Jiali intelligent control

　　Lithium battery protection board is intended 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. Principle of discharge and maintenance control of lithium battery protection board:

When the battery cell stops discharging through the external load, the voltage of the battery cell will gradually decrease. At the same time, 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 think that the cell voltage has been In the state of over-discharge voltage, the output voltage of pin 1 is immediately disconnected, so that the voltage of pin 1 becomes 0V, and the switch tube in 8205A is turned off because there is no voltage on pin 5. 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 cell is cut off, and the cell will stop discharging. The maintenance board is in an overdischarged state and persists from time to time. After the P and P- of the maintenance board are connected to the charging voltage indirectly, DW01 immediately stops the over-discharge state after detecting the charging voltage through B-, and outputs a high voltage on the 1st pin again, so that the over-discharge control tube in the 8205A is turned on. That is, the B- of the battery cell and the P- of the maintenance board are reconnected, and the battery cell is directly charged by the charger.

Second, the overcharge maintenance control principle of the 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 voltage of the cell rises to 4.4V, the DW01 will think that the voltage of the cell has been in the state of overcharge voltage. The output voltage of the 3rd pin is immediately disconnected, so that the 3rd pin voltage becomes 0V, and the switch tube in the 8205A is turned off because the 4th 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 and persists from time to time. After the P and P- of the maintenance board are directly connected to the discharge load, although the overcharge control switch is turned off, the positive direction of the internal diode is the same as the direction of the discharge circuit, so the discharge circuit can stop the discharge. When it is placed below 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 B- of the battery cell and the maintenance board P- are reconnected , the battery can stop the normal charge and discharge.

　　If you want to stop the battery protection board from working, you must remember the principle of over-discharge and over-charging of the battery protection board, which can reduce some battery usage problems and prevent battery damage from causing losses.