NOVELTY - A fuel cell cooling device comprises a cooling loop, and ion extraction medium (9). The cooling loop circulates a coolant fluid. The ion extraction medium is in a liquid state and is provided at least during an operation of the fuel cell.    USE - Apparatus for cooling fuel cell.    ADVANTAGE - The apparatus uses ion extraction medium that is in liquid state, thus removing dissolved ions from the cooling medium, particularly a coolant fluid. The apparatus eliminates the need for changing cleaning agent.    DETAILED DESCRIPTION - The ion extraction medium is an ionic liquid. The cooling device includes mixing unit provided for mixing the coolant fluid with the ion extraction medium, and dispersal units for a medium. The medium comprises cooling medium, and/or ion extraction medium. The dispersal units include an injection device, a spray device, or an injection and spray device for mixing the ion extraction medium with the coolant fluid. The device includes turbulence generating unit, separating unit for separating the ion extraction medium from the coolant fluid, preparation unit (18) for the ion extraction medium, second cooling loop for the ion extraction medium, units for precipitating foreign ions out of the ion extraction medium by electrochemical precipitation, and units for furnishing the cleaned ion extraction medium to the cooling loop again for an ion extraction. The method includes using an ionic liquid as the ion extraction medium that extracts ions, and performing the ion extraction continuously. An INDEPENDENT CLAIM is included for operating a fuel cell cooling device comprising circulating a coolant fluid in a coolant loop; and performing an ion extraction from the coolant fluid at least during an operation of the fuel cell by an ion extraction medium which is in a liquid state.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the preparation unit for deionizing agent.    Ion extraction medium (9)    Wash cell (10)    Outlets (16, 17)    Preparation unit (18)    Nozzles (32)    Line (34)