Methods, systems, equipment, and dielectrics for estimating the state of charge of lithium batteries without current sampling

Abstract

This invention relates to the field of battery management technology, and provides a method, system, device, and medium for estimating the state of charge (SOC) of a lithium battery without current sampling. The method includes determining the current estimated boundary state range based on the current operating data of the target battery pack, the remaining capacity at the previous time, and a preset open-circuit voltage-remaining capacity mapping relationship; performing SOC analysis based on the cell voltage and the current estimated boundary state range to obtain the current SOC; and performing SOC display correction based on the current battery state obtained from battery state analysis using current remaining capacity and historical cell voltage time-series data, the current SOC, and preset SOC monotonicity constraints to obtain the target battery's SOC. This invention enables SOC estimation that conforms to actual capacity changes and suppresses reverse drift under low-cost battery management conditions without current sampling, effectively meeting the dynamic tracking requirements of accurate, stable, reliable, and user-friendly SOC tracking.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a method, system, device and medium for estimating the state of charge of a lithium battery without current sampling. Background Technology

[0002] The State of Charge (SOC) of a lithium battery is one of the key parameters in the Battery Management System (BMS). It provides a basis for energy management, range prediction, and safety control, and is also one of the most important indicators that are of utmost concern during the use of lithium batteries, playing an indispensable role.

[0003] Current mainstream SOC estimation methods can be broadly categorized into two types: ampere-hour integration methods and model-based estimation methods. Ampere-hour integration methods calculate SOC changes by integrating the current signal. While simple to implement and with good real-time performance, they heavily rely on current sampling accuracy and zero-drift stability, making them difficult to apply directly to low-cost systems or systems without current sensing hardware. Meanwhile, model-based estimation methods (such as extended Kalman filtering and sliding mode observers) typically rely on the battery's electrochemical model or equivalent circuit model, combining current, voltage, and temperature signals for state estimation. Although they perform well in terms of accuracy and dynamic response, they require precise current sampling and complex parameter identification, and involve significant computational load, making them unsuitable for low-cost platforms with limited hardware resources. While some research has proposed static estimation based on the characteristic relationship between open circuit voltage (OCV) and SOC to address cost, hardware resource constraints, and current dependence, under dynamic charge and discharge conditions, voltage response exhibits hysteresis and polarization effects, easily leading to reverse drift phenomena where SOC increases during discharge and decreases during charging. This is inconsistent with user experience and fails to accurately reflect the true trend of SOC changes. Therefore, existing technologies cannot achieve accurate, stable, and user-friendly dynamic SOC estimation under current-free sampling conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a current-sampling-free method for estimating the state of charge (SOC) of lithium batteries, which at least partially solves the technical problems of existing SOC estimation techniques that heavily rely on current sampling, have high hardware resource costs, and are prone to SOC reverse drift.

[0005] To achieve the above objectives, it is necessary to provide a method, system, computer equipment, and storage medium for estimating the state of charge of lithium batteries without current sampling.

[0006] In a first aspect, embodiments of the present invention provide a method for estimating the state of charge of a lithium battery without current sampling, the method comprising: Obtain the current operating data and the remaining capacity of the target battery pack at the previous moment. The current operating data includes cell voltage and battery temperature. Based on the cell voltage, the battery temperature, the remaining capacity at the previous moment, and the preset open-circuit voltage-remaining capacity mapping relationship, the current estimated boundary state range is determined, and the current estimated boundary state range includes the current estimated voltage range and the current estimated remaining capacity range. Linear interpolation is performed based on the cell voltage and the current estimated boundary state range to obtain the current remaining battery capacity, and state of charge analysis is performed based on the current remaining battery capacity to obtain the current state of charge. The current battery status is obtained by analyzing the current remaining battery capacity and historical cell voltage time-series data. The target battery state of charge is obtained by correcting the state of charge display based on the current battery state, the current state of charge, and the preset monotonicity constraint of the state of charge.

[0007] Furthermore, the step of obtaining the remaining capacity at the previous moment includes: Read the charge state from the previous moment from the preset storage medium; When the previous state of charge is successfully read, the available remaining capacity is analyzed based on the previous state of charge, the battery maximum capacity, the top reserved capacity, and the bottom reserved capacity to obtain the remaining capacity at the previous moment. When the state of charge reading of the previous moment fails, the first stable cell voltage is obtained, and the remaining capacity of the previous moment is obtained according to the mapping relationship between the first stable cell voltage and the preset open circuit voltage remaining capacity.

[0008] Furthermore, the current estimated voltage range includes an estimated voltage start point and an estimated voltage end point; the current estimated remaining capacity range includes an estimated remaining capacity start point and an estimated remaining capacity end point; The step of determining the current estimated boundary state range based on the cell voltage, the battery temperature, the remaining capacity at the previous moment, and the preset open-circuit voltage-remaining capacity mapping relationship includes: When it is determined that the estimated boundary state range needs to be updated based on the cell voltage and the estimated voltage range at the previous moment, the cell voltage and the remaining capacity at the previous moment are updated to the corresponding estimated voltage start point and estimated remaining capacity start point, respectively. Based on the estimated remaining capacity starting point and the preset open-circuit voltage remaining capacity mapping relationship, the corresponding estimated open-circuit voltage starting point is obtained; Based on the relationship between the cell voltage and the estimated open-circuit voltage start point, the current charging / discharging direction is obtained; Based on the current charging / discharging direction, the battery temperature, the estimated remaining capacity starting point, and the preset correction ratio, the endpoint boundary state is iteratively estimated, and the estimated voltage endpoint and the estimated remaining capacity endpoint are updated. The current estimated voltage range is obtained based on the updated estimated voltage start point and the estimated voltage end point, and the current estimated remaining capacity range is obtained based on the updated estimated remaining capacity start point and the estimated remaining capacity end point.

[0009] Further, the step of iteratively estimating the endpoint boundary state based on the current charging / discharging direction, the battery temperature, the estimated remaining capacity starting point, and the preset correction ratio, and updating the estimated voltage endpoint and the estimated remaining capacity endpoint, includes: The estimated remaining capacity starting point is set as the iteration initial value of the estimated remaining capacity ending point, and the capacity correction step size is determined according to the preset correction ratio and the maximum battery capacity. Based on the initial iteration value and the capacity correction step size, perform a step update corresponding to the current charging and discharging direction on the estimated remaining capacity endpoint to obtain the corresponding iterative estimated remaining capacity endpoint. Based on the remaining capacity endpoint of the iterative estimation and the battery temperature, the voltage endpoint is estimated to obtain the corresponding iterative estimated voltage endpoint, and it is determined whether the preset iterative estimation termination condition is met based on the iterative estimated voltage endpoint. When the conditions are met, the estimated remaining capacity endpoint and the estimated voltage endpoint are obtained according to the preset termination boundary determination rule of the iterative estimation of the remaining capacity endpoint and the iterative estimation of the voltage endpoint. If the condition is not met, update the initial value of the iteration based on the endpoint of the remaining capacity estimation in the iteration and continue the iteration estimation.

[0010] Further, the step of estimating the voltage endpoint based on the iteratively estimated remaining capacity endpoint and the battery temperature to obtain the corresponding iteratively estimated voltage endpoint includes: Based on the iterative estimation of the remaining capacity endpoint and the preset open-circuit voltage-remaining capacity mapping relationship, the corresponding iterative static open-circuit voltage is obtained; Based on the battery temperature, the endpoint of the iterative estimation of remaining capacity, the current charging / discharging direction, and the preset voltage change mapping table, the iterative static open-circuit voltage change is obtained; The iteratively set open-circuit voltage is corrected based on the change in the iteratively set open-circuit voltage to obtain the corresponding iteratively estimated voltage endpoint.

[0011] Furthermore, the step of performing battery state analysis based on the current remaining battery capacity and historical cell voltage time-series data to obtain the current battery state includes: Based on the current remaining battery capacity, the corresponding static open-circuit voltage is obtained, and the cell voltage is analyzed based on the static open-circuit voltage to obtain the corresponding instantaneous battery state. According to the preset state change mechanism, the voltage change characteristics of the historical cell voltage time series data are analyzed to obtain the long-term state of the battery; the preset state change mechanism includes judging the voltage stability state and the battery charge and discharge state based on the voltage change amplitude extracted by the sliding time window. The current battery state is obtained by performing a comprehensive state analysis based on the instantaneous state and the long-term state of the battery.

[0012] Furthermore, the preset state of charge monotonicity constraint includes a monotonically increasing state of charge during charging, a monotonically decreasing state of charge during discharging, and a unchanged state of charge during rest. The step of correcting the state of charge display based on the current battery state, the current state of charge, and a preset monotonicity constraint of the state of charge to obtain the target battery state of charge includes: The magnitude of the change in charge state is obtained based on the difference between the current charge state and the charge state at the previous moment. The updated state of charge value is obtained based on the current battery state, the magnitude of the state of charge change, and the preset state of charge monotonicity constraint. The target battery state of charge is obtained based on the updated state of charge value and the displayed state of charge at the previous moment.

[0013] Secondly, embodiments of the present invention provide a current-free sampling lithium battery state-of-charge estimation system, the system comprising: The data acquisition module is used to acquire the current operating data and the remaining capacity of the target battery pack at the previous moment; the current operating data includes cell voltage and battery temperature. The estimation boundary determination module is used to determine the current estimation boundary state range based on the cell voltage, the battery temperature, the remaining capacity at the previous moment, and a preset open-circuit voltage-remaining capacity mapping relationship; the current estimation boundary state range includes the current estimation voltage range and the current estimation remaining capacity range; The state of charge analysis module is used to perform linear interpolation based on the cell voltage and the current estimated boundary state range to obtain the current remaining battery capacity, and to perform state of charge analysis based on the current remaining battery capacity to obtain the current state of charge. The battery status analysis module is used to perform battery status analysis based on the current remaining battery capacity and historical cell voltage time-series data to obtain the current battery status. The state of charge display module is used to correct the state of charge display based on the current battery state, the current state of charge, and a preset state of charge monotonicity constraint, so as to obtain the target battery state of charge.

[0014] Thirdly, embodiments of the present invention also provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method.

[0015] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described method.

[0016] This invention provides a method, system, computer device, and storage medium for estimating the state of charge (SOC) of a lithium battery without current sampling. The method acquires the current operating data of the target battery pack, including cell voltage and battery temperature, and the remaining capacity at the previous moment. Based on the current operating data, the remaining capacity at the previous moment, and a preset open-circuit voltage-remaining capacity mapping relationship, it determines the current estimated boundary state range, including the current estimated voltage range and the current estimated remaining capacity range. Then, it performs linear interpolation based on the cell voltage and the current estimated boundary state range to obtain the current remaining battery capacity. Based on the current remaining battery capacity, it performs SOC analysis to obtain the current SOC. Finally, it performs battery state analysis based on the current remaining battery capacity and historical cell voltage time-series data to obtain the current battery state. Finally, it performs SOC display correction based on the current battery state, the current SOC, and a preset SOC monotonicity constraint to obtain the target battery's SOC. Compared with existing technologies, this current-sampling-free lithium battery state of charge estimation method uses a state of charge estimation mechanism that estimates the state of charge based on voltage and temperature combined with the estimated boundary state range, and performs state of charge display correction based on battery state. Under low-cost battery management conditions without current sampling, it can achieve state of charge estimation that conforms to actual capacity changes and suppresses reverse drift, effectively meeting the dynamic tracking requirements of accurate, stable, reliable, and user-friendly state of charge. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the method for estimating the state of charge of a lithium battery without current sampling in an embodiment of the present invention. Figure 2 This is a schematic diagram of the execution logic of the preset state change mechanism in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the lithium battery state-of-charge estimation system without current sampling in an embodiment of the present invention; Figure 4 This is an internal structural diagram of the computer device in an embodiment of the present invention; The attached figures are labeled as follows: 1. Data acquisition module; 2. Estimation boundary determination module; 3. State of charge analysis module; 4. Battery state analysis module; 5. State of charge display module. Detailed Implementation

[0018] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described below are only part of the embodiments of this invention and are used to illustrate the invention, but are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0019] The current-sampling-free lithium battery state-of-charge estimation method provided by this invention can be understood as addressing the current state of SOC estimation, which relies heavily on current sampling, involves large computational loads, and suffers from reverse drift. This results in an inability to meet the requirements of accurate, stable, and user-friendly dynamic SOC tracking within low-cost management platforms with limited hardware resources. Therefore, this invention proposes a method for estimating and displaying SOC under current-sampling-free conditions. This method uses a real-time estimation of boundary states based on voltage and temperature signals to accurately reflect actual battery capacity changes and suppress reverse drift. It is applicable to low-cost BMS systems without current sampling. The following embodiments will provide a detailed description of the current-sampling-free lithium battery state-of-charge estimation method of this invention.

[0020] In one embodiment, such as Figure 1 As shown, a method for estimating the state of charge of a lithium battery without current sampling is provided, including: S11. Obtain the current operating data and the remaining capacity of the target battery pack at the previous moment; wherein, the target battery pack is the battery pack that needs to be dynamically tracked for the state of charge in actual applications; the corresponding current operating data can be understood as the operating state of the target battery pack obtained based on the state of charge estimation cycle. In order to achieve state of charge estimation without current sampling, this embodiment preferably sets the current operating data to include cell voltage and battery temperature, and the cell voltage can be understood as the average voltage of all cells in the target battery pack, which can be obtained based on the ratio of the total voltage of the battery pack to the number of cells connected in series in the battery pack. The battery temperature can be expressed by the battery surface temperature or the cell center temperature, etc., without specific limitation here.

[0021] In this embodiment, the remaining capacity at the previous moment can be understood as the remaining battery capacity corresponding to the previous state of charge estimation cycle. In principle, the remaining battery capacity stored in the previous state of charge estimation cycle can be directly used. However, considering that in practical applications, the BMS system may encounter situations where it cannot effectively obtain stored information due to hardware-level problems (e.g., physical damage, power supply abnormalities, and communication signal abnormalities) or software and data logic-level problems (e.g., data storage management errors, invalid data), in order to ensure the efficiency and reliability of state of charge estimation, this embodiment preferably adopts a dual-path fault-tolerant mechanism of storage reading and analysis based on the open-circuit voltage remaining capacity mapping relationship to reduce the risk of single-point failure. Specifically, the steps for obtaining the remaining capacity at the previous moment include: The previous state of charge is read from the preset storage medium; the preset storage medium can be understood as the EEP or FLASH storage medium in the BSM system, and is not specifically limited here; the corresponding previous state of charge can be understood as the state of charge value obtained from the previous state of charge estimation period.

[0022] When the previous state of charge is successfully read, the available remaining capacity is analyzed based on the previous state of charge, maximum battery capacity, top reserved capacity, and bottom reserved capacity to obtain the remaining capacity at the previous moment. The maximum battery capacity, top reserved capacity, and bottom reserved capacity are set based on the actual target battery pack configuration, and the corresponding remaining capacity at the previous moment can be expressed as: In the formula, = The maximum battery capacity of the target battery pack, i.e., the maximum usable capacity of the battery. Reserved capacity at the top, i.e., the capacity value reserved at the top of the battery; Reserved capacity at the bottom, i.e., the capacity value reserved at the bottom of the battery; This represents the total available battery capacity. Estimate the time for the current state of charge; For a moment The corresponding state of charge at the previous moment; For a moment The remaining capacity at the previous time step.

[0023] When the previous state of charge reading fails, the first stable cell voltage is obtained, and the remaining capacity at the previous moment is obtained according to the mapping relationship between the first stable cell voltage and the preset open-circuit voltage remaining capacity. The first stable cell voltage can be understood as the average cell voltage under the first stable voltage state obtained within the current state of charge estimation period, which is obtained based on the ratio of the first stable battery pack total voltage to the number of cells in series in the battery pack.

[0024] The preset open-circuit voltage remaining capacity mapping relationship in this embodiment can be understood as a data table constructed based on existing open-circuit voltage tests, used to describe the correspondence between different open-circuit voltages and battery remaining capacity. In practical applications, the corresponding remaining capacity value can be obtained by looking up this data table based on the voltage. If the voltage of the first stable cell is a voltage data point in the data table, the remaining capacity value corresponding to that voltage data point is directly obtained as the required remaining capacity at the previous moment. If the voltage of the first stable cell is located between two voltage data points in the data table, the required remaining capacity at the previous moment can be calculated by the following linear interpolation: In the formula, This is the first stable cell voltage; and These are the lower and upper voltage limits of the first stable cell voltage in the preset open-circuit voltage-remaining capacity mapping relationship; To and The corresponding lower limit of remaining capacity value; To and The corresponding upper limit of remaining capacity; This is the remaining capacity obtained from the previous moment when the state of charge reading failed.

[0025] The dual-path fault-tolerant mechanism provided in this embodiment, which uses storage reading and analysis based on the open-circuit voltage remaining capacity mapping relationship, can not only efficiently provide continuous historical remaining capacity based on the storage medium when the BMS system is running continuously, but also directly use the inherent physical characteristics of the battery to give a reliable remaining capacity estimate when storage reading fails. This avoids dependence on the reliability and data integrity of the storage medium, reduces the risk of single-point failure, and provides an effective analytical basis for the efficiency and reliability of state of charge estimation.

[0026] S12. Determine the current estimated boundary state range based on the cell voltage, battery temperature, remaining capacity at the previous moment, and the preset open-circuit voltage-remaining capacity mapping relationship. The current estimated boundary state range can be understood as the voltage boundary and remaining capacity boundary applicable to the current state of charge estimation cycle, and may include the current estimated voltage range and the current estimated remaining capacity range. The current estimated voltage range includes an estimated voltage start point and an estimated voltage end point, and the current estimated remaining capacity range includes an estimated remaining capacity start point and an estimated remaining capacity end point. It should be noted that in practical applications, the scenarios requiring dynamic state of charge estimation are mainly battery charging and battery discharging scenarios: for battery charging scenarios, the estimated voltage end point is greater than the calculated voltage start point, and the estimated remaining capacity end point is greater than the estimated remaining capacity start point; for battery discharging scenarios, the estimated voltage end point is less than the calculated voltage start point, and the estimated remaining capacity end point is less than the estimated remaining capacity start point.

[0027] To ensure the effectiveness and efficiency of determining the current estimated boundary state range, this embodiment preferably uses the current cell voltage and battery temperature, the remaining capacity from the previous moment, and the current charging / discharging direction to iteratively estimate the endpoint boundary state. Specifically, the step of determining the current estimated boundary state range based on the current operating data, the remaining capacity from the previous moment, and the preset open-circuit voltage-remaining capacity mapping relationship includes: When it is determined that the estimated boundary state range needs to be updated based on the cell voltage and the estimated voltage range at the previous moment, the cell voltage and the remaining capacity at the previous moment are updated to the corresponding estimated voltage start point and estimated remaining capacity start point, respectively. In practical applications, it can be determined that the estimated boundary state range needs to be updated if any of the following conditions are met: 1) Perform the initial state-of-charge estimation after the system is powered on; 2) The cell voltage crosses the intermediate voltage value between the estimated voltage start and estimated voltage end points of the previous moment. The corresponding logical expression is as follows: In the formula, in, This is an indicator of whether the estimated boundary state range needs to be updated; a value of 1 indicates that an update is needed, and a value of 0 indicates that an update is not needed. Estimate the time for the current state of charge The cell voltage; , and Each is the previous moment The estimated voltage start point, estimated voltage end point, and corresponding intermediate voltage value; 3) The battery pack voltage remained stable for a certain period of time (30 minutes).

[0028] When the estimated boundary state range needs to be updated based on the above method steps, the current cell voltage and the remaining capacity at the previous moment are respectively used as the estimated voltage starting point in the current estimated voltage range and the estimated remaining capacity starting point in the current estimated remaining capacity range. It should be noted that when the state of charge estimation is performed for the first time after the system is powered on and initialized, the estimated remaining capacity starting point is set to the corresponding initial remaining capacity value, and the initial remaining capacity value can also be implemented by referring to the aforementioned technique for obtaining the remaining capacity at the previous moment, which will not be elaborated here.

[0029] Based on the estimated remaining capacity starting point and the preset open-circuit voltage remaining capacity mapping relationship, the corresponding estimated open-circuit voltage starting point is obtained; wherein, the process of obtaining the estimated open-circuit voltage starting point based on the preset open-circuit voltage remaining capacity mapping relationship can refer to the above-mentioned specific implementation description of obtaining the remaining capacity at the previous moment based on the first stable cell voltage and the preset open-circuit voltage remaining capacity mapping relationship, and will not be repeated here.

[0030] The current charging / discharging direction is determined based on the relationship between the cell voltage and the estimated open-circuit voltage start point. In practical applications, if the cell voltage is greater than or equal to the estimated open-circuit voltage start point within the current estimated voltage range, the current charging / discharging direction is determined to be the charging direction; otherwise, the current charging / discharging direction is determined to be the discharging direction.

[0031] Based on the current charging / discharging direction, the battery temperature, the estimated remaining capacity starting point, and a preset correction ratio, an iterative estimation of the endpoint boundary state is performed to update the estimated voltage endpoint and the estimated remaining capacity endpoint. The endpoint boundary state iterative estimation can be understood as iteratively updating the estimated remaining capacity endpoint based on the current charging direction according to a preset correction ratio, and then estimating and updating the estimated voltage endpoint based on the updated estimated remaining capacity endpoint, until a preset iterative estimation termination condition corresponding to the current charging / discharging direction is reached, thus determining the final estimated voltage endpoint and estimated remaining capacity endpoint.

[0032] Specifically, the step of iteratively estimating the endpoint boundary state based on the current charging / discharging direction, the battery temperature, the estimated remaining capacity starting point, and a preset correction ratio, and updating the estimated voltage endpoint and the estimated remaining capacity endpoint, includes: The starting point for estimating the remaining capacity is set as the initial value for the iteration of the ending point for estimating the remaining capacity. The capacity correction step size is determined based on the preset correction ratio and the maximum battery capacity. The preset correction ratio can be understood as a capacity threshold for incrementally correcting the lower boundary of the estimated remaining capacity. Its function is to provide an appropriate search step size for remaining capacity estimation in each iteration, balancing iteration convergence speed and estimation accuracy. This ratio is not fixed and can be adjusted according to the battery capacity scale, capacity dispersion, estimation accuracy requirements, and iteration stability requirements. This is to avoid the risk of reduced iteration convergence speed due to an excessively small preset correction ratio, or the risk of estimation deviation or oscillation due to an excessively large preset correction ratio. Preferably, in this embodiment, the preset correction ratio is set to 2%. The corresponding capacity correction step size can be understood as the product of the preset correction ratio and the maximum battery capacity.

[0033] Based on the initial iteration value and the capacity correction step size, a step update corresponding to the current charging / discharging direction is performed on the estimated remaining capacity endpoint to obtain the corresponding iterative estimated remaining capacity endpoint; wherein, the iterative estimated remaining capacity endpoint is represented as follows: 1) When the current charging / discharging direction is the discharging direction, we have: In the formula, and The first Wheel and First The endpoint of the iterative estimation of remaining capacity obtained from round-by-round iterative estimation, when hour, Used as the initial value for iteration; The maximum battery capacity of the target battery pack; This is the preset correction ratio; This is the step size for capacity correction.

[0034] 2) When the current charging / discharging direction is the charging direction, then: In the formula, and The first Wheel and First The endpoint of the iterative estimation of remaining capacity obtained from round-by-round iterative estimation, when hour, This is the initial value for the iteration.

[0035] Based on the iteratively estimated remaining capacity endpoint and the battery temperature, a voltage endpoint is estimated to obtain the corresponding iteratively estimated voltage endpoint. Then, it is determined whether a preset iterative estimation termination condition is met based on the iteratively estimated voltage endpoint. Specifically, voltage endpoint estimation can be understood as a process of estimating the corresponding open-circuit voltage based on the open-circuit voltage-remaining capacity mapping relationship and the mapping relationship between temperature, remaining capacity, and voltage change, using the iteratively estimated remaining capacity endpoint and the battery temperature. The step of estimating the voltage endpoint based on the iteratively estimated remaining capacity endpoint and the battery temperature to obtain the corresponding iteratively estimated voltage endpoint includes: Based on the iterative estimation of remaining capacity endpoint and the preset open-circuit voltage remaining capacity mapping relationship, the corresponding iterative static open-circuit voltage is obtained. The iterative static open-circuit voltage can be obtained by querying the preset open-circuit voltage remaining capacity mapping relationship using the iterative estimation of remaining capacity endpoint. The specific implementation process can be referred to the relevant description of obtaining the remaining capacity at the previous moment based on the first stable cell voltage given above, which will not be detailed here.

[0036] Based on the battery temperature, the endpoint of the iterative estimation of remaining capacity, the current charging / discharging direction, and the preset voltage change mapping table, the iterative static open-circuit voltage change is obtained; wherein, the preset voltage change mapping table may include a discharge direction voltage change mapping table and a charging direction voltage change mapping table, and both the discharge direction voltage change mapping table and the charging direction voltage change mapping table can be understood as the mapping relationship between battery temperature, remaining capacity, and voltage change under the corresponding charging / discharging direction.

[0037] The discharge direction voltage change mapping table in the preset voltage change mapping table can be constructed through the following testing and parameter extraction steps: 1) The test steps include: fully charging the test battery pack of the same model as the target battery pack at room temperature to ensure consistent initial state of charge; placing the battery in a temperature chamber with the temperature set at [-10℃, 0℃, 10℃, 25℃, 40℃] and letting it stand until the battery temperature stabilizes at the ambient temperature. The temperature range is selected according to the actual working environment of the battery and can cover all operating conditions of the battery; continuously discharging the battery at different discharge rates (e.g., 0.5C, 1C, 1.5C) and collecting the voltage, current and battery temperature data of the test battery pack over time. The discharge rate can be determined according to the load range of the battery under actual working conditions.

[0038] 2) The parameter extraction steps include: on each continuous discharge curve, using the total discharge capacity... To determine the capacity correction step size, an analysis step selection is performed to obtain the release step size. Remaining capacity ,temperature ,Voltage Current ,in The selection can be made by considering chip resources and the voltage characteristics of the battery cell, as long as it remains consistent with the selection of the aforementioned preset correction ratio; for each point, calculate the voltage change of the battery terminal voltage relative to the corresponding static open-circuit voltage at that capacity point. : In the formula, This refers to the aforementioned preset open-circuit voltage and remaining capacity mapping relationship.

[0039] The voltage variation at different discharge rates at each capacity point is averaged to obtain the final value. : In the formula, , and The currents are respectively , and The voltage change corresponding to the static open-circuit voltage under certain conditions.

[0040] By summarizing the average voltage changes obtained under the above discharge scenarios for each temperature, remaining capacity, and rate, a voltage change mapping table for the discharge direction can be obtained. Similarly, the voltage change mapping table for the charging direction was obtained using the standard battery charging method (0.5C) at room temperature. The parameter extraction steps are the same as those for the voltage change in the discharge direction, and will not be detailed here.

[0041] In practical applications, the required iterative static open-circuit voltage change can be obtained by directly querying the corresponding preset voltage change mapping table based on the battery temperature, the endpoint of the iterative estimation of remaining capacity, and the current charging / discharging direction. This will not be elaborated here.

[0042] The iteratively estimated open-circuit voltage is corrected based on the iterative change in static open-circuit voltage to obtain the corresponding iteratively estimated voltage endpoint; wherein, the calculation of the iteratively estimated voltage endpoint varies depending on the current charging / discharging direction, and is expressed as follows: 1) When the current charging / discharging direction is the discharging direction, we have: In the formula, and The first The iterative static open-circuit voltage and the change in iterative static open-circuit voltage obtained from round-by-round estimation; No. The endpoint of the iteratively estimated voltage obtained from round-by-round iterative estimation.

[0043] 2) When the current charging / discharging direction is the charging direction, then: In the formula, and The first charging scenario The iterative static open-circuit voltage and the change in iterative static open-circuit voltage obtained from round-by-round estimation; No. The endpoint of the iteratively estimated voltage obtained from round-by-round iterative estimation.

[0044] The embodiment provides a mapping relationship between open-circuit voltage and remaining capacity to determine the static open-circuit voltage. Combined with an estimated voltage endpoint iterative update mechanism that corrects the change in static open-circuit voltage based on charging / discharging direction, battery temperature, and remaining capacity, it not only considers the influence of temperature on voltage changes but also avoids battery polarization effects, effectively ensuring the reliability and accuracy of the estimated voltage endpoint iterative update.

[0045] When the conditions are met, the estimated remaining capacity endpoint and the estimated voltage endpoint are obtained according to the preset termination boundary determination rule of the iterative estimated remaining capacity endpoint and the iterative estimated voltage endpoint; wherein, the preset termination boundary determination rule can be understood as setting the update method of the estimated remaining capacity endpoint and the estimated voltage endpoint based on satisfying different iterative termination conditions.

[0046] If the condition is not met, update the initial value of the iteration based on the endpoint of the remaining capacity estimation in the iteration and continue the iteration estimation.

[0047] In practical applications, after obtaining the endpoint of the estimated voltage for each round through the above methods and steps, it is necessary to perform iteration termination detection based on the following preset iteration estimation termination conditions: 1) When the current charging / discharging direction is the discharging direction, the iterative estimation of the current estimated boundary state range is considered complete if any of the following conditions are met: a) When the estimate is obtained When the voltage is below the full discharge voltage threshold of a single cell, the iteration is considered complete. The estimated voltage endpoint is set to the full discharge voltage threshold of the single cell, and the estimated remaining capacity endpoint is set to the bottom reserved capacity value, thus obtaining the required current estimated boundary state range. b) When the estimation is obtained satisfy When the boundary update endpoint is reached, the iteration is considered complete, and the endpoints of the iterative estimation of remaining capacity and voltage obtained in the current iteration are taken as the corresponding endpoints of the estimated remaining capacity and estimated voltage, respectively; where, This is a voltage interval threshold used to limit... and The minimum voltage difference between the two thresholds is used to ensure sufficient voltage variation during the estimation of remaining capacity. This threshold can be configured or adaptively adjusted according to specific application scenarios to achieve a trade-off between suppressing misjudgments caused by short-term voltage fluctuations and ensuring estimation accuracy. Preferably, it is set to... =15.

[0048] 2) When the current charging / discharging direction is the charging direction, the iterative estimation of the current estimated boundary state range is considered complete if any of the following conditions are met: a) When the estimate is obtained When the full charge voltage threshold of a single cell is exceeded, the iteration is considered complete. The estimated voltage endpoint is set to the full charge voltage threshold of the single cell, and the estimated remaining capacity endpoint is set to the total available battery capacity (calculated based on the maximum battery capacity, top reserved capacity, and bottom reserved capacity), thus obtaining the required current estimated boundary state range.

[0049] b) When the estimation is obtained satisfy Once the boundary update endpoint is reached, the iteration is completed, and the endpoints of the iterative estimation of remaining capacity and voltage obtained in the current iteration are taken as the corresponding endpoints of the estimated remaining capacity and estimated voltage, respectively.

[0050] The current estimated voltage range is obtained based on the updated estimated voltage start point and the estimated voltage end point, and the current estimated remaining capacity range is obtained based on the updated estimated remaining capacity start point and the estimated remaining capacity end point.

[0051] The boundary state estimation mechanism adopted in this embodiment, which considers the effects of charging / discharging direction and temperature, can not only control the adjustment range of each iteration calculation based on a fixed capacity correction step size, avoiding endpoint jumps caused by single estimation deviations and achieving smooth convergence, but also adjust the step direction according to the charging / discharging direction to ensure the correct physical meaning of the iteration and avoid accuracy loss caused by reverse correction. Furthermore, by introducing temperature compensation and updating the endpoints of the iteratively estimated voltage and the iteratively estimated remaining capacity synchronously, it can ensure that the estimated results of voltage and remaining capacity are consistent with the battery characteristics, avoiding physically infeasible solutions. Thus, a good balance is achieved between computational complexity and estimation accuracy, providing a stable and reliable boundary state estimation capability for the battery management system.

[0052] S13. Perform linear interpolation based on the cell voltage and the current estimated boundary state range to obtain the current remaining battery capacity, and perform state of charge analysis based on the current remaining battery capacity to obtain the current state of charge; wherein, the current remaining battery capacity can be understood as the current capacity calculated by interpolating the cell voltage at the current moment based on the characteristic that voltage and remaining capacity have an approximately linear relationship within a small interval, and can be expressed as: In the formula, in, Estimate the time for the current state of charge The current remaining battery capacity; and The estimated time for the current state of charge is respectively The starting and ending points of the current estimated voltage range; and The estimated time for the current state of charge is respectively The current estimated remaining capacity range includes the starting point and the ending point of the estimated remaining capacity. This represents the average slope of the capacity change with voltage within the current estimated voltage range.

[0053] Based on the current remaining battery capacity, the corresponding current state of charge can be obtained using the following formula: In the formula, = = in, , and These are the target battery pack's maximum battery capacity, top reserved capacity, and bottom reserved capacity, respectively. This represents the total available battery capacity. and The estimated time for the current state of charge is respectively The current remaining battery capacity and the real-time remaining battery pack capacity; Estimate the time for the current state of charge The current state of charge.

[0054] S14. Analyze the battery state based on the current remaining battery capacity and historical cell voltage time-series data to obtain the current battery state. The current battery state can be understood as the battery state at the estimated current state of charge, determined by analyzing the battery voltage change characteristics based on the current remaining battery capacity and battery voltage change data extracted from historical cell voltage time-series data using a state machine control and a sliding time window. In this embodiment, the battery state may include: the battery or voltage state cannot be determined; the battery is in a static state and its state is stable; the battery is in a static state and its state is unstable; the battery is in a discharging state and its state is stable; the battery is in a discharging state and its state is unstable; the battery is in a charging state and its state is stable; and the battery is in a charging state and its state is unstable.

[0055] To ensure the reliability and rationality of determining the current battery state, this embodiment preferably employs a two-layer state analysis mechanism: instantaneous state analysis based on the deviation between the static open-circuit voltage and the cell voltage under charge / discharge conditions, combined with long-term battery state analysis using historical cell voltage time-series data. Specifically, the step of obtaining the current battery state by performing battery state analysis based on the current remaining battery capacity and historical cell voltage time-series data includes: Based on the current remaining battery capacity, the corresponding idle open-circuit voltage is obtained, and the cell voltage is analyzed based on the idle open-circuit voltage to obtain the corresponding instantaneous battery state. The idle open-circuit voltage can be understood as a voltage value obtained by querying a preset open-circuit voltage-remaining-capacity mapping relationship based on the current remaining battery capacity. The process of obtaining the corresponding instantaneous battery state may include: when the cell voltage is less than the difference between the idle open-circuit voltage and the minimum identifiable voltage deviation under the corresponding discharge condition, the instantaneous battery state is set to the battery being in a discharging state and unstable; when the cell voltage is greater than the sum of the idle open-circuit voltage and the minimum identifiable voltage deviation under the corresponding charging condition, the instantaneous battery state is set to the battery being in a charging state and unstable; otherwise, the instantaneous battery state is set to the battery being in an idle state and unstable. It should be noted that the magnitudes of the minimum identifiable voltage deviation under the discharge condition and the minimum identifiable voltage deviation under the charging condition can be set according to the charge / discharge rate range of the battery under normal operating conditions. For example, the minimum identifiable voltage deviation under the discharge condition is set to 25, and the minimum identifiable voltage deviation under the charging condition is set to 20.

[0056] According to a preset state change mechanism, voltage change characteristic analysis is performed on the historical cell voltage time series data to obtain the long-term battery state. The preset state change mechanism includes determining the voltage stability state and battery charge / discharge state based on the voltage change amplitude extracted using a sliding time window. In practical applications, the process of analyzing historical cell voltage time series data based on the preset state change mechanism to obtain the long-term battery state is as follows: Figure 2 As shown, it includes: 1. When the system is initially powered on, it first enters an undetermined state, setting the battery status to "unable to determine the battery or voltage status".

[0057] 2. Perform voltage stability assessment in situations where the outcome cannot be determined; define the voltage change amplitude as: In the sliding time window ( ),Right now Within each sampling period, if the following condition is met, the voltage is considered to be stable; otherwise, it remains in an undetermined state: in, The voltage stability threshold is preferably set to [value]. .

[0058] 3. After determining that the voltage has stabilized, determine the voltage trend: 1) In the sliding time window ( ),Right now Within each sampling period, if the following conditions are met, the voltage is considered to be stabilizing and enters the stabilization judgment state; otherwise, it cannot enter the stabilization judgment state. in, The voltage stability threshold during rest is preferably set to [value]. .

[0059] 2) If the condition that the voltage tends to stabilize at rest is not met, then for three consecutive time windows... ( Voltage trend determination is performed, with the corresponding number of sampling points being [number missing]. For each item, perform the following judgment: If in three consecutive time windows Inside, the cell voltage increases window by window, and the increments are all greater than 100%. If the voltage is considered to be rising and the battery is in the charging process, the battery state is set to be in the charging state and the state is unstable. If in three consecutive time windows Inside, the cell voltage decreases window by window, and the decrease is greater than [amount missing]. If the voltage is considered to be decreasing and the battery is in the process of discharging, then the battery state is set as being in a discharging state and the state is unstable.

[0060] If the above two conditions are not met, the battery will remain in an undetermined state, and the battery status will remain as if the battery or voltage status is undetermined.

[0061] 4. If the charging determination state is entered, the following judgments are made: Define the sliding time window length as ( The corresponding number of sampling points is One, in the sliding time window If the cell voltage drop is greater than the voltage stability threshold, then... (typical value) ): If the charging determination state is not met, the system will exit the charging determination state and enter the undeterminable state, maintaining the battery status as undetermined, indicating that the battery or voltage status is uncertain. If the above exit conditions are not met and the condition persists for the first duration ( If the battery status is set to "charged and stable", then the battery status will be set to "charged and stable".

[0062] 5. If the discharge determination state is entered, the following judgments are made: Define the sliding time window length as ( The corresponding number of sampling points is One, in the sliding time window If the cell voltage rise is greater than the voltage stability threshold, then... (typical value) ): If the discharge determination state is not met, the system will exit the discharge determination state and enter the undeterminable state, setting the battery status to "unable to determine the battery or voltage status." If the above exit conditions are not met and the condition persists for the first duration ( If the battery state is set to be in a discharging state and the state has stabilized, then the battery state will be set to be in a discharging state.

[0063] 6. If the system enters a static electrical state, the length of the sliding time window is defined as follows: ( The corresponding number of sampling points is For each item, perform the following judgment: In the sliding time window If the cell voltage rise is greater than the voltage stability threshold, then... (typical value) ): If the condition is met, the system exits the static state and enters the charging state, setting the battery status to be in a charging state but unstable; within the sliding time window... If the cell voltage drop is greater than the voltage stability threshold, then... : If the static condition is not met, the system exits the static condition determination state and enters the discharge condition determination state, setting the battery status to be in a discharge state and stable. If the aforementioned two exit conditions are not met, and the condition persists for the second duration ( If ), then the battery state is set to the battery being in a static state and the state is stable.

[0064] By combining the above-mentioned state machine control with the method of analyzing and extracting voltage change characteristics from historical cell voltage time-series data based on a sliding time window, the long-term state of the battery that closely matches the actual battery operating conditions can be obtained efficiently and reliably.

[0065] The current battery state is obtained by performing a comprehensive state analysis based on the instantaneous and long-term states of the battery. This comprehensive state analysis can be understood as determining which state to use as the current battery state based on the priorities corresponding to the instantaneous and long-term states. In practical applications, the various battery states can be prioritized in advance, with higher priorities indicating more reliable state determination results: states that are stable (steady-state) are assigned the highest priority (3), states that are unstable (non-steady-state) are assigned the next highest priority (2), and states that are undetermined (unknown) are assigned the lowest priority (1). Based on this priority division method, after obtaining the state priorities corresponding to the instantaneous and long-term states, the priorities of the instantaneous and long-term states are compared. The state with the higher priority is determined as the final current battery state. That is, if the state priority of the instantaneous state is greater than or equal to the state priority of the long-term state, the current battery state is set as the instantaneous state; otherwise, the current battery state is set as the long-term state.

[0066] This embodiment employs a dual-layer state analysis mechanism: instantaneous state analysis based on the deviation between the static open-circuit voltage and the cell voltage under charge / discharge conditions; and long-term battery state analysis based on battery voltage change data extracted from historical cell voltage time-series data using a sliding time window. This mechanism not only rapidly reflects the battery's current operating state by utilizing its inherent electrochemical characteristics but also reliably identifies the stable voltage state, charge / discharge process, and abnormal fluctuations based on the voltage change amplitude. This overcomes the limitations of single instantaneous signals being susceptible to load mutations and polarization effects, effectively ensuring the accuracy, robustness, and comprehensiveness of battery state identification, reducing the risk of misjudgment, and providing a reliable analytical basis for subsequent state-of-charge display correction.

[0067] S15. Correct the state of charge (SOC) display based on the current battery state, the current state of charge (SOC), and a preset SOC monotonicity constraint to obtain the target battery SOC. The preset SOC monotonicity constraint can be understood as a battery SOC display constraint based on the user's perception of SOC changes under charging and discharging conditions. Preferably, the preset SOC monotonicity constraint includes a monotonically increasing SOC during charging, a monotonically decreasing SOC during discharging, and a unchanged SOC during rest. Correspondingly, the target battery SOC can be understood as the final displayed battery SOC that effectively suppresses reverse SOC drift during charging and discharging while ensuring that SOC changes conform to the user's perception, based on the current battery state, the current SOC, and the preset SOC monotonicity constraint, thereby limiting the direction and magnitude of SOC display changes.

[0068] Specifically, the step of correcting the state of charge display based on the current battery state, the current state of charge, and a preset state of charge monotonicity constraint to obtain the target battery state of charge includes: The magnitude of the change in state of charge is obtained based on the difference between the current state of charge and the state of charge at the previous moment; wherein, the magnitude of the change in state of charge can be expressed as: In the formula, Estimate the time for the current state of charge The current state of charge; For a moment The corresponding state of charge at the previous moment; Estimate the time for the current state of charge The magnitude of the change in the state of charge.

[0069] Based on the current battery state, the magnitude of the state of charge change, and the preset monotonicity constraint of the state of charge, a state of charge update value is obtained; wherein, the process of obtaining the state of charge update value includes: If the current battery state is either the battery is in a charging state and the state has stabilized, or the battery is in a charging state and the state has not stabilized, then the updated state of charge value is... Represented as: ; If the current battery state is either a discharged state that has stabilized or a discharged state that has not stabilized, then the updated state of charge value is... Represented as: ; If the current battery state is one of the following: the battery or voltage state cannot be determined, the battery is in a quiescent state and its state has stabilized, or the battery is in a quiescent state and its state is unstable, then the updated state of charge value is... .

[0070] The target battery state of charge (SBC) is obtained based on the updated SBC value and the previously displayed SBC; wherein, the target battery SBC is the sum of the previously displayed SBC and the updated SBC value, and can be expressed as: In the formula, and The estimated time for the current state of charge is respectively The target battery state of charge and the displayed state of charge at the previous moment; Estimate the time for the current state of charge The updated value of the state of charge.

[0071] This embodiment applies a monotonicity constraint to the displayed State of Charge (SOC), ensuring that the direction of change under different battery states is consistent with the actual charging behavior of the battery: the displayed SOC monotonically increases during charging, monotonically decreases during discharging, and remains unchanged during rest. This avoids reverse drift under no-current conditions, ensuring that the displayed SOC still presents a true trend consistent with the user's intuitive understanding. It also prevents abnormal jumps in the displayed SOC due to transient noise or minor voltage fluctuations, thereby improving the stability and readability of the SOC display and providing reliable data support for the analysis and use of the battery management system.

[0072] This invention provides a technical solution for obtaining the current operating data of the target battery pack, including cell voltage and battery temperature, and the remaining capacity at the previous moment. Based on the current operating data, the remaining capacity at the previous moment, and a preset open-circuit voltage-remaining capacity mapping relationship, a current estimated boundary state range is determined, including the current estimated voltage range and the current estimated remaining capacity range. Then, linear interpolation is performed based on the cell voltage and the current estimated boundary state range to obtain the current battery remaining capacity. Based on the current battery remaining capacity, state of charge (SOC) analysis is performed to obtain the current SOC. Furthermore, based on the current battery remaining capacity and historical cell voltage time-series data, battery state analysis is performed to obtain the current battery state. Finally, SOC display correction is performed based on the current battery state, the current SOC, and a preset SOC monotonicity constraint to obtain the target battery SOC. This SOC estimation mechanism, based on voltage and temperature combined with the estimated boundary state range, and correcting the SOC display based on the battery state, can achieve SOC estimation that conforms to actual capacity changes and suppresses reverse drift under low-cost battery management conditions without current sampling. This effectively meets the dynamic tracking requirements of accurate, stable, reliable, and user-friendly SOC tracking.

[0073] It should be noted that although the steps in the flowchart above are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise explicitly stated in this document, there is no strict order requirement for the execution of these steps, and they can be executed in other orders.

[0074] In one embodiment, such as Figure 3 As shown, a current-free sampling lithium battery state-of-charge estimation system is provided, the system comprising: Data acquisition module 1 is used to acquire the current operating data and the remaining capacity of the target battery pack at the previous moment; the current operating data includes cell voltage and battery temperature; The estimation boundary determination module 2 is used to determine the current estimation boundary state range based on the cell voltage, the battery temperature, the remaining capacity at the previous moment, and the preset open-circuit voltage-remaining capacity mapping relationship; the current estimation boundary state range includes the current estimation voltage range and the current estimation remaining capacity range; The state of charge analysis module 3 is used to perform linear interpolation based on the cell voltage and the current estimated boundary state range to obtain the current remaining battery capacity, and to perform state of charge analysis based on the current remaining battery capacity to obtain the current state of charge. Battery status analysis module 4 is used to perform battery status analysis based on the current remaining battery capacity and historical cell voltage time series data to obtain the current battery status; The state of charge display module 5 is used to correct the state of charge display based on the current battery state, the current state of charge, and the preset state of charge monotonicity constraint, so as to obtain the target battery state of charge.

[0075] Specific limitations regarding the current-free sampling lithium-ion battery state-of-charge estimation system can be found in the limitations of the current-free sampling lithium-ion battery state-of-charge estimation method described above; the corresponding technical effects are equivalent and will not be repeated here. Each module in the aforementioned current-free sampling lithium-ion battery state-of-charge estimation system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0076] Figure 4 An internal structural diagram of a computer device is shown in one embodiment. This computer device may specifically be a terminal or a server. Figure 4As shown, the computer device includes a processor, memory, network interface, display, camera, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program can implement a method for estimating the state of charge of a lithium battery without current sampling. The display screen can be an LCD screen or an e-ink display. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0077] Those skilled in the art will understand that Figure 4 The structure shown is merely a block diagram of a portion of the structure related to the present invention and does not constitute a limitation on the computer device to which the present invention is applied. Specific computing devices may include more or fewer components than those shown in the figure, or combine certain components, or have the same component arrangement.

[0078] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0079] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0080] In summary, the present invention provides a method, system, computer device, and storage medium for estimating the state of charge (SOC) of a lithium battery without current sampling. This SOC estimation mechanism, which estimates the SOC based on voltage and temperature combined with the estimated boundary state range, and corrects the SOC display based on the battery state, enables SOC estimation that accurately reflects actual capacity changes and suppresses reverse drift under low-cost battery management conditions without current sampling. This effectively meets the dynamic tracking requirements of accurate, stable, reliable, and user-friendly SOC tracking.

[0081] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0082] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A method for estimating the state of charge of a lithium battery without current sampling, characterized in that, The method includes: Obtain the current operating data and the remaining capacity of the target battery pack at the previous moment. The current operating data includes cell voltage and battery temperature. Based on the cell voltage, the battery temperature, the remaining capacity at the previous moment, and the preset open-circuit voltage-remaining capacity mapping relationship, the current estimated boundary state range is determined, and the current estimated boundary state range includes the current estimated voltage range and the current estimated remaining capacity range. Linear interpolation is performed based on the cell voltage and the current estimated boundary state range to obtain the current remaining battery capacity, and state of charge analysis is performed based on the current remaining battery capacity to obtain the current state of charge. The current battery status is obtained by analyzing the current remaining battery capacity and historical cell voltage time-series data. The target battery state of charge is obtained by correcting the state of charge display based on the current battery state, the current state of charge, and the preset monotonicity constraint of the state of charge.

2. The method for estimating the state of charge of a lithium battery without current sampling as described in claim 1, characterized in that, The steps for obtaining the remaining capacity at the previous moment include: Read the charge state from the previous moment from the preset storage medium; When the previous state of charge is successfully read, the available remaining capacity is analyzed based on the previous state of charge, the battery maximum capacity, the top reserved capacity, and the bottom reserved capacity to obtain the remaining capacity at the previous moment. When the state of charge reading of the previous moment fails, the first stable cell voltage is obtained, and the remaining capacity of the previous moment is obtained according to the mapping relationship between the first stable cell voltage and the preset open circuit voltage remaining capacity.

3. The method for estimating the state of charge of a lithium battery without current sampling as described in claim 1, characterized in that, The current estimated voltage range includes the estimated voltage start point and the estimated voltage end point; the current estimated remaining capacity range includes the estimated remaining capacity start point and the estimated remaining capacity end point. The step of determining the current estimated boundary state range based on the cell voltage, the battery temperature, the remaining capacity at the previous moment, and the preset open-circuit voltage-remaining capacity mapping relationship includes: When it is determined that the estimated boundary state range needs to be updated based on the cell voltage and the estimated voltage range at the previous moment, the cell voltage and the remaining capacity at the previous moment are updated to the corresponding estimated voltage start point and estimated remaining capacity start point, respectively. Based on the estimated remaining capacity starting point and the preset open-circuit voltage remaining capacity mapping relationship, the corresponding estimated open-circuit voltage starting point is obtained; Based on the relationship between the cell voltage and the estimated open-circuit voltage start point, the current charging / discharging direction is obtained; Based on the current charging / discharging direction, the battery temperature, the estimated remaining capacity starting point, and the preset correction ratio, the endpoint boundary state is iteratively estimated, and the estimated voltage endpoint and the estimated remaining capacity endpoint are updated. The current estimated voltage range is obtained based on the updated estimated voltage start point and the estimated voltage end point, and the current estimated remaining capacity range is obtained based on the updated estimated remaining capacity start point and the estimated remaining capacity end point.

4. The method for estimating the state of charge of a lithium battery without current sampling as described in claim 3, characterized in that, The step of iteratively estimating the endpoint boundary state based on the current charging / discharging direction, the battery temperature, the estimated remaining capacity starting point, and a preset correction ratio, and updating the estimated voltage endpoint and the estimated remaining capacity endpoint, includes: The estimated remaining capacity starting point is set as the iteration initial value of the estimated remaining capacity ending point, and the capacity correction step size is determined according to the preset correction ratio and the maximum battery capacity. Based on the initial iteration value and the capacity correction step size, perform a step update corresponding to the current charging and discharging direction on the estimated remaining capacity endpoint to obtain the corresponding iterative estimated remaining capacity endpoint. Based on the remaining capacity endpoint of the iterative estimation and the battery temperature, the voltage endpoint is estimated to obtain the corresponding iterative estimated voltage endpoint, and it is determined whether the preset iterative estimation termination condition is met based on the iterative estimated voltage endpoint. When the conditions are met, the estimated remaining capacity endpoint and the estimated voltage endpoint are obtained according to the preset termination boundary determination rule of the iterative estimation of the remaining capacity endpoint and the iterative estimation of the voltage endpoint. If the condition is not met, update the initial value of the iteration based on the endpoint of the remaining capacity estimation in the iteration and continue the iteration estimation.

5. The method for estimating the state of charge of a lithium battery without current sampling as described in claim 4, characterized in that, The step of estimating the voltage endpoint based on the iteratively estimated remaining capacity endpoint and the battery temperature to obtain the corresponding iteratively estimated voltage endpoint includes: Based on the iterative estimation of the remaining capacity endpoint and the preset open-circuit voltage-remaining capacity mapping relationship, the corresponding iterative static open-circuit voltage is obtained; Based on the battery temperature, the endpoint of the iterative estimation of remaining capacity, the current charging / discharging direction, and the preset voltage change mapping table, the iterative static open-circuit voltage change is obtained; The iteratively set open-circuit voltage is corrected based on the change in the iteratively set open-circuit voltage to obtain the corresponding iteratively estimated voltage endpoint.

6. The method for estimating the state of charge of a lithium battery without current sampling as described in claim 1, characterized in that, The step of analyzing the battery status based on the current remaining battery capacity and historical cell voltage time-series data to obtain the current battery status includes: Based on the current remaining battery capacity, the corresponding static open-circuit voltage is obtained, and the cell voltage is analyzed based on the static open-circuit voltage to obtain the corresponding instantaneous battery state. According to the preset state change mechanism, the voltage change characteristics of the historical cell voltage time series data are analyzed to obtain the long-term state of the battery; the preset state change mechanism includes judging the voltage stability state and the battery charge and discharge state based on the voltage change amplitude extracted by the sliding time window. The current battery state is obtained by performing a comprehensive state analysis based on the instantaneous state and the long-term state of the battery.

7. The method for estimating the state of charge of a lithium battery without current sampling as described in claim 1, characterized in that, The preset state of charge monotonicity constraint includes a monotonically increasing state of charge during charging, a monotonically decreasing state of charge during discharging, and a state of charge remaining unchanged during rest. The step of correcting the state of charge display based on the current battery state, the current state of charge, and a preset state of charge monotonicity constraint to obtain the target battery state of charge includes: The magnitude of the change in charge state is obtained based on the difference between the current charge state and the charge state at the previous moment. The updated state of charge value is obtained based on the current battery state, the magnitude of the state of charge change, and the preset state of charge monotonicity constraint. The target battery state of charge is obtained based on the updated state of charge value and the displayed state of charge at the previous moment.

8. A current-free sampling lithium battery state-of-charge estimation system, characterized in that, The system includes: The data acquisition module is used to acquire the current operating data and the remaining capacity of the target battery pack at the previous moment; the current operating data includes cell voltage and battery temperature. The estimation boundary determination module is used to determine the current estimation boundary state range based on the cell voltage, the battery temperature, the remaining capacity at the previous moment, and a preset open-circuit voltage-remaining capacity mapping relationship; the current estimation boundary state range includes the current estimation voltage range and the current estimation remaining capacity range; The state of charge analysis module is used to perform linear interpolation based on the cell voltage and the current estimated boundary state range to obtain the current remaining battery capacity, and to perform state of charge analysis based on the current remaining battery capacity to obtain the current state of charge. The battery status analysis module is used to perform battery status analysis based on the current remaining battery capacity and historical cell voltage time-series data to obtain the current battery status. The state of charge display module is used to correct the state of charge display based on the current battery state, the current state of charge, and a preset state of charge monotonicity constraint, so as to obtain the target battery state of charge.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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