Though I’ve read about the potential for lithium ion batteries to bloat up when improperly charged, and even blogged here about it before, I’ve never actually seen one.
So it was pretty impressive to come across some pix and description of a swollen iPod Nano battery posted by David Kerry in his blog post iPod Cause of Death: Dangerous Battery. He figures it swelled to 3X its original size. (Check out the other great photos here too!)
After removing the iPod’s cover (which didn’t take long for obvious reasons), Kerry writes:
“What I was greeted with inside was rather shocking. It would appear as though my battery has swollen to around three times it’s original size and I’ve narrowly escaped a melting or exploding iPod. The swelling had not only wedged the select button permanently out rendering it, and the iPod useless, but also the front of the casing is actually cracked, a fact I had not initially noticed as it’s not easily visible on the white backing.
I’m going to attempt to bring this to Apple’s attention, as I believe this has been caused by a s***ty in-car charger, however I think Apple should be told just in-case there’s a small chance there’s a dodgy batch of two year old Nano’s out there about to start popping.”
Kerry says he never really got a satisfactory answer out of Apple — but I’d finger the in-car charger or a malfunction with the device’s internal charging circuits. There is a limit on how much currrent can be put through a lithium-ion cell. Exceeding it can produce a chemical reaction that causes the battery to swell up, as described in my blog post here.