A thermal management system for a pure electric vehicle based on a shell-and-tube phase-change heat accumulator and a control method thereof

Abstract

The present invention discloses a thermal management system for a pure electric vehicle based on a shell-and-tube phase-change thermal accumulator and its control method. The thermal management system includes a control module, a heat pump air conditioning system, an electric heating and phase-change thermal storage system, a battery thermal management system, and an electric drive cooling system. The control module controls the compressor speed and the opening of the electronic expansion valve to adjust the refrigerant flow rate; the control module controls the speed of each water pump to adjust the coolant flow rate; the control module controls the fan and blower to adjust the air flow rate, 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 coolant, thereby achieving energy coupling between different systems and switching between different operating modes. The present invention achieves energy coupling and integrated management between various systems, meeting thermal management requirements with low energy consumption in multiple scenarios.

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 an important component 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 battery, 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 entire vehicle.

[0003] While current heat pump air conditioning systems reduce energy consumption and improve cooling and heating efficiency, condensation and frost on the exterior radiator reduce heat exchange efficiency with the environment at low temperatures. Heat pump heating efficiency further decreases at temperatures below -10°C. Furthermore, the heat pump air conditioning, power battery, and electric drive thermal management systems are relatively independent, lacking energy coupling and integrated management between these systems. This results in a certain amount of waste heat generated by the battery, motor, electronic control, and other electronic components being 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 requirements with low energy consumption in multiple scenarios, effectively reduce energy consumption and increase mileage. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, 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 circuit, eliminates the need for 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, realizing energy coupling and integrated management between various systems, and meeting 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 includes a compressor, a first four-way valve, an indoor heat exchanger, a first electronic expansion valve, an outdoor heat exchanger, a first one-way valve and a gas-liquid separator 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 one-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; the two ports of the first three-way valve are connected, one of which is connected to a port of the first four-way valve and a port of the first one-way valve respectively through node I, and the other is connected to a port of the second one-way valve and the first heat exchanger respectively through node B;

[0009] The electric heating and phase-change thermal storage system includes a first water pump, a heater core, a heater, a second four-way valve, a shell-and-tube phase-change thermal accumulator, and a third one-way valve, which are connected in sequence; one port of the third one-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; and node C is also connected to the second four-way valve and the shell-and-tube phase-change thermal accumulator.

[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 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 connected in sequence; one port of the third three-way valve is connected to the outdoor radiator and the third water pump respectively through node G.

[0012] The above technical solution also includes a fan and a blower. The fan is installed at the outdoor radiator, and the blower is installed at the indoor heat exchanger. The outdoor heat exchanger and the outdoor radiator are integrated into a design, with the outdoor heat exchanger located on the outside and the outdoor radiator 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 and the battery thermal management system are connected through the first heat exchanger, the heat pump air-conditioning system and the electric drive cooling system are connected through the second heat exchanger, the battery thermal management system and the electric drive cooling system are connected 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 heater 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 comprises: a control module controlling the compressor speed and the opening of an electronic expansion valve to adjust the refrigerant flow; a control module controlling the speed of each water pump to adjust the coolant flow; and a control module controlling the fan and blower to adjust the air flow, controlling the on / off states of each four-way valve, three-way valve, and one-way valve to adjust the refrigerant and coolant circulation circuits, thereby achieving energy coupling between different systems and switching between different operating modes.

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

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

[0018] When the passenger cabin temperature is less than 16°C, it is further determined whether there is waste heat from the battery and electric drive that can be utilized. If so, the heat pump air conditioning and waste heat heating mode are used. If not, it is further determined whether the ambient temperature is less than -15°C. If so, the heat storage and PTC are used to assist the heat pump air conditioning in heating the passenger cabin. Otherwise, the heat storage is used to assist the heat pump air conditioning in heating the passenger cabin. When the passenger cabin temperature is greater than 26°C, the heat pump air conditioning is used to cool the passenger cabin.

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

[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 passenger compartment temperature is less than 16°C or the power battery temperature 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 required, 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, that is, the heat pump air conditioning cooling electric drive mode is adopted. 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, it is determined whether the ambient temperature is less than 15°C and whether the vehicle will be restarted within a short period of time. If not, it is further determined whether the heat stored in the phase change heat accumulator is sufficient. If so, the radiator heat dissipation mode is adopted. Otherwise, the phase change heat accumulator heat storage mode is adopted. If all conditions are met, it is further determined whether the residual heat of the electric drive and battery meets the insulation and heating requirements of the battery and passenger compartment. If not, the battery and passenger compartment self-insulation mode is adopted. Otherwise, it is further determined whether the heat stored in the phase change heat accumulator is sufficient. If so, the battery and passenger compartment self-insulation and radiator heat dissipation mode is adopted. Otherwise, the battery and passenger compartment self-insulation and phase change heat accumulator heat storage mode is adopted.

[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 it is greater than 40°C, 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%, it is determined whether the heat pump heating efficiency decreases under the same working conditions. If the heating efficiency decreases, the outdoor heat exchanger defrost mode is started, and the heat storage and waste heat auxiliary heating mode are used at the same time to keep the battery and passenger compartment in the optimal temperature area. Otherwise, the cycle monitoring continues.

[0024] Furthermore, in a certain mode, the compressor speed, electronic expansion valve opening, and water pump speed are adjusted to optimize the passenger compartment and power battery temperatures. 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 variables and input variables are selected, and a nonlinear model between the state variables and control variables of the air-conditioning system at a certain moment is established. Then, the approximate linear model of the air-conditioning system is obtained by using the Taylor series expansion and retaining only the first-order terms. 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 temperature trend of the passenger compartment, compares it with the target temperature of the passenger compartment, 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 the compressor speed, and M represents the control time domain;

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

[0038] J=J1*ω1+J2*ω2

[0039] Among them, ω1 and ω2 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 adopts PID control, 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 refrigerant saturation pressure at the target superheat is used as the target value, the actual pressure at the heat exchanger outlet 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, and the actual battery temperature is obtained. The difference between the actual battery temperature and the target temperature is used as the input for PID control, and the second water pump speed is used as the output to regulate the coolant flow rate, thereby achieving dynamic balance of 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 includes 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, a first four-way valve, an indoor heat exchanger, a first electronic expansion valve, an outdoor heat exchanger, a first one-way valve, a gas-liquid separator, a second one-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 includes a first water pump, a warm air core, a heater, a second four-way valve, a heat accumulator and a third one-way valve. The battery thermal management system includes a second water pump, a power battery, a third four-way valve and a second three-way valve. The electric drive cooling system includes 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 accumulator heating passenger compartment and battery mode, battery self-insulation (motor waste heat heating battery or heat accumulator 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 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 improve 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, ensuring the reliability of the vehicle's smooth operation, and at the same time placing the outdoor radiator and the outdoor heat exchanger 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 structural diagram 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's operating mode switching logic flow chart based on passenger compartment temperature is shown;

[0051] Figure 3 yes Figure 1 The control module's operating mode switching logic flow chart based on battery temperature is shown;

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

[0053] Figure 5 yes Figure 1 The control module shown is a logic flow chart for utilizing the residual 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 is shown in the heat pump air conditioning mode for heating the passenger compartment in a low-temperature environment;

[0057] Figure 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;

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

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

[0060] Figure 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;

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

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

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

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

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

[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 One-Way Valve, 107-Gas-Liquid Separator, 108-Second One-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 Regenerator, 206-Third One-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 intake 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-heater core first port, 2022-heater 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 one-way valve, 2062-second port of third one-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 - fourth port of the third four-way valve, 3041 - first port of the second three-way valve, 3042 - second port of the second three-way valve, 3043 - third port of the second three-way valve, 3051 - first port of the first heat exchanger, 3052 - second port of the first heat exchanger, 3053 - third port of the first heat exchanger, 3054 - fourth port of the first heat exchanger, 4011 - water outlet of the third water pump, 4012 - water inlet of the third water pump, 4021 - first port of the motor controller, 4022 - second port of the motor controller Port, 4031 - first port of the drive motor, 4032 - second port of the drive motor, 4041 - first port of the third three-way valve, 4042 - second port of the third three-way valve, 4043 - third port of the third three-way valve, 4051 - first port of the second heat exchanger, 4052 - second port of the second heat exchanger, 4053 - third port of the second heat exchanger, 4054 - fourth port of the second heat exchanger, 4061 - first port of the outdoor radiator, 4062 - second port of the 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 This is a structural diagram of the vehicle thermal management system 100 described in the present invention, which includes 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 one-way valve 106, a gas-liquid separator 107, a second one-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 heater core 202, a heater 203, a second four-way valve 204, a shell and tube phase change heat accumulator 205, and a third one-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; and 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 below. The compressor 101 is a scroll type or other type of electric compressor, which is used to evaporate and compress the refrigerant into superheated steam and promote its flow in the refrigerant circulation system. 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 of other types, and can be reasonably replaced as long as they meet the specific connection method. The indoor heat exchanger 103, the outdoor heat exchanger 105, and the outdoor radiator 406 are air-side heat exchangers that provide heat exchange between the air and the refrigerant. When the heat pump air conditioner is cooling, the indoor heat exchanger 103 is the evaporator and the outdoor heat exchanger 105 is the condenser. When the heat pump air conditioner is heating, the indoor heat exchanger 103 is the condenser and the outdoor heat exchanger 105 is the evaporator. 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, which control the valve opening to achieve superheat or subcooling temperature accuracy. 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, controlling the coolant and refrigerant circulation circuits. The gas-liquid separator 107 separates the liquid refrigerant from the gaseous refrigerant in the refrigerant cycle. The water pumps used in the first water pump 201, the second water pump 301, and the third water pump 401 are electric water pumps, which propel the coolant through the coolant circulation system. The heater 203 can be a positive temperature coefficient heater or other type of heater. The first heat exchanger 305 and the second heat exchanger 405 are water-side heat exchangers, providing heat exchange between the coolant and the refrigerant. 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. The fan 501 can be of different types, 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. The blower 502 can be of different types of electric blowers, providing the required air flow for the refrigerant in the indoor heat exchanger 103 and the coolant in the heater core 202 to exchange heat with the air respectively.

[0071] The connecting pipes 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 one-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 one-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 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 3041 of the third one-way valve is connected; 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 further includes a control module 8000. The control module 8000 controls the refrigerant flow by controlling the compressor 101; the control module 8000 controls the coolant flow 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 by controlling the fan 501 and the blower 502; the control module 8000 controls the heating power by controlling the heater 203; and the control module 8000 regulates the refrigerant and coolant circulation circuits by controlling the on / off states 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 one-way valve 106, the second one-way valve 108, the third one-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 passenger compartment temperature, battery temperature and electric drive water outlet temperature, 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 for 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 If the temperature is not less than 16℃, further determine whether the ambient temperature is less than 20℃. If so, adopt the radiator cooling battery mode. Otherwise, adopt the heat pump air conditioning cooling 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 passenger compartment heating demand. If not, adopt the battery waste heat to heat the passenger compartment, that is, the heat pump air conditioning cooling battery mode. Otherwise, further determine whether the heat storage capacity of the phase change heat accumulator is sufficient. If not, adopt the battery waste heat to heat the passenger compartment and the heat accumulator heat storage mode. Otherwise, adopt the battery waste heat to heat the passenger compartment and the radiator cooling battery mode.

[0076] Figure 4 yes Figure 1 The control module shown in the figure has a logic flow chart for switching 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℃, the motor self-insulation mode is started; when the temperature of the electric drive system is greater than 60℃, it is further judged whether the passenger compartment temperature is less than 16℃ or the power battery temperature is less than 20℃, that is, whether the entire vehicle system requires waste heat. If not, it is further judged whether the ambient temperature is less than 20℃. 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 judged 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, that is, the heat pump air conditioning cooling electric drive mode, is adopted. Otherwise, it is further judged 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 residual heat of the 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 charge 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. Therefore, it is first determined whether the battery temperature is less than 30°C. If so, the battery self-insulation mode is activated and the battery is not cooled. Otherwise, it is further determined whether the battery temperature is greater than 40°C. If so, the heat pump air conditioning and radiator cooling battery mode are used. Otherwise, the radiator alone is used 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 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 conditions. If the heating efficiency decreases, the defrost mode of the outdoor heat exchanger 105 is started, and the heat storage 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 achieve the best 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 passenger compartment, power battery and electric drive temperatures. The control methods of the compressor speed, electronic expansion valve opening and water pump speed will be detailed below.

[0081] The heat pump air conditioning system for pure electric vehicles uses model predictive control to regulate compressor speed. The effectiveness of model predictive controllers relies on accurate mathematical models. However, air conditioning systems exhibit dynamic nonlinearity, coupled nature, and multiple inputs and multiple outputs. Simply adjusting the compressor speed is not sufficient to achieve the target passenger compartment temperature. The coupling effects of other variables must be considered. Therefore, a state-space model is needed to comprehensively describe the system's dynamic behavior. This provides a foundation for the model predictive controller, which is used to predict future states and optimize control inputs, thereby achieving comprehensive optimization of system performance, stability, and energy consumption.

[0082] Based on this, the compressor speed controlled by the model predictive controller is used as one of the input variables u(k) of the air conditioning system's state-space model. The passenger compartment temperature (so C is the identity matrix in this case), one of the output variables y(k) of the air conditioning system's state-space model, is fed back as a measurable input to the model predictive controller. The model predictive controller uses the air conditioning system's state-space model to predict the future trend of the passenger compartment temperature, compares it with the target passenger compartment temperature, and adjusts the compressor speed based on an optimization algorithm. The adjusted compressor speed is then fed back into the state-space model as a new input, and the prediction and optimization process is iterated.

[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 retaining the first-order terms 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), subtracting equation (1) from equation (2) to obtain 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 take into account both 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] Equation (6) is the linear system at a certain reference point obtained after the nonlinear system is linearized.

[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 operating in cooling mode, the passenger compartment 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 passenger compartment 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 identity 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] The first goal is to get the expected output value close to the target value. 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 output.

[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 horizon, which is the number of future time steps that 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=J1*ω1+J2*ω2(10)

[0114] Among them, ω1 and ω2 are the weight coefficients of target one and target two respectively.

[0115] The choice of weighting coefficients ω1 and ω2 depends on the operating priority: ω1 is weighted more when ensuring passenger comfort, while ω2 is weighted more when prioritizing energy efficiency. Based on the actual operating conditions, the weighting coefficients can be adaptively adjusted to achieve a balance. By solving the overall objective function, the optimized compressor speed is obtained, thereby achieving the optimal control targets for passenger compartment and battery temperature.

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

[0117]

[0118] Where Δu max is the maximum compressor speed change rate; u(k) is the compressor speed, u min 、u maxThey 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 transmits 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). 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 regulates the amount of heat transferred by the refrigerant in the heat exchanger by controlling the system's superheat. Based on a PID algorithm, the refrigerant's saturated pressure at the target superheat is used as the target value, the actual pressure at the heat exchanger outlet is used as the actual value, and the electronic expansion valve opening is used as the control output.

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

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

[0126]

[0127] Where q is the heat generation power per unit volume of the lithium battery; I is the battery discharge current during vehicle driving; V is the volume of the lithium battery cell; 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 due to the convection heat exchange between the coolant and the battery through the cooling plate, which is calculated using Newton's formula:

[0129] Q=μA bat (T bat -T l )(15)

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

[0131] By using the power battery heat generation model and Newton's heat transfer formula, the current battery temperature trend can be obtained in real time, thereby determining 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 dynamic balance of battery temperature.

[0132] In the cooling circulation system between the motor and motor controller, sensors monitor the actual temperature of the motor's water outlet in real time. The controller uses the difference between the target and actual water temperatures as input and outputs the third water pump speed, which optimizes coolant flow distribution to achieve the optimal balance between cooling requirements and energy consumption.

[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 represent the flow direction and flow path of the refrigerant, the bold solid arrows represent the flow direction and flow path of the coolant, and the other solid lines represent 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 a passenger compartment heating instruction (or the control module 8000 automatically generates a 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, high-pressure vapor refrigerant. It flows out of 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 pipe 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 action of condensation, 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, high-pressure liquid refrigerant passes through the pipe node E to the first electronic expansion valve 104, where it is reduced in pressure and increases in volume, becoming a low-temperature, low-pressure liquid mist refrigerant. It then passes through the pipe node H It flows to 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 and become 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, starting the next refrigerant cycle.

[0135] Figure 9 for Figure 1The following diagram shows the vehicle thermal management system in heat pump air conditioning and battery heating mode in a low-temperature environment. In low-temperature environments, when the battery temperature falls below the appropriate operating temperature and the heat storage device is insufficiently heated, the control module 8000 generates a battery heating command. Upon receiving the battery heating command, the vehicle thermal management system 100 transfers heat to the battery in heat pump air conditioning and battery heating 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 vapor 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. At this time, the first heat exchanger 305 acts as a condenser. Under the action of condensation, 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 reduced in pressure and increase in volume, becoming a low-temperature and low-pressure liquid mist refrigerant, and then flows through the pipeline node H. Towards 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, starting the next refrigerant cycle. On the other side, 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. After absorbing the heat released by the refrigerant and becoming high-temperature coolant, it 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] Figure 10 for Figure 1The following diagram shows the vehicle thermal management system in low-temperature ambient temperature mode, using the heater and heat accumulator to heat the passenger compartment and battery. In low-temperature environments, when the heat accumulator has sufficient heat, the battery temperature is below the appropriate operating temperature, and the passenger compartment requires heating, the control module 8000 generates battery and passenger compartment heating instructions. Upon receiving these instructions, the vehicle thermal management system 100 transfers heat to the battery and passenger compartment using the heater and heat accumulator in this heating mode. 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. Then, it 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 from 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 enters the shell and tube phase change heat accumulator 205. After the fourth port 2044 and the first port 2041 of the valve are opened, the coolant 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, so that the temperature of the entire passenger compartment rises evenly. 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 coolant can be auxiliary heated by the heater 203 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 water inlet 3012 of the second water pump in turn, and then reaches the second water pump 301 to start the next coolant cycle.

[0137] Figure 11 for Figure 1The following diagram shows the vehicle's thermal management system in battery self-insulation mode in a low-temperature environment. In low-temperature environments, when a vehicle is briefly parked, additional battery heating is required to prevent the battery from freezing during restart. This utilizes waste heat recovered from the electric drive and heat stored in the heat accumulator to maintain battery temperature 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. Then it 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 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 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 third three-way valve 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 phase change heat accumulator to the shell and tube 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 phase change heat accumulator 205. When the residual heat is excessive, the shell and tube phase change heat accumulator 205 absorbs the residual heat. After that, the coolant flows out from the first port 2051 of the shell and tube 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] Figure 12 for Figure 1The following diagram shows the vehicle's thermal management system in waste heat recovery mode for the battery and electric drive in low-temperature environments. When the vehicle stops and won't be restarted for a short time, waste heat from the battery and electric drive needs to be recovered. Alternatively, after a period of driving in low-temperature environments, the battery and electric drive become overheated and require cooling. Heat pump air conditioners have low heating efficiency at low temperatures, making it difficult to absorb heat from the outside air. Therefore, heat is absorbed from the battery and electric drive, improving both the heat pump's heating efficiency and cooling 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. 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 action of condensation, 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 is discharged from the second electronic expansion valve 111. Liquid flows out of the expansion valve 111 to the third port 4053 of the second heat exchanger, then enters the second heat exchanger 405, where it absorbs heat from the coolant and evaporates into a low-temperature, low-pressure gas-liquid mixture. At this point, the second heat exchanger acts as an evaporator. The refrigerant then flows out of the fourth port 4054 of the second heat exchanger, passing through the second and first ports of the first three-way valve, pipeline node I, the fourth port 1024 of the first four-way valve, and the third port 1023, before reaching the gas-liquid separator inlet 1072. After passing through the gas-liquid separator 107, where the liquid and gaseous refrigerant are separated, the liquid refrigerant remains in the gas-liquid separator 107, while the gaseous refrigerant enters the compressor 101 through the compressor inlet 1012, beginning the next refrigerant cycle. The coolant circulation in this mode is identical to that in the battery self-insulation mode described above and will not be further described here.

[0139] Figure 13 for Figure 1The following diagram shows the vehicle's thermal management system in outdoor heat exchanger defrost mode in low-temperature environments. In low-temperature environments, the outdoor heat exchanger frequently defrosts, reducing the heating efficiency of the heat pump air conditioner and necessitating defrosting. To ensure thermal comfort in the passenger compartment at low temperatures, the cabin is heated using waste heat from the battery and motor, as well as stored heat from the heat accumulator. 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, and then flows through the pipeline node I and the first one-way valve 106 to the refrigerant channel of the outdoor heat exchanger 105. At this time, the outdoor heat exchanger 105 acts as a condenser. Under the action of condensation, the refrigerant liquefies and releases heat, heating the fins of the outdoor heat exchanger 105, so that the frost on the surface of the fins melts. 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 coolant enters the second heat exchanger 405 at the third port 4053, where it absorbs the heat released by the coolant and becomes a low-temperature, low-pressure gas-liquid mixture. It then flows out of the second heat exchanger 4054, passing through the second and third ports 1102 and 1103 of the first three-way valve, pipe intersection B, the second one-way valve 108, pipe intersection A, the second and third ports 1022 and 1023 of the first four-way valve, and finally reaches the gas-liquid separator inlet 1072. After passing through the gas-liquid separator 107, where the liquid and gaseous refrigerant are separated, the liquid refrigerant remains in the gas-liquid separator 107, while the gaseous refrigerant enters the compressor 101 through the compressor inlet 1012, beginning the next refrigerant cycle. The coolant circulation in this mode combines the aforementioned heater and heat accumulator heating mode and the battery self-insulation mode, and will not be further described here.

[0140] Figure 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 temperature of the battery and electric drive will be too high and need to be dissipated 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 through the pipeline node I and the first one-way valve 106 to the refrigerant channel of the outdoor heat exchanger 105. 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 and reaches the third electronic expansion valve 104. It will reduce pressure and increase 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 into 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, 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, starting 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 from 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 inside 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 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 refrigerant flows through 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, to the second port 3052 of the first heat exchanger, enters the first heat exchanger 305, releases 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 water inlet 3012 of the second water pump in sequence, and then enters the second water pump 301, starting the next coolant cycle.

[0141] Figure 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 instruction (or the control module 8000 automatically generates the passenger compartment cooling instruction). 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, 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 action of condensation, the refrigerant is liquefied 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 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 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. Then, it 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, starting the next refrigerant cycle.

[0142] Figure 16 for Figure 1The figure shows the vehicle's thermal management system in super-cooling mode during rapid charging. During rapid charging, especially in hot summer weather, the battery is prone to overheating, so super-cooling mode is needed to quickly cool the battery and 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 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. Under the action of condensation, 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 be decompressed and increase in volume when it reaches the first electronic expansion valve 104, becoming a low-temperature and low-pressure liquid mist refrigerant), and flows through the pipeline node E to the 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 whole The temperature of the entire passenger compartment drops evenly, turning into a low-temperature, low-pressure gas-liquid mixture. The mixture then flows to pipeline node A and branch 2 (the refrigerant is decompressed and expanded in volume at the third electronic expansion valve 109, turning into a low-temperature, low-pressure liquid mist refrigerant. The mixture then flows to the fourth port 3054 of the first heat exchanger and enters the first heat exchanger 305, where it absorbs heat from the coolant and evaporates into a low-temperature, low-pressure gas-liquid mixture. The mixture then flows out of the third port 3053 of the first heat exchanger, passes through pipeline intersection B and the second one-way valve 108, and flows to pipeline node A. The mixture then converges at pipeline node A, 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 liquid and gas 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 through the compressor inlet 1012, beginning the next refrigerant cycle.On the other side, 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 refrigerant is metered, and 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 water inlet 3012 of the second water pump in sequence, and then enters the second water pump 301, starting the next coolant cycle.

[0143] Figure 17 for Figure 1 The following diagram shows the vehicle's thermal management system in a high-temperature environment with a heat pump air conditioner providing enhanced cooling for the battery and electric drive. In high-temperature environments, the battery and electric drive are prone to overheating, necessitating rapid heat dissipation. Simultaneously, the passenger compartment requires cooling. To this end, the two heat exchangers in the heat pump air conditioner cycle and the outdoor radiator are simultaneously activated to cool the passenger compartment, battery, and electric drive. The refrigerant cycle in this mode combines the heat pump air conditioner's passenger compartment cooling mode with the battery's super-cooling mode. The coolant cycle is identical to that in the heat pump air conditioner's battery and electric drive mode and is not further detailed here.

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

Claims

1. A thermal management system for a pure electric vehicle based on a shell and tube phase change thermal accumulator, 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 one-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 one-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 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 one-way valve (106) through node I, and the other of which is connected to a port of the second one-way valve (108) and the first heat exchanger (305) through 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 node C and one port of the second three-way valve (304) through 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 further comprises 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, it blows air 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 one-way valve (106), the second one-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 one-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 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 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: Switching between different working modes: Determine whether the vehicle is in the starting state. When the vehicle is started, monitor the passenger compartment temperature, battery temperature, and electric drive water outlet temperature; When the passenger cabin temperature is less than 16°C, it is further determined whether there is waste heat from the battery and electric drive that can be utilized. If so, the heat pump air conditioning and waste heat heating mode are used. If not, it is further determined whether the ambient temperature is less than -15°C. If so, the heat storage and PTC are used to assist the heat pump air conditioning in heating the passenger cabin. Otherwise, the heat storage is used to assist the heat pump air conditioning in heating the passenger cabin. When the passenger cabin temperature is greater than 26°C, the heat pump air conditioning is used to cool the passenger cabin. When the power battery temperature is less than 20°C, it is further determined whether there is any electric drive waste heat that can be utilized. If so, the electric drive waste heat is used to assist the heat pump air conditioner to heat the battery. 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. Otherwise, the heat storage device is used to assist the heat pump to heat the battery. When the power battery temperature is greater than 30°C, it is further determined whether the passenger compartment temperature is not less than 16°C. If the ambient temperature is less than 20°C, the radiator is used to cool the battery. Otherwise, the heat pump air conditioner is used to cool the battery. If the passenger compartment temperature is less than 16°C, it is further determined whether the battery's available waste heat is greater than the passenger compartment heating demand. If not, the battery waste heat is used to heat the passenger compartment, that is, the heat pump air conditioner is used to cool the battery. Otherwise, it is further determined whether the phase change heat storage device has sufficient heat. If not, the battery waste heat is used to heat the passenger compartment and the heat storage device is used. Otherwise, the battery waste heat is used to heat the passenger compartment and the radiator is used to cool the battery. 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 passenger compartment temperature is less than 16°C or the power battery temperature 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 required, 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, that is, the heat pump air conditioning cooling electric drive mode is adopted. 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, it is determined whether the ambient temperature is less than 15°C and whether the vehicle will be restarted within a short period of time. If not, it is further determined whether the heat stored in the phase change heat accumulator is sufficient. If so, the radiator heat dissipation mode is adopted. Otherwise, the phase change heat accumulator heat storage mode is adopted. If all conditions are met, it is further determined whether the residual heat of the electric drive and battery meets the insulation and heating requirements of the battery and passenger compartment. If not, the battery and passenger compartment self-insulation mode is adopted. Otherwise, it is further determined whether the heat stored in the phase change heat accumulator is sufficient. If so, the battery and passenger compartment self-insulation and radiator heat dissipation mode is adopted. Otherwise, the battery and passenger compartment self-insulation and phase change heat accumulator heat storage mode is adopted. 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 it is greater than 40°C, 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%, it is determined whether the heat pump heating efficiency decreases under the same working conditions. If the heating efficiency decreases, the outdoor heat exchanger defrost mode is started, and the heat storage and waste heat auxiliary heating mode are used at the same time to keep the battery and passenger compartment in the optimal temperature area. Otherwise, the cycle monitoring continues.

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 passenger compartment and power battery temperatures. 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 variables and input variables are selected, and a nonlinear model between the state variables and control variables of the air-conditioning system at a certain moment is established. Then, the approximate linear model of the air-conditioning system is obtained by using the Taylor series expansion and retaining only the first-order terms. 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 temperature trend of the passenger compartment, compares it with the target temperature of the passenger compartment, 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 the 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 heat exchanger outlet 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, and the actual battery temperature is obtained. The difference between the actual battery temperature and the target temperature is used as the input for PID control, and the second water pump speed is used as the output to regulate the coolant flow rate, thereby achieving dynamic balance of 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.

Images