Porsche Backs Battery Startup South 8 to Improve EVs in Cold Weather

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All cars struggle when temperatures plummet, but electric vehicles are particularly affected due to increased power consumption by heaters and slower battery charging as the liquid electrolyte thickens. In Chicago last January, many Tesla owners learned this the hard way when their cars failed to charge during an extreme cold spell.

A startup, South 8 Technologies, aims to make cold-weather charging more reliable by using a pressurized, liquified gas electrolyte in batteries instead of a liquid one. This innovative approach also promises to reduce the cost of lithium-ion batteries by 30%.

For car manufacturers, this potential cost reduction is significant. “The battery costs about a third of the entire car,” CEO Tom Stepien explained.

South 8 asserts that its manufacturing technique can also cut down the size of some of the most expensive parts of a battery factory. By injecting pressurized gas into the cells, South 8 can prevent the electrolyte from freezing until -100 degrees C. This is well below the point at which nearly every other solvent solidifies.

“At -40 degrees C, we retain 75% of the energy capacity,” Stepien stated. “Everything else is a brick.”

Recently, Porsche Ventures invested in South 8 Technologies through a SAFE note, which will be part of a Series B round. The company, however, has not disclosed the size of Porsche’s investment.

Porsche’s main interest lies in South 8’s low-temperature performance, according to Stepien. “They want to keep their finger on the pulse of where things are headed.” Previous investors include LG, Anzu Partners, and Lockheed. The startup originated from research conducted at UC San Diego, an area that last experienced a freeze in 1963.

South 8’s core technology, branded as LiGas, is based on a gas commonly used as a refrigerant (early research suggests it’s difluoromethylene, or R-32). However, incorporating the pressurized electrolyte into the cells presents challenges. This approach currently only works with cylindrical cells, the type used in Teslas, Rivians, and Lucids. Most automakers today use prismatic or pouch cells, though Stepien mentioned they might consider adapting the technology for prismatic cells in the future because of their rigid structure, unlike pouch cells.

In cylindrical cells, South 8’s pressurized electrolyte necessitates stronger end caps. The top cap also needs to be welded on and must feature a valve for injecting the electrolyte.

This different equipment requirement may pose a challenge for adoption, given the substantial investments battery manufacturers have already made in their gigafactories. Nevertheless, Stepien hopes South 8’s technology will offer savings that are hard to ignore.

For example, South 8’s technology could speed up production by reducing the formation cycle, during which batteries are initially charged and discharged to form a protective layer on the anodes. This process usually takes days, but South 8 claims it can reduce this time by 90%.

“Our standard protocol was about 100 hours for cells we create for our customers. We’ve performed tests and observed no difference in performance with just 10 hours,” Stepien noted. Although the gas used in the cells is a potent greenhouse gas, generating over 600 times more global warming potential than an equivalent amount of CO2 (according to the IPCC), battery recyclers would need to adopt new protocols to ensure the gas does not escape, similar to handling air conditioning and refrigerator compressors but on a larger scale. If successful in developing a recycling solution and reducing the number of cells required for cold-climate EVs, South 8’s liquified gas electrolyte could ultimately benefit the climate.

Tim De Chant
Tim De Chant
Senior climate reporter. Previously, Tim has written for Wired magazine, The Wire China, the Chicago Tribune, and NOVA Next, among others, and he is also a lecturer in MIT’s Graduate Program in Science Writing. De Chant was awarded a Knight Science Journalism Fellowship at MIT in 2018, and he received his PhD in environmental science, policy, and management from the University of California, Berkeley.

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