Electric car batteries may need some tweaking to work at their best in winter climates.
Wesley Chang, assistant professor of mechanical engineering and mechanics at Drexel University, explores solutions.
Wes Chang is an Assistant Professor in the Department of Mechanical Engineering and Mechanics, and an affiliated faculty member of the Department of Materials Science and Engineering and the Department of Chemical and Biological Engineering, at Drexel University. Prof. Chang completed his B.S. (2014) and M.S. (2016) in Chemical Engineering at Stanford, and his Ph.D. (2021) in Mechanical Engineering and Materials Science at Princeton. After completing his doctoral thesis, he continued working on lithium metal batteries as a Postdoc at Columbia University (2021 – 2022). He spent the following year (2022 – 2023) as the Beckman Postdoctoral Fellow at Caltech, where he worked on lithium-mediated electrochemical ammonia synthesis. He is the recipient of the Electrochemical Society F.M. Becket Fellowship and the Arnold O. Beckman Postdoctoral Fellowship. Outside of academia, he has previously worked in the battery industry and management consulting for energy and utilities, and regularly serves as a technical advisor to energy-focused startup companies and investment firms.
Optimizing Electric Vehicle Battery Performance in Cold Weather Climates
With each passing year, we see a greater proportion of electric vehicles on the road. This is expected to further accelerate with the start of gigafactory battery production from many of the largest automotive manufacturers in the United States. Electric vehicles use rechargeable Li-ion batteries, which are sensitive to environmental conditions such as temperature. In particular, electric vehicles that are driven in the frigid winters of the Midwest and Northeast may suffer from poor performance and an increased risk of failure.
Why are Li-ion batteries not optimized for the cold? Batteries contain fluids called electrolytes, and cold temperatures cause fluids to flow more slowly. So, the electrolytes in batteries slow and thicken in the cold, causing the lithium ions inside to move slower. This slowdown can prevent the lithium ions from properly inserting into the electrodes when the battery is charging. Instead, they may deposit on the electrode surface and form lithium metal deposits. If too much lithium metal deposits on the electrode’s surface during charging, it may cause an internal short circuit. This process can start a battery fire.
There are several ways of improving battery performance in the cold. For one, electrolytes that are less thick can be used, as they may operate more efficiently at low temperatures. Another potential solution is to pre-heat the battery before charging so that they are charged at warmer temperatures. Finally, improved sensors and battery management systems for rapidly detecting potential failure and low temperature warnings may help to identify issues before they become a problem. Lithium-ion batteries power technologies that people across the country use every day, and research on improved low temperature performance aims to find solutions that will make this technology even safer for the consumer.
