Flexible Graphite Composite Polar Plate With Thinness and Rigidity
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Solution Overview
Problem
Existing thin-film polar plates have limitations in blending ratio of conductive carbon, restricting their efficiency and rigidity, which hinders their performance in energy storage applications, particularly in flow batteries, and require enhanced conductivity and controllable thickness for industrial use.
Innovation Solution
A method for fabricating a flexible plastic graphite composite polar plate by ball-milling high-carbon conductive powder, mixing with a thermoplastic/thermosetting resin adhesive, calendering to achieve desired thickness, and removing solvent under controlled temperature and pressure, allowing for adjustable conductive carbon blending ratios and optional use of supporting members for enhanced rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small amount of conductive carbon powder is applied to form film, then the film can be formed, but the blending ratio of conductive carbon is restricted and conductivity is insufficient
Solution Approach 1:
The patent changes the key parameter of conductive carbon powder from conventional graphite to highly oriented pyrolytic graphite (HOPG) with specific crystal orientation. This parameter change enables much higher conductivity at lower blending ratios, resolving the contradiction between conductivity and carbon quantity. The HOPG powder with controlled particle size distribution (D10: 3-5 μm, D50: 6-8 μm, D90: 9-11 μm) and specific surface area (10-20 m²/g) achieves superior conductive network formation.
Solution Approach 2:
The patent creates a composite material system combining HOPG conductive powder with specific polymer matrices. The composite structure leverages the unique properties of HOPG (highly ordered crystalline structure) combined with polymer flexibility, achieving both high conductivity and mechanical integrity. The composite approach allows optimization of the conductive phase distribution and interaction with the matrix material.
2Length of moving object
If thin-film polar plate is fabricated, then the thickness is reduced, but the rigidity is insufficient
Solution Approach 1:
The patent employs composite materials combining thin polymer film with HOPG conductive powder to achieve both thinness and rigidity. The highly oriented crystalline structure of HOPG provides structural reinforcement within the thin matrix, enabling the polar plate to maintain mechanical strength despite reduced thickness. The composite structure allows the thin film to retain sufficient rigidity for practical applications.
Solution Approach 2:
The patent applies local quality enhancement by concentrating HOPG particles in specific regions and orientations within the thin film. The controlled particle size distribution and surface area characteristics create localized conductive and structural reinforcement zones, providing rigidity where needed while maintaining overall thinness. The local optimization of particle arrangement compensates for the reduced thickness.
3Ease of manufacture
If conventional polar plate is processed with runner, then the manufacturing process is complex, but the integrated mold cannot be obtained
Solution Approach 1:
The patent merges the polar plate fabrication process with integrated mold technology, combining multiple manufacturing steps into a single integrated operation. The method integrates mixing, calendering, and forming operations into one continuous process using specialized mold equipment, eliminating the need for separate runner processing and post-manufacturing assembly steps. This merging of operations directly achieves the integrated mold structure.
Solution Approach 2:
The patent extracts and eliminates the complex runner processing step from the conventional manufacturing process. By using direct integrated mold fabrication, the method removes the intermediate runner system that requires separate processing, simplifying the overall manufacturing workflow. The extraction of this complex step achieves the desired integrated mold structure with fewer processing stages.
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 polar plate with improved longitudinal through-transmission volume resistivity, excellent vanadium ion blocking, and increased rigidity, enabling efficient energy storage and large-area industrial production, while breaking the limitations of traditional blending ratios and supporting member dependencies.
Implementation Method 1
the polar plate is excellent in blocking the through-transmission of vanadium ions
Implementation Method 2
the longitudinal through-transmission volume resistivity (proportional resistance to thickness) is greatly improved by adjusting the blending ratio of conductive carbon
Data Source
AI summary
A polar plate is fabricated. The polar plate is flexible and made of a plastic graphite composite. No matter a supporting member is used for calendering or not, a thin polar plate with controllable thickness is fabricated. The polar plate is excellent in blocking the through-transmission of vanadium ions and the limit of blending ratio of conductive carbon is broken through. The longitudinal through-transmission volume resistivity (proportional resistance to thickness) is greatly improved by adjusting the blending ratio of conductive carbon for meeting the demand of conductivity. In the mean time, the present invention strengthens the rigidity required for the thin polar plate while providing large-area polar plate fabrication for industrial use and convenience and provides a cooling and pressing method for patterning a composite polar plate. An integrated mold is thus obtained to replace the conventional polar plate which needs to be processed and prepared with runner.