Polyamide Multilayer Hydrogen Sealing Structure
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Solution Overview
Problem
Hydrogen storage tanks and transport pipes face challenges in minimizing contaminant extraction from thermoplastic sealing layers, which can degrade fuel cell performance and durability, especially due to volatile organic compounds and water trapped during manufacturing, and require materials with low hydrogen permeability and mechanical strength at varying temperatures.
Innovation Solution
A multilayer structure using a sealing layer composed of polyamide, which satisfies contaminant extraction tests by limiting contaminants to less than 3% by weight, ensuring minimal contamination of hydrogen, thereby maintaining fuel cell performance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thermoplastic sealing layer is used in hydrogen storage tanks and transport pipes, then the tank can be manufactured with good mechanical properties and low cost, but contaminants such as volatile organic compounds and water are extracted from the sealing layer during hydrogen contact, degrading fuel cell performance
Solution Approach 1:
The sealing layer is divided into multiple functional layers: an inner layer in direct contact with hydrogen made from polyamide with low contaminant extraction, and an outer layer providing mechanical strength and environmental resistance. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between manufacturability and contaminant control.
Solution Approach 2:
Different regions of the sealing layer are assigned different material properties: the inner layer uses polyamide specifically selected for low volatile organic compound and water content to minimize contaminant extraction, while the outer layer uses materials optimized for mechanical strength and temperature resistance. This local differentiation resolves the contradiction by addressing contaminant control where it matters most (at the hydrogen interface).
2Reliability
If the sealing layer is made with high polyamide content to reduce contaminant extraction, then fuel cell durability is improved, but the mechanical strength and impact resistance of the tank may be reduced
Solution Approach 1:
The sealing layer is segmented into an inner layer (60-90 wt% polyamide) optimized for low contaminant extraction to protect the fuel cell, and an outer layer optimized for mechanical strength and impact resistance. This segmentation resolves the contradiction by distributing the functional requirements across different layers rather than requiring a single material to satisfy all constraints.
Solution Approach 2:
The sealing layer uses a composite structure combining polyamide-based materials with different formulations in inner and outer layers. The inner layer uses high-polyamide content material for chemical compatibility and low extraction, while the outer layer incorporates materials with enhanced mechanical properties. This composite approach resolves the contradiction between reliability and strength.
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 polyamide-based multilayer structure effectively reduces contaminant extraction from the sealing layer, ensuring hydrogen purity and extending fuel cell lifespan by maintaining low contaminant levels, thus addressing the limitations of existing hydrogen storage and transport systems.
Implementation Method 1
the permeability of the liner is a key factor in limiting hydrogen losses from the tank
Implementation Method 2
contaminants present in the hydrogen and extracted from the sealing layer by the hydrogen
Data Source
AI summary
The use of a sealing layer of a composition including at least one polyamide for preparing a multicore structure intended for the transport, distribution or storage of hydrogen, in particular for the distribution or storage of hydrogen, especially for the storage of hydrogen, the sealing layer satisfying a test for contaminants present in the hydrogen and extracted from the sealing layer after contact of the hydrogen with same, the test been carried out as defined in the standard CSA/ANSI CHMC 2: 19, the total proportion of said contaminants extracted in the hydrogen being less than or equal to 3% by weight, in particular less than 2% by weight of the sum of the constituents of the composition.