Lithium ion battery SOC estimation method based on time-varying correction extended Kalman filtering

Abstract

The invention relates to a lithium ion battery SOC estimation method based on time-varying correction extended Kalman filtering, which is characterized in that linear processing is carried out by utilizing a Taylor expansion on the basis of a Kalman filtering algorithm, so that Kalman filtering can be applied to SOC estimation of a lithium ion battery pack with a nonlinear relationship; effective iterative calculation of the SOC value of the lithium ion battery pack is realized, and an SOC initial value error and an accumulated error existing in an ampere-hour integral are overcome; it is considered that internal parameters of the model are not constant due to influence of various factors, a function relationship between the SOC and each parameter is obtained through a curve fitting method, and is applied in an algorithm; a Thevenin equivalent circuit model is established, errors caused by the polarization effect are overcome, the steps are short, the principle is clear, the method is suitable for transient analysis of power type battery charging and discharging, and a better characterization effect on the battery is achieved; the method is based on an equivalent model circuit on the basis of fully considering the grouping work of the lithium ion batteries.

Description

technical field [0001] The invention relates to a lithium-ion battery SOC estimation method based on time-varying correction extended Kalman filter. The method aims at accurately estimating the SOC value of lithium-ion battery packs, and proposes a lithium-ion battery SOC estimation method based on time-varying correction extended Kalman filter. The battery SOC estimation method, through the first-order linearization of the Taylor expansion of the nonlinear function on the basis of the traditional Kalman filter algorithm, thereby transforming the nonlinear problem into a linear problem, can be applied to lithium-ion batteries with nonlinear relationships Pack SOC estimation; considering the influence of the internal parameters of the model by the SOC value, the functional relationship between SOC and each parameter is calculated and applied in the algorithm, which realizes the effective iterative calculation of the SOC value of the lithium-ion battery pack, and overcomes the er...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the shortcomings of the existing lithium-ion battery pack SOC estimation method, provide a lithium-ion battery pack SOC estimation method based on time-varying correction extended Kalman filter, and solve the problem of accurate estimation of the SOC value in lithium-ion battery pack applications question

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