Fuel Cell Anode Manifold Segmentation for Uniform Hydrogen Distribution
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Solution Overview
Problem
Fuel cell stacks experience non-uniform hydrogen distribution during start-up, leading to voltage degradation and increased hydrogen exhaust emissions, which can cause cell reversal and reduce the useful life of the stack.
Innovation Solution
A fuel cell system with an anode supply manifold and an anode exhaust manifold, controlled by valves to ensure uniform hydrogen distribution across the fuel cells, minimizing non-uniformity and hydrogen exhaust during start-up by managing air flow and resistive loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydrogen is supplied sequentially from one end of the fuel cell stack to another during start-up, then the start-up process is simplified, but non-uniform hydrogen distribution occurs leading to cell reversal and voltage degradation
Solution Approach 1:
The fuel cell stack is divided into multiple segments (first plurality and second plurality of fuel cells) with separate anode supply manifolds and anode exhaust manifolds for each segment. This segmentation allows independent control of hydrogen supply to different portions of the stack, enabling uniform hydrogen distribution across all fuel cells during start-up while maintaining operational simplicity through modular valve control.
2Object-affected harmful factors
If a resistive load is placed across the stack to suppress cell voltage during hydrogen-air front passage, then carbon corrosion is reduced, but severe performance degradation occurs due to cell reversal
Solution Approach 1:
Hydrogen is supplied to all anodes simultaneously through the segmented manifold system before the fuel cell stack is fully operational. This preliminary uniform hydrogen distribution prevents the formation of hydrogen-air fronts that would otherwise cause cell reversal, allowing the resistive load to effectively suppress cell voltage and reduce carbon corrosion without triggering performance degradation.
3Device complexity
If hydrogen flows from the wet end to the dry end of the fuel cell stack, then the flow path is simplified, but non-uniform distribution occurs with dry end cells receiving hydrogen later
Solution Approach 1:
Instead of relying on a single linear flow path from wet end to dry end, the system introduces a spatial dimension by creating separate anode supply manifolds that distribute hydrogen to multiple segments of the stack simultaneously. This multi-dimensional distribution approach maintains relatively simple flow paths while achieving uniform hydrogen delivery to all fuel cells regardless of their position in the stack.
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
The solution achieves uniform hydrogen distribution, reducing voltage degradation and hydrogen emissions, thereby extending the life of the fuel cell stack and improving start-up performance.
Implementation Method 1
an anode supply manifold in communication with the anodes of the plurality of fuel cells, the anode supply manifold adapted to deliver a anode supply stream to the plurality of fuel cells
Implementation Method 2
an anode exhaust manifold in communication with the anodes of the plurality of fuel cells, the anode exhaust manifold adapted to receive an anode exhaust stream from the plurality of fuel cells
Implementation Method 3
The electrolyte membrane is sandwiched between the cathode and the anode to form a membrane-electrolyte-assembly (MEA). Hydrogen at the anode is converted to positively-charged hydrogen ions. These ions travel through the electrolyte to the cathode
Implementation Method 4
The cathode and anode typically include a finely divided catalyst, generally platinum, supported on carbon particles and mixed with an ionomer
Data Source
AI summary
A fuel cell system is provided having a fuel cell stack including a plurality of fuel cells. The fuel cell system includes an anode supply manifold in fluid communication with the plurality of fuel cells, the anode supply manifold adapted to deliver a anode supply stream to the plurality of fuel cells; an anode exhaust manifold in fluid communication with the anodes of the plurality of fuel cells, the anode exhaust manifold adapted to receive an anode exhaust stream from the plurality of fuel cells; a first valve in fluid communication with the anode supply manifold; and a second valve in fluid communication with the anode exhaust manifold. A method of starting the fuel cell system is also provided. The fuel cell system and method militates against a non-uniform distribution of the anode supply stream to the anodes of the plurality of fuel cells.