Fuel Cell Stack Fastening with Elastic Load Adjustment
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Solution Overview
Problem
Existing fuel cell stack fastening methods struggle to apply a uniform and adjustable fastening load due to variations in thickness and length, leading to issues of excessive or insufficient fastening, increased volume, and reduced power generation performance.
Innovation Solution
A polymer electrolyte fuel cell stack utilizing paired U-curved plate-like fastening members with coupling portions and pin members to apply a uniform load, allowing for easy adjustment by replacing pin members of different dimensions or shapes, thereby ensuring appropriate and even fastening without additional load adjustment mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional fastening methods (bolts, metal belts) are used to fasten the fuel cell stack, then the stack can be mechanically secured, but the fastening load cannot be uniformly adjusted due to variations in thickness and length, leading to excessive or insufficient fastening
Solution Approach 1:
The patent applies parameter changes by using elastic bodies (springs) with adjustable stiffness coefficients and precompression forces. By changing the physical parameters of the elastic bodies (k, F0), the fastening load can be precisely adjusted to match variations in stack thickness and length, achieving uniform fastening across different configurations without requiring complex adjustment mechanisms.
Solution Approach 2:
The patent implements beforehand cushioning by pre-compressing elastic bodies between the end plates and the stacked product. This precompression creates a buffer that automatically compensates for thickness variations and ensures uniform fastening load distribution from the outset, preventing both excessive and insufficient fastening without requiring post-assembly adjustments.
2Ease of operation
If additional load adjustment mechanisms are added to achieve uniform fastening, then fastening load adjustability improves, but device complexity and volume increase
Solution Approach 1:
The patent applies self-service by designing a fastening system where elastic bodies automatically adjust to thickness variations through their inherent elasticity. The system self-regulates the fastening load based on the stacked product's dimensions without requiring external adjustment mechanisms, sensors, or control systems, thereby maintaining simplicity while achieving uniform fastening.
Solution Approach 2:
Instead of adding complex adjustment mechanisms, the patent changes the parameters of existing components (elastic bodies) to achieve adjustability. By selecting elastic bodies with appropriate stiffness and precompression forces, the system adapts to different stack configurations without increasing structural complexity.
3Reliability
If conventional fastening methods are used, then the stack can be assembled, but power generation performance and durability are reduced due to non-uniform fastening load
Solution Approach 1:
The patent uses beforehand cushioning through pre-compressed elastic bodies to ensure uniform fastening load distribution across the entire stack from the beginning. This uniform pressure prevents localized stress concentrations that could damage the stacked product, thereby improving reliability, power generation performance, and durability without requiring complex control systems.
Solution Approach 2:
By adjusting the parameters of elastic bodies (stiffness k and precompression force F0), the patent optimizes the fastening load uniformity to enhance the reliability and performance of the fuel cell stack. The parameter optimization ensures that the fastening system delivers consistent pressure across varying thickness and length configurations.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
When assembly is carried out by clamping a stacked product (7) made up of a plurality of unit cell modules (2), paired end plates (4A, 4B) respectively disposed on both the sides thereof and the like by a plurality of fastening members (8A, 8B, 8F), first coupling portions (9) of one end portion of each of such plurality of fastening members and second coupling portions (9) of the other end portions are combined to each other, and coupled with one pin member (10, 10A, 10B, 10E, 10G). Thus, a plurality of such fastening members are coupled.