The lithium battery protection board is meant to maintain the battery, which can effectively prevent the loss caused by unnecessary damage to the battery. So what is the principle of charging and discharging the battery maintenance board?

1. Discharge maintenance control principle of lithium battery protection board:
When the battery cell stops discharging through an external load, the cell voltage will slowly decrease, and the DW01 will monitor the cell voltage in real time through the R1 resistor. When the cell voltage drops to about 2.3V, DW01 will assume that the cell voltage has been In the over-discharge voltage state, immediately disconnect the output voltage of the first pin, so that the voltage of the first pin becomes 0V, and the switch tube in the 8205A is closed because there is no voltage on the fifth pin. At this time, the B- of the battery cell and the P- of the maintenance board are in a disconnected state. That is, the discharge circuit of the battery cell is cut off, and the battery cell will stop discharging. The maintenance board is in an over-discharged state from time to time. After the P and P- of the maintenance board have indirectly applied the charging voltage, DW01 will immediately stop the over-discharge state after B- detects the charging voltage, and output a high voltage at pin 1 again to turn on the over-discharge control tube in 8205A. That is, the B- of the battery cell and the P- of the maintenance board are reconnected, and the battery is directly charged by the charger.

2. Overcharge maintenance control principle of lithium battery protection board:
When the battery is normally charged by the charger, as the charging time increases, the voltage of the cell will become higher and higher. When the cell voltage rises to 4.4V, DW01 will think that the cell voltage is already in an overcharge voltage state. Then immediately disconnect the output voltage of the third pin, so that the voltage of the third pin becomes 0V, and the switch tube in the 8205A is closed because the fourth pin has no voltage. At this time, the B- of the battery cell and the P- of the maintenance board are in a disconnected state. That is, the charging circuit of the battery cell is cut off, and the battery cell will stop charging. The maintenance board is in an overcharged state from time to time. After the P and P- of the maintenance board discharge the load indirectly, the overcharge control switch is closed, but the forward direction of the internal diode is the same as the direction of the discharge circuit, so the discharge circuit can stop the discharge. When the voltage of the battery cell When the voltage is lower than 4.3V, DW01 stops the overcharge maintenance state and outputs high voltage at pin 3 again, so that the overcharge control tube in 8205A is turned on, that is, the battery B- and the maintenance board P- are connected again , The battery cell can stop normal charge and discharge.

If you want the battery maintenance board to stop working, you must remember the principle of overdischarge and overcharge of the battery maintenance board, which can reduce some battery problems and prevent damage to the battery.