Ceramic Gas Conduit for SOFC Stack Electrical Isolation

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Solution Overview

Problem

Conventional high-temperature fuel cell systems face limitations in electrical insulation due to the limited insulating properties of existing coatings, particularly when connecting fuel cell stacks in series, which can lead to short-circuit currents and parasitic currents via pipelines.

Innovation Solution

A gas piping device made of high-temperature-resistant ceramic material, such as aluminum oxide, is used to interrupt electrical conductivity between fuel cell stacks, combined with metallic connections and compensation sections to manage thermal expansion, ensuring effective insulation and serial connection of fuel cell stacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional insulating coatings are used on fuel cell stack components, then the system can maintain electrical insulation, but the insulation performance is limited due to coating technology limitations and layer thickness

Engineering Contradiction:
Improveelectrical insulation performanceVSAvoidcoating technology limitations
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from conventional coatings to ceramic material, fundamentally altering the insulation properties. The ceramic conduit body provides superior electrical insulation without being constrained by coating thickness limitations, directly resolving the contradiction between insulation performance and manufacturing limitations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material construction with the conduit body made of ceramic material for insulation, while connection sections and connecting means are made of metallic materials for electrical connection. This composite approach allows each component to be optimized for its specific function, achieving both superior insulation and ease of assembly.

Inventive Principle:
Principle #40Composite materials

2Strength

If metallic piping sections are used to connect fuel cell stacks, then mechanical strength and thermal resistance are adequate, but electrical conductivity causes short-circuit currents and parasitic currents between stacks

Engineering Contradiction:
Improvemechanical strengthVSAvoidshort-circuit currents
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent segments the piping system into three distinct functional parts: a ceramic conduit body for insulation, and metallic connection sections for electrical connection. This segmentation allows the harmful electrical conductivity to be isolated to only where needed (connection sections), while the majority of the piping (conduit body) provides insulation, preventing short-circuit currents.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ceramic conduit body acts as an intermediary element between metallic piping sections, interrupting electrical conductivity while maintaining mechanical continuity of the gas flow path. This intermediary ceramic component prevents parasitic currents from flowing through the piping system between fuel cell stacks.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If ceramic material is used for the conduit body to provide electrical insulation, then electrical insulation performance improves significantly, but thermal expansion management becomes more challenging

Engineering Contradiction:
Improveelectrical insulationVSAvoidthermal expansion compensation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent explicitly addresses thermal expansion by providing compensation means designed to accommodate the different thermal expansion characteristics of ceramic and metallic materials. The connection sections and connecting means incorporate features that allow for thermal movement, preventing stress buildup while maintaining the electrical insulation benefits of the ceramic conduit body.

Inventive Principle:
Principle #37Thermal expansion

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 ceramic gas piping device provides superior electrical insulation, preventing short-circuit currents and allowing for a denser, more efficient arrangement of fuel cell stacks while withstanding high temperatures and thermal fluctuations.

Implementation Method 1

the conductor body is made of a ceramic material, for electrical insulation of electrical potentials at axial ends of the conductor body

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

the high operating temperatures of the gases, the invention further provides for the first time a ceramic body as an intermediate piece in a gas line

Methodology Applied
Scientific EffectThermal resistance: Thermal Insulation

Implementation Method 3

different thermal expansions of a ceramic of the conduit body and different metals of the connection sections and the connecting means

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4562702B1Gas conduit device for high-temperature fuel cells
Publication Date: 2025.12.24 AVL LIST GMBH
  • EP4562702B1 patent drawingFigure 1~2
  • EP4562702B1 patent drawingFigure 3

AI summary

The present invention relates to a gas conduit device (10) which serves to conduct a high-temperature gas between high-temperature fuel cell stacks (SOFC stacks). According to the invention, the gas conduit device (10) has a conduit body (11), which is made of a ceramic material and serves to electrically isolate electrical potentials at axial ends of the conduit body (11).