Insert-molded, externally manifolded, sealed membrane based electrochemical cell stacks

A fuel cell stack comprising:

• a) at least one fuel cell including:
• i) a membrane electrode assembly;
• ii) a reductant flow field disposed proximate a first side of the membrane electrode assembly, the reductant flow field including a reductant flow channel extending to a periphery of the fuel cell;
• iii) an oxidant flow field disposed proximate a first side of the membrane electrode assembly, the oxidant flow field including an oxidant flow channel extending to the periphery of the fuel cell;
• b) a unitary plenum housing formed about the periphery of the fuel cell, the unitary plenum housing at least partially defining:
• i) a reductant manifold in fluid communication with the reductant flow channel, the reductant manifold and the reductant flow channel cooperating to form a reductant plenum;
• and
• ii) an oxidant manifold in fluid communication with the oxidant flow channel, the oxidant manifold and the oxidant flow channel cooperating to form an oxidant plenum, wherein at least one of the reductant and oxidant manifolds includes a portion of sealant having a negative impression of a manifold insert defining a volume at least partially bounded by the sealant.