Researchers explored the reason for poor performance of lithium ion batteries at cold temperatures.
Lithium-ion batteries exhibit poor performance in cold weather, and this limits its applicability in some of the major applications such as electric vehicles in cold areas, and a drone on Mars. Storing lithium ion batteries at freezing temperatures can crack some parts of the battery and separate them from surrounding materials, reducing their electric storage capacity.
Researchers at the Department of Energy’s SLAC National Accelerator Laboratory have identified the problem associated with the poor performance of the batteries. They made the discovery while looking at the cold-weather performance of the cathode, in which the electrons flow when in use.
To understand the reason for poor performance in cold weather, the researchers used a combination of X-ray analysis methods and machine learning techniques. This allows them to identify individual cathode particles, which means that the team could study thousands of particles at once.
“Together, those methods revealed that cold temperatures were shrinking the meatball-like particles within the cathode and in the process cracking them—or making existing cracks even worse,” Liu said. “And, since materials differ in the way they expand and contract in response to changing temperatures, extreme cold was also detaching the cathodes from surrounding materials.”
“The results point to some possible fixes,” Liu said. “By looking for battery materials that are better matched in terms of their temperature response, scientists could address the detachment issue. Doing so could help improve other batteries as well, since all batteries expand and contract as they heat up and cool down. And by engineering different particle structures inside a battery—notably, building them up from smoother, less meatball-like particles—researchers could help prevent cracking and improve long-term lithium-ion battery capacity.”
The research appeared in the journal Advanced Energy Materials.