Method, system, device and medium for online updating of lithium battery open circuit voltage curve

Abstract

The application provides a lithium battery open-circuit voltage curve online updating method, system, device and medium. The method is to load the obtained open-circuit voltage-remaining capacity curve offline data to a battery management system as reference data, obtain the discharge capacity and open-circuit voltage after a preset time interval under the full charge state of the lithium battery to be evaluated, obtain the reference remaining capacity and reference open-circuit voltage of the current life state according to the discharge capacity and the reference data, when the open-circuit voltage meets the open-circuit voltage updating condition, obtain the open-circuit voltage-remaining capacity curve updating data according to the open-circuit voltage-discharge capacity curve data obtained by converting the reference data and the preset discharge weight table, and perform weighted summation on the open-circuit voltage-remaining capacity curve updating data and the corresponding open-circuit voltage-remaining capacity curve offline data to update the open-circuit voltage-remaining capacity curve reference data. The application can simply and efficiently continuously and accurately update the open-circuit voltage of the lithium battery under different life states.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a method, system, computer device, and storage medium for online updating of the open-circuit voltage curve of a lithium battery. Background Technology

[0002] Estimating the remaining charge (SOC) of a power battery is one of the core functions of a battery management system (BMS). Accurate SOC estimation is of great significance for ensuring the safe and reliable operation of power batteries, improving the efficient utilization of stored energy and power, optimizing energy management and safety management, preventing overcharging and over-discharging of power batteries, and ensuring their long-term operation.

[0003] In practical applications, SOC estimation often relies heavily on the Open Circuit Voltage (OCV) curve. Furthermore, as an electrochemical product, the parameters of a battery, including OCV, change with use and storage; that is, different parameters correspond to different lifespan states. Existing methods that provide initial OCV parameters when the battery is put into use, or provide OCV parameters at different lifespans as input to the BMS for SOC estimation, suffer from inconsistencies in the aging paths of batteries under different usage conditions. This leads to discrepancies between the pre-measured offline data and actual values, posing a significant challenge to high-accuracy SOC estimation throughout the battery's entire lifespan. Although some researchers have proposed updating OCV values ​​at different lifespan states through online parameter identification of the lithium battery equivalent circuit model parameters, this approach is only theoretically feasible. Accurate parameter identification is difficult to achieve in practical applications, failing to meet real-world requirements. Therefore, there is an urgent need for a method that can accurately and efficiently update the OCV curve online to improve the reliability of SOC estimation throughout the entire lifespan. Summary of the Invention

[0004] The purpose of this invention is to provide an online update method for the open-circuit voltage (OCV) curve of a lithium battery. This method involves weighted averaging of the OCV-remaining capacity curve data obtained from offline measurements under different lifespan conditions with the updated OCV-remaining capacity curve data obtained from online updates during static loading. This continuous iterative update of the OCV curve under different lifespan conditions addresses the shortcomings of existing online OCV curve update schemes. It provides a simple and efficient way to continuously and accurately update the OCV curve under different lifespan conditions of lithium batteries, ensuring the accuracy of SOC estimation throughout the entire lifespan and improving application value.

[0005] To achieve the above objectives, it is necessary to provide a method, system, computer equipment, and storage medium for online updating of the open-circuit voltage curve of a lithium battery, addressing the aforementioned technical problems.

[0006] In a first aspect, embodiments of the present invention provide a method for online updating of the open-circuit voltage curve of a lithium battery, the method comprising the following steps: Offline testing was conducted to obtain offline data of the open-circuit voltage-remaining capacity curve of the lithium battery under different life states, and the offline data of the open-circuit voltage-remaining capacity curve was loaded into the battery management system as reference data for the open-circuit voltage-remaining capacity curve. In response to the power-on of the battery management system, when the lithium battery to be evaluated is fully charged, the discharged capacity and open-circuit voltage after a preset time interval are obtained, and the reference remaining capacity and reference open-circuit voltage corresponding to the current lifespan state are obtained based on the discharge capacity and open-circuit voltage-remaining capacity curve reference data. Based on the open-circuit voltage, the reference remaining charge, and the reference open-circuit voltage, determine whether the open-circuit voltage update condition is met, and if the condition is met, convert the open-circuit voltage-remaining charge curve reference data into open-circuit voltage-discharged charge curve data; Based on the open-circuit voltage-discharged charge curve data and the preset discharge weight table, the corresponding open-circuit voltage-remaining charge curve update data is obtained; The open-circuit voltage-remaining power curve update data and the open-circuit voltage-remaining power curve offline data under the current lifespan state are weighted and summed to update the open-circuit voltage-remaining power curve reference data.

[0007] Furthermore, the step of obtaining offline data of the open-circuit voltage-remaining capacity curves of the lithium battery to be evaluated under different lifespan states through offline testing includes: The lithium battery under test, which is of the same type as the lithium battery to be evaluated, is repeatedly charged and discharged according to the first preset charge and discharge rule to obtain the maximum charge amount in the early stage of its lifespan. The first preset charge and discharge rule is to charge the lithium battery under test to the cutoff voltage at a preset rate and maintain the voltage at a constant rate until the current is less than the preset current value. Then, the lithium battery under test is left to stand for a first preset time, and the voltage of the lithium battery under test is discharged to a preset low voltage value at the preset rate. The current discharged amount is recorded. After charging the lithium battery under test to the cutoff voltage at a preset rate and letting it stand for a second preset time to obtain the full-charge open-circuit voltage value, the charging and discharging operation is repeated according to the second preset charging and discharging rule until the remaining capacity is zero, and the offline data of the open-circuit voltage-remaining capacity curve under 100% lifespan is obtained; the second preset charging and discharging rule is to discharge a preset proportion of capacity at the preset rate and then let it stand for the second preset time. According to the third preset charge and discharge rule, the lithium battery under test is repeatedly charged and discharged until a preset number of sets of open circuit voltage-remaining capacity curve offline data for different life states are obtained. The third preset charge and discharge rule is to repeatedly perform charge and discharge operations at a preset rate to obtain the maximum charge amount in the middle stage of the life. After determining that the life state has dropped to the next life state and obtaining the full-charge open circuit voltage value based on the preset life gradient interval, the maximum charge amount in the middle stage of the life, and the maximum charge amount in the early stage of the life, the charge and discharge test is repeatedly performed according to the second preset charge and discharge rule until the remaining capacity is zero, and the open circuit voltage-remaining capacity curve offline data for the corresponding life state is obtained.

[0008] Further, the step of obtaining the reference remaining capacity and reference open-circuit voltage corresponding to the current lifetime state based on the discharged capacity and the open-circuit voltage-remaining capacity curve reference data includes: Based on the current lifespan status, the current sensor error is obtained; Based on the current current sensor error, the discharged power is compensated for the deviation to obtain the calibrated discharged power. Based on the calibration discharge capacity and the open-circuit voltage-remaining capacity curve reference data, the reference remaining capacity and reference open-circuit voltage corresponding to the current lifespan state are obtained.

[0009] Further, the step of obtaining the current current sensor error based on the current lifetime state includes: When the current lifespan is not 100%, the historical current sensor error stored in the battery management system is obtained as the current current sensor error. When the current lifespan is 100%, the first remaining battery capacity value when the battery is fully charged and the second remaining battery capacity value after discharging a preset amount of power are obtained. Based on the first remaining battery capacity value and the second remaining battery capacity value, the current sensor error is calculated, and the current sensor error is filtered to obtain the current current sensor error; the current sensor error is expressed as: in, Indicates the error of the current sensor; and These represent the first remaining battery level and the second remaining battery level, respectively. This indicates the maximum charge amount during the early to mid-life stages. This indicates that a certain amount of electricity has been released.

[0010] Further, the step of obtaining the reference remaining capacity and reference open-circuit voltage corresponding to the current lifetime state based on the calibration discharged capacity and the open-circuit voltage-remaining capacity curve reference data includes: Obtain the maximum charge amount under the current lifespan state, and obtain the reference remaining charge amount based on the maximum charge amount under the current lifespan state and the calibration discharge amount; Based on the reference remaining power, the open-circuit voltage-remaining power curve reference data is found to obtain the corresponding reference open-circuit voltage.

[0011] Further, the step of determining whether the open-circuit voltage update condition is met based on the open-circuit voltage, the reference remaining charge, and the reference open-circuit voltage includes: Based on the open-circuit voltage, the reference open-circuit voltage, and the reference remaining power, it is determined whether the first open-circuit voltage update condition is met; the first open-circuit voltage update condition includes the deviation between the open-circuit voltage and the reference open-circuit voltage reaching a preset deviation threshold, and the reference remaining power not reaching a power threshold; If the first open-circuit voltage update condition is not met, then it is determined that the open-circuit voltage update condition is not met. If the first open-circuit voltage update condition is met, then the corresponding reference discharged capacity is obtained according to the open-circuit voltage, and the remaining capacity deviation is obtained according to the reference discharged capacity and the calibrated discharged capacity. Then, it is determined whether the second open-circuit voltage update condition is met according to the remaining capacity deviation. The second open-circuit voltage update condition includes the remaining capacity deviation being greater than the capacity deviation threshold. If the second open-circuit voltage update condition is met, then the open-circuit voltage update condition is determined to be met; otherwise, the open-circuit voltage update condition is determined not to be met.

[0012] Further, the step of obtaining the corresponding open-circuit voltage-remaining capacity curve update data based on the open-circuit voltage-discharged capacity curve data and the preset discharge weight table includes: The discharge capacity deviation is obtained based on the reference discharge capacity and the calibrated discharge capacity; Based on the calibrated discharge capacity and the preset discharge weight table, the corresponding discharge weight is obtained, and the discharge weight and the discharge capacity deviation are multiplied to obtain the discharge adjustment amount; The difference between the discharged capacity in the open-circuit voltage-discharged capacity curve data and the discharge adjustment amount is used to obtain the corresponding updated value of the remaining capacity. The remaining power update value is normalized to obtain the open circuit voltage-remaining power curve update data.

[0013] Secondly, embodiments of the present invention provide an online updating system for the open-circuit voltage curve of a lithium battery, the system comprising: The offline testing module is used to obtain offline data of the open-circuit voltage-remaining capacity curve of the lithium battery under different life states through offline testing, and to load the offline data of the open-circuit voltage-remaining capacity curve into the battery management system as reference data for the open-circuit voltage-remaining capacity curve. The data acquisition module is used to respond to the power-on of the battery management system, and to acquire the discharged power and open-circuit voltage after a preset time interval when the lithium battery to be evaluated is fully charged. Based on the discharged power and open-circuit voltage-remaining power curve reference data, the module obtains the reference remaining power and reference open-circuit voltage corresponding to the current lifespan state. The data conversion module is used to determine whether the open-circuit voltage update condition is met based on the open-circuit voltage, the reference remaining power, and the reference open-circuit voltage, and when the condition is met, convert the open-circuit voltage-remaining power curve reference data into open-circuit voltage-discharged power curve data. The data update module is used to obtain the corresponding open-circuit voltage-remaining capacity curve update data based on the open-circuit voltage-discharged capacity curve data and the preset discharge weight table; The online correction module is used to perform a weighted summation of the updated open-circuit voltage-remaining power curve data and the offline open-circuit voltage-remaining power curve data under the current lifespan state, and update the reference data of the open-circuit voltage-remaining power curve.

[0014] Thirdly, embodiments of the present invention also provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method.

[0015] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described method.

[0016] This application provides a method, system, computer device, and storage medium for online updating of the open-circuit voltage curve of a lithium battery. The method loads offline data of the open-circuit voltage-remaining capacity curve of the lithium battery under different lifespan states, obtained from offline testing, into a battery management system as reference data for the open-circuit voltage-remaining capacity curve. After the battery management system is powered on, the discharged capacity and open-circuit voltage of the lithium battery under evaluation are obtained at preset time intervals while the battery is fully charged. Based on the discharged capacity and the reference data of the open-circuit voltage-remaining capacity curve, reference remaining capacity and reference open-circuit voltage corresponding to the current lifespan state are obtained. When the open-circuit voltage update condition is met based on the open-circuit voltage, reference remaining capacity, and the reference open-circuit voltage, the reference data of the open-circuit voltage-remaining capacity curve is converted into open-circuit voltage-discharged capacity curve data. After obtaining the corresponding updated data of the open-circuit voltage-remaining capacity curve based on the open-circuit voltage-discharged capacity curve data and a preset discharge weight table, the updated data of the open-circuit voltage-remaining capacity curve and the offline data of the open-circuit voltage-remaining capacity curve under the current lifespan state are weighted and summed to update the reference data of the open-circuit voltage-remaining capacity curve. Compared with existing technologies, this online update method for lithium battery open-circuit voltage curves continuously iterates and updates the open-circuit voltage-remaining capacity curve data obtained from offline measurements under different lifespan conditions and the updated open-circuit voltage-remaining capacity curve data obtained from online updates during static conditions. This method can simply, efficiently, and accurately obtain OCV-SOC curves that conform to the actual situation of the current battery, thereby improving the estimation accuracy of SOC over the entire lifespan and enhancing its application value. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the framework for online updating of the open-circuit voltage curve of a lithium battery in an embodiment of the present invention; Figure 2 This is a flowchart illustrating the online updating method for the open-circuit voltage curve of a lithium battery in an embodiment of the present invention. Figure 3 This is a schematic diagram of the single open-circuit voltage curve update process in the online update method for lithium battery open-circuit voltage curve in this embodiment of the invention; Figure 4 This is a schematic diagram of the open-circuit voltage-remaining charge curve used when correcting the open-circuit voltage in an embodiment of the present invention; Figure 5 It is Figure 4 The diagram shows the open-circuit voltage-remaining charge curve obtained by converting reference data; Figure 6 This is a schematic diagram comparing the calibrated discharge capacity and the reference discharge capacity corresponding to the OCV curves of the lithium manganese iron phosphate hybrid ternary system battery during the BOL period and the MOL period in the embodiments of the present invention. Figure 7 This is a schematic diagram comparing the updated open-circuit voltage-remaining power curve data obtained in an embodiment of the present invention with the corresponding curves of the reference open-circuit voltage-remaining power curve data before the update. Figure 8 This is a schematic diagram of the structure of the online update system for the open-circuit voltage curve of a lithium battery in an embodiment of the present invention; Figure 9 This is an internal structural diagram of the computer device in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and beneficial effects of this application clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described below are only part of the embodiments of the present invention and are used to illustrate the present invention, but are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] The online update method for lithium battery open-circuit voltage curves provided by this invention can be understood as being based on the current situation where existing online OCV update methods are complex and difficult to apply to actual engineering projects. Figure 1 The illustrated online update architecture for lithium battery open-circuit voltage curves uses a weighted average of open-circuit voltage-remaining capacity curve data obtained from offline measurements at different lifespan states and updated open-circuit voltage-remaining capacity curve data obtained from static online updates. This allows for continuous iterative updates of the open-circuit voltage at different lifespan states, resulting in an online update method for the OCV value at different lifespan states. This method is applicable to the online continuous update of OCV for any lithium battery, including lithium manganese iron phosphate hybrid ternary system batteries, and provides reliable assurance for the accuracy of SOC estimation throughout the entire lifespan. The following embodiments will provide a detailed description of the online update method for lithium battery open-circuit voltage curves of this invention.

[0020] In one embodiment, such as Figure 2 As shown, an online method for updating the open-circuit voltage curve of a lithium battery is provided, including the following steps: S11. Obtain offline data of the open-circuit voltage-remaining capacity curves of the lithium battery under different lifespan states through offline testing, and load the offline data of the open-circuit voltage-remaining capacity curves into the battery management system as reference data for the open-circuit voltage-remaining capacity curves; wherein, the offline data of the open-circuit voltage-remaining capacity curves can be understood as OCV-SOC curve data obtained under various preset lifespan states based on offline testing of lithium batteries of the same type as the lithium battery under evaluation according to specific charge and discharge test rules. The specific settings of each preset lifespan state can be determined according to actual application requirements, and are not specifically limited here; specifically, the step of obtaining offline data of the open-circuit voltage-remaining capacity curves of the lithium battery under evaluation under different lifespan states through offline testing includes: The lithium battery under test, which is of the same type as the lithium battery to be evaluated, is repeatedly subjected to charge and discharge tests according to the first preset charge and discharge rule to obtain the maximum charge amount in the early stage of its lifespan. The first preset charge and discharge rule is to charge the lithium battery under test to the cutoff voltage at a preset rate and maintain the voltage at a constant voltage until the current is less than the preset current value. Then, the lithium battery under test is left to stand for a first preset time and discharged to the voltage of the lithium battery under test at the preset rate to a preset low voltage value. The current discharged amount is recorded. The maximum charge amount in the early stage of its lifespan can be understood as the maximum charge amount Qmax_bol when the lifespan state value is 100%. The preset rate, cutoff voltage, preset current value, first preset time, and preset low voltage value in the first preset charge and discharge rule used for the charging test can be adjusted and set according to the type of lithium battery in the actual application. No specific limitation is made here. After charging the lithium battery under test to the cutoff voltage at a preset rate and letting it stand for a second preset time to obtain the fully charged open-circuit voltage value, the charging and discharging operation is repeated according to the second preset charging and discharging rule until the remaining capacity is zero, thus obtaining offline data of the open-circuit voltage-remaining capacity curve under 100% lifespan. The second preset charging and discharging rule is to discharge a preset proportion of capacity at the preset rate and then let it stand for the second preset time. The second preset time and the preset proportion of capacity can be adjusted according to the type of lithium battery in the actual application, and are not specifically limited here. The corresponding offline data of the open-circuit voltage-remaining capacity curve under 100% lifespan can be understood as the remaining capacity and the corresponding open-circuit voltage at each interval from the remaining capacity SOC value of 100% to 0%. The lithium battery under test is repeatedly charged and discharged according to a third preset charge and discharge rule until a preset number of sets of open-circuit voltage-remaining capacity curve offline data for different lifespan states are obtained. The third preset charge and discharge rule is to repeatedly perform charge and discharge operations at a preset rate to obtain the maximum charge amount in the middle stage of the lifespan. After determining that the lifespan state has dropped to the next lifespan state based on the preset lifespan gradient interval, the maximum charge amount in the middle stage of the lifespan, and the maximum charge amount in the early stage of the lifespan, and obtaining the fully charged open-circuit voltage value, the charge and discharge test is repeatedly performed according to the second preset charge and discharge rule until the remaining capacity is zero, and the open-circuit voltage-remaining capacity curve offline data for the corresponding lifespan state is obtained. The preset lifespan gradient interval can be understood as the difference between the SOH values ​​corresponding to two adjacent lifespan states. The maximum charge amount in the middle stage of the lifespan can be understood as the maximum charge amount Qmax_mol corresponding to each middle lifespan state value.

[0021] The following section uses lithium manganese iron phosphate batteries as an example to explain the above offline testing process in detail: 1. At room temperature, charge the lithium battery under test in the early stage of life (beginning of life, bol) at a 1C rate to the cutoff voltage of 4.3V, and keep the voltage constant until the current is less than 0.05C; 2. Let stand for 30 minutes; 3. Discharge the battery voltage to 2.0V at a 1C rate and record the discharged charge Q0; 4. Let stand for 30 minutes; 5. Repeat the above steps 3 times, and average the Q0 values ​​from the 3 times to obtain the maximum charge capacity Qmax_bol at the beginning of the battery's lifespan; 6. Recharge the battery using step 1; 7. After standing for 2 hours, record the voltage and its OCV value at 100% SOC; 8. After discharging 5% of the charge with a 1C current, let it stand for 2 hours and record the voltage to obtain the OCV value at 95% SOC; 9. Repeat step 8 until SOC=0%, and obtain the OCV-SOC curve data at the initial bol (i.e. SOH=100%) of the battery life (the horizontal axis is from 100% to 0%, with a preset proportional capacity interval of 5%, and the vertical axis is the recorded OCV value). 10. Charge and discharge the battery at a 1C rate at room temperature; 11. Repeat step 10 500 times, that is, 500 loops; 12. Measure the maximum charge amount Qmax_mol in the middle of life (mol) stage of the battery using the method in steps 1-3, and divide it by the maximum charge amount Qmax_bol in the early stage of life to obtain the current SOH value of the battery (SOH = Qmax_mol / Qmax_bol*100%). Based on the obtained SOH value, determine when the battery will drop to the next life state, and then measure the OCV-SOC curve data corresponding to the current life state using the test method in steps 8-9. 13. Repeat steps 11-12 until SOH <= 70%, and you will get the OCV-SOC curve data table shown in Table 1 as SOH changes.

[0022] Table 1. OCV-SOC curves for different SOH states. It should be noted that Table 1 above is based on offline open-circuit voltage-remaining capacity curve data of lithium manganese iron phosphate batteries, with SOH decreasing from 100% to 70% at 5% intervals, corresponding to various lifespan states. In practical applications, the relevant parameter values ​​in the above test process can be adjusted according to the lithium battery type and the lifespan state monitoring range to obtain the corresponding offline open-circuit voltage-remaining capacity curve data.

[0023] The offline open-circuit voltage-remaining charge curve data obtained under different lifespan states through the above test methods are written into the BMS. This allows the BMS to perform calculations based on the offline open-circuit voltage-remaining charge curve data after power-on. Figure 3 The update process shown performs online updates of the open-circuit voltage under different lifespan conditions.

[0024] S12. In response to the power-on of the battery management system, when the lithium battery to be evaluated is fully charged, the discharged capacity and open-circuit voltage after a preset time interval are obtained, and the reference remaining capacity and reference open-circuit voltage corresponding to the current lifespan state are obtained based on the discharge capacity and the open-circuit voltage-remaining capacity curve reference data; wherein, the preset time interval can be understood as the resting time used for discharge quantity statistics after the lithium battery to be evaluated is fully charged, and can be selected according to actual application requirements. For example, when the ambient temperature is >25℃, the preset time interval is set to 2 hours, that is, the resting time exceeds 2 hours, and the corresponding discharged capacity Q_dsg and open-circuit voltage OCV_new can be obtained; In principle, after obtaining the discharged power and open-circuit voltage, the reference remaining power and reference open-circuit voltage corresponding to the open-circuit voltage-remaining power curve reference data can be directly obtained from the discharged power, and it can be used to determine whether the open-circuit voltage value needs to be updated. However, considering the sensor error that exists in the actual power statistics process, this embodiment preferably corrects the obtained discharged power based on the current sensor error before use, so as to improve the accuracy of obtaining the reference remaining power and reference open-circuit voltage. Specifically, the step of obtaining the reference remaining power and reference open-circuit voltage corresponding to the current lifespan state based on the discharged power and the open-circuit voltage-remaining power curve reference data includes: Based on the current lifespan state, the current current sensor error is obtained; where the current lifespan state can be understood as the State of Health (SOH) value of the battery recorded by the BMS; correspondingly, the current current sensor error can be understood as the current sensor error that needs to be referenced under the current lifespan state. Given the slow change of the OCV-SOC curve and its tendency to remain relatively constant over a short period, to ensure the simplicity and efficiency of the online update process, this embodiment preferably calculates the sensor error when SOH = 100% and stores it in the BMS. Subsequent processing directly uses this value without further updates. Specifically, the step of obtaining the current current sensor error based on the current lifespan state includes: When the current lifespan is not 100%, the historical current sensor error stored in the battery management system is obtained as the current current sensor error. When the current lifespan is 100%, the first remaining power value when the battery is fully charged and the second remaining power value after discharging a preset amount of power are obtained. Based on the first remaining power value and the second remaining power value, the current sensor error is calculated and the current sensor error is filtered to obtain the current current sensor error. When the current lifespan is 100%, the specific process of obtaining the current current sensor error can be understood as follows: 1) After the battery is fully charged or after OCV correction, the first SOC point and the first remaining charge value SOC1 are obtained; when fully charged, SOC1=100%, and SOC1 is obtained based on the current OCV value and the open circuit voltage-remaining charge curve reference data, that is, the SOC value is obtained through the OCV-SOC curve reference data when SOH=100%; 2) After the preset power dQ is released and OCV correction occurs again, the second remaining power value SOC2 at the second SOC point is obtained; SOC2 is obtained based on the current OCV value and the open circuit voltage-remaining power curve reference data, that is, the corresponding SOC value is obtained through the OCV-SOC curve reference data when SOH=100%.

[0025] 3) First calculate the current sensor error using the following formula: in, Indicates the error of the current sensor; and These represent the first remaining battery level and the second remaining battery level, respectively. This indicates the maximum charge amount during the early to mid-life stages. Indicates the amount of electricity discharged; 4) The obtained current sensor error is then filtered as follows: in, The error value obtained in step (3) before filtering; Indicates the process The current sensor error obtained from round-by-round iterative filtering; Indicates the filtering process -1 round of iterations to obtain the current sensor error prediction value.

[0026] Based on the current sensor error, the discharged power is compensated for the deviation to obtain the calibrated discharged power; wherein, the calibrated discharged power is expressed as: In the formula, and These represent the calibration discharge capacity and the discharge capacity, respectively. This indicates the current current sensor error; Based on the calibrated discharged capacity and the open-circuit voltage-remaining capacity curve reference data, the reference remaining capacity and reference open-circuit voltage corresponding to the current lifetime state are obtained; wherein, the reference remaining capacity and reference open-circuit voltage can be understood as the remaining capacity and open-circuit voltage corresponding to the calibrated discharged capacity on the open-circuit voltage-remaining capacity curve reference data; specifically, the step of obtaining the reference remaining capacity and reference open-circuit voltage corresponding to the current lifetime state based on the calibrated discharged capacity and the open-circuit voltage-remaining capacity curve reference data includes: Obtain the maximum charge level under the current lifespan state, and calculate the reference remaining charge level based on the maximum charge level and the calibrated discharge capacity; wherein, the reference remaining charge level is expressed as: SOC_old = Q_dsg_cal / Qmax Wherein, SOC_old represents the reference remaining power; Q_dsg_cal represents the calibration discharge power; Qmax represents the maximum state charge in the current lifetime state, which is obtained by multiplying the current lifetime state SOH value by the maximum charge in the early lifetime state Qmax_bol; Based on the reference remaining power, the open-circuit voltage-remaining power curve reference data is found to obtain the corresponding reference open-circuit voltage; wherein, the reference open-circuit voltage is expressed as: in, Indicates the reference open-circuit voltage; It is represented as an open-circuit voltage-remaining charge curve function.

[0027] In principle, the open-circuit voltage can be directly updated based on the open-circuit voltage, reference remaining charge, and reference open-circuit voltage obtained above. However, considering the system processing efficiency and resource consumption costs in practical applications, this embodiment preferably sets certain update conditions according to the following method to reduce the update frequency in practical applications, save data processing costs, and improve processing efficiency.

[0028] S13. Based on the open-circuit voltage, the reference remaining power, and the reference open-circuit voltage, determine whether the open-circuit voltage update condition is met, and if it is determined that it is met, convert the open-circuit voltage-remaining power curve reference data into open-circuit voltage-discharged power curve data; wherein, the open-circuit voltage update condition can be understood as a detection condition designed based on the magnitude of the open-circuit voltage deviation and the range to which the reference remaining power belongs to confirm whether to enter the subsequent update process; specifically, the step of determining whether the open-circuit voltage update condition is met based on the open-circuit voltage, the reference remaining power, and the reference open-circuit voltage includes: Based on the open-circuit voltage, the reference open-circuit voltage, and the reference remaining power, it is determined whether the first open-circuit voltage update condition is met. The first open-circuit voltage update condition includes the deviation between the open-circuit voltage and the reference open-circuit voltage reaching a preset deviation threshold, and the reference remaining power not reaching a power threshold. The preset deviation threshold and the power threshold can be selected according to actual application requirements. Here, it is preferred to set the preset deviation threshold to 100mV and the power threshold to 65%. That is, when the deviation between the open-circuit voltage OCV_new and the reference open-circuit voltage OCV_old is less than 100mV, or when the reference remaining power SOC_old > 65%, the update is directly terminated. If the first open-circuit voltage update condition is not met, then it is determined that the open-circuit voltage update condition is not met. If the first open-circuit voltage update condition is met, then based on the open-circuit voltage, the corresponding reference discharged capacity is obtained, and based on the reference discharged capacity and the calibrated discharged capacity, the remaining capacity deviation is obtained. Based on the remaining capacity deviation, it is determined whether the second open-circuit voltage update condition is met. The second open-circuit voltage update condition includes a remaining capacity deviation greater than a capacity deviation threshold. The capacity deviation threshold can be selected according to actual application requirements and is not specifically limited here. The process of determining whether the second open-circuit voltage update condition is met can be understood as follows: First, calculate the power deviation threshold using the following formula: ΔSOC=(Q_dsg_false–Q_dsg_cal) / Qmax*100% When ΔSOC <= 2%, no further update processing is performed; otherwise, the subsequent OCV curve update operation continues. If the second open-circuit voltage update condition is met, then the open-circuit voltage update condition is determined to be met; otherwise, the open-circuit voltage update condition is determined not to be met.

[0029] This embodiment reduces the update frequency in practical applications by setting the detection of open-circuit voltage update conditions and executing the subsequent update process only after determining that the update conditions are met, thereby effectively saving system processing resources and improving processing efficiency.

[0030] The above open-circuit voltage-discharged capacity curve data can be understood as curve data obtained by multiplying the horizontal axis SOC of the open-circuit voltage-remaining capacity curve reference data by the corresponding maximum charging capacity. For example, it can be... Figure 4 The open-circuit voltage-remaining charge curve reference data shown is converted to Figure 5 The open-circuit voltage-discharge curve is shown.

[0031] S14. Based on the open-circuit voltage-discharged capacity curve data and the preset discharge weight table, obtain the corresponding open-circuit voltage-remaining capacity curve update data; wherein, the preset discharge weight table can be understood as determining the weight of the discharged capacity according to the position relationship between the open-circuit voltage corresponding to the discharged capacity on the open-circuit voltage-discharged capacity curve and the currently obtained open-circuit voltage. Preferably, the weight of the horizontal coordinate (discharged capacity) closest to the currently obtained open-circuit voltage OCV_new is set to 0.8, the weight of the two points before and after this horizontal coordinate (a total of four points) is set to 0.3, and the weight of other coordinate points is set to 0. For example, assuming the cell capacity is 100AH, and the Q_dsg_cal corresponding to the open-circuit voltage OCV_new is 75AH (then its nearest coordinate point is 25%SOC, with a weight of 0.8, and the weight of the four points before and after it is set to 0.3); based on this rule, the preset discharge weight table as shown in Table 2 can be obtained: Table 2 Preset Discharge Weight Table Based on the above-mentioned preset discharge weight table, and Figure 6 The reference discharged capacity Q_dsg_false and the calibrated discharged capacity Q_dsg_cal corresponding to the actual open-circuit voltage OCV_new shown can be used to correct the discharged capacity in the obtained open-circuit voltage-discharged capacity curve data, making the curve data closer to reality. Specifically, the step of obtaining the corresponding open-circuit voltage-remaining capacity curve update data based on the open-circuit voltage-discharged capacity curve data and the preset discharge weight table includes: The discharge capacity deviation is obtained based on the reference discharge capacity and the calibrated discharge capacity; wherein, the discharge capacity deviation is understood as the difference between the reference discharge capacity and the calibrated discharge capacity, i.e.: Q_dsg_false – Q_dsg_cal; Based on the calibrated discharge capacity and the preset discharge weight table, the corresponding discharge weight is obtained, and the discharge weight and the discharge capacity deviation are productted to obtain the discharge adjustment amount; wherein, the discharge adjustment amount can be expressed as: Q_adjust=(Q_dsg_false–Q_dsg_cal)*w In the formula, Q_adjust represents the discharge adjustment amount; Q_dsg_false and Q_dsg_cal represent the reference discharge amount and the calibrated discharge amount, respectively; w represents the discharge weight corresponding to the calibrated discharge amount; The difference between the discharged capacity in the open-circuit voltage-discharged capacity curve data and the discharge adjustment amount is used to obtain the corresponding updated value of the remaining capacity. The remaining power update value is normalized to obtain the open-circuit voltage-remaining power curve update data; wherein, the open-circuit voltage-remaining power curve update data can be understood as the reference data of the open-circuit voltage-remaining power curve being corrected based on the open-circuit voltage OCV_new, as shown in Table 3. Figure 7 The updated data on the OCV-SOC1 curve will be used for subsequent fusion with offline data of the curve under the corresponding lifetime state.

[0032] Table 3 shows the OCV data obtained from online updates. S15. The open-circuit voltage-remaining power curve update data and the open-circuit voltage-remaining power curve offline data under the current lifespan state are weighted and summed to update the open-circuit voltage-remaining power curve reference data; wherein, the open-circuit voltage-remaining power curve offline data under the current lifespan state is the data on the curve OCV-SOC2 obtained from the initial offline test based on the SOH value under the current lifespan state. For example, if the current SOH=95%, the corresponding OCV data can be obtained as shown in Table 4. Table 4 shows the OCV data obtained from SOH. The specific process of updating the open-circuit voltage-remaining capacity curve reference data based on the obtained open-circuit voltage-remaining capacity curve update data and the offline open-circuit voltage-remaining capacity curve data under the current lifespan can be understood as follows: The OCV values ​​on the OCV-SOC1 and OCV-SOC2 curves are weighted and summed according to preset curve weights to obtain a new OCV value, which is then used to replace the OCV value in the open-circuit voltage-remaining capacity curve reference data. That is, the updated open-circuit voltage-remaining capacity curve reference data can be represented as: OCV-SOC_new = OCV-SOC1*W1+ OCV-SOC2*W2 Wherein, OCV-SOC_new represents the updated open-circuit voltage-remaining power curve reference data; W1 and W2 represent the weighted values ​​corresponding to the preset updated open-circuit voltage-remaining power curve data and the offline open-circuit voltage-remaining power curve data under the current lifespan state, respectively. They can be selected according to actual application requirements. In this embodiment, W1 and W2 are both set to 0.5, that is, the corresponding OCV values ​​in Table 3 and Table 4 are added together and averaged to obtain the final updated open-circuit voltage-remaining power curve reference data as shown in Table 5.

[0033] Table 5. Updated OCV curves It should be noted that the above method steps can be understood as an open-circuit voltage curve update process within the life cycle of the lithium battery to be evaluated. Subsequently, based on the updated open-circuit voltage-remaining capacity curve reference data, the open-circuit voltage under the next life state will continue to be iteratively updated.

[0034] This application embodiment provides offline data of the open-circuit voltage-remaining capacity curves of the lithium battery under different lifespan states obtained from offline testing, which is loaded into the battery management system as reference data for the open-circuit voltage-remaining capacity curve. After the battery management system is powered on, the discharged capacity and open-circuit voltage are obtained after a preset time interval when the lithium battery under evaluation is fully charged. Based on the discharged capacity and open-circuit voltage-remaining capacity curve reference data, the reference remaining capacity and reference open-circuit voltage corresponding to the current lifespan state are obtained. When it is determined that the open-circuit voltage update condition is met based on the open-circuit voltage, reference remaining capacity, and the reference open-circuit voltage, the open-circuit voltage-remaining capacity curve reference data is converted into open-circuit voltage-discharged capacity curve data. The technical solution involves obtaining the corresponding open-circuit voltage-remaining capacity curve update data from online data and a preset discharge weight table. This update data is then weighted and summed with the offline open-circuit voltage-remaining capacity curve data under the current lifespan condition to update the reference data. This method, which continuously iterates and updates the open-circuit voltage under different lifespan conditions by weighting the offline open-circuit voltage-remaining capacity curve data obtained from online updates, can simply, efficiently, and accurately acquire the OCV-SOC curve that matches the actual state of the battery. This improves the estimation accuracy of SOC throughout the entire lifespan and has high application value.

[0035] It should be noted that although the steps in the flowchart above are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order requirement for the execution of these steps, and they can be executed in other orders.

[0036] In one embodiment, such as Figure 8 As shown, an online update system for the open-circuit voltage curve of a lithium battery is provided, the system comprising: Offline testing module 1 is used to obtain offline data of the open circuit voltage-remaining capacity curve of the lithium battery to be evaluated under different life states through offline testing, and load the offline data of the open circuit voltage-remaining capacity curve into the battery management system as reference data of the open circuit voltage-remaining capacity curve. Data acquisition module 2 is used to respond to the power-on of the battery management system, and in the fully charged state of the lithium battery to be evaluated, to acquire the discharged power and open circuit voltage after a preset time interval, and to obtain the reference remaining power and reference open circuit voltage corresponding to the current life state based on the discharged power and open circuit voltage-remaining power curve reference data. Data conversion module 3 is used to determine whether the open-circuit voltage update condition is met based on the open-circuit voltage, the reference remaining power, and the reference open-circuit voltage, and when the condition is met, convert the open-circuit voltage-remaining power curve reference data into open-circuit voltage-discharged power curve data; Data update module 4 is used to obtain corresponding open-circuit voltage-remaining power curve update data based on the open-circuit voltage-discharged power curve data and the preset discharge weight table; The online correction module 5 is used to perform a weighted summation of the updated open-circuit voltage-remaining power curve data and the offline open-circuit voltage-remaining power curve data under the current lifespan state, and update the open-circuit voltage-remaining power curve reference data.

[0037] Specific limitations regarding the online update system for lithium battery open-circuit voltage curves can be found in the limitations of the online update method for lithium battery open-circuit voltage curves described above; the corresponding technical effects are equivalent and will not be repeated here. Each module in the aforementioned online update system for lithium battery open-circuit voltage curves can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0038] Figure 9 An internal structural diagram of a computer device is shown in one embodiment. This computer device may specifically be a terminal or a server. Figure 9 As shown, the computer device includes a processor, memory, network interface, display, camera, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for online updating of the open-circuit voltage curve of a lithium battery. The display screen can be an LCD screen or an e-ink display screen. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad mounted on the computer device casing, or an external keyboard, touchpad, or mouse.

[0039] Those skilled in the art will understand that Figure 9The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computing devices may include more or fewer components than those shown in the figure, or combine certain components, or have the same component arrangement.

[0040] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0041] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0042] In summary, the present invention provides a method and system for online updating of the open-circuit voltage curve of a lithium battery. The method loads offline data of the open-circuit voltage-remaining capacity curve of the lithium battery under different lifespan states obtained from offline testing into the battery management system as reference data for the open-circuit voltage-remaining capacity curve. After the battery management system is powered on, the discharged capacity and open-circuit voltage are obtained at preset time intervals while the lithium battery under evaluation is fully charged. Based on the discharged capacity and the open-circuit voltage-remaining capacity curve reference data, reference remaining capacity and reference open-circuit voltage corresponding to the current lifespan state are obtained. When the open-circuit voltage update condition is met based on the open-circuit voltage, reference remaining capacity, and the reference open-circuit voltage, the open-circuit voltage-remaining capacity curve reference data is converted into open-circuit voltage-discharge capacity curve reference data. This method involves measuring open-circuit voltage-remaining capacity curve data, obtaining corresponding open-circuit voltage-remaining capacity curve update data based on open-circuit voltage-discharged capacity curve data and a preset discharge weight table, and then weighting and summing the updated open-circuit voltage-remaining capacity curve data with offline open-circuit voltage-remaining capacity curve data under the current lifespan state to update the reference data of the open-circuit voltage-remaining capacity curve. This method continuously iterates and updates the open-circuit voltage under different lifespan states by weighting and averaging the measured open-circuit voltage-remaining capacity curve data under different lifespan states with the updated open-circuit voltage-remaining capacity curve data obtained by static online updates. This method can simply, efficiently, and accurately obtain the OCV-SOC curve that conforms to the actual situation of the current battery, thereby improving the estimation accuracy of SOC over the entire lifespan and has high application value.

[0043] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0044] The embodiments described above are merely preferred embodiments of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the technical principles of this invention, and these improvements and substitutions should also be considered within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the scope of the claims.

Claims

1. A method for online updating of the open-circuit voltage curve of a lithium battery, characterized in that, The method includes the following steps: Offline testing was conducted to obtain offline data of the open-circuit voltage-remaining capacity curve of the lithium battery under different life states, and the offline data of the open-circuit voltage-remaining capacity curve was loaded into the battery management system as reference data for the open-circuit voltage-remaining capacity curve. In response to the power-on of the battery management system, when the lithium battery to be evaluated is fully charged, the discharged capacity and open-circuit voltage after a preset time interval are obtained, and the reference remaining capacity and reference open-circuit voltage corresponding to the current lifespan state are obtained based on the discharge capacity and open-circuit voltage-remaining capacity curve reference data. Based on the open-circuit voltage, the reference remaining charge, and the reference open-circuit voltage, determine whether the open-circuit voltage update condition is met, and if the condition is met, convert the open-circuit voltage-remaining charge curve reference data into open-circuit voltage-discharged charge curve data; Based on the open-circuit voltage-discharged charge curve data and the preset discharge weight table, the corresponding open-circuit voltage-remaining charge curve update data is obtained; The open-circuit voltage-remaining power curve update data and the open-circuit voltage-remaining power curve offline data under the current lifespan state are weighted and summed to update the open-circuit voltage-remaining power curve reference data.

2. The online updating method for the open-circuit voltage curve of a lithium battery as described in claim 1, characterized in that, The step of obtaining offline data of the open-circuit voltage-remaining capacity curves of the lithium battery to be evaluated under different lifespan states through offline testing includes: The lithium battery under test, which is of the same type as the lithium battery to be evaluated, is repeatedly charged and discharged according to the first preset charge and discharge rule to obtain the maximum charge amount in the early stage of its lifespan. The first preset charge and discharge rule is to charge the lithium battery under test to the cutoff voltage at a preset rate and maintain the voltage at a constant rate until the current is less than the preset current value. Then, the lithium battery under test is left to stand for a first preset time, and the voltage of the lithium battery under test is discharged to a preset low voltage value at the preset rate. The current discharged amount is recorded. After charging the lithium battery under test to the cutoff voltage at a preset rate and letting it stand for a second preset time to obtain the full-charge open-circuit voltage value, the lithium battery under test is repeatedly charged and discharged according to the second preset charge and discharge rule until the remaining capacity is zero, and the offline data of the open-circuit voltage-remaining capacity curve under 100% lifespan is obtained; the second preset charge and discharge rule is to discharge a preset proportion of capacity at the preset rate and then let it stand for the second preset time. According to the third preset charge and discharge rule, the lithium battery under test is repeatedly charged and discharged until a preset number of sets of open circuit voltage-remaining capacity curve offline data for different life states are obtained. The third preset charge and discharge rule is to repeatedly perform charge and discharge operations at a preset rate to obtain the maximum charge amount in the middle stage of the life. After determining that the life state has dropped to the next life state and obtaining the full-charge open circuit voltage value based on the preset life gradient interval, the maximum charge amount in the middle stage of the life, and the maximum charge amount in the early stage of the life, the charge and discharge test is repeatedly performed according to the second preset charge and discharge rule until the remaining capacity is zero, and the open circuit voltage-remaining capacity curve offline data for the corresponding life state is obtained.

3. The online updating method for the open-circuit voltage curve of a lithium battery as described in claim 1, characterized in that, The step of obtaining the reference remaining capacity and reference open-circuit voltage corresponding to the current lifetime state based on the discharged capacity and the open-circuit voltage-remaining capacity curve reference data includes: Based on the current lifespan status, the current sensor error is obtained; Based on the current current sensor error, the discharged power is compensated for the deviation to obtain the calibrated discharged power. Based on the calibration discharge capacity and the open-circuit voltage-remaining capacity curve reference data, the reference remaining capacity and reference open-circuit voltage corresponding to the current lifespan state are obtained.

4. The online updating method for the open-circuit voltage curve of a lithium battery as described in claim 3, characterized in that, The step of obtaining the current current sensor error based on the current lifespan status includes: When the current lifespan is not 100%, the historical current sensor error stored in the battery management system is used as the current current sensor error. When the current lifespan is 100%, the first remaining battery capacity value when the battery is fully charged and the second remaining battery capacity value after discharging a preset amount of power are obtained. Based on the first remaining battery capacity value and the second remaining battery capacity value, the current sensor error is calculated, and the current sensor error is filtered to obtain the current current sensor error; the current sensor error is expressed as: Among them, Err I The current sensor error is represented by: soc1 and soc2, which represent the first and second remaining charge values, respectively; Qmax_bol, which represents the maximum charge amount during the early and middle stages of the lifespan; and dQ, which represents the discharged charge.

5. The online updating method for the open-circuit voltage curve of a lithium battery as described in claim 3, characterized in that, The step of obtaining the reference remaining capacity and reference open-circuit voltage corresponding to the current lifetime state based on the calibration discharged capacity and the open-circuit voltage-remaining capacity curve reference data includes: Obtain the maximum charge amount under the current lifespan state, and obtain the reference remaining charge amount based on the maximum charge amount under the current lifespan state and the calibration discharge amount; Based on the reference remaining power, the open-circuit voltage-remaining power curve reference data is found to obtain the corresponding reference open-circuit voltage.

6. The online updating method for the open-circuit voltage curve of a lithium battery as described in claim 5, characterized in that, The step of determining whether the open-circuit voltage update condition is met based on the open-circuit voltage, the reference remaining charge, and the reference open-circuit voltage includes: Based on the open-circuit voltage, the reference open-circuit voltage, and the reference remaining power, it is determined whether the first open-circuit voltage update condition is met; the first open-circuit voltage update condition includes the deviation between the open-circuit voltage and the reference open-circuit voltage reaching a preset deviation threshold, and the reference remaining power not reaching a power threshold; If the first open-circuit voltage update condition is not met, then it is determined that the open-circuit voltage update condition is not met. If the first open-circuit voltage update condition is met, then the corresponding reference discharged capacity is obtained according to the open-circuit voltage, and the remaining capacity deviation is obtained according to the reference discharged capacity and the calibrated discharged capacity. Then, it is determined whether the second open-circuit voltage update condition is met according to the remaining capacity deviation. The second open-circuit voltage update condition includes the remaining capacity deviation being greater than the capacity deviation threshold. If the second open-circuit voltage update condition is met, then the open-circuit voltage update condition is determined to be met; otherwise, the open-circuit voltage update condition is determined not to be met.

7. The online updating method for the open-circuit voltage curve of a lithium battery as described in claim 6, characterized in that, The step of obtaining the corresponding open-circuit voltage-remaining capacity curve update data based on the open-circuit voltage-discharged capacity curve data and the preset discharge weight table includes: The discharge capacity deviation is obtained based on the reference discharge capacity and the calibrated discharge capacity; Based on the calibrated discharge capacity and the preset discharge weight table, the corresponding discharge weight is obtained, and the discharge weight and the discharge capacity deviation are multiplied to obtain the discharge adjustment amount; The difference between the discharged capacity in the open-circuit voltage-discharged capacity curve data and the discharge adjustment amount is used to obtain the corresponding updated value of the remaining capacity. The remaining power update value is normalized to obtain the open circuit voltage-remaining power curve update data.

8. A lithium battery open-circuit voltage curve online updating system, characterized in that, The system includes: The offline testing module is used to obtain offline data of the open-circuit voltage-remaining capacity curve of the lithium battery under different life states through offline testing, and to load the offline data of the open-circuit voltage-remaining capacity curve into the battery management system as reference data for the open-circuit voltage-remaining capacity curve. The data acquisition module is used to respond to the power-on of the battery management system, and to acquire the discharged power and open-circuit voltage after a preset time interval when the lithium battery to be evaluated is fully charged. Based on the discharged power and open-circuit voltage-remaining power curve reference data, the module obtains the reference remaining power and reference open-circuit voltage corresponding to the current lifespan state. The data conversion module is used to determine whether the open-circuit voltage update condition is met based on the open-circuit voltage, the reference remaining power, and the reference open-circuit voltage, and when the condition is met, convert the open-circuit voltage-remaining power curve reference data into open-circuit voltage-discharged power curve data. The data update module is used to obtain the corresponding open-circuit voltage-remaining capacity curve update data based on the open-circuit voltage-discharged capacity curve data and the preset discharge weight table; The online correction module is used to perform a weighted summation of the updated open-circuit voltage-remaining power curve data and the offline open-circuit voltage-remaining power curve data under the current lifespan state, and update the reference data of the open-circuit voltage-remaining power curve.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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