Alkaline membrane fuel cells and apparatus and methods for supplying water thereto
A device to produce electricity by a chemical reaction without the addition of liquid electrolyte comprises an anode electrode, a polymer membrane electrolyte fabricated to conduct hydroxyl (OH—) ions, the membrane being in physical contact with the anode electrode on a first side of the membrane, and a cathode electrode in physical contact with a second side of the membrane. The anode electrode and cathode electrode contain catalysts, and the catalysts are constructed substantially entirely from non-precious metal catalysts. Water may be transferred to the cathode side of the membrane from an external source of water.
1. An alkaline membrane fuel cell comprising:
an anode electrode;
a polymer membrane electrolyte configured to conduct hydroxyl (OH—) ions, the membrane being in physical contact with the anode electrode on a first side of the membrane;
a cathode electrode in physical contact with a second opposite side of the membrane;
a cathode chamber having a cathode exhaust stream and a cathode inlet stream;
wherein the fuel cell is configured and designed to transfer water effectively from the anode electrode through the membrane to the cathode electrode; and,
wherein the fuel cell so configured does not require an external source of water for cell operation;
the alkaline membrane fuel cell further comprising a water exchanger operatively connected with the fuel cell and disposed to transfer water from the cathode exhaust stream to the cathode inlet stream; and
wherein the water exchanger includes a membrane, the membrane being of high water permeability and low gas permeability to enable transport of water from the high relative humidity, warm cathode exhaust stream to the inlet stream of lower temperature and lower water content.