A battery open-circuit voltage curve correction method, system, device and medium

Abstract

The application belongs to the technical field of battery testing, and provides a battery open-circuit voltage curve correction method, system, device and medium, wherein the method comprises: performing battery charging and discharging test in a target temperature range, and recording target data; calculating a boundary voltage difference of SOC based on the target data; performing linear fitting based on the target data to obtain a cut-off SOC-charging and discharging terminal voltage curve; performing extension on the cut-off SOC-charging and discharging terminal voltage curve based on the boundary voltage difference to obtain a complete SOC-charging and discharging terminal voltage curve; and constructing an OCV-SOC curve based on the complete SOC-charging and discharging terminal voltage curve. The application is based on the actually measured charging and discharging data of the battery at the target temperature, quantifies the polarization deviation of the target temperature through the boundary voltage difference, combines the linear fitting and extension technology, realizes the completion of the voltage curve in the full SOC interval, and solves the technical problems of curve distortion and interval loss at the extreme temperature in the traditional technology.

Description

Technical Field

[0001] This invention belongs to the field of battery testing technology, and specifically relates to a method, system, device and medium for correcting the open-circuit voltage curve of a battery. Background Technology

[0002] Lithium-ion batteries have been widely used in high-performance applications such as electric vehicles and energy storage systems due to their advantages such as high energy density and long cycle life. One of the functions of a battery management system (BMS) is to estimate the state of charge (SOC), and the open-circuit voltage (OCV) has a near monotonic relationship with SOC, making it a key basis for SOC estimation.

[0003] Traditional low-rate cycling methods are widely used for OCV testing due to their ability to quickly acquire high-resolution OCV-SOC data. However, at low temperatures, the internal resistance of lithium-ion batteries increases significantly, leading to enhanced polarization. This causes the charge / discharge terminal voltage to reach the cutoff threshold prematurely, resulting in early test termination and truncation of the measured OCV-SOC curve. This issue leads to an underestimation of the battery's usable capacity, a compressed SOC window, and consequently, SOC estimation errors, impacting BMS performance and battery operational safety.

[0004] Among existing solutions, the intermittent galvanostatic titration (GITT) technique requires a long period of rest to eliminate polarization, resulting in extremely low testing efficiency. Some studies have attempted to correct this by redefining the SOC boundary or adjusting the capacity loss coefficient, but these methods have not fundamentally solved the problem of curve truncation caused by polarization. Summary of the Invention

[0005] To address the problems in the background art, this invention proposes a method, system, device, and medium for correcting the open-circuit voltage curve of a battery.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for correcting the open-circuit voltage curve of a battery includes the following steps: Within the target temperature range, perform battery charge and discharge tests and record the target data, which includes the battery charge and discharge terminal voltage and the corresponding SOC at different temperatures. Calculate the boundary voltage difference of SOC based on the target data; Linear fitting is performed based on the target data to obtain the cutoff SOC-charge-discharge terminal voltage curve; The SOC-charge-discharge terminal voltage curve is extrapolated based on the boundary voltage difference to obtain the complete SOC-charge-discharge terminal voltage curve. The OCV-SOC curve is constructed based on the complete SOC-charge-discharge terminal voltage curve.

[0007] Furthermore, within a set temperature range and at the cutoff voltage, battery charge-discharge tests were conducted, and target data were recorded. Set the battery's charge / discharge rate, charging cut-off voltage, and discharging cut-off voltage; Within the target temperature range, charge and discharge tests are performed based on charge and discharge rates, charging cutoff voltage, and discharging cutoff voltage. Record the charging and discharging terminal voltages corresponding to the state of charge (SOC) at different temperatures.

[0008] Furthermore, the boundary voltage difference of SOC is calculated based on the target data, including the following steps: The boundary points are set as SOC=0 and SOC=100%; When SOC=0, calculate the difference between the charging terminal voltage and the discharging terminal voltage; When SOC=100%, calculate the difference between the charging terminal voltage and the discharging terminal voltage.

[0009] Furthermore, based on the target data, a linear fit is performed to obtain the cutoff SOC-charge / discharge termination voltage curve, including the following steps: Construct a mapping relationship between SOC and charging terminal voltage to obtain the cutoff SOC-charging terminal voltage curve; A mapping relationship between SOC and discharge terminal voltage is constructed to obtain the SOC-discharge terminal voltage curve at cutoff.

[0010] Furthermore, the SOC-charge-discharge termination voltage curve is extrapolated to obtain the complete SOC-charge-discharge termination voltage curve, including the following steps: Linear fitting is performed at several points at the cutoff point of the SOC-charging terminal voltage curve to obtain the first slope; linear fitting is performed at several points at the cutoff point of the SOC-discharging terminal voltage curve to obtain the second slope. Based on the SOC-charging terminal voltage curve with the first slope and the boundary voltage difference at SOC=100%, the complete SOC-charging terminal voltage curve is obtained; based on the SOC-discharging terminal voltage curve with the second slope and the boundary voltage difference at SOC=0, the complete SOC-discharging terminal voltage curve is obtained.

[0011] Furthermore, an OCV-SOC curve is constructed based on the complete SOC-charge / discharge terminal voltage curve, including the following steps: Calculate the average value of the charging terminal voltage and the discharging terminal voltage at each SOC point, and use the average value as the open circuit voltage; By summing up the SOC points and their corresponding open-circuit voltages, the OCV-SOC curve is obtained.

[0012] Furthermore, the cutoff voltage is 3.0~4.2V.

[0013] Furthermore, the target temperature is -25℃ to 5℃.

[0014] A battery open-circuit voltage curve correction system, comprising: The test unit is used to perform battery charge and discharge tests within a target temperature range and record target data, which includes the battery charge and discharge terminal voltage and corresponding SOC at different temperatures. A calculation unit is used to calculate the boundary voltage difference of the SOC based on the target data; The fitting unit is used to perform linear fitting based on the target data to obtain the cutoff SOC-charge-discharge terminal voltage curve. The epitaxial unit is used to extend the cutoff SOC-charge-discharge terminal voltage curve based on the boundary voltage difference to obtain the complete SOC-charge-discharge terminal voltage curve. The calibration unit is used to construct the OCV-SOC curve based on the complete SOC-charge-discharge terminal voltage curve.

[0015] An apparatus comprising: Memory, used to store computer programs; The processor implements the above method when executing computer programs stored in memory.

[0016] A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method.

[0017] The beneficial effects of this invention are: 1. Based on the measured charge and discharge data of the battery at the target temperature, this invention quantifies the polarization deviation of the target temperature by the boundary voltage difference. Combined with linear fitting and extrapolation techniques, it achieves the completion of the voltage curve across the entire SOC range, solving the technical problems of curve distortion and range loss under extreme temperatures in traditional technologies. 2. This invention uses the average charge and discharge voltage to calculate the open circuit voltage, which effectively counteracts the polarization interference of battery charge and discharge polarization under extreme temperatures, restores the battery's electrochemical balance characteristics, and the corrected curve closely matches the actual operating state of the battery. This can significantly improve the accuracy of SOC estimation and avoid problems such as battery overcharging, over-discharging, and capacity misjudgment.

[0018] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A simplified flowchart of a battery open-circuit voltage curve correction method according to the present invention is shown; Figure 2 A detailed flowchart of the calibration method of the present invention is shown; Figure 3a A three-dimensional point graph showing the temperature, SOC, and charging voltage of the present invention is shown; Figure 3b A three-dimensional point plot of temperature, SOC, and discharge voltage of the present invention is shown; Figure 4 A framework diagram of a battery open-circuit voltage curve correction system according to the present invention is shown. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] like Figure 1 The image shows a method for correcting the open-circuit voltage curve of a battery, which includes the following steps: S1: Within the target temperature range, perform battery charge and discharge tests and record the target data, which includes the battery charge and discharge terminal voltage and the corresponding SOC at different temperatures.

[0023] S2: Calculate the boundary voltage difference of SOC based on the target data.

[0024] S3: Based on the target data, perform linear fitting to obtain the cutoff SOC-charge / discharge terminal voltage curve.

[0025] S4: Based on the boundary voltage difference, the cutoff SOC-charge-discharge terminal voltage curve is extended to obtain the complete SOC-charge-discharge terminal voltage curve.

[0026] S5: Construct the OCV-SOC curve based on the complete SOC-charge / discharge terminal voltage curve.

[0027] It should be noted that the above method is based on measured data at the target temperature. It combines boundary voltage difference correction and curve extrapolation technology to make up for the lack of battery SOC boundary voltage data at the target temperature (especially at extreme temperatures). It solves the problems that traditional curves cannot adapt to temperature changes and have incomplete SOC range coverage, thereby improving the authenticity and adaptability of open circuit voltage curves under extreme conditions from the source.

[0028] like Figure 2 As shown, Figure 1 The method is applicable to testing under extreme temperature conditions. Before conducting extreme tests, data needs to be collected. The collected data is then input into the corresponding device to select whether to conduct tests under extreme temperature conditions. If testing is required, a complete OCV curve (OCV-SOC curve) is output. If not, a traditional test is performed to obtain a traditional OCV curve. Finally, the BMS can estimate the SOC of the battery using either the complete OCV curve or the traditional OCV curve.

[0029] Further steps, specifically in S1, include the following: S101: Set the battery's charge / discharge rate, charging cut-off voltage (preferably 4.2V), and discharging cut-off voltage (preferably 3.0V).

[0030] S102: Perform charge and discharge tests based on charge and discharge rates, charge cut-off voltage, and discharge cut-off voltage within the target temperature range.

[0031] S103: Record the charging terminal voltage and discharging terminal voltage corresponding to the SOC at different temperatures.

[0032] Optionally, a ternary lithium battery-nickel-manganese-cobalt (NMC) system lithium-ion battery is selected in S1. Charge-discharge cycle tests were conducted at a rate of C / 30 within a temperature range of 25℃ to 50℃. During the test, charging was stopped when the terminal voltage reached 4.2V, and discharging was stopped when the terminal voltage reached 3.0V. The terminal voltage corresponding to different states of charge (SOC) at each temperature was recorded simultaneously. and discharge terminal voltage .

[0033] It should be noted that at low temperatures, the battery's internal resistance is high and polarization is severe, causing the charging and discharging voltage to reach the set cutoff voltage prematurely, thus aborting the test. Therefore, using voltage as the shutdown trigger condition ultimately cuts off the SOC range, failing to fully cover 0-100%.

[0034] Furthermore, S2 specifically includes the following steps: S201: Set the boundary points as SOC=0 (battery unloaded) and SOC=100% (battery fully charged).

[0035] S202: When SOC=0, calculate the difference between the charging terminal voltage and the discharging terminal voltage, using the following formula: ; In the formula, where This is the charging terminal voltage when SOC=0%. ) is the discharge terminal voltage when SOC=0%.

[0036] S203: When SOC=100%, calculate the difference between the charging terminal voltage and the discharging terminal voltage using the following formula: ); In the formula, where This is the charging terminal voltage when SOC=100%. This is the discharge termination voltage when SOC=100%.

[0037] It should be noted that the SOC zero point and full point are critical nodes in the battery's charge and discharge states. At extreme temperatures, the polarization voltage deviation at these nodes is the largest and has the most significant impact on the curve. By calculating the voltage difference at the boundaries, the battery polarization offset caused by extreme temperatures can be quantified, providing correction parameters for subsequent curve extrapolation correction. Moreover, since the curve is truncated, when calculating the boundary points, the theoretically corresponding charging and discharging terminal voltages for SOC=0 and SOC=100% can be calculated by linear extrapolation from the existing truncated charge-discharge fitting curve.

[0038] Furthermore, S3 includes the following steps: based on the collected charging terminal voltage data of multiple temperatures and multiple SOC nodes, a one-to-one mapping relationship between SOC values ​​and charging terminal voltages is constructed, and the dataset is processed by a linear fitting algorithm to generate a cutoff SOC-charging terminal voltage curve; at the same time, based on the collected discharging terminal voltage data, a mapping relationship between SOC values ​​and discharging terminal voltages is constructed, and a cutoff SOC-discharging terminal voltage curve is generated by linear fitting.

[0039] It should be noted that S3 distinguishes the differential characteristics of battery charging polarization and discharging polarization under extreme temperatures by fitting the charging and discharging curves, avoiding the problem of polarization feature confusion caused by fitting a single curve, restoring the true change law of battery charging and discharging terminal voltage with SOC under extreme temperatures, and providing a piecewise basic curve for subsequent curve extrapolation and open circuit voltage calculation.

[0040] It should be noted that, taking a cutoff voltage range of 3.2~4.2 as an example, such as... Figure 3aAs shown, this three-dimensional scatter plot represents the relationship between charging terminal voltage, temperature, and SOC. The horizontal X-axis represents temperature (-30℃~50℃), the vertical Y-axis represents SOC (0~100%), and the vertical Z-axis represents charging terminal voltage (3.2V~4.2V). The data points exhibit a linear distribution: at a fixed temperature, the charging terminal voltage and SOC are positively linearly correlated; at a fixed SOC, the charging terminal voltage and temperature are negatively linearly correlated.

[0041] like Figure 3b As shown, the title of this three-dimensional scatter plot is "Relationship between Discharge Terminal Voltage, Temperature and SOC". The X-axis shows the temperature range of -30℃ to 50℃, the Y-axis shows the SOC range of 0 to 100%, and the Z-axis shows the discharge terminal voltage of 3.0V to 4.2V. The distribution characteristics are as follows: at a fixed temperature, the discharge terminal voltage is positively linearly correlated with the SOC, and at a fixed SOC, the discharge terminal voltage is positively linearly correlated with the temperature.

[0042] Furthermore, S4 includes the following steps: S401: Take several points at the cutoff point of the SOC-charging terminal voltage curve and perform linear fitting to obtain the first slope; take several points at the cutoff point of the SOC-discharging terminal voltage curve and perform linear fitting to obtain the second slope.

[0043] S402: Based on the SOC-charging terminal voltage curve with the boundary voltage difference at SOC=100% and the first slope, the complete SOC-charging terminal voltage curve is obtained; based on the SOC-discharging terminal voltage curve with the boundary voltage difference at SOC=0 and the second slope, the complete SOC-discharging terminal voltage curve is obtained.

[0044] Optionally, combined Figure 2 It can be seen that when extending the SOC-discharge terminal voltage curve, five data points (time-terminal voltage) at the end of the original discharge curve are selected, and a linear fit is performed using the least squares method to obtain the discharge curve fitting slope (second slope); then, five data points at the beginning of the original charging curve are selected, and a linear fit is performed again, with the negative value taken. This negative value is then averaged with the discharge curve fitting slope to obtain the final extrapolated slope; based on this slope and... The discharge curve is pushed downwards and outwards until the extended discharge terminal voltage meets the minimum OCV requirement of 3.0V.

[0045] Extending the SOC-charging terminal voltage curve at the cutoff point: 650 data points from the end of the original charging curve were selected, and linear fitting was performed using the least squares method to obtain the charging curve fitting slope (first slope); based on this slope and... The charging curve is pushed upwards and outwards until the extended charging terminal voltage meets the requirement of the maximum OCV value of 4.2V.

[0046] Furthermore, S5 includes the following steps: Traverse all sampling nodes within the entire SOC range, extract the complete charging terminal voltage and discharging terminal voltage corresponding to each SOC point, calculate the average value of the two sets of voltages, and define the average value as the battery open-circuit voltage of the corresponding SOC node; then, summarize all SOC nodes and their corresponding open-circuit voltage data, complete data fitting and processing, and generate a complete OCV-SOC curve adapted to extreme temperature environments.

[0047] It should be noted that S5 effectively counteracts polarization voltage interference during battery charging and discharging at extreme temperatures by averaging the charging and discharging terminal voltages, thus restoring the true electrochemical equilibrium state inside the battery. The resulting OCV-SOC curve closely matches the true characteristics of the battery under extreme temperature conditions.

[0048] The following uses a lithium-ion battery as an example, with a cutoff voltage of 3.0~4.2V and a target temperature of -25~50℃. The test results at the target temperature are as follows: Select three lithium-ion batteries and calibrate them according to the following steps: First, a charge / discharge test is performed: Charge and discharge tests were conducted at a C / 30 rate under four typical temperatures: 25℃, 0℃, 25℃, and 50℃. The charging cutoff voltage was 4.2V, and the discharging cutoff voltage was 3.0V. The corresponding data of the charging and discharging terminal voltage and SOC at each temperature were recorded.

[0049] Voltage difference calculation: In At 25℃, when SOC=0%: ; ; When SOC=100%: ; ; Curve extrapolation: The slope of the fitted curve is selected from the last 5 data points of the discharge curve. The charging rate is 0.02V / h. The slope of the first 5 data points of the charging curve is 0.03V / h. After taking the negative value, the slope is averaged with the slope of the discharging curve to obtain the extrapolated slope. 0.025V / h; based on ΔV D =0.71V, the discharge curve is pushed down to 2.31V; the slope of the 650 data points at the end of the charging curve is 0.01V / h, based on ΔV C =0.081V, push it upwards to 4.281V.

[0050] OCV reconstruction: The average voltage at the SOC point corresponding to the extrapolated charge-discharge curve is obtained. The OCV-SOC curve after correction at 25℃ shows that OCV = 3.0V when SOC = 0% and OCV = 4.2V when SOC = 100%, covering the target voltage range.

[0051] The correction effect was then quantitatively analyzed using three types of evaluation indicators. Details of each indicator are as follows: 1) High and low end offset characteristics: After correction using this method, the OCV offset at both SOC=0% and SOC=100% operating conditions across the entire temperature range is reduced to 0V; in contrast, the traditional solution... At a low temperature of 25℃, the OCV offset in the low SOC range can reach 0.3476V, demonstrating the significant advantages of this correction method.

[0052] 2) Cell consistency difference: The standard deviation of OCV difference of cells in the medium and high SOC range (SOC≥0.4) is controlled within 30mV, which is 40% lower than the traditional method.

[0053] 3) Temperature-induced deviation: Under 25℃ operating conditions, the temperature-induced OCV difference width in the high SOC range does not exceed 100mV, which is a significant reduction compared to the 600mV deviation level of the traditional method.

[0054] The comprehensive verification results confirm that the correction method proposed in this paper can completely and uniformly restore the OCV curve under extreme temperature conditions, effectively improving the accuracy of SOC estimation.

[0055] like Figure 4 The diagram illustrates a battery open-circuit voltage curve correction system, comprising a testing unit, a calculation unit, a fitting unit, an extrapolation unit, and a correction unit. The testing unit performs battery charge-discharge tests within a target temperature range and records target data, which includes the battery charge-discharge terminal voltage and corresponding State of Charge (SOC) at different temperatures. The calculation unit calculates the boundary voltage difference of SOC based on the target data. The fitting unit performs linear fitting based on the target data to obtain a cutoff SOC-charge-discharge terminal voltage curve. The extrapolation unit extrapolates the cutoff SOC-charge-discharge terminal voltage curve based on the boundary voltage difference to obtain a complete SOC-charge-discharge terminal voltage curve. The correction unit constructs an OCV-SOC curve based on the complete SOC-charge-discharge terminal voltage curve.

[0056] It should be noted that, for the system embodiment, since it basically corresponds to the method embodiment, the relevant parts can be referred to in the description of the method embodiment. The various units and modules of a battery open-circuit voltage curve correction system are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each unit are only for easy distinction between each other and are not used to limit the protection scope of the present invention.

[0057] The present invention also proposes an apparatus comprising: Memory, used to store computer programs; When a processor executes a computer program stored in memory, it implements the aforementioned method for correcting the open-circuit voltage curve of a battery.

[0058] It should be noted that the memory may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device.

[0059] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0060] The present invention also proposes a computer-readable storage medium storing a computer program thereon, characterized in that the computer program, when executed by a processor, implements the above-described method for correcting the open-circuit voltage curve of a battery.

[0061] It should be noted that the computer-readable storage medium may be included in the device / apparatus described in the above embodiments; or it may exist independently and not assembled into the device / apparatus. The computer-readable storage medium carries one or more programs, which, when executed, implement a battery open-circuit voltage curve correction method according to an embodiment of the present invention.

[0062] According to embodiments of the present invention, the computer-readable storage medium may be a non-volatile computer-readable storage medium, such as: a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In the present invention, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0063] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for correcting the open-circuit voltage curve of a battery, characterized in that, Includes the following steps: Within the target temperature range, perform battery charge and discharge tests and record target data, which includes the battery charge and discharge terminal voltage and corresponding SOC at different temperatures; Calculate the boundary voltage difference of SOC based on the target data; Linear fitting is performed based on the target data to obtain the cutoff SOC-charge-discharge terminal voltage curve; The SOC-charge-discharge terminal voltage curve is extrapolated based on the boundary voltage difference to obtain the complete SOC-charge-discharge terminal voltage curve. The OCV-SOC curve is constructed based on the complete SOC-charge-discharge terminal voltage curve.

2. The battery open-circuit voltage curve correction method according to claim 1, characterized in that, Within the set temperature range, perform battery charge-discharge tests at the cutoff voltage and record the target data: Set the battery's charge / discharge rate, charging cut-off voltage, and discharging cut-off voltage; Within the target temperature range, charge and discharge tests are performed based on charge and discharge rates, charging cutoff voltage, and discharging cutoff voltage. Record the charging and discharging terminal voltages corresponding to the state of charge (SOC) at different temperatures.

3. The battery open-circuit voltage curve correction method according to claim 1, characterized in that, The calculation of the boundary voltage difference of SOC based on the target data includes the following steps: The boundary points are set as SOC=0 and SOC=100%; When SOC=0, calculate the difference between the charging terminal voltage and the discharging terminal voltage; When SOC=100%, calculate the difference between the charging terminal voltage and the discharging terminal voltage.

4. The battery open-circuit voltage curve correction method according to claim 1, characterized in that, Based on the target data, a linear fit is performed to obtain the cutoff SOC-charge / discharge termination voltage curve, including the following steps: Construct a mapping relationship between SOC and charging terminal voltage to obtain the cutoff SOC-charging terminal voltage curve; A mapping relationship between SOC and discharge terminal voltage is constructed to obtain the SOC-discharge terminal voltage curve at cutoff.

5. The battery open-circuit voltage curve correction method according to claim 4, characterized in that, Extrapolating the cutoff SOC-charge-discharge termination voltage curve to obtain the complete SOC-charge-discharge termination voltage curve includes the following steps: Linear fitting is performed at several points at the cutoff point of the SOC-charging terminal voltage curve to obtain the first slope; linear fitting is performed at several points at the cutoff point of the SOC-discharging terminal voltage curve to obtain the second slope. Based on the SOC-charging terminal voltage curve with the first slope and the boundary voltage difference at SOC=100%, the complete SOC-charging terminal voltage curve is obtained; based on the SOC-discharging terminal voltage curve with the second slope and the boundary voltage difference at SOC=0, the complete SOC-discharging terminal voltage curve is obtained.

6. The battery open-circuit voltage curve correction method according to claim 5, characterized in that, Constructing the OCV-SOC curve based on the complete SOC-charge / discharge termination voltage curve includes the following steps: Calculate the average value of the charging terminal voltage and the discharging terminal voltage at each SOC point, and use the average value as the open circuit voltage; By summing up the SOC points and their corresponding open-circuit voltages, the OCV-SOC curve is obtained.

7. A battery open-circuit voltage curve correction method according to any one of claims 1-6, characterized in that, The cutoff voltage is 3.0~4.2V.

8. A battery open-circuit voltage curve correction method according to any one of claims 1-6, characterized in that, The target temperature is -25℃ to 5℃.

9. A battery open-circuit voltage curve correction system, characterized in that, include: The test unit is used to perform battery charge and discharge tests within a target temperature range and record target data, which includes the battery charge and discharge terminal voltage and corresponding SOC at different temperatures. A calculation unit is used to calculate the boundary voltage difference of the SOC based on the target data; The fitting unit is used to perform linear fitting based on the target data to obtain the cutoff SOC-charge-discharge terminal voltage curve. The epitaxial unit is used to extend the cutoff SOC-charge-discharge terminal voltage curve based on the boundary voltage difference to obtain the complete SOC-charge-discharge terminal voltage curve. The calibration unit is used to construct the OCV-SOC curve based on the complete SOC-charge-discharge terminal voltage curve.

10. A device, characterized in that, include: Memory, used to store computer programs; A processor, when executing a computer program stored in a memory, implements a battery open-circuit voltage curve correction method according to any one of claims 1-8.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements a battery open-circuit voltage curve correction method according to any one of claims 1-8.

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