Electric vehicle researchers once dreamed of using flow battery technology to make a zero emission car that could range as far and wide as a gasmobile. Nobody is talking much about that any more, but the US Department of Energy has just bet $3 million on a new energy storage project that could turn the dream into reality.
The Dream Of A Flow Battery Electric Vehicle…
For those of you new to the topic, the “flow” in a flow battery is literal. The idea is to produce electricity by making two specially treated liquids flow adjacent to each other. Typically the liquids are separated by a thin membrane, though researchers have been working on advanced tech without one.
With the right tweaks, flow batteries can be inexpensive, and they can be made with raw materials that are abundant, eco-friendly, and shielded from geopolitical complications. Flow batteries are an ideal fit for the electric vehicle revolution, except that the current generation of flow battery systems tends to be relatively large and expensive, and they would have to be carted behind an electric vehicle on a trailer.
…Might Not Be A Fantasy After All.
Nevertheless, back in 2013 General Electric proposed a flow battery electric vehicle, which went something like this:
“A hydrogenated organic liquid carrier is fed to the anode of a PEM fuel cell where it is electrochemically dehydrogenated, generating electricity, while air oxygen is reduced at the cathode to water. To recharge the flow battery, the reactions are reversed and the organic liquid is electrochemically re-hydrogenated, or rapidly replaced with the hydrogenated form at a refueling station.”
The GE project was funded with support from the ARPA-E RANGE initiative for improving electric vehicle batteries, but it seems to have gone nowhere. Another flow battery project under the ARPA-E umbrella was funded around the same time and was soon cancelled.
One Step Closer To A Flow Battery Electric Vehicle
The excitement over a mashup between flow batteries and electric vehicles probably faded out in short order because lithium-ion technology has been getting less expensive and more efficient. Still, there are signs that flow batteries could find a place in the zero emission mobility world of the future.
That brings us to the latest energy storage news from Case Western University, which won that $3 million award for new flow battery technology.
To be clear, the Case Western team is not aiming at the electric vehicle market. However, they are working on shrinking the size of flow batteries down to a manageable system that could be installed in a typical home, like any other appliance.
The cost of raw materials has been one key obstacle to widespread adoption of flow batteries, but researchers at Case Western have been working with Pacific Northwest Laboratory and other partners to reduce the cost. One solution is to use a slurry based on iron.
“If successful, these “slurry electrode iron flow batteries” being developed at Case Western Reserve could someday be simple refrigerator-sized units placed at the end of a city block or even in the basement of a house to store wind- or solar-generated energy for 10 to 24 hours,” explains the university’s project leaders, professor of chemical engineering Jesse Wainright.
Why Not Lithium-Ion Batteries?
Considering all the improvements in lithium-ion technology over the years, it is fair to ask why another energy storage technology is needed. Part of the answer is that millions of electric vehicles are set to hit the road in the coming years, and almost all of them will be sporting lithium-ion batteries. Combine that with the surging interest in home energy storage as well as commercial and grid-scale energy storage, and you have a recipe for supply bottlenecks, rising costs, and environmental impacts.
On the bright side, abundant supplies of lithium could be extracted from various types of brine without the need for disruptive mining, though scaling up and commercializing that technology is going to take a while.
In an interesting twist, iron could end up playing a role in next-generation lithium-ion technology that helps get more batteries into circulation at less cost.
That could also take a while. In the meantime, rather than putting all energy storage eggs in one basket, it seems wise to diversify the supply chain.
Anyways, the US Army Corps of Engineers seems to think so. Back in 2018 they hosted a demonstration of a flow battery developed by the company Energy Storage Systems, through the support of a 2014 ARPA-E grant.
The Long Road To A Flow Battery Electric Vehicle
If you’re guessing the Army Corps was testing an electric vehicle, guess again. ESS was working on stationary flow battery system, not a rolling one. ESS popped up again on the CleanTechnica radar in 2019, when we observed that “the US Department of Defense — a big fan of clean tech — installed the company’s Energy Warehouse™ flow battery at Marine Corps Base Camp Pendleton in San Diego, where renewable energy has been a thing since 2011.”
Where were we? Oh right, last we heard, ESS cranked its energy storage technology to exceed 12 hours, so stay tuned for more on that.
If you are still dreaming of a flow battery electric vehicle, it appears the dream is still alive. Not too long ago the University of Glasgow in Scotland introduced the idea of a flow battery-hydrogen mashup that could do this:
“One potential benefit of this system is that electric cars could be charged in seconds, as the material is a pumpable liquid. This could mean that the battery of an electric car could be “recharged” in roughly the same length of time as petrol cars can be filled up. The old battery liquid would be removed at the same time and recharged ready to be used again.”
But wait, there’s more.
The research team is “convinced that this result will help pave the way for the development of new energy storage systems that could be used in electric cars, for the storage of renewable energy, and to develop electric-to-gas energy systems for when a fuel is required,” the University of Glasgow enthused.
They cite research team co-leader Professor Leroy (Lee) Cronin, who said that “our approach…could even have application in electric cars where batteries can still take hours to recharge and have limited capacity. Moreover, the very high energy density of our material could increase the range of electric cars, and also increase the resilience of energy storage systems to keep the lights on at times of peak demand.”
That was back in 2018 and much could be happening since then, so stay tuned for more on that topic.
Follow me on Twitter @TinaMCasey.
Photo: Flow battery research at Pacific Northwest National Laboratory (courtesy of PNNL).
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