NOVELTY - Manufacturing a corrugated fuel cell unit comprises providing a continuous sheet of a composite laminate comprising an ion conductive membrane; and folding the sheet along the first dimension to form a corrugated structure comprising alternating ridges and troughs parallel with each other and with the second dimension.    USE - The method is used for manufacturing a corrugated fuel cell unit. The fuel cell unit is used in a fuel cell, a portable electronic device, and a vehicle (all claimed).    ADVANTAGE - The present invention provides corrugated fuel cell units for use in fuel cells provided with a high volumetric power density capability.    DETAILED DESCRIPTION - Manufacturing a corrugated fuel cell unit comprises providing a continuous sheet of a composite laminate comprising an ion conductive membrane having first and second surface; a first electrocatalyst layer in contact with the first surface of the membrane; a second electrocatalyst layer in contact with the second surface of the membrane; a first metallic mesh in contact with the first electrocatalyst layer and a second metallic mesh in contact with the second electrocatalyst layer, the composite laminate having a first dimension and a second orthogonal dimension; and folding the sheet along the first dimension to form a corrugated structure comprising alternating ridges and troughs parallel with each other and with the second dimension. INDEPENDENT CLAIMS are:    (1) a corrugated fuel cell unit the unit comprising a continuous sheet of a composite laminate comprising an ion conductive membrane having first and second surface; a first electrocatalyst layer in contact with the first surface of the membrane; a second electrocatalyst layer in contact with the second surface of the membrane; a first metallic mesh in contact with the first electrocatalyst layer and a second metallic mesh in contact with the second electrocatalyst layer, the composite laminate folded to form a corrugated structure comprising alternating parallel ridges and troughs;    (2) a fuel cell comprising a corrugated fuel cell unit;    (3) a portable electronic device comprising the fuel cell unit;    (4) a vehicle comprising the fuel cell unit or the fuel cell; and    (5) a composite laminate comprising an ion conductive membrane having first and second surface; a first electrocatalyst layer in contact with the first surface of the membrane; a second electrocatalyst layer in contact with the second surface of the membrane; a first metallic mesh in contact with the first electrocatalyst layer and a second metallic mesh in contact with the second electrocatalyst layer characterized in that the size of the open area and/or the wire diameter of the first metallic mesh is larger than the size of the open area and/or the wire diameter of the second metallic mesh.