The original intent for the lithium batteries was that for a given capacity, they were a lot lighter than the NiMH ones in use at that point. By the time the protective enclosure was added, the weight advantage was lost. I saw somewhere that Airbus was looking at lithium batteries but hadn't committed to them by the time Boeing had the problem and therefore stuck with the NiMH for now. The technology needs to improve a bit.

Battery size is another consideration, and in that sense they've not lost out enormously. I'm not familiar with the 787 or how big alternative NiMH batteries would have been... Lithium ion batteries are lightweight and compact, and it's their compactness that makes them attractive in mobile phones.

In the grand scheme of things I'd have thought the added weight is pretty small beer

The new stuff will never work
 

Long before the interweb got going I was involved with the introduction to service of the Airbus A320.

As with all new aircraft problems happened and they had to be resolved, rumours abounded about the C of A being withdrawn and all kinds of problems that would cost £££££€€€€€€€$$$$$$$$ to fix.

I see a lot of parallels with what was said in the industry about the A320 back then and the B787 now, the only difference is one of communication now with a few taps of the keyboard rubbish from the uninformed can travel the world as conjecture to be built on by others who rehash it fact.

One only has to see the utter rubbish written on the thread about the B787 that was repaired by Boeing at LHR following a fire.

The fact of the matter is that if the keyboard experts had the internet available during the introduction of the A320 they would have been telling us that the A320 would fail and be consigned to history as an interesting fly by wire footnote following the closure of the production line with twenty or so units being built.

A320
 

Boeing got a waiver on the Li battery by rewriting the Federal register with the FAA. It was titled "special considerations". These requirements were quite stringent, and I think Boeing was over confident. Boeing certified that the battery would not cause an "on board fire" in one billion flight hours. As it happens, there were three fires in less than one hundred thousand hours of fleet time.

To be exact, no "on board fire" did happen, nothing outside the battery casing was burning, the fire was limited to the component and did not spread.
So although not at all a desirable situation, it is not yet proven that this battery fire was indeed a major thread to the safety of the aircraft. However, it is now an even lower risk as it will for sure always be contained...

Actually it is called "special condition", and this is an usual tool during certification of a design which is newer than the rules. When fly-by-wire was introduced for example, it was covered by the same procedures.

"So although not at all a desirable situation, it is not yet proven that this battery fire was indeed a major thread to the safety of the aircraft. However, it is now an even lower risk as it will for sure always be contained..."

So, we are awaiting "proof" that it is a major threat? Hmmm...... I think this system failed to meet the required conditions. Does it now? Have the conditions been altered to allow what was once prohibited? I think the text required no over pressure, no high temps? The over pressure resulted in a burst that did damage to the bay, and that now requires a special steel case? Temperatures were found to be as high as the melting point of stainless steel? I have asked before, do you know if the battery itself has been redesigned?

The Battery yes, the cells inside no. The parameters for charging (max current, max voltage...) and disconnecting it (due to low voltage, avoiding deep-discharge) have been modified, as far as I know the temperature limits as well, quality control has been approved, cells are now separated by fireproof spacers etc.
It obviousy did help but nobody knows which measures did the trick...

Yes it did, but it is "allowed" to do so with a certain (low!) probability, as long as you do not risc a catastrophic loss of the aircraft. Is is not clear (and probably never will) what would have happened, if they would have continued flying (e.g. because they were in the middle of the atlantic). Maybe the fire would not have spread, only the battery may have burned out. A major event, but not a catastrophic one.

I don't think one fire (or 'n' fires) proves that every battery fire will "always be contained".

to be fair, the techs already fine, the issue with the 787 was the design/implementation.

Tesla probably have the most experience in large, high load/density Li battery systems and they have stuck with multiple small cells vs. large single cells (ala the 787)

take a look at their power pack setup:

https://www.tesla.com/en_GB/powerpack

multiple small modules made up from multiple cells, all water cooled.

The 787 battery is also multi-cell (there are 8 cells per battery).

On the original design, a cell failure could propagate to other cells (known as "thermal runaway") and cause very high temperatures / risk of fire.

On the redesigned batteries, the cells are now spaced and lined with ceramic insulation to prevent thermal runaway. The battery charging system was also modified. And then the firebox was added as an additional layer of defense.

We still don't know why the cells failed. It's hard to redesign something when you don't know what may be wrong with the previous design. And for all we know the root cause might have been manufacturing defects, not design defects.

that's what I am getting at, 8 LARGE cells vs. several hundred small cells.

Large cells are always a risk, yes, they are cheaper, however, heat management is much harder along with monitoring, manufacturing QA etc etc.

for example, Tesla use some 7,000+ 18650 cells in the 100Kwh battery for the model S/X.

they use these same cells in 'packs' for the powerpacks, then mount many packs together into one enclosure.

Yet 18650 cells catch fire all the time. There's no evidence that they are any safer / better at handling thermal runaway.

Uncontained Tesla battery fire in Norway due to short circuit:

http://d2odvx3v4cbpyu.cloudfront.net...age-Norway.jpg

There was a second incident in France this summer. The car was burnt to a crisp.

The 787 batteries did a far better job in damage containment.

So, you can only find two cases of battery fire's in over 150,000 examples.

the detail on the two:

Tesla Identifies Cause for Model S Fire in Norway

https://electrek.co/2016/09/09/tesla...d-human-robot/

vs. how many 787 battery fires?

The battery discussion belongs in Tech Log.
Was the smoke in this BA incident battery related?

From a google pop-up ad targeting investors:

"New interest has been sparked in the lithium battery industry, and everybody wants a piece"

and :

"Lithium is set to explode"

I kid you not !

Yet the Tesla design does not prevent hazards Model S fatal Indianapolis crash with battery cells exploding

and

http://insideevs.com/tesla-model-s-f...-pack-related/

:confused:"The battery discussion belongs in Tech Log.
Was the smoke in this BA incident battery related?"

To be fair, is this incident of smoke due the APU battery circuitry? If not, this discussion may be a bit unfair to Boeing.....:confused:

Now posted for the third time in less than two pages :ugh:

So, in summary:
The 787 Li battery was certified to an FAA "Special Condition" and an EASA CRI (Certification Review Item) - a common process when new technology is not covered by the existing regulations
There were two serious 787 battery incidents shortly after EIS - obviously something was missed in the original design/implementation.
Although they were unsuccessful in determining root cause, they brainstormed every possible cause they could come up with and addressed them with a redesign of the battery and associated aircraft systems, then put the battery in steel box to contain any future events. Testing including inducing a full Li battery runaway/fire inside the steel box to insure it would be contained.
In the four plus years since the introduction of the Li battery system redesign there have been no Li battery fires. There was one reported battery "incident" where a single cell apparently shorted - the failure did not propagate. The in-service 787 fleet is now well over 400 aircraft with average utilization of over 10 hours/day.

Don't confuse any of these doubters with the facts. As for the 787 being noisy, I don't think so but I do agree that the 380 is a very quiet airplane and AirBus should be commended for this. I would rather ride the the 380 than the 787 for 10+ hours.

Spooky 2

Originally Posted by peekay4 View Post
Apparently this was a false alarm. There was a smell on board and fire service was dispatched as a precaution. But they didn't find anything and left after 30 minutes.

Well. Funny thing about "doubt". Doubt is an intuition, sometimes based on facts, to some extent or another. While one may take information in and make a conclusion, another may have some misgivings.

"They didn't find anything..." "It was a false alarm..."

The assumption was the fire service was summoned due to "smoke". There was none observed? Was the alarm related to "smell" only? What was the nature of the odor? What was the local reaction to the smell?

Some of us are satisfied with a rumor of "false alarm" others not? This aircraft has an unfortunate history of thermal runaway, causing damage. Fortunately, (for Boeing?) the 'fix' involves encasing the offending kit in a box, with a post CA exhaust that pretty much hides evidence of further trouble...

Anyone but Boeing know how many problems have occurred? Does it rise to the level of "incident"? Or does Boeing simply change out the charcoal remnants with a new battery, as they did, without reporting the failures, as before? Does it make it to the aircraft log? Certainly, right?