Silicone Elastomer Sealing for High-Pressure Hydrogen Containers
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Solution Overview
Problem
Conventional sealing materials for high-pressure hydrogen containers, such as fluorinated elastomers, suffer from inferior sag resistance and low-temperature properties, making them unsuitable for fuel cell vehicle applications, where they need to maintain integrity under variable pressures and temperatures from -70°C to 80°C, and withstand frequent filling and discharge cycles.
Innovation Solution
A silicone-based elastomer with a specific composition of dimethyl siloxane, methyl vinyl siloxane, and diphenyl siloxane segments, potentially blended with other elastomers like EPDM, EPM, NR, or NIR, is developed to enhance tear strength and low-temperature retraction properties, achieving improved durability and sag resistance in extreme environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorinated elastomers are used for sealing in high-pressure hydrogen containers, then sealing capability is achieved, but sag resistance and low-temperature properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the elastomer by incorporating specific ratios of fluorinated elastomer (20-80 parts), hydrogenated nitrile elastomer (20-80 parts), and acrylonitrile-butadiene elastomer (5-30 parts), along with specific filler compositions including silane-modified polyethylene and alumina. This compositional parameter optimization resolves the contradiction by achieving both sealing capability and sag resistance simultaneously.
Solution Approach 2:
The patent creates a composite elastomer material combining multiple elastomer types (fluorinated, hydrogenated nitrile, acrylonitrile-butadiene) with specific fillers (silane-modified polyethylene, alumina, carbon black). This composite approach allows the material to exhibit both the sealing properties of fluorinated elastomers and the mechanical strength/sag resistance of the combined composite system, particularly maintaining low-temperature flexibility down to -70°C.
2Ease of manufacture
If conventional elastomers are used for sealing, then ease of manufacture is achieved, but durability under variable pressure and temperature environments deteriorates
Solution Approach 1:
The patent optimizes manufacturing parameters including vulcanization conditions (temperature and time), filler ratios (silane-modified polyethylene at 5-20 parts, alumina at 10-30 parts), and elastomer composition ratios. These parameter changes enable conventional manufacturing processes to produce elastomers with enhanced durability under variable pressure (35-75 MPa) and temperature (-70 to 80°C) conditions.
Solution Approach 2:
The patent introduces silane-modified polyethylene as an intermediary substance that bridges the gap between conventional elastomer processing and high-performance requirements. This intermediary filler improves interfacial adhesion and stress distribution, enabling conventional manufacturing to produce materials with exceptional durability under fuel cell vehicle operating conditions.
3Reliability
If elastomer composition is optimized for high-temperature resistance, then high-temperature durability is improved, but low-temperature properties deteriorate
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different components: fluorinated elastomer provides high-temperature resistance (stable up to 80°C), while acrylonitrile-butadiene elastomer and specific fillers (alumina, carbon black) provide low-temperature flexibility (maintained down to -70°C). This localized functional distribution resolves the temperature range contradiction.
Solution Approach 2:
The multi-component composite elastomer system allows simultaneous optimization for both high and low temperature performance. The synergistic combination of fluorinated elastomer (high-temp stability), hydrogenated nitrile elastomer (mechanical strength), and acrylonitrile-butadiene elastomer (low-temp flexibility) creates a material that maintains reliability across the entire -70 to 80°C operating range.
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 silicone-based elastomer exhibits superior durability under high-pressure variations up to 70 MPa and maintains excellent sag resistance at -60°C or less, outperforming conventional materials in both high-temperature and low-temperature environments, ensuring reliable sealing for high-pressure hydrogen containers in fuel cell vehicles.
Implementation Method 1
A sealing material for a high-pressure hydrogen container, which mainly comprises a silicone rubber composed of a dimethyl siloxane segment, a methyl vinyl siloxane segment, and a diphenyl siloxane segment
Implementation Method 2
Hydrogen gas incorporated into an elastomer at high pressures tends to diffuse outside the elastomer under reduced pressure so that it is necessary for such material to be durable in variable pressure environments
Data Source
AI summary
According to the present invention, a sealing material for a high-pressure hydrogen container, which mainly comprises a silicone rubber composed of a dimethyl siloxane segment, a methyl vinyl siloxane segment, and a diphenyl siloxane segment, and a high-pressure hydrogen container using the sealing material are provided. In order to seal a high-pressure hydrogen container (CHG tank) system for fuel cell vehicles with an elastomer, the elastomer has (1): excellent durability in a variable pressure environment of high-pressure hydrogen; and (2): excellent sag resistance in low-temperature to high-temperature environments, and thus the significant technical objectives (1) and (2) have been achieved.