Due to the chemical characteristics of lithium-ion batteries, during normal use, the internal chemical positive reaction of the mutual conversion of electric energy and chemical energy, but under certain conditions, such as overcharging, overdischarging and overcurrent will cause the battery A chemical side reaction occurs inside. When the side reaction is intensified, it will seriously affect the performance and service life of the battery, and may produce a large amount of gas, which will cause the internal pressure of the battery to rapidly increase and then explode, causing safety problems. Therefore, all lithium-ion batteries require A protection circuit is used to effectively monitor the charging and discharging status of the battery, and to shut off the charging and discharging circuits under certain conditions to prevent damage to the battery.

　　Lithium-ion battery protection circuit includes overcharge protection, overcurrent/short circuit protection and overdischarge protection, requiring high precision overcharge protection, low power consumption of the protection IC, high withstand voltage, and zero-volt rechargeability. The following article will introduce in detail the principles, new functions and characteristic requirements of these three protection circuits, which are of reference value for engineers to design and develop protection circuits.