Wired has a long long piece by John Hockenberry that covers thermal runaway, the thing that makes all those Sony Batteries explode.
It occurs when the touchy elements inside a Li-ion battery heat up to the point where the internal reaction accelerates, creating even more heat. In the case of a laptop flameout, the chemicals break out of their metal casing. Because lithium ignites when it makes contact with the moisture in the air, the battery bursts into flame.
Another fun fact from ther article is that "In the last 150 years, battery performance has improved only about eightfold (or less, depending how it's measured). The speed and capacity of silicon chips, of course, improves that much every six years."
But the best part is the info graphic sidebar that tell us that the future of the laptop battery involves multiple cells custom built for each component. Graphic of the futuristic after the jump...
The piece is long&mdash and surprisingly technical when it comes to explaining how batteries work. But man, I couldn't sit through it. On one hand, its nice to see Wired get back to its geek roots after a period where it just seemed like it was tech newbie-ish. On the other hand, the feature gets into a depth that even Popsci wouldn't attempt. Hardcore stuff.
Building a Better Battery [Wired]