A high-power lithium-ion power battery pack spray cooling system and a cooling method thereof

Abstract

A kind of high-power lithium ion power battery pack spray cooling system, including spray system, condensing system and data acquisition system: spray system includes compressor, condenser, storage liquid tank with refrigerant, filter, throttle valve, for placing power battery spray cavity and gas-liquid separator connected in pipeline in turn, spray cavity is equipped with spray pipe;Condensing system includes constant-temperature tank connected with condenser in loop, water pump and flowmeter are arranged in loop;Data acquisition system includes temperature sensor arranged in refrigerant circulation channel and water circulation channel and pressure sensor arranged in refrigerant circulation channel and data acquisition instrument.The present application can utilize the phase change spray of refrigerant to cool power battery, the surface temperature of battery is reduced by the latent heat of phase change of refrigerant to absorb the heat of power battery surface, and the method has strong heat dissipation capacity, and can cope with the thermal management demand of high-power lithium ion power battery such as high temperature, fast charging.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion power battery cooling technology, specifically to a high-power lithium-ion power battery pack spray cooling system and its cooling method. Background Technology

[0002] Faced with the dual pressures of energy depletion and environmental pollution, electric vehicles, with their advantages of being clean, environmentally friendly, and having high energy efficiency, are gradually becoming the trend in automobile development. Lithium-ion power batteries, with their advantages of high specific energy, long cycle life, good safety performance, and low self-discharge, are widely used in electric vehicles.

[0003] As lithium-ion batteries for vehicles gradually move towards higher power, many pressing issues have arisen, particularly the significant safety hazards posed by overheating, such as thermal runaway, spontaneous combustion, and even explosions, which threaten the personal safety and property of users. Among all available thermal management methods, air cooling was the earliest developed, boasting a simple structure, low operating cost, compact design, and high reliability. However, the low heat transfer coefficient of air makes it inefficient in heat dissipation. Traditional phase change material (PCM) cooling can prevent a rapid rise in battery temperature, but the heat absorbed by the PCM cannot be effectively dissipated to the surrounding environment through natural convection, requiring forced convection to dissipate the accumulated heat. Heat pipe cooling is relatively ideal, but it remains largely in the theoretical research stage. Liquid cooling is currently widely used in thermal management systems; however, it suffers from complex structures, heavy weight, and coolant leakage, and is insufficient to limit the temperature rise during rapid charging and discharging, failing to achieve the desired heat dissipation effect for high-rate power batteries. Summary of the Invention

[0004] The purpose of this invention is to provide a high-power lithium-ion power battery pack spray cooling system and cooling method to solve the problem of poor heat dissipation effect of existing cooling systems for high-power power batteries.

[0005] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0006] A high-power lithium-ion battery pack spray cooling system includes a spray system, a condensation system, and a data acquisition system. The spray system includes a compressor, a condenser, a liquid storage tank containing refrigerant, a filter, a throttle valve, a spray chamber for placing the power battery, and a gas-liquid separator. The compressor, condenser, liquid storage tank, filter, throttle valve, spray chamber, and gas-liquid separator are connected in sequence by pipes to form a refrigerant circulation channel. The spray chamber is equipped with a nozzle for absorbing heat from the power battery by causing a phase change of the refrigerant under the action of the throttle valve.

[0007] The condensation system includes a thermostatic bath that is connected to the condenser in a loop to form a water circulation channel, and a water pump and a flow meter are installed in the loop;

[0008] The data acquisition system includes temperature sensors installed in the refrigerant circulation channel and water circulation channel, and pressure sensors installed in the refrigerant circulation channel. A data acquisition instrument for collecting temperature and pressure information is connected to the temperature sensors and pressure sensors.

[0009] Furthermore, the refrigerant is R134a.

[0010] Furthermore, the temperature sensor includes a first temperature sensor disposed within the spray chamber for detecting the refrigerant temperature, and the pressure sensor includes a first pressure sensor disposed within the spray chamber for collecting the refrigerant pressure within the spray chamber.

[0011] Furthermore, the temperature sensor also includes a second temperature sensor disposed within the spray chamber for collecting the temperature of the top and four side surfaces of the power battery.

[0012] Furthermore, the nozzle is provided with nozzle holes whose diameter gradually decreases from the inlet end.

[0013] A cooling method for a high-power lithium-ion battery pack spray cooling system includes the following steps:

[0014] S1. Obtain the surface temperature T of the power battery. w When the surface temperature T w The compressor starts when the operating temperature of the power battery is exceeded.

[0015] S2. The refrigerant is pressurized by the compressor and cooled by the condenser in sequence. Then it is throttled and depressurized by the expansion valve and sprayed into the spray chamber, where it is atomized and phase-change absorbed by the power battery to dissipate heat.

[0016] S3. Monitor the surface temperature of the power battery. When the surface temperature is within the required operating temperature range of the power battery, shut down the compressor.

[0017] Furthermore, in S2, the heat exchange Q of the cooling water in the condenser absorbing the refrigerant is obtained, and the opening of the throttle valve is adjusted according to the heat exchange Q.

[0018] Furthermore, the process of obtaining the heat exchange Q is as follows:

[0019] Obtain the condensate flow rate m and the condensate inlet water temperature T of the condenser. in and outlet water temperature T out And the power consumption Qs of the compressor, calculate the heat exchange Q:

[0020] ;

[0021] In the formula: c p This is the specific heat capacity of the condensate.

[0022] Furthermore, the throttle valve opening adjustment process is as follows:

[0023] Obtain the temperature T of the refrigerant spray in the spray chamber. g The heat exchange area A and surface temperature T of the power battery w The heat generated by the power battery, Q', is obtained. The opening of the throttle valve is adjusted so that the heat generated, Q', is equal to the heat exchanged, Q.

[0024] Furthermore, in S1, the surface temperature T of the power battery w This is the average of five temperature points at the top and four sides of the power battery.

[0025] The beneficial effects of this invention are:

[0026] 1. The high-power lithium-ion power battery pack spray cooling system of the present invention forms a refrigerant circulation loop for cooling the power battery by setting up a compressor, condenser, throttle valve and spray chamber. It uses the phase change spray of refrigerant to cool the power battery, and absorbs the surface heat of the power battery through the latent heat of phase change of refrigerant, thereby reducing the surface temperature of the battery. This method has strong heat dissipation capacity and can meet the thermal management requirements of high-power lithium-ion power batteries such as high temperature and fast charging. While ensuring that the power battery is in a safe working state, it also ensures that the power battery is in a healthy working state as much as possible.

[0027] 2. The refrigerant used in the high-power lithium-ion power battery pack spray cooling system of the present invention is R134a, which has high cooling efficiency, low viscosity, does not easily adhere to the wall surface, and has a large latent heat value. A small amount of refrigerant can achieve the same cooling effect, which can fully meet the challenging thermal management requirements of power batteries such as high temperature and fast charging.

[0028] 3. The high-power lithium-ion power battery pack spray cooling system of the present invention has good temperature uniformity. After the refrigerant is sprayed into the cavity, it is directly atomized and dispersed throughout the evaporation cavity. It can control the cooling rate and temperature uniformity of the power battery, ensuring that the power battery is in a safe working state while ensuring that the power battery is in a healthy working state as much as possible, thus extending the cycle life of the power battery.

[0029] 4. The high-power lithium-ion power battery pack spray cooling system of the present invention can calculate the heat exchange of the refrigerant and the heat exchange of the power battery, and provide refrigerant spray regulation for the instantaneous heat release of the high-power lithium-ion power battery pack, so as to better realize the thermal management of the instantaneous heat release of the high-power lithium-ion power battery pack. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a high-power lithium-ion battery pack spray cooling system provided in the embodiment;

[0031] Figure 2This is a schematic diagram of the spray chamber structure;

[0032] Figure 3 This is a schematic diagram of the nozzle structure;

[0033] Figure 4 This is a schematic diagram showing the distribution of temperature measurement points for the power battery.

[0034] The diagram shows the following components: 1. Spray chamber, 2. Power battery, 3. Nozzle, 4. First valve, 5. Second valve, 6. Gas-liquid separator, 7. Compressor, 8. Condenser, 9. Third valve, 10. Thermostatic bath, 11. Water pump, 12. Flow meter, 13. Fourth valve, 14. Liquid storage tank, 15. Fifth valve, 16. Filter, 17. Throttling valve, 18. DC power supply, 19. Data acquisition instrument, 20. Computer. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. In the description of the present invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] As mentioned earlier, the heat generation of power batteries is related to the charge and discharge characteristics at different rates. The higher the charge and discharge rate, the more heat is generated. For high-power lithium-ion power battery packs, the instantaneous charge and discharge rate during application has a greater impact on heat management. Traditional air cooling or liquid cooling methods cannot respond in time to the instantaneous increase in heat generation of high-power power batteries, making it impossible for existing air cooling and liquid cooling methods to achieve the expected heat dissipation effect.

[0037] This invention provides a specific embodiment of a spray cooling system for high-power lithium-ion battery packs:

[0038] refer to Figure 1 As shown, the high-power lithium-ion battery pack spray cooling system of this embodiment includes a spray system, a condensation system, and a data acquisition system.

[0039] The spray system includes a compressor 7, a condenser 8, a liquid storage tank 14 containing refrigerant, a filter 16, a throttle valve 17, a spray chamber 1 for housing the power battery 2, and a gas-liquid separator 6. The compressor 7, condenser 8, liquid storage tank 14, filter 16, throttle valve 17, spray chamber 1, and gas-liquid separator 6 are connected in sequence to form a refrigerant circulation channel. The spray chamber 1 is a box-type structure that can form a sealed space. It is equipped with a spray pipe 3, which is connected to the throttle valve 17. After the throttle valve 17 is activated, the refrigerant is sprayed out, so that the refrigerant is dispersed in the spray chamber 1. The refrigerant after phase change absorbs heat from the power battery 2 in the spray chamber 1 and carries away the heat dissipated by the power battery 2. The spray chamber 1, as the core component of the cooling system, plays a role similar to that of an evaporator in a traditional refrigeration system.

[0040] The condensation system includes a water pump 11, a constant temperature bath 10, and the aforementioned condenser 8. The water pump 11, the constant temperature bath 10, and the condenser 8 are connected in a loop through pipelines to form a water circulation channel. A flow meter 12 is installed in the loop. The condensation effect of the condenser 8 is maintained through water circulation. A miniature DC diaphragm water pump can be installed to provide circulation power for the water circulation pipeline loop. By adjusting the flow rate of cooling water, the condenser 8 can maintain a good condensation effect. Understandably, a third valve 9 can be installed in the return section of the pipeline loop, and the water pump 11 and the flow meter 12 are installed in the outgoing section. A fourth valve 13 is installed in the outgoing section.

[0041] The data acquisition system includes a temperature sensor and a pressure sensor, as well as a data acquisition unit 19 connected to the temperature sensor and the pressure sensor. Understandably, it is also equipped with a DC power supply 18 and a computer 20, which displays the temperature and pressure information acquired by the data acquisition unit 19 in real time.

[0042] Combination Figure 1 As shown, pressure sensors can be installed in the refrigerant circulation channel as needed, and temperature sensors can be installed in the water circulation channel as needed. Understandably, multiple pressure sensors can be installed as needed to collect the refrigerant pressure in different pipe sections, and multiple temperature sensors can also be installed as needed to collect the refrigerant temperature in different pipe sections and the water temperature in different water circulation sections. Different types of thermocouples can also be selected according to different temperature measurement requirements. For example, armored thermocouples can be used to measure the water temperature, and T-type thermocouples can be used to measure the refrigerant temperature.

[0043] Combination Figure 1As shown, the temperature sensor is specifically configured to include a first temperature sensor installed in the spray chamber 1 to collect the temperature of the refrigerant inside the spray chamber 1 and a first pressure sensor for collecting the pressure of the refrigerant inside the spray chamber 1, so as to obtain the real-time temperature and pressure of the refrigerant spray inside the spray chamber 1. A second temperature sensor is also provided in the spray chamber 1 to collect the surface temperature of the power battery 2, so as to obtain the real-time surface temperature of the power battery 2.

[0044] When acquiring the real-time surface temperature of the power battery 2, five surface temperature measurement points are selected at the top and four sides of the power battery 2. The center of each surface is preferably one of these measurement points. The temperature values ​​at the five measurement points are T0 and T1, respectively. w1 T w2 T w3 T w4 T w5 The surface temperature of the power battery 2 is the average of five temperature measurement points to further reduce the impact of surface temperature non-uniformity. In specific implementation, this non-uniformity is evaluated by the maximum temperature difference and Sm.

[0045] ;

[0046] .

[0047] Combination Figure 1 and Figure 2 As shown, the nozzle 3 can be installed at the top of the spray chamber 1. The nozzle has multiple spray holes facing the bottom of the spray chamber 1. The nozzle 3 has a diameter of 8mm, and the spray holes can have diameters of 0.6mm-1.0mm. Figure 3 As shown, when the nozzles are set, their diameter gradually decreases from one end of the refrigerant inlet towards the direction away from the refrigerant inlet. According to Bernoulli's equation, when the diameter of each nozzle is equal, the refrigerant flow rate of each nozzle is different. By adopting a design that gradually decreases in diameter, the sprayed refrigerant flow rate is made close to or consistent, and the refrigerant spray distribution is more uniform.

[0048] The power battery 2 is placed below the nozzle 3. The refrigerant sprayed from the nozzle fills the spray chamber 1. After heat exchange with the power battery 2, it condenses into a liquid. Understandably, a discharge port for discharging refrigerant is provided at the bottom of the spray chamber 1. This discharge port is connected to the gas-liquid separator 6 through a pipe. A first valve 4 and a second valve 5 are sequentially provided on the pipe.

[0049] Understandably, in order to facilitate the control of each pipeline section, a fifth valve 15 and a filter 16 can be sequentially installed between the liquid storage tank 14 and the throttle valve 17. The filter 16 effectively ensures the quality of the refrigerant injected into the spray chamber 1 in the circuit.

[0050] In this embodiment, R134a is used as the refrigerant. When selecting a refrigerant, factors such as environmental acceptability, thermodynamic properties, electrical performance, and physicochemical properties need to be considered.

[0051] Using R134a:

[0052] Environmental acceptability: R134a has an ODP of 0 and a GWP (CO2=1) of 420. Compared with other types of refrigerants, its ODP and GWP values ​​are extremely small, thus meeting the requirements.

[0053] Thermodynamic properties: R134a is a medium-temperature refrigerant with a standard evaporation temperature of -26.5℃ and a standard freezing point of -101℃. R134a has low critical pressure, low critical temperature and critical density, high standard boiling point, high specific heat capacity, high pressure ratio and low discharge temperature, which are more conducive to the operation of the compressor.

[0054] Electrical properties: R134a has insulation properties close to those of air, and its resistivity is 1 million times that of water, thus exhibiting excellent insulation performance.

[0055] Physical and chemical properties: R134a has a high latent heat of vaporization and a moderate boiling point. Furthermore, R134a has the molecular formula CH2FCF3 and is a chlorine-free Freon that is non-toxic, non-flammable, odorless, and does not pollute the environment. It is safe, environmentally friendly, and inexpensive.

[0056] Specifically, in this embodiment, after R134a refrigerant is injected, it is in a superheated state inside the spray chamber 1. The ambient pressure is less than the saturated vapor pressure, and the R134a refrigerant will undergo a violent flash evaporation. After the refrigerant liquid is sprayed out, the high-speed droplets collide with the heating surface of the power battery 2, which can form a liquid film on the heating surface, as well as splash and bounce. After the liquid film and the splashed droplets flash evaporate, the temperature inside the spray chamber 1 is further reduced. The formed liquid film will also exchange heat with the high-temperature heating surface, mainly through convection heat transfer. If the temperature of the heating surface is too high, the liquid film will boil, resulting in boiling heat transfer. That is, the spray cooling of R134a refrigerant can be mainly divided into the following three stages: the first stage is the flash evaporation heat transfer stage of the droplets after being sprayed from the nozzle 3; the second stage is the heat exchange stage generated when the droplets collide with the heating surface; and the third stage is the flash evaporation, convection heat transfer, and boiling bubble heat transfer stage of the liquid film on the heating surface.

[0057] After R134a refrigerant is sprayed into the spray chamber 1 through the nozzle, the temperature inside the chamber drops rapidly, and the pressure inside the chamber rises accordingly. As the surface temperature of the power battery tends to stabilize, the spray cooling is in a dynamic equilibrium state. Since the actual temperature inside the chamber is always higher than the refrigerant saturation temperature corresponding to the chamber pressure, the refrigerant is directly atomized and dispersed throughout the evaporation chamber after being sprayed into the chamber, making the temperature of the battery surface more uniform.

[0058] Based on the above-described high-power lithium-ion battery pack spray cooling system, the present invention also provides a specific embodiment of a cooling method for the high-power lithium-ion battery pack spray cooling system:

[0059] The cooling method includes the following steps:

[0060] S1. Obtain the surface temperature T of power battery 2. w As mentioned earlier, the surface temperature T of power battery 2 w The temperature values ​​T at five measuring points can be used to determine the temperature. w1 T w2 T w3 T w4 T w5 Calculations show that when the surface temperature T w Once the operating temperature requirement of the power battery 2 is exceeded, the compressor 7 is started. Under normal circumstances, the operating temperature requirement of the power battery is 15℃~40℃. The actual operating temperature requirement of the power battery during operation can be set according to this range. When the temperature requirement is exceeded, the compressor 7 can be started to cool the power battery 2.

[0061] S2. After the compressor 7 starts, the refrigerant is first pressurized by the compressor 7 and cooled by the condenser 8. Then, after being throttled and depressurized by the expansion valve 17, it is sprayed into the spray chamber 1 along the nozzle 3. Under the combined action of the compressor 7, the condenser 8 and the expansion valve 17, the refrigerant is atomized and phase-changes in the spray chamber 1 to absorb the heat dissipated by the power battery 2.

[0062] S3, when the surface temperature T of power battery 2 w Once the operating temperature of the power battery 2 is within the required range, the compressor 7 is turned off to stop the refrigerant circulation.

[0063] The opening degree of the throttle valve 17 directly affects the pressure difference before and after throttling. As the throttling pressure difference increases, the inlet pressure through the nozzle 3 increases. After the refrigerant liquid enters the low-pressure spray chamber, flash evaporation occurs, the atomization effect is enhanced, and the surface cooling rate of the battery increases. Therefore, when the instantaneous heat dissipation of a high-power lithium-ion power battery pack is high, it is necessary to be able to adjust the opening degree of the throttle valve 17 in a timely manner.

[0064] In this cooling method, the heat exchange Q of the refrigerant absorbed by the cooling water in the condenser 8 is obtained in step S2. The opening of the throttle valve 17 is adjusted according to the heat exchange Q. The process of obtaining the heat exchange Q is as follows:

[0065] Obtain the flow rate (m) of condensate from condenser 8 and the inlet water temperature (T) of condenser 9. in and outlet water temperature T out And the power consumption Qs of the compressor, calculate the heat exchange Q:

[0066] ;

[0067] In the formula: c p This is the specific heat capacity of the condensate.

[0068] After obtaining the heat exchange rate Q, the temperature T of the refrigerant spray in the spray chamber 1 is then obtained. g The heat exchange area A and surface temperature T of power battery 2 w The heat generated by the power battery per unit time, Q', is obtained. The opening of the throttle valve 17 is adjusted so that the heat generated Q' is equal to the heat exchanged Q. This allows the cooling system to provide timely feedback on the instantaneous heat release when the instantaneous heat dissipation of the high-power lithium-ion power battery pack is high, thus meeting the thermal management requirements.

[0069] As mentioned earlier, in S1, the surface temperature T of the power battery 2 is... w The average of five temperature points (top and four sides) of the power battery can be used to ensure that the instantaneous heat dissipation of the power battery is fed back, so as to achieve good cooling of the power battery and ensure the temperature uniformity of the power battery.

[0070] It should be noted that the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A high-power lithium-ion battery pack spray cooling system, characterized in that, Includes a spray system, a condensation system, and a data acquisition system: The spray system includes a compressor (7), a condenser (8), a liquid storage tank (14) containing refrigerant, a filter (16), a throttle valve (17), a spray chamber (1) for placing the power battery (2), and a gas-liquid separator (6). The compressor (7), condenser (8), liquid storage tank (14), filter (16), throttle valve (17), spray chamber (1), and gas-liquid separator (6) are connected in sequence to form a refrigerant circulation channel. The spray chamber (1) is provided with a nozzle (3) for the refrigerant to undergo a phase change under the action of the throttle valve (17) to absorb heat from the power battery (2). The nozzle (3) is provided with nozzles whose diameter gradually decreases from the inlet end. The spray cooling of refrigerant can be divided into the following three stages: the first stage is the flash heat exchange stage of the droplets after being sprayed from the nozzle (3); the second stage is the heat exchange stage generated when the droplets collide with the heating surface; the third stage is the flash heat exchange, convection heat exchange and boiling bubble heat exchange stage of the liquid film on the heating surface. After the refrigerant is sprayed into the spray chamber (1) through the nozzle (3), the temperature inside the chamber drops rapidly and the pressure inside the chamber rises accordingly. As the surface temperature of the power battery tends to stabilize, the spray cooling is in a dynamic equilibrium state. Since the actual temperature inside the chamber is always higher than the refrigerant saturation temperature corresponding to the chamber pressure, the refrigerant is directly atomized and dispersed in the entire evaporation chamber after being sprayed into the chamber, making the temperature of the battery surface more uniform. The condensation system includes a constant temperature bath (10) that is connected to the condenser (8) to form a water circulation channel, and a water pump (11) and a flow meter (12) are provided in the loop. The data acquisition system includes a temperature sensor installed in the refrigerant circulation channel and a pressure sensor installed in the refrigerant circulation channel, and a data acquisition instrument (19) connected to the temperature sensor and the pressure sensor for collecting temperature and pressure information.

2. The high-power lithium-ion battery pack spray cooling system as described in claim 1, characterized in that, The refrigerant is R134a.

3. The high-power lithium-ion battery pack spray cooling system as described in claim 1, characterized in that, The temperature sensor includes a first temperature sensor disposed in the spray chamber (1) for detecting the temperature of the refrigerant, and the pressure sensor includes a first pressure sensor disposed in the spray chamber (1) for collecting the pressure of the refrigerant in the spray chamber (1).

4. The high-power lithium-ion battery pack spray cooling system as described in claim 3, characterized in that, The temperature sensor also includes a second temperature sensor disposed inside the spray chamber (1) for collecting the temperature of the top and four side surfaces of the power battery (2).

5. The cooling method of the high-power lithium-ion power battery pack spray cooling system as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Obtain the surface temperature T of the power battery (2). w When the surface temperature T w After the operating temperature requirement of the power battery (2) is exceeded, the compressor (7) is started. S2. After the refrigerant is pressurized by the compressor (7) and cooled by the condenser (8), it is then throttled and depressurized by the throttling valve (17) and sprayed into the spray chamber (1) to atomize and absorb the heat dissipation of the power battery (2) through phase change. S3, when the surface temperature T of the power battery (2) w Once the operating temperature of the power battery (2) is within the required range, the compressor (7) is turned off.

6. The cooling method of a high-power lithium-ion battery pack spray cooling system as described in claim 5, characterized in that, In S2, the heat exchange Q of the cooling water in the condenser (8) absorbing the refrigerant is obtained, and the opening of the throttle valve (17) is adjusted according to the heat exchange Q.

7. The cooling method of a high-power lithium-ion power battery pack spray cooling system as described in claim 6, characterized in that, The process of obtaining heat exchange Q is as follows: Obtain the flow rate m of the condensate from the condenser (8) and the inlet water temperature T of the condenser (8). in and outlet water temperature T out And the power consumption Qs of the compressor, calculate the heat exchange Q: ； In the formula: c p This is the specific heat capacity of the condensate.

8. The cooling method of a high-power lithium-ion power battery pack spray cooling system as described in claim 7, characterized in that, The opening adjustment process of the throttle valve (17) is as follows: Obtain the temperature T of the refrigerant spray in the spray chamber (1). g The heat exchange area A and surface temperature T of the power battery (2) w The heat generated by the power battery Q' is obtained, and the opening of the throttle valve (17) is adjusted so that the heat generated Q' is equal to the heat exchanged Q.

9. The cooling method of a high-power lithium-ion battery pack spray cooling system as described in claim 5, characterized in that, In S1, the surface temperature T of the power battery (2) w The average of the five temperature points at the top and four sides of the power battery (2) is the average value.

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