SYSTEM AND METHOD FOR ESTIMATING STATE OF CHARGE OF A LITHIUM BATTERY CELL OF A VEHICLE

A method and system for estimating state of charge of a lithium battery cell of a vehicle is provided. The method comprises providing a non-linear function of the lithium battery cell, a normalized lithium surface density and an actual voltage at a current of the lithium battery cell having an internal resistance. The method further comprises determining an actual lithium surface density based on the actual voltage relative to an inverse of the non-linear function. The method further comprises determining a varying parameter based on the actual lithium surface density relative to a first diffusion model. The method further comprises determining a predicted lithium surface density based on the varying parameter relative to a second diffusion model. The method further comprises determining an estimated state of charge of the lithium battery cell when a difference between the predicted and actual lithium surface densities is less than a first threshold.