Fuel cell system and method for controlling same

Abstract

A fuel cell system 100 includes: a fuel cell 1 for generating a power by causing an electrochemical reaction between an oxidant gas supplied to an oxidant electrode 34 and a fuel gas supplied to a fuel electrode 67; a fuel gas supplier HS for supplying the fuel gas to the fuel electrode 67; and a controller 40 for controlling the fuel gas supplier HS to thereby supply the fuel gas to the fuel electrode 67, the controller 40 being configured to implement a pressure change when an outlet of the fuel electrode 67 side is closed, wherein based on a first pressure change pattern for implementing the pressure change at a first pressure width ΔP1, the controller 40 periodically changes a pressure of the fuel gas at the fuel electrode 67.

1 . A fuel cell system comprising:
 a fuel cell configured to generate electric power by causing an electrochemical reaction between an oxidant gas supplied to an oxidant electrode and a fuel gas supplied to a fuel electrode;   a fuel gas supplier configured to supply the fuel gas to the fuel electrode of the fuel cell;   an output takeout device configured to take out an output from the fuel cell; and   a controller configured to control the output takeout device to thereby take out from the fuel cell, an output corresponding to a required load required for the fuel cell system, and to control the fuel gas supplier to thereby supply the fuel gas to the fuel electrode in such a manner as to change a pressure of the fuel gas at the fuel electrode with a predetermined pressure change range, wherein the controller is programmed to set the pressure change range such that the pressure change range in a case where the required load is high is larger than the pressure change range in a case where the required load is low.   
     
     
         2 . The fuel cell system according to  claim 1 , wherein the controller sets an operation pressure of the fuel cell such that the higher the required load is, the higher the operation pressure is. 
     
     
         3 . The fuel cell system according to  claim 1 , wherein the controller sets an upper limit pressure and a lower limit pressure of the pressure of the fuel gas at the fuel electrode based on an operation pressure of the fuel cell, and change the pressure of the fuel gas at the fuel electrode between the upper limit pressure and the lower limit pressure to thereby change the pressure of the fuel gas at the fuel electrode with the predetermined pressure change range. 
     
     
         4 . The fuel cell system according to  claim 3 , wherein a rate of increase of the lower limit pressure relative to an increase of the required load is set such that the rate of increase of the lower limit pressure in a case where the required load is high is larger than the rate of increase of the lower limit pressure in a case where the required load is low. 
     
     
         5 . A fuel cell system comprising:
 a fuel cell configured to generate electric power by causing an electrochemical reaction according to a load of the fuel cell system between an oxidant gas supplied to an oxidant electrode and a fuel gas supplied to a fuel electrode and to consume the fuel gas in the fuel electrode;   a non-recirculating type fuel gas system comprising:
 a fuel gas supplier configured to supply the fuel gas to an inlet of the fuel electrode of the fuel cell: 
 a capacity device provided on an outlet side of the fuel electrode of the fuel cell; and 
 a purge valve provided on the outlet side of the fuel electrode of the fuel cell; and 
   a pressure increase-decrease controller programmed to have a pressure of the fuel gas at the fuel electrode increased with an increase of the load, while controlling the fuel gas supplier to increase/decrease the pressure of the fuel gas at the fuel electrode with a predetermined pressure increase/decrease range at a given load, wherein the pressure increase-decrease controller sets, in a case where the load is high, a large pressure increase/decrease range as compared to a case where the load is low.