Protective circuit for a battery pack

The protective circuit has predetermined number of single cells, which are successively switched in two cell rows (A,B,C,D), which lie parallel to each other. A phase current (Ia,Ib,Ic,Id) flowing while loading the battery pack in one cell row is compared with the phase current flowing in another cell row, where a signal is generated when no plausible deviation of the phase currents is found. The signal is generated when difference of the phase currentsexceed a predetermined value (IG). The non-plausible deviation is derived from a ratio of the phase currents to each other.