NOVELTY - A fuel cell (10) to produce electrical energy comprises a proton exchange membrane electrolyte (12); two reactant inlets (18, 24); a sealed coolant plate (30); and an antifreeze saturator (42) with a high molecular weight direct antifreeze solution (44). The antifreeze solution includes an antifreeze component selected from ethylene oxide chains terminated by functional alkyl or hydroxyl groups, linear alcohols, branched alcohols, polyethylene glycols, methoxypolyethylene glycols and/or dimethoxy-polyethylene glycols; each having molecular weight of 200-8000 AMU.    USE - For producing electrical energy (claimed) useful in transportation vehicles, portable power plants, and as stationary power plants; and to power electrical apparatus such as generators and transportation vehicles.    ADVANTAGE - The fuel cell having sealed cooler plate eliminates any need for thawing a reactant inlet saturator; and does not require complicated thawing apparatus for the reactant inlet saturator, and does not require a fuel cell heating mode as part of a complicated start up procedure. The saturator does not require thawing apparatus to melt liquid in the saturator during cold weather start up of the fuel cell. The fuel cell provides corresponding mole fraction that determines thermo-physical properties of antifreeze solutions is only 4.4 mole % for the polyethylene glycol (PEG), but 14.5 mole % for the glycerol for the same -20degreesC freezing point of the high molecular weight direct antifreeze solution. Therefore, the PEG has very little effect on the vapor pressure of water within the solution. Such a high molecular weight direct antifreeze solution thus provides for achieving 90% relative humidity within reactant streams passing through and over the solution, even at fuel cell operating temperatures as high as 80degreesC. Use of an appropriate amount of PEG 400 can produce a high molecular direct weight antifreeze solution having a freezing temperature as low as -40degreesC. The PEG has a near zero or virtually negligible vapor pressure through possible operating temperatures of a fuel cell of -40-100degreesC. Consequently, molecules of the antifreeze component of the high molecular weight direct antifreeze solution do not escape the liquid antifreeze solution into the gaseous fuel and/or oxidant reactant streams passing through and over the solution, thereby leaving the reactant streams humidified with virtually pure water.    DETAILED DESCRIPTION - A fuel cell (10) for producing electrical energy from a first reactant stream and a second reactant stream, comprises: a proton exchange membrane electrolyte (12) secured between a first catalyst (14) and a second catalyst (16); a first reactant inlet (18); a second reactant inlet (24); a sealed coolant plate (30) secured in heat exchange relationship with the catalysts; and an antifreeze saturator (42) secured in fluid communication with one of the first or the second inlets. The saturator contains a high molecular weight direct antifreeze solution (44) and directs a reactant stream to pass from the first or second reactant inlet in fluid communication with the direct antifreeze solution and back into the first or second reactant inlet. The antifreeze solution includes an antifreeze component selected from ethylene oxide chains terminated by functional alkyl or hydroxyl groups, linear alcohols, branched alcohols, polyethylene glycols, methoxypolyethylene glycols and/or dimethoxy-polyethylene glycols; each having a molecular weight of 200-8000 AMU (preferably polyethylene glycol having a molecular weight of 200-8000, preferably 400 AMU). The first inlet is secured in fluid communication with the first catalyst for directing the first reactant stream to flow adjacent the first catalyst. The second reactant inlet is secured in fluid communication with the second catalyst for directing the second reactant stream to flow adjacent the second catalyst. The sealed coolant plate is secured in heat exchange relationship with the catalysts. The plate directs a coolant stream to pass through the plate. The fuel cell further comprises a saturator re-supply line including an antifreeze re-supply line (48), and a second antifreeze saturator (46). An INDEPENDENT CLAIM is included for humidifying a reactant stream of the fuel cell passing first and/or second reactant streams from the first and/or second reactant inlets in direct contact with a high molecular weight direct antifreeze solution within antifreeze saturator; and directing the reactant streams from the antifreeze saturator through flow field adjacent first or a second flow field.    DESCRIPTION OF DRAWING(S) - The figure shows a simplified schematic view of the fuel cell.    fuel cell (10)    proton exchange membrane electrolyte (12)    first catalyst (14)    second catalyst (16)    first reactant inlet (18)    second reactant inlet (24)    sealed coolant plate (30)    antifreeze saturator (42)    antifreeze solution. (44)