NOVELTY - A fuel cell assembly has separate elements, groove network(s) extending through assembly and a seal provided within groove network which is formed in-place after assembly of separate elements. The seal provides barrier between separate elements to define chamber for fluid used for operating fuel cell. The groove network has filling port(s).    USE - For generating power.    ADVANTAGE - Each fuel cell are efficiently and accurately clamped in position of membrane active area in fuel cell assembly. Since anode and cathode flow field plates provided in fuel cell assembly are thin, overall dimensions of fuel cell assembly are reduced. The sealing technique adapted in fuel cell assembly provides thin bottom wall to groove network. The curable seal material forms an elastomeric material which chemically bonds components of fuel cell assembly and thus seal performance is enhanced. Also the overall durability of the fuel cell is increased. The fuel cell is constructed economically; since the seal is formed in place after assembly of individual elements, labor intensive cost and complexity of manually assembling gaskets in the groove network are eliminated. Complex tools are not required for assembling gaskets, and wastage of gasket material when cutting gaskets from sheet material is eliminated. The individual components of assembly are manufactured easily with simple design. The sealing material seals fuel cell assembly and electrically insulates fuel cell assembly. The seal material fills imperfections and variations in tolerances on the various components of fuel cell assembly.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) formation of seal in fuel cell assembly which involves assembling the separate elements of fuel cell together. A groove network is provided and then a filling port is provided in groove network. A source of uncured liquid seal material is supplied to filling port and seal material is injected into groove network to fill groove network and gas is simultaneously removed from groove network. The seal material is cured to form seal in groove network;    (2) an electrochemical cell assembly; and    (3) formation of seal in electrochemical cell assembly.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic sectional view of the fuel cell assembly.