Evaluation method for battery cell state of energy storage system and energy storage system

Abstract

The invention discloses an energy storage system cell state evaluation method and an energy storage system. The method comprises the steps of obtaining a real-time voltage value and a real-time temperature of each cell; determining a first undetermined state of each battery cell according to the real-time voltage value of each battery cell; obtaining a real-time calibration voltage value of each battery cell according to the real-time voltage value and the real-time temperature of each battery cell; determining a second undetermined state of each battery cell according to the real-time calibration voltage value of each battery cell; and when the first to-be-determined state and the second to-be-determined state of the target battery cell in the plurality of battery cells are abnormal, considering that the target battery cell is abnormal. The invention aims to solve the technical problem of monitoring the state of the battery cell in real time in the working process of the energy storage system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage safety, in particular to an evaluation method of a state of an energy storage system and the energy storage system. BACKGROUND

[0002] The distributed energy storage system (DESS) is widely used in various aspects of the power system as an important technical support for new energy generation and new power systems. The DC side of the energy storage system is generally composed of multiple cells in series and parallel, and can also output power according to user requirements. During the operation of the energy storage system, if a single cell is abnormal, the energy storage system may not work normally. Therefore, during the operation of the energy storage system, how to monitor the health state of the cell becomes a technical problem to be solved.

[0003] The above content is only used to assist in understanding the technical solutions of the present application and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0004] The main purpose of the present application is to provide an evaluation method of a state of an energy storage system and the energy storage system, which aims to solve the technical problem of real-time monitoring of the operating state of the cell during the operation of the energy storage system.

[0005] To achieve the above purpose, in a first aspect, the present application provides an evaluation method of a state of an energy storage system, the energy storage system comprising multiple cells arranged in series and parallel. The method can comprise: obtaining real-time voltage values and real-time temperatures of the cells; determining first pending states of the cells according to the real-time voltage values of the cells; obtaining real-time calibrated voltage values of the cells according to the real-time voltage values and the real-time temperatures of the cells; determining second pending states of the cells according to the real-time calibrated voltage values of the cells; and determining that a target cell in the multiple cells is abnormal when the first pending state and the second pending state of the target cell are both in an abnormal state.

[0006] Optionally, the determination of the first pending state of the cell according to the real-time voltage value of the cell can specifically comprise: determining a first data interval according to the real-time voltage values of the multiple cells; determining that the first pending state of the target cell is normal when the real-time voltage value of the target cell is a value in the first data interval; and determining that the first pending state of the target cell is abnormal when the real-time voltage value of the target cell is not a value in the first data interval.

[0007] Optionally, the determination of the first data interval according to the real-time voltage values of the multiple cells can specifically comprise: determining the first data interval according to the real-time voltage average and the real-time voltage standard deviation of the multiple cells.

[0008] Optionally, the first data interval can be: (μ1-3 , μ1+3 ).

[0009] wherein μ1 represents the real-time voltage average value of the plurality of battery cells, represents the real-time voltage standard deviation of the plurality of battery cells.

[0010] Optionally, the real-time calibration voltage value of each battery cell according to the real-time voltage value and the real-time temperature of each battery cell comprises: determining the corresponding relationship between the battery cell temperature and the standard voltage value according to the real-time voltage average value and the real-time temperature average value of the plurality of battery cells; determining the standard voltage value corresponding to each battery cell at the real-time temperature based on the corresponding relationship; and determining the real-time calibration voltage value of each battery cell based on the standard voltage value and the real-time voltage value of each battery cell.

[0011] Optionally, the real-time calibration voltage value of each battery cell based on the standard voltage value and the real-time voltage value of each battery cell can specifically comprise: when the energy storage system is in a charging state, calculating the difference between the real-time voltage value of each battery cell multiplied by 2 and the corresponding standard voltage value to obtain the real-time calibration voltage value of each battery cell. Or, when the energy storage system is in a discharging state, the standard voltage value corresponding to each battery cell is taken as the real-time calibration voltage value of each battery cell.

[0012] Optionally, the second pending state of each battery cell according to the real-time calibration voltage value of each battery cell can specifically comprise: determining the second data interval according to the real-time calibration voltage value of the plurality of battery cells; when the real-time calibration voltage value of the target battery cell is a value in the second data interval, determining that the second pending state of the target battery cell is a normal state; and when the real-time calibration voltage value of the target battery cell is not a value in the second data interval, determining that the second pending state of the target battery cell is an abnormal state.

[0013] Optionally, the second data interval determined according to the real-time calibration voltage value of the plurality of battery cells comprises: determining the second data interval according to the real-time calibration voltage average value and the real-time calibration voltage standard deviation of the plurality of battery cells.

[0014] Optionally, the second data interval can be: (μ2-3 , μ2+3 ).

[0015] wherein μ2 represents the real-time calibration voltage average value of the plurality of battery cells, represents the real-time calibration voltage standard deviation of the plurality of battery cells.

[0016] In a second aspect, the present application also provides a kind of energy storage system, the energy storage system includes multiple electric cores and processing device, multiple electric cores and processing device are coupled.Processing device includes memory and one or more processors, memory and processor are coupled.Wherein, memory is used to store computer program code, computer program code includes computer instructions, when processor executes computer instructions, make processing device execute the method in the first aspect and any optional mode thereof.

[0017] In the implementation of the present application, the state of the battery cell is determined by monitoring the real-time voltage and real-time temperature of the battery cell. On the one hand, the state of the battery cell is determined based on the real-time voltage average and the real-time voltage standard deviation. On the other hand, the real-time voltage value is first calibrated according to the real-time temperature, and the state of the battery cell is determined based on the calibrated voltage average and the calibrated voltage standard deviation. If the data of the two aspects reflects that the battery cell is abnormal, the battery cell is determined to be an abnormal battery cell. Through the evaluation of the two aspects, the state of the battery cell is finally determined, which improves the accuracy of the battery cell health state determination, and the real-time determination method based on real-time data helps to find abnormal battery cells early and maintain the safe and stable operation of the energy storage system. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A flowchart of the evaluation method of the state of the battery cell of the energy storage system provided by the embodiment of the present application is provided. Figure 2 A flowchart of determining the real-time standard voltage of the battery cell provided by the embodiment of the present application is provided. Figure 3 Another flowchart of the evaluation method of the state of the battery cell of the energy storage system provided by the embodiment of the present application is provided. Figure 4 A schematic diagram of the temperature-voltage fitting curve provided by the embodiment of the present application is provided. Figure 5 A schematic diagram of the structure of the energy storage system provided by the embodiment of the present application is provided. Figure 6 A schematic diagram of the entity structure of the evaluation device of the state of the battery cell of the energy storage system provided by the embodiment of the present application is provided. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] If the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. For example, "A and / or B" includes A scheme, or B scheme, or A and B scheme. In addition, the technical solutions of each embodiment can be combined with each other, but must be based on the realization of ordinary skilled in the art. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0021] In addition, the technical solutions of each embodiment can be combined with each other, but must be based on the realization of ordinary skilled in the art. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0022] The distributed energy storage system is a kind of energy storage device arranged in power user side or distribution network node, and the energy storage system is generally small and medium-sized. Among them, the DC side of the energy storage system is generally connected in series and parallel mode by multiple battery cells to provide the required power and energy. During the working process of the energy storage system, if there is an abnormal performance of a single battery cell, it may cause the energy storage system to fail to operate normally, affecting power transmission and power use. In order to maintain the normal and stable operation of the energy storage system, it is necessary to judge the working state of the battery cell in the energy storage system in advance, so as to maintain the normal operation of the energy storage system.

[0023] For example, in a battery pack composed of multiple battery cells in series and parallel, the working state of the battery pack can be judged by temperature correction. For example, the ambient temperature of the battery pack, the charge and discharge time of the battery pack, the first temperature of the battery cell and the heat dissipation power of the battery cell are obtained. The first temperature of the battery cell is corrected based on the ambient temperature, the charge and discharge time of the battery pack and the heat dissipation power of the battery cell, and the second temperature of the battery cell is obtained. That is, the corrected battery cell temperature.

[0024] It can be understood that in this temperature correction method, the real-time and accuracy of temperature protection measures can be effectively improved in the scene of ambient temperature change. However, this method only detects the temperature of the battery cell, and the obtained parameters are less, which may result in inaccurate judgment. In addition, this embodiment does not consider the scenario that the battery cells at different positions have different heat dissipation effects due to the positions, which leads to different battery cell temperatures and inconsistent battery cell voltages.

[0025] In the process of operation of the energy storage system, if various data can be monitored in real time, and the health state of the battery cell is judged according to the monitoring data, or the voltage or temperature data is corrected according to the monitoring data, and then the state of the battery cell in the energy storage system is accurately judged.

[0026] Based on this, the embodiment of the present application provides an evaluation method for the state of the battery cell of the energy storage system. When the energy storage system operates the method, the real-time temperature and the real-time voltage value of the battery cell can be monitored in real time. On the one hand, the state of the battery cell can be judged according to the voltage value of the battery cell; on the other hand, the voltage value of the battery cell can be calibrated according to the real-time temperature, and the state of the battery cell is judged based on the calibrated voltage value of the battery cell. When the judgment results of the two aspects both indicate that the battery cell is in an abnormal state, the battery cell is determined to be an abnormal battery cell, and the number of the battery cell is prompted to the operator, so as to maintain the normal operation of the energy storage system.

[0027] For example, when the health state of the battery cell is judged according to the real-time voltage value, the real-time voltage average value and the real-time voltage standard deviation of all battery cells can be determined according to the real-time voltage value, the data interval of the battery health state is determined based on the voltage average value and the real-time voltage standard deviation, and if the real-time voltage value is a value in the data interval of the battery health state, it can be determined that the battery cell corresponding to the real-time voltage value is in a healthy operating state.

[0028] In addition, the calibration of the real-time voltage according to the real-time temperature can also be implemented at the same time, so as to determine the calibration voltage value of each battery cell, and then determine the calibration voltage average value and the calibration voltage standard deviation. The data interval of the battery health state is determined according to the calibration voltage average value and the calibration voltage standard deviation, and if the calibration voltage value is in the data interval of the battery health state, it can be determined that the battery cell corresponding to the calibration voltage value is in a healthy operating state.

[0029] The two judgment methods can be implemented at the same time, and when the battery cell is determined to be in an abnormal state by both methods, a prompt information can be sent to prompt that the state of the battery cell is abnormal.

[0030] Please refer to Figure 1 The evaluation method for the state of the battery cell of the energy storage system provided by the embodiment of the present application is shown in the flow chart as Figure 1 The method can include steps 101-105.

[0031] Step 101: Obtain the real-time voltage value and the real-time temperature of each battery cell.

[0032] Among them, the energy storage system includes a plurality of battery cells arranged in series and in parallel. When the energy storage system starts to operate, that is, starts to be in a discharging state or a charging state, the real-time voltage value and the real-time temperature of each battery cell in the energy storage system are obtained in real time.

[0033] Step 102: determining the first pending state of each battery cell according to the real-time voltage value of each battery cell.

[0034] In a specific implementation, the real-time voltage value of the battery cell can be judged by setting a preset threshold or a preset data interval to determine the first pending state of the battery cell. For example, if the real-time voltage value of the battery cell is greater than the preset threshold, the first pending state of the battery cell is determined to be an abnormal state. For another example, if the real-time voltage value of the battery cell is not a value in the preset data interval, the first pending state of the battery cell is determined to be an abnormal state. Therefore, the application does not limit the determination method of the first pending state of the battery cell.

[0035] In one possible implementation, a first data interval is determined based on the obtained real-time voltage values of all battery cells. If the real-time voltage value of the battery cell is a value in the first data interval, the first pending state of the battery cell is determined to be normal. If the real-time voltage value of the battery cell is not a value in the first data interval, the first pending state of the battery cell is determined to be an abnormal state.

[0036] Wherein, the real-time voltage value of each battery cell needs to be judged to determine the first pending state of each battery cell.

[0037] For example, the first data interval can be determined according to the real-time voltage average value and the real-time voltage standard deviation. For example, the first data interval can be (μ1-3 , μ1+3 ).

[0038] Wherein, μ1 represents the real-time voltage average value of all battery cells, represents the real-time voltage standard deviation of all battery cells.

[0039] The real-time voltage average value and the real-time voltage standard deviation can be determined by using a known calculation method. For example, in an energy storage system including N battery cells, N real-time voltages and real-time temperatures can be obtained. For example, the real-time voltage average value can be calculated by using the following formula 1: μ1 = (V1_cell1 + V1_cell2 + … + V1_celln) / N Formula 1 Wherein, μ1 represents the calculated real-time voltage average value, V1_cell1 represents the real-time voltage value of the first battery cell, …, V1_celln represents the real-time voltage value of the nth battery cell, and N represents the number of battery cells in the energy storage system.

[0040] The real-time voltage standard deviation can be calculated by using the following formula 2: Formula 2 Wherein, represents the calculated real-time voltage standard deviation, μ1 represents the real-time voltage average value, V1_cell1 represents the real-time voltage value of the first battery cell, …, V1_celln represents the real-time voltage value of the nth battery cell, and N represents the number of battery cells in the energy storage system.

[0041] Specifically, after determining the first pending state of each battery cell, a first lookup table can be generated according to the first pending state of each battery cell, and the first lookup table is used to record the battery cell number in the abnormal state. For example, the real-time voltage value of the first battery cell is V1_cell1, if V1_cell1 < μ1-3 or V1_cell1 > μ1+3 then it can be determined that the first pending state of the first battery cell is abnormal, and the battery cell number cell1 of the first battery cell is recorded in the first lookup table.

[0042] It should be noted that the above first data interval is set based on the fact that the voltage of the battery cells in the energy storage system conforms to the normal distribution under ideal conditions. In specific implementation, the first data interval can also be determined according to empirical values or other preset rules. Here, only an example is given, and the determination of the first data interval is not specifically limited.

[0043] Step 103: obtaining the real-time calibrated voltage value of each battery cell according to the real-time voltage value and the real-time temperature of each battery cell.

[0044] In some embodiments, the real-time voltage average value and the real-time temperature average value of all battery cells (i.e., multiple battery cells) can be determined according to the obtained real-time voltage value and the real-time temperature of each battery cell, and then the corresponding relationship between the battery cell temperature and the standard voltage can be determined based on the real-time voltage average value and the real-time temperature average value of the multiple battery cells. Further, the standard voltage value of the battery cell at the real-time temperature can be determined according to the corresponding relationship between the battery cell temperature and the standard voltage, and then the real-time voltage value can be calibrated according to the standard voltage value to obtain the real-time calibrated voltage value.

[0045] For example, the corresponding relationship between the battery cell temperature and the standard voltage can be determined based on the preset data relationship according to the real-time voltage average value and the real-time temperature average value of all battery cells at each time point from the charging or discharging time point to the current data acquisition time point of the energy storage system.

[0046] For example, the energy storage system obtains the real-time voltage value and the real-time temperature at a data collection time (e.g., at time T0), and determines the temperature-standard voltage correspondence of the battery cell based on a preset data processing mode. At the next data collection time, i.e., at time T1 which is the next time of time T0, the real-time voltage value and the real-time temperature value of the battery cell are obtained. The data processing can be performed according to the temperature-standard voltage correspondence of the battery cell at time T0, and the real-time voltage value and the real-time temperature value at time T1, to generate the temperature-standard voltage correspondence of the battery cell at time T1.

[0047] It can be understood that during the operation of the energy storage system, the temperature-standard voltage correspondence of the battery cell can be generated according to the collected data at each data collection time. That is, the temperature-standard voltage correspondence of the battery cell needs to be updated according to the collected data at each data collection time, so that the temperature-standard voltage correspondence of the battery cell reflects the real-time correlation between the current battery cell and the standard voltage.

[0048] For example, the temperature-standard voltage correspondence of the battery cell is determined according to the real-time voltage value and the real-time temperature obtained at all data collection times. Please refer to Figure 2 for a method of determining the real-time standard voltage of the battery cell. As shown in Figure 2 , the method includes steps 21-23.

[0049] Step 21: determining the temperature-standard voltage correspondence of the battery cell according to the real-time voltage average value and the real-time temperature average value of the plurality of battery cells.

[0050] In each data collection time, the real-time voltage average value and the real-time temperature average value of the plurality of battery cells are first calculated based on the real-time voltage value and the real-time temperature of each battery cell. Then, the real-time voltage average value and the real-time temperature average value at each time are data fitted based on the preset data processing mode, to generate the temperature-standard voltage correspondence of the battery cell.

[0051] In a possible real-time mode, the preset temperature-standard voltage correspondence of the battery cell can be represented by the following formula 3: μ1 =a avgT1 2 +b avgT1 +c formula 3 Wherein, a, b and c are fitting coefficients, avgT1 represents the real-time temperature average value at time T1, and μ1 represents the real-time voltage average value at time T1. When the data relationship obtained by fitting the real-time temperature average value and the real-time voltage average value at multiple data collection times is the temperature-standard voltage correspondence of the battery cell. For example, a data processing tool (or data processing software, etc.) can be used for data fitting.

[0052] Step 22: Determine the standard voltage value corresponding to the real-time temperature of each battery cell based on the correspondence relationship.

[0053] In one possible implementation, a battery cell temperature-standard voltage table can be generated based on the battery cell temperature-standard voltage correspondence relationship. The standard voltage value corresponding to the real-time temperature of the battery cell can also be determined by looking up the table.

[0054] Step 23: Determine the real-time calibration voltage value of each battery cell based on the standard voltage value and the real-time voltage value of each battery cell.

[0055] In one possible implementation, different voltage calibration methods can be used when the energy storage system is in the charging or discharging process. For example, the state of the energy storage system can be determined according to the total power output in the energy storage system. When the total power output is positive, it is determined that the energy storage system is currently in the discharging state. When the total power output is negative, it is determined that the energy storage system is currently in the charging state. In addition, the charging and discharging state of the energy storage system can also be determined according to the current value on the DC side of the energy storage system, or the charging and discharging state of the energy storage system can also be determined according to the power output of the power conversion system (PCS) in the energy storage system. The values used to determine the charging and discharging of the energy storage system are not limited in the present application, which are only examples here.

[0056] For example, when the energy storage system is in the charging process, the real-time voltage value of the battery cell can be calibrated using the following formula 4.

[0057] V2_celln = V1_celln - (μ1' - V1_celln) Formula 4 Where V2_celln represents the real-time calibration voltage value of the battery cell, V1_celln represents the real-time voltage value of the battery cell, and μ1' represents the standard voltage corresponding to the real-time temperature value of the battery cell.

[0058] When the energy storage system is in the discharging process, the real-time voltage of the battery cell can be calibrated using the following formula 5.

[0059] V2_celln = V1_celln + (μ1' - V1_celln) Formula 5 Where V2_celln represents the real-time calibration voltage value of the battery cell, V1_celln represents the real-time voltage value of the battery cell, and μ1' represents the standard voltage corresponding to the real-time temperature value of the battery cell.

[0060] It can be understood that in the process of calibrating the real-time voltage value of the battery cell, each battery cell in the energy storage system needs to be traversed, and the real-time voltage value of each battery cell needs to be calibrated to determine the real-time calibration voltage value of each battery cell.

[0061] It should be noted that after the real-time voltage value of the battery cell is calibrated, the standard voltage value is determined based on the real-time temperature value in the corresponding relationship between the battery cell temperature and the standard voltage, and the real-time voltage value is calibrated based on the standard voltage value. It can be understood that in the process of calibration, the real-time voltage value is calibrated based on the average voltage value at the same average temperature, and this calibration method helps to ignore the influence of different positions and temperatures of the battery cells in the energy storage system on the real-time voltage value of the battery cells. That is, based on the same average temperature, the real-time voltage value is calibrated by using the standard voltage value, which can be considered as the real-time voltage value determined at the same temperature, so as to eliminate the influence of the spatial distribution of the battery cells in the energy storage system on the state evaluation result of the battery cells. Further improve the accuracy of the state evaluation of the energy storage system in complex environment.

[0062] Step 104: determining the second pending state of each battery cell according to the real-time calibrated voltage value of each battery cell.

[0063] In a possible implementation, the second data interval can be determined according to the real-time calibrated voltage value of the plurality of battery cells. The real-time calibrated voltage value of each battery cell is judged in sequence. If the real-time calibrated voltage value of the battery cell is a value in the second data interval, it is determined that the second pending state of the battery cell is a normal state. If the real-time calibrated voltage value of the battery cell is not a value in the second data interval, it is determined that the second pending state of the battery cell is an abnormal state.

[0064] For example, the second data interval can be (μ2-3 , μ2+3 ). Wherein, μ2 is the real-time calibrated voltage average value, is the real-time calibrated voltage standard deviation.

[0065] It should be understood that the real-time calibrated voltage average value and the real-time calibrated voltage standard deviation can be obtained by using a known calculation method, which will not be described here.

[0066] When the real-time calibrated voltage value of the battery cell is a value in the second data interval, it can be determined that the second pending state of the battery cell is a normal state. If the real-time calibrated voltage value of the battery cell is not a value in the second data interval, it can be determined that the second pending state of the battery cell is an abnormal state.

[0067] Specifically, a second lookup table can also be set to record the battery cell number of the battery cell with the second pending state of the abnormal state.

[0068] It should be noted that the above-mentioned second data interval is only an example. In specific implementation, the second data interval can also be determined according to an empirical value or other preset rules. In the embodiment of the present application, the determination of the second data interval is not limited specifically.

[0069] Step 105: When the first pending state and the second pending state of the target battery cell in the plurality of battery cells are both in the abnormal state, determining that the target battery cell is abnormal.

[0070] In a possible implementation, if the first lookup table and the second lookup table are set, the first lookup table records the battery cell numbers whose first pending state is the abnormal state, and the second lookup table records the battery cell numbers whose second pending state is the abnormal state. The battery cell numbers whose first pending state and second pending state both indicate that the battery cell is abnormal can be determined by querying the first lookup table and the second lookup table, and the battery cell numbers are confirmed as the numbers of the battery cells in the abnormal state.

[0071] It should be noted that the method 102 and the steps 103-104 described above in the embodiments of the present application do not have a strict execution sequence. The step 102 can be executed to determine the first pending state of the battery cell, and the steps 103-104 can be executed to determine the second pending state of the battery cell. In a specific implementation, the steps 102-104 can be executed in sequence according to the method in Figure 1 , or the steps 103-104 can be executed first, and then the step 102 can be executed, or the step 102 and the steps 103-104 can be executed simultaneously. That is, there is no obvious sequence requirement when determining the first pending state and the second pending state of the battery cell. Therefore, the above method does not limit the sequence of the first pending state and the second pending state in the implementation.

[0072] In a possible implementation, the first lookup table and the second lookup table can be set, and the abnormal library can be determined based on the first lookup table and the second lookup table. The abnormal library is used to record the battery cell numbers included in the first lookup table and the second lookup table. When a user checks the abnormal library, the battery cell numbers in the abnormal state can be known. Alternatively, the energy storage device can generate prompt information according to the data in the abnormal library, and the prompt information can include the battery cell numbers in the abnormal state.

[0073] In a possible implementation, the two evaluation methods can be independently operated. Please refer to Figure 3 , which is a flow chart of an evaluation method of a battery cell state of an energy storage system provided in the embodiments of the present application. As shown in Figure 3 , the evaluation method includes S01-S08.

[0074] S01: Obtain real-time voltage values and real-time temperatures of a plurality of battery cells.

[0075] S02: Calculate the average value and the standard deviation of the real-time voltage values to determine a first data interval.

[0076] S03: Record the cell number of each cell whose real-time voltage value exceeds the first data interval in the first lookup table.

[0077] S04: Fit the correspondence between the cell temperature and the standard voltage.

[0078] S05: Determine the real-time calibration voltage value of the cell based on the correspondence between the cell temperature and the standard voltage.

[0079] S06: Calculate the average value and the standard deviation of the real-time calibration voltage value to determine the second data interval.

[0080] S07: Record the cell number of each cell whose real-time voltage value exceeds the second data interval in the second lookup table.

[0081] S08: List the cell number included in both the first lookup table and the second lookup table in the exception library.

[0082] In a specific real-time, at the time when the energy storage system runs for 25 minutes, the real-time voltage average value and the real-time voltage standard deviation at the current time are calculated, and based on the first data interval, it is determined that the real-time voltage values of 7 cells in the energy storage device indicate that the cells are in an abnormal state of health status. For example, the cell numbers of these 7 cells are: 8, 9, 119, 217, 218, and 233. Therefore, the cell numbers in the first lookup table are: 8, 9, 119, 217, 218, and 233.

[0083] Among them, within about 25 minutes, the real-time temperature and real-time voltage value of all cells at each time are collected, with a sampling period of 2S (seconds) each time, including 1500 sampling points. Please refer to Figure 4 , which is a temperature-voltage fitting curve obtained based on the preset data fitting method after the above sampling. As Figure 4 shown, based on the 1500 sampling points, the current collected data is fitted based on the above formula 3, and the curve relationship equation after fitting is: μ1’=0.0122 avgT12 – 0.6977avgT1 +13.35.

[0084] Based on the above temperature-voltage relationship, the real-time voltage of each cell can be calibrated to obtain the real-time calibration voltage value, and the real-time calibration voltage average value and the real-time calibration voltage standard deviation can be calculated according to the calibration voltage values of all cells.

[0085] The numerical calculation process will not be described in detail, and these values calculated are represented by Table 1 as follows.

[0086]

[0087] Table 1 Calculation of Calibration Voltage Value, Calibration Voltage Average Value, and Calibration Voltage Standard Deviation Data Table If the real-time calibration voltage value is determined according to the calculation, and it is determined whether the real-time calibration voltage value is data in the second data interval. The cell number corresponding to the real-time voltage calibration value not belonging to the second data interval is listed in the second lookup table. If it is found that the second lookup table is empty, that is, it does not include any cell number. Therefore, it can be determined that there is no repeated cell number in the first lookup table and the second lookup table, and therefore, at the current time, there is no cell in the abnormal state in the energy storage system.

[0088] The embodiment of the present application also provides a kind of energy storage system, please refer to Figure 5 It is the structural schematic diagram of a kind of energy storage system provided by the embodiment of the present application.As shown in Figure 5 The energy storage system includes cell unit 41, memory 42 and processor 43. The cell unit includes a plurality of cells connected in series and parallel in the energy storage system. The cell unit 41 and the processor 43 can be interconnected by wire, and the memory and the processor are coupled. The memory is used to store computer program code, and the computer program code includes computer instructions, which makes the processing device execute the real-time steps in the above method embodiments when the processor executes the computer instructions.

[0089] On the basis of the above embodiment, the embodiment of the present application further provides an evaluation device for the state of the energy storage system cell. Figure 6 It is the entity structure schematic diagram of an evaluation device for the state of the energy storage system cell provided by the embodiment of the present application, as Figure 6 As shown in the figure, the evaluation device 600 for the state of the energy storage system cell can include: processor (processor) 610, communication interface (Communications Interface) 620, memory (memory) 630 and communication bus 640, wherein the processor 610, the communication interface 620, the memory 630 are communicated with each other through the communication bus 640. The processor 610 can call the logic instructions in the memory 630 to execute the above evaluation method.

[0090] In addition, the logic instructions in the memory 630 described above can be implemented in the form of a software function unit and sold or used as an independent product, and can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0091] The embodiments of the present application also provide a computer storage medium, which includes computer instructions, when the computer instructions are executed on the processing device, the processing device can execute the method steps in the method embodiments described above.

[0092] The embodiments of the present application also provide a computer program product, when the computer program product is executed on the processing device, the processing device can execute the method steps in the method embodiments described above.

[0093] In the embodiments provided by the present application, it should be understood that the disclosed devices and methods can be implemented in other manners. For example, the device embodiments described above are merely schematic; the division of the modules or units is merely logical function division; there can be another division manner in actual implementation; for example, a plurality of units or components can be combined or integrated into another device, or some features can be ignored or not executed. In addition, the communication connection between the units described in the embodiments of the present application can be indirect connection or direct communication connection through some interfaces, devices or units, which can be electrical, mechanical or in other forms.

[0094] The units described as separate components can or can not be physically separate, and can be one physical unit or a plurality of physical units as three components, that is, can be located in one place, or can be distributed to a plurality of different places, and some or all of them can be selected to achieve the technical purposes of the embodiments of the present application according to actual needs.

[0095] In addition, the functional units in the embodiments of the present application can be integrated on one processing unit, or each unit can be physically present independently, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software function unit.

[0096] It can be understood that, in order to implement the above functions, the energy storage system cell health state prompting device comprises a hardware structure and / or a software module corresponding to each function. Those skilled in the art should easily realize that, in combination with the embodiments disclosed in the present application, the units and implementation steps of each example described in the present application can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is realized in the form of hardware or program driving depends on the specific application and design constraints of the technical solution. Those skilled in the art can adapt different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of the present application.

[0097] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method of evaluating the state of an energy storage system cell, characterized by, The energy storage system includes a plurality of battery cells, and the method comprises: obtaining real-time voltage values and real-time temperatures of the battery cells; determining first pending states of the battery cells according to the real-time voltage values of the battery cells; obtaining real-time calibration voltage values of the battery cells according to the real-time voltage values and the real-time temperatures of the battery cells; determining second pending states of the battery cells according to the real-time calibration voltage values of the battery cells; when the first pending state and the second pending state of a target battery cell in the plurality of battery cells are both in an abnormal state, determining that the target battery cell is abnormal.

2. The method of claim 1, wherein, The determination of the first pending state of the battery cell according to the real-time voltage value of the battery cell comprises: determining a first data interval according to the real-time voltage values of the plurality of battery cells; when the real-time voltage value of the target battery cell is a value in the first data interval, determining that the first pending state of the target battery cell is a normal state; when the real-time voltage value of the target battery cell is not a value in the first data interval, determining that the first pending state of the target battery cell is an abnormal state.

3. The method of claim 2, wherein, The determination of the first data interval according to the real-time voltage values of the plurality of battery cells comprises: determining the first data interval according to the real-time voltage average value and the real-time voltage standard deviation of the plurality of battery cells.

4. The method of claim 3, wherein The first data interval is: (μ1-3 , μ1+3 ); wherein μ1 represents a real-time voltage average value of the plurality of battery cells, represents a real-time voltage standard deviation of the plurality of battery cells.

5. The method of claim 1, wherein, The obtaining of the real-time calibration voltage value of the battery cell according to the real-time voltage value and the real-time temperature of the battery cell comprises: determining a corresponding relationship between battery cell temperatures and standard voltage values according to the real-time voltage average value and the real-time temperature average value of the plurality of battery cells; determining the standard voltage value corresponding to the real-time temperature of each battery cell based on the corresponding relationship; determining the real-time calibration voltage value of each battery cell based on the standard voltage value and the real-time voltage value of each battery cell.

6. The method of claim 5, wherein, The determination of the real-time calibration voltage value of the battery cell based on the standard voltage value and the real-time voltage value of the battery cell comprises: when the energy storage system is in a charging state, calculating the difference between the real-time voltage value of each battery cell multiplied by 2 and the corresponding standard voltage value to obtain the real-time calibration voltage value of each battery cell; or, when the energy storage system is in a discharging state, taking the standard voltage value corresponding to each battery cell as the real-time calibration voltage value of each battery cell.

7. The method according to any one of claims 1 to 6, characterized in that, The determination of the second pending state of the battery cell according to the real-time calibration voltage value of the battery cell comprises: determining a second data interval according to the real-time calibration voltage values of the plurality of battery cells; when the real-time calibration voltage value of the target battery cell is a value in the second data interval, determining that the second pending state of the target battery cell is a normal state; when the real-time calibration voltage value of the target battery cell is not a value in the second data interval, determining that the second pending state of the target battery cell is an abnormal state.

8. The method of claim 7, wherein, The determination of the second data interval according to the real-time calibration voltage values of the plurality of battery cells comprises: determining the second data interval according to the real-time calibration voltage average value and the real-time calibration voltage standard deviation of the plurality of battery cells.

9. The method of claim 8, wherein The second data interval is: (μ2-3 , μ2+3 ); wherein μ2 represents a real-time calibration voltage average value of the plurality of battery cells, represents a real-time calibration voltage standard deviation of the plurality of battery cells.

10. An energy storage system characterized by, comprises: a plurality of cells and a processing device; the plurality of cells and the processing device are coupled; the processing device comprises a memory and one or more processors, the memory and the processors are coupled; wherein the memory is configured to store computer program code comprising computer instructions that, when executed by the processors, cause the processing device to perform the method of any one of claims 1 to 9.

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