Apr 1, 2025 11:08 PM
https://www.eurekalert.org/news-releases/1079001
INTRO: 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.
"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 allowed them to promise longer drives between charges, it makes some of the lithium hard to access, resulting in slower charging and less power for a given battery weight.
Previously, Dasgupta's team improved battery charging capability by creating pathways—roughly 40 microns in size—in the anode, the electrode that receives lithium ions during charging. Drilling through the graphite by blasting it with lasers enabled the lithium ions to find places to lodge faster, even deep within the electrode, ensuring more uniform charging.
This sped up room-temperature charging significantly, but cold charging was still inefficient. The team identified the problem: the chemical layer that forms on the surface of the electrode from reacting with the electrolyte. Dasgupta compares this behavior to butter: you can get a knife through it whether it's warm or cold, but it's a lot harder when it's cold. If you try to fast charge through that layer, lithium metal will build up on the anode like a traffic jam.
"That plating prevents the entire electrode from being charged, once again reducing the battery's energy capacity," Manoj Jangid, U-M senior research fellow in mechanical engineering, and co-author of the study... (MORE - details, no ads)
INTRO: 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.
"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 allowed them to promise longer drives between charges, it makes some of the lithium hard to access, resulting in slower charging and less power for a given battery weight.
Previously, Dasgupta's team improved battery charging capability by creating pathways—roughly 40 microns in size—in the anode, the electrode that receives lithium ions during charging. Drilling through the graphite by blasting it with lasers enabled the lithium ions to find places to lodge faster, even deep within the electrode, ensuring more uniform charging.
This sped up room-temperature charging significantly, but cold charging was still inefficient. The team identified the problem: the chemical layer that forms on the surface of the electrode from reacting with the electrolyte. Dasgupta compares this behavior to butter: you can get a knife through it whether it's warm or cold, but it's a lot harder when it's cold. If you try to fast charge through that layer, lithium metal will build up on the anode like a traffic jam.
"That plating prevents the entire electrode from being charged, once again reducing the battery's energy capacity," Manoj Jangid, U-M senior research fellow in mechanical engineering, and co-author of the study... (MORE - details, no ads)