Alternating Pore Gas Diffusion Layer for Fuel Cells
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Solution Overview
Problem
The existing gas diffusion layers in fuel cells face issues with water flooding and clogging due to the selective movement of product water, which blocks the transfer of reactive gases and deteriorates cell performance.
Innovation Solution
A gas diffusion layer with alternately formed fine and coarse pore areas on a carbon fiber support, allowing reactive gases to flow through fine pores and product water to flow through coarse pores, facilitating separate and efficient transfer of both components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If product water moves through the gas diffusion layer via capillary pressure difference, then water removal is facilitated, but water concentrates in selected channels causing flooding and clogging
Solution Approach 1:
The gas diffusion layer is segmented into multiple types of pores (first type with smaller pore size and second type with larger pore size) that are distributed in an alternating pattern. This segmentation allows different pore types to perform different functions: smaller pores for gas transport and larger pores for water removal, preventing water concentration and flooding in any single channel while maintaining continuous gas transfer pathways.
2Ease of manufacture
If uniform pore size is used in the gas diffusion layer, then manufacturing is simplified, but water flooding occurs due to selective channel clogging
Solution Approach 1:
Different regions of the gas diffusion layer are designed with different pore characteristics. The layer contains first type pores with a first pore size and second type pores with a second pore size larger than the first. These different pore types are arranged in an alternating pattern, creating local variations in pore quality that optimize both water removal and gas transfer functions in different locations throughout the layer.
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 prevents water clogging by selectively directing product water through larger pores, ensuring uninterrupted gas transfer and improving fuel cell performance by maintaining a balance between pore sizes and proportions.
Implementation Method 1
the liquid-phase product water is moved through difference in capillary pressure in the gas diffusion layer 20 from the fine pore layer 22 to the carbon fiber support 21
Implementation Method 2
the gas diffusion layer 20 is obtained by forming a fine porous layer 22 on one or two surfaces of a carbon fiber support 21 generally including a porous carbon paper
Data Source
AI summary
In one embodiment, a gas diffusion layer for fuel cells includes a fine porous layer formed on a carbon fiber support and being interposed between a membrane-electrode assembly (MEA) and a separator. The carbon fiber support includes a fine pore area having a predetermined average pore size in a separator direction (thickness direction) in the membrane electrode assembly, and a coarse pore area having a larger predetermined average pore size than the average pore size of the fine pore area in the separator direction (thickness direction) in the membrane electrode assembly. The fine pore area and the coarse pore area are alternately formed.