A View from Kevin Bullis
Flow Batteries For Fast Electric Car Charging
New batteries could make recharging EVs much faster.
Electric vehicles can take hours to recharge, making cross-country road trips a challenge. But researchers at the Fraunhofer Institute for Chemical Technology in Germany say they’ve got a potential solution: flow batteries.
This type of battery uses two electrolytes rather than the solid electrodes used in lithium ion batteries. Recharging them is as fast as pumping out depleted electrolytes and replacing them with fresh ones–it wouldn’t take longer than refilling a gas tank. One of the problems with flow batteries, though, has been that they only store about a quarter of the energy as lithium ion batteries–you’d have to recharge a lot, making them impractical. The Fraunhofer researchers say they’ve improved the energy storage to match lithium ion batteries–still not as good as with gasoline, but a great improvement. Some lithium ion EVs get over 200 miles on a charge.
But here’s the catch: one of the reasons hydrogen fuel cell vehicles have come under fire recently is that you need to install a large infrastructure for distributing and dispensing hydrogen. A flow battery system would have a similar problem. You’d need to install special refueling stations where the spend electrolytes can be recharged and dispensed.