Available Capacity Estimation of Electric Vehicle Batteries Based on Peukert Equation at Various Temperatures

Abstract

Electric vehicles (EVs) are becoming widely used for its low energy consumption and low pollution. An accurate estimation of available capacity for Li-ion batteries has an important utility significance to optimize its performance in the applications of EVs. The Peukert equation is applied to estimate the available capacity of batteries. However, the fact that the available capacity of Li-ion batteries is dependent on battery temperatures can result in errors while using the Peukert equation. To address this problem, this paper proposes an extended Peukert equation to include temperature effect. This method considers battery temperature as an input variable into the Peukert equation. Experiments based on Li-ion batteries are carried out under various current and temperatures. The comparison of the estimated and the actual available capacity indicates that the proposed algorithm can provide a reliable and accurate estimation of the available capacity for Li-ion batteries.