CN116299116A

CN116299116A - OCV-SOC calibration method of energy storage system and electronic equipment

Info

Publication number: CN116299116A
Application number: CN202310098085.0A
Authority: CN
Inventors: 洪灏灏; 石祥建; 侯炜; 徐光福; 王万纯; 储海军; 姜淼; 魏阳
Original assignee: NR Electric Co Ltd; NR Engineering Co Ltd; Changzhou NR Electric Power Electronics Co Ltd
Current assignee: NR Electric Co Ltd; NR Engineering Co Ltd; Changzhou NR Electric Power Electronics Co Ltd
Priority date: 2023-02-03
Filing date: 2023-02-03
Publication date: 2023-06-23

Abstract

The invention discloses an OCV-SOC calibration method of an energy storage system, which aims at the problems that SOC deviation is gradually increased due to accumulated errors of an ampere-hour integration method, and each unit of a medium-sized and large-sized energy storage system is difficult to achieve full charge and discharge at the same time to calibrate SOC periodically, and adopts an OCV table look-up method to calibrate SOC under a standing working condition. In addition, aiming at the influences of long standing time, low calibration probability, charge and discharge states, battery cell aging, battery cell temperature, hysteresis effect and the like required by the open circuit voltage approaching the OCV, the OCV-SOC calibration method under different standing working conditions of the energy storage system is comprehensively considered, the system SOC calibration probability is increased, and the system SOC estimation precision is improved.

Description

OCV-SOC calibration method of energy storage system and electronic equipment

Technical Field

The invention belongs to the field of electrochemical energy storage, and particularly relates to an OCV-SOC calibration method of an energy storage system and electronic equipment.

Background

The state of charge (SOC) of the energy storage system characterizes the residual capacity of the system, is a core parameter of a battery management system, and high-precision SOC is critical to efficient and stable operation of the energy storage system. At present, an energy storage system generally adopts a method for checking actual capacity through full charge/full discharge and dynamically estimating SOC through ampere-hour integration. However, for a medium-sized or large-sized energy storage system, whether in a parallel type or series type topology, each unit in the system is difficult to reach a full charge/full discharge state at the same time, and the integral accumulated error can cause the SOC deviation to be gradually increased, so that the safe and stable operation of the system is seriously affected.

The OCV-SOC calibration is a method of calibrating the SOC by using an inherent relationship between the open-cell voltage OCV and the SOC, and by approximating the cell terminal voltage obtained by standing for a long period to be equal to the OCV and by looking up a table. The OCV-SOC calibration can provide an accurate initial value of the SOC for an ampere-hour integration method, and meanwhile, the error accumulated by integration is eliminated, so that the accuracy of system SOC estimation is improved. Taking lithium iron phosphate cells as an example of the primary use of electrochemical energy storage systems, a typical OCV calibration curve is shown in fig. 5. When the OCV calibration curve is different under different operation conditions, factors such as the temperature of the battery cell, the standing time, the charge and discharge state before standing, the aging of the battery cell and the like can influence the OCV calibration curve, so that the accuracy is influenced by adopting the existing OCV-SOC calibration method. The OCV-SOC calibration can achieve higher accuracy only when the test conditions used to calibrate the OCV calibration curve are close to the current operating conditions.

Disclosure of Invention

The invention aims to provide an OCV-SOC calibration method of an energy storage system, which is suitable for an electrochemical energy storage system adopting a lithium iron phosphate cell, and can reduce the SOC estimation deviation of the energy storage system, optimize the control performance and improve the operation safety of the system by matching with an ampere-hour integration method.

According to an aspect of the present invention, there is provided an OCV-SOC calibration method for an energy storage system, including:

acquiring a medium-term OCV calibration curve and a long-term OCV calibration curve of the energy storage system;

observing the charge and discharge process in real time, dynamically identifying the working condition of the effective point of the middle calibration, and selecting an OCV calibration curve;

measuring the voltage of the battery cell to obtain a calibration point OCV, partitioning the OCV calibration curve, and carrying out SOC calibration by combining the current capacity information of the battery cell;

and analyzing the SOC calibration deviation, and judging the reliability of the SOC calibration result.

According to some embodiments, the method for obtaining the middle OCV calibration curve and the long-term OCV calibration curve is as follows:

obtaining temperature T ₀ Under the condition of standing t ₁ Time charging OCV curve and discharging OCV curve are used as middle OCV calibration curve, and the symmetry of charging OCV and discharging OCV under the same standing time is utilized to approximate the middle line of the two curves as standing t ₂ A long-term OCV calibration curve of time; wherein the temperature T ₀ For the cell stabilizing temperature under the standing condition, the standing time t ₁ 、t ₂ According to the actual working condition, t ₂ Set to be greater than t ₁ Is 2 times as large as the above.

According to some embodiments, the dynamic identification mid-term calibration effective point working condition selection calibration curve specifically includes:

firstly, obtaining initial capacity SOC of current charge-discharge period ₀ In the charge-discharge period, calculating the SOC in real time by an ampere-hour integration method, and dynamically updating the maximum capacity SOC in the process _max Minimum capacity SOC _min ；

When the charging state is the current state, if the current capacity meets the relation shown in the formula (1), the OCV calibration of the middle charging is judged to be effective, and the OCV calibration curve of the middle charging is selected as the calibration curve;

when the current capacity is in a discharging state, if the current capacity meets the relation shown in the formula (2), judging that the OCV calibration of the middle-stage discharging is effective, and selecting an OCV calibration curve of the middle-stage discharging as a calibration curve;

when equation (1) is not satisfied in the charged state and equation (2) is not satisfied in the discharged state, the long-term OCV calibration curve is selected as the calibration curve.

According to some embodiments, when the mid-charge/discharge OCV calibration effective condition is satisfied in the rest state, mid-charge/discharge OCV calibration will be waited for when the rest reaches t ₁ Time and the temperature of the battery cell is stabilized at T ₀ And when the charging/discharging OCV calibration curve is used, the corresponding medium-term charging/discharging OCV calibration curve is called for calibration.

According to some embodiments, when the medium charge/discharge OCV calibration effective condition is not satisfied in the rest state, the long-term OCV calibration is waited for, when the rest state reaches t ₂ Time and the temperature of the battery cell is stabilized at T ₀ And when the OCV calibration curve is called for calibration.

According to some embodiments, the partitioning the OCV calibration curve and performing SOC calibration in combination with current capacity information of the battery cell specifically includes:

partitioning the OCV calibration curve to define an OCV corresponding to an SOC of 80% as the OCV _TH When OCV is more than or equal to OCV _TH OCV is high SOC region<OCV _TH Is a low SOC region;

according to the calibration point OCV obtained by measuring the cell voltage, looking up a table to obtain an SOC value SOC corresponding to the OCV _curve And meanwhile, according to the area where OCV is located, the cell is obtained by calibration according to the formula (3)The SOC at the front-end capacity is,

wherein Q is ₀ For initial rated capacity of cell, Q _a Is the current capacity of the battery cell.

According to some embodiments, the specific method for analyzing the SOC calibration deviation and determining the reliability of the SOC calibration result is as follows:

the battery management system cell voltage acquisition precision is set according to the measurement error delta V, and the SOC corresponding to (OCV-delta V) is obtained by looking up a table _{curve_L} And (OCV+DeltaV) corresponding SOC _{curve_H} ；

When the relation shown in the formula (4) is satisfied, the SOC calibration result obtained by the OCV-SOC calibration is determined to be reliable,

SOC _{curve_H} -SOC _{curve_L} <ΔSOC _TH (4)

wherein ΔSOC _TH The effective tolerance is calibrated for OCV-SOC.

According to some embodiments, after one OCV-SOC calibration is completed, the next waiting period is immediately entered, and when the standing time condition is satisfied again, the next OCV-SOC calibration is performed again; meanwhile, when the first calibration after standing is the middle-stage charge/discharge OCV calibration, the middle-stage charge/discharge OCV calibration is set to be invalid after the first calibration.

According to another aspect of the present invention, there is provided an electronic apparatus including:

a processor; a memory and a computer program stored in the memory and executable on the processor, the processor implementing the method of any one of the above methods when executing the computer program.

The invention provides an OCV-SOC calibration method of an energy storage system, which is characterized in that the working condition of a calibration effective point is dynamically identified to accurately match a corresponding OCV calibration curve, the effectiveness of OCV-SOC calibration in the whole life cycle of a battery cell is ensured by considering the problem of capacity loss caused by battery cell aging, and meanwhile, the calibration is triggered under consideration of different standing time to improve the probability of OCV-SOC calibration; by comprehensively considering the influence of various factors on the OCV, the accuracy of OCV-SOC calibration is improved.

Drawings

FIG. 1 shows a general schematic of an energy storage system OCV-SOC calibration method;

FIG. 2 is a schematic flow chart showing the selection of a corresponding OCV calibration curve for calibration;

FIG. 3 shows a flow diagram of a method for efficiently performing OCV-SOC calibration;

FIG. 4 is a schematic diagram of a mid-term calibration effective interval determined under typical energy storage conditions;

FIG. 5 shows a typical cell medium-to-long term OCV calibration curve;

fig. 6 shows a block diagram of an electronic device according to an example embodiment of the present application.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as 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 concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and thus a repetitive description thereof will be omitted.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, devices, steps, etc. In other instances, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

The block diagrams depicted in the figures are merely functional entities and do not necessarily correspond to physically separate entities. That is, the functional entities may be implemented in software, or in one or more hardware modules or integrated circuits, or in different networks and/or processor devices and/or microcontroller devices.

The flow diagrams depicted in the figures are exemplary only, and do not necessarily include all of the elements and operations/steps, nor must they be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the order of actual execution may be changed according to actual situations.

Those skilled in the art will appreciate that the drawings are schematic representations of example embodiments and that the modules or flows in the drawings are not necessarily required to practice the invention and therefore should not be taken to limit the scope of the invention.

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

FIG. 1 shows a general schematic diagram of an energy storage system OCV-SOC calibration method, including:

s110: acquiring a medium-term OCV calibration curve and a long-term OCV calibration curve of the energy storage system;

s120: observing the charge and discharge process in real time, dynamically identifying the working condition of the effective point of the middle calibration, and selecting an OCV calibration curve;

s130: measuring the voltage of the battery cell to obtain a calibration point OCV, partitioning the OCV calibration curve, and carrying out SOC calibration by combining the current capacity information of the battery cell;

s140: and analyzing the SOC calibration deviation, and judging whether the SOC calibration result is reliable or not.

In a preferred embodiment, the method for obtaining the middle-term OCV calibration curve and the long-term OCV calibration curve is as follows:

obtaining temperature T ₀ Under the condition of standing t ₁ Time of charge OCV curveA discharge OCV curve, which is a mid-term OCV calibration curve, wherein the symmetry of the charge OCV and the discharge OCV at the same rest time is used to approximate the center line of the two curves as a rest t ₂ A long-term OCV calibration curve of time, under the long-term standing condition, the polarization effect of the battery cell gradually disappears, and the influence of the charge and discharge state before standing on the OCV is ignored; the heat management system with complete energy storage is generally configured, and the battery cell can be stabilized at a certain temperature under the standing condition, the temperature T ₀ To stabilize the temperature of the battery cell under the standing condition, T ₀ Typically 25 ℃; rest time t ₁ 、t ₂ According to the actual working condition, t ₂ Set to be greater than t ₁ Is 2 times, t ₁ Can be set to 3h, t ₂ Can be set to 12h.

In a preferred embodiment, the dynamic identification medium-term calibration effective point working condition selects an OCV calibration curve, specifically:

When the charging state is the current state, if the current capacity meets the relation shown in the formula (1), judging that the OCV calibration of the middle-stage charging is effective, namely setting COCV_flg to 1, and selecting an OCV calibration curve of the middle-stage charging as a calibration curve;

when the current capacity is in a discharging state, if the current capacity meets the relation shown in the formula (2), judging that the OCV calibration of the middle-stage discharge is effective, namely setting DOCV_flg to 1, and selecting an OCV calibration curve of the middle-stage discharge as a calibration curve;

under mid-term rest conditions, the polarization effect of the cell still exists, as shown in FIG. 5, which shows a typical cell medium-to-long term OCV calibration curve, the sameUnder the condition of SOC, after charge or discharge, standing for t ₁ The cell voltages in time are different, and different OCV calibration curves need to be called for calibration.

When equation (1) is not satisfied in the charged state and equation (2) is not satisfied in the discharged state, the long-term OCV calibration curve is selected as the calibration curve. FIG. 2 shows a schematic flow chart for selecting a corresponding OCV calibration curve for calibration. Because the hysteresis effect of the battery core exists, after the battery core is subjected to a short-time discharging process, the charging OCV can be adopted to calibrate the SOC of the battery only when the charging electric quantity can be balanced with the partial discharging electric quantity, and the like.

In the preferred embodiment, when the condition for the middle-stage charge/discharge OCV calibration is satisfied in the rest state, the middle-stage charge/discharge OCV calibration is waited for, and when the rest state reaches t ₁ Time t ₁ Can be set to 3h, and the temperature of the battery cell is stabilized at T ₀ At the time T ₀ Typically 25 c, i.e., the corresponding mid-charge/discharge OCV calibration curve is called for calibration.

In the preferred embodiment, when the condition for the mid-charge/discharge OCV calibration is not satisfied in the rest state, the long-term OCV calibration is waited for, and when the rest state reaches t ₂ Time t ₂ Can be set to 12h, and the temperature of the battery cell is stabilized at T ₀ And when the OCV calibration curve is called for calibration. Fig. 4 is a schematic diagram showing a method for determining an effective interval of middle calibration under a typical energy storage condition, where the method shown in fig. 1 can be used to obtain an interval meeting the condition of middle charge/discharge calibration, so as to avoid the influence of the hysteresis effect of a battery cell on the accuracy of OCV-SOC calibration, and the middle OCV-SOC calibration can be performed only after a certain time of standing in the illustrated interval of effective calibration.

FIG. 3 shows a flow chart of a method for effectively performing OCV-SOC calibration. In a preferred embodiment, the partitioning the OCV calibration curve and performing SOC calibration in combination with current capacity information of the battery cell is specifically:

partitioning the OCV calibration curve to define an OCV corresponding to an SOC of 80% as the OCV _TH When OCV is more than or equal to OCV _TH OCV is high SOC region<OCV _TH Is low inAn SOC region; when OCV>OCV _TH The cell is nearly full.

According to the calibration point OCV obtained by measuring the cell voltage, looking up a table to obtain an SOC value SOC corresponding to the OCV _curve Meanwhile, according to the area where the OCV is located, the SOC of the battery cell under the current capacity is obtained by calibration according to the formula (3),

Fig. 5 shows a typical cell medium-to-long term OCV calibration curve. As the overall shape of the OCV calibration curve in FIG. 5 is not changed along with the aging of the battery cells, but the high SOC area is gradually shifted leftwards, the method of the application considers the problem of electric quantity loss caused by the aging of the battery cells, and is suitable for the OCV-SOC calibration of the battery cells in the whole life cycle.

In a preferred embodiment, the specific method for analyzing the SOC calibration deviation and determining whether the SOC calibration result is reliable is as follows:

SOC _{curve_H} -SOC _{curve_L} <ΔSOC _TH (4)

wherein ΔSOC _TH The effective tolerance is calibrated for OCV-SOC.

And (3) when the equation (4) is not satisfied, judging that the SOC calibration result obtained by the calibration is large in error and unreliable, and discarding the calibration result.

In a preferred embodiment, after one OCV-SOC calibration is completed, the next waiting period is immediately entered, and when the standing time condition is satisfied again, the next OCV-SOC calibration is performed again; meanwhile, when the first calibration is the middle-stage charge/discharge OCV calibration after standing, the middle-stage charge/discharge OCV calibration is set to be invalid after the first calibration, so that the repeated entering of the middle-stage charge/discharge OCV calibration under the long-term standing working condition is avoided.

In fact, when the energy storage system operates, the standing time is short, the middle-term OCV calibration is normally triggered only once, when the energy storage system is in a fault shutdown or power failure overhaul, the long-term OCV calibration is periodically carried out at the moment, the SOC is continuously corrected, and when the system is charged and discharged again, the accurate initial value of the SOC is ensured.

In summary, according to the technical scheme of the application, the working conditions of the calibration effective points are dynamically identified to accurately match the corresponding OCV calibration curve, the effectiveness of OCV-SOC calibration in the whole life cycle of the battery cell is ensured by considering the problem of capacity loss caused by battery cell aging, and meanwhile, the calibration is triggered under different standing time to improve the probability of OCV-SOC calibration; by comprehensively considering the influence of various factors on the OCV, the accuracy of OCV-SOC calibration can be improved.

The following describes electronic device embodiments of the present application that may be used to perform method embodiments of the present application. For details not disclosed in the embodiments of the present electronic device, reference may be made to the embodiments of the method of the present application.

The electronic device shown in fig. 6 may perform an OCV-SOC calibration method for the energy storage system according to an embodiment of the present application as described above.

An electronic device 600 according to this embodiment of the present application is described below with reference to fig. 6. The electronic device 600 shown in fig. 6 is merely an example, and should not be construed as limiting the functionality and scope of use of embodiments of the present application.

As shown in fig. 6, the electronic device 600 is in the form of a general purpose computing device. Components of electronic device 600 may include, but are not limited to: at least one processing unit 610, at least one memory unit 620, a bus 630 connecting the different system components (including the memory unit 620 and the processing unit 610), a display unit 640, etc.

In which a storage unit stores program code that can be executed by the processing unit 610, such that the processing unit 610 performs the methods described herein according to various exemplary embodiments of the present application.

The storage unit 620 may include readable media in the form of volatile storage units, such as Random Access Memory (RAM) 6201 and/or cache memory unit 6202, and may further include Read Only Memory (ROM) 6203.

The storage unit 620 may also include a program/utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including, but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of which may include an implementation of a network environment.

Bus 630 may be a local bus representing one or more of several types of bus structures including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or using any of a variety of bus architectures.

The electronic device 600 may also communicate with one or more external devices 700 (e.g., keyboard, pointing device, bluetooth device, etc.), one or more devices that enable a user to interact with the electronic device 600, and/or any device (e.g., router, modem, etc.) that enables the electronic device 600 to communicate with one or more other computing devices. Such communication may occur through an input/output (I/O) interface 650. Also, electronic device 600 may communicate with one or more networks such as a Local Area Network (LAN), a Wide Area Network (WAN), and/or a public network, such as the Internet, through network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 over the bus 630. It should be appreciated that although not shown, other hardware and/or software modules may be used in connection with electronic device 600, including, but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, data backup storage systems, and the like.

From the above description of embodiments, those skilled in the art will readily appreciate that the example embodiments described herein may be implemented in software, or may be implemented in software in combination with the necessary hardware. The technical solution according to the embodiments of the present application may be embodied in the form of a software product, which may be stored in a non-volatile storage medium (may be a CD-ROM, a usb disk, a mobile hard disk, etc.) or on a network, and includes several instructions to cause a computing device (may be a personal computer, a server, or a network device, etc.) to perform the above-described method according to the embodiments of the present application.

The software product may employ any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a combination of any of the foregoing. More specific examples (a non-exhaustive list) of the readable storage medium would include the following: an electrical connection having one or more wires, a portable disk, a hard disk, random Access Memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

The computer readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, with readable program code embodied therein. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A readable storage medium may also be any readable medium that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a readable storage medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Program code for carrying out operations of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, C++ or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computing device, partly on the user's device, as a stand-alone software package, partly on the user's computing device, partly on a remote computing device, or entirely on the remote computing device or server. In the case of remote computing devices, the remote computing device may be connected to the user computing device through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computing device (e.g., connected via the Internet using an Internet service provider).

Those skilled in the art will appreciate that the modules may be distributed throughout several devices as described in the embodiments, and that corresponding variations may be implemented in one or more devices that are unique to the embodiments. The modules of the above embodiments may be combined into one module, or may be further split into a plurality of sub-modules.

Exemplary embodiments of the present application are specifically illustrated and described above. It is to be understood that this application is not limited to the details of construction, arrangement or method of implementation described herein; on the contrary, the application is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. An OCV-SOC calibration method for an energy storage system is characterized in that,

and analyzing the SOC calibration deviation, and judging whether the SOC calibration result is reliable or not.

2. The method of claim 1, wherein the medium-term OCV calibration curve and the long-term OCV calibration curve are obtained by:

3. The OCV-SOC calibration method of claim 1, wherein the dynamic identification of the mid-calibration effective point conditions selects an OCV calibration curve, specifically:

4. A method of OCV-SOC calibration for an energy storage system as defined in claim 3, wherein:

when the effective condition of the OCV calibration of the middle-stage charge/discharge is satisfied in the standing state, the OCV calibration of the middle-stage charge/discharge is waited to be carried out, and when the standing state reaches t ₁ Time and the temperature of the battery cell is stabilized at T ₀ And when the charging/discharging OCV calibration curve is used, the corresponding medium-term charging/discharging OCV calibration curve is called for calibration.

5. A method of OCV-SOC calibration for an energy storage system as defined in claim 3, wherein:

when the effective condition of the OCV calibration of the medium-term charge/discharge is not satisfied in the standing state, the long-term OCV calibration is waited for, and when the standing state reaches t ₂ Time and the temperature of the battery cell is stabilized at T ₀ And when the OCV calibration curve is called for calibration.

6. The OCV-SOC calibration method of claim 1, wherein the partitioning the OCV calibration curve and performing SOC calibration in combination with current capacity information of the battery cell comprises:

wherein Q is ₀ For initial rating of the cellCapacity, Q _a Is the current capacity of the battery cell.

7. The OCV-SOC calibration method for an energy storage system of claim 1, wherein the specific method for analyzing the SOC calibration deviation and determining whether the SOC calibration result is authentic is as follows:

SOC _{curve_H} -SOC _{curve_L} <ΔSOC _TH (4)

wherein ΔSOC _TH The effective tolerance is calibrated for OCV-SOC.

8. The method for OCV-SOC calibration of an energy storage system of claim 1, wherein:

after one OCV-SOC calibration is completed, the next waiting period is immediately entered, and when the standing time condition is met again, the next OCV-SOC calibration is performed; meanwhile, when the first calibration after standing is the middle-stage charge/discharge OCV calibration, the middle-stage charge/discharge OCV calibration is set to be invalid after the first calibration.

9. An electronic device, comprising:

a processor;

a memory, and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the method of any of the preceding claims 1-8 when executing the computer program.