State of Charge Estimation for a Series Connected Lithium Ion Supercapacitor Module

In this paper, a state of charge estimation method for a series connected lithium ion supercapacitor module is carried out. Lithium ion supercapacitor module is modeled by an equivalent circuit model. The state of charge of the cell is estimated based on the extended Kalman filter. Considering the inconsistency of the cells in the module, a module level SOC estimation method is proposed based on a weighting factor strategy. According to the experimental results, the error of the supercapacitor module SOC estimation method is less than 4%.