Eddy Current Sensor Inline Weld Quality Control

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Solution Overview

Problem

Current methods for inspecting welded joints in battery production are either time-consuming, expensive, or destructive, leading to increased scrap rates and economic inefficiencies due to the inability to perform non-destructive, inline quality control of weld seams.

Innovation Solution

The implementation of an eddy current sensor system guided over the weld seams to generate data for quality control, using artificial intelligence to interpret the eddy current data and adjust the welding process in real-time, allowing for non-destructive, inline characterization and optimization of weld quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If X-ray analysis or computed tomography is used to examine welded joints, then measurement precision is improved, but loss of time and cost increase, making inline inspection impossible

Engineering Contradiction:
Improvewelded joint examination accuracyVSAvoidinspection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces complex mechanical imaging systems (X-ray, CT) with a simplified electrical measurement system using eddy current sensors. This substitution maintains measurement capability while dramatically reducing inspection time and enabling inline quality control during battery element production.

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

Solution Approach 2:

The patent employs inexpensive eddy current sensors that can be quickly positioned and removed, replacing expensive, time-consuming imaging equipment. The simple sensor design allows for rapid, repeated use during production without the overhead of complex imaging systems.

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

2Measurement precision

If ultrasonic measurement is used to examine welded joints, then measurement precision is improved, but the need for coupling medium makes inline use essentially not possible

Engineering Contradiction:
Improvewelded joint examination accuracyVSAvoidinline inspection feasibility
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces ultrasonic measurement (requiring coupling media and complex setup) with electrical eddy current measurement. This substitution eliminates the need for coupling media and simplifies the inspection process, enabling direct inline use during production.

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

3Ease of operation

If electrical resistance measurements are used to examine welded joints, then ease of operation is improved, but measurement precision and informative value regarding mechanical resilience are insufficient

Engineering Contradiction:
Improveinspection simplicityVSAvoidweld seam quality assessment accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transitions from simple electrical resistance measurement to eddy current measurement, changing the electrical parameter being measured. Eddy currents provide more sensitive detection of weld quality and better correlation with mechanical resilience while maintaining operational simplicity.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If pull-off tests are used to evaluate mechanical stability of welded joints, then measurement precision is improved, but the welded connection is destroyed, increasing scrap parts

Engineering Contradiction:
Improvemechanical stability assessment accuracyVSAvoidscrap battery cells
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent replaces destructive mechanical pull-off tests with non-destructive eddy current measurement. This substitution preserves the welded connection and battery cell while providing sufficient information about weld quality through electrical characteristic analysis.

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

Solution Approach 2:

The patent creates an electrical signature or model of the weld quality through eddy current measurement, serving as a non-destructive copy or proxy for mechanical strength assessment. This allows quality evaluation without physically destroying the test specimen.

Inventive Principle:
Principle #26Copying

5Reliability

If safety factors are increased in weld seam design to ensure quality, then reliability is improved, but manufacturing cost increases and productivity decreases

Engineering Contradiction:
Improveweld seam quality assuranceVSAvoidbattery element production efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements real-time feedback through eddy current measurement during production. This allows immediate detection and correction of weld quality issues, enabling tight process control without excessive safety factors, thereby maintaining reliability while improving productivity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs quality measurement during the production process itself rather than as a subsequent check. This preliminary inline inspection allows immediate process adjustment, preventing defective products and reducing the need for oversized safety factors.

Inventive Principle:
Principle #10Preliminary action

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

This approach enables cost-effective, automated, and reliable quality control of weld seams, reducing scrap rates and improving the uniformity and quality of battery elements by providing real-time feedback and process adjustments during production.

Implementation Method 1

A first eddy current sensor is guided at least once over the at least one welded joint, with a data set of the detected measurement signals being generated as eddy current data by the first eddy current sensor

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP4005725A1Method for producing a battery element
Publication Date: 2022.06.01 POWERCO SE
  • EP4005725A1 patent drawingFigure 1~2
  • EP4005725A1 patent drawingFigure 3
  • EP4005725A1 patent drawing

AI summary

Method for manufacturing a battery element (2), wherein at least two battery components (4, 6) are joined in a welding process by means of at least one weld joint (18), wherein at least one first eddy current sensor (20) is provided for generating and detecting eddy currents in the weld joint (18), which is passed over the at least one weld joint (18) at least once, wherein the first eddy current sensor (20) generates eddy current data (26) when passed over the weld joint (18), wherein a first output variable (28) characterizing the weld joint (18) is generated on the basis of the eddy current data (26) and a trained artificial intelligence, wherein a quality control is carried out on the basis of the first output variable (28), and wherein the welding process is controlled and/or regulated on the basis of a result of the quality control.