Abstract: In a method for regulating a fuel cell stack (1), a current-voltage characteristic of the fuel cell stack is detected and evaluated to determine an operating point of the fuel cell stack, wherein a current-voltage characteristic of the fuel cell stack (1) is detected at time intervals in operation whose gradient has a minimum, a characteristic value (Rmin) for the minimum of the gradient is respectively determined from the detected current-voltage characteristic and a desired value for the operating point is determined by addition of a predefined offset value (Roffset) to the characteristic value, and wherein the fuel cell stack (1) is regulated by the desired value determined in this manner.

Abstract: The method serves for the manufacture of contacts between electrochemically active discs (2) and interconnectors (1) in planar high temperature fuel cells. The interconnectors have air-side and gas-side surface profiles (11, 11?) with contact surfaces (100) located on raised portions (10). A layer consisting of a contacting mixture (22, 22?) is respectively applied onto the electrodes (21, 21?) of the electrochemically active discs or onto the contact surfaces. The surface profiles for the electrodes are brought into contact with the applied layer so that, at a working temperature, the raised portions penetrate into this layer. Connections are formed between the contact surfaces and electrically conductive particles in this way and thus form discrete, homogeneously structured connections between the contact surfaces and the electrodes. Finally the medium embedding the particles is removed under thermal part treatments and the discrete connections are solidified.

Abstract: In a method for regulating a fuel cell stack (1), a current-voltage characteristic of the fuel cell stack is detected and evaluated to determine an operating point of the fuel cell stack, wherein a current-voltage characteristic of the fuel cell stack (1) is detected at time intervals in operation whose gradient has a minimum, a characteristic value (Rmin) for the minimum of the gradient is respectively determined from the detected current-voltage characteristic and a desired value for the operating point is determined by addition of a predefined offset value (Roffset) to the characteristic value, and wherein the fuel cell stack (1) is regulated by the desired value determined in this manner.

Abstract: The method serves for the manufacture of contacts between electrochemically active discs (2) and interconnectors (1) in planar high temperature fuel cells. The interconnectors have air-side and gas-side surface profiles (11, 11?) with contact surfaces (100) located on raised portions (10). The raised portions of each surface profile having the contact surfaces approximately span a plane (12). In this arrangement deviations (?) lie within a predetermined tolerance. In this method a layer consisting of a contacting mixture (22, 22? is respectively applied onto the electrodes (21, 21?) of the electrochemically active discs or onto the contact surfaces. The contacting mixture contains electrically conductive particles and a medium embedding the particles. The surface profiles for the electrodes are brought into contact with the applied layer so that, at a working temperature, the raised portions penetrate into this layer.