Abstract: An electrochemical cell comprises a housing defining an interior space, and a separator in the housing dividing said space into an anode compartment and a cathode compartment. A sodium anode is in the anode compartment, a cathode being in the cathode compartment, electrochemically coupled by the separator to the anode. The anode is molten, the separator being a conductor of sodium cations and comprising at least 5 tubes having open and closed ends, the cathode being in the tubes and each tube communicating with a header space in an electronically insulating header. The relationship of the combined area of the tubes available for sodium conduction, and the volume of the interior space, as defined by the quotient: ##EQU1## (in which l is a unit length), has a value of at least 1.0 l.sup.-1.

Abstract: A fuel cell assembly has a current conducting end plate with a conductive body formed integrally with isolating material. The conductive body has a first surface, a second surface opposite the first surface, and an electrical connector. The first surface has an exposed portion for conducting current between a working section of the fuel cell assembly and the electrical connector. The isolating material is positioned on at least a portion of the second surface. The conductive body can have support passage(s) extending therethrough for receiving structural member(s) of the fuel cell assembly. Isolating material can electrically isolate the conductive body from the structural member(s). The conductive body can have service passage(s) extending therethrough for servicing one or more fluids for the fuel cell assembly. Isolating material can chemically isolate the one or more fluids from the conductive body. The isolating material can also electrically isolate the conductive body from the one or more fluids.