Lithium ion battery state-of-charge estimation method based on disturbance observer

Abstract

The invention relates to the technical field of battery management systems, in particular to a lithium ion battery state-of-charge estimation method based on a disturbance observer, a battery state estimation model is established through a lithium ion battery first-order equivalent circuit model, errors existing in the first-order equivalent circuit model are corrected in real time through the disturbance observer, and the lithium ion battery state-of-charge estimation method based on the disturbance observer is obtained, a battery voltage disturbance observer model is established, the battery state estimation model is combined with the battery voltage disturbance observer model to obtain a battery state equation and a battery observation equation, and a Kalman gain matrix is obtained by adopting an extended Kalman filtering algorithm according to the battery state equation and the battery observation equation, according to the battery state equation, the battery observation equation and the Kalman gain matrix, the battery state-of-charge of the lithium ion battery is estimated, the problem that the precision of the SOC estimation result is reduced along with the increase of the battery use time and / or the cycle use frequency is solved, and the method is suitable for estimating the state-of-charge of the lithium ion battery.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to a method for estimating the state of charge of the lithium ion battery based on a disturbance observer. Background technique [0002] The commonly used estimation method for the state of charge (State of Charge, SOC) of lithium-ion batteries is the ampere-hour integral method based on the definition of SOC. Accumulative errors are easy to occur in the estimation process. Therefore, in order to reduce the estimation error of the state of charge, the SOC estimation method of the battery model combined with the Kalman filter algorithm is adopted. This method has higher requirements on the accuracy of the battery model parameters, and the battery model parameters The difference from the actual parameters will directly lead to a decrease in the accuracy of the estimation results. [0003] The battery model parameters are generally obtained from the battery standardized test data, and the firs...

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Problems solved by technology

[0004] The technical problem solved by the present invention is to provide a method for estimating the state of charge of a lithium-ion battery based on a disturbance observer, which solves the problem that the accuracy of the SOC estimation result decreases with the increase of battery service time and / or cycle times

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