A battery cooling control method during driving

Abstract

The application provides a battery cooling control method during driving, and belongs to the technical field of battery control. The method comprises the following steps: acquiring the real-time temperature of a battery pack; comparing the real-time temperature of the battery pack with the maximum limit value of a preset optimal working range, and comparing the difference between the real-time temperature of the battery pack and the ambient temperature with a preset temperature difference threshold, to determine the cooling demand of the battery pack; controlling at least one cooling circuit to operate according to the determined cooling demand; and cooling the battery pack through the controlled cooling circuit, so that the temperature of the battery pack is maintained within the optimal working range. The application realizes rapid and efficient adjustment of the temperature of the battery pack by precisely controlling the opening, closing and operating parameters of each circuit, ensures that the battery always works within the optimal temperature range, and improves the performance and service life of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery control technology, and in particular to a method for controlling battery cooling during vehicle operation. Background Technology

[0002] Battery pack temperature control is a critical factor in the performance and lifespan of electric vehicles, but it faces complex and variable operating environments and load conditions. Precisely adjusting battery temperature under different operating conditions to keep it within its optimal operating range is a significant challenge. Traditional single cooling methods struggle to adapt to diverse heat dissipation needs, easily leading to insufficient or excessive cooling, which negatively impacts battery performance. Furthermore, frequent start-stop cycles of the cooling system increase energy consumption and component wear. In addition, uneven temperature distribution within the battery pack makes it difficult to effectively address localized overheating issues. In high-temperature environments, the cooling system's heat dissipation capacity is limited, making it difficult to quickly reduce battery temperature. Conversely, in low-temperature environments, excessive cooling reduces battery activity. How to intelligently determine cooling needs based on real-time operating conditions and flexibly allocate various cooling resources to achieve precise temperature control is a pressing technical challenge. This not only relates to battery lifespan 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 while balancing cooling efficiency and energy consumption is of great significance for improving the overall performance of electric vehicles. Summary of the Invention

[0003] This invention provides a battery cooling control method during vehicle operation, mainly comprising: The system acquires the real-time temperature of the battery pack; compares the real-time temperature of the battery pack with the maximum limit of the preset optimal operating range, and compares the difference between the real-time temperature of the battery pack and the ambient temperature with a preset temperature difference threshold to determine the cooling requirements of the battery pack; based on the determined cooling requirements, it controls the operation of at least one cooling circuit, which 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 the battery pack; and a second liquid circuit consisting of a battery pack water pump, the battery pack, an electronic shut-off valve, and a radiator; and cools the battery pack through the controlled operation of the cooling circuit to maintain the temperature of the battery pack within the optimal operating range.

[0004] Furthermore, controlling the operation of at least one cooling circuit according to 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, then the first liquid circuit and the second liquid circuit are operated.

[0005] Furthermore, operating the first liquid circuit and the second liquid circuit includes: opening the electronic shut-off valve; driving the liquid flow in the first liquid circuit and the second liquid circuit through the battery pack water pump; and dissipating the heat of the liquid in the second liquid circuit into the air through the radiator.

[0006] Furthermore, if the real-time temperature of the battery pack still cannot be effectively reduced, the refrigerant circuit is operated simultaneously with the first liquid circuit and the second liquid circuit.

[0007] Furthermore, operating the refrigerant circuit while operating the first liquid circuit and the second liquid circuit includes: circulating the refrigerant in the refrigerant circuit via the electric air conditioning compressor; regulating the flow rate of the refrigerant via the electronic expansion valve; and exchanging heat between the refrigerant and the liquid in the first liquid circuit via the battery cooler.

[0008] Furthermore, 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 during the simultaneous operation of the refrigerant circuit, the first liquid circuit, and the second liquid circuit, then the electronic shut-off valve is closed, and only the refrigerant circuit and the first liquid circuit are operated.

[0009] Furthermore, controlling the operation of at least one cooling circuit according to 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 not greater than the preset temperature difference threshold, then the refrigerant circuit and the first liquid circuit are operated.

[0010] Furthermore, operating the refrigerant circuit and the first liquid circuit includes: closing the electronic shut-off valve; circulating the refrigerant in the refrigerant circuit via the electric air conditioning compressor; adjusting the flow rate of the refrigerant via the electronic expansion valve; and exchanging heat between the refrigerant and the liquid in the first liquid circuit via the battery cooler.

[0011] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects: This invention discloses a battery pack cooling control method. By monitoring the battery pack temperature in real time and comparing it with a preset optimal operating range and ambient temperature, the method intelligently determines cooling requirements. Based on different cooling needs, it flexibly controls the combined operation of multiple cooling circuits, including a refrigerant circuit, a first liquid circuit, and a second liquid circuit. When the battery temperature exceeds the optimal range and the temperature difference with the environment is large, the liquid circuit is activated first for heat dissipation; if this is ineffective, the refrigerant circuit is then activated for further cooling. When the battery temperature exceeds the optimal range but the temperature difference with the environment is small, the refrigerant circuit and the first liquid circuit are directly activated for forced cooling. By precisely controlling the opening, closing, and operating parameters of each circuit, rapid and efficient adjustment of the battery pack temperature is achieved, ensuring that the battery always operates within the optimal temperature range, thereby improving battery performance and lifespan. Attached Figure Description

[0012] Figure 1 This is a flowchart of a battery cooling control method during vehicle operation according to the present invention. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.

[0014] like Figure 1 This embodiment of a battery cooling control method during vehicle operation may specifically include: Step S101: Obtain the real-time temperature of the battery pack; determine the cooling requirements of the battery pack by comparing the real-time temperature of the battery pack with the maximum limit of the 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.

[0015] Obtaining the real-time temperature of the battery pack is the first step in a battery cooling control system. Real-time temperature acquisition can be achieved using various sensors, such as thermocouple sensors, thermistor sensors, and infrared temperature sensors. Thermocouple sensors utilize the principle that the electromotive force generated at the contact point of two different metals changes with temperature, enabling rapid response to temperature changes and making them suitable for high-temperature environments. Thermistor sensors measure temperature based on the characteristic that resistance changes with temperature, offering high accuracy and suitability for room-temperature environments. Infrared temperature sensors measure temperature by detecting the infrared radiation emitted by objects, requiring no contact and making them suitable for long-distance measurements.

[0016] For example, multiple thermistor sensors are placed inside the battery pack to collect temperature data every 5 seconds, which is then transmitted to the central control unit via a 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 a preset optimal operating range is a crucial step in determining whether the cooling system needs to be activated. The preset optimal operating range is typically provided by the battery manufacturer; for example, the optimal operating temperature range for 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 activated.

[0017] For example, if the real-time temperature of an electric vehicle's battery pack reaches 45°C, exceeding the preset maximum limit of 40°C, the system will immediately issue an alarm and prepare to activate the cooling system. Comparing the difference between the real-time battery pack temperature and the ambient temperature with a preset temperature difference threshold further confirms the urgency of the cooling requirement. 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's heat dissipation efficiency is low, requiring stronger cooling measures.

[0018] For example, if the ambient temperature is 30°C and the real-time battery pack temperature is 50°C, the difference is 20°C, exceeding the preset 10°C threshold. The system then determines that a high-intensity cooling mode needs to be activated. Determining the battery pack's cooling requirements is based on a comprehensive judgment of the above comparison results. Cooling requirements can be categorized into several levels, such as low, medium, and high. Low-level cooling can be achieved by increasing ventilation, medium-level cooling can be achieved by activating the internal fans of the battery pack, and high-level cooling requires activating the liquid cooling system.

[0019] For example, when the battery pack temperature exceeds the maximum limit of its optimal operating range by only 2°C and the temperature difference with the ambient temperature is less than 10°C, the system determines it as a low-level cooling requirement and only activates the ventilation system. When the temperature exceeds 5°C and the temperature difference is greater than 10°C, it is determined as a medium-level cooling requirement and the fan is activated. When the temperature exceeds 10°C and the temperature difference is greater than 15°C, it is determined as a high-level cooling requirement and the liquid cooling system is activated. This tiered 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 over-cooling.

[0020] For example, in high-temperature environments during summer, the battery pack temperature can rise rapidly. The system, based on real-time temperature and the temperature difference, promptly activates an advanced cooling mode to ensure the battery pack temperature remains within the optimal range. In spring and autumn, when ambient temperatures are lower, the battery pack temperature rises slowly, and the system only needs to activate a low- or medium-level cooling mode, saving energy. Furthermore, the acquisition and comparison of real-time temperature data requires a highly reliable data transmission and processing system.

[0021] For example, CAN bus technology is used for data transmission to ensure stability and real-time performance; the central control unit employs a high-performance microprocessor capable of rapidly processing large amounts of temperature data and making accurate judgments based on preset algorithms. The application of these technologies not only improves the system's response speed but also enhances the accuracy and reliability of overall cooling control. Through the above examples and analyses, it can be seen that acquiring the real-time temperature of the battery pack, comparing and judging it, and determining cooling requirements constitutes a complex system integrating multiple sensor technologies, data processing technologies, and control strategies. The precise implementation of each step provides a strong guarantee for ensuring the battery pack operates within its optimal operating temperature range, extending battery life, and improving the safety and economy of electric vehicles.

[0022] Step S102: Based on the determined cooling requirements, control the operation of at least one cooling circuit. 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.

[0023] Based on the determined cooling requirements, the temperature of the battery pack needs to be monitored in real time.

[0024] 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 battery pack needs cooling based on a preset temperature threshold. Assuming the optimal operating temperature range is 20°C to 30°C, the system determines that the cooling circuit needs to be activated when the temperature exceeds 30°C. At least one cooling circuit is controlled, 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.

[0025] 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 starts working, compressing the refrigerant into a high-temperature, high-pressure gas. After being cooled by the condenser, it becomes liquid, and then its pressure is reduced by the electronic expansion valve. The refrigerant absorbs heat in the battery cooler, changing from liquid to gas, carrying away the heat from the battery pack. The first liquid circuit consists of the battery cooler, the battery pack water pump, and the battery pack. Assuming the battery pack water pump has 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 inside 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 between it and the ambient temperature is no more than 10°C, the system activates the second liquid circuit. The battery pack water pump drives the coolant to flow in the circuit, the electronic shut-off valve opens, and the coolant dissipates heat into the air through the radiator.

[0026] 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 monitored temperature data and preset cooling strategies.

[0027] For example, when the battery pack temperature rises rapidly, the system can simultaneously activate the refrigerant circuit and the second liquid circuit for maximum cooling efficiency. When the temperature stabilizes, the system may only maintain the operation of the first liquid circuit to conserve energy. The specific parameter settings for each circuit also need to be adjusted according to the actual situation.

[0028] For example, the power of the electric air conditioning compressor can be adjusted according to changes in the 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 performance. Through the coordinated operation of multiple loops, not only can the battery pack temperature be effectively controlled, but the system's reliability and flexibility can also be improved.

[0029] For example, in high-temperature environments, the refrigerant circuit and the second liquid circuit can operate alternately, avoiding efficiency degradation or equipment overheating caused by prolonged operation of a single circuit. The switching and coordination between circuits are intelligently controlled by the control system to ensure optimal cooling performance under different operating conditions.

[0030] For example, the control system can predict the temperature change trend of the battery pack based on historical and real-time data, and adjust the operating status of the circuits in advance to avoid excessive temperature fluctuations. This multi-loop cooling system design not only meets the cooling requirements of the battery pack under different operating conditions, but also significantly extends the battery's lifespan and improves the overall performance of the electric vehicle.

[0031] For example, by effectively controlling the temperature of the battery pack, the rate of battery aging can be reduced, the charging and discharging efficiency of the battery can be improved, thereby extending the battery's lifespan. Ultimately, through the coordinated work and intelligent control of each circuit, the battery cooling system can reduce energy consumption and improve the overall efficiency of the system while ensuring stable battery pack temperature.

[0032] For example, in low-temperature environments, the system can reduce the operating time of the refrigerant circuit and utilize ambient temperature for natural cooling, thereby saving energy.

[0033] Step S103: The battery pack is cooled by the controlled cooling circuit so that the temperature of the battery pack is maintained within the optimal operating range.

[0034] The battery pack is cooled by the controlled cooling circuit to maintain its temperature within the optimal operating range. First, the battery pack temperature monitoring system collects temperature data in real time and transmits the data to the central control unit via sensors.

[0035] 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 temperature difference between the battery pack and the ambient temperature is greater than 10°C, the system determines it to be 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, driving the coolant flow in the circuit. As the coolant flows through the radiator, the radiator dissipates heat into the air through its large-area heat dissipation fins.

[0036] For example, if the ambient temperature is 25°C and the battery pack temperature is 40°C, with 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 determines it to be in active cooling mode. At this time, the central control unit closes the electronic shut-off valve, and the refrigerant expands through the electronic expansion valve, changing from a liquid to a gaseous state, absorbing a large amount of heat.

[0037] For example, if the ambient temperature is 30℃ and the battery pack temperature is 36℃, the difference is 6℃, and the system activates two circuits: sequence 1-3-4-2 and sequence 4-5-6. The refrigerant exchanges heat with the coolant in the circuit within the battery cooler. The coolant absorbs heat from the refrigerant and flows through the battery pack, carrying away heat and lowering the battery pack temperature to below 35℃. In practice, the flow rate of the battery pack water pump and the heat dissipation efficiency of the radiator need to be adjusted according to the actual situation.

[0038] For example, if the battery pack temperature rises rapidly, the central control unit can increase the water pump speed, increase the coolant flow rate, and enhance heat dissipation. Meanwhile, the material and structural design of the radiator are also crucial; for instance, using high thermal conductivity aluminum alloys and increasing the number and area of ​​heat dissipation fins can improve heat dissipation efficiency. Furthermore, the opening adjustment of the electronic expansion valve is also a key aspect. By precisely controlling the refrigerant flow and pressure, it ensures that the refrigerant fully absorbs heat during expansion.

[0039] 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 and thus enhancing the cooling effect. Through this controlled cooling circuit, the battery pack temperature is effectively controlled and maintained within its optimal operating range. This not only ensures the performance and lifespan of the battery pack but also improves the safety and reliability of the entire vehicle.

[0040] For example, operating the battery pack within its optimal operating range avoids risks such as battery performance degradation and thermal runaway caused by excessively high temperatures, ensuring stable vehicle operation in high-temperature environments. Controlled operation of the cooling circuit also results in energy savings. In passive cooling mode, the system utilizes ambient temperature for heat dissipation, reducing energy consumption. In active cooling mode, precise control of refrigerant flow and pressure prevents unnecessary energy waste.

[0041] For example, in low ambient temperatures, the system prioritizes passive cooling, only activating active cooling when necessary, thus optimizing energy utilization. In summary, through a controlled cooling circuit, the battery pack's temperature is precisely controlled, ensuring it operates within its optimal range, improving battery pack performance and lifespan, guaranteeing vehicle safety and reliability, and achieving energy savings.

[0042] Step S104, controlling the operation of at least one cooling circuit according to 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, then the first liquid circuit and the second liquid circuit are operated. Further, operating the first liquid circuit and the second liquid circuit includes: opening the electronic shut-off valve; driving the liquid flow in the first liquid circuit and the second liquid circuit through the battery pack water pump; and dissipating the heat from the liquid in the second liquid circuit into the air through the radiator. Further, if the real-time temperature of the battery pack still cannot be effectively reduced, then the refrigerant circuit is operated simultaneously with the operation of the first liquid circuit and the second liquid circuit.

[0043] 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 the preset temperature difference threshold, the system will start the operation of the first liquid circuit and the second liquid circuit.

[0044] For example, assuming the maximum limit of the optimal operating range is 35℃, the preset temperature difference threshold is 10℃, the ambient temperature is 25℃, and the real-time temperature of the battery pack is 40℃. Since 40℃ exceeds the maximum limit of 35℃, and the difference between 40℃ and 25℃ is 15℃, which is greater than the 10℃ threshold, the system determines that cooling needs to 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 through smoothly, and vice versa. 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 like the heart, providing power to the liquid and circulating it in the circuit.

[0045] 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 circuit every minute, carrying away heat from the battery pack. In the second liquid circuit, the liquid flows through a radiator, whose function is to dissipate the heat from the liquid into the air. Radiators typically consist of aluminum fins and pipes; the liquid flows through the pipes, and heat is transferred to the air through the fins.

[0046] For example, a radiator with a heat dissipation area of ​​1 square meter and an airflow velocity of 5 m / s can dissipate a large amount of heat in a short time, reducing the temperature of the liquid. If the above cooling measures are still insufficient to effectively reduce the battery pack temperature, the system will further activate the refrigerant circuit. The refrigerant circuit works by absorbing heat through the phase change of the refrigerant to achieve cooling.

[0047] For example, after refrigerant R134a expands in the electronic expansion valve, it changes from a liquid to a gas, absorbing a large amount of heat. This process is similar to evaporation endothermics, and the refrigerant's temperature drops significantly after absorbing heat. The refrigerant in the refrigerant circuit passes through a battery cooler, exchanging heat with the liquids in the first and second liquid circuits. The battery cooler functions like a heat exchanger; the refrigerant flows within it, exchanging heat with the liquids and further reducing their temperature.

[0048] For example, the battery cooler has a heat exchange efficiency of 90%, enabling it to transfer the heat absorbed by the refrigerant to the liquid in a short time, significantly reducing the liquid's temperature. Through the coordination of three loops, the system can efficiently reduce the battery pack's temperature, ensuring it remains within its optimal operating range. This multi-stage cooling strategy not only improves cooling efficiency but also enhances the system's reliability and stability.

[0049] For example, when driving in high-temperature environments, the battery pack temperature rises rapidly. The system initially reduces the temperature by activating the first and second liquid circuits. If the temperature remains high, the refrigerant circuit activates to further cool the battery pack, ensuring it always operates within its optimal operating range. Furthermore, this cooling strategy effectively extends battery life and prevents performance degradation caused by high temperatures.

[0050] 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 battery life. In summary, by precisely controlling the operation of the cooling circuit, the system can flexibly adjust the cooling strategy based on changes in the real-time temperature of the battery pack and the ambient temperature, ensuring that the battery pack always operates within its optimal operating range, thereby improving vehicle safety and reliability.

[0051] 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; adjusting 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.

[0052] First, the refrigerant circulates in the refrigerant circuit through an electric air conditioning compressor. The electric air conditioning compressor, as the power source for the refrigerant circulation, operates on a principle similar to that of a compressor in a traditional air conditioning system.

[0053] For example, in a specific application scenario, the electric air conditioner compressor is set to a power of 5 kW, capable of compressing refrigerant such as R134a from a low-pressure, low-temperature state to a high-pressure, high-temperature state. During this process, the refrigerant temperature can rise from -10°C to 60°C, and the pressure from 0.2 MPa to 1.5 MPa. This high-pressure, high-temperature refrigerant then enters the condenser, where the condenser dissipates the heat of the refrigerant into the environment through air convection or water cooling, causing the refrigerant to change from a gaseous state to a liquid state, and its temperature to drop to around 30°C. Next, the refrigerant flow rate is regulated by an electronic expansion valve. The electronic expansion valve functions similarly to a throttling device, precisely controlling the refrigerant flow rate and pressure, thereby regulating the refrigerant's evaporation temperature.

[0054] For example, during system operation, the electronic expansion valve dynamically adjusts its opening based on feedback signals 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 will adjust its opening to 50%, controlling the refrigerant flow rate at 0.8 liters per minute. This ensures the refrigerant fully evaporates in the battery cooler, absorbing more heat. Furthermore, the battery cooler facilitates heat exchange between the refrigerant and the liquid in the first liquid circuit. Battery coolers typically employ plate heat exchanger structures, offering high heat exchange efficiency.

[0055] For example, under certain operating conditions, the heat exchange area of ​​the battery cooler is 2 square meters. The refrigerant changes from a liquid to a gaseous state within the battery cooler, absorbing a large amount of heat. Assuming the liquid in the first liquid circuit is water-based coolant with an initial temperature of 40°C, its temperature drops to 30°C after passing through the battery cooler. During this process, the refrigerant temperature drops from 30°C to -5°C, completing the heat transfer. In practical implementation, the start-up and operation of the electric air conditioning compressor need to be linked with 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 conditioning 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 matches the heat dissipation requirements of the battery pack. The design of the battery cooler needs to consider heat exchange efficiency and flow resistance, typically employing a multi-channel structure to increase the heat exchange area and improve efficiency. Furthermore, the system operation also needs to consider the influence of ambient temperature.

[0056] For example, in high-temperature environments, the condenser's heat dissipation efficiency may decrease. In such cases, increasing the condenser's fan speed or using water-cooled auxiliary heat dissipation can ensure effective refrigerant condensation. The adjustment precision of the electronic expansion valve also directly affects the system's cooling effect. Typically driven by a stepper motor, it can achieve micron-level opening adjustment, ensuring precise control of the refrigerant flow. Through these measures, the coordinated operation of the refrigerant circuit with the first and second liquid circuits effectively reduces the battery pack temperature, ensuring the battery operates within its optimal operating range. The continuous operation of the electric air conditioning compressor ensures efficient refrigerant circulation, the precise adjustment of the electronic expansion valve ensures the refrigerant flow matches the heat dissipation requirements, and the efficient heat exchange of the battery cooler achieves heat exchange between the refrigerant and the coolant, ultimately cooling the battery pack. This composite cooling system design not only improves the battery pack's heat dissipation efficiency but also extends battery life, enhancing the overall performance and safety of the electric vehicle. Through multi-circuit coordinated operation, the system can flexibly adjust its cooling strategy under different operating conditions, ensuring stable battery pack operation under various environmental conditions.

[0057] Step S106, controlling the operation of at least one cooling circuit according to 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 not greater than the preset temperature difference threshold, then the refrigerant circuit and the first liquid circuit are operated.

[0058] The electronic expansion valve regulates the refrigerant flow according to the instructions of the central control unit. The refrigerant changes from a high-pressure liquid state to a low-pressure gas state at the expansion valve, a process that absorbs a large amount of heat.

[0059] For example, refrigerant R134a changes from a high-pressure liquid state (assuming a pressure of 10 MPa and a temperature of 50°C) to a low-pressure gaseous state (assuming a pressure of 0.5 MPa and a temperature of -10°C) at the expansion valve. The heat absorbed during this phase change effectively reduces the battery pack temperature. The operation of the first liquid circuit is achieved through a battery cooler. The battery cooler contains heat exchange pipes through which the refrigerant flows, exchanging heat with the circulating coolant outside the pipes. Assuming the initial temperature of the coolant is 30°C, after passing through the battery cooler, the temperature drops to 25°C, a process that removes some of the heat from the battery pack. In practice, the central control unit issues control commands based on real-time temperature data and preset parameters.

[0060] For example, when the battery pack temperature is 36°C and the ambient temperature is 25°C, a difference of 11°C, the system determines that the condition of a difference not exceeding 10°C is not met, and therefore does not activate the refrigerant circuit and the first liquid circuit. However, when the battery pack temperature is 34°C and the ambient temperature is 30°C, a difference of 4°C, the condition is met, and the system activates the refrigerant circuit and the first liquid circuit for active cooling. In this way, the battery pack temperature can be effectively controlled within the optimal operating range. Compared to passive cooling, active cooling can reduce the battery pack temperature more quickly and improve cooling efficiency.

[0061] 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 is controlled according to cooling requirements. In active cooling mode, the electronic shut-off valve is closed to ensure the effective operation of the refrigerant circuit; while in passive cooling mode, the electronic shut-off valve is open, allowing the coolant to dissipate heat through the radiator. This multi-circuit coordinated cooling system design not only improves cooling efficiency but also increases the system's flexibility and reliability.

[0062] For example, under complex operating conditions, the system can dynamically adjust the cooling strategy based on changes in real-time temperature and ambient temperature to ensure that the battery pack always operates within its optimal operating range. Through the examples and analysis above, it can be seen that the strategy of controlling the operation of at least one cooling circuit based on defined cooling requirements can effectively address the battery pack temperature control needs under different operating conditions, ensuring the safety and performance of the battery pack, and improving the reliability of the entire vehicle and the user experience.

[0063] 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; adjusting 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.

[0064] Close the electronic shut-off valve to ensure that the refrigerant circuit operates independently from the first liquid circuit.

[0065] For example, when the battery pack temperature exceeds the maximum limit of its optimal operating range but the temperature difference with the ambient temperature is no greater than 10°C, the system automatically closes the electronic shut-off valve to prevent the refrigerant from directly mixing with the first liquid circuit, ensuring cooling efficiency. The electronic shut-off valve can be closed via electromagnetic control; upon receiving a control signal, the valve responds quickly, disconnecting the connection between the two circuits to ensure the refrigerant circulates in an independent circuit, avoiding energy loss. The electric air conditioning compressor then circulates the refrigerant in the refrigerant circuit.

[0066] 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, causing it to release heat in the condenser and condense into a liquid state. The power of the electric air conditioner compressor can be adjusted according to the temperature changes of the battery pack to ensure stable refrigerant flow and pressure 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.

[0067] For example, the electronic expansion valve precisely controls the refrigerant flow rate based on feedback signals from the battery pack temperature sensor, causing 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%, causing the refrigerant temperature at the expansion valve outlet to drop to -10°C and the pressure to drop to 0.5 MPa, ensuring the refrigerant fully absorbs heat in the battery cooler. The battery cooler then facilitates heat exchange between the refrigerant and the liquid in the first liquid circuit.

[0068] For example, the battery cooler incorporates a microchannel heat exchanger. The refrigerant flows through these microchannels, exchanging heat with the coolant in the first liquid circuit. Assuming the initial coolant temperature is 30°C, it rises to 35°C after passing through the battery cooler, while the refrigerant temperature rises from -10°C to 20°C, achieving effective heat transfer from the battery pack to the refrigerant and then to the coolant. In practice, 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 ample heat exchange time. The electronic expansion valve has a response time of 0.1 seconds to ensure rapid adjustment of the refrigerant flow rate, adapting to real-time changes in the battery pack temperature. Why is this necessary? Closing the electronic shut-off valve prevents direct mixing of the refrigerant and coolant, ensuring efficient operation of their respective circuits. The use of an electric air conditioning compressor provides a continuous supply of 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 microchannel design of the battery cooler increases the heat exchange area and improves heat exchange efficiency. What beneficial technical effects does this bring? First, it ensures rapid cooling of the battery pack in high-temperature environments, extending battery life. Second, by precisely controlling refrigerant flow and pressure, it improves the system's energy efficiency ratio and reduces energy consumption. Finally, independent operation of each circuit avoids mutual interference, improving system stability and reliability. In practical applications, this technical solution can be widely used in electric vehicle battery cooling systems to ensure stable battery operation in high-temperature environments, improving vehicle safety and range.

[0069] For example, in high-temperature environments during summer, the battery pack temperature rises rapidly. The system then activates an 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 technology can also be applied to battery cooling systems in energy storage power stations, ensuring the safe operation of large-scale battery packs in high-temperature environments.

[0070] For example, battery packs in energy storage power stations are prone to overheating in high-temperature environments. The system activates an active cooling mode, rapidly reducing the battery pack temperature by precisely controlling the refrigerant flow and pressure, thus preventing thermal runaway. Through various examples and analyses, it can be seen that this technical solution achieves efficient and precise battery cooling through the coordinated work of its components, demonstrating broad application prospects and practical value.

[0071] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for controlling battery cooling during vehicle operation, characterized in that, include: Obtain the real-time temperature of the battery pack; The cooling requirements of the battery pack are determined by comparing the real-time temperature of the battery pack with the maximum limit of the 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. Based on the determined cooling requirements, at least one cooling circuit is controlled to operate. 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. The battery pack is cooled by the controlled cooling circuit so that the temperature of the battery pack is maintained within the optimal operating range; Based on the determined cooling requirements, at least one cooling circuit is controlled to operate, 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 greater than the preset temperature difference threshold, then the first liquid circuit and the second liquid circuit are operated; if the real-time temperature of the battery pack still cannot be effectively reduced, then the refrigerant circuit is operated simultaneously with the first liquid circuit and the second liquid circuit; if, during the simultaneous operation of the refrigerant circuit, the first liquid circuit, and the second liquid circuit, 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 electronic shut-off valve is closed, and only the refrigerant circuit and the first liquid circuit are operated. 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.

2. The method as described in claim 1, characterized in that, The operation of the first liquid circuit and the second liquid circuit includes: Open the electronic shut-off valve; The battery pack water pump drives the flow of liquid in the first liquid circuit and the second liquid circuit; The heat from the liquid in the second liquid circuit is dissipated into the air through the radiator.

3. The method as described in claim 1, characterized in that, The operation of the refrigerant circuit while operating the first liquid circuit and the second liquid circuit includes: The electric air conditioning compressor causes the refrigerant to circulate in the refrigerant circuit; The flow rate of the refrigerant is regulated by the electronic expansion valve; The battery cooler allows the refrigerant to exchange heat with the liquid in the first liquid circuit.

4. The method as described in claim 1, characterized in that, The operation of the refrigerant circuit and the first liquid circuit includes: Close the electronic shut-off valve; The electric air conditioning compressor causes the refrigerant to circulate in the refrigerant circuit; The flow rate of the refrigerant is regulated by the electronic expansion valve; The battery cooler allows the refrigerant to exchange heat with the liquid in the first liquid circuit.

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