After an on-board fire and the resulting crash of a UPS cargo plane that killed both pilots on Sept. 3, investigators are questioning the role that lithium-ion batteries – part of the plane’s cargo – may have played in the tragic accident. An MSNBC article says safety advocates have warned for years that air shipments of lithium-ion batteries, used in power tools, cameras, cell phones, laptops, and many other products, have the potential to either cause or exacerbate a fire on board an aircraft.

Update - January 2013: Boeing has grounded all of its 787 Dreamliners due to lithium-ion battery fires on board. Read more from CNN and the Los Angeles Times.
While investigators will not finalize their reports for some time, the potential involvement of lithium-ion batteries in this incident has recaptured the attention of the Federal Aviation Administration (FAA). The agency issued a Safety Alert for Operators in early October to educate pilots on the flammability of lithium-ion batteries and lays out recommendations for air carriers that transport the products.

With lithium-ion becoming the battery of choice for power tool users, we asked manufacturers for their insight into battery flammability and safe operation. “This is a very relevant topic, and very meaty because it’s global in scope,” says Dewalt product manager Jason McNeil. “A lot of influential and important industries are involved, as well as agencies like the FAA and even the United Nations because so many shipments of affected products are sent overseas.”

Quick-Fire Chemistry

Speaking about lithium-ion technology in general, McNeil says cobalt and other ingredients in the batteries are responsible for making them so flammable. “The combination of ingredients makes fires inextinguishable,” he says. “Also, the size of the packaging has gotten smaller in many cases, so the batteries have become more combustible.” According to the FAA’s notice to operators, ignition of the batteries can be caused when the battery short-circuits, is overcharged, heated to extreme temperatures, mishandled, or otherwise defective. When adverse conditions are present, a chain reaction occurs in the battery cell, releasing the stored energy. In a fire situation, the air temperature in a cargo compartment fire may be "above the auto-ignition temperature of lithium," causing the batteries to ignite and propagate the fire in to a “catastrophic event.”

As such, McNeil says DeWalt and other lithium-ion power tool manufacturers must follow specific guidelines for safe transport of the batteries. “The discussion of lithium-ion batteries has been going on for a long time, and several things have already happened to address safety issues,” he says. Guidelines include: • Careful packaging. “Power tool batteries have to be shipped in a way that guarantees they can’t be shorted out – nothing can come across the terminals,” McNeil says. For this reason, the batteries are often packaged in plastic bags, with caps snapped on, or latched into a kit box. Manufacturers can choose which option best suits their product.
• Low-charge shipments. “There are regulations as to how much state of charge can be in a battery when you ship it,” McNeil says, noting that a fully-charged battery has that much more potential to contribute to a fire situation. “They can’t ship completely empty, but they must not be shipped fully charged either.”
• No damaged packaging. If a forklift picks up a pallet of power tools and the forks puncture the packages, “those packages should be set aside and a manufacturer’s rep will deal with that shipment,” McNeil says. “For any power tool shipped that contains a lithium-ion battery, the package should say ‘do not transport if damaged, a fire hazard could exist.’ There’s also a universal call-in number that’s been in place for a year that users can call and determine the best way to deal with a damaged product.”

McNeil says that while DeWalt hasn’t visited any incident sites involving lithium-ion battery fires, it is the company’s understanding that most of the incidents have been caused by damaged packages being shipped.

Transportation & User Safety

According to the FAA, most lithium-ion batteries are considered Class 9 hazardous cargo. Class 9 cargo is placed in a special compartment for transportation, and pilots are given specific notice when such a shipment exists on their planes, as well as where it is located in the cargo hold. That said, McNeil notes that batteries are classified as small, medium or large based on their watt hour calculations. All DeWalt-branded batteries, as well as many other lithium-ion batteries, according to the FAA, are below the “large” category and are therefore exempt from Class 9 labeling, which means pilots may not be appraised of the shipments’ location on board. McNeil says pilots’ organizations and representatives from industries related to lithium-ion battery use are working with groups like the Rechargeable Battery Association to keep all air shipments safe and secure.

For the most part, the power tool industry is not using air transportation to move tool and battery shipments. McNeil says DeWalt ships by air only in special circumstances. Moreover, a recent Wall Street Journal article broke out information on the types of batteries shipped via air or sea. Laptop and cell phone batteries are shipped by air much more frequently than power tool batteries. 

“While most of our shipments are not sent via air transportation, power tool distributors need to understand their link in this chain, and need to be proactive with how they ship product,” McNeil says. “That means being aware of the dangers of damaged packaging and taking advantage of the manufacturer hotlines to contact the appropriate people when there is damage.”

For end-users, McNeil says multiple safety mechanisms are built into batteries, and are thoroughly tested to all but eliminate the possibility of ignition when a tool is in use. However, tool users should always read the directions and practice safe battery use, which means not overcharging or overheating a battery, not letting the cells get too low, and avoiding extreme weather conditions.

“Outside of power tools, lithium-ion battery safety affects everyone, so everyone needs to be educated,” he adds. “If you’re traveling by plane and have an extra battery for your cell phone, camera, laptop, or if you do happen to be traveling with a power tool, keep those spare batteries in the cabin, rather than checking them with cargo in the belly of the plane. They’ll be much safer that way.”