In the last few weeks we've had the pleasure of twice witnessing a bizarre phenomenon – iPhone battery bloat. Due to gas build-up, some old iPhone batteries can swell up to such an extent that they damage the phone. On this customer's phone, the spectacularly iPhone bloated battery even pushed the screen assembly out from the back case. Fortunately, there was minimal damage and a battery replacement restored the iPhone to fully working order. It looks like it's an issue that Apple is well aware of and is tackling through engineering changes.