Purdue University engineers have devised what they describe as a refillable technology that they project could provide enough energy to run a car for about 3,000 miles. This novel type of flow battery is being successfully tested in golf carts. The technology was first showcased in 2017. The team has made significant improvements in the technology since then.
"The jump that this technology has made in the past two years is a testament to its value in changing the way we power our vehicles," said John Cushman, Purdue University distinguished professor of earth, atmospheric and planetary sciences and a professor of mathematics. "It's a game-changer for the next generation of electric cars 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."
In the image above (courtesy of Lyna Landis, Purdue Research Foundation), Eric Nauman, professor in mechanical engineering, biomedical engineering, and in basic medical sciences and co-founder of IFBattery, and Michael Dziekan, senior engineer for IFBattery, run tests on a membrane-free, flow battery being used to power a golf cart.
According to the engineers, the patented technology is safe and affordable for recharging electric and hybrid vehicle batteries. They estimate that recharging would only require replacing the fluid in the batteries about every 300 miles through a process similar to refueling a car at a gas station.
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They estimate that about every 3,000 miles, the anode material would have to be replaced. The engineers point out that this anode replacement (which they have already performed in golf carts) takes less time than is needed to do an oil change and is expected to costs about the same at approximately $65.
Unlike the fuel in conventional gas vehicles, the spent battery fluids or electrolytes can be collected and then can be recharged at a solar farm, wind turbine installation, or hydroelectric plant.
Since the first debut of the technology in 2017, Cushman and Eric Nauman, a professor in mechanical engineering, biomedical engineering, and in basic medical sciences, co-founded IFBattery Inc. to commercialize it.
"The battery does two things: it produces electricity and it produces hydrogen. That is important because most hydrogen-powered cars run on a 5,000 or 10,000 PSI tank, which can be dangerous," said Michael Dziekan, senior engineer for IFBattery. "This system generates hydrogen as you need it, so you can safely store hydrogen at pressures of 20 or 30 PSI instead of 10,000."
They first tested the flow battery technology on scooters and then larger off-road vehicles. Cushman says the next step will be testing it with industrial equipment before they move onto testing in automobiles.
"Historically, flow batteries have not been competitive because of the low energy density," Cushman said. "For example, conventional flow batteries have an energy density of about 20 Watt-hours per kilogram. A lithium-ion battery runs on 250 Watt-hours per kilogram. Our flow battery has the potential to run between three and five times that amount."
Cushman is scheduled to present the technology at the 11th annual meeting of InterPore in Valencia Spain, in May 2019. He previously presented the technology at the International Society for Porous Media 9th International Conference in Rotterdam, Netherlands and at its 10th International Conference in New Orleans.
"Conventional electric cars like Tesla have lithium-ion batteries that are usually plugged in overnight. Our flow battery uses a water-based single fluid that can run the car like it is a gas engine except it is not burning anything - it's like a hybrid of a battery and a gas," Nauman said.
Without a membrane or separator, the single-fluid technology oxidizes the anode to produce electrons, and via a reduction at the cathode, it creates an electrical current to power vehicles. The oxidant is a macro-molecule that resides in the electrolyte, but it is reduced only at the cathode.
"We are at the point now where we can generate a lot of power. More power than you would ever guess could come out of a battery like this," Cushman said.
IFBattery licensed a portion of the technology through the Purdue Research Foundation Office of Technology Commercialization and has developed patents of its own.
"It is the full circle of energy with very little waste," Cushman said. "IFBattery's components are safe enough to be stored in a family home, are stable enough to meet major production and distribution requirements and are cost-effective."
