A demonstration by firefighters in Sarasota, Florida, has shown how quickly lithium-ion batteries can erupt into flames, prompting renewed warnings after the devices were linked to seven structure fires in the county this year.
Footage recorded at the Sarasota County Fire Department’s Fire Academy shows individual cells repeatedly igniting and projecting flames from the battery, producing an explosion-like reaction.
Lithium-ion battery fires can reignite hours later
Assistant Chief of Operations Casey Kelch said the danger could remain even after visible flames had disappeared, as heat trapped within a damaged cell can trigger a delayed fire.
“One of the challenges is you can’t always tell, but it’s hot inside the cell, so if you have visible fire, that’s easy, but sometimes the cell is so hot inside that it can lay hours, sometimes even days later,” Kelch said.
The process, known as thermal runaway, occurs when rising temperatures inside a battery cell cause a rapid chain reaction. Lithium-ion batteries are used in a wide range of everyday products, including mobile phones, e-bikes, scooters, golf carts and electric vehicles.
The warning follows a June fire in Sarasota County in which officials said a lithium-ion battery charging for an e-bike ignited inside a family home. The property was left uninhabitable and seven people were displaced, although no injuries were reported.
Fire officials said members of the public should not attempt to remove a burning battery or tackle the fire themselves. A battery can ignite while it is being handled, potentially causing serious injury.
“If you do have a fire, you need to call 911 right away,” Kelch said. “Don’t try to waste time putting it out yourself, removing the battery itself, because it can catch on fire while you’re holding it and create an injury.”
Signs that a battery may be failing include swelling, excessive heat, unusual smells, leaking, and popping or hissing sounds. Anyone who notices a battery becoming unusually hot should unplug it if it is safe to do so and keep away from it.
Residents have also been advised to use the charger supplied or recommended for their device rather than an unsuitable aftermarket alternative. Firefighters say e-bikes and scooters may be charged overnight, but any battery that becomes excessively hot should be disconnected and monitored carefully.
Kelch said the department’s aim was to raise awareness of the risks and reduce the number of battery-related fires in Sarasota County.
