FUEL CELL FLOW CHANNELS AND FLOW FIELDS

A fuel cell anode flow field comprises at least one flow channel with a cross- sectional area that varies along at least a portion of its length. In some embodiments, the channel width decreases along at least a portion of the channel length according to a natural exponential function. This type of anode flow field may improve performance, reduce fuel consumption and/or reduce detrimental effects such as carbon corrosion and catalyst degradation, thereby improving fuel cell longevity and durability. When operating the fuel cell on either a substantially pure or a dilute fuel stream, this type of anode flow field may provide more uniform current density, which is desirable for efficient fuel cell operation and improved fuel cell performance and lifetime. Variants of the non-conventional reactant flow channels are described, along with examples of incorporating such flow channels into reactant flow field plates, fuel cells and fuel cell stacks.