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Flyby
User Rank
Silver
Boeing's Woes
Flyby   2/5/2013 4:26:52 PM
NO RATINGS
It seems to me that Lithium Ion battery technology has not reached the maturity that resulted in grounding 30+ aircraft, at millions of dollars a day, regardles of any power to weight benefit. If a car has a fire you can quickly pull over and get out. If an aircraft has a fire in flight what do you do?

At the time the US government certified Boeing's 787 Dreamliners as safe, federal rules barred the type of batteries used to power the airliner's electrical systems from being carried as cargo on passenger planes because of the fire risk.

Boeing appears to have taken gamble and lost. Poor design, poor engineering, poor implementation or.... eventually we will know.

diskguy
User Rank
Silver
Re: Designers without applying knowlege = Danger.
diskguy   2/5/2013 2:49:32 PM
NO RATINGS
Not all lithium batteries require cooling so maybe avoiding heat generating batteries would make this a non issue? 

diskguy
User Rank
Silver
Not all Lithium Batteries need cooling
diskguy   2/5/2013 2:44:43 PM
NO RATINGS
There are several lithium ion chemistries available and the cobalt based battery is well known to be thermally unstable.  Recall computer laptop fires? 

If a 'safe' chemistry had been considered, e.g. manganese based lithium then this would have increased the thermal margin such that cooling is not needed and another failure mode is avoided.  Keep it simple!!

Thinking_J
User Rank
Platinum
Arm chair quarterbacks... ?
Thinking_J   2/5/2013 1:54:30 PM
NO RATINGS
Many thoughtful comments .. and better informed than in most media.

The fact remains..

We are just speculating with limited specific knowledge to the details of the two 787 Dreamliners with damaged batteries. This is a very small sample size to make generalizations with. And, yes, media's love of speculation is likely to hurt the image of anything with Li-ion batteries. And that is unfair.

 

Old US Air force definition of an airplane:

A group of compromises , flying in close formation.

 

l_jhanson
User Rank
Silver
Re: Designers without applying knowlege = Danger.
l_jhanson   2/5/2013 12:41:29 PM
NO RATINGS
A couple of issues I have with the overall reporting of this problem...
First, everyone discribes the battery as Boeing's design... Having worked in aerospace, this part very likely was subcontracted... That does not relieve Boeing of responsibility, but the Boeing engineers I have worked with are excellent aerospace people, maybe not battery people... Therefore the possible outsourcing...

Second, many have freely tossed around the word 'fire'... related to this failure... I know, many of our parents probably stated "where there is smoke, there is fire!" but in reality there isn't always... It is obvious there was significant heat released, and a great amount of smoke... but maybe not flame... My experience with lithium-ion batteries leads me to believe there quite possibly was not flame generated... The batteries have high energy density but unlike gasoline, I have not experienced flame or explosion as a result of failure...

aeroEngr512
User Rank
Iron
Battery-powered cars and Boeing's Li-ion problem
aeroEngr512   2/5/2013 10:29:56 AM
Recent publications on Li batteries indicate that Li-ion batteries have a problem which NiCads do not: The former melt at a very low temperature and once the process starts, it doesn't end until the battery is consumed in a catastrophic meltdown, thus the fires. NiCads, however, require double the weight for the same energy storage, thus the urge to use Li's.

One can readilly extrapolate that the new Li's used on the aircraft are larger than previous models, thus quite possibly creating a temperature gradient from the innermost cells to the outside which is risky in terms of reaching the melting point within the battery. If this be true, two cures are indicated: (1) active cooling of the batteries (not currently provided for in the Boeing design), including possibly active cooling within the battery volume, and temperture sensing within the battery (also apparently not included) as a control signal to the charging circuitry.

Battery powered cars are a product of the man-made global warming theory and taxpayer subsidies. If one believes in the theory, then one should be prepared to have egg on one's face when the theory is finally accepted as a hoax. Quiz: Who was it that said back in 1933 that "if you tell a lie and keep repeating it, the lie will come to be accepted as the truth ... the truth is the mortal enemy of the lie and thus, by extention, the truth is the mortal enemy of the state"? Hint: der Fuerher loved this guy.

naperlou
User Rank
Blogger
Re: Designers without applying knowlege = Danger.
naperlou   2/5/2013 10:02:59 AM
Chuck, it is a wonder that the engineers at Boeing do not seem to have provided enough battery protection, or cooling, is puzzling.  It is puzzling on a couple of levels.  The first is that Boeing is an aerospace company, and that kind of thing is very important in that world.  The second is tha they do not seem to be up on the latest research.  Any reading of the information available from vendors of CAE software, such as Ansys and Comsol, would reveal lots of articles about lithium ion battery research from the major auto companies.  One of the recurrent issues is cooling. 

Don't forget, though, that there was that case of the Chevy Volt that had been used in a crash test caught fire after sitting there for a couple of weeks, if I recall correctly.  You wrote an article mentioning it just about one year ago.  And, of course, there is the celebrated case of the Apple laptop batteries that caught fire.  These are power sources that are very good, but do requre, as many of your readers point out, some very good engineering to use safely.  I use one in my laptop and I am now comfortable using it in my lap.  That, in itself, says something.

Niel
User Rank
Gold
Re: It sucks to be the new kid
Niel   2/5/2013 10:01:56 AM
NO RATINGS
"At one time they put out a broadly repeated story that automobiles were dangerous because driving at more than 17 mph could be harmfull."

I wondered where the UK gov't got the idea 20 mph limits was a good idea!

 

Thanks for that.

eafpres
User Rank
Gold
Re: It sucks to be the new kid
eafpres   2/5/2013 9:56:15 AM
NO RATINGS
I agree with George--there is the factor that Boeing was going to take lumps on this thing, and there will probably be more lumps to come.  Surely they knew that, and they will get past this.  In the meantime, while it should not be surprising the non-technical press gets it wrong or jumps to conclusions to sell airtime or imprints, we should expect more from the engineering community.  What amazes me is that with no analytical results so far (a lot of experts working for weeks) we have so many comments on DN and elsewhere condeming, convicting, villifying, etc. Boeing engineers and/or management.  Now who's rushing to judgment?

Regarding the article, I agree with the author in the sense that this is not an apples to apples situation, so we should not go on an automotive witch hunt.  Yet, given the tiny penetration and production of EVs to date, I would expect more issues with them in the future.  Let's face it, the Automotive industry continues to make mistakes after more decades of experience than the Aviation industry.  Bad tire designs, bad suspension designs, bad electronics, bad material choices (remember all the peeling paint when plastic bumper parts came out?), you name it.  What do all these have in common?  Not enough testing.  Or ignoring results.  Or poorly designed tests, which is amazing for such a mature industry as Automotive.  

So while I prefer not to crucify Boeing, let's not anoint the Automotive Industry with sainthood just yet.

GTOlover
User Rank
Platinum
Re: Designers without applying knowlege = Danger.
GTOlover   2/5/2013 9:47:17 AM
"But the term that too often gets left out of these discussions is "engineering."" This is one of your best lines! We to often (myself included) like to find blame instead of seeking solutions. Then when we find blame, we love to cross-link the resulting mistake to any and all related applications.

As for the modern media, they prostitute themselves on the hyperbolic reality to sell, sell, sell! Investigative reporting is a lost art. Only the stunning or shocking (whether it is true or not) is protrayed. Since only a few 787's were flying, the news must link to a more tangible audience knowledge. Thus, make-up stuff about electric cars and now everyone is clamoring to read the article. Afterall, they need to know if their car is safe!

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