Found in the news, Boeing's dremliner LiIon battery unit burned out picture

P E Schoen schrieb:

Hello,

when a single cell does not overheat, a compact block of several cells may overheat at the same current and duration.

Bye

Jan Panteltje schrieb:

Li-ion

13),

Hello,

a fuel cell like those used in the Apolle Service Module is not suitable for airplanes, you will need enough oxygen and hydrogen in pressured tanks or even as liquified gas.

Bye

Jan Panteltje schrieb:

13),

Hello,

it was not the fuel cells that exploded, it was the tank for liquid oxygen.

Bye

There are other forms of fuel cell which take butane or propane and air. Things have moved on a little.

--
Mike Perkins 
Video Solutions Ltd 
www.videosolutions.ltd.uk

Electric vehicle batteries are still below the power levels available in WWII submarine batteries. The first google hit claims 210 to 350 V at up to 15,000 amps (probably on the order of 1C). Some subs used a series connection of the two batteries to double this voltage and halve the current. Breakers and contactors designed to open under fault conditions used the standard air cooled design with a long arc chute lined with a stack of individually insulated metal plates, using magnetic field from a blow-out coil and/or permanent magnets to pull the arc into the stack of plates for cooling. Distance between open contacts was on the order of 3 cm IIRC. I am pretty sure that a contactor or breaker of this type specifically designed for an EV could be made with reasonable size and cost.

OT: I once worked with a former shipyard submarine battery electrician who was monitoring the recharge portion of a capacity test on an older sub with an open knife switch DC switchboard, with strict no smoking rules in effect due to hydrogen emission, when the ships electrician walks up to the switchboard, yanks open a knife switch a bit, lights his cigarette in the arc, and closes the switch again. The yard electrician said he nearly had a heart attack, which was no doubt the intention of the ship electrician :-).

On a sunny day (Fri, 25 Jan 2013 16:33:40 +0100) it happened Uwe Hercksen wrote in :

13),

This story I remember: After the Apollo 13 incident, a technician asked to speak to Dr Braun. He was given audience, and told Von Braun that while installing the fuel cells he accidently touched metal with a cable and a big spark happened. It seemed the fuel cell was internally damaged, without that technician knowing, and the technician never reported the incident. Von Braun did not fire the guy, but gave him a bottle of wine or something

- because now he did not have to redesign the whole electrical system -.

If the oxygen tank exploded it was likely a consequence of some fire staring in the defective fuel cell electrical system.

On a sunny day (Fri, 25 Jan 2013 16:31:53 +0100) it happened Uwe Hercksen wrote in :

Li-ion

13),

Of course, I never claimed that is was the *same* type.

Open knife-switch DC switchboard on a submarine? Carrying charging current for the ship's battery? Hmm... Makes a good story, though.

13),

knowing,

the

Wrong. The explosion was indeed in the tank and had nothing to do with the fuel cell itself. The insulation on the wiring to a stirring fan (used to "mix" the LOX so an accurate measurement of the remaining oxygen could be taken) had been damaged, shorted, then burned the insulation, causing the explosion.

On a sunny day (Fri, 25 Jan 2013 12:24:25 -0500) it happened snipped-for-privacy@attt.bizz wrote in :

13),

knowing,

in the

Must have read a different book... :-)

"The Apollo 13 malfunction was caused by an explosion and rupture of oxygen tank no. 2 in the service module." So it is written, so it must be.

Note the change in operating voltage for the tank heater from 28v to

65V.

Also, the fuel cell hold a rather small amount of oxygen. Had there been an explosion inside the fuel cell, it would not have been large enough to blow out the side of the service module.

--
Jeff Liebermann     jeffl@cruzio.com 
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Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

13),

cells

knowing,

in the

Mine was in the nonfiction section.

Jan only reads America or Windows bashing books, in the fiction section. He can't handle the truth.

versus NiMH running at 60. So they would need about 200 lbs of NiMH to replace the existing 60-pound battery. Of course the aircraft interface has to change, and, although straightforward, will be extensive rework.

Are these cells also subject to an operating temp range that would be exceeded (on the low end of course!) at altitude - as for instance Li-Ion would? If so, do they have battery warmers of some kind?

00 versus NiMH running at 60. So they would need about 200 lbs of NiMH to r eplace the existing 60-pound battery. Of course the aircraft interface has to change, and, although straightforward, will be extensive rework.

I know that Yuasa has at least one patent for handling charge regulation in low temperature environments, a circuit in shunt with the cell that divert s current into a cell heater cyclically and discussion on handling series s tacked cells. Apparently the variance in cell internal resistance spreads e nough in a stacked arrangement to create a potentially hazardous condition of overcharge. Assuming the overcharge safeguard fails, the second line of defense would b e something called the shut-down separator, a porous multi-ply membrane sep arating the electrodes designed to melt at pre-runaway temperatures and blo ck ion flow between electrodes. However:

The high voltage stability of the separator material at an elevated tempera ture following a successful thermally-induced shutdown is an important requ irement for series-connected cells. A high-impedance cell in a series strin g could be subjected to high voltages from the remaining cells, leading to a voltage breakdown of the separator caused by local currents through pinho le defects. Such a mechanism could result in localized heating and an inter nal short, which could ultimately result in thermal runaway and explosive cell failure. Acoording to a NASA summary NASA/TM?2009-215590.

And this is a 32V system with an unknown open circuit voltage at the outpu t of the charging electronics. There are always two additional internal saf eguards to try to prevent explosion beyond this point, a tear-away tab and pressure relief vent.

The problem with the separator approach is that the membrane becomes degrad ed though age, cycling, electrolyte decomposition products and who knows wh at else so that when it comes time to perform it doesn't work so well.

On a sunny day (Fri, 25 Jan 2013 16:35:32 -0500) it happened snipped-for-privacy@attt.bizz wrote in :

Apollo 13),

cells

knowing,

in the

As I do not buy books, mine came from online 4 sure. Maybe it was part of a biography of Von Braun, I liked it because it went much more into the sort of person he was than the usual NASA drivel. I would not trust a NASA publication if I got payed for it. It is all politics. Recently they did that old number again, they found carbon (signs of life) on mars, and then they disgraced the scientist that was all enthusiastic about it by canceling the press announcement, saying it was 'possibly carbon form earth'. They did the same number on Dr Levin:

who also had a positive on his mars experiment with Viking. He should have gotten a Nobel for that. NASA is a bunch of cowards who only do acrobatic media shows a few hundred km up, and say whatever 0bama or the current fuerer wants them to say. Why so afraid of life on other planets? Because it would me more intelligent than the pope? LOL

Apollo 13),

oxygen.

cells

knowing,

staring in the

If it's on the Internet it must be true!

Yet they have everything wrong.

Yet you believe what you read on the Internet. Amazing.

On Fri, 25 Jan 2013 11:25:38 -0500, Rich Webb wrote:

That does sound a bit far-fetched as worded, and he didn't actually claim it was an entire switchboard, just a switch, possibly a shore power disconnect or transfer switch, year 1942, put forward not as a story about the switch but as an explanation of why he kept the shipyard draft exemption rather than enlisting. When mentioning switchboards I was thinking of the open knife switch boards I have seen on the Fulton class sub tenders, in service through about 1980, where the knife switches were in a heavy screen enclosure with a normally locked door directly behind a dead-front switchboard, used to select which load (port/stbd sub feed or internal bus) a DC generator was to power before closing the generator main breaker - definitely used for sub battery charging. Only one dead- front breaker per generator was required with this arrangement, and no dead front switches. The shipyard may have used a similar arrangement for battery charging, so he might have been talking about a yard switch, but I got the impression the switch was on a sub, and clarification is no longer possible since he died in 06.

But on the subject of "you think *that* was stupid" sea stories, as told to me by a senior field service tech for a company I see is a supplier to the Dreamliner: They supplied a number of parts for the B-1B bomber including a deicer controller, whose specification called for the heater status bit to be set to 0 when the heater was turned on and 1 when off, opposite to all other status bits from equipment they had the spec for, while requiring a power on state of heater off, status bit 0. The engineer designing the controller was sure it was an error, and called Boeing, asking to speak to the spec writer. No, you can't talk to the engineering department at all was the reply, and after they spoke to everyone they knew how to contact at Boeing the final answer was "make it exactly like the spec or you will be found non-compliant and barred from future Boeing contracts". So they did, but also made and kept a couple extras with the status bit 1 when on, and put them on a shelf. Over a year later, after delivery of the first few planes, one finally encountered icing conditions, the heater turned on, and the flight computer reported heater failure. The aircraft was grounded and the supplier was called: "your defective controller grounded our plane - fix it fast!". The tech caught the next plane out with the alternate controllers, fixing the problem quickly, so while they were blamed for the problem at least they got credit for a fast fix.

I have no way of knowing if the above story is true, but it sounded good at the time, and I will not be surprised if there is a Boeing spec problem behind the battery fires and/or other Dreamliner electrical problems.

[snip good story]

Davide of Elithion was interviewed by the press and he said he thought there was a problem with the battery management system. They shortened his quote to say, "My gut feeling is that there was something wrong with the management here." ... :)

dreamliner-82626p7.html

ry-787s

Someone else asked Cesar Millan what he thought about the aggressive behavior of the lithium battery pack, and he said it "needed a good pack

leader". :)

Paul