(CN) — Flying cars have long been a staple of science fiction but researchers announced Monday that they are exploring how to make them real by building a better battery.
“I think flying cars have the potential to eliminate a lot of time and increase productivity and open the sky corridors to transportation,” said Chao-Yang Wang, director of the Electrochemical Engine Center at Penn State, in a statement. “But electric vertical takeoff and landing vehicles are very challenging technology for the batteries.”
The Penn State research team is examining what battery technology is needed to successfully power electric vertical takeoff and landing (eVTOL) vehicles. Their study was published Monday in the journal Joule.
“Batteries for flying cars need very high energy density so that you can stay in the air,” Wang said. “And they also need very high power during take-off and landing. It requires a lot of power to go vertically up and down.”
Wang added that it’s important the batteries can be recharged quickly, as they will tend to drain rapidly.
“Commercially, I would expect these vehicles to make 15 trips, twice a day during rush hour to justify the cost of the vehicles,” Wang said. “The first use will probably be from a city to an airport carrying three to four people about 50 miles.”
The researchers said the weight of the batteries is another factor to consider as the flying vehicles will have to be able to lift and carry them. Wang said an eVTOL would potentially have an average speed of 100 miles per hour for short trips and average 200 miles per hour for longer rides.
The team of engineers ran tests on two energy-dense lithium-ion batteries that can make a 50-mile trip after charging in just five to 10 minutes and lasting more than 2,000 fast-charges.
“The key is to heat the battery to allow rapid charging without the formation of lithium spikes that damage the battery and are dangerous. It turns out that heating the battery also allows rapid discharge of the energy held in the battery to allow for take offs and landings,” the researchers said in a statement.
The team said creating batteries specifically for flying cars is difficult as they always have to retain some sort of charge in order to remain safely in the air and to land again.
“Under normal circumstances, the three attributes necessary for an eVTOL battery work against each other,” Wang said. “High energy density reduces fast charging and fast charging usually reduces the number of possible recharge cycles. But we are able to do all three in a single battery.”