Battery SOC calculation method
By employing a segmented calculation method and weighted calculation, the problem of insufficient accuracy and real-time performance in lithium-ion battery SOC calculation is solved, achieving higher estimation accuracy and practicality, and reducing the impact of temperature, aging, and historical factors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KEBODA TECH CO LTD
- Filing Date
- 2026-02-09
- Publication Date
- 2026-05-05
AI Technical Summary
Existing methods for calculating the state of charge (SOC) of lithium-ion batteries are insufficient in terms of accuracy, real-time performance, stability, and economy, and cannot meet the requirements of practical applications.
A segmented calculation method is adopted. By correcting the initialization error during the dormant phase, and combining the ampere-hour integration method and the full charge-discharge voltage correction method, the minimum and maximum single cell SOC are calculated. The battery SOC is calculated based on weights, simplifying the model to reduce the influence of temperature, aging and historical factors.
This improves the accuracy and real-time performance of SOC estimation, reduces computational complexity, and enhances the practicality and reliability of the method.
Smart Images
Figure CN121978560A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of batteries, and more particularly to a method for calculating battery SOC (State of Charge). Background Technology
[0002] Existing methods for calculating the State of Charge (SOC) of lithium-ion batteries mainly include the open-circuit voltage method, the ampere-hour integration method, the internal resistance method, the Kalman filter method, and the neural network method. However, these methods all face some challenges in practical applications.
[0003] Open-circuit voltage method: This method estimates the state of charge (SOC) by measuring the battery's open-circuit voltage. However, the relationship between open-circuit voltage and SOC is affected by various factors such as battery temperature, aging degree, and charge / discharge history, leading to inaccurate estimation results.
[0004] Ah-hour integration method: This method estimates the state of charge (SOC) by accumulating the battery's charge and discharge currents. However, errors in the initial SOC, the accuracy of the current sensor, and accumulated errors during the integration process can all lead to deviations in the SOC estimation.
[0005] Internal resistance method: This method estimates the battery's internal resistance using the relationship between the battery's internal resistance and its state of charge (SOC). However, the battery's internal resistance is affected by various factors, such as temperature, current magnitude, and the degree of battery aging, thus limiting the accuracy of the internal resistance method.
[0006] Kalman filtering: This method establishes a state-space model of the battery and uses the Kalman filtering algorithm to estimate the state of charge (SOC). However, the accuracy of the model and the parameter settings of the filtering algorithm have a significant impact on the estimation results, and the computational complexity is high.
[0007] Neural Network Method: This method uses a neural network to learn from historical battery data and establish a mapping relationship between SOC and battery parameters. However, training a neural network requires a large amount of data, and the model's generalization ability is greatly affected by the training data.
[0008] In summary, existing methods for calculating the state of charge (SOC) of lithium-ion batteries all have varying degrees of shortcomings and cannot balance the requirements of accuracy, real-time performance, stability, and economy in practical applications. Summary of the Invention
[0009] To solve the above-mentioned technical problems, or at least partially solve them, embodiments of the present invention provide an improved battery SOC calculation method.
[0010] According to one aspect of the present invention, an embodiment of the present invention provides a battery SOC calculation method, the battery comprising a plurality of individual cells, comprising: during initialization after exiting a dormant phase, calculating the power consumption during the dormant period, and performing a dormant error correction on the lowest individual cell SOC based on the power consumption during the dormant period to obtain an initial value of the lowest individual cell SOC for the current working cycle; and performing a dormant error correction on the highest individual cell SOC based on the power consumption during the dormant period to obtain an initial value of the highest individual cell SOC for the current working cycle, wherein the lowest individual cell SOC is the SOC of the individual cell with the lowest voltage among all individual cells, and the highest individual cell SOC is the SOC of the individual cell with the highest voltage among all individual cells;
[0011] When the cell is in a discharging state and has not reached the full discharge correction stage, the lowest cell SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the lowest cell SOC obtained in the previous calculation cycle, and the highest cell SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the highest cell SOC obtained in the previous calculation cycle; when the cell is in a charging state and has not reached the full charge correction stage, the lowest cell SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the lowest cell SOC of the previous calculation cycle, and the highest cell SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the highest cell SOC of the previous calculation cycle.
[0012] When the cell is in a discharging state and has reached the full discharge correction stage, the minimum single-cell SOC of the current calculation cycle is calculated using the full discharge voltage correction method. Based on the maximum single-cell SOC obtained in the previous calculation cycle, the maximum single-cell SOC of the current calculation cycle is calculated using the ampere-hour integration method. When the cell is in a charging state and has reached the full charge correction stage, the maximum single-cell SOC of the current calculation cycle is calculated using the full charge voltage correction method. Based on the minimum single-cell SOC obtained in the previous calculation cycle, the minimum single-cell SOC of the current calculation cycle is calculated using the ampere-hour integration method.
[0013] The battery SOC for the current calculation cycle is calculated using weights based on the lowest and highest single-cell SOCs in the current calculation cycle.
[0014] Compared with existing technologies, the present invention can improve the estimation accuracy of battery SOC through segmented calculation. Attached Figure Description
[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:
[0016] Figure 1This is a schematic flowchart of a battery SOC calculation method in one embodiment of the present invention. Detailed Implementation
[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0018] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0019] Figure 1 This is a flowchart illustrating a battery SOC calculation method 100 in one embodiment of the present invention. The battery in this invention comprises multiple individual battery cells. For example... Figure 1 As shown, the battery SOC calculation method includes the following steps.
[0020] Step 110: During initialization after exiting the hibernation phase, the power consumption during hibernation is calculated, and a hibernation error correction is applied to the lowest single-cell SOC based on the power consumption during hibernation to obtain the initial value of the lowest single-cell SOC for the current working cycle; a hibernation error correction is also applied to the highest single-cell SOC based on the power consumption during hibernation to obtain the initial value of the highest single-cell SOC for the current working cycle, where the lowest single-cell SOC is the SOC of the single-cell cell with the lowest voltage among all single-cell cells, and the highest single-cell SOC is the SOC of the single-cell cell with the highest voltage among all single-cell cells. After exiting the hibernation phase, the current working cycle begins.
[0021] In one embodiment, the initial value of the lowest single-unit SOC in the current work cycle is SOC. mininit for:
[0022] SOC mininit =SOC NVMmin -∆SOC sleep ;
[0023] The initial value of the highest single-unit SOC in the current work cycle. maxinit for:
[0024] SOC maxinit =SOC NVMmax -∆SOC sleep ;
[0025] Among them, SOC mininit This is the initial value for the lowest monomeric SOC in the current work cycle; SOC NVMminThe storage value of the lowest unit SOC in the previous work cycle; SOC maxinit The initial value of the highest unit SOC in the current work cycle; SOC NVMmax The storage value of the highest single-unit SOC in the previous work cycle; ∆SOC sleep The change in SOC during the dormancy period is denoted as .
[0026] During the normal sleep phase, the controller does not completely stop all chips from working. Instead, it maintains basic detection functions with extremely low power consumption. For example, the AFE (Analog Front End) will periodically check during the sleep phase to prevent cell undervoltage, over-discharge, and other faults. When the battery SOC falls below a certain value, the controller will enter a deep sleep phase to prevent over-discharge and disable functions such as AFE checks.
[0027] Therefore, the power consumption during hibernation includes the power consumption Q during normal hibernation. sleep Power consumption Q during deep sleep deepsleep .
[0028] During normal sleep mode, an AFE (Automatic Front-End Function) monitors the circuit, recording the current and number of checks. After the MCU (Controller) wakes up, the power consumption Q during normal sleep mode is calculated using the following formula. sleep :
[0029] Q sleep =I AFE / N inspection *T sleep；
[0030] Among them, Q sleep This refers to the power consumption during normal hibernation; I AFE N is the current accumulated during inspections during the normal sleep period; inspection T represents the number of inspections during the normal dormancy period. sleep This is the normal hibernation time.
[0031] During deep sleep, AFE patrol is turned off, but all functions are disabled, with only self-discharge. At this time, the current can be considered a constant value to roughly calculate the power consumption Q during deep sleep. deepsleep :
[0032] Q deepsleep =I constant *T deepsleep
[0033] Among them: Q deepsleep Power consumption during deep sleep; I constant For deep sleep current; T deepsleep This refers to the deep sleep time.
[0034] In summary, the change in SOC during the dormancy period, ∆SOC sleep for:
[0035] ∆SOC sleep =(Q sleep +Q deepsleep ) / C bat
[0036] Where: ∆SOC sleep C represents the change in SOC during dormancy. bat The current battery capacity.
[0037] C bat =C BOL *S OH *α temp
[0038] Where: C BOL The initial capacity of the battery is a fixed value; S OH For battery health; α temp This is the temperature coefficient.
[0039] Step 120: Determine the battery charge / discharge state of the current calculation cycle. The battery charge / discharge state includes: not reaching the full discharge correction segment and not reaching the full charge correction segment; discharging state and reaching the full discharge correction segment; and charging state and reaching the full charge correction segment. The battery charge / discharge state of the current calculation cycle is one of the following: not reaching the full discharge correction segment and not reaching the full charge correction segment; discharging state and reaching the full discharge correction segment; or charging state and reaching the full charge correction segment.
[0040] If the battery charge / discharge state in the current calculation cycle has not reached the full discharge correction segment and has not reached the full charge correction segment, the process proceeds to step 130. If the battery charge / discharge state in the current calculation cycle is in the discharge state and has reached the full discharge correction segment, the process proceeds to step 140. If the battery charge / discharge state in the current calculation cycle is in the charging state and has reached the full charge correction segment, the process proceeds to step 150.
[0041] Because the ampere-hour integration method has cumulative errors and requires periodic calibration, and considering that the 12V lithium battery needs to be woken up periodically when in sleep mode and does not need to be continuously discharged during operation, the open circuit voltage method (OCV) calibration is not suitable. Full charge-discharge calibration can be used instead.
[0042] According to the charge / discharge curve of lithium batteries, the voltage changes significantly near full charge or discharge, while the voltage remains almost unchanged in the intermediate stage. Different cell compositions exhibit different voltage abrupt change points. A point to the right of the voltage abrupt change point is selected as the predetermined maximum voltage V. ChagCorrect (This is a set voltage threshold), and its corresponding SOC is SOC. ChagCorrect Select a point to the left of the voltage abrupt change point as the predetermined minimum voltage V.DischagCorrect (This is a set voltage threshold), and its corresponding SOC is SOC. DischagCorrect .
[0043] In this invention, during the discharge state, if the lowest single-cell voltage V cellmin (i.e., the voltage of the lowest single cell) is less than the predetermined minimum voltage V. DischagCorrect If the lowest single-cell SOC is less than the SOC corresponding to the predetermined lowest voltage, it is considered that the full discharge correction stage has been reached; otherwise, it is considered that the full discharge correction stage has not been reached. During charging, if the highest single-cell voltage (the voltage of the highest single-cell cell) is higher than the predetermined highest voltage V... ChagCorrect If the highest single-cell SOC is greater than the SOC corresponding to the predetermined highest voltage, then the full charge correction segment is considered to have been reached; otherwise, the full charge correction segment is considered not to have been reached.
[0044] Charging and discharging states are not mutually exclusive; a person can be in both states simultaneously.
[0045] Multiple computation cycles will be executed in the current work cycle. Each computation cycle can obtain the lowest and highest unit SOC of the current computation cycle.
[0046] Step 130: When the full-release correction segment has not been reached and the full-charge correction segment has not been reached, the lowest unit SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the lowest unit SOC obtained in the previous calculation cycle, and the highest unit SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the highest unit SOC obtained in the previous calculation cycle.
[0047] Specifically, the highest single-unit SOC in the current computation cycle is calculated using the ampere-hour integration method:
[0048] SOC maxraw =SOC maxlast +(I*dt / C bat )
[0049] Among them: SOC maxraw The highest single-unit SOC in the current computation cycle; SOC maxlast dt represents the highest single-cell SOC in the previous calculation cycle; I represents the battery current, positive for charging and negative for supplying power; dt represents the function execution period.
[0050] The minimum single-unit SOC for the current computation cycle is calculated using the ampere-hour integration method:
[0051] SOC minraw =SOC minlast +(I*dt / C bat )
[0052] Among them: SOC minrawThe lowest single-unit SOC in the current computation cycle; SOC minlast dt is the lowest single-cell SOC of the previous calculation cycle; I is the battery current, which has a direction, positive for charging and negative for supplying power; dt is the function execution period.
[0053] Step 140: When the cell is in a discharge state and reaches the full discharge correction stage, the minimum single cell SOC of the current calculation cycle is calculated using the full discharge voltage correction method. Based on the maximum single cell SOC obtained in the previous calculation cycle, the maximum single cell SOC of the current calculation cycle is calculated using the ampere-hour integration method.
[0054] Preferably, if the cell is in a discharge state and the lowest cell voltage is less than a predetermined lowest voltage but the lowest cell SOC is greater than the SOC corresponding to the predetermined lowest voltage, then the second full-discharge voltage correction method is used to calculate the lowest cell SOC of the current calculation cycle. If the cell is in a discharge state and the lowest cell SOC is less than the SOC corresponding to the predetermined lowest voltage, then the first full-discharge voltage correction method is used to calculate the lowest cell SOC of the current calculation cycle.
[0055] If the cell is in a discharge state, the minimum single-cell SOC is less than the SOC corresponding to the predetermined minimum voltage, and the minimum single-cell voltage is greater than the predetermined minimum voltage, then the SOC... minraw Responds to the lowest possible single-cell voltage change to achieve SOC DischagCorrect Lowest single cell voltage V of the battery cellmin The initial voltage value V for this stage cellminbase With the battery's full discharge voltage V fullDischag This is the final value of this stage. Based on (V) cellminbase SOC DischagCorrect ), (V fulldischag A linear interpolation curve is constructed using the two points (0, 0%), and the curve relationship is as follows:
[0056] SOC minraw =k2*V cellmin +b2
[0057] k2=SOC DischagCorrect / (V cellminbase -V fullDischag );
[0058] b2=(V fullDischag *SOC DischagCorrect ) / (V fullDischag -V cellminbase ),
[0059] Among them, SOC minraw The lowest single-unit SOC for the current computation cycle, SOC DischagCorrect V is the state of charge (SOC) corresponding to the minimum predetermined voltage. cellminbase Equal to the predetermined minimum voltage, V fullDischag V is the full discharge voltage of the battery.cellmin This is the lowest unit voltage.
[0060] In other words, the calculation formula for the first full-discharge voltage correction method is:
[0061] SOC minraw =k2*V cellmin +b2. According to V cellmin It can calculate the lowest single-unit SOC of the current computation cycle.
[0062] Preferably, the calculation formula for the second full-discharge voltage correction method is as follows:
[0063] SOC minraw =SOC minlast +N*(I*dt / C bat ),
[0064] Where N is the multiplier factor, which is related to ∆SOC, and ∆SOC = SOC during discharge. minlast -SOC DischagCorrect I represents the battery current, which is positive when charging and negative when supplying power; dt represents the function execution period.
[0065] Preferably, the multiplier factor can be queried based on ∆SOC using the following table:
[0066] ∆SOC 0.5% 1% 3% 5% 7% 10% N 1 1.2 1.6 2 2.5 3
[0067] Meanwhile, at this stage, the highest unit SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the highest unit SOC obtained in the previous calculation cycle. For the specific calculation scheme, please refer to step 130.
[0068] Step 150: When the system is in a charging state and has reached the full charge correction stage, the highest single-cell SOC of the current calculation cycle is calculated using the full charge voltage correction method. Based on the lowest single-cell SOC obtained in the previous calculation cycle, the lowest single-cell SOC of the current calculation cycle is calculated using the ampere-hour integration method.
[0069] If the cell is in a charging state and the highest single-cell voltage is higher than the predetermined highest voltage, but the highest single-cell SOC is lower than the SOC corresponding to the predetermined highest voltage, then the first full-charge voltage correction method is used to calculate the highest single-cell SOC of the current calculation cycle. If the cell is in a charging state and the highest single-cell SOC is greater than the SOC corresponding to the predetermined highest voltage, then the second full-charge voltage correction method is used to calculate the highest single-cell SOC of the current calculation cycle.
[0070] If the cell is in a charging state, the highest single-cell SOC is greater than the SOC corresponding to the predetermined highest voltage, and the highest single-cell voltage is lower than the predetermined highest voltage, then the SOC... maxraw Responding to the highest single-cell voltage change to achieve SOC ChagCorrect The highest single cell voltage of the battery Vcellmax The initial voltage value V for this stage cellmaxbase With the battery fully charged voltage V fullchag This is the final value of this stage. Since the charging current remains essentially constant when the battery is near full charge, the voltage change is essentially equivalent to the battery capacity change. Therefore, based on (V... cellmaxbase SOC ChagCorrect ), (V fullchag A linear interpolation curve is constructed from two points (100%), and the curve relationship is as follows:
[0071] SOC maxraw =k1*V cellmax +b1
[0072] k1=(100%-SOC ChagCorrect ) / (V fullchag -V cellmaxbase );
[0073] b1=((V fullchag *SOC ChagCorrect )-V cellmaxbase ) / (V fullchag -V cellmaxbase ),
[0074] Among them, SOC maxraw The highest single-unit SOC in the current computation cycle, SOC ChagCorrect V is the state of charge (SOC) corresponding to the predetermined highest voltage. cellmaxbase Equal to the predetermined maximum voltage, V fullchag For a battery to be fully charged, V cellmax This is the highest single-unit voltage.
[0075] In other words, the calculation formula for the second full-charge voltage correction method is:
[0076] SOC maxraw =k1*V cellmax +b1. According to V cellmax The highest monomeric SOC can be calculated.
[0077] Preferably, the calculation formula for the first full-charge voltage correction method is as follows:
[0078] SOC maxraw =SOC maxlast +N*(I*dt / C bat ),
[0079] Where N is the multiplier factor, which is related to ∆SOC, and during charging ∆SOC = SOC. ChagCorrect -SOC maxlast SOC maxraw The highest single-unit SOC in the current computation cycle; SOCmaxlast ΔSOC represents the highest single-cell SOC in the previous calculation cycle; I represents the battery current, positive for charging and negative for supplying power; dt represents the function execution period. Please refer to the table above for the relationship between ΔSOC and N.
[0080] Meanwhile, at this stage, the lowest unit SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the lowest unit SOC obtained in the previous calculation cycle. For the specific calculation scheme, please refer to step 130.
[0081] Step 160: Calculate the battery SOC for the current calculation cycle by weighting the lowest and highest single-cell SOCs based on the current calculation cycle.
[0082] In one embodiment, the battery SOC for the current computing cycle is:
[0083] SOC ctrl =k*SOC maxraw +(1-k)*SOC minraw ,
[0084] SOC minraw The lowest single-unit SOC in the current computation cycle, SOC maxraw The highest single-unit SOC in the current computation cycle, SOC ctrl is the battery SOC of the current calculation cycle (which can also be called the battery control SOC), and k is the proportion of the highest single cell SOC. When the discharge current is higher, k is smaller (that is, the proportion of the highest single cell SOC is lower and the proportion of the lowest single cell SOC is higher). When the charging current is lower, k is higher (that is, the proportion of the highest single cell SOC is higher and the proportion of the lowest single cell SOC is lower).
[0085] Specifically, when the current is 0.1C, k is 100%, and when the current is 0, k is 50%. Here, 1C is the charge / discharge rate unit of the battery, which is the current intensity required to fully charge or discharge the battery within 1 hour based on its rated capacity.
[0086] In one example, the following table can be used for calculation.
[0087] I(A) -6C -5C -4C -3C -2C -1C 0 0.1C 0.5C 1C 2C 3C k 0% 25% 30% 35% 40% 45% 50% 100% 80% 70% 60% 50%
[0088] Step 170: The battery SOC is smoothed and then output to prevent jumps in the output battery SOC. The output battery SOC can be displayed to the user.
[0089] In another alternative embodiment, step 170 can be omitted, and the battery SOC obtained in step 160 can be output directly.
[0090] The battery SOC calculation method in this invention can improve the accuracy and real-time performance of battery SOC estimation, reduce the influence of factors such as battery temperature, aging degree, and charge / discharge history, while reducing computational complexity and improving the practicality and reliability of the method.
[0091] The battery SOC calculation method of this invention can achieve one or more of the following beneficial effects:
[0092] Improve estimation accuracy: Segmented calculation, based on the different battery characteristics at each stage of charging and discharging, establishes a more accurate battery model, thereby improving the accuracy of SOC estimation;
[0093] Reduce influencing factors: By simplifying the model, the impact of factors such as battery temperature changes, aging degree, and charge / discharge history on the SOC estimation results is reduced;
[0094] Improved practicality and reliability: This method has low computational complexity, is easy to implement in practical applications, and has high reliability and stability.
[0095] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.
[0096] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications and variations to the above embodiments within the scope of the present invention.
Claims
1. A method for calculating the state of charge (SOC) of a battery, wherein the battery comprises multiple individual cells, characterized in that, It includes: When initializing after exiting the hibernation phase, the power consumption during hibernation is calculated, and the minimum unit SOC is corrected for hibernation error based on the power consumption during hibernation to obtain the initial value of the minimum unit SOC for the current working cycle. Based on the power consumption during the hibernation period, the highest single-cell SOC is corrected for hibernation error to obtain the initial value of the highest single-cell SOC in the current working cycle. The lowest single-cell SOC is the SOC of the single-cell cell with the lowest voltage among all single-cell cells, and the highest single-cell SOC is the SOC of the single-cell cell with the highest voltage among all single-cell cells. When the full filling correction segment has not been reached and the full charging correction segment has not been reached, the lowest unit SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the lowest unit SOC obtained in the previous calculation cycle, and the highest unit SOC of the current calculation cycle is calculated using the ampere-hour integration method based on the highest unit SOC obtained in the previous calculation cycle. When the cell is in a discharge state and reaches the full discharge correction stage, the minimum single cell SOC of the current calculation cycle is calculated using the full discharge voltage correction method. Based on the maximum single cell SOC obtained in the previous calculation cycle, the maximum single cell SOC of the current calculation cycle is calculated using the ampere-hour integration method. When the system is in a charging state and reaches the full charge correction stage, the highest single-cell SOC of the current calculation cycle is calculated using the full charge voltage correction method. Based on the lowest single-cell SOC obtained in the previous calculation cycle, the lowest single-cell SOC of the current calculation cycle is calculated using the ampere-hour integration method. The battery SOC for the current calculation cycle is obtained by weighting the lowest and highest single-cell SOCs in the current calculation cycle.
2. The battery SOC calculation method according to claim 1, characterized in that, It also includes: The battery SOC is output after smoothing and filtering. Multiple calculation cycles will be executed in the current work cycle. Each calculation cycle will calculate the lowest and highest unit SOC of the current calculation cycle.
3. The battery SOC calculation method according to claim 1, characterized in that, The battery SOC for the current calculation cycle is calculated based on the lowest and highest single-cell SOCs. SOC ctrl =k*SOC maxraw +(1-k)*SOC minraw ; in SOC minraw The lowest single-unit SOC in the current computation cycle, SOC maxraw The highest single-unit SOC in the current computation cycle, SOC ctrl is the battery SOC of the current calculation cycle, and k is the proportion of the highest single-cell SOC. The higher the discharge current, the smaller k is, and the lower the charging current, the higher k is.
4. The battery SOC calculation method according to claim 3, characterized in that, When the current is 0.1C, k is 100% and when the current is 0, k is 50%. Here, 1C is the charge / discharge rate unit of the battery, which is the current intensity required to fully charge or discharge the battery within 1 hour based on its rated capacity.
5. The battery SOC calculation method according to any one of claims 1-4, characterized in that, The initial value of the lowest monomer SOC in the current working cycle. mininit for: SOCIETY mininit =SOC NVMmin -∆SOC sleep ; The initial value of the highest single-unit SOC in the current work cycle. maxinit for: SOCIETY maxinit =SOC NVMmax -∆SOC sleep ; Among them, SOC mininit This is the initial value for the lowest monomeric SOC in the current work cycle; SOC NVMmin The storage value of the lowest unit SOC in the previous work cycle; SOC maxinit The initial value of the highest unit SOC in the current work cycle; SOC NVMmax The storage value of the highest single-unit SOC in the previous work cycle; ∆SOC sleep The change in SOC during the dormancy period is denoted as .
6. The battery SOC calculation method according to claim 5, characterized in that, The power consumption during hibernation includes the power consumption Q during normal hibernation. sleep Power consumption Q during deep sleep deepsleep , Q sleep =I AFE / N inspection *T sleep ; Among them, Q sleep This refers to the power consumption during normal hibernation; I AFE N is the current accumulated during inspections during the normal sleep period; inspection T represents the number of inspections during the normal dormancy period. sleep This is the normal hibernation time; Q deepsleep =I constant *T deepsleep ; Among them: Q deepsleep Power consumption during deep sleep; I constant For deep sleep current; T deepsleep This refers to the deep sleep time.
7. The battery SOC calculation method according to claim 6, characterized in that, ∆SOC sleep =(Q sleep +Q deepsleep ) / C bat ; Where: ∆SOC sleep C represents the change in SOC during dormancy. bat The current battery capacity. C bat =C BOL *S OH *α temp ; Where: C BOL This represents the initial capacity of the battery; S OH For battery health; α temp This is the temperature coefficient.
8. The battery SOC calculation method according to any one of claims 1-4, characterized in that, The highest single-unit SOC in the current computation cycle is calculated using the ampere-hour integration method: SOC maxraw =SOC maxlast +(I*dt / C bat ) ; Among them: SOC maxraw The highest single-unit SOC in the current computation cycle; SOC maxlast dt represents the highest single-cell SOC in the previous calculation cycle; I is the battery current, which has a direction: positive for charging and negative for supplying power; dt is the function execution period. The minimum single-unit SOC for the current computation cycle is calculated using the ampere-hour integration method: SOC minraw =SOC minlast +(I*dt / C bat ) ; Among them: SOC minraw The lowest single-unit SOC in the current computation cycle; SOC minlast This is the lowest monomeric SOC from the previous calculation cycle.
9. The battery SOC calculation method according to any one of claims 1-4, characterized in that, If the cell is in a discharge state and the lowest cell voltage is less than the predetermined lowest voltage but the lowest cell SOC is greater than the SOC corresponding to the predetermined lowest voltage, then the second full discharge voltage correction method is used to calculate the lowest cell SOC of the current calculation cycle. If the cell is in a discharge state and the minimum single cell SOC is less than the SOC corresponding to the predetermined minimum voltage, the minimum single cell SOC of the current calculation cycle is calculated using the first full discharge voltage correction method. If the cell is in a charging state and the highest single-cell voltage is higher than the predetermined highest voltage but the highest single-cell SOC is lower than the SOC corresponding to the predetermined highest voltage, then the first full charge voltage correction method is used to calculate the highest single-cell SOC of the current calculation cycle. If the cell is in a charging state and the highest single-cell SOC is greater than the SOC corresponding to the predetermined highest voltage, then the second full-charge voltage correction method is used to calculate the highest single-cell SOC of the current calculation cycle.
10. The battery SOC calculation method according to claim 9, characterized in that, The calculation formula for the second full-charge voltage correction method is: SOC maxraw =k1*V cellmax +b1; k1=(100%-SOC ChagCorrect ) / (V fullchag -V cellmaxbase ); b1=((V fullchag *SOC ChagCorrect )-V cellmaxbase ) / (V fullchag -V cellmaxbase ); Among them, SOC maxraw The highest single-unit SOC in the current computation cycle, SOC ChagCorrect V is the state of charge (SOC) corresponding to the predetermined highest voltage. cellmaxbase Equal to the predetermined maximum voltage, V fullchag For a battery to be fully charged, V cellmax This is the highest single-unit voltage; The calculation formula for the first full-charge voltage correction method is: SOC maxraw =SOC maxlast +N*(I*dt / C bat ), Where N is the multiplier factor, which is related to ∆SOC, and during charging ∆SOC = SOC. ChagCorrect -SOC maxlast SOC maxraw The highest single-unit SOC in the current computation cycle; SOC maxlast The highest single-cell SOC in the previous calculation cycle; I is the battery current, positive for charging and negative for supplying power; dt is the function execution period, C bat This represents the battery capacity at the current moment.
11. The battery SOC calculation method according to claim 9, characterized in that, The calculation formula for the first full-discharge voltage correction method is: SOC minraw =k2*V cellmin +b2; k2=SOC DischagCorrect / (V cellminbase -V fullDischag ); b2=(V fullDischag *SOC DischagCorrect ) / (V fullDischag -V cellminbase ), Among them, SOC mintraw The lowest single-unit SOC for the current computation cycle, SOC DischagCorrect V is the state of charge (SOC) corresponding to the minimum predetermined voltage. cellminbase Equal to the predetermined minimum voltage, V fullDischag V is the full discharge voltage of the battery. cellmin This is the lowest unit voltage; The calculation formula for the second full-discharge voltage correction method is: SOC minraw =SOC minlast +N*(I*dt / C bat ), Where N is the multiplier factor, which is related to ∆SOC, and ∆SOC = SOC during discharge. minlast -SOC DischagCorrect I represents the battery current, positive for charging and negative for supplying power; dt represents the function execution period, and SOC... minlast C is the lowest monomeric SOC of the previous calculation period. bat This represents the battery capacity at the current moment.