Patent ID: 8265891

Claim:
A method for determining an amount of energy actually available in an energy storage module having a plurality of individual storage cells connected in series, the method comprising the acts of: determining dynamically, by a control unit operatively coupled with the energy storage module, an upper and a lower limit voltage for the energy storage module, wherein the following acts occur; (a) during a charging operation of the energy storage module, upon reaching a maximally permissible upper cell voltage on at least one storage cell, the upper limit voltage of the energy storage module is determined by summing all cell voltages existing at that point-in-time for all of the plurality of individual storage cells; and (b) during a discharging operation of the energy storage module, upon reaching a minimally permissible lower cell voltage on at least one storage cell, the lower limit voltage of the energy module is determined by summing all cell voltages existing at that point-in-time for all of the plurality of individual storage cells; determining, by the control unit, the amount of energy actually available in the energy storage module as a function of a determined actual storage capacity and the upper limit voltage and the lower limit voltage of the energy storage module.