A current error adaptive calculation method and system

Abstract

The application provides a current error adaptive calculation method and system, and relates to the technical field of energy storage batteries. The method comprises the following steps: obtaining a theoretical current zero drift error value according to an SOC deviation value, a battery rated capacity and an effective current time statistical value; obtaining a current zero drift correction increment of this time according to the theoretical current zero drift error value and a preset proportion coefficient; limiting the amplitude in a preset correction range according to a last current zero drift correction value and the current zero drift correction increment of this time to obtain an updated current zero drift correction value; and obtaining a corrected ampere-hour integral current value according to an original sampling current and the updated current zero drift correction value. The application avoids the cost and complexity problems caused by temperature sampling error accumulation or hardware redundancy in the prior art.

Description

Technical Field

[0001] This application relates to the field of energy storage battery technology, and in particular to an adaptive current error calculation method and system. Background Technology

[0002] In electrochemical energy storage systems, the battery management system typically receives DC-side current collected by the power conversion system, performs ampere-hour integration based on this current data, and estimates the battery's state of charge (SOC) by combining this data with cell voltage characteristics. Existing SOC estimation methods mainly include open-circuit voltage correction, full charge / discharge correction, dynamic voltage correction, and ampere-hour integration. Their basic framework is to periodically correct the SOC based on ampere-hour integration and changes in cell voltage.

[0003] However, in actual operating conditions, the current sampling process commonly suffers from inaccurate zero-drift bias, meaning that the sampled DC-side current has a fixed offset relative to the actual current. Under these conditions, since ampere-hour integration is a time-cumulative calculation of the current, the small current error caused by zero-drift bias accumulates continuously with the extension of charging and discharging time, causing the difference between the SOC obtained by ampere-hour integration and the actual SOC of the battery to become increasingly larger. Even if subsequent correction events such as full charge, full discharge, or dynamic voltage are triggered by cell voltage to bring the SOC back to the accurate value, the integration error caused by zero-drift bias cannot be eliminated in the entire interval before the next correction. This leads to a continuous deterioration in the accuracy of SOC estimation under low-current and long-term operating conditions, affecting the energy management and safe dispatch of the energy storage system.

[0004] Existing technologies for correcting current drift mostly rely on offline temperature drift modeling, redundant design of dual current sampling loops, or comparison with external reference currents. The former is limited by the accumulation of temperature sampling errors and incomplete coverage of operating conditions, while the latter two require additional hardware sampling loops and circuit structures, leading to increased implementation costs and system complexity. It is difficult to solve the SOC estimation error problem caused by zero drift bias in existing single-branch sampling energy storage systems at low cost. Summary of the Invention

[0005] This application provides an adaptive current error calculation method and system, which avoids the cost and complexity problems caused by the accumulation of temperature sampling errors or hardware redundancy in the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution of this application is as follows: In a first aspect, an adaptive current error calculation method is applied to the battery management system of an energy storage system, the method comprising the following steps: Based on the voltage correction event triggered when the cell voltage reaches the preset correction condition, the current state-of-charge (SOC) reference value and the preset correction range near the correction point are obtained. Based on the SOC integral value before the next correction obtained by ampere-hour integration and the SOC benchmark value, the SOC deviation value is obtained under the condition that no other correction is triggered outside the preset correction interval between two adjacent corrections. The effective current time statistics are obtained based on the effective current duration between two adjacent corrections where the DC side current amplitude exceeds the preset filtering threshold. Based on the SOC deviation value, the battery rated capacity, and the effective current time statistics, the theoretical current zero drift error value is obtained. Based on the theoretical current zero drift error value and the preset proportional coefficient, the current zero drift correction increment is obtained. Based on the previous current zero drift correction value and the current current zero drift correction increment, the amplitude is limited within the preset correction range to obtain the updated current zero drift correction value. Based on the original sampled current and the updated current zero-drift correction value, the corrected ampere-hour integral current value is obtained.

[0007] Secondly, an adaptive current error calculation system includes: The voltage correction module is used to obtain the current accurate SOC reference value and the preset correction range near the correction point based on the voltage correction event triggered when the cell voltage reaches the preset correction condition. The deviation calculation module is used to obtain the SOC deviation value based on the SOC integral value before the next correction obtained by ampere-hour integration and the SOC reference value, provided that no other correction is triggered outside the preset correction interval between two adjacent corrections. The time statistics module is used to obtain the effective current time statistics value based on the effective current duration between two adjacent corrections where the DC side current amplitude exceeds the preset filtering threshold. The error estimation module is used to obtain the theoretical current zero drift error value based on the SOC deviation value, the battery rated capacity, and the effective current time statistics. The incremental calculation module is used to obtain the current zero drift correction increment based on the theoretical current zero drift error value and the preset proportional coefficient. The correction and update module is used to limit the current zero drift correction value within a preset correction range based on the previous current zero drift correction value and the current current zero drift correction increment, and obtain the updated current zero drift correction value. The current output module is used to obtain the corrected ampere-hour integrated current value based on the original sampled current and the updated current zero drift correction value.

[0008] The above-described solution in this application includes at least the following beneficial effects: This application uses the SOC reference value obtained from the voltage correction event triggered by the cell voltage as a reliable anchor point. It uses the difference between the SOC integral value accumulated by ampere-hour integration between two adjacent corrections and the SOC reference value under the condition that no other corrections are triggered outside the preset correction interval as the SOC deviation value. This deviation value is quantitatively characterized as the integral error of zero drift bias accumulated between two corrections. Thus, without relying on the temperature model or adding redundant sampling loops, the current zero drift error can be directly deduced from the SOC correction result, avoiding the cost and complexity problems caused by the accumulation of temperature sampling errors or hardware redundancy in the prior art.

[0009] This application further obtains the effective current time statistics based on the effective current duration between two corrections where the amplitude exceeds the preset filtering threshold, and calculates the theoretical current zero drift error value together with the SOC deviation value and the battery rated capacity. This ensures that the estimation of the zero drift error is based only on the current period that actually participates in the effective integration, eliminating the interference of small current periods not included in the statistics on zero drift identification and improving the accuracy of zero drift error identification.

[0010] This application optimizes the theoretical current zero-drift error value using a preset proportional coefficient to obtain the current zero-drift correction increment. Within a preset correction range, it accumulates and limits the correction values ​​from previous iterations to obtain an updated current zero-drift correction value to compensate for the original sampled current. This forms a progressive and constrained adaptive correction mechanism that can gradually approach the true zero-drift value with multiple corrections while avoiding oscillations and divergences caused by a single overcorrection. As a result, it continuously reduces the current error of the ampere-hour integral under inaccurate zero-drift bias conditions, significantly improving the accuracy and stability of SOC estimation under long-term operation and low-current conditions. Attached Figure Description

[0011] Figure 1 This is a flowchart illustrating an adaptive current error calculation method provided in an embodiment of this application.

[0012] Figure 2 This is a schematic diagram of an adaptive current error calculation system architecture provided by an embodiment of this application.

[0013] Figure 3 This is a flowchart illustrating the steps of obtaining the SOC reference value and the preset correction range based on a voltage correction event, as described in this application. Detailed Implementation

[0014] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0015] It should be noted that the battery management system involved in this embodiment is deployed in the electrochemical energy storage system. This battery management system is communicatively connected to the power conversion system. The power conversion system collects the DC-side current of the energy storage battery cluster and transmits this current data to the battery management system. The battery management system performs ampere-hour integration based on this current data to estimate the battery's state of charge. The adaptive current error calculation method described in this embodiment runs within this battery management system and is used to identify and adaptively correct the zero-drift bias present in the current sampling stage.

[0016] Example 1 This embodiment provides an adaptive current error calculation method, referring to... Figure 1 As shown, the method includes the following steps.

[0017] Step S101: Based on the voltage correction event triggered when the cell voltage reaches the preset correction condition, obtain the current state-of-charge (SOC) reference value and the preset correction range near the correction point.

[0018] During the operation of the energy storage system, the battery management system collects the terminal voltage of each cell in real time and compares the collected cell voltage with pre-configured correction conditions. When the cell voltage meets the preset correction conditions, a voltage correction event is triggered. This voltage correction event is considered a reliable anchor point in the SOC estimation process. That is, at the moment of triggering this event, the battery's true SOC can be determined as a known accurate value based on the cell voltage characteristics, and this known accurate value serves as the SOC benchmark value. At the same time, a preset correction interval is defined near this correction trigger point. SOC estimates within this preset correction interval are considered accurate and are no longer included in the statistics and calculation of zero drift error.

[0019] Reference Figure 3 As shown, the steps described above for obtaining the SOC reference value and the preset correction range based on the voltage correction event specifically include the following three scenarios.

[0020] The first scenario is full charge correction. When the cell voltage rises to the full charge voltage threshold, the battery is determined to be in a fully charged state, thus generating a full charge correction trigger signal. Based on this full charge correction trigger signal, the current SOC is set to the full charge corresponding value, which serves as the SOC reference value for this correction. Simultaneously, a high SOC correction range is defined near the full charge correction point, and one end of this high SOC correction range extends a preset width in the direction of SOC reduction from the full charge correction point. The SOC within this high SOC correction range is considered accurate.

[0021] The second scenario is full-discharge correction. When the cell voltage drops to the discharge voltage threshold, the battery is determined to be in a discharged state, thus generating a full-discharge correction trigger signal. Based on this full-discharge correction trigger signal, the current SOC is set as the discharge-corresponding value, which serves as the SOC reference value for this correction. Simultaneously, a low SOC correction range is defined near the full-discharge correction point, close to the discharged state. One end of this low SOC correction range extends a preset width in the direction of increasing SOC, with the full-discharge correction point as the reference. The SOC within this low SOC correction range is considered accurate.

[0022] The third scenario is dynamic voltage correction. When the cell voltage reaches the preset voltage point at the end of charging and discharging, a dynamic voltage correction event is triggered, thus obtaining a dynamic voltage correction trigger signal. Based on this dynamic voltage correction trigger signal, the preset SOC value corresponding to the preset voltage point is used as the SOC reference value for this correction. This dynamic voltage correction is suitable for the end region where the voltage characteristics are more obvious during charging and discharging, and can provide an additional correction anchor point between full charge and full discharge.

[0023] After obtaining the high SOC correction range and the low SOC correction range, the battery management system independently performs statistical analysis on the data within each range. Specifically, based on the high SOC correction range, the SOC deviation value and effective current time statistics between correction events triggered within that range are independently statistically analyzed to obtain the high range statistical results. Similarly, based on the low SOC correction range, the SOC deviation value and effective current time statistics between correction events triggered within that range are independently statistically analyzed to obtain the low range statistical results. It should be noted that after triggering full charge or full discharge correction, the SOC within the preset correction range closest to the correction point is considered accurate. Therefore, statistical analysis only begins when a correction is triggered again within that preset correction range, and the corresponding range statistical results are obtained based on the two correction events within the same preset correction range. The high range statistical results and the low range statistical results are independent and do not interfere with each other, thus avoiding zero drift identification errors caused by differences in battery characteristics within different SOC ranges.

[0024] Step S102: Based on the SOC integral value before the next correction obtained by ampere-hour integration and the SOC reference value, and under the condition that no other correction is triggered outside the preset correction interval between two adjacent corrections, the SOC deviation value is obtained.

[0025] After a voltage correction event is triggered, the battery management system resets the State of Charge (SOC) estimate to the baseline SOC value for that correction and then performs time integration based on the corrected ampere-hour integrated current value to maintain continuous SOC estimation. When the next voltage correction event is triggered, the SOC integral value accumulated by ampere-hour integration before the current correction is the SOC integral value before the next correction. Comparing this SOC integral value with the baseline SOC value for the next correction, the difference between the two values ​​reflects the error accumulated by ampere-hour integration between the two corrections.

[0026] To ensure that this difference can be accurately attributed to the current zero-drift bias, this step sets a strict precondition: no other corrections are triggered outside the preset correction interval between two adjacent corrections. Under this condition, the SOC between two corrections is updated only by the ampere-hour integral calculation, and no other correction events interfere with the SOC. Therefore, the difference between the SOC integral value and the SOC reference value can fully reflect all the errors accumulated by the ampere-hour integral between the two corrections.

[0027] Specifically, if the cell voltage does not reach any preset correction conditions between two consecutive corrections and no other corrections are triggered outside the preset correction range, the SOC between the two corrections is determined to be updated only by ampere-hour integration. Subsequently, the SOC deviation value between the two corrections is obtained based on the difference between the unlimited SOC integral value accumulated by ampere-hour integration before the second correction and the SOC reference value after the second correction. The SOC integral value used here is the original unlimited integration result to avoid the limiting operation masking the true integration error. This second correction is considered to be caused by the deviation between the SOC accumulated by ampere-hour integration and the true SOC; therefore, the SOC deviation value reflects the accumulated integration error between the two corrections. Furthermore, the direction of the integration error between the two corrections can be determined based on the sign of the SOC deviation value: when the SOC deviation value is positive, it indicates that the SOC obtained by ampere-hour integration is higher than the true SOC; when the SOC deviation value is negative, it indicates that the SOC obtained by ampere-hour integration is lower than the true SOC.

[0028] Step S103: Based on the effective current duration during which the DC side current amplitude exceeds the preset filtering threshold between two adjacent corrections, obtain the effective current time statistics.

[0029] The battery management system receives the DC-side current collected by the power conversion system and obtains the real-time current amplitude. This real-time current amplitude is compared with a preset filtering threshold: if the real-time current amplitude is greater than the preset filtering threshold, the current segment is determined to be valid current; if the real-time current amplitude is not greater than the preset filtering threshold, the current segment is determined to be filtered current. Within the time period corresponding to the filtered current, the current amplitude is small, the relative error of current sampling is large, and there may be uncounted circulating current or self-discharge under low-current conditions. Including this time period in the statistics would interfere with the accurate identification of zero-drift error; therefore, it is excluded.

[0030] Between two consecutive corrections, the durations of all currents deemed effective are summed to obtain an effective current time statistic. This effective current time statistic excludes the duration of filtered currents, thus preventing uncounted currents from affecting zero-drift error calculations under low-current conditions. Furthermore, based on the preset correction intervals to which two consecutive corrections belong, effective current time statistics corresponding to each preset correction interval are obtained. Specifically, the effective current time statistics within the high SOC correction interval and the effective current time statistics within the low SOC correction interval are summed and stored separately to support independent interval statistics.

[0031] Step S104: Based on the SOC deviation value, the battery rated capacity, and the effective current time statistics, the theoretical current zero drift error value is obtained.

[0032] After obtaining the SOC deviation value and the effective current time statistics, the SOC deviation value is converted into the corresponding total deviation charge. Then, based on the average distribution of the total deviation charge over the effective current time, the average current deviation that causes the deviation is deduced. This average current deviation is the theoretical current zero drift error value.

[0033] Specifically, the total deviation charge is first obtained by multiplying the SOC deviation value by the battery's rated capacity. The SOC deviation value is a dimensionless proportional quantity; multiplying it by the battery's rated capacity converts it into a total deviation in terms of charge. Then, the theoretical current zero-drift error value is obtained by dividing this total deviation charge by the effective current-time statistics. In simpler terms, the theoretical current zero-drift error value equals the product of the SOC deviation value and the battery's rated capacity, divided by the effective current-time statistics. This theoretical current zero-drift error value characterizes the average current deviation that causes the SOC deviation value within the effective current-time statistics.

[0034] Based on the sign of the SOC deviation value, the sign and physical meaning of the theoretical current zero-drift error value can be determined: when the SOC deviation value is an upward correction event, that is, the SOC obtained by ampere-hour integration is higher than the true SOC, it indicates that the integrated current is relatively large compared to the actual current, and the theoretical current zero-drift error value is positive; when the SOC deviation value is a downward correction event, that is, the SOC obtained by ampere-hour integration is lower than the true SOC, it indicates that the integrated current is relatively small compared to the actual current, and the theoretical current zero-drift error value is negative. This sign relationship provides a basis for the direction of subsequent current compensation.

[0035] Step S105: Based on the theoretical current zero drift error value and the preset proportional coefficient, obtain the current zero drift correction increment for this operation.

[0036] Considering that the theoretical current zero-drift error value obtained from a single calculation may contain disturbance errors, directly using this theoretical value to fully correct the current zero-drift may cause correction oscillations or even divergence. Therefore, this step introduces a preset proportional coefficient to partially optimize the theoretical current zero-drift error value.

[0037] Specifically, the optimized ratio for this correction is obtained based on a preset proportional coefficient. This optimized ratio is configured so that each correction only optimizes a portion of the theoretical current zero-drift error value, rather than correcting the entire value. Subsequently, the current zero-drift correction increment is obtained by multiplying the theoretical current zero-drift error value by this optimized ratio. By repeatedly calculating and accumulating the current zero-drift correction increment through correction events triggered within multiple correction intervals, a correction process that gradually approximates the true zero-drift value is obtained, forming a progressive optimization. This progressive optimization process is used to avoid correction oscillations caused by single overcorrection. When the theoretical current zero-drift error value calculated in this instance contains disturbance errors, a correction result with controllable single-time deviation can be obtained, allowing the zero-drift correction value to converge smoothly over multiple corrections.

[0038] Step S106: Based on the previous current zero drift correction value and the current current zero drift correction increment, limit the amplitude within the preset correction range to obtain the updated current zero drift correction value.

[0039] After obtaining the increment of the current zero drift correction, it is added to the previous current zero drift correction value to obtain the preliminary correction value. In simpler terms, the preliminary correction value equals the sum of the previous current zero drift correction value and the current current zero drift correction increment.

[0040] Subsequently, the initial correction value is compared with the upper and lower limits of a preset correction range. When the initial correction value exceeds the upper limit of the preset correction range, the upper limit is taken as the updated current zero-drift correction value; when the initial correction value is lower than the lower limit of the preset correction range, the lower limit is taken as the updated current zero-drift correction value; when the initial correction value is within the preset correction range, the initial correction value is taken as the updated current zero-drift correction value. Through the above limiting operation, a continuously updated and limited zero-drift bias is obtained between two corrections to prevent abnormal corrections caused by correction value divergence. The preset correction range is determined based on the physical upper limit of zero-drift of the current sampling circuit, ensuring that the corrected current zero-drift correction value is always within a reasonable physical range.

[0041] Step S107: Based on the original sampled current and the updated current zero drift correction value, obtain the corrected ampere-hour integrated current value.

[0042] After obtaining the updated current zero-drift correction value, it is applied to compensate the original sampled current. Specifically, the original sampled current is compensated accordingly based on the direction of the updated current zero-drift correction value: when the current zero-drift correction value is positive, it indicates that the original sampled current is relatively large compared to the true current, and the current zero-drift correction value is subtracted from the original sampled current; when the current zero-drift correction value is negative, it indicates that the original sampled current is relatively small compared to the true current, and the absolute value of the current zero-drift correction value is added to the original sampled current. Through the above compensation, the corrected ampere-hour integral current value with reduced integral deviation is obtained.

[0043] After obtaining the corrected ampere-hour integrated current value, time integration is performed based on this corrected ampere-hour integrated current value to obtain an updated SOC estimate, which is maintained until the next voltage correction trigger. This method attributes the SOC deviation to the current zero-drift bias factor for correction and excludes other influencing factors, including unstatistically uncounted small circulating currents, self-discharge statistical errors, and coulombic efficiency decay caused by cell aging, so that the corrected ampere-hour integrated current value only reflects the zero-drift bias compensation. The above-mentioned method of excluding other influencing factors is achieved through the exclusion of the filter current period in step S103 and the premise constraint in step S102 that there are no other correction events between two adjacent corrections, thereby ensuring the purity of the zero-drift error identification.

[0044] Thus, the adaptive current error calculation method described in this embodiment completes a full correction cycle. During the continuous operation of the energy storage system, steps S101 to S107 are executed cyclically with each voltage correction event. The current zero drift correction value gradually approaches the true zero drift value through multiple corrections, thereby continuously improving the accuracy and stability of SOC estimation.

[0045] Example 2 This embodiment provides a current error adaptive calculation system, which implements the current error adaptive calculation method described in Embodiment 1. (Refer to...) Figure 2 As shown, the system includes a voltage correction module, a deviation calculation module, a time statistics module, an error estimation module, an incremental calculation module, a correction and update module, and a current output module.

[0046] The voltage correction module is used to obtain the current, considered accurate SOC reference value and the preset correction range near the correction point based on the voltage correction event triggered when the cell voltage reaches a preset correction condition. This voltage correction module further distinguishes between three scenarios: full charge correction, full discharge correction, and dynamic voltage correction, corresponding to events where the cell voltage reaches the full charge voltage threshold, the discharge voltage threshold, and the preset voltage point at the end of charge / discharge, respectively. Based on these, it obtains a high SOC correction range, a low SOC correction range, and the corresponding SOC reference value. The voltage correction module also performs independent statistical analysis on the data within the high and low SOC correction ranges, obtaining statistical results for the high and low ranges.

[0047] The deviation calculation module is used to obtain the SOC deviation value based on the SOC integral value before the next correction obtained by ampere-hour integration and the SOC reference value, provided that no other corrections are triggered outside the preset correction interval between two adjacent corrections. This deviation calculation module uses the difference between the unlimited SOC integral value obtained by ampere-hour integration before the second correction and the SOC reference value after the second correction as the SOC deviation value, and determines the direction of the integration error based on the sign of the SOC deviation value.

[0048] The time statistics module is used to obtain effective current time statistics based on the duration of effective current where the DC-side current amplitude exceeds a preset filtering threshold between two adjacent corrections. This module classifies current segments with real-time current amplitudes greater than the preset filtering threshold as effective currents and current segments with amplitudes not exceeding the preset filtering threshold as filtered currents. It also accumulates the durations of effective currents while excluding the durations of filtered currents. Furthermore, the time statistics module obtains effective current time statistics corresponding to each preset correction interval to which two adjacent corrections belong.

[0049] The error estimation module is used to obtain the theoretical current zero-drift error value based on the SOC deviation value, battery rated capacity, and effective current time statistics. This module first calculates the total deviation charge by multiplying the SOC deviation value by the battery rated capacity, then calculates the quotient of this total deviation charge by the effective current time statistics to obtain the theoretical current zero-drift error value, and determines the sign of the theoretical current zero-drift error value based on the sign of the SOC deviation value.

[0050] The incremental calculation module is used to obtain the current zero-drift correction increment based on the theoretical current zero-drift error value and a preset proportional coefficient. This incremental calculation module uses the preset proportional coefficient as the optimization ratio, and only takes a portion of the theoretical current zero-drift error value as the correction increment, forming a progressive optimization process through multiple correction events.

[0051] The correction and update module is used to limit the current zero drift correction value within a preset correction range based on the previous current zero drift correction value and the current current zero drift correction increment, thereby obtaining an updated current zero drift correction value. This module uses the sum of the previous current zero drift correction value and the current current zero drift correction increment as a preliminary correction value, and compares this preliminary correction value with the upper and lower limits of the preset correction range. If it exceeds the upper limit, the upper limit is used; if it falls below the lower limit, the lower limit is used; and if it is within the range, the preliminary correction value itself is used, thus obtaining a limited updated current zero drift correction value.

[0052] The current output module is used to obtain the corrected ampere-hour integrated current value based on the original sampled current and the updated current zero-drift correction value. This current output module compensates the original sampled current accordingly based on the direction of the updated current zero-drift correction value, obtaining a corrected ampere-hour integrated current value with reduced integration deviation. This corrected ampere-hour integrated current value is then output to the SOC estimation stage to maintain continuous SOC estimation.

[0053] The above modules work together. The output of the voltage correction module serves as the input to the deviation calculation module and the time statistics module. The outputs of the deviation calculation module and the time statistics module together serve as the input to the error estimation module. The output of the error estimation module serves as the input to the incremental calculation module. The output of the incremental calculation module serves as the input to the correction and update module. The output of the correction and update module serves as the input to the current output module, thus forming a complete current zero-drift adaptive correction closed loop.

[0054] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

[0055] The above description is the preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principles described in this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. An adaptive calculation method for current error, characterized in that, A battery management system applied to an energy storage system, the method comprising the following steps: Based on the voltage correction event triggered when the cell voltage reaches the preset correction condition, the current state-of-charge (SOC) reference value and the preset correction range near the correction point are obtained. Based on the SOC integral value before the next correction obtained by ampere-hour integration and the SOC benchmark value, the SOC deviation value is obtained under the condition that no other correction is triggered outside the preset correction interval between two adjacent corrections. The effective current time statistics are obtained based on the effective current duration between two adjacent corrections where the DC side current amplitude exceeds the preset filtering threshold. Based on the SOC deviation value, the battery rated capacity, and the effective current time statistics, the theoretical current zero drift error value is obtained. Based on the theoretical current zero drift error value and the preset proportional coefficient, the current zero drift correction increment is obtained. Based on the previous current zero drift correction value and the current current zero drift correction increment, the amplitude is limited within the preset correction range to obtain the updated current zero drift correction value. Based on the original sampled current and the updated current zero-drift correction value, the corrected ampere-hour integral current value is obtained.

2. The adaptive current error calculation method according to claim 1, characterized in that, The step of obtaining the SOC reference value and the preset correction range based on the voltage correction event specifically includes: Based on the event that the cell voltage reaches the full charge voltage threshold, a full charge correction trigger signal is obtained, and based on the full charge correction trigger signal, a SOC reference value corresponding to the full charge value and a high SOC correction range close to the full charge state are obtained. Based on the event that the cell voltage reaches the discharge voltage threshold, a full discharge correction trigger signal is obtained, and based on the full discharge correction trigger signal, a SOC reference value corresponding to the discharge value and a low SOC correction range close to the discharge state are obtained. Based on the event that the cell voltage reaches the preset voltage point at the end of charging and discharging, a dynamic voltage correction trigger signal is obtained, and based on the dynamic voltage correction trigger signal, a SOC reference value as a preset value is obtained.

3. The adaptive current error calculation method according to claim 2, characterized in that, After obtaining the high SOC correction range and the low SOC correction range, the process further includes: Based on the high SOC correction interval, the SOC deviation value and effective current time statistics within the high SOC correction interval are independently statistically analyzed to obtain the high interval statistical results. Based on the low SOC correction interval, the SOC deviation value and effective current time statistics within the low SOC correction interval are independently statistically analyzed to obtain the low interval statistical results. Specifically, after triggering a full charge correction or a full discharge correction, the SOC within the preset correction interval close to the correction point is considered accurate. Statistics are only started when a correction is triggered again within the preset correction interval, and the corresponding interval statistics are obtained based on the two correction events within the same preset correction interval.

4. The adaptive current error calculation method according to claim 3, characterized in that, The step of obtaining the SOC deviation value specifically includes: If the cell voltage does not reach any preset correction condition between two consecutive corrections and no other corrections are triggered outside the preset correction range, the SOC between the two corrections is determined to be updated only by ampere-hour integration. The SOC deviation between the two corrections is obtained by comparing the unlimited SOC integral value accumulated from the ampere-hour integral before the second correction with the SOC reference value after the second correction. The second correction is considered to be caused by the deviation between the SOC obtained by the ampere-hour integration and the true SOC, and the SOC deviation value reflects the cumulative integration error between the two corrections; The direction of the integral error between the two corrections is obtained based on the sign of the SOC deviation value.

5. The adaptive current error calculation method according to claim 4, characterized in that, The step of obtaining the effective current time statistics specifically includes: The real-time current amplitude is obtained based on the DC-side current collected by the power conversion system received by the battery management system. Based on the event that the real-time current amplitude is greater than the preset filtering threshold, the current segment is determined to be an effective current, and based on the event that the real-time current amplitude is not greater than the preset filtering threshold, the current segment is determined to be a filtered current. The effective current time statistics are obtained by summing the duration of the effective current between two consecutive corrections. The effective current time statistics exclude the duration of the filtered current to avoid the influence of unstated current under low current conditions on the zero drift error calculation. Based on the preset correction interval to which the two adjacent corrections belong, the effective current time statistics corresponding to each preset correction interval are obtained.

6. The adaptive current error calculation method according to claim 5, characterized in that, The step of obtaining the theoretical current zero-drift error value specifically includes: The total deviation charge is obtained by multiplying the SOC deviation value by the battery's rated capacity. The theoretical current zero drift error value is obtained by dividing the total deviation charge by the effective current time statistics. The theoretical current zero drift error value represents the average current deviation that causes the SOC deviation value within the effective current time statistics. Based on the event of upward correction of the SOC deviation value, the integral current is larger than the actual current and the theoretical current zero drift error value is positive; based on the event of downward correction of the SOC deviation value, the integral current is smaller than the actual current and the theoretical current zero drift error value is negative.

7. The adaptive current error calculation method according to claim 6, characterized in that, The step of obtaining the current zero-drift correction increment based on the theoretical current zero-drift error value and a preset proportional coefficient specifically includes: The optimized ratio for this correction is obtained based on the preset proportional coefficient. The optimized ratio is configured such that each correction only optimizes a portion of the theoretical current zero drift error value. The current zero-drift correction increment is obtained by multiplying the theoretical current zero-drift error value by the optimization ratio. Based on the correction events triggered in multiple correction intervals, the current zero drift correction increment is obtained to gradually approach the true zero drift value, forming a progressive optimization process. The progressive optimization process is used to avoid correction oscillations caused by single overcorrection. When the theoretical current zero drift error value calculated in this case contains disturbance error, a correction result with controllable single deviation is obtained.

8. The adaptive current error calculation method according to claim 7, characterized in that, The step of obtaining the updated current zero-drift correction value specifically includes: The preliminary correction value is obtained by summing the previous current zero drift correction value and the current current zero drift correction increment. Based on the comparison between the preliminary correction value and the upper and lower limits of the preset correction range, the updated current zero drift correction value is obtained. Wherein, when the initial correction value exceeds the upper limit or falls below the lower limit, the boundary value of the preset correction range is taken as the updated current zero drift correction value; when the initial correction value is within the preset correction range, the initial correction value is taken as the updated current zero drift correction value. Based on the updated current zero-drift correction value, a constrained zero-drift bias is obtained that is continuously updated between two corrections to prevent abnormal corrections caused by the divergence of the correction value.

9. The adaptive current error calculation method according to claim 8, characterized in that, After obtaining the corrected ampere-hour integrated current value, the method further includes: The updated SOC estimate is obtained by integrating the corrected ampere-hour integrated current value over time. Based on the updated SOC estimate, the SOC estimate is maintained until the next voltage correction trigger. Based on the direction of the updated current zero drift correction value, the original sampled current is compensated accordingly to obtain the corrected ampere-hour integrated current value with reduced integration deviation. The method corrects the SOC deviation value by attributing it to the current zero drift bias factor and excludes other influencing factors, including unstatistically circulated currents, self-consumption statistical errors, and coulombic efficiency decay caused by cell aging, so that the corrected ampere-hour integral current value only reflects the compensation for zero drift bias.

10. A current error adaptive calculation system, wherein the system implements the method as described in any one of claims 1 to 9, characterized in that, include: The voltage correction module is used to obtain the current accurate SOC reference value and the preset correction range near the correction point based on the voltage correction event triggered when the cell voltage reaches the preset correction condition. The deviation calculation module is used to obtain the SOC deviation value based on the SOC integral value before the next correction obtained by ampere-hour integration and the SOC reference value, provided that no other correction is triggered outside the preset correction interval between two adjacent corrections. The time statistics module is used to obtain the effective current time statistics value based on the effective current duration between two adjacent corrections where the DC side current amplitude exceeds the preset filtering threshold. The error estimation module is used to obtain the theoretical current zero drift error value based on the SOC deviation value, the battery rated capacity, and the effective current time statistics. The incremental calculation module is used to obtain the current zero drift correction increment based on the theoretical current zero drift error value and the preset proportional coefficient. The correction and update module is used to limit the current zero drift correction value within a preset correction range based on the previous current zero drift correction value and the current current zero drift correction increment, and obtain the updated current zero drift correction value. The current output module is used to obtain the corrected ampere-hour integrated current value based on the original sampled current and the updated current zero drift correction value.

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