Abstract: The invention relates to a fuel cell system comprising a housing including a chamber for accommodating a fuel cell stack. The fuel cell system has various features that can also be independently embodied, namely: a U-shaped air channel including air inlet channels and air outlet channels which include an inlet or outlet on the same side of the housing of the fuel cell system; at least two fans or compressors that are disposed downstream of each other in an air flow direction in the air inlet channel or in the air outlet channel; a housing that has two additional, separate housing sections apart from a chamber for a fuel cell stack and an air inlet channel and an air outlet channel; and an air bypass channel which is arranged between an air inlet channel for introducing ambient air into a chamber for the fuel cell stack and an air outlet channel for discharging air from the chamber for the fuel cell stack.

Abstract: The invention relates to a membrane electrode unit for fuel cells. The inventive membrane electrode unit comprises a reinforcing frame that is situated on the periphery and in the area of openings which are placed in the active portion of the membrane electrode unit and provided for guiding material or for installation. Said reinforcing frame is formed by a hot-melt-type adhesive layer that is applied on both sides and is formed by at least one rigid plate. The hot-melt-type adhesive layers which protrude over the outer edge of the membrane electrode unit enter into an intimate bond, due to the effect of pressure and heat, with the rigid plates and with the membrane electrode unit as well as with one another in the projecting area. The hot-melt-type adhesive comprises ionic or strong polar groups which interact with the ionic groups of the polymer electrolyte membrane and which ensure a high degree of adherence between the hot-melt-type adhesive and the membrane electrode unit.

Abstract: A fuel cell stack including bipolar plates disposed between membrane-electrode units. The stack has two end-position monopolar plates. Two current collectors and two end plates enclose the stack on opposite sides said current collectors have at least one collector passage hole with a port end face. The stack includes at least one connection port and substantially annular sealing elements. The two end plates have at least one end plate passage hole communicating with the at least one connection port and the at least one collector passage hole. The sealing elements each have an opening. A single sealing element completely seals the transporting of media between the end face of a connection port and the end-position media-carrying plate by being disposed in the passage holes in the end plate and the current collector for transporting the reaction and cooling media to and from the opening in the adjoining end-position plate.