Vented Bolt Voids in Metal-Supported SOFC Stacks
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Solution Overview
Problem
Intermediate temperature metal supported solid oxide fuel cell stacks experience failures due to hydrogen and ion leakage, leading to combustion and electrical shorts, primarily caused by the diffusion of gases and ions through gaskets into bolt voids, resulting in reduced electrical breakdown voltage and potential explosions.
Innovation Solution
The introduction of vented bolt voids and slotted bolt holes in gaskets allows for the release of diffusing hydrogen and ions into the surrounding airflow, preventing accumulation and subsequent risks of combustion and electrical shorts, thereby enhancing the durability and life expectancy of the fuel cell stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gaskets are used to seal bolt voids in fuel cell stacks, then structural integrity and electrical insulation are improved, but hydrogen and ion leakage accumulate in bolt voids leading to combustion and electrical shorts
Solution Approach 1:
The patent extracts the harmful accumulation of hydrogen and ions from the bolt voids by introducing vented bolt holes that channel these substances away from the bolt voids and into the air manifold, where they can be safely dispersed
Solution Approach 2:
The patent introduces an intermediary venting pathway (vented bolt holes) that mediates between the sealed bolt voids and the air manifold, allowing controlled removal of hydrogen and ions without compromising the structural sealing function of the gaskets
2Stability of the object's composition
If bolt voids are sealed to maintain structural integrity, then compression stability is improved, but electrical breakdown voltage decreases due to ion accumulation
Solution Approach 1:
The patent extracts accumulated ions from the bolt voids through the vented bolt holes, preventing ion buildup that would otherwise reduce electrical breakdown voltage and cause electrical shorts
Solution Approach 2:
The patent converts the previously harmful accumulation of ions and hydrogen in bolt voids into a beneficial controlled flow path through the vented holes, where these substances are channeled into the air manifold and safely dispersed, actually improving electrical reliability
3Reliability
If gaskets prevent gas diffusion, then fuel containment is improved, but hydrogen diffuses through gaskets into bolt voids causing combustion
Solution Approach 1:
The patent introduces vented bolt holes as an intermediary escape path for hydrogen that diffuses through the gaskets, channeling it away from the bolt voids and into the air manifold where it can be safely dispersed without causing combustion
Solution Approach 2:
The patent extracts hydrogen that has diffused through the gaskets by providing a dedicated venting pathway through the vented bolt holes, removing the hydrogen from the bolt voids before it can accumulate to combustion-risk levels
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 venting mechanism effectively disperses hydrogen and ions, minimizing the risk of combustion and electrical shorts, thereby extending the operational life and reliability of the fuel cell stack by ensuring safe gas flow and preventing hydrogen-air mixtures from forming in the bolt voids.
Implementation Method 1
the diffusion of gases and ions through gaskets into bolt voids
Implementation Method 2
The introduction of vented bolt voids and slotted bolt holes in gaskets allows for the release of diffusing hydrogen and ions into the surrounding airflow
Data Source
AI summary
A stack (1) of intermediate temperature, metal-supported, solid oxide fuel cell units (10), each unit comprising a metal support substrate (12), a spacer (22) and an interconnect (30) that each have compression bolt holes (34), fuel inlet port (33), fuel outlet port (32) and air outlet (17) therein, wherein bolt voids (34) are formed by aligning the bolt holes and a further void (17) by aligning the air outlets, and the voids are vented, for example, to the environment or further void to prevent the build-up of fuel, moisture or ions.