A method, system and vehicle for correcting state of charge value

Abstract

The present invention provides a method, system and vehicle for correcting state of charge value, wherein the method comprises: determining the estimated state of charge value of the battery according to the initial state of charge value of the battery and the charge and discharge current of the battery; obtaining the current open circuit voltage value of the battery; determining the corrected state of charge value corresponding to the current open circuit voltage value according to the state of charge and open circuit voltage relationship curve of the battery; determining the correlation strength value between the current open circuit voltage value and the state of charge value of the battery according to the state of charge and open circuit voltage relationship curve and the corrected state of charge value; and correcting the estimated state of charge value according to the corrected state of charge value when the correlation strength value is greater than the correlation strength threshold. The present invention can reduce or even avoid the correction deviation of the state of charge value caused by the sampling error of the open circuit voltage, avoid the problem of erroneous correction caused by the sampling error, and thus improve the accuracy of SOC correction.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a method, system and vehicle for correcting a state of charge value of a lithium battery. Background Art

[0002] At present, in the lithium-powered battery management system for electric vehicles, the estimation of the battery state of charge is the core content of the battery management system. If the SOC estimation value is too low, the vehicle will not be able to use the maximum power performance; if the SOC estimation value is too high, it will lead to overuse of the battery and reduce the battery life.

[0003] The accuracy of battery SOC estimation depends on the SOC correction algorithm. The existing method uses the state of charge-open circuit voltage (SOC-OCV) curve to correct the estimated SOC value. Specifically, the SOC value obtained by looking up the single cell open circuit voltage table is used to correct the SOC estimated value. However, due to the sampling error of the single cell voltage, the SOC value obtained by the SOC-OCV curve will have a certain error, resulting in poor SOC correction effect, which in turn affects the accuracy of SOC estimation. Summary of the invention

[0004] In view of this, the present invention aims to propose a method, system and vehicle for correcting the state of charge value, so as to solve the problem that the existing method of correcting the estimated SOC value using the SOC-OCV curve is prone to correction deviation due to the sampling error of the single cell voltage.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A method for correcting a state of charge value, wherein the method comprises:

[0007] Determining an estimated state of charge value of the battery according to an initial state of charge value of the battery and a charge and discharge current of the battery;

[0008] Obtaining a current open circuit voltage value of the battery;

[0009] Determining a corrected state of charge value corresponding to the current open circuit voltage value according to a state of charge and open circuit voltage relationship curve of the battery;

[0010] Determining a correlation strength value between the current open circuit voltage value and the state of charge value of the battery according to the state of charge and open circuit voltage relationship curve and the corrected state of charge value;

[0011] In a case where the correlation strength value is greater than a correlation strength threshold, the estimated state of charge value is corrected according to the corrected state of charge value.

[0012] Further, in the state of charge value correction method, determining the correlation strength value between the current open circuit voltage value and the state of charge value of the battery according to the state of charge and open circuit voltage relationship curve of the battery and the corrected state of charge value includes:

[0013] Performing differentiation processing on the relationship curve between the state of charge and the open circuit voltage of the battery to obtain a correlation strength curve between the state of charge and the open circuit voltage of the battery;

[0014] The correlation strength value is determined according to the correlation strength curve and the corrected state of charge value.

[0015] Furthermore, in the state of charge value correction method, when the correlation strength value is greater than a correlation strength threshold, the estimated state of charge value is corrected according to the corrected state of charge value, specifically including:

[0016] In a case where the correlation strength value is greater than a correlation strength threshold, the estimated state of charge value is replaced with the corrected state of charge value.

[0017] Furthermore, in the state of charge value correction method, the correlation strength threshold is greater than or equal to the sampling error of the open circuit voltage value.

[0018] Furthermore, in the method for correcting the state of charge value, the method further includes:

[0019] In a case where the correlation strength value is less than or equal to the correlation strength threshold, determining the estimated state of charge value is a corrected state of charge value.

[0020] Furthermore, in the state of charge value correction method, determining the estimated state of charge value of the battery according to the initial state of charge value of the battery and the charge and discharge current of the battery includes:

[0021] Integrate the time according to the charge and discharge current of the battery to determine the charge change;

[0022] The estimated state of charge value is determined according to the charge change and the initial state of charge value.

[0023] Furthermore, in the method for correcting the state of charge value, obtaining the current open circuit voltage value of the battery includes:

[0024] When the static time of the battery is greater than or equal to a preset time threshold, obtaining a voltage value of each single cell of the battery;

[0025] The current open circuit voltage value is determined according to each of the static cell voltage values.

[0026] Another object of the embodiment of the present application is to provide a state of charge value correction system, wherein the system includes:

[0027] A first determination module, configured to determine an estimated state of charge value of the battery according to a preset state of charge value estimation method;

[0028] An acquisition module, used for acquiring a current open circuit voltage value of the battery;

[0029] A second determination module, configured to determine a corrected state of charge value corresponding to the current open circuit voltage value according to a state of charge and open circuit voltage relationship curve of the battery;

[0030] a third determination module, configured to determine a correlation strength value between the current open circuit voltage value and the state of charge value of the battery according to the state of charge and open circuit voltage relationship curve and the corrected state of charge value;

[0031] The first correction module is used to correct the estimated state of charge value according to the corrected state of charge value when the correlation strength value is greater than a correlation strength threshold.

[0032] Furthermore, in the state of charge value correction system, the third determination module includes:

[0033] A differential unit, used for performing differential processing on the relationship curve between the state of charge and the open circuit voltage of the battery to obtain a correlation strength curve between the state of charge and the open circuit voltage of the battery;

[0034] A determination unit is used to determine the correlation strength value according to the correlation strength curve and the corrected state of charge value.

[0035] Furthermore, in the state of charge value correction system, the correction module is specifically used to replace the estimated state of charge value with the corrected state of charge value when the correlation strength value is greater than a correlation strength threshold.

[0036] Furthermore, in the state of charge value correction system, the system further includes:

[0037] The second correction module is used to determine that the estimated state of charge value is a corrected state of charge value when the correlation strength value is less than or equal to the correlation strength threshold.

[0038] Another object of the present invention is to provide a vehicle, the vehicle comprising a battery, wherein the vehicle further comprises the state of charge value correction system as described above.

[0039] Compared with the prior art, the method, system and vehicle for correcting the state of charge value of the present invention have the following advantages:

[0040] First, the estimated state of charge value of the battery is determined through the initial state of charge value of the battery and the charge and discharge current of the battery, and the current open circuit voltage value of the battery is obtained; then, based on the relationship curve between the state of charge and the open circuit voltage of the battery, the corrected state of charge value corresponding to the above-mentioned current open circuit voltage value is determined; then, based on the above-mentioned state of charge and the open circuit voltage relationship curve and the above-mentioned corrected state of charge value, the correlation strength value between the above-mentioned current open circuit voltage value and the state of charge value of the above-mentioned battery is determined; when the above-mentioned correlation strength value is greater than the correlation strength threshold, the above-mentioned estimated state of charge value is corrected according to the above-mentioned corrected state of charge value. Among them, when the correlation strength value between the current open circuit voltage value of the battery and the state of charge value of the battery is greater than the correlation strength threshold, it means that the current open circuit voltage value is greatly affected by the state of charge value of the battery. At this time, the estimated state of charge value of the battery is corrected by querying the state of charge and open circuit voltage relationship curve through the current open circuit voltage value, and the corrected state of charge value is obtained. This can reduce or even avoid the state of charge value correction deviation caused by the sampling error of the open circuit voltage, avoid the problem of erroneous correction caused by sampling error, and thus improve the accuracy of SOC correction. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0042] Figure 1 A schematic diagram of a flow chart of a method for correcting a state of charge value proposed in an embodiment of the present application;

[0043] Figure 2 This is a schematic diagram of the SOC-OCV curve of the lithium iron phosphate battery in the embodiment of the present application;

[0044] Figure 3 for Figure 2 The curve diagram of SOC-OCV obtained after differential processing;

[0045] Figure 4 This is a schematic diagram of the SOC-OCV curve of the ternary lithium iron phosphate battery in the embodiment of the present application;

[0046] Figure 5 for Figure 4 The curve diagram obtained after the SOC-OCV curve is differentiated;

[0047] Figure 6 This is a schematic diagram of the structure of the state of charge value correction system proposed in an embodiment of the present application. DETAILED DESCRIPTION

[0048] Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present application and to enable the scope of the present application to be fully conveyed to those skilled in the art.

[0049] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0050] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0051] See also Figure 1 , shows a flow chart of a method for correcting a state of charge value provided in an embodiment of the present application. The method for correcting a state of charge value provided in an embodiment of the present application includes steps S100 to S500.

[0052] The embodiment of the present application can be specifically applied to a battery management system of a vehicle for correcting the SOC value of a battery, wherein the battery can be a power battery of the vehicle, specifically a lithium battery or other storage battery, wherein the lithium battery can be a lithium iron phosphate battery or a ternary lithium battery.

[0053] Step S100: determining an estimated state of charge of the battery according to the initial state of charge of the battery and the charge and discharge current of the battery.

[0054] In the above step S100, the above initial state of charge value refers to the state of charge value of the battery before the last operation started, specifically the state of charge value obtained after the last correction; the method of using a preset state of charge value estimation algorithm to estimate the state of charge value of the battery in real time, specifically, using the ampere-hour integration method, according to the initial state of charge value of the battery and the charge and discharge current generated by the battery during the charge and discharge process, to estimate the real-time state of charge value of the battery, so as to obtain the above estimated state of charge value.

[0055] However, due to sampling accuracy limitations, the ampere-hour integration method may produce large cumulative errors after long-term operation, so it is necessary to use subsequent methods to correct the estimated state of charge value.

[0056] Step S200: Obtain the current open circuit voltage value of the battery.

[0057] In the above step S200, the open circuit voltage value (OCV) refers to the static open circuit voltage of the battery cell, which is specifically determined by collecting the static single cell voltage of the battery through the battery management system (BMS); wherein, since the battery cell will produce polarization after charging or discharging, the external characteristic voltage of the battery cell is inconsistent with the open circuit static voltage of the battery cell. Therefore, when measuring the open circuit voltage value of the battery, the battery cell needs to be left to stand to eliminate polarization. The battery voltage measured after standing is the OCV.

[0058] Among them, the above-mentioned current open circuit voltage value is the static open circuit voltage of the battery cell when the estimated SOC of the battery is corrected, that is, when the battery is left stationary for more than a preset time, until the polarization of the battery cell is eliminated, and the battery is started again, the state of charge value correction method provided in the embodiment of the present application is executed to correct the estimated battery state of charge value.

[0059] S300: Determine a corrected state of charge value corresponding to the current open circuit voltage value according to a curve of relationship between the state of charge and the open circuit voltage of the battery.

[0060] In the above step S300, the above state of charge and open circuit voltage relationship curve, that is, the SOC-OCV curve is a characteristic curve of the battery. Because the curve expresses the corresponding relationship between the open circuit voltage of the battery and the state of charge value of the battery, the state of charge value corresponding to the above actual open circuit voltage, that is, the above corrected state of charge value, can be queried based on the SOC-OCV curve.

[0061] S400, determining a correlation strength value between the current open circuit voltage value and the state of charge value of the battery according to the state of charge and open circuit voltage relationship curve and the corrected state of charge value.

[0062] In the above step S400, the above correlation strength value is the degree to which the open circuit voltage of the battery is affected by the state of charge value of the battery, that is, it reflects the degree to which the open circuit voltage of the battery is affected by the state of charge value; if the correlation strength value is larger, it means that the open circuit voltage value is affected by the change of the state of charge value. Changes; and if the correlation strength value is smaller, it means that the open circuit voltage value is affected by the change of the state of charge value. Changes are smaller.

[0063] In the above step S400, because the SOC-OCV curve expresses the corresponding relationship between the open circuit voltage of the battery and the state of charge value of the battery, it is possible to determine the change in the corresponding open circuit voltage caused by the change in the state of charge value when the battery is in different open circuit voltage states, that is, to determine the size of the corresponding correlation strength value.

[0064] S500: When the correlation strength value is greater than a correlation strength threshold, correct the estimated state of charge value according to the corrected state of charge value.

[0065] In the above step S500, the above correlation strength threshold is a correlation strength value for determining whether the open circuit voltage is greatly changed by the change of the state of charge value, that is, a relative strength value for determining whether the open circuit voltage is mainly affected by the change of the state of charge value; when the correlation strength value corresponding to the actual open circuit voltage is greater than the above correlation strength threshold, it means that the open circuit voltage is greatly changed by the change of the state of charge value, that is, the open circuit voltage is mainly affected by the change of the state of charge value, rather than being mainly affected by the sampling error of the open circuit voltage. At this time, the estimated state of charge value is corrected according to the above corrected state of charge value, which can at least ensure that the corrected state of charge value is closer to the actual state of charge value of the battery than the estimated state of charge value, that is, it can make up for the correction deviation caused by the sampling error of the open circuit voltage, avoid the problem of erroneous correction due to the sampling error, and thus improve the accuracy of SOC correction.

[0066] Compared with the prior art, the charge state value correction method of the present invention has the following advantages:

[0067] When the correlation strength value between the current open circuit voltage value of the battery and the state of charge value of the battery is greater than the correlation strength threshold, it means that the current open circuit voltage value is greatly affected by the state of charge value of the battery. At this time, the estimated state of charge value of the battery is corrected by querying the state of charge and open circuit voltage relationship curve through the current open circuit voltage value. This can reduce or even avoid the state of charge value correction deviation caused by the sampling error of the open circuit voltage, avoid the problem of erroneous correction caused by sampling error, thereby improving the accuracy of SOC correction, thereby solving the problem in the prior art that the method of using the SOC-OCV curve to correct the estimated SOC value is prone to correction deviation due to the sampling error of the single cell voltage.

[0068] Optionally, in one implementation, in the state of charge value correction method provided in the embodiment of the present application, the above step S100 specifically includes steps S101 to S102:

[0069] S101. Integrate time according to the charge and discharge current of the battery to determine the charge and discharge amount.

[0070] In the above step S101, the ampere-hour integration method is used to integrate the charge and discharge current of the battery with respect to time during the operation of the battery to obtain the charge amount generated during the charge and discharge process, that is, the charge change amount.

[0071] S102: Determine the estimated state of charge value according to the charge change and the initial state of charge value.

[0072] In the above step S102, the estimated state of charge of the battery can be estimated in real time based on the charge change amount combined with the initial state of charge of the battery.

[0073] In practical applications, other existing state of charge value algorithms may also be used to calculate the above estimated state of charge value.

[0074] Optionally, in one implementation, in the state of charge value correction method provided in the embodiment of the present application, the above step S200 specifically includes steps S201 to S202:

[0075] S201. When the static time of the battery is greater than or equal to a preset time threshold, obtain a static single cell voltage value of the battery.

[0076] In the above step S201, the above-mentioned resting time is the time length during which the battery stops charging and discharging. Because the battery cell will produce polarization after charging or discharging, the external characteristic voltage of the battery cell is inconsistent with the open circuit resting voltage of the battery cell, so the battery cell needs to be left at rest for a certain period of time to eliminate polarization; the above-mentioned preset time length threshold is used to determine the time length for eliminating polarization.

[0077] In the above step S201, when the static time of the battery reaches the preset time threshold, the polarization of the battery is eliminated, and the battery management system can be used to obtain the voltage value of each cell in the battery to obtain the above static cell voltage value.

[0078] S202: Determine the current open circuit voltage value according to each of the static cell voltage values.

[0079] In the above step S202, each static cell voltage value reflects the voltage condition of each battery cell constituting the battery, and thus the above current open circuit voltage value can be calculated using the above static cell voltage values.

[0080] Optionally, in one implementation, in the state of charge value correction method provided in the embodiment of the present application, the above step S400 specifically includes steps S401 to S402:

[0081] S401, performing differentiation processing on the relationship curve between the state of charge and the open circuit voltage of the battery to obtain a correlation strength curve between the state of charge and the open circuit voltage of the battery.

[0082] In the above step S401, since the state of charge and open circuit voltage relationship curve expresses the relationship between the open circuit voltage and the state of charge value, the above curve is differentiated to obtain the intensity of the change of the open circuit voltage with the state of charge value, that is, the intensity of the correlation between the open circuit voltage value and the state of charge value can be reflected;

[0083] Specifically, the state of charge and open circuit voltage relationship curve is differentiated with respect to the state of charge value, and the obtained curve is a curve that can reflect the intensity of the change of the open circuit voltage with the change of the state of charge value, that is, the above-mentioned correlation intensity curve.

[0084] In the above step S401, the change of SOC is differentiated by the single cell voltage in the battery, and the correlation strength d S =d V / d SOC , where d V When SOC changes d SOC The absolute value of the single cell voltage change when

[0085] In the present application embodiment, d S It is expressed as the absolute value of the slope at each state of charge value in the SOC-OCV curve.

[0086] S402: Determine the correlation strength value according to the correlation strength curve and the corrected state of charge value.

[0087] In the above step S402, because the above correlation strength curve reflects the curve of the intensity of the change of the open circuit voltage with the change of the state of charge value, the corrected state of charge value corresponding to the above actual open circuit voltage is substituted into the above correlation strength curve to determine the correlation strength value between the actual open circuit voltage and the actual state of charge value of the battery, and then determine whether it is necessary to use the corrected state of charge value to correct the estimated state of charge value.

[0088] In this embodiment, the SOC-OCV curve is differentiated to calculate the rate of change of the open circuit voltage corresponding to the corrected state of charge value, and the rate of change is used as the correlation strength value between the corresponding open circuit voltage and the state of charge value, so as to simply and quickly determine whether the currently monitored open circuit voltage can be used to correct the estimated state of charge value.

[0089] Optionally, in one implementation, in the state of charge value correction method provided in the embodiment of the present application, the above step S500 specifically includes step S501.

[0090] Step S501: When the correlation strength value is greater than a correlation strength threshold, the estimated state of charge value is replaced by the corrected state of charge value.

[0091] In the above step S501, when the above correlation strength value is greater than the correlation strength threshold, it means that the open circuit voltage of the battery in the current state is mainly affected by the change of the state of charge value. At this time, the open circuit voltage has a strong linear relationship with the actual state of charge value of the battery. The corrected state of charge value corresponding to the open circuit voltage is closer to the actual state of charge value of the battery than the estimated state of charge value. Therefore, the corrected state of charge value corresponding to the open circuit voltage can be used to replace the above estimated state of charge value, thereby completing the correction of the estimated state of charge value.

[0092] Optionally, in a specific embodiment, the above-mentioned correlation strength threshold is greater than or equal to the sampling error of the above-mentioned open circuit voltage value, which can ensure that when the estimated state of charge value is corrected using the corrected state of charge value corresponding to the actual open circuit voltage, the correction difference of the estimated state of charge value is greater than or equal to the error caused by the sampling error, and at least it can ensure that the corrected state of charge value is closer to the true state of charge value of the battery than the estimated state of charge value, that is, it can compensate for the correction deviation caused by the sampling error of the open circuit voltage, avoid the problem of erroneous correction due to the sampling error, and thus improve the accuracy of SOC correction.

[0093] Optionally, in one implementation, the method for correcting the state of charge value provided in the embodiment of the present application further includes step S502.

[0094] Step S502: When the correlation strength value is less than or equal to the correlation strength threshold, determine that the estimated state of charge value is a corrected state of charge value.

[0095] In the above step S502, when the above correlation strength value is less than or equal to the correlation strength threshold, it means that the open circuit voltage of the battery in the current state is not greatly affected by the change of the state of charge value. At this time, the linear relationship between the open circuit voltage and the actual state of charge value of the battery is weak. The corrected state of charge value corresponding to the open circuit voltage cannot well reflect the true state of charge value of the battery, which is not conducive to correcting the estimated state of charge value with the corrected state of charge value corresponding to the open circuit voltage, and the above estimated state of charge value is directly determined as the corrected state of charge value.

[0096] In practical applications, taking lithium iron phosphate battery as an example, its SOC-OCV curve is as follows: Figure 2 As shown in the figure, it can be seen that the above curve does not have good discrimination in most positions of the entire range, that is, the linear relationship between the single cell voltage and the state of charge value of the battery is not strong; Figure 2 After differential processing, the obtained curve is as follows Figure 3 As shown, it expresses the change relationship of the static single cell voltage (V) of the lithium iron phosphate battery for every 1%. It can be seen Figure 3The curves shown in the figure are well distinguished in the high SOC section and the low SOC section, that is, the open circuit voltage of the battery changes significantly with the state of charge value, so it can be based on Figure 3 , and combined with the SOC accuracy requirements to determine whether the SOC value obtained by the actual open circuit voltage is valid.

[0097] In practical applications, taking ternary lithium batteries as an example, its SOC-OCV curve is as follows: Figure 4 As shown in the figure, it can be seen that the above curve has a slightly poor distinction only near 30% SOC, and the other parts are good, that is, the linear relationship between the open circuit voltage and the state of charge value of the battery is not strong only when the SOC is about 30%; Figure 4 After differential processing, the obtained curve is as follows Figure 5 As shown, it expresses the change relationship of the static single cell voltage (V) of the ternary lithium battery for every 1%. It can be seen Figure 5 The curve shown has a slightly poor distinction only when the SOC is around 30%, that is, only when the SOC value is around 30%, the open circuit voltage of the battery changes significantly with the SOC value, so it can be based on Figure 5 , and combined with the SOC accuracy requirements to determine whether the SOC value obtained by the actual open circuit voltage is valid.

[0098] Specifically, the above Figure 3 and Figure 5 If the static voltage correction error is 1%, the SOC accuracy requirement can be used to determine whether the SOC value obtained by the actual open circuit voltage is valid. For example, if the current BMS sampling error for the cell voltage is 3mV, it can be concluded that when the static cell voltage change corresponding to each 1% SOC is greater than 3mV, this section of actual open circuit voltage can be used to correct the SOC; and when the static cell voltage change corresponding to each 1% SOC is less than 3mV, this section of data cannot be used to correct the SOC.

[0099] It can be seen that the state of charge value correction method provided in the embodiment of the present application not only improves the probability of correcting the SOC, thereby improving the estimation accuracy of the SOC, but also the above method is suitable for correcting the state of charge value of different batteries, thereby improving the platform strategy of BMS static voltage correction.

[0100] Another object of the present invention is to provide a state of charge value correction system, which is applied to a vehicle, wherein the vehicle also includes a battery, wherein Figure 6 , Figure 6 A structural schematic diagram of a state of charge value correction system proposed in an embodiment of the present application is shown, and the system includes:

[0101] A first determination module 61, configured to determine an estimated state of charge value of a battery according to a preset state of charge value estimation method;

[0102] An acquisition module 62 is used to acquire a current open circuit voltage value of the battery;

[0103] A second determination module 63, configured to determine a corrected state of charge value corresponding to the current open circuit voltage value according to a state of charge and open circuit voltage relationship curve of the battery;

[0104] a third determination module 64, configured to determine a correlation strength value between the current open circuit voltage value and the state of charge value of the battery according to the state of charge and open circuit voltage relationship curve and the corrected state of charge value;

[0105] The correction module 65 is used to correct the estimated state of charge value according to the corrected state of charge value when the correlation strength value is greater than a correlation strength threshold.

[0106] In the system described in the embodiment of the present application, when the correlation strength value between the current open circuit voltage value of the battery and the state of charge value of the battery is greater than the correlation strength threshold, it means that the current open circuit voltage value is greatly affected by the state of charge value of the battery. At this time, the estimated state of charge value of the battery is corrected by querying the state of charge and open circuit voltage relationship curve through the current open circuit voltage value, and the corrected state of charge value is obtained. This can reduce or even avoid the state of charge value correction deviation caused by the sampling error of the open circuit voltage, avoid the problem of erroneous correction caused by the sampling error, and thus improve the accuracy of SOC correction.

[0107] Optionally, in the state of charge value correction system, the third determination module 64 includes:

[0108] A differential unit, used for performing differential processing on the relationship curve between the state of charge and the open circuit voltage of the battery to obtain a correlation strength curve between the state of charge and the open circuit voltage of the battery;

[0109] A determination unit is used to determine the correlation strength value according to the correlation strength curve and the corrected state of charge value.

[0110] Optionally, in the state of charge value correction system, the correction module 65 is specifically configured to replace the estimated state of charge value with the corrected state of charge value when the correlation strength value is greater than a correlation strength threshold.

[0111] Optionally, the state of charge value correction system further includes:

[0112] The discarding module is used to discard the modified state of charge value when the correlation strength value is less than or equal to the correlation strength threshold.

[0113] Another object of the present invention is to provide a vehicle, the vehicle comprising a battery, wherein the vehicle further comprises the above-mentioned state of charge value correction system.

[0114] The advantages of the state of charge value correction system, vehicle and the state of charge value correction method described above over the prior art are the same, and will not be described in detail here.

[0115] In summary, the state of charge value correction method, system and vehicle provided in the present application first determine the estimated state of charge value of the battery through a preset state of charge value estimation method, and obtain the current open circuit voltage value of the battery; then determine the corrected state of charge value corresponding to the above-mentioned current open circuit voltage value based on the battery state of charge and open circuit voltage relationship curve; then determine the correlation strength value between the above-mentioned current open circuit voltage value and the state of charge value of the above-mentioned battery based on the above-mentioned state of charge and open circuit voltage relationship curve and the above-mentioned corrected state of charge value; when the above-mentioned correlation strength value is greater than the correlation strength threshold, the above-mentioned estimated state of charge value is corrected according to the above-mentioned corrected state of charge value. Among them, when the correlation strength value between the current open circuit voltage value of the battery and the state of charge value of the battery is greater than the correlation strength threshold, it means that the current open circuit voltage value is greatly affected by the state of charge value of the battery. At this time, the estimated state of charge value of the battery is corrected by querying the state of charge and open circuit voltage relationship curve through the current open circuit voltage value, and the corrected state of charge value is obtained. This can reduce or even avoid the state of charge value correction deviation caused by the sampling error of the open circuit voltage, avoid the problem of erroneous correction caused by sampling error, and thus improve the accuracy of SOC correction.

[0116] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0118] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for correcting a state of charge value, characterized in that: The method comprises: Determining an estimated state of charge value of the battery according to an initial state of charge value of the battery and a charge and discharge current of the battery; Obtaining a current open circuit voltage value of the battery; Determining a corrected state of charge value corresponding to the current open circuit voltage value according to a state of charge and open circuit voltage relationship curve of the battery; Performing differentiation processing on the relationship curve between the state of charge and the open circuit voltage of the battery to obtain a correlation strength curve between the state of charge and the open circuit voltage of the battery; Determining a correlation strength value according to the correlation strength curve and the corrected state of charge value; In a case where the correlation strength value is greater than a correlation strength threshold, replacing the estimated state of charge value with the corrected state of charge value; In a case where the correlation strength value is less than or equal to the correlation strength threshold, determining the estimated state of charge value is a corrected state of charge value.

2. The method for correcting the state of charge value according to claim 1, characterized in that: The correlation strength threshold is greater than or equal to a sampling error of the open circuit voltage value.

3. The method for correcting the state of charge value according to claim 1, characterized in that: Determining the estimated state of charge value of the battery according to the initial state of charge value of the battery and the charge and discharge current of the battery includes: Integrate the time according to the charge and discharge current of the battery to determine the charge change; The estimated state of charge value is determined according to the charge change and the initial state of charge value.

4. The method for correcting the state of charge value according to claim 1, characterized in that: The obtaining of the current open circuit voltage value of the battery comprises: When the static time of the battery is greater than or equal to a preset time threshold, obtaining a static single cell voltage value of the battery; The current open circuit voltage value is determined according to each of the static cell voltage values.

5. A state of charge value correction system, characterized in that: The system comprises: A first determination module, configured to determine an estimated state of charge value of the battery according to an initial state of charge value of the battery and a charge and discharge current of the battery; An acquisition module, used for acquiring a current open circuit voltage value of the battery; A second determination module, configured to determine a corrected state of charge value corresponding to the current open circuit voltage value according to a state of charge and open circuit voltage relationship curve of the battery; A differential unit, used for performing differential processing on the relationship curve between the state of charge and the open circuit voltage of the battery to obtain a correlation strength curve between the state of charge and the open circuit voltage of the battery; a determination unit, configured to determine a correlation strength value according to the correlation strength curve and the corrected state of charge value; a third determining module, configured to replace the estimated state of charge value with the corrected state of charge value when the correlation strength value is greater than a correlation strength threshold; The second correction module is used to determine that the estimated state of charge value is a corrected state of charge value when the correlation strength value is less than or equal to the correlation strength threshold.

6. A vehicle, comprising a battery, characterized in that: The vehicle further comprises a state of charge value correction system as claimed in claim 5 .

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