A direct cooling battery thermal management method and management system thereof

Abstract

The present invention discloses a direct cooling battery thermal management method and its management system, which belongs to the field of battery thermal management, including a compressor, a condenser, and a first temperature sensor. One end of the first temperature sensor is connected in series with a drying filter, one end of the drying filter is connected in parallel with a total control flow path, and a battery refrigeration component is commonly provided between the first direct cooling plate and the second direct cooling plate. When the present application is in use, the precise control of the first solenoid valve and the first electronic expansion valve can realize the precise regulation of the refrigerant flow entering the first control branch, and the sixth temperature sensor is used to monitor the maximum temperature of the battery pack in real time. When the temperature exceeds the preset standard, the battery pack is cooled by the first direct cooling plate to ensure that it remains within the preset standard temperature, so that the problem of uneven heat distribution inside the battery pack can be more effectively dealt with, and the temperature difference between the parts can be reduced, thereby improving the reliability of the entire system and the long-term durability of the battery.

Description

Technical Field

[0001] The present invention relates to the technical field of battery thermal management, and more specifically to a direct-cooling battery thermal management method and a management system thereof. Background Art

[0002] With the rapid rise of the electric vehicle industry in recent years, battery thermal management technology has also made significant progress. The cooling mode of the direct-cooled battery thermal management system provides the ultimate operating temperature range for the electric vehicle battery pack, thereby optimizing the battery's performance during charging and discharging and extending its service life, so that pure electric vehicles will continue to use electrical energy while running, which means that compared with hybrid vehicles, they have higher requirements for energy efficiency and system reliability.

[0003] Existing electric vehicles that use direct cooling systems have some defects in battery thermal management, especially in maintaining the temperature uniformity of the battery pack. This problem usually stems from uneven heat generation within the battery pack, especially in the area near the lugs. In addition, since the refrigerant direct cooling plate is mostly arranged on one side of the bottom of the battery, this design is difficult to effectively deal with the uneven distribution of heat generated inside the battery pack, resulting in some areas with significantly higher temperatures than other areas, resulting in a large temperature difference between the various parts of the battery, affecting the reliability of the entire system and the long-term durability of the battery. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a direct-cooling battery thermal management method and a management system thereof, aiming to solve the above-mentioned technical problems.

[0005] To solve the above problems, the present invention adopts the following technical solutions.

[0006] A direct cooling battery thermal management method comprises the following steps:

[0007] Step 1: When the electric vehicle is started, the temperature difference between the cabin ambient temperature and the preset standard of 24°C, and the temperature difference between the battery pack maximum temperature and the preset standard of 40°C are calculated; if the cabin ambient temperature exceeds 24°C, the first solenoid valve is opened, the first electronic expansion valve is opened, and the evaporator is used to absorb the heat in the cabin so that the cabin temperature reaches the preset standard; if the temperature of the battery pack exceeds 40°C, the second solenoid valve and the second electronic expansion valve are opened, and the first direct cooling plate is used to cool the refrigerant flow so that the battery pack reaches the preset standard;

[0008] Step 2, set the number of particles, each particle represents a set of control parameters, including the opening of the first electronic expansion valve and the speed of the compressor; initialize the position and speed for each particle, where the position represents the initial value of the control parameter, and the speed represents the direction and rate of change of the control parameter; define a fitness function for evaluating the stability of the cabin temperature and energy consumption under each set of control parameters; use a temperature sensor to monitor the cabin temperature in real time and compare it with the preset comfort range of 24℃±0.5℃; when the cabin temperature exceeds the comfort range, start the particle swarm optimization algorithm; for each particle, simulate the operation according to its current control parameter value, and calculate the fitness value through the fitness function; update The individual final solution and the global final solution of each particle are obtained; the speed and position of each particle are updated according to the individual final solution and the global final solution, that is, the value of the control parameter is adjusted, and the iteration is repeated until the preset number of iterations is reached to obtain the global final solution; according to the global final solution, the final opening value of the first electronic expansion valve is obtained; if the current opening of the first electronic expansion valve has not reached the final value, its opening is gradually increased until it reaches the final value; if the first electronic expansion valve is fully opened, but the temperature in the cabin still needs to be further regulated, the final speed value of the compressor is obtained according to the global final solution output by the particle swarm optimization algorithm; the speed of the compressor is adjusted to the final value to further reduce and stabilize the temperature in the cabin;

[0009] Step 3, continue to monitor the temperature difference inside the battery pack. If the temperature difference continues to be higher than 5°C, check the state of the third electronic expansion valve; if the third electronic expansion valve is not fully open, gradually increase its opening to reduce the temperature difference.

[0010] As a further solution of the present invention: the calculation formula of the fitness function is:

[0011] ;

[0012] in, represents the value of the fitness function, which is used to evaluate the stability of the cabin temperature and the energy consumption under the control parameters; Indicates the current cabin temperature; Indicates the current maximum temperature of the battery pack; Indicates the temperature difference inside the battery pack, that is, the difference between the highest temperature and the lowest temperature in the battery pack; and The indices representing the cabin temperature, the maximum temperature of the battery pack, and the temperature difference within the battery pack are used to adjust the sensitivity of these temperature deviations in the fitness function; The penalty coefficient for cabin temperature change is used to penalize the cabin temperature when it deviates from the preset target value. It represents the penalty coefficient of ambient temperature on energy efficiency, which is used to consider the impact of external ambient temperature on system energy efficiency; Indicates the penalty coefficient of the temperature difference inside the battery pack, which is used to penalize the situation where the temperature difference inside the battery pack deviates from the target value; Indicates the speed of the compressor in the refrigeration system; represents the opening of the electronic expansion valve; γ and δ represent nonlinear control parameters, which are used to adjust the influence of the compressor speed and the opening of the electronic expansion valve in the fitness function; represents the ambient temperature outside the vehicle; t represents time, which is used to consider the impact of system operation time on fitness; , Respectively represent the weight coefficients of compressor speed, electronic expansion valve opening and time, which are used to balance the importance of these factors in the fitness function;

[0013] in, Indicates the current cabin temperature The exponential form of the deviation from the preset target temperature of 24°C; Indicates the current maximum temperature of the battery pack The exponential form of the deviation from the preset standard temperature of 40°C; Indicates battery temperature difference The exponential form of the difference from the daily standard value of 5°C; represents the attenuation term with the square of cabin temperature deviation as the exponential, The penalty coefficient representing the temperature change rate is used to penalize the case where the cabin temperature deviates from the target temperature; , They represent the nonlinear control parameters of the compressor speed and the electronic expansion valve opening, respectively, where γ and δ are the corresponding exponents; Indicates the temperature outside the vehicle Impact on system energy efficiency, Represents the penalty coefficient of ambient temperature on energy efficiency; Indicates the external ambient temperature The difference from the target value of 25°C.

[0014] As a further solution of the present invention: the speed and position of each particle are updated, and the speed update formula is:

[0015] ;

[0016] in, represents particle i at time speed; represents the velocity of particle i at time t; represents the position of particle i at time t; represents the individual final position of particle i; Indicates the final global position; , represents the acceleration constant; , represents a random number in the range [0, 1]; w represents the weight;

[0017] The update formula of position is:

[0018] ;

[0019] in, represents particle i at time location.

[0020] As a further solution of the present invention: the specific operation process of step 3 is as follows: if it is detected that the temperature difference inside the battery pack (23) exceeds 5°C, the third solenoid valve and the third electronic expansion valve will be opened to optimize the temperature distribution; the temperature difference change will continue to be monitored, and if the temperature difference continues to be higher than 5°C, the state of the third electronic expansion valve will be checked. If the third electronic expansion valve is not fully open, the opening of the third electronic expansion valve will be increased, and the temperature difference will be reduced by increasing the speed of the compressor; finally, when the temperature difference of the battery pack returns to within 5°C, the existing settings will be maintained to ensure safe operation of the battery pack.

[0021] As a further solution of the present invention: the system performs a direct cooling battery thermal management method, the system includes a compressor, a first direct cooling plate, a second direct cooling plate, a sixth temperature sensor, and a closing component; one end of the compressor is connected in series with a condenser, one end of the condenser is connected in series with a first temperature sensor, one end of the first temperature sensor is connected in series with a drying filter, one end of the drying filter is connected in parallel with a total control flow path, and a battery refrigeration component is provided on the upper surface of the first direct cooling plate;

[0022] Wherein, the battery refrigeration assembly includes an annular fixing plate, a plurality of battery packs are arranged inside the annular fixing plate, and cooling fins are installed between adjacent battery packs, both sides of the outer surface of the cooling fins are fixedly connected with thermally conductive insulating pads, the tops of the adjacent battery packs are fixedly connected with pole pieces, the bottoms of the outer surfaces of the plurality of battery packs are fixedly connected with a first direct cooling plate, and the top of the battery pack is provided with a second direct cooling plate for preventing the area near the battery pole ear from overheating; the pole piece, cooling fin, thermally conductive insulating pad and battery pack together form a cooling partition, and a cooling channel passing through the cooling partition is opened inside the first direct cooling plate, and the cooling channel is connected in parallel with the second direct cooling plate;

[0023] Among them, the total control flow circuit includes a first control branch, a second control branch, and a third control branch; and the total control flow circuit is used to control the on-off of the refrigeration channels of the first control branch, the second control branch, and the third control branch; and when the battery refrigeration assembly is running, at least one refrigeration channel is in a conducting state.

[0024] As a further scheme of the present invention: an evaporator is provided at one end of the first control branch, and the compressor, condenser, first temperature sensor, drying filter, first control branch and evaporator are connected to form a first refrigerant flow path; the compressor, condenser, first temperature sensor, drying filter, second control branch and first direct cooling plate are connected to form a second refrigerant flow path; the compressor, condenser, first temperature sensor, drying filter, third control branch and second direct cooling plate are connected to form a third refrigerant flow path; the closing component includes a first solenoid valve and a first electronic expansion valve; the first solenoid valve is connected between the condenser and the evaporator, and the first electronic expansion valve is connected between the first solenoid valve and the evaporator; when the battery refrigeration component executes the first refrigerant flow path, the first solenoid valve and the first electronic expansion valve are both opened.

[0025] As a further solution of the present invention: a second temperature sensor is commonly connected between the first electronic expansion valve and the evaporator; a third temperature sensor is commonly connected between the evaporator and the compressor; a fourth temperature sensor is commonly connected between the third temperature sensor and the compressor; and the first solenoid valve, the first electronic expansion valve, the second temperature sensor, the evaporator, the third temperature sensor and the fourth temperature sensor are commonly connected to form a first control branch.

[0026] As a further solution of the present invention: the closing component also includes a second solenoid valve and a second electronic expansion valve; the second solenoid valve is connected between the condenser and the first direct cooling plate, and the second electronic expansion valve is connected between the second solenoid valve and the first direct cooling plate; when the battery refrigeration component executes the second refrigerant flow path, the second solenoid valve and the second electronic expansion valve are both opened; the second electronic expansion valve and the first direct cooling plate are commonly connected with a fifth temperature sensor, and the first direct cooling plate and the compressor are commonly connected with a sixth temperature sensor; and the second solenoid valve, the second electronic expansion valve, the fifth temperature sensor, the first direct cooling plate and the sixth temperature sensor are connected to form a second control branch.

[0027] As a further solution of the present invention: the closing component also includes a third solenoid valve and a third electronic expansion valve; the third solenoid valve is connected between the condenser and the second direct cooling plate, and the third electronic expansion valve is connected between the third solenoid valve and the second direct cooling plate; when the battery refrigeration component executes the third refrigerant flow path, the third solenoid valve and the third electronic expansion valve are both opened.

[0028] As a further solution of the present invention: the third solenoid valve and the third electronic expansion valve are commonly connected through a subcooler, the third electronic expansion valve and the second direct cooling plate are commonly connected through a seventh temperature sensor, and the second direct cooling plate and the compressor are commonly connected through an eighth temperature sensor; and the third solenoid valve, the subcooler, the third electronic expansion valve, the seventh temperature sensor, the second direct cooling plate, and the eighth temperature sensor are commonly connected to form a third control branch.

[0029] Compared with the prior art, the above technical solution provided by the present invention has at least the following beneficial effects:

[0030] (1) This solution is provided with a condenser, a drying filter, and an evaporator. When in use, the first solenoid valve and the first electronic expansion valve are precisely controlled to achieve precise regulation of the refrigerant flow entering the first control branch. At the same time, the fourth temperature sensor monitors the current temperature of the cabin in real time. When the temperature exceeds the preset standard, the evaporator is further used for cooling to ensure that the cabin is within the comfortable standard temperature range.

[0031] (2) By providing components such as a second solenoid valve, a second electronic expansion valve, a fifth temperature sensor, a first straight cooling plate, and a sixth temperature sensor, when in use, if the second electronic expansion valve is fully opened and the temperature still needs to be further adjusted, the system will adjust the compressor speed to further increase the flow rate of the refrigerant flow. At this time, the fifth temperature sensor is used to monitor the temperature of the refrigerant flow through the second electronic expansion valve to ensure that the temperature is within a controllable range. Subsequently, the battery pack is cooled through the first straight cooling plate, and the refrigerant flow enters each refrigeration partition of the battery pack from the refrigeration flow channel to uniformly cool the bottom of the battery pack. By intelligently adjusting the cooling flow and path in this way, the system can efficiently respond to the cooling needs of the battery pack and ensure that the battery pack operates within the normal operating temperature range.

[0032] (3) By providing components such as a third solenoid valve, a third electronic expansion valve, a supercooler, a second direct cooling plate, a pole piece, a thermally conductive insulating pad, and cooling fins, an efficient and accurate temperature difference control effect of the battery pack is achieved by dynamically adjusting the refrigerant flow path and flow rate. Specifically, when the system detects that the temperature difference inside the battery pack exceeds 5°C, it first opens the third solenoid valve and the third electronic expansion valve to guide the refrigerant to flow through the third control branch, and further cools it through the supercooler, and then uses the second direct cooling plate to focus on cooling the top of the battery pack, especially near the battery pole ear. In order to enhance the cooling effect, the system also uses components such as pole pieces, thermally conductive insulating pads, and cooling fins to increase the heat dissipation area of ​​the battery pack, thereby improving the cooling efficiency and achieving more uniform cooling of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, further serve to explain the principles of the invention and to enable those skilled in the relevant art to make and use the invention.

[0034] Figure 1 is a schematic diagram of a thermal management system of the present invention;

[0035] Figure 2 A refrigeration circuit of the thermal management system of the present invention;

[0036] Figure 3 A supercooling circuit of the thermal management system of the present invention;

[0037] Figure 4 This is a front view of a direct-cooling battery pack cooling structure of the present invention;

[0038] Figure 5 for Figure 4 The enlarged schematic diagram at A in the middle;

[0039] Figure 6 It is a schematic diagram of the flow channel of the first straight cooling plate structure of the present invention;

[0040] Figure 7 It is a structural schematic diagram of the second direct cooling plate of the present invention;

[0041] Figure 8 It is a schematic structural diagram of the cooling fin of the present invention.

[0042] Reference numerals:

[0043] 1. Compressor; 2. Condenser; 3. Dry filter; 4. First solenoid valve; 5. First electronic expansion valve; 6. Evaporator; 7. Second solenoid valve; 8. Second electronic expansion valve; 9. First direct cooling plate; 10. Third solenoid valve; 11. Subcooler; 12. Third electronic expansion valve; 13. Second direct cooling plate; 14. First temperature sensor; 15. Second temperature sensor; 16. Third temperature sensor; 17. Fourth temperature sensor; 18. Fifth temperature sensor; 19. Sixth temperature sensor; 20. Seventh temperature sensor; 21. Eighth temperature sensor; 22. Pole piece; 23. Battery pack; 24. Annular fixing plate; 25. Thermal insulation pad; 26. Cooling fins.

[0044] As shown in the figure, in order to clearly implement the structure of the embodiment of the present invention, specific structures and devices are marked in the figure, but this is only for illustrative purposes and is not intended to limit the present invention to the specific structure, device and environment. According to specific needs, ordinary technicians in this field can adjust or modify these devices and environments. DETAILED DESCRIPTION

[0045] The following is a detailed description of a direct cooling battery thermal management method and its management system provided by the present invention in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternative methods to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0046] like Figures 1 to 8 As shown, an embodiment of the present invention provides a direct cooling battery thermal management system, comprising a compressor (1), a first direct cooling plate (9), a second direct cooling plate (13), a sixth temperature sensor (19), and a closing assembly; one end of the compressor (1) is connected in series with a condenser (2), one end of the condenser (2) is connected in series with a first temperature sensor (14), one end of the first temperature sensor (14) is connected in series with a drying filter (3), one end of the drying filter (3) is connected in parallel with a total control flow path, and a battery refrigeration assembly is provided on the upper surface of the first direct cooling plate (9);

[0047] Among them, the battery refrigeration assembly includes an annular fixing plate 24, a plurality of battery packs 23 are arranged inside the annular fixing plate 24, and cooling fins 26 are installed between adjacent battery packs 23, both sides of the outer surface of the cooling fins 26 are fixedly connected with thermally conductive insulating pads 25, the tops of adjacent battery packs 23 are fixedly connected with pole pieces 22, the bottoms of the outer surfaces of the plurality of battery packs 23 are fixedly connected with the first direct cooling plate 9, and the tops of the battery packs 23 are provided with a second direct cooling plate 13 for preventing the area near the battery pole ears from overheating; the pole pieces 22, the cooling fins 26, the thermally conductive insulating pads 25 and the battery packs 23 together form a cooling partition, and a cooling channel passing through the cooling partition is opened inside the first direct cooling plate 9, and the cooling channel is connected in parallel with the second direct cooling plate 13;

[0048] Among them, the total control flow circuit includes a first control branch, a second control branch, and a third control branch; and the total control flow circuit is used to control the on-off of the refrigeration channels of the first control branch, the second control branch, and the third control branch; and when the battery refrigeration assembly is running, at least one refrigeration channel is in a conducting state.

[0049] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8As shown, an evaporator 6 is provided at one end of the first control branch, and the compressor 1, condenser 2, first temperature sensor 14, filter drier 3, first control branch and evaporator 6 are connected to form a first refrigerant flow path; the compressor 1, condenser 2, first temperature sensor 14, filter drier 3, second control branch and first direct cooling plate 9 are connected to form a second refrigerant flow path; the compressor 1, condenser 2, first temperature sensor 14, filter drier 3, third control branch and second direct cooling plate 13 are connected to form a third refrigerant flow path; the closing component includes a first solenoid valve 4 and a first electronic expansion valve 5; the first solenoid valve 4 is connected between the condenser 2 and the evaporator 6, and the first electronic expansion valve 5 is connected between the first solenoid valve 4 and the evaporator 6; when the battery refrigeration component executes the first refrigerant flow path, the first solenoid valve 4 and the first electronic expansion valve 5 are both opened.

[0050] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 As shown, a second temperature sensor 15 is commonly connected between the first electronic expansion valve 5 and the evaporator 6; a third temperature sensor 16 is commonly connected between the evaporator 6 and the compressor 1; a fourth temperature sensor 17 is commonly connected between the third temperature sensor 16 and the compressor 1; and the first solenoid valve 4, the first electronic expansion valve 5, the second temperature sensor 15, the evaporator 6, the third temperature sensor 16 and the fourth temperature sensor 17 are commonly connected to form a first control branch.

[0051] In order to solve the problem that the heat generated inside the battery pack 23 is unevenly distributed due to the fact that the refrigerant direct cooling plate used in the existing battery pack 23 is mostly arranged on one side of the bottom of the battery, resulting in a large temperature difference between the various parts of the battery, affecting the reliability of the entire system and the long-term durability of the battery, the above technical solution is now adopted to solve the problem. The above technical solution mainly consists of a battery refrigeration component, a closing component, and a condenser 2. The entire battery refrigeration component is installed in the cabin. When the electric vehicle is started, the first temperature sensor 14 is used to detect the internal ambient temperature of the cabin to calculate the temperature difference between it and the preset standard 24°C, and the sixth temperature sensor 19 is used to detect the current maximum temperature of the battery pack 23 and calculate the temperature difference between it and the preset standard 40°C. When the cabin temperature exceeds the preset standard 24°C, the high-temperature and high-pressure refrigerant is first condensed by the condenser 2, releases heat in the condenser 2 and condenses into a liquid state, forming a high-temperature and high-pressure liquid refrigerant, and then the refrigerant passes through the drying filter 3 to remove moisture and impurities therein to ensure the stability of the system operation. Open the closing component again to allow the refrigerant flow to enter the first control branch. When the liquid refrigerant flows through the evaporator 6, it absorbs the sensible heat and latent heat in the cabin, and the internal refrigerant changes from liquid to gas. In this process, the evaporator 6 can effectively reduce the temperature of the surrounding environment and achieve a cooling effect. Similarly, when the liquid refrigerant flows through the first straight cold plate 9, it absorbs the heat generated by the battery pack 23, thereby changing from liquid to gas, which helps to maintain the battery pack 23 within a suitable operating temperature range, thereby improving the performance and life of the battery. When the temperature of the battery pack 23 is still rising, the temperature of the battery pack 23 is lowered by adjusting the flow of the refrigerant flowing through the first straight cold plate 9, and then the refrigerated air is compressed by the compressor 1, and then it is circulated through the cooling treatment of the condenser 2 again, so that the battery pack 23 operates within the preset standard temperature.

[0052] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 As shown, the closing component also includes a second solenoid valve 7 and a second electronic expansion valve 8; the second solenoid valve 7 is connected between the condenser 2 and the first straight cooling plate 9, and the second electronic expansion valve 8 is connected between the second solenoid valve 7 and the first straight cooling plate 9; when the battery refrigeration component executes the second refrigerant flow path, the second solenoid valve 7 and the second electronic expansion valve 8 are both opened; the second electronic expansion valve 8 and the first straight cooling plate 9 are commonly connected with a fifth temperature sensor 18, and the first straight cooling plate 9 and the compressor 1 are commonly connected with a sixth temperature sensor 19; and the second solenoid valve 7, the second electronic expansion valve 8, the first straight cooling plate 9 and the sixth temperature sensor 19 are connected to form a second control branch.

[0053] Since the existing refrigerant direct cooling plates are mostly arranged on one side of the bottom of the battery, it is difficult to effectively deal with the problem of uneven heat distribution generated inside the battery pack 23, resulting in the temperature of some areas being significantly higher than other areas, resulting in a large temperature difference between the various parts of the battery, affecting the reliability of the entire system and the long-term durability of the battery. Therefore, when the electric vehicle is started, the sixth temperature sensor 19 detects the current maximum temperature of the battery pack 23 and compares the current maximum temperature of the battery pack 23 with the preset standard temperature of 40°C. When the temperature of the battery pack 23 exceeds the preset standard temperature, the condenser 2 is used to perform a preliminary cooling operation on the refrigerant flow, and then the impurities in the refrigerant flow are removed through the drying filter 3, and the refrigerant flow is allowed to enter the second control branch by opening the second solenoid valve 7 and the second electronic expansion valve 8, and the battery pack 23 is cooled by the first direct cooling plate 9. In this process, the refrigerant flow enters each refrigeration partition of the battery pack 23 from the refrigeration flow channel, cools the bottom of the battery pack 23, and uses the sixth temperature sensor 19 to detect the highest temperature of the battery pack 23 after preliminary cooling. When the temperature of the battery pack 23 has not reached the preset standard temperature, the fifth temperature sensor 18 is used to calculate the difference between the current temperature and the preset temperature, and the opening of the second electronic expansion valve 8 is adjusted to increase the flow rate so that the battery pack 23 is cooled down to ensure that the temperature after cooling meets the safety standard, and then is sucked into the compressor 1 for the next cycle, further ensuring the safety when using the battery pack 23.

[0054] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 As shown, the closing component also includes a third solenoid valve 10 and a third electronic expansion valve 12; the third solenoid valve 10 is connected between the condenser 2 and the second direct cooling plate 13, and the third electronic expansion valve 12 is connected between the third solenoid valve 10 and the second direct cooling plate 13; when the battery refrigeration assembly executes the third refrigerant flow path, the third solenoid valve 10 and the third electronic expansion valve 12 are both opened.

[0055] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8As shown, the third solenoid valve 10 and the third electronic expansion valve 12 are commonly connected with a subcooler 11, the third electronic expansion valve 12 and the second direct cooling plate 13 are commonly connected with a seventh temperature sensor 20, and the second direct cooling plate 13 and the compressor 1 are commonly connected with an eighth temperature sensor 21; and the third solenoid valve 10, the subcooler 11, the third electronic expansion valve 12, the seventh temperature sensor 20, the second direct cooling plate 13, and the eighth temperature sensor 21 are connected to form a third control branch.

[0056] When it is detected that the temperature difference inside the battery pack 23 exceeds 5°C, the third solenoid valve 10 and the third electronic expansion valve 12 will be opened to allow the refrigerant flow to enter the third control branch. At this time, after the refrigerant flow passes through the cooler 11 to further reduce the temperature, the top of the battery pack 23 is cooled by the second direct cooling plate 13, so that it focuses on cooling the vicinity of the excessively high temperature of the battery pack 23. In this process, the seventh temperature sensor 20 monitors the refrigerant temperature at the entrance of the second direct cooling plate 13 in real time to ensure the cooling effect. At the same time, the heat-conducting insulation pad 25 and the cooling fin 26 are used to increase the heat dissipation area of ​​the battery pack 23, improve the synergistic effect of the cooling effect, cool the battery pack 23 more evenly, and reduce the temperature difference. In the process of cooling operation using the second direct cooling plate 13, the eighth temperature sensor 21 is used to continuously monitor the temperature difference of the battery pack 23. If the temperature difference continues to be higher than 5°C, the state of the third electronic expansion valve 12 will be checked. If it is not fully open, its opening will be increased to further increase the flow rate of the refrigerant flow and improve the cooling effect. When the temperature difference approaches the preset standard, the temperature difference is further reduced by increasing the rotation speed of the compressor 1. When the temperature difference of the battery pack 23 is finally brought back to within 5°C, the existing setting will be maintained to ensure safe operation of the battery pack 23.

[0057] A direct cooling battery thermal management method comprises the following steps:

[0058] Step 1, when the electric vehicle is started, the temperature difference between the internal environment temperature of the cabin and the preset standard of 24°C and the temperature difference between the maximum temperature of the battery pack 23 and the preset standard of 40°C are calculated respectively; when the temperature of the cabin environment exceeds the preset standard, the first solenoid valve 4 is opened to allow the refrigerant flow to enter the first control branch; the first electronic expansion valve 5 is opened, the refrigerant flow is refrigerated by the evaporator 6, and the refrigerated air is compressed by the compressor 1, and then processed by the condenser 2 again, so that the cabin reaches the preset standard; when the temperature of the battery pack 23 exceeds the preset standard, the second solenoid valve 7 is opened to allow the refrigerant flow to enter the second control branch; the second electronic expansion valve 8 is opened, the refrigerant flow is refrigerated by the first straight cold plate 9, and the refrigerated air is compressed by the compressor 1, and then processed by the condenser 2 again, so that the battery pack 23 reaches the preset standard;

[0059] Step 2, set the number of particles, each particle represents a set of control parameters, including the opening of the first electronic expansion valve 5 and the speed of the compressor 1; initialize the position and speed for each particle, where the position represents the initial value of the control parameter, and the speed represents the direction and rate of change of the control parameter; define a fitness function for evaluating the stability of the cabin temperature and energy consumption under each set of control parameters; use a temperature sensor to monitor the cabin temperature in real time and compare it with the preset comfort range of 24℃±0.5℃; when the cabin temperature exceeds the comfort range, start the particle swarm optimization algorithm; for each particle, simulate the operation according to its current control parameter value, and calculate the fitness value through the fitness function; update each The individual final solution and the global final solution of each particle are obtained; the speed and position of each particle are updated according to the individual final solution and the global final solution, that is, the value of the control parameter is adjusted, and the iteration is repeated until the preset number of iterations is reached to obtain the global final solution; according to the global final solution, the final opening value of the first electronic expansion valve 5 is obtained; if the current opening of the first electronic expansion valve 5 has not reached the final value, its opening is gradually increased until it reaches the final value; if the first electronic expansion valve 5 is fully opened, but the temperature in the cabin still needs to be further regulated, the final speed value of the compressor 1 is obtained according to the global final solution output by the particle swarm optimization algorithm; the speed of the compressor 1 is adjusted to the final value to achieve further reduction and stable control of the temperature in the cabin;

[0060] Step 3, continue to monitor the temperature difference changes inside the battery pack 23. If the temperature difference continues to be higher than 5°C, check the state of the third electronic expansion valve 12; if the third electronic expansion valve 12 is not fully open, gradually increase its opening to increase the refrigerant flow and further reduce the temperature difference.

[0061] The calculation formula of the fitness function is:

[0062] ;

[0063] in, represents the value of the fitness function, which is used to evaluate the stability of the cabin temperature and the energy consumption under the control parameters; Indicates the current cabin temperature; Indicates the current maximum temperature of the battery pack; Indicates the temperature difference inside the battery pack, that is, the difference between the highest temperature and the lowest temperature in the battery pack; and The indices representing the cabin temperature, the maximum temperature of the battery pack, and the temperature difference within the battery pack are used to adjust the sensitivity of these temperature deviations in the fitness function; The penalty coefficient for cabin temperature change is used to penalize the cabin temperature when it deviates from the preset target value. It represents the penalty coefficient of ambient temperature on energy efficiency, which is used to consider the impact of external ambient temperature on system energy efficiency; Indicates the penalty coefficient of the temperature difference inside the battery pack, which is used to penalize the situation where the temperature difference inside the battery pack deviates from the target value; Indicates the speed of the compressor in the refrigeration system; represents the opening of the electronic expansion valve (the electronic expansion valve refers to the first electronic expansion valve, the second electronic expansion valve, and the third electronic expansion valve); γ and δ represent nonlinear control parameters, which are used to adjust the influence of the compressor speed and the opening of the electronic expansion valve in the fitness function; represents the ambient temperature outside the vehicle; t represents time, which is used to consider the impact of system operation time on fitness; , Respectively represent the weight coefficients of compressor speed, electronic expansion valve opening and time, which are used to balance the importance of these factors in the fitness function;

[0064] in, Indicates the current cabin temperature The exponential form of the deviation from the preset target temperature of 24°C; Indicates the current maximum temperature of the battery pack The exponential form of the deviation from the preset standard temperature of 40°C; Indicates battery temperature difference The exponential form of the difference from the daily standard value of 5°C; represents the attenuation term with the square of cabin temperature deviation as the exponential, The penalty coefficient representing the temperature change rate is used to penalize the case where the cabin temperature deviates from the target temperature; , They represent the nonlinear control parameters of the compressor speed and the electronic expansion valve opening, respectively, where γ and δ are the corresponding exponents; Indicates the temperature outside the vehicle Impact on system energy efficiency, Represents the penalty coefficient of ambient temperature on energy efficiency; Indicates the external ambient temperature The difference from the target value of 25°C.

[0065] Among them, the speed and position of each particle are updated, and the speed update formula is:

[0066] ;

[0067] in, represents particle i at time speed; represents the velocity of particle i at time t; represents the position of particle i at time t; represents the individual final position of particle i; Indicates the final global position; , represents the acceleration constant; , represents a random number in the range [0, 1]; w represents the weight;

[0068] The update formula of position is:

[0069] ;

[0070] in, represents particle i at time location.

[0071] When the present invention is in use, first when the electric vehicle is started, the direct cooling battery thermal management system is started. The compressor 1 starts working, compressing the refrigerant into a high temperature and high pressure state, and then the refrigerant enters the condenser 2 for condensation treatment, releases heat and condenses into a liquid state, forming a high temperature and high pressure liquid refrigerant. During this process, the fourth temperature sensor 17 monitors the internal ambient temperature of the cabin in real time and compares it with the preset standard temperature range of 24±0.5℃; at the same time, the sixth temperature sensor 19 monitors the current maximum temperature of the battery pack 23 in real time and compares it with the preset standard temperature of 40℃. If the temperature inside the cabin exceeds the preset standard range, the liquid refrigerant will pass through the drying filter 3 to remove the moisture and impurities therein, and then use the evaporator 6 to cool the entire cabin, thereby ensuring the stability of the system operation. After that, the refrigerant flow will enter the total control flow path, and according to the real-time temperature and temperature difference inside the cabin, the refrigerant flow will be controlled by the closed component to enter different control branches for cooling operation.

[0072] When the temperature of the battery pack 23 is high but the temperature difference is not large, the first solenoid valve 4 and the first electronic expansion valve 5 will be opened first to allow the refrigerant to flow into the first control branch. At this time, the liquid refrigerant flows through the evaporator 6, absorbs the heat in the cabin, and changes from liquid to gas to achieve a cooling effect. The second temperature sensor 15 monitors the refrigerant temperature at the inlet of the evaporator 6 in real time to ensure the cooling effect. The refrigerant is detected by the third temperature sensor 16 and the cabin ambient temperature is monitored by the fourth temperature sensor 17 to ensure that the cabin ambient temperature after cooling meets the safety standards. The refrigerant is then sucked into the compressor 1 for the next cycle.

[0073] If the temperature of the battery pack 23 continues to rise or the temperature difference begins to increase, the system will open the second solenoid valve 7 and the second electronic expansion valve 8 to allow the refrigerant flow to enter the second control branch. At this time, the refrigerant flow passes through the subcooler 11 to further reduce the temperature, and then passes through the refrigeration flow channel inside the first straight cold plate 9 to cool the bottom of the battery pack 23. The fifth temperature sensor 18 monitors the refrigerant temperature at the inlet of the first straight cold plate 9 in real time to ensure the cooling effect before being sucked into the compressor 1 for circulation.

[0074] When the system detects that the temperature difference inside the battery pack 23 exceeds 5°C, the third solenoid valve 10 and the third electronic expansion valve 12 will be opened to allow the refrigerant flow to enter the third control branch. At this time, after the refrigerant flow passes through the supercooler 11 to further reduce the temperature, the top of the battery pack 23 is cooled by the second direct cooling plate 13, so that it focuses on cooling the vicinity of the battery pack 23 where the temperature of the pole ear is too high. In this process, the seventh temperature sensor 20 monitors the refrigerant temperature at the outlet of the second direct cooling plate 13 in real time to ensure the cooling effect. At the same time, the battery pack 23 is cooled more evenly and the temperature difference is reduced by the synergistic effect of the thermally conductive insulation pad 25 and the cooling fins 26. In the process of cooling operation using the second direct cooling plate 13, the eighth temperature sensor 21 is used to continuously monitor the temperature difference of the battery pack 23. If the temperature difference continues to be higher than 5°C, the system will check the state of the third electronic expansion valve 12. If it is not fully open, its opening will be increased to further increase the flow rate of the refrigerant flow and improve the cooling effect. When the temperature difference approaches the preset standard, the temperature difference is further reduced by increasing the speed of the compressor 1, and finally the temperature difference of the battery pack 23 returns to within 5°C. When the temperature and temperature difference of the battery pack 23 reach the preset standard, the system will gradually reduce the opening of each solenoid valve and the electronic expansion valve until they are completely closed, so that the system enters a low-power standby state or completely shuts down. At this time, the compressor 1 stops working, the refrigerant circulation stops, and the system enters energy-saving mode.

[0075] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not described in detail.

[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A direct cooling battery thermal management method, characterized in that: The following steps are involved: Step 1, when the electric vehicle is started, the temperature difference between the ambient temperature inside the cabin and a preset standard of 24°C, and the temperature difference between the maximum temperature of the battery pack (23) and a preset standard of 40°C are calculated; if the ambient temperature of the cabin exceeds 24°C, the first solenoid valve (4) is opened, the first electronic expansion valve (5) is opened, and the heat in the cabin is absorbed by the evaporator (6) so that the temperature inside the cabin reaches the preset standard; if the temperature of the battery pack (23) exceeds 40°C, the second solenoid valve (7) and the second electronic expansion valve (8) are opened, and the refrigerant flow is cooled by the first straight cold plate (9) so that the battery pack (23) reaches the preset standard; Step 2, setting the number of particles, each particle representing a set of control parameters, including the opening of the first electronic expansion valve (5) and the speed of the compressor (1); initializing the position and speed of each particle, wherein the position represents the initial value of the control parameter, and the speed represents the direction and rate of change of the control parameter; defining a fitness function for evaluating the stability of the cabin temperature and the energy consumption under each set of control parameters; using a temperature sensor to monitor the cabin temperature in real time, and comparing it with a preset comfort range of 24°C±0.5°C; when the cabin temperature exceeds the comfort range, starting the particle swarm optimization algorithm; for each particle, simulating the operation according to its current control parameter value, and calculating the fitness value through the fitness function; updating the individual final solution and the global final solution of each particle; updating the speed and position of each particle according to the individual final solution and the global final solution, that is, adjusting the value of the control parameter, and repeating the iteration until a preset number of iterations is reached to obtain the global final solution; According to the global final solution, the final opening value of the first electronic expansion valve (5) is obtained; if the current opening of the first electronic expansion valve (5) has not reached the final value, the opening is gradually increased until the final value is reached; if the first electronic expansion valve (5) is fully opened, but the temperature in the vehicle cabin still needs to be further regulated, according to the global final solution output by the particle swarm optimization algorithm, the final speed value of the compressor (1) is obtained; the speed of the compressor (1) is adjusted to the final value, so as to further reduce and stabilize the temperature in the vehicle cabin; Step 3, continue to monitor the temperature difference change inside the battery pack (23); if the temperature difference continues to be higher than 5° C., check the state of the third electronic expansion valve (12); if the third electronic expansion valve (12) is not fully open, gradually increase its opening to reduce the temperature difference; The calculation formula of the fitness function is: ； in, represents the value of the fitness function, which is used to evaluate the stability of the cabin temperature and the energy consumption under the control parameters; Indicates the current cabin temperature; Indicates the current maximum temperature of the battery pack; Indicates the temperature difference inside the battery pack, that is, the difference between the highest temperature and the lowest temperature in the battery pack; and The indices representing the cabin temperature, the maximum temperature of the battery pack, and the temperature difference within the battery pack are used to adjust the sensitivity of these temperature deviations in the fitness function; The penalty coefficient for cabin temperature change is used to penalize the cabin temperature when it deviates from the preset target value. It represents the penalty coefficient of ambient temperature on energy efficiency, which is used to consider the impact of external ambient temperature on system energy efficiency; Indicates the penalty coefficient of the temperature difference inside the battery pack, which is used to penalize the situation where the temperature difference inside the battery pack deviates from the target value; Indicates the speed of the compressor in the refrigeration system; represents the opening of the electronic expansion valve; γ and δ represent the indexes corresponding to the nonlinear control parameters, which are used to adjust the influence of the compressor speed and the opening of the electronic expansion valve in the fitness function; represents the ambient temperature outside the vehicle; t represents time, which is used to consider the impact of system operation time on fitness; , Respectively represent the weight coefficients of compressor speed, electronic expansion valve opening and time, which are used to balance the importance of these factors in the fitness function; in, Indicates the current cabin temperature The exponential form of the deviation from the preset target temperature of 24°C; Indicates the current maximum temperature of the battery pack The exponential form of the deviation from the preset standard temperature of 40°C; Indicates battery temperature difference The exponential form of the difference from the daily standard value of 5°C; represents the attenuation term with the square of cabin temperature deviation as the exponential; , They represent the nonlinear control parameters of the compressor speed and the electronic expansion valve opening respectively; Indicates the temperature outside the vehicle Impact on system energy efficiency; Indicates the external ambient temperature The difference from the target value of 25°C; Among them, the speed and position of each particle are updated, and the speed update formula is: ； in, represents particle i at time speed; represents the velocity of particle i at time t; represents the position of particle i at time t; represents the individual final position of particle i; Indicates the final global position; , represents the acceleration constant; , represents a random number in the range [0, 1]; w represents the weight; The update formula of position is: ； in, represents particle i at time location.

2. The direct cooling battery thermal management method according to claim 1, characterized in that: The specific operation process of step 3 is as follows: If it is detected that the temperature difference inside the battery pack (23) exceeds 5°C, the third solenoid valve (10) and the third electronic expansion valve (12) will be opened to optimize the temperature distribution; Continue to monitor the temperature difference change. If the temperature difference continues to be higher than 5°C, check the state of the third electronic expansion valve (12). If the third electronic expansion valve (12) is not fully open, increase the opening of the third electronic expansion valve (12) and increase the speed of the compressor (1) to reduce the temperature difference. Finally, when the temperature difference of the battery pack (23) returns to within 5°C, the existing settings will be maintained to allow the battery pack (23) to operate safely.

3. A direct cooling battery thermal management system, characterized in that: The system executes the method according to any one of claims 1 to 2, the system comprising a compressor (1), a first direct cooling plate (9), a second direct cooling plate (13), a sixth temperature sensor (19), and a closing component; one end of the compressor (1) is connected in series with a condenser (2), one end of the condenser (2) is connected in series with a first temperature sensor (14), one end of the first temperature sensor (14) is connected in series with a drying filter (3), one end of the drying filter (3) is connected in parallel with a total control flow path, and a battery refrigeration component is provided on the upper surface of the first direct cooling plate (9); The battery cooling assembly comprises an annular fixing plate (24), a plurality of battery packs (23) are arranged inside the annular fixing plate (24), and cooling fins (26) are installed between adjacent battery packs (23), both sides of the outer surface of the cooling fins (26) are fixedly connected with heat-conducting insulating pads (25), the tops of the adjacent battery packs (23) are fixedly connected with pole pieces (22), the bottoms of the outer surfaces of the plurality of battery packs (23) are fixedly connected with a first direct cooling plate (9), and the tops of the battery packs (23) are provided with a second direct cooling plate (13) for preventing the area near the battery pole ears from overheating; the pole pieces (22), the cooling fins (26), the heat-conducting insulating pads (25) and the battery packs (23) together form a cooling partition, and a cooling channel passing through the cooling partition is opened inside the first direct cooling plate (9), and the cooling channel is connected in parallel with the second direct cooling plate (13); Wherein, the total control flow path includes a first control branch, a second control branch, and a third control branch; and the total control flow path is used to control the on-off of the refrigeration channels of the first control branch, the second control branch, and the third control branch; and when the battery refrigeration assembly is running, at least one refrigeration channel is in a conducting state; An evaporator (6) is provided at one end of the first control branch, and the compressor (1), condenser (2), first temperature sensor (14), filter drier (3), first control branch and evaporator (6) are connected to form a first refrigerant flow path; the compressor (1), condenser (2), first temperature sensor (14), filter drier (3), second control branch and first direct cooling plate (9) are connected to form a second refrigerant flow path; the compressor (1), condenser (2), first temperature sensor (14), filter drier (3), third control branch and second direct cooling plate (13) are connected to form a third refrigerant flow path; the closing component comprises a first solenoid valve (4) and a first electronic expansion valve (5); the first solenoid valve (4) is connected between the condenser (2) and the evaporator (6), and the first electronic expansion valve (5) is connected between the first solenoid valve (4) and the evaporator (6); when the battery refrigeration component executes the first refrigerant flow path, the first solenoid valve (4) and the first electronic expansion valve (5) are both opened; The closing component further comprises a second solenoid valve (7) and a second electronic expansion valve (8); the second solenoid valve (7) is connected between the condenser (2) and the first direct cooling plate (9), and the second electronic expansion valve (8) is connected between the second solenoid valve (7) and the first direct cooling plate (9); when the battery refrigeration component executes the second refrigerant flow path, the second solenoid valve (7) and the second electronic expansion valve (8) are both opened; a fifth temperature sensor (18) is commonly connected between the second electronic expansion valve (8) and the first direct cooling plate (9), and a sixth temperature sensor (19) is commonly connected between the first direct cooling plate (9) and the compressor (1); and the second solenoid valve (7), the second electronic expansion valve (8), the fifth temperature sensor (18), the first direct cooling plate (9) and the sixth temperature sensor (19) are commonly connected to form a second control branch; The closing component further comprises a third solenoid valve (10) and a third electronic expansion valve (12); the third solenoid valve (10) is connected between the condenser (2) and the second direct cooling plate (13), and the third electronic expansion valve (12) is connected between the third solenoid valve (10) and the second direct cooling plate (13); when the battery refrigeration component executes the third refrigerant flow path, the third solenoid valve (10) and the third electronic expansion valve (12) are both opened.

4. A direct cooling battery thermal management system according to claim 3, characterized in that: A second temperature sensor (15) is commonly connected between the first electronic expansion valve (5) and the evaporator (6); a third temperature sensor (16) is commonly connected between the evaporator (6) and the compressor (1); a fourth temperature sensor (17) is commonly connected between the third temperature sensor (16) and the compressor (1); and the first solenoid valve (4), the first electronic expansion valve (5), the second temperature sensor (15), the evaporator (6), the third temperature sensor (16) and the fourth temperature sensor (17) are commonly connected to form a first control branch.

5. A direct cooling battery thermal management system according to claim 4, characterized in that: The third solenoid valve (10) and the third electronic expansion valve (12) are commonly connected to a subcooler (11); the third electronic expansion valve (12) and the second direct cooling plate (13) are commonly connected to a seventh temperature sensor (20); the second direct cooling plate (13) and the compressor (1) are commonly connected to an eighth temperature sensor (21); and the third solenoid valve (10), the subcooler (11), the third electronic expansion valve (12), the seventh temperature sensor (20), the second direct cooling plate (13), and the eighth temperature sensor (21) are commonly connected to form a third control branch.

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