On Jan 6, 2006, at 3:39 PM, David VanHorn wrote:

>> I did the "drive a nail through an Li-poly battery" "experiment"
>> the other night.  Very impressive!
>
> All the lithium batteries I have, that are not in actual use,
> are kept in the fridge.

Um.  that's supposed to help how?  I guess the interior of a
fridge is relatively fireproof...
>
> For charging experiments, I have a chamber made of 1/4" Plexiglas.
>
The usual failure mode involves fumes and (rather violent) fire,
rather than explosion and shrapnel.  I would worry that your
plexiglas would make a fine fuel for expanding the fire...


Maybe this is what I can use my old dishwasher for.  Although I'm
not so sure that storing large quantities together is such a great
idea; thermal runaway is prone to jumping from one to another, I'm
led to believe...

(Li-ions are exciting.  First, the electrical energy density is
pretty high.  Next, the electrolyte is flammable.  And finally,
some of the components (Li and Cobalt oxides?) are prone to doing
a thermite-like reaction when the temperature gets high enough.)

http://www.valence.com/SafetyVideo.asp
http://www.a123systems.com/html/tech/safety.html#

(these are videos from companies that market "safer" alternatives,
so they're a bit suspect.  Nevertheless, they are pretty close
to the results from my own experiment (but, um, "quicker."))

BillW
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist