NOVELTY - An electrically conductive electrochemical cell component comprises a first coolant plate having a mating region and an adjacent plate having a complementary region. The first coolant plate and the adjacent plate each comprise a polymer and conductive filler. The first coolant plate is joined to the adjacent plate by a seal formed by the polymer at the mating region and the complementary region.    USE - For use in an electrochemical cell of a fuel cell stack (claimed).    ADVANTAGE - The invention provides an electrically conductive electrochemical cell component where a coolant plate is joined to either an adjacent coolant plate or an adjacent bi-polar plate without using any additional gasket or sealant. Since no additional material is used for the seal, there is no problem of material incompatibility during sealing and long-term seal material degradation issues are eliminated. The sealed plates can also tolerate higher operating pressures and temperatures. The seal is made from the same material as the coolant plate or bi-polar plate so there is no contamination expected from the seal and the conductivity of the joined plates is expected to be the same as that of the plates themselves. The electrically conductive electrochemical cell components reduce the number of individual components in the electrochemical cell stack and make the stack assembly process faster and easier.    DETAILED DESCRIPTION - An electrically conductive electrochemical cell component comprises a first coolant plate (21) and an adjacent plate, wherein the adjacent plate is a second coolant plate or a bipolar plate (5). The first coolant plate comprises mating region(s) for mating with a complementary region on the adjacent plate. The first coolant plate and the adjacent plate each comprise a polymer and conductive filler. The first coolant plate is joined to the adjacent plate by a seal formed by the polymer at the mating region and the complementary region.    DESCRIPTION OF DRAWING(S) - The figure shows a coolant plate and bi-polar plate of the invention.    Bipolar plate (5)    Coolant plate (21)    Rib (25)    Groove (30)    Flow field channel (32)