State of charge calibration method and apparatus, electronic device, and storage medium

Abstract

The application provides a state of charge calibration method and device, electronic equipment and storage medium, and belongs to the technical field of batteries, wherein the method comprises: obtaining a target voltage interval corresponding to a target battery at a current current during constant current charging and discharging of the target battery; determining the number of occurrences of at least one voltage of the target battery in the target voltage interval based on actual voltage data corresponding to the target battery in the target voltage interval; determining a target calibration voltage based on the number of occurrences of at least one voltage of the target battery in the target voltage interval; obtaining a target online state of charge corresponding to the target battery at the target calibration voltage, and calibrating the current state of charge of the target battery based on the target online state of charge. The application can calibrate the state of charge of the battery in real time, and the state of charge can still be effectively calibrated when the battery is in a voltage platform region, thereby improving the accuracy and reliability of the state of charge calibration.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and in particular to methods, apparatus, electronic devices, and storage media for calibrating the state of charge. Background Technology

[0002] State of Charge (SOC) is a core parameter that measures the ratio of a battery's remaining usable capacity to its fully charged capacity. To reduce errors caused by self-discharge, aging, and current integration during long-term battery use, and to ensure accurate and reliable power display, thereby preventing sudden power outages, extending battery life, and improving safety, SOC calibration is necessary.

[0003] In existing technologies, conventional calibration methods such as static calibration, full charge / discharge calibration, or low current calibration are commonly used for state of charge (SCC) calibration. Among these, static calibration and low current calibration require the battery voltage to be in a non-plateau region before SCC calibration can be performed; full charge / discharge calibration requires the battery to be charged to the cutoff voltage or discharged to the cutoff voltage before SCC calibration can be performed.

[0004] However, in off-grid conditions, the battery voltage cannot be in the non-plateau region, and the battery operating range is between 20% and 80%, failing to reach the cutoff voltage. This results in poor state-of-charge calibration accuracy using existing conventional calibration methods. Therefore, an effective solution is urgently needed to address these issues. Summary of the Invention

[0005] This invention provides a method, apparatus, electronic device, and storage medium for calibrating the state of charge (SCC) to solve the problem of poor SCC calibration accuracy in the off-grid state in the prior art.

[0006] In a first aspect, the present invention provides a method for calibrating the state of charge, comprising: During the constant current charge and discharge process of the target battery, the target voltage range corresponding to the target battery under the current current is obtained. The target voltage range is located in the voltage plateau region of the target battery, and the voltage fluctuation value of the target battery in the voltage plateau region is less than a preset threshold. Based on the actual voltage data of the target battery within the target voltage range, determine the number of times at least one voltage of the target battery occurs within the target voltage range; The target calibration voltage is determined based on the number of times at least one voltage of the target battery occurs within the target voltage range; Obtain the target online state of charge (SOC) of the target battery at the target calibration voltage, and calibrate the current SOC of the target battery based on the target online SOC.

[0007] In some embodiments, determining the target calibration voltage based on the number of occurrences of at least one voltage of the target battery within the target voltage range includes: A first voltage is determined based on the number of times at least one voltage of the target battery occurs within the target voltage range, wherein the first voltage is the voltage that occurs most frequently among the at least one voltage; If the first voltage meets a preset condition, the first voltage is determined to be the target calibration voltage. The preset condition includes that the number of times the first voltage occurs is greater than or equal to a first threshold.

[0008] In some embodiments, the preset condition further includes at least one of the following: The ratio of the number of occurrences of the first voltage to the total number of occurrences is greater than the second threshold, wherein the total number of occurrences is the sum of the number of occurrences of at least one voltage within the target voltage range; The at least one voltage includes at least one second voltage and at least one third voltage, wherein the second voltage is less than the first voltage, the third voltage is greater than the first voltage, and the number of occurrences of the second voltage and the number of occurrences of the third voltage are both greater than or equal to a third threshold.

[0009] In some embodiments, the third threshold is the product of the first threshold and the first preset ratio, or the third threshold is the product of the number of occurrences of the first voltage and the second preset ratio.

[0010] In some embodiments, obtaining the target voltage range corresponding to the target battery at the current current includes: From the multiple first reference voltage ranges corresponding to the target battery at different temperatures, multiple second reference voltage ranges corresponding to the target battery at the current temperature are determined, wherein the first reference voltage range is the voltage range corresponding to the target battery at zero current. Based on the current current, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges corresponding to the target battery under the current current. Based on the current voltage of the target battery, the target voltage range is selected from a plurality of the third reference voltage ranges.

[0011] In some embodiments, the step of converting multiple second reference voltage ranges based on the current current to obtain multiple third reference voltage ranges corresponding to the target battery under the current current includes: From a plurality of first internal resistance values ​​of the target battery at different temperatures and different states of charge, determine the second internal resistance value of the target battery at the current temperature and the current state of charge; Based on the current current and the second internal resistance value, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges.

[0012] In some of these embodiments, the second internal resistance value includes a first ohmic internal resistance value and a first electrochemical polarization internal resistance value; The process of converting multiple second reference voltage ranges based on the current current and the second internal resistance value to obtain multiple third reference voltage ranges includes: The fourth voltage is determined based on the sum of the first ohmic internal resistance and the first electrochemical polarization internal resistance, and the current current. Based on the fourth voltage, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges.

[0013] In some embodiments, the method further includes: For each of the different temperatures, perform the following steps: Based on the reference state of charge of the target battery in at least one reference voltage range at the temperature, a third internal resistance value corresponding to the at least one reference voltage range is selected from multiple first internal resistance values ​​of the target battery at the temperature and under different states of charge. The reference voltage range is determined in advance by constant current charge-discharge test of the target battery. Based on the reference current and the third internal resistance value corresponding to the at least one reference voltage range, the at least one reference voltage range is converted to obtain at least one first reference voltage range corresponding to the target battery at the temperature. The reference current is the current used to perform constant current charge and discharge test on the target battery.

[0014] In some of these embodiments, the third internal resistance value includes a second ohmic internal resistance value and a second electrochemical polarization internal resistance value. The step of converting the at least one reference voltage range based on the reference current and the third internal resistance value corresponding to the at least one reference voltage range to obtain at least one first reference voltage range corresponding to the target battery at the temperature includes: For each of the at least one reference voltage range, perform the following steps: The fifth voltage is determined based on the sum of the second ohmic internal resistance value and the second electrochemical polarization internal resistance value corresponding to the reference voltage range, and the reference current. Based on the fifth voltage, the reference voltage range is converted to obtain the first reference voltage range corresponding to the target battery at the specified temperature.

[0015] In some embodiments, the method further includes: Based on the hybrid pulse power characteristic HPPC test and the second-order RC equivalent battery model corresponding to the target battery, multiple first internal resistance values ​​of the target battery under different temperatures and different states of charge are determined.

[0016] In some embodiments, the method further includes: For each of the different temperatures, during the constant current charge-discharge test of the target battery at the temperature based on the reference current, at least one sixth voltage corresponding to the target battery at the reference current and the number of occurrences of the at least one sixth voltage are obtained; Based on the number of occurrences of the at least one sixth voltage, at least one reference voltage range corresponding to the target battery at the temperature and a reference state of charge for the at least one reference voltage range are determined.

[0017] In some embodiments, determining at least one reference voltage range corresponding to the target battery at the temperature based on the number of occurrences of the at least one sixth voltage includes: Arrange the occurrence counts of the at least one sixth voltage in ascending order of the at least one sixth voltage to obtain a list of occurrence counts; Based on the local maxima of the occurrence list, at least one quantity peak is determined; The voltage range in which the sixth voltage corresponding to the at least one number peak is located is determined as at least one reference voltage range corresponding to the target battery at the temperature.

[0018] In some embodiments, calibrating the current state of charge of the target battery based on the target online state of charge includes: Obtain the reference state of charge corresponding to the target voltage range; Based on the target online state of charge, the current state of charge, and the reference state of charge corresponding to the target voltage range, the calibration state of charge is determined; Based on the calibrated state of charge, the current state of charge is calibrated.

[0019] In some embodiments, determining the calibration state of charge based on the target online state of charge, the current state of charge, and the reference state of charge corresponding to the target voltage range includes: Determine the difference between the target online state of charge and the reference state of charge corresponding to the target voltage range; The calibrated state of charge is determined based on the difference between the current state of charge and the value. And / or, The calibration of the current state of charge based on the calibrated state of charge includes: Determine the deviation between the current state of charge and the calibrated state of charge; If the deviation exceeds the deviation threshold, the calibrated state of charge is determined as the current calibrated state of charge.

[0020] Secondly, the present invention also provides a state of charge calibration device, comprising: The acquisition module is configured to acquire the target voltage range of the target battery under the current current during the constant current charging and discharging process of the target battery. The target voltage range is located in the voltage plateau region of the target battery, and the voltage fluctuation value of the target battery in the voltage plateau region is less than a preset threshold. The first determining module is configured to determine the number of times at least one voltage of the target battery occurs in the target voltage range based on the actual voltage data of the target battery within the target voltage range. The second determining module is configured to determine a target calibration voltage based on the number of times the target battery exhibits at least one voltage within the target voltage range; The calibration module is configured to acquire the target online state of charge of the target battery at the target calibration voltage, and calibrate the current state of charge of the target battery based on the target online state of charge.

[0021] In some embodiments, the second determining module is specifically configured as follows: A first voltage is determined based on the number of times at least one voltage of the target battery occurs within the target voltage range, wherein the first voltage is the voltage that occurs most frequently among the at least one voltage; If the first voltage meets a preset condition, the first voltage is determined to be the target calibration voltage. The preset condition includes that the number of times the first voltage occurs is greater than or equal to a first threshold.

[0022] In some embodiments, the preset condition further includes at least one of the following: The ratio of the number of occurrences of the first voltage to the total number of occurrences is greater than the second threshold, wherein the total number of occurrences is the sum of the number of occurrences of at least one voltage within the target voltage range; The at least one voltage includes at least one second voltage and at least one third voltage, wherein the second voltage is less than the first voltage, the third voltage is greater than the first voltage, and the number of occurrences of the second voltage and the number of occurrences of the third voltage are both greater than or equal to a third threshold.

[0023] In some embodiments, the third threshold is the product of the first threshold and the first preset ratio, or the third threshold is the product of the number of occurrences of the first voltage and the second preset ratio.

[0024] In some embodiments, the acquisition module is specifically configured as follows: From the multiple first reference voltage ranges corresponding to the target battery at different temperatures, multiple second reference voltage ranges corresponding to the target battery at the current temperature are determined, wherein the first reference voltage range is the voltage range corresponding to the target battery at zero current. Based on the current current, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges corresponding to the target battery under the current current. Based on the current voltage of the target battery, the target voltage range is selected from a plurality of the third reference voltage ranges.

[0025] In some embodiments, the acquisition module is specifically configured as follows: From a plurality of first internal resistance values ​​of the target battery at different temperatures and different states of charge, determine the second internal resistance value of the target battery at the current temperature and the current state of charge; Based on the current current and the second internal resistance value, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges.

[0026] In some of these embodiments, the second internal resistance value includes a first ohmic internal resistance value and a first electrochemical polarization internal resistance value; The acquisition module is specifically configured as follows: The fourth voltage is determined based on the sum of the first ohmic internal resistance and the first electrochemical polarization internal resistance, and the current current. Based on the fourth voltage, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges.

[0027] In some embodiments, the apparatus further includes a conversion module configured to: For each of the different temperatures, perform the following steps: Based on the reference state of charge of the target battery in at least one reference voltage range at the temperature, a third internal resistance value corresponding to the at least one reference voltage range is selected from multiple first internal resistance values ​​of the target battery at the temperature and under different states of charge. The reference voltage range is determined in advance by constant current charge-discharge test of the target battery. Based on the reference current and the third internal resistance value corresponding to the at least one reference voltage range, the at least one reference voltage range is converted to obtain at least one first reference voltage range corresponding to the target battery at the temperature. The reference current is the current used to perform constant current charge and discharge test on the target battery.

[0028] In some of these embodiments, the third internal resistance value includes a second ohmic internal resistance value and a second electrochemical polarization internal resistance value. The conversion module is specifically configured as follows: For each of the at least one reference voltage range, perform the following steps: The fifth voltage is determined based on the sum of the second ohmic internal resistance value and the second electrochemical polarization internal resistance value corresponding to the reference voltage range, and the reference current. Based on the fifth voltage, the reference voltage range is converted to obtain the first reference voltage range corresponding to the target battery at the specified temperature.

[0029] In some embodiments, the apparatus further includes a third determining module configured to: Based on the hybrid pulse power characteristic HPPC test and the second-order RC equivalent battery model corresponding to the target battery, multiple first internal resistance values ​​of the target battery under different temperatures and different states of charge are determined.

[0030] In some embodiments, the apparatus further includes a test module configured to: During the constant current charge-discharge test of the target battery at the temperature based on the reference current, at least one sixth voltage corresponding to the target battery at the reference current and the number of occurrences of the at least one sixth voltage are obtained. Based on the number of occurrences of the at least one sixth voltage, at least one reference voltage range corresponding to the target battery at the temperature and a reference state of charge for the at least one reference voltage range are determined.

[0031] In some embodiments, the test module is specifically configured as follows: Arrange the occurrence counts of the at least one sixth voltage in ascending order to obtain a list of occurrence counts; Based on the local maxima of the occurrence list, at least one quantity peak is determined; The voltage range in which the sixth voltage corresponding to the at least one number peak is located is determined as at least one reference voltage range corresponding to the target battery at the temperature.

[0032] In some embodiments, the calibration module is specifically configured as follows: Obtain the reference state of charge corresponding to the target voltage range; Based on the target online state of charge, the current state of charge, and the reference state of charge corresponding to the target voltage range, the calibration state of charge is determined; Based on the calibrated state of charge, the current state of charge is calibrated.

[0033] In some embodiments, the calibration module is specifically configured as follows: Determine the difference between the target online state of charge and the reference state of charge corresponding to the target voltage range; The calibrated state of charge is determined based on the difference between the current state of charge and the value. And / or, The calibration module is specifically configured as follows: Determine the deviation between the target online state of charge and the calibrated state of charge; If the deviation exceeds the deviation threshold, the calibrated state of charge is determined as the current calibrated state of charge.

[0034] Thirdly, the present invention also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to implement the state of charge calibration method described in the first aspect above.

[0035] Fourthly, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the state of charge calibration method described in the first aspect above.

[0036] Fifthly, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the state of charge calibration method described in the first aspect above.

[0037] Compared with existing technologies, the state of charge (SOC) calibration method, apparatus, electronic device, and storage medium provided by this invention can determine the target voltage range of the target battery during constant current charge-discharge. Then, based on the frequency of different voltages occurring within the target voltage range, the target calibration voltage is determined. This allows for calibration of the current SOC by observing the target online SOC at the target calibration voltage. Thus, the target battery does not need to be static or shut down for SOC calibration; this invention allows calibration while the battery is online. Furthermore, the calibration process only requires ordinary constant current charge-discharge data, without the need for additional low-current or full charge-discharge operations, and can be performed in real-time during the battery's charge-discharge process. Additionally, the calibration method of this invention is unaffected by the inability to reach the cutoff voltage in non-plateau regions; the target battery can still be accurately calibrated even when it is in the voltage plateau region, improving the accuracy and reliability of SOC calibration.

[0038] Details of one or more embodiments of the present invention are set forth in the following drawings and description to make other features, objects and advantages of the invention more readily apparent. Attached Figure Description

[0039] The accompanying drawings, which are provided to further illustrate the invention, constitute a part of this invention. Those skilled in the art will recognize that other drawings can be derived from these drawings without any inventive effort. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation thereof.

[0040] Figure 1 This is a graph of the constant current charging data provided by the present invention.

[0041] Figure 2 This is one of the flowcharts of the state of charge calibration method provided by the present invention.

[0042] Figure 3 This is a curve of statistical voltage in the constant current charge-discharge test provided by the present invention.

[0043] Figure 4 This is a schematic diagram of the second-order RC equivalent battery model provided by the present invention.

[0044] Figure 5 This is the second schematic diagram of the state of charge calibration method provided by the present invention.

[0045] Figure 6 This is a schematic diagram of the data collection process in the offline stage provided by the present invention.

[0046] Figure 7 This is a schematic diagram of the state of charge calibration device provided by the present invention.

[0047] Figure 8 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0048] To more clearly understand the objectives, technical solutions, and advantages of this invention, the technical solutions of this invention will be clearly and completely described and explained below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0049] Unless otherwise defined, the technical or scientific terms used in this invention shall have the general meaning understood by one of ordinary skill in the art to which this invention pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these” used in this invention do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” and “coupled” used in this invention are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. “A plurality” used in this invention refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. Normally, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," "third," etc., used in this invention are merely for distinguishing similar objects and do not represent a specific ordering of the objects.

[0050] First, a brief description of the relevant content involved in this invention will be given.

[0051] The static calibration scheme in related technologies requires the battery to be left to stand in an open-circuit state for a relatively long time, typically ≥1 hour. Furthermore, Figure 1 This is a graph of the constant current charging data provided by the present invention, where the horizontal axis represents the state of charge and the vertical axis represents the voltage (in volts). Figure 1As shown, during constant current charging and discharging, a single voltage within the voltage plateau region (such as the range of 3.32V to 3.35V) may correspond to multiple different states of charge, making it impossible to determine the state of charge for each voltage. Therefore, the static calibration scheme also requires that the voltage not be in the voltage plateau region; otherwise, the open circuit voltage (OCV) cannot distinguish the state of charge.

[0052] The low-current calibration scheme in related technologies uses an extremely small current (such as 0.05 times the battery capacity, i.e., 0.05C) to charge and discharge the battery for a certain period of time. The charge and discharge time is usually ≥0.5 hours. It calibrates the state of charge in an approximate OCV manner, requiring the voltage to be in the non-voltage plateau region.

[0053] The full charge / discharge calibration schemes in related technologies calibrate the state of charge (SOC) by charging or discharging the battery to the cutoff voltage. However, in off-grid conditions, the battery voltage cannot be in the non-voltage plateau region, and the battery operating range cannot reach the cutoff voltage. This results in the inability of the static calibration scheme, the low-current calibration scheme, and the full charge / discharge calibration scheme to perform SOC calibration in off-grid conditions.

[0054] To address the aforementioned problems, this invention provides a method, apparatus, electronic device, and storage medium for calibrating the state of charge.

[0055] The following is combined Figures 2 to 7 The present invention describes a method, apparatus, electronic device, and storage medium for calibrating the state of charge.

[0056] Figure 2 This is one of the flowcharts illustrating the state of charge calibration method provided by the present invention, such as... Figure 2 As shown, the state of charge calibration method includes the following steps 201 to 204.

[0057] Step 201: During the constant current charge and discharge process of the target battery, obtain the target voltage range corresponding to the current current of the target battery.

[0058] The target voltage range is located within the voltage plateau region of the target battery. The voltage fluctuation of the target battery within the voltage plateau region is less than a preset threshold.

[0059] Specifically, the voltage plateau region refers to the area where the battery voltage changes very gradually or even almost constantly over a relatively wide range of capacity variations. The target voltage range can be the voltage range currently occupied by the target battery, determined considering the influence of rate capability.

[0060] In practical applications, during the online phase, the target battery can be charged and discharged at a constant current. Once the current is constant, the target voltage range corresponding to the target battery can be obtained based on the current.

[0061] Optionally, the method for obtaining the target voltage range corresponding to the target battery based on the current current can include any of the following: Method 1: Based on the current current, convert the voltage range corresponding to the target battery after reducing the influence of the rate, so as to obtain the target voltage range corresponding to the target battery under the current current.

[0062] Method 2: The target voltage range corresponding to the target battery under different currents is pre-stored. The current current is matched with each target voltage range to obtain the target voltage range corresponding to the target battery under the current current.

[0063] Step 202: Based on the actual voltage data of the target battery within the target voltage range, determine the number of times at least one voltage of the target battery occurs within the target voltage range.

[0064] Specifically, the actual voltage data includes the voltage (value) of the target battery at various times within a set time period. The set time period is the period from when the target battery voltage enters the target voltage range to when the target battery voltage exits the target voltage range.

[0065] For example, firstly, the actual voltage data generated by the target battery within the target voltage range is recorded; then, the occurrence count of each voltage (value) in the actual voltage data is counted, that is, the occurrence count of at least one voltage of the target battery within the target voltage range is obtained.

[0066] For example, if the target voltage range is [3V, 5V], and during constant current charging of the target battery, the target battery voltage is 4V when it enters the target voltage range, then the actual voltage data of the target battery within the [4V, 5V] range is obtained. If the voltage with the highest frequency corresponding to the target battery is within [4V, 5V], then a calibration point can be found from the actual voltage data, and the actual voltage data is valid. Subsequent calibration steps can be performed based on the actual voltage data. If the voltage with the highest frequency corresponding to the target battery is within [3V, 4V), then a calibration point cannot be found from the actual voltage data, and the actual voltage data is invalid. The actual voltage data can be re-obtained when the target battery voltage enters the target voltage range again, and the validity of the re-obtained actual voltage data can be verified according to the above steps.

[0067] Step 203: Determine the target calibration voltage based on the number of times the target battery exhibits at least one voltage within the target voltage range.

[0068] Specifically, the target calibration voltage can be the center voltage of the voltage plateau region. In actual determination, the frequency of occurrence of at least one voltage of the target battery within the target voltage range can be compared, and the voltage with the highest frequency of occurrence can be determined as the target calibration voltage.

[0069] For example, the highest and lowest occurrence counts can be determined based on the number of times different voltages of the target battery appear within the target voltage range. If the difference between the highest and lowest occurrence counts is greater than a preset number, the voltage corresponding to the highest occurrence count is determined as the target calibration voltage.

[0070] For example, a graph can be constructed based on the number of times different voltages of the target battery occur within the target voltage range, where the horizontal axis of the graph represents voltage and the vertical axis represents the number of times the voltage occurs. The voltage corresponding to the peak value in the graph can be used as the target calibration voltage.

[0071] Step 204: Obtain the target online state of charge of the target battery at the target calibration voltage, and calibrate the current state of charge of the target battery based on the target online state of charge.

[0072] For example, after determining the target calibration voltage, the online state of charge corresponding to the recorded target calibration voltage can be determined as the target online state of charge, and then the current state of charge can be calibrated based on the target online state of charge.

[0073] The state-of-charge (SOC) calibration method provided by this invention can determine the target voltage range of a target battery during constant current charge-discharge. Then, based on the frequency of different voltages occurring within the target voltage range, a target calibration voltage is determined. The current SOC is then calibrated using the target online SOC corresponding to the target calibration voltage. Thus, the target battery does not need to be static or shut down for SOC calibration; this invention allows calibration while the battery is online. The calibration process only requires ordinary constant current charge-discharge data, without the need for additional low-current or full-charge-discharge operations, and can be performed in real-time during the battery's charge-discharge process. Furthermore, the calibration method of this invention is not affected by the inability to reach the cutoff voltage in non-plateau regions; the target battery can still be accurately calibrated when it is in the voltage plateau region, improving the accuracy and reliability of SOC calibration.

[0074] In some embodiments, a specific implementation is provided for determining the target calibration voltage based on the number of times the target battery exhibits at least one voltage within a target voltage range. Specifically, step 203 above may include the following sub-steps: Step 203-1: Determine the first voltage based on the number of times the target battery has at least one voltage in the target voltage range. The first voltage is the voltage that has the highest number of occurrences among the at least one voltage. Step 203-2: If the first voltage meets the preset conditions, determine the first voltage as the target calibration voltage; wherein, the preset conditions include the first voltage occurring more than or equal to a first threshold.

[0075] Specifically, the first threshold can be set based on requirements, such as 100 or 500. In practical applications, the voltage that appears most frequently among different voltages can be determined first, and then it can be determined whether the first voltage meets the preset conditions.

[0076] If the first voltage does not meet the preset conditions, i.e., the number of times the first voltage occurs is less than the first threshold, it indicates that there may be a sudden change in current or an excessively rapid rise in battery temperature, causing the voltage to cross the range. Therefore, the first voltage is not the center voltage of the voltage plateau region and cannot be used as the target calibration voltage.

[0077] If the first voltage meets the preset condition, that is, the number of times the first voltage appears is greater than or equal to the first threshold, then the first voltage can be considered as the center voltage of the voltage plateau region. In this case, the first voltage can be used as the target calibration voltage.

[0078] In this embodiment of the invention, taking advantage of the characteristic that the voltage in the voltage plateau region is almost constant, the voltage at the center of the voltage plateau region usually appears the most frequently, the voltage that appears the most frequently and is greater than or equal to a first threshold is taken as the target calibration voltage, that is, the center voltage of the voltage plateau region. This improves the accuracy and reliability of determining the target calibration voltage, and thus the state of charge can be calibrated more accurately based on a more accurate target calibration voltage.

[0079] In some embodiments, the preset conditions further include at least one of the following: 1) The ratio of the number of occurrences of the first voltage to the total number of occurrences is greater than the second threshold. The total number of occurrences is the sum of the number of occurrences of at least one voltage within the target voltage range.

[0080] It should be noted that the total number of occurrences can also be understood as the total number of samples within the target voltage range. The ratio of the number of occurrences of the first voltage to the total number of occurrences can also be understood as the peak percentage of the target voltage range. The second threshold is greater than 0 and less than 1, and can be set according to requirements, for example, it can be set to 10%.

[0081] Specifically, the characteristic that a battery stays within a narrow voltage range for an extended period within a voltage plateau region can be utilized to further determine whether the aforementioned first voltage can be considered the center voltage of the voltage plateau region. For example, a "narrow voltage range" filtering condition can be set, where the ratio of the number of occurrences of the first voltage to the total number of occurrences is greater than a second threshold. If the first voltage meets this condition (i.e., the ratio is greater than the second threshold), it indicates that the longer the target battery stays near the first voltage, the more certain that the first voltage is the center voltage of the voltage plateau region, i.e., the target calibration voltage.

[0082] For example, a curve can be constructed based on the number of occurrences of at least one voltage within a target voltage range of the target battery, where the horizontal axis of the curve represents voltage and the vertical axis represents the number of occurrences. The voltage corresponding to the peak value in the curve is the first voltage. The larger the ratio of the number of occurrences of the first voltage to the total number of occurrences (the sum of the number of occurrences of multiple voltages), the narrower the peak corresponding to the first voltage, i.e., the narrower the voltage range. If the ratio is greater than a second threshold, it indicates that the width of the peak corresponding to the first voltage is less than the set width. In this case, the first voltage can be used as the target calibration voltage.

[0083] 2) At least one voltage includes at least one second voltage and at least one third voltage, the second voltage is less than the first voltage, the third voltage is greater than the first voltage, and the number of occurrences of the second voltage and the third voltage are both greater than or equal to the third threshold.

[0084] Specifically, a curve can be constructed based on the frequency of occurrence of at least one voltage within the target voltage range of the target battery. If the curve shows a single-sided peak, meaning the curve only rises or falls, it indicates that the first voltage is located at the edge of the target voltage range. In this case, the battery may exhibit significant polarization, high internal resistance, capacity decay, or abnormal testing conditions (such as low temperature or high current). If the first voltage is used as the target calibration voltage for state of charge calibration, the calibration error will be large. To address the above issues, this invention can set a "double-sided peak" screening condition, that is, determining that at least one voltage contains at least one second voltage and at least one third voltage. If the first voltage meets this condition (i.e., at least one voltage contains at least one second voltage and at least one third voltage), it indicates that at least one voltage within the target voltage range exhibits a "double-sided peak," and the first voltage within this range can be used as the center voltage of the voltage plateau region, i.e., the target calibration voltage.

[0085] For example, a curve (e.g., a histogram) can be constructed based on the number of occurrences of at least one voltage within a target voltage range for the target battery. The horizontal axis of the curve represents voltage, and the vertical axis represents the number of occurrences. The voltage corresponding to the peak value in the curve is the first voltage. If at least one second voltage and at least one third voltage exist, the peak value corresponding to the first voltage is a double-sided peak; if only at least one second voltage or at least one third voltage exists, the peak value corresponding to the first voltage is a single-sided peak. To avoid single-sided peaks, i.e., the curve within the target voltage range only shows an upward or downward trend, it is necessary to set a condition that at least one voltage includes at least one second voltage and at least one third voltage to ensure the reliability and accuracy of charge calibration.

[0086] Figure 3 This is a curve of statistical voltage in the constant current charge-discharge test provided by the present invention, to... Figure 3 For example, there are two peak waveforms within the voltage range [3.3, 3.4]. In any one of these peak waveforms, the highest point, i.e., the peak value, is the first voltage. The second voltage is located to the left of the first voltage, and the third voltage is located to the right of the first voltage. The number of occurrences of the second voltage and the third voltage is both greater than or equal to the third threshold, so that the second and third voltages are slightly lower than the first voltage. This peak waveform can be understood as the voltage value first rising from the second voltage on the left to the peak value (i.e., the first voltage), and then falling back from the peak value to the third voltage on the right. This peak waveform is a "double-sided peak," meaning it has both a rise and a fall.

[0087] Optionally, the third threshold is the product of the first threshold and the first preset ratio, or the third threshold is the product of the number of occurrences of the first voltage and the second preset ratio.

[0088] The first and second preset ratios can be set according to needs, such as the first preset ratio being 70% and the second preset ratio being 50%.

[0089] For example, the third threshold is the product of the first threshold and the first preset ratio. If the first preset ratio is 70%, then there are at least two points in the peak waveform whose peak height is greater than 70% of the first threshold, namely the points corresponding to the second voltage and the third voltage. Here, the peak height represents the value corresponding to each voltage point in the peak waveform.

[0090] For example, the first preset condition may include: the number of times the first voltage occurs is greater than a first threshold (e.g., 100); the ratio of the number of times the first voltage occurs to the total number of occurrences is greater than a second threshold (e.g., 10%); at least one voltage includes at least one second voltage and at least one third voltage, the second voltage is less than the first voltage, the third voltage is greater than the first voltage, and the number of times the second voltage occurs and the number of times the third voltage occurs are both greater than or equal to the product of the first threshold and the first preset ratio (e.g., 70%).

[0091] In this embodiment of the invention, a first threshold ensures that the number of occurrences of the finally determined target calibration voltage is sufficient, a second threshold ensures that the target voltage range in which the determined target calibration voltage is located meets the "narrow voltage range" requirement, and by setting a second voltage, a third voltage, and the corresponding third threshold, the target battery is ensured to be in a normal state within the target voltage range in which the determined target calibration voltage is located. Through the above-mentioned restrictions, the accuracy of the determined target calibration voltage is improved.

[0092] In some embodiments, the state of charge calibration method further includes: For each temperature, during the constant current charge-discharge test of the target battery at that temperature based on the reference current, at least one sixth voltage and the number of occurrences of the at least one sixth voltage corresponding to the target battery at the reference current are obtained; based on the number of occurrences of the at least one sixth voltage, at least one reference voltage range and the reference state of charge of the at least one reference voltage range corresponding to the target battery at that temperature are determined.

[0093] Specifically, the sixth voltage refers to the voltage corresponding to the target battery during the constant current charge-discharge test. The reference voltage range refers to the voltage range where the voltage fluctuation of the target battery is less than a preset threshold under a reference current. In practical applications, constant current charge-discharge tests can be performed on the target battery in an offline state at different temperatures: for any given temperature, a reference current can be used to perform a constant current charge-discharge test on the target battery, and the voltage (value) of the target battery at different times during the test is statistically analyzed. Based on the voltage (value) of the target battery at different times during the test, at least one sixth voltage corresponding to the target battery during the test and the number of occurrences of each sixth voltage are statistically analyzed. Based on the number of occurrences of all sixth voltages, at least one reference voltage range of the target battery at that temperature is determined, and then the reference state of charge for each reference voltage range is obtained.

[0094] For example, based on the number of occurrences of at least one sixth voltage, at least one reference voltage range corresponding to the target battery at this temperature can be determined. The implementation process can be as follows: a curve can be constructed based on the number of occurrences of at least one sixth voltage, where the horizontal axis of the curve is the sixth voltage and the vertical axis is the number of occurrences. At least one voltage in the above curve with a number of occurrences higher than the fourth threshold is taken as at least one seventh voltage.

[0095] For each seventh voltage, the voltage range corresponding to the peak of the seventh voltage in the curve is taken as the first reference voltage range. This process is repeated to obtain the first reference voltage ranges corresponding to all seventh voltages. After deduplication of the first reference voltage ranges corresponding to all seventh voltages, at least one first reference voltage range is obtained. Alternatively, the voltage range corresponding to each peak in the above curve can be taken as the first reference voltage range to obtain at least one first reference voltage range.

[0096] For example, see Figure 3 The graph takes the sixth voltage as an example. Its horizontal axis represents voltage (in volts), and its vertical axis represents the number of times the voltage appears. Figure 3 Three peaks appeared, each corresponding to a first reference voltage range. The first peak corresponds to a first reference voltage range of 3.22V to 3.26V, the second peak to 3.31V to 3.35V, and the third peak to 3.36V to 3.43V. The lines represent the signal, i.e., the number of occurrences of each sixth voltage; red circles represent peaks, black circles represent valleys, pink inverted triangles represent the starting point of a peak, and blue inverted triangles represent the ending point of a peak.

[0097] In this embodiment of the invention, taking advantage of the characteristic that the voltage of the target battery remains almost constant in the voltage plateau region and that the battery stays within a certain narrow voltage range for a long time, the first reference voltage range of the target battery and the first reference state of charge corresponding to each first reference voltage range at different temperatures are quickly and accurately obtained through offline identification. This provides parameter values ​​for subsequent online calibration of the state of charge, which is beneficial to improving the calibration rate and accuracy.

[0098] In some embodiments, based on the number of occurrences of at least one sixth voltage, at least one reference voltage range corresponding to the target battery at that temperature is determined. The implementation process can be as follows: the number of occurrences of at least one sixth voltage is arranged in ascending order of at least one sixth voltage to obtain a list of occurrences; based on the local maxima of the list of occurrences, at least one number peak is determined; the voltage ranges of the sixth voltages corresponding to the at least one number peak are determined as at least one reference voltage range corresponding to the target battery at that temperature.

[0099] In practical applications, the sixth voltages can be arranged in ascending order of voltage value to obtain an ordered list of voltage values ​​"v1, v2, ..., v". n "and the corresponding list of occurrences "c1, c2, ..., c n "Where, n is the number of types of the sixth voltage; v1 is the first sixth voltage in the voltage value list, c1 is the number of times v1 appears in the occurrence list; v2 is the second sixth voltage in the voltage value list, c2 is the number of times v2 appears in the occurrence list; v n For the nth sixth voltage in the voltage value list, c n v in the list of occurrences n The number of occurrences.

[0100] Furthermore, find all local maxima in the list of occurrences: for each occurrence in the list of occurrences except the first and last occurrences (c2 to c... n-1 If c i >c i−1 And c i >c i+1 Then mark c i Let c1 be a local maximum, where i is a positive integer and i∈[2,n−1]; for the first and last occurrences (boundary points) in the occurrence count list, if c1>c2, then c1 is a local maximum; if c n >c n-1 Then c n It is a local maximum.

[0101] It should be noted that if multiple consecutive occurrences of the same quantity appear in the quantity list, and each is the maximum value within its neighborhood (e.g., c), then... i−1 <c i =…=c i+k >c i+k+1 If k is less than or equal to n-1-i and greater than or equal to 3-i, then only one occurrence quantity can be taken as a local maximum. For example, the median occurrence quantity of the continuous segment can be selected as the local maximum.

[0102] Furthermore, each local maximum can be defined as at least one quantity peak. Alternatively, at least one quantity peak can be selected from each local maximum based on a preset peak threshold. For example, local maximums greater than the peak threshold can be used as quantity peaks. The peak threshold can be the product of the largest local maximum and a set percentage (e.g., 20%), thus eliminating smaller local maxima caused by noise.

[0103] Then, determine the reference voltage range for the sixth voltage corresponding to each quantity peak: find all local minima appearing in the quantity list; for any pair of adjacent quantity peaks in the quantity list, take the smallest local minima between these two quantity peaks as the quantity valley; using the sixth voltage corresponding to each quantity valley as the cutting point, divide the total voltage range [v1, v2, v3] into segments. n The voltage range is divided to obtain at least one reference voltage range.

[0104] The process of finding all the valley values ​​in the occurrence list can be as follows: For each occurrence in the occurrence list except for the first and last occurrences (c2 to c...), n-1 If c i <c i−1 And c i <c i+1 Then mark c i Let i be a local minimum, where i is a positive integer and i∈[2,n−1].

[0105] In this embodiment of the invention, by utilizing the characteristic that the voltage of the target battery remains almost constant in the voltage plateau region and that the battery stays within a narrow voltage range for a long time, the reference voltage range of the target battery at that temperature can be obtained quickly and accurately by using the number of peak values. This improves the accuracy of determining the reference voltage range and is beneficial to improving the speed and accuracy of subsequent calibration of the state of charge.

[0106] In some embodiments, the state of charge calibration method further includes: determining multiple first internal resistance values ​​of the target battery at different temperatures and under different states of charge based on the Hybrid Pulse Power Characterization (HPPC) test and the second-order RC (resistance-capacitance) equivalent battery model corresponding to the target battery.

[0107] Optionally, the first internal resistance value can be at least one corresponding actual value among ohmic internal resistance, electrochemical polarization internal resistance, and concentration polarization internal resistance.

[0108] In practical applications, since the first reference voltage range is the data of the target battery under the reference current, there is an influence of the current ratio. Therefore, it is necessary to reduce the influence of the current ratio on the state of charge calibration.

[0109] Specifically, a second-order RC equivalent battery model corresponding to the target battery can be set, such as... Figure 4 As shown, Figure 4 This is a schematic diagram of the second-order RC equivalent battery model provided by the present invention. Wherein, U ocAs an open-circuit voltage source, R0 is the ohmic internal resistance, R1 is the electrochemical polarization internal resistance, C1 is the electrochemical polarization capacitor, R2 is the concentration polarization internal resistance, C2 is the concentration polarization capacitor, and U... T The terminal voltage of the target battery is given. Furthermore, based on the second-order RC equivalent battery model corresponding to the target battery, HPPC testing is performed to obtain multiple first internal resistance values ​​of the target battery under different temperatures and different states of charge.

[0110] For each combination of temperature and state of charge (SOC), a standard current pulse is applied to the target battery (first discharging, then resting), and the terminal voltage response curve is recorded. The first internal resistance value for this combination can be determined based on different stages of the curve: Based on the principle that voltage jumps "step-like" during a sudden current change, the specific value of R0 is calculated based on the voltage jump value and the current value. The slowly changing voltage portion after the step (exponential curve) requires "curve fitting" using computer software to ensure the model output matches the measured curve, thereby solving for R1 and R2, etc.

[0111] In this embodiment of the invention, multiple first internal resistance values ​​of the target battery under different temperatures and different states of charge are determined by HPPC testing and a second-order RC equivalent battery model. This provides reliable data support for subsequent online state of charge calibration, which not only improves the accuracy of state of charge calibration but also avoids the need to measure the first internal resistance value in real time during the online stage, thereby improving the efficiency of state of charge calibration.

[0112] In some embodiments, the state of charge calibration method further includes: For each of the different temperatures, the following steps are performed: Based on the reference state of charge of the target battery in at least one reference voltage range at that temperature, a third internal resistance value corresponding to at least one reference voltage range is selected from multiple first internal resistance values ​​of the target battery at that temperature and under different states of charge. The reference voltage range is determined in advance by performing constant current charge-discharge tests on the target battery. Based on the reference current and the third internal resistance value corresponding to at least one reference voltage range, the at least one reference voltage range is converted to obtain at least one first reference voltage range corresponding to the target battery at that temperature. The reference current is the current used to perform constant current charge-discharge tests on the target battery.

[0113] It should be noted that since the reference voltage range is based on data from the target battery at a reference current, it is subject to the influence of the reference current. Therefore, to reduce the impact of the reference current on the voltage range, the reference voltage range can be converted based on the reference current.

[0114] Specifically, for each temperature and for each reference voltage range corresponding to the target battery at that temperature: based on the reference state of charge of that reference voltage range, a third internal resistance value corresponding to that reference voltage range can be selected from multiple first internal resistance values ​​of the target battery at that temperature and under different states of charge; then, according to Kirchhoff's voltage law, at least one reference voltage range is converted based on the reference current and the third internal resistance value, reducing the influence of the current in that reference voltage range at that temperature, thereby obtaining the first reference voltage range corresponding to that reference voltage range at that temperature.

[0115] It should be noted that, due to the relatively slow response time of the concentration polarization resistance, the current influence caused by the concentration polarization resistance in the first reference voltage range is relatively small. To reduce data processing while maintaining accuracy, at least one reference voltage range can be converted using only the ohmic resistance and electrochemical polarization resistance values ​​to minimize the current influence in that reference voltage range at that temperature.

[0116] In some embodiments, the third internal resistance value may include a second ohmic internal resistance value and a second electrochemical polarization internal resistance value; correspondingly, based on the reference current and the third internal resistance value corresponding to at least one reference voltage range, at least one reference voltage range is converted to obtain at least one first reference voltage range corresponding to the target battery at that temperature, and the implementation process can be as follows: For each of the at least one reference voltage range, the following steps are performed: a fifth voltage is determined based on the sum of the second ohmic internal resistance and the second electrochemical polarization internal resistance corresponding to the reference voltage range, and the reference current; based on the fifth voltage, the reference voltage range is converted to obtain the first reference voltage range corresponding to the target battery at that temperature.

[0117] For each reference voltage range, the reference voltage range can be converted according to the following formula to obtain the first reference voltage range corresponding to the target battery at that temperature.

[0118] ; Where R0 is the second ohmic internal resistance value in the third internal resistance value, R1 is the second electrochemical polarization internal resistance value in the current third internal resistance value, and V low V is the lower limit of the first reference voltage range. high V is the upper limit of the first reference voltage range. low_ref V is the lower limit of the reference voltage range. high_ref This is the upper limit of the voltage in this reference voltage range.

[0119] In this embodiment of the invention, by using the reference current and the third internal resistance value to convert the reference voltage range, the influence of the current in the reference voltage range at that temperature is reduced, and the voltage range reference value (i.e., the first reference voltage range) is obtained in an offline identification manner, which is beneficial to improving the calibration accuracy of the state of charge.

[0120] In some embodiments, a specific implementation method is provided for obtaining the target voltage range of the target battery at the current current. Specifically, step 201 above includes the following sub-steps: Step 201-1: Determine multiple second reference voltage ranges corresponding to the target battery at the current temperature from multiple first reference voltage ranges corresponding to the target battery at different temperatures; wherein, the first reference voltage range is the voltage range corresponding to the target battery at zero current. Step 201-2: Based on the current current, convert multiple second reference voltage ranges to obtain multiple third reference voltage ranges corresponding to the target battery under the current current. Step 201-3: Based on the current voltage of the target battery, select the target voltage range from multiple third reference voltage ranges.

[0121] Specifically, since each reference voltage range corresponds to a first reference voltage range at different temperatures, multiple first reference voltage ranges corresponding to the current temperature can be selected from the multiple first reference voltage ranges corresponding to all reference voltage ranges at different temperatures based on the current temperature of the target battery, and used as multiple second reference voltage ranges.

[0122] Since the second reference voltage range is based on data at zero current, it is unaffected by current. However, the target battery is currently charging and discharging based on the current current, so the influence of current needs to be considered. Therefore, this invention adds the influence of the current current on the voltage range to the second reference voltage range. That is, each second reference voltage range can be converted based on the current current to obtain multiple third reference voltage ranges for the target battery under the current current. Then, the current voltage of the target battery is matched with the multiple third reference voltage ranges, and the third reference voltage range containing the current voltage is taken as the target voltage range.

[0123] In this embodiment of the invention, a second reference voltage range corresponding to the current temperature is selected from a first reference voltage range at different temperatures. This not only narrows down the range of the target voltage range and improves the efficiency of obtaining the target voltage range, but also enhances the accuracy and reliability of the second reference voltage range. By converting the second reference voltage range using the current current, a third reference voltage range corresponding to the target battery at the current current is obtained. This makes the third reference voltage range more consistent with the current operating conditions of the target battery, thereby improving its accuracy and reliability. Matching the current voltage of the target battery with the third reference voltage range to determine the target voltage range improves the accuracy of determining the target voltage range to a certain extent, thus improving calibration accuracy.

[0124] In some embodiments, a specific implementation is provided that, based on the current current, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges corresponding to the target battery under the current current. Specifically, step 201-3 above includes the following sub-steps: Step 201-3-1: Determine the second internal resistance value of the target battery at the current temperature and current state of charge from multiple first internal resistance values ​​of the target battery at different temperatures and different states of charge. Step 201-3-2: Based on the current current and the second internal resistance value, convert multiple second reference voltage ranges to obtain multiple third reference voltage ranges.

[0125] It should be noted that the internal resistance of a battery typically varies with different temperatures and states of charge, which can easily lead to varying degrees of influence of the current on the voltage range. Therefore, this invention also considers the current temperature and current state of charge when performing voltage range conversion, thereby improving the accuracy of the converted voltage range.

[0126] Specifically, the current temperature and current state of charge (SOC) can be matched with multiple first internal resistance values ​​of the target battery at different temperatures and SOCs, and the first internal resistance value corresponding to the current temperature and current SOC is used as the second internal resistance value. For each second reference voltage range, multiple second reference voltage ranges can be converted based on the current current and the second internal resistance value according to Kirchhoff's voltage law. Since the influence of the current temperature and current SOC is taken into account, a third reference voltage range that is more consistent with the battery's operating conditions can be obtained.

[0127] It should be noted that because the response time of concentration polarization resistance is relatively slow, the current influence caused by concentration polarization resistance in the voltage range is relatively small. To reduce data processing while maintaining accuracy, at least one second reference voltage range can be converted using only the ohmic resistance and electrochemical polarization resistance values ​​to minimize the current influence in that second reference voltage range.

[0128] In some embodiments, the second internal resistance value includes a first ohmic internal resistance value and a first electrochemical polarization internal resistance value; correspondingly, based on the current current and the second internal resistance value, a plurality of second reference voltage ranges are converted to obtain a plurality of third reference voltage ranges, including: Based on the sum of the first ohmic internal resistance and the first electrochemical polarization internal resistance, and the current, a fourth voltage is determined; based on the fourth voltage, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges.

[0129] Specifically, for each second reference voltage range, the second reference voltage range can be converted according to the following formula to obtain the target voltage range.

[0130] ; in, This is the first ohmic internal resistance value in the second internal resistance value. V is the first electrochemical polarization internal resistance value in the second internal resistance value. low V is the lower limit of the second reference voltage range. high V is the upper limit of the second reference voltage range. low_cur V is the lower limit of the third reference voltage range. high_cur This is the upper limit of the voltage in the third reference voltage range.

[0131] In this embodiment of the invention, when performing the conversion of the second reference voltage range, the current temperature and the current state of charge are taken into account, which improves the accuracy of the converted voltage range and improves the matching degree between the third reference voltage range and the current operating condition of the target battery. Therefore, when determining the target voltage range from the third reference voltage range, the accuracy of the target voltage range can be improved, which is beneficial to improving the calibration accuracy of the state of charge.

[0132] In some embodiments, a specific implementation is provided for calibrating the current state of charge of a target battery based on the target online state of charge. Specifically, step 204 above includes the following sub-steps: Step 204-1: Obtain the reference state of charge corresponding to the target voltage range; Step 204-2: Determine the calibration state of charge based on the target online state of charge, the current state of charge, and the reference state of charge corresponding to the target voltage range; Step 204-3: Based on the calibration state of charge, calibrate the current state of charge.

[0133] Specifically, since the first reference voltage range is obtained by converting the reference voltage range, for each reference voltage range, the reference state of charge corresponding to the reference state of charge can be used as the reference state of charge corresponding to the first reference voltage range obtained after the conversion of the reference state of charge.

[0134] Since the target voltage range is obtained by converting the first reference voltage range, the reference state of charge corresponding to the first reference voltage range can be used as the reference state of charge for the target voltage range. Then, the deviation between the target online state of charge and the reference state of charge corresponding to the target voltage range is calculated, and combined with the current state of charge, a calibration state of charge is determined to calibrate the current state of charge.

[0135] In this embodiment of the invention, the reference state of charge used for calibration is determined by the target voltage range, making the reference state of charge more consistent with the current operating conditions and improving the accuracy and reliability of the reference state of charge. Furthermore, the calibration state of charge is determined by the target online state of charge, the current state of charge, and the reference state of charge corresponding to the target voltage range, thereby calibrating the current state of charge and improving the accuracy and precision of the calibration state of charge to a certain extent.

[0136] In some embodiments, a specific implementation is provided for determining the calibration state of charge based on the target online state of charge, the current state of charge, and the reference state of charge corresponding to the target voltage range. Specifically, step 204-3 above includes the following sub-steps: Step 204-3-1: Determine the difference between the target online state of charge and the reference state of charge corresponding to the target voltage range; Step 204-3-2: Determine the calibration state of charge based on the current state of charge and the difference.

[0137] Specifically, the calibration state of charge can be determined using the following formula: SOC new =SOC cur -(SOC online -SOC ref ); Among them, SOC new To calibrate the state of charge, SOC cur The current state of charge (SOC) online For the target online state of charge, SOC ref This is the reference state of charge corresponding to the target voltage range.

[0138] In this embodiment of the invention, the current state of charge is adjusted by the difference between the target online state of charge and the reference state of charge corresponding to the target voltage range to obtain a calibrated state of charge. This can achieve smooth and accurate correction of the current state of charge without relying on a single fixed calibration point, while avoiding abrupt changes and miscalibration.

[0139] In some embodiments, a specific implementation is provided for calibrating the current state of charge based on the calibration state of charge. Specifically, step 204-4 above includes the following sub-steps: Step 204-4-1: Determine the deviation between the current state of charge and the calibrated state of charge; Step 204-4-2: If the deviation exceeds the deviation threshold, the calibrated state of charge is determined as the current state of charge after calibration.

[0140] Specifically, after obtaining the calibrated state of charge, calibration can be performed directly based on the calibrated state of charge, that is, the calibrated state of charge is determined as the current state of charge after calibration.

[0141] In addition, to reduce the number of calibrations, it can be first determined whether the deviation between the current state of charge and the calibrated state of charge exceeds the deviation threshold: if so, the error of the current state of charge is considered to be large, and the current state of charge needs to be calibrated using the calibrated state of charge; if not, the error of the current state of charge is considered to be small, and within the allowable error range, there is no need to calibrate the current state of charge.

[0142] In this embodiment of the invention, by comparing the deviation between the current state of charge and the calibrated state of charge, it is determined whether the current state of charge needs to be calibrated. This can reduce the number of calibrations while ensuring that the error of the current state of charge is within the allowable range.

[0143] The following is combined Figure 5 The state of charge calibration method provided by the present invention will be further described.

[0144] Figure 5 This is the second schematic flowchart of the state of charge calibration method provided by this invention. Figure 5 As shown, this state of charge calibration method consists of two parts: an offline stage and an online stage. The offline phase includes the following steps: Step 501: Perform a constant current charge-discharge test on the target battery. Specifically, for each temperature, during the constant current charge-discharge test of the target battery at that temperature based on the reference current, obtain at least one sixth voltage and the number of occurrences of the at least one sixth voltage corresponding to the target battery at the reference current; and based on the number of occurrences of the at least one sixth voltage, determine at least one reference voltage range and the reference state of charge corresponding to the at least one reference voltage range of the target battery at that temperature.

[0145] Figure 6 This is a schematic diagram of the offline data acquisition process provided by the present invention. See [link / reference] Figure 6 The offline phase includes two parts: constant current charge-discharge testing and HPPC testing. In the constant current charge-discharge testing, different temperatures are set, including 10℃, 20℃, and 30℃. Further, a reference current is used to perform constant current charge-discharge tests on the target battery at temperatures of 10℃, 20℃, and 30℃, obtaining the following reference voltage ranges for the target battery at 10℃: reference voltage range 1 and its corresponding reference state of charge 1, reference voltage range 2 and its corresponding reference state of charge 2, reference voltage range 3 and its corresponding reference state of charge 3, etc.; reference voltage range 4 and its corresponding reference state of charge 4, reference voltage range 5 and its corresponding reference state of charge 5, reference voltage range 6 and its corresponding reference state of charge 6, etc.; and reference voltage range 7 and its corresponding reference state of charge 7, reference voltage range 8 and its corresponding reference state of charge 8, reference voltage range 9 and its corresponding reference state of charge 9, etc.

[0146] Step 502: Perform HPPC testing based on the second-order RC equivalent cell model of the target battery. Specifically, based on the HPPC test and the second-order RC equivalent cell model corresponding to the target battery, determine multiple first internal resistance values ​​of the target battery at different temperatures and under different states of charge.

[0147] For example, see Figure 6 HPPC testing was conducted, setting different states of charge (SOCs), including SOC 1, SOC 2, and SOC 3. Further, HPPC tests were performed on the second-order RC equivalent battery model of the target battery at temperatures of 10°C, 20°C, and 30°C, yielding the following internal resistance values: at 10°C, the first internal resistance value 1 under SOC 1, the first internal resistance value 2 under SOC 2, and the first internal resistance value 3 under SOC 3; at 20°C, the first internal resistance value 4 under SOC 1, the first internal resistance value 5 under SOC 2, and the first internal resistance value 6 under SOC 3; and at 30°C, the first internal resistance value 7 under SOC 1, the first internal resistance value 8 under SOC 2, and the first internal resistance value 9 under SOC 3.

[0148] Step 503: Reduce the influence of current in the reference voltage range. Specifically, for each temperature under different conditions, based on the reference state of charge of the target battery in at least one reference voltage range corresponding to that temperature, select a third internal resistance value corresponding to at least one reference voltage range from multiple first internal resistance values ​​of the target battery at that temperature and under different states of charge. The reference voltage range is determined in advance by performing constant current charge-discharge tests on the target battery. Based on the reference current and the third internal resistance value corresponding to at least one reference voltage range, convert at least one reference voltage range to obtain at least one first reference voltage range corresponding to the target battery at that temperature.

[0149] The online phase includes the following steps: Step 504: Filter the reference voltage range. Specifically, from the multiple first reference voltage ranges corresponding to the target battery at different temperatures, determine the multiple second reference voltage ranges corresponding to the target battery at the current temperature.

[0150] Step 505: Convert the reference voltage range. Specifically, based on the current current, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges corresponding to the target battery under the current current.

[0151] Step 506: Determine the target voltage range. Specifically, based on the current voltage of the target battery, the target voltage range is selected from multiple third reference voltage ranges.

[0152] Step 507: Determine the first voltage. Specifically, based on the actual voltage data of the target battery within the target voltage range, determine the frequency of occurrence of at least one voltage of the target battery within the target voltage range; and determine the voltage with the highest frequency among the at least one voltages as the first voltage.

[0153] Step 508: Determine whether the first voltage meets the preset conditions. If yes, proceed to step 509; otherwise, return to step 504 to continue execution.

[0154] Specifically, the preset conditions include: the number of occurrences of the first voltage is greater than or equal to the first threshold; the ratio of the number of occurrences of the first voltage to the total number of occurrences is greater than the second threshold, and the total number of occurrences is the sum of the number of occurrences of at least one voltage within the target voltage range; at least one voltage includes at least one second voltage and at least one third voltage, the second voltage is less than the first voltage, the third voltage is greater than the first voltage, and the number of occurrences of the second voltage and the third voltage are both greater than or equal to the third threshold, wherein the third threshold is the product of the first threshold and the first preset ratio, or the third threshold is the product of the number of occurrences of the first voltage and the second preset ratio.

[0155] Step 509: Use the first voltage as the target calibration voltage.

[0156] Step 510: Obtain the reference state of charge corresponding to the target voltage range.

[0157] Step 511: Determine the calibration state of charge. Specifically, determine the difference between the target online state of charge corresponding to the target calibration voltage and the reference state of charge corresponding to the target voltage range; based on the current state of charge and the difference, determine the calibration state of charge.

[0158] Step 512: Determine the deviation between the current state of charge and the calibrated state of charge.

[0159] Step 513: Determine whether the deviation exceeds the deviation threshold; if yes, proceed to step 514; otherwise, return to step 504 to continue execution.

[0160] Step 514: Determine the calibrated state of charge as the current calibrated state of charge.

[0161] The state-of-charge (SOC) calibration method provided by this invention can determine the target voltage range of a target battery during constant current charge-discharge. Then, based on the frequency of different voltages occurring within the target voltage range, a target calibration voltage is determined. The current SOC is then calibrated using the target online SOC corresponding to the target calibration voltage. Thus, the target battery does not need to be static or shut down for SOC calibration; this invention allows calibration while the battery is online. The calibration process only requires ordinary constant current charge-discharge data, without the need for additional low-current or full-charge-discharge operations, and can be performed in real-time during the battery's charge-discharge process. Furthermore, the calibration method of this invention is not affected by the inability to reach the cutoff voltage in non-plateau regions; the target battery can still be accurately calibrated when it is in the voltage plateau region, improving the accuracy and reliability of SOC calibration.

[0162] Furthermore, the state of charge calibration method provided by this invention requires only a small amount of offline calibration data, is compatible with different charge / discharge rates and temperatures, consumes little computational resources, and can achieve online calibration of the state of charge without floating-point differentiation, complex filtering, or iterative processes, thereby reducing the cost of state of charge calibration and improving its robustness and ease of implementation.

[0163] It should be noted that the steps shown in the above flowchart or the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here. For example, steps 501 and 502 may be performed simultaneously, or step 501 may be executed first, followed by step 502, or step 502 may be executed first, followed by step 501.

[0164] The present invention also provides a state of charge calibration device for implementing the above embodiments and preferred embodiments, the details of which will not be repeated. The terms "module," "unit," "subunit," etc., used below refer to combinations of software and / or hardware that implement a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0165] The state of charge calibration device provided by the present invention is described below. The state of charge calibration device described below can be referred to in correspondence with the state of charge calibration method described above.

[0166] Figure 7 This is a schematic diagram of the structure of the state of charge calibration device provided by the present invention, as shown below. Figure 7 As shown, the state of charge calibration device includes: The acquisition module 701 is configured to acquire the target voltage range of the target battery under the current current during the constant current charging and discharging process of the target battery. The target voltage range is located in the voltage plateau region of the target battery, and the voltage fluctuation value of the target battery in the voltage plateau region is less than a preset threshold. The first determining module 702 is configured to determine the number of times at least one voltage of the target battery occurs within the target voltage range based on the actual voltage data of the target battery within the target voltage range. The second determining module 703 is configured to determine the target calibration voltage based on the number of times the target battery exhibits at least one voltage within the target voltage range; The calibration module 704 is configured to acquire the target online state of charge of the target battery at the target calibration voltage, and calibrate the current state of charge of the target battery based on the target online state of charge.

[0167] The state of charge (SOC) calibration device provided by this invention can determine the target voltage range of a target battery during constant current charge-discharge. Then, based on the frequency of different voltages occurring within the target voltage range, a target calibration voltage is determined. This allows for calibration of the current SOC by analyzing the target online SOC corresponding to the target calibration voltage. Thus, the target battery does not need to be static or shut down for SOC calibration; this invention allows calibration while the battery is online. Furthermore, the calibration process only requires ordinary constant current charge-discharge data, eliminating the need for additional low-current or full-charge-discharge operations. Real-time calibration can be performed during the battery's charge-discharge process. Additionally, the calibration method of this invention is unaffected by the inability to reach the cutoff voltage in non-plateau regions. Even when the target battery is in the voltage plateau region, accurate SOC calibration can still be performed, improving the accuracy and reliability of SOC calibration.

[0168] It should be noted that the above modules can be functional modules or program modules, and can be implemented through software or hardware. For modules implemented through hardware, the above modules can reside in the same processor; or the above modules can be located in different processors in any combination.

[0169] Figure 8 This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 8 As shown, the electronic device may include a processor 810, a communications interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communications interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call logical instructions in the memory 830 to execute a state of charge calibration method, which includes: during constant current charging and discharging of the target battery, obtaining a target voltage range corresponding to the target battery at the current current, wherein the target voltage range is located in the voltage plateau region of the target battery, and the voltage fluctuation value of the target battery in the voltage plateau region is less than a preset threshold; determining the number of times at least one voltage of the target battery occurs in the target voltage range based on the actual voltage data corresponding to the target battery in the target voltage range; determining a target calibration voltage based on the number of times at least one voltage of the target battery occurs in the target voltage range; obtaining the target online state of charge of the target battery at the target calibration voltage, and calibrating the current state of charge of the target battery based on the target online state of charge.

[0170] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0171] The present invention also provides an electronic device including a memory and a processor, the memory storing a computer program and the processor being configured to run the computer program to perform the steps in any of the above method embodiments.

[0172] Optionally, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor and the input / output device is connected to the processor.

[0173] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated in this embodiment.

[0174] On the other hand, in conjunction with the state of charge calibration method provided in the above embodiments, the present invention also provides a non-transitory computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps in any of the above embodiments of the state of charge calibration method.

[0175] In another aspect, in conjunction with the state of charge calibration method provided in the above embodiments, the present invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the steps in any of the above method embodiments.

[0176] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0177] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0178] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for calibrating the state of charge, characterized in that, include: During the constant current charge and discharge process of the target battery, the target voltage range corresponding to the target battery under the current current is obtained. The target voltage range is located in the voltage plateau region of the target battery, and the voltage fluctuation value of the target battery in the voltage plateau region is less than a preset threshold. Based on the actual voltage data of the target battery within the target voltage range, determine the number of times at least one voltage of the target battery occurs within the target voltage range; The target calibration voltage is determined based on the number of times at least one voltage of the target battery occurs within the target voltage range; Obtain the target online state of charge of the target battery at the target calibration voltage, and calibrate the current state of charge of the target battery based on the target online state of charge; Determining the target calibration voltage based on the number of occurrences of at least one voltage of the target battery within the target voltage range includes: A first voltage is determined based on the number of times at least one voltage of the target battery occurs within the target voltage range, wherein the first voltage is the voltage that occurs most frequently among the at least one voltage; If the first voltage meets a preset condition, the first voltage is determined to be the target calibration voltage. The preset condition includes that the number of times the first voltage occurs is greater than or equal to a first threshold.

2. The state of charge calibration method according to claim 1, characterized in that, The preset conditions also include at least one of the following: The ratio of the number of occurrences of the first voltage to the total number of occurrences is greater than the second threshold, wherein the total number of occurrences is the sum of the number of occurrences of at least one voltage within the target voltage range; The at least one voltage includes at least one second voltage and at least one third voltage, wherein the second voltage is less than the first voltage, the third voltage is greater than the first voltage, and the number of occurrences of the second voltage and the number of occurrences of the third voltage are both greater than or equal to a third threshold.

3. The state of charge calibration method according to claim 2, characterized in that, The third threshold is the product of the first threshold and the first preset ratio, or the third threshold is the product of the number of occurrences of the first voltage and the second preset ratio.

4. The state of charge calibration method according to claim 1, characterized in that, The step of obtaining the target voltage range of the target battery under the current current includes: From the multiple first reference voltage ranges corresponding to the target battery at different temperatures, multiple second reference voltage ranges corresponding to the target battery at the current temperature are determined, wherein the first reference voltage range is the voltage range corresponding to the target battery at zero current. Based on the current current, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges corresponding to the target battery under the current current. Based on the current voltage of the target battery, the target voltage range is selected from a plurality of the third reference voltage ranges.

5. The state of charge calibration method according to claim 4, characterized in that, The step of converting multiple second reference voltage ranges based on the current current to obtain multiple third reference voltage ranges corresponding to the target battery under the current current includes: From a plurality of first internal resistance values ​​of the target battery at different temperatures and different states of charge, determine the second internal resistance value of the target battery at the current temperature and the current state of charge; Based on the current current and the second internal resistance value, multiple second reference voltage ranges are converted to obtain multiple third reference voltage ranges; And / or, the method further includes: For each of the different temperatures, perform the following steps: Based on the reference state of charge of the target battery in at least one reference voltage range at the temperature, a third internal resistance value corresponding to the at least one reference voltage range is selected from multiple first internal resistance values ​​of the target battery at the temperature and under different states of charge. The reference voltage range is determined in advance by constant current charge-discharge test of the target battery. Based on the reference current and the third internal resistance value corresponding to the at least one reference voltage range, the at least one reference voltage range is converted to obtain at least one first reference voltage range corresponding to the target battery at the temperature. The reference current is the current used to perform constant current charge and discharge test on the target battery.

6. The state of charge calibration method according to claim 5, characterized in that, The method further includes: For each of the different temperatures, during the constant current charge-discharge test of the target battery at the temperature based on the reference current, at least one sixth voltage corresponding to the target battery at the reference current and the number of occurrences of the at least one sixth voltage are obtained; Based on the number of occurrences of the at least one sixth voltage, at least one reference voltage range corresponding to the target battery at the temperature and a reference state of charge for the at least one reference voltage range are determined.

7. The state of charge calibration method according to claim 6, characterized in that, Determining at least one reference voltage range corresponding to the target battery at the temperature based on the number of occurrences of the at least one sixth voltage includes: Arrange the occurrence counts of the at least one sixth voltage in ascending order to obtain a list of occurrence counts; Based on the local maxima of the occurrence list, at least one quantity peak is determined; The voltage range in which the sixth voltage corresponding to the at least one number peak is located is determined as at least one reference voltage range corresponding to the target battery at the temperature.

8. The state of charge calibration method according to any one of claims 1-7, characterized in that, The calibration of the current state of charge of the target battery based on the target online state of charge includes: Obtain the reference state of charge corresponding to the target voltage range; Based on the target online state of charge, the current state of charge, and the reference state of charge corresponding to the target voltage range, the calibration state of charge is determined; Based on the calibrated state of charge, the current state of charge is calibrated.

9. The state of charge calibration method according to claim 8, characterized in that, The step of determining the calibration state of charge based on the target online state of charge, the current state of charge, and the reference state of charge corresponding to the target voltage range includes: Determine the difference between the target online state of charge and the reference state of charge corresponding to the target voltage range; The calibrated state of charge is determined based on the difference between the current state of charge and the value. And / or, The calibration of the current state of charge based on the calibrated state of charge includes: Determine the deviation between the current state of charge and the calibrated state of charge; If the deviation exceeds the deviation threshold, the calibrated state of charge is determined as the current calibrated state of charge.

10. A state of charge calibration device, characterized in that, include: The acquisition module is configured to acquire the target voltage range of the target battery under the current current during the constant current charging and discharging process of the target battery. The target voltage range is located in the voltage plateau region of the target battery, and the voltage fluctuation value of the target battery in the voltage plateau region is less than a preset threshold. The first determining module is configured to determine the number of times at least one voltage of the target battery occurs in the target voltage range based on the actual voltage data of the target battery within the target voltage range. The second determining module is configured to determine a target calibration voltage based on the number of times the target battery exhibits at least one voltage within the target voltage range; The calibration module is configured to acquire the target online state of charge of the target battery at the target calibration voltage, and calibrate the current state of charge of the target battery based on the target online state of charge. The second determining module is specifically configured to determine a first voltage based on the number of times at least one voltage of the target battery occurs within the target voltage range, wherein the first voltage is the voltage that occurs most frequently among the at least one voltage; and determine the first voltage as the target calibration voltage if the first voltage meets a preset condition, wherein the preset condition includes the number of times the first voltage occurs being greater than or equal to a first threshold.

11. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the state of charge calibration method according to any one of claims 1 to 9.

12. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the state of charge calibration method according to any one of claims 1 to 9.

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