Semi-passive type fuel cell system

Abstract

A semi-passive fuel cell system is provided. A stack in which a plurality of unit cells are laterally stacked with one another is provided. Each unit cell includes a membrane-electrode assembly and bipolar plates located on both sides of the membrane-electrode assembly. The membrane-electrode assembly includes an electrolyte membrane, a cathode electrode, and an anode electrode. The cathode and anode electrodes, respectively, are formed on each side of the electrolyte membrane. Also provided are a means for supplying fuel and a means for supplying air. Each of the bipolar plates has air paths formed on a surface facing the cathode electrode and extending from an upper end to a lower end of the bipolar plate. The air supply means includes ducts which are respectively installed on an upper end and a lower end of the stack, and includes a means for blowing air through the ducts.

1 . A semi-passive type fuel cell system comprising:
 a stack having a stack upper end, a stack lower end, and a plurality of unit cells laterally stacked with one another, each unit cell including a membrane-electrode assembly and bipolar plates located on both sides of the membrane-electrode assembly, the membrane-electrode assembly having an electrolyte membrane, a cathode electrode, and an anode electrode, the electrolyte membrane having an electrolyte membrane first side surface and an electrolyte membrane second side surface, the cathode electrode being formed on the electrolyte membrane first side surface, the anode electrode being formed on the electrolyte membrane second side surface, the bipolar plates each having a bipolar plate upper end and a bipolar plate lower end;   means for supplying fuel to the stack; and   means for supplying air to the stack,   wherein each of the bipolar plates has air paths formed on a surface facing the cathode electrode and extending from the bipolar plate upper end to the bipolar plate lower end;   wherein the means for supplying air includes a first duct installed on the stack upper end and a second duct installed on the stack lower end, means for blowing air through the first duct and the second duct, and a filter disposed between the means for blowing air and the stack upper end in the first duct; and   wherein the means for blowing air is installed in the first duct.   
     
     
         2 . The fuel cell system as claimed in  claim 1 , wherein the air paths of the bipolar plates are a straight line extending from the stack upper end to the stack lower end. 
     
     
         3 . The fuel cell system as claimed in  claim 1 ,
 wherein the first duct includes a first duct first part and a first duct second part, and   wherein the means for blowing air is installed to supply air from the first duct first part to the first duct second part.   
     
     
         4 . The fuel cell system as claimed in  claim 3 ,
 wherein the first duct first part includes the means for blowing air and the first duct second part covers entirely the stack upper end; and   wherein an air suction opening is formed through an upper wall of the first duct first part directly above the means for blowing air, and an air supply opening for supplying air to the stack is formed through a lower wall of the first duct second part to have an area corresponding to an area of the stack upper end.   
     
     
         5 . The fuel cell system as claimed in  claim 3 ,
 wherein the first duct second part has a first duct second part left end and a first duct second part right end, and   wherein an upper wall of the first duct second part is inclined downwards to have a predetermined inclination angle so that a height of the upper wall gradually decreases from the first duct second part left end to the first duct second part right end.   
     
     
         6 . The fuel cell system as claimed in  claim 5 , wherein the filter has an area corresponding to a widthwise sectional area of an inside space of the first duct, and is installed in a direction perpendicular to air flow. 
     
     
         7 . The fuel cell system as claimed in  claim 5 , wherein the filter is installed at a position corresponding to an end of the stack. 
     
     
         8 . The fuel cell system as claimed in  claim 5 , wherein the filter is formed of a porous material through which air can pass. 
     
     
         9 . The fuel cell system as claimed in  claim 8 , wherein the filter is formed of one selected from the group consisting of polytetrafluoroethylene, silicon resin, polyethylene, polypropylene, and polyethylene terephthalate. 
     
     
         10 . The fuel cell system as claimed in  claim 5 , wherein the filter is supported by a support plate installed in the first duct. 
     
     
         11 . The fuel cell system as claimed in  claim 1 ,
 wherein the second duct includes a second duct left end and a second duct right end, and   wherein an air receiving opening for receiving air having passed through the stack is formed through an upper wall of the second duct to have an area corresponding to an area of the stack lower end, and an air discharge opening for discharging air to the outside is formed through the second duct right end.   
     
     
         12 . The fuel cell system as claimed in  claim 11 , wherein a lower wall of the second duct is inclined downwards to have a predetermined inclination angle so that a height of the lower wall gradually increases from the second duct left end to the second duct right end. 
     
     
         13 . The fuel cell system as claimed in  claim 12 , wherein the lower wall of the second duct is inclined at the same inclination angle as the upper wall of the first duct. 
     
     
         14 . The fuel cell system as claimed in  claim 3 , wherein the upper wall of the first duct second part has a uniform height. 
     
     
         15 . The fuel cell system as claimed in  claim 14 , wherein the lower wall of the second duct has a uniform height. 
     
     
         16 . The fuel cell system as claimed in  claim 1 , wherein the means for blowing air includes a blower or a fan. 
     
     
         17 . The fuel cell system as claimed in  claim 1 , wherein the fuel cell system is a direct methanol fuel cell system or a polymer electrolyte membrane fuel cell system.