Abstract: A method includes establishing a fuel flow through a fuel cell stack to produce a current. The voltages of the fuel cell stack are scanned to determine the minimum cell voltage. A maximum limit on the current is set based at least in part on the minimum cell voltage.

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 bridge piece for a fuel cell fluid flow plate having a face and a fluid opening for receiving a fluid, at least one flow channel in the face for distributing a fluid in a fuel cell, and a first groove defined within the face, the groove adapted to receive a sealing member, includes a body having a first surface and a second surface, the first surface having at least one channel for fluidly connecting the fluid opening to the at least one flow channel. The second surface has a second groove defined therein. The second groove is adapted to receive the sealing member.

Abstract: An assembly includes a fuel cell stack, a circuit board, an elastomeric connector and a frame. The elastomeric connector contacts the stack to provide cell voltages of the stack to the circuit board. The frame holds the circuit board, positions the elastomeric connector between the fuel cell stack and the circuit board and provides the appropriate compression of the connector.

Abstract: A hydration system for a fuel cell includes a fluid flow plate having an inlet fluid opening for receiving a hydration fluid, a plurality of reactant flow channels defined in the fluid flow plate, at least one land interposed between the flow channels, and at least one hole defined in and extending through the land. The hole may be fluidly connected to the inlet fluid opening, thereby allowing a portion of the fluid to aid in hydration of a membrane of the fuel cell. A hydration channel also formed in the land may extend from an outlet of the hole to further aid membrane hydration.

Abstract: An assembly includes a receptacle and a sensor body. The receptacle includes an orifice for receiving the sensor body. At least one tab is located on the receptacle or sensor body to engage a feature such as a notch on the other. The sensor body is adapted to be inserted into the orifice. At least one prominence may be included on the receptacle or sensor body to lift the tab(s) out of the feature to release the sensor body from the receptacle when the sensor body is rotated with respect to the receptacle.

Abstract: A fuel cell system includes a fuel cell stack, an inverter, a reformer and a circuit. The fuel cell stack is adapted to produce heat in response to a fuel flow, and the inverter is coupled to the fuel cell stack and is adapted to use electrical energy produced by the fuel cell stack to furnish electrical power that is received by a power grid. The reformer is adapted to produce the fuel flow, and the circuit is adapted to interact with the reformer to produce an approximate predetermined amount of heat. The circuit also determines cell voltages of the fuel cell stack, selects the minimum cell voltage, and interacts with the inverter to regulate the amount of the electrical power that is furnished by the inverter based on the selected voltage.

Abstract: A fuel cell stack assembly includes a stack of fuel cell flow plates that include fluid passageways; pipes to communicate fluids with the fluid passageways; an end plate; and a dielectric manifold. The end plate supports a compressive load to compress the stack, and the end plate includes openings. The manifold is located between the end plate and the stack to communicate the fluids between the pipes and the fluid passageways. The manifold at least partially extends through the openings in the end plate to form a sealed connection between the manifold and the pipes.

Abstract: A fuel cell system includes a fuel cell stack, which during operation generates electrical energy by reacting a first stream of reactant gas and a second stream of reactant gas. The fuel cell stack also produces a fuel cell exhaust stream. An oxidizer unit is positioned to receive the fuel cell exhaust stream and oxidize at least a part of the fuel cell exhaust stream during operation, to produce an oxidizer exhaust stream. A heat recovery system is positioned to receive the oxidizer exhaust stream. The heat recovery system transfers at least some heat from the oxidizer exhaust stream to an input stream to generate a heated stream of water. In some embodiments, a temperature sensor is positioned to sense the temperature of the heated input stream. A control system maintains the heated stream of water at a target temperature based on the sensed temperature by controlling the amount of the heat from the oxidizer exhaust stream that is transferred to the input stream.

Abstract: A fuel cell plate module includes fuel cell composite plates, a pin and a mechanism to hold the pin in place. The plates are arranged in a stack and include a first set of holes, and the pin extends at least partially through the first set of holes to align the plates. For example, a radial extension may extend from a shaft of the pin to secure the pin between an adjacent pair of the plates to hold the pin in place.

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 flow plate gasket that is usable with a first fuel cell plate and a second fuel cell plate includes a material that is adapted to form a seal between the first and second fuel cell plates. The material includes at least two spaced ridges to contact the first fuel cell plate when the gasket is compressed between the first and second fuel cell plates.

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 in the simplest form is a method and apparatus for reliably protecting against island situations with one or multiple power sources connected to an electric distribution grid. The method and apparatus detects variations in the voltage and frequency of the grid. An observed change in grid voltage causes a change in output power that is sufficient to cause an even larger change in grid voltage when the utility AC power source is disconnected. An observed change in grid frequency causes a change in phase or reactive output power that is sufficient to cause an even larger change in grid frequency. If several shifts in voltage or frequency happen in the same direction, the response to the change is increased in an accelerating manner.

Abstract: A fuel cell stack may be enclosed within a plastic membrane. In one embodiment of the invention, a stack may be enclosed within a heat shrinkable membrane and the membrane caused to shrink about the stack. In this way, any leakage of fluids from the stack may be prevented or retarded by the membrane. A variety of different membranes may be utilized including composite membranes made up of barrier film and heat shrinkable puncture resistant film or bubble wrap covered by shrink wrap film. Any openings formed in the enclosure may be closed using plastic tape or heat sealing techniques. A leak detector may be provided within the enclosure for detecting leaks including gas leaks from within the stack.

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: A system includes a divider network, a memory and a circuit. The divider network is adapted to be coupled to fuel cells of a fuel cell stack and provide pairs of signals. Each pair of signals is associated with a different fuel cell and indicates a terminal voltage of the associated cell and another voltage common to the pair of signals. The memory stores indications of different common mode gains, and each common mode gain indication is associated with a different one of the pairs of signals. The circuit is coupled to the memory and adapted to generate an indication of the terminal voltage from each pair based on the associated common mode gain indication.

Abstract: A carbon monoxide filter layer that can be used, for example, in an electrode unit, a fuel cell, and/or a fuel cell stack is disclosed.

Abstract: A fluid flow plate for a fuel cell is provided with hydration channels along the reactant channel lands of the plate. Water is injected into a gas diffusion layer facing the hydration channels in order to promote hydration of the fuel cell membrane.

Abstract: The invention relates to a fuel cell system. The system has one operational state in which a fuel gas supply is connected to the anode flow field plates along a flow path. The system also has a different operational state in which the anode flow field plates are disconnected from the fuel gas supply and connected to an oxidant gas supply along a flow path. The fuel cell system can use a valve and a control system to switch the operational state of the system.