Carbon Foam Electrode for Redox Flow Batteries

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Solution Overview

Problem

Conventional carbon foam experiences performance degradation due to carbon fiber breakage and powdering off when subjected to compressive loads, leading to reduced performance in applications like redox flow batteries and other electrochemical devices.

Innovation Solution

The carbon foam is engineered with a higher node portion density and anisotropic fiber orientation to distribute compressive loads uniformly, reducing fiber breakage and powdering off, and is integrated into a membrane electrode assembly with a specific surface area and porosity to enhance electrochemical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon foam is used as an electrode material in redox flow batteries, then electrical conductivity and porosity are improved, but carbon fiber breakage and powdering off occur under compressive loads

Engineering Contradiction:
Improveelectrode stabilityVSAvoidresistance to compressive load
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses carbon fiber nonwoven fabric as a reinforcement material combined with carbon foam to create a composite electrode structure. The carbon fiber nonwoven fabric forms a three-dimensional network that reinforces the carbon foam, preventing carbon fiber breakage and powdering off under compressive loads while maintaining electrical conductivity and porosity required for redox flow battery operation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent divides the electrode into two functional components: carbon foam providing porosity and electrical conductivity, and carbon fiber nonwoven fabric providing mechanical strength. This segmentation allows each material to perform its optimal function without compromising the other, resolving the contradiction between structural integrity and electrochemical performance.

Inventive Principle:
Principle #1Segmentation

2Reliability

If carbon foam is compressed to improve heat insulating performance, then heat insulating properties are enhanced, but carbon fiber breakage and powdering off increase

Engineering Contradiction:
Improveheat insulating performanceVSAvoidcarbon fiber powdering off
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The carbon fiber nonwoven fabric reinforcement creates a composite structure where the carbon fiber network bears the compressive load, allowing the carbon foam to be compressed for improved heat insulating performance without causing carbon fiber breakage and powdering off.

Inventive Principle:
Principle #40Composite materials

3Strength

If carbon fiber nonwoven fabric is used as electrode material, then mechanical strength is improved, but specific surface area is reduced compared to carbon foam

Engineering Contradiction:
Improvemechanical strengthVSAvoidspecific surface area
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The patent merges carbon fiber nonwoven fabric and carbon foam into a composite electrode where the carbon fiber nonwoven fabric provides mechanical strength and the carbon foam provides high specific surface area. The combination allows the electrode to achieve both mechanical strength and high specific surface area, overcoming the limitation of using carbon fiber nonwoven fabric alone.

Inventive Principle:
Principle #5Merging (Combining)

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 modified carbon foam maintains resilience and conductivity, suppressing electrolyte membrane peeling and maintaining high performance even under compressive stress, thus improving the reliability of electrochemical devices.

Implementation Method 1

the carbon foam has an integral structure in which all the fibers are connected

Methodology Applied
Scientific EffectElectrical conductivity: Conduction (electrical)

Implementation Method 2

Carbon foam is a material obtained, for example, by subjecting melamine resin foam (foam) to heat treatment in an inert gas atmosphere for carbonization

Methodology Applied
Scientific EffectCarbonization: Pyrolysis

Data Source

PatentEP3546435B1Carbon foam and membrane electrode composite
Publication Date: 2022.05.11 ASAHI KASEI KOGYO KABUSHIKI KAISHA
  • EP3546435B1 patent drawingFigure 1A~1B
  • EP3546435B1 patent drawingFigure 2
  • EP3546435B1 patent drawingFigure 3

AI summary

Provided is a carbon foam and a membrane electrode assembly having linear portions and node portions joining the linear portions; and a carbon foam and a membrane electrode assembly having linear portions and node portions joining the linear portions, where the carbon content is 51 mass% or more, and the mean deviation of coefficient of friction by the Kawabata evaluation system method is 0.006 or less.