Battery Cap Assembly Marking for Non-Destructive Crack Inspection

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Solution Overview

Problem

The cap assembly of secondary batteries can fail to seal properly due to improper assembly or cracks during manufacturing, leading to reduced reliability and safety.

Innovation Solution

A cap assembly with a mark and sub-mark on the cap down and vent surfaces, allowing for a non-destructive full inspection, using a vision camera and processor to extract the mark from the image, and inspect the assembly for cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If non-destructive inspection method is used, then product integrity is maintained, but inspection capability is limited

Engineering Contradiction:
Improveproduct integrityVSAvoidcrack detection capability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

A mark is introduced as an intermediary element on the cap down surface. This mark serves as a reference feature that enables the vision system to detect cracks non-destructively by comparing the mark's position and appearance against expected patterns, thereby maintaining product integrity while enhancing inspection capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The inspection system creates a visual copy (image) of the cap assembly surface including the mark, and processes this copy to detect cracks. This allows non-contact inspection that maintains product integrity while enabling comprehensive crack detection through image analysis

Inventive Principle:
Principle #26Copying

2Productivity

If visual inspection with mark is used, then crack detection speed is improved, but device complexity increases

Engineering Contradiction:
Improveinspection speedVSAvoidinspection system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cap assembly itself provides the inspection reference through the mark formed on its surface. This self-service approach eliminates the need for external complex reference systems, enabling fast inspection while minimizing additional device complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The mark provides a distinct visual feature that the vision camera can easily detect and track. By utilizing optical contrast rather than complex mechanical or electronic references, the system achieves high inspection speed with minimal added complexity

Inventive Principle:
Principle #32Color changes

Data Source

PatentEP4672446A1Cap assembly, secondary battery, and secondary battery inspection device
Publication Date: 2025.12.31 SAMSUNG SDI CO LTD
  • EP4672446A1 patent drawingFigure 1
  • EP4672446A1 patent drawingFigure 2
  • EP4672446A1 patent drawingFigure 3

AI summary

A cap assembly (200), a secondary battery (100) including the cap assembly (200), and a secondary battery inspection device (300) for inspecting the secondary battery (100) are disclosed. A cap assembly (200) includes a cap down (230), a vent (220) located on a surface of the cap down (230), and a mark (260) located on another surface of the cap down (230).