Why does the power bank catch fire or even explode

The cause of the power bank catch fire or even explode as below:

The reason is that manufacturers use inferior batteries and inferior wires, which can easily cause these problems after the mobile power supply overheats and short circuits.Therefore, when buying, try to choose a mobile power supply with a good reputation from a big brand, which is safe and secure.

Common cell classification:

18650 battery cell

18650 is a standard lithium-ion battery model set by SONY of Japan, the originator of lithium-ion batteries, in order to save costs. Among them, 18 means a diameter of 18mm, 65 means a length of 65mm, and 0 means a cylindrical battery.
There is another enhanced version of the 21700 battery, which is used in Tesla New energy vehicles.

Features: The most mature technology and low cost
Life span: Under full charge and discharge, it can reach about 400 times
Capacity: 2000-3000 mAh per section

Polymer battery cell
Features: Smaller size, can be made into any shape, and higher cost
Life span: Under full charge and discharge, it can reach about 700 times
Now mobile phone batteries use this kind of battery.