Separator Pore Filling During Electrode Assembly Pressing

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Solution Overview

Problem

Existing methods for manufacturing electrode assemblies result in a decrease in porosity of the separator due to pressing, which affects the performance and safety of electrochemical devices.

Innovation Solution

A method involving dissolving a polymer soluble in an electrolytic solution in a solvent, filling the pores of a separator substrate with the polymer solution, pressing a stack with electrodes, discharging the polymer solution, and injecting primary and secondary electrolytic solutions to maintain porosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If pressing force is applied to manufacture electrode assembly, then electrodes and separator are bonded together, but porosity of separator decreases and pores are distorted

Engineering Contradiction:
Improvebonding strengthVSAvoidporosity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The separator is pre-treated by filling its pores with a polymer solution before the pressing process. This preliminary action creates a protective structure within the pores that prevents distortion during subsequent pressing, allowing strong bonding without porosity loss

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A polymer solution acts as an intermediary substance that is introduced into the separator pores before pressing. This intermediary maintains the pore structure integrity during the pressing operation, enabling both strong bonding and preserved porosity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If separator thickness is reduced to improve ionic conductivity, then battery performance increases, but mechanical strength and stability decrease

Engineering Contradiction:
Improveionic conductivityVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention utilizes the porous structure of the separator as a functional feature rather than trying to eliminate it. By carefully controlling pore filling with polymer solution and preventing pore distortion, thin separators maintain both high ionic conductivity through their porous structure and mechanical strength through the stabilized pore configuration

Inventive Principle:
Principle #31Porous materials

3Ease of manufacture

If conventional pressing method is used, then manufacturing process is simple, but porosity decreases leading to reduced battery performance

Engineering Contradiction:
Improveprocess simplicityVSAvoidbattery performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The separator undergoes preliminary treatment by filling pores with polymer solution before the standard pressing process. This additional preliminary step preserves porosity during pressing, maintaining battery performance without significantly complicating the overall manufacturing流程

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the physical-chemical parameters of the separator by introducing polymer solution into the pores before pressing. This parameter change (filling pores with polymer) modifies the separator's properties to resist compression, thereby preserving porosity and battery performance

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 method effectively maintains the porosity of the separator, ensuring consistent performance and safety of the electrochemical device by preventing pore distortion during the assembly process.

Implementation Method 1

filling pores of a separator porous substrate to be used as a separator with the polymer solution

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

injecting a primary electrolytic solution into the stack of step 3) to discharge the polymer solution in the pores of the separator porous substrate to the outside

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4016689B1Electrode assembly manufacturing method, same electrode assembly and electrochemical device comprising same
Publication Date: 2025.09.10 LG ENERGY SOLUTION LTD
  • EP4016689B1 patent drawingFigure 1
  • EP4016689B1 patent drawingFigure 2(a)~2(e)
  • EP4016689B1 patent drawingFigure 3a

AI summary

Disclosed is an electrode assembly manufacturing method, in which, in a step of stacking and pressing electrodes and a separator, pressing is performed in that state in which pores of a separator porous substrate to be used as the separator are filled with a polymer solution. The form or volume of the pores is not changed due to the polymer solution. Consequently, porosity of the separator after manufacture of an electrode assembly is similar to porosity of the separator before stacking. As a result, a battery including the electrode assembly has high ionic conductivity and excellent performance.