Eddy Current Coil Layout for Sealed Battery Crack Detection
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Solution Overview
Problem
Existing methods fail to non-destructively detect cracks in sealed battery cells, particularly in stack-folding type batteries, which are difficult to inspect visually due to internal cracks post-sealing.
Innovation Solution
An eddy current sensor with a transmission unit and a receiving unit, where the cross-sectional area of the transmission unit is greater than the receiving unit, is used to induce and sense eddy currents, enhancing signal differentiation for crack detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visual inspection is used to detect cracks in battery cells, then the inspection method is simple and non-destructive, but internal cracks in sealed battery cells cannot be detected
Solution Approach 1:
The patent replaces visual inspection with eddy current sensing technology. The eddy current sensor uses electromagnetic induction to generate eddy currents in the battery cell, and detects changes in these currents caused by cracks, thereby achieving non-destructive detection of internal defects without requiring visual access.
Solution Approach 2:
The patent introduces an eddy current field as an intermediary between the sensor and the crack defect. The transmitting coil generates eddy currents that penetrate the battery cell, and the receiving coil detects disturbances in these eddy currents caused by cracks, enabling indirect detection of internal defects.
2Measurement precision
If the cross-sectional area of the transmission unit and receiving unit are equal, then the sensor structure is simple, but the signal differentiation for crack detection is insufficient
Solution Approach 1:
The patent applies asymmetry by setting the cross-sectional area of the transmission unit larger than that of the receiving unit. This asymmetric configuration creates a gradient in the eddy current distribution, enhancing the sensitivity of the receiving coil to detect cracks while maintaining a manageable sensor structure.
Solution Approach 2:
The patent assigns different functions and sizes to different parts of the sensor: the transmission unit with larger cross-sectional area is optimized for generating strong eddy currents, while the receiving unit with smaller cross-sectional area is optimized for detecting subtle changes. This local differentiation improves overall detection precision.
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 sensor accurately detects cracks in electrodes, electrode tabs, and welds within battery cells by amplifying signal changes, improving detection accuracy.
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
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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 weld.