Interfacial contact resistance in fuel cells is one of the primary challenges that needs to be overcome in the commercialization of fuel cells. This paper summarizes the governing parameters of the resistance such as surface morphology, contact pressure at the interface, electrical conductivities and corrosion resistance of gas diffusion layer and bipolar plate. Also, researchers’ contributions in modifying the cell components and clamping techniques are discussed in detail. Gas diffusion layer is found to be a crucial factor to control the contact resistance and hence its modification techniques are discussed. Moreover, surface of bipolar plate is prone to oxidation in acidic environment of the fuel cell. Different materials, anticorrosive coatings as well as surface modification techniques for the bipolar plate are therefore discussed in detail. Effect of clamping pressure on distribution of contact pressure is highlighted and various clamping techniques suggested by researchers are summarized. Effect of gasket selection on contact pressure distribution is considerable and therefore included in the paper. The review would be helpful for researchers in understanding the importance, reasons of existence and factors influencing the contact resistance at the interface of gas diffusion layer and bipolar plate.

Interfacial contact resistance in polymer electrolyte membrane fuel cells: Recent developments and challenges

Development of cylindrical PEM fuel cells with semi-cylindrical cathode current collectors

Cylindrical polymer electrolyte membrane fuel cells are promising energy conversion devices for next generation transportation applications because of their high volumetric and gravimetric power de...

Effect of gas pressure and clamping pressure on interfacial contact resistance of a cylindrical polymer electrolyte membrane fuel cell

Air-breathing fuel cells, due to their ability of using oxygen directly from air, have the potential to emerge as a primary power source for various applications. Cylindrical fuel cells offer the advantage of higher gravimetric and volumetric power densities compared to conventional planar fuel cells. In the present study, the durability of single cylindrical cell is tested based on a new European driving cycle and the cell is shown to be stable for more than 200 h of operation at different current densities. The decrease in the performance is observed to be the result of increase in membrane resistance rather than catalyst degradation or hydrogen crossover. Furthermore, the performance of a stack of 16 cylindrical fuel cells is evaluated at different relative humidities and temperatures of air on the cathode side. The effect of cell positioning on the stack performance in terms of deficiency of oxygen is also studied. Both relative humidity and temperature are observed to have an effect on the durability of the stack. Increment in the temperature of air is also seen to upset the performance of the stack. Higher relative humidity (⁓80%) and lower temperature (⁓35 C) are observed to stabilize the stack in terms of performance and durability on a time scale of more than 2 h. Keywords— Fuel cells, Air-breathing, cylindrical, temperature, humidity, durability

Performance Evaluation of a Cylindrical PEM Fuel Cell and the Stack

Cylindrical PEM fuel cells have higher volumetric and gravimetric power density compared to planar PEM fuel cells because of the absence of graphite bipolar plates. The performance of the cylindrical fuel cell is largely influenced by MEA compression. In this study, we have developed a cylindrical fuel cell with hollow semi-cylinders acting as the cathode current collector. This design allows for increasing MEA compression without increasing cathode current collector thickness. The decrease in hydrogen flow rate and an increase in hydrogen humidification temperature further increased the cylindrical cell performance. The lower limiting current density obtained at lower hydrogen flow rates can be increased by operating the cell in dead-ended mode. The better performing baffle design for anode current collector in terms of efficient hydrogen utilization is determined from CFD simulations.

Samuel Pearn-Rowe

Papers

Strategies for Effective Utilization of Hydrogen in Cylindrical PEM Fuel Cells