Optical Weld Monitoring for Non-Destructive Defect Detection

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Solution Overview

Problem

Existing welding defect inspection methods for secondary batteries are time-consuming and often destructive, limiting their applicability to sampling.

Innovation Solution

An optical device comprising an infrared detection unit, visible light detection unit, and spectroscopic unit to detect heat, plasma, and wavelength-specific luminosity during welding, combined with a machine learning model trained on reference optical measurement data to identify defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional welding inspection methods are used, then measurement precision can be achieved, but inspection time is excessive and the process is destructive

Engineering Contradiction:
Improvewelding defect detection accuracyVSAvoidinspection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces conventional mechanical/electrical inspection methods with an optical-based detection system. The optical device uses infrared sensors to detect heat radiation, visible light sensors to detect plasma, and spectroscopic sensors to analyze wavelength-specific luminosity from the weldment during laser welding, enabling non-contact, real-time defect inspection that is both rapid and non-destructive

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

Solution Approach 2:

The patent performs welding defect inspection during the welding process itself rather than after completion. By monitoring optical characteristics (heat, plasma, luminosity) in real-time during welding, the system can identify defects as they occur, enabling immediate detection without requiring separate post-welding inspection steps

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If conventional welding inspection methods are used, then measurement precision can be achieved, but the inspection process destroys the target object

Engineering Contradiction:
Improvewelding defect detection accuracyVSAvoiddestructive inspection
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces destructive mechanical testing or electrical inspection methods with non-contact optical sensing. The optical device detects welding defects by analyzing optical radiation (infrared heat radiation, visible plasma light, and spectral luminosity) emitted during the welding process, completely avoiding physical contact or damage to the weldment

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

Solution Approach 2:

The patent uses optical radiation as an intermediary carrier to transfer information about the weldment's internal state and defect conditions. By detecting heat radiation, plasma light, and spectral characteristics of the welding process, the system indirectly observes weld quality without directly interacting with or damaging the target object

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multi-parameter optical detection is implemented, then welding defect detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvewelding defect detection accuracyVSAvoidoptical detection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the optical detection system into three specialized sensor units, each targeting a specific optical parameter: infrared sensors for heat radiation detection, visible light sensors for plasma detection, and spectroscopic sensors for wavelength-specific luminosity analysis. This segmentation allows each component to be optimized for its specific function while working together as an integrated system

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optical device is designed as a multi-functional detection system that simultaneously monitors multiple welding parameters (heat, plasma, luminosity) using a unified platform. The system processes multiple optical signals concurrently to comprehensively assess weld quality, making the device adaptable to various welding conditions and defect types

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables rapid, non-destructive welding defect inspection by accurately determining defect types without damaging the inspection target, improving the performance of the trained model by clearly representing welding characteristics.

Implementation Method 1

an infrared detection unit that detects heat generated at a weldment during welding

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

a visible light detection unit that detects plasma generated at the weldment

Methodology Applied
Scientific EffectPlasma emission detection: Plasma

Implementation Method 3

a spectroscopic unit that detects wavelength-specific luminosity at the weldment

Methodology Applied
Scientific EffectSpectroscopic analysis: Absorption Spectroscopy

Data Source

PatentEP4592020A1Optical device and method for training machine learning model for welding defect inspection
Publication Date: 2025.07.30 SAMSUNG SDI CO LTD
  • EP4592020A1 patent drawingFigure 1~2
  • EP4592020A1 patent drawingFigure 3~4
  • EP4592020A1 patent drawingFigure 5~6

AI summary

An optical device may include an infrared detection unit that detects heat generated at a weldment during welding, a visible light detection unit that detects plasma generated at the weldment and a spectroscopic unit that detects wavelength-specific luminosity at the weldment, wherein the optical device determines an occurrence of welding defects at the weldment based on the detected heat, the detected plasma, and/or the detected wavelength-specific luminosity of the weldment.