Ejector
21st Aug 2006, 13:22
This is a little off topic. In a email I was sent regarding a Dell recall this was also in it. !!!!!!emmmmm good thing for recalls hey.
So why is this happening now?
Lithium ion batteries (of any construction type) contain lithium which is pretty volatile in certain circumstances. Heat it too much and it ignites and produces a lot of heat and flame. Get it wet and stand back. Damage or drop the casing and boom. Short circuit it and flash.
Lithium ion batteries use cobalt oxide, which has a tendency to undergo "thermal runaway" - when you heat this material up, it can reach an onset temperature that begins to self-heat and progresses into fire and explosion. For example leaving a notebook in a locked car where temperatures can easily reach 60-80 degrees C (with an outside temperature of only 30 degrees C) is a perfect way to start a fire.
If you rapidly discharge a Lithium ion battery it can also result in overheating of the battery, rupture, and even explosion. Lithium-thionyl chloride batteries are particularly capable of this type of discharge. Consumer batteries usually incorporate over-current or thermal protection or vents in order to prevent explosion. Because of these risks, shipping and carriage of lithium batteries is restricted in some situations, particularly transport by air. Now that lithium-ion powered laptops and MP3 players have become favourite carry-ons transportation officials are re-evaluating the safety risks posed on airliners and whether tighter restrictions are required.
In 1999 a pallet of Lithium camera batteries caught fire on the ground at Los Angeles International Airport after it was inadvertently dropped. The FAA Tech Center undertook its examination of this more dangerous scenario. They found:
* The original fire was caused by dropping only - physical damage
* A relatively small fire source was sufficient to start a lithium battery fire.
* The heat from a single battery on fire was sufficient to ignite adjacent batteries.
* The outer plastic coating on the batteries easily melted, fusing the batteries together, adding to the intensity of the fire.
* The chain reaction ignition continued until all batteries were consumed.
* The molten lithium burned explosively, spraying white-hot lithium to a radius of several feet as the batteries bounced around.
* The duration of the peak temperature increased with the number of batteries, reaching as high as 1,400[degrees] F (as a matter of interest, the melting temperature of aluminium is around 1,200[degrees] F).
* Halon fire-suppressing agent, injected in sufficient concentration to "knock down" a fire, proved totally ineffective, even when injected after just the first battery had caught fire. Nor did it have any effect on the peak temperature. The fire continued as if Halon were not present.
* Lithium batteries catch fire with explosive force. When they burst, they create a pressure pulse. The eight-battery test produced a pressure pulse of 1.8 psi, and the 16-battery test generated a 2.6 psi pulse.
So why is this happening now?
Lithium ion batteries (of any construction type) contain lithium which is pretty volatile in certain circumstances. Heat it too much and it ignites and produces a lot of heat and flame. Get it wet and stand back. Damage or drop the casing and boom. Short circuit it and flash.
Lithium ion batteries use cobalt oxide, which has a tendency to undergo "thermal runaway" - when you heat this material up, it can reach an onset temperature that begins to self-heat and progresses into fire and explosion. For example leaving a notebook in a locked car where temperatures can easily reach 60-80 degrees C (with an outside temperature of only 30 degrees C) is a perfect way to start a fire.
If you rapidly discharge a Lithium ion battery it can also result in overheating of the battery, rupture, and even explosion. Lithium-thionyl chloride batteries are particularly capable of this type of discharge. Consumer batteries usually incorporate over-current or thermal protection or vents in order to prevent explosion. Because of these risks, shipping and carriage of lithium batteries is restricted in some situations, particularly transport by air. Now that lithium-ion powered laptops and MP3 players have become favourite carry-ons transportation officials are re-evaluating the safety risks posed on airliners and whether tighter restrictions are required.
In 1999 a pallet of Lithium camera batteries caught fire on the ground at Los Angeles International Airport after it was inadvertently dropped. The FAA Tech Center undertook its examination of this more dangerous scenario. They found:
* The original fire was caused by dropping only - physical damage
* A relatively small fire source was sufficient to start a lithium battery fire.
* The heat from a single battery on fire was sufficient to ignite adjacent batteries.
* The outer plastic coating on the batteries easily melted, fusing the batteries together, adding to the intensity of the fire.
* The chain reaction ignition continued until all batteries were consumed.
* The molten lithium burned explosively, spraying white-hot lithium to a radius of several feet as the batteries bounced around.
* The duration of the peak temperature increased with the number of batteries, reaching as high as 1,400[degrees] F (as a matter of interest, the melting temperature of aluminium is around 1,200[degrees] F).
* Halon fire-suppressing agent, injected in sufficient concentration to "knock down" a fire, proved totally ineffective, even when injected after just the first battery had caught fire. Nor did it have any effect on the peak temperature. The fire continued as if Halon were not present.
* Lithium batteries catch fire with explosive force. When they burst, they create a pressure pulse. The eight-battery test produced a pressure pulse of 1.8 psi, and the 16-battery test generated a 2.6 psi pulse.