Li-ion Burned Batteries: Neutron Test Options?
On Jan 16 J. Barton started communicating with a contact at Boeing Co. to encourage consideration of neutron methods at an early stage, and to provide contacts in USA (NIST) and Japan (JAEA). On Jan 23 J. Barton started toward links with US safety authorities including the Federal Aviation Authority.
Lithium-ion battery is a general term used to describe a variety of chemistries. The Boeing 787 batteries consist of 8 cells arranged in two rows. The case of each cell is stainless steel. Each cell (undamaged) contains 3 rolls formed from flat sheets of anode (Lithium cobalt-oxide), cathode (copper sheet coated with graphite), and separator layer of polymer. There is also electrolyte which contains hydrocarbons.
A detailed report on Li-ion batteries fire hazards (Ref. 1) lists the following possible triggers that could be the root cause of a fire: Thermal Abuse; Mechanical Abuse; Electrical Abuse; Manufacturing Defects.
Subcategories of Electrical abuse include overcharge, external short, over-discharge, poor cell electrochemical design, and internal cell fault related to manufacturing. Subcategories of manufacturing defects could include contamination, poor welds; weld spatters, flaws in electrode coatings, and tears in electrodes or separators.
The manufacturer Boeing of USA subcontracts to Thales of France for the electrical system. Thales subs to GS Yuasa of Japan for the batteries and to Securaplane of USA for the battery chargers. Securaplane, is a subsidiary of a firm Meggitt of Britain.
Incident 1. Japan Airlines 787 Jan 7 2013 Boston Airport USA.
Investigator: US National Transportation Safety Board. (NTSB).
This fire was so severe the fire fighters took over one hour and a half to declare control. On Jan 21 the media reported the battery had regular X-ray and CT scans. Three cells were selected for more detailed radiography. By Jan 23 NTSB reported all 8 cells had varying degrees of thermal damage. Six cells had been scanned and disassembled for further investigation. On Feb 2 the US NTSB announced they still had no evidence to confirm what caused the fires, and they were turning to 10 batteries replaced prematurely by All Nippon Airways and 3 by United Airways to see if any link could be identified between this unusual occurrence and the two burned batteries.
Incident 2 All Nippon Airlines. Jan 16 2013. Emergency landing. Japan.
Investigation spokesman Shigeru Takano, director Japan Ministry Air Transport Safety.
This investigation started 9 days after incident 1 and X-radiography was performed Jan 23 at the Japan Space Agency in Tokyo. Plans announced were to take the battery to the manufacturer, GS Yuasa in Kyoto, for disassembly the week of Jan 28. The Japan Transport Safety Board announced Feb 6 that X-ray CT scans and other analysis found damage to all 8 cells and evidence of thermal runaway but no proof of the root cause. The investigators earlier said they found no evidence of quality problems at the manufacturer’s site, GS Yuasa, Kyoto, Japan.
A. Facts on Li-ion batteries and fire hazards, July 2011 (112 pages).
B. Neutron diagnostics on Li-ion batteries.
 Martin Lanz et al. In situ neutron radiography of lithium-ion batteries during charge/discharge cycling. Journal of Power Sources. 101 (2001) 177-181
 D.Goers et al. In Situ Neutron Radiography of Lithium-ion Batteries: the gas evolution. Journal of Power Sources 130 p.221-226 (2004).
 J.B.Siegal et al. Neutron Imaging of Lithium Concentrate in LFP Pouch Cell Battery. Journal of the Electrochemical Society. 158 A 523 (2011)
 L.G.Butler et al. Neutron imaging of a commercial Li-ion battery during discharge: Application of monochromatic imaging and polychromatic dynamic tomography. Volume 651, Issue 1, 21 Sep. 2011, P 320–328
 J.P. Owejans et al. Direct measurement of lithium transport in graphite electrodes using neutrons Volume 66, 1 April 2012, P. 94–99
 Neeraj Sharma Overcharging a lithium-ion battery: Effect on the LixC6 negative electrode determined by in situ neutron diffraction
 Neeraj Sharma Current-dependent electrode lattice fluctuations and anode phase evolution in a lithium-ion battery investigated by in situ neutron diffraction