Fuel Cell Stack End Plate Segmentation for Thermal Isolation
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Solution Overview
Problem
Conventional fuel cell stacks inefficiently recover heat generated during power generation as it is conducted to end plates and radiated outside, rather than being recovered as thermal energy.
Innovation Solution
Reducing the contact area between end plates and collector plates, and between end plates and elastic members, by designing end plates with convexed and concaved portions to minimize heat conduction, and using elastic members like coil springs to apply uniform load and reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If end plates are made with large contact area to collector plates, then structural stability and load distribution are improved, but heat loss increases as more heat is conducted to end plates and radiated outside
Solution Approach 1:
The end plate contact surface is segmented into multiple convexed portions distributed across the plate, rather than having a single large continuous contact area. This segmentation reduces the total contact area between end plates and collector plates, thereby reducing heat conduction to the end plates while still providing adequate structural support and load distribution through the distributed convexed portions.
Solution Approach 2:
The end plates incorporate convexed portions with specific local geometric properties (height, diameter, spacing) that optimize the balance between mechanical support and thermal isolation. The local quality of these convexed portions allows them to provide necessary structural stability while minimizing the overall heat transfer area, addressing both structural and thermal requirements simultaneously.
2Power
If elastic members are used to apply uniform load to cell assembly, then power generation efficiency is improved, but heat conduction to end plates increases through the elastic members
Solution Approach 1:
The load application is segmented through multiple discrete elastic members (coil springs) positioned at specific locations around the cell assembly, rather than using a single continuous elastic element. This segmentation allows for uniform load distribution across the cell assembly while minimizing the total thermal conduction path to the end plates, as each spring provides localized support with minimal thermal mass.
Solution Approach 2:
The convexed portions on the end plates serve as intermediary structures between the elastic members and the collector plates. These convexed portions provide the necessary mechanical interface for load transmission while their reduced contact area minimizes thermal conduction, effectively mediating between the mechanical support function and thermal isolation requirement.
3Loss of energy
If end plates have convexed and concaved portions, then heat recovery efficiency is improved by reducing heat conduction, but manufacturing complexity increases
Solution Approach 1:
The end plates incorporate convexed portions with curved surfaces rather than flat or angular geometries. These curved surfaces naturally reduce the contact area with collector plates and elastic members, improving heat recovery efficiency. The curvature also provides mechanical strength and ease of formation through common manufacturing processes such as molding or machining, balancing thermal performance with manufacturability.
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 design enhances heat recovery efficiency and maintains high power generation efficiency by minimizing heat loss and preventing end plate deformation, allowing for effective utilization of heat as thermal energy.
Implementation Method 1
an elastic member disposed between end plate A and collector plate A
Implementation Method 2
heat generated during power generation is conducted to the end plates from the cell assembly
Data Source
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AI summary
Disclosed is a fuel cell stack which includes: a cell assembly formed of stacked unit cells, each composed of a membrane electrolyte assembly and separators which sandwich the membrane electrolyte assembly; a pair of collector plates A and B which sandwiches the cell assembly; a pair of end plates A and B which sandwiches the cell assembly and the collector plates; and an elastic member disposed between end plate A and collector plate A, wherein end plate A has a convexed portion and a concaved portion on a surface facing collector plate A, and the concaved portion of end plate A holds therein the elastic member, and a bottom surface of the concaved portion includes a second convexed portion and a second concaved portion.