Spreader Roller Stretching for Wrinkle-Free Electrode Foil Measurement

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Solution Overview

Problem

The manufacturing of electrode foils for batteries often results in uneven stretching and tensions due to calendaring, which can lead to measurement inaccuracies and reliability issues.

Innovation Solution

A system comprising a bendable spreader roller and a pivot-mounted frame, which stretches the electrode foil locally in a direction perpendicular to the conveying direction, reducing or eliminating tensions and ensuring a smoother surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If pressure is applied to the electrode foil during calendaring to compact the coating portion, then the coating density and uniformity are improved, but tensions and wrinkles appear in the electrode foil due to uneven stretching

Engineering Contradiction:
Improvecoating uniformityVSAvoidfoil tension stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The electrode foil is stretched in the width direction before the calendaring process using a stretching device. This preliminary stretching action prepares the foil to accommodate the subsequent compression during calendaring without developing excessive tensions or wrinkles, thereby maintaining both coating uniformity and foil stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical state and dimensions of the electrode foil by applying controlled stretching in the width direction before calendaring. This parameter change (increasing width through stretching) allows the foil to better withstand the compression forces during calendaring, preventing tension formation while achieving compact coating.

Inventive Principle:
Principle #35Parameter changes

2Shape

If high pressure is applied during calendaring to eliminate wrinkles, then the surface smoothness is improved, but the tensions in the electrode foil increase and residual stress remains

Engineering Contradiction:
Improvesurface smoothnessVSAvoidresidual stress
Core Design Contradiction:
ShapeVSStress or pressure

Solution Approach 1:

The electrode foil undergoes preliminary stretching in the width direction before calendaring. This pre-stretching creates initial tension that counteracts the compressive forces during calendaring, allowing the foil to maintain surface smoothness without accumulating excessive residual stress or tensions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The stretching device applies a preliminary anti-action by stretching the foil in the width direction opposite to the compressive forces that will be applied during calendaring. This counterbalancing action prevents the formation of tensions and wrinkles while reducing residual stress.

Inventive Principle:
Principle #9Preliminary anti-action

3Reliability

If the electrode foil is stretched in the conveying direction to reduce tensions, then the foil uniformity is improved, but the thickness distribution becomes uneven and coating quality deteriorates

Engineering Contradiction:
Improvefoil uniformityVSAvoidthickness distribution
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

Instead of stretching the electrode foil in the conveying direction (which would affect thickness distribution), the patent applies asymmetric stretching in the width direction perpendicular to the conveying direction. This asymmetric approach targets tension reduction without compromising the thickness uniformity achieved during calendaring in the conveying direction.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent shifts the stretching action from the conveying direction (length dimension) to the width direction (transverse dimension). This dimensional change allows tension reduction to occur in one dimension without negatively affecting the thickness distribution and coating quality in another dimension.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If conventional stretching methods are used to eliminate tensions, then some tension reduction is achieved, but the residual stress remains large and wrinkles cannot be fully eliminated

Engineering Contradiction:
Improvetension reductionVSAvoidresidual stress
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The stretching device applies preliminary stretching in the width direction before calendaring, creating initial tension that systematically counteracts compressive forces. This preliminary action more effectively eliminates both wrinkles and residual stress compared to conventional post-calendaring stretching methods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the stretching parameters by applying force in the width direction rather than the conveying direction, and by stretching before calendaring rather than after. This parameter change enables more effective tension and stress reduction while maintaining coating quality.

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 system effectively reduces tensions in the electrode foil, resulting in a smoother surface and more accurate measurements during the manufacturing process.

Implementation Method 1

the spreader roller is bendable and configured to stretch the electrode foil at least in a local area of the electrode foil in a direction perpendicular to the conveying direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4571865A1System for preparing an electrode foil in a manufacturing line for a measurement step
Publication Date: 2025.06.18 CUSTOMCELLS HOLDING GMBH
  • EP4571865A1 patent drawingFigure 1~3
  • EP4571865A1 patent drawingFigure 4~5
  • EP4571865A1 patent drawingFigure 6

AI summary

The invention relates to a system for preparing an electrode foil in a manufacturing line for a measurement step, wherein the electrode foil moves in a conveying direction, the system comprising a spreader roller capable of guiding an electrode foil, wherein the spreader roller is bendable and configured to stretch the electrode foil at least in a local area of the electrode foil in a direction perpendicular to the conveying direction, and a pivot mounted frame, wherein the spreader roller is mounted on the frame, wherein by pivoting the frame, the spreader roller is contactable to the electrode foil.