Filling up an electric car battery like a gas engine


Check out this idea: a next-generation electric car where you could refuel the battery’s electrolyte in the same way you’d fill up an internal combustion car at the gas station. Sound crazy? Well, a startup called Eos Energy Storage is researching a next-generation hybrid flow battery made from zinc and air that could provide such a scenario.

The refillable flow electric car battery isn’t the company’s first target product — that would be a low cost zinc air grid battery — but it’s the firm’s most unusual. Eos Energy Storage President Steve Hellman explained to me how the hybrid flow battery works in an interview at the ARPA-E event on Monday, and said the application is possible because the company uses air for its cathode, zinc as its anode and a liquid electrolyte.

A battery is made up of an anode on one side and a cathode on the other, with an electrolyte in between. For a zinc battery, zinc ions travel from the anode to the cathode through the electrolyte, creating a chemical reaction that allows electrons to be harvested along the way. Eos could create a system that could plug into one of its used flow batteries and pump out the used electrolyte, with the zinc dissolved in it, and pump in new electrolyte with new zinc to created a newly charged battery. Envision pulling into a gas station and taking a few minute to fill ‘er up with electrolyte.

O.K., the idea is still in the very earliest stages of research and development and concept. And technologies that try to build entirely new infrastructures tend to struggle with capital costs (where are all the natural gas cars or refuelable fuel cell powered laptops?). But Eos says an electric car that utilizes its flow technology could theoretically cost $25,000, have a range of 400-miles and take 3 minutes to charge.

Eos Energy won’t even be commercializing its first product, the grid battery, until late 2013, or early 2014. That initial product could potentially be a game changer for the power grid, providing low cost, long lasting energy storage, and delivering a battery cell that costs $160 per kWh, lasts 30 years and is made up of everyday benign materials.

Scientists have been working on using air (and water) as the cathode for batteries for half a century. But Eos Energy’s founder and inventor Steven Amendola discovered a breakthrough with his original design of the bi-directional air cathode that could last for 10,000 cycles (or around three decades). The company has largely been funded by its management team, but is in the process of closing a funding round from strategic investors for scaling up its first grid zinc air battery.

Image courtesy of Raindog.



Well I believe that EOS has a far better approach than Better Place. But the main problem that both technologies have is getting car manufactures to agree on standardized technology of the most important part of an electric car it’s battery.

But if by chance the automakers and business industry in general decides to have a kumbayah moment and agree to a standardized battery technology without government regulation let’s look at the cost and benefits of both technologies. A Better Place requires an attendant to swap the battery out an added cost to this technology. On the other hand the EOS is self serve just like filling up your gas tank now at a service station.

You also have the issue with the amount of times that battery which is based on regular lithium ion battery’s can be charged without having to be replaced and then an agreement with all stations to swap out each other’s batteries.

EOS tech is reported to last 30 years and requires no battery swap out plus you have the added benefit that companies that supply electric crude could compete on the quality of their recipe of the electric crude much like today’s gas stations.

But again it’s all a pipe dream because no car manufacture is gonna give up their most competitive edge in the electric car market now which is range by agreeing to standardized the electric car battery’s.

Plus the speed at which battery technology is moving we shouldn’t limit ourselves at the moment with standardized batteries because the weight of the battery is a big problem on electric car range the density of Kwh per gram becomes very important new technologies just increased that by 2.5 times think about how limiting that would be if we standardized the current technologies.

Unfortunately it’s too early to even push for a standardized battery technology so I can’t see either technology take off at the moment and if they are pushed might damage the future of electric cars in general.


Katie, that’s an interesting idea. But it sounds a bit too complicated (prone to bugs). There is a simpler but similar solution that has already been implemented in Israel and may expand to other countries soon. A company called Better Place has decided to “revolutionize” through business model innovation rather than technological innovation — i.e., make electric batteries standard so an empty battery can be swapped for a charged one at a battery switching station, and make customers pay for miles driven rather than making them pre-pay for the (very expensive) battery. Thus, consumers get 2 big benefits: 1) ease and speed of recharging


I have been following the company, Better Place and find their solution better. The model follows the idea that the battery is a commodity fuel source, not a proprietary technology. However, Tesla, I believe is using the battery not only as a fuel technology, but also part of the cars structural component. I prefer Better Place’s approach, however it would be great to figure out how to implement Tesla’s engineering of using the battery as part of the cars structural support.


Good point! I wasn’t aware of Tesla’s special design. It makes sense especially for a sports car that aims at aesthetics and speed. But if Better Place succeeds in rolling its plan on a large scale, I’m sure the company’s engineers will have more resources and confidence to start tackling the Tesla conundrum, as well. Only time will tell, I guess.

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