A battery system (10) has a battery (12) for providing a first voltage and has at least one tap (15, 19, 21) that divides the battery (12) into at least one first battery element (14) for providing a first partial voltage and at least one second battery element (16) for providing a second partial voltage. A power changeover switch (18) is arranged between the at least one first battery element (14) and the at least one second battery element (16) and is designed to change over between the at least one first battery element (14) and the at least one second battery element (16) at a changeover rate to be specified.