Abstract: Flow field plates in solid polymer electrolyte fuel cells can be subject to ice blockages in certain areas during freeze start-up, e.g. the backfeed ports and slots used in some flow field plate designs which connect an outlet plenum channel for a reactant to its outlet. By incorporating a similar and adjacent relief backfeed port, slot and plenum channel arrangement in which the relief plenum channel is separated from the outlet plenum channel by a landing, a relief outlet for the reactant is provided through the adjacent gas diffusion layer.

Abstract: Flow field plates in solid polymer electrolyte fuel cells can be subject to ice blockages in certain areas during freeze start-up, e.g. the backfeed ports and slots used in some flow field plate designs which connect an outlet plenum channel for a reactant to its outlet. By incorporating a similar and adjacent relief backfeed port, slot and plenum channel arrangement in which the relief plenum channel is separated from the outlet plenum channel by a landing, a relief outlet for the reactant is provided through the adjacent gas diffusion layer.

Abstract: A membrane electrode assembly has two gas diffusion layers, two catalyst layers and an ion-exchange membrane interposed therebetween wherein the ion-exchange membrane is cast from a sulphonated polyether ketone/sulfone ionomer. Specifically, the ionomer can be represented as A-B-C wherein Further x, y, z represent the mole ratios of each moiety in the ionomer such that x is between 0.25 and 0.40; y is between 0.01 and 0.26; and z is between 0.40 and 0.67. Melt viscosity of the corresponding base polymer also affects performance in the fuel cell, particularly at values over 0.4 kNsm?2 as measured at 400° C., 1000 s?1. In preparing the membrane electrode assembly, the catalyst layers may be coated directly on the membrane and then bonded with two gas diffusion layers.