Dynaverse.net
Off Topic => Engineering => Topic started by: Nemesis on November 28, 2007, 08:08:32 pm
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Link to full article (http://www.iht.com/articles/ap/2007/11/28/asia/AS-GEN-SKorea-Mobile-Phone-Explosion.php)
SEOUL, South Korea: An exploding cell phone battery may have killed a South Korean man, police said Wednesday, although the phone's manufacturer said it was highly unlikely.
The man, identified only by his family name Suh, was found dead at his workplace in a quarry Wednesday morning and his mobile phone battery was melted in his shirt pocket, a police official in Cheongwon, 135 kilometers (85 miles) south of Seoul, told The Associated Press.
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Yup, it can happen. Lithium Ion batteries in most cases use cobalt oxide, which if heated beyond 140degrees F can result in "thermal runaway" where the material begins to oxidize and provide massive amounts of fuel and heat, often sparking a fire. Once the chemical reaches the thermal runaway point, it begins to self heat ... it can be very dangerious. Not so much with cell phone batteries, but for larger laptop batteries the individual cells can explode as the heat and pressure rupture the casing, which of course, spreads the fire to the next cell in the battery making the fire hotter and more intense.
All unlikley to happen of course. Unless you damage the battery, or short out its contacts, or otherwise abuse the battery (like subjecting it to very hot temps) then this really isn't a worry.
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Turns out a coworker accidently hit him with a piece of machinery and then blamed the phone.
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Modern Lithium ion batteries utilize multiple redundant safety circuits, including overvoltage, overcurrent, and a physical pressure relief cap.
Flaws and true "thermal runaway" events are extremely rare, on the order of less than 1 in one million. In fact 1 in one million would be viewed as unacceptable by all manufacturers.
Typical QA testing includes not only a battery (punny!) of electrical tests, but also physical drop & impact.
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Modern Lithium ion batteries utilize multiple redundant safety circuits, including overvoltage, overcurrent, and a physical pressure relief cap.
Flaws and true "thermal runaway" events are extremely rare, on the order of less than 1 in one million. In fact 1 in one million would be viewed as unacceptable by all manufacturers.
This year Sony had a run of exploding batteries get in the news.