摘要:
A cell stack assembly (102) coolant system comprises a coolant exhaust conduit (110) in fluid communication with a coolant exhaust manifold (108) and a coolant pump (112). A coolant inlet conduit (120) enables transportation of the coolant to the coolant inlet manifold. The coolant system further includes a bypass conduit (132) in fluid communication with the coolant exhaust manifold and the coolant inlet manifold, while a bleed valve (130) is in fluid communication with the coolant exhaust conduit and a source of gas. Operation of the bleed valve enables venting of the coolant from the coolant channels, and through a shut down conduit (124). An increased pressure differential between the coolant and reactant gases forces water out of the pores in the electrode substrates (107,109). An ejector (250) prevents air form inhibiting the pump. Pulsed air is blown (238,239,243,245) through the coolant channels to remove more water.
摘要:
A water transport plate assembly that is useful in fuel cells includes at least one hydrophilic article such as a flow field layer. A method of making the hydrophilic article includes establishing a hydrophilicity of the article by including a plurality of graphite particles (112) having a particular physical characteristic that imparts the hydrophilicity to the article. In one disclosed example, the selected graphite particles (112) have a wettability ratio of a hydrophilic surface area to a total surface area that is sufficient to make the article hydrophilic. In a disclosed example, the wettability ratio is more than 0.10. In a disclosed example, the graphite particles are selected based upon a percentage of prismatic surface area of the total surface area.
摘要:
A PEM fuel cell system includes a plurality of PEM fuel cells arranged in a stack having two opposed, outwardly facing end surfaces; pressure plates positioned relative to said end surfaces for securing said PEM fuel cells in said stack; and spacer members between said end surfaces and said pressure plates for thermally insulating said end surfaces from said pressure plates.
摘要:
Recovery of PEM fuel cell performance is achieved by evacuating (61, 62) or by flowing water absorbing gas (46) through, or both, the fuel flow field (12, 13, 19, 20), the air flow field (25, 26, 30, 31), and the water flow field (36, 39), while resistance of the individual cells, or of the fuel cell stack, is measured; the dry out process is continued until the resistance of the cells (or the resistance per cell, measured across the fuel cell stack as a whole), has increased by at least 5 to 1 (preferably 10 to 1) over the normal resistance of the cells. The water absorbing gas may be air (23) or nitrogen (47); it may be at ambient temperature or heated (50).
摘要:
An exemplary method of treating a material such as carbon or graphite to render at least some surfaces of the material hydrophilic includes coating at least a portion of the at least some surfaces with an oxygenated element and controlling a rate of a breakdown of the oxygenated element to leave a corresponding elemental oxide on the surfaces. In one example, the material is treated before being incorporated into an article comprising the material. Another example method includes treating an article comprising the material. Disclosed examples include precipitation or decomposition as the breakdown of the oxygenated element.
摘要:
A fuel cell includes a membrane electrode assembly comprised of a membrane sandwiched between anode and cathode catalyst structures. An anode separator plate and a cathode separator plate are arranged adjacent to the membrane electrode assembly opposite from one another. The anode and cathode separator plates include opposing sides in which one of the opposing sides of the anode and cathode respectively have fuel and oxidant flow fields in communication with the membrane. The anode separator plate is a structure having a first water permeability and is configured to permit passage of water between its opposing sides and with its flow field, and the cathode separator plate comprises a structure having a second water permeability less than the first water permeability of the anode separator plate. In one example, the anode is provided by a porous separator plate, and the cathode is provided by a non-porous, or solid, plate.
摘要:
Water in a fuel cell accumulator is kept above freezing by a hydrogen/oxygen catalytic combustor fed hydrogen through a mechanical thermostatic valve in thermal communication with the container and connected to a hydrogen supply. The system includes an ejector hydrogen/oxygen combustor and a diffusion hydrogen/oxygen combustor for warming a medium within a container such as water in the accumulator of a fuel cell in response to a mechanic hydrostatic valve which conducts hydrogen to a combustor responsive to the temperature of the container.
摘要:
Water (9) in a fuel cell accumulator (10) is kept above freezing by a hydrogen/oxygen catalytic combustor (13) fed hydrogen through a mechanical thermostatic valve (25) in thermal communication (26) with the container (10) or the air nearby, and connected to hydrogen (28), optionally in series with a timer valve (183). The combustor may comprise an ejector (32) having hydrogen through its primary inlet (31) drawing air through a secondary inlet (33), or a diffusion combustor having a catalyst (38), including TEFLON® to permit water generated by combustion to flow by gravity out of the catalyst, spaced from a heating surface (30), and a diffusion control device (40); low partial pressure of oxygen at the catalyst causing diffusion through the device. Combustion vapor condenses on a surface (146) and is led by hydrophilic woven carbon paper (126) and wicking material (133) downwardly, through a disk (140) and plugs (147) either to ambient to a salt canister (190), or to a porous hydrophilic mixer (200) for mixture with antifreeze (206).
摘要:
The medium (9), such as water, of a container (10), such as a fuel cell accumulator, is kept above freezing by a hydrogen/oxygen catalytic combustor (13) fed hydrogen from a source comprising a mechanical thermostatic valve (25) in thermal communication (26) with the container (10) and connected to a hydrogen supply (28). The combustor may comprise an ejector (32) having hydrogen through its primary inlet (31) drawing air through a secondary inlet (33). The combustor may comprise a diffusion combustor having a catalyst (38) spaced from a heating surface (30) and a diffusion control plate (40) low partial pressure of oxygen at the catalyst causing diffusion through the barrier. Water vapor from combustion condenses on a surface (146) and is led by hydrophilic woven carbon paper (126) to wicking material (133), which has smaller pores than the carbon paper, which leads the water downwardly, through a disk (140) and plugs (147) to atmospheric air. The noble metal catalyst mixture includes TEFLON® to permit water generated by combustion to flow by gravity out of the catalyst.
摘要:
An exemplary method of making a hydrophilic article includes controlling a rate of precipitation of titania from a titanate to allow coating at least a selected portion of the article with the titanate before the precipitation is complete.