US 6,635,375 B1Granted

Planar solid oxide fuel cell with staged indirect-internal air and fuel preheating and reformation

AssigneeThe United States of America as represented by the United States Department of Energy

InventorsRodney A. Geisbrecht, Mark C. Williams

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Abstract

A solid oxide fuel cell arrangement and method of use that provides internal preheating of both fuel and air in order to maintain the optimum operating temperature for the production of energy. The internal preheat passes are created by the addition of two plates, one on either side of the bipolar plate, such that these plates create additional passes through the fuel cell. This internal preheat fuel cell configuration and method reduce the requirements for external heat exchanger units and air compressors. Air or fuel may be added to the fuel cell as required to maintain the optimum operating temperature through a cathode control valve or an anode control valve, respectively. A control loop comprises a temperature sensing means within the preheat air and fuel passes, a means to compare the measured temperature to a set point temperature and a determination based on the comparison as to whether the control valves should allow additional air or fuel into the preheat or bypass manifolds of the fuel cell.

Claims14

Dependent claims

A solid oxide fuel cell, comprising:

a symmetric hollow frame supporting a first membrane electrode assembly (MEA) and a second MEA;
said first and said second MEAs having a cathode layer positioned such that a cathode side of said MEA is exposed within the fuel cell and an anode layer positioned such that an anode side of said MEA is exposed within the fuel cell, said cathode and said anode layers are horizontally separated by an electrolyte layer;
said first and said second MEAs are separated by a bipolar plate (BPP);
a cathode separator plate separates said first MEA on said cathode side from said BPP;
an anode separator plate separates said second MEA on said anode side from said BPP;
and where
said cathode separator plate, said BPP, and said anode separator plate are arranged between said first and said second MEAs to define an air preheat pass, a reactive air pass, a fuel preheat pass, and a fuel reactive pass;
a means for determining an air temperature located at an exit end of said air preheat pass;
a means for comparing and controlling said air temperature to a set point air temperature;
a cathode control valve to add air into said reactive air pass from an air bypass flow;
a means for determining a fuel temperature located at an exit end of said fuel preheat pass;
a means for comparing and controlling said fuel temperature to a set point fuel temperature;
and
an anode control valve to add fuel into said reactive fuel pass from a fuel bypass flow.

11 more elements

Dependencies are inferred from the claim text.