R290-based electric vehicle thermal management system and control method thereof

Abstract

The invention discloses a whole electric vehicle thermal management system based on R290 and a control method of the whole electric vehicle thermal management system. The system comprises a heat pump system, a first heat transfer loop, a second heat transfer loop, a battery loop and an electric drive cooling system. A refrigerant of the heat pump system is R290, and the whole heat pump circulation loop is arranged in a front cabin of the vehicle; the first heat transfer loop can obtain heat from the heat pump system through the first heat exchanger and transfer the heat to the first radiator or the warm air core body; the second heat transfer loop can obtain cold energy from the heat pump system through the second heat exchanger and transfer the cold energy to the second radiator or the cold air core body; the battery loop is connected with the first heat transfer loop and the second heat transfer loop through pipelines, so that the temperature of the battery pack can be adjusted; the electric drive cooling system is connected with the second heat transfer loop through a pipeline, and heat of the electric drive system can be dissipated through the second radiator or provided for the heat pump system through the second heat exchanger.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management, and in particular to an R290-based electric vehicle thermal management system and a control method thereof. Background Art

[0002] With the growth of sales of domestic new energy vehicles at home and abroad, the use areas are gradually spreading to tropical, temperate, cold and extremely cold regions. Many problems caused by various climate environments in the use process are gradually exposed. Among them, the serious attenuation of cruising range in high and low temperature environments and the greatly extended fast charging time are two of the many pain points of current pure electric vehicle users. Mastering the development of vehicle thermal management and improving the problems of cruising range attenuation and extended fast charging time in high and low temperature environments are one of the key points in the development of electric vehicles. At the same time, under the background of the "dual carbon" goal, on September 15, 2021, China officially signed the Montreal Protocol-Kigali Amendment. The refrigerant R134a, which is currently widely used in automotive thermal management systems, is facing a freeze in usage. In the future, the use of third-generation refrigerants including R134a will be reduced to 80% by 2045. The development of a vehicle thermal management system based on the next generation of environmentally friendly refrigerants is imminent.

[0003] R290 refrigerant has excellent physical properties and a low boiling point at the same pressure, which is conducive to improving the heating capacity of heat pumps at extremely low temperatures, thereby improving the problem of electric vehicles' extreme low temperature endurance attenuation. Its operating pressure is similar to that of the existing R134a system, and the system components have been slightly modified. At the same time, R290 has a large unit volume of cooling / heating, which is conducive to the miniaturization of the system, thereby reducing costs. However, R290 is a flammable substance with a safety level of A3, and the thermal management system based on R290 requires additional safety research. Summary of the invention

[0004] The problem to be solved by the present invention is to overcome the defects of the prior art, provide an electric vehicle thermal management system based on R290 and a control method thereof, design a thermal management system based on R290, and improve the safety of R290 refrigerant during use.

[0005] In order to solve the above technical problems, the present invention provides, on one hand, a thermal management system for an electric vehicle based on R290, comprising a heat pump system, a first heat transfer circuit, a second heat transfer circuit, a battery circuit and an electric drive cooling system; the heat pump system comprises a heat pump circulation circuit consisting of a first heat exchanger, a compressor, a second heat exchanger and an expansion valve, and the refrigerant of the heat pump circulation circuit is R290, and the entire heat pump circulation circuit is arranged in the front cabin of the vehicle; the first heat transfer circuit can obtain heat from the heat pump system through the first heat exchanger, and transfer the heat to the first radiator or the warm air core; the second heat transfer circuit can obtain cold energy from the heat pump system through the second heat exchanger, and transfer the cold energy to the second radiator or the cold air core; the battery circuit is connected to the first heat transfer circuit and the second heat transfer circuit through a pipeline, so as to realize the temperature regulation of the battery pack; the electric drive cooling system is connected to the second heat transfer circuit through a pipeline, so as to dissipate the heat of the electric drive system through the second radiator, and also to provide the heat of the electric drive system to the heat pump system through the second heat exchanger.

[0006] In the above R290-based electric vehicle thermal management system, a dual secondary circuit indirect heat pump design is formed through the first heat transfer circuit and the second heat transfer circuit to achieve temperature regulation of the vehicle passenger compartment. The entire heat pump circulation circuit can be integrated and arranged in the front cabin of the vehicle, and the flammable refrigerant R290 does not enter the member cabin, reducing the risk of R290 leaking into the member cabin. Compared with the traditional arrangement of the evaporator in the air inlet channel of the passenger cabin, the safety hazard caused by refrigerant leakage is greatly reduced. In addition, the entire heat pump circulation circuit has a tight structure and high integration, and the R290 filling amount is small, which improves system safety.

[0007] As an improvement of the R290-based electric vehicle thermal management system of the present invention, the heat pump system also includes a liquid storage tank; the outlet of the compressor is connected to the d port of the first heat exchanger; the c port of the first heat exchanger is connected to the liquid storage tank, the liquid storage tank is connected to the a port of the second heat exchanger, and the expansion valve is arranged on the connecting pipeline; the b port of the second heat exchanger is connected to the inlet of the compressor.

[0008] Preferably, the heat pump system further comprises a first pressure and temperature sensor and a second pressure and temperature sensor, wherein the first pressure and temperature sensor is used to detect the refrigerant temperature and pressure at the outlet of the compressor, and the second pressure and temperature sensor is used to detect the refrigerant temperature and pressure at the inlet of the compressor, and the normal operation of the entire heat pump system is ensured through detection and monitoring. The c port and the d port of the first heat exchanger are connected.

[0009] As another improvement of the R290-based electric vehicle thermal management system of the present invention, the first heat transfer circuit includes a first circulation pump, a three-way valve A, the heater core, a blower, a first radiator and a first heat exchanger; the outlet of the first circulation pump is connected to the a port of the three-way valve A; the c port of the three-way valve A is connected to the heater core; the heater core is connected to the a port of the first heat exchanger; the b port of the first heat exchanger is connected to the inlet of the first circulation pump; the b port of the three-way valve A is connected to the first radiator; the first radiator is connected to the a port of the first heat exchanger.

[0010] Heat is obtained from the heat pump system through the first heat exchanger. When the port a of the three-way valve A is connected to the port c, the obtained heat is transferred to the first radiator, and the passenger compartment can be heated by the blower. When the port a of the three-way valve A is connected to the port c, the obtained heat is transferred to the heater core and dispersed into the atmosphere to ensure the operation of the heat pump system. It should be noted that the port a of the three-way valve A can be connected to only one of the ports c and b, or it can be connected to both ports c and b. At this time, the valve core angle can be adjusted to control the opening of each outlet to achieve a reasonable distribution of the heat generated by the heat pump system.

[0011] Preferably, a first temperature sensor is provided at the inlet of the first circulation pump. Port a and port b of the first heat exchanger are connected.

[0012] Furthermore, a three-way valve B is provided on the connecting pipeline between the heater core and the port a of the first heat exchanger, the port a of the three-way valve B is connected to the heater core, the port b and the port c of the three-way valve B are both connected to the port a of the first heat exchanger, and the port b and the port c of the three-way valve B are both connected to the battery circuit.

[0013] Furthermore, the battery circuit includes a third circulation pump, the outlet of the third circulation pump is connected to the inlet, and the refrigerant between the inlet and the inlet flows through the battery pack and can perform heat exchange with the battery pack; the b port and the c port of the three-way valve B are both connected to the refrigerant outlet of the battery pack.

[0014] Preferably, in the connecting pipeline between the refrigerant outlet of the battery pack and the inlet of the third circulation pump, the b-port connecting point and the c-port connecting point of the three-way valve B are separated, and the b-port connecting point of the three-way valve B is close to the refrigerant outlet of the battery pack, ensuring that the refrigerant flows smoothly in the battery circuit and the first heat transfer circuit.

[0015] Preferably, the battery circuit further includes a second temperature sensor and a third temperature sensor, the second temperature sensor being used to detect the temperature of the refrigerant flowing out of the battery pack, and the third temperature sensor being used to detect the temperature of the refrigerant flowing into the battery pack.

[0016] As another improvement of the R290-based electric vehicle thermal management system of the present invention, the second heat transfer circuit includes a second circulation pump, a cold air core, a blower, the second heat exchanger, a three-way valve C, and a three-way valve D; the outlet of the second circulation pump is connected to the cold air core; the cold air core is connected to the c port of the second heat exchanger; the d port of the second heat exchanger is connected to the a port of the three-way valve C; the b port of the three-way valve C is connected to the inlet of the second circulation pump; the c port of the three-way valve C is connected to the a port of the three-way valve D; the c port of the three-way valve D and the c port of the second heat exchanger are both connected to the electric drive cooling system.

[0017] The second heat exchanger obtains cold energy from the heat pump system, and the obtained cold energy can be transferred to the cold air core to cool the passenger compartment in cooperation with the blower, or the cold energy can be transferred to the second radiator to be dissipated into the atmosphere to ensure the operation of the heat pump system.

[0018] Preferably, port c and port d of the second heat exchanger are connected, and port a and port b are connected.

[0019] Furthermore, a three-way valve E is provided on the connecting pipeline between the cold air core and the c port of the second heat exchanger, the a port of the three-way valve E is connected to the cold air core, the b port is connected to the c port of the second heat exchanger, and the b port and the c port of the three-way valve E and the b port of the three-way valve D are all connected to the battery circuit.

[0020] Furthermore, the electric drive cooling system includes a fourth circulation pump, the second radiator, a three-way valve G and a three-way valve H; the outlet of the fourth circulation pump is connected to the second radiator; the second radiator is connected to the b port of the three-way valve G; the c port of the three-way valve G is connected to the inlet of the second radiator, and the a port is connected to the a port of the three-way valve H; the c port of the three-way valve H is connected to the c port of the second heat exchanger, and the b port is connected to the inlet of the fourth circulation pump; the inlet of the fourth circulation pump is also connected to the c port of the three-way valve D; the refrigerant between the outlet of the fourth circulation pump and the second radiator flows through the electric drive system, and can absorb and take away the heat from the electric drive system.

[0021] Preferably, the electric drive cooling system further includes a fourth temperature sensor, and the fourth temperature sensor is used to detect the temperature of the refrigerant flowing through the electric drive system.

[0022] Furthermore, the battery circuit includes a third circulation pump and a three-way valve F, the outlet of the third circulation pump is connected to the port a of the three-way valve F; the port c of the three-way valve F is connected to the inlet of the third circulation pump and the port b of the three-way valve D, the port b is connected to the port b of the three-way valve E, and the port a is also connected to the port C of the three-way valve E; the refrigerant between the outlet of the third circulation pump and the port a of the three-way valve F flows through the battery pack and can perform heat exchange with the battery pack.

[0023] As another improvement of the R290-based thermal management system for electric vehicles of the present invention, the system further includes an electric heater, which is used to cooperate with the blower to heat the vehicle passenger compartment.

[0024] Preferably, the refrigerant of the first heat transfer circuit, the second heat transfer circuit and the battery circuit may be the same, that is, water.

[0025] In order to solve the above technical problems, the present invention provides, on the other hand, a control method for the above R290-based electric vehicle thermal management system, comprising:

[0026] When it is necessary to cool the battery pack and dissipate heat from the electric drive system at the same time, the control is performed so that: the heat pump system works, the first heat transfer circuit operates, heat is obtained from the heat pump system through the first heat exchanger, and the heat is transferred to the first radiator, the second heat transfer circuit operates, cold is obtained from the heat pump system through the second heat exchanger, and the cold is transferred to the cold air core, the battery circuit operates and is connected to the second heat transfer circuit through a pipeline, so as to cool the battery pack, the fan works, and the blower does not work.

[0027] Furthermore, when it is necessary to cool the passenger compartment, cool the battery pack, and dissipate heat from the electric drive system, the control is performed so that: the heat pump system works, the first heat transfer circuit operates, heat is obtained from the heat pump system through the first heat exchanger, and the heat is transferred to the first radiator, the second heat transfer circuit operates, cold energy is obtained from the heat pump system through the second heat exchanger, and the cold energy is transferred to the cold air core, the battery circuit operates and is connected to the second heat transfer circuit through a pipeline, so as to cool the battery pack, operate the fan, and operate the blower.

[0028] Furthermore, when it is necessary to utilize the waste heat of the electric drive system to heat the passenger compartment and the battery pack, the control is performed so that: the heat pump system works, the first heat transfer circuit obtains heat from the heat pump system through the first heat exchanger, and transfers the heat to the heater core, the battery circuit is connected to the first heat transfer circuit through a pipeline to achieve heating of the battery pack, the electric drive cooling system is connected to the second heat transfer circuit through a pipeline, and the heat of the electric drive system is provided to the heat pump system through the second heat exchanger, the blower works, and the fan does not work.

[0029] Furthermore, when it is necessary to dissipate heat from the electric drive system and dehumidify the passenger compartment at the same time, the control is performed so that: the heat pump system works, the first heat transfer circuit obtains heat from the heat pump system through the first heat exchanger, and transfers the heat to the warm air core, the second heat transfer circuit obtains cold from the heat pump system through the second heat exchanger, and transfers the cold to the cold air core, the electric drive cooling system is connected to the second heat transfer circuit through a pipeline, and the heat of the electric drive system is provided to the heat pump system through the second heat exchanger, the blower works, and the fan does not work.

[0030] In summary, the above R290-based electric vehicle thermal management system and control method have the following beneficial effects:

[0031] 1. Wide temperature range: R290 has a low boiling point and still has strong cooling capacity at high temperatures. It can still maintain a certain COP at low temperatures, thereby improving the endurance of pure electric vehicles.

[0032] 2. Safety: This technical solution simplifies the refrigerant circuit, concentrates R290 in the front cabin of the vehicle, and reduces the refrigerant charge, thereby improving the safety of R290 refrigerant during use.

[0033] 3. This technical solution can recover waste heat from electric drives, improve system energy efficiency, and enhance low-temperature endurance.

[0034] 4. This technical solution can simplify the piping layout of the refrigerant circuit in the front cabin thermal management system and reduce the number of parts. For example, the external condenser, solenoid valve and other components are removed, and the number of solenoid expansion valves is reduced to one. This design reduces the weight of the vehicle and reduces the system cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In the attached picture:

[0036] Figure 1 This is a schematic diagram of the thermal management system for an electric vehicle based on R290 according to the present invention.

[0037] Figure 2 Schematic diagram of refrigerant flow in mode 1 of the control method of the present invention.

[0038] Figure 3 Schematic diagram of refrigerant flow in mode three of the control method of the present invention.

[0039] Figure 4 Schematic diagram of refrigerant flow in mode 4 of the control method of the present invention.

[0040] Figure 5 Schematic diagram of refrigerant flow in mode five of the control method of the present invention.

[0041] In the figure, 1, the first heat exchanger; 2, the compressor; 3, the first circulation pump; 4, the three-way valve A; 5, the three-way valve B; 6, the fan; 7, the liquid storage tank; 8, the blower; 9, the cold air core; 10, the warm air core; 11, the electric heater; 12, the three-way valve E; 13, the battery pack; 14, the first radiator; 15, the second heat exchanger; 16, the expansion valve; 17, the three-way valve C; 18, the second circulation pump; 19, the third circulation pump; 20, the three-way valve G; 21, the three-way valve H; 22, the three-way valve D; 23, the fourth circulation pump; 24, the electric drive system; 25, the first temperature sensor; 26, the first pressure temperature sensor; 27, the second pressure temperature sensor; 28, the second temperature sensor; 29, the third temperature sensor; 30, the three-way valve F; 31, the fourth temperature sensor; 32, the second radiator. DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0043] Example 1

[0044] Figure 1 The present invention shows a thermal management system for electric vehicles based on R290. Figure 1 As shown, the R290-based electric vehicle thermal management system includes a heat pump system, a first heat transfer loop, a second heat transfer loop, a battery loop and an electric drive cooling system; the heat pump system includes a heat pump circulation loop composed of a first heat exchanger 1, a compressor 2, a second heat exchanger 15 and an expansion valve 16, and the refrigerant of the heat pump circulation loop is R290, and the entire heat pump circulation loop is arranged in the front cabin of the vehicle; the first heat transfer loop can obtain heat from the heat pump system through the first heat exchanger 1, and transfer the heat to the first radiator 14 Or the warm air core 10; the second heat transfer circuit can obtain cold energy from the heat pump system through the second heat exchanger 15, and transfer the cold energy to the second radiator 32 or the cold air core 9; the battery circuit is connected to the first heat transfer circuit and the second heat transfer circuit through a pipeline, so as to realize the temperature regulation of the battery pack 13; the electric drive cooling system is connected to the second heat transfer circuit through a pipeline, so as to dissipate the heat of the electric drive system 24 through the second radiator 32, and to provide the heat of the electric drive system 24 to the heat pump system through the second heat exchanger 15.

[0045] The heat pump system also includes a liquid storage tank 7; the outlet of the compressor 2 is connected to the d port of the first heat exchanger 1; the c port of the first heat exchanger 1 is connected to the liquid storage tank (7), the liquid storage tank (7) is connected to the a port of the second heat exchanger 15, and an expansion valve 16 is provided on the connecting pipeline; the b port of the second heat exchanger 15 is connected to the inlet of the compressor 2.

[0046] By placing the liquid storage tank 7 between the compressor 2 and the expansion valve 16, the volume of the refrigerant circuit is further reduced, and the amount of refrigerant charged is reduced. The liquid storage tank 7 can compensate for the refrigerant loss, maintain pressure balance, and increase the subcooling degree before the second heat exchanger 15, i.e., the evaporator. In addition, the superheat at the inlet of the compressor 2 can be controlled to ensure that no liquid enters the compressor 2.

[0047] Optionally, the heat pump system further includes a first pressure and temperature sensor 26 and a second pressure and temperature sensor 27. The first pressure and temperature sensor 26 is used to detect the refrigerant temperature and pressure at the outlet of the compressor 2, and the second pressure and temperature sensor 27 is used to detect the refrigerant temperature and pressure at the inlet of the compressor 2. The normal operation of the entire heat pump system is ensured by detection and monitoring. The c port and the d port of the first heat exchanger 1 are connected.

[0048] The first heat transfer circuit includes a first circulation pump 3, a three-way valve A4, a heater core 10, a blower 8, a first radiator 14 and a first heat exchanger 1; the outlet of the first circulation pump 3 is connected to the port a of the three-way valve A4; the port c of the three-way valve A4 is connected to the heater core 10; the heater core 10 is connected to the port a of the first heat exchanger 1; the port b of the first heat exchanger 1 is connected to the inlet of the first circulation pump 3; the port b of the three-way valve A4 is connected to the first radiator 14; the first radiator 14 is connected to the port a of the first heat exchanger 1.

[0049] Heat is obtained from the heat pump system through the first heat exchanger 1. When the port a of the three-way valve A4 is connected to the port c, the obtained heat is transferred to the first radiator 14. With the help of the blower 8, the passenger compartment can be heated. When the port a of the three-way valve A4 is connected to the port c, the obtained heat is transferred to the heater core 10 and dissipated into the atmosphere to ensure the operation of the heat pump system.

[0050] Optionally, a first temperature sensor 25 is provided at the inlet of the first circulation pump 3. The port a and the port b of the first heat exchanger 1 are connected.

[0051] A three-way valve B5 is provided on the connecting pipeline between the heater core 10 and the port a of the first heat exchanger 1. The port a of the three-way valve B5 is connected to the heater core 10, the ports b and c of the three-way valve B5 are both connected to the port a of the first heat exchanger 1, and the ports b and c of the three-way valve B5 are both connected to the battery circuit.

[0052] Optionally, the battery circuit further includes a second temperature sensor 28 and a third temperature sensor 29 , wherein the second temperature sensor 28 is used to detect the temperature of the refrigerant flowing out of the battery pack 13 , and the third temperature sensor 29 is used to detect the temperature of the refrigerant flowing into the battery pack 13 .

[0053] The second heat transfer circuit includes a second circulation pump 18, a cold air core 9, a blower 8, a second heat exchanger 15, a three-way valve C17, and a three-way valve D22; the outlet of the second circulation pump 18 is connected to the cold air core 9; the cold air core 9 is connected to the c port of the second heat exchanger 15; the d port of the second heat exchanger 15 is connected to the a port of the three-way valve C17; the b port of the three-way valve C17 is connected to the inlet of the second circulation pump 18; the c port of the three-way valve C17 is connected to the a port of the three-way valve D22; the c port of the three-way valve D22 and the c port of the second heat exchanger 15 are both connected to the electric drive cooling system.

[0054] Optionally, port c and port d of the second heat exchanger 15 are connected, and port a and port b are connected.

[0055] A three-way valve E12 is provided on the connecting pipeline between the cold air core 9 and the c port of the second heat exchanger 15. The a port of the three-way valve E12 is connected to the cold air core 9, and the b port is connected to the c port of the second heat exchanger 15. The b port and the c port of the three-way valve E12 and the b port of the three-way valve D22 are all connected to the battery circuit.

[0056] The electric drive cooling system includes a fourth circulation pump 23, a second radiator 32, a three-way valve G20 and a three-way valve H21; the outlet of the fourth circulation pump 23 is connected to the second radiator 32; the second radiator 32 is connected to the b port of the three-way valve G20; the c port of the three-way valve G20 is connected to the inlet of the second radiator 32, and the a port is connected to the a port of the three-way valve H21; the c port of the three-way valve H21 is connected to the c port of the second heat exchanger 15, and the b port is connected to the inlet of the fourth circulation pump 23; the inlet of the fourth circulation pump 23 is also connected to the c port of the three-way valve D22; the refrigerant between the outlet of the fourth circulation pump 23 and the second radiator 32 flows through the electric drive system 24, and can absorb and take away the heat at the electric drive system 24.

[0057] Optionally, the electric drive cooling system further includes a fourth temperature sensor 31 , which is used to detect the temperature of the refrigerant flowing through the electric drive system 24 .

[0058] The battery circuit includes a third circulation pump 19 and a three-way valve F30, the outlet of the third circulation pump 19 is connected to the port a of the three-way valve F30; the port c of the three-way valve F30 is connected to the inlet of the third circulation pump 19 and the port b of the three-way valve D22, the port b is connected to the port b of the three-way valve E12, and the port a is also connected to the port C of the three-way valve E12; the refrigerant between the outlet of the third circulation pump 19 and the port a of the three-way valve F30 flows through the battery pack 13 and can perform heat exchange with the battery pack 13.

[0059] In addition, the b port and the c port of the three-way valve B5 are both connected to the refrigerant outlet of the battery pack 13, and in the connecting pipeline between the refrigerant outlet of the battery pack 13 and the inlet of the third circulation pump 19, the b port connection point of the three-way valve B5 is separated from the c port connection point, and the b port connection point of the three-way valve B5 is close to the refrigerant outlet of the battery pack 13, ensuring that the refrigerant flows smoothly in the battery circuit and the first heat transfer circuit.

[0060] The system further includes an electric heater 11, which is used to heat the vehicle passenger compartment in cooperation with the blower 8. The electric heater 11 may be a high-pressure air PTC (Positive Temperature Coefficient, which is an existing heating technology that generates heat by electricity).

[0061] Optionally, the refrigerant of the first heat transfer loop, the second heat transfer loop and the battery loop may all be water. The system further includes a fan 6, which can blow air to the first radiator 14 and the second radiator 32 to improve the heat dissipation efficiency.

[0062] Example 2

[0063] The present invention provides a control method for the above-mentioned R290-based electric vehicle thermal management system. By controlling the working state of each component, the entire system can be in different working modes. In order to enable relevant personnel in the technical field to better understand the present invention, five working modes of the whole vehicle thermal management system based on R290 under different typical working conditions will be introduced below. It is worth pointing out that the described working mode principle is only a part of the working conditions of the present invention, not all working conditions. Other working conditions based on the present invention obtained by ordinary technicians in this field without making creative work should belong to the protection scope of the present invention. The electric drive system 24 of the present invention mainly includes components such as motors and motor controllers, and does not include battery packs 13.

[0064] First, the working process of the heat pump system is introduced. Like conventional heat pump technology, it is a heat transfer process based on thermodynamic principles, and its core lies in achieving heat transfer through the reverse Carnot cycle. When the heat pump system is working, the refrigerant circulation path is: compressor 2-first heat exchanger 1-expansion valve 16-second heat exchanger 15-compressor 2; compressor 2 compresses the refrigerant gas, causing its pressure and temperature to increase significantly, and this process consumes electrical energy; the first heat exchanger 1 releases the refrigerant heat to the refrigerant in the first heat transfer circuit to achieve heating; the expansion valve 16 (or throttle valve) reduces the pressure and temperature of the refrigerant, and it has the ability to absorb heat and evaporate again; in the second heat exchanger 15, the refrigerant R290 evaporates and absorbs heat from the refrigerant in the surrounding second heat transfer circuit, causing the refrigerant temperature in the second heat transfer circuit to drop, achieving refrigeration.

[0065] Mode 1: Under normal temperature conditions, the battery pack 13 is cooled while the electric drive system 24 is cooled; Figure 2 As shown in the figure, the specific control process is:

[0066] ①The heat pump system works, and the working process will not be described in detail;

[0067] ② The first heat transfer loop operates, obtains heat from the heat pump system through the first heat exchanger 1, and transfers the heat to the first radiator 14;

[0068] The first circulation pump 3 is working, the ports a and b of the three-way valve A4 are connected (ports a and c are disconnected), and the fan 6 is working; the refrigerant flow path of the first heat transfer circuit is: the first circulation pump 3-port a of the three-way valve A4-port b of the three-way valve A4-first radiator 14-port a of the first heat exchanger 1-port b of the first heat exchanger 1-first circulation pump 3, circulating;

[0069] ③ The second heat transfer loop operates, obtains cold energy from the heat pump system through the second heat exchanger 15, and transfers the cold energy to the cold air core 9; and the battery loop operates to connect the second heat transfer loop through the pipeline to achieve cooling of the battery pack 13

[0070] The second circulation pump 18 and the third circulation pump 19 are working, the port a and the port c of the three-way valve E12 are connected (the port a and the port b are disconnected), the port a and the port c of the three-way valve F30 are connected and the port a and the port b are also connected, the port a and the port b of the three-way valve C17 are connected (the port a and the port c are disconnected), and the three-way valve D22 is in the closed state; the blower 8 is not working;

[0071] The refrigerant flow path of the second heat transfer circuit and the battery circuit is: second circulation pump 18-cold air core 9-port a of three-way valve E12-port c of three-way valve E12-port a of three-way valve F30, and then the refrigerant flowing out from port b of the three-way valve F30 flows through port c of the second heat exchanger 15, port d of the second heat exchanger 15, port a of the three-way valve C17, port b of the three-way valve C17, and finally returns to the second circulation pump 18 to realize circulation flow; the refrigerant flowing out from port c of the three-way valve F30 flows through the third circulation pump 19 and the battery pack 13, and finally returns to port a of the three-way valve F30 for circulation flow.

[0072] ④ The electric drive cooling circuit operates to achieve heat dissipation of the electric drive system 24

[0073] When the fourth circulation pump 23 is working, the b port and the a port of the three-way valve G20 are connected (the c port and the a port are disconnected), and the a port and the b port of the three-way valve H21 are connected (the a port and the c port are disconnected); the refrigerant flow path of the electric drive cooling system is: the fourth circulation pump 23-electric drive system 24-the second radiator 32-the b port of the three-way valve G20-the a port of the three-way valve G20-the a port of the three-way valve H21-the b port of the three-way valve H21-the fourth circulation pump 23.

[0074] The cooling water is driven by the second circulating pump 18, and the heat is absorbed by the refrigerant evaporation on the water side of the second heat exchanger 15, and then enters the cold air core 9 and the battery pack water cooling plate (the blower 8 is not working and the passenger compartment is not refrigerated) to cool the battery. The fourth circulating pump 23 drives the cooling water to flow through the electric drive system 24 and the second radiator 32 to achieve electric drive heat dissipation. The refrigerant absorbs heat and evaporates in the second heat exchanger 15 to become a gaseous refrigerant, which is converted into a high-temperature and high-pressure gaseous refrigerant by the electric compressor 2, and then condenses and releases heat in the first heat exchanger 1. The cooling water on the water side of the first heat exchanger 1 absorbs heat and flows through the first radiator 14 driven by the first circulating pump 3. In summary, under normal temperature conditions, the battery pack 13 is cooled while the electric drive system 24 is cooled.

[0075] Mode 2: Under high temperature conditions, the passenger compartment is cooled, the battery pack 13 is cooled, and the electric drive system 24 is cooled. The specific control working process is compared with the control working state of mode 1, and the difference is only that the blower 8 is turned on to cool the passenger compartment. The circulation path of the refrigerant is as follows: Figure 2 shown.

[0076] Mode 3: Under low temperature conditions, the residual heat of the electric drive system 24 is used to heat the passenger compartment and the battery pack 13; Figure 3 As shown in the figure, the specific control process is:

[0077] ①The heat pump system works;

[0078] ② The first heat transfer loop obtains heat from the heat pump system through the first heat exchanger 1 and transfers the heat to the heater core 10; at the same time, the battery loop is connected to the first heat transfer loop through a pipeline to heat the battery pack 13;

[0079] The blower 8 is working, the first circulation pump 3 is working, the third circulation pump 19 is working, the port a and the port c of the three-way valve A4 are connected (the port a and the port b are disconnected), the port a and the port b of the three-way valve B5 are connected and the port a and the port c are also connected (the opening size of each outlet when connected at the same time can be set), the port a and the port c of the three-way valve F30 are connected (the port a and the port b are disconnected);

[0080] The refrigerant flow path of the first heat transfer circuit and the battery circuit is: the first circulation pump 3 - the a port of the three-way valve A4 - the c port of the three-way valve A4 - the warm air core 10 - the a port of the three-way valve B5, and then the refrigerant flowing out from the b port of the three-way valve B5 flows through the a port of the first heat exchanger 1, the b port of the first heat exchanger 1, and finally returns to the first circulation pump 3 to realize the circulation flow; the refrigerant flowing out from the c port of the three-way valve B5 flows through the a port of the three-way valve F30, the c port of the three-way valve F30, the third circulation pump 19, the battery pack 13, and finally merges with the refrigerant flowing out from the b port of the three-way valve B5 to circulate.

[0081] ③ The electric drive cooling system is connected to the second heat transfer circuit through a pipeline, and the heat of the electric drive system 24 is provided to the heat pump system through the second heat exchanger 15;

[0082] The second circulation pump 18 does not work, the three-way valve E12 is in a closed state, the blower 8 does not work, the fan 6 does not work, the fourth circulation pump 23 works, the port a of the three-way valve C17 is connected to the port c (the port a is disconnected from the port b), the port a of the three-way valve D22 is connected to the port c (the port a is disconnected from the port b), the port a of the three-way valve H21 is connected to the port c (the port a is disconnected from the port b), and the port a of the three-way valve G20 is connected to the port c (the port a is disconnected from the port b);

[0083] The refrigerant flow path of the second heat transfer circuit and the electric drive cooling system is: the fourth circulation pump 23-electric drive system 24-port c of three-way valve G20-port a of three-way valve G20-port a of three-way valve H21-port c of three-way valve H21-port c of the second heat exchanger 15-port d of the second heat exchanger 15-port a of three-way valve C17-port c of three-way valve C17-port a of three-way valve D22-port c of three-way valve D22-fourth circulation pump 23.

[0084] This usage scenario is usually a low-temperature condition, and the refrigerant is usually cooling water. The cooling water is driven by the first circulating pump 3, absorbs the heat released by the condensation of the refrigerant on the water side of the first heat exchanger 1, and then enters the heater core 10. The blower 8 transports the air to the heater core 10 for heating to achieve heating of the passenger compartment. The cooling water is then divided into two paths, one flows back to the first heat exchanger 1 to absorb heat, and the other flows through the battery pack 13, usually into the battery pack cold plate to heat the battery pack 13. Driven by the fourth circulating pump 23, the cooling water flows through the electric drive system 24, absorbs the waste heat of the electric drive and transfers it to the refrigerant in the second heat exchanger 15, realizing the waste heat utilization of the electric drive.

[0085] Mode 4: Defrosting mode under low temperature conditions

[0086] like Figure 4 As shown in the figure, the specific control process is:

[0087] ①The heat pump system does not work;

[0088] ② The refrigerants in the first heat transfer circuit, the second heat transfer circuit and the battery circuit flow evenly, the first circulation pump 3, the second circulation pump 18 and the third circulation pump 19 do not work, and the three-way valves are closed.

[0089] ③ The electrically driven cooling system operates alone, the fan 6 works, the fourth circulating pump 23 works, the port a and the port b of the three-way valve G20 are connected (the port a and the port c are disconnected), the port a and the port b of the three-way valve H21 are connected (the port a and the port c are disconnected), and the refrigerant flow path of the electrically driven cooling system is: the fourth circulating pump 23-electric drive system 24-the second radiator 32-the port b of the three-way valve G20-the port a of the three-way valve G20-the port a of the three-way valve H21-the port b of the three-way valve H21-the fourth circulating pump 23.

[0090] This usage scenario is usually when the outside environment temperature is low and the outdoor heat exchanger is prone to frost. If the radiator is frosted, the system performance will drop sharply. At this time, defrosting is achieved by "transferring" the heat of the electric drive system 24 to the radiator. When designing, the airflow generated by the fan 6 can flow through the second radiator 32 first and then through the first radiator 14, so that the two radiators can be defrosted at the same time.

[0091] Mode 5: Dehumidification condition, dissipating heat from the electric drive system 24 and dehumidifying the passenger compartment at the same time

[0092] like Figure 5 As shown in the figure, the specific control process is:

[0093] ①The heat pump system works;

[0094] ② The first heat transfer loop obtains heat from the heat pump system through the first heat exchanger 1 and transfers the heat to the heater core 10.

[0095] The blower 8 is working, the first circulating pump 3 is working, the third circulating pump 19 is not working, the port a and the port c of the three-way valve A4 are connected (the port a and the port b are disconnected), and the port a and the port b of the three-way valve B5 are connected (the port a and the port c are disconnected);

[0096] The refrigerant flow path of the first heat transfer circuit is: first circulation pump 3 - port a of three-way valve A4 - port c of three-way valve A4 - warm air core 10 - port a of three-way valve B5 - port b of three-way valve B5 - port a of the first heat exchanger 1 - port b of the first heat exchanger 1 - first circulation pump 3, to achieve circulation flow.

[0097] ③ The second heat transfer loop obtains cold energy from the heat pump system through the second heat exchanger 15, and transfers the cold energy to the cold air core 9; the electric drive cooling system is connected to the second heat transfer loop through a pipeline, and provides the heat of the electric drive system 24 to the heat pump system through the second heat exchanger 15;

[0098] The second circulation pump 18 is working, the port a and the port b of the three-way valve E12 are connected (the port a and the port c are disconnected), the three-way valve F30 is closed, the blower 8 is working, the fan 6 is not working, the fourth circulation pump 23 is working, the port a and the port c of the three-way valve C17 are connected and the port a and the port b are also connected, the port a and the port c of the three-way valve D22 are connected (the port a and the port b are disconnected), the port a and the port c of the three-way valve H21 are connected (the port a and the port b are disconnected), and the port a and the port c of the three-way valve G20 are connected (the port a and the port b are disconnected);

[0099] The refrigerant flow path of the second heat transfer circuit and the electric drive cooling system is: the fourth circulation pump 23-electric drive system 24-port c of the three-way valve G20-port a of the three-way valve G20-port a of the three-way valve H21-port c of the three-way valve H21-port c of the second heat exchanger 15-port d of the second heat exchanger 15-port a of the three-way valve C17, and then the refrigerant flowing out of port c of the three-way valve C17 flows through port a of the three-way valve D22 and port c of the three-way valve D22, and finally returns to the fourth circulation pump 23 to realize the circulation flow; the refrigerant flowing out of port b of the three-way valve C17 flows through the second circulation pump 18, the cold air core 9, port a of the three-way valve E12, and port b of the three-way valve E12, and finally merges with the refrigerant flowing out of port c of the three-way valve H21 to circulate.

[0100] The blower 8 delivers air to the cold air core 9 for cooling, condenses water, and reduces the moisture content of the air. The air is then heated by the warm air core 10. The relative humidity of the heated air is significantly reduced, achieving a dehumidification function and improving the comfort of the passengers.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

Claims

1. A thermal management system for electric vehicles based on R290, characterized in that: including a heat pump system, a first heat transfer loop, a second heat transfer loop, a battery loop, and an electric drive cooling system; The heat pump system comprises a heat pump circulation loop consisting of a first heat exchanger (1), a compressor (2), a second heat exchanger (15) and an expansion valve (16), wherein the refrigerant of the heat pump circulation loop is R290, and the entire heat pump circulation loop is arranged in the front cabin of the vehicle; The first heat transfer circuit can obtain heat from the heat pump system through the first heat exchanger (1) and transfer the heat to the first radiator (14) or the heater core (10); The second heat transfer circuit can obtain cold energy from the heat pump system through the second heat exchanger (15), and transfer the cold energy to the second radiator (32) or the cold air core (9); The battery circuit is connected to the first heat transfer circuit and the second heat transfer circuit via a pipeline, so as to achieve temperature regulation of the battery pack (13); The electric drive cooling system is connected to the second heat transfer circuit via a pipeline, and can dissipate the heat of the electric drive system (24) through the second radiator (32), and can also provide the heat of the electric drive system (24) to the heat pump system through the second heat exchanger (15).

2. According to claim 1, a thermal management system for electric vehicles based on R290 is characterized in that: The heat pump system also includes a liquid storage tank (7); The outlet of the compressor (2) is connected to the port d of the first heat exchanger (1); the port c of the first heat exchanger (1) is connected to the liquid storage tank (7), the liquid storage tank (7) is connected to the port a of the second heat exchanger (15), and the expansion valve (16) is provided on the connecting pipeline; the port b of the second heat exchanger (15) is connected to the inlet of the compressor (2).

3. The R290-based electric vehicle thermal management system according to claim 1, characterized in that: The first heat transfer circuit comprises a first circulation pump (3), a three-way valve A (4), the heater core (10), a blower (8), a first radiator (14) and a first heat exchanger (1); The outlet of the first circulation pump (3) is connected to the port a of the three-way valve A (4); the port c of the three-way valve A (4) is connected to the heater core (10); the heater core (10) is connected to the port a of the first heat exchanger (1); the port b of the first heat exchanger (1) is connected to the inlet of the first circulation pump (3); the port b of the three-way valve A (4) is connected to the first radiator (14); the first radiator (14) is connected to the port a of the first heat exchanger (1).

4. The R290-based electric vehicle thermal management system according to claim 3 is characterized in that: A three-way valve B (5) is provided on the connecting pipeline between the heater core (10) and the port a of the first heat exchanger (1); the port a of the three-way valve B (5) is connected to the heater core (10); the ports b and c of the three-way valve B (5) are both connected to the port a of the first heat exchanger (1); and the ports b and c of the three-way valve B (5) are both connected to the battery circuit.

5. The R290-based electric vehicle thermal management system according to claim 4 is characterized in that: The battery circuit comprises a third circulation pump (19), the outlet of the third circulation pump (19) is connected to the inlet, and the refrigerant between the inlet and the inlet flows through the battery pack (13) and can perform heat exchange with the battery pack (13); the port b and the port c of the three-way valve B (5) are both connected to the refrigerant outlet of the battery pack (13).

6. The R290-based electric vehicle thermal management system according to claim 1, characterized in that: The second heat transfer circuit comprises a second circulation pump (18), a cold air core (9), a blower (8), the second heat exchanger (15), a three-way valve C (17), and a three-way valve D (22); The outlet of the second circulation pump (18) is connected to the cold air core (9); the cold air core (9) is connected to the c port of the second heat exchanger (15); the d port of the second heat exchanger (15) is connected to the a port of the three-way valve C (17); the b port of the three-way valve C (17) is connected to the inlet of the second circulation pump (18); the c port of the three-way valve C (17) is connected to the a port of the three-way valve D (22); the c port of the three-way valve D (22) and the c port of the second heat exchanger (15) are both connected to the electrically driven cooling system.

7. The R290-based electric vehicle thermal management system according to claim 6 is characterized in that: A three-way valve E (12) is provided on the connecting pipeline between the cold air core (9) and the c port of the second heat exchanger (15); the a port of the three-way valve E (12) is connected to the cold air core (9), and the b port is connected to the c port of the second heat exchanger (15); the b port and the c port of the three-way valve E (12) and the b port of the three-way valve D (22) are all connected to the battery circuit.

8. The R290-based electric vehicle thermal management system according to claim 6 is characterized in that: The electrically driven cooling system comprises a fourth circulation pump (23), the second radiator (32), a three-way valve G (20) and a three-way valve H (21); the outlet of the fourth circulation pump (23) is connected to the second radiator (32); the second radiator (32) is connected to the port b of the three-way valve G (20); the port c of the three-way valve G (20) is connected to the inlet of the second radiator (32), and the port a is connected to the port a of the three-way valve H (21); the port c of the three-way valve H (21) is connected to the port c of the second heat exchanger (15), and the port b is connected to the inlet of the fourth circulation pump (23); the inlet of the fourth circulation pump (23) is also connected to the port c of the three-way valve D (22); The refrigerant between the outlet of the fourth circulation pump (23) and the second radiator (32) flows through the electric drive system (24), and can absorb and take away the heat at the electric drive system (24).

9. The R290-based electric vehicle thermal management system according to claim 6, characterized in that: The battery circuit comprises a third circulation pump (19) and a three-way valve F (30), wherein the outlet of the third circulation pump (19) is connected to the port a of the three-way valve F (30); the port c of the three-way valve F (30) is connected to the inlet of the third circulation pump (19) and the port b of the three-way valve D (22); the port b is connected to the port b of the three-way valve E (12); and the port a is also connected to the port C of the three-way valve E (12); The refrigerant between the outlet of the third circulation pump (19) and the port a of the three-way valve F (30) flows through the battery pack (13) and can perform heat exchange with the battery pack (13).

10. The R290-based electric vehicle thermal management system according to claim 1, characterized in that: It also includes an electric heater (11), which is used to cooperate with the blower (8) to heat the vehicle passenger compartment.

11. A control method for an electric vehicle thermal management system based on R290 as claimed in any one of claims 1 to 10, characterized in that: include: When it is necessary to cool the battery pack (13) and dissipate heat from the electric drive system (24) at the same time, the control is performed so that: the heat pump system operates, the first heat transfer circuit operates, heat is obtained from the heat pump system through the first heat exchanger (1), and the heat is transferred to the first radiator (14), the second heat transfer circuit operates, cold energy is obtained from the heat pump system through the second heat exchanger (15), and the cold energy is transferred to the cold air core (9), the battery circuit operates and is connected to the second heat transfer circuit through a pipeline, so as to cool the battery pack (13), the fan (6) operates, and the blower (8) does not operate.

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