The world welcomes the achievement of scientists from Stanford University—a rechargeable lithium-ion battery with overheating control. The battery is fitted with the function of switching off when the temperature gets higher than normal and turning back on when the battery is cool enough.
The main benefit of the innovation is the ability to prevent the battery fires that often occur in laptops, phones, hoverboards, and other electronics.
Zhenan Bao, a Stanford professor of engineering, claims that many ways of solving the problems of fires in lithium batteries have been tried. He assures that their scientists have designed the first and one-of-a-kind battery that repeatedly switches off and powers back on without lowering its productivity.
The lithium battery is rechargeable due to its construction: the space between positive and negative electrodes is filled with intermediary electrolyte liquid/gel that makes the ionic movement possible.
Hoverboards are popular nowadays for the ability to levitate above the ground. Unfortunately, there are dozens of videos on Youtube channels that have documented spontaneous lithium battery explosions. The reason is the rise of temperature of the battery’s electrolyte material above 300 degrees Fahrenheit.
Seeking to solve the problem, the scientists found out that a thin film of elastic polyethylene placed between the electrodes and the electrolyte acts as a governor. In addition, the film contains spiky nickel nanoparticles coated with graphene to increase the conductivity of the battery.
To make the electric current flow through the battery, we connected the polyethylene film to one of its electrodes, says Zheng Chen, a Stanford postdoctoral scholar. He informs that in order to create electricity conduction, the spiky particles have to be side by side, physically contacted. But in case of thermal expansion, there appeared the new problem—the polyethylene began to stretch, forcing the spikes to spread apart and stop the flow of electricity through the battery.
The researchers made the film calibrated so that the particles would separate only when the defined temperature was reached. In the first battery’s prototype, Stanford scientists designed the film that spreads at the right pace for the nanoparticles, and the switching off takes place at the temperature above 160 degrees Fahrenheit.
As the journal Nature Energy reports, the innovation was tested using a hot air gun, and the results showed the accuracy, efficiency, and the reversibility of the battery safety mechanism. The battery resumes its work after the temperature falls below 160 degrees Fahrenheit.
Yi Cui, the engineer at Stanford, declares that they have achieved an incredible breakthrough in technology, providing both high battery capacity and safety. Their reversible, reliable, and fast strategy has great outlooks for practical battery usage in the near future.