Battery Module Weld Inspection Using Eddy Current Sensing

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Solution Overview

Problem

Existing methods for evaluating weld quality in battery modules are labor-intensive, prone to human error, and lack accuracy and uniformity, making it difficult to consistently assess the welding states of battery cells.

Innovation Solution

An apparatus utilizing a sensor assembly with eddy current detection and a controller to automatically inspect welding states by applying eddy currents to battery cell connections, detecting signal changes based on depth, and using cameras for vision inspection to provide accurate and uniform assessments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual inspection methods are used to evaluate weld quality, then labor flexibility is maintained, but inspection accuracy and consistency deteriorate due to human error and labor intensity

Engineering Contradiction:
Improveweld quality inspection accuracyVSAvoidinspection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical inspection with an automated sensor assembly that applies eddy currents to welding parts. The sensor assembly includes multiple sensing parts that can be movably configured to contact different welding locations, automatically detecting weld quality through electrical signals rather than human visual or tactile inspection.

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

Solution Approach 2:

The inspection system performs self-assessment by having the sensor assembly automatically apply eddy currents to the welding parts and detect the resulting signals. The system evaluates its own measurement data through the controller, which determines welding quality based on the detected eddy current signals without requiring external manual evaluation.

Inventive Principle:
Principle #25Self-service

2Reliability

If automated eddy current inspection is implemented, then inspection consistency and accuracy improve, but device complexity increases due to sensor assembly and controller requirements

Engineering Contradiction:
Improveinspection consistencyVSAvoidsensor assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sensor assembly is divided into multiple independent sensing parts, each capable of inspecting different welding locations. This segmentation allows the system to maintain consistent inspection quality across multiple welding points while keeping each individual sensor relatively simple in design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor assembly is designed with sensing parts that can be movably configured to inspect various welding locations on different battery cells. This multi-functional design allows a single sensor assembly to perform multiple inspection tasks, reducing the need for multiple specialized devices and thereby reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Area of stationary object

If multiple sensing parts are used to inspect multiple welding locations, then inspection coverage improves, but device complexity and cost increase

Engineering Contradiction:
Improveinspection coverage areaVSAvoidnumber of sensing parts
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The sensing parts of the sensor assembly are designed to be movable rather than fixed, allowing a single sensor assembly to cover multiple welding locations by repositioning the sensing parts. This dynamic configuration enables comprehensive inspection coverage without requiring a proportional increase in the number of sensors for each welding point.

Inventive Principle:
Principle #15Dynamics

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

The apparatus achieves non-destructive, accurate, and consistent inspection of welding states, reducing labor costs and ensuring reliable quality control in battery modules.

Implementation Method 1

The sensor assembly may be configured to apply eddy current to welding parts between a busbar and leads of battery cells in a battery module, and detect signals based on the applied eddy current. The detected signals depend on depths of the welding parts.

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentEP4585355A1Apparatus for automatically inspecting welding state
Publication Date: 2025.07.16 HYUNDAI MOTOR CO LTD
  • EP4585355A1 patent drawingFigure 1A
  • EP4585355A1 patent drawingFigure 1B
  • EP4585355A1 patent drawingFigure 1C

AI summary

An apparatus for automatically inspecting the welding state of a battery module is configured to inspect welding states of welding parts of a plurality of leads for electrical connection based on a deep penetration inspection using application of eddy current to the welding parts of the leads.