Jul 12, 2013

What causes batteries to ignite?

The most recent “cell phone blows up” story made me wonder, what actually causes these batteries to ignite? Is there something some users are doing that make it it likely to occur, or is it really one of those luck of the draw events that just occurs randomly? The latest story I’ve seen was of a Galaxy S3 catching on fire in Switzerland, but it’s happened to iPhones, other Android devices and laptops of various manufacture over the years.

Why do batteries explode?

"Battery technology has been pushed over the years, but no incredible breakthroughs have come along. Instead, we see the same rechargeable cells packaged differently, shrunken down, and packed in more tightly. This makes more energy-dense batteries, but when something goes wrong it’s a much bigger deal.

A defective or improperly-handled battery can overheat, causing the cells to break open and result in a chain reaction of other cells rupturing. This is called thermal runaway, and it’s the cause of most battery explosions and, less dramatically, battery swelling. The defect can be a simple short circuit, or a design defect that improperly insulates individual cells from the heat of neighbors. That’s what causes cell phones and laptops to catch fire on rare occasions.

Any Li-ion battery has the potential to go up in flames, and that’s a product of its chemistry. Lithium is used in batteries as an anode because it has extremely high electrochemical potential. That is, lithium-ion moving to the electrode produces a lot of energy. Lithium’s low atomic weight is also useful in reducing the mass of batteries."
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