[thailen]

Afraid it might explode. Is this a battery or a device problem and would replacing the battery fix it? If not, what should I do?

[B. Diddy]

How warm? Do you have a battery monitor app that can report the battery temp? In general, batteries can get upwards of 120F without much danger.

What is the tablet doing when it's that warm? Are you playing graphics-intense games? Installing a bunch of apps?

A corrupt SD card can cause the CPU to work overtime, so try unmounting the card in Settings>Storage​ and removing it.

[thailen]

I don't have an SD card, because I used two cards and they both broke for no apparent reason. We play 4pics. Maybe 10 apps. Not 120 degrees, just warm.

[B. Diddy]

All devices get warm to a certain degree with normal usage, and they get hotter if the CPU usage is more intense. You should be fine.

[clevin]

if it gets hot (not warm, i mean getting hot to touch) during normal use (not during update process), I would reboot the phone, if once doesn't work, try twice.