State of charge calibration method and device, battery management system and storage medium

Abstract

The invention relates to a state of charge calibration method and device, a battery management system and a storage medium. The method comprises the following steps: determining equivalent cycle times of battery charging and discharging; under the condition that the equivalent cycle number is greater than a preset number threshold, sending a charge state calibration request; and receiving a state-of-charge calibration instruction returned based on the state-of-charge calibration request, and performing state-of-charge calibration processing on the energy storage battery according to the state-of-charge calibration instruction. By adopting the method and the device, the judgment accuracy of the calibration opportunity can be improved, and the accumulated error of the SOC is within an acceptable range.

Description

Technical Field

[0001] This application relates to the technical field of state of charge (SOC) calibration, and particularly to a method and device for SOC calibration, a battery management system, and a storage medium. Background Art

[0002] With the development of new energy technologies, energy storage systems usually have high reliability, can implement complex protection functions and a large number of protection calculations, support multiple communication protocols, and are equipped with rich external interfaces, etc.

[0003] Currently, for SOC calibration of energy storage systems, it is usually determined whether calibration is required by combining the current SOC of the energy storage system and a preset calibration period.

[0004] However, there is still a problem that the calibration timing is inaccurately judged, which easily leads to an excessive cumulative error of SOC. Summary of the Invention

[0005] Based on the above problems, this application provides a method and device for SOC calibration, a battery management system, and a storage medium, which can improve the accuracy of judging the calibration timing and keep the cumulative error of SOC within an acceptable range.

[0006] In a first aspect, this application provides a method for SOC calibration, which includes: determining the equivalent cycle number of battery charge and discharge in the system; sending a SOC calibration request when the equivalent cycle number is greater than a preset number threshold; receiving a SOC calibration instruction returned based on the SOC calibration request, and performing SOC calibration processing on the battery according to the SOC calibration instruction.

[0007] The technical solution provided by the embodiments of this application takes into account the relationship between the SOC error and the battery charge and discharge frequency. Therefore, it can improve the accuracy of judging the calibration timing, thereby controlling the cumulative error of SOC within an acceptable range for users.

[0008] In some embodiments, the method further includes: determining the preset number threshold according to the maximum error range of the SOC and the error value after each equivalent cycle. The technical solution of the embodiments of this application fully considers the influence of the charge and discharge frequency on the SOC, and can accurately determine the preset number threshold, thereby improving the accuracy of judging the calibration timing.

[0009] In some embodiments, performing a state of charge (SOC) calibration process on a battery according to an SOC calibration instruction includes: determining a target calibration strategy corresponding to the SOC calibration instruction; sending a charge / discharge request according to the target calibration strategy, where the charge / discharge request is used to control the charging or discharging of the battery; and performing an SOC calibration process on the battery. In the technical solution of the embodiments of the present application, the battery management system provides multiple calibration strategies, enabling complex SOC calibration without manual calibration and making the calibration more in line with the system state and the actual needs of users.

[0010] In some embodiments, the target calibration strategy includes a full charge calibration strategy. Sending a charge / discharge request according to the target calibration strategy includes: sending a charge request according to the full charge calibration strategy, where the charge request is used to control the battery to charge and reach the full charge condition; and performing an SOC calibration process on the battery, including: calibrating the SOC of the battery to full charge. The technical solution of the embodiments of the present application provides a high-range full charge calibration scheme for users, enabling the system to perform calibration in a high SOC range, being more in line with the actual needs of users, and reducing the problem of conflicts between calibration and system application conditions.

[0011] In some embodiments, the target calibration strategy includes a static calibration strategy. Sending a charge / discharge request according to the target calibration strategy includes: sending a first discharge request according to the static calibration strategy, where the first discharge request is used to control the battery to discharge to a first low-capacity range; and performing an SOC calibration process on the battery, including: after the battery discharges to the first low-capacity range and stands for a first preset duration, obtaining the static open-circuit voltage of the battery; and calibrating the SOC of the battery according to the static open-circuit voltage and a first parameter table, where the first parameter table includes the corresponding relationship between the static open-circuit voltage and the SOC. The technical solution of the embodiments of the present application provides a low-range static calibration scheme for users, enabling the system to perform static calibration in a low SOC range, being more in line with the actual needs of users, and reducing the problem of conflicts between calibration and system application conditions.

[0012] In some embodiments, the target calibration strategy includes a dynamic calibration strategy. Sending a charge / discharge request according to the target calibration strategy includes: sending a second discharge request according to the dynamic calibration strategy, where the second discharge request is used to control the battery to discharge to a second low-capacity range; correspondingly, performing an SOC calibration process on the battery, including: after the battery discharges to the second low-capacity range and stands for a second preset duration, obtaining the dynamic open-circuit voltage of the battery; and calibrating the SOC of the battery according to the dynamic open-circuit voltage and a second parameter table, where the second parameter table includes the corresponding relationship between the dynamic open-circuit voltage and the SOC. The technical solution of the embodiments of the present application provides a low-range dynamic calibration scheme for users, enabling the system to perform dynamic calibration in a low SOC range, being more in line with the actual needs of users, and reducing the problem of conflicts between calibration and system application conditions.

[0013] In some embodiments, the method further includes: after completing the state of charge (SOC) calibration process, clearing the equivalent cycle count and returning to execute the step of determining the equivalent cycle count of the battery charge and discharge. The technical solution of the embodiment of the present application prepares for a new round of SOC calibration to more accurately determine the calibration timing.

[0014] In a second aspect, the present application further provides a state of charge calibration device, which includes:

[0015] A cycle count determination module, configured to determine the equivalent cycle count of the battery charge and discharge;

[0016] A request sending module, configured to send a state of charge calibration request when the equivalent cycle count is greater than a preset cycle count threshold;

[0017] A calibration processing module, configured to receive a state of charge calibration instruction returned based on the state of charge calibration request and perform a state of charge calibration process on the battery according to the state of charge calibration instruction.

[0018] In a third aspect, an embodiment of the present application provides a battery management system, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the method described in the first aspect are implemented.

[0019] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0020] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, the steps of the method described in the first aspect are implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the detailed description of the following alternative embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the alternative embodiments and are not considered to be a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0022] Figure 1 It is a schematic diagram of the application environment of the state of charge calibration method according to an embodiment of the present application;

[0023] Figure 2 It is a flowchart of the state of charge calibration method according to an embodiment of the present application;

[0024] Figure 3 It is a flowchart of the state of charge calibration method according to an embodiment of the present application;

[0025] Figure 4 is a schematic flowchart of a state of charge calibration method according to an embodiment of the present application;

[0026] Figure 5 is a schematic flowchart of a state of charge calibration method according to an embodiment of the present application;

[0027] Figure 6 is a schematic flowchart of a state of charge calibration method according to an embodiment of the present application;

[0028] Figure 7 is a schematic flowchart of a state of charge calibration method according to another embodiment of the present application;

[0029] Figure 8 is a block diagram of the structure of a state of charge calibration device according to an embodiment of the present application;

[0030] Figure 9 is a block diagram of the structure of a state of charge calibration device according to an embodiment of the present application;

[0031] Figure 10 is a block diagram of the structure of a state of charge calibration device according to an embodiment of the present application;

[0032] Figure 11 is an internal structure diagram of a battery management system according to an embodiment of the present application. Detailed Embodiments

[0033] Hereinafter, embodiments of the technical solutions of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and thus are only examples and should not be used to limit the protection scope of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0035] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality" means more than two unless otherwise specifically defined.

[0036] References to "embodiments" in this specification mean that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0038] With the development of new energy technologies, energy storage systems usually have high reliability, can implement complex protection functions and a large number of protection calculations, can support multiple communication protocols, and are provided with rich external interfaces, etc. Currently, for SOC (State Of Charge) calibration of energy storage systems, it is usually determined whether calibration is required by combining the current SOC of the energy storage system and a preset calibration period. However, most energy storage systems are in frequency modulation operating conditions, and most batteries operate in the platform area where the SOC is 30% - 90%. The corresponding relationship between the SOC and voltage in this interval is not obvious, and it is difficult to determine whether the SOC needs to be calibrated by comparing the SOC and the voltage reference value. Moreover, the SOC error of the battery is not only related to the calibration period but also related to the charge and discharge frequency. Simply judging whether the SOC needs to be calibrated based on the calibration period is also inaccurate. That is to say, the traditional method has an inaccurate judgment of the calibration timing, which easily leads to the problem of excessive cumulative error of the SOC.

[0039] In view of the above problems, the embodiments of the present application provide a state of charge calibration scheme. This scheme first determines the equivalent cycle number of battery charge and discharge; when the equivalent cycle number is greater than a preset number threshold, a state of charge calibration request is sent; then, a state of charge calibration instruction returned based on the state of charge calibration request is received, and the battery is subjected to state of charge calibration processing according to the state of charge calibration instruction. The technical solution provided by the embodiments of the present application takes into account the relationship between the SOC error and the battery charge and discharge frequency. Therefore, it can improve the accuracy of the calibration timing judgment, so that the cumulative error of the SOC is controlled within an acceptable range for users.

[0040] The state of charge calibration scheme provided by the embodiments of the present application can be used for Figure 1In the application environment shown. The application environment includes an energy storage system, which includes multiple energy storage batteries 101, multiple battery management systems (Battery Management System, BMS) 102, a system controller 103, and a power controller 104. Among them, the multiple energy storage batteries 101 can form multiple battery clusters connected in parallel. Each battery cluster corresponds to a battery management system 102, and each battery management system 102 can collect battery information of the corresponding battery cluster. The battery information includes but is not limited to battery voltage, battery current, battery temperature, state of charge of the battery, etc. The multiple battery management systems 102 are all connected to the system controller 103, and each battery management system 102 can transmit the collected battery information to the system controller 103 to manage the battery cluster under the control of the system controller 103. The power controller 104 can also be called a power conversion system (Power Conversion System, PCS). The power controller 104 is connected to the multiple battery management systems 102 and can control the charging or discharging of the energy storage battery 101 through the battery management system 102.

[0041] It should be noted that Figure 1 The structure of one of the energy storage systems is shown. In actual applications, the energy storage system can also adopt other structures.

[0042] According to some embodiments of the present application, with reference to Figure 2 , a state of charge calibration method is provided. Taking the battery management system in Figure 1 as an example for illustration, it can include the following steps:

[0043] Step 201, determine the equivalent cycle number of charge and discharge of the energy storage battery in the energy storage system.

[0044] Among them, the equivalent cycle number includes the charge and discharge times of the energy storage battery.

[0045] The battery management system can first obtain the cumulative charge capacity and cumulative discharge capacity of the energy storage battery; then determine the equivalent cycle number of charge and discharge of the energy storage battery according to the cumulative charge capacity and cumulative discharge capacity.

[0046] Among them, the process of obtaining the cumulative charge capacity and cumulative discharge capacity of the energy storage battery can include: obtaining the charge current and discharge current; using the ampere-hour integration method and the charge current to determine the cumulative charge capacity; using the ampere-hour integration method and the discharge current to determine the cumulative charge capacity. It should be noted that the above charge current and discharge current can be obtained in real time or at a preset period.

[0047] The process of determining the equivalent cycle number of charge and discharge of an energy storage battery based on the cumulative charge capacity and the cumulative discharge capacity may include: determining the sum of the cumulative charge capacity and the cumulative discharge capacity; calculating the ratio between the sum of the capacities and a preset capacity, and determining this ratio as the equivalent cycle number; where the preset capacity is 2 times the nominal capacity, that is, the equivalent cycle number = (cumulative charge capacity + cumulative discharge capacity) / (nominal capacity * 2).

[0048] Step 202, when the equivalent cycle number is greater than a preset number threshold, send a state of charge calibration request to the system controller of the energy storage system.

[0049] Among them, the preset number threshold can be determined according to the maximum error acceptable to the user, and it can be preset by the user in the battery management system.

[0050] The error of the state of charge SOC accumulates during each charge and discharge process. After determining the equivalent cycle number, it is judged whether the equivalent cycle number is greater than the preset number threshold. If the equivalent cycle number is greater than the preset number threshold, it indicates that the SOC error accumulated during multiple charge and discharge processes of the energy storage battery has reached the maximum error acceptable to the user, and the battery management system sends a state of charge calibration request to the system controller.

[0051] If the equivalent cycle number is less than or equal to the preset number threshold, it indicates that the SOC error accumulated during multiple charge and discharge processes of the energy storage battery is still within the error range acceptable to the user, then the SOC of the energy storage battery is not calibrated, and the battery management system does not send a state of charge calibration request to the system controller.

[0052] Step 203, receive the state of charge calibration instruction returned by the system controller based on the state of charge calibration request, and perform state of charge calibration processing on the energy storage battery according to the state of charge calibration instruction.

[0053] After the battery management system sends a state of charge calibration request to the system controller, the state of charge calibration processing may not be carried out immediately. In one scenario, the system controller can prompt the user that the state of charge calibration request has been received, and the user judges whether to perform the state of charge calibration processing. If the state of charge calibration processing is to be performed, the user inputs a calibration trigger operation, and the system controller sends a state of charge calibration instruction to the battery management system according to the calibration trigger operation.

[0054] In another scenario, the system controller can determine whether to perform state of charge (SOC) calibration processing based on the actual situation of the energy storage battery. If SOC calibration processing is to be performed, the system controller sends an SOC calibration instruction to the battery management system. For example, if the energy storage battery is in the power supply state, the system controller determines not to perform SOC calibration processing based on the state of the energy storage battery; if the energy storage system is in the idle state, the system controller determines that SOC calibration processing can be performed based on the state of the energy storage battery and sends an SOC calibration instruction to the battery management system.

[0055] The system controller sends an SOC calibration instruction to the battery management system. Correspondingly, the battery management system receives the SOC calibration instruction sent by the system controller. After that, the battery management system performs SOC calibration processing on the energy storage battery according to the SOC calibration instruction to eliminate the SOC error accumulated during multiple charging and discharging processes of the energy storage battery.

[0056] In one implementation, the SOC calibration processing may be to set the state of charge of the energy storage battery to a preset value.

[0057] In the above embodiments, the equivalent cycle number of charge and discharge of the energy storage battery in the energy storage system is determined; when the equivalent cycle number is greater than the preset number threshold, an SOC calibration request is sent to the system controller of the energy storage system; after that, the SOC calibration instruction returned by the system controller based on the SOC calibration request is received, and the energy storage battery is subjected to SOC calibration processing according to the SOC calibration instruction. The technical solution provided by the embodiments of the present application takes into account the relationship between the SOC error and the charge and discharge frequency of the battery. Therefore, the accuracy of judging the calibration timing can be improved, so that the cumulative error of the SOC is controlled within an acceptable range of the user.

[0058] According to some embodiments of the present application, before determining whether the energy storage battery needs to perform SOC calibration, the embodiments of the present application may further include: determining a preset number threshold according to the maximum error range of the state of charge and the error value after each equivalent cycle.

[0059] Among them, the maximum error range of the state of charge can be determined according to the maximum error acceptable to the user.

[0060] Before setting the preset number threshold, multiple cycle tests can be performed on the energy storage battery, and the error value of the SOC is collected after each cycle test; the error value collected this time is accumulated with the error value collected before to obtain an error cumulative amount. The error cumulative amount is compared with the maximum error range. If the error cumulative amount does not exceed the maximum error range, the next cycle test is performed and the error value is collected. If the error cumulative amount exceeds the maximum error range, the cycle number corresponding to this cycle test is determined as the preset number threshold.

[0061] For example, the error value collected in the first cycle test is SOC1, and the error accumulation amount ΔSOC = SOC1. Compare ΔSOC with the maximum error range SOCmax. If ΔSOC does not exceed SOCmax, then the second cycle test is carried out. The error value collected in the second cycle test is SOC2; the error accumulation amount ΔSOC = SOC1 + SOC2. Compare ΔSOC with the maximum error range SOCmax. If ΔSOC does not exceed SOCmax, then the third cycle test is carried out. And so on. The error value collected in the nth cycle test is SOCn, and the error accumulation amount ΔSOC = SOC1 + SOC2 +... + SOCn. If ΔSOC exceeds SOCmax, then n is determined as the preset number threshold.

[0062] In some embodiments, the error value of SOC collected after each cycle test can be the maximum value among the multiple collected error values.

[0063] In the above embodiments, the preset number threshold is determined according to the maximum error range of the state of charge and the error value after each equivalent cycle. The technical solution of the embodiments of the present application fully considers the influence of the charge and discharge frequency on the SOC, and can accurately determine the preset number threshold, thereby improving the judgment accuracy of the calibration timing.

[0064] According to some embodiments of the present application, with reference to Figure 3 , an implementation manner related to the step "performing state of charge calibration processing on the energy storage battery according to the state of charge calibration instruction" in the above embodiments may include the following steps:

[0065] Step 301, determining a target calibration strategy corresponding to the state of charge calibration instruction.

[0066] Among them, the calibration strategy includes charging conditions and charging operations, or discharging conditions and discharging operations.

[0067] A corresponding relationship between the state of charge calibration instruction and the calibration strategy is established in advance. After the battery management system receives the state of charge calibration instruction sent by the system controller, it can determine the target calibration strategy according to the above corresponding relationship.

[0068] For example, the state of charge calibration instruction a corresponds to the calibration strategy A, the state of charge calibration instruction b corresponds to the calibration strategy B, and the state of charge calibration instruction c corresponds to the calibration strategy C. If the battery management system receives the state of charge calibration instruction b, the target calibration strategy is determined as the calibration strategy B according to the above corresponding relationship.

[0069] Understandably, different state of charge calibration instructions correspond to different calibration strategies. Moreover, the same state of charge calibration instruction can also correspond to different calibration strategies. Alternatively, different state of charge calibration instructions can correspond to the same calibration strategy. For example, state of charge calibration instructions a and b both correspond to calibration strategy A, or state of charge calibration instruction a corresponds to calibration strategies A and B. In such cases, the battery management system can first determine multiple candidate calibration strategies based on the correspondence between the state of charge calibration instructions and the calibration strategies, and then determine the target calibration strategy from the multiple candidate calibration strategies according to other conditions, such as the current SOC of the energy storage battery.

[0070] It should be noted that the above embodiments describe one implementation manner of determining the target calibration strategy. In actual applications, other implementation manners can also be adopted according to the situation.

[0071] Step 302: Send a charge and discharge request to the power controller of the energy storage system according to the target calibration strategy.

[0072] Among them, the charge and discharge request is used to instruct the power controller to control the charging or discharging of the energy storage battery. The charge and discharge request includes at least one of the charging voltage, charging current, charging power, discharging voltage, discharging current, and discharging power.

[0073] After determining the target calibration strategy, the battery management system sends a charge and discharge request to the power controller according to the charge and discharge conditions and operations included in the target calibration strategy. The power controller receives the charge and discharge request and then controls the charging or discharging of the energy storage battery.

[0074] For example, if the target calibration strategy includes a charging operation of charging to a first preset capacity at a charging voltage U, the battery management system sends a charging request to the power controller according to this target calibration strategy. After receiving the charging request, the power controller controls the energy storage battery to charge to the first preset capacity with the charging voltage being U. Or, if the target calibration strategy includes a discharging operation of discharging to a second preset capacity at a discharging current I, the battery management system sends a discharging request to the power controller according to this target calibration strategy. After receiving the discharging request, the power controller controls the energy storage battery to discharge to the second preset capacity with the discharging current being I.

[0075] Step 303: Perform state of charge calibration processing on the energy storage battery.

[0076] After the charging or discharging of the energy storage battery ends, the battery management system performs state of charge calibration processing on the energy storage battery. For example, after the energy storage battery is charged to the first preset capacity, the battery management system calibrates the state of charge of the energy storage battery to the first preset capacity. Or, after the energy storage battery is discharged to the second preset capacity, the battery management system calibrates the state of charge of the energy storage battery to the second preset capacity.

[0077] It should be noted that the above description provides an implementation manner of the state of charge calibration process. In actual applications, other implementation manners can also be adopted.

[0078] In the above embodiments, a target calibration strategy corresponding to the state of charge calibration instruction is determined; a charge and discharge request is sent to the power controller of the energy storage system according to the target calibration strategy; and a state of charge calibration process is performed on the energy storage battery. In the technical solution of the embodiments of the present application, the battery management system provides a variety of calibration strategies, and complex SOC calibration can be achieved without manual calibration, and the calibration is more in line with the state of the energy storage system and the actual needs of users.

[0079] According to some embodiments of the present application, the target calibration strategy includes a full charge calibration strategy. Referring to Figure 4 , an implementation manner of "sending a charge and discharge request to the power controller of the energy storage system according to the target calibration strategy and performing a state of charge calibration process on the energy storage battery" in the above embodiments may include the following steps:

[0080] Step 401, send a charging request to the power controller according to the full charge calibration strategy.

[0081] Among them, the charging request is used to instruct the power controller to control the energy storage battery to charge and reach the full charge condition, and the full charge condition includes at least one of the full charge battery voltage and the full charge battery current.

[0082] When it is determined that the target calibration strategy includes the full charge calibration strategy, the battery management system sends a charging request to the power controller. The power controller receives the charging request and controls the energy storage battery to charge until the energy storage battery reaches the full charge condition and ends.

[0083] For example, the full charge battery voltage is u, and the power controller controls the energy storage battery to charge. If the battery voltage reaches u, it is determined that the energy storage battery reaches the full charge condition and the charging ends; or, the full charge battery current is i, and the power controller controls the energy storage battery to charge. If the battery current reaches i, it is determined that the energy storage battery reaches the full charge condition and the charging ends.

[0084] It should be noted that the full charge condition can be set according to the actual situation.

[0085] Step 402, calibrate the state of charge of the energy storage battery to full charge.

[0086] After the energy storage battery finishes charging, the battery management system calibrates the state of charge of the energy storage battery to full charge, that is, sets the state of charge of the energy storage battery to 100%.

[0087] In the above embodiments, a charging request is sent to the power controller according to the full charge calibration strategy; the state of charge of the energy storage battery is calibrated to full charge. The technical solution of the embodiments of the present application provides a high-range full charge calibration solution for users, which can calibrate the energy storage system in a high SOC range, better meet the actual needs of users, and reduce the problem of conflict between calibration and the application conditions of the energy storage system.

[0088] According to some embodiments of the present application, the target calibration strategy includes a static calibration strategy. Referring to Figure 5 one implementation manner of "sending a charge and discharge request to the power controller of the energy storage system according to the target calibration strategy to perform state of charge calibration processing on the energy storage battery" in the above embodiments may include the following steps:

[0089] Step 501, send a first discharge request to the power controller according to the static calibration strategy.

[0090] The first discharge request is used to instruct the power controller to control the energy storage battery to discharge to a first low-capacity range.

[0091] When it is determined that the target calibration strategy includes the static calibration strategy, the battery management system sends a first discharge request to the power controller. The power controller receives the first discharge request and controls the energy storage battery to discharge until the energy storage battery discharges to the first low-capacity range and ends the discharge.

[0092] Step 502, after the energy storage battery discharges to the first low-capacity range and stands for a first preset duration, obtain the static open-circuit voltage of the energy storage battery.

[0093] The open circuit voltage (OCV) refers to the terminal voltage of the energy storage battery in the open circuit state.

[0094] After the energy storage battery discharges to the first low-capacity range, the energy storage battery is left standing, and the battery management system starts timing. When the timing reaches the first preset duration, the battery management system obtains the static open-circuit voltage of the energy storage battery.

[0095] Step 503, calibrate the state of charge of the energy storage battery according to the static open-circuit voltage and the first parameter table.

[0096] The first parameter table includes the corresponding relationship between the static open-circuit voltage and the state of charge.

[0097] After obtaining the static open-circuit voltage of the energy storage battery, find the state of charge corresponding to the static open-circuit voltage in the first parameter table, and calibrate the state of charge of the energy storage battery to the found state of charge.

[0098] For example, the static open circuit voltage OCV1 of the energy storage battery is obtained, and the state of charge corresponding to the static open circuit voltage OCV1 is found to be SOCa in the first parameter table, then the state of charge of the energy storage battery is set to SOCa; the state of charge corresponding to the static open circuit voltage OCV1 is found to be SOCb in the first parameter table, then the state of charge of the energy storage battery is set to SOCb.

[0099] In the above embodiment, a first discharge request is sent to the power controller according to the static calibration strategy; after the energy storage battery is discharged to the first low capacity interval and is left to stand for a first preset time, the static open circuit voltage of the energy storage battery is obtained; and the state of charge of the energy storage battery is calibrated according to the static open circuit voltage and the first parameter table. The technical solution of the embodiment of the present application provides users with a low-interval static calibration solution, which can enable the energy storage system to be statically calibrated in the low SOC interval, which is more in line with the actual needs of users and reduces the problem of conflict between calibration and the application conditions of the energy storage system.

[0100] According to some embodiments of the present application, the target calibration strategy includes a dynamic calibration strategy, referring to Figure 6 In the above embodiment, an implementation method of "sending a charge and discharge request to a power controller of the energy storage system according to a target calibration strategy to perform a state of charge calibration process on the energy storage battery" may include the following steps:

[0101] Step 601: Send a second discharge request to a power controller according to a dynamic calibration strategy.

[0102] The second discharge request is used to instruct the power controller to control the energy storage battery to discharge to a second low capacity interval.

[0103] When it is determined that the target calibration strategy includes a dynamic calibration strategy, the battery management system sends a second discharge request to the power controller. The power controller receives the second discharge request and controls the energy storage battery to discharge until the energy storage battery discharges to the second low capacity interval and ends the discharge.

[0104] It should be noted that the first low capacity interval used in the static calibration and the second low capacity interval used in the dynamic calibration may be the same or different.

[0105] Step 602: After the energy storage battery is discharged to a second low capacity interval and remains stationary for a second preset time period, a dynamic open circuit voltage of the energy storage battery is obtained.

[0106] After the energy storage battery is discharged to the second low capacity interval, the energy storage battery is left to stand, and the battery management system starts timing. After the timing reaches the second preset time, the battery management system obtains the dynamic open circuit voltage of the energy storage battery.

[0107] It should be noted that the first preset time length used in the static calibration and the second preset time length used in the dynamic calibration may be the same or different.

[0108] Step 603: calibrate the state of charge of the energy storage battery according to the dynamic open circuit voltage and the second parameter table.

[0109] The second parameter table includes the correspondence between the dynamic open circuit voltage and the state of charge. It should be noted that the first parameter table used in the static calibration and the second parameter table used in the dynamic calibration may be the same or different.

[0110] After the dynamic open circuit voltage of the energy storage battery is obtained, the state of charge corresponding to the dynamic open circuit voltage is searched in the second parameter table, and the state of charge of the energy storage battery is calibrated to the searched state of charge.

[0111] For example, the dynamic open circuit voltage OCV2 of the energy storage battery is obtained, and the state of charge corresponding to the dynamic open circuit voltage OCV2 is found to be SOCc in the second parameter table, then the state of charge of the energy storage battery is set to SOCc; the state of charge corresponding to the static open circuit voltage OCV2 is found to be SOCd in the second parameter table, then the state of charge of the energy storage battery is set to SOCd.

[0112] In the above embodiment, a second discharge request is sent to the power controller according to the dynamic calibration strategy; after the energy storage battery is discharged to the second low capacity interval and left to stand for a second preset time, the dynamic open circuit voltage of the energy storage battery is obtained; and the state of charge of the energy storage battery is calibrated according to the dynamic open circuit voltage and the second parameter table. The technical solution of the embodiment of the present application provides users with a low-interval dynamic calibration solution, which can enable the energy storage system to be dynamically calibrated in the low SOC interval, which is more in line with the actual needs of users and reduces the problem of conflict between calibration and the application conditions of the energy storage system.

[0113] According to some embodiments of the present application, the method may further include: after completing the state of charge calibration process, clearing the equivalent cycle number, and returning to execute the step of determining the equivalent cycle number of charging and discharging of the energy storage system.

[0114] After completing the state of charge calibration process, the battery management system clears the equivalent cycle number, and clears the cumulative charging capacity and cumulative discharging capacity calculated in the process of obtaining the equivalent cycle number. At the same time, the signal of the state of charge calibration request can also be cleared.

[0115] After the zeroing process, the process returns to the step of determining the equivalent number of charge and discharge cycles of the energy storage system, that is, a new round of capacity accumulation and state of charge calibration begins.

[0116] In the above embodiments, after completing the state of charge calibration process, the equivalent cycle count is cleared, and the step of determining the equivalent cycle count of the charge and discharge of the energy storage system is returned for execution. The technical solution of the embodiment of the present application prepares for a new round of SOC calibration to more accurately determine the calibration timing.

[0117] According to some embodiments of the present application, referring to Figure 7 , a state of charge calibration method is provided. Taking the case where this method is applied to the Figure 1 battery management system as an example for illustration, it may include the following steps:

[0118] Step 701, obtain the cumulative charge capacity and cumulative discharge capacity of the energy storage battery.

[0119] Step 702, determine the equivalent cycle count of the charge and discharge of the energy storage battery according to the cumulative charge capacity and cumulative discharge capacity.

[0120] Step 703, when the equivalent cycle count is greater than a preset number threshold, send a state of charge calibration request to the system controller.

[0121] Step 704, receive the state of charge calibration instruction returned by the system controller based on the state of charge calibration request.

[0122] Step 705, determine the target calibration strategy corresponding to the state of charge calibration instruction.

[0123] When the target calibration strategy includes a full charge calibration strategy, steps 706 - 707 are executed; when the target calibration strategy includes a static calibration strategy, steps 708 - 710 are executed; when the target calibration strategy includes a dynamic calibration strategy, steps 711 - 713 are executed.

[0124] Step 706, send a charge request to the power controller according to the full charge calibration strategy.

[0125] Among them, the charge request is used to instruct the power controller to control the energy storage battery to charge and reach the full charge condition.

[0126] Step 707, calibrate the state of charge of the energy storage battery to full charge.

[0127] Step 708, send a first discharge request to the power controller according to the static calibration strategy.

[0128] Among them, the first discharge request is used to instruct the power controller to control the energy storage battery to discharge to the first low capacity interval.

[0129] Step 709, after the energy storage battery discharges to the first low capacity interval and stands for the first preset duration, obtain the static open circuit voltage of the energy storage battery.

[0130] Step 710, calibrate the state of charge of the energy storage battery according to the static open-circuit voltage and the first parameter table.

[0131] Wherein, the first parameter table includes the corresponding relationship between the static open-circuit voltage and the state of charge.

[0132] Step 711, send a second discharge request to the power controller according to the dynamic calibration strategy.

[0133] Wherein, the second discharge request is used to instruct the power controller to control the energy storage battery to discharge to the second low-capacity interval;

[0134] Step 712, after the energy storage battery discharges to the second low-capacity interval and stands for the second preset duration, obtain the dynamic open-circuit voltage of the energy storage battery.

[0135] Step 713, calibrate the state of charge of the energy storage battery according to the dynamic open-circuit voltage and the second parameter table.

[0136] Wherein, the second parameter table includes the corresponding relationship between the dynamic open-circuit voltage and the state of charge.

[0137] Step 714, after completing the state of charge calibration process, clear the equivalent cycle count, and return to execute Step 701.

[0138] In the above embodiments, by calculating the equivalent cycle count, the judgment accuracy of the calibration timing can be improved, so that the SOC error accumulation is within the acceptable range of users. Moreover, in the embodiments of the present application, the calibration is guided by the battery management system, and high-precision calibration can be achieved without manual operation. Further, a variety of calibration strategies are provided for users, which can make the calibration more in line with the state of the energy storage system and the actual situation of users.

[0139] It should be understood that although the steps in the above flowchart are displayed in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the above flowchart may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least a part of other steps or steps or stages in other steps.

[0140] Based on the same inventive concept, an embodiment of the present application further provides an overcharge state calibration device for implementing the overcharge state calibration method involved above. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the overcharge state calibration device provided below can refer to the limitations on the overcharge state calibration method in the above text, and will not be repeated here.

[0141] According to some embodiments of the present application, referring to Figure 8 , a state of charge calibration device is provided, and the device includes:

[0142] A cycle number determination module 801, configured to determine the equivalent cycle number of battery charge and discharge;

[0143] A request sending module 802, configured to send a state of charge calibration request when the equivalent cycle number is greater than a preset cycle number threshold;

[0144] A calibration processing module 803, configured to receive a state of charge calibration instruction returned based on the state of charge calibration request, and perform state of charge calibration processing on the battery according to the state of charge calibration instruction.

[0145] In some embodiments, referring to Figure 9 , the device further includes:

[0146] A threshold determination module 804, configured to determine a preset cycle number threshold according to the maximum error range of the state of charge and the error value after each equivalent cycle.

[0147] In some embodiments, the calibration processing module 803 is specifically configured to determine a target calibration strategy corresponding to the state of charge calibration instruction; send a charge and discharge request according to the target calibration strategy, where the charge and discharge request is used to control battery charging or discharging; perform state of charge calibration processing on the battery.

[0148] In some embodiments, the target calibration strategy includes a full charge calibration strategy. The calibration processing module 803 is specifically configured to send a charging request according to the full charge calibration strategy, where the charging request is used to control the battery to charge and reach the full charge condition; calibrate the state of charge of the battery to full charge.

[0149] In some embodiments, the target calibration strategy includes a static calibration strategy. The calibration processing module 803 is specifically configured to send a first discharge request according to the static calibration strategy, where the first discharge request is used to control the battery to discharge to a first low-capacity interval; after the battery discharges to the first low-capacity interval and stands for a first preset duration, obtain the static open-circuit voltage of the battery; calibrate the state of charge of the battery according to the static open-circuit voltage and a first parameter table, where the first parameter table includes the correspondence between the static open-circuit voltage and the state of charge.

[0150] In some embodiments, the target calibration strategy includes a dynamic calibration strategy. The calibration processing module 803 is specifically configured to send a second discharge request according to the dynamic calibration strategy. The second discharge request is used to control the battery to discharge to a second low-capacity range. After the battery discharges to the second low-capacity range and stands for a second preset duration, the dynamic open-circuit voltage of the battery is obtained. The state of charge of the battery is calibrated according to the dynamic open-circuit voltage and a second parameter table, where the second parameter table includes the correspondence between the dynamic open-circuit voltage and the state of charge.

[0151] In some embodiments, with reference to Figure 10 , the device further includes:

[0152] A clearing module 805, configured to clear the equivalent cycle number after completing the state of charge calibration process, and return to execute the step of determining the equivalent cycle number of the battery charge and discharge.

[0153] Each module in the above state of overcharge calibration device can be implemented in whole or in part by software, hardware, and their combination. Each of the above modules can be embedded in the processor of the electronic device in hardware form or be independent of it, or can be stored in the memory of the electronic device in software form, so that the processor can call and execute the operations corresponding to each of the above modules.

[0154] According to some embodiments of the present application, a battery management system is provided. The battery management system can be a terminal, and its internal structure diagram can be as Figure 11 shown. The battery management system includes a processor, a memory, an input / output interface, and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface, the display unit, and the input device are connected to the system bus through the input / output interface. Among them, the processor of the battery management system is used to provide computing and control capabilities. The memory of the battery management system includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the battery management system is used for the processor to exchange information with external devices. The communication interface of the battery management system is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, a state of charge calibration method is implemented.

[0155] Those skilled in the art can understand, Figure 11The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the battery management system to which the solution of this application is applied. Specifically, the battery management system may include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0156] According to some embodiments of the present application, there is also provided a non-transitory computer-readable storage medium including instructions, such as a memory including instructions, and the above instructions can be executed by a processor of an electronic device to complete the above method. For example, the non-transitory computer-readable storage medium may be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device, etc.

[0157] According to some embodiments of the present application, there is also provided a computer program product. When the computer program is executed by a processor, the above method can be implemented. The computer program product includes one or more computer instructions. When these computer instructions are loaded and executed on a computer, part or all of the above method can be implemented in accordance with the process or function described in the embodiments of the present application.

[0158] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0159] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0160] The above-described embodiments merely represent several implementation manners of the present application, facilitating a specific and detailed understanding of the technical solution of the present application, but should not be construed as a limitation on the protection scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all fall within the protection scope of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the technical solution provided by the present application are all within the protection scope of the appended claims of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the content of the appended claims, and the description and the drawings can be used to explain the content of the claims.

Claims

1. A state of charge calibration method, characterized in that, The method includes: Determining the equivalent cycle number of battery charge and discharge; Sending a state of charge calibration request when the equivalent cycle number is greater than a preset number threshold; Receiving a state of charge calibration instruction returned based on the state of charge calibration request, and performing a state of charge calibration process on the battery according to the state of charge calibration instruction.

2. The method according to claim 1, wherein The method further includes: Determining the preset number threshold according to the maximum error range of the state of charge and the error value after each equivalent cycle.

3. The method according to claim 1, characterized in that The performing a state of charge calibration process on the battery according to the state of charge calibration instruction includes: Determining a target calibration strategy corresponding to the state of charge calibration instruction; Sending a charge and discharge request according to the target calibration strategy, where the charge and discharge request is used to control the battery to charge or discharge; Performing a state of charge calibration process on the battery.

4. The method according to claim 3, wherein The target calibration strategy includes a full charge calibration strategy, and the sending a charge and discharge request according to the target calibration strategy includes: Sending a charge request according to the full charge calibration strategy, where the charge request is used to control the battery to charge and reach the full charge condition; The performing a state of charge calibration process on the battery includes: Calibrating the state of charge of the battery to full charge.

5. The method according to claim 3, characterized in that, The target calibration strategy includes a static calibration strategy, and the sending a charge and discharge request according to the target calibration strategy includes: Sending a first discharge request according to the static calibration strategy, where the first discharge request is used to control the battery to discharge to a first low capacity range; The performing a state of charge calibration process on the battery includes: After the battery discharges to the first low capacity range and stands for a first preset duration, obtaining the static open circuit voltage of the battery; Calibrating the state of charge of the battery according to the static open circuit voltage and a first parameter table, where the first parameter table includes the correspondence between the static open circuit voltage and the state of charge.

6. The method according to claim 3, characterized in that, The target calibration strategy includes a dynamic calibration strategy, and the sending a charge and discharge request according to the target calibration strategy includes: Sending a second discharge request according to the dynamic calibration strategy, where the second discharge request is used to control the battery to discharge to a second low capacity range; The performing a state of charge calibration process on the battery includes: After the battery discharges to the second low capacity range and stands for a second preset duration, obtaining the dynamic open circuit voltage of the battery; Calibrating the state of charge of the battery according to the dynamic open circuit voltage and a second parameter table, where the second parameter table includes the correspondence between the dynamic open circuit voltage and the state of charge.

7. The method according to any one of claims 1-6, characterized in that, The method further includes: After completing the state of charge calibration process, clearing the equivalent cycle number and returning to execute the step of determining the equivalent cycle number of battery charge and discharge.

8. A state of charge calibration device, characterized in that, The device includes: A number determination module for determining the equivalent cycle number of battery charge and discharge; A request sending module for sending a state of charge calibration request when the equivalent cycle number is greater than a preset number threshold; A calibration processing module for receiving a state of charge calibration instruction returned based on the state of charge calibration request, and performing a state of charge calibration process on the battery according to the state of charge calibration instruction.

9. A battery management system, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method described in any one of claims 1 to 7.

11. A computer program product comprising a computer program, characterized in that, When this computer program is executed by the processor, it implements the steps of the method described in any one of claims 1 to 7.

Images