What`s Up with Laptop Batteries? - Current State of the Art
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Since lithium ion (Li-Ion) batteries replaced nickel cadmium (NiCad) batteries as the preferred battery for laptops a few years ago, they have been and remain the only commercially available option for laptops. You may still be able to find a few NiCad replacement batteries. Li-Ion batteries hold charge well, maintain their rechargeability, and have the longest life of any commercial batteries (though unfortunately, this isn't saying much).
The first lithium-based batteries created used metallic lithium for the anode. This was a safety problem. Lithium is one of the most electropositive of all elements, and therefore, also one of the most reactive. While the strong electropositivity of lithium gives lithium-based batteries their relatively long life, it can also be a safety hazard. To give you an idea of how reactive metallic lithium is, consider this: if you drop a chunk of lithium in a pail of water, it will violently ignite, with the release of large quantities of heat and explosive hydrogen gas.
Although they lasted longer than their predecessors, these first lithium batteries could not be sold because they had the potential to blow up someone's house. This problem was overcome by the advent of batteries that utilized safer lithium compounds and carbon for the anode instead of metallic lithium.
Since the first commercially available Li-Ion batteries were released by Sony in 1991, there have been improvements made in the safety of the batteries, but only minor progress in the area of battery life. Argonne National Laboratory announced in April 2008 that they have developed a Li-Ion battery with 30 percent longer life than the ones currently being sold. This is significant but not revolutionary, and in any case the battery is not on the market yet.
As it stands, even the longest-lasting of all of today's Li-Ion laptop batteries has a rated maximum life of only about 12 hours. I personally have never gotten anywhere close to the advertised maximum lifespan of a laptop battery, and neither has anyone else I know.
Although laptop batteries do last a bit longer now than they did a few years ago, this improvement has been mostly due to the use of microprocessors that consume less power rather than improvements to the batteries. There is hope on the horizon, however. In the next section we will look at a new battery technology that may mean you can eventually leave your charger at home!
Next: A New Development >>
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