This battery pack applied special designed protection circuit: 

Over charge, Over discharge, Short circuit and over current protection.Prevent battery from fire and explosion.

2)Protection IC:

The protection IC with real time detection function: over charge ,such as over discharge ,over current and short circuit protection. It ensured battery security and stability.

3)Temperature detection switch :

This part was designed for high temperature protection of battery.

If the battery temperature up to 75±5℃, the temperature switch will cut-off the circuit to protect the cell.

4)Li-ion Cell:18650/2200mAh/ 3.7V  

5)MOSFET:

MOSFET,it keeps the voltage between the positive and negative conversion  in a stable situation.

6)Battery pack will packaged in sealed plastic case

http://www.m-battery.com