Fuel Cell Separator Conductivity and Flexibility via Composite Resin
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fuel cell separators lack sufficient electrical conductivity, flexibility, and bending strength, and require improved hydrophilicity to efficiently manage water discharge during reactions.
Innovation Solution
A method involving a composite material with 15 to 40 parts by mass of fibrous resin and 85 to 60 parts by mass of conductive material, primarily graphite particles and carbon fibers, is used to create a separator with enhanced electrical conductivity, flexibility, and bending strength, featuring a composite sheet preparation, formed body preparation, and heating and compression steps to achieve a hydrophilic surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graphite particles are dispersed in thermoplastic resin to form separator, then the separator can be formed in desired shape and provide basic conductivity, but the electrical conductivity is insufficient and connection among graphite particles is inadequate
Solution Approach 1:
The patent uses a composite material system consisting of thermoplastic resin, graphite particles, and epoxy resin. This composite approach allows the separator to achieve both adequate electrical conductivity and mechanical strength by combining materials with complementary properties, resolving the contradiction between conductivity and structural integrity.
Solution Approach 2:
Epoxy resin serves as an intermediary material that enhances the connection between graphite particles. The epoxy resin fills gaps and creates conductive pathways between dispersed graphite particles, improving overall electrical conductivity without requiring direct particle-to-particle contact.
2Strength
If conventional separator materials are used, then the separator can provide basic mechanical strength, but the bending strength and flexibility are insufficient for thin and lightweight designs
Solution Approach 1:
The patent modifies the material composition parameters by incorporating epoxy resin in specific proportions (34-40 weight%) alongside thermoplastic resin and conductive materials. This parameter optimization achieves enhanced bending strength while maintaining flexibility, enabling thinner and lighter separator designs.
Solution Approach 2:
The combination of thermoplastic resin, epoxy resin, and conductive materials creates a composite structure that provides both mechanical strength and flexibility. The epoxy resin forms a rigid network that enhances bending strength, while the thermoplastic component maintains flexibility, allowing thin lightweight construction.
3Ease of operation
If the separator surface is made hydrophobic to repel water, then water vapor transport may be improved, but the ability to immediately discharge generated water through flow paths is reduced
Solution Approach 1:
The separator exhibits different surface properties at different locations. The surface is designed to be hydrophilic to promote water discharge, while the bulk material provides structural integrity and conductivity. This local differentiation allows efficient water management without compromising overall separator performance.
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 produces a fuel cell separator with improved electrical conductivity, flexibility, bending strength, and hydrophilicity, effectively managing water discharge and maintaining performance under high temperatures and humidity.
Implementation Method 1
a conductive material having higher electrical conductivity than the resin and having forms of particles and fibers, wherein the conductive material mainly comprises graphite particles and carbon fibers
Implementation Method 2
a heating and compression step of stacking, heating and compressing the conductive material formed body and the composite sheet
Implementation Method 3
a heating and compression step of stacking, heating and compressing the conductive material formed body and the composite sheet
Data Source
Figure 1~(1B)
Figure 2
Figure 3(a)~3(d)
AI summary
[Problem] To provide: a separator for fuel cells, which exhibits excellent electrical conductivity, flexibility and bending strength, while having a separator surface that has excellent hydrophilicity; and a method for producing the separator for fuel cells. [Solution] The present invention relates to: a separator 1 for fuel cells, which comprises 15-40 parts by mass of a resin 5 and 85-60 parts by mass of conductive materials 6,7 that have higher electrical conductivities than the resin 5, while having the forms of particles and fibers, and wherein the conductive materials 6,7 mainly comprise graphite particles 7 and carbon fibers 6 so that the graphite particles 7 are comprised therein in a larger amount than the carbon fibers 6 in terms of mass ratio; and a method for producing the separator 1 for fuel cells.