obtaining a measured voltage of a battery from a sensor connected to the battery;

obtaining an estimated voltage of the battery from an electrochemical model stored in a memory;

selectively applying a correction with respect to the electrochemical model between ON and OFF states respectively corresponding to performance and non-performance of the applying of the correction;

estimating an aging variation of the battery based on the measured voltage and the estimated voltage; and

updating an aging parameter of the electrochemical model using the estimated aging variation,

wherein the estimating of the age variation is performed during the OFF state.