Closed-loop Optimal Ageing-Aware Charging of Li-ion Batteries Using a Surrogate Model

Abstract

Li-ion batteries offer the finest balance of performance, price, and longevity for efficient energy storage. One of the main features of the Battery Management System (BMS) is to yield the best trade-of between fast charging and ageing effects minimisation while meeting safety requirements. In this paper, we provide an online optimal-control-based strategy for ageing-aware charging. This is achieved by formulating a control problem where a surrogate model is exploited in the description of the battery behaviour, that minimizes the side reactions, while satisfying ageing-related and safety constraints. The surrogate model combines a static nonlinear model that depends on the state of charge with a black-box finite-dimensional linear-time-invariant model. The results are obtained in simulation with a DFN battery model considered as a real ”plant”. To close the loop, a Kalman Filter with a forgetting factor is employed to estimate the states. Finally, we will compare the Pareto-fronts obtained using the suggested optimal-control-based methodology with those obtained using an open-loop strategy.