Fuel Cell Gas Diffusion Electrode Substrate with Microporous Layer
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Solution Overview
Problem
Conventional gas diffusion electrode substrates for fuel cells can cause short circuits and reaction gas leakage due to carbon fibers protruding from the surface, leading to reduced power generation performance over time.
Innovation Solution
A gas diffusion electrode substrate with a microporous layer comprising a dense portion A and a dense portion B, where portion A has a fluorine resin and carbonaceous powder with a primary particle size of 20-39 nm, and portion B has a fluorine resin and carbonaceous powder with a primary particle size of 40-70 nm, applied on an electrically conductive porous substrate to enhance durability and flooding resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water-repellent-treated electrically conductive porous substrate is used to enhance water drainage, then flooding resistance is improved, but the coarse fiber mesh produces large water drops that easily lead to flooding
Solution Approach 1:
The invention applies a microporous layer on the water-repellent-treated substrate. This microporous layer contains numerous small pores that can hold and transport water in small droplets rather than large drops, preventing flooding while maintaining water drainage capability
Solution Approach 2:
The invention creates a composite structure combining the water-repellent-treated electrically conductive porous substrate with a microporous layer. This composite material integrates the water repellency of the substrate with the water transport capability of the microporous layer, resolving the contradiction between water drainage and flooding prevention
2Reliability
If carbon fibers are used in the gas diffusion electrode substrate, then electrical conductivity and mechanical strength are improved, but carbon fiber protrusions cause short circuits and reaction gas leakage
Solution Approach 1:
The microporous layer acts as a flexible thin film coating on the carbon fiber substrate. This thin film layer smooths the surface, preventing carbon fiber protrusions from piercing the membrane while maintaining electrical conductivity through the carbonaceous powder in the microporous layer
Solution Approach 2:
The microporous layer serves as an intermediary between the carbon fiber substrate and the membrane. It mediates the interaction by providing a smooth interface that prevents direct contact between protruding carbon fibers and the membrane, thereby preventing short circuits and gas leakage
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 substrate achieves both short circuit resistance and flooding resistance, resulting in high power generation performance and durability for fuel cells.
Implementation Method 1
the microporous layer includes a dense portion A and a dense portion B; wherein the dense portion B is provided with concaves in which the dense portion A is formed later
Implementation Method 2
the dense portion A is a region including a fluorine resin and a carbonaceous powder
Data Source
Figure 1~2
AI summary
Problem: A gas diffusion electrode substrate satisfying both short circuit resistance and flooding resistance and having high durability and good power generation performance is provided. Solution: A gas diffusion electrode substrate having: an electrically conductive porous substrate and a microporous layer 1 on one side of the electrically conductive porous substrate; in which the microporous layer 1 includes a dense portion A and a dense portion B; in which the dense portion A is a region containing a fluorine resin and a carbonaceous powder having a primary particle size of 20 nm to 39 nm; in which the dense portion A has a thickness of 30% to 100% with respect to the thickness of the microporous layer 1 as 100% and a width of 10 µm to 200 µm; and in which the dense portion B is a region containing a fluorine resin and a carbonaceous powder having a primary particle size of 40 nm to 70 nm.