Fuel Cell Shutdown Control Using Purge and Voltage Thresholds
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Solution Overview
Problem
Fuel cell systems face issues of catalyzer deterioration due to oxidation and require configurations to prevent dryness of proton conduction films, while also needing simplicity, weight reduction, and space reduction for mobile applications.
Innovation Solution
A method of controlling a fuel cell device by inserting an electrolyte membrane between the fuel and oxidant electrodes, purging supply units when operation ends, measuring voltage, and depressurizing or filling with inert gas when voltage is below a threshold, and short-circuiting electrodes as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If air breathing is performed in a fuel cell system, then power generation is maintained, but catalyzer deterioration occurs and reliability decreases
Solution Approach 1:
The patent applies the inert atmosphere principle by introducing a nitrogen atmosphere into the fuel cell system during operation stopping. This nitrogen environment prevents oxidation of the catalyzer and other components, thereby maintaining reliability and durability while allowing the system to transition between power generation and storage modes without degradation
2Power
If voltage between electrodes is high during air breathing, then power generation efficiency is improved, but electrolyte film and gas diffusion layer deteriorate due to combustion
Solution Approach 1:
The patent uses an inert nitrogen atmosphere to prevent combustion-related deterioration of the electrolyte film and gas diffusion layer. By maintaining a non-oxidizing environment, the system can operate at high voltages during power generation without causing thermal or oxidative damage to these critical components
3Reliability
If humidifiers are added to maintain dryness of proton conduction films, then fuel cell performance is improved, but system complexity, weight, and space increase
Solution Approach 1:
The patent employs the self-service principle where the fuel cell system automatically manages its own humidity balance through controlled air supply and nitrogen atmosphere introduction. The system self-regulates moisture levels in the proton conduction films without requiring external humidifiers, thereby maintaining performance while reducing system complexity and weight
Solution Approach 2:
The inert nitrogen atmosphere serves multiple functions including preventing oxidation and managing humidity. By creating a controlled atmospheric environment, the system maintains appropriate moisture levels in the proton conduction films without needing separate humidification equipment
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
Improves safety and reliability, achieves simplicity, weight reduction, and space reduction in fuel cell systems.
Implementation Method 1
Fuel cells are devices that directly convert chemical energy of fuels into electrical energy by causing fuels such as hydrogen to react with oxidants such as air (oxygen) electrochemically
Implementation Method 2
solid polymer electrolyte fuel cells in which hydrogen ion-exchanged polymer membranes or the like are used in electrolytes
Data Source
AI summary
A method of controlling a fuel cell device includes: a step of purging a hydrogen supply unit of a fuel electrode and purging a gas supply unit of an oxidant electrode when an operation of the fuel cell device ends; a step of measuring a voltage between the fuel electrode and the oxidant electrode and determining whether the voltage is greater than a predetermined threshold; a step of continuing power generation in the fuel cell device when the voltage is greater than the predetermined threshold; and a step of depressurizing the hydrogen supply unit and the gas supply unit when the voltage is equal to or less than the predetermined threshold.