NOVELTY - A fuel cell assembly (100) comprises separate elements, groove network(s) extending through the fuel cell assembly and including filling port(s) for groove network(s), seal in each groove network that has been formed in place after assembly of the separate elements, and release agent for providing easier disassembly of separate element(s) of fuel cell.    USE - For use as a fuel cell assembly, e.g. electrochemical cell assembly (claimed).    ADVANTAGE - The assembly prevents leakage of gases and liquid required for operation of the individual cells. It provides a more economic construction.    DETAILED DESCRIPTION - Fuel cell assembly comprises separate elements, groove network(s) extending through the fuel cell assembly and including filling port(s) for groove network(s), seal in each groove network that has been formed in place after assembly of the separate elements, and release agent for providing easier disassembly of separate element(s) of fuel cell. The seal provides a barrier between at least2 of the separate elements to define a chamber for a fluid for operation of the fuel cell.    INDEPENDENT CLAIMS are also included for:    (a) a method of forming a seal in a fuel assembly comprising assembling the separate elements of the fuel cell assembly together, providing a groove network extending through the separate elements and filling port open to the exterior in communication with the groove network, providing a release agent for easier disassembly of separate element(s) of the fuel cell, connecting a source of uncured liquid seal material to the filling port and injecting the seal material into the groove network to fill the groove network and simultaneously venting gas from the groove network, and curing the seal material to form a seal in the groove network; and    (b) a composition for forming seals in a fuel cell assembly comprising (pbw) polydiorganosiloxane (100) containing at least2 silicon-atom-bonded alkenyl groups in each molecule, reinforcing filler (5-50), oxide or hydroxide (1-20) of an alkaline earth metal with an atomic weight of at least40, organohydrogensiloxane containing at least3 silicon-atom-bonded hydrogen atoms in each molecule, platinum-type metal catalyst in amount providing 0.1-500 pbw of platinum-type metal/1 pbw of polydiorganosiloxane, and release agent    It is provided that the hydrogen atoms are present in amount providing a molar ratio of silicon-atom-bonded hydrogen atoms in organohydrogensiloxane to silicon-atom-bonded alkenyl groups in polydiorganosiloxane that is 0.4:1-5:1.    DESCRIPTION OF DRAWING(S) - The figure shows an isometric view of a fuel cell stack.    Fuel cell assembly (100)    Anode endplate (102)    Cathode endplate (104)    Air connection ports (106, 107)    Coolant connection ports (108, 109)    Hydrogen connection ports (110, 111)