A comparative study on fractional order models for voltage simulation of lithium ion batteries

Lithium ion battery models play an important role in the battery management system of electric vehicles. Recently, fractional order modelling has drawn more attention due to the high accuracy and adjustable computational burden. Plenty of fractional order battery models have been proposed for voltage simulation and state estimation. Although they have been proved to be more accurate than traditional equivalent circuit models, there is no study comparing existing fractional order models. In this work, fractional order models used for voltage simulation and state estimation in literature have been summarized and compared. They are identified under different temperatures and ageing statuses, and the parameterized models are then validated using different profiles. The computational burden is also analyzed to find the best fractional order model. The results show that not the most complex fractional order models originating from impedance spectra fitting is not applicable for time domain simulation, and the difference between impedance spectra fitting and time domain simulation can't be ignored.