Lithium ion/Boeing 787

Discussion in 'Fred's House of Pancakes' started by tochatihu, Jan 18, 2013.

  1. tochatihu

    tochatihu Senior Member

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    Most Prius lack Li ion batteries, but most here have other experience with them. Now, after a couple of 'smokes', all 787 are on the ground and under study. Is this something that we ought to discuss? can the growing BEV market teach something that the NTSB and Boeing ought to learn?

    Anyway, the B787 is far beyond other planes in terms of running operating systems electrically. In this way, I reckon it resembles BEV cars except as needing airports for landings :)

    Any thoughts? Beyond 'Li ion get very hot with overcharge", because we already know that. For me it is not the batteries, instead the I/O control systems...
     
  2. Flaninacupboard

    Flaninacupboard Senior Member

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    I'd be interested if anyone has more info, what chemistry/cell was it? Was it the cells which burned? The pictures I saw on the news of the "battery" didn't look like a recognisable battery cell to me.
     
  3. cwerdna

    cwerdna Senior Member

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  4. spiderman

    spiderman wretched

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    Um, a little tweaking here and there and it will be good as new. :)

    Looks like the I/O is part of the encasement.
    [​IMG]
     
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  5. Flaninacupboard

    Flaninacupboard Senior Member

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    That's a good image. The fire really doesn't look that bad though.
     
  6. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    They are Lithium Cobalt, very different then what is used in the Plug-In Prius. Very very different. These chemistries are extremely exothermic when over-charged. So the first whammy is their charging circuitry is obviously crap not accounting for the change in battery properties over pressure changes. When you go high into the air, you can't assume you are charging like at sea level. The second whammy is the poor choice of chemistry means that when it does overcharge, it doesn't just fizzle and die, it pretty much explodes the outer casing and starts a fire.

    Remember a few years ago when laptop batteries were catching fire? Same thing. Same chemistry.
     
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  7. hyo silver

    hyo silver Awaaaaay

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    Just like a collision at sea can ruin your whole day, any fire in an aircraft is usually serious.
     
  8. tochatihu

    tochatihu Senior Member

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    Thanks toaster. I understood that the entire fuselage would be pressurized to 6000 feet throughout the flight. While this is not the same as sea level, it is hard (for us rookies) to accept that Boeing would not have heavily stress-tested full-scale simulations under such conditions. Actually I was thinking more along the lines of temperature, not pressure. Perhaps they were expecting the cold outside to contribute a lot to thermal unloading. For flights so far, usually it does but sometimes...

    Again just rookie talk. Looks like this design has so far, trained the largest proportion if its actual passengers in evacuation slide procedure :) That could be seen as a positive.

    But the 787 is tasked for long overwater routes where you don't always have a diversion airport handy. I don't know if ETOPS looks solely at engines, or the entire system.
     
  9. Chuck.

    Chuck. Former Honda Enzyte Driver

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    Here is an example

    [​IMG]
     
  10. paprius4030

    paprius4030 My first Prius

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    You won't catch me in one LOL. Let somebody else be the guneiua pig. (I know I can't spell)
     
  11. xs650

    xs650 Senior Member

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    I would also expect that before introducing a battery system technology into the aircraft they would have thoroughly studied the various failure modes and done adequate design and testing to assure they were reliable and safe. It makes me wonder if the Boeing suits subbed the battery system work out to some outside low bid "experts" that weren't as versed in reliability and safety as long time Boeing people.

    As far as counting on thermal unloading, any modern commercial or military aircraft need to be able to operate stuck on a runway in places like Saudi Arabia or Dubai for hours at a time without catching on fire.

    I hope Boeing manages to fix this in time to save their 787 business, Boeing has been a great company and is important the to the US economy. This whole thing sounds more like something Airbus would have done.
     
  12. Chuck.

    Chuck. Former Honda Enzyte Driver

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    Boeing outsourced various parts globally far more than any plane they built previously...accounting for many of the 787 delays.
     
  13. xs650

    xs650 Senior Member

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    I hope they learn their lesson from that. Outsourcing to buy expertise you don't have inhouse can be a good thing as long as you have enough competence inhouse to know what you are buying and the funding to use that expertise.

    Outsourcing just to save money also often includes a lack of oversight because the bean counter based decisions that caused the outsourcing in the first place often cut the funds needed for proper oversight.
     
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  14. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    Boeing continues to become more and more of a industrial conglomerate/political entity than aircraft manufacturer. In the space business, what happened to all the companies making rockets? Right now Space-X is doing the latest rocket builds. Boeing is on a downhill trend just like GM went downhill once they thought they owned the market. The "old" Boeing would have never let something like this happen.

    (P.S. The companies move to Chicago is another example. Locating the HQ far from all engineering and production can only be motivated by reasons "more important" than the products.)
     
  15. cwerdna

    cwerdna Senior Member

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    ^^^
    When Boeing did that, my guess was so that their executives could be insulated from labor disputes and protests that occurred rather frequently. I doubt most protesters would fly to Chicago to picket in front of their HQ.
     
  16. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    That certainly could have been a factor. On the humor side, the more I think about it, the more sense it makes.

    1. When a controversial decision needed to be made, they could wait till the nastiest, coldest winter days. Frozen protester are easier to get by than soggy protesters.

    2. The protesters that do fly would likely have to fly in a Boeing jet....a win-win situation for both sides.

    3. Chicago has taller buildings. More distance from the riff-raff.
     
  17. tochatihu

    tochatihu Senior Member

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    From BBC

    BBC News - US widens Dreamliner safety probe after battery finding

    "...
    Last week, the Federal Aviation Administration (FAA) said both batteries had leaked electrolyte fluid and there had been smoke damage to parts of the aircraft.
    The NTSB said a group of experts would meet in Arizona this week where the battery charger is manufactured by Securaplane Technologies to test and examine the part.
    The battery charger maker, a unit of Britain's Meggitt, said it would fully support the US investigation. United Technologies, which builds the aircraft's auxiliary power unit, said it would also cooperate...."

    Actually I am surprised how small the battery box really is. As this plane's flight-control systems are electrical, we can presume that the heavy electrical demands are met from the APU (on the ground) and however they take power off the 2 engines in flight. Elsewhere in the BBC article said the APU 32 (design) voltage had not been exceeded in the incident planes. So, unless they got a bad batch of YUASA cells (which would be very very bad), it looks like the ball is in Meggitt/Securaplane's court.
     
  18. fuzzy1

    fuzzy1 Senior Member

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    The word here is that each battery is 1.5 to 2 times the size of common automotive 12V batteries. The pictures betray no cooling system.

    Besides the two main engines and APU, commercial jets typically have a ram air turbine that can be popped out into the airstream if all engines fail. Older jets use it at least for hydraulic power, not sure about electric. I'd be surprised if the 787 doesn't also have it, for electric power.
     
  19. tochatihu

    tochatihu Senior Member

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    A little more 'reveal' on this

    NTSB: Boeing 787 battery shows short-circuiting

    We still have two suspects for the crime (so to speak). Securaplane has to confirm (reconfirm) that their hardware and software entirely fills the envelope of conceivable operating conditions. YUASA has to demonstrate that production line is amazingly close to 'zero defect'. I would suggest that the second task is the harder. It is relatively routine to make resistors, capacitors, inductors, semiconductors that perform precisely as specified. Perhaps not so much for the very young field of large-format Li battery winding.

    Again, turning to our battery experts: I want to torture test a Li battery assembly in the most severe ways, that would not actually cause degradation to a perfectly built assembly. What would I do?
     
  20. zenMachine

    zenMachine Just another Onionhead

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