Method for controlling a fuel cell
First Claim
1. A method for controlling a fuel cell having a fuel cell stack to which a reformed fuel and an oxidizing agent are supplied, said method comprising the steps of:
- generating electric power while keeping said fuel cell stack at a voltage having a constant value;
detecting an output current Is from said fuel cell stack, said output current Is being proportional to consumed amounts of said reformed fuel and said oxidizing agent;
calculating the difference between the value of said output current Is detected and a predetermined current value Io ; and
varying the amount of said fuel and/or oxidizing agent to be supplied in accordance with said difference so as to minimize said difference by reducing the amount supplied when Is >
Io and increasing the amount supplied when Is <
Io, whereby electric power is generated in a stable manner.
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Accused Products
Abstract
In order to control a fuel cell having a fuel cell stack to which reformed fuel and oxidizing agent are supplied, an output current from the fuel cell is detected while the voltage of the fuel cell is maintained at a constant voltage and the amount of the fuel and/or the oxidizing agent is controlled in accordance with the detected output current to stably generate electric power. At least one of a plurality of unit cells constituting the fuel cell stack is used as a monitoring cell having a current-voltage characteristic curve which is lower than that of the other unit cells, and an output current from the monitoring cell is detected while the voltage of this cell is maintained at a constant voltage, and the supplied amount of the fuel and/or the oxidizing agent is controlled in accordance with the detected current value to stably generate electric power output.
217 Citations
10 Claims
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1. A method for controlling a fuel cell having a fuel cell stack to which a reformed fuel and an oxidizing agent are supplied, said method comprising the steps of:
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generating electric power while keeping said fuel cell stack at a voltage having a constant value; detecting an output current Is from said fuel cell stack, said output current Is being proportional to consumed amounts of said reformed fuel and said oxidizing agent; calculating the difference between the value of said output current Is detected and a predetermined current value Io ; and varying the amount of said fuel and/or oxidizing agent to be supplied in accordance with said difference so as to minimize said difference by reducing the amount supplied when Is >
Io and increasing the amount supplied when Is <
Io, whereby electric power is generated in a stable manner. - View Dependent Claims (2, 3, 4, 5)
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6. A method for controlling a fuel cell having a fuel cell stack comprised of a plurality of unit cells to which a reformed fuel and an oxidizing agent are supplied, said method comprising the steps of:
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using at least one of said plurality of unit cells constituting said fuel cell stack as a monitoring cell, said monitoring cell, for a given output current Is through said stack, having a voltage thereacross which is less than the voltage across said remaining unit calls for said given output current; generating electric power while keeping said monitoring cell at a voltage having a constant value; detecting said output current from said fuel cell stack, said output current being proportional to consumed amounts of said reformed fuel and said oxidizing agent; calculating the difference between the value of said output current Is and a predetermined current value Io ; and varying the amount of said fuel and/or oxidizing agent to be supplied in accordance with said difference so as to minimize said difference by reducing the amount supplied when Is >
Io and increasing the amount supplied when Is <
Io, whereby electric power is generated in a stable manner. - View Dependent Claims (7, 8, 9, 10)
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Specification