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How can an iPod set your pants on fire -- literally?

        Tech | iPods

Quite a Charge
A lithium-ion battery
A lithium-ion battery

The reason behind all of the flame-ups has been traced back to the lithium-ion batteries commonly used in products like laptop computers, cell phones and, yes, iPods. Sony has recalled around 10 million of their batteries at a cost to the company of more than $400 million. Apple hasn't confirmed that the source of Danny Williams' iPod Nano fire was the battery, but the Nanos do use lithium-ion batteries.

So what's the problem with the batteries? Do they run on gasoline?

HowStuffWorks has already addressed the flaming batteries found in some laptops, and has explained how lithium-ion batteries work (it turns out that they don't run on gas). Declaring lithium-ion batteries as potentially hazardous is not new. So why do consumer electronic companies use them?

The answer is because the batteries give a lot of bang for the buck. They can hold up to six times the charge of a regular lead-acid battery (like the kind used in a car) for the same amount of battery weight, which makes them very valuable for making mobile devices like cell phones and laptops lighter. They are also rechargeable. The problem with lithium-ion batteries is that they degrade over the course of a few years. As the batteries degrade, the lithium and carbon that create the charge also degrade, and impurities form.

Sony says that the battery fires are caused by microscopic metal particles that come in contact with the other parts of the battery cell, causing a short circuit. The company says that on most occasions, the battery will shut down when a short circuit occurs. In some instances, however, the short circuit will cause an overheating of the battery cell, which could then erupt in flames [source: Sony].

Flaming consumer products add up to more than just threatened lives, lawsuits, recalls and lost revenue. It also further illuminates a painful fact that is well-known in the tech industry: Battery technology has not been able to keep up with the rapid progress of consumer electronics. As iPods get smaller, laptops get lighter, and cell phones get slimmer, the designs of these products are still held back by the bulky -- and, at times, dangerous -- batteries they use. This puts the tech industry in a catch-22: We live in an increasingly wireless world. Companies that produce wireless devices are forced to use batteries, and currently the best batteries for mobile devices are lithium-ion.

This catch-22 has spurred vigorous research into finding an improved battery technology. It has become a Holy Grail of power supply research in recent years. The company that can manufacture a lighter, safer, longer-lasting battery could take over the lion's share of the market. This is no secret, and many groups are competing to find a way to break through the battery barrier.

Read the next page to find out about a few of the projects that are being carried out to find the next generation of batteries.