Porous Transport Layer With Density Gradient For PEM Water Electrolysis
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Solution Overview
Problem
In PEM water electrolysis systems, the porous transport layer on the cathode side faces challenges in efficiently discharging water, leading to reduced system efficiency and corrosion of the separator due to water diffusion, which interferes with hydrogen discharge and increases internal contact resistance.
Innovation Solution
A porous transport layer comprising multiple substrate layers with varying average densities, including a lower substrate layer with carbon fibers and polymer resin, an intermediate substrate layer with carbon fibers, and a microporous layer, where the second lower substrate layer has a lower average density than the first, facilitating easy water discharge and reducing separator corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a high-density carbon fiber structure is used in the porous transport layer, then structural strength and airtightness are improved, but water discharge efficiency deteriorates
Solution Approach 1:
The lower substrate layer is divided into multiple layers with different average densities. The first lower substrate layer has higher average density for structural strength, while the second lower substrate layer has lower average density for improved water discharge efficiency. This segmentation allows each layer to fulfill its specific function without compromise.
2Object-affected harmful factors
If water discharge efficiency is improved by using lower density structure, then separator corrosion is reduced, but structural strength deteriorates
Solution Approach 1:
The lower substrate layer is segmented into multiple layers with different average densities. The first lower substrate layer with higher average density provides the necessary structural strength, while the second lower substrate layer with lower average density facilitates water discharge and reduces separator corrosion. This segmentation allows each layer to fulfill its specific function without compromise.
3Device complexity
If a single-layer structure is used, then device complexity is reduced, but functional performance deteriorates
Solution Approach 1:
The lower substrate layer is segmented into multiple layers with different average densities to optimize both structural strength and water discharge efficiency. The first lower substrate layer has higher average density for structural strength, while the second lower substrate layer has lower average density for improved water discharge efficiency.
Solution Approach 2:
Different regions of the lower substrate layer are assigned different average densities according to their specific functional requirements. The first lower substrate layer has higher average density where structural strength is needed, while the second lower substrate layer has lower average density where water discharge is prioritized.
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 layered structure effectively reduces contact resistance and prevents separator corrosion by separating hydrogen and moisture flow paths, enhancing the durability and efficiency of the PEM water electrolysis system.
Implementation Method 1
a porous transport layer for a cathode and a water electrolysis cell comprising the same that comprise at least two lower substrate layers with different average densities to make it easy to discharge water
Data Source
AI summary
The present disclosure relates to a porous transport layer for a cathode comprising carbon fibers and polymer resin, an intermediate substrate layer disposed on the lower substrate layer and containing carbon fibers, and a microporous layer disposed on the intermediate substrate layer. The lower substrate layer may comprise a first lower substrate layer, and a second lower substrate layer disposed on the first lower substrate layer and having an average density lower than an average density of the first lower substrate layer. The intermediate substrate layer may be disposed on the second lower substrate layer. A water electrolysis cell may comprise the porous transport layer and the cathode.