Fuel Cell Seal Member Low-Temperature Elasticity
Solution Overview
Problem
Existing sealing members for fuel cells, particularly those using ethylene-propylene rubber (EPM) and ethylene-propylene-diene rubber (EPDM), face challenges in maintaining sealing properties at extremely low temperatures due to crystallization of the polymer, leading to reduced rubber elasticity and inadequate sealing performance.
Innovation Solution
A sealing member for fuel cells is developed using a rubber composition with a rubber component that includes EPM or EPDM with an ethylene-ethylene diad distribution ratio of at most 29 mol % and a cross-linking agent featuring an organic peroxide, which suppresses polymer crystallization even at low temperatures, ensuring maintained rubber elasticity and improved sealing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EPM or EPDM rubber is used as the sealing member material, then good sealing property is achieved at normal temperature, but rubber elasticity is lost at extremely low temperature due to polymer crystallization
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber material by incorporating specific amounts of plasticizers (5-20 phr) and anti-crystallization agents (3-15 phr) into the EPM/EPDM matrix. This modifies the polymer's crystallization behavior and glass transition temperature, enabling the sealing member to maintain rubber elasticity at extremely low temperatures while preserving sealing effectiveness.
Solution Approach 2:
The patent creates a composite rubber material system combining EPM or EPDM base rubber with plasticizer components and anti-crystallization agent components. This composite formulation synergistically prevents polymer crystallization at low temperatures while maintaining the adhesive and sealing properties of the base rubber, resolving the contradiction between normal-temperature sealing and low-temperature elasticity.
2Reliability
If adhesive components are added to improve sealing, then sealing property is enhanced, but rubber elasticity deteriorates at low temperature
Solution Approach 1:
The patent carefully controls the composition parameters by limiting adhesive component content to 5-20 phr and incorporating plasticizers (5-20 phr) and anti-crystallization agents (3-15 phr). This optimized parameter balance ensures adequate sealing adhesion while preventing excessive stiffening and crystallization at low temperatures, maintaining rubber elasticity stability.
Solution Approach 2:
The patent introduces plasticizers and anti-crystallization agents as intermediary substances between the adhesive components and the rubber matrix. These intermediaries prevent the adhesive components from causing excessive cross-linking and crystallization, thereby preserving rubber elasticity while still achieving effective sealing adhesion.
3Duration of action of stationary object
If cross-linking is increased to improve sealing durability, then sealing property is enhanced, but low-temperature flexibility is reduced
Solution Approach 1:
The patent optimizes the cross-linking parameter by controlling sulfur content (1-5 phr) and incorporating anti-crystallization agents (3-15 phr) that prevent excessive cross-linking density. This balanced approach achieves sufficient sealing durability through moderate cross-linking while preventing the material from becoming too rigid and losing flexibility at extremely low temperatures.
Solution Approach 2:
The patent uses anti-crystallization agents as intermediaries that interfere with the cross-linking process to prevent excessive cross-linking density. These agents act as spacers between cross-linked chains, maintaining adequate chain mobility and flexibility at low temperatures while still providing sufficient cross-linking for sealing durability.
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 solution effectively maintains rubber elasticity and enhances sealing performance at extremely low temperatures, ensuring reliable operation of fuel cells in cold climates by preventing polymer crystallization and maintaining adhesiveness over long periods.
Implementation Method 1
a cross-linking agent featuring an organic peroxide, which suppresses polymer crystallization even at low temperatures
Implementation Method 2
A sealing member for fuel cells is developed using a rubber composition with a rubber component that includes EPM or EPDM with an ethylene-ethylene diad distribution ratio of at most 29 mol % and a cross-linking agent featuring an organic peroxide
Data Source
AI summary
A sealing member to be used for sealing a constituent member of a fuel cell is provided, the sealing member including a cross-linked product of a rubber composition, in which the rubber composition contains the following components (A) and (B). With this, rubber elasticity is maintained without being lost even under extremely low temperature conditions, and in the case where the sealing member is used in a fuel cell sealed body, an excellent sealing property is exhibited. (A) a rubber component including at least one of an ethylene-propylene rubber or ethylene-propylene-diene rubber having a ratio of ethylene-ethylene diad distribution of at most 29 mol %. (B) a cross-linking agent including an organic peroxide.