NOVELTY - The fuel cell cassette useful in electrochemical, fuel cell and ion exchange applications, comprises an electrochemical cell having a membrane electrode assembly, a reductant flow field, an oxidant flow field and a separator plate, a reductant external manifold, an oxidant external manifold, and a coolant flow field. Each flow field comprises an opening extending through the periphery of the cell and each external manifold comprises a primary manifold and a port in fluid contact with the peripheral openings in the flow field.    USE - Useful in proton exchange membrane fuel cells, electrochemical and ion exchange applications.    ADVANTAGE - The cassettes are capable of producing a sufficient power supply for a variety of applications.    DETAILED DESCRIPTION - The fuel cell cassette useful in electrochemical, fuel cell and ion exchange applications, comprises an electrochemical cell having a membrane electrode assembly, a reductant flow field, an oxidant flow field and a separator plate, a reductant external manifold, an oxidant external manifold, and a coolant flow field. Each flow field comprises an opening extending through the periphery of the cell and each external manifold comprises a primary manifold and a port in fluid contact with the peripheral openings in the flow field to which the external manifold is intended to deliver material. The membrane electrode assembly, oxidant flow field, reductant flow field and separator plate are assembled and encapsulated about the periphery by a sealant. Each external manifold is a volume substantially bounded by the sealant, and an additional elements having a membrane electrode assembly, porous membrane, nonporous membrane, oxidant flow field, reductant flow field, second sealant layer or separator plate in which the volume is in contact with the peripheral openings in the flow field. The reductant external manifold and the oxidant external manifold comprises a volume substantially bounded by the sealant, optionally an additional fluid impermeable material homogenous composition, and a single component comprising a primary manifold conduit and a port for mating with peripheral openings of an equal number of flow fields to which the manifold is intended to deliver material. The volume is defined by a removable mold element, which is fluidly connected with the peripheral openings of the flow fields to which the manifold is intended to deliver or remove material. The removable mold element is removed after encapsulation of the periphery of the cassette with the sealant. The separator plate and flow fields are integrated into a graphite plate. Each flow field peripheral opening extends through a portion of a thickness of the graphite plate without extending through a surface of the plate, and provides fluid contact between the external manifold and the flow field to which the manifold is intended to deliver the material. The flow field peripheral opening comprises an adapter for forming a fluid tight seal with the removable molding element, which is placed in contact with the flow field peripheral openings. The adapter comprises a flat surface for mating to a removable mold element having a planar surface, a curved surface for mating to a removable mold element of cylindrical, elliptical or similar shape, and a concave volume for forming a fluid tight seal with a protrusion of the removable mold element. The removable mold element comprises a main body and protrusions. The flow field peripheral opening forms a fluid tight seal to a molding element, which is useful to form the external manifold. The molding element is a solid body comprising a plenum and a runner. The plenum defines the volume of the manifold and the runners, which forms the fluid tight seal with each flow field peripheral openings such that the manifold is fluidly connected to the flow field after removal of the molding element. The coolant flow field comprises two opening extending through the periphery of the flow field, and two coolant external manifolds comprising a primary manifold and a port capable of coupling to the peripheral openings in the coolant flow field. The graphite plate has zero or one- oxidant flow field, reductant flow field, and coolant flow field. The membrane electrode assembly is in contact with the reductant flow field and the oxidant flow field. The sealant contemporaneously seals a junction between the removable molding element and the peripheral openings of the flow fields to which the manifold is intended to deliver a material during the encapsulation process. A void is formed by removal of the molding element, which forms the volume of the external manifolds fluidly connected to the flow fields to which the manifold is intended to deliver the material. A composite membrane electrode assembly and separator plate comprises no grooves, holes or other aperture extending through the entire thickness of the assembly and plate. The coolant external manifold opening comprises the single component having the primary manifold conduit and the port for mating to peripheral openings of an equal number of coolant flow fields. The external manifold comprises two primary manifolds and two sets of ports, which are not fluidly connected such that each primary manifold and each set of ports can deliver or remove material to flow fields to which each primary manifold is intended to deliver or remove material. The graphite plate is machined or molded out of carbon/polymer composite, graphite or metal in which the plate is stamped from a metal sheet. The sealant is introduced by- pressure assisted resin transfer under a positive pressure of 0-250 psi, vacuum assisted resin transfer under a partial pressure of 750-1m Torr or injection molding. The sealant or resin is introduced under a pressure differential of +15 to -15 psi. INDEPENDENT CLAIMS are included for:    (1) a method of manufacturing electrochemical cassette; and    (2) a fuel cell stack.    DESCRIPTION OF DRAWING(S) - The diagram shows a stack with several plenum inserts:    Rod insert; (1)    Elastomer tube insert; (2)    Top port; (3)    Top endplate; (4)    Bipolar plate. (5)