An abnormal battery cell identification method, device, medium and electronic equipment

Abstract

The application discloses an abnormal battery cell identification method, device, medium and electronic equipment, and is applied to a lithium iron phosphate battery. The lithium iron phosphate battery comprises a plurality of battery cells. The method comprises the following steps: acquiring the battery residual capacity of the lithium iron phosphate battery and the battery cell voltage of each battery cell; determining the current area where the lithium iron phosphate battery is located according to the battery residual capacity; if the current area is a platform area, the following steps are used to determine whether the battery cell is at risk of being abnormal: determining a reference voltage according to the battery cell voltage of each battery cell, wherein the reference voltage is the voltage when the battery cell is normally working; for each battery cell, determining the voltage difference between the battery cell voltage and the reference voltage; if the absolute value of the voltage difference is greater than or equal to a voltage difference threshold value, the battery cell is at risk of being abnormal, the voltage difference threshold value is a positive value, and the voltage difference threshold value is the upper limit value of the voltage difference when the battery cell is normally working. The application can improve the identification accuracy of abnormal battery cells.

Description

Technical Field

[0001] This application relates to the field of lithium iron phosphate battery cell technology, and in particular, to a method, apparatus, medium, and electronic device for identifying abnormal battery cells. Background Technology

[0002] When testing cell consistency, the battery pack is usually charged and discharged to obtain the rate of change of volume per unit voltage interval. The difference between cells is then assessed based on the rate of change of volume per unit voltage interval. However, for lithium iron phosphate batteries, the open circuit voltage (OCV) curve is relatively flat, especially in the plateau region, where the voltage change is small. Therefore, it is difficult to accurately assess the difference between cells using the rate of change of volume per unit voltage interval, resulting in low accuracy in identifying abnormal cells. Summary of the Invention

[0003] Embodiments of this application provide a method, apparatus, medium, and electronic device for identifying abnormal battery cells, which solves the technical problem that it is difficult to accurately assess the differences between individual cells of a lithium iron phosphate battery by measuring the rate of change of internal volume per unit voltage interval.

[0004] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0005] According to a first aspect of this application, an abnormal battery cell identification method is provided, applied to a lithium iron phosphate battery, the lithium iron phosphate battery comprising multiple battery cells, the method comprising:

[0006] Obtain the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell;

[0007] Based on the remaining capacity of the battery, determine the current region where the lithium iron phosphate battery is located. If the current region is a plateau region, determine whether the cell has any abnormal risks through the following steps:

[0008] A reference voltage is determined based on the cell voltage of each of the aforementioned cells, wherein the reference voltage is the voltage at which the cell operates normally.

[0009] For each of the battery cells, the voltage difference between the cell voltage and the reference voltage is determined. If the absolute value of the voltage difference is greater than or equal to the voltage difference threshold, the battery cell has an abnormal risk. The voltage difference threshold is a positive value and is the upper limit of the voltage difference when the battery cell is working normally.

[0010] In some embodiments of this application, based on the foregoing scheme, after determining the current region where the lithium iron phosphate battery is located according to the remaining battery capacity, if the current region is a non-platform region, the method further includes:

[0011] For each battery cell, the remaining capacity of the battery cell is obtained based on the cell voltage.

[0012] A reference remaining capacity is determined based on the remaining capacity of each of the battery cells, and the reference remaining capacity is the remaining capacity of the battery cell when it is working normally;

[0013] For each cell, the capacity difference between the cell's remaining capacity and the reference remaining capacity is determined. If the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, the cell has an abnormal risk. The capacity difference threshold is a positive value and is the upper limit of the capacity difference when the cell is working normally.

[0014] In some embodiments of this application, based on the foregoing scheme, obtaining the remaining capacity of the battery cell according to the cell voltage includes:

[0015] Based on the cell voltage, the remaining cell capacity is obtained from a preset relationship table, which shows the correspondence between voltage and remaining capacity.

[0016] In some embodiments of this application, based on the foregoing scheme, determining the reference remaining capacity according to the remaining capacity of each of the battery cells includes:

[0017] The first reference value of the remaining capacity of each of the battery cells is used as the reference remaining capacity, wherein the first reference value includes one of the median, mode and mean.

[0018] The step of determining the reference voltage based on the cell voltage of each of the battery cells includes:

[0019] The second reference value of the cell voltage of each of the cells is used as the reference cell voltage, and the second reference value includes one of the median, mode and mean.

[0020] In some embodiments of this application, based on the foregoing scheme, before obtaining the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell, the method further includes:

[0021] Acquire multiple sets of vehicle data, each set of vehicle data including vehicle current, vehicle power-off duration, battery cell voltage, and battery cell temperature;

[0022] For each set of vehicle data, if the cell voltage of the battery cell in the vehicle data is within a preset voltage range, the cell temperature of the battery cell is within a preset temperature range, the vehicle current is within a preset current range, and the vehicle power-off time is greater than a preset time, then the step of obtaining the remaining capacity of the lithium iron phosphate battery and the cell voltage of each battery cell is executed.

[0023] In some embodiments of this application, based on the foregoing scheme, obtaining the remaining capacity of the lithium iron phosphate battery includes:

[0024] Obtain the remaining capacity of each of the battery cells;

[0025] Among the remaining capacity of each of the battery cells, the maximum value is taken as the first remaining capacity, and the minimum value is taken as the second remaining capacity.

[0026] Determine the first remaining capacity difference between the first remaining capacity and the second remaining capacity;

[0027] Determine a second remaining capacity difference between the maximum capacity of the lithium iron phosphate battery and the first remaining capacity difference;

[0028] The ratio between the second remaining capacity and the difference between the second remaining capacity is taken as the remaining capacity of the battery.

[0029] In some embodiments of this application, based on the foregoing scheme, the method further includes:

[0030] For each battery cell, if the number of abnormal risks of the battery cell is greater than or equal to a preset number within the target time period, the battery cell is determined to be an abnormal battery cell.

[0031] According to a second aspect of this application, an abnormal battery cell identification device is provided, applied to a lithium iron phosphate battery, the lithium iron phosphate battery comprising a plurality of battery cells, the device comprising:

[0032] The first acquisition unit acquires the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell.

[0033] The first determining unit determines the current region where the lithium iron phosphate battery is located based on the remaining capacity of the battery. If the current region is a platform region, the configuration is as follows:

[0034] The second determining unit determines a reference voltage based on the cell voltage of each of the battery cells, wherein the reference voltage is the voltage of the battery cell when it is operating normally.

[0035] The third determining unit determines the voltage difference between the cell voltage and the reference voltage for each cell. If the absolute value of the voltage difference is greater than or equal to the voltage difference threshold, the cell has an abnormal risk. The voltage difference threshold is a positive value and is the upper limit of the voltage difference when the cell is working normally.

[0036] In some embodiments of this application, based on the foregoing scheme, a fourth determining unit is further included. This fourth determining unit is configured to, after determining the current region where the lithium iron phosphate battery is located based on the remaining battery capacity, if the current region is a non-platform region, then:

[0037] The second acquisition unit acquires the remaining capacity of each battery cell based on its cell voltage.

[0038] The fifth determining unit determines a reference remaining capacity based on the remaining capacity of each of the battery cells, wherein the reference remaining capacity is the remaining capacity of the battery cell when it is working normally;

[0039] The sixth determining unit determines, for each cell, the capacity difference between the cell's remaining capacity and the reference remaining capacity. If the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, then the cell has an abnormal risk. The capacity difference threshold is a positive value and is the upper limit of the capacity difference when the cell is working normally.

[0040] In some embodiments of this application, based on the foregoing scheme, the second acquisition unit is configured as follows:

[0041] The third acquisition unit obtains the remaining capacity of the battery cell from a preset relationship table based on the battery cell voltage. The preset relationship table is a correspondence between voltage and remaining capacity.

[0042] In some embodiments of this application, based on the foregoing scheme, the fifth determining unit is configured as follows:

[0043] The first unit uses a first reference value of the remaining capacity of each of the battery cells as the reference remaining capacity, wherein the first reference value includes one of the median, mode and mean.

[0044] The second determining unit is configured as follows:

[0045] The second unit uses a second reference value of the cell voltage of each of the cells as the reference cell voltage, wherein the second reference value includes one of the median, mode and mean.

[0046] In some embodiments of this application, based on the foregoing scheme, a first execution unit is further included. The first execution unit is configured to: Before obtaining the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell, the first execution unit is configured to:

[0047] The fourth acquisition unit acquires multiple sets of vehicle data, each set of vehicle data including vehicle current, vehicle power-off duration, battery cell voltage, and battery cell temperature;

[0048] The second execution unit, for each set of vehicle data, performs the steps of obtaining the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell when the cell voltage of the battery cell in the vehicle data is within a preset voltage range, the cell temperature of the battery cell is within a preset temperature range, the vehicle current is within a preset current range, and the vehicle power-off time is greater than a preset time.

[0049] In some embodiments of this application, based on the foregoing scheme, the first acquisition unit is configured as follows:

[0050] The fifth acquisition unit acquires the remaining capacity of each of the battery cells;

[0051] The third unit, among the remaining capacity of each of the battery cells, takes the maximum value as the first remaining capacity and the minimum value as the second remaining capacity.

[0052] The seventh determining unit determines the first remaining capacity difference between the first remaining capacity and the second remaining capacity;

[0053] The eighth determining unit determines a second remaining capacity difference between the maximum capacity of the lithium iron phosphate battery and the first remaining capacity difference.

[0054] The fourth unit uses the ratio between the second remaining capacity and the difference between the second remaining capacity as the remaining capacity of the battery.

[0055] In some embodiments of this application, based on the foregoing solution, the apparatus further includes:

[0056] The ninth determining unit determines the battery cell as an abnormal battery cell if, within a target time period, the number of abnormal risks of the battery cell is greater than or equal to a preset number.

[0057] According to a third aspect of this application, a computer-readable storage medium is provided having a computer program stored thereon, characterized in that the computer program includes executable instructions that, when executed by a processor, implement the method described in any embodiment of the first aspect of this application.

[0058] According to a fourth aspect of this application, an electronic device is provided, comprising: one or more processors; and a memory for storing executable instructions of the processors, which, when executed by the one or more processors, cause the one or more processors to implement the method described in any embodiment of the first aspect of this application.

[0059] The beneficial effects of this application are as follows:

[0060] For lithium iron phosphate batteries, when the remaining capacity of the battery is in the plateau region, the voltage will change when the cell is abnormal. Although the change is small, it will still occur. If the voltage difference exceeds the voltage difference threshold, the abnormal risk of the cell can be identified in time, and the identification accuracy is high.

[0061] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0062] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0063] Figure 1 A flowchart of an abnormal battery cell identification method according to an embodiment of this application is shown;

[0064] Figure 2 A block diagram of an abnormal battery cell identification device according to an embodiment of this application is shown;

[0065] Figure 3 A schematic diagram of a computer-readable storage medium in an embodiment of this application is shown;

[0066] Figure 4 A schematic diagram of the system structure of an electronic device in an embodiment of this application is shown. Detailed Implementation

[0067] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0068] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0069] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0070] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0071] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0072] Figure 1 This application illustrates an abnormal cell identification method, applied to a lithium iron phosphate battery. The lithium iron phosphate battery includes multiple cells, each of which can be a single cell. The method includes at least steps S1 and S2, which are described in detail below:

[0073] In step S1, the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell are obtained. The remaining capacity is the battery's SOC (State of Charge), and the cell voltage is the voltage of the cell.

[0074] In some implementations, the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell are obtained through a battery management system.

[0075] In step S2, the current region where the lithium iron phosphate battery is located is determined based on the remaining battery capacity. If the current region is a plateau region, the following steps are used to determine whether the cell has any abnormal risk: a reference voltage is determined based on the cell voltage of each cell, where the reference voltage is the voltage when the cell is operating normally; for each cell, the voltage difference between the cell voltage and the reference voltage is determined. If the absolute value of the voltage difference is greater than or equal to a voltage difference threshold, the cell has an abnormal risk. The voltage difference threshold is a positive value and is the upper limit of the voltage difference when the cell is operating normally. On the one hand, this can be understood as: if the voltage difference is greater than or equal to the voltage difference threshold, or less than or equal to the opposite of the voltage difference threshold, the cell has an abnormal risk; on the other hand, this can be understood as: screening |Δvol ij Cells with |>λ_vol are cells with potential abnormal risks, △vol ij Let λ_vol be the voltage difference, and λ_vol be the parameter for cell anomalies, i.e., the voltage difference threshold. Steps S1 to S2 can be processed in the cloud, thereby improving processing efficiency.

[0076] In existing technologies, when lithium iron phosphate batteries are in a plateau region, cell differences are assessed by evaluating the rate of change of capacity per unit voltage interval. This means the cell difference is assessed based on the ratio of capacity change to voltage change (per unit voltage interval). Abnormal cells exhibit larger voltage changes compared to normal cells, but the order of magnitude of capacity change is much larger. This makes the rate of change of capacity per unit voltage interval for abnormal cells not significantly different from that of normal cells, thus hindering the identification of abnormal cells. In this application, the lithium iron phosphate battery is in a plateau region, and... By comparing the voltage difference with the voltage difference threshold, it is determined whether the battery cell has any abnormal risk. Abnormal battery cells exhibit larger voltage changes compared to normal cells. Although the difference may not be significant, by setting an appropriate voltage difference threshold, the voltage difference between abnormal and normal cells can be distinguished. For example, the voltage difference of a normal battery cell is below 100mV, while the voltage difference of an abnormal battery cell is above 100mV. Setting the voltage difference threshold to 100mV can clearly distinguish between abnormal and normal cells, thus accurately identifying abnormal cells and determining those with abnormal risks. The rate of change of capacity per unit voltage interval can be obtained using the dQ / dV curve (differential capacity curve).

[0077] It should be noted that the plateau region refers to a relatively flat and stable area in the charge-discharge curve of the lithium iron phosphate battery. Within the plateau region, the voltage of the lithium iron phosphate battery decreases or increases at a relatively slow rate, which is equivalent to the lithium iron phosphate battery being in a relatively stable state.

[0078] In some implementations, the differential pressure threshold is 100mV to 300mV.

[0079] In some embodiments, the lithium iron phosphate battery includes multiple cell modules, each cell module including multiple cells distributed along a first direction and two probes for detecting cell temperature. One probe detects the temperature of a first cell, and the other probe detects the temperature of a second cell, the first cell and the second cell being located at the head and tail of the plurality of cells, respectively.

[0080] In some implementations, for each cell module, if one probe detects a temperature of T1 and another probe detects a temperature of T2, then the temperature of the cell is T1 or T2 or (T1 + T2) / 2.

[0081] In some implementations, if the absolute value of the voltage difference is less than the voltage difference threshold, then the cell does not have any abnormal risk; that is, if the voltage difference is greater than the negative of the voltage difference threshold but less than the voltage difference threshold, then the cell does not have any abnormal risk.

[0082] In some implementations, after determining the current region where the lithium iron phosphate battery is located based on the remaining battery capacity, if the current region is a non-platform region, the method further includes: for each cell, obtaining the remaining cell capacity of the cell based on the cell voltage; determining a reference remaining capacity based on the remaining cell capacity of each cell, the reference remaining capacity being the remaining capacity when the cell is operating normally; for each cell, determining the capacity difference between the remaining cell capacity of the cell and the reference remaining capacity, and if the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, then the cell has an abnormal risk, the capacity difference threshold being a positive value, the upper limit of the capacity difference when the cell is operating normally. On one hand, this can be understood as if the capacity difference is greater than or equal to the capacity difference threshold or less than or equal to the opposite of the capacity difference threshold, then the cell has an abnormal risk; on the other hand, it can be understood as screening |ΔSOC ij The cells with |>λ_soc are cells with potential abnormal risks, △SOC ij The capacity difference is represented by λ_soc, which is a parameter indicating cell anomaly, i.e., the capacity difference threshold. The remaining capacity of the cell is the cell's true SOC, which can be denoted as SOC_Real.

[0083] It should be noted that the non-plateau region refers to a region in the charge-discharge curve of the lithium iron phosphate battery where the voltage changes significantly. Within the non-plateau region, the voltage of the lithium iron phosphate battery decreases or increases more rapidly. In other words, the voltage decreases or increases more rapidly than when the lithium iron phosphate battery is in the plateau region.

[0084] In this application, when the lithium iron phosphate battery is in the non-platform region, even normal cells will have a large voltage difference. If the voltage difference is used for evaluation, normal cells are easily evaluated as abnormal cells, resulting in misjudgment. Abnormal cells will have a large capacity difference, while normal cells will not have a large capacity difference. If the capacity difference is used to evaluate whether the cell has an abnormal risk, misjudgment is less likely to occur, and the evaluation accuracy is high.

[0085] In some embodiments, determining the current region of the lithium iron phosphate battery based on its remaining capacity includes: if the remaining battery capacity is 30%-95%, the current region is a plateau region; if the remaining battery capacity is 0-30%, the current region is a non-plateau region. That is, the remaining battery capacity determines whether the lithium iron phosphate battery is currently in a plateau region or a non-plateau region. When the lithium iron phosphate battery is in a plateau region, 30% ≤ SOC. internal ≤95%, when the lithium iron phosphate battery is in the non-plateau region, 0≤SOC internal <30%, SOC internal This refers to the remaining battery capacity or internal SOC.

[0086] In some embodiments, obtaining the remaining capacity of the battery cell based on its cell voltage includes: obtaining the remaining capacity of the battery cell from a preset relationship table based on its cell voltage, wherein the preset relationship table is a correspondence between voltage and remaining capacity. The preset relationship table can be an OCV-SOC table for a battery pack, where the OCV-SOC table is a table showing the relationship between open-circuit voltage (OCV) and remaining capacity (SOC).

[0087] For example, based on the cell voltage U and the battery pack's OCV-SOC table, the true SOC, i.e., the remaining cell capacity, is obtained by looking up the table, i.e., SOC_Real. ij ,i∈[1,m],j∈[1,n],i is the i-th data set,m is the number of data sets (m),j is the j-th cell,n is the number of cells in the lithium iron phosphate battery (n cells),SOC_Real ij Let be the actual SOC of the j-th cell in the i-th data set.

[0088] In some embodiments, determining the reference remaining capacity based on the remaining capacity of each of the battery cells includes: using a first reference value of the remaining capacity of each of the battery cells as the reference remaining capacity, wherein the first reference value includes one of the median, mode, and mean; determining the reference voltage based on the battery voltage of each of the battery cells includes: using a second reference value of the battery voltage of each of the battery cells as the reference battery voltage, wherein the second reference value includes one of the median, mode, and mean.

[0089] In some implementations, the first reference value is the median, and the second reference value is the median. When there are tiers in the cell voltages of the individual cells, the median is more representative. For example, if the lithium iron phosphate battery comprises 100 cells, with 50 cells having a cell voltage of 3.4-3.5V and the remaining 50 cells having a cell voltage of 3.2-3.3V, the average value would be 3.35V, which clearly does not represent the true situation of the cell voltages. The median is more representative. Similarly, if the remaining capacity of the 50 cells is 60%-61% and the remaining cell voltage is 58%-59%, the average value would be 59.5%, which clearly does not represent the true situation of the remaining cell capacity. The median is more representative.

[0090] In some implementations, when the first reference value includes the median, the first reference value is determined by the following formula:

[0091] SOC_Median i = median(SOC_Real i1 SOC_Real i2 ...,SOC_Real ij ), i∈[1,m],j∈[1,n], SOC_Median i Let `median` be the median of the true State of Charge (SOC) of each cell in the i-th data set, where `median` is a function for calculating the median, `i` represents the i-th data set, `m` represents the number of data sets (m), `j` represents the j-th cell, and `n` represents the number of cells in the lithium iron phosphate battery. `SOC_Real` represents the median of the true State of Charge (SOC) of each cell in the i-th data set. ij Let be the actual SOC of the j-th cell in the i-th data set.

[0092] In some implementations, when the first reference value includes the median, the capacity difference is determined by the following formula: △SOC ij =SOC_Real ij -SOC_Median i , i∈[1,m], j∈[1,n], △SOC ij SOC_Real represents the capacity difference of the j-th cell in the i-th data set, where i is the i-th data set, m represents the number of data sets (m), j is the j-th cell, and n represents the number of cells in the lithium iron phosphate battery. ij Let SOC_Median be the true SOC of the j-th cell in the i-th data set. i Let be the median of the actual SOC of each cell in the i-th data set.

[0093] In some implementations, when the second reference value includes the median, the second reference value is determined by the following formula: vol_Mediani = median(vol i1 , vol i2 ..., vol ij ), i∈[1,m],j∈[1,n], vol_Median i Let be the median of the cell voltage of each cell in the i-th data set, where median is a function for calculating the median, i is the i-th data set, m represents the number of data sets (m), j is the j-th cell, n represents the number of cells in the lithium iron phosphate battery, and vol ij The cell voltage of the j-th cell in the i-th data set.

[0094] In some implementations, when the second reference value includes the median, the voltage difference is determined by the following formula: Δvol ij =vol ij -vol_Median i , i∈[1,m], j∈[1,n], △vol ij Let be the voltage difference of the j-th cell in the i-th data set, where i is the i-th data set, m represents the number of data sets (m), j is the j-th cell, n represents the number of cells in the lithium iron phosphate battery, and vol ij The cell voltage of the j-th cell in the i-th data set, vol_Median i The median of the cell voltage of each cell in the i-th data set.

[0095] In some embodiments, before obtaining the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell, the method further includes: acquiring multiple sets of vehicle data, each set of vehicle data including vehicle current, vehicle power-off duration, cell voltage, and cell temperature; for each set of vehicle data, if the cell voltage of the cell is within a preset voltage range, the cell temperature is within a preset temperature range, the vehicle current is within a preset current range, and the vehicle power-off duration is greater than a preset duration, then the step of obtaining the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell is performed. Each set of vehicle data can be each frame of data uploaded by the vehicle to the cloud. The multiple sets of vehicle data can be the national standard historical data of the vehicle within one week, and the cell temperature can be the temperature detected by the probe or the probe temperature.

[0096] It should be noted that if the battery cell voltage and temperature of the vehicle data are within a preset voltage range and a preset temperature range, the vehicle data is considered normal. If the vehicle data is outside the preset voltage range or the battery cell temperature is outside the preset temperature range, the vehicle data is considered abnormal. Therefore, filtering abnormal data can increase data reliability. If the vehicle current is within a preset current range and the vehicle power-off time is greater than a preset time, the vehicle data is considered stationary data. If the vehicle current is outside the preset current range or the vehicle power-off time is not greater than the preset time, the vehicle data is considered non-stationary data. Therefore, filtering non-stationary data further improves data reliability.

[0097] In some implementations, the preset voltage range is 0-5V, the preset temperature range is -40 to 125°C, the preset current range is -1 to 1A, and the preset duration is 1 hour or 2 hours.

[0098] In some embodiments, obtaining the remaining capacity of the lithium iron phosphate battery includes: obtaining the remaining capacity of each cell; among the remaining capacities of each cell, taking the maximum value as a first remaining capacity and the minimum value as a second remaining capacity; determining a first remaining capacity difference between the first remaining capacity and the second remaining capacity; determining a second remaining capacity difference between the maximum capacity of the lithium iron phosphate battery and the first remaining capacity difference; and taking the ratio between the second remaining capacity and the second remaining capacity difference as the remaining battery capacity. The remaining battery capacity can be understood as the internal state of charge (SOC) of the lithium iron phosphate battery.

[0099] In some implementations, the first remaining capacity is determined by the following formula:

[0100] SOC_real max = Max(SOC_Real i1 SOC_Real i2 ...,SOC_Real ij ), i∈[1,m],j∈[1,n], SOC_real max SOC_Real is the first remaining capacity, and Max is a function to calculate the maximum value. ij Let represent the true SOC of the j-th cell in the i-th data set, where i is the i-th data set, m represents a set of m data sets, j is the j-th cell, and n represents a lithium iron phosphate battery with n cells.

[0101] In some implementations, the second remaining capacity is determined by the following formula:

[0102] SOC_real min = Min(SOC_Real i1 SOC_Real i2 ...,SOC_Real ij ), i∈[1,m],j∈[1,n], SOC_real min The second remaining capacity is defined as SOC_Real, where Min is a function to calculate the minimum value. ij Let represent the true SOC of the j-th cell in the i-th data set, where i is the i-th data set, m represents a set of m data sets, j is the j-th cell, and n represents a lithium iron phosphate battery with n cells.

[0103] In some implementations, the remaining battery capacity is determined by the following formula:

[0104] SOC internal =Maximum capacity of the lithium iron phosphate battery × SOC_real min / [The maximum capacity of the lithium iron phosphate battery - (SOC_real) max -SOC_real min SOC internal SOC_real represents the remaining battery power. min For the second remaining capacity, SOC_real max This represents the first remaining capacity.

[0105] In some embodiments, the method further includes: for each battery cell, if the number of abnormal risks of the battery cell is greater than or equal to a preset number within a target time period, the battery cell is determined to be an abnormal battery cell. The preset number is greater than or equal to 1.

[0106] In some implementations, the multiple sets of vehicle data can be historical national standard data of the vehicle within one week. The method further includes: within one week, for each time period, if the number of abnormal risks of the battery cell is greater than or equal to 1, then the time period is taken as the target time period; if the target time period is longer than a preset time period, then the battery cell is determined to be an abnormal battery cell. The time period can be one day, and the preset time period can be two days.

[0107] In this application, for lithium iron phosphate batteries, when the remaining capacity of the battery is in the plateau region, the voltage will change when the cell is abnormal. Although the change is small, it will still occur. If the voltage difference exceeds the voltage difference threshold, the abnormal risk of the cell can be identified in time. The identification accuracy is high and it is suitable for judging the consistency of the cells. When an abnormal cell is identified, the lithium iron phosphate battery cells can be replaced or repaired in advance, which improves vehicle safety and user driving experience.

[0108] According to a second aspect of this application, an abnormal cell identification device 100 is provided, applied to a lithium iron phosphate battery, the lithium iron phosphate battery comprising a plurality of cells, the device comprising:

[0109] The first acquisition unit 101 acquires the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell.

[0110] The first determining unit 102 determines the current region where the lithium iron phosphate battery is located based on the remaining capacity of the battery. If the current region is a platform region, the configuration is as follows:

[0111] The second determining unit 103 determines a reference voltage based on the cell voltage of each of the battery cells, wherein the reference voltage is the voltage of the battery cell when it is working normally.

[0112] The third determining unit 104 determines the voltage difference between the cell voltage and the reference voltage for each cell. If the absolute value of the voltage difference is greater than or equal to the voltage difference threshold, the cell has an abnormal risk. The voltage difference threshold is a positive value and is the upper limit of the voltage difference when the cell is working normally.

[0113] In some embodiments, a fourth determining unit is further included. This fourth determining unit is configured to: after determining the current region where the lithium iron phosphate battery is located based on the remaining battery capacity, if the current region is a non-platform region, the fourth determining unit is configured to: a second obtaining unit, for each cell, obtain the remaining cell capacity of the cell based on the cell voltage; a fifth determining unit, determine a reference remaining capacity based on the remaining cell capacity of each cell, the reference remaining capacity being the remaining capacity when the cell is operating normally; and a sixth determining unit, for each cell, determine the capacity difference between the remaining cell capacity of the cell and the reference remaining capacity, if the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, then the cell has an abnormal risk, the capacity difference threshold being a positive value, and the capacity difference threshold being the upper limit of the capacity difference when the cell is operating normally.

[0114] In some embodiments, the second acquisition unit is configured as: a third acquisition unit, which acquires the remaining capacity of the battery cell from a preset relationship table based on the battery cell voltage, wherein the preset relationship table is a correspondence between voltage and remaining capacity.

[0115] In some embodiments, the fifth determining unit is configured as follows: a first determining unit, which takes a first reference value of the remaining capacity of each of the battery cells as the reference remaining capacity, wherein the first reference value includes one of the median, mode, and mean; and a second determining unit is configured as follows: a second determining unit, which takes a second reference value of the voltage of each of the battery cells as the reference battery voltage, wherein the second reference value includes one of the median, mode, and mean.

[0116] In some embodiments, a first execution unit is further included. Before acquiring the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each cell, the first execution unit is configured as follows: a fourth acquisition unit, acquiring multiple sets of vehicle data, each set of vehicle data including vehicle current, vehicle power-off duration, cell voltage of the cell, and cell temperature; and a second execution unit, for each set of vehicle data, performing the step of acquiring the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each cell when the cell voltage of the vehicle data is within a preset voltage range, the cell temperature of the cell is within a preset temperature range, the vehicle current is within a preset current range, and the vehicle power-off duration is greater than a preset duration.

[0117] In some embodiments, the first acquisition unit is configured as follows: a fifth acquisition unit, acquiring the remaining capacity of each of the battery cells; a third assignment unit, taking the maximum value as the first remaining capacity and the minimum value as the second remaining capacity among the remaining capacities of each of the battery cells; a seventh determination unit, determining the first remaining capacity difference between the first remaining capacity and the second remaining capacity; an eighth determination unit, determining the second remaining capacity difference between the maximum capacity of the lithium iron phosphate battery and the first remaining capacity difference; and a fourth assignment unit, taking the ratio between the second remaining capacity and the second remaining capacity difference as the remaining battery capacity. The maximum capacity of the lithium iron phosphate battery can be 100%, or full capacity.

[0118] In some embodiments, the device further includes: a ninth determining unit, which, for each battery cell, determines the battery cell as an abnormal battery cell if the number of abnormal risks of the battery cell is greater than or equal to a preset number within a target time period.

[0119] Based on the same inventive concept, as a third aspect, this application also provides a computer-readable storage medium storing a program product capable of implementing the abnormal battery cell identification method described above. In some possible embodiments, various aspects of this application can also be implemented as a program product including program code, which, when run on a terminal device, causes the terminal device to perform the steps described in the "Exemplary Methods" section of this specification according to various exemplary embodiments of this application.

[0120] refer to Figure 3 As shown, a program product 200 for implementing the above-described method according to an embodiment of this application is described. It may employ a portable compact disc read-only memory (CD-ROM) and include program code, and can run on a terminal device, such as a personal computer. However, the program product of this application is not limited thereto. In this document, a readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0121] The program product may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0122] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium, capable of sending, propagating, or transmitting programs for use by or in conjunction with an instruction execution system, apparatus, or device.

[0123] The program code contained on the readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0124] Program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0125] In another respect, this application also provides an electronic device capable of implementing the above-described method.

[0126] Those skilled in the art will understand that various aspects of this application can be implemented as a system, method, or program product. Therefore, various aspects of this application can be specifically implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, collectively referred to herein as a "circuit," "module," or "system."

[0127] The following reference Figure 4 To describe an electronic device 300 according to this embodiment of the present application. Figure 4 The electronic device 300 shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0128] like Figure 4 As shown, the electronic device 300 is presented in the form of a general-purpose computing device. The components of the electronic device 300 may include, but are not limited to: at least one processing unit 310, at least one storage unit 320, and a bus 330 connecting different system components (including storage unit 320 and processing unit 310).

[0129] The storage unit stores program code that can be executed by the processing unit 310, causing the processing unit 310 to perform the steps described in the "Embodiment Methods" section above according to various exemplary embodiments of this application.

[0130] Storage unit 320 may include readable media in the form of volatile storage units, such as random access memory (RAM) 321 and / or cache memory 322, and may further include read-only memory (ROM) 323.

[0131] Storage unit 320 may also include a program / utility 324 having a set (at least one) of program modules 325, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0132] Bus 330 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0133] Electronic device 300 can also communicate with one or more external devices 400 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with the electronic device 300, and / or with any device that enables the electronic device 300 to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 350. Furthermore, electronic device 300 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 360. Figure 4 As shown, network adapter 360 communicates with other modules of electronic device 300 via bus 330. It should be understood that, although not shown in the figure, other hardware and / or software modules can be used in conjunction with electronic device 300, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0134] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored as one or more instructions or codes on or transmitted via a computer-readable medium. Other examples and embodiments are within the scope and spirit of this application and the appended claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Furthermore, the functional units may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit.

[0135] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0136] The units described as separate components may or may not be physically separate. Similarly, the components of the control device may or may not be physical units; they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0137] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a 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 all or part 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 a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0138] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for identifying abnormal battery cells, characterized in that, Applied to lithium iron phosphate batteries, the lithium iron phosphate battery comprising multiple cells, the method includes: Obtain the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell; Based on the remaining capacity of the battery, determine the current region where the lithium iron phosphate battery is located. If the current region is a plateau region, determine whether the cell has any abnormal risks through the following steps: A reference voltage is determined based on the cell voltage of each of the aforementioned cells, wherein the reference voltage is the voltage at which the cell operates normally. For each of the battery cells, the voltage difference between the cell voltage and the reference voltage is determined. If the absolute value of the voltage difference is greater than or equal to the voltage difference threshold, the battery cell has an abnormal risk. The voltage difference threshold is a positive value and is the upper limit of the voltage difference when the battery cell is working normally. After determining the current region where the lithium iron phosphate battery is located based on the remaining battery capacity, if the current region is a non-platform region, the method further includes: For each battery cell, the remaining capacity of the battery cell is obtained based on the cell voltage. A reference remaining capacity is determined based on the remaining capacity of each of the battery cells, and the reference remaining capacity is the remaining capacity of the battery cell when it is working normally; For each cell, the capacity difference between the cell's remaining capacity and the reference remaining capacity is determined. If the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, the cell has an abnormal risk. The capacity difference threshold is a positive value and is the upper limit of the capacity difference when the cell is working normally.

2. The abnormal battery cell identification method according to claim 1, characterized in that, The step of obtaining the remaining capacity of the battery cell based on the cell voltage includes: Based on the cell voltage, the remaining cell capacity is obtained from a preset relationship table, where the preset relationship table is the correspondence between voltage and remaining capacity.

3. The abnormal battery cell identification method according to claim 1, characterized in that, The step of determining the reference remaining capacity based on the remaining capacity of each of the battery cells includes: The first reference value of the remaining capacity of each of the battery cells is used as the reference remaining capacity, wherein the first reference value includes one of the median, mode and mean. The step of determining the reference voltage based on the cell voltage of each of the battery cells includes: The second reference value of the cell voltage of each of the cells is used as the reference voltage, and the second reference value includes one of the median, mode and mean.

4. The abnormal battery cell identification method according to claim 1, characterized in that, Before obtaining the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell, the method further includes: Acquire multiple sets of vehicle data, each set of vehicle data including vehicle current, vehicle power-off duration, battery cell voltage, and battery cell temperature; For each set of vehicle data, if the cell voltage of the battery cell in the vehicle data is within a preset voltage range, the cell temperature of the battery cell is within a preset temperature range, the vehicle current is within a preset current range, and the vehicle power-off time is greater than a preset time, then the step of obtaining the remaining capacity of the lithium iron phosphate battery and the cell voltage of each battery cell is executed.

5. The abnormal battery cell identification method according to claim 1, characterized in that, The process of obtaining the remaining capacity of the lithium iron phosphate battery includes: Obtain the remaining capacity of each of the battery cells; Among the remaining capacity of each of the battery cells, the maximum value is taken as the first remaining capacity, and the minimum value is taken as the second remaining capacity. Determine the first remaining capacity difference between the first remaining capacity and the second remaining capacity; Determine a second remaining capacity difference between the maximum capacity of the lithium iron phosphate battery and the first remaining capacity difference; The ratio between the second remaining capacity and the difference between the second remaining capacity is taken as the remaining capacity of the battery.

6. A method for identifying abnormal battery cells according to any one of claims 1-5, characterized in that, The method further includes: For each battery cell, if the number of abnormal risks of the battery cell is greater than or equal to a preset number within the target time period, the battery cell is determined to be an abnormal battery cell.

7. An abnormal battery cell identification device, characterized in that, Applied to lithium iron phosphate batteries, wherein the lithium iron phosphate battery comprises multiple cells, the device includes: The first acquisition unit acquires the remaining capacity of the lithium iron phosphate battery and the cell voltage of each cell. The first determining unit determines the current region where the lithium iron phosphate battery is located based on the remaining capacity of the battery. If the current region is a platform region, the configuration is as follows: The second determining unit determines a reference voltage based on the cell voltage of each of the battery cells, wherein the reference voltage is the voltage of the battery cell when it is operating normally. The third determining unit determines the voltage difference between the cell voltage and the reference voltage for each cell. If the absolute value of the voltage difference is greater than or equal to the voltage difference threshold, the cell has an abnormal risk. The voltage difference threshold is a positive value and is the upper limit of the voltage difference when the cell is working normally. It also includes a fourth determining unit, which is configured to, after determining the current region where the lithium iron phosphate battery is located based on the remaining battery capacity, if the current region is a non-platform region, then: The second acquisition unit acquires the remaining capacity of each battery cell based on its cell voltage. The fifth determining unit determines a reference remaining capacity based on the remaining capacity of each of the battery cells, wherein the reference remaining capacity is the remaining capacity of the battery cell when it is working normally; The sixth determining unit determines, for each cell, the capacity difference between the cell's remaining capacity and the reference remaining capacity. If the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, then the cell has an abnormal risk. The capacity difference threshold is a positive value and is the upper limit of the capacity difference when the cell is working normally.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, The computer program includes executable instructions that, when executed by a processor, implement the method of any one of claims 1-6.

9. An electronic device, characterized in that, include: One or more processors; A memory for storing executable instructions of the processor, which, when executed by the one or more processors, cause the one or more processors to perform the method according to any one of claims 1-6.

Images