The European “Green Deal” initiative by the EU commission strives for sustainable mobility and efficient use of resources. Within HiEFFICIENT the project partners will work towards these goals and will develop the next generation of wide band-gap semiconductors (WBG) in the area of smart mobility. To boost this development and the market introduction in automotive applications, HiEFFICIENT partners have set ambitious goals to gain higher acceptance and achieve the maximum benefit in using WBG semiconductors: 1.) Reduction in Volume of 40%, by means of integration on all levels (component-, subsystem- and system level), 2.) Increase efficiency beyond 98%, while reducing losses of up to 50%, 3.) Increase reliability of wide band-gap power electronic system to ensure a lifetime improvement of up to 20%. To accomplish the targeted goals, the partners will work on industrial use cases to demonstrate the key achievements and the progress that goes beyond state of the art. This includes, amongst others, modular inverters with different voltage levels (such as 48V, 400V, 800V), flexible on- and multi-use off-board chargers for different voltage levels, multi-purpose DC/DC converters and test systems for power electronics’ lifetime testing. These use cases are led by OEMs and other industrial partners, who define requirements and specifications for the envisioned systems. The project work starts at component-level, developing highly integrated GaN and SiC devices, and is followed by multi-objective design optimization and virtual prototyping approaches. High integration means big challenges in thermal management, which will be addressed by the development of advanced cooling concepts and modularity for the sake of maintainability and flexibility for future applications. Finally, the demonstrators are integrated in relevant environments to proof the concepts and the applicability for electric drivetrains with higher integration, higher efficiency, and higher reliability.