why is this circuit attached to samsung batteries

[bowwowbgk]

AMOTECH C11DSSDOMOO2-Rev.03 this is the code on the circuit when i removed it from the back of the battery.#samsung X3.

 

[anon(632115)]

It's NFC

 

[Mycrossover]

Lithium batteries are fussy. If they are discharged below a certain voltage they suffer permanent damage and cannot come back. If they are over charged, they overheat and can catch fire. If the current demand is too high, like a short circuit in your X3, they can be damaged or catch fire. That circuit board is in there to protect you, the battery and your X3. It disconnects the battery if any of the above conditions occur.