Charging electric vehicles 5x faster in subfreezing temps

Summary

A stabilizing coating on an electrode, combined with microscale channels, helps solve the trade-off between range and charging speed, even in cold temperatures Engineering student Chloe Acosta plugs in an EV for charging in snowy weather on the University of Michigan’s North Campus. EV charging becomes less efficient in colder weather, but a new strategy for manufacturing battery electrodes could enable charging in 10 minutes in temperatures as cold as -10C. Image credit: Marcin Szczepanski, Michigan Engineering A modified manufacturing process for electric vehicle batteries, developed by University of Michigan engineers, could enable high ranges and fast charging in cold weather, solving problems that are turning potential EV buyers away. “We envision this approach as something that EV battery manufacturers could adopt without major changes to existing factories,” said Neil Dasgupta, U-M associate professor of mechanical engineering and materials science and engineering, and corresponding author of the study published in Joule. Neil Dasgupta “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.” Lithium-ion EV batteries made this way can charge 500% faster at temperatures as low as 14 F (-10 C). The structure and coating demonstrated by the team prevented the formation of performance-hindering lithium plating on the battery’s electrodes. As a result, batteries with these modifications keep 97% of their capacity even after being fast-charged 100 times at very cold temperatures. Current EV batteries store and release power through the movement of lithium ions back and forth between electrodes via a liquid electrolyte. In cold temperatures, this movement of the ions slows, reducing both battery power as well as the charging rate. To extend range, automakers have increased the thickness of the electrodes they use in battery cells. While that has ...