Carl-Daniel Hailfinger wrote:
If you control the embedded controller in charge of charging (sorry about the puns), you probably can fry a battery to the point where it starts burning. IIRC the OLPC EC code once had such problems. Then again, having a chipset spec will not help you at all when you try to mess with the EC.
That is why Li-Ion batteries have thermal protection circuitry. If they get too hot, the cells are open-circuited. There are several layers of protection in Li-Ion batteries to help protect them from ignition and explosion.
Here are a couple of links that get into more detail:
http://www.electronics-lab.com/articles/Li_Ion_reconstruct/
http://www.electronicproducts.com/ShowPage.asp?FileName=fa-nxp.mar2007.html
"Lithium will ignite and burn in oxygen when exposed to water or water vapors. It is the only metal that reacts with nitrogen at room temperature.
Lithium metal is flammable and potentially explosive when exposed to air and especially water, though it is far less dangerous than other alkali metals in this regard. The lithium-water reaction at normal temperatures is brisk but not violent. Lithium fires are difficult to extinguish, requiring special chemicals designed to smother them."
Great Google video here alkali+metals+water: http://video.google.com/videoplay?docid=1647759830306530002&q=alkali+met...
That is why car companies trying to launch vehicles that use Li-Ion batteries have spent so much effort on safety, since they may use thousands of cells in a single vehicle.
This is another reason why lithium iron phosphate or nanophosphate based cells are being used in new designs since they don't explode under extreme conditions.
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-Bari