SOFC Contact Element Fabrication via Thermo-Mechanical Treatment

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Solution Overview

Problem

Existing contact elements in electrochemical devices like SOFCs and HTEs face challenges in balancing high conductivity, mechanical accommodation, and low manufacturing costs, with gold grids being expensive and ceramic materials lacking effective mechanical accommodation.

Innovation Solution

A method involving a thermo-mechanical treatment process is used to manufacture contact elements, applying a conductive material layer to interconnectors and subjecting the electrochemical device to temperatures between 850° C. and 1200° C. with mechanical stress, enhancing contact surface area and cohesion while maintaining low costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gold grids are used as contact elements, then good electrical contact and corrosion resistance are achieved, but manufacturing cost increases significantly

Engineering Contradiction:

Improveelectrical contact qualityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a composite structure consisting of a metallic interconnector substrate combined with a ceramic contact element layer. This composite material approach allows achieving good electrical contact and corrosion resistance (properties of gold) while using lower-cost materials (metal+c ceramic combination), thereby resolving the contradiction between reliability and manufacturing cost.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If ceramic materials are used as contact elements, then manufacturing cost is reduced, but mechanical accommodation capacity deteriorates

Engineering Contradiction:

Improvemanufacturing costVSAvoidmechanical accommodation capacity

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The composite structure combines a metallic interconnector (providing mechanical flexibility and accommodation) with a ceramic contact element layer (providing electrical conductivity and corrosion resistance). The metallic substrate compensates for the brittleness of ceramic, enabling the ceramic layer to maintain good electrical contact while the metal provides the necessary mechanical accommodation capacity, thus resolving the contradiction between manufacturing cost and adaptability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The ceramic material is applied locally as a coating or layer on the metallic interconnector surface, rather than using bulk ceramic. This allows the ceramic to provide its beneficial electrical and corrosion properties at the contact interface, while the underlying metal provides the mechanical accommodation throughout the structure, resolving the contradiction between cost and mechanical adaptability.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If nickel grids are used at the hydrogen electrode, then satisfactory electrical contact is achieved at low cost, but performance at the oxygen electrode deteriorates

Engineering Contradiction:

Improvemanufacturing costVSAvoidelectrical contact quality at oxygen electrode

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies different materials to different locations: nickel grids are used at the hydrogen electrode (where they provide satisfactory performance), while a ceramic contact element on metallic interconnector is used at the oxygen electrode (where it provides superior electrical contact and corrosion resistance). This localized material differentiation resolves the contradiction by optimizing each electrode interface for its specific requirements.

Inventive Principle:

Principle #3Local quality

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 method reduces contact resistances, improves mechanical accommodation, and provides corrosion protection, outperforming gold grids and ceramic materials in terms of performance and cost, with contact elements exhibiting improved electrical conductivity and mechanical flexibility.

Implementation Method 1

subjecting the electrochemical device to temperatures between 850° C. and 1200° C. with mechanical stress, enhancing contact surface area and cohesion

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

applying a conductive material layer to interconnectors

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS10090549B2Method of fabricating contact elements in an electrochemical device such as SOFC or EHT

Publication Date: 2018.10.02 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

The invention relates to a method of fabricating a contact element in an electrochemical device (9) such as an SOFC or an EHT which comprises the following steps: a) use is made of: at least one cell (8) consisting of an assemblage made up of an electrode to be hydrogenated (5)-electrolyte (4)-electrode to be oxygenated (3); at least one first interconnector (1); and at least one second interconnector (7); b) at least one layer of a conducting material is deposited on the first interconnector (1) and/or the second interconnector (7); c) an electrochemical device (9) is assembled; said method being characterized in that: d) a thermomechanical treatment is carried out on the electrochemical device obtained on completion of step c). The invention also relates to an electrochemical device (9) equipped with at least one contact element (2) obtained according to this fabrication method.