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

Abstract

The present invention discloses a battery SOC estimation method, a battery management system and a computer-readable storage medium. The method comprises: obtaining the measured data of the battery, the measured data of the battery comprises: obtaining the measured data of the battery, the measured data of the battery comprises the measured current, the measured voltage, the measured SOC and the measured cumulative historical power; querying the correction data table according to the measured current and the measured voltage, obtaining the SOC upper limit correction data and the SOC lower limit correction data matching the measured current and the measured voltage; determining the SOC upper limit threshold and the SOC lower limit threshold according to the measured cumulative historical power, the SOC upper limit correction data and the SOC lower limit correction data; using the SOC upper limit threshold and the SOC lower limit threshold to correct the measured SOC and obtain the target SOC. The target SOC estimated by the battery SOC method has high accuracy and small error with the actual SOC of the battery, so that the SOC estimation can take into account the requirements of high accuracy, low resource requirements and high real-time performance.

Description

Technical Field

[0001] The present invention relates to the field of battery management technology, and in particular to a battery SOC estimation method, a battery management system and a computer-readable storage medium. Background Art

[0002] SOC (State Of Charge) refers to the ratio of the remaining dischargeable capacity of a battery after it has been used for a period of time or has been left unused for a long time to the capacity of the battery in its fully charged state. SOC is an important parameter of the entire battery energy storage system. Accurately estimating SOC can achieve reasonable utilization of battery energy, prevent unreasonable use of batteries such as overcharging or over-discharging, and thus increase the battery life.

[0003] Existing SOC estimation methods include but are not limited to the ampere-hour integration method, the real-time voltage correction method, the open circuit voltage method and the neural network method. Each SOC estimation method has its own advantages and disadvantages. The ampere-hour integration method realizes SOC estimation based on the accumulation of current. It is simple to operate and has low resource requirements, but it depends on the accuracy of the sampled current. The calibration requirements for the high voltage when full and the low voltage when empty are large, and the accuracy is low. The real-time voltage correction method estimates SOC based on the real-time voltage, real-time current and the known current charge and discharge voltage curves. When the voltage changes significantly or the battery is used frequently, the SOC can be accurately estimated with a small error. However, when the voltage changes are not obvious or the battery is used frequently, the accuracy of SOC estimation is low and the error is large. The open circuit voltage method is to measure the battery after it has been left stationary for several hours without charging or discharging, and use the open circuit voltage curve to estimate SOC. By leaving the battery stationary, current interference can be avoided and the accuracy of SOC estimation can be guaranteed, but the real-time performance is poor. The neural network method refers to the use of a neural network to calibrate and accumulate the battery data collected under different operating conditions to estimate SOC. It has high accuracy, but high resource requirements, but high operating condition data requirements. Summary of the invention

[0004] The embodiments of the present invention provide a battery SOC estimation method, a battery management system and a computer-readable storage medium to solve the problem that the existing SOC estimation method cannot take into account high accuracy, low operating resources and strong real-time performance.

[0005] An embodiment of the present invention provides a battery SOC estimation method, comprising:

[0006] Obtaining battery measured data, wherein the battery measured data includes measured current, measured voltage, measured SOC and measured accumulated historical power;

[0007] According to the measured current and the measured voltage, a correction data table is searched to obtain SOC upper limit correction data and SOC lower limit correction data matching the measured current and the measured voltage;

[0008] Determining an SOC upper limit threshold and an SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data;

[0009] The measured SOC is corrected using the SOC upper limit threshold and the SOC lower limit threshold to obtain a target SOC.

[0010] Preferably, the querying of the correction data table according to the measured current and the measured voltage to obtain the SOC upper limit correction data and the SOC lower limit correction data matching the measured current and the measured voltage includes:

[0011] Based on the measured current, a correction data table is searched to obtain SOC correction data to be selected in which a preset current in the correction data table matches the measured current;

[0012] Based on the measured voltage and the SOC correction data to be selected, acquiring the SOC upper limit correction data and the SOC lower limit correction data;

[0013] The SOC correction data to be selected include: preset current, preset voltage, preset SOC and preset accumulated historical power.

[0014] Preferably, the querying of the correction data table based on the measured current to obtain the SOC correction data to be selected in which the preset current in the correction data table matches the measured current includes:

[0015] If the preset current in the correction data table is equal to the measured current, the first correction data corresponding to the preset current is used as the SOC correction data to be selected;

[0016] If the preset current in the correction data table is not equal to the measured current, the second correction data and the third correction data in the correction data table are obtained, and based on the measured current, the second correction data and the third correction data, the SOC selected correction data is obtained, wherein the preset current in the second correction data is less than the measured current, and the preset current in the third correction data is greater than the measured current.

[0017] Preferably, the acquiring the SOC selected correction data based on the measured current, the second correction data and the third correction data comprises:

[0018] Processing the measured current, the second correction data and the third correction data using a data estimation formula to obtain the SOC correction data to be selected;

[0019] The data estimation formula is ST=(Sa-Sb)*(IT-Ib) / (Ia-Ib)+Sb; if Sa is the preset voltage in the second corrected data and Sb is the preset voltage in the third corrected data, then ST is the preset voltage in the SOC to be selected corrected data; if Sa is the preset SOC in the second corrected data and Sb is the preset SOC in the third corrected data, then ST is the preset SOC in the SOC to be selected corrected data; if Sa is the preset accumulated historical power in the second corrected data and Sb is the preset accumulated historical power in the third corrected data, then ST is the preset accumulated historical power in the SOC to be selected corrected data; IT is the measured current; Ia is the preset current in the second corrected data; Ib is the preset current in the third corrected data.

[0020] Preferably, the obtaining the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC selected correction data includes:

[0021] If the preset voltage in the SOC candidate correction data is greater than the measured voltage, a difference between the preset voltage and the measured voltage in the SOC candidate correction data is determined as a first difference, and the SOC candidate correction data with the smallest first difference is determined as the SOC upper limit correction data;

[0022] If the preset voltage in the SOC candidate correction data is less than the measured voltage, the difference between the measured voltage and the preset voltage in the SOC candidate correction data is determined as the second difference, and the SOC candidate correction data with the smallest second difference is determined as the SOC lower limit correction data.

[0023] Preferably, the determining of the SOC upper limit threshold and the SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data includes:

[0024] According to the measured cumulative historical power and the preset cumulative current error and the preset cumulative historical power in the SOC upper limit correction data, an upper limit error value is obtained, and a sum of the preset SOC in the SOC upper limit correction data and the upper limit error value is determined as the SOC upper limit threshold;

[0025] According to the measured cumulative historical power and the preset cumulative current error and the preset cumulative historical power in the SOC lower limit correction data, a lower limit error value is obtained, and the difference between the preset SOC in the SOC lower limit correction data and the lower limit error value is determined as the SOC lower limit threshold.

[0026] Preferably, the adopting the SOC upper limit threshold and the SOC lower limit threshold to correct the measured SOC to obtain the target SOC includes:

[0027] If the measured SOC is greater than the SOC upper limit threshold, determining the preset SOC in the SOC upper limit correction data as the target SOC;

[0028] If the measured SOC is less than the SOC lower limit threshold, determining the preset SOC in the SOC lower limit correction data as the target SOC;

[0029] If the measured SOC is not less than the SOC lower limit threshold and the measured SOC is not greater than the SOC upper limit threshold, the measured SOC is determined as the target SOC.

[0030] Preferably, the battery measured data also includes measured cumulative current error;

[0031] After obtaining the measured battery data, the battery SOC estimation method further includes:

[0032] comparing the measured cumulative current error with the current error tolerance value;

[0033] If the measured cumulative current error is greater than the current error tolerance value, querying the correction data table according to the measured current and the measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data that match the measured current and the measured voltage;

[0034] If the measured cumulative current error is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the battery measured data.

[0035] Preferably, the updating of the configuration correction data in the correction data table based on the battery measured data includes:

[0036] Acquire all the SOC preliminary correction data in the correction data table that match the preset SOC and the measured SOC, determine the SOC preliminary correction data that is adjacent to the preset current and the measured current as the first correction data to be updated and the second correction data to be updated, determine the first correction data to be updated and the second correction data to be updated as the SOC correction data to be updated, the preset current in the first correction data to be updated is less than the measured current, and the preset current in the second correction data to be updated is greater than the measured current;

[0037] Processing the battery measured data and the SOC to-be-updated correction data to obtain a measured unreliable value corresponding to the battery measured data and an unreliable value to-be-updated corresponding to the SOC to-be-updated correction data;

[0038] If the unreliable value to be updated is empty, or the actually measured unreliable value is smaller than the unreliable value to be updated, the SOC correction data to be updated is updated using the actually measured battery data.

[0039] Preferably, the processing of the battery measured data and the SOC to-be-updated correction data to obtain the measured unreliable value corresponding to the battery measured data and the to-be-updated unreliable value corresponding to the SOC to-be-updated correction data includes:

[0040] The measured unreliable value formula QT(CTBm)=ABS(IT-CTBm)*f+DT*g+(CT-CT)*h is used to calculate the measured data of the battery to obtain the measured unreliable value corresponding to the measured data of the battery;

[0041] The unreliable value to be updated formula Qn(CTBm)=ABS(In-CTBm)*f+Dn*g+(CT-Cn)*h is used to calculate the SOC corrected data to be updated and the battery measured data to obtain the unreliable value to be updated corresponding to the SOC corrected data to be updated;

[0042] Among them, QT (CTBm) is the measured unreliable value corresponding to the measured data of the battery; CTBm is the preset current; ABS is the absolute value function; IT, DT and CT are respectively the measured current, the measured cumulative current error and the measured cumulative historical power in the measured data of the battery; Qn (CTBm) is the unreliable value to be updated corresponding to the SOC correction data to be updated; In, Dn and Cn are respectively the preset current, the preset cumulative current error and the preset cumulative historical power corresponding to the SOC correction data to be updated; f is the current coefficient; g is the cumulative current error coefficient; h is the cumulative historical power coefficient.

[0043] An embodiment of the present invention further provides a battery management system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the battery SOC estimation method as described above when executing the computer program.

[0044] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the battery SOC estimation method as described above is implemented.

[0045] The battery SOC estimation method, battery management system and computer-readable storage medium query the correction data table according to the measured current and the measured voltage, and quickly determine the SOC upper limit correction data and the SOC lower limit correction data, so that the SOC estimation requires low resources and helps to provide real-time SOC estimation; then determine the SOC upper limit threshold and the SOC lower limit threshold based on the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data, and use the SOC upper limit threshold and the SOC lower limit threshold evaluation to correct the measured SOC, so that the output target SOC has high accuracy and a small error with the actual SOC of the battery, so that the SOC estimation can take into account the requirements of high accuracy, low resource requirements and high real-time performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0047] Figure 1 is a flow chart of a battery SOC estimation method according to an embodiment of the present invention;

[0048] Figure 2 is another flow chart of a battery SOC estimation method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The battery SOC estimation method provided by the embodiment of the present invention can be applied in a battery management system (BMS), which is connected to a battery and is used to estimate the SOC of the battery so that the estimated target SOC has the advantages of high accuracy, low resource requirements and high real-time performance.

[0051] In this embodiment, a correction data table is pre-stored in the memory of the BMS, and the correction data table is a data table that pre-records different configuration correction data. The configuration correction data refers to data that is formed and recorded in the memory of the BMS according to the battery operating conditions before the system time of obtaining the actual battery data, and can be understood as the data required to be called for realizing the estimation and correction of the actual measured SOC.

[0052] Since the storage resources in the BMS are limited, the configuration correction data in the correction data table are limited. According to the storage resources provided by the BMS, X*Y configuration correction data can be stored in the correction data table, where X is the number of preset SOCs. For example, if the preset SOC values ​​are 5%, 15%, 25%, 75%, 85% and 95%, X is 6; Y is the number of preset currents. If the preset current values ​​are 0.2C, 0.5C, 0.9C, 1C and 2.2C, Y is 5, and 30 configuration correction data are stored in the correction data table.

[0053] As an example, based on the test data generated by the battery during the test operation, X voltage-current measured curves corresponding to the preset SOC are drawn in advance, and then Y preset currents are determined according to the current sampling rule, so as to determine the preset voltage according to the preset current and the voltage-current measured curve. In this example, the Y preset currents can be determined by the arithmetic difference number acquisition rule to minimize the difference to help reduce the error of subsequent SOC estimation. At this time, the Y preset currents are the preset currents CTBm, where 1≦m≦Y; as shown above, the preset currents CTB1=0.2, CTB2=0.7, CTB3=1.2, CTB4=1.7, and CTB5=2.2.

[0054] In this example, the configuration correction data includes a preset current, a preset voltage, a preset SOC, a preset cumulative current error, and a preset cumulative historical power. The nth configuration correction data can be represented by [SOCn, In, Vn, Dn, Cn], where 1≦n≦X*Y. The preset SOC is the SOC of the battery that may need to be corrected in advance, which can be represented by SOCn. The preset current refers to the current of the battery working process that may need to be corrected in advance, which can be represented by In, and can be specifically a charging current or a discharging current. The preset voltage refers to the voltage required for realizing the SOC estimation correction formed and recorded before the system time when the battery measured data is received, which can be represented by Vn. The preset cumulative current error refers to the accumulation of all error currents before the system time when the battery measured data is received, which can be represented by Dn. The preset cumulative historical power refers to the accumulation of all power before the system time when the battery measured data is received, which can be represented by Cn. For example, when the real-time voltage correction method is used to estimate the SOC, the preset SOC, preset current, and preset voltage are specific sampling points in the known current charge and discharge voltage curves.

[0055] In one embodiment, if Figure 1 As shown, a battery SOC estimation method is provided, and the method is applied to a BMS as an example for explanation, including the following steps:

[0056] S11: Obtaining battery measured data, the battery measured data includes measured current, measured voltage, measured SOC and measured accumulated historical power.

[0057] The measured battery data refers to the battery-related data obtained by the BMS in real time. The measured current refers to the current obtained by the BMS during the battery working process, which can be expressed as I T It can be understood as the current determined by the SOC algorithm method, which can be the charging current or the discharging current. The measured voltage refers to the voltage of the battery during operation obtained by the BMS in real time, which can be expressed as V T It can be understood as the voltage determined when the SOC algorithm is used for processing. The measured SOC is the SOC of the battery obtained by the BMS in real time. T It can be understood as the estimated SOC determined by the SOC estimation method. The measured cumulative historical power is the accumulation of all power after receiving the measured data of the battery, which can be used to calculate the power consumption. T For example, during battery charging, the measured cumulative historical power is the accumulation of all charging power; during battery discharging, the measured cumulative historical power is the accumulation of all discharging power. It can be understood that the measured cumulative historical power includes the accumulation of all cumulative historical power before the system time and the power in the current battery measured data.

[0058] As an example, the BMS obtains the measured battery data in real time. The measured battery data includes the measured current, measured voltage, measured SOC, measured cumulative current error and measured cumulative historical power. [SOC T ,I T 、V T , D T , C T ] represents the measured data of the battery. For example, during the battery charging process, when the measured current of 1.2C is used to charge to the measured voltage V0, the real-time voltage correction method can be used to estimate the SOC of the measured current 1.2C and the measured voltage V0 to obtain the measured SOC0, and the measured cumulative current error D0 and the measured cumulative historical power C0 are calculated in combination with the configuration correction data to obtain the measured battery data [SOC0, 1.2C, V0, D0, C0].

[0059] S12: querying a correction data table according to the actual measured current and the actual measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data that match the actual measured current and the actual measured voltage.

[0060] When the real-time voltage correction method is used for SOC estimation, when the SOC is in the middle segment (such as 30%-70%), the SOC estimation accuracy is higher, and the error between the estimated measured SOC and the actual SOC of the battery is smaller; when the SOC is in the low segment (such as 0-30%) or high segment (such as 70%-100%), the SOC estimation accuracy is lower, and the error between the estimated measured SOC and the actual SOC of the battery is larger, and correction is required. Therefore, it is necessary to query the correction data table according to the measured current and the measured voltage to obtain the SOC upper limit correction data and the SOC lower limit correction data that match the measured current and the measured voltage, so as to use the SOC upper limit correction data and the SOC lower limit correction data for correction.

[0061] The correction data table is a data table that pre-records different configuration correction data. The configuration correction data refers to the data that is formed according to the battery operating conditions and recorded in the memory of the BMS before the system time of obtaining the actual battery data. It can be understood as the data needed to implement the estimated correction of the measured SOC. Generally speaking, the configuration correction data can be understood as that when the preset current and preset voltage are met, the corresponding measured SOC should be within the error range of its preset SOC, so as to correct the measured SOC, ensure that the error between the target SOC determined after correction and the actual SOC of the battery is small, and improve the accuracy of the target SOC. For example, when the preset current is 1.2C, the configuration correction data with a preset current of 1.2C stored in the correction data table is as follows:

[0062] [5%, 1.2C, V1, D1, C1]

[0063] [15%, 1.2C, V2, D2, C2]

[0064] [25%, 1.2C, V3, D3, C3]

[0065] [75%, 1.2C, V4, D4, C4]

[0066] [85%, 1.2C, V5, D5, C5]

[0067] [95%, 1.2C, V6, D6, C6]

[0068] The SOC upper limit correction data is configuration correction data for correcting the upper limit of the measured SOC. The SOC lower limit correction data is configuration correction data for correcting the lower limit of the measured SOC.

[0069] As an example, after receiving the measured data of the battery, the BMS needs to query the pre-stored correction data table based on the measured current and measured voltage, and select the configuration correction data whose preset current matches the measured current and whose preset voltage matches the measured voltage to determine as the SOC upper limit correction data and the SOC lower limit correction data. In this example, the BMS can select the configuration correction data whose preset voltage is closest to the measured voltage from all the configuration correction data whose preset current matches the measured current and whose preset voltage is greater than the measured voltage to determine as the SOC upper limit correction data; and select the configuration correction data whose preset voltage is closest to the measured voltage from all the configuration correction data whose preset current matches the measured current and whose preset voltage is less than the measured voltage to determine as the SOC lower limit correction data.

[0070] S13: Determine the SOC upper limit threshold and the SOC lower limit threshold according to the measured cumulative historical power, the SOC upper limit correction data and the SOC lower limit correction data.

[0071] The SOC upper limit threshold is an evaluation threshold used to compare and determine whether the upper limit of the measured SOC needs to be corrected. The SOC lower limit threshold is an evaluation threshold used to compare and determine whether the lower limit of the measured SOC needs to be corrected.

[0072] As an example, the BMS executes the threshold determination logic, processes the SOC upper limit correction data, and obtains the SOC upper limit threshold; processes the SOC lower limit correction data, and obtains the SOC lower limit threshold. It is understandable that since both the SOC upper limit correction data and the SOC lower limit correction data include not only the preset current and the preset voltage, but also the preset SOC, the preset cumulative current error, and the preset cumulative historical power; the BMS can execute the threshold determination logic in real time, process the measured cumulative historical power and the preset SOC, the preset cumulative current error, and the preset cumulative historical power in the SOC upper limit correction data, and determine the SOC upper limit threshold; execute the threshold determination logic in real time, process the measured cumulative historical power and the preset SOC, the preset cumulative current error, and the preset cumulative historical power in the SOC lower limit correction data, and determine the SOC lower limit threshold. In this example, the threshold determination logic refers to the logic that uses the measured cumulative historical power, the preset SOC, the preset cumulative current error, and the preset cumulative historical power as input parameters, and uses pre-configured operation rules for processing.

[0073] S14: Correct the measured SOC using the SOC upper threshold and the SOC lower threshold to obtain the target SOC.

[0074] The target SOC is the target SOC determined after correcting the measured SOC using the SOC upper threshold and the SOC lower threshold. The target SOC is the final SOC with the smallest error with the actual SOC of the battery and the highest accuracy.

[0075] As an example, after determining the SOC upper limit threshold and the SOC lower limit threshold, the BMS may use the pre-configured SOC correction logic to compare the measured SOC with the SOC upper limit threshold and the SOC lower limit threshold, so as to determine whether the measured SOC needs to be corrected according to the comparison result of the measured SOC with the SOC lower limit threshold and the SOC upper limit threshold, and how to correct the measured SOC in detail if it is determined that the measured SOC needs to be corrected. For example, when the measured SOC is not between the SOC lower limit threshold and the SOC upper limit threshold, the SOC compensation rule may be used to compensate for the measured SOC less than the SOC lower limit threshold, or to compensate for the measured SOC greater than the SOC upper limit threshold, so that the target SOC determined after compensation is closer to the range of the SOC lower limit threshold and the SOC upper limit threshold, thereby ensuring that the error between the target SOC and the actual SOC of the battery is minimized and the accuracy is maximized. The SOC compensation rule is a pre-set rule for compensating the measured SOC. Different compensation conditions and compensation formulas corresponding to each compensation condition can be configured in the SOC compensation rule to determine the corresponding compensation condition according to the actual situation, thereby adopting the corresponding compensation formula for processing.

[0076] The battery SOC estimation method provided in the present embodiment queries the correction data table according to the measured current and the measured voltage, and quickly determines the SOC upper limit correction data and the SOC lower limit correction data, so that the SOC estimation requires low resources and helps to provide real-time SOC estimation; then the SOC upper limit threshold and the SOC lower limit threshold are determined based on the measured cumulative historical power, the SOC upper limit correction data and the SOC lower limit correction data, and the SOC upper limit threshold and the SOC lower limit threshold are used to evaluate and correct the measured SOC, so that the output target SOC has high accuracy and a small error with the actual SOC of the battery, so that the SOC estimation can take into account the requirements of high accuracy, low resource requirements and high real-time performance.

[0077] In one embodiment, step S12, i.e., querying a correction data table according to the measured current and the measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data matching the measured current and the measured voltage, includes:

[0078] S121: querying a correction data table based on the actual current, and obtaining SOC correction data to be selected in which a preset current in the correction data table matches the actual current.

[0079] S122: Based on the measured voltage and the SOC correction data to be selected, obtain SOC upper limit correction data and SOC lower limit correction data.

[0080] The SOC correction data to be selected include: preset current, preset voltage, preset SOC and preset accumulated historical power.

[0081] The SOC correction data to be selected refers to the configuration correction data that matches the preset current with the measured current, that is, all configuration correction data corresponding to the preset current that matches the measured current are determined as the SOC correction data to be selected. In this example, the preset current that matches the measured current can refer to a preset current that is equal to the measured current, or a preset current that is not equal to the measured current but is closest to the measured current.

[0082] As an example, if the measured battery data is [SOC0, 1.2C, V0, D0, C0], when the measured current is 1.2C, all the configuration correction data corresponding to the preset current of 1.2C in the correction data table are obtained and determined as the SOC candidate correction data. For example, the SOC candidate correction data is as follows:

[0083] [5%, 1.2C, V1, D1, C1]

[0084] [15%, 1.2C, V2, D2, C2]

[0085] [25%, 1.2C, V3, D3, C3]

[0086] [75%, 1.2C, V4, D4, C4]

[0087] [85%, 1.2C, V5, D5, C5]

[0088] [95%, 1.2C, V6, D6, C6]

[0089] In the above-mentioned SOC candidate correction data, when the preset current matches the measured current, the preset voltage is proportional to the preset SOC, that is, the larger the preset voltage is, the larger the preset SOC is.

[0090] It can be understood that the preset voltages and the measured voltages in all SOC candidate correction data that match the preset current and the measured current can be processed in ascending or descending order to form a voltage sorting sequence, and the SOC candidate correction data corresponding to two preset voltages adjacent to the measured voltage in the voltage sorting sequence can be respectively determined as SOC upper limit correction data and SOC lower limit correction data, so as to realize the correction of the upper limit or lower limit of the measured SOC by using the SOC upper limit correction data and the SOC lower limit correction data, thereby ensuring the accuracy of the target SOC finally determined and reducing the error between the target SOC and the actual SOC of the battery.

[0091] In one embodiment, step S121, i.e., querying the correction data table based on the measured current to obtain the SOC correction data to be selected in which the preset current in the correction data table matches the measured current, includes:

[0092] S1211: If the preset current in the correction data table is equal to the actual measured current, the first correction data corresponding to the preset current is used as the SOC correction data to be selected.

[0093] S1212: If the preset current in the correction data table is not equal to the measured current, obtain the second correction data and the third correction data in the correction data table, and obtain the SOC selected correction data based on the measured current, the second correction data and the third correction data, wherein the preset current in the second correction data is less than the measured current, and the preset current in the third correction data is greater than the measured current.

[0094] As an example, the BMS obtains the measured battery data in real time. The measured battery data includes the measured current, measured voltage, measured SOC, measured cumulative current error and measured cumulative historical power. [SOC T ,I T 、V T , D T , C T] represents the measured data of the battery. For example, during the battery charging process, when the measured current of 1.2C is used to charge to the measured voltage V0, the real-time voltage correction method can be used to estimate the SOC of the measured current 1.2C and the measured voltage V0 to obtain the measured SOC0, and the measured cumulative current error D0 and the measured cumulative historical power C0 are calculated in combination with the configuration correction data to obtain the measured battery data [SOC0, 1.2C, V0, D0, C0].

[0095] As an example, the measured current can be compared with the preset current in all the configuration correction data in the correction data table. If the preset current is equal to the measured current, the configuration correction data in which the preset current is equal to the measured current is determined as the first correction data, and the first correction data is the SOC correction data to be selected. If the preset current is not equal to the measured current, the measured current and the preset current in all the configuration correction data are sorted to obtain a current sorting sequence, and the two configuration correction data adjacent to the measured current are respectively determined as the second correction data and the third correction data. For example, among the two preset currents adjacent to the measured current in the current sorting sequence, the configuration correction data in which the preset current is less than the measured current is determined as the second correction data; and among the two preset currents adjacent to the measured current in the current sorting sequence, the configuration correction data in which the preset current is greater than the measured current is determined as the third correction data.

[0096] In one embodiment, step S1212, i.e., obtaining SOC selected correction data based on the measured current, the second correction data and the third correction data, includes: using a data estimation formula to process the measured current, the second correction data and the third correction data to obtain the SOC selected correction data.

[0097] The data estimation formula is ST=(Sa-Sb)*(IT-Ib) / (Ia-Ib)+Sb; if Sa is the preset voltage in the second correction data, Sb is the preset voltage in the third correction data, then ST is the preset voltage in the SOC correction data to be selected; if Sa is the preset SOC in the second correction data, Sb is the preset SOC in the third correction data, then ST is the preset SOC in the SOC correction data to be selected; if Sa is the preset accumulated historical power in the second correction data, Sb is the preset accumulated historical power in the third correction data, then ST is the preset accumulated historical power in the SOC correction data to be selected; I T is the measured current; Ia is the preset current in the second correction data; Ib is the preset current in the third correction data.

[0098] In this embodiment, the BMS can directly determine the measured current as the measured current, and after determining the second correction data and the third correction data, it can use the specific values ​​of the preset current, preset voltage, preset cumulative current error and preset cumulative historical power in the second correction data and the third correction data to process with the measured current to determine the SOC selected correction data.

[0099] As an example, the BMS uses a data estimation formula to process the measured current and the second correction data and the third correction data to obtain the SOC correction data to be selected; wherein the data estimation formula is ST=(Sa-Sb)*(IT-Ib) / (Ia-Ib)+Sb; if Sa is the preset voltage in the second correction data, and Sb is the preset voltage in the third correction data, then ST is the preset voltage in the SOC correction data to be selected; if Sa is the preset SOC in the second correction data, and Sb is the preset SOC in the third correction data, then ST is the preset SOC in the SOC correction data to be selected; if Sa is the preset accumulated historical power in the second correction data, and Sb is the preset accumulated historical power in the third correction data, then ST is the preset accumulated historical power in the SOC correction data to be selected; I T is the measured current; Ia is the preset current in the second correction data; Ib is the preset current in the third correction data.

[0100] For example, the second correction data [SOCa, Ia, Va, Da, Ca] is [75%, 1.3C, 3.458, 5AH, 30000AH], the third correction data [SOCb, Ib, Vb, Db, Cb] is [75%, 1.0C, 3.412, 6AH, 22000AH], and the measured current I T =1.2C, the measured voltage estimation formula is V T =(Va-Vb)*

[0101] (I0-Ib) / (Ia-Ib)+Vb=(3.458-3.412)*(1.2-1.0) / (1.3-1.0)+3.412=3.443, that is, the measured voltage V T is 3.443; the formula for the measured cumulative current error is D T =(Da-Db)*(I0-Ib) / (Ia-Ib)+Db=(5-6)*(1.2-1.0) / (1.3-1.0)+6=5.33; Actual measured cumulative current error D T The formula for the measured cumulative historical power is C T =(Ca-Cb)*(I0-Ib) / (Ia-Ib)+Cb=(30000-22000)*(1.2-1.0) / (1.3-1.0)+22000=27333, i.e. the measured cumulative historical electricity CT is 27333, then the final measured battery data is [75%, 1.2C, 3.443, 5.33AH, 27333AH].

[0102] Furthermore, the measured data of the battery also includes the measured cumulative current error; accordingly, the SOC selected correction data also includes the preset cumulative current error, then the second correction data and the third correction data also include the preset cumulative current error, then the BMS uses the data estimation formula to process the measured current and the second correction data and the third correction data to obtain the SOC selected correction data; wherein the data estimation formula is ST=(Sa-Sb)*(IT-Ib) / (Ia-Ib)+Sb; if Sa is the preset cumulative current error in the second correction data, Sb is the preset cumulative current error in the third correction data, then ST is the preset cumulative current error in the SOC selected correction data; I T is the measured current; Ia is the preset current in the second correction data; Ib is the preset current in the third correction data.

[0103] The battery SOC estimation method provided in this embodiment can quickly determine the SOC candidate correction data based on the measured current, the second correction data and the third correction data, so as to use the obtained SOC candidate correction data to perform estimated SOC correction, thereby ensuring the accuracy of the final target SOC and reducing the error with the actual SOC.

[0104] In one embodiment, step S122, i.e., obtaining SOC upper limit correction data and SOC lower limit correction data based on the measured voltage and the SOC candidate correction data, includes:

[0105] S1221: If the preset voltage in the SOC correction data to be selected is greater than the measured voltage, the difference between the preset voltage and the measured voltage in the SOC correction data to be selected is determined as the first difference, and the SOC correction data to be selected with the smallest first difference is determined as the SOC upper limit correction data.

[0106] S1222: If the preset voltage in the SOC candidate correction data is lower than the measured voltage, the difference between the measured voltage and the preset voltage in the SOC candidate correction data is determined as the second difference, and the SOC candidate correction data with the smallest second difference is determined as the SOC lower limit correction data.

[0107] As an example, if the measured battery data is [SOC0, 1.2C, V0, D0, C0], when the measured current is 1.2C, all the configuration correction data corresponding to the preset current of 1.2C in the correction data table are obtained and determined as the SOC candidate correction data. For example, the SOC candidate correction data is as follows:

[0108] [5%, 1.2C, V1, D1, C1]

[0109] [15%, 1.2C, V2, D2, C2]

[0110] [25%, 1.2C, V3, D3, C3]

[0111] [75%, 1.2C, V4, D4, C4]

[0112] [85%, 1.2C, V5, D5, C5]

[0113] [95%, 1.2C, V6, D6, C6]

[0114] In the above-mentioned SOC candidate correction data, when the preset current matches the measured current, the preset voltage is proportional to the preset SOC, that is, the larger the preset voltage is, the larger the preset SOC is.

[0115] As an example, the measured voltage V0 is compared with the preset voltages V1, V2, V3, V4, V5 and V6. If the preset voltages V5 and V6 are greater than the measured voltage V0, at this time, the difference between the preset voltage V5 and the measured voltage V0 can be calculated and determined as the first difference V5-V0, and the difference between the preset voltage V6 and the measured voltage V0 can be calculated and determined as the first difference V6-V0; then the first difference V5-V0 is compared with V6-V0. Since the first difference V5-V0 is less than the first difference V6-V0, the SOC candidate correction data [85%, 1.2C, V5, D5, C5] corresponding to the first difference V5-V0 can be determined as the SOC upper limit correction data. If the preset voltages V1, V2, V3 and V4 are all lower than the measured voltage V0, the second differences V0-V1, V0-V2, V0-V3 and V0-V4 between the measured voltage V0 and the preset voltages V1, V2, V3 and V4 are calculated respectively. Since V0-V4 is the smallest, the SOC selected correction data [75%, 1.2C, V4, D4, C4] corresponding to the second difference V0-V4 can be determined as the SOC lower limit correction data.

[0116] It can be understood that the preset voltages and the measured voltages in all SOC candidate correction data that match the preset current and the measured current can be processed in ascending or descending order to form a voltage sorting sequence, and the SOC candidate correction data corresponding to two preset voltages adjacent to the measured voltage in the voltage sorting sequence can be respectively determined as SOC upper limit correction data and SOC lower limit correction data, so as to realize the correction of the upper limit or lower limit of the measured SOC by using the SOC upper limit correction data and the SOC lower limit correction data, thereby ensuring the accuracy of the target SOC finally determined and reducing the error between the target SOC and the actual SOC of the battery.

[0117] In one embodiment, step S13, i.e., determining the SOC upper limit threshold and the SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data, includes:

[0118] S131: Obtain an upper limit error value based on the measured cumulative historical power and the preset cumulative current error and preset cumulative historical power in the SOC upper limit correction data, and determine the sum of the preset SOC in the SOC upper limit correction data and the upper limit error value as the SOC upper limit threshold.

[0119] S132: Obtain a lower limit error value based on the measured cumulative historical power and the preset cumulative current error and the preset cumulative historical power in the SOC lower limit correction data, and determine the difference between the preset SOC in the SOC lower limit correction data and the lower limit error value as the SOC lower limit threshold.

[0120] As an example, the BMS first uses the upper limit error value calculation formula to process the preset cumulative current error and the preset cumulative historical power in the measured cumulative historical power and SOC upper limit correction data to obtain the upper limit error value. The upper limit error value calculation formula is Wu=Du+k*(C T -Cu), C T For the measured cumulative historical power, Du and Cu are the preset cumulative current error and preset cumulative historical power in the SOC upper limit correction data, respectively, Wu is the upper limit error value, and k is the cumulative historical power attenuation coefficient. The cumulative historical power attenuation coefficient k can be obtained based on the battery cycle attenuation experimental data. For example, in the SOC upper limit correction data [85%, 1.2C, V5, D5, C5], the value of Du is D5 and the value of Cu is C5. Then, the BMS determines the sum of the preset SOCu in the SOC upper limit correction data and the upper limit error value Wu as the SOC upper limit threshold to limit the upper limit error corresponding to the preset SOCu, that is, the upper limit error acceptable to the preset SOCu.

[0121] As an example, the BMS first uses the lower limit error value calculation formula to process the preset cumulative current error and the preset cumulative historical power in the measured cumulative historical power and SOC lower limit correction data to obtain the lower limit error value. The lower limit error value calculation formula is Wp=Dp+k*(C T -Cp), C TTo measure the accumulated historical power, Dp and Cp are the preset accumulated current error and the preset accumulated historical power in the SOC lower limit correction data, respectively. Wp is the lower limit error value, and k is the accumulated historical power attenuation coefficient. The accumulated historical power attenuation coefficient k can be obtained based on the battery cycle attenuation experimental data. For example, in the SOC lower limit correction data [75%, 1.2C, V4, D4, C4], the value of Dp is D4, and the value of Cp is C4. Then, the BMS determines the sum of the preset SOCp in the SOC lower limit correction data and the lower limit error value Wp as the SOC lower limit threshold to limit the lower limit of the error corresponding to the preset SOCp, that is, the lower limit of the error that the preset SOCp can accept.

[0122] In one embodiment, step S14, i.e., using the SOC upper limit threshold and the SOC lower limit threshold to correct the measured SOC to obtain the target SOC, includes:

[0123] S141: If the measured SOC is greater than the SOC upper limit threshold, the preset SOC in the SOC upper limit correction data is determined as the target SOC.

[0124] S142: If the measured SOC is less than the SOC lower limit threshold, the preset SOC in the SOC lower limit correction data is determined as the target SOC.

[0125] S143: If the measured SOC is not less than the SOC lower limit threshold and the measured SOC is not greater than the SOC upper limit threshold, the measured SOC is determined as the target SOC.

[0126] As an example, if the measured SOC is greater than the SOC upper limit threshold, it means that the measured SOC is greater than the acceptable upper limit error of the preset SOCu in the SOC upper limit correction data. At this time, the measured SOC is directly corrected to the preset SOCu in the SOC upper limit correction data, that is, the preset SOCu in the SOC upper limit correction data is directly determined as the target SOC to avoid excessive error between the target SOC and the actual SOC of the battery. For example, the preset SOCu in the SOC upper limit correction data [85%, 1.2C, V5, D5, C5] is 85%, and the upper limit error value is 2%, then the SOC upper limit threshold is 87%. If the measured SOC T is 88%, the preset SOCu in the SOC upper limit correction data is determined as the target SOC, that is, the target SOC is 85%.

[0127] As an example, if the measured SOC is less than the SOC lower limit threshold, it means that the measured SOC is less than the acceptable lower limit of the error of the preset SOCp in the SOC lower limit correction data. At this time, the measured SOC is directly corrected to the preset SOCp in the SOC lower limit correction data, that is, the preset SOCp in the SOC lower limit correction data is directly determined as the target SOC to avoid excessive error between the target SOC and the actual SOC of the battery. For example, the preset SOCp in the SOC lower limit correction data [75%, 1.2C, V4, D4, C4] is 75%, the lower limit error value is 2%, the SOC lower limit threshold is 73%, and the SOC T is 71%, then the preset SOCp in the SOC lower limit correction data is determined as the target SOC, and the target SOC is 75%.

[0128] As an example, if the measured SOC is not less than the SOC lower limit threshold, and the measured SOC is not greater than the SOC upper limit threshold, it means that the measured SOC is not less than the acceptable lower limit of the error of the preset SOCp in the SOC lower limit correction data, and the measured SOC is not greater than the acceptable upper limit of the error of the preset SOCu in the SOC upper limit correction data, then the measured SOC is directly determined as the target SOC, which can ensure the accuracy of the target SOC and make the error between it and the actual SOC of the battery smaller. For example, when the SOC lower limit threshold is 73% and the SOC upper limit threshold is 87%, if the measured SOC is 80%, since 73%<80%<87%, the measured SOC is directly determined as the target SOC, that is, the target SOC is 80%, and no correction is required.

[0129] The battery SOC estimation method provided in the present embodiment queries the correction data table according to the measured current and the measured voltage in the battery measured data, and quickly determines the SOC upper limit correction data and the SOC lower limit correction data from the limited configuration correction data, so that the SOC estimation requires low resources and helps to provide the real-time performance of the SOC estimation; then the SOC upper limit threshold and the SOC lower limit threshold are determined based on the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data, and the measured SOC is corrected by using the SOC upper limit threshold and the SOC lower limit threshold evaluation, so that the output target SOC has high accuracy and a small error with the actual SOC of the battery, so that the SOC estimation can take into account the requirements of high accuracy, low resource requirements and high real-time performance.

[0130] In one embodiment, the measured battery data also includes the measured cumulative current error. Figure 2 As shown, after step S11, that is, after obtaining the battery measured data, the battery SOC estimation method further includes:

[0131] S21: Compare the measured cumulative current error and the current error tolerance value.

[0132] S22: If the measured cumulative current error is greater than the current error tolerance value, query the correction data table according to the measured current and the measured voltage to obtain the SOC upper limit correction data and the SOC lower limit correction data that match the measured current and the measured voltage.

[0133] S23: If the measured cumulative current error is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the battery measured data.

[0134] Furthermore, the measured battery data also includes the measured cumulative current error. The measured cumulative current error refers to the accumulation of all error currents after receiving the measured battery data, which can be calculated using D T In general, the measured cumulative current error is re-counted after each full or emptying, and is the accumulation of all error charges counted after full or emptying. It can be understood that the measured cumulative current error includes the sum of all error charges before the system time and the accumulation of the error charge formed by the current battery measured data. The error charge here can be understood as the error between the measured SOC and the actual SOC of the battery.

[0135] The current error tolerance value is a pre-configured threshold value for evaluating whether the configuration correction data in the correction data table needs to be updated. For example, the current error tolerance value may be 2% of the battery power.

[0136] As an example, the BMS will compare the measured cumulative current error with the preset current error tolerance value; if the measured cumulative current error is greater than the current error tolerance value, steps S12-S14 are executed to correct the measured SOC and output the target SOC to ensure the accuracy of the target SOC; if the measured cumulative current error is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the measured battery data to update the configuration correction data in the correction data table according to the actual operating conditions of the battery to ensure the accuracy and real-time nature of the configuration correction data in the correction data table.

[0137] In this embodiment, since the physical condition of the battery changes in real time during the actual operation of the battery, such as battery aging, reduction in total battery capacity, or abnormal increase in internal resistance, the configuration correction data in the correction data table stored in the memory of the BMS at the factory reduces the accuracy of SOC estimation for batteries with changed physical conditions. When the measured cumulative current error in the battery measured data is not greater than the current error tolerance value, updating the configuration correction data in the correction data table based on the battery measured data helps to improve the accuracy of SOC estimation correction for subsequently acquired battery measured data.

[0138] Since the current value can be used to evaluate the index of reducing the maximum difference, the cumulative current error is an index used to evaluate the deviation between the historical current and the preset current. The cumulative historical power is equivalent to the time validity of the record, and its unreliability will increase with the increase of the battery power; therefore, based on the measured current, the measured cumulative current error and the measured cumulative historical power in the battery measured data, the unreliability of different preset currents in all configuration correction data with the same preset SOC and measured SOC can be calculated to obtain the measured unreliable value of the battery measured data, and determine whether it is necessary to use the battery measured data to update the configuration correction data in the correction data table based on the measured unreliable value.

[0139] In one embodiment, the measured battery data includes the measured SOC, the measured current, the measured voltage, the measured cumulative current error and the measured cumulative historical power, which can be expressed as [SOC T ,I T 、V T , D T , C T ]; the configuration correction data includes the preset current, preset voltage, preset SOC, preset cumulative current error and preset cumulative historical power, which can be represented by [SOCn, In, Vn, Dn, Cn]. Step S23, that is, updating the configuration correction data in the correction data table based on the battery measured data, includes:

[0140] S231: Obtain the SOC preliminary correction data that matches all preset SOCs and the measured SOCs in the correction data table, determine the SOC preliminary correction data whose preset current is adjacent to the measured current as the first correction data to be updated and the second correction data to be updated, determine the first correction data to be updated and the second correction data to be updated as the SOC correction data to be updated, the preset current in the first correction data to be updated is smaller than the measured current, and the preset current in the second correction data to be updated is larger than the measured current.

[0141] S232: Process the battery measured data and the SOC to-be-updated correction data to obtain a measured unreliable value corresponding to the battery measured data and an unreliable value to-be-updated corresponding to the SOC to-be-updated correction data.

[0142] S233: If the measured unreliable value is smaller than the unreliable value to be updated, the SOC correction data to be updated is updated using the measured battery data.

[0143] As an example, step S231 specifically includes: (1) first comparing the preset SOCs in all configuration correction data in the correction data table, and determining the configuration correction data that matches the preset SOC with the measured SOC as the SOC preliminary correction data. For example, the configuration correction data that equals the preset SOC to the measured SOC is determined as the SOC preliminary correction data, or the configuration correction data that is closest to the preset SOC and the measured SOC is determined as the SOC preliminary correction data. (2) Then, the SOC preliminary correction data that is close to the preset current and the measured current is determined as the SOC screening correction data. For example, the preset current and the measured current in all the SOC preliminary correction data are sorted to form a current sorting sequence, and the SOC preliminary correction data corresponding to the two preset currents adjacent to the measured current in the current sorting sequence, that is, the SOC preliminary correction data corresponding to the two preset currents before and after the measured current in the current sorting sequence, are respectively determined as the first correction data to be updated and the second correction data to be updated, and the first correction data to be updated and the second correction data to be updated are determined as SOC screening correction data, so that it is subsequently determined whether the SOC correction data to be updated needs to be updated according to the battery measured data and the SOC correction data to be updated, which helps to ensure the accuracy of the subsequent battery SOC estimation algorithm. Among them, the preset current in the first correction data to be updated is less than the measured current, that is, among all the preset currents less than the measured current, the SOC preliminary correction data corresponding to the preset current with the smallest difference with the measured current is the first correction data to be updated. The preset current in the second correction data to be updated is greater than the measured current, that is, among all the preset currents greater than the measured current, the SOC preliminary correction data corresponding to the preset current with the smallest difference with the measured current is the second correction data to be updated.

[0144] As an example, step S232 specifically includes: using an unreliable value formula to process the battery measured data to obtain the measured unreliable value corresponding to the battery measured data; and using the unreliable value formula to process the SOC to-be-updated correction data to obtain the to-be-updated unreliable value corresponding to the SOC to-be-updated correction data, the unreliable value formula is Q(CTBm)=ABS(Io-CTBm)*f+Do*g+(C T -Co)*h, Q(CTBm) is the unreliable value corresponding to the preset current CTBm, is the measured unreliable value or the unreliable value to be updated; ABS is the absolute value function; Io is the current used to calculate the unreliable value, is the measured current I T Or preset current In; f is the current coefficient; Do is the cumulative current error used to calculate the unreliable value, which can be the measured cumulative current error D T , or it can be the preset cumulative current error Dn; g is the cumulative current error coefficient; Co is the cumulative historical power used to calculate the unreliable value, which can be the measured cumulative historical power C T, can also be a preset cumulative historical power Cn; h is the cumulative historical power coefficient. It can be understood that f, g and h can be determined by the user based on experience.

[0145] In one embodiment, step S232, i.e., processing the battery measured data and the SOC to-be-updated correction data to obtain the measured unreliable value corresponding to the battery measured data and the to-be-updated unreliable value corresponding to the SOC to-be-updated correction data, includes:

[0146] S2321: Use the measured unreliable value formula Q T (CTBm) = ABS (I T -CTBm)*f+D T *g+(C T -C T )*h is used to calculate the actual measured data of the battery and obtain the actual measured unreliable value corresponding to the actual measured data of the battery.

[0147] S2322: Use the formula of unreliable value to be updated Qn(CTBm)=ABS(In-CTBm)*f+Dn*g+(C T -Cn)*h calculates the SOC to-be-updated correction data and the battery measured data to obtain the to-be-updated unreliable value corresponding to the SOC to-be-updated correction data.

[0148] Among them, Q T (CTBm) is the measured unreliable value corresponding to the measured battery data; CTBm is the preset current; ABS is the absolute value function; I T , D T and C T They are respectively the measured current, measured cumulative current error and measured cumulative historical power in the measured battery data; Qn(CTBm) is the unreliable value to be updated corresponding to the SOC correction data to be updated; In, Dn and Cn are respectively the preset current, preset cumulative current error and preset cumulative historical power corresponding to the SOC correction data to be updated; f is the current coefficient; g is the cumulative current error coefficient; h is the cumulative historical power coefficient.

[0149] The following example illustrates the process of updating configuration revision data:

[0150] Assume that the preset SOC is 75%, the preset currents CTB1=0.2, CTB2=0.7, CTB3=1.2, CTB4=1.7 and CTB5=2.2, f=1000, g=10, h=0.01, which are for example only and are not accurate coefficients for actual use. The coefficients can be adjusted according to the battery and project conditions. In the initial state, the 5 configuration correction data are obtained as follows:

[0151] CTB1=0.2C: empty;

[0152] CTB2 = 0.7C: Empty;

[0153] CTB3 = 1.2C: Empty;

[0154] CTB4 = 1.7C: Empty;

[0155] CTB5 = 2.2C: Empty;

[0156] When the measured SOC reaches 75 and the measured cumulative current error is not greater than the current error tolerance value (such as 2%), obtain the first set of measured battery data [75%, 1.0C, 3.356, 3AH, 28000AH]. Since CTB2 < 1.0C < CTB3, the configuration correction data corresponding to CTB2 and CTB3 are the SOC data to be updated and corrected. Among them, the configuration correction data corresponding to CTB2 is the first data to be updated and corrected, and the configuration correction data corresponding to CTB3 is the second data to be updated and corrected. Since these two SOC data to be updated and corrected are empty in the initial state (1), the measured battery data can be directly used to update the SOC data to be updated and corrected, and the following 5 sets of configuration correction data are obtained:

[0157] CTB1 = 0.2C: Empty;

[0158] CTB2=0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

[0159] CTB3=1.2C: [75%, 1.0C, 3.412, 6AH, 22000AH];

[0160] CTB4 = 1.7C: Empty;

[0161] CTB5 = 2.2C: Empty;

[0162] When the measured SOC reaches 75% and the measured cumulative current error is not greater than the current error tolerance value (such as 2%), obtain the second set of measured battery data [75%, 0.3C, 3.356, 3AH, 28000AH]. Since CTB1 < 0.3C < CTB2, the configuration correction data corresponding to CTB1 and CTB2 are the SOC data to be updated and corrected. Among them, the configuration correction data corresponding to CTB1 is the first data to be updated and corrected, and the configuration correction data corresponding to CTB2 is the second data to be updated and corrected. According to the unreliable value formula, obtain the unreliable values to be updated corresponding to the SOC data to be updated and corrected and the measured unreliable values corresponding to the measured battery data as follows:

[0163] The unreliable values to be updated corresponding to the SOC data to be updated and corrected are as follows:

[0164] CTB1 = 0.2C: Empty;

[0165] Qn(CTB1) is empty;

[0166] CTB2=0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

[0167] Qn(CTB2)=(1.0–0.7)*1000+6*10+(28000–22000)*0.01=420;

[0168] The measured unreliable values ​​corresponding to the measured battery data are as follows:

[0169] CTB1=0.2C: [75%, 0.3C, 3.356, 3AH, 28000AH];

[0170] Q T (CTB1)=(0.3–0.2)*1000+3*10+(28000–28000)*0.01=130;

[0171] CTB2=0.7C: [75%, 0.3C, 3.356, 3AH, 28000AH];

[0172] Q T (CTB2)=(0.7–0.3)*1000+3*10+(28000–28000)*0.01=430;

[0173] Since Qn(CTB1) is empty, Q T (CTB1) = 130, needs to be updated; since Qn(CTB2) = 420 T (CTB2) = 430, no row update is required, then the updated 5 configuration correction data are as follows:

[0174] CTB1=0.2C: [75%, 0.3C, 3.356, 3AH, 28000AH];

[0175] CTB2=0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

[0176] CTB3=1.2C: [75%, 1.0C, 3.412, 6AH, 22000AH];

[0177] CTB4=1.7C: empty;

[0178] CTB5=2.2C: empty;

[0179] ​When the measured SOC reaches 75% and the measured cumulative current error is not greater than the current error tolerance value (such as 2%), the third set of measured battery data [75%, 1.3C, 3.458, 5AH, 30000AH] is obtained. Since CTB3 < 1.3C < CTB4, the configuration correction data corresponding to CTB3 and CTB4 are the SOC data to be updated and corrected. Among them, the configuration correction data corresponding to CTB3 is the first data to be updated and corrected, and the configuration correction data corresponding to CTB4 is the second data to be updated and corrected. According to the unreliable value formula, the unreliable values to be updated corresponding to the SOC data to be updated and corrected and the measured unreliable values corresponding to the measured battery data are obtained as follows:

[0180] The unreliable values to be updated corresponding to the SOC data to be updated and corrected are as follows:

[0181] CTB3 = 1.2C: [75%, 1.0C, 3.412, 6AH, 22000AH];

[0182] Qn(CTB3) = (1.2 - 1.0) * 1000 + 6 * 10 + (30000 - 22000) * 0.01 = 340;

[0183] CTB4 = 1.7C: empty

[0184] Qn(CTB4) is empty;

[0185] The measured unreliable values corresponding to the measured battery data are as follows:

[0186] CTB3 = 1.2C: [75%, 1.3C, 3.458, 5AH, 30000AH];

[0187] Q T (CTB3) = (1.3 - 1.2) * 1000 + 5 * 10 + (30000 - 30000) * 0.01 = 150;

[0188] CTB4 = 1.7C: [75%, 1.3C, 3.458, 5AH, 30000AH];

[0189] Q T (CTB4) = (1.7 - 1.3) * 1000 + 5 * 10 + (30000 - 30000) * 0.01 = 450;

[0190] Since Qn(CTB3) = 340 > Q T (CTB3) = 150, an update is required; since Qn(CTB4) is empty and Q T (CTB4) = 450, an update is required. The five configuration correction data to be updated are as follows:

[0191] CTB1 = 0.2C: [75%, 0.3C, 3.356, 3AH, 28000AH];

[0192] CTB2 = 0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

[0193] CTB3=1.2C: [75%, 1.3C, 3.458, 5AH, 30000AH];

[0194] CTB4=1.7C: [75%, 1.3C, 3.458, 5AH, 30000AH];

[0195] CTB5 = 2.2C: empty;

[0196] When the measured SOC reaches 75% and the measured cumulative current error is not greater than the current error tolerance value (such as 2%), obtain the measured data of the 4th battery [75%, 1.9C, 3.485, 4AH, 35000AH]. Since CTB4 < 1.9C < CTB5, the configuration correction data corresponding to CTB4 and CTB5 are the SOC to-be-updated correction data. Among them, the configuration correction data corresponding to CTB4 is the first to-be-updated correction data, and the configuration correction data corresponding to CTB5 is the second to-be-updated correction data. According to the unreliable value formula, obtain the to-be-updated unreliable value corresponding to the SOC to-be-updated correction data and the measured unreliable value corresponding to the battery measured data as follows:

[0197] The to-be-updated unreliable value corresponding to the SOC to-be-updated correction data is as follows:

[0198] CTB4 = 1.7C: [75%, 1.3C, 3.458, 5AH, 30000AH];

[0199] Qn(CTB4) = (1.7 – 1.3) * 1000 + 5 * 10 + (30000 – 22000) * 0.01 = 530;

[0200] CTB5 = 2.2C: empty;

[0201] Qn(CTB4) is empty;

[0202] The measured unreliable value corresponding to the battery measured data is as follows:

[0203] CTB4 = 1.7C: [75%, 1.9C, 3.485, 4AH, 35000AH];

[0204] Q T (CTB4) = (1.9 – 1.7) * 1000 + 4 * 10 + (35000 – 35000) * 0.01 = 240

[0205] CTB5=2.2C: [75%, 1.9C, 3.485, 4AH, 35000AH];

[0206] Q T (CTB5)=(2.2–1.9)*1000+4*10+(35000–35000)*0.01=340

[0207] Since Qn(CTB4)=530>Q T (CTB4) = 240, needs to be updated; since Qn(CTB5) is empty, Q T (CTB5) = 340, needs to be updated, then the updated 5 configuration correction data are as follows:

[0208] CTB1=0.2C: [75%, 0.3C, 3.356, 3AH, 28000AH];

[0209] CTB2=0.7C: [75%, 1.0C, 3.412, 6AH, 22000AH];

[0210] CTB3=1.2C: [75%, 1.3C, 3.458, 5AH, 30000AH];

[0211] CTB4=1.7C: [75%, 1.9C, 3.485, 4AH, 35000AH];

[0212] CTB5=2.2C: [75%, 1.9C, 3.485, 4AH, 35000AH];

[0213] Similarly, when the measured SOC reaches the preset SOC and the measured cumulative current error is not greater than the current error tolerance value, the BMS can use the measured current, the measured cumulative current error and the measured cumulative historical power in the battery measured data to calculate the measured unreliable value corresponding to the battery measured data; and use the SOC to-be-updated correction data having the same preset SOC as the measured SOC to be updated to calculate its corresponding unreliable value to be updated, that is, use the preset cumulative current error and the preset cumulative historical power in the SOC to-be-updated correction data to obtain the unreliable value to be updated corresponding to the SOC to-be-updated correction data, and use the battery measured data corresponding to the measured unreliable value less than the unreliable value to be updated to update the SOC to-be-updated correction data, so as to realize real-time updating of the configuration correction data in the correction data table, ensure the reliability of subsequent SOC estimation, and avoid the situation where the configuration correction data pre-stored in the correction data table cannot accurately correct the measured SOC when the physical condition of the battery changes.

[0214] For example, during the first execution of steps S11-S14, during the processing of the measured battery data corresponding to the measured current of 1.2C, the two configuration correction data [75%, 1.0C, A, B, C] and [75%, 1.3C, E, F, G] pre-stored in the correction data table are used to determine the SOC upper limit correction data and the SOC lower limit correction data, respectively, so as to determine the final target SOC. After [75%, 1.0C, A, B, C] is updated to [75%, 0.9C, A', B', C'], the subsequent execution of steps S11-S14 again requires that the two configuration correction data [75%, 0.9C, A', B', C'] and [75%, 1.3C, E, F, G] be used as the SOC upper limit correction data and the SOC lower limit correction data, respectively, so as to determine the final target SOC.

[0215] In one embodiment, before executing step S11, it is necessary to predetermine a correction data table, specifically, it is necessary to determine the preset SOC and preset current in the correction data table through experiments, so that the measured voltage, measured cumulative current error and measured cumulative historical power corresponding to the preset SOC and preset current can be updated in real time according to the actual operating conditions of the battery.

[0216] In one embodiment, a battery management system is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the battery SOC estimation method in the above embodiment is implemented, for example Figure 1 S11-S14 as shown, or Figure 2 As shown in S21-S23, to avoid repetition, they are not repeated here.

[0217] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the battery SOC estimation method in the above embodiment is implemented, for example Figure 1 S11-S14 as shown, or Figure 2 As shown in S21-S23, to avoid repetition, they are not repeated here.

[0218] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0219] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0220] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0221] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0222] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A battery SOC estimation method, characterized in that: include: Obtaining battery measured data, wherein the battery measured data includes measured current, measured voltage, measured SOC and measured accumulated historical power; According to the measured current and the measured voltage, a correction data table is searched to obtain SOC upper limit correction data and SOC lower limit correction data matching the measured current and the measured voltage; Determining an SOC upper limit threshold and an SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data; The measured SOC is corrected by using the SOC upper limit threshold and the SOC lower limit threshold to obtain a target SOC; The querying of the correction data table according to the measured current and the measured voltage to obtain the SOC upper limit correction data and the SOC lower limit correction data matching the measured current and the measured voltage includes: If the preset current in the correction data table is equal to the measured current, the first correction data corresponding to the preset current is used as the SOC correction data to be selected; if the preset current in the correction data table is not equal to the measured current, the second correction data and the third correction data in the correction data table are obtained, and the measured current, the second correction data and the third correction data are processed by a data estimation formula to obtain the SOC correction data to be selected; the data estimation formula is ST=(Sa-Sb)*(IT-Ib) / (Ia-Ib)+Sb; if Sa is the preset voltage in the second correction data, Sb is the preset voltage in the third correction data, then ST is the preset voltage in the SOC correction data to be selected; if Sa is the preset SOC in the second correction data, Sb is the preset SOC in the third correction data, then ST is the preset SOC in the SOC correction data to be selected; if Sa is the preset accumulated historical power in the second correction data, Sb is the preset accumulated historical power in the third correction data, then ST is the preset accumulated historical power in the SOC correction data to be selected; I T is the measured current; Ia is the preset current in the second correction data; Ib is the preset current in the third correction data, wherein the preset current in the second correction data is smaller than the measured current, and the preset current in the third correction data is larger than the measured current; If the preset voltage in the SOC to-be-selected correction data is greater than the measured voltage, the difference between the preset voltage and the measured voltage in the SOC to-be-selected correction data is determined as a first difference, and the SOC to-be-selected correction data with the smallest first difference is determined as the SOC upper limit correction data; if the preset voltage in the SOC to-be-selected correction data is less than the measured voltage, the difference between the measured voltage and the preset voltage in the SOC to-be-selected correction data is determined as a second difference, and the SOC to-be-selected correction data with the smallest second difference is determined as the SOC lower limit correction data; The SOC correction data to be selected include: preset current, preset voltage, preset SOC and preset accumulated historical power.

2. The battery SOC estimation method according to claim 1, characterized in that: The determining of the SOC upper limit threshold and the SOC lower limit threshold according to the measured accumulated historical power, the SOC upper limit correction data and the SOC lower limit correction data includes: According to the measured cumulative historical power and the preset cumulative current error and the preset cumulative historical power in the SOC upper limit correction data, an upper limit error value is obtained, and a sum of the preset SOC in the SOC upper limit correction data and the upper limit error value is determined as the SOC upper limit threshold; A lower limit error value is obtained based on the measured cumulative historical power and the preset cumulative current error and the preset cumulative historical power in the SOC lower limit correction data, and the difference between the preset SOC in the SOC lower limit correction data and the lower limit error value is determined as the SOC lower limit threshold.

3. The battery SOC estimation method according to claim 1, characterized in that: The step of correcting the measured SOC by using the SOC upper limit threshold and the SOC lower limit threshold to obtain a target SOC includes: If the measured SOC is greater than the SOC upper limit threshold, determining the preset SOC in the SOC upper limit correction data as the target SOC; If the measured SOC is less than the SOC lower limit threshold, determining the preset SOC in the SOC lower limit correction data as the target SOC; If the measured SOC is not less than the SOC lower limit threshold and the measured SOC is not greater than the SOC upper limit threshold, the measured SOC is determined as the target SOC.

4. The battery SOC estimation method according to claim 1, characterized in that: The battery measured data also includes measured cumulative current error; After obtaining the measured battery data, the battery SOC estimation method further includes: comparing the measured cumulative current error with the current error tolerance value; If the measured cumulative current error is greater than the current error tolerance value, querying the correction data table according to the measured current and the measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data that match the measured current and the measured voltage; If the measured cumulative current error is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the battery measured data.

5. The battery SOC estimation method according to claim 4, characterized in that: The configuration correction data includes a preset current, a preset voltage, a preset SOC, a preset accumulated current error and a preset accumulated historical power; The updating of the configuration correction data in the correction data table based on the battery measured data includes: Acquire all the SOC preliminary correction data in the correction data table that match the preset SOC and the measured SOC, determine the SOC preliminary correction data that is adjacent to the preset current and the measured current as the first correction data to be updated and the second correction data to be updated, determine the first correction data to be updated and the second correction data to be updated as the SOC correction data to be updated, the preset current in the first correction data to be updated is less than the measured current, and the preset current in the second correction data to be updated is greater than the measured current; Processing the battery measured data and the SOC corrected data to be updated to obtain a measured unreliable value corresponding to the battery measured data and a to-be-updated unreliable value corresponding to the SOC corrected data to be updated; If the unreliable value to be updated is empty, or the actually measured unreliable value is smaller than the unreliable value to be updated, the SOC correction data to be updated is updated using the actually measured battery data.

6. The battery SOC estimation method according to claim 5, characterized in that: The processing of the battery measured data and the SOC to-be-updated correction data to obtain the measured unreliable value corresponding to the battery measured data and the to-be-updated unreliable value corresponding to the SOC to-be-updated correction data includes: Using the measured unreliable value formula Q T (CTBm) = ABS (I T -CTBm)*f+D T *g+(C T -C T )*h calculates the battery measured data to obtain a measured unreliable value corresponding to the battery measured data; The formula of unreliable value to be updated is adopted: Qn(CTBm)=ABS(In-CTBm)*f+Dn*g+(C T -Cn)*h calculates the SOC to-be-updated correction data and the battery measured data to obtain an unreliable value to be updated corresponding to the SOC to-be-updated correction data; Among them, Q T (CTBm) is the measured unreliable value corresponding to the measured data of the battery; CTBm is the preset current; ABS is the absolute value function; I T , D T and C T They are respectively the measured current, measured cumulative current error and measured cumulative historical power in the measured battery data; Qn(CTBm) is the unreliable value to be updated corresponding to the SOC correction data to be updated; In, Dn and Cn are respectively the preset current, preset cumulative current error and preset cumulative historical power corresponding to the SOC correction data to be updated; f is the current coefficient; g is the cumulative current error coefficient; h is the cumulative historical power coefficient.

7. A battery management system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the battery SOC estimation method according to any one of claims 1 to 6 is implemented.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the battery SOC estimation method according to any one of claims 1 to 6 is implemented.

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