Multi-mode Ultrasonic Welding Control for Battery Tab Integrity
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Solution Overview
Problem
Single mode control strategies in ultrasonic welding, such as monitoring and controlling only welding energy, time, or compression displacement, often result in random low probability weld integrity issues in bonding battery tabs to interconnect bus bars in electric vehicle battery packs.
Innovation Solution
A multi-mode control system that combines weld energy, weld time, and compression displacement thresholds to determine when to terminate the welding process, allowing for open-loop or closed-loop feedback to adjust power and pressure accordingly, ensuring consistent weld integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single mode control (monitoring only welding energy, time, or compression displacement) is used, then the control system is simple, but weld integrity becomes unreliable due to random low probability issues
Solution Approach 1:
The patent combines multiple control modes (welding energy, welding time, and compression displacement) into a unified control system. The controller integrates these different parameters and terminates the welding process only when thresholds for multiple modes are satisfied, thereby improving weld integrity while managing system complexity through systematic integration.
2Reliability
If multi-mode control monitoring all welding parameters is implemented, then weld integrity is improved, but the control system complexity increases
Solution Approach 1:
The control system is segmented into distinct control modes (energy mode, time mode, displacement mode), each with its own threshold criteria. The controller evaluates each mode independently and terminates the welding process when thresholds for multiple modes are satisfied, allowing systematic management of complexity while ensuring comprehensive monitoring for improved weld integrity.
3Ease of manufacture
If welding process is terminated based on single parameter threshold, then the control process is simple, but random low probability weld integrity issues occur
Solution Approach 1:
The controller implements feedback mechanisms that continuously monitor multiple welding parameters (energy, time, compression displacement) and compare them against predetermined thresholds. The welding process is terminated only when thresholds for multiple modes are satisfied, providing comprehensive feedback control that eliminates random weld integrity issues while maintaining systematic control simplicity.
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 multi-mode control system enhances weld integrity by selectively terminating the process based on multiple parameters, reducing random integrity issues and allowing for precise control of weld energy and displacement rates, thereby improving the reliability of the bonding process.
Implementation Method 1
A horn or sonotrode of a vibrational welding machine is placed against the parts being welding and ultrasonic sound energy from a transducer causes the parts to vibrate
Implementation Method 2
which creates friction that generates a large amount of heat to bond the parts together
Data Source
AI summary
A system and method for providing multi-mode control of an ultrasonic welding system. In one embodiment, the control modes include the energy of the weld, the time of the welding process and the compression displacement of the parts being welded during the welding process. The method includes providing thresholds for each of the modes, and terminating the welding process after the threshold for each mode has been reached, the threshold for more than one mode has been reached or the threshold for one of the modes has been reached. The welding control can be either open-loop or closed-loop, where the open-loop process provides the mode thresholds and once one or more of those thresholds is reached the welding process is terminated. The closed-loop control provides feedback of the weld energy and/or the compression displacement so that the weld power and/or weld pressure can be increased or decreased accordingly.