Fast charging of battery electric vehicles (BEVs) is an essential purchase criterion. In the case of heavy-duty vehicles, it influences the commercial usage and in the case of passenger cars represents added value for the driver in real-life driving. Even if the necessary charging infrastructure is either still being developed or is at least not yet sufficiently available. This publication looks at possible energy system architectures at vehicle level and component solutions to achieve very high charging power and associated fast charging speed in km/min, where the state of the art lies and which challenges still need to be overcome. In this context, the derived requirements for the charging stations will be discussed. Furthermore, the fundamental question of whether fast charging can be efficient will be discussed and an outlook on the possible roll-out of the technology will be given.