Wrinkle Detection Device Using Slit Light Gradient Analysis

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Solution Overview

Problem

Existing wrinkle detection methods rely on size criteria, which are inadequate for identifying precursor wrinkles or actual wrinkles based on their gradient, leading to potential overlooking of defects in secondary battery separators.

Innovation Solution

A wrinkle detection device and method that utilize slit light projection and imaging to detect wrinkles by analyzing the gradient of the separator surface, identifying steep gradients through pixel elevation comparisons and determining wrinkle candidates based on predetermined threshold values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If wrinkle detection is performed using size criteria (length, width), then the detection method is simple, but the detection precision is insufficient to identify precursor wrinkles or actual wrinkles

Engineering Contradiction:
Improvewrinkle detection precisionVSAvoiddetection method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the detection parameter from size (length, width) to gradient (rate of change of elevation). The determination unit calculates the gradient of elevation changes in the wrinkle detection direction and compares it against threshold values to identify wrinkles. This parameter transformation enables detection of precursor wrinkles and actual wrinkles that were previously undetectable using size-based criteria alone.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If visual determination of wrinkles is performed, then the detection method is simple, but the reliability is low due to risk of overlooking wrinkles and increased cycle time

Engineering Contradiction:
Improvewrinkle detection reliabilityVSAvoiddetection cycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the manual visual determination method with an automated optical measurement system. A light source illuminates the separator surface, a sensor detects reflected light intensity variations, and a determination unit automatically processes the data to identify wrinkles based on gradient calculations. This substitution eliminates human error and accelerates the detection process.

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

Solution Approach 2:

The system performs self-detection and self-judgment of wrinkles through automated data processing. The determination unit automatically calculates gradients, compares them against predetermined thresholds, and identifies wrinkle locations without requiring external manual intervention, enabling continuous rapid inspection.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If laser beam reflection intensity is used for wrinkle detection, then the detection capability is improved, but the measurement precision is still insufficient for gradient-based identification

Engineering Contradiction:
Improvegradient measurement precisionVSAvoidgradient detection difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the separator surface into multiple measurement points along the wrinkle detection direction. The determination unit calculates elevation changes between adjacent segments and derives gradient information from these segmented measurements. This segmentation approach transforms the difficult task of direct gradient measurement into a series of simpler elevation difference calculations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces elevation change as an intermediary parameter between the raw reflected light intensity and the final gradient calculation. The system first measures elevation changes at multiple points, then uses these elevation data as intermediaries to calculate gradients. This intermediary step simplifies the measurement process and improves precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Effectively identifies wrinkles and their precursors by detecting steep gradients on the separator surface, improving battery quality evaluation and reducing the risk of overlooking defects, thus enabling more accurate identification and removal of defective battery components.

Implementation Method 1

a laser beam is emitted onto the surface of the separator; and wrinkles are detected in accordance with the intensity of light reflected off the surface

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2696165B8Wrinkle detection device and wrinkle detection method
Publication Date: 2019.10.30 ENVISION AESC JAPAN LTD

AI summary

A wrinkle detection device (100) includes: a light projector (110) which, while moving relative to a layered body (40) formed by stacking electrodes (50) and separators (60), projects slit light onto an outermost one of the separators (60); a camera (120) which shoots a shape of the slit light on the separator (60); and a control unit (130) which calculates a gradient of the separator (60) on the basis of the shot shape of the slit light, and determines the existence of a wrinkle on the basis of the calculated gradient.