Battery Weld Resistance Probing for Non-Destructive Weak Weld Detection
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Solution Overview
Problem
Conventional methods for inspecting welding defects in lithium secondary battery electrodes, such as tensile strength measurement, often damage the electrode tab or lead and are not comprehensive, necessitating a more effective detection method for weak weldings.
Innovation Solution
A welding state inspection apparatus that uses resistance measuring probes to determine the resistance value of welded portions by contacting both ends, with a controller comparing the measured value to a threshold resistance value set via statistical analysis, allowing for precise detection of weak weldings without damaging the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tensile strength measurement is used to inspect welding defects, then welding quality can be assessed, but the electrode tab or electrode lead may be damaged
Solution Approach 1:
The patent replaces the mechanical tensile strength measurement system with an electrical resistance measurement system. By measuring the resistance of the welded portion and comparing it to a threshold value, the system can detect weak weldings without applying mechanical force that would damage the electrode components. This substitution of measurement principle directly resolves the contradiction between inspection reliability and component damage.
2Difficulty of detecting and measuring
If tensile strength measurement is used, then welding defects can be detected, but complete enumeration of defects is not possible
Solution Approach 1:
The electrical resistance measurement system enables non-destructive inspection of multiple welded portions sequentially. Unlike tensile strength measurement which destroys the sample, the resistance measurement preserves the component, allowing complete enumeration of all welding defects in the battery assembly without limiting the number of inspections that can be performed.
3Measurement precision
If resistance measuring probe contacts both ends of welded portion, then precise detection of weak weldings is achieved, but measurement complexity increases
Solution Approach 1:
The patent extracts only the essential measurement function - measuring resistance across the welded portion - and implements it through a simple probe system. By focusing on this single critical measurement rather than comprehensive mechanical testing, the system achieves high precision in detecting weak weldings while keeping the device structure relatively simple and easy to integrate into production lines.
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 precise detection of weak weldings with high detection power, measuring resistances up to nanoohm to microohm levels, eliminating the need for separate tensile strength measurement and ensuring complete enumeration of welding defects.
Implementation Method 1
obtain data for deriving a resistance value of the welded portion by allowing a resistance measuring probe to contact the welded portion
Data Source
AI summary
The present invention provides an apparatus for inspecting a welding state in a welded portion for an electronic or mechanical coupling in a lithium secondary battery, the apparatus including: a measuring unit configured to obtain data for deriving a resistance value of the welded portion by allowing a resistance measuring probe to contact the welded portion; and a controller configured to communicate with the measuring unit, determine the resistance value of the welded portion by receiving the data obtained from the measuring unit, and determine whether a weak welding was performed by comparing the determined resistance value with a threshold resistance value, in which the measuring unit is configured to allow the resistance measuring probe to contact one end and the other end of the welded portion.