Unit Cell Separator Solvent Softening to Preserve Thickness

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Solution Overview

Problem

The existing method for manufacturing unit cells, which involves heating and pressing to release the cured binder in the separator, can lead to unintended reduction in the thickness of the separator, affecting stability and performance.

Innovation Solution

The method involves dipping the separator in a solvent to soften the binder, rather than relying on heat to release the cured binder, thereby preventing thickness reduction. This process includes a solvent dipping step, a drying step, and a collection step to manage the solvent effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heat and pressure are applied to release the cured binder in the separator, then the binder is effectively released and electrodes are bonded, but the separator thickness is unintentionally reduced affecting stability and performance

Engineering Contradiction:

Improvebinder release effectivenessVSAvoidseparator thickness

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameter of binder release from thermal (heat-based) to chemical (solvent-based). Instead of applying heat to soften and release the cured binder, a solvent is applied that chemically dissolves or swells the binder, allowing electrode bonding without the thermal degradation that causes separator thickness reduction. This parameter substitution resolves the contradiction by achieving binder release effectiveness through a different mechanism that does not harm separator dimensions.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If heat is applied to soften and release the cured binder, then the bonding process is enabled, but the separator undergoes thermal degradation and thickness reduction

Engineering Contradiction:

Improvebonding process enablementVSAvoidthermal degradation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the thermal system (heat application) with a chemical system (solvent application). The heat-based mechanism for softening binder is substituted with a solvent-based chemical mechanism that achieves the same bonding enablement without the harmful thermal effects. This substitution eliminates thermal degradation while maintaining the ease of manufacture through a simpler, more controlled chemical process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the separator is dipped in solvent to soften the binder, then thickness reduction is prevented, but additional process steps are required

Engineering Contradiction:

Improveseparator thickness maintenanceVSAvoidprocess steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a solvent as an intermediary substance that facilitates the binder release process. The solvent acts as a mediator between the electrode assembly and the binder, enabling controlled softening and release without direct thermal exposure to the separator. While this adds a process step, the intermediary approach provides precise control over the binder release, ensuring separator thickness maintenance through a controlled chemical interaction rather than uncontrolled thermal exposure.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively prevents the reduction in separator thickness, enhancing the stability and performance of the unit cells by maintaining the separator's integrity during the manufacturing process.

Implementation Method 1

a solvent dipping step (S10) of dipping the first separator in a solvent to soften a cured binder

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 2

the negative electrode and the positive electrode are bonded at surfaces contacting the first separator

Methodology Applied

Scientific EffectMechanical pressure: Compression

Data Source

PatentUS12266753B2Apparatus for manufacturing unit cell

Publication Date: 2025.04.01 LG ENERGY SOLUTION LTD

AI summary

A method of manufacturing a unit cell having a negative electrode, a separator, and a positive electrode are stacked and placed between guide rollers. One of the positive electrode and the negative electrode. The separator is coated with a binder, and the separator is dipped in a solvent to soften a cured binder before the separator is put between the guide rollers. An apparatus for manufacturing a unit cell includes a reservoir in which at least two or more transfer rollers that rotate while the separator passes therethrough are mounted, and a solvent is stored at a predetermined level; and a chamber into which the separator passing through a reservoir is put together with the positive electrode and the negative electrode. Guide rollers are disposed so that the negative electrode and the positive electrode move to both surfaces of the separator, respectively.