Predictive Fast Charging of Lithium-ion Battery with Electro-thermal Constraints

Lithium-ion batteries (LIBs) are widely used in electric vehicles (EVs) attributed to their advantages of high energy density and long cycle life. In this vision, fast charging of the LIB system has been a crucial technology to promote the large-scale penetration of EVs in the existing automotive market. Motivated by this, a thermal-constrained fast charging method is proposed based on the model predictive control (MPC) concept in this paper. A coupled electro-thermal model is established, based on which two model-based observers are devised to estimate the state of charge (SOC) and internal temperature of LIB. On this premise, an MPC-based controller is exploited to trade-off smartly the charging fastness and the physical constraints. Comparative results show that the proposed method can optimize the charging towards high speed while keep the terminal voltage and battery internal temperature both within the safety region, which forms an obvious superiority over the traditionally-used constant-current-constant-voltage (CC-CV) protocol.