New Battery Technology Promises to Short Circuit Overheating Issues

Researchers from Stanford University in California say they have developed a thermo-responsive polymer switching material to reduce the potential for lithium-ion batteries to overheat and spark a fire. The group details its findings in the journal Nature Energy.

The new technology is more sensitive and faster-acting than previous techniques, according to the researchers. It also is reversible—allowing batteries to resume operation when conditions permit—which isn’t possible with the use of flame retardants and other traditional safeguarding measures.

Using a nanomaterial and sensor invented by team member Zhenan Bao to monitor human body temperatures, the researchers say the new battery system is as much as 10,000 times more sensitive to temperature changes than previous switching devices.

The new sensor, which is integrated inside of the battery, is made of a plastic material embedded with tiny particles of nickel with nanoscale spikes protruding from their surface. During thermal expansion, the polyethylene stretches, causing the particles to spread apart, thereby making the film nonconductive so electricity can no longer flow through the battery.

Reaction temperatures can be varied by application. During testing, the researchers set the threshold at 70˚C.