NOVELTY - Fabrication of an assembly of basic elements of a fuel cell tier involves using a porous matrix in which are located, for each basic element, an ion conductor surrounded by an anode (22) and a cathode (23). The elements are insulated by a peripheral seal (21) and two insulating walls (25). Electron conductors (26) connect the anode of one element to the cathode of an adjacent element.    USE - Fuel cells.    ADVANTAGE - Fuel cells can be manufactured without having to resort to costly machining or troublesome mechanical installations. Optimal sealing is achieved between the assembly of basic elements and their two-pole plates.    DETAILED DESCRIPTION - The assembly of basic elements of the type anode/membrane/electrode comprises:    a series of anodes (22) on a first side of a plate constituting the assembly and insulated from each other;    a series of cathodes (23) located on the second side of the plate constituting the assembly, insulated from each other and slightly offset with respect to the series of anodes (22);    an ion conductor (24) located between each anode (22)/cathode (23) pair and located within the thickness of the assembly;    an electron conductor (26);    pairs of vertical insulating walls (25) around each electron conductor (26); and    a peripheral seal (21) located around all the elements, across the whole thickness of the plate with a slight extra thickness on each side.    Fabrication of the assembly involves using a support comprising a matrix material in which and on which are deposited the different elements of the assembly.    The sequence of fabrication stages includes:    cutting the matrix material, which is porous and can be made of Teflon or glass, into a desired shape to form the plate,    depositing a sealing layer (21) across the whole thickness and the periphery of the plate and with a slight extra thickness at the sides, and a pair of vertical insulating walls (25) for delimiting the different basic elements;    depositing the ion conductor (24) into the whole thickness of the plate, except between the pair of walls (25),    depositing electron conductors (26) between the pair of walls (25);    depositing anodes (22) on a first surface of the plate, and cathodes on the other surface of the plate; and    depositing an electron collector (27) located at one of the two ends of the series of anodes and the series of cathodes.    DESCRIPTION OF DRAWING(S) - The drawing shows an assembly of basic elements produced according to the invention.    Peripheral seal (21)    Anode (22)    Cathode (23)    Ion conductor (24)    Insulating walls (25)    Electron conductors (26)    Electronic collector (27)