|Jul 12, 2006, 07:35 PM|
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
LD50, oral - Rat 2,000mg/kg or more
Am Im reading that correctly that LD50 means "Likelyhood of Death" = 50% at that dosage???
|Jul 12, 2006, 11:22 PM|
LD50, 50% Lethal Dose
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.
|Jul 13, 2006, 08:53 AM|
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.
|Jul 13, 2006, 11:43 AM|
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.
|Jul 14, 2006, 11:15 PM|
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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