Method and apparatus for water management of a fuel cell system

Abstract

A method and apparatus for water management in a direct oxidation fuel cell system includes a direct oxidation fuel cell, including: a housing surrounding an anode, a cathode, a protonically conductive electronically non-conductive membrane electrolyte disposed between the anode and the cathode, a current collector, and a gas-permeable liquid-impermeable membrane disposed on a side of the cathode opposite the electrolyte. Excess water accumulation is removed from an area between the membrane electrolyte and the gas-permeable liquid-impermeable membrane by a pressure differential generated, preferably, by a pump. The pressure differential draws air to the surface of, into, or through the cathode diffusion layer. The pump can be driven by the electricity generated by the fuel cell.

1 . A system comprising: 
 a direct oxidation fuel cell, comprising a housing surrounding an MEA, a current collector disposed on the outside of the MEA to collect and conduct electrical current to a load, and a gas-permeable liquid-impermeable membrane disposed on a cathode-side outer surface of the current collector, wherein said MEA comprises an anode aspect, a cathode aspect, and a PCM disposed between the anode aspect and the cathode aspect;    a source of fuel in communication with the anode aspect;    a source of oxygen in communication with the cathode aspect, so as to produce electricity-generating reactions, comprising anodic disassociation of a fuel and water mixture to produce carbon dioxide, protons and electrons and a cathodic combination of protons, electrons and oxygen to produce water; and    a pump in fluid communication with an area between the PCM and the gas-permeable liquid-impermeable membrane, to remove excess water produced at the cathode aspect, wherein said fluid communication comprises a hydrophilic material.    
   
   
       2 . The system of  claim 1 , wherein the hydrophilic material is a hydrophilic fabric, foam, cotton thread, or treated fabric, hydrophilic polymer, hydrophilic polyester, or combinations thereof.  
   
   
       3 . The system of  claim 1 , wherein the cathode aspect further comprises a cathode capillary material disposed between the gas-permeable liquid-impermeable membrane and a cathode diffusion layer, wherein the cathode diffusion layer is adjacent the PCM.  
   
   
       4 . The system of  claim 3 , wherein the cathode capillary material is a hydrophilic material.  
   
   
       5 . The system of  claim 4 , wherein the hydrophilic material is a hydrophilic fabric, foam, cotton thread, or treated fabric, hydrophilic polymer, hydrophilic polyester, or combinations thereof.  
   
   
       6 . The system of  claim 1 , wherein the pump is in fluid communication with more than one fuel cell of a fuel cell stack.