Fuel cell system

Abstract

The fuel cell system comprises a fuel cell having an anode supplied with fuel gas and a cathode supplied with oxidizing agent gas, a water penetration membrane-type moistening device for collecting moisture contained in cathode off gas discharged from a cathode exit of the fuel cell and moistening oxidizing agent gas, and a moisture regulating means for regulating moisture contained in cathode off gas between the cathode exit of the fuel cell and the water penetration membrane-type moistening device, wherein when operating the fuel cell at more than a predetermined rated load of the fuel cell, moisture contained in cathode off gas is reduced by the moisture regulating means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the fuel cell system of an embodiment of the present invention.

FIG. 2 is a schematic view of the fuel cell system of an embodiment of the present invention.

FIG. 3 is a schematic view of the fuel cell system of a comparison embodiment of the present invention.

FIG. 4 is I-V characteristic curves when the embodiment of the present invention is used.

FIG. 5 is a block diagram of the fuel cell system of an embodiment of the present invention.

FIG. 6 is a block diagram of the fuel cell system of an embodiment of the present invention.

Claims

1. A fuel cell system comprising a fuel cell for oxidizing fuel gas, reducing oxidizing agent gas, thereby generating power and a water penetration membrane-type moistening device for collecting moisture contained in cathode off gas composed of said reduced oxidizing agent gas and moistening said oxidizing agent gas before reduction, wherein moisture regulating means for regulating said moisture contained in said cathode off gas is installed on a pipe connected to said fuel cell and when said fuel cell is operated at more than a predetermined rated load of said fuel cell, said moisture contained in said cathode off gas is reduced by said moisture regulating means.

2. A fuel cell system according to claim 1, wherein said moisture regulating means has a cathode off gas bypass line for distributing and discharging said cathode off gas outside said system.

3. A fuel cell system according to claim 1, wherein said cathode off gas bypass line is equipped with flow rate regulating means.

4. A fuel cell system according to claim 3, further comprising means for detecting a cell voltage of said fuel cell, wherein according to said cell voltage, said means controls stepwise said flow rate regulating means for said cathode off gas.

5. A fuel cell system according to claim 3, further comprising means for detecting a temperature of said fuel cell, wherein according to said temperature, said means controls stepwise said flow rate regulating means for said cathode off gas.

6. A fuel cell system according to claim 3, further comprising means for detecting dew point temperatures of said fuel gas and/or said oxidizing agent gas, wherein according to detected values of said dew point temperature detection means, said means controls stepwise said flow rate regulating means for said cathode off gas.

7. A fuel cell system comprising a fuel cell for oxidizing fuel gas, reducing oxidizing agent gas, thereby generating power and a water penetration membrane-type moistening device for collecting moisture contained in cathode off gas composed of said reduced oxidizing agent gas and moistening said oxidizing agent gas before reduction, wherein a cathode off gas bypass line for distributing and discharging said cathode off gas outside said system is installed on a pipe connected to said fuel cell, and said cathode off gas bypass line is equipped with flow rate regulating means, and when said fuel cell is operated at more than a predetermined rated load of said fuel cell, according to a power generation load current of said fuel cell, a discharging rate of cathode off gas from said cathode off gas bypass line is changed.

8. A fuel cell system comprising a fuel cell for oxidizing fuel gas, reducing oxidizing agent gas, thereby generating power and a water penetration membrane-type moistening device for collecting moisture contained in cathode off gas composed of said reduced oxidizing agent gas and moistening said oxidizing agent gas before reduction, wherein a cathode off gas bypass line for distributing and discharging said cathode off gas outside said system is installed on a pipe connected to said fuel cell, and said cathode off gas bypass line is equipped with flow rate regulating means, and when said fuel cell is operated at more than a predetermined rated load of said fuel cell, a flow rate of said cathode off gas into said cathode off gas bypass line is regulated by said flow rate regulating means.