A New Conductive Layer — Like Cheese on a Burger — Could Help Prevent Lithium-Ion Battery Fires
Taking an alternative approach to rivals, NTU's patent-pending battery protection system lets dendrites grow into an added protective layer.
Scientists at the Nanyang Technical University, Singapore have come up with a method to reduce the risk of fire in lithium-ion batteries, protecting them from internal shorts.
"We know that for a Li-ion battery to work, Li-ions must be able to travel between the positive and negative sides during charge and discharge cycles," explains Xu Zhichuan, team lead and professor at NTU's School of Materials Science and Engineering. "However, the transfer of the Li-ions also means the formation of dendrites is inevitable for current commercial Li-ion batteries."
It's a very real problem: The formation of lithium dendrites can, over time, pierce the battery and cause a short circuit — resulting in a rather nasty lithium fire. It's bad enough when the it happens in a smartphone or laptop battery; it's considerably worse when it's the hefty batteries found in electric vehicles.
“Instead of preventing the formation of dendrites, we decided to make use of their intrinsic properties by coating an additional layer of conductive material on the separator for these dendrites to connect with," Xu continues. "Once the dendrites make the connection it will not be able to continue their growth further, thus preventing them from ever reaching the other side."
It's a very different approach to that taken earlier this year by an international group, which showcased a "hybrid separator membrane" designed to prevent dendrites from forming in the first place — not only protecting the batteries from short circuits but extending their usable lifespan to boot.
The layer, which NTU likens to a slice of cheese on a burger, is made using common materials and with existing manufacturing techniques — and adds as little as a five percent boost to production costs. NTU confirms it has applied for a patent on the technology, and that it is to commercialize it through its NTUitive division.
Precise details of the material used have not yet been publicly released.