Electric vehicle thermal management system and control method therefor

Abstract

Provided in the present application are an electric vehicle thermal management system and a control method therefor. The electric vehicle thermal management system comprises a heat pump loop, a waste heat loop and a heat storage bypass; the heat pump loop is successively provided with an evaporator, a compressor, a condenser and a throttle valve in the flow direction of a refrigerant; the waste heat loop is successively provided with a first waste heat pipe, a heat source component, a second waste heat pipe and the evaporator in the flow direction of a cooling liquid; the heat storage bypass is connected in parallel to a branch section of the second waste heat pipe, and the heat storage bypass is provided with a heat storage device. In the electric vehicle thermal management system provided by the present application, a portion of heat released by the heat source component during operation can be transferred to the evaporator by means of the second waste heat pipe, and another portion of the heat can be released by means of the heat storage device in the heat storage bypass, so as to provide heat for vaporization of the refrigerant in the evaporator, thereby ensuring normal operation of the heat pump loop. The present application does not require starting a PTC backup heat source, and thus does not consume additional electric energy of a power battery, thus reducing energy consumption of electric vehicles.

Description

A thermal management system for electric vehicles and its control method

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411187804.7, filed on August 28, 2024, entitled "A Thermal Management System for an Electric Vehicle and a Control Method Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of electric vehicle thermal management technology, and more specifically, to an electric vehicle thermal management system and its control method. Background Technology

[0004] Electric vehicles, as representatives of new energy vehicles, have become a trend in automotive development. Among these, the power battery is the power source for electric vehicles. At low temperatures, the driving range of electric vehicles decreases significantly.

[0005] Currently, in winter driving, electric vehicles typically use high-power heating devices such as water-heated electric heaters (WPTC) to provide heat to the passenger compartment, ensuring the comfort of the driver and passengers. However, these high-power heating devices consume a significant amount of electricity, affecting the driving range of electric vehicles. To address the issue of excessive energy consumption by these high-power heating devices, heat pump systems are introduced into electric vehicles. These systems absorb heat from the outside air or a hot water source through an evaporator, compress the refrigerant using a compressor, and then use a condenser for heat exchange to raise the temperature of the battery or the interior of the vehicle. However, heat pump systems cannot function properly when the ambient temperature or water source temperature is too low, requiring the WPTC to be activated as a backup heat source, resulting in a reduced driving range and higher energy consumption for electric vehicles. Summary of the Invention

[0006] The first aspect of this application provides an electric vehicle thermal management system configured to solve the technical problem in the prior art that when the ambient temperature or water source temperature is too low, the heat pump system cannot work normally and requires the WPTC backup heat source to be activated, resulting in a reduction in the driving range of the electric vehicle and high energy consumption.

[0007] This application provides a thermal management system for an electric vehicle, including:

[0008] The heat pump circuit consists of an evaporator, a compressor, a condenser, and a throttling valve arranged sequentially along the refrigerant flow direction.

[0009] The waste heat circuit includes, in sequence along the flow direction of the coolant, a first waste heat pipe, a heat source component, a second waste heat pipe, and the evaporator; the first and second waste heat pipes are configured to transfer the heat released by the heat source component during operation to the evaporator; and...

[0010] A heat storage bypass is connected in parallel to a branch section of the second waste heat pipeline; the heat storage bypass is equipped with a heat storage device, which is configured to store the heat released by the heat source component and transfer the stored heat to the evaporator.

[0011] This application provides an electric vehicle thermal management system. Firstly, it utilizes waste heat generated by heat source components to provide heat for the vaporization of refrigerant in the evaporator. The refrigerant temperature is increased by compressing it with a compressor. Heat exchange occurs between the refrigerant and the coolant in the heating component circuit in the condenser, forming a heat pump circuit with a heating efficiency higher than that of electric heating. Secondly, since the heat pump circuit cannot operate normally when the ambient temperature or water source temperature is too low, this application connects a parallel heat storage bypass to the waste heat circuit. Part of the heat released by the heat source components during operation can be transferred to the evaporator via a second waste heat pipeline, and the other part can be stored in the heat storage bypass. The heat pump releases heat to the evaporator, and the coolant can absorb some heat through the heat storage tank, increasing the temperature of the coolant entering the evaporator and thus increasing the temperature of the refrigerant in the evaporator, reaching the minimum temperature requirement for the heat pump to operate normally. Thirdly, the heat source components exchange heat with the refrigerant in the evaporator through the coolant, and the refrigerant releases heat in the condenser through the heat pump circuit, which is then used to heat the components to be heated in the electric vehicle. Waste heat is recovered, saving energy. Compared with existing technologies, this application does not require the activation of the WPTC electric heating device, has higher heating efficiency than WPTC, and can reduce the reduction in the electric vehicle's driving range, thereby saving energy consumption.

[0012] Optionally, the input trunk section of the second waste heat pipeline is equipped with a first temperature sensor, configured to detect the coolant temperature at the waste heat output end of the heat source component;

[0013] And / or, the output trunk section of the second waste heat pipeline is equipped with a second temperature sensor, configured to detect the coolant temperature at the inlet of the evaporator.

[0014] Optionally, the second waste heat pipeline is equipped with a three-way valve, which has an inlet end, a first outlet end and a second outlet end. The inlet end is connected to the waste heat output end of the heat source component, the first outlet end is connected to the liquid inlet end of the heat storage tank, and the second outlet end is connected to the liquid inlet end of the evaporator.

[0015] This application provides an electric vehicle thermal management system, which includes a three-way valve. Based on the coolant temperature at the waste heat output end of the heat source component, the system controls the coolant flow direction between the waste heat output end of the heat source component and the evaporator. Specifically, if the coolant temperature at the evaporator inlet is too high, the heat pump circuit cannot operate normally. The system controls the coolant to flow to the evaporator via a heat storage bypass, storing some of the heat released by the heat source component in a heat storage tank, thereby reducing the coolant temperature at the evaporator inlet and facilitating the normal operation of the heat pump circuit. If the coolant temperature at the evaporator inlet is too low, the system controls the coolant to flow to the evaporator via the heat storage bypass and a branch section of the second waste heat pipeline, and controls the opening of the first and second outlets of the three-way valve. The evaporator absorbs heat from the heat storage tank and the waste heat circuit, thereby increasing the coolant temperature at the evaporator inlet and providing heat for the vaporization of the refrigerant in the evaporator. In summary, the technical solution of this application expands the operating temperature range of the heat pump circuit 10.

[0016] Optionally, the second waste heat pipeline is provided with a first valve, which is located between the waste heat output end of the heat source component and the coolant inlet end of the evaporator; the heat storage bypass is provided with a second valve, which is located between the waste heat output end of the heat source component and the coolant inlet end of the heat storage device.

[0017] Optionally, the electric vehicle thermal management system further includes a controller, and the three-way valve is electrically connected to the controller;

[0018] The input trunk section of the second waste heat pipeline is equipped with a first temperature sensor located between the waste heat output end of the heat source component and the inlet end of the three-way valve. This sensor is configured to detect the coolant temperature at the waste heat output end of the heat source component. The first temperature sensor is electrically connected to the controller, which is configured to: control the opening and closing of the first outlet end and the second outlet end of the three-way valve based on the coolant temperature detected by the first temperature sensor at the waste heat output end of the heat source component; and / or, the output trunk section of the second waste heat pipeline is equipped with a second temperature sensor located between the second outlet end of the three-way valve and the coolant inlet end of the evaporator. This sensor is configured to detect the coolant temperature at the inlet end of the evaporator. The second temperature sensor is electrically connected to the controller, which is configured to: control the opening degree of the first outlet end and the second outlet end of the three-way valve based on the coolant temperature detected by the second temperature sensor at the inlet end of the evaporator. This configuration enables the automatic opening and closing of the first and second outlet ends of the three-way valve; and / or enables the automatic adjustment of the opening degree of the first outlet end 242 and the second outlet end 243 of the three-way valve 24.

[0019] Optionally, the electric vehicle thermal management system further includes a controller, wherein both the first valve and the second valve are electrically connected to the controller;

[0020] The input trunk section of the second waste heat pipeline is equipped with a first temperature sensor located between the waste heat output end of the heat source component and the first valve. This sensor is configured to detect the coolant temperature at the waste heat output end of the heat source component. The first temperature sensor is electrically connected to the controller, which is configured to control the opening and closing of the first valve and the second valve based on the coolant temperature detected by the first temperature sensor at the waste heat output end of the heat source component. Alternatively, the output trunk section of the second waste heat pipeline is equipped with a second temperature sensor located between the outlet end of the first valve and the coolant inlet end of the evaporator. This sensor is configured to detect the coolant temperature at the inlet end of the evaporator. The second temperature sensor is electrically connected to the controller, which is configured to control the opening degree of the first valve and the second valve based on the coolant temperature detected by the second temperature sensor at the inlet end of the evaporator.

[0021] Optionally, the electric vehicle thermal management system further includes a heating demand loop, with both ends of the heating demand loop connected to the condenser, configured to absorb the heat released by the condenser, and configured to heat the components to be heated. With this configuration, the heat generated by the electric vehicle's heat source components provides heat to the evaporator of the heat pump circuit, enabling the refrigerant to vaporize in the evaporator, be compressed into a high-temperature, high-pressure gas by the compressor, and then dissipate heat through cooling by the condenser. The condenser is connected to the heating demand loop, and the refrigerant in the condenser releases heat into the coolant of the heating demand loop, configured to heat the components to be heated. Compared with the prior art, this application does not require a WPTC heat source, has higher heating efficiency than WPTC, can reduce the reduction in the electric vehicle's driving range, and thus save energy consumption.

[0022] Optionally, the heating demand circuit includes a first connector and a second connector. The first connector is configured to connect to the liquid outlet of the component to be heated, and the second connector is configured to connect to the liquid inlet of the component to be heated. This configuration allows for the connection of different components to be heated based on actual needs, improving the practicality of the heating demand circuit.

[0023] Optionally, the component to be heated is the passenger compartment or a battery.

[0024] Optionally, the heat source component is a motor or a power battery.

[0025] Optionally, the heat storage device is a phase change heat storage device, and the phase change heat storage device contains a phase change material.

[0026] Optionally, the melting temperature range of the phase change material is between 0°C and 30°C; and / or, the phase change material is an alcohol, paraffin, fatty acid, aromatic hydrocarbon, or polymer.

[0027] A second aspect of this application provides a control method for an electric vehicle thermal management system, configured as described above, the control method comprising the following steps:

[0028] The coolant temperature at the waste heat output end of the heat source component and the preset coolant temperature at the inlet end of the evaporator are obtained.

[0029] If the coolant temperature at the waste heat output end of the heat source component is greater than the maximum value of the preset coolant temperature at the liquid inlet end of the evaporator, then the coolant between the waste heat output end of the heat source component and the liquid inlet end of the evaporator is controlled to flow to the evaporator through the heat storage bypass, and not through the branch section of the second waste heat pipeline.

[0030] If the temperature of the coolant at the waste heat output end of the heat source component falls within the preset temperature range of the coolant at the inlet end of the evaporator, the coolant between the waste heat output end of the heat source component and the inlet end of the evaporator is controlled to flow to the evaporator through a branch section of the second waste heat pipeline, without passing through the heat storage bypass, and the heat pump circuit is controlled to work.

[0031] If the coolant temperature at the waste heat output end of the heat source component is less than the minimum preset coolant temperature at the inlet end of the evaporator, then the coolant between the waste heat output end of the heat source component and the inlet end of the evaporator is controlled to flow to the evaporator through the heat storage bypass and the branch section of the second waste heat pipeline, respectively. The opening degree of the control valve connected to the heat storage bypass is controlled to be a first preset opening degree, and the opening degree of the control valve connected to the branch section of the second waste heat pipeline is controlled to be a second preset opening degree.

[0032] This application provides a control method for an electric vehicle thermal management system. By determining the relationship between the coolant temperature at the waste heat output end of the heat source component and the preset coolant temperature at the inlet end of the evaporator, the coolant temperature at the inlet end of the evaporator is controlled by controlling the coolant flow direction between the waste heat output end of the heat source component and the inlet end of the evaporator.

[0033] Optionally, the control method further includes: acquiring the coolant temperature at the inlet end of the evaporator;

[0034] If the coolant temperature at the waste heat output terminal of the heat source component is greater than the maximum value of the preset coolant temperature at the inlet terminal of the evaporator, then the coolant between the waste heat output terminal of the heat source component and the inlet terminal of the evaporator flows to the evaporator through the heat storage bypass without passing through the branch section of the second waste heat pipeline, the control method further includes the following steps:

[0035] Determine whether the temperature of the coolant at the inlet of the evaporator falls within the preset temperature range of the coolant at the inlet of the evaporator. If so, control the heat pump circuit to work; otherwise, control the heat pump circuit to not work.

[0036] This application provides a control method for an electric vehicle thermal management system, which controls the connection between the first waste heat pipeline and the heat storage bypass, so that the coolant flows to the liquid inlet of the evaporator through the heat storage bypass. This method can store some of the heat released by the heat source components in the heat storage tank, thereby reducing the temperature of the coolant entering the evaporator and facilitating the normal operation of the heat pump circuit.

[0037] Optionally, the control method further includes: acquiring the coolant temperature at the inlet end of the evaporator;

[0038] If the coolant temperature at the waste heat output terminal of the heat source component is less than the minimum preset coolant temperature at the inlet terminal of the evaporator, then the coolant between the waste heat output terminal of the heat source component and the inlet terminal of the evaporator flows to the evaporator via the heat storage bypass and the branch section of the second waste heat pipeline, respectively. After controlling the opening degree of the control valve connecting the heat storage bypass to a first preset opening degree and the opening degree of the control valve connecting the branch section of the second waste heat pipeline to a second preset opening degree, the control method further includes the following steps:

[0039] Determine whether the coolant temperature at the inlet of the evaporator falls within the preset temperature range of the coolant at the inlet of the evaporator. If yes, maintain the first current opening degree and the second current opening degree, and control the heat pump circuit to work; if no, adjust the first current opening degree and the second current opening degree.

[0040] This application provides a control method for an electric vehicle thermal management system. By controlling the connection between the first waste heat pipeline and the heat storage bypass, and controlling the connection between the branch sections of the first waste heat pipeline and the second waste heat pipeline, and adjusting the first current opening degree and the second current opening degree, the coolant flow rate of the heat storage bypass and the coolant flow rate of the branch section of the second waste heat pipeline are controlled, thereby controlling the coolant temperature at the liquid inlet of the evaporator and providing heat for the vaporization of the refrigerant in the evaporator.

[0041] Optionally, the preset temperature range of the coolant at the inlet of the evaporator is [-30℃, 25℃].

[0042] This application provides a control method for an electric vehicle thermal management system, which ensures the normal operation of the heat pump circuit by limiting the preset temperature of the coolant at the inlet of the evaporator. Attached Figure Description

[0043] Figure 1 is a schematic diagram of the structure of an electric vehicle thermal management system provided in an embodiment of this application;

[0044] Figure 2 is a schematic diagram of the structure of an electric vehicle thermal management system provided in an embodiment of this application;

[0045] Figure 3 is a schematic diagram of the first state of an electric vehicle thermal management system provided in an embodiment of this application;

[0046] Figure 4 is a schematic diagram of the second state of an electric vehicle thermal management system provided in an embodiment of this application;

[0047] Figure 5 is a schematic diagram of the third state of an electric vehicle thermal management system provided in an embodiment of this application;

[0048] Figure 6 is a schematic diagram of the fourth state of an electric vehicle thermal management system provided in an embodiment of this application;

[0049] Figure 7 is a flowchart of a control method for an electric vehicle thermal management system provided in an embodiment of this application;

[0050] Figure 8 is a flowchart of a control method for an electric vehicle thermal management system provided in an embodiment of this application;

[0051] Figure 9 is a flowchart of a control method for an electric vehicle thermal management system provided in an embodiment of this application.

[0052] Explanation of reference numerals in the attached diagram: 10. Heat pump circuit; 11. Evaporator; 12. Compressor; 13. Condenser; 14. Throttling valve; 20. Waste heat circuit; 21. First waste heat pipeline; 22. Second waste heat pipeline; 221. Branch section; 222. Input main section; 223. Output main section; 23. Heat source component; 24. Three-way valve; 241. Inlet end; 242. First outlet end; 243. Second outlet end; 25. First valve; 26. Second valve; 27. First temperature sensor; 28. Second temperature sensor; 30. Heat storage bypass; 31. Heat storage tank; 40. Heating demand circuit; 41. First connector; 42. Component to be heated; 43. Second connector. Detailed Implementation

[0053] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to Figures 1-9.

[0054] This application provides an electric vehicle thermal management system. Referring to Figures 1-6, the electric vehicle thermal management system includes a heat pump circuit 10, a waste heat circuit 20, and a heat storage bypass 30. The heat pump circuit 10 is provided with an evaporator 11, a compressor 12, a condenser 13, and a throttle valve 14 in sequence along the refrigerant flow direction. The waste heat circuit 20 is provided with a first waste heat pipe 21, a heat source component 23, a second waste heat pipe 22, and an evaporator 11 in sequence along the coolant flow direction. The first waste heat pipe 21 and the second waste heat pipe 22 are configured to transfer the heat released by the heat source component 23 during operation to the evaporator 11. The heat storage bypass 30 is connected in parallel to a branch section 221 of the second waste heat pipe 22. The heat storage bypass 30 is provided with a heat storage device 31, which is configured to store the heat released by the heat source component 23 and transfer the stored heat to the evaporator 11.

[0055] It should be noted that in Figures 3-6, the arrows indicate the flow directions of the refrigerant and the coolant, respectively.

[0056] It should be noted that the refrigerant flowing through the evaporator 11 flows in the opposite direction to the coolant flowing through the evaporator 11, thus achieving heat exchange.

[0057] It should be noted that in the cooling / heating cycle of heat pump circuit 10, compressor 12 draws in low-temperature, low-pressure refrigerant and compresses it into high-temperature, high-pressure gas. This high-temperature, high-pressure gas is then cooled by condenser 13, releasing heat and lowering the refrigerant's temperature and pressure. The refrigerant then enters evaporator 11 through expansion valve 14, where it vaporizes, thus completing the cooling / heating process. The refrigerant needs to absorb heat to vaporize in evaporator 11. If the coolant temperature at the inlet of evaporator 11 is too high, or the low-temperature end of the refrigerant is too high, further compression by compressor 12 will further increase the high-temperature end of the refrigerant, potentially reaching the upper limit of compressor 12's discharge temperature, thus limiting compressor 12's operation or preventing it from functioning properly, consequently causing heat pump circuit 10 to malfunction. Conversely, if the ambient temperature is too low, or the coolant temperature at the inlet of evaporator 11 is too low (e.g., below -30°C), the refrigerant cannot vaporize in evaporator 11, causing heat pump circuit 10 to malfunction.

[0058] This application provides an electric vehicle thermal management system. Firstly, this embodiment utilizes the waste heat generated by the heat source component 23 to provide heat for the vaporization of the refrigerant in the evaporator 11. The refrigerant temperature is increased by compressing it with the compressor 12. Heat exchange occurs between the refrigerant and the coolant in the heating component circuit in the condenser 13, forming a heating cycle in the heat pump circuit 10, with a heating efficiency higher than that of electric heating. Secondly, if the heat pump circuit 10 cannot operate normally due to excessively low ambient or water temperatures, this embodiment connects a heat storage bypass 30 in parallel with the waste heat circuit 20. Part of the heat released by the heat source component 23 during operation can be transferred to the evaporator 11 via the second waste heat pipe 22, and the other part can be transferred via the heat storage bypass 30. The heat storage device 31 in the heat pump releases heat to the evaporator 11. The coolant can absorb some heat through the heat storage device 31, increasing the coolant temperature at the inlet of the evaporator 11, and thus increasing the temperature of the refrigerant in the evaporator 11, reaching the minimum temperature requirement for the heat pump to operate, allowing the heat pump to work normally. Thirdly, the heat source component 23 exchanges heat with the refrigerant in the evaporator 11 through the coolant, and releases heat from the refrigerant in the condenser 13 through the heat pump circuit 10, which is configured to heat the heating component 42 of the electric vehicle, recovering waste heat and saving energy. Compared with the prior art, the embodiment of this application does not require the activation of the WPTC electric heating device, and the heating efficiency is higher than that of WPTC, which can reduce the reduction of the electric vehicle's driving range, thereby saving energy consumption of the electric vehicle.

[0059] The heat source component 23 is a component in an electric vehicle that can release heat. In this embodiment, the heat source component 23 can be a motor or a power battery.

[0060] The type of heat storage device 31 is not limited. In this embodiment, the heat storage device 31 is a phase change heat storage device, which is a device that uses the latent heat released or absorbed during the phase change of a substance to store and release heat.

[0061] Referring to Figure 1, in this embodiment of the application, the second waste heat pipeline 22 includes, in sequence along the flow direction of the coolant, an input main section 222, a branch section 221, and an output main section 223. The input main section 222 is connected to the waste heat output end of the heat source component 23, and the output main section 223 is connected to the coolant inlet end of the evaporator 11.

[0062] In this embodiment of the application, a temperature sensor can be installed in the second waste heat pipe 22. The specific arrangement of the temperature sensor is as follows:

[0063] Referring to Figures 1-6, in the first embodiment of this application, the input trunk section 222 of the second waste heat pipeline 22 is equipped with a first temperature sensor 27, configured to detect the coolant temperature at the waste heat output end of the heat source component 23. Based on the coolant temperature at the waste heat output end of the heat source component 23 detected by the first temperature sensor 27, the electric vehicle thermal management system controls the flow direction of the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11. Specifically:

[0064] If the temperature of the coolant at the waste heat output end of the heat source component 23 detected by the first temperature sensor 27 is greater than the maximum value of the preset temperature of the coolant at the liquid inlet end of the evaporator 11, then the coolant between the waste heat output end of the heat source component 23 and the liquid inlet end of the evaporator 11 is controlled to flow to the evaporator 11 through the heat storage bypass 30, and does not pass through the branch section 221 of the second waste heat pipeline 22.

[0065] If the coolant temperature at the waste heat output end of the heat source component 23 falls within the preset coolant temperature range at the inlet end of the evaporator 11, the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11 is controlled to flow to the evaporator 11 through the branch section 221 of the second waste heat pipeline 22, without passing through the heat storage bypass 30, and the heat pump circuit 10 is controlled to work.

[0066] If the coolant temperature at the waste heat output end of the heat source component 23 is less than the minimum preset coolant temperature at the liquid inlet end of the evaporator 11, then the coolant between the waste heat output end of the heat source component 23 and the liquid inlet end of the evaporator 11 flows to the evaporator 11 via the heat storage bypass 30 and the branch section 221 of the second waste heat pipeline 22.

[0067] Referring to Figures 1-6, in the second embodiment of this application, the output trunk section 223 of the second waste heat pipeline 22 is equipped with a second temperature sensor 28, configured to detect the coolant temperature at the inlet of the evaporator 11. The electric vehicle thermal management system controls whether the heat pump circuit 10 operates based on the coolant temperature at the inlet of the evaporator 11 detected by the second temperature sensor 28. Specifically:

[0068] If the coolant between the waste heat output end of the heat source component 23 and the liquid inlet end of the evaporator 11 flows to the evaporator 11 through the heat storage bypass 30 or the branch section 221 of the second waste heat pipeline 22, and the temperature of the coolant at the liquid inlet end of the evaporator 11 falls within the preset temperature range of the coolant at the liquid inlet end of the evaporator 11, then the heat pump circuit 10 is controlled to work; otherwise, the heat pump circuit 10 is controlled not to work.

[0069] If the coolant between the waste heat output end of the heat source component 23 and the liquid inlet end of the evaporator 11 flows to the evaporator 11 via the heat storage bypass 30 and the branch section 221 of the second waste heat pipeline 22, and the opening degree of the control valve connecting the heat storage bypass 30 is the first preset opening degree, and the opening degree of the control valve connecting the branch section 221 of the second waste heat pipeline 22 is the second preset opening degree, if the coolant temperature at the liquid inlet end of the evaporator 11 falls within the preset temperature range of the coolant at the liquid inlet end of the evaporator 11, then the heat pump circuit 10 is controlled to work and the first current opening degree and the second current opening degree are maintained; otherwise, the heat pump circuit 10 is controlled not to work and the first current opening degree and the second current opening degree are adjusted.

[0070] Referring to Figures 1-6, in the third embodiment of this application, the input main section 222 of the second waste heat pipeline 22 is equipped with a first temperature sensor 27, configured to detect the coolant temperature at the waste heat output end of the heat source component 23; the output main section 223 of the second waste heat pipeline 22 is equipped with a second temperature sensor 28, configured to detect the coolant temperature at the inlet end of the evaporator 11. Based on the coolant temperature at the waste heat output end of the heat source component 23 detected by the first temperature sensor 27, the electric vehicle thermal management system controls the flow direction of the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11; based on the coolant temperature at the inlet end of the evaporator 11 detected by the second temperature sensor 28, it controls whether the heat pump circuit 10 is working and adjusts the opening of the control valve connecting the heat storage bypass 30 and the control valve connecting the branch section 221 of the second waste heat pipeline 22, so that the coolant temperature at the inlet end of the evaporator 11 falls within the preset temperature range of the coolant at the inlet end of the evaporator 11. Specifically as follows:

[0071] If the coolant temperature at the waste heat output end of the heat source component 23 detected by the first temperature sensor 27 is greater than the maximum value of the preset coolant temperature at the inlet end of the evaporator 11, then the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11 is controlled to flow to the evaporator 11 through the heat storage bypass 30, and after bypassing the branch section 221 of the second waste heat pipeline 22, the coolant temperature at the inlet end of the evaporator 11 is further detected by the second temperature sensor 28. It is then determined whether the coolant temperature at the inlet end of the evaporator 11 detected by the second temperature sensor 28 falls within the range of the preset coolant temperature at the inlet end of the evaporator 11. If so, the heat pump circuit 10 is controlled to work.

[0072] If the coolant temperature at the waste heat output end of the heat source component 23 detected by the first temperature sensor 27 is less than the minimum preset coolant temperature at the inlet end of the evaporator 11, then after controlling the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11 to flow to the evaporator 11 via the heat storage bypass 30 and the branch section 221 of the second waste heat pipeline 22, and controlling the opening degree of the control valve connected to the heat storage bypass 30 to the first preset opening degree and the opening degree of the control valve connected to the branch section 221 of the second waste heat pipeline 22 to the second preset opening degree, the coolant temperature at the inlet end of the evaporator 11 is further detected by the second temperature sensor 28 to determine whether the coolant temperature at the inlet end of the evaporator 11 falls within the range of the preset coolant temperature at the inlet end of the evaporator 11. If yes, the first current opening degree and the second current opening degree are maintained, and the heat pump circuit 10 is controlled to work; if no, the first current opening degree and the second current opening degree are adjusted.

[0073] In this embodiment of the application, in addition to setting a second temperature sensor 28 in the output trunk section 223 of the second waste heat pipeline 22, the coolant temperature at the liquid inlet of the evaporator 11 can also be indirectly obtained based on an ambient temperature sensor or by setting a temperature sensor at the refrigerant outlet of the evaporator 11 or other methods. This application does not limit this.

[0074] In this embodiment, the second waste heat pipeline 22 includes an input main section 222, a branch section 221, and an output main section 223 connected sequentially along the flow direction of the coolant. A heat storage bypass 30 is connected in parallel to the branch section 221 of the second waste heat pipeline 22. The heat storage bypass 30 may or may not be connected to the input main section 222; the branch section 221 may or may not be connected to the input main section 222. This can be achieved by setting a control valve, as detailed below:

[0075] Referring to Figure 3, in one embodiment of this application, the second waste heat pipeline 22 is equipped with a three-way valve 24. The three-way valve 24 has an inlet end 241, a first outlet end 242, and a second outlet end 243. The inlet end 241 is connected to the waste heat output end of the heat source component 23, the first outlet end 242 is connected to the liquid inlet end of the heat storage tank 31, and the second outlet end 243 is connected to the coolant inlet end of the evaporator 11. Specifically, the second waste heat pipeline 22 includes an input main section 222, a branch section 221, and an output main section 223 connected in sequence. The three-way valve 24 is located at the connection between the input main section 222 and the branch section 221. The inlet end 241 is connected to one end of the input main section 222, and the first outlet end 242 is connected to one end of the branch section 221.

[0076] It should be noted that the working principle of the electric vehicle thermal management system provided in this application embodiment is as follows:

[0077] Referring to Figure 3, if the coolant temperature at the waste heat output end of the heat source component 23 is greater than the maximum value of the preset coolant temperature at the inlet end of the evaporator 11, the inlet end 241 and the first outlet end 242 of the three-way valve 24 are opened, thereby connecting the first waste heat pipeline 21 and the heat storage bypass 30. The coolant flows to the evaporator 11 through the heat storage bypass 30, so that part of the heat released by the heat source component 23 is stored in the heat storage tank 31, thereby reducing the coolant temperature at the inlet end of the evaporator 11. If the coolant temperature at the inlet end of the evaporator 11 is greater than the maximum value of the preset coolant temperature at the inlet end of the evaporator 11, the heat pump circuit 10 cannot work normally due to the excessively high exhaust temperature. Referring to Figure 4, if the coolant temperature at the inlet end of the evaporator 11 falls within the range of the preset coolant temperature at the inlet end of the evaporator 11, the heat pump circuit 10 is turned on. That is, the coolant temperature at the waste heat output end of the heat source component 23 exceeds the operating range of the heat pump circuit 10. When the temperature reaches the upper limit, the coolant that absorbs heat from the heat source component 23 first passes through the heat storage tank 31 for heat storage and storage. After the coolant is cooled down, it flows to the evaporator 11. Therefore, when the coolant temperature at the waste heat output end of the heat source component 23 exceeds the upper limit of the operating temperature of the heat pump circuit 10, the inlet end 241 and the first outlet end 242 of the three-way valve 24 are connected to the first waste heat pipeline 21 and the heat storage bypass 30. This lowers the coolant temperature at the inlet end of the evaporator 11 to within the preset temperature range of the coolant at the inlet end of the evaporator 11, allowing the heat pump circuit 10 to operate. This widens the upper limit of the operating temperature of the heat pump circuit 10. In other words, when the coolant temperature at the waste heat output end of the heat source component 23 is high, the coolant flows to the evaporator 11 through the heat storage bypass 30, ensuring that the coolant temperature entering the evaporator 11 meets the preset temperature of the coolant at the inlet end of the evaporator 11, allowing the heat pump circuit 10 to operate.

[0078] Referring to Figure 5, if the coolant temperature at the waste heat output end of the heat source component 23 falls within the range of the preset coolant temperature at the inlet end of the evaporator, the inlet end 241 and the second outlet end 243 of the three-way valve 24 are opened, thereby connecting the branch section 221 of the first waste heat pipeline 21 and the second waste heat pipeline 22. The coolant that absorbs the heat released by the heat source component 23 flows to the evaporator 11 through the branch section 221 of the second waste heat pipeline 22. At this time, the coolant temperature at the inlet end of the evaporator 11 is within the operating temperature range of the heat pump circuit 10, providing heat for the evaporation of the refrigerant in the evaporator 11; thereby ensuring the heat required for the vaporization of the refrigerant in the evaporator 11 and ensuring the normal operation of the heat pump circuit 10.

[0079] Referring to Figure 6, if the coolant temperature at the waste heat output end of the heat source component 23 is lower than the preset coolant temperature at the evaporator inlet end, then the first outlet end 242 and the second outlet end 243 are both connected to the inlet end 241, thereby connecting the first waste heat pipeline 21 and the heat storage bypass 30, as well as the branch section 221 connecting the first waste heat pipeline 21 and the second waste heat pipeline 22. The coolant flows to the evaporator 11 via the heat storage bypass 30, and also flows to the evaporator 11 via the branch section 221 of the second waste heat pipeline 22, thereby improving the efficiency of the evaporator 11. The coolant temperature at the inlet provides heat for the vaporization of the refrigerant in the evaporator 11, ensuring the normal operation of the heat pump circuit 10. Specifically, when the coolant temperature at the waste heat output end of the heat source component 23 is lower than the lower limit of the operating temperature of the heat pump circuit 10, heat is released by the heat storage device 31 in the heat storage bypass 30 through the connection of the first waste heat pipe 21 and the heat storage bypass 30, as well as the connection of the first waste heat pipe 21 and the second waste heat pipe 22. This increases the coolant temperature at the inlet of the evaporator 11, thereby widening the lower limit of the operating temperature of the heat pump circuit 10. In other words, when the coolant temperature at the waste heat output end of the heat source component 23 is low, the heat pump circuit 10 can operate when the coolant flows to the evaporator 11 through the branch sections 221 of the heat storage bypass 30 and the second waste heat pipe 22, respectively, so that the coolant temperature entering the evaporator 11 meets the preset coolant temperature at the inlet of the evaporator 11. During this process, the coolant flow rate of the heat storage bypass 30 and the coolant flow rate of the second waste heat pipeline 22 are controlled by controlling the opening degree of the first outlet end 242 and the second outlet end 243, thereby controlling the coolant temperature at the inlet end of the evaporator 11. Specifically, if the coolant temperature at the waste heat output end of the heat source component 23 is lower than the preset coolant temperature at the inlet end of the evaporator 11, the first outlet end 242 and the second outlet end 243 are both connected to the inlet end 241, and the first outlet end 242 is controlled at the first preset opening degree and the second outlet end 243 is controlled at the second preset opening degree. Optionally, if the coolant temperature at the inlet end of the evaporator 11 falls within the range of the preset coolant temperature at the inlet end of the evaporator 11, the first current opening degree and the second current opening degree are maintained and the heat pump circuit 10 is controlled to work; otherwise, the first current opening degree and the second current opening degree are adjusted until the coolant temperature at the inlet end of the evaporator 11 falls within the range of the preset coolant temperature at the inlet end of the evaporator 11.

[0080] Therefore, the electric vehicle thermal management system provided in this application embodiment is equipped with a three-way valve 24. Based on the coolant temperature at the waste heat output end of the heat source component 23, the flow direction of the coolant between the waste heat output end of the heat source component 23 and the evaporator 11 is controlled. That is, if the coolant temperature at the inlet end of the evaporator 11 is too high, the heat pump circuit 10 cannot work normally. The coolant is controlled to flow to the evaporator 11 through the heat storage bypass 30, so that part of the heat released by the heat source component 23 is stored in the heat storage tank 31, thereby reducing the coolant temperature at the inlet end of the evaporator 11, which is beneficial to the heat pump circuit 10. The system enters normal operating condition. If the coolant temperature at the inlet of the evaporator 11 is too low, the coolant is controlled to flow to the evaporator 11 via the heat storage bypass 30 and via the branch section 221 of the second waste heat pipeline 22. The opening of the first outlet end 242 and the second outlet end 243 of the three-way valve 24 is also controlled. The evaporator 11 absorbs heat from the heat storage tank 31 and the waste heat circuit 20, thereby increasing the coolant temperature at the inlet of the evaporator 11 and providing heat for the vaporization of the refrigerant in the evaporator 11. In summary, the technical solution of this application embodiment broadens the operating temperature range of the heat pump circuit 10.

[0081] In this embodiment of the application, the electric vehicle thermal management system also includes a controller, and the three-way valve 24 is electrically connected to the controller.

[0082] In this embodiment, a temperature sensor is installed in the second waste heat pipeline 22 on the basis of the three-way valve 24. The arrangement of the temperature sensor and the controller controlling the three-way valve 24 based on the temperature value detected by the temperature sensor are as follows:

[0083] In this embodiment, in a first scenario, a first temperature sensor 27 is provided in the input trunk section 222 of the second waste heat pipeline 22, located between the waste heat output end of the heat source component 23 and the inlet end 241 of the three-way valve 24. This sensor is configured to detect the coolant temperature at the waste heat output end of the heat source component 23. The first temperature sensor 27 is electrically connected to a controller, which is configured to control the opening and closing of the first outlet end 242 and the second outlet end 243 of the three-way valve 24 based on the coolant temperature detected by the first temperature sensor 27 at the waste heat output end of the heat source component 23. This configuration enables the automatic opening and closing of the first outlet end 242 and the second outlet end 243 of the three-way valve 24.

[0084] In this embodiment, in the second scenario, a second temperature sensor 28 is provided on the output trunk section 223 of the second waste heat pipeline 22, located between the second outlet end 243 of the three-way valve 24 and the coolant inlet end of the evaporator 11. This sensor is configured to detect the coolant temperature at the inlet end of the evaporator 11. The second temperature sensor 28 is electrically connected to a controller, which is configured to control the opening degree of the first outlet end 242 and the second outlet end 243 of the three-way valve 24 based on the coolant temperature detected by the second temperature sensor 28 at the inlet end of the evaporator 11. This configuration enables automatic adjustment of the opening degree of the first outlet end 242 and the second outlet end 243 of the three-way valve 24.

[0085] In this embodiment, the third scenario can be a combination of the first and second scenarios, which will not be elaborated further here. This configuration enables the automatic opening and closing of the first outlet end 242 and the second outlet end 243 of the three-way valve 24, as well as the automatic adjustment of the opening degree.

[0086] Referring to Figure 2, in another embodiment of this application, the second waste heat pipeline 22 is equipped with a first valve 25, which is located between the waste heat output end of the heat source component 23 and the coolant inlet end of the evaporator 11; the heat storage bypass 30 is equipped with a second valve 26, which is located between the waste heat output end of the heat source component 23 and the coolant inlet end of the heat storage tank 31. The opening degree of the first valve 25 and the second valve 26 is adjustable. It should be noted that the combination of the first valve 25 and the second valve 26 has the same function as the three-way valve 24, which will not be described again here.

[0087] In this embodiment of the application, the electric vehicle thermal management system further includes a controller, and the first valve 25 and the second valve 26 are both electrically connected to the controller.

[0088] In this embodiment, based on the first valve 25 and the second valve 26, a temperature sensor is installed in the second waste heat pipeline 22. The arrangement of the temperature sensor and the controller controlling the first valve 25 and the second valve 26 based on the temperature value detected by the temperature sensor are as follows:

[0089] In the first embodiment, the input trunk section 222 of the second waste heat pipeline 22 is provided with a first temperature sensor 27, located between the waste heat output end of the heat source component 23 and the first valve 25, configured to detect the coolant temperature at the waste heat output end of the heat source component 23. The first temperature sensor 27 is electrically connected to a controller, which is configured to control the opening and closing of the first valve 25 and the second valve 26 based on the coolant temperature at the waste heat output end of the heat source component 23 detected by the first temperature sensor 27.

[0090] In the second embodiment, the output trunk section 223 of the second waste heat pipeline 22 is equipped with a second temperature sensor 28, located between the outlet end of the first valve 25 and the inlet end of the coolant of the evaporator 11, configured to detect the coolant temperature at the inlet end of the evaporator 11. The second temperature sensor 28 is electrically connected to a controller, which is configured to control the opening degree of the first valve 25 and the second valve 26 based on the coolant temperature detected at the inlet end of the evaporator 11 by the second temperature sensor 28.

[0091] The third embodiment can be a combination of the first and second embodiments, which will not be described in detail here.

[0092] Referring to Figure 1, in this embodiment of the electric vehicle thermal management system, a heating demand loop 40 is further included. The two ends of the heating demand loop 40 are connected to the condenser 13, configured to absorb the heat released by the condenser 13. The heating demand loop 40 is configured to heat the component 42 to be heated. With this configuration, the heat generated by the heat source component 23 of the electric vehicle provides heat to the evaporator 11 of the heat pump circuit 10, enabling the refrigerant to vaporize in the evaporator 11. The refrigerant is then compressed into a high-temperature, high-pressure gas by the compressor 12. This high-temperature, high-pressure gas is then cooled by the condenser 13, releasing heat. The condenser 13 is connected to the heating demand loop 40, and the refrigerant in the condenser 13 releases heat into the coolant of the heating demand loop 40, configured to heat the component 42 to be heated. Compared with the prior art, this application does not require a WPTC heat source, has higher heating efficiency than WPTC, and can reduce the reduction in the electric vehicle's driving range, thereby saving energy consumption.

[0093] Referring to Figure 1, in this embodiment of the application, the heating demand circuit 40 is provided with a first connector 41 and a second connector 43. The first connector 41 is configured to connect to the liquid outlet of the component to be heated 42; the second connector 43 is configured to connect to the liquid inlet of the component to be heated 42. This configuration allows for the connection of different components to be heated 42 based on actual needs, thereby improving the practicality of the heating demand circuit 40.

[0094] In this embodiment of the application, the component 42 to be heated may be a passenger compartment or a battery.

[0095] It should be noted that in extremely cold environments, it is difficult for the battery temperature to reach its optimal operating temperature, resulting in a decrease in battery power and capacity. In extreme cold, irreversible damage to battery capacity may even occur. Heating the battery ensures that it operates within a suitable temperature range for discharge.

[0096] It should be noted that heating the passenger cabin is used to improve passenger comfort in cold winter conditions.

[0097] In this embodiment of the application, a phase change heat storage device is provided with a phase change material. A phase change material is a substance that changes its physical state and can provide latent heat while maintaining a constant temperature. The process of changing physical properties is called a phase change process, during which the phase change material absorbs or releases a large amount of latent heat.

[0098] In this embodiment of the application, the melting temperature range of the phase change material is between 0°C and 30°C.

[0099] In this embodiment, the phase change material is an alcohol, paraffin, fatty acid, aromatic hydrocarbon, or polymer.

[0100] In the embodiments of this application, the refrigerant may be one of the refrigerants R290, R134a, and R1234yf, or a mixture of any two or more refrigerants.

[0101] In this embodiment, the coolant may be a mixture of water and ethylene glycol.

[0102] Referring to Figures 3-6 and 7-9, a second aspect of this application provides a control method for an electric vehicle thermal management system, configured as described above. The control method includes the following steps:

[0103] The coolant temperature at the waste heat output end of the heat source component 23 and the preset coolant temperature at the liquid inlet end of the evaporator 11 are obtained.

[0104] If the coolant temperature at the waste heat output end of the heat source component 23 is greater than the maximum value of the preset coolant temperature at the inlet end of the evaporator 11, the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11 is controlled to flow to the evaporator 11 through the heat storage bypass 30, without passing through the branch section 221 of the second waste heat pipeline 22; with this configuration, part of the heat released by the heat source component 23 is stored in the heat storage tank 31, thereby reducing the coolant temperature at the inlet end of the evaporator 11;

[0105] If the coolant temperature at the waste heat output end of the heat source component 23 falls within the preset coolant temperature range at the inlet end of the evaporator 11, the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11 flows to the evaporator 11 via a branch section 221 of the second waste heat pipeline 22, without passing through the heat storage bypass 30, and the heat pump circuit 10 is controlled to operate. With this configuration, the coolant containing the heat released by the heat source component 23 flows to the evaporator 11 via a branch section 221 of the second waste heat pipeline 22, providing heat for the evaporation of the refrigerant in the evaporator 11. This ensures the heat required for the refrigerant to vaporize in the evaporator 11 and guarantees the normal operation of the heat pump circuit 10.

[0106] If the coolant temperature at the waste heat output end of the heat source component 23 is less than the minimum preset coolant temperature at the inlet end of the evaporator 11, then the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11 is controlled to flow to the evaporator 11 via the heat storage bypass 30 and the branch section 221 of the second waste heat pipeline 22, respectively. The opening degree of the control valve connected to the heat storage bypass 30 is controlled to be the first preset opening degree, and the opening degree of the control valve connected to the branch section 221 of the second waste heat pipeline 22 is controlled to be the second preset opening degree. With this setting, the heat in the second waste heat pipeline 22 and the heat stored in the heat storage bypass 30 are both transferred to the evaporator 11, increasing the coolant temperature at the inlet end of the evaporator 11 and providing heat for the vaporization of the refrigerant in the evaporator 11.

[0107] This application provides a control method for an electric vehicle thermal management system. By determining the relationship between the coolant temperature at the waste heat output end of the heat source component 23 and the preset coolant temperature at the inlet end of the evaporator 11, the coolant temperature at the inlet end of the evaporator 11 is controlled by controlling the coolant flow direction between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11.

[0108] Referring to Figure 7, in this embodiment of the application, the control method further includes: obtaining the coolant temperature at the inlet end of the evaporator 11; if the coolant temperature at the waste heat output end of the heat source component 23 is greater than the maximum value of the preset coolant temperature at the inlet end of the evaporator 11, then controlling the coolant between the waste heat output end of the heat source component 23 and the inlet end of the evaporator 11 to flow to the evaporator 11 through the heat storage bypass 30, and without passing through the branch section 221 of the second waste heat pipeline 22, the control method further includes the following steps: determining whether the coolant temperature at the inlet end of the evaporator 11 falls within the preset coolant temperature range at the inlet end of the evaporator 11; if so, controlling the heat pump circuit 10 to work; otherwise, controlling the heat pump circuit 10 not to work.

[0109] If the coolant temperature at the inlet of the evaporator 11 is greater than the maximum preset temperature of the coolant at the inlet of the evaporator 11, the heat pump circuit 10 cannot operate normally due to the excessively high exhaust temperature. If the coolant temperature at the waste heat output end of the heat source component 23 is too high, and only the first waste heat pipe 21 and the second waste heat pipe 22 are connected, the heat pump circuit 10 cannot operate normally. In this embodiment, the first waste heat pipe 21 and the heat storage bypass 30 are connected, so that the coolant flows to the inlet of the evaporator 11 through the heat storage bypass 30. This allows some of the heat released by the heat source component 23 to be stored in the heat storage tank 31, thereby reducing the temperature of the coolant entering the evaporator 11 and facilitating the normal operation of the heat pump circuit 10.

[0110] Referring to Figure 9, in this embodiment of the application, the control method further includes: obtaining the coolant temperature at the inlet of the evaporator 11; if the coolant temperature at the waste heat output end of the heat source component 23 is less than the minimum value of the preset coolant temperature at the inlet of the evaporator 11, then controlling the coolant between the waste heat output end of the heat source component 23 and the inlet of the evaporator 11 to flow to the evaporator 11 via the heat storage bypass 30 and the branch section 221 of the second waste heat pipeline 22, and controlling the opening degree of the control valve connected to the heat storage bypass 30 to the first preset opening degree and the opening degree of the control valve connected to the branch section 221 of the second waste heat pipeline 22 to the second preset opening degree, the control method further includes the following steps: determining whether the coolant temperature at the inlet of the evaporator 11 falls within the range of the preset coolant temperature at the inlet of the evaporator 11; if yes, maintaining the first current opening degree and the second current opening degree, and controlling the heat pump circuit 10 to work; if no, adjusting the first current opening degree and adjusting the second current opening degree.

[0111] If the coolant temperature at the waste heat output end of the heat source component 23 is too low, only the first waste heat pipe 21 and the second waste heat pipe 22 are connected, and the heat pump circuit 10 cannot work normally. In this embodiment, by controlling the connection between the first waste heat pipe 21 and the heat storage bypass 30 and controlling the connection between the branch sections 221 of the first waste heat pipe 21 and the second waste heat pipe 22, and by adjusting the first current opening degree and adjusting the second current opening degree, the coolant flow rate of the heat storage bypass 30 and the coolant flow rate of the second waste heat pipe 22 are controlled, thereby controlling the coolant temperature at the liquid inlet of the evaporator 11 and providing heat for the vaporization of the refrigerant in the evaporator 11.

[0112] In one specific embodiment of this application, the control valve is a three-way valve 24. If the coolant temperature at the waste heat output end of the heat source component 23 is less than the minimum preset coolant temperature at the inlet end of the evaporator 11, then the first waste heat pipeline 21 and the heat storage bypass 30 are connected, and part of the coolant flows to the inlet end of the evaporator 11 through the heat storage bypass 30, and the opening degree of the first outlet end 242 is the first preset opening degree; the first waste heat pipeline 21 and the second waste heat pipeline 22 are connected, and part of the coolant flows to the inlet end of the evaporator 11 through the branch section 221 of the second waste heat pipeline 22, and the opening degree of the second outlet end 243 is the second preset opening degree.

[0113] Determine whether the coolant temperature at the inlet of the evaporator 11 falls within the preset coolant temperature range at the inlet of the evaporator 11. If yes, maintain the first current opening degree and the second current opening degree, and control the heat pump circuit 10 to operate; if no, adjust the first current opening degree and the second current opening degree. After adjusting the first current opening degree and the second current opening degree, continue to determine whether the coolant temperature at the inlet of the evaporator 11 falls within the preset coolant temperature range at the inlet of the evaporator 11.

[0114] In this embodiment of the application, the preset temperature range of the coolant at the liquid inlet of the evaporator 11 is [-30℃, 25℃].

[0115] It should be noted that, since the heat pump circuit 10 has a suitable operating temperature range, when the temperature of the coolant entering the evaporator 11 is too high, the exhaust temperature of the compressor 12 will be high, and the heat inside the compressor 12 cannot be fully and timely removed, which can easily lead to the compressor 12 burning out, and consequently, the heat pump circuit 10 will not work properly. When the temperature of the coolant entering the evaporator 11 is too low, the refrigerant cannot vaporize in the evaporator 11, causing the heat pump circuit 10 to malfunction. Therefore, the control method of the electric vehicle thermal management system provided in this application ensures the normal operation of the heat pump circuit 10 by limiting the preset temperature of the coolant at the inlet of the evaporator 11.

[0116] In this embodiment, the preset temperature range of the coolant at the liquid inlet of the evaporator 11 is related to the type of refrigerant. If the refrigerant is a low-temperature refrigerant, such as R290, the preset temperature range of the coolant at the liquid inlet of the evaporator 11 is [-30℃, 25℃]; if the refrigerant is a non-low-temperature refrigerant, such as R134a or R1234yf, the preset temperature range of the coolant at the liquid inlet of the evaporator 11 is [-10℃, 25℃].

[0117] While this application discloses the above information, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application shall be determined by the scope defined in the claims. Industrial applicability

[0118] The electric vehicle thermal management system and control method provided in this application embodiment can ensure that the heat pump system can work normally when the ambient temperature or water source temperature is too low, while saving energy consumption of the electric vehicle, providing the necessary conditions for the safe and stable operation of the electric vehicle, and has significant economic benefits.

Claims

1. A thermal management system for electric vehicles, characterized in that, include: The heat pump circuit (10) is provided with an evaporator (11), a compressor (12), a condenser (13) and a throttle valve (14) in sequence along the flow direction of the refrigerant; The waste heat circuit (20) is provided sequentially along the flow direction of the coolant, including a first waste heat pipe (21), a heat source component (23), a second waste heat pipe (22), and the evaporator (11). The first waste heat pipe (21) and the second waste heat pipe (22) are configured to transfer the heat released by the heat source component (23) during operation to the evaporator (11); and, A heat storage bypass (30) is connected in parallel to a branch section (221) of the second waste heat pipeline (22); the heat storage bypass (30) is provided with a heat storage device (31), which is configured to store the heat released by the heat source component (23) and transfer the stored heat to the evaporator (11).

2. The electric vehicle thermal management system according to claim 1, characterized in that, The input trunk section (222) of the second waste heat pipeline (22) is equipped with a first temperature sensor (27), which is configured to detect the coolant temperature at the waste heat output end of the heat source component (23); And / or, the output trunk section (223) of the second waste heat pipeline (22) is provided with a second temperature sensor (28) configured to detect the coolant temperature at the inlet end of the evaporator (11).

3. The electric vehicle thermal management system according to claim 1, characterized in that, The second waste heat pipeline (22) is equipped with a three-way valve (24), which has an inlet end (241), a first outlet end (242) and a second outlet end (243). The inlet end (241) is connected to the waste heat output end of the heat source component (23), the first outlet end (242) is connected to the liquid inlet end of the heat storage tank (31), and the second outlet end (243) is connected to the liquid inlet end of the coolant of the evaporator (11).

4. The electric vehicle thermal management system according to claim 3, characterized in that, The electric vehicle thermal management system also includes a controller, and the three-way valve (24) is electrically connected to the controller; The input trunk section (222) of the second waste heat pipeline (22) is equipped with a first temperature sensor (27), which is located between the waste heat output end of the heat source component (23) and the inlet end (241) of the three-way valve (24). It is configured to detect the coolant temperature at the waste heat output end of the heat source component (23). The first temperature sensor (27) is electrically connected to the controller. The controller is configured to control the opening and closing of the first outlet end (242) and the second outlet end (243) of the three-way valve (24) based on the coolant temperature at the waste heat output end of the heat source component (23) detected by the first temperature sensor (27). And / or, the output trunk section (223) of the second waste heat pipeline (22) is provided with a second temperature sensor (28), located between the second outlet end (243) of the three-way valve (24) and the inlet end of the coolant of the evaporator (11), configured to detect the coolant temperature at the inlet end of the evaporator (11), the second temperature sensor (28) is electrically connected to the controller, the controller is configured to: based on the coolant temperature at the inlet end of the evaporator (11) detected by the second temperature sensor (28), control the opening degree of the first outlet end (242) and the second outlet end (243) of the three-way valve (24).

5. The electric vehicle thermal management system according to claim 1, characterized in that, The branch section (221) of the second waste heat pipeline (22) is provided with a first valve (25), which is located between the waste heat output end of the heat source component (23) and the liquid inlet end of the evaporator (11); the heat storage bypass (30) is provided with a second valve (26), which is located between the waste heat output end of the heat source component (23) and the liquid inlet end of the heat storage device (31).

6. The electric vehicle thermal management system according to claim 5, characterized in that, The electric vehicle thermal management system also includes a controller, and the first valve (25) and the second valve (26) are both electrically connected to the controller; The input trunk section (222) of the second waste heat pipeline (22) is equipped with a first temperature sensor (27), located between the waste heat output end of the heat source component (23) and the first valve (25), configured to detect the coolant temperature at the waste heat output end of the heat source component (23). The first temperature sensor (27) is electrically connected to the controller, which is configured to: control the opening and closing of the first valve (25) and the second valve (26) based on the coolant temperature at the waste heat output end of the heat source component (23) detected by the first temperature sensor (27); and / Or, the output trunk section (223) of the second waste heat pipeline (22) is provided with a second temperature sensor (28), located between the outlet end of the first valve (25) and the inlet end of the coolant of the evaporator (11), configured to detect the coolant temperature at the inlet end of the evaporator (11), the second temperature sensor (28) is electrically connected to the controller, the controller is configured to: control the opening degree of the first valve (25) and the second valve (26) based on the coolant temperature at the inlet end of the evaporator (11) detected by the second temperature sensor (28).

7. The electric vehicle thermal management system according to any one of claims 1-6, characterized in that, The electric vehicle thermal management system further includes a heating demand loop (40), the two ends of which are connected to the condenser (13) and configured to absorb the heat released by the condenser (13). The heating demand loop (40) is configured to heat the component (42) to be heated.

8. The electric vehicle thermal management system according to claim 7, characterized in that, The heating demand circuit (40) is provided with a first connector (41) and a second connector (43). The first connector (41) is configured to connect to the liquid outlet of the component to be heated (42); the second connector (43) is configured to connect to the liquid inlet of the component to be heated (42).

9. The electric vehicle thermal management system according to claim 7, characterized in that, The component to be heated (42) is the crew compartment or the battery.

10. The electric vehicle thermal management system according to any one of claims 1-6, characterized in that, The heat storage device (31) is a phase change heat storage device, and the phase change heat storage device is provided with a phase change material; And / or, the heat source component (23) is a motor or a power battery.

11. The electric vehicle thermal management system according to claim 10, characterized in that, The melting temperature range of the phase change material is between 0℃ and 30℃. And / or, the phase change material is an alcohol, paraffin, fatty acid, aromatic hydrocarbon or polymer material.

12. A control method for an electric vehicle thermal management system, characterized in that, The control method shall be configured as the electric vehicle thermal management system according to any one of claims 1-11, and shall include the following steps: Obtain the coolant temperature at the waste heat output end of the heat source component (23) and the preset coolant temperature at the inlet end of the evaporator (11); If the coolant temperature at the waste heat output end of the heat source component (23) is greater than the maximum value of the preset coolant temperature at the liquid inlet end of the evaporator (11), then the coolant between the waste heat output end of the heat source component (23) and the liquid inlet end of the evaporator (11) is controlled to flow to the evaporator (11) through the heat storage bypass (30), and does not pass through the branch section (221) of the second waste heat pipeline (22); If the temperature of the coolant at the waste heat output end of the heat source component (23) falls within the preset temperature range of the coolant at the liquid inlet end of the evaporator (11), the coolant between the waste heat output end of the heat source component (23) and the liquid inlet end of the evaporator (11) is controlled to flow to the evaporator (11) through the branch section (221) of the second waste heat pipeline (22) without passing through the heat storage bypass (30), and the heat pump circuit (10) is controlled to work. If the coolant temperature at the waste heat output end of the heat source component (23) is less than the minimum preset temperature of the coolant at the inlet end of the evaporator (11), the coolant between the waste heat output end of the heat source component (23) and the inlet end of the evaporator (11) is controlled to flow to the evaporator (11) through the heat storage bypass (30) and the branch section (221) of the second waste heat pipeline (22), respectively. The opening degree of the control valve connected to the heat storage bypass (30) is controlled to be the first preset opening degree, and the opening degree of the control valve connected to the branch section (221) of the second waste heat pipeline (22) is controlled to be the second preset opening degree.

13. The control method for the electric vehicle thermal management system according to claim 12, characterized in that, The control method further includes: obtaining the coolant temperature at the inlet end of the evaporator (11); If the coolant temperature at the waste heat output end of the heat source component (23) is greater than the maximum value of the preset coolant temperature at the inlet end of the evaporator (11), then the coolant between the waste heat output end of the heat source component (23) and the inlet end of the evaporator (11) flows through the heat storage bypass (30) to the evaporator (11) without passing through the branch section (221) of the second waste heat pipeline (22), the control method further includes the following steps: Determine whether the temperature of the coolant at the inlet of the evaporator (11) falls within the preset temperature range of the coolant at the inlet of the evaporator (11). If so, control the heat pump circuit (10) to work; otherwise, control the heat pump circuit (10) to not work.

14. The control method for the electric vehicle thermal management system according to claim 12, characterized in that, The control method further includes: obtaining the coolant temperature at the inlet end of the evaporator (11); If the temperature of the coolant at the waste heat output end of the heat source component (23) is less than the minimum value of the preset temperature of the coolant at the inlet end of the evaporator (11), then the coolant between the waste heat output end of the heat source component (23) and the inlet end of the evaporator (11) flows to the evaporator (11) through the heat storage bypass (30) and the branch section (221) of the second waste heat pipeline (22), respectively, and the opening degree of the control valve connected to the heat storage bypass (30) is controlled to be a first preset opening degree and the opening degree of the control valve connected to the branch section (221) of the second waste heat pipeline (22) is controlled to be a second preset opening degree, the control method further includes the following steps: Determine whether the temperature of the coolant at the inlet of the evaporator (11) falls within the range of the preset temperature of the coolant at the inlet of the evaporator (11). If yes, maintain the first current opening degree and the second current opening degree, and control the heat pump circuit (10) to work; if no, adjust the first current opening degree and adjust the second current opening degree.

15. The control method for the electric vehicle thermal management system according to claim 12, characterized in that, The preset temperature range of the coolant at the inlet of the evaporator (11) is [-30℃, 25℃].

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