Calculation Method of Lithium Power Battery Internal Resistance Based on Freedom Model

Abstract

Lithium power battery as the power source of the electric vehicle in series and parallel way, due to the performances of each monomer battery are inconsistent, it will seriously influence on the performance of the battery charges and discharges, and the incomplete consistency of the battery internal resistance is one of the reasons that affect these differences. In order to obtain the internal resistance of electric vehicle lithium power battery accurately, this article uses the FreedomCAR equivalent circuit model, adopting multiple linear regression algorithm which based on LINEST function. And the model and algorithm are verified and tested, the experimental results show that if adjusting the polarization time parameter constantly, we may reduce the estimation error, and we can calculate the internal resistance of the battery accurately. © 2014 SERSC.