At least seven people were injured in a five-alarm fire in the Bronx, which required the attention of 200 firefighters. Officials believe the incident stemmed from a lithium-ion battery of a scooter found on the roof of an apartment building. In 2022, the New York City Fire Department responded to more than 200 e-scooter and e-bike fires, which resulted in six fatalities.
“In all of these fires, these lithium-ion fires, it is not a slow burn; there’s not a small amount of fire, it literally explodes,” FDNY Commissioner Laura Kavanagh told reporters. “It’s a tremendous volume of fire as soon as it happens, and it’s very difficult to extinguish and so it’s particularly dangerous.”
These incidents are becoming more common for a number of reasons. For starters, lithium-ion batteries are now in numerous consumer tech products, powering laptops, cameras, tablets and more. They allow companies to squeeze hours of battery life and faster charging capability into increasingly slim devices. But a combination of manufacturer issues, misuse and aging batteries can heighten the risk from the batteries, which use flammable materials.
“Lithium batteries are generally safe and unlikely to fail, but only so long as there are no defects and the batteries are not damaged or mistreated,” said Steve Kerber, vice president and executive director of Underwriters Laboratory’s (UL) Fire Safety Research Institute (FSRI). “The more batteries that surround us the more incidents we will see.”
All lithium-ion batteries use flammable materials, and incidents such as the one in the Bronx are likely the result of “thermal runaway,” a chain reaction which can lead to a fire or catastrophic explosion, according to Dylan Khoo, an analyst at tech intelligence firm ABI Research. “This process can be triggered by a battery overheating, being punctured, or an electrical fault like a short circuit,” Khoo said. “In cases where fires occur spontaneously while charging, it is likely due to manufacturing defects.”
“It will continue to happen until there are regulations around the quality of these devices,” Kerber said.
Kerber recommends people buy UL-certified electric bikes and scooters from reputable retailers; online marketplaces often make it hard for customers to tell where products are actually coming from. If a fire occurs, he advised people to evacuate and call 911 immediately rather than trying to put it out themselves.
“The fire spreads incredibly fast and a fire extinguisher is not effective,” he said.
Beyond scooters and e-bikes, experts advise anyone with a lithium-ion battery to follow proper charging and battery usage guidelines. According to researchers at the University of Michigan, any device with this kind of battery should be charged on a non-flammable surface and stored in a cool, dry place, and not left charging for too long, unattended or while you’re asleep.
“Elevated temperatures can accelerate degradation of almost every battery component and can lead to significant safety risks, including fire or explosion,” the researchers said. “If a laptop or cellphone is noticeably hot while it’s charging, unplug it.”
Batteries should also be routinely inspected to make sure there is no cracking, bulging or leaking, and people should always use the charger that came with the device or use one from a reputable supplier. When charging an electric scooter or bike, Kerber said it should never block a fire escape or exit route.
Although some battery chemistries are safer than others, we are still a few years away from adoption of a better, safer lithium-ion alternative, according to Sridhar Srinivasan, a senior director at market research firm Gartner.
For example, LFP (lithium iron phosphate) batteries don’t overheat as much as other types of lithium-ion batteries. Future battery technologies in development, such as sodium-ion or solid state batteries, are also expected to address some of the safety issues of lithium ion.