Multi-domain coupled thermal management system for electric vehicle based on transcritical co2 cycle

Abstract

The application discloses a multi-domain coupled thermal management system of an electric vehicle based on a transcritical CO2 cycle and relates to the technical field of power battery thermal management. The thermal management system comprises a refrigerant circuit, a battery pack cooling liquid circuit, a motor cooling liquid circuit and an electric control unit, the electric control unit is connected with each circuit respectively, the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit are connected through the communication position change of a plurality of valves, and a cooling process, a heat supply process and a waste heat utilization process are formed. Through the coupling design of the refrigerant circuit and the battery pack and the motor double cooling liquid circuits, the application realizes the all-domain multi-mode temperature control collaborative management of the passenger compartment, the battery and the motor, can match the extreme working condition requirements from low-temperature cold start to high-temperature fast charging, and further builds a multi-stage waste heat recovery system for improving the comprehensive utilization efficiency of waste heat and further relieving the problem of the endurance attenuation of the electric vehicle in a low-temperature environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power battery thermal management, and particularly relates to a multi-domain coupled thermal management system for electric vehicles based on transcritical CO2 cycle. BACKGROUND

[0002] The current electric vehicle thermal management system faces multiple technical challenges. First, the traditional refrigerant R134a faces environmental regulation restrictions due to high global warming potential (GWP), and new alternative refrigerants have application bottlenecks. Hydrofluoroalkene working fluids (such as R1234yf) have a risk of flammability; natural working fluid CO2 has environmental advantages of zero ozone depletion potential (ODP) and extremely low GWP, but the transcritical cycle under dynamic working conditions of electric vehicles has not yet broken through the energy efficiency optimization, especially in low temperature environments, the heating energy consumption is high and the efficiency is low, resulting in insufficient heating capacity, which seriously affects the driving range. Secondly, the existing thermal management system mostly adopts a separate architecture, with the cabin air conditioner, battery temperature control and motor cooling subsystems running independently, which not only causes component redundancy, but also leads to low energy utilization efficiency. In low temperature environments, there is a competition for heat sources between battery preheating and cabin heating, and the comprehensive utilization rate of waste heat is insufficient. More importantly, the waste heat of the motor system is not effectively utilized, and the temperature level of the heat source is seriously mismatched with the demand grade of the heat utilization end, resulting in energy waste.

[0003] Therefore, it is urgent to design an electric vehicle thermal management system that can not only be compatible with environmentally friendly working fluids, but also realize multi-domain heat source coupling and energy grade matching, so as to break through the energy efficiency bottleneck and improve the driving performance of the whole vehicle. SUMMARY

[0004] In view of the above problems that the current power battery thermal management has high heating energy consumption, low efficiency and low waste heat utilization rate in low temperature environments, and affects the driving range, the present application provides a multi-domain coupled thermal management system for electric vehicles based on transcritical CO2 cycle.

[0005] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0006] The application discloses a multi-domain coupled thermal management system for an electric vehicle based on a transcritical CO2 cycle, which comprises a refrigerant circuit, a battery pack cooling liquid circuit, a motor cooling liquid circuit and an electronic control unit, the electronic control unit is connected with each circuit, the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit are connected through the communication position change of a plurality of valves to form a cooling process, a heating process and a waste heat utilization process. The refrigerant circuit comprises an electric compressor, a four-way reversing valve, a gas-liquid separator, a first electronic expansion valve, a second electronic expansion valve, a second heat exchanger, a third heat exchanger, an AB passage of a fourth heat exchanger, an AB passage of a fifth heat exchanger and a sixth heat exchanger, a first three-way valve, a third three-way valve, a fourth three-way valve, a fifth three-way valve, a sixth three-way valve and a seventh three-way valve, the outlet of the electric compressor is connected with the B end of the four-way reversing valve, and each component is connected. The battery pack cooling liquid circuit comprises a battery pack liquid cooling plate, a first water pump and a CD passage of the fourth heat exchanger, and each component is connected. The motor cooling liquid circuit comprises a motor water jacket, a second water pump, a second three-way valve, an eighth three-way valve, a CD passage of the first heat exchanger and the sixth heat exchanger, and each component is connected. Carbon dioxide is used as the refrigerant in the refrigerant circuit, and the battery pack cooling liquid circuit and the motor cooling liquid circuit both use water-glycol-based cooling liquid.

[0007] Further, in the refrigerant circuit, the inlet of the electric compressor is connected with the outlet of the gas-liquid separator, the outlet is connected with the B port of the four-way reversing valve; the A port of the four-way reversing valve is connected with the C port of the third three-way valve, the C port is connected with the A port of the seventh three-way valve, the D port is connected with the B port of the third heat exchanger; the A port of the third three-way valve is connected with the B port of the second heat exchanger, the B port is connected with the A port of the fourth three-way valve; the A port of the first three-way valve is connected with the A port of the sixth three-way valve, the B port is connected with the A port of the second heat exchanger, the C port is connected with the C port of the third heat exchanger; the B port of the fourth three-way valve is connected with the B port of the fifth three-way valve, the C port is connected with the A port of the fourth heat exchanger through the first electronic expansion valve; the A port of the fifth three-way valve is connected with the D port of the third heat exchanger, the C port is connected with the B port of the fifth heat exchanger through the second electronic expansion valve; the B port of the sixth three-way valve is connected with the C port of the seventh three-way valve, the C port is connected with the B port of the fourth heat exchanger; the A port of the sixth heat exchanger is connected with the B port of the seventh three-way valve, the B port is connected with the A port of the fifth heat exchanger; the inlet of the gas-liquid separator is connected with the A port of the third heat exchanger. In the battery pack cooling liquid circuit, the inlet of the battery pack liquid cooling plate is connected with the outlet of the first water pump, the outlet is connected with the C port of the fourth heat exchanger; the inlet of the first water pump is connected with the D port of the fourth heat exchanger. In the motor cooling liquid circuit, the inlet of the motor water jacket is connected with the B port of the eighth three-way valve, the outlet is connected with the inlet of the second water pump; the outlet of the second water pump is connected with the B port of the second three-way valve; the A port of the second three-way valve is connected with the B port of the first heat exchanger, the C port of the second three-way valve is connected with the C port of the sixth heat exchanger; the D port of the sixth heat exchanger is connected with the C port of the eighth three-way valve; the A port of the first heat exchanger is connected with the A port of the eighth three-way valve.

[0008] Further, the electric control unit is connected with the electric compressor, the first water pump, the second water pump, the air blower, the first three-way valve, the second three-way valve, the third three-way valve, the fourth three-way valve, the fifth three-way valve, the sixth three-way valve, the seventh three-way valve, the eighth three-way valve, the four-way reversing valve, the first electronic expansion valve and the second electronic expansion valve respectively, for controlling the on-off of the electric compressor, the first water pump, the second water pump and the air blower, and the connection position of the ports in each valve.

[0009] Further, the first heat exchanger is a finned tube heat exchanger for heat exchange between the motor coolant and air; the second heat exchanger and the fifth heat exchanger are both finned tube heat exchangers for heat exchange between the refrigerant and air; the third heat exchanger is a double-pipe heat exchanger having two passages AB and CD, and the refrigerant in the two passages AB and CD can exchange heat; the fourth heat exchanger is a plate heat exchanger, in which AB is a refrigerant passage and CD is a battery pack coolant passage, and the fourth heat exchanger is used for heat exchange between the refrigerant and the battery pack coolant; and the sixth heat exchanger is a three-medium heat exchanger having three passages AB, CD and air, in which AB is a refrigerant passage and CD is a motor coolant passage, and the sixth heat exchanger has fins on the outside for heat exchange with air, and is used for heat exchange between the refrigerant and the motor coolant or between the motor coolant and air.

[0010] Further, the cooling process includes a first mode, a second mode, a third mode and a fourth mode.

[0011] If the temperature of the power battery exceeds the appropriate temperature range, the first mode is automatically entered, the first mode cooperates the battery pack coolant circuit with the refrigerant circuit to transfer the heat of the power battery to the outside to realize cooling of the power battery; the electric control unit controls the electric compressor to start, the four-way reversing valve is switched to the AB connection and CD connection position, the first three-way valve is switched to the BC separate connection position, the third three-way valve is switched to the AC separate connection position, the fourth three-way valve is switched to the BC separate connection position, the fifth three-way valve is switched to the AB separate connection position, the sixth three-way valve is switched to the BC separate connection position, and the seventh three-way valve is switched to the AC separate connection position.

[0012] If the passenger compartment refrigeration function is turned on, the second mode is automatically entered, the second mode circulates the refrigerant in the refrigerant circuit to transfer the heat of the passenger compartment to the outside to realize cooling of the passenger compartment; the electric control unit controls the electric compressor and the air blower to start, the four-way reversing valve is switched to the AB connection and CD connection position, the first three-way valve is switched to the BC separate connection position, the third three-way valve is switched to the AC separate connection position, the fifth three-way valve is switched to the AC separate connection position, and the seventh three-way valve is switched to the AB separate connection position.

[0013] If the temperature of the power battery exceeds the appropriate temperature range and the user turns on the passenger cabin refrigeration function, the third mode is automatically entered, the third mode cooperates the battery pack cooling liquid circuit with the refrigerant circuit to transfer the heat of the passenger cabin and the power battery to the outside, and realizes the synchronous cooling of the passenger cabin and the power battery; the electric control unit controls the electric compressor, the air blower and the first water pump to be turned on, the four-way reversing valve is switched to the AB connection and CD connection position, the first three-way valve is switched to the BC separate connection position, the third three-way valve is switched to the AC separate connection position, the fourth three-way valve is switched to the BC separate connection position, the fifth three-way valve is switched to the AB connection and AC connection position, the sixth three-way valve is switched to the BC separate connection position, and the seventh three-way valve is switched to the AB connection and AC separate connection position.

[0014] If the temperature of the power battery and the motor both exceed the appropriate temperature range, and the passenger cabin refrigeration function is turned on, the fourth mode is automatically entered, the fourth mode cooperates the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit to transfer the heat of the passenger cabin, the power battery and the motor to the outside, and realizes cooling; the electric control unit controls the electric compressor, the air blower, the first water pump and the second water pump to be turned on, the four-way reversing valve is switched to the AB connection and CD connection position, the first three-way valve is switched to the BC separate connection position, the second three-way valve is switched to the AB separate connection position, the third three-way valve is switched to the AC separate connection position, the fourth three-way valve is switched to the BC separate connection position, the fifth three-way valve is switched to the AB connection and AC connection position, the sixth three-way valve is switched to the BC separate connection position, the seventh three-way valve is switched to the AB connection and AC separate connection position, and the eighth three-way valve is switched to the AB separate connection position.

[0015] Further, the heating process includes a fifth mode, a sixth mode and a seventh mode;

[0016] If the temperature of the power battery is lower than the appropriate temperature range, the fifth mode is automatically entered, the fifth mode cooperates the refrigerant circuit and the battery pack cooling liquid circuit to transfer the heat of the outside to the power battery, and realizes the heating of the power battery; the electric control unit controls the electric compressor and the first water pump to be turned on, the four-way reversing valve is switched to the AD connection and BC connection position, the first three-way valve is switched to the BC separate connection position, the third three-way valve is switched to the AC separate connection position, the fourth three-way valve is switched to the BC separate connection position, the fifth three-way valve is switched to the AB separate connection position, the sixth three-way valve is switched to the BC separate connection position, and the seventh three-way valve is switched to the AC separate connection position.

[0017] If the passenger cabin heating function is turned on, the sixth mode is automatically entered, the sixth mode transmits external heat to the passenger cabin through the circulation of refrigerant in the refrigerant circuit to realize heating of the passenger cabin; the electric control unit controls the electric compressor and the air blower to be turned on, the four-way reversing valve is switched to the AD connection and BC connection position, the first three-way valve is switched to the BC separate connection position, the third three-way valve is switched to the AC separate connection position, the fifth three-way valve is switched to the AC separate connection position, and the seventh three-way valve is switched to the AB separate connection position.

[0018] If the temperature of the power battery is lower than the suitable temperature range and the passenger cabin heating function is turned on, the seventh mode is automatically entered, the seventh mode transmits external heat to the passenger cabin and the power battery through the cooperation of the refrigerant circuit and the battery pack cooling liquid circuit to realize synchronous heating of the power battery and the passenger cabin; the electric control unit controls the electric compressor, the air blower and the first water pump to be turned on, the four-way reversing valve is switched to the AD connection and BC connection position, the first three-way valve is switched to the BC separate connection position, the third three-way valve is switched to the AC separate connection position, the fourth three-way valve is switched to the BC separate connection position, the fifth three-way valve is switched to the AB connection and AC connection position, the sixth three-way valve is switched to the BC separate connection position, and the seventh three-way valve is switched to the AB connection and AC connection position.

[0019] Further, the waste heat utilization process includes an eighth mode, a ninth mode, a tenth mode and an eleventh mode.

[0020] If the temperature of the power battery is lower than the suitable temperature range and the temperature of the motor is higher than the minimum temperature thereof, the eighth mode is automatically entered, the eighth mode transmits motor heat to the power battery through the cooperation of the battery pack cooling liquid circuit, the motor cooling liquid circuit and the refrigerant circuit to realize heating of the power battery; the electric control unit commands the electric compressor, the first water pump and the second water pump to be started, the first electronic expansion valve is in the full open position, the four-way reversing valve is switched to the AB connection and CD connection position, the first three-way valve is switched to the AC separate connection position, the second three-way valve is switched to the BC separate connection position, the third three-way valve is switched to the BC separate connection position, the fourth three-way valve is switched to the AC separate connection position, the fifth three-way valve is switched to the AC separate connection position, the sixth three-way valve is switched to the AC separate connection position, the seventh three-way valve is switched to the AB separate connection position, and the eighth three-way valve is switched to the BC separate connection position.

[0021] If the temperature of the power battery is lower than the suitable temperature range, the passenger compartment opens the heating function, and the temperature of the motor is higher than the suitable temperature range, the ninth mode is automatically entered, the ninth mode cooperates the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit to transfer the heat of the outside and the motor to the power battery and the passenger compartment, and synchronous heating of the power battery and the passenger compartment is realized; the electric control unit controls the electric compressor, the air blower, the first water pump and the second water pump to be opened, the four-way reversing valve is switched to the AD communication and BC communication position, the first three-way valve is switched to the BC separate communication position, the second three-way valve is switched to the BC separate communication position, the third three-way valve is switched to the AC separate communication position, the fourth three-way valve is switched to the BC separate communication position, the fifth three-way valve is switched to the AB communication and AC communication position, the sixth three-way valve is switched to the BC separate communication position, the seventh three-way valve is switched to the AB communication and AC communication position, and the eighth three-way valve is switched to the BC separate communication position.

[0022] If the temperature of the power battery exceeds the suitable temperature range and the passenger compartment opens the heating function, the tenth mode is automatically entered, the tenth mode cooperates the refrigerant circuit and the battery pack cooling liquid circuit to transfer the heat of the outside and the battery pack to the passenger compartment, and heating of the passenger compartment is realized; the electric control unit controls the electric compressor, the air blower and the first water pump to be opened, the first electronic expansion valve is in the full open position, the four-way reversing valve is switched to the AD communication and BC communication position, the first three-way valve is switched to the AC communication and BC communication position, the third three-way valve is switched to the AC communication and BC communication position, the fourth three-way valve is switched to the AC separate communication position, the fifth three-way valve is switched to the AC separate communication position, the sixth three-way valve is switched to the AC separate communication position, and the seventh three-way valve is switched to the AB separate communication position.

[0023] If the temperature of the power battery exceeds the suitable temperature range, the passenger compartment opens the heating function, and the temperature of the motor exceeds the suitable temperature range, the eleventh mode is automatically entered, the eleventh mode cooperates the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit to transfer the heat of the outside, the power battery and the motor to the passenger compartment, and heating of the passenger compartment is realized; the electric control unit controls the electric compressor, the air blower, the first water pump and the second water pump to be opened, the first electronic expansion valve is in the full open position, the four-way reversing valve is switched to the AD communication and BC communication position, the first three-way valve is switched to the AC communication and BC communication position, the second three-way valve is switched to the BC separate communication position, the third three-way valve is switched to the AC communication and BC communication position, the fourth three-way valve is switched to the AC separate communication position, the fifth three-way valve is switched to the AC separate communication position, the sixth three-way valve is switched to the AC separate communication position, the seventh three-way valve is switched to the AB separate communication position, and the eighth three-way valve is switched to the BC separate communication position.

[0024] Further, the waste heat utilization process further comprises a twelfth mode and a thirteenth mode.

[0025] If the passenger compartment opens the heating function and the temperature of the motor water jacket outlet is greater than 80 DEG C, then automatically enter the twelfth mode, the twelfth mode is through the circulation of the cooling liquid in the motor cooling liquid circuit, the heat of the motor is transmitted to the passenger compartment, and the heating of the passenger compartment is realized; the electric control unit controls the second water pump to open, the second three-way valve is switched to the BC separate communication position, and the eighth three-way valve is switched to the BC separate communication position.

[0026] If the passenger compartment opens the heating function, the temperature of the motor water jacket outlet is greater than 80 DEG C, and the temperature of the power battery exceeds the appropriate temperature range, then automatically enter the thirteenth mode, the thirteenth mode is through the cooperation of the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit, the heat of the motor is transmitted to the passenger compartment, the heating of the passenger compartment is realized, the energy consumption of the passenger compartment heating is reduced, and the power battery is cooled by the environment outside the vehicle; the electric control unit controls the electric compressor, the air blower, the first water pump and the second water pump to open, the four-way reversing valve is switched to the AB communication and CD communication position, the first three-way valve is switched to the BC separate communication position, the second three-way valve is switched to the BC separate communication position, the third three-way valve is switched to the AC separate communication position, the fourth three-way valve is switched to the BC separate communication position, the fifth three-way valve is switched to the AB separate communication position, the sixth three-way valve is switched to the BC separate communication position, the seventh three-way valve is switched to the AC separate communication position, and the eighth three-way valve is switched to the BC separate communication position.

[0027] The beneficial effects of the present application are: 1, the present application adopts CO2 refrigerant instead of freon working medium, which can avoid the high GWP environmental risk of traditional refrigerant, and also can significantly exert the low temperature heating advantage of transcritical CO2 cycle, and compared with R134a system, the low temperature working condition heating capacity is significantly improved, and the system energy efficiency is improved. 2, compared with the traditional independent subsystem architecture, by adopting the coupling design of the refrigerant circuit and the battery pack and the motor double cooling liquid circuit, and integrating the intelligent electric control unit, the global multi-mode temperature control collaborative management of the passenger compartment, the battery and the motor is realized, and through the architecture integration, the number of components can be effectively reduced, the system redundancy can be reduced, and the extreme working condition demand from low temperature cold start to high temperature fast charging can be accurately matched, which provides a high reliable solution for the full climate thermal management of the electric vehicle power battery. 3, the present application is aimed at the heat generation characteristic difference of the motor and the power battery, a multi-stage waste heat recovery system is constructed, high-grade waste heat is preferentially used for passenger compartment heating, and medium and low temperature waste heat is gradually supplied to the transcritical CO2 cycle to realize passenger compartment heating, which greatly improves the comprehensive utilization efficiency of waste heat, further alleviates the range attenuation problem in low temperature environment, and provides a systematic solution for the energy efficiency improvement of electric vehicles. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Fig. 1 shows a schematic diagram of the structure principle of an embodiment of the present application.

[0029] Figure 2 Fig. 2 shows a schematic diagram of the working principle of the first mode.

[0030] Figure 3 Fig. 3 shows a schematic diagram of the working principle of the second mode.

[0031] Figure 4 Fig. 4 shows a schematic diagram of the working principle of the third mode.

[0032] Figure 5 Fig. 5 shows a schematic diagram of the working principle of the fourth mode.

[0033] Figure 6 Fig. 6 shows a schematic diagram of the working principle of the fifth mode.

[0034] Figure 7 Fig. 7 shows a schematic diagram of the working principle of the sixth mode.

[0035] Figure 8 Fig. 8 shows a schematic diagram of the working principle of the seventh mode.

[0036] Figure 9 Fig. 9 shows a schematic diagram of the working principle of the eighth mode.

[0037] Figure 10 Fig. 10 shows a schematic diagram of the working principle of the ninth mode.

[0038] Figure 11 Fig. 11 shows a schematic diagram of the working principle of the tenth mode.

[0039] Figure 12 Fig. 12 shows a schematic diagram of the working principle of the eleventh mode.

[0040] Figure 13 Fig. 13 shows a schematic diagram of the working principle of the twelfth mode.

[0041] Figure 14 Fig. 14 shows a schematic diagram of the working principle of the thirteenth mode.

[0042] BRIEF DESCRIPTION OF THE DRAWINGS 1, first three-way valve; 2, first heat exchanger; 3, second heat exchanger; 4, second three-way valve; 5, third three-way valve; 6, gas-liquid separator; 7, electric compressor; 8, third heat exchanger; 9, four-way reversing valve; 10, fourth three-way valve; 11, fifth three-way valve; 12, first electronic expansion valve; 13, fourth heat exchanger; 14, battery pack liquid cooling plate; 15, first water pump; 16, sixth three-way valve; 17, seventh three-way valve; 18, second electronic expansion valve; 19, air blower; 20, fifth heat exchanger; 21, air conditioning box; 22, sixth heat exchanger; 23, second water pump; 24, motor water jacket; 25, eighth three-way valve. DETAILED DESCRIPTION

[0043] This invention discloses a multi-domain coupled thermal management system for electric vehicles based on a transcritical CO2 cycle, applicable to, but not limited to, electric vehicles, where the power battery is configured within the battery pack. An embodiment of this invention is described in detail below with reference to the accompanying drawings.

[0044] like Figure 1 As shown, the thermal management system includes a refrigerant circuit, a battery pack coolant circuit, a motor coolant circuit, and an electronic control unit. The electronic control unit is connected to each circuit. The refrigerant circuit, battery pack coolant circuit, and motor coolant circuit are connected by several valves, and the connection positions of these valves change to form a cooling process, a heating process, and a waste heat utilization process.

[0045] The refrigerant circuit includes an electric compressor 7, a four-way reversing valve 9, a gas-liquid separator 6, a first electronic expansion valve 12, a second electronic expansion valve 18, a second heat exchanger 3, a third heat exchanger 8, an AB passage of a fourth heat exchanger 13, an AB passage of a fifth heat exchanger 20 and a sixth heat exchanger 22, a first three-way valve 1, a third three-way valve 5, a fourth three-way valve 10, a fifth three-way valve 11, a sixth three-way valve 16, and a seventh three-way valve 17. The outlet of the electric compressor 7 is connected to the B end of the four-way reversing valve 9, and all components are connected.

[0046] The battery pack coolant circuit includes the CD passage of the battery pack liquid cooling plate 14, the first water pump 15 and the fourth heat exchanger 13, and the components are connected.

[0047] The motor coolant circuit includes the motor water jacket 24, the second water pump 23, the second three-way valve 4, the eighth three-way valve 25, the first heat exchanger 2, and the CD passage of the sixth heat exchanger 22, with each component connected.

[0048] Carbon dioxide refrigerant is used in the refrigerant circuit, while water-ethylene glycol coolant is used in both the battery pack coolant circuit and the motor coolant circuit.

[0049] The electronic control unit is connected to the electric compressor 7, the first water pump 15, the second water pump 23, the blower 19, the first three-way valve 1, the second three-way valve 4, the third three-way valve 5, the fourth three-way valve 10, the fifth three-way valve 11, the sixth three-way valve 16, the seventh three-way valve 17, the eighth three-way valve 25, the four-way reversing valve 9, the first electronic expansion valve 12, and the second electronic expansion valve 18, respectively, and is used to control the switching of the electric compressor 7, the first water pump 15, the second water pump 23, and the blower 19, as well as the connection position of the ports in each valve.

[0050] The four-way directional valve 9 has four ports: A, B, C, and D. It can switch between two positions: either AB is connected and CD is connected, or AD is connected and BC is connected.

[0051] The first three-way valve 1 has three ports A, B and C, and can switch three positions, which are AC separate communication position, or BC separate communication position, or AC communication and BC communication position.

[0052] The second three-way valve 4 has three ports A, B and C, and can switch two positions, which are AB separate communication position, or BC separate communication position.

[0053] The third three-way valve 5 has three ports A, B and C, and can switch three positions, which are AC separate communication position, or BC separate communication position, or AC communication and BC communication position.

[0054] The fourth three-way valve 10 has three ports A, B and C, and can switch two positions, which are AC separate communication position, or BC separate communication position.

[0055] The fifth three-way valve 11 has three ports A, B and C, and can switch three positions, which are AB separate communication position, or AC separate communication position, or AB communication and AC communication position.

[0056] The sixth three-way valve 16 has three ports A, B and C, and can switch two positions, which are AC separate communication position, or BC separate communication position.

[0057] The seventh three-way valve 17 has three ports A, B and C, and can switch three positions, which are AB separate communication position, or AC separate communication position, or AB communication and AC communication position.

[0058] The eighth three-way valve 25 has three ports A, B and C, and can switch two positions, which are AB separate communication position, or BC separate communication position.

[0059] The first heat exchanger 2 is a finned tube heat exchanger, which is used for heat exchange between the motor coolant and air; the second heat exchanger 3 and the fifth heat exchanger 20 are both finned tube heat exchangers, which are used for heat exchange between the refrigerant and air; the third heat exchanger 8 is a double-pipe heat exchanger, which has two passages AB and CD, and the refrigerants in the two passages AB and CD can exchange heat; the fourth heat exchanger 13 is a plate heat exchanger, which has AB as a refrigerant passage and CD as a battery pack coolant passage, and is used for heat exchange between the refrigerant and the battery pack coolant; the sixth heat exchanger 22 is a three-medium heat exchanger, which has three passages AB, CD and air, and AB is a refrigerant passage and CD is a motor coolant passage, and the sixth heat exchanger 22 has fins outside for air heat exchange, and is used for heat exchange between the refrigerant and the motor coolant or between the motor coolant and air.

[0060] The outlet of the electric compressor 7 is connected with the B port of the four-way reversing valve 9.

[0061] The B port of the four-way reversing valve 9 is connected with the outlet of the electric compressor 7; the A port of the four-way reversing valve 9 is connected with the C port of the third three-way valve 5; the C port of the four-way reversing valve 9 is connected with the A port of the seventh three-way valve 17; the D port of the four-way reversing valve 9 is connected with the B port of the third heat exchanger 8.

[0062] The A port of the first three-way valve 1 is connected with the A port of the sixth three-way valve 16, the B port of the first three-way valve 1 is connected with the A end of the second heat exchanger 3, and the C port of the first three-way valve 1 is connected with the C end of the third heat exchanger 8.

[0063] The A port of the second three-way valve 4 is connected with the B port of the first heat exchanger 2, the B port of the second three-way valve 4 is connected with the outlet of the second water pump 23, and the C port of the second three-way valve 4 is connected with the C port of the sixth heat exchanger 22.

[0064] The A port of the third three-way valve 5 is connected with the B port of the second heat exchanger 3, the B port of the third three-way valve 5 is connected with the A port of the fourth three-way valve 10, and the C port of the third three-way valve 5 is connected with the A port of the four-way reversing valve 9.

[0065] The A port of the fourth three-way valve 10 is connected with the B port of the third three-way valve 5, the B port of the fourth three-way valve 10 is connected with the B port of the fifth three-way valve 11, and the C port of the fourth three-way valve 10 is connected with the A port of the fourth heat exchanger 13 through the first electronic expansion valve 12.

[0066] The A port of the fifth three-way valve 11 is connected with the D port of the third heat exchanger 8, the B port of the fifth three-way valve 11 is connected with the B port of the fourth three-way valve 10, and the C port of the fifth three-way valve 11 is connected with the B port of the fifth heat exchanger 20 through the second electronic expansion valve 18.

[0067] The A port of the sixth three-way valve 16 is connected with the A port of the first three-way valve 1, the B port of the sixth three-way valve 16 is connected with the C port of the seventh three-way valve 17, and the C port of the sixth three-way valve 16 is connected with the B port of the fourth heat exchanger 13.

[0068] The A port of the seventh three-way valve 17 is connected with the C port of the four-way reversing valve 9, the B port of the seventh three-way valve 17 is connected with the A port of the sixth heat exchanger 22, and the C port of the seventh three-way valve 17 is connected with the B port of the sixth three-way valve 16.

[0069] The A port of the eighth three-way valve 25 is connected with the A port of the first heat exchanger 2, the B port of the eighth three-way valve 25 is connected with the inlet of the motor water jacket 24, and the C port of the eighth three-way valve 25 is connected with the D port of the sixth heat exchanger 22.

[0070] The A port of the first heat exchanger 2 is connected with the A port of the eighth three-way valve 25, and the B port of the first heat exchanger 2 is connected with the A port of the second three-way valve 4.

[0071] The A port of the second heat exchanger 3 is connected with the B port of the first three-way valve 1, and the B port of the second heat exchanger 3 is connected with the A port of the third three-way valve 5.

[0072] The A port of the third heat exchanger 8 is connected with the inlet of the gas-liquid separator 6, the B port of the third heat exchanger 8 is connected with the D port of the four-way reversing valve 9, the C port of the third heat exchanger 8 is connected with the C port of the first three-way valve 1, and the D port of the third heat exchanger 8 is connected with the A port of the fifth three-way valve 11.

[0073] The A port of the fourth heat exchanger 13 is connected with the C port of the fourth three-way valve 10 through the first electronic expansion valve 12, the B port of the fourth heat exchanger 13 is connected with the C port of the sixth three-way valve 16, the C port of the fourth heat exchanger 13 is connected with the outlet of the battery pack liquid cooling plate 14, and the D port of the fourth heat exchanger 13 is connected with the inlet of the first water pump 15.

[0074] The A port of the fifth heat exchanger 20 is connected with the B port of the sixth heat exchanger 22, and the B port of the fifth heat exchanger 20 is connected with the C port of the fifth three-way valve 11 through the second electronic expansion valve 18.

[0075] The A port of the sixth heat exchanger 22 is connected with the B port of the seventh three-way valve 17, the B port of the sixth heat exchanger 22 is connected with the A port of the fifth heat exchanger 20, the C port of the sixth heat exchanger 22 is connected with the C port of the second three-way valve 4, and the D port of the sixth heat exchanger 22 is connected with the C port of the eighth three-way valve 25.

[0076] The inlet of the first water pump 15 is connected with the D port of the fourth heat exchanger 13, and the outlet of the first water pump 15 is connected with the inlet of the battery pack liquid cooling plate 14.

[0077] The inlet of the second water pump 23 is connected with the outlet of the motor water jacket 24, and the outlet of the second water pump 23 is connected with the B port of the second three-way valve 4.

[0078] The inlet of the gas-liquid separator 6 is connected with the A port of the third heat exchanger 8, and the outlet of the gas-liquid separator 6 is connected with the inlet of the electric compressor 7.

[0079] The first heat exchanger 2 and the second heat exchanger 3 are placed in the front cabin head of the electric vehicle, the fifth heat exchanger 20, the sixth heat exchanger 22 and the blower 19 are placed in the air conditioning box 21, and the air conditioning box 21 is placed in the instrument table of the passenger cabin.

[0080] Specifically, in the refrigerant circuit, the inlet of the electric compressor 7 is connected with the outlet of the gas-liquid separator 6, the outlet is connected with the B port of the four-way reversing valve 9; the A port of the four-way reversing valve 9 is connected with the C port of the third three-way valve 5, the C port of the four-way reversing valve 9 is connected with the A port of the seventh three-way valve 17, the D port of the four-way reversing valve 9 is connected with the B port of the third heat exchanger 8; the A port of the third three-way valve 5 is connected with the B port of the second heat exchanger 3, the B port of the third three-way valve 5 is connected with the A port of the fourth three-way valve 10; the A port of the first three-way valve 1 is connected with the A port of the sixth three-way valve 16, the B port of the first three-way valve 1 is connected with the A port of the second heat exchanger 3, the C port of the first three-way valve 1 is connected with the C port of the third heat exchanger 8; the B port of the fourth three-way valve 10 is connected with the B port of the fifth three-way valve 11, the C port of the fourth three-way valve 10 is connected with the A port of the fourth heat exchanger 13 through the first electronic expansion valve 12; the A port of the fifth three-way valve 11 is connected with the D port of the third heat exchanger 8, the C port of the fifth three-way valve 11 is connected with the B port of the fifth heat exchanger 20 through the second electronic expansion valve 18; the B port of the sixth three-way valve 16 is connected with the C port of the seventh three-way valve 17, the C port of the sixth three-way valve 16 is connected with the B port of the fourth heat exchanger 13; the A port of the sixth heat exchanger 22 is connected with the B port of the seventh three-way valve 17, the B port of the sixth heat exchanger 22 is connected with the A port of the fifth heat exchanger 20; the inlet of the gas-liquid separator 6 is connected with the A port of the third heat exchanger 8.

[0081] In the battery pack cooling liquid circuit, the inlet of the battery pack liquid cooling plate 14 is connected with the outlet of the first water pump 15, the outlet is connected with the C port of the fourth heat exchanger 13; the inlet of the first water pump 15 is connected with the D port of the fourth heat exchanger 13.

[0082] In the motor cooling liquid circuit, the inlet of the motor water jacket 24 is connected with the B port of the eighth three-way valve 25, the outlet is connected with the inlet of the second water pump 23; the outlet of the second water pump 23 is connected with the B port of the second three-way valve 4; the A port of the second three-way valve 4 is connected with the B port of the first heat exchanger 2, the C port of the second three-way valve 4 is connected with the C port of the sixth heat exchanger 22; the D port of the sixth heat exchanger 22 is connected with the C port of the eighth three-way valve 25; the A port of the first heat exchanger 2 is connected with the A port of the eighth three-way valve 25.

[0083] The cooling process includes a first mode, a second mode, a third mode and a fourth mode;

[0084] As Figure 2As shown, regardless of whether the electric vehicle is parked, charging, or driving, if the temperature of the power battery exceeds its optimal temperature range, it automatically enters the first mode. The electronic control unit commands the electric compressor 7 to start. At this time, the four-way reversing valve 9 switches to the AB-CD connection position, the first three-way valve 1 switches to the BC-only connection position, the third three-way valve 5 switches to the AC-only connection position, the fourth three-way valve 10 switches to the BC-only connection position, the fifth three-way valve 11 switches to the AB-only connection position, the sixth three-way valve 16 switches to the BC-only connection position, and the seventh three-way valve 17 switches to the AC-only connection position. The coolant in the battery pack coolant circuit absorbs heat in the battery pack liquid cooling plate 14 under the drive of the first water pump 15 and then flows into the fourth heat exchanger 13, transferring the heat to the refrigerant in the refrigerant circuit. The high-temperature, high-pressure refrigerant discharged by the electric compressor 7 passes through the four-way reversing valve 9 and the third three-way valve 5 before entering the second heat exchanger 3, dissipating heat to the outside of the electric vehicle. It then passes through the first three-way valve 1, the third heat exchanger 8, the fifth three-way valve 11, and the fourth three-way valve 10 before entering the first electronic expansion valve 12 for depressurization and cooling. Subsequently, it enters the fourth heat exchanger 13 to absorb heat from the battery pack coolant. Afterward, it sequentially passes through the sixth three-way valve 16, the seventh three-way valve 17, the four-way reversing valve 9, the third heat exchanger 8, and the gas-liquid separator 6 before returning to the electric compressor 7 for further compression, repeating this process. In the first mode, the heat from the power battery is transferred to the fourth heat exchanger 13 through the circulation of coolant in the battery pack coolant circuit, and then transported to the outside of the electric vehicle through the circulation of refrigerant in the refrigerant circuit, achieving rapid cooling of the power battery.

[0085] like Figure 3 As shown, if the occupants activate the passenger compartment cooling function, the system automatically enters the second mode. The electronic control unit commands the electric compressor 7 and blower 19 to start. At this time, the four-way reversing valve 9 switches to the AB-CD connection position, the first three-way valve 1 switches to the BC-only connection position, the third three-way valve 5 switches to the AC-only connection position, the fifth three-way valve 11 switches to the AC-only connection position, and the seventh three-way valve 17 switches to the AB-only connection position. The high-temperature, high-pressure refrigerant discharged by the electric compressor 7 passes through the four-way reversing valve 9 and the third three-way valve 5 and enters the second heat exchanger 3 to complete supercritical heat release. Subsequently, the refrigerant passes through the first three-way valve 1, the third heat exchanger 8, and the fifth three-way valve 11 and enters the second electronic expansion valve 18 to release pressure and cool down. Then, it enters the fifth heat exchanger 20 and the sixth heat exchanger 22 to absorb heat from the passenger compartment. Finally, it passes through the seventh three-way valve 17, the four-way reversing valve 9, the third heat exchanger 8, and the gas-liquid separator 6 before returning to the electric compressor 7 for further compression, and this process is repeated. In the second mode, the heat from the passenger compartment is transferred to the outside of the electric vehicle through refrigerant circulation, thus cooling the passenger compartment.

[0086] like Figure 4As shown, if the temperature of the power battery is higher than its suitable temperature range and the occupant turns on the cooling function of the passenger compartment, the third mode is automatically entered, and the control unit commands the compressor, the blower 19 and the first water pump 15 to start. At this time, the four-way reversing valve 9 is switched to the AB connection and CD connection position, the first three-way valve 1 is switched to the BC separate connection position, the third three-way valve 5 is switched to the AC separate connection position, the fourth three-way valve 10 is switched to the BC separate connection position, the fifth three-way valve 11 is switched to the AB connection and AC connection position, the sixth three-way valve 16 is switched to the BC separate connection position, and the seventh three-way valve 17 is switched to the AB connection and AC separate connection position. The cooling liquid in the battery pack cooling liquid circuit flows into the fourth heat exchanger 13 after absorbing heat in the battery pack liquid cooling plate 14 under the driving of the first water pump 15. The high-temperature and high-pressure refrigerant discharged by the electric compressor 7 enters the second heat exchanger 3 after passing through the four-way reversing valve 9 and the third three-way valve 5, and dissipates heat to the outside of the electric vehicle. Then, the refrigerant is divided by the first three-way valve 1, the third heat exchanger 8 and the fifth three-way valve 11. Part of the refrigerant enters the fourth heat exchanger 13 after passing through the fourth three-way valve 10 and the first electronic expansion valve 12 to absorb the heat of the power battery in the battery pack. Another part of the refrigerant enters the second electronic expansion valve 18, then enters the fifth heat exchanger 20 and the sixth heat exchanger 22 to absorb the heat of the passenger compartment. Subsequently, the two parts of the refrigerant are merged by the seventh three-way valve 17, and then return to the electric compressor 7 by the four-way reversing valve 9, the third heat exchanger 8 and the gas-liquid separator 6 to continue compression. Through the circulation of the refrigerant, the heat of the passenger compartment and the battery pack is transferred to the outside of the vehicle, and the cooling of the passenger compartment and the battery pack is simultaneously achieved.

[0087] As Figure 5As shown, if the temperature of the power battery and the temperature of the motor both exceed their respective suitable temperature ranges, and the occupant turns on the passenger cabin refrigeration function, the fourth mode is automatically entered, and the control unit commands the compressor, the air blower 19, the first water pump 15, and the second water pump 23 to start. At this time, the four-way reversing valve 9 is switched to the AB connection and CD connection position, the first three-way valve 1 is switched to the BC separate connection position, the second three-way valve 4 is switched to the AB separate connection position, the third three-way valve 5 is switched to the AC separate connection position, the fourth three-way valve 10 is switched to the BC separate connection position, the fifth three-way valve 11 is switched to the AB connection and AC connection position, the sixth three-way valve 16 is switched to the BC separate connection position, the seventh three-way valve 17 is switched to the AB connection and AC separate connection position, and the eighth three-way valve 25 is switched to the AB separate connection position. The cooling liquid in the battery pack cooling liquid circuit is driven by the first water pump 15 to absorb heat in the battery pack liquid cooling plate 14 and then flows into the fourth heat exchanger 13. The high-temperature and high-pressure refrigerant discharged by the electric compressor 7 enters the second heat exchanger 3 after passing through the four-way reversing valve 9 and the third three-way valve 5, and dissipates heat to the outside of the electric vehicle. Then, after passing through the first three-way valve 1, the third heat exchanger 8, and the fifth three-way valve 11, the refrigerant is divided into two parts. One part of the refrigerant enters the fourth heat exchanger 13 after passing through the fourth three-way valve 10 and the first electronic expansion valve 12 to absorb the heat of the power battery in the battery pack. The other part of the refrigerant enters the fifth heat exchanger 20 and the sixth heat exchanger 22 after passing through the second electronic expansion valve 18 to absorb the heat of the passenger cabin. Then, the two parts of the refrigerant are combined after passing through the seventh three-way valve 17, and then return to the compressor after passing through the four-way reversing valve 9, the third heat exchanger 8, and the gas-liquid separator 6 to continue compression. At the same time, the motor cooling liquid absorbs the heat of the motor under the driving of the second water pump 23, and then dissipates to the outside of the vehicle through the first heat exchanger 2. Through the circulation of the refrigerant and the cooling liquid, the heat of the passenger cabin, the power battery, and the motor is transferred to the outside of the vehicle, and the cooling of them is simultaneously realized.

[0088] As Figure 6As shown, if the temperature of the power battery is lower than its suitable temperature range, it will automatically enter the fifth mode. The electronic control unit commands the electric compressor 7 and the first water pump 15 to start. At this time, the four-way reversing valve 9 switches to the AD connected and BC connected position, the first three-way valve 1 switches to the BC connected position, the third three-way valve 5 switches to the AC connected position, the fourth three-way valve 10 switches to the BC connected position, the fifth three-way valve 11 switches to the AB connected position, the sixth three-way valve 16 switches to the BC connected position, and the seventh three-way valve 17 switches to the AC connected position. The high-temperature, high-pressure refrigerant discharged by the electric compressor 7 passes through the four-way reversing valve 9, the seventh three-way valve 17, and the sixth three-way valve 16 before entering the fourth heat exchanger 13 to complete supercritical heat release, transferring heat to the battery pack coolant. Subsequently, the refrigerant passes sequentially through the first electronic expansion valve 12, the fourth three-way valve 10, the fifth three-way valve 11, the third heat exchanger 8, and the first three-way valve 1 before entering the second heat exchanger 3 to absorb heat from outside the electric vehicle. Then, it passes sequentially through the third three-way valve 5, the four-way reversing valve 9, the third heat exchanger 8, and the gas-liquid separator 6 before returning to the electric compressor 7 for further compression, repeating this process. The coolant in the battery pack coolant circuit, driven by the first water pump 15, absorbs heat from the refrigerant in the fourth heat exchanger 13, and then transfers the heat to the battery pack via the battery pack liquid cooling plate 14. In the fifth mode, the heat outside the electric vehicle is transferred to the fourth heat exchanger 13 through the circulation of refrigerant. Then, through the circulation of battery pack coolant, the heat is transferred from the fourth heat exchanger 13 to the power battery in the battery pack, thus achieving the heating of the power battery.

[0089] like Figure 7 As shown, if the passenger compartment heating function is activated, the system automatically enters the sixth mode. The electronic control unit commands the electric compressor 7 and blower 19 to start. At this time, the four-way reversing valve 9 switches to the AD and BC connected position, the first three-way valve 1 switches to the BC connected position, the third three-way valve 5 switches to the AC connected position, the fifth three-way valve 11 switches to the AC connected position, and the seventh three-way valve 17 switches to the AB connected position. The high-temperature and high-pressure refrigerant discharged by the compressor passes through the four-way reversing valve 9 and the seventh three-way valve 17 and enters the fifth heat exchanger 20 and the sixth heat exchanger 22 to complete supercritical heat release. Subsequently, the refrigerant passes through the second electronic expansion valve 18, the fifth three-way valve 11, the third heat exchanger 8, and the first three-way valve 1 and enters the second heat exchanger 3 to absorb heat from outside the vehicle. Then, it passes through the third three-way valve 5, the four-way reversing valve 9, the third heat exchanger 8, and the gas-liquid separator 6 in sequence before returning to the compressor to continue compression, and so on. In this mode, the heat outside the electric vehicle is transferred to the passenger compartment through the circulation of refrigerant in the refrigerant circuit, thereby heating the passenger compartment.

[0090] like Figure 8As shown, if the temperature of the power battery is lower than its suitable temperature range and the heating function of the passenger cabin is turned on, the seventh mode is automatically entered. The electric control unit commands the electric compressor 7, the air blower 19 and the first water pump 15 to start, at this time the four-way reversing valve 9 is switched to the AD connection and BC connection position, the first three-way valve 1 is switched to the BC separate connection position, the third three-way valve 5 is switched to the AC separate connection position, the fourth three-way valve 10 is switched to the BC separate connection position, the fifth three-way valve 11 is switched to the AB connection and AC connection position, the sixth three-way valve 16 is switched to the BC separate connection position, and the seventh three-way valve 17 is switched to the AB connection and AC connection position. The high-temperature and high-pressure refrigerant discharged by the electric compressor 7 enters the seventh three-way valve 17 after passing through the four-way reversing valve 9, and a part of the refrigerant enters the fourth heat exchanger 13 to release heat, and then enters the fifth three-way valve 11 in turn through the first electronic expansion valve 12 and the fourth three-way valve 10. Another part of the refrigerant enters the sixth heat exchanger 22 and the fifth heat exchanger 20 to release heat to the passenger cabin, and then enters the fifth three-way valve 11 through the second electronic expansion valve 18, and then enters the second heat exchanger 3 through the third heat exchanger 8 and the first three-way valve 1 to absorb heat outside the electric vehicle, and then enters the electric compressor 7 in turn through the third three-way valve 5, the four-way reversing valve 9, the third heat exchanger 8 and the gas-liquid separator 6 to continue compression, and so on. In the seventh mode, through the circulation of the refrigerant in the refrigerant circuit, the heat outside the electric vehicle is transferred to the fourth heat exchanger 13 and the passenger cabin, respectively, and then through the circulation of the battery pack cooling liquid, the heat is transferred from the fourth heat exchanger 13 to the power battery of the battery pack, achieving the common heating of the power battery and the passenger cabin.

[0091] As Figure 9As shown, if the temperature of the power battery is lower than its suitable temperature range and the temperature of the motor is higher than its minimum temperature (for example, when the electric vehicle is cold started, the waste heat generated by the motor is used to heat the power battery), the eighth mode is automatically entered. The electronic control unit commands the electric compressor 7, the first water pump 15, and the second water pump 23 to start, at this time, all the ports in the first electronic expansion valve 12 are fully opened, the four-way reversing valve 9 is switched to the AB connection and CD connection position, the first three-way valve 1 is switched to the AC separate connection position, the second three-way valve 4 is switched to the BC separate connection position, the third three-way valve 5 is switched to the BC separate connection position, the fourth three-way valve 10 is switched to the AC separate connection position, the fifth three-way valve 11 is switched to the AC separate connection position, the sixth three-way valve 16 is switched to the AC separate connection position, the seventh three-way valve 17 is switched to the AB separate connection position, and the eighth three-way valve 25 is switched to the BC separate connection position. The cooling liquid in the motor cooling liquid circuit is driven by the second water pump 23 to absorb the heat of the motor, and then enters the sixth heat exchanger 22 to release heat after passing through the second three-way valve 4. The high-temperature and high-pressure refrigerant discharged by the compressor enters the fourth heat exchanger 13 to release heat after passing through the four-way reversing valve 9, the third three-way valve 5, the fourth three-way valve 10, and the first electronic expansion valve 12, and then enters the second electronic expansion valve 18 in sequence after passing through the sixth three-way valve 16, the first three-way valve 1, the third heat exchanger 8, and the fifth three-way valve 11 to release pressure and reduce temperature, and then enters the sixth heat exchanger 22 to absorb heat after passing through the fifth heat exchanger 20 (at this time, the air blower 19 is closed and does not exchange heat with air), and then enters the electric compressor 7 to continue compression after passing through the seventh three-way valve 17, the four-way reversing valve 9, the third heat exchanger 8, and the gas-liquid separator 6. The cooling liquid in the battery pack cooling liquid circuit is driven by the first water pump 15 to absorb the heat of the refrigerant in the fourth heat exchanger 13, and then sends the heat to the power battery of the battery pack through the battery pack liquid cooling plate 14. In the eighth mode, the heat of the motor is transferred to the sixth heat exchanger 22 through the circulation of the cooling liquid in the motor cooling liquid circuit, and then transferred to the fourth heat exchanger 13 through the circulation of the refrigerant in the refrigerant circuit, and then transferred to the power battery by the battery pack liquid cooling plate 14, realizing heating the power battery by the heat of the motor.

[0092] As Figure 10As shown, if the temperature of the power battery is lower than its suitable temperature range, the passenger compartment starts heating function, and the temperature of the motor is higher than its suitable temperature range, the ninth mode is automatically entered. The electric control unit commands the electric compressor 7, the air blower 19, the first water pump 15 and the second water pump 23 to start, at this time the four-way reversing valve 9 is switched to the AD connection and BC connection position, the first three-way valve 1 is switched to the BC separate connection position, the second three-way valve 4 is switched to the BC separate connection position, the third three-way valve 5 is switched to the AC separate connection position, the fourth three-way valve 10 is switched to the BC separate connection position, the fifth three-way valve 11 is switched to the AB connection and AC connection position, the sixth three-way valve 16 is switched to the BC separate connection position, the seventh three-way valve 17 is switched to the AB connection and AC connection position, and the eighth three-way valve 25 is switched to the BC separate connection position. The cooling liquid in the motor cooling liquid circuit absorbs the heat of the motor, and then enters the sixth heat exchanger 22 under the driving of the second water pump 23 to transfer the heat to the refrigerant in the refrigerant circuit. The high-temperature and high-pressure refrigerant discharged by the electric compressor 7 is divided by the four-way reversing valve 9 and the seventh three-way valve 17, part of the refrigerant enters the fourth heat exchanger 13 by the sixth three-way valve 16 to release heat, and then enters the fifth three-way valve 11 in turn through the first electronic expansion valve 12 and the fourth three-way valve 10; the other part of the refrigerant enters the sixth heat exchanger 22 to absorb the heat of the motor cooling liquid and releases heat to the passenger compartment through the air blower 19, and then enters the fifth heat exchanger 20 to continue releasing heat to the passenger compartment, and then enters the fifth three-way valve 11 after being depressurized by the second electronic expansion valve 18, and then merges with the refrigerant flowing through the fourth heat exchanger 13, and then enters the second heat exchanger 3 through the third heat exchanger 8 and the first three-way valve 1 to absorb the heat outside the electric vehicle, and then enters the third heat exchanger 8 and the gas-liquid separator 6 in turn through the third three-way valve 5, the four-way reversing valve 9 and the third heat exchanger 8, and then returns to the electric compressor 7 to continue compression, and so on. The cooling liquid in the battery pack cooling liquid circuit absorbs the heat of the refrigerant in the fourth heat exchanger 13 under the driving of the first water pump 15, and then sends the heat to the power battery of the battery pack through the battery pack liquid cooling plate 14. In the ninth mode, the heat outside the electric vehicle is moved to the fourth heat exchanger 13 and the fifth heat exchanger 20 through the circulation of the refrigerant in the refrigerant circuit, the heat of the motor is transferred to the air in the passenger compartment and the refrigerant through the sixth heat exchanger 22, the temperature of the refrigerant entering the fifth heat exchanger 20 is improved, and the air supply temperature of the passenger compartment is also improved.

[0093] As Figure 11As shown, if the temperature of the power battery is higher than the appropriate temperature range and the heating function of the passenger cabin is turned on, the tenth mode is automatically entered. The electric control unit commands the electric compressor 7, the blower 19 and the first water pump 15 to start, and each port in the first electronic expansion valve 12 is opened. At this time, the four-way reversing valve 9 is switched to the AD connection and BC connection position, the first three-way valve 1 is switched to the AC connection and BC connection position, the third three-way valve 5 is switched to the AC connection and BC connection position, the fourth three-way valve 10 is switched to the AC separate connection position, the fifth three-way valve 11 is switched to the AC separate connection position, the sixth three-way valve 16 is switched to the AC separate connection position, and the seventh three-way valve 17 is switched to the AB separate connection position. The battery pack cooling liquid absorbs the heat of the power battery in the battery pack, enters the fourth heat exchanger 13 under the drive of the first water pump 15, and transfers the heat to the refrigerant in the refrigerant circuit. The high-temperature and high-pressure refrigerant discharged by the electric compressor 7 enters the sixth heat exchanger 22 and the fifth heat exchanger 20 after passing through the four-way reversing valve 9 and the seventh three-way valve 17 to heat the passenger cabin. Then, the temperature is lowered by the second electronic expansion valve 18, and then enters the first three-way valve 1 after passing through the fifth three-way valve 11 and the third heat exchanger 8. Part of the refrigerant flows into the second heat exchanger 3 to absorb the heat outside the electric vehicle, and the other part of the refrigerant enters the fourth heat exchanger 13 after passing through the sixth three-way valve 16 to absorb the heat of the cooling liquid in the battery pack cooling liquid circuit. Then, after passing through the first electronic expansion valve 12 and the fourth three-way valve 10, the refrigerant is combined with the refrigerant flowing through the second heat exchanger 3 in the third three-way valve 5. Then, after passing through the four-way reversing valve 9, the third heat exchanger 8 and the gas-liquid separator 6, the refrigerant returns to the electric compressor 7 for continuous compression. In the ninth mode, the heat of the power battery in the battery pack is transferred to the refrigerant, and then the heat of the electric vehicle outside and the heat of the power battery in the battery pack are moved to the passenger cabin, realizing the use of the waste heat of the power battery to heat the passenger cabin.

[0094] As Figure 12As shown, if the temperature of the power battery is higher than its suitable temperature range, the passenger compartment starts heating function, and the temperature of the motor is higher than its suitable temperature range, the eleventh mode is automatically entered. The electric control unit commands the electric compressor 7, the blower 19, the first water pump 15, and the second water pump 23 to start. At this time, the first electronic expansion valve 12 is in the full open position, the four-way reversing valve 9 is switched to the AD connection and BC connection position, the first three-way valve 1 is switched to the AC connection and BC connection position, the second three-way valve 4 is switched to the BC separate connection position, the third three-way valve 5 is switched to the AC connection and BC connection position, the fourth three-way valve 10 is switched to the AC separate connection position, the fifth three-way valve 11 is switched to the AC separate connection position, the sixth three-way valve 16 is switched to the AC separate connection position, the seventh three-way valve 17 is switched to the AB separate connection position, and the eighth three-way valve 25 is switched to the BC separate connection position. The cooling liquid in the battery pack cooling liquid circuit absorbs the heat of the power battery in the battery pack, enters the fourth heat exchanger 13 under the driving of the first water pump 15, and transfers the heat to the refrigerant in the refrigerant circuit. The cooling liquid in the motor cooling liquid circuit absorbs the heat of the motor, enters the fifth heat exchanger 20 under the driving of the second water pump 23, and transfers the heat to the refrigerant and the passenger compartment air. The high-temperature and high-pressure refrigerant discharged by the electric compressor 7 enters the sixth heat exchanger 22 after passing through the four-way reversing valve 9 and the seventh three-way valve 17, absorbs the heat of the motor cooling liquid, then enters the fifth heat exchanger 20 to release heat, then is depressurized and cooled by the second electronic expansion valve 18, then enters the first three-way valve 1 after passing through the fifth three-way valve 11 and the third heat exchanger 8, and is divided into two parts, one part flows into the second heat exchanger 3 to absorb the heat outside the electric vehicle, and the other part enters the fourth heat exchanger 13 after passing through the sixth three-way valve 16 to absorb the heat of the battery pack liquid cooling plate 14, then passes through the first electronic expansion valve 12 and the fourth three-way valve 10, and is combined with the refrigerant flowing through the second heat exchanger 3 at the third three-way valve 5, then returns to the electric compressor 7 to continue compression after passing through the four-way reversing valve 9, the third heat exchanger 8, and the gas-liquid separator 6. In this way, the heat of the power battery in the battery pack is transferred to the refrigerant, and the heat outside the electric vehicle and the heat of the power battery are moved into the passenger compartment through the refrigerant circulation; at the same time, the heat of the motor is transferred to the refrigerant and the passenger compartment air, further improving the heating efficiency of the passenger compartment.

[0095] As Figure 13As shown, if the passenger compartment opens the heating function, and the outlet temperature of the motor water jacket 24 > 80℃, then automatically enter the twelfth mode. The control unit commands the blower 19 and the second water pump 23 start. The control unit commands the second water pump 23 start, the second three-way valve 4 switches to the BC separate communication position, the eighth three-way valve 25 switches to the BC separate communication position. The cooling liquid in the motor cooling liquid circuit absorbs the heat of the motor under the driving of the second water pump 23, and then flows into the sixth heat exchanger 22. Due to the action of the blower 19, the air absorbs the heat of the cooling liquid in the motor cooling liquid circuit in the sixth heat exchanger 22, and heats the passenger compartment. In the twelfth mode, the temperature of the motor is high, so it is not necessary to rely on the heat pump cycle to realize the heating of the passenger compartment, and the heating efficiency is high.

[0096] As shown, if the passenger compartment opens the heating function, and the outlet temperature of the motor water jacket 24 > 80℃, then automatically enter the twelfth mode. The control unit commands the blower 19 and the second water pump 23 start. The control unit commands the second water pump 23 start, the second three-way valve 4 switches to the BC separate communication position, the eighth three-way valve 25 switches to the BC separate communication position. The cooling liquid in the motor cooling liquid circuit absorbs the heat of the motor under the driving of the second water pump 23, and then flows into the sixth heat exchanger 22. Due to the action of the blower 19, the air absorbs the heat of the cooling liquid in the motor cooling liquid circuit in the sixth heat exchanger 22, and heats the passenger compartment. In the twelfth mode, the temperature of the motor is high, so it is not necessary to rely on the heat pump cycle to realize the heating of the passenger compartment, and the heating efficiency is high. Figure 14 As shown, if the passenger compartment opens the heating function, and the outlet temperature of the motor water jacket 24 > 80℃, then automatically enter the twelfth mode. The control unit commands the blower 19 and the second water pump 23 start. The control unit commands the second water pump 23 start, the second three-way valve 4 switches to the BC separate communication position, the eighth three-way valve 25 switches to the BC separate communication position. The cooling liquid in the motor cooling liquid circuit absorbs the heat of the motor under the driving of the second water pump 23, and then flows into the sixth heat exchanger 22. Due to the action of the blower 19, the air absorbs the heat of the cooling liquid in the motor cooling liquid circuit in the sixth heat exchanger 22, and heats the passenger compartment. In the twelfth mode, the temperature of the motor is high, so it is not necessary to rely on the heat pump cycle to realize the heating of the passenger compartment, and the heating efficiency is high.

[0097] Of course, the above description is not a limitation on the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the spirit and scope of the present application should also be included in the protection scope of the present application.

Claims

1. A multi-domain coupled thermal management system for electric vehicles based on transcritical CO2 cycle, characterized in that: The application relates to a refrigerant circuit, a battery pack cooling liquid circuit, a motor cooling liquid circuit and an electronic control unit, wherein the electronic control unit is connected with each circuit, the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit are connected through the communication position change of a plurality of valves, and a cooling process, a heating process and a waste heat utilization process are formed. The refrigerant circuit comprises an electric compressor (7), a four-way reversing valve (9), a gas-liquid separator (6), a first electronic expansion valve (12), a second electronic expansion valve (18), a second heat exchanger (3), a third heat exchanger (8), an AB passage of a fourth heat exchanger (13), an AB passage of a fifth heat exchanger (20) and a sixth heat exchanger (22), a first three-way valve (1), a third three-way valve (5), a fourth three-way valve (10), a fifth three-way valve (11), a sixth three-way valve (16) and a seventh three-way valve (17), the outlet of the electric compressor (7) is connected with the B end of the four-way reversing valve (9), and each component is connected; The battery pack cooling liquid circuit comprises a battery pack liquid cooling plate (14), a first water pump (15) and a CD passage of the fourth heat exchanger (13), and each component is connected; The motor cooling liquid circuit comprises a motor water jacket (24), a second water pump (23), a second three-way valve (4), an eighth three-way valve (25), a CD passage of a first heat exchanger (2) and a sixth heat exchanger (22), and each component is connected; The refrigerant circuit adopts carbon dioxide refrigerant, the battery pack cooling liquid circuit and the motor cooling liquid circuit both adopt water-glycol cooling liquid. In the refrigerant circuit, the inlet of the electric compressor (7) is connected with the outlet of the gas-liquid separator (6), the outlet of the electric compressor (7) is connected with the B port of the four-way reversing valve (9); the A port of the four-way reversing valve (9) is connected with the C port of the third three-way valve (5), the C port of the four-way reversing valve (9) is connected with the A port of the seventh three-way valve (17), the D port of the four-way reversing valve (9) is connected with the B port of the third heat exchanger (8); the A port of the third three-way valve (5) is connected with the B port of the second heat exchanger (3), the B port of the third three-way valve (5) is connected with the A port of the fourth three-way valve (10); the A port of the first three-way valve (1) is connected with the A port of the sixth three-way valve (16), the B port of the first three-way valve (1) is connected with the A port of the second heat exchanger (3), the C port of the first three-way valve (1) is connected with the C port of the third heat exchanger (8); the B port of the fourth three-way valve (10) is connected with the B port of the fifth three-way valve (11), the C port of the fourth three-way valve (10) is connected with the A port of the fourth heat exchanger (13) through the first electronic expansion valve (12); the A port of the fifth three-way valve (11) is connected with the D port of the third heat exchanger (8), the C port of the fifth three-way valve (11) is connected with the B port of the fifth heat exchanger (20) through the second electronic expansion valve (18); the B port of the sixth three-way valve (16) is connected with the C port of the seventh three-way valve (17), the C port of the sixth three-way valve (16) is connected with the B port of the fourth heat exchanger (13); the A port of the sixth heat exchanger (22) is connected with the B port of the seventh three-way valve (17), the B port of the sixth heat exchanger (22) is connected with the A port of the fifth heat exchanger (20); the inlet of the gas-liquid separator (6) is connected with the A port of the third heat exchanger (8); In the battery pack cooling liquid circuit, the inlet of the battery pack liquid cooling plate (14) is connected with the outlet of the first water pump (15), the outlet of the battery pack liquid cooling plate (14) is connected with the C port of the fourth heat exchanger (13); the inlet of the first water pump (15) is connected with the D port of the fourth heat exchanger (13); In the motor cooling liquid circuit, the inlet of the motor water jacket (24) is connected with the B port of the eighth three-way valve (25), the outlet is connected with the inlet of the second water pump (23); the outlet of the second water pump (23) is connected with the B port of the second three-way valve (4); the A port of the second three-way valve (4) is connected with the B port of the first heat exchanger (2), the C port of the second three-way valve (4) is connected with the C port of the sixth heat exchanger (22); the D port of the sixth heat exchanger (22) is connected with the C port of the eighth three-way valve (25); the A port of the first heat exchanger (2) is connected with the A port of the eighth three-way valve (25).

2. The multi-domain coupled thermal management system for electric vehicles based on transcritical CO2 cycle of claim 1, wherein: The electric control unit is connected with the electric compressor (7), the first water pump (15), the second water pump (23), the air blower (19), the first three-way valve (1), the second three-way valve (4), the third three-way valve (5), the fourth three-way valve (10), the fifth three-way valve (11), the sixth three-way valve (16), the seventh three-way valve (17), the eighth three-way valve (25), the four-way reversing valve (9), the first electronic expansion valve (12) and the second electronic expansion valve (18) respectively, and is used for controlling the on-off of the electric compressor (7), the first water pump (15), the second water pump (23) and the air blower (19) and the communication position of the ports in the valves.

3. The multi-domain coupled thermal management system for electric vehicles based on transcritical CO2 cycle of claim 2, wherein: The first heat exchanger (2) is a finned tube heat exchanger and is used for heat exchange between the motor cooling liquid and air; the second heat exchanger (3) and the fifth heat exchanger (20) are both finned tube heat exchangers and are used for heat exchange between the refrigerant and air; the third heat exchanger (8) is a double-pipe heat exchanger and has two passages, AB and CD, and the refrigerants in the two passages can exchange heat; the fourth heat exchanger (13) is a plate heat exchanger, AB is a refrigerant passage and CD is a battery pack cooling liquid passage, and the fourth heat exchanger (13) is used for heat exchange between the refrigerant and the battery pack cooling liquid; the sixth heat exchanger (22) is a three-medium heat exchanger and has three passages, AB, CD and air, AB is a refrigerant passage and CD is a motor cooling liquid passage, the sixth heat exchanger (22) has fins outside and is used for heat exchange between the refrigerant and the motor cooling liquid or between the motor cooling liquid and air.

4. The multi-domain coupled thermal management system for electric vehicles based on transcritical CO2 cycle of claim 3, wherein: The cooling process includes a first mode, a second mode, a third mode and a fourth mode; If the temperature of the power battery exceeds the suitable temperature range, the first mode is automatically entered, the first mode cooperates the battery pack cooling liquid circuit with the refrigerant circuit to transfer the heat of the power battery to the outside, so that the power battery is cooled; the electric control unit controls the electric compressor (7) to start, the four-way reversing valve (9) is switched to the AB communication and CD communication position, the first three-way valve (1) is switched to the BC separate communication position, the third three-way valve (5) is switched to the AC separate communication position, the fourth three-way valve (10) is switched to the BC separate communication position, the fifth three-way valve (11) is switched to the AB separate communication position, the sixth three-way valve (16) is switched to the BC separate communication position, and the seventh three-way valve (17) is switched to the AC separate communication position; If the passenger compartment refrigeration function is started, the second mode is automatically entered, the first mode circulates the refrigerant in the refrigerant circuit to transfer the heat of the passenger compartment to the outside, so that the passenger compartment is cooled; the electric control unit controls the electric compressor (7) and the air blower (19) to start, the four-way reversing valve (9) is switched to the AB communication and CD communication position, the first three-way valve (1) is switched to the BC separate communication position, the third three-way valve (5) is switched to the AC separate communication position, the fifth three-way valve (11) is switched to the AC separate communication position, and the seventh three-way valve (17) is switched to the AB separate communication position; If the temperature of the power battery exceeds the appropriate temperature range and the user turns on the passenger cabin refrigeration function, the third mode is automatically entered, the third mode cooperates the battery pack cooling liquid circuit with the refrigerant circuit to transfer the heat of the passenger cabin and the power battery to the outside, and the synchronous cooling of the passenger cabin and the power battery is realized; the electric control unit controls the electric compressor (7), the air blower (19) and the first water pump (15) to be turned on, the four-way reversing valve (9) is switched to the AB connection and CD connection position, the first three-way valve (1) is switched to the BC separate connection position, the third three-way valve (5) is switched to the AC separate connection position, the fourth three-way valve (10) is switched to the BC separate connection position, the fifth three-way valve (11) is switched to the AB connection and AC connection position, the sixth three-way valve (16) is switched to the BC separate connection position, and the seventh three-way valve (17) is switched to the AB connection and AC separate connection position; If the temperature of the power battery and the motor both exceed the appropriate temperature range, and the passenger cabin refrigeration function is turned on, the fourth mode is automatically entered, the fourth mode cooperates the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit to transfer the heat of the passenger cabin, the power battery and the motor to the outside, and the cooling is realized; the electric control unit controls the electric compressor (7), the air blower (19), the first water pump (15) and the second water pump (23) to be turned on, the four-way reversing valve (9) is switched to the AB connection and CD connection position, the first three-way valve (1) is switched to the BC separate connection position, the second three-way valve (4) is switched to the AB separate connection position, the third three-way valve (5) is switched to the AC separate connection position, the fourth three-way valve (10) is switched to the BC separate connection position, the fifth three-way valve (11) is switched to the AB connection and AC connection position, the sixth three-way valve (16) is switched to the BC separate connection position, the seventh three-way valve (17) is switched to the AB connection and AC separate connection position, and the eighth three-way valve (25) is switched to the AB separate connection position.

5. The multi-domain coupled thermal management system for electric vehicles based on transcritical CO2 cycle of claim 3, wherein: The heating process includes the fifth mode, the sixth mode and the seventh mode; If the temperature of the power battery is lower than the appropriate temperature range, the fifth mode is automatically entered, the fifth mode cooperates the refrigerant circuit and the battery pack cooling liquid circuit to transfer the heat of the outside to the power battery, and the heating of the power battery is realized; the electric control unit controls the electric compressor (7) and the first water pump (15) to be turned on, the four-way reversing valve (9) is switched to the AD connection and BC connection position, the first three-way valve (1) is switched to the BC separate connection position, the third three-way valve (5) is switched to the AC separate connection position, the fourth three-way valve (10) is switched to the BC separate connection position, the fifth three-way valve (11) is switched to the AB separate connection position, the sixth three-way valve (16) is switched to the BC separate connection position, and the seventh three-way valve (17) is switched to the AC separate connection position; If the passenger cabin heating function is turned on, the sixth mode is automatically entered, and the sixth mode transmits external heat to the passenger cabin through the circulation of refrigerant in the refrigerant circuit to realize heating of the passenger cabin; the electric control unit controls the electric compressor (7) and the air blower (19) to be turned on, the four-way reversing valve (9) is switched to the AD communication and BC communication position, the first three-way valve (1) is switched to the BC separate communication position, the third three-way valve (5) is switched to the AC separate communication position, the fifth three-way valve (11) is switched to the AC separate communication position, and the seventh three-way valve (17) is switched to the AB separate communication position; If the temperature of the power battery is lower than the appropriate temperature range and the passenger cabin heating function is turned on, the seventh mode is automatically entered, and the seventh mode transmits external heat to the passenger cabin and the power battery through the cooperation of the refrigerant circuit and the battery pack cooling liquid circuit to realize synchronous heating of the power battery and the passenger cabin; the electric control unit controls the electric compressor (7), the air blower (19), and the first water pump (15) to be turned on, the four-way reversing valve (9) is switched to the AD communication and BC communication position, the first three-way valve (1) is switched to the BC separate communication position, the third three-way valve (5) is switched to the AC separate communication position, the fourth three-way valve (10) is switched to the BC separate communication position, the fifth three-way valve (11) is switched to the AB communication and AC communication position, the sixth three-way valve (16) is switched to the BC separate communication position, and the seventh three-way valve (17) is switched to the AB communication and AC communication position.

6. The multi-domain coupled thermal management system for electric vehicles based on transcritical CO2 cycle of claim 3, wherein: The waste heat utilization process includes the eighth mode, the ninth mode, the tenth mode, and the eleventh mode; If the temperature of the power battery is lower than the appropriate temperature range and the temperature of the motor is higher than the minimum temperature thereof, the eighth mode is automatically entered, and the eighth mode transmits motor heat to the power battery through the cooperation of the battery pack cooling liquid circuit, the motor cooling liquid circuit, and the refrigerant circuit to realize heating of the power battery; the electric control unit commands the electric compressor (7), the first water pump (15), and the second water pump (23) to be started, the first electronic expansion valve (12) is in the full open position, the four-way reversing valve (9) is switched to the AB communication and CD communication position, the first three-way valve (1) is switched to the AC separate communication position, the second three-way valve (4) is switched to the BC separate communication position, the third three-way valve (5) is switched to the BC separate communication position, the fourth three-way valve (10) is switched to the AC separate communication position, the fifth three-way valve (11) is switched to the AC separate communication position, the sixth three-way valve (16) is switched to the AC separate communication position, the seventh three-way valve (17) is switched to the AB separate communication position, and the eighth three-way valve (25) is switched to the BC separate communication position; If the temperature of the power battery is lower than the suitable temperature range, the passenger compartment opens the heating function, and the temperature of the motor is higher than the suitable temperature range, the ninth mode is automatically entered, the ninth mode cooperates the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit to transfer the heat from the outside and the motor to the power battery and the passenger compartment, realizing the synchronous heating of the power battery and the passenger compartment; the electric control unit controls the electric compressor (7), the air blower (19), the first water pump (15) and the second water pump (23) to open, the four-way reversing valve (9) is switched to the AD communication and BC communication position, the first three-way valve (1) is switched to the BC separate communication position, the second three-way valve (4) is switched to the BC separate communication position, the third three-way valve (5) is switched to the AC separate communication position, the fourth three-way valve (10) is switched to the BC separate communication position, the fifth three-way valve (11) is switched to the AB communication and AC communication position, the sixth three-way valve (16) is switched to the BC separate communication position, the seventh three-way valve (17) is switched to the AB communication and AC communication position, and the eighth three-way valve (25) is switched to the BC separate communication position; If the temperature of the power battery exceeds the suitable temperature range and the passenger compartment opens the heating function, the tenth mode is automatically entered, the tenth mode cooperates the refrigerant circuit and the battery pack cooling liquid circuit to transfer the heat from the outside and the battery pack to the passenger compartment, realizing the heating of the passenger compartment; the electric control unit controls the electric compressor (7), the air blower (19) and the first water pump (15) to open, the first electronic expansion valve (12) is in the full open position, the four-way reversing valve (9) is switched to the AD communication and BC communication position, the first three-way valve (1) is switched to the AC communication and BC communication position, the third three-way valve (5) is switched to the AC communication and BC communication position, the fourth three-way valve (10) is switched to the AC separate communication position, the fifth three-way valve (11) is switched to the AC separate communication position, the sixth three-way valve (16) is switched to the AC separate communication position, and the seventh three-way valve (17) is switched to the AB separate communication position; If the temperature of the power battery exceeds the appropriate temperature range, the passenger compartment opens the heating function, and the temperature of the motor exceeds the appropriate temperature range, the eleventh mode is automatically entered, and the eleventh mode cooperates with the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit to transfer the heat of the outside, the power battery and the motor to the passenger compartment, and heat is supplied to the passenger compartment; the electric control unit controls the electric compressor (7), the air blower (19), the first water pump (15) and the second water pump (23) to be opened, the first electronic expansion valve (12) is in the full open position, the four-way reversing valve (9) is switched to the AD communication and BC communication position, the first three-way valve (1) is switched to the AC communication and BC communication position, the second three-way valve (4) is switched to the BC separate communication position, the third three-way valve (5) is switched to the AC communication and BC communication position, the fourth three-way valve (10) is switched to the AC separate communication position, the fifth three-way valve (11) is switched to the AC separate communication position, the sixth three-way valve (16) is switched to the AC separate communication position, the seventh three-way valve (17) is switched to the AB separate communication position, and the eighth three-way valve (25) is switched to the BC separate communication position.

7. The electric vehicle multi-domain coupled thermal management system based on transcritical CO2 cycle of claim 6, wherein: The waste heat utilization process also includes twelfth and thirteenth modes; If the passenger compartment opens the heating function and the temperature of the motor water jacket (24) outlet is greater than 80℃, the twelfth mode is automatically entered, and the twelfth mode circulates the cooling liquid in the motor cooling liquid circuit to transfer the heat of the motor to the passenger compartment to heat the passenger compartment; the electric control unit controls the second water pump (23) to be opened, the second three-way valve (4) is switched to the BC separate communication position, and the eighth three-way valve (25) is switched to the BC separate communication position; If the passenger compartment opens the heating function, the temperature of the motor water jacket (24) outlet is greater than 80℃, and the temperature of the power battery exceeds the appropriate temperature range, the thirteenth mode is automatically entered, and the thirteenth mode cooperates with the refrigerant circuit, the battery pack cooling liquid circuit and the motor cooling liquid circuit to transfer the heat of the motor to the passenger compartment to heat the passenger compartment, reduce the passenger compartment heating energy consumption, and cool the power battery using the outside environment; the electric control unit controls the electric compressor (7), the air blower (19), the first water pump (15) and the second water pump (23) to be opened, the four-way reversing valve (9) is switched to the AB communication and CD communication position, the first three-way valve (1) is switched to the BC separate communication position, the second three-way valve (4) is switched to the BC separate communication position, the third three-way valve (5) is switched to the AC separate communication position, the fourth three-way valve (10) is switched to the BC separate communication position, the fifth three-way valve (11) is switched to the AB separate communication position, the sixth three-way valve (16) is switched to the BC separate communication position, the seventh three-way valve (17) is switched to the AC separate communication position, and the eighth three-way valve (25) is switched to the BC separate communication position.

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