Unit Cell Probe Inspection for Short-Circuit Defect Localization
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Solution Overview
Problem
Existing methods for examining assembled batteries struggle to efficiently identify defects such as short circuits in resin current collectors, electrode sheets, and unit cells, making it difficult to determine which unit cell is defective when a defect is found in a stacked assembly.
Innovation Solution
An examination method involving the use of conductor probes to measure voltage or electric resistance at multiple points on the surfaces of the examination target, determining if any point is out of an allowable range, and a manufacturing method that stacks only defect-free unit cells based on these results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode plate group is pressed before inserting into the electrolytic bath to examine short circuit, then the short circuit defect can be detected, but it becomes difficult to specify which unit cell has the defect
Solution Approach 1:
The examination target is divided into individual unit cells, each examined separately with conductor probes contacting specific points. This segmentation allows defect detection while preserving location information, as each unit cell can be independently identified and measured.
Solution Approach 2:
Conductor probes serve as intermediaries to contact the examination target at multiple points. These probes enable precise measurement of voltage or electric resistance at specific locations without requiring compression of the entire electrode plate group, thus maintaining defect location information.
2Reliability
If a group of unit cells is pressed in the stacking direction to examine each unit cell, then each unit cell can be examined, but the defective unit cell must be replaced from the group
Solution Approach 1:
The examination is performed on unit cells before they are assembled into the final battery structure. By using conductor probes to measure voltage or electric resistance at multiple points on individual unit cells, defects are detected in advance, allowing only合格 unit cells to be stacked, thus improving productivity by avoiding rework.
3Measurement precision
If multiple points on the surface of the examination target are measured to detect defects, then defect detection accuracy is improved, but the examination process becomes more complex
Solution Approach 1:
The conductor probes are designed with multi-functionality, capable of measuring both voltage and electric resistance at multiple points on the examination target. This universal measurement capability improves defect detection accuracy while maintaining a relatively simple examination process, as the same probe system performs multiple measurement functions.
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 allows for easy detection of defects, improving production yield by ensuring only defect-free unit cells are used in assembled battery manufacturing.
Implementation Method 1
bringing conductor probes into contact with surfaces of an examination target to measure voltage or electric resistance at a plurality of points on the surfaces of the examination target
Data Source
AI summary
An examination method includes bringing conductor probes into contact with surfaces of an examination target to measure voltage or electric resistance at points on the surfaces of the examination target, and determining whether or not the voltage or the electric resistance is out of an allowable range at any of the points. The examination target is a resin current collector, an electrode sheet having an active material layer laminated on a resin current collector, a separator-attached electrode sheet in which a separator is combined with an electrode sheet, or a unit cell including one set of a positive electrode resin current collector, a positive electrode active material layer, a separator, a negative electrode active material layer, and a negative electrode resin current collector, which are laminated in order. With the examination method, a defect such as a short circuit can be easily found and production yield can be improved.