Posted on 01/18/2013 12:56:33 PM PST by Ron C.
A charred lithium ion battery at the center of the worldwide grounding of the Boeing 787 Dreamliner showed evidence of thermal runaway -- which is indicative of a design problem, experts tell FoxNews.com.
The All Nippon Airways plane made an emergency landing Wednesday morning in western Japan after its pilots smelled something burning and received a cockpit warning of battery problems. Nearly all 50 of the 787s in use around the world have since been grounded.
The batterys burned insides indicate it operated at a voltage above its design limit, a Japanese investigator said Friday. Thats a clear sign of an out-of-control chemical reaction, explained Reginald Tomkins, a professor of chemical engineering at New Jersey Institute of Technology.
(Excerpt) Read more at foxnews.com ...
Thanks much - interesting stuff! Now I wonder if they’ll ever find out what caused it. (Over or under charged?)
So in short this was a starter battery (and a backup breaking battery) - if I read correctly. Sounds like the load for starting is greater than the battery is designed for - if after starting the engines, it has to come into play too soon afterward for breaking. Too much demand for too small a battery perhaps?
You're welcome.
Some good comments in this thread. I enjoy ‘technical discussions’ and learn something every time I do. Ping for more reading later...
“They definitely won’t last the life of the airplane, which is 20-30 years.”
Not if the Lithium battery catches on fire, which was the unspoken punchline.
I think that the point here is that the 787 lifespan is going to be measured in weeks. Hence, these batteries are certainly going to last for the life of the aircraft.
It’s normally not used unless other power sources are not available.
It would be a bit unusual to start the APU or the main engines with the batteries.
It was probably last done when they were testing the planes.
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