Boeing 787 Li-Ion Meltdown

[chicken]

I thought my fellow friends of electronic pron might appreciate this look inside the failed battery that grounded the Boeing 787 fleet:



Source: http://seattletimes.com/html/businesstechnology/2020162310_787japanbatteryxml.html

[SeanB]

Looks and probably smells similar to what the power supplies I worked on did when they died. CBB - Charred Beyond Belief.

[r90s]

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.

[G7PSK]

No doubt there will be a few cars do that as well especially after a collision, but that makes me wonder about the thinking of airlines and the various authorities governing air transport around the world, ban lithium batteries from airfreight and then allow whopping great big ones to be installed in the aircraft.

[rollatorwieltje]

Considering how violent a lithium battery fire is, that box held up pretty well. I want one of those to store my R/C LiPo cells.
I wonder what really caused it to catch fire. I just can't imagine Boeing didn't know rule 1 of dealing with lithium cells; "thou shalt not overvolt".

[(In)Sanity]

Ekkk,  what a mess.

I keep all of my LiPo packs in a fire safe.   I have far too many LiOn batteries around and packs.  Making me nervous..again.

Jeff

[fenclu]

I remember polish airlines bragging about their Dreamliners being the first in Europe. WELL, maybe the was a reason for that

[EEVblog]

Toasty!   

So, how long will it take them to get the planes back in the air I wonder?
I can't see it being less than many months... unless they deem this to be a rare one-off?

Dave.

[ttp]

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.

[JoannaK]

Toasty!   

So, how long will it take them to get the planes back in the air I wonder?
I can't see it being less than many months... unless they deem this to be a rare one-off?

Dave.

Dramatic battery failure has allready happened twice. Both in this month (at Boston airport and Japan in-flight), and there have been only 50(or so) dreamliners delivered. These planes are only about 1 year old, so it can't be due old age either.

For those who are interested.. http://www.gsyuasa-lp.com/aviation-lithium-batteries 

[Bored@Work]

3 why they don't pull the power from dynamos on the turbines.

They can't. They need these batteries to start the engines. And the batteries are the backup for power, should the engines fail in flight. It is my understanding they are the only source of power in such a case. So they are freaking important, and it is not only the fire as such what makes people nervous, but that they are badly needed in emergencies.

[NiHaoMike]

Why don't they use the safer LiFePO4 batteries?

[tom66]

Is the use of LiPo here to reduce weight, over conventional lead acid batteries?

[IanB]

Why don't they use the safer LiFePO4 batteries?

The energy density is vastly less, and LiFePO4 batteries are not really any safer in the event of an electrical fault. I once momentarily stroked a wire across the terminal of a big LiFePO4 battery in an absent minded way to see what kind of a spark I would get--OMG, don't do that!    The battery had such a low internal resistance that a momentary short produced instant smoke. Safety is relative, and a high power, high capacity battery of any type is not going to be pretty under fault conditions.

[IanB]

Is the use of LiPo here to reduce weight, over conventional lead acid batteries?

Have you considered the hydrogen/oxygen explosion risk of a lead acid battery on an airplane in flight?

[tom66]

Is the use of LiPo here to reduce weight, over conventional lead acid batteries?

Have you considered the hydrogen/oxygen explosion risk of a lead acid battery on an airplane in flight?

They've been used for quite a while and I thought that Li-Ion was mostly used because they weigh less.

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.

[HLA-27b]

Most planes still have NiMH I believe. The drive towards lighter smaller batteries made them go for Lithium. Also there are no hydrolics in the classic sense on the boeing plane (don't quote me on that) making it lighter yet and more <harrumph> reliable.


First Airbus with their exploding RR engines and wing cracks and now this one with melting batteries and fuel leaks. It seems beta testing with passengers on board is the new thing. Probably someone calculated that it would be cheaper to just pay insurance and crash a few instead of doing two years of pre-production tests.

[ejeffrey]

They can't. They need these batteries to start the engines. And the batteries are the backup for power, should the engines fail in flight. It is my understanding they are the only source of power in such a case. So they are freaking important, and it is not only the fire as such what makes people nervous, but that they are badly needed in emergencies.

They do have a ram-air turbine for emergency power in case of engine failure, so they do have backup power for the flight controls during an emergency landing.  Still, the battery is pretty important.

[SeanB]

Most aircraft do not have NimH but NiCad packs, as they are a lot more reliable, handle abuse with little problems and are reliable and have well known failure modes. Only problem is to fit the same capacity would take 3 standard cell packs and be 6 times the mass. Flooded cells that only need a vent and some cooling, and a temperature sensor to tell the charge controller to let back on the charge or to adapt to the voltage of the warming pack. Most of them run at ambient pressure externally and can contain the result of internal failure, though a thicker case would not go amiss. As a plus the standard size unit can be serviced by existing support systems with no extra tooling or new equipment.

The probable cause for these lithium failures I would guess is metal particle contamination introduced during manufacture from abraded metal particles from the production plant. Time frame is right for them to cause the failure.

[Skimask]

Solar panels on the top of the fuselage!

[SeanB]

Solar panels don't work well in thunderstorms where you are most likely to have an engine out due to either rain or hail. Not exactly good at night either.

[RCMR]

Lithium Ion/polymer batteries wouldn't be my first choice for an application where failure was likely to produce death.

While they have a fabulous energy:mass/volume ratio -- they're also very poor performers in low temperatures (ie: anything below about 5 deg C) so I can't see that they're such a good choice for a craft that spends much of its working life in sub-zero temperatures.

As someone else suggested, LiFePO4 chemistry would be a *much* better option and, although the energy:mass/volume ratio is lower, it's still more than good enough for aviation use and far ahead of the NiCd batteries they're presently using (which, by the way, work very well right down to sub-zero temps).

You really have to wonder, given that they're prepared to use Li batteries to save just a few Kg here and there, how many other components have been whittled away to the bare minimum in the quest for the lowest weight and thus the highest performance.

[Skimask]

Solar panels don't work well in thunderstorms where you are most likely to have an engine out due to either rain or hail. Not exactly good at night either.

Then I guess they'll have to switch to daytime / fair weather flying only!  Strictly VFR...
And every passenger gets one of those those "shake" flashlights with power cords.  Power goes out, everybody start shaking.

[amyk]

It's been pointed out somewhere else that one of the wires on the right side appears to have been pinched between the case and the cover and perhaps caused a short through abrasion of the insulation.

[PA0PBZ]

It's been pointed out somewhere else that one of the wires on the right side appears to have been pinched between the case and the cover and perhaps caused a short through abrasion of the insulation.

On that picture it certainly looks like one or 2 wires where pinched under the cover, but when you look at the other failed one in Boston there are no wires under the cover: