Laser Separator Cutting in Battery Lamination to Prevent Bending

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Solution Overview

Problem

The existing lamination process for secondary batteries suffers from defects such as separator bending or pushing off due to physical contact cutting methods, which affect cutting quality and precision.

Innovation Solution

A lamination apparatus and method using a laser cutting unit that cuts the separation sheet without physical contact, adjusting cutting speed based on conveyor distances and speeds, and incorporating a suction unit to remove debris.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a molded knife is used to cut the separation sheet in physical contact, then the cutting process is simple and fast, but defects such as bending or pushing off of the separator occur, reducing cutting quality

Engineering Contradiction:
Improvecutting qualityVSAvoidcutting device complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical cutting system (molded knife in physical contact) with a laser cutting system that uses optical energy to cut the separation sheet without physical contact. This substitution eliminates mechanical pressure and contact forces that cause separator bending and pushing off defects, thereby improving cutting quality while preventing the harmful effects of mechanical cutting

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a laser beam as an intermediary between the cutting source and the separation sheet. The laser beam acts as a non-contact mediator that transfers energy to cut the material without requiring direct mechanical contact, thus avoiding the defects caused by molded knife contact while maintaining cutting effectiveness

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the laser cutting speed is increased to improve productivity, then more separation sheets can be cut per unit time, but the cutting precision and quality may deteriorate

Engineering Contradiction:
Improvecutting speedVSAvoidcutting precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements dynamic adjustment of laser cutting parameters including cutting speed, laser power, and focal position based on real-time conditions. The system can adaptively optimize the cutting speed for each specific situation, allowing high productivity when conditions permit while maintaining cutting precision when quality is prioritized, thus dynamically balancing productivity and precision requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs parameter changes in the laser cutting process, specifically adjusting cutting speed, laser intensity, and beam focus parameters to optimize both productivity and precision. By varying these parameters based on material properties and desired output quality, the system achieves high cutting speeds without sacrificing precision, resolving the contradiction between productivity and manufacturing precision

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

Prevents defects like separator bending, enhances cutting precision, and improves quality by non-contact laser cutting with adjustable speed control and debris removal.

Implementation Method 1

a laser cutting unit, which irradiates laser onto the separation sheet of the radical unit sheet passing through the transfer conveyor so that the separation sheet is cut by irradiation

Methodology Applied
Scientific EffectLaser: Laser

Data Source

PatentEP4184634B1Cutting device and lamination equipment and method for secondary battery comprising same
Publication Date: 2025.11.26 LG ENERGY SOLUTION LTD
  • EP4184634B1 patent drawingFigure 1
  • EP4184634B1 patent drawingFigure 2
  • EP4184634B1 patent drawingFigure 3

AI summary

A lamination apparatus for a secondary battery according to the present invention comprises a lamination device provided with a supply unit, which supplies electrodes disposed by a set gap on a separation sheet, and a bonding unit, which bonds the separation sheet and the electrodes to manufacture a radical unit sheet, and a cutting device which cuts the separation sheet of the radical unit sheet to manufacture a radical unit constituted by a separator and the electrodes. The cutting device comprises a transfer conveyor, which transfers the radical unit sheet, a laser cutting unit, which irradiates laser onto the separation sheet of the radical unit sheet so that the separation sheet is cut to manufacture the radical unit, a discharge conveyor, which transfers the radical unit cut by the laser cutting unit, and an adjusting unit which adjusts a speed for cutting the separation sheet through the laser cutting unit depending on a spaced distance between the transfer conveyor and the discharge conveyor.