Battery state of charge calibration method, device and battery management system
Patent Information
- Application Number
- CN202610910862.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-23
- Publication Date
- 2026-10-30
AI Technical Summary
然而，在电网调频等典型的充放电频繁切换场景下，电池的极化状态复杂且静置时间有限，采用开路电压法校准需要依据电池的充放电状态从充电OCV曲线与放电OCV曲线中选取其一进行校准，而充放电频繁切换场景下该选取依据难以准确确定，进而影响SOC校准精度
[0015]本申请实施例的电池荷电状态校准方法，获取基于充电状态和放电状态下开路电压与荷电状态的映射关系而确定的目标映射关系，该目标映射关系综合了充电和放电两种工况下的开路电压特性，有助于在校准过程中避免因需要根据电池的历史充放电状态从充电曲线和放电曲线中选择其一而引入的误差，有利于提高荷电状态校准的准确性和可靠性。并且，在电池同时满足预设静置条件和预设校准条件时执行校准，能够在保证校准时机的合理性的同时，避免在电池状态不满足要求时执行无效校准，有助于提高荷电状态校准的准确性和有效性，同时也有利于减少不必要的校准操作，降低系统运算资源的消耗。
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Figure CN123019192A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of energy storage battery management technology, specifically to a battery state of charge calibration method, device, and battery management system. Background Technology
[0002] The Battery Management System (BMS) is an important component of energy storage systems. Its main functions include data acquisition, state estimation, charge and discharge control, and battery energy balancing. Among these, the State of Charge (SOC) is a key parameter characterizing the remaining usable capacity of a battery, and its accurate calibration is of great significance for the safe operation and lifespan management of the battery.
[0003] Battery SOC calibration can be achieved using the open-circuit voltage method, which utilizes the characteristic that the battery's terminal voltage approaches its open-circuit voltage (OCV) when at rest, and corrects the SOC by mapping the OCV to the SOC in the OCV curve. However, in typical scenarios with frequent charge-discharge switching, such as grid frequency regulation, the battery's polarization state is complex and the resting time is limited. Calibration using the open-circuit voltage method requires selecting either the charging OCV curve or the discharging OCV curve based on the battery's charge-discharge state. In scenarios with frequent charge-discharge switching, it is difficult to accurately determine this selection criterion, thus affecting the accuracy of SOC calibration. Summary of the Invention
[0004] A method, apparatus, and battery management system for calibrating the state of charge (SOC) of a battery are provided to improve the accuracy of SOC calibration.
[0005] Firstly, a method for calibrating the state of charge of a battery is provided, comprising the following steps: Obtain a target mapping relationship, wherein the target mapping relationship is determined based on a first mapping relationship and a second mapping relationship, the first mapping relationship being the mapping relationship between open circuit voltage and state of charge in the charging state, and the second mapping relationship being the mapping relationship between open circuit voltage and state of charge in the discharging state; When the battery meets the preset resting conditions and the preset calibration conditions, the current state of charge of the battery is calibrated according to the current terminal voltage of the battery and the target mapping relationship.
[0006] In some embodiments, the step of constructing the target mapping relationship includes: Within a preset state of charge range, the first state of charge corresponding to each candidate open circuit voltage is obtained from the first mapping relationship, and the second state of charge corresponding to each candidate open circuit voltage is obtained from the second mapping relationship. Based on the first and second states of charge corresponding to each candidate open-circuit voltage, determine the fitted state of charge corresponding to each candidate open-circuit voltage. The target mapping relationship is constructed based on each candidate open-circuit voltage and the fitted state of charge corresponding to each candidate open-circuit voltage.
[0007] In some embodiments, determining the fitted state of charge corresponding to each candidate open-circuit voltage based on the first state of charge and the second state of charge corresponding to each candidate open-circuit voltage includes: The arithmetic mean of the first state of charge and the second state of charge corresponding to each candidate open-circuit voltage is determined as the fitted state of charge corresponding to each candidate open-circuit voltage.
[0008] In some embodiments, constructing the target mapping relationship based on each candidate open-circuit voltage and the fitted state of charge corresponding to each candidate open-circuit voltage includes: For each candidate open-circuit voltage and the corresponding fitted state of charge, a fitting mapping relationship is obtained; Integer states of charge are extracted from the fitted mapping relationship, and the integer states of charge and the corresponding candidate open-circuit voltages are determined as the target mapping relationship.
[0009] In some embodiments, the battery is a lithium iron phosphate battery, and the preset state of charge range is any range from 0% to 30% state of charge.
[0010] In some embodiments, determining that the battery meets preset resting conditions includes: Obtain the current current and resting time of the battery during the current resting phase; If the absolute value of the current is less than a preset current threshold and the resting time reaches a preset time threshold, the battery is determined to meet the preset resting conditions.
[0011] In some embodiments, determining that the battery meets preset calibration conditions includes: Determine the reference open-circuit voltage corresponding to the reference state of charge in the target mapping relationship; When the current terminal voltage is less than the reference open-circuit voltage, the target state of charge corresponding to the current terminal voltage is determined according to the target mapping relationship; If the deviation between the current state of charge and the target state of charge is greater than a preset error threshold, the battery is determined to meet the preset calibration conditions.
[0012] In some embodiments, calibrating the current state of charge of the battery based on the current terminal voltage of the battery and the target mapping relationship includes: Update the current state of charge to the target state of charge.
[0013] Secondly, a battery state of charge calibration device is also provided, comprising: An acquisition module is used to acquire a target mapping relationship, wherein the target mapping relationship is determined based on a first mapping relationship and a second mapping relationship, the first mapping relationship being the mapping relationship between open circuit voltage and state of charge in the charging state, and the second mapping relationship being the mapping relationship between open circuit voltage and state of charge in the discharging state; The calibration module is used to calibrate the current state of charge of the battery according to the current terminal voltage of the battery and the target mapping relationship, provided that the battery meets the preset resting conditions and the preset calibration conditions.
[0014] Thirdly, a battery management system is also provided, including: Storage device for storing target mapping relationships; The battery state of charge calibration device as described in the second aspect is connected to the storage device.
[0015] The battery state-of-charge (SOC) calibration method of this application obtains a target mapping relationship based on the mapping relationship between open-circuit voltage and SOC under charging and discharging states. This target mapping relationship integrates the open-circuit voltage characteristics under both charging and discharging conditions, helping to avoid errors introduced during calibration by selecting either the charging curve or the discharging curve based on the battery's historical charging and discharging states. This improves the accuracy and reliability of SOC calibration. Furthermore, calibration is performed when the battery simultaneously meets preset resting conditions and preset calibration conditions. This ensures the rationality of the calibration timing while avoiding invalid calibration when the battery state does not meet the requirements, thus improving the accuracy and effectiveness of SOC calibration. It also helps to reduce unnecessary calibration operations and lower the consumption of system computing resources. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the overall process of the battery state of charge calibration method according to an embodiment of this application; Figure 2 This is a schematic diagram illustrating the target mapping relationship in an embodiment of this application; Figure 3 This is a schematic diagram of the battery state of charge calibration device according to an embodiment of this application; Figure 4 This is a schematic diagram of the battery management system according to an embodiment of this application.
[0018] Explanation of reference numerals in the attached figures: 10-Battery management system; 11-Battery state of charge calibration device; 111-Acquisition module; 112-Calibration module; 12-Storage device; 20-Battery. Detailed Implementation
[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0020] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.
[0021] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.
[0022] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values may in practice be based on additional conditions or values beyond those stated.
[0023] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.
[0024] Energy storage technology, as an important means of energy supply, can improve the quality, stability, and reliability of power grid supply. Due to the characteristics of lithium batteries, such as high power density, long cycle life, and no memory effect, lithium battery energy storage technology has become the mainstream technology in energy storage and is being applied in more and more scenarios.
[0025] With the gradual achievement of carbon reduction and energy conservation goals, new energy vehicles and electrochemical energy storage technologies have experienced rapid development and widespread application. Energy storage technology, as a crucial means of energy supply, can improve the quality, stability, and reliability of power grid supply. Due to the high power density, long cycle life, and lack of memory effect of lithium batteries, lithium battery energy storage technology has become the mainstream technology in energy storage and is being applied in an increasing number of scenarios.
[0026] The Battery Management System (BMS) is a crucial component of energy storage systems. Its main functions include data acquisition, state estimation, charge / discharge control, and battery energy balancing. Among these, the State of Charge (SOC) is closely related to lithium battery safety, cycle life, and cost, thus requiring accurate SOC estimation. Battery SOC calibration can be achieved using the open-circuit voltage method, which leverages the characteristic that the battery's terminal voltage approaches its Open Circuit Voltage (OCV) when at rest, correcting the SOC through the mapping relationship between OCV and SOC in the OCV curve. However, in typical scenarios with frequent charge / discharge switching, such as grid frequency regulation, the battery's polarization state is complex, and the resting time is limited. Calibration using the open-circuit voltage method requires selecting either the charging OCV curve or the discharging OCV curve based on the battery's charge / discharge state. In scenarios with frequent charge / discharge switching, accurately determining this selection criterion is difficult, and incorrect curve selection often leads to significant errors, affecting the accuracy of SOC calibration.
[0027] In view of this, this application provides a battery state of charge (SOC) calibration method. By obtaining a target mapping relationship jointly determined by the mapping relationship between open circuit voltage and SOC under charging and discharging conditions, the current SOC of the battery is calibrated according to the current terminal voltage and the target mapping relationship when the battery meets preset resting conditions and preset calibration conditions. This eliminates the need to select a single curve from the charging and discharging curves for calibration, which helps to improve the accuracy and reliability of SOC calibration in scenarios with frequent charge and discharge switching.
[0028] Please see Figure 1 , Figure 1 This is a schematic flowchart of the battery state-of-charge calibration method according to an embodiment of this application. The method is applied to a battery management system and specifically includes the following steps S101 to S102: Step S101: Obtain the target mapping relationship, wherein the target mapping relationship is determined based on the first mapping relationship and the second mapping relationship. The first mapping relationship is the mapping relationship between the open circuit voltage and the state of charge in the charging state, and the second mapping relationship is the mapping relationship between the open circuit voltage and the state of charge in the discharging state.
[0029] For example, the battery in this application embodiment may be a lithium iron phosphate battery or other types of lithium batteries with hysteresis effect.
[0030] In some examples, the target mapping relationship is a pre-built mapping relationship stored in the battery management system's storage unit. When the battery is in the charging / discharging operating state and in the resting state after charging / discharging, the battery management system collects the operating parameters of each battery in real time through built-in voltage, current, and temperature sensors, including but not limited to terminal voltage, operating current, and temperature. Simultaneously, the battery management system is equipped with a storage unit that continuously records and updates the battery's state parameters, including real-time estimated state of charge, cumulative charge ampere-hours, cumulative discharge ampere-hours, cumulative charge watt-hours, and cumulative discharge watt-hours, providing a data foundation for subsequent state assessment and calibration.
[0031] In some embodiments, the steps for constructing the first mapping relationship and the second mapping relationship include: Under multiple preset ambient temperatures, the test batteries were subjected to complete constant current charging followed by rest and constant current discharging followed by rest. Record the open-circuit voltage and corresponding SOC point of the battery after it has been allowed to stand for a sufficient period of time (e.g., 2 hours or more) to reach electrochemical equilibrium, thereby obtaining the charging OCV-SOC curve and the discharging OCV-SOC curve at different preset ambient temperatures. Using linear interpolation, charging OCV-SOC curves and discharging OCV-SOC curves at any ambient temperature are constructed. The charging OCV-SOC curve at the current temperature is determined as the first mapping relationship, and the discharging OCV-SOC curve at the current temperature is determined as the second mapping relationship.
[0032] Specifically, the first mapping relationship is constructed based on the open-circuit voltage and corresponding SOC point during the resting period after a complete constant-current charge of the test battery. The second mapping relationship is constructed based on the open-circuit voltage and corresponding SOC point during the resting period after a complete constant-current discharge of the test battery.
[0033] For example, the plurality of preset ambient temperatures include at least a portion of -10°C, 0°C, 25°C, and 45°C.
[0034] Please see Figure 2 , Figure 2 This is a schematic diagram illustrating the target mapping relationship in an embodiment of this application. In some embodiments, the step of constructing the target mapping relationship includes: Within a preset state of charge range, the first state of charge corresponding to each candidate open circuit voltage is obtained from the first mapping relationship, and the second state of charge corresponding to each candidate open circuit voltage is obtained from the second mapping relationship. Based on the first and second states of charge corresponding to each candidate open-circuit voltage, determine the fitted state of charge corresponding to each candidate open-circuit voltage. A target mapping relationship is constructed based on each candidate open-circuit voltage and the fitted state of charge corresponding to each candidate open-circuit voltage.
[0035] For example, the preset state of charge (SOC) range is a region where the OCV-SOC curve changes relatively significantly and is sensitive to calibration. When the battery is a lithium iron phosphate battery, the preset SOC range is any interval within the range of 0% to 30% SOC. For example, the preset SOC range can be 0% to 30%, or any interval within the range of 0% to 30%. In other examples, the upper limit of the preset SOC range can exceed 30%. Specifically, it can be selected based on the specific changes in the OCV-SOC curve, choosing a region with low SOC and significant changes, such as the non-voltage plateau region of the OCV-SOC curve.
[0036] Specifically, after obtaining the first mapping relationship SOC-OCV chg The second mapping relationship SOC-OCV dis Then, the first mapping relationship SOC-OCV chg The preset state of charge range corresponds to an open-circuit voltage range, and the second mapping relationship is SOC-OCV. disThe preset state of charge (SOC) range corresponds to another open-circuit voltage range. Candidate open-circuit voltages can be determined from the overlapping range of these two open-circuit voltage ranges. Based on the first state of charge (SOC) corresponding to each candidate open-circuit voltage... chg Second State of Charge (SOC) dis The fitted state of charge (SOC) is determined for each candidate open-circuit voltage. By fitting the SOC to the corresponding fitted SOC of a series of candidate open-circuit voltages, the target mapping relationship SOC-OCV can be obtained. T Target mapping relationship SOC-OCV T It can be a mapping relationship between each SOC and open-circuit voltage within a preset state of charge range. In this way, the target mapping relationship takes into account the open-circuit voltage characteristics under both charging and discharging conditions, thus eliminating the need to determine the battery's historical charge and discharge states to select the charging or discharging curve during the calibration process.
[0037] In some embodiments, determining the fitted state of charge corresponding to each candidate open-circuit voltage based on the first state of charge and the second state of charge corresponding to each candidate open-circuit voltage can be achieved in the following manner: The first state of charge (SOC) corresponding to each candidate open-circuit voltage. chg Second State of Charge (SOC) dis The arithmetic mean of the values is used to determine the fitted state of charge (SOC) for each candidate open-circuit voltage. T .
[0038] Specifically, fitting the state of charge (SOC) T This is equivalent to the pseudo-SOC corresponding to each alternative open-circuit voltage. SOC T =(SOC chg +SOC dis ) / 2.
[0039] In some embodiments, the target mapping relationship is constructed based on each candidate open-circuit voltage and the fitted state of charge corresponding to each candidate open-circuit voltage, which can be achieved in the following ways: For each candidate open-circuit voltage and the corresponding fitted state of charge, a fitting mapping relationship is obtained; Integer states of charge are extracted from the fitted mapping relationship, and the integer states of charge and their corresponding candidate open-circuit voltages are determined as the target mapping relationship.
[0040] Specifically, the entire preset state of charge (SOC) range is traversed, and a series of candidate open-circuit voltages and their corresponding fitted SOCs are fitted to obtain a fitted mapping relationship, i.e., a pseudo-OCV-SOC curve. Finally, integer SOCs (e.g., 0%, 1%, 2%, ... 30%) on the curve and their corresponding OCV values are extracted to generate a pseudo-OCV-SOC preset calibration table. This pseudo-OCV-SOC preset calibration table is then used as the target mapping relationship and pre-stored in the battery management system's storage unit.
[0041] In other examples, the fitted mapping relationship can also be used as the target mapping relationship, and there is no specific limitation on this.
[0042] Step S102: When the battery meets the preset resting conditions and the preset calibration conditions, calibrate the current state of charge of the battery according to the current terminal voltage of the battery and the target mapping relationship.
[0043] Specifically, in the resting state, the current terminal voltage can be approximated as the actual SOC. The current state of charge is estimated by the battery management system using the ampere-hour integration method. Preset resting conditions are used to confirm that the battery has stopped charging and discharging and entered a resting state suitable for calibration. Preset calibration conditions are used to further determine whether the current moment meets the trigger conditions for performing state of charge calibration, based on the battery already meeting the resting conditions. This dual-condition judgment helps improve the accuracy and reliability of state of charge calibration.
[0044] In some embodiments, determining that the battery meets preset resting conditions can be achieved in the following ways: Obtain the current current and resting time of the battery during the current resting phase; If the absolute value of the current is less than the preset current threshold and the resting time reaches the preset time threshold, the battery is determined to meet the preset resting conditions.
[0045] Specifically, the current is collected in real time by a current sensor, and the resting time is accumulated from the moment the battery enters the resting state. A preset current threshold is used to determine whether the battery has entered the resting state; this threshold is set to a current value close to zero. When the absolute value of the battery's current is less than the preset current threshold, it indicates that the battery has essentially stopped charging and discharging. A preset time threshold is used to ensure that the battery's polarization voltage is fully relaxed; this threshold can be set according to the battery's characteristics and application scenario. When the absolute value of the current is less than the preset current threshold and the resting time reaches the preset time threshold, the battery management system determines that the battery meets the preset resting conditions, at which point the battery has the basic conditions to perform open-circuit voltage calibration.
[0046] In some examples, the preset current threshold is 0.05C and the preset time threshold is 30 minutes. When the absolute value of the battery's current is less than 0.05C and the resting time reaches 30 minutes, the battery management system determines that the battery meets the preset resting conditions.
[0047] In some embodiments, determining that the battery meets preset calibration conditions includes: Determine the reference open-circuit voltage corresponding to the reference state of charge in the target mapping relationship; When the current terminal voltage is less than the reference open-circuit voltage, the target state of charge corresponding to the current terminal voltage is determined according to the target mapping relationship; If the deviation between the current state of charge and the target state of charge is greater than a preset error threshold, the battery is determined to meet the preset calibration conditions.
[0048] Specifically, after the battery management system (BMS) determines that the battery meets the preset resting conditions, it acquires the current terminal voltage of the battery during the current resting phase and compares it with the reference open-circuit voltage according to the target mapping relationship to determine whether the battery's current state of charge (SOC) range is suitable for calibration. The BMS first determines the reference open-circuit voltage corresponding to the reference SOC in the target mapping relationship. The reference SOC is a preset SOC value in the target mapping relationship, and the corresponding open-circuit voltage serves as the threshold for determining whether the battery has entered a low SOC range. The BMS compares the battery's current terminal voltage with the reference open-circuit voltage. If the current terminal voltage is less than the reference open-circuit voltage, it indicates that the battery's current SOC is below the reference SOC and falls within a range where the open-circuit voltage changes significantly with the SOC, making calibration suitable. If the current terminal voltage is greater than or equal to the reference open-circuit voltage, it indicates that the battery's current SOC is above the reference SOC and is not suitable for calibration; the BMS continues to monitor the battery's resting state.
[0049] When the current terminal voltage is lower than the reference open-circuit voltage, the battery management system (BMS) queries the target mapping relationship based on the current terminal voltage, determining the target state of charge (SOC) corresponding to the current terminal voltage from the target mapping relationship through table lookup or interpolation. After obtaining the target SOC, the BMS acquires the real-time estimated current SOC and calculates the deviation between the current SOC and the target SOC, specifically represented by the absolute value of the deviation. If the deviation is greater than a preset error threshold, it indicates a significant error between the current SOC estimated by the BMS and the actual SOC, requiring calibration. If the deviation is less than or equal to the preset error threshold, it indicates that the accuracy of the current SOC estimation is within an acceptable range. The BMS determines that the battery does not meet the preset calibration conditions, does not perform calibration updates, and maintains the current SOC.
[0050] For example, the reference state of charge (SOC) is 30%, which is the open-circuit voltage corresponding to a SOC of 30% in the target mapping relationship. The preset error threshold is 2%. When the absolute value of the deviation between the current SOC and the target SOC is greater than 2%, the battery management system determines that the battery meets the preset calibration conditions and performs calibration; when the absolute value of the deviation is less than or equal to 2%, calibration is not performed.
[0051] The above approach helps reduce unnecessary calibration updates when the error is small, thus reducing the consumption of system computing resources.
[0052] In some embodiments, when it is determined that the battery meets preset resting conditions and preset calibration conditions, the current state of charge of the battery is calibrated according to the current terminal voltage of the battery and the target mapping relationship. Specifically, this can be achieved in the following ways: Update the current state of charge to the target state of charge.
[0053] Specifically, if the battery meets the preset resting conditions and preset calibration conditions, the current state of charge (SOC) is updated to the target SOC. If the battery does not meet the preset resting conditions or preset calibration conditions, no update is needed, and the battery management system maintains the current SOC.
[0054] Through the above scheme, this embodiment of the application utilizes a pre-fitted target mapping relationship between the charge and discharge curves as a unified calibration benchmark during battery resting periods. This avoids the dilemma of choosing between the charging OCV curve and the discharging OCV curve for calibration after frequent charge-discharge switching. This method can trigger calibration after a shorter resting time, shortening the open-circuit voltage calibration resting time and effectively reducing errors caused by incorrect curve selection. This improves the long-term accuracy and reliability of SOC estimation, enabling more effective monitoring and precise management of the energy storage battery's state.
[0055] On the other hand, embodiments of this application provide a battery state of charge calibration device.
[0056] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a battery state of charge calibration device according to an embodiment of this application. The battery state of charge calibration device 11 includes an acquisition module 111 and a calibration module 112.
[0057] The acquisition module 111 is used to acquire the target mapping relationship, wherein the target mapping relationship is determined based on the first mapping relationship and the second mapping relationship. The first mapping relationship is the mapping relationship between the open circuit voltage and the state of charge in the charging state, and the second mapping relationship is the mapping relationship between the open circuit voltage and the state of charge in the discharging state. The calibration module 112 is used to calibrate the current state of charge of the battery according to the current terminal voltage and target mapping relationship, provided that the battery meets the preset resting conditions and the preset calibration conditions.
[0058] In some embodiments, the apparatus further includes a construction module for constructing a target mapping relationship through the following steps: Within a preset state of charge range, the first state of charge corresponding to each candidate open circuit voltage is obtained from the first mapping relationship, and the second state of charge corresponding to each candidate open circuit voltage is obtained from the second mapping relationship. Based on the first and second states of charge corresponding to each candidate open-circuit voltage, determine the fitted state of charge corresponding to each candidate open-circuit voltage. A target mapping relationship is constructed based on each candidate open-circuit voltage and the fitted state of charge corresponding to each candidate open-circuit voltage.
[0059] In some embodiments, the construction module is specifically used for: The arithmetic mean of the first and second states of charge corresponding to each candidate open-circuit voltage is used to determine the fitted state of charge corresponding to each candidate open-circuit voltage.
[0060] In some embodiments, the construction module is specifically used for: For each candidate open-circuit voltage and the corresponding fitted state of charge, a fitting mapping relationship is obtained; Integer states of charge are extracted from the fitted mapping relationship, and the integer states of charge and their corresponding candidate open-circuit voltages are determined as the target mapping relationship.
[0061] In some embodiments, the battery is a lithium iron phosphate battery, and the preset state of charge range is any range from 0% to 30% state of charge.
[0062] In some embodiments, the calibration module 112 is specifically used for: Obtain the current current and resting time of the battery during the current resting phase; If the absolute value of the current is less than the preset current threshold and the resting time reaches the preset time threshold, the battery is determined to meet the preset resting conditions.
[0063] In some embodiments, the calibration module 112 is specifically used for: Determine the reference open-circuit voltage corresponding to the reference state of charge in the target mapping relationship; When the current terminal voltage is less than the reference open-circuit voltage, the target state of charge corresponding to the current terminal voltage is determined according to the target mapping relationship; If the deviation between the current state of charge and the target state of charge is greater than a preset error threshold, the battery is determined to meet the preset calibration conditions.
[0064] In some embodiments, the calibration module 112 is specifically used for: Update the current state of charge to the target state of charge.
[0065] The battery state-of-charge (SOC) calibration device of this application obtains a target mapping relationship based on the mapping relationship between open-circuit voltage and SOC under charging and discharging states. This target mapping relationship integrates the open-circuit voltage characteristics under both charging and discharging conditions, helping to avoid errors introduced during calibration by selecting either the charging curve or the discharging curve based on the battery's historical charging and discharging states. This improves the accuracy and reliability of SOC calibration. Furthermore, calibration is performed when the battery simultaneously meets preset resting conditions and preset calibration conditions. This ensures the rationality of the calibration timing while avoiding invalid calibration when the battery state does not meet the requirements, thus improving the accuracy and effectiveness of SOC calibration. It also helps reduce unnecessary calibration operations and lowers the consumption of system computing resources.
[0066] On the other hand, embodiments of this application provide a battery management system.
[0067] Please see Figure 4 , Figure 4 This is a schematic diagram of the battery management system according to an embodiment of this application. The battery management system 10 is connected to the battery 20 and includes a storage device 12 and a battery state-of-charge calibration device 11. The storage device 12 is used to store target mapping relationships, and the battery state-of-charge calibration device 11 is connected to the storage device 12 and is used to execute the battery state-of-charge calibration method according to the embodiment of this application.
[0068] The battery management system 10 of this application embodiment obtains a target mapping relationship determined based on the mapping relationship between open-circuit voltage and state of charge (SOC) under charging and discharging states. This target mapping relationship integrates the open-circuit voltage characteristics under both charging and discharging conditions, which helps to avoid errors introduced during calibration due to the need to select either the charging curve or the discharging curve based on the battery's historical charging and discharging states. This improves the accuracy and reliability of SOC calibration. Furthermore, calibration is performed when the battery simultaneously meets preset resting conditions and preset calibration conditions. This ensures the rationality of the calibration timing while avoiding invalid calibration when the battery state does not meet the requirements, thus improving the accuracy and effectiveness of SOC calibration. It also helps to reduce unnecessary calibration operations and lower the consumption of system computing resources.
[0069] This embodiment also provides a computer-readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to perform the steps of any of the methods in the above embodiments.
[0070] In the embodiments of this application, the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.
[0071] It should be noted that, in the data processing stage, the technical solution of this application has strictly limited the scope of data collection to the minimum necessary to achieve the technical objectives, preventing the acquisition of irrelevant information. For any user information to be collected, the data subject will be clearly informed and their consent obtained. Furthermore, technologies such as encrypted storage and access control are employed to strengthen data security and ensure the security and compliance of the entire data processing process. The technical model and decision-making mechanism are based on objective technical parameters and do not introduce unnecessary parameters such as gender or age that may lead to discrimination, resolutely eliminating algorithmic discrimination and upholding public order and good morals. In addition, the specification fully describes the technical implementation methods, application scenarios, and compliance protection details. The claims are consistent with the content of the specification, key compliance designs are clear and verifiable, and the overall technical design is guided by the protection of public interests and adherence to social ethics, without any circumstances that harm public interests or violate public order and good morals.
[0072] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.
[0073] The foregoing has provided a detailed description of a battery state-of-charge calibration method, apparatus, and battery management system provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A method for calibrating the state of charge of a battery, characterized in that, Includes the following steps: Obtain a target mapping relationship, wherein the target mapping relationship is determined based on a first mapping relationship and a second mapping relationship, the first mapping relationship being the mapping relationship between open circuit voltage and state of charge in the charging state, and the second mapping relationship being the mapping relationship between open circuit voltage and state of charge in the discharging state; When the battery meets the preset resting conditions and the preset calibration conditions, the current state of charge of the battery is calibrated according to the current terminal voltage of the battery and the target mapping relationship.
2. The battery state-of-charge calibration method according to claim 1, characterized in that, The steps for constructing the target mapping relationship include: Within a preset state of charge range, the first state of charge corresponding to each candidate open circuit voltage is obtained from the first mapping relationship, and the second state of charge corresponding to each candidate open circuit voltage is obtained from the second mapping relationship. Based on the first and second states of charge corresponding to each candidate open-circuit voltage, determine the fitted state of charge corresponding to each candidate open-circuit voltage. The target mapping relationship is constructed based on each candidate open-circuit voltage and the fitted state of charge corresponding to each candidate open-circuit voltage.
3. The battery state-of-charge calibration method according to claim 2, characterized in that, The step of determining the fitted state of charge corresponding to each candidate open-circuit voltage based on the first state of charge and the second state of charge corresponding to each candidate open-circuit voltage includes: The arithmetic mean of the first state of charge and the second state of charge corresponding to each candidate open-circuit voltage is determined as the fitted state of charge corresponding to each candidate open-circuit voltage.
4. The battery state-of-charge calibration method according to claim 2, characterized in that, The step of constructing the target mapping relationship based on each candidate open-circuit voltage and the fitted state of charge corresponding to each candidate open-circuit voltage includes: For each candidate open-circuit voltage and the corresponding fitted state of charge, a fitting mapping relationship is obtained; Integer states of charge are extracted from the fitted mapping relationship, and the integer states of charge and the corresponding candidate open-circuit voltages are determined as the target mapping relationship.
5. The battery state-of-charge calibration method according to claim 2, characterized in that, The battery is a lithium iron phosphate battery, and the preset state of charge range is any range from 0% to 30% state of charge.
6. The battery state-of-charge calibration method according to claim 1, characterized in that, Determining that the battery meets preset resting conditions includes: Obtain the current current and resting time of the battery during the current resting phase; If the absolute value of the current is less than a preset current threshold and the resting time reaches a preset time threshold, the battery is determined to meet the preset resting conditions.
7. The battery state-of-charge calibration method according to claim 1, characterized in that, Determining that the battery meets preset calibration conditions includes: Determine the reference open-circuit voltage corresponding to the reference state of charge in the target mapping relationship; When the current terminal voltage is less than the reference open-circuit voltage, the target state of charge corresponding to the current terminal voltage is determined according to the target mapping relationship; If the deviation between the current state of charge and the target state of charge is greater than a preset error threshold, the battery is determined to meet the preset calibration conditions.
8. The battery state-of-charge calibration method according to claim 7, characterized in that, Based on the current terminal voltage of the battery and the target mapping relationship, calibrate the current state of charge of the battery, including: Update the current state of charge to the target state of charge.
9. A battery state of charge calibration device, characterized in that, include: An acquisition module is used to acquire a target mapping relationship, wherein the target mapping relationship is determined based on a first mapping relationship and a second mapping relationship, the first mapping relationship being the mapping relationship between open circuit voltage and state of charge in the charging state, and the second mapping relationship being the mapping relationship between open circuit voltage and state of charge in the discharging state; The calibration module is used to calibrate the current state of charge of the battery according to the current terminal voltage of the battery and the target mapping relationship, provided that the battery meets the preset resting conditions and the preset calibration conditions.
10. A battery management system, characterized in that, include: Storage device for storing target mapping relationships; The battery state of charge calibration device as described in claim 9 is connected to the storage device.