Author Topic: Boeing 787 Li-Ion Meltdown  (Read 64118 times)

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Offline phil_jp1

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Re: Boeing 787 Li-Ion Meltdown
« Reply #100 on: January 30, 2013, 10:39:11 am »
Elon Musk - the founder of Tesla and SpaceX pointed out that the design itself is a complete crap. They've used 8 huge cells, that are not separated from each other in any reasonable way to prevent thermal runaway.
Here's the article:
http://www.flightglobal.com/news/articles/elon-musk-boeing-787-battery-fundamentally-unsafe-381627/
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Offline TerraHertz

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Re: Boeing 787 Li-Ion Meltdown
« Reply #101 on: February 01, 2013, 05:46:09 am »
http://www.flightglobal.com/news/articles/ntsb-finds-signs-of-short-circuit-thermal-runaway-in-jal-787-battery-failure-381464/
NTSB finds signs of short circuit, thermal runaway in JAL 787 battery failure

http://finance.yahoo.com/news/japanese-airlines-had-dreamliner-battery-062501475.html
Japanese airlines had 787 battery issues before recent incidents

Neither of these articles is any kind of surprise.

This all feels like watching a slo-mo trainwreck.
Prediction: the 787s are never going to be permitted to fly again until Boeing has completely replaced these battery units with a new, much safer design.
How long will that take? Considering Boeing was already in financial trouble due to the late delivery of the 787, this doesn't look good for them.
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Offline r90s

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Re: Boeing 787 Li-Ion Meltdown
« Reply #102 on: February 01, 2013, 03:01:22 pm »
I don't know, but Boeing has 13,ooo,ooo,ooo sitting in the bank at the moment....
« Last Edit: February 01, 2013, 03:39:01 pm by r90s »
 

Offline jerry507

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Re: Boeing 787 Li-Ion Meltdown
« Reply #103 on: February 01, 2013, 03:35:44 pm »
That's a really pessimistic view. It's absolutely too early to tell if the culprit is the battery design or some other external (to the battery) factor. They'll figure it out and fix it, and hopefully redesign the battery at their leisure to a safer design.

It's a 1 in a million chance that they move away from lithium ions. First, they don't have to and second, it would cost far too much money to.
 

Offline ErikTheNorwegian

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Re: Boeing 787 Li-Ion Meltdown
« Reply #104 on: February 01, 2013, 08:28:48 pm »
Elector Elabs

has started its own "The Dreamliner Project" for fixing the problem:

http://www.elektor-projects.com/9130102823
/Erik
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Offline mikeselectricstuff

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Re: Boeing 787 Li-Ion Meltdown
« Reply #105 on: February 01, 2013, 11:22:24 pm »
Quote
It's absolutely too early to tell if the culprit is the battery design or some other external (to the battery) factor.
If any reasonable (i.e. non-crash) external factor can make a battery do that, then the fault is with the battery module (including its management electronics).
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Offline r90s

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Offline Lawsen

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Re: Boeing 787 Li-Ion Meltdown
« Reply #107 on: February 02, 2013, 02:37:10 am »
Elon Musk, the founder of Pay Pay, Space X, and Tesla Motors, have an opinion about the spacing between LiCoOxide cell spacing for cooling:

http://www.dailytech.com/article.aspx?newsid=29781
 

Offline Obi_Kwiet

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Re: Boeing 787 Li-Ion Meltdown
« Reply #108 on: February 02, 2013, 02:48:01 am »
http://www.flightglobal.com/news/articles/ntsb-finds-signs-of-short-circuit-thermal-runaway-in-jal-787-battery-failure-381464/
NTSB finds signs of short circuit, thermal runaway in JAL 787 battery failure

http://finance.yahoo.com/news/japanese-airlines-had-dreamliner-battery-062501475.html
Japanese airlines had 787 battery issues before recent incidents

Neither of these articles is any kind of surprise.

This all feels like watching a slo-mo trainwreck.
Prediction: the 787s are never going to be permitted to fly again until Boeing has completely replaced these battery units with a new, much safer design.
How long will that take? Considering Boeing was already in financial trouble due to the late delivery of the 787, this doesn't look good for them.

A battery pack like this is peanuts compared to the image loss. I would guess that they are having a firm doing an expedited redesign on this and will be replacing them all at shortly. There's too much money at sake for such a trivial part.
 

Offline EEVblog

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Re: Boeing 787 Li-Ion Meltdown
« Reply #109 on: February 02, 2013, 04:54:54 am »
A battery pack like this is peanuts compared to the image loss. I would guess that they are having a firm doing an expedited redesign on this and will be replacing them all at shortly. There's too much money at sake for such a trivial part.

They might have 2 or 3 companies working on it. Whoever delivers and passes certification first, wins. They could afford to spend $1M a day on this...

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Offline JoeyP

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Re: Boeing 787 Li-Ion Meltdown
« Reply #110 on: February 02, 2013, 07:18:46 am »
I have no doubt that Boeing is working at lighting speed to solve the problem. But unfortunately, once they solve it, getting FAA certification for the changes will be more like wading through a tar pit.
 

Online BravoV

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Re: Boeing 787 Li-Ion Meltdown
« Reply #111 on: February 02, 2013, 07:46:53 am »
A battery pack like this is peanuts compared to the image loss. I would guess that they are having a firm doing an expedited redesign on this and will be replacing them all at shortly. There's too much money at sake for such a trivial part.

Image loss, late delivery (probably with penalty/fine), canceled orders/purchases, high chance of losing to competitor while in beauty contest period, large unknown potential cost overhead ... etc. Big headache.  :palm:

For sure fellows at Airbus are smiling a lot lately at work, especially the marketing team.  >:D

Offline r90s

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Re: Boeing 787 Li-Ion Meltdown
« Reply #112 on: February 02, 2013, 11:21:20 am »
for sure fellows at Airbus are smiling a lot lately at work, especially the marketing team.  >:D


Yes, and it seems Airbus has turned off the automated fly into the ground function for now. :-\
« Last Edit: February 19, 2013, 10:27:56 am by r90s »
 

Offline TerraHertz

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Re: Boeing 787 Li-Ion Meltdown
« Reply #113 on: February 02, 2013, 12:30:56 pm »
They might have 2 or 3 companies working on it. Whoever delivers and passes certification first, wins. They could afford to spend $1M a day on this...

Question is, have they created a set of design constraints that  intrinsically has no safe solution?
Whatever replaces the existing packs will have to fit in the same space. I recall seeing a photo of where one of the packs sit, and there doesn't appear to be much free space around it.
If Boeing asked for a pack that could deliver X amount of Amp-hours at a given current, they presumably actually needed that, for aircraft functional reasons.
What if there's no safe way, using any existing battery technology, to pack that much energy into the available  space?
E Musk pointed out that lithium battery systems *must* have sufficient space and thermal insulation between the individual cells, so there can't be a failure cascade.
It looks to me like that extra space maybe isn't available in the Boeing design criteria.


Hmmm...
One possible workaround might be to have the cells immersed in a sacrificial fluid, that would boil off around a cell that was self-immolating. Let the evaporated fluid vent via a burst diaphragm to outside the plane.

But somehow I think the safety agencies wouldn't feel good about any 'solution' which admits cells are going to just unpredictably blow up now and then.
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Online NiHaoMike

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Re: Boeing 787 Li-Ion Meltdown
« Reply #114 on: February 02, 2013, 02:22:21 pm »
What about flat heat pipes between the cells and a small radiator on the outside of the enclosure?
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Online BravoV

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Re: Boeing 787 Li-Ion Meltdown
« Reply #115 on: February 02, 2013, 02:50:20 pm »
What about flat heat pipes between the cells and a small radiator on the outside of the enclosure?

What if the outside of the enclosure where it dumped the heat is not allowed to be heated or no more free space for extruded cooling fins.

Offline bfritz

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Re: Boeing 787 Li-Ion Meltdown
« Reply #116 on: February 11, 2013, 06:36:47 pm »
Boeing Aerospace, back when they supplied everything that went on the space shuttle 
(I had many friends that worked there,) would not allow Li ion on board the shuttle.

Well, if anyone can fix it, it will be Boeing.


This is correct in that Li-Ion was not used, but incorrect as to why.  For example, the MMU's use Lithium Thionyl Chloride, which is a metallic lithium battery, and hence much more problematic should a high temperature condition occur.  These cells were used because of their very high energy density, in spite of their being more problematic than other chemistries.  I know this, as I discussed this choice with the NASA engineers who made the choice.
 

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Re: Boeing 787 Li-Ion Meltdown
« Reply #117 on: February 13, 2013, 09:37:22 am »
There has been an extensive press conference by the NTSB disclosing their findings so far.

CT scans of the batteries, short circuits, thermal runaway etc.

 

Offline r90s

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Offline T4P

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Re: Boeing 787 Li-Ion Meltdown
« Reply #119 on: February 14, 2013, 06:08:56 pm »
I wonder if they considered NiMH, which is a much more stable and safer chemistry. Much reduced hazard with NiMH. Compromise of course here is poorer energy density, so more weight. But I don't know how significant that is.
And then there's another problem. High internal resistance, NiMH are absolute buggers for this. As well as limited ampacity it can take a long time to charge a BIG NiMH

Ram Air Jets are hella tiny, they just barely generate enough power to power a modern pitcock's basic instruments
Once you've seen one i don't think you want to see it again, i'll bet it probably has about several 100s of watts generating power only
 

Online NiHaoMike

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Re: Boeing 787 Li-Ion Meltdown
« Reply #120 on: February 14, 2013, 06:36:12 pm »
I wonder if they considered NiMH, which is a much more stable and safer chemistry. Much reduced hazard with NiMH. Compromise of course here is poorer energy density, so more weight. But I don't know how significant that is.
And then there's another problem. High internal resistance, NiMH are absolute buggers for this. As well as limited ampacity it can take a long time to charge a BIG NiMH
NiMH has been used in hybrid cars for over 10 years now. 10C charge and discharge rates (in the middle of the SOC range) are not uncommon. As for weight, going to NiMH would add about 200lbs total, or less than 1lb per passenger equivalent, certainly not significant enough to matter. (If it did, airlines should charge by weight!)

Or they could go with LiFePO4 which would add even less weight, as in just one passenger being as skinny as Tiffany Yep (rather than being "average American" weight) would more than offset the difference!
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Offline jerry507

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Re: Boeing 787 Li-Ion Meltdown
« Reply #121 on: February 14, 2013, 08:04:16 pm »
And yet you see hybrid cars moving towards lithium ion technologies too :) Lower weight is lower weight.

And as I noted earlier, the ram air turbines can't be THAT tiny. Given that the entire aircraft is fly by wire, it would need to power the main hydraulic systems and enough instruments to allow control of the aircraft. Looking at the diagram posted earlier in this thread, that's 230VAC at some pretty high amperage.
 

Online NiHaoMike

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Re: Boeing 787 Li-Ion Meltdown
« Reply #122 on: February 15, 2013, 01:03:33 am »
And yet you see hybrid cars moving towards lithium ion technologies too :) Lower weight is lower weight.

And as I noted earlier, the ram air turbines can't be THAT tiny. Given that the entire aircraft is fly by wire, it would need to power the main hydraulic systems and enough instruments to allow control of the aircraft. Looking at the diagram posted earlier in this thread, that's 230VAC at some pretty high amperage.
It makes sense when the weight is significant compared to the total weight of the vehicle. Most Lithium batteries in cars are Lithium Iron Phosphate or Lithium Manganese as opposed to Lithium Cobalt anyways.

On the 787, the batteries make up a very tiny percentage of the total weight. If that tiny bit of weight is that significant, the variances in passenger weight would be even more significant.
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Offline Rick Law

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Re: Boeing 787 Li-Ion Meltdown
« Reply #123 on: February 15, 2013, 04:12:07 am »
One answer to your question is that nowadays accountants make some design decisions, and the decisions are based on price, reliability and risk while engineers would think reliability, price and risk.

Hate to tell you, the "nowadays" started well over 40+ years ago.  Think Ford Pinto (and others like it).  The Pinto has a habit of bursting into flames after a small back-end accident.  The lack of gas tank protection was one of deliberate choices (cuts) made to keep the price of the car under a dollar a pound.

Ralph Nader made his name writing the book "Unsafe at any Speed" about yet another car: the Chevrolet Corvair 50+ years ago.

Perhaps if we look back even as far back as the Romans, they might have said "... nowadays, the fight look so fake ..." as the gladiator bleed to death.  At times, we think the past was somehow better.  Perhaps we simply do not look at the good side of nowadays enough; or perhaps the past was really was better...  I will leave that to you to contemplate over.
 

Offline Bored@Work

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Re: Boeing 787 Li-Ion Meltdown
« Reply #124 on: February 15, 2013, 05:05:12 am »
Can't vouche for the Romans. All that's left of them here are piles of rubble and the occasional landmark.

What I see in my industry is that everything has to go faster. Having a year or even two to develop something is almost becoming a luxury.
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