A unique clamping mechanism for a cylindrical PEMFC for an enhanced performance

Abstract

Polymer electrolyte membrane fuel cells with planar structures have been proven beneficial; however, cylindrical cells have higher gravimetric and volumetric power density with possible applications in aviation and portable power sources. In this study, a unique clamping mechanism for a cylindrically structured polymer electrolyte membrane fuel cell is developed to improve the performance of the cell through reduced contact resistance over the active area of the cell. The design is structurally modelled and simulated for the contact pressure distribution, followed by experimental validation of contact pressure distribution at the interface of the gas diffusion layer and current collector. The study results in a lower ohmic resistance due to the better electrical contact at the interface of gas diffusion layer and current collector using the new clamping system. The average contact pressure with the new system is observed to be 0.40 MPa, i.e. 33% higher than that of the strap clamping system. In addition, the contact resistance of the cell with new clamps is found to decrease by 18 %, thus resulting in 36 % better performance (55 mW/cm2 at 0.6 V) than that of the conventional clamping system (40 mW/cm2 at 0.6 V). Such enhancement is also attributed to more oxidant supply (12%) at the cathode current collectors due to better cell clamping design.