INITIATING OPERATION OF A FUEL CELL POWERED LOAD AT SUB/FREEZING TEMPERATURE

摘要

A vehicle (150) includes a fuel cell stack (151) started when the stack is below freezing, by connection (158) to the vehicle propulsion system (159) within a few seconds of starting the flow of fuel (179) and oxidant (173), or when open circuit voltage (155, 156) is detected. The fuel is in excess of stochiometry requirement and the oxidant is in excess of at least twice stochiometric requirement, either may be at about atmospheric pressure or at 4kPa (0.6 psi) or more above the pressure of any water in said water passages, and either may be below freezing. Water transport plates (84, 86, 88, 89) have water passages connected to a water circulation loop (170) including a reservoir (164) having an auxiliary heater (161) connected (160) to the stack. Warming of cell stack materials and ice in the water transport plates, heat of fusion of melting ice, warming of melted water, and evaporative cooling of water melted in the water transport plates keep the fuel cell cool until liquid coolant can be circulated.