Boeing 787 toast

RCinFLA

I am very interested in following the investigation on the LiIon battery problems with the Boeing 787. It is a little hard to get full accurate info but a picture is worth a thousand words.

Attached is a photo released in Japan on the battery pack of the flight that made the emergency landing and evaculation.

I read in a previous release that they are using lithium cobalt oxide (LCO) type batteries which are somewhat more difficult to control. Major automakers early on refused to entertain the possibility of using LCO in passenger vehicles due to safety concerns. Seems kWH/kg ruled the decision process. There is a recent news release that said overcharging has been ruled out since flight recorder verified the battery did not exceed battery design criteria of 32 volts. To a person with tech knowledge on LiIon batteries that seems to be a very irresponsible statement. I guess if your ass is covered from a sub-vendor component block point of view then the multi-cell pack not being subjected to net overvoltage would get Boeing off the hook.

I would be very uncomfortable with any multi-series connected LiIon battery pack used for an airline that did not monitor individual cell behavior. It appears from the picture that there is individual cell monitoring but likely consolidated within the battery pack and simplied at an overall battery pack reporting level. The controller board shown in the photo is appearently sourced from a French company. Maybe a plot by Airbus to gig Boeing.

I predict the outcome with be a switch to safer LiIon chemistry, like LiFePO4 batteries with 100 Wh/kg versus 160 Wh/kg for LCO. Present aircraft NiCd standard is about 50 Wh/kg and would be very difficult to retro-adapt for 787.

This story is going to be interesting to follow. I hope it does not give LiIon batteries a permanent black eye in the view of the public.

waynefromnscanada

Re: Boeing 787 toast

I too have been watching this one very closely. Last I read is investigators are widening their view to include possible over current on discharge which could trigger overheating, or discharging too deeply which was suggested could make the batteries unstable, with results similar to overcharging. Will be very interesting to learn what the real cause/causes is/are.

niel

Re: Boeing 787 toast

it might be that the airlines went out on a limb with these batteries without a full understanding of them. as such, those in the decision making process will only point fingers elsewhere and deny knowledge or involvement fearing repercussions. i would not hold my breath waiting for real answers from any airline.

Shadowcatcher

Re: Boeing 787 toast

Boeing made the conscious decision to out source many components and they are paying the price, not only with just batteries. In part my feeling is that it was an attempt to sidestep union workers.

Cariboocoot

Re: Boeing 787 toast

Here's a wild idea: maybe the batteries were just plain defective. That can happen with any type of battery. It is especially possible with a new design. It could just be that no one did anything wrong, that everything did work out on paper, but still some undetectable flaw occurred which was enough to cause the problem.

Now that the possibility has been discovered, perhaps they'll design in some additional safety measures to prevent a future occurrence. Thermal detection and shut down, for example. Individual cell monitoring as RC suggested.

There's a lot of things that work in theory which when applied to the real world tend not to with a resounding "Hmm; it shouldn't have done that" from engineers and physicists. For a while when I was young my job was looking at things that didn't work, figuring out why, and pointing the finger at the responsible party. Sometimes there wasn't any responsible party; it just didn't work due to unforeseen circumstances.

The bigger concern here is not that the public will never know (media tends to drop a story after the initial sensationalism wears off) but that the huge number of people investigating it will water down the problem until no one knows what went wrong or what should be done. That happens too.

icarus

Re: Boeing 787 toast

Boeing has had LOTS of trouble with the design/build of the 787, due in large part from outsourcing design build around the world, rather than having in house. Parts not mating, things not fitting, not working together. It seems that they are paying a price for thier choice if a strategy. Will they fix it? Probably, but I'm guessing it is going to be expensive, both in pure dollars, but also in reputation.

Tony

inetdog

Re: Boeing 787 toast

Cariboocoot wrote: »

Here's a wild idea: maybe the batteries were just plain defective. That can happen with any type of battery. It is especially possible with a new design. It could just be that no one did anything wrong, that everything did work out on paper, but still some undetectable flaw occurred which was enough to cause the problem.

The fact that the difference in serial numbers of the two failed batteries was only 30 certainly supports the possibility of a bad batch or other construction problem. (But if all of the batteries of that exact model are going into 787s, that may not mean much.)

As to shutting down the battery before bad things happen, if the fault really is internal to the battery (internal short circuits, for example as was the case for the Sony laptop batteries) there is nothing that can be done from the outside to stop the reaction, not even cooling the battery.

BB.

Re: Boeing 787 toast

And these batteries power the flight controls in an emergency (electronic/electric controls--Little to no hydraulics as I understand). So shutting down the battery packs is a non-option.

Supposedly, they can switch to NiCad (many decades of use in aircraft) or Lead Acid for now--At the cost of extra weight/fuel consumption for the airlines.

-Bill

inetdog

Re: Boeing 787 toast

BB. wrote: »

And these batteries power the flight controls in an emergency (electronic/electric controls--Little to no hydraulics as I understand). So shutting down the battery packs is a non-option.

Supposedly, they can switch to NiCad (many decades of use in aircraft) or Lead Acid for now--At the cost of extra weight/fuel consumption for the airlines.

-Bill

One of the batteries runs the electronics in an emergency, possibly providing voltage stabilization at the same time. It also lowers the landing gear, so there is a minimal power requirement there! (Lowering the landing gear one wheel at a time when power is limited????)
The other may back up the first, but its primary job is as the starting battery for the Auxiliary Power Unit (APU) in the tail of the plane, so low internal resistance is critical. That makes it harder to replace it with a different chemistry because of the competing needs for long cycle life and starting current.

BB.

Re: Boeing 787 toast

NiCads have been used for decades to start turbines in aircraft--And they can take crazy recharging currents too.

-Bill

inetdog

Re: Boeing 787 toast

BB. wrote: »

NiCads have been used for decades to start turbines in aircraft--And they can take crazy recharging currents too.

-Bill

But they take up a lot more space and weight for the same amount of power. And they are either sealed cells with charging current limits or are open cells with maintenance requirements. Not to say it can't be done, but depending on how much space is available it could get interesting!

icarus

Re: Boeing 787 toast

Why can't they strt the APU with shore power?

Tony

inetdog

Re: Boeing 787 toast

icarus wrote: »

Why can't they strt the APU with shore power?

Tony

I think that they are planning for making the APU available without having to be at the gate or waiting for a tug to show up to jump start the APU. Lots more comfortable for the passengers and allows them to shut down the main engines sooner.
They may even have planned to use the APU for control power in flight in case of engine failure.

mtdoc

Re: Boeing 787 toast

RCinFLA wrote: »

I predict the outcome with be a switch to safer LiIon chemistry, like LiFePO4 batteries with 100 Wh/kg versus 160 Wh/kg for LCO. Present aircraft NiCd standard is about 50 Wh/kg and would be very difficult to retro-adapt for 787.

This story is going to be interesting to follow. I hope it does not give LiIon batteries a permanent black eye in the view of the public.

Thanks for pointing this out. My thoughts exactly. Pity many don't understand that there is big differences between Lithium battery chemistries in terms of safety. All they take away is "Lithium batteries are dangerous" . Lithium Iron Phosphate is safe and not subject to fires like many of the other lighter lithium battery chemistries. It seems that aircraft companies, like most electric auto makers - are just too tempted by the the higher Wh/Kg ratio of the more unstable Lithium chemistries...

Lee Dodge

Re: Boeing 787 toast

inetdog wrote: »

I think that they are planning for making the APU available without having to be at the gate or waiting for a tug to show up to jump start the APU. Lots more comfortable for the passengers and allows them to shut down the main engines sooner.
They may even have planned to use the APU for control power in flight in case of engine failure.

Your comment reminded me of the new Boeing 767 in the Air Canada fleet that they ran out of fuel in-flight and lost both engines. Luckily, the designers had added a small air-powered turbine that extended out of the bottom of the aircraft and gave them minimal emergency electrical power to maintain control of the aircraft in case of complete engine failure. Story is at http://www.kls2.com/cgi-bin/arcfetch?db=sci.aeronautics.airliners&id=%3Cairliners.1994.1403@ohare.chicago.com%3E . The story makes you appreciate that there can be a learning curve with new aircraft.

ggunn

Re: Boeing 787 toast

Lee Dodge wrote: »

Your comment reminded me of the new Boeing 767 in the Air Canada fleet that they ran out of fuel in-flight and lost both engines. Luckily, the designers had added a small air-powered turbine that extended out of the bottom of the aircraft and gave them minimal emergency electrical power to maintain control of the aircraft in case of complete engine failure. Story is at http://www.kls2.com/cgi-bin/arcfetch?db=sci.aeronautics.airliners&id=%3Cairliners.1994.1403@ohare.chicago.com%3E . The story makes you appreciate that there can be a learning curve with new aircraft.

Was that the incident where they were out over the ocean and barely made it to an island with an airstrip?

inetdog

Re: Boeing 787 toast

ggunn wrote: »

Was that the incident where they were out over the ocean and barely made it to an island with an airstrip?

Nope. They were over land, just without a regular airport in range. And without functioning nose gear, as they found out when they tried to lower it at the last minute to avoid drag. :-)

westbranch

Re: Boeing 787 toast

Nope, it is the one that put GIMLI MANITOBA back on the map... in a hurry I might add. Where the hell is Gimli??? At least the pilot knew of it...

inetdog

Re: Boeing 787 toast

westbranch wrote: »

Nope, it is the one that put GIMLI MANITOBA back on the map... in a hurry I might add. Where the hell is Gimli??? At least the pilot knew of it...

The controllers knew of it too and suggested it. But the fact that the pilot had been based there once helped. (He still landed on the wrong runway, though.)

RCinFLA

Re: Boeing 787 toast

Lee Dodge wrote: »

Your comment reminded me of the new Boeing 767 in the Air Canada fleet that they ran out of fuel in-flight and lost both engines. Luckily, the designers had added a small air-powered turbine that extended out of the bottom of the aircraft and gave them minimal emergency electrical power to maintain control of the aircraft in case of complete engine failure. Story is at http://www.kls2.com/cgi-bin/arcfetch?db=sci.aeronautics.airliners&id=%3Cairliners.1994.1403@ohare.chicago.com%3E . The story makes you appreciate that there can be a learning curve with new aircraft.

Brings back old memories. My mother had a copy of Readers Digest on the table I picked up and read the article.

As the story goes it was the first jet the ground crew and flight crew experienced with everything in recent metric conversion. There was a long discussion at the gate between the pilot, copilot, and ground service crew over conversions between tanker truck gallons, liters, and pounds of fuel. To make a long story short they all decided on a number that resulted in about half the fuel needed to get where they wanted to go. I think it was somewhere near Calgary where they ran out of fuel and made the first 767 dead stick landing on an abandoned military airbase. Believe there was a TV movie made of the story sometime later.

Eric L

Re: Boeing 787 toast

Here's a discussion with more info on the 787's battery type, charger design, manufacturers, etc.:

http://www.pprune.org/tech-log/505695-787-batteries-chargers.html

waynefromnscanada

Re: Boeing 787 toast

RCinFLA wrote: »

Brings back old memories. My mother had a copy of Readers Digest on the table I picked up and read the article.

As the story goes it was the first jet the ground crew and flight crew experienced with everything in recent metric conversion. There was a long discussion at the gate between the pilot, copilot, and ground service crew over conversions between tanker truck gallons, liters, and pounds of fuel. To make a long story short they all decided on a number that resulted in about half the fuel needed to get where they wanted to go. I think it was somewhere near Calgary where they ran out of fuel and made the first 767 dead stick landing on an abandoned military airbase. Believe there was a TV movie made of the story sometime later.

I remember that one as if it were yesterday. A lot of very lucky people to have survived that close call!

Eric L wrote: »

Here's a discussion with more info on the 787's battery type, charger design, manufacturers, etc.:

http://www.pprune.org/tech-log/505695-787-batteries-chargers.html

Very interesting read. Thanks for posting this.

Slappy

Re: Boeing 787 toast

Nut shell update ...news cast said cells short circuited. Then chemical reaction. Claimed by new evidence

waynefromnscanada

Re: Boeing 787 toast

Slappy wrote: »

Nut shell update ...news cast said cells short circuited. Then chemical reaction. Claimed by new evidence

Awesome they're hopefully getting to the root of the problem!

waynefromnscanada

Re: Boeing 787 toast

Sat Jan 26, 2013 3:54am EST
* ANA cancels another 379 Dreamliner flights
* ANA says 82,620 passengers affected by grounding
* Regulators, experts suggest probe may take months. OUCH
http://www.reuters.com/article/2013/01/26/boeing-dreamliner-ana-cancellations-idUSL4N0AV05T20130126

nsaspook

Re: Boeing 787 toast

IMO the Lithium-cobalt reaction is intrinsically unsafe as Boeing was using 4X redundancy in the BMS to prevent problems that are still happening. The only safe solution is to use something else without thermite-style failure modes.

http://cdn.intechopen.com/pdfs/10407/InTech-Thermo_chemical_process_associated_with_lithium_cobalt_oxide_cathode_in_lithium_ion_batteries.pdf

waynefromnscanada

Re: Boeing 787 toast

nsaspook wrote: »

IMO the Lithium-cobalt reaction is intrinsically unsafe as Boeing was using 4X redundancy in the BMS to prevent problems that are still happening. The only safe solution is to use something else without thermite-style failure modes.

http://cdn.intechopen.com/pdfs/10407/InTech-Thermo_chemical_process_associated_with_lithium_cobalt_oxide_cathode_in_lithium_ion_batteries.pdf

Excellent eye opening read. Thanks for sharing.

inetdog

Re: Boeing 787 toast

nsaspook wrote: »

IMO the Lithium-cobalt reaction is intrinsically unsafe as Boeing was using 4X redundancy in the BMS to prevent problems that are still happening. The only safe solution is to use something else without thermite-style failure modes.

The circumstances and the findings so far are very very reminiscent of the Sony cell failures in laptop batteries. If I recall correctly, the root cause in those cases was a manufacturing process defect which left small sharp metal shavings inside the battery, and as a result of vibration, thermal cycling, etc. these metal particles eventually punctured the separator of a single cell and caused a local short circuit. The resulting heat drove that cell, and eventually adjacent cells into thermal runaway without any external power source contributing.
It is notable that an internal short circuit is the only defect that could bring about this type of event both without any early warning and with absolutely no way of halting the process externally short of either flood cooling the battery or jettisoning it. :-)
Even isolating each of the cells electrically would not have prevented the spread of the failure throughout the battery. If you design a containment system capable of surviving the thermal and electrolyte release from a single cell only, then you are making the same mistake that led to the derivative and mortgage crash in the US in a way not considered by the risk analysis applied by the regulators.

waynefromnscanada

Re: Boeing 787 toast

This morning's update:
"Aviation authorities find no big problems at Dreamliner's battery maker.
In a thermal runaway, a battery releases energy in the form of heat, increasing the temperature of the battery and causing further damage. In an electrical short, electricity follows an unintended path.
Neither event should have occurred on the Dreamliner, Deborah Hersman, chairwoman of the NTSB, said last week."
"There are multiple systems to protect against a battery event like this," she said. "Those systems did not work as intended, we need to understand why."
http://edition.cnn.com/2013/01/29/travel/boeing-dreamliner/index.html?hpt=hp_bn1
Boeing's chief rival, Airbus, had warned the airline industry of risks related to lithium batteries in March 2012, citing the risk of flames, explosion, smoke or leakage in the event of uncontrolled battery overheating.
Airbus, however, plans on using lithium-ion batteries on its upcoming A350 jetliner.

inetdog

Re: Boeing 787 toast

waynefromnscanada wrote: »

Neither event should have occurred on the Dreamliner

And either one could also cause the other. <sigh>
The containment system could probably have handled a single-cell failure, but when all 8 of them went....

solar_dave

Re: Boeing 787 toast

Elon offered to help Boeing

http://www.forbes.com/sites/davidewalt/2013/01/29/why-elon-musk-wants-to-help-boeing-fix-the-dreamliner/?partner=yahootix

Pretty Brilliant PR move IMHO.