Graphite-Polymer Bipolar Laminate for Low-Permeability Conductivity

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Solution Overview

Problem

Existing bipolar layers in electrochemical devices face challenges in achieving good electronic conductivity while being impermeable to ions and gases, and are often costly and require elaborate processing.

Innovation Solution

A laminated material composed of alternating layers of expanded graphite foil and polymeric film, processed through heat and pressure to seal the porosity of the graphite foil, resulting in a cost-effective, electrically conductive, and low-permeability laminate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metals are used for bipolar layers, then electrical conductivity and strength are improved, but corrosion resistance deteriorates

Engineering Contradiction:

Improveelectrical conductivityVSAvoidcorrosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite structure combining graphite (providing electrical conductivity and corrosion resistance) with polymer coatings (providing additional protection and sealing). This composite approach allows the material to achieve both high electrical conductivity and excellent corrosion resistance, resolving the contradiction between these two properties.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If expanded graphite is used for bipolar layers, then corrosion resistance and ease of manufacture are improved, but permeability deteriorates

Engineering Contradiction:

Improveease of formationVSAvoidpermeability

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies a polymer coating layer over the expanded graphite foil, creating a thin film barrier that seals the porous structure. This coating acts as a flexible shell that maintains the ease of manufacture advantage of expanded graphite while blocking permeability to ions and gases, thus resolving the contradiction.

Inventive Principle:

Principle #30Flexible shells and thin films

3Object-affected harmful factors

If resin impregnation is used to reduce permeability, then permeability is improved, but manufacturing cost and complexity increase

Engineering Contradiction:

ImprovepermeabilityVSAvoidprocessing complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Instead of using complex resin impregnation processes, the patent employs a simple polymer coating applied as a thin film layer over the expanded graphite. This coating method achieves low permeability without requiring the complex vacuum impregnation and curing processes associated with resin treatment, thus reducing manufacturing complexity while maintaining effectiveness.

Inventive Principle:

Principle #30Flexible shells and thin films

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 laminate achieves lower specific resistivity and reduced permeability, enabling cost-effective production of bipolar layers for electrochemical devices.

Implementation Method 1

subjected to heat and pressure to seal porosity and enhance conductivity

Methodology Applied

Scientific EffectHeat and pressure sealing:

Implementation Method 2

When the expanded graphite flakes are then recompressed, the individual flakes of the expanded graphite interlock with one another resulting in a flexible foil

Methodology Applied

Scientific EffectMechanical interlocking:

Implementation Method 3

A laminated material composed of alternating layers of expanded graphite foil and polymeric film... demonstrating improved electrical conductivity

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12617193B2Electrically conductive corrosion resistant bodies of low permeability

Publication Date: 2026.05.05 ELEKTRODA LLC

AI summary

An electrically conductive, corrosion resistant carbon-based sheet with low permeability to liquids and gases and a method for its manufacture. A multilayer laminate consisting of polymeric film laminated with expanded graphite foil is produced by compressing the layers under heated conditions. The resulting laminate can be used to produce a current collector or a bipolar layer in an electrochemical cell.