Endplate effect in an open-cathode proton exchange membrane fuel cell stack: Phenomenon and resolution

Abstract

Proton exchange membrane fuel cells (PEMFCs) have garnered substantial attention as highly promising devices for energy conversion. The operational lifespan and overall output performance of such stacks are inherently governed by the performance of the weakest fuel cell, a phenomenon often referred to as the “Bucket Effect.” Evidently, cells located proximate to the hydrogen inlet endplate exhibit poor performance in comparison to the remaining cells in a 95 cells open-cathode fuel cell stack. In response to this challenge, an innovative approach involving endplate heating has been proposed to mitigate the observed endplate effects. Experimental validation of this approach has been conducted, yielding pertinent results. Furthermore, the internal temperature distribution across the stack exhibits an asymmetric parabolic profile, largely attributed to the intricate interplay of the endplate effects. Comparative analysis against a counterpart stack without endplate heating indicates that an application of 80 W heating power leads to a prolongation of operational duration by 156 s, while 100 W heating extends the operational period by 333 s. 80 W heating increased stack power by 31.5 W while improving output power efficiency by 1.9%, and 100 W heating increased stack power by 45.6 W while improving output power efficiency by 2.74%.