Optimal Battery Thermal Management During and Prior to Fast Charging using Dynamic Programming

Abstract

The rapid improvement of fast charging capabilities in battery electric vehicles (BEVs) has contributed to the widespread adoption of electric mobility. However, the promised charging time is often prolonged as the maximum fast charging current can only be reached when the battery temperature is in the optimal range. To address this challenge, it is essential to thermally precondition the battery while the vehicle is en route to the charging station. In this paper, a framework for calculating the optimal battery thermal management strategy during and prior to fast charging is introduced. To this end, driving and fast charging measurements are conducted using an electric vehicle on a chassis dynamometer that includes a high power charger. Subsequently, a model is outlined and the parameters are identified using the measurement data. By employing dynamic programming (DP), the optimal thermal management strategy with respect to minimal charging time is determined for a driving and fast charging scenario. Ultimately, the optimal thermal management strategy can serve as a benchmark for any online strategy, thereby enabling the identification of potential improvements.