Tab-Lead Weld Inspection Using Multi-Point Resistance Measurement
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Solution Overview
Problem
Existing methods for inspecting weld defects between tabs and leads in lithium secondary batteries are inadequate, often causing damage and inaccuracies due to tensile strength measurements.
Innovation Solution
A device and method using a pair of tab and lead probes to measure resistance values between tabs and leads, determining weak-welding based on multiple resistance values to ensure precise and exhaustive inspection without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tensile strength measurement method is used to inspect weld defects, then detection capability is provided, but tabs and leads are damaged causing measurement errors and exhaustive inspection becomes impossible
Solution Approach 1:
The patent replaces the mechanical tensile strength measurement system with an electrical resistance measurement system. By measuring resistance values between probes contact with tabs and leads, the system detects weak-welding without applying mechanical force that would damage the components. This substitution resolves the contradiction by maintaining detection capability while eliminating the harmful mechanical damage.
2Measurement precision
If multiple resistance values are measured using pair of tab probes and pair of lead probes, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the measurement system into segmented components: a pair of tab probes for contacting tabs, a pair of lead probes for contacting leads, and a control unit that processes multiple resistance measurements. By segmenting the measurement into multiple resistance value readings (first resistance value between tab probes, second between tab and lead probes, third between other tab and lead probes), the system achieves high measurement precision while keeping each individual probe simple.
Solution Approach 2:
The control unit serves multiple functions: it controls the application of voltage to different probe combinations, measures multiple resistance values, compares them against reference values, and determines weak-welding conditions. This multi-functionality allows the system to achieve high measurement precision through multiple measurements without proportionally increasing overall device complexity.
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 solution allows for precise and accurate detection of weak-welding without damaging the tabs or leads, achieving exhaustive inspection through resistance measurements.
Implementation Method 1
measuring a first resistance value between the pair of tab probes, a second resistance value between one tab probe and one lead probe, and a third resistance value between the other tab probe and the other lead probe
Data Source
AI summary
A device for inspecting a welded state between a tab, which protrudes from a plurality of electrodes stacked with a separator therebetween, and a lead welded to the tab. The device for inspecting a welded state may include a pair of tab probes, which are in contact with the tab and spaced apart from each other in a width direction of the tab, and a pair of lead probes which are in contact with the lead and spaced apart from each other in a width direction of the lead. Related methods for inspecting the welded state between a tab and a lead thereby are provided.