Ougassing should have been observed during tests. True, low atmospheric pressure might accelerate outgassing but the atmospheric pressure inside a (pressurized) commercial aircraft cabin is generally in the range of normal.
I also think vibration could be the culprit. (see my comment, above).
That's a scary thought, Bill. It's not hard to imagine Boeing deliberately choosing cobalt oxide for the higher energy density. That's its chief advantage over other lithium-ion chemistries and it's the reason many engineers choose that chemistry. But as for their alleged lack of a cooling system: It's anybody's guess. I think a lot of engineers are still climbing the learning curve when it comes to all the lithium-ion chemistries.
I can't believe Boeing would use a battery design that was not so carefully bench tested that there was absolutely no way it could overheat no matter what happened to the charging circuit and no matter how little cooling was available.
On the other hand it is quite possible that due to vibration in the aircraft, the electrodes might go into a vibrational resonance allowing a couple to touch each other and cause an internal short. This could be difficult - but not impossible - to simulate on the bench.
Very good point, Paul. Elton Cairns of the University of California agrees with you. He told us that the higher, colder altitudes were a detriment, not an advantage in this situation. Cairns, by the way, should know: He designed the PEM fuel cells for the Gemini spaceflights in the 1960s.
Given the importance of this issue to Boeing, I would be shocked if it kept the 787 down until 2014. That would be a major setback to a very high profile program. But I also think their engineers will also be very careful in avoiding missteps in implementing a solution to this problem. Not an easy thing to have the world watching while you solve a complex technical issue.
They will get it right eventually, Liz. But it could take a while. Over the weekend, CNET published a story in which they, too, interviewed Donald Sadoway of MIT. Sadoway told them that the problems could keep the 787 fleet grounded until 2014.
If this is true, then it's a bit scary to think this could happen again. Let's hope engineers get the battery chemistry right next time so something like this doesn't happen again and cause an even more dangerous situation.
Wal-Mart will hold its second Made in the USA Open Call July 7-8, at its headquarters in Bentonville, Ark. The event will be a repeat effort by the world’s biggest seller of consumer goods to increase the amount of US-made products it sells in Wal-Mart stores, in Sam’s Club members-only wholesale outlets, and on walmart.com.
From design feasibility, to development, to production, having the right information to make good decisions can ultimately keep a product from failing validation. The key is highly focused information that doesn’t come from conventional, statistics-based tests but from accelerated stress testing.
There’s a good chance that a few of the things mentioned here won't fully come to fruition in 2015 but rather much later down the line. However, as Malcolm X once said, "The future belongs to those who prepare for it today."
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.