Lithium-ion batteries without fire risk developed

Scientists have developed novel lithium-ion batteries with components that harden on impact, preventing them from catching fire and causing injuries to users.

Lithium-ion batteries commonly used in consumer electronics are notorious for bursting into flame when damaged or improperly packaged.

These incidents occasionally have grave consequences, including burns, house fires and at least one plane crash. Inspired by the property of some liquids that solidify on impact, researchers have developed a practical and inexpensive way to help prevent these fires.

"In a lithium-ion battery, a thin piece of plastic separates the two electrodes," said Gabriel Veith, from US Department of Energy's (DOE) Oak Ridge National Laboratory.

"If the battery is damaged and the plastic layer fails, the electrodes can come into contact and cause the battery’s liquid electrolyte to catch fire," said Veith.

To make these batteries safer, some researchers instead use a nonflammable, solid electrolyte. However, these solid-state batteries require significant retooling of the current production process, Veith said.

As an alternative, the team mixes an additive into the conventional electrolyte to create an impact-resistant electrolyte.

It solidifies when hit, preventing the electrodes from touching if the battery is damaged during a fall or crash. If the electrodes don't touch each other, the battery doesn't catch fire.

One of Veith's major advances involves the production process for the batteries. During manufacture of traditional lithium-ion batteries, an electrolyte is squirted into the battery case at the end of the production process, and then the battery is sealed.

"You can;t do that with a shear-thickening electrolyte because the minute you try to inject it, it solidifies," he said.

The researchers solved this by putting the silica in place before adding the electrolyte. They are seeking a patent on their technique.

In the future, Veith plans to enhance the system so the part of the battery that's damaged in a crash would remain solid, while the rest of the battery would go on working.

The team is initially aiming for applications such as drone batteries, but they would eventually like to enter the automotive market. They also plan to make a bigger version of the battery, which would be capable of stopping a bullet.

That could benefit soldiers, who often carry 20 pounds of body armor and 20 pounds of batteries when they are on a mission, Veith said.

"The battery would function as their armour, and that would lighten the average soldier by about 20 pounds," he said. PTI MHN