Fuel Cell Separator Seal Rubber Composition
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Solution Overview
Problem
Existing separator seals for polymer electrolyte fuel cells face challenges in maintaining long-term elasticity, acid resistance, and adhesion to substrates, particularly in acidic environments, which affects their durability and seal performance.
Innovation Solution
A rubber composition comprising organopolysiloxane, silicone resinous copolymer, organohydrogenpolysiloxane, fumed silica, carbon powder, and an addition reaction catalyst is used to create a separator seal with reduced compression set, improved acid resistance, and enhanced adhesion to substrates, ensuring excellent seal performance over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional silicone rubber compositions are used for separator seals, then ease of molding is improved, but long-term elasticity and acid resistance deteriorate
Solution Approach 1:
The patent uses a composite rubber composition containing multiple polysiloxane components (dimethylpolysiloxane, phenylmethylpolysiloxane, methylhydrogenpolysiloxane) combined with specific additives including fumed silica, carbon black, and sulfur. This composite formulation achieves both ease of molding and long-term elasticity while resisting acid degradation in fuel cell environments.
2Ease of manufacture
If addition cure type silicone rubber is used, then molding process is simplified, but adhesion to separator substrate deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the rubber material by incorporating specific polysiloxane types and ratios, along with curing agents and additives, to achieve optimal adhesion properties while maintaining the simplicity of the addition cure molding process.
3Reliability
If rubber composition is optimized for acid resistance, then durability in acidic environment is improved, but compression set increases
Solution Approach 1:
The patent employs a carefully balanced composite formulation combining multiple polysiloxane components with specific ratios of fumed silica and carbon black fillers, along with sulfur curing system, to simultaneously achieve high acid resistance and low compression set for long-term durability in fuel cell separators.
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 proposed solution results in a separator seal with reduced compression set, high strength, ease of molding, and good adhesion to substrates, providing long-term excellent seal performance even in acidic conditions, making it suitable for polymer electrolyte fuel cells.
Implementation Method 1
a rubber composition comprising (A) an organopolysiloxane containing at least two silicon-bonded alkenyl groups in a molecule, (B) a silicone resinous copolymer, (C) an organohydrogenpolysiloxane containing at least three silicon-bonded hydrogen atoms in a molecule, and (F) an addition reaction catalyst
Implementation Method 2
(D) fumed silica having a BET specific surface area of 50 to 400 m2/g, and (E) carbon powder having a BET specific surface area of 30 to 150 m2/g
Data Source
AI summary
A rubber composition comprising (A) an alkenyl-containing organopolysiloxane, (B) a silicone resinous copolymer, (C) an organohydrogenpolysiloxane, (D) fumed silica having a BET specific surface area of 50-400 m2/g, (E) carbon powder having a BET specific surface area of 30-150 m2/g, and (F) an addition reaction catalyst cures into a product which is useful as a separator seal in PEFCs. The rubber has a reduced compression set even in an acidic atmosphere or in contact with LLC, and the rubber itself has strength and good adhesion to separator substrates. The separator provides excellent seal performance over a long term.