Thermal management system of electric automobile

Abstract

The invention relates to the technical field of heat management, and provides an electric vehicle heat management system which comprises a heat pump air conditioning system, a battery heat management system and a battery end heat exchanger. The battery heat management system at least comprises a liquid storage tank, a booster pump and a battery heat exchange assembly, and the battery heat management system is filled with a carbon dioxide medium in a subcritical state; the battery end heat exchanger comprises a first heat exchange channel and a second heat exchange channel, the first heat exchange channel is connected with the heat pump air conditioning system, the second heat exchange channel is connected with the battery heat management system, and the second heat exchange channel is located between the battery heat exchange assembly and the liquid storage tank. Through the arrangement, the carbon dioxide medium of the battery heat management system not only performs temperature difference heat exchange, but also performs phase change heat exchange in the battery end heat exchanger and the battery heat exchange assembly, so that the heat exchange efficiency is improved. The temperature of the carbon dioxide medium does not change during phase-change heat exchange, and the temperature of the carbon dioxide medium flowing to each position of the battery heat exchange assembly is consistent, so that the temperature distribution uniformity in the battery pack is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management, and in particular to a thermal management system for an electric vehicle. Background Art

[0002] Thermal management technology plays a key role in the safety and comfort of electric vehicles. For electric vehicles, it is necessary not only to adjust the temperature of the passenger compartment, but also to manage the temperature of the battery pack, etc., and to control the temperature of the passenger compartment and the battery pack within a reasonable range. Therefore, the thermal management system of electric vehicles includes a heat pump air conditioning system and a battery thermal management system, and the battery thermal management system is generally coupled with the heat pump air conditioning system. The medium in the heat pump air conditioning system is a refrigerant, while the medium in the battery thermal management system is a coolant such as water. The heat pump air conditioning system is used to heat or cool the coolant in the battery thermal management system, thereby providing heat or cold to the battery pack.

[0003] The coolant is only a simple heat exchange medium in the battery thermal management system. During the circulation in the battery thermal management system, it always remains in the same phase and does not undergo phase change. The heat exchange is only based on the temperature difference between the coolant and the refrigerant in the heat pump air conditioning system and the temperature difference between the coolant and the battery pack. The heat exchange efficiency is limited to the thermal capacity of the system, the cooling and heating time of the battery pack is long, and the thermal management efficiency of the battery pack is low. Moreover, as the coolant circulates in the battery pack, the temperature of the coolant will change, resulting in different temperatures of the coolant at different positions in the battery pack. Correspondingly, the temperatures of the battery modules at different positions in the battery pack are also different, resulting in uneven temperature distribution inside the battery pack.

[0004] Therefore, how to solve the problem of low thermal management efficiency of battery packs and uneven temperature distribution in battery packs in electric vehicle thermal management systems in related technologies has become an important technical problem to be solved by those skilled in the art. Summary of the invention

[0005] The present invention provides an electric vehicle thermal management system, which is used to solve the defects of the electric vehicle thermal management system in the related art, that is, the thermal management efficiency of the battery pack is low and the temperature distribution in the battery pack is uneven.

[0006] The present invention provides an electric vehicle thermal management system, comprising: Heat pump air conditioning system; A battery thermal management system, comprising at least a liquid storage tank, a booster pump and a battery heat exchange component connected to form a loop, wherein the battery heat exchange component is suitable for heat exchange with the battery pack, and the battery thermal management system is filled with a subcritical carbon dioxide medium; The battery-end heat exchanger includes a first heat exchange channel and a second heat exchange channel capable of performing heat exchange, wherein the first heat exchange channel is connected to the heat pump air conditioning system, the second heat exchange channel is connected to the battery thermal management system, and the second heat exchange channel is located between the battery heat exchange assembly and the liquid storage tank.

[0007] According to an electric vehicle thermal management system provided by the present invention, the battery pack comprises: A first housing having an accommodation space therein for accommodating a battery module; A first filling mechanism is arranged inside the first shell, and the first filling mechanism is suitable for filling the carbon dioxide medium into the first shell. The first filling mechanism is connected to the outlet end of the booster pump through a first filling pipeline. A first control valve is arranged on the first filling pipeline, and the first control valve is suitable for controlling the on-off state of the first filling pipeline.

[0008] According to an electric vehicle thermal management system provided by the present invention, the first charging mechanism comprises: The filling main pipe is provided with a plurality of filling ports, the plurality of filling ports are distributed at intervals on the filling main pipe, and the middle position of the filling main pipe is connected to the first filling pipeline.

[0009] According to a thermal management system for an electric vehicle provided by the present invention, the battery module comprises a plurality of battery cells, the battery cells have temperature-sensing nozzles and temperature-sensing elements, the temperature-sensing nozzles are adapted to switch to an open state when the temperature of the battery cells is greater than a first preset temperature value, so as to allow the high-temperature medium in the battery cells to be ejected; The temperature sensing element is electrically connected to the first control valve, and the first control valve is adapted to switch to an open state when the temperature of the battery cell is greater than a second preset temperature value, so as to allow the carbon dioxide medium in the battery thermal management system to enter the interior of the first housing.

[0010] According to an electric vehicle thermal management system provided by the present invention, a first pressure relief valve is provided on the first housing, and the first pressure relief valve is adapted to switch to an open state when the pressure in the first housing reaches a first preset pressure value, so as to release the pressure of the first housing; There are multiple first pressure relief valves, and the multiple first pressure relief valves are arranged at one end of the first shell close to the temperature sensing nozzle, and the multiple first pressure relief valves are distributed at intervals on the first shell.

[0011] According to an electric vehicle thermal management system provided by the present invention, the heat pump air conditioning system comprises: A heat pump circuit includes a compressor, a four-way valve, a first external radiator, a first expansion valve, a second expansion valve, an internal heat exchanger and a gas-liquid separator, wherein the refrigerant filled in the heat pump circuit is flammable; A second shell has a containing space inside, and at least the compressor, the four-way valve, the first expansion valve, the second expansion valve, the in-vehicle heat exchanger and the gas-liquid separator are arranged inside the second shell; A second filling mechanism is arranged inside the second shell, and the second filling mechanism is suitable for filling the carbon dioxide medium into the inside of the second shell. The second filling mechanism is connected to the outlet end of the booster pump through a second filling pipeline. A second control valve is arranged on the second filling pipeline, and the second control valve is suitable for controlling the on-off state of the second filling pipeline.

[0012] According to an electric vehicle thermal management system provided by the present invention, the heat pump air conditioning system further includes: a temperature detection element, disposed inside the second housing, the temperature detection element being adapted to detect the temperature inside the second housing, the temperature detection element being electrically connected to the second control valve, the second control valve being adapted to switch to an open state when the temperature inside the second housing is greater than a third preset temperature value, so as to allow the carbon dioxide medium in the battery thermal management system to enter the interior of the second housing; A second pressure relief valve is arranged in the second shell. The second pressure relief valve is suitable for switching to an open state when the pressure in the second shell reaches a second preset pressure value to release the pressure of the second shell. The second pressure relief valve and the second filling mechanism are distributed at opposite ends of the second shell.

[0013] According to an electric vehicle thermal management system provided by the present invention, the first external radiator is arranged outside the second housing, and the heat pump air conditioning system further includes: A third filling mechanism is arranged around the first external radiator, and is suitable for filling carbon dioxide medium into the first external radiator. The third filling mechanism is connected to the outlet end of the boost pump through a third filling pipeline. A third control valve is arranged on the third filling pipeline, and the third control valve is suitable for controlling the on-off state of the third filling pipeline.

[0014] According to an electric vehicle thermal management system provided by the present invention, the heat pump air conditioning system further includes: An outdoor heat exchanger is arranged inside the second shell, and includes a third heat exchange channel and a fourth heat exchange channel capable of performing heat exchange, one end of the third heat exchange channel is connected to the four-way valve, and the other end of the third heat exchange channel is connected to the first expansion valve and the second expansion valve, and the fourth heat exchange channel is connected to the first outdoor radiator to form an outdoor heat exchange circuit, and the outdoor heat exchanger is suitable for heat exchange between the heat exchange medium in the outdoor heat exchange circuit and the refrigerant in the heat pump circuit, and the outdoor heat exchange circuit is suitable for heat exchange with the air outside the vehicle.

[0015] According to an electric vehicle thermal management system provided by the present invention, the battery heat exchange component is configured as a cover plate of the first housing; Alternatively, the battery heat exchange assembly is disposed inside the first housing, and the battery heat exchange assembly includes: At least two first heat exchange plates are provided, each of which is spaced apart in the transverse direction of the first shell, each of which extends in the longitudinal direction of the first shell, and a battery cell of the battery module is suitable for being placed between two adjacent first heat exchange plates; A pair of second heat exchange plates, each of the first heat exchange plates is located between a pair of the second heat exchange plates, and each of the first heat exchange plates is connected to the second heat exchange plate, and a pair of the second heat exchange plates are respectively connected to the outlet end of the booster pump and the second heat exchange channel.

[0016] The electric vehicle thermal management system provided by the present invention includes a heat pump air conditioning system, a battery thermal management system and a battery end heat exchanger. The battery thermal management system includes at least a liquid storage tank, a booster pump and a battery heat exchange component, and the liquid storage tank, the booster pump and the battery heat exchange component are connected to form a loop. The battery thermal management system is filled with a subcritical carbon dioxide medium. When the booster pump is running, the pressure of the carbon dioxide can be increased and the carbon dioxide medium can circulate in the loop. The battery end heat exchanger includes a first heat exchange channel and a second heat exchange channel capable of heat exchange. The first heat exchange channel is connected to the heat pump air conditioning system, and the second heat exchange channel is connected to the battery thermal management system. The second heat exchange channel is located between the battery heat exchange component and the liquid storage tank. The heat pump air conditioning system can be used to cool or heat the carbon dioxide medium in the battery thermal management system to reduce or increase the temperature of the carbon dioxide medium. The battery heat exchange component is used to perform heat exchange with the battery pack, and then cool or heat the battery pack, thereby adjusting the temperature of the battery pack. Carbon dioxide has a high heat capacity and can achieve efficient cooling at a low flow rate. The subcritical carbon dioxide medium of the battery thermal management system not only performs temperature difference heat exchange in the battery end heat exchanger and the battery heat exchange assembly, but also performs phase change heat exchange, which improves the heat exchange efficiency. The temperature of the carbon dioxide medium does not change during phase change heat exchange, and the temperature of the carbon dioxide medium flowing to each position of the battery heat exchange assembly is consistent, which improves the uniformity of temperature distribution in the battery pack and solves the problem of low thermal management efficiency of the battery pack and uneven temperature distribution in the battery pack in the electric vehicle thermal management system in the related art. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of the electric vehicle thermal management system with an off-vehicle heat exchanger provided by the present invention when cooling the passenger compartment and battery pack in the vehicle.

[0019] Figure 2 It is a structural schematic diagram of the electric vehicle thermal management system with an off-vehicle heat exchanger provided by the present invention when heating the passenger compartment and battery pack in the vehicle.

[0020] Figure 3 It is a structural schematic diagram of the electric vehicle thermal management system provided by the present invention without an external heat exchanger when cooling the passenger compartment and battery pack in the vehicle.

[0021] Figure 4It is a schematic structural diagram of the battery pack provided by the present invention when the battery heat exchange component is configured as a cover plate.

[0022] Figure 5 It is a schematic structural diagram of the battery pack provided by the present invention when the battery heat exchange assembly includes a first heat exchange plate and a second heat exchange plate.

[0023] Figure 6 It is a two-phase cycle pressure-enthalpy diagram of a carbon dioxide medium when the electric vehicle thermal management system provided by the present invention cools down a battery pack.

[0024] Figure 7 It is a two-phase cycle pressure-enthalpy diagram of the carbon dioxide medium when the electric vehicle thermal management system provided by the present invention heats the battery pack.

[0025] Reference numerals: 1. Liquid storage tank; 2. Booster pump; 3. Battery heat exchange assembly; 4. Battery end heat exchanger; 5. First shell; 6. First filling mechanism; 7. First filling pipeline; 8. First control valve; 9. Filling main pipe; 10. Filling port; 11. Battery cell; 12. Temperature sensing nozzle; 13. First pressure relief valve; 14. Compressor; 15. Four-way valve; 16. First external radiator; 17. First expansion valve; 18. Second expansion valve; 19. In-car heat exchanger; 20. Gas-liquid separator; 21. Second shell; 22. Second filling mechanism; 23. The second filling pipeline; 24. The second control valve; 25. The temperature detection element; 26. The second pressure relief valve; 27. The third filling mechanism; 28. The third filling pipeline; 29. ​​The third control valve; 30. The external heat exchanger; 31. The cover plate; 32. The first heat exchange plate; 33. The second heat exchange plate; 34. The first water tank; 35. The first power pump; 36. The internal heat exchange core; 37. The first three-way valve; 38. The second three-way valve; 39. The third three-way valve; 40. The second external radiator; 41. The shell; 42. The second water tank; 43. The second power pump. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Combine the following Figures 1 to 7 The electric vehicle thermal management system of the present invention is described.

[0028] like Figures 1 to 7As shown, the electric vehicle thermal management system provided by the embodiment of the present invention includes a heat pump air conditioning system, a battery thermal management system and a battery end heat exchanger 4.

[0029] Specifically, the battery thermal management system at least includes a liquid storage tank 1, a booster pump 2 and a battery heat exchange component 3, which are connected to form a loop. The battery thermal management system is filled with a subcritical carbon dioxide medium, and when the booster pump 2 is running, the pressure of the carbon dioxide can be increased and the carbon dioxide medium can circulate in the loop.

[0030] The battery end heat exchanger 4 includes a first heat exchange channel and a second heat exchange channel capable of heat exchange. The first heat exchange channel is connected to the heat pump air conditioning system, and the second heat exchange channel is connected to the battery thermal management system. The second heat exchange channel is located between the battery heat exchange assembly 3 and the liquid storage tank 1.

[0031] The heat pump air conditioning system can be used to cool or heat the carbon dioxide medium in the battery thermal management system to reduce or increase the temperature of the carbon dioxide medium. The battery heat exchange component 3 is used to perform heat exchange with the battery pack to cool or heat the battery pack, thereby adjusting the temperature of the battery pack.

[0032] With this arrangement, carbon dioxide has a higher heat capacity and can achieve efficient cooling at a lower flow rate. The subcritical carbon dioxide medium of the battery thermal management system not only performs temperature difference heat exchange in the battery end heat exchanger 4 and the battery heat exchange component 3, but also performs phase change heat exchange, thereby improving the heat exchange efficiency. The temperature of the carbon dioxide medium does not change during phase change heat exchange, and the temperature of the carbon dioxide medium flowing to each position of the battery heat exchange component 3 is consistent, which improves the uniformity of temperature distribution in the battery pack and solves the problem of low thermal management efficiency of the battery pack and uneven temperature distribution in the battery pack in the electric vehicle thermal management system in the related art.

[0033] The liquid storage tank 1 is provided with a liquid level sensor for detecting the liquid level change in the liquid storage tank 1 and for feedback control to ensure that the pure liquid carbon dioxide medium enters the booster pump 2. The liquid storage tank 1 is also provided with a gas pressure sensor for detecting the pressure of the gaseous carbon dioxide medium in the liquid storage tank 1.

[0034] In the embodiment of the present invention, the battery pack includes a first housing 5 and a first filling mechanism 6 .

[0035] The first housing 5 has an accommodating space inside for accommodating the battery module and the first filling mechanism 6 .

[0036] The first filling mechanism 6 is arranged inside the first housing 5 and connected to the outlet of the booster pump 2 through the first filling pipeline 7. The first filling pipeline 7 is provided with a first control valve 8 for controlling the on-off state of the first filling pipeline 7.

[0037] When the first control valve 8 is in an open state, the boost pump 2 is running, and the carbon dioxide medium in the liquid storage tank 1 can be filled into the interior of the first housing 5. When the first control valve 8 is in a closed state, the carbon dioxide medium in the liquid storage tank 1 of the battery thermal management system cannot enter the interior of the first housing 5.

[0038] The carbon dioxide medium is non-flammable and highly insulating, and can be used as a fire extinguishing agent for extinguishing fires. When the temperature inside the battery pack is too high or thermal runaway problems such as combustion warnings occur, the first control valve 8 can be switched to an open state, and the carbon dioxide medium in the battery thermal management system can be quickly injected into the first shell 5 to quickly cool the inside of the battery pack, while isolating the air to extinguish the fire and ensure the safety of the battery pack.

[0039] This arrangement couples the battery thermal management system with the thermal runaway protection system of the battery pack, reduces system redundancy, and simplifies the structure of the thermal management system of the electric vehicle.

[0040] In this embodiment, the first filling mechanism 6 includes a filling main pipe 9, and the filling main pipe 9 is provided with a plurality of filling ports 10, and the plurality of filling ports 10 are spaced apart on the filling main pipe 9. The middle position of the filling main pipe 9 is connected to the first filling pipeline 7, and the carbon dioxide medium in the first filling pipeline 7 enters the filling main pipe 9 from the middle of the filling main pipe 9 and flows to both ends of the filling main pipe 9. The carbon dioxide medium can quickly flow to each filling port 10 of the filling main pipe 9, which is conducive to improving the filling efficiency of the carbon dioxide medium into the first housing 5.

[0041] The filling main pipe 9 can be extended in the longitudinal direction of the first housing 5, and at least two rows of filling ports 10 are arranged on the side wall of the filling main pipe 9, and the filling ports 10 in each row are distributed at intervals along the circumference of the filling main pipe 9, and the filling ports 10 in each row are distributed at intervals along the axial direction of the filling main pipe 9. This allows the carbon dioxide medium to be filled in different directions in the first housing 5, so that each position in the first housing 5 can be quickly filled with the carbon dioxide medium.

[0042] In this embodiment, the battery module includes a plurality of battery cells 11, and the plurality of battery cells 11 are disposed in the first housing 5. Each battery cell 11 has a temperature sensing nozzle 12 and a temperature sensing element, and the temperature sensing nozzle 12 is used to switch to an open state when the temperature of the battery cell 11 is greater than a first preset temperature value, so as to allow the electrolyte and other high-temperature media in the battery cell 11 to be ejected.

[0043] The temperature sensing element is electrically connected to the first control valve 8 and can sense the temperature of the battery cell 11 . The first control valve 8 is used to switch to an open state when the temperature of the battery cell 11 is greater than a second preset temperature value to allow the carbon dioxide medium in the battery thermal management system to enter the interior of the first shell 5 .

[0044] The first preset temperature value and the second preset temperature value can be determined according to actual needs. The first preset temperature value can be equal to the second preset temperature value, or the first preset temperature value can be unequal to the second preset temperature value.

[0045] In this embodiment, a first pressure relief valve 13 is provided on the first shell 5. The first pressure relief valve 13 is used to switch to an open state when the pressure in the first shell 5 reaches a first preset pressure value, so as to release the pressure of the first shell 5 and avoid explosion and other problems caused by excessive pressure in the battery pack.

[0046] There are multiple first pressure relief valves 13, which are arranged at one end of the first housing 5 close to the temperature-sensing nozzle 12, and the multiple first pressure relief valves 13 are distributed at intervals on the first housing 5. In other words, the multiple first pressure relief valves 13 and the temperature-sensing nozzle 12 correspond to the same end of the first housing 5, which can facilitate the high-temperature medium sprayed from the battery cell 11 to be smoothly discharged to the outside of the first housing 5.

[0047] In the embodiment of the present invention, the heat pump air conditioning system includes a heat pump circuit, a second housing 21 and a second filling mechanism 22 .

[0048] The heat pump circuit includes a compressor 14, a four-way valve 15, a first external radiator 16, a first expansion valve 17, a second expansion valve 18, an internal heat exchanger 19 and a gas-liquid separator 20. The refrigerant filled in the heat pump circuit is flammable, and the refrigerant can be but is not limited to propane (refrigerant code R290), carbon dioxide (refrigerant code R744), tetrafluoroethane (refrigerant code R134a) or tetrafluoropropylene (refrigerant code R1234yf), which have the advantages of high energy efficiency, environmental friendliness and low cost.

[0049] The heat pump air conditioning system also includes an in-vehicle heat exchange circuit, in which the in-vehicle heat exchanger 19 is used to exchange heat between the heat exchange medium in the in-vehicle heat exchange circuit and the refrigerant in the heat pump circuit. The in-vehicle heat exchange circuit is used to exchange heat between the heat exchange medium in the in-vehicle heat exchange circuit and the air in the passenger compartment to adjust the temperature of the passenger compartment.

[0050] The in-vehicle heat exchanger 19 includes a fifth heat exchange channel and a sixth heat exchange channel capable of heat exchange. The fifth heat exchange channel is connected in series with the first expansion valve 17 as a first branch. The second expansion valve 18 is connected in series with the first heat exchange channel of the battery-end heat exchanger 4 as a second branch. The first branch is connected in parallel with the second branch. By controlling the opening of the first expansion valve 17 and the second expansion valve 18 respectively, the flow of the refrigerant in the first branch and the second branch can be distributed.

[0051] The heat exchange circuit in the vehicle is a secondary circuit, and the heat exchange medium inside it can be different from the refrigerant in the heat pump circuit. The heat exchange medium in the heat exchange circuit in the vehicle can be, but is not limited to, ethylene glycol solution, which is non-flammable and can prevent the leakage of flammable refrigerant into the passenger compartment of the vehicle, and is safer to use.

[0052] The in-vehicle heat exchange circuit includes a first water tank 34, a first power pump 35 and an in-vehicle heat exchange core 36. The first water tank 34, the first power pump 35, the in-vehicle heat exchange core 36 and the sixth heat exchange channel of the in-vehicle heat exchanger 19 are sequentially connected to form a circuit. The heat exchange medium can exchange heat with the air in the passenger compartment at the position of the in-vehicle heat exchange core 36 to provide cooling or heating for the passenger compartment.

[0053] When the compressor 14 is running, it can provide cold or heat to the sixth heat exchange channel of the in-vehicle heat exchanger 19 and the second heat exchange channel of the battery-end heat exchanger 4, thereby transferring the cold or heat to the passenger compartment and battery pack in the vehicle.

[0054] By switching the state of the four-way valve 15, the cooling mode and the heating mode of the passenger compartment and the battery pack in the vehicle can be switched.

[0055] The second housing 21 has a storage space inside, and at least the compressor 14, the four-way valve 15, the first expansion valve 17, the second expansion valve 18, the in-vehicle heat exchanger 19 and the gas-liquid separator 20 are arranged inside the second housing 21. There is a risk of leakage of the refrigerant filled in the heat pump circuit. Even if the heat pump circuit has a problem of flammable refrigerant leakage, the leaked refrigerant gathers inside the second housing 21, and will not pollute or harm the outside of the second housing 21.

[0056] The second filling mechanism 22 is arranged inside the second housing 21 and connected to the outlet of the booster pump 2 through the second filling pipeline 23. The second filling pipeline 23 is provided with a second control valve 24 for controlling the on-off state of the second filling pipeline 23.

[0057] When the second control valve 24 is in an open state, the boost pump 2 is running, and the carbon dioxide medium in the liquid storage tank 1 can be filled into the interior of the second housing 21. When the second control valve 24 is in a closed state, the carbon dioxide medium in the liquid storage tank 1 of the battery thermal management system cannot enter the interior of the second housing 21.

[0058] When the temperature inside the second shell 21 is high or a combustion warning problem occurs inside the second shell 21, the second control valve 24 can be switched to an open state, and the carbon dioxide medium in the battery thermal management system can be quickly injected into the second shell 21 to quickly cool the second shell 21 and the components inside it, while isolating the air to extinguish the fire, thereby ensuring the safety of the heat pump air conditioning system.

[0059] The second filling pipeline 23 extends into the interior of the second housing 21, and the end opening of the second filling pipeline 23 can be used as the second filling mechanism 22. The second filling mechanism 22 can also be set as a nozzle, and the nozzle is set at the end of the second filling pipeline 23 to enhance the spray cooling effect.

[0060] In this embodiment, the heat pump air conditioning system further includes a temperature detection element 25 and a second pressure relief valve 26 .

[0061] The temperature detection element 25 is disposed inside the second housing 21, and is used to detect the temperature inside the second housing 21. The temperature detection element 25 is electrically connected to the second control valve 24, and the second control valve 24 is used to switch to an open state when the temperature inside the second housing 21 is greater than a third preset temperature value, so as to allow the carbon dioxide medium in the battery thermal management system to enter the interior of the second housing 21.

[0062] The second pressure relief valve 26 is disposed in the second shell 21 . The second pressure relief valve 26 is used to switch to an open state when the pressure in the second shell 21 reaches a second preset pressure value, so as to release the pressure of the second shell 21 and avoid explosion and other problems caused by excessive pressure in the second shell 21 .

[0063] The second pressure relief valve 26 and the second filling mechanism 22 are distributed at two opposite ends of the second shell 21. The second filling mechanism 22 fills the carbon dioxide medium at one end of the second shell 21, and the medium in the second shell 21 is discharged from the opposite end of the second shell 21. The pressure relief of the second pressure relief valve 26 will not reduce the flow path of the carbon dioxide medium in the second shell 21, and can ensure the sufficient circulation of the carbon dioxide medium in the second shell 21, so as to fully cool down and extinguish the interior of the second shell 21.

[0064] In some embodiments, the first external radiator 16 is directly connected to the four-way valve 15, the first branch and the second branch. Specifically, the first external radiator 16 has a seventh heat exchange channel and an eighth heat exchange channel capable of heat exchange, and the eighth heat exchange channel is connected to the outside atmosphere. The first interface of the four-way valve 15 is connected to the exhaust end of the compressor 14, and the second interface of the four-way valve 15, one end of the first branch and one end of the second branch are connected to the seventh heat exchange channel of the first external radiator 16. The other end of the first branch and the other end of the second branch are connected to the third interface of the four-way valve 15, and the fourth interface of the four-way valve 15 is connected to the gas-liquid separator 20, which is connected to the air intake end of the compressor 14. When the first interface of the four-way valve 15 is connected to the second interface and the third interface is connected to the fourth interface, the heat pump circuit can cool the passenger compartment and the battery in the vehicle. When the first interface of the four-way valve 15 is connected to the third interface and the second interface is connected to the fourth interface, the heat pump circuit can heat the passenger compartment and the battery in the vehicle.

[0065] That is to say, the medium flowing in the first external radiator 16 is also a flammable refrigerant. The first external radiator 16 needs to fully exchange heat with the outside to ensure the cooling efficiency and heating efficiency of the heat pump circuit. Therefore, the first external radiator 16 needs to be arranged outside the second housing 21.

[0066] At this time, the heat pump air conditioning system further includes a third charging mechanism 27, which is arranged around the first external radiator 16. The third charging mechanism 27 is connected to the outlet end of the boost pump 2 through a third charging pipeline 28, and a third control valve 29 is arranged on the third charging pipeline 28, and the third control valve 29 is used to control the on-off state of the third charging pipeline 28.

[0067] When the third control valve 29 is in an open state, the boost pump 2 is running, and the carbon dioxide medium in the liquid storage tank 1 can be filled around the first external radiator 16. When the third control valve 29 is in a closed state, the carbon dioxide medium in the liquid storage tank 1 of the battery thermal management system cannot flow around the first external radiator 16.

[0068] There is also a risk of flammable refrigerant leakage at the location of the first external radiator 16. When the temperature around the first external radiator 16 is too high or a combustion warning occurs, the third control valve 29 can be switched to an open state, and the carbon dioxide medium in the battery thermal management system can be used to cool the first external radiator 16 and extinguish the fire to ensure safety.

[0069] In some other embodiments, the heat pump air conditioning system further includes an outdoor heat exchanger 30, which is disposed inside the second housing 21. The outdoor heat exchanger 30 includes a third heat exchange channel and a fourth heat exchange channel capable of heat exchange, one end of the third heat exchange channel is connected to the four-way valve 15, the other end of the third heat exchange channel is connected to the first expansion valve 17 and the second expansion valve 18, and the fourth heat exchange channel is connected to the first outdoor radiator 16 to form an outdoor heat exchange circuit.

[0070] The exterior heat exchanger 30 can perform heat exchange between the heat exchange medium in the exterior heat exchange circuit and the refrigerant in the heat pump circuit, and the exterior heat exchange circuit can perform heat exchange with the air outside the vehicle.

[0071] That is to say, the third heat exchange channel of the external heat exchanger 30 is connected to the four-way valve 15, the first branch and the second branch, and the medium flowing through the third heat exchange channel of the external heat exchanger 30 is a flammable refrigerant. The first external radiator 16 is no longer directly connected to the four-way valve 15, the first branch and the second branch, and the first external radiator 16 is connected to the fourth heat exchange channel to form an external heat exchange circuit. The external heat exchange circuit serves as a secondary circuit, and the heat exchange medium inside it can be different from the composition of the refrigerant in the heat pump circuit. The heat exchange medium in the external heat exchange circuit can be, but is not limited to, an ethylene glycol solution, which is non-flammable, can avoid leakage of flammable refrigerants to the outside of the vehicle, and has high safety in use.

[0072] The off-vehicle heat exchanger 30 can be disposed inside the second housing 21, and centrally protected together with the compressor 14, the four-way valve 15, the first expansion valve 17, the second expansion valve 18, the on-vehicle heat exchanger 19 and the gas-liquid separator 20. The first off-vehicle radiator 16 will no longer have the problem of leakage of flammable refrigerant, and in this case, the third charging mechanism 27 can be cancelled.

[0073] The off-vehicle heat exchange circuit further includes a second water tank 42 and a second power pump 43. The first off-vehicle radiator 16, the second water tank 42, the second power pump 43 and the fourth heat exchange channel of the off-vehicle heat exchanger 30 are sequentially connected to form a circuit.

[0074] Regarding the structure of the battery heat exchange assembly 3, in some embodiments, the battery heat exchange assembly 3 can be configured as the cover plate 31 of the first housing 5. That is to say, the battery heat exchange assembly 3 is set as a flat plate structure, the first housing 5 includes a shell 41 with an open upper end, and the battery heat exchange assembly 3 is connected to the open end of the shell 41, so that the battery heat exchange assembly 3 serves as the cover plate 31 that covers the open upper end of the shell 41.

[0075] At this time, the flat plate structure has a tortuous flow channel inside to increase the flow path and flow time of the carbon dioxide medium in the flat plate structure, making the heat exchange more efficient, sufficient and uniform. A medium interface for the carbon dioxide medium to enter and exit the cavity is provided on the flat plate structure.

[0076] In some other embodiments, the battery heat exchange assembly 3 is disposed inside the first housing 5 , and the battery heat exchange assembly 3 includes a first heat exchange plate 32 and a second heat exchange plate 33 .

[0077] At least two first heat exchange plates 32 are provided, and the first heat exchange plates 32 are spaced apart in the transverse direction of the first housing 5, and each first heat exchange plate 32 extends in the longitudinal direction of the first housing 5. The battery cells 11 of the battery module are placed between two adjacent first heat exchange plates 32, and the battery cells 11 of the battery module are in contact with the first heat exchange plates 32, and heat exchange can be performed to achieve temperature regulation of the battery cells 11.

[0078] A pair of second heat exchange plates 33 are provided, each first heat exchange plate 32 is located between a pair of second heat exchange plates 33, and each first heat exchange plate 32 is connected to the second heat exchange plate 33, and a pair of second heat exchange plates 33 are respectively connected to the outlet end of the boost pump 2 and the second heat exchange channel of the battery-end heat exchanger 4.

[0079] A medium interface is respectively provided on a pair of second heat exchange plates 33 , wherein the carbon dioxide medium in one second heat exchange plate 33 can flow into each first heat exchange plate 32 , and the carbon dioxide medium in each first heat exchange plate 32 can flow into another second heat exchange plate 33 .

[0080] A tortuous flow channel is provided inside the first heat exchange plate 32 and the second heat exchange plate 33 to increase the flow path and flow time of the carbon dioxide medium in the first heat exchange plate 32 and the second heat exchange plate 33, so as to make the heat exchange more efficient, sufficient and uniform.

[0081] The battery heat exchange assembly 3 is configured as a structure in which a first heat exchange plate 32 and a second heat exchange plate 33 are combined, so that the battery heat exchange assembly 3 surrounds the battery cell 11, which can also reduce the risk of thermal runaway spreading to a certain extent.

[0082] Regarding the structure of the battery thermal management system, in this embodiment, the battery thermal management system further includes a first three-way valve 37 , a second three-way valve 38 , a third three-way valve 39 and a second external radiator 40 .

[0083] The first interface of the first three-way valve 37 is connected to the outlet end of the boost pump 2, the second interface of the first three-way valve 37 is connected to the battery heat exchange assembly 3 through the second pipeline, and the third interface of the first three-way valve 37 is connected to one end of the second heat exchange channel of the battery-end heat exchanger 4 through the third pipeline.

[0084] The first interface of the second three-way valve 38 is connected to the battery heat exchange assembly 3, the second interface of the second three-way valve 38 is connected to the other end of the second heat exchange channel of the battery-end heat exchanger 4, and the two ends of the second external radiator 40 are connected to the third interface of the second three-way valve 38 and the third pipeline.

[0085] The first interface of the third three-way valve 39 is connected to the third pipeline, the second interface of the second three-way valve 38 is connected to the liquid storage tank 1, and the third interface of the second three-way valve 38 is connected to the second pipeline.

[0086] With such arrangement, when the temperature of the battery pack needs to be lowered, but the temperature of the battery pack is relatively low, it can be achieved by only using the heat dissipation and cooling of the second external radiator 40. Specifically, the first interface of the first three-way valve 37 is controlled to be connected to the second interface, the first interface of the second three-way valve 38 is controlled to be connected to the third interface, and the first interface of the third three-way valve 39 is controlled to be connected to the second interface. The carbon dioxide medium in the liquid storage tank 1 flows through the boost pump 2, the first three-way valve 37, the second pipeline, the battery heat exchange component 3, the second three-way valve 38, the second external radiator 40, the third pipeline and the third three-way valve 39 in sequence, and then flows back to the liquid storage tank 1. After the carbon dioxide medium absorbs the heat of the battery pack in the battery heat exchange component 3, it dissipates heat at the second external radiator 40.

[0087] When the temperature of the battery pack needs to be lowered, and the temperature of the battery pack is relatively high, and the heat dissipation effect of the second external radiator 40 cannot meet the demand, the heat pump air conditioning system can be used to cool the battery thermal management system. Specifically, the first interface of the first three-way valve 37 is controlled to be connected to the second interface, the first interface of the second three-way valve 38 is connected to the second interface, and the first interface of the third three-way valve 39 is connected to the second interface. The carbon dioxide medium in the liquid storage tank 1 flows through the boost pump 2, the first three-way valve 37, the second pipeline, the battery heat exchange component 3, the second three-way valve 38, the battery end heat exchanger 4 and the third three-way valve 39 in sequence, and then flows back to the liquid storage tank 1. After the carbon dioxide medium absorbs the heat of the battery pack in the battery heat exchange component 3, it is then cooled and cooled in the battery end heat exchanger 4.

[0088] When cooling the battery pack, the two-phase cycle pressure-enthalpy diagram of the carbon dioxide medium is referenced Figure 6, where 1-2 is the process of the liquid carbon dioxide medium being pressurized by the boost pump 2, and the carbon dioxide medium output by the boost pump 2 is still in the liquid phase; 2-3 is the process of the carbon dioxide medium entering the battery heat exchange component 3 for evaporation, and the carbon dioxide medium absorbs heat during phase change and will be transformed into a gas phase or a two-phase state; 3-4 is the process of the carbon dioxide medium with a higher dryness from the outlet of the battery heat exchange component 3 to the inlet of the battery end heat exchanger 4 or the inlet of the second external radiator 40 to overcome the pipeline resistance; 4-1 is the process of the carbon dioxide medium from the battery end heat exchanger 4 or the second external radiator 40 to the inlet of the boost pump 2, including the condensation in the battery end heat exchanger 4 or the second external radiator 40 and the process of separating the pure liquid carbon dioxide medium from the liquid storage tank 1, and the carbon dioxide medium releases heat during phase change and will be transformed into a liquid phase.

[0089] When the battery pack needs to be heated, the heat pump air conditioning system needs to be used to heat the battery thermal management system. Specifically, the first interface of the first three-way valve 37 is controlled to be connected to the third interface, the first interface of the second three-way valve 38 is connected to the second interface, and the second interface of the third three-way valve 39 is connected to the third interface. The carbon dioxide medium in the liquid storage tank 1 flows through the boost pump 2, the first three-way valve 37, the third pipeline, the battery end heat exchanger 4, the second three-way valve 38, the battery heat exchange assembly 3 and the third three-way valve 39 in sequence, and then flows back to the liquid storage tank 1. The carbon dioxide medium releases heat in the battery heat exchange assembly 3, and then is heated and heated in the battery end heat exchanger 4.

[0090] When heating the battery pack, the two-phase cycle pressure-enthalpy diagram of the carbon dioxide medium is referenced Figure 7 , where 1-2 is the process of the liquid phase carbon dioxide medium being pressurized by the boost pump 2, and the carbon dioxide medium output by the boost pump 2 is still in the liquid phase; 2-3 is the process of the carbon dioxide medium entering the battery end heat exchanger 4 or the second external radiator 40 for evaporation, and the carbon dioxide medium absorbs heat during phase change and will be transformed into a gas phase or a two-phase state; 3-4 is the process of the carbon dioxide medium with a higher dryness from the outlet of the battery end heat exchanger 4 or the second external radiator 40 to the inlet of the battery heat exchange component 3 to overcome the pipeline resistance; 4-1 is the process of the carbon dioxide medium from the inlet of the battery heat exchange component 3 to the inlet of the boost pump 2, and the carbon dioxide medium releases heat during phase change and will be transformed into a liquid phase.

[0091] In summary, the electric vehicle thermal management system provided by the embodiment of the present invention combines the heat pump air conditioning system, the in-vehicle heat exchange circuit and the battery thermal management system to realize an integrated overall thermal management system. The electric vehicle thermal management system provided by the embodiment of the present invention can realize the cooling of the passenger compartment in the vehicle alone, the cooling of the battery pack alone, the heat dissipation cooling of the battery pack, the cooling of the passenger compartment and the battery pack in the vehicle at the same time, the heating of the passenger compartment in the vehicle alone, the heating of the battery pack alone, and the heating of the passenger compartment and the battery pack in the vehicle at the same time, so as to meet the multifunctional thermal management requirements of the passenger compartment and the battery pack in the vehicle.

[0092] Moreover, the battery thermal management system and the thermal runaway protection system of the battery pack are coupled together to reduce system redundancy and simplify the structure of the thermal management system of the electric vehicle. When a thermal runaway warning occurs, fire safety can be achieved by systematically filling the battery pack with carbon dioxide medium.

[0093] 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 it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thermal management system for an electric vehicle, characterized in that: include: Heat pump air conditioning system; A battery thermal management system, comprising at least a liquid storage tank (1), a booster pump (2) and a battery heat exchange component (3) connected to form a loop, wherein the battery heat exchange component (3) is suitable for performing heat exchange with a battery pack, and the battery thermal management system is filled with a subcritical carbon dioxide medium; The battery end heat exchanger (4) comprises a first heat exchange channel and a second heat exchange channel capable of performing heat exchange, the first heat exchange channel being connected to the heat pump air conditioning system, the second heat exchange channel being connected to the battery thermal management system, and the second heat exchange channel being located between the battery heat exchange assembly (3) and the liquid storage tank (1).

2. The electric vehicle thermal management system according to claim 1, characterized in that: The battery pack comprises: A first housing (5) having an interior containing a storage space for accommodating a battery module; A first filling mechanism (6) is arranged inside the first housing (5), and is suitable for filling the first housing (5) with carbon dioxide medium. The first filling mechanism (6) is connected to the outlet end of the booster pump (2) via a first filling pipeline (7). A first control valve (8) is arranged on the first filling pipeline (7), and the first control valve (8) is suitable for controlling the on-off state of the first filling pipeline (7).

3. The electric vehicle thermal management system according to claim 2, characterized in that: The first filling mechanism (6) comprises: The filling main pipe (9) is provided with a plurality of filling ports (10), wherein the plurality of filling ports (10) are spaced apart on the filling main pipe (9), and the middle portion of the filling main pipe (9) is connected to the first filling pipeline (7).

4. The electric vehicle thermal management system according to claim 2, characterized in that: The battery module comprises a plurality of battery cells (11), the battery cells (11) having temperature-sensing nozzles (12) and temperature-sensing elements, the temperature-sensing nozzles (12) being adapted to switch to an open state when the temperature of the battery cells (11) is greater than a first preset temperature value, so as to allow the high-temperature medium in the battery cells (11) to be ejected; The temperature sensing element is electrically connected to the first control valve (8), and the first control valve (8) is adapted to switch to an open state when the temperature of the battery cell (11) is greater than a second preset temperature value, so as to allow the carbon dioxide medium in the battery thermal management system to enter the interior of the first housing (5).

5. The electric vehicle thermal management system according to claim 4, characterized in that: The first housing (5) is provided with a first pressure relief valve (13), and the first pressure relief valve (13) is adapted to switch to an open state when the pressure in the first housing (5) reaches a first preset pressure value, so as to allow the first housing (5) to release pressure; A plurality of the first pressure relief valves (13) are provided, and the plurality of the first pressure relief valves (13) are provided at one end of the first housing (5) close to the temperature sensing nozzle (12), and the plurality of the first pressure relief valves (13) are distributed at intervals on the first housing (5).

6. The electric vehicle thermal management system according to claim 1, characterized in that: The heat pump air conditioning system comprises: A heat pump circuit comprises a compressor (14), a four-way valve (15), a first external radiator (16), a first expansion valve (17), a second expansion valve (18), an internal heat exchanger (19) and a gas-liquid separator (20), wherein the refrigerant filled in the heat pump circuit is flammable; a second housing (21) having a storage space therein, wherein at least the compressor (14), the four-way valve (15), the first expansion valve (17), the second expansion valve (18), the in-vehicle heat exchanger (19) and the gas-liquid separator (20) are arranged inside the second housing (21); The second filling mechanism (22) is arranged inside the second housing (21), and is suitable for filling the interior of the second housing (21) with carbon dioxide medium. The second filling mechanism (22) is connected to the outlet end of the booster pump (2) via a second filling pipeline (23). The second filling pipeline (23) is provided with a second control valve (24), and the second control valve (24) is suitable for controlling the on-off state of the second filling pipeline (23).

7. The electric vehicle thermal management system according to claim 6, characterized in that: The heat pump air conditioning system also includes: a temperature detection element (25) disposed inside the second housing (21), the temperature detection element (25) being adapted to detect the temperature inside the second housing (21), the temperature detection element (25) being electrically connected to the second control valve (24), the second control valve (24) being adapted to switch to an open state when the temperature inside the second housing (21) is greater than a third preset temperature value, so as to allow the carbon dioxide medium in the battery thermal management system to enter the interior of the second housing (21); A second pressure relief valve (26) is arranged in the second housing (21); the second pressure relief valve (26) is adapted to switch to an open state when the pressure in the second housing (21) reaches a second preset pressure value, so as to release the pressure in the second housing (21); the second pressure relief valve (26) and the second filling mechanism (22) are distributed at two opposite ends of the second housing (21).

8. The electric vehicle thermal management system according to claim 6, characterized in that: The first external radiator (16) is arranged outside the second housing (21), and the heat pump air conditioning system further comprises: A third charging mechanism (27) is arranged around the first external radiator (16), and is suitable for charging carbon dioxide medium into the first external radiator (16). The third charging mechanism (27) is connected to the outlet end of the boost pump (2) via a third charging pipeline (28). A third control valve (29) is arranged on the third charging pipeline (28), and the third control valve (29) is suitable for controlling the on-off state of the third charging pipeline (28).

9. The electric vehicle thermal management system according to claim 6, characterized in that: The heat pump air conditioning system also includes: An off-vehicle heat exchanger (30) is arranged inside the second housing (21), and comprises a third heat exchange channel and a fourth heat exchange channel capable of performing heat exchange, one end of the third heat exchange channel is connected to the four-way valve (15), and the other end of the third heat exchange channel is connected to the first expansion valve (17) and the second expansion valve (18), and the fourth heat exchange channel is connected to the first off-vehicle radiator (16) to form an off-vehicle heat exchange circuit, and the off-vehicle heat exchanger (30) is suitable for heat exchange between the heat exchange medium in the off-vehicle heat exchange circuit and the refrigerant in the heat pump circuit, and the off-vehicle heat exchange circuit is suitable for heat exchange with air outside the vehicle.

10. The electric vehicle thermal management system according to claim 2, characterized in that: The battery heat exchange component (3) is configured as a cover plate (31) of the first housing (5); Alternatively, the battery heat exchange component (3) is arranged inside the first housing (5), and the battery heat exchange component (3) comprises: At least two first heat exchange plates (32) are provided, each of the first heat exchange plates (32) is spaced apart and distributed along the transverse direction of the first housing (5), each of the first heat exchange plates (32) extends along the longitudinal direction of the first housing (5), and a battery cell (11) of the battery module is suitable for being placed between two adjacent first heat exchange plates (32); A pair of second heat exchange plates (33), each of the first heat exchange plates (32) is located between the pair of the second heat exchange plates (33), and each of the first heat exchange plates (32) is connected to the second heat exchange plate (33), and the pair of the second heat exchange plates (33) are respectively connected to the outlet end of the booster pump (2) and the second heat exchange channel.

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