A power generator includes a fuel cell having a proton exchange membrane for generating electricity from hydrogen and oxygen. An oxygen generator is coupled to the proton exchange membrane for providing oxygen to the proton exchange membrane. A hydrogen producing fuel may be used to provide hydrogen to the proton exchange membrane.

A liquid electrolyte fuel cell system (10) comprises at least one fuel cell with a liquid electrolyte chamber between opposed electrodes, the electrodes being an anode and a cathode, and means (30, 32) for supplying a gas stream to a gas chamber adjacent to the cathode and withdrawing a spent gas stream (38) from the gas chamber adjacent to the cathode, the system also comprising a liquid electrolyte storage tank (40), and means (42, 44, 47, 48) to circulate liquid electrolyte between the liquid electrolyte storage tank (40) and the fuel cells. In addition the system comprises a water storage tank (60) adjacent to the storage tank (40), and means (50, 51) for condensing water vapor from the spent gas stream (38), and for feeding (56) the condensed water vapor into the water storage tank (60). The water storage tank (60) has an overflow outlet (64); and a communication duct (68) linking the liquid electrolyte storage tank (40) and the water storage tank (60) below the level of the overflow outlet (60). This automatically replaces any water that evaporates from the electrolyte, without requiring any electronics.

A method for drying a fuel cell (10) for generating electrical energy for a consumer (20), in particular for a vehicle (20), in which an anode gas having a first reactant is supplied to an anode (200), and a cathode gas having a second reactant is supplied to a cathode (100), and the reactants are converted into electricity along a flow path (300) in the fuel cell (10) by means of an electrochemical reaction, the method having the following steps: a) flushing (2) the cathode (100) with the cathode gas; b) operating (4) the fuel cell (10) with so little cathode gas that the second reactant is substantially consumed along the flow path (300) by the electrochemical reaction for conversion to electricity, an electric current density of the fuel cell (10) being less than 20% of a maximum achievable electric current density of the fuel cell (10).

A fuel cell system includes: a wetness target value calculating unit configured to calculate a target value of a wet state of the fuel cell; a gas required flow rate calculating unit configured to calculate a cathode gas required flow rate on the basis of a power generation request to the fuel cell; a wetness-control anode gas flow rate calculating unit configured to calculate a wetness-control anode gas circulation flow rate at least on the basis of the wetness target value and the cathode gas required flow rate during a dry control; an anode gas flow rate control unit configured to control an anode gas circulation flow rate on the basis of the wetness-control anode gas circulation flow rate; a wetness-control cathode gas flow rate calculating unit configured to calculate a wetness-control cathode gas flow rate at least on the basis of the wetness target value and a measured value or estimated value of the anode gas circulation flow rate during the dry control; and a cathode gas flow rate control unit configured to control a cathode gas flow rate on the basis of the cathode gas required flow rate and the wetness-control cathode gas flow rate.

A fuel cell system includes a fuel cell for generating electrical power upon being supplied with anode gas and cathode gas. The fuel cell system includes a wetness control state determination unit that determines whether or not a wetness control of controlling a degree of wetness of an electrolyte membrane of the fuel cell is normally executed, a combined capacitance calculation unit that calculates a combined capacitance of the fuel cell, and an anode gas concentration control unit that determines the occurrence of decrease in an anode gas concentration in the fuel cell or executes a control for increasing the anode gas concentration if the combined capacitance of the fuel cell is smaller than a predetermined value when the wetness control is determined to be normally executed.