Many travelers carry smartphones, laptops, tablets, power banks, and other electronic devices when flying.
While these devices are convenient, the lithium-ion batteries inside them can sometimes become dangerous.
A new study has found that the current 100 watt-hour (Wh) limit for batteries in carry-on electronic devices remains an important safety rule for air travel.
The research was carried out by scientists from the Fraunhofer Institute in Germany in partnership with Airbus as part of the LOKI-PED project.
The goal was to better understand what happens if a lithium-ion battery overheats or catches fire inside an aircraft.
Lithium-ion batteries can become dangerous if they are damaged, crushed, or overheated. For example, a phone or laptop trapped between airplane seats could become damaged.
Charging devices improperly can also cause batteries to overheat. In rare cases, the batteries can enter a process called “thermal runaway,” where the battery rapidly overheats, releases flammable gases, and may catch fire or even explode.
According to the U.S. Federal Aviation Administration (FAA), incidents involving lithium-ion batteries now occur about once or twice every week on commercial flights.
To study these risks, researchers performed a series of experiments using aircraft cabin test facilities that closely resemble real passenger airplanes.
They heated laptops, smartphones, and tablets until their batteries failed, allowing them to observe how much heat, smoke, and gas were produced during battery fires.
The team found that larger batteries release more heat and more gases when they fail. This is one reason why airlines limit passengers to carrying devices with batteries no larger than 100 Wh. Many modern laptops already come close to this limit, and future battery technologies may exceed it.
After analyzing the test results, the researchers concluded that the current 100 Wh limit remains appropriate and helps reduce the risks of battery fires on aircraft.
The scientists also measured the gases released during battery failures. These included carbon monoxide, formaldehyde, hydrogen fluoride, and other harmful chemicals. Using computer simulations, they studied how these gases would spread through an aircraft cabin.
The results were reassuring. Modern aircraft ventilation systems quickly dilute smoke and gases. Two rows away from the burning device, gas levels stayed below health safety limits, and dense smoke was mostly limited to the area close to the fire.
The study also examined equipment designed to deal with battery fires. Researchers tested fire extinguishers and special fire-resistant bags that are marketed for containing burning electronic devices.
The fire extinguishers successfully put out the flames. However, none of the protective bags completely prevented smoke or flames from escaping. Airline cabin crew also tested the bags and suggested that future designs should be easier to use during emergencies, without requiring extra assembly.
The researchers say the findings show that air travel remains very safe. Flight attendants already receive extensive training on how to respond if a battery catches fire, including extinguishing flames and cooling the device as quickly as possible.
The study also highlights the importance of continuing to improve safety equipment as battery technology evolves.
As electronic devices become more powerful, ongoing research will help ensure that passengers, airlines, and aircraft manufacturers can continue to manage battery risks while keeping air travel safe for everyone.
