Abstract: A base plate assembly for an electrochemical cell stack includes a bottom end plate defining a fuel inlet port, a fuel outlet port, and an oxidant port. The base plate assembly further includes a high strength sealing plate including openings that align with the fuel inlet port, the fuel outlet port, and the oxidant port, and a plurality of tubes located between the bottom end plate and the high strength sealing plate. The tubes are configured to yield to reduce transfer of mechanical stress from the high strength sealing plate to the bottom end plate.

Abstract: A top compression plate assembly for an electrochemical cell stack includes a top end plate configured to interface with a top end of a stack of electrochemical cells, a top compression plate positioned on the top end plate, and a plurality of springs coupled to a periphery of the top compression plate. The springs are configured to cause the top compression plate to exert a compressive force on the top end plate.

Abstract: A method of operating a solid oxide electrolysis cell (SOEC) system at partial load, the SOEC system including a plurality of branches each including at least one SOEC stack, includes determining a thermally neutral target voltage and cycling an ON phase and an OFF phase for each of the branches such that the SOEC system operates at an average operating power equal to a chosen percentage of the operating power at the thermally neutral target voltage. In the ON phase, the SOEC stacks in a given branch operate at the thermally neutral target voltage, and in the OFF phase, the SOEC stacks in the given branch are unloaded to an open circuit voltage and operate at 0% of rated power. The frequency of OFF phases for each branch is determined such that stronger or healthier branches have a lower frequency of OFF cycles than weaker or less healthy branches.

Abstract: A method of operating a solid oxide electrolysis cell (SOEC) system at partial load, where the SOEC system includes a plurality of branches electrically connected in parallel, and each branch includes at least one SOEC stack. The method includes determining a thermally neutral target voltage below which operation is endothermic and above which operation is exothermic; and executing pulse width modulation current control by cycling an ON phase and an OFF phase for each branch such that the SOEC system operates at an average operating power equal to a chosen percentage of the operating power at the thermally neutral target voltage. In the ON phase, all of the SOEC stacks in a branch operate at the thermally neutral target voltage, and in the OFF phase, all of the SOEC stacks in the branch operate at 0% power. Each branch is configured to be operated independently of the other branches.

Abstract: A fuel cell system includes a fuel cell module having an inlet and an outlet. The fuel cell module receives a fuel stream including gaseous fuel and expels a depleted fuel stream. The system also includes an exhaust processing module disposed relative to the fuel cell module such that waste heat from the fuel cell module is usable by the exhaust processing module. The system is configured to direct a first portion of the depleted fuel stream to the exhaust processing module, where the depleted fuel stream includes depleted fuel and at least one gaseous byproduct including oxygen and carbon dioxide. The exhaust processing module subjects the first portion of the depleted fuel stream to co-electrolysis using the waste heat from the fuel cell module to produce a fuel-enriched stream. The system is configured to direct the fuel-enriched stream to the inlet of the fuel cell module.

Abstract: A solid oxide fuel cell system includes a first fuel cell stack including a first anode section and a first cathode section. The first anode section is configured to receive an input stream including fuel, and to output a first output stream including residual fuel and water. A second fuel cell stack includes a second anode section and a second cathode section. The second anode section is configured to receive a mixed stream and to output a second output stream including residual fuel and water. Each of the first and second cathode section is configured to receive inlet air and to output exhaust air. A separating junction is configured to receive and separate the second output stream into a recycle stream and an exhaust stream. A combining junction is configured to receive the first output stream and the recycle stream, and to combine these streams to output the mixed stream.

Abstract: A base plate assembly for an electrochemical cell stack includes a bottom end plate defining a fuel inlet port, a fuel outlet port, and an oxidant port. The base plate assembly further includes a high strength sealing plate including openings that align with the fuel inlet port, the fuel outlet port, and the oxidant port, and a plurality of tubes located between the bottom end plate and the high strength sealing plate. The tubes are configured to yield to reduce transfer of mechanical stress from the high strength sealing plate to the bottom end plate.

Abstract: An electrochemical cell unit comprises a first electrochemical cell comprising a first oxidant electrode and a first fuel electrode, and a second electrochemical cell comprising a second oxidant electrode and a second fuel electrode. An interconnect interposed between the first electrochemical cell and the second electrochemical cell. The interconnect comprises an interconnect main body defining a longitudinal channel along a longitudinal axis thereof. The interconnect main body includes a plurality of corrugations defining a plurality of fuel channels on a first surface of the interconnect main body facing the first electrochemical cell, and a plurality of oxidant channels on a second surface of the interconnect main body facing the second electrochemical cell. Each of the plurality of fuel channels and the plurality of oxidant channel positioned around the longitudinal channel.

Abstract: A top compression plate assembly for an electrochemical cell stack includes a top end plate configured to interface with a top end of a stack of electrochemical cells, a top compression plate positioned on the top end plate, and a plurality of springs coupled to a periphery of the top compression plate. The springs are configured to cause the top compression plate to exert a compressive force on the top end plate.

Abstract: A fuel cell system including a fuel cell module comprising an anode section configured to output an anode exhaust stream, a first junction configured to split the anode exhaust stream into an anode recycle stream and a system outlet stream, and an ejector. The ejector comprises a low pressure inlet configured to receive a suction stream comprising a first portion of the anode recycle stream, a motive inlet configured to receive a motive stream comprising a second portion of the anode recycle stream, and an outlet configured to output an ejector output stream. The anode section is configured to receive an anode input stream that comprises the ejector output stream.

Abstract: A fuel cell system includes a fuel cell module having an inlet and an outlet. The fuel cell module receives a fuel stream including gaseous fuel and expels a depleted fuel stream. The system also includes an exhaust processing module disposed relative to the fuel cell module such that waste heat from the fuel cell module is usable by the exhaust processing module. The system is configured to direct a first portion of the depleted fuel stream to the exhaust processing module, where the depleted fuel stream includes depleted fuel and at least one gaseous byproduct including oxygen and carbon dioxide. The exhaust processing module subjects the first portion of the depleted fuel stream to co-electrolysis using the waste heat from the fuel cell module to produce a fuel-enriched stream. The system is configured to direct the fuel-enriched stream to the inlet of the fuel cell module.

Abstract: An electrochemical cell stack comprises a plurality of electrochemical cell units, each comprising a cathode, an anode, and an electrolyte, and also comprises a plurality of interconnects. An interconnect is disposed between adjacent electrochemical cell units and defines a longitudinal channel having circumferential corrugations defined therearound. A fuel channel is defined between each anode and a respective adjacent interconnect, the fuel channel having fuel inlet and outlet. An oxidant channel is defined between each cathode and a respective adjacent interconnect, the oxidant channel having an oxidant inlet and outlet. The plurality of electrochemical cell units and interconnects include a first electrochemical cell unit, a first interconnect adjacent the first electrochemical cell unit, a second electrochemical cell unit adjacent the first interconnect, and a second interconnect adjacent the second electrochemical cell unit.

Abstract: A method of operating a solid oxide electrolysis cell (SOEC) system at partial load, where the SOEC system includes a plurality of branches electrically connected in parallel, and each branch includes at least one SOEC stack. The method includes determining a thermally neutral target voltage below which operation is endothermic and above which operation is exothermic; and executing pulse width modulation current control by cycling an ON phase and an OFF phase for each branch such that the SOEC system operates at an average operating power equal to a chosen percentage of the operating power at the thermally neutral target voltage. In the ON phase, all of the SOEC stacks in a branch operate at the thermally neutral target voltage, and in the OFF phase, all of the SOEC stacks in the branch operate at 0% power. Each branch is configured to be operated independently of the other branches.

Abstract: An electrochemical cell stack comprises a plurality of electrochemical cell units, each comprising a cathode, an anode, and an electrolyte, and also comprises a plurality of interconnects. An interconnect is disposed between adjacent electrochemical cell units and defines a longitudinal channel having circumferential corrugations defined therearound. A fuel channel is defined between each anode and a respective adjacent interconnect, the fuel channel having fuel inlet and outlet. An oxidant channel is defined between each cathode and a respective adjacent interconnect, the oxidant channel having an oxidant inlet and outlet. The plurality of electrochemical cell units and interconnects include a first electrochemical cell unit, a first interconnect adjacent the first electrochemical cell unit, a second electrochemical cell unit adjacent the first interconnect, and a second interconnect adjacent the second electrochemical cell unit.

Abstract: An electrochemical cell unit comprises a first electrochemical cell comprising a first oxidant electrode and a first fuel electrode, and a second electrochemical cell comprising a second oxidant electrode and a second fuel electrode. An interconnect interposed between the first electrochemical cell and the second electrochemical cell. The interconnect comprises an interconnect main body defining a longitudinal channel along a longitudinal axis thereof. The interconnect main body includes a plurality of corrugations defining a plurality of fuel channels on a first surface of the interconnect main body facing the first electrochemical cell, and a plurality of oxidant channels on a second surface of the interconnect main body facing the second electrochemical cell. Each of the plurality of fuel channels and the plurality of oxidant channel positioned around the longitudinal channel.