Fuel Cell Stack Control via Open-Circuit Decay Time
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Solution Overview
Problem
Fuel cell stacks suffer from deterioration over time, leading to reduced performance and efficiency, which is typically addressed by costly replacement or repair, requiring time-consuming disassembly and assembly.
Innovation Solution
An apparatus and method that adjust the stoichiometric ratio of air and operating temperature of the fuel cell stack based on open-circuit decay time (ODT) to improve performance, using a map storage system, sensors, and a fuel cell controller to detect and adjust these parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the fuel cell stack operates for extended periods, then power generation experience accumulates, but performance deteriorates due to membrane degradation
Solution Approach 1:
The patent changes operating parameters (air stoichiometric ratio and temperature) based on the measured ODT value to compensate for membrane degradation. By adjusting these parameters dynamically, the system maintains optimal performance despite extended operation and membrane aging.
Solution Approach 2:
The system implements a feedback mechanism where ODT is continuously measured and used to adjust operating parameters. The controller monitors ODT and automatically modifies air stoichiometric ratio and temperature to maintain performance, creating a closed-loop control system that compensates for degradation.
2Reliability
If conventional repair or replacement methods are used, then performance is restored, but time and cost increase due to disassembly and assembly
Solution Approach 1:
The system performs self-diagnosis and self-adjustment by measuring ODT and automatically modifying operating parameters to compensate for degradation. This eliminates the need for manual disassembly, inspection, and repair operations, allowing the system to maintain itself during normal operation.
Solution Approach 2:
Instead of physical repair or replacement, the system restores performance by changing operating parameters (air stoichiometric ratio and temperature) based on ODT measurements, providing a non-invasive method to compensate for membrane degradation.
3Reliability
If air stoichiometric ratio is increased and temperature is reduced, then performance is improved, but energy consumption increases
Solution Approach 1:
The system applies parameter adjustments partially and only when necessary based on ODT measurements. Rather than continuously operating at suboptimal parameters, the system maintains normal operation and only adjusts air stoichiometric ratio and temperature when degradation is detected, minimizing energy waste while providing sufficient compensation.
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
This approach enhances fuel cell stack performance by increasing air stoichiometric ratio and reducing operating temperature, thereby improving fuel efficiency and extending the life of the fuel cell stack without the need for replacement.
Implementation Method 1
A fuel cell is a device that produces electricity by converting chemical energy from a fuel into electrical energy through an electrochemical reaction within a fuel cell stack
Implementation Method 2
a solid polymer electrolyte membrane through which hydrogen ions move
Implementation Method 3
gas diffusion layers (GDLs) serving to uniformly distribute reactant gases
Data Source
AI summary
An apparatus and a method for controlling a fuel cell stack are provided to improve the performance (output) of the fuel cell stack that has suffered from deterioration. The performance is improved by adjusting a stoichiometric ratio (SR) of air supplied to the fuel cell stack and an operating temperature of the fuel cell stack based on the basis of an open-circuit decay time (ODT) indicating a time taken for a cell voltage to be reduced from a reference voltage to a threshold voltage when the supply of air to the fuel cell stack is cut off.