Button Battery Tab Welding With In-Line Resistance Defect Detection
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Solution Overview
Problem
Existing welding devices for button-type secondary batteries lack the ability to immediately detect welding defects, which are indicated by variations in internal resistance, making it difficult to ensure proper contact and electrical integrity between the electrode tab and the can.
Innovation Solution
A welding device equipped with a base, a jig, a laser irradiation device, and four probes that measure resistance by applying current and voltage to determine if welding defects occur, using a controller to compare calculated resistance with input data to assess welding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser welding is performed to join electrode tab to can, then welding strength is improved, but inability to immediately detect welding defects causes reliability deterioration
Solution Approach 1:
The resistance measurement function is prepared in advance and automatically executed immediately after laser welding completes. The control unit triggers the measurement without manual intervention, ensuring welding defects are detected at the earliest possible moment before the battery proceeds to next assembly steps.
Solution Approach 2:
The system establishes a closed-loop feedback mechanism where resistance measurement results are automatically fed back to the control unit. Based on this feedback, the system can identify welding defects and trigger appropriate responses, enabling continuous quality monitoring and process improvement.
2Measurement precision
If resistance measurement is added to detect welding defects, then welding quality detection is improved, but device complexity increases
Solution Approach 1:
The probe unit serves multiple functions: it applies contact force to ensure electrical contact, provides electrical connection for resistance measurement, and can be integrated with the existing laser welding apparatus. This multi-functionality reduces the need for separate dedicated measurement equipment.
Solution Approach 2:
The resistance measurement system is merged with the existing laser welding apparatus by integrating the control unit and probe unit into the same mechanical structure. The probe unit is positioned to work in conjunction with the laser welding head, combining welding and measurement functions in a single integrated system.
3Adaptability or versatility
If probe positioning is made adjustable to accommodate various battery sizes, then adaptability is improved, but device complexity increases
Solution Approach 1:
The probe positioning system employs movable and adjustable components that can be dynamically reconfigured for different battery sizes. The probe unit can be positioned at various locations on the can and electrode tab assembly, allowing the system to adapt to different button battery dimensions while maintaining measurement accuracy.
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 immediate detection of welding defects by measuring resistance, ensuring proper contact and electrical integrity between the electrode tab and the can, and accommodating batteries of various sizes with adjustable probe positioning to prevent thermal damage.
Implementation Method 1
laser for welding the electrode tab to the can passes through the opening hole
Implementation Method 2
laser is irradiated to weld the negative electrode tab on a bottom surface inside the lower can
Implementation Method 3
two probes are connected to a power source so that current flows to welding portions of the can and the electrode tab, and remaining two probes are connected to a voltmeter to measure voltages at the welding portions
Implementation Method 4
A resistance value between the electrode tab and the can varies in magnitude according to a length of a bead generated at the welded portion during the welding
Data Source
AI summary
A welding device welds an electrode tab protruding from an electrode assembly of a button-type battery to a can of the button-type battery. The welding device includes a base to support a bottom surface of the can when an inner surface of the can faces an upper side, and the electrode tab is in contact with the inner surface of the can; a jig on the base to fix the electrode tab on the base and having an opening hole through which a laser light for welding the electrode tab to the can passes; a laser irradiation device to irradiate the laser light to the opening hole when the jig fixes the electrode tab to the can; and four probes on the base or the jig. Two probes of the probes are connected to a power source, and the remaining two probes are connected to a voltmeter.