Optimal power management for a series hybrid electric vehicle cognizant of battery mechanical effects

This paper presents an optimal power management strategy for a series hybrid electric vehicle (SHEV) with the consideration of battery bulk mechanical stress. The relation between mechanical stress and state-of-charge (SOC) is characterized first. Then, this relation is used to penalize the battery usage leading to capacity fade due to particle fracture in the negative electrode. The optimal power management strategy is found using Dynamic Programming (DP) not only for maximizing fuel economy but also for minimizing the battery cumulative bulk mechanical stress. DP results suggest that battery SOC needs to be regulated around a lower value for prolonged battery life. Moreover, it is found that the cumulative bulk mechanical stress can be significantly reduced at a small expense of fuel economy.