A Fractional-Order Model of Lithium-Ion Batteries Considering Polarization in Electrolyte and Thermal Effect

With the growing demand of safety and accurate control for electric vehicles, it is urgent to develop a physics-based electrochemical model of lithium-ion battery with simple calculation and high accuracy over wide temperature range for application in battery management system (BMS). However, traditional electrochemical models are too complex to be applied in real usage, and most of them fail to capture thermal characteristics of the cell. Therefore, a fractional-order model of lithium-ion battery considering polarization in electrolyte and thermal effect (FOMeT) is proposed in this paper. The fractional-order model (FOM) is improved by considering the polarization in electrolyte. The particle thermal model is proposed to describe the heat generation and absorption of the cell. Finally, the FOM considering electrolyte polarization and the particle thermal model are combined to form FOMeT by coupling the cell temperature and dynamics of lithium-ion. The results show that the proposed model performs high voltage accuracy and temperature accuracy over wide temperature range (273.15K∼318.15K) and wide current load range (0.5C∼2C).