Spring Member Creep Deformation in Fuel Cell Stacks
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Solution Overview
Problem
In fuel cell stacks, the spring members used to press separators against power generation cells can experience creep deformation due to high temperatures, leading to reduced surface pressure and decreased power generation performance.
Innovation Solution
A spring member design with a planar portion joined to the separator, a spring portion generating elastic force through bending deformation, and auxiliary pillars to distribute stress and prevent creep deformation, ensuring consistent pressure and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spring member presses the separator toward the power generation cell at the end portion, then the separator is held firmly against the power generation cell, but stress concentrates at the end portion causing creep deformation at high temperatures
Solution Approach 1:
The spring member is divided into multiple pressing portions along its length, distributing the pressing function across multiple locations rather than concentrating it at a single end portion. This segmentation reduces stress concentration at any single point while maintaining overall holding force.
Solution Approach 2:
The spring member features varying cross-sectional areas along its length, with thicker sections at pressing portions and thinner sections in between. This creates local quality variations that concentrate stress at specific pressing points while reducing overall stress concentration, preventing creep deformation at high temperatures.
2Force
If the spring member undergoes bending deformation to generate elastic force, then the separator is pressed against the power generation cell, but the surface pressure decreases due to creep deformation at high temperatures
Solution Approach 1:
The spring member is designed to dynamically adjust its elastic force output based on temperature conditions. Through its segmented structure with varying cross-sectional areas, it maintains optimal surface pressure by distributing stress across multiple pressing portions, preventing the pressure loss that would result from creep deformation.
3Ease of manufacture
If the spring member is designed with a simple structure, then manufacturing is easier, but stress distribution is poor leading to creep deformation
Solution Approach 1:
The spring member employs parameter changes in its cross-sectional area along its length, creating a profile that is simple to manufacture yet effectively distributes stress. The varying thickness is achieved through straightforward manufacturing processes while achieving the complex stress distribution pattern needed to prevent creep deformation.
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 design effectively prevents creep deformation and maintains power generation performance by distributing stress and ensuring consistent surface pressure between the power generation cells and separators, even at high temperatures.
Implementation Method 1
a spring portion that extends from the planar portion and that generates an elastic force for pressing the separator toward the power generation cell by receiving a force in the stacking direction of the cell unit and undergoing bending deformation
Data Source
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AI summary
[PROBLEM] To provide a spring member, a fuel cell unit, and a fuel cell stack that can prevent a decrease in the power generation performance of a fuel cell caused by creep deformation of the spring member. [SOLUTION] A spring member 130 is used in a fuel cell stack 100 and comprises a planar portion 131 that is joined to a separator in a state of surface contact with the separator 102, and a spring portion 132 that extends from the planar portion to generate an elastic force that presses the separator toward a power generation cell 101M by receiving force in a stacking direction Z of a cell unit and undergoing bending deformation.