Safety Test of The Relief  Vent

(Controlled By Pressure)

Cells: 3.2 V 20 Ah & 3.2 V 60 Ah

Purpose:  Test the effectiveness of GMET relief vent.

Design of Relief vent:  Vent would open to discharge pressure when the

                                            Pressure of vapor of electrolyte inside of cell is

                                            in between 0.25~0.6 mPa (87 psi or 6.11 Kg f/cm²)

Input :      5V 300 Amp power

Ambient temperature of the testing location: 32 ℃

6 points on the surface of cell are monitored.

The temperature distribution shows the record of 6 points of the temperature and time on cell.

Temperature Distribution during  Safety Test

    When a short circuit or over charge occurred in the cell, the air pressure inside the cell would rise higher and higher till it breaks the shell or explosion. With a GMET design controlled by pressure relief vent, the vent on battery cell would open when the air pressure inside the cell higher than 0.2~0.6 mPa (87 psi or 6.11 Kg f/cm²).

    From the ideal gas law PV=nRT, to monitor the temperature is a proper parameter to evaluate the effectiveness of pressure controlled relief vent.

  The 6 points of temperature on the surface of cell were monitored, the temperature of battery cell can’t higher than 105 ℃ after the relief vent discharged at the controlled pressure range.

    The temperature inside of cell might higher than what the 6 points measured. However the 105 ℃ peak and down turn of the temperature curve shows the temperature inside cells won’t get higher. It proved the relief vent working and the cell won’t get flame or burning and no risk of explosion. 

    If something occurred on the battery cells, the temperature of GMET cell through designed relief vent working would still less than 105 ℃. Since the temperature of cells won’t higher than 140 ℃, there is no chance for GMET cells to reach thermal runaway temperature. It is the safety of the GMET cell.

Test of  The Advanced Design Relief  Vent

(Controlled By Temperature)

Cells: 3.2 V 20 Ah & 3.2 V 60 Ah

Purpose:  Test the effectiveness of the advanced design GMET relief vent.

Design of Relief vent:  Vent would open to release pressure when the

                                            temperature of vapor of electrolyte is higher than 95 ℃.

Input :      5V 300 Amp power

Ambient temperature of the testing location: 32 ℃

6 points on the surface of cell are monitored.

The temperature distribution shows the record of 6 points of the temperature and time on cell.

Temperature Distribution During Safety Test

Observation of the Temperature Distribution

    When a short circuit or over charge occurred in the cell, the temperature of cell is getting higher and higher till it breaks the shell or explosion. With a GMET advanced design relief vent, from the 6 points temperature curve monitored, the temperature of battery cell after relief vent worked can’t higher than 100 ℃ and it also shows the temperature curve down turn. The temperature inside of cell might higher than what the 6 points measured. However it proved the vent working and the cell won’t get flame or burning and no risk of explosion. 

    If abnormal situation occurred on the cells, the temperature of GMET cells through the working of relief vent would still less than 100 ℃. Since the temperature of cells won’t higher than 140 ℃, there is no chance for GMET cells to reach thermal runaway temperature. This is the safety of the GMET cells.