LAUSR

Abstract This work introduces and compares low-computational cost MPC-based algorithms based on a reduced-order electrochemical model, the Equivalent Hydraulic Model (EHM), for the fast charge and balance of a string of battery cells accounting for degradation-related phenomena. The balance is carried out through a fully shunting grid. The shunting scenarios are described in two different approaches, namely: binary variables and pulse with modulation (PWM). Due to the complexity of solving nonlinear and non-convex constrained optimal problems, we approximate the balancing grid configurations of the string as subsystems to solve an optimization problem that follows the maximization over current and configuration of the string, while minimizing the charging current of each subsystem. Numerical results show that a PWM-based approach outperforms a mixed-integer approach, showing a charging time three times lower.