US 4,548,874 AGranted

Short protection device for stack of electrolytic cells

AssigneeThe United States of America as represented by the United States Department of Energy

InventorsMurray Katz, Craig R. Schroll

Life of this patent

Estimating the term…

Loading patent…

Abstract

Electrical short protection is provided in an electrolytic cell stack by the combination of a thin, nonporous ceramic shield and a noble metal foil disposed on opposite sides of the sealing medium in a gas manifold gasket. The thin ceramic shield, such as alumina, is placed between the porous gasket and the cell stack face at the margins of the negative end plate to the most negative cells to impede ion current flow. The noble metal foil, for instance gold, is electrically coupled to the negative potential of the stack to collect positive ions at a harmless location away from the stack face. Consequently, corrosion products from the stack structure deposit on the foil rather than on the stack face to eliminate electrical shorting of cells at the negative end of the stack.

Claims10

Dependent claims

An electrical short protection device in combination with a gas seal between a gas supply manifold and a face of an electrolytic cell stack, said stack having opposite ends of negative and positive electrical potential, wherein said gas seal includes a porous sealing medium between marginal portions of the stack face and the manifold, said electrical short protection device comprising:

a generally non-porous electrically insulative shield between the marginal portions of at least two cells in the negative end of the stack and said porous sealing medium;
and
an electrically conductive foil of corrosion resistant material electrically coupled to the negative potential of the cell stack, said foil disposed across the thickness of the porous sealing medium from the electrically insulative shield in general alignment therewith, wherein electrolytically dissolved metal ions preferentially migrate to the foil instead of the face of the fuel cell stack.

Dependencies are inferred from the claim text.