eVTOL Design, Energy Storage & Charging

Abstract

As electric vehicles are quickly taking over the automotive industry, electric airplanes are also starting their upswing. With air travel and transport in general being a large polluter of CO2 gases, the transition to electric flight becomes more prominent every year. This transition is starting small with non-commercial airplanes. Several companies are starting with development of eVTOLs, electric Vertical Take-Off and Landing vehicles. The idea behind them is that they can easily move into and out of the city through the air, speeding up transport and travel in urban areas while keeping CO2 emissions at the vehicle level at zero.
This thesis, together with two other theses, will elaborate on the design of such an eVTOL. Its design is created by looking at the layout of the propellers, the wings and the fuselage and the internal layout is composed by working out the electric drivetrain from the energy storage to the electric motors and by drafting up the control systems. In specific, this thesis dives into the external design and the internal electric energy storage. It does this by settling on a design and calculating certain specifications, like wing area and propeller and fuselage size. From there the necessary powers and energies are calculated. With these powers and energies, a battery pack is designed together with a battery management system and a charging system. The other two theses will design the propulsion system and the control system of the eVTOL.
The result of the thesis is a theoretical design that states the possibilities of Lithium-Sulfur cells inside an eVTOL. An efficient tandem wing design with fixed wings and fixed rotors makes sure there is a healthy balance between the maximum power and total energy needed to take off vertically and fly 125 kilometers. With the Lithium-Sulfur cells a battery pack is made with its accompanying battery management system that monitors and manages the cells' characteristics. Next to the battery pack, theory on charging and a simplified charging simulation has been done to show that charging in 15 minutes should be possible by the time the eVTOL enters into service.