Corrugated SOFC Stack Architecture for Thermal Stress Compliance
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Solution Overview
Problem
Existing solid oxide fuel cell (SOFC) and solid oxide electrolysis cell (SOEC) stacks face challenges in achieving marketable price, reasonable performance, and useful lifetime, particularly in terms of power density, volume, weight, and thermal management.
Innovation Solution
The development of high power density compact SOFC stacks with corrugated interconnects that form fuel and oxidant channels, sealed via sealing members to provide compliance and reduce thermal stress, while also optimizing the integration of components for smaller cell sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional rigid interconnects are used in SOFC stacks, then structural strength is maintained, but thermal stress accumulates and compliance is reduced
Solution Approach 1:
The interconnects incorporate corrugated structures with curved wave patterns instead of flat rigid surfaces. These corrugations allow the interconnects to flex and expand/contract in response to thermal cycling while maintaining structural integrity, thus providing compliance without sacrificing strength.
Solution Approach 2:
The interconnect geometry is modified by introducing corrugations that change the mechanical parameters of the structure. The wave-like profile alters the stiffness and flexibility characteristics, enabling the interconnect to accommodate thermal expansion and contraction while maintaining adequate structural strength.
2Ease of manufacture
If larger cell sizes are used in SOFC stacks, then manufacturing and sealing are easier, but power density per unit volume decreases
Solution Approach 1:
The stack is divided into multiple smaller cell units arranged in series, with each cell separated by individual interconnects. This segmentation allows for easier sealing at each interface while achieving high overall power density through the cumulative effect of multiple compact cells.
Solution Approach 2:
The design transitions from large planar cells to a three-dimensional stacked configuration with multiple smaller cells arranged vertically. This dimensional approach increases power density by utilizing vertical space efficiently while maintaining manageable cell sizes for manufacturing and sealing.
3Reliability
If more material is used in interconnects, then structural strength and durability improve, but weight and volume increase
Solution Approach 1:
The interconnects are designed as thin-walled corrugated structures that provide adequate mechanical strength and durability through their geometric configuration rather than material thickness. The corrugated profile acts as a structural reinforcement, allowing thin materials to achieve the required durability without excessive weight.
Solution Approach 2:
The interconnects utilize composite construction combining thin metal substrates with protective coatings or ceramic layers. This composite approach provides enhanced durability and thermal resistance while minimizing weight, as the thin base material provides structural integrity and the coatings provide protective functions.
4Ease of manufacture
If uniform interconnect design is used, then manufacturing is simpler, but thermal stress distribution becomes non-uniform
Solution Approach 1:
The corrugated interconnects feature asymmetric wave patterns with varying amplitudes and wavelengths along their length. This asymmetric geometry creates non-uniform flexibility zones that distribute thermal stress more evenly across the stack, with stiffer regions accommodating expansion and more flexible regions absorbing stress concentrations.
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 results in stacks with significantly reduced material content, achieving higher power density per unit weight and volume, improved thermal control, and potential cost reductions, while maintaining or improving performance and longevity.
Implementation Method 1
the interconnects configured to provide compliance to the electrochemical cell stack
Implementation Method 2
fluidly isolated via sealing members
Implementation Method 3
Oxygen reacts with electrons at the cathode to form oxygen ions, which are conducted through the ion-conducting ceramic electrolyte to the anode. At the anode, oxygen ions combine with available fuel to form products thereby liberating electrons to produce electrical power
Implementation Method 4
the corrugations forming a plurality of fuel channels on one side and a plurality of oxidant channels on the opposite side
Data Source
AI summary
A top compression plate assembly for an electrochemical cell stack includes a top end plate configured to interface with a top end of a stack of electrochemical cells, a top compression plate positioned on the top end plate, and a plurality of springs coupled to a periphery of the top compression plate. The springs are configured to cause the top compression plate to exert a compressive force on the top end plate.