Bipolar Ion Exchange Sheet with Metal Hydroxide Nanoparticles

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Solution Overview

Problem

Bipolar ion exchange sheets exhibit low ion selectivity and high membrane resistance, leading to reduced water decomposition efficiency and the need for high voltage for regeneration, which can cause heat generation.

Innovation Solution

A bipolar ion exchange sheet comprising a cation exchange membrane with a cation exchange coating layer and an anion exchange membrane with an anion exchange coating layer, both including metal hydroxide nanoparticles, and a water decomposition catalyst layer between them, bonded with an ion exchange membrane of different polarity, to enhance ion adsorption and desorption characteristics without chemical use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional method of producing bipolar ion exchange sheet using cation or anion exchange resin powders and polyethylene binders is used, then ion adsorption characteristics are good, but ion selectivity is low and membrane resistance is high, reducing water decomposition efficiency

Engineering Contradiction:
Improveion adsorption characteristicsVSAvoidwater decomposition efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent uses composite materials by combining cation exchange resin powder with polyethylene binder in specific ratios (60-80 wt% resin, 20-40 wt% binder) to create a bipolar ion exchange sheet that achieves both good ion adsorption characteristics and improved water decomposition efficiency through optimized material composition

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes physical parameters including sheet thickness (10-100 μm), resin particle size (1-100 μm), and binder content to optimize performance. By controlling these parameters, the sheet achieves low membrane resistance and high ion selectivity while maintaining good ion adsorption characteristics

Inventive Principle:
Principle #35Parameter changes

2Ease of repair

If high level of voltage is applied to regenerate bipolar ion exchange sheet, then regeneration is achieved, but heat is generated

Engineering Contradiction:
Improveregeneration capabilityVSAvoidheat generation
Core Design Contradiction:
Ease of repairVSTemperature

Solution Approach 1:

The patent changes the electrical parameter threshold by optimizing membrane resistance through controlled composition and thickness, enabling regeneration at lower voltages (reduced by 20-40% compared to conventional sheets) and thereby reducing heat generation during the regeneration process

Inventive Principle:
Principle #35Parameter changes

3Reliability

If ion exchange membrane with high membrane resistance is used, then ion selectivity is maintained, but water decomposition efficiency is reduced at constant potential

Engineering Contradiction:
Improveion selectivityVSAvoidwater decomposition efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent optimizes the thickness parameter to 10-100 μm and resin particle size to 1-100 μm to achieve a balance between ion selectivity and membrane resistance. This parameter optimization allows water decomposition to proceed efficiently at constant potential while maintaining high ion selectivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates local quality differences by forming a bipolar structure with distinct cation exchange and anion exchange regions, each optimized for its specific function. The cation exchange layer prioritizes ion selectivity while the anion exchange layer is optimized for low resistance, achieving overall system efficiency

Inventive Principle:
Principle #3Local quality

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 solution achieves low membrane resistance, increased water decomposition efficiency, and improved regeneration efficiency at lower voltages, with enhanced mechanical and thermal stability, and increased ion exchange capacity.

Implementation Method 1

improve water decomposition characteristics by adsorbing or desorbing ions in an electrical manner without using chemicals

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

water molecules are decomposed into hydrogen ions (H+

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 3

An ion exchange membrane, a separation membrane, uses the momentum of mass transfer as electromotive force in separating ionic materials

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 4

anions cannot penetrate through the ion exchange membrane through the Donnan exclusion of cation exchange membranes

Methodology Applied
Scientific EffectDonnan exclusion:

Data Source

PatentEP3222349B1Bipolar ion exchange sheet and manufacturing method therefor
Publication Date: 2022.03.23 COWAY CO LTD
  • EP3222349B1 patent drawingFigure 2
  • EP3222349B1 patent drawingFigure 4(a)~4(d)
  • EP3222349B1 patent drawingFigure 5~6

AI summary

The present invention relates to a bipolar ion exchange sheet and a manufacturing method therefor, the bipolar ion exchange sheet comprising: a cation exchange film comprising a cation adsorption sheet and a cation exchange coating layer formed on one side of the cation adsorption sheet; and an anion exchange film comprising an anion adsorption sheet and an anion exchange coating layer formed on one side of the anion adsorption sheet, wherein the cation exchange film and the anion exchange film are bonded so that the cation exchange coating layer and the anion exchange coating layer face each other.