Dynamic calibration method of electric automobile power battery SOC

Abstract

The invention discloses a dynamic calibration method of an electric automobile lithium ion battery SOC. The method includes the following steps that an OCV-SOC list is obtained and stored through an open circuit voltage method, and vehicle standing threshold time is preset; if vehicle standing time is longer than the threshold time, the current single voltage of a vehicle is obtained, and if the vehicle standing time is shorter than or equal to the threshold time, a battery management system does not act; and the battery management system searches the OCV-SOC list according to the current single voltage for an SOC value needing to be calibrated, the current SOC value and the SOC value obtained through the search of the list are recorded, the SOC deviation between the current SOC value andthe SOC value obtained through the search of the list is calculated, and the battery management system uses an SOC algorithm with dynamic calibration for conducting dynamic calibration on the batterySOC. By the adoption of the dynamic calibration method of the SOC, the SOC deviation is recorded and not calibrated in the vehicle standing process according to the battery single voltage, a static error is complemented to the battery SOC in proportion in the vehicle operation process, the SOC jumping change caused by SOC static calibration is avoided, the client misunderstanding that large powerconsumption or electric quantity counterfeit happens in the vehicle standing process is avoided, and the method is only achieved through a software algorithm of the battery management system.

Description

technical field [0001] The invention belongs to the technical field of lithium battery calibration, and in particular relates to a dynamic calibration method for the SOC of an electric vehicle power battery. Background technique [0002] With the promotion and popularization of new energy vehicles, more and more attention has been paid to electric drive vehicles. Due to the characteristics of high specific energy, light weight and long life, lithium-ion batteries are widely used in electric vehicles. The battery management system needs to display and report accurate battery power (SOC) at all times, so that the vehicle controller can accurately calculate the cruising range and control the output of battery energy. [0003] At present, the commonly used SOC estimation method is to use the ampere-hour integration method and the Kalman algorithm. The ampere-hour integration method uses the integration method to obtain the power SOC at a certain moment 0 As the initial power, ...

AI Technical Summary

Problems solved by technology

Although the error caused by the ampere-hour integral method and the Kalman algorithm can be eliminated by the open circuit voltage method, it is precisely because of this static calibration method that the SOC of the electric vehicle is inconsistent before and after resting, and the SOC static calibration value after charging will be smaller than the current one. value, and the SOC static calibration value after discharge will be greater than the current value. This difference in SOC makes customers subjectively think that there is a large power loss or power fraud when the electric vehicle is still.

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