Battery Tab-Lead Inspection Using Eddy Current Impedance

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Solution Overview

Problem

Existing methods for inspecting the tab-lead connecting portion of secondary batteries are inefficient and inaccurate, leading to potential electrical instability and separation issues, and there is a need for a rapid and non-destructive method to assess the physical and electrical connection conditions.

Innovation Solution

A method using an eddy current sensor to induce and measure impedance in the battery's metal portions, applying a discriminant function to analyze the condition of the tab-lead connection, utilizing multiple AC currents at different frequencies to accurately judge the connection state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional inspection methods are used for tab-lead connecting portion, then inspection can be performed, but inspection speed is slow and accuracy is insufficient

Engineering Contradiction:
Improveinspection accuracyVSAvoidinspection speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces traditional mechanical contact-based inspection methods with eddy current sensing technology. The eddy current sensor non-contactively detects the tab-lead connecting portion by generating electromagnetic fields, eliminating mechanical contact while achieving both high-speed and high-precision inspection capabilities suitable for automated production lines.

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

Solution Approach 2:

The patent utilizes changes in eddy current sensor output impedance as the inspection parameter. By monitoring impedance variations caused by defects in the tab-lead connection, the system achieves rapid and accurate detection without mechanical contact, resolving the contradiction between inspection speed and accuracy.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If eddy current sensor is used to inspect metal portion, then inspection speed increases, but measurement accuracy may be affected by complex impedance factors

Engineering Contradiction:
Improveinspection speedVSAvoidmeasurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces a signal processing system as an intermediary between the eddy current sensor and the final inspection result. The system processes the complex impedance output by calculating resistance and reactance components, and compares them against reference values to accurately determine the presence of defects, thereby maintaining measurement accuracy while achieving high-speed inspection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where the eddy current sensor output is continuously monitored, processed, and compared against predetermined reference values. This feedback loop enables real-time accurate measurement by adjusting for variations in the complex impedance signal, maintaining precision while enabling rapid inspection.

Inventive Principle:
Principle #23Feedback

3Reliability

If non-destructive inspection method is applied, then battery integrity is maintained, but inspection capability for physical and electrical problems needs to be enhanced

Engineering Contradiction:
Improvebattery integrityVSAvoiddetection capability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces destructive mechanical inspection methods with non-contact eddy current sensing. The eddy current sensor detects both physical defects (such as cracks or discontinuities) and electrical problems (such as poor connections) in the tab-lead connecting portion without damaging the battery, thereby maintaining battery integrity while enhancing comprehensive detection capability.

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

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 quick and precise inspection of the battery's metal portions without damage, suitable for mass production lines, ensuring reliable electrical connections.

Implementation Method 1

an eddy current induction step of inputting an input current that is an AC current into a transmission coil and irradiating a primary magnetic field generated in the transmission coil to a metal portion of the battery to induce an eddy current in the metal portion of the battery

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Implementation Method 2

an output voltage measurement step of inputting a secondary magnetic field generated by the eddy current generated in the eddy current induction step into a receiving coil and measuring an induced electromotive force in the receiving coil generated by the secondary magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4113113B1Big data-based battery inspection method
Publication Date: 2026.03.18 LG ENERGY SOLUTION LTD
  • EP4113113B1 patent drawingFigure 1
  • EP4113113B1 patent drawingFigure 2
  • EP4113113B1 patent drawingFigure 3

AI summary

The present invention relates to a big data-based battery inspection method. Specifically, the present invention is for providing a big data-based battery inspection method which applies information on a metal part of a battery measured by an eddy current sensor to a discrimination function so as to quickly inspect the state of the metal part.