A car with a brand-new battery sits in a driveway on a hot summer day in Arizona. Then disaster strikes: The battery catches fire.
The battery combusted because of a phenomenon called “thermal runaway.” When the battery is heated to a certain temperature, a reaction occurs and causes the battery to generate heat, until eventually it decomposes.
Luckily, this situation virtually never happens, and that’s because of people like Carrie Kaplan. Kaplan, a fourth-year graduate student in chemistry at Binghamton University, is part of Battery 500, a project aimed at developing next-generation batteries with higher energy capacity. It’s her job to make sure these batteries are stable.
Thermal runaway issues were the cause of Boeing 787 fires that happened in recent years. These issues typically arise when batteries have a larger energy capacity.
“As you increase the energy level, the safety goes down,” says M. Stanley Whittingham, director of Binghamton’s Northeast Center for Chemical Energy Storage (NECCES) and Kaplan’s advisor. “So you have this tradeoff between storage and safety.”
Kaplan studies thermal stability and searches for unwanted side reactions that may lead to decomposition. Using a differential scanning calorimeter, she increases the temperature of batteries and looks at changes in heat release.
If there is a high amount of heat released at a particular temperature, it indicates an unwanted reaction is occurring. That’s fine if the temperature, called the onset temperature, is high and relatively unreachable in a typical setting.
If the onset temperature is low, however, say 150°C, that’s a concern. That’s a temperature that can be feasibly reached, especially if the battery is in a car sitting on asphalt during a hot Arizona day.
Finding out what causes this decomposition is the challenge in Kaplan’s work. She is always moving around departments and using different technologies to understand what issues might arise.
“Is it because they’re organic? Is it because of the salt? Is it because of our material?” Kaplan wonders. “There’s a lot of different things that it could be, and we have to do further analysis to understand what exactly is happening.”
Kaplan, who’s from Ashburn, Virginia, did not expect to end up in battery work. At the Virginia Polytechnic Institute, she changed her major five times before ending up in chemistry because of an enthusiastic teacher.
“I took her class and knew that I was meant to do this,” Kaplan says. “She was so carefree. She would do these experiments in class, and I cannot count the amount of times she set the classroom on fire.”
While contemplating graduate school, Kaplan found out about the battery research at Binghamton, and she reached out to Whittingham.
“She’s a nice, easy person to work with, and a very good student,” Whittingham says.
Kaplan won the Lois D. Mackey Award, which goes to an outstanding first-year teaching assistant in general chemistry, and she received the Provost’s Doctoral Fellowship in the summers of 2017 and 2018. Now, she is the “safety and side reaction expert” for Battery 500.