Fuel Cell Gas Diffusion Electrode Microporous Layer Penetration
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Solution Overview
Problem
Existing gas diffusion electrodes for fuel cells suffer from insufficient water removal performance and power generation efficiency due to inadequate microporous layer penetration into the conductive porous substrate, leading to flooding and reduced durability.
Innovation Solution
A gas diffusion electrode with a microporous layer that has a penetration portion penetrating into the conductive porous substrate, with a penetration amount of 30% to 70% and an area ratio of 0.1% to 1% of regions passing through the thickness direction, along with a non-penetration portion having a fluorine intensity of 5 to 20, and a conductive porous substrate density of 0.15 to 0.5 g/cm³, enhancing water removal and power generation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-repellent-treated conductive porous substrate is used to enhance water removal performance, then water repellency is improved, but the fiber mesh is coarse which leads to large water drops and flooding
Solution Approach 1:
The patent applies a microporous layer made of porous material with controlled pore size distribution. This layer is formed by applying an ink containing electrically conductive microparticles to the water-repellent-treated conductive porous substrate, then drying and sintering it. The microporous structure enables fine water drop formation while maintaining water repellency, preventing flooding.
Solution Approach 2:
The gas diffusion electrode uses a composite structure combining a water-repellent-treated conductive porous substrate with a microporous layer. The substrate provides water repellency and electrical conductivity, while the microporous layer provides fine pore structure for controlled water drop formation. This composite approach resolves the contradiction between water removal performance and flooding prevention.
2Ease of manufacture
If the microporous layer does not penetrate into the conductive porous substrate, then manufacturing is simpler, but water removal performance and power generation efficiency are insufficient
Solution Approach 1:
The patent implements local penetration of the microporous layer into the conductive porous substrate at specific locations rather than uniform penetration throughout. This localized approach allows the microporous layer to reach the substrate pores in critical areas for water removal, enhancing power generation efficiency while avoiding the complexity of controlling uniform penetration across the entire structure.
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 solution provides high gas diffusivity, water removal performance, and durability for fuel cells, preventing flooding and maintaining power generation efficiency even under increased electric loads.
Implementation Method 1
the microporous layer has a portion that has penetrated into the conductive porous substrate
Implementation Method 2
a gas diffusion electrode substrate including a conductive porous substrate that has been subjected to water-repellent treatment is used to increase water repellency
Implementation Method 3
an ink having dispersed therein electrically conductive microparticles such as carbon black is applied to a water-repellent-treated conductive porous substrate, and the ink is then dried and sintered to provide a layer called microporous layer
Data Source
Figure 1
AI summary
A gas diffusion electrode including: a conductive porous substrate and a microporous layer on at least one side of the conductive porous substrate; in which the total of regions passing through the microporous layer in the thickness direction has an area ratio of 0.1% or more and 1% or less; and in which the microporous layer has a portion that has penetrated into the conductive porous substrate (hereinafter referred to as penetration portion), the penetration portion having a thickness ratio (hereinafter referred to as penetration amount) of 30% or more and 70% or less with respect to 100% of the thickness of the microporous layer. The gas diffusion electrode used for fuel cells affords fuel cells having high water removal performance and high power generation performance.