Temperature control device and control method thereof, and electric vehicle

Abstract

The present application provides a temperature control device and a control method thereof, and an electric vehicle. The device includes a control unit, a passenger compartment heat load detection unit, a compressor, a condenser, a battery management system (BMS), a passenger compartment air conditioning system, and a power battery cooling system; the compressor, the condenser, and the passenger compartment air conditioning system form a first closed loop, the compressor, the condenser, and the power battery cooling system form a second closed loop, and the refrigerant circulates in the first closed loop and the second closed loop; a first electronic expansion valve is provided on the pipeline connecting the passenger compartment air conditioning system to the condenser, and a second electronic expansion valve is provided on the pipeline connecting the power battery cooling system to the condenser. The control unit of the present application receives and determines the speed of the compressor according to the passenger compartment heat load data of the passenger compartment heat load detection unit and the battery heat load data of the battery management system, and adjusts the opening of the first electronic expansion valve and the second electronic expansion valve to cool the battery and the passenger compartment.

Description

Technical Field

[0001] The present application relates to the technical field of power battery cooling, and in particular to a temperature control device and a control method thereof, and an electric vehicle. Background Art

[0002] Power batteries are the main energy source for electric vehicles. When the vehicle is running under different driving conditions such as high speed, low speed, acceleration, and deceleration, the power battery will discharge at different rates and generate a lot of heat at different heat generation rates. In addition, the accumulation of time and the influence of space will produce uneven heat accumulation, which will lead to complex and changeable operating environment temperature of the battery pack. If it is not cooled in time and effectively, it will affect the performance and life of the battery. The most suitable operating temperature for power batteries is generally 25 degrees Celsius to 30 degrees Celsius. At the same time, in order to make the output voltage, current, and power of the battery as consistent as possible and give full play to the efficiency of the battery module, the temperature difference of the battery module must be within 5 degrees Celsius, that is, it has good uniformity.

[0003] At present, there are mainly the following cooling methods for power batteries:

[0004] (1) Natural air cooling

[0005] Natural cooling does not require additional equipment for heat exchange, and uses the temperature difference between the battery and the outside world to achieve heat transfer.

[0006] (2) Forced air cooling

[0007] Air cooling system components: cooling duct, fan, resistance wire.

[0008] Cooling and heating are achieved by using fans to introduce cold or hot air, supplemented by the design of air ducts inside and outside the battery pack. The selection of fans and the design of air duct structures directly affect the cooling effect of the battery pack air cooling system. The air flow rate needs to be determined based on the heat generation rate of the battery; the temperature rise requirements of each module need to be met; and a fan that meets the requirements is selected based on the air flow rate required by the system and the pressure drop curve of the system.

[0009] (3) Liquid cooling

[0010] The coolant circulation system is used to bring the heat of the battery to the outside or heat the battery. The coolant circulates in the battery cooling circuit to take away the heat of the battery module. The battery cooling circuit exchanges heat with the air conditioning cooling circuit through the chiller (liquid-to-liquid exchanger), and finally dissipates the heat outside the vehicle through the condenser of the front cooling module. Liquid cooling has a good cooling effect and can make the temperature distribution of the battery pack uniform, but liquid cooling has high requirements for the sealing of the battery pack, which not only increases the complexity of the system but also reduces the cooling effect. The liquid cooling system is heavy, expensive and large in size.

[0011] (4) Direct cooling with refrigerant

[0012] Direct cooling uses refrigerant (R134a) as the heat exchange medium. The refrigerant can absorb a large amount of heat during the gas-liquid phase change process. Compared with the refrigerant, the cooling rate can be greatly improved, and the heat inside the battery system can be taken away more quickly.

[0013] In the process of implementing the present invention, the inventors found that the prior art has at least the following technical problems:

[0014] The first type of natural cooling is a cooling method where the cooling capacity depends entirely on the external environment and is suitable for vehicles with smaller battery modules and less heat generation.

[0015] The second type of forced air cooling has a very low convective heat transfer coefficient, so the cooling and heating speeds are very slow.

[0016] The third type of liquid cooling is most widely used in actual vehicles. Liquid cooling has a good cooling effect and can make the temperature distribution of the battery pack uniform. However, liquid cooling has high requirements for the sealing of the battery pack, which not only increases the complexity of the system but also reduces the cooling effect. The liquid cooling system has low reliability, slow cooling rate, too many moving parts in the system, high weight and cost, and large volume.

[0017] There are fewer cases of vehicle-mounted applications of the fourth type, which is technically difficult and difficult to control. The controllability and uniformity of phase change heat absorption are poor.

[0018] In summary, the cooling technology of vehicle power batteries in the prior art needs to be further improved. Summary of the invention

[0019] The purpose of the present application is to provide a temperature control device and a control method thereof, and an electric vehicle, so as to reduce the complexity of the cooling system of the electric vehicle power battery and improve the cooling effect.

[0020] In order to achieve the purpose of the present application, the first aspect of the present application provides a temperature control device, including a control unit, a passenger compartment heat load detection unit, a compressor, a condenser, a battery management system (BMS), a passenger compartment air conditioning system and a power battery cooling system;

[0021] The compressor, condenser, and passenger compartment air conditioning system form a first closed loop, and the compressor, condenser, and power battery cooling system form a second closed loop, and refrigerant flows in the first closed loop and the second closed loop;

[0022] A first electronic expansion valve is provided on a pipeline connecting the passenger compartment air conditioning system to the condenser, and a second electronic expansion valve is provided on a pipeline connecting the power battery cooling system to the condenser;

[0023] The control unit is used to receive and determine the rotation speed of the compressor according to the passenger compartment heat load data of the passenger compartment heat load detection unit and the battery heat load data of the battery management system, and adjust the opening of the first electronic expansion valve and the second electronic expansion valve.

[0024] As an improvement of the first aspect, a gas-liquid separator is provided on the pipeline between the passenger compartment air conditioning system and the compressor.

[0025] As an improvement of the first aspect, the passenger compartment air conditioning system includes an air conditioning evaporator and a blower, and the blower is used to blow evaporated gas from the air conditioning evaporator to the passenger compartment.

[0026] As an improvement of the first aspect, the power battery cooling system includes a battery evaporator and multiple thermoelectric modules; the first contact surface of each thermoelectric module contacts the contact surface of the battery evaporator, and the second contact surface of each thermoelectric module contacts the contact surface of the power battery module. The control unit is also used to control the power on or off of the multiple thermoelectric modules according to the battery thermal load data.

[0027] As an improvement of the first aspect, the multiple thermoelectric modules are evenly arranged in the space between the battery evaporator and the power battery module along the flow direction of the refrigerant in the battery evaporator.

[0028] As an improvement of the first aspect, the air-conditioning evaporator has a first refrigerant inlet and a first refrigerant outlet, the first refrigerant inlet is connected to a first electronic expansion valve through a pipeline, the first refrigerant outlet is connected to the compressor through a pipeline, and the pipeline at the first refrigerant outlet is provided with a first temperature-pressure integrated sensor, and the control unit is also used to receive and determine the superheat of the refrigerant in the air-conditioning evaporator based on the temperature and pressure data of the first temperature-pressure integrated sensor.

[0029] As an improvement of the first aspect, the battery evaporator has a second refrigerant inlet and a second refrigerant outlet, the second refrigerant inlet is connected to a second electronic expansion valve through a pipeline, the second refrigerant outlet is connected to the compressor through a pipeline, and the pipeline at the second refrigerant outlet is provided with a second temperature-pressure integrated sensor, and the control unit is also used to receive and determine the superheat of the refrigerant in the battery evaporator based on the temperature and pressure data of the second temperature-pressure integrated sensor.

[0030] As an improvement of the first aspect, a throttle valve is arranged on the pipeline between the second refrigerant outlet and the second temperature-pressure integrated sensor, and the control unit is also used to receive and adjust the opening of the throttle valve according to the pressure data of the second temperature-pressure integrated sensor.

[0031] As an improvement of the first aspect, a pressure sensor is provided in the pipeline at the outlet of the condenser, and the control unit is further used to receive and control the speed of the cooling fan of the condenser according to the pressure data of the pressure sensor.

[0032] In order to achieve the purpose of the present application, the second aspect of the present application provides a control method of the temperature control device as described in the first aspect of the present application, comprising the following steps:

[0033] The passenger compartment heat load detection unit detects passenger compartment heat load data in real time, and the battery management system detects battery heat load data in real time;

[0034] The control unit receives and determines a compressor speed Z1 required for cooling the passenger compartment and a compressor speed Z2 required for cooling the battery according to the passenger compartment heat load data and the battery heat load data;

[0035] The control unit determines the speed of the compressor according to the compressor speed Z1 required for cooling the passenger compartment and the compressor speed Z2 required for cooling the battery, and sends corresponding control signals to adjust the openings of the first electronic expansion valve and the second electronic expansion valve.

[0036] As an improvement of the second aspect, the control unit determines the speed of the compressor according to the compressor speed Z1 required for cooling the passenger compartment and the compressor speed Z2 required for cooling the battery, specifically including:

[0037] Acquire the current operating mode of the vehicle, and determine the maximum allowable speed Zmax of the compressor according to the current operating mode of the vehicle;

[0038] If the sum Z of the speed Z1 and the speed Z2 is less than or equal to the maximum allowable speed Zmax of the compressor, the control unit sends a corresponding control signal to control the compressor to operate at the sum Z of the speed Z1 and the speed Z2 as the speed;

[0039] If the sum Z of the rotational speed Z1 and the rotational speed Z2 is greater than the maximum allowable rotational speed Zmax of the compressor, the control unit sends a corresponding control signal to control the compressor to operate at the maximum allowable rotational speed Zmax of the compressor as the rotational speed.

[0040] As an improvement of the second aspect, the adjusting the opening of the first electronic expansion valve and the second electronic expansion valve includes: adjusting the opening ratio of the first electronic expansion valve and the second electronic expansion valve according to the compressor speed Z1 required for cooling the passenger compartment, the compressor speed Z2 required for cooling the battery, and the maximum allowable compressor speed Zmax;

[0041] If the sum Z of the rotation speed Z1 and the rotation speed Z2 is less than or equal to the maximum allowable rotation speed Zmax of the compressor, a corresponding control signal is sent to adjust the opening ratio of the first electronic expansion valve and the second electronic expansion valve to Z1 / Z2;

[0042] If the sum Z of the rotational speed Z1 and the rotational speed Z2 is greater than the maximum allowable rotational speed Zmax of the compressor, a corresponding control signal is sent to adjust the opening ratio of the first electronic expansion valve and the second electronic expansion valve to (Zmax-Z2) / Z2.

[0043] As an improvement of the second aspect, the power battery cooling system includes a battery evaporator and a plurality of thermoelectric modules; a first contact surface of each thermoelectric module contacts a contact surface of the battery evaporator, and a second contact surface of each thermoelectric module contacts a contact surface of the power battery module;

[0044] The method further comprises the steps of:

[0045] When the control unit receives the battery thermal load data from the battery management system and starts the compressor to cool the power battery module, it sends a corresponding control signal to control the power supply of the multiple thermoelectric modules.

[0046] As an improvement of the second aspect, the plurality of thermoelectric modules are evenly arranged in the space between the battery evaporator and the power battery module along the flow direction of the refrigerant in the battery evaporator;

[0047] The sending of corresponding control signals to control the power supply of the multiple thermoelectric modules specifically includes:

[0048] Along the refrigerant flow direction in the battery evaporator, the thermoelectric modules in the upstream area where the refrigerant flows are controlled to be energized with a first preset current, and the thermoelectric modules in the downstream area where the refrigerant flows are controlled to be energized with a second preset current, wherein the first preset current is smaller than the second preset current.

[0049] As an improvement of the second aspect, the plurality of thermoelectric modules are evenly arranged in the space between the battery evaporator and the power battery module along the flow direction of the refrigerant in the battery evaporator;

[0050] The controlling the plurality of thermoelectric modules to be powered on specifically comprises:

[0051] Along the flow direction of the refrigerant in the battery evaporator, the current flowing through the thermoelectric module becomes larger and larger.

[0052] As an improvement of the second aspect, the air conditioner evaporator has a first refrigerant inlet and a first refrigerant outlet, the first refrigerant inlet is connected to a first electronic expansion valve through a pipeline, the first refrigerant outlet is connected to the compressor through a pipeline, and the pipeline at the first refrigerant outlet is provided with a first temperature and pressure integrated sensor;

[0053] The method comprises the following steps:

[0054] The first integrated temperature and pressure sensor detects the temperature and pressure of the pipeline at the first refrigerant outlet in real time;

[0055] The control unit receives the temperature and pressure data of the first temperature-pressure integrated sensor, determines the corresponding first reference temperature value according to the pressure data of the first temperature-pressure integrated sensor, and determines the superheat of the refrigerant in the air-conditioning evaporator according to the comparison result between the first reference temperature value and the temperature data of the first temperature-pressure integrated sensor.

[0056] As an improvement of the second aspect, the battery evaporator has a second refrigerant inlet and a second refrigerant outlet, the second refrigerant inlet is connected to the second electronic expansion valve through a pipeline, the second refrigerant outlet is connected to the compressor through a pipeline, and the pipeline at the second refrigerant outlet is provided with a second temperature and pressure integrated sensor;

[0057] The method comprises the following steps:

[0058] The second integrated temperature and pressure sensor detects the temperature and pressure of the pipeline at the second refrigerant outlet in real time;

[0059] The control unit receives temperature and pressure data from the second temperature-pressure integrated sensor, determines a corresponding second reference temperature value according to the pressure data from the second temperature-pressure integrated sensor, and determines the superheat of the refrigerant in the battery evaporator according to a comparison result between the second reference temperature value and the temperature data from the second temperature-pressure integrated sensor.

[0060] As an improvement of the second aspect, a throttle valve is provided on the pipeline between the second refrigerant outlet and the second temperature and pressure integrated sensor;

[0061] The method comprises the following steps:

[0062] The control unit also adjusts the opening of the throttle valve according to the pressure data of the second temperature-pressure integrated sensor; when the pressure data of the second temperature-pressure integrated sensor is less than the first pressure reference value, the control unit sends a corresponding control signal to adjust the opening of the throttle valve to decrease; when the pressure data of the second temperature-pressure integrated sensor is greater than the second pressure reference value, the control unit sends a corresponding control signal to adjust the opening of the throttle valve to increase; wherein the second pressure reference value is greater than the first pressure reference value.

[0063] As an improvement of the second aspect, the pipeline at the outlet of the condenser is provided with a pressure sensor;

[0064] The method comprises the following steps:

[0065] The control unit receives and controls the speed of the cooling fan of the condenser according to the pressure data of the pressure sensor. When the pressure data of the pressure sensor is greater than a third pressure reference value, the control unit sends a corresponding control signal to increase the speed of the cooling fan of the condenser.

[0066] In order to achieve the purpose of this application, the third aspect of this application provides an electric vehicle, including the temperature control device described in the first aspect of this application.

[0067] The above technical solution has at least the following beneficial effects:

[0068] A temperature control device is provided, including a control unit, a passenger compartment heat load detection unit, a compressor, a condenser, a battery management system (BMS), a passenger compartment air conditioning system and a power battery cooling system; a first electronic expansion valve is provided on a pipeline connecting the passenger compartment air conditioning system to the condenser, and a second electronic expansion valve is provided on a pipeline connecting the power battery cooling system to the condenser. Among them, the flow rate of the refrigerant is determined by the rotation speed of the compressor. The higher the rotation speed of the compressor, the more refrigerant is generated. Therefore, the control unit receives the passenger compartment heat load data of the passenger compartment heat load detection unit and the battery heat load data of the battery management system, thereby determining the refrigerant flow rate and the corresponding compressor speed required for cooling the passenger compartment and the power battery pack, and further determines the refrigerant flow rate ratio flowing into the passenger compartment air-conditioning system and the power battery cooling system according to the refrigerant flow rate required for cooling the passenger compartment and the power battery pack, adjusts the opening of the first electronic expansion valve and the second electronic expansion valve, controls the flow rate of liquid refrigerant flowing into the passenger compartment air-conditioning system and the power battery cooling system, and when the cooling demand of the passenger compartment and the power battery pack exceeds the capacity load of the compressor, gives priority to cooling the power battery pack, thereby reducing the complexity of the electric vehicle power battery cooling system and improving the cooling effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0070] Figure 1 This is a schematic structural diagram of a temperature control device described in an embodiment of the present application.

[0071] Figure 2 This is a schematic diagram of the closed-loop structure of a temperature control device described in Example 1 of the present application.

[0072] Figure 3 This is a three-dimensional diagram of the structure of a power battery cooling system described in Example 1 of the present application.

[0073] Figure 4 This is a partial structural breakdown diagram of a temperature control device described in Example 1 of the present application.

[0074] Figure 5 This is a flow chart of a temperature control method described in Example 2 of the present application.

[0075] Reference numerals:

[0076] Control unit 1, passenger compartment heat load detection unit 2, compressor 3, condenser 4, battery management system 5, passenger compartment air conditioning system 6, first electronic expansion valve 61, air conditioning evaporator 62, blower 63, power battery cooling system 7, second electronic expansion valve 71, battery evaporator 72, multiple thermoelectric modules 73, gas-liquid separator 8, power battery module 9, first temperature and pressure integrated sensor 10, second temperature and pressure integrated sensor 11, throttle valve 12, pressure sensor 13, cooling fan 14. DETAILED DESCRIPTION

[0077] Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0078] In addition, in order to better illustrate the present application, numerous specific details are provided in the specific embodiments below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In some examples, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present application.

[0079] In order to achieve the purpose of this application, Figure 1 As shown, embodiment 1 of the present application provides a temperature control device, including a control unit 1, a passenger compartment heat load detection unit 2, a compressor 3, a condenser 4, a battery management system 5 (BMS), a passenger compartment air conditioning system 6 and a power battery cooling system 7.

[0080] Among them, BMS is commonly known as the battery nanny or battery butler. Its main function is to intelligently manage and maintain each battery unit, prevent the battery from overcharging and over-discharging, extend the battery life, and monitor the battery status (including the thermal load of the power battery).

[0081] Furthermore, if Figure 2As shown, in this embodiment, the compressor 3, condenser 4, and passenger compartment air conditioning system 6 form a first closed loop, and the compressor 3, condenser 4, and power battery cooling system 7 form a second closed loop, and the refrigerant circulates in the first closed loop and the second closed loop.

[0082] Among them, a first electronic expansion valve 61 is provided on the pipeline connecting the passenger compartment air conditioning system 6 to the condenser 4 , and a second electronic expansion valve 71 is provided on the pipeline connecting the power battery cooling system 7 to the condenser 4 .

[0083] Specifically, the phase change and flow process of the refrigerant in this embodiment are as follows:

[0084] The flow process of refrigerant is as follows: Figure 2 As shown by the middle arrow, when the compressor 3 is started to rotate, the compressor compresses the gaseous refrigerant into a high-temperature and high-pressure refrigerant gas and then discharges it from the compressor 3. The high-temperature and high-pressure refrigerant gas discharged from the compressor 3 flows into the condenser 4 through the pipeline, dissipates heat and cools down in the condenser 4, and condenses into a high-temperature and high-pressure liquid refrigerant and flows out. The high-temperature and high-pressure liquid refrigerant enters the liquid storage and drying tank (generally welded as a whole with the condenser 4) through the pipeline, and is divided after being dried and filtered in the liquid storage and drying tank, and flows into the first electronic expansion valve 61 and the second electronic expansion valve 71 respectively. The high-temperature and high-pressure liquid refrigerant is throttled by the first electronic expansion valve 61 and the second electronic expansion valve 71 respectively, and its state changes sharply, becoming a low-temperature and low-pressure liquid refrigerant, and the low-temperature and low-pressure liquid refrigerant then enters the passenger compartment air conditioning system 6 and the power battery cooling system 7. The low-temperature and low-pressure liquid refrigerant undergoes a phase change in the passenger compartment air-conditioning system 6 and the power battery cooling system 7 to absorb heat and produce a cooling effect, and evaporates into a low-temperature and low-pressure gaseous refrigerant that flows back to the compressor 3 through a pipeline, thereby realizing the circulation of the refrigerant. During the flow process, the refrigerant will have different pressure, temperature and other states.

[0085] Among them, the control unit 1 of this embodiment is used to receive and determine the rotation speed of the compressor 3 according to the passenger compartment heat load data of the passenger compartment heat load detection unit 2 and the battery heat load data of the battery management system 5, and adjust the opening of the first electronic expansion valve 61 and the second electronic expansion valve 71. Among them, the heat load data indicates that the corresponding passenger compartment or power battery module 9 has a need for cooling. It should be noted that the detection and determination of the heat load can be carried out in one of the ways well known to those skilled in the art, which is not the main purpose of this application, so the detection and determination of the heat load will not be repeated here.

[0086] Specifically, the flow rate of the refrigerant is determined by the rotation speed of the compressor 3. The higher the rotation speed of the compressor 3, the more liquid refrigerant is generated. Therefore, in this embodiment, the control unit 1 receives the passenger compartment heat load data of the passenger compartment heat load detection unit 2 and the battery heat load data of the battery management system 5, thereby determining the refrigerant flow rate required for cooling the passenger compartment and the power battery pack and the corresponding compressor 3 rotation speed, and further determines the refrigerant flow rate ratio flowing into the passenger compartment air-conditioning system 6 and the power battery cooling system 7 according to the refrigerant flow rate required for cooling the passenger compartment and the power battery pack, adjusts the opening of the first electronic expansion valve 61 and the second electronic expansion valve 71, and controls the flow rate of liquid refrigerant flowing into the passenger compartment air-conditioning system 6 and the power battery cooling system 7.

[0087] It should be noted that when the cooling demand of the passenger compartment and the power battery pack exceeds the capacity load of the compressor 3, the temperature control device of this embodiment gives priority to cooling the power battery pack. Compared with the natural cooling, forced air cooling and liquid cooling of the prior art, the cooling effect is greatly improved. Moreover, compared with the night cooling system of the prior art, the temperature control device of this embodiment has a fast system cooling rate, low cost, light weight, and greatly reduced complexity.

[0088] In some embodiments, a gas-liquid separator 8 is provided on the pipeline between the passenger compartment air conditioning system 6 and the compressor 3 .

[0089] Specifically, the low-temperature and low-pressure liquid refrigerant undergoes a phase change in the passenger compartment air-conditioning system 6 and the power battery cooling system 7 to absorb heat and produce a cooling effect, and evaporates into a low-temperature and low-pressure gaseous refrigerant that flows back to the compressor 3 through a pipeline. In order to prevent some liquid refrigerant from entering the compressor 3 without completely evaporating, a gas-liquid separator 8 is provided in this embodiment to separate gas and liquid, so that the liquid refrigerant that has not completely evaporated into gas is filtered, and only the low-temperature and low-pressure gaseous refrigerant is allowed to flow back to the compressor 3 through a pipeline to prevent liquid hammer on the compressor 3.

[0090] In some embodiments, the passenger compartment air conditioning system 6 includes an air conditioning evaporator 62 and a blower 63 , and the blower 63 is used to blow evaporated gas from the air conditioning evaporator 62 to the passenger compartment.

[0091] Specifically, the blower 63 in this embodiment is placed in front of the air conditioning evaporator 62, and can blow air into the air duct, which leads to the passenger compartment, so as to blow the cold air evaporated by the air conditioning evaporator 62 into the passenger compartment to cool the passenger compartment.

[0092] For the cooling of power batteries, liquid cooling technology is already very mature, and most domestic and foreign competitors also use or are about to use liquid cooling systems. Liquid cooling systems are heavy, costly, and large in size. In order to meet the higher requirements for battery pack energy density in the future, to improve the lightweight level of the entire vehicle, and to reduce the cost of the entire vehicle, it is necessary to develop a refrigerant direct cooling system that is lighter than the liquid cooling system. The technical difficulty of the refrigerant direct cooling system is that the uniform temperature design of the battery evaporator 72 is very difficult, and the uniform temperature requirements of the battery must be met. The general requirement is that the temperature difference between the cells in the battery system does not exceed 5 degrees Celsius (cooling conditions); the overall system requires the evaporator to be precisely controlled, and the difficulty of the system control strategy increases.

[0093] In some embodiments, Figure 3-4 As shown, the power battery of the vehicle generally exists in the form of a power battery module 9, and the power battery cooling system 7 includes a battery evaporator 72 and a plurality of thermoelectric modules 73; wherein each thermoelectric module 73 has two opposite contact surfaces, wherein the first contact surface contacts the contact surface of the battery evaporator 72, and the second contact surface contacts the contact surface of the power battery module 9; the control unit 1 is also used to control the power on or off of the plurality of thermoelectric modules 73 according to the battery thermal load data.

[0094] Furthermore, in order to improve the temperature equalization effect of the thermoelectric module 73, the thermoelectric module 73 is a plate-like structure, and the contact surfaces of the battery evaporator 72 and the power battery module 9 with the thermoelectric module 73 are flat surfaces, and the thermoelectric module 73 is in close contact with the battery evaporator 72 and the power battery module 9 respectively.

[0095] Specifically, the liquid refrigerant absorbs heat during phase change in the battery evaporator 72 to provide a stable cold end for the power battery module 9. After the thermoelectric module 73 is powered on, a stable temperature difference is formed between the upper and lower surfaces. The side with a higher temperature contacts the battery evaporator 72, and the side with a lower temperature contacts the contact surface of the power battery module 9. The Peltier effect of the thermoelectric module 73 is used to cool the power battery. Since the intensity of the phase change heat absorption of the liquid refrigerant is difficult to control, the thermoelectric module 73 can control the temperature difference by adjusting the current. Along the direction of the channel flow in the battery evaporator 72, the refrigerant in the upstream area is mainly liquid, with a violent phase change and more heat absorption. As the heat exchange proceeds, the refrigerant gradually evaporates, the amount of liquid refrigerant in the downstream area decreases, the phase change gradually weakens, and the amount of heat absorption decreases. After the thermoelectric module 73 is arranged, the thermoelectric module 73 assists the refrigerant in cooling the power battery. Along the flow direction of the refrigerant, a smaller current is connected to the thermoelectric module 73 in the upstream area, and the temperature difference formed at both ends of the thermoelectric module 73 is smaller. A larger current is connected to the downstream area, and the temperature difference formed at both ends of the thermoelectric module 73 is larger, compensating for the temperature difference caused by the phase change, so that the temperature distribution of the power battery contact surface is uniform.

[0096] On the other hand, when the power battery module 9 needs to be heated, the second electronic expansion valve 71 prevents the liquid refrigerant from entering the battery evaporator 72, and changes the direction of current flow in the thermoelectric module 73 by reversing the positive and negative poles of the thermoelectric module 73 power supply, so as to exchange the direction of the temperature difference of the thermoelectric module 73 to heat the power battery module 9.

[0097] In some embodiments, based on the changes in the liquid refrigerant in the battery evaporator 72, the multiple thermoelectric modules 73 in this embodiment are evenly arranged in the space between the battery evaporator 72 and the power battery module 9 along the flow direction of the refrigerant in the battery evaporator 72, so as to adjust the current flowing through each thermoelectric module 73, thereby controlling the temperature difference, so as to better meet the uniform temperature requirements of the power battery module 9.

[0098] In some embodiments, the air-conditioning evaporator 62 has a first refrigerant inlet and a first refrigerant outlet, the first refrigerant inlet is connected to the first electronic expansion valve 61 through a pipeline, the first refrigerant outlet is connected to the compressor 3 through a pipeline, and the pipeline at the first refrigerant outlet is provided with a first temperature and pressure integrated sensor 10, and the control unit 1 is also used to receive and determine the superheat of the refrigerant in the air-conditioning evaporator 62 according to the temperature and pressure data of the first temperature and pressure integrated sensor 10.

[0099] Specifically, in this embodiment, the liquid refrigerant enters the air-conditioning evaporator 62 from the first refrigerant inlet and flows out of the air-conditioning evaporator 62 through the first refrigerant outlet.

[0100] According to the pressure value detected by the first temperature-pressure integrated sensor 10, the corresponding temperature (first reference temperature value) when the liquid refrigerant is completely evaporated can be found by looking up the table. Each pressure value has a corresponding reference temperature value. By comparing the temperature value detected by the first temperature-pressure integrated sensor 10 with the first reference temperature value, the superheat of the refrigerant can be known. The superheat is the temperature difference between the temperature value detected by the first temperature-pressure integrated sensor 10 and the first reference temperature value. When the temperature value detected by the first temperature-pressure integrated sensor 10 is greater than the first reference temperature value, it has a certain degree of superheat. Leaving a certain degree of superheat can ensure that the refrigerant is completely evaporated, and prevent part of the liquid refrigerant that has not been completely evaporated from entering the compressor 3 to cause liquid hammer. Based on this, it can also be judged whether the liquid refrigerant is fully evaporated and absorbs heat in the air-conditioning evaporator 62 to ensure heat exchange efficiency.

[0101] In some embodiments, the battery evaporator 72 has a second refrigerant inlet and a second refrigerant outlet, the second refrigerant inlet is connected to the second electronic expansion valve 71 through a pipeline, the second refrigerant outlet is connected to the compressor 3 through a pipeline, and the pipeline at the second refrigerant outlet is provided with a second temperature and pressure integrated sensor 11, and the control unit 1 is also used to receive and determine the superheat of the refrigerant in the battery evaporator 72 according to the temperature and pressure data of the second temperature and pressure integrated sensor 11.

[0102] Specifically, in this embodiment, the liquid refrigerant enters the battery evaporator 72 from the second refrigerant inlet, and flows out of the battery evaporator 72 through the second refrigerant outlet.

[0103] According to the pressure value detected by the second temperature-pressure integrated sensor 11, the corresponding temperature (second reference temperature value) when the liquid refrigerant is completely evaporated can be found by looking up the table. Each pressure value has a corresponding reference temperature value. By comparing the temperature value detected by the second temperature-pressure integrated sensor 11 with the second reference temperature value, the superheat of the refrigerant can be known. The superheat is the temperature difference between the temperature value detected by the second temperature-pressure integrated sensor 11 and the second reference temperature value. When the temperature value detected by the second temperature-pressure integrated sensor 11 is greater than the second reference temperature value, it has a certain degree of superheat. Leaving a certain degree of superheat can ensure that the refrigerant is completely evaporated, and prevent part of the liquid refrigerant that has not been completely evaporated from entering the compressor 3 to cause liquid hammer. Based on this, it can also be judged whether the liquid refrigerant is fully evaporated and absorbs heat in the battery evaporator 72 to ensure heat exchange efficiency.

[0104] In some embodiments, a throttle valve 12 is provided on the pipeline between the second refrigerant outlet and the second integrated temperature and pressure sensor 11 , and the control unit 1 is further used to receive and adjust the opening of the throttle valve 12 according to the pressure data of the second integrated temperature and pressure sensor 11 .

[0105] Specifically, in this embodiment, along the flow direction of the liquid refrigerant, the refrigerant at the front end of the battery evaporator 72 is mainly in liquid state, the phase change is fast, and the heat absorption is large. At the rear end of the battery evaporator 72, the liquid refrigerant has evaporated fully, the liquid refrigerant is small, and the heat absorption is small. When the pressure value fed back by the second temperature-pressure integrated sensor 11 is small, the air conditioning controller sends a signal to adjust the opening of the throttle valve 12 to reduce the pressure, increase the pressure in the battery evaporator 72, and reduce the phase change rate of the refrigerant in the front end area of ​​the battery evaporator 72, so that more liquid refrigerant evaporates and absorbs heat in the middle and rear ends, thereby improving the temperature uniformity of the battery evaporator 72 and reducing the temperature difference between the battery cells in the battery system. When the pressure value fed back by the second temperature-pressure integrated sensor 11 is too high, the air conditioning controller sends a signal to adjust the opening of the throttle valve 12 to increase the pressure of the battery cooling circuit to ensure the reliable operation of the system.

[0106] In this embodiment, a throttle valve 12 is added after the battery evaporator 72. By adjusting the pressure in the battery evaporator 72, the phase change rate of the liquid refrigerant in the front end area of ​​the battery evaporator 72 is controlled, so that more liquid refrigerant evaporates and absorbs heat in the middle and rear ends, thereby improving the temperature uniformity of the battery evaporator 72.

[0107] Based on the arrangement of the thermoelectric module 73 and the throttle valve 12, this embodiment greatly improves the controllability and uniformity of phase change heat absorption compared to the existing refrigerant direct cooling solution technology.

[0108] In some embodiments, a pressure sensor 13 is provided in the pipeline at the outlet of the condenser 4 , and the control unit 1 is further used to receive and control the speed of the cooling fan of the condenser 4 according to the pressure data of the pressure sensor 13 .

[0109] Specifically, the pressure sensor 13 is used to detect the pressure of the liquid refrigerant coming out of the condenser 4 (located in the front-end cooling module behind the front bumper of the car), which can be read from the CAN signal. Excessive pressure will damage the air-conditioning system (pipe blockage, bursting). When the pressure reaches a certain threshold, it is necessary to increase the speed of the cooling fan of the condenser 4 to improve the condensation effect of the condenser 4 and reduce the pressure.

[0110] It should be noted that the control unit 1 in the above embodiment may include one or more controllers, each used to perform corresponding control operations. In one example, some control functions can also be implemented by the air conditioner controller, which is conducive to reducing costs and optimizing system control.

[0111] In order to achieve the purpose of this application, the second embodiment of this application provides a control method of the temperature control device as described in the first embodiment of this application, such as Figure 5 As shown, the following steps are included:

[0112] S1: the passenger compartment heat load detection unit 2 detects the passenger compartment heat load data in real time, and the battery management system 5 detects the battery heat load data in real time;

[0113] S2 control unit 1 receives and determines a compressor 3 speed Z1 required for cooling the passenger compartment and a compressor 3 speed Z2 required for cooling the battery according to the passenger compartment heat load data and the battery heat load data;

[0114] S3 control unit 1 determines the speed of compressor 3 according to the speed Z1 of compressor 3 required for cooling the passenger compartment and the speed Z2 of compressor 3 required for cooling the battery, and sends corresponding control signals to adjust the opening of the first electronic expansion valve 61 and the second electronic expansion valve 71.

[0115] In some embodiments, in step S2 of this embodiment, the control unit 1 determines the speed of the compressor 3 according to the speed Z1 of the compressor 3 required for cooling the passenger compartment and the speed Z2 of the compressor 3 required for cooling the battery, specifically including:

[0116] The current operating mode of the vehicle is obtained, and the maximum allowable speed Zmax of the compressor 3 is determined according to the current operating mode of the vehicle; wherein, when the vehicle is in idle mode, the maximum allowable speed of the compressor 3 is a relatively small speed, and when the vehicle is in other modes, the maximum allowable speed of the compressor 3 is a relatively large speed. Therefore, the maximum allowable speed Zmax of the compressor 3 needs to be determined according to the current operating mode of the vehicle.

[0117] If the sum Z of the speed Z1 and the speed Z2 is less than or equal to the maximum allowable speed Zmax of the compressor 3, it means that the compressor 3 can simultaneously meet the requirements of cooling the passenger compartment and cooling the battery. Then the control unit 1 sends a corresponding control signal to control the compressor 3 to operate at the sum Z of the speed Z1 and the speed Z2 as the speed.

[0118] If the sum Z of the speed Z1 and the speed Z2 is greater than the maximum allowable speed Zmax of the compressor 3, it means that the compressor 3 cannot meet the requirements of cooling the passenger compartment and cooling the battery at the same time. Then the control unit 1 sends a corresponding control signal to control the compressor 3 to operate at the maximum allowable speed Zmax of the compressor 3 as the speed.

[0119] It should be noted that at this time, when allocating the flow rate of the liquid refrigerant, the cooling requirements of the power battery module 9 should be given priority.

[0120] Further, in step S2 of this embodiment, adjusting the opening of the first electronic expansion valve 61 and the second electronic expansion valve 71 includes:

[0121] The opening ratio of the first electronic expansion valve 61 and the second electronic expansion valve 71 is adjusted according to the compressor 3 speed Z1 required for cooling the passenger compartment, the compressor 3 speed Z2 required for cooling the battery, and the maximum allowable speed Zmax of the compressor 3 .

[0122] Among them, if the sum Z of the speed Z1 and the speed Z2 is less than or equal to the maximum allowable speed Zmax of the compressor 3, it means that the compressor 3 can simultaneously meet the cooling requirements of the passenger compartment and the battery. Then, the control unit 1 sends a corresponding control signal to adjust the opening ratio of the first electronic expansion valve 61 and the second electronic expansion valve 71 to Z1 / Z2, and the liquid refrigerant flow rate can be allocated as needed.

[0123] Among them, if the sum Z of the speed Z1 and the speed Z2 is greater than the maximum allowable speed Zmax of the compressor 3, it means that the compressor 3 cannot simultaneously meet the cooling needs of the passenger compartment and the battery, and the cooling needs of the power battery module 9 are given priority. The control unit 1 sends a corresponding control signal to adjust the opening ratio of the first electronic expansion valve 61 and the second electronic expansion valve 71 to (Zmax-Z2) / Z2.

[0124] In some embodiments, the power battery cooling system 7 includes a battery evaporator 72 and multiple thermoelectric modules 73; the first contact surface of each thermoelectric module 73 contacts the contact surface of the battery evaporator 72, and the second contact surface of each thermoelectric module 73 contacts the contact surface of the power battery module 9.

[0125] The method described in this embodiment also includes the following steps:

[0126] When the control unit 1 receives the battery thermal load data from the battery management system 5 and starts the compressor 3 to cool the power battery module 9, it sends a corresponding control signal to control the multiple thermoelectric modules 73 to be powered on, and utilizes the Peltier effect of the thermoelectric modules 73 to evenly cool the power battery module 9, thereby improving the temperature uniformity of the battery evaporator 72.

[0127] In some embodiments, the plurality of thermoelectric modules 73 are evenly arranged in the space between the battery evaporator 72 and the power battery module 9 along the flow direction of the refrigerant in the battery evaporator 72 .

[0128] As an example of a control method of a thermoelectric module 73, the sending of a corresponding control signal to control the power supply of the multiple thermoelectric modules 73 specifically includes:

[0129] Along the refrigerant flow direction in the battery evaporator 72, the thermoelectric module 73 in the upstream area of ​​the refrigerant flow is controlled to be energized with a first preset current, and the thermoelectric module 73 in the downstream area of ​​the refrigerant flow is controlled to be energized with a second preset current, and the first preset current is smaller than the second preset current.

[0130] As another example of a control method for the thermoelectric module 73, along the flow direction of the liquid refrigerant, the refrigerant at the front end of the battery evaporator 72 is mainly in liquid state, the phase changes quickly, and absorbs more heat. At the rear end of the battery evaporator 72, the liquid refrigerant has evaporated fully, the liquid refrigerant is less, and the heat absorption is less. Therefore, in this example, the control of the power-on of the multiple thermoelectric modules 73 specifically includes:

[0131] Along the flow direction of the refrigerant in the battery evaporator 72 , the current flowing through the thermoelectric module 73 becomes larger and larger.

[0132] The method of this embodiment combines phase change heat absorption and semiconductor refrigeration to provide cooling for the power battery, so the current of the thermoelectric module 73 is regulated to accurately maintain the uniformity of the temperature distribution of the contact wall of the power battery module 9. The thermoelectric module 73 is small in size, light in weight, and thin in thickness, so it is flexible in layout. It can be arranged in a part of the space between the cooling plate and the battery module or as full as possible. It only needs to control the current in the thermoelectric module 73, avoiding the problem of high difficulty and long cycle in the development of the electronic expansion valve control strategy.

[0133] In some embodiments, the air conditioning evaporator 62 has a first refrigerant inlet and a first refrigerant outlet, the first refrigerant inlet is connected to the first electronic expansion valve 61 through a pipeline, the first refrigerant outlet is connected to the compressor 3 through a pipeline, and the pipeline at the first refrigerant outlet is provided with a first temperature and pressure integrated sensor 10.

[0134] The method described in this embodiment includes the following steps:

[0135] The first integrated temperature and pressure sensor 10 detects the temperature and pressure of the pipeline at the first refrigerant outlet in real time;

[0136] The control unit 1 receives the temperature and pressure data of the first temperature-pressure integrated sensor 10, determines the corresponding first reference temperature value according to the pressure data of the first temperature-pressure integrated sensor 10, and determines the superheat of the refrigerant in the air-conditioning evaporator 62 according to the comparison result between the first reference temperature value and the temperature data of the first temperature-pressure integrated sensor 10.

[0137] In some embodiments, the battery evaporator 72 has a second refrigerant inlet and a second refrigerant outlet, the second refrigerant inlet is connected to the second electronic expansion valve 71 through a pipeline, the second refrigerant outlet is connected to the compressor 3 through a pipeline, and the pipeline at the second refrigerant outlet is provided with a second temperature and pressure integrated sensor 11.

[0138] The method described in this embodiment includes the following steps:

[0139] The second integrated temperature and pressure sensor 11 detects the temperature and pressure of the pipeline at the second refrigerant outlet in real time;

[0140] The control unit 1 receives the temperature and pressure data of the second temperature-pressure integrated sensor 11, determines the corresponding second reference temperature value according to the pressure data of the second temperature-pressure integrated sensor 11, and determines the superheat of the refrigerant in the battery evaporator 72 according to the comparison result between the second reference temperature value and the temperature data of the second temperature-pressure integrated sensor 11.

[0141] In some embodiments, a throttle valve 12 is provided on the pipeline between the second refrigerant outlet and the second integrated temperature and pressure sensor 11 .

[0142] The method described in this embodiment includes the following steps:

[0143] The control unit 1 also adjusts the opening of the throttle valve 12 according to the pressure data of the second temperature-pressure integrated sensor 11; when the pressure data of the second temperature-pressure integrated sensor 11 is less than the first pressure reference value, the control unit 1 sends a corresponding control signal to reduce the opening of the throttle valve 12; when the pressure data of the second temperature-pressure integrated sensor 11 is greater than the second pressure reference value, the control unit 1 sends a corresponding control signal to increase the opening of the throttle valve 12; wherein the second pressure reference value is greater than the first pressure reference value.

[0144] In some embodiments, a pressure sensor 13 is provided in the pipeline at the outlet of the condenser 4 .

[0145] The method described in this embodiment includes the following steps:

[0146] The control unit 1 receives and controls the speed of the cooling fan of the condenser 4 according to the pressure data of the pressure sensor 13. When the pressure data of the pressure sensor 13 is greater than the third pressure reference value, the control unit 1 sends a corresponding control signal to increase the speed of the cooling fan of the condenser 4, thereby improving the condensation effect of the condenser 4 and reducing the pressure.

[0147] It should be noted that the method described in Example 2 corresponds to the device described in Example 1. Therefore, other related parts not described in detail in Example 2 can be obtained by referring to the device described in Example 1, and the parts in Example 2 will not be repeated here.

[0148] In order to achieve the purpose of the present application, embodiment 3 of the present application provides an electric vehicle, including the temperature control device described in embodiment 1 of the present application.

[0149] From the description of the above embodiments, it can be seen that the control unit of the embodiment of the present application receives the passenger compartment heat load data of the passenger compartment heat load detection unit and the battery heat load data of the battery management system, and determines the refrigerant flow rate and the corresponding compressor speed required for cooling the passenger compartment and the power battery pack through these load data, and further adjusts the opening of the first electronic expansion valve and the second electronic expansion valve according to the refrigerant flow rate required for cooling the passenger compartment and the power battery pack, controls the flow rate of liquid refrigerant flowing into the passenger compartment air-conditioning system and the power battery cooling system, and when the cooling demand of the passenger compartment and the power battery pack exceeds the capacity load of the compressor, gives priority to cooling the power battery pack, thereby reducing the complexity of the electric vehicle power battery cooling system and improving the cooling effect.

[0150] In addition, the embodiment of the present application also utilizes the characteristic of temperature difference generated when the thermoelectric module is powered on (Peltier effect) to regulate the temperature difference between the battery evaporator and the power battery, and improve the uniformity of the surface temperature distribution of the power battery when the refrigerant of the electric vehicle power battery is directly cooled. When the car is driving or charging, the refrigerant in the battery evaporator absorbs heat during phase change to provide a stable cold end for the power battery. After the thermoelectric module is powered on, a stable temperature difference is formed between the upper and lower surfaces. The side with a high temperature contacts the battery evaporator, and the side with a low temperature contacts the contact wall of the power battery module, and the Peltier effect is used to cool the power battery. Since the intensity of the phase change heat absorption of the refrigerant is difficult to control, the controller controls the temperature difference by adjusting the current of the thermoelectric module, and accordingly regulates the current of the thermoelectric modules in different regions to accurately maintain the uniformity of the temperature distribution of the contact wall of the power battery module.

[0151] In the description of this specification, the description of reference terms such as "some embodiments" means that the specific features described in conjunction with the embodiments or examples are included in at least one embodiment of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment. Moreover, the specific features described can be combined in any one or more embodiments in a suitable manner.

[0152] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A control method for a temperature control device, characterized in that: The temperature control device includes a control unit, a passenger compartment heat load detection unit, a compressor, a condenser, a battery management system, a passenger compartment air conditioning system and a power battery cooling system; the compressor, the condenser and the passenger compartment air conditioning system form a first closed loop, the compressor, the condenser and the power battery cooling system form a second closed loop, and the refrigerant flows in the first closed loop and the second closed loop; a first electronic expansion valve is provided on a pipeline connecting the passenger compartment air conditioning system to the condenser, and a second electronic expansion valve is provided on a pipeline connecting the power battery cooling system to the condenser; The method comprises the following steps: The passenger compartment heat load detection unit detects passenger compartment heat load data in real time, and the battery management system detects battery heat load data in real time; The control unit receives and determines a compressor speed Z1 required for cooling the passenger compartment and a compressor speed Z2 required for cooling the battery according to the passenger compartment heat load data and the battery heat load data; The control unit determines the speed of the compressor according to the compressor speed Z1 required for cooling the passenger compartment and the compressor speed Z2 required for cooling the battery, and sends a corresponding control signal to adjust the opening of the first electronic expansion valve and the second electronic expansion valve; The control unit determines the speed of the compressor according to the compressor speed Z1 required for cooling the passenger compartment and the compressor speed Z2 required for cooling the battery, specifically including: Acquire the current operation mode of the vehicle, and determine the maximum allowable speed Zmax of the compressor according to the current operation mode of the vehicle; if the sum Z of the speed Z1 and the speed Z2 is less than or equal to the maximum allowable speed Zmax of the compressor, the control unit sends a corresponding control signal to control the compressor to operate at the sum Z of the speed Z1 and the speed Z2 as the speed; if the sum Z of the speed Z1 and the speed Z2 is greater than the maximum allowable speed Zmax of the compressor, the control unit sends a corresponding control signal to control the compressor to operate at the maximum allowable speed Zmax of the compressor as the speed; The adjusting the opening of the first electronic expansion valve and the second electronic expansion valve includes: adjusting the opening ratio of the first electronic expansion valve and the second electronic expansion valve according to the compressor speed Z1 required for cooling the passenger compartment, the compressor speed Z2 required for cooling the battery, and the maximum allowable speed Zmax of the compressor; wherein, if the sum Z of the speed Z1 and the speed Z2 is less than or equal to the maximum allowable speed Zmax of the compressor, a corresponding control signal is issued to adjust the opening ratio of the first electronic expansion valve and the second electronic expansion valve to Z1 / Z2; if the sum Z of the speed Z1 and the speed Z2 is greater than the maximum allowable speed Zmax of the compressor, a corresponding control signal is issued to adjust the opening ratio of the first electronic expansion valve and the second electronic expansion valve to (Zmax-Z2) / Z2.

2. The control method according to claim 1, characterized in that: The power battery cooling system includes a battery evaporator and a plurality of thermoelectric modules; a first contact surface of each thermoelectric module contacts a contact surface of the battery evaporator, and a second contact surface of each thermoelectric module contacts a contact surface of the power battery module; The method further comprises the steps of: When the control unit receives the battery thermal load data from the battery management system and starts the compressor to cool the power battery module, it sends a corresponding control signal to control the power supply of the multiple thermoelectric modules.

3. The control method according to claim 2, characterized in that: The multiple thermoelectric modules are evenly arranged in the space between the battery evaporator and the power battery module along the flow direction of the refrigerant in the battery evaporator; The sending of corresponding control signals to control the power supply of the multiple thermoelectric modules specifically includes: Along the refrigerant flow direction in the battery evaporator, the thermoelectric modules in the upstream area where the refrigerant flows are controlled to be energized with a first preset current, and the thermoelectric modules in the downstream area where the refrigerant flows are controlled to be energized with a second preset current, wherein the first preset current is smaller than the second preset current.

4. The control method according to claim 2, characterized in that: The multiple thermoelectric modules are evenly arranged in the space between the battery evaporator and the power battery module along the flow direction of the refrigerant in the battery evaporator; The controlling the plurality of thermoelectric modules to be powered on specifically comprises: Along the flow direction of the refrigerant in the battery evaporator, the current flowing through the thermoelectric module becomes larger and larger.

5. The control method according to claim 1, characterized in that: The passenger compartment air conditioning system includes an air conditioning evaporator and a blower, wherein the blower is used to blow evaporated gas from the air conditioning evaporator to the passenger compartment, the air conditioning evaporator has a first refrigerant inlet and a first refrigerant outlet, the first refrigerant inlet is connected to a first electronic expansion valve through a pipeline, the first refrigerant outlet is connected to the compressor through a pipeline, and the pipeline at the first refrigerant outlet is provided with a first temperature and pressure integrated sensor; The method comprises the following steps: The first integrated temperature and pressure sensor detects the temperature and pressure of the pipeline at the first refrigerant outlet in real time; The control unit receives the temperature and pressure data of the first temperature-pressure integrated sensor, determines the corresponding first reference temperature value according to the pressure data of the first temperature-pressure integrated sensor, and determines the superheat of the refrigerant in the air-conditioning evaporator according to the comparison result between the first reference temperature value and the temperature data of the first temperature-pressure integrated sensor.

6. The control method according to claim 5, characterized in that: The battery evaporator has a second refrigerant inlet and a second refrigerant outlet, the second refrigerant inlet is connected to the second electronic expansion valve through a pipeline, the second refrigerant outlet is connected to the compressor through a pipeline, and the pipeline at the second refrigerant outlet is provided with a second temperature and pressure integrated sensor; The method comprises the following steps: The second integrated temperature and pressure sensor detects the temperature and pressure of the pipeline at the second refrigerant outlet in real time; The control unit receives temperature and pressure data from the second temperature-pressure integrated sensor, determines a corresponding second reference temperature value according to the pressure data from the second temperature-pressure integrated sensor, and determines the superheat of the refrigerant in the battery evaporator according to a comparison result between the second reference temperature value and the temperature data from the second temperature-pressure integrated sensor.

7. The control method according to claim 6, characterized in that: A throttle valve is provided on the pipeline between the second refrigerant outlet and the second temperature and pressure integrated sensor; The method comprises the following steps: The control unit also adjusts the opening of the throttle valve according to the pressure data of the second temperature-pressure integrated sensor; when the pressure data of the second temperature-pressure integrated sensor is less than the first pressure reference value, the control unit sends a corresponding control signal to adjust the opening of the throttle valve to decrease; when the pressure data of the second temperature-pressure integrated sensor is greater than the second pressure reference value, the control unit sends a corresponding control signal to adjust the opening of the throttle valve to increase; wherein the second pressure reference value is greater than the first pressure reference value.

8. The control method according to claim 1, characterized in that: The pipeline at the outlet of the condenser is provided with a pressure sensor; The method comprises the following steps: The control unit receives and controls the speed of the cooling fan of the condenser according to the pressure data of the pressure sensor. When the pressure data of the pressure sensor is greater than a third pressure reference value, the control unit sends a corresponding control signal to increase the speed of the cooling fan of the condenser.

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