초록 ▼

The invention is a reversible fuel cell power plant (10). A reactant switch-over assembly (48) is secured between a reducing fluid fuel source (30), an oxygen containing oxidant source (24), and first and second flow fields (20) (22) of a fuel cell (12). The switch-over assembly (48) first directs a

The invention is a reversible fuel cell power plant (10). A reactant switch-over assembly (48) is secured between a reducing fluid fuel source (30), an oxygen containing oxidant source (24), and first and second flow fields (20) (22) of a fuel cell (12). The switch-over assembly (48) first directs a reducing fluid fuel stream to flow into the first flow field (20) while it simultaneously directs the oxygen containing oxidant stream to flow into the second flow field (22). Then, after a first half of a useful life span of the fuel cell (12) but before a final one quarter of the useful life span, the switch-over assembly (48) directs the reducing fluid fuel stream to flow into the second flow field (22) while it simultaneously directs the oxygen containing oxidant stream to flow into the first flow field (20).

대표청구항 ▼

1. A method of operating a reversible fuel cell power plant (10) for generating electrical current from hydrogen containing reducing fluid and oxygen containing oxidant reactant streams, the reversible fuel cell power plant (10) including at least one fuel cell (12) having a first electrode (14) and

1. A method of operating a reversible fuel cell power plant (10) for generating electrical current from hydrogen containing reducing fluid and oxygen containing oxidant reactant streams, the reversible fuel cell power plant (10) including at least one fuel cell (12) having a first electrode (14) and a second electrode (16) secured to opposed surfaces of an electrolyte (18), having a first flow field (20) for directing a reactant stream to pass adjacent to the first electrode (14), and having a second flow field (22) for directing a reactant stream to flow adjacent to the second electrode (16) the method comprising the steps of:a. directing the reducing fluid fuel stream to flow into the first flow field (20) of the fuel cell (12), while simultaneously directing the oxygen containing oxidant stream to flow into the second flow field (22) of the fuel cell (12); and, b. then, directing the reducing fluid fuel stream to flow into the second flow field (22) of the fuel cell (12) while simultaneously directing the oxygen containing oxidant stream to flow into the first flow field (20) of the fuel cell (12). 2. The method of operating a reversible fuel cell power plant (10) of claim 1, comprising the further step of directing a coolant stream to flow from a coolant inlet (118) to a coolant outlet (120) of a coolant flow field (122) secured adjacent to the fuel cell (12) so that some of a coolest portion the coolant stream flows from the coolant inlet (118) over a first flow field inlet (98) and outlet (100), and some of the coolest portion of the coolant stream flows from the coolant inlet (118) over a second flow field inlet (108) and outlet (110), wherein the first flow field inlet (98) and outlet (100) direct a reactant stream into, through and out of the first flow field (106), and the second flow field inlet (108) and outlet (110) direct a reactant stream into, through and out of the second flow field (114).3. The method of operating a reversible fuel cell power plant (10) of claim 1, comprising the further step of, prior to the step of directing the reducing fluid fuel stream to flow into the first flow field (20) while simultaneously directing the oxygen containing oxidant stream to flow into the second flow field (22), measuring a useful life span of the fuel cell (12) without a reactant switch-over, then, directing the reducing fluid fuel stream to flow into the first flow field (20) while simultaneously directing the oxygen containing oxidant stream to flow into the second flow field (22), then after one-half of the measured useful life span of the fuel cell (12) but prior to a final one-quarter of the measured useful life span of the fuel cell (12), directing the reducing fluid fuel stream to flow into the second flow field (22) while simultaneously directing the oxygen containing oxidant stream to flow into the first flow field (20).4. A reversible fuel cell power plant (10) for generating electrical current from hydrogen containing reducing fluid fuel and oxygen containing oxidant reactant streams, the power plant comprising:a. at least one fuel cell (12) having a first electrode (14) and a second electrode (16) secured to opposed surfaces of an electrolyte (18), having a first flow field (20) for directing a reactant stream to pass adjacent to the first electrode (14), and having a second flow field (22) for directing a reactant stream to flow adjacent to the second electrode (16); and, b. a switch-over assembly means (48) secured in fluid communication between a reducing fluid fuel source (30), an oxygen containing oxidant source (24), and the first and second flow fields (20) (22), the switch-over assembly means (48) being secured for alternating between a first position wherein the switch-over assembly means (48) directs the reducing fluid fuel stream to flow into the first flow field (20) and directs the oxygen containing oxidant stream to flow into the second flow field (22), and a second position wherein the switch-over assembly means (48) directs the reducing fluid fuel stream to flow into the second flow field (22) and directs the oxygen containing oxidant stream to flow into the first flow field (20). 5. The reversible fuel cell power plant of claim 4, wherein the first electrode (14) includes a first catalyst (66) that is virtually identical to a second catalyst (68) of the second electrode (16).6. The reversible fuel cell power plant of claim 5 wherein the first flow field (20) is virtually identical to the second flow field (22).7. The reversible fuel cell power plant of claim 4, further comprising a coolant flow field (122) secured adjacent the fuel cell (96), the coolant flow field (122) including a coolant inlet (118), a coolant outlet (120) and coolant distribution means between the coolant inlet (118) and coolant outlet (120) for directing flow of a coolant stream between the coolant inlet (118) and coolant outlet (120), the coolant distribution means including a split path coolant distribution channel (128) that directs some of a coolest portion of the coolant stream within the coolant flow field (122) to flow from the coolant inlet (118) over a first flow field inlet (98) and outlet (100), and that directs some of the coolest portion of the coolant stream to flow from the coolant inlet (118) over a second flow field inlet (108) and outlet (110), wherein the first flow field inlet (98) and outlet (100) direct a reactant stream into, through and out of the first flow field (106), and the second flow field inlet (108) and outlet (110) direct a reactant stream into, through and out of the second flow field (114).8. The reversible fuel cell power plant 10) of claim 4, wherein the first flow field inlet (98) and outlet (100) are defined at a first edge (136) of the fuel cell (96) and the second flow field inlet (108) and outlet (110) are defined at a second edge (138) of the fuel cell (96), and the first edge (136) and second edge (138) contact each other to define a corner (140) so that the first flow field (106) and second flow field (114) are non-circular.9. The reversible fuel cell power plant (10) of claim 4, wherein a first flow field (106) inlet (98) is virtually identical to a second flow field (114) inlet (108) and a first flow field (106) outlet (100) is virtually identical to a second flow field (114) outlet (110).10. The reversible fuel cell power plant (10) of claim 4, wherein the electrolyte (18) is a proton exchange membrane electrolyte.