Interconnect End Plate Recesses for SOFC Seal Stress Relief

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional solid oxide fuel cell stacks face issues with compressive stress accumulation and corrosion due to the protrusion of ring seals from interconnect end plates, leading to potential fuel cell damage and increased manufacturing costs.

Innovation Solution

The use of interconnect end plates with recessed ring seal regions, where the protective layer is removed from the ring seal areas to prevent chemical reactions and reduce compressive stress, combined with the option of shims between the end plate and fuel manifold to redistribute pressure evenly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ring seals protrude from interconnect end plates, then sealing function is improved, but compressive stress accumulates and corrosion occurs

Engineering Contradiction:

Improvesealing functionVSAvoidcompressive stress and corrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The interconnect end plate features a recessed ring seal region that creates a localized depression where the glass ring seal sits. This local geometric modification allows the seal to protrude into the recess rather than from the surface, concentrating the sealing function in a specific area while preventing compressive stress accumulation and corrosion on the outer surface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of having the ring seal protrude outward from the interconnect end plate surface, the design inverts this arrangement by creating a recessed region where the seal sits below the outer surface. This inversion maintains the sealing function while eliminating the harmful effects of outward protrusion.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If protective layer is removed from ring seal regions, then corrosion is prevented, but manufacturing complexity increases

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The interconnect end plate is manufactured with distinct segmented regions: a protective layer covers most of the surface, while the ring seal region is specifically excluded from the protective layer during manufacturing. This segmentation allows differential treatment of areas - the protective layer prevents corrosion on the outer surface while the recessed ring seal region remains exposed for proper sealing function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protective layer is applied in advance during manufacturing, but the ring seal region is pre-defined as an excluded area through the recessed geometry design. This preliminary action ensures that the protective layer does not interfere with the sealing function while providing corrosion protection elsewhere, simplifying the overall manufacturing approach.

Inventive Principle:

Principle #10Preliminary action

3Stress or pressure

If shims are added between end plate and fuel manifold, then pressure distribution is improved, but device complexity increases

Engineering Contradiction:

Improvepressure distributionVSAvoidstack assembly

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

A shim is introduced as an intermediary component between the interconnect end plate and the fuel manifold. This thin intermediate element redistributes compressive stress evenly across the interface, preventing localized stress concentration while maintaining the overall simplicity of the stack assembly.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If specialized fuel end plates are used, then fuel cell protection is improved, but manufacturing costs increase

Engineering Contradiction:

Improvefuel cell protectionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The interconnect end plate is designed to perform multiple functions: it provides electrical connection between cells, serves as a structural support, incorporates a recessed region for the glass ring seal to prevent corrosion and manage stress, and interfaces with the fuel manifold. This multi-functionality eliminates the need for separate specialized fuel end plates, reducing manufacturing costs while maintaining fuel cell protection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20240332560A1Electrochemical cell stacks including interconnect end plates

Publication Date: 2024.10.03 BLOOM ENERGY CORP

AI summary

An electrochemical cell stack includes electrochemical cells that each contain a fuel electrode, an air electrode and an electrolyte disposed therebetween, interconnects disposed between the electrochemical cells, and an interconnect end plate disposed over the fuel electrode of an outermost one of the electrochemical cells. The interconnect end plate includes a fuel side, an opposing air side, fuel ribs disposed on the fuel side and at least partially defining fuel channels, air ribs disposed on the air side and at least partially defining dummy air channels, fuel holes extending from the fuel side to the air side, and recessed ring seal regions disposed on the air side surrounding the fuel holes.