Mobile Computing: Laptop Battery Safety

Is a fire extinguisher the next must-have notebook accessory?

On August 14, Dell announced a massive recall of 4.1 million notebook batteries because of a potential fire hazard. The lithium ion batteries, made by Sony, were installed in Dell notebooks sold between April 2004 and July 18, 2006; 2.7 million were sold in the United States.

Soon after, Apple announced a recall of 1.8 million lithium ion batteries for its iBook and PowerBook notebooks. These batteries were also made by Sony.

Apple's announcement was followed by one from Panasonic, which said it was recalling 6000 laptop battery packs because of potential overheating. Panasonic's recall only affects laptops shipped to Japan. The company wouldn't identify the battery manufacturer.

Despite these high-profile recalls, the hazard potential shouldn't be exaggerated. For example, Dell recalled millions of battery packs because of six incidents reported since December 2006.

Of course, nobody wants to be one of the unlucky few, and you're probably wondering what the hubbub is about. This week I'll answer questions about the risks of lithium ion batteries. Next week I'll offer tips on what you can do to protect yourself, plus give you an update on what's being done to reduce or eliminate such risks in the future.

Why Would a Battery Overheat?

Most portable electronics today, such as notebooks, cell phones, and MP3 players, are powered by lithium ion batteries. Compared to the earlier generation of nickel metal hydride batteries, lithium ion batteries have a better power-to-weight ratio, hold a charge longer, have a longer usable life, are lighter, and don't have the "memory effect," which can cause a battery that's regularly "topped off" to prematurely fail. Lithium ion batteries are also inexpensive to manufacture.

The downside: Lithium ion batteries contain an electrolyte (lithium salt) dissolved in a highly flammable solvent. If the batteries short-circuit, they could overhead--causing failure, and sometimes making them erupt in flames.

What Causes a Battery to Short-Circuit?

For one thing, there's the possibility of manufacturing defects. In the case of the Sony batteries involved in the Dell recall, Dell had received customer reports of laptops overheating and catching fire. A Sony spokesperson said that "under certain rare conditions," there's a chance that the Dell batteries being recalled could overheat or catch fire due to a possible manufacturing defect.

Then there are things users do that can cause problems. Placing multiple lithium ion batteries together in a bag, without covering their contact points, can cause shorting and sparks if the contact points rub together. Also, exposing a notebook, mobile phone, or other electronic device containing lithium ion batteries to extreme heat could cause its battery to overheat and possibly catch fire.

How Big Is the Risk?

Statistically, the chances your laptop battery will catch fire are infinitesimally small. Since 1993, the Consumer Product Safety Commission has recorded 339 cases of overheated lithium and lithium ion batteries in portable electronics. Of those, 176 were laptops, according to the commission. No serious injuries or deaths have been reported.

Nonetheless, several high-profile incidents have raised awareness of the dangers. For example, in June 2006, a Dell laptop caught fire during a conference in Osaka, Japan. Reports of the flame-out spread quickly on the Internet.

What About Other Batteries?

Sony, the maker of the laptop batteries that Dell recently recalled, also makes batteries for Apple, Hewlett-Packard, Lenovo, and other companies. Other than Apple, none of these companies have recently recalled any Sony batteries, as of this writing.

Battery recalls haven't been limited to laptops. In 2005, lithium ion batteries in a Nikon digital camera, a Belkin GPS navigation system, and a Polaroid portable DVD player were recalled, according to the Consumer Product Safety Commission. In fact, until recently, the largest safety recall of a consumer electronics product had been in October 2004 for 1 million lithium ion batteries used in Kyocera cell phones.

Check back next week for tips on protecting both your electronics and yourself.

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