Extruder-Based Electrode Slurry Preparation for Binder Migration Control

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Solution Overview

Problem

Existing methods for preparing electrode slurry for lithium secondary batteries face challenges in maintaining high solid content while ensuring suitable viscosity for coating, leading to issues like binder migration and process difficulties due to equipment limitations.

Innovation Solution

A method involving the use of an extruder to simultaneously knead and convey raw materials, including an electrode active material, conductive agent, and thickener, with controlled solvent addition to achieve a high solid content and manageable viscosity, allowing for continuous slurry preparation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the solid content in the electrode slurry is increased to suppress binder migration, then electrode quality is improved, but the viscosity increases making conveyance and application difficult

Engineering Contradiction:

Improveelectrode qualityVSAvoidconveyance and application

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent changes the physical state parameter of the thickener from liquid to solid form. This parameter change allows the slurry to maintain high solid content (improving electrode quality) while the solid thickener particles provide viscosity control without excessive thickening, enabling proper conveyance and application properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite slurry system combining solid thickener particles with electrode active material, conductive agent, and binder. This composite approach allows the solid thickener to serve multiple functions: structural support, viscosity control, and binder migration suppression, resolving the contradiction between quality and processability

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If the solid content in the electrode slurry is increased to suppress binder migration, then electrode quality is improved, but the viscosity increases

Engineering Contradiction:

Improveelectrode qualityVSAvoidslurry viscosity

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses solid thickener particles that distribute uniformly throughout the slurry matrix, creating a homogeneous composite material. This homogeneous distribution ensures consistent viscosity control and effective binder migration suppression throughout the entire slurry volume, maintaining composition stability

Inventive Principle:

Principle #33Homogeneity

3Device complexity

If a conventional mixer is used to prepare electrode slurry, then the mixing process is simple, but the preparation is limited by tank capacity and equipment load preventing continuous production

Engineering Contradiction:

Improvemixing processVSAvoidcontinuous preparation

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent replaces the conventional mechanical mixer system with an extruder-based system. The extruder uses screw conveyance and shear mixing mechanisms to achieve both thorough mixing and continuous production capability, resolving the contradiction between simple mixing and continuous manufacturing

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements continuous slurry preparation using an extruder that operates without interruption. The extruder continuously feeds raw materials, mixes them through screw rotation, and outputs prepared slurry without batch interruptions, enabling continuous production while maintaining mixing effectiveness

Inventive Principle:

Principle #20Continuity of useful action

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 enables high-quality electrode coating by suppressing binder migration, reducing drying time and equipment costs, and improving productivity through increased solid content and continuous processing.

Implementation Method 1

a step b) of feeding a solvent into the mixer and kneading the raw materials

Methodology Applied

Scientific EffectMechanical mixing and shearing: Mechanical Force

Implementation Method 2

feeding a solvent into the mixer and kneading the raw materials

Methodology Applied

Scientific EffectDissolution: Solvation

Data Source

PatentEP4576233A1Method for preparation of secondary battery electrode slurry

Publication Date: 2025.06.25 SK ON CO LTD

Figure 1~2

AI summary

According to the present disclosure, there is provided a method for preparing an electrode slurry for a secondary battery, the method including a step a) of feeding raw materials including an electrode active material, a conductive agent, and a thickener into a mixer; and a step b) of feeding a solvent into the mixer and kneading the raw materials, wherein the thickener in the step a) is in a solid state.