EV charging technique promises 200 miles in 10 minutes

When Li-ion batteries are rapidly charged at ambient temperatures, lithium tends to deposit in spears on the carbon anodes. As well as potentially causing dangerous electrical spikes, this lithium plating also reduces cell capacity.

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Known as asymmetric temperature modulation (ATM), the new technique charges cells at an elevated temperature of 60ۢ°C, which eliminates the lithium plating. The self-heating battery uses a thin nickel foil with one end attached to the negative terminal and the other extending outside the cell to create a third terminal. A temperature sensor regulates the flow of electrons through the nickel foil to complete the circuit. This rapidly heats up the nickel foil through resistance heating and warms the inside of the battery. Cycles are limited to 10 minutes to prevent materials degradation, but this is enough time to add more than 200 miles range for most EVs.

"We demonstrated that we can charge an electrical vehicle in ten minutes for a 200 to 300 mile range," said research lead Chao-Yang Wang, director of the Electrochemical Engine Center at Penn State University, where the research took place.

"And we can do this maintaining 2,500 charging cycles, or the equivalent of half a million miles of travel."

Published in the journal Joule, the research showed that a high-energy (209 Wh/kg) Li-ion cell retained 91.7 per cent capacity after 2,500 rapid charging cycles using the ATM method. This is equivalent to about 500,000 miles of driving and far exceeds the US Department of Energy’s rapid charging target of 500 cycles at 20 per cent loss. According to the researchers, the breakthrough could help speed up EV adoption, as charging times are seen as a major barrier for the technology.

"The 10-minute trend is for the future and is essential for adoption of electric vehicles because it solves the range anxiety problem," said Wang.