Patent ID: 6322915
Filing Date: 2001-11-27
Classification: H01M,Y02E

Abstract:
A humidification system for a fuel cell power plant that generates electrical energy from a reducing fluid and a process oxidant stream, the system comprising:a. at least one fuel cell for producing the electrical energy from the reducing fluid and process oxidant stream, the fuel cell including a proton exchange membrane electrolyte between an anode and cathode catalyst, a cathode flow field adjacent the cathode catalyst extending between a cathode inlet and a cathode outlet for directing the process oxidant stream to pass adjacent the cathode catalyst, wherein the proton exchange membrane electrolyte extends between an entry edge of the cathode inlet and the cathode outlet, the cathode catalyst extends from about the cathode outlet to a point between the entry edge of cathode inlet and the cathode outlet, so that a humidification zone within the cathode flow field substantially overlies the portion of the proton exchange membrane electrolyte extending between the entry edge of the cathode inlet and the point between the entry edge of the cathode inlet and cathode outlet to which the cathode catalyst extends;b. a coolant flow field adjacent the cathode flow field including a coolant inlet, a coolant outlet, and coolant distribution means between the coolant inlet and coolant outlet for directing at least some of a coolest portion of a coolant stream within the coolant flow field to flow along an entire length of the cathode inlet to cool the process oxidant stream adjacent the cathode inlet, wherein the entire length of the cathode inlet is about the same as a length axis of the cathode catalyst that passes through a shortest distance across the cathode catalyst perpendicular to a width axis of the cathode catalyst, which width axis is a shortest distance between the cathode flow field and the anode catalyst, and perpendicular to flow of the process oxidant stream through the cathode flow field from the cathode inlet to the cathode outlet; and,c. a pressure control means secured to a coolant line that supplies the coolant stream to the coolant flow field for maintaining a positive pressure differential between the process oxidant stream within the cathode flow field and the coolant stream within the coolant flow field so that the coolant stream within the coolant flow field is at a pressure that is lower than a pressure of the process oxidant stream within the cathode flow field.