Engineers at the University of Michigan have created a redesigned EV battery manufacturing technique that greatly accelerates charging in cold weather. The invention solves a major issue with EV adoption: decreased efficiency at cold temperatures.
The work presents a novel approach that preserves energy density while enabling extremely quick charging at low temperatures.
Even at temperatures as low as 14 °F (-10 °C), the lithium-ion batteries that use this technique may charge 500% faster. A structural and coating change that stops lithium plating on the electrodes—a frequent problem that impairs battery performance—is the main improvement. Consequently, after 100 cycles of quick charging under subfreezing conditions, these batteries maintain 97% of their capacity.
Lithium ions are transferred between electrodes via a liquid electrolyte in conventional EV batteries to store and release electricity. This movement slows down in colder climates, though, which lowers battery efficiency and charging speed. Automakers have thickened battery electrodes to increase range, but this slows down charging.
The researchers used a thin, 20-nanometer glassy covering composed of lithium borate-carbonate to address this. Together with the laser-drilled channels, this stopped the troublesome surface layer from developing and allowed for 500% faster charging in freezing temperatures.
The study was carried out at the Michigan Center for Materials Characterization and the U-M Battery Lab. With assistance from U-M Innovation Partnerships, the group has submitted a patent application. The channel technology has been licensed by Arbor Battery Innovations, which is pursuing commercialization.
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