Pure electric vehicle integrated heat management system and method based on heat pump air conditioner

Abstract

The invention relates to the technical field of electric vehicle lithium battery thermal management, and particularly discloses a pure electric vehicle integrated thermal management control system and method based on a heat pump air conditioner. Information such as states of a cab thermal management subsystem and a battery system thermal management subsystem, drivers, external environment information, component working states and cooling liquid temperature is obtained, a whole vehicle thermal management mode is judged, working modes of the subsystems are determined, different valves and water pumps are controlled to be opened, heating equipment and refrigeration equipment are controlled, and the control system is controlled. Different conduction modes of the pipeline connecting pieces are set, different modes in the three subsystems are controlled to be combined with one another, and control over the whole vehicle thermal management system is achieved; the rotating speed of the compressor and the refrigerating capacity of the system are controlled through the sliding mode variable structure model; and the EXV opening degree of the electronic expansion valve and the gear of the PTC heater are controlled through a PID algorithm, so that the power battery is in an efficient and safe working temperature, and the energy consumption of the vehicle is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management of lithium batteries for electric vehicles, and in particular to an integrated thermal management system and method for pure electric vehicles based on a heat pump air conditioner. Background Art

[0002] As energy and environmental issues become increasingly serious, electric vehicles have become a means of transportation that is increasingly accepted by people. At the same time, lithium-ion batteries are used in electric vehicles because of their longer cycle life and higher energy density. However, the performance of lithium-ion power batteries is greatly affected by temperature. Too high a temperature will affect its performance and even safety, while too low a temperature will affect the battery life. Therefore, a good battery thermal management system is of great significance in extending battery life and improving battery performance.

[0003] Among all the accessories of pure electric vehicles, the air-conditioning system consumes the most power. Since the engine is cancelled, pure electric vehicles usually use PTC heaters for low-temperature heating, making the heating method in winter a major problem affecting the endurance of pure electric vehicles. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems mentioned above, and provides an integrated thermal management system and method for pure electric vehicles based on heat pump air conditioning, which can ensure that the battery pack is in the optimal operating temperature range, solve the problems of high vehicle energy consumption and low efficiency of the thermal management system when the vehicle is heated at low temperature, and adopt thermal management modes under different working conditions to increase the vehicle's cruising range and protect battery life and vehicle safety.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a pure electric vehicle integrated thermal management system based on heat pump air conditioning, including a compressor, an outdoor heat exchanger, an evaporator, an indoor heat exchanger, a battery liquid cooling plate, a cooler, a valve mechanism, a first water pump, a second water pump, a motor liquid cooling plate, an electronically controlled liquid cooling plate, a warm air water tank, a low-temperature water tank, a PTC heater, a gas-liquid separator, a fan and a blower, the valve mechanism includes a first three-way valve, a second three-way valve, a third three-way valve, a fourth three-way valve, a fifth three-way valve, a sixth three-way valve, a seventh three-way valve, a first electronic expansion valve, a second electronic expansion valve, and a third electronic expansion valve, wherein:

[0006] The outlet of the gas-liquid separator is connected to the air inlet of the compressor, the exhaust port of the compressor is connected to the first three-way valve, the outdoor heat exchanger, the second three-way valve, and the evaporator in sequence, the cooler and the third electronic expansion valve are connected in series and connected to the second three-way valve, the indoor heat exchanger and the first electronic expansion valve are connected in series and arranged between the first three-way valve and the second three-way valve to form a heat pump air conditioning circulation loop;

[0007] The first water pump is connected in series with the cooler, the battery liquid cooling plate, and the sixth three-way valve in sequence, the water inlet of the second water pump is connected to the low-temperature water tank, the water outlet of the second water pump is connected in series with the first end and the second end of the third three-way valve, the motor liquid cooling plate, the electronic control liquid cooling plate, the first end and the second end of the fourth three-way valve, the warm air heat exchanger, the first end and the second end of the seventh three-way valve, the battery liquid cooling plate, the second end and the third end of the sixth three-way valve, and the second end and the third end of the fifth three-way valve in sequence, and the third end of the third three-way valve is connected in series with the PTC heater, the first end and the third end of the fourth three-way valve, the second end and the third end of the seventh three-way valve, the first end and the third end of the fifth three-way valve, and the low-temperature water tank in sequence to form a battery coolant circulation loop.

[0008] Preferably, heat is exchanged between the heat pump air conditioning circulation loop and the battery coolant circulation loop through a cooler, and the cooler includes a fan and a blower, wherein the fan provides the required air flow for heat exchange between the outdoor radiator refrigerant and the air, and the blower provides the required air flow for heat exchange between the heater water tank coolant and the air.

[0009] Preferably, the integrated thermal management system includes a cab thermal management subsystem, a battery thermal management subsystem, and a motor / electronic control thermal management subsystem.

[0010] Preferably, the cab thermal management subsystem includes an air conditioning cooling mode, a heat pump heating mode, a PTC heating mode and a motor / electronic control waste heat recovery heating mode.

[0011] Preferably, the battery thermal management subsystem includes a battery balancing mode, a battery waste heat recovery heating mode, a battery PTC heating mode, a battery low-temperature water tank cooling mode, and a battery air-conditioning circulation cooling mode.

[0012] Preferably, the motor / electrical control thermal management subsystem includes a motor / electrical control low-temperature water tank refrigeration mode.

[0013] The present application also discloses a pure electric vehicle integrated thermal management method based on a heat pump air conditioner, using any of the above-mentioned integrated thermal management systems, when the system is started, it is initialized and the cab air conditioning temperature T is set. cs ;

[0014] According to the vehicle sensor, obtain the ambient temperature T e , Cabin temperature T c , average battery pack temperature T b , Electric / electronically controlled outlet coolant temperature T m , compressor speedω c 、Motor speedω m data;

[0015] According to the different temperature requirements of each subsystem, determine the thermal management mode of each subsystem, control the opening and closing of the valve, and control the heating and cooling equipment; switch the mode according to the average temperature change of the battery pack and the temperature change of the cab, among which,

[0016] The determination of the cab thermal management system mode includes:

[0017] If the cab temperature is higher than the cab air conditioning setting temperature, the air conditioning cooling mode is used;

[0018] If the cab temperature is slightly lower than the cab air conditioning setting temperature, and the electric / electronically controlled outlet coolant temperature is greater than the waste heat recovery threshold temperature, the motor / electronically controlled waste heat recovery heating mode is used;

[0019] If the cab temperature is lower than the cab air conditioning setting temperature and the ambient temperature is higher than the heat pump start-up temperature, the heat pump air conditioning heating mode is used;

[0020] If the cab temperature is lower than the cab air conditioning setting temperature, the ambient temperature is lower than the heat pump start-up temperature, or when rapid heating is required, the PTC heating mode is used.

[0021] The determination of the battery thermal management system mode includes:

[0022] If the average temperature of the battery pack is greater than the upper limit of the optimal temperature of the battery pack and less than the warning temperature, the low-temperature water tank cooling mode is adopted;

[0023] If the average temperature of the battery pack is greater than the upper limit of the optimal temperature of the battery pack and greater than the warning temperature, the air conditioning cooling mode is used;

[0024] If the average temperature of the battery pack is lower than the lower limit of the optimal temperature of the battery pack and the coolant temperature at the electric / electronically controlled outlet is higher than the waste heat recovery threshold temperature, the battery waste heat recovery heating mode is adopted;

[0025] If the average temperature of the battery pack is lower than the lower limit of the optimal temperature of the battery pack and the ambient temperature is lower than the start-up temperature of the heat pump, the PTC heating mode is used.

[0026] Preferably, after the subsystem modes are integrated, the priority of each subsystem is established, including: giving priority to the temperature of the cab subsystem, and after the system adjusts the cab temperature to a temperature value acceptable to the human body, adjusting it with the battery subsystem temperature control as the core.

[0027] Preferably, based on the analysis of the heat load of the cab and the battery system, a sliding mode variable structure control model is constructed, which is expressed as:

[0028] ω c =(e1-e2)+asgns+ks

[0029] Wherein, e1 represents the deviation between the system set temperature and the actual temperature, e2 represents the rate of change of the deviation between the system set temperature and the actual temperature, sgns represents the sign function, and k is the system gain;

[0030] Construct constraints, and determine the optimal controller parameters of the sliding mode controller based on the optimization algorithm with the minimum constraint value as the optimization goal to obtain the sliding mode controller. The expression of the constraint condition is:

[0031]

[0032] Where J is the error value, t is the time, τ is the integral intermediate variable of time t, T b is the battery pack temperature, T bs is the preset battery pack temperature, q is a constant, and the compressor speed is controlled by the system temperature difference to control the system cooling capacity.

[0033] Preferably, the opening of the electronic expansion valve EXV and the PTC gear position are controlled by PID according to the compressor speed, the battery water inlet temperature, the cab temperature, and the air-conditioning set temperature.

[0034] The beneficial effect is that compared with the prior art, the integrated thermal management system and method of a pure electric vehicle based on a heat pump air conditioner of the present invention has the following advantages:

[0035] 1. Faced with different working conditions, each subsystem can adopt appropriate working modes to achieve different thermal management functions;

[0036] 2. Adopting an integrated thermal management system based on heat pump air conditioning simplifies the system volume and makes it easier to control;

[0037] 3. Use electronic control and motor waste heat to heat the battery and make full use of the heat;

[0038] 4. Adopt the "PTC+heat pump system" hybrid heating solution to improve utilization and reduce vehicle energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0040] Figure 1 A schematic diagram of an integrated thermal management system for a pure electric vehicle based on a heat pump air conditioner according to an embodiment;

[0041] Figure 2 A schematic diagram of air conditioning and refrigeration of a cab thermal management subsystem according to an embodiment;

[0042] Figure 3 It is a schematic diagram of the cooling mode of the air conditioning system and the cooling mode of the battery low-temperature water tank;

[0043] Figure 4 It is a schematic diagram of air conditioning cooling mode, battery air conditioning cooling mode and motor / electrically controlled low-temperature water tank cooling mode;

[0044] Figure 5 This is a schematic diagram of the heat pump heating mode;

[0045] Figure 6 Schematic diagram of heat pump heating mode, battery waste heat recovery heating mode and motor / electronic control waste heat recovery heating mode;

[0046] Figure 7 Schematic diagram of PTC heating mode and battery PTC heating mode;

[0047] Figure 8 A control flow chart of a management method using an integrated thermal management system.

[0048] In the figure:

[0049] 1- compressor, 2- outdoor heat exchanger, 3- indoor heat exchanger, 4- evaporator, 5- battery pack liquid cooling plate, 6- cooler, 701- first three-way valve, 702- second three-way valve, 703- third three-way valve, 704- fourth three-way valve, 705- fifth three-way valve, 706- sixth three-way valve, 707- seventh three-way valve, 801- first electronic expansion valve EXV, 802- second electronic expansion valve EXV, 803- third electronic expansion valve EXV, 9- first water pump, 10- second water pump, 11- motor liquid cooling plate, 12- electronically controlled liquid cooling plate, 13- warm air tank, 14- low temperature tank, 15- PTC heater, 16- gas-liquid separator, 17- blower, 18- fan, 19- cab. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is referred to as being "set in the middle", it does not only mean being set in the middle, as long as it is not set at both ends within the range defined by the middle. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0053] like Figure 1 As shown, the present application discloses a pure electric vehicle integrated thermal management system based on a heat pump air conditioner, including a compressor, an outdoor heat exchanger, an evaporator, an indoor heat exchanger, a battery liquid cooling plate, a cooler, a valve mechanism, a first water pump, a second water pump, a motor liquid cooling plate, an electronically controlled liquid cooling plate, a warm air water tank, a low temperature water tank, a PTC heater, a gas-liquid separator, a fan and a blower, and the valve mechanism includes a first three-way valve, a second three-way valve, a third three-way valve, a fourth three-way valve, a fifth three-way valve, a sixth three-way valve, a seventh three-way valve, a first electronic expansion valve, a second electronic expansion valve, and a third electronic expansion valve, wherein:

[0054] The outlet of the gas-liquid separator is connected to the air inlet of the compressor, the exhaust port of the compressor is connected to the first three-way valve, the outdoor heat exchanger, the second three-way valve, and the evaporator in sequence, the cooler and the third electronic expansion valve are connected in series and connected to the second three-way valve, the indoor heat exchanger and the first electronic expansion valve are connected in series and arranged between the first three-way valve and the second three-way valve to form a heat pump air conditioning circulation loop;

[0055] The first water pump is connected in series with the cooler, the battery liquid cooling plate, and the sixth three-way valve in sequence, the water inlet of the second water pump is connected to the low-temperature water tank, the water outlet of the second water pump is connected in series with the first end and the second end of the third three-way valve, the motor liquid cooling plate, the electronic control liquid cooling plate, the first end and the second end of the fourth three-way valve, the warm air heat exchanger, the first end and the second end of the seventh three-way valve, the battery liquid cooling plate, the second end and the third end of the sixth three-way valve, and the second end and the third end of the fifth three-way valve in sequence, and the third end of the third three-way valve is connected in series with the PTC heater, the first end and the third end of the fourth three-way valve, the second end and the third end of the seventh three-way valve, the first end and the third end of the fifth three-way valve, and the low-temperature water tank in sequence to form a battery coolant circulation loop.

[0056] Heat is exchanged between the heat pump air conditioning circulation loop and the battery coolant circulation loop through a cooler, which includes a fan and a blower. The fan provides the required air flow for heat exchange between the outdoor radiator refrigerant and the air, and the blower provides the required air flow for heat exchange between the heater water tank coolant and the air.

[0057] The integrated thermal management system includes the cab thermal management subsystem, battery thermal management subsystem, and motor / electronic control thermal management subsystem. Specifically:

[0058] The cab thermal management subsystem includes air conditioning cooling mode, heat pump heating mode, PTC heating mode and motor / electronic control waste heat recovery heating mode.

[0059] The air conditioning refrigeration mode includes: a compressor, a three-way valve, an outdoor heat exchanger, a second electronic expansion valve, an evaporator, and a gas-liquid separator; the first end and the second end of the first three-way valve are connected, the first end and the second end of the second three-way valve are connected, and the second electronic expansion valve is opened; the refrigerant flows through the compressor, the outdoor heat exchanger, the second electronic expansion valve, and the evaporator to cool the cab;

[0060] The heat pump heating mode includes: a compressor, a three-way valve, an indoor heat exchanger, a first electronic expansion valve, an outdoor heat exchanger, and a gas-liquid separator; the first end of the first three-way valve is connected to the third end, and the first electronic expansion valve is opened; the refrigerant flows through the compressor, the indoor heat exchanger, the first electronic expansion valve, and the outdoor heat exchanger to heat the cab;

[0061] The PTC heating mode includes: a second water pump, a PTC heater, a heater water tank and a fan; the first end and the third end of the third three-way valve are connected, the first end and the second end of the fourth three-way valve are connected, the second end and the third end of the seventh three-way valve are connected, and the second end and the third end of the fifth three-way valve are connected; the coolant flows through the water pump, the PTC heater, and the heater water tank in sequence to heat the cab;

[0062] The motor / electronic control waste heat recovery heating mode includes: a second water pump, a motor liquid cooling plate, an electronic control liquid cooling plate and a warm air water tank; the first end and the second end of the third three-way valve are connected, the first end and the second end of the fourth three-way valve are connected, the second end and the third end of the seventh three-way valve are connected, and the second end and the third end of the fifth three-way valve are connected; the coolant flows through the water pump, the motor liquid cooling plate, the electronic control liquid cooling plate and the warm air water tank in sequence to heat the cab.

[0063] The battery thermal management subsystem includes battery waste heat recovery heating mode, battery PTC heating mode, battery low-temperature water tank cooling mode, and battery air-conditioning circulation cooling mode.

[0064] The battery balancing mode includes: a water pump, a battery liquid cooling plate, and a cooler; the first end and the second end of the sixth three-way valve are connected; the coolant flows through the water pump, the cooler, and the battery liquid cooling plate in sequence, so that the temperature between the battery cells is kept balanced;

[0065] The battery air conditioning cycle refrigeration mode includes: a compressor, a three-way valve, an outdoor heat exchanger, a third electronic expansion valve, a cooler, a gas-liquid separator, a water pump and a battery liquid cooling plate; the first end of the first three-way valve is connected to the second end, the first end of the second three-way valve is connected to the third end, the first end of the fifth three-way valve is connected to the second end, and the third electronic expansion valve is opened; the refrigerant flows through the compressor, the outdoor heat exchanger, the third electronic expansion valve, and the cooler; at the same time, the coolant flows through the water pump and the cooler in sequence, and heat is exchanged at the cooler, and the battery is cooled by the air conditioning system;

[0066] The battery low-temperature water tank cooling mode includes: a water pump, a battery liquid cooling plate, and a low-temperature water tank; the first end and the third end of the third three-way valve are connected, the first end and the third end of the fourth three-way valve are connected, the first end and the third end of the seventh three-way valve are connected, the second end and the third end of the sixth three-way valve are connected, and the first end and the third end of the fifth three-way valve are connected; the coolant flows through the water pump, the battery liquid cooling plate, and the low-temperature water tank in sequence;

[0067] The battery PTC heating mode includes: a second water pump, a PTC heater, and a battery liquid cooling plate; the first end and the third end of the third three-way valve are connected, the first end and the third end of the fourth three-way valve are connected, the first end and the second end of the seventh three-way valve, the second end and the third end of the sixth three-way valve are connected, and the second end and the third end of the fifth three-way valve are connected; the coolant flows through the water pump, the PTC heater, and the battery liquid cooling plate in sequence to heat the battery;

[0068] The battery waste heat recovery mode includes: water pump, motor liquid cooling plate, electronic control liquid cooling plate, battery liquid cooling plate; the first end and the second end of the third three-way valve are connected, the first end and the third end of the fourth three-way valve are connected, the first end and the second end of the seventh three-way valve are connected, the second end and the third end of the sixth three-way valve are connected, and the second end and the third end of the fifth three-way valve are connected; the coolant flows through the water pump, the motor liquid cooling plate, the electronic control liquid cooling plate, and the battery liquid cooling plate in sequence to heat the battery.

[0069] The motor / electronic control thermal management subsystem includes a motor / electronic control low-temperature water tank cooling mode, which includes: a second water pump, a motor liquid cooling plate, an electronic control liquid cooling plate, and a low-temperature water tank; the first end and the second end of the third three-way valve are connected, the first end and the third end of the fourth three-way valve are connected, the second end and the third end of the seventh three-way valve are connected, and the second end and the third end of the fifth three-way valve are connected; the coolant flows through the water pump, the motor liquid cooling plate, the electronic control liquid cooling plate, and the low-temperature water tank in sequence.

[0070] The following is an introduction to the above working modes in combination with some specific working states. Figure 2 As shown, if the cab temperature is higher than the cab air conditioning setting temperature, the average temperature of the battery pack is in the optimal temperature range, and the air conditioning cooling mode and the battery balancing mode are adopted, then one end and the second end of the first three-way valve are connected, the first end and the second end of the second three-way valve are connected, and the second electronic expansion valve is opened; the refrigerant flows through the compressor, the outdoor heat exchanger, the second electronic expansion valve, and the evaporator, and returns to the gas-liquid separator to cool the cab; the first end and the second end of the sixth three-way valve are connected, and the coolant flows through the first water pump, the cooler and the battery liquid cooling plate.

[0071] like Figure 3 As shown, if the cab temperature is higher than the cab air conditioning setting temperature, the average battery pack temperature is higher than the optimal temperature upper limit and has not reached the warning temperature, the air conditioning system refrigeration mode and the battery low-temperature water tank refrigeration mode are combined, then the first end and the second end of the first three-way valve are connected, and the second expansion valve is opened; the refrigerant flows through the compressor, the outdoor heat exchanger, the second electronic expansion valve and the evaporator, and returns to the gas-liquid separator; one end and three ends of the third three-way valve are connected, the first end and the third end of the fourth three-way valve are connected, one end and two ends of the seventh three-way valve are connected, the second end and the third end of the sixth three-way valve are connected, and the first end and the third end of the fifth three-way valve are connected; the coolant flows through the water pump, the PTC heater (not turned on), the battery liquid cold plate, and the low-temperature water tank in sequence.

[0072] like Figure 4As shown, if the cab temperature is higher than the cab air conditioning setting temperature, the average battery pack temperature is greater than the battery pack optimal temperature upper limit and greater than the warning temperature, the air conditioning refrigeration mode, the battery air conditioning cycle refrigeration mode and the motor / electronically controlled low-temperature water tank refrigeration mode are adopted; then the first end and the second end of the first three-way valve are connected, and the second three-way valve and the second and third electronic expansion valves are opened; the refrigerant flows through the compressor, the outdoor heat exchanger, and at the second three-way valve, a part flows to the second electronic expansion valve and the evaporator, and the other part flows to the third electronic expansion valve and the cooler, and finally flows back to the gas-liquid separator; the first end and the second end of the third three-way valve are connected, the first end and the third end of the fourth three-way valve are connected, the second end and the third end of the seventh three-way valve are connected, and the first end and the third end of the fifth three-way valve are connected, the first water pump is running, and the coolant flows through the first water pump, the cooler and the battery liquid cooling plate to exchange heat with the refrigerant at the cooler; the second water pump is running, and the coolant flows through the second water pump, the battery / motor liquid cooling plate and the low-temperature water tank.

[0073] like Figure 5 As shown, if the cab temperature is lower than the air-conditioning temperature and higher than the heat pump start-up temperature, the average temperature of the battery pack is not lower than the optimal temperature lower limit, and the heat pump heating mode and the battery balancing mode are adopted; the first end of the first three-way valve is connected to the third end, and the first electronic expansion valve is opened; the refrigerant flows through the compressor, the outdoor heat exchanger, the second electronic expansion valve, the evaporator, and returns to the gas-liquid separator; the first end and the second end of the sixth three-way valve are connected, and the coolant flows through the first water pump, the cooler and the battery liquid cooling plate.

[0074] like Figure 6 As shown, if the cab temperature is lower than the air-conditioning temperature and higher than the heat pump start-up temperature, the motor / electronic control water outlet temperature is greater than the recovery temperature, and the average temperature of the battery pack is slightly lower than the optimal temperature lower limit, the heat pump heating mode, the battery waste heat recovery heating mode and the motor / electronic control waste heat recovery heating mode are adopted; then the first end of the first three-way valve is connected to the second end, and the second electronic expansion valve is opened; the refrigerant flows through the compressor, the outdoor heat exchanger, the second electronic expansion valve, the evaporator, and returns to the gas-liquid separator; the second water pump is running, the first end and the second end of the third three-way valve, the fourth three-way valve, the first end and the second end of the seventh three-way valve, the second end and the third end of the sixth three-way valve, and the second end and the third end of the fifth three-way valve are connected, and the coolant flows through the second water pump, the motor / electronic control liquid cooling plate, the heater water tank, and the battery liquid cooling plate in sequence.

[0075] like Figure 7As shown, if the cab temperature is lower than the air-conditioning temperature and lower than the heat pump start-up temperature, the average temperature of the battery pack is lower than the optimal temperature lower limit, or rapid heating is required, the PTC heating mode and the battery PTC heating mode are adopted; the second water pump is operated, the first end and the third end of the third three-way valve, the fourth three-way valve, the first end and the second end of the seventh three-way valve, the second end and the third end of the sixth three-way valve, and the second end and the third end of the fifth three-way valve are connected in sequence, and the coolant flows through the second water pump, the PTC heater, the warm air water tank, and the battery liquid cooling plate in sequence.

[0076] In addition, if Figure 8 As shown, the present application also discloses a pure electric vehicle integrated thermal management method based on a heat pump air conditioner, using any of the above integrated thermal management systems, when the system is started, it is initialized and the cab air conditioning temperature T is set. cs ;

[0077] According to the vehicle sensor, obtain the ambient temperature T e , Cabin temperature T c , average battery pack temperature T b , Electric / electronically controlled outlet coolant temperature T m , compressor speedω c 、Motor speedω m data;

[0078] According to the different temperature requirements of each subsystem, determine the thermal management mode of each subsystem, control the opening and closing of the valve, and control the heating and cooling equipment; switch the mode according to the average temperature change of the battery pack and the temperature change of the cab, among which,

[0079] The determination of the cab thermal management subsystem mode includes:

[0080] If the cab temperature is higher than the cab air conditioning setting temperature, the air conditioning cooling mode is used;

[0081] If the cab temperature is slightly lower than the cab air conditioning setting temperature, and the electric / electronically controlled outlet coolant temperature is greater than the waste heat recovery threshold temperature, the motor / electronically controlled waste heat recovery heating mode is used;

[0082] If the cab temperature is lower than the cab air conditioning setting temperature and the ambient temperature is higher than the heat pump start-up temperature, the heat pump heating mode is used;

[0083] If the cab temperature is lower than the cab air conditioning setting temperature, the ambient temperature is lower than the heat pump start-up temperature, or when rapid heating is required, the PTC heating mode is used.

[0084] The determination of the battery thermal management subsystem mode includes:

[0085] If the average temperature of the battery pack is greater than the upper limit of the optimal temperature of the battery pack and less than the warning temperature, the battery low-temperature water tank cooling mode is adopted;

[0086] If the average temperature of the battery pack is greater than the upper limit of the optimal temperature of the battery pack and greater than the warning temperature, the battery air conditioning cooling mode is adopted;

[0087] If the average temperature of the battery pack is lower than the lower limit of the optimal temperature of the battery pack and the coolant temperature at the electric / electronically controlled outlet is higher than the waste heat recovery threshold temperature, the battery waste heat recovery heating mode is adopted;

[0088] If the average temperature of the battery pack is lower than the lower limit of the optimal temperature of the battery pack and the ambient temperature is lower than the heat pump start-up temperature, the battery PTC heating mode is adopted.

[0089] After the subsystem modes are integrated, the priority of each subsystem is established, including: giving priority to the temperature of the cab subsystem. After the system adjusts the cab temperature to a temperature value acceptable to the human body, it adjusts the temperature with the battery subsystem temperature control as the core.

[0090] At the same time, in the process of problem adjustment, for the control of cooling capacity, a sliding mode variable structure control model can be constructed based on the heat load analysis of the cab and battery system, which can be expressed as:

[0091] ω c =(e1-e2)+asgns+ks

[0092] Wherein, e1 represents the deviation between the system set temperature and the actual temperature, e2 represents the rate of change of the deviation between the system set temperature and the actual temperature, sgns represents the sign function, and k is the system gain;

[0093] Construct constraints, and determine the optimal controller parameters of the sliding mode controller based on the optimization algorithm with the minimum constraint value as the optimization goal to obtain the sliding mode controller. The expression of the constraint condition is:

[0094]

[0095] Where J is the error value, t is the time, τ is the integral intermediate variable of time t, T b is the battery pack temperature, T bs is the preset battery pack temperature, q is a constant, and the compressor speed is controlled by the system temperature difference to control the system cooling capacity.

[0096] According to the compressor speed, battery water inlet temperature, cab temperature, and air-conditioning set temperature, the electronic expansion valve EXV opening and PTC gear position are controlled by PID, and then it is determined whether each subsystem needs to change mode, and this cycle is repeated.

[0097] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall be included in the scope of the technical solution of the present invention.

Claims

1. A pure electric vehicle integrated thermal management system based on heat pump air conditioning, characterized in that: It includes a compressor, an outdoor heat exchanger, an evaporator, an indoor heat exchanger, a battery liquid cooling plate, a cooler, a valve mechanism, a first water pump, a second water pump, a motor liquid cooling plate, an electronically controlled liquid cooling plate, a warm air water tank, a low temperature water tank, a PTC heater, a gas-liquid separator, a fan and a blower. The valve mechanism includes a first three-way valve, a second three-way valve, a third three-way valve, a fourth three-way valve, a fifth three-way valve, a sixth three-way valve, a seventh three-way valve, a first electronic expansion valve, a second electronic expansion valve, and a third electronic expansion valve, wherein: The outlet of the gas-liquid separator is connected to the air inlet of the compressor, the exhaust port of the compressor is connected to the first three-way valve, the outdoor heat exchanger, the second three-way valve, and the evaporator in sequence, the cooler and the third electronic expansion valve are connected in series and connected to the second three-way valve, the indoor heat exchanger and the first electronic expansion valve are connected in series and arranged between the first three-way valve and the second three-way valve to form a heat pump air conditioning circulation loop; The first water pump is connected in series with the cooler, the battery liquid cooling plate, and the sixth three-way valve in sequence, the water inlet of the second water pump is connected to the low-temperature water tank, the water outlet of the second water pump is connected in series with the first end and the second end of the third three-way valve, the motor liquid cooling plate, the electronic control liquid cooling plate, the first end and the second end of the fourth three-way valve, the warm air heat exchanger, the first end and the second end of the seventh three-way valve, the battery liquid cooling plate, the second end and the third end of the sixth three-way valve, and the second end and the third end of the fifth three-way valve in sequence, and the third end of the third three-way valve is connected in series with the PTC heater, the first end and the third end of the fourth three-way valve, the second end and the third end of the seventh three-way valve, the first end and the third end of the fifth three-way valve, and the low-temperature water tank in sequence to form a battery coolant circulation loop.

2. A pure electric vehicle integrated thermal management system based on heat pump air conditioning according to claim 1, characterized in that: The heat pump air conditioning circulation loop and the battery coolant circulation loop exchange heat through a cooler, and the cooler includes a fan and a blower, wherein the fan provides the required air flow for the heat exchange between the outdoor radiator refrigerant and the air, and the blower provides the required air flow for the heat exchange between the heater water tank coolant and the air.

3. The integrated thermal management system for a pure electric vehicle based on a heat pump air conditioner according to claim 1, characterized in that: The integrated thermal management system includes a cab thermal management subsystem, a battery thermal management subsystem, and a motor / electronic control thermal management subsystem.

4. The integrated thermal management system for a pure electric vehicle based on a heat pump air conditioner according to claim 3, characterized in that: The cab thermal management subsystem includes an air conditioning cooling mode, a heat pump heating mode, a PTC heating mode and a motor / electronic control waste heat recovery heating mode.

5. The integrated thermal management system for a pure electric vehicle based on a heat pump air conditioner according to claim 1, characterized in that: The battery thermal management subsystem includes a battery balancing mode, a battery waste heat recovery heating mode, a battery PTC heating mode, a battery low-temperature water tank cooling mode, and a battery air conditioning circulation cooling mode.

6. The integrated thermal management system for pure electric vehicles based on heat pump air conditioning according to claim 1, characterized in that: The motor / electric control thermal management subsystem includes a motor / electric control low-temperature water tank refrigeration mode.

7. A method for integrated thermal management of pure electric vehicles based on heat pump air conditioning, characterized in that: The integrated thermal management system according to any one of claims 1 to 6 is used, when the system is started, it is initialized and the cab air conditioning temperature T is set. cs ; According to the vehicle sensor, obtain the ambient temperature T e , Cabin temperature T c , average battery pack temperature T b , Electric / electronically controlled outlet coolant temperature T m , compressor speedω c 、Motor speedω m data; According to the different temperature requirements of each subsystem, determine the thermal management mode of each subsystem, control the opening and closing of valves, and control the heating and cooling equipment; The switching mode is changed according to the average temperature change of the battery pack and the cabin temperature. The determination of the cab thermal management system mode includes: If the cab temperature is higher than the cab air conditioning setting temperature, the air conditioning cooling mode is used; If the cab temperature is slightly lower than the cab air conditioning setting temperature, and the electric / electronically controlled outlet coolant temperature is greater than the waste heat recovery threshold temperature, the motor / electronically controlled waste heat recovery heating mode is used; If the cab temperature is lower than the cab air conditioning setting temperature and the ambient temperature is higher than the heat pump start-up temperature, the heat pump air conditioning heating mode is used; If the cab temperature is lower than the cab air conditioning setting temperature, the ambient temperature is lower than the heat pump start-up temperature, or when rapid heating is required, the PTC heating mode is used. The determination of the battery thermal management system mode includes: If the average temperature of the battery pack is greater than the upper limit of the optimal temperature of the battery pack and less than the warning temperature, the low-temperature water tank cooling mode is adopted; If the average temperature of the battery pack is greater than the upper limit of the optimal temperature of the battery pack and greater than the warning temperature, the air conditioning cooling mode is used; If the average temperature of the battery pack is lower than the lower limit of the optimal temperature of the battery pack and the coolant temperature at the electric / electronically controlled outlet is higher than the waste heat recovery threshold temperature, the battery waste heat recovery heating mode is adopted; If the average temperature of the battery pack is lower than the lower limit of the optimal temperature of the battery pack and the ambient temperature is lower than the start-up temperature of the heat pump, the PTC heating mode is used.

8. The method for integrated thermal management of pure electric vehicles based on heat pump air conditioning according to claim 7, characterized in that: After the subsystem modes are integrated, the priority of each subsystem is established, including: giving priority to the temperature of the cab subsystem. After the system adjusts the cab temperature to a temperature value acceptable to the human body, it adjusts the temperature with the battery subsystem temperature control as the core.

9. The integrated thermal management method for pure electric vehicles based on heat pump air conditioning according to claim 7, characterized in that: Based on the analysis of the heat load of the cab and battery system, a sliding mode variable structure control model is constructed, which is expressed as: ω c =(e1-e2)+asgns+ks Wherein, e1 represents the deviation between the system set temperature and the actual temperature, e2 represents the rate of change of the deviation between the system set temperature and the actual temperature, sgns represents the sign function, and k is the system gain; Construct constraints, and determine the optimal controller parameters of the sliding mode controller based on the optimization algorithm with the minimum constraint value as the optimization goal to obtain the sliding mode controller. The expression of the constraint condition is: Where J is the error value, t is the time, τ is the integral intermediate variable of time t, T b is the battery pack temperature, T bs is the preset battery pack temperature, q is a constant, and the compressor speed is controlled by the system temperature difference to control the system cooling capacity.

10. The integrated thermal management method for pure electric vehicles based on heat pump air conditioning according to claim 7, characterized in that: The electronic expansion valve EXV opening and PTC gear position are controlled by PID algorithm according to the compressor speed, battery water inlet temperature, cab temperature and air conditioning set temperature.

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