Energy system for a motor vehicle and method for charging an electrical energy storage device

A method for charging at least one electrical energy storage device of a motor vehicle, comprising:

• electrically subdividing a plurality of electrical cells of the energy storage device into at least two equivalent energy storage sub-devices with the same number of electrical cells for the duration of the charging process and they are connected in series, wherein the at least one energy storage device is sub-divided into the energy storage sub-devices as a function of a charging voltage available for the charging process, wherein the total of the nominal voltages of the energy storage sub-devices is less than or equal to the charging voltage.