Fuel Cell Flow Control Member for Uniform Distribution
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Solution Overview
Problem
In fuel cell stacks, achieving uniform flow distribution across multiple cassettes is challenging due to high air or fuel mass flow rates and momentum, leading to non-uniform distribution and increased pressure drops when using existing methods like wedges or piercing members, which also result in reduced flow to cassettes further away from the air source.
Innovation Solution
The introduction of flow control members, specifically cathode and anode flow control members, which provide tailored flow restrictions between supply and exhaust chimneys for each fuel cell cassette, allowing for customized flow distribution without significantly increasing pressure drops, and are designed to be non-conductive to prevent electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high mass flow rates and momentum are used to supply fuel and oxidant to fuel cell cassettes, then the supply capacity is improved, but non-uniform flow distribution occurs across multiple cassettes
Solution Approach 1:
The patent applies local quality by providing tailored flow restrictions for each fuel cell cassette based on its specific position in the stack. Flow control members with different restriction characteristics are installed at different locations to compensate for position-dependent flow variations, ensuring each cassette receives appropriate flow rates while maintaining overall high supply capacity
Solution Approach 2:
The patent changes flow parameters by introducing flow control members that modify local flow resistance. By adjusting the flow restriction parameters individually for each cassette, the system transforms the non-uniform high-flow distribution into a uniform distribution pattern that maintains high supply capacity across all cassettes
2Manufacturing precision
If flow control members are added to achieve uniform flow distribution, then flow uniformity is improved, but pressure drop increases
Solution Approach 1:
The patent minimizes overall pressure drop by applying flow restrictions only where needed - specifically at cassettes receiving excessive flow - rather than uniformly across all cassettes. This localized approach achieves flow uniformity while minimizing additional pressure drop in the supply system
Solution Approach 2:
The flow control members act as intermediaries that are strategically positioned between the supply manifold and individual cassettes. These intermediaries provide targeted flow resistance only at specific locations, achieving uniform distribution without creating excessive pressure drop throughout the entire system
3Manufacturing precision
If existing flow control methods like wedges or piercing members are used, then flow distribution is improved, but device complexity and pressure drop increase
Solution Approach 1:
The patent employs simple, easily replaceable flow control members that can be individually adjusted or replaced without affecting the entire system. These simple components achieve complex flow distribution goals while maintaining low system complexity and ease of maintenance
Solution Approach 2:
The patent achieves uniform flow distribution by adjusting flow control parameters rather than redesigning the entire supply system. By modifying local flow resistance parameters through simple flow control members, the system maintains structural simplicity while achieving precise flow distribution
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 solution achieves balanced flow distribution across fuel cell cassettes with a minimal additional pressure drop, ensuring consistent fuel and oxidant delivery to each cassette while maintaining a gas-tight seal and electrical isolation, thereby enhancing the overall efficiency and performance of the fuel cell stack.
Implementation Method 1
A first fuel cell cassette of the fuel cell stack includes a flow control member disposed between the anode supply chimney and the anode exhaust chimney or between the cathode supply chimney and the cathode exhaust chimney such that the flow control member provides a flow restriction different from at least one other of the fuel cell cassettes
Implementation Method 2
A typical fuel cell includes an ion conductive electrolyte layer sandwiched between an anode layer and a cathode layer
Implementation Method 3
Oxygen ions from the air migrate from the cathode layer through the dense electrolyte layer in which it reacts with the hydrogen and CO in the fuel, forming water and CO2 and thereby creating an electrical potential between the anode layer and the cathode layer
Data Source
AI summary
A fuel cell stack is provided with a plurality of fuel cell cassettes where each fuel cell cassette has a fuel cell with an anode and cathode. The fuel cell stack includes an anode supply chimney for supplying fuel to the anode of each fuel cell cassette, an anode return chimney for removing anode exhaust from the anode of each fuel cell cassette, a cathode supply chimney for supplying oxidant to the cathode of each fuel cell cassette, and a cathode return chimney for removing cathode exhaust from the cathode of each fuel cell cassette. A first fuel cell cassette includes a flow control member disposed between the anode supply chimney and the anode return chimney or between the cathode supply chimney and the cathode return chimney such that the flow control member provides a flow restriction different from at least one other fuel cell cassettes.