Battery Tab Welding Inspection Using Multi-Strength Defect Correlation

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Solution Overview

Problem

Existing methods for inspecting welding defects in secondary battery manufacturing are inadequate for detecting all small welding defects, particularly due to reliance on tensile strength measurements alone.

Innovation Solution

A method that involves manufacturing electrode assembly samples, measuring tensile strength, torsional strength, and peeling strength of the welded portions, deriving correlations between these strengths and welding defects, and establishing reference values to determine defect presence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If only tensile strength measurement is used for welding defect inspection, then the inspection process is simple, but small welding defects cannot be detected

Engineering Contradiction:
Improvedetection capabilityVSAvoidinspection complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the welding quality assessment into three distinct strength measurements: tensile strength, torsional strength, and peeling strength. Each measurement targets different aspects of welding quality, allowing comprehensive detection of various defect types while maintaining systematic and manageable inspection procedures for each individual test

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-dimension tensile strength measurement to multi-dimensional assessment by adding torsional strength (rotational dimension) and peeling strength (shear dimension) measurements. This dimensional expansion enables detection of defects that remain undetected in single-dimension testing

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

2Reliability

If multiple strength measurements are performed, then welding defect detection accuracy is improved, but inspection time and complexity increase

Engineering Contradiction:
Improvewelding reliabilityVSAvoidinspection efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent establishes predetermined reference values for tensile strength, torsional strength, and peeling strength before production. These reference values serve as quick comparison benchmarks during inspection, allowing operators to rapidly assess whether measured values indicate defects without requiring complex real-time analysis

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where measured strength values are compared against reference values to determine pass/fail status. This feedback loop provides immediate quality assessment, enabling rapid decision-making and maintaining high inspection efficiency while ensuring reliable defect detection

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4095510B1Welding defect inspection method
Publication Date: 2025.02.19 LG ENERGY SOLUTION LTD
  • EP4095510B1 patent drawingFigure 1
  • EP4095510B1 patent drawingFigure 2
  • EP4095510B1 patent drawingFigure 3

AI summary

The present technology relates to a method of inspecting a welding defect. The method includes: manufacturing an electrode assembly sample by welding an electrode lead on an electrode tab formed on an electrode assembly; measuring a tensile strength, a torsional strength and a peeling strength of a welded portion between the electrode tab and the electrode lead for the electrode assembly sample; deriving correlation between whether there is a welding defect and each of the tensile strength, the torsional strength, and the peeling strength; and deriving a reference value for determining whether there is a welding defect for the tensile strength, the torsional strength, and the peeling strength, respectively.