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Exploding lithiums??

R

Robert Morein

Jan 1, 1970
0
I like to watch movies with my laptop in my lap.
From what I've read about lithiums, this could be dangerous.
However, the only lithium accidents I've heard about involve cellphone
lithium polymers in plastic bags, presumably counterfeited in China.

Most laptops, on the other hand, use high grade Sony 16550 or 16850
cylindrical cells, which are hermetically sealed with conventional organic
liquid electrolyte. In terms of robustness and longevity, this particular
design is considered to be the Cadillac of lithiums.

Is anyone familiar with, or has anyone heard of, incidents when this type of
cell ruptured with explosive force, or enough heat to burn through the pack
casing?

One manufacturing criteria the cell is supposed to withstand is sawing
through, or crushing the case, without provoking an explosion.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Robert Morein
I like to watch movies with my laptop in my lap.

You need to consider the actual temperature of the bottom of the laptop
case, which is far more likely to cause you discomfort than the much
less probable battery explosion.
 
M

martin griffith

Jan 1, 1970
0
I like to watch movies with my laptop in my lap.
From what I've read about lithiums, this could be dangerous.
However, the only lithium accidents I've heard about involve cellphone
lithium polymers in plastic bags, presumably counterfeited in China.

Most laptops, on the other hand, use high grade Sony 16550 or 16850
cylindrical cells, which are hermetically sealed with conventional organic
liquid electrolyte. In terms of robustness and longevity, this particular
design is considered to be the Cadillac of lithiums.

Is anyone familiar with, or has anyone heard of, incidents when this type of
cell ruptured with explosive force, or enough heat to burn through the pack
casing?

One manufacturing criteria the cell is supposed to withstand is sawing
through, or crushing the case, without provoking an explosion.

try this

http://www.eet.com/article/printabl...=47900158&url_prefix=issue/fp&sub_taxonomyID=


martin

Serious error.
All shortcuts have disappeared.
Screen. Mind. Both are blank.
 
Q

qrk

Jan 1, 1970
0
I like to watch movies with my laptop in my lap.
From what I've read about lithiums, this could be dangerous.
However, the only lithium accidents I've heard about involve cellphone
lithium polymers in plastic bags, presumably counterfeited in China.

Most laptops, on the other hand, use high grade Sony 16550 or 16850
cylindrical cells, which are hermetically sealed with conventional organic
liquid electrolyte. In terms of robustness and longevity, this particular
design is considered to be the Cadillac of lithiums.

Is anyone familiar with, or has anyone heard of, incidents when this type of
cell ruptured with explosive force, or enough heat to burn through the pack
casing?

One manufacturing criteria the cell is supposed to withstand is sawing
through, or crushing the case, without provoking an explosion.

The lithium batteries of yore (1980s) had an interesting failure
mechanism when placed in housings for deep ocean use. Failure of a
battery pack (lots of batteries!) would cause the internal pressure of
the housing to rapidly increase which would blow the end cap off. This
"explosive" failure would only happen in sealed containers. The
company that did this testing for the Navy damaged a concrete bunker
in their tests. They also had a system fail in their production
facility which sent an end cap thru a few walls and ended up in the
VPs car. Fortunately, no one was hurt.
 
R

Robert Morein

Jan 1, 1970
0
John Woodgate said:
I read in sci.electronics.design that Robert Morein


You need to consider the actual temperature of the bottom of the laptop
case, which is far more likely to cause you discomfort than the much
less probable battery explosion.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I've heard about the legal cases regarding "laptop burns", and I laugh.
The brains of the victims must be a little unusual. Most of us readily sense
if something is uncomfortably warm.
IMHO, only a small minority of the population can screen out dangerous
stimuli.

Personally, I have never encountered a laptop bottom that was more than
uncomfortably warm.
I have never experienced a laptop with temperature elevated to the point
that tissue damage could occur.
On the other hand, explosive rupture of a battery pack close to the abdomen
could, concievably, be lethal.
 
J

Julie

Jan 1, 1970
0
Robert said:
I've heard about the legal cases regarding "laptop burns", and I laugh.
The brains of the victims must be a little unusual. Most of us readily sense
if something is uncomfortably warm.

It isn't an immediate burn, but a burn as a consequence of extended heated
contact, not unlike a sunburn.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Robert Morein
I've heard about the legal cases regarding "laptop burns", and I laugh.
The brains of the victims must be a little unusual. Most of us readily
sense if something is uncomfortably warm. IMHO, only a small minority of
the population can screen out dangerous stimuli.

AFAIK< the outcome of these incidents is still unknown. There may have
been faults.
Personally, I have never encountered a laptop bottom that was more than
uncomfortably warm. I have never experienced a laptop with temperature
elevated to the point that tissue damage could occur.

That's why I wrote 'discomfort'. my own laptop does get uncomfortably
warm, but it doesn't burn me.
On the other hand,
explosive rupture of a battery pack close to the abdomen could,
concievably, be lethal.

Yes, but the probability is probably lower than that of being fatally
kicked by a horse.
 
R

Robert Morein

Jan 1, 1970
0
John Woodgate said:
I read in sci.electronics.design that Robert Morein


AFAIK< the outcome of these incidents is still unknown. There may have
been faults.

That's why I wrote 'discomfort'. my own laptop does get uncomfortably
warm, but it doesn't burn me.


Yes, but the probability is probably lower than that of being fatally
kicked by a horse.
--
The two probabilities are not in the same universe of discourse because I
don't ride horses. OTOH, I am in close proximity with lithium packs.
 
G

Glen Walpert

Jan 1, 1970
0
The two probabilities are not in the same universe of discourse because I
don't ride horses. OTOH, I am in close proximity with lithium packs.

I am pretty sure John assumed you don't ride horses when he assigned
the lower probability to the exploding battery pack. All computer
lithium battery packs include a thermal fuse in direct contact with
one or more cells, so a cell explosion requires multiple simultaneous
failures including at least a low impedance short across the battery
and thermal fuse failure. I have never heard of even a single
occurrence of laptop battery pack explosion, and there are a lot of
them out there. On the other hand, I know several people who have
been kicked by horses :).
 
R

Rich Grise

Jan 1, 1970
0
It isn't an immediate burn, but a burn as a consequence of extended heated
contact, not unlike a sunburn.

I heard an urban legend about some guy who was driving at night in the
winter somewhere, and he was tired. So he pulled over, but just so he
wouldn't freeze, he left the engine idling, with the windows open enough to
let all the CO out. Unfortunately, he had fallen asleep with his foot right
up against the heater outlet, with hot air blowing directly off the heater
core onto his foot. The guy that told me this said that when the guy woke
up, his foot was completely cooked. It does sound plausible, after all,
especially if his feet were numb when he fell asleep.

<vaudevillian aside>
Didn't say whether or not he ate it. <rimshot>
</vaudevillian aside>

Cheers!
Rich
 
R

Robert Morein

Jan 1, 1970
0
Glen Walpert said:
I am pretty sure John assumed you don't ride horses when he assigned
the lower probability to the exploding battery pack. All computer
lithium battery packs include a thermal fuse in direct contact with
one or more cells, so a cell explosion requires multiple simultaneous
failures including at least a low impedance short across the battery
and thermal fuse failure.

The above is not true. Thermal runaway is possible within a single cell.
See:
http://www.ewh.ieee.org/cmte/PES-SBC/Downloads/sWM04_LithiumBatTech-Valence.pdf
 
R

Rich Grise

Jan 1, 1970
0
Glen Walpert said:
I am pretty sure John assumed you don't ride horses when he assigned
the lower probability to the exploding battery pack. All computer
lithium battery packs include a thermal fuse in direct contact with
one or more cells, so a cell explosion requires multiple simultaneous
failures including at least a low impedance short across the battery
and thermal fuse failure. I have never heard of even a single
occurrence of laptop battery pack explosion, and there are a lot of
them out there. On the other hand, I know several people who have
been kicked by horses :).
http://www.slackersguide.com/movies/Horse.mpg
 
G

Glen Walpert

Jan 1, 1970
0
The above is not true. Thermal runaway is possible within a single cell.
See:
http://www.ewh.ieee.org/cmte/PES-SBC/Downloads/sWM04_LithiumBatTech-Valence.pdf

OK, this article claims that it is a myth that protective devices will
prevent all battery explosions, and they are probably right. But they
only provide 2 examples of battery "explosions" including a single
laptop computer, and these incidents resulted only in minor burns.
Presumably the designed in cell overpressure venting features worked,
and these "explosions" consisted primarily of the venting of hot
gasses, which are not nearly as dangerous (or likely) as being kicked
by a horse. Even if the vent failed, the case of a lithium battery is
too thin to allow enough pressure to develop to cause penetration of
the laptop case when the cell ruptures. "Possible" is quite different
than "probable", and the "explosion" of a lithium cell is quite
different than the explosion of a roadside bomb in Iraq! But if you
are really concerned about the slight possibility of second degree
burns, how about a nomex lap pad?
 
A

Al

Jan 1, 1970
0
Glen Walpert said:
OK, this article claims that it is a myth that protective devices will
prevent all battery explosions, and they are probably right. But they
only provide 2 examples of battery "explosions" including a single
laptop computer, and these incidents resulted only in minor burns.
Presumably the designed in cell overpressure venting features worked,
and these "explosions" consisted primarily of the venting of hot
gasses, which are not nearly as dangerous (or likely) as being kicked
by a horse. Even if the vent failed, the case of a lithium battery is
too thin to allow enough pressure to develop to cause penetration of
the laptop case when the cell ruptures. "Possible" is quite different
than "probable", and the "explosion" of a lithium cell is quite
different than the explosion of a roadside bomb in Iraq! But if you
are really concerned about the slight possibility of second degree
burns, how about a nomex lap pad?

Great, execpt in the USA, two is two too many. We ban items when 6
people get hurt over a 5 year period even though millions have used them
safely.

Al
 
R

Robert Morein

Jan 1, 1970
0
Glen Walpert said:
..pdf

OK, this article claims that it is a myth that protective devices will
prevent all battery explosions, and they are probably right. But they
only provide 2 examples of battery "explosions" including a single
laptop computer, and these incidents resulted only in minor burns.
Presumably the designed in cell overpressure venting features worked,
and these "explosions" consisted primarily of the venting of hot
gasses, which are not nearly as dangerous (or likely) as being kicked
by a horse. Even if the vent failed, the case of a lithium battery is
too thin to allow enough pressure to develop to cause penetration of
the laptop case when the cell ruptures. "Possible" is quite different
than "probable", and the "explosion" of a lithium cell is quite
different than the explosion of a roadside bomb in Iraq! But if you
are really concerned about the slight possibility of second degree
burns, how about a nomex lap pad?
All good points. The purpose of the post was to determine if events had
occurred similar to http://www.cdc.gov/niosh/face9939.html involving lithium
sulfur primary batteries.
These batteries do pose an explosion hazard. Imagine if the batteries in the
above case had been in a device cradled in a person's lap!
Perhaps the venting characteristics of LiIon batteries are different from
lithium sulfur primary batteries.
 
M

Mark W. Lund, PhD

Jan 1, 1970
0
Yes, lithium ion has different pyrotechnic properties than
lithium sulfur dioxide or lithium thionyl chloride. The latter
two types use metallic lithium and electrolyte that is the
actual reactant. Get them hot enough to melt the lithium
and you will get a big boom. These have about 1/3 the energy
density of TNT.

Lithium-ion doesn't use lithium metal, but lithium compounds,
the energy density is much less and the boom turns out to be
a pop and a fire.

Best regards
mark

All good points. The purpose of the post was to determine if events had
occurred similar to http://www.cdc.gov/niosh/face9939.html involving lithium
sulfur primary batteries.
These batteries do pose an explosion hazard. Imagine if the batteries in the
above case had been in a device cradled in a person's lap!
Perhaps the venting characteristics of LiIon batteries are different from
lithium sulfur primary batteries.

--
----------------------------------------------------------------------
Mark W. Lund, PhD ** Battery Chargers
CEO ** Bulk Cells and Custom Battery Packs
PowerStream Technology ** Custom Power Supplies
140 S. Mountainway Drive ** DC/DC Converters
Orem Utah 84058 ** Custom UPS
http://www.PowerStream.com ** Engineering, manufacturing, consulting
 
G

Glen Walpert

Jan 1, 1970
0
On Thu, 7 Oct 2004 23:07:41 -0400, "Robert Morein" >"Glen Walpert"
All good points. The purpose of the post was to determine if events had
occurred similar to http://www.cdc.gov/niosh/face9939.html involving lithium
sulfur primary batteries.
These batteries do pose an explosion hazard. Imagine if the batteries in the
above case had been in a device cradled in a person's lap!
Perhaps the venting characteristics of LiIon batteries are different from
lithium sulfur primary batteries.

Looks like the user called it an exolosion and the battery
manufacturer called it one of 4 venting incidents in 144,000 cells,
which would be 1 incident per 9000 of their 4-cell batteries. Too bad
they don't reveal what the cells were, but they look to be fair sized,
perhaps D size similar to a Tadiran TL5930 with a capacity of about 19
AH at 3.6v nominal, but probably the less safe spiral wound
construction from another mfgr., having lower internal impedance which
increases the heating rate in the event of a short.

I think that the venting characteristics of these batteries differ
from the venting characteristics of your Sony 16550 laptop battery
cells in that the Sony cells are probably more reliable (but lacking
actual data to back that hunch which based on the large number of
laptop computers out there and the small number of incidents that I
have heard of), and they are definitely smaller, storing quite a bit
less electrolyte to potentially boil as the cell overheats, and they
contain a lot less energy to heat that electrolyte up with their
measly ~2 AH capacity. So in the unlikely event a cell should vent in
your lap you will most likely wind up with no worse than a minor
nusiance burn (depending on how fast you react and how willing you are
to toss that expensive laptop on the floor).

One would hope that the battery case and cover would be designed to
retain the cells during a venting incident (unlike the Medtronic AED
battery case/cover shown in your link), but for some reason I find
myself recalling the famous Ford Pinto gas tank explosions and their
leaked management memo with the calculation that it would be cheaper
to pay for the expected couple dozen additional immolated vehicle
occupants than to fix the gas tank design so it wouldn't explode in an
accident. Perhaps the nomex pad is not such a bad idea :).
 
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