Deviation estimation method for calculating capacity irregularity abnormity caused by voltage irregularity

Abstract

The invention discloses a deviation estimation method for calculating capacity irregularity abnormity caused by voltage irregularity, which comprises the following steps: acquiring target abnormal monomer voltage data and other monomer voltage data except the target abnormal monomer voltage data, and calculating other monomer voltage mean value data, performing smoothing processing on the target abnormal monomer voltage data and the other monomer voltage mean value data, constructing an SOC curve graph for the battery module test, and searching an SOC value corresponding to the abnormal monomer voltage data and an SOC value corresponding to the other monomer voltage mean value data, obtaining the abnormal monomer voltage and a charging and discharging time point corresponding to an average monomer voltage reflected by the average value data of the rest monomer voltages, calculating the charging and discharging electric quantity of the abnormal monomer voltage and the average monomer voltage, calculating the capacity deviation value according to the charging and discharging electric quantity, and dividing the capacity deviation degree, and the capacity deviation is corrected according to the deviation degree, so that the accuracy and the universality in the capacity estimation process are ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of battery detection, and in particular to a method for estimating a deviation of a capacity unevenness abnormality caused by voltage unevenness. Background Art

[0002] Uneven battery voltage and capacity usually occur in battery modules, especially when the battery module is composed of multiple battery cells connected in series or in parallel. When the voltage of one or more battery cells is uneven, the capacity of the entire battery module will be affected, and the performance and life of the entire battery module may be limited by the weakest battery cell. At the same time, uneven voltage will shorten the cycle life and cause some battery cells to enter the protection state prematurely, thereby accelerating aging and shortening the service life of the entire battery module. Uneven voltage distribution will reduce energy conversion efficiency and increase energy loss.

[0003] In the use and research of battery modules, inconsistent cell voltages often occur. This voltage inconsistency may further lead to uneven battery capacity, thereby affecting the overall performance and life of the battery module. However, the existing detection methods often find it difficult to accurately evaluate the capacity deviation caused by voltage inconsistency, which brings great difficulties to the quality control, fault diagnosis and subsequent optimization and adjustment of battery modules. Therefore, there is an urgent need for an effective method that can accurately calculate the abnormal capacity deviation caused by voltage abnormality.

[0004] The Chinese patent publication number: CN 111781529 A discloses a method and device for estimating the capacity of a battery pack based on electric vehicle cloud data. The core technical solution is to obtain the capacity of a first battery pack based on the charging data of the electric vehicle cloud by using the ampere-hour integration method, and then correct the first battery pack capacity through the fuzzy Kalman filter algorithm to obtain the capacity of a second battery pack. Based on the single cell voltage data of the electric vehicle cloud, the remaining charge power of the single cell is estimated. Based on the single cell voltage data of the electric vehicle cloud, the remaining discharge power of the single cell is estimated. According to the second battery pack capacity, the remaining charge power of the single cell and the remaining discharge power of the single cell, the single cell capacity of the battery pack is calculated.

[0005] When performing capacity estimation, the existing technology fails to take into account the uneven capacity caused by uneven voltage in different scenarios, and does not smooth the data. It is impossible to ensure that errors in the data during capacity estimation will not cause deviations in capacity estimation and that the capacity of the battery module is estimated in different scenarios.

[0006] The present invention proposes a solution to the above shortcomings as follows: obtain target abnormal cell voltage data and other cell voltage data except the target abnormal cell voltage data, calculate the mean value data of the remaining cell voltages, smooth the target abnormal cell voltage data and the mean value data of the remaining cell voltages, construct an SOC curve diagram for the battery module test, find the SOC value corresponding to the abnormal cell voltage data and the SOC value corresponding to the mean value data of the remaining cell voltages, obtain the abnormal cell voltage and the charging and discharging time points corresponding to the average cell voltage reflected by the mean value data of the remaining cell voltages, calculate the charging and discharging amount of the abnormal cell voltage and the average cell voltage, calculate the capacity deviation value according to the charging and discharging amount, divide the capacity deviation degree according to the calculation result, and correct the capacity deviation according to the deviation degree, so as to ensure the accuracy and versatility in the capacity estimation process. Summary of the invention

[0007] In order to solve the above-mentioned technical problems, the present invention provides a method for estimating the deviation of capacity unevenness caused by calculating voltage unevenness.

[0008] The technical solution of the present invention is implemented as follows: a method for estimating the deviation of capacity unevenness caused by voltage unevenness, comprising:

[0009] S1, obtaining target abnormal monomer voltage data and remaining monomer voltage data except the target abnormal monomer voltage data, and calculating the remaining monomer voltage mean data;

[0010] S2, smoothing the target abnormal monomer voltage data and the remaining monomer voltage mean value data;

[0011] S3, constructing an SOC curve diagram for the battery module test, finding the SOC value corresponding to the abnormal cell voltage data and the SOC value corresponding to the average cell voltage data of the remaining cells, and obtaining the charging and discharging time points corresponding to the abnormal cell voltage and the average cell voltage reflected by the average cell voltage of the remaining cells;

[0012] S4, calculating the charge and discharge quantity of the abnormal cell voltage and the average cell voltage;

[0013] S5. Calculate the capacity deviation value according to the charge and discharge quantity of the abnormal single cell voltage and the average single cell voltage obtained in step S4, divide the capacity deviation degree according to the calculation result, and correct the capacity deviation according to the deviation degree.

[0014] Furthermore, in the step S1, target abnormal cell voltage data and remaining cell voltage data except the target abnormal cell voltage data are obtained, and mean value data of the remaining cell voltages are calculated:

[0015] A voltage sensor is installed in the battery module to measure the cell voltage data of each single cell, a measurement time is set to measure the voltage data, the cell voltage mean data is calculated, a voltage error threshold is set, the cell voltage mean data is combined with the cell voltage data to perform a voltage error threshold judgment, the judgment is that when the cell voltage data minus the cell voltage mean data is greater than the threshold, it is marked as target abnormal cell voltage data, the target abnormal cell voltage data is counted, and the remaining cell voltage data except the target abnormal cell voltage data are sorted, and the remaining cell voltage mean data except the target abnormal cell voltage data are calculated to obtain the target abnormal cell voltage data sequence V A and the remaining monomer voltage mean value data sequence V B .

[0016] Furthermore, in the step S2, the target abnormal cell voltage data and the remaining cell voltage mean value data are smoothed:

[0017] The target abnormal monomer voltage data marked in step S1 and the calculated remaining monomer voltage mean data are smoothed using a moving average smoothing algorithm. The smoothing calculation of the marked target abnormal monomer voltage data is:

[0018]

[0019] Among them, V A 'The target abnormal monomer voltage data after smoothing, m is the moving average window size, k is the current data point index, j is the data point index variable, V A (j) is the target abnormal monomer voltage mean data obtained at index j;

[0020] The remaining monomer voltage mean data smoothing calculation is as follows:

[0021]

[0022] Among them, V B 'The remaining single-cell voltage mean data after smoothing, m is the moving average window size, k is the current data point index, j is the data point index variable, V A (j) is the average voltage data of the remaining cells obtained at index j.

[0023] Furthermore, in the step S3, an SOC curve is constructed for the battery module test, the SOC value corresponding to the abnormal cell voltage data and the SOC value corresponding to the average cell voltage data of the remaining cells are found, and the charging and discharging time points corresponding to the abnormal cell voltage and the average cell voltage reflected by the average cell voltage of the remaining cells are obtained:

[0024] The battery module is tested by a constant current charge and discharge method, the voltage data and time data of the single battery during the charge and discharge process are collected, the SOC value of each single battery at different times is calculated, the SOC value of each single battery at different times is collected to construct an SOC curve, and the high SOC interval and the low SOC interval are divided, the SOC value when the high SOC interval and the low SOC interval appear abnormal state is corrected, and the corrected SOC value is combined with the SOC value of each single battery at different times to further improve the SOC curve, wherein the high SOC interval and the low SOC interval correspond to 90%-100% and 0%-10% of the SOC respectively, and the abnormal state is divided into:

[0025] During the charging process, overcharging occurs in the high SOC range;

[0026] During the discharge process, over-discharge occurs in the low SOC range;

[0027] Find the charging and discharging time point according to the target abnormal cell voltage data smoothed in step S2 and the SOC value of the remaining cell voltage data;

[0028] Furthermore, the SOC value of each single battery at different times is calculated as:

[0029] Charging status:

[0030]

[0031] Wherein, SOC(t) is the state of charge of the battery at the charging time t, SOC(t0) is the state of charge at the start of charging, I is the constant current, t is the current charging process time, t0 is the charging start time, and C is the rated capacity of the battery;

[0032] Discharge status:

[0033]

[0034] Among them, SOC(t) is the state of charge of the battery at the discharge time t, SOC(t0) is the state of charge at the start of discharge, I is the constant current, t is the current discharge process time, t0 is the discharge start time, and C is the rated capacity of the battery.

[0035] Furthermore, in the step S4, the charge and discharge quantity of the abnormal cell voltage and the average cell voltage is calculated:

[0036] The abnormal cell voltage data SOC value and the average cell voltage SOC value found by the SOC curve constructed in step S3, the charging time t1 and the discharging time t2 determined by the SOC values ​​corresponding to the abnormal cell voltage under charging conditions, and the charging time t3 and the discharging time t4 determined by the average cell voltage, are used to calculate the charge and discharge power respectively, which is calculated as:

[0037] Abnormal charging state single cell voltage:

[0038] Q1=I×(t1-t0)

[0039] Among them, Q1 is the charging power of the charging process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, I is the constant current, t0 is the starting time of the charging process, and t1 is the end time of the abnormal cell in the charging process;

[0040] Average single cell voltage in charging state:

[0041] Q2=I×(t3-t0)

[0042] Wherein, Q2 is the charging capacity during the charging process from the initial SOC value to the SOC value corresponding to the average cell voltage, I is the constant current, t0 is the starting time of the charging process, and t3 is the end time of the average cell in the charging process;

[0043] Abnormal discharge state single cell voltage:

[0044] Q3=I×(t2-t0)

[0045] Among them, Q3 is the discharge power during the discharge process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, I is the constant current, t0 is the start time of the abnormal cell during the discharge process, and t2 is the end time of the abnormal cell during the discharge process;

[0046] Average single cell voltage in discharge state:

[0047] Q4=I×(t4-t0)

[0048] Among them, Q4 is the discharge power of the discharge process from the initial SOC value to the SOC value corresponding to the average cell voltage, I is the constant current, t0 is the start time of the average cell voltage in the discharge process, and t3 is the end time of the average cell in the discharge process.

[0049] Furthermore, in step S5, a capacity deviation value is calculated based on the charge and discharge quantity of the abnormal cell voltage and the average cell voltage obtained in step S4, the capacity deviation degree is divided according to the calculation result, and the capacity deviation is corrected according to the deviation degree:

[0050] According to the abnormal single cell voltage charge and discharge capacity calculated in step S4 and the average single cell charge and discharge capacity, the capacity deviation is calculated as:

[0051] State of charge capacity deviation:

[0052]

[0053] Among them, ΔP1 is the capacity deviation degree during the charging process, Q1 is the charging power during the charging process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, and Q2 is the charging power during the charging process from the initial SOC value to the SOC value corresponding to the average cell voltage;

[0054] Discharge state capacity deviation:

[0055]

[0056] Among them, ΔP2 is the capacity deviation degree during the discharge process, Q3 is the discharge capacity during the discharge process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, and Q4 is the discharge capacity during the discharge process from the initial SOC value to the SOC value corresponding to the average cell voltage;

[0057] The calculated charge and discharge capacity deviation results are divided into capacity deviation degrees, and when the capacity deviation results reach the divided deviation degrees, correction measures are taken to correct them;

[0058] Furthermore, the degree of deviation is divided into:

[0059] When the capacity deviation degree is between 0% and 5% and equal to 5%, it is a slight deviation;

[0060] When the capacity deviation degree is between 5% and 15% and equal to 15%, it is a moderate deviation;

[0061] When the degree of volume deviation is greater than 15%, it is considered a severe deviation;

[0062] Furthermore, the corrective measures are:

[0063] When the capacity deviation is slight, it is corrected by performing a replenishing discharge operation;

[0064] When the capacity deviation is moderate, the balanced charging control is combined with the replenishment discharge operation to make corrections;

[0065] When the capacity deviation is severe, stop using the battery and contact maintenance personnel for repair.

[0066] Beneficial effects:

[0067] The present invention aims at the shortcomings of the prior art that the error in data during capacity estimation cannot be ensured, resulting in deviation in capacity estimation, and that the battery module performs capacity estimation in different scenarios. The present invention obtains target abnormal cell voltage data and the remaining cell voltage data except the target abnormal cell voltage data, calculates the remaining cell voltage mean data, smoothes the target abnormal cell voltage data and the remaining cell voltage mean data, constructs an SOC curve for battery module testing, searches for the SOC value corresponding to the abnormal cell voltage data and the SOC value corresponding to the remaining cell voltage mean data, obtains the abnormal cell voltage and the charging and discharging time points corresponding to the average cell voltage reflected by the remaining cell voltage mean data, calculates the charging and discharging amount of the abnormal cell voltage and the average cell voltage, calculates the capacity deviation value according to the charging and discharging amount, divides the capacity deviation degree according to the calculation result, and corrects the capacity deviation according to the deviation degree, thereby ensuring the accuracy and versatility in the process of capacity estimation. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a structural block diagram of a method for estimating deviation of capacity unevenness caused by voltage unevenness in an embodiment of the present invention;

[0069] Figure 2 A flow chart of the steps of calculating capacity deviation of a method for estimating deviation of capacity deviation abnormality caused by voltage unevenness in an embodiment of the present invention;

[0070] Figure 3 The present invention is a flowchart of a method for estimating a deviation of a capacity unevenness abnormality caused by voltage unevenness in an embodiment of the present invention. DETAILED DESCRIPTION

[0071] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0072] The preferred implementation methods of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these implementation methods are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0073] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0074] See also Figure 1-Figure 3 As shown, a method for estimating the deviation of capacity unevenness caused by voltage unevenness includes:

[0075] S1, obtaining target abnormal monomer voltage data and remaining monomer voltage data except the target abnormal monomer voltage data, and calculating the remaining monomer voltage mean data;

[0076] S2, smoothing the target abnormal monomer voltage data and the remaining monomer voltage mean value data;

[0077] S3, constructing an SOC curve diagram for the battery module test, finding the SOC value corresponding to the abnormal cell voltage data and the SOC value corresponding to the average cell voltage data of the remaining cells, and obtaining the charging and discharging time points corresponding to the abnormal cell voltage and the average cell voltage reflected by the average cell voltage of the remaining cells;

[0078] S4, calculating the charge and discharge quantity of the abnormal cell voltage and the average cell voltage;

[0079] S5. Calculate the capacity deviation value according to the charge and discharge quantity of the abnormal single cell voltage and the average single cell voltage obtained in step S4, divide the capacity deviation degree according to the calculation result, and correct the capacity deviation according to the deviation degree.

[0080] like Figure 3 As shown, in step S1, target abnormal cell voltage data and remaining cell voltage mean data except the target abnormal cell voltage data are obtained, and the remaining cell voltage mean data are calculated.

[0081] Specifically, a voltage sensor is installed in the battery module to measure the cell voltage data on each single cell, and the measurement time is once every 10 seconds. The voltage sensor is an LTC6813-1 voltage sensor, and the cell voltage mean data is calculated. The voltage error threshold is set to 0.2 volts, and the cell voltage mean data is combined with the cell voltage data to perform a voltage error threshold judgment. The judgment is that when the cell voltage data minus the cell voltage mean data is greater than 0.2 volts, it is marked as target abnormal cell voltage data, and the target abnormal cell voltage data is counted, and the remaining cell voltage data except the target abnormal cell voltage data are sorted, and the remaining cell voltage mean data except the target abnormal cell voltage data are calculated to obtain the target abnormal cell voltage data sequence V A and the remaining monomer voltage mean value data sequence V B .

[0082] like Figure 3 As shown, in step S2, the target abnormal cell voltage data and the remaining cell voltage mean value data are smoothed.

[0083] Specifically, the target abnormal monomer voltage data marked in step S1 and the calculated remaining monomer voltage mean data are smoothed using a moving average smoothing algorithm, and the marked target abnormal monomer voltage data is smoothed as follows:

[0084]

[0085] Among them, V A 'The target abnormal monomer voltage data after smoothing, m is the moving average window size, k is the current data point index, j is the data point index variable, V A (j) is the target abnormal monomer voltage mean data obtained at index j;

[0086] The remaining monomer voltage mean data smoothing calculation is as follows:

[0087]

[0088] Among them, V B 'The remaining single-cell voltage mean data after smoothing, m is the moving average window size, k is the current data point index, j is the data point index variable, V A (j) is the mean voltage data of the remaining cells obtained at index j;

[0089] When using the moving average smoothing algorithm for smoothing, when the value of the window m is greater than the current data point index k, it means that the window exceeds the starting point of the existing data range, and the window size needs to be adjusted to adapt to the data range.

[0090] like Figure 3 As shown, in step S3, the SOC curve diagram is constructed for the battery module test, the SOC value corresponding to the abnormal single cell voltage data and the SOC value corresponding to the average data of the remaining single cell voltages are found, and the charging and discharging time points corresponding to the abnormal single cell voltage and the average single cell voltage reflected by the average of the remaining single cell voltages are obtained.

[0091] Specifically, the battery module is tested by a constant current charge and discharge method, the voltage data and time data of the single battery during the charge and discharge process are collected, the SOC value of each single battery at different times is calculated, the SOC value of each single battery at different times is collected to construct an SOC curve, and the high SOC interval and the low SOC interval are divided, the SOC value when the high SOC interval and the low SOC interval appear abnormal state is corrected, and the corrected SOC value is combined with the SOC value of each single battery at different times to further improve the SOC curve, wherein the high SOC interval and the low SOC interval correspond to 90%-100% and 0%-10% of the SOC respectively, and the abnormal state is divided into:

[0092] During the charging process, overcharging occurs in the high SOC range;

[0093] During the discharge process, over-discharge occurs in the low SOC range;

[0094] The high SOC interval and the low SOC interval have similar characteristics of peaks and valleys in the SOC curve. The high SOC interval (90%-100%) is similar to the area near the peak; the low SOC interval (0%-10%) is similar to the area near the valley. During charging, the high SOC interval may be overcharged, and during discharging, the low SOC interval may be over-discharged.

[0095] Find the charging and discharging time point according to the target abnormal cell voltage data smoothed in step S2 and the SOC value of the remaining cell voltage data;

[0096] The SOC value of each single battery at different times is calculated as:

[0097] Charging status:

[0098]

[0099] Wherein, SOC(t) is the state of charge of the battery at the charging time t, SOC(t0) is the state of charge at the start of charging, I is the constant current, t is the current charging process time, t0 is the charging start time, and C is the rated capacity of the battery;

[0100] Discharge status:

[0101]

[0102] Wherein, SOC(t) is the state of charge of the battery at the discharge time t, SOC(t0) is the state of charge at the start of discharge, I is the constant current, t is the current discharge process time, t0 is the discharge start time, and C is the rated capacity of the battery;

[0103] For the SOC value in abnormal state, the correction coefficient is introduced in the calculation process to correct the SOC value in abnormal state. The correction calculation is:

[0104] When overcharging occurs:

[0105] SOC' H (t) = SOC H (t)×K1

[0106] Among them, SOC' H (t) is the charge state at time t in the corrected charging process, SOC H (t) is the state of charge when overcharging occurs at time t during the uncorrected charging process, and K1 is the charging correction coefficient in the high SOC range;

[0107] When over discharge occurs:

[0108] SOC' L (t) = SOC L (t)×K2

[0109] Among them, SOC' L (t) is the charge state at time t in the discharge process after correction, SOC L (t) is the state of charge when over-discharge occurs at time t during the uncorrected discharge process, and K2 is the discharge correction coefficient in the low SOC range.

[0110] like Figure 3 As shown, in step S4, the charge and discharge quantity of the abnormal cell voltage and the average cell voltage is calculated.

[0111] Specifically, the SOC value of the abnormal cell voltage data and the SOC value of the average cell voltage data found by the SOC curve constructed in step S3 are used to calculate the charge and discharge power respectively by the SOC values ​​corresponding to the abnormal cell voltage data under charging conditions, and the charge time t3 and discharge time t4 determined by the average cell voltage, and the calculation is:

[0112] Abnormal charging state single cell voltage data:

[0113] Q1=I×(t1-t0)

[0114] Among them, Q1 is the charging power of the charging process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, I is the constant current, t0 is the starting time of the charging process, and t1 is the end time of the abnormal cell in the charging process;

[0115] The average voltage data of the remaining cells in the charging state:

[0116] Q2=I×(t3-t0)

[0117] Wherein, Q2 is the charging capacity during the charging process from the initial SOC value to the SOC value corresponding to the average cell voltage, I is the constant current, t0 is the starting time of the charging process, and t3 is the end time of the average cell in the charging process;

[0118] Abnormal discharge state single cell voltage data:

[0119] Q3=I×(t2-t0)

[0120] Among them, Q3 is the discharge power during the discharge process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, I is the constant current, t0 is the start time of the abnormal cell during the discharge process, and t2 is the end time of the abnormal cell during the discharge process;

[0121] The average voltage data of the remaining cells in the discharge state:

[0122] Q4=I×(t4-t0)

[0123] Among them, Q4 is the discharge power of the discharge process from the initial SOC value to the SOC value corresponding to the average cell voltage, I is the constant current, t0 is the start time of the average cell voltage in the discharge process, and t3 is the end time of the average cell in the discharge process.

[0124] like Figure 3 As shown, in step S5, the capacity deviation value is calculated according to the charge and discharge quantity of the abnormal single cell voltage and the average single cell voltage obtained in step S4, the capacity deviation degree is divided according to the calculation result, and the capacity deviation is corrected according to the deviation degree.

[0125] Specifically, the capacity deviation is calculated based on the abnormal single cell voltage data charge and discharge capacity calculated in step S4 and the remaining single cell voltage mean data, and is calculated as:

[0126] State of charge capacity deviation:

[0127]

[0128] Among them, ΔP1 is the capacity deviation degree during the charging process, Q1 is the charging power during the charging process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, and Q2 is the charging power during the charging process from the initial SOC value to the SOC value corresponding to the average cell voltage;

[0129] Discharge state capacity deviation:

[0130]

[0131] Among them, ΔP2 is the capacity deviation degree during the discharge process, Q3 is the discharge capacity during the discharge process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, and Q4 is the discharge capacity during the discharge process from the initial SOC value to the SOC value corresponding to the average cell voltage;

[0132] The calculated charge and discharge capacity deviation results are divided into capacity deviation levels. When the capacity deviation results reach the divided deviation levels, correction measures are taken to correct them. The settings are as follows:

[0133] The degree of deviation is divided into:

[0134] When the capacity deviation degree is between 0% and 5% and equal to 5%, it is a slight deviation;

[0135] When the capacity deviation degree is between 5% and 15% and equal to 15%, it is a moderate deviation;

[0136] When the degree of volume deviation is greater than 15%, it is considered a severe deviation;

[0137] The corrective measures are:

[0138] When the capacity deviation is slight, it is corrected by performing a replenishing discharge operation;

[0139] When the capacity deviation is moderate, the balanced charging control is combined with the replenishment discharge operation to make corrections;

[0140] When the capacity deviation is severe, stop using the battery and contact maintenance personnel for repair.

[0141] Specifically, the capacity deviation is calculated based on the calculated abnormal single cell voltage data charge and discharge capacity and the remaining single cell voltage average data, and the capacity deviation is corrected according to the degree of division as follows:

[0142] When the capacity deviation is slight, the correction is:

[0143] Get the current SOC value of the abnormal cell and the average SOC value of the other cells. Calculate the amount of power that needs to be replenished based on the difference between the two and the rated capacity of the battery. The preset rated capacity of the battery is C, and the current SOC value of the abnormal cell is SOCa , the average current SOC value of a single cell is SOC b , the amount of electricity that needs to be replenished is calculated as:

[0144] ΔQ=C×(SOC b -SOC a )

[0145] Among them, ΔQ is the amount of electricity required to be replenished, C is the rated capacity of the battery, and SOC a The current state of charge of the abnormal cell, SOC b is the current state of charge of the average monomer;

[0146] According to the calculation results, a small current is selected to supplement the abnormal monomer. After the supplement is completed, the battery is allowed to stand for a period of time to make the charge inside the battery evenly distributed. The battery module is discharged with a constant discharge current, and the discharge depth is controlled at 30%-50%. When the discharge reaches the set depth or the abnormal monomer voltage reaches the lower limit, the discharge is stopped, and then charged again, and the above supplement discharge cycle is repeated;

[0147] When the capacity deviation is moderate, the correction is:

[0148] Before the charging starts, the voltage and SOC value of each cell in the battery module are measured to calculate the charging demand of each cell, and more charging current is allocated to abnormal cells. The allocation calculation is:

[0149]

[0150] Among them, Q a is the abnormal monomer capacity, Q b is the average monomer capacity, Q c is the total capacity of the battery module, I a is the current allocated to the abnormal monomer, I d is the total charging current;

[0151] During the charging process, the charging process of the abnormal monomer is monitored. When the voltage of the abnormal monomer rises too fast, Ia is appropriately reduced, and the charging current of other monomers is increased. During discharge, a suitable discharge current is set. During the discharge process, the discharge process of each monomer is continuously monitored. If the voltage of the abnormal monomer drops too fast and approaches the lower limit, the discharge current distribution is adjusted to reduce the discharge current of the abnormal monomer, and the normal discharge of the remaining monomers is prioritized to prevent the abnormal monomer from over-discharging. When the discharge reaches the set discharge depth or a monomer in the battery module reaches the lower limit condition, the discharge is stopped, and then charging is performed again, and the above-mentioned charging and discharging cycle is repeated;

[0152] When the volume deviation is severe, the correction is:

[0153] Due to the serious deviation, the battery module should be stopped from use immediately and handled by professional maintenance personnel, including replacing the battery or repairing the insulation layer.

[0154] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0155] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and rules of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for estimating the deviation of capacity unevenness caused by voltage unevenness, characterized by: S1, obtaining target abnormal monomer voltage data and remaining monomer voltage data except the target abnormal monomer voltage data, and calculating the remaining monomer voltage mean data; S2, smoothing the target abnormal monomer voltage data and the remaining monomer voltage mean value data; S3, constructing an SOC curve diagram for the battery module test, finding the SOC value corresponding to the abnormal cell voltage data and the SOC value corresponding to the average cell voltage data of the remaining cells, and obtaining the charging and discharging time points corresponding to the abnormal cell voltage and the average cell voltage reflected by the average cell voltage of the remaining cells; S4, calculating the charge and discharge quantity of the abnormal cell voltage and the average cell voltage; S5. Calculate the capacity deviation value according to the charge and discharge quantity of the abnormal single cell voltage and the average single cell voltage obtained in step S4, divide the capacity deviation degree according to the calculation result, and correct the capacity deviation according to the deviation degree.

2. A method for estimating the deviation of capacity unevenness caused by voltage unevenness according to claim 1, characterized in that: In the step S1, the target abnormal cell voltage data and the remaining cell voltage data except the target abnormal cell voltage data are obtained, and the remaining cell voltage mean data are calculated as: A voltage sensor is installed in the battery module to measure the cell voltage data on each single cell, a measurement time is set to measure the voltage data, the cell voltage mean data is calculated, a voltage error threshold is set, the cell voltage mean data is combined with the cell voltage data to perform a voltage error threshold judgment, the judgment is that when the cell voltage data minus the cell voltage mean data is greater than the threshold, it is marked as target abnormal cell voltage data, the target abnormal cell voltage data is counted, and the remaining cell voltage data except the target abnormal cell voltage data are sorted, and the remaining cell voltage mean data except the target abnormal cell voltage data are calculated to obtain the target abnormal cell voltage data sequence and the remaining cell voltage mean data sequence.

3. The method for estimating the deviation of calculating the capacity unevenness abnormality caused by voltage unevenness according to claim 1, characterized in that: In step S2, the target abnormal cell voltage data and the remaining cell voltage mean value data are smoothed as follows: The target abnormal cell voltage data marked in step S1 and the calculated remaining cell voltage mean value data are smoothed using a moving average smoothing algorithm.

4. The method for estimating the deviation of calculating the capacity unevenness abnormality caused by voltage unevenness according to claim 1, characterized in that: In the step S3, the SOC curve diagram is constructed for the battery module test, the SOC value corresponding to the abnormal cell voltage data and the SOC value corresponding to the average cell voltage data of the remaining cells are found, and the charging and discharging time points corresponding to the abnormal cell voltage and the average cell voltage reflected by the average cell voltage of the remaining cells are obtained as follows: The battery module is tested by a constant current charge and discharge method, the voltage data and time data of the single cell during the charge and discharge process are collected, the SOC value of each single cell at different times is calculated, the SOC value of each single cell at different times is collected to construct an SOC curve graph, and the high SOC interval and the low SOC interval are divided, the SOC value when an abnormal state occurs in the high SOC interval and the low SOC interval is corrected, and the corrected SOC value is combined with the SOC value of each single cell at different times to further improve the SOC curve graph.

5. The method for estimating the deviation of calculating the capacity unevenness abnormality caused by voltage unevenness according to claim 1, characterized in that: The charge and discharge quantity of the abnormal cell voltage and the average cell voltage calculated in step S4 is: The SOC value of the abnormal single cell voltage data and the SOC value of the average voltage data of the remaining single cells found through the SOC curve diagram constructed in step S3, the charging and discharging times determined by the SOC values ​​corresponding to the abnormal single cell voltage data under charging conditions and the charging and discharging times determined by the average voltage data of the remaining single cells are used to calculate the charging and discharging capacities respectively.

6. The method for estimating the deviation of calculating the capacity unevenness abnormality caused by voltage unevenness according to claim 1, characterized in that: In step S5, the capacity deviation value is calculated based on the charge and discharge quantity of the abnormal single cell voltage and the average single cell voltage obtained in step S4, the capacity deviation degree is divided according to the calculation result, and the capacity deviation is corrected according to the deviation degree as follows: The capacity deviation is calculated based on the abnormal single cell voltage charge and discharge capacity calculated in step S4 and the average single cell voltage charge and discharge capacity. The calculated charge and discharge capacity deviation result is divided into capacity deviation degrees. When the capacity deviation result reaches the divided deviation degree, corrective measures are taken to correct it.

7. The method for estimating the deviation of calculating the capacity unevenness abnormality caused by voltage unevenness according to claim 3, characterized in that: The smoothing calculation is: Among them, V A 'The target abnormal monomer voltage data after smoothing, m is the moving average window size, k is the current data point index, j is the data point index variable, V A (j) is the target abnormal monomer voltage mean data obtained at index j; The remaining monomer voltage mean data smoothing calculation is as follows: Among them, V B 'The remaining single-cell voltage mean data after smoothing, m is the moving average window size, k is the current data point index, j is the data point index variable, V A (j) is the average voltage data of the remaining cells obtained at index j.

8. The method for estimating the deviation of calculating the capacity unevenness abnormality caused by voltage unevenness according to claim 6, characterized in that: The capacity deviation is calculated as: State of charge capacity deviation: Among them, ΔP1 is the capacity deviation degree during the charging process, Q1 is the charging power during the charging process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, and Q2 is the charging power during the charging process from the initial SOC value to the SOC value corresponding to the average cell voltage; Discharge state capacity deviation: Among them, ΔP2 is the capacity deviation degree during the discharge process, Q3 is the discharge capacity during the discharge process from the initial SOC value to the SOC value corresponding to the abnormal cell voltage, and Q4 is the discharge capacity during the discharge process from the initial SOC value to the SOC value corresponding to the average cell voltage.

9. The method for estimating the deviation of calculating the capacity unevenness abnormality caused by voltage unevenness according to claim 6, characterized in that: The degree of deviation is divided into: When the capacity deviation degree is between 0% and 5% and equal to 5%, it is a slight deviation; When the capacity deviation degree is between 5% and 15% and equal to 15%, it is a moderate deviation; When the capacity deviation is greater than 15%, it is considered a severe deviation.

10. The method for estimating the deviation of calculating the capacity unevenness abnormality caused by voltage unevenness according to claim 6, characterized in that: The capacity deviation correction is: When the capacity deviation is slight, it is corrected by performing a replenishing discharge operation; When the capacity deviation is moderate, the balanced charging control is combined with the replenishment discharge operation to make corrections; When the capacity deviation is severe, stop using the battery and contact maintenance personnel for repair.

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