Electrode Stacking Inspection Using Corner Imaging and Light Feedback

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Solution Overview

Problem

The existing stacking processes for lithium secondary batteries face challenges in ensuring accurate alignment of cathode and anode electrodes, leading to defects such as twisting and reduced yield, particularly during the folding and lamination of unit cells, which affects the battery's performance, safety, and quality.

Innovation Solution

A stacking inspection apparatus equipped with camera units and light irradiation units that photograph and irradiate four corner points of the electrodes or unit cells to determine alignment defects and measure thickness, using sensors to recognize light signals and correct alignment in real time, thereby minimizing manual measurement errors and improving product quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual measurement and alignment adjustment is used during stacking process, then flexibility and ease of operation are maintained, but measurement precision and manufacturing precision deteriorate due to human error and time consumption

Engineering Contradiction:
Improvealignment measurement precisionVSAvoidinspection apparatus complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical measurement methods with an automated optical inspection system. Camera units capture images of electrode plates, and a control unit automatically processes these images to detect alignment defects, substituting human operators and manual measurement tools with an automated vision-based system that provides higher precision without requiring complex manual adjustment mechanisms

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

Solution Approach 2:

The patent uses camera units to create optical copies (images) of the electrode plates and their corner points. By capturing and analyzing these visual copies rather than performing direct physical measurements, the system achieves high measurement precision through image processing algorithms while maintaining a relatively simple apparatus structure

Inventive Principle:
Principle #26Copying

2Productivity

If the number of stacked unit cells is increased to improve productivity, then output increases, but alignment precision deteriorates due to cumulative stacking errors

Engineering Contradiction:
Improvestacking speedVSAvoidstacking alignment precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the inspection apparatus continuously monitors alignment of stacked unit cells and provides real-time detection of deviation amounts. This feedback information enables corrective actions to be taken during the stacking process, preventing cumulative errors from accumulating even as productivity increases through faster stacking rates

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The inspection apparatus performs preliminary detection of alignment status before significant deviations accumulate. By detecting corner point positions and calculating alignment deviations early in the stacking process, the system can identify and correct issues before they propagate through multiple stacked units, maintaining precision across large numbers of stacked cells

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If real-time inspection is implemented during stacking process, then manufacturing precision is improved, but productivity deteriorates due to additional inspection time

Engineering Contradiction:
Improvealignment precisionVSAvoidstacking throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent enables continuous inspection during the stacking process rather than requiring separate inspection stages. The camera units and control unit operate concurrently with stacking operations, continuously capturing images and processing alignment data without interrupting the stacking flow, thereby maintaining both high precision and productivity

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces time-consuming manual measurement and adjustment operations with automated optical inspection and image processing. The rapid capture and digital analysis of corner point positions enable real-time alignment verification without the mechanical delays associated with manual measurement tools, maintaining stacking throughput while improving precision

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

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 apparatus enables real-time detection and correction of alignment defects and thickness deviations, enhancing the quality and yield of lithium secondary batteries by automating the alignment process and reducing errors associated with manual measurements.

Implementation Method 1

light irradiation units that irradiate a light signal to four corner points of the first electrode plate and the second electrode plate as inspection objects

Methodology Applied
Scientific EffectLight signal recognition: Photoelectric Effect

Data Source

PatentEP4123778B1Stacking inspection apparatus for electrode plate or unit cell
Publication Date: 2024.07.03 LG ENERGY SOLUTION LTD
  • EP4123778B1 patent drawingFigure 1
  • EP4123778B1 patent drawingFigure 2
  • EP4123778B1 patent drawingFigure 3

AI summary

The present disclosure provides a stacking inspection apparatus including: camera units that generate an aligned image by photographing four corner points of the outer periphery of the electrode plates or the unit cells at an upper part in a stacking direction of the electrode plates or the unit cells; and light irradiation units that irradiate light signals to four corner of the inspection object, and sensors that recognize the light signal irradiated from the light irradiation units and determine whether or not alignment of the first electrode plate and the second electrode plate is defective.