Face contact technology for a megawatt charging system

The transmission of high electrical power via separable contact connections represents a key challenge in the context of the energy transition and electromobility. A well-known example is the charging interface of battery electric vehicles (BEV). To overcome current limitations in charging capacity, three institutes of the Fraunhofer-Gesellschaft IVI, IST and IWU are developing an innovative megawatt charging interface that uses face contacts with a normal force up to 100 N instead of conventional sliding contacts. The benefits are a robust electrical connection with a maximized contact area as the basis for the lowest possible contact resistance and thermal losses. The publication provides a comprehensive overview of the research work, starting with the system concept, based on the relevant standards and the specifications derived from them. Following, several simulation tools were combined to design the overall system and the electrical active point. These are explained in their interaction and limit the extent of experimental work for the technical realization. The further development of production technology is focused on the surface design of the face contacts, regarding a specifically designed texture and coating system for low-wear and low-resistance contact points. Furthermore, a thin-film temperature sensor system was developed, positioned close to the electrical active point, to enable a highly accurate and fast responsive temperature monitoring. The individual components developed in parallel will be combined in an innovative semi-automatic megawatt charging demonstrator. The megawatt charging demonstrator described in the outlook will synthesize the technical progress of the project and will be evaluated promptly.