I am designing a lithium-ion battery in my project but I am a little confused in regards to certain aspects of the protection circuit of lithium-ion batteries.I know about the different stages of charging a Li-Ion and you have to have a lithium charger IC to do the charging safely for you. If I understand it correctly you need to protect the battery against overcharge, overdischarge and overcurrent(shortcircuit) situations.
The Li-Ion battery(single cell, 1200mAh) I selected has a protection circuit of its own but the shutdown voltage is somewhere around 2.4V to 2.7V and the overcharge voltage is around 4.2/4.3V. My confusion lies around this 2.4V to 2.7V, I understood you shouldnt let Li-Ion discharge below 3.0V. My battery supplier and another source I found are saying it is better the batteries protection circuit should not be activated and they suggested I should also build an "extra/second" protection circuit on my PCB with a higher voltage like 3.0V so this circuit switches of the load first instead of the protection of the battery.
I cant confirm this in any other sources which seems strange to me for such an important aspect if there were correct. So my question basically is what the right design practice is and how this is often done. I know Seiko is pretty big in over/under voltage protection ICs but I can also imagine circuit with supervisors or op-amps.
An other question I have is in regards to a NTC thermistor for Li_ion batteries. (white or yellow wire in many batteries or packs)How important is this? When should I include this in my design? Because I sometimes see charger IC's with and without a connection for a thermistor.