Glass-Ceramic Fuel Cell Seal for Manifold-Free Crossflow Stacks
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Solution Overview
Problem
Fuel cell stacks face challenges with complex fuel distribution systems and density variations, leading to reduced contact area and performance, as well as issues with fuel starvation and operational efficiency due to the presence of fuel manifolds and internal risers, which complicate manufacturing and require precise metrology.
Innovation Solution
The use of a crossflow fuel cell design without internal fuel manifolds, employing a chromium-iron alloy interconnects with a glass or glass ceramic seal to create a hermetically sealed wall, ensuring uniform fuel distribution and maximizing fuel utilization, while maintaining compatibility with existing materials and reducing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If internal fuel manifolds and risers are used for fuel distribution, then fuel can be delivered to each cell, but the system complexity increases and contact area between components is reduced
Solution Approach 1:
The patent removes internal fuel manifolds and risers from the fuel cell stack, extracting the problematic components that caused complexity and poor contact. Fuel distribution is achieved through external manifolds instead, eliminating the need for internal fuel delivery structures within the stack itself.
Solution Approach 2:
The interconnect plates are designed to serve multiple functions: they act as structural support, provide external fuel distribution channels, and ensure proper contact between cells. This multi-functionality eliminates the need for separate internal fuel distribution systems.
2Ease of operation
If internal risers are used for fuel delivery, then fuel reaches the cells, but manufacturing precision requirements increase and contact area decreases
Solution Approach 1:
Internal risers are completely removed from the design. Fuel delivery is accomplished through external manifolds that connect to the interconnect plates, eliminating the need for precise internal fuel delivery channels and reducing manufacturing precision requirements.
Solution Approach 2:
External manifolds serve as intermediary components that distribute fuel to the stack. These manifolds connect to the interconnect plates, providing a simple and precise fuel delivery mechanism without requiring complex internal structures within the fuel cells themselves.
3Reliability
If glass or glass ceramic seal is used with interconnects, then hermetic sealing is achieved, but thermal stress must be managed
Solution Approach 1:
The patent uses composite sealing structures combining glass or glass ceramic materials with metal interconnects. This composite approach provides hermetic sealing while the glass-ceramic material's thermal properties help manage thermal stress through controlled expansion and contraction characteristics.
Solution Approach 2:
The sealing system is designed to accommodate thermal stress by controlling the thermal expansion parameters of the glass-ceramic seal material to match the metal interconnects. This parameter matching reduces thermal stress during temperature cycling while maintaining hermetic sealing.
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 design enhances fuel cell stack performance by eliminating fuel manifolds, achieving uniform contact and distribution, improving fuel utilization, and reducing thermal stress, thus increasing operational efficiency and longevity.
Implementation Method 1
a fuel impermeable, hermetically sealed wall including a stack of a glass or glass ceramic seal
Implementation Method 2
employing a chromium-iron alloy interconnects with a glass or glass ceramic seal to create a hermetically sealed wall, ensuring uniform fuel distribution and maximizing fuel utilization, while maintaining compatibility with existing materials and reducing thermal stress
Data Source
AI summary
An electrochemical cell stack includes a first interconnect, a second interconnect, an electrochemical cell located between the first interconnect and the second interconnect, and a fuel impermeable, hermetically sealed wall contacting opposing surfaces of the first interconnect and the second interconnect. The fuel impermeable, hermetically sealed wall includes a stack of a glass or glass ceramic seal and a gas impermeable layer. The electrochemical cell is laterally offset from ends of the first interconnect and the second interconnect.