Boeing 787 & Li-Ion batteries vs recent fires

This is not good for several reasons:

http://online.wsj.com/article/SB10001424127887323482504578227621155767836.html?KEYWORDS=Boeing

while at an exercise club at about 0640 this morning on Ch-355 on DirectTV, there was a long exchange about Li-Ion batteries replacing the usual electrical generation from bleed-air on Boeing 787s. Not only has the 787 had various fires, but systems have shut down in flight with no warning. All TBD.

[h=1]U.S., others ground Boeing Dreamliner indefinitely[/h]http://www.reuters.com/article/2013/01/17/us-boeing-dreamliner-idUSBRE90F1N820130117




[h=1]Batteries blamed in Boeing 787 grounding are widely used[/h]http://www.reuters.com/article/2013/01/17/us-boeing-dreamliner-faa-battery-idUSBRE90G06320130117

from http://www.nytimes.com/2013/01/18/b...e-ground-boeing-787s.html?pagewanted=all&_r=0
this artical, It has a Picture of this Power unit
http://www.nytimes.com/imagepages/2013/01/17/business/DREAM2.html
Different view found on google images (google images search dreamliner battery or dreamliner auxiliary power)
http://images.smh.com.au/2013/01/16/3956405/Art-Dreamliner-Battery-20130116122831682810-620x349.jpg

the A380 which has been flying for a few years now also has a lot of lithium ion batteries...

http://www.huffingtonpost.com/2013/01/16/787-grounded-faa-orders-a_n_2490941.html

"Mike Sinnett, chief engineer on the 787, said last week that the plane's batteries have operated through a combined 1.3 million hours and never had an internal fault. He said they were built with multiple protections to ensure that failures "don't put the airplane at risk".
The lithium-ion design was chosen because it's the only type of battery that can take a large charge in a short amount of time."

No wonder those batteries are having problems!

Why?

I'll bet on charging without removing them from the circuit, so a parasitic load causes them to charge at too high a voltage..

moldyoldy said:

http://www.huffingtonpost.com/2013/01/16/787-grounded-faa-orders-a_n_2490941.html

"Mike Sinnett, chief engineer on the 787, said last week that the plane's batteries have operated through a combined 1.3 million hours and never had an internal fault. He said they were built with multiple protections to ensure that failures "don't put the airplane at risk".
The lithium-ion design was chosen because it's the only type of battery that can take a large charge in a short amount of time."

No wonder those batteries are having problems!

Click to expand...

This is really UNTRUE. It is certainly not the only type of battery that can take a large charge in a short amount of time. The real reason to use Li-Ion batteries is that for the same capacity, the Li-Ion battery set is about 40 pounds lighter than the NiCd's usually used for this application.

In the Airline business weight savings=money savings. How much is 40 pounds worth each year? About $3000 at current Jet-A prices.

And as we all know, NiCd's can take immense abuse, and very rapid charging at the expense of battery life.

Older passenger aircrafts uses NiCd chemistry to store power from either the APU for the turbine from engine bleed,, is it possible [or even remotely plausible] that the 787's li-ion batteries are being maintained by an NiCd algorithm?

My personal theory is that there are two ways to use an airplane.. the first is the way the designers think people/airlines will use it, and the second is the way that people/airlines will actually use it!

My guess is that the batteries are getting used much harder than Boeing design and test engineers anticipated.

The example of this principle that sticks with me is the F-18 Hornet. It was designed with the ability to fly at high angle of attack, which was a big change from current aircraft. The pilots liked it so much that they spent much more time at high angles of attack. The downside of this is that the big vortices generated off the leading edge extensions beat the heck out of the rudders, causing cracks at the rudder bases. The fix was to add some ugly brackets at the rudder base, and some uglier strakes on the leading edge extensions. These can be seen on the F-18C/D models, but are eliminated on the F-18E/F models.
for reference, here's a shot of that strake on the leading edge:
http://www.flickr.com/photos/kurtsj00/5003952301/in/set-72157624827485299
The adjacent photos will help put it in context.

Anyway... I'm hoping that Boeing gets this under control soon. Maybe a switch to a less volatile lithium formulation? Tweak the software to be a bit more gentle with the charging and discharging?? Cross your fingers!

The verdict is not in, but the suspicions are very strong: excessive charge rate in to these Li-Ion batteries.

http://kstp.com/news/stories/S2901852.shtml?cat=1

"In the case of the 787 in Boston, the battery in the plane's auxiliary power unit had recently received a large demand on its power and was in the process of charging when the fire ignited, a source familiar with the investigation of the 787 fire in Boston told The Associated Press."

Evidently the Cessna Citation also had similar problems with Li-Ion batteries.

LiCo on Boeing 787

Here is a photo of the fried LiCo:
http://www.technologyreview.com/new...eamliners-use-batteries-prone-to-overheating/

Here is photo before "spontaneous combustion":
http://www.foxnews.com/science/2013...-responsible-for-boeing-dreamliner-grounding/

Comments? I realize the technical details are buried in a Boeing spec book somewhere. I also read that Yuasa made Boeing's lithiums. More info?

"An investigator in Japan, where a 787 made an emergency landing earlier this week, said the charred insides of the plane's lithium ion battery show the battery received voltage in excess of its design limits.
** *
The similarity of the burned battery from the All Nippon Airways flight to the burned battery in a Japan Airlines 787 that caught fire Jan. 7 while the jet was parked at Boston's Logan International Airport suggests a common cause, Japan transport ministry investigator Hideyo Kosugi said.
** *
"If we compare data from the latest case here and that in the U.S., we can pretty much figure out what happened," Kosugi said."

That about covers it, I'd say... :shrug:

TedTheLed said:

the charred insides of the plane's lithium ion battery show the battery received voltage in excess of its design limits.

Click to expand...

Since the charging system checks out, it almost sounds like the battery packs were wired up at a lower voltage. But it can't be that simple...

Single cell short out due to foreign object damage, which the pack survives without catching fire, but effectively drops the pack voltage by 3.7/4.2V?

heard on the news this morning that overcharging had been ruled out!

Will these cells have been charged using a ballanced charger so charge level imbalance would not happen.

John.

According to this Reuter's story, Dreamliner probe widens after excess battery voltage ruled out

Now, would it be wrong to say that among a large number of LiCo's after a decent amount of usage, even if a 'good' batch properly manufactured and properly designed recharging circuits, that a small % will fail anyway?

Battery Fire NTSB Briefing - JAL 787

For all you pilots, avionics techs, battery fiends, and just plain interested.

http://www.youtube.com/watch?v=83BT8NL_9EU

Re: Battery Fire NTSB Briefing - JAL 787

Thank you for that link! NTSB Chairman Deborah Hersman was very calm, collected and very much in control of the presentation. That was a masterful presentation, both from the aspect of a well-grounded presentation as well as from the political aspect of how to present a high-level in-process engineering root cause analysis to a technical public with Q&A allowed! Ms. Hersman very neatly avoided many of the pitfalls that so many corporate chairmen have fallen in to during Q&A (hence Q&A is usually not allowed). There is a lot of political and technical pressure on her and the NTSB in this very visible investigation of the Boeing 787 battery system. As importantly, Ms Hersman very clearly separated the responsibilities of the FAA from the NTSB.

Some observations about the information given: The cells were flattened, almost like a pocket plate NiCd cell, yet were a jelly roll construction. How much flattening occured after the jelly roll was wrapped? The information provided in this presentation omitted a report from a Boeing designer that the JAL Boston 787 battery underwent heavy current surges in/out of the battery just prior to the fire. However such information was dealt with by the repeated comment that the NTSB is attempting to understand what was being measured, how and where (& when). The photos provided by Ms. Hersman did show that the system intended to monitor the batteries seems to have suffered the most damage, although it was not clear where that circuitry was located in relationship to the cells.

Re: Battery Fire NTSB Briefing - JAL 787

I'm pretty sure what will end up happening is that Boeing will deflect to the manufacturer of the pack. If Boeing was only a commercial company I would say they were in serious trouble. A fleet grounding is as severe as it gets (hopefully).

Re: Battery Fire NTSB Briefing - JAL 787

I hope this long paste is ok.
if not here is the link:

1/27/2013 @ 10:25AM
MIT Professor: Battery Fix Could Ground 787 Until 2014

http://www.forbes.com/sites/peterco...ssor-battery-fix-could-ground-787-until-2014/

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