All cars suffer when the mercury drops, but electric vehicles suffer more than most as heaters draw more power and batteries charge more slowly as the liquid electrolyte inside thickens. Drivers in Chicago found this out the hard way last January after many Teslas failed to charge during a deep freeze.
One startup, South 8 Technologies, says it can make cold-weather charging more reliable by filling batteries with a pressurized, liquified gas electrolyte instead of a liquid one. In the process, it hopes to slash the cost of lithium-ion batteries by 30%.
For automakers, if that savings pans out, it might be too good to pass up. “The battery costs about a third of the entire car,” CEO Tom Stepien told TechCrunch.
South 8 claims that its manufacturing technique can reduce the size of some of the costliest parts of a battery factory. And by injecting gas under pressure into the cell, South 8 can prevent the electrolyte from freezing until –100 degrees C, well below the point at which nearly every other solvent has turned into a solid.
“At –40 degrees C, we retain 75% of the energy capacity,” Stepien said. “Everything else is a brick.”
The company recently attracted new funding from Porsche Ventures in the form of a SAFE note, which will be applied to a Series B round that the company is starting to raise. Stepien said he could not disclose the size of Porsche’s investment.
Porsche appeared primarily interested in South 8’s low-temperature performance, Stepien said. “They want to keep their finger on the pulse of where things are headed,” he said. LG, Anzu Partners, and Lockheed are prior investors. The startup was spun out of research at UC San Diego, which is basically an EV paradise — it last froze there in 1963.
South 8’s core technology, which it calls LiGas, is based on a gas that is most commonly used as a refrigerant. (Early scientific work published by the founding team suggests it’s difluoromethylene, otherwise known as R-32.) Getting the pressurized electrolyte into the cell, though, presents a couple challenges. First, the approach only works with cylindrical cells, the sort used in Teslas, Rivians, and Lucids. Today, most automakers use prismatic or pouch cells. Stepien said that the company would consider applying the technology to prismatic cells in the future because they have a rigid can, but pouch cells do not, so they’re off the table.
In cylindrical cells, South 8’s pressurized electrolyte requires the end caps to be stronger. The top cap also has to be welded on, and it requires a new design to include a valve through which the electrolyte is injected.
All that means different equipment, which poses a hurdle to adoption given the billions that battery manufacturers have invested in their gigafactories. Still, Stepien hopes that South 8’s technology will ultimately translate into savings that are too big to ignore.
For one, Stepien said South 8’s technology will speed production time because it can reduce the formation cycle, in which batteries are first charged and discharged. The process can take days, and it helps form a layer atop the anodes that helps the battery reach its potential. Stepien said South 8 can reduce that time by 90%.
“Our standard protocol here was about 100 hours for cells we make for our customers. We’ve done tests, and we’ve seen no difference in performance with 10 hours,” Stepien said. The gas in the cells is itself a potent greenhouse gas, generating over 600 times more global warming than an equivalent amount of carbon dioxide, according to the IPCC. Should billions of cells be manufactured with the electrolyte, battery recyclers will need to add new steps to their process to ensure the gas doesn’t escape to the atmosphere. Recyclers have similar protocols for handling air conditioning and refrigerator compressors, though on a much smaller scale. Still, if South 8 can help develop a recycling solution while also reducing the number of cells needed for cold-climate EVs, their liquified gas electrolyte could be a net benefit for the climate.