Dreamliner investigators suspect excess voltage in battery

CraigHicksJan. 20, 2013 - 02:15PM JST

It should be really easy and fast to equip these batteries with reliable voltmeters and thermometers, and an ON/OFF switch.

They already are. Perhaps not as reliable as they were expecting though.

I would like to know: If the battery is offline, can the electrics be run off engine turbo generator?

They normally are. There is no safety issue if the battery stops working (though it would be deemed an emergency worth landing for), only issues are with fire and control circuit shorts, though neither is usually fatal since there are redundancies and fire prevention methods.

It should be really easy and fast to equip these batteries with reliable voltmeters and thermometers, and an ON/OFF switch. I would like to know: If the battery is offline, can the electrics be run off engine turbo generator? Less badmouthing, more solutions please.

EppeeJan. 20, 2013 - 11:46AM JST

It does not mean anything, we don't have access to any numbers, no specific specs for those batteries

I already linked the cell specifications twice, I won't do it a third time. Check above for the link.

protection circuitry (if that was Yuasa's one)

http://www.gsyuasa-lp.com/aviation-lithium-batteries

Yuasa says they have battery management circuits built into each cell, and their other battery packs all feature over-charging protection.

If you are looking for more information scavenged by knowledgeable people, check this link (and the next few pages):

http://www.pprune.org/rumours-news/505348-ana-787-makes-emergency-landing-due-battery-fire-warning-9.html

And especially http://seattletimes.com/ABPub/2013/01/18/2020162338.jpg . You can see the battery management circuitry in the right hand battery near the top of the photo. Interestingly, they also broke down when the planes involved were manufactured, and it's two years apart, strongly implicating a bad batch of batteries from Yuasa sent directly to the airline maintenance crews.

It does not mean anything, we don't have access to any numbers, no specific specs for those batteries, protection circuitry (if that was Yuasa's one), requirement and data from the plane's electronic, etc. All the argumentation is only speculation, IMHO we should just wait the investigation results and make our opinion from then.

EppeeJan. 20, 2013 - 08:26AM JST

How do you know that, do you have access to Being specs ?!

Please read before you attack for no reason: "The individual battery cells for the aux batteries involved are said to be their new LVP line (http://www.s399157097.onlinehome.us/SpecSheets/LVP10-65.pdf), and the entire battery is a custom one designed for the 787"

Yuasa states their individual cells, and therefore entire battery too, are designed to be protected against over-charging and over-discharging. Doesn't matter if Boeing's specs are lower, Yuasa's specs state it.

basroil: "The problem IS with the battery (they are supposed to be designed to not leak even in overvoltage conditions. The secondary problem may be in the charger provided by Yuasa's contractor, Thales SA, which is supposed to regulate charging voltage." How do you know that, do you have access to Being specs ?! What overvoltage is guaranteed ? What overvoltage has been applied during the incidents ?

Thunderbird2Jan. 19, 2013 - 08:41PM JST

No has been hurt... so far.

You can say that about every new airplane. Most injuries and deaths occur once the number of frames is high enough that flight statistics start showing the weaknesses (and pilots make enough errors). So far the 777 has no deaths (but plenty of injuries), despite having some major issues far worse than the 787.

All it needs is another cracked windscreen over the Pacific,

No, cracked windows are fine, window blowouts are not, but they happen mostly with bird strikes and are rarely fatal. Here's a statistic that will keep you out of airplanes: http://www.foxnews.com/story/0,2933,582817,00.html

leaking fuel being ignited at take-off,

You've been watching too many movies. Die Hard 2 plane explosions don't happen. Fuel fumes inside landing airplanes is a far worse issue than take off. It's also limited to a single plane, so hardly an indicator of structural problems.

brakes failing on a landing...

Never happened on the 787, just a malfunctioning indicator that said it did. Even so, hardly something limited to this plane: http://newsfeed.time.com/2012/03/13/delta-jet-rolls-off-runway-at-atlanta-airport-after-brake-failure/

it isn't just the batteries.

The only thing that NTSB/FAA is investigating is the battery/power system issue. The others have been very limited in scope and not very high on their priorities since they are not normally life threatening.

@ Walter:

Fact - no one injured! It's safe and the saftey features do work. Every product has problems just like humans do. Get over it. If it weren't for upgrades and up dates you wouldn't be using a bicycle today. I have complete faith in both of the new aircraft being introduced.

No has been hurt... so far. All it needs is another cracked windscreen over the Pacific, leaking fuel being ignited at take-off, brakes failing on a landing... it isn't just the batteries.

In addition you can't blame the defects on the thing being built by international sub-contractors... Airbus, Panavia Tornado, Eurofighter Typhoon are all built using this method. It's a tried and trusted system.

Fact - no one injured! It's safe and the saftey features do work. Every product has problems just like humans do. Get over it. If it weren't for upgrades and up dates you wouldn't be using a bicycle today. I have complete faith in both of the new aircraft being introduced.

Harry_GattoJan. 19, 2013 - 05:37PM JST

The battery will have been designed to meet a specification which would have included tolerance of over-charging (current) and being supplied with excess voltage. This specification would however include "up to" limits of some kind for over voltage, over current and internal pressure caused by over-charging.

Yes, they would have some sort of charging limit and amount of normal and maximum charge voltage and current. Internal pressure isn't generally used, rather internal temperature as that is what can lead to fires. Generally 90C is the cutoff for battery temperature.

Larger batteries are generally designed with internal circuitry that manages individual cell performance and charging, in addition to the overall charging system. They generally also have cutoff systems to prevent charging once the thermal cutoff has been reached, yet that doesn't seem to have been triggered in either case.

I suspect that these tolerances were fairly tight bearing in mind that weight saving was a major factor in the aircraft's design

Weight saving doesn't have anything to do with tolerances in batteries though, thermal runaway and charging characteristics only depend on the technology used, not the size. Even rc plane batteries have built in cell balancing and shutoff circuits built in, as do Yuasa's other batteries.

The individual battery cells for the aux batteries involved are said to be their new LVP line (http://www.s399157097.onlinehome.us/SpecSheets/LVP10-65.pdf), and the entire battery is a custom one designed for the 787. According to them "The battery can charge from 0 to 90% in only 75 minutes and comes with battery management electronics which guarantees multiple levels of safety features. " Looks like those multiple levels of safety features aren't working as expected. That is where they are at fault for the batteries catching fire, even if Thales equipment was the ultimate cause. Only case where it wouldn't be their fault is in poor maintenance.

The problem IS with the battery (they are supposed to be designed to not leak even in overvoltage conditions. The secondary problem may be in the charger provided by Yuasa's contractor, Thales SA, which is supposed to regulate charging voltages.

The headline of this article is misleading and so is your statement. The battery will have been designed to meet a specification which would have included tolerance of over-charging (current) and being supplied with excess voltage. This specification would however include "up to" limits of some kind for over voltage, over current and internal pressure caused by over-charging. If these design parameters are exceeded then something has to give and the casing will eventually leak. I suspect that these tolerances were fairly tight bearing in mind that weight saving was a major factor in the aircraft's design. Time will tell of course and the results of the investigation should pin down the reason for the problem. Like you, my money is on over-charging due to faulty or poorly designed charge control equipment.

The Dreamliner is late in coming and I suspect more problems to follow.

Saw in the news yesterday that they think the problem is with a faulty regulator switch which should prevent overcharging.

bokatrJan. 19, 2013 - 02:35PM JST

Of course, you know better than the people who actually checked it.

Your statements are simply unacceptable, a direct attack for no reason, and absolutely incorrect based on the full statement you refused to quote. Not the brightest way to make your first post in a year an a half.

The problem IS with the battery

Of course, you know better than the people who actually checked it.

This is scary considering besides battery there was a fuel leak, cracked cockpit window, brake issues BEFORE this. I don't ever want to fly this plane!!!!

It said the problem could be the battery, the power source or the electronics system.

The problem IS with the battery (they are supposed to be designed to not leak even in overvoltage conditions. The secondary problem may be in the charger provided by Yuasa's contractor, Thales SA, which is supposed to regulate charging voltages.

sf2kJan. 19, 2013 - 09:22AM JST

why use such a well known faulty battery type?

That statement makes no sense on two counts. This specific battery pack has only been used in the 787, and thus can't be known to be anything other than what FAA testing showed, which was within the limits they prescribed. Also, Lithium-ion is not faulty as a technology, or else we would have hundreds of thousands of phones, laptops, and toys blowing up all the time. Although there are cases of fires due to lithium-ion batteries (passenger and cargo), there are plenty of similar events with lead-acid and ni-cd/ni-mh batteries that actually caught on fire in airplanes (mainship batteries, far more dangerous than passenger or cargo). On of those is Aloha Airlines Flight 845, which had thermal runaway in a Ni-Cd battery similar to those used in most commercial airliners. I'm sure you can find plenty more of those battery fires.

With no less than seven sub-contractors/designers, there is bound to be a problem. It's possible that whoever was responsible for the battery re-charge system didn't check with the battery maker.

There are many clear evidences there, we will know soon what causes made such failure. Let us wait and see...

kwatt :

Boeing 787 have been flying for 15 months and there was no problem

That is a good point. So, are you implying that 'someone' messed with the 787's purhased by Japan ?????? . . . . ................................. .HOWEVER to be completely honest, there were many other problems with the 787 with OTHER airplines, such as : BRAKE FAILURE/ ELECTRICAL GLITCHES DUE TO electrical distribution problems/ WINDSHIELDS CRACKING . . .and others

Boeing 787 have been flying for 15 months and there was no problem. Lithium ion batteries were checked very strictly and carefully before applied to Dreamliner. If excess electricity to the battery happened all the time, it would make fire even if there is fire safety device.

exceeded the batttery voltage operating limit as designed by japanese manufacturers...and it is a fire hazard material too

dream liner dream on

why use such a well known faulty battery type?

Elbuda Mexicano : it is not necessarily due to defective batteries. . ................................. It could be the way the whole electrical system was wired. . ................................. REMEMBER ; the Boeing 787 was designed and assembled in Seattle . . . .............................and the parts were made to Boeing's 'specs . . ........................There could have been a misculculation on the part of Boing's internal engineering team as to the optimun energy a 787 would require at a given time.

This so called "Dream Liner" sounds more like a nightmare!! I got a feeling the battery makers etc..are trying to cover up something and that this is only the tip of the iceberg!!!

You could be right. I mean our day wouldn't be complete without at least one conspiracy theory.

Not much you can hide when you got something burning right under the cockpit! Filling up the cockpit with smoke!! Have fun trying to put a positive spin on this!!

This so called "Dream Liner" sounds more like a nightmare!! I got a feeling the battery makers etc..are trying to cover up something and that this is only the tip of the iceberg!!!