Abstract: A fuel cell system includes fuel cell stacks electrically connected in parallel and supplying a gross current to a load. A controller determines the gross load current, and produces a desired current through the load by adjusting, based on the gross load current, at least one parameter affecting at least one of the inputs to and outputs from the system. This system allows a stack design and its voltage output to be kept constant while stacks are added for increased power.

Abstract: A technique for heating a fuel cell stack at stack start-up that includes using the vehicle motor drive system to generate waste heat independent from providing traction. Particularly, at fuel cell stack start-up, the electric traction inverter associated with the traction motor that drives the vehicle is controlled so that command signals provided by an inverter to a traction motor do not provide motor torque, but dissipates power into the motor windings and/or motor structure as waste heat. Thus, the output power generated by the fuel cell stack can be made high enough to quickly heat the fuel cell stack through inefficiencies in the stack operation, without providing driving torque. Additionally, the electric traction inverter can be operated so that waste heat is generated within the semiconductor power switches in the inverter.

Abstract: A fuel cell system that includes a fuel cell stack providing high voltage power. A tap is electrically coupled to the positive end of the stack to provide a positive voltage output terminal of the fuel cell stack, and a tap is electrically coupled to the negative end of the stack to provide a negative output terminal of the fuel cell stack. A low voltage tap is electrically coupled to one or more intermediate bipolar plates of the stack to provide low voltage power. Several intermediate taps can be electrically coupled to the bipolar plates, where a center intermediate tap is designated a reference potential tap. A switching network switches the several voltage potentials to provide an AC signal.

Abstract: A fuel cell distributed generation system that employs a load following control algorithm that provides the desired output power from a fuel cell on demand. The system includes a current sensor that measures the current drawn from the fuel cell available to satisfy the application load demands. A fuel cell controller receives the measured current and provides a command signal to the fuel cell to increase or decrease its power generation based on the demand. The controller also defines a maximum current that the system can draw from the fuel cell based on its fuel input. The system may include a battery current sensor that measures battery current to insure that the system battery is not being drained. Also, the system may include a battery voltage sensor that monitors battery voltage drift.

Abstract: A fuel cell has a hydrogen flow path adapted to pass hydrogen into communication with an anode catalyst of an MEA. A coolant flow path is adapted to pass coolant through the fuel cell to cool the fuel cell. An enclosure encompasses at least a portion of the hydrogen flow path, the coolant flow path, or both. A hydrogen vent is adapted to vent hydrogen from the enclosure without reliance upon any electrical device. The hydrogen vent can prevent a frame front from passing into the enclosure and can be made of a porous material such as cellulose, plastic (for example, a foamed plastic) or metal (for example a sintered metal). A method of manufacturing a fuel cell includes passively venting hydrogen to maintain a hydrogen concentration level within the enclosure below about 4 percent. Additional enclosures with hydrogen vents may also be provided.

Abstract: A fuel cell system includes fuel cell stacks electrically connected in parallel and supplying a gross current to a load. A controller determines the gross load current, and produces a desired current through the load by adjusting, based on the gross load current, at least one parameter affecting at least one of the inputs to and outputs from the system. This system allows a stack design and its voltage output to be kept constant while stacks are added for increased power.

Abstract: A method of addressing one MEA failure mode by controlling MEA catalyst layer overlap, and the apparatus formed thereby is disclosed. The present invention addresses a feature of membrane electrode assembly (MEA) architecture that is associated with field failures due to the loss of ionomer from the edges of the electrolyte. To address ionomer degradation, the present invention provides a MEA design in which the cathode catalyst edges are closer than the anode catalyst edges to the edges of the electrolyte.

Abstract: A control system (20) for controlling the state of charge in an energy storage device (28) by manipulating the voltage of a fuel cell (24) through dynamic system modeling of predetermined parameters (21) for the fuel cell (24) as well as the energy storage device (28). According to the method (100) of the present invention, manipulation (108) of predetermined parameters related to the fuel cell and the energy storage device control the energy storage device to a desired state of charge or divides the load current between the two devices.

Abstract: A control system (20) for controlling the state of charge in an energy storage device (28) by manipulating the voltage of a fuel cell (24) through dynamic system modeling of predetermined parameters (21) for the fuel cell (24) as well as the energy storage device (28). According to the method (100) of the present invention, manipulation (108) of predetermined parameters related to the fuel cell and the energy storage device control the energy storage device to a desired state of charge or divides the load current between the two devices.