Penn State, EC Power use internal thermal modulation to enable stable fast charging

A team from Penn State University and start-up EC Power has developed a material-agnostic technology based on asymmetric temperature modulation with a thermally stable dual-salt electrolyte to achieve stable fast charging for Li-ion batteries.

In a paper in Nature, the team reports charging of a 265 Wh kg−1 battery to 75% (or 70%) state of charge in 12 (or 11) minutes for more than 900 (or 2,000) cycles. This is equivalent to a half million mile range in which every charge is a fast charge.

Further, we build a digital twin of such a battery pack to assess its cooling and safety and demonstrate that thermally modulated 4C charging only requires air convection. This offers a compact and intrinsically safe route to cell-to-pack development. The rapid thermal modulation method to yield highly active electrochemical interfaces only during fast charging has important potential to realize both stability and fast charging of next-generation materials, including anodes like silicon and lithium metal.

This 10-min fast-charging battery was developed for electric cars, with the black box on the top containing a battery management system to control the module. Credit: EC Power.

Our fast-charging technology works for most energy-dense batteries and will open a new possibility to downsize electric vehicle batteries from 150 to 50 kWh without causing drivers to feel range anxiety. The smaller, faster-charging batteries will dramatically cut down battery cost and usage of critical raw materials such as cobalt, graphite and lithium, enabling mass adoption of affordable electric cars.

The technology relies on internal thermal modulation, an active method of temperature control to demand the best performance possible from the battery, Wang explained. Batteries operate most efficiently when they are hot, but not too hot. Keeping batteries consistently at just the right temperature has been major challenge for battery engineers. Historically, they have relied on external, bulky heating and cooling systems to regulate battery temperature, which respond slowly and waste a lot of energy, Wang said.

Wang and his team decided to instead regulate the temperature from inside the battery. The researchers developed a new battery structure that adds an ultrathin nickel foil as the fourth component besides anode, electrolyte and cathode. Acting as a stimulus, the nickel foil self-regulates the battery's temperature and reactivity which allows for 10-minute fast charging on just about any EV battery, Wang explained.

"True fast-charging batteries would have immediate impact," the researchers write. "Since there are not enough raw minerals for every internal combustion engine car to be replaced by a 150 kWh-equipped EV, fast charging is imperative for EVs to go mainstream."

EC Power is working to manufacture and commercialize the fast-charging battery for an affordable and sustainable future of vehicle electrification, Wang said.

EC Power's Thermally Modulated Cell Technology (TMCT) heats cells from the inside out.

The other coauthors on the study are Teng Liu, Xiao-Guang Yang, Shanhai Ge and Yongjun Leng of Penn State and Nathaniel Stanley, Eric Rountree and Brian McCarthy of EC Power.

The work was supported by the US Department of Energy, the US Department of Defense, the US Air Force and the William E. Diefenderfer Endowment.

Resources

Wang, CY., Liu, T., Yang, XG. et al. (2022) "Fast charging of energy-dense lithium-ion batteries." Nature doi: 10.1038/s41586-022-05281-0

Posted on 03 November 2022 in Batteries, Electric (Battery) | Permalink | Comments (0)