Charging electric vehicles in freezing weather could soon be dramatically faster, thanks to a breakthrough from engineers at the University of Michigan that boosts lithium-ion battery charging speeds by up to 500% at temperatures as low as -10°C (14°F). The advance, which combines a new battery structure with an ultra-thin protective coating, addresses a key limitation that has long challenged EV performance in cold climates.
“Charging an EV battery takes 30 to 40 minutes even for aggressive fast charging, and that time increases to over an hour in the winter,” said Neil Dasgupta, associate professor of mechanical engineering and materials science at U-M and corresponding author of a study published in Joule. “This is the pain point we want to address.”
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Cold temperatures slow the movement of lithium ions inside batteries, reducing charging speed and battery longevity. Previous attempts to improve performance by thickening battery electrodes to increase range often backfired, making it harder for ions to reach active material. Dasgupta’s team had previously carved microscopic pathways into graphite anodes using lasers to improve ion access, but winter charging remained sluggish due to the buildup of a chemical barrier on the electrodes.
To counter this, the team developed a 20-nanometer-thick coating made from lithium borate-carbonate—a glassy material that prevents the formation of the ion-blocking layer. Combined with the microchannels, the battery retained 97% of its capacity after 100 fast-charging cycles at sub-zero temperatures.
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“For the first time, we’ve shown a pathway to simultaneously achieve extreme fast charging at low temperatures, without sacrificing the energy density of the lithium-ion battery,” Dasgupta said. He added that the technology is compatible with existing battery production lines, making it easier for manufacturers to adopt.
The innovation is being supported by the Michigan Economic Development Corporation’s MTRAC Advanced Transportation Innovation Hub. Arbor Battery Innovations has licensed the technology for commercial development. The University of Michigan and Dasgupta hold financial interests in the company.