WASHINGTON - Lithium-ion batteries like the ones that overheated on two Boeing 787 Dreamliners can be made safe enough for even the most critical transportation uses, according to experts who spoke at a National Transportation Safety Board forum Thursday.

"Safety is improving year on year for this technology," said Dan Doughty of Battery Safety Consulting Inc. in Albuquerque.

The question is whether safeguards, such as extensive testing and building in protective circuitry, are too costly, said Vince Visco, senior vice president of strategy and business development at Quallion. Los Angeles-based Quallion makes batteries for use in space and medical devices.

Boeing is proposing protections that include some of those Visco described in its redesigned battery, including titanium vents to draw smoke and fumes outside if a fire starts, as a way to get its grounded planes airborne. The Federal Aviation Administration hasn't said when it will act on Boeing's proposed fix.

The safety board, as part of an investigation into a 787 battery fire Jan. 7 in Boston, held Thursday's forum to hear from academic, industry and government officials on how to make cells safer. It will hold a separate hearing April 23-24 to examine the Dreamliner's battery design and how it was certified by the FAA.

Rechargeable lithium cells, which power devices ranging from Apple Inc.'s iPad to power tools, are increasingly being used in transportation equipment because they are lighter and hold more power than other battery technologies, said NTSB Chairman Debbie Hersman.

"Yet lithium-ion batteries, like other power sources, such as the gasoline that powers so many personal vehicles, come with risks," Hersman said. "These batteries are designed to produce energy - it is their very nature that poses the greatest risk."

Visco declined in an interview to say whether Boeing's plan is sufficient to ensure safety on the plane. Adopting new protections will bring the 787's battery pack, which was designed almost a decade ago, to more current standards, he said.

The plane, Boeing's newest airliner, has been grounded since Jan. 16 following two incidents in which on board lithium battery packs smoldered.

When they catch fire, lithium-based batteries may burn violently, spewing flammable gas and molten metal. However, batteries much larger than those on the 787 have proved themselves in recent years in uses that include hybrid buses and in power grids, said Yet-Ming Chiang, an MIT professor who also spoke at Thursday's forum.

The industry increasingly understands the ways that batteries fail, which include internal short-circuits, overheating, manufacturing defects and damage during use, Chiang said.

"All of the major manufacturers try to test and plan for those failure modes," he said in an interview.

NASA, which has used lithium-based batteries on manned space missions since 1999, performs extensive testing on each cell and takes steps to limit the chances of fire, said Judith Jeevarajan, the agency lead for battery safety.

Other steps, such as never fully charging a battery, limit the amount of heat discharged if a battery fails, she said.

"There is no reason to say that lithium-ion won't have a place in high-consequence applications, such as passenger airplanes," said Doughty, a former head of battery testing at Sandia National Laboratories.

The FAA has recorded 33 cases of batteries brought aboard commercial planes by passengers or as cargo catching fire since 2009. Of those cases, 26 involved lithium-based batteries, according to the agency.


Tucson-based Securaplane Technologies, at its Oro Valley plant, helps make the lithium-ion batteries for the Boeing 787 Dreamliners.