Do all rechargeable lithium batteries require circuit protection?

Do all rechargeable lithium batteries require circuit protection?

Yes, all commercial rechargeable lithium batteries (packs) must be equipped with circuit protection. Only in extremely rare special experimental scenarios might bare cells be temporarily unprotected, but this poses an extremely high safety risk.

The electrochemical properties of lithium batteries necessitate protective measures.

Lithium is highly reactive, making lithium batteries sensitive to charging and discharging conditions (voltage, current, temperature):

Overcharging: Causes decomposition of the cathode material and oxidation of the electrolyte, generating significant heat and gas, leading to thermal runaway (bulging, fire, explosion);

Over-discharge: Causes metallic lithium to precipitate from the negative electrode, forming lithium dendrites that pierce the separator, resulting in internal short circuits;

Overcurrent/Short circuit: High currents generate instantaneous high temperatures, directly burning out the cell or even causing combustion.

The core function of the protection circuit is to interrupt abnormal circuits: implementing overcharge, over-discharge, overcurrent, short circuit, and temperature protection to prevent hazards.