Abstract: An energy management system controls the temperature of a fuel cell system while a vehicle is not running. The energy management system includes a fuel cell stack, a blower that provides air to the fuel cell stack, a water supply, and a hydrogen supply. A hydrogen supply valve is connected between the hydrogen supply and the fuel cell stack. A heater is connected to an output of the fuel cell stack. A controller controls the hydrogen supply valve and the blower to power the heater to warm the fuel cell stack and the water supply. The controller starts the blower and opens the hydrogen supply valve if heating is necessary and if a tank level signal exceeds a first tank level value. The controller activates a purge, drains water from the water supply, and inhibits vehicle startup if the tank level signal does not exceed a first tank level value.

Abstract: The present invention discloses a fuel cell system that reduces a hydrogen content of anode effluent exhausted by a fuel cell stack without the use of a tail gas combustor. The fuel cell system reduces the hydrogen content in one or more stages to a level suitable for venting to the environment. A first stage reduction is provided by mixing a portion of the cathode effluent with a controlled quantity of the anode effluent in the presence of a catalytic bed. The resulting stream has a reduced hydrogen content which can then be supplied to the cathode inlet side of the fuel cell stack for further hydrogen content reduction. The fuel cell system also provides a storage device to store the anode effluent to minimize pressure fluctuations between the anode and cathode sides of the fuel cell stack during a purging operation.

Abstract: An apparatus and method to produce hydrogen gas a high pressure is disclosed. An electrolyzer is located inside a pressure vessel that is pressurized with high pressure water. The high pressure water is provided to both the anode and cathode sides of the electrolyzer by a pump in the pressure vessel Oxygen produced at the high pressure on the anode side of the electrolyzer is vented directly into the pressure vessel while hydrogen produced at the high pressure on the cathode side is routed to a separator and is deadheaded. The high pressure hydrogen is periodically routed from the separator to a storage tank by a pressure regulator.