Method for estimating battery cell capacity, battery management system, vehicle, and computer program product

Abstract

The present application relates a method for estimating the capacity of a battery cell, including: charging a battery pack including a plurality of battery cells until the charging of the battery pack is ended (S1); discharging the battery cells of the battery pack until an estimated state of charge SOCp of a first battery cell of the battery pack decreases to a preset state of charge threshold, wherein the estimated state of charge of the first battery cell is determined on the basis of an estimated battery capacity state of health SOHCp of the first battery cell (S2); calculating a battery capacity state of health SOHCc of the first battery cell on the basis of a discharge amount and an estimated state of charge variation of the first battery cell during the discharging process, and correcting the estimated battery capacity state of health of the first battery cell by means of the calculated battery capacity state of health (S3); and repeating steps S1 to S3 until a deviation value between the calculated battery capacity state of health and the estimated battery capacity state of health of the first battery cell is less than a preset deviation threshold (S4).

Description

[0001] METHOD FOR ESTIMATING BATTERY CELL CAPACITY, BATTERY MANAGEMENT SYSTEM, VEHICLE, AND COMPUTER PROGRAM PRODUCT

[0002] TECHNICAL FIELD

[0003] The present application relates to the field of batteries, and relates in particular to a method for estimating the capacity of a battery cell, a battery management system, a vehicle including the battery management system, and a computer program product which is used to at least assist in implementing steps of the method according to the present application.

[0004] BACKGROUND

[0005] A battery pack is composed of a certain number of battery cells connected in series and / or in parallel, and individual battery cells may experience varying degrees of capacity degradation during the use of the battery pack. In particular, the performance of a battery cell will decrease sharply after its capacity decreases by more than 80%, resulting in the failure of the battery cell, and thereby causing the entire battery pack to be unable to operate normally. In addition, if the battery management system fails to promptly obtain the real-time capacity of the battery cells, the calculation of the state of charge of the battery cells by the battery management system and various control processes based on the state of charge of the battery cells will also be seriously affected, especially causing great errors.

[0006] Therefore, how to regularly, efficiently, and accurately estimate battery capacity has become a technical problem to be solved.

[0007] SUMMARY

[0008] An objective of the present application is to provide a method for estimating the capacity of a battery cell, a battery management system, a vehicle comprising the battery management system, and a computer program product, so as to at least partially solve the problem in the prior art.

[0009] According to a first aspect of the present application, a method for estimating the capacity of a battery cell is provided, the method comprising: step SI: charging a battery pack comprising a plurality of battery cells until the charging of the battery pack is ended; step S2: discharging the battery cells of the battery pack until an estimated state of charge SOCPof a first battery cell of the battery pack decreases to a preset state of charge threshold SOCt, wherein the estimated state of charge SOCPof the first battery cell is determined on the basis of an estimated battery capacity state of health SOHCPof the first battery cell; step S3: calculating a battery capacity state of health SOHCc of the first battery cell on the basis of a discharge amount Q and an estimated state of charge variation ASOCPof the first battery cell during the discharging process, and correcting the estimated battery capacity state of health SOHCPof the first battery cell by means of the calculated battery capacity state of health SOHCc ; and step S4: repeating steps SI to S3 until a deviation value between the calculated battery capacity state of health SOHCc and the estimated battery capacity state of health SOHCPof the first battery cell is less than a preset deviation threshold.

[0010] The core concept of the present application is as follows: the capacity of the battery cell is efficiently and accurately calculated by means of a regression algorithm during the charging and discharging cycle of the battery pack, and the battery capacity state of health stored in the battery management system is corrected until the calculated battery capacity state of health converges, thereby eliminating the influence and error caused by the capacity of a battery cell that has not been updated for a long time on the calculation of the state of charge of the battery cell and various control processes based on the state of charge of the battery cell without adding hardware testing equipment.

[0011] According to another embodiment of the present application, the estimated battery capacity state of health SOHCPof the first battery cell is corrected by replacing the estimated battery capacity state of health SOHCPof the first battery cell with an average value of the calculated battery capacity state of health SOHCc and the estimated battery capacity state of health SOHCPof the first battery cell.

[0012] According to another embodiment of the present application, during the charging process of the battery pack, individual battery cells of the battery pack are balanced. According to another embodiment of the present application, the preset state of charge threshold SOCt may be determined on the basis of an operating point of a vehicle power system and / or a relaxation voltage capacity of the first battery cell, wherein the preset state of charge threshold is greater than a state of charge value SOCL at which a low-voltage plateau inflection point appears in a voltage-capacity characteristic curve of the first battery cell and less than a state of charge value SOCH at which a high-voltage plateau inflection point appears.

[0013] According to another embodiment of the present application, an open-circuit voltage of the first battery cell may be measured when the battery cells of the battery pack start discharging, and the estimated state of charge SOCPof the first battery cell at the beginning of discharging is determined by means of an open-circuit voltage method on the basis of a voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of the first battery cell.

[0014] According to another embodiment of the present application, during the discharging process of the battery pack, the open-circuit voltage of the first battery cell may be acquired, the estimated state of charge of the first battery cell is determined by means of the open-circuit voltage method on the basis of the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of the first battery cell, and the battery cells of the battery pack are controlled to stop discharging when the estimated state of charge reaches the preset state of charge threshold SOCt.

[0015] According to another embodiment of the present application, on the basis of a change process of a discharge current of the first battery cell over time, the discharge amount Q of the first battery cell during the discharging process may be calculated by means of, for example, an ampere- hour integration method.

[0016] According to another embodiment of the present application, when the first battery cell in the battery pack satisfies a predetermined capacity estimation triggering condition, execution of steps SI to S 4 may be triggered to estimate the battery capacity state of health of the first battery cell, the capacity estimation triggering condition being related to a time interval for executing capacity estimation. According to another embodiment of the present application, when one or more battery cells in the battery pack are fully charged, or in response to receiving a control instruction to stop charging, the battery pack is controlled to end charging.

[0017] According to a second aspect of the present application, a battery management system is provided, wherein the battery management system comprises the following components: at least one processor; and a memory communicatively connected to the at least one processor, wherein instructions processable by the at least one processor are stored on the memory, and the instructions, when processed by the at least one processor, implement the method according to the present application.

[0018] According to a third aspect of the present application, a vehicle is provided, wherein the vehicle comprises the battery management system according to the present application.

[0019] According to a fourth aspect of the present application, a computer program product is provided, such as a computer-readable program carrier, comprising or storing computer program instructions, wherein the computer program instructions, when executed by a processor, at least assist in implementing steps of the method according to the present application.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The principles, features, and advantages of the present application can be better understood from the following further detailed description of the present application with reference to the accompanying drawings. The accompanying drawings show:

[0022] FIG. 1 shows a workflow diagram of a method for estimating the capacity of a battery cell according to an exemplary embodiment of the present application;

[0023] FIG. 2 shows an exemplary voltage-state of charge characteristic curve diagram of a battery cell according the present application; and

[0024] FIG. 3 shows a block diagram of a battery management system according to an exemplary embodiment of the present application.

[0025] DETAILED DESCRIPTION In order to make the technical problems to be solved by the present application, the technical solutions, and the beneficial technical effects clearer, the present application will be described below in further detail with reference to the accompanying drawings and a plurality of exemplary embodiments. It should be understood that the specific embodiments described herein are merely used to explain the present application, but are not used to limit the scope of protection of the present application.

[0026] FIG. 1 shows a workflow diagram of a method for estimating the capacity of a battery cell according to an exemplary embodiment of the present application. The following exemplary embodiments describe in further detail the method according to the present application.

[0027] The method may include steps SI to S4. In the present embodiment of the present application, a battery pack includes a plurality of battery cells, and when a certain battery cell in the battery pack, which is assumed to be a first battery cell here, satisfies a predetermined capacity estimation triggering condition, the execution of steps SI to S4 may be triggered to estimate a battery capacity state of health of the first battery cell. The capacity estimation triggering condition is related to a time interval for executing capacity estimation, and considering that the capacity of the battery cell may decrease at a degradation rate of, for example, about 2% per year during actual use, execution of steps SI to S4 may be triggered when the capacity of the first battery cell has not been updated for a certain time interval (e.g., one year).

[0028] In step SI, the battery pack including the plurality of battery cells is charged until the charging of the battery pack is ended. Here, when one or more battery cells in the battery pack are fully charged, the charging of all battery cells of the battery pack is ended. Optionally, in response to receiving a control instruction to stop charging which is issued by a user or a battery management system 1, all the battery cells of the battery pack may be controlled to end charging.

[0029] It should be noted that, at the end of charging, the first battery cell that has experienced capacity degradation is not actually fully charged. Assuming that the battery management system 1 has never updated the battery capacity state of health SOHCp since the beginning of the life of the first battery cell, then the estimated battery capacity state of health SOHCp of the first battery cell stored in the battery management system 1 would be 100%, and the estimated state of charge SOCp of the first battery cell at the end of charging may be determined to be 100% according to the estimated battery capacity state of health SOHCp of the first battery cell stored in the battery management system 1.

[0030] In step S2, the battery cells of the battery pack are discharged until the estimated state of charge SOCPof the first battery cell of the battery pack decreases to a preset state of charge threshold SOCt. The battery management system 1 may determine the estimated state of charge SOCp of the first battery cell on the basis of the stored estimated battery capacity state of health SOHCp of the first battery cell, wherein the battery capacity state of health SOHC is the ratio of the current capacity of the battery pack to the nominal capacity of the battery pack, which can characterize the degree of aging of the battery. As can be understood, when the battery management system 1 has not updated the stored estimated battery capacity state of health SOHCp of the first battery cell for a long time, due to the degradation of the battery capacity, the estimated battery capacity state of health SOHCp of the first battery cell may have a large deviation from the actual battery capacity state of health SOHC, which in turn leads to, for example, a large deviation between the estimated state of charge SOCp of the first battery cell determined by means of an open-circuit voltage method and an actual state of charge SOC.

[0031] In an exemplary voltage-state of charge characteristic curve diagram of a battery cell according to the present application, as shown in FIG. 2, the solid curve represents a voltage-state of charge characteristic curve diagram obtained during a Beginning of Life (BOL) test of the battery cell, and the dashed curve represents a voltage-state of charge characteristic curve diagram obtained during an End of Life (EOL) test of the battery cell. When the state of charge at the end of charging of the battery cell is determined using a set open-circuit voltage threshold (e.g., 3.2 V), a state of charge SOCBOL determined according to the solid curve of the BOL test of the battery cell is 15%, and a state of charge SOCEOL determined according to the dashed curve of the EOL test of the battery cell is 21%. If the state of charge is still estimated at the end of the life of the battery cell using the battery capacity state of health SOHCBOL obtained during the BOL test, a deviation of 6% will occur between the estimated state of charge (i.e., 15%) and the actual state of charge (i.e., 21%).

[0032] As shown in FIG. 2, the voltage-state of charge characteristic curve of the battery cell usually has a plurality of voltage plateau regions, and there is usually a region within which the voltage changes more rapidly between adjacent voltage plateaus. A point at which the voltage changes most rapidly (that is, the maximum slope) within the region is a voltage plateau inflection point, wherein a point with a higher voltage is referred to as a high-voltage plateau inflection point, and a point with a lower voltage is referred to as a low-voltage plateau inflection point. Here, the preset state of charge threshold SOCt may be determined on the basis of an operating point of a vehicle power system (including a battery power system, a hybrid system, etc.), or the preset state of charge threshold SOCt may be determined on the basis of a relaxation voltage capacity of the first battery cell. Here, the preset state of charge threshold SOCt is greater than a state of charge value SOCL at which the low-voltage plateau inflection point appears in the voltage-capacity characteristic curve of the first battery cell and less than a state of charge value SOCH at which the high-voltage plateau inflection point appears. Considering that the voltage-state of charge characteristic curve of the battery cell will continuously move with the updated estimated state of health of the battery cell, the preset state of charge threshold SOCt may be set to be greater than the state of charge value SOCEOLL at which the low-voltage plateau inflection point appears determined according to the EOL test of the battery cell, and less than the state of charge value SOCBOLH at which the high-voltage plateau inflection point appears determined according to the BOL test of the battery cell.

[0033] During each charging and discharging cycle, at the end of charging or at the beginning of discharging of one charging and discharging cycle, an open-circuit voltage of the first battery cell may be measured, and the estimated state of charge SOCPof the first battery cell at the end of charging or at the beginning of discharging may be determined, for example, by means of the opencircuit voltage method, according to the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of the first battery cell determined in the previous charging and discharging cycle. An end-of-discharge condition for a charging and discharging cycle is likewise dependent on the state of charge estimated on the basis of the voltagestate of charge characteristic curve, for example, in the following manner: during the discharging process, for example, the open-circuit voltage of the first battery cell is acquired at a predetermined time interval, and the estimated state of charge of the first battery cell at an acquisition moment is determined by means of the open-circuit voltage method according to the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of the first battery cell determined in the previous charging and discharging cycle, and the battery cells of the battery pack are controlled to stop discharging when the estimated state of charge reaches the preset state of charge threshold SOCt (e.g., 15%).

[0034] In step S3, a battery capacity state of health SOHCc of the first battery cell is calculated on the basis of a discharge amount Q and an estimated state of charge variation ASOCp of the first battery cell during the discharging process, and the estimated battery capacity state of health SOHCp of the first battery cell is corrected by means of the calculated battery capacity state of health SOHCc.

[0035] Here, during the discharging process in which the estimated state of charge of the first battery cell decreases to the preset state of charge threshold SOCt, the change process of the discharge current over time may be recorded, and the discharge amount Q of the first battery cell during the discharging process is calculated by means of an ampere-hour integration method on the basis of the change process I(t) of the discharge current of the first battery cell from a discharge starting moment tstart to a discharge ending moment tend over time, a calculation formula being, for example:

[0036] Therefore, the battery capacity state of health SOHCc of the first battery cell, that is, the ratio of the calculated discharge amount Q to the estimated state of charge variation ASOCp of the first battery cell during the discharging process, may be calculated by means of the following formula:

[0037] SOHCc = Q / ASOCp

[0038] Here, the estimated battery capacity state of health SOHCp of the first battery cell may be corrected by replacing, for example, the estimated battery capacity state of health SOHCp of the first battery cell currently stored in the battery management system 1 with an average value of the calculated battery capacity state of health SOHCc and the estimated battery capacity state of health SOHCp of the first battery cell.

[0039] As an example, during a first charging and discharging cycle of the first battery cell, it is assumed that an initial value of the estimated battery capacity state of health SOHCp of the first battery cell stored in the battery management system 1 is 100%, and the estimated state of charge of the first battery cell at the beginning of a first discharging process is equal to 100%. During the first discharging process, for example, the open-circuit voltage of the first battery cell is acquired at a predetermined time interval, the estimated state of charge of the first battery cell at the acquisition moment is determined by means of the open-circuit voltage method according to the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of 100% of the first battery cell, and the battery cells of the battery pack are controlled to stop discharging when the estimated state of charge reaches a preset state of charge threshold of 15%. Therefore, the estimated state of charge of the first battery cell decreases from 100% to 15% during the first discharging process, that is, the estimated state of charge variation ASOCp during the first discharging process is equal to 85%. Moreover, the discharge amount Q of the first battery cell is calculated by means of the ampere-hour integration method during the first discharging process, and the battery capacity state of health SOHCc can be calculated to be equal to 60% on the basis of the estimated state of charge variation ASOCp and the calculated discharge amount Q. The estimated battery capacity state of health SOHCp stored in the battery management system 1 may be corrected to be 80% by averaging the initial value of the estimated battery capacity state of health SOHCp of 100% and the battery capacity state of health SOHCc of 60% determined during the first charging and discharging cycle.

[0040] In step S4, steps SI to S3 are repeated, that is, the estimated battery capacity state of health SOHCp of the first battery cell stored in the battery management system 1 is continuously corrected by means of the charging and discharging processes of the battery pack until the deviation value between the calculated battery capacity state of health SOHCc and the estimated battery capacity state of health SOHCp of the first battery cell is less than a preset deviation threshold, thereby determining the current estimated battery capacity state of health SOHCp as a final value.

[0041] As an example, during a second charging and discharging cycle of the first battery cell, the open-circuit voltage of the first battery cell is measured at the beginning of a second discharging process, and the estimated state of charge SOCPof the first battery cell at the beginning of the second discharging process may be determined to be, for example, 80%, by means of the opencircuit voltage method according to the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of the first battery cell updated in the battery management system 1 (i.e., the estimated battery capacity state of health SOHCp of 80% corrected during the first charging and discharging cycle). Then, the open-circuit voltage of the first battery cell is similarly acquired at the predetermined time interval during the second discharging process, the estimated state of charge of the first battery cell at the acquisition moment is determined by means of the open-circuit voltage method according to the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of 80% of the first battery cell, and the battery cell of the battery pack is controlled to stop discharging when the estimated state of charge reaches the preset state of charge threshold of 15%. Therefore, the estimated state of charge of the first battery cell decreases from 80% to 15% during the second discharging process, that is, the estimated state of charge variation ASOCp during the second discharging process is equal to 65%. Moreover, the discharge amount Q of the first battery cell is calculated by means of the ampere-hour integration method during the second discharging process, and the battery capacity state of health SOHCc may be calculated to be equal to 65% on the basis of the estimated state of charge variation ASOCp and the calculated discharge amount Q. The estimated battery capacity state of health SOHCp stored in the battery management system 1 may be corrected to be 72.5% by averaging the battery capacity state of health SOHCc of 80% updated during the first charging and discharging cycle and the battery capacity state of health SOHCc of 65% calculated during the second charging and discharging cycle.

[0042] During a third charging and discharging cycle of the first battery cell, the open-circuit voltage of the first battery cell is measured at the beginning of a third discharging process, and the estimated state of charge SOCPof the first battery cell at the beginning of the third discharging process may be determined to be, for example, 85%, by means of the open-circuit voltage method according to the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of the first battery cell updated in the battery management system 1 (i.e., the estimated battery capacity state of health SOHCp of 72.5% corrected during the second charging and discharging cycle). Then, the open-circuit voltage of the first battery cell is similarly acquired at the predetermined time interval during the third discharging process, the estimated state of charge of the first battery cell at the acquisition moment is determined by means of the open-circuit voltage method according to the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of 72.5% of the first battery cell, and the battery cell of the battery pack is controlled to stop discharging when the estimated state of charge reaches the preset state of charge threshold of 15%. Therefore, the estimated state of charge of the first battery cell decreases from 80% to 15% during the third discharging process, that is, the estimated state of charge variation ASOCp during the third discharging process is equal to 70%. Moreover, the discharge amount Q of the first battery cell is calculated by means of the ampere-hour integration method during the third discharging process, and the battery capacity state of health SOHCc may be calculated to be equal to 61.5% on the basis of the estimated state of charge variation ASOCp and the calculated discharge amount Q. The estimated battery capacity state of health SOHCPstored in the battery management system 1 may be corrected to be 67%, which gradually approaches the actual battery capacity state of health of 65% of the first battery cell, by averaging the battery capacity state of health SOHCc of 72.5% updated during the second charging and discharging cycle and the battery capacity state of health SOHCc of 61.5% calculated during the third charging and discharging cycle.

[0043] The charging and discharging processes of the battery pack are cyclically executed, and the execution of steps SI to S3 is stopped when the deviation value between the calculated battery capacity state of health SOHCc and the estimated battery capacity state of health SOHCPof the first battery cell is less than the preset deviation threshold, thereby determining the current estimated battery capacity state of health SOHCPas the final value.

[0044] In addition, considering various degrees of aging of the battery cells of the battery pack, there is also a problem of charging imbalance of individual battery cells during the charging process of the battery pack. Therefore, during the charging process of the battery pack, that is, during the charging process of each charging and discharging cycle, individual battery cells of the battery pack may also be balanced, thereby accelerating the convergence speed of the deviation value between the calculated battery capacity state of health SOHCc and the estimated battery capacity state of health SOHCp.

[0045] According to the present application, the capacity of the battery cell is efficiently and accurately calculated by means of the regression algorithm during the charging and discharging cycle of the battery pack, and the battery capacity state of health stored in the battery management system is corrected until the calculated battery capacity state of health converges, thereby eliminating the influence and error caused by the capacity of a battery cell that has not been updated for a long time on the calculation of the state of charge of the battery cell and various control processes based on the state of charge of the battery cell without adding hardware testing equipment. Additionally, it should be noted that the step numbers described herein do not necessarily represent an order, but are merely reference numerals. The order may be changed according to a specific situation, so long as the technical objective of the present application can be achieved.

[0046] FIG. 3 shows a block diagram of a battery management system 1 according to an exemplary embodiment of the present application.

[0047] The battery management system may include the following components:

[0048] - at least one processor 11 ; and

[0049] - a memory 12 communicatively connected to the at least one processor 11, wherein instructions processable by the at least one processor 11 are stored on the memory, and the instructions, when processed by the at least one processor 11 , implement the method according to the present application.

[0050] Although the specific implementations of the present application have been described in detail herein, they are merely provided for the purpose of explanation, and should not be considered as limiting the scope of the present application. Various replacement solutions and modification solutions may be provided without departing from the core and scope of the present application.

Claims

CLAIMS1. A method for estimating the capacity of a battery cell, the method comprising: step SI: charging a battery pack comprising a plurality of battery cells until the charging of the battery pack is ended; step S2: discharging the battery cells of the battery pack until an estimated state of charge SOCp of a first battery cell of the battery pack decreases to a preset state of charge threshold SOCt, wherein the estimated state of charge SOCPof the first battery cell is determined on the basis of an estimated battery capacity state of health SOHCp of the first battery cell; step S3: calculating a battery capacity state of health SOHCc of the first battery cell on the basis of a discharge amount Q and an estimated state of charge variation ASOCPof the first battery cell during the discharging process, and correcting the estimated battery capacity state of health SOHCp of the first battery cell by means of the calculated battery capacity state of health SOHCc; and step S4: repeating steps SI to S3 until a deviation value between the calculated battery capacity state of health SOHCc and the estimated battery capacity state of health SOHCp of the first battery cell is less than a preset deviation threshold.

2. The method according to claim 1, wherein the estimated battery capacity state of health SOHCp of the first battery cell is corrected by replacing the estimated battery capacity state of health SOHCp of the first battery cell with an average value of the calculated battery capacity state of health SOHCc and the estimated battery capacity state of health SOHCp of the first battery cell.

3. The method according to claim 1 or 2, wherein during the charging process of the battery pack, individual battery cells of the battery pack are balanced.

4. The method according to claim 1 or 2, wherein the preset state of charge threshold SOCt is determined on the basis of an operating point of a vehicle power system and / or a relaxation voltage capacity of the first battery cell, and the preset state of charge threshold is greater than a state ofcharge value SOCL at which a low-voltage plateau inflection point appears in a voltage-capacity characteristic curve of the first battery cell and less than a state of charge value SOCH at which a high-voltage plateau inflection point appears.

5. The method according to claim 1 or 2, wherein an open-circuit voltage of the first battery cell is measured when the battery cells of the battery pack start discharging, and the estimated state of charge SOCPof the first battery cell at the beginning of discharging is determined by means of an open-circuit voltage method on the basis of a voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of the first battery cell; and / or during the discharging process of the battery pack, the open-circuit voltage of the first battery cell is acquired, the estimated state of charge of the first battery cell is determined by means of the open-circuit voltage method on the basis of the voltage-state of charge characteristic curve corresponding to the estimated battery capacity state of health SOHCp of the first battery cell, and the battery cells of the battery pack are controlled to stop discharging when the estimated state of charge reaches the preset state of charge threshold SOCt; and / or on the basis of a change process of a discharge current of the first battery cell over time, the discharge amount Q of the first battery cell during the discharging process is calculated by means of an ampere-hour integration method.

6. The method according to claim 1 or 2, wherein when the first battery cell in the battery pack satisfies a predetermined capacity estimation triggering condition, execution of steps SI to S4 is triggered to estimate the battery capacity state of health of the first battery cell, the capacity estimation triggering condition being related to a time interval for executing capacity estimation.

7. The method according to claim 1 or 2, wherein when one or more battery cells in the battery pack are fully charged, or in response to receiving a control instruction to stop charging, the battery pack is controlled to end charging.

8. A battery management system (1), wherein the battery management system (1) comprises the following components: at least one processor (11); and a memory (12) communicatively connected to the at least one processor (11), wherein instructions processable by the at least one processor (11) are stored on the memory, and the instructions, when processed by the at least one processor (11), implement the method according to any one of claims 1 to 7.

9. A vehicle, comprising the battery management system (1) according to claim 8.

10. A computer program product, such as a computer-readable program carrier, comprising or storing computer program instructions that, when executed by a processor, at least assist in implementing steps of the method according to any one of claims 1 to 7.

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