(US6676340-N)      Electrolytic cell short protection device utilises a thin non porous ceramic shield and a noble metal foil on opposite sides of the sealing medium in a gas manifold gasket. The ceramic shield eg alumina is between the gasket and the cell stack face at the margins of the negative end plate to the most negative cells. The foil, e.g. made of Au is connected to the negative potential of the stack to collect positive ions away from the stack face, corrosion prods which form, depositing on the foil.    USE/ADVANTAGE -   Fuel cells etc operating in high and low temp. corrosive environments, esp molten metal carbonate electrolyte cells. The amt. of expensive corrosion resistant material is minimal. (14pp)n    (JP93058236-B)      An electrolytic cell stack, having opposed ends of negative and positive electrical potential, has a gas seal between a gas supply manifold and a face of the cell stack including a porous sealing medium between their marginal portions. An electrical short protection device combined with the gas seal comprises (a) a nonporous electrically insulating shield between the edges of at least two cells at the negative end of the stack and the porous sealing medium; and (b) an electroconductive foil of corrosion resistant material, electrically coupled to the negative potential of the cell stack, aligned with the shield but on the opposite side of the porous sealing medium. Electrolytically dissolved metal ions pref. migrate to the foil instead of to the face of the cell stack.    ADVANTAGE -   The short protection device prevents plating onto the stack, preventing shorting for over 2000 hrs. operation under conditions where an unprotected stack shorted after 200-300 hr. It uses only min. amts. expensive noble metals. (J61133574-A)    (DE3542324-C2)      The electrical short-circuit device has a gas seal between a gas supply line and one end face of a fuel cell or electrolyte cell stack, with negative and positive potentials at the opposite ends of the latter. The gas seal uses a porous sealing medium between the gas line and the edge of the stack, with a non-porous electrical screen between the edges of at least 2 cells at the negative end of the stack and the porous sealing medium.    A conductive foil of a corrosion-resistant material is connected to the negative potential of the cell stack and fed to a point on the opposite side of the porous sealing medium, facing the electrical screen so that the metal ions move towards the foil instead of to the end face.    ADVANTAGE -   Uncomplicated low-cost device for providing short-circuit protection of fuel cell stack.