Sop correction method, battery management system, and computer readable storage medium

Abstract

The application discloses a SOP correction method, a battery management system and a computer readable storage medium. The method comprises the following steps: obtaining a current first SOP value; wherein the SOP value represents a battery power state; when the current discharge current is less than a reference discharge current, the current minimum single battery voltage is less than a reference minimum single battery voltage, and the current single battery voltage difference is less than a reference single battery voltage difference, the first SOP value is corrected to a set second SOP value, and the second SOP value is less than the first SOP value; wherein the current single battery voltage difference is the difference between the current maximum single battery voltage and the current minimum single battery voltage, the reference single battery voltage difference is the difference between the reference maximum single battery voltage and the reference minimum single battery voltage, and the reference discharge current, the reference maximum single battery voltage and the reference minimum single battery voltage are determined by the first SOP value. In the foregoing manner, adaptive calibration of the SOP can be achieved.

Description

Technical Field

[0001] This application relates to the field of battery management technology, and in particular to a SOP correction method, a battery management system, and a computer-readable storage medium. Background Technology

[0002] A battery pack typically consists of battery modules, a thermal management system, a battery management system (BMS), an electrical system, and structural components. A battery module is composed of multiple battery cells (individual cells). Generally, the BMS's estimation of the battery's SOP (State of Power) is interrelated with its estimations of SOC (State of Charge) and SOH (State of Health), but the estimations of SOC and SOH are not affected by SOP.

[0003] If the battery system is not fully charged for a long time or operates in the uncorrected SOC range for an extended period, the SOC will not be calibrated and corrected. This will lead to a gradual accumulation of errors due to factors such as current sensor acquisition errors, time integration errors, the effect of temperature on capacity, self-discharge, and current rate. Furthermore, the SOH (Symptom Balance) will also differ from the actual test conditions due to variations in the battery system's operating conditions and storage temperature. This difference will cause discrepancies between the cycle life parameters written into the BMS and the actual cycle life, affecting the SOH estimation error. These two errors directly lead to errors in SOP (Sum Opening) estimation. If the estimated SOP is higher than the actual SOP, the vehicle will operate at an excessively high allowable discharge current, causing the voltage to drop or even triggering an undervoltage alarm, affecting normal vehicle operation and, in severe cases, even causing the vehicle to break down and become immobile. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a SOP correction method, a battery management system, and a computer-readable storage medium, which enable adaptive calibration of the SOP.

[0005] One technical solution adopted in this application is: providing a SOP correction method applied to a battery management system. The SOP correction method includes: obtaining a current first SOP value; wherein the SOP value represents the battery power state; when the current discharge current is less than a reference discharge current, and the current minimum voltage of a single cell is less than the minimum voltage of a reference single cell, and the current voltage difference between single cells is less than the voltage difference between a reference single cell, the first SOP value is corrected to a set second SOP value, wherein the second SOP value is less than the first SOP value; wherein the current voltage difference between single cells is the difference between the current maximum voltage of a single cell and the current minimum voltage of a single cell, the reference voltage difference between single cells is the difference between the maximum voltage of a reference single cell and the minimum voltage of a reference single cell, and the reference discharge current, the maximum voltage of a reference single cell, and the minimum voltage of a reference single cell are determined by the first SOP value.

[0006] In one embodiment, obtaining the current first SOP value includes: obtaining the current SOC value and the current temperature value; wherein the SOC value represents the battery charge state; based on a pre-established SOC-temperature-SOP table, looking up the table to obtain the SOP lookup value corresponding to the current SOC value and the current temperature value; and determining the current first SOP value based on the SOP lookup value.

[0007] In one embodiment, determining the current first SOP value based on the SOP lookup table value includes: determining the current first SOP value based on the SOP lookup table value and the current SOH value; wherein the SOH value represents the battery health status.

[0008] In one embodiment, correcting a first SOP value to a set second SOP value, wherein the second SOP value is less than the first SOP value, includes: correcting the current SOC value to the next lower level SOC value at the same temperature according to the SOC-temperature-SOP table, and using the corrected first SOP value as the SOP value corresponding to the next lower level SOC value at the same temperature as the second SOP value.

[0009] In one embodiment, the method further includes: based on a pre-established SOP-cell voltage range table, looking up the table to obtain the maximum and minimum reference cell voltage values ​​corresponding to the first SOP value; and determining the reference cell voltage difference based on the difference between the maximum and minimum reference cell voltage values.

[0010] In one embodiment, the method further includes: counting the number of SOP value corrections; when the number of SOP value corrections exceeds a set threshold, correcting the current SOH value; wherein the SOH value represents the battery health status.

[0011] In one embodiment, counting the number of SOP value corrections includes: during the discharge process after the battery is fully charged, when an SOP value correction is triggered, the number of SOP value corrections is incremented by 1, and the number of SOP value corrections is accumulated at most once during a single discharge process.

[0012] In one embodiment, correcting the current SOH value includes: obtaining a SOC correction value when the battery meets the static correction conditions; determining the actual battery capacity based on the SOC correction value; and determining a SOH correction value based on the actual battery capacity as the current SOH value.

[0013] The SOP correction method provided in this application includes: obtaining a current first SOP value; wherein the SOP value represents the battery power state; when the current discharge current is less than a reference discharge current, and the current minimum voltage of a single cell is less than the minimum voltage of a reference single cell, and the current voltage difference between single cells is less than the voltage difference between a reference single cell, the first SOP value is corrected to a set second SOP value, wherein the second SOP value is less than the first SOP value; wherein the current voltage difference between single cells is the difference between the current maximum voltage of a single cell and the current minimum voltage of a single cell, the reference voltage difference between single cells is the difference between the maximum voltage of a reference single cell and the minimum voltage of a reference single cell, and the reference discharge current, the maximum voltage of a reference single cell, and the minimum voltage of a reference single cell are determined by the first SOP value. In this way, when the actual SOH and SOC of an electric vehicle battery system differ from the SOH and SOC calibration parameters obtained from the original test data due to the actual usage environment and operating conditions, the original calibration parameters can no longer accurately support the calibration of the actual battery system's SOH and SOC. At this time, the voltage characteristics generated by the use of the current SOP calibration parameters can reflect whether there is a large error in SOC and SOH, thereby achieving adaptive calibration of SOC, and then adaptive calibration of SOP, so that the battery system can work on a suitable voltage platform. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart illustrating the first embodiment of the SOP modification method provided in this application;

[0016] Figure 2 yes Figure 1 A flowchart illustrating an embodiment of step 11;

[0017] Figure 3 This is a flowchart illustrating the second embodiment of the SOP modification method provided in this application;

[0018] Figure 4 yes Figure 3 A flowchart illustrating an embodiment of step 34;

[0019] Figure 5 This is a schematic diagram of the structure of an embodiment of the battery management system provided in this application;

[0020] Figure 6 This is a schematic diagram of an embodiment of the computer-readable storage medium provided in this application. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0024] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0025] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0026] See Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the SOP modification method provided in this application. The method includes:

[0027] Step 11: Obtain the current first SOP value.

[0028] The SOP value represents the battery's state of power, which is the maximum allowable power value during charging and discharging. This power value can also be expressed as a current value.

[0029] In one embodiment, SOP is the maximum allowable charge / discharge current value of the current battery system, obtained by looking up tables and multiplying by a scaling factor (SOH) based on the current battery system temperature (maximum and minimum temperature values), SOC value, and SOH value. (The allowable current is obtained by looking up tables based on the maximum temperature-SOC and minimum temperature-SOC values ​​respectively, taking the smaller of the two, and then multiplying by SOH%.)

[0030] Optionally, such as Figure 2 As shown, Figure 2 yes Figure 1 A flowchart of an embodiment of step 11 is shown. Step 11 may include:

[0031] Step 111: Obtain the current SOC value and the current temperature value.

[0032] The State of Charge (SOC) value represents the battery's state of charge. Generally, the SOC value is estimated by integrating the charge and discharge currents detected under historical and current battery system operating conditions, and by using certain correction methods under specific settings.

[0033] Step 112: Based on the pre-established SOC-Temperature-SOP table, look up the table to obtain the current SCO value and the corresponding SOP lookup value for the current temperature value.

[0034] Optionally, the following is a schematic diagram of a SOC-Temperature-SOP table in an embodiment. The horizontal axis represents temperature, the vertical axis represents SOC, and the cells with no data entered for SOC and temperature represent SOP. This is because the corresponding SOP lookup value can be determined by looking up the table based on the current SCO value and the current temperature value.

[0035]

[0036]

[0037] Step 113: Determine the current first SOP value based on the SOP lookup table value.

[0038] Specifically, the current first SOP value is determined based on the SOP lookup table value and the current SOH value.

[0039] The State of Health (SOH) value indicates the battery's health status. Generally, the SOH value is estimated based on parameters such as the number of charge / discharge cycles, temperature capacity retention, and calendar life.

[0040] Specifically, the first SOP value = SOP lookup table value × current SOH value (%).

[0041] Step 12: When the current discharge current is less than the reference discharge current, the current minimum single cell voltage is less than the reference minimum single cell voltage, and the current single cell voltage difference is less than the reference single cell voltage difference, the first SOP value is corrected to the set second SOP value, where the second SOP value is less than the first SOP value.

[0042] Among them, the current single cell voltage difference is the difference between the current single cell voltage maximum value and the current single cell voltage minimum value, the reference single cell voltage difference is the difference between the reference single cell voltage maximum value and the reference single cell voltage minimum value, and the reference discharge current, the reference single cell voltage maximum value, and the reference single cell voltage minimum value are determined by the first SOP value.

[0043] Optionally, in this embodiment, the first SOP value can be represented by a current value. Therefore, the reference discharge current is the first SOP value, and it is only necessary to determine whether the current discharge current is less than the first SOP value. In other embodiments, if the first SOP value is not represented by a current value, it is converted to the corresponding current value as the reference discharge current.

[0044] Understandably, under the same temperature conditions, the lower the State of Charge (SOC), the smaller the permissible State of Operation (SOP). One characteristic for judging the accuracy of the SOP is that when the battery system discharges at the current SOP value, the resulting voltage is within a reasonable range and does not trigger undervoltage. We consider the current SOP value to be accurate and appropriate. Therefore, we can calibrate through testing to derive the lower limit of the reasonable voltage corresponding to the current SOP value: Cell_V_L, the upper limit: Cell_V_H, and the voltage difference Cell_V_delta.

[0045] Therefore, the above method may further include: based on a pre-established SOP-cell voltage range table, looking up the table to obtain the maximum reference cell voltage Cell_V_H and the minimum reference cell voltage Cell_V_L corresponding to the first SOP value; and determining the reference cell voltage difference Cell_V_delta based on the difference between the maximum reference cell voltage Cell_V_H and the minimum reference cell voltage Cell_V_L.

[0046] Therefore, step 12 can be as follows: when the current discharge current is less than the reference discharge current (current SOP), the current minimum single cell voltage is less than the reference minimum single cell voltage Cell_V_L, and the current single cell voltage difference is less than the reference single cell voltage difference Cell_V_delta, according to the SOC-temperature-SOP table, the current SOC value is corrected to the next level of SOC value at the same temperature, and the first SOP value is corrected to the SOP value corresponding to the next level of SOC value at the same temperature as the second SOP value.

[0047] Specifically, it determines whether the current actual discharge current is less than or equal to the current SOP value, and whether the current minimum cell voltage MinV is less than the Cell_V_L corresponding to the current SOP, and whether the voltage difference between the maximum and minimum cell voltages is less than Cell_V_Delta. If so, the current SOP is inappropriate, triggering SOC correction: look up the SOC value corresponding to SOP1 at the current temperature condition, which is one step lower than SOP2 (SOP2 < SOP1), and directly correct the actual SOC to that value. The displayed SOC follows through smoothing, and the corresponding original SOP1 value will be reduced to SOP2.

[0048] As shown in the table below, if the current temperature is 50 degrees and the current SOC is 90%, then when revising the SOP, the SOC will be revised to the next level of 85%, and the SOP will be revised to the next level of 85% and the corresponding SOP2 for 50 degrees.

[0049] SOC\Temperature 57 55 50 45 25 10 0 -10 -15 -20 -25 95％ 90％ SOP1 85％ SOP2 …… 15％ 10％ 5％

[0050] The SOP correction method provided in the above embodiments includes: obtaining a current first SOP value; wherein the SOP value represents the battery power state; when the current discharge current is less than the reference discharge current, and the current minimum single-cell voltage is less than the reference minimum single-cell voltage, and the current single-cell voltage difference is less than the reference single-cell voltage difference, the first SOP value is corrected to a set second SOP value, wherein the second SOP value is less than the first SOP value; wherein the current single-cell voltage difference is the difference between the current maximum single-cell voltage and the current minimum single-cell voltage, the reference single-cell voltage difference is the difference between the reference maximum single-cell voltage and the reference minimum single-cell voltage, and the reference discharge current, the reference maximum single-cell voltage, and the reference minimum single-cell voltage are determined by the first SOP value. In this way, when the actual SOH and SOC of an electric vehicle battery system differ from the SOH and SOC calibration parameters obtained from the original test data due to the actual usage environment and operating conditions, the original calibration parameters can no longer accurately support the calibration of the actual battery system's SOH and SOC. At this time, the voltage characteristics generated by the use of the current SOP calibration parameters can reflect whether there is a large error in SOC and SOH, thereby achieving adaptive calibration of SOC, and then adaptive calibration of SOP, so that the battery system can work on a suitable voltage platform.

[0051] See Figure 3 , Figure 3 This is a flowchart illustrating a second embodiment of the SOP modification method provided in this application. The method includes:

[0052] Step 31: Obtain the current first SOP value.

[0053] The SOP value indicates the battery's state of power.

[0054] Step 32: When the current discharge current is less than the reference discharge current, the current minimum single cell voltage is less than the reference minimum single cell voltage, and the current single cell voltage difference is less than the reference single cell voltage difference, the first SOP value is corrected to the set second SOP value, where the second SOP value is less than the first SOP value.

[0055] Among them, the current single cell voltage difference is the difference between the current single cell voltage maximum value and the current single cell voltage minimum value, the reference single cell voltage difference is the difference between the reference single cell voltage maximum value and the reference single cell voltage minimum value, and the reference discharge current, the reference single cell voltage maximum value, and the reference single cell voltage minimum value are determined by the first SOP value.

[0056] Understandably, steps 21 and 22 described above are similar to steps 11 and 12 of the first embodiment described above, and will not be repeated here.

[0057] Step 33: Count the number of times the SOP value was corrected.

[0058] Optionally, the SOP value correction count only occurs when the previous charge reaches full charge voltage and charging is completed. When such SOC correction is triggered, the SOC correction count is incremented by 1, and only 1 count is accumulated during a single discharge process. Specifically, during the discharge process after the battery is fully charged, if SOP value correction is triggered, the SOP value correction count is incremented by 1, and the SOP value correction count is accumulated at most once during a single discharge process.

[0059] Step 34: When the number of SOP value corrections exceeds the set threshold, correct the current SOH value.

[0060] Among them, the SOH value indicates the battery's health status.

[0061] Optionally, such as Figure 4 As shown, Figure 4 yes Figure 3 A flowchart of an embodiment of step 34 is shown. Step 34 may specifically include:

[0062] Step 341: Obtain the SOC correction value when the battery meets the static correction conditions.

[0063] The static correction conditions are as follows: the battery system is left to stand for more than 1 hour, the lowest single cell voltage and the average voltage meet the static OCV voltage correction conditions, and the SOC corresponding to the voltage value is below 25% when looking up the table.

[0064] Step 342: Determine the actual battery capacity based on the SOC correction value.

[0065] Alternatively, the actual battery capacity can be calculated using the following formula:

[0066]

[0067] Step 343: Determine the SOH correction value based on the actual battery capacity, and use it as the current SOH value.

[0068] Alternatively, the SOH correction value can be calculated using the following formula:

[0069]

[0070] Understandably, this embodiment further corrects the SOH based on the correction of SOP and SOC in the first embodiment above, thereby achieving adaptive calibration of the actual SOH and SOC, and then achieving adaptive calibration of SOP, so that the battery system can work on a suitable voltage platform.

[0071] See Figure 5 , Figure 5This is a schematic diagram of an embodiment of the battery management system 500 provided in this application. The battery management system 500 includes a processor 51 and a memory 52. ​​The memory 52 is used to store program data, and the processor 51 is used to execute the program data to implement the following method:

[0072] Obtain the current first SOP value; where the SOP value represents the battery power state; when the current discharge current is less than the reference discharge current, and the current minimum single cell voltage is less than the reference minimum single cell voltage, and the current single cell voltage difference is less than the reference single cell voltage difference, the first SOP value is corrected to a set second SOP value, where the second SOP value is less than the first SOP value; where the current single cell voltage difference is the difference between the current maximum and minimum single cell voltage, the reference single cell voltage difference is the difference between the reference maximum and minimum single cell voltage, and the reference discharge current, the reference maximum single cell voltage, and the reference minimum single cell voltage are determined by the first SOP value.

[0073] Understandably, in one embodiment, the battery management system 500 may further include a BMS main board, a BMS slave board, etc. The BMS main board and the BMS slave board are connected by a bus. Generally, the BMS main board is located in the high-voltage box, and the BMS slave board is located in the battery box. The BMS slave board is connected to the battery through an adapter board.

[0074] See Figure 6 , Figure 6 This is a schematic diagram of an embodiment of the computer-readable storage medium 600 provided in this application. The computer-readable storage medium 600 stores program data 61, which, when executed by a processor, is used to execute the program data to implement the following method:

[0075] Obtain the current first SOP value; where the SOP value represents the battery power state; when the current discharge current is less than the reference discharge current, and the current minimum single cell voltage is less than the reference minimum single cell voltage, and the current single cell voltage difference is less than the reference single cell voltage difference, the first SOP value is corrected to a set second SOP value, where the second SOP value is less than the first SOP value; where the current single cell voltage difference is the difference between the current maximum and minimum single cell voltage, the reference single cell voltage difference is the difference between the reference maximum and minimum single cell voltage, and the reference discharge current, the reference maximum single cell voltage, and the reference minimum single cell voltage are determined by the first SOP value.

[0076] The display screen provided in the embodiments of this application has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for SOP correction, applied to a battery management system, characterized in that, The SOP represents the battery power state, and the SOP correction method includes: Obtain the current first SOP value; wherein, when the current discharge current is less than the reference discharge current, and the current minimum voltage of a single cell is less than the minimum voltage of a reference single cell, and the current voltage difference of a single cell is less than the voltage difference of a reference single cell, the first SOP value is corrected to a set second SOP value, wherein the second SOP value is less than the first SOP value; Wherein, the current single cell voltage difference is the difference between the current single cell voltage maximum value and the current single cell voltage minimum value, the reference single cell voltage difference is the difference between the reference single cell voltage maximum value and the reference single cell voltage minimum value, and the reference discharge current, the reference single cell voltage maximum value, and the reference single cell voltage minimum value are determined by the first SOP value; The method further includes: counting the number of SOP value corrections, and when the number of SOP value corrections exceeds a set threshold, correcting the current SOH value; wherein, the SOH value represents the battery health status.

2. The SOP correction method according to claim 1, characterized by, The step of obtaining the current first SOP value includes: Obtain the current SOC value and current temperature value; where the SOC value represents the battery's state of charge. Based on the pre-established SOC-Temperature-SOP table, the current SOC value and the corresponding SOP lookup value are obtained by looking up the table. The current first SOP value is determined by looking up the SOP table value.

3. The SOP correction method according to claim 2, characterized by, The step of determining the current first SOP value based on the SOP lookup table value includes: The current first SOP value is determined based on the SOP lookup table value and the current SOH value; wherein, the SOH value represents the battery health status.

4. The SOP correction method according to claim 2, characterized by, The step of correcting the first SOP value to a set second SOP value, wherein the second SOP value is less than the first SOP value, includes: According to the SOC-Temperature-SOP table, the current SOC value is corrected to the next level of SOC value at the same temperature, and the first SOP value is corrected to the SOP value corresponding to the next level of SOC value at the same temperature as the second SOP value.

5. The SOP correction method according to claim 1, characterized by, The method further includes: Based on the pre-established SOP-cell voltage range table, the maximum and minimum reference cell voltage values ​​corresponding to the first SOP value are obtained by looking up the table. The reference cell voltage difference is determined based on the difference between the maximum and minimum reference cell voltages.

6. The SOP correction method according to claim 1, wherein The number of times the statistical SOP value is corrected includes: During the discharge process after the battery is fully charged, if the SOP value correction is triggered, the SOP value correction count is incremented by 1, and the SOP value correction count is accumulated at most once during a single discharge process.

7. The SOP correction method according to claim 1, wherein The correction of the current SOH value includes: When the battery meets the static correction conditions, obtain the SOC correction value; The actual battery capacity is determined based on the SOC correction value. The SOH correction value is determined based on the actual capacity of the battery and used as the current SOH value.

8. A battery management system, characterized by, The battery management system includes a processor and a memory, the memory being used to store program data, and the processor being used to execute the program data to implement the SOP correction method as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program data, which, when executed by a processor, is used to implement the SOP correction method as described in any one of claims 1-7.

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