Abnormal battery cell identification method and device, medium and electronic equipment

Abstract

The invention discloses an abnormal battery cell identification method and device, a medium and electronic equipment, the method is applied to a lithium iron phosphate battery, the lithium iron phosphate battery comprises a plurality of battery cells, and the method comprises the following steps: obtaining the battery residual capacity of the lithium iron phosphate battery and the battery cell voltage of each battery cell; the current area where the lithium iron phosphate battery is located is determined according to the residual capacity of the battery, and if the current area is a platform area, whether the battery cells have abnormal risks or not is determined through the following steps that reference voltage is determined according to the battery cell voltages of all the battery cells, and the reference voltage is the voltage when the battery cells work normally; and for each battery cell, determining the voltage difference between the battery cell voltage of the battery cell and the reference voltage, if the absolute value of the voltage difference is greater than or equal to a voltage difference threshold value, determining that the battery cell has an abnormal risk, the voltage difference threshold value is a positive value, and the voltage difference threshold value is a voltage difference upper limit value when the battery cell works normally. According to the invention, the abnormal cell identification accuracy can be improved.

Description

Background Art

[0002] When testing the consistency of battery cells, the battery pack is usually tested for charge and discharge to obtain the rate of change of the capacity per unit voltage interval. The difference between each battery cell is evaluated based on the rate of change of the capacity per unit voltage interval. However, for lithium iron phosphate batteries, the open circuit voltage (OCV) curve is relatively flat, especially when it is in the platform area, the voltage change is small, making it difficult to accurately evaluate the difference between each battery cell through the rate of change of the capacity per unit voltage interval, and the accuracy of identifying abnormal batteries is low. Summary of the invention

[0003] The embodiments of the present application provide an abnormal battery cell identification method, device, medium, and electronic device for solving the technical problem that it is difficult to accurately evaluate the differences between the batteries of a lithium iron phosphate battery by the rate of change of the content within a unit voltage interval.

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

[0005] According to a first aspect of the present application, a method for identifying abnormal cells is provided, which is applied to a lithium iron phosphate battery, wherein the lithium iron phosphate battery includes a plurality of cells, and the method includes:

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

[0007] The current area where the lithium iron phosphate battery is located is determined according to the remaining capacity of the battery. If the current area is a platform area, whether the battery cell has an abnormal risk is determined by the following steps:

[0008] Determine a reference voltage according to the cell voltage of each of the cells, the reference voltage being the voltage of the cell when it is working normally;

[0009] For each of the battery cells, determine 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, there is an abnormal risk in the battery cell. The voltage difference threshold is a positive value, and the voltage difference threshold is the upper limit value of the voltage difference when the battery cell is operating normally.

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

[0011] For each battery cell, obtaining the remaining capacity of the battery cell according to the battery cell voltage of the battery cell;

[0012] Determine a reference remaining capacity according to the remaining capacity of each of the battery cells, wherein the reference remaining capacity is the remaining capacity of the battery cell when the battery cell is working normally;

[0013] For each battery cell, determine the capacity difference between the remaining capacity of the battery cell and the reference remaining capacity. If the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, there is an abnormal risk for the battery cell. The capacity difference threshold is a positive value, and the capacity difference threshold is an upper limit value of the capacity difference when the battery cell is operating normally.

[0014] In some embodiments of the present application, based on the above solution, obtaining the remaining capacity of the battery cell according to the battery cell voltage of the battery cell includes:

[0015] According to the cell voltage of the cell, the cell remaining capacity of the cell is obtained from a preset relationship table, wherein the preset relationship table is a correspondence between voltage and remaining capacity.

[0016] In some embodiments of the present application, based on the above solution, determining the reference remaining capacity according to the remaining capacity of each of the battery cells includes:

[0017] 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 a median, a mode, and a mean;

[0018] The step of determining the reference voltage according to the cell voltage of each of the cells comprises:

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

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

[0021] Acquire multiple groups of vehicle data, each group of the vehicle data includes vehicle current, vehicle power-off time, battery cell voltage and battery cell temperature of the battery cell;

[0022] For each group of vehicle data, 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, the step of obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the battery cells is performed.

[0023] In some embodiments of the present application, based on the above solution, obtaining the remaining battery capacity of the lithium iron phosphate battery includes:

[0024] Obtaining the remaining capacity of each battery cell;

[0025] Among the remaining capacities 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] determining a first remaining capacity difference between the first remaining capacity and the second remaining capacity;

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

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

[0029] In some embodiments of the present application, based on the above solution, the method further includes:

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

[0031] According to a second aspect of the present application, a device for identifying abnormal cells is provided, the device comprising:

[0032] A first acquisition unit is used to acquire the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the cells;

[0033] The first determining unit determines the current area where the lithium iron phosphate battery is located according to the remaining capacity of the battery, and if the current area is a platform area, is configured as follows:

[0034] A second determining unit, for determining a reference voltage according to a cell voltage of each of the cells, wherein the reference voltage is a voltage when the cell is working normally;

[0035] The third determination unit determines, for each of the battery cells, a 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, the battery cell has an abnormal risk; the voltage difference threshold is a positive value, and the voltage difference threshold is an upper limit value of the voltage difference when the battery cell is operating normally.

[0036] In some embodiments of the present application, based on the above scheme, a fourth determination unit is further included, and the fourth determination unit is used for, after determining the current area where the lithium iron phosphate battery is located according to the remaining capacity of the battery, if the current area is a non-platform area, the fourth determination unit is configured as follows:

[0037] A second acquisition unit, for each battery cell, acquires the remaining capacity of the battery cell according to the battery cell voltage of the battery cell;

[0038] A fifth determining unit, configured to determine a reference remaining capacity according to the remaining capacity of each of the battery cells, wherein the reference remaining capacity is the remaining capacity of the battery cell when the battery cell operates normally;

[0039] The sixth determination unit determines, for each battery cell, a capacity difference between the remaining capacity of the battery cell and the reference remaining capacity. If the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, there is an abnormal risk in the battery cell. The capacity difference threshold is a positive value, and the capacity difference threshold is an upper limit value of the capacity difference when the battery cell is operating normally.

[0040] In some embodiments of the present application, based on the above solution, the second acquisition unit is configured as follows:

[0041] The third acquisition unit acquires the remaining capacity of the battery cell from a preset relationship table according to the battery cell voltage of the battery cell, wherein the preset relationship table is a correspondence between voltage and remaining capacity.

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

[0043] First, as a unit, a 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 a median, a mode and a mean;

[0044] The second determining unit is configured as:

[0045] Second, as a unit, a second reference value of the cell voltage of each of the cell is used as the reference cell voltage, wherein the second reference value includes one of a median, a mode and a mean.

[0046] In some embodiments of the present application, based on the above solution, a first execution unit is further included, and the first execution unit is used for obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the cells. The first execution unit is configured as follows:

[0047] A fourth acquisition unit acquires multiple groups of vehicle data, each group of the vehicle data includes vehicle current, vehicle power-off time, battery cell voltage and battery cell temperature of the battery cell;

[0048] The second execution unit, for each group of the vehicle data, executes the step of obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the battery cells when the cell voltage of the battery cells in the vehicle data is within a preset voltage range, the cell temperature of the battery cells 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 the present application, based on the above solution, the first acquisition unit is configured as follows:

[0050] A fifth obtaining unit, for obtaining the remaining capacity of each of the battery cells;

[0051] Third, as a unit, among the remaining capacities of the battery cells 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;

[0052] a seventh determining unit, configured to determine a first remaining capacity difference between the first remaining capacity and the second remaining capacity;

[0053] an eighth determining unit, configured to determine a second remaining capacity difference between the maximum battery capacity of the lithium iron phosphate battery and the first remaining capacity difference;

[0054] Fourthly, as a unit, a ratio between the second remaining capacity and the second remaining capacity difference is used as the battery remaining capacity.

[0055] In some embodiments of the present application, based on the above solution, the device further includes:

[0056] A ninth determination unit determines, for each battery cell, that the battery cell is 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.

[0057] According to the third aspect of the present application, a computer-readable storage medium is provided, on which a computer program is stored, characterized in that the computer program includes executable instructions, and when the executable instructions are executed by a processor, the method described in any embodiment of the first aspect of the present application is implemented.

[0058] According to the fourth aspect of the present application, an electronic device is provided, comprising: one or more processors; and a memory for storing executable instructions of the processors, wherein when the executable instructions are executed by the one or more processors, the one or more processors implement the method described in any embodiment of the first aspect of the present 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 platform area, when the battery cell is abnormal, the voltage will change. Although the change is small, it will still change. If the voltage difference exceeds the voltage difference threshold, the risk of abnormality in the battery cell can be identified in time with high recognition accuracy.

[0061] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0063] Figure 1 A flow chart of a method for identifying abnormal cells in an embodiment of the present application is shown;

[0064] Figure 2 A block diagram of an abnormal battery cell identification device in an embodiment of the present application is shown;

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

[0066] Figure 4 A schematic diagram showing the system structure of an electronic device in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0067] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0068] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present application. However, those skilled in the art will appreciate that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, known methods, devices, realizations or operations are not shown or described in detail to avoid blurring the various aspects of the 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 may be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0070] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[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 understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0072] Figure 1 A method for identifying abnormal cells in an embodiment of the present application is shown, which is applied to a lithium iron phosphate battery. The lithium iron phosphate battery includes a plurality of cells, and the cells may be single cells. The method includes at least step S1 and step S2, which are described in detail as follows:

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

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

[0075] In step S2, the current area where the lithium iron phosphate battery is located is determined according to the remaining capacity of the battery. If the current area is a platform area, the following steps are used to determine whether the battery cell has an abnormal risk: a reference voltage is determined according to the battery cell voltage of each of the battery cells, and the reference voltage is the voltage of the battery cell when it is working normally; for each of the battery cells, a voltage difference between the battery cell voltage and the reference voltage is determined. If the absolute value of the voltage difference is greater than or equal to a pressure difference threshold, the battery cell has an abnormal risk. The pressure difference threshold is a positive value, and the pressure difference threshold is the upper limit of the pressure difference when the battery cell is working normally. On the one hand, it can be understood that if the voltage difference is greater than the pressure difference threshold or equal to the pressure difference threshold or less than the opposite of the pressure difference threshold or equal to the opposite of the pressure difference threshold, the battery cell has an abnormal risk. On the other hand, it can be understood as screening |△vol ij |>λ_vol is a cell with abnormal risk, △vol ij is the voltage difference, and λ_vol is the parameter of the abnormal cell, that is, the voltage difference threshold. Steps S1 to S2 can be processed by the cloud to improve processing efficiency.

[0076] In the prior art, when the lithium iron phosphate battery is in the platform area, if the cell difference is evaluated by the rate of change of the capacity within the unit voltage interval, that is, the cell difference is evaluated according to the ratio of the capacity change to the voltage change (unit voltage interval), the voltage change of the abnormal cell is larger than that of the normal cell, but the order of magnitude of the capacity change is greater than that of the voltage change, so that the rate of change of the capacity within the unit voltage interval of the abnormal cell is not much different from that of the normal cell, which is not conducive to identifying the abnormal cell. In the present application, the lithium iron phosphate battery is in the platform area, and the cell difference is evaluated according to the ratio of the capacity change to the voltage change (unit voltage interval). Compare the voltage difference and the voltage difference threshold to determine whether the battery cell has an abnormal risk. Compared with normal batteries, abnormal batteries have a larger voltage change. Although the difference is not large, the voltage difference between abnormal batteries and normal batteries can be distinguished by setting a moderate voltage difference threshold. For example, the voltage difference of normal batteries is below 100mV, and the voltage difference of abnormal batteries is above 100mV. By setting the voltage difference threshold to 100mV, abnormal batteries and normal batteries can be clearly distinguished, thereby accurately identifying abnormal batteries, that is, judging batteries with abnormal risks. Among them, the rate of change of capacity per unit voltage interval can be obtained through the dQ / dV curve (differential capacity curve).

[0077] It should be noted that the platform area refers to a region in the charge and discharge curve of the lithium iron phosphate battery where the voltage changes relatively smoothly and stably. In the platform area, the voltage of the lithium iron phosphate battery drops or rises slowly, which is equivalent to the lithium iron phosphate battery being in a relatively stable state.

[0078] In some embodiments, the voltage difference threshold is 100 mV to 300 mV.

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

[0080] In some embodiments, for each battery cell module, the temperature detected by one of the probes is T1, and the temperature detected by another probe is T2, then the temperature of the battery cell is T1 or T2 or (T1+T2) / 2.

[0081] In some embodiments, if the absolute value of the voltage difference is less than the voltage difference threshold, the battery cell has no abnormal risk, that is, if the voltage difference is greater than the inverse of the voltage difference threshold and less than the voltage difference threshold, the battery cell has no abnormal risk.

[0082] In some embodiments, after determining the current area where the lithium iron phosphate battery is located according to the battery remaining capacity, if the current area is a non-platform area, the method further includes: for each battery cell, obtaining the battery cell remaining capacity of the battery cell according to the battery cell voltage of the battery cell; determining the reference remaining capacity according to the battery cell remaining capacity of each of the battery cells, the reference remaining capacity being the remaining capacity when the battery cell is working normally; for each battery cell, determining the capacity difference between the battery cell remaining capacity and the reference remaining capacity, if the absolute value of the capacity difference is greater than or equal to the capacity difference threshold, then the battery cell has an abnormal risk, the capacity difference threshold is a positive value, and the capacity difference threshold is the upper limit of the capacity difference when the battery cell is working normally. On the one hand, it can be understood that if the capacity difference is greater than the capacity difference threshold or equal to the capacity difference threshold or less than the opposite of the capacity difference threshold or equal to the opposite of the capacity difference threshold, then the battery cell has an abnormal risk, and on the other hand, it can be understood as screening |△SOC ij |>λ_soc is a cell with abnormal risk, △SOC ij is the capacity difference, λ_soc is the parameter of the cell abnormality, that is, the capacity difference threshold. The remaining capacity of the cell is the real SOC of the cell, which can be recorded as SOC_Real.

[0083] It should be noted that the non-platform area refers to a region in the charge and discharge curve of the lithium iron phosphate battery where the voltage changes greatly. In the non-platform area, the voltage of the lithium iron phosphate battery drops or rises faster. It can also be said that the voltage drops or rises faster than when the lithium iron phosphate battery is in the platform area.

[0084] In the present application, when the lithium iron phosphate battery is in the non-platform area, a normal battery cell will also have a large voltage difference. If the voltage difference is used for evaluation, the normal battery cell is easily evaluated as an abnormal battery cell, resulting in a misjudgment. The abnormal battery cell will have a large capacity difference, and the normal battery cell will not have a large capacity difference. If the capacity difference is used to evaluate whether the battery cell has an abnormal risk, it is not easy to make a misjudgment and the evaluation accuracy is high.

[0085] In some embodiments, the current area where the lithium iron phosphate battery is located is determined according to the remaining capacity of the battery, including: if the remaining capacity of the battery is 30%-95%, the current area is a platform area; if the remaining capacity of the battery is 0 to 30%, the current area is a non-platform area, that is, according to the remaining capacity of the battery, the lithium iron phosphate battery is located at the platform area or the non-platform area at the current moment. When the lithium iron phosphate battery is in the platform area, 30% ≤ SOC internal ≤95%, when the lithium iron phosphate battery is in the non-platform area, 0≤SOC internal <30%, SOC internal It is the remaining capacity of the battery or the internal SOC.

[0086] In some embodiments, the obtaining of the remaining capacity of the battery cell according to the battery cell voltage of the battery cell comprises: obtaining the remaining capacity of the battery cell from a preset relationship table according to the battery cell voltage of the battery cell, wherein the preset relationship table is a correspondence between voltage and remaining capacity. The preset relationship table may be an OCV-SOC table of a battery pack, wherein the OCV-SOC table is a relationship table between open circuit voltage (OCV) and remaining capacity (SOC).

[0087] For example, according to the cell voltage U and the OCV-SOC table of the battery pack, the real SOC, i.e., the remaining capacity of the cell, is obtained by looking up the table, i.e., SOC_Real ij ,i∈[1,m],j∈[1,n], i is the i-th group of data, m is the m-th group of data, j is the j-th battery cell, n is the lithium iron phosphate battery with n batteries, SOC_Real ij is the actual SOC of the jth cell in the i-th group of data.

[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, the first reference value including one of a median, a mode and a mean; determining the reference voltage based on the cell voltage of each of the battery cells includes: using a second reference value of the cell voltage of each of the battery cells as the reference cell voltage, the second reference value including one of a median, a mode and a mean.

[0089] In some embodiments, the first reference value is the median, and the second reference value is the median. When the cell voltages of the individual cells are stratified, the median is more representative. For example, the lithium iron phosphate includes 100 cells, 50 of which have a cell voltage of 3.4-3.5V, and 50 of which have a cell voltage of 3.2-3.3V. If the mean is used, the mean is 3.35V, which obviously cannot represent the actual situation of the cell voltage. The median is more representative. Similarly, the remaining cell capacity of 50 cells is 60%-61%, and the cell voltage of 50 cells is 58%-59%. If the mean is used, the mean is 59.5%, which obviously cannot represent the actual situation of the remaining cell capacity. The median is more representative.

[0090] In some embodiments, when the first reference value includes a 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 is the median of the real SOC of each battery cell in the i-th group of data, median is a function for calculating the median, i is the i-th group of data, m is the m-th group of data, j is the j-th battery cell, n is the lithium iron phosphate battery with n batteries, SOC_Real ij is the actual SOC of the jth cell in the i-th group of data.

[0092] In some embodiments, when the first reference value includes a median, the capacity difference is determined by the following formula: ΔSOC ij =SOC_Real ij -SOC_Median i ,i∈[1,m],j∈[1,n],△SOC ij is the capacity difference of the jth battery cell in the i-th group of data, i is the i-th group of data, m is the m-th group of data, j is the j-th battery cell, n is the lithium iron phosphate battery with n batteries, SOC_Real ij is the actual SOC of the jth cell in the i-th group of data, SOC_Median i is the median of the actual SOC of each of the cells in the i-th group of data.

[0093] In some embodiments, when the second reference value includes a median, the second reference value is determined by the following formula: vol_Median i=median(vol i1 ,vol i2 ..., vol ij ),i∈[1,m],j∈[1,n], vol_Median i is the median of the cell voltages of the cells in the i-th group of data, median is a function for calculating the median, i is the i-th group of data, m is the m-th group of data, j is the j-th cell, n is the lithium iron phosphate battery with n cells, vol ij The cell voltage of the jth cell in the i-th group of data.

[0094] In some embodiments, when the second reference value includes a 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 is the voltage difference of the jth battery cell in the i-th group of data, i is the i-th group of data, m is the m-th group of data, j is the j-th battery cell, n is the lithium iron phosphate battery with n batteries, vol ij The cell voltage of the jth cell in the i-th group of data, vol_Median i is the median of the cell voltages of the cells in the i-th group of data.

[0095] In some embodiments, before obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the cells, the method further includes: obtaining multiple groups of vehicle data, each group of the vehicle data includes vehicle current, vehicle power-off duration, cell voltage of the cells, and cell temperature; for each group of the vehicle data, when the cell voltage of the cells in the vehicle data is within a preset voltage range, the cell temperature of the cells 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, the step of obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the cells is performed. Each group of the vehicle data can be each frame of data uploaded by the vehicle to the cloud. The multiple groups of vehicle data can be national standard historical data of the vehicle within a 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 cell voltage of the battery cell in the vehicle data is within the preset voltage range and the cell temperature of the battery cell is within the preset temperature range, then the vehicle data is normal data; if the vehicle data is not within the preset voltage range or the cell temperature of the battery cell is not within the preset temperature range, then the vehicle data is abnormal data; therefore, filtering the abnormal data in the vehicle data can increase data reliability; if the vehicle current of the vehicle data is within the preset current range and the vehicle power-off time is greater than the preset time, then the vehicle data is static data; if the vehicle current of the vehicle data is not within the preset current range or the vehicle power-off time is not greater than the preset time, then the vehicle data is non-static data; therefore, filtering the non-static data in the vehicle data can further improve data reliability.

[0097] In some embodiments, 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 time length is 1 hour or 2 hours.

[0098] In some embodiments, the obtaining of the remaining battery capacity of the lithium iron phosphate battery includes: obtaining the remaining battery capacity of each of the battery cells; taking the maximum value of the remaining battery capacity of each of the battery cells as the first remaining capacity and the minimum value as the second remaining capacity; determining the first remaining capacity difference between the first remaining capacity and the second remaining capacity; determining the second remaining capacity difference between the maximum battery capacity of the lithium iron phosphate battery and the first remaining capacity difference; 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 SOC of the lithium iron phosphate battery.

[0099] In some embodiments, 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 is the first remaining capacity, Max is a function to calculate the maximum value, SOC_Real ij is the actual SOC of the jth battery cell in the i-th group of data, i is the i-th group of data, m is the m-th group of data, j is the j-th battery cell, and n is the lithium iron phosphate battery with n batteries.

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

[0102] SOC_real min =Max(SOC_Real i1 ,SOC_Real i2 , ..., SOC_Real ij ),i∈[1,m],j∈[1,n], SOC_real min is the second remaining capacity, Min is a function to calculate the maximum value, SOC_Real ij is the actual SOC of the jth battery cell in the i-th group of data, i is the i-th group of data, m is the m-th group of data, j is the j-th battery cell, and n is the lithium iron phosphate battery with n batteries.

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

[0104] SOC internal = maximum battery capacity of the lithium iron phosphate battery × SOC_real min / [The maximum battery capacity of the lithium iron phosphate battery - (SOC_real max -SOC_real min )],SOC internal SOC_real is the remaining battery capacity. min is the second remaining capacity, SOC_real max is 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 the target period, determining the battery cell as an abnormal battery cell. The preset number is greater than or equal to 1.

[0106] In some embodiments, the multiple groups of vehicle data may be national standard historical data of the vehicle within a week, and the method further includes: within a 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 used as a target time period, and if the target time period is greater than a preset time period, then the battery cell is determined to be an abnormal battery cell. The time period may be one day, and the preset time period may be 2 days.

[0107] In the present application, for lithium iron phosphate batteries, when the remaining capacity of the battery is in the platform area, when the battery cell is abnormal, the voltage will change. Although the change is small, it will also change. If the voltage difference exceeds the voltage difference threshold, the battery cell can be identified in time for abnormal risk. The recognition accuracy is high and it is suitable for judging the consistency of the battery cell. When the abnormal battery cell is identified, the battery cell of the lithium iron phosphate battery is replaced or repaired in advance, which improves the safety of the vehicle and the user's driving experience.

[0108] According to a second aspect of the present application, an abnormal cell identification device 100 is provided, the device comprising:

[0109] A first acquisition unit 101 is configured to acquire the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each cell;

[0110] The first determining unit 102 determines the current area where the lithium iron phosphate battery is located according to the remaining capacity of the battery, and if the current area is a platform area, is configured as follows:

[0111] A second determining unit 103 determines a reference voltage according to the cell voltage of each of the cells, wherein the reference voltage is the voltage of the cell when the cell is working normally;

[0112] The third determination unit 104 determines, for each of the battery cells, a 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, the battery cell has an abnormal risk. The voltage difference threshold is a positive value, and the voltage difference threshold is an upper limit value of the voltage difference when the battery cell is operating normally.

[0113] In some embodiments, a fourth determination unit is further included, and the fourth determination unit is used for, after determining the current area where the lithium iron phosphate battery is located according to the battery remaining capacity, if the current area is a non-platform area, the fourth determination unit is configured as: a second acquisition unit, for each battery cell, acquiring the battery remaining capacity of the battery cell according to the battery cell voltage of the battery cell; a fifth determination unit, for determining a reference remaining capacity according to the battery remaining capacity of each battery cell, the reference remaining capacity being the remaining capacity when the battery cell is working normally; a sixth determination unit, for each battery cell, determining the capacity difference between the battery remaining capacity of the battery 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 there is an abnormal risk for the battery cell, and the capacity difference threshold is a positive value, and the capacity difference threshold is an upper limit value of the capacity difference when the battery cell is working 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 according to the battery cell voltage of the battery cell, and the preset relationship table is a correspondence between voltage and remaining capacity.

[0115] In some embodiments, the fifth determination unit is configured as: first as a unit, taking a first reference value of the remaining cell capacity of each of the battery cells as the reference remaining capacity, the first reference value including one of a median, a mode and a mean; the second determination unit is configured as: second as a unit, taking a second reference value of the cell voltage of each of the battery cells as the reference cell voltage, the second reference value including one of a median, a mode and a mean.

[0116] In some embodiments, a first execution unit is further included, and the first execution unit is used to, before the obtaining of the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the battery cells, the first execution unit is configured as: a fourth acquisition unit, obtaining multiple groups of vehicle data, each group of the vehicle data including vehicle current, vehicle power-off time, cell voltage and cell temperature of the battery cells; a second execution unit, for each group of the vehicle data, 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, executes the step of obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the battery cells.

[0117] In some embodiments, the first acquisition unit is configured as follows: a fifth acquisition unit, acquiring the cell remaining capacity of each of the cells; a third unit, taking the maximum value as the first remaining capacity and the minimum value as the second remaining capacity among the cell remaining capacities of each of the 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; a fourth unit, taking the ratio between the second remaining capacity and the second remaining capacity difference as the battery remaining 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 determination unit, for each battery cell, determining that the battery cell is an abnormal battery cell if the number of abnormal risks of the battery cell within a target time period is greater than or equal to a preset number.

[0119] Based on the same inventive concept, as a third aspect, the present application also provides a computer-readable storage medium on which is stored a program product capable of implementing the above-mentioned abnormal battery cell identification method of this specification. In some possible implementations, various aspects of the present application can also be implemented in the form of a program product, which includes a program code. When the program product is run on a terminal device, the program code is used to enable the terminal device to execute the steps described in the above-mentioned "Exemplary Method" section of this specification according to various exemplary implementations of the present application.

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

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

[0122] Computer readable signal media may include data signals propagated in baseband or as part of a carrier wave, in which readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Readable signal media may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0123] The program code embodied on the readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the foregoing.

[0124] Program code for performing the operations of the present application may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., using an Internet service provider to connect through the Internet).

[0125] As another aspect, the present application also provides an electronic device capable of implementing the above method.

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

[0127] Refer to the following Figure 4 The electronic device 300 according to this embodiment of the present application is described. Figure 4 The electronic device 300 shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0128] like Figure 4 As shown, the electronic device 300 is in the form of a general 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 the storage unit 320 and the processing unit 310).

[0129] The storage unit stores program codes, which can be executed by the processing unit 310, so that the processing unit 310 executes the steps described in the above “Example Method” section of this specification according to various exemplary implementations of the present application.

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

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

[0132] Bus 330 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0133] The electronic device 300 may also communicate with one or more external devices 400 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), one or more devices that enable a user to interact with the electronic device 300, and / or any device that enables the electronic device 300 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed through an input / output (I / O) interface 350. Furthermore, the electronic device 300 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through a network adapter 360. Figure 4 As shown, the network adapter 360 communicates with other modules of the electronic device 300 via the 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 the 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 a computer-readable medium or transmitted via a computer-readable medium. Other examples and implementations are within the scope and spirit of the present 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, hard wiring, or a combination of any of these. In addition, each functional unit may be integrated into a processing unit, each unit may exist physically separately, or two or more units may be integrated into one 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. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0136] The units described as separate components may or may not be physically separated, and the components of the control device may or may not be physical units, that is, they may be located in one place or distributed in multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0137] If the integrated unit is implemented in the form of 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 the present application can be essentially or partly or all or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, disk or optical disk, etc., which can store program code.

[0138] The above description is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A method for identifying abnormal battery cells, characterized in that: Applied to a lithium iron phosphate battery, the lithium iron phosphate battery includes a plurality of battery cells, and the method includes: Obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the cells; The current area where the lithium iron phosphate battery is located is determined according to the remaining capacity of the battery. If the current area is a platform area, whether the battery cell has an abnormal risk is determined by the following steps: Determine a reference voltage according to the cell voltage of each of the cells, the reference voltage being the voltage of the cell when it is working normally; For each of the battery cells, determine 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, there is an abnormal risk in the battery cell. The voltage difference threshold is a positive value, and the voltage difference threshold is the upper limit value of the voltage difference when the battery cell is operating normally.

2. The abnormal cell identification method according to claim 1, characterized in that: After determining the current area where the lithium iron phosphate battery is located according to the remaining capacity of the battery, if the current area is a non-platform area, the method further includes: For each battery cell, obtaining the remaining capacity of the battery cell according to the battery cell voltage of the battery cell; Determine a reference remaining capacity according to the remaining capacity of each of the battery cells, wherein the reference remaining capacity is the remaining capacity of the battery cell when the battery cell is working normally; For each battery cell, determine the capacity difference between the remaining capacity of the battery cell and the reference remaining capacity. If the absolute value of the capacity difference is greater than or equal to a capacity difference threshold, there is an abnormal risk for the battery cell. The capacity difference threshold is a positive value, and the capacity difference threshold is an upper limit value of the capacity difference when the battery cell is operating normally.

3. The abnormal cell identification method according to claim 2, characterized in that: The obtaining the remaining capacity of the battery cell according to the battery cell voltage of the battery cell comprises: According to the cell voltage of the cell, the cell remaining capacity of the cell is obtained from a preset relationship table, wherein the preset relationship table is a correspondence between voltage and remaining capacity.

4. The abnormal cell identification method according to claim 2, characterized in that: The determining the reference remaining capacity according to the remaining capacity of each of the battery cells comprises: 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 a median, a mode, and a mean; The step of determining the reference voltage according to the cell voltage of each of the cells comprises: A second reference value of the cell voltage of each of the cell is used as the reference cell voltage, wherein the second reference value includes one of a median, a mode and a mean.

5. The abnormal cell identification method according to claim 1, characterized in that: Before obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the cells, the method further includes: Acquire multiple groups of vehicle data, each group of the vehicle data includes vehicle current, vehicle power-off time, battery cell voltage and battery cell temperature of the battery cell; For each group of vehicle data, 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, the step of obtaining the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the battery cells is performed.

6. The abnormal cell identification method according to claim 1, characterized in that: The obtaining of the remaining battery capacity of the lithium iron phosphate battery includes: Obtaining the remaining capacity of each battery cell; Among the remaining capacities 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; 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 battery capacity of the lithium iron phosphate battery and the first remaining capacity difference; The ratio between the second remaining capacity and the second remaining capacity difference is used as the battery remaining capacity.

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

8. An abnormal battery cell identification device, characterized in that: The device comprises: A first acquisition unit is used to acquire the remaining battery capacity of the lithium iron phosphate battery and the cell voltage of each of the cells; The first determining unit determines the current area where the lithium iron phosphate battery is located according to the remaining capacity of the battery, and if the current area is a platform area, is configured as follows: A second determining unit, for determining a reference voltage according to a cell voltage of each of the cells, wherein the reference voltage is a voltage when the cell is working normally; The third determination unit determines, for each of the battery cells, a 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, the battery cell has an abnormal risk; the voltage difference threshold is a positive value, and the voltage difference threshold is an upper limit value of the voltage difference when the battery cell is operating normally.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program includes executable instructions, and when the executable instructions are executed by a processor, the method described in any one of claims 1 to 7 is implemented.

10. An electronic device, characterized in that: include: one or more processors; A memory for storing executable instructions of the processor, wherein when the executable instructions are executed by the one or more processors, the one or more processors implement the method according to any one of claims 1 to 7.

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