Lithium ion Power Battery Internal Resistance Model and Its Experiment Study

Abstract:

According to the porous electrode theory, a simulation model of lithium ion power batteries is established. The preliminary analysis of the model indicates that the internal factors which affect the battery internal resistance is the solid phase diffusion coefficient of the electrodes and electronic conductivity, ion conductivity and electrodes conductivity of the battery. The Galvanostatic Intermittent Titration Technique (GITT) is applied to a lithium iron phosphate half cell and a graphite half cell for solid phase diffusion coefficient measurement. The Electrochemical Impedance Spectroscopy(EIS) is applied to a lithium iron phosphate half cell and a graphite half cell for electrical conductivity measurement. The polarization resistance of the battery depends on the lithium ion diffusion coefficient in the anode materials. And the ohmic resistance of the battery depends on the electrical conductivity of the battery.