SOC calculation method, apparatus and device of lithium iron phosphate battery management system, and storage medium

Abstract

The embodiment of the invention relates to the technical field of batteries, and discloses an SOC calculation method, device and equipment for a lithium iron phosphate battery management system and a storage medium, and the method comprises the steps: recognizing that the current electric quantity value of a lithium iron phosphate battery is in a first state range; obtaining the current accumulated capacity of the lithium iron phosphate battery; and determining a real-time electric quantity correction value corresponding to the current state of the lithium iron phosphate battery according to the current accumulated capacity. The current cumulative capacity is used as the cumulative error caused when the current electric quantity value of the lithium iron phosphate battery is in the first state range, and the corrected real-time electric quantity corrected value (SOC) of the lithium iron phosphate battery is obtained by using the deviation, so that the accuracy of evaluating the SOC is improved. Therefore, the risk that the SOC drops quickly and even drops by 0% is avoided, and unnecessary potential safety hazards and power shortage are avoided.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of battery technology, and in particular to a SOC calculation method, device, equipment, and storage medium for a lithium iron phosphate battery management system. Background Art

[0002] In the field of battery technology, accurately assessing a battery pack's SOC (State of Charge) can avoid problems such as overcharging, overdischarging, lithium deposition, and sudden charge changes caused by inaccurate SOC, thereby improving battery pack safety. Accurately assessing a battery pack's SOC can also improve battery utilization. Prior art methods typically use methods such as the ampere-hour integration method and the open-circuit voltage method to assess battery pack SOC. However, the ampere-hour integration method relies on an initial SOC value. If a battery pack remains in a relatively stable plateau range for an extended period, the voltage remains virtually constant, making it impossible to calibrate and reset the initial SOC value through sudden voltage changes at high or low SOC points. This can easily lead to significant cumulative errors, resulting in low accuracy in SOC assessment. The open-circuit voltage method requires the battery pack to remain stationary, making it less practical. Furthermore, this method is significantly affected by temperature, resulting in low accuracy in SOC assessment. In summary, prior art methods for assessing battery pack SOC have low accuracy. Summary of the Invention

[0003] The object of the present invention is to provide at least a method for calculating the SOC of a lithium iron phosphate battery management system, which can at least solve the problem of low accuracy in evaluating the SOC of a battery pack and at least improve the accuracy of evaluating the SOC of a battery pack.

[0004] To solve the above technical problems, at least one embodiment of the present application provides an SOC calculation method for a lithium iron phosphate battery management system, including: identifying that the current power value of the lithium iron phosphate battery is within a first state range; obtaining the current cumulative capacity of the lithium iron phosphate battery; and determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current cumulative capacity.

[0005] At least one embodiment of the present application also provides an SOC calculation device for a lithium iron phosphate battery management system, including: an identification module for identifying that the current power value of the lithium iron phosphate battery is within a first state range; an acquisition module for acquiring the current cumulative capacity of the lithium iron phosphate battery; and a determination module for determining a real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current cumulative capacity.

[0006] At least one embodiment of the present application also provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the above-mentioned SOC calculation method of the lithium iron phosphate battery management system.

[0007] At least one embodiment of the present application further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned SOC calculation method for the lithium iron phosphate battery management system.

[0008] The SOC calculation method of the lithium iron phosphate battery management system provided in the embodiment of the present application includes: identifying that the current power value of the lithium iron phosphate battery is within the first state range; obtaining the current cumulative capacity of the lithium iron phosphate battery; and determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current cumulative capacity. The current cumulative capacity is used as the cumulative error caused when the current power value of the lithium iron phosphate battery is within the first state range, and the deviation is used to obtain the corrected real-time power correction value (SOC) of the lithium iron phosphate battery, thereby improving the accuracy of the SOC assessment. The risk of the SOC dropping rapidly, or even dropping to 0%, is avoided, so as to avoid unnecessary safety hazards and power shortages.

[0009] In some optional embodiments, the method further includes: updating the first state range using the current cumulative capacity. By continuously updating the first state range using the current cumulative capacity, the SOC estimation error caused by aging, temperature changes, etc. can be more accurately determined based on the actual battery characteristics, thereby improving the accuracy of SOC estimation.

[0010] In some optional embodiments, obtaining the current cumulative capacity of the lithium iron phosphate battery includes: obtaining a first capacity corresponding to the current stage of the lithium iron phosphate battery; and taking the sum of the first capacity and a second capacity accumulated in a previous stage as the current cumulative capacity. By accumulating the current cumulative capacity stage by stage, the actual charging and discharging behavior of the lithium iron phosphate battery can be more accurately determined, thereby improving the accuracy of obtaining the current cumulative capacity.

[0011] In some optional embodiments, the method of determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current cumulative capacity includes: determining the current hidden capacity corresponding to the current cumulative capacity based on the proportional relationship between the current cumulative capacity and the rated capacity; and determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current hidden capacity. As time goes by, all batteries will experience varying degrees of aging, causing their rated capacity to gradually decrease. By determining the current hidden capacity through the current cumulative capacity and using the current hidden capacity to evaluate the reduction in rated capacity, the obtained real-time power correction value can better reflect the actual available energy of the lithium iron phosphate battery, which is beneficial for optimizing the charge and discharge strategy of the lithium iron phosphate battery based on accurate real-time power correction values, avoiding overcharging or deep discharge, and extending the service life of the lithium iron phosphate battery.

[0012] In some optional embodiments, the method of determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current hidden capacity includes: obtaining the power correction value of the lithium iron phosphate battery in the current stage and the real-time power correction value of the previous stage; and determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the power correction value of the current stage and the real-time power correction value of the previous stage. The recursive method has certain fault tolerance and anti-interference capabilities, and can effectively improve the accuracy of the recursive results. Therefore, by determining the real-time power correction value through stage recursion, the real-time power correction value of the lithium iron phosphate battery can be determined more accurately, thereby improving the accuracy of obtaining the real-time power correction value.

[0013] In some optional embodiments, the method further includes: identifying that the current power value of the lithium iron phosphate battery is not within the first state range; clearing the current cumulative capacity of the lithium iron phosphate battery, and determining the current power value of the lithium iron phosphate battery. By periodically clearing the current cumulative capacity, the current power value of the lithium iron phosphate battery can be recalibrated, which helps eliminate measurement errors caused by long-term accumulation.

[0014] In some optional embodiments, the method further includes: identifying that the lithium iron phosphate battery is in a fully charged state; and correcting the first state range using the actual capacity of the lithium iron phosphate battery. Correcting the first state range by the charging state can recalibrate the first state range of the lithium iron phosphate battery, thereby eliminating measurement errors caused by long-term accumulation and facilitating the determination of an accurate real-time power correction value. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] One or more embodiments are exemplarily described by the figures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments.

[0016] Figure 1 This is a flow chart of a SOC calculation method for a lithium iron phosphate battery management system provided by an embodiment of the present application. Figure 1 ;

[0017] Figure 2 This is a structural diagram of a charging process and a discharging process provided by an embodiment of the present application;

[0018] Figure 3 This is a relationship curve diagram of SOC and OCV provided by an embodiment of the present application;

[0019] Figure 4 This is a structural diagram of a first state range correction provided by an embodiment of the present application;

[0020] Figure 5 This is the process of the SOC calculation method of the lithium iron phosphate battery management system provided by another embodiment of the present application Figure 2 ;

[0021] Figure 6 is a schematic diagram of an SOC calculation device for a lithium iron phosphate battery management system provided by another embodiment of the present application;

[0022] Figure 7 It is a structural diagram of an electronic device provided by another embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, each embodiment of the present application will be described in detail below with reference to the accompanying drawings. However, it will be understood by those skilled in the art that in each embodiment of the present application, many technical details are proposed to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can be implemented. The division of the following embodiments is for convenience of description and should not constitute any limitation on the specific implementation of the present application. The various embodiments can be combined and referenced with each other under the premise of no contradiction.

[0024] It should be noted that the acquisition or use of data in the embodiments of this application requires the user's consent. The relevant data can only be obtained after the user's authorization and permission, and the acquisition or use of the data complies with the provisions of relevant laws and regulations.

[0025] To facilitate understanding of the embodiments of the present application, the following describes an SOC calculation method for a lithium iron phosphate battery management system.

[0026] In the field of battery technology, accurately assessing a battery pack's SOC (State of Charge) can avoid problems such as overcharging, overdischarging, lithium deposition, and sudden charge changes caused by inaccurate SOC, thereby improving battery pack safety. Accurately assessing a battery pack's SOC can also improve battery utilization. Prior art methods typically use methods such as the ampere-hour integration method and the open-circuit voltage method to assess battery pack SOC. However, the ampere-hour integration method relies on an initial SOC value. If a battery pack remains in a relatively stable plateau range for an extended period, the voltage remains virtually constant, making it impossible to calibrate and reset the initial SOC value through sudden voltage changes at high or low SOC points. This can easily lead to significant cumulative errors, resulting in low accuracy in SOC assessment. The open-circuit voltage method requires the battery pack to remain stationary, making it less practical. Furthermore, this method is significantly affected by temperature, resulting in low accuracy in SOC assessment. In summary, prior art methods for assessing battery pack SOC have low accuracy.

[0027] In order to solve the above-mentioned technical problem of low accuracy in evaluating the SOC of a battery pack, the present invention proposes an SOC calculation method for a lithium iron phosphate battery management system. The implementation details of the SOC calculation method for the lithium iron phosphate battery management system of this embodiment are specifically described below. The following content is only the implementation details provided for ease of understanding and is not necessary for implementing this solution.

[0028] Example 1:

[0029] The SOC calculation method of the lithium iron phosphate battery management system of this embodiment can be applied to electronic devices with communication, computing and data storage capabilities. The specific process can be as follows: Figure 1 As shown, the process includes the following steps 110, 120 and 130:

[0030] Step 110 , identifying whether the current power level of the lithium iron phosphate battery is within a first state range.

[0031] Specifically, the current power value refers to the power value of the lithium iron phosphate battery at the current moment. Specifically, the power value refers to the ratio of the remaining power (usable capacity) of the lithium iron phosphate battery at the current moment to the rated capacity. For example, at the current moment, the remaining power of the lithium iron phosphate battery is 60AH, and the rated capacity of the lithium iron phosphate battery is 150AH, then the current power value is 40%.

[0032] Specifically, the first state range refers to the range of the battery level of the lithium iron phosphate battery that the user maintains for a long time when using the lithium iron phosphate battery. For example, if the user often keeps the battery level of the lithium iron phosphate battery within a range of greater than or equal to 30% and less than or equal to 80% when using the lithium iron phosphate battery, then the range of greater than or equal to 30% and less than or equal to 80% is the first state range. Figure 2 ,in, Figure 2 The upward arrow in the middle indicates the charging process, and the downward arrow indicates the discharging process. Figure 2 In the test, the power value of the lithium iron phosphate battery is in the range of greater than or equal to 30% and less than or equal to 80% during multiple charging and discharging processes. That is, when using the lithium iron phosphate battery, the user often keeps the power value of the lithium iron phosphate battery in the range of greater than or equal to 30% and less than or equal to 80%. The range of greater than or equal to 30% and less than or equal to 80% is regarded as the first state range of the lithium iron phosphate battery. The range of greater than or equal to 0% and less than 30% and the range of greater than 80% and less than or equal to 100% are both regarded as the second state range. The second state range is the range in which the power value of the lithium iron phosphate battery is not in for a long time when the user uses the lithium iron phosphate battery.

[0033] In some examples, the first state range can also be determined based on the voltage range, by obtaining the voltage range used for a long time, and determining the first state range based on the voltage range. For example, the voltage range of the lithium iron phosphate battery used by the user for a long time is greater than or equal to 3.7V and less than or equal to 4.0V. Among them, if the power value corresponding to 3.7V is 30%, and the power value corresponding to 4.0V is 80%, then the interval range greater than or equal to 30% and less than or equal to 80% is regarded as the first state range of the lithium iron phosphate battery.

[0034] Step 120: Obtain the current cumulative capacity of the lithium iron phosphate battery.

[0035] In some examples, in the aforementioned step 120, obtaining the current cumulative capacity of the lithium iron phosphate battery includes: obtaining a first capacity corresponding to the current stage of the lithium iron phosphate battery; and taking the sum of the first capacity and the second capacity accumulated in the previous stage as the current cumulative capacity.

[0036] Specifically, the current cumulative capacity refers to the total charge capacity and discharge capacity of the lithium iron phosphate battery from the initial moment when the battery level is within the first state range to the current moment when the battery level continues to be within the first state range. Specifically, the charge capacity and the discharge capacity are both values ​​greater than zero.

[0037] Specifically, the current stage may be a charging stage or a discharging stage, and the power value at each moment in the current stage is within the first state range.

[0038] Specifically, the previous stage is a stage consisting of multiple moments less than the initial moment of the current stage at which the corresponding power values ​​are within the first state range. Specifically, the previous stage is a stage with the initial moment of the current stage as the end moment and the next moment whose corresponding power value is not within the first state range, is closest to the end moment, and is less than the end moment as the start moment. The previous stage can be at least one charging stage, the previous stage can also be at least one discharging stage, or the previous stage can also be at least one charging stage and at least one discharging stage.

[0039] Specifically, the second capacity refers to the total capacity of the charge capacity and the discharge capacity in the previous stage.

[0040] In some examples, the previous stage may or may not exist. If the battery level at the moment before the start of the current stage is not within the first state range, the previous stage is deemed not to exist. If the battery level at the moment before the start of the current stage is within the first state range, the previous stage is deemed not to exist. When the previous stage does not exist, the second capacity is 0.

[0041] Exemplarily, if the current stage is the charging stage, the charging capacity of the charging stage is obtained and the charging capacity is used as the first capacity; if the power value at the moment before the start moment of the current stage is not in the first state range, it is deemed that the previous stage does not exist, and the second capacity is 0; the first capacity is used as the current cumulative capacity.

[0042] If the current stage is the charging stage, the charging capacity of the charging stage is obtained and the charging capacity is used as the first capacity; if the power value at the moment before the start time of the current stage is in the first state range, the second capacity accumulated in the previous stage is obtained and is deemed to exist in the previous stage, and the sum of the first capacity and the second capacity is used as the current accumulated capacity.

[0043] In some examples, obtaining the first capacity corresponding to the current stage of the lithium iron phosphate battery includes: obtaining the first capacity corresponding to the current stage of the lithium iron phosphate battery using an integral method, wherein the unit of the first capacity is . A specific implementation process of obtaining the first capacity corresponding to the current stage of the lithium iron phosphate battery using an integral method can be found in the prior art and is not further described here.

[0044] It can be seen from this that by accumulating the current cumulative capacity stage by stage, the actual charging and discharging behavior of the lithium iron phosphate battery can be determined more accurately, thereby improving the accuracy of obtaining the current cumulative capacity.

[0045] Step 130: Determine a real-time power correction value corresponding to the current state of the lithium iron phosphate battery according to the current accumulated capacity.

[0046] Specifically, the real-time power correction value refers to the ratio of the remaining power of the lithium iron phosphate battery at that moment to the rated capacity, also known as SOC (State of Charge), where the remaining power refers to the difference between the remaining capacity displayed by the lithium iron phosphate battery and the current cumulative capacity.

[0047] In some examples, in the aforementioned step 130, determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current cumulative capacity includes the following steps 131-132:

[0048] Step 131, determining a current hidden capacity corresponding to the current cumulative capacity based on a proportional relationship between the current cumulative capacity and the rated capacity;

[0049] Specifically, the rated capacity refers to the standard capacity specified by the manufacturer of the lithium iron phosphate battery.

[0050] Specifically, the current hidden capacity refers to the unavailable power that is not measured due to measurement limitations.

[0051] In some examples, based on the proportional relationship between the current cumulative capacity and the rated capacity, determining the current hidden capacity corresponding to the current cumulative capacity includes: obtaining the hidden capacity corresponding to the proportional relationship between the cumulative capacity and the rated capacity from a preset capacity table, and using the hidden capacity as the current hidden capacity corresponding to the current cumulative capacity. The preset capacity table includes the proportional relationship between the cumulative capacity and the rated capacity, and the corresponding relationship with the hidden capacity. The corresponding relationship can be obtained through testing based on a large amount of experimental data, and the unknown corresponding relationship can be estimated based on the known corresponding relationship using a linear interpolation lookup table to obtain a preset capacity table containing a large number of corresponding relationships. It can be seen from this that

[0052] Exemplarily, the specific content of estimating the unknown corresponding relationship based on the known corresponding relationship using linear interpolation lookup table is: if the rated capacity of the battery pack (lithium iron phosphate battery) is 150AH, the cumulative capacity (charging capacity + discharging capacity) reaches 300AH, the proportional relationship is 2, and the corresponding hidden capacity is 1%*rated capacity. When the cumulative capacity (charging capacity + discharging capacity) is 600AH, the proportional relationship is 4, and the corresponding hidden capacity is 2%*rated capacity. Similarly, based on the known corresponding relationship of 2 corresponding to 1%*rated capacity and the corresponding relationship of 4 corresponding to 2%*rated capacity, it is inferred that when the cumulative capacity (charging capacity + discharging capacity) reaches N*300AH, the corresponding hidden capacity is N*1%*rated capacity, where * refers to multiplication.

[0053] In some examples, based on the proportional relationship between the current cumulative capacity and the rated capacity, determining the current hidden capacity corresponding to the current cumulative capacity includes: obtaining a preset coefficient; obtaining the ratio of the cumulative capacity to the rated capacity, and taking the product of the preset coefficient, the ratio, and the rated capacity as the current hidden capacity corresponding to the current cumulative capacity, wherein the preset coefficient is obtained through experiments based on a large amount of experimental data. In this solution, the preset coefficient is 0.5 based on a large amount of experimental data, but is not limited to the preset coefficient of 0.5. It can be seen from this that

[0054] Step 132: Determine the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current hidden capacity.

[0055] It should be understood that if multiple charge and discharge cycles are performed within the first state range, the accumulated current cumulative capacity will gradually increase, thereby causing the error of the detected current power value to become larger. Therefore, in order to obtain an accurate power value, this solution corrects the current power value detected corresponding to the current state by the current hidden capacity, and obtains the real-time power correction value corresponding to the current state. The real-time power correction value is used to accurately reflect the true power value corresponding to the current state of the lithium iron phosphate battery. In some examples, in the aforementioned step 132, based on the current hidden capacity, the real-time power correction value corresponding to the current state of the lithium iron phosphate battery is determined, including: using the ratio of the current hidden capacity to the rated capacity as the current power correction value corresponding to the current hidden capacity, using the power value corresponding to the previous moment of the start time of the previous stage as the initial power value; and using the difference between the initial power value and the current power correction value as the real-time power correction value corresponding to the current state. Exemplarily, if the first state range is greater than or equal to 30% and less than or equal to 80%, the power value corresponding to the starting moment of the previous stage is 80%, and the power value corresponding to the previous moment before the starting moment of the previous stage is 81%, then the power value of 81% is used as the initial power value. If the current hidden capacity corresponding to the current state is 2%*rated capacity, the current power correction amount is 2%, and the real-time power correction value corresponding to the current state is 79%.

[0056] Specifically, the current power correction amount refers to the ratio of the current hidden capacity to the rated capacity corresponding to the current moment.

[0057] In some examples, in the aforementioned step 132, determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the current hidden capacity includes: obtaining the power correction value of the lithium iron phosphate battery in the current stage and the real-time power correction value of the previous stage; and determining the real-time power correction value corresponding to the current state of the lithium iron phosphate battery based on the power correction value of the current stage and the real-time power correction value of the previous stage. It can be seen that the recursive method has certain fault tolerance and anti-interference capabilities, and can effectively improve the accuracy of the recursive result. Therefore, by determining the real-time power correction value through stage recursion, the real-time power correction value of the lithium iron phosphate battery can be determined more accurately, thereby improving the accuracy of obtaining the real-time power correction value.

[0058] Specifically, the power correction amount refers to the ratio of the hidden capacity corresponding to the first capacity in the current stage to the rated capacity. For example, if the ratio of the hidden capacity corresponding to the first capacity to the rated capacity is 1%, the power correction amount is 1%.

[0059] Specifically, the previous stage refers to the stage before the current stage, and the real-time power correction value of the previous stage refers to the real-time power correction value corresponding to the end time of the previous stage. For example, if the real-time power correction value corresponding to the end time of the previous stage is 80%, then the real-time power correction value of the previous stage is 80%.

[0060] In some examples, determining the real-time charge correction value corresponding to the current state of the lithium iron phosphate battery based on the charge correction value of the current stage and the real-time charge correction value of the previous stage includes: using the difference between the real-time charge correction value of the previous stage and the charge correction value of the current stage as the real-time charge correction value corresponding to the current state of the lithium iron phosphate battery. For example, if the real-time charge correction value of the previous stage is 80% and the charge correction value is 1%, then the real-time charge correction value corresponding to the current state is 79%.

[0061] As can be seen, all batteries experience varying degrees of aging over time, resulting in a gradual reduction in their rated capacity. By determining the current hidden capacity from the current accumulated capacity and using it to estimate the reduction in rated capacity, the real-time charge correction value obtained better reflects the true available energy of the lithium iron phosphate battery. This helps optimize the charge and discharge strategies of the lithium iron phosphate battery based on accurate real-time charge correction values, avoiding overcharging or deep discharge and extending the battery's service life.

[0062] In some examples, the method further includes: identifying that the current charge value of the lithium iron phosphate battery is not within the first state range; clearing the current cumulative capacity of the lithium iron phosphate battery, and determining the current charge value of the lithium iron phosphate battery. Thus, by periodically clearing the current cumulative capacity, the current charge value of the lithium iron phosphate battery can be recalibrated, which helps eliminate measurement errors caused by long-term accumulation.

[0063] Specifically, the current power value refers to the ratio of the remaining power of the lithium iron phosphate battery at the current moment to the rated capacity, also known as SOC (State of Charge), wherein the remaining power refers to the sum of the remaining capacity displayed by the lithium iron phosphate battery and the current cumulative capacity. Exemplarily, if the first state range is greater than or equal to 29% and less than or equal to 80% of the first state range, and the current power value is 28%, then the current cumulative capacity corresponding to the current moment is 0, and the current power value is 28%.

[0064] It should be understood that if multiple charge and discharge cycles are performed within the first state range of greater than or equal to 30% and less than or equal to 80%, the accumulated current cumulative capacity will gradually increase. In the long run, as the current cumulative capacity increases, if the lithium iron phosphate battery is continuously kept in the first state range of greater than or equal to 30% and less than or equal to 80% with a shallow depth of discharge, the risk of lithium deposition in the lithium iron phosphate battery will increase. Figure 3When the lithium iron phosphate battery is in the first state range of greater than or equal to 30% and less than or equal to 80%, its voltage variation is small, that is, the depth of discharge is shallow. In the non-first state range, its voltage variation is large. Therefore, to solve this problem, this solution adjusts the first state range based on the current cumulative capacity. Because overcharging is more harmful than overdischarging, this solution adjusts the lower limit of the first state range to take advantage of the occasional deeper depth of discharge and avoid the risk of lithium deposition in the lithium iron phosphate battery. In some examples, the method further includes: updating the first state range using the current cumulative capacity. Specifically, based on a preset capacity table, a power adjustment value corresponding to the current cumulative capacity is determined, and the difference between the initial unadjusted starting value of the first state range and the power adjustment value is used as the new starting value. The new starting value is used as the starting value of the first state range to obtain an updated first state range. The preset capacity table includes a correspondence between cumulative capacity and power adjustment value. The correspondence in the preset capacity table is experimentally obtained based on a large amount of experimental data. For example, if the first state range is greater than or equal to 30% and less than or equal to 80%, and the power adjustment value is 2%, then the updated first state range is greater than or equal to 28% and less than or equal to 80%. This shows that by continuously updating the first state range using the current accumulated capacity, it can be closer to the actual current characteristics of the battery, reducing SOC estimation errors caused by aging, temperature changes, etc., and improving the accuracy of SOC acquisition.

[0065] In some examples, the method further includes repeatedly executing to identify whether the current charge value of the lithium iron phosphate battery is within the updated first state range, and if so, executing the aforementioned step 120, and executing based on a preset capacity table, determining the charge adjustment value corresponding to the current cumulative capacity, and using the difference between the initial unadjusted starting value of the first state range and the charge adjustment value as the new starting value, and using the new starting value as the starting value (lower limit value) of the first state range to obtain the updated first state range, and stopping execution until the current charge value of the lithium iron phosphate battery is no longer within the updated first state range.

[0066] Specifically, the initially unadjusted first state range refers to the first state range corresponding to when the current cumulative capacity is 0. When the current cumulative capacity is 0, the power adjustment value corresponding to the current cumulative capacity is 0.

[0067] For example, see Figure 4 , Figure 4The interval between 30% and 80% represents the first state range corresponding to the current cumulative capacity of the lithium iron phosphate battery when it is 0. When the lithium iron phosphate battery has no cumulative capacity, its corresponding first state range is greater than or equal to 30% and less than or equal to 80%. Within the first state range of greater than or equal to 30% and less than or equal to 80%, after charging and discharging in time period 1 (i.e., at each moment in time period 1, the current power value of the lithium iron phosphate battery is within the first state range), the lithium iron phosphate battery has a first current cumulative capacity (the first current cumulative capacity is the total cumulative capacity of time period 1). At this time, to avoid the risk of lithium deposition, it is necessary to adjust the lower limit of the first state range to enable occasional deep discharge of the lithium iron phosphate battery. If the power adjustment value corresponding to the first current cumulative capacity is 1%, then the updated first state range is greater than or equal to 29% and less than or equal to 80%. If each moment is in time period 2 after time period 1, and the lithium iron phosphate battery is charged and discharged again in time period 2, and at each moment in time period 2, the current power value of the lithium iron phosphate battery is within the updated first state range of greater than or equal to 29% and less than or equal to 80%, then the power adjustment value corresponding to the second current cumulative capacity of time period 2 is determined to be 2%. At this time, the updated first state range is greater than or equal to 28% and less than or equal to 80%, where the second current cumulative capacity refers to the total accumulated capacity of time periods 1 and 2. Similarly, after multiple charging and discharging in the first state range, the lower limit of the first state range is continuously adjusted to greater than or equal to 1% and less than or equal to 80%. If the current power value of the lithium iron phosphate battery continues to be within the first state range of greater than or equal to 1% and less than or equal to 80%, the current cumulative capacity increases again, and the lower limit of the first state range is adjusted again until it is adjusted to the first state range of greater than or equal to 0% and less than or equal to 80%. Among them, if the current cumulative capacity is greater than or equal to the preset threshold, the power adjustment value corresponding to the current cumulative capacity is the same, and is equal to the power adjustment value corresponding to when the current cumulative capacity is equal to the preset threshold, wherein the power adjustment value corresponding to the preset threshold is equal to the starting value (lower limit value) of the first state range that has not been initially adjusted.

[0068] In some examples, the method further includes: identifying that the lithium iron phosphate battery is in a fully charged state; and correcting the first state range using the actual capacity of the lithium iron phosphate battery. Thus, by correcting the first state range using the charging state, the first state range of the lithium iron phosphate battery can be recalibrated, which helps eliminate measurement errors caused by long-term accumulation and facilitates determining an accurate real-time power correction value.

[0069] Specifically, when the lithium iron phosphate battery is fully charged, the actual capacity is approximately equal to the rated capacity.

[0070] In some examples, using the actual capacity of the lithium iron phosphate battery to correct the first state range includes: restoring the first state range to the first state range corresponding to the fully charged state. For example, if the first state range corresponding to the fully charged lithium iron phosphate battery is greater than or equal to 30% and less than or equal to 80%, and the first state range of the lithium iron phosphate battery before being fully charged is greater than or equal to 10% and less than or equal to 80%, when the lithium iron phosphate battery is fully charged, its first state range is restored to the range greater than or equal to 30% and less than or equal to 80%.

[0071] For a clearer understanding of this solution, please refer to Figure 5 , obtain a first state range, determine whether the current power value of the lithium iron phosphate battery is within the first state range, and if so, obtain the current cumulative capacity of the lithium iron phosphate battery, determine the real-time power correction value corresponding to the current state of the lithium iron phosphate battery according to the current cumulative capacity, and use the current cumulative capacity to update the first state range, and again determine whether the current power value of the lithium iron phosphate battery is within the first state range (updated first state range), if not, clear the current cumulative capacity, and determine the real-time power correction value corresponding to the current state of the lithium iron phosphate battery according to the current cumulative capacity, and use the current cumulative capacity to update the first state range.

[0072] In summary, this solution identifies that the current charge value of the lithium iron phosphate battery is within the first state range; obtains the current cumulative capacity of the lithium iron phosphate battery; and determines the real-time charge correction value corresponding to the current state of the lithium iron phosphate battery based on the current cumulative capacity. The current cumulative capacity is used as the cumulative error caused by the current charge value of the lithium iron phosphate battery being within the first state range, and this deviation is used to obtain the corrected real-time charge correction value (SOC) of the lithium iron phosphate battery, thereby improving the accuracy of SOC assessment. The risk of the SOC dropping rapidly, or even dropping to 0%, is avoided, so as to avoid unnecessary safety hazards and power shortages.

[0073] Example 2:

[0074] Another embodiment of the present application relates to an SOC calculation device for a lithium iron phosphate battery management system. The implementation details of the SOC calculation device for the lithium iron phosphate battery management system of this embodiment are specifically described below. The following content is only for the convenience of understanding the implementation details provided and is not necessary for the implementation of this solution. The schematic diagram of the SOC calculation device 60 of the lithium iron phosphate battery management system of this embodiment can be as follows Figure 6 As shown, it includes an identification module 601 , an acquisition module 602 and a determination module 603 .

[0075] An identification module 601 is configured to identify whether a current power level of the lithium iron phosphate battery is within a first state range;

[0076] An acquisition module 602 is configured to acquire the current cumulative capacity of the lithium iron phosphate battery;

[0077] The determination module 603 is configured to determine a real-time power correction value corresponding to the current state of the lithium iron phosphate battery according to the current accumulated capacity.

[0078] It is worth mentioning that all modules involved in this embodiment are logical modules. In actual applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, to highlight the innovation of this application, this embodiment does not include units that are not closely related to solving the technical problem proposed by this application. However, this does not mean that other units do not exist in this embodiment.

[0079] Example 3:

[0080] Another embodiment of the present application relates to an electronic device, such as Figure 7 As shown, it includes: at least one processor 901; and a memory 902 that is communicatively connected to the at least one processor 901; wherein the memory 902 stores instructions that can be executed by the at least one processor 901, and the instructions are executed by the at least one processor 901 so that the at least one processor 901 can execute the SOC calculation method of the lithium iron phosphate battery management system in the above-mentioned embodiments.

[0081] The memory and processor are connected using a bus, which can include any number of interconnected buses and bridges. The bus connects various circuits of one or more processors and memories. The bus can also connect various other circuits such as peripheral devices, voltage regulators, and power management circuits. These are all well known in the art and are therefore not described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single component or multiple components, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over a wireless medium via an antenna. Furthermore, the antenna receives data and transmits it to the processor.

[0082] The processor is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory can be used to store data used by the processor when performing operations.

[0083] Example 4:

[0084] Another embodiment of the present application relates to a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

[0085] That is, those skilled in the art will understand that all or part of the steps in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a program, which is stored in a storage medium and includes a number of instructions for causing a device (which may be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, etc., various media that can store program code.

[0086] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present application, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.

Claims

1. A SOC calculation method for a lithium iron phosphate battery management system, characterized in that: include: Identifying that a current power level of the lithium iron phosphate battery is within a first state range; Obtaining the current cumulative capacity of the lithium iron phosphate battery; A real-time power correction value corresponding to the current state of the lithium iron phosphate battery is determined according to the current accumulated capacity.

2. The SOC calculation method of the lithium iron phosphate battery management system according to claim 1, characterized in that: Also includes: The first state range is updated using the current accumulated capacity.

3. The SOC calculation method of the lithium iron phosphate battery management system according to claim 1, characterized in that: The obtaining of the current cumulative capacity of the lithium iron phosphate battery includes: Obtaining a first capacity corresponding to the current stage of the lithium iron phosphate battery; The sum of the first capacity and the second capacity accumulated in the previous stage is used as the current accumulated capacity.

4. The SOC calculation method of the lithium iron phosphate battery management system according to claim 1, characterized in that: The determining, based on the current cumulative capacity, a real-time power correction value corresponding to the current state of the lithium iron phosphate battery includes: Determining a current hidden capacity corresponding to the current cumulative capacity based on a proportional relationship between the current cumulative capacity and the rated capacity; Based on the current hidden capacity, the real-time power correction value corresponding to the current state of the lithium iron phosphate battery is determined.

5. The SOC calculation method of the lithium iron phosphate battery management system according to claim 4, characterized in that: The determining, based on the current hidden capacity, the real-time power correction value corresponding to the current state of the lithium iron phosphate battery includes: Obtaining a current power correction value of the lithium iron phosphate battery and a real-time power correction value of the previous power correction value; The real-time power correction value corresponding to the current state of the lithium iron phosphate battery is determined based on the power correction value of the current stage and the real-time power correction value of the previous stage.

6. The SOC calculation method of the lithium iron phosphate battery management system according to claim 1, characterized in that: Also includes: Identifying that a current power level of the lithium iron phosphate battery is not within the first state range; The current accumulated capacity of the lithium iron phosphate battery is reset to zero, and the current power value of the lithium iron phosphate battery is determined.

7. The SOC calculation method of the lithium iron phosphate battery management system according to claim 6, characterized in that: Also includes: Identifying that the lithium iron phosphate battery is in a fully charged state; The first state range is corrected using the actual capacity of the lithium iron phosphate battery.

8. A SOC calculation device for a lithium iron phosphate battery management system, characterized in that: include: an identification module, configured to identify that a current power level of the lithium iron phosphate battery is within a first state range; An acquisition module, configured to acquire the current cumulative capacity of the lithium iron phosphate battery; The determination module is used to determine the real-time power correction value corresponding to the current state of the lithium iron phosphate battery according to the current cumulative capacity.

9. An electronic device, characterized in that: include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the SOC calculation method of the lithium iron phosphate battery management system as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the SOC calculation method of the lithium iron phosphate battery management system according to any one of claims 1 to 7 is implemented.

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