Control system for a sealed coolant flow field fuel cell power plant having a water reservoir

摘要

The system (10) controls at least one of a pressure of the reactant streams (16A, 16B) within at least one of an anode flow field (28) and a cathode flow field (36), a flow rate of the reactant streams (16A, 16B) flowing through the anode and/or cathode flow fields (26, 28), a temperature of a coolant fluid passing through a sealed coolant flow field (44), and a flow rate of the coolant fluid; so that water (14) moves from a water reservoir (18A, 18B) into the reactant stream (16A, 16B) whenever power generated by the fuel cell (20) is between about 80% and about 100% of a maximum fuel cell power output, and so that water (14) moves from the reactant stream (16A, 16B) into the water reservoir (18A, 18B) whenever fuel cell power is less than about 75% of the maximum power output.

主权项

1. A control system of a fuel cell power plant configured to generate electrical current from an oxidant reactant stream and a hydrogen-rich fuel reactant stream, the control system comprising:
at least one fuel cell including a membrane electrode assembly having a proton exchange membrane disposed between an anode catalyst surface and an opposed cathode catalyst surface of the assembly, an anode flow field defined in fluid communication with the anode catalyst surface and with a fuel inlet line to direct flow of the hydrogen-rich fuel reactant stream from the fuel inlet line adjacent the anode catalyst surface and out of the anode flow field through an anode exhaust as an anode exhaust stream, a cathode flow field defined in fluid communication with the cathode catalyst surface and with a source of the oxidant to direct flow of the oxidant reactant stream from an oxidant inlet line adjacent the cathode catalyst surface and out of the cathode flow field through a cathode exhaust as a cathode exhaust stream; a sealed coolant flow field secured in thermal exchange with one of the anode flow field and the cathode flow field for directing to direct a coolant fluid from a coolant inlet of a coolant loop, through the coolant flow field and through a coolant loop outlet, the coolant loop configured to control a temperature of the coolant fluid within the coolant flow field; at least one water reservoir secured in fluid communication with at least one of the anode flow field and the cathode flow field and secured in fluid isolation from the sealed coolant flow field, the water reservoir configured to move water from the reservoir and into the reactant stream located in the at least one of the anode and cathode flow fields, and to move water from the reactant stream located in the at least one of the anode and cathode flow fields and into the at least one reservoir; and, a relative-humidity controller secured in communication with the fuel cell and configured to selectively control at least one of a pressure of the reactant streams, a flow rate of the reactant streams, and a temperature of the coolant fluid within the sealed coolant flow field, so that water moves from the water reservoir into the reactant gas streams whenever power generated by the fuel cell is between about eighty percent and about one-hundred percent of a predetermined maximum power output of the fuel cell, and so that water moves from the reactant gas streams into the water reservoir whenever power produced by the fuel cell is less than about seventy-five percent of the predetermined maximum power output of the fuel cell.