A major step forward in high-power electric vehicle charging has been achieved through the “HV-MELA-BAT” project, led by Fraunhofer Institute for Solar Energy Systems ISE. The initiative focuses on developing next-generation megawatt charging systems to support both heavy-duty and passenger transport, addressing a critical bottleneck in the transition to electrified mobility.
The project successfully demonstrated an advanced Megawatt Charging System (MCS), capable of delivering over 1 MW of charging power. Central to this achievement is an ultra-compact, galvanically isolated DC/DC converter with a capacity of 250 kW. By connecting four such modules in parallel, the system reaches megawatt-scale output. Notably, the converter achieves a record efficiency of 99.26 percent and a volumetric power density of 9 kW per liter, enabled by high switching frequencies of up to 200 kHz and innovative resonant circuit design.
To address grid limitations, the system integrates a buffer storage unit using second-life EV batteries. This allows the charging station to operate with a grid connection of just 500 kW, while the remaining power demand is met by the storage system during peak loads. This approach not only reduces strain on the grid but also enhances flexibility and scalability.
The HV-MELA-BAT system is designed to be compatible with the existing Combined Charging System (CCS), ensuring a smooth transition to the newer MCS standard. It also supports integration with renewable energy sources such as solar power, which can either directly charge vehicles or be stored for later use.
Project partners include Mercedes-Benz Energy GmbH and Fraunhofer IVI, among others. The system was tested at Fraunhofer ISE’s facilities in Freiburg, demonstrating high efficiency and adaptability across various charging scenarios.
Backed by Germany’s Federal Ministry for Economic Affairs and Energy, the project marks a significant milestone in enabling fast, efficient, and scalable charging infrastructure for the future of electric transport.
