Fuel cell stack melting of coolant water during frozen startup
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
H01M-008/04
H01M-008/10
출원번호
US-0361120
(2003-02-06)
발명자
/ 주소
Reiser,Carl A.
Sribnik,Frederick F.
출원인 / 주소
UTC Fuel Cells, LLC
인용정보
피인용 횟수 :
5인용 특허 :
6
초록▼
A PEM fuel cell system (19) has a multifunction oxidant manifold (98) disposed contiguously beneath a fuel cell stack (20), serving as coolant accumulator (28). An electric heater (45) is powered by the fuel cell electrical output (47, 51) during frozen startup. Auxiliary pump (54) and conduits (55,
A PEM fuel cell system (19) has a multifunction oxidant manifold (98) disposed contiguously beneath a fuel cell stack (20), serving as coolant accumulator (28). An electric heater (45) is powered by the fuel cell electrical output (47, 51) during frozen startup. Auxiliary pump (54) and conduits (55, 57, 58) forces water (28) above oxidant pressure in upper coolant manifold (41), into the oxidant flow fields to be warmed before flowing from the oxidant exhaust to the accumulator to melt additional ice. Alternatively, melted coolant is forced by oxidant pressure into coolant channels for heating. Conduit ( 61) conducts coolant from the coolant flow fields to the accumulator. A condensing heat exchanger (65) embedded in accumulator coolant receives oxidant exhaust. A condensing heat exchanger (70) has cold inlet air (75) and warm moist oxidant exhaust (72) on opposite sides, condensing liquid into the accumulator. Melting of coolant may be started by a heater (45) powered by a battery ( 80) or by circulating externally heated (83) glycol.
대표청구항▼
What is claimed is: 1. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels in fluid communication with said accumulato
What is claimed is: 1. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels in fluid communication with said accumulator and with (b) fuel and oxidant reactant gas flow fields, said method comprising: transferring energy derived directly from said fuel cells to the coolant in said accumulator thereby to melt ice in said accumulator, by applying electric power as it is generated by said fuel cell system to a resistance heater disposed in the coolant in said accumulator. 2. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels in fluid communication with said accumulator and with (b) fuel and oxidant reactant gas flow fields, said method comprising: transferring waste heat as it is generated by said fuel cells within said oxidant reactant gas flow fields to the coolant in said accumulator, thereby to melt ice in said accumulator, by heating a portion of coolant in said accumulator to provide water; and pumping said water, under pressure higher than the pressure in said oxidant reactant gas flow fields, into a coolant manifold connected to said coolant flow channels, which manifold is higher than said accumulator, thereby enabling said water to flow front said coolant flow channels into said oxidant reactant gas flow fields and from said oxidant reactant gas flow fields to said accumulator by force of gravity. 3. A method according to claim 2 of starting a fuel cell system in which said coolant flow channels extend between an upper coolant manifold and a lower coolant manifold which is lower than said upper coolant manifold, and wherein said step of pumping further comprises: flowing water into said accumulator from said coolant flow channels through said lower coolant manifold. 4. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels in fluid communication with said accumulator and with (b) fuel and oxidant reactant gas flow fields, said method comprising: transferring waste heat as it is generated by said fuel cells within said oxidant reactant gas flow fields to the coolant in said accumulator, thereby to melt ice in said accumulator, by flowing exhaust of said oxidant reactant gas flow fields through a heat exchanger disposed below coolant level in said accumulator. 5. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels in fluid communication with said accumulator and with (b) fuel and oxidant reactant gas flow fields, said method comprising: transferring energy derived directly from said fuel cells in the form of waste heat as it is generated by said fuel cells within said oxidant reactant gas flow fields to the coolant in said accumulator thereby to melt ice in said accumulator, by flowing inlet oxidant reactant gas from a source through passages in a heat exchanger disposed in a space above and in fluid communication with said accumulator; and flowing exhaust of said oxidant reactant gas flow field through said space, the inlet oxidant reactant gas thereby cooling the heat exchanger and condensing water out of the oxidant reactant gas exhaust, said condensed water thence flowing into said accumulator to melt coolant therein. 6. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels in fluid communication with said accumulator and with (b) fuel and oxidant reactant gas flow fields, in which said coolant flow channels extend between an upper coolant manifold and a lower coolant manifold which is lower than said upper coolant manifold, said method comprising: transferring waste heat as it is generated by said fuel cells within said oxidant reactant gas flow fields to the coolant in said accumulator thereby to melt ice in said accumulator, by heating a portion of coolant in said accumulator to provide water; pumping said water to said upper coolant manifold; and flowing water into said accumulator from said coolant flow channels through said lower coolant manifold. 7. A method according to claim 6 wherein said step of heating comprises: applying electric power generated by said fuel cell system to a resistance heater disposed in thermal communication with the coolant in said accumulator. 8. A method according to claim 6 wherein said step of heating comprises: applying electric power from a battery to a resistance heater disposed in thermal communication with the coolant in said accumulator. 9. A method according to claim 6 wherein said step of heating comprises: flowing a heated solution of antifreeze and water through a heat exchanger in thermal communication with said coolant. 10. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels in fluid communication with said accumulator and with (b) fuel and oxidant reactant gas flow fields, and in which said coolant flow channels extend from a lower inlet manifold to an upper exit manifold, and said oxidant reactant gas flow fields are at a pressure above atmospheric and in fluid communication with said accumulator, said method comprising: transferring waste heat as it is generated by said fuel cells within said oxidant reactant gas flow fields to the coolant in said accumulator thereby to melt ice in said accumulator, by heating a portion of coolant in said accumulator to provide a small amount of melt water; and venting said coolant exit manifold to atmospheric, whereby pressure of said oxidant reactant gas flow fields forces said melt water into said coolant channels so that said melt water is warmed in said stack. 11. A method according to claim 10 further comprising: reducing the pressure in said oxidant reactant gas flow fields so that said warmed melt water flows back into said accumulator thereby melting additional water in said accumulator. 12. A method according to claim 11 further comprising: restoring the pressure in said oxidant reactant gas flow fields so more melt water is forced into said coolant flow channels to be warmed; and reducing the pressure in said oxidant roactant gas flow fields so warmed melt water flows back into said accumulator, thereby melting more water in said accumulator. 13. A method according to claim 10 further comprising: circulating coolant from said coolant exit manifold to said accumulator by means of a pump. 14. A method according to claim 10 wherein said step of heating comprises: applying electric power generated by said fuel cell system to a resistance heater disposed in thermal communication with the coolant in said accumulator. 15. A method according to claim 10 wherein said step of heating comprises: applying electric power from a battery to a resistance heater disposed in thermal communication with the coolant in said accumulator. 16. A method according to claim 10 wherein said step of heating comprises: flowing a heated solution of antifreeze and water through a heat exchanger in thermal communication with said coolant. 17. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels in fluid communication with said accumulator and with (b) fuel and oxidant reactant gas flow fields, said method comprising: applying electric power, as it is generated by said fuel cells, to an electric heater disposed within coolant in said accumulator; melting coolant in said accumulator with said heater; and flowing said melted coolant into said coolant flow channels, thus transferring energy derived directly from said fuel cells to the coolant in said accumulator thereby to melt ice in said accumulator. 18. A method of starting a fuel cell system when at least part of said system is at a temperature below freezing, said fuel cell system having a coolant accumulator and a stack of contiguous PEM fuel cells with (a) coolant flow channels extend between coolant inlet and outlet manifolds in fluid communication with said accumulator and with (b) fuel and oxidant reactant gas flow fields, said method comprising: transferring waste heat as it is generated by said fuel cells within said oxidant reactant gas flow fields to the coolant in said accumulator thereby to melt ice in said accumulator, by melting coolant with a heater in said accumulator; and flowing said melted coolant into said coolant outlet manifold, in reverse through said coolant channels, to said coolant inlet manifold. 19. A method according to claim 17 wherein said step of flowing comprises: flowing said melted coolant from said coolant inlet manifold normally through said coolant channels to said coolant outlet manifold. 20. A fuel cell system, comprising: a fuel cell stack having a plurality of contiguous fuel cells, each including an anode, a cathode and a PEM membrane electrode assembly disposed between said anode and said cathode, each cell having reactant gas flow channels and coolant channels; electric power output connections; a coolant accumulator in fluid communication with said coolant channels; an electric heater disposed in said accumulator; and means for selectively connecting said heater to said electric power output connections within the first few minutes of startup of said fuel cell assembly when at least a portion of said fuel cell assembly is at a temperature below freezing, thereby to melt coolant in said accumulator. 21. A fuel cell system, comprising: a fuel cell stack having a plurality of contiguous fuel cells, each including an anode having at least one fuel flow field, a cathode having at least one oxidant flow field and a PEM membrane electrode assembly disposed between said anode and said cathode, the oxidant gas flow fields of said cells being separated from said coolant channels by a porous medium; means, operable at start-up of said fuel cell system, for concurrently applying oxidant gas at a first pressure to said oxidant gas flow fields and fuel gas at a second pressure to said fuel gas flow fields thereby causing said fuel cell system to produce electric power; a coolant accumulator in fluid communication with said coolant channels, said oxidant flow fields exhausting directly into said accumulator; a heater, operable at start-up of said fuel cell system, disposed in said accumulator; and a pump, operable at start-up of said fuel cell system, receiving water adjacent said heater and applying said water to said coolant channels at a pressure higher than said first pressure thereby forcing water through said porous medium to provide a flow of water into said flow fields and from said flow fields into said accumulator. 22. A fuel cell system, comprising: a fuel cell stack having a plurality of contiguous fuel cells, each including an anode with at least one fuel flow field, a cathode with at least one oxidant flow field and a PEM membrane electrode assembly disposed between said anode and said cathode, each cell having coolant channels; a coolant accumulator receiving coolant from said coolant channels; a condensing heat exchanger in direct fluid communication with the coolant in said accumulator for exhausting condensate directly into said accumulator; and means for flowing oxidant from a source through said oxidant flow fields and to said heat exchanger, thereby transferring waste process heat in (a) oxidant flow exhausting to said heat exchanger directly into (b) said coolant to melt any ice therein. 23. A fuel cell system, comprising: a fuel cell stack having a plurality of contiguous fuel cells, each inducing an anode with at least one fuel flow field, a cathode with at least one oxidant flow field and a PEM membrane electrode assembly disposed between said anode and said cathode, each cell having coolant channels; a coolant accumulator receiving coolant from said coolant channels; a condensing heat exchanger embedded in said accumulator; and means for flowing oxidant from a source to said oxidant flow fields and for flowing oxidant exhaust from said flow fields through said heat exchanger, thereby transferring waste process heat in (a) oxidant flow exhausting to said heat exchanger into (b) said coolant to melt any ice therein. 24. A fuel cell system, comprising: a fuel cell stack having a plurality of contiguous fuel cells, each including an anode with at last one fuel flow field, a cathode with at least one oxidant flow field and a PEM membrane electrode assembly disposed between said anode and said cathode, each cell having coolant channels; a coolant accumulator receiving coolant from said coolant channels; a condensing heat exchanger in fluid communication with the coolant in said accumulator; means for flowing oxidant from a source through a first side of said heat exchanger and thence into said oxidant flow fields; and said oxidant flow fields exhaust to a second side of said heat exchanger, said second side of said heat exchanger being in fluid communication with the coolant in said accumulator, thereby to cause moisture in said oxidant flow field exhaust to condense at said heat exchanger and flow into said accumulator to melt ice therein, thereby transferring waste process heat in (a) oxidant flow exhausting to said heat exchanger into (b) said coolant to melt any ice therein. 25. A fuel cell system, comprising: a fuel cell stack having a plurality of contiguous fuel cells, each including an anode having at least one fuel flow field, a cathode having at least one oxidant flow field and a PEM membrane electrode assembly disposed between said anode and said cathode, each cell having coolant channels separated from said flow fields by a porous medium; means for applying oxidant gas at a first pressure to said oxidant gas flow fields; means for applying fuel gas at a second pressure to said fuel gas flow fields; a coolant accumulator receiving coolant from said coolant channels, said oxidant flow fields exhausting in direct fluid communication with said accumulator; electric power output connections; an electric heater disposed in heat communication with coolant in said accumulator; means for selectively connecting said heater to said electric power output connections within the first few minutes of startup of said fuel cell assembly when at least a portion of said fuel cell assembly is at a temperature below freezing, thereby to melt coolant in said accumulator; a pump receiving water adjacent said heater and applying said water to said coolant channels at a pressure sufficiently higher than said first pressure, to force water to flow through said porous medium and to flow into said oxidant gas flow fields; a condensing heat exchanger in direct fluid communication with the coolant in said accumulator; and means for flowing oxidant from a source through said oxidant flow fields and to said heat exchanger, thereby transferring waste process heat in (a) oxidant flow exhausting to said heat exchanger into (b) said coolant to melt any ice therein. 26. A method of starting a fuel cell system when at least a portion of it is at a temperature below freezing, said fuel cell system including a fuel cell stack having a plurality of contiguous fuel cells, each including an anode having at least one fuel flow field, a cathode having at least one oxidant flow field and a PEM membrane electrode assembly disposed between said anode and said cathode, each cell having coolant channels separated from said flow fields by a porous medium, electric power output connections, a coolant accumulator receiving coolant from said coolant channels, an electric heater disposed in heat communication with coolant in said accumulator, said oxidant flow fields exhausting in direct fluid communication with said accumulator, said method comprising: (a) applying oxidant gas at a first pressure to said oxidant gas flow fields; (b) applying fuel gas at a second pressure to said fuel gas flow fields; (c) selectively connecting said heater to said electric power output connections within the first few minutes of startup of said fuel cell assembly when at least a portion of said fuel cell assembly is at a temperature below freezing, thereby to melt coolant in said accumulator; (d) pumping water adjacent said heater with a pump to said coolant channels at a pressure higher than said first pressure, to force water to flow through said porous medium and to flow into said oxidant flow fields; and flowing oxidant from a source through said oxidant flow fields and to a condensing heat exchanger in direct fluid communication with the coolant in said accumulator, thereby transferring waste process heat in (a) oxidant flow exhausting to said heat exchanger into (b) said coolant to melt ice therein. 27. A fuel cell system having facility to be started when at least part of said system is at a temperature below freezing, comprising: a coolant accumulator; a stack of contiguous PEM fuel cells having (a) coolant flow channels in fluid communication with said accumulator and having (b) fuel and oxidant reactant gas flow fields; a resistance heater disposed in the coolant in said accumulator; and means for applying electric power as it is generated by said fuel cell system to said heater, thus transferring energy derived directly from said fuel cells to the coolant in said accumulator thereby to melt any ice in said accumulator. 28. A fuel cell system having facility to be started when at least part of said system is at a temperature below freezing, comprising a coolant accumulator; a stack of contiguous PEM fuel cells having (a) coolant flow channels in fluid communication with said accumulator and having (b) fuel and oxidant reactant gas flow fields; and means for transferring heat energy derived directly from said fuel cells from within said oxidant flow fields to the coolant in said accumulator thereby to melt any ice in said accumulator, said means comprising: means for heating a portion of coolant in said accumulator to provide water; a coolant manifold connected to said coolant flow channels, said manifold being higher than said accumulator; and means for pumping said water into said coolant manifold under pressure higher than the pressure in said oxidant reactant gas flow fields, thereby enabling said water to flow into said coolant flow channels and from said coolant flow channels into said oxidant reactant gas flow fields and thence into said accumulator by force of gravity and transferring waste heat of said fuel processing to said water which carries said heat to said accumulator. 29. A system according to claim 28 in which: said coolant flow channels extend between upper and lower coolant manifolds; and wherein said means for pumping further comprises: means for flowing water into said accumulator from said coolant flow channels through said lower coolant manifold which is lower than said upper coolant manifold. 30. A fuel cell system having facility to be started when at least part of said system is at a temperature below freezing, comprising: a coolant accumulator; a stack of contiguous PEM fuel cells having (a) coolant flow channels in fluid communication with said accumulator and having (b) fuel and oxidant reactant gas flow fields; and means for transferring heat energy derived directly from said fuel cells from within said oxidant flow fields to the coolant in said accumulator thereby to melt any ice in said accumulator, said means comprising: a heat exchanger disposed below coolant level in said accumulator; and means for flowing exhaust of said oxidant reactant gas flow fields through said heat exchanger. 31. A fuel cell system having facility to be started when at least part of said system is at a temperature below freezing, comprising: a coolant accumulator; a stack of contiguous PEM fuel cells having (a) coolant flow channels in fluid communication with said accumulator and having (b) fuel and oxidant reactant gas flow fields; and means for transferring heat energy derived directly from said fuel cells from within said oxidant flow fields to the coolant in said accumulator thereby to melt any ice in said accumulator, said means comprising: a source of reactant gas; a heat exchanger disposed in a space above and in fluid communication with said accumulator; means for flowing inlet oxidant reactant gas from said source through passages within said heat exchanger; and wherein exhaust of said oxidant reactant gas flow field flows through said space, the inlet oxidant reactant gas thereby cooling the heat exchanger and condensing water out of water vapor in the oxidant reactant gas flow, said condensed water thence flowing into said accumulator to melt coolant therein. 32. A fuel cell system having facility to be started when at least part of said system is at a temperature below freezing, comprising: a coolant accumulator; a stack of contiguous PEM fuel cells having (a) fuel and oxidant reactant gas flow fields and having (b) coolant flow channels in fluid communication with said accumulator and said coolant flow channels extend between upper and lower coolant manifolds; means for transferring heat energy derived directly from said fuel cells from within said oxidant flow fields to the coolant in said accumulator thereby to melt any ice in said accumulator, said means comprising: means for heating a portion of coolant in said accumulator to provide water; means for pumping said water to said upper coolant manifold; and means for flowing water into said accumulator from said coolant flow channels through said lower coolant manifold which is lower than said upper coolant manifold. 33. A system according to claim 32 wherein said means for heating comprises: a resistance heater in thermal communication with the coolant in said accumulator and powered by electric power generated by said fuel cell stack. 34. A system according to claim 32 wherein said means for heating comprises: a resistance heater in thermal communication with the coolant in said accumulator and powered by a battery. 35. A system according to claim 32 wherein said means for heating comprises: a heat exchanger in thermal communication with the coolant in said accumulator and receiving a heated solution of antifreeze and water. 36. A fuel cell system having facility to be started when at least part of said system is at a temperature below freezing, comprising: a coolant accumulator; a stack of contiguous PEM fuel cells having (a) coolant flow channels in fluid communication with said accumulator and having (b) fuel and oxidant reactant gas flow fields; an electric heater disposed within the coolant in said accumulator; means for applying electric power, as it is generated by said fuel cells, to said electric heater; and means for pumping into said stack, coolant melted in said accumulator with said heater, thus transferring energy derived directly from said fuel cells to the coolant in said accumulator thereby to melt any ice in said accumulator. 37. A system according to claim 33 wherein said means for pumping comprises: pumping water in a reverse direction through said coolant channels. 38. A system according to claim 33 wherein said means for pumping comprises: means for pumping water in a normal direction through said coolant channels. 39. A fuel cell power plant comprising: a fuel cull stack assembly including a stack of contiguous PEM fuel cells having (a) coolant flow channels extending between coolant inlet and coolant outlet manifolds and having (b) fuel and oxidant reactant gas flow fields extending between fuel inlets and outlets and oxidant inlets and outlets, respectively; said fuel cell stack assembly including a coolant accumulator disposed immediately beneath and contiguous with said stack, said accumulator being in fluid communication with said coolant outlet manifold and with one of (c) said oxidant inlets and (d) said oxidant outlets. 40. A power plant according to claim 39 further comprising: a radiator external to said fuel cell stack assembly; a coolant pump external to said fuel cell stack assembly and in liquid communication with said radiator; and coolant tubes disposed in said accumulator and in liquid communication with said radiator and coolant pump. 41. A power plant according to claim 39 further comprising: an electric heater disposed in said accumulator. 42. A power plant according to claim 39 further comprising: a restrictor disposed in said accumulator at the inlet to said coolant inlet manifold. 43. A fuel cell power plant comprising: a fuel cell stack assembly including a stack of contiguous fuel cells having (a) coolant flow channels extending between coolant inlet and coolant outlet manifolds and having (b) fuel and oxidant reactant gas flow fields extending between fuel inlets and outlets and oxidant inlets and outlets, respectively; said fuel cell stack assembly including a coolant accumulator disposed immediately beneath and contiguous with said stack, said accumulator being in fluid communication with said coolant outlet manifold and with one of (c) said oxidant inlets and (d) said oxidant outlets; and means for transferring energy derived directly from said fuel cells to the coolant in said accumulator thereby to melt any ice in said accumulator, said means for transferring energy selected from one or more of: (c) an electric heater disposed in thermal communication with said accumulator and means for applying electric power to said electric heater as it is generated by said fuel cells; and (d) means for transferring to coolant in said accumulator waste heat as it is generated by said fuel cells. 44. A fuel cell power plant comprising: a fuel cell stack assembly including a stack of contiguous PEM fuel cells having (a) coolant flow channels extending between coolant inlet and coolant outlet manifolds and having (b) fuel and oxidant reactant gas flow fields extending between fuel inlets and outlets and oxidant inlets and outlets, respectively; said fuel cell stack assembly including a coolant accumulator disposed immediately beneath and contiguous with said stack, said accumulator being in fluid communication with said coolant outlet manifold and with one of (c) said oxidant inlets and (d) said oxidant outlets; an electric heater disposed in said accumulator; and means for selectively connecting said heater to said electric power output connections within the first few minutes of startup of said fuel cell assembly when at least a portion of said fuel cell assembly is at a temperature below freezing, thereby to melt coolant in said accumulator. 45. A fuel cell power plant comprising: a fuel cell stack assembly including a stack of contiguous fuel cells having (a) coolant flow channels extending between coolant inlet and coolant outlet manifolds and having (b) fuel and oxidant reactant gas flow fields extending between fuel inlets and outlets and oxidant inlets and outlets, respectively; said fuel cell stack assembly including a coolant accumulator disposed immediately beneath and contiguous with said stack, said accumulator being in fluid communication with said coolant outlet manifold and with said oxidant outlets; the oxidant gas flow fields of said cells being separated from said coolant channels by a porous medium; means for applying oxidant gas at a first pressure to said fuel gas flow fields; means for applying fuel gas at a second pressure to said oxidant gas flow fields; a heater disposed in said accumulator; and a pump receiving water adjacent said heater and applying said water to said coolant channels at a pressure higher than said first pressure, thereby forcing water through said porous medium into said flow fields. 46. A fuel cell power plant comprising: a fuel cell stack assembly including a stack of contiguous fuel cells having (a) coolant flow channels extending between coolant inlet and coolant outlet manifolds and having (b) fuel and oxidant reactant gas flow fields extending between fuel inlets and outlets and oxidant inlets and outlets, respectively; said fuel cell stack assembly including a coolant accumulator disposed immediately beneath and contiguous with said stack, said accumulator being in fluid communication with said coolant outlet manifold and with one of (c) said oxidant inlets and (d) said oxidant outlets; a condensing heat exchanger in fluid communication with the coolant in said accumulator; and means for flowing oxidant from a source through said oxidant flow fields and to said heat exchanger, thereby transferring waste process heat in (a) oxidant flow exhausting to said heat exchanger into (b) said coolant to melt any ice therein. 47. A fuel cell power plant comprising: a fuel cell stack assembly including a stack of contiguous fuel cells having (a) coolant flow channels extending between coolant inlet and coolant outlet manifolds and having (b) fuel and oxidant reactant gas flow fields extending between fuel inlets and outlets and oxidant inlets and outlets, respectively; said fuel cell stack assembly including a coolant accumulator disposed immediately beneath and contiguous with said stack, said accumulator being in fluid communication with said coolant outlet manifold and with one of (c) said oxidant inlets and (d) said oxidant outlets; the oxidant gas flow fields of said cells being separated from said coolant channels by a porous medium; means for applying oxidant gas at a first pressure to said fuel gas flow fields; means for applying fuel gas at a second pressure to said oxidant gas flow fields; electric power output connections; an electric heater disposed in said accumulator; means far selectively connecting said heater to said electric power output connections within the first few minutes of startup of said fuel cell assembly when at least a portion of said fuel cell assembly is at a temperature below freezing, thereby to melt coolant in said accumulator; a pump receiving water adjacent said heater and applying said water to said coolant channels at a pressure higher than said first pressure, thereby forcing water through said porous medium into said flow fields; a condensing heat exchanger in fluid communication with the coolant in said accumulator; and means for flowing oxidant from a source through said oxidant flow fields and to said heat exchanger, thereby transferring waste process heat in (a) oxidant flow exhausting to said heat exchanger into (b) said coolant to melt any ice therein. 48. A fuel cell power plant comprising: a fuel cell stack assembly including a stack of contiguous fuel cells having (a) coolant flow channels extending between coolant inlet and coolant outlet manifolds and having (b) fuel and oxidant reactant gas flow fields extending between fuel inlets and outlets and oxidant inlets and outlets, respectively; a multifunction oxidant reactant gas manifold in fluid communication with said oxidant reactant gas flow fields and serving as one of (a) an oxidant inlet manifold or (b) an oxidant outlet manifold, said oxidant manifold being beneath and contiguous with said stack, said oxidant manifold in fluid communication with said coolant outlet manifold and serving as a coolant accumulator. 49. A power plant according to claim 48 further comprising: a radiator; a coolant pump in liquid communication with said radiator; and coolant tubes in liquid communication with said radiator and said pump and disposed in said oxidant manifold to serve as a heat exchanger between coolant in said accumulator and external coolant circulated between said radiator and said tubes by said pump. 50. A power plant according to claim 48 further comprising: an electric heater disposed in said oxidant manifold to heat coolant in said accumulator. 51. A power plant according to claim 48 further comprising: a flow restrictor disposed in said oxidant manifold at the inlet to said coolant inlet manifold.
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이 특허에 인용된 특허 (6)
Condit, David A.; Perry, Michael L.; Breault, Richard D., Freeze tolerant fuel cell power plant.
Reiser, Carl A.; Resnick, Gennady; Popovich, Neil A., Initiating operation of an electric vehicle or other load powered by a fuel cell at sub-freezing temperature.
Fletcher Nicholas J.,CAX ; Boehm Gustav A.,DEX ; Pow Eric G.,CAX, Method and apparatus for commencing operation of a fuel cell electric power generation system below the freezing temper.
Reiser, Carl A.; Meyers, Jeremy P.; Johnson, David D.; Evans, Craig E.; Darling, Robert M.; Skiba, Tommy; Balliet, Ryan J., Fuel cells evaporative reactant gas cooling and operational freeze prevention.
Darling, Robert M.; Evans, Craig E.; Reiser, Carl A.; Skiba, Tommy; Balliet, Ryan J., Retaining water in a fuel cell stack for cooling and humidification during frozen startup.
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