Fuel Cell Grid Spring Structure for Creep-Resistant Surface Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High spring constant spring members in fuel cell stacks undergo creep deformation at elevated temperatures, leading to reduced surface pressure between power generation cells and separators, which decreases power generation performance.
Innovation Solution
A dual-spring system where a first spring member with a high spring constant is used initially to maintain close contact during assembly, and a second spring member with a lower spring constant is activated upon heating to reduce reaction force and prevent creep deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spring member with a high spring constant is used to maintain close contact between components during assembly, then the components can be assembled in close contact with each other, but the spring member undergoes creep deformation at high temperatures during operation, leading to reduced surface pressure and decreased power generation performance
Solution Approach 1:
The spring member is divided into two functionally independent spring members: a first spring member that provides high spring constant during assembly to ensure close contact between components, and a second spring member that becomes active after the first spring member undergoes creep deformation at high temperatures. This segmentation allows each spring member to optimize its performance for its specific operational phase without compromising the other.
Solution Approach 2:
The invention utilizes temperature-dependent parameter changes in the spring members. The first spring member is designed with a high spring constant at room temperature for precise assembly, while its spring constant decreases at high temperatures due to creep deformation. The second spring member is designed to maintain its elastic properties at high temperatures, compensating for the first spring member's degradation and maintaining stable surface pressure during operation.
2Stress or pressure
If the spring constant of the spring member is increased to ensure sufficient surface pressure during operation, then the components remain in close contact, but the spring member is more prone to creep deformation at high temperatures, making it impossible to ensure sufficient surface pressure
Solution Approach 1:
The spring member is divided into two functionally independent spring members: a first spring member that provides high spring constant during assembly to ensure close contact between components, and a second spring member that becomes active after the first spring member undergoes creep deformation at high temperatures. This segmentation allows each spring member to optimize its performance for its specific operational phase without compromising the other.
Solution Approach 2:
The first spring member is designed to undergo creep deformation as a preliminary action during the transition from assembly to operation. This controlled deformation reduces the first spring member's reaction force at high temperatures, preventing excessive stress on components while the second spring member compensates to maintain adequate surface pressure.
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 dual-spring system maintains sufficient surface pressure and prevents power generation performance degradation by adjusting spring constant in response to temperature changes, ensuring stable operation of fuel cell stacks.
Implementation Method 1
a first spring member (121) that generates elastic force for pressing the separator (102) toward the power generation cell (101M)
Implementation Method 2
The spring constant of the first spring member decreases when the fuel cell stack is heated. Therefore, before the fuel cell stack is heated, the fuel cell stack functions as a high reaction force spring, and, after being heated, functions as a low reaction force spring
Data Source
Figure 1
Figure 2
Figure 3
AI summary
[PROBLEM] To provide a spring member, a fuel cell unit, a fuel cell stack, and a method for manufacturing a fuel cell stack that can prevent a decrease in the power generation performance caused by creep deformation of the spring member. [SOLUTION] A grid spring is provided with a first raised piece 130A that generate an elastic force for pressing a separator 102 toward a power generation cell and a second raised piece 130B that generate an elastic force independently of the first raised piece 130A, wherein the spring constant of the first raised pieces decreases as a result of the heating of the grid spring, the grid spring functions as a high reaction force spring as a result of the larger spring constant of the first spring member relative to the spring constant of the second spring member before heating, and, after being heated, the grid spring functions as a low reaction force spring as a result of the smaller spring constant of the first spring member before being heated.