1. Test method for short circuit protection
A. Connect the BMS protection board to the cell and voltmeter as shown below and activate it. The no-load output voltage of P+P- should be equal to the cell voltage of B+B-.
B. Short-circuit P+P- with a wire for more than 1s, the voltmeter should read 0V, remove the wire and activate (automatic recovery), the voltage of P+P- should still be equal to the voltage of B+B-.
C. Short-circuit more than 10 times in the same way.
Remarks: The battery cell voltage 3.6V-3.8V is half-charge short-circuit protection, and 4.0V-4.2V is full charge short circuit protection.
Short circuit protection test connection diagram
Precautions:
The internal resistance of the short-circuit wire should be ≤20.0mΏ, the wire diameter ≥φ1.00mm
2. Test method for short circuit protection delay
A. Weld a 2512/10mΩ/±1% resistor at P-, and use the probe of the oscilloscope to collect the voltage across the resistor, as shown in Figure 1.
B. Short-circuit P+ P- at this time, and a waveform will be obtained on the oscilloscope, as shown in Figure 2. The short-circuit delay can be obtained from the schematic diagram of the oscilloscope.
3. Test method of overcurrent protection
The BMS protection board is connected to the electronic load. After activation, increase the current of the electronic load until protection. The instantaneous current value before the load current jumps to 0 A is the overcurrent value. During this process, the protection board should have no abnormal phenomena (such as smoke, fire, burnt smell, buzzing, etc.), and the no-load output voltage after the test should still be equal to B+ B-terminal voltage.
Precautions:
Ensure the voltage of the cell, and when the voltage is insufficient, connect the cell in parallel to help charge a constant current source, and adjust the voltage of the constant current source to be consistent with the cell to prevent the over-discharge protection state.
Overcurrent protection current test connection diagram
4. Test method of overcurrent protection delay
Weld a 2512/10mΩ/±1% resistor at P-, use the probe of the oscilloscope to collect the voltage across the resistor and connect an electronic load between P+ and the resistor.
Precautions:
Ensure the voltage of the cell, and when the voltage is insufficient, connect the cell in parallel to help charge a constant current source, and adjust the voltage of the constant current source to be consistent with the cell to prevent the over-discharge protection state.
5. Test method for discharge conduction
Connect the BMS protection board according to the schematic diagram and activate it, set the load current to 1.00A, and then use a millivoltmeter to detect the voltages from P+ to B+ and P- to B-. The sum of the two voltage values is the normal operation of the protection board Turn on the internal resistance.
Schematic diagram of the internal resistance detection method during discharge
6. Overcharge protection voltage detection method one
B. Use the same method as above to detect the overcharge protection voltage of other battery-saving cores.
Precautions:
The voltmeter should be tested to the B+,…, B- pads of the protection board.
7. Test method of overcharge protection delay
Use the same method as above to detect the overcharge voltage protection delay of other battery-saving cores.
8. Test method for overcharge and sleep
Connect the BMS protection board to the analog power supply, battery cell, and voltmeter as shown in the figure below and activate it, add the charger to C+ C- to charge the battery cell through the protection board, adjust the analog power supply to 4.3V, and the charger stops charging. The voltage meter between VCC and B- within 1s shows 0V, and it can be judged as overcharge dormancy.
9. Test method of over-discharge protection voltage
Adjust the open circuit voltage of the programmable power supply to 3.8±0.2V and the short-circuit current to the maximum; then connect it to the protective board with qualified overcharge protection voltage, programmable power supply, voltmeter, and electronic load as shown in Figure 1, and Activate, the constant current source ammeter should display a certain discharge current value; then gradually reduce the voltage of the programmable power supply, when the voltage reading of the multimeter drops to a certain value within the standard over-discharge protection voltage range.
Key points and precautions:
- The voltmeter should be as close as possible to the pads of the protection board B+, BM, and B-.
Each section has requirements for both function and data. Only when the over-discharge protection function and data of all sections are normal, the over-discharge protection voltage of the protection board is qualified.
10. Test method for over-discharge sleep
Connect the protection board to the analog power supply, battery cell, and voltmeter as shown in the figure below, and activate them. Work with load at the output terminal and adjust the analog power supply voltage to 2.4V; the load stops discharging, and the voltmeter is between VCC and B- within 1mm If the display is 0V, it can be judged as over-discharge sleep.
11. Discharge sleep
Pay attention to the voltage of the voltmeter. Within 5 minutes, the voltmeter between VCC and B- shows 0V, and it can be judged as a discharging sleep.
12. Self-consumption test method
Connect the BMS protection board to the battery cell and the microammeter as shown in the figure, and activate it. After the 60s, the reading of the microammeter after it stabilizes is the self-consumption current value of the protection board.
