New energy automobile secondary circuit integrated thermal management method

Abstract

According to the integrated thermal management method for the secondary circuit of the new energy automobile, mechanical abrasion or electrical faults are accurately recognized by monitoring the rotating speed and the current signal of the main water pump in real time, and the standby water pump is rapidly switched to guarantee circulation continuity of cooling liquid; meanwhile, the opening degree of the electric control valve is dynamically adjusted to optimize flow distribution of each branch, and the temperature of the battery is maintained in a safe interval in combination with multi-point temperature data fusion processing; in addition, by means of branch isolation and bypass channel switching, local faults can be handled in time, and the overall cooling capacity is maintained. According to the invention, the stability and safety of the thermal management system in multiple scenes are obviously improved.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to an integrated thermal management method for the secondary circuit of a new energy vehicle. Background Technology

[0002] The thermal management system of new energy vehicles is a core component that ensures the normal operation of the vehicle's battery, motor, and electronic control unit, directly affecting the vehicle's safety, range, and lifespan. Under various real-world usage scenarios, such as frequent start-stop cycles in urban areas, prolonged high-speed driving, and extreme cold or heat, the heating characteristics of these critical components vary significantly, placing high demands on the real-time performance and accuracy of coolant flow and temperature control.

[0003] Most current thermal management systems rely on a single main water pump to drive coolant circulation, supplying water to the battery, motor, and electronic control unit through fixed or simply preset piping distribution. If the main water pump experiences abnormal speed, sudden current changes, or complete shutdown, the entire cooling circuit quickly loses its circulation capacity, causing coolant to stop flowing and component temperatures to rise sharply. Even under normal main water pump operation, limitations in piping design and valve regulation often result in significant flow imbalances between branches. For example, the battery branch may have insufficient flow while the motor branch has excessive flow, or a branch may experience partial blockage or valve stagnation, preventing other branches from compensating in time. This leads to a contradictory phenomenon of localized overheating and overall reduced cooling capacity. These uneven flow and branch malfunctions frequently occur simultaneously in actual operation, further amplifying the impact of main water pump failure.

[0004] Especially during the alternation of repeated low-speed, high-current discharge and occasional high-speed cruising in urban commuting, battery temperature can rise rapidly in a short period of time, while the thermal load of the motor and electronic control unit exhibits different peak characteristics. If the main water pump suddenly fails, the system cannot maintain any effective cooling circulation, and the risk of temperature runaway increases sharply. Even if the main water pump is still working, if the flow rate of a branch is severely low due to valve abnormalities or pipeline problems, the corresponding components will also overheat due to insufficient heat dissipation, while excessive coolant in other branches will result in energy waste. This mutual constraint between the reliability of the main water pump and the dynamic balance of branch flow makes it difficult for the system to simultaneously ensure that the temperature of all critical components is maintained within a safe range when facing rapid changes in component thermal demand and potential local failures.

[0005] How to maintain continuous and effective circulation of coolant among key components and achieve precise and balanced temperature control even when the main water pump may fail, the branch flow distribution is uneven, and local anomalies exist simultaneously has become a key issue for the stable and reliable operation of the thermal management system of new energy vehicles. Summary of the Invention

[0006] To address the technical problems mentioned above, this invention provides an integrated thermal management method for the secondary circuit of a new energy vehicle, comprising: S1, acquiring real-time operating status data of the main water pump by monitoring its speed and current signals, determining whether the main water pump experiences mechanical wear or electrical faults, and generating a main water pump anomaly identifier; S2, activating a standby water pump switching logic based on the main water pump anomaly identifier, and starting the standby water pump to drive coolant flow when the main water pump anomaly identifier is true; S3, collecting coolant flow rate values, determining whether the coolant flow rate value reaches a preset flow rate threshold, and generating a flow balance state; S4, performing flow distribution adjustment of the battery cooling circuit based on the flow balance state, and adjusting the opening of the electronically controlled valve when the flow balance state is unstable. S5. Obtain the dynamic flow allocation result; S6. Obtain the flow data of each branch in the dynamic flow allocation result, and determine whether there is an abnormal branch by comparing the flow of each branch with the corresponding standard range. If there is, determine the location of the faulty branch; S7. Isolate the abnormal branch channel according to the location of the faulty branch, close the corresponding valve and switch to the backup channel to form a cooling path after isolation; S8. Obtain the temperature data of each cooling circuit from the cooling path after isolation, perform fusion processing on the temperature data of each cooling circuit, and generate a minimum cooling guarantee level if the temperature is maintained within the safe range; S9. Adjust the overall thermal management parameters according to the minimum cooling guarantee level. When the minimum cooling guarantee level is lower than the cooling threshold, adjust the coolant pumping rate to determine the stable operation configuration of the system.

[0007] Furthermore, step S1 includes: step S11, calculating the fluctuation amplitude of the speed signal and the abrupt change characteristics of the current signal; step S12, when the fluctuation amplitude exceeds the fluctuation amplitude threshold or the current signal shows abrupt change characteristics, determining that the main water pump has mechanical wear or electrical fault, and generating a true main water pump abnormality flag.

[0008] Furthermore, step S3 includes: step S31, performing smoothing filtering on multiple continuously collected coolant flow rates to obtain filtered flow rates; step S32, comparing the filtered flow rates with a flow rate threshold; and step S33, when the filtered flow rates are continuously lower than the flow rate threshold, generating an unstable flow balance state.

[0009] Furthermore, step S4 includes: step S41, calculating the target opening adjustment amount of each electronically controlled valve based on the flow deviation of each branch when the flow balance state is unstable; step S42, gradually changing the opening of the electronically controlled valve according to the preset adjustment step size; step S43, monitoring the change of coolant flow value in real time until the coolant flow value tends to be near the flow threshold, and determining the dynamic flow distribution result.

[0010] Furthermore, step S5 includes: step S51, when the flow rate of any branch is lower than the lower limit of its standard range or higher than the upper limit of its standard range, marking the branch as a temporary abnormal branch; step S52, counting the number of times the temporary abnormal branch is marked within multiple consecutive sampling periods; step S53, when the number of markings exceeds the preset number of confirmations, determining the branch as a faulty branch.

[0011] Furthermore, step S6 includes: step S61, opening the valve of the backup bypass channel that is connected in parallel with the faulty branch; step S62, monitoring the flow rate of the backup bypass channel; step S63, confirming the formation of the isolation cooling path after the flow rate of the backup bypass channel reaches the preset bypass flow rate requirement.

[0012] Furthermore, step S7 includes: step S71, collecting temperature measurement values ​​from multiple temperature sensors in the isolated cooling path; step S72, performing a weighted average calculation on the multiple temperature measurement values ​​to obtain a fusion temperature value; step S73, correcting the fusion temperature value using a preset ambient temperature correction coefficient; and step S74, determining whether the corrected fusion temperature value is maintained within a safe range and generating a minimum cooling guarantee level.

[0013] Further, step S8 includes: step S81, when the minimum cooling guarantee level is lower than the cooling threshold, determining the direction of increase or decrease of the coolant pumping rate; step S82, calculating the adjustment range of the coolant pumping rate based on the degree to which the fusion temperature value deviates from the safe range; step S83, changing the duty cycle of the drive signal of the standby water pump to achieve continuous adjustment of the coolant pumping rate; step S84, repeating step S7 until the minimum cooling guarantee level reaches or exceeds the cooling threshold.

[0014] The technical solution provided by this invention has the following beneficial effects:

[0015] This invention discloses an integrated thermal management method for the secondary circuit of new energy vehicles. Addressing the complex thermal management requirements of batteries, motors, and electronic control units in new energy vehicles operating under urban commuting, high-speed cruising, and extreme weather conditions, and the susceptibility to main water pump failures, uneven flow, and branch circuit anomalies, this invention proposes a systematic solution. By real-time monitoring of the main water pump's speed and current signals, this invention accurately identifies mechanical wear or electrical faults and quickly switches to a backup water pump to ensure continuous coolant circulation. Simultaneously, it dynamically adjusts the opening of electronically controlled valves to optimize flow distribution in each branch circuit, and combines multi-point temperature data fusion processing to ensure the battery temperature remains within a safe range. Furthermore, through branch isolation and bypass channel switching, it promptly addresses localized faults and maintains overall cooling capacity. Ultimately, this invention significantly improves the stability and safety of the thermal management system across multiple scenarios, effectively reduces the risk of overheating, extends the service life of key components, and provides reliable assurance for the entire lifecycle operation of new energy vehicles. Attached Figure Description

[0016] Figure 1 This is a flowchart of an integrated thermal management method for the secondary circuit of a new energy vehicle according to the present invention. Detailed Implementation

[0017] To further understand the content of this invention, a detailed description of the invention is provided in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0018] like Figure 1 As shown, this invention provides an integrated thermal management method for the secondary circuit of a new energy vehicle, aiming to ensure the stability and safety of the system under various operating conditions by real-time monitoring and dynamic adjustment of the cooling system's operating status. The implementation process of this invention is described in detail below with reference to specific embodiments to make the objectives, technical solutions, and advantages of this invention clearer. In one embodiment, the method provided by this invention mainly addresses the thermal management needs of the secondary circuit in new energy vehicles. It achieves reliable operation of the cooling system through comprehensive monitoring and adjustment of the main water pump, standby water pump, and the flow rates of each branch circuit. The secondary circuit of a new energy vehicle typically involves the thermal management of key components such as the battery, motor, and electronic control unit, and its operating status directly affects the vehicle's performance and safety. This method, through multi-level monitoring and control logic, ensures stable circulation and temperature control of the coolant, providing continuous thermal management support for the system. It should be noted that this method is applicable to different types of new energy vehicles, including pure electric vehicles and plug-in hybrid electric vehicles, covering various usage scenarios such as urban commuting, high-speed cruising, and operation under extreme weather conditions.

[0019] Specifically, the method includes: S1, by monitoring the speed signal and current signal of the main water pump, obtaining real-time operating status data of the main water pump, determining whether the main water pump has mechanical wear or electrical faults, and generating an abnormality identifier for the main water pump.

[0020] Specifically, the main water pump, as the core power component of the secondary cooling system, is crucial to the stability of the entire system. In actual operation, the main water pump may experience problems such as bearing wear, impeller jamming, or short circuits in the motor coil due to prolonged use, affecting the normal circulation of coolant. Therefore, real-time monitoring of its speed and current signals becomes a key means of assessing its health status. The speed signal can be acquired by a speed sensor installed on the water pump output shaft, typically recorded in revolutions per minute (RPM), while the current signal is collected by a current sensor, reflecting the workload of the water pump motor. In one possible implementation, acquiring real-time operating status data of the main water pump involves continuous sampling of the speed and current signals. For example, during vehicle operation, the system collects speed and current data at a frequency of 10 times per second and stores this data in the cache of the onboard control unit for subsequent analysis. The speed signal can be acquired using a Hall effect sensor, which can accurately sense the rotation frequency of the water pump shaft, while the current signal acquisition relies on a current transformer connected in series in the motor power supply circuit. By recording this data in real time, the system can quickly capture subtle changes in the operating status of the main water pump, providing a reliable basis for subsequent fault diagnosis.

[0021] Optionally, this step may also include: step S11, calculating the fluctuation amplitude of the speed signal and the abrupt change characteristics of the current signal.

[0022] Specifically, regarding the analysis of the speed signal, the system calculates the average value and standard deviation of the speed signal within a certain time window to assess its stability. For example, if the standard deviation of the speed signal exceeds the preset normal range within a 5-second time window, it indicates that the water pump may have mechanical vibration or impeller imbalance. Furthermore, the system also monitors for instantaneous drops or surges in the speed signal, which are usually related to mechanical jamming or sudden changes in external load. For the current signal, the system analyzes its waveform characteristics, focusing on the presence of periodic fluctuations or abnormal spikes, which are often related to internal short circuits or overloads in the motor. Through multi-dimensional analysis of the speed and current signals, the system can comprehensively assess the operational health of the main water pump. In step S12, when the fluctuation amplitude exceeds the fluctuation amplitude threshold or the current signal exhibits a sudden change, it is determined that the main water pump has mechanical wear or an electrical fault, and a true main water pump abnormality flag is generated.

[0023] When determining whether the main water pump has mechanical wear or electrical faults, the system comprehensively compares historical operating data with currently collected data. For example, if the current speed signal shows a continuous drop below the normal operating range, and the current signal shows an abnormally increasing trend, the system will initially determine that the water pump may have mechanical wear, such as increased bearing friction leading to a decrease in speed, while the motor increases current consumption to maintain output power. On the other hand, if the current signal shows a momentary jump, while the speed signal does not change significantly, it may indicate an electrical fault, such as a partial short circuit in the motor windings causing abnormal current. Through this multi-parameter joint analysis, the system can accurately identify the fault type and generate a corresponding main water pump fault identifier. This identifier is usually stored in Boolean form; a true value indicates that the water pump is abnormal, and a false value indicates that the water pump is operating normally. In one embodiment, the generation process of the main water pump fault identifier can be further modified by incorporating environmental factors. For example, in low-temperature environments, the starting speed of the water pump may be lower due to increased coolant viscosity. In this case, the system will dynamically adjust the normal range of the speed signal based on data collected by the ambient temperature sensor to avoid misjudgment. In addition, the system records the cumulative operating time of the water pump as an auxiliary basis for judging mechanical wear. Assuming a water pump has been running continuously for more than 5000 hours, the system will increase its sensitivity to speed fluctuations and current anomalies to detect potential problems earlier. In this way, the system can maintain high diagnostic accuracy under different operating conditions, providing reliable support for subsequent control decisions. S2, the standby water pump switching logic is activated based on the main water pump anomaly flag. When the main water pump anomaly flag is true, the standby water pump is started to drive the coolant flow.

[0024] Specifically, the backup water pump, as a redundant design of the main water pump, is usually in standby mode. Its main function is to quickly take over the coolant circulation task when the main water pump fails, ensuring that the secondary circuit does not overheat due to power interruption. In new energy vehicles, components such as batteries and motors are temperature-sensitive. If the coolant stops flowing, it may cause a rapid temperature rise in a short period of time, even leading to system shutdown or safety accidents. Therefore, the timely start-up of the backup water pump is crucial to system reliability. In one possible implementation, when the main water pump malfunction indicator is true, the vehicle control unit immediately sends a start command to the backup water pump's drive module, while simultaneously cutting off the power supply to the main water pump to prevent further damage. The startup process of the backup water pump usually takes 1 to 2 seconds. During this period, the system monitors the coolant pressure changes in the circuit through pressure sensors to ensure that the backup water pump has been properly engaged.

[0025] If the pressure sensor detects that the loop pressure has returned to the normal range, it indicates that the backup water pump has successfully taken over the coolant circulation task. At this time, the system will record the time and status of the switching event for subsequent maintenance analysis. If the loop pressure has not returned to normal, the system will trigger further fault diagnosis to check whether there is a problem with the backup water pump itself. If the backup water pump also fails, an alarm will be issued. In one embodiment, the startup of the backup water pump can also be optimized in conjunction with the vehicle's operating conditions. For example, when the vehicle is driving at low speed, the thermal load of the battery and motor is low, and the system can start the backup water pump at a lower initial speed to reduce energy consumption. In high-speed driving or fast charging scenarios, the thermal load is high, and the system will start the backup water pump at maximum speed to ensure that the coolant flow rate quickly reaches the required level. In addition, the system will also adjust the operating strategy of the backup water pump according to the coolant temperature data. If the temperature is close to the safe upper limit, the backup water pump will continue to operate at high power until the temperature drops to a safe range. Through this dynamic adjustment, the system can reduce energy consumption as much as possible while ensuring cooling effect and improving the overall vehicle energy efficiency. It should be noted that the switching logic of the backup water pump also includes continuous monitoring of the status of the main water pump. For example, after the backup water pump starts, the system periodically re-checks the main water pump's speed and current signal. If the main water pump has returned to normal, the system attempts to switch back to main water pump operation to extend the backup pump's lifespan. This closed-loop control mechanism of main / backup switching maintains the continuity of the cooling system throughout the dynamic process of fault occurrence and recovery. Furthermore, during the switching process, the system sends alerts to the driver via the in-vehicle display or mobile application, informing them of the current cooling system status and allowing the driver to take timely action. In one possible implementation, the backup water pump's activation can also be linked to the vehicle's fault protection mode. For example, when the main water pump malfunction indicator is true, the system not only activates the backup water pump but also limits the vehicle's maximum speed or charging power to reduce heat load and pressure on the cooling system. This comprehensive protection strategy effectively prevents system overheating in the early stages of a fault, buying time for subsequent repairs. Simultaneously, the system uploads fault information to a cloud server, facilitating remote diagnosis and dispatch support from automakers or repair personnel. Through this multi-layered protection mechanism, the system maximizes vehicle operational safety in the event of a main water pump failure. S3: Collect coolant flow rate value, determine whether the coolant flow rate value has reached the preset flow rate threshold, and generate a flow balance state.

[0026] Specifically, after the standby water pump starts, the coolant flow rate directly affects the cooling effect of the secondary circuit. Insufficient flow may lead to a decrease in the cooling capacity of some branches, resulting in localized overheating. Therefore, real-time acquisition and analysis of coolant flow rate values ​​via flow sensors is crucial for ensuring stable system operation. Flow sensors are typically installed at the outlet of the main circulation loop and can accurately measure the volume of coolant passing through per unit time. In one embodiment, the acquisition and processing of coolant flow rate values ​​includes several detailed steps.

[0027] Step S31: Perform smoothing filtering on the multiple continuously collected coolant flow rates to obtain the filtered flow rate values.

[0028] The system collects data from the flow sensor 5 times per second to obtain a continuous sequence of coolant flow values. To reduce noise interference, the system performs smoothing filtering on these data, for example, by using a moving average filtering method and taking the average of the most recent 10 sampling points as the filtered flow value.

[0029] Step S32: Compare the filtered flow rate value with the flow rate threshold.

[0030] The flow rate threshold is typically determined based on vehicle design parameters and cooling requirements, for example, 10 liters per minute. Step S33: When the filtered flow rate value remains below the flow rate threshold, the generated flow balance state is unstable.

[0031] If the filtered flow rate remains below the flow threshold for multiple consecutive sampling periods, the system determines the flow balance state to be unstable and generates a corresponding status indicator. If the flow rate recovers to near or above the flow threshold, the status indicator is stable. In one possible implementation, coolant temperature and ambient temperature can be used as auxiliary parameters to determine the flow balance state. For example, in a high-temperature environment, the viscosity of the coolant may decrease, causing the flow rate to be slightly higher than normal. In this case, the system will dynamically correct the flow threshold based on temperature sensor data to avoid misjudgment. Furthermore, the system records the trend of flow rate changes. If a continuous downward trend is detected, even if the flow rate is not yet below the flow threshold, an unstable status indicator will be generated in advance so that adjustment measures can be taken as early as possible. Through this multi-parameter comprehensive analysis, the system can more accurately assess the actual state of the coolant flow. It should be noted that the generation of the flow balance state is not only used for subsequent flow distribution adjustments but can also serve as a reference indicator for the system's health status. For example, if the flow rate consistently fails to reach the flow threshold after the standby water pump starts, it may indicate that the standby water pump itself has insufficient performance or that there is a blockage in the circuit. At this point, the system triggers further diagnostic procedures to check the water pump output power and pipeline pressure distribution in order to pinpoint the root cause of the problem. Through this closed-loop monitoring mechanism, the system can detect potential risks in the early stages of flow anomalies, preventing further deterioration. In one embodiment, the system can also differentiate its flow balance judgment based on the vehicle's operating scenario. For example, in a fast-charging scenario, where the battery heat load is high, the system will increase the flow threshold requirement to ensure the coolant can effectively remove heat. In a daily commuting scenario, where the heat load is low, the system can appropriately lower the flow threshold to reduce water pump energy consumption. Furthermore, the system will adjust its judgment logic based on the vehicle's battery charge status. If the charge is low, the system will prioritize cooling, and even if the flow rate is slightly below the threshold, it will not easily be classified as unstable to avoid increased energy consumption due to frequent adjustments. Through this scenario-based flow management strategy, the system can achieve a balance between cooling effect and energy efficiency under different operating conditions. In one possible implementation, the installation location and number of flow sensors can also be optimized according to the vehicle design. For example, in some vehicle models, the system installs flow sensors in the main circulation loop and each branch loop to more accurately monitor overall and local flow distribution. Through comprehensive analysis of multi-point flow data, the system can gain a more complete understanding of the coolant flow status, providing richer data support for subsequent flow distribution adjustments. Furthermore, the system periodically self-calibrates the flow sensors to eliminate measurement deviations caused by long-term use, ensuring data accuracy. Through this multi-layered monitoring approach, the system can effectively improve the reliability of flow balance state judgment. In one embodiment, the system can also incorporate a historical data comparison mechanism for the flow balance state generation process.For example, the system compares the currently collected flow rate with the average flow rate over the past week. If the current value is significantly lower than the historical average, even if it is not below the flow threshold, an unstable state indicator will be generated. This historical data-based analysis method helps the system detect potential trends in flow anomalies earlier, allowing more reaction time for subsequent adjustments. Furthermore, the system correlates flow data with pump operating parameters. If a mismatch is found between flow anomalies and pump speed changes, potentially indicating pipe leaks or blockages, the system will trigger a pressure test to pinpoint the fault. Through this multi-dimensional data analysis, the system significantly improves the sensitivity and accuracy of flow monitoring. It should be noted that the logic for determining flow balance can also be dynamically adjusted based on the vehicle's age. For example, for older vehicles, the system will appropriately lower the flow threshold to accommodate the aging characteristics of the pump and pipes, avoiding frequent alarms due to hardware performance degradation. Simultaneously, the system records the time and environmental conditions of each flow anomaly event for subsequent analysis of system aging trends. Through this adaptive adjustment mechanism, the system can maintain high thermal management efficiency throughout the vehicle's entire lifecycle, providing users with continuous and reliable operational assurance. It should be noted that the process of generating the flow balance state also includes handling outlier data. For example, if the flow sensor collects data that deviates significantly from the normal range at a certain moment, the system will mark it as an outlier and perform interpolation correction by referring to the flow data at previous and subsequent time points to avoid single-point anomalies interfering with the overall judgment. In addition, the system will periodically check the operating status of the sensors. If a sensor malfunction is found, it will switch to a backup sensor or estimate the flow value based on the pump speed to ensure the continuity of flow monitoring. Through this robust design, the system can still maintain an accurate assessment of the flow balance state even in the event of sensor malfunction or data loss. S4, the flow distribution of the battery cooling circuit is adjusted according to the flow balance state. When the flow balance state is unstable, the opening of the electronically controlled valve is adjusted to obtain a dynamic flow distribution result.

[0032] Specifically, when the flow balance is unstable, it indicates a deviation in the overall circulation capacity of the coolant. The system needs targeted adjustments to the battery cooling branch to ensure the uniformity of temperature across the battery cells. The battery cooling circuit typically includes multiple parallel branches, each corresponding to a different area or module of the battery pack. Electronically controlled valves are installed at the inlet of each branch, and the coolant flow is redistributed by changing the valve opening, thereby achieving balanced heat removal. In one embodiment, the process of adjusting the electronically controlled valves is divided into several consecutive stages.

[0033] Step S41: Calculate the target opening adjustment amount of each electrically controlled valve based on the flow deviation of each branch when the flow balance is unstable.

[0034] When the flow balance status is marked as unstable, the system first reads the real-time flow data of each branch and calculates the deviation between this data and the target flow range of each branch. Branches with larger deviation values ​​will be prioritized for adjustment. For example, if the flow rate of the branch containing the front battery module is significantly lower than the flow rate of the branch containing the rear module is higher than the flow rate, the system will prioritize increasing the opening of the valve in the front branch while appropriately decreasing the opening of the valve in the rear branch to achieve flow rebalancing. Step S42: Gradually change the opening of the electronically controlled valves according to the preset adjustment step size.

[0035] Typically, each adjustment is controlled within 5% to 8% of the total opening to avoid system oscillations or drastic fluctuations in local flow rates caused by excessive adjustments at once. After each adjustment, the system waits approximately 3 to 5 seconds for stabilization to allow the coolant flow to fully respond to the valve action, and then collects the flow values ​​of each branch again for verification. Step S43 involves real-time monitoring of coolant flow rate changes until the coolant flow rate approaches the flow threshold, thus determining the dynamic flow distribution result.

[0036] The system monitors coolant flow rate changes in real time until the flow rate of each branch gradually approaches its target range. When the flow deviation of all branches converges within the preset allowable error, the system stops the current adjustment action and records the current valve opening combination as a dynamic flow allocation result. This result includes not only the opening percentage of each electronically controlled valve but also the corresponding branch flow rate value and the average temperature change trend of each area of ​​the battery. In one possible implementation, the system can adopt different adjustment strategies for different battery thermal runaway risk levels. For example, when the battery management system detects that the temperature difference of a single cell in a certain area exceeds 8°C, the system will enter a fast adjustment mode, and the adjustment step size can be appropriately widened to 10% to restore temperature uniformity more quickly. Under normal temperature control scenarios, the system maintains a more conservative step size setting, prioritizing the smoothness of the adjustment process and preventing mechanical wear and increased energy consumption caused by frequent valve operations. It should be noted that the adjustment logic of the electronically controlled valves also needs to consider the constraint of the total coolant flow rate. When the standby water pump output flow rate is already low, even if there are significant deviations in some branches, the system will not increase the valve opening of any branch indefinitely. Instead, it will prioritize the cooling needs of critical high-temperature branches while freeing up flow resources by reducing the opening of non-critical branches. This priority-based flow redistribution method can maximize battery safety when the total flow rate is limited. In one embodiment, for large-capacity battery packs in long-range vehicles, the system can subdivide the battery cooling circuit into more branches. For example, the battery pack can be divided longitudinally into three sections (front, middle, and rear), and each section can be further divided laterally into left and right sides, resulting in a total of six independent adjustable branches. Each branch is equipped with an independent electronically controlled proportional valve. The system calculates the flow demand weight of each branch based on the data fed back from the temperature sensors of each section. Branches with higher weights will receive larger valve opening increments, thereby achieving more refined regional thermal management. S5: Obtain the flow data of each branch in the dynamic flow distribution result. By comparing the flow rate of each branch with the corresponding standard range, determine whether there are abnormal branches. If so, determine the location of the faulty branch.

[0037] Specifically, after the dynamic traffic allocation is completed, the system continuously collects the actual traffic flow of each branch and compares it with the standard traffic flow range of that branch under the current operating conditions. The standard range is usually determined during the vehicle calibration phase, taking into account various factors such as different ambient temperatures, battery SOC, and charge / discharge rates. In one possible implementation, the judgment of abnormal branches adopts a multi-cycle confirmation mechanism.

[0038] Specifically, this step also includes:

[0039] Step S51: When the flow rate of any branch is lower than the lower limit of its standard range or higher than the upper limit of its standard range, the branch is marked as a temporary abnormal branch.

[0040] When the flow rate of any branch is lower than the lower limit or higher than the upper limit of its standard range in a single sampling period, the system first marks it as a temporary abnormal branch, rather than immediately confirming it as a fault.

[0041] Step S52: Count the number of times temporary abnormal branches are marked within multiple consecutive sampling periods.

[0042] Optionally, the system counts the number of temporary anomaly markers for this branch within 8 to 12 consecutive sampling periods.

[0043] Step S53: When the number of markings exceeds the preset number of confirmations, the branch is determined to be a faulty branch.

[0044] Only when the number of markings exceeds a preset number of confirmations (e.g., 10 consecutive times or 15 cumulative times) is the branch officially identified as a faulty branch, and its specific location number is recorded. For example, in a high-temperature fast charging scenario during summer, if the flow rate of the branch in the middle of the battery remains consistently low, and multiple adjustments to the valve opening fail to restore it to the lower limit of the standard range, the system will determine that the branch has a blockage or valve jamming fault. In this case, the system will output the branch number (e.g., branch number B3) as the location of the faulty branch for subsequent isolation operations. It should be noted that the standard range itself is dynamically changing. The system will adjust the upper and lower limits of each branch in real time based on parameters such as the current ambient temperature, coolant temperature, average battery temperature, and charging / discharging power. For example, when the ambient temperature exceeds 35°C and the battery is charging at 1C or higher, the lower limit of the standard flow rate will be increased by 10% to 15% to cope with higher heat dissipation requirements. This adaptive standard range design can significantly reduce the probability of misjudgment due to changes in operating conditions. In one embodiment, the system can also perform preliminary classification based on the direction of flow deviation to distinguish the type of branch anomaly. If the flow rate of a certain branch is consistently significantly higher than the upper limit, while the flow rates of other branches are relatively low, it is possible that the valve on that branch cannot be closed or that there is a bypass short circuit. If the flow rate is consistently significantly lower than the lower limit, it is more likely that the flow loss is caused by the valve being stuck at a small opening, partial blockage in the pipeline, or leakage at the joint. Through this analysis of the direction of deviation, the system can preliminarily infer possible fault modes while determining the location of the fault, providing reference information for subsequent maintenance. S6, based on the location of the faulty branch, isolate the abnormal branch channel, close the corresponding valve, and switch to the backup channel to form a cooling path after isolation.

[0045] Specifically, once a branch is identified as faulty, the system's primary task is to quickly disconnect it from the main cooling cycle to prevent the faulty branch from further affecting the overall flow distribution or causing coolant leakage. Simultaneously, to ensure that the battery area corresponding to this branch still receives a certain level of cooling, the system activates a pre-designed backup bypass channel, allowing coolant to continue flowing through the vicinity of the faulty area via other paths. In one possible implementation, the isolation operation includes the following sequential actions:

[0046] Step S61: Open the spare bypass channel valve that is connected in parallel with the faulty branch.

[0047] The system immediately drives the electrically controlled valve corresponding to the faulty branch to the fully closed state, and at the same time sends an opening command to the backup bypass valve of that branch. The bypass channel is usually a small-diameter rigid pipe or flexible pipe, arranged in parallel with the main branch, and can provide about 30% to 50% of the original design flow after the main channel is closed.

[0048] Step S62: Monitor the flow rate of the backup bypass channel.

[0049] The system monitors whether the bypass flow rate has reached the preset minimum guaranteed value through an auxiliary flow sensor installed on the bypass channel.

[0050] Step S63: When the flow rate of the backup bypass channel reaches the preset bypass flow rate requirement, the isolation cooling path is confirmed to be formed.

[0051] Once the bypass flow stabilizes within the required range, the system confirms that the isolated cooling path has been successfully established and updates the current path status to "branch isolation mode". In one embodiment, for vehicles with multiple relatively independent cooling plates or cooling coils inside the battery pack, the system can treat each cooling plate as an independent branch. When the branch corresponding to a certain cooling plate is isolated, the bypass channel will directly connect to the upstream and downstream manifolds of that cooling plate, ensuring that the coolant can still flow through the surface of that cooling plate, but the flow rate is limited to a safe and controllable range. This design can maintain more than 80% of the overall cooling capacity of the battery pack in the event of a single branch failure, avoiding thermal runaway of the entire pack due to a single point of failure. It should be noted that the isolation operation also needs to consider the impact on other normal branches. While closing the valve of the faulty branch, the system will appropriately increase the valve opening of the remaining normal branches to compensate for the reduction in total flow and maintain the overall flow of the main circulation loop basically stable. This compensation adjustment is usually completed gradually in 2 to 3 steps, with each increase not exceeding 5% of the total flow, to avoid new flow anomalies in other branches due to sudden compensation. In one possible implementation, the backup bypass channel can also adopt different activation strategies depending on the location of the faulty branch. For example, when a branch near the edge of the battery pack fails, the bypass channel prioritizes the shortest path to reduce flow resistance; when a branch located in the center of the battery pack fails, the system will prioritize the parallel activation of multiple bypass channels to ensure sufficient coolant supply. This location-based adaptive bypass strategy can maximize the temperature uniformity of the battery area under different fault scenarios. S7, obtain the temperature data of each cooling circuit from the isolated cooling path, perform fusion processing on the temperature data of each cooling circuit, determine whether the temperature is maintained within the safe range, and generate the minimum cooling guarantee level.

[0052] Specifically, after branch isolation, the flow characteristics of the cooling path have changed, and the heat dissipation capacity of each area varies. Therefore, it is necessary to comprehensively evaluate the actual reliability of the current cooling system using multi-point temperature data. The temperature data mainly comes from temperature sensors distributed at different locations in the battery pack, including surface temperature sensors, NTC sensors inside the module, and temperature sensors at the inlet and outlet of the cooling plate. In one embodiment, the fusion processing includes the following steps:

[0053] Step S71: Collect temperature measurement values ​​from multiple temperature sensors in the isolated cooling path.

[0054] The system simultaneously collects real-time measurements from at least 12 to 20 temperature sensors along the isolated path. These sensors cover all key areas of the battery pack, including the top, middle, bottom, front, back, left, and right sides.

[0055] Step S72: Calculate the weighted average of multiple temperature measurements to obtain the fusion temperature value.

[0056] A weighted average is calculated for all valid temperature measurements, with sensors closer to high-temperature risk areas given higher weights. For example, the weight of sensors in areas where the individual temperature is close to 45°C can be increased by 1.5 times, while the weight of sensors in areas with lower temperatures is reduced accordingly.

[0057] Step S73: Correct the fusion temperature value by combining it with a preset ambient temperature correction coefficient.

[0058] The weighted average value is corrected by incorporating correction factors for current ambient temperature and solar radiation intensity to eliminate the interference of environmental factors on the measurement.

[0059] Step S74: Determine whether the fusion temperature is maintained within the safe range based on the corrected fusion temperature value, and generate the minimum cooling guarantee level.

[0060] The corrected fusion temperature value is compared with the preset upper and lower limits of the safety range. If the fusion temperature remains within the safety range, the minimum cooling guarantee level is marked as "sufficient"; if it approaches or exceeds the upper limit, it is marked as "critical" or "insufficient". It should be noted that the quantification of the minimum cooling guarantee level can be done in a graded manner. For example, it can be divided into levels 1 to 5, where level 1 indicates extremely insufficient cooling capacity, potentially leading to thermal runaway risk in a short period; level 5 indicates sufficient cooling capacity, supporting high-power long-term operation. The system dynamically determines the current level based on the degree and duration of the fusion temperature deviation from the safety range. This graded quantification method facilitates subsequent linkage with the vehicle's power control strategy. In one possible implementation, when the system is in branch isolation mode, the temperature fusion calculation will also additionally consider the flow weight of each branch. For example, temperature sensor data corresponding to branches with significantly reduced flow will be given higher attention. If the temperature rise rate in this area accelerates significantly, even if the overall fusion temperature is still within the safety range, the system will lower the cooling guarantee level in advance to warn of potential risks. Through this flow-temperature joint evaluation mechanism, the system can detect potential local overheating hazards after isolation earlier. S8, adjust the overall thermal management parameters according to the minimum cooling guarantee level. When the minimum cooling guarantee level is lower than the preset cooling threshold, adjust the coolant pumping rate to determine the stable operating configuration of the system. Specifically, when the minimum cooling guarantee level drops to a critical or insufficient state, the system needs to increase the output capacity of the backup water pump to compensate for the cooling capacity loss caused by branch isolation, thereby pulling the battery temperature back to a safe range. Optionally, this step also includes:

[0061] Step S81: When the minimum cooling guarantee level is lower than the cooling threshold, determine the direction of increase or decrease of the coolant pumping rate.

[0062] The system first determines the direction of coolant pumping rate adjustment. If the melting temperature is higher than the median of the safe range, the pumping rate is increased; if it is close to the lower limit, it is appropriately reduced to save energy.

[0063] Step S82: Calculate the adjustment range of the coolant pumping rate based on the degree to which the fusion temperature value deviates from the safe range.

[0064] The adjustment ratio of the pumping rate is calculated based on the extent to which the fusion temperature deviates from the safe range and the current battery charging / discharging power. For example, when the fusion temperature exceeds the safe upper limit by 3°C and the battery is charging at 0.8C, the system may need to increase the pumping rate to 120% to 135% of the original set value.

[0065] Step S83: Change the duty cycle of the drive signal of the standby water pump to achieve continuous adjustment of the coolant pumping rate.

[0066] Continuous linear adjustment of the pumping rate can be achieved by changing the duty cycle of the PWM drive signal of the standby water pump motor.

[0067] Step S84: Repeat step S7 until the minimum cooling guarantee level reaches or exceeds the cooling threshold.

[0068] After adjustment, the system re-executes temperature acquisition and fusion processing, repeating the above judgment and adjustment until the minimum cooling guarantee level recovers to above the cooling threshold or reaches an acceptable stable state. In one possible implementation, the pumping rate adjustment also needs to be coordinated with the vehicle's power requirements. When the vehicle is in a high-power discharge state, even if the cooling guarantee level is slightly low, the system will prioritize maintaining a higher pumping rate to ensure power output safety; while when the vehicle is parked for charging or cruising at low power, the system allows for a slight reduction in the pumping rate if the cooling guarantee level is just met, in order to extend the driving range. This dynamic balancing strategy based on the actual usage needs of the vehicle can achieve a good trade-off between safety and economy. It should be noted that the entire adjustment process adopts a closed-loop control method. After each change in pumping rate, the system waits for approximately 10 to 20 seconds of temperature response time to reassess the minimum cooling guarantee level. If the guarantee level still does not improve significantly after three consecutive adjustments, the system will trigger higher-level protection measures, such as limiting the maximum charge and discharge rate of the battery or requesting the driver to stop and check. Through this closed-loop mechanism with fail-safe protection, the system can maintain the battery's safe operating state for as long as possible even as the hardware gradually degrades. In one embodiment, for thermal management needs in extreme scenarios, such as prolonged fast charging under continuous high temperatures, the system can set the upper limit of the pumping rate adjustment to 150% to 180% of the normal value, and simultaneously activate all available bypass channels, prioritizing the overall flow supply even if some branches have minor anomalies. At this time, the cooling threshold judgment standard for the minimum cooling guarantee level will also be relaxed accordingly, allowing the fusion temperature to approach 48°C for a short period of time, in exchange for shortening the fast charging time and improving the user experience. This scenario-adaptive extreme operating mode can maximize the satisfaction of users' needs for rapid energy replenishment without sacrificing safety.

[0069] If the technical solution of this application involves personal information, the product using this solution has clearly informed the user of the personal information processing rules and obtained the user's voluntary consent before processing the personal information. If sensitive personal information is involved, the user's separate consent has been obtained before processing, and the "express consent" requirement is met. For example, a clear sign is placed at the collection device such as a camera to inform the user that they have entered the collection area, and the user's voluntary entry is considered as consent; or the processing device clearly indicates the processing rules and obtains authorization through pop-up windows or by asking the user to upload information themselves. The personal information processing rules include the processor, the purpose of processing, the processing method, and the types of personal information.

[0070] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for integrated thermal management of the secondary circuit in a new energy vehicle, characterized in that, include: S1. By monitoring the speed and current signals of the main water pump, real-time operating status data of the main water pump is obtained to determine whether there is mechanical wear or electrical fault in the main water pump, and an abnormality flag is generated for the main water pump; S2. The standby water pump switching logic is activated according to the main water pump abnormality flag. When the main water pump abnormality flag is true, the standby water pump is started to drive the coolant flow; S3. The coolant flow rate value is collected, it is determined whether the coolant flow rate value has reached the preset flow rate threshold, and a flow balance state is generated; S4. Adjust the flow distribution of the battery cooling circuit according to the flow balance state. When the flow balance state is unstable, adjust the opening of the electronically controlled valve to obtain the dynamic flow distribution result. S5. Obtain the flow data of each branch in the dynamic flow distribution result. By comparing the flow of each branch with the corresponding standard range, determine whether there is an abnormal branch. If so, determine the location of the faulty branch. S6. Isolate the abnormal branch channel according to the location of the faulty branch, close the corresponding valve and switch to the backup channel to form an isolated cooling path. S7. Obtain the temperature data of each cooling circuit from the isolated cooling path. Perform fusion processing on the temperature data of each cooling circuit. If the temperature is maintained within the safe range, generate the minimum cooling guarantee level. S8. Adjust the overall thermal management parameters according to the minimum cooling guarantee level. When the minimum cooling guarantee level is lower than the cooling threshold, adjust the coolant pumping rate to determine the stable operation configuration of the system.

2. The method as described in claim 1, characterized in that, Step S1 includes: Step S11, calculating the fluctuation amplitude of the speed signal and the abrupt change characteristics of the current signal; Step S12, when the fluctuation amplitude exceeds the fluctuation amplitude threshold or the current signal shows abrupt change characteristics, determining that the main water pump has mechanical wear or electrical fault, and generating a true main water pump abnormality flag.

3. The method as described in claim 1, characterized in that, Step S3 includes: Step S31, performing smoothing filtering on multiple continuously collected coolant flow rates to obtain filtered flow rates; Step S32, comparing the filtered flow rates with a flow rate threshold; Step S33, when the filtered flow rates are continuously lower than the flow rate threshold, generating an unstable flow balance state.

4. The method as described in claim 1, characterized in that, Step S4 includes: Step S41, calculating the target opening adjustment amount of each electrically controlled valve based on the flow deviation of each branch when the flow balance is unstable; Step S42, gradually changing the opening of the electrically controlled valve according to the preset adjustment step size; Step S43, monitoring the change of coolant flow value in real time until the coolant flow value approaches the flow threshold, and determining the dynamic flow distribution result.

5. The method as described in claim 1, characterized in that, Step S5 includes: Step S51, when the flow rate of any branch is lower than the lower limit of its standard range or higher than the upper limit of its standard range, the branch is marked as a temporary abnormal branch; Step S52, the number of times the temporary abnormal branch is marked is counted within multiple consecutive sampling periods; Step S53, when the number of markings exceeds the preset number of confirmations, the branch is determined to be a faulty branch.

6. The method as described in claim 1, characterized in that, Step S6 includes: Step S61, opening the valve of the backup bypass channel that is connected in parallel with the faulty branch; Step S62, monitoring the flow rate of the backup bypass channel; Step S63, confirming the formation of the isolation cooling path after the flow rate of the backup bypass channel reaches the preset bypass flow rate requirement.

7. The method as described in claim 1, characterized in that, Step S7 includes: Step S71, collecting temperature measurement values ​​from multiple temperature sensors in the isolated cooling path; Step S72, performing a weighted average calculation on the multiple temperature measurement values ​​to obtain a fusion temperature value; Step S73, correcting the fusion temperature value by combining a preset ambient temperature correction coefficient; Step S74, determining whether the corrected fusion temperature value is maintained within a safe range and generating a minimum cooling guarantee level.

8. The method as described in claim 1, characterized in that, Step S8 includes: Step S81, when the minimum cooling guarantee level is lower than the cooling threshold, determining the direction of increase or decrease of the coolant pumping rate; Step S82, calculating the adjustment range of the coolant pumping rate based on the degree to which the fusion temperature value deviates from the safe range; Step S83, changing the duty cycle of the drive signal of the standby water pump to achieve continuous adjustment of the coolant pumping rate; Step S84, repeating step S7 until the minimum cooling guarantee level reaches or exceeds the cooling threshold.

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