Abstract

Abstract-Accurate prediction of the battery electrochemical dynamics is important to avoid undesired battery operation under aggressive driving. This paper proposes a battery power management strategy considering Li-ion concentration in the electrodes to prevent excessive battery charging and discharging. The proposed approach adjusts the allowable battery power limits through the feedback of the estimated electrode-averaged Li-ion concentration information. An advanced hybrid electric vehicle (HEV) power split strategy is constructed implementing a Li-ion battery model with electrochemical diffusion dynamics to capture the battery dynamic behavior under transients. A novel contribution arises from the implementation of an extended Kalman filter (EKF) using uneven discretization of the particle radius for fast and accurate prediction of the Lithium intercalation dynamics. The control design modifies the allowable battery power limit used in the supervisory controller, thus, maintaining low complexity of the control structure. I. INTRODUCTION ONTROL design of hybrid electric vehicle (HEV) or plug-in HEV (PHEV) is important to obtain the maximum hardware potential and to prevent battery degradation. The supervisory control affects battery operations regardless of HEV configurations: series HEV, parallel HEV, and power-split HEV. In the series HEV, propulsion power is entirely dependent on electric power, and the electric power is only delivered by the battery and the generator. Thus, supervisory controller must manage the electricity requirement for each electric component to achieve the desired performance and to prevent the possible abnormal operations. The current levels are generally high. Recently, Lithium-ion (Li-ion) batteries have been used in the electric vehicle (EV) and (P)HEV due to its high energy density. However, Li-ion battery is less durable than other types of rechargeable batteries, such as nickel metal hydride or nickel-cadmium designs. Thus, preventing overcharging and discharging is critical for improving the battery life and stability. Electrochemical models of the Li-ion battery were developed by Doyle et al.