Fuel cell arrangement for determining the overvoltage of a working electrode in a fuel cell, - comprising a working electrode, a counter electrode and a reference electrode, - comprising a polymer electrolyte membrane with a layer thickness l m , in which the continuous working electrode is arranged on one side and the counter electrode is arranged on the other side, - in which the counter electrode has at least one side edge and at least one convex curved tip with a local radius R a , - in which the electrolyte membrane surface has an electrode-free area next to the counter electrode and opposite the working electrode, - in which the reference electrode is arranged on the electrolyte membrane surface opposite the working electrode in the area of the electrode-free area and right next to the convex curved tip of the counter electrode, - in which the reference electrode is arranged at a distance in the range L gap to 100 L gap from the convex curved tip of the counter electrode and - in which the minimum distance L gap between the reference electrode and the convex curved edge area of the counter electrode is given by L gap = 3 ⋅ L 1 , r with L 1 , r ≅ πλ D 2 ln 67 18 R a / λ D 7 / 45 − 1 and λ D = σ m b ox l m 2 j ox 0 with σ m = ionic conductivity of the electrolyte membrane (Ω -1 cm -1 ), b ox = Tafel slope of the half cell for the electrochemical reaction of the working electrode (V), l m = membrane layer thickness (cm), j 0 ox = exchange current density of the catalyst of the working electrode per unit of electrode surface in (A cm -2 ), and R a = local radius of the convex curved tip of the counter electrode (cm), which is closest to the reference electrode. - comprising a working electrode, a counter electrode and a reference electrode, - comprising a polymer electrolyte membrane with a layer thickness l m , in which the continuous working electrode is arranged on one side and the counter electrode is arranged on the other side, - in which the counter electrode has at least one side edge and at least one convex curved tip with a local radius R a , - in which the electrolyte membrane surface has an electrode-free area next to the counter electrode and opposite the working electrode, - in which the reference electrode is arranged on the electrolyte membrane surface opposite the working electrode in the area of the electrode-free area and right next to the convex curved tip of the counter electrode, - in which the reference electrode is arranged at a distance in the range L gap to 100 L gap from the convex curved tip of the counter electrode and - in which the minimum distance L gap between the reference electrode and the convex curved edge area of the counter electrode is given by L gap = 3 ⋅ L 1 , r with L 1 , r ≅ πλ D 2 ln 67 18 R a / λ D 7 / 45 − 1 and λ D = σ m b ox l m 2 j ox 0 with σ m = ionic conductivity of the electrolyte membrane (Ω -1 cm -1 ), b ox = Tafel slope of the half cell for the electrochemical reaction of the working electrode (V), l m = membrane layer thickness (cm), j 0 ox = exchange current density of the catalyst of the working electrode per unit of electrode surface in (A cm -2 ), and R a = local radius of the convex curved tip of the counter electrode (cm), which is closest to the reference electrode. σ m = ionic conductivity of the electrolyte membrane (Ω -1 cm -1 ), b ox = Tafel slope of the half cell for the electrochemical reaction of the working electrode (V), l m = membrane layer thickness (cm), j 0 ox = exchange current density of the catalyst of the working electrode per unit of electrode surface in (A cm -2 ), and R a = local radius of the convex curved tip of the counter electrode (cm), which is closest to the reference electrode. <EOS>