Asymmetric Eddy Current Probe for Sealed Battery Cell Crack Detection
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Solution Overview
Problem
There is a need for a non-destructive method to detect cracks in stack-folding type battery cells, as visual inspection is insufficient and existing methods cannot detect cracks inside sealed battery cells.
Innovation Solution
An eddy current sensor system is developed, comprising a probe with a transmission unit and a receiving unit. The transmission unit has a larger cross-sectional area than the receiving unit, allowing for the induction of eddy currents in the battery cell and the sensing of signal changes by the receiving coil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection is used to detect cracks in battery cells, then the inspection process is simple and fast, but it cannot detect cracks inside sealed battery cells
Solution Approach 1:
The patent replaces visual inspection (optical/mechanical system) with eddy current sensing (electromagnetic system). The transmitting coil generates an eddy current in the battery cell, and the receiving coil detects signal changes caused by cracks, enabling non-destructive detection of internal defects without visual contact.
Solution Approach 2:
The patent introduces eddy current as an intermediary to detect cracks. The transmitting coil induces eddy current in the battery cell, and the receiving coil detects changes in this eddy current signal caused by cracks, using the eddy current as a mediator between the sensor and the defect.
2Measurement precision
If the cross-sectional area of the transmission unit and receiving unit are equal, then the sensor structure is simple and symmetric, but the difference between normal and defective signals is insufficient
Solution Approach 1:
The patent applies asymmetry by making the cross-sectional area of the transmission unit larger than that of the receiving unit. This asymmetric design amplifies the difference between normal and defective signals, improving crack detection sensitivity while maintaining a relatively simple sensor structure.
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 system effectively enhances the accuracy of crack detection in battery cells by amplifying the difference between normal and defective signals, enabling non-destructive evaluation of battery cells.
Implementation Method 1
a transmitting coil, which induces an eddy current to a target battery cell
Implementation Method 2
a receiving coil, which senses a signal change by the eddy current induced to the battery cell by the transmitting coil
Data Source
AI summary
The present invention relates to an eddy current sensor for detecting a crack in a battery cell. and a system for detecting a crack of a battery cell including the eddy current sensor. According to the present invention, it is possible to easily detect a crack generated in an electrode, an electrode tab or a welded portion.