Inventing a new self-preventing battery

A battery sensitive to temperature, thus preventing the risk of fire and equipment, newly invented in the United States.

Researchers from Stanford University (USA) have designed a lithium-ion battery that can turn itself off at high temperatures, to prevent battery explosion in different devices.

According to research results, just published in the American Natural Energy (Nature Energy) magazine, this battery can restart itself immediately, when the temperature cools down.

Ms. Zhenan Bao, a professor of chemistry at Stanford University, said: "We have designed the first battery that can turn itself off and restart itself on a repeated cycle of warming and cooling , but does not affect battery performance ".

The researchers used very thin polyethylene to prevent the battery from overheating leading to fire.(Source: Stanford University).

A lithium-ion battery typically has two electrodes and an electrolyte liquid, containing charged particles between these two electrodes. When the battery is exhausted or when overcharging, heat is usually generated. If the temperature reaches about 150 degrees Celsius, electrolytes can catch fire and cause an explosion.

Previously, at Stanford University, someone invented a battery that could give a warning when it got too hot. However, the limitation of this type of battery is that after cooling again, the battery does not work.

To solve this problem, the team used nanotechnology . The team invented a wearable sensor on the body to monitor body temperature. The sensor is made of plastic, with a coating of small nickel particles with nanoscale spines (ultra-small) protruding from their surface.

In the experiment, the team coated these spiked nickel particles with graphene - a layer of carbon that is only as thick as an atom, and dipped these particles into a thin film made of elastic polyethylene.

"We attached this polyethylene film to a battery electrode so that the current could flow through it. To conduct electricity, the spikes must come into contact with each other," said Chen, a co-author of the study. When the researchers heated the battery at temperatures above 70 degrees Celsius, the polyethylene film rapidly expanded, making the spines separate from each other and the battery turned off. And when the temperature drops back down to 70 degrees Celsius, the polyethylene layer shrinks, the particles come into contact again, and the battery starts generating electricity again.

"We can even adjust the temperature higher or lower depending on the number of particles we put in, or depending on the type of polymer material we choose," Ms. Bao said.