Vehicle thermal management system and control method of submersion type battery liquid cooling coupled with air conditioner

Abstract

The vehicle thermal management system coupled by the submerged battery liquid cooling and air conditioner comprises an in-vehicle air conditioning system and a submerged battery liquid cooling system, the submerged battery liquid cooling system comprises a working area, a liquid cooling heat exchanger, a heater, a liquid cooling system vehicle external heat exchanger and a pump. The in-vehicle air conditioning system comprises a compressor, a four-way reversing valve, an air conditioning vehicle internal heat exchange device, a throttling device, an air conditioning vehicle external heat exchanger, a first three-way valve, a second three-way valve, a third three-way valve and an electric valve. The air conditioning vehicle internal heat exchange device, the throttling device and the air conditioning vehicle external heat exchanger are connected in sequence, the air conditioning vehicle internal heat exchange device, the air conditioning vehicle external heat exchanger and the compressor are connected with the four-way reversing valve, and the in-vehicle air conditioning system and the submerged battery liquid cooling system exchange heat through the liquid cooling heat exchanger 22 under some working conditions. The heat exchange through the liquid cooling heat exchanger is coupled, so that the temperature of the power battery is maintained within a specific temperature range, and meanwhile, the energy utilization rate is high and the driving range is good.

Description

Technical Field

[0001] This invention relates to the field of automotive thermal management technology, and in particular to an automotive thermal management system and control method that couples immersion battery liquid cooling with air conditioning. Background Technology

[0002] As the heart of an electric vehicle, the power battery determines the vehicle's driving range and operational stability, attracting significant attention and focused research from major automakers worldwide. Furthermore, the temperature control of the power battery plays a crucial role in the development of electric vehicles.

[0003] The optimal operating temperature for power batteries is between 15℃ and 35℃. Temperatures that are too high or too low can significantly impact battery performance. When the battery pack temperature is too high: 1) Safety is reduced. High temperatures accelerate internal oxidation-reduction reactions, increasing the risk of battery runaway and fire, leading to safety accidents; 2) Performance is weakened and lifespan is shortened. High temperatures accelerate the decomposition and loss of active battery materials, resulting in capacity decay and a significant reduction in cycle life. When the battery pack temperature is too low: 1) Capacity and efficiency are reduced. Low temperatures decrease the activity of polar materials in the electrodes, weakening ion migration dynamics and significantly reducing usable capacity. Simultaneously, low temperatures increase internal resistance, causing more energy to dissipate as heat, reducing overall efficiency; 2) Lifespan is affected. At low temperatures, the chemical reaction rate during charging and discharging slows down, and dissolution and precipitation occur on the electrode surface. Long-term operation can damage the battery and affect its lifespan. Analysis of the test vehicle results published by China Electric Vehicle Test (EV-Test) in the past two years shows that many electric vehicle models experience a 30% reduction in range at low temperatures. This is mainly because some of the battery energy is used for heating in the vehicle's air conditioning system at low temperatures, and the battery's deviation from its ideal operating temperature leads to a decrease in output energy.

[0004] Therefore, closely monitoring and managing the battery pack temperature to ensure it operates within its optimal operating temperature range is crucial for guaranteeing battery performance and lifespan.

[0005] Current mature conventional battery cooling systems, such as air cooling and plate cooling, suffer from low cooling efficiency and poor temperature uniformity.

[0006] After researching electric vehicle battery packs, the applicant found that the main challenges of electric vehicle thermal management systems are: 1. The power batteries in electric vehicles have poor temperature uniformity. Conventional battery thermal management often results in localized excessively high or low temperatures, while battery thermal management systems often respond based on temperature data collected from specific areas, leading to less than ideal overall battery thermal management; 2. Electric vehicles have limited space, and adopting a complex thermal management system for the battery often creates a conflict with the space requirements of the electric vehicle; 3. The energy storage of the electric vehicle's power battery is used independently for PTC electric heating and the vehicle's air conditioning system, resulting in low combined energy efficiency and significantly impacting the driving range. Summary of the Invention

[0007] In order to control the temperature and temperature difference of the power battery within a suitable range, while improving the cooling and heating efficiency, thereby increasing the driving range of the vehicle, and without occupying too much space, this invention provides an automotive thermal management system that couples immersion battery liquid cooling with air conditioning.

[0008] A vehicle thermal management system coupling immersion battery liquid cooling and air conditioning includes an in-vehicle air conditioning system and an immersion battery liquid cooling system. The immersion battery liquid cooling system includes a working area and a liquid cooling heat exchanger. A battery pack can be placed in the working area, and the working liquid within the working area keeps the battery pack submerged. The working liquid can absorb or release heat from the battery pack. The in-vehicle air conditioning system includes a compressor, a four-way reversing valve, an in-vehicle air conditioning heat exchange device, a throttling device, and an out-of-vehicle air conditioning heat exchanger. The in-vehicle air conditioning heat exchange device, the throttling device, and the out-of-vehicle air conditioning heat exchanger are connected sequentially. The in-vehicle air conditioning heat exchanger, the out-of-vehicle air conditioning heat exchanger, and the compressor are connected to the four-way reversing valve. The in-vehicle air conditioning system includes a coupling branch and a waste heat recovery branch. The coupling branch is connected in parallel with the in-vehicle air conditioning heat exchange device, and the waste heat recovery branch is connected in parallel with the out-of-vehicle air conditioning heat exchanger. The vehicle thermal management system coupling immersion battery liquid cooling and air conditioning... The thermal management system includes four states: low-temperature cold start, dual heating, vehicle cabin heating and battery cooling, dual cooling isolated, and dual cooling coupled. In the low-temperature cold start state, the vehicle's air conditioning system does not provide heat to the vehicle cabin but provides heat to the battery pack via a liquid-cooled heat exchanger. In the dual heating state, the vehicle's air conditioning system provides heat to both the vehicle cabin and the battery pack via the liquid-cooled heat exchanger. In the vehicle cabin heating and battery cooling state, the vehicle's air conditioning system provides heat to the vehicle cabin and cooling to the battery pack. In the dual cooling isolated state, the vehicle's air conditioning system provides neither heat nor cooling to the battery pack. In the dual cooling coupled state, the vehicle's air conditioning system provides cooling to both the vehicle cabin and the battery pack via the liquid-cooled heat exchanger. In these states, the refrigerant in the vehicle's air conditioning system can flow through the liquid-cooled heat exchanger via the coupled branch or the waste heat recovery branch. In this way, the use of an immersion liquid cooling system allows the temperature and temperature difference of the power battery to be controlled within a suitable range. At the same time, through the setting of coupling branches and waste heat recovery branches, heat exchange between the vehicle's air conditioning system and the immersion battery liquid cooling system is realized, improving cooling and heating efficiency, thereby increasing the vehicle's driving range. Furthermore, there is no need to set up two separate compression refrigeration cycle systems, which improves the space utilization of the vehicle. It also has low-temperature cold start mode, dual heating mode, vehicle compartment heating and battery cooling mode, dual cooling isolated mode, and dual cooling coupled mode to cope with different operating conditions, thereby improving comfort and corresponding efficiency.

[0009] Furthermore, the in-vehicle air conditioning heat exchange device includes an in-vehicle evaporator and an in-vehicle condenser. The in-vehicle evaporator is connected in parallel with an evaporator valve-controlled bypass branch, and the in-vehicle condenser is connected in parallel with a condenser valve-controlled bypass branch. In the dual heating state and the vehicle compartment heating battery cooling state, the evaporator valve-controlled bypass branch is open, and the condenser valve-controlled bypass branch is closed. The refrigerant of the in-vehicle air conditioning system bypasses the in-vehicle evaporator through the evaporator valve-controlled bypass branch, and simultaneously, the refrigerant of the in-vehicle air conditioning system flows through the in-vehicle condenser. In the dual cooling isolated state and the dual cooling coupled state, the condenser valve-controlled bypass branch is open, and the evaporator valve-controlled bypass branch is closed. The refrigerant of the in-vehicle air conditioning system bypasses the in-vehicle condenser through the condenser valve-controlled bypass branch, and simultaneously, the refrigerant of the in-vehicle air conditioning system flows through the in-vehicle evaporator. Using different heat exchangers to perform evaporation and condensation functions separately can improve the efficiency of the entire system.

[0010] Furthermore, the immersion battery liquid cooling system includes an external heat exchanger for the liquid cooling system and a pump; the pump, the external heat exchanger for the liquid cooling system, the liquid cooling heat exchanger, and the working area are connected in sequence; the external heat exchanger for the liquid cooling system is connected to a valve-controlled bypass branch in parallel. In the low-temperature cold start state, the dual heating state, and the vehicle compartment heating battery cooling state, the valve-controlled bypass branch of the heat exchanger is opened, and the working liquid in the immersion battery liquid cooling system bypasses the external heat exchanger for the liquid cooling system through the valve-controlled bypass branch of the heat exchanger.

[0011] Furthermore, the immersion battery liquid cooling system includes a heater, which is positioned between the pump and the liquid cooling heat exchanger. The heater is connected in parallel to a heater valve-controlled bypass branch. In the dual heating state, the vehicle compartment heating battery cooling state, the dual cooling isolated state, and the dual cooling coupled state, the heater valve-controlled bypass branch is opened, allowing the working liquid in the immersion battery liquid cooling system to bypass the heater through the heater valve-controlled bypass branch. In the low-temperature cold start state, the heater can assist in heating, accelerating the battery's temperature rise.

[0012] Furthermore, the in-vehicle air conditioning system includes a first three-way valve, a second three-way valve, a third three-way valve, and an electric valve. These valves control the refrigerant flow direction and state in the coupling branch or waste heat recovery branch. The liquid-cooled heat exchanger has a first port and a second port. The first three-way valve is located between the four-way reversing valve and the in-vehicle air conditioning heat exchange device, with its other port connected to the first port of the liquid-cooled heat exchanger. The second three-way valve is located between the throttling device and the in-vehicle air conditioning heat exchanger, with its other port connected to the second port of the liquid-cooled heat exchanger. The third three-way valve is located between the in-vehicle air conditioning heat exchanger and the four-way reversing valve, with its other port connected to the first port of the liquid-cooled heat exchanger. One port of the electric valve is connected to the wiring between the throttling device and the in-vehicle air conditioning heat exchange device, and its other end is connected to the second port of the liquid-cooled heat exchanger. Control is convenient by using a three-way valve and an electric valve. Furthermore, the working fluid of the immersion battery liquid cooling system is a fluorinated liquid, mineral oil, or silicone oil.

[0013] This invention provides a control method for a vehicle thermal management system that couples immersion battery liquid cooling with air conditioning. It defines the pipes passing through the in-vehicle heat exchange device of the air conditioning system as the cabin heat exchange branch, and the pipes passing through the external heat exchanger of the air conditioning system as the external heat exchange branch. Specifically, it includes the following state settings:

[0014] Low-temperature cold start state: Control the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve to keep the coupling branch in a flowing state, the vehicle compartment heat exchange branch in a non-flowing state, the vehicle exterior heat exchange branch in a flowing state, and the waste heat recovery branch in a non-flowing state; allow the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve to flow sequentially into the liquid-cooled heat exchanger, the throttling device, and the air-conditioning vehicle exterior heat exchanger, and then flow back to the compressor through the four-way reversing valve; the working liquid in the immersion battery liquid cooling system is pressurized by the pump, flows into the heater through the valve-controlled bypass branch of the heat exchanger, then flows into the liquid-cooled heat exchanger, and then enters the working area to heat the battery pack;

[0015] Dual heating mode: Controlling the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve ensures that the coupling branch is in a flowing state, the vehicle compartment heat exchange branch is in a flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve is diverted by the first three-way valve, with one part flowing through the liquid-cooled heat exchanger to heat the working liquid in the submerged battery liquid cooling system, and the other part flowing through the air-conditioning vehicle interior heat exchange device to heat the vehicle compartment. After heat exchange, the two refrigerant streams merge and then flow through the throttling device, the air-conditioning vehicle exterior heat exchanger, and the four-way reversing valve before flowing into the compressor; the working liquid in the submerged battery liquid cooling system is pressurized by the pump and flows into the liquid-cooled heat exchanger through the heat exchanger valve-controlled bypass branch and the heater valve-controlled bypass branch before entering the working area to heat the battery pack;

[0016] Cooling status of the vehicle compartment heating battery: Controlling the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve to keep the coupling branch in a non-flowing state, the vehicle compartment heat exchange branch in a flowing state, the vehicle exterior heat exchange branch in a non-flowing state, and the waste heat recovery branch in a flowing state; allowing the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve to sequentially flow into the air-conditioning vehicle interior heat exchange device, the throttling device, and the liquid-cooled heat exchanger, and then flow into the compressor after passing through the four-way reversing valve; the working liquid in the immersion battery liquid cooling system, after being pressurized by the pump, flows into the liquid-cooled heat exchanger through the heat exchanger valve-controlled bypass branch and the heater valve-controlled bypass branch before entering the working area to heat the battery pack;

[0017] Dual refrigeration isolated state: Controlling the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve, so that the coupling branch is in a non-flowing state, the vehicle compartment heat exchange branch is in a flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve flows sequentially through the air conditioning vehicle exterior heat exchanger, the throttling device, and the air conditioning vehicle interior heat exchanger, and then flows into the compressor through the four-way reversing valve; the working liquid in the immersion battery liquid cooling system is pressurized by the pump and flows into the liquid cooling system vehicle exterior heat exchanger, then into the heater valve-controlled bypass branch, then into the liquid cooling heat exchanger, and then into the working area to cool the battery pack;

[0018] Dual refrigeration coupling state: Controlling the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve ensures that the coupling branch is in a flowing state, the vehicle compartment heat exchange branch is in a flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve flows sequentially through the air conditioning vehicle exterior heat exchanger and the throttling device. The refrigerant flowing out of the throttling device is split, with one part flowing into the air conditioning vehicle interior heat exchanger and the other part flowing through the liquid-cooled heat exchanger. After being combined through the first three-way valve, it flows into the compressor through the four-way reversing valve; the working liquid in the immersion battery liquid cooling system is pressurized by the pump and flows into the liquid cooling system vehicle exterior heat exchanger. The working liquid flowing out of the liquid cooling system vehicle exterior heat exchanger flows into the liquid cooling heat exchanger through the heater valve-controlled bypass branch. After the working liquid gains cooling, it enters the working area to cool the battery pack. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a coupled vehicle management system according to the present invention.

[0020] Figure 2 yes Figure 1 The diagram shows the system operation of the coupled vehicle management system in a low-temperature cold start state.

[0021] Figure 3 yes Figure 1 The diagram shows the system operation of the coupled vehicle management system in a dual-heating state.

[0022] Figure 4 yes Figure 1 The diagram shows the system operation of the coupled vehicle management system in the vehicle compartment heating and battery cooling state.

[0023] Figure 5 yes Figure 1 The diagram shows the system operation of the coupled vehicle management system in a dual-cooling isolated state.

[0024] Figure 6 yes Figure 1 The diagram shows the system operation of the coupled vehicle management system in a dual-cooling coupled state. Detailed Implementation

[0025] Figure 1 This illustration shows a vehicle thermal management system that couples an immersion battery liquid cooling system with an air conditioning system, which is a vehicle thermal management system that couples an immersion battery liquid cooling system with a heat pump air conditioning system.

[0026] The vehicle thermal management system that couples immersion battery liquid cooling with air conditioning includes the vehicle air conditioning system and the immersion battery liquid cooling system.

[0027] The immersion battery liquid cooling system includes a working area 21, a liquid cooling heat exchanger 22, a heater 23 (PTC), an external liquid cooling system heat exchanger 24, a pump 25, and several valves for controlling the flow of the working fluid to achieve operating condition control. The battery pack can be placed in the working area 21. The working fluid in the working area 21 keeps the battery pack submerged. During operation, the working fluid can absorb or release heat from the battery pack, thus controlling the temperature of the battery pack during operation. The pump 25, the external liquid cooling system heat exchanger 24, the heater 23 (PTC), the liquid cooling heat exchanger 22, and the working area 21 are connected sequentially. The external liquid cooling system heat exchanger 24 is connected in parallel to a heat exchanger valve-controlled bypass branch, and the heater 23 (PTC) is connected in parallel to a heater valve-controlled bypass branch.

[0028] The vehicle's air conditioning system includes a compressor 11, a four-way reversing valve 12, and an air conditioning in-vehicle heat exchange device. Figure 1 The in-vehicle air conditioning heat exchange device includes an in-vehicle evaporator 13, an in-vehicle condenser 14, a throttling device 15 (optionally an electronic expansion valve), an external air conditioning heat exchanger 16, a first three-way valve 17, a second three-way valve 18, a third three-way valve 19, and an electric valve 10. The in-vehicle air conditioning heat exchange device, throttling device 15, and external air conditioning heat exchanger 16 are connected sequentially. The in-vehicle air conditioning heat exchange device, external air conditioning heat exchanger 16, and compressor 11 are connected to a four-way reversing valve 12. The in-vehicle air conditioning system includes a coupling branch and a waste heat recovery branch. The coupling branch is connected in parallel with the in-vehicle air conditioning heat exchange device, and the waste heat recovery branch is connected in parallel with the external air conditioning heat exchanger 16. The coupling branch and waste heat recovery branch control the flow of the working fluid of the in-vehicle air conditioning system through the liquid-cooled heat exchanger 22 via the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, and the electric valve 10. The vehicle's air conditioning system and the submerged battery liquid cooling system exchange heat through the liquid-cooled heat exchanger 22 under certain operating conditions. The pipes passing through the air conditioning in-vehicle heat exchange device are defined as the cabin heat exchange branch, and the pipes passing through the air conditioning external heat exchanger are defined as the external heat exchange branch. That is, the coupling branch and the cabin heat exchange branch are connected in parallel, and the waste heat recovery branch and the external heat exchange branch are connected in parallel. In this embodiment, the coupling branch and the waste heat recovery branch share a portion of the piping.

[0029] By controlling the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, and the electric valve 10, the coupling branch, waste heat recovery branch, vehicle compartment heat exchange branch, and external heat exchange branch can be kept in either a flowing or non-flowing state (in this article, a flowing branch means the fluid in the pipeline is in a flowing state, and a non-flowing branch means that the fluid is not in a flowing state due to the control of some valves). This allows the vehicle thermal management system, which couples the submerged battery liquid cooling with the air conditioning, to handle different operating conditions, including low-temperature cold start state, dual heating state, vehicle compartment heating and battery cooling state, dual cooling isolated state, and dual cooling coupled state. The system operation status diagram is shown below. Figure 2-5 As shown.

[0030] In low-temperature cold start mode, the vehicle's air conditioning system does not provide heat to the cabin, but provides heat to the battery pack through the liquid-cooled heat exchanger; in dual heating mode, the vehicle's air conditioning system provides heat to both the cabin and the battery pack through the liquid-cooled heat exchanger; in cabin heating and battery cooling mode, the vehicle's air conditioning system provides heat to the cabin and cooling to the battery pack; in dual cooling isolation mode, the vehicle's air conditioning system provides neither heat nor cooling to the battery pack; in dual cooling coupled mode, the vehicle's air conditioning system provides cooling to both the cabin and the battery pack through the liquid-cooled heat exchanger.

[0031] exist Figure 1 In the system shown, the in-vehicle air conditioning heat exchange device includes an in-vehicle evaporator 13 and an in-vehicle condenser 14. The in-vehicle evaporator 13 is connected in parallel with an evaporator valve-controlled bypass branch, and the in-vehicle condenser 14 is connected in parallel with a condenser valve-controlled bypass branch. In the dual heating state and the vehicle compartment heating battery cooling state, the evaporator valve-controlled bypass branch is open, and the condenser valve-controlled bypass branch is closed. The refrigerant of the in-vehicle air conditioning system bypasses the in-vehicle evaporator through the evaporator valve-controlled bypass branch, and at the same time, the refrigerant of the in-vehicle air conditioning system flows through the in-vehicle condenser. In the dual cooling isolated state and the dual cooling coupled state, the condenser valve-controlled bypass branch is open, and the evaporator valve-controlled bypass branch is closed. The refrigerant of the in-vehicle air conditioning system bypasses the in-vehicle condenser through the condenser valve-controlled bypass branch, and at the same time, the refrigerant of the in-vehicle air conditioning system flows through the in-vehicle evaporator.

[0032] In low-temperature cold start state, dual heating state, and vehicle compartment heating battery cooling state, the heat exchanger valve-controlled bypass branch is opened, and the working liquid in the immersion battery liquid cooling system bypasses the external heat exchanger 24 of the liquid cooling system through the heat exchanger valve-controlled bypass branch.

[0033] In dual heating mode, vehicle compartment heating battery cooling mode, dual cooling isolated mode, and dual cooling coupled mode, the heater valve-controlled bypass branch is opened, and the working liquid in the immersion battery liquid cooling system bypasses the heater 23 (PTC) through the heater valve-controlled bypass branch.

[0034] The liquid-cooled heat exchanger 22 has a first port 221 and a second port 222. A first three-way valve 17 is located between the four-way reversing valve 12 and the air-conditioned vehicle interior heat exchange device, and its other port is connected to the first port 221 of the liquid-cooled heat exchanger 22. A second three-way valve 18 is located between the throttling device 15 and the air-conditioned vehicle exterior heat exchanger 16, and its other port is connected to the second port of the liquid-cooled heat exchanger 22. A third three-way valve 19 is located between the air-conditioned vehicle exterior heat exchanger 16 and the four-way reversing valve 12, and its other port is connected to the first port 221 of the liquid-cooled heat exchanger 22. One port of the electric valve 10 is connected to the wiring between the throttling device 15 and the air-conditioned vehicle interior heat exchange device, and its other end is connected to the second port of the liquid-cooled heat exchanger 22.

[0035] A control method for coupling an in-vehicle thermal management system, controlling, for example... Figure 1 The coupled in-vehicle thermal management system shown includes the following status settings:

[0036] Low temperature cold start state (e.g.) Figure 2 (As shown): Controlling the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, the electric valve 10, and the four-way reversing valve 12 ensures that the coupling branch is in a flowing state, the vehicle compartment heat exchange branch is in a non-flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature, high-pressure refrigerant flowing out of the four-way reversing valve 12 flows sequentially into the liquid-cooled heat exchanger 22, the throttling device 15, and the air conditioning vehicle exterior heat exchanger 16, and then flows back to the compressor 11 through the four-way reversing valve 12; the working liquid in the immersion battery liquid cooling system is pressurized by the pump 25, flows into the heater 23 (PTC) through the heat exchanger valve-controlled bypass branch, then flows into the liquid-cooled heat exchanger 22 and then into the working area to heat the battery pack. Low-temperature cold start mode is beneficial for the rapid heating of the battery pack in low-temperature winter conditions, which has both energy-saving effects and facilitates rapid start-up, reducing the waiting time for vehicle users.

[0037] Dual heating mode (e.g.) Figure 3(As shown): Controlling the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, the electric valve 10, and the four-way reversing valve 12 ensures that the coupling branch is in a flowing state, the vehicle compartment heat exchange branch is in a flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve 12 is diverted by the first three-way valve 17, one part of which flows through the liquid-cooled heat exchanger 22 to heat the working liquid in the submerged battery liquid cooling system, and the other part flows through the air-conditioning vehicle interior heat exchange device to heat the vehicle compartment. After heat exchange, the two refrigerant streams merge and then flow through the throttling device 15, the air-conditioning vehicle exterior heat exchanger 16, and the four-way reversing valve 12 before flowing into the compressor 11; the working liquid in the submerged battery liquid cooling system is pressurized by the pump 25 and flows into the liquid-cooled heat exchanger 22 through the heat exchanger valve-controlled bypass branch and the heater valve-controlled bypass branch before entering the working area 21 to heat the battery pack. When the battery pack temperature is low in winter and heating is required, the dual heating mode allows the heat from the vehicle's air conditioning system to be supplied to the immersion battery liquid cooling system through a liquid cooling heat exchanger, thereby raising the battery temperature. This has a higher energy utilization rate than simple PTC heating.

[0038] Vehicle cabin heating battery cooling status (e.g.) Figure 4 (As shown): Controlling the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, the electric valve 10, and the four-way reversing valve 12, so that the coupling branch is in a non-flowing state, the heat exchange branch in the vehicle compartment is in a flowing state, the heat exchange branch outside the vehicle is in a non-flowing state, and the waste heat recovery branch is in a flowing state; so that the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve 12 flows sequentially into the air-conditioned vehicle interior heat exchange device, the throttling device 15, and the liquid-cooled heat exchanger 22, and then flows into the compressor 11 after passing through the four-way reversing valve 12; the working liquid in the immersion battery liquid cooling system is pressurized by the pump 25 and flows into the liquid-cooled heat exchanger 22 through the heat exchanger valve-controlled bypass branch and the heater valve-controlled bypass branch before entering the working area 21 to heat the battery pack. When the battery pack temperature is too high in winter, it is necessary to dissipate heat from the battery pack on the one hand, and heating is required in the vehicle cabin on the other hand. The working liquid temperature in the immersion battery liquid cooling system is significantly higher than the ambient temperature. Therefore, using the vehicle cabin heating battery cooling state at this time can increase the evaporation temperature of the vehicle's air conditioning system, which is conducive to recovering the heat of the battery pack to heat the vehicle cabin, resulting in a better heating effect. At the same time, the vehicle's air conditioning system also has a better COP.

[0039] Dual-cooling isolated state (e.g.) Figure 5(As shown): Controlling the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, the electric valve 10, and the four-way reversing valve 12, so that the coupling branch is in a non-circulating state, the vehicle compartment heat exchange branch is in a circulating state, the vehicle exterior heat exchange branch is in a circulating state, and the waste heat recovery branch is in a non-circulating state; so that the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve 12 flows sequentially through the air conditioning vehicle exterior heat exchanger 16, the throttling device 15, and the air conditioning vehicle interior heat exchanger, and then flows into the compressor 11 through the four-way reversing valve 12; the working liquid in the immersion battery liquid cooling system is pressurized by the pump 25 and flows into the liquid cooling system vehicle exterior heat exchanger 24, then into the heater valve-controlled bypass branch, then into the liquid cooling heat exchanger 22, and then into the working area 21 to cool the battery pack.

[0040] Dual-cooling coupling state (e.g.) Figure 6 (As shown): Controlling the first three-way valve 17, the second three-way valve 18, the third three-way valve 19, the electric valve 10, and the four-way reversing valve 12 ensures that the coupling branch is in a flowing state, the vehicle compartment heat exchange branch is in a flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve 12 flows sequentially through the air-conditioned vehicle exterior heat exchanger 16 and the throttling device 15, and the refrigerant flowing out of the throttling device 15 is diverted... Part of the liquid flows into the air-conditioned vehicle's heat exchanger, while the other part flows through the liquid-cooled heat exchanger 22. After passing through the first three-way valve 17, the liquid flows into the compressor 11 through the four-way reversing valve 12. The working liquid in the immersion battery liquid cooling system is pressurized by the pump 25 and flows into the liquid cooling system's external heat exchanger 24. The working liquid flowing out of the liquid cooling system's external heat exchanger 24 flows into the liquid cooling heat exchanger 22 through the heater valve-controlled bypass branch. After the working liquid gains cooling, it enters the working area 21 to cool the battery pack.

[0041] As shown in Table 1, compared with independent heat pump systems, the vehicle thermal management system of the present invention, which couples immersion battery liquid cooling with air conditioning, has the following advantages in winter operating conditions:

[0042] 1. Due to the setting of the cabin heating battery cooling state, when the cabin heating battery is in the cooling state, the compressor superheat increases by 25°C because the vehicle air conditioning system recovers the waste heat of the battery, that is, the compressor suction temperature increases to 15°C, the heat pump energy consumption decreases by about 7%, and the heat pump system COP increases by 7%.

[0043] 2. Because the immersion battery liquid cooling system is coupled with the vehicle air conditioning system, the working liquid exchanges heat with the refrigerant of the vehicle air conditioning system. This is different from the original system's outdoor side air cooling, which reduces the fan energy consumption, can better control the battery in a suitable temperature range, and increases the battery's total output energy by about 3%.

[0044] 3. Combining the advantages of both coupling, this invention allows for more energy to be used for electric drive, resulting in a 7% improvement compared to a standalone heat pump system under winter operating conditions.

[0045] Table 1 Figure 4 Comparison of operating conditions

[0046]

[0047]

[0048] As shown in Table 2, compared with independent automotive heat pump systems, the advantages of the immersion battery liquid cooling and air conditioning coupled automotive thermal management system of the present invention in summer operating conditions are as follows:

[0049] 1. In the dual-cooling coupling state, since the immersion battery liquid cooling system is coupled with the vehicle air conditioning system, the working liquid exchanges heat with the refrigerant of the vehicle air conditioning system. This is different from the original system's outdoor side air cooling, which reduces the fan energy consumption and can better control the battery in a suitable temperature range, thereby reducing battery heat generation and increasing the total battery output energy by about 28%.

[0050] 2. Combining the advantages of the two couplings, the system invented in this paper has more energy available for electric drive, which is 33% higher than that of a standalone heat pump system under summer conditions.

[0051] Table 2 Figure 6 Comparison of operating conditions

[0052]

Claims

1. A vehicle thermal management system coupling immersion battery liquid cooling and air conditioning, characterized in that, The system includes an in-vehicle air conditioning system and an immersion battery liquid cooling system. The immersion battery liquid cooling system includes a working area and a liquid cooling heat exchanger. The working area can house the battery pack, and the working liquid within it keeps the battery pack submerged. The working liquid can absorb or release heat from the battery pack. The in-vehicle air conditioning system includes a compressor, a four-way reversing valve, an in-vehicle air conditioning heat exchange device, a throttling device, and an external air conditioning heat exchanger. The in-vehicle air conditioning heat exchange device, the throttling device, and the external air conditioning heat exchanger are connected sequentially. The in-vehicle air conditioning heat exchange device, the external air conditioning heat exchanger, and the compressor are connected to the four-way reversing valve. The in-vehicle air conditioning system includes a coupling branch. The vehicle thermal management system includes a heat recovery branch and a waste heat recovery branch. The coupling branch is connected in parallel with the air conditioning in-vehicle heat exchange device, and the waste heat recovery branch is connected in parallel with the air conditioning external heat exchanger. The vehicle thermal management system coupled with the submerged battery liquid cooling system includes a low-temperature cold start state, a dual heating state, a vehicle cabin heating and battery cooling state, a dual cooling isolated state, and a dual cooling coupled state. In the low-temperature cold start state, the in-vehicle air conditioning system does not provide heat to the vehicle cabin, but provides heat to the battery pack through the liquid cooling heat exchanger. In the dual heating state, the in-vehicle air conditioning system provides heat to the vehicle cabin and also provides heat to the battery pack through the liquid cooling heat exchanger. In the vehicle cabin heating and battery cooling state, the in-vehicle air conditioning system provides heat to the vehicle cabin and cooling to the battery pack. In the dual-cooling isolated state, the vehicle's air conditioning system provides neither heat nor cooling to the battery pack; In the dual-cooling coupling state, the vehicle air conditioning system provides cooling to the vehicle cabin and also provides cooling to the battery pack through the liquid-cooled heat exchanger. In the low-temperature cold start state, dual heating state, vehicle cabin heating and battery cooling state, and dual-cooling coupling state, the refrigerant in the vehicle air conditioning system can flow through the liquid-cooled heat exchanger through the coupling branch or the waste heat recovery branch.

2. The vehicle thermal management system with immersion battery liquid cooling and air conditioning coupling according to claim 1, characterized in that, The air conditioning in-vehicle heat exchange device includes an in-vehicle evaporator and an in-vehicle condenser. The in-vehicle evaporator is connected in parallel with an evaporator valve-controlled bypass branch, and the in-vehicle condenser is connected in parallel with a condenser valve-controlled bypass branch. In the dual heating state and the vehicle cabin heating battery cooling state, the evaporator valve-controlled bypass branch is open, and the condenser valve-controlled bypass branch is closed. The refrigerant of the in-vehicle air conditioning system bypasses the in-vehicle evaporator through the evaporator valve-controlled bypass branch. At the same time, the refrigerant of the in-vehicle air conditioning system flows through the in-vehicle condenser. In the dual-refrigeration isolated state and dual-refrigeration coupled state, the condenser valve-controlled bypass branch is open and the evaporator valve-controlled bypass branch is closed. The refrigerant of the vehicle air conditioning system bypasses the vehicle condenser through the condenser valve-controlled bypass branch. At the same time, the refrigerant of the vehicle air conditioning system flows through the vehicle evaporator.

3. The vehicle thermal management system with submerged battery liquid cooling and air conditioning coupling according to claim 1 or 2, characterized in that, The immersion battery liquid cooling system includes an external heat exchanger for the liquid cooling system and a pump; the pump, the external heat exchanger for the liquid cooling system, the liquid cooling heat exchanger, and the working area are connected in sequence; the external heat exchanger for the liquid cooling system is connected to a valve-controlled bypass branch in parallel. In the low-temperature cold start state, the dual heating state, and the vehicle compartment heating battery cooling state, the valve-controlled bypass branch of the heat exchanger is opened, and the working liquid in the immersion battery liquid cooling system bypasses the external heat exchanger for the liquid cooling system through the valve-controlled bypass branch of the heat exchanger.

4. The vehicle thermal management system with immersion battery liquid cooling and air conditioning coupling according to claim 3, characterized in that, The immersion battery liquid cooling system includes a heater, which is located between the pump and the liquid cooling heat exchanger. The heater is connected in parallel to a heater valve-controlled bypass branch. In the dual heating state, the vehicle compartment heating battery cooling state, the dual cooling isolated state, and the dual cooling coupled state, the heater valve-controlled bypass branch is opened, and the working liquid in the immersion battery liquid cooling system bypasses the heater through the heater valve-controlled bypass branch.

5. The vehicle thermal management system with immersion battery liquid cooling and air conditioning coupling according to claim 4, characterized in that, The vehicle air conditioning system includes a first three-way valve, a second three-way valve, a third three-way valve, and an electric valve. These valves control the refrigerant flow direction and state in the coupling branch or waste heat recovery branch. The liquid-cooled heat exchanger has a first port and a second port. The first three-way valve is located between the four-way reversing valve and the air conditioning vehicle interior heat exchange device, with its other port connected to the first port of the liquid-cooled heat exchanger. The second three-way valve is located between the throttling device and the air conditioning vehicle exterior heat exchanger, with its other port connected to the second port of the liquid-cooled heat exchanger. The third three-way valve is located between the air conditioning vehicle exterior heat exchanger and the four-way reversing valve, with its other port connected to the first port of the liquid-cooled heat exchanger. One port of the electric valve is connected to the wiring between the throttling device and the air conditioning vehicle interior heat exchange device, and the other end is connected to the second port of the liquid-cooled heat exchanger.

6. The vehicle thermal management system with submerged battery liquid cooling and air conditioning coupling according to claim 4 or 5, characterized in that, The working fluid of the immersion battery liquid cooling system is fluorinated liquid, mineral oil, or silicone oil.

7. A control method for a vehicle thermal management system coupling immersion battery liquid cooling and air conditioning, characterized in that, The vehicle thermal management system as described in claim 5 or 6 defines the pipes passing through the in-vehicle heat exchange device of the air conditioning system as the vehicle compartment heat exchange branch, and defines the pipes passing through the external heat exchanger of the air conditioning system as the external heat exchange branch, specifically including the following state settings: Low-temperature cold start state: Control the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve to keep the coupling branch in a flowing state, the vehicle compartment heat exchange branch in a non-flowing state, the vehicle exterior heat exchange branch in a flowing state, and the waste heat recovery branch in a non-flowing state; allow the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve to flow sequentially into the liquid-cooled heat exchanger, the throttling device, and the air-conditioning vehicle exterior heat exchanger, and then flow back to the compressor through the four-way reversing valve; the working liquid in the immersion battery liquid cooling system is pressurized by the pump, flows into the heater through the valve-controlled bypass branch of the heat exchanger, then flows into the liquid-cooled heat exchanger, and then enters the working area to heat the battery pack; Dual heating mode: Controlling the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve ensures that the coupling branch is in a flowing state, the vehicle compartment heat exchange branch is in a flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve is diverted by the first three-way valve, with one part flowing through the liquid-cooled heat exchanger to heat the working liquid in the submerged battery liquid cooling system, and the other part flowing through the air-conditioning vehicle interior heat exchange device to heat the vehicle compartment. After heat exchange, the two refrigerant streams merge and then flow through the throttling device, the air-conditioning vehicle exterior heat exchanger, and the four-way reversing valve before flowing into the compressor; the working liquid in the submerged battery liquid cooling system is pressurized by the pump and flows into the liquid-cooled heat exchanger through the heat exchanger valve-controlled bypass branch and the heater valve-controlled bypass branch before entering the working area to heat the battery pack; Cooling status of the vehicle compartment heating battery: Controlling the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve to keep the coupling branch in a non-flowing state, the vehicle compartment heat exchange branch in a flowing state, the vehicle exterior heat exchange branch in a non-flowing state, and the waste heat recovery branch in a flowing state; allowing the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve to sequentially flow into the air-conditioning vehicle interior heat exchange device, the throttling device, and the liquid-cooled heat exchanger, and then flow into the compressor after passing through the four-way reversing valve; the working liquid in the immersion battery liquid cooling system, after being pressurized by the pump, flows into the liquid-cooled heat exchanger through the heat exchanger valve-controlled bypass branch and the heater valve-controlled bypass branch before entering the working area to heat the battery pack; Dual refrigeration isolated state: Controlling the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve, so that the coupling branch is in a non-flowing state, the vehicle compartment heat exchange branch is in a flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve flows sequentially through the air conditioning vehicle exterior heat exchanger, the throttling device, and the air conditioning vehicle interior heat exchanger, and then flows into the compressor through the four-way reversing valve; the working liquid in the immersion battery liquid cooling system is pressurized by the pump and flows into the liquid cooling system vehicle exterior heat exchanger, then into the heater valve-controlled bypass branch, then into the liquid cooling heat exchanger, and then into the working area to cool the battery pack; Dual refrigeration coupling state: Controlling the first three-way valve, the second three-way valve, the third three-way valve, the electric valve, and the four-way reversing valve ensures that the coupling branch is in a flowing state, the vehicle compartment heat exchange branch is in a flowing state, the vehicle exterior heat exchange branch is in a flowing state, and the waste heat recovery branch is in a non-flowing state; the high-temperature and high-pressure refrigerant flowing out of the four-way reversing valve flows sequentially through the air conditioning vehicle exterior heat exchanger and the throttling device. The refrigerant flowing out of the throttling device is split, with one part flowing into the air conditioning vehicle interior heat exchanger and the other part flowing through the liquid-cooled heat exchanger. After being combined through the first three-way valve, it flows into the compressor through the four-way reversing valve; the working liquid in the immersion battery liquid cooling system is pressurized by the pump and flows into the liquid cooling system vehicle exterior heat exchanger. The working liquid flowing out of the liquid cooling system vehicle exterior heat exchanger flows into the liquid cooling heat exchanger through the heater valve-controlled bypass branch. After the working liquid gains cooling, it enters the working area to cool the battery pack.

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