Roller Coating Metering Films for Uniform Thin Layers

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Solution Overview

Problem

Conventional coating systems face challenges in achieving uniform coating width and require multiple roller pairs to achieve thin layer thicknesses, often leading to uneven material feed and potential roller damage, especially in the production of electrochemical storage devices like lithium-ion batteries.

Innovation Solution

A method and device using a metering unit with adjustable films to introduce a mixture into the gap between rotating rollers, allowing precise control of the nip region and mixture introduction, reducing the number of roller pairs needed and ensuring uniform coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple roller pairs are used to achieve thin layer thickness, then the target film thickness is achieved, but the device complexity and cost increase

Engineering Contradiction:
Improvefilm thicknessVSAvoidnumber of roller pairs
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention introduces material into the gap between rollers at an optimized position before the nip region, allowing the material to be drawn in and compacted more effectively. This preliminary positioning enables achieving target thickness with fewer roller pairs by maximizing the utilization of each roller gap's compaction capability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the parameter of material introduction position relative to the roller gap and nip angle. By optimizing where and how material is fed into the gap, the compaction efficiency is improved, allowing fewer roller pairs to achieve the same thickness reduction

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If material is fed into the gap at conventional positions, then the coating process is simple, but uneven material feed results in uneven coating across the width

Engineering Contradiction:
Improvecoating uniformityVSAvoidmaterial feed system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention applies different feed strategies to different locations across the coating width. By addressing material distribution locally at each position across the width rather than using a uniform feed approach, even coating is achieved without requiring complex overall system redesign

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Material is introduced into the gap at an optimized position before the nip region, allowing proper material distribution and flow establishment before compaction occurs. This preliminary positioning ensures uniform material feed across the width

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If a small initial roller gap is used to achieve low film thickness, then the target thickness is reduced, but excessive material is drawn and compacted leading to roller overload

Engineering Contradiction:
Improvefilm thicknessVSAvoidroller structure
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

Material is introduced into the gap at an optimized position before the nip region rather than directly at the smallest gap. This allows the material to be gradually drawn in and distributed, preventing sudden excessive material intake that would overload the roller structure

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention optimizes the nip angle and material introduction position parameters. By adjusting these parameters, the material draw-in process is controlled to prevent excessive compaction forces that would damage roller surfaces while still achieving the desired thin film thickness

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

Enables uniform coating width and reduces the number of roller pairs required, achieving precise layer thicknesses and minimizing roller damage, while allowing for both single-sided and double-sided coatings.

Implementation Method 1

Depending on the stress conditions within the material and the friction at the interface between the roller surfaces and the material, the transition to the nip region causes the material to be drawn through the rollers

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

Within the nip region, the material is accelerated from a larger gap to the roller's peripheral speed and compacted by the rollers as it moves towards the smallest gap

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

After passing the smallest gap, the material can partially relax elastically, thus undergoing a volume increase and a corresponding increase in layer thickness

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4640320A1Optimized coating process
Publication Date: 2025.10.29 CELLFORCE GROUP GMBH
  • EP4640320A1 patent drawingFigure 1
  • EP4640320A1 patent drawingFigure 2
  • EP4640320A1 patent drawingFigure 3

AI summary

The invention relates to a method for applying at least one liquid and/or powdery and/or granular mixture to at least one substrate, wherein the mixture is introduced into at least one gap area between at least two rotating rollers, wherein the rollers are at least partially covered by at least two films of a metering unit, wherein the mixture is fed into a metering area between the two films of the metering unit and introduced by the at least one metering unit into the gap area between the at least two rollers, wherein the mixture is applied to the at least one substrate after leaving the metering unit and during compression; or after compression by the at least two rollers, or, depending on the embodiment, is arranged as a film on one of the rollers in order to be transferred to a substrate in a subsequent process.Furthermore, the invention relates to a device for coating at least one side of at least one substrate with a mixture.