Battery self-discharge anomaly detection method and device, electronic equipment and storage medium

Abstract

The application provides a battery self-discharge anomaly detection method and device, electronic equipment and a storage medium. The method comprises the following steps: determining whether a target vehicle satisfies a balancing opening condition of a battery management system based on a battery pack internal pressure difference parameter and a battery pack capacity parameter in target vehicle data corresponding to a current period; if not, determining whether the battery of the target vehicle has a self-discharge anomaly by a voltage difference value change trend between a plurality of cell voltages and a highest cell voltage in the battery pack and a voltage change trend of the plurality of cells in the target vehicle data; and if yes, determining a balancing capacity value of each cell in each period, and determining whether the battery of the target vehicle has a self-discharge anomaly based on the consistency of the balancing capacity value of each cell and the change trend of the balancing capacity value of each cell. The self-discharge is detected by the balancing capacity value, and the size and change trend of the self-discharge are quantified, thereby improving the detection efficiency of the cell internal short circuit.

Description

Technical Field

[0001] This application relates to the field of battery testing technology, and in particular to methods, devices, electronic equipment and storage media for detecting abnormal battery self-discharge. Background Technology

[0002] As the energy density of battery cells increases, safety issues in the new energy industry are becoming increasingly prominent. The most significant hazard to electric vehicles / energy storage systems is battery thermal runaway. The root causes of battery thermal runaway are primarily internal and external short circuits within the battery cell. This is mainly characterized by the dissolution of the SEI film on the negative electrode, leading to an exothermic reaction between the negative electrode and its components with the electrolyte. This causes a rapid rise in internal temperature, subsequently resulting in cell fire and explosion. Therefore, preventing battery thermal runaway is both a key focus and a major challenge for the electric vehicle / energy storage industry.

[0003] Currently, under the operating conditions of vehicle / energy storage systems, battery management systems can monitor battery status in real time, and various manufacturers are also monitoring battery voltage differential and its increasing trend. However, current vehicle / energy storage systems have battery balancing functions. When the cell voltage differential reaches a certain threshold, the higher-voltage battery will be discharged to maintain good voltage consistency. This can mask some significant battery self-discharge issues. Therefore, based on the operating conditions of the vehicle / energy storage system, how to detect batteries with abnormal self-discharge through battery data has become a significant technical challenge. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a method, device, electronic device and storage medium for detecting abnormal battery self-discharge. The self-discharge is detected by calculating the equalization capacity value through the equalization function, and the magnitude and trend of self-discharge are quantified. This not only enables the detection of cells with early internal short circuits, but also quantifies the development process of unobservable internal short circuits inside the battery, thereby improving the detection efficiency of internal short circuits in the battery cell.

[0005] This application provides a method for detecting abnormal battery self-discharge, the detection method including:

[0006] Acquire vehicle data for the target vehicle over multiple periods;

[0007] For the current cycle among the multiple cycles, based on the battery pack differential pressure parameter and battery pack capacity parameter in the target vehicle data corresponding to the current cycle, it is determined whether the target vehicle meets the equalization activation conditions of the battery management system.

[0008] If not, then based on the voltage difference trend between the voltage of multiple cells in the battery pack and the highest cell voltage in the target vehicle data, as well as the voltage change trend of multiple cells, it is determined whether the battery of the target vehicle has an abnormal self-discharge situation.

[0009] If so, the balanced capacity value of each cell in each cycle is determined, and based on the consistency of the balanced capacity value of each cell and the changing trend of the balanced capacity value of each cell, it is determined whether the battery of the target vehicle has an abnormal self-discharge.

[0010] In one possible implementation, the following steps are used to determine whether the target vehicle meets the equalization activation conditions of the battery management system:

[0011] If the battery pack capacity parameter is greater than the preset battery pack capacity parameter, and the battery pack internal pressure difference parameter is greater than the preset pressure difference parameter, then the target vehicle meets the equalization activation condition of the battery management system.

[0012] If the battery pack capacity parameter is less than or equal to the preset battery pack capacity parameter and / or the battery pack internal pressure difference parameter is less than or equal to the preset pressure difference parameter, then the target vehicle does not meet the equalization activation condition of the battery management system.

[0013] In one possible implementation, determining whether the battery of the target vehicle is experiencing an abnormal self-discharge based on the voltage difference trend between the voltage of multiple cells in the battery pack and the highest cell voltage, as well as the voltage change trend of multiple cells, in the target vehicle data includes:

[0014] Determine whether the voltage difference between the voltage of multiple cells in the battery pack and the highest cell voltage shows an increasing trend and whether the voltage change trend of the multiple cells shows a decreasing trend within multiple cycles;

[0015] If both are true, then it is determined that the target vehicle's battery is experiencing an abnormal self-discharge.

[0016] If none of the above applies, it is determined that the target vehicle's battery does not exhibit any self-discharge abnormalities.

[0017] In one possible implementation, for each cell in each cycle, the balanced capacity value of each cell in each cycle is determined by the following steps:

[0018] Within the equalization start time and equalization end time, a reference equalization capacity value for each cell is determined based on the product of the equalization current and the equalization time; wherein, the equalization time is the time difference between the acquisition of the voltages of two adjacent cells of that cell.

[0019] The balanced capacity value of the battery cell is determined by summing the multiple reference balanced capacity values ​​within the balanced start time and balanced end time.

[0020] In one possible implementation, determining whether the target vehicle's battery exhibits an abnormal self-discharge based on the consistency of the balanced capacity value of each of the battery cells includes:

[0021] If the balanced capacity values ​​of all cells except the target cell are the same, and the balanced capacity values ​​do not show an increasing trend, then it is determined that the multiple cells of the battery have not experienced any self-discharge abnormalities.

[0022] If the equalization capacity values ​​of all cells except the target cell are the same, and the equalization capacity values ​​of the other cells are greater than the preset equalization capacity value, then it is determined that the target cell has a self-discharge abnormality.

[0023] If the balanced capacity values ​​of all cells other than the target cell are different among the multiple cells, then the balanced capacity values ​​of each cell are ranked in descending order to determine the cells in the battery that have experienced a self-discharge abnormality in multiple consecutive cycles.

[0024] If the balanced capacity values ​​of all cells other than the target cell are different, the difference in balanced capacity between the other cells in two adjacent cycles is determined. The balanced capacity difference of each cell is ranked in descending order, and the cells in the battery whose balanced capacity difference gradually decreases are found to have self-discharge abnormalities.

[0025] In one possible implementation, determining whether the target vehicle's battery exhibits abnormal self-discharge based on the changing trend of the cell's balanced capacity value includes:

[0026] If, within a plurality of the aforementioned cycles, the balanced capacity value of any one of the plurality of battery cells shows a decreasing trend, and the rate of change of the balanced capacity value of that battery cell exceeds a preset rate of change, then it is determined that the battery cell of the battery has a self-discharge abnormality.

[0027] The equal capacity difference between two adjacent cycles of other cells besides the target cell is determined. If any cell continuously exceeds multiple equal capacity differences that are negative, then the cell of the battery is determined to have a self-discharge abnormality.

[0028] This application embodiment also provides a battery self-discharge abnormality detection device, the detection device comprising:

[0029] The acquisition module is used to acquire vehicle data for the target vehicle over multiple periods.

[0030] The equalization judgment module is used to determine, for the current period among the multiple periods, whether the target vehicle meets the equalization activation conditions of the battery management system based on the battery pack internal pressure difference parameter and battery pack capacity parameter in the target vehicle data corresponding to the current period.

[0031] The first detection module is used to determine whether the battery of the target vehicle has an abnormal self-discharge condition based on the voltage difference change trend between the voltage of multiple cells in the battery pack and the highest cell voltage, as well as the voltage change trend of multiple cells in the target vehicle data.

[0032] The second detection module is used to determine the balanced capacity value of each cell in each cycle if the condition is met, and to determine whether the battery of the target vehicle has an abnormal self-discharge condition based on the consistency of the balanced capacity value of each cell and the changing trend of the balanced capacity value of each cell.

[0033] In one possible implementation, the equalization determination module determines whether the target vehicle meets the equalization activation conditions of the battery management system through the following steps:

[0034] If the battery pack capacity parameter is greater than the preset battery pack capacity parameter, and the battery pack internal pressure difference parameter is greater than the preset pressure difference parameter, then the target vehicle meets the equalization activation condition of the battery management system.

[0035] If the battery pack capacity parameter is less than or equal to the preset battery pack capacity parameter and / or the battery pack internal pressure difference parameter is less than or equal to the preset pressure difference parameter, then the target vehicle does not meet the equalization activation condition of the battery management system.

[0036] This application also provides an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the battery self-discharge abnormality detection method described above are performed.

[0037] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the battery self-discharge abnormality detection method described above.

[0038] The battery self-discharge anomaly detection method, apparatus, electronic device, and storage medium provided in this application embodiment include: acquiring vehicle data of a target vehicle for multiple cycles; for the current cycle among the multiple cycles, determining whether the target vehicle meets the equalization activation conditions of the battery management system based on the battery pack internal voltage difference parameter and battery pack capacity parameter in the target vehicle data corresponding to the current cycle; if not, determining whether the target vehicle's battery has a self-discharge anomaly based on the voltage difference change trend between the voltage of multiple cells and the highest cell voltage in the battery pack and the voltage change trend of multiple cells in the target vehicle data; if yes, determining the equalization capacity value of each cell in each cycle, and determining whether the target vehicle's battery has a self-discharge anomaly based on the consistency of the equalization capacity value of each cell and the change trend of the equalization capacity value of each cell. By detecting self-discharge through the equalization capacity value calculated by the equalization function and quantifying the magnitude and change trend of self-discharge, it not only detects cells with early internal short circuits but also quantifies the unobservable internal short circuit development process inside the battery, improving the detection efficiency of internal short circuits in cells.

[0039] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A flowchart illustrating a method for detecting abnormal battery self-discharge provided in an embodiment of this application;

[0042] Figure 2 This is one of the structural schematic diagrams of a battery self-discharge abnormality detection device provided in an embodiment of this application;

[0043] Figure 3 This is a second schematic diagram of a battery self-discharge abnormality detection device provided in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0046] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0047] To enable those skilled in the art to use the content of this application and in conjunction with the specific application scenario of "self-discharge detection of batteries", the following implementation methods are provided. For those skilled in the art, the general principles defined herein can be applied to other embodiments and application scenarios without departing from the spirit and scope of this application.

[0048] The methods, apparatus, electronic devices, or computer-readable storage media described in this application can be applied to any scenario requiring battery self-discharge detection. This application does not limit the specific application scenario. Any scheme using the battery self-discharge abnormality detection method, apparatus, electronic device, and storage medium provided in this application is within the protection scope of this application.

[0049] First, the applicable scenarios for this application will be introduced. This application can be applied to the field of battery testing technology.

[0050] Research has revealed that, currently, under the operating conditions of vehicle / energy storage systems, battery management systems can monitor battery status in real time, and various manufacturers are also monitoring battery voltage differentials and trends of increasing voltage differentials. However, current vehicle / energy storage systems have battery balancing functions. When the cell voltage differential reaches a certain threshold, the higher-voltage battery will be discharged to maintain good voltage consistency. This can mask some significant battery self-discharge issues. Therefore, based on the operating conditions of the vehicle / energy storage system, how to detect batteries with abnormal self-discharge through battery data has become a significant technical challenge.

[0051] Based on this, the embodiments of this application provide a method for detecting abnormal battery self-discharge. The self-discharge is detected by the equalization capacity value calculated by the equalization function, and the magnitude and trend of self-discharge are quantified. This not only enables the detection of cells with early internal short circuits, but also quantifies the development process of unobservable internal short circuits inside the battery, thereby improving the detection efficiency of internal short circuits in the battery cells.

[0052] Please see Figure 1 , Figure 1 This is a flowchart illustrating a method for detecting abnormal battery self-discharge provided in an embodiment of this application. Figure 1 As shown in the embodiments of this application, the detection method includes:

[0053] S101: Acquire vehicle data for the target vehicle over multiple periods.

[0054] In this step, vehicle data for the target vehicle across multiple periods is filtered out from the cloud server.

[0055] Here, a week can be used as a cycle.

[0056] The vehicle data includes other data such as the differential pressure parameters within the battery pack and the battery pack capacity parameters of the target vehicle during that cycle.

[0057] S102: For the current cycle among the multiple cycles, determine whether the target vehicle meets the equalization activation conditions of the battery management system based on the battery pack differential pressure parameter and battery pack capacity parameter in the target vehicle data corresponding to the current cycle.

[0058] In this step, for the current cycle among multiple cycles, the system determines whether the target vehicle meets the equalization activation conditions of the battery management system based on the battery pack differential pressure parameter and battery pack capacity parameter in the target vehicle data corresponding to the current cycle.

[0059] Here, multiple cycles refer to historical cycles, and the current cycle is the cycle with the most recent time point among multiple historical cycles. For example, November 1-7, 2022 is one cycle, November 8-15 is another cycle, and November 16-23 is yet another cycle. Therefore, the cycle corresponding to November 16-23 is the current cycle.

[0060] The conditions for equalization activation include the battery pack capacity parameter being greater than the preset battery pack capacity parameter, and the internal pressure difference parameter of the battery pack being greater than the preset pressure difference parameter.

[0061] The internal pressure difference parameters and battery pack capacity parameters were determined using existing technologies, and will not be elaborated further here.

[0062] In one possible implementation, the following steps are used to determine whether the target vehicle meets the equalization activation conditions of the battery management system:

[0063] A: If the battery pack capacity parameter is greater than the preset battery pack capacity parameter, and the battery pack internal pressure difference parameter is greater than the preset pressure difference parameter, then the target vehicle meets the equalization activation condition of the battery management system.

[0064] Here, if the battery pack capacity parameter is greater than the preset battery pack capacity parameter and the battery pack internal pressure difference parameter is greater than the preset pressure difference parameter, then the target vehicle meets the equalization activation conditions of the battery management system.

[0065] The preset battery pack capacity parameters and preset differential pressure parameters were determined through expert experience.

[0066] B: If the battery pack capacity parameter is less than or equal to the preset battery pack capacity parameter and / or the battery pack internal pressure difference parameter is less than or equal to the preset pressure difference parameter, then the target vehicle does not meet the equalization activation condition of the battery management system.

[0067] Here, if the battery pack capacity parameter is less than or equal to the preset battery pack capacity parameter and / or the battery pack internal pressure difference parameter is less than or equal to the preset pressure difference parameter, the target vehicle does not meet the equalization activation conditions of the battery management system.

[0068] Here, if either the battery pack capacity parameter is less than or equal to the preset battery pack capacity parameter or the battery pack internal pressure difference parameter is less than or equal to the preset pressure difference parameter, the target vehicle does not meet the equalization activation conditions of the battery management system.

[0069] Here, the equalization shutdown condition is determined as follows: when the actual equalization time is determined, the battery management system (BMS) shuts down the equalization function when the actual equalization time is equal to the preset equalization time.

[0070] In a specific embodiment, it is determined whether the target vehicle meets the conditions for BMS passive balancing to be turned on and off. For example, when the battery pack capacity parameter is greater than 30% and the battery pack internal voltage difference parameter is greater than 2mV, the BMS turns on the balancing function, converts the voltage into the SOC and capacity that need to be balanced, and calculates the required balancing time. When the actual balancing time is equal to the preset required balancing time, the BMS turns off the balancing function.

[0071] S103: If not, then based on the voltage difference trend between the voltage of multiple cells in the battery pack and the highest cell voltage in the target vehicle data, and the voltage change trend of multiple cells, it is determined whether the battery of the target vehicle has an abnormal self-discharge situation.

[0072] In this step, if the battery management system's balancing activation conditions are not met, the voltage difference trend between multiple cell voltages and the highest cell voltage within the battery pack in the target vehicle data will be used.

[0073] The voltage change trends of multiple cells can be used to determine whether the target vehicle's battery is experiencing abnormal self-discharge.

[0074] Here, when the voltage difference within the battery pack does not meet the conditions for equalization activation (the voltage difference is small), that is, the BMS has not activated the equalization function for several consecutive cycles, the system comprehensively judges whether an abnormal self-discharge situation has occurred by considering factors such as the maximum voltage difference within the battery pack, the voltage difference change trend between multiple cells and the highest cell voltage within the battery pack, and the voltage ranking change trend.

[0075] 0 In one possible implementation, the battery pack based on the target vehicle data...

[0076] The trend of voltage difference between multiple cell voltages and the highest cell voltage, as well as the voltage change trend of multiple cells, are used to determine whether the target vehicle's battery is experiencing abnormal self-discharge, including:

[0077] (1): Determine the voltage of multiple cells in the battery pack and the highest cell voltage within multiple cycles.

[0078] Whether the voltage difference between the cells shows an increasing trend and whether the voltage change trend of the multiple cells shows a decreasing trend.

[0079] Here, we determine the trend of voltage difference between multiple cells and the highest cell voltage within the battery pack over multiple cycles, and whether the voltage change trend of multiple cells shows a decreasing trend.

[0080] (2): If both are true, then it is determined that the battery of the target vehicle has an abnormal self-discharge.

[0081] If both are true, then it is determined that the target vehicle's battery is experiencing an abnormal self-discharge.

[0082] 0(3): If all are negative, it is determined that the battery of the target vehicle has not experienced any self-discharge abnormality.

[0083] If all of these conditions are not met, then it is determined that the target vehicle's battery has not experienced any self-discharge abnormalities.

[0084] In a specific embodiment, when the pressure difference within the battery pack does not meet the equalization activation condition (the pressure difference is small), i.e., the BMS has not activated the equalization function for several consecutive cycles, then the maximum pressure difference within the battery pack is used to...

[0085] The battery pack's battery self-discharge anomaly is determined by comprehensively considering factors such as the voltage difference trends between multiple cells and the highest-voltage cell, and the voltage ranking trends. If, over multiple cycles, the voltage difference between multiple cells and the highest-voltage cell shows an increasing trend, and the cell ranking shows a decreasing trend, then the target vehicle's battery is confirmed to have a self-discharge anomaly. If, over multiple cycles, the voltage difference between multiple cells and the highest-voltage cell does not show an increasing trend, and the cell ranking shows a decreasing trend, then the target vehicle's battery is confirmed not to have a self-discharge anomaly.

[0086] S104: If so, determine the balanced capacity value of each cell in each cycle, and determine whether the battery of the target vehicle has an abnormal self-discharge based on the consistency of the balanced capacity value of each cell and the changing trend of the balanced capacity value of each cell.

[0087] In this step, if the target vehicle meets the equalization activation conditions of the battery management system, the equalization capacity value of each cell in each cycle is determined. Based on the consistency of the equalization capacity value of each cell and the changing trend of the equalization capacity value of each cell, it is determined whether the battery of the target vehicle has an abnormal self-discharge.

[0088] Here, when the balancing condition is met, that is, the BMS activates the balancing function for multiple consecutive cycles, the balancing capacity value of each cell in each sliding window is calculated based on the conditions for the passive balancing function to be activated and deactivated.

[0089] In one possible implementation, for each cell in each cycle, the balanced capacity value of each cell in each cycle is determined by the following steps:

[0090] a: Within the equalization start time and equalization end time, a reference equalization capacity value for each cell is determined based on the product of the equalization current and the equalization time; wherein, the equalization time is the time difference between the voltages of two adjacent cells of the cell.

[0091] Here, within the equalization start time and equalization end time, the reference equalization capacity value of each cell is determined based on the product of the equalization current and the equalization time.

[0092] The equalization start-up time is the time point at which the voltage difference between each cell and the cell corresponding to the lowest voltage reaches a threshold, and the voltage of each cell is not in the low SOC range.

[0093] The equilibrium end time is the time point corresponding to when the actual equilibrium time equals the preset equilibrium time.

[0094] Here, the equalization time is the time difference between the voltages of two adjacent cells of the battery cell. For example, if the voltage of the first cell of the battery cell is collected at 00:15 and the voltage of the second cell of the battery cell is collected at 00:30, then the time difference is 00:15.

[0095] The equilibrium time is within the equilibrium start time and equilibrium end time.

[0096] The balancing current varies according to the cell voltage, and the balancing current = cell voltage / balancing resistor value.

[0097] b: Sum the multiple reference equalization capacity values ​​within the equalization start time and equalization end time to determine the equalization capacity value of the battery cell.

[0098] Here, the equalization capacity values ​​of multiple reference equalization values ​​within the equalization start time and equalization end time are summed to determine the equalization capacity value of the cell.

[0099] In one possible implementation, determining whether the target vehicle's battery exhibits an abnormal self-discharge based on the consistency of the balanced capacity value of each of the battery cells includes:

[0100] I: If the balanced capacity values ​​of all cells except the target cell are the same and the balanced capacity values ​​do not show an increasing trend, then it is determined that the multiple cells of the battery have not experienced any self-discharge abnormalities.

[0101] Here, if the balanced capacity values ​​of all cells other than the target cell are the same across multiple cycles, and the balanced capacity values ​​of the cells other than the target cell do not show an increasing trend, then it is determined that the multiple cells of the battery have not experienced any self-discharge abnormalities.

[0102] If all cells except target cell A have the same balanced capacity value and there is no increasing trend, then the consistency of multiple cells is good and no abnormal self-discharge occurs.

[0103] II: If the equalization capacity values ​​of all cells other than the target cell are the same, and the equalization capacity values ​​of the other cells are greater than the preset equalization capacity value, then it is determined that the target cell has a self-discharge abnormality.

[0104] Here, if the equalization capacity values ​​of all cells other than the target cell are the same across multiple cycles, and the equalization capacity values ​​of the other cells are greater than the preset equalization capacity value, then it is determined that the target cell has an abnormal self-discharge condition.

[0105] If all cells except target cell A have the same balanced capacity value and show an increasing trend, and the increasing trend exceeds 10mV / day, then target cell A is judged to have abnormal self-discharge.

[0106] III: If the balanced capacity values ​​of all cells other than the target cell are different among the multiple cells, then the balanced capacity values ​​of each cell are ranked in descending order to determine the cells in the battery whose ranking has dropped for multiple consecutive cycles, indicating an abnormal self-discharge situation.

[0107] Here, if the balanced capacity values ​​of all cells other than the target cell are different, the balanced capacity values ​​of each cell are ranked in descending order to identify cells whose ranking has dropped for multiple consecutive cycles and thus indicate abnormal self-discharge.

[0108] If the balanced capacity values ​​of all cells except target cell A are different, they are ranked from largest to smallest based on their balanced capacity values. If cell B's ranking drops for more than 4 consecutive cycles, it indicates that cell B has a trend of increasing self-discharge, and cell B is judged to have abnormal self-discharge.

[0109] IV: If the balanced capacity values ​​of all cells other than the target cell are different among the multiple cells, determine the difference in balanced capacity between the other cells in two adjacent cycles, rank the balanced capacity difference of each cell in descending order, and determine the cells in the battery whose balanced capacity difference gradually decreases that have self-discharge abnormalities.

[0110] Here, if the balanced capacity values ​​of cells other than the target cell are different among multiple cells, the difference in balanced capacity of the cells other than the target cell in two adjacent cycles is determined. The balanced capacity difference of each cell is ranked in descending order, and the cells in the battery with gradually decreasing balanced capacity difference are identified as having abnormal self-discharge.

[0111] If the balanced capacity values ​​of all cells except target cell A are different, the difference in balanced capacity between two adjacent cycles of all cells except target cell A is calculated (the difference between the previous cycle and the next cycle). Based on the difference in balanced capacity, cells are ranked from largest to smallest. If cell B's ranking drops for more than 4 consecutive cycles, it indicates that the cell has a trend of increasing self-discharge, and cell B is judged to have abnormal self-discharge.

[0112] In one possible implementation, determining whether the target vehicle's battery exhibits abnormal self-discharge based on the changing trend of the cell's balanced capacity value includes:

[0113] i: If, within multiple cycles, the balanced capacity value of any one of the multiple cells shows a decreasing trend, and the rate of change of the balanced capacity value of the cell exceeds a preset rate of change, then it is determined that the cell of the battery has a self-discharge abnormality.

[0114] Here, if the balanced capacity value of any one of the multiple cells shows a decreasing trend within multiple cycles, and the rate of change of the balanced capacity value of that cell exceeds the preset rate of change, then it is determined that the cell of the battery has a self-discharge abnormality.

[0115] If the balanced capacity values ​​of all cells except target cell A are different, then the self-discharge abnormal cell detection can be performed based on the change in the balanced capacity of each cell. If the balanced capacity value of a certain cell B is continuously decreasing and the rate of change of the balanced capacity value exceeds 10mV / day, it indicates that the cell has a trend of increasing self-discharge, that is, cell B is judged to be abnormal in self-discharge.

[0116] ii: Determine the equalization capacity difference between two adjacent cycles for all cells other than the target cell. If any cell continuously exceeds multiple equalization capacity differences that are negative, then it is determined that the cell of the battery has a self-discharge abnormality.

[0117] Here, the equal capacity difference between two adjacent cycles of other cells besides the target cell is determined. If any cell continuously exceeds multiple equal capacity differences that are negative, then the cell of the battery is determined to have a self-discharge abnormality.

[0118] Specifically, if the balanced capacity values ​​of all cells except target cell A are different, the difference in balanced capacity between two adjacent windows of all cells except target cell A is calculated (subtracting the previous cycle from the next cycle). If the balanced capacity difference of cell B is negative for more than 4 consecutive cycles, it indicates that the cell has a trend of increasing self-discharge, and cell B is judged to have abnormal self-discharge. Here, the specific number of consecutive cycles is not limited.

[0119] Here, if both the self-discharge anomaly detection methods based on equal capacity consistency and equal capacity change detect a self-discharge anomaly in a certain cell B, then it is determined that the cell has an internal short circuit risk.

[0120] Here, the reason why self-discharge cannot be directly calculated based on the voltage difference is as follows: When the voltage difference is small, the BMS balancing function will not be activated, and the self-discharge anomaly can be directly determined by the voltage difference change. When the voltage difference is large, the BMS will activate the balancing function. At this time, the balancing function will discharge cells whose voltage difference with the minimum voltage exceeds the threshold. This will cause the voltage difference not to increase or even decrease, thus making it impossible to determine the self-discharge anomaly by the voltage difference change.

[0121] This application provides a method for detecting abnormal battery self-discharge. The method includes: acquiring vehicle data for a target vehicle over multiple cycles; for the current cycle, determining whether the target vehicle meets the equalization activation conditions of the battery management system based on the battery pack differential voltage parameter and battery pack capacity parameter in the target vehicle data corresponding to the current cycle; if not, determining whether the target vehicle's battery has experienced abnormal self-discharge based on the voltage difference trend between the voltage of multiple cells and the highest cell voltage in the battery pack, as well as the voltage change trend of multiple cells in the target vehicle data; if yes, determining the equalization capacity value of each cell in each cycle, and determining whether the target vehicle's battery has experienced abnormal self-discharge based on the consistency of the equalization capacity value of each cell and the change trend of the equalization capacity value of each cell. By detecting self-discharge using the equalization capacity value calculated by the equalization function and quantifying the magnitude and trend of self-discharge, this method not only detects cells with early internal short circuits but also quantifies the unobservable internal short circuit development process within the battery, thus improving the detection efficiency of internal short circuits within cells.

[0122] Please see Figure 2 , Figure 3 , Figure 2 This is one of the structural schematic diagrams of a battery self-discharge abnormality detection device provided in an embodiment of this application; Figure 3 This is a second schematic diagram of a battery self-discharge abnormality detection device provided in an embodiment of this application. Figure 2 As shown, the battery self-discharge abnormality detection device 200 includes:

[0123] The acquisition module 210 is used to acquire vehicle data of the target vehicle for multiple periods;

[0124] The equalization judgment module 220 is used to determine, for the current period among the multiple periods, whether the target vehicle meets the equalization activation conditions of the battery management system based on the battery pack internal pressure difference parameter and battery pack capacity parameter in the target vehicle data corresponding to the current period.

[0125] The first detection module 230 is used to determine whether the battery of the target vehicle has an abnormal self-discharge condition based on the voltage difference change trend between the voltage of multiple cells in the battery pack and the highest cell voltage, as well as the voltage change trend of multiple cells in the target vehicle data.

[0126] The second detection module 240 is used to determine the balanced capacity value of each cell in each cycle if the condition is met, and to determine whether the battery of the target vehicle has an abnormal self-discharge condition based on the consistency of the balanced capacity value of each cell and the changing trend of the balanced capacity value of each cell.

[0127] In one possible implementation, the equalization determination module 220 determines whether the target vehicle meets the equalization activation conditions of the battery management system through the following steps:

[0128] If the battery pack capacity parameter is greater than the preset battery pack capacity parameter, and the battery pack internal pressure difference parameter is greater than the preset pressure difference parameter, then the target vehicle meets the equalization activation condition of the battery management system.

[0129] If the battery pack capacity parameter is less than or equal to the preset battery pack capacity parameter and / or the battery pack internal pressure difference parameter is less than or equal to the preset pressure difference parameter, then the target vehicle does not meet the equalization activation condition of the battery management system.

[0130] In one possible implementation, when the first detection module 230 determines whether the battery of the target vehicle is experiencing an abnormal self-discharge based on the voltage difference trend between the voltage of multiple cells and the highest cell voltage in the battery pack, and the voltage change trend of multiple cells in the target vehicle data, the first detection module 230 is specifically used for:

[0131] Determine whether the voltage difference between the voltage of multiple cells in the battery pack and the highest cell voltage shows an increasing trend and whether the voltage change trend of the multiple cells shows a decreasing trend within multiple cycles;

[0132] If both are true, then it is determined that the target vehicle's battery is experiencing an abnormal self-discharge.

[0133] If none of the above applies, it is determined that the target vehicle's battery does not exhibit any self-discharge abnormalities.

[0134] Furthermore, such as Figure 3 As shown, the battery self-discharge abnormality detection device 200 further includes an equalization capacity value determination module 250, which is used for:

[0135] Within the equalization start time and equalization end time, a reference equalization capacity value for each cell is determined based on the product of the equalization current and the equalization time; wherein, the equalization time is the time difference between the acquisition of the voltages of two adjacent cells of that cell.

[0136] The balanced capacity value of the battery cell is determined by summing the multiple reference balanced capacity values ​​within the balanced start time and balanced end time.

[0137] In one possible implementation, when the second detection module 240 determines whether the target vehicle's battery has a self-discharge abnormality based on the consistency of the balanced capacity value of each of the battery cells, the second detection module 240 is specifically used for:

[0138] If the balanced capacity values ​​of all cells except the target cell are the same, and the balanced capacity values ​​do not show an increasing trend, then it is determined that the multiple cells of the battery have not experienced any self-discharge abnormalities.

[0139] If the equalization capacity values ​​of all cells except the target cell are the same, and the equalization capacity values ​​of the other cells are greater than the preset equalization capacity value, then it is determined that the target cell has a self-discharge abnormality.

[0140] If the balanced capacity values ​​of all cells other than the target cell are different among the multiple cells, then the balanced capacity values ​​of each cell are ranked in descending order to determine the cells in the battery that have experienced a self-discharge abnormality in multiple consecutive cycles.

[0141] If the balanced capacity values ​​of all cells other than the target cell are different, the difference in balanced capacity between the other cells in two adjacent cycles is determined. The balanced capacity difference of each cell is ranked in descending order, and the cells in the battery whose balanced capacity difference gradually decreases are found to have self-discharge abnormalities.

[0142] In one possible implementation, when the second detection module 240 determines whether the target vehicle's battery has experienced an abnormal self-discharge based on the changing trend of the balanced capacity value of the battery cell, the second detection module 240 is specifically used for:

[0143] If, within a plurality of the aforementioned cycles, the balanced capacity value of any one of the plurality of battery cells shows a decreasing trend, and the rate of change of the balanced capacity value of that battery cell exceeds a preset rate of change, then it is determined that the battery cell of the battery has a self-discharge abnormality.

[0144] The equal capacity difference between two adjacent cycles of other cells besides the target cell is determined. If any cell continuously exceeds multiple equal capacity differences that are negative, then the cell of the battery is determined to have a self-discharge abnormality.

[0145] This application provides a battery self-discharge abnormality detection device, comprising: an acquisition module for acquiring vehicle data of a target vehicle for multiple cycles; an equalization judgment module for determining, for the current cycle among the multiple cycles, whether the target vehicle meets the equalization activation conditions of the battery management system based on the battery pack differential voltage parameter and battery pack capacity parameter in the target vehicle data corresponding to the current cycle; a first detection module for determining, if not, whether the target vehicle's battery has a self-discharge abnormality based on the voltage difference change trend between the voltage of multiple cells and the highest cell voltage in the battery pack and the voltage change trend of multiple cells in the target vehicle data; and a second detection module for determining, if yes, the equalization capacity value of each cell in each cycle, and determining whether the target vehicle's battery has a self-discharge abnormality based on the consistency of the equalization capacity value of each cell and the change trend of the equalization capacity value of each cell. By using the equalization capacity value calculated by the equalization function to detect self-discharge and quantify the magnitude and trend of self-discharge, it is possible to not only detect cells with early internal short circuits, but also quantify the development process of unobservable internal short circuits inside the battery, thereby improving the detection efficiency of internal short circuits in cells.

[0146] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device 400 includes a processor 410, a memory 420, and a bus 430.

[0147] The memory 420 stores machine-readable instructions executable by the processor 410. When the electronic device 400 is running, the processor 410 communicates with the memory 420 via the bus 430. When the machine-readable instructions are executed by the processor 410, they can perform the operations described above. Figure 1 The steps for detecting abnormal battery self-discharge in the method embodiment shown are explained in detail in the method embodiment, and will not be repeated here.

[0148] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 The steps of the battery self-discharge abnormality detection method in the method embodiment shown are described in detail in the method embodiment, and will not be repeated here.

[0149] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0150] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0151] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0152] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0153] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0154] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method of detecting abnormal self-discharge of a battery, characterized by, The detection method comprises: obtaining vehicle data of a target vehicle in multiple periods; for a current period in the multiple periods, determining whether the target vehicle satisfies a balancing opening condition of a battery management system based on a battery pack internal pressure difference parameter and a battery pack capacity parameter in the target vehicle data corresponding to the current period; if not, determining whether the battery of the target vehicle has a self-discharge abnormal condition based on a voltage difference value change trend between multiple cell voltages and a highest cell voltage in the target vehicle data and a voltage change trend of the multiple cells; if yes, determining a balancing capacity value of each cell in each period, and determining whether the battery of the target vehicle has a self-discharge abnormal condition based on consistency of the balancing capacity value of each cell and a change trend of the balancing capacity value of each cell; the determination of whether the battery of the target vehicle has a self-discharge abnormal condition based on the consistency of the balancing capacity value of each cell comprises: if the balancing capacity values of the cells other than a target cell in the multiple cells are all the same, and the balancing capacity values do not show an increasing trend, it is determined that the multiple cells of the battery do not have a self-discharge abnormal condition; if the balancing capacity values of the cells other than the target cell in the multiple cells are all the same, and the balancing capacity values of the other cells are greater than a preset balancing capacity value, it is determined that the target cell has a self-discharge abnormal condition; if the balancing capacity values of the cells other than the target cell in the multiple cells are all different, ranking the balancing capacity values of each cell in descending order, and determining that the cells in the battery that have a ranking drop in consecutive multiple periods have a self-discharge abnormal condition; if the balancing capacity values of the cells other than the target cell in the multiple cells are all different, determining a balancing capacity difference value of the other cells other than the target cell in adjacent two periods, ranking the balancing capacity difference values of each cell in descending order, and determining that the cells in the battery whose balancing capacity difference values gradually decrease have a self-discharge abnormal condition.

2. The detection method according to claim 1, characterized in that, The determination of whether the target vehicle satisfies the balancing opening condition of the battery management system comprises: if the battery pack capacity parameter is greater than a preset battery pack capacity parameter, and the battery pack internal pressure difference parameter is greater than a preset pressure difference parameter, the target vehicle satisfies the balancing opening condition of the battery management system; if the battery pack capacity parameter is less than or equal to the preset battery pack capacity parameter and / or the battery pack internal pressure difference parameter is less than or equal to the preset pressure difference parameter, the target vehicle does not satisfy the balancing opening condition of the battery management system.

3. The method of claim 1, wherein The determination of whether the battery of the target vehicle has a self-discharge abnormal condition based on the voltage difference value change trend between the multiple cell voltages and the highest cell voltage in the target vehicle data and the voltage change trend of the multiple cells comprises: determining whether a voltage difference change trend between the plurality of cell voltages and the highest cell voltage in the battery pack and a voltage change trend of the plurality of cells in each of the plurality of periods is increasing; if both are, determining that the battery of the target vehicle has a self-discharge abnormality; if both are not, determining that the battery of the target vehicle does not have a self-discharge abnormality.

4. The method of claim 1, wherein, For each of the cells in each of the periods, the equalization capacity value of each cell in each period is determined by the following steps: determining a reference equalization capacity value of each cell based on the product of the equalization current and the equalization time within the equalization start time and the equalization end time, wherein the equalization time is the time difference between the adjacent two cell voltages of the cell; summing the plurality of reference equalization capacity values within the equalization start time and the equalization end time to determine the equalization capacity value of the cell.

5. The method of claim 1, wherein The determination of whether the battery of the target vehicle has a self-discharge abnormality based on the change trend of the equalization capacity value of the cell includes: if the equalization capacity value of any one of the plurality of cells in the plurality of periods presents a decreasing trend, and the change rate of the equalization capacity value of the cell exceeds a preset change rate, it is determined that the cell of the battery has a self-discharge abnormality; determining the equalization capacity difference value of the other cells except the target cell in the adjacent two periods, if any one of the cells continuously exceeds a plurality of the equalization capacity difference values, it is determined that the cell of the battery has a self-discharge abnormality.

6. A battery self-discharge abnormality detection device characterized by comprising: The detection device includes: an acquisition module configured to acquire vehicle data of a target vehicle in a plurality of periods; an equalization judgment module configured to, for a current period in the plurality of periods, determine whether the target vehicle satisfies an equalization start condition of a battery management system based on a pressure difference parameter in the battery pack and a battery pack capacity parameter in the target vehicle data corresponding to the current period; a first detection module configured to, if not, determine whether the battery of the target vehicle has a self-discharge abnormality based on a voltage difference change trend between a plurality of cell voltages in the battery pack and a highest cell voltage and a voltage change trend of the plurality of cells in the target vehicle data; a second detection module configured to, if yes, determine an equalization capacity value of each cell in each period, and determine whether the battery of the target vehicle has a self-discharge abnormality based on consistency of the equalization capacity value of each cell and a change trend of the equalization capacity value of each cell; the second detection module is configured to determine whether the battery of the target vehicle has a self-discharge abnormality based on the consistency of the equalization capacity value of each cell: if the equalization capacity values of the other cells except the target cell in the plurality of cells are all the same, and the equalization capacity values do not present an increasing trend, it is determined that the plurality of cells of the battery do not have a self-discharge abnormality. If the equalization capacity values of the other cells except the target cell among the plurality of cells are all the same, and the equalization capacity value of the other cells is greater than a preset equalization capacity value, it is determined that the target cell has a self-discharge abnormality; If the equalization capacity values of the other cells except the target cell among the plurality of cells are all different, the equalization capacity values of each of the cells are ranked in descending order, and it is determined that the cells in the battery whose rankings decrease continuously in a plurality of cycles have a self-discharge abnormality; If the equalization capacity values of the other cells except the target cell among the plurality of cells are all different, the equalization capacity difference values of each of the cells are ranked in descending order, and it is determined that the cells in the battery whose equalization capacity difference values gradually decrease have a self-discharge abnormality.

7. The detection device of claim 6, wherein, The equalization judgment module determines whether the target vehicle satisfies the equalization start condition of the battery management system by the following steps: If the battery pack capacity parameter is greater than a preset battery pack capacity parameter, and the battery pack internal pressure difference parameter is greater than a preset pressure difference parameter, the target vehicle satisfies the equalization start condition of the battery management system; If the battery pack capacity parameter is less than or equal to the preset battery pack capacity parameter and / or the battery pack internal pressure difference parameter is less than or equal to the preset pressure difference parameter, the target vehicle does not satisfy the equalization start condition of the battery management system.

8. An electronic device, comprising: The method comprises: A processor, a memory and a bus, the memory stores machine readable instructions executable by the processor, when the electronic device is running, the processor and the memory communicate through the bus, the machine readable instructions are executed by the processor to perform the steps of the battery self-discharge abnormality detection method as claimed in any one of claims 1 to 5.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, the computer program is executed by the processor to perform the steps of the battery self-discharge abnormality detection method as claimed in any one of claims 1 to 5.

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