Tiny "fibers" may have played role in 787 battery failure, NTSB says

Tue Feb 12, 2013 1:23am EST
 

By Alwyn Scott

SEATTLE (Reuters) - The U.S. National Transportation Safety Board is investigating whether tiny fiber-like formations, known as dendrites, inside lithium-ion batteries could have played a role in battery failures on two Boeing Co (BA.N: Quote) 787 Dreamliners last month.

Dendrites - just one of several possible causes under investigation by the agency - accumulate as a battery is charged and discharged, and can cause short circuits, according to battery experts.

"As part of our continuing investigation, we are looking at whether dendrites may or may not have been a factor," Kelly Nantel, director of public affairs for the NTSB, told Reuters in an email.

The Wall Street Journal reported on Monday that the NTSB was looking into dendrites, suggesting that investigators were looking at the tiny deposits as a major element in the probe.

Nantel said the NTSB has not ruled out any potential causes and that dendrites are "one of many things we are looking at" in determining what caused a battery aboard a parked Japan Airlines (9201.T: Quote) 787 to catch fire in Boston on January 7.

"We are still considering several potential causes for the short circuiting" in the sixth of eight cells in the battery on the JAL plane, Nantel said.

NTSB Chairman Deborah Hersman said last week that a short circuit in the lithium-ion battery had caused the fire.

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The burnt auxiliary power unit battery, removed from an All Nippon Airways' (ANA) Boeing Co 787 Dreamliner plane which made an emergency landing on January 16, 2013 in Takamatsu, is inspected by the manufacturer at the headquarters of GS Yuasa Corp in Kyoto, western Japan, in this handout photo taken on January 26, 2013 and released by the Japan Transport Safety Board (JTSB) February 5, 2013. REUTERS/Japan Transport Safety Board/Handout