Observer design for an electrochemical model of lithium ion batteries based on a polytopic approach

Abstract

Smart battery management systems require reliable state information, which is unavailable through direct measurements. Electrochemical models are relevant in this context as these describe the internal phenomena, which govern the battery These models can thus be used to design observers and hence to estimate the state variables on-line. We propose an electrochemical model of a lithium ion battery given by a set of ordinary differential equations built from the spatial discretisation of partial differential equations that locally describe mass and charge transport of the lithium. We then design an observer and analyse its stability via a polytopic approach, which relies on the satisfaction of linear matrix inequalities. The latter are shown to be verified for standard model parameters values. Simulation results on the original infinite-dimensional model are presented, which show the good performance of the observer.