Thermal management system, thermal management method and electric vehicle

Abstract

This invention relates to a thermal management system, a thermal management method, and an electric vehicle. The thermal management system includes a compressor, an air heater, an external heat exchange branch with an external heat exchanger, a first internal heat exchange branch with a first internal heat exchanger, a second internal heat exchange branch with a second internal heat exchanger, a battery cooling branch, and a battery heating branch. The first ends of the second internal heat exchange branch, the battery cooling branch, and the battery heating branch are connected together. The second ends of the second internal heat exchange branch and the battery cooling branch are connected to the compressor air inlet, and the second end of the battery heating branch is connected to the first internal heat exchange branch. The first end of the external heat exchange branch is connected to the first end of the battery heating branch, and its second end is connected to the compressor air inlet. The first end of the first internal heat exchange branch is connected to the first end of the second internal heat exchange branch, and its second end is connected to the compressor exhaust port.

Description

Technical Field

[0001] This invention relates to the field of thermal management for electric vehicles, and more specifically, to a thermal management system, a thermal management method, and an electric vehicle equipped with the thermal management system for electric vehicles. Background Technology

[0002] Traditional gasoline-powered vehicles rely on the heat from their engines for heating and air conditioning. However, new energy vehicles (such as electric vehicles) lack engines that generate significant heat, necessitating the use of other methods, typically PTC heaters and heat pumps. The main problems with PTC heaters are their low efficiency and high power consumption, negatively impacting the driving range of electric vehicles. Furthermore, in cold winter weather, the activity of the materials within the electric vehicle's battery decreases, resulting in low battery discharge efficiency and further reducing the driving range.

[0003] Currently, under low-temperature conditions, the thermal management system of electric vehicles primarily heats the battery through water-based PTC heaters or motor stall. As vehicle voltage increases, the cost of water-based PTC heaters rises, and the heat for heating the battery originates from the battery itself, thus affecting the vehicle's driving range. Regarding heating the battery through motor stall, the secondary heat exchange and heat loss through the piping result in low heating efficiency, which also impacts vehicle energy consumption and driving range.

[0004] Under low-temperature conditions, the thermal management system mainly heats the passenger compartment through air PTC heaters and heat pumps. However, at extremely low temperatures (i.e., below -20°C), heating can only be achieved through air PTC heaters. But due to the limitations of the power of the air PTC heaters and the operating range of the heat pumps, the heating time of the passenger compartment is limited, which is detrimental to the user experience. Summary of the Invention

[0005] The purpose of this invention is to provide a thermal management system for electric vehicles that overcomes the above-mentioned disadvantages. Through this invention, the performance of the thermal management system under extreme low temperature and low temperature conditions is improved, the energy consumption of the thermal management system is reduced, and the rate and energy of battery heating and passenger compartment heating are increased.

[0006] Furthermore, the present invention aims to solve or alleviate other technical problems existing in the prior art.

[0007] According to a first aspect of the present invention, the technical solution adopted by the present invention to solve the technical problem is to provide a thermal management system for an electric vehicle, comprising: a compressor; an air heater capable of operating independently of the compressor; an external heat exchange branch having an external heat exchanger thereon; a first internal heat exchange branch having a first internal heat exchanger thereon; a second internal heat exchange branch having a second internal heat exchanger thereon; a battery cooling branch having a battery cooler thereon; and a battery heating branch having a liquid cooler thereon, wherein the second internal heat exchange branch, the electric vehicle, and the battery heating branch are all equipped with a liquid cooler. The first end of the battery cooling branch and the first end of the battery heating branch are connected together. The second end of the second compartment heat exchange branch and the second end of the battery cooling branch are connected to the air inlet of the compressor. The second end of the battery heating branch is connected to the first compartment heat exchange branch between the first compartment heat exchanger and the second end of the first compartment heat exchange branch. The first end of the external heat exchange branch is connected to the first end of the battery heating branch, and the second end of the external heat exchange branch is connected to the air inlet of the compressor. The first end of the first compartment heat exchange branch is connected to the first end of the second compartment heat exchange branch, and the second end of the first compartment heat exchange branch is connected to the exhaust port of the compressor.

[0008] Optionally, according to one embodiment of the present invention, the external heat exchange branch is configured to be controlled to be switched on and off, the first internal heat exchange branch is configured to be controlled to be switched on and off, the second internal heat exchange branch is configured to be controlled to be throttled and switched on and off, the battery cooling branch is configured to be controlled to be throttled and switched on and off, and the battery heating branch is configured to be controlled to be switched on and off.

[0009] Optionally, according to one embodiment of the present invention, a first one-way valve is disposed between the first end of the first chamber heat exchange branch and the first chamber heat exchanger of the first chamber heat exchange branch to allow flow from the second end of the first chamber heat exchange branch to the first end of the first chamber heat exchange branch, while a second one-way valve is disposed on the line between the first end of the external heat exchange branch and the first end of the second chamber heat exchange branch to allow flow from the first end of the external heat exchange branch to the first end of the second chamber heat exchange branch.

[0010] Optionally, according to one embodiment of the present invention, the thermal management system further includes a battery waste heat recovery circuit and a motor waste heat recovery circuit, and the battery waste heat recovery circuit and the motor waste heat recovery circuit are connected together by a five-way valve.

[0011] Optionally, according to one embodiment of the present invention, the battery waste heat recovery circuit includes a first pump, a battery, and a battery cooler connected in sequence, while the motor waste heat recovery circuit includes a second pump, a motor assembly consisting of a front motor and a rear motor connected in parallel, and the battery cooler connected in sequence.

[0012] Optionally, according to one embodiment of the present invention, the thermal management system further includes a radiator branch having a radiator located thereon, and a first end of the radiator branch being connected to the five-way valve, while a second end of the radiator branch is connected to the motor waste heat recovery circuit between the battery cooler and the second pump.

[0013] Optionally, according to one embodiment of the present invention, the first ends of the second chamber heat exchange branch, the battery cooling branch, and the battery heating branch are connected together via a three-way valve to achieve selectable three-way or two-way conduction.

[0014] According to a second aspect of the present invention, a thermal management method is provided for the aforementioned thermal management system, and includes: a first extreme cryogenic passenger compartment and a battery heating mode, which relates to a refrigerant circuit consisting of the battery cooling branch and the battery heating branch, wherein the air heater is energized to generate heat to heat the passenger compartment, and the compressor is started such that high-temperature, high-pressure gaseous refrigerant flowing from the exhaust port of the compressor flows through the liquid cooler, flows through the battery cooler, and flows into the compressor; and wherein the extreme cryogenic temperature is an ambient temperature from -30°C to -20°C.

[0015] Optionally, according to one embodiment of the present invention, the above-described thermal management method further includes: a second extreme cryogenic passenger compartment and battery heating mode, which involves a refrigerant circuit consisting of a first in-cabin heat exchange branch, the battery cooling branch, and the battery heating branch, wherein the first in-cabin heat exchange branch and the battery heating branch are connected in parallel with respect to the battery cooling branch, wherein when the battery is heated to half the temperature at which the battery can be normally charged and discharged in the first extreme cryogenic passenger compartment and battery heating mode, the compressor is started, such that a portion of the high-temperature, high-pressure gaseous refrigerant flowing from the exhaust port of the compressor flows through the first in-cabin heat exchanger, flows through the battery cooler, and flows into the compressor; another portion of the high-temperature, high-pressure gaseous refrigerant flows through the liquid cooler, merges with the portion flowing through the first in-cabin heat exchanger, flows through the battery cooler, and flows into the compressor; wherein the air heater is energized to generate heat to supplement the heating of the passenger compartment.

[0016] According to a third aspect of the present invention, a thermal management method is provided for the aforementioned thermal management system, and includes: a cryogenic crew compartment and a battery heating mode, which involves a refrigerant circuit consisting of a first in-cabin heat exchange branch, the external heat exchange branch, and the battery heating branch, wherein the first in-cabin heat exchange branch and the battery heating branch are connected in parallel with respect to the external heat exchange branch, wherein a portion of the high-temperature, high-pressure gaseous refrigerant flowing from the exhaust port of the compressor flows through the first in-cabin heat exchanger, flows through the external heat exchanger, and flows into the compressor; another portion of the high-temperature, high-pressure gaseous refrigerant flows through the liquid cooler, merges with the portion flowing through the first in-cabin heat exchanger, flows through the external heat exchanger, and flows into the compressor; and wherein the cryogenic temperature is an ambient temperature from -20°C to -10°C.

[0017] According to a fourth aspect of the present invention, a thermal management method is provided for the aforementioned thermal management system, and includes: a waste heat recovery passenger compartment heating mode, which involves a refrigerant circuit consisting of a first in-cabin heat exchange branch, the three-way valve, and the battery cooling branch, and a coolant circuit consisting of the battery waste heat recovery circuit, the five-way valve, and the motor waste heat recovery circuit, wherein high-temperature, high-pressure gaseous refrigerant flowing from the exhaust port of the compressor flows through the first in-cabin heat exchanger, flows through the three-way valve and the battery cooler, and flows into the compressor; in the battery waste heat recovery circuit, coolant flows through the battery, flows through the five-way valve, and flows through the battery cooler; and in the motor waste heat recovery circuit, coolant flows through the motor assembly, flows through the five-way valve, and flows through the battery cooler; wherein an air heater is energized to generate heat to supplement the heating of the passenger compartment; and wherein, in the waste heat recovery passenger compartment heating mode, the ambient temperature is from -10°C to 10°C.

[0018] According to a fifth aspect of the present invention, a thermal management method is provided for the aforementioned thermal management system, and includes: a high-temperature crew compartment and a battery cooling mode, which involves a refrigerant circuit consisting of the external heat exchange branch, a second internal heat exchange branch, the three-way valve, and the battery cooling branch, wherein the second internal heat exchange branch and the battery cooling branch are connected in parallel relative to the external heat exchange branch, wherein high-temperature, high-pressure gaseous refrigerant flowing from the exhaust port of the compressor flows through the external heat exchanger, and then a portion of medium-temperature, high-pressure liquid refrigerant flowing from the external heat exchanger flows through the second internal heat exchanger and flows into the compressor; another portion of the medium-temperature, high-pressure liquid refrigerant flowing from the external heat exchanger flows through the three-way valve and the battery cooler and flows into the compressor; and wherein the high temperature is an ambient temperature above 35°C.

[0019] According to a sixth aspect of the present invention, an electric vehicle is provided having a thermal management system for an electric vehicle as described above.

[0020] Compared with existing technologies, the thermal management system, thermal management method, and electric vehicle of the present invention have the following beneficial effects: by adding a liquid cooler and a three-way valve to the refrigerant circuit, heat from the environment is introduced into the thermal management system to heat the battery, thereby reducing energy consumption and further improving the driving range of the electric vehicle at low temperatures and enhancing the overall vehicle power performance; by controlling the mode of the three-way valve, the operating range of the heat pump is extended to about -30°C, thereby achieving rapid heating of the passenger compartment under low-temperature conditions and improving the user experience.

[0021] In the following description of the accompanying drawings and detailed embodiments, details of one or more embodiments of the invention will be set forth. Other features, objects, and advantages of the invention will become apparent from these descriptions, drawings, and claims. Attached Figure Description

[0022] The invention can be described in more detail with reference to the accompanying drawings, which are not drawn to scale. In the drawings:

[0023] Figure 1 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown;

[0024] Figure 2 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in a first extreme cryogenic occupant compartment and battery heating mode;

[0025] Figure 3A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in a second extreme cryogenic occupant compartment and battery heating mode;

[0026] Figure 4 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in cryogenic cabin and battery heating mode;

[0027] Figure 5 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in a waste heat recovery crew compartment heating mode; and

[0028] Figure 6 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in a high-temperature crew compartment and battery cooling mode. Detailed Implementation

[0029] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0030] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive. Furthermore, the terms "first," "second," "third," and similar expressions are used for descriptive and distinguishing purposes only and should not be construed as indicating or implying the relative importance of the corresponding components.

[0031] like Figure 1 A schematic diagram of a thermal management system according to an embodiment of the present invention is clearly shown. The thermal management system mainly consists of five heat exchange branches: an external heat exchange branch, a first internal heat exchange branch, a second internal heat exchange branch, a battery cooling branch, and a battery heating branch. Additionally, the thermal management system includes a compressor 7 and an air heater. Specifically, the air PTC heater 2 can operate independently of the compressor 7 and is used to heat the passenger compartment of the electric vehicle at extremely low temperatures, wherein the extreme low temperature is an ambient temperature ranging from -30°C to -20°C.

[0032] In the thermal management system, compressor 7 can pressurize a low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant. This refrigerant is a cooling medium that absorbs heat during vaporization and releases heat during liquefaction, and in electric vehicles, it can be, for example, Freon, R134a, R1234yf, or carbon dioxide.

[0033] In addition, an external condenser 1 is installed in the external heat exchange branch, an internal condenser 3 is installed in the first internal heat exchange branch, an evaporator 4 is installed in the second internal heat exchange branch, a battery cooler 5 is installed in the battery cooling branch, and a liquid cooler 6 is installed in the battery heating branch.

[0034] Furthermore, such as Figure 1 As shown, the first ends of the second internal heat exchange branch, the battery cooling branch, and the battery heating branch are connected together via a three-way valve 8. The second ends of the second internal heat exchange branch and the battery cooling branch are connected to the air inlet of the compressor 7. The second end of the battery heating branch is connected to the first internal heat exchange branch between the internal condenser 3 and the second end of the first internal heat exchange branch. Furthermore, the first end of the external heat exchange branch is connected to the first end of the battery heating branch, and its second end is connected to the air inlet of the compressor 7. The first end of the first internal heat exchange branch is connected to the three-way valve 8, and its second end is connected to the exhaust port of the compressor 7.

[0035] To meet the heat exchange function of the heat pump system and enable switching between different operating modes, solenoid valves (SOV) with on / off functions, electronic expansion valves (EXV) with throttling and on / off functions, and thermostatic expansion valves (TXV) with throttling and on / off functions can be installed on the corresponding branches and between branches. In addition, to ensure unidirectional flow of refrigerant within the corresponding refrigerant circuit branches and between different branches, check valves can also be installed on the corresponding branches and between branches to prevent refrigerant backflow.

[0036] Specifically, such as Figure 1 As shown, regarding the external heat exchange branch with external condenser 1, a first solenoid valve 18 is installed on the line between its second end and the air inlet of compressor 7, and a second solenoid valve 19 is installed on the line between its second end and the exhaust port of compressor 7. In addition, a third solenoid valve 20 is installed between the internal condenser 3 of the first internal heat exchange branch and the second end of the first internal heat exchange branch.

[0037] A first electronic expansion valve 21 is installed between the first end of the battery cooling branch and the battery cooler 5 of the battery cooling branch, while a second electronic expansion valve 22 is installed on the line between the first end of the external heat exchange branch and the first end of the battery heating branch. In addition, a thermal expansion valve 23 is installed between the first end of the second internal heat exchange branch and the evaporator 4 of the second internal heat exchange branch.

[0038] Furthermore, the first check valve 24 is located between the first end of the first heat exchange branch in the first compartment and the internal condenser of the first heat exchange branch in the first compartment, while the second check valve 25 is located on the line between the first end of the heat exchange branch outside the compartment and the first end of the heat exchange branch inside the second compartment.

[0039] like Figure 1 As shown, in addition to the five heat exchange branches mentioned above, the thermal management system may also include a battery waste heat recovery circuit and a motor waste heat recovery circuit, and the battery waste heat recovery circuit and the motor waste heat recovery circuit can be connected together through a five-way valve 9.

[0040] Specifically, the battery waste heat recovery circuit includes a first pump 14, a battery 10, and a battery cooler 5 connected in sequence, while the motor waste heat recovery circuit includes a second pump 15 connected in sequence, a motor assembly consisting of a front motor 11 and a rear motor 12 connected in parallel, and a battery cooler 5.

[0041] Additionally, both the first pump 14 and the second pump 15 have a power of 110W and are used to pump coolant from the storage tank 17 to circulate the coolant in the battery waste heat recovery circuit and the motor waste heat recovery circuit. Of course, the first pump 14 and the second pump 15 may also have different power ratings, as long as they meet the corresponding operational requirements of the battery waste heat recovery circuit and the motor waste heat recovery circuit. The coolant is preferably water, or other coolants, such as hydraulic oil, that will not cause corrosion or damage to the components of the battery waste heat recovery circuit and the motor waste heat recovery circuit. The motor assembly also includes a controller 13 that controls the operation of the front motor 11 and the rear motor 12, and the controller 13 is disposed in the branch line with the front motor 11.

[0042] also, Figure 1 The thermal management system shown may further include a radiator branch having a radiator 16 thereon. A first end of the radiator branch is connected to a five-way valve 9, while its second end is connected to a motor waste heat recovery circuit between the battery cooler 5 and the second pump 15. The radiator branch also has a storage tank 17 disposed between the radiator 16 and its second end. The storage tank 17 stores the aforementioned coolant.

[0043] In addition, the radiator 16 can be used to exchange heat between the coolant and the air, thereby reducing the temperature of the coolant. Of course, in order to improve the heat dissipation efficiency of the radiator 16, a radiator fan can also be installed around the radiator 16 to blow away the hot air around the radiator 16.

[0044] Next, we will refer to Figure 2-6 Various thermal management methods according to embodiments of the present invention will be described in detail below. Specifically, in these figures, solid lines represent the state where the flow path is open, while dashed lines represent the state where the flow path is closed.

[0045] See Figure 2 , Figure 2 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in a first extreme low temperature crew compartment and battery heating mode, and extreme low temperature refers to an ambient temperature from -30°C to -20°C.

[0046] In the conventional heating mode of the thermal management system of electric vehicles, heat cannot be effectively drawn from the ambient air under extreme low temperatures. Furthermore, the heating demand of the passenger compartment is typically very high under extreme low temperatures, while the heat load demanded by the battery during fast charging is also typically very large. Therefore, by setting the thermal management system to a first extreme low-temperature passenger compartment and battery heating mode, the heating requirements of the passenger compartment and battery under extreme low-temperature conditions can be met.

[0047] Specifically, the first extreme cryogenic crew compartment and battery heating mode involves a refrigerant circuit consisting of a battery cooling branch, a three-way valve 8, and a battery heating branch. Specifically, the third solenoid valve 20 is open in a conducting state, and the first electronic expansion valve 21 is open in a throttling state. Apart from this, all other solenoid valves, electronic expansion valves, and thermal expansion valves are closed.

[0048] In extremely low temperature conditions, the air PTC heater 2 is energized to generate heat to heat the passenger compartment. Simultaneously, the compressor 7 starts, causing high-temperature, high-pressure gaseous refrigerant flowing from the compressor 7's exhaust port to flow through the liquid cooler 6, heating the coolant flowing through it. Specifically, driven by the first pump 14, the coolant flows sequentially through the battery 10, the five-way valve 9, and the liquid cooler 6, where it is heated and, upon flowing through the battery 10, heats the battery 10. In this configuration, the battery heating circuit includes the first pump 14, the battery 10, the five-way valve 9, and the liquid cooler 6.

[0049] The medium-temperature, high-pressure liquid refrigerant, obtained after exothermic reaction, flows through the three-way valve 8 and, after being throttled by the first electronic expansion valve 21, becomes a low-temperature, low-pressure liquid refrigerant. Next, this low-temperature, low-pressure liquid refrigerant flows through the battery cooler 5, where it absorbs heat and evaporates into a low-temperature, low-pressure gaseous refrigerant. Finally, this low-temperature, low-pressure gaseous refrigerant flows into the compressor 7.

[0050] In this first extreme low-temperature passenger compartment and battery heating mode, the thermal management system does not obtain heat from the external environment or the electric vehicle's coolant; instead, the system's heat originates from the air PTC heater and the work done by the compressor. Specifically, the heat from the air PTC heater is used to heat the passenger compartment, while the heat from the compressor's work is used to heat the battery.

[0051] When battery 10 is heated to a predetermined temperature (e.g., half the temperature at which battery 10 can be normally charged and discharged (e.g., 25°C) - 12.5°C) in the first extreme cryogenic passenger compartment and battery heating mode, the thermal management system enters the second extreme cryogenic passenger compartment and battery heating mode. For more information on the second extreme cryogenic passenger compartment and battery heating mode, see [link to relevant documentation]. Figure 3 , Figure 3 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in a second extreme cryogenic occupant compartment and battery heating mode.

[0052] Specifically, the second extreme cryogenic crew compartment and battery heating mode involves a refrigerant circuit consisting of a first compartment heat exchange branch, a three-way valve 8, a battery cooling branch, and a battery heating branch, with the first compartment heat exchange branch and the battery heating branch connected in parallel with respect to the battery cooling branch. Specifically, the third solenoid valve 20 is open in a conducting state, and the first electronic expansion valve 21 is open in a throttling state. Apart from these, all other solenoid valves, electronic expansion valves, and thermal expansion valves are closed.

[0053] In extremely low-temperature conditions, the air PTC heater 2 is energized to generate heat to supplement the heating of the passenger compartment. Simultaneously, the compressor 7 starts, causing a portion of the high-temperature, high-pressure gaseous refrigerant flowing from the compressor 7's exhaust port to flow through the internal condenser 3 and, optionally, the first one-way valve 24. As it flows through the internal condenser 3, the high-temperature, high-pressure gaseous refrigerant transforms into a medium-temperature, high-pressure liquid refrigerant, releasing heat in the process to heat the passenger compartment.

[0054] The medium-temperature, high-pressure liquid refrigerant, obtained after exothermic reaction, flows through the three-way valve 8 and, after being throttled by the first electronic expansion valve 21, becomes a low-temperature, low-pressure liquid refrigerant. Next, this low-temperature, low-pressure liquid refrigerant flows through the battery cooler 5, where it absorbs heat and evaporates into a low-temperature, low-pressure gaseous refrigerant. Finally, this low-temperature, low-pressure gaseous refrigerant flows into the compressor 7.

[0055] Another portion of the high-temperature, high-pressure gaseous refrigerant flows through the liquid cooler 6, merges with the portion flowing through the internal condenser 3 in the three-way valve 8, flows through the battery cooler 5, and flows into the compressor 7. During this flow, the refrigerant's vaporization (absorbing heat) and liquefaction (releasing heat), as well as the coolant's heating of the battery, are the same as the corresponding processes in the first extreme cryogenic crew compartment and battery heating mode, and will not be described in detail here.

[0056] In this second extreme low-temperature passenger compartment and battery heating mode, similarly, the thermal management system does not obtain heat from the external environment or the electric vehicle's coolant; instead, the system's heat originates from the work done by the air PTC heater and the compressor. A portion of the heat from the compressor's work is used to heat the passenger compartment, and another portion is used to heat the battery, while the heat from the air PTC heater is only used to supplement the heating of the passenger compartment.

[0057] Next, turn Figure 4 , Figure 4 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in cryogenic occupant compartment and battery heating mode, and cryogenic refers to an ambient temperature from -20°C to -10°C.

[0058] In low-temperature conditions, there is a heating requirement in both the passenger compartment and the battery. Therefore, by setting the thermal management system to a low-temperature passenger compartment and battery heating mode, the heating requirements of the passenger compartment and battery under low-temperature conditions can be met.

[0059] Specifically, the cryogenic crew compartment and battery heating mode involve a refrigerant circuit consisting of a first in-cabin heat exchange branch, a three-way valve 8, an external heat exchange branch, and a battery heating branch, with the first in-cabin heat exchange branch and the battery heating branch connected in parallel with respect to the external heat exchange branch. Specifically, the first solenoid valve 18 and the third solenoid valve 20 are open in a conducting state, and the second electronic expansion valve 22 is open in a throttling state. Apart from these, all other solenoid valves, electronic expansion valves, and thermal expansion valves are closed.

[0060] At low temperatures, the air PTC heater 2 is not energized and therefore does not operate. A portion of the high-temperature, high-pressure gaseous refrigerant flowing from the exhaust port of the compressor 7 flows through the internal condenser 3 and, optionally, the first one-way valve 24. As it flows through the internal condenser 3, the high-temperature, high-pressure gaseous refrigerant transforms into a medium-temperature, high-pressure liquid refrigerant, releasing heat in the process to heat the passenger compartment.

[0061] The medium-temperature, high-pressure liquid refrigerant, obtained after exothermic reaction, flows through the three-way valve 8 and, after being throttled by the second electronic expansion valve 22, becomes a low-temperature, low-pressure liquid refrigerant. Next, this low-temperature, low-pressure liquid refrigerant flows through the external condenser 1 (which essentially functions as an evaporator), causing the refrigerant to absorb heat from the external environment and evaporate into a low-temperature, low-pressure gaseous refrigerant. Finally, this low-temperature, low-pressure gaseous refrigerant flows into the compressor 7.

[0062] Another portion of the high-temperature, high-pressure gaseous refrigerant flows through the liquid cooler 6, merges with the portion flowing through the internal condenser 3, flows through the external condenser 1, and flows into the compressor 7. During this flow, the refrigerant's vaporization (absorbing heat) and liquefaction (releasing heat), as well as the coolant's heating of the battery, are similar to or identical to the corresponding processes in the first extreme cryogenic crew compartment and battery heating mode, and will not be elaborated upon here.

[0063] In this cryogenic crew compartment and battery heating mode, the thermal management system draws heat from the external environment. A portion of the heat from the external environment is used to heat the crew compartment, while another portion is used to heat the battery.

[0064] See also Figure 5 , Figure 5 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in a waste heat recovery crew compartment heating mode, and the waste heat recovery mode is typically performed at an ambient temperature between -10°C and 10°C.

[0065] When there is a heating requirement in the passenger compartment, both the battery and the motor can be in a state that can provide waste heat recovery. Therefore, by setting the thermal management system to a waste heat recovery passenger compartment heating mode, the heating requirements of the passenger compartment can be met.

[0066] Specifically, the waste heat recovery crew compartment heating mode involves a refrigerant circuit consisting of a first in-cabin heat exchange branch, a three-way valve 8, and a battery cooling branch, and a coolant circuit consisting of a battery waste heat recovery circuit, a five-way valve 9, and a motor waste heat recovery circuit. Specifically, the third solenoid valve 20 is open in a conducting state, and the first electronic expansion valve 21 is open in a throttling state. Apart from these, all other solenoid valves, electronic expansion valves, and thermal expansion valves are closed.

[0067] In the case of waste heat recovery, the air PTC heater is energized to generate heat to supplement the heating of the passenger compartment. Simultaneously, a portion of the high-temperature, high-pressure gaseous refrigerant flowing from the exhaust port of compressor 7 flows through the internal condenser 3 and, optionally, the first one-way valve 24. As it flows through the internal condenser 3, the high-temperature, high-pressure gaseous refrigerant transforms into a medium-temperature, high-pressure liquid refrigerant, releasing heat in the process to heat the passenger compartment.

[0068] The medium-temperature, high-pressure liquid refrigerant, obtained after exothermic reaction, flows through the three-way valve 8 and, after being throttled by the first electronic expansion valve 21, becomes a low-temperature, low-pressure liquid refrigerant. Next, this low-temperature, low-pressure liquid refrigerant flows through the battery cooler 5, where it absorbs heat and evaporates into a low-temperature, low-pressure gaseous refrigerant. Finally, this low-temperature, low-pressure gaseous refrigerant flows into the compressor 7.

[0069] In the battery waste heat recovery loop, coolant from storage tank 17 flows through battery 10, through five-way valve 9, and through battery cooler 5. In battery cooler 5, refrigerant from refrigerant loop exchanges heat with coolant and thus absorbs waste heat from battery 10.

[0070] In the motor waste heat recovery loop, coolant from storage tank 17 flows through the motor assembly, through the five-way valve 9, and through the battery cooler 5. Similarly, in the battery cooler 5, refrigerant from the refrigerant loop exchanges heat with the coolant and thus absorbs waste heat from the front motor 11 and the rear motor 12.

[0071] In this waste heat recovery passenger compartment heating mode, the heat of the thermal management system comes from the air PTC heater, as well as the waste heat from the battery and motor. The waste heat from the battery and motor is used to heat the passenger compartment, while the heat from the air PTC heater is only used to supplement the heating of the passenger compartment.

[0072] Finally, see Figure 6 , Figure 6 A schematic diagram of a thermal management system according to an embodiment of the present invention is shown, wherein the thermal management system is in a high-temperature occupant compartment and battery cooling mode, and high temperature refers to an ambient temperature above 35°C.

[0073] Under high-temperature conditions, there is a need for cooling in both the crew compartment and the battery. Therefore, by setting the thermal management system to a high-temperature crew compartment and battery cooling mode, the cooling requirements of the crew compartment and battery under high-temperature conditions can be met.

[0074] Specifically, the high-temperature crew compartment and battery cooling mode involve a refrigerant circuit consisting of an external heat exchange branch, a second internal heat exchange branch, a three-way valve 8, and a battery cooling branch, with the second internal heat exchange branch and the battery cooling branch connected in parallel with the external heat exchange branch. Specifically, the second solenoid valve 19 is open in a conducting state, the thermostatic expansion valve 23 is open in a throttling state, and the first electronic expansion valve 21 is open in a throttling state. Apart from these, all other solenoid valves, electronic expansion valves, and thermostatic expansion valves are closed.

[0075] At high temperatures, the air PTC heater 2 is not energized and therefore does not operate. The high-temperature, high-pressure gaseous refrigerant flowing from the exhaust port of the compressor 7 flows through the external condenser 1 and, optionally, the second one-way valve 25. As it flows through the external condenser 1, the high-temperature, high-pressure gaseous refrigerant transforms into a medium-temperature, high-pressure liquid refrigerant, releasing heat to the external environment in the process.

[0076] A portion of the medium-temperature, high-pressure liquid refrigerant flowing from the external condenser 1 is throttled by the thermostatic expansion valve 23, becoming a low-temperature, low-pressure liquid refrigerant. This low-temperature, low-pressure liquid refrigerant then flows through the evaporator 4, where it absorbs heat from the passenger compartment and evaporates into a low-temperature, low-pressure gaseous refrigerant. During this heat absorption process, the evaporator 4 cools the passenger compartment. Finally, this low-temperature, low-pressure gaseous refrigerant flows into the compressor 7.

[0077] Another portion of the medium-temperature, high-pressure liquid refrigerant flowing from the external condenser 1 flows through the three-way valve 8 and, after being throttled by the first electronic expansion valve 21, becomes a low-temperature, low-pressure liquid refrigerant. This low-temperature, low-pressure liquid refrigerant then flows through the battery cooler 5, where it absorbs heat and evaporates into a low-temperature, low-pressure gaseous refrigerant. Finally, this low-temperature, low-pressure gaseous refrigerant flows into the compressor 7.

[0078] Specifically, driven by the first pump 14, the coolant flows sequentially through the battery 10, the five-way valve 9, and the battery cooler 5, and is cooled in the battery cooler 5, thus cooling the battery 10 as it flows through it. In this case, the battery cooling circuit includes the first pump 14, the battery 10, the five-way valve 9, and the battery cooler 5.

[0079] Alternatively, individual cabin cooling can be achieved by closing the first electronic expansion valve 21, or individual battery cooling can be achieved by closing the thermal expansion valve 23.

[0080] The aforementioned thermal management system for electric vehicles may also include other necessary components to achieve its function (e.g., a heat recovery heat exchanger installed on the external heat exchange branch, a gas-liquid separator installed near the air inlet of the compressor, etc.). These components are well known to those skilled in the art and will not be described in detail here.

[0081] Compared with the prior art, the key point of the thermal management system for electric vehicles in this invention is: by adding a liquid cooler and a three-way valve to the refrigerant circuit, the compressor performs work or introduces heat from the environment into the thermal management system to heat the battery, thereby reducing energy consumption; by controlling the mode of the three-way valve, the operating range of the thermal management system is extended to about -30°C, thereby achieving rapid heating of the passenger compartment under low temperature conditions and improving the user experience.

[0082] The present invention also provides an electric vehicle incorporating the thermal management system. Due to the use of the thermal management system for electric vehicles according to the present invention, the driving range of the electric vehicle at low and extreme low temperatures is significantly improved, and thus its overall vehicle performance is further enhanced.

[0083] It should be understood that the above description is for illustrative purposes only and is not intended to limit the invention. It should be noted that those skilled in the art can make various improvements, modifications, and variations to the invention, but such improvements, modifications, and variations should all be considered to fall within the scope of protection of the invention without departing from its spirit.

[0084] Parts list

[0085] 1. External condenser

[0086] 2. Air PTC heater

[0087] 3. Internal condenser

[0088] 4. Evaporator

[0089] 5. Battery Cooler

[0090] 6. Liquid Cooler

[0091] 7. Compressor

[0092] 8 Three-way valve

[0093] 9. Five-way valve

[0094] 10 batteries

[0095] 11 Front motor

[0096] 12 rear motor

[0097] 13 Controllers

[0098] 14 First Pump

[0099] 15 Second Pump

[0100] 16 Radiators

[0101] 17 Storage Box

[0102] 18 First Solenoid Valve

[0103] 19 Second Solenoid Valve

[0104] 20 Third Solenoid Valve

[0105] 21 First electronic expansion valve

[0106] 22 Second electronic expansion valve

[0107] 23 Thermal expansion valve

[0108] 24 First check valve

[0109] 25 Second check valve.

Claims

1. A thermal management system for an electric vehicle, characterized by, It comprises: a compressor; an air heater operable independently of the compressor; an external heat exchange branch having an external heat exchanger located thereon; a first internal heat exchange branch having a first internal heat exchanger located thereon; a second internal heat exchange branch having a second internal heat exchanger located thereon; a battery cooling branch having a battery cooler located thereon; and a battery heating branch having a liquid-cooled cooler located thereon, wherein a first end of the second internal heat exchange branch, the battery cooling branch and the battery heating branch are connected together, a second end of the second internal heat exchange branch and the battery cooling branch are connected to an air inlet of the compressor, and a second end of the battery heating branch is connected to the first internal heat exchange branch between the first internal heat exchanger and a second end of the first internal heat exchange branch; and wherein a first end of the external heat exchange branch is connected to the first end of the battery heating branch, a second end of the external heat exchange branch is connected to the air inlet of the compressor, and a first end of the first internal heat exchange branch is connected to the first end of the second internal heat exchange branch, and a second end of the first internal heat exchange branch is connected to an air outlet of the compressor, wherein the external heat exchange branch is configured to be controllably switched on and off, the first internal heat exchange branch is configured to be controllably switched on and off, the second internal heat exchange branch is configured to be controllably throttled and switched on and off, the battery cooling branch is configured to be controllably throttled and switched on and off, and the battery heating branch is configured to be controllably switched on and off; and wherein the thermal management system further comprises a battery waste heat recovery loop and a motor waste heat recovery loop, and the battery waste heat recovery loop and the motor waste heat recovery loop are connected together by a five-way valve. A first check valve is provided between the first end of the first internal heat exchange branch and the first internal heat exchanger of the first internal heat exchange branch to allow flow from the second end of the first internal heat exchange branch to the first end of the first internal heat exchange branch, and a second check valve is provided on a line between the first end of the external heat exchange branch and the first end of the second internal heat exchange branch to allow flow from the first end of the external heat exchange branch to the first end of the second internal heat exchange branch.

2. The thermal management system for an electric vehicle of claim 1, wherein, The battery waste heat recovery loop comprises a first pump, a battery and the battery cooler connected end to end in that order, and the motor waste heat recovery loop comprises a second pump, a motor assembly comprising a front motor and a rear motor connected in parallel, and the battery cooler connected end to end in that order.

3. The thermal management system for an electric vehicle of claim 1, wherein, The thermal management system further comprises a radiator branch having a radiator located thereon, and a first end of the radiator branch is connected to the five-way valve, and a second end of the radiator branch is connected to the motor waste heat recovery loop between the battery cooler and the second pump.

4. The thermal management system for an electric vehicle of claim 3, wherein, ​ 5. The thermal management system for an electric vehicle of claim 3, wherein, The first end of the second in-cabin heat exchange branch, the battery cooling branch and the battery heating branch are connected together via a three-way valve to realize selectable three-way or two-way conduction.

6. A thermal management method for the thermal management system of any one of claims 1-5, characterized by, It includes: A first extreme low temperature passenger cabin and battery heating mode, which involves a refrigerant circuit composed of the battery cooling branch and the battery heating branch, Wherein, the air heater is powered to generate heat to heat the passenger cabin, and the compressor is started, so that the high-temperature and high-pressure gaseous refrigerant flowing out of the exhaust port of the compressor flows through the liquid cooling cooler, flows through the battery cooler, and flows into the compressor; and Wherein, the extreme low temperature is an ambient temperature from -30℃ to -20℃.

7. The thermal management method of claim 6, wherein, It also includes: A second extreme low temperature passenger cabin and battery heating mode, which involves a refrigerant circuit composed of the first in-cabin heat exchange branch, the battery cooling branch and the battery heating branch, and the first in-cabin heat exchange branch and the battery heating branch are connected in parallel with respect to the battery cooling branch, Wherein, when the battery is heated to half of the temperature at which the battery can normally charge and discharge in the first extreme low temperature passenger cabin and battery heating mode, the compressor is started, so that part of the high-temperature and high-pressure gaseous refrigerant flowing out of the exhaust port of the compressor flows through the first in-cabin heat exchanger, flows through the battery cooler, and flows into the compressor; another part of the high-temperature and high-pressure gaseous refrigerant flows through the liquid cooling cooler, merges with the part flowing through the first in-cabin heat exchanger, flows through the battery cooler, and flows into the compressor; Wherein, the air heater is powered to generate heat to supplement the heating of the passenger cabin.

8. A thermal management method for the thermal management system of any one of claims 1-5, characterized by, It includes: A low temperature passenger cabin and battery heating mode, which involves a refrigerant circuit composed of a first in-cabin heat exchange branch, the out-of-cabin heat exchange branch and the battery heating branch, and the first in-cabin heat exchange branch and the battery heating branch are connected in parallel with respect to the out-of-cabin heat exchange branch, Wherein, part of the high-temperature and high-pressure gaseous refrigerant flowing out of the exhaust port of the compressor flows through the first in-cabin heat exchanger, flows through the out-of-cabin heat exchanger, and flows into the compressor; another part of the high-temperature and high-pressure gaseous refrigerant flows through the liquid cooling cooler, merges with the part flowing through the first in-cabin heat exchanger, flows through the out-of-cabin heat exchanger, and flows into the compressor; and Wherein, the low temperature is an ambient temperature from -20℃ to -10℃.

9. A thermal management method for the thermal management system of claim 5, characterized by, It includes: A waste heat recovery passenger cabin heating mode, which involves a refrigerant circuit composed of a first in-cabin heat exchange branch, the three-way valve and the battery cooling branch, and a cooling liquid circuit composed of the battery waste heat recovery circuit, the five-way valve and the motor waste heat recovery circuit, wherein high temperature and high pressure gaseous refrigerant flowing out of the discharge port of the compressor flows through the first in-cabin heat exchanger, flows through the three-way valve and the battery cooler, and flows into the compressor; in the battery waste heat recovery circuit, coolant flows through the battery, flows through the five-way valve, and flows through the battery cooler; and in the motor waste heat recovery circuit, the coolant flows through the motor assembly, flows through the five-way valve, and flows through the battery cooler; wherein the air heater is energized to generate heat to supplement heating of the passenger cabin; and wherein in the waste heat recovery passenger cabin heating mode, the ambient temperature is from -10°C to 10°C.

10. A thermal management method for the thermal management system of claim 5, characterized by, which comprises: a high temperature passenger cabin and battery cooling mode involving a refrigerant circuit consisting of the off-cabin heat exchanger branch, the second in-cabin heat exchanger branch, the three-way valve, and the battery cooling branch, wherein the second in-cabin heat exchanger branch and the battery cooling branch are connected in parallel with respect to the off-cabin heat exchanger branch, wherein high temperature and high pressure gaseous refrigerant flowing out of the discharge port of the compressor flows through the off-cabin heat exchanger, then a portion of the medium temperature and high pressure liquid refrigerant flowing out of the off-cabin heat exchanger flows through the second in-cabin heat exchanger and flows into the compressor; another portion of the medium temperature and high pressure liquid refrigerant flowing out of the off-cabin heat exchanger flows through the three-way valve and the battery cooler, and flows into the compressor; and wherein the high temperature in the high temperature passenger cabin is an ambient temperature higher than 35°C.

11. An electric vehicle characterized by comprising: which has a thermal management system for an electric vehicle according to any one of claims 1-5.

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