Composite Graphite Bipolar Plates Under Different Working Conditions

Abstract

Abstract This study uses the molding method to prepare composite graphite bipolar plates to improve the corrosion resistance and electrical conductivity of fuel cell bipolar plates, improve the conversion efficiency and service life, and test their environmental adaptability under different working conditions. In this experiment, the fuel cell test system (850e) is used to test the voltage change curve and power density change curve of the proton exchange membrane fuel cell (PEMFC). Under 200 KPa, the voltage of the fuel cell at a current density of 1000 mA/cm2 is 0.719 V. The power density reaches the maximum at 1540 mA/cm2 current density, which is 911 mW/cm 2. The radii of the three curves from 0.1 A/cm2 to 0.5 A/cm2 decrease with the increase of current density. This indicates that at the beginning, the greater the current density is, the smaller the mass transfer resistance inside the fuel cell is, and the smaller the electron transfer resistance during the electrochemical reaction is. However, when the current density increases to 1 A/cm2, the power density of the fuel cell increases slowly. In the 12-hour constant current density test, it is found that the fuel cell voltage dropped from 0.641 V to 0.611 V, and the rate of decline was 2.5 mV/h, proving that the overall performance of the fuel cell is relatively stable. The graphite bipolar plate prepared by the molding method has good adaptability under different working conditions, and the comprehensive performance is stable under long-term testing.