Developing Hybrid Battery Management Systems to Protect Freezing Batteries

MIE Assistant Professor Juner Zhu and MIE Professor Hongwei Sun are exploring how to better protect batteries from extreme temperatures by determining what happens during exposure and developing a temperature management system to regulate battery temperatures.

This article originally appeared on Northeastern Global News. It was published by Cyrus Moulton. Main photo: Hongwei Sun, Northeastern University professor Mechanical and Industrial Engineering, is developing a hybrid battery management system to protect lithium ion batteries in extreme temperatures. Photo by Matthew Modoono/Northeastern University

Why Teslas froze in Chicago’s cold snap, and how battery research at Northeastern might prevent future freezes

As if the chill isn’t bad enough for humans, Tesla owners near Chicago this winter learned that subzero temperatures aren’t too good for electric vehicle batteries either, with many motorists stranded in dead cars and/or awaiting extra long charges.

Northeastern University battery experts Juner Zhu and Hongwei Sun are working to prevent similar occurrences in the future — focusing, respectively, on what happens when batteries are exposed to extreme cold temperatures, and developing a temperature management system to regulate battery temperatures.

“Keeping batteries in the right temperature — that is a very big task for everyone in this community,” Zhu says of the scientific community researching batteries. “Cold weather is actually very bad for batteries.”

Juner Zhu, assistant professor of mechanical and industrial engineering, conducts research on lithium ion batteries in extreme cold temperatures. Photo by Matthew Modoono/Northeastern University

Zhu is an assistant professor of mechanical and industrial engineering at Northeastern and the co-founder and executive director of the Center for Battery Sustainability, launched by Northeastern and the Massachusetts Institute of Technology. His lab studies battery performance in extreme cold temperatures — in fact, equipment enables him to expose batteries to the minus 70-degree Celsius temperatures that will be necessary for battery systems in Arctic conditions or even lower temperatures in outer space for trips to Mars.

Zhu explained the basics of a lithium ion battery and what happens to it when it’s cold.

In such a battery, lithium ions move between an anode and a cathode that are separated by an electrolyte and are each connected to an electric circuit. This movement results in electrons. When the battery is discharging, the lithium ions move from anode to cathode and the electrons move through the attached circuit and power a device. When the battery is charging, the lithium ions move in the opposite direction, resulting in electrons that repower the battery.

But in cold weather, the ions can’t move very easily, Zhu says.

Moreover, if the lithium ion is given an electron and it can’t readily move, then a side chemical reaction can occur, Zhu says. This side reaction is called “plating,” Zhu explains, as the lithium ion becomes a metal that — if built up — can penetrate the battery and cause a fire. Plating is also “almost irreversible,” decreasing the amount of lithium ions that can be used to generate electricity, Zhu says.

Hongwei Sun, professor of Mechanical and Industrial Engineering, conducts research in the Egan Research Center. Photo by Matthew Modoono/Northeastern University

Zhu’s research focuses on this plating process, including how it happens and how to detect it.

“It’s a very big challenge, I think,” Zhu says.

Read full story at Northeastern Global News

Related Faculty: Juner Zhu, Hongwei Sun

Related Departments:Mechanical & Industrial Engineering