Micro-porous Layer Cracking Prevention in Fuel Battery Electrodes
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Solution Overview
Problem
Existing micro-porous layers in solid polymer electrolyte fuel batteries face issues with cracking, water vapor aggregation, and non-uniform catalyst coating due to high molecular weight binders and thermosetting resins, leading to reduced power generation performance and durability.
Innovation Solution
A micro-porous layer with a fibrous carbide having a specific fiber diameter and aspect ratio, combined with a water-repellent substance, is developed, featuring a high contact angle and minimal cracking, allowing for uniform catalyst coating and improved gas diffusibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a micro-porous layer is formed by drying and sintering ink containing conductive material, fluororesin particles as binder, and surfactant, then the micro-porous layer provides water vapor aggregation prevention, but the conductive material largely moves and aggregates during drying to cause cracks
Solution Approach 1:
The patent introduces a polyol as an intermediary substance that mediates between the conductive material particles and the fluororesin binder. The polyol forms a flexible matrix that allows conductive material particles to move during drying without causing cracks, while still maintaining the micro-porous structure needed for water vapor aggregation prevention.
Solution Approach 2:
The patent changes the physical and chemical parameters of the binder system by replacing traditional high molecular weight water repellent and thermosetting resins with a polyol-based system. This parameter change allows the binder to remain flexible during drying and sintering, preventing crack formation while maintaining binding functionality.
2Manufacturing precision
If high molecular weight water repellent is used as binder, then cracks are suppressed during drying, but water repellency is insufficient and catalyst coating liquid cannot be applied uniformly
Solution Approach 1:
The patent changes the molecular weight parameter of the binder from high molecular weight (which provides crack suppression but poor water repellency) to a specific range of low molecular weight polyol (which provides both crack suppression and adequate water repellency). This parameter optimization resolves the contradiction between crack suppression and water repellency.
3Manufacturing precision
If thermosetting resin is added to form micro-porous layer, then cracks are suppressed during drying and sintering, but water repellency is insufficient and catalyst coating liquid cannot be applied uniformly
Solution Approach 1:
The patent replaces thermosetting resins with a polyol-based binder system, changing the chemical nature of the binder. The polyol provides flexibility during processing to suppress cracks while maintaining appropriate water repellency properties, eliminating the need for thermosetting resins and their associated problems with water repellency.
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 results in a fuel battery with enhanced productivity, power generation performance, and durability by preventing flooding and ensuring uniform catalyst application, while maintaining flexibility and avoiding electrolyte membrane damage.
Implementation Method 1
a water-repellent substance, is developed, featuring a high contact angle and minimal cracking
Implementation Method 2
improved gas diffusibility
Data Source
AI summary
The present invention provides a micro-porous layer which provides a fuel battery having high productivity, high power generation performance, and high durability. The present invention provides a micro-porous layer including fibrous carbohydrate having a fiber diameter of 5 nm-10 μm and an aspect ratio of 10 or more. The carbohydrate has an oxygen/carbon element ratio of 0.02 or more.