Simulation of Electrolyte Composition Effects on High Energy Lithium-Ion Cells

Abstract

A physics-based simulation model is used to characterize the effect of different LiPF6-based electrolyte systems on discharge energy of a high energy cell design at temperatures of -25, 0, 25 and 50°C and rates of C/10, C/5, C/2, C, and 2C. At 0°C and above at discharge rates below C/5, the electrolyte has almost no effect. The electrolyte properties only become important at high discharge rates and especially at low temperatures. The conductivity and diffusivity are highly correlated, though the correlation becomes slightly weaker at low temperatures. At rates that severely reduce utilization of cell energy, the diffusivity becomes the key parameter to correlate with discharge energy, else the concentration conductivity correlates best.