Methods and apparatuses for managing fluids in a fuel cell system

Abstract

A fuel cell system including an anode chamber having a fuel mixture comprising methanol and water, and a diffusion layer, a fuel source in fluid communication with the anode chamber via a conduit, a cathode chamber having a cathode and a diffusion layer, wherein the diffusion layer is in fluid communication with an oxidizer, and a proton conducting, electrical non-conducting membrane electrolyte separating the chambers and positioned substantially adjacent to said diffusion layers. The membrane includes a catalyst exposed to each of the chambers for initiating chemical reactions to produce electricity. The system also includes a first valve for automatically controlling a flow of fuel from the fuel supply cartridge, where the first valve includes a shape memory alloy.

1 - 88 . (canceled)  
   
   
       89 . A method for controlling flow in a fuel cell, comprising: 
 producing electrical energy in the fuel cell; and    actuating a thermally-sensitive actuator based on a temperature of the fuel cell for controlling a flow.    
   
   
       90 . The method according to  claim 89 , wherein said thermally-sensitive actuator increases or decreases said flow.  
   
   
       91 . The method according to  claim 89 , wherein said flow comprises a flow of fuel to the fuel cell or a flow of water to the fuel cell.  
   
   
       92 . The method according to  claim 89 , wherein said actuator comprises a shape memory material, alloy and/or a bimetal material.  
   
   
       93 . The method according to  claim 92 , wherein said bimetal material comprises a nickel and/or titanium alloy.  
   
   
       94 . The method according to  claim 89 , wherein said thermally-sensitive actuator is actuated in response to heat generated by the fuel cell.  
   
   
       95 . A method for controlling a flow in a fuel cell, comprising: 
 producing electrical energy in said fuel cell;    providing a flow of a fluid to a fuel mixture of said fuel cell in response to said production of electrical energy; and    expanding a first material in response to a fuel concentration of said fuel mixture, wherein expansion of said first material controls said flow.    
   
   
       96 . The method according to  claim 95 , wherein said flow comprises a flow of water or a flow of fuel.  
   
   
       97 . The method according to  claim 95 , wherein said first material comprises Nafion.  
   
   
       98 . The method according to  claim 95 , wherein said expansion of said first material increases or decreases said flow.  
   
   
       99 . A method for determining a concentration of fuel in a fuel cell comprising: 
 providing a dimensionally variable first material capable of expansion and contraction in relation to a concentration of fuel in a fuel cell, wherein a conductor is disposed on or within the first material;    flowing an electrical current through said conductor;    measuring an electrical property of said conductor, wherein as fuel concentration changes, the first material expands resulting in a proportionate change to the electrical property of said conductor.    
   
   
       100 . The method according to  claim 99 , wherein the electrical property comprises at least one of resistance, impedance, and conductance.