Patent ID: 7373264

Claim:
A method for determining a state of charge (SOC) or state of health (SOH) of a battery system, comprising: performing a first step including determining a set of initial values for a plurality of parameters, coefficients, and derivatives based upon a plurality of linear functional relationships, and computing a result based upon said determining; after execution of said first step, calculating a plurality of intermediate functions based on said result; updating said plurality of parameters based on said plurality of intermediate functions; determining an open circuit voltage V OC that possesses a functional relationship with a voltage-based SOC (SOC V ) based on said updated plurality of parameters; extracting said SOC V by inverting an expression of V O (SOC V ); calculating a current based SOC (SOC C ); calculating a weight for weighting said SOC C and said SOC V ; and calculating a SOC based on said weight, where V O is a battery voltage.