Stanford University scientists have developed a "smart" lithium-ion battery that gives ample warning before it overheats and bursts into flames. The new technology is designed for conventional lithium-ion batteries now used in billions of cellphones, laptops and other electronic devices, as well as a growing number of cars and airplanes.

"Our goal is to create an early-warning system that saves lives and property," said Yi Cui, an associate professor of materials science and engineering at Stanford. "The system can detect problems that occur during the normal operation of a battery, but it does not apply to batteries damaged in a collision or other accident."

Cui and his colleagues describe the new technology in a study published in the Oct. 13 issue of the journal Nature Communications.

Lowering the odds

A series of well-publicized incidents in recent years has raised concern over the safety of lithium-ion batteries. In 2013, the Boeing aircraft company temporarily grounded its new 787 Dreamliner fleet after battery packs in two airplanes caught fire. The cause of the fires has yet to be determined.

In 2006, the Sony Corporation recalled millions of lithium-ion batteries after reports of more than a dozen consumer-laptop fires. The company said that during the manufacturing process, tiny metal impurities had gotten inside the batteries, causing them to short-circuit.

"The likelihood of a bad thing like that happening is maybe one in a million," Cui said. "That's still a big problem, considering that hundreds of millions of computers and cellphones are sold each year. We want to lower the odds of a battery fire to one in a billion or even to zero."

A typical lithium-ion battery consists of two tightly packed electrodes -- a carbon anode and a lithium metal-oxide cathode -- with an ultrathin polymer separator in between. The separator keeps the electrodes apart. If it's damaged, the battery could short-circuit and ignite the flammable electrolyte solution that shuttles lithium ions back and forth.

"The separator is made of the same material used in plastic bottles," said graduate student Denys Zhuo, co-lead author of the study. "It's porous so that lithium ions can flow between the electrodes as the battery charges and discharges."