SOFC Stack Assembly Using a Tensioned Skirt for Compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid oxide fuel cell (SOFC) stacks face challenges in maintaining compression and structural integrity due to thermal cycling, which can lead to reduced performance and risk of short circuits, especially with the use of tie-bars that require careful design and differ in design for various stack configurations, increasing complexity and cost.
Innovation Solution
A method of forming a metal-supported SOFC stack assembly that uses a skirt to maintain compressive load through tensile forces instead of tie-bars, reducing thermal mass and allowing for a larger surface area for the fuel cells, and incorporating expansion plates to compensate for thermal expansion, thus maintaining compressive force and preventing gas sealing and electrical conductivity loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tie-bars are used to maintain compression in the fuel cell stack, then structural integrity and compression maintenance are improved, but device complexity and risk of short circuits increase due to proximity to guide hole edges and thermal expansion issues
Solution Approach 1:
The patent removes tie-bars from the fuel cell stack assembly entirely, replacing them with a compression plate that applies compressive force to the fuel cell stack. This extraction eliminates the complexity associated with tie-bar design, installation, and maintenance while reducing the risk of short circuits between tie-bars and guide holes during thermal cycling.
2Duration of action of stationary object
If tie-bars are used to maintain compression, then compression load is maintained, but thermal mass increases and surface area for fuel cells is reduced
Solution Approach 1:
By removing tie-bars and replacing them with a compression plate, the patent reduces the thermal mass of the stationary components. The compression plate applies force more efficiently without the additional thermal mass of multiple tie-bars, thereby reducing the energy required to heat the assembly to operating temperature.
Solution Approach 2:
The patent transitions from a distributed compression approach using multiple tie-bars to a centralized compression approach using a single compression plate. This dimensional change allows for larger surface area of the fuel cell stack to be exposed and functional, while the compression force is applied through a concentrated area of the compression plate.
3Strength
If tie-bars are used for compression, then structural support is provided, but manufacturing complexity increases due to alignment and assembly requirements
Solution Approach 1:
The patent eliminates tie-bars and their associated guide holes, simplifying the manufacturing process. The compression plate can be positioned and secured without the need for precise alignment through multiple guide holes, reducing manufacturing complexity and assembly time.
Solution Approach 2:
The patent combines the functions of multiple tie-bars into a single compression plate that provides structural support and compression maintenance. This merging of functions simplifies the component count and assembly requirements, making manufacturing easier while maintaining the necessary structural support.
4Adaptability or versatility
If different tie-bar designs are used for different stack configurations, then adaptability is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces a universal compression plate design that can be adapted to different fuel cell stack configurations without requiring different tie-bar designs. The compression plate serves multiple functions: providing structural support, maintaining compression, and accommodating various stack arrangements, thereby reducing device complexity and cost while maintaining adaptability.
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 enhances the performance and lifespan of the fuel cell stack by reducing energy required to reach operating temperature, increasing power output, simplifying manufacturing, and minimizing the risk of short circuits, while eliminating the need for tie-bars and their associated complexities.
Implementation Method 1
maintain the stack compression through the tensile forces in the skirt
Implementation Method 2
incorporating expansion plates to compensate for thermal expansion, thus maintaining compressive force
Data Source
AI summary
The present invention is concerned with an improved fuel cell stack assembly comprising a metal base plate on which is mounted at least one fuel cell stack and a metal end plate, each stack comprising at least one fuel cell stack layer that comprises at least one fuel cell and at least one electrically insulating compression gasket, wherein a skirt is attached to the base and end plates enclosing the stack and is under tension therebetween so as to maintain a compressive force through the stack, thereby obviating the need for tie-bars.