Multilayer Gas Tank Structure for High-Temperature Hydrogen Storage
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Solution Overview
Problem
Current hydrogen storage tanks face challenges such as high weight, high cost, microcracking leading to mechanical strength variability, and difficulties in recycling due to the use of thermosetting resins. Additionally, the temperature resistance of these tanks is too low, hindering rapid filling and increasing production costs.
Innovation Solution
A tank with a multilayer structure comprising a semi-crystalline thermoplastic polyamide sealing layer, an intermediate composite reinforcing layer with a low glass transition temperature, and an outer composite reinforcing layer made of polyphthalamide with a high glass transition temperature. This configuration reduces residual mechanical stresses, enhances gas sealing, and allows for easier recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermosetting resins are used for the sealing layer and composite reinforcing layers, then the tank achieves high mechanical resistance and structural stability, but the tank suffers from microcracking leading to mechanical strength variability and difficulty in recycling
Solution Approach 1:
The patent changes the material parameter from thermosetting resin to semi-crystalline thermoplastic polyamide, fundamentally altering the chemical and physical properties of the tank structure. This parameter change eliminates microcracking while maintaining mechanical resistance, as thermoplastic materials do not exhibit the same microcrack formation behavior as thermosetting resins.
Solution Approach 2:
The patent employs a composite structure with multiple layers having different material compositions: a semi-crystalline thermoplastic polyamide sealing layer, an intermediate layer with semi-aromatic polyamide and carbon fibers, and an outer layer with polyphthalamide and carbon fibers. This composite approach optimizes both mechanical strength and reliability by combining materials with complementary properties.
2Ease of manufacture
If the tank uses a simple single-layer structure, then the manufacturing process is simpler and cost is reduced, but the tank cannot achieve sufficient temperature resistance and mechanical performance
Solution Approach 1:
The patent divides the tank structure into three distinct functional layers, each with specific material compositions optimized for particular requirements. The sealing layer provides hydrogen barrier properties, the intermediate layer provides structural reinforcement with carbon fibers, and the outer layer provides high-temperature resistance. This segmentation allows each layer to be optimized independently while maintaining overall manufacturing efficiency.
3Temperature
If the tank uses materials with high glass transition temperature for the entire structure, then the tank achieves high temperature resistance, but residual mechanical stresses increase and manufacturing complexity increases
Solution Approach 1:
The patent applies the local quality principle by assigning different glass transition temperatures to different layers based on their specific functional requirements. The sealing layer uses semi-crystalline thermoplastic polyamide with moderate Tg optimized for sealing performance, the intermediate layer uses semi-aromatic polyamide with higher Tg for structural stability, and the outer layer uses polyphthalamide with high Tg for temperature resistance. This localized optimization reduces overall residual stresses while maintaining necessary temperature resistance.
4Adaptability or versatility
If the tank uses different materials for sealing layer and composite reinforcing layers, then the tank achieves functional optimization, but recyclability becomes difficult
Solution Approach 1:
The patent changes the fundamental material parameter from thermosetting to thermoplastic across all layers, enabling recyclability while maintaining functional optimization. The semi-crystalline thermoplastic polyamide sealing layer and polyamide-based composite layers can be melted and reprocessed, allowing for recycling and reuse of the tank materials without compromising their sealing, structural, or temperature resistance functions.
Data Source
AI summary
A tank comprising a multi-layer structure, for storing compressed gas, including in succession from inside to outside at least the three following layers: at least one sealing layer of a composition including at least one semi-crystalline thermoplastic polyamide having a Tm of less than or equal to 280° C., at least one intermediate composite reinforcing layer of a fibrous material in the form of continuous fibres impregnated with a composition including at least one semi-crystalline thermoplastic polyamide having a Tg of less than 100° C., at least one outer composite reinforcing layer of a fibrous material in the form of continuous fibres impregnated with a composition including at least one polyphthalamide having a Tg of greater than 80° C., the outermost sealing layer being welded to the innermost intermediate composite reinforcing layer and the outermost intermediate composite reinforcing layer being welded to the innermost outer composite reinforcing layer.