Battery cooling control method in driving process

Abstract

The invention provides a battery cooling control method in a driving process, which belongs to the technical field of battery control and comprises the following steps: acquiring the real-time temperature of a battery pack; the real-time temperature of the battery pack is compared with the preset maximum limit value of the optimal working range, the difference value of the real-time temperature of the battery pack and the environment temperature is compared with the preset temperature difference threshold value, and the cooling requirement of the battery pack is determined; according to the determined cooling requirement, at least one cooling loop is controlled to operate; and the battery pack is cooled through the cooling loop which is controlled to operate, so that the temperature of the battery pack is maintained within the optimal working range. By accurately controlling the opening, closing and operating parameters of each loop, the temperature of the battery pack is quickly and efficiently adjusted, the battery is ensured to always work within the optimal temperature range, the performance of the battery is improved, and the service life of the battery is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of battery control, and in particular to a battery cooling control method during driving. Background Art

[0002] Battery pack temperature control is a critical factor in the performance and lifespan of electric vehicles (EVs), but it faces complex and ever-changing operating environments and load conditions. Precisely regulating battery temperature under varying operating conditions to consistently maintain it within the optimal operating range presents a significant challenge. Traditional single cooling methods struggle to adapt to diverse heat dissipation requirements, easily resulting in insufficient or excessive cooling, impacting battery performance. Furthermore, frequent startups and shutdowns of the cooling system increase energy consumption and component wear. Furthermore, uneven temperature distribution within the battery pack makes localized overheating difficult to effectively address. In high-temperature environments, the cooling system's limited heat dissipation capacity makes it difficult to quickly reduce battery temperature. Conversely, in low-temperature environments, overcooling can reduce battery activity. Intelligently determining cooling needs based on real-time operating conditions, flexibly allocating multiple cooling resources, and achieving precise temperature control are pressing technical challenges. This not only impacts battery life and safety but also directly affects vehicle range and charging efficiency. Therefore, developing an intelligent temperature control system that can adapt to complex operating conditions and balance cooling efficiency with energy consumption is crucial for improving the overall performance of EVs. Summary of the Invention

[0003] The present invention provides a battery cooling control method during driving, which mainly includes: Obtaining the real-time temperature of the battery pack; determining the cooling requirement of the battery pack based on comparing the real-time temperature of the battery pack with a maximum limit of a preset optimal operating range, and comparing the difference between the real-time temperature of the battery pack and the ambient temperature with a preset temperature difference threshold; controlling the operation of at least one cooling circuit based on the determined cooling requirement, wherein the cooling circuit includes a refrigerant circuit consisting of a condenser, an electric air-conditioning compressor, an electronic expansion valve, and a battery cooler; a first liquid circuit consisting of the battery cooler, a battery pack water pump, and the battery pack; and a second liquid circuit consisting of the battery pack water pump, the battery pack, an electronic shut-off valve, and a radiator; cooling the battery pack through the controlled operation of the cooling circuits to maintain the temperature of the battery pack within the optimal operating range. Furthermore, controlling the operation of at least one cooling circuit based on the determined cooling requirement includes: if the real-time temperature of the battery pack exceeds the maximum limit of the optimal operating range and the difference between the real-time temperature of the battery pack and the ambient temperature is greater than the preset temperature difference threshold, operating the first liquid circuit and the second liquid circuit. Furthermore, operating the first and second liquid circuits includes: opening the electronic shutoff valve; driving the liquid in the first and second liquid circuits to flow via the battery pack water pump; and dissipating heat from the liquid in the second liquid circuit to the air via the radiator. Furthermore, if the real-time temperature of the battery pack still cannot be effectively reduced, the refrigerant circuit is operated simultaneously with the first and second liquid circuits. Furthermore, operating the refrigerant circuit simultaneously with the first and second liquid circuits includes: circulating the refrigerant in the refrigerant circuit via the electric air-conditioning compressor; regulating the refrigerant flow rate via the electronic expansion valve; and exchanging heat between the refrigerant and the liquid in the first liquid circuit via the battery cooler. Furthermore, if the difference between the real-time temperature of the battery pack and the ambient temperature is not greater than a preset temperature difference threshold during the simultaneous operation of the refrigerant circuit, the first and second liquid circuits, the electronic shutoff valve is closed, and only the refrigerant circuit and the first liquid circuit are operated. Furthermore, the operation of at least one cooling circuit is controlled according to the determined cooling demand, including: if the real-time temperature of the battery pack exceeds the maximum limit of the optimal operating range, and the difference between the real-time temperature of the battery pack and the ambient temperature is not greater than the preset temperature difference threshold, then the refrigerant circuit and the first liquid circuit are operated.Furthermore, the operation of the refrigerant circuit and the first liquid circuit includes: closing the electronic shut-off valve; circulating the refrigerant in the refrigerant circuit through the electric air-conditioning compressor; regulating the flow rate of the refrigerant through the electronic expansion valve; and exchanging heat between the refrigerant and the liquid in the first liquid circuit through the battery cooler.

[0004] The technical solution provided by the embodiment of the present invention may have the following beneficial effects: The present invention discloses a battery pack cooling control method, which intelligently determines the cooling requirements by monitoring the battery pack temperature in real time and comparing it with the preset optimal working range and ambient temperature. According to different cooling requirements, the combined operation of multiple cooling circuits, including a refrigerant circuit, a first liquid circuit, and a second liquid circuit, is flexibly controlled. When the battery temperature exceeds the optimal range and has a large temperature difference with the ambient temperature, the liquid circuit is started first to dissipate heat; if the effect is not good, the refrigerant circuit is started again to further cool down. When the battery temperature exceeds the optimal range but has a small temperature difference with the ambient temperature, the refrigerant circuit and the first liquid circuit are directly started for forced cooling. By precisely controlling the opening, closing, and operating parameters of each circuit, the battery pack temperature can be quickly and efficiently adjusted to ensure that the battery always operates within the optimal temperature range, thereby improving battery performance and service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 This is a flow chart of a method for controlling battery cooling during driving according to the present invention. The following will describe the technical solutions in the embodiments of the present invention in detail with reference to the accompanying drawings. The described embodiments are only a part of the embodiments of the present invention.

[0006] like Figure 1 In this embodiment, a method for controlling battery cooling during driving may specifically include: Step S101, obtain the real-time temperature of the battery pack; determine the cooling requirement of the battery pack by comparing the real-time temperature of the battery pack with the maximum limit of a preset optimal operating range, and by comparing the difference between the real-time temperature of the battery pack and the ambient temperature with a preset temperature difference threshold.

[0007] Obtaining the real-time temperature of the battery pack is the first step in a battery cooling control system. This real-time temperature can be obtained using a variety of sensors, such as thermocouples, thermistors, and infrared temperature sensors. Thermocouples utilize the principle that the electromotive force generated at the point of contact between two dissimilar metals changes with temperature. They can respond quickly to temperature changes and are suitable for high-temperature environments. Thermistors measure temperature by measuring how their resistance changes with temperature, offering high accuracy and suitable for normal temperature environments. Infrared temperature sensors measure temperature by detecting infrared radiation emitted by an object. This method requires no contact and is suitable for long-distance measurement.

[0008] For example, multiple thermistor sensors are arranged inside the battery pack to collect temperature data every 5 seconds and transmit it to the central control unit through the data acquisition module to ensure real-time monitoring of the battery pack temperature. Comparing the real-time temperature of the battery pack with the maximum limit of the preset optimal operating range is a key step in determining whether the cooling system needs to be started. The preset optimal operating range is usually provided by the battery manufacturer. For example, the optimal operating temperature range of lithium batteries is 20°C to 40°C. When the real-time temperature exceeds 40°C, the system determines that the battery pack temperature is too high and cooling measures need to be started.

[0009] For example, if the real-time temperature of the battery pack of an electric vehicle is 45°C, which exceeds the preset maximum limit of 40°C, the system will immediately sound an alarm and prepare to start the cooling system. The difference between the real-time temperature of the battery pack and the ambient temperature is compared with the preset temperature difference threshold to further confirm the urgency of the cooling need. The preset temperature difference threshold can be set according to the actual application environment, for example, 10°C. When the difference between the battery pack temperature and the ambient temperature is greater than 10°C, it indicates that the battery pack heat dissipation efficiency is low and stronger cooling measures are required.

[0010] For example, the ambient temperature is 30°C and the real-time temperature of the battery pack is 50°C, with a difference of 20°C, which exceeds the preset threshold of 10°C. The system determines that a high-intensity cooling mode needs to be activated. The cooling demand of the battery pack is determined based on a comprehensive judgment of the above comparison results. Cooling demand can be divided into multiple levels, such as low, medium, and high. Low-level cooling demand can be achieved by increasing the ventilation volume, medium cooling demand can start the fan inside the battery pack, and high cooling demand requires starting the liquid cooling system.

[0011] For example, when the battery pack temperature exceeds the maximum limit of the optimal operating range by only 2°C and the difference from the ambient temperature is less than 10°C, the system determines that low-level cooling is required and activates only the ventilation system. When the temperature exceeds 5°C and the difference is greater than 10°C, medium-level cooling is determined and the fan is activated. When the temperature exceeds 10°C and the difference is greater than 15°C, high-level cooling is determined and the liquid cooling system is activated. This hierarchical cooling strategy not only effectively controls the battery pack temperature but also adjusts the cooling intensity according to actual needs, avoiding energy waste caused by excessive cooling.

[0012] For example, in high summer temperatures, battery pack temperatures tend to rise rapidly. The system, based on real-time temperature and temperature differentials, promptly activates advanced cooling mode to maintain the optimal temperature. In spring and autumn, when ambient temperatures are lower and battery pack temperatures rise more slowly, the system only needs to activate low or medium cooling mode to conserve energy. Furthermore, the acquisition and comparison of real-time temperature data requires highly reliable data transmission and processing systems.

[0013] For example, CAN bus technology is used for data transmission, ensuring stability and real-time performance. The central control unit utilizes a high-performance microprocessor, enabling rapid processing of large amounts of temperature data and accurate judgment based on pre-set algorithms. The application of these technologies not only improves system response speed but also enhances the precision and reliability of overall cooling control. The aforementioned examples and analysis demonstrate that the process of acquiring the battery pack's real-time temperature, conducting comparative analysis, and determining cooling requirements is a complex system integrating multiple sensor technologies, data processing techniques, and control strategies. The precise implementation of each step ensures that the battery pack operates within the optimal operating temperature range, extending battery life and improving the safety and economic efficiency of electric vehicles.

[0014] Step S102, according to the determined cooling demand, controls the operation of at least one cooling circuit, wherein the cooling circuit includes a refrigerant circuit consisting of a condenser, an electric air-conditioning compressor, an electronic expansion valve and a battery cooler, a first liquid circuit consisting of a battery cooler, a battery pack water pump and a battery pack, and a second liquid circuit consisting of a battery pack water pump, a battery pack, an electronic shut-off valve and a radiator.

[0015] Based on the determined cooling requirements, the temperature of the battery pack needs to be monitored in real time first.

[0016] For example, a temperature sensor installed inside the battery pack can collect temperature data every 5 seconds and transmit the data to the control system. The control system determines whether the current battery pack needs to be cooled based on the preset temperature threshold. Assuming that the optimal operating temperature range is 20°C to 30°C, when the temperature exceeds 30°C, the system determines that the cooling circuit needs to be started. Control the operation of at least one cooling circuit, specifically including a refrigerant circuit and two liquid circuits. The refrigerant circuit consists of a condenser, an electric air-conditioning compressor, an electronic expansion valve and a battery cooler.

[0017] For example, when the battery pack temperature reaches 35°C and the ambient temperature is 25°C, a difference of 10°C, the system activates the refrigerant circuit. The electric air conditioning compressor begins operating, compressing the refrigerant into a high-temperature, high-pressure gas. This gas is then cooled in the condenser and converted to a liquid state. The electronic expansion valve then throttles and reduces the pressure. The refrigerant absorbs heat in the battery cooler, transforming from liquid to gas, removing heat from the battery pack. The first liquid circuit consists of the battery cooler, the battery pack water pump, and the battery pack. Assuming a flow rate of 10 liters / minute, the battery cooler transfers the heat absorbed by the refrigerant to the coolant in the first liquid circuit through heat exchange. The coolant circulates within the battery pack, absorbing heat from the battery pack and then returns to the battery cooler for heat exchange. This cycle continues until the battery pack temperature drops below 30°C. The second liquid circuit consists of the battery pack water pump, the battery pack, the electronic shut-off valve, and the radiator. When the battery pack temperature exceeds 30°C but the difference from the ambient temperature is no greater than 10°C, the system activates the second liquid circuit. The battery pack water pump pushes the coolant to flow in the circuit, the electronic shut-off valve opens, and the coolant dissipates heat into the air through the radiator.

[0018] For example, a radiator with a heat dissipation area of ​​2 square meters can dissipate a large amount of heat per unit time, effectively reducing the temperature of the coolant. In actual operation, the control system dynamically adjusts the operating status of each circuit based on real-time temperature data and preset cooling strategies.

[0019] For example, when the battery pack temperature rises rapidly, the system can activate both the refrigerant circuit and the secondary liquid circuit simultaneously to maximize cooling efficiency. When the temperature stabilizes, the system may maintain only the primary liquid circuit to conserve energy. The specific parameter settings for each circuit also need to be adjusted based on actual conditions.

[0020] For example, the power of the electric air conditioner compressor can be adjusted based on changes in battery pack temperature, the opening of the electronic expansion valve can be optimized based on the refrigerant flow and pressure, and the speed of the battery pack water pump can be controlled based on the coolant temperature and flow to ensure optimal cooling. The coordinated operation of multiple circuits not only effectively controls the battery pack temperature but also improves system reliability and flexibility.

[0021] For example, in high-temperature environments, the refrigerant circuit and the secondary liquid circuit can operate alternately, preventing efficiency degradation or equipment overheating caused by prolonged operation of a single circuit. The control system intelligently manages the switching and coordination between the circuits, ensuring optimal cooling performance under varying operating conditions.

[0022] For example, the control system can predict battery pack temperature trends based on historical and real-time data, proactively adjusting the circuit's operating status to avoid excessive temperature fluctuations. This multi-circuit cooling system design not only meets the battery pack's cooling needs under varying operating conditions, but also significantly extends battery life and improves the overall performance of electric vehicles.

[0023] For example, by effectively controlling the battery pack's temperature, the aging rate of the battery can be reduced, the charge and discharge efficiency can be improved, and the battery life can be extended. Ultimately, through the coordinated operation and intelligent control of various circuits, the battery cooling system can maintain a stable battery pack temperature while reducing energy consumption and improving the overall efficiency of the system.

[0024] For example, in low-temperature environments, the system can reduce the operating time of the refrigerant circuit and use the ambient temperature for free cooling, thereby saving energy.

[0025] Step S103 : Cooling the battery pack by controlling the cooling circuit to maintain the temperature of the battery pack within the optimal operating range.

[0026] The battery pack is cooled by the controlled operation of the cooling circuit to maintain the temperature of the battery pack within the optimal operating range. First, the battery pack temperature monitoring system collects the temperature data of the battery pack in real time and transmits the data to the central control unit through sensors.

[0027] For example, assuming the optimal operating range of the battery pack is 20°C to 35°C, when the sensor detects that the battery pack temperature reaches 36°C, the central control unit immediately activates the cooling circuit. In the first operating condition, when the battery pack temperature exceeds 35°C and the difference between the battery pack temperature and the ambient temperature is greater than 10°C, the system determines that it is in passive cooling mode. At this time, the central control unit controls the electronic shut-off valve to open, and the battery pack water pump starts working, pushing the coolant in the circuit. As the coolant flows through the radiator, the radiator dissipates heat into the air through its large-area heat dissipation fins.

[0028] For example, if the ambient temperature is 25°C and the battery pack temperature is 40°C, a difference of 15°C, the system activates circuits 4-5-6 and 5-6-8-7. The coolant releases heat in the radiator, gradually lowering the battery pack temperature to below 35°C. In the third operating condition, when the battery pack temperature exceeds 35°C but the difference between the battery pack temperature and the ambient temperature is no greater than 10°C, the system enters active cooling mode. At this point, the central control unit closes the electronic shutoff valve, and the refrigerant expands through the electronic expansion valve, changing from liquid to gas, absorbing a large amount of heat.

[0029] For example, if the ambient temperature is 30°C and the battery pack temperature is 36°C, a difference of 6°C, the system activates circuits 1-3-4-2 and 4-5-6. The refrigerant in the battery cooler exchanges heat with the coolant in the circuits. After absorbing the refrigerant's heat, the coolant flows through the battery pack, removing the heat and lowering the battery pack temperature to below 35°C. During implementation, the battery pack water pump flow rate and the radiator's heat dissipation efficiency must be adjusted based on actual conditions.

[0030] For example, if the battery pack temperature rises rapidly, the central control unit can increase the water pump speed, increasing the coolant flow rate and enhancing heat dissipation. The radiator's material and structural design are also crucial, such as using aluminum alloy with high thermal conductivity and increasing the number and area of ​​fins to improve heat dissipation efficiency. Furthermore, adjusting the opening of the electronic expansion valve is crucial. Precisely controlling the refrigerant flow and pressure ensures that the refrigerant fully absorbs heat during expansion.

[0031] For example, when the battery pack temperature is high, the central control unit can increase the opening of the electronic expansion valve, increasing the refrigerant flow rate and enhancing the cooling effect. Through this controlled cooling circuit, the battery pack temperature is effectively controlled and maintained within the optimal operating range. This not only ensures the performance and life of the battery pack, but also improves the safety and reliability of the entire vehicle.

[0032] For example, operating the battery pack within its optimal operating range can avoid risks such as battery performance degradation and thermal runaway caused by excessive temperatures, ensuring stable vehicle operation in high-temperature environments. Controlled operation of the cooling circuit also saves energy. In passive cooling mode, the system utilizes ambient temperature to dissipate heat, reducing energy consumption. In active cooling mode, precise control of the refrigerant flow and pressure prevents unnecessary energy waste.

[0033] For example, in low ambient temperatures, the system prioritizes passive cooling mode and activates active cooling only when necessary, thereby optimizing energy utilization. In summary, the controlled operation of the cooling circuit allows for precise control of the battery pack temperature, ensuring it operates within its optimal operating range. This improves the battery pack's performance and lifespan, ensures the safety and reliability of the vehicle, and achieves energy savings.

[0034] Step S104, controlling the operation of at least one cooling circuit based on the determined cooling requirements, includes: if the real-time temperature of the battery pack exceeds the maximum limit of the optimal operating range, and the difference between the real-time temperature of the battery pack and the ambient temperature is greater than the preset temperature difference threshold, operating the first liquid circuit and the second liquid circuit. Furthermore, operating the first liquid circuit and the second liquid circuit includes: opening the electronic shut-off valve; driving the liquid in the first liquid circuit and the second liquid circuit to flow via the battery pack water pump; and dissipating the heat of the liquid in the second liquid circuit to the air via the radiator. Furthermore, if the real-time temperature of the battery pack still cannot be effectively reduced, operating the refrigerant circuit while operating the first liquid circuit and the second liquid circuit.

[0035] When the real-time temperature of the battery pack exceeds the maximum limit of the optimal operating range and the difference between the real-time temperature of the battery pack and the ambient temperature is greater than a preset temperature difference threshold, the system starts the operation of the first liquid circuit and the second liquid circuit.

[0036] For example, assume the maximum limit of the optimal operating range is 35°C, the preset temperature difference threshold is 10°C, the ambient temperature is 25°C, and the real-time temperature of the battery pack is 40°C. Because 40°C exceeds the maximum limit of 35°C, and the difference between 40°C and 25°C is 15°C, which is greater than the 10°C threshold, the system determines that cooling should be initiated. First, the system opens the electronic shut-off valve to ensure that the liquid can flow freely in the circuit. The electronic shut-off valve acts like a switch: when it is open, the liquid can pass smoothly; otherwise, it is blocked. This step is crucial because only when the shut-off valve is open can the liquid enter the cooling circuit and begin the cooling process. Next, the battery pack water pump drives the liquid flow in the first and second liquid circuits. The battery pack water pump is similar to a heart, providing power to the liquid and allowing it to circulate in the circuit.

[0037] For example, a water pump with a power of 500W and a flow rate of 10L / min means that 10 liters of coolant flow through the loop every minute, removing heat from the battery pack. In the second liquid loop, the liquid flows through a radiator, which dissipates heat from the liquid into the air. The radiator typically consists of aluminum fins and pipes, with the liquid flowing through the pipes and heat transferred to the air through the fins.

[0038] For example, a radiator with a heat dissipation area of ​​1 square meter and an air velocity of 5 m / s can dissipate a large amount of heat in a short period of time, lowering the liquid temperature. If these cooling measures still fail to effectively lower the battery pack temperature, the system will further activate the refrigerant circuit. The refrigerant circuit works by absorbing heat through the refrigerant's phase change to achieve cooling.

[0039] For example, after refrigerant R134a expands in the electronic expansion valve, it changes from liquid to gas, absorbing a large amount of heat. This process is similar to evaporation, and the refrigerant's temperature drops significantly after absorbing heat. The refrigerant in the refrigerant circuit passes through the battery cooler, exchanging heat with the liquid in the first and second liquid circuits. The battery cooler acts like a heat exchanger, and the refrigerant flows through the cooler, exchanging heat with the liquid, further lowering the liquid's temperature.

[0040] For example, the battery cooler boasts a 90% heat exchange efficiency, quickly transferring heat absorbed by the refrigerant to the liquid, significantly reducing its temperature. By integrating these three circuits, the system efficiently reduces the battery pack temperature, ensuring it remains within the optimal operating range. This multi-stage cooling strategy not only improves cooling efficiency but also enhances system reliability and stability.

[0041] For example, when driving in high-temperature environments, the battery pack temperature rises rapidly. The system activates the first and second liquid circuits to initially reduce the temperature. If the temperature remains high, the refrigerant circuit activates to further reduce the temperature, ensuring that the battery pack always operates within the optimal operating range. This cooling strategy also effectively extends the battery life and prevents battery performance degradation caused by high temperatures.

[0042] For example, prolonged operation of batteries in high-temperature environments can lead to problems such as electrolyte evaporation and electrode material aging, shortening battery life. Timely cooling can effectively avoid these problems and extend the battery's service life. In summary, by precisely controlling the operation of the cooling circuit, the system can flexibly adjust the cooling strategy based on the battery pack's real-time temperature and ambient temperature, ensuring that the battery pack always operates within its optimal operating range, thereby improving vehicle safety and reliability.

[0043] Step S105, operating the refrigerant circuit while operating the first liquid circuit and the second liquid circuit, includes: circulating the refrigerant in the refrigerant circuit through the electric air-conditioning compressor; regulating the flow of the refrigerant through the electronic expansion valve; and exchanging heat between the refrigerant and the liquid in the first liquid circuit through the battery cooler.

[0044] First, the refrigerant is circulated through the refrigerant circuit by the electric air conditioning compressor. As the power source for the refrigerant cycle, the electric air conditioning compressor operates similarly to the compressor in a traditional air conditioning system.

[0045] For example, in a specific application scenario, the power of the electric air-conditioning compressor is set at 5 kilowatts, which can compress refrigerants such as R134a from a low-pressure, low-temperature state to a high-pressure, high-temperature state. During this process, the temperature of the refrigerant can rise from -10°C to 60°C, and the pressure can increase from 0.2 MPa to 1.5 MPa. This high-pressure, high-temperature refrigerant then enters the condenser, which dissipates the heat of the refrigerant to the environment through air convection or water cooling, causing the refrigerant to change from gas to liquid and the temperature to drop to around 30°C. Secondly, the refrigerant flow rate is regulated by an electronic expansion valve. The electronic expansion valve acts like a throttling device, which can accurately control the flow and pressure of the refrigerant, thereby adjusting the evaporation temperature of the refrigerant.

[0046] For example, during system operation, the electronic expansion valve dynamically adjusts its opening based on feedback from the battery pack's temperature sensor. Assuming the battery pack's current temperature is 45°C and the ambient temperature is 35°C, the electronic expansion valve adjusts its opening to 50%, controlling the refrigerant flow rate to 0.8 liters per minute. This ensures that the refrigerant fully evaporates in the battery cooler, absorbing more heat. Furthermore, the battery cooler exchanges heat with the liquid in the first liquid circuit. Battery coolers typically use a plate heat exchanger structure, which offers high heat exchange efficiency.

[0047] For example, under certain operating conditions, the battery cooler has a heat exchange area of ​​2 square meters. The refrigerant in the battery cooler changes from liquid to gas, absorbing a significant amount of heat. Assume that the liquid in the first liquid circuit is a water-based coolant with an initial temperature of 40°C. After passing through the battery cooler, the temperature drops to 30°C. During this process, the refrigerant temperature drops from 30°C to -5°C, completing the heat transfer. In specific implementation, the startup and operation of the electric air conditioner compressor must be linked to the real-time temperature monitoring system of the battery pack. When the battery pack temperature exceeds a set threshold, such as 35°C, the electric air conditioner compressor automatically starts and begins circulating the refrigerant. Simultaneously, the electronic expansion valve dynamically adjusts its opening according to a preset control algorithm to ensure that the refrigerant flow rate matches the battery pack's heat dissipation requirements. The design of the battery cooler must consider heat exchange efficiency and flow resistance. A multi-channel structure is typically used to increase the heat exchange area and improve heat exchange efficiency. Furthermore, the system's operation must also consider the impact of ambient temperature.

[0048] For example, in high-temperature environments, the condenser's heat dissipation efficiency may decrease. In this case, increasing the condenser fan speed or using water cooling to assist in heat dissipation can ensure effective condensation of the refrigerant. The adjustment accuracy of the electronic expansion valve also directly impacts the system's cooling performance. Typically driven by a stepper motor, it can achieve micron-level opening adjustment, ensuring precise control of the refrigerant flow rate. Through these measures, the coordinated operation of the refrigerant circuit, the first liquid circuit, and the second liquid circuit effectively reduces the battery pack temperature, ensuring that the battery operates within its optimal operating range. The continuous operation of the electric air conditioning compressor ensures efficient refrigerant circulation, while the precise adjustment of the electronic expansion valve ensures that the refrigerant flow rate matches the heat dissipation requirements. The efficient heat exchange of the battery cooler facilitates heat exchange between the refrigerant and the coolant, ultimately cooling the battery pack. This composite cooling system design not only improves the heat dissipation efficiency of the battery pack, but also extends the battery life, enhancing the overall performance and safety of the electric vehicle. By synergizing multiple circuits, the system can flexibly adjust its cooling strategy under different operating conditions, ensuring stable battery pack operation in various environmental conditions.

[0049] Step S106, controlling the operation of at least one cooling circuit according to the determined cooling demand, includes: if the real-time temperature of the battery pack exceeds the maximum limit of the optimal operating range, and the difference between the real-time temperature of the battery pack and the ambient temperature is not greater than the preset temperature difference threshold, operating the refrigerant circuit and the first liquid circuit.

[0050] The electronic expansion valve adjusts the flow of refrigerant according to the instructions of the central control unit. The refrigerant changes from high-pressure liquid to low-pressure gas at the expansion valve, and this process absorbs a large amount of heat.

[0051] For example, the refrigerant R134a changes from a high-pressure liquid (assuming the pressure is 10MPa and the temperature is 50°C) to a low-pressure gas (assuming the pressure is 0.5MPa and the temperature is -10°C) at the expansion valve. The heat absorbed during this phase change process can effectively reduce the temperature of the battery pack. The operation of the first liquid circuit is achieved through the battery cooler. The battery cooler is equipped with a heat exchange pipeline inside. The refrigerant flows in the pipeline and exchanges heat with the coolant circulating outside the pipeline. Assuming that the initial temperature of the coolant is 30°C, after passing through the battery cooler, the temperature drops to 25°C. This process removes some of the heat from the battery pack. During specific implementation, the central control unit issues control instructions based on real-time temperature data and preset parameters.

[0052] For example, when the battery pack temperature is 36°C and the ambient temperature is 25°C, with a difference of 11°C, the system determines that the condition of the difference being no more than 10°C is not met, and the refrigerant circuit and the first liquid circuit are not started. However, when the battery pack temperature is 34°C and the ambient temperature is 30°C, with a difference of 4°C, the condition is met, and the system starts the refrigerant circuit and the first liquid circuit for active cooling. In this way, the temperature of the battery pack can be effectively controlled within the optimal operating range. Compared with passive cooling, active cooling can reduce the battery pack temperature more quickly and improve cooling efficiency.

[0053] For example, when driving in high-temperature environments, the battery pack temperature rises rapidly. Active cooling can quickly reduce the temperature to a safe range, ensuring battery performance and driving safety. Furthermore, the opening and closing of the electronic shut-off valve are controlled based on cooling needs. In active cooling mode, the valve closes, ensuring efficient operation of the refrigerant circuit; in passive cooling mode, the valve opens, allowing coolant to dissipate heat through the radiator. This multi-circuit cooling system design not only improves cooling efficiency but also increases system flexibility and reliability.

[0054] For example, under complex operating conditions, the system can dynamically adjust the cooling strategy based on real-time and ambient temperature changes to ensure the battery pack always operates within its optimal operating range. The above examples and analysis demonstrate that a strategy that controls the operation of at least one cooling circuit based on determined cooling requirements can effectively address battery pack temperature control requirements under varying operating conditions, ensuring battery pack safety and performance, and improving vehicle reliability and user experience.

[0055] Step S107, operating the refrigerant circuit and the first liquid circuit, includes: closing the electronic shut-off valve; circulating the refrigerant in the refrigerant circuit through the electric air-conditioning compressor; regulating the flow rate of the refrigerant through the electronic expansion valve; and exchanging heat between the refrigerant and the liquid in the first liquid circuit through the battery cooler.

[0056] The electronic shut-off valve is closed to ensure that the refrigerant circuit and the first liquid circuit operate independently.

[0057] For example, if the battery pack temperature exceeds the maximum limit of the optimal operating range and is no more than 10°C different from the ambient temperature, the system automatically closes the electronic shutoff valve to prevent direct mixing of refrigerant with the first liquid circuit, ensuring cooling efficiency. Closing the electronic shutoff valve is achieved through electromagnetic control. Upon receiving a control signal, the valve rapidly responds to the control signal, severing the connection between the two circuits and ensuring that the refrigerant circulates in an independent circuit, avoiding energy loss. The refrigerant circulates in the refrigerant circuit via the electric air conditioning compressor.

[0058] For example, after the electric air conditioner compressor starts, it compresses the low-pressure, low-temperature refrigerant gas into a high-pressure, high-temperature gas, which releases heat in the condenser and condenses into a liquid. The power of the electric air conditioner compressor can be adjusted according to the temperature changes of the battery pack to ensure stable flow and pressure of the refrigerant in the circuit. Assuming the electric air conditioner compressor speed is 3000 rpm and the compression ratio is 10:1, the refrigerant temperature at the compressor outlet can reach 70°C and the pressure is 2.5 MPa, ensuring efficient heat transfer. The refrigerant flow is regulated by the electronic expansion valve.

[0059] For example, the electronic expansion valve precisely controls the refrigerant flow rate based on feedback from the battery pack temperature sensor, allowing it to expand and cool before entering the battery cooler. Assuming the current battery pack temperature is 45°C and the ambient temperature is 35°C, the system sets the expansion valve opening to 50%. This reduces the refrigerant temperature to -10°C and the pressure to 0.5 MPa at the expansion valve outlet, ensuring that the refrigerant fully absorbs heat in the battery cooler. The battery cooler allows the refrigerant to exchange heat with the liquid in the first liquid circuit.

[0060] For example, the battery cooler incorporates a microchannel heat exchanger. Refrigerant flows through the microchannels, exchanging heat with the coolant in the first liquid circuit. Assuming the coolant's initial temperature is 30°C, it rises to 35°C after passing through the battery cooler, while the refrigerant's temperature rises from -10°C to 20°C. This effectively transfers heat from the battery pack to the refrigerant and then to the coolant. In specific implementation, the battery cooler's heat exchange area is designed to be 1 square meter to ensure sufficient heat exchange efficiency. The coolant flow rate is controlled at 0.5 cubic meters per hour to ensure sufficient heat exchange time. The electronic expansion valve has a response time of 0.1 seconds, ensuring rapid adjustment of the refrigerant flow rate to accommodate real-time changes in the battery pack temperature. Why this? Closing the electronic shut-off valve prevents direct mixing of refrigerant and coolant, ensuring efficient operation of each circuit. The use of an electric air conditioning compressor provides continuous high-pressure, high-temperature refrigerant, ensuring effective heat release in the condenser. Precise adjustment of the electronic expansion valve ensures that the refrigerant fully absorbs heat in the battery cooler, improving cooling efficiency. The battery cooler's microchannel design increases the heat exchange area and improves heat exchange efficiency. What useful technical benefits does this bring? First, it ensures that the battery pack cools quickly in high-temperature environments, extending battery life. Second, by precisely controlling the refrigerant flow and pressure, the system's energy efficiency ratio is improved and energy consumption is reduced. Finally, each circuit operates independently, avoiding mutual interference and improving system stability and reliability. In practical applications, this technical solution can be widely used in electric vehicle battery cooling systems, ensuring stable battery operation in high-temperature environments and enhancing vehicle safety and endurance.

[0061] For example, in high summer temperatures, the battery pack temperature rises rapidly. The system activates active cooling mode, where the electric air conditioning compressor, electronic expansion valve, and battery cooler work together to quickly reduce the battery pack temperature and ensure normal vehicle operation. Furthermore, this technical solution can also be applied to the battery cooling system of energy storage power stations, ensuring the safe operation of large-scale battery packs in high-temperature environments.

[0062] For example, battery packs in energy storage power stations are prone to overheating in high-temperature environments. The system activates active cooling mode, precisely controlling the refrigerant flow and pressure to rapidly reduce the battery pack temperature and prevent thermal runaway accidents. Numerous examples and analyses demonstrate that this technical solution, through the coordinated work of various components, achieves efficient and precise battery cooling, demonstrating broad application prospects and practical value.

[0063] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A battery cooling control method during driving, characterized in that: include: Obtaining the real-time temperature of the battery pack; determining the cooling requirement of the battery pack by comparing the real-time temperature of the battery pack with a maximum limit of a preset optimal operating range, and by comparing the difference between the real-time temperature of the battery pack and the ambient temperature with a preset temperature difference threshold; controlling the operation of at least one cooling circuit according to the determined cooling requirement, the cooling circuit comprising a refrigerant circuit consisting of a condenser, an electric air-conditioning compressor, an electronic expansion valve, and a battery cooler, a first liquid circuit consisting of a battery cooler, a battery pack water pump, and a battery pack, and a second liquid circuit consisting of a battery pack water pump, a battery pack, an electronic shut-off valve, and a radiator; cooling the battery pack through the controlled operation of the cooling circuit to maintain the temperature of the battery pack within the optimal operating range.

2. The method according to claim 1, wherein The controlling the operation of at least one cooling circuit according to the determined cooling demand includes: if the real-time temperature of the battery pack exceeds the maximum limit of the optimal operating range, and the difference between the real-time temperature of the battery pack and the ambient temperature is greater than the preset temperature difference threshold, operating the first liquid circuit and the second liquid circuit.

3. The method according to claim 2, wherein The operation of the first liquid circuit and the second liquid circuit includes: opening the electronic shut-off valve; driving the liquid in the first liquid circuit and the second liquid circuit to flow through the battery pack water pump; and dissipating the heat of the liquid in the second liquid circuit into the air through the radiator.

4. The method according to claim 2, wherein If the real-time temperature of the battery pack still cannot be effectively reduced, the refrigerant circuit is operated while the first liquid circuit and the second liquid circuit are operated.

5. The method according to claim 4, wherein The operating of the refrigerant circuit while operating the first liquid circuit and the second liquid circuit includes: circulating the refrigerant in the refrigerant circuit through the electric air-conditioning compressor; regulating the flow rate of the refrigerant through the electronic expansion valve; and exchanging heat between the refrigerant and the liquid in the first liquid circuit through the battery cooler.

6. The method according to claim 4, wherein If the difference between the real-time temperature of the battery pack and the ambient temperature is not greater than the preset temperature difference threshold when the refrigerant circuit, the first liquid circuit, and the second liquid circuit are operating simultaneously, the electronic shut-off valve is closed and only the refrigerant circuit and the first liquid circuit are operating.

7. The method according to claim 1, wherein The controlling of the operation of at least one cooling circuit according to the determined cooling demand includes: if the real-time temperature of the battery pack exceeds the maximum limit of the optimal operating range and the difference between the real-time temperature of the battery pack and the ambient temperature is not greater than the preset temperature difference threshold, operating the refrigerant circuit and the first liquid circuit.

8. The method according to claim 7, wherein The operation of the refrigerant circuit and the first liquid circuit includes: closing the electronic shut-off valve; circulating the refrigerant in the refrigerant circuit through the electric air-conditioning compressor; regulating the flow rate of the refrigerant through the electronic expansion valve; and exchanging heat between the refrigerant and the liquid in the first liquid circuit through the battery cooler.

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