A method and apparatus for operating a solid-oxide fuel cell stack with a mixed ionic/electronic conducting electrolyte

Abstract

The present invention provides methods and apparatus for operating a solid oxide fuel cell stack with a mixed ion / electron conducting electrolyte, the present invention provides for operating an intermediate temperature solid oxide fuel cell stack (10) with a mixed ion / electron conducting electrolyte Methods and apparatus for increasing its efficiency. A desired power output of the solid oxide fuel cell stack (10) is determined, and one or more operating conditions of the solid state fuel cell stack (10) are controlled based on the determined desired power output. The controlled operating condition may be at least one of a temperature of the fuel cell stack and a degree of dilution of fuel delivered to the fuel cell stack.

Description

technical field [0001] The present invention relates to a method and apparatus for operating a solid oxide fuel cell stack to increase its efficiency, in particular by altering one or more operating conditions of the solid oxide fuel cell. Background technique [0002] Solid oxide fuel cells (SOFCs) are a promising device for generating electricity from hydrogen or fossil fuels in a more efficient and environmentally friendly manner than more traditional generation technologies. However, conventional SOFCs operate at very high temperatures (above 900°C), and even recent innovations can only lower this temperature to 700-800°C. Such high operating temperatures cause serious problems with the materials used in the construction of such fuel cell stacks and the associated system stack. Materials that can withstand long-term operation at such temperatures tend to be expensive, or brittle, or both expensive and brittle. Attempts to use lower-cost materials such as ferritic stain...

AI Technical Summary

Problems solved by technology

This causes the electrolyte to develop some electronic conductivity, which results in a short-circuit current flowing inside the fuel cell

This short circuit is observed from the outside as a drop in the battery terminal voltage in an open circuit and results in a decrease in the efficiency of converting the energy in the fuel into electricity

[0006] This property of CGO has led many to reject it as an electrolyte material because they believe that the efficiency loss due to internal short circuits is too severe for practical devices.

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