State of Charge Estimation Based on Thermal Modeling Compensation Considering Capacity Variation by Internal Temperature Effects of LiFePO₄ Battery

This paper proposes a state-of-charge (SOC) estimation method based on the thermal modeling compensation considering the capacity loss of lithium-ion battery for internal temperature effects. The proposed method extracts the capacity for the operating temperature range and configures the temperature-capacity curve through curve fitting. In addition, an experimental thermal model is extracted to estimate the surface temperature generated by the internal conduction heat. The surface temperature and internal temperature deviation are compensated based on the extracted thermal model. The feasibility of the proposed method is verified by comparing the SOC estimation accuracy according to the temperature change of the lithium iron phosphate battery.