Abnormal battery cell identification method, device and equipment of energy storage system, medium and product

Abstract

The invention provides an abnormal cell identification method and device of an energy storage system, equipment, a medium and a product. The method comprises the following steps: determining a first battery cell with high charging and low discharging phenomena in the energy storage system; obtaining a capacity influence value of the first battery cell according to the charging voltage and the discharging voltage of the first battery cell; the capacity influence value represents the capacity influence degree of the battery cell on the energy storage system when the battery cell is subjected to high-charge and low-discharge phenomena; and if the capacity influence value of the first battery cell exceeds a first preset threshold value, determining that the first battery cell is an abnormal battery cell. According to the scheme of the invention, the accuracy of an abnormal cell identification result is improved.

Description

Technical Field

[0001] The present application relates to the field of energy storage system analysis and control, and in particular to an abnormal battery cell identification method, device, equipment, medium and product for an energy storage system. Background Art

[0002] The energy storage system is composed of a number of battery cells, and the performance of the battery cells directly affects the performance of the entire energy storage system. The presence of abnormal battery cells may cause the performance of the energy storage system to deteriorate and fail to meet usage requirements. By identifying abnormal battery cells, they can be removed from the energy storage system in a timely manner, thereby optimizing the overall performance of the energy storage system; therefore, it is necessary to accurately identify abnormal battery cells in the energy storage system.

[0003] At present, in some solutions, whether a battery cell is an abnormal battery cell is determined by judging the change of the battery cell performance under the operating state; however, when using this method to identify abnormal batteries, the identification result is inaccurate, resulting in the inability to perform accurate and effective optimization processing for abnormal batteries. Summary of the invention

[0004] The present application provides a method, device, equipment, medium and product for identifying abnormal batteries in an energy storage system, which improves the accuracy of abnormal battery cell identification results in the energy storage system.

[0005] In a first aspect, the present application provides a method for identifying abnormal battery cells in an energy storage system, comprising: determining a first battery cell in the energy storage system that has a high-charge and low-discharge phenomenon; obtaining a capacity impact value of the first battery cell based on a charging voltage and a discharging voltage of the first battery cell; the capacity impact value represents the degree of impact of the battery cell on the capacity of the energy storage system when the high-charge and low-discharge phenomenon occurs; if the capacity impact value of the first battery cell exceeds a first preset threshold value, determining that the first battery cell is an abnormal battery cell.

[0006] In a possible implementation, determining the first battery cell in the energy storage system that is subjected to a high-charge and low-discharge phenomenon includes: obtaining a first charging voltage of each battery cell in the energy storage system at a charging terminal and a first discharging voltage of each battery cell at a discharging terminal; the charging terminal is a time when the voltage is last collected before the charging of the battery cell is completed; the discharging terminal is a time when the voltage is last collected before the discharging of the battery cell is completed; selecting a predetermined number of second battery cells from each battery cell in descending order according to the first charging voltage of each battery cell; selecting the same number of third battery cells from each battery cell in descending order according to the first discharging voltage of each battery cell; and determining the same battery cell between the second battery cell and the third battery cell as the first battery cell.

[0007] In a possible implementation, a predetermined number of second battery cells are selected from each battery cell in descending order based on the first charging voltage of each battery cell, including: sorting the first charging voltage of each battery cell in descending order to obtain a first sequence; and selecting a predetermined number of battery cells at the front of the second sequence as second battery cells.

[0008] In a possible implementation, according to the first discharge voltage of each battery cell, the same number of third battery cells are selected from each battery cell from small to large, including: sorting the first discharge voltage of each battery cell from small to large to obtain a second sequence; and selecting a predetermined number of battery cells in the front of the first sequence as the third battery cells.

[0009] In a possible implementation, after obtaining the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging in the energy storage system, it also includes: determining the maximum voltage among the first charging voltages of each battery cell and the minimum voltage among the first discharging voltages of each battery cell; selecting a predetermined number of second battery cells from each battery cell in descending order according to the first charging voltages of each battery cell, including: if the maximum voltage is greater than a second preset threshold value and the minimum voltage is less than a third preset threshold value, selecting a predetermined number of second battery cells from each battery cell in descending order according to the first charging voltages of each battery cell.

[0010] In a possible implementation, the method further includes: if the maximum voltage is not greater than a second preset threshold or the maximum voltage is not less than a third preset threshold, stopping abnormality identification.

[0011] In a possible implementation, the capacity impact value of the first battery cell is obtained according to the charging voltage and discharging voltage of the first battery cell, including: calculating the sum of the products of each first time difference between charging from the standard charging voltage to the first charging voltage of the first battery cell and the current at each moment, to obtain the charging capacity of the first battery cell; the standard charging voltage is obtained based on the charging voltage of all batteries in the energy storage system at the end of charging; the first time difference represents the time difference between any two moments between the moment of the standard charging voltage and the moment of the first charging voltage; calculating the sum of the products of each second time difference between discharging from the standard discharge voltage to the first discharge voltage of the first battery cell and the current at each moment, to obtain the discharge capacity of the first battery cell; the standard discharge voltage is obtained based on the discharge voltage of all batteries in the energy storage system at the end of discharge; the second time difference represents the time difference between any two moments between the moment of the standard discharge voltage and the moment of the first discharge voltage; obtaining the capacity impact value of the first battery cell according to the charging capacity of the first battery cell, the discharge capacity of the first battery cell and the rated capacity of the battery cell.

[0012] In a possible implementation, the capacity impact value of the first battery cell is obtained according to the first capacity of the first battery cell, the second capacity of the first battery cell and the rated capacity of the battery cell, including: calculating the sum of the first capacity of the first battery cell and the second capacity of the first battery cell to obtain a first result; calculating the ratio of the first result to the rated capacity of the battery cell to obtain the capacity impact value of the first battery cell.

[0013] In a possible implementation, the method further includes: calculating the median or quantile of the voltage of all the cells in the energy storage system at the end of charging to obtain a standard charging voltage; calculating the median or quantile of the voltage of all the cells in the energy storage system at the end of discharging to obtain a standard discharging voltage.

[0014] In a possible implementation, the method further includes: performing a balancing process on a fourth battery cell other than the first battery cell among the second battery cell and the third battery cell.

[0015] In a possible implementation, performing the balancing process includes: calculating a capacity balancing value of the fourth battery cell according to the first charging voltage or the first discharging voltage of the fourth battery cell; and performing balancing process on the fourth battery cell according to the capacity balancing value of the fourth battery cell.

[0016] In a possible implementation, the capacity balancing value of the fourth battery cell is calculated according to the first charging voltage or the first discharging voltage of the fourth battery cell, including: for the battery cell that is only charged high among the fourth battery cells, calculating the sum of the products of each first time difference between charging with a standard charging voltage to the first charging voltage of the battery cell and the current at each moment, to obtain the charging capacity of the battery cell; calculating the ratio of the charging capacity of the battery cell to the rated capacity of the battery cell, to obtain the capacity balancing value of the battery cell; for the battery cell that is only discharged low among the fourth battery cells, calculating the sum of the products of each second time difference between discharging with a standard discharge voltage to the first discharge voltage of the battery cell and the current at each moment, to obtain the discharge capacity of the battery cell; calculating the ratio of the discharge capacity of the battery cell to the rated capacity of the battery cell, to obtain the capacity balancing value of the battery cell.

[0017] In one possible implementation, the fourth battery cell is balanced according to the capacity balancing value of the fourth battery cell, including: for the battery cell that is only highly charged among the fourth battery cells, the battery cell is discharged according to the capacity balancing value of the battery cell until the battery capacity of the battery cell is equal to the second result; the second result represents the difference between the battery capacity of the battery cell before discharge and the capacity balancing value of the battery cell; for the battery cell that is only low charged among the fourth battery cell, the battery cell is recharged according to the capacity balancing value of the battery cell until the battery capacity of the battery cell is equal to the third result; the third result represents the sum of the battery capacity of the battery cell before recharging and the capacity balancing value of the battery cell.

[0018] In a possible implementation, the method further includes: if the capacity impact value of the first battery cell does not exceed a first preset threshold, determining that the first battery cell is not an abnormal battery cell.

[0019] In a second aspect, the present application provides an abnormal battery cell identification device for an energy storage system, including: a determination module, used to determine a first battery cell in the energy storage system that has a high-charge and low-discharge phenomenon; a processing module, used to obtain a capacity impact value of the first battery cell based on the charging voltage and the discharging voltage of the first battery cell; the capacity impact value represents the degree of impact of the battery cell on the capacity of the energy storage system when the high-charge and low-discharge phenomenon occurs; an identification module, used to determine that if the capacity impact value of the first battery cell exceeds a first preset threshold value, then the first battery cell is determined to be an abnormal battery cell.

[0020] In a third aspect, the present application provides an electronic device, including: a memory, a processor;

[0021] The memory stores computer-executable instructions;

[0022] The processor executes the computer-executable instructions stored in the memory, so that the processor executes the above first aspect and / or various possible implementations of the first aspect.

[0023] In a fourth aspect, the present application provides a computer-readable storage medium, in which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, they are used to implement the above first aspect and / or various possible implementations of the first aspect.

[0024] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the above first aspect and / or various possible implementations of the first aspect.

[0025] The abnormal battery cell identification method, device, equipment, medium and product of the energy storage system provided by the present application obtain the first battery cell in the energy storage system that has the phenomenon of high charging and low discharge; obtain the capacity influence value of the first battery cell according to the determined charging voltage and discharging voltage of the battery cell that has the phenomenon of high charging and low discharge; when the capacity influence value exceeds a preset threshold, the first battery cell is determined to be an abnormal battery cell; the scheme of the present application determines whether it is an abnormal battery cell according to the obtained capacity influence value, thereby improving the accuracy of abnormal battery cell identification; and the capacity influence value quantifies the degree of influence of the abnormal battery cell on the energy storage system, which can realize accurate judgment of the degree of influence of the abnormal battery cell on the energy storage system, and accurately and effectively perform corresponding optimization processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0027] Figure 1 A schematic diagram of a process for identifying abnormal cells in an energy storage system is exemplified;

[0028] Figure 2 A schematic diagram of a process for identifying abnormal cells in an energy storage system is exemplified;

[0029] Figure 3 A schematic diagram of a process for identifying abnormal cells in an energy storage system is exemplified;

[0030] Figure 4 A schematic diagram of a process for identifying abnormal cells in an energy storage system is exemplified;

[0031] Figure 5 A schematic diagram of a flow chart of a method for identifying abnormal cells in an energy storage system of the present application;

[0032] Figure 6 The schematic diagram of the structure of an abnormal battery cell identification device of an energy storage system is exemplarily shown;

[0033] Figure 7 A structural schematic diagram of an electronic device is exemplarily shown in FIG.

[0034] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0035] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise indicated. It should be understood that the terms used in this way can be interchangeable where appropriate, for example, they can be implemented in an order other than those given in the diagrams or descriptions of the embodiments of this application. The terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any of their variations are intended to cover but not exclude inclusion. For example, a product or device containing a series of components is not necessarily limited to those components clearly listed, but may include other components that are not clearly listed or inherent to these products or devices. The term "module" used in this application refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or a combination of hardware and / or software code that can perform functions related to the element.

[0037] The energy storage system is composed of a number of battery cells, and the performance of the battery cells directly affects the performance of the entire energy storage system. The presence of abnormal battery cells may cause the performance of the energy storage system to deteriorate and fail to meet usage requirements. By identifying abnormal battery cells, they can be removed from the energy storage system in a timely manner, thereby optimizing the overall performance of the energy storage system; therefore, it is necessary to accurately identify abnormal battery cells in the energy storage system.

[0038] At present, in some solutions, whether a battery cell is an abnormal battery cell is determined by judging the change of the battery cell performance under the operating state; however, when using this method to identify abnormal batteries, the identification result is inaccurate, resulting in the inability to perform accurate and effective optimization processing for abnormal batteries.

[0039] The technical solution provided by the present application is intended to solve the above technical problems of the prior art. The method, device, equipment, medium and product for identifying abnormal cells in an energy storage system provided by the present application obtain the first cell in the energy storage system that has undergone high-charging and low-discharging phenomena; obtain the capacity impact value of the first cell according to the determined charging voltage and discharging voltage of the cell that has undergone high-charging and low-discharging phenomena; when the capacity impact value exceeds a preset threshold, the first cell is determined to be an abnormal cell; the solution of the present application determines whether it is an abnormal cell according to the obtained capacity impact value, thereby improving the accuracy of identifying abnormal cells; and the capacity impact value quantifies the degree of influence of abnormal cells on the energy storage system, which can realize accurate judgment of the degree of influence of abnormal cells on the energy storage system, and accurately and effectively perform corresponding optimization processing.

[0040] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0041] Embodiment 1

[0042] Figure 1 A schematic diagram of a process for identifying abnormal cells in an energy storage system is shown as an example. Figure 1 As shown, the method includes:

[0043] Step 101, determining the first battery cell in the energy storage system that has a high-charge and low-discharge phenomenon;

[0044] Step 102: obtaining a capacity impact value of the first battery cell according to the charging voltage and the discharging voltage of the first battery cell; the capacity impact value represents the degree of influence of the battery cell on the capacity of the energy storage system when the battery cell is charged high and discharged low;

[0045] Step 103: If the capacity impact value exceeds a first preset threshold, the first battery cell is determined to be an abnormal battery cell.

[0046] In actual applications, the energy storage system contains multiple battery cells. The battery cell is the basic unit in the energy storage system. It is a chemical device composed of electrodes and electrolytes. It can store the obtained electrical energy in the form of chemical energy and can convert chemical energy into electrical energy. Specifically, first determine the first battery cell where the high-charge and low-discharge phenomenon occurs based on the operating status data of the battery cells in the energy storage system; in actual applications, the high-charge and low-discharge phenomenon refers to the process of charging, when a single battery cell first reaches the upper limit of voltage protection, the battery management system immediately cuts off the current to end charging, and the battery cell is "high-charged"; similarly, during the discharge process, when a single battery cell first reaches the lower limit of voltage protection, the battery management system also cuts off the current to end discharge, and the battery cell is "low-discharged"; therefore, high-charge and low-discharge actually refers to the two phenomena occurring in the same battery cell. The over-charging and under-discharging of a single cell is caused by the fact that the total capacity of the cell is lower than that of other cells; during the charging process, the voltage of the cell that has over-charging and under-discharging will rise rapidly and exceed the normal range; during the discharge process, the voltage of the cell will drop rapidly and be significantly lower than the normal level; the capacity of the cell that has over-charging and under-discharging will be significantly reduced, and the internal resistance will increase, affecting the charging and discharging efficiency of the cell, causing the cell to generate more heat during the charging and discharging process; at the same time, the self-discharge rate of the cell that has over-charging and under-discharging will be accelerated, and the cell will also lose power when it is stationary. Afterwards, the capacity impact value of the first cell that has over-charging and under-discharging is calculated based on the charging voltage and discharge voltage of the cell; wherein the capacity impact value represents the degree of impact of the cell that has over-charging and under-discharging on the capacity of the entire energy storage system. This example pre-sets a threshold value for the capacity impact value. When the capacity impact value of the cell that has over-charging and under-discharging on the entire energy storage system exceeds the preset threshold, the first cell is judged to be an abnormal cell. Subsequently, the identified abnormal cells can be optimized. This example does not specifically limit the optimization method. For example, new cells can be used to replace the identified abnormal cells. In this example, the capacity impact value of the cells that have high charge and low discharge in the energy storage system is calculated, and the cells whose capacity impact value exceeds the preset threshold are determined as abnormal cells, which improves the accuracy of the abnormal cell identification results. Subsequently, according to the identification results, corresponding optimization processing is performed to improve the effect of the optimization processing.

[0047] Furthermore, before identifying abnormal cells, it is necessary to first accurately determine the cells where the high-charge and low-discharge phenomena occur; accordingly, as an example, Figure 2 A schematic flow chart of a method for identifying abnormal cells in an energy storage system is exemplified; based on any example, step 101 includes:

[0048] Step 201, obtaining a first charging voltage of each battery cell at the end of charging and a first discharging voltage of each battery cell at the end of discharging in the energy storage system; the charging end time is the time when the voltage is last collected before the battery cell is charged; the discharging end time is the time when the voltage is last collected before the battery cell is discharged;

[0049] Step 202: Select a predetermined number of second battery cells from each battery cell in descending order according to the first charging voltage of each battery cell; select the same number of third battery cells from each battery cell in descending order according to the first discharging voltage of each battery cell;

[0050] Step 203: determine the same battery cell between the second battery cell and the third battery cell as the first battery cell.

[0051] Specifically, this example determines whether the battery cell has a high charge and low discharge phenomenon according to the charging voltage of each battery cell at the end of charging of the energy storage system and the discharging voltage of each battery cell at the end of discharging; the charging voltage and discharging voltage of the battery cell in the energy storage system are collected at the same time interval, and the charging end time indicates the time when the battery cell is last voltage collected before the end of charging; the discharging end time indicates the time when the battery cell is last voltage collected before the end of discharging. After obtaining the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging in the energy storage system, a preset number of second batteries are selected from them from large to small according to the collected first charging voltage; at the same time, a preset number of third batteries are selected from them from small to large according to the collected first discharging voltage; wherein the number of second batteries is the same as the number of third batteries; exemplary, the same battery cell in the second battery cell and the third battery cell is determined as the first battery cell. In this example, the battery cell that has a high charge and low discharge phenomenon is determined by the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging, thereby improving the accuracy of identifying the battery cell that has a high charge and low discharge phenomenon.

[0052] Furthermore, it is necessary to accurately select a preset number of second battery cells; accordingly, as an example, according to the first charging voltage of each battery cell, a predetermined number of second battery cells are selected from each battery cell from large to small, including:

[0053] Sorting the first charging voltages of the battery cells from large to small to obtain a first sequence;

[0054] The battery cells that are located in front of a predetermined number in the first sequence are selected as the second battery cells.

[0055] Exemplarily, a first sequence can be generated for the first charging voltage of each battery cell in descending order; then, a predetermined number of battery cells located at the front of the sequence are selected from the generated first sequence as the second battery cells. It should be noted that this example does not specifically limit the method of selecting the second battery cell; in one example, the 95% quantile of the first sequence can be selected to obtain a preset number of second battery cells; in another example, an unsupervised clustering method can be used to select the number of outlier battery cells as the second battery cell. In practical applications, the number of abnormal battery cells in the energy storage system accounts for a small proportion of the total number of battery cells in the energy storage system. Therefore, the 95% quantile of the first sequence can be selected to select the second battery cell, thereby improving the efficiency of identifying abnormal battery cells in the energy storage system. In this example, by generating a first sequence of the first charging voltage and selecting a preset number of battery cells from the first sequence as the second battery cell, the efficiency of identifying abnormal battery cells is improved.

[0056] Furthermore, the same number of third battery cells as the second battery cells needs to be selected; accordingly, as an example, the same number of third battery cells are selected from each battery cell from small to large according to the first discharge voltage of each battery cell, including:

[0057] The first discharge voltages of the battery cells are sorted from small to large to obtain a second sequence;

[0058] A predetermined number of battery cells in front of the second sequence are selected as the third battery cell.

[0059] Specifically, for the first discharge voltage of each battery cell, a second sequence is generated by sorting from small to large; a predetermined number of battery cells located at the front of the sequence are selected from the second sequence as the third battery cell. It should be noted that this example does not specifically limit the method of selecting the third battery cell; in one example, the 95% quantile of the second sequence can be selected to obtain a preset number of third battery cells; in another example, an unsupervised clustering method can be used to select the number of outlier batteries as the third battery cell. In this example, by generating a second sequence of the first discharge voltage and selecting a preset number of battery cells from the second sequence as the third battery cell, the efficiency of identifying abnormal batteries can be improved. Subsequently, the aforementioned first battery cell is determined based on the selected second and third batteries, and there is no need to identify abnormalities for all batteries in the energy storage system, thereby improving the efficiency of identifying abnormal batteries in the energy storage system.

[0060] Furthermore, after obtaining the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging, it is necessary to determine whether the charging voltage value and the discharging voltage value of each battery cell meet the preset threshold conditions to determine whether to perform abnormal identification. Accordingly, as an example, after obtaining the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging in the energy storage system, it also includes:

[0061] Determine a maximum voltage among the first charging voltages of the battery cells and a minimum voltage among the first discharging voltages of the battery cells;

[0062] According to the first charging voltage of each battery cell, a predetermined number of second battery cells are selected from each battery cell from large to small, including:

[0063] If the maximum voltage is greater than the second preset threshold and the minimum voltage is less than the third preset threshold, a predetermined number of second battery cells are selected from the battery cells in descending order according to the first charging voltages of the battery cells.

[0064] In practical applications, when it is necessary to identify abnormal cells in an energy storage system, it is first necessary to obtain the battery cluster-level data of the energy storage system under normal operating conditions; the battery cluster-level data usually includes the voltage, current, temperature, time and other information data of each cell; this example extracts features from the battery cluster-level data to obtain current, voltage and other data; the data after feature extraction is subjected to abnormal data detection and calibration; the calibrated abnormal data is then subjected to data preprocessing such as data cleaning and filling, and then the processed data is sorted by time to ensure that the data is strictly sorted in the order of collection time. Specifically, a battery cluster is composed of multiple battery modules (or cells) connected in series, parallel or series-parallel to form an independent battery assembly; the battery cluster data includes voltage, capacity, current, temperature, etc. After obtaining the battery-level cluster data, the relevant operating data of each cell in the energy storage system can be extracted. Further, when the sorted data is obtained, it is possible to determine which data in the preprocessed battery cluster-level data is data in the charging state and which is data in the discharging state based on the current value contained in the data; illustratively, the cell data corresponding to the current value less than 0 is the charging data, and the cell data corresponding to the current value greater than 0 is the discharging data; the charging data includes the charging voltage of the cell at the end of the charging state, and the discharging data includes the discharging voltage at the end of the discharging state. In this example, after obtaining the first charging voltage of each cell at the end of the charging state and the first discharging voltage of each cell at the end of the discharging state in the energy storage system, a second preset threshold value of the charging voltage and a third preset threshold value of the preset discharging voltage are preset; the maximum voltage of the first charging voltage of each cell is determined, and the minimum voltage of the first discharging voltage of each cell is determined; the determined maximum voltage is compared with the second preset threshold value; and the determined minimum voltage is compared with the third preset value; if the maximum voltage is greater than the second preset threshold value and the minimum voltage is less than the third preset threshold value, it is considered that the voltage of each cell meets the threshold condition of this example. Next, a predetermined number of second cells are selected from each cell in descending order according to the first charging voltage of each cell, and the subsequent abnormal battery identification process is executed. In this example, by preprocessing the acquired operation data of the cells of the energy storage system and comparing the maximum charging voltage and the minimum discharging voltage of each cell with the preset threshold conditions, the charging and discharging depth of the cell is ensured, and the accuracy of the abnormal cell identification result is further improved.

[0065] Further, when the aforementioned maximum voltage and minimum voltage do not meet the preset threshold conditions of the present application, corresponding processing is performed; accordingly, as an example, the method further includes:

[0066] If the maximum voltage is not greater than the second preset threshold or the minimum voltage is not less than the third preset threshold, abnormality identification is stopped.

[0067] Specifically, if the aforementioned maximum voltage is not greater than the second preset value, or the minimum voltage is not less than the third preset threshold value; it is considered that each battery cell in the energy storage system has not reached its respective charge and discharge depth, and abnormality identification is stopped. In combination with the above example, the second preset threshold is set to 5V, and the third preset voltage threshold is set to 2V; if the maximum voltage charged in each battery cell is not greater than 5V, it is considered that the battery cell has not reached the depth of charge set in this example; if the minimum voltage discharged in each battery cell is not less than 2V, it is considered that the battery cell has not reached the depth of discharge set in this example. At this time, the identification of abnormal batteries is stopped. In this example, the accuracy of the battery cell identification results is further improved by restricting the voltage identification conditions of abnormal batteries.

[0068] Further, after determining that the battery cell with high charge and low discharge phenomenon occurs, it is necessary to determine the capacity impact value of the battery cell with high charge and low discharge phenomenon, and judge whether the battery cell is an abnormal battery cell; accordingly, as an example, based on any example, Figure 3 A schematic flow chart of an abnormal battery cell identification method for an energy storage system is exemplarily shown; according to the charging voltage and discharging voltage of the first battery cell, a capacity impact value of the first battery cell is obtained, including:

[0069] Step 301, calculating the sum of the products of each first time difference between charging at a standard charging voltage and charging at a first charging voltage of a first battery cell and the current at each moment, to obtain the charging capacity of the first battery cell; the standard charging voltage is obtained based on the charging voltage of all batteries in the energy storage system at the end of charging; the first time difference represents the time difference between any two moments between the moment of the standard charging voltage and the moment of the first charging voltage;

[0070] Step 302, calculating the sum of the products of each second time difference between the standard discharge voltage and the first discharge voltage of the first battery cell and the current at each moment, to obtain the discharge capacity of the first battery cell; the standard discharge voltage is obtained based on the discharge voltage of all batteries in the energy storage system at the end of discharge; the second time difference represents the time difference between any two moments between the moment of the standard discharge voltage and the moment of the first discharge voltage;

[0071] Step 303: Obtain a capacity impact value of the first battery cell according to the charging capacity of the first battery cell, the discharging capacity of the first battery cell, and the rated capacity of the battery cell.

[0072] Specifically, the sum of the first time differences between charging with the standard charging voltage and the first charging voltage of the determined first battery cell and the product of the current at each moment is calculated to obtain the charging capacity of the first battery cell; wherein the standard charging voltage is obtained based on the charging voltage of all batteries in the energy storage system at the end of charging; the first time difference represents the time difference between any two moments between the moment of the standard charging voltage and the moment of the first charging voltage; in the process of identifying abnormal batteries, the charging voltage of each battery cell at the end of charging is sorted from high to low or from low to high, and the standard charging voltage is obtained from the charging voltages of all batteries at the end of charging; in one example, for the first battery cell that is charged high and discharged low, the first charging voltage of the first battery cell is 3.52V, and the standard charging voltage is 2.8V. The voltage is 3.48V; by simulating the charging process of the energy storage system, the charging capacity in the process of charging from 3.48V to 3.52V is calculated; assuming that the time corresponding to 3.48V is 10s, the charging current at this time is 3A; the next time is 15s, the corresponding current is 1A, and the corresponding voltage is 3.51V; the next time is 20s, the corresponding current is 2A, and the voltage is 3.52V; then the first first time difference is 5s, and the charging current of the first first time difference is 3A; the second first time difference is 5s, and the charging current of the second second time difference is 1A; then the charging capacity of the first battery cell is 5×3+5×1=20; the charging capacity value is obtained according to the unit conversion later, and it will not be specifically explained here. This example is only an exemplary explanation of obtaining the charging capacity. Therefore, according to the known voltage value and the corresponding current value and time value, the product of the time difference between different times and the corresponding current value can be calculated, and then the product of all the time differences and currents between the standard charging voltage and the first charging voltage can be accumulated to obtain the charging capacity of the first battery cell. Similarly, the sum of the products of the second time differences between the standard discharge voltage and the first discharge voltage of the first battery cell and the current at each moment is calculated to obtain the discharge capacity of the first battery cell; wherein the standard discharge voltage is obtained based on the discharge voltage of all batteries in the energy storage system at the end of charging; and the second time difference represents the time difference between any two moments between the moment of the standard discharge voltage and the moment of the first discharge voltage.Similarly, in the process of identifying abnormal cells, the discharge voltage of each cell at the end of discharge is sorted from high to low or from low to high, and the standard discharge voltage is obtained from the discharge voltage of all cells at the end of discharge. In one example, for the first cell where high charge and low discharge occur, the first discharge voltage of the first cell is 3.05V, and the standard charge voltage is 3.35V. By simulating the discharge process of the energy storage system, the discharge capacity in the process of discharging from 3.35V to 3.05V is calculated. Assuming that the time corresponding to 3.35V is 10s, this The discharge current at the time is 2A; the next moment is 15s, the corresponding current is 3A, and the corresponding voltage is 3.23V; the next moment is 20s, the corresponding current is 1A, and the voltage is 3.05V; then the first first time difference is 5s, and the discharge current of the first first time difference is 2A; the second first time difference is 5s, and the charging current of the second second time difference is 3A; then the discharge capacity of the first battery cell is 5×2+5×3=25; the discharge capacity value is obtained according to the unit conversion later, and it will not be elaborated in detail. This example is only an exemplary explanation of obtaining the discharge capacity. Therefore, according to the known discharge voltage value and the corresponding current value and time value, the product of the time difference between different moments and the corresponding current value can be calculated, and then the product of all the time differences and currents between the standard discharge voltage and the first charging voltage can be accumulated to obtain the discharge capacity of the first battery cell. The capacity impact value of the first battery cell is obtained based on the obtained charging capacity of the first battery cell, the discharging capacity of the first battery cell, and the rated capacity of the battery cell; subsequently, whether the battery cell is an abnormal battery cell is determined based on the obtained capacity impact value, and corresponding abnormal processing is performed. In this example, the capacity impact value of the battery cell is obtained by calculating the first capacity and the second capacity, thereby improving the accuracy of the capacity impact value calculation.

[0073] Furthermore, it is necessary to calculate the capacity impact value according to the aforementioned first capacity and second capacity and the rated capacity of the battery cell; accordingly, as an example, according to the first capacity of the first battery cell, the second capacity of the first battery cell and the rated capacity of the battery cell, the capacity impact value of the first battery cell is obtained, including:

[0074] Calculating the sum of the charging capacity of the first battery cell and the discharging capacity of the first battery cell to obtain a first result;

[0075] The ratio of the first result to the rated capacity of the battery cell is calculated to obtain a capacity impact value of the first battery cell.

[0076] Specifically, according to the charging capacity of the first battery cell and the discharging capacity of the first battery cell obtained above, the sum of the charging capacity of the first battery cell and the discharging capacity of the first battery cell is calculated to obtain a first result; then, the ratio of the first result to the rated capacity of the battery cell is calculated to obtain the capacity impact value of the first battery cell. In practical applications, the rated capacity of a battery cell is an important parameter that describes the capacity of a battery cell to store electricity, indicating the minimum amount of electricity that a specified battery cell should be able to discharge under certain discharge conditions (such as discharge current and temperature, etc.). The capacity impact value obtained according to the ratio of the sum of the charging capacity of the first battery cell and the discharging capacity of the first battery cell to the rated capacity of the battery cell characterizes the degree of influence of the high charging and low discharging states on the capacity of the energy storage system; the accuracy of the calculation of the capacity impact value is improved.

[0077] Specifically, when it is necessary to accurately calculate the charging capacity and discharging capacity of the first battery cell, it is necessary to obtain an accurate standard charging voltage and a standard discharging voltage; accordingly, as an example, the method further includes:

[0078] Calculate the median or quantile of the voltage of all cells in the energy storage system at the end of charging to obtain the standard charging voltage;

[0079] Calculate the median or quantile of the voltage of all cells in the energy storage system at the end of discharge to obtain the standard discharge voltage.

[0080] Specifically, the aforementioned preset standard charging voltage and standard discharging voltage are obtained based on the charging voltage and discharging voltage of all cells in the energy storage system; in one example, the standard charging voltage can be determined by calculating the median of all charging voltages by calculating the charging voltage of all cells in the energy storage system at the end of charging; or the standard charging voltage can be determined according to the 95% quantile of the charging voltage of all cells at the end of charging. In another example, the standard discharge voltage can be determined by calculating the median of all discharge voltages by calculating the discharge voltage of all cells in the energy storage system at the end of discharge; or the standard discharge voltage can be determined according to the 95% quantile of the discharge voltage of all cells at the end of discharge; it should be noted that this example does not limit the specific method for determining the standard charging voltage and the standard discharge voltage. In this example, the standard charging voltage and the standard discharge voltage are determined according to the median or quantile of the charging voltage of all cells and the median or quantile of the discharge voltage; the accuracy of determining the standard charging voltage and the standard discharge voltage is improved.

[0081] Further, after the abnormal cells are identified, equalization processing is performed on some of the cells that are overcharged or undercharged; accordingly, as an example, the method further includes:

[0082] The equalization process is performed on a fourth cell other than the first cell among the second cell and the third cell.

[0083] For the aforementioned second and third cells that do not belong to the same cell, that is, the cells other than the first cell, balancing is performed. In practical applications, balancing the cells means using specific technologies and means to ensure that each single cell in the battery pack is as consistent as possible in terms of voltage, capacity and operating status; balancing can avoid the performance degradation of the entire battery pack due to the degradation of the performance of individual cells; at the same time, balancing can reduce the voltage and capacity differences between cells, reduce the internal resistance of the battery, and thus extend the service life of the cells; balancing can also prevent overcharging or over-discharging of cells, and reduce the risk of safety hazards such as thermal runaway. In this example, by performing balancing on cells that are overcharged or undercharged, the charge and discharge capacity of the entire energy storage system is improved, and the performance of the energy storage system is optimized.

[0084] Further, performing equalization processing includes:

[0085] Calculating a capacity balancing value of the fourth battery cell according to the first charging voltage or the first discharging voltage of the fourth battery cell;

[0086] The fourth battery cell is subjected to equalization processing according to the capacity equalization value of the fourth battery cell.

[0087] Specifically, to perform balancing processing on the fourth battery cell, it is necessary to calculate the capacity balancing value of the fourth battery cell according to the first charging voltage or the first discharging voltage of the fourth battery cell; and to perform balancing processing on the fourth battery cell according to the fourth capacity balancing value. In this example, the fourth battery cell is balancing processed according to the capacity balancing value of the fourth battery cell, thereby improving the effect of balancing processing.

[0088] Furthermore, when performing the equalization process, it is necessary to accurately calculate the capacity equalization value corresponding to each battery cell; accordingly, as an example, according to the first charging voltage or the first discharging voltage of the fourth battery cell, the capacity equalization value of the fourth battery cell is calculated, including:

[0089] For the fourth battery cell that is only charged high, the sum of the products of the first time differences between charging at the standard charging voltage and the first charging voltage of the battery cell and the current at each time is calculated to obtain the charging capacity of the battery cell; the ratio of the charging capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell;

[0090] For the fourth battery cell where only discharge occurs, calculate the sum of the products of the second time differences between the discharge from the standard discharge voltage to the first discharge voltage of the battery cell and the current at each moment to obtain the discharge capacity of the battery cell; calculate the ratio of the discharge capacity of the battery cell to the rated capacity of the battery cell to obtain the capacity balance value of the battery cell.

[0091] Specifically, for the fourth battery cell that only experiences high charging, the sum of the products of the first time differences between charging with the standard charging voltage and the first charging voltage of the battery cell and the current at each moment is calculated to obtain the charging capacity of the battery cell; the ratio of the charging capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell; correspondingly, for the fourth battery cell that only experiences low charging, the sum of the products of the second time differences between discharging with the standard discharge voltage and the first discharge voltage of the battery cell and the current at each moment is calculated to obtain the discharge capacity of the battery cell; the ratio of the discharge capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell. Exemplarily, the calculation of the charging capacity of a battery cell that has only been charged up is consistent with the calculation method for calculating the charging capacity of the first battery cell described above; based on the known voltage value of the first charging voltage of the battery cell that has been charged up and the corresponding current value and time value, the product of the time difference between different times and the corresponding current value is calculated, and then the product of all time differences between charging from the standard charging voltage to the first charging voltage of the battery cell and the current are accumulated to obtain the charging capacity of the battery cell; the ratio of the charging capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell; similarly, the calculation of the discharge capacity of a battery cell that has only been discharged is consistent with the calculation method for calculating the discharge capacity of the first battery cell described above; based on the known voltage value of the first discharge voltage of the battery cell that has been discharged and the corresponding current value and time value, the product of the time difference between different times and the corresponding current value is calculated, and then the product of all time differences between discharging from the standard discharge voltage to the first discharge voltage of the battery cell and the current are accumulated to obtain the discharge capacity of the battery cell; the ratio of the discharge capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell. In this example, by calculating the charging capacity or discharging capacity of the battery cell that is overcharged or undercharged, the capacity balancing value of the corresponding battery cell is calculated, thereby improving the accuracy of the calculation result of the capacity balancing value.

[0092] After the capacity balancing value is obtained, the capacity balancing process is performed on the fourth battery cell; accordingly, as an example, Figure 4 A schematic flow chart of an abnormal cell identification method of an energy storage system is exemplarily shown, wherein the fourth cell is subjected to equalization processing according to the capacity equalization value of the fourth cell, including:

[0093] Step 401: for the battery cell that is only highly charged in the fourth battery cell, discharge the battery cell according to the capacity balance value of the battery cell until the battery capacity of the battery cell is equal to the second result; the second result represents the difference between the battery capacity of the battery cell before discharge and the capacity balance value of the battery cell;

[0094] Step 402: for the battery cell that has only been discharged in the fourth battery cell, the battery cell is recharged according to the capacity balance value of the battery cell until the battery capacity of the battery cell is equal to the third result; the third result represents the sum of the battery capacity before recharging and the capacity balance value of the battery cell.

[0095] Specifically, after obtaining the capacity balancing value of the fourth battery cell, for the battery cell that is overcharged, the battery cell is discharged according to the obtained capacity balancing value of the battery cell, and the battery cell capacity of the battery cell is discharged until it is equal to the second result; wherein the second result represents the difference between the battery cell capacity before discharge and the capacity balancing value of the battery cell, that is, the battery cell capacity before balancing (before discharge) minus the calculated capacity balancing value. Exemplarily, according to the capacity balancing value, the battery cell capacity before discharge is discharged to a battery cell capacity equal to the capacity balancing value of the battery cell, and after the capacity equal to the capacity balancing value is discharged, the battery cell capacity after balancing can be obtained; for the battery cell that is undercharged, according to the obtained capacity balancing value of the battery cell, the battery cell is supplemented to a battery cell capacity equal to the third result; wherein the third result represents the sum of the battery cell capacity before supplementation and the capacity balancing value of the battery cell, that is, the battery cell capacity before balancing (before supplementation) plus the calculated capacity balancing value. Exemplarily, according to the capacity balancing value, the battery cell is supplemented with electricity, and the battery cell capacity equal to the capacity balancing value of the battery cell is supplemented. After the battery cell is supplemented with electricity, the balanced battery cell capacity can be obtained. This example does not limit the balancing method of the battery cell; in practical applications, when the battery cell is balanced, the main balancing methods used include active balancing and passive balancing; active balancing is a technology that achieves balancing between battery cells by energy transfer. It uses a specific circuit structure and control strategy to supplement the power in the high-energy battery cell to the low-energy battery cell to achieve the optimization of the overall performance of the battery pack. Passive balancing is a method of dissipating extra energy through an external resistor or discharge device, which aims to solve the problem of inconsistent charge state and voltage between single cells in a battery pack. Active balancing is balanced through a circuit structure composed of a circuit and a control chip, and an energy transfer device is used to transfer energy from a high-energy single cell to a low-energy single cell. Passive balancing dissipates extra energy through an external resistor or discharge device to achieve the purpose of balancing. In this example, by performing balancing processing on the battery cells according to the capacity balancing values ​​of the battery cells, the balancing effect on the battery cells is improved.

[0096] Further, when the determined capacity impact value of the first battery cell exceeds the threshold, it is considered that there is no abnormal battery cell in the energy storage system; accordingly, as an example, the method further includes:

[0097] If the capacity impact value of the first battery cell does not exceed the first preset threshold, it is determined that the first battery cell is not an abnormal battery cell.

[0098] Specifically, after the first battery cell is determined, its capacity impact value is calculated, and the obtained capacity impact value of the first battery cell is compared with the first preset value; if the capacity impact value of the battery cell does not exceed the first preset value, the first battery cell is determined not to be an abnormal battery cell. In this example, when a battery cell in the energy storage system is overcharged and undercharged, it is necessary to determine whether it is an abnormal battery cell based on the actual impact value of the battery cell being overcharged and undercharged; to avoid the situation where a battery cell is still determined to be an abnormal battery cell even though it is overcharged and undercharged but its impact on the energy storage system does not exceed the preset threshold. This improves the accuracy of identifying abnormal batteries in the energy storage system.

[0099] In one example, Figure 5 Schematic diagram of the process of the abnormal battery cell identification method of the energy storage system of the present application, such as Figure 5 As shown, when it is necessary to identify abnormal battery cells, first obtain the battery cluster level data under the operating state of the energy storage system, and then pre-process the battery cluster level data to obtain the processed data; next, determine whether the maximum voltage of the battery cell at the end of charging and the minimum voltage at the end of discharging in the processed data meet the threshold conditions. If not, the identification ends; if so, select the same preset number of second battery cells and third battery cells according to the first charging voltage and the first discharging voltage of each battery cell, and determine the identical battery cells in the second battery cells and the third battery cells. If there are no identical battery cells, determine whether there are battery cells that need to be balanced. If not, stop the identification. If so, perform the balanced processing; if there are identical battery cells, identify whether the battery cell is an abnormal battery cell. If an abnormality is identified, perform the corresponding optimization processing. It should be noted that Figure 5 This is only a flow chart of a single identification. After one identification is completed, the present application executes the identification process of abnormal cells in the energy storage system again until no abnormal cells are found in the energy storage system and no cells need to be balanced, then the identification ends.

[0100] In the abnormal battery cell identification method of the energy storage system provided in the present embodiment, the first battery cell in the energy storage system that has the phenomenon of high charging and low discharge is obtained; the capacity influence value of the first battery cell is obtained according to the determined charging voltage and discharging voltage of the battery cell that has the phenomenon of high charging and low discharge; when the capacity influence value exceeds a preset threshold value, the first battery cell is determined to be an abnormal battery cell; the scheme of the present application determines whether it is an abnormal battery cell according to the obtained capacity influence value, thereby improving the accuracy of abnormal battery cell identification; and the capacity influence value quantifies the degree of influence of the abnormal battery cell on the energy storage system, which can realize accurate judgment of the degree of influence of the abnormal battery cell on the energy storage system, and accurately and effectively perform corresponding optimization processing.

[0101] Embodiment 2

[0102] Figure 6The schematic diagram of the structure of an abnormal battery cell identification device of an energy storage system is shown as an example; Figure 6 As shown, the device comprises:

[0103] A determination module 21, used to determine the first battery cell in the energy storage system where a high-charge and low-discharge phenomenon occurs;

[0104] The processing module 22 is used to obtain a capacity impact value of the first battery cell according to the charging voltage and the discharging voltage of the first battery cell; the capacity impact value represents the degree of influence of the battery cell on the capacity of the energy storage system when the battery cell is charged high and discharged low;

[0105] The identification module 23 is used to determine that if the capacity impact value of the first battery cell exceeds a first preset threshold value, the first battery cell is determined to be an abnormal battery cell.

[0106] In practical applications, the energy storage system contains multiple cells. The cell is the basic unit in the energy storage system. It is a chemical device composed of electrodes and electrolytes. It can store the obtained electrical energy in the form of chemical energy and can convert chemical energy into electrical energy. Specifically, first, according to the operating status data of the cells in the energy storage system, the first cell where the high-charge and low-discharge phenomenon occurs is determined; in practical applications, the high-charge and low-discharge phenomenon refers to the fact that during the charging process, when a single cell first reaches the upper limit of the voltage protection, the battery management system cuts off the current to end the charging, and the cell is "high-charged"; similarly, during the discharge process, when a single cell first reaches the lower limit of the voltage protection, the battery management system also cuts off the current to end the discharge, and the cell is "low-discharged"; therefore, high-charge and low-discharge actually refers to the fact that both phenomena occur in the same cell. Afterwards, the capacity impact value of the first cell where the high-charge and low-discharge phenomenon occurs is calculated based on the charging voltage and discharge voltage of the cell; wherein, the capacity impact value represents the degree of influence of the cell where the high-charge and low-discharge phenomenon occurs on the capacity of the entire energy storage system. This example pre-sets a threshold for the capacity impact value. When the capacity impact value of the battery cell that has been overcharged and undercharged on the entire energy storage system exceeds the preset threshold, the first battery cell is judged to be an abnormal battery cell. Subsequently, the identified abnormal battery cells can be optimized. This example does not specifically limit the method of optimization processing; for example, the identified abnormal battery cells can be replaced with new battery cells. In this example, the accuracy of the abnormal battery cell identification results is improved by calculating the capacity impact value of the battery cell that has been overcharged and undercharged in the energy storage system, and judging the battery cell whose capacity impact value exceeds the preset threshold as an abnormal battery cell; subsequently, according to the identification results, corresponding optimization processing is performed to improve the effect of the optimization processing.

[0107] Furthermore, before identifying abnormal cells, it is necessary to first accurately determine the cells where the over-charge and under-discharge phenomena occur; accordingly, as an example, the determination module 21 is used to:

[0108] Obtain the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging in the energy storage system; the charging end time is the time when the voltage is last collected before the battery cell is charged; the discharging end time is the time when the voltage is last collected before the battery cell is discharged;

[0109] According to the first charging voltage of each battery cell, a predetermined number of second battery cells are selected from each battery cell in a descending order; according to the first discharging voltage of each battery cell, the same number of third battery cells are selected from each battery cell in a descending order;

[0110] The same battery cell between the second battery cell and the third battery cell is determined as the first battery cell.

[0111] Specifically, this example determines whether the cell has a high charge and low discharge phenomenon according to the charging voltage of each cell at the end of charging and the discharging voltage of each cell at the end of discharging in the energy storage system; the charging voltage and discharging voltage of the cell in the energy storage system are collected at the same time interval, and the charging end time indicates the time when the cell voltage is collected for the last time before the charging is completed; the discharging end time indicates the time when the cell voltage is collected for the last time before the discharging is completed. After obtaining the first charging voltage of each cell at the end of charging and the first discharging voltage of each cell at the end of discharging in the energy storage system, a preset number of second cells are selected from the collected first charging voltage from large to small; at the same time, a preset number of third cells are selected from the collected first discharging voltage from small to large; wherein the number of second cells is the same as the number of third cells; exemplary, the same cell in the second cell and the third cell is determined as the first cell. In this example, the cell that has a high charge and low discharge phenomenon is determined by the first charging voltage of each cell at the end of charging and the first discharging voltage of each cell at the end of discharging, thereby improving the accuracy of identifying the cell that has a high charge and low discharge.

[0112] Furthermore, it is necessary to accurately select a preset number of second battery cells; accordingly, as an example, according to the first charging voltage of each battery cell, a predetermined number of second battery cells are selected from each battery cell from large to small, including:

[0113] Sorting the first charging voltages of the battery cells from large to small to obtain a first sequence;

[0114] The battery cells that are located in front of a predetermined number in the first sequence are selected as the second battery cells.

[0115] Exemplarily, a first sequence can be generated for the first charging voltage of each battery cell in descending order; then, a predetermined number of battery cells located at the front of the sequence are selected from the generated first sequence as the second battery cells. It should be noted that this example does not specifically limit the method of selecting the second battery cell; in one example, the 95% quantile of the first sequence can be selected to obtain a preset number of second battery cells; in another example, an unsupervised clustering method can be used to select the number of outlier battery cells as the second battery cell. In practical applications, the number of abnormal battery cells in the energy storage system accounts for a small proportion of the total number of battery cells in the energy storage system. Therefore, the 95% quantile of the first sequence can be selected to select the second battery cell, thereby improving the efficiency of identifying abnormal battery cells in the energy storage system. In this example, by generating a first sequence of the first charging voltage and selecting a preset number of battery cells from the first sequence as the second battery cell, the efficiency of identifying abnormal battery cells is improved.

[0116] Furthermore, the same number of third battery cells as the second battery cells needs to be selected; accordingly, as an example, the same number of third battery cells are selected from each battery cell from small to large according to the first discharge voltage of each battery cell, including:

[0117] The first discharge voltages of the battery cells are sorted from small to large to obtain a second sequence;

[0118] A predetermined number of battery cells in front of the second sequence are selected as the third battery cell.

[0119] Specifically, for the first discharge voltage of each battery cell, a second sequence is generated by sorting from small to large; a predetermined number of battery cells located at the front of the sequence are selected from the second sequence as the third battery cell. It should be noted that this example does not specifically limit the method of selecting the third battery cell; in one example, the 95% quantile of the second sequence can be selected to obtain a preset number of third battery cells; in another example, an unsupervised clustering method can be used to select the number of outlier batteries as the third battery cell. In this example, by generating a second sequence of the first discharge voltage and selecting a preset number of battery cells from the second sequence as the third battery cell, the efficiency of identifying abnormal batteries can be improved. Subsequently, the aforementioned first battery cell is determined based on the selected second and third batteries, and there is no need to identify abnormalities for all batteries in the energy storage system, thereby improving the efficiency of identifying abnormal batteries in the energy storage system.

[0120] Furthermore, after obtaining the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging, it is necessary to determine whether the charging voltage value and the discharging voltage value of each battery cell meet the preset threshold conditions to determine whether to perform abnormal identification. Accordingly, as an example, after obtaining the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging in the energy storage system, it also includes:

[0121] Determine a maximum voltage among the first charging voltages of the battery cells and a minimum voltage among the first discharging voltages of the battery cells;

[0122] According to the first charging voltage of each battery cell, a predetermined number of second battery cells are selected from each battery cell from large to small, including:

[0123] If the maximum voltage is greater than the second preset threshold and the minimum voltage is less than the third preset threshold, a predetermined number of second battery cells are selected from the battery cells in descending order according to the first charging voltages of the battery cells.

[0124] In this example, after obtaining the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging in the energy storage system, a second preset threshold value of the charging voltage and a third preset threshold value of the preset discharging voltage are preset; the maximum voltage of the first charging voltage of each battery cell is determined, and the minimum voltage of the first discharging voltage of each battery cell is determined; the determined maximum voltage is compared with the second preset threshold value; and the determined minimum voltage is compared with the third preset value; if the maximum voltage is greater than the second preset threshold value and the minimum voltage is less than the third preset threshold value, it is considered that the voltage of each battery cell meets the threshold condition of this example. Next, according to the first charging voltage of each battery cell, a predetermined number of second batteries are selected from each battery cell from large to small; and the subsequent abnormal battery identification process is executed. In this example, by preprocessing the operation data of the battery cells of the energy storage system obtained, and comparing the maximum charging voltage and the minimum discharging voltage of each battery cell with the preset threshold conditions, the charging and discharging depth of the battery cell is guaranteed, and the accuracy of the abnormal battery cell identification result is further improved.

[0125] Further, when the aforementioned maximum voltage and minimum voltage do not meet the preset threshold conditions of the present application, corresponding processing is performed; accordingly, as an example, the identification module 23 is also used for:

[0126] If the maximum voltage is not greater than the second preset threshold or the minimum voltage is not less than the third preset threshold, abnormality identification is stopped.

[0127] Specifically, if the aforementioned maximum voltage is not greater than the second preset value, or the minimum voltage is not less than the third preset threshold value, it is considered that each battery cell in the energy storage system has not reached its respective charge and discharge depth, and abnormal identification is stopped. In this example, by limiting the voltage identification conditions of abnormal batteries, the accuracy of the battery cell identification results is further improved.

[0128] Further, after determining that the battery cell with the high-charge and low-discharge phenomenon has occurred, it is necessary to determine the capacity impact value of the battery cell with the high-charge and low-discharge phenomenon to determine whether the battery cell is an abnormal battery cell; accordingly, as an example, the processing module 22 is used to:

[0129] The sum of the products of the first time differences between charging the standard charging voltage to the first charging voltage of the first battery cell and the current at each moment is calculated to obtain the charging capacity of the first battery cell; the standard charging voltage is obtained based on the charging voltage of all batteries in the energy storage system at the end of charging; the first time difference represents the time difference between any two moments between the moment of the standard charging voltage and the moment of the first charging voltage;

[0130] The sum of the products of the second time differences between the discharge of the standard discharge voltage to the first discharge voltage of the first battery cell and the current at each moment is calculated to obtain the discharge capacity of the first battery cell; the standard discharge voltage is obtained based on the discharge voltage of all batteries in the energy storage system at the end of discharge; the second time difference represents the time difference between any two moments between the moment of the standard discharge voltage and the moment of the first discharge voltage;

[0131] A capacity impact value of the first battery cell is obtained according to the charging capacity of the first battery cell, the discharging capacity of the first battery cell, and the rated capacity of the battery cell.

[0132] Specifically, the sum of the products of the first time differences and the current at each moment between charging from the standard charging voltage to the determined first charging voltage of the first battery cell is calculated to obtain the charging capacity of the first battery cell; wherein the standard charging voltage is obtained based on the charging voltages of all batteries in the energy storage system at the charging end; the first time difference represents the time difference between any two moments between the moment of the standard charging voltage and the moment of the first charging voltage; in the process of identifying abnormal batteries, the charging voltages of each battery cell at the charging end are sorted from high to low or from low to high, and the standard charging voltage is obtained from the charging voltages of all batteries at the charging end; in an example, for the first battery cell that is charged high and discharged low, the first charging voltage of the first battery cell is 3.52V, and the standard charging voltage is 1.5V. The voltage of the battery is 3.48V; by simulating the charging process of the energy storage system, the charging capacity in the process of charging from 3.48V to 3.52V is calculated; assuming that the time corresponding to 3.48V is 10s, the charging current at this time is 3A; the next time is 15s, the corresponding current is 1A, and the corresponding voltage is 3.51V; the next time is 20s, the corresponding current is 2A, and the voltage is 3.52V; then the first time difference is 5s, and the charging current of the first time difference is 3A; the second time difference is 5s, and the charging current of the second time difference is 1A; then the charging capacity of the first battery cell is 5×3+5×1=20; the charging capacity value is obtained according to the unit conversion later, and it will not be specifically explained here. This example is only an exemplary explanation of obtaining the charging capacity. Therefore, according to the known voltage value and the corresponding current value and time value, the product of the time difference between different times and the corresponding current value can be calculated, and then the product of all the time differences and currents between the standard charging voltage and the first charging voltage can be accumulated to obtain the charging capacity of the first battery cell. Similarly, the sum of the products of the second time differences between the standard discharge voltage and the first discharge voltage of the first battery cell and the current at each moment is calculated to obtain the discharge capacity of the first battery cell; wherein the standard discharge voltage is obtained based on the discharge voltage of all batteries in the energy storage system at the end of charging; and the second time difference represents the time difference between any two moments between the moment of the standard discharge voltage and the moment of the first discharge voltage.Similarly, in the process of identifying abnormal cells, the discharge voltage of each cell at the end of discharge is sorted from high to low or from low to high, and the standard discharge voltage is obtained from the discharge voltage of all cells at the end of discharge. In one example, for the first cell where high charge and low discharge occur, the first discharge voltage of the first cell is 3.05V, and the standard charge voltage is 3.35V. By simulating the discharge process of the energy storage system, the discharge capacity in the process of discharging from 3.35V to 3.05V is calculated. Assuming that the time corresponding to 3.35V is 10s, this The discharge current at the time is 2A; the next moment is 15s, the corresponding current is 3A, and the corresponding voltage is 3.23V; the next moment is 20s, the corresponding current is 1A, and the voltage is 3.05V; then the first second time difference is 5s, and the discharge current of the first second time difference is 2A; the second second time difference is 5s, and the charging current of the second second time difference is 3A; then the discharge capacity of the first battery cell is 5×2+5×3=25; the discharge capacity value is obtained according to the unit conversion later, and it will not be elaborated in detail. This example is only an exemplary explanation of obtaining the discharge capacity. Therefore, according to the known discharge voltage value and the corresponding current value and time value, the product of the time difference between different moments and the corresponding current value can be calculated, and then the product of the time difference and the current in all time intervals between the standard discharge voltage and the first charging voltage can be accumulated to obtain the discharge capacity of the first battery cell. The capacity impact value of the first battery cell is obtained based on the obtained charging capacity of the first battery cell, the discharging capacity of the first battery cell, and the rated capacity of the battery cell; subsequently, whether the battery cell is an abnormal battery cell is determined based on the obtained capacity impact value, and corresponding abnormal processing is performed. In this example, the capacity impact value of the battery cell is obtained by calculating the first capacity and the second capacity, thereby improving the accuracy of the capacity impact value calculation.

[0133] Furthermore, it is necessary to calculate the capacity impact value according to the aforementioned first capacity and second capacity and the rated capacity of the battery cell; accordingly, as an example, according to the first capacity of the first battery cell, the second capacity of the first battery cell and the rated capacity of the battery cell, the capacity impact value of the first battery cell is obtained, including:

[0134] Calculating the sum of the charging capacity of the first battery cell and the discharging capacity of the first battery cell to obtain a first result;

[0135] The ratio of the first result to the rated capacity of the battery cell is calculated to obtain a capacity impact value of the first battery cell.

[0136] Specifically, according to the charging capacity of the first battery cell and the discharging capacity of the first battery cell obtained above, the sum of the charging capacity of the first battery cell and the discharging capacity of the first battery cell is calculated to obtain a first result; then, the ratio of the first result to the rated capacity of the battery cell is calculated to obtain the capacity impact value of the first battery cell. In practical applications, the rated capacity of a battery cell is an important parameter that describes the capacity of a battery cell to store electricity, indicating the minimum amount of electricity that a specified battery cell should be able to discharge under certain discharge conditions (such as discharge current and temperature, etc.). The capacity impact value obtained according to the ratio of the sum of the charging capacity of the first battery cell and the discharging capacity of the first battery cell to the rated capacity of the battery cell characterizes the degree of influence of the high charging and low discharging states on the capacity of the energy storage system; the accuracy of the calculation of the capacity impact value is improved.

[0137] Specifically, when it is necessary to accurately calculate the charging capacity and discharging capacity of the first battery cell, it is necessary to obtain an accurate standard charging voltage and a standard discharging voltage; accordingly, as an example, the processing module 22 is also used for:

[0138] Calculate the median or quantile of the voltage of all cells in the energy storage system at the end of charging to obtain the standard charging voltage;

[0139] Calculate the median or quantile of the voltage of all cells in the energy storage system at the end of discharge to obtain the standard discharge voltage.

[0140] Specifically, the aforementioned preset standard charging voltage and standard discharging voltage are obtained based on the charging voltage and discharging voltage of all cells in the energy storage system; in one example, the standard charging voltage can be determined by calculating the median of all charging voltages by calculating the charging voltage of all cells in the energy storage system at the end of charging; or the standard charging voltage can be determined according to the 95% quantile of the charging voltage of all cells at the end of charging. In another example, the standard discharge voltage can be determined by calculating the median of all discharge voltages by calculating the discharge voltage of all cells in the energy storage system at the end of discharge; or the standard discharge voltage can be determined according to the 95% quantile of the discharge voltage of all cells at the end of discharge; it should be noted that this example does not limit the specific method for determining the standard charging voltage and the standard discharge voltage. In this example, the standard charging voltage and the standard discharge voltage are determined according to the median or quantile of the charging voltage of all cells and the median or quantile of the discharge voltage; the accuracy of determining the standard charging voltage and the standard discharge voltage is improved.

[0141] Further, after the abnormal cells are identified, balancing is performed on some of the cells that are overcharged or undercharged; accordingly, as an example, the device further includes a balancing module 24, which is used to:

[0142] The equalization process is performed on a fourth cell other than the first cell among the second cell and the third cell.

[0143] For the aforementioned second and third cells that do not belong to the same cell, that is, the cells other than the first cell, balancing is performed. In practical applications, balancing the cells means using specific technologies and means to ensure that each single cell in the battery pack is as consistent as possible in terms of voltage, capacity and operating status; balancing can avoid the performance degradation of the entire battery pack due to the degradation of the performance of individual cells; at the same time, balancing can reduce the voltage and capacity differences between cells, reduce the internal resistance of the battery, and thus extend the service life of the cells; balancing can also prevent overcharging or over-discharging of cells, and reduce the risk of safety hazards such as thermal runaway. In this example, by performing balancing on cells that are overcharged or undercharged, the charge and discharge capacity of the entire energy storage system is improved, and the performance of the energy storage system is optimized.

[0144] Furthermore, the balancing module 24 is used for:

[0145] Calculating a capacity balancing value of the fourth battery cell according to the first charging voltage or the first discharging voltage of the fourth battery cell;

[0146] The fourth battery cell is subjected to equalization processing according to the capacity equalization value of the fourth battery cell.

[0147] Specifically, to perform balancing processing on the fourth battery cell, it is necessary to calculate the capacity balancing value of the fourth battery cell according to the first charging voltage or the first discharging voltage of the fourth battery cell; and to perform balancing processing on the fourth battery cell according to the fourth capacity balancing value. In this example, the fourth battery cell is balancing processed according to the capacity balancing value of the fourth battery cell, thereby improving the effect of balancing processing.

[0148] Furthermore, when performing the equalization process, it is necessary to accurately calculate the capacity equalization value corresponding to each battery cell; accordingly, as an example, according to the first charging voltage or the first discharging voltage of the fourth battery cell, the capacity equalization value of the fourth battery cell is calculated, including:

[0149] For the fourth battery cell that is only charged high, the sum of the products of the first time differences between charging at the standard charging voltage and the first charging voltage of the battery cell and the current at each time is calculated to obtain the charging capacity of the battery cell; the ratio of the charging capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell;

[0150] For the fourth battery cell where only discharge occurs, calculate the sum of the products of the second time differences between the discharge from the standard discharge voltage to the first discharge voltage of the battery cell and the current at each moment to obtain the discharge capacity of the battery cell; calculate the ratio of the discharge capacity of the battery cell to the rated capacity of the battery cell to obtain the capacity balance value of the battery cell.

[0151] Specifically, for the fourth battery cell that only experiences high charging, the sum of the products of the first time differences between charging with the standard charging voltage and the first charging voltage of the battery cell and the current at each moment is calculated to obtain the charging capacity of the battery cell; the ratio of the charging capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell; correspondingly, for the fourth battery cell that only experiences low charging, the sum of the products of the second time differences between discharging with the standard discharge voltage and the first discharge voltage of the battery cell and the current at each moment is calculated to obtain the discharge capacity of the battery cell; the ratio of the discharge capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell. Exemplarily, the calculation of the charging capacity of a battery cell that has only been charged up is consistent with the calculation method for calculating the charging capacity of the first battery cell described above; based on the known voltage value of the first charging voltage of the battery cell that has been charged up and the corresponding current value and time value, the product of the time difference between different times and the corresponding current value is calculated, and then all the time differences between charging the standard charging voltage to the first charging voltage of the battery cell and the product of the current are accumulated to obtain the charging capacity of the battery cell; the ratio of the charging capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell; similarly, the calculation of the discharge capacity of a battery cell that has only been discharged is consistent with the calculation method for calculating the discharge capacity of the first battery cell described above; based on the known voltage value of the first discharge voltage of the battery cell that has been discharged and the corresponding current value and time value, the product of the time difference between different times and the corresponding current value is calculated, and then all the time differences between discharging the standard discharge voltage to the first discharge voltage of the battery cell and the product of the current are accumulated to obtain the discharge capacity of the battery cell; the ratio of the discharge capacity of the battery cell to the rated capacity of the battery cell is calculated to obtain the capacity balance value of the battery cell. In this example, by calculating the charging capacity or discharging capacity of the battery cell that is overcharged or undercharged, the capacity balancing value of the corresponding battery cell is calculated, thereby improving the accuracy of the calculation result of the capacity balancing value.

[0152] After the capacity balancing value is obtained, the capacity balancing process is performed on the fourth battery cell; accordingly, as an example, the balancing module 24 is used to:

[0153] For the battery cell that is only highly charged in the fourth battery cell, the battery cell is discharged according to the capacity balance value of the battery cell until the battery capacity of the battery cell is equal to the second result; the second result represents the difference between the battery capacity of the battery cell before discharge and the capacity balance value of the battery cell;

[0154] For the battery cell that has only been discharged in the fourth battery cell, the battery cell is recharged according to the capacity balance value of the battery cell until the battery capacity of the battery cell is equal to the third result; the third result represents the sum of the battery capacity of the battery cell before recharging and the capacity balance value of the battery cell.

[0155] Specifically, after obtaining the capacity balancing value of the fourth battery cell, for the battery cell that is overcharged, the battery cell is discharged according to the obtained capacity balancing value of the battery cell, and the capacity of the battery cell is equal to the second result; wherein the second result represents the difference between the battery cell capacity before discharge and the capacity balancing value of the battery cell, that is, the battery cell capacity before balancing (before discharge) minus the calculated capacity balancing value. Exemplarily, according to the capacity balancing value, the battery cell capacity before discharge is discharged to a battery cell capacity equal to the capacity balancing value of the battery cell, and after releasing the capacity equal to the capacity balancing value, the battery cell capacity after balancing can be obtained; for the battery cell that is undercharged, according to the obtained capacity balancing value of the battery cell, the battery cell is supplemented to a battery cell capacity equal to the third result; wherein the third result represents the sum of the battery cell capacity before supplementation and the capacity balancing value of the battery cell, that is, the battery cell capacity before balancing (before supplementation) plus the calculated capacity balancing value. Exemplarily, according to the capacity balancing value, the battery cell is supplemented with electricity, and the battery cell capacity equal to the capacity balancing value of the battery cell is supplemented. After the battery cell is supplemented with electricity, the balanced battery cell capacity can be obtained. This example does not limit the balancing method of the battery cell; in practical applications, when the battery cell is balanced, the main balancing methods used include active balancing and passive balancing; active balancing is a technology that achieves balancing between battery cells by energy transfer, and uses a specific circuit structure and control strategy to supplement the power in the high-energy battery cell to the low-energy battery cell to achieve the optimization of the overall performance of the battery pack. Passive balancing is a method of dissipating extra energy through an external resistor or discharge device, which aims to solve the problem of inconsistent charge state and voltage between single cells in a battery pack; active balancing is balanced through a circuit structure composed of a circuit and a control chip, and uses an energy transfer device to transfer energy from a high-energy single cell to a low-energy single cell. Passive balancing dissipates extra energy through an external resistor or discharge device to achieve the purpose of balancing. In this example, by balancing the battery cell according to the capacity balancing value of the battery cell, the balancing effect of the battery cell is improved.

[0156] Further, when the determined capacity impact value of the first battery cell exceeds the threshold, it is considered that there is no abnormal battery cell in the energy storage system; accordingly, as an example, the identification module 23 is also used for:

[0157] If the capacity impact value of the first battery cell does not exceed the first preset threshold, it is determined that the first battery cell is not an abnormal battery cell.

[0158] Specifically, after the first battery cell is determined, its capacity impact value is calculated, and the obtained capacity impact value of the first battery cell is compared with the first preset value; if the capacity impact value of the battery cell does not exceed the first preset value, the first battery cell is determined not to be an abnormal battery cell. In this example, when a battery cell in the energy storage system is overcharged and undercharged, it is necessary to determine whether it is an abnormal battery cell based on the actual impact value of the battery cell being overcharged and undercharged; to avoid the situation where a battery cell is still determined to be an abnormal battery cell even though it is overcharged and undercharged but its impact on the energy storage system does not exceed the preset threshold. This improves the accuracy of identifying abnormal batteries in the energy storage system.

[0159] The abnormal battery cell identification device of the energy storage system provided in the present embodiment obtains the first battery cell in the energy storage system that has the phenomenon of high charging and low discharge; obtains the capacity influence value of the first battery cell according to the determined charging voltage and discharging voltage of the battery cell that has the phenomenon of high charging and low discharge; when the capacity influence value exceeds a preset threshold, the first battery cell is determined to be an abnormal battery cell; the scheme of the present application determines whether it is an abnormal battery cell according to the obtained capacity influence value, thereby improving the accuracy of abnormal battery cell identification; and the capacity influence value quantifies the degree of influence of the abnormal battery cell on the energy storage system, which can realize accurate judgment of the degree of influence of the abnormal battery cell on the energy storage system, and accurately and effectively perform corresponding optimization processing.

[0160] Embodiment 3

[0161] Figure 7 exemplarily shows a structural schematic diagram of an electronic device, the device comprising:

[0162] The device includes a processor 291 and a memory 292; it may also include a communication interface 293 and a bus 294. The processor 291, the memory 292, and the communication interface 293 may communicate with each other through the bus 294. The communication interface 293 may be used for information transmission. The processor 291 may call the logic instructions in the memory 292 to execute the above-mentioned example method.

[0163] In addition, the logic instructions in the above-mentioned memory 292 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product.

[0164] The memory 292 is a computer-readable storage medium that can be used to store software programs and computer executable programs, such as program instructions / modules corresponding to the methods in the embodiments of the present application. The processor 291 executes functional applications and data processing by running the software programs, instructions, and modules stored in the memory 292, that is, implementing the methods in the above method examples.

[0165] The memory 292 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required for at least one function; the data storage area may store data created according to the use of the terminal device, etc. In addition, the memory 292 may include a high-speed random access memory and may also include a non-volatile memory.

[0166] In the above embodiments, it should be understood that the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), etc. A general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the invention can be directly implemented as a hardware processor, or can be implemented by a combination of hardware and software modules in the processor.

[0167] The memory may include a high-speed memory (Random Access Memory, RAM), and may also include a non-volatile memory (NVM), such as at least one disk storage.

[0168] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the bus in the drawings of this application is not limited to only one bus or one type of bus.

[0169] The present application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0170] The present application also provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above method is implemented.

[0171] The above-mentioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special-purpose computer.

[0172] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (Application Specific Integrated Circuits, referred to as: ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0173] The division of units is only a logical function division, and there may be other divisions in actual implementation, such as 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 an indirect coupling or communication connection through some interface, device or unit, which can be electrical, mechanical or other forms.

[0174] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0175] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0176] If the function 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 invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. 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 methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0177] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, disk or optical disk and other media that can store program codes.

[0178] Finally, it should be noted that those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary technical means in the art not disclosed by the present invention, are not limited to the precise structure described above and shown in the drawings, and may be modified and changed in various ways without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for identifying abnormal cells in an energy storage system, characterized in that: include: Determine the first battery cell in the energy storage system that has a high-charge and low-discharge phenomenon; Obtaining a capacity impact value of the first battery cell according to a charging voltage and a discharging voltage of the first battery cell; The capacity impact value represents the degree of impact on the capacity of the energy storage system when the battery cell is overcharged and undercharged; If the capacity impact value of the first battery cell exceeds a first preset threshold, the first battery cell is determined to be an abnormal battery cell.

2. The method according to claim 1, characterized in that The method of determining the first battery cell in the energy storage system that has a high-charge and low-discharge phenomenon includes: Obtaining the first charging voltage of each battery cell at the end of charging and the first discharging voltage of each battery cell at the end of discharging in the energy storage system; the charging end time is the time when the voltage is last collected before the battery cell is charged; the discharging end time is the time when the voltage is last collected before the battery cell is discharged; According to the first charging voltage of each battery cell, a predetermined number of second battery cells are selected from each battery cell from large to small; according to the first discharging voltage of each battery cell, the same number of third battery cells are selected from each battery cell from small to large; The same battery cell between the second battery cell and the third battery cell is determined as the first battery cell.

3. The method according to claim 2, characterized in that The method of selecting a predetermined number of second battery cells from the battery cells in descending order according to the first charging voltage of each battery cell comprises: Sorting the first charging voltages of the battery cells from large to small to obtain a first sequence; A predetermined number of battery cells in front of the first sequence are selected as second battery cells.

4. The method according to claim 2, characterized in that: The selecting the same number of third battery cells from the battery cells in ascending order according to the first discharge voltage of each battery cell comprises: Sorting the first discharge voltages of the battery cells from small to large to obtain a second sequence; A predetermined number of battery cells in front of the second sequence are selected as third battery cells.

5. The method according to claim 2, characterized in that: After obtaining the first charging voltage of each battery cell in the energy storage system at the end of charging and the first discharging voltage of each battery cell at the end of discharging, the method further includes: Determine a maximum voltage among the first charging voltages of the battery cells and a minimum voltage among the first discharging voltages of the battery cells; The method of selecting a predetermined number of second battery cells from the battery cells in descending order according to the first charging voltage of each battery cell comprises: If the maximum voltage is greater than the second preset threshold and the minimum voltage is less than the third preset threshold, a predetermined number of second battery cells are selected from the battery cells in descending order according to the first charging voltages of the battery cells.

6. The method according to claim 5, characterized in that The method further comprises: If the maximum voltage is not greater than the second preset threshold or the minimum voltage is not less than the third preset threshold, abnormality identification is stopped.

7. The method according to claim 2, characterized in that The obtaining the capacity impact value of the first battery cell according to the charging voltage and the discharging voltage of the first battery cell comprises: The sum of the products of the first time differences between charging at the standard charging voltage and the first charging voltage of the first battery cell and the current at each moment is calculated to obtain the charging capacity of the first battery cell; the standard charging voltage is obtained based on the charging voltage of all batteries in the energy storage system at the moment of the charging end; the first time difference represents the time difference between any two moments between the moment of the standard charging voltage and the moment of the first charging voltage; The sum of the products of each second time difference between the discharge from the standard discharge voltage to the first discharge voltage of the first battery cell and the current at each moment is calculated to obtain the discharge capacity of the first battery cell; the standard discharge voltage is obtained based on the discharge voltage of all batteries in the energy storage system at the end of the discharge; the second time difference represents the time difference between any two moments between the moment of the standard discharge voltage and the moment of the first discharge voltage; A capacity impact value of the first battery cell is obtained according to the charging capacity of the first battery cell, the discharging capacity of the first battery cell and the rated capacity of the battery cell.

8. The method according to claim 7, characterized in that The obtaining the capacity impact value of the first battery cell according to the first capacity of the first battery cell, the second capacity of the first battery cell and the rated capacity of the battery cell includes: Calculating the sum of the charging capacity of the first battery cell and the discharging capacity of the first battery cell to obtain a first result; The ratio of the first result to the rated capacity of the battery cell is calculated to obtain a capacity impact value of the first battery cell.

9. The method according to claim 7, characterized in that: The method further comprises: Calculating the median or quantile of the voltages of all cells in the energy storage system at the end of charging to obtain the standard charging voltage; The median or quantile of the voltage of all the cells in the energy storage system at the end of the discharge is calculated to obtain the standard discharge voltage.

10. The method according to claim 8, characterized in that The method further comprises: An equalization process is performed on a fourth cell of the second cell and the third cell except the first cell.

11. The method according to claim 10, characterized in that The performing equalization processing comprises: Calculating a capacity balancing value of the fourth battery cell according to the first charging voltage or the first discharging voltage of the fourth battery cell; The fourth battery cell is subjected to a balancing process according to the capacity balancing value of the fourth battery cell.

12. The method according to claim 11, characterized in that The calculating the capacity balancing value of the fourth battery cell according to the first charging voltage or the first discharging voltage of the fourth battery cell comprises: For the fourth battery cell that is only charged high, calculate the sum of the products of the first time differences between charging from the standard charging voltage to the first charging voltage of the battery cell and the current at each time to obtain the charging capacity of the battery cell; calculate the ratio of the charging capacity of the battery cell to the rated capacity of the battery cell to obtain the capacity balance value of the battery cell; For the fourth battery cell in which only discharge occurs, calculate the sum of the products of the second time differences between discharging from the standard discharge voltage to the first discharge voltage of the battery cell and the current at each moment to obtain the discharge capacity of the battery cell; calculate the ratio of the discharge capacity of the battery cell to the rated capacity of the battery cell to obtain the capacity balance value of the battery cell.

13. The method according to claim 11, characterized in that The step of performing equalization processing on the fourth battery cell according to the capacity equalization value of the fourth battery cell comprises: For the battery cell that is only highly charged in the fourth battery cell, the battery cell is discharged according to the capacity balance value of the battery cell until the battery capacity of the battery cell is equal to the second result; the second result represents the difference between the battery capacity of the battery cell before discharge and the capacity balance value of the battery cell; For the battery cell that has only been discharged in the fourth battery cell, the battery cell is recharged according to the capacity balance value of the battery cell until the battery capacity of the battery cell is equal to the third result; the third result represents the sum of the battery capacity of the battery cell before recharging and the capacity balance value of the battery cell.

14. The method according to any one of claims 1 to 13, characterized in that: The method further comprises: If the capacity impact value of the first battery cell does not exceed the first preset threshold, it is determined that the first battery cell is not an abnormal battery cell.

15. An abnormal battery cell identification device for an energy storage system, characterized in that: include: A determination module, used to determine the first battery cell in the energy storage system that has a high-charge and low-discharge phenomenon; A processing module, configured to obtain a capacity impact value of the first battery cell according to a charging voltage and a discharging voltage of the first battery cell; the capacity impact value represents the degree of impact of the battery cell on the capacity of the energy storage system when a high-charge and low-discharge phenomenon occurs; The identification module is used to determine that if the capacity impact value of the first battery cell exceeds a first preset threshold value, then the first battery cell is determined to be an abnormal battery cell.

16. An electronic device, characterized in that: include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the method according to any one of claims 1 to 14.

17. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 14 when executed by a processor.

18. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 14 when being executed by a processor.

Images