Bipolar Plate Composition for Conductivity Without High Molding Viscosity
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Solution Overview
Problem
Current bipolar plates for fuel cells and Redox-Flow batteries face challenges in achieving high thermal conductivity, electrical conductivity, and mechanical properties while being easily processable, with existing compositions often requiring post-treatment and having high viscosity issues during processing.
Innovation Solution
A method involving melt-blending a fluorinated polymer with a first conductive filler, grinding the mixture into powder, and mixing it with a second conductive filler, such as graphite, to create a conductive fluorinated polymer composition that can be easily processed and compression-molded into bipolar plates with enhanced conductivity and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymer/carbon composite compositions are used, then manufacturing cost is reduced and corrosion resistance is improved, but electrical conductivity and thermal conductivity are insufficient
Solution Approach 1:
The patent employs a composite material system comprising PVDF polymer matrix combined with multiple conductive fillers (graphite, carbon black, and/or carbon fibers) to achieve both high electrical conductivity and ease of processing. The synergistic combination of different conductive materials allows the composition to meet conductivity requirements while maintaining processability during compression molding.
2Reliability
If high carbon content is used to improve conductivity, then electrical conductivity increases, but viscosity during processing increases making molding difficult
Solution Approach 1:
The patent optimizes the composition parameters by controlling the total carbon content within 20-80 wt% and specifying particular ranges for each filler type (graphite: 5-50 wt%, carbon black: 5-30 wt%, carbon fibers: 0.1-10 wt%). This parameter optimization ensures sufficient electrical conductivity while preventing excessive viscosity that would hinder compression molding processing.
3Ease of manufacture
If conventional compression molding is used, then manufacturing is simplified, but surface quality is poor requiring post-treatment like sand blasting
Solution Approach 1:
The patent introduces a skin-core structure where the skin layer (5-50 wt% of total composition) has different properties than the core layer. The skin layer is formulated with optimized filler content and distribution to provide a high-quality surface finish directly from compression molding, eliminating the need for post-treatment sand blasting, while the core layer maintains the bulk conductivity requirements.
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 results in bipolar plates with high in-plane and through-plane conductivity, high thermal conductivity, and improved mechanical properties like flexural and compressive strength, eliminating the need for post-treatment processes like sand blasting and facilitating easier processing.
Implementation Method 1
a conductive fluorinated polymer composition... high in-plane and through-plane conductivity... The composition comprises a fluorinated polymer and a conductive filler dispersed in the fluorinated polymer
Implementation Method 2
high thermal conductivity
Data Source
AI summary
The invention relates to a method for producing a composition comprising the steps of: - melt-blending a fluorinated polymer, preferably a polyvinylidene fluoride polymer, with a first conductive filler so as to obtain a conductive fluorinated polymer; - grinding to powder said conductive fluorinated polymer; - mixing the powder of conductive fluorinated polymer with a second conductive filler. The invention also relates to a composition comprising a second conductive filler and particles of conductive fluorinated polymer, wherein the particles of conductive fluorinated polymer comprise a fluorinated polymer matrix in which a first conductive filler is dispersed The invention also relates to a method for producing a bipolar plate and to a bipolar plate.