Vehicle thermal management systems

Abstract

This system prevents the radiator from absorbing waste heat from the outdoor condenser during battery cooling via the chiller, thereby ensuring proper thermal management of the drive system. [Solution] The thermal management system S includes a refrigerant circuit 20, a chiller 30, a first circuit 100 for adjusting the temperature of the battery B, a second circuit 200 for adjusting the temperature of the drive unit E, a third circuit 300 having a radiator 301, and a fourth circuit 400 connected to the chiller 30. The control unit 600 performs battery cooling by connecting the first circuit 100 and the fourth circuit 400, and drive unit cooling by connecting the second circuit 200 and the third circuit 300. While performing battery cooling and drive unit cooling, the control unit 600 performs heat absorption suppression control to suppress the absorption of heat released from the outdoor condenser 23 into the radiator 301.

Description

Technical Field

[0001] The present disclosure relates to a vehicle thermal management system mounted on, for example, an electric vehicle.

Background Art

[0002] Patent Document 1 discloses a thermal management system for an electric vehicle that supplies power from an in-vehicle battery to a drive motor and runs by the power of the drive motor. In the thermal management system of Patent Document 1, it includes a refrigeration cycle in which a refrigerant circulates, a battery temperature control circuit in which a coolant circulates, and a chiller connected to the refrigeration cycle and the battery temperature control circuit. In the chiller, the coolant circulating in the battery circuit and the refrigerant circulating in the refrigeration cycle can exchange heat. Further, the thermal management system of Patent Document 1 includes a low-temperature circuit having a radiator for cooling the drive device as a circuit independent of the battery temperature control circuit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The vehicle's thermal management system includes a chiller connected to both the battery temperature control circuit and the refrigeration cycle. This allows for temperature control of the battery by using the coolant in the battery temperature control circuit, which is temperature-controlled through heat exchange with the refrigerant in the refrigeration cycle. Furthermore, the waste heat from the battery temperature control circuit can be effectively utilized for heating the refrigeration cycle, leading to reduced power consumption. Additionally, the battery temperature control circuit and the low-temperature circuit that cools the drive unit are independent circuits. This allows for separate temperature control of the battery by the battery temperature control circuit and temperature control of the drive unit by the low-temperature circuit, resulting in proper thermal management of both the battery and the drive unit.

[0005] Incidentally, if the battery generates a large amount of heat, the amount of heat absorbed by the refrigerant in the refrigeration cycle from the coolant via the chiller increases, resulting in increased heat dissipation from the outdoor condenser of the refrigeration cycle. Since the outdoor condenser is located outside the vehicle along with the radiator of the low-temperature circuit, it is possible that the radiator may absorb the waste heat from the outdoor condenser, which could lead to a decrease in the radiator's heat dissipation capacity. A decrease in the radiator's heat dissipation capacity could impair the thermal management of the drive system.

[0006] This disclosure is made in view of the above, and its purpose is to suppress the absorption of waste heat from the outdoor condenser by the radiator when the battery is cooled via the chiller, thereby enabling proper thermal management of the drive unit. [Means for solving the problem]

[0007] To achieve the above objective, one aspect of this disclosure may be based on a vehicle thermal management system installed in a vehicle that runs on power supplied from a battery to a drive unit. The vehicle thermal management system comprises a refrigerant circuit having a compressor for compressing a refrigerant, an outdoor condenser into which the refrigerant compressed by the compressor flows, and a chiller expansion valve for expanding the refrigerant that has flowed out of the outdoor condenser; a chiller connected between the chiller expansion valve and the compressor of the refrigerant circuit; a first circuit configured to allow the flow of a heat transfer medium and to adjust the temperature of the battery using the flowing heat transfer medium; a second circuit configured to allow the flow of the heat transfer medium and to adjust the temperature of the drive unit using the flowing heat transfer medium; a third circuit configured to allow the flow of the heat transfer medium and having a radiator for exchanging heat between the flowing heat transfer medium and the outside air; and a fourth circuit configured to allow the flow of the heat transfer medium and connected to the chiller. The vehicle thermal management system further includes a control unit that performs battery cooling by connecting the first circuit and the fourth circuit, and drive unit cooling by connecting the second circuit and the third circuit, and performs heat absorption suppression control to suppress the absorption of heat released from the outdoor condenser into the radiator during the execution of the battery cooling and the drive unit cooling.

[0008] In this configuration, when the battery is being cooled, the first and fourth circuits are connected, so the heat transfer medium absorbed from the battery exchanges heat with the refrigerant expanded by the chiller expansion valve in the refrigerant circuit via the chiller, causing its temperature to drop. This cooled heat transfer medium is then supplied to the battery by the first circuit to cool the battery. In this process of cooling the battery using the heat transfer medium, heat is released from the outdoor condenser of the refrigerant circuit.

[0009] On the other hand, when the drive unit is being cooled, the second and third circuits are connected, so the heat transfer medium absorbed from the drive unit exchanges heat with the outside air via the radiator, causing its temperature to drop. This cooled heat transfer medium is then supplied to the drive unit by the second circuit, and the drive unit is cooled.

[0010] During battery cooling and drive unit cooling, for example, if the battery generates a lot of heat, the amount of heat dissipated from the outdoor condenser of the refrigerant circuit increases. In such situations, the technology according to this disclosure has a control unit that performs heat absorption suppression control. This suppresses the absorption of heat released from the outdoor condenser into the radiator, thereby enabling cooling of the drive unit.

[0011] The vehicle thermal management system may further include a drive unit temperature sensor that acquires the temperature of the drive unit. The control unit determines whether the temperature of the drive unit acquired by the drive unit temperature sensor is equal to or greater than a first temperature, and if it is determined that the temperature of the drive unit acquired by the drive unit temperature sensor is equal to or greater than the first temperature, it can execute the heat absorption suppression control. As a result, when the temperature of the drive unit is high and cooling of the drive unit is required, the heat released from the outdoor condenser is less likely to be absorbed by the radiator, so that the temperature of the drive unit can be properly managed.

[0012] The vehicle thermal management system may further include a battery temperature sensor that acquires the temperature of the battery. The control unit determines whether the temperature of the battery acquired by the battery temperature sensor is equal to or greater than a second temperature, and if it is determined that the temperature of the battery acquired by the battery temperature sensor is equal to or greater than the second temperature, it can execute the heat absorption suppression control. Although not particularly limited, for example, the first temperature can be set higher than the second temperature. That is, when the battery temperature is high and a large amount of heat is released from the outdoor condenser, the heat released from the outdoor condenser is less likely to be absorbed by the radiator, so that the temperature of the drive unit can be properly managed.

[0013] The control unit can execute the heat absorption suppression control when it is determined that the temperature of the drive unit, as obtained by the drive unit temperature sensor, is equal to or greater than the first temperature, and the temperature of the battery, as obtained by the battery temperature sensor, is equal to or greater than the second temperature.

[0014] In the heat absorption suppression control described above, the control unit may execute a control that restricts the chiller expansion valve compared to before the heat absorption suppression control was executed. This reduces the amount of heat released from the outdoor condenser, making it less likely for the heat released from the outdoor condenser to be absorbed by the radiator.

[0015] The refrigerant circuit may include a cooling expansion valve that expands the refrigerant flowing out from the outdoor condenser, and a cooling evaporator into which the refrigerant expanded by the cooling expansion valve flows. In this case, the control unit executes the heat absorption suppression control when the refrigerant circuit is used for indoor cooling operation, and in the heat absorption suppression control during cooling operation, the cooling expansion valve can be throttled compared to before the heat absorption suppression control was executed. By throttling the cooling expansion valve, the amount of heat released from the outdoor condenser can be reduced, making it less likely for the heat released from the outdoor condenser to be absorbed by the radiator.

[0016] After executing control to throttle the chiller expansion valve, the control unit determines whether the temperature of the drive unit, as obtained by the drive unit temperature sensor, exceeds the third temperature. If it is determined that the temperature of the drive unit, as obtained by the drive unit temperature sensor during cooling operation, exceeds the third temperature, the control unit can execute both control to throttle the chiller expansion valve and control to throttle the cooling expansion valve. This further reduces the amount of heat released from the outdoor condenser.

[0017] The control unit determines whether the temperature of the drive unit, as obtained by the drive unit temperature sensor during cooling operation, exceeds a fourth temperature higher than the third temperature. If it is determined that the temperature of the drive unit, as obtained by the drive unit temperature sensor during cooling operation, exceeds the fourth temperature, the control unit can perform a control in the heat absorption suppression control that reduces the rotational speed of the compressor compared to before the heat absorption suppression control was performed. By reducing the rotational speed of the compressor, the amount of heat released from the outdoor condenser can be further reduced. In this heat absorption suppression control, the compressor may be stopped.

Advantages of the Invention

[0018] As described above, since the radiator can be suppressed from absorbing the waste heat of the outdoor condenser when cooling the battery through the chiller, the heat management of the drive device can be appropriately performed.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is a functional block diagram of a vehicle thermal management system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically showing an electric vehicle equipped with a vehicle thermal management system. [Figure 3] FIG. 3 is a diagram showing the flow of refrigerant and coolant during the first cooling operation for cooling the battery and the drive device. [Figure 4] FIG. 4 is a diagram showing the flow of refrigerant and coolant during the second cooling operation for cooling the battery and the drive device. [Figure 5] FIG. 5 is a flowchart showing the control flow by the control unit. [Figure 6] FIG. 6 is a timing chart when the control by the control unit is applied. [Figure 7] FIG. 7 is a diagram showing the flow of refrigerant and coolant during the third cooling operation for cooling the battery and the drive device. [

Embodiments for Carrying Out the Invention

[0020] <( Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses. For example, the relative sizes and positional relationships of the components shown in the figures are for the purpose of explaining one embodiment and do not limit the present invention.

[0021] Figure 1 is a functional block diagram of a vehicle thermal management system (hereinafter referred to as the "thermal management system") S according to an embodiment of the present invention. The thermal management system S is mounted on an electric vehicle 1 schematically shown in Figure 2. That is, the electric vehicle 1 is equipped with a front motor MA and a rear motor MB, and a battery B.

[0022] The front motor MA and rear motor MB are drive motors and traction motors that generate the driving force necessary to propel the electric vehicle 1. The front motor MA drives the front wheels, and the rear motor MB drives the rear wheels. Both the front motor MA and the rear motor MB may be mounted on the electric vehicle 1, or only one of them may be mounted on the electric vehicle 1.

[0023] Battery B is not an auxiliary battery, but a high-capacity secondary battery for driving that supplies power to the front motor MA and rear motor MB. A typical example of Battery B is a lithium-ion battery, but the present invention can be applied to any rechargeable battery other than a lithium-ion battery (e.g., a nickel-metal hydride battery). In the case of a lithium-ion battery, its shape may be, for example, pouch-type or cylindrical. When the electric vehicle 1 is braking, the energy regenerated by the front motor MA and rear motor MB is stored as electricity in Battery B.

[0024] The electric vehicle 1 includes a front inverter IA that controls the front motor MA and a rear inverter IB that controls the rear motor MB. For example, the electric vehicle 1 may include a front e-axle (not shown) which includes the front motor MA, the front inverter IA, and a front transaxle (not shown). Alternatively, the electric vehicle 1 may include a rear e-axle (not shown) which includes the rear motor MB, a rear inverter IB, and a rear transaxle (not shown).

[0025] Electric vehicle 1 is equipped with a DC / DC converter and a charge controller (collectively referred to as C). The DC / DC converter and charge controller C are devices that supply current from an external charger (not shown) and supply it to battery B as a charging current of a suitable magnitude for charging battery B. In other words, battery B is charged via the DC / DC converter and charge controller C. Battery B can be charged using both normal charging with a maximum power of 11 kW and fast charging with a power exceeding 11 kW. Hereinafter, "DC / DC converter and charge controller" will simply be referred to as "charge controller". The charge controller receives the alternating current during normal charging.

[0026] Although not an essential component, electric vehicle 1 is equipped with a power supply unit D. Power supply unit D is a device for supplying power from battery B to an external source and includes, for example, an inverter configured to output 100V power.

[0027] The front motor MA, rear motor MB, front inverter IA, rear inverter IB, and charge controller C are examples of elements that constitute the drive system E for driving the electric vehicle 1. The electric vehicle 1 runs by supplying power from the battery B to the drive system E. In this embodiment, the charge controller C is included as part of the drive system E, but the charge controller C does not have to be a component of the drive system E. The power supply unit D may or may not be included as a component of the drive system E. In addition to the equipment described above, the drive system E may also include equipment related to the driving of the electric vehicle 1. Furthermore, equipment that does not require temperature control may be excluded from the drive system E of the present invention.

[0028] In this embodiment, the case in which the thermal management system S is installed in an electric vehicle 1 is described, but it is not limited to this, and for example, the thermal management system S can also be installed in a plug-in hybrid vehicle. When the thermal management system S is installed in a plug-in hybrid vehicle, similar effects and advantages can be achieved.

[0029] The thermal management system S includes a refrigerant circuit 20 through which a refrigerant circulates, and a chiller 30 for utilizing the cold generated in the refrigerant circuit 20, for example, for cooling a battery B. Separate from the refrigerant circuit 20 through which the refrigerant circulates, the thermal management system S also includes, for example, a first circuit 100, a second circuit 200, a third circuit 300, and a fourth circuit 400, which are configured to allow the flow of a heat transfer medium.

[0030] The first circuit 100 is a circuit for adjusting the temperature of battery B using a circulating heat transfer medium. The second circuit 200 is a circuit for adjusting the temperature of drive unit E using a circulating heat transfer medium. The third circuit 300 is a circuit having a radiator 301 that dissipates heat by exchanging heat between the circulating heat transfer medium and the outside air. The fourth circuit 400 is a circuit connected to chiller 30. The heat transfer medium circulating in the first circuit 100, the second circuit 200, the third circuit 300, and the fourth circuit 400 is, for example, coolant. In the following description, the heat transfer medium will be described as coolant.

[0031] The thermal management system S further includes an electrically operated 8-way valve 500 for switching the connection states of the first circuit 100, the second circuit 200, the third circuit 300, and the fourth circuit 400, and a control unit 600 for controlling each of the devices included in the thermal management system S. The 8-way valve 500 may be included in the control unit 600. First, the specific configurations of the refrigerant circuit 20, the first circuit 100, the second circuit 200, the third circuit 300, and the fourth circuit 400 will be described, but the following description is an example and may include other components that are not described.

[0032] (Refrigerant circuit configuration) First, let's describe the refrigerant circuit 20. The refrigerant circuit 20 includes a compressor 21 for compressing the refrigerant, an indoor condenser 22, an outdoor condenser 23, a chiller expansion valve 24, a cooling expansion valve 25, a cooling evaporator 26, an accumulator 27, and refrigerant piping 28. The refrigerant piping 28 is a component for connecting each of the devices 21, 22, 23, 24, 25, 26, and 27, and is provided between each of the devices 21, 22, 23, 24, 25, 26, and 27, so the refrigerant circuit 20 has multiple refrigerant pipes 28. In Figure 2, to avoid clutter on the drawing, not all of the refrigerant pipes are labeled, but only one of them is labeled.

[0033] The compressor 21, although not shown in the figure, is an electric compressor equipped with an electric motor and a compression mechanism operated by the electric motor. As shown in Figure 1, the compressor 21 is connected to a control unit 600, and the control unit 600 controls the switching between ON and OFF states and the rotational speed when ON. The compressor 21 operates by a combination of control based on the requirements of the air conditioning system, the cooling requirements of the battery B, and the cooling requirements of the drive unit E.

[0034] The indoor condenser 22 is connected to the refrigerant discharge port (not shown) of the compressor 21 via refrigerant piping 28, and is a heat exchanger into which the high-temperature, high-pressure refrigerant compressed by the compressor 21 flows. The indoor condenser 22 is installed inside the vehicle cabin and is a device for heating the vehicle cabin. The vehicle cabin is the space in which the occupants are seated.

[0035] The outdoor condenser 23 is connected to the refrigerant outlet (not shown) of the indoor condenser 22 via refrigerant piping 28 and is a heat exchanger into which the refrigerant that has flowed through the indoor condenser 22, i.e., the refrigerant compressed by the compressor 21, flows. The outdoor condenser 23 is located outside the vehicle. Outside the vehicle is a space outside the space where the occupants are seated, where heat exchange with the outside air is possible. Examples of areas outside the vehicle include the motor room (not shown) where the front motor MA and rear motor MB are housed, and the front of the vehicle (for example, inside the front grille).

[0036] The electric vehicle 1 of this embodiment is equipped with a grill shutter GS. The grill shutter GS is a device for opening and closing the opening of the front grill (not shown), and has a grill shutter actuator GS1 as shown in Figure 1. The grill shutter actuator GS1 is connected to a control unit 600, which controls the operation of the grill shutter GS from an open state to a closed state and from a closed state to an open state. When the outdoor condenser 23 is located inside the front grill, closing the grill shutter GS reduces the amount of outside air flowing into the outdoor condenser 23, and opening the grill shutter GS increases the amount of outside air flowing into the outdoor condenser 23.

[0037] The cooling evaporator 26 is installed inside the vehicle cabin and is a device for cooling the cabin or dehumidifying the air supplied to the cabin. The refrigerant outlet (not shown) of the outdoor condenser 23 and the refrigerant inlet (not shown) of the cooling evaporator 26 are connected by refrigerant piping 28. Between the outdoor condenser 23 and the cooling evaporator 26 in the refrigerant piping 28, there is a cooling expansion valve 25 that expands the refrigerant flowing out from the outdoor condenser 23. The refrigerant expanded by the cooling expansion valve 25 flows into the cooling evaporator 26. The cooling expansion valve 25 is connected to a control unit 600, and the opening degree can be changed by the control unit 600.

[0038] The refrigerant piping 28 includes chiller piping 28a extending to the chiller 30. The chiller 30 is a heat exchanger connected between the chiller expansion valve 24 and the compressor 21, and is configured to exchange heat with a heat transfer medium, which will be described later. The chiller 30 is located away from the outdoor condenser 23 and the radiator 301.

[0039] Chiller piping 28a branches off from the refrigerant piping 28 upstream of the cooling expansion valve 25, and refrigerant flowing out from the outdoor condenser 23 flows into chiller piping 28a. Chiller piping 28a is equipped with a chiller expansion valve 24 that expands the refrigerant flowing out from the outdoor condenser 23. The refrigerant inlet (not shown) of chiller 30 is connected downstream of the chiller expansion valve 24 in chiller piping 28a. Therefore, refrigerant expanded by the chiller expansion valve 24 flows into chiller 30.

[0040] The downstream side of the chiller piping 28a is connected to the refrigerant inlet (not shown) of the accumulator 27. The refrigerant outlet of the cooling evaporator 26 is also connected to the refrigerant inlet of the accumulator 27. The accumulator 27 performs gas-liquid separation of the refrigerant that flows in through the chiller 30 and / or the cooling evaporator 26. The liquid refrigerant outlet (not shown) of the accumulator 27 is connected to the refrigerant suction port (not shown) of the compressor 21.

[0041] The refrigerant circuit 20 is provided with a check valve 20a between the outdoor condenser 23 and the chiller expansion valve 24 and the cooling expansion valve 25. This check valve 20a prevents the backflow of refrigerant from the chiller expansion valve 24 and cooling expansion valve 25 to the outdoor condenser 23.

[0042] The refrigerant circuit 20 is provided with a check valve 20b between the cooling evaporator 26 and the chiller 30 and accumulator 27. This check valve 20b prevents the backflow of refrigerant from the chiller 30 and accumulator 27 to the cooling evaporator 26.

[0043] The refrigerant circuit 20 includes an indoor two-way valve 20c and an outdoor two-way valve 20d. The indoor two-way valve 20c and the outdoor two-way valve 20d are composed of, for example, solenoid valves and are connected to a control unit 600, so that their opening and closing operations are controlled by the control unit 600. The indoor two-way valve 20c is installed between the indoor condenser 22 and the cooling evaporator 26. When opened by the control unit 600, the refrigerant flowing out of the indoor condenser 22 flows into the chiller expansion valve 24 and the cooling expansion valve 25. When closed by the control unit 600, the refrigerant flowing out of the indoor condenser 22 does not flow into the chiller expansion valve 24 and the cooling expansion valve 25. In other words, the indoor two-way valve 20c controls the flow of refrigerant to the cooling evaporator 26 and the chiller 30.

[0044] The outdoor two-way valve 20d is installed between the indoor condenser 22 and the outdoor condenser 23. When opened by the control unit 600, refrigerant flowing out of the indoor condenser 22 flows into the outdoor condenser 23. Conversely, when closed by the control unit 600, refrigerant flowing out of the indoor condenser 22 is prevented from flowing into the outdoor condenser 23. In other words, the outdoor two-way valve 20d controls the flow of refrigerant to the outdoor condenser 23.

[0045] The refrigerant circuit 20 includes a high-pressure side refrigerant pressure sensor 20A, a high-pressure side refrigerant temperature sensor 20B, a cooling side refrigerant temperature sensor 20C, and a chiller side refrigerant temperature sensor 20D. The high-pressure side refrigerant pressure sensor 20A is located downstream of the indoor condenser 22 and the outdoor condenser 23, and upstream of the chiller expansion valve 24 and the cooling expansion valve 25, and acquires the pressure of the refrigerant flowing through that location. The refrigerant pressure acquired by the high-pressure side refrigerant pressure sensor 20A is output to the control unit 600.

[0046] The high-pressure refrigerant temperature sensor 20B is located downstream of the indoor condenser 22 and the outdoor condenser 23, and upstream of the chiller expansion valve 24 and the cooling expansion valve 25, and acquires the temperature of the refrigerant flowing through that location. The refrigerant temperature acquired by the high-pressure refrigerant temperature sensor 20B is output to the control unit 600.

[0047] The cooling-side refrigerant temperature sensor 20C is installed between the cooling evaporator 26 and the check valve 20b, and acquires the temperature of the refrigerant flowing through that point. In other words, the cooling-side refrigerant temperature sensor 20C acquires the temperature of the refrigerant after it has flowed out of the cooling evaporator 26. The refrigerant temperature acquired by the cooling-side refrigerant temperature sensor 20C is output to the control unit 600.

[0048] The chiller-side refrigerant temperature sensor 20D is installed between the chiller 30 and the accumulator 27, and acquires the temperature of the refrigerant flowing through that point. In other words, the chiller-side refrigerant temperature sensor 20D acquires the temperature of the refrigerant after it has flowed out of the chiller 30. The refrigerant temperature acquired by the chiller-side refrigerant temperature sensor 20D is output to the control unit 600.

[0049] The indoor condenser 22 and the cooling evaporator 26 constitute part of the vehicle air conditioning system 40. The vehicle air conditioning system 40 also includes an indoor electric heater 41 and a blower motor 42 (shown in Figure 1). The blower motor 42 is a device for blowing outside air and / or inside air to the indoor condenser 22, the cooling evaporator 26, and the indoor electric heater 41. The indoor electric heater 41 and the blower motor 42 are connected to and controlled by a control unit 600.

[0050] The vehicle air conditioning system 40 is equipped with an air mix actuator 43 (shown in Figure 1) that operates an air mix damper (not shown). The air mix actuator 43 is connected to a control unit 600 and controlled by the control unit 600. By operating the air mix damper, the air mix actuator 43 makes it possible to adjust the temperature of the air conditioning supplied to the vehicle cabin.

[0051] In other words, in the vehicle air conditioning system 40, the entire amount of air blown by the blower motor 42 is sent to the cooling evaporator 26. Basically, during cooling operation, the air mix actuator 43 operates the air mix damper so that the entire amount of air that has passed through the cooling evaporator 26 is supplied to the vehicle interior without passing through the interior condenser 22 and the interior electric heater 41.

[0052] On the other hand, during heating operation, the air mix actuator 43 operates the air mix damper so that a portion or all of the air that has passed through the cooling evaporator 26 is supplied to the indoor condenser 22 and indoor electric heater 41, heated, and then supplied to the passenger compartment.

[0053] The control unit 600 determines how much air from the air that has passed through the cooling evaporator 26 should be supplied to the interior condenser 22 and interior electric heater 41, according to the target temperature inside the vehicle cabin, and controls the air mix actuator 43 so that that amount of air is supplied to the interior condenser 22 and interior electric heater 41. The interior electric heater 41 has a heating element that generates heat when power is supplied, such as a PTC element. The interior electric heater 41 may be provided as needed.

[0054] (Configuration of the first circuit) The first circuit 100 is a circuit for regulating the temperature of battery B, and can also be called a temperature regulation circuit for battery B. The first circuit 100 includes a coolant heater 101 and a first coolant pipe 102.

[0055] The coolant heater 101 is an electric heater controlled by the control unit 600, and has a heating element that generates heat when power is supplied, such as a PTC element. When the temperature of battery B is too low to be suitable for charging and discharging, the control unit 600 activates the coolant heater 101 to heat the coolant. When the temperature of battery B is within the temperature range suitable for charging and discharging, or when the temperature of battery B exceeds the temperature range suitable for charging and discharging, the control unit 600 stops the coolant heater 101.

[0056] The first coolant pipe 102 is a pipe for circulating coolant fluid within the first circuit 100 via an eight-way valve 500. The upstream and downstream ends of the first coolant pipe 102 are connected to the connection ports of the eight-way valve 500. A coolant heater 101 is provided upstream of the first coolant pipe 102. A battery B is provided downstream of the coolant heater 101 in the first coolant pipe 102.

[0057] A heat exchanger (not shown) is provided in a portion of the first coolant piping 102, and this heat exchanger is positioned to be in contact with the outer surface of the battery B. Heat exchange takes place between the coolant liquid circulating inside the heat exchanger and the battery B. When the temperature of the battery B is higher than the temperature of the coolant liquid, the battery B is cooled, and conversely, when the temperature of the battery B is lower than the temperature of the coolant liquid, the battery B is heated.

[0058] The first circuit 100 is equipped with a heater temperature sensor 101a and a battery temperature sensor 100a. The heater temperature sensor 101a is a sensor for acquiring the temperature of the coolant heater 101. The heater temperature acquired by the heater temperature sensor 101a is output to the control unit 600.

[0059] The battery temperature sensor 100a is a sensor for obtaining the temperature of battery B. The battery temperature sensor 100a may obtain the temperature of battery B by, for example, obtaining the temperature of the cell surface or the vicinity of the cells of battery B, or by obtaining the temperature of the coolant fluid in the vicinity of battery B. The position and location of the battery temperature sensor 100a are not particularly limited. The information regarding the temperature of battery B obtained by the battery temperature sensor 100a is output to the control unit 600.

[0060] (2nd circuit) The second circuit 200 is a circuit for controlling the temperature of the drive unit E, and can also be called, for example, a temperature control circuit for the drive unit E. The second circuit 200 includes a first coolant pump 201, a separation tank 202, and a second coolant pipe 203.

[0061] The second coolant pipe 203 is a pipe for circulating coolant liquid within the second circuit 200 via an eight-way valve 500. The upstream and downstream ends of the second coolant pipe 203 are connected to the connection ports of the eight-way valve 500. The first coolant pump 201 is located upstream of the second coolant pipe 203 and sends the coolant liquid in the second coolant pipe 203 downstream, creating a circulating flow. A drive unit E is located downstream of the first coolant pump 201 in the second coolant pipe 203. The drive unit E is a cooling target device that is cooled by the coolant liquid flowing through the second circuit 200.

[0062] The order in which coolant is supplied to the front motor MA, rear motor MB, front inverter IA, rear inverter IB, charge controller C, and power supply D included in the drive unit E is not particularly limited, but in this embodiment, the second coolant piping 203 is configured so that the coolant is supplied in the following order. That is, the front inverter IA, charge controller C, power supply D, rear inverter IB, rear motor MB, and front motor MA are connected in series in the second coolant piping 203 in the order from the upstream side to the downstream side in the direction of coolant flow. For example, the front motor MA and rear motor MB may be water-cooled, which are cooled directly with coolant, or they may be oil-cooled, which are cooled by circulating oil. In the case of oil cooling, the oil temperature can be lowered by exchanging heat between the oil and the coolant.

[0063] The front inverter IA, charge controller C, power supply D, rear inverter IB, etc., may also be oil-cooled or water-cooled. In the case of water cooling, the front inverter IA, charge controller C, power supply D, rear inverter IB, etc., can be cooled using a heat exchange structure (not shown) provided in a part of the second coolant piping 203. That is, although the structure is not particularly limited, the front inverter IA, charge controller C, power supply D, and rear inverter IB can be cooled by heat exchange between the coolant liquid flowing through the heat exchange structure of the second coolant piping 203 and the front inverter IA, charge controller C, power supply D, and rear inverter IB.

[0064] The separation tank 202 is located downstream of the drive unit E in the second coolant piping 203. After passing through the drive unit E, the coolant flows into the separation tank 202 and then to the 8-way valve 500. Although not shown in the figure, the separation tank 202 is connected to a reserve tank where the coolant is stored.

[0065] The second circuit 200 is equipped with a coolant temperature sensor 200a. The coolant temperature sensor 200a is a sensor for obtaining the temperature of the coolant liquid in the second coolant piping 203. The coolant temperature sensor 200a is located between the first coolant pump 201 and the drive unit E.

[0066] A drive unit temperature sensor may be configured using the coolant temperature sensor 200a to acquire the temperature of the drive unit E. For example, by having the coolant temperature sensor 200a acquire the temperature of the coolant fluid flowing through the second circuit 200, the inlet temperature of the drive unit E, i.e., the temperature of the drive unit E, can be acquired. In addition, the thermal management system S may have a drive unit temperature sensor that acquires the temperature of the drive unit E separately from the coolant temperature sensor 200a. For example, a temperature sensor that acquires the temperature of relatively heat-sensitive equipment such as the front inverter IA and the rear inverter IB can be provided and used as the drive unit temperature sensor. Thus, the location and position of the drive unit temperature sensor are not particularly limited. The following describes the case where the coolant temperature sensor 200a is used as the drive unit temperature sensor. The information regarding the temperature of the drive unit E acquired by the coolant temperature sensor 200a is output to the control unit 600.

[0067] (3rd circuit) The third circuit 300 includes a radiator 301 for dissipating the heat of the coolant to the outside air, as well as a third coolant pipe 302 and an electric fan 303. The radiator 301, like the outdoor condenser 23, is located outside the vehicle. In this embodiment, the outdoor condenser 23 is located inside the front grille to ensure sufficient ventilation, and the radiator 301 is positioned behind the outdoor condenser 23 (downstream in the direction of outside airflow) located inside the front grille. The outdoor condenser 23 and the radiator 301 may be modularized in a stacked state in the direction of outside airflow, or the outdoor condenser 23 and the radiator 301 may be mounted separately on the vehicle body. In any case, the positional relationship between the outdoor condenser 23 and the radiator 301 is set so that outside air that has passed through the outdoor condenser 23 is introduced into the radiator 301.

[0068] The third coolant pipe 302 is a pipe for circulating coolant fluid within the third circuit 300 via the eight-way valve 500. The upstream and downstream ends of the third coolant pipe 302 are connected to the connection ports of the eight-way valve 500.

[0069] The electric fan 303 is a device for supplying outside air to the radiator 301 and is installed, for example, inside the front grille. When the electric fan 303 is activated, the control unit 600 controls the grille shutter actuator GS1 to open the grille shutter GS.

[0070] The direction of the outside airflow formed by the electric fan 303 is from the front to the rear of the vehicle. This direction of outside airflow is the same as the direction of outside airflow when the electric vehicle 1 is in motion. Since the outdoor condenser 23 is located in front of the radiator 301, the outside air flows through the outdoor condenser 23 via the flow formed by the electric fan 303 before flowing into the radiator 301. The same outside airflow occurs when the electric vehicle 1 is in motion. The electric fan 303 is connected to the control unit 600, and the control unit 600 switches it ON and OFF and controls its rotation speed when ON according to the heat dissipation requirement. The electric fan 303 operates not only to send outside air to the radiator 301, but also when the refrigerant circuit 20 is operating, sending outside air to the outdoor condenser 23. Therefore, it can be said that the electric fan 303 also constitutes a part of the refrigerant circuit 20.

[0071] (4th circuit) The fourth circuit 400 is a circuit for cooling the coolant liquid with the chiller 30, and can also be called a coolant liquid cooling circuit. The fourth circuit 400 comprises a second coolant pump 401 and a fourth coolant pipe 402. The fourth coolant pipe 402 is a pipe for circulating the coolant liquid within the fourth circuit 400 via an eight-way valve 500. The upstream and downstream ends of the fourth coolant pipe 402 are connected to the connection ports of the eight-way valve 500.

[0072] The second coolant pump 401 is located in the fourth coolant piping 402 and sends the coolant liquid in the fourth coolant piping 402 downstream, creating a circulating flow. A chiller 30 is located upstream of the second coolant pump 401 in the fourth coolant piping 402.

[0073] The chiller 30 is provided with a refrigerant flow path through which the refrigerant supplied by the chiller piping 28a of the refrigerant circuit 20 flows, and a coolant flow path through which the coolant supplied by the fourth coolant piping 402 flows. The refrigerant flowing through the refrigerant flow path and the coolant flowing through the coolant flow path are capable of heat exchange, and when the temperature of the coolant is higher than the temperature of the refrigerant, the coolant can be cooled.

[0074] The fourth circuit 400 is equipped with a chiller temperature sensor 400a. The chiller temperature sensor 400a is a sensor for obtaining the temperature of the coolant liquid after it has been cooled by the chiller 30. The temperature of the coolant liquid obtained by the chiller temperature sensor 400a is output to the control unit 600. The fourth coolant pipe 402 of the fourth circuit 400 is connected to a reserve tank (not shown).

[0075] (Control unit) The control unit 600 includes, for example, a microcomputer containing a central processing unit, ROM (Read Only Memory), RAM (Random Access Memory), various signal processing units, input / output interfaces, etc. A program is stored in the memory unit (not shown) of the control unit 600, and the central processing unit performs various processes and controls as described below in accordance with the program.

[0076] The control unit 600 includes a part for controlling the vehicle air conditioning system 40, a part for controlling the first circuit 100, the second circuit 200, the third circuit 300, and the fourth circuit 400, and a part for controlling the 8-way valve 500. These can be configured as a combination of hardware and software, or as hardware only.

[0077] The part for controlling the vehicle air conditioning system 40, the part for controlling the first circuit 100, the second circuit 200, the third circuit 300, the fourth circuit 400, and the part for controlling the 8-way valve 500 may be physically separate. Alternatively, the part for controlling the vehicle air conditioning system 40, the part for controlling the first circuit 100, the second circuit 200, the third circuit 300, the fourth circuit 400, and the part for controlling the 8-way valve 500 may be integrated. Furthermore, the control unit 600 may include a part for controlling the vehicle's drive system E. Thus, the configuration of the control unit 600 is not particularly limited, and it may be configured to integrate and control in-vehicle equipment and devices. For example, it can be configured to acquire vehicle speed information, thereby enabling control based on vehicle speed.

[0078] The control unit 600 is connected to an outside air temperature sensor 601 that acquires the outside air temperature, and the outside air temperature acquired by the outside air temperature sensor 601 (acquired outside air temperature) is input to the control unit 600. The outside air temperature sensor 601 is a component of the thermal management system S. The location of the outside air temperature sensor 601 is not particularly limited, but for example, it can be located on the upstream side in the direction of outside air flow in the front grille. In addition, although not shown in the figures, an interior air temperature sensor that acquires the temperature inside the vehicle, an operation panel for adjusting the set temperature of the air conditioning, etc., are also connected to the control unit 600.

[0079] Furthermore, the 8-way valve 500 is a device for connecting or disconnecting two or more of the first circuit 100, second circuit 200, third circuit 300, and fourth circuit 400, and is controlled by the control unit 600 as described below. Note that the connection and disconnection of the first circuit 100, second circuit 200, third circuit 300, and fourth circuit 400 shown below is just one example, and other connections and disconnections can also be performed.

[0080] (Specific control by the control unit) The control unit 600 controls the refrigerant circuit 20 and the vehicle air conditioning system 40 when air conditioning the vehicle interior. In heating operation, the control unit 600 operates the compressor 21 of the refrigerant circuit 20 to supply high-temperature, high-pressure refrigerant to the interior condenser 22, causing it to condense and thus turning the interior condenser 22 into an air heater. The control unit 600 operates the interior electric heater 41 as needed, as well as the blower motor 42 of the vehicle air conditioning system 40, and further controls the air mix actuator 43 to operate the air mix damper so that conditioned air at the target temperature is obtained. The obtained conditioned air is supplied to various parts of the vehicle interior.

[0081] As shown in Figure 3, in cooling operation to cool the vehicle interior, the control unit 600 operates the compressor 21 of the refrigerant circuit 20 to supply high-temperature, high-pressure refrigerant to the indoor condenser 22 and outdoor condenser 23 for condensation. Then, the two-layer gas-liquid refrigerant, expanded by the cooling expansion valve 25, is supplied to the cooling evaporator 26 for evaporation, thereby turning the cooling evaporator 26 into an air cooler. The control unit 600 operates the blower motor 42 of the vehicle air conditioning system 40 and further controls the air mix actuator 43 to operate the air mix damper so that conditioned air at the target temperature is obtained. In Figure 3, the areas where refrigerant flows are shown with black fill, and the areas where coolant liquid flows are shown with hatched lines. If cooling of the vehicle interior is not required, the blower motor 42 can be stopped. This will almost completely eliminate heat absorption by the cooling evaporator 26.

[0082] During the first cooling operation shown in Figure 3, when cooling the battery B and the drive unit E, the control unit 600 controls the 8-way valve 500 to connect the first coolant pipe 102 of the first circuit 100 to the fourth coolant pipe 402 of the fourth circuit 400, and also connects the upstream and downstream ends of the second coolant pipe 203 of the second circuit 200. At this time, the 8-way valve 500 disconnects the third circuit 300 from the first circuit 100, the second circuit 200, and the fourth circuit 400. The circuit formed in this way is called the first cooling operation circuit. Because the third circuit 300 is disconnected from the first circuit 100, the second circuit 200, and the fourth circuit 400, the coolant liquid from the third circuit 300 does not flow into the first circuit 100, the second circuit 200, and the fourth circuit 400.

[0083] The connection and disconnection of the first circuit 100, second circuit 200, third circuit 300, and fourth circuit 400 is made possible by the shape and position of the connection passages formed inside the eight-way valve 500. The eight-way valve 500 is just one example of a configuration for connecting and disconnecting the first circuit 100, second circuit 200, third circuit 300, and fourth circuit 400, and the connection and disconnection of the first circuit 100, second circuit 200, third circuit 300, and fourth circuit 400 may also be performed using a switching structure other than the eight-way valve 500.

[0084] The control unit 600 then activates the second coolant pump 401. When the second coolant pump 401 is activated, the first coolant pipe 102 of the first circuit 100 and the fourth coolant pipe 402 of the fourth circuit 400 are connected, so the coolant flows from the second coolant pump 401 in order to the 8-way valve 500, the first coolant pipe 102, the coolant heater 101, the battery B, the 8-way valve 500, the fourth coolant pipe 402, and the chiller 30, and is then drawn into the second coolant pump 401. The coolant heater 101 is not activated because the battery B is being cooled. As the coolant passes through the chiller 30, it is cooled by heat exchange with the refrigerant in the chiller 30, and the cooled coolant can be supplied to the battery B, thus cooling the battery B. Also, as the coolant passes through the chiller 30, the refrigerant in the chiller 30 is heated, so the heat from the battery B can be used to heat the interior of the vehicle. The rotational speed of the second coolant pump 401 should be set according to the cooling requirements of battery B.

[0085] Meanwhile, in the second circuit 200, the control unit 600 operates the first coolant pump 201. When the first coolant pump 201 is operated, the coolant liquid in the second circuit 200 flows through the second coolant piping 203, passes through the front inverter IA, charge controller C, power supply D, rear inverter IB, rear motor MB, and front motor MA of the drive unit E, flows into the separation tank 202, and is then drawn into the first coolant pump 201 via the 8-way valve 500. The rotational speed of the first coolant pump 201 can be set according to the cooling requirements of the drive unit E.

[0086] If only battery B needs cooling and drive unit E does not, the first coolant pump 201 may be stopped to halt the flow of coolant in the second circuit 200. Even if only battery B needs cooling and drive unit E does not, the first coolant pump 201 may be operated to allow coolant to flow in the second circuit 200 in order to cool the control unit 600.

[0087] For example, when battery B generates a large amount of heat, such as during rapid charging of battery B, the chiller 30 absorbs more heat from the refrigerant, resulting in increased heat dissipation from the outdoor condenser 23. When the amount of heat dissipated from the outdoor condenser 23 increases, there is a risk that the heat released from the outdoor condenser 23 will be absorbed by the radiator 301, which is located downstream of the outdoor condenser 23 in the direction of outside airflow. When heat is absorbed by the radiator 301, the temperature of the coolant rises, and if it is connected to the second circuit 200 at this time, the drive unit E may not be able to be cooled, raising concerns that a malfunction may occur in the drive unit E.

[0088] In the first cooling operation of this embodiment, the third circuit 300, which has a radiator 301, is disconnected from the second circuit 200 for cooling the drive unit E. Therefore, even if a large amount of heat is dissipated from the outdoor condenser 23, the heat released from the outdoor condenser 23 does not affect the temperature of the coolant in the second circuit 200 for cooling the drive unit E. As a result, the drive unit E can be cooled by the second circuit 200.

[0089] Furthermore, since the circulation of coolant in the third circuit 300 is stopped, the coolant, whose temperature has risen due to the radiator 301 absorbing heat released from the outdoor condenser 23, is less likely to flow to the 8-way valve 500. As a result, the coolant, whose temperature has risen in the radiator 301, does not heat the coolant in the first circuit 100 via the 8-way valve 500, thereby improving the cooling performance of battery B.

[0090] In operation using the first cooling circuit, the coolant in the second circuit 200 circulates only within the second circuit 200, so no active heat dissipation occurs from the coolant in the second circuit 200. When the amount of heat dissipated by the drive unit E is small, operation using the first cooling circuit is not a problem. However, when the amount of heat dissipated by the drive unit E increases, it may become difficult to cool the drive unit E when operating using the first cooling circuit.

[0091] In such cases, as shown in Figure 4, the control unit 600 switches from the first cooling operation to the second cooling operation. When cooling the battery B and the drive unit E during the second cooling operation, the control unit 600 controls the 8-way valve 500 to connect the first coolant pipe 102 of the first circuit 100 to the fourth coolant pipe 402 of the fourth circuit 400, and also connects the second coolant pipe 203 of the second circuit 200 to the third coolant pipe 302 of the third circuit 300. The first circuit 100 and the fourth circuit 400 are separated from the second circuit 200 and the third circuit 300. The circuit formed in this way is called the second cooling operation circuit.

[0092] The control unit 600 then operates the second coolant pump 401 to circulate the coolant liquid to the first circuit 100 and the fourth circuit 400 as described above. The control unit 600 also operates the first coolant pump 201. When the first coolant pump 201 is operated, the coolant liquid flows from the first coolant pump 201 in order to the drive unit E, separation tank 202, 8-way valve 500, third coolant pipe 302, radiator 301, 8-way valve 500, second coolant pipe 203, and is drawn into the first coolant pump 201. During the second cooling operation, the refrigerant in the chiller 30 is heated as the coolant liquid passes through the chiller 30, so the heat from the battery B can be used to heat the vehicle interior.

[0093] Switching to the second cooling operation circuit enables cooling of the drive unit E using the radiator 301. However, as mentioned above, if the amount of heat dissipated from the outdoor condenser 23 is large, it may become difficult to cool the drive unit E. To address this, the control unit 600 of this embodiment is configured to perform heat absorption suppression control, which suppresses the absorption of heat released from the outdoor condenser 23 of the refrigerant circuit 20 by the radiator 301 of the third circuit 300.

[0094] In other words, as shown in Figure 4, the control unit 600 switches to the second cooling operation circuit to perform battery cooling by connecting the first circuit 100 and the fourth circuit 400, and drive unit cooling by connecting the second circuit 200 and the third circuit 300. The control unit 600 performs heat absorption suppression control while performing battery cooling and drive unit cooling. The specific control will be described later, but for example, in the heat absorption suppression control, the control unit 600 performs control to restrict the chiller expansion valve 24 compared to before the heat absorption suppression control was performed. By restricting the chiller expansion valve 24, the amount of refrigerant passing through the chiller 30 is reduced, and the amount of heat absorbed by the refrigerant per unit time can be reduced. As a result, the amount of heat dissipated from the outdoor condenser 23 is reduced, and the heat released from the outdoor condenser 23 is less likely to be absorbed by the radiator 301. In this way, the opening degree of the chiller expansion valve 24 is controlled so that the heat dissipation to the outside air from the outdoor condenser 23 does not obstruct the heat dissipation to the outside air from the radiator 301. In the heat absorption suppression control, the chiller expansion valve 24 may be closed.

[0095] The heat absorption suppression control is not limited to controlling the opening degree of the chiller expansion valve 24, but may also be controlled by controlling the opening degree of the cooling expansion valve 25. For example, the control unit 600 performs heat absorption suppression control when the vehicle interior is being cooled by the refrigerant circuit 20. During cooling operation, the refrigerant that has passed through the cooling expansion valve 25 flows into the cooling evaporator 26, so the refrigerant absorbs heat in the cooling evaporator 26.

[0096] In this heat absorption suppression control during cooling operation, the control unit 600 restricts the cooling expansion valve 25 compared to before the heat absorption suppression control was executed. By restricting the cooling expansion valve 25, the amount of refrigerant passing through the cooling evaporator 26 is reduced, thereby lowering the amount of heat absorbed by the refrigerant per unit time. As a result, the amount of heat dissipated from the outdoor condenser 23 decreases, and the heat released from the outdoor condenser 23 is less likely to be absorbed by the radiator 301. In the heat absorption suppression control, control to close the cooling expansion valve 25 may also be performed.

[0097] The heat absorption suppression control is not limited to controlling the opening of the chiller expansion valve 24 and the cooling expansion valve 25, but may also be a control that reduces the amount of air supplied to the cooling evaporator 26, for example. During cooling operation, air is supplied to the cooling evaporator 26 by the rotation of the blower motor 42. However, if the amount of air supplied to the cooling evaporator 26 is large, the amount of heat absorbed by the refrigerant per unit time in the cooling evaporator 26 increases. Therefore, when the control unit 600 performs heat absorption suppression control during cooling operation of the vehicle interior by the refrigerant circuit 20, it performs a control that reduces the rotation speed of the blower motor 42 compared to before the heat absorption suppression control was performed.

[0098] This reduces the amount of air blown to the cooling evaporator 26, thereby reducing the amount of heat absorbed by the refrigerant per unit time. As a result, the amount of heat dissipated from the outdoor condenser 23 decreases, and the heat released from the outdoor condenser 23 is less likely to be absorbed by the radiator 301. In the heat absorption suppression control, the rotation speed of the blower motor 42 may be set to 0, i.e., the blower motor 42 may be stopped.

[0099] The heat absorption suppression control may also be a control that reduces the amount of coolant supplied by the second coolant pump 401 of the fourth circuit 400. For example, in the heat absorption suppression control, the control unit 600 executes a control that reduces the amount supplied by the second coolant pump 401 compared to before the heat absorption suppression control was executed. As a result, the amount of coolant passing through the chiller 30 per unit time decreases, and the amount of heat absorbed by the refrigerant in the chiller 30 can be reduced. As a result, the amount of heat dissipated from the outdoor condenser 23 decreases, and the heat released from the outdoor condenser 23 is less likely to be absorbed by the radiator 301.

[0100] The heat absorption suppression control may also be a control that reduces the rotational speed of the compressor 21 of the refrigerant circuit 20. For example, in the heat absorption suppression control, the control unit 600 performs a control that reduces the rotational speed of the compressor 21 compared to before the heat absorption suppression control was performed. As a result, the amount of refrigerant passing through the chiller 30 and the cooling evaporator 26 per unit time is reduced, so the amount of heat absorbed by the chiller 30 and the cooling evaporator 26 of the refrigerant can be reduced. As a result, the amount of heat dissipated from the outdoor condenser 23 is reduced, and the heat released from the outdoor condenser 23 is less likely to be absorbed by the radiator 301.

[0101] The heat absorption suppression control may also be the operation control of the air mix damper of the vehicle air conditioning system 40. For example, when the vehicle air conditioning system 40 is operating, the control unit 600 may control the air mix actuator 43 to operate the air mix damper so that the amount of air supplied to the indoor condenser 22 of the refrigerant circuit 20 is greater than before the heat absorption suppression control was performed. When the amount of air supplied to the indoor condenser 22 is increased, the amount of heat dissipated from the indoor condenser 22 increases, which reduces the amount of heat dissipated from the outdoor condenser 23, making it less likely for the heat released from the outdoor condenser 23 to be absorbed by the radiator 301. This control may be limited to, for example, heating. In addition, the rotational speed of the blower motor 42 may be increased along with the control of the air mix actuator 43.

[0102] In the heat absorption suppression control, any one of the following controls may be executed: control of the opening degree of the chiller expansion valve 24, control of the opening degree of the cooling expansion valve 25, control of the blower motor 42, control of the second coolant pump 401, control of the compressor 21, and control of the air mix actuator 43. Alternatively, any two or more controls may be executed in combination. When two or more controls are executed in combination, they may be executed simultaneously, or an execution order may be set and executed sequentially according to that order. Furthermore, it may be possible to determine whether the vehicle air conditioning system 40 is operating in cooling mode or heating mode, and enable control of the opening degree of the cooling expansion valve 25 only when operating in cooling mode.

[0103] A specific example of control by the control unit 600 will be explained based on the flowchart shown in Figure 5 and the timing chart shown in Figure 6. The flowchart shown in Figure 5 starts, for example, when the power to the electric vehicle 1 is turned ON, or when external charging of the battery B begins, even if the power to the electric vehicle 1 is not turned ON. Step SA1 after the start proceeds if the temperature of the battery B (hereinafter simply referred to as the temperature of battery B) obtained by the battery temperature sensor 100a is equal to or greater than the cooling start temperature. In this flowchart, 52°C is given as an example of the cooling start temperature, but it is not limited to this.

[0104] Step SA2 proceeds if the ambient temperature obtained by the ambient temperature sensor 601 is 10°C or higher. Since cooling of the battery B and drive unit E by the ambient air is not expected to be significant when the ambient temperature is 10°C or higher, the process proceeds to step SA3, where the control unit 600 sets the circuit of the thermal management system S to the first cooling circuit shown in Figure 3 and performs a first cooling operation that can cool the battery B and drive unit E.

[0105] In step SA4, the control unit 600 determines whether the temperature of battery B exceeds the cooling completion temperature. The cooling completion temperature is set to a temperature lower than the cooling start temperature. In this flowchart, 47°C is given as an example of the cooling completion temperature, but it is not limited to this. If step SA4 determines No and the temperature of battery B is below the cooling completion temperature, then cooling of battery B is not necessary, and this flowchart is terminated. If the temperature of battery B exceeds the cooling completion temperature, it is considered to be above the temperature at which cooling is required.

[0106] If step SA4 is determined to be Yes and the temperature of battery B exceeds the cooling completion temperature, proceed to step SA5. In step SA5, it is determined whether the inlet temperature of the drive unit E, obtained by the coolant temperature sensor 200a, is in a high-temperature state. In this flowchart, 63°C is given as the temperature used for the determination in step SA5, but it is not limited to this, and can be any temperature below the temperature at which damage to the thermally weakest component of the drive unit E can be suppressed, and above the temperature at which cooling is required.

[0107] If step SA5 is determined to be Yes and the inlet temperature of the drive unit E obtained by the coolant temperature sensor 200a is high, the process proceeds to step SA6, where the control unit 600 sets the circuit of the thermal management system S to the second cooling circuit shown in Figure 4, executes the second cooling operation, and performs heat absorption suppression control.

[0108] In this way, in step SA5, the control unit 600 determines whether the temperature of the drive unit E obtained by the coolant temperature sensor 200a is 63°C or higher (example of the first temperature), and if it is determined that the temperature of the drive unit E obtained by the coolant temperature sensor 200a is 63°C or higher, it executes heat absorption suppression control in step SA6.

[0109] Furthermore, in step SA4, the control unit 600 determines whether the temperature of battery B, as obtained by the battery temperature sensor 100a, is above the temperature requiring cooling (second temperature). If it is determined that the temperature of battery B, as obtained by the battery temperature sensor 100a, is above the temperature requiring cooling, the control unit 600 executes heat absorption suppression control in step SA6. The temperature used in the determination in step SA5 is set higher than the temperature used in the determination in step SA4. In this embodiment, the control unit 600 executes heat absorption suppression control not only when it is determined that the temperature of the drive unit E, as obtained by the coolant temperature sensor 200a, is 63°C or higher, but also when it is determined that the temperature of battery B, as obtained by the battery temperature sensor 100a, is above the temperature requiring cooling.

[0110] Note that the temperature used in the determination of step SA5 and the temperature used in the determination of step SA4 may be the same, or the temperature used in the determination of step SA5 may be set lower than the temperature used in the determination of step SA4.

[0111] As shown in Figure 6, when the temperature of the drive unit E rises and reaches a high temperature state, it switches from the first cooling operation to the second cooling operation and performs heat absorption suppression control, so the amount of heat dissipated by the outdoor condenser 23 decreases.

[0112] In step SA7 of the flowchart shown in Figure 5, the control unit 600 determines whether the inlet temperature of the drive unit E, as obtained by the coolant temperature sensor 200a, is higher than 58°C. The temperature used in the determination in step SA7 is set lower than the temperature used in the determination in step SA5, and the difference can be, for example, between 3 and 7°C. If step SA7 is determined to be No and the inlet temperature of the drive unit E is 58°C or lower, the process returns to step SA4. On the other hand, if step SA7 is determined to be Yes and the inlet temperature of the drive unit E is higher than 58°C, the process proceeds to step SA8.

[0113] In step SA8, the control unit 600 determines whether the temperature of battery B is higher than 60°C. The temperature used in the determination in step SA8 is set higher than the temperatures used in the determinations in steps SA1 and SA4. If step SA8 determines No and the temperature of battery B is 60°C or lower, the process returns to step SA4. On the other hand, if step SA7 determines Yes and the temperature of battery B is higher than 60°C, the process proceeds to step SA9. Similarly, if step SA5 determines No, the process also proceeds to step SA9.

[0114] In step SA9, the control unit 600 determines whether the inlet temperature of the drive unit E is in the range of 58°C to 63°C. If the determination in step SA9 is Yes and the inlet temperature of the drive unit E is in the range of 58°C to 63°C, the process proceeds to step SA10. On the other hand, if the determination in step SA9 is No and the inlet temperature of the drive unit E is not in the range of 58°C to 63°C, the process proceeds to step SA11.

[0115] In step SA10, the cooling expansion valve 25 is throttled as a heat absorption suppression control. That is, if the inlet temperature of the drive unit E is high and the temperature of the battery B is high even after throttling the chiller expansion valve 24 in step SA6, the cooling expansion valve 25 is throttled to suppress heat absorption in the cooling evaporator 26 and increase the cooling capacity of the drive unit E and the battery B.

[0116] Thus, after executing control to throttle the chiller expansion valve 24, the control unit 600 determines whether the temperature of the drive unit E obtained by the coolant temperature sensor 200a exceeds 58°C (example of the third temperature). If it is determined that the temperature of the drive unit E obtained by the coolant temperature sensor 200a exceeds 58°C during cooling operation, it executes both control to throttle the chiller expansion valve 24 and control to throttle the cooling expansion valve 25.

[0117] In step SA11, since the inlet temperature of the drive unit E is higher than in step SA10, in addition to throttling the cooling expansion valve 25 as a heat absorption suppression control, the rotational speed of the compressor 21 is reduced. This reduces both the amount of heat absorbed by the cooling evaporator 26 and the amount of heat absorbed by the chiller 30, thereby further increasing the cooling capacity of the drive unit E and battery B.

[0118] Thus, in step SA9, the control unit 600 determines whether the temperature of the drive unit E acquired by the coolant temperature sensor 200a during cooling operation exceeds 63°C (an example of a fourth temperature higher than the third temperature). If it is determined that the temperature of the drive unit E acquired by the coolant temperature sensor 200a during cooling operation exceeds 63°C, the control unit 600 performs a control in the heat absorption suppression control that reduces the rotational speed of the compressor 21 compared to before the heat absorption suppression control was performed.

[0119] Figure 7 shows the flow of refrigerant and coolant liquid when cooling battery B and drive unit E during the third cooling operation. The third cooling operation is performed when there is a cooling request for battery B and the ambient temperature is below 10°C, regardless of the air conditioning state or driving state. Although Figure 7 shows the state in which refrigerant is flowing in the refrigerant circuit 20, the state of refrigerant flow in the refrigerant circuit 20 can be any, as the air conditioning state is irrelevant. In addition, although not shown, the control unit 600 can also acquire information that the user has operated a preconditioning switch, for example, and if the ambient temperature is below 10°C and there is a cooling request for battery B, the third cooling operation can be performed. Furthermore, the third cooling operation can also be performed when there is a cooling request for battery B during external charging.

[0120] During the third cooling operation, when cooling the battery B and the drive unit E, the control unit 600 controls the 8-way valve 500 to connect the first coolant pipe 102 of the first circuit 100, the second coolant pipe 203 of the second circuit 200, the third coolant pipe 302 of the third circuit 300, and the fourth coolant pipe 402 of the fourth circuit 400. The circuit formed by this is called the third cooling operation circuit.

[0121] The control unit 600 then activates the first coolant pump 201 and / or the second coolant pump 401. When the first coolant pump 201 and / or the second coolant pump 401 are activated, the coolant flows in the following order from the radiator 301: 8-way valve 500, first coolant pump 201, drive unit E, separation tank 202, 8-way valve 500, coolant heater 101, battery B, 8-way valve 500, chiller 30, second coolant pump 401, 8-way valve 500, and finally back to the radiator 301.

[0122] In the third cooling operation circuit, the coolant is cooled by the chiller 30 and then dissipated to the outside air via the radiator 301 before being used to cool the drive unit E and battery B. When the vehicle air conditioning system 40 is operating in heating mode, the refrigerant in the refrigerant circuit 20 can utilize the heat absorbed by the chiller 30 to improve the heating efficiency inside the vehicle.

[0123] The embodiments described above are merely illustrative in all respects and should not be interpreted restrictively. Furthermore, any modifications or changes that fall within the equivalent scope of the claims are all within the scope of the present invention. [Industrial applicability]

[0124] As explained above, the vehicle thermal management system described herein can be used, for example, in electric vehicles. [Explanation of Symbols]

[0125] 1 Electric vehicle 20 Refrigerant Circuit 21 Compressor 22 Indoor capacitors 23 Outdoor condenser 24 Chiller expansion valve 25 Cooling Expansion Valve 26. Evaporator for air conditioning 30 Chiller 100 1st circuit 100A Battery Temperature Sensor 200 2nd circuit 200a Coolant Temperature Sensor (Drive Unit Temperature Sensor) 300 3rd circuit 301 Radiator 400 4th circuit 600 control unit B Battery E Drive Unit S Thermal Management System

Claims

1. A vehicle thermal management system installed in a vehicle that runs by supplying power from a battery to a drive unit, A refrigerant circuit having a compressor for compressing the refrigerant, an outdoor condenser into which the refrigerant compressed by the compressor flows, and a chiller expansion valve for expanding the refrigerant that has flowed out of the outdoor condenser, A chiller connected between the chiller expansion valve and the compressor of the refrigerant circuit, A first circuit is configured to allow the flow of a heat transfer medium, and the temperature of the battery is adjusted by the flowing heat transfer medium. A second circuit is configured to allow the flow of the heat transfer medium and to adjust the temperature of the drive device using the flowing heat transfer medium, A third circuit having a radiator configured to allow the circulation of the heat transfer medium and to exchange heat between the circulating heat transfer medium and the outside air, A fourth circuit is configured to allow the flow of the heat transfer medium and is connected to the chiller, A vehicle thermal management system comprising a control unit that performs battery cooling by connecting the first circuit and the fourth circuit, and drive unit cooling by connecting the second circuit and the third circuit, and performs heat absorption suppression control to suppress the absorption of heat released from the outdoor condenser into the radiator during the execution of the battery cooling and the drive unit cooling.

2. In the vehicle thermal management system according to claim 1, The drive device temperature sensor further provides the temperature of the drive device, The control unit determines whether the temperature of the drive unit obtained by the drive unit temperature sensor is equal to or greater than a first temperature, and if it is determined that the temperature of the drive unit obtained by the drive unit temperature sensor is equal to or greater than the first temperature, it executes the heat absorption suppression control, a thermal management system for vehicles.

3. In the vehicle thermal management system according to claim 2, The system further includes a battery temperature sensor that acquires the temperature of the aforementioned battery, The control unit determines whether the battery temperature obtained by the battery temperature sensor is equal to or greater than a second temperature, and if it is determined that the battery temperature obtained by the battery temperature sensor is equal to or greater than the second temperature, it executes the heat absorption suppression control, thereby providing a thermal management system for vehicles.

4. In the vehicle thermal management system according to claim 3, A vehicle thermal management system in which the first temperature is set higher than the second temperature.

5. In the vehicle thermal management system according to claim 4, The control unit is a vehicle thermal management system that executes the heat absorption suppression control when it is determined that the temperature of the drive unit, as obtained by the drive unit temperature sensor, is equal to or greater than the first temperature, and the temperature of the battery, as obtained by the battery temperature sensor, is equal to or greater than the second temperature.

6. In the vehicle thermal management system according to claim 5, In the heat absorption suppression control described above, the control unit executes a control that throttles the chiller expansion valve compared to before the heat absorption suppression control was executed, in a vehicle thermal management system.

7. In the vehicle thermal management system according to claim 6, The refrigerant circuit includes a cooling expansion valve that expands the refrigerant flowing out from the outdoor condenser, and a cooling evaporator into which the refrigerant expanded by the cooling expansion valve flows. The control unit performs the heat absorption suppression control when the vehicle interior is being cooled by the refrigerant circuit, and in the heat absorption suppression control during the cooling operation, the cooling expansion valve is throttled compared to before the heat absorption suppression control was performed, in a vehicle thermal management system.

8. In the vehicle thermal management system according to claim 7, The control unit, after executing control to throttle the chiller expansion valve, determines whether the temperature of the drive unit obtained by the drive unit temperature sensor exceeds a third temperature, and if it is determined that the temperature of the drive unit obtained by the drive unit temperature sensor during cooling operation exceeds the third temperature, executes both control to throttle the chiller expansion valve and control to throttle the cooling expansion valve, in a vehicle thermal management system.

9. In the vehicle thermal management system according to claim 8, A vehicle thermal management system comprising: a control unit that determines whether the temperature of the drive unit obtained by the drive unit temperature sensor during the cooling operation exceeds a fourth temperature higher than the third temperature, and if it is determined that the temperature of the drive unit obtained by the drive unit temperature sensor during the cooling operation exceeds the fourth temperature, the control unit executes a control in the heat absorption suppression control that reduces the rotational speed of the compressor compared to before the heat absorption suppression control was executed.

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