Lithium batteries have a high safety factor.

A lithium battery is a type of battery that uses lithium metal or a lithium alloy as the negative electrode material and an non-aqueous electrolyte solution. The development of lithium batteries can be traced back to the great inventor Thomas Edison. However, due to the highly reactive chemical nature of lithium metal, its processing, storage, and use impose extremely stringent environmental requirements, which has long hindered the widespread adoption of lithium batteries.

Lithium batteries offer advantages such as compact size, high specific energy, no memory effect, long cycle life, and the ability to operate at high voltages, while also exhibiting a lower self-discharge rate. Unlike nickel–cadmium and nickel–metal hydride rechargeable batteries, lithium batteries require careful attention to safety during charging and cycling to prevent performance degradation. Proper maintenance is critical to mitigate risks associated with overcharging, excessive charge/discharge cycles, overcurrent conditions, and short circuits. Consequently, battery management systems typically incorporate protective circuitry to ensure safe operation.

Due to the high specific energy of lithium batteries, the safety of rechargeable batteries cannot be guaranteed. When a battery is overcharged, the rise in temperature can lead to thermal runaway, causing excessive capacity; consequently, the electrolyte in lithium batteries decomposes, generating flammable gases and posing a risk of fire or rupture due to increased internal pressure. Conversely, during over‑discharge, the decomposition of the lithium‑battery electrolyte degrades the battery’s characteristics and performance, thereby reducing its service life.

The maintenance of lithium‑battery power circuits is designed to ensure safety and prevent performance degradation in cases of overcharging or excessive charge–discharge cycles. The battery‑management circuit consists of a management IC and two output‑side power MOSFETs. While monitoring the battery voltage, the management IC switches to the external output power MOSFETs to provide protection when the battery is subjected to overcharging or over‑discharging. This includes protection for charging batteries. The management IC’s functions encompass overcharge protection, over‑discharge protection, and protection against overcurrent and short‑circuit faults.