Comparison of the electron density profiles obtained by Irkutsk incoherent scatter radar with the IRI-2001

A method for operating a battery system in a vehicle that includes multiple battery units is described. The method includes classifying an instantaneous aging state of the battery units, first association of the battery units with instantaneous aging classes as a function of their instantaneous aging state, predicting a future aging state of the battery units for a future point in time, second association of the battery units with future aging classes as a function of their future aging state, ascertaining an optimal point in time for replacing battery units based on a cost function, taking into account the instantaneous aging classes and the future aging classes. A battery management system that is configured for carrying out the method is also described.