Gas Crossover in Polymer Electrolyte Membranes

The polymer electrolyte membrane fuel cell system has received a considerable attention as one of powerful candidates for the next generation power sources. Numerous studies have been carried out to develop good performance and high durability systems with PEM fuel cells. As a result, several solutions to enhance the operating characteristics have been formed; however, durability of the system is still required to be improved.

As the durability of the system emerges as one of the critical problem, understanding the degradation mechanism in the fuel cell system is the key step for a better system design. Gas crossover has a great influence on the degradation of the membrane electrode assembly. Thus, it is essential to investigate the crossover of related gases through the membrane gas crossover has a negative effect not only on the performance but also on the durability of the system.

In this study, the novel detecting technique to measure accurate gas crossover rate and the effect of various parameters on gas crossover with different gases are investigated experimentally. Experiments are performed with the unit cell which has active area of 25 cm² with four flow channels. To distinguish the effect of the specific parameter, it is controlled separately in the experimental setup. For measuring the gas crossover rate, mass spectrometer is used in this experiment. Consequently, the effects of temperature, relative humidity condition, hydrogen pressure, and membrane thickness on gas crossover rate in PEM fuel cells are investigated.