CN114487865B

CN114487865B - Battery SOC estimation method, battery management system and computer readable storage medium

Info

Publication number: CN114487865B
Application number: CN202011172369.2A
Authority: CN
Inventors: 尹韶文; 林培锦; 尹雪芹
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2020-10-28
Filing date: 2020-10-28
Publication date: 2025-01-14
Anticipated expiration: 2040-10-28
Also published as: CN114487865A

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

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

Technical Field

The present invention relates to the field of battery management technologies, and in particular, to a battery SOC estimation method, a battery management system, and a computer readable storage medium.

Background

SOC (State Of Charge), which is the short term Of battery State Of Charge or remaining Charge, refers to the ratio Of the remaining dischargeable Charge after a battery is used for a period Of time or is left unused for a long period Of time to the Charge Of its fully charged State. SOC is an important parameter of the whole battery energy storage system, and accurate estimation of SOC can realize reasonable utilization of battery energy, prevent unreasonable use problems such as battery overcharge or overdischarge and the like, so as to prolong the service life of the battery.

Existing SOC estimation methods include, but are not limited to, ampere-hour integration, real-time voltage correction, open-circuit voltage, and neural network methods, each of which has respective advantages and disadvantages. The ampere-hour integration method realizes SOC estimation according to current accumulation, has simple operation and low resource requirement, but depends on the accuracy of sampling current, has large requirement on calibrating high voltage during filling and low voltage during emptying, and has lower accuracy. The real-time voltage correction method is to estimate the SOC according to the real-time voltage, the real-time current and the known charge-discharge voltage curves of each current, and can accurately estimate the SOC when the voltage change is obvious or the battery use frequency is high, and the error is small, but the accuracy of the SOC estimation is low and the error is large when the voltage change is not obvious or the battery use frequency is low. The open-circuit voltage method is to measure after the battery is kept stand for several hours without charging and discharging, and the open-circuit voltage curve is utilized to estimate the SOC, so that the current interference can be avoided by keeping the battery stand, the accuracy of SOC estimation is ensured, but the real-time performance is poor. The neural network method is to correct and accumulate the battery data acquired under different operating conditions by using the neural network to perform SOC estimation, and has the advantages of higher accuracy, higher resource requirement and higher operating condition operation data requirement.

Disclosure of Invention

The embodiment of the invention provides a battery SOC estimation method, a battery management system and a computer readable storage medium, which are used for solving the problems that the existing SOC estimation method cannot be high in accuracy, low in operation resources and high in instantaneity.

The embodiment of the invention provides a battery SOC estimation method, which comprises the following steps:

Obtaining measured data of a battery, wherein the measured data of the battery comprise measured current, measured voltage, measured SOC and measured accumulated historical electric quantity;

Inquiring a correction data table according to the actual measured current and the actual measured voltage, and acquiring SOC upper limit correction data and SOC lower limit correction data matched with the actual measured current and the actual measured voltage;

determining an upper SOC limit threshold value and a lower SOC limit threshold value according to the actually measured accumulated historical electric quantity, the upper SOC limit correction data and the lower SOC limit correction data;

and correcting the actually measured SOC by adopting the SOC upper limit threshold and the SOC lower limit threshold to obtain a target SOC.

Preferably, the step of inquiring a correction data table according to the measured current and the measured voltage to obtain upper limit SOC correction data and lower limit SOC correction data matched with the measured current and the measured voltage includes:

Inquiring a correction data table based on the measured current, and acquiring SOC to-be-selected correction data of which the preset current is matched with the measured current in the correction data table;

acquiring the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC to-be-selected correction data;

the SOC data to be modified comprises preset current, preset voltage, preset SOC and preset accumulated historical electric quantity.

Preferably, the step of querying a correction data table based on the measured current, and obtaining SOC candidate correction data in which a preset current in the correction data table matches with the measured current includes:

if the preset current in the correction data table is equal to the actual measured current, taking first correction data corresponding to the preset current as SOC to-be-selected correction data;

If the preset current in the correction data table is not equal to the actual measurement current, second correction data and third correction data in the correction data table are obtained, and SOC to-be-selected correction data are obtained based on the actual measurement current, the second correction data and the third correction data, wherein the preset current in the second correction data is smaller than the actual measurement current, and the preset current in the third correction data is larger than the actual measurement current.

Preferably, the obtaining SOC candidate correction data based on the measured current, the second correction data, and the third correction data includes:

Processing the actually measured current, the second correction data and the third correction data by adopting a data estimation formula to obtain the data to be corrected of the SOC;

The data estimation formula is ST= (Sa-Sb)/(Ia-Ib) +Sb, if Sa is preset voltage in the second correction data, sb is preset voltage in third correction data, ST is preset voltage in the SOC to-be-corrected data, if Sa is preset SOC in the second correction data, sb is preset SOC in the third correction data, ST is preset SOC in the SOC to-be-corrected data, if Sa is preset accumulated historical electric quantity in the second correction data, sb is preset accumulated historical electric quantity in the third correction data, ST is preset accumulated historical electric quantity in the SOC to-be-corrected data, IT is actual measurement current, ia is preset current in the second correction data, and Ib is preset current in the third correction data.

Preferably, the obtaining the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC candidate correction data includes:

If the preset voltage in the SOC to-be-selected correction data is larger than the actual measurement voltage, determining a difference value between the preset voltage and the actual measurement voltage in the SOC to-be-selected correction data as a first difference value, and determining the SOC to-be-selected correction data with the minimum first difference value as SOC upper limit correction data;

if the preset voltage in the SOC to-be-corrected data is smaller than the actual measurement voltage, determining a difference value between the actual measurement voltage and the preset voltage in the SOC to-be-corrected data as a second difference value, and determining the SOC to-be-corrected data with the minimum second difference value as SOC lower limit correction data.

Preferably, the determining the SOC upper limit threshold value and the SOC lower limit threshold value according to the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data includes:

Acquiring an upper limit error value according to the actually measured accumulated historical electric quantity and a preset accumulated current error and a preset accumulated historical electric quantity in the SOC upper limit correction data, and determining the sum of the preset SOC in the SOC upper limit correction data and the upper limit error value as an SOC upper limit threshold;

and acquiring a lower limit error value according to the actually measured accumulated historical electric quantity and a preset accumulated current error and a preset accumulated historical electric quantity in the SOC lower limit correction data, and determining a difference value between a preset SOC in the SOC lower limit correction data and the lower limit error value as a SOC lower limit threshold.

Preferably, the 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 larger than the SOC upper limit threshold, determining a preset SOC in the SOC upper limit correction data as the target SOC;

If the measured SOC is smaller than the SOC lower limit threshold, determining a preset SOC in the SOC lower limit correction data as the target SOC;

and 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, determining the measured SOC as the target SOC.

Preferably, the battery measured data further includes a measured accumulated current error;

after the obtaining of the battery measured data, the battery SOC estimation method further includes:

Comparing the actually measured accumulated current error with a current error tolerance value;

If the actually measured accumulated current error is larger than the current error tolerance value, executing the inquiry correction data table according to the actually measured current and the actually measured voltage to obtain SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage;

And if the actually measured accumulated current error is not larger than the current error tolerance value, updating configuration correction data in the correction data table based on the actually measured battery data.

Preferably, the updating the configuration correction data in the correction data table based on the battery measured data includes:

Acquiring initial SOC correction data of all the preset SOCs and the actually measured SOCs matched in the correction data table, determining the initial SOC correction data with the preset current adjacent to the actually measured current as first correction data to be updated and second correction data to be updated, determining the first correction data to be updated and the second correction data to be updated as SOC correction data to be updated, wherein the preset current in the first correction data to be updated is smaller than the actually measured current, and the preset current in the second correction data to be updated is larger than the actually measured current;

Processing the battery actual measurement data and the SOC to-be-updated correction data to obtain an actual measurement unreliable value corresponding to the battery actual measurement data and a to-be-updated unreliable value corresponding to the SOC to-be-updated correction data;

and if the unreliable value to be updated is empty or the actually measured unreliable value is smaller than the unreliable value to be updated, updating the correction data to be updated of the SOC by adopting the actually measured data of the battery.

Preferably, the processing the actually measured data of the battery and the to-be-updated correction data of the SOC to obtain an actually measured unreliable value corresponding to the actually measured data of the battery and a to-be-updated unreliable value corresponding to the to-be-updated correction data of the SOC includes:

Calculating the measured data of the battery by adopting a measured unreliable value formula QT (CTBm) =ABS (IT-CTBm) ×f+DT+g+ (CT-CT) h, and obtaining a measured unreliable value corresponding to the measured data of the battery;

Calculating the to-be-updated correction data of the SOC and the actually measured data of the battery by adopting an unreliable value formula Qn (CTBm) =ABS (In-CTBm) ×f+Dn×g+ (CT-Cn) ×h to obtain an unreliable value to be updated corresponding to the to-be-updated correction data of the SOC;

Wherein QT (CTBm) is an actual measurement unreliable value corresponding to actual measurement data of the battery, CTBm is preset current, ABS is an absolute function, IT, DT and CT are respectively measured current, actual measurement accumulated current error and actual measurement accumulated historical electric quantity In the actual measurement data of the battery, qn (CTBm) is an unreliable value to be updated corresponding to correction data to be updated of the SOC, in, dn and Cn are respectively preset current, preset accumulated current error and preset accumulated historical electric quantity corresponding to correction data to be updated of the SOC, f is a current coefficient, g is an accumulated current error coefficient, and h is an accumulated historical electric quantity coefficient.

The embodiment of the invention also provides a battery management system, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor realizes the battery SOC estimation method when executing the computer program.

Embodiments of the present invention also provide a computer-readable storage medium storing a computer program which, when executed by a processor, implements the battery SOC estimation method as described above.

According to the battery SOC estimation method, the battery management system and the computer readable storage medium, the correction data table is inquired according to the actual measured current and the actual measured voltage, the SOC upper limit correction data and the SOC lower limit correction data are quickly determined, so that the SOC estimation requires low resources and is helpful for providing the instantaneity of the SOC estimation, the SOC upper limit threshold and the SOC lower limit threshold are determined based on the actual measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data, the actual measured SOC is corrected by utilizing the SOC upper limit threshold and the SOC lower limit threshold, the output target SOC is high in accuracy, and the error with the actual battery SOC is small, so that the SOC estimation can meet the requirements of high accuracy, low resource requirements and high instantaneity.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments of the present invention will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flowchart of a battery SOC estimation method according to an embodiment of the present invention;

fig. 2 is another flowchart of a battery SOC estimation method in an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The BATTERY SOC estimation method provided by the embodiment of the invention can be applied to a BATTERY management system (BMS MANAGEMENT SYSTEM), and the BMS is connected with a BATTERY and is used for estimating the SOC of the BATTERY so that the estimated target SOC has the advantages of high accuracy, low resource requirement, high instantaneity and the like.

In this embodiment, the memory of the BMS stores a correction data table in advance, and the correction data table is a data table in which correction data of different configurations is recorded in advance. The configuration correction data refers to data formed according to the battery operation condition before the system time of acquiring the battery actual measurement data and recorded in the memory of the BMS, and can be understood as data required to be called for realizing estimation correction of the actual measurement SOC.

Because the storage resources in the BMS are limited, the configuration correction data in the correction data table are limited, and x×y configuration correction data can be stored in the correction data table according to the storage resources provided by the BMS, where X is the number of preset SOCs, for example, if the preset SOCs have values of 5%, 15%, 25%, 75%, 85% and 95%, X is 6, Y is the number of preset currents, and if the preset currents have values of 0.2C, 0.5C, 0.9C, 1C and 2.2C, Y is 5, 30 configuration correction data are stored in the correction data table.

As an example, according to test data formed in the test operation process of the battery in advance, voltage-current actual measurement curves corresponding to the X preset SOCs are drawn, and then Y preset currents are determined according to the current sampling rule, so as to determine preset voltages according to the preset currents and the voltage-current actual measurement curves. In this example, Y preset currents may be determined by an arithmetic rule to minimize the difference, so as to help reduce the error of the subsequent SOC estimation, where the Y preset currents are preset currents CTBm, where 1+.m+.y, and as shown above, the preset currents ctb1=0.2, ctb2=0.7, ctb3=1.2, ctb4=1.7, ctb5=2.2.

In this example, the configuration correction data includes a preset current, a preset voltage, a preset SOC, a preset accumulated current error, and a preset accumulated historical electric quantity, and [ SOCn, in, vn, dn, cn ] may be used to represent the nth configuration correction data, where 1+.n+.x.y. The preset SOC is a preconfigured SOC of the battery that may need correction, and may be represented by SOCn. The preset current refers to a pre-configured current of a battery working process which may need to be corrected, and may be represented by In, and specifically may be a charging current or a discharging current. The preset voltage is the voltage required for implementing the SOC estimation correction, which is formed and recorded before the system time of receiving the measured data of the battery, and can be expressed by Vn. The preset accumulated current error refers to the accumulation of all error currents before the system time of receiving the measured data of the battery, and can be expressed by Dn. The preset accumulated historical electric quantity refers to the accumulation of all electric quantities before the system time of receiving the measured data of the battery, and can be represented by Cn. For example, when the SOC estimation is performed by using the real-time voltage correction method, the preset SOC, the preset current, and the preset voltage are known specific sampling points in each current charge-discharge voltage curve.

In one embodiment, as shown in fig. 1, a battery SOC estimation method is provided, which is described by taking a BMS as an example, and includes the following steps:

and S11, acquiring measured data of the battery, wherein the measured data of the battery comprise measured current, measured voltage, measured SOC and measured accumulated historical electric quantity.

The battery measured data refer to data related to the battery, which are acquired by the BMS in real time. The actually measured current is the current obtained by the BMS in the working process of the battery, and can be expressed by I _T, and can be understood as the current determined when the battery is processed by adopting an SOC algorithm method, and can be specifically the charging current or the discharging current. The measured voltage is the voltage obtained by the BMS in real time in the working process of the battery, can be expressed by V _T, and can be understood as the voltage determined when the battery is processed by adopting an SOC algorithm method. The measured SOC is the SOC of the battery acquired by the BMS in real time, and may be represented by SOC _T, which may be understood as an estimated SOC determined by an SOC estimation method. The actual measurement history electric quantity is the accumulation of all electric quantities after receiving the actual measurement data of the battery, and can be represented by C _T. For example, the actual measured accumulated electric quantity is the accumulation of all the charged electric quantity in the battery charging process, and the actual measured accumulated electric quantity is the accumulation of all the discharged electric quantity in the battery discharging process. It can be appreciated that the measured accumulated historical electricity quantity includes the accumulated historical electricity quantity before the system time and the electricity quantity in the measured data of the current battery.

As an example, the BMS acquires battery actual measurement data in real time, where the battery actual measurement data includes actual measurement current, actual measurement voltage, actual measurement SOC, actual measurement accumulated current error, and actual measurement accumulated historical electric quantity, and the battery actual measurement data may be represented by [ SOC _T、I_T、V_T、D_T、C_T ]. For example, during the charging process of the battery, when the measured current of 1.2C is used to charge the measured voltage V0, the SOC of the measured current of 1.2C and the measured voltage V0 may be estimated by using a real-time voltage correction method to obtain the measured SOC0, and the measured accumulated current error D0 and the measured accumulated historical electric quantity C0 are calculated by combining configuration correction data to obtain the measured data [ SOC0,1.2C, V0, D0, C0].

And S12, inquiring a correction data table according to the measured current and the measured voltage, and acquiring SOC upper limit correction data and SOC lower limit correction data matched with the measured current and the measured voltage.

When the real-time voltage correction method is adopted for SOC estimation, the accuracy of SOC estimation is higher when the SOC is in the middle section (such as 30% -70%), the error between the estimated actual SOC and the actual SOC of the battery is smaller, and the accuracy of SOC estimation is lower when the SOC is in the low section (such as 0% -30%) or the high section (such as 70% -100%), the error between the estimated actual SOC and the actual SOC of the battery is larger, and correction is needed, so that correction data of the upper limit and the lower limit of the SOC matched with the actual current and the actual voltage are needed to be obtained according to the actual current and the actual voltage, and correction is conducted by utilizing the correction data of the upper limit and the correction data of the lower limit of the SOC.

The correction data table is a data table in which correction data of different configurations is recorded in advance. The configuration correction data refers to data formed according to the battery operation condition before the system time of acquiring the battery actual measurement data and recorded in the memory of the BMS, and can be understood as data required to be called for realizing estimation correction of the actual measurement SOC. Generally, the configuration correction data can be understood that under the condition that the preset current and the preset voltage are met, the corresponding actually measured SOC should be within the error range of the preset SOC so as to correct the actually measured SOC, so that the error between the target SOC determined after correction and the actual SOC of the battery is ensured to be smaller, and the accuracy of the target SOC is improved. For example, when the preset current is 1.2C, the configuration correction data of the preset current of 1.2C stored in the correction data table is as follows:

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

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

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

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

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

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

the SOC upper limit correction data is configuration correction data for correcting an upper limit of the actual SOC. The SOC lower limit correction data is configuration correction data for correcting the lower limit of the actually measured SOC.

As an example, after the BMS receives the battery measured data, it is required to query a prestored correction data table based on the measured current and the measured voltage, select configuration correction data in which the preset current is matched with the measured current, and the preset voltage is matched with the measured voltage, and determine the configuration correction data as SOC upper limit correction data and SOC lower limit correction data. In this example, the BMS may select configuration correction data having a preset voltage closest to the actual measurement voltage from all configuration correction data having a preset current matched to the actual measurement current and a preset voltage greater than the actual measurement voltage to determine the configuration correction data as SOC upper limit correction data, and select configuration correction data having a preset voltage closest to the actual measurement voltage from all configuration correction data having a preset current matched to the actual measurement current and a preset voltage less than the actual measurement voltage to determine the configuration correction data as SOC lower limit correction data.

And S13, determining an upper limit SOC threshold value and a lower limit SOC threshold value according to the actually measured and accumulated historical electric quantity, the upper limit SOC correction data and the lower limit SOC correction data.

The SOC upper limit threshold is an evaluation threshold for comparing and judging whether or not correction of the upper limit of the measured SOC is necessary. The SOC lower limit threshold value is an evaluation threshold value for comparing and judging whether or not correction of the lower limit of the measured SOC is necessary.

As an example, the BMS executes threshold determination logic to process the upper SOC limit correction data to obtain an upper SOC limit threshold and to process the lower SOC limit correction data to obtain a lower SOC limit threshold. Understandably, the BMS can execute the threshold value determining logic in real time to process the actually measured accumulated electric quantity and the preset SOC, the preset accumulated electric current error and the preset accumulated electric quantity in the SOC upper limit correction data to determine the SOC upper limit threshold value, and execute the threshold value determining logic in real time to process the actually measured accumulated electric quantity and the preset SOC, the preset accumulated electric current error and the preset accumulated electric quantity in the SOC lower limit correction data to determine the SOC lower limit threshold value. In this example, the threshold determining logic refers to logic that uses the actually measured accumulated historical electric quantity, the preset SOC, the preset accumulated current error, and the preset accumulated historical electric quantity as input parameters, and processes the input parameters by using a pre-configured operation rule.

And S14, correcting the actually measured SOC by adopting an SOC upper limit threshold value and an SOC lower limit threshold value to obtain a target SOC.

The target SOC is determined after correction processing is carried out on the actually measured SOC by utilizing an SOC upper limit threshold value and an SOC lower limit threshold value, and is the finally determined SOC, so that the error between the target SOC and the actual SOC of the battery is minimum, and the accuracy is highest.

As an example, after determining the SOC upper limit threshold value and the SOC lower limit threshold value, the BMS may compare the measured SOC with the SOC upper limit threshold value and the SOC lower limit threshold value using a pre-configured SOC correction logic to determine whether correction of the measured SOC is required according to the comparison result of the measured SOC with the SOC lower limit threshold value and the SOC upper limit threshold value, and in case that correction of the measured SOC is determined to be required, how to implement correction of the measured SOC in particular. For example, when the actually 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 actually measured SOC smaller than the SOC lower limit threshold or larger than the SOC upper limit threshold, so that the target SOC determined after compensation is closer to the range between 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 minimum and the accuracy is highest. The SOC compensation rule is a preset rule for compensating the actually measured SOC, and different compensation conditions and compensation formulas corresponding to each compensation condition can be configured in the SOC compensation rule so as to determine the corresponding compensation condition according to the actual situation, so that the corresponding compensation formulas are adopted for processing.

According to the battery SOC estimation method, the correction data table is inquired according to the measured current and the measured voltage, the SOC upper limit correction data and the SOC lower limit correction data are quickly determined, so that the SOC estimation requires low resources and is beneficial to providing the real-time performance of the SOC estimation, the SOC upper limit threshold value and the SOC lower limit threshold value are determined based on the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data, the actually measured SOC is corrected by utilizing the SOC upper limit threshold value and the SOC lower limit threshold value evaluation, the output target SOC is high in accuracy, the error with the actual SOC of the battery is small, and the requirements of high accuracy, low resource requirements and high real-time performance can be met by the SOC estimation.

In one embodiment, step S12, namely, according to the measured current and the measured voltage, the correction data table is queried to obtain the SOC upper limit correction data and the SOC lower limit correction data matched with the measured current and the measured voltage, including:

S121, inquiring a correction data table based on the measured current, and acquiring SOC to-be-selected correction data with preset current matched with the measured current in the correction data table.

S122, acquiring the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC candidate correction data.

The SOC candidate correction data refers to configuration correction data in which a preset current matches an actual current, that is, all configuration correction data corresponding to the preset current matching the actual current are determined as SOC candidate correction data. In this example, the preset current that matches the measured current may be the preset current that is equal to the measured current, or may be the preset current that is not equal to but closest to the measured current.

As an example, if the actual measured data of the battery [ SOC0,1.2C, v0, d0, C0] is 1.2C, the configuration correction data corresponding to all the preset currents 1.2C obtained in the correction data table is determined as the SOC candidate correction data, for example, the SOC candidate correction data is as follows:

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

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

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

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

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

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

In the SOC candidate correction data, when the preset current is matched with the actually measured current, the preset voltage is in direct proportion to the preset SOC, that is, the larger the preset voltage is, the larger the preset SOC is.

Understandably, the preset voltage and the measured voltage in all the SOC to-be-corrected data with the preset current and the measured current are processed in ascending order or descending order to form a voltage sequencing sequence, the SOC to-be-corrected data corresponding to two preset voltages adjacent to the measured voltage in the voltage sequencing sequence are respectively determined to be SOC upper limit correction data and SOC lower limit correction data, so that the upper limit or the lower limit of the measured SOC is corrected by the SOC upper limit correction data and the SOC lower limit correction data, the accuracy of the finally determined target SOC is ensured, and the error between the target SOC and the actual SOC of the battery is reduced.

In one embodiment, step S121, namely, based on the measured current, queries the correction data table to obtain SOC candidate correction data matching the preset current and the measured current in the correction data table, includes:

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 to-be-selected correction data.

S1212, if the preset current in the correction data table is not equal to the actual measurement current, obtaining second correction data and third correction data in the correction data table, and obtaining SOC to-be-selected correction data based on the actual measurement current, the second correction data and the third correction data, wherein the preset current in the second correction data is smaller than the actual measurement current, and the preset current in the third correction data is larger than the actual measurement current.

As an example, the measured current may be compared with the preset current in all configuration correction data in the correction data table. If the preset current is equal to the actual measured current, the configuration correction data of which the preset current is equal to the actual measured current is determined to be first correction data, and the first correction data is SOC to be corrected data. And if the preset current is not equal to the actual measured current, sequencing the actual measured current and the preset current in all the configuration correction data to obtain a current sequencing sequence, and respectively determining two configuration correction data adjacent to the actual measured current as second correction data and third correction data. For example, configuration correction data of which the preset current is smaller than the actual measured current in two preset currents adjacent to the actual measured current in the current sequencing sequence is determined as second correction data, and configuration correction data of which the preset current is larger than the actual measured current in two preset currents adjacent to the actual measured current in the current sequencing sequence is determined as third correction data.

In one embodiment, step S1212, which is based on the measured current, the second correction data, and the third correction data, obtains the SOC candidate correction data, includes processing the measured current, the second correction data, and the third correction data using a data estimation formula to obtain the SOC candidate correction data.

The data estimation formula is ST= (Sa-Sb)/(IT-Ib) +Sb, if Sa is preset voltage in the second correction data, sb is preset voltage in the third correction data, ST is preset voltage in the SOC to-be-corrected data, if Sa is preset SOC in the second correction data, sb is preset SOC in the third correction data, ST is preset SOC in the SOC to-be-corrected data, if Sa is preset accumulated historical electric quantity in the second correction data, sb is preset accumulated historical electric quantity in the third correction data, ST is preset accumulated historical electric quantity in the SOC to-be-corrected data, I _T is actual measurement current, ia is preset current in the second correction data, and Ib is preset current in the third correction data.

In this embodiment, the BMS may directly determine the actually measured current as the actually measured current, and after determining the second correction data and the third correction data, may process the actually measured current by using specific values such as the preset current, the preset voltage, the preset accumulated current error, the preset accumulated historical electric quantity, and the like in the second correction data and the third correction data, so as to determine the SOC candidate correction data.

As an example, the BMS processes the measured current and the second and third correction data by using a data estimation formula to obtain SOC to-be-selected correction data, wherein the data estimation formula is ST= (Sa-Sb)/(IT-Ib) +Sb, if Sa is a preset voltage in the second correction data, sb is a preset voltage in the third correction data, ST is a preset voltage in the SOC to-be-selected correction data, if Sa is a preset SOC in the second correction data, sb is a preset SOC in the third correction data, ST is a preset SOC in the SOC to-be-selected correction data, if Sa is a preset accumulated historical electric quantity in the second correction data, sb is a preset accumulated historical electric quantity in the third correction data, ST is a preset accumulated historical electric quantity in the SOC to-be-selected correction data, I _T is the measured current, ia is a preset current in the second correction data, and Ib is a preset current in the third correction data.

For example, when 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)

(I0-Ib)/(Ia-Ib) +vb= (3.458-3.412)/(1.2-1.0)/(1.3-1.0) +3.412= 3.443, i.e. the measured voltage V _T is 3.443, the measured cumulative current error formula is D _T = (Da-Db)/(Ia-Ib) +db= (5-6)/(1.2-1.0)/(1.3-1.0) +6=5.33, and the measured cumulative current error D _T is 5.33. The actual measurement accumulated historical electric quantity formula is C _T = (Ca-Cb)/(I0-Ib)/(Ia-Ib) +Cb= (30000-22000)/(1.2-1.0)/(1.3-1.0) +22000=27333, namely the actual measurement accumulated historical electric quantity C _T is 27333, and the finally obtained actual measurement data of the battery are [75%,1.2C,3.443,5.33AH and 27333AH ].

Further, the battery measured data further comprises an actual measured accumulated current error, correspondingly, the SOC to-be-selected correction data further comprises a preset accumulated current error, the second correction data and the third correction data also comprise the preset accumulated current error, the BMS processes the actual measured current, the second correction data and the third correction data by adopting a data estimation formula to obtain the SOC to-be-selected correction data, wherein the data estimation formula is ST= (Sa-Sb)/(IT-Ib)/(Ia-Ib) +Sb, if Sa is the preset accumulated current error in the second correction data, sb is the preset accumulated current error in the third correction data, ST is the preset accumulated current error in the SOC to-be-selected correction data, I _T is the actual measured current, ia is the preset current in the second correction data, and Ib is the preset current in the third correction data.

According to the battery SOC estimation method, the measured current, the second correction data and the third correction data can be used for quickly determining the SOC to-be-selected correction data based on the measured current, the second correction data and the third correction data, so that the obtained SOC to-be-selected correction data is used for estimating the SOC to correct, the accuracy of the finally determined target SOC is guaranteed, and errors with the actual SOC are reduced.

In one embodiment, step S122, that is, obtaining the SOC upper limit correction data and the SOC lower limit correction data based on the measured voltage and the SOC candidate correction data, includes:

S1221, if the preset voltage in the SOC candidate correction data is larger than the actual measurement voltage, determining a difference value between the preset voltage and the actual measurement voltage in the SOC candidate correction data as a first difference value, and determining the SOC candidate correction data with the minimum first difference value as the SOC upper limit correction data.

S1222, if the preset voltage in the SOC candidate correction data is smaller than the actual measurement voltage, determining the difference value between the actual measurement voltage and the preset voltage in the SOC candidate correction data as a second difference value, and determining the SOC candidate correction data with the minimum second difference value as the SOC lower limit correction data.

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

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

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

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

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

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

As an example, the measured voltage V0 is compared with preset voltages V1, V2, V3, V4, V5, and V6. If the preset voltage V5 and V6 are greater than the measured voltage V0, at this time, a difference between the preset voltage V5 and the measured voltage V0 may be calculated, and determined as a first difference V5-V0, and a difference between the preset voltage V6 and the measured voltage V0 may be calculated, and determined as a first difference V6-V0, and then the first difference V5-V0 and V6-V0 are compared, and since the first difference V5-V0 is smaller than the first difference V6-V0, the SOC to be corrected data [85%,1.2c, V5, d5, c5] corresponding to the first difference V5-V0 may be determined as the SOC upper limit correction data. If the preset voltages V1, V2, V3 and V4 are all smaller than the measured voltage V0, 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, and since V0-V4 is the smallest, the SOC candidate correction data [75%,1.2c, V4, d4, c4] corresponding to the second differences V0-V4 can be determined as the SOC lower limit correction data.

In one embodiment, step S13, that is, determining the SOC upper limit threshold value and the SOC lower limit threshold value according to the actually measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data, includes:

S131, obtaining an upper limit error value according to the actually measured accumulated historical electric quantity and the preset accumulated current error and the preset accumulated historical electric quantity in the SOC upper limit correction data, and determining the sum of the preset SOC and the upper limit error value in the SOC upper limit correction data as an SOC upper limit threshold value.

S132, acquiring a lower limit error value according to the actually measured accumulated electric quantity and the preset accumulated current error and the preset accumulated electric quantity in the SOC lower limit correction data, and determining the difference value between the preset SOC in the SOC lower limit correction data and the lower limit error value as an SOC lower limit threshold value.

For example, the BMS first processes the actual measured accumulated electric quantity and the preset accumulated current error and the preset accumulated electric quantity in the SOC upper limit correction data by using an upper limit error value calculation formula, so as to obtain an upper limit error value, wherein the upper limit error value calculation formula is wu=Du+k (C _T-Cu),C_T is the actual measured accumulated electric quantity, du and Cu are respectively the preset accumulated current error and the preset accumulated electric quantity in the SOC upper limit correction data, wu is the upper limit error value, and k is the accumulated electric quantity attenuation coefficient.

For example, the BMS firstly processes the preset accumulated current error and the preset accumulated historical electric quantity in the actually measured accumulated historical electric quantity and the SOC lower limit correction data by adopting a lower limit error value calculation formula to obtain a lower limit error value, wherein the lower limit error value calculation formula is that wp=dp+k (C _T-Cp),C_T is the actually measured accumulated historical electric quantity, dp and Cp are respectively the preset accumulated current error and the preset accumulated historical electric quantity in the SOC lower limit correction data, wp is a lower limit error value, and k is an accumulated historical electric quantity attenuation coefficient.

In one embodiment, step S14, that is, correcting the measured SOC by using the SOC upper limit threshold value and the SOC lower limit threshold value, obtains the target SOC, includes:

S141, if the measured SOC is larger than the SOC upper limit threshold value, determining the preset SOC in the SOC upper limit correction data as a target SOC.

S142, if the measured SOC is smaller than the SOC lower limit threshold value, determining the preset SOC in the SOC lower limit correction data as a target SOC.

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, determining the measured SOC as the target SOC.

As an example, if the measured SOC is greater than the SOC upper limit threshold, it is indicated that the measured SOC is greater than an acceptable error upper limit of the preset SOCu in the SOC upper limit correction data, and 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, so as to avoid an 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%, the upper limit error value is 2%, the SOC upper limit threshold value is 87%, and 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%.

As an example, if the measured SOC is smaller than the SOC lower limit threshold, it is indicated that the measured SOC is smaller than the lower limit of the error acceptable by the preset SOCp in the SOC lower limit correction data, and 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, so as to avoid the 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 value is 73%, the SOC _T is 71%, the preset SOCp in the SOC lower limit correction data is determined as the target SOC, and the target SOC is 75%.

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, which means that the measured SOC is not less than the lower error limit acceptable by the preset SOCp in the SOC lower limit correction data and the measured SOC is not greater than the upper error limit acceptable by the preset SOCu in the SOC upper limit correction data, the measured SOC is directly determined as the target SOC, so that the accuracy of the target SOC can be ensured, and the error between the measured SOC and the actual SOC of the battery is smaller. For example, if the SOC lower limit threshold value is 73% and the SOC upper limit threshold value is 87%, the measured SOC is 80% and 73% <80% <87%, the measured SOC is directly determined as the target SOC, that is, the target SOC is 80%, and no correction is necessary.

According to the battery SOC estimation method, according to the correction data table which is inquired according to the actual measured current and the actual measured voltage in the actual measured data of the battery, the SOC upper limit correction data and the SOC lower limit correction data are quickly determined from the limited configuration correction data, so that the SOC estimation requires low resources and is beneficial to providing instantaneity of SOC estimation, the SOC upper limit threshold and the SOC lower limit threshold are determined based on the actual measured accumulated historical electric quantity, the SOC upper limit correction data and the SOC lower limit correction data, the actual measured SOC is corrected by utilizing the SOC upper limit threshold and the SOC lower limit threshold, the output target SOC is high in accuracy, and the error with the actual SOC of the battery is small, so that the SOC estimation can meet the requirements of high accuracy, low resource requirements and high instantaneity.

In one embodiment, the battery measured data further includes a measured accumulated current error. As shown in fig. 2, after step S11, that is, after acquiring the battery measured data, the battery SOC estimation method further includes:

s21, comparing the actually measured accumulated current error with a current error tolerance value.

S22, if the actually measured accumulated current error is larger than the current error tolerance value, inquiring a correction data table according to the actually measured current and the actually measured voltage, and acquiring SOC upper limit correction data and SOC lower limit correction data matched with the actually measured current and the actually measured voltage.

And S23, if the actually measured accumulated current error is not larger than the current error tolerance value, updating configuration correction data in a correction data table based on the actually measured data of the battery.

Further, the battery measured data also includes a measured accumulated current error. The measured accumulated current error refers to the accumulation of all error electric quantities after receiving the measured data of the battery, and can be represented by D _T. It will be appreciated that the measured accumulated current error includes the sum of all the error amounts before the system time and the accumulation of the error amounts formed by the current battery measured data. The error charge amount is understood herein as an error between the measured SOC and the actual SOC of the battery.

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.

As an example, the BMS compares the actually measured accumulated current error with a preset current error tolerance value, if the actually measured accumulated current error is greater than the current error tolerance value, steps S12-S14 are executed to realize correction processing on the actually measured SOC and output a target SOC to ensure the accuracy of the target SOC, and if the actually measured accumulated 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 actually measured data of the battery to realize updating the configuration correction data in the correction data table according to the actual running condition of the battery so as to ensure the accuracy and instantaneity of the configuration correction data in the correction data table.

In this embodiment, due to the fact that the physical condition of the battery changes in real time during the actual running process of the battery, such as the conditions of aging of the battery, reduction of the total capacity of the battery, or abnormal increase of the internal resistance, configuration correction data in a correction data table stored in a memory of the BMS when leaving the factory reduces the accuracy of estimating the SOC of the battery with the physical condition change, when the actually measured accumulated current error in the actually measured data of the battery is not greater than the current error tolerance value, the configuration correction data in the correction data table is updated based on the actually measured data of the battery, which is helpful for improving the accuracy of estimating and correcting the SOC of the subsequently acquired actually measured data of the battery.

Since the current value can evaluate the index of decreasing the maximum difference, the accumulated current error is an index for evaluating the deviation of the historical current from the preset current. Therefore, based on the actually measured current, actually measured accumulated current error and actually measured accumulated historical electric quantity in the actually measured data of the battery, unreliable calculation can be carried out on different preset currents in all configuration correction data with the same preset SOC and actually measured SOC, actually measured unreliable values of actually measured data of the battery are obtained, and whether the configuration correction data in a correction data table need to be updated by adopting the actually measured data of the battery is determined according to the actually measured unreliable values.

In one embodiment, the measured data of the battery includes measured SOC, measured current, measured voltage, measured accumulated current error and measured accumulated historical electric quantity, which can be represented by [ SOC _T、I_T、V_T、D_T、C_T ], and the configuration correction data includes preset current, preset voltage, preset SOC, preset accumulated current error and preset accumulated historical electric quantity, which can be represented by [ SOCn, in, vn, dn, cn ]. Step S23, namely updating the configuration correction data in the correction data table based on the battery actual measurement data, includes:

S231, acquiring initial SOC correction data of all the SOCs matched with the actual SOCs in the correction data table, determining initial SOC correction data with preset current adjacent to the actual current as first to-be-updated correction data and second to-be-updated correction data, determining the first to-be-updated correction data and the second to-be-updated correction data as SOC to-be-updated correction data, wherein the preset current in the first to-be-updated correction data is smaller than the actual current, and the preset current in the second to-be-updated correction data is larger than the actual current.

S232, processing the battery actual measurement data and the SOC correction data to be updated, and obtaining an actual measurement unreliable value corresponding to the battery actual measurement data and an unreliable value to be updated corresponding to the SOC correction data to be updated.

And S233, if the actually measured unreliable value is smaller than the unreliable value to be updated, updating the correction data to be updated of the SOC by adopting the actually measured data of the battery.

As an example, step S231 specifically includes (1) comparing preset SOCs in all configuration correction data in the correction data table, and determining configuration correction data with the preset SOCs matched with the actually measured SOCs as SOC primary selection correction data. For example, the configuration correction data in which the preset SOC and the measured SOC are equal to each other is determined as the SOC preliminary selection correction data, or the configuration correction data in which the preset SOC and the measured SOC are closest to each other is determined as the SOC preliminary selection correction data. (2) And determining the initial selection correction data of the SOC adjacent to the preset current and the actually measured current as the screening correction data of the SOC. For example, preset currents and actual currents in all the SOC initial selection correction data are ordered to form a current ordering sequence, the SOC initial selection correction data corresponding to two preset currents adjacent to the actual currents in the current ordering sequence, namely, the SOC initial selection correction data corresponding to two preset currents before and after the actual currents in the current ordering sequence are respectively determined to be first correction data to be updated and second correction data to be updated, the first correction data to be updated and the second correction data to be updated are determined to be SOC screening correction data, so that whether the SOC correction data to be updated need to be updated is determined according to the actual measurement data of the battery and the SOC correction data to be updated or not, and accuracy of a subsequent battery SOC estimation algorithm is guaranteed. The preset current in the first correction data to be updated is smaller than the actual current, that is, the initial SOC correction data corresponding to the preset current with the smallest difference value of the actual currents is the first correction data to be updated. And the preset current in the second correction data to be updated is larger than the actual measurement current, namely, the initial SOC correction data corresponding to the preset current with the smallest difference value of the actual measurement currents is the second correction data to be updated in all the preset currents larger than the actual measurement current.

As an example, step S232 specifically includes processing the measured data of the battery by using an unreliable value formula to obtain a measured unreliable value corresponding to the measured data of the battery, processing the corrected data of the SOC to be updated by using an unreliable value formula to obtain a to-be-updated unreliable value corresponding to the corrected data of the SOC to be updated, where the unreliable value formula is Q (CTBm) =ABS (Io-CTBm) +Do+g+ (C _T -Co) ×h, Q (CTBm) is an unreliable value corresponding to a preset current CTBm, and is a measured unreliable value or to-be-updated unreliable value, ABS is an absolute function, io is a current used for calculating the unreliable value, is a measured current I _T or a preset current In, f is a current coefficient, do is an accumulated current error used for calculating the unreliable value, and can be an accumulated current error D _T or a preset accumulated current error Dn, and Co is an accumulated current error coefficient used for calculating the unreliable value, cn is a current used for calculating the unreliable value, and Cn is a current history electric quantity used for calculating the accumulated electric quantity. Understandably, f, g, and h can be determined empirically by the user.

In an embodiment, step S232, namely, processing the actually measured data of the battery and the correction data to be updated of the SOC, to obtain an actually measured unreliable value corresponding to the actually measured data of the battery and an unreliable value to be updated corresponding to the correction data to be updated of the SOC, includes:

S2321, calculating the measured data of the battery by adopting a measured unreliable value formula Q _T(CTBm）=ABS（I_T-CTBm)*f+D_T*g+(C_T-C_T) h, and obtaining a measured unreliable value corresponding to the measured data of the battery.

S2322, calculating the to-be-updated correction data of the SOC and the actually measured data of the battery by adopting an unreliable value formula Qn (CTBm) =ABS (In-CTBm) ×f+Dn×g+ (C _T -Cn) ×h to obtain an unreliable value to be updated corresponding to the to-be-updated correction data of the SOC.

Wherein Q _T (CTBm) is an actual measurement unreliable value corresponding to actual measurement data of the battery, CTBm is preset current, ABS is an absolute function, I _T、D_T and C _T are actual measurement current, actual measurement accumulated current error and actual measurement accumulated historical electric quantity In the actual measurement data of the battery respectively, qn (CTBm) is an unreliable value to be updated corresponding to correction data to be updated of the SOC, in, dn and Cn are preset current, preset accumulated current error and preset accumulated historical electric quantity corresponding to correction data to be updated of the SOC respectively, f is a current coefficient, g is an accumulated current error coefficient, and h is an accumulated historical electric quantity coefficient.

The following illustrates a procedure of updating configuration correction data:

Let the preset SOC be 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, and the coefficients are not exactly coefficients in actual use, and can be adjusted according to the battery and the project conditions, for example. In the initial state, 5 pieces of configuration correction data are acquired as follows:

Ctb1=0.2c: empty;

Ctb2=0.7c: empty;

ctb3=1.2c: empty;

ctb4=1.7c: empty;

ctb5=2.2c: empty;

when the measured SOC reaches 75 and the measured accumulated current error is not greater than the current error tolerance value (e.g., 2%), the 1 st battery measured data [75%,1.0c,3.356,3ah,28000ah ] is obtained, and since CTB2<1.0c < CTB3, the configuration correction data corresponding to CTB2 and CTB3 are SOC correction data to be updated, where the configuration correction data corresponding to CTB2 is the first correction data to be updated and the configuration correction data corresponding to CTB3 is the second correction data to be updated, and since the two SOC correction data to be updated are empty in the initial state (1), the SOC correction data to be updated can be directly updated by using the battery measured data, and the 5 configuration correction data are obtained as follows:

Ctb1=0.2c: empty;

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

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

ctb4=1.7c: empty;

ctb5=2.2c: empty;

When the measured SOC reaches 75% and the measured accumulated current error is not greater than the current error tolerance value (e.g., 2%), the 2 nd battery measured data [75%,0.3c,3.356,3ah,28000ah ] is obtained, and since CTB1<0.3c < CTB2, the configuration correction data corresponding to CTB1 and CTB2 are SOC to-be-updated correction data, where the configuration correction data corresponding to CTB1 is the first to-be-updated correction data, the configuration correction data corresponding to CTB2 is the second to-be-updated correction data, and according to the formula of the unreliable value, 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 are respectively obtained as follows:

the unreliable value to be updated corresponding to the correction data to be updated of the SOC is as follows:

Ctb1=0.2c: empty;

Qn (CTB 1) is null;

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

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

The measured unreliable values corresponding to the measured data of the battery are as follows:

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

Q_T(CTB1)=(0.3–0.2)*1000+3*10+(28000–28000)*0.01=130;

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

Q_T(CTB2)=(0.7–0.3)*1000+3*10+(28000–28000)*0.01=430;

Since Qn (CTB 1) is empty, Q _T (CTB 1) =130, an update is required, and since Qn (CTB 2) =420 < Q _T (CTB 2) =430, no row update is required, the updated 5 configuration correction data are as follows:

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

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

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

ctb4=1.7c: empty;

ctb5=2.2c: empty;

When the measured SOC reaches 75% and the measured accumulated current error is not greater than the current error tolerance value (e.g., 2%), 3 rd battery measured data [75%,1.3c,3.458,5ah,30000ah ] are obtained, and since CTB3<1.3c < CTB4, configuration correction data corresponding to CTB3 and CTB4 are SOC to-be-updated correction data, wherein configuration correction data corresponding to CTB3 is first to-be-updated correction data, configuration correction data corresponding to CTB4 is second to-be-updated correction data, and according to an unreliable value formula, an unreliable value to be updated corresponding to the SOC to-be-updated correction data and an unreliable value to be measured corresponding to the battery measured data are respectively obtained as follows:

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

Qn(CTB3)=(1.2–1.0)*1000+6*10+(30000–22000)*0.01=340;

ctb4=1.7c, empty

Qn (CTB 4) is null;

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

Q_T(CTB3)=(1.3–1.2)*1000+5*10+(30000–30000)*0.01=150;

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

Q_T(CTB4)=(1.7–1.3)*1000+5*10+(30000–30000)*0.01=450;

Since Qn (CTB 3) =340 > Q _T (CTB 3) =150, and since Qn (CTB 4) is empty and Q _T (CTB 4) =450, and update is required, the updated 5 configuration correction data are as follows:

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

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

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

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

ctb5=2.2c: empty;

When the measured SOC reaches 75% and the measured accumulated current error is not greater than the current error tolerance value (e.g., 2%), obtaining the 4 th battery measured data [75%,1.9c,3.485,4ah,35000ah ], wherein the configuration correction data corresponding to CTB4 and CTB5 are SOC to-be-updated correction data, the configuration correction data corresponding to CTB4 is first to-be-updated correction data, the configuration correction data corresponding to CTB5 is second to-be-updated correction data, and 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 are respectively obtained according to an unreliable value formula as follows:

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

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

ctb5=2.2c: empty;

qn (CTB 4) is null;

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

Q_T(CTB4)=(1.9–1.7)*1000+4*10+(35000–35000)*0.01=240

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

Q_T(CTB5)=(2.2–1.9)*1000+4*10+(35000–35000)*0.01=340

since Qn (CTB 4) =530 > Q _T (CTB 4) =240, and since Qn (CTB 5) is empty and Q _T (CTB 5) =340, and update is required, the updated 5 configuration correction data are as follows:

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

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

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

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

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

and calculating the corresponding unreliable value to be updated by using the SOC to be updated correction data with the same SOC as the actual measured SOC, namely, obtaining the unreliable value to be updated corresponding to the SOC to be updated by using the preset accumulated current error and the preset accumulated historical electric quantity in the SOC to be updated correction data, and updating the SOC to be updated correction data by using the battery actual measurement data which is smaller than the actual measurement unreliable value of the unreliable value to be updated, so as to realize the real-time updating of the configuration correction data in the correction data table, ensure the reliability of the subsequent SOC estimation, and avoid the failure of accurately correcting the SOC by the configuration correction data prestored in the correction data table when the physical condition of the battery changes.

For example, in the first execution of steps S11 to S14, in processing the battery measured data corresponding to the measured current of 1.2C, two configuration correction data of [75%,1.0C, a, b, C ] and [75%,1.3C, e, F, G ] stored in advance in the correction data table are adopted as the SOC upper limit correction data and the SOC lower limit correction data, respectively, so as to determine the final target SOC. After updating [75%,1.0C, A, B, C ] to [75%,0.9C, A ', B', C '], the steps S11-S14 are subsequently performed again, it is necessary to validate the SOC upper limit correction data and the SOC lower limit correction data with two configuration correction data of [75%,0.9C, A', B ', C' ] and [75%,1.3C, E, F, G ], respectively, in order to determine the final target SOC.

In an embodiment, before executing step S11, a correction data table is predetermined, specifically, a preset SOC and a preset current in the correction data table are determined through experiments, so that the measured voltage, the measured accumulated current error and the measured accumulated historical electric quantity corresponding to the preset SOC and the preset current can be updated and obtained in real time according to the actual operating condition of the battery.

In one embodiment, a battery management system is provided, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, where the processor executes the computer program to implement the battery SOC estimation method in the above embodiment, such as S11-S14 shown in fig. 1 or S21-S23 shown in fig. 2, and the description thereof is omitted herein for avoiding repetition.

In an embodiment, a computer readable storage medium is provided, and a computer program is stored on the computer readable storage medium, and when the computer program is executed by a processor, the method for estimating the SOC of the battery in the above embodiment is implemented, for example, S11-S14 shown in fig. 1 or S21-S23 shown in fig. 2, which are not repeated herein.

Those skilled in the art will appreciate that implementing all or part of the above-described methods in accordance with the embodiments may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of 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), among others.

It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions.

It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present invention.

The foregoing embodiments are merely for illustrating the technical solution of the present invention, but not for limiting the same, and although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solution described in the foregoing embodiments may be modified or substituted for some of the technical features thereof, and that these modifications or substitutions should not depart from the spirit and scope of the technical solution 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, comprising:

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 step of 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 comprises:

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;

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.

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 the target SOC comprises:

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, wherein the battery measured data further includes a 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, wherein 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 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;

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 correction data to be updated to obtain the measured unreliable value corresponding to the battery measured data and the unreliable value to be updated corresponding to the SOC correction data to be updated comprises:

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 measured data of the battery to obtain the measured unreliable value corresponding to the measured data of the battery;

The unreliable value to be updated formula Qn(CTBm)=ABS(In-CTBm)*f+Dn*g+(C _T -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;

Among them, Q _T (CTBm) is the measured unreliable value corresponding to the battery measured data; CTBm is the preset current; ABS is the absolute value function; I _T , D _T and C _T are respectively the measured current, the measured cumulative current error and the measured cumulative historical power in the battery measured data; Qn (CTBm) is the unreliable value to be updated corresponding to the SOC to-be-updated correction data; In, Dn and Cn are respectively the preset current, the preset cumulative current error and the preset cumulative historical power corresponding to the SOC to-be-updated correction data; 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, wherein the processor implements the battery SOC estimation method as claimed in any one of claims 1 to 6 when executing the computer program.

8. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the battery SOC estimation method according to any one of claims 1 to 6.