Problems with the Dreamliner battery

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In summary: Basically, it's a new design that allows the aircraft to operate with a smaller number of batteries and keep the batteries in a more stable and safer condition. As a result of this design, there have been some concerns raised about the possibility of an interaction between the battery and the electric power distribution system. However, so far no such interactions have been reported.
  • #1
Greg Bernhardt
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Surprised there hasn't been a thread for this big topic. Any experts out there want to weigh in on what the problem is, how it can be fixed and what this means for Boeing?

As Boeing and airline officials sought to assure travelers of the overall safety of the world's newest jetliner, federal safety officials Thursday painted a graphic picture of a disaster averted, displaying the charred remnants of a battery that "spewed molten electrolytes" from its container shortly after landing in Boston earlier this month.

http://www.cnn.com/2013/01/24/travel/dreamliner-investigation/index.html?hpt=hp_t1
 
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  • #2
The thermite-style failure mode reactions are well know so I'm sure the calculation was made showing the frequency of it happening being very low. At least the means to handle it until burning out seems to be working.

http://www.fire.tc.faa.gov/pdf/systems/lithium-ion_battery_04112006.pdf
http://www.wpi.edu/Pubs/E-project/Available/E-project-121306-105357/unrestricted/CPSCIQP2006.pdf
http://seattletimes.com/html/businesstechnology/2020199686_787batterysafetyxml.html?prmid=4939

To completely rule out any catastrophic high-energy fire or explosion that could result from overcharging a battery, Sinnett said, Boeing designed four independent systems to monitor and control the battery charge.

However, he conceded that if an internal cell shorts and overheats, “the electrolyte can catch on fire and that can self-sustain.”

“Something like that is very difficult to put out,” Sinnett said. “Because the electrolyte contains an oxidizer, fire suppressants just won’t work.”

Boeing’s design solution is to contain that outcome until the combusting battery cell or cells burn out.

“You have to assume it’s not going to go out,” Sinnett explained. “You have to assume that it’s going to go and that it’s going to expend all of its energy.
...
During testing of a prototype charging-system design in the 2006 incident, “the battery caught fire, exploded, and Securaplane’s entire administrative building burned to the ground,” according to a summary by the administrative law judge in a related employment lawsuit.
 
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  • #3
There have been many problems with the Dreamliner but this was expected. It represents, by all accounts that I've heard, the biggest change in the construction of commercial airliners since we started building them. Note that it doesn't even have an airframe by traditional standards. So none of this is surprising. And they have probably solved problems far more difficult than this along way a thousand times over before the craft was certified for flight.

Obviously everyone is anxious to get any remaining issues resolved but it seems to be a phenomenal aircraft. AFAIK, this and the previous delays are mainly PR and cash flow issues and not surprising from an engineering perspective.
 
  • #4
Ivan Seeking said:
It represents, by all accounts that I've heard, the biggest change in the construction of commercial airliners since we started building them.

Indeed, and the outcome is pretty much what you would expect from a project with so many unknowns - delivered years late, way over budget, and doesn't work.

Igmore all the BS public relations that "it's safe to fly". If anybody could come up with a creative argument that is it WAS safe to it was safe to fly, it would still be flying.

The FAA also has some backtracking to do, considering it agreed new regulations specifically to certify the new 787 electrical system. I'm not expecting any quick resolution for this.

Boeing have bet the farm on this one. The only good news here is, the 787 hasn't killed anybody ... yet.
 
  • #5
AlephZero said:
Indeed, and the outcome is pretty much what you would expect from a project with so many unknowns - delivered years late, way over budget, and doesn't work.

Igmore all the BS public relations that "it's safe to fly". If anybody could come up with a creative argument that is it WAS safe to it was safe to fly, it would still be flying.

The FAA also has some backtracking to do, considering it agreed new regulations specifically to certify the new 787 electrical system. I'm not expecting any quick resolution for this.

Boeing have bet the farm on this one. The only good news here is, the 787 hasn't killed anybody ... yet.

Why so negative? An Airbus fan I presume? :biggrin: There are issues but internally I don't hear any concerns like this.

Of all the concerns that one might have for something this innovative, a battery problem seems pretty hard to worry about. There have been far bigger bumps along the way.
 
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  • #6
Boeing 787 Electrical System

The 787 has been in the news much after recent battery fires. In media aricles I found several references to a possible interaction between the battery and the 787's unique electric power distribution system.

What's so unique about the 787's electric power distribution system?

Can anyone please provide a link to an article about it?

Thanks.
 
  • #7


anorlunda said:
The 787 has been in the news much after recent battery fires. In media aricles I found several references to a possible interaction between the battery and the 787's unique electric power distribution system.

What's so unique about the 787's electric power distribution system?

Can anyone please provide a link to an article about it?

Thanks.

This is the closest I've found so far, but it's not much help:

http://www.newairplane.com/787/design_highlights/#/visionary-design/systems/electric-architecture

Click on the "Read More" button in the upper right. It only seems to be saying that there are more electrically operated items and fewer pneumatic/hydraulic items...
 
  • #8
And this DesignNews interview with Boeing's lead engineer on the 787 seems to be saying the same things -- more electricity power devices (like air conditioning) and less pneumatics...

http://www.designnews.com/document.asp?doc_id=222448&dfpPParams=ind_184,aid_222448&dfpLayout=article

.
 
  • #10


anorlunda said:
The 787 has been in the news much after recent battery fires. In media aricles I found several references to a possible interaction between the battery and the 787's unique electric power distribution system.

What's so unique about the 787's electric power distribution system?

Can anyone please provide a link to an article about it?

Thanks.
I think it is the objective to reduce mass, which means increased power density. The Li-batteries have a smaller mass, but apparently flammable electrolytes.

As far as I know, aircraft use electricity from generators driven from the jet engines. When the engines are shutdown and before the external power supply is connected, the batteries provide power. Some aircraft have small turbine powered auxilliary power units (APUs) in the tail.
 
  • #11
Similar threads merged.
 
  • #12
Ivan Seeking said:
Why so negative? An Airbus fan I presume? :biggrin: There are issues but internally I don't hear any concerns like this.
I tell it the way I see it. Both companies have made some pretty good aircraft, and some less good ones.

IMO some of the other 787 problems in the news (e.g. brake failure, fuel leak, cracked window) ARE in the "no big deal" category. You don't ground an aircraft type permanently worldwide because of stuff like that. But the 787 electrical system is in a different league - it's a totally new concept and covers far more functionality than on any previous commercial aircraft. If that doesn't work, the problems are big time, and could involve huge amounts of redesign work - including knock-on effects like redesigned engines.

There were some "11th hour" electrical problems with the flight test programme back in 2010, which caused more delays to entry into service. Unsurprisingly, there's not much in the public domain about what really happened back then, but sometimes stuff like that comes back to haunt you...

One measure of the seriousness of grounding an entire aircraft type is how rarely it happens. The last time was back in 1979 (the DC-10, following a crash).
 
  • #14
spook - your link suggests a safer alternative battery?

http://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

at first glance one has to ask "why didn't they... ?"

I have a strong opinion - some parts of machines should remain mechanical instead of electric. I won't own an automobile with electric steering or a computer between my foot and throttle & brakes.
Or a huge li-ion battery right under my butt. Some years back a small one in my pocket nearly set my pants afire.

old jim
 
  • #15
jim hardy said:
spook - your link suggests a safer alternative battery?

http://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

at first glance one has to ask "why didn't they... ?"

I don't know why but lithium cobalt oxide batteries would not have been my choice for a large electrical system design where safety was a top priority. I've been designing an off-grid solar battery management system for a future retirement home and will never have them inside my house at the power levels I need for daily power storage (>5kWh daily). They just have really bad failure modes because IMO the lithium metal reaction is intrinsically unsafe as Boeing was using 4X redundancy in the BMS to prevent problems that are still happening.

Remember Dell?
http://www.telegraph.co.uk/news/1526424/Exploding-laptops-prompt-Dell-battery-recall.html
 
  • #16
Can they just work with the current battery and retrofit an emergency battery jettison system? :devil:
 
  • #19
The FAA Boeing 'special battery conditions' http://www.gpo.gov/fdsys/pkg/FR-2007-10-11/pdf/E7-19980.pdf

Boeing planned to change the batteries:
http://www.flightglobal.com/news/ar...-787-lithium-ion-battery-service-life-224663/

As Boeing activated the electrical system of its 787 for the first time last week, the airframer acknowledged that it was exploring a change to its power system for production aircraft due to longevity concerns.

Boeing will move away from its original lithium ion battery design for its main and auxiliary power units, flight-control electronics, emergency lighting system and recorder independent power supply. Instead, Boeing is investigating the incorporation of manganese inside the lithium ion battery to boost service life.
 
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  • #20
Thanks spook !
i never dreamed there are so many varieties of Li batteries..

From American Manganese:
http://www.canadianminingjournal.com/press-releases/story.aspx?id=1002006696
(bold mine - jh)
Green Car Report states lithium ion batteries are a family of products having very different performance characteristics resulting from incorporating specific alloying metals into the battery chemistry. Lithium plus manganese or/and nickel (or other metals) typically carry less energy per volume than lithium plus cobalt, but are widely viewed as less susceptible to overheating. The battery chemistry utilized by the Dreamliner was Lithium Cobalt Dioxide (LiCoO2); similar to that used in laptop computers and cell phones. American Manganese Inc.'s ("AMY") product would be Lithium Manganese Dioxide (LiMn2O4), or spinel, similar to rechargeable batteries used in the Chevy Volt. Both of these battery chemistries come under the generic heading "lithium Ion Batteries".

and from Battery University:
credit for the graph: http://batteryuniversity.com/learn/article/types_of_lithium_ion
li_9(1).jpg

Battery University's page is worth a look. It rates cobalt variety less safe.
 
  • #22
Any change of battery system won't be a quick fix, because of the amount of re-certification required. This guy is talking about NiH, but I think the same would apply to a different sort of Li.
http://news.cnet.com/8301-11386_3-5...ry-solution-may-keep-787-grounded-until-2014/

Given the current situation, convincing anybody that you were confident about an accelerated test program (i.e. proving the safe battery life is X years with less than X years of testing) might be a tough argument to win.

But if they can demonstrate ANY safe life, they could resume flying so long as they can make enough replacement batteries. There have been instances of commercial aircraft flying with major engine parts replaced every 50 hours. That's as nice for the airlines as having to take your car for an all-day service once a week, for the indefinite future, but it's better than not flying at all.
 
  • #23
nsaspook said:
I see no isolation of the internal electronics from the cells and the boards don't seem to be potted to seal them from possible out-gassing.

Aside from that: since "everybody" knows Li batterrs do present a fire risk in some circumstances, why did somebody put them in a place where the fumes from a fire would vent into the passenger cabin and/or flight deck ?

Given that even aircraft engines have fire extinguishers big enough to put them out (and more than one per engine, in case the first extinguisher doesn't operate), it shouldn't be impossible to put out a battery fire - so long as all the nasty stuff gets vented overboard, and not into the lungs of the self-loading cargo.
 
  • #24
AlephZero said:
Aside from that: since "everybody" knows Li batterrs do present a fire risk in some circumstances, why did somebody put them in a place where the fumes from a fire would vent into the passenger cabin and/or flight deck ?

If you read the "special battery conditions" link, the ALPA asks questions about that and other topics and the FAA implies that Boeing has certified that the chances of it happening (fumes from a battery fire) is "extremely remote".

http://www.gpo.gov/fdsys/pkg/FR-2007-10-11/pdf/E7-19980.pdf
 
  • #27
nsaspook said:
If you read the "special battery conditions" link, the ALPA asks questions about that and other topics and the FAA implies that Boeing has certified that the chances of it happening (fumes from a battery fire) is "extremely remote".

The words "Extremely remote" have a precise definition in this context, namely that the expected rate of occurrence is demonstrated to be less than 1 event per 1 billion flying hours. In simple terms, it means something that is so unlikely to happen that you don't care if it kills everbody on the plane, and most likely you can't make any meaningful design changes to mitigate it anyway (which is certainly not the case if we are talking about a battery fire).

To put "1 billion flying hours" in context, a total manufactured fleet of say 2000 aircraft, with a life of 50 years each, flying 5000 hours a year, would accumulate half a billion flying hours - so there would be a 50/50 chance you would have one "extrememely remote" event in the complete in-service history of the aircraft type.

To clarify your quote, Boeing don't "certify" this on their own. First, the FAA agrees a procedure for demonstrating compliance with the condition. That might be purely theoretical (based on calculation), and/or involve experimental testing. Boeing (or their subcontractors or partners) then carry out the demonstration. The FAA then checks that the demonstration was carried out to their satisfaction, and if so the FAA grants the certification.

The "checks" can mean FAA observers being present while the demonstration work is being done, if they so wish (and they do sometimes so wish!).

So, following that process, what we actually have is two separate events, each in an aircraft with less than 100 hours flying time. Yeah, right, so there's nothing to worry about over the demonstration process here - not!
 
  • #28
Greg Bernhardt said:
Dreamliner: No fault found with Boeing 787 battery
http://www.bbc.co.uk/news/business-21230940

I don't agree, the current battery system is intrinsically unsafe for use in aircraft. The amount of control feedbacks needed to maintain the narrow range of 'safe' operation , stop a positive feedback loop of higher and higher energy releases combined with the need for much better containment makes me think they should have never been approved by the FAA for commercial flights.

Lithium Iron Phosphate might be a possible alternative but it might take years to redesign in.
http://www.mpoweruk.com/lithium_failures.htm
 
  • #29
AlephZero said:
To clarify your quote, Boeing don't "certify" this on their own. First, the FAA agrees a procedure for demonstrating compliance with the condition. That might be purely theoretical (based on calculation), and/or involve experimental testing. Boeing (or their subcontractors or partners) then carry out the demonstration. The FAA then checks that the demonstration was carried out to their satisfaction, and if so the FAA grants the certification.

I agree and have been on both sides of a product needing certification (non-aircraft). For anything that pushes the envelope of current technology the 'OEM' usually writes the new test specs as most 'agency's' with few exceptions are far from the experts in the field. Usually the thicker the report the better. :smile:
 
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  • #30
nsaspook said:
... The amount of control feedbacks needed to maintain the narrow range of 'safe' operation , stop a positive feedback loop of higher and higher energy releases combined with the need for much better containment makes me think they should have never been approved by the FAA for commercial flights.
...
http://www.mpoweruk.com/lithium_failures.htm

when one looks at that narrow safe operating area window in your link, one wonders what is time lag between internal cell temperature and the sensor reporting it to computer. In process control we sometimes use derivative to extrapolate back through time delays to process...

I'm keeping an ear out for details of that test in 2006 where a prototype test battery burned down the building housing the test lab. That sounds like a huge flag that these batteries need "kid glove" treatment.

The more significant problem may become the emerging reports that Boeing was warned about the safety of the batteries and associated systems as early as 2006. Those reports center on the actions of whistleblower Michael Leon.

Aviation reporter and blogger Ben Sandilands writes in Plane Talking that while employed at Securaplane, which brought together mission critical battery assemblies for the 787, Leon wrote a report on the battery technology planned for the 787 saying it was a flight of safety risk and that substitute battery technology should be used. A month later, Securaplane's main buildings were burned to the ground when a battery test went wrong. Leon was injured in the blaze. Securaplane reportedly tried to force Leon out of the company when he refused to ship what he considered an unsafe battery assembly to Boeing for use in the 787. That assembly later malfunctioned when installed in a prototype airframe.
http://www.aero-news.net/index.cfm?do=main.textpost&id=66f459f8-4d6b-452b-961a-6b80dc4830a1
Disclaimer - i come from Nuke industy. Some whistleblowers are great folks and some are Don Quixotes. Time will tell about Mr Leon, i have no inside scoop.

old jim
 
  • #31
http://www.ntsb.gov/news/2013/130127.html

Here is a NTSB media brief from a few days ago. http://www.youtube.com/watch?v=wVMkt3sFwh0&feature=youtu.be

My comments in a earlier post about the lack of circuit board protection is related to this: http://www.newsdaily.com/stories/bre90o0gk-us-boeing-dreamliner-japan-circuitboard/

Typically on a system that monitors a possible hazardous process there is a containment space and isolated protected controller area for the monitor and control electronics so if there is a problem the actual controller can be examined and not be turned into a useless cinder of carbon.
 
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  • #32
http://seattletimes.com/html/businesstechnology/2020241385_787deadbatteriesxml.html

An interesting article from the Seattle Times aerospace reporter notes that 100 to 150 of the lithium-ion 787 batteries have been returned to the manufacturer, Yuasa. The troubles with them at first sight seem separate from the two failures which have grounded the fleet, but the electrical system which monitors and controls the batteries is being closely scrutinized by the NTSB and other agencies.

Respectfully submitted,
Steve
 
  • #34
From that FAA airworthiness directive linked by spook:
The service information describes procedures for replacing lithium-ion main aircraft batteries, ..., with Ni-Cad or lead acid batteries. The agency is issuing this AD following evaluation of all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

well, some engineering manager is taking his lumps."Cutting Edge Technology" can cut one's career short.old jim
 
  • #35
This is a complete WAG :redface: but maybe we are seeing the effects of strong EM fields on the metal foils that are in tight coils inside each cell when operated at high energy combined with high density levels. Looking at the length of the foils from the Dreamliner cells they would seem to have a fairly large inductance. Rapid current changes from loads or from being charged at high variable rates could be causing some sort of voltage or current non-uniformity inside the cells from the magnetic field effects.
 

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