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Old Jul 12, 2006, 07:35 PM
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Both of those make for very interesting reading hoppy.

I was especially interested to see the first one list this under Section VII Toxicological Information

Organic Electrolyte
・Acute toxicity:
LD50, oral - Rat 2,000mg/kg or more


Am Im reading that correctly that LD50 means "Likelyhood of Death" = 50% at that dosage???

Thanks!

Larry
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Old Jul 12, 2006, 11:22 PM
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LD50, 50% Lethal Dose

Definition
An LD50 value is the amount of a solid or liquid material that it takes to kill 50% of test animals (for example, mice or rats) in one dose.
This is closely related to the LDLo value which is the lowest dosage reported to have killed animals or humans.

LC50 (50% lethal concentration) is a related term used for gases, dusts, vapors, mists etc.


Soooooo, 2000mg/kg will kill 50% of the rats as I understand it.
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Old Jul 13, 2006, 12:11 AM
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So its safe to say this is potentially nasty stuff!

Thanks hoppy!

Larry
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Old Jul 13, 2006, 08:53 AM
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Quote:
Originally Posted by raptor22
I was arguing could happen that a while back. Elemental lithium burns like hell (hotter than magnesium), and burns alot faster under water. But everyone says "no, its only a lithium compound". Well, why does it burn white then? The anion is Li!

--Alex

Ho hum, here we go again...

There is no metallic Lithium in any Li-Po battery, and you can forget about that "plating" myth, as that amounts to milligrams.


What you are dealing with is LiCoO2 (Lithium Cobalt Dioxide) acting as a strong oxidizer under heat (producing oxygen), which then combines with the very flammable organic solvents used in the battery electrolyte.

It's the solvents, and then the battery "guts" that burn real nice!


The lack of flammable organic solvents, combined with the lack of an oxidizer, is what makes LiMn and similar cells so much safer.


Dat's the facts.
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Old Jul 13, 2006, 11:43 AM
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Expanding on that a little bit.....

LiCoO2 ---- Li + Co + O2

In a 100 g cell, about 30%, (30g) is LiCoO2. Complete decomposition to it's elements (which would not happen by the way) would only yield 10g of O2.
98/30 = 32/X X=10g of O2

A 100g LiPo cell contains about 40g more of less of organics and Al.
Each g of C requires 2.6g of O2 to burn.
Each g of H requires 8g of O2 to burn.
Each g of Al requires 8.8g of O2 to burn

It takes a lot of O2 to burn the chemicals in a LiPo cell, much more than the LiCoO2 can provide. Obviously there is enough energy being released to cause the cell to self destruct but to obtain the fireball seen in the videos, IMO, air must be avaiable. Which is why the LiPo Sack and Battery Bunkers work---no air, no fire.
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Old Jul 14, 2006, 11:15 PM
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Quote:
Originally Posted by hoppy
...Obviously there is enough energy being released to cause the cell to self destruct but to obtain the fireball seen in the videos, IMO, air must be avaiable. Which is why the LiPo Sack and Battery Bunkers work---no air, no fire.

As quoted in my reply, I was trying to point out why a Li-Po would "burn" under water, as described in the original post.

The oxidizer allows this, nothing else.


Sure, the big fireball is caused by the initial combustion rupturing the pouch, and then spreading the rest of the organics, etc. over a much larger surface area, but the initial "pop" and burn is entirely internal.
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