Hermetic Dielectric Conduit Assemblies for High Temperature Fuel Cells

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Solution Overview

Problem

High temperature fuel cell systems face challenges with hermetic sealing and thermal expansion issues, leading to potential leaks and electrical conductivity degradation in fuel cell stacks.

Innovation Solution

The development of hermetic dielectric conduit assemblies that incorporate ceramic and metal components with matched coefficients of thermal expansion, coupled with high-temperature braze alloys, to create a sealed gas delivery system that withstands extreme temperatures and thermal cycling, while providing electrical isolation and minimizing stress on fuel cell components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hermetic sealing is implemented at high temperatures, then leakage prevention is improved, but thermal expansion stress increases

Engineering Contradiction:

Improvehermetic sealingVSAvoidthermal expansion stress

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent changes the physical parameters of the sealing system by using a flexible bellows structure that can expand and contract thermally without compromising the hermetic seal. The bellows design allows controlled deformation under thermal stress, maintaining sealing integrity while accommodating expansion forces.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The sealing system combines multiple materials with different thermal expansion properties - the flexible bellows (likely metal), dielectric seals (ceramic or polymer), and gasket materials - to create a composite structure that balances thermal expansion stresses while maintaining hermetic sealing at high temperatures.

Inventive Principle:

Principle #40Composite materials

2Reliability

If electrically conductive interconnects are used, then electrical connectivity is improved, but electrical isolation between fuel and oxidant sides deteriorates

Engineering Contradiction:

Improveelectrical connectivityVSAvoidelectrical isolation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The interconnect structure is segmented into distinct functional zones: electrically conductive sections for current collection and dielectric sections for electrical isolation. This segmentation allows the same component to perform both electrical connectivity and isolation functions by dividing it into specialized segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Dielectric materials serve as intermediary elements within the interconnect structure, positioned between conductive regions to prevent electrical shorting while maintaining structural continuity. These intermediary dielectric sections enable the interconnect to function as both conductor and isolator.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If rigid sealing structures are used, then structural strength is improved, but thermal cycling durability deteriorates

Engineering Contradiction:

Improvestructural strengthVSAvoidthermal cycling durability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The sealing structure transitions from a rigid, fixed configuration to a dynamic, adaptable one. The bellows design provides controlled flexibility that allows the structure to dynamically adjust to thermal expansion and contraction during cycling, preventing stress concentration and fatigue failure while maintaining sealing integrity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs flexible bellows and compliant sealing elements instead of rigid sealing structures. These flexible components can deform elastically under thermal stress, accommodating dimensional changes during thermal cycling without compromising the hermetic seal or structural integrity.

Inventive Principle:

Principle #30Flexible shells and thin films

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 dielectric conduit assemblies effectively maintain hermetic seals and electrical isolation at high temperatures, reducing the risk of leaks and conductivity degradation, thus enhancing the reliability and efficiency of fuel cell stacks.

Implementation Method 1

an inner dielectric tube (702)... an outer dielectric tube (710)... dielectric rings (704)

Methodology Applied

Scientific EffectDielectric: Dielectric

Implementation Method 2

coupled with high-temperature braze alloys, to create a sealed gas delivery system

Methodology Applied

Scientific EffectBrazing: Brazing

Implementation Method 3

incorporate ceramic and metal components with matched coefficients of thermal expansion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10050298B2Hermetic high temperature dielectric conduit assemblies

Publication Date: 2018.08.14 BLOOM ENERGY CORP

AI summary

A conduit assembly for a fuel cell system includes an inner dielectric tube having a first end and a second end, a first metal tube including a first lip coupled to the first end of the inner dielectric tube, a first dielectric ring coupled to the first lip of the first metal tube, a second metal tube including a second lip coupled to the second end of the inner dielectric tube, a second dielectric ring coupled to the second lip of the second metal tube, and an outer dielectric tube having a first end and a second end, coupled to the inner dielectric tube, the first dielectric ring and the second dielectric ring.