Fuel Cell Cathode Separator with Inclined Gas Path Enlarging Portions
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Solution Overview
Problem
The use of a porous metal body as a gas path in fuel cells results in insufficient gas diffusivity and significant pressure drop, limiting the performance of the fuel cell.
Innovation Solution
A fuel cell design featuring stacked power generating unit cells with a porous body for the cathode separator and a path enlarging member with grooves that incline or are orthogonal to the gas flow direction, enhancing gas diffusivity and reducing pressure drop, while also incorporating cooling water path enlarging portions between gas path enlarging portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous metal body is used as a gas path in the cathode separator, then gas diffusion can be achieved, but gas diffusivity is insufficient and pressure drop is large
Solution Approach 1:
The cathode separator is divided into three functional regions: a porous body region for gas diffusion, and two gas path enlarging portions (first and second) with through-holes that segment the flow path. This segmentation allows gas to diffuse through the porous body while maintaining larger open paths for bulk flow, reducing pressure drop while preserving diffusion capability.
Solution Approach 2:
Different regions of the cathode separator are assigned different structural qualities: the central region uses a porous body structure optimized for gas diffusion, while the peripheral gas path enlarging portions use a mesh structure with larger through-holes optimized for low-resistance bulk flow. This local differentiation allows each region to perform its specific function optimally without compromising the other.
2Ease of operation
If a porous body is used for gas path, then gas flow can be controlled, but the path is too narrow causing significant pressure drop
Solution Approach 1:
The invention transitions from a two-dimensional porous surface to a three-dimensional structured path system. The gas path enlarging portions extend in the thickness direction with through-holes that create volumetric flow paths, adding a dimensional element that increases flow capacity while maintaining the porous body's surface-area-based diffusion control.
Solution Approach 2:
The gas path enlarging portions act as intermediary structures between the porous body and the external environment. They receive diffused gas from the porous body and provide a low-resistance transition path to the outlet, mediating between the diffusion-controlled narrow paths and the bulk flow requirements, thereby reducing overall pressure drop.
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 achieves excellent gas diffusivity and suppressed pressure drop, improving the overall performance of the fuel cell by optimizing gas and cooling water flow paths.
Implementation Method 1
a porous body where an oxidizing gas flows
Data Source
AI summary
Provided is a fuel cell having excellent gas diffusivity and leading to suppressed pressure drop even with a porous body as a gas path. The fuel cell includes: plural stacked power generating unit cells each having a membrane assembly, an anode separator stacked on the membrane assembly on one side, and a cathode separator stacked on the membrane assembly on the other side, wherein the anode separator of any one of the power generating unit cells is stacked on the cathode separator of another one thereof that is adjacent to said any one, the cathode separator has a porous body where an oxidizing gas flows, and a path enlarging member, and the path enlarging member includes gas path enlarging portions that enlarge a path formed by the porous body, the gas path enlarging portions having wall parts inclining or orthogonal to a direction where the oxidizing gas flows.