Hydrogen Tank Multilayer Liner for Heat and Permeation Resistance
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Solution Overview
Problem
Existing hydrogen tanks face challenges with low thermal resistance, high permeability to hydrogen, and limited mechanical strength, especially at extreme temperatures, which hinder efficient hydrogen storage and filling speed.
Innovation Solution
A multilayer structure comprising a sealing layer made of polyamide, catalyst, thermal stabilizer, oligo- or poly-carbodiimide, and optionally polyolefin, combined with a composite reinforcing layer of fibrous material impregnated with epoxy resin, enhances mechanical strength and thermal resistance, reducing hydrogen permeability and allowing higher filling speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If HDPE is used as the liner material, then the manufacturing process is simple, but the thermal resistance is insufficient and hydrogen permeability is high
Solution Approach 1:
The patent uses a composite liner structure combining PA11 polymer matrix with impact modifier and plasticizer additives to achieve both manufacturability and thermal resistance. This composite approach allows the material to maintain processability while achieving the required thermal performance for hydrogen storage tanks.
Solution Approach 2:
The patent modifies the chemical composition parameters of the liner material by incorporating specific ratios of impact modifier (15-50%) and plasticizer (1-3%), which changes the material properties to achieve both thermal resistance and manufacturability. This parameter optimization resolves the contradiction between ease of manufacture and thermal resistance.
2Temperature
If PA6 is used as the liner material, then the thermal resistance improves, but the resistance to cold deteriorates
Solution Approach 1:
The patent changes the base polymer from PA6 to PA11, which fundamentally alters the temperature-performance characteristics. PA11 provides both thermal resistance and cold resistance, eliminating the trade-off present in PA6. The addition of impact modifier further enhances cold resistance while maintaining thermal properties.
Solution Approach 2:
The patent adds impact modifier specifically to improve cold-temperature performance in the liner material. This localized property enhancement addresses the cold resistance issue without compromising the thermal resistance achieved by the PA11 base material.
3Productivity
If the filling speed is increased, then the productivity improves, but the temperature increases causing thermal degradation
Solution Approach 1:
The patent adds plasticizer to the liner composition, which modifies the thermal properties and thermal stability of the material. This allows the liner to withstand higher temperatures generated during fast filling operations, enabling increased productivity without thermal degradation.
Solution Approach 2:
The patent uses a thermoplastic liner that can be manufactured with controlled thickness and properties optimized for fast filling. The liner acts as a sacrificial thermal management component that protects the hydrogen storage system during high-speed filling, allowing productivity improvement.
4Strength
If the viscosity is increased to improve mechanical strength, then the strength improves, but the ease of manufacture deteriorates
Solution Approach 1:
The patent adds plasticizer to the polymer composition, which reduces the viscosity of the molten material during processing. This allows the material to be easily formed and molded despite having high molecular weight and inherent strength, resolving the contradiction between strength and ease of manufacture.
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 structure achieves improved mechanical strength, reduced hydrogen permeability, and increased operating temperature up to 120°C, enabling faster hydrogen filling without significant manufacturing temperature increases.
Implementation Method 1
at least one oligo- or poly-carbodiimide... which has hydrogen barrier properties, good flexibility, and durability at low temperature
Implementation Method 2
a composition consisting of PA11, from 15 to 50% of an impact modifier and from 1 to 3% of plasticizer, or devoid of plasticizer... at least one catalyst
Implementation Method 3
at least one thermal stabilizer... Thermal resistance at 120° C.
Data Source
AI summary
Multi-layer structure intended for storing hydrogen, including, from the inside out, a sealing layer and a composite reinforcing layer, the innermost composite reinforcing layer being wound around the outermost adjacent sealing layer, at least the innermost sealing layer being made of a composition including: a. 20.5 to 99.845% by weight of a polyamide; b. 0.005 to 0.5% by weight of a catalyst; c. 0.05 to 1% by weight of a heat stabilizer; d. 0.1 to 3% by weight of a oligo- or poly-carbodiimide; e. 0 to 1.5% by weight of a plasticiser; f. 0 to less than 15% by weight of a polyolefin; g. 0 to 30% of an additive, and at least one of the composite reinforcing layers of a fibrous material in the form of continuous fibres impregnated with a composition including at least one polymer P2j, j=1 to m, m being the number of reinforcing layers.