Abstract: In a fuel cell system, a reformer supplies reformate to a fuel cell stack. A portion of the reformate flow is diverted for analysis by a hydrocarbon analysis system. Residual hydrocarbons in the reformate may damage the anodes of the fuel cell stack. Although incompletely-reformed reformate may include a variety of hydrocarbon compounds, the invention simply measures methane as an indicator of the overall performance level of the reformer. A currently preferred embodiment includes a catalytic combustion methane sensor. Combustion air and reformate are delivered in a fixed ratio to the sensor via positive displacement pumps. The system can provide alarm means or optionally a shut-off means to protect a fuel cell stack from elevated levels of hydrocarbons in the reformate stream.

Abstract: A fuel cell stack includes a stack of flow plates, a first gasket that is compatible with a coolant and a second gasket that is incompatible with the coolant. The stack of flow plates includes openings to form a coolant passageway that communicates the coolant and a reactant manifold passageway. The second gasket forms a seal around the reactant manifold passageway between an adjacent pair of the plates. The first gasket forms a seal around the coolant manifold passageway between the adjacent pair of plates. At least one region of a particular plate may be associated with a reactant flow, and this plate may include internal passageways that extend between manifold passageways to communicate a coolant. A seal that is substantially permanent isolates the internal passageways from the region(s) of the fuel cell plate that may be associated with reactant flow(s).

Abstract: In a retractable air supply connection system for air supply lines extending between a blower supply plenum and hot zone components of a solid-oxide fuel cell assembly, each such hot zone component is provided with a socket for receiving a retractable connector. Each connector has first and second concentric expandable bellows connected between the plenum and a nipple element having a central passage and nipple for mating with the socket. The inner bellows is coaxial with the socket element and is connected to an individual supply port in the plenum for the particular hot zone component. The outer bellows is connected to the main blower output. A return spring between the hot zone component and the nipple element urges the nipple element from the socket to disconnect the supply line from the hot zone by collapsing the outer bellows to break the conductive heat path when the blower is inoperative.

Abstract: A fuel cell coolant tank system includes a fuel cell stack including a plurality of fuel cells, a coolant manifold, and a coolant outlet manifold. A coolant expansion tank above the fuel cell stack has an input connected to the coolant inlet manifold of the fuel cell stack and an output connected to the coolant outlet manifold of the fuel cell stack.

Abstract: A fuel cell system includes a fuel cell stack, a manifold and a hinge. The manifold forms a sealed interface to communicate reactants with the stack, and the hinge forms a pivotable connection between the stack and the manifold. The fuel cell system also includes at least one gas/water separator that is disposed in the manifold to collect water from one of the flows.

Abstract: A fuel cell stack includes a stack of flow plates, a first gasket that is compatible with a coolant and a second gasket that is incompatible with the coolant. The stack of flow plates includes openings to form a coolant passageway that communicates the coolant and a reactant manifold passageway. The second gasket forms a seal around the reactant manifold passageway between an adjacent pair of the plates. The first gasket forms a seal around the coolant manifold passageway between the adjacent pair of plates. At least one region of a particular plate may be associated with a reactant flow, and this plate may include internal passageways that extend between manifold passageways to communicate a coolant. A seal that is substantially permanent isolates the internal passageways from the region(s) of the fuel cell plate that may be associated with reactant flow(s).

Abstract: A fuel cell stack includes a stack of flow plates, a first gasket that is compatible with a coolant and a second gasket that is incompatible with the coolant. The stack of flow plates includes openings to form a coolant passageway that communicates the coolant and a reactant manifold passageway. The second gasket forms a seal around the reactant manifold passageway between an adjacent pair of the plates. The first gasket forms a seal around the coolant manifold passageway between the adjacent pair of plates. At least one region of a particular plate may be associated with a reactant flow, and this plate may include internal passageways that extend between manifold passageways to communicate a coolant. A seal that is substantially permanent isolates the internal passageways from the region(s) of the fuel cell plate that may be associated with reactant flow(s).

Abstract: A system includes a stack of fuel cell flow plates and a condenser. The stack of fuel cell flow plates include openings to form an inlet manifold passageway and an outlet manifold passageway to communicate a coolant through the stack. The flow plates are capable of transferring thermal energy to the coolant to cause the coolant to change from a liquid state into a gas state. The condenser changes the coolant from the gas state to the liquid state. At least one conduit of the system is connected to communicate the coolant between the condenser and the inlet and outlet manifold passageways.

Abstract: A system for humidifying reactant gas for a fuel cell includes a supply line for supplying reactant gas to a fuel cell, a mist humidifier for producing liquid droplets in the reactant gas, and an evaporator for evaporating the liquid droplets. The evaporator may use a portion of the heat generated by operation of the fuel cell for evaporating the liquid droplets.

Abstract: The invention relates to an enthalpy recovery fuel cell system. Water leaving the fuel cell in the cathode gas output stream is transferred to the cathode gas input stream. The dew point of the input stream of the cathode gas is about the same as the temperature of the leading edge of the active area of the solid electrolyte, such as a proton exchange membrane. The temperature differential across the fuel cell is about the same as the difference in the dew points of the cathode gas entering the fuel cell and the cathode gas exiting the fuel cell.

Abstract: A fuel cell system includes a fuel cell stack and a pump system. The pump system circulates a coolant through the fuel cell stack. The coolant is substantially electrically non-conductive and has a freezing point substantially below the freezing point of water.

Abstract: The invention relates to a fuel cell system having membranes that are used to humidify reactant gases. The membranes effectively prevent contamination of the reactant gases during humidification. The membranes can be used to purify the reactant gases during humidification.

Abstract: A magnetic bearing rotating structure includes a rotor magnetically supported in a housing by a magnetic bearing. A back-up bearing arrangement is used to resist impact on the rotor, including a fixed bumper bearing for resisting a sudden impact, and an auxiliary bearing for rotatably supporting the rotor while the magnetic bearing resumes operation.