Fuel Cell Pressure Control Using Relative and Absolute Targets
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Solution Overview
Problem
Conventional fuel cell systems face efficiency issues due to fluctuations in ambient pressure, requiring complex adjustments to the pressure regulator and increasing power consumption of the compressor at high altitudes.
Innovation Solution
A fuel cell system with a control device that sets oxygen-containing gas operating pressure targets relative to atmospheric pressure and fuel gas operating pressure targets using absolute pressure, allowing for efficient power generation without needing to increase the compression ratio at high altitudes, thereby maintaining compressor efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compression ratio is increased to maintain power generation efficiency at high altitudes, then the fuel cell power generation efficiency is improved, but the compressor efficiency deteriorates
Solution Approach 1:
The invention changes the pressure reference parameter from absolute pressure to relative pressure (gauge pressure). By setting the cathode operating pressure target as relative pressure and the anode operating pressure target as absolute pressure, the system adapts to ambient pressure changes without increasing compression ratio, thereby maintaining both fuel cell efficiency and compressor efficiency across different altitudes.
2Reliability
If a pressure regulator is provided and its valve position is adjusted according to atmospheric pressure fluctuations, then the outlet pressure of the compressor can be maintained at a constant level, but the system complexity increases
Solution Approach 1:
The invention changes the pressure control parameter from absolute pressure to relative pressure for the cathode side. This parameter change eliminates the need for a pressure regulator valve and its complex control system, while still maintaining stable outlet pressure through the natural adaptation of the compressor to ambient pressure changes.
3Stress or pressure
If the compression ratio is increased at high altitudes, then the oxygen supply pressure to the cathode is sufficient, but the power consumption of the compressor increases
Solution Approach 1:
The invention changes the pressure reference from absolute to relative pressure, allowing the system to maintain adequate oxygen supply pressure without increasing the compression ratio. This parameter change enables the compressor to operate at lower power consumption while still meeting the oxygen supply requirements at high altitudes.
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 simplifies the system structure and operation, improving overall power generation efficiency and reducing power consumption of the compressor, while preventing damage to the fuel cell components by managing differential pressures effectively.
Implementation Method 1
a fuel cell, which is operated to provide power generation by consuming a fuel gas supplied to an anode and an oxygen-containing gas supplied to a cathode
Implementation Method 2
The hydrogen ions move toward the cathode through a suitably humidified electrolyte membrane
Implementation Method 3
A catalyst included in the anode induces a chemical reaction in the fuel gas, in order to split hydrogen molecules into hydrogen ions and electrons
Data Source
AI summary
A fuel cell system includes a control device for setting an oxygen-containing gas operating pressure target value on the cathode side using a relative pressure relative to atmospheric pressure, setting a fuel gas operating pressure target value on the anode side using an absolute pressure, and controlling a power generation current of the fuel cell using as command values the relative pressure and the absolute pressure. The control device controls operation of the entire fuel cell system.