Pressure relief system for a fuel cell system having a pressurized fuel flow

Abstract

A fuel cell-based system includes an electromechanical pressure relief system to prevent an overpressure condition from damaging the anode circuit of a fuel cell stack or creating a hazardous environment. Upon detection of a fuel flow pressure in a fuel path between a fuel source and the fuel cell stack, the pressure relief system isolates the anode circuit from the fuel path, vents the fuel flow, and shuts down the fuel cell system.

1 . A method usable with a fuel cell-based system, comprising:
 providing a pressurized fuel flow to a fuel cell stack;   detecting a fuel flow pressure provided to the fuel cell stack;   isolating the fuel cell stack from the fuel flow upon detection of the fuel flow pressure provided to the fuel cell stack exceeding a first predefined threshold;   venting a portion of the fuel flow upon detection of the fuel flow pressure provided to the fuel cell stack exceeding a second predefined threshold, the second predefined threshold being greater than the first predefined threshold; and   preventing startup of the fuel cell system after venting the portion of the fuel flow.   
     
     
         2 . The method as recited in  claim 1 , wherein isolating the fuel cell stack comprises controlling communication of power within the fuel cell-based system. 
     
     
         3 . The method as recited in  claim 1 , wherein isolating the fuel cell stack comprises interrupting communication of power to a system controller that controls the fuel cell-based system. 
     
     
         4 . The method as recited in  claim 1 , further comprising:
 diverting a portion of the vented fuel flow;   detecting the diverted fuel flow; and   isolating the fuel cell stack from the pressurized fuel flow provided to the fuel cell stack based upon detection of the diverted fuel flow.   
     
     
         5 . The method as recited in  claim 4 , wherein isolating the fuel cell stack flow based upon detection of the diverted fuel flow comprises interrupting communication of power to a system controller that controls the fuel cell-based system. 
     
     
         6 . The method as recited in  claim 5 , wherein isolating the fuel cell stack from the fuel flow upon detection of the fuel flow pressure provided to the fuel cell stack exceeding the first predefined threshold comprises interrupting communication of power to a system controller that controls the fuel cell-based system. 
     
     
         7 . The method as recited in  claim 6 , further comprising providing a pressure switch to detect the fuel flow pressure provided to the fuel cell stack and to interrupt the communication of power to the system controller upon the detection of the fuel flow pressure provided to the fuel cell stack exceeding the first predefined threshold. 
     
     
         8 . A method usable with a fuel cell-based system, comprising:
 communicating power to a system controller to control the fuel cell-based system;   providing a pressurized fuel flow to a fuel cell stack in the fuel cell-based system;   detecting a fuel flow pressure provided to the fuel cell stack;   activating a pressure switch to interrupt the communication of power to the system controller to isolate the fuel cell stack from the pressurized fuel flow in response to application of a fuel flow pressure to the pressure switch that exceeds a first threshold; and   releasing a portion of the pressurized fuel flow provided to the fuel cell stack in response to the fuel flow pressure provided to the fuel cell stack exceeding a second threshold.   
     
     
         9 . The method as recited in  claim 8 , wherein the second threshold is greater than the first threshold. 
     
     
         10 . The method as recited in  claim 8 , further comprising preventing startup of the fuel cell-based system in response to the release of the portion of the pressurized fuel flow. 
     
     
         11 . The method as recited in  claim 8 , wherein the portion of the pressurized fuel flow is released into a vent path, and the method further comprises:
 detecting the released portion of the pressurized fuel flow in the vent path; and   isolating the fuel cell stack from the pressurized fuel flow provided to the fuel cell stack in response to the detection of the released portion of the pressurized fuel flow in the vent path.   
     
     
         12 . The method as recited in  claim 11 , further comprising preventing startup of the fuel cell-based in response to a detected amount of fuel flow in the vent path exceeding a threshold amount.