Method for determining a state of charge of an electric energy store, electric energy store, and device

The invention relates to a method for determining the state of charge of an electric energy store comprising electric energy store cells and a sensor, in which method: in a first method step, operating parameters of the electric energy store are determined; in a second method step, a maximum state of charge and a minimum state of charge are determined as a temporal integral for each electric energy store cell on the basis of a current (I), a current measuring inaccuracy (ΔI), a capacity, a correction value for the minimum state of charge, and a correction value for the maximum state of charge of the electric energy store cells; the correction value for the minimum state of charge is determined by means of a minimum state of charge on the basis of a filtered minimum open-circuit voltage of the electric energy store; the correction value for the maximum state of charge is determined by means of a maximum state of charge on the basis of a filtered maximum open-circuit voltage of the electric energy store; wherein a maximum state of charge (SOC) of the electric energy store is the maximum of the maximum states of charge of all the electric energy store cells, and a minimum state of charge (SOC) of the electric energy store is the minimum of the minimum states of charge of all the electric energy store cells.