UNIVERSITY PARK, Pa. — Revolutionizing the way electric vehicle batteries charge and spurring the technology as an environmental and economic growth driver will be possible thanks to a $1 million grant from the U.S. Department of Energy to Penn State engineers.
"We are going to utilize a very novel strategy," said Chao-Yang Wang, professor of mechanical, chemical and materials science and engineering, and the William E. Diefenderfer Chair Professor.
With Xiao-Guang Yang, assistant research professor of mechanical engineering, and Donghai Wang, professor of mechanical engineering, Chao-Yang Wang is developing a new lithium-ion battery that enables faster charging.
"We're going to have the battery operate at a higher temperature, around that of a human's body," he explained.
In a battery, ions flows from the cathode to the anode, resulting in a positive energy charge for the unit.
"But how fast it charges the battery is really limited by the speed the ions can move," Chao-Yang Wang said. "We found that if you increase the temperature, those ions will swim faster. That's the whole concept behind our approach.
"If you hook up your car to one of the fast chargers currently available, the new battery will induce self-heating to bring up the battery temperature quickly, even in cold environments," he explained.
This advancement could prove crucial for the widespread adoption of electric vehicles. Currently, their batteries are highly affected by outside temperatures. In optimal conditions, it would take roughly half an hour to obtain a charge to drive about 200 miles. However, in extremely cold climates, charging times could extend to three to four hours by the slow speed of ion transfer.
"That's miserable!" Chao-Yang Wang said.
In those conditions, the charger would intentionally slow down the ion flow.
"Because if it's too cold, the battery can't take the high current of the fast chargers and it could end up damaging the materials," he said.
To counteract this issue, the new batteries will self-heat for 30 seconds, facilitating fast charging regardless of the outside temperature. As a result, charging times will decrease to around 10 minutes for an 80-percent charge.
"This could become a major selling point for customers," Chao-Yang Wang said. "Once we create this, it can be commercialized very quickly."
The corresponding fast chargers are already being installed around the country, with over 2,000 from Tesla and other companies investing in electric vehicles planned by 2019.
"This timeline corresponds with our research, to bring this battery to market as well," Chao-Yang Wang said.
His team will also develop new electrolytes needed within the batteries that can tolerate these higher temperatures.
This new initiative is possible due to research previously conducted by this group, which discovered batteries' rapid self-heating capability.
The team is conducting their research at the Battery & Energy Storage Technology (BEST) Center, a multidisciplinary collaboration for cutting-edge energy-storage science and technology.
"At the BEST Center, we are fortunate to have the faculty, the leadership, and the facilities that are difficult to be matched elsewhere," Chao-Yang Wang said.
As one of nine projects funded by the DoE, Chao-Yang Wang commended the support of this critical research.
"Government funding is so important for science and technology that can have common interest and applications," he said. "As electric vehicles become mainstream, we need to make sure we have the latest, best technology to compete."