Electrode Sheet Slitting With NG Marks for Selective Scrap Removal

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Solution Overview

Problem

Existing secondary battery manufacturing processes face challenges in improving yield and productivity due to the inability to effectively identify and scrap defective electrode sheets during the slitting process.

Innovation Solution

A secondary battery manufacturing method and slitting device that utilize NG marks, such as 2D barcodes, to inspect and mark defects on electrode sheets, allowing for selective scrapping of defective portions and improving the manufacturing process efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire electrode sheet is scrapped when a defect is detected, then product quality is ensured, but productivity and yield decrease due to excessive material waste

Engineering Contradiction:
Improveproduct qualityVSAvoidyield
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The electrode sheet is divided into multiple coated lanes, and defects are localized to specific lanes rather than affecting the entire sheet. The slitting device separates the electrode sheet into individual lanes, allowing defective lanes to be identified and removed independently while preserving non-defective lanes for production use.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Defective coated lanes are extracted and removed from the electrode sheet through the slitting process. The NG mark sensor identifies defective lanes, and the slitting device physically separates and removes only these defective portions, leaving the remaining non-defective lanes intact for continued production.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If continuous production is maintained without inspection, then productivity is high, but defective products are manufactured reducing yield

Engineering Contradiction:
Improveproduction speedVSAvoidyield
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Inspection and marking of defective lanes are performed in advance during the coating process before the electrode sheet proceeds to subsequent manufacturing steps. The NG mark sensor detects defects and applies NG marks to defective lanes early, enabling downstream processes to identify and handle defective portions without interrupting the overall production flow.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

NG marks serve as an intermediary indicator system that bridges the inspection process and the slitting/separation process. The marks provide visual or machine-readable information about defective lanes, allowing the slitting device to automatically identify and separate defective portions without requiring continuous human inspection or stopping the production line.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If manual inspection and identification of defects is used, then defect detection is possible, but labor intensity increases and inspection precision decreases

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidinspection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Manual inspection is replaced with an automated NG mark sensor system that uses optical or imaging technology to detect defects on the electrode sheet. The sensor automatically identifies defective coated lanes and applies NG marks, eliminating the need for manual visual inspection while improving detection consistency and accuracy.

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

Solution Approach 2:

The inspection system creates a digital or visual record of the electrode sheet surface through imaging, allowing defect analysis without direct physical contact or manual examination. The NG mark sensor captures images or optical signals of the coated lanes and processes this information to identify defects, replacing manual inspection with an automated optical copying and analysis system.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP4645517A1Slitting device, secondary battery manufacturing system comprising same, and method for manufacturing secondary battery
Publication Date: 2025.11.05 LG ENERGY SOLUTION LTD
  • EP4645517A1 patent drawingFigure 1~2
  • EP4645517A1 patent drawingFigure 3
  • EP4645517A1 patent drawingFigure 4~5

AI summary

According to exemplary embodiments, provided is a method for providing a secondary battery. The method comprises: a step for applying an electrode slurry so that a plurality of holding part lanes are formed on a first electrode sheet unwound from a first electrode roll a step for inspecting the first electrode sheet to collect inspection data; a step for forming an NG mark on the first electrode sheet on the basis of the inspection data, and winding the first electrode sheet into a second electrode roll, wherein the NG mark indicates the horizontal position of a defect on the first electrode sheet.