Method for operating a battery system , which comprises a plurality of parallel connected strings , each having at least one battery module , in which a plurality of battery cells are connected in a series circuit and/or in a parallel circuit, wherein the strings can be switched on and off from one another, and wherein individual battery cells and/or individual battery cell packs , each comprising a plurality of battery cells connected in parallel, can be switched on and off from one another and can be bypassed, comprising at least the following method steps: - detecting a fault in a battery cell ; - switching off and bypassing the faulty battery cell and/or the faulty battery cell pack in which the faulty battery cell is located; - switching off the faulty string which has the faulty battery cell and/or the faulty battery cell packet ; - comparing the string voltage of the faulty string with the string voltage of the respective intact strings in which no faults have been detected; - discharging the intact strings if voltage differences between the intact strings exceed a voltage threshold value, - switching on the faulty string , if the string voltages of the respective intact strings have almost matched the level of the string voltage of the faulty string , or if a recuperation process takes place during the discharging of the intact strings . the strings can be switched on and off from one another, and wherein individual battery cells and/or individual battery cell packs , each comprising a plurality of battery cells connected in parallel, can be switched on and off from one another and can be bypassed, comprising at least the following method steps: - detecting a fault in a battery cell ; - switching off and bypassing the faulty battery cell and/or the faulty battery cell pack in which the faulty battery cell is located; - switching off the faulty string which has the faulty battery cell and/or the faulty battery cell packet ; - comparing the string voltage of the faulty string with the string voltage of the respective intact strings in which no faults have been detected; - discharging the intact strings if voltage differences between the intact strings exceed a voltage threshold value, - switching on the faulty string , if the string voltages of the respective intact strings have almost matched the level of the string voltage of the faulty string , or if a recuperation process takes place during the discharging of the intact strings . - detecting a fault in a battery cell ; - switching off and bypassing the faulty battery cell and/or the faulty battery cell pack in which the faulty battery cell is located; - switching off the faulty string which has the faulty battery cell and/or the faulty battery cell packet ; - comparing the string voltage of the faulty string with the string voltage of the respective intact strings in which no faults have been detected; - discharging the intact strings if voltage differences between the intact strings exceed a voltage threshold value, - switching on the faulty string , if the string voltages of the respective intact strings have almost matched the level of the string voltage of the faulty string , or if a recuperation process takes place during the discharging of the intact strings . <EOS>