Finished battery electric vehicle thermal management system based on shell-and-tube phase change heat accumulator and control method of finished battery electric vehicle thermal management system

Abstract

The invention discloses a whole-vehicle thermal management system of a pure electric vehicle based on a shell-and-tube phase change heat accumulator and a control method of the whole-vehicle thermal management system. The whole-vehicle thermal management system comprises a control module, a heat pump air conditioning system, an electric heating and phase change heat storage system, a battery thermal management system and an electric drive cooling system. The control module controls the rotating speed of the compressor and the opening degree of the electronic expansion valve and adjusts refrigerant flow. The control module controls the rotating speed of each water pump and adjusts the cooling liquid flow; the control module controls the fan and the air blower to adjust the air flow, controls the on-off states of the four-way valves, the three-way valves and the one-way valves and adjusts circulation loops of refrigerants and cooling liquid, and therefore energy coupling between different systems and switching of different working modes are achieved. According to the invention, energy coupling and integrated management among the systems are realized, and the thermal management requirement is met with low energy consumption in multiple scenes.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal management of new energy vehicles, and specifically relates to a thermal management system for a pure electric vehicle based on a shell and tube phase change heat accumulator and a control method thereof. Background Art

[0002] The vehicle thermal management system is one of the important components of pure electric vehicles. It absorbs heat from the environment or other heat sources through the air-conditioning system to heat or cool the passenger compartment and batteries, and cool the motor and electronic control. Therefore, the cooling and heating efficiency of the air-conditioning system directly affects the comfort of the passenger compartment and the energy consumption of the vehicle.

[0003] Although the current heat pump air conditioning system reduces energy consumption and improves cooling and heating efficiency, condensation and frost on the radiator outside the vehicle will reduce the heat exchange efficiency with the environment at low temperatures. When the temperature is below -10°C, the heat pump heating efficiency will also decrease. In addition, the heat pump air conditioning, power battery and electric drive thermal management system are relatively independent, and the energy coupling and integrated management between the systems are not achieved, so that a certain amount of waste heat generated by the battery, motor, electronic control and other electronic devices is directly dissipated into the environment.

[0004] Therefore, it is necessary to develop an intelligent thermal management system and its control method, optimize the design of the heat pump air-conditioning system and the waste heat recovery system, so that the passenger compartment, battery, motor and electronic control are all in a suitable environment at different temperatures, meet the thermal management needs with low energy consumption in multiple scenarios, effectively reduce energy consumption and increase mileage. Summary of the invention

[0005] In view of the shortcomings in the prior art, the present invention provides a pure electric vehicle thermal management system based on a shell and tube phase change heat accumulator and a control method thereof, which optimizes the design of the heat pump air-conditioning cooling loop, does not require an additional defrosting device, improves the heating efficiency of the heat pump air-conditioning at low temperatures, and fully recycles and utilizes waste heat through a shell and tube phase change heat accumulator, realizes energy coupling and integrated management among various systems, and meets thermal management requirements with low energy consumption in multiple scenarios.

[0006] The present invention achieves the above technical objectives through the following technical means.

[0007] A thermal management system for a pure electric vehicle based on a shell and tube phase change heat storage device, comprising a heat pump air conditioning system, an electric heating and phase change heat storage system, a battery thermal management system and an electric drive cooling system;

[0008] The heat pump air conditioning system comprises a compressor, a first four-way valve, an indoor heat exchanger, a first electronic expansion valve, an outdoor heat exchanger, a first single-way valve and a gas-liquid separator which are connected in sequence; the first four-way valve is also connected to the gas-liquid separator; the first four-way valve is also connected to the second single-way valve, the first heat exchanger, the third electronic expansion valve, the first electronic expansion valve, the second electronic expansion valve, the second heat exchanger and the first three-way valve in sequence through node A; two ports of the first three-way valve, one of which is connected to a port of the first four-way valve and a port of the first single-way valve respectively through node I, and the other is connected to a port of the second single-way valve and the first heat exchanger respectively through node B;

[0009] The electric heating and phase-change heat storage system comprises a first water pump, a warm air core, a heater, a second four-way valve, a shell and tube phase-change heat storage device and a third single-way valve which are connected in sequence; one port of the third single-way valve is connected to node C and one port of the second three-way valve through node F; one port of the second four-way valve is connected to the first water pump; the node C is also connected to the second four-way valve and the shell and tube phase-change heat storage device;

[0010] The battery thermal management system includes a second water pump, a power battery, a third four-way valve, a second three-way valve and a first heat exchanger which are connected in sequence; the first heat exchanger is connected to the second water pump and the second four-way valve respectively through a node D;

[0011] The electrically driven cooling system includes a third water pump, a motor controller, a drive motor, a third three-way valve, a second heat exchanger, a third four-way valve and an outdoor radiator which are connected in sequence; one port of the third three-way valve is connected to the outdoor radiator and the third water pump respectively through a node G.

[0012] The above technical solution also includes a fan and a blower, wherein the fan is arranged at the outdoor radiator, and the blower is arranged at the indoor heat exchanger; the outdoor heat exchanger and the outdoor radiator are integrated with each other, the outdoor heat exchanger is located on the outside, and the outdoor radiator is located on the inside. When the fan is working, it blows air from the outdoor radiator to the outdoor heat exchanger to take away the system heat.

[0013] In the above technical solution, the heat pump air-conditioning system is connected to the battery thermal management system through the first heat exchanger, the heat pump air-conditioning system is connected to the electric drive cooling system through the second heat exchanger, the battery thermal management system is connected to the electric drive cooling system through the third four-way valve, and the electric heating and phase change heat storage system and the battery thermal management system are connected through the second four-way valve, the third one-way valve and the second three-way valve.

[0014] The above technical solution also includes a control module, which is respectively communicated with the compressor, the first four-way valve, the first electronic expansion valve, the second electronic expansion valve, the third electronic expansion valve, the first single-way valve, the second single-way valve, the first three-way valve, the first water pump, the warm air core, the heater, the second four-way valve, the third single-way valve, the second water pump, the third four-way valve, the second three-way valve, the third water pump, the third three-way valve, the fan and the blower.

[0015] A control method for a thermal management system of a pure electric vehicle, wherein a control module controls the speed of a compressor and the opening of an electronic expansion valve to adjust the flow of a refrigerant; the control module controls the speed of each water pump to adjust the flow of a coolant; the control module controls a fan and a blower to adjust the air flow, controls the on / off state of each four-way valve, three-way valve, and single-way valve, and adjusts the circulation circuit of the refrigerant and the coolant, thereby realizing energy coupling between different systems and switching between different working modes.

[0016] Furthermore, the switching of different working modes is specifically as follows:

[0017] Determine whether the vehicle is in the start-up state. When the vehicle is started, monitor the passenger compartment temperature, battery temperature and electric drive water outlet temperature;

[0018] When the passenger compartment temperature is less than 16°C, further determine whether there is waste heat from the battery and electric drive that can be used. If so, use the heat pump air conditioner and waste heat to heat the passenger compartment. If not, further determine whether the ambient temperature is less than -15°C. If so, use the heat storage device and PTC to assist the heat pump air conditioner to heat the passenger compartment. Otherwise, use the heat storage device to assist the heat pump air conditioner to heat the passenger compartment. When the passenger compartment temperature is greater than 26°C, use the heat pump air conditioner to cool the passenger compartment.

[0019] When the power battery temperature is less than 20°C, further determine whether there is electric drive waste heat that can be used. If so, use the electric drive waste heat to assist the heat pump air conditioner to heat the battery mode. If not, further determine whether the ambient temperature is less than -15°C. If so, use the heat storage device and PTC to assist the heat pump air conditioner to heat the battery mode. Otherwise, use the heat storage device to assist the heat pump to heat the battery mode. When the power battery temperature is greater than 30°C, further determine the passenger compartment temperature. If it is not less than 16°C, further determine whether the ambient temperature is less than 20°C. If so, use the radiator to cool the battery mode. Otherwise, use the heat pump air conditioner to cool the battery mode. If the passenger compartment temperature is less than 16°C, further determine whether the battery's available waste heat is greater than the passenger compartment heating demand. If not, use the battery waste heat to heat the passenger compartment, that is, the heat pump air conditioner to cool the battery mode. Otherwise, further determine whether the phase change heat storage heat is sufficient. If not, use the battery waste heat to heat the passenger compartment and the heat storage heat storage mode. Otherwise, use the battery waste heat to heat the passenger compartment and the radiator to cool the battery mode.

[0020] When the temperature of the electric drive system is less than 60°C, the motor self-insulation mode is started; when the temperature of the electric drive system is not less than 60°C, it is further determined whether the temperature of the passenger compartment is less than 16°C or the temperature of the power battery is less than 20°C, that is, whether the vehicle system needs waste heat. If not, it is further determined whether the ambient temperature is less than 20°C. If so, the radiator cooling electric drive mode is adopted. Otherwise, the heat pump air conditioning cooling electric drive mode is adopted. If waste heat is needed, it is further determined whether the waste heat available for the electric drive is greater than the heating demand of the battery and the passenger compartment. If not, the electric drive waste heat recovery mode is adopted, that is, the heat pump air conditioning cooling electric drive mode. Otherwise, it is further determined whether the heat storage capacity of the phase change heat accumulator is sufficient. If not, the electric drive waste heat heating and phase change heat accumulator heat storage modes are adopted. Otherwise, the electric drive waste heat heating and radiator cooling electric drive modes are adopted.

[0021] When the vehicle is parked or turned off, determine whether the ambient temperature is less than 15°C and whether the vehicle will be restarted in a short time. If not, further determine whether the heat stored in the phase change heat accumulator is sufficient. If sufficient, use the radiator heat dissipation mode. Otherwise, use the phase change heat accumulator heat storage mode. If all are satisfied, further determine whether the residual heat of the electric drive and the battery meets the insulation and heating requirements of the battery and the passenger compartment. If not, use the battery and passenger compartment self-insulation mode. Otherwise, further determine whether the heat stored in the phase change heat accumulator is sufficient. If sufficient, use the battery and passenger compartment self-insulation and radiator heat dissipation mode. Otherwise, use the battery and passenger compartment self-insulation and phase change heat accumulator heat storage mode.

[0022] When the battery starts fast charging, it first determines whether the battery temperature is less than 30°C. If so, the battery self-heating mode is activated. If so, it further determines whether the battery temperature is greater than 40°C. If so, the heat pump air conditioner and radiator are used to cool the battery. Otherwise, the radiator alone is used to cool the battery.

[0023] When the ambient temperature is monitored to be within 0-5°C and the air humidity is greater than 70%, determine whether the heating efficiency of the heat pump decreases under the same working conditions. If the heating efficiency decreases, start the outdoor heat exchanger defrost mode, and use the heat storage and waste heat auxiliary heating mode to keep the battery and passenger compartment in the optimal temperature area. Otherwise, continue the cycle monitoring.

[0024] Furthermore, in a certain mode, the compressor speed, electronic expansion valve opening, and water pump speed are adjusted to optimize the temperature of the passenger compartment and the power battery. Among them, the compressor speed adopts model predictive control, and the electronic expansion valve opening and water pump speed adopt PID control.

[0025] Furthermore, the compressor speed adopts model predictive control, specifically:

[0026] Under different working modes of the vehicle thermal management system, the state quantity and input quantity are selected, and a nonlinear model between the state quantity and control quantity of the air-conditioning system at a certain moment is established. Then, the Taylor series is expanded and only the first-order terms are retained to obtain the approximate linear model of the air-conditioning system. The nonlinear model is subtracted from the approximate linear model and discretized to obtain the discretized state space model of the air-conditioning system:

[0027]

[0028] Among them, x(k+1) represents the state of the air conditioning system at the k+1 reference time, A x is the state matrix, x(k) represents the state quantity at discrete time k, B u is the input matrix, u(k) represents the input at discrete time k, y(k) represents the output at time k, and C is the output matrix;

[0029] The model predictive controller uses the state space model of the air conditioning system to predict the future change trend of the passenger compartment temperature, compares it with the passenger compartment target temperature, and adjusts the compressor speed based on the optimization algorithm;

[0030] When designing a model predictive controller, the following two goals must be met simultaneously: goal one is to get the expected output value closer to the target value, and goal two is to reduce energy consumption;

[0031] The objective function of goal one is:

[0032]

[0033] Among them, y t (k+i) is the passenger compartment temperature predicted by the air conditioning system state space model, w t (k+i) is the target temperature of the passenger compartment, and P represents the prediction time domain;

[0034] The objective function of goal 2 is:

[0035]

[0036] Wherein, Δu(k) is the rate of change of compressor speed, and M represents the control time domain;

[0037] The overall objective function of the model predictive controller is:

[0038] J=J 1 *ω 1 +J 2 *ω 2

[0039] Among them, ω 1 and ω 2 are the weight coefficients of target one and target two respectively;

[0040] By solving the overall objective function, the optimized compressor speed can be obtained to achieve optimal control of the passenger compartment and battery temperature.

[0041] Furthermore, the opening of the electronic expansion valve is controlled by PID. Specifically, the electronic expansion valve adjusts the heat exchange amount of the refrigerant in the heat exchanger by controlling the superheat of the system. Based on PID control, the saturated pressure of the refrigerant at the target superheat is used as the target value, the actual pressure at the outlet of the heat exchanger is used as the actual value, and the opening of the electronic expansion valve is used as the control output.

[0042] Furthermore, the water pump speed is controlled by PID, specifically:

[0043] In the battery coolant circulation system, by establishing a heat generation model and heat exchange calculation for the power battery, the current battery temperature change trend is obtained in real time to obtain the actual battery temperature. The difference between the actual battery temperature and the target temperature is used as the input of the PID control, and the speed of the second water pump is used as the output to regulate the coolant flow, thereby achieving a dynamic balance of the battery temperature.

[0044] In the cooling circulation system of the motor and motor controller, the sensor monitors the actual temperature of the motor water outlet in real time. The controller uses the difference between the target water temperature and the actual water temperature as input, and outputs the third water pump speed to optimize the coolant flow distribution, thereby achieving the optimal balance of energy consumption while meeting the heat dissipation requirements.

[0045] The beneficial effects brought by the present invention are:

[0046] (1) The vehicle thermal management system of the present invention comprises a heat pump air conditioning system, an electric heating and phase change heat storage system, a battery thermal management system and an electric drive cooling system. The heat pump air conditioning system comprises a compressor, a first four-way valve, an indoor heat exchanger, a first electronic expansion valve, an outdoor heat exchanger, a first single-way valve, a gas-liquid separator, a second single-way valve, a first heat exchanger, a second electronic expansion valve, a third electronic expansion valve, a second heat exchanger and a first three-way valve. The electric heating and phase change heat storage system comprises a first water pump, a warm air core, a heater, a second four-way valve, a heat storage device and a third single-way valve. The battery thermal management system comprises a second water pump, a power battery, a third four-way valve and a second three-way valve. The electric drive cooling system comprises a third water pump, a motor controller, a drive motor, a third three-way valve and an outdoor radiator. The connection relationship between the various components in the vehicle thermal management system of the present invention is easy to implement, and the control logic is simple and clear.

[0047] (2) The vehicle thermal management system of the present invention can realize multiple thermal cycle working modes including heat pump air conditioning heating passenger compartment mode, heat pump air conditioning heating battery mode, heater and heat storage device heating passenger compartment and battery mode, battery self-insulation (motor waste heat heating battery or heat storage device heating battery) mode, battery and electric drive waste heat recovery (cooling) mode, outdoor heat exchanger defrosting mode, heat pump air conditioning cooling battery and electric drive mode, heat pump air conditioning cooling passenger compartment mode, heat pump air conditioning strong cooling battery and electric drive mode and battery super cooling mode, etc., to meet different thermal management requirements under all-weather conditions;

[0048] (3) The vehicle thermal management system of the present invention also adds a shell and tube type phase change heat accumulator, which absorbs or releases heat through phase change in its internal phase change material system, thereby absorbing waste heat generated by batteries and motors (cooling batteries and electric drives), heating batteries and heating the passenger compartment, and more efficiently recycling the waste heat of batteries and electric drives to increase mileage; the vehicle thermal management system of the present invention is provided with two heat exchangers and a radiator, which can provide strong cooling for batteries or motors during charging or high-speed driving, allowing batteries and motors to fully dissipate heat and maintain a suitable working environment to ensure the reliability of smooth operation of the vehicle. At the same time, the outdoor radiator and the outdoor heat exchanger are placed in one place to reduce the possibility of frost on the outdoor heat exchanger, facilitate defrosting of the outdoor heat exchanger, and effectively reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic diagram of the structure of a thermal management system for a pure electric vehicle based on a shell and tube phase change heat accumulator according to the present invention;

[0050] Figure 2 yes Figure 1 The control module shown has a logic flow chart for switching operating modes based on the passenger compartment temperature;

[0051] Figure 3 yes Figure 1 The control module shown has a logic flow chart for switching operating modes based on battery temperature;

[0052] Figure 4 yes Figure 1 The control module shown has a working mode switching logic flow chart based on the electric drive water outlet temperature;

[0053] Figure 5 yes Figure 1 The control module shown is a logic flow chart of the utilization of waste heat of the vehicle after parking;

[0054] Figure 6 yes Figure 1 The battery fast charging temperature control logic flow chart of the control module shown;

[0055] Figure 7yes Figure 1 The outdoor heat exchanger defrost control logic flow chart of the control module shown;

[0056] Figure 8 for Figure 1 The system diagram of the vehicle thermal management system in the heat pump air conditioning heating passenger compartment mode in a low temperature environment;

[0057] Fig. 9 for Figure 1 The system diagram of the vehicle thermal management system in the heat pump air conditioning heating battery mode in a low temperature environment is shown;

[0058] Fig.10 for Figure 1 The system diagram of the vehicle thermal management system in the low temperature environment heater and heat storage mode for heating the passenger compartment and battery;

[0059] Fig.11 for Figure 1 The system diagram of the vehicle thermal management system in the battery self-insulation mode in a low temperature environment is shown;

[0060] Fig.12 for Figure 1 The system diagram of the vehicle thermal management system in the waste heat recovery mode of the battery and electric drive in a low temperature environment is shown;

[0061] Fig.13 for Figure 1 The system diagram of the vehicle thermal management system in the outdoor heat exchanger defrosting mode in a low temperature environment is shown;

[0062] Fig.14 for Figure 1 The system diagram of the vehicle thermal management system in medium temperature environment, heat pump air conditioning cooling battery and electric drive mode;

[0063] Fig.15 for Figure 1 The system diagram of the vehicle thermal management system in the heat pump air conditioning cooling passenger compartment mode in a high temperature environment;

[0064] Fig.16 for Figure 1 The vehicle thermal management system shown is in battery super cooling mode during fast charging;

[0065] Fig.17 for Figure 1 The system diagram of the vehicle thermal management system in a high temperature environment with heat pump air conditioning, strong cooling of batteries and electric drive is shown;

[0066] The following are the descriptions of the reference numerals:

[0067] 100-vehicle thermal management system, 101-compressor, 102-first four-way valve, 103-indoor heat exchanger, 104-first electronic expansion valve, 105-outdoor heat exchanger, 106-first single-way valve, 107-gas-liquid separator, 108-second single-way valve, 109-third electronic expansion valve, 110-first three-way valve, 111-second electronic expansion valve, 201-first water pump, 202-heater core, 203-heater, 204-second four-way valve, 205-shell and tube phase change heat accumulator, 206-third single-way valve, 301-second water pump, 302-power battery, 303-third four-way valve, 304-second three-way valve, 305-first heat exchanger, 401-third water pump, 402 -motor controller, 403-drive motor, 404-third three-way valve, 405-second heat exchanger, 406-outdoor radiator, 501-fan, 502-blower, 1011-compressor exhaust port, 1012-compressor suction port, 1021-first port of the first four-way valve, 1022-second port of the first four-way valve, 1023-third port of the first four-way valve, 1024-fourth port of the first four-way valve, 1031-first port of the indoor heat exchanger, 1032-second port of the indoor heat exchanger, 1041-first port of the first electronic expansion valve, 1042-second port of the first electronic expansion valve, 1051-first port of the outdoor heat exchanger, 1052-second port of the outdoor heat exchanger, 1061-first single 1062-first one-way valve second port, 1071-gas-liquid separator outlet, 1072-gas-liquid separator inlet, 1081 second one-way valve first port, 1082-second one-way valve second port, 1091-third electronic expansion valve first port, 1092-third electronic expansion valve second port, 1101-first three-way valve first port, 1102-first three-way valve second port, 1103-first three-way valve third port, 1111-second electronic expansion valve first port, 1112-second electronic expansion valve second port, 2011-first water pump outlet, 2012-first water pump inlet, 2021-heating core first port, 2022-heating core second port, 203 1-first port of heater, 2032-second port of heater, 2041-first port of second four-way valve, 2042-second port of second four-way valve, 2043-third port of second four-way valve, 2044-fourth port of second four-way valve, 2051-first port of shell and tube phase change heat accumulator, 2052-second port of shell and tube phase change heat accumulator, 2061 first port of third single-way valve, 2062-second port of third single-way valve, 3011-water outlet of second water pump, 3012-water inlet of second water pump, 3021-first port of power battery, 3022-second port of power battery, 3031-first port of third four-way valve, 3032-second port of third four-way valve, 3033-third port of third four-way valve,3034-the fourth port of the third four-way valve, 3041-the first port of the second three-way valve, 3042-the second port of the second three-way valve, 3043-the third port of the second three-way valve, 3051-the first port of the first heat exchanger, 3052-the second port of the first heat exchanger, 3053-the third port of the first heat exchanger, 3054-the fourth port of the first heat exchanger, 4011-the water outlet of the third water pump, 4012-the water inlet of the third water pump, 4021-the first port of the motor controller, 4022-the second port of the motor controller port, 4031- first port of driving motor, 4032- second port of driving motor, 4041- first port of third three-way valve, 4042- second port of third three-way valve, 4043- third port of third three-way valve, 4051- first port of second heat exchanger, 4052- second port of second heat exchanger, 4053- third port of second heat exchanger, 4054- fourth port of second heat exchanger, 4061- first port of outdoor radiator, 4062- second port of outdoor radiator, 8000- control module. , DETAILED DESCRIPTION

[0068] The present invention will be further described below with reference to relevant drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0069] Figure 1 It is a structural diagram of the vehicle thermal management system 100 described in the present invention, including a heat pump air conditioning system, an electric heating and phase change heat storage system, a battery thermal management system and an electric drive cooling system. The heat pump air conditioning system includes a compressor 101, a first four-way valve 102, an indoor heat exchanger 103, a first electronic expansion valve 104, an outdoor heat exchanger 105, a first single-way valve 106, a gas-liquid separator 107, a second single-way valve 108, a third electronic expansion valve 109, a first three-way valve 110, a second electronic expansion valve 111, a first heat exchanger 305, and a second heat exchanger 405; the electric heating and phase change heat storage system includes a first water pump 201, a warm air core 202, a heater 203, a second four-way valve 204, a shell and tube phase change heat storage device 205, and a third single-way valve 206; the battery thermal management system includes a second water pump 301, a power battery 302, a third four-way valve 303, and a second three-way valve 304; the electric drive cooling system includes a third water pump 401, a motor controller 402, a drive motor 403, a third three-way valve 404, and an outdoor radiator 406.

[0070] The selection and function of each component of the vehicle thermal management system 100 are described as follows. Among them, the compressor 101 uses a scroll type or other type of electric compressor, and its function is to evaporate and compress the refrigerant into superheated steam and promote it to flow in the refrigerant circulation system. Among them, the first four-way valve 102, the second four-way valve 204, the third four-way valve 303, the first three-way valve 110, the second three-way valve 304 and the third three-way valve 404 can be solenoid valves or valves set to other types, as long as they meet the specific connection mode, they can be reasonably replaced. Among them, the indoor heat exchanger 103, the outdoor heat exchanger 105 and the outdoor radiator 406 are air-side heat exchangers, providing heat exchange between air and refrigerant. When the heat pump air conditioner is cooling, the indoor heat exchanger 103 is an evaporator and the outdoor heat exchanger 105 is a condenser. When the heat pump air conditioner is heating, the indoor heat exchanger 103 is a condenser and the outdoor heat exchanger 105 is an evaporator. Wherein, the first electronic expansion valve 104, the second electronic expansion valve 111 and the third electronic expansion valve 109 can be electromagnetic expansion valves or electric expansion valves, and the temperature accuracy of superheat or subcooling can be achieved by controlling the valve hole opening. Wherein, the first one-way valve 106, the second one-way valve 108 and the third one-way valve 206 can be electromagnetic one-way valves or electric one-way valves, which control the circulation loop of the coolant and the refrigerant. Wherein, the gas-liquid separator 107 is used to separate the liquid refrigerant and the gaseous refrigerant in the refrigerant cycle. Wherein, the water pump type used in the first water pump 201, the second water pump 301 and the third water pump 401 is an electric water pump, which drives the coolant to flow in the coolant circulation system. Wherein, the heater 203 can be a positive temperature coefficient heater or other types of heaters. Wherein, the first heat exchanger 305 and the second heat exchanger 405 are water-side heat exchangers, which provide heat exchange between the coolant and the refrigerant. Among them, the shell and tube phase change heat accumulator 205 can be a solid-liquid phase change, liquid-gas phase change or solid-gas phase change heat accumulator, and can be reasonably replaced as long as it meets the heat storage and heat release requirements of the thermal management system. Among them, the fan 501 can be different types of fans, providing the required air flow for the refrigerant in the outdoor heat exchanger 105 and the coolant in the outdoor radiator 406 to exchange heat with the air respectively. Among them, the blower 502 can be different types of electric blowers, providing the required air flow for the refrigerant in the indoor heat exchanger 103 and the coolant in the warm air core 202 to exchange heat with the air respectively.

[0071] The connecting pipelines between the various components of the vehicle thermal management system 100 are described as follows. The first port 1021 of the first four-way valve is connected to the compressor exhaust port 1011, and the third port 1023 of the first four-way valve is connected to the gas-liquid separator inlet 1072; the compressor intake port 1012 is connected to the gas-liquid separator outlet 1071; the pipeline node I is respectively connected to the fourth port 1024 of the first four-way valve, the first port 1061 of the first single-way valve, and the first port 1101 of the first three-way valve; the pipeline node A is respectively connected to the second port 1022 of the first four-way valve, the first port 1031 of the indoor heat exchanger, and the first port 1081 of the second single-way valve; the pipeline node E is respectively connected to the second port 1032 of the indoor heat exchanger, the first port 1041 of the first electronic expansion valve, and the first port 1111 of the second electronic expansion valve ; The pipeline node H is respectively connected to the first port 1091 of the third electronic expansion valve, the second port 1042 of the first electronic expansion valve and the first port 1051 of the outdoor heat exchanger; the second port 1052 of the outdoor heat exchanger is connected to the second port 1062 of the first one-way valve; the second port 1112 of the second electronic expansion valve is connected to the third port 4053 of the second heat exchanger; the fourth port 4054 of the second heat exchanger is connected to the second port 1102 of the first three-way valve; the pipeline node B is respectively connected to the third port 1103 of the first three-way valve, the second port 1082 of the second one-way valve and the third port 3053 of the first heat exchanger; the fourth port 3054 of the first heat exchanger is connected to the second port 1092 of the third electronic expansion valve; the fourth port 1112 of the second electronic expansion valve is connected to the third port 4053 of the second heat exchanger; the fourth port 4054 of the second heat exchanger is connected to the second port 1102 of the first three-way valve; The first port 2041 of the one-way valve is connected to the water inlet 2012 of the first water pump, and the second port 2042 of the second four-way valve is connected to the first port 2031 of the heater; the water outlet 2011 of the first water pump is connected to the second port 2022 of the heater core; the first port 2021 of the heater core is connected to the second port 2032 of the heater; the pipeline node C is connected to the fourth port 2044 of the second four-way valve, the first port 2051 of the shell and tube phase change heat accumulator and the pipeline node F respectively; the pipeline node D is connected to the third port 2043 of the second four-way valve, the first port 3051 of the first heat exchanger and the water inlet 3012 of the second water pump respectively; the pipeline node F is connected to the pipeline node C, the second port 2062 of the third one-way valve and the second port 2063 of the third three-way valve respectively The first port 2061 of the third one-way valve is connected to the second port 2052 of the shell and tube phase change heat accumulator; the water outlet 3011 of the second water pump is connected to the second port 3022 of the power battery; the first port 3031 of the third four-way valve is connected to the second port 3042 of the second three-way valve, the second port 3032 of the third four-way valve is connected to the first port 3021 of the power battery, the third port 3033 of the third four-way valve is connected to the second port 4062 of the outdoor radiator, and the fourth port 3034 of the third four-way valve is connected to the first port 4051 of the second heat exchanger; the pipeline node G is respectively connected to the first port 4061 of the outdoor radiator, the water inlet 4012 of the third water pump and the third port 4043 of the third three-way valve;The third water pump outlet 4011 is connected to the second port 4022 of the motor controller; the first port 4021 of the motor controller is connected to the second port 4032 of the drive motor; the second port 4042 of the third three-way valve is connected to the first port 4031 of the drive motor, and the first port 4041 of the third three-way valve is connected to the second port 4052 of the second heat exchanger.

[0072] Figure 1 The vehicle thermal management system 100 also includes a control module 8000. The control module 8000 controls the refrigerant flow rate by controlling the compressor 101; the control module 8000 controls the coolant flow rate by controlling the first water pump 201, the second water pump 301 and the third water pump 401; the control module 8000 controls the air flow rate by controlling the fan 501 and the blower 502; the control module 8000 controls the heating power by controlling the heater 203; the control module 8000 adjusts the circulation circuit of the refrigerant and the coolant by controlling the on-off state of the first electronic expansion valve 104, the second electronic expansion valve 111, the third electronic expansion valve 109, the first four-way valve 102, the second four-way valve 204, the third four-way valve 303, the first single-way valve 106, the second single-way valve 108, the third single-way valve 206, the first three-way valve 110, the second three-way valve 304 and the third three-way valve 404.

[0073] Figure 2-7 yes Figure 1 The control module shown in the figure controls the logic flow chart of the switching of different working modes. By monitoring the temperature of the passenger compartment, the battery temperature and the temperature of the electric drive outlet, it switches to the corresponding working mode according to the corresponding judgment logic. Figure 2-7 The control logic flow chart shown.

[0074] Figure 2 yes Figure 1 The control module shown in the figure has a logic flow chart of switching the operating mode based on the passenger compartment temperature. Figure 2 As shown, after the vehicle is started, the temperature of the passenger compartment is monitored by the temperature sensor. When the temperature of the passenger compartment is less than 16°C, it is further determined whether there is waste heat from the battery and electric drive that can be used. If so, the heat pump air conditioning and waste heat heating passenger compartment mode is adopted. If not, it is further determined whether the ambient temperature is less than -15°C. If so, the heat storage device and heater are used to assist the heat pump air conditioning in heating the passenger compartment mode. Otherwise, the heat storage device is used to assist the heat pump air conditioning in heating the passenger compartment mode. When the temperature of the passenger compartment is greater than 26°C, the heat pump air conditioning is used to cool the passenger compartment mode.

[0075] Figure 3 yes Figure 1 The control module shown in the figure has a logic flow chart for switching the working mode based on the battery temperature. Figure 3As shown, after the vehicle is started, the temperature of the battery coolant outlet is monitored by the temperature sensor, and then the battery heat generation model is used to determine the power battery temperature. When the battery temperature is less than 20°C, it is further determined whether there is electric drive waste heat that can be used. If so, the electric drive waste heat is used to assist the heat pump air conditioner to heat the battery mode. If not, it is further determined whether the ambient temperature is less than -15°C. If so, the heat storage device and PTC are used to assist the heat pump air conditioner to heat the battery mode. Otherwise, the heat storage device is used to assist the heat pump air conditioner to heat the battery mode. When the power battery temperature is greater than 30°C, the passenger compartment temperature is further determined. If Not less than 16℃, further determine whether the ambient temperature is less than 20℃, if so, use the radiator to cool the battery mode, otherwise, use the heat pump air conditioning to cool the battery mode, if the passenger compartment temperature is less than 16℃, further determine whether the available waste heat of the battery is greater than the heating demand of the passenger compartment, if not, use the battery waste heat to heat the passenger compartment, that is, the heat pump air conditioning to cool the battery mode, otherwise, further determine whether the heat storage capacity of the phase change heat accumulator is sufficient, if not, use the battery waste heat to heat the passenger compartment and the heat accumulator heat storage mode, otherwise, use the battery waste heat to heat the passenger compartment and the radiator to cool the battery mode.

[0076] Figure 4 yes Figure 1 The control module shown in FIG. 1 is a logic flow chart of the switching of the working mode based on the temperature of the electric drive outlet. Figure 4 As shown, after the vehicle is started, the temperature of the electric drive water outlet is monitored by the temperature sensor. When the temperature of the electric drive system is less than 60°C, the motor self-insulation mode is started; when the temperature of the electric drive system is greater than 60°C, it is further determined whether the temperature of the passenger compartment is less than 16°C or the temperature of the power battery is less than 20°C, that is, whether the vehicle system requires waste heat. If not, it is further determined whether the ambient temperature is less than 20°C. If so, the radiator cooling electric drive mode is adopted. Otherwise, the heat pump air conditioning cooling electric drive mode is adopted. If waste heat is needed, it is further determined whether the waste heat available for the electric drive is greater than the heating demand of the battery and the passenger compartment. If not, the electric drive waste heat recovery mode is adopted, that is, the heat pump air conditioning cooling electric drive mode. Otherwise, it is further determined whether the heat storage capacity of the phase change heat accumulator is sufficient. If not, the electric drive waste heat heating and phase change heat accumulator heat storage modes are adopted. Otherwise, the electric drive waste heat heating and radiator cooling electric drive modes are adopted.

[0077] Figure 5 yes Figure 1 The control module shown in the figure shows the logic flow chart of the utilization of the residual heat of the whole vehicle after parking. Figure 5As shown, after the vehicle stops, the ambient temperature is monitored by the temperature sensor to see if it is less than 15°C, and whether the car will be restarted in a short time is determined based on the driver's instructions. If not, it is further determined whether the heat storage capacity of the phase change heat accumulator is sufficient. If sufficient, the radiator heat dissipation mode is adopted. Otherwise, the phase change heat accumulator heat storage mode is adopted. If all are satisfied, it is further determined whether the residual heat of the electric drive and the battery meets the insulation and heating requirements of the battery and the passenger compartment. If not, the self-insulation mode of the battery and the passenger compartment is adopted. Otherwise, it is further determined whether the heat storage capacity of the phase change heat accumulator is sufficient. If sufficient, the self-insulation and radiator heat dissipation modes of the battery and the passenger compartment are adopted. Otherwise, the self-insulation and phase change heat storage modes of the battery and the passenger compartment are adopted.

[0078] Figure 6 yes Figure 1 The battery fast charging temperature control logic flow chart of the control module shown in FIG. Figure 6 As shown, when the battery starts to charge quickly, its temperature is very likely to be too high, so first determine whether the battery temperature is less than 30°C. If so, start the battery self-insulation mode and do not cool the battery. Otherwise, further determine whether the battery temperature is greater than 40°C. If so, use the heat pump air conditioner and radiator to cool the battery. Otherwise, use the radiator alone to cool the battery.

[0079] Figure 7 yes Figure 1 The outdoor heat exchanger defrost control logic flow chart of the control module is shown in FIG. Figure 7 As shown, when the ambient temperature is monitored by the temperature sensor and the humidity sensor to be within the range of 0-5°C and the air humidity is greater than 70%, it is very easy to generate frost on the heat exchanger. Then, it is determined whether the heating efficiency of the heat pump decreases under the same working condition. If the heating efficiency decreases, the defrosting mode of the outdoor heat exchanger 105 is started, and the heat storage device and waste heat auxiliary heating mode are used at the same time to keep the battery and the passenger compartment in the optimal temperature area. Otherwise, the cycle monitoring is continued.

[0080] The above is the control logic for switching between different working modes of the control module. After switching to the corresponding working mode, in order to optimize the thermal comfort of the passenger compartment and the operating temperature of the battery and electric drive, it is also necessary to adopt corresponding control methods to adjust the compressor speed, electronic expansion valve opening and water pump speed to optimize the temperature of the passenger compartment, power battery and electric drive. The control methods of the compressor speed, electronic expansion valve opening and water pump speed will be described in detail below.

[0081] The heat pump air conditioning system of pure electric vehicles uses model predictive control to adjust the compressor speed. The effectiveness of the model predictive controller depends on an accurate mathematical model, but the air conditioning system has dynamic nonlinearity, coupling, and multi-input and multi-output characteristics. It is impossible to achieve the target value of the passenger compartment temperature by directly adjusting the compressor speed. The coupling effect of other variables needs to be considered. Therefore, it is necessary to establish a state space model to fully describe its dynamic behavior and provide a basis for the model predictive controller to predict future states and optimize control inputs, thereby achieving comprehensive optimization of system performance, stability, and energy consumption.

[0082] On this basis, the compressor speed controlled by the model predictive controller is used as one of the input variables u(k) of the state space model of the air conditioning system, and the passenger compartment temperature (so C is the unit matrix at this time), which is one of the output variables y(k) of the state space model of the air conditioning system, is fed back to the model predictive controller as a measurable input. The model predictive controller uses the state space model of the air conditioning system to predict the future trend of the passenger compartment temperature, compares it with the target temperature of the passenger compartment, and adjusts the compressor speed based on the optimization algorithm. The adjusted compressor speed is used as a new input and fed back to the state space model to iterate the prediction and optimization process.

[0083] Firstly, the state space model of the heat pump air conditioning system is established and the black box model is used for modeling.

[0084] Assume that the relationship between the state quantity and control quantity of the air conditioning system at a certain moment is:

[0085]

[0086] in, is the derivative of the state quantity, that is, the rate of change of the system state quantity; ξ r is the state quantity of the system; u r is the control quantity of the system.

[0087] At any reference point, the above relationship can be expanded using Taylor series and only the first-order terms are retained to obtain an approximate linear model of the system:

[0088]

[0089] Among them, ξ is the state quantity of the system at the reference point; u is the control quantity of the system at the reference point; J f (ξ), J f (u) are the Jacobian matrices of f(ξ,u) with respect to the state variable ξ and the control variable u, respectively, and

[0090] make A(t)=J f (ξ), B(t) = J f(u), subtract equation (1) from equation (2) to get the new state equation:

[0091]

[0092] in, It represents the derivative of the deviation state quantity, that is, the rate of change of the state deviation.

[0093] However, equation (3) needs to be discretized before it can be used in controller design. The discretization formula is:

[0094] A k,t =E+T s A(t)(4)

[0095] B k,t =T s B(t)(5)

[0096] Among them, T s is the time step. In order to balance the computational complexity and the accuracy of dynamic response, T is taken s =100ms; E represents the unit matrix.

[0097] Discretizing the new state equation, we can obtain:

[0098]

[0099] Formula (6) is the linear system at a certain reference point obtained by linearizing the nonlinear system.

[0100] Therefore, the discretized state space model expression of the air conditioning system is:

[0101]

[0102] Where x(k+1) represents the state variable of the air conditioning system at the reference time k+1; A x is the state matrix; x(k) represents the state variable of the air conditioning system at discrete time k; B u is the input matrix; u(k) represents the input variable at discrete time k; y(k) represents the output variable at time k; C is the output matrix.

[0103] When the air-conditioning system is in cooling mode, the cabin temperature, compressor intake pressure and battery temperature can be selected as state variables, and the compressor speed, expansion valve opening and water pump speed can be selected as input variables; when heating, the cabin temperature, battery temperature and motor water outlet temperature can be selected as state variables, and the compressor speed, expansion valve opening and water pump speed can be selected as input variables.

[0104] Then the state matrix parameters are identified and the state matrix A is x 、Input matrix Bu Assuming it as an unknown parameter and setting the output matrix C as the unit matrix, the output variable y(k) can be directly output by the state variable x(k).

[0105] Design of model predictive controller. When designing a model predictive controller, the following two objectives need to be met simultaneously to ensure system performance and stability.

[0106] Goal 1 is to get the expected output value close to the target value, and the objective function is:

[0107]

[0108] Among them, y t (k+i) is the passenger compartment temperature predicted by the air conditioning system state space model; w t (k+i) is the target temperature of the passenger compartment; P represents the prediction time domain, that is, the number of time steps for predicting future outputs.

[0109] The second goal is to reduce energy consumption, that is, to reach the target value faster and more accurately. The objective function is:

[0110]

[0111] Where Δu(k) is the rate of change of the compressor speed, and M represents the control time domain, that is, the number of future time steps at which the controller calculates and applies the control action at each sampling moment.

[0112] Combining the above two objectives, the overall objective function J of the model predictive controller is:

[0113] J=J 1 *ω 1 +J 2 *ω 2 (10)

[0114] Among them, ω 1 and ω 2 are the weight coefficients of target one and target two respectively.

[0115] Weight coefficient ω 1 and ω 2 The choice of depends on the priority of the working condition: when ensuring the comfort of the passengers, the weight ω 1 Large, while when emphasizing energy consumption optimization, ω 2 Large. According to the actual working conditions, the balance can be achieved by adaptively adjusting the weight coefficient. By solving the overall objective function, the optimized compressor speed can be obtained, thereby achieving the optimal control target of the passenger compartment and battery temperature.

[0116] The output control variable of the model predictive controller is the compressor speed, and its constraints include the change rate and speed range of the compressor speed:

[0117]

[0118] Among them, Δu max is the maximum compressor speed change rate; u(k) is the compressor speed, u min 、u max They are the lower and upper limits of the compressor speed respectively.

[0119] Electronic expansion valves and water pumps have high requirements for real-time control, so fast-response PID control is adopted. The PID controller first detects the state value of the controlled object through the sensor in real time, and passes the difference e(t) between the target value g(t) and the actual value r(t) as input to the PID controller. The PID controller calculates the specific control output u(t) based on the difference signal e(t), and its expression is:

[0120] e(t)=g(t)-r(t)(12)

[0121]

[0122] Among them, K p , K i , K d They are the proportional coefficient, integral coefficient and differential coefficient of the controller, which are used to adjust the response speed, error elimination and stability.

[0123] The electronic expansion valve adjusts the heat exchange of the refrigerant in the heat exchanger by controlling the superheat of the system. Based on the PID algorithm, the saturated pressure of the refrigerant at the target superheat is taken as the target value, the actual pressure at the heat exchanger outlet is taken as the actual value, and the opening of the electronic expansion valve is taken as the control output.

[0124] The water pump changes the coolant flow rate by adjusting the speed to optimize the heat exchange efficiency, thereby maintaining the battery, motor and motor controller in the optimal operating temperature range.

[0125] In the battery coolant circulation system, in order to calculate the required parameters, a heat generation model of the power battery is established:

[0126]

[0127] Wherein, q is the heat generation power per unit volume of the lithium battery; I is the current of the battery discharge during the vehicle driving process; V is the volume of the lithium battery monomer; R is the sum of the ohmic internal resistance and polarization internal resistance of the lithium battery; T is the ambient temperature of the environment in which the vehicle is driving; U OC is the open circuit voltage.

[0128] The cooling or heating of the power battery is mainly the convection heat exchange between the coolant and the battery through the cooling plate, which is calculated using Newton's formula:

[0129] Q=μAbat (T bat -T l )(15)

[0130] Where: Q is the heat transfer; μ is the convective heat transfer coefficient; A bat is the contact area between the battery and the cooling plate; T bat is the battery temperature; T l is the fluid medium temperature.

[0131] Through the power battery heat generation model and Newton's heat exchange formula, the current battery temperature change trend can be obtained in real time, thereby obtaining the actual battery temperature. The difference between the actual battery temperature and the target temperature is used as the PID control input, and the second water pump speed is used as the output to regulate the coolant flow, thereby achieving a dynamic balance of the battery temperature.

[0132] In the cooling circulation system of the motor and the motor controller, the sensor monitors the actual temperature of the motor water outlet in real time. The controller uses the difference between the target water temperature and the actual water temperature as input and outputs the third water pump speed to optimize the coolant flow distribution, thereby achieving the optimal balance of energy consumption while meeting the heat dissipation requirements.

[0133] Figure 8-17 yes Figure 1 The fluid flow state of the vehicle thermal management system 100 in different working modes is shown, wherein the bold dashed arrows indicate the flow direction and flow path of the refrigerant, the bold solid arrows indicate the flow direction and flow path of the coolant, and the other solid lines indicate no fluid flow. Figure 8-17 The various operating modes are shown.

[0134] Figure 8 for Figure 1The system diagram of the vehicle thermal management system in the heat pump air conditioning heating passenger compartment mode in a low temperature environment is shown. In a low temperature environment, after receiving the passenger compartment heating instruction (or the control module 8000 automatically generates the passenger compartment heating instruction), the vehicle thermal management system 100 can transfer heat to the passenger compartment through the heat pump air conditioning heating passenger compartment mode. Under the control of the control module 8000, the refrigerant is compressed by the compressor 101 and becomes a high-temperature and high-pressure steam refrigerant, which flows out from the compressor exhaust port 1011, passes through the first port 1021 and the second port 1022 of the first four-way valve, and then flows through the pipeline node A to the refrigerant channel of the indoor heat exchanger 103. At this time, the indoor heat exchanger 103 acts as a condenser. Under the condensation effect, the refrigerant liquefies and releases heat to heat the indoor air. In addition, the blower 502 promotes air circulation, so that the temperature of the entire passenger compartment rises evenly. After liquefaction, the medium-temperature and high-pressure liquid refrigerant passes through the pipeline node E to the first electronic expansion valve 104, which will reduce pressure and increase volume, and become a low-temperature and low-pressure liquid mist refrigerant, and then passes through the pipeline node H Flows to the outdoor heat exchanger 105, at which time the outdoor heat exchanger 105 acts as an evaporator. In addition, the fan 501 promotes air circulation, so that the refrigerant can more fully absorb the heat in the air in the outdoor heat exchanger 105, and become a low-temperature and low-pressure gas-liquid mixture, and then passes through the first one-way valve 106, the pipeline node I, the fourth port 1024 of the first four-way valve and the third port 1023 of the first four-way valve in sequence, and reaches the gas-liquid separator inlet 1072. After the liquid refrigerant and the gaseous refrigerant are separated by the gas-liquid separator 107, the liquid refrigerant remains in the gas-liquid separator 107, and the gaseous refrigerant enters the compressor 101 from the compressor air inlet 1012, and the next refrigerant cycle starts.

[0135] Fig. 9 for Figure 1The system diagram of the vehicle thermal management system in the heat pump air conditioning heating battery mode in a low temperature environment is shown. In a low temperature environment, when the battery temperature is lower than the appropriate operating temperature and the heat storage device is insufficient, the control module 8000 generates a battery heating instruction. After receiving the battery heating instruction, the vehicle thermal management system 100 can transfer heat to the battery through the heat pump air conditioning heating battery mode. Under the control of the control module 8000, the refrigerant is compressed by the compressor 101 and becomes a high-temperature and high-pressure steam refrigerant. After flowing out from the compressor exhaust port 1011, it passes through the first port 1021 and the second port 1022 of the first four-way valve, the pipeline node A, the second one-way valve 108 and the third port 3053 of the first heat exchanger to the first heat exchanger 305 in sequence. At this time, the first heat exchanger 305 acts as a condenser. Under the condensation effect, the refrigerant liquefies and releases heat to heat the coolant. After liquefaction, the medium-temperature and high-pressure liquid refrigerant flows out from the fourth port 3054 of the first heat exchanger to the third electronic expansion valve 109. Under the action of the third electronic expansion valve 109, the refrigerant will be decompressed and the volume will increase, becoming a low-temperature and low-pressure liquid mist refrigerant, and then flow through the pipeline node H. Toward the outdoor heat exchanger 105, at this time the outdoor heat exchanger 105 acts as an evaporator. In addition, the fan 501 promotes air circulation, so that the refrigerant can more fully absorb the heat in the air in the outdoor heat exchanger 105. The refrigerant absorbs the heat in the air in the outdoor heat exchanger 105 and becomes a low-temperature and low-pressure gas-liquid mixture. Then, it passes through the first one-way valve 106, the pipeline node I, the fourth port 1024 of the first four-way valve and the third port 1023 of the first four-way valve in sequence, and reaches the gas-liquid separator inlet 1072. After the liquid refrigerant and the gaseous refrigerant are separated by the gas-liquid separator 107, the liquid refrigerant remains in the gas-liquid separator 107, and the gaseous refrigerant enters the compressor 101 from the compressor air inlet 1012, and the next refrigerant cycle starts. On the other hand, the high-temperature coolant discharged from the water outlet 3011 of the second water pump enters the power battery 302, and after releasing heat to heat the power battery 302, becomes low-temperature coolant, and then passes through the second port 3032 and the first port 3031 of the third four-way valve, the second port 3042 and the third port 3043 of the second three-way valve, and the second port 3052 of the first heat exchanger to the first heat exchanger 305, absorbs the heat released by the refrigerant and becomes high-temperature coolant, then flows out from the first port 3051 of the first heat exchanger, flows back to the water inlet 3012 of the second water pump, enters the second water pump 301, and starts the next coolant cycle.

[0136] Fig.10 for Figure 1The system diagram of the vehicle thermal management system in the low temperature environment heater and heat storage mode for heating the passenger compartment and battery is shown. In the low temperature environment, when the heat storage has sufficient heat, the battery temperature is lower than the appropriate operating temperature and the passenger compartment needs to be heated, the control module 8000 generates a battery heating and passenger compartment heating instruction. After receiving the battery heating and passenger compartment heating instructions, the vehicle thermal management system 100 can transfer heat to the battery and passenger compartment through the heater and heat storage mode for heating the passenger compartment and battery. Under the control of the control module 8000, the coolant is discharged from the second water pump outlet 3011 and enters the power battery 302. After releasing heat to heat the power battery 302, it becomes a low-temperature coolant, and then passes through the second port 3032 and the first port 3031 of the third four-way valve, the second port 3042 and the first port 3041 of the second three-way valve, the pipeline node F, the third one-way valve 206 and the second port 2052 of the shell and tube phase change heat accumulator to the shell and tube phase change heat accumulator 205. After the coolant absorbs the heat released by the phase change of the phase change material inside the shell and tube phase change heat accumulator 205, it flows out from the first port 2051 of the shell and tube phase change heat accumulator, passes through the pipeline node C, the second four-way valve 206 and the second port 2052 of the shell and tube phase change heat accumulator, and then enters the shell and tube phase change heat accumulator 205. After the fourth port 2044 and the first port 2041 of the through valve, it reaches the first water pump 201 and then flows to the heater core 202. The high-temperature coolant releases heat to heat the indoor air. In addition, the blower 502 promotes air circulation to evenly increase the temperature of the entire passenger compartment. The coolant flows from the heater core 202 to the heater 203. When the coolant temperature is not enough to meet the heating requirements of the battery and the passenger compartment, the heater 203 can be used to assist in heating the coolant to ensure sufficient heat. The coolant passes through the first port 2031 of the heater, the second port and the third port of the second four-way valve, the pipeline node D and the second water pump inlet 3012 in turn, and then reaches the second water pump 301 to start the next coolant cycle.

[0137] Fig.11 for Figure 1The system diagram of the vehicle thermal management system in the battery self-insulation mode in a low-temperature environment is shown. In a low-temperature environment, when the car is parked for a short time, in order to prevent the battery temperature from being too low when the car is restarted, the battery must be heated additionally. Therefore, the heat from the electric drive waste heat recovery and the heat stored in the heat accumulator can be used to keep the battery warm and reduce energy consumption. Under the control of the control module 8000, the coolant is discharged from the second water pump outlet 3011 and enters the power battery 302. After releasing heat to heat the power battery 302, it becomes a low-temperature coolant, and then passes through the second port 3032 and the third port 3033 of the third four-way valve to the inside of the outdoor radiator 406. At this time, the fan 501 is not started to reduce the waste heat dissipated into the air. The coolant then flows out from the outdoor radiator 406, passes through the pipeline node G, the third water pump 401, the motor controller 402 and the drive motor 403 in sequence. The coolant absorbs waste heat from the motor controller 402 and the drive motor 403 of the electric drive system, and then passes through the second port 4042 and the first port 4041 of the third three-way valve, the second port 4052 of the second heat exchanger and the first port 4053 of the third heat exchanger in sequence. The first port 4051, the fourth port 3034 and the third port 3033 of the third four-way valve, the second port and the first port of the second three-way valve, the pipeline intersection F, the third one-way valve 206 and the second port 2052 of the shell and tube type phase change heat accumulator to the shell and tube type phase change heat accumulator 205; when the residual heat of the motor is insufficient, the coolant absorbs the heat released by the phase change of the phase change material inside the shell and tube type phase change heat accumulator 205, and when the residual heat is excessive, the shell and tube type phase change heat accumulator 205 absorbs the residual heat, and then the coolant flows out from the first port 2051 of the shell and tube type phase change heat accumulator, passes through the pipeline node C, the fourth port 2044 and the third port 2043 of the second four-way valve, the pipeline intersection D and the second water pump inlet 3012 in sequence to the second water pump 301, and starts the next coolant cycle.

[0138] Fig.12 for Figure 1The system diagram of the vehicle thermal management system in the waste heat recovery mode of the battery and electric drive in a low temperature environment is shown. When the car stops running and will not be restarted in a short time, the waste heat of the battery and electric drive needs to be recovered; or when the battery and electric drive temperature is too high after the car has been driving in a low temperature environment for a period of time, they need to be cooled. At the same time, the heating efficiency of the heat pump air conditioner is low at low temperatures, and it is difficult to absorb heat from the outdoor air. Therefore, absorbing heat from the battery and electric drive not only improves the heating efficiency of the heat pump, but also cools the battery and electric drive. Under the control of the control module 8000, the refrigerant is compressed by the compressor 101 and becomes a high-temperature and high-pressure steam refrigerant. After flowing out from the compressor exhaust port 1011, it passes through the first port 1021 and the second port 1022 of the first four-way valve to the pipeline node A, and then flows through the pipeline node A to the refrigerant channel of the indoor heat exchanger 103. At this time, the indoor heat exchanger 103 acts as a condenser. Under the condensation action, the refrigerant liquefies and releases heat to heat the indoor air. In addition, the blower 502 promotes air circulation, so that the temperature of the entire passenger compartment rises evenly. After liquefaction, the medium-temperature and high-pressure liquid refrigerant passes through the pipeline node E to the second electronic expansion valve 111, where it will reduce pressure and increase volume, becoming a low-temperature and low-pressure liquid mist refrigerant. The refrigerant from the second electronic expansion valve 111 will be discharged from the second electronic expansion valve 111. The expansion valve 111 flows out to the third port 4053 of the second heat exchanger, enters the second heat exchanger 405, absorbs the heat of the coolant, and evaporates to become a low-temperature and low-pressure gas-liquid mixture. At this time, the second heat exchanger acts as an evaporator, and the refrigerant flows out from the fourth port 4054 of the second heat exchanger, passes through the second port and the first port of the first three-way valve, the pipeline node I, the fourth port 1024 of the first four-way valve, and the third port 1023, and then reaches the gas-liquid separator inlet 1072. After the liquid refrigerant and the gaseous refrigerant are separated by the gas-liquid separator 107, the liquid refrigerant remains in the gas-liquid separator 107, and the gaseous refrigerant enters the compressor 101 from the compressor air inlet 1012, and the next refrigerant cycle starts. On the other hand, the coolant circulation in this mode is the same as the circulation in the above-mentioned battery self-insulation mode, which will not be repeated here.

[0139] Fig.13 for Figure 1The system diagram of the vehicle thermal management system in the outdoor heat exchanger defrosting mode in a low-temperature environment is shown. In a low-temperature environment, the outdoor heat exchanger defrosts frequently, which reduces the heating efficiency of the heat pump air conditioner. The outdoor heat exchanger needs to be defrosted. At the same time, in order to ensure the thermal comfort of the passenger compartment in low temperatures, the residual heat of the battery and motor and the stored heat of the heat accumulator are used to heat the passenger compartment. Under the control of the control module 8000, the refrigerant is compressed by the compressor 101 and becomes a high-temperature and high-pressure steam refrigerant, which flows out from the compressor exhaust port 1011, passes through the first port 1021 and the fourth port 1024 of the first four-way valve, and then flows to the refrigerant channel of the outdoor heat exchanger 105 through the pipeline node I and the first one-way valve 106. At this time, the outdoor heat exchanger 105 acts as a condenser. Under the condensation action, the refrigerant liquefies and releases heat, heats the fins of the outdoor heat exchanger 105, and melts the frost on the surface of the fins. After liquefaction, the medium-temperature and high-pressure liquid refrigerant passes through the pipeline node H to the first electronic expansion valve 104, where it will reduce pressure and increase volume, becoming a low-temperature and low-pressure liquid mist refrigerant, and then passes through the pipeline node E, the second electronic expansion valve 111 and The third port 4053 of the second heat exchanger enters the second heat exchanger 405, absorbs the heat released by the coolant and becomes a low-temperature and low-pressure gas-liquid mixture, flows out from the fourth port 4054 of the second heat exchanger, passes through the second port 1102 and the third port 1103 of the first three-way valve, the pipeline intersection B, the second one-way valve 108, the pipeline intersection A, the second port 1022 of the first four-way valve and the third port 1023 of the first four-way valve in sequence, and reaches the gas-liquid separator inlet 1072. After the liquid refrigerant and the gaseous refrigerant are separated by the gas-liquid separator 107, the liquid refrigerant remains in the gas-liquid separator 107, and the gaseous refrigerant enters the compressor 101 from the compressor air inlet 1012, and the next refrigerant cycle starts. On the other hand, the coolant cycle in this mode is a combination of the above-mentioned heater and heat storage device heating passenger compartment and battery mode and the cycle in the battery self-insulation mode, which will not be repeated here.

[0140] Fig.14 for Figure 1The system diagram of the vehicle thermal management system in the heat pump air conditioning cooling battery and electric drive mode in a medium temperature environment is shown. In a medium temperature environment, when the car is driving, the battery and electric drive will be too hot and need to be cooled in time. At this time, there is no cooling or heating demand in the passenger compartment, and the heat pump and radiator can be used to directly cool the battery and electric drive. Under the control of the control module 8000, the refrigerant is compressed by the compressor 101 and becomes a high-temperature and high-pressure vapor refrigerant. It flows out from the compressor exhaust port 1011, passes through the first port 1021 and the fourth port 1024 of the first four-way valve, and then flows to the refrigerant channel of the outdoor heat exchanger 105 through the pipeline node I and the first one-way valve 106. At this time, the outdoor heat exchanger 105 acts as a condenser. Under the action of condensation, the refrigerant liquefies and releases heat. After liquefaction, the medium-temperature and high-pressure liquid refrigerant passes through the pipeline node H. When it reaches the third electronic expansion valve 104, it will reduce the pressure and increase the volume, becoming a low-temperature and low-pressure liquid mist refrigerant. The refrigerant flows from the third electronic expansion valve 104 to the first The fourth port 3054 of the heat exchanger enters the first heat exchanger 305, absorbs the heat of the coolant and evaporates to become a low-temperature and low-pressure gas-liquid mixture, and then flows from the third port 3053 of the first heat exchanger through the pipeline node B, the second one-way valve 108, the pipeline intersection A, the second port 1022 of the first four-way valve and the third port 1023 of the first four-way valve to reach the gas-liquid separator inlet 1072. After the liquid refrigerant and the gaseous refrigerant are separated by the gas-liquid separator 107, the liquid refrigerant remains in the gas-liquid separator 107, and the gaseous refrigerant enters the compressor 101 from the compressor air inlet 1012 to start the next refrigerant cycle. On the other side, the coolant is discharged from the second water pump outlet 3011 and enters the power battery 302. After absorbing the heat of the power battery 302, it passes through the second port 3032 and the third port 3033 of the third four-way valve in sequence to the inside of the outdoor radiator 406. At this time, the fan 501 promotes air circulation to allow the coolant to fully dissipate heat. The coolant then flows out of the outdoor radiator 406 and passes through the pipeline node G, the third water pump 401, the motor controller 402 and the drive motor 403 in sequence. The coolant absorbs heat from the motor controller 402 and the drive motor 403 of the electric drive system, and then passes through the third four-way valve in sequence. The second port 4042 and the first port 4041 of the three-way valve, the second port 4052 and the first port 4051 of the second heat exchanger, the fourth port 3034 and the first port 3033 of the third four-way valve, the second port 3042 and the third port 3043 of the second three-way valve flow to the second port 3052 of the first heat exchanger, enter the first heat exchanger 305, release heat to the refrigerant, and the cooled low-temperature refrigerant flows out from the first port 3051 of the first heat exchanger, passes through the pipeline node D and the second water pump inlet 3012 in sequence, and then enters the second water pump 301 to start the next coolant cycle.

[0141] Fig.15 for Figure 1The system diagram of the vehicle thermal management system in the heat pump air conditioning cooling passenger compartment mode in a high temperature environment is shown. In a high temperature environment, the vehicle thermal management system 100 can transfer the heat of the passenger compartment to the outdoor air through the heat pump air conditioning cooling passenger compartment mode after receiving the passenger compartment cooling command (or the control module 8000 automatically generates the passenger compartment cooling command). Under the control of the control module 8000, the refrigerant is compressed by the compressor 101 and becomes a high-temperature and high-pressure vapor refrigerant, which flows out from the compressor exhaust port 1011, passes through the first port 1021 and the fourth port 1024 of the first four-way valve, passes through the pipeline node I and the first one-way valve 106, and flows to the refrigerant channel of the outdoor heat exchanger 105. At this time, the outdoor heat exchanger 105 acts as a condenser, and the refrigerant liquefies and releases heat under the action of condensation. In addition, the fan 501 promotes air circulation, so that the refrigerant dissipates heat faster and more fully. After liquefaction, the medium-temperature and high-pressure liquid refrigerant passes through the pipeline node H to the first electronic expansion valve 104, which will reduce the pressure and increase the volume, becoming a low-temperature and low-pressure liquid mist refrigerant, and then flows through the pipeline node E to Indoor heat exchanger 103, at this time, the indoor heat exchanger 103 acts as an evaporator. In addition, the blower 502 promotes air circulation, so that the refrigerant can more fully absorb the heat in the air in the indoor heat exchanger 103, so that the temperature of the entire passenger cabin drops evenly, and becomes a low-temperature and low-pressure gas-liquid mixture, and then passes through the pipeline node A, the second port 1022 of the first four-way valve and the third port 1023 of the first four-way valve in sequence, and reaches the gas-liquid separator inlet 1072. After the liquid refrigerant and the gaseous refrigerant are separated by the gas-liquid separator 107, the liquid refrigerant remains in the gas-liquid separator 107, and the gaseous refrigerant enters the compressor 101 from the compressor air inlet 1012 to start the next refrigerant cycle.

[0142] Fig.16 for Figure 1The system diagram of the vehicle thermal management system in the battery super cooling mode during fast charging is shown. During fast charging, especially in hot summer weather, the battery is prone to overheating, so the super cooling mode is needed to quickly cool the battery to keep it stable. Under the control of the control module 8000, the refrigerant is compressed by the compressor 101 and becomes a high-temperature and high-pressure steam refrigerant, flows out from the compressor exhaust port 1011, passes through the first port 1021 and the fourth port 1024 of the first four-way valve, passes through the pipeline node I and the first one-way valve 106, and flows to the refrigerant channel of the outdoor heat exchanger 105. At this time, the outdoor heat exchanger 105 acts as a condenser. Under the condensation action, the refrigerant liquefies and releases heat. In addition, the fan 501 promotes air circulation, so that the refrigerant dissipates heat faster and more fully. After liquefaction, the medium-temperature and high-pressure liquid refrigerant passes through the pipeline node H, and then passes through the branch 1 (the refrigerant will reduce pressure and increase volume when it reaches the first electronic expansion valve 104, and become a low-temperature and low-pressure liquid mist refrigerant), and flows to the indoor heat exchanger 103 through the pipeline node E. At this time, the indoor heat exchanger 103 acts as an evaporator. In addition, the blower 502 promotes air circulation, so that the refrigerant absorbs heat from the air more fully in the indoor heat exchanger 103, so that the whole The temperature of each passenger compartment drops evenly, becoming a low-temperature and low-pressure gas-liquid mixture, and then flows to the pipeline node A) and branch 2 (the refrigerant will be decompressed and increase in volume when it reaches the third electronic expansion valve 109, becoming a low-temperature and low-pressure liquid mist refrigerant, and then flows to the fourth port 3054 of the first heat exchanger, enters the first heat exchanger 305, absorbs the heat of the coolant and evaporates to become a low-temperature and low-pressure gas-liquid mixture, and then flows out from the third port 3053 of the first heat exchanger, passes through the pipeline intersection B and the second one-way valve 108, and flows to the pipeline node A) and converges to the pipeline node A, and then passes through the second port 1022 of the first four-way valve and the third port 1023 of the first four-way valve, and reaches the gas-liquid separator inlet 1072. After the gas-liquid separator 107 separates the liquid refrigerant and the gaseous refrigerant, the liquid refrigerant remains in the gas-liquid separator 107, and the gaseous refrigerant enters the compressor 101 from the compressor air inlet 1012 to start the next refrigerant cycle.On the other hand, the ultra-low temperature coolant is discharged from the second water pump outlet 3011 and enters the power battery 302. After fully absorbing the heat of the power battery 302, it passes through the second port 3032 and the third port 3033 of the third four-way valve in sequence and reaches the interior of the outdoor radiator 406. At this time, the fan 501 promotes air circulation to fully dissipate the heat of the coolant. The coolant then flows out of the outdoor radiator 406 and passes through the pipeline node G, the third port 4043 and the first port 4041 of the third three-way valve and the second port 4052 of the second heat exchanger in sequence to release the heat in the second heat exchanger 405. The cooled coolant flows out from the first port 4051 of the second heat exchanger, passes through the fourth port 3034 and the first port 3033 of the third four-way valve, the second port 3042 and the third port 3043 of the second three-way valve in sequence, flows to the second port 3052 of the first heat exchanger, enters the first heat exchanger 305, releases heat to the refrigerant again, and the ultra-low temperature refrigerant after secondary cooling flows out from the first port 3051 of the first heat exchanger, passes through the pipeline node D and the second water pump inlet 3012 in sequence, and then enters the second water pump 301, starting the next coolant cycle.

[0143] Fig.17 for Figure 1 The system diagram of the vehicle thermal management system in a high-temperature environment with a heat pump air conditioner cooling the battery and electric drive is shown. In a high-temperature environment, the battery and electric drive are prone to overheating and need to dissipate heat quickly. At the same time, the passenger compartment also needs to be cooled. For this reason, the two heat exchangers and the outdoor radiator in the heat pump air conditioner cycle are activated at the same time to cool the passenger compartment, battery and electric drive. The refrigerant cycle in this mode is a combination of the heat pump air conditioner cooling passenger compartment mode and the battery super cooling mode. The coolant cycle is the same as the heat pump air conditioner cooling battery and electric drive mode, so it will not be repeated here.

[0144] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. A thermal management system for a pure electric vehicle based on a shell and tube phase change heat storage device, characterized in that: Including heat pump air conditioning system, electric heating and phase change thermal storage system, battery thermal management system and electric drive cooling system; The heat pump air conditioning system comprises a compressor (101), a first four-way valve (102), an indoor heat exchanger (103), a first electronic expansion valve (104), an outdoor heat exchanger (105), a first single-way valve (106) and a gas-liquid separator (107) which are connected in sequence; the first four-way valve (102) is also connected to the gas-liquid separator (107); the first four-way valve (102) is also connected to the second single-way valve (108), the first heat exchanger (305), the third electronic expansion valve (109), the first electronic expansion valve (104), the second electronic expansion valve (111), the second heat exchanger (405) and the first three-way valve (110) in sequence through a node A; two ports of the first three-way valve (110), one of which is connected to a port of the first four-way valve (102) and a port of the first single-way valve (106) through a node I, and the other of which is connected to a port of the second single-way valve (108) and the first heat exchanger (305) through a node B; The electric heating and phase-change heat storage system comprises a first water pump (201), a warm air core (202), a heater (203), a second four-way valve (204), a shell-and-tube phase-change heat storage device (205) and a third one-way valve (206) which are connected in sequence; one port of the third one-way valve (206) is connected to a node C and a port of the second three-way valve (304) through a node F; one port of the second four-way valve (204) is connected to the first water pump (201); the node C is also connected to the second four-way valve (204) and the shell-and-tube phase-change heat storage device (205); The battery thermal management system comprises a second water pump (301), a power battery (302), a third four-way valve (303), a second three-way valve (304) and a first heat exchanger (305) which are connected in sequence; the first heat exchanger (305) is connected to the second water pump (301) and the second four-way valve (204) respectively through a node D; The electrically driven cooling system comprises a third water pump (401), a motor controller (402), a drive motor (403), a third three-way valve (404), a second heat exchanger (405), a third four-way valve (303) and an outdoor radiator (406) which are connected in sequence; one port of the third three-way valve (404) is connected to the outdoor radiator (406) and the third water pump (401) respectively through a node G.

2. The thermal management system for a pure electric vehicle according to claim 1, characterized in that: The system also includes a fan (501) and a blower (502), wherein the fan (501) is arranged at the outdoor radiator (406), and the blower (502) is arranged at the indoor heat exchanger (103); the outdoor heat exchanger (105) and the outdoor radiator (406) are integrated in design, the outdoor heat exchanger (105) is located on the outside, and the outdoor radiator (406) is located on the inside; when the fan (501) is in operation, air is blown from the outdoor radiator (406) to the outdoor heat exchanger (105) to remove system heat.

3. The thermal management system for a pure electric vehicle according to claim 1, characterized in that: The heat pump air conditioning system is connected to the battery thermal management system via a first heat exchanger (305), the heat pump air conditioning system is connected to the electric drive cooling system via a second heat exchanger (405), the battery thermal management system is connected to the electric drive cooling system via a third four-way valve (303), and the electric heating and phase change heat storage system and the battery thermal management system are connected via a second four-way valve (204), a third one-way valve (206) and a second three-way valve (304).

4. The thermal management system for a pure electric vehicle according to claim 1, characterized in that: The invention also includes a control module (8000), which is respectively connected to the compressor (101), the first four-way valve (102), the first electronic expansion valve (104), the second electronic expansion valve (111), the third electronic expansion valve (109), the first single-way valve (106), the second single-way valve (108), the first three-way valve (110), the first water pump (201), the warm air core (202), the heater (203), the second four-way valve (204), the third single-way valve (206), the second water pump (301), the third four-way valve (303), the second three-way valve (304), the third water pump (401), the third three-way valve (404), the fan (501) and the blower (502).

5. A control method for a thermal management system of a pure electric vehicle according to any one of claims 1 to 4, characterized in that: The control module (8000) controls the speed of the compressor and the opening of the electronic expansion valve to adjust the refrigerant flow; the control module (8000) controls the speed of each water pump to adjust the coolant flow; the control module (8000) controls the fan and the blower to adjust the air flow, controls the on / off state of each four-way valve, three-way valve, and single-way valve, and adjusts the circulation circuit of the refrigerant and the coolant, thereby realizing energy coupling between different systems and switching between different working modes.

6. The control method according to claim 5, characterized in that: The switching of different working modes is as follows: Determine whether the vehicle is in the start-up state. When the vehicle is started, monitor the passenger compartment temperature, battery temperature and electric drive water outlet temperature; When the passenger compartment temperature is less than 16°C, further determine whether there is waste heat from the battery and electric drive that can be used. If so, use the heat pump air conditioner and waste heat to heat the passenger compartment. If not, further determine whether the ambient temperature is less than -15°C. If so, use the heat storage device and PTC to assist the heat pump air conditioner to heat the passenger compartment. Otherwise, use the heat storage device to assist the heat pump air conditioner to heat the passenger compartment. When the passenger compartment temperature is greater than 26°C, use the heat pump air conditioner to cool the passenger compartment. When the power battery temperature is less than 20°C, further determine whether there is electric drive waste heat that can be used. If so, use the electric drive waste heat to assist the heat pump air conditioner to heat the battery mode. If not, further determine whether the ambient temperature is less than -15°C. If so, use the heat storage device and PTC to assist the heat pump air conditioner to heat the battery mode. Otherwise, use the heat storage device to assist the heat pump to heat the battery mode. When the power battery temperature is greater than 30°C, further determine the passenger compartment temperature. If it is not less than 16°C, further determine whether the ambient temperature is less than 20°C. If so, use the radiator to cool the battery mode. Otherwise, use the heat pump air conditioner to cool the battery mode. If the passenger compartment temperature is less than 16°C, further determine whether the battery's available waste heat is greater than the passenger compartment heating demand. If not, use the battery waste heat to heat the passenger compartment, that is, the heat pump air conditioner to cool the battery mode. Otherwise, further determine whether the phase change heat storage heat is sufficient. If not, use the battery waste heat to heat the passenger compartment and the heat storage heat storage mode. Otherwise, use the battery waste heat to heat the passenger compartment and the radiator to cool the battery mode. When the temperature of the electric drive system is less than 60°C, the motor self-insulation mode is started; when the temperature of the electric drive system is not less than 60°C, it is further determined whether the temperature of the passenger compartment is less than 16°C or the temperature of the power battery is less than 20°C, that is, whether the vehicle system needs waste heat. If not, it is further determined whether the ambient temperature is less than 20°C. If so, the radiator cooling electric drive mode is adopted. Otherwise, the heat pump air conditioning cooling electric drive mode is adopted. If waste heat is needed, it is further determined whether the waste heat available for the electric drive is greater than the heating demand of the battery and the passenger compartment. If not, the electric drive waste heat recovery mode is adopted, that is, the heat pump air conditioning cooling electric drive mode. Otherwise, it is further determined whether the heat storage capacity of the phase change heat accumulator is sufficient. If not, the electric drive waste heat heating and phase change heat accumulator heat storage modes are adopted. Otherwise, the electric drive waste heat heating and radiator cooling electric drive modes are adopted. When the vehicle is parked or turned off, determine whether the ambient temperature is less than 15°C and whether the vehicle will be restarted in a short time. If not, further determine whether the heat stored in the phase change heat accumulator is sufficient. If sufficient, use the radiator heat dissipation mode. Otherwise, use the phase change heat accumulator heat storage mode. If all are satisfied, further determine whether the residual heat of the electric drive and the battery meets the insulation and heating requirements of the battery and the passenger compartment. If not, use the battery and passenger compartment self-insulation mode. Otherwise, further determine whether the heat stored in the phase change heat accumulator is sufficient. If sufficient, use the battery and passenger compartment self-insulation and radiator heat dissipation mode. Otherwise, use the battery and passenger compartment self-insulation and phase change heat accumulator heat storage mode. When the battery starts fast charging, it first determines whether the battery temperature is less than 30°C. If so, the battery self-heating mode is activated. If so, it further determines whether the battery temperature is greater than 40°C. If so, the heat pump air conditioner and radiator are used to cool the battery. Otherwise, the radiator alone is used to cool the battery. When the ambient temperature is monitored to be within 0-5°C and the air humidity is greater than 70%, determine whether the heating efficiency of the heat pump decreases under the same working conditions. If the heating efficiency decreases, start the outdoor heat exchanger defrost mode, and use the heat storage and waste heat auxiliary heating mode to keep the battery and passenger compartment in the optimal temperature area. Otherwise, continue the cycle monitoring.

7. The control method according to claim 6, characterized in that: In a certain mode, the compressor speed, electronic expansion valve opening, and water pump speed are adjusted to optimize the temperature of the passenger compartment and the power battery. Among them, the compressor speed adopts model predictive control, and the electronic expansion valve opening and water pump speed adopt PID control.

8. The control method according to claim 7, characterized in that: The compressor speed adopts model predictive control, specifically: Under different working modes of the vehicle thermal management system, the state quantity and input quantity are selected, and a nonlinear model between the state quantity and control quantity of the air-conditioning system at a certain moment is established. Then, the Taylor series is expanded and only the first-order terms are retained to obtain the approximate linear model of the air-conditioning system. The nonlinear model is subtracted from the approximate linear model and discretized to obtain the discretized state space model of the air-conditioning system: Among them, x(k+1) represents the state of the air conditioning system at the k+1 reference time, A x is the state matrix, x(k) represents the state quantity at discrete time k, B u is the input matrix, u(k) represents the input at discrete time k, y(k) represents the output at time k, and C is the output matrix; The model predictive controller uses the state space model of the air conditioning system to predict the future change trend of the passenger compartment temperature, compares it with the passenger compartment target temperature, and adjusts the compressor speed based on the optimization algorithm; When designing a model predictive controller, the following two goals must be met simultaneously: goal one is to get the expected output value closer to the target value, and goal two is to reduce energy consumption; The objective function of goal one is: Among them, y t (k+i) is the passenger compartment temperature predicted by the air conditioning system state space model, w t (k+i) is the target temperature of the passenger compartment, and P represents the prediction time domain; The objective function of goal 2 is: Wherein, Δu(k) is the rate of change of compressor speed, and M represents the control time domain; The overall objective function of the model predictive controller is: J=J1*ω1+J2*ω2 Among them, ω1 and ω2 are the weight coefficients of target one and target two respectively; By solving the overall objective function, the optimized compressor speed can be obtained to achieve optimal control of the passenger compartment and battery temperature.

9. The control method according to claim 7, characterized in that: The opening of the electronic expansion valve is controlled by PID. Specifically, the electronic expansion valve adjusts the heat exchange amount of the refrigerant in the heat exchanger by controlling the superheat of the system. Based on PID control, the saturated pressure of the refrigerant at the target superheat is used as the target value, the actual pressure at the outlet of the heat exchanger is used as the actual value, and the opening of the electronic expansion valve is used as the control output.

10. The control method according to claim 7, characterized in that: The water pump speed is controlled by PID, specifically: In the battery coolant circulation system, by establishing a heat generation model and heat exchange calculation for the power battery, the current battery temperature change trend is obtained in real time to obtain the actual battery temperature. The difference between the actual battery temperature and the target temperature is used as the input of the PID control, and the speed of the second water pump is used as the output to regulate the coolant flow, thereby achieving a dynamic balance of the battery temperature. In the cooling circulation system of the motor and motor controller, the sensor monitors the actual temperature of the motor water outlet in real time. The controller uses the difference between the target water temperature and the actual water temperature as input, and outputs the third water pump speed to optimize the coolant flow distribution, thereby achieving the optimal balance of energy consumption while meeting the heat dissipation requirements.

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