr exceed a first temperature T1. The first temperature T1 is a reference temperature for the battery unit 2 being cold. The first temperature T1 is predetermined and stored in the control unit 7. If the judgment in step S42 is YES, in other words, if the battery unit 2 is not cold, the process proceeds to step S43. If the judgment in step S42 is NO, in other words, if the battery unit 2 is cold, the process proceeds to step S44.

[0059] In step S44, the control unit 7 turns on the heater 61 and turns off the pump 33. With the pump 33 turned off, the refrigerant system 3 does not substantially function. The damper 35 is also closed. The control unit 7 also closes all the valves 51, 52, 53, 54, and 55. Even if the electric vehicle 1 is running, the running wind does not flow through the air passage 4. Figure 2 shows the state of the temperature control device in step S44. After step S44, the process returns to step S41.

[0060] In step S43, the control unit 7 turns off the heater 61 and turns on the pump 33. In the refrigerant system 3, the refrigerant circulates.

[0061] In the next step S45, the control unit 7 judges whether Tbf or Tbr exceeds a second temperature T2. The second temperature T2 is a reference temperature for indicating that active cooling of the battery unit 2 is necessary, and T2>T1. The second temperature T2 is predetermined and stored in the control unit 7.

[0062] If the determination in step S45 is NO, in other words, if active cooling of the battery unit 2 is not required, the process returns to step S41. In this case, only the refrigerant system 3 cools the battery unit 2. In this case, the damper 35 may be closed or open. Also, when the damper 35 is open, the fan 34 may be ON or OFF.

[0063] If the determination in step S45 is YES, in other words, if active cooling of the battery unit 2 is required, the process proceeds to step S46.

[0064] In step S46, the control unit 7 determines whether the electric vehicle 1 is parked or charging. Note that "parked" means that the electric vehicle 1 is parked but not charging, and "charging" means that the electric vehicle 1 is parked and charging. If the determination in step S46 is YES, the process proceeds to step S47. If the determination in step S46 is NO, that is, if the electric vehicle 1 is traveling and discharging, the process proceeds to step S411 in FIG. 5.

[0065] In step S411, the control unit 7 determines whether both Tbf and Tbr exceed the second temperature T2. If the determination in step S411 is YES, in other words, if the temperatures of both the first battery unit 21 and the second battery unit 22 are high, the process proceeds to step S412, and if the determination in step S411 is NO, in other words, if the temperature of either the first battery unit 21 or the second battery unit 22 is high, the process proceeds to step S414.

[0066] In step S414, the control unit 7 determines whether Tbf exceeds the second temperature T2. If the determination in step S414 is YES, in other words, if the temperature of the first battery unit 21 is high, the process proceeds to step S415, and if the determination in step S414 is NO, in other words, if the temperature of the second battery unit 22 is high, the process proceeds to step S416.

[0067] In step S415, the control unit 7 cools the first cell unit 21 preferentially among the first cell unit 21 and the second cell unit 22. Specifically, the control unit 7 opens the F1 valve 51 and the R2 valve 54, and closes the F2 valve 52, the R1 valve 53, and the C1 valve 55. As a result, as shown by the arrows in FIG. 6, the air flows through the first front passage 441 in the air passage 4, then flows through the communication part 433, the second rear passage 452, and exits from the outlet 42 of the air passage 4. In this state, heat is transferred from the refrigerant flowing through the second pipe 322 to the air near the first cell unit 21, thereby cooling the first cell unit 21. On the other hand, the air does not flow through the first rear passage 451, so that the cooling of the second cell unit 22 is suppressed. In this way, the first cell unit 21 is preferentially cooled using the refrigerant system 3 and the air passage 4.

[0068] In step S416, the control unit 7 preferentially cools the second cell unit 22 out of the first cell unit 21 and the second cell unit 22. Specifically, the control unit 7 opens the F2 valve 52 and the R1 valve 53, and closes the F1 valve 51, the R2 valve 54, and the C1 valve 55. As a result, as shown by the arrows in FIG. 7, the air flows through the second front passage 442 in the air passage 4, then flows through the communication part 433, the first rear passage 451, and exits from the outlet 42 of the air passage 4. In this state, heat is transferred from the refrigerant flowing through the second pipe 322 to the air near the second cell unit 22, thereby cooling the second cell unit 22. On the other hand, the air does not flow through the first front passage 441, so that the cooling of the first cell unit 21 is suppressed. In this way, the second cell unit 22 is preferentially cooled using the refrigerant system 3 and the air passage 4.

[0069] In step S412, the control unit 7 judges whether Tbf and Tbr exceed a fourth temperature T4. The fourth temperature T4 is a reference temperature indicating that the temperature of the battery unit 2 is too high and active cooling of the battery unit 2 is required, and T4>T2. The fourth temperature T4 is predetermined and stored in the control unit 7.

[0070] If the determination in step S412 is YES, in other words, if active cooling of the high-temperature battery unit 2 is required, the process proceeds to step S413, or if the determination in step S412 is NO, the process proceeds to step S417.

[0071] In step S417, the control unit 7 judges whether Tbf and Tbr exceed a third temperature T3. The third temperature T3 is a temperature lower than T4 and higher than T2 (T4>T3>T2). The third temperature T3 is predetermined and stored in the control unit 7.

[0072] If the determination in step S417 is YES, the process proceeds to step S419, and if the determination is NO, the process proceeds to step S418.

[0073] In step S418, the control unit 7 opens the F1 valve 51 and the R1 valve 53, and closes the F2 valve 52, the R2 valve 54, and the C1 valve 55. As a result, as shown by the arrows in Fig. 8, the air flows through the first front passage 441 in the air passage 4, then flows through the first rear passage 451, and exits from the outlet 42 of the air passage 4. Heat is transferred from the refrigerant flowing through the second pipe 322 to the air near each of the first cell unit 21 and the second cell unit 22, making it possible to efficiently cool both the first cell unit 21 and the second cell unit 22.

[0074] In step S419, the control unit 7 opens the F1 valve 51, the F2 valve 52, and the R1 valve 53, and closes the R2 valve 54 and the C1 valve 55. As a result, as shown by the arrows in FIG. 9, the air flows through the first front passage 441 and the second front passage 442 in the air passage 4, joins with the communication part 433, flows through the first rear passage 451, and exits from the outlet 42 of the air passage 4. Compared to FIG. 8, the flow rate of air flowing through the air passage 4 is increased, so that both the first battery unit 21 and the second battery unit 22 can be further cooled. Furthermore, even when the vehicle speed of the electric vehicle 1 is low, both the first battery unit 21 and the second battery unit 22 can be efficiently cooled. In addition, in step S419, the control unit 7 may open the damper 35 (see FIG. 9). When the damper 35 is opened, the refrigerant system 3 can promote heat dissipation from the refrigerant, and therefore can cool both the first cell unit 21 and the second cell unit 22 more efficiently.

[0075] In step S413, the control unit 7 opens the F1 valve 51, the F2 valve 52, the R1 valve 53, the R2 valve 54, and the C1 valve 55. This causes air to flow through the first front passage 441, the second front passage 442, the first rear passage 451, and the second rear passage 452 in the air passage 4. Since the flow rate of air flowing through the air passage 4 increases, it becomes possible to further cool both the first battery unit 21 and the second battery unit 22. Note that, in step S413 as well, the control unit 7 may open the damper 35. This promotes the flow of air from the power unit room 12 to the air passage 4 through the communication part 433, so that the flow rate of air flowing through the air passage 4 further increases.

[0076] Returning to FIG. 4, in step S47, the control unit 7 drives the fan 34 of the radiator 31 in the reverse direction. In addition, the control unit 7 opens the damper 35. This generates an air flow even when the electric vehicle 1 is stopped. The refrigerant system 3 can efficiently dissipate heat from the refrigerant.

[0077] In the next step S48, the control unit 7 judges whether Tbf or Tbr exceeds the third temperature T3 (T4>T3>T2). If the judgment in step S48 is YES, the process proceeds to step S410, and if the judgment is NO, the process proceeds to step S49.

[0078] In step S49, the control unit 7 opens the R1 valve 53 and the C1 valve 55, and closes the F1 valve 51, the F2 valve 52, and the R2 valve 54. As a result, as shown by the arrows in Fig. 10, air flows from the outlet 42 in the air passage 4 toward the first rear passage 451 and the first front passage 441, and flows through the vent 46 to the power unit compartment 12. Even when the electric vehicle 1 is stopped and no wind is generated while the vehicle is running, air flows through the air passage 4, and heat is transferred from the refrigerant flowing through the second pipe 322 to the air near the first battery unit 21 and the second battery unit 22, thereby efficiently cooling each of the first battery unit 21 and the second battery unit 22.

[0079] On the other hand, in step S410, the control unit opens the R1 valve 53, the R2 valve 54, and the C1 valve 55, and closes the F1 valve 51 and the F2 valve 52. As a result, as shown by the arrows in Fig. 11, the air flows through the first rear passage 451 and the second rear passage 452 in the air passage 4, joins with the communication part 433, flows through the first front passage 441, and flows from the ventilation opening 46 to the power unit room 12. Compared to Fig. 10, the flow rate of air flowing through the air passage 4 is increased, so that both the first battery unit 21 and the second battery unit 22 can be further cooled. For example, during quick charging, the temperature of both the first battery unit 21 and the second battery unit 22 can be prevented from rising excessively.

[0080] As described above, in the battery unit temperature control device, the refrigerant that has received heat from the battery unit 2 is cooled by the air flowing through the air passage 4 while flowing through the second pipe 322 toward the radiator 31, and is also cooled by the radiator 31. Therefore, the temperature control device can efficiently cool the battery unit 2 of the electric vehicle 1. Furthermore, the temperature control device can prevent the battery unit 2 from overheating, and therefore can prevent temperature deterioration of the battery unit 2.

[0081] (Modification) 2, the thermally conductive material 5 is disposed under the case of the battery unit 2, but as illustrated in Fig. 12, for example, the thermally conductive material 5 may constitute a part of the case of the battery unit 2. In this case, the temperature control device can cool the battery unit 2 more efficiently. [Explanation of symbols]

[0082] 1 Electric vehicles 11 Floor below 12 Power unit room 2 Battery unit 21 First battery unit 22 Second battery unit 3 Refrigerant System 31 Radiator (heat exchanger) 32 Pipe 34 Fans 4 Air passage 41 Entrance 42 Exit 431 Front bulkhead (bulkhead) 432 Rear bulkhead (bulkhead) 433 Communication section 441 1st front aisle (1st aisle) 442 2nd front aisle (2nd aisle) 451 1st rear aisle (1st aisle) 452 2nd rear aisle (2nd aisle) 46 Vent 5. Thermal Conductive Materials 51 F1 valve (first opening and closing valve) 52 F2 valve (first opening and closing valve) 55 C1 valve (second opening and closing valve)

Claims

1. At least one battery unit that is located under a floor of an electric vehicle and outputs electricity for propelling the electric vehicle; a refrigerant system including a pipe through which a refrigerant that has received heat from the battery unit flows and a heat exchanger to which the pipe is connected and which dissipates heat from the refrigerant, the refrigerant circulating between the battery unit and the heat exchanger to cool the battery unit; an air passage that opens to a front and a rear of the electric vehicle and through which air flows at least while the electric vehicle is traveling; a heat conductive material interposed between the pipe and the air passage and configured to transfer heat from the refrigerant to the air in the air passage; the heat exchanger is located in a power unit room in front of the battery unit, and has a fan that receives power and generates an air flow; the air passage communicates with the power unit room through an air vent and has a second opening / closing valve that opens and closes the air vent, the second on-off valve opens the vent hole while the vehicle is stopped and the battery unit is being charged, The temperature control device for an electric vehicle battery unit, wherein the fan is driven while the vehicle is stopped and the battery unit is being charged.

2. At least one battery unit that is located under a floor of an electric vehicle and outputs electricity for propelling the electric vehicle; a refrigerant system including a pipe through which a refrigerant that has received heat from the battery unit flows and a heat exchanger to which the pipe is connected and which dissipates heat from the refrigerant, the refrigerant circulating between the battery unit and the heat exchanger to cool the battery unit; an air passage that opens to a front and a rear of the electric vehicle and through which air flows at least while the electric vehicle is traveling; a heat conductive material interposed between the pipe and the air passage and configured to transfer heat from the refrigerant to the air in the air passage; the battery unit includes a front battery unit and a rear battery unit located rearward of the front battery unit with respect to the electric vehicle; the thermally conductive material is interposed between the pipe and the air passage at a position corresponding to the front battery unit and a position corresponding to the rear battery unit, the air passage has a partition wall that divides the inside of the air passage into a first passage in contact with the thermally conductive material and a second passage away from the thermally conductive material; the partition has a communication portion that communicates between the first passage and the second passage, the communication portion being located intermediate between a position corresponding to the front battery unit and a position corresponding to the rear battery unit; The air passage is a state in which air flows through the first passage at both a position corresponding to the front battery unit and a position corresponding to the rear battery unit; a state in which air flows through the second passage at a position corresponding to the front battery unit, passes through the communication portion, and then flows through the first passage at a position corresponding to the rear battery unit; This is a temperature control device for an electric vehicle battery unit.

3. 2. The temperature control device for an electric vehicle battery unit according to claim 1, the air passage has a first opening / closing valve that opens and closes an inlet of the air passage, The first opening / closing valve closes the inlet of the air passage when the temperature of the battery unit is equal to or lower than a first temperature.

4. 2. The temperature control device for an electric vehicle battery unit according to claim 1, the battery unit includes a first battery unit and a second battery unit located rearward of the first battery unit with respect to the electric vehicle; the thermally conductive material is interposed between the pipe and the air passage at a position corresponding to the first battery unit and a position corresponding to the second battery unit, The air passage is a state in which air flows through the first battery unit and then the second battery unit; a state in which air flows to the second battery unit, bypassing the first battery unit; This is a temperature control device for an electric vehicle battery unit.

5. 2. The temperature control device for an electric vehicle battery unit according to claim 1, The fan generates an air flow from the front to the rear of the electric vehicle while the electric vehicle is traveling, The temperature control device for an electric vehicle battery unit, wherein the fan generates an air flow from the rear to the front of the electric vehicle while the electric vehicle is stopped and the battery unit is being charged.

6. 3. The temperature control device for an electric vehicle battery unit according to claim 2, The air passage further comprises: a temperature control device for an electric vehicle battery unit, wherein air flows through the first passage at a position corresponding to the front battery unit, and then passes through the communication portion, and switches to a flow state where it flows through the second passage at a position corresponding to the rear battery unit.

7. The temperature control device for an electric vehicle battery unit according to claim 2 or 6, The air passage further comprises: a temperature control device for a battery unit for an electric vehicle, wherein air flows through the first passage and the second passage at a position corresponding to the front battery unit, and then passes through the communication portion, switching to a state where air flows only through the first passage at a position corresponding to the rear battery unit.

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