Hysteresis coefficient calibration method for battery and electronic equipment

Abstract

The invention provides a hysteresis coefficient calibration method for a battery, and the method comprises the following steps: discharging the battery from a first initial charge state to a first target charge state through a plurality of unequal discharge currents, and measuring the open-circuit voltage, corresponding to the first target charge state, of the battery after standing for a preset period of time; the measured open-circuit voltage is compared with a reference open-circuit voltage determined according to a reference OCV-SOC corresponding relation to determine a hysteresis coefficient, and the hysteresis coefficient represents the deviation degree of the OCV-SOC corresponding relation of the battery relative to the reference OCV-SOC corresponding relation caused by the hysteresis effect; and determining a corresponding relationship between the discharge currents and the hysteresis coefficients based on the plurality of discharge currents and the corresponding hysteresis coefficients. The present application also proposes a state of charge determination method for a battery, a computer program product, an electronic device, and a vehicle. According to the invention, the state of charge of the battery can be determined more accurately.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of batteries, and in particular to a hysteresis coefficient calibration method for a battery, a state of charge determination method for a battery, a computer program product, an electronic device and a vehicle. BACKGROUND

[0002] With the development of energy storage technology, in recent years, batteries have been widely used in various fields, especially in the field of vehicles. In use, the state of charge (SOC) of the battery as a key parameter reflecting the remaining capacity directly affects the running performance, safety and user experience. Therefore, it is crucial to accurately and reliably estimate the SOC.

[0003] Generally, the SOC can be estimated by detecting the open circuit voltage (OCV) of the battery and mapping calculation by means of the pre-calibrated OCV-SOC curve. This method is based on the characteristic that there is a correlation between the OCV and the SOC of the battery in a static state. However, the accuracy of this method is limited by various factors, especially the inherent hysteresis effect of the battery. The hysteresis effect causes the OCV to differ between charging and discharging processes at the same SOC. The battery needs to go through complex and variable working conditions in actual application, so that its actual OCV response often deviates significantly from the static OCV-SOC curve under ideal calibration environment.

[0004] Therefore, although the prior art can achieve the estimation of the SOC to some extent, it still has obvious deficiencies in accuracy. SUMMARY

[0005] The purpose of the present application is to provide an improved hysteresis coefficient calibration method for a battery, a state of charge determination method for a battery, and a corresponding computer program product, electronic device and vehicle, in order to at least partially overcome the deficiencies of the prior art.

[0006] According to a first aspect of the present application, a hysteresis coefficient calibration method for a battery is provided, wherein the hysteresis coefficient calibration method comprises the following steps: S110, discharging the battery from a first initial state of charge to a first target state of charge with a plurality of unequal discharging currents respectively, and measuring the open circuit voltage of the battery corresponding to the first target state of charge after a predetermined period of rest; S120, comparing the measured open circuit voltage with a reference open circuit voltage determined according to a reference OCV-SOC correspondence relationship, to determine a hysteresis coefficient, the hysteresis coefficient representing the degree of deviation of the OCV-SOC correspondence relationship of the battery caused by the hysteresis effect from the reference OCV-SOC correspondence relationship; and S130, determining a correspondence relationship between discharging current and hysteresis coefficient based on the plurality of discharging currents and the corresponding hysteresis coefficients.

[0007] Thus, a corresponding relationship between the discharge current and the hysteresis coefficient can be obtained, which can be used to determine the hysteresis coefficient corresponding to the discharge current of the battery during use of the battery. With the hysteresis coefficient thus determined, the state of charge of the battery can be determined more accurately.

[0008] In one example embodiment, the hysteresis coefficient is set to represent a degree of deviation of the actual OCV-SOC corresponding relationship of the battery from a reference average OCV-SOC corresponding relationship, wherein the reference average OCV-SOC corresponding relationship represents a corresponding relationship between the state of charge and an average value of open circuit voltage corresponding to the state of charge according to a reference OCV-SOC charging corresponding relationship and a reference OCV-SOC discharging corresponding relationship respectively, a sign of the hysteresis coefficient is used to represent a deviation direction relative to the reference average OCV-SOC corresponding relationship, and an absolute value of the hysteresis coefficient is used to represent a degree of deviation relative to the reference average OCV-SOC corresponding relationship, wherein the greater the absolute value of the hysteresis coefficient, the greater the degree of deviation relative to the reference average OCV-SOC corresponding relationship.

[0009] With the hysteresis coefficient thus set, the influence of the hysteresis effect on the battery during actual use can be better reflected.

[0010] In one example embodiment, in step S130, a negative correlation corresponding relationship between the discharge current and the absolute value of the hysteresis coefficient is determined.

[0011] The inventor has found that for a battery undergoing a discharging process, the smaller the discharge current, the greater the absolute value of the hysteresis coefficient. Therefore, a negative correlation corresponding relationship between the discharge current and the absolute value of the hysteresis coefficient can be determined. This negative correlation corresponding relationship can be used to accurately determine the hysteresis coefficient adapted to the actual use of the battery.

[0012] In one example embodiment, in step S130, a logarithmic fitting is performed on the discharge current and the hysteresis coefficient to determine the following logarithmic relationship:

[0013] λ = a * ln (I_D) + b

[0014] wherein λ represents the hysteresis coefficient, I_D represents the discharge current, and a and b are parameters determined by fitting.

[0015] In one example embodiment, in step S120, the hysteresis coefficient is determined by:

[0016] λ = 2 * (OCV_M - (OCV_C + OCV_D) / 2) / (OCV_C - OCV_D)

[0017] wherein λ represents a hysteresis coefficient, OCV_M represents a measured open circuit voltage, OCV_C represents a charging reference open circuit voltage corresponding to the first target state of charge according to the reference OCV-SOC charging correspondence, and OCV_D represents a discharging reference open circuit voltage corresponding to the first target state of charge according to the reference OCV-SOC discharging correspondence.

[0018] In one example embodiment, step S110 is performed for a plurality of different first target states of charge. In step S130, for each discharging current, an average hysteresis coefficient of the hysteresis coefficients corresponding to the plurality of different first target states of charge is calculated, to determine a correspondence between discharging current and hysteresis coefficient based on each discharging current and the average hysteresis coefficient. This helps to more accurately determine the correspondence between discharging current and hysteresis coefficient.

[0019] In one example embodiment, in step S110, the battery is discharged from a full state of charge to the first target state of charge at a discharging current of 0.02C, 0.1C, 0.3C, 0.5C and 1C respectively at a temperature condition of 25°C, and then rested for 8 hours.

[0020] According to a second aspect of the present application, there is provided a state of charge determination method for a battery, wherein the state of charge determination method comprises the following steps: S210, obtaining an actual open circuit voltage of the battery and an average discharging current of the battery during discharging; S220, determining a hysteresis coefficient corresponding to the average discharging current according to a correspondence between discharging current and hysteresis coefficient, the hysteresis coefficient representing a degree of deviation of an OCV-SOC correspondence of the battery from a reference OCV-SOC correspondence due to a hysteresis effect; and S230, determining a state of charge of the battery according to the hysteresis coefficient and the reference OCV-SOC correspondence based on the actual open circuit voltage of the battery.

[0021] As described above, the inventors have found that the magnitude of the discharging current will affect the hysteresis coefficient. Using the correspondence between discharging current and hysteresis coefficient, the hysteresis coefficient corresponding to the actual discharging current can be determined. On this basis, the SOC can be more accurately determined from the OCV.

[0022] The hysteresis coefficient may, for example, be set in the manner described above.

[0023] In one example embodiment, the correspondence between discharging current and hysteresis coefficient comprises a negative correlation correspondence between discharging current and absolute value of the hysteresis coefficient.

[0024] As described above, the inventors found that for a battery undergoing a discharging process, the smaller the discharging current, the larger the absolute value of the hysteresis coefficient. Therefore, the negative correlation between the discharging current and the absolute value of the hysteresis coefficient can be utilized to more accurately determine the hysteresis coefficient that fits the actual usage of the battery.

[0025] In one example embodiment, the correspondence between the discharging current and the hysteresis coefficient is determined by a hysteresis coefficient calibration method for a battery according to example embodiments of the present application.

[0026] In one example embodiment, the state of charge determination method comprises determining the correspondence between the discharging current and the hysteresis coefficient by a hysteresis coefficient calibration method for a battery according to example embodiments of the present application.

[0027] According to a third aspect of the present application, there is provided a hysteresis coefficient calibration method for a battery, wherein the hysteresis coefficient calibration method comprises the following steps: S310, after discharging the battery from a second initial state of charge to a second target state of charge at a plurality of discharging currents respectively, charging the battery to reach a predetermined state of charge increment at a predetermined charging current; S320, measuring the open circuit voltage of the battery at a plurality of different state of charge increments during the charging process of step S310, and comparing the measured open circuit voltage with a reference open circuit voltage determined according to a reference OCV-SOC correspondence to determine a hysteresis coefficient, the hysteresis coefficient being used to represent the degree of deviation of the OCV-SOC correspondence of the battery caused by the hysteresis effect from the reference OCV-SOC correspondence; and S330, based on the state of charge increment and the corresponding hysteresis coefficient, determining a correspondence between the hysteresis coefficient and a growth factor of the hysteresis coefficient in the next unit state of charge interval, the growth factor representing the increment or amplitude of the hysteresis coefficient.

[0028] Thus, the correspondence between the hysteresis coefficient and its growth factor during the charging process after discharging can be obtained, which can be used to determine the hysteresis coefficient of the battery during the usage of the battery. By the hysteresis coefficient thus determined, the state of charge of the battery can be more accurately determined.

[0029] The inventors found that the growth factor of the hysteresis coefficient during the charging process after discharging has a high correlation with the hysteresis coefficient itself, and has a low correlation (even no correlation) with other factors (e.g. the discharging current of the discharging process, the charging current of the charging process, or the SOC, etc.). By the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval, the growth factor and thus the current hysteresis coefficient can be determined. Based on the hysteresis coefficient thus determined, the SOC can be more accurately determined according to the OCV.

[0030] The hysteresis coefficient can be set in the manner described above, for example.

[0031] In one exemplary embodiment, the predetermined state of charge increment is at least 6%.

[0032] In an exemplary embodiment, in step S310, after discharging the battery to 15% state of charge with discharge currents of 0.1C, 0.5C, and 1C respectively, the battery is charged with a charging current of 0.1C until the state of charge increment reaches 6% or more.

[0033] According to a fourth aspect of this application, a method for determining the state of charge (SOC) of a battery is provided, wherein the battery undergoes a charging process after a discharging process. The SOC determination method includes the following steps: S410, obtaining an initial hysteresis coefficient of the battery at the start of the charging process; and S420, during the charging process, the current hysteresis coefficient of the battery is an updated hysteresis coefficient obtained by increasing the previous hysteresis coefficient of the battery within a unit SOC interval by a growth factor, wherein the growth factor represents the increment or increase of the hysteresis coefficient, and the growth factor is determined using the previous hysteresis coefficient based on the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient within the next unit SOC interval.

[0034] As mentioned above, the inventors discovered that during the charging process after discharge, the growth factor of the hysteresis coefficient is highly correlated with the hysteresis coefficient itself, but less correlated with other factors (e.g., the discharge current during discharge, the charging current during charging, or the State of Charge (SOC)). By utilizing the correspondence between the hysteresis coefficient and its growth factor within the next unit state of charge interval, the growth factor can be determined, and thus the current hysteresis coefficient can be determined. Based on the hysteresis coefficient determined in this way, the State of Charge (SOC) can be determined more accurately according to the OCV (Optical Characteristic Value).

[0035] The hysteresis coefficient can be set in the manner described above.

[0036] In one exemplary embodiment, the growth factor is determined solely based on the previous hysteresis coefficient. The growth factor of the current hysteresis coefficient is only related to the previous hysteresis coefficient and is independent of factors such as the charging current during charging, the discharging current during discharging, and / or the state of charge (SOC). Furthermore, in practice, the hysteresis coefficient can be determined explicitly and accurately as the basis for determining the growth factor. In contrast, factors such as charging current, discharging current, or SOC are often difficult to determine accurately and explicitly. Therefore, determining the growth factor solely based on the previous hysteresis coefficient also helps to avoid introducing errors.

[0037] In one exemplary embodiment, the initial hysteresis coefficient is determined based on the average discharge current of the battery during the discharge process.

[0038] In one exemplary embodiment, the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval is determined by a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of the present application.

[0039] In one exemplary embodiment, the state of charge determination method includes using a hysteresis coefficient calibration method for batteries according to an exemplary embodiment of the present application to determine the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval.

[0040] In an exemplary embodiment, the state of charge determination method further includes the following steps: S430, determining whether the state of charge increment of the battery during charging exceeds a state of charge increment threshold; if the state of charge increment of the battery during charging is within the state of charge increment threshold, performing step S420; if the state of charge increment of the battery during charging exceeds the state of charge increment threshold, performing step S440, wherein the state of charge increment threshold is optionally set to 6%; and S440, setting the hysteresis coefficient to a predetermined value, or the hysteresis coefficient may remain unchanged.

[0041] According to a fifth aspect of this application, a computer program product is provided, comprising computer program instructions, wherein, when executed by one or more processors, the computer program instructions enable the one or more processors to perform a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application or a state of charge determination method according to an exemplary embodiment of this application.

[0042] According to a sixth aspect of this application, an electronic device is provided, wherein the electronic device includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor is capable of performing a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application or a state of charge determination method according to an exemplary embodiment of this application.

[0043] According to a seventh aspect of this application, a vehicle is provided, wherein the vehicle includes: a battery; and a control device configured as an electronic device according to exemplary embodiments of this application.

[0044] In various exemplary embodiments according to this application, the battery may in particular include a lithium iron phosphate battery. Attached Figure Description

[0045] The principles, features, and advantages of this application will be better understood below with reference to the accompanying drawings. The drawings include:

[0046] Figure 1The OCV-SOC curve of a lithium iron phosphate battery as an example is schematically shown;

[0047] Figure 2 A flowchart illustrating a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application is shown schematically.

[0048] Figure 3 The hysteresis coefficient determined in a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application is illustrated schematically.

[0049] Figure 4 The illustration schematically shows a logarithmic fit between the discharge current and the hysteresis coefficient in a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of the present application.

[0050] Figure 5 A flowchart illustrating a method for determining the state of charge of a battery according to an exemplary embodiment of this application is shown schematically.

[0051] Figure 6 A flowchart illustrating a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application is shown schematically.

[0052] Figure 7A and Figure 7B The hysteresis coefficient determined in a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application is illustrated schematically.

[0053] Figure 8A and Figure 8B An experiment used to verify the influencing factors of the hysteresis coefficient is illustrated schematically;

[0054] Figure 9 A flowchart illustrating a method for determining the state of charge of a battery according to an exemplary embodiment of this application is shown schematically; and

[0055] Figure 10 A vehicle according to an exemplary embodiment of this application is illustrated schematically. Detailed Implementation

[0056] To make the technical problems to be solved, the technical solutions, and the beneficial technical effects of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and several exemplary embodiments. It should be understood that the specific embodiments described herein are only for explaining this application and are not intended to limit the scope of protection of this application.

[0057] The following explanation uses a lithium iron phosphate battery as an example. However, it should be understood that hysteresis is widespread in various types of batteries. Therefore, this application is also applicable to other types of batteries, particularly lithium-ion batteries. The battery can, for example, be used as a power battery for vehicles. However, it should be understood that the concept of this application can also be applied to batteries for other applications. For example, the battery can also be used to power aircraft or ships.

[0058] Figure 1 The OCV-SOC curve of a lithium iron phosphate battery is schematically shown as an example. The OCV-SOC curve represents the relationship between the battery's open-circuit voltage (OCV) and its state of charge (SOC). Specifically, in Figure 1 The diagram shows the OCV-SOC charging curve L1, the OCV-SOC charging curve L2, and the average OCV-SOC curve L3.

[0059] The OCV-SOC charging curve L1 represents the relationship between OCV and SOC during battery charging. The OCV-SOC discharging curve L2 represents the relationship between OCV and SOC during battery discharging. It can be seen that due to the battery's hysteresis effect, the OCV-SOC curves are not consistent during charging and discharging. This results in the same SOC corresponding to different OCV values.

[0060] The average OCV-SOC curve L3 can be obtained by averaging the OCV-SOC charging curve L1 and the OCV-SOC discharging curve L2. Using the average OCV-SOC curve L3, the battery's SOC can be roughly determined based on the battery's OCV. However, the SOC determined in this way is often not accurate enough, which in turn makes it difficult to accurately calculate the battery's maximum capacity.

[0061] In addition, the SOC can be determined based on either the OCV-SOC charging curve L1 or the OCV-SOC charging curve L2, depending on the type of operation (charging or discharging) previously performed on the battery.

[0062] Specifically, the baseline OCV-SOC charging correspondence and baseline OCV-SOC discharging correspondence of the battery can be pre-calibrated through experiments.

[0063] The reference OCV-SOC charging correspondence can be calibrated, for example, through the following experiment. At a preset temperature and reference charging current, the battery is charged from 0% to 100% state of charge. The reference charging current can be, in particular, between 0.05C and 0.1C. For example, the reference charging current is 0.1C. During charging, whenever the battery's SOC increases by a preset SOC interval, the battery is allowed to rest for a period of time (e.g., 2-4 hours), and the battery's OCV is measured and recorded. The SOC interval can be, in particular, less than 10%, especially less than or equal to 5%, and optionally set to 1%. Based on the measured OCV and the corresponding SOC, the reference OCV-SOC charging correspondence can be determined.

[0064] The baseline OCV-SOC discharge correspondence can be calibrated, for example, through the following experiment. At a preset temperature and baseline discharge current, the battery is discharged from 100% state of charge to 0% state of charge. The baseline discharge current is particularly between 0.05C and 0.1C. For example, the baseline discharge current is 0.1C. During the discharge process, whenever the battery's SOC decreases by a preset SOC interval, the battery is allowed to rest for a period of time (e.g., 2-4 hours), and the battery's OCV is measured and recorded. The SOC interval is particularly less than 10%, especially less than or equal to 5%, and optionally set to 1%. Based on the measured OCV and the corresponding SOC, the baseline OCV-SOC discharge correspondence can be determined.

[0065] After charging, the State of Charge (SOC) of a battery can be determined using the reference OCV-SOC charging relationship. After discharging, the SOC can be determined using the reference OCV-SOC discharging relationship. The SOC determined in this way has relatively high accuracy, but still has a significant margin of error. In practice, batteries undergo complex and varied operating conditions. The theoretical OCV-SOC charging curves L1 and L2 do not match the actual conditions.

[0066] Therefore, this application proposes a concept to improve accuracy using a hysteresis coefficient. The hysteresis coefficient represents the degree of deviation of the battery's OCV-SOC correspondence from a reference OCV-SOC correspondence caused by the hysteresis effect. The impact of different operating conditions on the hysteresis coefficient can be predetermined through experiments. The reference OCV-SOC correspondence may include a reference OCV-SOC charging correspondence, a reference OCV-SOC discharging correspondence, and / or a reference average OCV-SOC correspondence.

[0067] Figure 2 A flowchart illustrating a method for calibrating the hysteresis coefficient of a battery according to an exemplary embodiment of this application is shown schematically.

[0068] like Figure 2As shown, the method for calibrating the hysteresis coefficient of a battery may include steps S110, S120 and S130.

[0069] In step S110, the battery is discharged from a first initial state of charge to a first target state of charge using n unequal discharge currents. After a predetermined resting time, the OCV of the battery corresponding to the first target state of charge is measured. n is greater than or equal to 2. The predetermined time may be greater than or equal to 6 hours, for example, 8 hours.

[0070] In step S120, the measured OCV is compared with the reference OCV determined according to the reference OCV-SOC correspondence to determine the hysteresis coefficient, which is used to represent the degree of deviation of the battery's OCV-SOC correspondence from the reference OCV-SOC correspondence caused by the hysteresis effect.

[0071] In step S130, the correspondence between the discharge current and the hysteresis coefficient is determined based on the n discharge currents and their corresponding hysteresis coefficients.

[0072] Therefore, the correspondence between discharge current and hysteresis coefficient can be obtained, which can be used to determine the hysteresis coefficient corresponding to the battery's discharge current during battery use. Using the hysteresis coefficient determined in this way, the battery's state of charge (SOC) can be determined more accurately based on the battery's open current velocity (OCV).

[0073] Through experiments, the inventors discovered that for the same discharge current, the hysteresis coefficient remains essentially constant, while different discharge currents have a significant impact on the hysteresis coefficient. Based on this discovery, the inventors proposed a method for calibrating the hysteresis coefficient of batteries, in order to quantitatively analyze the correspondence between discharge current and hysteresis coefficient.

[0074] According to an exemplary embodiment of this application, step S110 can be performed for each of m different first target states of charge, where m is greater than or equal to 2. Accordingly, in step S130, for each discharge current, the average hysteresis coefficient corresponding to the hysteresis coefficients of the m different first target states of charge is calculated, so as to determine the correspondence between the discharge current and the hysteresis coefficient based on each discharge current and the average hysteresis coefficient. This helps to determine the correspondence between the discharge current and the hysteresis coefficient more accurately.

[0075] Figure 3 The hysteresis coefficient determined in a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application is illustrated schematically.

[0076] In this embodiment, firstly, in step S110, the battery is discharged from a fully charged state to a first target state of charge at discharge currents (expressed as discharge rates) of 0.02C, 0.1C, 0.3C, 0.5C, and 1C respectively under a temperature of 25°C, and then left to stand for 8 hours. During this discharge process, the battery continuously discharges from a fully charged state to the first target state of charge. In other words, the battery does not pause discharge and / or stand still during this discharge process. Pausing discharge or standing still during the discharge process would affect the OCV measured in step S110.

[0077] To more accurately determine the correspondence between discharge current and hysteresis coefficient, step S110 is executed for each of the m different first target states of charge. For example, m is 5. Figure 3 It can be seen that the battery was discharged to five different first target states of charge: 10%, 12%, 15%, 18%, and 21%.

[0078] In practical applications, m and n can be set to larger values ​​to more comprehensively and accurately determine the correspondence between discharge current and hysteresis coefficient.

[0079] After the discharge process was completed, the battery was left to rest for 8 hours. Then, the OCV of the battery corresponding to the first target state of charge was measured.

[0080] In step S120, the measured OCV is compared with the reference OCV determined according to the reference OCV-SOC correspondence to determine the hysteresis coefficient. The hysteresis coefficient is used to represent the degree of deviation of the battery's OCV-SOC correspondence from the reference OCV-SOC correspondence caused by the hysteresis effect.

[0081] In particular, the hysteresis coefficient can be set to represent the degree of deviation of the battery's actual OCV-SOC correspondence from the reference average OCV-SOC correspondence. The reference average OCV-SOC correspondence represents the correspondence between SOC and the average value of OCV corresponding to the reference OCV-SOC charging correspondence and the reference OCV-SOC discharging correspondence, respectively. The sign of the hysteresis coefficient can be used to indicate the direction of deviation from the reference average OCV-SOC correspondence. The absolute value of the hysteresis coefficient can be used to represent the degree of deviation from the reference average OCV-SOC correspondence.

[0082] In an exemplary embodiment according to this application, a positive hysteresis coefficient (greater than 0) indicates a deviation from the reference average OCV-SOC correspondence towards the reference OCV-SOC charging correspondence; a negative hysteresis coefficient (less than 0) indicates a deviation from the reference average OCV-SOC correspondence towards the reference OCV-SOC discharging correspondence. The larger the absolute value of the hysteresis coefficient, the greater the degree of deviation from the reference average OCV-SOC correspondence.

[0083] The hysteresis coefficient for the reference OCV-SOC charging relationship is +1. The hysteresis coefficient for the reference OCV-SOC discharging relationship is -1.

[0084] By setting the hysteresis coefficient in this way, the impact of hysteresis on the battery can be better reflected in actual use.

[0085] Optionally, in step S120, the hysteresis coefficient is determined in the following manner:

[0086] λ=2*(OCV_M-(OCV_C+OCV_D) / 2) / (OCV_C-OCV_D)

[0087] Where λ represents the hysteresis coefficient, OCV_M represents the measured OCV, OCV_C represents the charging reference OCV corresponding to the first target state of charge based on the reference OCV-SOC charging correspondence, and OCV_D represents the discharging reference OCV corresponding to the first target state of charge based on the reference OCV-SOC discharging correspondence.

[0088] exist Figure 3 The diagram shows the m*n hysteresis coefficients thus determined. Here, the hysteresis coefficients determined using discharge processes with the same discharge current are connected together by dashed lines. Figure 3 The curves of the hysteresis coefficient are shown from top to bottom for discharge currents of 1C, 0.5C, 0.3C, 0.1C, and 0.02C, respectively.

[0089] It can be seen that the hysteresis coefficient remains essentially unchanged for the same discharge current. The first target state of charge has almost no effect on the hysteresis coefficient. Different discharge currents have a significant impact on the hysteresis coefficient. The smaller the discharge current, the larger the absolute value of the hysteresis coefficient.

[0090] In step S130, for each discharge current, the average hysteresis coefficient corresponding to the m different first target states of charge can be calculated, as shown in the table below.

[0091] Discharge current 0.02C 0.1C 0.3C 0.5C 1C Average hysteresis coefficient -1.25 -0.9 -0.65 -0.5 -0.25

[0092] The table also clearly shows that the smaller the discharge current, the larger the absolute value of the hysteresis coefficient.

[0093] Based on the discharge current and the average hysteresis coefficient, the correspondence between the discharge current and the hysteresis coefficient can be determined. In particular, the negative correlation between the absolute value of the discharge current and the hysteresis coefficient can be determined.

[0094] According to an exemplary embodiment of this application, in step S130, a logarithmic fit can be performed on the discharge current and the hysteresis coefficient to determine the following logarithmic relationship:

[0095] λ=a*ln(I_D)+b

[0096] Where λ represents the hysteresis coefficient, I_D represents the discharge current, and a and b are parameters determined by fitting.

[0097] Figure 4 The illustration schematically depicts logarithmic fitting of discharge current and hysteresis coefficient in a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application.

[0098] exist Figure 4 In the diagram, the horizontal axis represents the discharge current I_D, and the vertical axis represents the hysteresis coefficient λ. Figure 4 Five data points are illustrated as an example, each representing the discharge current and its corresponding average hysteresis coefficient. The logarithmic relationship between the discharge current and the hysteresis coefficient can be determined through logarithmic fitting, for example, expressed as λ = 0.2487ln(I_D) - 0.3064.

[0099] The relationship between discharge current and hysteresis coefficient can be stored, for example, as a functional expression, so that it can be used to determine the hysteresis coefficient corresponding to the battery's discharge current during battery use.

[0100] The relationship between discharge current and hysteresis coefficient can also be stored in the form of a lookup table.

[0101] Figure 5 A flowchart illustrating a method for determining the state of charge of a battery according to an exemplary embodiment of this application is shown schematically.

[0102] like Figure 5 As shown, the method for determining the state of charge of a battery may include steps S210, S220 and S230.

[0103] In step S210, the average discharge current of the battery during the discharge process is obtained.

[0104] In step S220, the hysteresis coefficient corresponding to the average discharge current is determined based on the correspondence between the discharge current and the hysteresis coefficient.

[0105] In step S230, based on the battery's OCV, the battery's SOC is determined according to the hysteresis coefficient and the correspondence between the reference OCV and SOC.

[0106] As mentioned above, the inventors discovered through experiments that the magnitude of the discharge current affects the hysteresis coefficient. By utilizing the correlation between discharge current and hysteresis coefficient, the hysteresis coefficient corresponding to the actual discharge current can be determined. Based on this, the state of charge (SOC) can be determined more accurately according to the discharge current velocity (OCV).

[0107] The battery can be used, for example, as a power battery for a vehicle. During vehicle operation, the battery discharges to provide energy to drive the vehicle. In this case, it can be utilized... Figure 5 The method shown is used to determine the state of charge (SOC) of a battery.

[0108] Optionally, in step S230, the actual OCV-SOC correspondence can be established using the hysteresis coefficient and the reference OCV-SOC correspondence. The SOC of the battery can be determined as the SOC corresponding to the actual OCV of the battery based on the actual OCV-SOC correspondence.

[0109] In one embodiment, a mapping table between open-circuit voltage, hysteresis coefficient, and state of charge (SOC) can be established. This mapping table can be established based on the correspondence between the hysteresis coefficient and a reference OCV-SOC. In step S230, the corresponding SOC can be determined based on the open-circuit voltage and hysteresis coefficient using this mapping table.

[0110] The relationship between discharge current and hysteresis coefficient can especially include the negative correlation between the absolute value of discharge current and hysteresis coefficient.

[0111] The relationship between discharge current and hysteresis coefficient can be determined using the hysteresis coefficient calibration method for batteries described above.

[0112] According to an exemplary embodiment of this application, the state of charge determination method may include utilizing the above-described combination of... Figures 2 to 4 The described method for hysteresis coefficient calibration of batteries determines the correspondence between discharge current and hysteresis coefficient.

[0113] For example, a hysteresis calibration method for the battery can be performed after the battery is installed in the vehicle. This determines the correspondence between the discharge current and the hysteresis coefficient that is compatible with the battery itself. The hysteresis calibration method can also be performed after a period of use to update the correspondence between the discharge current and the hysteresis coefficient.

[0114] Optionally, the relationship between discharge current and hysteresis coefficient can be pre-calibrated under laboratory conditions and then, for example, stored in the vehicle's battery management system (BMS).

[0115] Figure 6 A flowchart illustrating a method for calibrating the hysteresis coefficient of a battery according to an exemplary embodiment of this application is shown schematically.

[0116] like Figure 6 As shown, the method for calibrating the hysteresis coefficient of a battery may include steps S310, S320 and S330.

[0117] In step S310, after discharging the battery from the second initial state of charge to the second target state of charge with multiple unequal discharge currents, the battery is charged with a predetermined charging current until a predetermined state of charge increment is reached.

[0118] In step S320, the OCV of the battery under multiple different state-of-charge increments during the charging process in step S310 is measured, and the measured OCV is compared with the reference OCV determined according to the reference OCV-SOC correspondence to determine the hysteresis coefficient.

[0119] In step S330, based on the increment of state of charge and the corresponding hysteresis coefficient, the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval is determined, wherein the growth factor represents the increment or increase of the hysteresis coefficient.

[0120] Therefore, the correspondence between the hysteresis coefficient and its growth factor during the charging process after discharge can be obtained, which can be used to determine the battery's hysteresis coefficient during battery use. Using the hysteresis coefficient determined in this way, the battery's SOC can be determined more accurately based on its OCV.

[0121] The inventors discovered through experiments that during the charging process after discharge, the growth factor of the hysteresis coefficient is highly correlated with the hysteresis coefficient itself, while it is less correlated (or even uncorrelated) with other factors (such as the discharge current during discharge, the charging current during charging, or SOC).

[0122] Based on this discovery, the inventors proposed the following: Figure 6 The method shown is for calibrating the hysteresis coefficient of a battery in order to quantitatively analyze the correspondence between the hysteresis coefficient and its growth factor.

[0123] Figure 7A and Figure 7B The hysteresis coefficient determined in a hysteresis coefficient calibration method for a battery according to an exemplary embodiment of this application is illustrated schematically.

[0124] In this embodiment, firstly, in step S310, the battery is discharged to a 15% state of charge (SOC) using discharge currents of 0.1C, 0.5C, and 1C, respectively. Then, the battery is charged with a predetermined SOC increment using a charging current of 0.1C. The predetermined SOC increment is specifically at least 6%.

[0125] In step S320, the OCV of the battery under multiple different state-of-charge increments during the charging process in step S310 can be measured, and the measured OCV can be compared with the reference OCV determined according to the reference OCV-SOC correspondence to determine the hysteresis coefficient.

[0126] exist Figure 7A The diagram shows the reference OCV-SOC charging curve L1, reference OCV-SOC charging curve L2, and reference average OCV-SOC curve L3. Furthermore, broken lines L71, L72, and L73 illustrate the OCV of a battery that has undergone discharge at 1C, 0.5C, and 0.1C currents during subsequent charging processes. Figure 7A As shown, the OCV of the battery was measured at SOCs of 15%, 17%, 19%, and 21%.

[0127] Figure 7B The corresponding hysteresis coefficients are schematically shown, where the three broken lines from top to bottom represent the hysteresis coefficients of batteries that have undergone discharge currents of 1C, 0.5C, and 0.1C during the subsequent charging process.

[0128] The inventors discovered through experiments that when the increment of the state of charge is within the threshold of the increment of the state of charge, the hysteresis coefficient increases as the state of charge increases.

[0129] Furthermore, in step S330, based on the increment of the state of charge and the corresponding hysteresis coefficient, the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval can be determined, wherein the growth factor represents the increment or increase of the hysteresis coefficient.

[0130] from Figure 7B It can be seen that the smaller the hysteresis coefficient, the greater its increment within the next unit state of charge interval. Based on the correspondence between the hysteresis coefficient and its growth factor within the next unit state of charge interval, the hysteresis coefficient and its increment are negatively correlated.

[0131] In an exemplary embodiment, step S330 may determine the inverse relationship between the hysteresis coefficient and the hysteresis coefficient increment in the next unit state of charge interval.

[0132] Furthermore, when the increment of the state of charge exceeds the threshold of the increment of the state of charge, the hysteresis coefficient does not change with the state of charge.

[0133] Figure 7B It also shows the relationship between the initial hysteresis coefficient of the battery at the start of the charging process and its discharge current during the discharging process. This is in conjunction with the above. Figures 2 to 5 The description matches.

[0134] Figure 8A and Figure 8B An experiment used to verify the influencing factors of the hysteresis coefficient is illustrated schematically.

[0135] In this experiment, the battery was discharged to 15% SOC with the same discharge current, and then charged to 6% SOC with charging currents of 0.1C and 1C, respectively.

[0136] During charging, the battery's OCV can be measured at multiple different state-of-charge increments, and the measured OCV can be compared with the reference OCV determined according to the reference OCV-SOC correspondence to determine the hysteresis coefficient.

[0137] exist Figure 8A The diagram shows the reference OCV-SOC charging curve L1, reference OCV-SOC charging curve L2, and reference average OCV-SOC curve L3. Furthermore, broken lines L81 and L82 illustrate the OCV of the battery during charging at 0.1C and 1C charging currents, respectively. Figure 8A As shown, the OCV of the battery was measured at SOCs of 15%, 16%, 17%, 18%, 19%, 20%, and 21%.

[0138] Figure 8B The corresponding hysteresis coefficients are schematically shown, where the two broken lines from top to bottom represent the hysteresis coefficients of batteries charged with charging currents of 0.1C and 1C, respectively, during the charging process.

[0139] Through this experiment, the inventors discovered that during the charging process after discharge, the discharge current during the discharge process and the charging current during the charging process have little effect on the change in the hysteresis coefficient (so small that it can be ignored).

[0140] The table below exemplarily illustrates at least a portion of the lookup table for the hysteresis coefficient λ and the growth factor f. In this example, the growth factor f represents the increment of the hysteresis coefficient.

[0141] Lambda -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 f 0.6 0.56 0.52 0.48 0.44 0.4 0.36 0.32 0.28 0.24 0.2 0.16 0.12

[0142] The output of this lookup table is the growth factor, and the only input is the hysteresis coefficient; there are no other inputs. The hysteresis coefficient is negatively correlated with its increment. In other words, as the hysteresis coefficient increases, the corresponding increment of the hysteresis coefficient will decrease.

[0143] As an example, if the initial hysteresis coefficient is -0.8, then the corresponding growth factor can be determined to be 0.6 by looking up a table. Based on this, the hysteresis coefficient can be determined to be -0.2 after the next unit state of charge interval (e.g., 1%).

[0144] For the updated hysteresis coefficient of -0.2, the corresponding growth factor can be determined to be 0.36 by looking up a table. Based on this, the hysteresis coefficient can be determined to be 0.16 after the next unit state of charge interval. And so on.

[0145] Figure 9 A flowchart illustrating a method for determining the state of charge of a battery according to an exemplary embodiment of this application is shown schematically.

[0146] like Figure 9 As shown, the method for determining the state of charge may include steps S410 and S420.

[0147] In step S410, the initial hysteresis coefficient of the battery at the start of the charging process is obtained.

[0148] In step S420, the current hysteresis coefficient of the battery during the charging process is determined. The current hysteresis coefficient is the updated hysteresis coefficient obtained by increasing the previous hysteresis coefficient before the unit state of charge interval by a growth factor. The growth factor represents the increment or increase of the hysteresis coefficient. The growth factor is determined by using the previous hysteresis coefficient based on the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval.

[0149] As mentioned above, the inventors discovered through experiments that during the charging process after discharge, the growth factor of the hysteresis coefficient is highly correlated with the hysteresis coefficient itself, but less correlated with other factors (e.g., the discharge current during discharge, the charging current during charging, or the State of Charge (SOC)). By utilizing the correspondence between the hysteresis coefficient and its growth factor within the next unit state of charge interval, the growth factor can be determined, and thus the current hysteresis coefficient can be determined. Based on the hysteresis coefficient determined in this way, the State of Charge (SOC) can be determined more accurately according to the OCV (Optical Characteristic Value).

[0150] For example, when the battery is used as a power battery in a vehicle, this state of charge (SOC) determination method is particularly suitable for determining the battery's SOC during the regeneration phase. During regeneration, the battery is typically in a post-discharge charging process and usually only undergoes a small-scale recharge. During this small-scale recharge, the SOC increment typically does not exceed a SOC increment threshold.

[0151] According to an exemplary embodiment of this application, the growth factor is determined solely based on the previous hysteresis coefficient. The growth factor of the current hysteresis coefficient is only related to the previous hysteresis coefficient and is independent of factors such as the charging current during charging, the discharging current during discharging, and / or the state of charge (SOC).

[0152] In practice, the hysteresis coefficient can be determined relatively accurately and explicitly, serving as the basis for determining the growth factor. In contrast, factors such as charging current, discharging current, or State of Charge (SOC) are often difficult to determine accurately and explicitly. For example, charging current or discharging current may fluctuate. Expressing it as an average value can easily introduce errors. SOC itself is estimated from other parameters, which can also introduce errors. Therefore, determining the growth factor based solely on the preceding hysteresis coefficient helps avoid introducing errors.

[0153] Referring to the above text Figures 2 to 5 The concept described suggests that the initial hysteresis coefficient can be determined based on the average discharge current of the battery during the discharge process.

[0154] Optionally, the method for determining the state of charge further includes steps S430 and S440.

[0155] In step S430, it is determined whether the increase in the state of charge (SOC) of the battery during charging exceeds a SOC increment threshold. If the SOC increment is within the threshold, step S420 is executed; if the SOC increment exceeds the threshold, step S440 is executed. The SOC increment threshold can optionally be set to 6%.

[0156] In step S440, the hysteresis coefficient can be set to a predetermined value, or the hysteresis coefficient can remain unchanged.

[0157] This application also relates to an electronic device, wherein the electronic device includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor is capable of executing a hysteresis coefficient calibration method and / or a state of charge determination method according to exemplary embodiments of this application.

[0158] As an example, electronic devices can be implemented as part of the BMS of an electric vehicle.

[0159] Alternatively, the electronic device may be implemented as a dedicated device specifically for calibrating the hysteresis coefficient.

[0160] Figure 10 A vehicle 1 according to an exemplary embodiment of this application is schematically shown. The vehicle 1 includes a battery 11, which serves as a power battery for providing driving force to propel the vehicle 1. The vehicle 1 also includes a control device 12.

[0161] The control device 12 may include a memory and a processor, wherein the memory stores a computer program that, when executed by the processor, enables the processor to perform a state-of-charge determination method and / or a hysteresis coefficient calibration method for a battery according to exemplary embodiments of this application. The computer program instructions may be stored in a computer-readable storage medium. The computer-readable storage medium may include, for example, high-speed random access memory, and may also include non-volatile memory or volatile solid-state storage devices. The processor may be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, off-the-shelf programmable gate arrays, or other programmable logic devices.

[0162] The control device 12 can be implemented as part of the BMS. For example, the control device 12 can be implemented as the main control unit (MCU) of the battery management system or integrated into the main control unit.

[0163] Although specific embodiments of this application are described in detail herein, they are given for illustrative purposes only and should not be construed as limiting the scope of this application. Various substitutions, modifications, and alterations can be conceived without departing from the spirit and scope of this application.

Claims

1. A method for calibrating the hysteresis coefficient of a battery, wherein, The hysteresis coefficient calibration method includes the following steps: S110, the battery is discharged from the first initial state of charge to the first target state of charge with multiple unequal discharge currents respectively, and after being left to stand for a predetermined time, the open circuit voltage of the battery corresponding to the first target state of charge is measured. S120, compare the measured open-circuit voltage with the reference open-circuit voltage determined according to the reference OCV-SOC correspondence to determine the hysteresis coefficient, which represents the degree of deviation of the battery's OCV-SOC correspondence from the reference OCV-SOC correspondence caused by the hysteresis effect. as well as S130, Based on the plurality of discharge currents and their corresponding hysteresis coefficients, determine the correspondence between the discharge current and the hysteresis coefficient.

2. The hysteresis coefficient calibration method according to claim 1, wherein, The hysteresis coefficient is set to represent the degree of deviation of the actual OCV-SOC correspondence of the battery from the reference average OCV-SOC correspondence. The reference average OCV-SOC correspondence represents the correspondence between the state of charge and the average value of the open-circuit voltage corresponding to the reference OCV-SOC charging correspondence and the reference OCV-SOC discharging correspondence, respectively. The sign of the hysteresis coefficient is used to indicate the direction of deviation from the reference average OCV-SOC correspondence, and the absolute value of the hysteresis coefficient is used to indicate the degree of deviation from the reference average OCV-SOC correspondence. The larger the absolute value of the hysteresis coefficient, the greater the degree of deviation from the reference average OCV-SOC correspondence.

3. The hysteresis coefficient calibration method according to claim 2, wherein, In step S130, the negative correlation between the discharge current and the absolute value of the hysteresis coefficient is determined; and / or In step S130, a logarithmic fit is performed on the discharge current and the hysteresis coefficient to determine the following logarithmic relationship: λ=a*ln(I_D)+b Where λ represents the hysteresis coefficient, I_D represents the discharge current, and a and b are parameters determined by fitting.

4. The hysteresis coefficient calibration method according to any one of claims 1-3, wherein, In step S120, the hysteresis coefficient is determined in the following manner: λ=2*(OCV_M-(OCV_C+OCV_D) / 2) / (OCV_C-OCV_D) Where λ represents the hysteresis coefficient, OCV_M represents the measured open-circuit voltage, OCV_C represents the charging reference open-circuit voltage corresponding to the first target state of charge based on the reference OCV-SOC charging correspondence, and OCV_D represents the discharging reference open-circuit voltage corresponding to the first target state of charge based on the reference OCV-SOC discharging correspondence.

5. The hysteresis coefficient calibration method according to any one of claims 1-4, wherein, For each of the multiple different first target states of charge, step S110 is executed respectively; In step S130, for each discharge current, the average hysteresis coefficient corresponding to the plurality of different first target states of charge is calculated, so as to determine the correspondence between the discharge current and the hysteresis coefficient based on each discharge current and the average hysteresis coefficient.

6. The hysteresis coefficient calibration method according to any one of claims 1-5, wherein, In step S110, the battery is discharged from a fully charged state to a first target state of charge at discharge currents of 0.02C, 0.1C, 0.3C, 0.5C, and 1C respectively under a temperature of 25°C, and then left to stand for 8 hours; and / or The battery is a lithium iron phosphate battery.

7. A method for determining the state of charge of a battery, wherein, The method for determining the state of charge includes the following steps: S210, obtain the actual open-circuit voltage of the battery and the average discharge current of the battery during the discharge process; S220, Based on the correspondence between discharge current and hysteresis coefficient, determine the hysteresis coefficient corresponding to the average discharge current, wherein the hysteresis coefficient represents the degree of deviation of the battery's OCV-SOC correspondence caused by the hysteresis effect from the reference OCV-SOC correspondence. as well as S230 determines the state of charge of the battery based on the actual open-circuit voltage of the battery and the correspondence between the hysteresis coefficient and the reference OCV-SOC.

8. The method for determining the state of charge according to claim 7, wherein, The hysteresis coefficient is set to represent the degree of deviation of the actual OCV-SOC correspondence of the battery from the reference average OCV-SOC correspondence. The reference average OCV-SOC correspondence represents the correspondence between the state of charge and the average value of the open-circuit voltage corresponding to the reference OCV-SOC charging correspondence and the reference OCV-SOC discharging correspondence, respectively. The sign of the hysteresis coefficient is used to indicate the direction of deviation from the reference average OCV-SOC correspondence, and the absolute value of the hysteresis coefficient is used to indicate the degree of deviation from the reference average OCV-SOC correspondence. The larger the absolute value of the hysteresis coefficient, the greater the degree of deviation from the reference average OCV-SOC correspondence.

9. The method for determining the state of charge according to claim 8, wherein, The relationship between discharge current and hysteresis coefficient includes the negative correlation between the absolute values ​​of discharge current and hysteresis coefficient.

10. The method for determining the state of charge according to any one of claims 7-9, wherein, The relationship between discharge current and hysteresis coefficient is determined by the hysteresis coefficient calibration method for batteries according to any one of claims 1-6; and / or The method for determining the state of charge includes using the hysteresis coefficient calibration method for batteries according to any one of claims 1-6 to determine the correspondence between the discharge current and the hysteresis coefficient; and / or The battery is a lithium iron phosphate battery.

11. A method for calibrating the hysteresis coefficient of a battery, wherein, The hysteresis coefficient calibration method includes the following steps: S310, after discharging the battery from the second initial state of charge to the second target state of charge with multiple unequal discharge currents respectively, the battery is charged with a predetermined charging current until a predetermined state of charge increment is reached. S320, Measure the open-circuit voltage of the battery under multiple different state-of-charge increments during the charging process in step S310, and compare the measured open-circuit voltage with the reference open-circuit voltage determined according to the reference OCV-SOC correspondence to determine the hysteresis coefficient, which is used to represent the degree of deviation of the battery's OCV-SOC correspondence from the reference OCV-SOC correspondence caused by the hysteresis effect. as well as S330, based on the increment of state of charge and the corresponding hysteresis coefficient, determine the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval, wherein the growth factor represents the increment or increase of the hysteresis coefficient.

12. The hysteresis coefficient calibration method according to claim 11, wherein, The hysteresis coefficient is set to represent the degree of deviation of the actual OCV-SOC correspondence of the battery from the reference average OCV-SOC correspondence. The reference average OCV-SOC correspondence represents the correspondence between the state of charge and the average value of the open-circuit voltage corresponding to the reference OCV-SOC charging correspondence and the reference OCV-SOC discharging correspondence, respectively. The sign of the hysteresis coefficient is used to indicate the direction of deviation from the reference average OCV-SOC correspondence, and the absolute value of the hysteresis coefficient is used to indicate the degree of deviation from the reference average OCV-SOC correspondence. The larger the absolute value of the hysteresis coefficient, the greater the degree of deviation from the reference average OCV-SOC correspondence.

13. The hysteresis coefficient calibration method according to claim 11 or 12, wherein, The predetermined state-of-charge increment is at least 6%; and / or In step S310, after discharging the battery to 15% state of charge with discharge currents of 0.1C, 0.5C, and 1C respectively, the battery is charged with a charging current of 0.1C until the state of charge increment reaches 6% or more; and / or The battery is a lithium iron phosphate battery.

14. A method for determining the state of charge of a battery, wherein, The battery undergoes a charging process after a discharging process, and the method for determining the state of charge includes the following steps: S410, obtain the initial hysteresis coefficient of the battery at the start of the charging process; as well as S420, during the charging process, the current hysteresis coefficient of the battery is the updated hysteresis coefficient obtained by increasing the previous hysteresis coefficient before the unit state of charge interval by a growth factor. The growth factor represents the increment or increase of the hysteresis coefficient. The growth factor is determined by using the previous hysteresis coefficient based on the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval.

15. The method for determining the state of charge according to claim 14, wherein, The hysteresis coefficient is set to represent the degree of deviation of the actual OCV-SOC correspondence of the battery from the reference average OCV-SOC correspondence. The reference average OCV-SOC correspondence represents the correspondence between the state of charge and the average value of the open-circuit voltage corresponding to the reference OCV-SOC charging correspondence and the reference OCV-SOC discharging correspondence, respectively. The sign of the hysteresis coefficient is used to indicate the direction of deviation from the reference average OCV-SOC correspondence, and the absolute value of the hysteresis coefficient is used to indicate the degree of deviation from the reference average OCV-SOC correspondence. The larger the absolute value of the hysteresis coefficient, the greater the degree of deviation from the reference average OCV-SOC correspondence.

16. The method for determining the state of charge according to claim 14 or 15, wherein, The growth factor is determined solely based on the previous lag coefficient; and / or The initial hysteresis coefficient is determined based on the average discharge current of the battery during the discharge process.

17. The method for determining the state of charge according to any one of claims 14-16, wherein, The correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval is determined by the hysteresis coefficient calibration method for batteries according to claim 11 or 12; and / or The method for determining the state of charge includes using the hysteresis coefficient calibration method for batteries according to claim 11 or 12 to determine the correspondence between the hysteresis coefficient and the growth factor of the hysteresis coefficient in the next unit state of charge interval. and / or The battery is a lithium iron phosphate battery.

18. The method for determining the state of charge according to any one of claims 14-17, wherein, The method for determining the state of charge further includes the following steps: S430, determine whether the increase in the state of charge (SOC) of the battery during charging exceeds a SOC increment threshold. If the SOC increment is within the SOC increment threshold, proceed to step S420; if the SOC increment exceeds the SOC increment threshold, proceed to step S440. The SOC increment threshold can optionally be set to 6%. S440, the hysteresis coefficient is set to a predetermined value, or the hysteresis coefficient remains unchanged.

19. A computer program product comprising computer program instructions, wherein, When the computer program instructions are executed by one or more processors, the one or more processors are able to perform the hysteresis coefficient calibration method for a battery according to any one of claims 1-6, 11-13 or the state of charge determination method according to any one of claims 7-10, 14-18.

20. An electronic device, wherein, The electronic device includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor is capable of performing the hysteresis coefficient calibration method for a battery according to any one of claims 1-6, 11-13 or the state of charge determination method according to any one of claims 7-10, 14-18.

21. A vehicle, wherein, The vehicles include: Batteries; and A control device configured as the electronic device according to claim 20.

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