1. A machine implemented method for estimating the solid phase potentials of the electrodes of a battery, the machine implemented method comprising: providing battery voltage information and an estimated solid phase potential to a model coefficient updater; updating a model coefficient by utilizing the battery voltage information and estimated solid phase potential; providing battery current information to a battery internal variable estimator; providing the updated model coefficient to the battery internal variable estimator; and estimating the solid phase potentials by utilizing the updated model coefficient and the battery current information, wherein the method is implemented on a processing device.