Non-flammable lithium battery startup attracts funding
Balsara, who has been working for many years trying to find a way to improve the safety of lithium-ion batteries, set up Blue Current together with co-inventor, Joseph DeSimone of the University of North Carolina at Chapel Hill.
The non-flammable electrolyte Blue Current is developing features a fluorinated liquid called perfluoropolyether, or PFPE. “Things that contain fluorine don’t burn very easily,” explained Balsara, a researcher in the Materials Sciences and Energy Storage Divisions of Berkeley Lab and also a professor of Chemical and Biomolecular Engineering at UC Berkeley. “They’ll evaporate, but they won’t catch fire.”
“With current lithium batteries safety is engineered through the battery management system,” Balsara said. “Although they are generally considered safe, you still have an electrolyte in the battery that is flammable, and every so often something might go wrong. We want to take that anxiety out of the battery.”
Two of Blue Current’s three co-founders, Nitash Balsara (left) and Alex Teran. (Photo courtesy Blue Current)
As described in a paper published during 2014 in the Proceedings of the National Academy of Science, Balsara, DeSimone, and co-authors demonstrated that their PFPE-based electrolytes “exhibit reasonable conductivity and unprecedented transference numbers” and are compatible with standard battery electrodes. The transference number, which quantifies the relative ease with which lithium ions move in electrolytes, is an important parameter that influences battery performance.
There is no non-flammable lithium battery on the market today. Balsara himself co-founded his first battery company, Seeo, in 2007 based on another one of his inventions, a dry polymer electrolyte, which is non-flammable. Seeo recently announced a major investment from Samsung Ventures, but Balsara is no longer directly involved with the company.
Blue Current, based in Berkeley, California, employs three battery scientists and is looking to hire more. Along with Balsara and DeSimone, the third co-founder is
Alex Teran, a former graduate student of Balsara’s. The company name was chosen to reflect the safe passage of current through batteries.
The main challenge now is to improve the conductivity of their PFPE electrolyte. “Because the fluorinated compound is not as conductive, you can’t charge these
batteries very quickly, and you can’t draw current very quickly,” pointed out Balsara. “The company’s research goal is to hasten the ions’ motion through the electrolyte.”
The slow discharge performance is not ideal for some applications. For example, slow discharge would compromise acceleration performance when stepping on an electric car’s accerelerator. “If there’s a truck coming, you need to accelerate," admitted Balsara. “So while this electrolyte may not be ideal for vehicles at this point, there are other applications where the rate of discharge is not as important.”
Blue Current’s engineers are working on modifying the molecular structure of the electrolyte in order to speed up lithium ion motion. Balsara points out that there are uses where the battery does not need to respond in seconds or even minutes. For example, as more people are installing solar panels on their homes, some are thinking about storing that energy for rainy days or nighttime use. “There are applications where safety is not a luxury but a necessity,” suggested.
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