US Patent 7270909 Bipolar plate having offsets

A bipolar plate for a PEM fuel cell is disclosed. The plate includes a plurality of channels, wherein the ends of the channels are staggered. The plate also includes a plurality of tunnels, wherein the ends of the tunnels are staggered. The plate further includes a cathode and an anode, wherein a portion of the cathode overhangs a portion of the anode. These staggered/offset features allow for an increase the capillary meniscus of water droplets passing therethrough, allowing for a reduction in the pressure required to move the water through the cell and out to the header volume of the stack.