According to scientists at Purdue University, the best way to charge electric car batteries may be to take them to a gas station, and have them serviced at an instant oil-change shop.
The two scientists have been testing a new type of flow battery in golf carts, and say the battery now develops enough energy density and power to be viable in a car.
“It’s a game-changer for the next generation of electric cars," says John Cushman, a professor of math, and earth, atmospheric and planetary sciences at Purdue, in a university publication, "because it does not require a very costly rebuild of the electric grid throughout the US. Instead, one could convert gas stations to pump fresh electrolyte and discard depleted electrolyte and convert oil-changing facilities to anode replacing stations. It is easier and safer to use and is more environmentally friendly than existing battery systems.”
He says that the electrolyte would need to be replaced about every 300 miles (not unlike gasoline in a tank), and the anode material would have to be replaced about every 3,000 miles (similar to old-fashioned oil changes).
Purdue calls it the "instantly rechargeable" battery. It uses a water, ethanol, and salts and either an aluminum or zinc anode. The electrical charge in the liquid cathode-electrolyte are depleted with use (as in any flow battery). "One of the big weaknesses of most batteries is the breakdown of the membrane. We don't have a membrane," Cushman says.
The chemical reaction produces electricity and hydrogen. The hydrogen is then collected in low-pressure tanks and fed into a small fuel cell to make additional electricity for the motor.
If a gas station were converted to add electrolyte to the battery, a driver could pull in, and the station would remove the old electrolyte and add new. The old electrolyte could then be collected and recharged at a central station using any form of electricity, including from renewable energy sources.
Cushman says it can store up to 1,300 watt-hours per kilogram, or about three to five times the amount of a state-of-the-art lithium-ion battery.
He founded a company IFBattery ("if-battery") with fellow professor Eric Nauman (Purdue professor of mechanical engineering and biomedical engineering) to commercialize the batteries.
Next, Cushman hopes to move beyond golf carts and scooters and test it in industrial equipment, and eventually cars.
By then, this new flow battery could face some stiff competition from new solid-state lithium batteries in conjunction with more widespread charging infrastructure, but Cushman hopes his battery will offer compelling cost savings.