NOVELTY - A high output voltage planar fuel cell, in which electrolyte membranes (20) cover cell interconnection structures in interspaces (Z) between individual cells.    USE - As a high output voltage fuel cell useful for small electrical equipment such as portable computers.    ADVANTAGE - The fuel cell has a very compact, modular, planar construction and ensures a gas-tight electrical connection between the anode and cathode sides of the individual cells.    DETAILED DESCRIPTION - A high output voltage fuel cell comprises a flat arrangement of at least two individual cells having an electrolyte membrane (20) coated with anode and cathode electrodes (21). The membranes (20) of adjacent cells extend into the interspace (Z) between individual cells where they overlap one another and tightly cover each side of the cell interconnection structure (22) which is impermeable to fuel in its plane within the interspace.    An INDEPENDENT CLAIM is also included for a fuel cell battery comprising a stack of the above planar fuel cells separated by intermediate housing plates, the first and last planar fuel cells being closed by housing end plates.    Preferred Features: The cell housing (24) contacts both membranes (20) under pressure within the interspace (Z), a seal (23) being positioned between the housing and each membrane. The interconnection structure (22) comprises flat foils or perforated and/or expanded sheets, especially of special steel or titanium, or woven fabric, paper or fleece of carbon and/or metal. The electrolyte membrane (20) consists of a cation exchange membrane which is resistant to hydrolysis, oxidation and hydrogen or methanol. An electrically nonconductive foil may be located between the interconnection structure (22) and each membrane (20) within the interspace and the interconnection structure may be coated with an inert material, especially a polymer, within the interspace.    DESCRIPTION OF DRAWING(S) - The drawing shows a fuel cell.    Electrolyte membrane (20)    Electrodes (21)    Interconnection structure (22)    Seals (23)    Housing plates (24, 25)    Interspace (Z)