Keeping the Powerpacks Under Control
There was a time when “batteries not included” was the standard delivery configuration for new devices, and the go-to powerpack consisted of heavy cylindrical alkaline batteries in sizes from AAA to D. There are still plenty of alkaline-battery-powered devices out there. However, today’s tablets, mobile phones, laptops, and other such items owe their sleek, featherweight design to better battery technology, such as rechargeable lithium ion (Li-Ion) and non-rechargeable lithium metal batteries.
Chances are good that the unseen powerpack sealed into your favorite portable device is a lithium ion (Li-Ion) rechargeable battery. That’s because Li-Ion batteries provide an almost unbeatable combination of light weight, high capacity, and none of the “memory effect” that plagues nickel cadmium (Ni-Cad) batteries. So what’s not to like?
The downside to lithium batteries, both lithium metal and Li-Ion, is that mishandling, misuse, or malfunction (e.g., internal short-circuit failures) can result in a roaring fire. Like all battery types, Li-Ion batteries operate through a controlled chemical reaction that generates electrical energy (current) and transmits power through terminals made of conductive metal. This process inevitably generates some degree of heat. The danger arises when problems lead to an uncontrollable, rapid increase in temperature and pressure within the battery cells. This condition could result in a battery fire and, due to the construction of Li-Ion batteries, failure in a single battery cell could initiate fire in adjacent battery cells.
For this reason, Li-Ion battery fires are particularly difficult to suppress or extinguish. As a 2010 FAA Safety Alert for Operators (SAFO) states:
Our test results have also demonstrated that lithium-ion cells are flammable and capable of self-ignition. Self-ignition of lithium-ion batteries can occur when a battery short circuits, is overcharged, is heated to extreme temperatures, is mishandled, or is otherwise defective. Like lithium metal batteries, lithium-ion batteries can be subject to thermal runaway. A battery in thermal runaway can reach temperatures above 1,100 degrees F, which exceeds the ignition temperature of most Class A materials, including paper and cardboard. These temperatures are also very close to the melting point of aluminum (1,220 degrees F).
Keeping the Li-Ion Caged
The FAA and other organizations such as the U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA), continue to research these issues, as well as develop possible new safety rules and guidance for both flight crews and passengers. Though the tips below were developed for airline crews and passengers, GA pilots and their passengers can also benefit from following this advice:
Keep batteries installed in portable electronic devices. Leaving batteries in battery-powered devices is an effective means of insulating the terminals and protecting against short-circuiting.
When replacing with a spare battery during flight, handle batteries with care.
Pack spare batteries in baggage that is accessible during flight – you certainly do not want a Li-Ion battery fire to start and propagate in a baggage compartment you can’t reach.
Keep spare batteries in the original retail packaging. Because it is designed for the transport of those batteries, this packaging prevents unintentional activation and short-circuiting by effectively isolating the batteries from contact with each other and other objects.
If original packaging is not available, place each battery individually in its own protective case, plastic bag, or package. A sturdy, re-sealable plastic bag (e.g., a freezer bag) is suitable for this purpose. Covering the battery terminals with insulating tape, such as electrical tape, is another effective method.
What If …?
If, despite all precautions, you do find yourself facing a hungry Li-Ion fire, testing by the Fire Safety Branch of the FAA’s William J. Hughes Technical Center has resulted in the following tips for fighting lithium-type-battery fires. These procedures consist of two phases: (1) extinguishing the fire, and (2) cooling the remaining cells to stop thermal runaway.
To extinguish the blaze, use a Halon, Halon replacement, or water extinguisher to douse the fire and prevent its spread to additional flammable materials.
After extinguishing the fire, douse the device with water or other non-alcoholic liquids to cool the device and prevent additional battery cells from igniting. Do not cover the device or use ice in an attempt to cool it, because these actions will insulate the device and increase the possibility that additional battery cells will ignite. (FAA Safety Briefing – JanFeb 2014)