Technique for operating a traction energy storage system

One technique for operating a traction energy storage system (100) of a vehicle having a plurality of parallel switching power storing (102) will be described. With regard to a method aspect of the art is primarily a subset (112) of the energy store connected in parallel. At least one hinzuzuschaltender energy storage is not connected in parallel with the parallel-connected subset. An inner resistor (116) of the parallel-connected subset (112) of the energy store, an open circuit voltage (114) of the parallel-connected subset (112) of the energy storage and an open circuit voltage of at least one hinzuzuschaltenden energy store is determined. A current (128) through the parallel-connected subset (112) of the energy store is controlled so that the open circuit voltage (114) of the parallel-connected subset (112) of the energy storage and through the stream (128) and the internal resistance bewirkter (116) voltage drop a voltage (124) the parallel-connected subset (112) of the energy storage shown by the open-circuit voltage (302) of an energy storage hinzuzuschaltenden by less than a predetermined switching voltage deviates at least. Meanwhile, the at least one energy storage hinzuzuschaltende with the parallel-connected subset (112) of the energy store is connected in parallel.