Specific decomposition of the principle of lithium battery protection board

The reason why lithium battery (rechargeable type) needs to be protected is determined by its own characteristics. Because the material of the lithium battery itself determines that it cannot be overcharged, overdischarged, overcurrent, short-circuited, and ultra-high temperature charging and discharging, the lithium battery components of the lithium battery will always appear with an exquisite protection board and a current fuse. The protection function of lithium battery is usually completed by the protection circuit board and current devices such as PTC. The protection board is composed of electronic circuits, which can accurately monitor the voltage of the cell and the charging and discharging circuit at all times under the environment of -40℃ to +85℃. Current, control the on and off of the current loop in time; PTC guards against severe damage to the battery in a high temperature environment. The general lithium battery protection board usually includes control IC, MOS switch, resistor, capacitor and auxiliary devices FUSE, PTC, NTC, ID, memory and so on. Among them, the control IC controls the MOS switch to turn on under all normal conditions to make the cell and the external circuit conduct, and when the cell voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the cell’s Safety. When the protection board is normal, Vdd is high, Vss and VM are low, DO and CO are high. When any parameter of Vdd, Vss, VM is changed, the level of DO or CO will be Changes. 1. Overcharge detection voltage: Under normal conditions, Vdd gradually increases to the voltage between VDD and VSS when the CO terminal changes from high level to low level. 2. Overcharge release voltage: In the charging state, Vdd gradually decreases to the voltage between VDD and VSS when the CO terminal changes from low level to high level. 3. Overdischarge detection voltage: Under normal conditions, Vdd gradually decreases to the voltage between VDD and VSS when the DO terminal changes from high level to low level. 4. Overdischarge release voltage: In the overdischarge state, Vdd gradually rises to the voltage between VDD and VSS when the DO terminal changes from low level to high level. 5. Overcurrent 1 detection voltage: In the normal state, VM gradually rises to the voltage between VM and VSS when DO changes from high level to low level. 6. Overcurrent 2 detection voltage: In the normal state, VM rises from OV to the voltage between VM and VSS when the DO terminal changes from high to low at a speed of 1ms or more and 4ms or less. 7. Load short-circuit detection voltage: Under normal conditions, VM starts from OV and rises to the voltage between VM and VSS when the DO terminal changes from high level to low level at a speed of 1μS or more and 50μS or less. 8. Charger detection voltage: In the over-discharge state, VM gradually decreases with OV to the voltage between VM and VSS when DO changes from low level to high level. 9. Current consumption during normal operation: Under normal conditions, the current flowing through the VDD terminal (IDD) is the current consumption during normal operation. 10. Over-discharge current consumption: In the discharge state, the current (IDD) flowing through the VDD terminal is the over-current discharge current consumption. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: How to customize lithium battery packs?