Bipolar plates and regenerative fuel cell stacks including same

A bipolar plate and regenerative fuel cell stacks including the bipolar plates and membrane electrode assemblies (MEAs) alternately stacked. The bipolar plate comprises a plate main body formed of an electrically conductive material. The plate main body has a first surface and a second surface opposite the first surface. Each surface has reaction flow channels through which fluids pass. The reaction flow channels on the first surface have a plurality of ribs therebetween forming an interdigitate flow field pattern. The reaction flow channels on the second surface have a plurality of ribs therebetween forming an interdigitate flow field pattern or a flow field pattern different from an interdigitate flow field pattern, e.g., a serpentine flow field pattern.