Research of CDKF Based on Spectral Decomposition of Symmetric Matrix in SOC Estimation of Lithium-ion Cell

Lithium-ion battery has been widely used in various fields of social production. Because it contains complex electrochemical system, it is difficult to detect its states, which brings adverse effect to the power supply. This paper combined the Thevenin equivalent-circuit, spectral decomposition of symmetric matrix(covariance matrix) and central difference Kalman filtering(CDKF) to construct an estimation model of polymer lithium-ion cell's SOC, carried out experimental verification, and highlighted the effect of the model in error correction and state estimation by rough ampere-hour integrator.