CN-121978561-A - Lithium iron phosphate battery platform-stage SOC correction judging method and device and vehicle

CN121978561ACN 121978561 ACN121978561 ACN 121978561ACN-121978561-A

Abstract

The application provides a method, a device and a vehicle for correcting and judging a lithium iron phosphate battery in a platform stage SOC, and relates to the technical field of vehicles, wherein the method comprises the steps of determining deviation between an SOC value corresponding to the current charge or discharge capacity in the platform stage and an SOC value corresponding to energy as a first deviation; and determining the SOC deviation according to the first deviation and the second deviation, and sending an early warning signal for executing SOC correction when the SOC deviation exceeds a deviation threshold value. According to the application, the accumulated degree of the deviation of the current lithium iron phosphate battery in the platform phase is better analyzed through the deviation between the SOC determined by the capacity and the energy, the second deviation introduced by the sampling of the current sensor is additionally considered, the source of the SOC deviation is covered as much as possible, the accuracy and the nature of the deviation analysis are improved, and the timeliness of the subsequent starting correction is ensured.

Inventors

LI XIN
ZHANG BEI
Du can
YANG LIANG

Assignees

东软睿驰汽车技术（沈阳）有限公司

Dates

Publication Date: 20260505
Application Date: 20260210

Claims (10)

1. The method for judging the SOC correction in the platform phase of the lithium iron phosphate battery is characterized by comprising the following steps of: Determining a deviation between an SOC value corresponding to a current charge or discharge capacity and an SOC value corresponding to energy in a platform period as a first deviation; determining a current sensor deviation accumulated value of the current sensor in the platform period sampling process as a second deviation; And determining the SOC deviation according to the first deviation and the second deviation, and sending an early warning signal for executing SOC correction when the SOC deviation exceeds a deviation threshold.
2. The method of claim 1, wherein determining the deviation between the SOC value corresponding to the capacity and the SOC value corresponding to the energy currently charged or discharged during the plateau comprises: and accumulating the charging deviation between the SOC value corresponding to the charging capacity and the SOC value corresponding to the charging energy and the discharging deviation between the SOC value corresponding to the discharging capacity and the SOC value corresponding to the discharging energy in each plateau period from the last execution of the SOC correction, and determining the first deviation corresponding to the current SOC.
3. The method according to claim 2, wherein the method for calculating the charging deviation of the charging capacity and the charging energy per charging comprises: Determining a corresponding charging capacity of the charging in the platform period at the temperature of the charging based on the current sampling value and the ampere-hour integral; Determining a capacity SOC value corresponding to the charging in the platform period according to a first corresponding relation between the charging capacity and the temperature at which the charging is positioned, wherein the first corresponding relation is a corresponding relation between the charging capacity and the SOC value in the platform period; Determining the corresponding charging energy of the charging in the platform period at the temperature of the charging based on the current sampling value, the voltage sampling value and the watt-hour integral; Determining an energy SOC value corresponding to the charging in the platform period according to a second corresponding relation between the charging energy and the temperature at which the charging is positioned, wherein the second corresponding relation is a corresponding relation between the charging energy in the platform period and the SOC value in the platform period; and the difference value between the capacity SOC value and the energy SOC value is the charging deviation.
4. The method according to claim 3, wherein the method for calculating the discharge deviation between the SOC value corresponding to the discharge capacity per discharge and the SOC value corresponding to the discharge energy comprises: Determining the corresponding discharge capacity of the discharge in the plateau period based on the current sampling value and the ampere-hour integral; Determining a capacity SOC value corresponding to the discharge in the plateau according to a third corresponding relation between the discharge capacity and the temperature at which the discharge is located, wherein the third corresponding relation is a corresponding relation between the discharge capacity and the SOC value in the plateau; determining the corresponding discharge energy of the discharge in the plateau period based on the current sampling value, the voltage sampling value and the watt-hour integral; determining an energy SOC value corresponding to the discharge in the plateau according to a fourth corresponding relation between the discharge capacity and the temperature at which the discharge is positioned, wherein the fourth corresponding relation is a corresponding relation between the discharge energy and the SOC value in the plateau; and the difference value between the capacity SOC value and the energy SOC value is the discharge deviation.
5. The method of claim 1, wherein determining the current sensor bias accumulated value of the current sensor during the plateau sampling as the second bias comprises: the second deviation is obtained by accumulating the current sensor deviation accumulation value of charge or discharge in each plateau period since the last execution of SOC correction.
6. The method according to claim 5, wherein the calculation method of the current sensor bias accumulated value of the charge or discharge in each plateau is: under the condition of charging, determining a first product of a current sampling deviation value and the duration of charging in a platform period, and determining a second product of a capacity value and the state of health of a battery; determining the ratio of the first product to the second product as the current sensor deviation accumulated value, wherein the current sampling deviation value is a positive deviation value corresponding to a current sampling value at the temperature corresponding to the charging; In the case of discharge, determining a third product of the current sampling deviation value and the duration of the discharge in the plateau period, and determining a fourth product of the capacity value and the battery state of health; determining the ratio of the third product to the fourth product as the current sensor deviation accumulated value, wherein the current sampling deviation value is a negative deviation value corresponding to a current sampling value at the temperature corresponding to the discharge; the capacity value is a value determined according to the SOC value based on the corresponding temperature.
7. The method of claim 1, wherein the method of determining the plateau comprises: determining a state of charge (SOC) -Open Circuit Voltage (OCV) curve according to charge and discharge of the lithium iron phosphate battery; Determining a platform period threshold according to the target SOC precision and the voltage sampling precision; and on the SOC-OCV curve, a section corresponding to the ratio of the SOC to the OCV being greater than the platform period threshold is a platform period.
8. The method of claim 7, wherein the method further comprises: under the condition that the lithium iron phosphate battery is charged to the platform stage, calculating the current charge capacity based on a current sampling value and ampere-hour integral, and determining the current SOC value based on a first corresponding relation of the temperature where the charge is positioned, wherein the first corresponding relation is the corresponding relation between the charge capacity and the SOC value in the platform stage; And under the condition that the lithium iron phosphate battery is discharged to the plateau period, calculating the current discharge capacity based on a current sampling value and ampere-hour integral, and determining the current SOC value based on a third corresponding relation of the temperature where the discharge is located, wherein the third corresponding relation is the corresponding relation of the discharge capacity and the SOC value in the plateau period, or calculating the discharge energy in the plateau period based on the current sampling value, the voltage sampling value and the watt-hour integral, and determining the current SOC value based on a fourth corresponding relation of the temperature where the discharge is located, wherein the fourth corresponding relation is the corresponding relation of the discharge energy and the SOC value in the plateau period at the discharge temperature.
9. The utility model provides a lithium iron phosphate battery platform phase SOC correction judgement device which characterized in that includes: A first processing unit, configured to determine, as a first deviation, a deviation between an SOC value corresponding to a capacity currently charged or discharged in a plateau and an SOC value corresponding to energy; A second processing unit for determining a current sensor bias accumulated value of the current sensor during the sampling in the platform period as a second bias; And the analysis unit is used for determining the SOC deviation according to the first deviation and the second deviation, and sending an early warning signal for executing SOC correction when the SOC deviation exceeds a deviation threshold value.
10. A vehicle, characterized in that a method for determining SOC correction in a plateau of a lithium iron phosphate battery according to any one of claims 1 to 8 is employed, wherein the sending of an early warning signal for performing SOC correction includes: and sending a signal indicating that the vehicle is fully charged to the battery management system until the vehicle is fully charged.

Description

Lithium iron phosphate battery platform-stage SOC correction judging method and device and vehicle Technical Field The application relates to the technical field of vehicles, in particular to a method and a device for correcting and judging the platform-stage SOC of a lithium iron phosphate battery and a vehicle. Background The SOC calculation difficulty coefficient of the lithium iron phosphate battery is large, the voltage of the lithium iron phosphate battery is mainly reflected in a platform period, the voltage fluctuation is small when the SOC changes in the period, the linearity requirement is not met, the traditional battery meeting the linearity requirement is inaccurate in calculation by adopting a traditional SOC calculation method (such as combination of Kalman filtering and ampere-hour integral calculation, and the like), and further, correction is carried out only when the SOC deviation is large, and the correction is not timely. Disclosure of Invention In view of the above, the application provides a method and a device for judging the calibration of the lithium iron phosphate battery in the stage of SOC and a vehicle, aiming at improving the timeliness of the calibration of the lithium iron phosphate battery in the stage of SOC. In a first aspect, the application provides a method for correcting and judging the stage SOC of a lithium iron phosphate battery, which comprises the following steps: Determining a deviation between an SOC value corresponding to a current charge or discharge capacity and an SOC value corresponding to energy in a platform period as a first deviation; determining a current sensor deviation accumulated value of the current sensor in the platform period sampling process as a second deviation; And determining the SOC deviation according to the first deviation and the second deviation, and sending an early warning signal for executing SOC correction when the SOC deviation exceeds a deviation threshold. Optionally, the determining the deviation between the SOC value corresponding to the current charge or discharge capacity and the SOC value corresponding to the energy in the plateau period includes: and accumulating the charging deviation between the SOC value corresponding to the charging capacity and the SOC value corresponding to the charging energy and the discharging deviation between the SOC value corresponding to the discharging capacity and the SOC value corresponding to the discharging energy in each plateau period from the last execution of the SOC correction, and determining the first deviation corresponding to the current SOC. Optionally, the method for calculating the charging deviation between the charging capacity and the charging energy of each charging includes: Determining a corresponding charging capacity of the charging in the platform period at the temperature of the charging based on the current sampling value and the ampere-hour integral; Determining a capacity SOC value corresponding to the charging in the platform period according to a first corresponding relation between the charging capacity and the temperature at which the charging is positioned, wherein the first corresponding relation is a corresponding relation between the charging capacity and the SOC value in the platform period; Determining the corresponding charging energy of the charging in the platform period at the temperature of the charging based on the current sampling value, the voltage sampling value and the watt-hour integral; Determining an energy SOC value corresponding to the charging in the platform period according to a second corresponding relation between the charging energy and the temperature at which the charging is positioned, wherein the second corresponding relation is a corresponding relation between the charging energy in the platform period and the SOC value in the platform period; and the difference value between the capacity SOC value and the energy SOC value is the charging deviation. Optionally, the method for calculating the discharge deviation between the SOC value corresponding to the discharge capacity of each discharge and the SOC value corresponding to the discharge energy includes: Determining the corresponding discharge capacity of the discharge in the plateau period based on the current sampling value and the ampere-hour integral; Determining a capacity SOC value corresponding to the discharge in the plateau according to a third corresponding relation between the discharge capacity and the temperature at which the discharge is located, wherein the third corresponding relation is a corresponding relation between the discharge capacity and the SOC value in the plateau; determining the corresponding discharge energy of the discharge in the plateau period based on the current sampling value, the voltage sampling value and the watt-hour integral; determining an energy SOC value corresponding to the discharge in the plateau according to a fourth correspondin