Method and device for determining state of charge, charging method and system

Abstract

The application discloses a state of charge determination method and device, a charging method and system, and relates to the technical field of batteries. The state of charge determination method comprises the following steps: in the case that a preset correction condition corresponding to a target voltage type is met, determining a target sub-correction SOC of an energy storage battery according to the target voltage type, a target working state, a current temperature of a battery management system and a current single battery voltage; determining a target total SOC correction accuracy of the energy storage battery according to the target voltage type and the target sub-correction SOC; and in the case that the target total SOC correction accuracy is greater than a current SOC accuracy, determining a target SOC according to the target total SOC correction accuracy, the current SOC and the target sub-correction SOC. According to the embodiment of the application, the accuracy of SOC determination of the energy storage battery can be improved.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a method and apparatus for determining the state of charge, and a charging method and system. Background Technology

[0002] The State of Charge (SOC) of an energy storage battery is a measure of its remaining capacity. Specifically, SOC reflects the percentage of chargeable and dischargeable capacity of a lithium iron phosphate battery during use and is a crucial parameter in the Battery Management System (BMS). An accurate SOC allows for full utilization of the battery's power potential, improves its safety, prevents overcharging or over-discharging, and extends battery life.

[0003] In existing technologies, the State of Charge (SOC) is typically determined through the following steps: 1) Using the capacity of a new single cell as the capacity of the entire energy storage battery; 2) Obtaining an initial SOC value; 3) Integrating the energy storage battery current using ampere-hour (Ah) integration; 4) Correcting the initial SOC value to 100% when the battery is fully charged, or correcting it to 0% when the battery is fully discharged. After correction, repeat step 3) to perform ampere-hour integration calculation to determine the SOC.

[0004] However, in practical applications, energy storage batteries rarely reach full charge and full discharge conditions. Therefore, the above method leads to an increasing accumulation of errors in SOC, resulting in poor accuracy of SOC. Summary of the Invention

[0005] The technical problem to be solved by this application is to address the above-mentioned deficiencies in the prior art by providing a method and apparatus for determining the state of charge, a charging method and system. Using this method for determining the state of charge can increase the number of times the current SOC is corrected, thereby improving the accuracy of the target SOC.

[0006] In a first aspect, embodiments of this application provide a method for determining the state of charge (SOC), applied to energy storage batteries, the method comprising:

[0007] With the battery management system powered on, the target voltage type, target operating state, current SOC, and current SOC accuracy of the energy storage battery are obtained. The target voltage type includes one of the target static voltage, target zero current dynamic voltage, and target non-zero current dynamic voltage. The target operating state includes one of the charging state and the discharging state. The current SOC accuracy is used to characterize the total error of the current SOC of the energy storage battery.

[0008] Under the condition that the preset correction conditions corresponding to the target voltage type are met, the target sub-corrected SOC of the energy storage battery is determined according to the target voltage type, target operating state, current temperature of the battery management system and current single cell voltage.

[0009] Based on the target voltage type and the target sub-corrected SOC, the target total SOC correction accuracy of the energy storage battery is determined; the target total SOC correction accuracy is used to characterize the total error of the target SOC of the energy storage battery.

[0010] If the total SOC correction accuracy is greater than the current SOC accuracy, the target SOC is determined based on the total SOC correction accuracy, the current SOC, and the target sub-correction SOC.

[0011] In some embodiments of the first aspect, obtaining the target voltage type of the energy storage battery specifically includes: obtaining the sleep duration of the battery management system and the current current of the energy storage battery; determining the target voltage type of the energy storage battery as a target static voltage when the sleep duration is greater than or equal to a first preset duration, or when the current current is less than a first value and the first duration is greater than or equal to a second preset duration; the first value is the minimum value between a first product and a first preset current, the first product being the product of a preset percentage and the current ratio of the energy storage battery, and the first duration being the duration during which the current current is less than the first value; determining the target voltage type of the energy storage battery as a target zero-current dynamic voltage when the current current is less than the first value and the first duration is less than the second preset duration; and determining the target voltage type of the energy storage battery as a target non-zero current dynamic voltage when the current current is greater than or equal to the first value.

[0012] In some embodiments of the first aspect, the preset correction conditions corresponding to the target static voltage include:

[0013] The current single-cell voltage of the energy storage battery is in the non-plateau region, and the current SOC accuracy is less than or equal to the first accuracy threshold; the non-plateau region is the interval in the SOC-open circuit voltage OCV curve corresponding to the energy storage battery where the slope is greater than the preset slope.

[0014] The preset correction conditions corresponding to the target zero-current dynamic voltage include:

[0015] The current single-cell voltage of the energy storage battery is in the non-plateau region, and the current SOC accuracy is less than or equal to the second accuracy threshold.

[0016] The preset correction conditions corresponding to the target non-zero current dynamic voltage include:

[0017] The current SOC accuracy is less than or equal to the third accuracy threshold, and the absolute value of the fluctuation of the current current of the energy storage battery is less than or equal to the second preset current, and the second duration is greater than or equal to the third preset duration. The second duration is the duration during which the absolute value of the fluctuation is less than or equal to the second preset current.

[0018] The first accuracy threshold is greater than the second accuracy threshold, and the second accuracy threshold is greater than the third accuracy threshold.

[0019] In some embodiments of the first aspect, the target sub-corrected SOC of the energy storage battery is determined based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage, specifically including:

[0020] When the target voltage type is the target static voltage, the static OCV-SOC mapping relationship is obtained. The static OCV-SOC mapping relationship includes the discharge static OCV-SOC mapping relationship and the charging static OCV-SOC mapping relationship. The discharge static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the discharge state for the target static voltage. The charging static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the charging state for the target static voltage. There is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0021] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the charging static OCV-SOC mapping relationship is determined as the target sub-corrected SOC;

[0022] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the discharge static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0023] In some embodiments of the first aspect, the target sub-corrected SOC of the energy storage battery is determined based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage, specifically including:

[0024] When the target voltage type is the target zero-current dynamic voltage, the current SOC, battery polarization degradation parameter mapping relationship, static OCV-SOC mapping relationship, and first duration are obtained. The first duration is the duration during which the current current of the energy storage battery is less than a first value. The first value is the minimum value between a first product and a first preset current. The first product is the product of a preset percentage and the current ratio of the energy storage battery. The battery polarization degradation parameter mapping relationship includes the battery polarization degradation parameter charging mapping relationship and the battery polarization degradation parameter discharging mapping relationship. The battery polarization degradation parameter charging mapping relationship includes the mapping relationship between multiple durations, multiple SOCs, and multiple OCV conversion coefficients under charging conditions. The battery polarization degradation parameter discharging mapping relationship includes the mapping relationship between multiple durations, multiple SOCs, and multiple OCV conversion coefficients under discharging conditions. The mapping relationships between multiple durations, multiple SOCs, and multiple OCV conversion coefficients; there is a one-to-one correspondence between duration and SOC, and a one-to-one correspondence between SOC and OCV conversion coefficient; the static OCV-SOC mapping relationship includes the discharge static OCV-SOC mapping relationship and the charging static OCV-SOC mapping relationship; the discharge static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the discharge state for the target static voltage; the charging static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the charging state for the target static voltage; there is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0025] When the target operating state is the charging state, the OCV conversion coefficient corresponding to both the current SOC and the first duration in the battery polarization decay parameter charging mapping relationship is determined as the target OCV conversion coefficient.

[0026] The ratio of the current unit voltage to the target OCV conversion factor is determined as the converted unit voltage;

[0027] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the converted single-cell voltage in the charging static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0028] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the converted cell voltage in the discharge static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0029] In some embodiments of the first aspect, the target sub-corrected SOC of the energy storage battery is determined based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage, specifically including:

[0030] When the target voltage type is a target non-zero current dynamic voltage, the non-zero current dynamic voltage mapping relationship is obtained. The non-zero current dynamic voltage mapping relationship includes the charging non-zero current dynamic voltage mapping relationship and the discharging non-zero current dynamic voltage mapping relationship. The charging non-zero current dynamic voltage mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the charging state for the target non-zero current dynamic voltage. The discharging non-zero current dynamic voltage mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the discharging state for the target non-zero current dynamic voltage. There is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0031] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the current single-cell voltage in the charging non-zero current dynamic voltage mapping relationship is determined as the target sub-corrected SOC.

[0032] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the dynamic voltage mapping relationship of the non-zero discharge current is determined as the target sub-corrected SOC.

[0033] In some embodiments of the first aspect, the target total SOC correction accuracy of the energy storage battery is determined based on the target voltage type and the target sub-corrected SOC, specifically including:

[0034] When the target voltage type is either the target static voltage or the target zero-current dynamic voltage, the mapping relationship between the target resting time and the static OCV-SOC accuracy is obtained. The target resting time includes the sleep time of the battery management system and one of the first durations, where the first duration is the duration during which the current current of the energy storage battery is less than a first value. The first value is the minimum value between the first product and the first preset current, where the first product is the product of the preset percentage and the current ratio of the energy storage battery. The static OCV-SOC accuracy mapping relationship includes the correspondence between multiple resting times, multiple sub-corrected SOCs and multiple accuracies, with a one-to-one correspondence between resting time and sub-corrected SOC, and a one-to-one correspondence between sub-corrected SOC and accuracy.

[0035] In the static OCV-SOC accuracy mapping relationship, the accuracy corresponding to both the target static time and the target sub-corrected SOC is determined as the target total SOC correction accuracy.

[0036] In some embodiments of the first aspect, the target total SOC correction accuracy of the energy storage battery is determined based on the target voltage type and the target sub-corrected SOC, specifically including:

[0037] When the target voltage type is a target non-zero current dynamic voltage, the non-zero current dynamic voltage SOC accuracy mapping relationship and the current current of the energy storage battery are obtained. The non-zero current dynamic voltage SOC accuracy mapping relationship includes the charging non-zero current dynamic voltage SOC accuracy mapping relationship and the discharging non-zero current dynamic voltage SOC accuracy mapping relationship. The charging non-zero current dynamic voltage SOC accuracy mapping relationship includes the mapping relationship between multiple currents, multiple sub-corrected SOCs, and multiple accuracies under the charging state. The discharging non-zero current dynamic voltage SOC accuracy mapping relationship includes the mapping relationship between multiple currents, multiple sub-corrected SOCs, and multiple accuracies under the discharging state. There is a one-to-one correspondence between current and sub-corrected SOC, and a one-to-one correspondence between sub-corrected SOC and accuracy.

[0038] When the target operating state is the charging state, the accuracy corresponding to both the current current and the target sub-corrected SOC in the dynamic voltage SOC accuracy mapping relationship of the non-zero charging current is determined as the target total SOC correction accuracy.

[0039] When the target operating state is the discharge state, the accuracy corresponding to both the current current and the target sub-corrected SOC in the dynamic voltage SOC accuracy mapping relationship of the non-zero discharge current is determined as the target total SOC correction accuracy.

[0040] In some embodiments of the first aspect, the method further includes:

[0041] Under the condition of satisfying the first preset update, the maximum cell voltages of the energy storage battery corresponding to multiple first reference SOCs are obtained. Under the condition that all maximum cell voltages pass the verification, the dynamic voltage SOC accuracy mapping relationship of charging non-zero current is updated according to all maximum cell voltages.

[0042] The first preset update conditions include: the target total SOC correction accuracy is greater than the fourth accuracy threshold; the consistency difference of the energy storage battery is less than or equal to the consistency threshold; the battery management system is in a charging state; and the average temperature of the battery management system is greater than or equal to the first temperature threshold.

[0043] In some embodiments of the first aspect, the method further includes:

[0044] Under the condition of satisfying the second preset update, the minimum cell voltages of the energy storage battery corresponding to multiple second reference SOCs are obtained. Under the condition that all minimum cell voltages pass the verification, the dynamic voltage SOC accuracy mapping relationship of the discharge non-zero current is updated according to all minimum cell voltages.

[0045] The second preset update conditions include: the target total SOC correction accuracy is greater than the fourth accuracy threshold; the consistency difference of the energy storage battery is less than or equal to the consistency threshold; the battery management system is not in a charging state; and the average temperature of the battery management system is greater than or equal to the second temperature threshold.

[0046] In some implementations of the first aspect, obtaining the current SOC accuracy specifically includes:

[0047] Obtain the initial SOC accuracy and the ampere-hour integration SOC accuracy; the initial SOC accuracy includes one of the historical SOC accuracy and the initial sub-correction SOC accuracy; the ampere-hour integration SOC accuracy is the SOC accuracy obtained through ampere-hour integration;

[0048] The difference between the initial SOC accuracy and the ampere-hour integral SOC accuracy is determined as the current SOC accuracy.

[0049] In some embodiments of the first aspect, the target SOC is determined based on the target total SOC correction accuracy, the current SOC, and the target sub-correction SOC, specifically including: determining the difference between the preset value and the target total SOC correction accuracy as the first accuracy difference;

[0050] The product of the total target SOC correction accuracy and the target sub-correction SOC is determined as the first accuracy product;

[0051] The product of the current SOC and the difference in first precision, and the sum of the products of the current SOC and the first precision, are used to determine the target SOC.

[0052] Based on the same inventive concept, in a second aspect, embodiments of this application also provide a charging method applied to an energy storage battery, the method comprising:

[0053] Determine the target SOC of the energy storage battery according to the method for determining the state of charge (SOC) of any one of the first aspects.

[0054] Based on the target SOC, a charging strategy is determined, which is used to characterize the charging speed of the energy storage battery.

[0055] Implement a charging strategy to charge the energy storage battery.

[0056] Based on the same inventive concept, in a third aspect, embodiments of this application provide a SOC determination device applied to an energy storage battery, the device comprising:

[0057] The first acquisition module is used to acquire the target voltage type, target operating state, current SOC, and current SOC accuracy of the energy storage battery when the battery management system is powered on. The target voltage type includes one of the target static voltage, target zero current dynamic voltage, and target non-zero current dynamic voltage; the target operating state includes one of the charging state and the discharging state; and the current SOC accuracy is used to characterize the total error of the current SOC of the energy storage battery.

[0058] The first determining module, connected to the first acquiring module, is used to determine the target sub-corrected SOC of the energy storage battery based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage, provided that the preset correction conditions corresponding to the target voltage type are met.

[0059] The second determining module, connected to the first determining module, is used to determine the target total SOC correction accuracy of the energy storage battery based on the target voltage type and the target sub-corrected SOC; the target total SOC correction accuracy is used to characterize the total error of the target SOC of the energy storage battery.

[0060] The third determining module, connected to the second determining module, is used to determine the target SOC based on the target total SOC correction accuracy, the current SOC, and the target sub-corrected SOC when the target total SOC correction accuracy is greater than the current SOC accuracy.

[0061] In some embodiments of the third aspect, the first acquisition module is specifically used for:

[0062] Obtain the sleep duration of the battery management system and the current current of the energy storage battery;

[0063] If the sleep duration is greater than or equal to the first preset duration, or if the current current is less than the first value and the first duration is greater than or equal to the second preset duration, the target voltage type of the energy storage battery is determined to be the target static voltage; the first value is the minimum value between the first product and the first preset current, the first product is the product of the preset percentage and the current ratio of the energy storage battery, and the first duration is the duration during which the current current is less than the first value.

[0064] When the current is less than the first value and the first duration is less than the second preset duration, the target voltage type of the energy storage battery is determined to be the target zero current dynamic voltage.

[0065] When the current is greater than or equal to the first value, the target voltage type of the energy storage battery is determined to be the target non-zero current dynamic voltage.

[0066] In some embodiments of the third aspect, the second determining module is specifically used for:

[0067] When the target voltage type is either the target static voltage or the target zero-current dynamic voltage, the mapping relationship between the target resting time and the static OCV-SOC accuracy is obtained. The target resting time includes the sleep time of the battery management system and one of the first durations, where the first duration is the duration during which the current current of the energy storage battery is less than a first value. The first value is the minimum value between the first product and the first preset current, where the first product is the product of the preset percentage and the current ratio of the energy storage battery. The static OCV-SOC accuracy mapping relationship includes the correspondence between multiple resting times, multiple sub-corrected SOCs and multiple accuracies, with a one-to-one correspondence between resting time and sub-corrected SOC, and a one-to-one correspondence between sub-corrected SOC and accuracy.

[0068] In the static OCV-SOC accuracy mapping relationship, the accuracy corresponding to both the target static time and the target sub-corrected SOC is determined as the target total SOC correction accuracy.

[0069] In some embodiments of the third aspect, the second determining module is specifically used for:

[0070] When the target voltage type is a target non-zero current dynamic voltage, the non-zero current dynamic voltage SOC accuracy mapping relationship and the current current of the energy storage battery are obtained. The non-zero current dynamic voltage SOC accuracy mapping relationship includes the charging non-zero current dynamic voltage SOC accuracy mapping relationship and the discharging non-zero current dynamic voltage SOC accuracy mapping relationship. The charging non-zero current dynamic voltage SOC accuracy mapping relationship includes the mapping relationship between multiple currents, multiple sub-corrected SOCs, and multiple accuracies under the charging state. The discharging non-zero current dynamic voltage SOC accuracy mapping relationship includes the mapping relationship between multiple currents, multiple sub-corrected SOCs, and multiple accuracies under the discharging state. There is a one-to-one correspondence between current and sub-corrected SOC, and a one-to-one correspondence between sub-corrected SOC and accuracy.

[0071] When the target operating state is the charging state, the accuracy corresponding to both the current current and the target sub-corrected SOC in the dynamic voltage SOC accuracy mapping relationship of the non-zero charging current is determined as the target total SOC correction accuracy.

[0072] When the target operating state is the discharge state, the accuracy corresponding to both the current current and the target sub-corrected SOC in the dynamic voltage SOC accuracy mapping relationship of the discharge non-zero current is determined as the target total SOC correction accuracy.

[0073] Based on the same inventive concept, in a fourth aspect, embodiments of this application also provide a charging system for use in an energy storage battery, the system comprising:

[0074] Such as the SOC determining device of any of the third aspects, used to determine the target SOC of the energy storage battery;

[0075] The strategy determination device, connected to the SOC determination device, is used to determine the charging strategy based on the target SOC. The charging strategy is used to characterize the charging speed of the energy storage battery.

[0076] An execution device, connected to a strategy determination device, is used to execute a charging strategy to charge the energy storage battery.

[0077] According to the method and apparatus for determining the state of charge, the charging method and system provided in the embodiments of this application, firstly, with the battery management system powered on, the target voltage type, target operating state, current SOC, and current SOC accuracy of the energy storage battery are obtained; then, if the preset correction conditions corresponding to the target voltage type are met, the target sub-corrected SOC of the energy storage battery is determined based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage; then, based on the target voltage type and the target sub-corrected SOC, the target total SOC correction accuracy of the energy storage battery is determined; the target total SOC correction accuracy is used to characterize the total error of the target SOC of the energy storage battery; and then, if the target total SOC correction accuracy is greater than the current SOC accuracy, the target SOC is determined based on the target total SOC correction accuracy, the current SOC, and the target sub-corrected SOC. It is evident that, on the one hand, compared to the prior art where the correction of the current SOC is only triggered when the full charge and full discharge conditions are met, in this embodiment, by dividing the target voltage type of the energy storage battery into target static voltage, target zero current dynamic voltage, and target non-zero current dynamic voltage, the target sub-corrected SOC of the energy storage battery is determined under the preset correction conditions corresponding to the target voltage type. That is, the correction of the current SOC is triggered when the preset correction conditions corresponding to the target voltage type are met, which can increase the number of corrections to the current SOC and thus improve the accuracy of the target SOC. On the other hand, since the accuracy of the target total SOC correction is greater than the accuracy of the current SOC, the target SOC determined based on the accuracy of the target total SOC correction, the current SOC, and the target sub-corrected SOC is more accurate than the current SOC, which can further improve the accuracy of the target SOC.

[0078] Furthermore, by introducing the target total SOC correction accuracy, the target SOC is determined only when the target total SOC correction accuracy is greater than the current SOC accuracy, based on the target total SOC correction accuracy, the current SOC, and the target sub-correction SOC. In other words, the determination of the target SOC is based on the magnitude of the target total SOC correction accuracy. This can improve or solve the problems of miscorrection or omission. In addition, it can reduce the calculation process when the target total SOC correction accuracy is less than or equal to the current SOC accuracy, thereby saving computing resources. Attached Figure Description

[0079] Figure 1 This diagram illustrates a flowchart of a method for determining the state of charge provided in an embodiment of this application.

[0080] Figure 2 This illustration shows a schematic diagram of an OCV-SOC curve provided in an embodiment of this application.

[0081] Figure 3 This diagram illustrates a structural schematic of a SOC determination device provided in an embodiment of this application. Detailed Implementation

[0082] To enable those skilled in the art to better understand the technical solutions of this application, the application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0083] The features and exemplary embodiments of various aspects of this application will now be described in detail. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain this application and are not configured to limit this application. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples of this application.

[0084] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0085] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship. Example 1

[0086] The method for determining the state of charge (SOC) provided in this application embodiment is applicable to application scenarios such as dynamic range prediction, power allocation optimization, and intelligent scheduling of energy storage systems. This SOC determination method can be applied to energy storage batteries, such as lithium iron phosphate batteries. The SOC determination method can be executed by an SOC determination device, electronic equipment, and a battery management system (BMS). The following explanation uses the example of the SOC determination method being executed by an electronic device.

[0087] like Figure 1 As shown, the method for determining the state of charge provided in this application embodiment may include steps S110 to S140.

[0088] S110. When the battery management system is powered on, obtain the target voltage type, target operating state, current SOC, and current SOC accuracy of the energy storage battery. The target voltage type includes one of the target static voltage, target zero current dynamic voltage, and target non-zero current dynamic voltage. The target operating state includes one of the charging state and the discharging state. The current SOC accuracy is used to characterize the total error of the current SOC of the energy storage battery.

[0089] S120. Under the condition that the preset correction conditions corresponding to the target voltage type are met, determine the target sub-corrected SOC of the energy storage battery according to the target voltage type, target operating state, current temperature of the battery management system and current single cell voltage.

[0090] S130. Determine the target total SOC correction accuracy of the energy storage battery based on the target voltage type and the target sub-corrected SOC; the target total SOC correction accuracy is used to characterize the total error of the target SOC of the energy storage battery.

[0091] S140. If the total target SOC correction accuracy is greater than the current SOC accuracy, determine the target SOC based on the total target SOC correction accuracy, the current SOC, and the target sub-correction SOC.

[0092] According to the method for determining the state of charge (SOC) provided in the embodiments of this application, firstly, with the battery management system powered on, the target voltage type, target operating state, current SOC, and current SOC accuracy of the energy storage battery are obtained; then, if the preset correction conditions corresponding to the target voltage type are met, the target sub-corrected SOC of the energy storage battery is determined based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage; then, the target total SOC correction accuracy of the energy storage battery is determined based on the target voltage type and the target sub-corrected SOC; the target total SOC correction accuracy is used to characterize the total error of the target SOC of the energy storage battery; and then, if the target total SOC correction accuracy is greater than the current SOC accuracy, the target SOC is determined based on the target total SOC correction accuracy, the current SOC, and the target sub-corrected SOC. It is evident that, on the one hand, compared to the prior art where the correction of the current SOC is only triggered when the full charge and full discharge conditions are met, in this embodiment, by dividing the target voltage type of the energy storage battery into target static voltage, target zero current dynamic voltage, and target non-zero current dynamic voltage, the target sub-corrected SOC of the energy storage battery is determined under the preset correction conditions corresponding to the target voltage type. That is, the correction of the current SOC is triggered when the preset correction conditions corresponding to the target voltage type are met, which can increase the number of corrections to the current SOC and thus improve the accuracy of the target SOC. On the other hand, since the accuracy of the target total SOC correction is greater than the accuracy of the current SOC, the target SOC determined based on the accuracy of the target total SOC correction, the current SOC, and the target sub-corrected SOC is more accurate than the current SOC, which can further improve the accuracy of the target SOC.

[0093] Furthermore, by introducing the target total SOC correction accuracy, the target SOC is determined only when the target total SOC correction accuracy is greater than the current SOC accuracy, based on the target total SOC correction accuracy, the current SOC, and the target sub-correction SOC. In other words, the determination of the target SOC is based on the magnitude of the target total SOC correction accuracy. This can improve or solve the problems of miscorrection or omission. In addition, it can reduce the calculation process when the target total SOC correction accuracy is less than or equal to the current SOC accuracy, thereby saving computing resources.

[0094] The specific implementation methods for each of the above steps are described below.

[0095] In step S110, the battery management system is powered on, that is, the battery management system is connected to a power source.

[0096] For example, the target static voltage may include a dormant static voltage and a low-current equivalent static voltage. The dormant static voltage may be the voltage when the BMS dormant duration is greater than or equal to a first preset duration; the low-current equivalent static voltage may be the voltage when the current is less than a first value and the first duration is greater than or equal to a second preset duration. Wherein, the first value is the minimum of a first product and a first preset current, the first product is the product of a preset percentage and the current ratio of the energy storage battery, and the first duration is the duration during which the current is less than the first value.

[0097] Optionally, the mapping relationship between the ambient temperature of the energy storage battery and the first preset duration satisfies the following: an ambient temperature of [-40, 10]℃ is mapped to [3, 1]h. For example, the first preset duration corresponding to an ambient temperature of -40℃ is 3h.

[0098] Optionally, the mapping relationship between ambient temperature and the second preset duration satisfies the following: ambient temperature [-40, 10]℃ maps to [3, 1]h. For example, the first preset duration corresponding to an ambient temperature of 10℃ is 1h.

[0099] It should be noted that the first preset duration, second preset duration, preset percentage, energy storage battery capacity, and first preset current can be set according to actual conditions. The first preset duration and second preset duration can be equal or unequal, and no limitation is made here. For example, the first preset duration and second preset duration can both be 15 minutes, the first value can be Min (0.01C1, 5A), that is, the preset percentage is 1%, the current multiplier of the energy storage battery is C1, and the first preset current is 5A.

[0100] Optionally, the target zero-current dynamic voltage can be the voltage when the current is less than a first value and the first duration of the current being less than the first value is less than a second preset duration. For example, the target zero-current dynamic voltage can be the voltage when the current is less than Min (0.01C1, 5A) and the first duration is less than 15 minutes.

[0101] Optionally, the target non-zero current dynamic voltage can be the voltage when the current is greater than or equal to a first value. For example, the target non-zero current dynamic voltage can be the voltage when the current is greater than Min (0.01C1, 5A).

[0102] In some implementations, obtaining the target voltage type of the energy storage battery specifically includes:

[0103] Obtain the sleep duration of the battery management system and the current current of the energy storage battery;

[0104] If the sleep duration is greater than or equal to the first preset duration, or if the current current is less than the first value and the first duration is greater than or equal to the second preset duration, the target voltage type of the energy storage battery is determined to be the target static voltage; the first value is the minimum value between the first product and the first preset current, the first product is the product of the preset percentage and the current ratio of the energy storage battery, and the first duration is the duration during which the current current is less than the first value.

[0105] When the current is less than the first value and the first duration is less than the second preset duration, the target voltage type of the energy storage battery is determined to be the target zero current dynamic voltage.

[0106] When the current is greater than or equal to the first value, the target voltage type of the energy storage battery is determined to be the target non-zero current dynamic voltage.

[0107] Optionally, the target operating state can be determined by obtaining the operating state identifier. For example, if the operating state identifier is 1, the target operating state is determined to be the charging state; if the operating state identifier is 0, the target operating state is determined to be the discharging state.

[0108] Optionally, the current SOC can be determined using an initial SOC algorithm from related technologies. For example, if the dormancy period is greater than or equal to a first preset period, and the current cell voltage of the energy storage battery is in the non-plateau region, the current SOC can be obtained by querying the Open Circuit Voltag (OCV) - SOC table. Specifically, cell testing can be used to obtain an array table of SOC and OCV, and the current SOC can be obtained by detecting the open circuit voltage of the energy storage battery and then using the SOC and OCV array table. For example, if the hibernation period is less than the first preset period, or if the current single-cell voltage of the energy storage battery is not in the non-platform range, and if the SOC value stored in the Electrically Erasable Programmable Read-Only Memory (EEPROM) before the last hibernation is valid, the current SOC can be equal to the SOC value stored in the EEPROM before the last hibernation minus the standby power consumption multiplied by its corresponding weight (weight ≥ 0.1 to enable). When the battery is parked for a long time, the current SOC should be appropriately reduced. The reduction value of the current SOC can be determined based on the actual test value. For example, the reduction value can be 1% per day, or 1% / 1440 per minute. If the SOC value stored in the EEPROM before the last hibernation is invalid, the current SOC can be equal to the default value of 50%.

[0109] In some implementations, obtaining the current SOC accuracy specifically includes:

[0110] Obtain the initial SOC accuracy and the ampere-hour integration SOC accuracy; the initial SOC accuracy includes one of the historical SOC accuracy and the initial sub-correction SOC accuracy; the ampere-hour integration SOC accuracy is the SOC accuracy obtained through ampere-hour integration;

[0111] The difference between the initial SOC accuracy and the ampere-hour integral SOC accuracy is determined as the current SOC accuracy.

[0112] Optionally, the initial SOC accuracy AcuurSOCRect(t0) can satisfy formula (1). Formula (1) includes: AcuurSOCRect(t0) = AcuurSOCRectNvm or AcuurSOCSubRect. Wherein, AcuurSOCRectNvm represents the historical SOC accuracy, that is, the historical stored value; AcuurSOCSubRect represents the sub-correction accuracy of a certain SOC correction algorithm for ampere-hour integration, that is, the target total SOC correction accuracy. Specifically, when the low-voltage circuit is working, the initial SOC accuracy is the historical SOC accuracy; when the SOC correction algorithm is triggered at time t0, the initial SOC accuracy is the target total SOC correction accuracy. Triggering the SOC correction algorithm can be done by executing step S120.

[0113] Optionally, the accuracy of the ampere-hour integral SOC, AcuurSOCRectAh(t), can satisfy formula (2). Formula (2) includes Wherein, the ampere-hour integration SOC accuracy AcuurSOCRectAh(t) represents the SOC accuracy obtained by ampere-hour integration at time t0; CN is the calibrated value of the energy storage battery capacity; and i represents the current.

[0114] Optionally, the current SOC accuracy AcuurSOCRect(t+1) can satisfy formula (3). Formula (3) includes AcuurSOCRect(t+1) = AcuurSOCRect(t0) - AcuurSOCRectAh(t). Wherein, the current SOC accuracy AcuurSOCRect(t+1) is also the SOC accuracy at time t+1.

[0115] In step S120, after acquiring the target voltage type, target operating state, current SOC, and current SOC accuracy of the energy storage battery, the electronic device can also determine the target sub-corrected SOC of the energy storage battery based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage, provided that the preset correction conditions corresponding to the target voltage type are met.

[0116] For example, the target sub-correction SOC can be the sub-correction SOC of the correction algorithm.

[0117] In some implementations, the preset correction conditions corresponding to the target static voltage include:

[0118] The current single-cell voltage of the energy storage battery is in the non-plateau region, and the current SOC accuracy is less than or equal to the first accuracy threshold. The non-plateau region is the interval in the SOC-open circuit voltage (OCV) curve corresponding to the energy storage battery where the slope is greater than the preset slope.

[0119] The preset correction conditions corresponding to the target zero-current dynamic voltage include:

[0120] The current single-cell voltage of the energy storage battery is in the non-plateau region, and the current SOC accuracy is less than or equal to the second accuracy threshold.

[0121] The preset correction conditions corresponding to the target non-zero current dynamic voltage include:

[0122] The current SOC accuracy is less than or equal to the third accuracy threshold, and the absolute value of the fluctuation of the current current of the energy storage battery is less than or equal to the second preset current, and the second duration is greater than or equal to the third preset duration. The second duration is the duration during which the absolute value of the fluctuation is less than or equal to the second preset current.

[0123] The first accuracy threshold is greater than the second accuracy threshold, and the second accuracy threshold is greater than the third accuracy threshold.

[0124] For example, the current cell voltage can be obtained through actual measurement.

[0125] It should be noted that the third preset duration can be set according to actual conditions and is not limited here. The third preset duration can be equal to or different from the first and second preset durations. For example, the third preset duration can be 15 minutes.

[0126] It should be noted that the first, second, and third accuracy thresholds can all be set according to the actual situation, and are not limited here. For example, the first accuracy threshold can be 97%, the second accuracy threshold can be 95%, and the third accuracy threshold can be 92%.

[0127] For example, such as Figure 2As shown, the non-platform region includes the low-segment non-platform region, the mid-segment non-platform region, and the high-segment non-platform region. Specifically, the low-segment non-platform region has a SOC of 0% ≤ SOC ≤ 30%, indicating high reliability and easily met conditions; the mid-segment non-platform region has a SOC of 55% ≤ SOC ≤ 65%, indicating low reliability and easily met medium conditions; and the high-segment non-platform region has a SOC ≥ 96%, indicating medium reliability and easily met low conditions. The plateau region includes the low-segment and high-segment plateau regions; the low-segment plateau region has a SOC of 30% ≤ SOC ≤ 55%; and the high-segment plateau region has a SOC of 65% ≤ SOC ≤ 96%. The plateau region is the area in the SOC-OCV curve where the slope is less than the preset slope. Specifically, 0% corresponds to a single-cell voltage of 2947mV, 30% corresponds to a single-cell voltage of 3283mV, and 96% corresponds to a single-cell voltage of 3341mV.

[0128] For example, the second preset current can be set according to the actual situation, and is not limited here. For example, the second preset current can be 3A.

[0129] For example, when the target voltage type is a target zero-current dynamic voltage and there is zero current, to reduce correction errors, when the first duration for which the current is less than a first value is less than a second preset duration, a limit of more than 5 minutes is set. Subsequently, if the preset correction condition corresponding to the target zero-current dynamic voltage is still met, a correction is triggered every 3 minutes until the preset correction condition corresponding to the target zero-current dynamic voltage is no longer met. That is, when the preset correction condition corresponding to the target zero-current dynamic voltage is triggered for the first time, the second preset duration is 5 minutes; when the preset correction condition corresponding to the target zero-current dynamic voltage is not triggered for the first time, the second preset duration is 3 minutes.

[0130] For example, when the current is non-zero and fluctuates within a certain range, the absolute value of the fluctuation of the current of the energy storage battery is less than or equal to 3A, and the second duration of less than or equal to 3A is greater than or equal to the third preset duration. However, in order to reduce correction errors, a constraint of greater than or equal to 5 minutes is set when the condition is met for the first time. If the preset correction condition corresponding to the target non-zero current dynamic voltage is still met subsequently, a correction is triggered every 3 minutes until the zero current condition is no longer met. That is to say, when the preset correction condition corresponding to the target non-zero current dynamic voltage is triggered for the first time, the third preset duration can be 5 minutes; when the preset correction condition corresponding to the target non-zero current dynamic voltage is not triggered for the first time, the third preset duration can be 3 minutes.

[0131] In some implementations, the target sub-corrected SOC of the energy storage battery is determined based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage. Specifically, this includes:

[0132] When the target voltage type is the target static voltage, the static OCV-SOC mapping relationship is obtained. The static OCV-SOC mapping relationship includes the discharge static OCV-SOC mapping relationship and the charging static OCV-SOC mapping relationship. The discharge static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages and multiple sub-corrected SOCs in the discharge state for the target static voltage. The charging static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages and multiple sub-corrected SOCs in the charging state for the target static voltage. There is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0133] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0134] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the discharge static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0135] For example, all mapping relationships involved in the embodiments of this application can be represented in tabular form.

[0136] For example, the discharge static OCV-SOC mapping relationship provided in the embodiments of this application is shown in Tables 1-1 and 1-2.

[0137] Table 1-1

[0138] Temperature (°C) / Sub-corrected SOC (%) 0 5 10 15 20 25 30 40 50 -40 2693 3134 3203 3223 3245 3262 3269 3270 3271 -20 2693 3134 3203 3223 3245 3262 3269 3270 3271 -10 2693 3134 3203 3223 3245 3262 3269 3270 3271 -5 2693 3134 3203 3223 3245 3262 3269 3270 3271 0 2683 3122 3202 3220 3244 3263 3273 3275 3277 5 2672 3110 3201 3216 3242 3263 3277 3280 3283 10 2697 3118 3202 3217 3243 3263 3280 3286 3288 25 2813 3131 3202 3219 3243 3261 3277 3291 3293 55 2813 3131 3202 3219 3243 3261 3277 3291 3293

[0139] Table 1-2

[0140] Temperature (°C) / Sub-corrected SOC (%) 55 60 65 70 75 80 90 95 98 100 -40 3276 3280 3280 3303 3307 3311 3313 3315 3315 3516 -20 3276 3280 3280 3303 3307 3311 3313 3315 3315 3516 -10 3276 3280 3280 3303 3307 3311 3313 3315 3315 3516 -5 3276 3280 3280 3303 3307 3311 3313 3315 3315 3516 0 3283 3289 3289 3315 3317 3319 3320 3322 3322 3497 5 3290 3297 3297 3327 3327 3327 3327 3328 3328 3478 10 3204 3300 3300 3330 3330 3330 3330 3331 3331 3495 25 3298 3303 3303 3331 3332 3332 3333 3333 3333 3412 55 3298 3303 3303 3331 3332 3332 3333 3333 3333 3412

[0141] It should be noted that Tables 1-1 and 1-2 together constitute an example of a complete static discharge OCV-SOC mapping relationship, and the data in Tables 1-1 and 1-2 are for illustrative purposes only and are not intended to limit this application. For example, in Table 1-1, the SOC corresponding to a temperature of -40℃ and a cell voltage of 2693mV is 0%. Similarly, in Table 1-2, the SOC corresponding to a temperature of -10℃ and a cell voltage of 3276mV is 55%.

[0142] For example, the charging static OCV-SOC mapping relationship provided in the embodiments of this application is shown in Tables 2-1 and 2-2.

[0143] Table 2-1

[0144] Temperature (°C) / Sub-corrected SOC (%) 0 5 10 15 20 25 30 40 50 55 0 2672 3110 3201 3216 3242 3263 3277 3280 3283 3290 5 2697 3118 3202 3217 3243 3263 3280 3286 3288 3294 10 2697 3118 3202 3217 3243 3263 3280 3286 3288 3294 25 2813 3131 3202 3219 3243 3261 3277 3291 3293 3298 45 2816 3134 3205 3222 3246 3264 3280 3294 3296 3301

[0145] Table 2-2

[0146] Temperature (°C) / Sub-corrected SOC (%) 60 65 70 75 80 90 95 98 100 0 3297 3297 3327 3327 3327 3327 3328 3328 3478 5 3300 3300 3330 3330 3330 3330 3331 3331 3495 10 3300 3300 3330 3330 3330 3330 3331 3331 3495 25 3303 3303 3331 3332 3332 3333 3333 3333 3412 45 3306 3306 3334 3334.5 3335 3336 3336 3336 3415

[0147] It should be noted that Tables 2-1 and 2-2 together constitute an example of a complete static charging OCV-SOC mapping relationship, and the data in Tables 2-1 and 2-2 are for illustrative purposes only and are not intended to limit this application. For example, in Table 2-1, the SOC corresponding to a temperature of 0℃ and a single-cell voltage of 3110mV is 5%. Similarly, in Table 2-2, the SOC corresponding to a temperature of 25℃ and a single-cell voltage of 3303mV is 60%.

[0148] In other implementations, the target sub-corrected SOC of the energy storage battery is determined based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage. Specifically, this includes:

[0149] When the target voltage type is the target zero-current dynamic voltage, the current SOC, battery polarization degradation parameter mapping relationship, static OCV-SOC mapping relationship, and first duration are obtained. The first duration is the duration during which the current current of the energy storage battery is less than a first value. The first value is the minimum value between a first product and a first preset current, where the first product is the product of a preset percentage and the current ratio of the energy storage battery. The battery polarization degradation parameter mapping relationship includes the battery polarization degradation parameter charging mapping relationship and the battery polarization degradation parameter discharging mapping relationship. The battery polarization degradation parameter charging mapping relationship includes the mapping relationship between multiple durations, multiple SOCs, and multiple OCV conversion coefficients under charging conditions. The battery polarization degradation parameter discharging mapping relationship includes the mapping relationship under discharging conditions. The mapping relationships between multiple durations, multiple SOCs, and multiple OCV conversion coefficients; there is a one-to-one correspondence between duration and SOC, and a one-to-one correspondence between SOC and OCV conversion coefficient; the static OCV-SOC mapping relationship includes the discharge static OCV-SOC mapping relationship and the charging static OCV-SOC mapping relationship; the discharge static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the discharge state for the target static voltage; the charging static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the charging state for the target static voltage; there is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0150] When the target operating state is the charging state, the OCV conversion coefficient corresponding to both the current SOC and the first duration in the battery polarization decay parameter charging mapping relationship is determined as the target OCV conversion coefficient.

[0151] The ratio of the current single-cell voltage to the target OCV conversion factor is determined as the converted single-cell voltage.

[0152] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the converted single-cell voltage in the static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0153] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the converted cell voltage in the discharge static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0154] For example, the battery polarization degradation parameter charging mapping relationship provided in the embodiments of this application is shown in Tables 3-1 to 3-4.

[0155] Table 3-1

[0156] Duration (min) / SOC (%) 1 3 5 7 0 0.955628504 0.963337268 0.967910888 0.971341104 5 0.99033971 0.99193085 0.992674813 0.993186616 10 0.994503779 0.996283805 0.99681469 0.997085747 15 0.994682505 0.996019653 0.996641582 0.996983643 20 0.99536824 0.996257784 0.996932609 0.997178001 25 0.994589872 0.996277878 0.99694908 0.997406718 30 0.995504389 0.996628292 0.997053552 0.997539564 60 0.995446128 0.996964085 0.997298036 0.997753423 70 0.995245018 0.996123327 0.996750343 0.997213641 90 0.995920326 0.99688025 0.997390209 0.997720182 95 0.995351906 0.996551414 0.997091193 0.997481033 100 0.996351906 0.997551414 0.998091193 0.998481033

[0157] Table 3-2

[0158] Duration (min) / SOC (%) 9 11 13 15 0 0.974107406 0.976283564 0.978201534 0.979824432 5 0.983602457 0.994018297 0.994210223 0.994466125 10 0.997376803 0.997626632 0.997751546 0.99787646 15 0.997139126 0.997418994 0.99754338 0.997729958 20 0.997546088 0.997699457 0.997883501 0.997975522 25 0.997742319 0.997986393 0.998199957 0.998321994 30 0.99778257 0.997995201 0.998177455 0.998329334 60 0.99787486 0.998178451 0.998269529 0.998421324 70 0.997516506 0.997789085 0.997940517 0.998182809 90 0.997900168 0.998110151 0.998200144 0.998350132 95 0.997720934 0.997930848 0.998050799 0.998200738 100 0.998720934 0.998930848 0.999050799 0.999200738

[0159] Table 3-3

[0160] Duration (min) / SOC (%) 17 20 25 29.5 0 0.981189141 0.982958575 0.985209501 0.987016819 5 0.994690039 0.995009916 0.995457744 0.995809609 10 0.998032603 0.998188745 0.998438573 0.998594716 15 0.997823248 0.99797873 0.998196405 0.98382984 20 0.998128892 0.998343609 0.998527653 0.998619674 25 0.99847454 0.998627086 0.99884065 0.999023706 30 0.998420461 0.998541964 0.99878497 0.998876097 60 0.998512402 0.998664197 0.998815993 0.998967789 70 0.998273669 0.998485674 0.998727967 0.998909686 90 0.99850012 0.998590113 0.998770098 0.998920086 95 0.998350676 0.998500615 0.998680541 0.99883048 100 0.999350676 0.999500615 0.999680541 0.99983048

[0161] Table 3-4

[0162] Duration (min) / SOC (%) 44.5 59.5 89.5 119.5 150 180 0 0.990631455 0.992955149 0.996016524 0.997786058 0.998041015 5 0.996705265 0.997408995 0.998400614 0.999136332 0.999680123 1 10 0.99893823 0.999188058 0.999562801 0.999750172 0.999906314 15 0.998787238 0.99903601 0.999378071 0.999689035 0.999844518 20 0.999018435 0.999263826 0.999570565 0.999754609 0.999907978 1 25 0.998328798 0.999511853 0.999725417 0.999877963 1 1 30 0.999210231 0.999453237 0.999696243 0.999848121 0.999939249 1 60 0.99927138 0.999453535 0.999696409 0.999848204 0.999939282 1 70 0.999273124 0.990515416 0.999757708 0.999848567 1 1 90 0.999220062 0.999400048 0.999610031 0.999760019 0.99988001 1 95 0.999190332 0.999370258 0.999670135 0.999820074 0.999910037 1 100 1.000190332 1.000370258 1.000670135 1.000820074 0.999980037 1

[0163] It should be noted that Tables 3-1 to 3-4 together constitute an example of the charging mapping relationship of the entire battery polarization degradation parameters, and the data in Tables 3-1 to 3-4 are for illustrative purposes only and are not intended to limit this application. For example, in Table 3-1, the OCV conversion coefficient corresponding to a duration of 1 min and a SOC of 5% is 0.99033971. Similarly, in Table 3-2, the OCV conversion coefficient corresponding to a duration of 9 min and a SOC of 5% is 0.983602457; in Table 3-3, the OCV conversion coefficient corresponding to a duration of 17 min and a SOC of 10% is 0.998032603; and in Table 3-4, the OCV conversion coefficient corresponding to a duration of 44.5 min and a SOC of 15% is 0.998787238.

[0164] For example, the discharge mapping relationship of battery polarization degradation parameters provided in the embodiments of this application is shown in Tables 4-1 to 4-4.

[0165] Table 4-1

[0166] Duration (min) / SOC (%) 1 3 5 7 5 1.006895 1.005874 1.005204 1.004789 10 1.006274 1.004721 1.004255 1.003821 15 1.006332 1.005159 1.00451 1.004139 25 1.006078 1.004954 1.004407 1.004012 30 1.005691 1.004752 1.004359 1.003965 50 1.005833 1.00414 1.003687 1003203 60 1.004763 1.003949 1.003648 1.003256 70 1.004968 1.00401 1.003621 1.003232 90 1005506 1003711 1.003262 1.002783 95 1.005266 1.00392 1.003381 1002813 100 1.01336 1.009056 1.007143 1.005977

[0167] Table 4-2

[0168] Duration (min) / SOC (%) 9 11 13 15 17 5 1.004469 1.004214 1.003863 1.003639 1.003448 10 1003479 1.003168 1002951 1.002764 1002578 15 1.003861 1.003614 1.003336 1.003151 1.002965 25 1.003769 1.003586 1.003343 1.003191 1.003039 30 1.003663 1.003542 1.003299 1.003178 1.002936 50 1.002962 100272 1.002569 1.002387 1.002236 60 1.003105 1.002924 1.002834 1.002683 1.002593 70 1.002993 1.002843 1.002693 1.002544 1.002394 90 1002604 1.002364 1.002215 1.002065 1.001915 95 1002663 1.002334 1.002184 1.002005 1001885 100 1.0052 1.004633 1.004244 1.003826 1.003586

[0169] Table 4-3

[0170] Duration (min) / SOC (%) 20 25 30 45 60 5 1.003128 1.002682 1.002362 1.001692 1.001277 10 1.00233 1001957 1.001771 1.001274 1.000963 15 1.002749 1.002409 1.002101 1.001544 1.001143 25 1.002857 1.002492 1.002127 1.001489 1.001094 30 1.002785 1.002422 1.002119 1.001392 1.000999 50 1.001995 1001753 1001511 1001028 1.000725 60 1.002442 1002201 1001959 1.001326 1.000814 70 1.002244 1.002005 1.001766 1.001197 1.000868 90 1001766 1.001586 1.001377 1.000958 1.000718 95 1001706 1.001496 1.001257 1.000928 1.000688 100 1.003198 1.00275 1.002421 1.001733 1.001345

[0171] Table 4-4

[0172] Duration (min) / SOC (%) 90 120 150 180 5 1.000798 1.000511 1.000287 1 10 1.000621 1.000373 1.000217 1 15 1.000772 1.000463 1.000247 1 25 1.000638 1.000334 1.000152 1 30 1.000515 1.000272 1.000061 1 50 1.000423 1.000272 1.000151 1 60 1.000482 1.000301 1.00009 1 70 1.000479 1.000239 1.00009 1 90 1.000389 1000239 1.00009 1 95 1.000389 1.000209 1.00012 1 100 1.000837 1.000448 1.000239 1

[0173] It should be noted that Tables 4-1 to 4-4 together form an example of the discharge mapping relationship of the entire battery polarization degradation parameters, and the data in Tables 4-1 to 4-4 are for illustrative purposes only and are not intended to limit this application. For example, in Table 4-1, the OCV conversion coefficient corresponding to a duration of 1 min and a SOC of 5% is 1.006895. Similarly, in Table 4-2, the OCV conversion coefficient corresponding to a duration of 9 min and a SOC of 5% is 1.004469; in Table 4-3, the OCV conversion coefficient corresponding to a duration of 25 min and a SOC of 15% is 1.002409; and in Table 4-4, the OCV conversion coefficient corresponding to a duration of 120 min and a SOC of 90% is 1.000463.

[0174] It should be noted that the dynamic voltage is converted to its OCV when completely at rest, obtained according to the battery polarization degradation parameter mapping relationship, which is obtained from actual energy storage battery testing. Data is extracted from the raw data of OCV-SOC test, and the ratio of the single cell voltage at a specified time to the single cell voltage at 180 minutes is recorded.

[0175] In some other implementations, the target sub-corrected SOC of the energy storage battery is determined based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage. Specifically, this includes:

[0176] When the target voltage type is a target non-zero current dynamic voltage, the non-zero current dynamic voltage mapping relationship is obtained. The non-zero current dynamic voltage mapping relationship includes the charging non-zero current dynamic voltage mapping relationship and the discharging non-zero current dynamic voltage mapping relationship. The charging non-zero current dynamic voltage mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the charging state for the target non-zero current dynamic voltage. The discharging non-zero current dynamic voltage mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the discharging state for the target non-zero current dynamic voltage. There is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0177] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the dynamic voltage mapping relationship of the non-zero charging current is determined as the target sub-corrected SOC.

[0178] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the dynamic voltage mapping relationship of the non-zero discharge current is determined as the target sub-corrected SOC.

[0179] For example, the dynamic voltage mapping relationship of non-zero charging current provided in the embodiments of this application is shown in Table 5.

[0180] Table 5

[0181] Temperature (°C) / Sub-corrected SOC (%) 55 60 65 70 85 95 98 100 5 3423 3431 3438 3446 3463 3490 3510 3550 10 3381 3392 3400 3405 3414 3475 3521 3550 25 3355 3363 3380 3385 3395 3440 3525 3550

[0182] It should be noted that the data in Table 5 above are for illustrative purposes only and are not intended to limit this application. For example, in Table 5, the sub-corrected SOC corresponding to a temperature of 5°C and a single-cell voltage of 3426mV is 55%.

[0183] For example, the dynamic voltage mapping relationship of non-zero discharge current provided in the embodiments of this application is shown in Table 6.

[0184] Table 6

[0185] Temperature (°C) / Sub-corrected SOC (%) 0 5 10 15 20 -20 1500 2721 2948 3019 3250 -10 1800 2741 2968 3039 3244 -5 2000 2761 2988 3059 3245 0 2000 2896 3070 3114 3235 5 2300 2969 3102 3134 3227 10 2500 3043 3134 3154 3217 25 2500 3070 3161 3176 3211

[0186] It should be noted that the data in Table 6 above are for illustrative purposes only and are not intended to limit this application. For example, in Table 6, the sub-corrected SOC corresponding to a temperature of 5°C and a single-cell voltage of 2300mV is 0%.

[0187] In some implementations, the method further includes:

[0188] Under the condition of satisfying the first preset update, the maximum cell voltages corresponding to the energy storage battery under multiple first reference SOCs are obtained. If all the maximum cell voltages pass the verification, the dynamic voltage SOC accuracy mapping relationship of the charging non-zero current is updated according to all the maximum cell voltages.

[0189] The first preset update conditions include: the target total SOC correction accuracy is greater than the fourth accuracy threshold; the consistency difference of the energy storage battery is less than or equal to the consistency threshold; the battery management system is in a charging state; and the average temperature of the battery management system is greater than or equal to the first temperature threshold.

[0190] For example, the first reference SOC can be set according to the actual situation, and is not limited here. For example, the first reference SOC may include 55%, 60%, 65%, 70%, 90%, 95%, 98%, and 100%.

[0191] Optionally, the charging status can be distinguished as full charge or fast charge, and the dynamic voltage corresponding to the same SOC will be different.

[0192] Optionally, when the actual SOC is equal to its corresponding first reference SOC, the maximum cell voltage UcellMax at this moment is recorded to obtain multiple maximum cell voltages.

[0193] For example, the maximum cell voltages corresponding to the multiple first reference SOCs are arranged in descending or ascending order according to the magnitude of the first reference SOCs. If any two adjacent values ​​of the arranged maximum cell voltages are increasing or decreasing, and the absolute value of the difference from the historical value is within 20mV, then all maximum cell voltages are determined to have passed the verification; otherwise, all maximum cell voltages are determined to have failed the verification.

[0194] For example, if the first reference SOC includes 55%, 60%, 65%, 70%, 90%, 95%, 98%, and 100%, and the corresponding maximum voltage cells are 3331mV, 3335mV, 3338mV, 3340mV, 3342mV, 3346mV, 3350mV, and 3360mV, with a historical value of 3350mV, then all maximum cell voltages pass the verification. Conversely, if the first reference SOC includes 55%, 60%, 65%, 70%, 90%, 95%, 98%, and 100%, and the corresponding maximum voltage cells are 3320mV, 3321mV, 3335mV, 3332mV, 3340mV, 3346mV, 3350mV, and 3360mV, then all maximum cell voltages fail the verification.

[0195] Optionally, the maximum cell voltage can be replaced with the corresponding cell voltage in the charging non-zero current dynamic voltage SOC accuracy mapping relationship to complete the update of the charging non-zero current dynamic voltage SOC accuracy mapping relationship.

[0196] For example, at a temperature of 10℃, the second reference SOC includes 55%, 60%, 65%, 70%, 90%, 95%, 98%, and 100%, and the corresponding maximum voltage cells are 3331mV, 3335mV, 3338mV, 3340mV, 3342mV, 3346mV, 3350mV, and 3360mV. If all maximum voltage cells pass the verification, then in Table 5, 3381 is replaced with 3331, 3392 with 3335, 3400 with 3338, 3405 with 3340, 3414 with 3342, 3475 with 3346, 3521 with 3350, and 3550 with 3360, to complete the update of the dynamic voltage SOC accuracy mapping relationship for non-zero charging current.

[0197] The fourth precision threshold can be set according to the actual situation and is not limited here. For example, a fourth precision threshold of 99% indicates that the SOC precision is very high and has just undergone full charge or full discharge correction.

[0198] The consistency threshold can be set according to the actual situation and is not limited here. For example, the consistency threshold can be 5%. By setting the consistency difference of the energy storage battery to be less than or equal to the consistency threshold, it is possible to prevent large errors from occurring between the adaptive learning and normal values ​​due to sudden consistency differences.

[0199] The first temperature threshold can be set according to the actual situation and is not limited here. For example, the second temperature threshold can be 2℃.

[0200] Optionally, the average temperature of the battery management system is greater than or equal to a second temperature threshold, which can eliminate invalid charging (such as heating without charging) and improve the accuracy of the target SOC.

[0201] Optionally, the updated charging non-zero current dynamic voltage SOC accuracy mapping relationship can be stored and latched after power-off.

[0202] It should be added that if the difference is too small, the correction should be abandoned to prevent overcorrection. For example, if the absolute value of the difference between the target sub-corrected SOC and the current SOC is less than or equal to 3%, the correction should be stopped.

[0203] In some implementations, the method further includes:

[0204] Under the condition of satisfying the second preset update, the minimum cell voltages corresponding to the energy storage battery under multiple second reference SOCs are obtained. If all minimum cell voltages pass the verification, the dynamic voltage SOC accuracy mapping relationship of the discharge non-zero current is updated according to all minimum cell voltages.

[0205] The second preset update conditions include: the target total SOC correction accuracy is greater than the fourth accuracy threshold; the consistency difference of the energy storage battery is less than or equal to the consistency threshold; the battery management system is not in a charging state; and the average temperature of the battery management system is greater than or equal to the second temperature threshold.

[0206] Optionally, the second reference SOC can be set according to the actual situation, and is not limited here. For example, the second reference SOC may include 0%, 5%, 10%, 15%, and 20%.

[0207] Optionally, when the actual SOC is equal to its corresponding second reference SOC, the minimum cell voltage UcellMin at this moment is recorded to obtain multiple minimum cell voltages.

[0208] Optionally, the minimum cell voltages corresponding to the multiple second reference SOCs are arranged in descending or ascending order according to the size of the second reference SOCs. If any two adjacent values ​​of the arranged minimum cell voltages are increasing or decreasing, and the absolute value of the difference from the historical value is within 20mV, then all minimum cell voltages are determined to have passed the verification; otherwise, all minimum cell voltages are determined to have failed the verification.

[0209] For example, if the second reference SOC includes 0%, 5%, 10%, 15%, and 20%, the corresponding minimum voltage cells are 2331mV, 2335mV, 2338mV, 2340mV, and 2360mV, with a historical value of 2350mV. In this case, all minimum cell voltages are determined to have passed the verification. Conversely, if the second reference SOC includes 0%, 5%, 10%, 15%, and 20%, the corresponding minimum voltage cells are 2321mV, 2335mV, 2332mV, 2340mV, and 2360mV. In this case, all minimum cell voltages are determined to have failed the verification.

[0210] Optionally, the minimum cell voltage can be replaced with the corresponding cell voltage in the dynamic voltage SOC accuracy mapping relationship of the discharge non-zero current to complete the update of the dynamic voltage SOC accuracy mapping relationship of the discharge non-zero current.

[0211] For example, at a temperature of -10℃, the second reference SOC includes 0%, 5%, 10%, 15%, and 20%, and the corresponding minimum voltage cells are 2331mV, 2335mV, 2338mV, 2340mV, and 2360mV. If all minimum voltage cells pass the verification, then in Table 6, 1800 is replaced with 2331, 2741 with 2335, 2968 with 2338, 3039 with 2340, and 3244 with 2360, to complete the update of the dynamic voltage SOC accuracy mapping relationship for non-zero discharge current.

[0212] The second temperature threshold can be set according to actual conditions and is not limited here. For example, the second temperature threshold can be -20℃.

[0213] Optionally, if the average temperature of the battery management system is greater than or equal to a second temperature threshold, it can exclude severely low-temperature conditions and improve the accuracy of the target SOC. Severely low temperatures can cause the mapping relationship between non-zero current dynamic voltage and SOC accuracy to fluctuate randomly and become unstable, leading to inaccurate SOC correction.

[0214] Optionally, the updated dynamic voltage SOC accuracy mapping relationship for non-zero discharge current can be stored and latched after power-down.

[0215] In step S130, after determining the target sub-corrected SOC of the energy storage battery, the electronic device can also determine the target total SOC correction accuracy of the energy storage battery based on the target voltage type and the target sub-corrected SOC.

[0216] SOC correction accuracy characterizes the degree of SOC error at a given moment, and is mainly related to the current integral cumulative capacity, the type of SOC correction algorithm, and whether correction is performed. A SOC accuracy estimation model is developed, and the enabling timing of the error correction model is determined based on the accuracy level (i.e., when the target total SOC correction accuracy is greater than the current SOC accuracy, the target SOC is determined based on the target total SOC correction accuracy, the current SOC, and the target sub-corrected SOC), thus addressing the problems of incorrect or missed corrections.

[0217] SOC accuracy correction for lithium iron phosphate battery cell voltage OCV-SOC is performed within a range where relevant characteristics are relatively good. After quantification, the better the relevant characteristics, the higher the accuracy and the smaller the grade. The accuracy of the SOC value (0-100%, the larger the value, the higher the accuracy) is calculated based on "OCV-SOC within a range where relevant characteristics are relatively good", the first duration, the second duration, and "the number of capacity cycles since the last correction".

[0218] During long-term cycling, the accumulated integral error of SOC (State of Charge) increases, requiring algorithmic strategies to correct it, reduce the accumulated error, and ultimately improve SOC accuracy. Each correction algorithm needs to provide not only the corrected SOC value but also its correction accuracy. A comprehensive assessment is then taken into account before deciding whether to implement the correction. Optionally, outliers in parameters such as minimum cell voltage and average temperature should be removed and filtered.

[0219] When the current is smaller (absolute value less than 5A, tentatively), the duration is longer, and the cell voltage is in a range with good linearity (SOC≤30%, 60%≤SOC≤70%, SOC≥96%, the terminal voltage corresponding to SOC), the weight of SOCRect will become larger and larger, and the weight of AcuurSOCRect (converted to 0-1) will eventually approach 1.

[0220] In some implementations, the target total SOC correction accuracy of the energy storage battery is determined based on the target voltage type and the target sub-corrected SOC, specifically including:

[0221] When the target voltage type is either the target static voltage or the target zero-current dynamic voltage, the target resting time and the static OCV-SOC accuracy mapping relationship are obtained. The target resting time includes the sleep time of the battery management system and one of the first durations. The first value is the minimum value of the first product and the first preset current. The first product is the product of the preset percentage and the current ratio of the energy storage battery. The first duration is the duration during which the current of the energy storage battery is less than the first value. The static OCV-SOC accuracy mapping relationship includes the correspondence between multiple resting times, multiple sub-corrected SOCs and multiple accuracies. The resting time corresponds one-to-one with the sub-corrected SOC, and the sub-corrected SOC corresponds one-to-one with the accuracy.

[0222] In the static OCV-SOC accuracy mapping relationship, the accuracy corresponding to both the target static time and the target sub-corrected SOC is determined as the target total SOC correction accuracy.

[0223] For example, the static OCV-SOC accuracy mapping relationship provided in the embodiments of this application is shown in Tables 7-1 and 7-2.

[0224] Table 7-1

[0225] Sub-corrected SOC (%) / Settling time (min) 0 3 5 10 15 20 25 30 31 54 1 46 46 45 45 43 41 39 44 25 22 3 64 63 62 62 59 56 54 46 27 23 5 70 69 69 68 65 61 59 49 28 24 9 76 76 75 74 70 67 65 51 29 26 11 78 77 77 76 72 68 66 54 31 27 15 82 81 80 80 76 72 70 57 33 29 20 85 84 83 82 78 74 72 60 34 30 30 88 87 87 86 81 77 75 63 36 32 60 94 93 92 91 86 82 80 67 38 33 120 98 97 96 95 90 86 83 70 40 35 150 99 98 97 96 92 87 84 74 42 37 180 100 100 100 100 99 98 95 77 44 39

[0226] Table 7-2

[0227] Sub-corrected SOC (%) / Settling time (min) 55 60 65 70 71 94 95 98 100 1 38 39 39 36 25 22 25 44 43 3 40 54 54 38 27 23 27 46 59 5 42 59 59 40 28 24 28 49 65 9 44 65 65 44 29 26 29 51 70 11 46 66 66 46 31 27 31 54 72 15 49 70 70 49 33 29 33 57 76 20 51 72 72 51 34 30 34 60 78 30 54 75 75 54 36 32 36 70 81 60 57 80 80 57 38 33 38 81 86 120 60 83 83 60 40 35 40 82 90 150 63 84 84 63 42 37 42 86 92 180 66 95 95 66 44 39 65 90 99

[0228] It should be noted that Tables 7-1 and 7-2 together constitute an example of a complete static OCV-SOC accuracy mapping relationship, and the data in Tables 7-1 and 7-2 are for illustrative purposes only and are not intended to limit this application. For example, in Table 7-1, the accuracy corresponding to a resting time of 1 min and a sub-corrected SOC of 0% is 46%. Similarly, in Table 7-2, the accuracy corresponding to a resting time of 60 min and a sub-corrected SOC of 3% is 54%.

[0229] In other implementations, the target total SOC correction accuracy of the energy storage battery is determined based on the target voltage type and the target sub-corrected SOC, specifically including:

[0230] When the target voltage type is the target non-zero current dynamic voltage, the non-zero current dynamic voltage SOC accuracy mapping relationship and the current current of the energy storage battery are obtained. The non-zero current dynamic voltage SOC accuracy mapping relationship includes the charging non-zero current dynamic voltage SOC accuracy mapping relationship and the discharging non-zero current dynamic voltage SOC accuracy mapping relationship. The charging non-zero current dynamic voltage SOC accuracy mapping relationship includes the mapping relationship between multiple currents, multiple sub-corrected SOCs and multiple accuracies under the charging state. The discharging non-zero current dynamic voltage SOC accuracy mapping relationship includes the mapping relationship between multiple currents, multiple sub-corrected SOCs and multiple accuracies under the discharging state. There is a one-to-one correspondence between current and sub-corrected SOC, and a one-to-one correspondence between sub-corrected SOC and accuracy.

[0231] When the target operating state is charging, the accuracy corresponding to both the current current and the target sub-corrected SOC in the dynamic voltage SOC accuracy mapping relationship of non-zero charging current is determined as the target total SOC correction accuracy.

[0232] When the target operating state is the discharge state, the accuracy corresponding to both the current current and the target sub-corrected SOC in the dynamic voltage SOC accuracy mapping relationship of the non-zero discharge current is determined as the target total SOC correction accuracy.

[0233] For example, the non-zero current dynamic voltage SOC accuracy mapping relationship provided in the embodiments of this application is shown in Tables 8-1 and 8-2.

[0234] Table 8-1

[0235] <![CDATA[Sub-corrected SOC (%) / Current (C1)]]> 0 3 5 10 15 20 25 30 31 54 0.05 42 43 42 42 41 41 41 35 19 17 0.1 100 99 98 97 96 95 96 80 40 35 0.5 97 96 95 87 86 86 86 72 36 32 1 80 79 78 78 77 76 77 48 24 21 2 40 40 39 39 38 38 38 32 16 14

[0236] Table 8-2

[0237] <![CDATA[Sub-corrected SOC (%) / Current (C1)]]> 55 60 65 70 71 94 95 98 100 0.05 31 39 39 31 19 21 31 41 43 0.1 70 90 90 70 40 45 70 96 100 0.5 63 81 81 63 36 41 63 90 97 1 56 72 72 56 32 36 56 77 80 2 28 36 36 28 16 18 28 38 40

[0238] It should be noted that Tables 8-1 and 8-2 together provide an example of the accuracy mapping relationship for a non-zero current dynamic voltage SOC, and the data in Tables 8-1 and 8-2 are for illustrative purposes only and are not intended to limit this application. For example, in Table 8-1, the accuracy corresponding to a current of 0.05C and a sub-corrected SOC of 0% is 42%. Similarly, in Table 8-2, the accuracy corresponding to a current of 1C and a sub-corrected SOC of 55% is 56%.

[0239] Optionally, the mapping relationship between the non-zero current dynamic voltage SOC accuracy can be obtained through actual energy storage battery testing. The main testing principle is to perform multiple charge and discharge tests (without enabling any correction algorithm, and without full charge, full discharge, or rest), record the SOC and current values ​​calculated by the dynamic voltmeter at each moment, and calculate the average value. The last test involves a full charge or full discharge, at which point the initial SOC value is relatively accurate (100%, 0%). Then, the data is retrieved by manual Ah integration to obtain the SOC value at different points, which is then compared with the previous value to obtain the accuracy.

[0240] It should be noted that data not found in the above tables can be determined using linear interpolation.

[0241] In step S140, after determining the target total SOC correction accuracy of the energy storage battery based on the target voltage type and the target sub-corrected SOC, the electronic device can also determine the target SOC based on the target total SOC correction accuracy, the current SOC, and the target sub-corrected SOC if the target total SOC correction accuracy is greater than the current SOC accuracy.

[0242] Optionally, if the total target SOC correction accuracy is less than or equal to the current SOC accuracy, it indicates that the current SOC accuracy is high, and the current SOC is determined as the target SOC.

[0243] Optionally, the target SOC can be the SOC obtained by modifying the current SOC.

[0244] In some implementations, the target SOC is determined based on the target total SOC correction accuracy, the current SOC, and the target sub-correction SOC. Specifically, this includes: determining the difference between the preset value and the target total SOC correction accuracy as a first accuracy difference; determining the product of the target total SOC correction accuracy and the target sub-correction SOC as a first accuracy product; and determining the target SOC by summing the product of the current SOC and the first accuracy difference with the first accuracy product.

[0245] Optionally, the default value can be "1", but it can also be other values, which are not limited here.

[0246] In other words, the target SOC satisfies formula (4), which can be: SOCRect=SOC(t)*(1-AcuurSOCSubRect)+AcuurSOCSubRect*SOCSubRect.

[0247] Where SOCRect is the target SOC, AcuurSOCSubRect is the target total SOC correction accuracy, SOCSubRect is the target sub-corrected SOC, and SOC(t) is the current SOC.

[0248] For example, after a correction algorithm is triggered at time t0, the initial value of the ampere-hour integral or the initial value of the entire SOC when the low-voltage electricity on the energy storage battery is working, SOC(t0), satisfies formula (5), which includes: SOC(t0) = SOCRect. The SOC value SOCAh(t) calculated by the ampere-hour integral satisfies formula (6), which includes: / CN; where i is the current, k is the charge / discharge capacity efficiency (temporarily set to 1), t0 and t2 represent two different times; CN is the calibrated value of the energy storage battery capacity, or the actual usable capacity value of the energy storage. The real-time SOC value at time t+1, SOC(t+1), satisfies formula (7), which includes: SOC(t+1) = SOC(t0) + SOCAh(t). SOC(t+1) is also the initial value updated after a certain correction of SOC time energy, and the ampere-hour integration starts again.

[0249] It should be added that the ampere-hour integration method is also called the current integration method or the coulomb counting method. The basic idea of ​​the current integration method is to accurately measure the charging and discharging current and time of the battery, and then integrate the current over the time interval t0 to t to obtain the amount of charge or discharge of the battery in any time interval. Dividing this amount by the capacity value gives the battery's SOC value. The calculation expression of the current integration method is shown in formula (8).

[0250] (8)

[0251] Where SOC0 is the initial SOC; SOC is the current SOC; CN is the rated value of the capacity; i is the current; and k is the charge / discharge capacity efficiency, which is tentatively set to 1 here and can be determined later based on the actual rated value. This represents the total amount of electricity discharged by the energy storage battery during the time period 0-t. Due to the cumulative error in current integration, SOC0 and CN need to be continuously corrected to ensure the accuracy of the current SOC.

[0252] In embedded software, the task cycle (1000ms) of the SOC in the BMS system is longer than the current acquisition cycle (10ms). If the SOC task cycle is set too small, it can easily cause the BMS software system to crash; if it is set too long, it will lead to accumulated errors in the integration stage. Considering all factors, an additional pure current integration module needs to be set up outside the SOC unit module task to perform current pre-integration before passing it to the SOC unit module. For example, first perform 100 rolling current accumulations of 10ms each, converting Amperes (A) * ms to A * seconds (s), and then pass it to the SOC unit module. The ratio of A * ms to A * hours (h) is 1 / (3600000). If the SOC integration task timing cycle is inaccurate, variable step size integration can be considered.

[0253] Optionally, when the current SOC is inaccurate but the accurate current SOC is known, the current SOC can be set via a host computer or remote calibration. After successful calibration, the current SOC is changed only once; subsequent SOC changes will still be based on the ampere-hour integration. When calibrating the current SOC, if the calibrated SOC changes (e.g., >1%) and the calibration status is valid, then the current SOC equals the calibrated SOC.

[0254] In this embodiment, when the BMS system starts working after low-voltage power-on, it acquires the current State of Charge (SOC) and begins periodically performing ampere-hour integration calculations. It also acquires the current SOC in real time. Through the intelligent SOC correction control model, based on the target total SOC correction accuracy and the current correction algorithm, it intelligently and adaptively decides whether to use the correction method and its weight, corrects the current SOC value, performs ampere-hour integration again, and monitors for the next correction opportunity. The intelligent SOC correction control model includes a full-charge correction algorithm, a full-discharge correction algorithm, a zero-current dynamic voltage correction algorithm, and a non-zero-current dynamic voltage correction algorithm.

[0255] Optional, full charge correction algorithm: When the BMS system is fully charged, full charge correction is performed: the maximum cell voltage reaches the full charge cutoff voltage (≥3.55V), the current is relatively small (≤max(0.1C1, 5A),) and this continues for a certain period of time (≥3s), then full charge correction is performed, the SOC correction is 100%, and the total correction accuracy is 100%. This full charge SOC correction method has the highest accuracy, and correction is enabled as long as the full charge conditions are met.

[0256] Optional, full discharge correction algorithm: When the BMS system is fully discharged, full discharge correction is performed: the minimum cell voltage reaches the full charge cutoff voltage (≤2.8V), the current is small (≤max(0.1C1, 5A)), and this continues for a certain period of time (≥20s), then full discharge correction is performed, the SOC correction is 0%, and the total correction accuracy is 99%. This correction method is enabled only if the full discharge condition is met and the target total SOC correction accuracy is ≤99%.

[0257] Optionally, the minimum cell voltage can be differentiated based on temperature. For example, at extremely low temperatures (≤-20℃), the minimum cell voltage is ≤1.5V, and the current is ≤max(0.1C1, 5A) for 20 seconds; at low temperatures (≤0℃), the minimum cell voltage is ≤2V, and the current is ≤0.1C1 for 20 seconds; at normal temperatures (>0℃), the minimum cell voltage is ≤2.8V, and the current is ≤max(0.1C1, 5A) for 20 seconds. The specific values ​​are determined based on the cell performance.

[0258] Optional zero-current dynamic voltage correction algorithm: The zero-current dynamic voltage correction method is used when the current is less than Min (0.01C1, 5A), the first duration is less than the second preset duration (time threshold, temperature-dependent, -40-0℃ maps to 1-3h), and the cell voltage OCV-SOC is in the non-plateau range. This correction method is enabled only if this condition is met and the current SOC accuracy is ≤95% (i.e., the second accuracy threshold). If the zero-current dynamic voltage correction algorithm is satisfied, the initial SOC(t0) value (i.e., the current SOC) is updated; otherwise, it is not updated. If the cell is not completely stationary, the dynamic voltage is first converted to its OCV when completely stationary, then the corresponding target sub-SOC correction and sub-correction accuracy (converted to 0-100%) are calculated, finally obtaining the total SOC correction and the target total correction accuracy.

[0259] Optional non-zero current dynamic voltage correction algorithm: When the BMS system has a high SOC during charging or a low SOC during discharging, and the BMS system has current greater than Min (0.01C1, 5A), then the non-zero current dynamic voltage correction method is used. The target total correction accuracy is AcuurSOCSubRect ≤ 92%. Under the premise that other preset correction conditions corresponding to non-zero current dynamic voltage are met, AcuurSOCSubRect ≤ 92% enables correction.

[0260] To better understand the method for determining the state of charge provided in the embodiments of this application, the following explanation is provided in conjunction with three specific calculation examples.

[0261] Example 1:

[0262] When the BMS system is powered on, the system sleep time is 61 minutes. Before sleep, it is in a discharge state. At this time, the individual cell voltage (i.e., the current individual cell voltage) is 3219mV, the temperature (i.e., the current temperature) is 25℃, the real-time SOC value (i.e., the current SOC) is 25%, and the current SOC accuracy is 80%. The current SOC accuracy is a real-time calculated value, obtained by formulas (1) to (3). Assume that the first preset duration, the second preset duration, and the third preset duration are all 15 minutes, and the first accuracy threshold is 97%.

[0263] At this point, the sleep duration is longer than the first preset duration, and the target voltage type is determined to be the target static voltage. The current single-cell voltage is in the low-segment non-plateau region, and the current SOC accuracy is less than the first accuracy threshold. Therefore, it is determined that the static OCV-SOC correction condition is met (i.e., the preset correction condition corresponding to the target static voltage). Using 25℃ and 3219mV, the discharge static OCV-SOC mapping relationship is consulted, i.e., Tables 1-1 and 1-2, to obtain the final target sub-corrected SOC, i.e., SOCSubRect=15;

[0264] Using SOCSubRect=15 and resting time=61 minutes (system hibernation time is 61 minutes), the static OCV-SOC accuracy is obtained by referring to Table 7-1 and Table 7-2, and the target total SOC correction accuracy is 86%. Since the target total SOC correction accuracy of 86% is greater than the current SOC accuracy of 80%, the target SOC is determined to be 15% according to the above formula (4).

[0265] Example 2:

[0266] After the BMS system is powered on, it discharges for a period of time and enters a high-voltage standby state. The current current is 3A, which is less than Min(0.01C1, 5A), and the duration (i.e., the first duration) is 20 minutes. At this time, the current unit voltage is 3200mV, the temperature is 25℃, and the real-time SOC value (i.e., the current SOC) is 20%. At this time, the accuracy of the current SOC is 90%. This accuracy of the current SOC is a real-time calculated value, obtained by formulas (1) to (3). Assume that the first preset duration, the second preset duration, and the third preset duration are all 25 minutes, and the second accuracy threshold is 97%.

[0267] 1) The current current is 3A, which is less than Min(0.01C1, 5A), and the duration (i.e., the first duration) is 20 minutes. This duration is less than the second preset duration of 25 minutes. Therefore, the target voltage type is determined to be the target zero-current dynamic voltage. At this time, the current single-cell voltage is in the low-segment non-platform region, and the current SOC accuracy is 90%, which is less than the second accuracy threshold of 97%, thus satisfying the preset correction conditions corresponding to the target zero-current dynamic voltage.

[0268] 2) Obtain the conversion OCV. First, using a duration of 20 minutes and a current SOC of 20%, refer to Tables 4-1 to 4-4 to obtain the OCV conversion coefficient of 0.998343609. The converted OCV is then calculated as 3200 / 0.998343609 = 3205mV.

[0269] 3) Obtain the SOC from the lookup table. Using 25℃ and 3205mV, refer to Tables 1-1 and 1-2 to obtain the target sub-corrected SOC, i.e., SOCSubRect = 10.6;

[0270] 4) Obtain the accuracy of the SOC lookup table. Using the resting time (i.e. the first duration) of 20 minutes and SOCSubRect (10.6), look up the "Static OCV-SOC Accuracy Table", i.e., look up Table 7-1 and Table 7-2, and then divide by 100 to obtain the target total SOC accuracy AcuurSOCSubRect = 0.815;

[0271] 5) The calculated target SOC is 12.3%, according to the above formula (4), that is

[0272] SOCRect=SOC(t)*(1-AcuurSOCSubRect)+AcuurSOCSubRect*SOCSubRect

[0273] =20*(1-0.815)+0.815*10.6

[0274] =12.3.

[0275] Reintegrate Ah. According to formulas (5) to (7) and (1) to (3), reintegrate Ah again to obtain the values ​​of SOC(t+1) and AcuurSOCRect(t+1) periodically;

[0276] Wait for the correction condition to be enabled again (i.e., the preset correction condition corresponding to the target voltage type is met). If the zero current condition (i.e., the preset correction condition corresponding to the target zero current dynamic voltage) is still met, then the correction is enabled once every 3 minutes, i.e., steps 1) to 6) are repeated until the zero current condition is no longer met.

[0277] Example 3:

[0278] After the BMS system is powered on, it charges for a period of time. The current current is 0.5C, which is greater than Min (0.01C1, 5A) and lasts for 6 minutes. At this time, the cell voltage (i.e., the current cell voltage) is 3530mV, the temperature (i.e., the current temperature) is 10℃, and the current SOC is 90%. At this time, the current SOC accuracy is 88%, and the third accuracy threshold is 92%.

[0279] 1) The current current is 0.5C, which is greater than Min(0.01C1, 5A), so the target voltage type is determined to be the target non-zero current dynamic voltage. The current SOC accuracy is 88%, which is less than the third accuracy threshold of 92%, thus meeting the enable condition (i.e., the preset correction condition).

[0280] 2) Obtain the SOC from the table. Using 10℃ and 3530mV, refer to the "Charging NZCurrUcell-SOC_Chrg Table", i.e., Table 5, to obtain the target sub-corrected SOC, i.e., SOCSubRect = 98.6%;

[0281] 3) Obtain the accuracy of the SOC lookup table. Using the current current of 0.5C and SOCSubRect (98.6%), look up the "Non-zero Current Dynamic Voltage Ucell_SOC Accuracy Table", that is, look up Tables 8-1 to 8-2, and then divide by 100 to obtain the target total SOC correction AccurSOCSubRect = 0.921;

[0282] 4) The calculated target SOC is 97.9%, according to the above formula (4), that is

[0283] SOCRect=SOC(t)*(1-AcuurSOCSubRect)+AcuurSOCSubRect *SOCSubRect

[0284] =90*(1-0.921)+0.921*98.6

[0285] =97.9.

[0286] 5) Reintegrate Ah. According to formulas (5) to (7) and (1) to (3), reintegrate Ah again to obtain the values ​​of SOC(t+1) and AcuurSOCRect(t+1) periodically;

[0287] 6) Wait for the correction condition to be enabled again (i.e., the preset correction condition corresponding to the target voltage type is met). If the non-zero current condition is still met (i.e., the preset correction condition corresponding to the target non-zero current dynamic voltage), the correction is enabled once every 3 minutes, i.e., steps 1) to 6) are repeated until the zero current condition is no longer met.

[0288] Optionally, the specific implementation methods and steps are as follows:

[0289] Obtain the cell parameter tables. Once the BMS battery system design is finalized, obtain the thermal cell parameter tables according to the specific project and battery, including the discharge static OCV-SOC table, the charge static OCV-SOC table, the static OCV-SOC accuracy table, the battery polarization degradation parameters - charging, the battery polarization degradation parameters - discharging table, the charging NZCurrUcell-SOC table, the discharging NZCurrUcell-SOC table, and the non-zero current dynamic voltage Ucell_SOC accuracy table.

[0290] The acquisition method is as follows:

[0291] Option 1: Provided by the cell company. This cell parameter table contains standard test items from cell suppliers, making it relatively convenient for them to provide.

[0292] Method 2: Physical testing. If this parameter cannot be obtained, physical testing is required.

[0293] The operation process of SOC estimation software.

[0294] Obtain the initial value. After the BMS system starts working at low voltage, after obtaining the initial SOC value, if the static lookup condition of voltage OCV-SOC is met, the initial SOC0 value is equal to that obtained by looking up the OCV-SOC table; otherwise, the initial SOC0 value is equal to that obtained by reading the SOC value stored in the EEPROM before the last sleep, SOCByNvm; otherwise, it is equal to the default value of 50%. At the same time, obtain the initial SOC accuracy AcuurSOCRect (t0).

[0295] Periodic Ah integration. According to formulas (2) to (4) and (6) to (8), Ah integration is performed again to periodically obtain the values ​​of SOC(t+1) and AcuurSOCRect(t+1);

[0296] Wait for the correction condition to be enabled again. If the correction condition is met, perform the correction and update the initial values ​​SOC(t0) and AcuurSOCRect(t0).

[0297] Waiting to update the non-zero current dynamic voltage correction NZCurrUcell-SOC table. If the update conditions are met, perform the update, and then power down to store and latch the data.

[0298] The embodiments of this application have at least the following beneficial effects: 1) Reduced SOC estimation error, ensuring that the SOC error will not get out of control under any extreme conditions, such as exceeding 30%. 2) Increased SOC correction opportunities. In addition to full charge, full discharge, and static voltage corrections, dynamic voltage-SOC correction opportunities are added; in addition to static dormancy correction conditions, small current equivalent static initial value correction opportunities are added. 3) Reduced SOC erroneous or missed corrections. An intelligent control model for SOC error correction is developed, which intelligently enables different SOC correction algorithms based on the actual accuracy of SOC estimation, reducing SOC erroneous or missed corrections. Example 2

[0299] This application also provides a charging method applicable to energy storage batteries, which may include steps S210 to S230.

[0300] S210. Determine the target SOC of the energy storage battery according to the method for determining the state of charge in Example 1.

[0301] S220. Based on the target SOC, determine the charging strategy. The charging strategy is used to characterize the charging speed of the energy storage battery.

[0302] S230, Execute the charging strategy to charge the energy storage battery.

[0303] For a detailed implementation of S210, please refer to Example 1, which will not be repeated here.

[0304] In step S220, for example, if the target SOC is greater than a first SOC threshold, the charging strategy is determined to be charging at a first charging rate; if the target SOC is less than or equal to the first SOC threshold, the charging strategy is determined to be charging at a second charging rate; the first charging rate is less than the second charging rate. The first SOC threshold, the first charging rate, and the second charging rate can all be set according to actual conditions, and are not limited here.

[0305] In other words, when the target SOC is low, fast charging is used to charge the energy storage battery; when the target SOC is high, slow charging is used to charge the energy storage battery. Example 3

[0306] like Figure 3 As shown in the figure, this application provides a SOC determination device for energy storage batteries. The device includes a first acquisition module 310, a first determination module 320, a second determination module 330, and a third determination module 340.

[0307] The first acquisition module 310 is used to acquire the target voltage type, target operating state, current SOC and current SOC accuracy of the energy storage battery when the battery management system is powered on. The target voltage type includes one of target static voltage, target zero current dynamic voltage and target non-zero current dynamic voltage; the target operating state includes one of charging state and discharging state; and the current SOC accuracy is used to characterize the total error of the current SOC of the energy storage battery.

[0308] The first determining module 320, connected to the first acquiring module 310, is used to determine the target sub-corrected SOC of the energy storage battery based on the target voltage type, target operating state, current temperature of the battery management system, and current cell voltage, provided that the preset correction conditions corresponding to the target voltage type are met.

[0309] The second determining module 330, connected to the first determining module 320, is used to determine the target total SOC correction accuracy of the energy storage battery based on the target voltage type and the target sub-corrected SOC; the target total SOC correction accuracy is used to characterize the total error of the target SOC of the energy storage battery.

[0310] The third determining module 340, connected to the second determining module 330, is used to determine the target SOC based on the target total SOC correction accuracy, the current SOC, and the target sub-corrected SOC when the target total SOC correction accuracy is greater than the current SOC accuracy.

[0311] In some implementations, the first acquisition module 310 is specifically used for:

[0312] Obtain the sleep duration of the battery management system and the current current of the energy storage battery;

[0313] If the sleep duration is greater than or equal to the first preset duration, or if the current current is less than the first value and the first duration is greater than or equal to the second preset duration, the target voltage type of the energy storage battery is determined to be the target static voltage; the first value is the minimum value between the first product and the first preset current, the first product is the product of the preset percentage and the current ratio of the energy storage battery, and the first duration is the duration during which the current current is less than the first value.

[0314] When the current is less than the first value and the first duration is less than the second preset duration, the target voltage type of the energy storage battery is determined to be the target zero current dynamic voltage.

[0315] When the current is greater than or equal to the first value, the target voltage type of the energy storage battery is determined to be the target non-zero current dynamic voltage.

[0316] In some implementations, the preset correction conditions corresponding to the target static voltage include:

[0317] The current single-cell voltage of the energy storage battery is in the non-plateau region, and the current SOC accuracy is less than or equal to the first accuracy threshold; the non-plateau region is the interval in the SOC-open circuit voltage OCV curve corresponding to the energy storage battery where the slope is greater than the preset slope.

[0318] The preset correction conditions corresponding to the target zero-current dynamic voltage include:

[0319] The current single-cell voltage of the energy storage battery is in the non-plateau region, and the current SOC accuracy is less than or equal to the second accuracy threshold.

[0320] The preset correction conditions corresponding to the target non-zero current dynamic voltage include:

[0321] The current SOC accuracy is less than or equal to the third accuracy threshold, and the absolute value of the fluctuation of the current current of the energy storage battery is less than or equal to the second preset current, and the second duration is greater than or equal to the third preset duration. The second duration is the duration during which the absolute value of the fluctuation is less than or equal to the second preset current.

[0322] The first accuracy threshold is greater than the second accuracy threshold, and the second accuracy threshold is greater than the third accuracy threshold.

[0323] In some implementations, the first determining module 320 is specifically used for:

[0324] When the target voltage type is the target static voltage, the static OCV-SOC mapping relationship is obtained. The static OCV-SOC mapping relationship includes the discharge static OCV-SOC mapping relationship and the charging static OCV-SOC mapping relationship. The discharge static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the discharge state for the target static voltage. The charging static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the charging state for the target static voltage. There is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0325] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the charging static OCV-SOC mapping relationship is determined as the target sub-corrected SOC;

[0326] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the discharge static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0327] In some implementations, the first determining module 320 is specifically used for:

[0328] When the target voltage type is the target zero-current dynamic voltage, the current SOC, battery polarization degradation parameter mapping relationship, static OCV-SOC mapping relationship, and first duration are obtained. The first duration is the duration during which the current current of the energy storage battery is less than a first value. The first value is the minimum value between a first product and a first preset current, where the first product is the product of a preset percentage and the current ratio of the energy storage battery. The battery polarization degradation parameter mapping relationship includes the battery polarization degradation parameter charging mapping relationship and the battery polarization degradation parameter discharging mapping relationship. The battery polarization degradation parameter charging mapping relationship includes the mapping relationship between multiple durations, multiple SOCs, and multiple OCV conversion coefficients under charging conditions. The battery polarization degradation parameter discharging mapping relationship includes the mapping relationship under discharging conditions. The mapping relationships between multiple durations, multiple SOCs, and multiple OCV conversion coefficients; there is a one-to-one correspondence between duration and SOC, and a one-to-one correspondence between SOC and OCV conversion coefficient; the static OCV-SOC mapping relationship includes the discharge static OCV-SOC mapping relationship and the charging static OCV-SOC mapping relationship; the discharge static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the discharge state for the target static voltage; the charging static OCV-SOC mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the charging state for the target static voltage; there is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0329] When the target operating state is the charging state, the OCV conversion coefficient corresponding to both the current SOC and the first duration in the battery polarization decay parameter charging mapping relationship is determined as the target OCV conversion coefficient.

[0330] The ratio of the current unit voltage to the target OCV conversion factor is determined as the converted unit voltage;

[0331] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the converted single-cell voltage in the charging static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0332] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the converted cell voltage in the discharge static OCV-SOC mapping relationship is determined as the target sub-corrected SOC.

[0333] In some implementations, the first determining module 320 is specifically used for:

[0334] When the target voltage type is a target non-zero current dynamic voltage, the non-zero current dynamic voltage mapping relationship is obtained. The non-zero current dynamic voltage mapping relationship includes the charging non-zero current dynamic voltage mapping relationship and the discharging non-zero current dynamic voltage mapping relationship. The charging non-zero current dynamic voltage mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the charging state for the target non-zero current dynamic voltage. The discharging non-zero current dynamic voltage mapping relationship includes the mapping relationship between multiple temperatures, multiple individual cell voltages, and multiple sub-corrected SOCs in the discharging state for the target non-zero current dynamic voltage. There is a one-to-one correspondence between temperature and individual cell voltage, and a one-to-one correspondence between individual cell voltage and sub-corrected SOC.

[0335] When the target operating state is the charging state, the sub-corrected SOC that corresponds to both the current temperature and the current single-cell voltage in the charging non-zero current dynamic voltage mapping relationship is determined as the target sub-corrected SOC.

[0336] When the target operating state is the discharge state, the sub-corrected SOC that corresponds to both the current temperature and the current cell voltage in the dynamic voltage mapping relationship of the non-zero discharge current is determined as the target sub-corrected SOC.

[0337] In some implementations, the second determining module 330 is specifically used for:

[0338] When the target voltage type is either the target static voltage or the target zero-current dynamic voltage, the mapping relationship between the target resting time and the static OCV-SOC accuracy is obtained. The target resting time includes the sleep time of the battery management system and one of the first durations, where the first duration is the duration during which the current current of the energy storage battery is less than a first value. The first value is the minimum value between the first product and the first preset current, where the first product is the product of the preset percentage and the current ratio of the energy storage battery. The static OCV-SOC accuracy mapping relationship includes the correspondence between multiple resting times, multiple sub-corrected SOCs and multiple accuracies, with a one-to-one correspondence between resting time and sub-corrected SOC, and a one-to-one correspondence between sub-corrected SOC and accuracy.

[0339] In the static OCV-SOC accuracy mapping relationship, the accuracy corresponding to both the target static time and the target sub-corrected SOC is determined as the target total SOC correction accuracy.

[0340] In some implementations, the second determining module 330 is specifically used for:

[0341] When the target voltage type is a target non-zero current dynamic voltage, the non-zero current dynamic voltage SOC accuracy mapping relationship and the current current of the energy storage battery are obtained. The non-zero current dynamic voltage SOC accuracy mapping relationship includes the charging non-zero current dynamic voltage SOC accuracy mapping relationship and the discharging non-zero current dynamic voltage SOC accuracy mapping relationship. The charging non-zero current dynamic voltage SOC accuracy mapping relationship includes the mapping relationship between multiple currents, multiple sub-corrected SOCs, and multiple accuracies under the charging state. The discharging non-zero current dynamic voltage SOC accuracy mapping relationship includes the mapping relationship between multiple currents, multiple sub-corrected SOCs, and multiple accuracies under the discharging state. There is a one-to-one correspondence between current and sub-corrected SOC, and a one-to-one correspondence between sub-corrected SOC and accuracy.

[0342] When the target operating state is the charging state, the accuracy corresponding to both the current current and the target sub-corrected SOC in the dynamic voltage SOC accuracy mapping relationship of the non-zero charging current is determined as the target total SOC correction accuracy.

[0343] When the target operating state is the discharge state, the accuracy corresponding to both the current current and the target sub-corrected SOC in the dynamic voltage SOC accuracy mapping relationship of the non-zero discharge current is determined as the target total SOC correction accuracy.

[0344] In some embodiments, the device further includes:

[0345] The first update module is used to obtain multiple maximum cell voltages corresponding to multiple first reference SOCs of the energy storage battery under the condition of satisfying the first preset update condition, and update the dynamic voltage SOC accuracy mapping relationship of charging non-zero current according to the condition that all maximum cell voltages pass the verification.

[0346] The first preset update conditions include: the target total SOC correction accuracy is greater than the fourth accuracy threshold; the consistency difference of the energy storage battery is less than or equal to the consistency threshold; the battery management system is in a charging state; and the average temperature of the battery management system is greater than or equal to the first temperature threshold.

[0347] In some embodiments, the device further includes:

[0348] The second update module is used to obtain multiple minimum cell voltages corresponding to multiple second reference SOCs of the energy storage battery under the condition of satisfying the second preset update condition, and update the dynamic voltage SOC accuracy mapping relationship of discharge non-zero current according to all minimum cell voltages when all minimum cell voltages pass the verification.

[0349] The second preset update conditions include: the target total SOC correction accuracy is greater than the fourth accuracy threshold; the consistency difference of the energy storage battery is less than or equal to the consistency threshold; the battery management system is not in a charging state; and the average temperature of the battery management system is greater than or equal to the second temperature threshold.

[0350] In some implementations, the first acquisition module 310 is specifically used for:

[0351] Obtain the initial SOC accuracy and the ampere-hour integration SOC accuracy; the initial SOC accuracy includes one of the historical SOC accuracy and the initial sub-correction SOC accuracy; the ampere-hour integration SOC accuracy is the SOC accuracy obtained through ampere-hour integration;

[0352] The difference between the initial SOC accuracy and the ampere-hour integral SOC accuracy is determined as the current SOC accuracy.

[0353] In some implementations, the third determining module 340 is specifically used for:

[0354] The difference between the preset value and the target total SOC correction accuracy is determined as the first accuracy difference;

[0355] The product of the total target SOC correction accuracy and the target sub-correction SOC is determined as the first accuracy product;

[0356] The product of the current SOC and the difference in first precision, and the sum of the products of the current SOC and the first precision, are used to determine the target SOC.

[0357] The SOC determination apparatus provided in this application embodiment has the beneficial effects and implementation methods of the state of charge determination method provided in embodiment 1 of this application. For details, please refer to the specific description of the state of charge determination method in embodiment 1 above. This embodiment will not repeat the description here. Example 4

[0358] This application embodiment also provides a charging system for an energy storage battery, the system comprising:

[0359] Such as the SOC determining device of any of the third aspects, used to determine the target SOC of the energy storage battery;

[0360] The strategy determination device, connected to the SOC determination device, is used to determine the charging strategy based on the target SOC. The charging strategy is used to characterize the charging speed of the energy storage battery.

[0361] An execution device, connected to a strategy determination device, is used to execute a charging strategy to charge the energy storage battery.

[0362] The charging system provided in this application has the beneficial effects and implementation methods of the charging method provided in embodiment 2 of this application. For details, please refer to the specific description of the charging method in embodiment 2 above. This embodiment will not repeat the description here.

[0363] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this application, and this application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this application, and these modifications and improvements are also considered to be within the scope of protection of this application.

Claims

1. A method of determining a state of charge (SOC), characterized by, The method is applied to a storage battery, and the method comprises the following steps: In the case that the battery management system is powered on, the target voltage type, the target working state, the current SOC and the current SOC accuracy of the storage battery are acquired, the target voltage type comprises one of the target static voltage, the target zero-current dynamic voltage and the target non-zero-current dynamic voltage, the target working state comprises one of the charging state and the discharging state, and the current SOC accuracy is used to represent the total error degree of the current SOC of the storage battery; In the case that the preset correction condition corresponding to the target voltage type is met, the target sub-correction SOC of the storage battery is determined according to the target voltage type, the target working state, the current temperature of the battery management system and the current single-cell voltage of the storage battery; The target total SOC correction accuracy of the storage battery is determined according to the target voltage type and the target sub-correction SOC, and the target total SOC correction accuracy is used to represent the total error degree of the target SOC of the storage battery; In the case that the target total SOC correction accuracy is greater than the current SOC accuracy, the target SOC is determined according to the target total SOC correction accuracy, the current SOC and the target sub-correction SOC; The target voltage type of the storage battery is acquired, and specifically comprises the following steps: The sleep duration of the battery management system and the current of the storage battery are acquired; In the case that the sleep duration is greater than or equal to the first preset duration, or the current is less than the first value and the first duration is greater than or equal to the second preset duration, the target voltage type of the storage battery is determined as the target static voltage, the first value is the minimum value of the first product and the first preset current, the first product is the product of the preset percentage and the current rate of the storage battery, and the first duration is the duration that the current is less than the first value; In the case that the current is less than the first value and the first duration is less than the second preset duration, the target voltage type of the storage battery is determined as the target zero-current dynamic voltage; In the case that the current is greater than or equal to the first value, the target voltage type of the storage battery is determined as the target non-zero-current dynamic voltage; The preset correction condition corresponding to the target static voltage comprises the following steps: The current single-cell voltage of the storage battery is in the non-platform region, and the current SOC accuracy is less than or equal to the first accuracy threshold, and the non-platform region is the interval with the slope greater than the preset slope in the SOC-OCV curve corresponding to the storage battery; The preset correction condition corresponding to the target zero-current dynamic voltage comprises the following steps: The current single-cell voltage of the storage battery is in the non-platform region, and the current SOC accuracy is less than or equal to the second accuracy threshold; The preset correction condition corresponding to the target non-zero-current dynamic voltage comprises the following steps: The current SOC accuracy is less than or equal to a third accuracy threshold, and an absolute value of fluctuation of a current of the energy storage battery is less than or equal to a second preset current, and a second duration greater than or equal to a third preset duration, the second duration being a duration during which the absolute value is less than or equal to the second preset current; The first accuracy threshold is greater than the second accuracy threshold, and the second accuracy threshold is greater than the third accuracy threshold.

2. The method of claim 1, wherein, The target sub-correction SOC of the energy storage battery is determined according to the target voltage type, the target working state, a current temperature of the battery management system, and a current single battery voltage, and specifically includes: In a case where the target voltage type is the target static voltage, a static OCV-SOC mapping relationship is obtained, the static OCV-SOC mapping relationship including a discharging static OCV-SOC mapping relationship and a charging static OCV-SOC mapping relationship; the discharging static OCV-SOC mapping relationship including a mapping relationship between a plurality of temperatures, a plurality of single battery voltages, and a plurality of sub-correction SOCs in the discharging state for the target static voltage; the charging static OCV-SOC mapping relationship including a mapping relationship between a plurality of the temperatures, a plurality of the single battery voltages, and a plurality of the sub-correction SOCs in the charging state for the target static voltage; the temperature corresponding to the single battery voltage one by one, and the single battery voltage corresponding to the sub-correction SOC one by one; In a case where the target working state is the charging state, a sub-correction SOC corresponding to both the current temperature and the current single battery voltage in the charging static OCV-SOC mapping relationship is determined as the target sub-correction SOC; In a case where the target working state is the discharging state, a sub-correction SOC corresponding to both the current temperature and the current single battery voltage in the discharging static OCV-SOC mapping relationship is determined as the target sub-correction SOC.

3. The method of claim 1, wherein, The target sub-correction SOC of the energy storage battery is determined according to the target voltage type, the target working state, a current temperature of the battery management system, and a current single battery voltage, and specifically includes: In a case where the target voltage type is the target zero-current dynamic voltage, a current SOC, a battery polarization decay parameter mapping relationship, a static OCV-SOC mapping relationship, and a first duration are obtained; the first duration is a duration in which a current of the energy storage battery is less than a first value; the first value is a minimum value of a first product and a first preset current, the first product being a product of a preset percentage and a current rate of the energy storage battery; the battery polarization decay parameter mapping relationship includes a battery polarization decay parameter charging mapping relationship and a battery polarization decay parameter discharging mapping relationship; the battery polarization decay parameter charging mapping relationship includes a mapping relationship between a plurality of durations, a plurality of SOCs, and a plurality of OCV conversion coefficients in the charging state; the battery polarization decay parameter discharging mapping relationship includes a mapping relationship between a plurality of the durations, a plurality of the SOCs, and a plurality of the OCV conversion coefficients in the discharging state; the duration and the SOC are in one-to-one correspondence, and the SOC and the OCV conversion coefficient are in one-to-one correspondence; the static OCV-SOC mapping relationship includes a discharging static OCV-SOC mapping relationship and a charging static OCV-SOC mapping relationship; the discharging static OCV-SOC mapping relationship includes a mapping relationship between a plurality of temperatures, a plurality of cell voltages, and a plurality of sub-correction SOCs in the discharging state for the target static voltage; the charging static OCV-SOC mapping relationship includes a mapping relationship between a plurality of the temperatures, a plurality of the cell voltages, and a plurality of the sub-correction SOCs in the charging state for the target static voltage; the temperature and the cell voltage are in one-to-one correspondence, and the cell voltage and the sub-correction SOC are in one-to-one correspondence; In a case where the target working state is the charging state, an OCV conversion coefficient corresponding to both the current SOC and the first duration in the battery polarization decay parameter charging mapping relationship is determined as a target OCV conversion coefficient; A ratio of the current cell voltage and the target OCV conversion coefficient is determined as a converted cell voltage; In a case where the target working state is the charging state, a sub-correction SOC corresponding to both the current temperature and the converted cell voltage in the charging static OCV-SOC mapping relationship is determined as the target sub-correction SOC; In a case where the target working state is the discharging state, a sub-correction SOC corresponding to both the current temperature and the converted cell voltage in the discharging static OCV-SOC mapping relationship is determined as the target sub-correction SOC.

4. The method of claim 1, wherein, The target sub-correction SOC of the energy storage battery is determined according to the target voltage type, the target working state, a current temperature of the battery management system, and a current cell voltage, and specifically includes: In a case where the target voltage type is the target non-zero-current dynamic voltage, a non-zero-current dynamic voltage mapping relationship is acquired, the non-zero-current dynamic voltage mapping relationship comprising a charging non-zero-current dynamic voltage mapping relationship and a discharging non-zero-current dynamic voltage mapping relationship; the charging non-zero-current dynamic voltage mapping relationship comprising a mapping relationship between a plurality of temperatures, a plurality of single-cell voltages and a plurality of sub-correction SOCs for the target non-zero-current dynamic voltage in the charging state; the discharging non-zero-current dynamic voltage mapping relationship comprising a mapping relationship between a plurality of temperatures, a plurality of single-cell voltages and a plurality of sub-correction SOCs for the target non-zero-current dynamic voltage in the discharging state; the temperature corresponding to the single-cell voltage one-to-one, and the single-cell voltage corresponding to the sub-correction SOC one-to-one; In a case where the target working state is the charging state, a sub-correction SOC corresponding to both the current temperature and the current single-cell voltage in the charging non-zero-current dynamic voltage mapping relationship is determined as the target sub-correction SOC; In a case where the target working state is the discharging state, a sub-correction SOC corresponding to both the current temperature and the current single-cell voltage in the discharging non-zero-current dynamic voltage mapping relationship is determined as the target sub-correction SOC.

5. The method of claim 1, wherein, The target total SOC correction accuracy of the energy storage battery is determined according to the target voltage type and the target sub-correction SOC, specifically comprising: In a case where the target voltage type is one of the target static voltage and the target zero-current dynamic voltage, a target static resting time and a static OCV-SOC accuracy mapping relationship are acquired; the target static resting time comprising one of a hibernation time of the battery management system and a first continuous time duration, the first continuous time duration being a continuous time duration during which a current of the energy storage battery is less than a first value; the first value being a minimum value of a first product and a first preset current, the first product being a product of a preset percentage and a current rate of the energy storage battery; the static OCV-SOC accuracy mapping relationship comprising a correspondence relationship among a plurality of static resting times, a plurality of sub-correction SOCs and a plurality of accuracies, the static resting time corresponding to the sub-correction SOC one-to-one, and the sub-correction SOC corresponding to the accuracy one-to-one; An accuracy corresponding to both the target static resting time and the target sub-correction SOC in the static OCV-SOC accuracy mapping relationship is determined as the target total SOC correction accuracy.

6. The method of claim 1, wherein, The target total SOC correction accuracy of the energy storage battery is determined according to the target voltage type and the target sub-correction SOC, specifically comprising: In a case where the target voltage type is the target non-zero current dynamic voltage, a non-zero current dynamic voltage SOC accuracy mapping relationship is acquired, and a current of the energy storage battery is acquired; the non-zero current dynamic voltage SOC accuracy mapping relationship includes a charging non-zero current dynamic voltage SOC accuracy mapping relationship and a discharging non-zero current dynamic voltage SOC accuracy mapping relationship; the charging non-zero current dynamic voltage SOC accuracy mapping relationship includes a mapping relationship among a plurality of currents, a plurality of sub-corrected SOCs and a plurality of accuracies in the charging state; the discharging non-zero current dynamic voltage SOC accuracy mapping relationship includes a mapping relationship among a plurality of currents, a plurality of sub-corrected SOCs and a plurality of accuracies in the discharging state; the current corresponds to the sub-corrected SOC one by one, and the sub-corrected SOC corresponds to the accuracy one by one; In a case where the target working state is the charging state, an accuracy corresponding to both the current and the target sub-corrected SOC in the charging non-zero current dynamic voltage SOC accuracy mapping relationship is determined as the target total SOC correction accuracy; In a case where the target working state is the discharging state, an accuracy corresponding to both the current and the target sub-corrected SOC in the discharging non-zero current dynamic voltage SOC accuracy mapping relationship is determined as the target total SOC correction accuracy.

7. The method of claim 6, wherein, The method further includes: In a case where a first preset updating condition is met, a plurality of maximum cell voltages corresponding to a plurality of first reference SOCs of the energy storage battery are acquired, and in a case where all the maximum cell voltages pass the verification, the charging non-zero current dynamic voltage SOC accuracy mapping relationship is updated according to all the maximum cell voltages; The first preset updating condition includes that the target total SOC correction accuracy is greater than a fourth accuracy threshold, a consistency difference of the energy storage battery is less than or equal to a consistency threshold, the battery management system is in the charging state, and an average temperature of the battery management system is greater than or equal to a first temperature threshold.

8. The method of claim 6, wherein, The method further includes: In a case where a second preset updating condition is met, a plurality of minimum cell voltages corresponding to a plurality of second reference SOCs of the energy storage battery are acquired, and in a case where all the minimum cell voltages pass the verification, the discharging non-zero current dynamic voltage SOC accuracy mapping relationship is updated according to all the minimum cell voltages; The second preset updating condition includes that the target total SOC correction accuracy is greater than a fourth accuracy threshold, a consistency difference of the energy storage battery is less than or equal to a consistency threshold, the battery management system is not in the charging state, and an average temperature of the battery management system is greater than or equal to a second temperature threshold.

9. The method of claim 1, wherein, The current SOC accuracy is acquired, and specifically includes: An initial SOC accuracy and an ampere-hour integral SOC accuracy are acquired; the initial SOC accuracy includes one of a historical SOC accuracy and an initial sub-corrected SOC accuracy; the ampere-hour integral SOC accuracy is an SOC accuracy acquired through ampere-hour integration; A difference between the initial SOC accuracy and the ampere-hour integrated SOC accuracy is determined as the current SOC accuracy.

10. The method according to any one of claims 1 to 9, characterized in that, The target SOC is determined according to the target total SOC correction accuracy, the current SOC and the target sub-correction SOC, specifically comprising: A difference between a preset value and the target total SOC correction accuracy is determined as a first accuracy difference; A product of the target total SOC correction accuracy and the target sub-correction SOC is determined as a first accuracy product; A sum of a product of the current SOC and the first accuracy difference and the first accuracy product is determined as the target SOC.

11. A charging method characterized by, The method is applied to an energy storage battery, and the method comprises: The method for determining the state of charge (SOC) according to any one of claims 1 to 10 is used to determine a target SOC of the energy storage battery; According to the target SOC, a charging strategy is determined, the charging strategy being used to represent a fast or slow degree of charging of the energy storage battery; The charging strategy is executed to realize charging of the energy storage battery.

12. A determining apparatus of a SOC, characterized in that, The device is applied to an energy storage battery, and the device comprises: A first acquisition module is configured to acquire, in a case where a battery management system is powered on, a target voltage type, a target working state, a current SOC and a current SOC accuracy of the energy storage battery, the target voltage type comprising one of a target static voltage, a target zero-current dynamic voltage and a target non-zero-current dynamic voltage; the target working state comprising one of a charging state and a discharging state; and the current SOC accuracy being used to represent a total error degree of the current SOC of the energy storage battery; A first determination module is connected to the first acquisition module and is configured to determine, in a case where a preset correction condition corresponding to the target voltage type is met, a target sub-correction SOC of the energy storage battery according to the target voltage type, the target working state, a current temperature and a current single-cell voltage of the battery management system; A second determination module is connected to the first determination module and is configured to determine a target total SOC correction accuracy of the energy storage battery according to the target voltage type and the target sub-correction SOC; the target total SOC correction accuracy being used to represent a total error degree of a target SOC of the energy storage battery; A third determination module is connected to the second determination module and is configured to determine, in a case where the target total SOC correction accuracy is greater than the current SOC accuracy, the target SOC according to the target total SOC correction accuracy, the current SOC and the target sub-correction SOC; The first acquisition module is specifically configured to: Acquire a sleep duration of the battery management system and a current current of the energy storage battery; In a case that the sleep duration is greater than or equal to a first preset duration, or the current is less than a first value and a first duration is greater than or equal to a second preset duration, the target voltage type of the energy storage battery is determined as the target static voltage; the first value is a minimum value of a first product and a first preset current, the first product is a product of a preset percentage and a current multiple of the energy storage battery, and the first duration is a duration that the current is less than the first value; In a case that the current is less than the first value and the first duration is less than the second preset duration, the target voltage type of the energy storage battery is determined as the target zero-current dynamic voltage; In a case that the current is greater than or equal to the first value, the target voltage type of the energy storage battery is determined as the target non-zero-current dynamic voltage; The preset correction condition corresponding to the target static voltage includes: The current single cell voltage of the energy storage battery is in a non-platform region, and a current SOC accuracy is less than or equal to a first accuracy threshold; the non-platform region is an interval in which a slope of an SOC-OCV curve corresponding to the energy storage battery is greater than a preset slope; The preset correction condition corresponding to the target zero-current dynamic voltage includes: The current single cell voltage of the energy storage battery is in the non-platform region, and the current SOC accuracy is less than or equal to a second accuracy threshold; The preset correction condition corresponding to the target non-zero-current dynamic voltage includes: The current SOC accuracy is less than or equal to a third accuracy threshold, and an absolute value of a current fluctuation of the energy storage battery is less than or equal to a second preset current, and a second duration is greater than or equal to a third preset duration, the second duration being a duration that the absolute value of the fluctuation is less than or equal to the second preset current; The first accuracy threshold is greater than the second accuracy threshold, and the second accuracy threshold is greater than the third accuracy threshold.

13. A charging system, characterized by The system is applied to an energy storage battery, and includes: The SOC determination device of claim 12 is used to determine a target SOC of the energy storage battery; A strategy determination device is connected to the SOC determination device, and is used to determine a charging strategy according to the target SOC, the charging strategy being used to represent a fast or slow degree of charging of the energy storage battery; An execution device is connected to the strategy determination device, and is used to execute the charging strategy to realize charging of the energy storage battery.

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