Battery SOC calculation method and device, battery management system and computer readable storage medium

Abstract

The invention provides a battery SOC calculation method and device, a battery management system and a computer readable storage medium, and the calculation method comprises the steps: calculating an initial electric quantity based on an initial voltage, charging and discharging parameters and a cell OCV-SOC curve model; calculating an open-circuit voltage at the current moment based on the voltage, the current and the fusion impedance at the current moment; based on the electric quantity variable quantity at the current moment, calculating a circuit accumulated measurement deviation and an effective capacity deviation of the battery cell, and calculating a calibration electric quantity at the current moment; and predicting the actual electric quantity at the current moment based on the target electric quantity and the charging and discharging parameters, secondarily calibrating the actual electric quantity at the current moment by combining the calibration electric quantity, and realizing electric quantity and state synchronization. According to the battery SOC calculation method, accurate and real-time calculation and updating of the battery SOC are achieved by fusing the battery model, the operation parameters and the charging and discharging parameters, the method has the advantages of being high in precision, low in power consumption, real-time and reliable, SOC changes can be rapidly responded in the charging and discharging process, and the applicability is wide.

Description

Technical Field

[0001] The present invention relates to the field of battery management technology, and specifically but not limited to a battery SOC calculation method, device, battery management system, and computer-readable storage medium. Background Art

[0002] In recent years, with the rapid development of smart devices and IoT terminals, batteries, as their core energy supply unit, have attracted widespread attention, and their performance and condition monitoring technologies have received widespread attention. Among them, the battery's State of Charge (SOC), a key indicator of remaining battery power, directly affects the user's perception of device endurance and the product experience. Therefore, how to efficiently and accurately measure battery SOC has become a key technical issue in enhancing product competitiveness.

[0003] In response to the needs of SOC detection, the main fuel gauge chip solutions currently used in the industry include the open circuit voltage method, the dynamic voltage method, and the Coulomb integration method. Each method is based on different technical principles and has its own characteristics in terms of accuracy, response speed, and applicable scenarios, but it also has corresponding technical limitations. (1) The open circuit voltage method measures the open circuit voltage (OCV) of the battery cell and estimates the remaining power by combining the mapping relationship between the internal ion concentration of the cell and the SOC. Its advantage is that it can achieve high measurement accuracy under static conditions. However, the open circuit voltage method requires the cell to be in a static state for a long time to achieve internal electrochemical balance, resulting in its inability to respond in real time in dynamic charging and discharging scenarios, making it difficult to meet the application requirements of frequent charging and discharging or severe load fluctuations. (2) The dynamic voltage method estimates the SOC by monitoring the dynamic change trend of the battery voltage and combining the load state. Its advantage is that it has low requirements for processor computing power and is suitable for resource-constrained embedded systems. However, due to the nonlinear relationship between the voltage and power of the battery cell, especially under low power or high load conditions, the voltage fluctuates significantly, resulting in a significant decrease in the accuracy of SOC estimation, making it difficult to meet the requirements of high-precision application scenarios. (3) The Coulomb integration method calculates SOC by accumulating the charge capacity changes during the charging and discharging process in real time. It has the advantages of simple principle and easy implementation. However, in practical applications, the coulomb meter is limited by the sampling error of the hardware circuit. Long-term operation will lead to an increase in the charge accumulation error. In addition, the effective capacity of the lithium battery fluctuates with temperature, further introducing calculation deviations. It is necessary to rely on additional temperature compensation or periodic calibration to maintain accuracy.

[0004] In view of this, it is necessary to provide a new method to solve at least part of the above problems. Summary of the Invention

[0005] In response to at least one or more problems in the background technology, the present invention proposes a battery SOC calculation method, device, battery management system and computer-readable storage medium, which achieve high-precision, low-power and real-time reliable SOC calculation by integrating multi-parameter detection and correction.

[0006] According to one aspect of the present invention, a battery SOC calculation method includes:

[0007] Calculate the initial capacity of the battery based on the initial voltage of the battery, the charge and discharge parameters of the battery, and the OCV-SOC curve model of the battery cell;

[0008] Calculate the open circuit voltage of the battery at the current moment based on the voltage, current and fusion impedance of the battery at the current moment;

[0009] Based on the current battery charge change, the circuit's cumulative measurement deviation and the battery cell's effective capacity deviation are calculated, and the actual battery charge at the current moment is calibrated.

[0010] The actual power of the battery at the current moment is predicted based on the target power and the battery's charge and discharge parameters. Combined with the actual power of the battery at the current moment obtained by the calibration, the actual power of the battery at the current moment is recalibrated to synchronize the actual power with the full charge or full discharge state.

[0011] Optionally, the charge and discharge parameters of the battery include charge cut-off current and voltage, and discharge cut-off current and voltage.

[0012] Optionally, the initial charge of the battery is:

[0013]

[0014] Among them, SOC0 represents the initial charge of the battery, f() represents the OCV-SOC curve model function of the battery cell, V init Indicates the initial voltage of the battery, V eoc Indicates the charging cut-off voltage, V eod Indicates the discharge cut-off voltage.

[0015] Optionally, calculating the open circuit voltage of the battery at the current moment includes:

[0016] Calculate the current battery fusion impedance based on the current battery cell temperature and power level, as well as the voltage and current changes over a short period of time;

[0017] The voltage and current of the battery at the current moment are obtained, and the open circuit voltage of the battery at the current moment is calculated in combination with the fusion impedance.

[0018] Optionally, the open circuit voltage of the battery at the current moment is:

[0019] OCV t =V t +Z t *I t

[0020]

[0021] Among them, OCV t represents the open circuit voltage of the battery at the current moment, t represents the current moment, V t Indicates the battery voltage at the current moment, I t Indicates the battery current at the current moment, Z t represents the fusion impedance of the battery at the current moment, g() represents the arithmetic mean function or weighted average function, ΔV represents the voltage change of the battery in a short time, ΔI represents the current change of the battery in a short time, lut() represents the matching model function of power, temperature and impedance, T t Indicates the temperature of the battery cell at the current moment, SOC t-1 Indicates the battery power at the last moment.

[0022] Optionally, calibrating the actual battery power at the current moment includes:

[0023] Calculate the battery charge change at the current moment based on the battery charge change at the current moment and the battery's full charge capacity;

[0024] Calculate the cumulative measurement deviation of the circuit and the effective capacity deviation of the battery cell, and based on the change in battery power at the current moment, correct the change in battery power at the current moment to obtain a corrected battery power at the current moment;

[0025] Based on the battery power at the previous moment and the actual battery power correction amount at the current moment, the actual battery power at the current moment is calibrated to obtain the calibrated battery power at the current moment.

[0026] Optionally, the battery charge change at the current moment is obtained by integrating the current through a coulomb meter.

[0027] Optionally, the battery charge change at the current moment is:

[0028]

[0029] Among them, ΔSOC t Indicates the change in battery power at the current moment, ΔCC t It indicates the current integral difference of the battery at the current moment, and FCC indicates the full charge capacity of the battery.

[0030] Optionally, the full charge capacity of the battery is the rated capacity of the battery cell, that is,

[0031] FCC=Q design

[0032] Among them, FCC represents the full charge capacity of the battery, Q design Indicates the rated capacity of the battery cell.

[0033] Optionally, calculating the cumulative measurement deviation includes:

[0034] Calculate the relative power of the battery at the current moment based on the open circuit voltage of the battery at the current moment and the OCV-SOC curve model of the battery cell;

[0035] Based on the relative power level of the battery and the actual power level of the battery at the current moment, a cumulative measurement deviation is calculated.

[0036] Optionally, the cumulative measurement deviation is:

[0037]

[0038] Among them, RSOC t Indicates the relative power of the battery at the current moment, f() represents the OCV-SOC curve model function of the battery cell, OCV t Indicates the open circuit voltage of the battery at the current moment, V eoc Indicates the charging cut-off voltage, V eod Indicates the discharge cut-off voltage, Indicates the cumulative measurement deviation, h1() represents the first deviation calculation function, which is used to calculate the cumulative measurement deviation between the current battery power and the relative power, SOC t Indicates the current battery level.

[0039] Optionally, calculating the effective capacity deviation includes:

[0040] The temperature of the battery cell at the current moment, the power level of the battery at the current moment, and the voltage change of the battery at the current moment are obtained, and the effective capacity deviation is calculated.

[0041] Optionally, the effective capacity deviation is:

[0042] δ=h2(SOC t ,T t ,ΔV t )

[0043] Among them, δ represents the effective capacity deviation, h2() represents the second deviation calculation function, which is used to calculate the effective capacity deviation under the conditions of battery power, cell temperature and voltage change at the current moment, SOC t Indicates the battery power at the current moment, T t Indicates the temperature of the battery cell at the current moment, ΔV tIndicates the battery voltage change at the current moment.

[0044] Optionally, the corrected battery capacity at the current moment is:

[0045]

[0046] Among them, Δfix_SOC t Indicates the corrected battery capacity at the current moment, ΔSOC t Indicates the change in battery power at the current moment. represents the cumulative measurement deviation, and δ represents the effective capacity deviation.

[0047] Optionally, the calibrated battery power at the current moment is:

[0048] SOC t_c =SOC t-1 +Δfix_SOC t

[0049] Among them, SOC t_c Indicates the current battery calibration capacity, SOC t-1 Indicates the battery power at the last moment, Δfix_SOC t Indicates the corrected battery capacity at the current moment.

[0050] Optionally, the secondary calibration of the actual battery power at the current moment includes:

[0051] Based on the current charge level, current or voltage, and the target full charge level and charge cutoff current, or the target full discharge level and discharge cutoff voltage, predict the battery charge change at the current moment.

[0052] Predicting the actual battery power at the current moment based on the predicted battery power change at the current moment and the battery power at the previous moment;

[0053] Based on the predicted actual power of the battery at the current moment and the calibrated actual power of the battery at the current moment, the actual power of the battery at the current moment is calibrated twice so that it is synchronized to 100% when the current at the current moment reaches the charging cut-off current, or synchronized to 0% when the voltage at the current moment reaches the discharging cut-off voltage.

[0054] Optionally, the predicted battery charge change at the current moment is:

[0055]

[0056] Among them, ΔSOC predict Indicates the predicted battery charge change at the current moment, SOC 100％ Indicates the target full charge capacity, SOCt Indicates the current battery power, I eoc Indicates the target full charge current, I t represents the current battery charging current, and ΔI represents the current battery current change; or

[0057]

[0058] Among them, SOC 0％ Indicates the target full discharge capacity, V t Indicates the current battery voltage, V eod represents the target full-discharge voltage, and ΔV represents the battery voltage change at the current moment.

[0059] Optionally, the actual battery power at the current moment of the secondary calibration is:

[0060] SOC t_finnal =F(SOC t_c ,SOC t_p )

[0061] Among them, SOC t_finnal Indicates the secondary calibration capacity of the battery at the current moment, F() represents the fusion filter function, SOC t_c Indicates the current battery calibration capacity, SOC t_p Indicates the estimated battery capacity at the current moment.

[0062] Optionally, the fusion filter function F() is an arithmetic average filter function, a weighted average filter function, an inertial filter function, a Kalman filter function or an adaptive filter function.

[0063] According to another aspect of the present invention, a battery SOC calculation device includes:

[0064] Acquisition module, used to obtain battery charge and discharge parameters and operating parameters;

[0065] A first calculation module, used to calculate the initial power of the battery;

[0066] The second calculation module is used to calculate the open circuit voltage of the battery at the current moment;

[0067] a calibration module, configured to calculate a calibration capacity of the battery at a current moment based on the open circuit compensation voltage;

[0068] The secondary calibration module is used to predict the change in battery power at the current moment and calculate the actual battery power at the current moment based on the calibration power.

[0069] According to another aspect of the present invention, a battery management system includes a processor, a memory, and a computer program stored in the memory and running on the processor, wherein the processor implements any of the steps of the above-mentioned battery SOC calculation method when running the computer program.

[0070] According to another aspect of the present invention, a computer-readable storage medium stores a computer program, which implements the steps of any of the above-mentioned battery SOC calculation methods when executed by a processor.

[0071] The battery SOC calculation method and system proposed in the present invention realize battery SOC calculation and update by integrating battery model parameters, charge and discharge parameters, battery state parameters, and detection and correction of operating parameters. It has the advantages of high accuracy, low power consumption, and real-time reliability. It can quickly respond to SOC changes during the charge and discharge process and has wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] The accompanying drawings are used to provide a further understanding of the present invention and, together with the description, to explain the embodiments of the present invention, but do not constitute a limitation of the present invention. In the accompanying drawings:

[0073] Figure 1 A flow chart of a battery SOC calculation method according to an embodiment of the present invention is shown;

[0074] Figure 2 A flowchart of calculating the initial battery capacity according to an embodiment of the present invention is shown;

[0075] Figure 3 shows a flow chart for calculating open circuit voltage according to an embodiment of the present invention;

[0076] Figure 4 A flow chart showing the calibration of electrical quantity according to an embodiment of the present invention is shown;

[0077] Figure 5 A flow chart showing the calibration of electrical quantity according to another embodiment of the present invention is shown;

[0078] Figure 6 A flow chart of secondary calibration of electrical quantity according to an embodiment of the present invention is shown;

[0079] Figure 7 A schematic diagram showing changes in battery voltage and relative charge during a complete charging process according to an embodiment of the present invention is shown;

[0080] Figure 8 A schematic diagram showing changes in battery voltage and relative charge during a complete discharge process according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0081] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0082] The description in this section focuses on a few typical embodiments only, and the present invention is not limited to the scope of the embodiments described. Combinations of different embodiments, replacement of certain technical features in different embodiments, and replacement of certain technical features in the embodiments with the same or similar prior art methods are also within the scope of the present invention.

[0083] "Coupled" or "connected" in this specification encompasses both direct and indirect connections. An indirect connection is a connection through an intermediate medium, such as a connection through an electrically conductive medium like a conductor, which may contain parasitic inductance or capacitance, or a connection through an intermediate circuit or component as described in the embodiments of this specification. An indirect connection may also include a connection through other active or passive devices that achieve the same or similar functions, such as a connection through circuits or components such as switches, signal amplifiers, and follower circuits. "Multiple" or "many" refers to two or more.

[0084] A battery SOC calculation method, such as Figure 1 Shown, including:

[0085] Step 1: Calculate the initial capacity of the battery based on the initial voltage of the battery, charge and discharge parameters, and the OCV-SOC curve model of the battery cell.

[0086] In one embodiment, Figure 2 As shown, measure the initial voltage V of the battery init The initial charge of the battery is determined by combining the charge and discharge parameters of the battery with the open circuit voltage-capacity (OCV-SOC) curve model of the battery cell.

[0087] Among them, the charging and discharging parameters of the battery system include the charging cut-off voltage V eoc and discharge cut-off voltage V eod , charging cut-off voltage V eoc and discharge cut-off voltage V eod It depends on the working conditions of the entire battery system, which is clear in advance.

[0088]

[0089] Wherein, SOC0 represents the initial charge of the battery system, and f() represents the OCV-SOC curve model function.

[0090] Step S02: Estimate the open circuit voltage (OCV) of the battery at the current moment based on the current power level. t.

[0091] In one embodiment, Figure 3 As shown, based on the storage containing temperature T t , SOC t-1 The impedance Z1 and the impedance Z2 calculated based on the voltage change ΔV and current change ΔI of the battery in a short period of time are combined to obtain the impedance compensation value Z t and open circuit voltage:

[0092] Z1=lut(SOC t-1 ,T t )

[0093]

[0094] Z t =g(Z1,Z2)

[0095] OCV t =V t +Z t *I t

[0096] Among them, Z1 represents the model impedance of the current charge and temperature. The impedance values ​​at different temperatures and different charges can be obtained by fitting the battery parameters or by performing offline battery testing, and stored in the flash of the fuel gauge in the form of a parameter database. Z2 represents the estimated dynamic impedance of the battery. t Indicates the current battery fusion impedance. OCV t Represents the estimated open-circuit voltage of the battery at the current moment. lut() represents the matching model function for charge, temperature, and impedance. This function can be obtained through electrochemical analysis of the battery cell, such as by fitting the impedance distribution characteristics of a complete discharge test and recording the depth of discharge at different temperatures. g() represents the fusion function of the model impedance Z1 and the dynamic impedance Z2. g() can be an arithmetic average function or a weighted average function, depending on the actual characteristics of the battery system.

[0097] Step S03: iteratively updating the power level based on the full charge capacity of the battery.

[0098] In one embodiment, Figure 4 As shown, the change in battery charge can be determined by measurement.

[0099] In a specific embodiment, the charge change can be obtained by counting the current integral of the battery by a coulomb meter, such as obtaining the current integral difference ΔCC between the current time t and the previous time t-1 by a coulomb meter. t . Change the charge to ΔCC tThe ratio of the full charge capacity FCC of the battery is used as the current system power change ΔSOC t The full charge capacity FCC of the battery can use the rated capacity Q of the battery cell. design As a reference substitute. The specific calculation formula is as follows:

[0100]

[0101] FCC=Q design

[0102] Among them, ΔCC t Indicates the current integral difference between the current time t and the previous time t-1, FCC represents the full charge capacity of the battery, ΔSOC t Indicates the change in power between the current time t and the previous time t-1, Q design Indicates the rated capacity of the battery.

[0103] The above-mentioned measurement-based power change ΔCC t and battery cell rated capacity Q design Determine the current charge change ΔSOC t , the amount of charge change ΔSOC t There is a cumulative measurement deviation in the circuit system The deviation from the effective capacity of the battery is δ. The circuit system generally refers to the hardware circuit, including the battery pack circuit board, hardware motherboard and other working circuits, which will accumulate the measurement deviation. Quantified as charge change ΔCC t The error scale factor of the effective capacity deviation δ is quantified as the error scale factor of the full charge capacity FCC.

[0104] In a specific embodiment, Figure 5 As shown, S0301, the cumulative measurement deviation of the circuit system The correction can be made by introducing synchronous measurement of relevant state quantities. Preferably, the relative power can be calculated based on the currently estimated OCV voltage and the OCV-SOC curve of the battery cell.

[0105]

[0106] Among them, RSOC t Indicates the relative power at the current moment, OCV t Indicates the estimated open circuit voltage value at the current moment, V eod Indicates the battery's full discharge cut-off voltage, V eoc represents the full charge cut-off voltage of the battery, and f() represents the OCV-SOC curve model function. Indicates the cumulative measurement deviation of the circuit system, h1() represents the deviation factor function of the current battery power and the relative power. h() can be a segmented weighted division, that is: for SOC t Segmentation is performed, and different weights w are configured according to different segmentation intervals, and w*RSOC is used to calculate the weights w*RSOC. t / SOC t Obtain the cumulative measurement deviation of different segmented intervals.

[0107] S0302: The effective capacity deviation δ of a battery cell is closely related to the cell's electrochemical characteristics. In high and low temperature environments, the electrochemical reactions of lithium batteries are inconsistent, resulting in a deviation between the actual full charge capacity (FCC) and the rated capacity. The effective capacity deviation can be estimated based on the current cell temperature, battery charge, and voltage changes.

[0108] δ=h2(SOC t ,T t ,ΔV t )

[0109] δ represents the effective capacity deviation of the battery, and h2() represents the update rate function of the battery capacity under the current battery capacity, current temperature and changing voltage. t Indicates the current battery temperature, ΔV t Indicates the voltage change between the current time t and the previous time t-1.

[0110] By measuring the cumulative deviation of the circuit system The estimation of the effective capacity deviation δ of the battery cell is used to further calibrate the actual power change.

[0111]

[0112] Where ΔSOC t Indicates the amount of charge change calculated based on the current integral change between the current time t and the previous time t-1, Δfix_SOC t Indicates the actual power correction amount between the current time t and the previous time t-1.

[0113] Based on the battery capacity SOC determined at the last moment t-1 and the actual power correction value Δfix_SOC at the current moment t , calibrate and update to get the actual power calibration value SOC at the current moment t_c :

[0114] SOC t_c =SOC t-1 +Δfix_SOC t

[0115] Among them, SOC t_cIndicates the actual battery charge calibration value at the current moment, SOC t-1 Indicates the battery capacity at the last moment, Δfix_SOC t Indicates the corrected rate of change of battery charge at the current moment.

[0116] Step S04 , controlling the full charge (100%) and full discharge (0%) of the battery under the charging end condition and the discharging end condition based on the charging and discharging parameters.

[0117] In one embodiment, Figure 6 As shown, the battery system's end-of-charge conditions are related to the system's charge management. Generally, based on application requirements, the fuel gauge chip must ensure that the SOC reaches 100% when the battery voltage reaches the CV voltage and the current is less than the EOC (End of Charge Current). The deviation between the charging current at 100% SOC and the system's set EOC current is a key indicator of the fuel gauge's charging algorithm.

[0118] Based on the set target full charge capacity SOC = 100% and the target full charge current EOC, the current charge change is predicted and tracked, and the current battery system charge SOC is adjusted and updated. In a specific embodiment, the change in current can be calculated to predict and update the change in charge ΔSOC at the current charging state. predict1 .

[0119] The changes in battery voltage and relative charge during a complete charging process are as follows: Figure 7 As shown, for the final system power SOC t_finnal1 This can be achieved by making a secondary adjustment to the result of step S03. The adjustment function can be implemented using a filter tracking algorithm. Depending on the actual application characteristics of the battery system, there are different implementation methods for the filter algorithm, including but not limited to arithmetic average filtering, weighted average filtering, inertial filtering, Kalman filtering, adaptive filtering, etc.

[0120]

[0121] SOC t_p1 =SOC t-1 +ΔSOC predict1

[0122] SOC t_finnal1 =f(SOC t_c ,SOC t_p1 )

[0123] Where ΔSOC predict1 Indicates the predicted change in power between the current time t and the previous time t-1, SOC 100％Indicates the fully charged battery capacity, SOC t Indicates the current battery level, I eoc Indicates the charging current when fully charged, I t Indicates the current charging current, and ΔI indicates the current change between the current time t and the previous time t-1. t_p1 Indicates the predicted power at the current moment, SOC t_c Indicates the current calibration power, SOC t_finnal1 The function f() represents the fusion filter function of the current corrected battery capacity and the predicted battery capacity.

[0124] S0402: The battery system's end-of-discharge condition is dependent on the system's application circuitry. Generally, based on application requirements, the fuel gauge chip must update the SOC to 0% before the battery voltage drops to the EOD (End of Discharge) voltage. The deviation between the battery voltage at 0% SOC and the system's set EOD voltage is a key indicator of the fuel gauge's discharge algorithm.

[0125] Based on the set target full discharge capacity SOC = 0% and the target cut-off voltage EOD, the current power change is predicted and tracked, and the current battery system power SOC is adjusted and updated. In a specific embodiment, the change in voltage can be calculated to predict and update the change in power ΔSOC in the current discharge state. predict2 .

[0126] The changes in battery voltage and relative charge during a complete charging process are as follows: Figure 8 As shown, for the final system power SOC t_finnal2 This can be achieved by making a secondary adjustment to the result of step S03. The adjustment function can be implemented using a filter tracking algorithm. Depending on the actual application characteristics of the battery system, there are different implementation methods for the filter algorithm, including but not limited to arithmetic average filtering, weighted average filtering, inertial filtering, Kalman filtering, adaptive filtering, etc.

[0127]

[0128] SOC t_p2 =SOC t-1 +ΔSOC predict2

[0129] SOC t_finnal2 =f(SOC t_c ,SOC t_p2 )

[0130] Where ΔSOC predict2Indicates the predicted change in power between the current time t and the previous time t-1, SOC 0％ Indicates the full battery capacity, SOC t Indicates the current battery power, V eod Indicates the cut-off voltage when fully discharged, V t Represents the battery voltage at the current moment, and ΔV represents the battery voltage change between the current moment t and the previous moment t-1. t_p2 Indicates the predicted power at the current moment, SOC t_c Indicates the current calibration power, SOC t_finnal2 The function f() represents the fusion filter function of the current corrected battery capacity and the predicted battery capacity.

[0131] The battery SOC calculation method provided by the present invention is as follows: Figure 1 As shown, the system power level at different times is calculated and updated through initialization and subsequent iterations. It should be noted that, although not directly marked in the figure, steps S02 to S04 in the illustrated method can be repeatedly executed until the final termination condition is met, such as completing a complete battery system charge or discharge cycle.

[0132] A battery SOC calculation device can be used to implement the above-mentioned battery SOC calculation method. The device includes an acquisition module, a first calculation module, a second calculation module, a calibration module and a secondary calibration module, wherein: the acquisition module is used to obtain the charging and discharging parameters and operating parameters of the battery; the first calculation module is used to calculate the initial power of the battery; the second calculation module is used to calculate the open circuit voltage of the battery at the current moment; the calibration module is used to calculate the calibrated power of the battery at the current moment based on the open circuit compensation voltage; and the secondary calibration module is used to predict the change in the battery power at the current moment and calculate the actual power of the battery at the current moment based on the calibrated power.

[0133] A battery management system includes a processor, a memory, and a computer program stored in the memory and running on the processor. When the processor runs the computer program, the steps of the battery SOC calculation method are implemented.

[0134] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the above-mentioned battery SOC calculation method.

[0135] It should be noted that although the method uses different processes of steps S03 and S04 in the iteration of updating the power, it is necessary to make it clear that the relevant steps and processes can be combined with each other or operated independently. That is, in the power update, step S03 can be used to update the battery system power at the current time by obtaining the change of the power and the power at the last time state; step S04 can be used to predict the current battery system by predicting the power of the entire charging and discharging target and the end condition; steps S03 and S04 can be used at the same time to calculate and update the battery system power SOC.

[0136] Those skilled in the art should know that "high level" and "low level", "set" and "reset", "and gate" and "or gate", "in-phase input end" and "inverted input end" and other logic controls in the logical control involved in the description or drawings can be exchanged or changed, and the same functions or purposes as the above embodiments can be achieved by adjusting the subsequent logical control.

[0137] The description and application of the present application herein are illustrative, and are not intended to limit the scope of the present application to the above embodiments. The effects or advantages related descriptions involved in the description may not be embodied in actual experimental examples due to the uncertainty of specific conditions or other factors, and the effects or advantages related descriptions are not used to limit the scope of the application. Variations and changes of the disclosed embodiments are possible, and the alternatives and equivalent components of the embodiments are known to those skilled in the art. It should be clear to those skilled in the art that the present application can be realized in other forms, structures, arrangements, proportions, and with other components, materials and parts without departing from the spirit or essential characteristics of the present application. Other variations and changes of the disclosed embodiments can be made without departing from the scope and spirit of the present application.

Claims

1. A battery SOC calculation method, characterized in that: include: Calculate the initial capacity of the battery based on the initial voltage of the battery, the charge and discharge parameters of the battery, and the OCV-SOC curve model of the battery cell; Calculate the open circuit voltage of the battery at the current moment based on the voltage, current and fusion impedance of the battery at the current moment; Based on the current battery charge change, the circuit's cumulative measurement deviation and the battery cell's effective capacity deviation are calculated, and the actual battery charge at the current moment is calibrated. The actual power of the battery at the current moment is predicted based on the target power and the battery's charge and discharge parameters. Combined with the actual power of the battery at the current moment obtained by the calibration, the actual power of the battery at the current moment is recalibrated to synchronize the actual power with the full charge or full discharge state.

2. The battery SOC calculation method according to claim 1, characterized in that: The charge and discharge parameters of the battery include charge cut-off current and voltage, and discharge cut-off current and voltage.

3. The battery SOC calculation method according to claim 1 or 2, characterized in that: The initial charge of the battery is: Among them, SOC0 represents the initial charge of the battery, f() represents the OCV-SOC curve model function of the battery cell, V init Indicates the initial voltage of the battery, V eoc Indicates the charging cut-off voltage, V eod Indicates the discharge cut-off voltage.

4. The battery SOC calculation method according to claim 1, characterized in that: Calculating the open circuit voltage of the battery at the current moment includes: Calculate the current battery fusion impedance based on the current battery cell temperature and power level, as well as the voltage and current changes over a short period of time; The voltage and current of the battery at the current moment are obtained, and the open circuit voltage of the battery at the current moment is calculated in combination with the fusion impedance.

5. The battery SOC calculation method according to claim 1 or 4, characterized in that: The open circuit voltage of the battery at the current moment is: OCV t =V t +Z t *I t Among them, OCV t represents the open circuit voltage of the battery at the current moment, t represents the current moment, V t Indicates the battery voltage at the current moment, I t Indicates the battery current at the current moment, Z t represents the fusion impedance of the battery at the current moment, g() represents the arithmetic mean function or weighted average function, ΔV represents the voltage change of the battery in a short time, ΔI represents the current change of the battery in a short time, lut() represents the matching model function of power, temperature and impedance, T t Indicates the temperature of the battery cell at the current moment, SOC t-1 Indicates the battery power at the last moment.

6. The battery SOC calculation method according to claim 1, characterized in that: The calibrating of the actual battery capacity at the current moment includes: Calculate the battery charge change at the current moment based on the battery charge change at the current moment and the battery's full charge capacity; Calculate the cumulative measurement deviation of the circuit and the effective capacity deviation of the battery cell, and based on the change in battery power at the current moment, correct the change in battery power at the current moment to obtain a corrected battery power at the current moment; Based on the battery power at the previous moment and the actual battery power correction amount at the current moment, the actual battery power at the current moment is calibrated to obtain the calibrated battery power at the current moment.

7. The battery SOC calculation method according to claim 6, characterized in that: The battery charge change at the current moment is obtained by integrating the current through a coulomb meter.

8. The battery SOC calculation method according to claim 6, characterized in that: The battery charge change at the current moment is: Among them, ΔSOC t Indicates the change in battery power at the current moment, ΔCC t It indicates the current integral difference of the battery at the current moment, and FCC indicates the full charge capacity of the battery.

9. The battery SOC calculation method according to claim 6 or 8, characterized in that: The full charge capacity of the battery is the rated capacity of the battery cell, that is, FCC=Q design Among them, FCC represents the full charge capacity of the battery, Q design Indicates the rated capacity of the battery cell.

10. The battery SOC calculation method according to claim 6, characterized in that: The calculation of the cumulative measurement deviation includes: Calculate the relative power of the battery at the current moment based on the open circuit voltage of the battery at the current moment and the OCV-SOC curve model of the battery cell; Based on the relative power level of the battery and the actual power level of the battery at the current moment, a cumulative measurement deviation is calculated.

11. The battery SOC calculation method according to claim 6 or 10, characterized in that: The cumulative measurement deviation is: Among them, RSOC t Indicates the relative power of the battery at the current moment, f() represents the OCV-SOC curve model function of the battery cell, OCV t Indicates the open circuit voltage of the battery at the current moment, V eoc Indicates the charging cut-off voltage, V eod Indicates the discharge cut-off voltage, Indicates the cumulative measurement deviation, h1() represents the first deviation calculation function, which is used to calculate the cumulative measurement deviation between the current battery power and the relative power, SOC t Indicates the current battery level.

12. The battery SOC calculation method according to claim 6, characterized in that: The calculation of the effective capacity deviation includes: The temperature of the battery cell at the current moment, the power level of the battery at the current moment, and the voltage change of the battery at the current moment are obtained, and the effective capacity deviation is calculated.

13. The battery SOC calculation method according to claim 6 or 12, characterized in that: The effective capacity deviation is: δ=h2(SOC t ,T t ,ΔV t ) Among them, δ represents the effective capacity deviation, h2() represents the second deviation calculation function, which is used to calculate the effective capacity deviation under the conditions of battery power, cell temperature and voltage change at the current moment, SOC t Indicates the battery power at the current moment, T t Indicates the temperature of the battery cell at the current moment, ΔV t Indicates the battery voltage change at the current moment.

14. The battery SOC calculation method according to claim 6, characterized in that: The corrected battery capacity at the current moment is: Among them, Δfix_SOC t Indicates the corrected battery capacity at the current moment, ΔSOC t Indicates the change in battery power at the current moment. represents the cumulative measurement deviation, and δ represents the effective capacity deviation.

15. The battery SOC calculation method according to claim 6, characterized in that: The calibrated battery capacity at the current moment is: SOCIETY t_c =SOC t-1 +Δfix_SOC t Among them, SOC t_c Indicates the current battery calibration capacity, SOC t-1 Indicates the battery capacity at the last moment, Δfix_SOC t Indicates the corrected battery capacity at the current moment.

16. The battery SOC calculation method according to claim 1, characterized in that: The secondary calibration of the actual battery power at the current moment includes: Based on the current charge level, current or voltage, and the target full charge level and charge cutoff current, or the target full discharge level and discharge cutoff voltage, predict the battery charge change at the current moment. Predicting the actual battery power at the current moment based on the predicted battery power change at the current moment and the battery power at the previous moment; Based on the predicted actual power of the battery at the current moment and the calibrated actual power of the battery at the current moment, the actual power of the battery at the current moment is calibrated twice so that it is synchronized to 100% when the current at the current moment reaches the charging cut-off current, or synchronized to 0% when the voltage at the current moment reaches the discharging cut-off voltage.

17. The battery SOC calculation method according to claim 16, characterized in that: The predicted battery charge change at the current moment is: Among them, ΔSOC predict Indicates the predicted battery charge change at the current moment, SOC 100％ Indicates the target full charge capacity, SOC t Indicates the current battery power, I eoc Indicates the target full charge current, I t represents the current battery charging current, and ΔI represents the current battery current change; or Among them, SOC 0％ Indicates the target full discharge capacity, V t Indicates the current battery voltage, V eod represents the target full-discharge voltage, and ΔV represents the battery voltage change at the current moment.

18. The battery SOC calculation method according to claim 16, characterized in that: The actual battery capacity at the current moment of the secondary calibration is: SOCIETY t_finnal =F(SOC t_c ,SOC t_p ) Among them, SOC t_finnal Indicates the secondary calibration capacity of the battery at the current moment, F() represents the fusion filter function, SOC t_c Indicates the current battery calibration capacity, SOC t_p Indicates the estimated battery capacity at the current moment.

19. The battery SOC calculation method according to claim 18, characterized in that: The fusion filter function F() is an arithmetic average filter function, a weighted average filter function, an inertial filter function, a Kalman filter function or an adaptive filter function, etc.

20. A battery SOC calculation device, characterized in that: include: Acquisition module, used to obtain battery charge and discharge parameters and operating parameters; A first calculation module, used to calculate the initial power of the battery; The second calculation module is used to calculate the open circuit voltage of the battery at the current moment; a calibration module, configured to calculate a calibration capacity of the battery at a current moment based on the open circuit compensation voltage; The secondary calibration module is used to predict the change in battery power at the current moment and calculate the actual battery power at the current moment based on the calibration power.

21. A battery management system, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of the battery SOC calculation method according to any one of claims 1 to 19 when running the computer program.

22. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the battery SOC calculation method according to any one of claims 1 to 19 are implemented.

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