Charge state calibration method, device, medium, product, system and equipment

Abstract

The embodiment of the invention provides a state of charge calibration method and device, a medium, a product, a system and equipment. The state of charge calibration method comprises the following steps: acquiring a first measurement terminal voltage of a battery and a first working condition index corresponding to the first measurement terminal voltage; based on the equivalent circuit model of the battery and the current charge state of the battery, determining a first model terminal voltage corresponding to the battery under the first working condition index; determining a first voltage error of the first model terminal voltage based on the first measurement terminal voltage; and under the condition that the first working condition index meets the target working condition and the first voltage error is not in a reference voltage error range corresponding to the target working condition, calibrating the current state of charge of the battery based on the first voltage error and the reference voltage error range. Therefore, whether the current state of charge of the battery needs to be calibrated or not can be identified more accurately, the accuracy of state of charge calibration is improved, and the problem of over-voltage or under-voltage of the battery caused by deviation of the state of charge is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to methods, devices, media, products, systems and equipment for calibrating the state of charge. Background Art

[0002] This section is intended to provide a background or context for the embodiments of the present application. No description herein is admitted to be prior art by virtue of its inclusion in this section.

[0003] In the related art, if the long-term accumulated state of charge (SOC) deviation during the use of the battery is not corrected, it will cause unexpected phenomena such as overvoltage or undervoltage of the battery, thereby affecting the performance of the electrical equipment supported by the battery.

[0004] Therefore, with the widespread application of batteries, how to correct the state of charge of the battery is a problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the embodiments of the present application hope to provide a state of charge calibration method, device, medium, product, system and equipment, which can correct the SOC deviation accumulated during the use of the battery, reduce problems such as battery overvoltage or battery undervoltage caused by SOC deviation, thereby improving the performance of battery products.

[0006] The present application provides a method for calibrating a state of charge, the method comprising: Acquire a first measurement terminal voltage of the battery and a first operating condition indicator corresponding to the first measurement terminal voltage; Determine a first model terminal voltage corresponding to the battery under a first operating condition indicator based on an equivalent circuit model of the battery and a current state of charge of the battery; Determining a first voltage error of a first model terminal voltage based on the first measurement terminal voltage; When the first operating condition indicator meets the target operating condition and the first voltage error is not within the reference voltage error range corresponding to the target operating condition, the current state of charge of the battery is calibrated based on the first voltage error and the reference voltage error range; the reference voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trustworthy condition.

[0007] In an embodiment of the present application, a first measurement terminal voltage of the battery and a corresponding first operating condition indicator are obtained; based on an equivalent circuit model of the battery and a current state of charge, a first model terminal voltage corresponding to the first measurement terminal voltage under the first operating condition indicator is determined, and a first voltage error is further determined; when the first operating condition indicator meets the target operating condition and the first voltage error is not within a reference voltage error range corresponding to the target operating condition, the current state of charge of the battery is calibrated based on the first voltage error and the reference voltage error range. In this way, on the one hand, since there is a specific corresponding relationship between the open circuit voltage (OCV) of the battery and the SOC, by introducing the equivalent circuit model of the battery, the voltage error between the battery terminal voltage calculated by the model and the actually measured battery terminal voltage can be used to reflect the deviation of the SOC; on the other hand, under the target operating conditions, if the SOC of the battery meets the target credibility condition, the error range of the model terminal voltage determined based on the equivalent circuit model will be within the reference voltage error range. In this way, by comparing the first operating condition indicator with the target operating condition, and comparing the first voltage error under the first operating condition indicator with the reference voltage error range under the target operating condition, it is possible to more accurately determine whether the current state of charge of the battery is credible, thereby more accurately identifying whether the current state of charge of the battery needs to be calibrated. In this way, when the first operating condition indicator meets the target operating condition and the first voltage error is not within the reference voltage error range corresponding to the target operating condition, by calibrating the current state of charge of the battery based on the first voltage error and the reference voltage error range, the chance of SOC correction can be increased, the SOC correction effect can be improved, and the accuracy of the state of charge calibration can be improved, thereby reducing the problem of battery overvoltage or undervoltage due to SOC deviation, and further improving the equipment performance of battery-supported electrical equipment.

[0008] In some embodiments, calibrating the current state of charge of the battery based on the first voltage error and the reference voltage error range includes: Based on the first voltage error and the reference voltage error range, a target voltage error range is determined; the upper limit of the target voltage error range is determined based on the difference between the first voltage error and the lower limit of the reference voltage error range, and the lower limit of the target voltage error range is determined based on the difference between the first voltage error and the upper limit of the reference voltage error range; Determining a target state of charge range of the battery based on the target voltage error range and the current state of charge of the battery; The current state of charge of the battery is calibrated based on the target state of charge range.

[0009] In the above embodiment, the target voltage error range is determined based on the first voltage error and the reference voltage error range; and the target state of charge range of the battery is determined based on the target voltage error range and the current state of charge of the battery; and the current state of charge of the battery is calibrated based on the target state of charge range. In this way, since the reference voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trustworthy condition, and the upper limit of the target voltage error range is determined based on the difference between the first voltage error and the lower limit of the reference voltage error range, and the lower limit of the target voltage error range is determined based on the difference between the first voltage error and the upper limit of the reference voltage error range, the target voltage error range can represent the error range of the open circuit voltage caused by the SOC deviation of the battery. Therefore, the target state of charge range determined based on the target voltage error range and the current state of charge of the battery can better reflect the real SOC of the battery, and then based on the target state of charge range, the accuracy of calibrating the current state of charge of the battery can be improved.

[0010] In some embodiments, determining a target state of charge range of the battery based on the target voltage error range and the current state of charge of the battery includes: Based on the current state of charge of the battery, query the first corresponding relationship to obtain an estimated value of the current open circuit voltage of the battery; the first corresponding relationship represents the corresponding relationship between the open circuit voltage and the state of charge of the battery; Determine a target open circuit voltage range of the battery based on the estimated value and the target voltage error range; Based on the target open circuit voltage range and the first corresponding relationship, a target state of charge range of the battery is determined.

[0011] In the above embodiment, based on the current state of charge of the battery, the first corresponding relationship is queried to obtain an estimated value of the current open circuit voltage of the battery; and based on the estimated value and the target voltage error range, the target open circuit voltage range of the battery is determined; and further based on the target open circuit voltage range and the first corresponding relationship, the target state of charge range of the battery is determined. In this way, based on the corresponding relationship between the open circuit voltage and the state of charge of the battery, the target state of charge range of the battery can be quickly and accurately determined based on the target voltage error range and the current state of charge of the battery, thereby improving the accuracy and efficiency of the battery SOC calibration.

[0012] In some embodiments, calibrating the current state of charge of the battery based on the target state of charge range includes: When the state of charge of the battery is greater than a first threshold, calibrating the state of charge of the battery to the first threshold; the first threshold includes an upper limit of a target state of charge range; When the state of charge of the battery is less than a second threshold, the state of charge of the battery is calibrated to the second threshold; the second threshold includes a lower limit of the target state of charge range.

[0013] In the above embodiment, the current state of charge of the battery is calibrated based on the maximum and minimum thresholds of the state of charge corresponding to the target state of charge range. In this way, the accuracy of the battery SOC calibration can be further improved by limiting the state of charge of the calibrated battery to within the target state of charge range.

[0014] In some embodiments, calibrating the current state of charge of the battery based on the target state of charge range includes: When the rate of change of the open circuit voltage of the battery with the state of charge within the target state of charge range exceeds a change rate threshold, the current state of charge of the battery is calibrated.

[0015] In the above embodiment, when the rate of change of the open circuit voltage of the battery with the state of charge exceeds the rate of change threshold within the target state of charge range, the current state of charge of the battery is calibrated. In this way, considering that the rate of change of the open circuit voltage of the battery with the state of charge does not exceed the rate of change threshold, the rate of change of the open circuit voltage with the state of charge is usually small (for example, the OCV corresponding to the state of charge of the battery is in the platform area). In this case, the upper and lower limits of the SOC are reversely deduced based on the upper and lower limits of the OCV and the corresponding relationship between SOC-OCV. There will be a large error, and the problem of inaccurate calibration is prone to occur. Therefore, when the rate of change of the open circuit voltage of the battery with the state of charge exceeds the rate of change threshold within the target state of charge range, the SOC is calibrated, which can reduce the inaccurate calibration caused by the OCV being in the platform area, and improve the accuracy and reference of the calibration result.

[0016] In some embodiments, obtaining a first measurement terminal voltage of a battery and a first operating condition indicator corresponding to the first measurement terminal voltage includes: Collecting the first measuring terminal voltages corresponding to the battery at multiple moments within the target state of charge change interval and the first operating condition indicators corresponding to each first measuring terminal voltage; Determining a first voltage error of a first model terminal voltage based on a first measurement terminal voltage includes: averaging the first measurement terminal voltages collected at multiple times within the target state of charge change interval to obtain an average measurement terminal voltage; averaging a plurality of first model terminal voltages respectively corresponding to a plurality of first measurement terminal voltages to obtain an average model terminal voltage; The difference between the average model terminal voltage and the average measurement terminal voltage is determined as a first voltage error.

[0017] In the above embodiment, the first measurement terminal voltages corresponding to different moments and the first operating condition indicators corresponding to the first measurement terminal voltages are collected multiple times within the target state of charge change interval; and the multiple first measurement terminal voltages collected within the target state of charge change interval and the first model terminal voltages corresponding to the multiple first measurement terminal voltages are averaged; the difference between the obtained average model terminal voltage and the average measurement terminal voltage is determined as the first voltage error. In this way, based on the average values ​​of the first measurement terminal voltage and the first model terminal voltage within the state of charge change interval, the influence of abnormal data on the determination of the first voltage error can be reduced, thereby improving the accuracy and reference of the first voltage error.

[0018] In some embodiments, the first operating condition indicator includes temperature and / or current multiplier, and the calibration method further includes at least one of the following: When the first operating condition indicator includes temperature and the minimum temperature within the target state of charge change interval is not less than a minimum temperature threshold, determining that the first operating condition indicator satisfies the target operating condition; When the first operating condition indicator includes a current magnification and the average current magnification within the target state of charge change interval is not greater than an average current magnification threshold, it is determined that the first operating condition indicator meets the target operating condition.

[0019] In this way, considering that there may be an abnormal decrease in battery temperature within the target state of charge change interval, determining that the minimum temperature among the temperatures corresponding to multiple moments within the target state of charge change interval is not less than the minimum temperature threshold can reduce the impact of abnormal low temperature data on determining whether the first operating condition indicator meets the target operating condition, and improve the accuracy and stability of determining that the first operating condition indicator meets the target operating condition. Considering that the current rate at different moments within the target state of charge change interval may fluctuate, determining that the average current rate within the target state of charge change interval is not greater than the average current rate threshold can reduce the impact of the fluctuation of the current rate at different moments on determining whether the first operating condition indicator meets the target operating condition, and improve the accuracy and stability of determining that the first operating condition indicator meets the target operating condition. At the same time, two different operating condition indicators can be combined to further improve the accuracy and stability of determining that the first operating condition indicator meets the target operating condition.

[0020] In some embodiments, the calibration method further comprises: Determine at least one candidate operating condition and a candidate voltage error range corresponding to each candidate operating condition; the candidate voltage error range represents an error range of a model terminal voltage determined based on an equivalent circuit model when the state of charge of the battery meets a target trustworthy condition; From at least one candidate operating condition, a target operating condition corresponding to a reference voltage error range is determined.

[0021] In the above embodiment, by determining at least one candidate operating condition and a candidate voltage error range corresponding to each candidate operating condition, a target operating condition corresponding to a reference voltage error range can be quickly and accurately determined from the at least one candidate operating condition.

[0022] In some embodiments, determining at least one candidate operating condition and a candidate voltage error range corresponding to the candidate operating condition includes: Acquire at least one second measurement terminal voltage of the battery during a target test, and a second operating condition indicator and a measured state of charge corresponding to each second measurement terminal voltage; For each second measurement terminal voltage, based on the equivalent circuit model and the corresponding measured state of charge, determine the second model terminal voltage of the battery under the corresponding second operating condition indicator, and determine the second voltage error of the second model terminal voltage based on the second measurement terminal voltage; Based on the second operating condition indicators corresponding to the voltages at each second measuring terminal and the corresponding second voltage errors, at least one candidate operating condition and a candidate voltage error range having a corresponding relationship are determined.

[0023] In the above embodiment, at least one second measurement terminal voltage collected during the target test process, and the second operating condition index and the measured charge state corresponding to each second measurement terminal voltage are used; the second model terminal voltage of the battery under the corresponding second operating condition index is determined, and the second voltage error of the second model terminal voltage is determined based on the second measurement terminal voltage; further based on the second operating condition index corresponding to each second measurement terminal voltage and the corresponding second voltage error, at least one candidate operating condition and a candidate voltage error range with a corresponding relationship are determined. In this way, based on the corresponding relationship between at least one second voltage error and the second operating condition index, the accuracy of finding the candidate operating condition and the corresponding candidate voltage error range can be improved, and the accuracy of determining the target operating condition from the candidate operating condition based on the reference voltage error range can be further improved.

[0024] The present application provides a state of charge calibration device, which includes: An acquisition module, used to acquire a first measurement terminal voltage of the battery and a first operating condition indicator corresponding to the first measurement terminal voltage; A first determination module, configured to determine a first model terminal voltage corresponding to a first operating condition indicator of the battery based on an equivalent circuit model of the battery and a current state of charge of the battery; A second determination module, configured to determine a first voltage error of a first model terminal voltage based on a first measurement terminal voltage; A calibration module is used to calibrate the current state of charge of the battery based on the first voltage error and the reference voltage error range when the first operating condition indicator meets the target operating condition and the first voltage error is not within the reference voltage error range corresponding to the target operating condition; the reference voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trustworthy condition.

[0025] An embodiment of the present application provides a computer-readable storage medium, which stores a computer program. The computer program can be executed by a processor to implement the above-mentioned state of charge calibration method.

[0026] An embodiment of the present application provides a computer program product, including a computer program or instructions, which, when executed by a processor, implements some or all of the steps in the above-mentioned state of charge calibration method.

[0027] An embodiment of the present application provides a battery system, which includes: at least one battery and a battery management system; the battery management system is used to implement some or all of the steps in the above-mentioned state of charge calibration method.

[0028] An embodiment of the present application provides an electrical device, which includes the above-mentioned battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1A A schematic diagram of a flow chart of a method for calibrating a state of charge provided in an embodiment of the present application; Figure 1B A schematic diagram of the structure of an equivalent circuit model provided in an embodiment of the present application; Figure 2 A schematic diagram of the implementation process of a charge state calibration method provided in an embodiment of the present application Figure 2 ; Figure 3 A schematic diagram of the composition structure of a charge state calibration device provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of a battery system provided in an embodiment of the present application; Figure 5 A schematic diagram of the composition structure of an electrical device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and technical features in the embodiments of the present application can be combined with each other, and the detailed description in the specific implementation method should be understood as an explanation of the purpose of the present application and should not be regarded as an improper limitation on the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in this application are intended to cover non-exclusive inclusions.

[0032] In the description of the embodiments of the present application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0033] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0034] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0035] Batteries are widely used as power and energy sources for electrical devices, but SOC deviations will gradually accumulate with increasing usage. If the accumulated SOC deviations are not corrected, it will cause unexpected phenomena such as overvoltage or undervoltage in the battery, thereby affecting the performance of the electrical devices supported by the battery.

[0036] The present application embodiment provides a method for calibrating the state of charge, such as Figure 1A As shown, the calibration method may include the following steps S101 to S104: Step S101, obtaining a first measurement terminal voltage of a battery and a first operating condition indicator corresponding to the first measurement terminal voltage.

[0037] Here, the type of battery may include but is not limited to at least one of a lithium-ion battery, a zinc-manganese battery, a lead-acid battery, and the like.

[0038] The first measurement terminal voltage may be an actual terminal voltage obtained by measuring the battery.

[0039] The first operating condition indicator can be used to characterize the working environment and / or working state of the battery at the first measuring terminal voltage, and can be an operating condition indicator collected when measuring the first measuring terminal voltage; wherein the operating condition indicator may include but is not limited to at least one of current, current rate, temperature, humidity, etc.

[0040] In some embodiments, the first measurement terminal voltage of the battery and the first operating condition indicator corresponding to the first measurement terminal voltage can be obtained during the use of the battery; the first measurement terminal voltage of the battery and the first operating condition indicator corresponding to the first measurement terminal voltage can also be obtained when the battery is in a non-use state (for example, a static state).

[0041] In some embodiments, the first measurement terminal voltage of the battery and the first operating condition indicator corresponding to the first measurement terminal voltage can be obtained in real time; the first measurement terminal voltage of the battery and the first operating condition indicator corresponding to the first measurement terminal voltage can also be obtained periodically based on a target time interval.

[0042] Step S102: determining a first model terminal voltage corresponding to the battery under a first operating condition indicator based on an equivalent circuit model of the battery and the current state of charge of the battery.

[0043] Here, the equivalent circuit model of the battery can be used as an open-loop model of the battery to simulate the dynamic characteristics of the battery and reflect the voltage change characteristics of the battery during the charging and discharging process, such as ohmic voltage drop, electrochemical polarization, and concentration polarization. In implementation, the equivalent circuit model of the battery can be any suitable open-loop model, which is not limited in the embodiments of the present application.

[0044] In some embodiments, the equivalent circuit model of the battery may include, but is not limited to, at least one of a first-order resistance-capacitance (RC) equivalent circuit model, a second-order RC equivalent circuit model, and the like.

[0045] The first model terminal voltage may be a battery terminal voltage estimated under a first operating condition indicator based on model parameters of an equivalent circuit model and a current state of charge of the battery; wherein the model parameters may include but are not limited to at least one of a battery open circuit voltage, a battery equivalent internal resistance, a polarization resistance, a voltage of a polarization resistance, and the like.

[0046] In some embodiments, based on the current state of charge of the battery, a first correspondence between the open circuit voltage of the battery and the state of charge can be queried to obtain the open circuit voltage corresponding to the current state of charge; after establishing an equivalent circuit model of the battery, the first operating condition indicator and the open circuit voltage corresponding to the current state of charge are input into the equivalent circuit model to obtain the first model terminal voltage.

[0047] For example, Figure 1BAs shown, taking the second-order RC equivalent circuit model 10 as an example, the equivalent circuit model 10 includes a battery equivalent internal resistance 11, polarization resistors 12 and 13, a polarization capacitor 14 corresponding to the polarization resistor 12, a polarization capacitor 15 corresponding to the polarization resistor 13, an equivalent voltage source 16, a battery positive electrode 17, and a battery negative electrode 18.

[0048] According to Kirchhoff's law, the input-output relationship of the equivalent circuit model 10 can be seen in formulas (1) to (3): (1); (2); (3); in, U t is the first model terminal voltage corresponding to the equivalent circuit model 10 between the battery positive electrode 17 and the battery negative electrode 18, U OC is the open circuit voltage of the equivalent voltage source 16, that is, the open circuit voltage of the battery, R 0 is the internal resistance value of the battery equivalent internal resistance 11, U D1 and U D2 are the voltage values ​​of polarization resistors 12 and 13 respectively, R D1 and R D2 are the resistance values ​​of polarization resistors 12 and 13 respectively, C D1 and C D2 are the capacitance values ​​of polarized capacitors 14 and 15 respectively, i L is the current value. U OC The state of charge may be determined based on the current state of charge of the battery and the corresponding relationship between the state of charge of the battery and the open circuit voltage.

[0049] It can be understood that based on formula (1), when there is no deviation in SOC, U OC Without error, the voltage at the first model terminal of the equivalent circuit model 10 is U t The error comes from U D1 The error, U D2 errors, and / or i L R 0 The error ofU D1 The error, U D2 The error, and i L R 0 The error is usually related to operating conditions such as current rate and / or temperature.

[0050] In some implementations, the model parameters of the equivalent circuit model may be identified offline by using a target optimization algorithm through test experiments.

[0051] For example, the least square method can be used to analyze the Figure 1B The model parameter U of the equivalent circuit model 10 in OC , R 0 , R D1 , U D1 , R D2 and U D2 The fitting is performed to complete the off-line identification process of the model parameters of the equivalent circuit model 10 .

[0052] The current state of charge of the battery can be estimated based on the target parameters of the battery at the current moment; wherein the target parameters may include but are not limited to at least one of the open circuit voltage of the battery, the current of the battery, the discharge capacity of the battery, the rated capacity of the battery, etc.

[0053] For example, the open circuit voltage of the battery at the current moment can be obtained by measuring, and the current state of charge of the battery can be estimated by the open circuit voltage method.

[0054] For example, the current of the battery at the current moment and at historical moments can be measured, and the current state of charge of the battery can be estimated by the ampere-hour integration method.

[0055] In some embodiments, the current state of charge of the battery may be estimated by a management component of the battery, for example, by a battery management system (BMS).

[0056] Step S103: determining a first voltage error of a first model terminal voltage based on the first measurement terminal voltage.

[0057] Here, the first voltage error may represent an error between a battery terminal voltage calculated by an equivalent circuit model and a battery terminal voltage actually measured under a first operating condition indicator.

[0058] In some implementations, the first voltage error may be determined based on a difference between the first model terminal voltage and the first measurement terminal voltage.

[0059] For example, the first voltage error may be a difference between the first model terminal voltage and the first measurement terminal voltage.

[0060] For another example, the first voltage error may be an average value of differences between the first model terminal voltage and the corresponding first measurement terminal voltage at multiple moments within the target time period.

[0061] For another example, the first voltage error may be a difference between an average model terminal voltage obtained by averaging first model terminal voltages at multiple moments within the target duration and an average measurement terminal voltage obtained by averaging first measurement terminal voltages at corresponding multiple moments.

[0062] For example, the process of determining the first voltage error Q may refer to formula (4): (4); Among them, V t1 is the voltage at the first model terminal, V t2 is the voltage at the first measuring terminal.

[0063] Step S104, when the first operating condition indicator meets the target operating condition and the first voltage error is not within the reference voltage error range corresponding to the target operating condition, calibrate the current state of charge of the battery based on the first voltage error; the reference voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trustworthy condition.

[0064] Here, the target trust condition can indicate that the state of charge of the battery is trustworthy, and the model terminal voltage corresponding to the equivalent circuit model determined based on the state of charge is trustworthy, that is, under the target operating conditions corresponding to the reference voltage error range, the error range of the model terminal voltage of the battery is within the reference voltage error range.

[0065] In some implementations, it may be determined that the current state of charge meets the target trustworthy condition when the absolute value of the difference between the current state of charge of the battery and the corresponding actual state of charge is less than an absolute value threshold.

[0066] For example, when the current state of charge of the battery is 28% and the actual state of charge is 25%, the absolute value of the difference between the current state of charge and the corresponding actual state of charge is 3%, which is less than the absolute value threshold of 5%, then the current state of charge meets the target trust condition.

[0067] The target operating condition may include preset conditions corresponding to one or more operating condition indicators, for example, may include but is not limited to at least one of the temperature satisfying the target temperature condition, the current satisfying the target current condition, the humidity satisfying the target humidity condition, etc.

[0068] In some implementations, the target operating conditions are different, and the corresponding reference voltage error ranges may be different.

[0069] It can be understood that when the first operating condition index meets the target operating condition, the error range of the model terminal voltage of the battery should be within the reference voltage error range. If the first voltage error is not within the reference voltage error range corresponding to the target operating condition, it can be explained that there is a deviation in the SOC of the battery, resulting in a deviation between the OCV determined based on the SOC and the actual OCV, which further leads to inaccurate model terminal voltage, so that the error range of the model terminal voltage determined based on the equivalent circuit model is not within the reference voltage error range. In this case, calibrating the SOC of the battery at the current moment can improve the accuracy of the battery SOC.

[0070] Exemplarily, the reference voltage error range may include but is not limited to [-30mV, 30mV], [-25mV, 25mV], [-20mV, 20mV], etc.

[0071] In some implementations, the step S104 of calibrating the current state of charge of the battery based on the first voltage error may include the following steps S1041: Step S1041: calibrate the current state of charge of the battery based on the first voltage error and the reference voltage error range.

[0072] Here, since the reference voltage error range can characterize the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery under the target operating condition meets the target trust condition, and the first operating condition indicator corresponding to the first voltage error meets the target operating condition, therefore, a comprehensive analysis of the first voltage error and the reference voltage error range can obtain the voltage error range caused by the SOC deviation of the battery, thereby reflecting the SOC deviation of the battery. Therefore, based on the first voltage error and the reference voltage error range, the current state of charge of the battery can be calibrated.

[0073] In some implementations, the current state of charge of the battery may be calibrated at least once based on the first voltage error and the reference voltage error range, so that a new first voltage error determined based on the calibrated SOC is within the reference voltage error range.

[0074] In an embodiment of the present application, a first measurement terminal voltage of the battery and a corresponding first operating condition indicator are obtained; based on an equivalent circuit model of the battery and a current state of charge, a first model terminal voltage corresponding to the first measurement terminal voltage under the first operating condition indicator is determined, and a first voltage error is further determined; when the first operating condition indicator meets the target operating condition and the first voltage error is not within a reference voltage error range corresponding to the target operating condition, the current state of charge of the battery is calibrated based on the first voltage error and the reference voltage error range. In this way, on the one hand, since there is a specific corresponding relationship between the open circuit voltage (OCV) of the battery and the SOC, by introducing the equivalent circuit model of the battery, the voltage error between the battery terminal voltage calculated by the model and the actually measured battery terminal voltage can be used to reflect the deviation of the SOC; on the other hand, under the target operating conditions, if the SOC of the battery meets the target credibility condition, the error range of the model terminal voltage determined based on the equivalent circuit model will be within the reference voltage error range. In this way, by comparing the first operating condition indicator with the target operating condition, and comparing the first voltage error under the first operating condition indicator with the reference voltage error range under the target operating condition, it is possible to more accurately determine whether the current state of charge of the battery is credible, thereby more accurately identifying whether the current state of charge of the battery needs to be calibrated. In this way, when the first operating condition indicator meets the target operating condition and the first voltage error is not within the reference voltage error range corresponding to the target operating condition, by calibrating the current state of charge of the battery based on the first voltage error and the reference voltage error range, the chance of SOC correction can be increased, the SOC correction effect can be improved, and the accuracy of the state of charge calibration can be improved, thereby reducing the problem of battery overvoltage or undervoltage due to SOC deviation, and further improving the equipment performance of battery-supported electrical equipment.

[0075] In some embodiments, the step S104 described above of calibrating the current state of charge of the battery based on the first voltage error and the reference voltage error range may include the following steps S201 to S203: Step S201, determine a target voltage error range based on a first voltage error and a reference voltage error range; the upper limit of the target voltage error range is determined based on the difference between the first voltage error and the lower limit of the reference voltage error range, and the lower limit of the target voltage error range is determined based on the difference between the first voltage error and the upper limit of the reference voltage error range.

[0076] Here, when there is a deviation in SOC, the first voltage error can be determined jointly by the voltage error of the model terminal voltage when the state of charge of the battery meets the target trust condition and the voltage error of the open circuit voltage caused by the SOC deviation (i.e., not meeting the target trust condition); wherein, the voltage error of the model terminal voltage when the state of charge of the battery meets the target trust condition can be determined based on the voltage error of the polarization resistance and / or the voltage error of the equivalent internal resistance of the battery.

[0077] The target voltage error range may represent the range of the voltage error of the open circuit voltage caused by the SOC deviation.

[0078] Exemplarily, the first voltage error Q and the voltage error Q of the model terminal voltage when the state of charge of the battery meets the target trust condition 1 And the voltage error Q caused by SOC deviation 2 The relationship between can be seen in formula (5): (5); Among them, Q 1 The value range of is the reference voltage error range, that is, when the battery state of charge meets the target trust condition, the voltage error of the model terminal voltage is not less than the lower limit of the reference voltage error range and not greater than the upper limit of the reference voltage error range; Therefore, when the first voltage error Q is determined and the reference voltage error range (ie, the value range of Q1 ) is determined, the target voltage error range (ie, the value range of Q2 ) can also be determined.

[0079] Step S202: Determine a target state of charge range of the battery based on the target voltage error range and the current state of charge of the battery.

[0080] Here, the target state of charge range may represent the range of the actual SOC under the first operating condition indicator.

[0081] The target voltage error range can represent the range of the difference between the OCV corresponding to the current estimated SOC (ie, the current state of charge) and the OCV corresponding to the actual SOC.

[0082] For example, formula (5) can also be expressed as formula (6): (6); Among them, V OCV1 is the OCV corresponding to the current estimated SOC, V OCV2 is the OCV corresponding to the actual SOC.

[0083] Since the target voltage error range can characterize the error range between the OCV corresponding to the current state of charge and the OCV corresponding to the actual SOC, the OCV range corresponding to the actual SOC can be determined based on the target voltage error range and the OCV corresponding to the current state of charge. Further, using the correspondence between the battery's OCV and SOC, the battery's target state of charge range can be determined.

[0084] For example, within the target voltage error range (i.e., Q 2 If the value range of V OCV1 -V OCV2 The value range of can also be determined, and further we can get V OCV2 The upper limit is V OCV1 With Q 2 The difference between the lower limit, V OCV2 The lower limit is V OCV1 With Q 2 The difference between the upper limit and the lower limit can be further used to determine V by using the corresponding relationship between the battery's OCV and SOC. OCV2 The upper limit of the actual SOC corresponds to the upper limit of V OCV2 The lower limit of corresponds to the lower limit of the actual SOC (i.e., the target state of charge range).

[0085] Step S203: calibrate the current state of charge of the battery based on the target state of charge range.

[0086] Here, when the current state of charge of the battery exceeds the target state of charge range, the current state of charge of the battery may be calibrated.

[0087] For example, when the current state of charge of the battery is within the target state of charge range, the current state of charge of the battery may not be corrected.

[0088] In the embodiment of the present application, the target voltage error range is determined based on the first voltage error and the reference voltage error range; and the target state of charge range of the battery is determined based on the target voltage error range and the current state of charge of the battery; and the current state of charge of the battery is calibrated based on the target state of charge range. In this way, since the reference voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trust condition, and the upper limit of the target voltage error range is determined based on the difference between the first voltage error and the lower limit of the reference voltage error range, and the lower limit of the target voltage error range is determined based on the difference between the first voltage error and the upper limit of the reference voltage error range, therefore, the target voltage error range can represent the error range of the open circuit voltage caused by the SOC deviation of the battery. Therefore, the target state of charge range determined based on the target voltage error range and the current state of charge of the battery can better reflect the real SOC of the battery, and then based on the target state of charge range, the accuracy of calibrating the current state of charge of the battery can be improved.

[0089] In some embodiments, the above step S202 may include the following steps S301 to S303: Step S301: Based on the current state of charge of the battery, query a first corresponding relationship to obtain an estimated value of the current open circuit voltage of the battery; the first corresponding relationship represents the corresponding relationship between the open circuit voltage and the state of charge of the battery.

[0090] Here, querying the first corresponding relationship may include but is not limited to querying at least one of a table, a set, a function, a curve, etc. that can characterize the corresponding relationship between the open circuit voltage and the state of charge of the battery.

[0091] The estimated value of the current open circuit voltage of the battery may correspond to the OCV corresponding to the currently estimated SOC in the above-mentioned state of charge calibration method.

[0092] Step S302: Determine a target open circuit voltage range of the battery based on the estimated value and the target voltage error range.

[0093] Here, the target open circuit voltage range may correspond to the OCV range corresponding to the actual SOC in the above-mentioned state of charge calibration method.

[0094] For example, based on formula (4) and formula (6), formula (7) can be obtained: (7); It can be understood that when the estimated value is determined, that is, the OCV corresponding to the current estimated SOC is determined, the target voltage error range is determined, the first model terminal voltage and the first measurement terminal voltage are determined, and the battery state of charge meets the target trust condition and the voltage error of the model terminal voltage is within the reference voltage error range, the OCV range corresponding to the actual SOC, that is, the target open circuit voltage range, can be determined according to formula (7).

[0095] Step S303: determining a target state of charge range of the battery based on the target open circuit voltage range and the first corresponding relationship.

[0096] Here, the state of charge corresponding to the open circuit voltage within the target open circuit voltage range may be determined based on the first corresponding relationship, and the target state of charge range may be further determined based on the state of charge corresponding to the open circuit voltage within the target open circuit voltage range.

[0097] In the embodiment of the present application, based on the current state of charge of the battery, the first corresponding relationship is queried to obtain an estimated value of the current open circuit voltage of the battery; and based on the estimated value and the target voltage error range, the target open circuit voltage range of the battery is determined; and further based on the target open circuit voltage range and the first corresponding relationship, the target state of charge range of the battery is determined. In this way, based on the corresponding relationship between the open circuit voltage and the state of charge of the battery, the target state of charge range of the battery can be quickly and accurately determined based on the target voltage error range and the current state of charge of the battery, thereby improving the accuracy and efficiency of the battery SOC calibration.

[0098] In some embodiments, the above step S203 may include the following steps S401 to S402: Step S401: When the current state of charge of the battery is greater than a first threshold, calibrate the state of charge of the battery to the first threshold; the first threshold includes an upper limit of a target state of charge range.

[0099] Here, the current state of charge of the battery being greater than the first threshold may indicate that the current state of charge of the battery is falsely higher than the state of charge credible range. Therefore, the state of charge of the battery needs to be calibrated to the credible range, that is, calibrated to the upper limit of the credible range.

[0100] For example, based on the above formula (7) and the target voltage error range, formula (8) can be obtained: (8); Among them, Q 1max is the upper limit of Q1, V OCV2max is the upper limit of the OCV corresponding to the real SOC. After determining the upper limit of the OCV corresponding to the real SOC, the upper limit of the target state of charge range, that is, the first threshold, can be determined based on the corresponding relationship between SOC and OCV.

[0101] Step S402: When the current state of charge of the battery is less than a second threshold, calibrate the state of charge of the battery to the second threshold; the second threshold includes a lower limit of the target state of charge range.

[0102] Here, the current state of charge of the battery being less than the second threshold value may indicate that the current state of charge of the battery is falsely lower than the credible range of the state of charge. Therefore, the state of charge of the battery needs to be calibrated to the credible range, that is, calibrated to the lower limit of the credible range.

[0103] For example, based on the above formula (7) and the target voltage error range, formula (9) can be obtained: (9); Among them, Q 1min is the lower limit of Q1, V OCV2min is the lower limit of the OCV corresponding to the actual SOC. After determining the lower limit of the OCV corresponding to the actual SOC, the lower limit of the target state of charge range, that is, the second threshold value, can be determined based on the corresponding relationship between SOC and OCV.

[0104] In the embodiment of the present application, the current state of charge of the battery is calibrated based on the maximum and minimum thresholds of the state of charge corresponding to the target state of charge range. In this way, the accuracy of the battery SOC calibration can be further improved by limiting the state of charge of the calibrated battery to within the target state of charge range.

[0105] In some embodiments, the above step S203 may include the following step S501: Step S501: When the rate of change of the open circuit voltage of the battery with the state of charge exceeds a change rate threshold within a target state of charge range, calibrate the current state of charge of the battery.

[0106] In this way, the rate of change of the open circuit voltage with the state of charge exceeds the rate of change threshold, which can indicate that the OCV of the battery changes significantly with the change of SOC. Considering that the first model terminal voltage is determined based on the state of charge of the battery, when the OCV does not change significantly with the change of SOC, the accuracy of the first model terminal voltage determined based on the OCV will be reduced, and the accuracy of judging whether to calibrate the current state of charge based on the first voltage error corresponding to the first model terminal voltage will be further reduced.

[0107] Exemplarily, when the rate of change of the open circuit voltage of the battery with the state of charge exceeds a change rate threshold, the target state of charge range may correspond to at least one of SOC less than 30%, SOC greater than 60% and less than 70%, SOC greater than 95%, etc.

[0108] In the embodiment of the present application, when the rate of change of the open circuit voltage of the battery with the state of charge exceeds the rate of change threshold within the target state of charge range, the current state of charge of the battery is calibrated. In this way, considering that the rate of change of the open circuit voltage of the battery with the state of charge does not exceed the rate of change threshold, the rate of change of the open circuit voltage with the state of charge is usually small (for example, the OCV corresponding to the state of charge of the battery is in the platform area). In this case, the upper and lower limits of the SOC are reversely deduced based on the upper and lower limits of the OCV and the corresponding relationship between SOC-OCV. There will be a large error, and the problem of inaccurate calibration is prone to occur. Therefore, when the rate of change of the open circuit voltage of the battery with the state of charge exceeds the rate of change threshold within the target state of charge range, the SOC is calibrated, which can reduce the inaccurate calibration caused by the OCV being in the platform area, and improve the accuracy and reference of the calibration result.

[0109] In some embodiments, the above step S101 may include the following step S601: Step S601: collecting first measurement terminal voltages corresponding to a plurality of moments in a target state of charge variation interval of the battery and first operating condition indicators corresponding to each first measurement terminal voltage.

[0110] Here, the target state of charge change interval may be an interval in which the state of charge of the battery changes during or after use.

[0111] For example, if the SOC of the battery changes from 15% to 24% during or after use, the target state of charge change interval may include the complete range of the SOC change from 15% to 24%, that is, a 9% change interval.

[0112] For another example, if the SOC of the battery changes from 15% to 24% during or after use, the target state of charge change interval may include every 3% change interval in the process of the SOC changing from 15% to 24%, which may include but is not limited to at least one of the interval segments of 15% to 18%, 16% to 19%, 18% to 21%, 21% to 24%, etc.

[0113] The above step S103 may include the following steps S602 to S604: Step S602 , averaging the first measurement terminal voltages collected at multiple times within the target state of charge variation interval to obtain an average measurement terminal voltage.

[0114] In some implementations, the first measurement terminal voltage may be collected multiple times according to the same or different time intervals.

[0115] Step S603 , averaging the plurality of first model terminal voltages corresponding to the plurality of first measurement terminal voltages to obtain an average model terminal voltage.

[0116] Step S604: determine the difference between the average model terminal voltage and the average measurement terminal voltage as a first voltage error.

[0117] It can be understood that the “(V t1 –V t2 )" can be replaced by the first voltage error obtained in step S604 based on the difference between the average model terminal voltage and the average measurement terminal voltage.

[0118] In the embodiment of the present application, the first measurement terminal voltage corresponding to different moments and the first operating condition index corresponding to each first measurement terminal voltage are collected multiple times within the target state of charge change interval; and the multiple first measurement terminal voltages collected within the target state of charge change interval and the first model terminal voltages corresponding to the multiple first measurement terminal voltages are averaged; the difference between the obtained average model terminal voltage and the average measurement terminal voltage is determined as the first voltage error. In this way, based on the average value of the first measurement terminal voltage and the first model terminal voltage within the state of charge change interval, the influence of abnormal data on the determination of the first voltage error can be reduced, and the accuracy and reference of the first voltage error can be improved.

[0119] In some embodiments, the first operating condition indicator includes temperature and / or current rate, and the state of charge calibration method may further include at least one of the following steps S701 to S702: Step S701: when the first operating condition indicator includes temperature and the minimum temperature within the target state of charge variation interval is not less than a minimum temperature threshold, determine that the first operating condition indicator satisfies the target operating condition.

[0120] Here, taking into account the possibility of an abnormal drop in battery temperature within the target state of charge change range, determining that the minimum temperature among the temperatures corresponding to multiple moments within the target state of charge change range is not less than the minimum temperature threshold can reduce the impact of abnormally low temperature data on determining whether the first operating condition indicator meets the target operating condition, and improve the accuracy and stability of determining whether the first operating condition indicator meets the target operating condition.

[0121] Step S702: When the first operating condition indicator includes a current multiplier and the average current multiplier within the target state of charge variation interval is not greater than an average current multiplier threshold, determine that the first operating condition indicator satisfies the target operating condition.

[0122] Here, the current rate may be an operating condition indicator that characterizes the charging and discharging capabilities of the battery.

[0123] In some implementations, the current rate may be determined based on the current and rated capacity of the battery.

[0124] The average current multiplier may be the average value of the current multipliers collected at multiple times within the target state of charge change interval. Taking into account that the current multiplier at different times within the target state of charge change interval may fluctuate, determining that the average current multiplier within the target state of charge change interval is not greater than the average current multiplier threshold can reduce the impact of the fluctuation of the current multiplier at different times on the judgment of whether the first operating condition indicator meets the target operating condition, thereby improving the accuracy and stability of determining whether the first operating condition indicator meets the target operating condition.

[0125] It is understandable that the above-mentioned state of charge calibration method may also include determining that the first operating condition indicator meets the target operating condition when the first operating condition indicator includes temperature and current magnification, and the minimum temperature within the target state of charge change interval is not less than the minimum temperature threshold, and the average current magnification within the target state of charge change interval is not greater than the average current magnification threshold. In this way, the accuracy and stability of determining that the first operating condition indicator meets the target operating condition can be further improved by combining two different operating condition indicators.

[0126] In some embodiments, the above-mentioned state of charge calibration method may further include the following steps S801 to S802: Step S801, determining at least one candidate operating condition and a candidate voltage error range corresponding to each candidate operating condition; the candidate voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the battery state of charge meets the target trust condition.

[0127] In some embodiments, the operation data of the electrical equipment in different scenarios can be collected by performing usage tests on the electrical equipment in advance; wherein the operation data may include but is not limited to current, current rate, voltage, temperature, SOC, etc.

[0128] For example, actual vehicle tests can be conducted on vehicles using batteries to collect operating data of the vehicles in different scenarios such as high-speed conditions and urban conditions; based on the operating data corresponding to each scenario, the model terminal voltage determined based on the equivalent circuit model in each scenario is determined; based on the measurement terminal voltage corresponding to each scenario, the voltage error of the model terminal voltage in each scenario is determined; based on the operating data corresponding to each scenario, operating conditions in which the voltage error of the model terminal voltage is within a preset threshold range are determined as candidate operating conditions; the range of the voltage error of the model terminal voltage corresponding to the operating data under the candidate operating conditions is determined as the candidate voltage error range corresponding to the candidate operating condition.

[0129] Step S802: Determine a target operating condition corresponding to a reference voltage error range from at least one candidate operating condition.

[0130] Here, based on the correspondence between the candidate operating conditions and the corresponding candidate voltage error ranges, the candidate operating condition corresponding to the candidate voltage error range that is the same as the reference voltage error range may be determined as the target operating condition.

[0131] In an embodiment of the present application, by determining at least one candidate operating condition and a candidate voltage error range corresponding to each candidate operating condition, a target operating condition corresponding to a reference voltage error range can be quickly and accurately determined from at least one candidate operating condition.

[0132] In some embodiments, the above step S801 may include the following steps S901 to S903: Step S901, obtaining at least one second measurement terminal voltage of the battery during a target test, and a second operating condition indicator and a measured state of charge corresponding to each second measurement terminal voltage.

[0133] Here, the target test process may include a usage test process of the electric device.

[0134] In some embodiments, during the target test process, the battery may be in a used state or in a non-used state.

[0135] The second operating condition indicator may be used to characterize the operating environment and / or operating state of the battery at the second measuring terminal voltage, and may be an operating condition indicator acquired when measuring the second measuring terminal voltage.

[0136] The measured state of charge may be the state of charge of the battery acquired when measuring the voltage of the second measuring terminal.

[0137] Step S902: for each second measurement terminal voltage, determine the second model terminal voltage of the battery under the corresponding second operating condition indicator based on the equivalent circuit model and the corresponding measured state of charge, and determine the second voltage error of the second model terminal voltage based on the second measurement terminal voltage.

[0138] Here, the second model terminal voltage may be a battery terminal voltage estimated based on model parameters of the equivalent circuit model and the state of charge of the battery under the second operating condition indicator.

[0139] For example, the process of determining the second voltage error Q' may refer to formula (10): (10); Among them, V t3 is the voltage at the second model terminal, V t4 is the voltage at the second measuring terminal.

[0140] Step S903: Based on the second operating condition indicators corresponding to the second measuring terminal voltages and the corresponding second voltage errors, at least one candidate operating condition and a candidate voltage error range having a corresponding relationship are determined.

[0141] Here, the second voltage error can be screened to determine the second operating condition indicator corresponding to the second voltage error within the first voltage error range as the candidate operating condition, and the first voltage error range can be determined as the candidate voltage error range corresponding to the candidate operating condition.

[0142] For example, the second operating condition indicators corresponding to the second voltage errors when at least one second voltage error is in the range of [-30mV, 30mV] can be sorted into candidate operating conditions. For example, when the second voltage error is in the range of [-30mV, 30mV], the minimum temperature in each second operating condition indicator is greater than 30 degrees, then when the candidate voltage error range is [-30mV, 30mV], the corresponding candidate operating condition may be that the minimum temperature is greater than 30 degrees.

[0143] In the embodiment of the present application, at least one second measurement terminal voltage collected during the target test process, and the second operating condition index and the measured charge state corresponding to each second measurement terminal voltage are used; the second model terminal voltage of the battery under the corresponding second operating condition index is determined, and the second voltage error of the second model terminal voltage is determined based on the second measurement terminal voltage; further based on the second operating condition index corresponding to each second measurement terminal voltage and the corresponding second voltage error, at least one candidate operating condition and a candidate voltage error range with a corresponding relationship are determined. In this way, based on the corresponding relationship between at least one second voltage error and the second operating condition index, the accuracy of finding the candidate operating condition and the corresponding candidate voltage error range can be improved, and the accuracy of determining the target operating condition from the candidate operating condition based on the reference voltage error range can be further improved.

[0144] Lithium iron phosphate (LFP) batteries have become an ideal power and energy source for electric vehicles due to their long life, good safety performance and low cost. However, LFP batteries have the problem that the change with the state of charge is not obvious when the open circuit voltage is in the platform area, and it is difficult to accurately estimate the state of charge when the open circuit voltage is in the platform area.

[0145] Furthermore, as the battery is used, the SOC deviation will gradually accumulate. If the long-term accumulated SOC deviation is not corrected, it may cause the battery to have undesirable phenomena such as overvoltage or undervoltage.

[0146] On this basis, the embodiment of the present application provides a method for calibrating the state of charge, and takes the scenario of calibrating the state of charge of a lithium iron phosphate battery as an example to illustrate the method for calibrating the state of charge provided by the embodiment of the present application. Figure 2 As shown, the charge state calibration method includes the following steps S1001 to S1006: Step S1001, establishing a model for a lithium iron phosphate battery.

[0147] Here, an open-loop model is established for the lithium iron phosphate battery.

[0148] In implementation, the model may include a second order RC equivalent circuit model.

[0149] Step S1002: Through OCV test experiments and pulse current test experiments, an optimization algorithm is used to complete the offline parameter identification process.

[0150] Step S1003: Screen out candidate operating conditions whose second voltage error is within a candidate voltage error range by trying multiple operating condition combinations.

[0151] For example, the battery current I can be collected in high-speed conditions, urban conditions, and other scenarios through actual vehicle testing of a car using the battery. t0 to I tn , voltage U t0 toU tn , Temperature T 0 To T n and SOC 0 To SOC n and other data; taking the current, temperature, SOC and other parameters as the input of the model in step S1001, and taking the calculated model terminal voltage as the output, the calculation process can refer to formula (1), wherein the calculated model terminal voltage can correspond to the second model terminal voltage in the above-mentioned state of charge calibration method; calculating the second voltage error within the 3% SOC change interval for each 3% SOC change interval, wherein the second voltage error is determined based on the average value of the second measurement terminal voltage collected at multiple moments and the difference between the average values ​​of the second model terminal voltages corresponding to each second measurement terminal voltage; and counting the second operating condition indicators within the 3% SOC change interval, such as the average current ratio of the 3% SOC change segment, the minimum temperature of the 3% SOC change segment, etc.; by combining multiple second operating condition indicators with the second voltage error within [-30mV, 30mV], screening out candidate operating conditions, such as the average current ratio is less than 0.5C and the minimum temperature is greater than 30 degrees, and [-30mV, 30mV] is used as the candidate voltage error range corresponding to the candidate operating condition.

[0152] Step S1004: during the operation of the battery, determine a first operating condition indicator and a corresponding first voltage error.

[0153] Exemplarily, during the operation of the battery, the average measurement terminal voltage and the average model terminal voltage in each 3% SOC change interval can be calculated to obtain the first voltage error in each 3% SOC change interval, and the average current rate and minimum temperature corresponding to each 3% SOC change interval can be determined; when the average current rate corresponding to the 3% SOC change interval is less than 0.5C and the minimum temperature is greater than 30 degrees, it can be determined that the first voltage error in the 3% SOC change interval is in [-30mV, 30mV], that is, within the reference voltage error range.

[0154] Here, when the first voltage error is not within the reference voltage error range, steps S1005 to S1006 are performed.

[0155] Step S1005: Calculate the target open circuit voltage range.

[0156] Step S1006: based on the variation curve between OCV and SOC and the target open circuit voltage range, correct the current state of charge of the battery.

[0157] Here, the variation curve between OCV and SOC may correspond to the first corresponding relationship in the above-mentioned state of charge calibration method.

[0158] For example, when the current SOC of the battery is 30% and the OCV corresponding to the current SOC is 3257mV, the average model terminal voltage is 3104mV, and the corresponding average measurement terminal voltage is 3051mV. The upper limit of the OCV corresponding to the unbiased SOC calculated by Formula 8 is 3234mV, and the lower limit of the OCV corresponding to the unbiased SOC is 3174mV. The upper limit of the target state of charge range obtained from the OCV-SOC curve is 24%, and the lower limit of the target state of charge range is 6%. Since the current SOC is greater than 24%, the SOC is corrected to 24%.

[0159] In the embodiment of the present application, during the operation of the battery, the first operating condition index and the corresponding first voltage error are determined; when the first voltage error is not within the reference voltage error range corresponding to the first operating condition index, the current state of charge of the battery is corrected based on the change curve between OCV and SOC and the target open circuit voltage range. In this way, the state of charge of the battery can be calibrated when there is a deviation such as falsely high or falsely low current state of charge of the battery, reducing the problem of overvoltage or undervoltage of the battery due to SOC deviation, and further improving the equipment performance of the power-consuming equipment supported by the battery.

[0160] The present application embodiment provides a charge state calibration device, such as Figure 3 As shown, the state of charge calibration device 30 includes: An acquisition module 31 is used to acquire a first measurement terminal voltage of a battery and a first operating condition indicator corresponding to the first measurement terminal voltage; A first determining module 32, configured to determine a first model terminal voltage corresponding to the battery under the first operating condition indicator based on an equivalent circuit model of the battery and a current state of charge of the battery; A second determining module 33, configured to determine a first voltage error of the first model terminal voltage based on the first measurement terminal voltage; The calibration module 34 is used to calibrate the current state of charge of the battery based on the first voltage error and the reference voltage error range when the first operating condition indicator meets the target operating condition and the first voltage error is not within the reference voltage error range corresponding to the target operating condition; the reference voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trustworthy condition.

[0161] In some embodiments, the calibration module can also be used to: determine a target voltage error range based on the first voltage error and the reference voltage error range; the upper limit of the target voltage error range is determined based on the difference between the first voltage error and the lower limit of the reference voltage error range, and the lower limit of the target voltage error range is determined based on the difference between the first voltage error and the upper limit of the reference voltage error range; determine the target state of charge range of the battery based on the target voltage error range and the current state of charge of the battery; and calibrate the current state of charge of the battery based on the target state of charge range.

[0162] In some embodiments, the calibration module can also be used to: based on the current state of charge of the battery, query a first corresponding relationship to obtain an estimated value of the current open circuit voltage of the battery; the first corresponding relationship characterizes the correspondence between the open circuit voltage and the state of charge of the battery; based on the estimated value and the target voltage error range, determine the target open circuit voltage range of the battery; based on the target open circuit voltage range and the first corresponding relationship, determine the target state of charge range of the battery.

[0163] In some embodiments, the calibration module can also be used to: when the current state of charge of the battery is greater than a first threshold, calibrate the state of charge of the battery to the first threshold; the first threshold includes the upper limit of the target state of charge range; when the current state of charge of the battery is less than a second threshold, calibrate the state of charge of the battery to the second threshold; the second threshold includes the lower limit of the target state of charge range.

[0164] In some embodiments, the calibration module may also be used to calibrate the current state of charge of the battery when the rate of change of the open circuit voltage of the battery with the state of charge exceeds a change rate threshold within the target state of charge range.

[0165] In some embodiments, the acquisition module may also be used to: collect first measurement terminal voltages corresponding to a plurality of moments in a target state of charge variation interval of the battery and first operating condition indicators corresponding to each of the first measurement terminal voltages; The second determination module can also be used to: average the first measurement terminal voltages collected at multiple times within the target charge state change interval to obtain an average measurement terminal voltage; average the multiple first model terminal voltages corresponding to the multiple first measurement terminal voltages to obtain an average model terminal voltage; and determine the difference between the average model terminal voltage and the average measurement terminal voltage as the first voltage error.

[0166] In some embodiments, the first operating condition indicator includes temperature and / or current ratio, and the above-mentioned state of charge calibration device may also include a third determination module, which is used for at least one of the following: when the first operating condition indicator includes temperature and the minimum temperature within the target state of charge change interval is not less than a minimum temperature threshold, determining that the first operating condition indicator meets the target operating condition; when the first operating condition indicator includes current ratio and the average current ratio within the target state of charge change interval is not greater than the average current ratio threshold, determining that the first operating condition indicator meets the target operating condition.

[0167] In some embodiments, the above-mentioned state of charge calibration device may also include a fourth determination module, which is used to: determine at least one candidate operating condition and a candidate voltage error range corresponding to each candidate operating condition; the candidate voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trustworthy condition; and determine the target operating condition corresponding to the reference voltage error range from the at least one candidate operating condition.

[0168] In some embodiments, the fourth determination module can also be used to: obtain at least one second measurement terminal voltage of the battery during the target test process, and the second operating condition indicator and measured state of charge corresponding to each second measurement terminal voltage; for each second measurement terminal voltage, based on the equivalent circuit model and the corresponding measured state of charge, determine the second model terminal voltage of the battery under the corresponding second operating condition indicator, and based on the second measurement terminal voltage, determine the second voltage error of the second model terminal voltage; based on the second operating condition indicator corresponding to each second measurement terminal voltage and the corresponding second voltage error, determine at least one of the candidate operating conditions and the candidate voltage error range having a corresponding relationship.

[0169] An embodiment of the present application provides a computer program, including a computer-readable code. When the computer-readable code is executed in a computer device, a processor in the computer device executes part or all of the steps in the above-mentioned state of charge calibration method.

[0170] An embodiment of the present application provides a computer program product, including a computer program or instructions, which, when executed by a processor, implements some or all of the steps in the above-mentioned state of charge calibration method.

[0171] An embodiment of the present application provides a computer-readable storage medium, which stores a computer program. The computer program can be executed by a processor to implement the above-mentioned state of charge calibration method.

[0172] The present application embodiment provides a battery system, such as Figure 4 As shown, the battery system 40 includes at least one battery 41 and a battery management system 42. The battery management system 42 is used to implement part or all of the steps in the above-mentioned state of charge calibration method.

[0173] The present application embodiment provides an electrical device, such as Figure 5 As shown, the electrical device 50 includes the battery system 40 in the above-mentioned application embodiment.

[0174] Here, electrical equipment may include but is not limited to automobiles, airplanes, electric bicycles, electric motorcycles, electric motorboats, ships, etc.

[0175] In the description of the present application, the description with reference to the terms "in one embodiment", "in some embodiments", "in other embodiments", "in yet other embodiments", or "exemplary" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the present application, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0176] The above is only an exemplary embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A method for calibrating a state of charge, characterized in that: The calibration method comprises: Acquire a first measurement terminal voltage of a battery and a first operating condition indicator corresponding to the first measurement terminal voltage; Determining a first model terminal voltage corresponding to the battery under the first operating condition indicator based on an equivalent circuit model of the battery and a current state of charge of the battery; determining a first voltage error of the first model terminal voltage based on the first measurement terminal voltage; When the first operating condition indicator meets the target operating condition and the first voltage error is not within the reference voltage error range corresponding to the target operating condition, the current state of charge of the battery is calibrated based on the first voltage error and the reference voltage error range; the reference voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trustworthy condition.

2. The method for calibrating the state of charge according to claim 1, characterized in that: The calibrating the current state of charge of the battery based on the first voltage error and the reference voltage error range includes: Based on the first voltage error and the reference voltage error range, a target voltage error range is determined; the upper limit of the target voltage error range is determined based on the difference between the first voltage error and the lower limit of the reference voltage error range, and the lower limit of the target voltage error range is determined based on the difference between the first voltage error and the upper limit of the reference voltage error range; Determining a target state of charge range of the battery based on the target voltage error range and the current state of charge of the battery; Based on the target state of charge range, the current state of charge of the battery is calibrated.

3. The method for calibrating the state of charge according to claim 2, characterized in that: The step of determining a target state of charge range of the battery based on the target voltage error range and the current state of charge of the battery includes: Based on the current state of charge of the battery, query a first corresponding relationship to obtain an estimated value of the current open circuit voltage of the battery; the first corresponding relationship represents a corresponding relationship between the open circuit voltage and the state of charge of the battery; Determining a target open circuit voltage range of the battery based on the estimated value and the target voltage error range; A target state of charge range of the battery is determined based on the target open circuit voltage range and the first corresponding relationship.

4. The method for calibrating the state of charge according to claim 2, characterized in that: The calibrating the current state of charge of the battery based on the target state of charge range includes: When the current state of charge of the battery is greater than a first threshold, calibrating the state of charge of the battery to the first threshold; the first threshold includes an upper limit of the target state of charge range; When the current state of charge of the battery is less than a second threshold, the state of charge of the battery is calibrated to the second threshold; the second threshold includes a lower limit of the target state of charge range.

5. The method for calibrating the state of charge according to claim 2, characterized in that: The calibrating the current state of charge of the battery based on the target state of charge range includes: When the rate of change of the open circuit voltage of the battery with the state of charge exceeds a rate of change threshold within the target state of charge range, the current state of charge of the battery is calibrated.

6. The method for calibrating the state of charge according to claim 1, characterized in that: The obtaining of a first measurement terminal voltage of the battery and a first operating condition indicator corresponding to the first measurement terminal voltage includes: Collecting first measurement terminal voltages of the battery corresponding to multiple moments within a target state of charge variation interval and first operating condition indicators corresponding to each of the first measurement terminal voltages; The determining, based on the first measurement terminal voltage, a first voltage error of the first model terminal voltage comprises: averaging the first measurement terminal voltages collected at multiple times within the target state of charge change interval to obtain an average measurement terminal voltage; averaging a plurality of the first model terminal voltages respectively corresponding to a plurality of the first measurement terminal voltages to obtain an average model terminal voltage; The difference between the average model terminal voltage and the average measurement terminal voltage is determined as the first voltage error.

7. The method for calibrating the state of charge according to claim 6, characterized in that: The first operating condition indicator includes temperature and / or current ratio, and the calibration method further includes at least one of the following: In a case where the first operating condition indicator includes temperature and a minimum temperature within the target state of charge variation interval is not less than a minimum temperature threshold, determining that the first operating condition indicator satisfies the target operating condition; When the first operating condition indicator includes a current multiplier and the average current multiplier within the target state of charge change interval is not greater than an average current multiplier threshold, it is determined that the first operating condition indicator meets the target operating condition.

8. The method for calibrating the state of charge according to any one of claims 1 to 7, characterized in that: The calibration method further comprises: Determine at least one candidate operating condition and a candidate voltage error range corresponding to each candidate operating condition; the candidate voltage error range represents an error range of a model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets a target trustworthy condition; The target operating condition corresponding to the reference voltage error range is determined from the at least one candidate operating condition.

9. The method for calibrating the state of charge according to claim 8, characterized in that: The determining of at least one candidate operating condition and a candidate voltage error range corresponding to each candidate operating condition includes: Acquire at least one second measurement terminal voltage of the battery during a target test, and a second operating condition indicator and a measured state of charge corresponding to each second measurement terminal voltage; For each second measurement terminal voltage, determine a second model terminal voltage of the battery under a corresponding second operating condition indicator based on the equivalent circuit model and the corresponding measured state of charge, and determine a second voltage error of the second model terminal voltage based on the second measurement terminal voltage; Based on the second operating condition indicators corresponding to each of the second measuring terminal voltages and the corresponding second voltage errors, at least one of the candidate operating condition and the candidate voltage error range having a corresponding relationship is determined.

10. A charge state calibration device, characterized in that: The calibration device comprises: An acquisition module, used to acquire a first measurement terminal voltage of the battery and a first operating condition indicator corresponding to the first measurement terminal voltage; A first determining module, configured to determine a first model terminal voltage corresponding to the battery under the first operating condition indicator based on an equivalent circuit model of the battery and a current state of charge of the battery; A second determining module, configured to determine a first voltage error of the first model terminal voltage based on the first measurement terminal voltage; A calibration module is used to calibrate the current state of charge of the battery based on the first voltage error and the reference voltage error range when the first operating condition indicator meets the target operating condition and the first voltage error is not within the reference voltage error range corresponding to the target operating condition; the reference voltage error range represents the error range of the model terminal voltage determined based on the equivalent circuit model when the state of charge of the battery meets the target trustworthy condition.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps in the method according to any one of claims 1 to 9 are implemented.

12. A computer program product comprising a computer program or instructions, characterized in that When the computer program or instruction is executed by a processor, the steps in the method according to any one of claims 1 to 9 are implemented.

13. A battery system, characterized in that: The invention comprises at least one battery and a battery management system; the battery management system is used to implement the steps in the method according to any one of claims 1 to 9.

14. An electrical device, characterized in that: Comprising the battery system as claimed in claim 13.

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