The battery protection circuit is composed of a protection IC and two power MOSFETs. The protection IC monitors the battery voltage and switches to an external power MOSFET in the event of overcharge and discharge. Its functions include overcharge protection, over-discharge protection, and overcurrent /Short circuit protection.

　　Overcharge protection device.

　　The principle of the overcharge protection IC is as follows: When an external charger is charging the sealed ups battery, to prevent the internal pressure from rising due to temperature rise, the charging needs to be stopped. At this time, the protection IC needs to detect the battery's voltage, and when it reaches (assuming the battery's overcharge point is), it will provide overcharge protection, which turns the power MOSFET off, and then cuts off charging.

　　Also, you must pay attention to the overcharge detection error caused by noise, so as not to be judged as overcharge protection. Therefore, the delay time needs to be set, and the delay time cannot be less than the noise duration.

　　Over-discharge protection device.

　　When the discharge is too much, the performance of the sealed ups battery will deteriorate due to the decomposition of the electrolyte, and the number of charging times will decrease. Using a sealed ups battery to protect the IC can avoid over-discharge and protect the battery.

　　Principle of over-discharge protection IC: To prevent the sealed ups battery from being over-discharged, suppose the sealed ups battery is connected to a load. When the sealed ups battery voltage is lower than its over-discharge voltage detector (assumed to be), it will be over-discharged. Protection, make the power MOSFET change from open-type to open-type, open-type discharge to avoid over-discharge, and keep the battery in a standby state, that is, only μA over-discharge current.

　　The battery protection circuit is composed of a protection IC and two power MOSFETs. The protection IC monitors the battery voltage and switches to an external power MOSFET in the event of overcharge and discharge. Its functions include overcharge protection, over-discharge protection and overcurrent / short circuit protection.