Vehicle cooling system

Abstract

To utilize heat generated by a drive unit of a vehicle effectively.SOLUTION: A vehicle cooler 100 is configured to cool a drive unit 10 that drives a vehicle and a battery 13 that supplies electric power to the drive unit 10. The vehicle cooler includes a cooling channel 30 that connects the drive unit 10 and the battery 13 in series to allow a refrigerant to flow through the drive unit 10 and the battery 13. The battery 13 is connected to the downstream side of the drive unit 10.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to the structure and control of a vehicle cooling device. Background Art

[0002] A method for increasing the temperature of a battery when charging the same has been proposed. For example, Patent Document 1 discloses that before starting charging of a battery, a heater and a fan are driven by electric power from the battery, the battery is heated by heat generated by discharge of the battery and hot air from the heater and the fan, and charging of the battery is started in the heated state.

[0003] Further, Patent Document 2 discloses a method for performing temperature increase and charging of a battery by distributing charging power supplied from an external charging facility to the vehicle to the battery and a heater for the battery at a predetermined distribution ratio, and controlling to increase the distribution ratio to the heater when the temperature increase rate of the battery is less than a predetermined value. Prior Art Documents Patent Documents

[0004] Patent Document 1 Japanese Unexamined Patent Publication No. 2019-89524 Patent Document 2 Japanese Unexamined Patent Publication No. 2020-195253 Summary of the Invention Problems to be Solved by the Invention

[0005] Incidentally, an electric vehicle is provided with a cooling device that cools a drive unit for driving the vehicle. In recent years, effective utilization of heat generated in the drive unit by this cooling device has been studied. However, there is still room for improvement in the effective utilization of heat generated in the drive unit.

[0006] Therefore, an object of the vehicle cooling device of the present invention is to effectively utilize heat generated in a drive unit of a vehicle. [Means for solving the problem]

[0007] The present invention relates to a vehicle cooling device for cooling a drive unit that drives a vehicle and a battery that supplies power to the drive unit, wherein the drive unit and the battery are connected in series, and a cooling channel is provided for circulating a refrigerant between the drive unit and the battery. The system comprises: a first bypass channel connected to the cooling channel and bypassing the drive unit to allow the refrigerant to flow through the battery; a first switching valve that switches the flow of the refrigerant between the first bypass channel and the drive unit; an air conditioning unit that provides air conditioning for the passenger compartment; a heat exchanger that exchanges heat with the air conditioning unit to heat the refrigerant flowing through the cooling channel; and a control unit that adjusts the operation of the first switching valve, the air conditioning unit, and the drive unit. The aforementioned battery is connected to the downstream side of the drive unit. The drive unit includes a motor for driving the vehicle and a power control unit for adjusting the power supplied to the motor, and the control unit switches the first switching valve to allow the refrigerant to flow through the first bypass passage when the temperature of the drive unit is lower than a first set temperature, drives the air conditioning unit to heat the refrigerant with the air conditioning unit and the heat exchanger, and raises the temperature of the battery with the heated refrigerant. It is characterized by the following.

[0008] This configuration allows the heat generated by the drive unit to raise the battery temperature, effectively utilizing the heat generated by the drive unit. Furthermore, if the battery temperature is low, it can raise the battery temperature to improve the battery's charge and discharge efficiency. Furthermore, in electric vehicles, the heat generated by the motor and power control unit can be used to raise the temperature of the battery. In addition, with this configuration, when the temperature of the battery and drive unit is low, heat from the air conditioning unit can be directed into the battery, while heat from the air conditioning unit cannot be directed into the drive unit. As a result, even when the temperature of the drive unit is low, the heat from the air conditioning unit can raise the temperature of the battery in a short time.

[0013] In the vehicle cooling device of the present invention, the control unit may, when the temperature of the drive unit is equal to or higher than the first set temperature, switch the first switching valve so that the refrigerant flows through the drive unit, drive the air conditioning unit and the drive unit to heat the refrigerant with the air conditioning unit, the heat exchanger and the drive unit, and raise the temperature of the battery with the heated refrigerant.

[0014] This allows the heat generated by the drive unit to be used to raise the temperature of the battery.

[0015] The present invention relates to a vehicle cooling device for cooling a drive unit that drives a vehicle and a battery that supplies power to the drive unit, comprising: a cooling passage that connects the drive unit and the battery in series and allows a refrigerant to flow between the drive unit and the battery; a second bypass passage connected between the drive unit and the battery and bypassing the battery to allow the refrigerant to flow through it; a second switching valve that switches the flow of the refrigerant between the battery and the second bypass passage; an air conditioning unit that provides air conditioning for the passenger compartment; a heat exchanger that exchanges heat with the air conditioning unit to heat the refrigerant flowing through the cooling passage; and the second switching valve The system comprises a valve, the air conditioning unit, and a control unit that adjusts the operation of the drive unit, the battery being connected downstream of the drive unit, the drive unit including a motor for driving the vehicle and a power control unit that adjusts the power supplied to the motor, and the control unit, when the vehicle is stopped and the temperature of the drive unit is lower than a second set temperature, switches the second switching valve so that the refrigerant flows through the second bypass passage, drives the air conditioning unit to heat the refrigerant with the air conditioning unit and the heat exchanger, and heats the drive unit with the heated refrigerant. The vehicle cooling device of the present invention includes a second bypass passage connected between the drive unit and the battery, which bypasses the battery and allows the refrigerant to flow through it, and a second switching valve that switches the flow of the refrigerant between the battery and the second bypass passage. The control unit comprises, Adjust the operation of the second switching valve, the air conditioning unit, and the drive unit. death,The control unit may, when the vehicle is stationary and the temperature of the drive unit is lower than the second set temperature, switch the second switching valve so that the refrigerant flows through the second bypass passage, drive the air conditioning unit to heat the refrigerant with the air conditioning unit and the heat exchanger, and then use the heated refrigerant to raise the temperature of the drive unit.

[0016] This configuration allows the battery to heat up quickly.

[0017] In the vehicle cooling system of the present invention, the drive unit, the air conditioning unit, and the heat exchanger are housed in the front compartment of the vehicle, and a grill shutter is provided to open and close the opening of the front compartment, and the control unit may close the grill shutter when the vehicle is stopped and the temperature of the drive unit is lower than the second set temperature.

[0018] This allows the drive unit housed in the front compartment to heat up quickly, and the heat from the drive unit allows the battery to heat up quickly as well.

[0019] In the vehicle cooling device of the present invention, the control unit may, when the temperature of the drive unit is equal to or higher than the second set temperature, switch the second switching valve so that the refrigerant flows through the battery, drive the air conditioning unit and the drive unit to heat the refrigerant with the air conditioning unit, the heat exchanger and the drive unit, and raise the temperature of the battery with the heated refrigerant.

[0020] This configuration allows the battery to be heated by the heat generated by the drive unit and the heat from the air conditioning unit.

[0021] The present invention provides a vehicle cooling device for cooling a drive unit that drives a vehicle and a battery that supplies power to the drive unit, wherein the drive unit and the battery are connected in series, and the cooling device includes a cooling channel for passing a refrigerant between the drive unit and the battery, the cooling channel includes a drive unit recirculation channel for recirculating the refrigerant to the drive unit, and a battery recirculation channel for recirculating the refrigerant to the battery, and the connection mode of the drive unit recirculation channel and the battery recirculation channel can be switched between a series connection mode in which the drive unit and the battery are connected in series such that the battery is downstream of the drive unit and the refrigerant is passed between the drive unit and the battery, and a channel separation mode in which the battery recirculation channel and the drive unit recirculation channel are separated. The vehicle comprises a third switching valve, an air conditioning unit for air conditioning the passenger compartment, a heat exchanger for exchanging heat with the air conditioning unit to heat the refrigerant flowing through the cooling channel, and a control unit for adjusting the operation of the third switching valve, the air conditioning unit, and the drive unit. The battery is connected downstream of the drive unit, and the drive unit includes a motor for driving the vehicle and a power control unit for adjusting the power supplied to the motor. The control unit, when the remaining capacity of the battery falls below a set capacity while the vehicle is running, switches the third switching valve to the series connection mode, drives the air conditioning unit to heat the refrigerant with the air conditioning unit, the heat exchanger, and the drive unit, and raises the temperature of the battery with the heated refrigerant.In the vehicle cooling device of the present invention, the cooling passage includes a drive unit recirculation passage for recirculating the refrigerant to the drive unit and a battery recirculation passage for recirculating the refrigerant to the battery, and a third switching valve that switches the connection mode between the drive unit recirculation passage and the battery recirculation passage between a series connection mode in which the drive unit and the battery are connected in series such that the battery is downstream of the drive unit and the refrigerant is circulated between the drive unit and the battery, and a passage separation mode in which the battery recirculation passage and the drive unit recirculation passage are separated. The control unit comprises, Adjust the operation of the third switching valve, the air conditioning unit, and the drive unit. death, The control unit may, when the vehicle is running and the remaining capacity of the battery falls below a set capacity, switch the third switching valve to the series connection mode, drive the air conditioning unit to heat the refrigerant with the air conditioning unit, the heat exchanger, and the drive unit, and raise the temperature of the battery with the heated refrigerant.

[0022] This configuration allows the battery to be preheated while the vehicle is in motion. As a result, rapid charging can begin immediately after the vehicle stops.

[0023] In the vehicle cooling system of the present invention, the drive unit, the air conditioning unit, and the heat exchanger are housed in the front compartment of the vehicle, and a grill shutter is provided to open and close the opening of the front compartment. The control unit calculates the temperature difference between the temperature of the drive unit and the cooling start temperature at which cooling of the drive unit is required, and may close the grill shutter if the temperature difference is greater than or equal to a predetermined threshold.

[0024] This allows the drive unit housed in the front compartment to heat up quickly, and the heat from the drive unit can then quickly heat up the battery.

[0025] In the vehicle cooling device of the present invention, the cooling flow path includes a drive unit recirculation flow path that recirculates the refrigerant to the drive unit, and a battery recirculation flow path that recirculates the refrigerant to the battery, a third switching valve that switches the connection mode between the drive unit recirculation flow path and the battery recirculation flow path between a series connection mode in which the drive unit and the battery are connected in series such that the battery is located downstream of the drive unit to allow the refrigerant to flow through the drive unit and the battery, and a flow path separation mode that separates the battery recirculation flow path and the drive unit recirculation flow path The control unit comprises, adjusting the operation of said third switching valve death, The control unit may switch the third switching valve to the series connection mode to form the cooling flow path that connects the drive unit and the battery in series.

[0026] With this configuration, the cooling flow path can be switched according to the temperatures of the drive unit and the battery.

[0027] In the vehicle cooling device of the present invention, the cooling flow path includes a drive unit recirculation flow path that recirculates the refrigerant to the drive unit, and a battery recirculation flow path that recirculates the refrigerant to the battery; the device comprises a third switching valve that switches the connection mode between the drive unit recirculation flow path and the battery recirculation flow path between a series connection mode in which the drive unit and the battery are connected in series such that the battery is located downstream of the drive unit to allow the refrigerant to flow through the drive unit and the battery, and a flow path separation mode that separates the battery recirculation flow path and the drive unit recirculation flow path; the control unit adjusts the operation of the third switching valve, and the control unit may switch the third switching valve to the series connection mode to form the cooling flow path that connects the drive unit and the battery in series.

[0028] With this configuration, the cooling flow path can be switched according to the temperatures of the drive unit and the battery. Effects of the Invention

[0029] The vehicle cooling device of the present invention can effectively utilize the heat generated in the vehicle's drive unit. [Brief explanation of the drawing]

[0030] [Figure 1] This is a system diagram showing the configuration of a vehicle cooling system according to an embodiment. [Figure 2] This is a side cross-sectional view of a vehicle equipped with a vehicle cooling system according to an embodiment. [Figure 3] This is an explanatory diagram showing the connection modes of a five-way valve used in a vehicle cooling system according to the embodiment, and how to switch between connection modes. [Figure 4] This is a system diagram showing the operation of the vehicle's cooling system when the vehicle is running with the passenger compartment heated in a low-temperature environment. [Figure 5] This is a system diagram showing the operation of the vehicle's cooling system immediately after the vehicle starts up in a low-temperature environment and begins driving while heating the passenger compartment. [Figure 6] This diagram illustrates the operation of the vehicle's cooling system when the vehicle starts up in a low-temperature environment, begins driving while heating the cabin, and then the drive unit reaches a temperature above the first set temperature. [Figure 7] This flowchart shows the operation of the vehicle's cooling system when the vehicle is started in a low-temperature environment and driven while the cabin is being heated. [Figure 8] The top figure shows the time-dependent changes in the temperature of the drive unit and the battery water temperature when the vehicle is started in a low-temperature environment and driven while the cabin is being heated, and the bottom figure shows the time-dependent changes in the amount of heat transferred from the heating element, battery heater, heat pump circuit, and drive unit to the battery. [Figure 9] Figure 8 shows the breakdown of heat transferred to the battery at time t1 and time t3. [Figure 10] This diagram illustrates the operation of the vehicle's cooling system when the vehicle is started in a low-temperature environment and then stationary, providing heating to the cabin and raising the battery temperature. [Figure 11] This flowchart shows the operation of the vehicle's cooling system when the vehicle is started in a low-temperature environment and then, while stationary, the vehicle is heated inside the cabin and the battery is warmed up. [Figure 12] This is a continuation of the flowchart shown in Figure 11. [Figure 13] The first figure (top) shows the time-dependent changes in the temperature of the drive unit, battery water temperature, heat transfer medium temperature, and front compartment ambient temperature when the vehicle is started in a low-temperature environment and then heated while stationary, while the vehicle is heating the cabin and raising the battery temperature. The second figure (bottom) shows the time-dependent changes in the amount of heat transferred from the heating heater, battery heater, heat pump circuit, and drive unit to the refrigerant. [Figure 14] This flowchart shows the operation of the vehicle's cooling system when preheating the battery while the vehicle is running in a low-temperature environment. [Figure 15] This is a continuation of the flowchart shown in Figure 14. [Modes for carrying out the invention]

[0031] The vehicle cooling system 100 of the embodiment will be described below with reference to the drawings. As shown in Figure 1, the vehicle cooling system 100 is a device for cooling the drive unit 10 and the battery 13. The vehicle cooling system 100 includes a cooling channel 30, a drive unit bypass channel 45, a battery bypass channel 46, an air conditioning unit 50, a grill shutter 80, and a control unit 90. Here, the drive unit 10 includes a motor device 11 and a power control unit 12 (hereinafter referred to as PCU 12).

[0032] The cooling passage 30 is a passage through which refrigerant flows between the drive unit 10 and the battery 13. The cooling passage 30 consists of the drive unit side water pump 16, the PCU 12, the motor device 11, the battery heater 15, the battery 13, the battery side water pump 17, the chiller 18, the drive system radiator 14, the reservoir tank 19, the three-way valve 21, the five-way valve 22, and the piping connecting each of these components.

[0033] The drive unit-side water pump 16 is a pump that pressurizes the refrigerant flowing through the cooling passage 30. Here, the refrigerant may be cooling water such as LCC. The motor device 11 is a device in which the motor for vehicle drive and the transaxle are assembled together. Inside the motor device 11, there is an internal passage (not shown) through which the refrigerant flows to cool the motor device 11. The motor device 11 is fitted with a motor temperature sensor 23 for detecting the coil temperature of the motor, for example. The PCU 12 is a device that adjusts the power supplied to the motor for vehicle drive. The PCU 12 may be composed of a boost converter and an inverter, for example. The PCU 12 has an internal passage (not shown) through which the refrigerant flows to cool the PCU 12. The PCU is fitted with a PCU temperature sensor 24 for detecting the temperature of the refrigerant flowing through the internal passage. The battery heater 15 heats the refrigerant flowing through the internal passage (not shown), and the heated refrigerant raises the temperature of the battery 13. The battery 13 supplies power to the motor for vehicle drive. The battery 13, like the PCU 12, has an internal passage (not shown) through which refrigerant flows to cool the battery 13. The battery-side water pump 17 is a pump that pressurizes the refrigerant flowing through the cooling passage 30. The chiller 18 is a heat exchanger positioned between the heat pump circuit 70 (described later) and the cooling passage 30, and performs heat exchange between the refrigerant gas flowing through the heat pump circuit 70 and the refrigerant flowing through the cooling passage 30. The drive system radiator 14 has an internal passage (not shown) through which refrigerant flows, and performs heat exchange between the refrigerant and the outside air to cool the refrigerant. The reservoir tank 19 stores the refrigerant supplied to the drive unit-side water pump 16.

[0034] The three-way valve 21 is connected between the reservoir tank 19 and the drive system radiator 14. The three-way valve 21 has three ports: a first port 21a, a second port 21b, and a third port 21c. The first port 21a is the refrigerant inlet, and the second port 21b and the third port 21c are the refrigerant outlets. The three-way valve 21 is a first switching valve that switches the flow of refrigerant flowing in from the first port 21a between the second port 21b and the third port 21c. The five-way valve 22 is connected between the motor unit 11 and the battery heater 15, and between the chiller 18 and the drive system radiator 14. The five-way valve 22 has five ports, from the first port 22a to the fifth port 22e, and the connection of each port can be switched to various connection modes. The connection modes of the five-way valve 22 will be explained later with reference to Figure 3. The five-way valve 22 constitutes either a second switching valve or a third switching valve, depending on the connection mode.

[0035] The piping connecting each component of the cooling channel 30 consists of the drive unit side pump outlet pipe 32, the PCU outlet pipe 33, the motor device outlet pipe 34, the battery heater inlet pipe 35, the battery heater outlet pipe 36, the battery outlet pipe 37, the battery side water pump inlet pipe 38, the battery side water pump outlet pipe 39, the chiller outlet pipe 41, the drive system radiator inlet pipe 42, the drive system radiator outlet pipe 43, the reservoir tank inlet pipe 44, and the drive unit side pump inlet pipe 31.

[0036] The drive unit side pump outlet pipe 32 connects the outlet of the drive unit side water pump 16 to the inlet of the internal flow path of the PCU 12. The PCU outlet pipe 33 connects the outlet of the internal flow path of the PCU 12 to the inlet of the internal flow path of the motor device 11. The motor device outlet pipe 34 connects the internal flow path of the motor device 11 to the first port 22a of the five-way valve 22. The battery heater inlet pipe 35 connects the second port 22b of the five-way valve 22 to the inlet of the internal flow path of the battery heater 15. The battery heater outlet pipe 36 connects the outlet of the internal flow path of the battery heater 15 to the inlet of the internal flow path of the battery 13. The battery outlet pipe 37 connects the outlet of the internal flow path of the battery 13 to the upstream end of the battery side water pump inlet pipe 38. A battery water temperature sensor 25 for detecting the refrigerant temperature at the outlet of the battery 13 is attached to the battery outlet pipe 37. The downstream end of the battery-side water pump inlet pipe 38 is connected to the inlet of the battery-side water pump 17. The battery-side water pump outlet pipe 39 connects the outlet of the battery-side water pump 17 to the inlet of the internal refrigerant flow path of the chiller 18. The chiller outlet pipe 41 connects the outlet of the internal refrigerant flow path of the chiller 18 to the third port 22c of the five-way valve 22. The drive system radiator inlet pipe 42 connects the fourth port 22d of the five-way valve 22 to the inlet of the internal flow path of the drive system radiator 14. The drive system radiator outlet pipe 43 connects the outlet of the internal flow path of the drive system radiator 14 to the first port 21a of the three-way valve 21. The reservoir tank inlet pipe 44 connects the second port 21b of the three-way valve 21 to the reservoir tank 19. The drive unit-side pump inlet pipe 31 connects the reservoir tank 19 to the inlet of the drive unit-side water pump 16.

[0037] The drive unit bypass passage 45 connects the third port 21c of the three-way valve 21 to the motor device outlet pipe 34. The drive unit bypass passage 45 is a passage that bypasses the drive unit 10 and allows the refrigerant to flow to the battery 13. The drive unit bypass passage 45 constitutes the first bypass passage.

[0038] The battery bypass passage 46 connects the fifth port 22e of the five-way valve 22 to the upstream end of the battery-side water pump inlet pipe 38. The battery bypass passage 46 is connected between the drive unit 10 and the battery 13 and is a passage that allows refrigerant to flow through, bypassing the battery 13. The battery bypass passage 46 constitutes the second bypass passage.

[0039] The air conditioning unit 50 includes a heater circuit 60 and a heat pump circuit 70. The heater circuit 60 is a circuit that heats the heat transfer medium with a heating heater 51 to heat the passenger compartment 201 (see Figure 2). The heat pump circuit 70 is a circuit that compresses the heat transfer medium with a compressor 57 to cool or heat the passenger compartment 201. When the passenger compartment 201 is being cooled by the heat pump circuit 70, the heater circuit 60 operates to release the heat from the high-temperature refrigerant gas flowing through the heat pump circuit 70 to the outside.

[0040] The heater circuit 60 consists of a heater-side water pump 55, a water-cooled condenser 58, a heating heater 51, a heater core 52, a reservoir tank 54, an air conditioning radiator 53, a three-way control valve 56, and piping connecting these components.

[0041] The heater-side water pump 55 is a pump that pressurizes the heat transfer medium flowing through the heater circuit 60. Here, the heat transfer medium may be cooling water. The water-cooled condenser 58 is positioned across the heater circuit 60 and the heat pump circuit 70, which will be described later, and is a heat exchanger that performs heat exchange between the heat transfer medium flowing through the heater circuit 60 and the refrigerant gas flowing through the heat pump circuit 70. The water-cooled condenser 58 has an internal passage (not shown) through which the heat transfer medium flows and an internal passage (not shown) through which the refrigerant gas flows. The heating heater 51 has an electric heater that operates on power supplied from the battery 13 and an internal passage (not shown) through which the heat transfer medium flows. The heating heater 51 heats the heat transfer medium flowing through the internal passage with the electric heater. The heater core 52 has an internal passage through which the heat transfer medium flows, and by passing the heated heat transfer medium through the internal passage, it raises the temperature of the outside air to produce warm air that is blown into the passenger compartment 201. The reservoir tank 54 is a tank for storing the heat transfer medium. The air conditioning system radiator 53 has an internal flow path (not shown) through which the heat transfer medium flows, and performs heat exchange between the heat transfer medium and the outside air to cool the heat transfer medium. The air conditioning system radiator 53 and the drive system radiator 14 are connected by a heat transfer member 20, allowing heat transfer between them. The three-way control valve 56 has three ports: a first port 56a, a second port 56b, and a third port 56c. The first port 56a is the inlet for the heat transfer medium. The second port 56b and the third port 56c are the outlets for the heat transfer medium. The three-way control valve 56 adjusts the ratio of the outflow rate of the heat transfer medium from the second port 56b to the outflow rate from the third port 56c of the heat transfer medium that flows in from the first port 56a. The three-way control valve 56 can be switched between a radiator diversion mode and a radiator shutoff mode. The radiator diversion mode is a control mode in which the heat transfer medium flowing in from the first port 56a is passed through the second port 56b and the third port 56c at a predetermined ratio. The radiator shutoff mode is a mode in which the flow of heat transfer medium to the air conditioning system radiator 53 is shut off by setting the ratio of the outflow rate of heat transfer medium from the second port 56b of the three-way control valve 56 to the outflow rate of heat transfer medium from the third port 56c of the three-way control valve 56 to 100:0.

[0042] The piping connecting each component of the heater circuit 60 consists of a heater-side pump outlet pipe 62, a water-cooled condenser outlet pipe 63, a heating heater outlet pipe 64, an air conditioning system radiator inlet pipe 65, an air conditioning system radiator outlet pipe 66, a heater-side pump inlet pipe 61, a heater core inlet pipe 67, and a heater core outlet pipe 68.

[0043] The heater-side pump outlet pipe 62 connects the outlet of the heater-side water pump 55 to the inlet of the internal passage through which the heat transfer medium of the water-cooled condenser 58 flows. The water-cooled condenser outlet pipe 63 connects the outlet of the internal passage through which the heat transfer medium of the water-cooled condenser 58 flows to the inlet of the internal passage of the heating heater 51. The heating heater outlet pipe 64 connects the outlet of the internal passage of the heating heater 51 to the first port 56a of the three-way control valve 56. The air conditioning system radiator inlet pipe 65 connects the third port 56c of the three-way control valve 56 to the inlet of the internal passage of the air conditioning system radiator 53. The air conditioning system radiator outlet pipe 66 connects the outlet of the internal passage of the air conditioning system radiator 53 to the reservoir tank 54. The heater-side pump inlet pipe 61 connects the reservoir tank 54 to the inlet of the heater-side water pump 55. The heater core inlet pipe 67 connects the second port 56b of the three-way control valve 56 to the inlet of the internal flow path of the heater core 52. A heater core inlet water temperature sensor 26 is attached to the heater core inlet pipe 67 to detect the temperature of the heat transfer medium at the inlet of the heater core 52.

[0044] The heat pump circuit 70 consists of a compressor 57, a water-cooled condenser 58, an evaporator 59, a chiller 18, an evaporator-side expansion valve 78, a chiller-side expansion valve 79, and piping connecting these components.

[0045] The compressor 57 compresses the refrigerant gas flowing through the heat pump circuit 70. The water-cooled condenser 58 has an internal passage (not shown) through which the refrigerant gas flows, and performs heat exchange between the compressed and high-temperature refrigerant gas and the heat transfer medium flowing through the heater circuit 60, cooling the refrigerant gas and heating the heat transfer medium. The evaporator-side expansion valve 78 depressurizes and expands the liquid refrigerant gas at high pressure and low temperature. The evaporator 59 cools the outside air by exchanging heat between the liquid refrigerant gas and the outside air, and supplies it as cold air to the passenger compartment 201. Also, the liquid refrigerant gas evaporates and becomes a gas through heat exchange. The chiller-side expansion valve 79, like the evaporator-side expansion valve 78, depressurizes and expands the liquid refrigerant gas at high pressure and low temperature. The chiller 18 is equipped with an internal passage (not shown) through which refrigerant gas flows, and performs heat exchange between the expanded and cooled refrigerant gas and the refrigerant flowing through the cooling passage 30, thereby cooling the refrigerant flowing through the cooling passage 30.

[0046] The piping connecting each component of the heat pump circuit 70 consists of a compressor outlet pipe 71, a water-cooled condenser outlet pipe 72, an evaporator-side expansion valve outlet pipe 73, an evaporator outlet pipe 74, a chiller-side expansion valve inlet pipe 75, a chiller-side expansion valve outlet pipe 76, and a chiller outlet pipe 77.

[0047] The compressor outlet pipe 71 connects the refrigerant gas discharge port of the compressor 57 to the inlet of the internal passage (not shown) through which the refrigerant gas of the water-cooled condenser 58 flows. The water-cooled condenser outlet pipe 72 connects the outlet of the internal passage through which the refrigerant gas of the water-cooled condenser 58 flows to the evaporator-side expansion valve 78. The chiller-side expansion valve inlet pipe 75 connects the water-cooled condenser outlet pipe 72 to the chiller-side expansion valve 79. The chiller-side expansion valve outlet pipe 76 connects the chiller-side expansion valve 79 to the inlet of the internal passage through which the refrigerant gas of the chiller 18 flows. The chiller outlet pipe 77 connects the outlet of the internal passage through which the refrigerant gas of the chiller 18 flows to the refrigerant gas intake port of the compressor 57.

[0048] As shown in Figure 2, the grill shutter 80 opens and closes the front grill 203 located in front of the front compartment 202 of the vehicle 200. The front compartment 202 is a space located in front of the vehicle 200 and houses the motor unit 11, PCU 12, air conditioning unit 50, drive system radiator 14, and air conditioning system radiator 53. When the grill shutter 80 is open, outside air flows through the front grill 203 into the air conditioning system radiator 53 and drive system radiator 14 located inside the front compartment 202, cooling the refrigerant flowing through the cooling channel 30 and the heat transfer medium flowing through the heater circuit 60. When the grill shutter 80 is closed, outside air does not flow into the front compartment 202.

[0049] As shown in Figure 2, the battery 13 is located on the underside of the floor panel 204 of the vehicle 200. The passenger compartment 201 and the front compartment 202 are separated by a dash panel 205, and the air conditioning unit 50 located in the front compartment 202 has a duct that extends toward the passenger compartment 201 to supply conditioned air to the passenger compartment 201.

[0050] Returning to Figure 1, the control unit 90 is a computer equipped with a CPU 91, which is a processor that performs information processing, and a memory 92 that stores control programs and data. The operation of the control unit 90 is realized by the CPU 91 executing the control program stored in the memory 92. The motor device 11, PCU 12, drive unit side water pump 16, three-way valve 21, five-way valve 22, battery heater 15, battery side water pump 17, heating heater 51, three-way control valve 56, compressor 57, evaporator side expansion valve 78, chiller side expansion valve 79, and grill shutter 80 each operate according to commands from the control unit 90.

[0051] Furthermore, the temperature data detected by the motor temperature sensor 23, PCU temperature sensor 24, battery water temperature sensor 25, and heater core inlet water temperature sensor 26 are input to the control unit 90.

[0052] Next, the connection modes of the five-way valve 22 will be explained with reference to Figure 3. The five-way valve 22 operates in three connection modes: the flow path separation mode shown in the upper left of Figure 3, the series connection mode shown in the upper right of Figure 3, and the battery bypass series connection mode shown in the lower part of Figure 3.

[0053] The upper left diagram of Figure 3 shows the flow path separation mode. In this mode, the cooling flow path 30 is separated into a drive unit recirculation flow path 30A that recirculates the refrigerant to the drive unit 10 and a battery recirculation flow path 30B that recirculates the refrigerant to the battery 13.

[0054] As shown in the upper left diagram of Figure 3, in the flow path separation mode, the first port 22a and the fourth port 22d are in communication, the second port 22b and the third port 22c are in communication, and the fifth port 22e is closed. In addition, in the flow path separation mode, the spaces between the first port 22a and the second port 22b, and between the third port 22c and the fourth port 22d are also closed. As a result, as shown by the thick arrow in the upper left diagram of Figure 3, the refrigerant discharged from the drive unit side water pump 16 flows through the drive unit 10, the first port 22a, the fourth port 22d, the drive system radiator 14, the three-way valve 21, and the drive unit side water pump 16. This flow path constitutes the drive unit recirculation flow path 30A that recirculates the refrigerant back to the drive unit 10. Furthermore, the refrigerant discharged from the battery-side water pump 17 flows through the third port 22c, the second port 22b, the battery 13, and the battery-side water pump 17. This flow path constitutes the battery recirculation flow path 30B, which recirculates the refrigerant back to the battery 13. Thus, the flow path separation mode is a mode in which the cooling flow path 30 is separated into the drive unit recirculation flow path 30A and the battery recirculation flow path 30B.

[0055] The upper right diagram in Figure 3 shows the series connection mode. In the series connection mode, the drive unit 10 and the battery 13 are connected in series, and the refrigerant is passed through the drive unit 10 and the battery 13.

[0056] As shown in the upper right diagram of Figure 3, in series connection mode, the first port 22a and the second port 22b are in communication, the third port 22c and the fourth port 22d are in communication, and the fifth port 22e is closed. In addition, in series connection mode, the connections between the first port 22a and the fourth port 22d, and between the second port 22b and the third port 22c, which were in communication in flow path separation mode, are also closed. As a result, as shown by the thick arrows in the upper right diagram of Figure 3, the refrigerant discharged from the drive unit side water pump 16 flows through the drive unit 10, the first port 22a, the second port 22b, the battery 13, the battery side water pump 17, the third port 22c, the fourth port 22d, the drive system radiator 14, the three-way valve 21, and the drive unit side water pump 16. This flow path constitutes a cooling flow path 30 that allows refrigerant to flow between the drive unit 10 and the battery 13 by connecting the drive unit 10 and the battery 13 in series, such that the battery 13 is downstream of the drive unit 10. Thus, the series connection mode is a mode in which the drive unit return flow path 30A and the battery return flow path 30B are connected in series.

[0057] The lower diagram in Figure 3 shows the battery bypass series connection mode. In the battery bypass series connection mode, the drive unit 10 and the battery bypass flow path 46 are connected in series, bypassing the battery 13 and allowing the refrigerant to flow through to the drive unit 10.

[0058] As shown in the lower diagram of Figure 3, in the battery bypass series connection mode, the first port 22a and the fifth port 22e are in communication, the second port 22b is closed, and the third port 22c and the fourth port 22d are in communication. Also, similar to the series connection mode, the connections between the first port 22a and the fourth port 22d, and between the second port 22b and the third port 22c are closed. As a result, as shown by the thick arrows in the lower diagram of Figure 3, the refrigerant discharged from the drive unit side water pump 16 flows through the drive unit 10, the first port 22a, the fifth port 22e, the battery bypass flow path 46, the battery side water pump 17, the third port 22c, the fourth port 22d, the drive system radiator 14, the three-way valve 21, and the drive unit side water pump 16. This flow path connects the drive unit 10 and the battery bypass flow path 46 in series, bypassing the battery 13 and allowing the refrigerant to flow through to the drive unit 10.

[0059] As shown by the white arrow 95 in Figure 3, when the connection mode is switched between the flow path separation mode and the series connection mode, the five-way valve 22 functions as a third switching valve. Also, as shown by the white arrow 96 in Figure 3, when the connection mode is switched between the series connection mode and the battery bypass series connection mode, the five-way valve 22 functions as a second switching valve.

[0060] Next, with reference to Figure 4, the operation of the vehicle cooling system 100 when the vehicle 200 is running while heating the passenger compartment 201 in a low-temperature environment will be described. As shown in Figure 4, the control unit 90 switches the five-way valve 22 to the flow path separation mode. The control unit 90 also switches the three-way valve 21 to the drive unit side so that flow is possible between the first port 21a and the second port 21b. Furthermore, the control unit 90 switches the three-way control valve 56 to the radiator shut-off mode to shut off the flow of the heat transfer medium to the air conditioning system radiator 53. In this case, all of the heat transfer medium discharged from the heater-side water pump 55 flows through the heater core 52. The control unit 90 also operates the compressor 57, closing the evaporator-side expansion valve 78 and opening the chiller-side expansion valve 79. Furthermore, the control unit 90 opens the grill shutter 80.

[0061] As a result, as shown by the thick arrows in Figure 4, a drive unit recirculation channel 30A is formed through which the refrigerant flows to the drive unit side water pump 16, PCU 12, motor device 11, the first port 22a of the five-way valve 22, the fourth port 22d of the five-way valve 22, the drive system radiator 14, the three-way valve 21, and the reservoir tank 19. Additionally, a battery recirculation channel 30B is formed through which the refrigerant flows to the battery side water pump 17, chiller 18, the third port 22c, the second port 22b, the battery 13, and the battery side water pump 17. Furthermore, as shown by the double dashed arrows in Figure 4, the heat transfer medium of the heater circuit 60 flows through the heater side water pump 55, water-cooled condenser 58, heating heater 51, three-way control valve 56, heater core 52, and reservoir tank 54. Furthermore, the refrigerant gas of the heat pump circuit 70 flows through the compressor 57, water-cooled condenser 58, chiller-side expansion valve 79, and chiller 18, as shown by the thick dashed arrows in Figure 4.

[0062] The refrigerant in the drive unit recirculation channel 30A is pressurized by the drive unit side water pump 16 and flows through the PCU 12 and motor unit 11, cooling the PCU 12 and motor unit 11. The refrigerant, whose temperature has risen after flowing through the PCU 12 and motor unit 11, flows into the drive system radiator 14 through the first port 22a and fourth port 22d of the five-way valve 22. Since the grill shutter 80 is open, the refrigerant is cooled by the outside air flowing through the drive system radiator 14, and its temperature decreases. The cooled refrigerant then recirculates to the drive unit side water pump 16 through the three-way valve 21 and reservoir tank 19. In this way, the drive unit recirculation channel 30A cools the motor unit 11 and PCU 12 by recirculating the refrigerant.

[0063] The heat transfer medium in the heater circuit 60 is heated by the heating heater 51. The heated heat transfer medium, whose temperature has risen, flows into the heater core 52 and exchanges heat with the air in the passenger compartment 201. The heat transfer medium then raises the temperature of the air in the passenger compartment 201. The heat transfer medium, whose temperature has decreased due to heat exchange, circulates back to the heating heater 51 through the water-cooled condenser 58. The compressor 57 of the heat pump circuit 70 compresses the refrigerant gas. The refrigerant gas, whose temperature has increased due to compression, flows into the water-cooled condenser 58 and exchanges heat with the low-temperature heat transfer medium flowing through the heater circuit 60, heating the heat transfer medium flowing through the heater circuit 60. The refrigerant gas, whose temperature has decreased due to heat exchange in the water-cooled condenser 58, flows into the chiller 18 through the chiller-side expansion valve 79, where it exchanges heat with the refrigerant flowing through the battery recirculation channel 30B and returns to the compressor 57. In the chiller 18, heat exchange between the refrigerant and refrigerant gas occurs as heat transfer from the higher temperature to the lower temperature. The refrigerant in the battery recirculation channel 30B is heated or cooled by the heat exchange in the chiller 18 and flows into the battery heater 15 from the third port 22c and second port 22b of the five-way valve 22. When the ambient temperature is low, the refrigerant is heated by the battery heater 15 and flows into the battery 13. The temperature of the battery 13 is maintained at the temperature necessary for the vehicle 200 to run by the amount of heat heated by the battery heater 15 and the amount of heat exchanged in the chiller 18.

[0064] Next, with reference to Figures 5 to 9, the operation of the vehicle cooling system 100 in the initial stage when the vehicle 200 starts up and begins driving in a low-temperature environment will be described. In a low-temperature environment, the temperature of the battery 13 is low and the charge / discharge efficiency is low. Therefore, it is necessary to raise the temperature of the battery 13 to a temperature at which the charge / discharge efficiency of the battery 13 is high. For this purpose, the vehicle cooling system 100 is equipped with a battery heater 15 that raises the temperature of the coolant flowing through the battery 13. However, raising the temperature of the battery 13 with the battery heater 15 reduces the energy consumption of the vehicle 200. Here, energy consumption is the distance traveled per unit of energy of the vehicle 200. Therefore, the vehicle cooling system 100 of this embodiment utilizes the self-heating amount of the drive unit 10 to raise the temperature of the battery 13, thereby improving the energy consumption of the vehicle 200 in a low-temperature environment.

[0065] In step S101 of Figure 7, the control unit 90 determines whether it is necessary to raise the temperature of the battery 13. Here, whether it is necessary to raise the temperature may be determined by whether the charge and discharge efficiency of the battery 13 has decreased due to the low temperature, or by whether output limiting is necessary due to the low temperature of the battery 13. If the control unit 90 determines YES in step S101 of Figure 7, it proceeds to step S102 of Figure 7. On the other hand, if the control unit 90 determines NO in step S101 of Figure 7, it continues driving without performing the temperature-raising process for the battery 13.

[0066] In step S102 of Figure 7, the control unit 90 switches the five-way valve 22 to series connection mode. Also, in step S103 of Figure 7, the control unit 90 switches the three-way control valve 56 to radiator diversion mode. Here, as explained earlier, radiator diversion mode is a control mode that causes the heat transfer medium flowing in from the first port 56a to flow through the second port 56b and the third port 56c at a predetermined rate. As a result, a portion of the heat transfer medium heated by the heating heater 51 flows from the second port 56b through the heater core 52 to the reservoir tank 54. Another portion flows from the third port 56c through the air conditioning system radiator 53 to the reservoir tank 54.

[0067] After the control unit 90 switches the five-way valve 22 and the control mode of the three-way control valve 56, it proceeds to step S104 in Figure 7, where the motor temperature sensor 23 and the PCU temperature sensor 24 detect the temperature of the motor device 11 and the PCU 24. The temperature of the motor device 11 and the PCU 24 constitute the temperature of the drive unit 10.

[0068] The control unit 90 proceeds to step S105 in Figure 7 to determine whether the temperature of the motor unit 11 and the PCU 12 are lower than the first set temperature. Here, the first set temperature is a temperature at which the battery 13 can be heated by the heat generated by the motor unit 11 or the PCU 12, and is higher than the target temperature of the battery water temperature. For example, in a low-temperature environment, the oil inside the motor unit 11 is solidified, and the heat generated by the motor unit 11's self-heating cannot be efficiently transferred to the coolant. When the oil becomes liquid due to the self-heating of the motor unit 11 and can circulate inside the motor unit 11, the heat generated by the motor unit 11's self-heating can be effectively transferred to the coolant. For this reason, the first set temperature may be a temperature at which the oil in the motor unit 11 can circulate, and which is higher than the target temperature of the battery water temperature. Furthermore, the first set temperature may be set to different values ​​for the motor unit 11 and the PCU 12, or it may be set to the same value.

[0069] If the temperature of the motor unit 11 and the PCU 12 are lower than the first set temperature, passing refrigerant through the motor unit 11 and PCU 12 will cause the refrigerant temperature to drop, and even if the refrigerant is passed through the battery 13, the battery 13 cannot be heated up quickly. Therefore, if the control unit 90 determines YES in step S105 in Figure 7, it proceeds to step S106 in Figure 7 and switches the three-way valve 21 to the bypass side. Switching to the bypass side means connecting the first port 21a and the third port 21c, and switching the three-way valve 21 so that the refrigerant flowing in from the first port 21a flows out from the third port 21c into the drive unit bypass flow path 45. At this time, the second port 21b is closed. Then, the control unit 90 proceeds to step S107 in Figure 7 and turns on the battery heater 15.

[0070] As shown by the thick arrows in Figure 5, when the five-way valve 22 is switched to series connection mode and the three-way valve 21 is switched to bypass mode, the refrigerant in the cooling passage 30 flows through the battery-side water pump 17, chiller 18, five-way valve 22, drive system radiator 14, and three-way valve 21, and then through the drive unit bypass passage 45 to the motor device outlet pipe 34. After that, it flows from the motor device outlet pipe 34 through the five-way valve 22, battery heater 15, and battery 13. Since the battery heater 15 is on, the refrigerant in the cooling passage 30 is heated by the battery heater 15. Then, the battery 13 is heated as the heated refrigerant flows through the internal passage of the battery 13.

[0071] Furthermore, since the vehicle 200 is started in a low-temperature environment and the heating is on, the control unit 90 turns on the heating heater 51. Also, when starting in a low-temperature environment, the control unit 90 closes the grill shutter 80, so outside air is not introduced into the air conditioning system radiator 53 and the drive system radiator 14.

[0072] When the control unit 90 switches the three-way control valve 56 to radiator diversion mode, as shown by the double dashed arrow in Figure 5, part of the heat transfer medium heated by the heating heater 51 flows through the heater core 52 to heat the air in the passenger compartment 201, and the other part flows through the air conditioning system radiator 53. The air conditioning system radiator 53 and the drive system radiator 14 are connected by a heat transfer member 20. Since outside air is not introduced, the heated heat transfer medium flowing through the internal flow path of the air conditioning system radiator 53 exchanges heat with the refrigerant flowing through the internal flow path of the drive system radiator 14 via the heat transfer member 20, heating the refrigerant. The heated refrigerant in the cooling flow path 30 flows through the three-way valve 21 and the five-way valve 22 through the internal flow path of the battery 13, efficiently heating the battery 13. The refrigerant, whose temperature has decreased as it flows through the internal flow path of the battery 13, is pressurized by the battery-side water pump 17 and recirculated to the drive system radiator 14 through the five-way valve 22. In this way, the battery 13 is heated up using the heat from the heating heater 51 that heats the passenger compartment 201.

[0073] Furthermore, when the control unit 90 operates the compressor 57, closing the evaporator-side expansion valve 78 and opening the chiller-side expansion valve 79, the refrigerant gas of the heat pump circuit 70 flows through the compressor 57, water-cooled condenser 58, chiller-side expansion valve 79, and chiller 18, as shown by the thick dashed arrows in Figure 5. The refrigerant gas, pressurized by the compressor 57 and with its temperature increased, exchanges heat with the heat transfer medium flowing through the heater circuit 60 in the water-cooled condenser 58, raising the temperature of the heat transfer medium. A portion of the heat transfer medium with its increased temperature raises the temperature of the refrigerant flowing through the internal passage of the drive system radiator 14 via the air conditioning system radiator 53 and heat transfer member 20. In this way, the control unit 90 raises the temperature of the refrigerant in the cooling passage 30 by driving the compressor 57.

[0074] As explained above, after starting the vehicle 200, the valves are switched as described above to create the flow path configuration shown in Figure 5, and the battery heater 15 and heating heater 51 are turned on, and the compressor 57 is operated. The heat from the battery heater 15, the heat from the heating heater 51, and the heat from the compressor 57 heats the refrigerant in the cooling flow path 30, and the heated refrigerant can raise the temperature of the battery 13. At this time, since the three-way valve 21 is switched to the bypass side, the refrigerant does not flow through the drive unit 10. Therefore, the heat from the heating heater 51 and the heat from the compressor 57 are used exclusively to raise the temperature of the battery 13, and the battery 13 is heated up in a short time.

[0075] In step S108 of Figure 7, the control unit 90 detects the temperature of the drive unit 10 and proceeds to step S109 of Figure 7 to determine whether the temperature of the drive unit 10 has reached or exceeded the first set temperature. If the control unit 90 determines NO in step S109 of Figure 7, it continues operation with the battery heater 15 turned on in the flow path configuration shown in Figure 5, thereby raising the temperature of the battery 13.

[0076] Since the vehicle 200 is in motion, the motor unit 11 and PCU 12 are generating heat due to heat transfer resistance, etc. When the temperature of the motor unit 11 or the PCU 12 rises above the first set temperature, the heat generated by the motor unit 11 and PCU 12 can heat the refrigerant. Therefore, if the control unit 90 determines YES in step S109 in Figure 7, it proceeds to step S110 in Figure 7, where it switches the three-way valve 21 to the drive unit side and turns off the battery heater 15. Switching the three-way valve 21 to the drive unit side means connecting the first port 21a and the second port 21b, and switching the three-way valve 21 so that the refrigerant flowing in from the first port 21a flows out to the drive unit 10 from the second port 21b. At this time, the third port 21c is closed.

[0077] As described above, when the three-way valve 21 is switched to the drive unit side, the refrigerant in the cooling passage 30 flows through the drive unit side water pump 16, PCU 12, motor device 11, five-way valve 22, battery heater 15, battery 13, battery side water pump 17, chiller 18, five-way valve 22, drive system radiator 14, three-way valve 21, and reservoir tank 19, as shown by the thick arrow in Figure 6. The low-temperature refrigerant flowing out from the battery 13 is pressurized by the battery side water pump 17 and flows into the internal passage of the drive system radiator 14. The refrigerant is then heated by the heat from the heating heater 51 and the heat from the compressor 57 as it flows through the internal passage of the drive system radiator 14. The heated refrigerant is then pressurized by the drive unit side water pump 16 and flows into the PCU 12 and motor device 11. Since the temperature of the drive unit 10 is above the first set temperature, the refrigerant that has flowed through the internal flow paths of the PCU 12 and the motor device 11 is further heated by the PCU 12 and the motor device 11 before flowing into the battery 13. The heated refrigerant then recirculates back into the battery 13, raising its temperature.

[0078] Thus, in the vehicle cooling system 100, when the temperature of the drive unit 10 is above the first set temperature, the battery 13 is heated using the heat from the heating heater 51, the heat from the compressor 57, and the heat generated by the motor unit 11 and PCU 12.

[0079] Furthermore, if the control unit 90 determines NO in step S105 of Figure 7, it proceeds to step S110 of Figure 7, where it switches the three-way valve 21 to the drive unit side and turns off the battery heater 15, thereby raising the temperature of the battery 13 using the heat from the heating heater 51, the heat from the compressor 57, and the heat generated by the drive unit 10.

[0080] In step S111 of Figure 7, the control unit 90 detects the battery water temperature using the battery water temperature sensor 25, and detects the temperature of the motor unit 11 and the PCU 12 using the motor temperature sensor 23 and the PCU temperature sensor 24. The temperatures of the motor unit 11 and the PCU 12 are the temperatures of the drive unit 10. Then, in step S112 of Figure 7, the control unit 90 determines whether the battery water temperature has reached the target temperature or whether the temperature of the drive unit 10 has reached the cooling start temperature. If the control unit 90 determines NO in step S112 of Figure 7, it returns to step S111 of Figure 7 and continues to raise the temperature of the battery 13.

[0081] Furthermore, once the battery water temperature reaches the target temperature, further heating of the battery 13 is no longer necessary. On the other hand, once the temperature of the drive unit 10 reaches the cooling start temperature, cooling of the drive unit 10 must be prioritized over heating of the battery 13.

[0082] Therefore, if the control unit 90 determines YES in step S112 in Figure 7, it proceeds to step S113 in Figure 7 and switches the five-way valve 22 to flow path separation mode. Then, the control unit 90 proceeds to step S114 in Figure 7 and switches the three-way control valve 56 to radiator shut-off mode. As explained earlier, the radiator shut-off mode is a mode in which the flow of heat transfer fluid to the air conditioning system radiator 53 is shut off when the ratio of the outflow rate of heat transfer fluid from the second port 56b of the three-way control valve 56 to the outflow rate of heat transfer fluid from the third port 56c of the three-way control valve 56 is set to 100:0.

[0083] In this way, when the five-way valve 22 and the three-way control valve 56 are switched, the cooling passage 30 is separated into the drive unit recirculation passage 30A and the battery recirculation passage 30B, as explained earlier with reference to Figure 4. The refrigerant discharged from the drive unit water pump 16 then recirculates through the PCU 12, the motor unit 11, and the drive system radiator 14. The control unit 90 also opens the grill shutter 80. As a result, the refrigerant, whose temperature has risen after passing through the motor unit 11 and PCU 12, is cooled by the drive system radiator 14 and recirculates back to the motor unit 11 and PCU 12, cooling them. The vehicle then continues to operate with the flow path configuration as explained with reference to Figure 4.

[0084] Furthermore, the refrigerant discharged from the battery-side water pump 17 recirculates through the battery heater 15, the battery 13, and the chiller 18. If the battery water temperature has not reached the target temperature, the control unit 90 turns on the battery heater 15 to continue boosting the battery 13. On the other hand, if the temperature of the battery 13 has reached the target temperature, the control unit 90 keeps the battery heater 15 off.

[0085] Next, referring to Figures 8 and 9, we will explain the time changes in the amount of heat transferred from the battery heater 15, the heating heater 51, and the compressor 57 to the battery 13 when the vehicle cooling system 100 operates as described above, as well as the time changes in the battery water temperature and the temperature of the drive unit 10.

[0086] In the upper graph of Figure 8, the dashed line a1 shows the time change in the temperature of the drive unit 10 as detected by the motor temperature sensor 23 and the PCU temperature sensor 24. The solid line b1 shows the time change in the battery water temperature as detected by the battery water temperature sensor 25. In the lower graph of Figure 8, the solid line c1 shows the change in the amount of heat transferred from the heating heater 51 to the battery 13 via the heat transfer medium and refrigerant. The dashed line d1 shows the change in the amount of heat transferred from the battery heater 15 to the battery 13 via the refrigerant. The dashed line e1 shows the change in the amount of heat transferred from the compressor 57 to the battery 13 via the refrigerant gas, heat transfer medium and refrigerant. The dashed line f1 shows the amount of heat transferred from the drive unit 10, which consists of the motor device 11 and the PCU 12, to the battery 13 via the refrigerant. In Figure 8, time t0 indicates the time when the vehicle 200 was started. Time t2 is the time when the temperature of the drive unit 10 reached the first set temperature.

[0087] As shown by the solid line c1 in the lower graph of Figure 8, the amount of heat transferred from the heating element 51 to the battery 13 gradually increases from time t0 when the vehicle 200 starts and the heating element 51 is turned on. Then, after time t1 when the temperature of the battery 13 has risen to a certain extent, the amount of heat transferred from the heating element 51 to the battery 13 gradually decreases. This is because the control unit 90 increases the output of the heating element 51 in the initial stages of startup to rapidly raise the battery water temperature, and then reduces the output of the heating element 51 to a level that maintains the rate of increase in the battery water temperature after the battery water temperature has started to rise. Then, after time t3 when the amount of heat transferred from the drive unit 10, shown by the dashed line f1, becomes constant, the amount of heat transferred from the heating element 51 to the battery 13 also becomes approximately constant. As a result, the battery water temperature, shown by the solid line b1 in the upper graph of Figure 8, rises at a constant rate.

[0088] As shown by the dashed line d1 in the lower graph of Figure 8, the amount of heat transferred from the battery heater 15 to the battery 13 gradually increases from time t0 when the vehicle 200 starts and the battery heater 15 is turned on. Then, after time t1 when the temperature of the battery 13 has risen to a certain extent, the amount of heat transferred from the battery heater 15 to the battery 13 gradually decreases. This is because the control unit 90 increases the output of the battery heater 15 in the initial stages of startup to rapidly raise the battery water temperature, and then reduces the output of the battery heater 15 to a level that maintains the rate of increase in the battery water temperature after the battery water temperature has started to rise. Then, when the battery heater 15 is turned off at time t2 when the temperature of the drive unit 10 reaches the first set temperature, the amount of heat transferred from the battery heater 15 to the battery 13 becomes zero.

[0089] As shown by the dashed line e1 in the lower graph of Figure 8, the amount of heat transferred from the compressor 57 to the battery 13 gradually increases from time t0 when the vehicle 200 starts and the compressor 57 turns on. Then, after time t1 when the temperature of the battery 13 has risen to a certain extent, the amount of heat transferred from the compressor 57 to the battery 13 becomes approximately constant.

[0090] As shown by the dashed line f1 in the lower graph of Figure 8, between time t0 and time t2, no refrigerant flows through the drive unit 10, so the amount of heat transferred from the drive unit 10 to the battery 13 is zero. At time t2, the three-way valve 21 switches to the drive unit side, and when refrigerant begins to flow through the drive unit 10, the amount of heat transferred from the drive unit 10 to the battery 13 gradually increases. Then, from time t3 onward, the amount of heat transferred from the drive unit 10 to the battery 13 becomes constant.

[0091] As shown by the dashed line a1 in the upper graph of Figure 8, between time t0 and time t2, when the refrigerant is not flowing through the drive unit 10, the drive unit 10 continues to rise due to self-heating. Then, when the temperature of the drive unit 10 reaches the first set temperature at time t2, the three-way valve 21 switches to the drive unit side and the refrigerant begins to flow through the drive unit 10. As a result, the temperature of the drive unit 10 decreases temporarily due to the inflow of refrigerant, but then rises again due to self-heating.

[0092] As shown by the solid line b1 in the upper graph of Figure 8, the battery water temperature gradually rises from time t0.

[0093] Furthermore, the output of the heating element 51, the compressor 57, and the battery heater 15 are appropriately adjusted by the control unit 90 in accordance with the temperature rise of the battery 13 and the drive unit 10.

[0094] Next, referring to Figure 9, we will explain the change in the ratio of the amount of heat D transferred from the battery heater 15, the amount of heat C transferred from the heating heater 51, the amount of heat E transferred from the compressor 57, and the amount of heat F transferred from the drive unit 10.

[0095] The bar graph on the left of Figure 9 shows the ratios of heat quantities C, D, and E at time t1. As shown in the bar graph on the left of Figure 9, the heat quantity C transferred from the heating heater 51 is approximately 40% of the battery heating requirement Q1, the heat quantity E transferred from the compressor 57 is approximately 20% of the battery heating requirement Q1, and the heat quantity D transferred from the battery heater 15 is 40% of the battery heating requirement Q1. Note that at time t1, the three-way valve 21 is switched to the bypass side, so the amount of heat transferred from the drive unit 10 to the battery 13 is zero.

[0096] At time t2, the battery heater 15 is turned off, and the three-way valve 21 is on the drive unit side. Also, as the temperature of the battery 13 rises to a certain extent, the required heat quantity Q2 for battery heating at time t3 is smaller than the required heat quantity Q1 for battery heating at time t0. At time t3, the amount of heat C transferred from the heating heater 51 is approximately 20% of the required heat quantity Q2 for battery heating, the amount of heat E transferred from the compressor 57 is approximately 25% of the required heat quantity Q2 for battery heating, and the amount of heat transferred from the drive unit 10 is approximately 55% of the required heat quantity Q2 for battery heating. Thus, at time t3, 55% of the required heat quantity Q2 for battery heating can be covered by the heat generated by the drive unit 10 that is otherwise wasted to the outside through the drive system radiator 14. This improves the energy efficiency of the vehicle 200.

[0097] As explained above, in a low-temperature environment, the vehicle cooling system 100 switches the three-way valve 21 to the bypass side between time t0 and time t2 after the vehicle 200 has been started, preventing the refrigerant from flowing through the drive unit 10. This reduces the heat capacity of the equipment through which the refrigerant flows, and the battery 13 is heated up by the heat from the battery heater 15, the heating heater 51, and the compressor 57. Meanwhile, between time t0 and time t2, no refrigerant flows through the drive unit 10. As a result, the temperature of the drive unit 10 rises rapidly due to self-heating.

[0098] Then, after time t2, when the temperature of the drive unit 10 has risen to the first set temperature, the three-way valve 21 is switched to the drive unit side, the refrigerant is heated by the heat generated by the drive unit 10, and the heated refrigerant is circulated through the battery 13. As a result, after time t2, the vehicle cooling system 100 raises the temperature of the battery 13 using the heat from the battery heater 15, the heat from the heating heater 51, the heat from the compressor 57, and the heat generated by the drive unit 10. This allows the battery water temperature to be raised to the target temperature in a short time when the vehicle 200 is started. Furthermore, by raising the temperature of the battery 13 in a short time, the charge and discharge efficiency of the battery 13 can be improved in a short time. In addition, since the battery 13 is heated by the heat generated by the drive unit 10 that would otherwise be wasted outside from the drive system radiator 14, the energy consumption of the vehicle 200 can be improved.

[0099] In the above explanation, the control unit 90 was described as driving the compressor 57 after the vehicle 200 starts up and raising the temperature of the battery 13 using the heat from the compressor 57, but this is not limited to this. The control unit 90 may also raise the temperature of the battery 13 using the heat from the heating heater 51 and the heat from the battery heater 15, or the heat from the heating heater 51 and the heat generated by the drive unit 10, without driving the compressor 57 after the vehicle 200 starts up.

[0100] Furthermore, although the vehicle cooling system 100 was described as switching the cooling passage 30 using a five-way valve 22, it is not limited to this, and a combination of multiple valves may be used to enable switching of the passage in the same way as the five-way valve 22.

[0101] Next, other operations of the vehicle cooling system 100 will be described with reference to Figures 10 to 13. This operation involves heating the passenger compartment 201 and raising the temperature of the battery 13 while the vehicle 200 is stationary after it has started up in a low-temperature environment.

[0102] This operation is the opposite of the operation described earlier with reference to Figures 5 to 9. As shown in Figure 10, after the vehicle 200 is started, the three-way valve 21 is switched to the drive unit side, and the five-way valve 22 is switched to the battery bypass series mode so that the refrigerant does not flow through the battery 13. Then, the heat from the heating heater 51, the heat from the compressor 57, and the self-heating of the drive unit 10 raise the drive unit 10 to the second set temperature. After the drive unit 10 has risen to the second set temperature, as shown in Figure 6, the five-way valve 22 is switched to the series connection mode, and the heat from the heating heater 51, the heat from the compressor 57, the heat from the battery heater 15, and the heat from the drive unit 10 raise the temperature of the battery 13. This will be explained below.

[0103] As shown in step S201 of Figure 11, the control unit 90 determines whether it is necessary to raise the temperature of the battery 13. If it determines YES in step S201 of Figure 11, the control unit 90 proceeds to step S202 of Figure 11 to determine whether the vehicle 200 is stationary. Stationary status can be determined, for example, by the vehicle speed being below a predetermined threshold, the parking brake being applied, and the gear being in the parking position. If the control unit 90 determines YES in step S202 of Figure 11, it proceeds to step S203 of Figure 11.

[0104] On the other hand, if the control unit 90 determines NO in step S201 or step S202 in Figure 11, it terminates its operation without performing the temperature-raising operation of the battery 13.

[0105] In step S203 of Figure 11, the control unit 90 switches the three-way valve 21 to the drive unit side. As explained earlier, switching to the drive unit side means connecting the first port 21a and the second port 21b, and switching the three-way valve 21 so that the refrigerant flowing in from the first port 21a flows out to the drive unit 10 from the second port 21b. At this time, the third port 21c is closed. Then, the control unit 90 proceeds to step S204 of Figure 11 and switches the three-way control valve 56 to radiator diversion mode.

[0106] In step S205 of Figure 11, the control unit 90 detects the temperature of the drive unit 10, and in step S206 of Figure 11, it determines whether the temperature of the drive unit 10 is lower than the second set temperature. Here, the second set temperature is a temperature at which the heat generated by the drive unit 10 can effectively raise the temperature of the battery 13, and is higher than the target temperature of the battery water temperature. It may be set to the same temperature as the first set temperature described earlier, or it may be set to a different temperature.

[0107] If the control unit 90 determines YES in step S206 of Figure 11, it proceeds to step S207 of Figure 11 and switches the five-way valve 22 to the battery bypass series connection mode. As explained with reference to Figure 3, the battery bypass series connection mode is a mode in which the drive unit 10 and the battery bypass flow path 46 are connected in series, bypassing the battery 13 and allowing the refrigerant to flow to the drive unit 10. Also, in step S208 of Figure 11, the control unit 90 closes the grill shutter 80.

[0108] As shown by the thick arrows in Figure 10, when the three-way valve 21, three-way control valve 56, and five-way valve 22 are switched, the refrigerant in the cooling passage 30 flows from the drive unit side water pump 16 to the PCU 12, motor device 11, and five-way valve 22, and then flows from the battery bypass passage 46 to the battery side water pump inlet pipe 38. From there, it flows from the battery side water pump 17 to the chiller 18, five-way valve 22, drive system radiator 14, three-way valve 21, and reservoir tank 19.

[0109] Furthermore, since the vehicle 200 is started in a low-temperature environment and the heating is on, the control unit 90 turns on the heating heater 51. Also, since the control unit 90 closes the grill shutter 80, outside air is not introduced into the air conditioning system radiator 53 and the drive system radiator 14.

[0110] The operation of the heat pump circuit 70 is the same as described earlier with reference to Figure 5, so the explanation will be omitted.

[0111] When the cooling channel 30 and the battery bypass channel 46 are connected in this manner, the heating heater 51 is turned on, the compressor 57 is driven, and the grill shutter 80 is closed, the refrigerant in the cooling channel 30 is heated by the heat from the heating heater 51 and the heat from the compressor 57, as explained earlier with reference to Figure 5, and the drive unit 10 is heated by the heated refrigerant. At this time, the refrigerant does not flow through the battery 13, so the heat from the heating heater 51 and the heat from the compressor 57 are used exclusively to heat the drive unit 10. For this reason, the drive unit 10 is heated up in a short time. In addition, the drive unit 10 heats up through self-heating.

[0112] Furthermore, as explained with reference to Figure 2, the motor device 11 and PCU 12 that constitute the drive unit 10, and the air conditioning unit 50 are housed inside the front compartment 202. Therefore, when the temperature of the drive unit 10 rises, the ambient temperature of the front compartment 202 rises, and consequently, the drive unit 10 heats up more quickly.

[0113] In step S209 of Figure 11, the control unit 90 detects the temperature of the drive unit 10, and in step S210 of Figure 11, it determines whether the temperature of the drive unit 10 has reached or exceeded the second set temperature. If it determines NO in step S210 of Figure 11, it returns to step S209 of Figure 11 and continues to raise the temperature of the drive unit 10.

[0114] Then, if the control unit 90 determines YES in step S210 of Figure 11, it proceeds to step S211 of Figure 11 and switches the five-way valve 22 to series connection mode. Then, in step S212 of Figure 11, it turns on the battery heater 15. As a result, the flow path configuration of the vehicle cooling system 100 becomes as shown in Figure 6. As explained earlier with reference to Figure 6, the battery 13 is heated by the heat from the battery heater 15, the heat generated by the drive unit 10, the heat from the heating element 51, and the heat from the compressor 57.

[0115] In step S213 of Figure 12, the control unit 90 detects the battery water temperature and the temperature of the drive unit 10, and in step S214 of Figure 12, it determines whether the battery water temperature has reached the target temperature or whether the temperature of the drive unit 10 has reached the cooling start temperature. If the control unit 90 determines YES in step S214 of Figure 12, it switches the five-way valve 22 to the flow path separation mode in step S215 of Figure 12. The control unit 90 also switches the three-way control valve 56 to the radiator shut-off mode in step S216 of Figure 12. Then, in step S217 of Figure 12, the control unit 90 turns off the battery heater 15 and opens the grill shutter 80 in step S218 of Figure 12.

[0116] As a result, the cooling channel 30 is separated into the drive unit recirculation channel 30A and the battery recirculation channel 30B, as explained earlier with reference to Figure 4. The refrigerant discharged from the drive unit water pump 16 then recirculates through the PCU 12, the motor unit 11, and the drive system radiator 14. The refrigerant, whose temperature has risen after passing through the motor unit 11 and PCU 12, is cooled by the drive system radiator 14 and then recirculates back to the motor unit 11 and PCU 12, cooling them.

[0117] Next, referring to Figure 13, we will explain the time-dependent changes in the amount of heat transferred from the drive unit 10, the battery heater 15, the heating heater 51, and the compressor 57 to the refrigerant when the vehicle cooling system 100 operates as described above, as well as the time-dependent changes in the battery water temperature, the temperature of the drive unit 10, the ambient temperature of the front compartment 202, and the temperature of the heat transfer medium in the heater circuit 60.

[0118] In the upper graph of Figure 13, the dashed line a2 shows the time change in the temperature of the drive unit 10 as detected by the motor temperature sensor 23 and the PCU temperature sensor 24. The solid line b2 shows the time change in the battery water temperature as detected by the battery water temperature sensor 25. The dashed line g shows the time change in the temperature of the heat transfer medium in the heater circuit 60 as detected by the heater core inlet water temperature sensor 26. The dashed line h shows the time change in the ambient temperature of the front compartment 202.

[0119] Furthermore, the solid line c2 in the lower graph of Figure 13 shows the change in the amount of heat transferred from the heating heater 51 to the refrigerant via the heat transfer medium. The dashed line d2 shows the change in the amount of heat transferred from the battery heater 15 to the refrigerant. The dashed line e2 shows the change in the amount of heat transferred from the compressor 57 to the refrigerant via the refrigerant gas and heat transfer medium. The dashed line f2 shows the amount of heat transferred from the drive unit 10 to the refrigerant.

[0120] In Figure 13, time t0 indicates the time when the vehicle 200 was started. Time t13 is the time when the temperature of the drive unit 10 reaches the second set temperature, the five-way valve 22 switches from battery bypass series connection mode to series connection mode, and the battery heater 15 is turned on. Furthermore, time t15 is the time when the battery water temperature reaches the target temperature, the five-way valve 22 switches to flow path separation mode, and the three-way control valve 56 switches to radiator shut-off mode.

[0121] Therefore, between times t0 and t13, the amount of heat transferred from the heating heater 51 to the refrigerant via the heat transfer medium, the amount of heat transferred from the compressor 57 to the refrigerant via the refrigerant gas and heat transfer medium, and the amount of heat transferred from the drive unit 10 to the refrigerant are used to raise the temperature of the drive unit 10 and the refrigerant. Then, between times t13 and t15, the amount of heat transferred from the heating heater 51 to the refrigerant via the heat transfer medium, the amount of heat transferred from the compressor 57 to the refrigerant via the refrigerant gas and heat transfer medium, the amount of heat transferred from the drive unit 10 to the refrigerant, and the amount of heat transferred from the battery heater 15 to the refrigerant are used to raise the temperature of the battery 13.

[0122] As shown by the solid line c2 in the lower graph of Figure 13, the amount of heat transferred from the heating element 51 to the refrigerant gradually increases from time t0, when the vehicle 200 starts and the heating element 51 is turned on. Then, after time t11, when the temperature of the battery 13 has risen to a certain level, the amount of heat transferred from the heating element 51 to the refrigerant gradually decreases. After time t12, when the temperature of the heat transfer medium in the heater circuit 60, shown by the dashed line g in the upper graph of Figure 13, reaches a constant temperature, the amount of heat transferred from the heating element 51 to the battery 13 becomes approximately constant. Between time t0 and time t13, the amount of heat transferred from the heating element 51 to the refrigerant raises the temperature of the drive unit 10 and the refrigerant. After time t13, the amount of heat transferred from the heating element 51 to the refrigerant raises the temperature of the battery 13.

[0123] As shown by the dashed line d2 in the graph at the bottom of Figure 13, the battery heater 15 is off from time t0 to time t13, so the amount of heat transferred from the battery heater 15 to the refrigerant is zero. During this time, the battery water temperature hardly rises. At time t13, the five-way valve 22 is switched to series connection mode and the refrigerant begins to flow to the battery 13, and when the battery heater 15 is turned on, the amount of heat transferred from the battery heater 15 to the refrigerant begins to increase. After a while, the amount of heat transferred from the battery heater 15 to the refrigerant becomes constant. Then, after time t15, when the battery water temperature reaches the target temperature, the five-way valve 22 is switched to flow path separation mode and the battery heater 15 is turned off, the amount of heat transferred from the battery heater 15 to the refrigerant becomes zero. The heat transferred from the battery heater 15 to the refrigerant is used to raise the temperature of the battery 13.

[0124] As shown by the dashed line e2 in the graph at the bottom of Figure 13, the amount of heat transferred from the compressor 57 to the refrigerant gradually increases from time t0, when the vehicle 200 starts and the compressor 57 is turned on. Then, after time t11, when the temperature of the battery 13 has risen to a certain extent, the amount of heat transferred from the compressor 57 to the refrigerant becomes approximately constant. Similar to the amount of heat transferred from the heating heater 51 to the refrigerant, the amount of heat transferred from the compressor 57 to the refrigerant between time t0 and time t13 raises the temperature of the drive unit 10 and the refrigerant. Furthermore, after time t13, the amount of heat transferred from the compressor 57 to the refrigerant raises the temperature of the battery 13.

[0125] As shown by the dashed line f2 in the lower graph of Figure 13, the amount of heat transferred from the drive unit 10 to the refrigerant increases from time t0 to time t11, then gradually decreases, and then remains approximately constant. The amount of heat transferred from the drive unit 10 to the refrigerant between time t0 and time t13 raises the temperature of the refrigerant. Furthermore, from time t13 onward, the amount of heat transferred from the drive unit 10 to the refrigerant raises the temperature of the battery 13.

[0126] As shown by the dashed line a2 in the upper graph of Figure 13, the temperature of the drive unit 10 rises between time t0 and time t13 when the five-way valve 22 is in battery bypass series connection mode, and the drive unit 10 is heated by the heat from the heating heater 51, the heat from the compressor 57, and the self-heating of the drive unit 10. Also, since the grill shutter 80 is closed, the ambient temperature of the front compartment 202, shown by the dashed line h in the upper graph of Figure 13, rises. For this reason, the temperature of the drive unit 10 stored in the front compartment 202 rises in a short time.

[0127] When the temperature of the drive unit 10 reaches the second target temperature at time t13, the five-way valve 22 switches to series connection mode, and the refrigerant flows through the battery 13, starting the heating of the battery 13. As the refrigerant temperature drops slightly, the temperature of the drive unit 10 also drops slightly, but the heat from the battery heater 15 raises the temperature of the drive unit 10, so after time t14, the temperature of the drive unit 10 rises.

[0128] Furthermore, the battery water temperature, shown by the solid line b2 in the upper graph of Figure 13, hardly rises between time t0 and time t13, when no refrigerant is flowing through battery 13. After time t13, when the five-way valve 22 switches to series connection mode, refrigerant flows through battery 13, and the battery heater 15 turns on, the battery water temperature gradually rises and reaches the target temperature at time t15.

[0129] Furthermore, the output of the heating element 51, the compressor 57, and the battery heater 15 are appropriately adjusted by the control unit 90 in accordance with the temperature rise of the battery 13 and the drive unit 10.

[0130] As described above, when the vehicle 200 is started in a low-temperature environment and the vehicle 200 is stationary, the vehicle cooling system 100 switches the three-way valve 21 to the drive unit side and the five-way valve 22 to the battery bypass series connection mode, closes the grill shutter 80 and raises the ambient temperature of the front compartment 202, while the heat from the heating heater 51, the heat from the compressor 57, and the self-heating of the drive unit 10 can raise the temperature of the drive unit 10 in a short time. After the temperature of the drive unit 10 has been raised to the second set temperature, the five-way valve 22 is switched to the series connection mode, and the heat from the heating heater 51, the heat from the compressor 57, the heat from the drive unit 10, and the heat from the battery heater 15 can raise the temperature of the battery 13. As a result, when the vehicle 200 is started in a low-temperature environment and stationary, the vehicle cooling system 100 can raise the battery water temperature to the target temperature in a short time. Furthermore, by rapidly increasing the temperature of the battery 13, the charge and discharge efficiency of the battery 13 can be improved in a short time.

[0131] In this way, the vehicle cooling system 100 raises the temperature of the battery 13 by utilizing the heat generated by the drive unit 10 that is otherwise wasted from the drive system radiator 14, thereby improving the energy efficiency of the vehicle 200.

[0132] In the above explanation, the five-way valve 22 was switched to the battery bypass series connection mode so that the refrigerant bypasses the battery 13 to raise the temperature of the drive unit 10. However, the explanation is not limited to this, for example, between time t0 and time t13, the opening degree of the second port 22b of the five-way valve 22 may be adjusted to allow a small amount of refrigerant to flow between the battery heater 15 and the battery 13, thereby turning on the battery heater 15 to raise the temperature of the battery 13. Then, after time t13, the five-way valve 22 may be switched to the series connection mode, the battery heater 15 may be turned off, and the battery 13 may be raised by the heat from the heating heater 51, the heat from the compressor 57, and the heat from the drive unit 10.

[0133] Next, other operations of the vehicle cooling system 100 will be described with reference to Figures 14 and 15. As explained with reference to Figure 4, this operation preheats the battery 13 while driving when the five-way valve 22 is switched to the flow path separation mode in a low-temperature environment and the vehicle is driving while heating the passenger compartment 201, and the remaining capacity of the battery 13 (hereinafter referred to as SOC) falls below the set capacity and rapid charging is expected after the vehicle 200 stops.

[0134] The control unit 90 calculates the State of Charge (SOC) of the battery 13 while the vehicle 200 is running in the system configuration shown in Figure 4. The SOC may be calculated, for example, based on the current and voltage of the battery 13. When the SOC falls below the set capacity, the control unit 90 determines YES in step S301 in Figure 14 and proceeds to step S302 in Figure 14. If the control unit 90 determines NO in step S301 in Figure 14, it returns to step S301 in Figure 14 and waits.

[0135] The control unit 90 determines whether rapid charging may be performed after the vehicle 200 stops in step S302 of Figure 14. This determination may be made, for example, by checking whether there is a history of rapid charging after stopping in the vehicle 200's past charging history. If the control unit 90 determines YES in step S302 of Figure 14, it proceeds to step S303 of Figure 14. If the control unit 90 determines NO in step S302 of Figure 14, it determines that there is no possibility of rapid charging after stopping and that preheating of the battery 13 is not necessary, and terminates the process.

[0136] In step S303 of Figure 14, the control unit 90 determines whether there is a cooling request for the drive unit 10. If there is a cooling request, the five-way valve 22 must remain switched to the flow path separation mode, as shown in Figure 4, and the refrigerant must be cooled by the drive system radiator 14 to cool the drive unit 10. In this case, it is not possible to configure the system to preheat the battery 13. Therefore, if the control unit 90 determines YES in step S303 of Figure 14, it terminates the process without preheating the battery 13.

[0137] If the control unit 90 determines NO in step S303 of Figure 14, it proceeds to step S304 of Figure 14 and switches the five-way valve 22 to series connection mode. Also, in step S305 of Figure 14, the control unit 90 switches the three-way control valve 56 to radiator diversion mode. As a result, the system configuration of the vehicle cooling system 100 becomes the system configuration shown in Figure 6. The flow of refrigerant, heat transfer medium, and refrigerant gas at this time is the same as described earlier with reference to Figure 6. This allows the heat generated by the drive unit 10 to raise the temperature of the battery 13.

[0138] Next, in step S306 of Figure 14, the control unit 90 calculates the temperature difference DT between the temperature of the drive unit 10 and the cooling start temperature of the drive unit 10. Here, the cooling start temperature is the temperature of the drive unit 10 at which cooling is required. As explained earlier, since NO was determined in step S303 of Figure 14, the temperature of the drive unit 10 is lower than the cooling start temperature. Therefore, the control unit 90 calculates the temperature difference DT and selects a means to preheat the battery 13 based on the temperature difference DT.

[0139] As shown in step S307 of Figure 14, if the temperature difference DT is greater than or equal to the first threshold, the control unit 90 determines YES in step S307 of Figure 14 and proceeds to step S308 of Figure 14. Then, the duty cycle of the electric oil pump (hereinafter referred to as EOP) of the motor device 11 and the duty cycle of the water pump 16 on the drive unit side are reduced. This raises the temperature of the refrigerant at the outlet of the drive unit 10, allowing the battery 13 to be preheated further.

[0140] Furthermore, if the temperature difference DT is greater than or equal to a second threshold (which is greater than the first threshold), the control unit 90 determines that it may further stop the cooling system and closes the grill shutter 80 as shown in step S310 of Figure 14. As a result, outside air does not flow through the drive system radiator 14 and the air conditioning system radiator 53, so the refrigerant is heated by the heat from the heating heater 51, the heat from the compressor 57, and the heat from the drive unit 10, and the battery 13 can be further preheated with the heated refrigerant.

[0141] Furthermore, if the control unit 90 determines NO in step S307 of Figure 14, it will not reduce the duty cycle of the EOP, the duty cycle of the drive unit-side water pump 16, or close the grill shutter 80. Also, if the control unit 90 determines NO in step S309 of Figure 14, it will reduce the duty cycle of the EOP and the duty cycle of the drive unit-side water pump 16, but will not close the grill shutter 80.

[0142] Next, the control unit 90 selects a means to increase the amount of heat transferred to the battery 13 based on the SOC value of the battery 13. If the SOC is equal to or greater than the third threshold, the control unit 90 determines YES in step S311 of Figure 14 and proceeds to step S312 of Figure 14, where it may increase the self-heating of the drive unit 10 and raise the temperature of the coolant to preheat the battery 13, for example by increasing the current supplied to the motor device 11 and raising the temperature of the motor device 11. Here, the third threshold is a value smaller than the set capacity in step S301.

[0143] Furthermore, if the SOC is greater than the third threshold and less than the set capacity (i.e., greater than or equal to the fourth threshold) in step S313 of Figure 14, the control unit 90 determines YES in step S313 of Figure 14 and proceeds to step S314 of Figure 14 to turn on the battery heater 15.

[0144] Furthermore, if the control unit 90 determines NO in step S311 of Figure 14, it will not perform the self-heating increase process of the drive unit 10 and will not turn on the battery heater 15. Also, if the control unit 90 determines NO in step S313 of Figure 14, it will perform the self-heating increase process of the drive unit 10, but will not turn on the battery heater 15.

[0145] In this way, the control unit 90 can select a means to raise the temperature of the battery 13 according to the temperature state of the drive unit 10 and the state of charge (SOC) of the battery 13, thereby effectively preheating the battery 13.

[0146] As explained above, the vehicle cooling system 100 can preheat the battery 13 while the vehicle 200 is running. Therefore, rapid charging can be performed immediately after the vehicle 200 stops. [Explanation of symbols]

[0147] 10 Drive unit, 11 Motor device, 12 PCU (Power Control Unit), 13 Battery, 14 Drive system radiator, 15 Battery heater, 16 Drive unit side water pump, 17 Battery side water pump, 18 Chiller, 19, 54 Reservoir tank, 20 Heat transfer element, 21 Three-way valve, 22 Five-way valve, 23 Motor temperature sensor, 24 PCU temperature sensor, 25 Battery water temperature sensor, 26 Heater core inlet water temperature sensor, 30 Cooling passage, 30A Drive unit recirculation passage, 30B Battery recirculation passage, 31 Drive unit side pump inlet pipe, 32 Drive unit side pump outlet pipe, 33 PCU outlet pipe, 34 Motor device outlet pipe, 35 Battery heater inlet pipe, 36 Battery heater outlet pipe, 37 Battery outlet pipe, 38 Battery side water pump inlet pipe, 39 Battery side water pump outlet pipe, 41 Chiller outlet pipe, 42 Drive system radiator inlet pipe, 43 Drive system radiator outlet pipe, 44 Reservoir tank inlet pipe, 45 Drive unit bypass passage, 46 Battery bypass passage, 50 Air conditioning unit, 51 Heating heater, 52 Heater core, 53 Air conditioning system radiator, 55 Heater side water pump, 56 Three-way control valve, 57 Compressor, 58 Water-cooled condenser, 59 Evaporator, 60 Heater circuit, 61 Heater side pump inlet pipe, 62 Heater side pump outlet pipe, 63 Water-cooled condenser outlet pipe, 64 Heating heater outlet pipe, 65 Air conditioning system radiator inlet pipe, 66 Air conditioning system radiator outlet pipe, 67 Heater core inlet pipe, 68 Heater core outlet pipe, 70 Heat pump circuit, 71 Compressor outlet pipe, 72 Water-cooled condenser outlet pipe, 73 Evaporator side expansion valve outlet pipe, 74 Evaporator outlet pipe, 75 Chiller-side expansion valve inlet pipe, 76 Chiller-side expansion valve outlet pipe, 77 Chiller outlet pipe, 78 Evaporator-side expansion valve, 79 Chiller-side expansion valve, 80 Grill shutter, 90 Control unit, 91 CPU 92 Memory, 100 Vehicle cooling system, 200 Vehicle, 201 Passenger compartment, 202 Front compartment, 203 Front grille, 204 Floor panel, 205 Dash panel.

Claims

1. A vehicle cooling device for cooling a drive unit that drives a vehicle and a battery that supplies power to the drive unit, The drive unit and the battery are connected in series, and a cooling channel is provided to allow refrigerant to flow between the drive unit and the battery, A first bypass channel is connected to the cooling channel and bypasses the drive unit to allow the refrigerant to flow through the battery, A first switching valve that switches the flow of the refrigerant between the first bypass passage and the drive unit, An air conditioning unit that provides air conditioning for the passenger compartment, A heat exchanger that exchanges heat with the air conditioning unit and heats the refrigerant flowing through the cooling channel, The system comprises the first switching valve, the air conditioning unit, and a control unit that adjusts the operation of the drive unit, The aforementioned battery is connected to the downstream side of the drive unit, The drive unit includes a motor for driving the vehicle and a power control unit that adjusts the power supplied to the motor. The control unit, when the temperature of the drive unit is lower than the first set temperature, switches the first switching valve so that the refrigerant flows through the first bypass passage, drives the air conditioning unit to heat the refrigerant with the air conditioning unit and the heat exchanger, and raises the temperature of the battery with the heated refrigerant. A vehicle cooling system characterized by the following features.

2. A vehicle cooling device according to claim 1, The control unit, when the temperature of the drive unit is equal to or higher than the first set temperature, switches the first switching valve so that the refrigerant flows through the drive unit, drives the air conditioning unit and the drive unit to heat the refrigerant with the air conditioning unit, the heat exchanger and the drive unit, and raises the temperature of the battery with the heated refrigerant. A vehicle cooling system characterized by the following features.

3. A vehicle cooling device for cooling a drive unit that drives a vehicle and a battery that supplies power to the drive unit, The drive unit and the battery are connected in series, and a cooling channel is provided to allow refrigerant to flow between the drive unit and the battery, A second bypass channel is connected between the drive unit and the battery, and bypasses the battery to allow the refrigerant to flow through. A second switching valve that switches the flow of the refrigerant between the battery and the second bypass flow path, An air conditioning unit that provides air conditioning for the passenger compartment, A heat exchanger that exchanges heat with the air conditioning unit to heat the refrigerant flowing through the cooling channel, The system comprises the second switching valve, the air conditioning unit, and a control unit that adjusts the operation of the drive unit, The aforementioned battery is connected to the downstream side of the drive unit, The drive unit includes a motor for driving the vehicle and a power control unit that adjusts the power supplied to the motor. The control unit, when the vehicle is stationary and the temperature of the drive unit is lower than the second set temperature, switches the second switching valve so that the refrigerant flows through the second bypass passage, drives the air conditioning unit to heat the refrigerant with the air conditioning unit and the heat exchanger, and uses the heated refrigerant to raise the temperature of the drive unit. A vehicle cooling system characterized by the following features.

4. A vehicle cooling device according to claim 1, A second bypass channel is connected between the drive unit and the battery, and bypasses the battery to allow the refrigerant to flow through. The system includes a second switching valve that switches the flow of the refrigerant between the battery and the second bypass flow path, The control unit adjusts the operation of the second switching valve, the air conditioning unit, and the drive unit. The control unit, when the vehicle is stationary and the temperature of the drive unit is lower than the second set temperature, switches the second switching valve so that the refrigerant flows through the second bypass passage, drives the air conditioning unit to heat the refrigerant with the air conditioning unit and the heat exchanger, and uses the heated refrigerant to raise the temperature of the drive unit. A vehicle cooling system characterized by the following features.

5. A vehicle cooling device according to Claim 2, A second bypass channel is connected between the drive unit and the battery, and bypasses the battery to allow the refrigerant to flow through. The system includes a second switching valve that switches the flow of the refrigerant between the battery and the second bypass flow path, The control unit adjusts the operation of the second switching valve, the air conditioning unit, and the drive unit. The control unit, when the vehicle is stationary and the temperature of the drive unit is lower than the second set temperature, switches the second switching valve so that the refrigerant flows through the second bypass passage, drives the air conditioning unit to heat the refrigerant with the air conditioning unit and the heat exchanger, and uses the heated refrigerant to raise the temperature of the drive unit. A vehicle cooling system characterized by the following features.

6. A vehicle cooling device according to any one of claims 3 to 5, The drive unit, the air conditioning unit, and the heat exchanger are housed in the front compartment of the vehicle. The front compartment is equipped with a grille shutter that opens and closes the opening, The control unit closes the grill shutter when the vehicle is stationary and the temperature of the drive unit is lower than the second set temperature. A vehicle cooling system characterized by the following features.

7. A vehicle cooling device according to any one of claims 3 to 5, The control unit, when the temperature of the drive unit is equal to or higher than the second set temperature, switches the second switching valve so that the refrigerant flows through the battery, drives the air conditioning unit and the drive unit to heat the refrigerant with the air conditioning unit, the heat exchanger and the drive unit, and raises the temperature of the battery with the heated refrigerant. A vehicle cooling system characterized by the following features.

8. A vehicle cooling device according to claim 6, The control unit, when the temperature of the drive unit is equal to or higher than the second set temperature, switches the second switching valve so that the refrigerant flows through the battery, drives the air conditioning unit and the drive unit to heat the refrigerant with the air conditioning unit, the heat exchanger and the drive unit, and raises the temperature of the battery with the heated refrigerant. A vehicle cooling system characterized by the following features.

9. A vehicle cooling device for cooling a drive unit that drives a vehicle and a battery that supplies power to the drive unit, The drive unit and the battery are connected in series, and a cooling channel is included for passing a refrigerant between the drive unit and the battery. The cooling channel includes a drive unit recirculation channel for recirculating the refrigerant to the drive unit, and a battery recirculation channel for recirculating the refrigerant to the battery. A third switching valve switches the connection mode between the drive unit recirculation channel and the battery recirculation channel between a series connection mode in which the drive unit and the battery are connected in series such that the battery is downstream of the drive unit, and the refrigerant is passed through the drive unit and the battery, and a channel separation mode in which the battery recirculation channel and the drive unit recirculation channel are separated. An air conditioning unit that provides air conditioning for the passenger compartment, A heat exchanger that exchanges heat with the air conditioning unit to heat the refrigerant flowing through the cooling channel, The system comprises the third switching valve, the air conditioning unit, and a control unit that adjusts the operation of the drive unit, The aforementioned battery is connected to the downstream side of the drive unit, The drive unit includes a motor for driving the vehicle and a power control unit that adjusts the power supplied to the motor. The control unit, when the remaining capacity of the battery falls below a set capacity while the vehicle is running, switches the third switching valve to the series connection mode, drives the air conditioning unit to heat the refrigerant with the air conditioning unit, the heat exchanger, and the drive unit, and raises the temperature of the battery with the heated refrigerant. A vehicle cooling system characterized by the following features.

10. A vehicle cooling device according to claim 1, The cooling channel includes a drive unit recirculation channel for recirculating the refrigerant to the drive unit, and a battery recirculation channel for recirculating the refrigerant to the battery. The system includes a third switching valve that switches the connection mode between the drive unit recirculation channel and the battery recirculation channel between a series connection mode in which the drive unit and the battery are connected in series such that the battery is downstream of the drive unit, and the refrigerant is passed through the drive unit and the battery, and a channel separation mode in which the battery recirculation channel and the drive unit recirculation channel are separated. The control unit adjusts the operation of the third switching valve, the air conditioning unit, and the drive unit. The control unit, when the remaining capacity of the battery falls below a set capacity while the vehicle is running, switches the third switching valve to the series connection mode, drives the air conditioning unit to heat the refrigerant with the air conditioning unit, the heat exchanger, and the drive unit, and raises the temperature of the battery with the heated refrigerant. A vehicle cooling system characterized by the following features.

11. A vehicle cooling device according to claim 2, The cooling channel includes a drive unit recirculation channel for recirculating the refrigerant to the drive unit, and a battery recirculation channel for recirculating the refrigerant to the battery. The system includes a third switching valve that switches the connection mode between the drive unit recirculation channel and the battery recirculation channel between a series connection mode in which the drive unit and the battery are connected in series such that the battery is downstream of the drive unit, and the refrigerant is passed through the drive unit and the battery, and a channel separation mode in which the battery recirculation channel and the drive unit recirculation channel are separated. The control unit adjusts the operation of the third switching valve, the air conditioning unit, and the drive unit. The control unit, when the remaining capacity of the battery falls below a set capacity while the vehicle is running, switches the third switching valve to the series connection mode, drives the air conditioning unit to heat the refrigerant with the air conditioning unit, the heat exchanger, and the drive unit, and raises the temperature of the battery with the heated refrigerant. A vehicle cooling system characterized by the following features.

12. A vehicle cooling device according to any one of claims 9 to 11, The drive unit, the air conditioning unit, and the heat exchanger are housed in the front compartment of the vehicle. The front compartment is equipped with a grille shutter that opens and closes the opening, The control unit calculates the temperature difference between the temperature of the drive unit and the temperature at which cooling of the drive unit is required to begin, and closes the grill shutter when the temperature difference is greater than or equal to a predetermined threshold. A vehicle cooling system characterized by the following features.

13. A vehicle cooling device according to claim 1 or 2, The cooling channel includes a drive unit recirculation channel for recirculating the refrigerant to the drive unit, and a battery recirculation channel for recirculating the refrigerant to the battery. The system includes a third switching valve that switches the connection mode between the drive unit recirculation channel and the battery recirculation channel between a series connection mode in which the drive unit and the battery are connected in series such that the battery is downstream of the drive unit, and the refrigerant is passed through the drive unit and the battery, and a channel separation mode in which the battery recirculation channel and the drive unit recirculation channel are separated. The control unit adjusts the operation of the third switching valve, The control unit switches the third switching valve to the series connection mode to configure the cooling path that connects the drive unit and the battery in series. A vehicle cooling system characterized by the following features.

14. A vehicle cooling device according to any one of claims 3 to 5, The cooling channel includes a drive unit recirculation channel for recirculating the refrigerant to the drive unit, and a battery recirculation channel for recirculating the refrigerant to the battery. The system includes a third switching valve that switches the connection mode between the drive unit recirculation channel and the battery recirculation channel between a series connection mode in which the drive unit and the battery are connected in series such that the battery is downstream of the drive unit, and the refrigerant is passed through the drive unit and the battery, and a channel separation mode in which the battery recirculation channel and the drive unit recirculation channel are separated. The control unit adjusts the operation of the third switching valve, The control unit switches the third switching valve to the series connection mode to configure the cooling path that connects the drive unit and the battery in series. A vehicle cooling system characterized by the following features.

15. A vehicle cooling device according to claim 7, The cooling channel includes a drive unit recirculation channel for recirculating the refrigerant to the drive unit, and a battery recirculation channel for recirculating the refrigerant to the battery. The system includes a third switching valve that switches the connection mode between the drive unit recirculation channel and the battery recirculation channel between a series connection mode in which the drive unit and the battery are connected in series such that the battery is downstream of the drive unit, and the refrigerant is passed through the drive unit and the battery, and a channel separation mode in which the battery recirculation channel and the drive unit recirculation channel are separated. The control unit adjusts the operation of the third switching valve, The control unit switches the third switching valve to the series connection mode to configure the cooling path that connects the drive unit and the battery in series. A vehicle cooling system characterized by the following features.

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