We cannot naively assume that batteries designed for electric vehicles will be sufficient for flying cars and other forms of urban air transport, a new study into flying electric vehicles has recommended.
Never letting flying car batteries run fully out of charge will be a critical aspect to safe widespread air-based transport adoption, the research from Penn State University found, as the required margin of safety is even higher than in an electric vehicle.
While smartphones’ lithium-ion batteries work best when allowed to fully discharge before being recharged, flying cars require power both to stay airborne and to land.
General Motors, Airbus, Intel and Boeing are among the big names to invest in electric vertical take-off and landing (eVTOL) aircraft in recent years, which resemble giant electric-powered drones large enough to transport human passengers.
“I think flying cars have the potential to eliminate a lot of time and increase productivity and open the sky corridors to transportation,” study author Chao-Yang Wang, director of the Electrochemical Engine Centre at the University, said.
“But electric vertical takeoff and landing vehicles are very challenging technology for the batteries.”
Flying car batteries require very high energy density to stay in the air and enough power to facilitate take-off and landing, he said, pointing out that they’ll also need to be capable of recharging rapidly to make higher numbers of trips during rush hours.
“Commercially, I would expect these vehicles to make 15 trips, twice a day during rush hour to justify the cost of the vehicles,” Mr Wang added. “The first use will probably be from a city to an airport carrying three to four people about 50 miles.”
Such batteries will also need to be as light as possible to prevent hampering lift-off and landing and are likely to last more than 2,000 fast-charges over the course of their lifetime.
“I hope that the work we have done in this paper will give people a solid idea that we don’t need another 20 years to finally get these vehicles,” Mr Wang said. “I believe we have demonstrated that the eVTOL is commercially viable.”