摘要:
A fuel cell having a non-uniform electrical resistivity over the flow area of the cell. Resistance is higher in areas of the cell having locally low levels of hydrogen than in areas having locally high levels of hydrogen. Excess oxygen ion migration and buildup is suppressed in regions having low hydrogen concentration and is correspondingly increased in regions having a surfeit of hydrogen. Destructive oxidation of the anode is suppressed and a greater percentage of the hydrogen passed into the cell is consumed, thereby increasing electric output.
摘要:
In a fuel cell assembly, nickel-based anodes are readily oxidized when exposed to oxygen as may happen through atmospheric invasion of the assembly during cool-down following shutdown of the assembly. Repeated anode oxidation and reduction can be destructive of the anodes, leading to cracking and failure. To prevent such oxygen migration, check valves and oxygen getter devices containing oxygen-scavenging material such as metallic nickel are provided in the reformate passageways leading to and from the anodes. The check valves preferably are closed by gravity. Oxidation of the oxygen-gettering material is readily reversed through reduction by reformate when the assembly is restarted.