ANA and JAL Ground 787 fleets 1

[dik]

...from the BBC, "Airline safety inspectors have found no faults with the battery used on Boeing's 787 Dreamliner, Japan's transport ministry has said.

The battery was initially considered the likely source of problems on 787s owned by two Japanese airlines.

The world's entire fleet of 50 787s has been grounded while inspections are carried out.

Attention has now shifted to the electrical system that monitors battery voltage, charging and temperature."

Maybe the charging circuits... or how the batteries are used...

Dik

 

[hokie66]

There would be lot of engineers, in a lot of different companies, doing a lot of overtime on this. Those of us who know little about it can only hope they will find the problem(s) without any remaining uncertainty.

 

[dik]

...from the Winnipeg Free Press, "TOKYO - A probe into the overheating of a lithium ion battery in an All Nippon Airways Boeing 787 found it was improperly wired, Japan's Transport Ministry said Wednesday.

The Transport Safety Board said in a report that the battery of the aircraft's auxiliary power unit was incorrectly connected to the main battery that overheated, although a protective valve would have prevented power from the APU from doing damage."

Dik

 

[Higgler]

from

http://www.wired.com/autopia/2013/02/airbus-ditches-lithium-ion/

hints dendrite growth, but doesn't sound conclusive if the whole thing burned an the word "appears" is used.

The news from Airbus comes roughly a month after the Federal Aviation Administration grounded Boeing’s new Dreamliners after two mishaps involving the planes’ lithium-ion batteries. Investigators continue to look into what caused a battery fire on-board a 787 parked in Boston, and a smoking, melted battery during a 787 flight in Japan.

The National Transportation Safety Board’s most recent update says it appears dendritic crystalline growth occurred in one of the eight battery cells inside the 63 pound lithium-ion batteries Boeing installed in the Dreamliners. The dendrites likely pierced the cellophane-like separator between the cathode and anode, leading to a short that caused the battery to catch fire. Dendrites are a common problem within the power packed lithium-ion batteries, Li-ion battery expert Dr. K.M. Abraham told Wired last week.

 

[IRstuff]

Well, of course they; that;s called "ghosting" your competition.

TTFN
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[MintJulep]

If we elect to believe the media then there appear to be two independent problems.

Dendrites growing inside the batteries.

Miswiring external to the batteries.

 

[KENAT]

Well, I don't know about you but when I've done failure investigations of our kit I've sometimes found more than one additional issue which may or may not be obviously linked to the actual 'failure'.

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[MintJulep]

Everything I've ever done has been perfect the first time, so I wouldn't know.

 

[KENAT]

I didn't say it was design faults, or even my design;-).

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[bigTomHanks]

Could the composite airframe have poor grounding circuits that result in additional loading on the ciruit, causing the batteries to overheat? This would be very difficult to correct, which would explain why Boeing would be interested in redesigning the battery for larger capacity rather than tearing the whole plane apart.

 

[hokie66]

Good to see the 787 back in the air.

http://edition.cnn.com/2013/05/07/t...ind-the-scenes/index.html?iid=article_sidebar