Study on low temperature and durability characteristics of gasket for polymer electrolyte membrane fuel cell (PEMFC) depending on cross-sectional geometry

This study investigates the low-temperature and durability characteristics of fuel cell gaskets based on their cross-sectional geometry. Samples of rectangular, half-circular, and mountain shapes produced by injection molding are introduced. Experiments are conducted at -40 degrees C, near the glass transition temperature of EPDM (Ethylene-propylene-diene monomer), to elucidate the differences in airtightness. The maximum pressures capable of maintaining airtightness at -40 degrees C are 1.5, 2.1, and 2.6 barg initially for the rectangular, half-circular, and mountain shapes, respectively. After degradation for 28 days at 120 degrees C, these pressures drop by 0.4, 0.6, and 1.1 barg. Simulations suggest that enhancing sealing performance relies on increasing contact pressure via a smaller contact area but it causes rapid degradation due to the internal stress concentration. Hence, achieving an optimal design balancing airtightness and durability under high pressure is crucial. In this study, it is concluded that the half-circular shape demonstrates the most stable structural performance in this regard.