Abstract: Novel methods and apparatus for identifying one or more degraded cells in a fuel cell stack wherein one or more, but not the entirety of, the fuel cells in the stack are turned off while maintaining constant current in the external load and the resulting stack potential is measured.

Abstract: A fuel cell arrangement for carrying out a method for ascertaining the overvoltage of a working electrode in a fuel cell, in which the potential of a reference electrode compared to the grounded counter electrode is measured. For the measurement, a fuel cell comprising a polymer electrolyte membrane is used, in which the counter electrode comprises a lateral edge having at least one convexly curved region, and the electrolyte membrane surface, adjoining the counter electrode, comprises an electrode-free region in which the reference electrode is disposed on the electrolyte membrane surface. In contrast, the working electrode is continuous, which is to say has a large surface.

Abstract: A fuel cell arrangement for carrying out a method for ascertaining the overvoltage of a working electrode in a fuel cell, in which the potential of a reference electrode compared to the grounded counter electrode is measured. For the measurement, a fuel cell comprising a polymer electrolyte membrane is used, in which the counter electrode comprises a lateral edge having at least one convexly curved region, and the electrolyte membrane surface, adjoining the counter electrode, comprises an electrode-free region in which the reference electrode is disposed on the electrolyte membrane surface. In contrast, the working electrode is continuous, which is to say has a large surface.

Abstract: The invention relates to a method for ascertaining the overvoltage of a working electrode in a fuel cell, in which the potential of a reference electrode compared to the grounded counter electrode is measured. For the measurement, a fuel cell comprising a polymer electrolyte membrane is used, in which the counter electrode comprises a lateral edge having at least one convexly curved region, and the electrolyte membrane surface, adjoining the counter electrode, comprises an electrode-free region in which the reference electrode is disposed on the electrolyte membrane surface. In contrast, the working electrode is continuous, which is to say has a large surface.

Abstract: The invention relates to a method for ascertaining the overvoltage of a working electrode in a fuel cell, in which the potential of a reference electrode compared to the grounded counter electrode is measured. For the measurement, a fuel cell comprising a polymer electrolyte membrane is used, in which the counter electrode comprises a lateral edge having at least one convexly curved region, and the electrolyte membrane surface, adjoining the counter electrode, comprises an electrode-free region in which the reference electrode is disposed on the electrolyte membrane surface. In contrast, the working electrode is continuous, which is to say has a large surface.

Abstract: A method for characterizing the catalyst structure in a fuel cell, and in particular the transmission X-ray absorption measurements (XAS), in which a novel fuel cell design is used. The fuel cell comprises a first (planar) electrode having a first catalyst, a second (planar) electrode having a second catalyst, and an electrolyte membrane disposed between the electrodes and having a layer thickness lm, wherein the first electrode comprises at least one catalyst-free circular region having a radius R1max. Contrary to what has been customary until now, the second electrode of the fuel cell according to the invention likewise comprises a catalyst-free circular region having a radius R2<R1max. Advantageously, 0.5 lm?[R1max?R2]?2 lm applies.

Abstract: A method for characterizing the catalyst structure in a fuel cell, and in particular the transmission X-ray absorption measurements (XAS), in which a novel fuel cell design is used. The fuel cell comprises a first (planar) electrode having a first catalyst, a second (planar) electrode having a second catalyst, and an electrolyte membrane disposed between the electrodes and having a layer thickness lm, wherein the first electrode comprises at least one catalyst-free circular region having a radius R1max. Contrary to what has been customary until now, the second electrode of the fuel cell according to the invention likewise comprises a catalyst-free circular region having a radius R2<R1max. Advantageously, 0.5 lm?[R1max?R2]?2 lm applies.

Abstract: There is provided a method for the activation of a fuel cell. An exemplary method comprises operating the fuel cell entirely or partially at least briefly in an electrolysis regimen during galvanic operation.

Abstract: There is provided a method for the activation of a fuel cell. An exemplary method comprises operating the fuel cell entirely or partially at least briefly in an electrolysis regimen during galvanic operation.