Fuel Cell System and Operation Method Thereof

Abstract

A fuel cell system ( 100 ) comprising: a fuel cell ( 1 ) configured to generate electric power using an oxidizing gas and a fuel gas; a recovered water tank ( 3 ) configured to store water recovered from an exhaust gas discharged from the fuel cell; a water storage tank ( 4 ) configured to store water used as cooling water for cooling the fuel cell; a water feed flow path (g) through which the water stored in the recovered water tank is supplied to the water storage tank; a pump ( 8 ) configured to force water to flow from the recovered water tank to the water storage tank within the water feed flow path; a water purifier ( 7 ) configured to purify the water forcibly flowed by said pump in the water feed flow path by means of a built-in TOC absorber ( 7 a ) before the water is supplied to the water storage tank; and a controller ( 101 ), wherein the controller controls the pump so as to operate in a stop period of the fuel cell system such that water moves in the water feed flow path.

1 . A fuel cell system comprising:
 a fuel cell configured to generate electric power using an oxidizing gas and a fuel gas;   a recovered water tank configured to store water recovered from at least either of the oxidizing gas and fuel gas discharged from said fuel cell;   a purified water tank configured to store water used as a cooling water for cooling said fuel cell;   a water feed flow path through which the water stored in said recovered water tank is supplied to said purified water tank;   a pump configured to force water to flow from said recovered water tank to said purified water tank within said water feed flow path;   a water purifier configured to purify, in said water feed flow path, the water forced to flow by said pump, using a TOC absorber incorporated in said water purifier before the water is supplied to said purified water tank; and   a controller,   wherein said controller controls said pump so as to periodically operate in a stop period of said fuel cell system in such a cycle that propagation of bacteria can be restrained, thereby periodically moving water within said water feed flow path.   
     
     
         2 - 3 . (canceled) 
     
     
         4 . The fuel cell system according to  claim 1 , wherein said controller controls said pump so as to periodically operate in the stop period in a cycle of no less than 72 hours but no more than 168 hours, thereby periodically moving the water within said water feed flow path. 
     
     
         5 . The fuel cell system according to  claim 1 , further comprising, as said purified water tank, a cooling water tank for storing the cooling water. 
     
     
         6 . The fuel cell system according to  claim 5 , further comprising a second water feed flow path through which the water stored in said cooling water tank is supplied to said recovered water tank,
 wherein said controller controls said pump so as to operate in the stop period of said fuel cell system to circulate water between said cooling water tank and said recovered water tank, passing through said water feed flow path and said second water feed flow path.   
     
     
         7 . The fuel cell system according to  claim 1 , further comprising a cooling water tank configured to store the cooling water, in addition to said purified water tank,
 wherein the water stored in said purified water tank can be supplied to said cooling water tank.   
     
     
         8 . The fuel cell system according to  claim 7 , further comprising a second pump configured to supply the water stored in said purified water tank to said cooling water tank. 
     
     
         9 . The fuel cell system according to  claim 7 , further comprising a second water feed flow path through which the water stored in said cooling water tank is supplied to said recovered water tank,
 wherein said controller controls said pump so as to operate in the stop period of said fuel cell system to circulate water between said purified water tank, said cooling water tank and said recovered water tank, passing through said water feed flow path and said second water feed flow path.   
     
     
         10 . The fuel cell system according to  claim 7 , further comprising a third water feed flow path through which the water stored in said purified water tank is supplied to said recovered water tank,
 wherein said controller controls said pump so as to operate in the stop period of said fuel cell system to circulate water between said purified water tank and said recovered water tank, passing through said water feed flow path and said third water feed flow path.   
     
     
         11 . The fuel cell system according to  claim 1 , wherein said controller controls said pump so as to operate in the stop period of said fuel cell system such that where P1 represents the water feeding ability of said pump per unit time, T1 represents the operating time of said pump, and V1 represents the capacity of said TOC absorber, P1, T1 and V1 satisfy P1×T1≧V1. 
     
     
         12 . The fuel cell system according to  claim 1 , wherein said water purifier further has an ion exchanger.