Short Bytes: The scientists at Stanford have created world’s first lithium-ion batteries that shut down at high temperature. This invention will prevent devices from catching fire and exploding due to overheating. This new method operates mechanically and repetitively to avoid overheating, due to a material composed of tiny particles of nickel with nanoscale spikes protruding from their surface.
The above finding is reported in Nature Energy, and it’s capable of benefiting all types of lithium ion battery-based devices that are prone to overheating risks, including smartphones, tablets, and notebook computers.
Why batteries explode?
The reason behind overheating of batteries is that Traditional lithium-ion batteries comprise a pair of electrodes and a liquid or gel electrolyte that carries charged particles between them. But once, the battery’s temperature reaches around 150 degrees Celsius (300 degrees Fahrenheit) due to some defect or overcharging the electrolyte can catch fire and trigger an explosion,
Previously, Scientists have made such attempts to prevent overheating of hover boards, by implementing things like flame retardants and copper separators to forestall potential fire hazards. But that didn’t prove to be much effective because those techniques proved to be irreversible, thereby rendering the battery dysfunctional once they were overheated.
How the new Stanford battery works?
But the new method operates mechanically and repetitively to avoid overheating, due to a material composed of tiny particles of nickel with nanoscale spikes protruding from their surface. These nickel particles are coated with graphene and embedded in a thin film of elastic polyethylene that facilitates the flow of electric current through it.”
To conduct electricity, the spiky particles have to physically touch one another. But during thermal expansion, polyethylene stretches. That causes the particles to spread apart, making the film non-conductive so that electricity can no longer flow through the battery.”
While developing these batteries, the researchers applied heat to the battery with a hot-air gun. As soon as the temperature reached above 70 degrees Celsius (160 degrees Fahrenheit), the polyethylene film expanded and caused the battery to shut down, but once the temperature dipped, the film shrank automatically, thereby resuming the electricity generation.
According to the researchers, the temperature threshold could be changed depending on the particular composition of the polymer materials, enabling batteries to run cooler or hotter before the conduction/non-conduction kicks in.
It’s a much reliable and faster approach with a promise for better performance and improved safety.