Reinforced Separator Impregnation for Redox Flow Battery Crossover

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Solution Overview

Problem

Existing reinforced separators in redox flow batteries face challenges with low selective ion permeability and high electrolyte liquid crossover due to inadequate impregnation of ionic polymers into porous supports, which affects battery performance and durability.

Innovation Solution

A method is developed to enhance the impregnation rate of ionic polymers into porous supports by pretreating the supports with a first solution containing an ionic polymer and ethanol, followed by impregnation with a second solution of higher ionic polymer concentration, thereby increasing the affinity and reducing electrolyte liquid crossover.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a reinforced separator is used in redox flow batteries, then mechanical strength is improved, but selective ion permeability deteriorates due to inadequate impregnation of ionic polymers into porous supports

Engineering Contradiction:

Improvemechanical strengthVSAvoidselective ion permeability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies preliminary action by performing a pretreatment step before the main impregnation process. The porous support is first treated with a solution containing ionic polymer and ethanol to activate the surface and improve subsequent impregnation efficiency, thereby achieving both mechanical strength and selective ion permeability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs parameter changes by optimizing the concentration of ionic polymer in the impregnation solution and controlling the ethanol content to modify the hydrophobicity of the porous support. This enables enhanced impregnation rate while maintaining the structural integrity and ion permeability of the reinforced separator

Inventive Principle:

Principle #35Parameter changes

2Reliability

If ionic polymer concentration in impregnation solution is increased, then selective ion permeability is improved, but manufacturing complexity increases due to multi-step pretreatment process

Engineering Contradiction:

Improveselective ion permeabilityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the pretreatment and impregnation steps into a integrated process where the same solution containing ionic polymer and ethanol serves both to activate the porous support surface and to provide the ionic polymer for impregnation, thereby reducing manufacturing complexity while maintaining high selective ion permeability

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If impregnation rate of ionic polymer is increased, then crossover phenomenon of electrolyte liquid is prevented, but manufacturing time is extended due to multi-stage impregnation process

Engineering Contradiction:

Improveprevention of electrolyte liquid crossoverVSAvoidmanufacturing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The pretreatment step with ionic polymer and ethanol solution prepares the porous support in advance to enhance its affinity for ionic polymer, enabling faster and more efficient impregnation that achieves high impregnation rate and prevents electrolyte liquid crossover in reduced manufacturing time

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

By optimizing the ethanol concentration and ionic polymer content in the impregnation solution, the patent accelerates the impregnation kinetics while ensuring thorough penetration of ionic polymer into the porous support, thereby preventing electrolyte crossover without excessively extending manufacturing time

Inventive Principle:

Principle #35Parameter changes

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

This approach significantly enhances the impregnation rate of ionic polymers, improving the mechanical strength and selective ion permeability of the reinforced separator, reducing electrolyte liquid crossover, and maintaining efficient battery performance over time.

Implementation Method 1

enhancing an impregnation rate of a hydrophilic ionic polymer into a porous support exhibiting hydrophobicity

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

enhancing affinity between a hydrophobic porous support and a hydrophilic ionic polymer

Methodology Applied

Scientific EffectHydrophobic-hydrophilic interaction: Hydrophobe

Data Source

PatentUS11309564B2Method for manufacturing reinforced separator, reinforced separator manufactured using the same and redox flow battery

Publication Date: 2022.04.19 LG CHEM LTD

AI summary

A method for manufacturing a reinforced separator including pretreating a porous support using a first solution including a first ionic polymer and ethanol; and impregnating a second solution including a second ionic polymer and a solvent into the pretreated porous support, wherein a concentration of the first ionic polymer in the first solution is lower than a concentration of the second ionic polymer in the second solution, a reinforced separator manufactured using the same, and a redox flow battery.