Identification of Fractional Differential Models for Lithium-ion Polymer Battery Dynamics

This paper presents a non-integer order (fractional) derivative model for modeling lithium-ion (Li-ion) battery dynamics in which direct continuous-time (CT) model identification methods are used to estimate the battery model parameters. In particular, the CT least squares-based state-variable filter (lssvf) identification method is extended to be used in fractional differential model identification of a battery system. The model performance and validation accuracy are evaluated on the basis of experimental data of a Li-ion polymer (LiPo) battery. It is shown how the proposed lssvf identification method can accurately capture the fractional order battery dynamics and exhibit better performance than integer order differential models.