Systematic Derivation and Tuning of a Compact Differential-Algebraic Equations Model for LiFePO4-Graphite Li-Ion Batteries

Abstract

This paper presents a procedure for deriving and tuning a compact differential-algebraic equation (DAE) model for the LiFePO4-graphite lithium-ion battery cell. A reduced order model can drastically decrease the simulation time with a minimal loss of the prediction accuracy for the Li-ion battery. This paper proposes a method for choosing a Galerkin formulation that will produce a compact and solvable DAE system from the original higher-order model of the Lithium-ion battery cell. Moreover, a systematic tuning of the model parameters using the global optimization method is demonstrated by exploiting the computational efficiency of the simplified model. When coupled with the model for describing the hysteresis of the battery cell, the tuned model, consisting of 24 DAEs, shows a good agreement with the experimental data from a LiFePO4-graphite battery cell at rates up to 4C.