Stop method for fuel cell system and fuel cell system

Abstract

A stop method for a fuel cell system including a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction. The stop method includes the steps of stopping supply of hydrogen to the anode, electrically connecting the anode and the cathode via an electrical load, and supplying air to the anode.

1 . A stop method for a fuel cell system that comprises a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction, the stop method comprising the steps of: 
 stopping a supply of hydrogen to the anode;    electrically connecting the anode and the cathode via an electrical load; and    supplying the air to the anode.    
   
   
       2 . The stop method for a fuel cell system according to  claim 1 , wherein: 
 the fuel cell is for a fuel cell powered vehicle; and    the electrical load is electrically powered auxiliaries.    
   
   
       3 . The stop method for a fuel cell system according to  claim 1 , wherein: 
 the fuel cell is for a fuel cell powered vehicle; and    the electrical load is a dummy load for a purging process.    
   
   
       4 . A stop method for a fuel cell system that comprises a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction, and a hydrogen circulation path through which unreacted hydrogen is returned to the anode, the stop method comprising the steps of: 
 stopping a supply of hydrogen to the hydrogen circulation path;    electrically connecting the anode and the cathode via an electrical load when it is determined that a gas pressure in the hydrogen circulation path becomes lower than a predetermined pressure; and    supplying the air to the hydrogen circulation path.    
   
   
       5 . The stop method for a fuel cell system according to  claim 4 , wherein: 
 the fuel cell is for a fuel cell powered vehicle; and    the electrical load is electrically powered auxiliaries.    
   
   
       6 . The stop method for a fuel cell system according to  claim 4 , wherein: 
 the fuel cell is for a fuel cell powered vehicle; and    the electrical load is a dummy load for a purging process.    
   
   
       7 . A fuel cell system comprising: 
 a hydrogen supply path for introducing hydrogen;    an air supply path for introducing air containing oxygen;    a switching path connected between the hydrogen supply path and the air supply path;    a first valve for opening and closing the hydrogen supply path;    a second valve for opening and closing the switching path;    a fuel cell unit in which hydrogen is supplied to an anode from the hydrogen supply path, and air is supplied to a cathode from the air supply path so as to generate electrical power via an electrochemical reaction;    an electrical load electrically connected between the anode and the cathode; and    a controller for controlling opening and closing of the first valve, opening and closing of the second valve, and connection and termination of an electrical connection between the electrical load, and the anode and the cathode.    
   
   
       8 . The fuel cell system according to  claim 7 , wherein: 
 the fuel cell is for a fuel cell powered vehicle; and    the electrical load is electrically powered auxiliaries.    
   
   
       9 . The fuel cell system according to  claim 7 , wherein: 
 the fuel cell is for a fuel cell powered vehicle; and    the electrical load is a dummy load for a purging process.    
   
   
       10 . The fuel cell system according to  claim 7 , further comprising: 
 a hydrogen circulation path through which unreacted hydrogen is returned to the anode; and    a pressure sensor for measuring gas pressure in the hydrogen circulation path and transmitting the gas pressure to the controller.    
   
   
       11 . The fuel cell system according to  claim 10 , wherein: 
 the fuel cell is for a fuel cell powered vehicle; and    the electrical load is electrically powered auxiliaries.    
   
   
       12 . The fuel cell system according to  claim 10 , wherein: 
 the fuel cell is for a fuel cell powered vehicle; and    the electrical load is a dummy load for a purging process.