Abstract: The humidifying device for a fuel cell has a membrane, one side of which is exposed to cathode exhaust gas of a fuel cell for extracting water vapor from the exhaust gas. A connecting element connects the other side of the membrane to an anode or cathode gas supply to the fuel cell. In operation, water vapor permeates through the membrane and passes on through the connecting elements to humidify the gas being supplied to the fuel cell. A vacuum pump may additionally be provided to enhance the extraction of water vapor from the exhaust gas. A no metering unit allows accurate metering of the humidity of the cathode or anode gas supply.

Abstract: A fuel tank, in particular for fuel-cell systems, which can feed fuel into a system via a mechanism without a pump or the like. This is achieved by a fuel tank with a fuel cavity of variable size and a mechanism for compressing the fuel cavity. The fuel cavity is preferably bounded by a cylindrical inner wall of the fuel tank, by a circular end surface of the fuel tank and by a circular, displaceable intermediate wall. The intermediate wall is forced essentially in the direction of the fuel cavity by a spring and has a form fit with the cylindrical inner wall. A feed device and a discharge device allow incorporation in a fuel line. The system also includes a control device and a method for this fuel container, which is thus enabled to have the following operating states: A. fuel-cell system is switched on: discharge valve open, feed valve closed; B. fuel-cell system is in operation: discharge valve open, feed valve open; C. fuel-cell system is switched off: discharge valve closed, feed valve open; and D.

Abstract: A fuel cell system which has a fuel cell is described. Also provided is a device for producing/preparing the fuel, for example hydrogen, which is connected on its outlet side to a fuel supply line and on its inlet side to a device for supplying fuel. The device for supplying fuel has a dual pump, in which a starting material for the fuel, stored in the motor-fuel tank, and water fed in via a water supply line, which is for example process water produced during the fuel cell process, are mixed to form a fuel/water mixture. This fuel/water mixture is intermediately stored in an intermediate tank before it is fed to the device for producing/preparing the fuel.

Abstract: A fuel cell system which has a fuel cell with a supply line and a discharge line for a fuel as well as a supply line and a discharge line for an oxidizing agent. Also provided is a fuel tank which contains, for example, benzene or methanol for producing the fuel for the fuel cell. To avoid the release of hydrocarbons from the fuel contained in the tank, a filter element, for example an active carbon filter, is connected to the fuel tank. To be able to regenerate the filter element, the filter element is connected to the discharge line for the oxidizing agent and/or the discharge line for the fuel. The filter element is regenerated by the flow of exhaust gas from the fuel cell. The filter element is preferably connected via a connecting line to a burner, with the result that the hydrocarbons taken up by the flow of exhaust gas can be burned in the burner. Furthermore, by designing the fuel cell system appropriately, a leakage diagnosis can also be performed in the fuel tank.