Abstract: A fuel cell stack that includes a stack of fuel cells each having a cathode side bipolar plate including parallel cathode gas flow channels. Airflow from a cathode inlet manifold is directed to the flow channels to provide the cathode gas to the fuel cell membrane. The fuel cell stack includes a device positioned within the inlet manifold that selectively blocks a predetermined number of the flow channels for each cell at low load operation to increase the flow rate in the unblocked flow channels, so that the fuel cell stack generates the desired low load output, and the increased flow rate prevents water from accumulating in the unblocked flow channels.

Abstract: A system and method for reducing RH cycling of the membranes in a fuel cell stack. A control algorithm damps a power request signal using a first order filter during low power transients so that the fuel cell stack continues generating power at a higher rate than is requested. The excess power generated by the stack is used to recharge a battery in the fuel cell system. The damped power signal is weighted so that more fuel cell stack power is provided for a low battery state of charge unless stack power is provided for a high battery state of charge.

Abstract: A hybrid fuel cell system that includes a fuel cell stack and a high voltage battery. The fuel cell system also includes a cell voltage controller that controls the average cell voltage of the cells in the fuel cell stack, a damped driver request module that damps a driver power request signal, and a power balancing module. The power balancing module maintains the cell voltage of the cells in the stack within a predetermined range, and uses excess power from the stack beyond what is requested to charge the battery. The power balancing module includes a base load limiter that prevents the cell voltage from going above a predetermined value, unless the battery is at is maximum state of charge.

Abstract: A hybrid fuel cell system that includes a fuel cell stack and a high voltage battery. The fuel cell system also includes a cell voltage controller that controls the average cell voltage of the cells in the fuel cell stack, a damped driver request module that damps a driver power request signal, and a power balancing module. The power balancing module maintains the cell voltage of the cells in the stack within a predetermined range, and uses excess power from the stack beyond what is requested to charge the battery. The power balancing module includes a base load limiter that prevents the cell voltage from going above a predetermined value, unless the battery is at is maximum state of charge.

Abstract: A compressed gas storage tank that has particular application for storing hydrogen for a fuel cell system. The compressed gas tank includes a cylindrical adapter and valve through which the hydrogen is removed from the tank. A low cost generator is positioned in the tank and has a rotating element positioned in a channel extending through the adapter. As hydrogen is removed from the tank, the mass flow of the hydrogen causes the rotating element to rotate which causes the generator to generate electricity. One or more resistive heating element are positioned in the adapter, preferably proximate to tank seals, that receive an electrical current from the generator that heats the resistive heating element and the adapter to increase the temperature of the adapter and the hydrogen being removed from the tank.

Abstract: A pressure tank system including a pressure release valve that releases pressure in the tank if the valve exceeds a predetermined temperature. In order for the pressure release valve to be effective, it must detect heat at all areas of the tank system. The tank system includes a heat conducting device for transferring heat from anywhere on the tank system to the pressure release valve. In one embodiment, the heat conducting device is a heat conducting mesh that is wrapped around and outside of the pressure tank. In another embodiment, the heat conducting device is an aluminum sheet wrapped around the tank. In another embodiment, the heat conducting device includes heat conducting strips that extend along the tank and are connected to the pressure release valve.

Abstract: A compressed gas storage tank that has particular application for storing hydrogen for a fuel cell system. The compressed gas tank includes a cylindrical adapter and valve through which the hydrogen is removed from the tank. A low cost generator is positioned in the tank and has a rotating element positioned in a channel extending through the adapter. As hydrogen is removed from the tank, the mass flow of the hydrogen causes the rotating element to rotate which causes the generator to generate electricity. One or more resistive heating element are positioned in the adapter, preferably proximate to tank seals, that receive an electrical current from the generator that heats the resistive heating element and the adapter to increase the temperature of the adapter and the hydrogen being removed from the tank.

Abstract: A system and method for reducing RH cycling of the membranes in a fuel cell stack. A control algorithm damps a power request signal using a first order filter during low power transients so that the fuel cell stack continues generating power at a higher rate than is requested. The excess power generated by the stack is used to recharge a battery in the fuel cell system. The damped power signal is weighted so that more fuel cell stack power is provided for a low battery state of charge unless stack power is provided for a high battery state of charge.

Abstract: A fuel cell stack that includes a stack of fuel cells each having a cathode side bipolar plate including parallel cathode gas flow channels. Airflow from a cathode inlet manifold is directed to the flow channels to provide the cathode gas to the fuel cell membrane. The fuel cell stack includes a device positioned within the inlet manifold that selectively blocks a predetermined number of the flow channels for each cell at low load operation to increase the flow rate in the unblocked flow channels, so that the fuel cell stack generates the desired low load output, and the increased flow rate prevents water from accumulating in the unblocked flow channels.