A state of charge estimation method, system, apparatus, device, and medium

Abstract

This application discloses a method, system, apparatus, device, and medium for estimating the state of charge (SOC). The method includes: acquiring the measurement current error of a target battery; correcting the measurement current of the target battery using the measurement current error to obtain a corrected current for the target battery; and determining the SOC of the target battery based on the corrected current. This approach can improve the accuracy of SOC estimation.

Description

Technical Field

[0001] This application relates to the field of batteries, and in particular to a method, system, apparatus, device, and medium for estimating the state of charge. Background Technology

[0002] State of Charge (SOC) refers to the ratio of a battery's remaining charge in its current state to its capacity in a fully charged state, and can be expressed as a percentage. SOC plays a crucial role as a battery's state parameter, for example, by analyzing battery performance and preventing battery failures.

[0003] However, current methods for estimating the state of charge (SOC) of batteries based on current are not very accurate. Improving the accuracy of SOC estimation is a pressing issue that needs to be addressed. Summary of the Invention

[0004] This application provides at least one method, system, apparatus, device, and medium for estimating the state of charge.

[0005] This application provides a method for estimating the state of charge (SOC), comprising: obtaining the measurement current error of a target battery; correcting the measurement current of the target battery using the measurement current error to obtain a corrected current of the target battery; and determining the SOC of the target battery based on the corrected current of the target battery.

[0006] In the above scheme, the measurement current error is obtained in advance, and the measurement current is corrected by using the measurement current error. The corrected current is closer to the actual output current of the battery. Based on the corrected current, the state of charge is estimated, which can improve the accuracy of the state of charge estimation.

[0007] In some embodiments, obtaining the measurement current error of the target battery includes: obtaining the cumulative capacity change of the target battery at at least one target time, the cumulative capacity change being determined based on the measurement current from the start time to the corresponding target time; and determining the measurement current error of the target battery based on the cumulative duration and the cumulative capacity change at at least one target time, the cumulative duration being the duration of the interval between the start time and the corresponding target time.

[0008] In the above scheme, the cumulative capacity change is obtained based on the measured current from the start time to the target time. It is related to the cumulative duration and the measurement current error. The measurement current error can be determined by using the cumulative capacity change and the cumulative duration, thereby improving the accuracy of the current characterization of the target battery.

[0009] In some embodiments, determining the measurement current error of a target battery based on the cumulative duration and cumulative capacity change corresponding to at least one target time includes: calculating the measurement current error based on the target mapping relationship, the cumulative duration and cumulative capacity change corresponding to each target time; the target mapping relationship characterizes the mapping relationship between the cumulative capacity change, the cumulative duration and the measurement current error.

[0010] In the above scheme, the target mapping relationship represents the mapping relationship between the cumulative capacity change, the cumulative duration, and the measurement current error. Thus, the measurement current error can be obtained by using the target mapping relationship, the cumulative duration, and the cumulative capacity change.

[0011] In some embodiments, the target mapping relationship characterizes the cumulative capacity change as a linear change with the cumulative duration, with the measurement current error serving as the linear coefficient.

[0012] In the above scheme, the linear coefficient between the cumulative duration and the cumulative capacity change is calculated using the cumulative duration and the cumulative capacity change at at least one target time, thereby determining the measurement current error.

[0013] In some embodiments, the target mapping relationship represents the cumulative capacity change as equal to the sum of the first product and the remaining capacity difference, where the first product is the product of the measurement current error and the cumulative duration, and the remaining capacity difference is the difference between the remaining capacity at the starting time and the remaining capacity at the corresponding target time.

[0014] In the above scheme, the target mapping relationship represents that the cumulative capacity change is equal to the product of the measurement current error and the cumulative duration plus the remaining capacity difference. By combining the cumulative duration and cumulative capacity change at at least one target time, the measurement current error can be solved.

[0015] In some embodiments, there are multiple target times; the measurement current error is calculated based on the target mapping relationship, the cumulative duration and cumulative capacity change corresponding to each target time, including: performing linear regression based on the cumulative duration and cumulative capacity change corresponding to multiple target times to obtain the measurement current error; or, selecting at least one pair of target times from multiple target times; for each pair of target times, calculating the rate of change of cumulative capacity change with cumulative duration, and determining the measurement current error based on the rate of change corresponding to each pair of target times.

[0016] In the above scheme, when there are multiple target times, linear regression can be performed or the rate of change between two target times can be calculated to obtain the measurement current error.

[0017] In some embodiments, before obtaining the cumulative capacity change of the target battery at at least one target time, the method further includes: determining the current time window at preset intervals; and selecting at least one target time from the current time window.

[0018] In the above scheme, the target time is reselected at preset intervals to obtain a new measurement current error, which can realize the updating of the measurement current error and improve the accuracy of the measurement current error determination.

[0019] In some embodiments, obtaining the cumulative capacity change of the target battery at at least one target time includes: obtaining the cumulative charging capacity and cumulative discharging capacity of the target battery at each target time; and for each target time, determining the cumulative capacity change at the target time based on the cumulative charging capacity and cumulative discharging capacity at the target time.

[0020] In the above scheme, the cumulative capacity change can be calculated based on the cumulative charging capacity and cumulative discharging capacity at the target time, and thus can be used to determine the error.

[0021] In some embodiments, obtaining the cumulative charging capacity and cumulative discharging capacity of the target battery at each target time includes: obtaining the measured current between each target time and the corresponding start time; and for each target time, calculating the cumulative charging capacity and cumulative discharging capacity at the target time based on the measured current between the target time and the corresponding start time.

[0022] In the above scheme, the cumulative charging capacity and cumulative discharging capacity can be calculated by measuring the current, which can then be used to determine the error.

[0023] This application provides a system for estimating the state of charge (SOC). The system includes a sampling device and a processing device. The sampling device acquires the measured current of a target battery, and the processing device executes any of the methods described above, or the sampling device and processing device cooperate to execute any of the methods described above. In this scheme, the sampling device and processing device work together to determine the error in the measured current of the target battery.

[0024] This application provides a state of charge (SOC) estimation device, including an acquisition module, a correction module, and a SOC estimation module. The acquisition module acquires the measurement current error of the target battery; the correction module corrects the measurement current of the target battery using the measurement current error to obtain the corrected current of the target battery; and the SOC estimation module determines the SOC of the target battery based on the corrected current of the target battery.

[0025] This application provides an electronic device, including a memory and a processor, wherein the memory stores program instructions, which, when executed by the processor, implement the method described in any of the above-mentioned embodiments.

[0026] This application provides a computer-readable storage medium having program instructions stored thereon, which, when executed by a processor, implement the method described in any of the above-described embodiments.

[0027] In the above scheme, the measurement current error is obtained in advance, and the measurement current is corrected by using the measurement current error. The corrected current is closer to the actual output current of the battery. Based on the corrected current, the state of charge is estimated, which can improve the accuracy of the state of charge estimation.

[0028] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this application. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0030] Figure 1 This is a flowchart illustrating the method for estimating the state of charge provided in some embodiments of this application;

[0031] Figure 2 This application Figure 1 Flowcharts of some embodiments of step S110;

[0032] Figure 3 This is a schematic diagram of a method for estimating the state of charge provided in other embodiments of this application;

[0033] Figure 4 This is a schematic diagram of the framework of a state of charge estimation system provided in some embodiments of this application;

[0034] Figure 5 This is a schematic diagram of the framework of a state of charge estimation device provided in some embodiments of this application;

[0035] Figure 6 This is a schematic diagram of the framework of an electronic device provided in some embodiments of this application;

[0036] Figure 7 This is a schematic diagram of the framework of a computer-readable storage medium provided in some embodiments of this application. Detailed Implementation

[0037] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0038] In the following description, specific details such as particular subsystem structures, interfaces, and technologies are presented for illustrative purposes rather than for limiting purposes, in order to provide a thorough understanding of this application.

[0039] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, "many" in this document means two or more. Moreover, the term "at least one" in this document means any combination of at least two of any one or more of a plurality of objects. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0040] State of charge (SCC) plays a crucial role as a battery's state parameter, serving purposes such as analyzing battery performance and preventing battery malfunctions. SCC can be estimated using measured battery parameters, such as current. However, current methods often differ between the measured current and the battery's actual output current, resulting in low accuracy for current-based SCC estimation. Therefore, this embodiment proposes a SCC estimation method that pre-acquires the measurement current error and uses this error to correct the measured current. The corrected current more closely approximates the battery's actual output current, and SCC estimation based on this corrected current improves the accuracy of SCC estimation.

[0041] The battery types to which the method for estimating the state of charge disclosed in this application is applicable are not limited here. For example, it may include lithium manganese iron phosphate batteries, etc.

[0042] Please see Figure 1 , Figure 1 This is a flowchart illustrating a method for estimating the state of charge (SOC) provided in some embodiments of this application. Specifically, the method includes:

[0043] Step S110: Obtain the measurement current error of the target battery.

[0044] The target battery is the object whose state of charge is to be estimated. The measurement current error is the error corresponding to the measured current.

[0045] Step S120: Correct the measured current of the target battery using the measurement current error to obtain the corrected current of the target battery.

[0046] The measured current can be obtained by collecting data from the target battery using a current acquisition device. There will be a certain difference between the measured current and the actual output current of the target battery. Understandably, there are various reasons for this difference, such as the self-discharge current affecting the measured current due to battery self-discharge, and errors in the current acquisition device.

[0047] Among them, the measurement current error can correct the above differences, and the corrected current can be closer to the actual output current of the target battery.

[0048] Step S130: Determine the state of charge of the target battery based on the corrected current of the target battery.

[0049] The corrected current can be used to determine the battery's state of charge. Since the corrected current is closer to the actual output current of the target battery, it can improve the accuracy of the state of charge estimation.

[0050] In some embodiments, the method for estimating the state of charge based on current may include, but is not limited to, the ampere-hour integral method, the Kalman filter method, etc. The input to the above algorithms includes the correction current.

[0051] Understandably, the current sampling device can continuously collect current data from the target battery. Specifically, the sampling time can be set, and data can be collected once at each sampling time. For example, data can be collected once at regular intervals. This continuous collection can be performed multiple times over time.

[0052] Each data acquisition moment corresponds to a measurement current error. The measurement current errors at different acquisition moments can be the same or different. For each acquisition moment, the measurement current at that moment can be corrected using the measurement current error corresponding to that moment, resulting in the corrected current for that moment.

[0053] Understandably, the state of charge (SOC) of a battery changes over time as it is either discharging or charging. Estimating the SOC of a target battery can be done by estimating the SOC at different times. For a specific moment, the corrected current from historical data can be used to determine the SOC at that moment.

[0054] In some embodiments, a state of charge estimation algorithm can be used to estimate the state of charge at a specific time. The input information of the state of charge estimation algorithm may include a target current at at least one time, and at least a portion of the target current included in the input information is a correction current.

[0055] In some implementation scenarios, the state of charge (SOC) of the target battery at the end of the target time period can be determined based on the initial SOC of the target battery during the target time period and the target current at several sampling moments within the target time period. In this case, the target current at at least some sampling moments is a correction current, obtained by correcting for the measurement current error at that moment. In some cases, if there is only one target current at a sampling moment, that current is the correction current. In other cases, there are multiple sampling moments, and all target currents can be used as correction currents, or some target currents may be the original measurement currents.

[0056] In a specific application scenario, the end time of the target time period can be the current time. The start time can be any time before the current time. The target current at several sampling times within the target time period can be used to determine the change in state of charge (ΔSOC) during the target time period. Combined with the initial state of charge, the state of charge at the current time can be obtained.

[0057] See Figure 2 , Figure 2 This application Figure 1 A flowchart illustrating some embodiments of step S110. Specifically, step S110 may include:

[0058] Step S211: Obtain the cumulative capacity change of the target battery at at least one target time.

[0059] The cumulative capacity change corresponding to each target time is determined based on the measured current from the start time to that target time. For each target time, the cumulative duration of that target time can also be calculated, which can be the duration between the start time and the target time.

[0060] In some embodiments, all target times may correspond to the same start time. In some embodiments, at least some target times may correspond to different start times.

[0061] In some implementation scenarios, there are multiple target times, and the cumulative capacity change at these multiple target times can correspond to at least two different cumulative durations. In some implementation scenarios, the cumulative capacity change at different target times corresponds to different cumulative durations. In some implementation scenarios, all target times correspond to at least two different cumulative durations.

[0062] Measuring the current of the target battery yields the measured current. Based on the measured current over a period of time, the cumulative capacity change during that period can be calculated.

[0063] In some embodiments, the target battery can be in a charging or discharging state at any given time, and the measured current at any given time is either the charging current or the discharging current. In the embodiments of this application, the charging current is positive, and the discharging current is negative. Accumulating the charging current yields the cumulative charging capacity, and accumulating the discharging current yields the cumulative discharging capacity. The cumulative charging capacity is positive, and the cumulative discharging capacity is negative. The change in cumulative capacity can be obtained based on the cumulative charging capacity and the cumulative discharging capacity.

[0064] In a specific application scenario, the cumulative capacity change can be the sum of the cumulative charging capacity and the cumulative discharging capacity.

[0065] Step S212: Determine the measurement current error of the target battery based on the cumulative duration and cumulative capacity change corresponding to at least one target time.

[0066] Each target time corresponds to its own cumulative duration and cumulative capacity change.

[0067] It is understandable that there will be some error in current measurement, which will lead to inaccuracy in the cumulative capacity change obtained based on the accumulated current measurement over a period of time. Therefore, the measurement current error can be derived by using the cumulative capacity change and the accumulation period.

[0068] In the above scheme, the cumulative capacity change is obtained based on the measured current from the start time to the target time. The cumulative capacity change is related to the cumulative duration and the measurement current error. The error in the measurement current can be inferred by using the cumulative capacity change, thereby improving the accuracy of the target battery's current and the accuracy of the target battery's characteristic characterization.

[0069] It is understandable that the target battery may have self-discharge, and the source of measurement current error may include self-discharge current.

[0070] Current is measured using a current sensor, and the sources of error in current measurement can include the measurement error of the current sensor itself. Specifically, the current value sampled by the current sensor generally has a certain error, and this error is usually a systematic error with a non-zero mean (i.e., "zero drift").

[0071] In some embodiments, there is a target mapping relationship between the cumulative capacity change, the cumulative duration, and the measurement current error. Therefore, based on the target mapping relationship and the cumulative duration and cumulative capacity change corresponding to each target time, the measurement current error can be calculated.

[0072] In some embodiments, the target mapping relationship can characterize the cumulative capacity change as a function of the cumulative duration, and the measurement current error is a linear coefficient that changes linearly.

[0073] Furthermore, the target mapping relationship includes multiple parameters. By substituting the parameters corresponding to a certain moment, the linear coefficient can be calculated. Alternatively, based on the cumulative capacity change corresponding to multiple different cumulative durations, the linear coefficient between the two can be calculated.

[0074] In some embodiments, different target times correspond to different cumulative durations, and linear coefficients can be obtained based on the cumulative capacity changes at multiple target times.

[0075] In some specific application scenarios, if the cumulative capacity change at multiple times corresponds to the same cumulative duration, the final cumulative capacity change corresponding to that cumulative duration can be determined based on these multiple cumulative capacity changes.

[0076] For the target battery, the actual cumulative charging capacity of the battery satisfies the following formula:

[0077] ∫I chr dt=∫-I dch dt+∫I slfdch dt+constant

[0078] The actual cumulative charging capacity is equal to the sum of the external circuit discharge capacity, self-discharge capacity, and capacity difference.

[0079] Among them, I chr Represents the charging current, I dch Represents the discharge current. I slfdch ∫I represents the self-discharge current, t represents time, and constant represents the capacity difference before and after charging and discharging due to the difference in state of charge. chr dt represents the actual cumulative charging capacity, ∫-I dch dt represents the discharge capacity of the external circuit, ∫I slfdch dt represents the self-discharge capacity.

[0080] At any given moment, the battery is in either a charging or discharging state, and the measured current is either the charging current or the discharging current. The self-discharge current is always present. The charging current and the corresponding charging time are used to calculate the cumulative charging capacity, and the discharging current and the corresponding discharging time are used to calculate the external circuit discharge capacity. The sum of the charging time and the discharging time is the cumulative duration.

[0081] For example, the state of charge (SBC) at the start time is 10%, and the SBC at the target time is 20%. The SBC between the target time and the start time differs by 10%. Accordingly, the remaining capacity at the start time and the target time will also differ. In this example, constant can represent the capacity difference due to the 10% difference in SBC.

[0082] The measured current acquired by the current sensor and the actual current of the battery can be considered to have a linear relationship. This can be expressed by the following formula:

[0083] A = I + z

[0084] Where A represents the current sampled by the current sensor, i.e., the measured current. I represents the actual current, and z represents the current sensor error.

[0085] Combining the two equations above, we can conclude that:

[0086] ∫Achr dt+∫A dch dt=(I slfdch +z)×Δt+constant

[0087] Among them, I slfdch +z, denoted as E, represents the measurement current error. The above formula can be expressed as:

[0088] ∫A chr dt+∫A dch dt=E×Δt+constant

[0089] Among them, ∫A chr dt represents the cumulative charging capacity obtained by integrating the sampled current over time during charging. ∫A dch dt represents the cumulative discharge capacity obtained by integrating the sampled current over time during discharge. Δt represents the cumulative duration.

[0090] According to the above formula, there is a linear relationship between the cumulative change in battery capacity and the cumulative duration and the measurement current error E. The measurement current error E can be calculated based on this relationship.

[0091] In some embodiments, all target times correspond to the same starting time. The starting time can be used as the starting point of the time axis, and the timestamp of each target time can be recorded. The timestamp can be directly used as the cumulative duration of each time. The above scheme can simplify the calculation of measurement current error.

[0092] In some implementation scenarios, there are multiple target times. Linear regression can be performed based on the cumulative duration and cumulative capacity change corresponding to multiple target times to obtain the measurement current error.

[0093] In some implementation scenarios, there are multiple target times. At least one pair of target times can be selected. For each pair of target times, the rate of change of the cumulative capacity change with the cumulative duration is calculated. Based on the rate of change corresponding to each target time, the measurement current error is determined.

[0094] The target time pair can include two arbitrary target times.

[0095] In some applications, a pair of target time points is selected, and the rate of change is calculated using the cumulative capacity change and cumulative duration corresponding to the two target time points, which serves as the measurement current error. In other applications, the rate of change for multiple target time points is calculated separately, and the measurement current error is determined based on the rate of change for each target time point. For example, the central tendency statistic of the rate of change is used as the measurement current error.

[0096] In a specific application scenario, a pre-defined time is used as the starting point and the beginning of the time axis. The cumulative capacity change over n target times is denoted as Ah. i The time of each moment is denoted as t. i The measurement current error E can be obtained using the two-point method, as shown in the following formula:

[0097]

[0098] Ah x and t x These represent the cumulative capacity change and timestamp at the first target time, respectively. The timestamp equals the cumulative duration, Ah. y and t y These represent the cumulative capacity change and the timestamp at the second target time, respectively. The timestamp is equal to the cumulative duration.

[0099] In a specific application scenario, two moments are arbitrarily selected from multiple target moments to calculate the rate of change. This process is repeated multiple times to obtain multiple rates of change, and the final measurement current error is obtained based on these multiple rates of change.

[0100] In a specific application scenario, the measurement current error E can be obtained using the linear regression method, as shown in the following formula:

[0101]

[0102] Among them, t i Ah represents the time of the i-th target moment. i This represents the cumulative capacity change at the i-th target time.

[0103] In some embodiments, the target mapping relationship represents the cumulative capacity change as equal to the sum of the first product and the remaining capacity difference, where the first product is the product of the measurement current error and the cumulative duration, and the remaining capacity difference is the difference between the remaining capacity at the start time and the target time.

[0104] In some implementation scenarios, the measurement current error can be directly calculated by substituting a set of data into the target mapping relationship. This set of data includes the cumulative duration, the corresponding cumulative capacity change, and the remaining capacity difference.

[0105] Furthermore, a set of cumulative duration, cumulative capacity change, and remaining capacity difference can be data corresponding to a certain target time.

[0106] In some implementation scenarios, a target time and a start time for consistent state of charge can be set, thus ensuring that the remaining capacity difference is zero, further simplifying the target mapping relationship. By substituting the cumulative change in capacity and cumulative duration at a given time into the target mapping relationship, the measurement current error can be calculated. For example, let the state of charge at the target time and the start time be 0.

[0107] Understandably, the corrected current can be used to calculate the battery's state of charge (SOC). During SOC calculation, current errors accumulate, and even a small current error can lead to a significant error in the SOC calculation. By pre-correcting the current and then using the corrected current to calculate the SOC, we can avoid anomalies in SOC calculations caused by accumulated measurement current errors, thus improving the accuracy of SOC calculations.

[0108] Using the above methods, a measurement current error can be obtained, which corresponds to each acquisition time. In some embodiments, all acquisition times can correspond to the same measurement current error. In some embodiments, the target time can be selected multiple times, and then the measurement error determination step can be performed to obtain multiple measurement current errors, which correspond to each acquisition time. The measurement current errors of two different acquisition times can be the same, or the measurement current errors of two different acquisition times can be different.

[0109] In a specific application scenario, AE is used as the correction current, where A represents the measured current and E represents the current error.

[0110] In a specific application scenario, the corrected current is used as input, and the state of charge is calculated using methods such as ampere-hour integration or Kalman filtering.

[0111] In some embodiments, at least one target moment is selected from the current time window. The current time window is redefined at preset intervals, and at least one target moment is reselected from the current time window. The current measurement current error is then redefined based on the at least one target moment.

[0112] The step of determining the measurement current error is repeated at preset intervals. The redefined time window can be closer to the current moment than the previous time window. This allows for the determination of the measurement current error using updated data each time. Since self-discharge current and sensor error may also change over time, this method continuously updates the measurement current error, ensuring that the current measurement current error more closely reflects the current state.

[0113] The preset duration can be set according to actual application needs. For example, the preset duration can be 1 hour or 1 day.

[0114] In a specific application scenario, the current time window is redefined every hour. The length of the time window can be set according to the actual application needs, for example, 10 days to 120 days. The target time is selected from n times within the 10 days preceding the current time.

[0115] In some embodiments, after each recalculation of the new measurement current error, the new measurement current error is used as the current measurement current error. The current measurement current error is used for correction at each acquisition time. The application scope of an updated measurement current error is all times from when that value is obtained until the next update.

[0116] In some embodiments, obtaining the cumulative capacity change of the target battery at the target time may include: obtaining the cumulative charging capacity and cumulative discharging capacity of the target battery at the target time, and determining the cumulative capacity change at the target time based on the cumulative charging capacity and cumulative discharging capacity.

[0117] In some embodiments, obtaining the cumulative charging capacity and cumulative discharging capacity of the target battery at the target time may include: obtaining the measured current between each target time and the corresponding start time, and for each target time, calculating the cumulative charging capacity and cumulative discharging capacity at the target time based on the measured current from the start time to the corresponding target time.

[0118] A positive measured current indicates that the battery is charging, while a negative measured current indicates that the battery is discharging. The cumulative charging capacity is based on the charging current, and the cumulative discharging capacity is based on the discharging current.

[0119] In some implementation scenarios, the cumulative charging capacity and cumulative discharging capacity can be calculated separately using the ampere-hour integration method. The cumulative charging capacity is positive, and the cumulative discharging capacity is negative. Adding the two together yields the change in cumulative capacity at a given moment.

[0120] In a specific application scenario, the measured current from each start time to the corresponding target time is acquired. For each target time, the cumulative charging capacity and cumulative discharging capacity at that target time are calculated based on the measured current from the corresponding start time to the target time. Based on the cumulative charging capacity and cumulative discharging capacity, the cumulative capacity change at the target time is determined. Based on the cumulative duration and cumulative capacity change at each target time, the measurement current error of the target battery is determined. The measurement current error is used to correct the measured current. The state of charge (SOC) is determined based on the corrected current.

[0121] The current measurement of the target battery can be performed by a sampling device.

[0122] In some implementation scenarios, target batteries are installed on electrical equipment, which can be used as sampling devices to measure the current of the target batteries.

[0123] In a specific application scenario, a target vehicle is equipped with a target battery, and the target vehicle can be used as a sampling device to measure the current of the target battery.

[0124] The method provided in this application can be executed by a sampling device, a processing device, or both. In some cases, the method may include sampling the target battery to obtain a measurement current, a step which can be performed by the sampling device.

[0125] It is understood that steps other than sampling can be performed by the sampling device or by the processing device. The processing device can be any device with processing capabilities that can communicate with the sampling device. For example, the processing device can be a cloud server.

[0126] In some embodiments, the sampling device acquires the measured current and calculates the cumulative capacity change corresponding to the target time, sends the cumulative capacity change at each target time to the processing device, the processing device calculates the measured current error based on the cumulative capacity change at each target time, sends the measured current error to the sampling device, and the sampling device performs the steps of current correction and state of charge determination.

[0127] Understandably, this method can be broken down into the following steps: sampling the target battery to obtain the measurement current, calculating the cumulative charging capacity and cumulative discharging capacity based on the measurement current, calculating the cumulative capacity change, calculating the measurement current error, correcting the current, and determining the state of charge. The step of sampling the target battery to obtain the measurement current is performed by the sampling device; all other steps can be performed by either the sampling device or the processing device. The device executing the previous step can pass the processing result of the previous step to the device executing the next step to implement the next data processing step.

[0128] In some implementation scenarios, all steps are performed by the sampling device. In other implementation scenarios, the step of sampling the target battery to obtain the measured current is performed by the sampling device, while other steps are performed by the processing device. In still other implementation scenarios, the step of sampling the target battery to obtain the measured current is performed by the sampling device, while other steps are performed in cooperation between the processing device and the sampling device.

[0129] The state of charge of the target battery can be provided to the sampling or processing equipment for use in other processes.

[0130] Understandably, some existing SOC correction methods rely on battery voltage. However, for some battery types with low voltage change rates, relying on battery voltage for correction is ineffective, such as lithium iron phosphate batteries and lithium manganese iron phosphate batteries. The method provided in this application first corrects for the current, without relying on voltage changes, and the accuracy of the SOC estimation is not affected by the voltage change rate.

[0131] In some embodiments, the above method for estimating the state of charge can be combined with other SOC correction schemes. For example, the SOC calculation value can be corrected based on the voltage when the battery is close to full charge / discharge, or methods such as Kalman filtering can be used in combination with battery voltage to correct the SOC.

[0132] Please see Figure 3 , Figure 3 This is a schematic diagram of a method for estimating the state of charge provided in other embodiments of this application.

[0133] The starting point of the time axis is taken as the initial time, and the sampled current at each time point is taken as the input. The input is fed into the ampere-hour integration module to calculate the cumulative capacity change at multiple time points. The cumulative capacity change at multiple time points is fed into the error calculation module. The cumulative capacity change and timestamp within a time window are selected, and the measurement current error is calculated by the two-point method or linear regression and updated by sliding window.

[0134] The measured current error and the sampled current at each time point are used as inputs to the error correction module. Based on the latest current error calculation results, the sampled current is corrected to obtain the true current. The true current is then used as input to the SOC (State of Charge) calculation module, which uses algorithms such as the ampere-hour integration method or Kalman filtering to calculate and output the SOC.

[0135] Please see Figure 4 , Figure 4 This is a schematic diagram of the framework of a state of charge estimation system provided in some embodiments of this application.

[0136] The state of charge estimation system 40 includes a sampling device 41 and a processing device 42.

[0137] Sampling device 41 is used to collect the measurement current of the target battery, and processing device 42 is used to execute the steps in the aforementioned method embodiments. Alternatively, sampling device 41 and processing device 42 may work together to execute the steps in the aforementioned method embodiments. For details, please refer to the relevant content in the aforementioned embodiments, which will not be repeated here.

[0138] The sampling device 41 and the processing device 42 can communicate with each other.

[0139] In some implementation scenarios, the target battery is mounted on the sampling device 41. In other implementation scenarios, the target battery may not be mounted on the sampling device 41; the sampling device 41 only needs to be able to measure the current of the target battery.

[0140] In a specific application scenario, the sampling device 41 can be a vehicle equipped with a battery, and the processing device 42 can be a server capable of communicating with the vehicle.

[0141] Please see Figure 5 , Figure 5 This is a schematic diagram of the framework of a state of charge estimation device provided in some embodiments of this application.

[0142] The state of charge estimation device 50 includes an acquisition module 51, a correction module 52, and a state of charge estimation module 53. The acquisition module 51 is used to acquire the measurement current error of the target battery; the correction module 52 is used to correct the measurement current of the target battery using the measurement current error to obtain the corrected current of the target battery; the state of charge estimation module 53 is used to determine the state of charge of the target battery based on the corrected current of the target battery.

[0143] In the above scheme, the measurement current error is obtained in advance, and the measurement current is corrected by using the measurement current error. The corrected current is closer to the actual output current of the battery. Based on the corrected current, the state of charge is estimated, which can improve the accuracy of the state of charge estimation.

[0144] The acquisition module 51 is used to acquire the measurement current error of the target battery, specifically including: acquiring the cumulative capacity change of the target battery at at least one target time, the cumulative capacity change being determined based on the measurement current from the start time to the corresponding target time; and determining the measurement current error of the target battery based on the cumulative duration and cumulative capacity change at at least one target time, the cumulative duration being the duration between the start time and the corresponding target time.

[0145] In the above scheme, the cumulative capacity change is obtained based on the measured current from the start time to the target time. It is related to the cumulative duration and the measurement current error. The measurement current error can be determined by using the cumulative capacity change and the cumulative duration, thereby improving the accuracy of the current characterization of the target battery.

[0146] In some embodiments, the acquisition module 51 is used to determine the measurement current error of the target battery based on the cumulative duration and cumulative capacity change corresponding to at least one target time. Specifically, it includes: calculating the measurement current error based on the target mapping relationship, the cumulative duration and cumulative capacity change corresponding to each target time; the target mapping relationship characterizes the mapping relationship between the cumulative capacity change, the cumulative duration and the measurement current error.

[0147] In the above scheme, the target mapping relationship represents the mapping relationship between the cumulative capacity change, the cumulative duration, and the measurement current error. Thus, the measurement current error can be obtained by using the target mapping relationship, the cumulative duration, and the cumulative capacity change.

[0148] In some embodiments, the target mapping relationship characterizes the cumulative capacity change as a linear change with the cumulative duration, with the measurement current error serving as the linear coefficient.

[0149] In the above scheme, the linear coefficient between the cumulative duration and the cumulative capacity change is calculated using the cumulative duration and the cumulative capacity change at at least one target time, thereby determining the measurement current error.

[0150] In some embodiments, the target mapping relationship represents the cumulative capacity change as equal to the sum of the first product and the remaining capacity difference, where the first product is the product of the measurement current error and the cumulative duration, and the remaining capacity difference is the difference between the remaining capacity at the starting time and the remaining capacity at the corresponding target time.

[0151] In the above scheme, the target mapping relationship represents that the cumulative capacity change is equal to the product of the measurement current error and the cumulative duration plus the remaining capacity difference. By combining the cumulative duration and cumulative capacity change at at least one target time, the measurement current error can be solved.

[0152] In some embodiments, there are multiple target times; the acquisition module 51 is used to calculate the measurement current error based on the target mapping relationship, the cumulative duration and cumulative capacity change corresponding to each target time, specifically including: performing linear regression based on the cumulative duration and cumulative capacity change corresponding to multiple target times to obtain the measurement current error; or, selecting at least one pair of target times from multiple target times; for each pair of target times, calculating the rate of change of cumulative capacity change with cumulative duration, and determining the measurement current error based on the rate of change corresponding to each pair of target times.

[0153] In the above scheme, when there are multiple target times, linear regression can be performed or the rate of change between two target times can be calculated to obtain the measurement current error.

[0154] In some embodiments, the acquisition module 51 may also be used to determine the current time window at preset intervals before acquiring the cumulative capacity change of the target battery at at least one target time; and select at least one target time from the current time window.

[0155] In the above scheme, the target time is reselected at preset intervals to obtain a new measurement current error, which can realize the updating of the measurement current error and improve the accuracy of the measurement current error determination.

[0156] In some embodiments, the acquisition module 51 is used to acquire the cumulative capacity change of the target battery at at least one target time, specifically including: acquiring the cumulative charging capacity and cumulative discharging capacity of the target battery at each target time; and for each target time, determining the cumulative capacity change at the target time based on the cumulative charging capacity and cumulative discharging capacity at the target time.

[0157] In the above scheme, the cumulative capacity change can be calculated based on the cumulative charging capacity and cumulative discharging capacity at the target time, and thus can be used to determine the error.

[0158] In some embodiments, the acquisition module 51 is used to acquire the cumulative charging capacity and cumulative discharging capacity of the target battery at each target time, specifically including: acquiring the measured current between each target time and the corresponding start time; for each target time, calculating the cumulative charging capacity and cumulative discharging capacity at the target time based on the measured current between the target time and the corresponding start time.

[0159] In the above scheme, the cumulative charging capacity and cumulative discharging capacity can be calculated by measuring the current, which can then be used to determine the error.

[0160] Please see Figure 6 , Figure 6 This is a schematic diagram of the framework of an electronic device provided in some embodiments of this application.

[0161] Electronic device 60 includes memory 61 and processor 62. Processor 62 is used to execute program instructions stored in memory 61 to implement any of the above-described methods for estimating the state of charge. In a specific implementation scenario, electronic device 60 may include, but is not limited to: computer equipment, electrical equipment, microcomputer, desktop computer, server. In addition, electronic device 60 may also include mobile devices such as laptops and tablets, which are not limited here.

[0162] Specifically, processor 62 controls itself and memory 61 to implement any of the aforementioned methods for estimating the state of charge. Processor 62 can also be referred to as a CPU (Central Processing Unit). Processor 62 may be an integrated circuit chip with signal processing capabilities. Processor 62 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. A general-purpose processor can be a microprocessor or any conventional processor. Furthermore, processor 62 can be implemented using integrated circuit chips.

[0163] Please see Figure 7 , Figure 7 This is a schematic diagram of the framework of a computer-readable storage medium provided in some embodiments of this application.

[0164] The computer-readable storage medium 70 stores program instructions 71 that can be executed by a processor. When the program instructions 71 are executed by the processor, they are used to implement the estimation method for any of the above-mentioned states of charge.

[0165] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0166] In the several embodiments provided in this application, it should be understood that the disclosed methods and apparatus can be implemented in other ways. For example, the apparatus implementations described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, units or components may be combined or integrated into another subsystem, or some features may be ignored or not executed. Furthermore, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms.

[0167] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for estimating the state of charge, characterized in that, The method includes: Obtain the measurement current error of the target battery; The measured current of the target battery is corrected using the measured current error to obtain the corrected current of the target battery; The state of charge of the target battery is determined based on the corrected current of the target battery.

2. The method according to claim 1, characterized in that, The measurement current error of the target battery includes: The cumulative capacity change of the target battery at at least one target time is obtained, and the cumulative capacity change is determined based on the measured current from the start time to the corresponding target time. Based on the cumulative duration corresponding to the at least one target time and the cumulative capacity change, the measurement current error of the target battery is determined, and the cumulative duration is the duration of the interval between the start time and the corresponding target time.

3. The method according to claim 2, characterized in that, The determination of the measurement current error of the target battery based on the cumulative duration corresponding to the at least one target time and the cumulative capacity change includes: The measurement current error is calculated based on the target mapping relationship, the cumulative duration and cumulative capacity change corresponding to each target time; the target mapping relationship characterizes the mapping relationship between the cumulative capacity change, the cumulative duration and the measurement current error.

4. The method according to claim 3, characterized in that, The target mapping relationship represents the linear change of the cumulative capacity with the cumulative duration, and the measurement current error is used as a linear coefficient.

5. The method according to claim 4, characterized in that, The target mapping relationship indicates that the cumulative capacity change is equal to the sum of the first product and the remaining capacity difference, where the first product is the product of the measurement current error and the cumulative duration, and the remaining capacity difference is the difference between the remaining capacity at the starting time and the remaining capacity at the corresponding target time.

6. The method according to claim 4 or 5, characterized in that, The number of target times is multiple; the measurement current error calculated based on the target mapping relationship, the cumulative duration and cumulative capacity change corresponding to each target time includes: The measurement current error is obtained by performing linear regression based on the cumulative duration and cumulative capacity change corresponding to multiple target times. Alternatively, at least one pair of target times is selected from the plurality of target times; for each pair of target times, the rate of change of the cumulative capacity change with the cumulative duration is calculated, and the measurement current error is determined based on the rate of change corresponding to each pair of target times.

7. The method according to any one of claims 2 to 6, characterized in that, Before obtaining the cumulative capacity change of the target battery at at least one target time, the method further includes: The current time window is determined at each preset interval; Select the at least one target time from the current time window.

8. The method according to any one of claims 2 to 7, characterized in that, The step of obtaining the cumulative capacity change of the target battery at at least one target time includes: Obtain the cumulative charging capacity and cumulative discharging capacity of the target battery at each of the target times; For each target time, the cumulative capacity change corresponding to the target time is determined based on the cumulative charging capacity and cumulative discharging capacity corresponding to the target time.

9. The method according to claim 8, characterized in that, The step of obtaining the cumulative charging capacity and cumulative discharging capacity of the target battery at each of the target times includes: The measured current between each target time and the corresponding start time is obtained respectively; For each target time, the cumulative charging capacity and cumulative discharging capacity at the target time are calculated based on the measured current between the target time and the corresponding start time.

10. A system for estimating the state of charge, characterized in that, The system includes: A sampling device and a processing device, wherein the sampling device is used to collect a measurement current of a target battery, and the processing device performs the method as described in any one of claims 1 to 9, or the sampling device and the processing device cooperate to perform the method as described in any one of claims 1 to 9.

11. A device for estimating the state of charge, characterized in that, include: The acquisition module is used to acquire the measurement current error of the target battery; A correction module is used to correct the measured current of the target battery using the measurement current error, so as to obtain the corrected current of the target battery; The state of charge estimation module is used to determine the state of charge of the target battery based on the corrected current of the target battery.

12. An electronic device, characterized in that, The method includes a memory and a processor, wherein the memory stores program instructions that, when executed by the processor, are used to perform the method described in any one of claims 1 to 9.

13. A computer-readable storage medium having program instructions stored thereon, characterized in that, When the program instructions are executed by the processor, they implement the method described in any one of claims 1 to 9.

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