LiBAT: A High-Performance AC Battery System for Transport Applications

The paper proposes a novel battery design for high-performance transport applications that is immersion-cooled and switched by a multi-level inverter. Advantages of the proposed AC battery design in terms of weight, modularity, scalability, performance, reliability and safety are presented. To demonstrate the applicability of the design, an electrically powered glider use case is addressed. The derived battery system is evaluated by means of theoretical analysis, simulation and prototyping. Simulations showed that the used multi-level inverter (MLI) power electronics modules could successfully run the motor without additional power electronics and charge batteries from a 110 V AC source. The prototype implementation with a motor-driven propeller demonstrated power levels of up to 3.3 kW, with a behavior in accordance with simulations. Guidelines to further advance the technology readiness level including control strategies and hardware design were derived to overcome limitations in the prototype realization that could not be addressed within the project budget. Finally, research topics to evaluate additional performance metrics such as efficiency and aging behavior are suggested.