Image: Fraunhofer IZM | Volker MaiThe 45 participants in the EU-funded HiPower 5.0 project are convinced that electric vehicles still hold untapped potential in their integrated charging systems. The Fraunhofer Institute for Reliability and Microintegration IZM plays a central role in the HiPower 5 project, addressing the problem that current models are increasingly reaching their limits in terms of efficiency, size, and reliability. The Fraunhofer IZM demonstrated in 2024 that a compact onboard charger is feasible. Now, efficiency, costs, and size are set to be further optimised using bidirectional gallium nitride (GaN) semiconductors.The onboard charger (OBC) of an electric vehicle converts grid power into energy suitable for the battery. However, as charging power increases, so do the demands on efficiency, cooling, and space. “Conventional silicon-based technology leaves only little room for further optimisation. Energy losses mean more heat, which in turn means more need for cooling. More cooling requires larger systems, meaning the most powerful OBCs are not suitable for all vehicle sizes,” explain the Fraunhofer experts.Above all, a simpler design with fewer components is expected to improve efficiency, reduce costs, and enhance adoption. For this reason, the HiPower 5.0 consortium is working on the automotive project strand, led by Fraunhofer IZM, to develop a high-performance 22 kW OBC with a volume of just four litres—significantly smaller than current models that are typically twelve litres.The key to this size reduction lies in novel gallium nitride (GaN) semiconductors from Infineon. “These monolithically integrated, bidirectional GaN switches enable more efficient conversion in a smaller package since they are designed to control the flow of electricity in both directions,” explain the project leaders. This means a single component can perform the function of two previously interconnected semiconductors. “This opens up new technical possibilities and allows for circuit designs that would only be feasible with conventional components through compromises.”The decisive factor is not just the material itself but also how all components work together in the vehicle. Here, Fraunhofer IZM’s expertise in packaging and system development comes into play. The Fraunhofer team explains that components are not optimised individually but are considered as a complete system from the outset. Electronic components are partially integrated directly into printed circuit boards (embedding), which shortens pathways, reduces losses, and saves space.An initial demonstrator was the aforementioned compact 22 kW charging system for electric vehicles, which Fraunhofer IZM presented at PCIM Europe in 2024. This system did not yet incorporate bidirectional GaN elements. In the automotive sub-project, both approaches are now set to be combined.In total, 45 partners from ten European countries are working on six use cases within the HiPower 5.0 project, including two OEMs, 21 Tier-1/2 manufacturers, six power electronics companies, ten universities, and seven research institutions. A list of the individual participants can be found in the linked source below. The common thread across all use cases is that the advantages of modern GaN and other wide-bandgap semiconductors are to be harnessed in a fully European value chain to create market-ready products. In addition to the automotive sector, applications in shipping are also being explored.The project runs from August 2025 to June 2028 and is funded by the EU and its member states with 33.7 million euros. The German Federal Ministry of Education and Research is contributing 5.74 million euros, while the German state of Saxony is providing 120,000 euros.izm.fraunhofer.de, hipower50.eu