SOFC Separator Manifold Design for Thermal Stability

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Solution Overview

Problem

Solid oxide fuel cell (SOFC) stacks face durability issues due to thermal, mechanical, and chemical stresses, particularly in plate-type configurations, leading to problems like interlayer peeling and microcracking, especially with nonuniform temperature and reactant distribution.

Innovation Solution

A separator design for SOFC stacks with specific manifold configurations, including elliptical outlet and inlet manifolds, is introduced to minimize thermal gradients and optimize flow patterns, allowing for counter-flow and cross-flow arrangements that reduce pressure differences and enhance power density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If plate-type SOFC unit cells are used to achieve high power density per unit volume, then productivity is improved, but reliability deteriorates due to thermal and mechanical stresses causing interlayer peeling and microcracking

Engineering Contradiction:

Improvepower density per unit volumeVSAvoiddurability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The separator is designed with different regional characteristics: the center portion has a specific thickness and material composition, while the peripheral portion has varying thickness and integrated manifold structures. This local differentiation allows the separator to provide structural support where needed while managing thermal and stress distributions across different regions of the plate-type unit cell, thereby improving reliability without sacrificing power density.

Inventive Principle:

Principle #3Local quality

2Productivity

If plate-type SOFC unit cells are stacked to increase power output, then productivity is improved, but stability deteriorates due to nonuniform temperature and reactant distribution

Engineering Contradiction:

Improvepower outputVSAvoidthermal stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The separator's thickness is varied as a parameter: the center portion has a first thickness while the peripheral portion has a second thickness different from the first. This thickness variation is designed to compensate for nonuniform temperature and reactant distributions in stacked plate-type cells, improving thermal stability and operational reliability without reducing power output.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If manifolds are added to improve reactant distribution, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveuniformity of reactant distributionVSAvoidmanifold configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The manifold structures are merged directly into the peripheral portion of the separator itself, rather than being separate components. The inlet and outlet manifolds are formed as integrated features of the separator's peripheral region, simplifying the overall device structure while still achieving improved reactant distribution across the plate-type unit cells.

Inventive Principle:

Principle #5Merging (Combining)

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 separator design improves the durability and power density of SOFC stacks by minimizing thermal gradients and reducing pressure differences, leading to improved thermal stability and increased power output per unit volume.

Implementation Method 1

the separator design improves the durability and power density of SOFC stacks by minimizing thermal gradients

Methodology Applied

Scientific EffectThermal gradient: Temperature Gradient

Implementation Method 2

allowing for counter-flow and cross-flow arrangements that reduce pressure differences and enhance power density

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS10840533B2Separator for a fuel cell and a fuel cell stack comprising the same

Publication Date: 2020.11.17 KOREA INST OF SCI & TECH

AI summary

This application relates to a separator for a fuel cell and a fuel cell stack with improved durability, which contains the same, particularly to a solid oxide fuel cell stack. Specifically, this application allows an oxidizer and a fuel to flow in a counter-flow manner and a cross-flow manner in the fuel cell stack by forming an outlet manifold and an inlet manifold to have a specific shape, location and size in the separator. As a result, interlayer peeling, microcracking, etc. are prevented because no variation in temperature, reactant concentration, power, etc. occurs between each unit cell and the power density per unit volume is significantly improved because the volume is minimized.