NEW YORK — Powerful and lightweight, lithium-ion batteries are the perfect power source for modern gadgets. But ubiquitous as they are, their short history has also been fraught with problems. They have caught fire in cellphones, laptop computers, and electric cars, and have even destroyed a small Navy submarine.
Now, federal investigators are trying to determine why a lithium-ion battery caught fire in Boeing’s long-awaited 787 Dreamliner last week, and they have grounded the planes until they figure it out.
While Boeing officials insist the failure never endangered passengers or the plane’s integrity, the prospect that batteries would leak flammable fluids and smoke on flights packed with passengers has opened perhaps the most unnerving chapter in the technology’s relatively short life.
For Boeing, the development of the 787 represented a push into new technology and energy efficiency, and the company staked much of its future on the plane. It turned to the new batteries for many of the same reasons that Silicon Valley and Detroit have: They pack a lot of energy in a small package and, unlike older batteries, can be charged rapidly and frequently without loss of power.
Even though the safety standards are higher in aviation than in most other industries, federal regulators decided in 2007 to approve Boeing’s use of lithium-ion batteries for the first time in one of its passenger jets.
It is still not clear what caused the battery fire last week in Boston, about 30 minutes after a Japan Airlines 787 landed from Tokyo and passengers had gotten off the plane. The cleaning crew noticed smoke seeping into the cabin, and it took firefighters 40 minutes to put out the battery fire in the electrical bay in the back of the plane.
On Wednesday, a 787 had to make an emergency landing in Japan after pilots received a smoke alarm. Officials found that a battery in the front of the plane was charred and swollen. Chemicals appeared to have leaked, and discolorations on the plane suggested that there had been smoke inside.
Investigators are considering a variety of causes, though it might be months before they pinpoint what went wrong and how to solve it. The problem could be in the basic design of the batteries, the units that charge them, or in an undetected manufacturing flaw, specialists said.
Boeing officials said they felt they understood the potential hazards in the batteries, and they built a system with multiple layers of protection that they said would keep them from overheating and would contain any problem.
Boeing and the FAA now realize the heat was so intense that it appeared to burn through the battery containers.
Still, even former safety officials who have frequently criticized the FAA say that as the 787 paves the way for airplanes to be more fuel-efficient, it made sense for Boeing to shift to the latest battery technology.
‘‘It was a bit of a judgment call,’’ said John Goglia, a former member of the National Transportation Safety Board. ‘‘But I think I would have gone with the new technology myself, because you don’t make any advances if you stay with the same old equipment.’’