Electrostatic Polymer Particle Separator for Lithium Battery Adhesion

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Solution Overview

Problem

Conventional methods for preparing separators for lithium secondary batteries require solvents for electrode-adhesion layers, leading to increased costs, handling hazards, and decreased productivity due to the need for drying steps.

Innovation Solution

A method involving electrostatic charging of polymer particles for laser printing onto porous polymer substrates without solvents, forming electrode-adhesion layers with specific patterns and areas to enhance adhesion and prevent excessive resistance, which includes forming a porous coating layer with inorganic particles and fixing with heat and pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a solvent-based polymer slurry is used to form an electrode-adhesion layer on the separator, then the adhesion of the separator with electrodes is improved, but the production cost increases and productivity decreases due to the need for drying steps

Engineering Contradiction:
Improveadhesion of separator with electrodesVSAvoidproduction efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent extracts and eliminates the solvent component from the conventional slurry coating process. Instead of using a polymer slurry dissolved in solvent, the invention directly uses polymer particles that are sintered to form the electrode-adhesion layer. This removes the need for drying steps and eliminates solvent-related productivity losses while maintaining the adhesive function through direct particle-to-substrate bonding.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the physical state and processing parameters of the polymer material. Rather than applying a liquid slurry that requires drying, the invention uses solid polymer particles and applies thermal energy (sintering at 60-180°C) to fuse them directly onto the separator surface. This parameter change transforms the process from wet-coating requiring evaporation to dry-sintering that achieves adhesion through particle fusion.

Inventive Principle:
Principle #35Parameter changes

2Strength

If a solvent-based polymer slurry is used to form an electrode-adhesion layer on the separator, then the adhesion of the separator with electrodes is improved, but the production cost increases due to solvent handling and storage requirements

Engineering Contradiction:
Improveadhesion of separator with electrodesVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the solvent component from the conventional slurry coating process. Instead of using a polymer slurry dissolved in solvent, the invention directly uses polymer particles that are sintered to form the electrode-adhesion layer. This removes the need for drying steps and eliminates solvent-related productivity losses while maintaining the adhesive function through direct particle-to-substrate bonding.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the expensive and hazardous solvent system with inexpensive, non-hazardous polymer particles. The particles serve their purpose (forming the adhesion layer) and are then permanently fixed through sintering, eliminating the need for solvent recovery, storage, and handling infrastructure. This substitution with simpler, cheaper materials directly reduces manufacturing costs.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If a solvent-based polymer slurry is used to form an electrode-adhesion layer on the separator, then the adhesion of the separator with electrodes is improved, but additional costs are incurred due to safety hazards in handling and storage

Engineering Contradiction:
Improveadhesion of separator with electrodesVSAvoidsafety hazards
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the solvent component from the conventional slurry coating process. Instead of using a polymer slurry dissolved in solvent, the invention directly uses polymer particles that are sintered to form the electrode-adhesion layer. This removes the need for drying steps and eliminates solvent-related productivity losses while maintaining the adhesive function through direct particle-to-substrate bonding.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the hazardous solvent environment with an inert, non-flammable environment using solid polymer particles and air or inert gas atmosphere during sintering. This eliminates fire hazards, toxic exposure risks, and environmental regulations associated with organic solvents, creating a inherently safer manufacturing process while achieving the same adhesion function.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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 eliminates the need for solvent drying, reduces costs, and enables efficient production of separators that prevent excessive resistance in lithium secondary batteries, improving their performance and safety.

Implementation Method 1

bringing polymer particles into electric charging to obtain electrically charged polymer particles

Methodology Applied
Scientific EffectElectrostatic charging: Electrostatics

Implementation Method 2

transferring the electrically charged polymer particles on at least one surface of a porous polymer substrate to form an electrode-adhesion layer

Methodology Applied
Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 3

fixing the electrode-adhesion layer with heat and pressure

Methodology Applied
Scientific EffectHeat pressing: Heat Treatment

Data Source

PatentUS10115950B2Method of preparing separator for lithium secondary battery, separator prepared therefrom, and lithium secondary battery comprising the same
Publication Date: 2018.10.30 LG ENERGY SOLUTION LTD

AI summary

The present disclosure provides a method of preparing a separator for a lithium secondary battery, comprising: (S1) bringing polymer particles into electric charging to obtain electrically charged polymer particles; (S2) transferring the electrically charged polymer particles on at least one surface of a porous polymer substrate to form an electrode-adhesion layer whose area ranges from 1 to 30% based on the total area of the porous polymer substrate; and (S3) fixing the electrode-adhesion layer with heat and pressure. In accordance with the present disclosure, an electrode-adhesion layer is applied by using electrostatic charging, more specifically coating polymer particles by way of laser printing, without the addition of a slurry in a solvent, thereby allowing easy handling and storage and needs no drying step of the solvent to provide cost savings effect as well as rapid and efficient preparation of the separator.