Fuel Cell Anode Gas Control During System Stop
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Solution Overview
Problem
In solid oxide fuel cell systems, the oxidative degradation of the anode electrode occurs during system stop due to high oxygen concentrations in the anode discharge passage when the anode gas supply is stopped, leading to potential damage and reduced fuel cell performance.
Innovation Solution
A control method that manages the fuel cell system by continuing cathode gas supply during system stop, using a separate gas supply unit to introduce fuel gas into the anode discharge passage, reducing oxygen concentration and preventing oxidative degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the supply of anode gas is stopped during system stop control, then the cooling process of the fuel cell is enabled, but the oxygen concentration in the anode discharge passage increases causing oxidative degradation of the anode electrode
Solution Approach 1:
A separate gas supply unit is introduced as an intermediary device to supply fuel gas to the anode discharge passage during system stop. This mediator prevents direct contact between high-concentration oxygen and the anode electrode by introducing fuel gas that reduces the oxygen concentration, thereby protecting the anode electrode from oxidative degradation while allowing the cooling process to continue
2Temperature
If cathode gas is continued to be supplied during system stop, then the cooling process is achieved, but oxygen flows into the anode discharge passage increasing oxygen concentration
Solution Approach 1:
The separate gas supply unit acts as an intermediary that introduces fuel gas into the anode discharge passage, creating a protective atmosphere that reduces oxygen concentration. This allows the cathode gas to continue flowing for cooling purposes while the intermediary fuel gas supply prevents excessive oxygen from reaching the anode electrode
Solution Approach 2:
The system changes the chemical composition parameter of the gas in the anode discharge passage by introducing fuel gas through the separate gas supply unit. This parameter change transforms the high-oxygen-concentration environment into a lower-oxygen-concentration environment, preventing oxidative degradation while maintaining the cooling function
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively reduces oxidative degradation of the anode electrode by controlling oxygen concentration in the anode discharge passage, ensuring the fuel cell's integrity and performance during cooling and stop processes.
Implementation Method 1
electric power is generated by an electrical chemical reaction between an anode gas containing, for example, hydrogen and hydrocarbons and a cathode gas containing oxygen
Implementation Method 2
The anode off-gas and the cathode off-gas are combusted by a burner in the joining portion
Data Source
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AI summary
A fuel cell system includes a solid oxide fuel cell configured to receive a supply of an anode gas and a cathode gas to generate electric power. The fuel cell system includes an anode discharge passage through which an anode off-gas discharged from the fuel cell flows, a cathode discharge passage through which a cathode off-gas discharged from the fuel cell flows, a joining portion where the anode discharge passage and the cathode discharge passage join. The fuel cell system further includes a gas supply unit configured to supply a fuel gas using a fuel stored in a fuel tank into the anode discharge passage during a system stop.