Polyelectrolyte Ink for Uniform Electrolyte Layer Formation

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Solution Overview

Problem

Conventional electrolyte inks used in electrochemical cell manufacturing fail to form a homogeneous, pin-hole-free electrolyte layer with uniform thickness, which can lead to short circuits and other manufacturing issues.

Innovation Solution

A polyelectrolyte composition is developed using a solvent mixture where water is a minority component, incorporating quaternary cationic polyelectrolytes like PDADMAC and diols such as propylene glycol, with controlled water content and rheology characteristics suitable for printing, allowing for the formation of a stable electrolyte layer between electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional water-based polyelectrolyte inks are used for printing electrolyte layers, then the manufacturing process is simple, but the electrolyte layer contains pin-holes and has non-uniform thickness leading to short circuits

Engineering Contradiction:
Improveelectrolyte layer integrityVSAvoidelectrolyte layer uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the solvent composition parameters by reducing water content from the conventional majority component to a minority component (0-40 wt%), and introduces diol solvents (ethylene glycol, propylene glycol) as main solvent components. This parameter change in solvent composition eliminates pin-hole formation and achieves uniform electrolyte layer thickness while maintaining printability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite solvent system combining diols (ethylene glycol, propylene glycol) with reduced water content, rather than using pure water or single solvents. This composite approach provides optimal balance between viscosity for printing, evaporation rate, and electrolyte layer formation quality, eliminating the pin-hole defect

Inventive Principle:
Principle #40Composite materials

2Reliability

If the electrolyte layer is made to connect electrodes electrolytically, then ionic conductivity is achieved, but electronic separation must be maintained to prevent short circuits

Engineering Contradiction:
Improveelectrolyte connectivityVSAvoidshort circuit risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical and chemical parameters of the electrolyte layer by controlling solvent composition (diol-water ratio), polyelectrolyte concentration (5-20 wt%), and layer thickness through printing parameters. These parameter changes ensure the layer is thick enough for electronic isolation but thin and uniform enough for ionic connectivity, eliminating pin-holes that would cause short circuits

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the printed film has homogenous thickness, then manufacturing quality is improved, but the composition must be precisely controlled

Engineering Contradiction:
Improvefilm thickness uniformityVSAvoidcomposition control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent establishes specific parameter ranges for composition control: diol 60-100 wt%, water 0-40 wt%, polyelectrolyte 5-20 wt%. Within these ranges, the formulation provides optimal viscosity for printing and uniform evaporation characteristics, achieving homogenous film thickness without requiring overly complex control systems

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses homogenous diol-water-polyelectrolyte mixtures as ink compositions, ensuring uniform viscosity and evaporation rate throughout the printed material. This homogeneity in composition translates directly to uniform film thickness after printing and drying, simplifying the manufacturing process

Inventive Principle:
Principle #33Homogeneity

4Adaptability or versatility

If the electrolyte ink is over-printable or coatable, then subsequent electrode layer application is enabled, but the first layer must have specific surface properties

Engineering Contradiction:
Improveover-printabilityVSAvoidsurface quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent adjusts solvent composition parameters (diol-water ratio) and polyelectrolyte concentration to achieve optimal surface properties: controlled viscosity for level spreading, appropriate surface tension for adhesion, and uniform evaporation rate. These parameter changes create a smooth, defect-free surface that accepts subsequent electrode layer deposition

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

The composition enables the creation of a smooth, pin-hole-free electrolyte layer with uniform thickness, enhancing the stability and performance of electrochemical cells by improving ion mobility and connectivity between electrodes.

Implementation Method 1

removing water either before or after step II), wherein the water removal is achieved preferably through evaporation, solvent exchanging or freeze-drying

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

removing water either before or after step II), wherein the water removal is achieved preferably through evaporation, solvent exchanging or freeze-drying

Methodology Applied
Scientific EffectSolvent exchange: Liquid-Liquid Extraction

Implementation Method 3

the electrolyte should form a layer electronically separating the bottom electrode from the top electrode... the printed film should preferably or ideally have a homogenous thickness

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 4

removing water either before or after step II), wherein the water removal is achieved preferably through evaporation, solvent exchanging or freeze-drying

Methodology Applied
Scientific EffectFreeze-drying: Freeze Drying

Data Source

PatentEP3522283B1Polyelectrolyte composition and a process for its making
Publication Date: 2020.05.27 RISE ACREO AB
  • EP3522283B1 patent drawingFigure 1
  • EP3522283B1 patent drawingFigure 2
  • EP3522283B1 patent drawingFigure 3

AI summary

The present invention relates to a polyelectrolyte composition, to a method of producing the composition, to an electrochemical cell comprising the polyelectrolyte composition and to use of the polyelectrolyte composition.