Lithium battery packs for $30 each

Genesis

Sealed eh?

How much pressure is developed by a lithium fire, using the oxygen available in the sealed container, and what temperature is developed by said combustion?

Compare the above against the proof pressure of that enclosure from the inside (the opposite direction from which it was designed to take pressure) and compare the temperature of said fire with the melting point of acetyl.

Me thinks you want batteries that don't do that sort of thing when something goes wrong with them internally. That would exclude lithium primary cells from consideration as an appropriate power source.

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

RonMicjan

oh, and now we have spontanous battery combustion in a box that has about 3cc of airspace left in it with the battery taking up most of the space.

how about you doing the reasearch and tell us how many tadiran batteries have spontanously combusted in history???

rant: inciting to anger, rave, spewing... See Karl Denninger

Im going to read a book, why dont you start a nice game of hide and go **** yourself?

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Genesis

Here's one example; not a Tadirian battery but still a primary lithium cell...

CandlePowerForums - ROAR of the Pelican (CR123 Explosion during use, firsthand account)

And here's the picture....



Want the products of that in your loop? I didn't think so.

There is a lot of speculation about exactly why this happens, with some people claiming it can be prevented with pre-pack-build testing of the cells and others saying that this is BS. Primary lithium cells have an overcurrent device inside them to prevent thermal runaway from an external short but a short inside the cell due to a manufacturing fault cannot be protected against.

Odds of it happening? Low.

Outcome if it does happen?

You tell me.

Lithium primary cells should not be used in this application. There is little gain and while the risk of failure is low, the consequences if failure occurs are catastrophic.

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

RonMicjan

lets talk about differences:

the wonderful exploding flashlight

batteries in question, CR123 lithium
application, high current illumination
duration in said application 20 min-1 hour
heat generated, gets hot enough to burn your hand during NORMAL use
chances of rupturing a sealed cylinder good


the meg rebreather

batteries in question tadiran C cell lithium
application electronic monitoring and occasional solenoid activation and low current draw
duration of said cells in appliation ~ 200 hours
heat generated <almost nothing
chances of rupturing a sealed cylinder, less than extremely low

See, I actually have several flashlights of this type and I know they can get quite hot, I suggest that enquiring minds want to know how long that flashlight was left on before it melted down.

not exactly the same situation, you see. Interesting how you can find data and twist it to support your viewpoint de jeur.

I bet you were real fun to be married to. Write any letters to the Pope recently?

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Genesis

You didn't read the narrative did you? Yes, the thread was long but there was a lot of discussion and information there. Speculation appears to center around one of two potential failure modes, neither of which is protected against - either an internal short in the cell (manufacturing defect?) or a cell that either self-discharges faster than the other in the series string or was weaker to begin with, and through use was reverse-charged. Both of these faults appears to be a potential risk in this application and neither can be effectively controlled for. The latter (cell imbalance) is an inherent risk any time you have a series string and primary cells have no means of self-protection built into them.

There was apparently no indication of trouble before it blew. No appreciable heat buildup, no yellowing indicating that one cell was dead, etc.

As I said, odds of occurrance are very low.
However, the consequence of the occurrance, if it happens, is catastrophic.

Why take the chance when a suitable alternative without the risk exists? Is it really worth it when the original design offers 50-100 hours of dive time on a set of cells to start with?

I found that one with about 30 seconds of searching on the web. There are references in that thread to other failures, not all in flashlights (e.g. high current applications.)

If you want to run lithium primary batteries in this application be my guest. I personally believe that it is an extraordinarily bad idea for the reason I outlined, and the "mitigating factors" you cited (e.g. sealed lid on the compartment, etc) have no actual bearing on the risk being taken.

I bet if you told Tadirian that you intended to use their batteries in this application and describe in detail what you're doing and where they're going to be (e.g. in a compartment that will vent into a space with hyperbaric oxygen content if a failure occurs) they'd have a shizfit. Why not ask them and see if they approve of this intended use?

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

rdmmdr

RON

Quote from Woods Hole lithium fires

8.3.1 Lithium (Primary, Non-Rechargeable) Batteries

•

jeff h

Silent

Funny you've posted these pics tonight, I've just come across 2 video clips on YouTube where people have shown how nasty Lithium batteries can be.
Admittedly these 2 clips involve Lithium Ion & Lithium Polymer packs, but from what I can gather normal Lithium Primary batteries are even worse

<links here --->
So I suppose if we are going to use these types of batteries around water we need to be careful not to short or damage them...
Even when using/storing single AA cells for use in VR£ or HH for example.

Neil

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On the dark side everyone can hear you scream......

Sulac

have anyone tried this batteries [FONT='Times New Roman','serif']Lithium Polymer. [/font]