Fuel Cell Stack Seals for Corner Stress Relief

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Solution Overview

Problem

Fuel cell stacks face challenges with compressive stress on corners during assembly and sintering, leading to potential damage and reduced performance due to complex fuel distribution systems and density variations in conventional interconnect designs.

Innovation Solution

The method involves using cross-flow interconnects with stress reduction seals, including riser seals and perimeter seals with support portions and extensions, to reduce compressive stress on fuel cells during assembly and sintering, and depositing a liquid seal material that solidifies after pressing the fuel cell into it, ensuring uniform fuel distribution and contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional interconnect designs with complex fuel distribution systems are used, then fuel can be distributed to cells, but compressive stress concentrates on corners of fuel cells during assembly and sintering causing damage

Engineering Contradiction:

Improvefuel distributionVSAvoidcompressive stress on corners

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The seal material is applied selectively at specific locations on the interconnect - at the periphery and at corners - to provide localized stress relief exactly where needed during assembly and sintering, while maintaining fuel distribution functionality in other areas

Inventive Principle:

Principle #3Local quality

2Reliability

If seal material is deposited on interconnect to form seals, then contact area is maintained, but density variations in conventional designs cause non-uniform stress distribution

Engineering Contradiction:

Improvecontact areaVSAvoidstress distribution uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Different seal configurations are used at different locations: periphery seals maintain contact area along edges, while corner seals specifically address stress concentration at corners, creating locally optimized stress distribution across the fuel cell assembly

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The seal material is applied to the interconnect before assembly, pre-positioning stress-relief features that will actively reduce compressive stress on fuel cell corners during the subsequent assembly and sintering processes

Inventive Principle:

Principle #10Preliminary action

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

This approach minimizes damage to fuel cells, enhances uniformity in fuel distribution, and improves the overall performance and efficiency of the fuel cell stack by reducing stress and maintaining contact area, thereby increasing operational efficiency and longevity.

Implementation Method 1

sintering the fuel cell stack to reflow the riser seals and the perimeter seal

Methodology Applied

Scientific EffectSintering: Sintering

Implementation Method 2

depositing a liquid seal material that solidifies after pressing the fuel cell into it

Methodology Applied

Scientific EffectPhase change (solidification): Phase Change

Data Source

PatentUS12136756B1Method of making a fuel cell stack with stress reducing seals

Publication Date: 2024.11.05 BLOOM ENERGY CORP

AI summary

A method of assembling a fuel cell stack includes depositing a liquid seal material on an interconnect, pressing a fuel cell into the liquid seal material, and solidifying the liquid seal material after pressing the fuel cell into the liquid seal material. The seal material may also include a support portion or extensions which are configured to reduce an amount of compressive stress on corners of the fuel cell in the fuel cell stack.