Energy storage system ocv-soc calibration method and electronic device

Abstract

The application discloses an OCV-SOC calibration method for an energy storage system, and aims at gradually increasing SOC deviation caused by cumulative error of ampere-hour integration method, and the problem that it is difficult for each unit of a medium-large energy storage system to reach full charging and full discharging at the same time to periodically calibrate SOC. The SOC is calibrated by OCV table lookup method under static condition. In addition, in view of long static time required for open-circuit voltage to approach OCV, low calibration probability, and influences of charging and discharging states, cell aging, cell temperature and hysteresis effect, the OCV-SOC calibration method under different static conditions of the energy storage system is comprehensively considered, the calibration probability of the system SOC is increased, and the estimation accuracy of the system SOC is improved.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage, and specifically relates to an OCV-SOC calibration method and electronic equipment for an energy storage system. Background Technology

[0002] The State of Charge (SOC) of an energy storage system characterizes the system's remaining capacity and is a core parameter of the battery management system. High-precision SOC is crucial for the efficient and stable operation of energy storage systems. Currently, energy storage systems typically use full charge / full discharge verification of actual capacity and dynamic SOC estimation through ampere-hour integration. However, for medium to large-scale energy storage systems, regardless of whether the topology is parallel or series, it is difficult for all units within the system to simultaneously reach full charge / full discharge states. Furthermore, the cumulative error from integration leads to a gradual increase in SOC deviation, severely impacting the safe and stable operation of the system.

[0003] OCV-SOC calibration utilizes the inherent relationship between the cell's open-circuit voltage (OCV) and state of charge (SOC) to approximate the battery terminal voltage obtained after long-term static storage as equal to the OCV, and then calibrates the SOC by referring to a table. OCV-SOC calibration can provide an accurate initial SOC value for the ampere-hour integration method, while eliminating the error of integration accumulation, thereby improving the accuracy of system SOC estimation. Taking lithium iron phosphate cells, which are mainly used in electrochemical energy storage systems, as an example, a typical OCV calibration curve is shown below. Figure 5 As shown, when OCV calibration curves differ under different operating conditions, factors such as cell temperature, resting time, charge / discharge state before resting, and cell aging can all affect the OCV calibration curve, thus impacting the accuracy of existing OCV-SOC calibration methods. Only when the test conditions used to calibrate the OCV calibration curve are close to the current operating conditions can OCV-SOC calibration achieve high accuracy. Summary of the Invention

[0004] This invention aims to provide an OCV-SOC calibration method for energy storage systems, applicable to electrochemical energy storage systems using lithium iron phosphate cells. Combined with the ampere-hour integration method, it can reduce the SOC estimation deviation of the energy storage system, optimize control performance, and improve system operation safety.

[0005] According to one aspect of the present invention, an OCV-SOC calibration method for an energy storage system is provided, comprising:

[0006] Obtain the mid-term and long-term OCV calibration curves of the energy storage system;

[0007] Real-time monitoring of the charging and discharging process, dynamic identification of effective working conditions for mid-term calibration, and selection of the OCV calibration curve;

[0008] The calibration point OCV is obtained by measuring the cell voltage. The OCV calibration curve is divided into sections, and SOC calibration is performed in combination with the current cell capacity information.

[0009] Analyze the SOC calibration deviation to determine the reliability of the SOC calibration results.

[0010] According to some embodiments, the method for obtaining the intermediate-term OCV calibration curve and the long-term OCV calibration curve is as follows:

[0011] Under temperature T0, the charging OCV curve and discharging OCV curve after resting for t1 are obtained as the intermediate OCV calibration curve. Taking advantage of the symmetry of the charging OCV and discharging OCV under the same resting time, the midline of the two curves is approximated as the long-term OCV calibration curve after resting for t2. Among them, temperature T0 is the stable temperature of the cell under resting conditions, and resting times t1 and t2 are determined according to the actual operating conditions, with t2 set to be more than twice that of t1.

[0012] According to some embodiments, the dynamic identification of the effective point of mid-term calibration and selection of the calibration curve specifically involves:

[0013] First, the initial capacity SOC0 of the current charge / discharge cycle is obtained. During the charge / discharge cycle, the SOC is calculated in real time using the ampere-hour integration method, and the maximum capacity SOC during the process is dynamically updated. max Minimum Capacity SOC min ;

[0014] When the current state is charging, if the current capacity satisfies the relationship shown in equation (1), the mid-term charging OCV calibration is determined to be valid, and the mid-term charging OCV calibration curve is selected as the calibration curve.

[0015]

[0016] When the current state is in discharge, if the current capacity satisfies the relationship shown in equation (2), the mid-term discharge OCV calibration is determined to be valid, and the mid-term discharge OCV calibration curve is selected as the calibration curve.

[0017]

[0018] When equation (1) is not satisfied during charging and equation (2) is not satisfied during discharging, the long-term OCV calibration curve is selected as the calibration curve.

[0019] According to some embodiments, when the conditions for valid mid-term charge / discharge OCV calibration are met under static conditions, the system will wait for mid-term charge / discharge OCV calibration to be performed. When the static period reaches t1 and the cell temperature stabilizes at T0, the corresponding mid-term charge / discharge OCV calibration curve will be called for calibration.

[0020] According to some embodiments, when the conditions for effective mid-term charge / discharge OCV calibration are not met under static conditions, long-term OCV calibration will be performed. When the static period reaches t2 and the cell temperature stabilizes at T0, the long-term OCV calibration curve will be called for calibration.

[0021] According to some embodiments, the step of partitioning the OCV calibration curve and performing SOC calibration in conjunction with the current capacity information of the battery cell specifically involves:

[0022] The OCV calibration curve is partitioned, and the OCV corresponding to a SOC of 80% is defined as the OCV. TH When OCV ≥ OCV TH For high SOC region, OCV <OCV TH This is a low SOC region;

[0023] Based on the calibration point OCV obtained from the measured cell voltage, the SOC value corresponding to this OCV is obtained by looking up the table. curve Meanwhile, based on the region where the OCV is located, the SOC of the cell at its current capacity is obtained by calibration according to equation (3).

[0024]

[0025] Where Q0 is the initial rated capacity of the battery cell, Q a This represents the current capacity of the battery cell.

[0026] According to some embodiments, the specific method for analyzing SOC calibration deviation and determining the reliability of SOC calibration results is as follows:

[0027] The accuracy of cell voltage acquisition in the battery management system is set according to the measurement error ΔV. The SOC corresponding to (OCV-ΔV) is obtained by looking up a table. curve_L and the SOC corresponding to (OCV+ΔV) curve_H ;

[0028] When the relationship shown in equation (4) is satisfied, the SOC calibration result obtained from this OCV-SOC calibration is deemed reliable.

[0029] SOC curve_H -SOC curve_L <ΔSOC TH (4)

[0030] Wherein, ΔSOC TH The allowable deviation for OCV-SOC calibration.

[0031] According to some embodiments, after completing one OCV-SOC calibration, the next waiting period begins. When the resting time condition is met again, the next OCV-SOC calibration is performed. Meanwhile, when the first calibration after resting is a mid-term charge / discharge OCV calibration, the mid-term charge / discharge OCV calibration is set to invalid after the first calibration.

[0032] According to another aspect of the present invention, an electronic device is provided, comprising:

[0033] A processor; a memory; and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method described in any one of the above methods.

[0034] This invention provides an OCV-SOC calibration method for energy storage systems. It dynamically identifies effective calibration point conditions to accurately match the corresponding OCV calibration curve. It considers the capacity loss caused by cell aging to ensure the effectiveness of OCV-SOC calibration throughout the cell's entire life cycle. At the same time, it considers triggering calibration under different resting times to increase the probability of OCV-SOC calibration. By comprehensively considering the influence of multiple factors on OCV, it improves the accuracy of OCV-SOC calibration. Attached Figure Description

[0035] Figure 1 A schematic diagram of an OCV-SOC calibration method for an energy storage system is shown.

[0036] Figure 2 A schematic diagram of a calibration process for selecting the corresponding OCV calibration curve is shown;

[0037] Figure 3 A schematic diagram of an effective OCV-SOC calibration method is shown.

[0038] Figure 4 A schematic diagram is shown for determining the effective range of mid-term calibration under typical energy storage operating conditions;

[0039] Figure 5 This shows a typical long-term OCV calibration curve for a battery cell;

[0040] Figure 6 A block diagram of an electronic device according to an example embodiment of this application is shown. Detailed Implementation

[0041] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that the invention will be thorough and complete, and the concept of the exemplary embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0042] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a full understanding of embodiments of the invention. However, those skilled in the art will recognize that the technical solutions of the invention can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of the invention.

[0043] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0044] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0045] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of exemplary embodiments, and the modules or processes in the drawings are not necessarily essential for implementing the present invention, and therefore cannot be used to limit the scope of protection of the present invention.

[0046] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Figure 1 A schematic diagram of an OCV-SOC calibration method for an energy storage system is shown, including:

[0048] S110: Obtain the mid-term and long-term OCV calibration curves of the energy storage system;

[0049] S120: Real-time monitoring of the charging and discharging process, dynamic identification of effective working conditions for mid-term calibration, and selection of OCV calibration curve;

[0050] S130: Measure the cell voltage to obtain the calibration point OCV, divide the OCV calibration curve into sections, and perform SOC calibration in conjunction with the current cell capacity information;

[0051] S140: Analyze the SOC calibration deviation to determine whether the SOC calibration results are reliable.

[0052] In a preferred embodiment, the method for obtaining the intermediate-term OCV calibration curve and the long-term OCV calibration curve is as follows:

[0053] Under temperature T0, the charging OCV curve and discharging OCV curve after resting for t1 time are obtained as the intermediate OCV calibration curve. Taking advantage of the symmetry of the charging OCV and discharging OCV under the same resting time, the midline of the two curves is approximated as the long-term OCV calibration curve after resting for t2 time. Under long-term resting conditions, the polarization effect of the cell gradually disappears, and the influence of the charging and discharging state before resting on the OCV is negligible. Energy storage is generally equipped with a complete thermal management system. Under resting conditions, the cell will stabilize at a certain temperature. Temperature T0 is the stable temperature of the cell under resting conditions, and T0 is generally 25℃. The resting time t1 and t2 are determined according to the actual operating conditions. t2 is set to be more than twice t1. t1 can be set to 3h and t2 can be set to 12h.

[0054] In a preferred embodiment, the dynamic identification of the effective point of mid-term calibration and the selection of the OCV calibration curve specifically involves:

[0055] First, the initial capacity SOC0 of the current charge / discharge cycle is obtained. During the charge / discharge cycle, the SOC is calculated in real time using the ampere-hour integration method, and the maximum capacity SOC during the process is dynamically updated. max Minimum Capacity SOC min ;

[0056] When the current state is charging, if the current capacity satisfies the relationship shown in equation (1), the mid-term charging OCV calibration is determined to be valid, that is, COCV_flg is set to 1, and the mid-term charging OCV calibration curve is selected as the calibration curve.

[0057]

[0058] When the current state is in discharge, if the current capacity satisfies the relationship shown in equation (2), the mid-term discharge OCV calibration is determined to be valid, that is, DOCV_flg is set to 1, and the mid-term discharge OCV calibration curve is selected as the calibration curve.

[0059]

[0060] Under medium-term static conditions, the polarization effect of the battery cell still exists, such as... Figure 5 The image shows a typical long-term OCV calibration curve for a battery cell. Under the same SOC conditions, the cell voltage varies after being left to stand for t1 times following charging or discharging, requiring different OCV calibration curves for calibration.

[0061] When equation (1) is not satisfied during charging and equation (2) is not satisfied during discharging, the long-term OCV calibration curve is selected as the calibration curve. Figure 2 This diagram illustrates a process for selecting a corresponding OCV calibration curve for calibration. Due to the cell hysteresis effect, after a short discharge process, the battery's SOC can only be calibrated using the charging OCV if the charging capacity can offset the discharged capacity, and vice versa.

[0062] In a preferred embodiment, when the conditions for effective mid-term charge / discharge OCV calibration are met under static conditions, the system will wait for mid-term charge / discharge OCV calibration to be performed. When the static condition reaches time t1 (which can be set to 3 hours) and the cell temperature stabilizes at T0 (which is typically 25°C), the corresponding mid-term charge / discharge OCV calibration curve will be called for calibration.

[0063] In a preferred embodiment, when the conditions for effective mid-term charging / discharging OCV calibration are not met under static conditions, long-term OCV calibration will be performed. When the static period reaches t2 (which can be set to 12 hours) and the cell temperature stabilizes at T0, the long-term OCV calibration curve will be called for calibration. Figure 4 This diagram illustrates how to determine the effective range of mid-term calibration under typical energy storage operating conditions. Figure 1 The method shown can obtain the range of operating conditions that meet the mid-term charge / discharge calibration conditions, thereby avoiding the influence of cell hysteresis effect on the OCV-SOC calibration accuracy. Mid-term OCV-SOC calibration can only be performed after a certain period of rest within the range of effective calibration shown.

[0064] Figure 3 A flowchart illustrating an effective OCV-SOC calibration method is shown. In a preferred embodiment, the step of partitioning the OCV calibration curve and performing SOC calibration in conjunction with the current cell capacity information specifically involves:

[0065] The OCV calibration curve is partitioned, and the OCV corresponding to a SOC of 80% is defined as the OCV. TH When OCV ≥ OCV TH For high SOC region, OCV <OCV TH This is the low SOC region; when OCV > OCV TH The battery cell is nearly fully charged.

[0066] Based on the calibration point OCV obtained from the measured cell voltage, the SOC value corresponding to this OCV is obtained by looking up the table. curve Meanwhile, based on the region where the OCV is located, the SOC of the cell at its current capacity is obtained by calibration according to equation (3).

[0067]

[0068] Where Q0 is the initial rated capacity of the battery cell, Q a This represents the current capacity of the battery cell.

[0069] Figure 5 This shows a typical long-term OCV calibration curve for a battery cell. As the cell ages, Figure 5 The overall shape of the OCV calibration curve will not change, but the high SOC region will gradually shift to the left. The method in this application takes into account the problem of power loss caused by cell aging and is applicable to cell OCV-SOC calibration throughout its entire life cycle.

[0070] 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:

[0071] The cell voltage acquisition accuracy of the battery management system is set according to the measurement error ΔV, and the SOC corresponding to (OCV-ΔV) is obtained by looking up the table. curve_L and the SOC corresponding to (OCV+ΔV) curve_H ;

[0072] When the relationship shown in equation (4) is satisfied, the SOC calibration result obtained from this OCV-SOC calibration is deemed reliable.

[0073] SOC curve_H -SOC curve_L <ΔSOC TH (4)

[0074] Wherein, ΔSOC TH The allowable deviation for OCV-SOC calibration.

[0075] If equation (4) is not satisfied, the SOC calibration result obtained from this calibration is determined to have a large error and is unreliable, and the calibration result is discarded.

[0076] In a preferred embodiment, after completing one OCV-SOC calibration, the next waiting period begins. When the resting time condition is met again, the next OCV-SOC calibration is performed. Meanwhile, when the first calibration after resting is a mid-term charge / discharge OCV calibration, the mid-term charge / discharge OCV calibration is set to invalid after the first calibration to avoid repeatedly entering the mid-term charge / discharge OCV calibration under long-term resting conditions.

[0077] In reality, energy storage systems have short rest periods during operation, and normally only one mid-term OCV calibration is triggered. When the energy storage system fails and shuts down or is shut down for maintenance, it will be in a long-term resting state. At this time, periodic long-term OCV calibration will continuously correct the SOC, ensuring that the system has an accurate initial SOC value when it is recharged and discharged.

[0078] In summary, the technical solution of this application accurately matches the corresponding OCV calibration curve by dynamically identifying the effective calibration point conditions, ensuring the effectiveness of OCV-SOC calibration throughout the entire life cycle of the cell by considering the capacity loss caused by cell aging, and increasing the probability of OCV-SOC calibration by considering calibration triggering under different resting times. By comprehensively considering the influence of multiple factors on OCV, the accuracy of OCV-SOC calibration can be improved.

[0079] The following describes embodiments of the electronic device described in this application, which can be used to perform the method embodiments described in this application. For details not disclosed in the embodiments of the electronic device described in this application, please refer to the method embodiments described in this application.

[0080] Figure 6 A block diagram of an electronic device according to an example embodiment of this application is shown.

[0081] Figure 6 The electronic device shown can perform the aforementioned OCV-SOC calibration method for an energy storage system according to an embodiment of this application.

[0082] The following reference Figure 6 To describe an electronic device 600 according to this embodiment of the present application. Figure 6 The electronic device 600 shown is merely an example and should not impose any limitations on the functionality and scope of use of the embodiments of this application.

[0083] like Figure 6 As shown, the electronic device 600 is presented in the form of a general-purpose computing device. The components of the electronic device 600 may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different system components (including storage unit 620 and processing unit 610), a display unit 640, etc.

[0084] The storage unit stores program code, which can be executed by the processing unit 610, causing the processing unit 610 to perform the methods described in this specification according to various exemplary embodiments of this application.

[0085] Storage unit 620 may include a readable medium in the form of a volatile storage unit, such as random access memory (RAM) 6201 and / or cache memory 6202, and may further include a read-only memory (ROM) 6203.

[0086] Storage unit 620 may also include a program / utility 6204 having a set (at least one) program module 6205, such program module 6205 including but not limited to: operating system, one or more application programs, other program modules and program data, each or some combination of these examples may include an implementation of a network environment.

[0087] Bus 630 can represent one or more of several types of bus structures, including a memory cell bus or memory cell controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0088] Electronic device 600 can also communicate with one or more external devices 700 (e.g., keyboard, pointing device, Bluetooth device, etc.), and with one or more devices that enable a user to interact with electronic device 600, and / or with any device that enables electronic device 600 to communicate with one or more other computing devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 650. Furthermore, electronic device 600 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 660. Network adapter 660 can communicate with other modules of electronic device 600 via bus 630. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0089] Through the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. The technical solutions according to the embodiments of this application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, or network device, etc.) to execute the methods described above according to the embodiments of this application.

[0090] Software products may employ any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example,, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections with one or more wires, portable disks, hard disks, 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), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0091] Computer-readable storage media may include data signals propagated in baseband or as part of a carrier wave, carrying readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable storage medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical fiber, RF, etc., or any suitable combination thereof.

[0092] Program code for performing the operations of this application can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0093] Those skilled in the art will understand that the above modules can be distributed in the device as described in the embodiments, or they can be modified accordingly and placed in one or more devices that are unique to this embodiment. The modules in the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0094] Exemplary embodiments of this application have been specifically shown and described above. It should be understood that this application is not limited to the detailed structures, arrangements, or implementation methods described herein; rather, this application is intended to cover various modifications and equivalent arrangements contained within the spirit and scope of the appended claims.

Claims

1. A method for calibrating an energy storage system using OCV-SOC, characterized in that, Obtain the mid-term and long-term OCV calibration curves of the energy storage system; Real-time monitoring of the charging and discharging process, dynamic identification of effective working conditions for mid-term calibration, and selection of the OCV calibration curve; The calibration point OCV is obtained by measuring the cell voltage. The OCV calibration curve is divided into sections, and SOC calibration is performed in combination with the current cell capacity information. Analyze the SOC calibration deviation to determine whether the SOC calibration results are reliable; The methods for obtaining the intermediate-term OCV calibration curve and the long-term OCV calibration curve are as follows: Under temperature T0, the charging OCV curve and discharging OCV curve after resting for t1 are obtained as the intermediate OCV calibration curve. Taking advantage of the symmetry of the charging OCV and discharging OCV under the same resting time, the midline of the two curves is approximated as the long-term OCV calibration curve after resting for t2. Among them, temperature T0 is the stable temperature of the cell under resting conditions, and resting times t1 and t2 are determined according to the actual operating conditions, with t2 set to be more than twice that of t1.

2. The OCV-SOC calibration method for an energy storage system as described in claim 1, characterized in that, The dynamic identification of the effective point of mid-term calibration and the selection of the OCV calibration curve are as follows: First, the initial capacity SOC0 of the current charge / discharge cycle is obtained. During the charge / discharge cycle, the SOC is calculated in real time using the ampere-hour integration method, and the maximum capacity SOC during the process is dynamically updated. max Minimum Capacity SOC min ; When the current state is charging, if the current capacity satisfies the relationship shown in equation (1), the mid-term charging OCV calibration is determined to be valid, and the mid-term charging OCV calibration curve is selected as the calibration curve. When the current state is in discharge, if the current capacity satisfies the relationship shown in equation (2), the mid-term discharge OCV calibration is determined to be valid, and the mid-term discharge OCV calibration curve is selected as the calibration curve. When equation (1) is not satisfied during charging and equation (2) is not satisfied during discharging, the long-term OCV calibration curve is selected as the calibration curve.

3. The OCV-SOC calibration method for an energy storage system as described in claim 2, characterized in that: When the conditions for mid-term charge / discharge OCV calibration are met under static conditions, the system will wait for mid-term charge / discharge OCV calibration to be performed. When the static time reaches t1 and the cell temperature stabilizes at T0, the corresponding mid-term charge / discharge OCV calibration curve will be called for calibration.

4. The OCV-SOC calibration method for an energy storage system as described in claim 2, characterized in that: If the conditions for effective mid-term charge / discharge OCV calibration are not met under static conditions, long-term OCV calibration will be performed. When the static time reaches t2 and the cell temperature stabilizes at T0, the long-term OCV calibration curve will be called for calibration.

5. The OCV-SOC calibration method for an energy storage system as described in claim 1, characterized in that, The step of partitioning the OCV calibration curve and performing SOC calibration in conjunction with the current capacity information of the battery cell is as follows: The OCV calibration curve is partitioned, and the OCV corresponding to a SOC of 80% is defined as the OCV. TH When OCV ≥ OCV TH For high SOC region, OCV <OCV TH This is a low SOC region; Based on the calibration point OCV obtained from the measured cell voltage, the SOC value corresponding to this OCV is obtained by looking up the table. curve Meanwhile, based on the region where the OCV is located, the SOC of the cell at its current capacity is obtained by calibration according to equation (3). Where Q0 is the initial rated capacity of the battery cell, Q a This represents the current capacity of the battery cell.

6. The OCV-SOC calibration method for an energy storage system as described in claim 1, characterized in that, The specific method for analyzing SOC calibration deviation and determining the reliability of SOC calibration results is as follows: The cell voltage acquisition accuracy of the battery management system is set according to the measurement error ΔV, and the SOC corresponding to (OCV-ΔV) is obtained by looking up the table. curve_L and the SOC corresponding to (OCV+ΔV) curve_H ; When the relationship shown in equation (4) is satisfied, the SOC calibration result obtained from this OCV-SOC calibration is deemed reliable. SOC curve_H -SOC curve_L <ΔSOC TH (4) Wherein, ΔSOC TH The allowable deviation for OCV-SOC calibration.

7. The OCV-SOC calibration method for an energy storage system as described in claim 1, characterized in that: After completing one OCV-SOC calibration, the next waiting period begins. When the resting time condition is met again, the next OCV-SOC calibration will be performed. Meanwhile, if the first calibration after resting is a mid-term charge / discharge OCV calibration, the mid-term charge / discharge OCV calibration will be set to invalid after the first calibration.

8. An electronic device, characterized in that, include: processor; A memory, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the method of any one of claims 1-7.

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