Smaller-scale lithium-ion batteries have been used for more than 20 years to power laptops and other electronics. They are also increasingly popular in electric cars.
Following are some key facts about the batteries used on board the 787, and the lithium-ion battery technology, which allows batteries to be lighter and store far more energy.
- Boeing's new 787 airliner uses two lithium-ion batteries made by the Japanese company GS Yuasa Corp, with the associated control circuits made by Thales SA. They are part of an auxiliary power unit supplied by UTC Aerospace, a unit of United Technologies Corp, that provides power while the airplane is on the ground.
- The F-35 Joint Strike Fighter, built by Lockheed Martin Corp, uses a similar lithium-ion battery but it is built by a different manufacturer, France's Saft Groupe SA. Lockheed said it did not expect any impact on the Pentagon's largest weapons program from the Boeing grounding since the batteries were built by a different company.
- The Airbus A350 airliner built by Europe's EADS is also due to use a lithium-ion battery made by Saft. That plane is due for its first flight this year.
- Several other aircraft, including the Airbus A380 and Boeing's 787, use smaller lithium batteries for emergency lighting and other purposes.
- Lithium-ion batteries can catch fire if they are overcharged, and once alight they are difficult to extinguish because the chemicals produce oxygen. But Boeing said it designed multiple systems to prevent overcharging, contain a battery fire and siphon smoke away before it reaches the cabin.
- Boeing said the battery it uses on the 787 is about twice as large as a car battery and has been extensively tested, both in the lab and in operation. The U.S. National Transportation Safety Board said the auxiliary power unit battery that caught fire on January 7 at Boston's Logan International Airport weighed about 63 pounds and measured 19 inches by 13 inches by 10.2 inches.
- Similar batteries are used in the Chevrolet Volt hybrid electric car built by General Motors Co and other electric cars, satellites, laptops, cell phones and other electronics. The technology was first used in electronics by Japan's Sony Corp in 1991.
- Lithium-ion batteries can be made lighter, smaller and in a way that retains capacity longer. Lithium-ion batteries are about half the weight of nickel-metal hydride batteries, but their energy content is nearly twice as high.
- Problems can occur with the lithium-ion batteries, which contain flammable chemicals, if a short-circuit occurs, if they are overcharged, or if they are put under too much pressure, said Daniel Doughty, a former U.S. government researcher and expert on battery safety.
- Battery failures can incubate for a long time before becoming noticeable, Doughty said, citing a 2011 case in which a lithium-ion battery pack in a Volt caught fire three weeks after U.S. safety regulators conducted a crash test. The National Highway Traffic Safety Administration later determined the Volt and other electric vehicles posed no greater risk for fire than gasoline-powered vehicles.
- Another lithium-ion battery maker, A123 Systems, was forced to recall battery packs made for Fisker Automotive's plug-in hybrid sports car, the Karma, last year. A123, which ultimately went bankrupt, blamed a manufacturing defect for the batteries' problems.
- EaglePicher Inc, a unit of OM Group Inc, also makes a lithium-ion battery that is currently being certified for a business jet, according to a research note by Buckingham Research Group. It quoted company executives as saying they could have a 787 battery designed and certified in 12 to 15 months.
(Reporting By Andrea Shalal-Esa in Washington, Tim Hepher in Paris, Alwyn Scott in Seattle and Deepa Seetharaman in Detroit)