Process for operating a PEM fuel cell installation

Abstract

A process for operating a PEM fuel cell installation includes providing at least one PEM fuel cell module having an inlet valve for hydrogen H 2 and an inlet valve for oxygen O 2 . In order to switch off the PEM fuel cell module, the oxygen O 2 inlet valve is closed in a first step, and the hydrogen H 2 inlet valve is closed in a second step when a predetermined oxygen O 2 partial pressure at a cathode part of the PEM fuel cell module is reached. Reliable operation of the PEM fuel cell installation is guaranteed by this measure.

We claim:  
     
       1. A process for operating a PEM fuel cell installation, which comprises: providing at least one PEM fuel cell module with a device for adjusting a supply of hydrogen and a supply of oxygen; and 
       suspending the supply of hydrogen and the supply of oxygen by suspending the supply of oxygen in a first step and suspending the supply of hydrogen in a second step when an oxygen partial pressure of about 0.5 bar at a cathode part of the PEM fuel cell module is reached.  
     
     
       2. The process according to  claim 1 , which comprises measuring the oxygen partial pressure indirectly through static air pressure. 
     
     
       3. A process for operating a PEM fuel cell installation, which comprises: 
       providing at least one PEM fuel cell module with a device for adjusting a supply of hydrogen and a supply of oxygen; and  
       suspending the supply of hydrogen and the supply of oxygen by suspending the supply of oxygen in a first step and suspending the supply of hydrogen in a second step when a predetermined oxygen partial pressure at a cathode part of the PEM fuel cell module is reached;  
       measuring a further oxygen partial pressure indirectly through static air pressure.  
     
     
       4. A process for operating a PEM fuel cell installation, which comprises: 
       providing at least one PEM fuel cell module with a device for adjusting a supply of hydrogen and a supply of oxygen; and  
       suspending the supply of hydrogen and the supply of oxygen by suspending the supply of oxygen in a first step and suspending the supply of hydrogen in a second step;  
       supplying the oxygen in the form of compressed air;  
       measuring an oxygen partial pressure indirectly through static air pressure.