Control method of thermal management system, thermal management system and vehicle

Abstract

The invention relates to a control method of a thermal management system, the thermal management system and a vehicle, the thermal management system comprises a cooling liquid circulation loop, and the cooling liquid circulation loop comprises a battery heat exchange loop and a driving system heat exchange loop; the control method comprises the following steps: obtaining a power battery cooling request; on the basis that the temperature of cooling liquid of a driving system heat exchange loop is smaller than the temperature of a power battery, it is determined that the driving system heat exchange loop is in a heat dissipation state, a battery heat exchange loop is controlled to be communicated with the driving system heat exchange loop, and a compressor of a heat management system is controlled to stop running. The power battery can be cooled without starting the compressor, and the situation that the compressor is used for cooling the power battery in a low-temperature environment, and consequently compressor loss is caused is avoided.

Description

Technical Field

[0001] The present disclosure relates to the technical field of vehicle thermal management, and particularly to a control method for a thermal management system, a thermal management system, and a vehicle. Background Art

[0002] With the increasing popularity of electric vehicles in China, the application of thermal management system technology is becoming more and more extensive. Currently, the cooling of power batteries is achieved by the operation of a compressor. Through the operation of the compressor, heat is "transported" from the battery to the external environment, thereby achieving battery cooling.

[0003] In fact, there are many scenarios where the power battery has a cooling requirement. It is not only required when the ambient temperature is high, but also may trigger a cooling requirement when the ambient temperature is low. For example, in the scenario of low-temperature DC fast charging, due to the large charging power, the battery generates a large amount of heat, and the temperature of the battery cells increases significantly during charging, requiring refrigeration and cooling to maintain the charging efficiency and ensure safety. However, cooling the battery in a low-temperature environment will start the compressor. When the compressor refrigerates at low temperature, the condensation pressure will drop rapidly, the intake pressure of the compressor is also low, the compressor maintains a low speed for a long time, the working load is large, and the efficiency is low. Long-term use of the compressor for refrigeration in a low-temperature environment will increase energy consumption and wear, and shorten the service life. Summary of the Invention

[0004] To solve the above technical problems, the present disclosure provides a control method for a thermal management system, a thermal management system, and a vehicle.

[0005] In a first aspect, the present disclosure provides a control method for a thermal management system. The thermal management system includes a coolant circulation loop, and the coolant circulation loop includes a battery heat exchange loop and a drive system heat exchange loop; The control method includes: Obtaining a power battery cooling request; Based on the coolant temperature of the drive system heat exchange loop being less than the temperature of the power battery, and determining that the drive system heat exchange loop is in a heat dissipation state, controlling the battery heat exchange loop to communicate with the drive system heat exchange loop, and controlling the compressor of the thermal management system to stop operating.

[0006] In some embodiments, before controlling the battery heat exchange loop to communicate with the drive system heat exchange loop, it further includes: Determining that there is no cooling or heating request in the passenger compartment.

[0007] In some embodiments, before controlling the battery heat exchange loop to communicate with the drive system heat exchange loop, it further includes: Determining that the ambient temperature is less than the coolant temperature of the drive system heat exchange loop.

[0008] In some embodiments, before controlling the battery heat exchange circuit to communicate with the drive system heat exchange circuit, it further includes: Determine that the coolant temperature of the drive system heat exchange circuit is less than the warning protection temperature of the power battery.

[0009] In some embodiments, after controlling the battery heat exchange circuit to communicate with the drive system heat exchange circuit, it further includes: Obtain the first coolant flow rate required to cool the power battery and the second coolant flow rate required to cool the motor; Determine the maximum value of the first coolant flow rate and the second coolant flow rate as the target flow rate, and control the coolant in the connected battery heat exchange circuit and drive system heat exchange circuit to flow at the target flow rate.

[0010] In some embodiments, after controlling the battery heat exchange circuit to communicate with the drive system heat exchange circuit, it further includes: Determine the ambient air volume and the estimated total air volume required to cool the power battery and the motor; Based on the estimated total air volume being greater than the ambient air volume, control the operation of the cooling fan in the drive system heat exchange circuit.

[0011] In some embodiments, controlling the operation of the cooling fan in the drive system heat exchange circuit further includes: Based on the difference between the estimated total air volume and the ambient air volume, and the corresponding relationship between the difference between the estimated total air volume and the ambient air volume and the target speed of the cooling fan, determine the target speed of the cooling fan, and control the speed of the cooling fan based on the target speed; Wherein, the corresponding relationship between the difference between the estimated total air volume and the ambient air volume and the target speed of the cooling fan can be calibrated in advance.

[0012] In some embodiments, controlling the operation of the cooling fan in the drive system heat exchange circuit includes: Obtain the target coolant temperature for cooling the power battery and the target coolant temperature for cooling the motor, and take the minimum value as the target water temperature; Based on the change of the difference between the target water temperature and the coolant temperature of the connected circuit, using the target water temperature as the closed-loop target temperature, adopt the proportional integral derivative control algorithm to determine the target speed of the cooling fan, and control the speed of the cooling fan based on the target speed.

[0013] In some embodiments, the power battery includes a plurality of battery cells; the control method further includes: Obtain the temperatures of the respective battery cells in the power battery; Determine the highest temperature among the cells as the temperature of the power battery.

[0014] In some embodiments, it further includes: Based on the coolant temperature of the drive system heat exchange circuit being greater than the temperature of the power battery, and / or determining that the drive system heat exchange circuit is not in a heat dissipation state, control the battery heat exchange circuit to disconnect from the drive system heat exchange circuit, and control the compressor of the thermal management system to operate, so as to cool or heat the power battery in the battery heat exchange circuit.

[0015] In a second aspect, the present disclosure provides a thermal management system, including: a coolant circulation circuit and a control device; The coolant circulation circuit includes a battery heat exchange circuit and a drive system heat exchange circuit; The control device is connected to the battery heat exchange circuit, the drive system heat exchange circuit, and the compressor; the control device is configured to obtain a power battery cooling request, and based on the coolant temperature of the drive system heat exchange circuit being less than the temperature of the power battery, and determining that the drive system heat exchange circuit is in a heat dissipation state, control the battery heat exchange circuit to communicate with the drive system heat exchange circuit, and control the compressor of the thermal management system to stop operating.

[0016] In a third aspect, the present disclosure provides a vehicle, including the thermal management system provided in the second aspect above.

[0017] The technical solution provided by the present disclosure has the following advantages compared with the prior art: For the control method of the thermal management system provided by the present disclosure, if a power battery cooling request is obtained, it means that the temperature of the power battery of the vehicle is relatively high and it should be cooled down. If it is determined that the coolant temperature of the drive system circuit is less than the temperature of the power battery, and it is determined that the drive system heat exchange circuit is in a heat dissipation state, then the battery heat exchange circuit can be made to communicate with the drive system heat exchange circuit, and the compressor of the thermal management system can be controlled to stop operating. At this time, the coolant of the drive system heat exchange circuit flows through the battery heat exchange circuit and exchanges heat with the power battery, taking away the heat of the power battery, and this part of the heat can be released in the drive system heat exchange circuit. Thus, the embodiments of the present disclosure can cool the power battery without starting the compressor, avoiding the situation of compressor loss when using the compressor to cool the power battery in a low-temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure.

[0019] To more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 Schematic flowchart of a control method for a thermal management system provided by an embodiment of the present disclosure; Figure 2 Schematic structural diagram of a thermal management system provided by an embodiment of the present disclosure.

[0021] Among them, 1. Battery heat exchange circuit; 2. Drive system heat exchange circuit; 3. Occupant compartment heat exchange circuit; 10. Power battery; 11. First water pump; 20. Motor; 21. Radiator; 22. Cooling fan; 23. Second water pump; 31. Condenser; 32. Heater core; 33. Heater water pump; 40. Multi-way valve. Detailed implementation manners

[0022] In order to better understand the above objects, features, and advantages of the present disclosure, the following will further describe the solutions of the present disclosure. It should be noted that, without conflict, the embodiments of the present disclosure and the features in the embodiments can be combined with each other.

[0023] Many specific details are set forth in the following description to facilitate a thorough understanding of the present disclosure, but the present disclosure may be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present disclosure, rather than all the embodiments.

[0024] An embodiment of the present disclosure provides a control method for a thermal management system, Figure 1 Schematic flowchart of a control method for a thermal management system provided by an embodiment of the present disclosure, Figure 2 Schematic structural diagram of a thermal management system provided by an embodiment of the present disclosure. Refer to Figure 1 and Figure 2 , the thermal management system includes a coolant circulation circuit, and the coolant circulation circuit includes a battery heat exchange circuit 1 and a drive system heat exchange circuit 2.

[0025] Refer to Figure 2 , the thermal management system includes a coolant circulation circuit and a refrigerant circulation circuit, Figure 2Only the coolant circulation loop is shown. The coolant circulation loop includes a battery heat exchange loop 1 and a drive system heat exchange loop 2. The coolant circulation loop drives the flow of heat or cold through the flow of coolant to complete the heat exchange of the thermal management system. In the battery heat exchange loop 1, the coolant can flow through the power battery 10 to exchange heat with the power battery 10. In the drive system heat exchange loop 2, the coolant can flow through the motor 20 to exchange heat with the motor 20. Usually, a radiator 21 is provided in the drive system heat exchange loop 2 to enable the coolant to exchange heat with the external environment. Or the drive system heat exchange loop 2 is connected to other loops for heat exchange. The refrigerant circulation loop is not shown in the drawings. The loop pipeline includes refrigerant for refrigeration or heating. The refrigerant circulation loop includes a compressor. In the prior art, usually, to start the compressor, heat exchange is carried out through the refrigerant circulation loop and the coolant circulation loop to provide the required heat or cold for the power battery.

[0026] However, in some scenarios, cooling the power battery by the compressor will damage the compressor itself. For example, in the scenario of low-temperature DC fast charging, due to the large charging power, the battery generates a large amount of heat, and the temperature of the battery rises significantly during the charging process. Refrigeration is required to maintain the charging efficiency and ensure safety. When cooling the power battery at a low ambient temperature, the compressor will be started. At low temperatures, the compressor refrigerates, and the condensation pressure will drop rapidly. The intake pressure of the compressor is also low, resulting in the compressor maintaining a low speed for a long time, with a large working load and low efficiency. Therefore, using the compressor for refrigeration in a low-temperature environment for a long time will increase energy consumption and wear, and shorten the service life.

[0027] To solve the above problems, the control method of the thermal management system includes: S110. Obtain a power battery cooling request.

[0028] When the power battery in the vehicle is in a working state, such as during the charging process, the power is relatively large and the temperature will rise. If the temperature continues to rise and the heat is not effectively released, it will affect the health state of the power battery. Therefore, it is necessary to cool the power battery in time to reduce its temperature. For example, by obtaining a power battery cooling request, it is determined that the current temperature of the power battery is too high and cooling should be carried out in time. For example, a temperature detection unit is set up to detect the temperature of the power battery in real time through the temperature detection unit. If it is determined that the temperature of the power battery exceeds the preset range, it means that the current temperature is too high, and the battery management system will send a power battery cooling request, and the control device can obtain the power battery cooling request at this time. Among them, the control device is used to control each component in the thermal management system. The temperature detection unit can be a temperature sensor, which is set on the power battery. In other scenarios, other detection devices can also be used to obtain the temperature of the power battery.

[0029] S120. When the coolant temperature of the heat exchange circuit of the drive system is lower than the temperature of the power battery and it is determined that the heat exchange circuit of the drive system is in a heat dissipation state, control the connection between the battery heat exchange circuit and the heat exchange circuit of the drive system, and control the compressor of the thermal management system to stop operating.

[0030] Exemplarily, when the heat exchange circuit of the drive system is in a heat dissipation state, the heat exchange circuit of the drive system can release heat, including releasing the heat generated by the motor in the drive heat exchange circuit. For example, it can be released to the external environment through a radiator, or dissipated to other circuits (non-battery heat exchange circuits) connected to the heat exchange circuit of the drive system, or the heat can be recycled by the system, etc. Therefore, the embodiments of the present disclosure can utilize the heat exchange circuit of the drive system to achieve the purpose of cooling the power battery in the battery heat exchange circuit. The embodiments of the present disclosure do not specifically limit how the heat exchange circuit of the drive system dissipates heat, and it can be designed according to actual requirements and structures.

[0031] First, obtain the coolant temperature of the heat exchange circuit of the drive system and the temperature of the power battery. If the coolant temperature of the heat exchange circuit of the drive system is lower than the temperature of the power battery, the coolant in the heat exchange circuit of the drive system can exchange heat with the power battery and take away the heat of the power battery. This avoids reverse heating of the power battery after the heat exchange circuit of the drive system is connected to the battery heat exchange circuit. At the same time, it is necessary to determine that the heat exchange circuit of the drive system is in a heat dissipation state, so that the coolant in the heat exchange circuit of the drive system can release the heat of the power battery carried and reduce its own temperature, avoiding reverse heating of the coolant temperature in the heat exchange circuit of the drive system by the ambient temperature and achieving the cooling requirement. For example, the radiator of the heat exchange circuit of the drive system exchanges heat with the external environment, or the heat is recycled by the system, etc., to reduce its own temperature.

[0032] Therefore, referring to Figure 2 , control the connection between the battery heat exchange circuit 1 and the heat exchange circuit 2 of the drive system. The coolant in the heat exchange circuit 2 of the drive system can flow into the battery heat exchange circuit 1, flow through the power battery 10, and the coolant with a lower temperature can take away the heat of the power battery with a higher temperature and return to the heat exchange circuit 2 of the drive system. And because the heat exchange circuit 2 of the drive system is in a heat dissipation state, the heat of the power battery can be released to achieve the purpose of cooling the power battery. When controlling the connection between the battery heat exchange circuit 1 and the heat exchange circuit 2 of the drive system, it is also necessary to control the compressor of the thermal management system to stop operating to avoid using the compressor for refrigeration in a low-temperature environment, increasing the energy consumption and wear of the compressor.

[0033] Optionally, the temperature difference between the temperature of the power battery and the temperature of the coolant in the heat exchange circuit of the drive system is greater than the first calibrated temperature difference. The first calibrated temperature difference is the calibrated quantity corresponding to the cell with the highest temperature among the cells that cool the power battery. At this calibrated quantity, the coolant can meet the requirement of cooling the power battery and cool down the power battery. The higher the temperature value of the highest-temperature cell, the greater the battery cooling load, and the greater the first calibrated temperature difference is required to meet the battery cooling requirement. The first calibrated temperature difference can be obtained through pre-experiment calibration. During actual application, it can be directly determined based on the temperature of the power battery and the calibration result.

[0034] Optionally, referring to Figure 2 , a multi-way valve 40 is provided between the battery heat exchange circuit 1 and the drive system heat exchange circuit 2, and the battery heat exchange circuit 1 and the drive system heat exchange circuit 2 can be connected by controlling the multi-way valve 40.

[0035] For the control method of the thermal management system provided by the present disclosure, if a power battery cooling request is obtained, it means that the temperature of the power battery of the vehicle is relatively high and it should be cooled down. If it is determined that the temperature of the coolant in the drive system circuit is lower than the temperature of the power battery and it is determined that the drive system heat exchange circuit is in a heat dissipation state, the battery heat exchange circuit can be connected to the drive system heat exchange circuit, and the compressor of the thermal management system can be controlled to stop running. At this time, the coolant in the drive system heat exchange circuit flows through the battery heat exchange circuit and exchanges heat with the power battery, taking away the heat of the power battery, and this part of the heat can be released in the drive system heat exchange circuit. Thus, the embodiment of the present disclosure can cool the power battery without starting the compressor, avoiding the situation of compressor loss caused by using the compressor to cool the power battery in a low-temperature environment. And without enabling the use of the compressor, the system energy consumption is reduced, and at the same time, the vehicle noise level is reduced.

[0036] In some embodiments, before controlling the connection between the battery heat exchange circuit and the drive system heat exchange circuit, it further includes: Determining that there is no cooling or heating request in the passenger compartment.

[0037] Exemplarily, referring to Figure 2, the coolant circulation loop of the thermal management system further includes an occupant compartment heat exchange loop 3. By driving the circulation of heat or cold by the coolant, the heat exchange of the occupant compartment is realized, and the purpose of cooling or heating the occupant compartment is achieved. When the occupant compartment exchanges heat, a large amount of heat or cold is required. It is impossible to meet the demand or the effect is poor only by exchanging heat with the external environment. The coolant in the occupant compartment heat exchange loop 3 needs to exchange cold or heat with the refrigerant circulation loop. Therefore, a compressor needs to be used. However, the purpose of the embodiments of the present disclosure is to connect the battery heat exchange loop with the drive system heat exchange loop, and use the method of exchanging heat between the power battery and the environment to cool the power battery to avoid using a compressor. Therefore, it is necessary to determine whether there is a cooling or heating request for the occupant compartment. If it is determined that there is no cooling or heating request for the occupant compartment, the above operations can be continued, controlling the connection between the battery heat exchange loop and the drive system heat exchange loop, and controlling the compressor to stop running. In this way, it will not affect the occupant compartment and can ensure the cooling effect of the power battery.

[0038] It should be noted that the embodiments of the present disclosure do not limit how to obtain the cooling request or heating request of the occupant compartment. The temperature of the occupant compartment can be detected by a temperature detection unit, or other methods can be used, which can be selected according to actual needs.

[0039] In some embodiments, determining that the drive system heat exchange loop is in a heat dissipation state includes: Determining that the ambient temperature is lower than the coolant temperature of the drive system heat exchange loop.

[0040] Exemplarily, there are various ways to make the drive system heat exchange loop in a heat dissipation state. For example, the coolant in the drive system heat exchange loop exchanges heat with the external environment through a radiator. The coolant in the drive system heat exchange loop flows into the battery heat exchange loop, exchanges heat with the power battery, and takes away the heat of the power battery. At this time, the coolant temperature of the drive system heat exchange loop rises, and it is necessary to exchange heat with the environment through the radiator of the drive system heat exchange loop to lower its own temperature. Based on this, the ambient temperature should be lower than the coolant temperature of the drive system heat exchange loop to release the heat in the drive system heat exchange loop to the environment, lower the coolant temperature, and avoid the ambient temperature from reversely heating the coolant temperature in the drive system heat exchange loop to meet the cooling requirement.

[0041] Further, determining that the ambient temperature is lower than the target coolant temperature of the power battery.

[0042] When the coolant temperature in the heat exchange circuit of the drive system is lower than the temperature of the power battery, it has a certain cooling effect. However, the power battery has a target coolant temperature, and when the coolant temperature in the heat exchange circuit of the drive system meets the target coolant temperature, the cooling effect is optimal. At this time, it is necessary to determine that the ambient temperature is lower than the target coolant temperature of the power battery, and then control the connection between the battery heat exchange circuit and the drive system heat exchange circuit, and control the compressor to stop running.

[0043] Optionally, the temperature difference between the target coolant temperature of the power battery and the ambient temperature is higher than the second calibrated temperature difference. The second calibrated temperature difference is the calibrated quantity corresponding to the cell with the highest temperature among the cells for cooling the power battery. For example, the second calibrated temperature difference is 6 °C. At this calibrated quantity, the ambient temperature can meet the requirements for cooling the power battery. The larger the maximum cell temperature value, the greater the battery cooling load, and the larger the second calibrated temperature difference is required to meet the battery cooling requirements. The second calibrated temperature difference can be obtained through pre-experiment calibration, and in actual application, it can be directly determined based on the temperature of the power battery and the calibration result.

[0044] In summary, the temperature of the power battery is higher than the coolant temperature in the heat exchange circuit of the drive system, and the coolant temperature in the heat exchange circuit of the drive system is higher than the ambient temperature, so as to meet the cooling requirements of the embodiments of the present disclosure. Preferably, the coolant temperature in the heat exchange circuit of the drive system meets the target coolant temperature of the power battery.

[0045] Optionally, in some application scenarios, to determine that the drive system heat exchange circuit is in a heat dissipation state, other methods can also be used. For example, the heat in the drive system heat exchange circuit is recovered and reused by the system, or the drive system heat exchange circuit is connected to other circuits (non-battery heat exchange circuits), which can cool the coolant temperature in the drive system heat exchange circuit, etc. The above structures and conditions can all make the drive system heat exchange circuit in a heat dissipation state, and can be specifically set according to actual needs.

[0046] In some embodiments, before controlling the connection between the battery heat exchange circuit and the drive system heat exchange circuit, it further includes: Determine that the coolant temperature in the drive system heat exchange circuit is lower than the warning protection temperature of the power battery.

[0047] The drive system heat exchange circuit also includes a motor, which generates heat during operation. Therefore, the temperature of the coolant in the drive system heat exchange circuit may also be relatively high. Even if the temperature of the coolant in the drive system heat exchange circuit is lower than that of the power battery, the coolant temperature is still relatively high, and flowing through the power battery will affect the life of the power battery. Therefore, in order to ensure the safety of the power battery, it is also necessary to determine the relationship between the coolant temperature in the drive system heat exchange circuit and the warning protection temperature of the power battery. For example, the warning protection temperature is 45°C. If the coolant temperature in the drive system heat exchange circuit is greater than the warning protection temperature of the power battery, the coolant temperature is too high, which will affect the health of the power battery, and the method of connecting the battery heat exchange circuit and the drive system heat exchange circuit cannot be used to cool the power battery. And determining that the coolant temperature in the drive system heat exchange circuit is less than the warning protection temperature of the power battery means that the coolant temperature will not damage the power battery, and the method of connecting the battery heat exchange circuit and the drive system heat exchange circuit can be used to cool the power battery.

[0048] In some embodiments, after controlling the connection between the battery heat exchange circuit and the drive system heat exchange circuit, it further includes: Obtain the first coolant flow rate required to cool the power battery and the second coolant flow rate for cooling the motor; Determine the maximum value of the first coolant flow rate and the second coolant flow rate as the target flow rate, and control the coolant in the connected battery heat exchange circuit and drive system heat exchange circuit to flow at the target flow rate.

[0049] Exemplarily, in order to improve the cooling rate, the flow rate of the coolant in the battery heat exchange circuit and the drive system heat exchange circuit can be controlled to adjust the cooling speed by controlling the coolant flow rate. Specifically, the first coolant flow rate corresponding to the power battery at different temperatures and the second coolant flow rate corresponding to the motor at different temperatures are obtained in advance. The motor cooling mentioned here refers to the combined cooling of the motor body and the motor controller. After connecting the battery heat exchange circuit and the drive system heat exchange circuit, the coolant flow rate at each position is the same. Since the greater the coolant flow rate, the stronger the heat exchange capacity of the coolant, that is, the better the cooling effect, in order to ensure that the cooling requirements of the power battery and the motor can be met, the maximum value of the first coolant flow rate and the second coolant flow rate is determined as the target flow rate, that is, control the coolant in the connected battery heat exchange circuit and drive system heat exchange circuit to flow at the target flow rate. The coolant flowing at this target flow rate can meet the cooling requirements of the power battery and the motor.

[0050] Among them, the first coolant flow rate corresponding to the power battery at different temperatures can be obtained in advance through experiments. Similarly, the second coolant flow rate corresponding to the motor at different temperatures can be obtained in advance through experiments.

[0051] Optionally, referring to Figure 2 , the battery heat exchange circuit 1 includes a first water pump 11, and the drive system heat exchange circuit 2 includes a second water pump 23. There is a corresponding relationship between the flow rate of the coolant and the rotational speed of the water pump. The faster the rotational speed of the water pump, the greater the flow rate of the coolant. Therefore, by controlling the rotational speed of the first water pump 11 and / or the second water pump 23, a target flow rate can be obtained.

[0052] It should be noted that the embodiments of the present disclosure do not specifically limit how to achieve the flow of the coolant at the target flow rate in the heat exchange circuit. The above embodiments are only an optional implementation manner.

[0053] In some embodiments, after controlling the battery heat exchange circuit to communicate with the drive system heat exchange circuit, it further includes: Determining the ambient air volume and the estimated total air volume required to cool the power battery and the motor; Based on the estimated total air volume being greater than the ambient air volume, controlling the operation of the cooling fan in the drive system heat exchange circuit.

[0054] Exemplarily, the air volume also has a certain influence on the heat dissipation effect of the coolant in the drive system heat exchange circuit, that is, it affects the cooling effect of the power battery. The greater the air volume, the better the heat dissipation effect, and the smaller the air volume, the relatively poorer the heat dissipation effect. The coolant in the drive system heat exchange circuit can exchange heat with the environment through the radiator, and there is natural wind in the external environment. The air volume of the natural wind is affected by the weather conditions and the vehicle speed. Under the condition of a certain weather condition, the greater the vehicle speed, the greater the air volume. Thus, the ambient air volume can be determined based on the weather conditions and the vehicle speed. In addition, the temperature of the power battery and the motor can also be obtained to determine the estimated total air volume required to cool the two. For example, by pre-calibrating the corresponding relationship between the temperature of the power battery and the motor and the estimated total air volume, and then determining the corresponding estimated total air volume according to the temperature of the power battery and the motor.

[0055] If the estimated total air volume is greater than the ambient air volume, it means that the current ambient air volume cannot independently provide the air volume required to cool the power battery and the motor. The cooling fan in the drive system heat exchange circuit can be controlled to operate to provide a compensating air volume to achieve the cooling purpose. For example, referring to Figure 2 , the coolant circulation circuit of the thermal management system further includes a cooling fan 22, and the cooling fan 22 can increase the heat dissipation speed of the coolant in the drive system heat exchange circuit 2 to the environment.

[0056] If the estimated total air volume is less than the ambient air volume, it means that the current ambient air volume can provide the air volume required to cool the power battery and the motor, and there is no need to control the operation of the cooling fan in the drive system heat exchange circuit to reduce the system energy consumption.

[0057] It should be noted that for a determined type of cooling fan, the corresponding relationship between the air volume and the fan speed is determined. In addition, the corresponding relationship between the vehicle speed and the ambient air volume is also related to the vehicle model and can be determined through air volume tests.

[0058] In some embodiments, controlling the operation of the cooling fan in the heat exchange circuit of the drive system further includes: Based on the difference between the estimated total air volume and the ambient air volume, and the corresponding relationship between the difference between the estimated total air volume and the ambient air volume and the target speed of the cooling fan, determine the target speed of the cooling fan, and control the speed of the cooling fan based on the target speed; Among them, the corresponding relationship between the difference between the estimated total air volume and the ambient air volume and the target speed of the cooling fan can be calibrated in advance.

[0059] Specifically, different speeds of the cooling fan result in different air volumes. The faster the speed of the cooling fan, the greater the air volume generated. And based on the difference between the estimated total air volume and the ambient air volume, the air volume provided by the cooling fan that needs to be compensated can be determined. Calibrate the corresponding relationship between the difference and the target speed of the cooling fan in advance, and then directly look up the table based on the difference between the estimated total air volume and the ambient air volume, and the corresponding relationship between the difference between the estimated total air volume and the ambient air volume and the target speed of the cooling fan to determine the target speed of the cooling fan. Further, control the cooling fan to operate at the target speed to provide a compensated air volume for the cooling process.

[0060] In some embodiments, controlling the operation of the cooling fan in the heat exchange circuit of the drive system includes: Obtain the target coolant temperature for cooling the power battery and the target coolant temperature for cooling the motor, and take the minimum value as the target water temperature; Based on the change of the difference between the target water temperature and the coolant temperature in the connected circuit, using the target water temperature as the closed-loop target temperature, adopt the proportional-integral-derivative control algorithm to determine the target speed of the cooling fan, and control the speed of the cooling fan based on the target speed.

[0061] Specifically, the speed of the cooling fan can also be precisely controlled in a closed loop using the proportional-integral-derivative control algorithm. First, obtain the target coolant temperature for cooling the power battery and the target coolant temperature for cooling the motor, and take the minimum value as the target water temperature. Here, the minimum value refers to the lower target coolant temperature to ensure that both the power battery and the motor can achieve the required cooling effect.

[0062] After the battery heat exchange circuit and the drive system heat exchange circuit are connected, the temperature of the coolant at each position in the circuit is the same, so it is uniformly referred to as the circuit coolant temperature. As the cooling fan runs and the cooling time increases, the circuit coolant temperature will gradually decrease, and the temperature difference from the target water temperature changes continuously. To improve the refinement of the cooling process, closed-loop regulation can be adopted to adjust the speed of the cooling fan to change the compensation air volume. For example, when the temperature difference increases, the speed of the cooling fan can be increased to increase the compensation air volume; when the temperature difference decreases, the speed of the cooling fan can be decreased to reduce the compensation air volume. For example, with the target water temperature as the closed-loop target temperature, based on the change of the difference between the target water temperature and the circuit coolant temperature after connection, the proportional-integral-derivative control algorithm is used to determine the target speed of the cooling fan, and the cooling fan is controlled to run at this speed, so as to achieve the purpose of adjusting the compensation air volume.

[0063] Adopting the proportional-integral-derivative control algorithm to adjust the air volume can improve the accuracy of control and the cooling effect, and timely adjusting the speed of the cooling fan can also reduce the system power consumption to a certain extent.

[0064] It should be noted that the specific values of the control parameters (proportional coefficient, integral coefficient, and derivative coefficient) of the proportional-integral-derivative control algorithm are closely related to the physical system and need to be determined through bench and vehicle calibration.

[0065] In some embodiments, the power battery includes a plurality of battery cells; the control method further includes: Obtain the temperature of each battery cell in the power battery; Determine the highest temperature among the battery cells as the temperature of the power battery.

[0066] Exemplarily, the power battery provided by the embodiments of the present disclosure includes a plurality of battery cells, and the temperatures of different battery cells are different. Through the temperature acquisition unit, the temperature of each battery cell in the power battery can be obtained, and the highest temperature among the battery cells is determined as the temperature of the power battery. The temperature of the power battery mentioned in the embodiments of the present disclosure can be understood as the temperature corresponding to the battery cell with the highest temperature in the power battery. Taking this as the temperature of the power battery can avoid the situation that the coolant cannot cool some battery cells and ensure the overall cooling effect of the power battery.

[0067] It should be noted that the temperature acquisition unit can be a temperature sensor, which is arranged on the surface of each battery cell to obtain the temperature of each battery cell, or other acquisition devices, and the embodiments of the present disclosure do not limit this. Considering the safety of the power battery, the obtained battery cell temperatures can also be screened, for example, judging whether the highest temperature of the battery cell belongs to the normal range, etc.

[0068] In some embodiments, it further includes: Based on the coolant temperature of the drive system heat exchange circuit being greater than the temperature of the power battery, and / or determining that the drive system heat exchange circuit is not in a heat dissipation state, control the battery heat exchange circuit to disconnect from the drive system heat exchange circuit, and control the compressor of the thermal management system to operate so as to cool or heat the power battery in the battery heat exchange circuit.

[0069] If the coolant temperature of the drive system heat exchange circuit is greater than the temperature of the power battery, at this time, the coolant in the drive system heat exchange circuit cannot take away the heat of the power battery. Therefore, the power battery cannot be cooled by the way of connecting the battery heat exchange circuit and the drive system heat exchange circuit. At this time, control the disconnection of the two circuits. If the drive system heat exchange circuit is not in the heat dissipation device, the drive system heat exchange circuit cannot release the heat of the power battery and cannot cool the power battery. For example, if the ambient temperature is greater than the coolant temperature of the drive system heat exchange circuit, the ambient temperature cannot take away the heat of the power battery carried by the coolant in the drive system heat exchange circuit. Therefore, the power battery cannot be cooled by the way of connecting the battery heat exchange circuit and the drive system heat exchange circuit. At this time, control the disconnection of the two circuits. Therefore, when at least one of the above conditions is met, the battery heat exchange circuit and the drive system heat exchange circuit can be controlled to disconnect, and the compressor of the thermal management system can be controlled to operate. For example, control the multi-way valve to disconnect the connection between the battery heat exchange circuit and the drive system heat exchange circuit, and control the compressor of the thermal management system to operate. Adopt the way of heat exchange between the refrigerant circulation circuit and the battery heat exchange circuit at the heat exchanger so as to cool or heat the power battery in the battery heat exchange circuit.

[0070] Optionally, if the motor and / or the passenger compartment also have cooling or heating requirements, the drive system heat exchange circuit and / or the passenger compartment heat exchange circuit can be controlled to connect with the battery heat exchange circuit through the multi-way valve. That is, the above embodiments only represent the corresponding operations in the case where the power battery needs to be cooled and the coolant temperature of the drive system heat exchange circuit is greater than the temperature of the power battery.

[0071] The embodiment of the present disclosure also provides a thermal management system, including: a coolant circulation circuit and a control device.

[0072] The coolant circulation circuit includes a battery heat exchange circuit and a drive system heat exchange circuit.

[0073] The control device is connected to the battery heat exchange circuit, the drive system heat exchange circuit and the compressor; the control device is used to obtain a power battery cooling request, and based on the coolant temperature of the drive system heat exchange circuit being less than the temperature of the power battery, and determining that the drive system heat exchange circuit is in a heat dissipation state, control the battery heat exchange circuit to connect with the drive system heat exchange circuit, and control the compressor of the thermal management system to stop operating.

[0074] Exemplarily, Figure 2 , Figure 2The provided thermal management system only shows the coolant circulation loop and does not show the refrigerant circulation loop and the control device. Among them, the coolant circulation loop includes a battery heat exchange loop 1 and a drive system heat exchange loop 2. The battery heat exchange loop 1 includes a power battery 10 and a first water pump 11, and the drive system heat exchange loop 2 includes a motor 20, a radiator 21, a cooling fan 22, and a second water pump 23. The refrigerant circulation loop includes a compressor for circulating refrigeration.

[0075] The control device is connected to the battery heat exchange loop 1, the drive system heat exchange loop 2, and the compressor. Here, the control device is electrically connected to each structure in the battery heat exchange loop 1 and each structure in the drive system heat exchange loop 2. For example, the control device is electrically connected to the power battery 10, the first water pump 11, the motor 20, the radiator 21, the cooling fan 22, and the second water pump 23, etc., to achieve the function of controlling the above structures.

[0076] Specifically, the control device can also obtain a power battery cooling request, such as obtaining the temperature of the power battery or obtaining a power battery request sent by the battery management system. The embodiments of the present disclosure do not limit this. After obtaining the power battery cooling request, based on the fact that the coolant temperature of the drive system heat exchange loop is lower than the temperature of the power battery and it is determined that the drive system heat exchange loop is in a heat dissipation state, the control device controls the battery heat exchange loop to communicate with the drive system heat exchange loop and controls the compressor of the thermal management system to stop operating.

[0077] The coolant of the drive system heat exchange loop flows through the battery heat exchange loop and exchanges heat with the power battery to take away the heat of the power battery. Since the drive system heat exchange loop is in a heat dissipation state, the heat of the power battery carried by the coolant can be released in the drive system heat exchange loop, for example, released to the external environment. Thus, the embodiments of the present disclosure can cool the power battery without starting the compressor, avoiding the situation of compressor loss when using the compressor to cool the power battery in a low-temperature environment. And without using the compressor, the system energy consumption is reduced, and at the same time, the vehicle noise level is reduced.

[0078] Optionally, the coolant circulation loop further includes a passenger compartment heat exchange loop 3. The passenger compartment heat exchange loop 3 includes a condenser 31, a heater core 32, and a heater water pump 33. Among them, the battery heat exchange loop 1, the drive system heat exchange loop 2, and the passenger compartment heat exchange loop 3 are all connected to a multi-way valve 40. By controlling the multi-way valve 40, any of the above loops can be made to communicate with each other.

[0079] The embodiments of the present disclosure also provide a computer-readable storage medium with a computer program stored thereon. When the computer program is executed by a processor, the steps of the control method of the thermal management system described in any of the above embodiments are implemented.

[0080] It should be noted that examples of readable storage media include, but are not limited to, systems, devices, or components of electricity, magnetism, optics, electromagnetic, infrared, or semiconductors, or any combination of the above. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), electrically programmable read-only memory (EPROM), optical fibers, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this document, a readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, device, or component.

[0081] The storage medium provided by the above embodiments of the present disclosure and the control method of the thermal management system provided by the embodiments of the present disclosure are based on the same inventive concept and have the same beneficial effects as the methods adopted, run, or implemented by the application programs or instructions stored therein.

[0082] The embodiments of the present disclosure also provide a vehicle, which includes any one of the thermal management systems provided by the embodiments of the present disclosure and has the same or corresponding beneficial effects. To avoid repetition, details are not described herein again.

[0083] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including", or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0084] The above are only specific embodiments of the present disclosure, enabling those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments described herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a thermal management system, characterized in that, The thermal management system includes a coolant circulation loop, and the coolant circulation loop includes a battery heat exchange loop and a drive system heat exchange loop; The control method includes: Obtaining a cooling request for the power battery; Based on that the coolant temperature of the drive system heat exchange loop is lower than the temperature of the power battery and it is determined that the drive system heat exchange loop is in a heat dissipation state, controlling the battery heat exchange loop to communicate with the drive system heat exchange loop, and controlling the compressor of the thermal management system to stop operating.

2. The control method according to claim 1, characterized in that Before controlling the battery heat exchange loop to communicate with the drive system heat exchange loop, it further includes: Determining that there is no cooling or heating request in the passenger compartment.

3. The control method according to claim 1, wherein Determining that the drive system heat exchange loop is in a heat dissipation state includes: Determining that the ambient temperature is lower than the coolant temperature of the drive system heat exchange loop.

4. The control method according to claim 1, characterized in that Before controlling the battery heat exchange loop to communicate with the drive system heat exchange loop, it further includes: Determining that the coolant temperature of the drive system heat exchange loop is lower than the warning protection temperature of the power battery.

5. The control method according to claim 1, characterized in that After controlling the battery heat exchange loop to communicate with the drive system heat exchange loop, it further includes: Obtaining the first coolant flow rate required to cool the power battery and the second coolant flow rate required to cool the motor; Determining the maximum value of the first coolant flow rate and the second coolant flow rate as the target flow rate, and controlling the coolant in the connected battery heat exchange loop and drive system heat exchange loop to flow at the target flow rate.

6. The control method according to claim 1, wherein After controlling the battery heat exchange loop to communicate with the drive system heat exchange loop, it further includes: Determining the ambient air volume and the estimated total air volume required to cool the power battery and the motor; Based on that the estimated total air volume is greater than the ambient air volume, controlling the cooling fan in the drive system heat exchange loop to operate.

7. The control method according to claim 6, characterized in that, Controlling the cooling fan in the drive system heat exchange loop to operate further includes: Based on the difference between the estimated total air volume and the ambient air volume and the corresponding relationship between the difference between the estimated total air volume and the ambient air volume and the target speed of the cooling fan, determining the target speed of the cooling fan, and controlling the speed of the cooling fan based on the target speed; Wherein, the corresponding relationship between the difference between the estimated total air volume and the ambient air volume and the target speed of the cooling fan can be calibrated in advance.

8. The control method according to claim 6, characterized in that, Controlling the cooling fan in the drive system heat exchange loop to operate includes: Obtaining the target coolant temperature for cooling the power battery and the target coolant temperature for cooling the motor, and taking the minimum value as the target water temperature; Based on the change of the difference between the target water temperature and the coolant temperature of the connected loop, using the target water temperature as the closed-loop target temperature, adopting a proportional-integral-derivative control algorithm to determine the target speed of the cooling fan, and controlling the speed of the cooling fan based on the target speed.

9. The control method of the thermal management system according to claim 1, wherein The power battery includes a plurality of battery cells; the control method further includes: Obtaining the temperatures of the respective battery cells in the power battery; Determining the highest temperature among the battery cells as the temperature of the power battery.

10. The control method according to claim 1, wherein It further includes: Based on the coolant temperature of the heat exchange circuit of the drive system being greater than the temperature of the power battery, and / or determining that the heat exchange circuit of the drive system is not in a heat dissipation state, control the disconnection of the battery heat exchange circuit from the heat exchange circuit of the drive system, and control the compressor of the thermal management system to operate so as to cool or heat the power battery in the battery heat exchange circuit.

11. A thermal management system, characterized in that, Comprising: a coolant circulation circuit and a control device; the coolant circulation circuit includes a battery heat exchange circuit and a heat exchange circuit of the drive system; the control device is connected to the battery heat exchange circuit, the heat exchange circuit of the drive system, and the compressor; the control device is configured to obtain a power battery cooling request, and based on the coolant temperature of the heat exchange circuit of the drive system being less than the temperature of the power battery and determining that the heat exchange circuit of the drive system is in a heat dissipation state, control the connection of the battery heat exchange circuit to the heat exchange circuit of the drive system, and control the compressor of the thermal management system to stop operating.

12. A vehicle, characterized in that, Comprising the thermal management system according to claim 11.

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