An electrochemical fuel cell stack comprises a plurality of fuel cell assemblies, wherein, each fuel cell assembly comprises a cell compressed between a pair of flow field plates, a perimeter seal circumscribing the cell and interposed between the pair of flow field plates, and a first diode, having an aspect ratio greater than 10:1, positioned adjacent to, and outside of, the perimeter seal along a first edge of the cell and interposed between the pair of flow field plates.