Fuel Cell Separator Hydrophilicity Maintenance
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Solution Overview
Problem
Existing methods for forming fuel cell separators fail to maintain high hydrophilicity over time, leading to decreased performance and stability in fuel cell power generation due to contamination and loss of hydrophilic properties.
Innovation Solution
A method involving a composition of graphite powder, epoxy resin, and phenolic resin, where the surface is subjected to roughening treatment followed by infrared laser irradiation and hydrophilizing treatment, enhancing both hydrophilicity and electrical conductivity while maintaining these properties for a long duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface of a fuel cell separator is hydrophilized by treatment with fluorine gas or SO3 gas, then the initial hydrophilicity is improved (contact angle 20°), but the hydrophilicity is not maintained after long-term use (contact angle rises to 35° after 2000 hours)
Solution Approach 1:
The separator surface is pre-treated with a silane coupling agent containing hydrophilic groups before final hydrophilization treatment. This preliminary action creates a stable hydrophilic layer that prevents subsequent contamination and maintains hydrophilicity over long periods, resolving the contradiction between initial hydrophilicity and long-term durability.
Solution Approach 2:
The invention uses a composite surface treatment combining silane coupling agent coating with subsequent hydrophilization treatment (plasma or chemical). This composite approach creates a multi-layer surface structure that provides both initial hydrophilicity and long-term stability, preventing the contact angle increase observed with single-treatment methods.
2Reliability
If the surface is roughened and subjected to atmospheric-pressure plasma treatment to improve hydrophilicity (contact angle 20°), then initial hydrophilicity is improved, but the contact angle rises to 67° after one month of atmospheric storage
Solution Approach 1:
The silane coupling agent is applied to the roughened surface before plasma treatment. This preliminary coating creates a protective layer that prevents binder component bleed-out and mold release agent contamination, maintaining the hydrophilic properties created by plasma treatment over extended periods.
Solution Approach 2:
The invention converts the harmful effect of binder component bleed-out and mold release agent contamination into a benefit by using the silane coupling agent as a barrier layer. This layer prevents contaminants from reaching the hydrophilic surface, thereby maintaining hydrophilicity where previous methods failed.
3Object-affected harmful factors
If infrared laser irradiation is used to remove binder component at the separator surface, then contamination due to bleed-out is prevented, but the initial contact angle is 30° or more indicating inadequate hydrophilicity
Solution Approach 1:
After laser irradiation removes the binder component, the invention immediately applies a silane coupling agent containing hydrophilic groups to the cleaned surface. This preliminary action prevents contamination while simultaneously restoring and enhancing hydrophilicity, achieving both goals that neither method could accomplish alone.
Solution Approach 2:
The invention changes the surface chemical parameters by introducing silane coupling agents with specific hydrophilic functional groups after laser cleaning. This parameter change transforms the clean but hydrophobic laser-treated surface into a hydrophilic surface that maintains both cleanliness and water affinity.
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 method results in a fuel cell separator with high hydrophilicity that maintains water drainage efficiency and stable power generation over extended periods, ensuring consistent performance.
Implementation Method 1
subjecting the surface of an article molded from a composition containing a graphite powder, an epoxy resin and a phenolic resin to roughening treatment, followed by infrared laser irradiation treatment
Implementation Method 2
infrared laser irradiation treatment and, additionally, hydrophilizing treatment
Implementation Method 3
followed by infrared laser irradiation treatment and, additionally, hydrophilizing treatment, has a high hydrophilicity and maintains that hydrophilicity for a long time
Data Source
AI summary
A fuel cell separator obtained by: roughening the surface of a compact formed by molding a composition containing graphite powder, an epoxy resin, and a phenol resin; treating the compact with infrared laser irradiation; and then performing a hydrophilizing treatment, wherein a fuel cell separator is provided having the characteristics that (1) the initial static contact angle is no greater than 20°, and (2) after manufacture, the static contact angle after being stored in atmospheric air for 3000 hours is no greater than 30°. This fuel cell separator has high hydrophilicity, allowing water generated during the electrical generation of the fuel cell to be easily discharged, and the hydrophilicity is maintained over a long period of time.