I don't know whether your battery protection circuit is in the research and development stage or whether it is a purchased finished lithium battery. If you are testing a lithium battery protection board in the research and development stage, if the capacity is relatively small and the overcurrent point is relatively low, you can first directly use an electronic load to conduct current, and then use the electronic load to make a short circuit. If there is no problem, you can actually connect a fuse in series and use a wire to short directly. If the battery capacity is large and the overcurrent point is very high and the electronic load cannot measure the overcurrent point, then you need to remove the power mos and solder a resistor to the ds of the power mos to simulate the voltage drop required for overcurrent. or a short circuit. Usean oscilloscope to observe the mos. Check whether the g pole potential change and tube delay are normal, and then estimate the overcurrent point according to the actual internal resistance of the mos on the protection board. Finally, a slow blow fuse is used to short the circuit. In case of short circuit, protection must be taken, at least the power mos must be blocked with objects. To avoid short circuit failure.
Good luck!
If you charge the battery directly, will the protection board be disconnected?
I don't know if your battery protection circuit is in the research and development stage or if it is an outsourced finished lithium battery. If it is in the research and development stage, test the lithium battery. If the battery protection board has relatively low capacity and relatively low overcurrent point, you can first usedirectly an electronic load to conduct the current, then use the electronic load to make a short circuit. If there is no problem, you can actually connect a fuse in series and use a wire to short directly. If the battery capacity is large, the overcurrent point is very high and the. The electronic load cannot measure the overcurrent point. Next, you need to remove the power MOS, solder a resistor to the DS of the power MOS to simulate the required voltage drop in the event of an overcurrent or short circuit, and use an oscilloscope to observe the potential changes of the G electrode .of the MOS tube and check whether the delay is normal, then estimate the overcurrent point according to the actual internal resistance of the MOS on the protection board. Finally, use a slow blow fuse in the circuit to actually short it. In the event of a short circuit, you must takee good protection, cover at least the power MOS with something to avoid short circuit failure.
The protection board will disconnect if the battery. is charged directly.The battery protection board will disconnect the power supply and battery when the battery voltage is lower than 2.5V. When charging, the battery protection settings are enabled.
The purpose of connecting batteries in parallel is to increase capacity. The installed protection board will only prevent the overall voltage from being too high or too low, overshooting or over-discharging, but will not achieve the purpose of balancing the battery voltage. Connection of batteries in parallel. It is necessary that the voltage difference between the two batteries is 5mV and the capacity difference is 20mah. Otherwise, during use, the battery at low voltage and low capacity will affect the opposing battery and fail to do so. achieve the goal of increasing capacity.
Protection board principle:
Lithium battery protection boards have different circuits and parameters depending on the integrated circuit used, voltage, etc. For commonly used protection, Seiko's 8261 series has better accuracy. Of course, the price is also higher.
These are all produced in Taiwan. The domestic secondary market mainly uses DW01+ and CS213. The following uses the DW01+ with MOS tube to explain the normal operation process of the lithium battery protection board.
When the cell voltage is between 2.5V and 4.3V, pins 1 and 3 of the DW01 output a high level equal to the supply voltage.Voltage, the voltage of the second pin is 0 V.
At this point, the voltage of pins 1 and3 of the DW01 will be added to pins 5 and 4 of the 8205A respectively. The two electronic switches of the 8205A have their G pole connected to the voltage of the DW01, therefore. Both are in the conductive state, that is, both electronic switches are in the open state, at this time the negative electrode of the battery core is directly connected to the P terminal of the protection board, and the protection board has voltage output. .