Various aspects play into the topic of interoperability. On the one hand, there are various international charging standards, such as GB/T standard in China, CHAdeMO in Japan or the CCS2 guideline (Combined Charging System in the European variant Combo-2) in Europe, and on the other hand, there is a very wide range of hardware and software solutions of the existing charging stations and electric vehicles in the field. Interoperability is about ensuring that, as far as possible, all electric vehicles can communicate with all charging stations, because only then a vehicle owner is also able to use all e-charging stations to charge his vehicle.