Battery open-circuit voltage correction method and device, vehicle, medium and product

Abstract

The embodiment of the invention provides a battery open-circuit voltage correction method and device, a vehicle, a medium and a product. The method comprises the following steps: when the standing time of a to-be-tested battery represents that the to-be-tested battery does not enter a steady-state response, determining the polarization voltage of the to-be-tested battery in the standing time according to the polarization attenuation degree of the to-be-tested battery; the polarization attenuation degree of the to-be-detected battery is determined according to the standing time and the polarization time constant of the to-be-detected battery; and according to the polarization voltage of the to-be-measured battery in the standing time, correcting the open-circuit voltage of the to-be-measured battery obtained in the standing time to obtain the corrected open-circuit voltage of the to-be-measured battery. The method is used for achieving the effect of improving the measurement accuracy of the OCV.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle battery, in particular to a battery open circuit voltage correction method, device, vehicle, medium and product. BACKGROUND

[0002] In the field of electric vehicles (EV) and energy storage systems (ESS), battery state estimation technology is considered as the core link to ensure system safety and improve operational efficiency. With the continuous growth of global demand for clean energy and the increasing awareness of environmental protection, the application scale of electric vehicles and renewable energy storage systems has rapidly expanded. As the core component of these systems, the performance of the battery directly determines the operational efficiency, service life and safety of the overall system. Among many battery state parameters, the battery state of charge (SOC) is particularly important. SOC is defined as the ratio of the current remaining capacity to the full charge capacity of the battery, and is a key indicator of battery energy reserves.

[0003] Traditional battery state of charge (SOC) estimation methods mainly rely on the known relationship between open circuit voltage (OCV) and SOC to estimate. OCV is the terminal voltage measured under no load conditions, and it has a one-to-one correspondence with the SOC of the battery.

[0004] However, due to the polarization effect caused by the complex chemical reactions inside the battery and the changes in the external environment temperature, it becomes complex to determine the SOC directly by measuring the OCV. In order to obtain an accurate OCV value, the battery usually needs to be in a stationary state for a long enough time (usually more than 2 hours) to ensure that the battery is in a relatively balanced state; but in actual application, due to the long waiting time and the susceptibility to external interference, the measurement result of the OCV has the technical problem of inaccuracy. SUMMARY

[0005] The embodiments of the present application provide a battery open circuit voltage correction method, device, vehicle, medium and product to improve the measurement accuracy of OCV.

[0006] In a first aspect, the embodiments of the present application provide a battery open circuit voltage correction method, the method comprising:

[0007] When the rest time of the battery to be measured represents that the battery to be measured has not entered a steady state response, the polarization voltage of the battery to be measured at the rest time is determined according to the polarization decay degree of the battery to be measured; the polarization decay degree of the battery to be measured is determined according to the rest time of the battery to be measured and the polarization time constant;

[0008] The open circuit voltage obtained at the rest time of the battery under test is corrected according to the polarization voltage of the battery under test at the rest time, to obtain a corrected open circuit voltage of the battery under test.

[0009] In a possible implementation, the polarization voltage of the battery under test at the rest time is determined according to the polarization decay degree of the battery under test, and the method comprises:

[0010] An initial polarization voltage of the battery under test is obtained, and the initial polarization voltage is determined according to the decay change degree and the open circuit change voltage corresponding to different rest times of the battery under test;

[0011] The polarization voltage of the battery under test at the rest time is determined according to the polarization decay degree and the initial polarization voltage of the battery under test.

[0012] In a possible implementation, the method further comprises:

[0013] A previous open circuit voltage and a previous polarization decay degree corresponding to a previous rest time of the battery under test are determined, and the previous rest time is a time before the rest time and meets the rest time difference requirement;

[0014] The open circuit change voltage is determined according to the previous open circuit voltage and the open circuit voltage;

[0015] The decay change degree is determined according to the previous polarization decay degree and the polarization decay degree;

[0016] The initial polarization voltage is determined according to the open circuit change voltage and the decay change degree.

[0017] In a possible implementation, the method further comprises:

[0018] The polarization decay degrees corresponding to different times of the battery under test are determined;

[0019] The target polarization decay degree and the time corresponding to the target polarization decay degree are determined according to the change of the polarization decay degree over time;

[0020] When the rest time of the battery under test is less than the time corresponding to the target polarization decay degree, it is determined that the rest time of the battery under test represents that the battery under test has not entered a steady state response.

[0021] In a possible implementation, the method further comprises:

[0022] The real part and the imaginary part of the impedance of the battery under test are obtained, and the real part and the imaginary part of the impedance of the battery under test are obtained by discrete Fourier transform on the pulse current and the response voltage, and the response voltage is the voltage of the battery under test under the action of the pulse current;

[0023] The polarization time constant of the battery under test is determined according to the real part and the imaginary part of the impedance of the battery under test.

[0024] In a possible implementation, the polarization time constant of the battery under test is determined according to the real part and the imaginary part of the impedance of the battery under test, including:

[0025] The real part and the imaginary part of the impedance of the battery under test at different frequencies are fitted according to the equivalent circuit model corresponding to the battery under test, to obtain the electrical data and the concentration polarization of the electrochemical polarization and the polarization time of the electrochemical polarization and the polarization time of the concentration polarization in the equivalent circuit model;

[0026] The polarization time constant of the battery under test is determined according to the polarization time of the electrochemical polarization and the polarization time of the concentration polarization.

[0027] In a possible implementation, the polarization time constant of the battery under test is determined according to the real part and the imaginary part of the impedance of the battery under test, including:

[0028] The real part and the imaginary part of the impedance of the battery under test at different frequencies are subjected to relaxation time distribution processing, to obtain the time constant corresponding to different relaxation times;

[0029] The polarization time constant of the battery under test is determined according to the time constant corresponding to different relaxation times.

[0030] In a possible implementation, the real part and the imaginary part of the impedance of the battery under test are obtained when the vehicle of the battery under test satisfies at least one preset condition.

[0031] The preset condition includes:

[0032] The timer of the vehicle reaches a set time;

[0033] The vehicle is in an unlocked state;

[0034] The door of the vehicle is in an open state.

[0035] In a possible implementation, the method further includes:

[0036] The internal temperature of the battery under test and the temperature correction coefficient of the internal temperature of the battery under test are obtained; the internal temperature of the battery under test is determined according to the real part and the imaginary part of the impedance of the battery under test, and the amplitude and the phase determined according to the real part and the imaginary part of the impedance of the battery under test;

[0037] The open-circuit voltage is corrected according to the temperature correction coefficient corresponding to the internal temperature of the battery, to obtain a target open-circuit voltage;

[0038] Alternatively,

[0039] The method further includes:

[0040] When the standing time of the battery to be measured represents that the battery to be measured enters a steady-state response, and the standing time of the battery to be measured does not exceed the preset standing time, the battery internal temperature of the battery to be measured is acquired, and a temperature correction coefficient corresponding to the battery internal temperature is acquired;

[0041] The open-circuit voltage of the battery to be measured acquired at the standing time is corrected according to the temperature correction coefficient corresponding to the battery internal temperature, to obtain a target open-circuit voltage.

[0042] In a second aspect, an embodiment of the present application provides a battery open-circuit voltage correction device, including:

[0043] The determination module is configured to, when the standing time of the battery to be measured represents that the battery to be measured does not enter a steady-state response, determine the polarization voltage of the battery to be measured at the standing time according to a polarization decay degree of the battery to be measured, and determine the polarization decay degree of the battery to be measured according to the standing time and a polarization time constant of the battery to be measured.

[0044] The obtaining module is configured to correct the open-circuit voltage of the battery to be measured acquired at the standing time according to the polarization voltage of the battery to be measured at the standing time, to obtain a corrected open-circuit voltage of the battery to be measured.

[0045] In a third aspect, an embodiment of the present application provides a vehicle, including a memory and a processor.

[0046] The memory stores computer execution instructions.

[0047] The processor executes the computer execution instructions stored in the memory, so that the processor executes the first aspect and / or various possible implementation manners of the first aspect.

[0048] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium stores computer execution instructions. When the computer execution instructions are executed by a processor, the computer execution instructions are used to implement the first aspect and / or various possible implementation manners of the first aspect.

[0049] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program. When the computer program is executed by a processor, the computer program implements the first aspect and / or various possible implementation manners of the first aspect.

[0050] The battery open-circuit voltage correction method, device, vehicle, medium and product provided by the embodiment of the application, by judging the attenuation degree of the internal polarization of the battery according to the standing time and the known polarization time constant when the battery is not completely at rest and stable, and calculating the polarization voltage under the current standing time, and then correcting the measured open-circuit voltage by using the polarization voltage, which is equivalent to dynamically compensating the voltage data of the battery when the battery is not completely stable. Therefore, by introducing the polarization time constant and the attenuation degree for quantitative analysis and correction, the open-circuit voltage value closer to the real state is derived, so as to improve the accuracy of the battery state of charge (SOC) estimation, and achieve the effect of high-precision open-circuit voltage correction and state estimation under non-steady-state conditions. BRIEF DESCRIPTION OF DRAWINGS

[0051] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0052] Figure 1 A scene schematic diagram of the battery open-circuit voltage correction method provided by the application;

[0053] Figure 2 A flowchart of the battery open-circuit voltage correction method provided by the application;

[0054] Figure 2a A test system schematic diagram of the battery to be tested for EIS test provided by the embodiment of the application;

[0055] Figure 2b A model schematic diagram of the equivalent circuit model provided by the embodiment of the application;

[0056] Figure 2c A relaxation time decomposition schematic diagram provided by the embodiment of the application;

[0057] Figure 2d A schematic diagram of SOC and OCV at different temperatures provided by the embodiment of the application;

[0058] Figure 3 A flowchart of another battery open-circuit voltage correction method provided by the application;

[0059] Figure 4 A structure schematic diagram of the battery open-circuit voltage correction device provided by the application;

[0060] Figure 5 A structure schematic diagram of the vehicle provided by the application.

[0061] The specific embodiments of the application have been shown by way of example in the above figures, and will be described in greater detail below. These figures and this written description are not intended to limit the scope of the inventive concept in any way, but rather to illustrate the inventive concept to one of ordinary skill in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0062] Exemplary embodiments will be described in detail herein with reference to the attached drawings. The same or similar components are denoted by the same or similar reference numerals throughout the drawings and the written description, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not meant to represent all embodiments consistent with the application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the application as detailed in the appended claims.

[0063] First, the terms related to the present application are explained:

[0064] Open circuit voltage (OCV) refers to the potential difference between the positive and negative electrodes of a battery when there is no external load, i.e., the circuit is in an open state. It is an important parameter reflecting the internal chemical state of the battery, and is usually closely related to the state of charge (SOC) of the battery, and can be used to assess the remaining capacity and health status of the battery.

[0065] Currently, the existing solution is to ensure that the battery internal temperature is balanced and the battery depolarization is accurate by resting for a long time (usually more than 2 hours) to measure OCV. However, this method has many limitations in practical application, such as frequent charging of vehicles during driving, short parking time, etc., which may not meet the requirement of long time resting.

[0066] The battery open circuit voltage correction method, device, vehicle, medium and program provided by the present application can correct the measured open circuit voltage by determining the polarization voltage of the vehicle at the current resting time, solving the technical problem of inaccurate measurement of OCV.

[0067] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present application will be described below with reference to the drawings.

[0068] Figure 1 The scene diagram of the battery open circuit voltage correction method provided by the present application is as follows: Figure 1As shown, a specific application scenario for this application can be a vehicle controller. The vehicle controller can be a battery management system (BMS) for real-time monitoring of battery status, management of the charging and discharging process, and optimization of battery performance; it can also be a vehicle control unit (VCU) or energy management controller (EMC) responsible for coordinating the collaborative operation of the power battery with other vehicle systems. These controllers can all integrate the technical solutions of this application to improve the accuracy and response speed of battery status judgment under different operating conditions.

[0069] The vehicle control method in this application does not impose any particular restrictions on the implementation of the execution subject. As long as the execution subject can determine the polarization voltage of the battery under test during the resting time, which indicates that the battery under test has not entered a steady-state response, based on the degree of polarization decay of the battery under test; the degree of polarization decay of the battery under test is determined based on the resting time and polarization time constant of the battery under test; and the open-circuit voltage of the battery under test obtained during the resting time is corrected based on the polarization voltage of the battery under test during the resting time to obtain the corrected open-circuit voltage of the battery under test.

[0070] Figure 2 This application provides a flowchart illustrating a battery open-circuit voltage correction method, as shown below. Figure 2 As shown, the method includes:

[0071] S201. When the resting time of the battery under test indicates that the battery under test has not entered a steady-state response, the polarization voltage of the battery under test during the resting time is determined according to the degree of polarization decay of the battery under test; the degree of polarization decay of the battery under test is determined according to the resting time and polarization time constant of the battery under test.

[0072] The resting time of the battery under test refers to the period of recovery and internal state adjustment that the battery undergoes after charging and discharging operations have stopped under no-load conditions. During this period, as the resting time increases, non-steady-state processes that may occur inside the battery under test, such as electrochemical polarization, concentration gradients, and temperature changes, will gradually weaken, causing the open-circuit voltage (OCV) of the battery under test to gradually tend towards a more stable value.

[0073] Steady-state response refers to the state in which key parameters of the battery under test, such as voltage, current, and ion concentration distribution, stabilize after a certain period of recovery under no external load, and no longer change significantly over time. In the embodiments of this application, if the battery under test does not enter a steady-state response, it indicates that there are still dynamic non-equilibrium processes inside, such as polarization effects, diffusion processes, or response delays caused by temperature. In this case, the measured OCV is inaccurate and may lead to a large error in the SOC estimation.

[0074] The polarization decay degree of the battery under test can refer to the degree of gradual weakening of the polarization effect (such as activation polarization, concentration polarization, and ohmic polarization) inside the battery under test due to charging and discharging over time during the resting process. After the battery stops charging and discharging, its terminal voltage gradually approaches the open-circuit voltage over time, which reflects the decay of the polarization phenomenon. The greater the polarization decay degree, the more fully the non-equilibrium electrochemical state inside the battery recovers, and the closer the open-circuit voltage is to the OCV value that truly reflects the state of charge (SOC), thereby helping to improve the accuracy of SOC estimation.

[0075] The polarization decay degree of the battery under test can be determined according to the resting time of the battery under test and the polarization time constant, which can refer to the time constant of the polarization state and is used to reflect the degree of fast or slow decay of the polarization voltage inside the battery due to electrochemical reaction hysteresis over time after charging and discharging ends. Among them, the polarization voltage of the battery under test can decay according to an exponential law over time, and the decay rate is determined by the polarization time constant: the smaller the polarization time constant, the faster the polarization recovery; the greater the polarization time constant, the slower the recovery process. Through the polarization time constant, combined with the resting time of the battery under test, the polarization decay degree of the current battery can be quantitatively evaluated.

[0076] The polarization voltage of the resting time can refer to the additional voltage remaining inside the battery under test due to electrochemical polarization effects (such as activation polarization, concentration polarization, etc.) over time after the battery under test stops charging and discharging and enters a resting state. This voltage is not the true open-circuit voltage of the battery, but is offset from the open-circuit voltage, and the voltage will gradually decay as the resting time extends.

[0077] S202, according to the polarization voltage of the battery under test at the resting time, correcting the open-circuit voltage of the battery under test obtained at the resting time to obtain the corrected open-circuit voltage of the battery under test.

[0078] Among them, after determining the polarization voltage of the battery under test at the resting time, since the polarization voltage represents the additional voltage remaining inside due to electrochemical polarization effects (such as activation polarization, concentration polarization, etc.), the open-circuit voltage of the battery under test obtained at the resting time can be subtracted from the polarization voltage to obtain the corrected open-circuit voltage of the battery under test.

[0079] The battery open-circuit voltage correction method provided by the embodiments of the present application can be used to determine the polarization attenuation degree of the battery to be measured based on the actual resting time of the battery and the inherent polarization time constant when it is detected that the resting time of the battery to be measured is short and the internal electrochemical state has not reached a steady state (i.e., the polarization effect has not been completely eliminated), and estimate the residual polarization voltage of the battery to be measured at the resting time, so that the estimated polarization voltage is used to correct the current measured open-circuit voltage, and a corrected open-circuit voltage closer to the real equilibrium state is obtained, and high-precision open-circuit voltage measurement can be realized under the premise that the battery to be measured is not fully rested, thereby improving the accuracy and real-time performance of SOC estimation.

[0080] In the embodiments of the present application, the method further includes:

[0081] determining the polarization attenuation degrees corresponding to different times of the battery to be measured;

[0082] determining the target polarization attenuation degree and the time corresponding to the target polarization attenuation degree according to the change of the polarization attenuation degrees with time;

[0083] When the resting time of the battery to be measured is less than the time corresponding to the target polarization attenuation degree, it is determined that the resting time of the battery to be measured represents that the battery to be measured has not entered the steady-state response.

[0084] In the embodiments of the present application, the method further includes:

[0085] For example, the polarization attenuation degree can be determined according to the formula , wherein t is the time, and is the polarization time constant. As the time t increases, the obtained polarization attenuation degree will exponentially decay. Therefore, for different times, the polarization attenuation degrees corresponding to different times of the battery to be measured can be obtained.

[0086] After the polarization attenuation degrees corresponding to different times of the battery to be measured are determined, the target polarization attenuation degree and the time corresponding to the target polarization attenuation degree can be determined according to the change of the polarization attenuation degrees.

[0087] The change in the polarization decay degree can refer to a change in a polarization effect value of the battery under test caused by charging and discharging gradually weakening over time according to a formula of the polarization decay degree. The obtained polarization decay degree can exponentially decay, and the change can be an exponential decay of a value corresponding to the polarization decay degree.

[0088] The target polarization decay degree can represent a turning point at which the polarization decay degree of the battery under test enters a slow decay stage from a fast decay stage, and the turning point can be used as a judgment node of whether the battery under test enters a steady-state response. The time corresponding to the target polarization decay degree can be the time of the turning point.

[0089] In the embodiments of the present application, after obtaining the polarization decay degrees corresponding to different times, the time interval in which the decay rate or change rate (i.e., the change) corresponding to adjacent times is most significant is found. That is, the decay behavior reaches a peak in absolute amplitude and relative rate in the time interval, representing that the battery under test is experiencing a transition from fast relaxation to slow relaxation. The polarization decay degree corresponding to the end of the time interval of the most significant change is determined as the target polarization decay degree.

[0090] For example, in different unit times, the polarization decay degrees are 0.368, 0.136, 0.050, 0.018, 0.007, and 0.002, respectively. Since the change from 0.136 to 0.050 is the most significant, the polarization decay degree corresponding to 0.050 can be used as the target polarization decay degree, and the time required to reach the decay degree can be used as the time at which the battery under test enters a steady-state response.

[0091] Therefore, by quantifying the dynamic change in the polarization recovery process, a more accurate judgment basis than a fixed resting time is provided, which helps to improve the accuracy of open-circuit voltage measurement and state-of-charge estimation.

[0092] When the actual resting time of the battery is less than the time required to reach the target polarization decay degree, it indicates that the polarization effect in the battery has not fully subsided, and the open-circuit voltage is still in a dynamic recovery process. Therefore, it can be determined that the battery has not entered a steady-state response state at this time.

[0093] The polarization time constant of the battery under test needs to be measured, that is, in the embodiments of the present application, the method for determining the polarization time constant can further include:

[0094] The real part and the imaginary part of the impedance of the battery under test are obtained, and the real part and the imaginary part of the impedance of the battery under test are obtained by discrete Fourier transform of the pulse current and the response voltage, and the response voltage is the voltage of the battery under test under the action of the pulse current.

[0095] According to the real part and the imaginary part of the impedance of the battery to be measured, the polarization time constant of the battery to be measured is determined.

[0096] The real part of the impedance of the battery to be measured represents the equivalent resistance component of the battery at the frequency (related to ohmic resistance and charge transfer process), and the imaginary part of the impedance of the battery to be measured represents the reactance component of the battery (mainly reflecting the phase delay caused by polarization effect and diffusion process). The real part and the imaginary part of the impedance of the battery to be measured together describe the electrochemical response characteristics of the battery under dynamic working conditions.

[0097] Alternatively, the real part and the imaginary part of the impedance of the battery to be measured can be determined by performing EIS test on the battery to be measured, wherein the EIS test (Electrochemical Impedance Spectroscopy) can refer to a key technology for analyzing the internal reaction mechanism and interface characteristics of electrochemical systems such as batteries, fuel cells, supercapacitors, etc. The test obtains the impedance information of the battery at different frequencies by applying a small-amplitude alternating sinusoidal voltage or current signal to both ends of the battery and measuring the corresponding current or voltage response.

[0098] Figure 2a A test system schematic diagram for performing EIS test on the battery to be measured provided by the embodiments of the present application is shown in FIG. 1. Figure 2a As shown in FIG. 1, when starting the EIS test, the BECM (Battery Management System) sends an instruction to the excitation source to perform pulse current excitation. The BECM sends an instruction to the CMC (Battery Monitor Controller) to perform the EIS test. The pulse current generated by the excitation source acts on the battery to be measured. The battery to be measured forms a response voltage under the action of the excitation current. The CMC measures the pulse current and the response voltage and performs discrete Fourier transform DFT to obtain the impedance real part (Z') and the impedance imaginary part (Z'') of each battery.

[0099] In some embodiments, the Nyquist plot composed of the real part data and the imaginary part data of the impedance of the battery to be measured is analyzed. Since the real part and the imaginary part of the impedance of the battery to be measured in the plot present a specific curve shape relationship, wherein the high-frequency region mainly reflects the ohmic resistance, and the low-frequency region is related to the diffusion process and the polarization effect. By fitting the semicircle or inclined line part in the low-frequency region, the equivalent circuit parameters related to electrochemical polarization can be extracted, such as charge transfer resistance and capacitance, etc. Based on these parameters, the polarization time constant can be calculated.

[0100] In the embodiments of the present application, the polarization time constant of the battery to be measured is determined according to the real part and the imaginary part of the impedance of the battery to be measured, comprising:

[0101] According to the equivalent circuit model corresponding to the to-be-tested battery, the real part and the imaginary part of the impedance of the to-be-tested battery at different frequencies are fitted to obtain the electrical data and the concentration of the electrochemical polarization and the concentration polarization, and the polarization time of the electrochemical polarization and the polarization time of the concentration polarization.

[0102] According to the polarization time of the electrochemical polarization and the polarization time of the concentration polarization, the polarization time constant of the to-be-tested battery is determined.

[0103] The equivalent circuit model (ECM) can refer to a circuit model constructed by combining a series of basic circuit elements (such as resistance R, capacitance C, Warburg element, etc.) according to the impedance response characteristics of an electrochemical system, which is used to simulate and characterize the physical behavior of different electrochemical processes inside the battery.

[0104] Figure 2b The model schematic diagram of the equivalent circuit model provided for the embodiment of the present application is shown in Figure 2b The equivalent circuit model can include electrochemical polarization, concentration polarization, and ohmic polarization. The electrochemical polarization can include a resistor Rep and a capacitor Cep in parallel, and the corresponding polarization time is The concentration polarization can include a resistor Rcp and a capacitor Ccp in parallel, and the corresponding polarization time is The ohmic polarization includes an ohmic resistor .

[0105] The real part and the imaginary part of the impedance spectrum at different frequencies are fitted by using the equivalent circuit model, and the parameter values of each electrical element in the model are continuously adjusted by using the least square method and other optimization algorithms, so that the theoretical impedance curve calculated by the model is as consistent as possible with the experimental data. The best fitting parameter result is finally output, so that the specific parameter values of the electrical elements such as resistance, capacitance, and inductance (including , Rep, Cep, Rcp, Ccp) are obtained.

[0106] After determining and , compare and , and take the larger polarization time as the polarization time constant .

[0107] By fitting the real and imaginary parts of the impedance of the battery at different frequencies based on an equivalent circuit model, key electrical parameters related to electrochemical polarization and concentration polarization can be effectively separated and extracted, and the respective polarization time constants can be further calculated. These polarization time constants reflect the response speed and time scale characteristics of different polarization processes inside the battery, thereby enabling fine modeling and analysis of the dynamic behavior of the battery and determination of the polarization time constants.

[0108] In the embodiments of the present application, the polarization time constant of the battery under test is determined according to the real and imaginary parts of the impedance of the battery under test, comprising:

[0109] The real and imaginary parts of the impedance of the battery under test at different frequencies are subjected to relaxation time distribution processing to obtain time constants corresponding to different relaxation times;

[0110] The polarization time constant of the battery under test is determined according to the time constants corresponding to different relaxation times.

[0111] The distribution of relaxation times (DRT) can refer to an analysis method based on electrochemical impedance spectroscopy (EIS) data, which is used to identify and separate the relaxation times corresponding to multiple dynamic processes inside the battery. By mathematical inversion technique, the frequency domain impedance data is converted into a distribution function with relaxation time as the independent variable, thereby revealing multiple polarization processes and their corresponding characteristic time constants existing in the system.

[0112] The time constant corresponding to different relaxation times can represent each peak-shaped distribution corresponding to the time constant, wherein each peak-shaped distribution can represent a specific physical or electrochemical process.

[0113] Figure 2c The relaxation time decomposition diagram provided by the embodiments of the present application is shown in FIG. 1, wherein the real and imaginary parts of the impedance spectrum at different frequencies are subjected to relaxation time distribution (DRT) data analysis to obtain time constants corresponding to different relaxation time peaks. Figure 2c Finally, the largest time constant among the time constants is selected as the polarization time constant .

[0114] ​By performing relaxation time distribution (DRT) processing on the real and imaginary parts of the impedance of the battery under test at different frequencies, the characteristic time constants corresponding to multiple relaxation processes in the system can be identified without relying on a model, thereby accurately extracting the polarization time constants related to electrochemical polarization and concentration polarization. The time scale characteristics of different kinetic processes inside the battery are effectively revealed, providing key evidence for the quantitative analysis of polarization behavior and the accurate modeling of battery dynamic response characteristics, and improving the accuracy of polarization time constant determination.

[0115] In the embodiments of the present application, when the vehicle of the battery under test satisfies at least one preset condition, the real and imaginary parts of the impedance of the battery under test are obtained.

[0116] The preset conditions include:

[0117] The timer of the vehicle reaches a set time;

[0118] The vehicle is in an unlocked state;

[0119] The door of the vehicle is in an open state.

[0120] When the vehicle satisfies at least one preset condition (such as the timer reaching a set time, the vehicle being in an unlocked state, or the door being in an open state), the collection of the real and imaginary parts of the battery impedance is triggered. In this way, it can be ensured that the vehicle is in a non-driving state or a time point when the user may operate, so that the information of the battery under test can be obtained under relatively stable, safe and convenient working conditions, thereby improving the accuracy and feasibility of the measurement. In addition, it also helps to realize automatic monitoring, so that the battery state evaluation can be completed at the right time without manual intervention, which is beneficial to the real-time monitoring of the battery health status by the battery management system (BMS).

[0121] After obtaining the polarization time constant of the battery under test, in order to determine the polarization voltage of the battery under test at the static time, the initial polarization voltage of the battery under test needs to be determined, that is, in the embodiments of the present application, the polarization voltage of the battery under test at the static time is determined according to the polarization decay degree of the battery under test, including:

[0122] The initial polarization voltage of the battery under test is obtained, and the initial polarization voltage is determined according to the decay change degree and open-circuit change voltage corresponding to different static times of the battery under test;

[0123] The polarization voltage of the battery under test at the static time is determined according to the polarization decay degree and the initial polarization voltage of the battery under test.

[0124] The initial polarization voltage can refer to the additional voltage offset generated inside the battery due to the electrochemical polarization effect (such as activation polarization, concentration polarization, etc.) when the battery just stops charging and discharging and enters the static state.

[0125] Since the decay process of the polarization voltage usually follows a known dynamic model (e.g. an exponential decay model), according to which the polarization voltage decays exponentially with time, the decay rate is determined by the polarization time constant of the battery. Therefore, given the polarization decay degree and open circuit voltage change at multiple time points, the polarization voltage value at the beginning of the rest can be solved inversely by fitting or recursive method.

[0126] In the embodiments of the present application, the method further comprises:

[0127] determining a previous open circuit voltage and a previous polarization decay degree of the battery at a previous rest time corresponding to the previous rest time, the previous rest time being a time point before the rest time and satisfying a rest time difference requirement;

[0128] determining an open circuit change voltage according to the previous open circuit voltage and the open circuit voltage;

[0129] determining a decay change degree according to the previous polarization decay degree and the polarization decay degree;

[0130] determining the initial polarization voltage according to the open circuit change voltage and the decay change degree.

[0131] The previous rest time refers to a time point before the current rest time, and satisfies a certain time difference requirement with the current rest time, for example, when the rest time is 30 minutes, the previous rest time can be 29 minutes. It should be noted that, in order to ensure accuracy, the rest time difference requirement between the previous rest time and the rest time can be less than 1 minute.

[0132] The previous open circuit voltage is the battery terminal voltage measured at the previous rest time, and the previous polarization decay degree is the degree of decay of the internal polarization effect of the battery at the time point;

[0133] The open circuit change voltage refers to the difference between the open circuit voltages corresponding to the current rest time and the previous rest time, which reflects the change amount of the voltage with time. The decay change degree refers to the difference between the current polarization decay degree and the previous polarization decay degree, which can represent the dynamic change of the polarization recovery process.

[0134] Therefore, the initial polarization voltage can satisfy:

[0135] ;

[0136] wherein, is the previous open circuit voltage measured at the previous rest time t1; is the open circuit voltage measured at the rest time t2; is the polarization decay degree measured at the rest time t2; is the polarization decay degree measured at the last standing time t1.

[0137] Therefore, by acquiring the open-circuit voltage and the corresponding polarization decay degree of the battery to be measured at different standing times, combining the information corresponding to the last standing time, dynamically calculating the initial polarization voltage of the battery at the initial standing time, and further deducing the polarization voltage at the current standing time point, the voltage deviation caused by the polarization effect can be accurately identified and compensated in the case that the battery has not completely entered the steady-state response and the standing time is insufficient, thereby improving the open-circuit voltage measurement accuracy and the accuracy of subsequent state of charge estimation. The method breaks the dependence on long-time standing of the traditional method, improves the real-time performance and robustness of battery state estimation, and is particularly suitable for battery management requirements under complex working conditions in electric vehicles and energy storage systems.

[0138] When the standing time of the battery to be measured indicates that the battery to be measured has not entered the steady-state response, in addition to the influence of the polarization effect, the battery internal temperature of the battery to be measured (i.e., temperature imbalance) will also affect the accuracy of the open-circuit voltage measurement. Therefore, in the embodiments of the present application, the method further includes:

[0139] acquiring the battery internal temperature of the battery to be measured and the temperature correction coefficient of the battery internal temperature; the battery internal temperature is determined according to the real part and the imaginary part of the impedance of the battery to be measured, and the amplitude and the phase determined according to the real part and the imaginary part of the impedance of the battery to be measured;

[0140] correcting the corrected open-circuit voltage according to the temperature correction coefficient corresponding to the battery internal temperature to obtain a target open-circuit voltage.

[0141] wherein the battery internal temperature satisfies: ;

[0142] wherein, is the real part; is the imaginary part; Z is the amplitude determined according to the real part and the imaginary part; is the phase determined according to the real part and the imaginary part.

[0143] In the embodiments of the present application, the amplitude satisfies: ;

[0144] the phase satisfies: .

[0145] The temperature correction coefficient corresponding to the battery internal temperature can refer to a compensation parameter for characterizing the influence of temperature change on the electrochemical performance of the battery, which can reflect the trend of key parameters such as battery impedance, open-circuit voltage or capacity changing with temperature. The coefficient can be used to standardize the battery data measured under different temperature conditions, eliminate the measurement deviation caused by temperature fluctuation, and thus improve the accuracy and consistency of battery state estimation. According to different temperatures, the corresponding SOC curve can be selected. After the battery design is completed, the curve is tested. The curve is further processed into a temperature correction coefficient KT, that is , according to the corresponding SOC, the OCV-SOC curve at 25℃ is unified. For example, Figure 2d is the SOC and OCV diagram provided by the embodiment of the present application under different temperatures. As shown in Figure 2d , if the current temperature is 50℃, the measured , by multiplying the coefficient KT, the OCV25℃ (target open-circuit voltage) is obtained. In addition, the corresponding SOC can be obtained by using the OCV-SOC query at 25℃.

[0146] Therefore, when the battery internal temperature is determined, the temperature compensation adjustment of the corrected open-circuit voltage can be performed through the preset relationship between the battery internal temperature and the temperature correction coefficient. Therefore, the temperature influence caused by environmental or working condition changes can be eliminated, the accuracy of battery state evaluation is improved, the battery management system can more truly and reliably reflect the actual performance and health status of the battery, and thus the use efficiency and safety of the battery are optimized.

[0147] In the embodiment of the present application, the method further comprises:

[0148] When the standing time of the battery to be measured indicates that the battery to be measured enters a steady-state response, and the standing time of the battery to be measured does not exceed the preset standing time, the battery internal temperature of the battery to be measured is obtained, and the temperature correction coefficient corresponding to the battery internal temperature is obtained.

[0149] According to the temperature correction coefficient corresponding to the battery internal temperature, the open-circuit voltage of the battery to be measured obtained at the standing time is corrected to obtain a target open-circuit voltage.

[0150] In the embodiment of the present application, the preset standing time can refer to the time for the internal temperature of the battery to be measured to balance. The standing time of the battery to be measured indicates that the battery to be measured enters a steady-state response, and the standing time of the battery to be measured does not exceed the preset standing time, which indicates that the polarization effect in the battery to be measured is eliminated, but the internal temperature has not balanced. At the current time, the polarization voltage does not need to be obtained, and only the open-circuit voltage of the battery to be measured obtained at the standing time needs to be corrected by the temperature correction coefficient.

[0151] In some embodiments, when the rest time of the battery to be tested exceeds the preset rest time, the internal polarization effect of the battery to be tested is eliminated, and the temperature is also balanced. At this time, the open circuit voltage can be directly measured. Thus, by acquiring the internal temperature and the corresponding temperature correction coefficient of the battery to be tested under the condition that the rest time of the battery to be tested meets the entering steady-state response and does not exceed the preset rest time, and correcting the open circuit voltage collected during the rest period according to the temperature correction coefficient, a more accurate target open circuit voltage is obtained. Thus, the current state of the battery is fully considered, the fine voltage compensation based on the actual operating conditions of the battery is realized, the accuracy of the battery state recognition is improved, and the classification management of the battery under different working conditions is facilitated, thereby providing reliable data support for the battery health state evaluation and use strategy optimization.

[0152] Figure 3 Another flowchart of a battery open circuit voltage correction method provided in the present application is shown in FIG. 4. The method comprises the following steps. Figure 3

[0153] S301, vehicle parking: timing starts;

[0154] S302, judging whether the vehicle is unlocked, whether the vehicle door is opened, and whether the period time reaches the set time.

[0155] The timing starts after the vehicle is parked and locked. The function triggering module starts the OCV voltage UL detection function according to the set condition. The set triggering conditions include: 1, the timer reaches the set time, such as 2h; 2, the vehicle is unlocked; 3, the vehicle door is opened.

[0156] S303, electrochemical impedance measurement.

[0157] The electrochemical impedance measurement is performed by EIS test. When the EIS test starts, the BECM sends a command to the excitation source to perform pulse current excitation. The BECM sends a command to the CMC (battery monitoring controller) to perform EIS test. The pulse current generated by the excitation source acts on the battery. The battery forms a response voltage under the action of the excitation current. The CMC measures the pulse current and the response voltage, and performs discrete Fourier transform (DFT) to obtain the real part (Re) and the imaginary part (Im) of the impedance of each battery, and sends them to the BECM. The BECM further processes to obtain the amplitude and phase under the excitation frequency, and obtains the internal temperature of the battery based on the EIS data.

[0158] S304, polarization state calculation module.

[0159] When the current polarization state of the battery is obtained:

[0160] ​​​The equivalent circuit model can be used to fit the real and imaginary parts of the impedance spectrum at different frequencies to obtain specific parameter values of the electrical elements such as resistance, capacitance, and inductance , Rep, Cep, Rcp, Ccp, and the like. The equivalent circuit model can be a second-order equivalent circuit model.

[0161] When the current IL in the second-order equivalent circuit model is equal to 0, the voltage UL across the battery is measured, and the open-circuit voltage at this time can be calculated (the open-circuit voltage is the open-circuit voltage when the resting time of the battery to be measured exceeds the preset resting time).

[0162] Open-circuit voltage satisfies:

[0163] ;

[0164] ;

[0165] ;

[0166] wherein, is the terminal voltage of the electrochemical polarization, is the terminal voltage of the concentration polarization, is the rate of change of the terminal voltage of the electrochemical polarization, is the rate of change of the terminal voltage of the concentration polarization.

[0167] The equivalent circuit model can also calculate the time constant of the polarization state:

[0168] ;

[0169] wherein, in the formula, cp represents the concentration polarization, and ep represents the electrochemical polarization.

[0170] After obtaining and , if is greater than , then is taken as the system time constant, if is greater than , then is taken as the system time constant, and if is equal to , then or is taken as the system time constant.

[0171] Alternatively, the real and imaginary parts of the impedance spectrum at different frequencies are subjected to relaxation time distribution (DRT) data analysis to obtain the time , , …, And select the largest time constant as the polarization time constant .

[0172] S305, continuous 2 times voltage sampling.

[0173] Wherein, BMS continuous collection 2 times battery voltage. In the condition of battery static, can obtain the open circuit voltage under the current temperature.

[0174] Wherein, open circuit voltage can be according to:

[0175] ;

[0176] ;

[0177] ;

[0178] ;

[0179] Wherein, time constant Is obtained by the above polarization module.

[0180] S305, multi-stage correction strategy module: 0≤static time<3*time constant: OCV=UL*temperature correction*polarization state correction; 3*time constant≤static time<2h: OCV=UL*temperature correction; 2h≤static time: OCV=UL.

[0181] Wherein, according to Can be determined:

[0182] 1 time constant: ;

[0183] 2 time constants: ;

[0184] 3 time constants: ;

[0185] 4 time constants: ;

[0186] 5 time constants: ;

[0187] 6 time constants: .

[0188] Wherein, RC is the time constant, the constant is equal to the polarization time constant .

[0189] It can be determined that the voltage at the end of the capacitor 2 representing the polarization degree gradually decays over time, and when more than 3 time constants are exceeded, the polarization state is only 0.050 of the initial state, and it can be considered that the battery has reached equilibrium. Therefore, the time of 3 time constants is used as a strategy dividing point.

[0190] Based on this, the multi-stage correction strategy can be:

[0191] When the standing time is < 1h, only consider temperature imbalance: , consider polarization and temperature imbalance:

[0192] .

[0193] ≤ standing time < 2h, only consider temperature imbalance:

[0194] .

[0195] 2h≤standing time, directly collect.

[0196] S306, according to the OCV, OCV-SOC lookup table is carried out to obtain the SOC.

[0197] Another battery open circuit voltage correction method provided by the embodiment of the application can realize timely correction of the SOC in the case that the battery cannot be placed for a long time; by adopting the multi-stage correction strategy and dynamically adjusting the time constant, the accuracy of the SOC estimation is effectively improved; at the same time, the method has strong flexibility and can adapt to various working scenes and environmental conditions; in addition, the method has cost effectiveness, and performance optimization can be realized without increasing system complexity, thereby reducing the overall implementation cost.

[0198] Figure 4 The structure diagram of the battery open circuit voltage correction device provided by the application is shown in FIG. 1, and the battery open circuit voltage correction device 40 provided by the embodiment of the application comprises: Figure 4

[0199] The determining module 401 is configured to determine the polarization voltage of the battery under test at the standing time according to the polarization decay degree of the battery under test when the standing time of the battery under test represents that the battery under test has not entered a steady state response; and the polarization decay degree of the battery under test is determined according to the standing time and the polarization time constant of the battery under test.

[0200] The obtaining module 402 is configured to correct the open circuit voltage of the battery under test obtained at the standing time according to the polarization voltage of the battery under test at the standing time, to obtain the corrected open circuit voltage of the battery under test.

[0201] In a possible implementation manner, the determining module 401 can be specifically configured to:

[0202] ​acquire an initial polarization voltage of the battery to be measured, the initial polarization voltage being determined according to a degree of attenuation change and an open-circuit change voltage corresponding to different standing times of the battery to be measured;

[0203] determine the polarization voltage of the battery to be measured at the standing time according to the degree of polarization attenuation and the initial polarization voltage of the battery to be measured.

[0204] In a possible implementation, the determining module 401 can be further specific to:

[0205] determine a previous open-circuit voltage and a previous degree of polarization attenuation of the battery to be measured corresponding to a previous standing time, the previous standing time being a time before the standing time and meeting a standing time difference requirement;

[0206] determine the open-circuit change voltage according to the previous open-circuit voltage and the open-circuit voltage;

[0207] determine the degree of attenuation change according to the previous degree of polarization attenuation and the degree of polarization attenuation;

[0208] determine the initial polarization voltage according to the open-circuit change voltage and the degree of attenuation change.

[0209] In a possible implementation, the determining module 401 can be further specific to:

[0210] determine degrees of polarization attenuation of the battery to be measured corresponding to different times;

[0211] determine a target degree of polarization attenuation and a time corresponding to the target degree of polarization attenuation according to a change of the degrees of polarization attenuation over time;

[0212] when the standing time of the battery to be measured is less than the time corresponding to the target degree of polarization attenuation, determine that the standing time of the battery to be measured represents that the battery to be measured has not entered a steady-state response.

[0213] In a possible implementation, the determining module 401 can be further specific to:

[0214] acquire a real part and an imaginary part of an impedance of the battery to be measured, the real part and the imaginary part of the impedance of the battery to be measured being obtained by performing a discrete Fourier transform on the pulse current and the response voltage, the response voltage being a voltage of the battery to be measured under the action of the pulse current;

[0215] determine a polarization time constant of the battery to be measured according to the real part and the imaginary part of the impedance of the battery to be measured.

[0216] In a possible implementation, the determining module 401 can be further specific to:

[0217] According to the equivalent circuit model corresponding to the to-be-tested battery, the real part and the imaginary part of the impedance of the to-be-tested battery at different frequencies are fitted to obtain the electrical data and the concentration polarization data of the electrochemical polarization and the polarization time of the electrochemical polarization and the concentration polarization in the equivalent circuit model;

[0218] According to the polarization time of the electrochemical polarization and the polarization time of the concentration polarization, the polarization time constant of the to-be-tested battery is determined.

[0219] In a possible implementation, the determining module 401 can be specifically configured to:

[0220] The real part and the imaginary part of the impedance of the to-be-tested battery at different frequencies are subjected to relaxation time distribution processing to obtain the time constant corresponding to different relaxation times;

[0221] According to the time constant corresponding to different relaxation times, the polarization time constant of the to-be-tested battery is determined.

[0222] In a possible implementation, the determining module 401 can be specifically configured to:

[0223] When the vehicle of the to-be-tested battery satisfies at least one preset condition, the real part and the imaginary part of the impedance of the to-be-tested battery are obtained.

[0224] The preset condition includes:

[0225] The timer of the vehicle reaches a set time;

[0226] The vehicle is in an unlocked state;

[0227] The door of the vehicle is in an open state.

[0228] In a possible implementation, the obtaining module 402 can be specifically configured to:

[0229] The internal temperature of the to-be-tested battery and the temperature correction coefficient of the internal temperature of the to-be-tested battery are obtained, the internal temperature of the to-be-tested battery being determined according to the real part and the imaginary part of the impedance of the to-be-tested battery and the amplitude and the phase determined according to the real part and the imaginary part of the impedance of the to-be-tested battery;

[0230] The open-circuit voltage is corrected according to the temperature correction coefficient corresponding to the internal temperature of the to-be-tested battery to obtain the target open-circuit voltage.

[0231] Alternatively,

[0232] In a possible implementation, the obtaining module 402 can be specifically configured to:

[0233] When the standby time of the battery to be measured represents that the battery to be measured enters a steady-state response, and the standby time of the battery to be measured does not exceed the preset standby time, the battery internal temperature of the battery to be measured is acquired, and a temperature correction coefficient corresponding to the battery internal temperature is acquired;

[0234] According to the temperature correction coefficient corresponding to the battery internal temperature, the open-circuit voltage of the battery to be measured acquired at the standby time is corrected to obtain a target open-circuit voltage.

[0235] The battery open-circuit voltage correction device provided in the embodiment can execute the method provided in the method embodiment, and has similar implementation principles and technical effects, which will not be described here.

[0236] Figure 5 A structural schematic diagram of a vehicle is provided in the present application. As shown in the figure, Figure 5 The vehicle 50 provided in the embodiment includes at least one processor 501 and a memory 502. Optionally, the device 50 further includes a communication component 503. The processor 501, the memory 502 and the communication component 503 are connected through a bus 504.

[0237] In the specific implementation process, the at least one processor 501 executes the computer execution instructions stored in the memory 502, so that the at least one processor 501 executes the method described above.

[0238] The specific implementation process of the processor 501 can refer to the method embodiment described above, which has similar implementation principles and technical effects, and will not be described here.

[0239] In the above embodiment, it should be understood that the processor can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), etc. The general-purpose processor can be a microprocessor, or the processor can also be any conventional processor, etc. The steps of the method disclosed in the application can be directly embodied as execution completed by a hardware processor, or executed by a combination of hardware and software modules in the processor.

[0240] The memory can include a random access memory (RAM), and can also include a non-volatile memory (NVM), for example, at least one disk memory.

[0241] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, the bus in the drawings of the present application does not limit to only one bus or one type of bus.

[0242] The present application also provides a computer program product, comprising a computer program, which, when executed by a processor, implements the method described above.

[0243] The present application also provides a computer readable storage medium, which stores computer execution instructions, and when a processor executes the computer execution instructions, the method described above is implemented.

[0244] The readable storage medium described above can be realized by any type of volatile or non-volatile storage device or their combination, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general or special purpose computer.

[0245] An exemplary readable storage medium is coupled to the processor, so that the processor can read information from the readable storage medium, and can write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist as discrete components in the device.

[0246] The division of units is only a logical functional division, and in actual implementation, there can be another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0247] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, i.e., may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0248] In addition, each functional unit in various embodiments of the application can be integrated into one processing unit, or each unit can exist physically, or two or more units can be integrated into one unit.

[0249] If the function is realized in the form of a software function 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 solutions of the application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the various embodiment methods of the application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0250] Those skilled in the art can understand that all or part of the steps of the above-mentioned method embodiments can be completed by program instruction related hardware. The aforementioned program can be stored in a computer readable storage medium. The program executes to perform the steps of the above-mentioned method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, and various media that can store program codes.

[0251] Finally, it should be noted that those skilled in the art, after considering the specification and practicing the application disclosed herein, will easily think of other embodiments of the application. The application is intended to cover any variations, uses, or adaptations of the application that follow the general principles of the application and include common knowledge or conventional techniques in the art that are not disclosed by the application, and is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the application is only limited by the appended claims.

Claims

1. A method for correcting the open-circuit voltage of a battery, characterized in that, The method includes: When the resting time of the battery under test indicates that the battery under test has not entered a steady-state response, the polarization voltage of the battery under test during the resting time is determined according to the degree of polarization decay of the battery under test; the degree of polarization decay of the battery under test is determined according to the resting time and polarization time constant of the battery under test. Based on the polarization voltage of the battery under test during the resting time, the open-circuit voltage of the battery under test obtained during the resting time is corrected to obtain the corrected open-circuit voltage of the battery under test.

2. The method according to claim 1, characterized in that, Determining the polarization voltage of the battery under test during the resting time based on the degree of polarization decay includes: The initial polarization voltage of the battery under test is obtained, and the initial polarization voltage is determined based on the degree of decay change and open circuit change voltage of the battery under test at different resting times. The polarization voltage of the battery under test during the resting time is determined based on the degree of polarization decay and the initial polarization voltage.

3. The method according to claim 2, characterized in that, The method further includes: Determine the previous open-circuit voltage and the previous polarization attenuation degree of the battery under test at the previous resting time; the previous resting time is the time before the resting time that meets the resting time difference requirement; The open-circuit change voltage is determined based on the previous open-circuit voltage and the open-circuit voltage. The degree of attenuation change is determined based on the previous polarization attenuation degree and the polarization attenuation degree. The initial polarization voltage is determined based on the open-circuit voltage variation and the degree of attenuation variation.

4. The method according to claim 1, characterized in that, The method further includes: Determine the degree of polarization decay of the battery under test at different times; Based on the change of the polarization attenuation degree over time, determine the target polarization attenuation degree and the time corresponding to the target polarization attenuation degree; When the resting time of the battery under test is less than the time corresponding to the target polarization decay degree, the resting time of the battery under test is determined to indicate that the battery under test has not entered a steady-state response.

5. The method according to any one of claims 1 to 4, characterized in that, The method further includes: The real and imaginary parts of the impedance of the battery under test are obtained. The real and imaginary parts of the impedance of the battery under test are obtained by performing a discrete Fourier transform on the pulse current and the response voltage. The response voltage is the voltage of the battery under test under the action of the pulse current. The polarization time constant of the battery under test is determined based on the real and imaginary parts of the impedance of the battery under test.

6. The method according to claim 5, characterized in that, The step of determining the polarization time constant of the battery under test based on the real and imaginary parts of the impedance of the battery under test includes: Based on the equivalent circuit model corresponding to the battery under test, the real and imaginary parts of the impedance of the battery under test at different frequencies are fitted to obtain the electrical data of electrochemical polarization and concentration polarization in the equivalent circuit model, as well as the polarization time of electrochemical polarization and the polarization time of concentration polarization. The polarization time constant of the battery under test is determined based on the polarization time of the electrochemical polarization and the polarization time of the concentration polarization.

7. The method according to claim 5, characterized in that, The step of determining the polarization time constant of the battery under test based on the real and imaginary parts of the impedance of the battery under test includes: The real and imaginary parts of the impedance of the battery under test at different frequencies are processed by relaxation time distribution to obtain the time constants corresponding to different relaxation times; The polarization time constant of the battery under test is determined based on the time constants corresponding to the different relaxation times.

8. The method according to claim 5, characterized in that, When the vehicle carrying the battery under test meets at least one preset condition, the real and imaginary parts of the impedance of the battery under test are obtained. The preset conditions include: The vehicle's timer reaches the set time; The vehicle is in an unlocked state; The vehicle's doors are open.

9. The method according to any one of claims 1 to 4, characterized in that, The method further includes: The internal temperature of the battery under test and the temperature correction coefficient of the internal temperature of the battery are obtained; the internal temperature of the battery is determined based on the real and imaginary parts of the impedance of the battery under test, and the amplitude and phase are determined based on the real and imaginary parts of the impedance of the battery under test. The corrected open-circuit voltage is corrected according to the temperature correction coefficient corresponding to the internal temperature of the battery to obtain the target open-circuit voltage; or, The method further includes: When the resting time of the battery under test indicates that the battery under test has entered a steady-state response, and the resting time of the battery under test has not exceeded the preset resting time, the internal temperature of the battery under test and the temperature correction coefficient corresponding to the internal temperature of the battery are obtained. Based on the temperature correction coefficient corresponding to the internal temperature of the battery, the open-circuit voltage of the battery under test obtained during the resting time is corrected to obtain the target open-circuit voltage.

10. A battery open-circuit voltage correction device, characterized in that, include: The determination module is used to determine the polarization voltage of the battery under test during the resting time, based on the degree of polarization decay of the battery under test, when the resting time of the battery under test indicates that the battery under test has not entered a steady-state response; the degree of polarization decay of the battery under test is determined based on the resting time and polarization time constant of the battery under test. The module is used to correct the open-circuit voltage of the battery under test obtained during the resting time based on the polarization voltage of the battery under test during the resting time, so as to obtain the corrected open-circuit voltage of the battery under test.

11. A vehicle, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in any one of claims 1-9.

12. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-9.

13. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method described in any one of claims 1-9.

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