Fuel Cell Separator With Varying Diffusion Flow Fields
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Solution Overview
Problem
Conventional fuel cell separators experience non-uniform flow rates in diffusion regions, leading to excessive flow in shorter paths, which affects the efficient distribution and discharge of reaction gases and coolant.
Innovation Solution
The separator design features diffusion flow fields with varying cross-sectional areas based on the flow path, utilizing protrusions of different heights and lengths to uniformly distribute the flow rate across different regions, ensuring consistent gas introduction and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separators with uniform diffusion flow fields are used, then the structure is simple and easy to manufacture, but the flow rate is non-uniform leading to excessive flow in shorter paths
Solution Approach 1:
The patent applies local quality by varying the cross-sectional area of diffusion flow fields in different regions. Specifically, the diffusion flow fields have different cross-sectional areas at ends adjacent to the reaction region compared to ends adjacent to the manifold region, creating non-uniform flow distribution that compensates for path length differences and achieves uniform flow rates across all regions.
Solution Approach 2:
The patent employs asymmetry by designing diffusion flow fields with asymmetric cross-sectional area distribution. The cross-sectional area changes along the flow path from the manifold region to the reaction region, creating an asymmetric geometry that balances the flow rates despite varying path lengths to different fuel cell regions.
2Reliability
If diffusion flow fields have varying cross-sectional areas, then flow rate distribution is uniform, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies parameter changes by modifying the cross-sectional area parameter of the diffusion flow fields along their length. The cross-sectional area is varied continuously or in steps from one end to the other, transforming the geometric parameter to achieve uniform flow distribution while maintaining a manufacturable design through controlled dimensional variations.
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 achieves uniform gas distribution and discharge, enhancing the durability of the fuel cell stack, preventing non-uniform electrochemical reactions, and reducing voltage deviations and cell shaking during operation.
Implementation Method 1
a pair of diffusion regions between the reaction region and the pair of manifold regions, wherein the pair of diffusion regions are configured to diffuse a flow of the fluid into or out of the reaction region
Data Source
AI summary
A separator for a fuel cell includes a reaction region, a pair of manifold regions on opposite sides of the reaction region and through which a plurality of manifolds pass, configured to introduce or discharge reaction gas or coolant, and a pair of diffusion regions between the reaction region and the manifold regions, configured to diffuse a flow of the reaction gas or coolant. Diffusion ribs in the diffusion regions are spaced apart from each other along the manifolds. The diffusion ribs may be spaced apart such that diffusion flow fields formed between the diffusion ribs have different cross-sectional areas for respective regions at ends adjacent to the manifold regions.