Modeling of flow-optimal bipolar plates in a PEM fuel cell

The conventional proton exchange membrane (PEM) fuel cells use a graphite bipolar plate with serpentine deign of flow channels to supply hydrogen and air on each side of the plate. The channels are usually narrow and less than 1 mm wide and deep. Due to their small scale, the pressure drop across the channels is significant and fluid in the channels usually surpass the channels by flowing through a porous membrane placed on the channels. This can sometime impact the energy density of the bipolar plates due to non-uniform pressure distribution. An effort is made to design a bipolar plate using flow-optimal channels that ultimately results in uniform pressure distribution and consequently uniform energy density. A conventional serpentine channel design is compared with flow-optimal channels using numerical modeling and the results are compared for pumping power, pressure distribution, and energy density.