Fuel Cell Stack Assembly with Ceramic Side Baffles
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Solution Overview
Problem
The existing fuel cell stack systems face efficiency losses due to heat sinks created by bores or feed-throughs, which also require costly tie rods for compressive load application, and thermal expansion issues between ceramic baffles and metal components.
Innovation Solution
The redesign of the fuel cell stack assembly eliminates bores and tie rods by using ceramic side baffles that apply compressive stress directly, with a laminate structure and controlled coefficient of thermal expansion to match the fuel cell stacks, and incorporates a compression assembly with a ceramic leaf spring for efficient load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If bores or feed-throughs are used in ceramic side baffles to apply compressive load via tie rods, then the compressive load on fuel cell stacks is maintained, but heat sinks are created that decrease system efficiency
Solution Approach 1:
The invention removes the bores and tie rods from the ceramic side baffles, extracting the harmful heat sink elements while preserving the compressive load application function through an alternative mechanism using metal support blocks and compression springs
Solution Approach 2:
Metal support blocks are introduced as intermediary elements between the ceramic side baffles and the fuel cell stacks. These blocks provide the mechanical connection for applying compressive load without requiring bores through the ceramic baffles, thereby eliminating heat sinks while maintaining structural integrity
2Ease of manufacture
If ceramic side baffles with different CTE than fuel cell stacks are used, then manufacturing ease is improved, but thermal expansion issues arise during operation
Solution Approach 1:
The side baffle assembly uses a composite structure combining ceramic baffles with metal support blocks. The ceramic provides chemical inertness and electrical insulation, while the metal blocks provide mechanical support and have CTE values matched to the fuel cell stacks, resolving the thermal expansion compatibility issue
3Force
If tie rods and bores are used to apply compressive load, then load application is achieved, but device complexity and cost increase
Solution Approach 1:
The invention eliminates the complex tie rod and bore system by using simpler metal support blocks with integrated compression springs that directly apply compressive load to the fuel cell stacks through the ceramic side baffles
Solution Approach 2:
The invention changes the mechanical parameter application method from tensile load through tie rods to direct compressive load through spring-loaded metal blocks, simplifying the overall structure while achieving the same functional outcome
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 configuration enhances system efficiency by eliminating heat sinks, reduces thermal expansion issues, and allows for improved load distribution, increasing the compressive load on the fuel cell stacks while maintaining structural integrity and reducing operational costs.
Implementation Method 1
The side baffles have a first coefficient of thermal expansion (CTE) at room temperature, the column has a second CTE at room temperature, and the first CTE is within +/â20%, such as within +/â10% of the second CTE
Implementation Method 2
The compression spring assembly applies a load directly to the lower pressure plate 90 and to the upper pressure plate 230 via the tie rods 222
Data Source
AI summary
A fuel cell stack assembly and method of operating the same are provided. The assembly includes a fuel cell stack column and side baffles disposed on opposing sides of the column. The side baffles and the fuel cell stack may have substantially the same coefficient of thermal expansion at room temperature. The side baffles may have a laminate structure in which one or more channels are formed.