From laptops, cell phones, and tablets to electronic cigarettes, power banks, and electric toothbrushes, rechargeable lithium-ion batteries are in most of our portable electronic gadgets.
While they’ve been revolutionary in charging our devices and making them on-the-go ready, actually traveling with them can be a hassle. Federal rules mandate that they’re not allowed in airline passengers’ checked bags—they must go in carry-on luggage or be left home. Why, though?
According to University of Michigan professor Venkat Viswanathan, an expert in batteries for aviation, they “pose a flight risk,” because they’re capable of overheating or short-circuiting, especially if they are damaged. This, in turn, can lead to a process called thermal runaway, resulting in smoke, flames, and, in some cases, explosions.
“If one of them catches fire, then very quickly, the entire cargo hold could be in flames,” Viswanathan said.
John Cox, CEO of aviation consulting firm Safety Operating Systems and a former pilot, added that while thermal runaway isn’t ideal in either the cabin or in cargo, if a battery does begin to smoke or catches fire, flight attendants can respond to the issue more quickly in the cabin.
While thermal runaway events are rare, they do happen. In February 2023, for instance, a laptop caught fire in the cabin of a plane shortly after takeoff. The flight returned to San Diego International Airport, and four flight attendants were taken to the hospital.
According to the Federal Aviation Administration, there have been 481 verified incidents involving lithium batteries between March 3, 2006, and August 31, 2023. Of those, at least 343 incidents happened in the cabin and 112 in the cargo hold (the remaining 26 were not classified). The most common issue involved battery packs (199 incidents), followed by e-cigarettes (101), cellular phones (63), other electronic devices (58), laptop computers (57), and medical devices (3).
The number of incidents has trended upward every year since 2014, with the exception of 2019 and 2020.
Between January 1 and August 23, 2023 (when the FAA most recently updated its online incident report), there were 50 incidents. In 2022, there were 74 incidents in total.
Cox said he expects that the “number of lithium battery fires, on airplanes and elsewhere, will continue to increase. This is due to the increase of lithium batteries in our society.”
To help reduce the risk of these incidents, the FAA encourages fliers to check for recalls or damages to their devices, as they’re more “likely to create sparks or generate a dangerous evolution of heat.”
Passengers can also protect themselves and others by keeping electronics in a sleeve or case. If a device is squeezed too hard, it could damage the battery, which could cause thermal runaway—a little cushion from protective casing helps prevent that from happening. Similarly, if your cell phone falls between the seats, it’s important not to move the seat—if it gets damaged, the battery might smoke or catch fire. Flight attendants are trained to retrieve phones safely.
Furthermore, passengers can prevent thermal runaway on planes by turning devices completely off when not in use.
If your device should overheat, smoke, or ignite midflight, contact a crew member immediately. They have fire extinguishers and thermal containment bags, which restrict oxygen to the device and prevent the spread of fire, to help neutralize the danger.