Circulation of biphase fuel cell coolant

摘要

Coolant velocity greater than zero everywhere within the coolant channels (78, 85) of fuel cells (38) in a fuel cell stack (37) is assured by providing a flow of biphase fluid in the coolant channels, the flow being created by the outflow of a condenser (59). Positive pressure is applied to the coolant inlet (66) of the coolant channels. Biphase flow from an oxidant exhaust condenser, which may be a vehicle radiator (120), renders the coolant return flow more freeze tolerant. Using biphase flow within the coolant channels eliminates the need for a bubble-clearing liquid pump and reduces liquid inventory and other plumbing; this makes the fuel cell power plant more freeze tolerant.

主权项

1. A fuel cell power plant comprising:
a stack (37) of fuel cells (38), each fuel cell having coolant passageways (78, 85) connected between a coolant inlet (66) and a coolant outlet (68), a fuel reactant gas flow field plate (75) connected between a fuel inlet (42) and a fuel outlet (47), an oxidant reactant gas flow field plate (81) connected between an air inlet (53) and an air outlet (57), at least one of said plates being porous and hydrophilic, and a membrane electrode assembly, including anode and cathode catalysts, disposed between said flow field plates; and a controller (79; characterized by: a condenser (59); said coolant inlet (66a) includes a gas/liquid separator (107/108) having a gas exhaust outlet controlled by said controller; and fluid communication between said air outlet (57), through said condenser, to said coolant inlet (66a).