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Electronics & Test

Lithium-Ion Batteries Emerge as Possible Culprit in Dreamliner Incidents

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Paul Murk
User Rank
Bronze
Lithium-Ion Batteries , Second look!
Paul Murk   1/18/2013 10:57:16 AM
At first all the failures may look unrelated due to the fact they all perform different functions on the Airbus.

But before a general comment can be made as in the article, as an engineer, I would investigate the specifications requirements from all these peice parts and check in- fact they have been enviromentaly accepted for high altitude low atmospheric pressure, Vibration of  jet engine frequency and air turbulance of sympathetic oscillations, and extreme temperature changes mostly cold temps.

Now if we take all these into effects, I bet we might find a common thread. It cost $$$ for screens like this and BOEING could have cut cost by using "COTS" of the shelf items.

The Lithium batteries were once not allowed on board plane in laptops because of inherient design issues that caused a possible fire. What has changed with Lithium batteries to make them safe???

Someone in BOEING is an Engineer of poor judgement....Not the structure of the aircraft but selected components not purchased properly for the job is whats at fault.

I bought a Cadillac and the dealer gives me a Chevrolet...get my point

Regards.

bdcst
User Rank
Platinum
Re: What type of lithium ion batteries?
bdcst   1/18/2013 10:42:38 AM
I find it ironic that the 787 uses high capacity Lithium Ion batteries for its standby/startup power when such batteries onboard as cargo have had severe restrictions placed upon them in the past.  For example UPS considers batteries with a watt/hour capacity greater than 20 but less than 100 to be shippable but only when handled as hazardous material.  Anything above 100 Wh is not shippable by air according to UPS.  This for a disconnected, not in service battery!

The IATA bans cargo shipments of primary cell Lithium Metal batteries from all passenger planes.  Obviously, the button cell in your wristwatch is okay as long as it isn't part of a cargo shipment.

The IATA regulation of 100 Wh or less for secondary Lithium Ion batteries has been the limiting factor for available run time for professional video cameras.

 

DJP
User Rank
Silver
Charging system
DJP   1/18/2013 10:18:00 AM
Overcharging is well known to cause overheating. The charging system and overheating protection system need to wwork to prevent this. Apparently this has not been completely effective. I would look carefully at the charging system to see what unusual conditions may exist. Perhaps the intense cold in the exterior environment could trick the charging system into overcharging.

Ken E.
User Rank
Gold
Re: Cooling at 30,000 ft.?
Ken E.   1/18/2013 10:08:16 AM
NO RATINGS
SystemsGuy, my understanding is that this battery came into play only on the ground, i.e. something to do with landing gear controls or something.  So high altitude cold air doesn't help that situation much.

In any case, flight controls probably get their biggest workout getting to altitude or landing, all lower altitude issues, and must be designed for the worst case.

ScotCan
User Rank
Platinum
Re: fired
ScotCan   1/18/2013 9:53:49 AM
Liaison engineers have commented previously that Boeing may have done too much too soon with this aircraft. 

We have had lithium systems problems in E scooters where thermal overload shut down the 48V system via the batteries management software. We concluded that heavy current draw during acceleration was causing the problem and tried conditioning that by tweaking the controller 

Charles Murray
User Rank
Blogger
Re: What type of lithium ion batteries?
Charles Murray   1/18/2013 9:53:22 AM
Very good point, davemiga. I've heard -- unofficially -- that it was cobalt, but haven't been able to verify it. And, yes, a cobalt chemistry is slightly more susceptible to overheating, although all lithium-ion chemistries are on the edge (with the possible exception of the so-called "nanophophate" chemistries).

davemiga
User Rank
Iron
What type of lithium ion batteries?
davemiga   1/18/2013 9:47:51 AM
The description of the meltdown seems that they might be using lithium cobalt, not a good design choice if that is the case. Lithium iron phosphate LiFeP04 would be the only safe choice. Anyone know what Boeing used?

ChasChas
User Rank
Gold
Re: Dreamliner Batteries
ChasChas   1/18/2013 9:44:45 AM
I look at that tight battery box and think - you cannot cool an adiabatic heat source with it's own energy - inside of the system.

SystemsGuy
User Rank
Iron
Cooling at 30,000 ft.?
SystemsGuy   1/18/2013 9:39:44 AM
NO RATINGS
How hard can it be to cool batteries when the outside temperature at 30,000 ft is below (-60F) ?

gafisher
User Rank
Gold
Re: Dreamliner Batteries
gafisher   1/18/2013 9:39:12 AM
Lithium-Ion chemistry is also used in the Chevy Volt, the Fisker and other electric vehicles (but notably not in the Toyota Prius).  Li-ion is a very energetic chemistry, which is necessary to pack so much energy in a limited volume.  Gasoline is even more efficient, so much so that it can explode in situations where Li-ion batteries would only burn.

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