CRC…. Here are a couple of links that should help you understand some basics (& more) about batteries, LiIon especially.
Take your time & read them, if you have questions please ask. Help is available. 
Honestly… it IS NOT all that complicated. 
…….
Lithium-ion battery safety 101
Read intro here at Battery U.
- Battery University
https://batteryuniversity.co
START HERE on Battery University
- Part One: Basics You Should Know
BU-001: Sharing Battery Knowledge - Battery University