Electrode Assembly Pressing That Preserves Separator Porosity

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Solution Overview

Problem

Existing methods for manufacturing electrode assemblies often result in a decrease in porosity of the separator due to pressing forces, which reduces the performance and safety of secondary batteries.

Innovation Solution

The method involves dissolving a polymer soluble in an electrolytic solution in a solvent to create a polymer solution, filling the pores of a separator porous substrate with this solution, forming a stack with the separator and electrodes, injecting a primary electrolytic solution to discharge the polymer solution from the pores, and finally injecting a secondary electrolytic solution.

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 strength between electrodes and separatorVSAvoidporosity of separator

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The separator is pre-filled with a polymer solution before the pressing process. This preliminary action prepares the separator to maintain its pore structure during subsequent pressing, preventing pore distortion and porosity loss while still allowing effective bonding of electrodes and separator.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A polymer solution acts as an intermediary substance that is filled into the separator pores before pressing. This intermediary material supports the separator structure during pressing, preventing pore collapse, and is subsequently removed to restore the original porosity while maintaining bonding strength.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

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

Engineering Contradiction:

Improveionic conductivityVSAvoidcompression resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The invention utilizes the porous structure of the separator and fills it with a polymer solution to enhance mechanical strength without increasing thickness. The polymer solution reinforces the thin separator structure, providing compression resistance while maintaining the thin profile necessary for high ionic conductivity.

Inventive Principle:

Principle #31Porous materials

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 prevents a decrease in porosity of the separator, maintaining high ionic conductivity and improving the performance and lifespan of the electrochemical device.

Implementation Method 1

filling pores of a separator porous substrate 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 to the outside of the stack

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS12334506B2Electrode assembly manufacturing method, electrode assembly, and electrochemical device including the same

Publication Date: 2025.06.17 LG ENERGY SOLUTION LTD

AI summary

Disclosed is an electrode assembly manufacturing method, in which, in a step of stacking and pressing electrodes and a separator, the pressing is performed in that state in which pores of a porous substrate 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.