Battery Electrode Tab Disconnection Detection Using EIS Resonance
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Solution Overview
Problem
Existing methods for inspecting disconnection of electrode tabs in battery cells are inefficient for mass production due to the need for physical pressing and lengthy CT image capturing, making them unsuitable for quick and scalable inspection.
Innovation Solution
An apparatus and method using electrochemical impedance spectroscopy (EIS) to measure impedance values and angles over frequency, calculating real part resistance values, and determining disconnection by comparing these values with established ranges for good battery cells, allowing for non-destructive and rapid inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate pressing device is used to measure impedance change, then disconnection detection is possible, but the inspection process becomes complex and unsuitable for mass production
Solution Approach 1:
The patent extracts the pressing function from a separate mechanical pressing device and integrates it into the inspection probe itself. The probe directly applies pressing force to the battery cell terminal while measuring impedance, eliminating the need for separate pressing equipment and reducing overall system complexity while maintaining detection accuracy
Solution Approach 2:
The inspection probe is designed to perform multiple functions: it both applies pressing force to the battery terminal and measures impedance simultaneously. This multi-functional design consolidates what would otherwise require separate devices, making the inspection process suitable for mass production while maintaining reliable disconnection detection
2Reliability
If CT image capturing is used to physically inspect welding location, then disconnection can be detected, but the inspection time is too long (about 1 minute 30 seconds per cell)
Solution Approach 1:
The patent replaces the mechanical/physical CT scanning system with an electrical impedance measurement system. Instead of using X-ray CT to physically inspect welding locations, the probe measures electrical impedance changes that occur when the battery terminal is pressed, providing equivalent disconnection detection information much faster
Solution Approach 2:
The patent changes the measurement parameter from physical structure imaging (CT scan) to electrical property measurement (impedance). By measuring impedance changes that occur during terminal pressing, the system detects disconnections through electrical parameter variations rather than physical imaging, dramatically reducing inspection time while maintaining detection accuracy
3Productivity
If conventional impedance measurement without pressing is used, then the inspection is simple and fast, but it cannot detect disconnection effectively
Solution Approach 1:
The patent applies preliminary action by pressing the battery terminal before and during impedance measurement. This pre-applied mechanical stress creates the necessary conditions for detecting disconnections, as the pressing force reveals impedance changes that would not be apparent under normal conditions. The pressing action is performed immediately before measurement, ensuring detection sensitivity while maintaining inspection speed
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 quick and efficient mass-production level inspection of electrode tab disconnections without physical pressure, preventing defective battery cells from being shipped and facilitating inspections in both manufacturing and recycling stages.
Implementation Method 1
a measurement part for measuring impedance values and impedance angles of a inspection target battery cell over frequency
Implementation Method 2
a calculation part for calculating real part resistance values of impedance of the inspection target battery cell over frequency from the impedance values and the impedance angles
Data Source
AI summary
An apparatus for inspecting disconnection of an electrode tab of a battery cell includes a measurement part which measures impedance values and impedance angles of an inspection target battery cell over frequency; a calculation part which calculates real part resistance values of impedance of the inspection target battery cell over frequency from the impedance values and the impedance angles; and a determination part which determines whether an electrode tab of the battery cell is disconnected by comparing real part resistance values in a real part resistance value range in a resonance frequency range of good battery cells having the same type as the inspection target battery cell with the real part resistance values of the impedance of the inspection target battery cell in the same frequency range as the resonance frequency range.