(DE19821985-A1)   NOVELTY - The polymer layer (1) or second layers (3) are corrugated, folded or embossed to form the gas channels (4). Note: both the electrode (2, e.g. carbon fiber) and the second sheet (3, metal sheet) are conductive and connected.    USE - A fuel cell, e.g. for mobile applications, with high power to weight and volume ratio.    ADVANTAGE - The design achieves greater technical simplicity and more economical construction than prior art. Structuring of layers increases active area available. Per unit of volume, power density is increased. Power to weight ratio is also increased. These are key advantages for mobile use. The structure also improves functional reliability over earlier types. Excellent exchange of mass and heat is achieved by the channels formed. Downward gas flow assists clearance of water produced in appropriate channels. Adjacent channels are well sealed from each other, due to the compressible layers. Further physical and electrical specifications appear in the disclosure text. Commercially-available materials and practical examples are discussed. Voltage/current graphs are provided in terms of fleece material selections.    (EP1088360-A1)   NOVELTY - The polymer layer (1) or second layers (3) are corrugated, folded or embossed to form the gas channels (4). Note: both the electrode (2, e.g. carbon fiber) and the second sheet (3, metal sheet) are conductive and connected.    USE - A fuel cell, e.g. for mobile applications, with high power to weight and volume ratio.    ADVANTAGE - The design achieves greater technical simplicity and more economical construction than prior art. Structuring of layers increases active area available. Per unit of volume, power density is increased. Power to weight ratio is also increased. These are key advantages for mobile use. The structure also improves functional reliability over earlier types. Excellent exchange of mass and heat is achieved by the channels formed. Downward gas flow assists clearance of water produced in appropriate channels. Adjacent channels are well sealed from each other, due to the compressible layers. Further physical and electrical specifications appear in the disclosure text. Commercially-available materials and practical examples are discussed. Voltage/current graphs are provided in terms of fleece material selections.