Conductive Composite Bipolar Plate for Fuel Cells
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Solution Overview
Problem
Conventional bipolar plates in proton exchange membrane fuel cells lack sufficient flexural strength, which is a critical limitation for their performance and durability.
Innovation Solution
An electrically conductive composite is developed, comprising 20-40 weight percent of a block copolymer of rubber and vinyl ester resin, combined with 60-80 weight percent of conductive fillers such as graphite powder, carbon fiber, or carbon nanotubes, to enhance mechanical strength and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional bipolar plates (dense carbon or metal plates) are used, then conductivity and chemical corrosion resistance are achieved, but flexural strength is insufficient
Solution Approach 1:
The patent employs a composite material system consisting of thermoplastic resin (30-70 wt%), conductive filler (20-40 wt%), and hydrophilic agent (0.1-5 wt%). This composite structure combines the mechanical strength of thermoplastic resin with the conductivity of carbon-based fillers (graphite powder, carbon fiber, or carbon nanotubes) and the proton conductivity of hydrophilic agents, thereby achieving both high flexural strength and adequate durability simultaneously
2Ease of manufacture
If dense carbon plates are used, then conductivity is improved, but manufacturing cost increases due to expensive raw materials and additional flow trench filling process
Solution Approach 1:
The patent utilizes the melting and solidification properties of thermoplastic resin by controlling processing temperature (above melting point during molding, then cooling below melting point). This parameter change enables the resin to flow and fill all pores and cavities during molding, automatically achieving hermetic sealing without requiring additional post-processing filling steps, thereby reducing manufacturing cost while maintaining hermeticity
3Ease of manufacture
If composite material is used to reduce cost, then manufacturing cost decreases and flow trenches can be directly formed, but flexural strength is insufficient
Solution Approach 1:
The patent employs a composite material system consisting of thermoplastic resin (30-70 wt%), conductive filler (20-40 wt%), and hydrophilic agent (0.1-5 wt%). This composite structure combines the mechanical strength of thermoplastic resin with the conductivity of carbon-based fillers (graphite powder, carbon fiber, or carbon nanotubes) and the proton conductivity of hydrophilic agents, thereby achieving both high flexural strength and adequate durability simultaneously
Solution Approach 2:
The patent utilizes the melting and solidification properties of thermoplastic resin by controlling processing temperature (above melting point during molding, then cooling below melting point). This parameter change enables the resin to flow and fill all pores and cavities during molding, automatically achieving hermetic sealing without requiring additional post-processing filling steps, thereby reducing manufacturing cost while maintaining hermeticity
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 composite bipolar plates exhibit improved flexural strength of 4000 to 7000 psi, tensile strength of 3000 to 5000 psi, and maintain conductivity, corrosion resistance, and hermeticity, making them suitable for high-performance fuel cell applications with reduced manufacturing costs.
Implementation Method 1
a block copolymer which is a copolymer of a rubber and a vinyl ester resin
Implementation Method 2
60-80 weight percent of conductive fillers such as graphite powder, carbon fiber, or carbon nanotubes
Data Source
AI summary
The invention provides an electrically conductive composite having high conductivity, hermeticity, high mechanical strength, low surface roughness, lightweight, and thin profile. The composite comprises a rubber modified with vinyl ester resin. After curing in mold, the composite may serve as a bipolar plate in a fuel cell. For example, the bipolar plate is combined with a membrane electrode assembly (MEA) to form a proton exchange membrane fuel cell (PEMFC).