Fuel cell structures

Claim 1

In a fuel cell structure constituted by a plurality of cells disposed in electrical contact with one another, each cell comprising: first and second porous electrodes which are plane in shape with parallel faces, one being a cathode and the other an anode, and each include a specific catalyst; an electrolyte filling the gap situated between said electrodes; and two impermeable bipolar current collectors, including at least a central conductive zone having channels on each face of said collectors, a first collector making electrical contact via the high points of its cathode face with the external surface of said cathode, and via its anode face with the external surface of the anode of an adjacent cell, and a second collector making electrical contact via the high points of its anode face with the external surface of said anode, and via its cathode face with the cathode of the other adjacent cell, said collectors having top and bottom parts situated on either side of central conductive zones, orifices provided in said top and bottom parts to allow electrolyte and fuel to flow through the cell structure, the first electrode being pressed against a first frame of insulating plastic material and having a central orifice in the shape of a quadrilateral, said frame including bottom and top portions having orifices for conveying fuel and electrolyte through the cell structure, said frame orifices corresponding to the orifices provided in the collectors, means provided on one face of said frame for conveying electrolyte from one of said electrolyte-conveying orifices acting as an inlet orifice, to an electrolyte compartment situated between the two electrodes, and from said compartment to another electrolyte-conveying orifice acting as an outlet orifice, said means including grooves that open out into hollow portions constituting electrolyte distributing and collecting manifolds disposed on the top and bottom portions of the frame along two opposite sides of the central orifice and in communication with the electrolyte chamber by means of a plurality of parallel microchannels delimited by ribs; the improvement wherein the fuel cell structure further includes a second frame of an insulating plastic material, having the same contour as the first frame against which the first electrode is pressed and having electrolyte and fuel conveying orifices corresponding to those provided in said first frame, said second frame being applied by a plane face on the face of the first frame having the grooves and the distributing and collecting manifolds, and being fixed to said first frame in such a manner as to seal the electrolyte distribution network, the second electrode being pressed against the other face of the second frame, and the electrolyte compartment being defined by the electrodes and the central orifices of the two frames; whereby, upon supply of the fuel and electrolyte to said orifices for conveying fuel and electrolyte within said first and second frames, an oxidizing gas flows between said cathode and the cathode face of the first collector, and a fuel gas flows between said anode and the anode face of the second collector.