Nexus 6 battery has been one of the problems of the smartphone. If it was just a situation of a weak battery life it would’ve been one thing, but the device has also technical concerns with the battery, where has been found a variety of situations of swelling, leading to pop open the rear cover.
In this particular user, it didn’t only swell. The battery really exploded, although, there was no fire. The device was lying not being used when this happened, and don’t cause any fire. The device was lying not used when this happened and not being charged. Not that the explosion of the battery should be caused by that.
Possibly, you never heard about the battery problems of the Nexus 6 because the smartphone is not very popular. But, this is not a insignificant issue that one can ignore and this should be taken seriously. Motorola will try to find some solution to fix it.