NTSB's press release (1/20/2013; emphasis is mine):
NTSB Provides Third Investigative Update on Boeing 787 Battery Fire in Boston
January 20
WASHINGTON - The National Transportation Safety Board today released a third update on its investigation into the Jan. 7 fire aboard a Japan Airlines Boeing 787 at Logan International Airport in Boston.
The lithium-ion battery that powered the auxiliary power unit has been examined in the NTSB Materials Laboratory in Washington. The battery was x-rayed and CT scans were generated of the assembled battery. The investigative team has disassembled the APU battery into its eight individual cells for detailed examination and documentation. Three of the cells were selected for more detailed radiographic examination to view the interior of the cells prior to their disassembly. These cells are in the process now of being disassembled and the cell's internal components are being examined and documented.
Investigators have also examined several other components removed from the airplane, including wire bundles and battery management circuit boards. The team has developed test plans for the various components removed from the aircraft, including the battery management unit (for the APU battery), the APU controller, the battery charger and the start power unit. On Tuesday, the group will convene in Arizona to test and examine the battery charger and download nonvolatile memory from the APU controller. Several other components have been sent for download or examination to Boeing’s facility in Seattle and manufacturer’s facilities in Japan.
Finally, examination of the flight recorder data from the JAL B-787 airplane indicate that the APU battery did not exceed its designed voltage of 32 volts.
In accordance with international investigative treaties, the Japan Transport Safety Board and French Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile have appointed accredited representatives to this investigation. Similarly, the NTSB has assigned an accredited representative to assist with the JTSB’s investigation of the Jan. 15 battery incident involving an All Nippon Airways B-787. Both investigations remain ongoing.
Further investigative updates on the JAL B-787 incident will be issued as events warrant. To be alerted to any updates or developments, please follow the NTSB on Twitter at www.twitter.com/ntsb.
NTSB Media Contact:
Office of Public Affairs
490 L'Enfant Plaza, SW
Washington, DC 20594
(202) 314-6100
Kelly Nantel
kelly.nantel@ntsb.gov
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5 comments:
They not even able to get fairly simple lithium battery to work properly but people optimistically and stubbornly dreaming about safe Thorium reactor in near future.
Any comments yet about the quality of the battery? Any comments on how sensitive Lithium is to radiation..think is it very sensitive..
No over voltage seem to point to and internal short due to slightly unequal cell voltage this is known as an unbalanced battery pack.
"The need for balancing:
The continued use of unbalanced cells will lead to one or more of them becoming overcharged and/or over-discharged with each cycle. This is the reason why a battery that has previously performed apparently faultlessly 'suddenly' catches fire. If you have a well-used battery that has never been maintained you are strongly advised to stop using it and have it checked to ensure that the cells are in a balanced condition."
http://www.modelflight.regheath.com/mf109/airspaceset.htm
@3:51
As for radiation adversely effecting lithium ion chemistry nothing could be further from the truth lithium ion batteries are used in spacecraft.
"Planetary exploration missions to Jupiter and its moons require that the power system components, including batteries, be tolerant to high intensities, about 4 Mrad, of γ-radiation. In view of the several polymeric materials used as separators and binders and the use of organic electrolyte solutions in Li-ion cells, it is difficult to predict their response to such radiation environments. Therefore, a detailed experimental evaluation was undertaken to determine the performance of Li-ion cells after exposure to various levels of cumulative radiation levels up to 25 Mrad, at different levels of intensities. Prototype cells, obtained from two domestic sources for aerospace lithium-ion batteries and consisting of two different chemistries, were used as test articles. Discharge performances, at ambient and low temperatures, as well as, electrical impedance spectroscopy responses were determined after each exposure, and analyses were made for the impedance characteristics and their changes upon irradiation. Postradiation cycling tests were carried out on these cells to assess their cyclability subsequent to radiation exposure. Although control measurements were not made on cells without radiation, these studies reveal that the lithium-ion cells display good tolerance to radiation, with only marginal decline in their capacity, and with no significant change in capacity fade rate during subsequent cycling."
http://jes.ecsdl.org/content/151/4/A652.abstract
Anon at 3:51PM, what radiation? From long-distance flights, I assume? If you are insinuating the radiation from Fukushima fallout, that's baseless. Yuasa's factory is in Kyoto Prefecture, where the fallout was negligible.
Contrary to popular belief particularly outside Japan, regions west of Shizuoka are hardly contaminated from the Fukushima fallout.
I amazed BA selected to go with lithium melting at 357F versus 2,800F for nickel. With nickel batteries the plane could catch fire and being fallout out the sky and still function. Lithium battery packs need an eject button for when they heat up to keep the plane clear of toxic fumes.
Seems a temperature probe(s) would be a must.
BA answer to a lithium fire was halogen extinguishers and ports for smoke directly tooutside the skin of the plane.
From Wiki and I'd like it to stay this way (few accidents) with any plane...There are, on average, 1,250 Boeing 737s airborne at any given time, with two departing or landing somewhere every five seconds.
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