Pouch Cell Eddy Current Inspection for Crack and Weld Defects
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Solution Overview
Problem
Existing quality inspection methods for pouch-type secondary battery cells are limited in their ability to precisely detect microscopic cracks, short circuits, and weld defects across the entire surface of the cells, and are sensitive to measurement distance and positional errors, leading to inaccurate inspections.
Innovation Solution
A quality inspection device and method that induces a current to flow throughout the pouch-type secondary battery cell, using AC signal generation, magnetic field generation, and multiple induced current detection sensors to scan and compare detected current signals with preset criteria, accurately identifying defects in electrode plates, bent portions, and welds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional inspection methods are used, then the inspection process is simple, but the measurement precision and defect detection accuracy are insufficient
Solution Approach 1:
The inspection device is divided into multiple independent sensor units, each responsible for detecting specific defect types (cracks, short circuits, weld defects) at different locations. This segmentation allows each sensor to be optimized for its specific detection task, improving overall measurement precision while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The patent introduces a control unit as an intermediary that coordinates multiple sensors and processes their signals. This intermediary component integrates information from various sensors, enabling precise defect detection without requiring each sensor to independently handle all detection tasks, thus improving accuracy while managing system complexity.
2Measurement precision
If multiple sensors are used to inspect the entire surface, then the defect detection coverage is improved, but the device complexity and measurement sensitivity to positional errors increase
Solution Approach 1:
The sensor units are designed with multi-functionality, capable of detecting multiple defect types (cracks, short circuits, weld defects) across different battery cell regions. This universal design allows comprehensive surface coverage without proportionally increasing device complexity, as each sensor performs multiple detection functions simultaneously.
Solution Approach 2:
The control unit implements feedback mechanisms that monitor the signals from multiple sensors and adjust the inspection process accordingly. This feedback system compensates for positional errors and coordinates sensor operations, enabling comprehensive defect detection while reducing the impact of measurement uncertainties on overall system complexity.
3Measurement precision
If the inspection device is sensitive to measurement distance, then the detection precision may be improved under ideal conditions, but the reliability decreases due to positional errors
Solution Approach 1:
The inspection system employs dynamic adjustment capabilities where the control unit modifies detection parameters based on real-time measurements from multiple sensors. This dynamic adaptation allows the system to maintain detection precision across varying measurement distances and positions, thereby improving reliability without sacrificing precision under ideal conditions.
Solution Approach 2:
The patent utilizes parameter changes in the detection signals and processing algorithms to compensate for variations in measurement distance and position. By adjusting detection parameters and signal processing methods based on actual measurement conditions, the system maintains high detection precision while ensuring reliable operation across different positional scenarios.
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 defects such as cracks, short circuits, and weld issues, determining their location and severity, even in non-uniform cells with positional errors, ensuring safety by identifying potential hazards.
Implementation Method 1
an AC signal generating unit that generates an AC signal; a magnetic field generating means that generates a magnetic field according to the AC signal and induces a current to flow in the pouch-type secondary battery cell
Implementation Method 2
at least one induced current detection sensors for detecting a signal of the induced current flowing in the pouch-type secondary battery cell
Data Source
AI summary
Provided is a quality inspection device and method for a pouch-type secondary battery cell, which inspects the quality of a plate, a bent portion, or a weld portion of a pouch-type secondary battery cell. An AC signal generating unit generates an AC signal. A magnetic field generating unit generates a magnetic field in accordance with the generated AC signal and induces a current to flow in a pouch-type secondary battery cell. At least one induced current detection sensors each detect the signal of the induced current flowing in the pouch-type secondary battery cell. A control/judgment unit compares the detected induced current signal with a value of a preset judgment range and judges the quality of the pouch-type secondary battery cell.