Tuesday, 12 January 2016

Lithium-Ion Batteries That Don't Explode? Stanford Researchers Have an Answer

Lithium-Ion Batteries That Don't Explode? Stanford Researchers Have an Answer
The future iterations of lithium-ion battery could be significantly better at handling overheating issues. Stanford researchers have developed a lithium-ion battery that automatically shuts down before overheating and restarts when it has cooled off to a specified temperature range.
The advancement could solve one of the biggest shortcomings in the lithium-ion battery. The lithium-ion have a tendency to overheat and at times, explode. This is the reason why some hoverboards, which come equipped with lithium-ion batteries, catch on fire, and are not allowed to be carried on an aeroplane. Over the years, we have seen such incidents affecting smartphones as well.
"People have tried different strategies to solve the problem of accidental fires in lithium-ion batteries,"said Zhenan Bao, a professor of chemical engineering at Stanford. "We've designed the first battery that can be shut down and revived over repeated heating and cooling cycles without compromising performance."
Coming to the science behind this achievement, researchers are attaching a polyethylene film to one of the battery electrodes. Polyethylene film, which is coated with nickel and graphene, stretches in an event of heat and spreads apart. This makes the film non-conductive, stopping the electricity flow through the battery. The polyethylene, as you can see, serves as a self-resetting circuit breaker.
"We can even tune the temperature higher or lower depending on how many particles we put in or what type of polymer materials we choose," said Bao. "For example, we might want the battery to shut down at 50 C [122 F] or 100 C."
The researchers tout the film's stability, adding that they performed a range of tests including repeatedly applying heat to the battery with a hot-air gun. The battery switched off every time it got hot and restarted when the temperature was back to the accepted level. As of now, there is no word on when this technology will become available for commercial usage.