Battery Module Tab Welding Inspection Using Laser Etching Marks

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Solution Overview

Problem

Existing battery modules face challenges in detecting and addressing laser welding defects due to abnormalities in the laser welding process, which can lead to quality issues such as defective joining and resistance value abnormalities, making it difficult to identify the cause and frequency of these defects.

Innovation Solution

Incorporating laser etching marks with specific patterns on both sides of the laser welding portions, allowing for easy inspection of similarities or differences with pre-designed marks to assess the quality of laser welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If laser welding monitoring or resistance value measurement is used to detect welding defects, then defect detection capability is improved, but the ability to immediately investigate the cause and respond to changes over time deteriorates

Engineering Contradiction:
Improvedefect detection capabilityVSAvoidtime to investigate cause and respond to changes
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by forming laser etching marks on the workpiece before laser welding. These pre-formed marks serve as reference patterns that enable immediate cause investigation when defects occur, eliminating the time delay associated with post-welding analysis. The marks are created in advance so that when a welding defect is detected, operators can immediately compare the etching mark patterns to identify equipment abnormalities or process changes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses copying by creating laser etching marks that replicate specific patterns on the workpiece. These etching marks serve as optical copies or references of the intended welding pattern and quality standards. By comparing the actual welding results against these pre-formed etching mark copies, the system enables rapid identification of deviations and causes without time-consuming investigative procedures.

Inventive Principle:
Principle #26Copying

2Measurement precision

If destructive inspection is performed to inspect laser welding portions, then inspection accuracy is improved, but productivity deteriorates due to frequent line stops

Engineering Contradiction:
Improveinspection accuracyVSAvoidproduction line continuity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces mechanical destructive inspection methods with optical field-based inspection. Laser etching marks create visible optical patterns on the workpiece surface that can be inspected non-destructively using optical systems such as cameras or vision sensors. This substitution eliminates the need to stop the production line for destructive testing, maintaining both high inspection accuracy and continuous productivity.

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

Solution Approach 2:

The patent uses disposable laser etching marks as inexpensive optical indicators that can be quickly inspected and replaced. These etching marks serve as temporary but effective reference patterns for quality inspection. Their low cost and ease of creation allow for frequent inspection without impacting productivity, replacing the need for expensive and time-consuming destructive testing procedures.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If factors affecting laser welding quality are inspected, then welding quality control is improved, but the complexity of the inspection process deteriorates

Engineering Contradiction:
Improvewelding quality controlVSAvoidinspection process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the quality assessment function from complex multi-parameter inspection systems and concentrates it into simple laser etching mark patterns. By forming etching marks that directly reflect welding quality parameters through their visual appearance, the system separates the quality indication function from complex measurement and analysis equipment. This extraction simplifies the inspection process while maintaining reliable quality control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent utilizes visual appearance changes in laser etching marks as indicators of welding quality. The etching marks exhibit distinct visual characteristics such as pattern clarity, edge sharpness, and color variations that directly correlate with welding quality parameters. This visual indication method replaces complex instrumental analysis with simple optical observation, reducing inspection process complexity while ensuring reliable quality control.

Inventive Principle:
Principle #32Color 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

Enables real-time detection of abnormalities in the laser welding process, facilitating quick identification of quality issues and maintaining consistent bonding strength without requiring frequent line stops for inspection.

Implementation Method 1

laser welding may be used for joining various workpieces such as joining between tabs of battery cells, joining between tabs and bus bars, and assembly of a housing

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 2

a laser etching mark formed on at least one of both sides of the laser welding portion on the workpiece

Methodology Applied
Scientific EffectLaser etching: Laser Ablation

Data Source

PatentEP4693694A1Battery module, manufacturing method of battery module, and inspection method of laser welding
Publication Date: 2026.02.11 AESC JAPAN LTD
  • EP4693694A1 patent drawingFigure 1
  • EP4693694A1 patent drawingFigure 2
  • EP4693694A1 patent drawingFigure 3

AI summary

A battery module (10) includes a laser welding portion (200) formed on a positive electrode tab (120), and a left laser etching mark (210) and a right laser etching mark (220) formed on both sides of the laser welding portion (200) on the positive electrode tab (120).