# US 10,871,521 B2 · Method and apparatus for correcting SOC, battery management system and storage medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,871,521 B2 - Document ID: US10871521B2 - Status: Granted - Kind: B2 - Application number: 16/856,638 - Filed: 2020-04-23 - Published: 2020-11-26 - Granted: 2020-12-22 - Earliest claimed: 2019-05-24 - Assignees: Contemporary Amperex Technology Co., Limited - Applicants: Contemporary Amperex Technology Co., Limited - Inventors: Jian Ruan; Shichao Li; Mingshu Du; Shenzhi Tang; Yanhua Lu; Wei Zhang - Web page: https://patentgrep.com/patent/US10871521B2 ## CPC - G01R 31/367: Software therefor, e.g. for battery testing using modelling or look-up tables - G01R 31/3648: {comprising digital calculation means, e.g. for performing an algorithm} - G01R 31/374: with means for correcting the measurement for temperature or ageing - G01R 31/3835: involving only voltage measurements - G01R 31/3842: combining voltage and current measurements - G01R 31/388: involving voltage measurements - G01R 31/392: Determining battery ageing or deterioration, e.g. state of health - G01R 31/396: Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery - H02J 7/82: Control of state of charge [SOC] - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A method and apparatus for correcting a state of charge (SOC) is provided. The method includes: acquiring state data of a battery cell in a case where the battery cell meets a preset standing condition; determining, when a length of voltage data in the state data is greater than a first preset length and less than a second preset length, and a change value of the voltage data in the state data is greater than a preset change threshold, a first set of pending parameters of a predetermined near-steady-state battery model according to the state data; predicting, according to the first set of pending parameters, a second set of pending parameters of the predetermined near-steady-state battery model; calculating an estimated steady-state OCV value according to the second set of pending parameters; and determining a SOC correction value corresponding to the estimated steady-state OCV value to correct current SOC. ## Claims ### Claim 1 A method for correcting a State of Charge (SOC), comprising: acquiring state data of a battery cell in a case where the battery cell meets a preset standing condition; determining a first set of pending parameters of a predetermined near-steady-state battery model according to the state data of the battery cell, when a length of voltage data in the state data of the battery cell is greater than a first preset length and less than a second preset length, and a change value of the voltage data in the state data of the battery cell is greater than a preset change threshold; predicting a second set of pending parameters of the predetermined near-steady-state battery model according to the first set of pending parameters; calculating an estimated steady-state Open Circuit Voltage (OCV) value according to the second set of pending parameters; and determining a SOC correction value corresponding to the estimated steady-state OCV value by using a preset correspondence between steady-state OCVs and SOCs to correct a current SOC. ### Claim 2 (depends on 1) The method according to claim 1, further comprising: determining the first set of pending parameters of the predetermined near-steady-state battery model according to the state data of the battery cell, when the length of voltage data in the state data of the battery cell is greater than the second preset length and the change value of the voltage data in the state data of the battery cell is greater than the preset change threshold; determining the estimated steady-state OCV value according to the first set of pending parameters; and determining the SOC correction value corresponding to the estimated steady-state OCV value by using the preset correspondence between steady-state OCVs and SOCs to correct the current SOC. ### Claim 3 (depends on 1) The method according to claim 1, further comprising: determining an estimated unsteady-state OCV value according to the state data of the battery cell, when the length of voltage data in the state data of the battery cell is greater than the first preset length and less than the second preset length and the change value of the voltage data in the state data of the battery cell is smaller than the preset change threshold; or determining an estimated unsteady-state OCV value according to the state data of the battery cell, when the length of voltage data in the state data of the battery cell is greater than the second preset length and the change value of the voltage data in the state data of the battery cell is smaller than the preset change threshold; and determining a SOC correction value corresponding to the estimated unsteady-state OCV value by using a preset correspondence between unsteady-state OCVs and SOCs to correct the current SOC. ### Claim 4 (depends on 1) The method according to claim 1, wherein the predicting the second set of pending parameters of the predetermined near-steady-state battery model according to the first set of pending parameters comprises: predicting the second set of pending parameters of the predetermined near-steady-state battery model according to the first set of pending parameters as well as a preset correspondence between the first set of pending parameters and the second set of pending parameters for the length of the voltage data. ### Claim 5 (depends on 1) The method according to claim 1, wherein the calculating the estimated steady-state OCV value according to the second set of pending parameters comprises: determining a steady-state time period threshold corresponding to the state data of the battery cell; and processing the steady-state time period threshold by using the near-steady-state battery model determined by the second set of pending parameters so as to obtain the estimated steady-state OCV value. ### Claim 6 (depends on 1) The method according to claim 1, wherein the determining the SOC correction value corresponding to the estimated steady-state OCV value by using the preset correspondence between steady-state OCVs and SOCs to correct the current SOC comprises: determining whether the estimated steady-state OCV value exceeds a preset estimated OCV range; and determining, when the estimated steady-state OCV value does not exceed the preset estimated OCV range, the SOC correction value corresponding to the estimated steady-state OCV value by using the preset correspondence between steady-state OCVs and SOCs to correct the current SOC. ### Claim 7 (depends on 3) The method according to claim 3, further comprising: determining a voltage rebound direction during a standing time period of the battery cell; correcting, when the voltage rebound direction indicates a voltage increase and the SOC correction value corresponding to the estimated unsteady-state OCV is greater than the current SOC, the current SOC by using the SOC correction value corresponding to the estimated unsteady-state OCV value. ### Claim 8 (depends on 7) The method according to claim 7, further comprising: correcting, when the voltage rebound direction indicates a voltage decrease and the SOC correction value corresponding to the estimated unsteady-state OCV is smaller than the current SOC, the current SOC by using the SOC correction value corresponding to the estimated unsteady-state OCV value. ### Claim 9 (depends on 1) The method according to claim 1, wherein the method further comprising: performing a fitting process according to the voltage data in the state data of the battery cell to obtain m sub-near-steady-state battery models, m fitted curves and corresponding fitted difference values; and sorting the m sub-near-steady-state battery models according to the fitted difference values, and setting a sum of first n sub-near-steady-state battery models with minimal fitted difference values as the preset near-steady-state battery model; wherein the state data of the battery cell comprises: State of Health (SOH), voltage, current, and temperature. ### Claim 10 (depends on 1) The method according to claim 1, wherein the preset standing condition is that a current of the battery cell is less than a preset current threshold. ### Claim 11 A storage medium having a program stored thereon, wherein the program is executed by a processor to implement: acquiring state data of a battery cell in a case where the battery cell meets a preset standing condition; determining a first set of pending parameters of a predetermined near-steady-state battery model according to the state data of the battery cell when a length of voltage data in the state data of the battery cell is greater than a first preset length and less than a second preset length and a change value of the voltage data in the state data of the battery cell is greater than a preset change threshold; predicting a second set of pending parameters of the predetermined near-steady-state battery model according to the first set of pending parameters; and calculating an estimated steady-state Open Circuit Voltage (OCV) value according to the second set of pending parameters; and determining a State of Charge (SOC) correction value corresponding to the estimated steady-state OCV value by using a preset correspondence between steady-state OCVs and SOCs to correct a current SOC. ### Claim 12 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to further implement: determining the first set of pending parameters of the predetermined near-steady-state battery model according to the state data of the battery cell, when the length of voltage data in the state data of the battery cell is greater than the second preset length and the change value of the voltage data in the state data of the battery cell is greater than the preset change threshold; and determining the estimated steady-state OCV value according to the first set of pending parameters; and determining the SOC correction value corresponding to the estimated steady-state OCV value by using the preset correspondence between steady-state OCVs and SOCs to correct the current SOC. ### Claim 13 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to further implement: determining an estimated unsteady-state OCV value according to the state data of the battery cell, when the length of voltage data in the state data of the battery cell is greater than the first preset length and less than the second preset length and the change value of the voltage data in the state data of the battery cell is smaller than the preset change threshold; or determining an estimated unsteady-state OCV value according to the state data of the battery cell, when the length of voltage data in the state data of the battery cell is greater than the second preset length and the change value of the voltage data in the state data of the battery cell is smaller than the preset change threshold; and determining a SOC correction value corresponding to the estimated unsteady-state OCV value by using a preset correspondence between unsteady-state OCVs and SOCs to correct the current SOC. ### Claim 14 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to specifically implement: predicting the second set of pending parameters of the predetermined near-steady-state battery model according to the first set of pending parameters as well as a preset correspondence between the first set of pending parameters and the second set of pending parameters for the length of the voltage data. ### Claim 15 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to specifically implement: determining a steady-state time period threshold corresponding to the state data of the battery cell; and processing the steady-state time period threshold by using the near-steady-state battery model determined by the second set of pending parameters so as to obtain the estimated steady-state OCV value. ### Claim 16 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to specifically implement: determining whether the estimated steady-state OCV value exceeds a preset estimated OCV range; and determining, when the estimated steady-state OCV value does not exceed the preset estimated OCV range, the SOC correction value corresponding to the estimated steady-state OCV value by using the preset correspondence between steady-state OCVs and SOCs to correct the current SOC. ### Claim 17 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to further implement: determining a voltage rebound direction during a standing time period of the battery cell; correcting, when the voltage rebound direction indicates a voltage increase and the SOC correction value corresponding to the estimated unsteady-state OCV is greater than the current SOC, the current SOC by using the SOC correction value corresponding to the estimated unsteady-state OCV value. ### Claim 18 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to further implement: correcting, when the voltage rebound direction indicates a voltage decrease and the SOC correction value corresponding to the estimated unsteady-state OCV is smaller than the current SOC, the current SOC by using the SOC correction value corresponding to the estimated unsteady-state OCV value. ### Claim 19 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to further implement: performing a fitting process according to the voltage data in the state data of the battery cell to obtain m sub-near-steady-state battery models, m fitted curves and corresponding fitted difference values; and sorting the m sub-near-steady-state battery models according to the fitted difference values, and setting a sum of first n sub-near-steady-state battery models with minimal fitted difference values as the preset near-steady-state battery model; wherein the state data of the battery cell comprises: State of Health (SOH), voltage, current, and temperature. ### Claim 20 (depends on 11) The storage medium according to claim 11, wherein the program is executed by the processor to specifically implement: acquiring state data of a battery cell in a case where the battery cell meets a preset standing condition, wherein the preset standing condition is that a current of the battery cell is less than a preset current threshold.