Transient Temperature and Heat Flux Measurement in Ultrasonic Joining of Battery Tabs Using Thin-Film Microsensors

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Hang Li ◽  
Hongseok Choi ◽  
Chao Ma ◽  
Jingzhou Zhao ◽  
Hongrui Jiang ◽  
...  
Keyword(s):  
Thin Film ◽  
Heat Flux ◽  
Heat Generation ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Transient Temperature ◽  
Monitoring And Control ◽  
Change Rate ◽  
Flux Change ◽  
And Control

Process physics understanding, real time monitoring, and control of various manufacturing processes, such as battery manufacturing, are crucial for product quality assurance. While ultrasonic welding has been used for joining batteries in electric vehicles (EVs), the welding physics, and process attributes, such as the heat generation and heat flow during the joining process, is still not well understood leading to time-consuming trial-and-error based process optimization. This study is to investigate thermal phenomena (i.e., transient temperature and heat flux) by using micro thin-film thermocouples (TFTC) and thin-film thermopile (TFTP) arrays (referred to as microsensors in this paper) at the very vicinity of the ultrasonic welding spot during joining of three-layered battery tabs and Cu buss bars (i.e., battery interconnect) as in General Motors's (GM) Chevy Volt. Microsensors were first fabricated on the buss bars. A series of experiments were then conducted to investigate the dynamic heat generation during the welding process. Experimental results showed that TFTCs enabled the sensing of transient temperatures with much higher spatial and temporal resolutions than conventional thermocouples. It was further found that the TFTPs were more sensitive to the transient heat generation process during welding than TFTCs. More significantly, the heat flux change rate was found to be able to provide better insight for the process. It provided evidence indicating that the ultrasonic welding process involves three distinct stages, i.e., friction heating, plastic work, and diffusion bonding stages. The heat flux change rate thus has significant potential to identify the in-situ welding quality, in the context of welding process monitoring, and control of ultrasonic welding process. The weld samples were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to study the material interactions at the bonding interface as a function of weld time and have successfully validated the proposed three-stage welding theory.

scholarly journals Continuous ultrasonic welding of thermoplastic composites: Enhancing the weld uniformity by changing the energy director

2019 ◽  
Vol 54 (15) ◽  
pp. 2023-2035 ◽  
Author(s):  
Bram Jongbloed ◽  
Julie Teuwen ◽  
Genevieve Palardy ◽  
Irene Fernandez Villegas ◽  
Rinze Benedictus
Keyword(s):  
Thin Film ◽  
Heat Generation ◽  
High Speed ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Thermoplastic Composites ◽  
Weld Strength ◽  
Good Contact ◽  
Energy Director ◽  
Welded Seam

Continuous ultrasonic welding is a high-speed joining method for thermoplastic composites. Currently, a thin film energy director is used to focus the heat generation at the interface. However, areas of intact energy director remain in the welded seam, which significantly lowers the weld strength, and result in a non-uniformly welded seam. To improve the weld uniformity of continuous ultrasonically welded joints, we changed to a more compliant energy director. A woven polymer mesh energy director was found to give a significant improvement in weld quality. The mesh was flattened in between the composite adherends during the welding process. This flattening promoted a good contact between the energy director and the adherends, fully wetting the adherend surfaces, resulting in a more uniformly welded seam without areas of intact energy director.

Micro Thin Film Sensor Embedded in Metal Structures for In-Situ Process Monitoring During Ultrasonic Welding

2005 ◽  
Author(s):  
Xudong Cheng ◽  
Xiaochun Li
Keyword(s):  
Thin Film ◽  
Heat Generation ◽  
Welding Process ◽  
Ultrasonic Welding ◽  
Weld Strength ◽  
Welding Parameter ◽  
Welding Parameters ◽  
Thin Film Sensors ◽  
Welding Interface

The objective of this research is to develop an effective method, i.e., ultrasonic metal welding (USMW), to embed micro thin film sensors for metal tooling, and use micro thin film thermocouple study the heat generation during USMW. A complete understanding of the fundamental mechanisms of USMW does not yet exist, and the function of heat generation on weld formation is especially in argument due to the lack of the method to measure the temperature at the welding interface. Continuing on the previous preliminary study [1] which proved that thin film sensors can survive ultrasonic welding process, significant advances were made to improve sensor reliability as well as sensor fabrication effectiveness. These include the development of a new approach for batch production of the sensor units, improvement of the adhesion between metal encapsulating layers for the sensor, as well as the adhesion between the sensing layer and the dielectric layer. Welding experiments are conducted using a series of welding parameter settings with the in-situ data acquisition of temperature 50 μm away from the welding interface. Attempts are then made to correlate the heat generation to welding parameters. With the mechanical testing of the weld strength, the possibility of using heat generation as a weld strength indicator is explored.

Infrared Sensing for On-Line Weld Geometry Monitoring and Control

1995 ◽  
Vol 117 (3) ◽  
pp. 323-330 ◽  
Author(s):  
P. Banerjee ◽  
S. Govardhan ◽  
H. C. Wikle ◽  
J. Y. Liu ◽  
B. A. Chin
Keyword(s):  
Plate Thickness ◽  
Welding Process ◽  
Temperature Gradients ◽  
Monitoring And Control ◽  
Depth Of Penetration ◽  
Bead Width ◽  
Weld Geometry ◽  
On Line ◽  
And Control ◽  
Welding Processes

This paper describes a method for on-line weld geometry monitoring and control using a single front-side infrared sensor. Variations in plate thickness, shielding gas composition and minor element content are known to cause weld geometry changes. These changes in the weld geometry can be distinctly detected from an analysis of temperature gradients computed from infrared data. Deviations in temperature gradients were used to control the bead width and depth of penetration during the welding process. The analytical techniques described in this paper have been used to control gas tungsten arc and gas metal arc welding processes.

Micro Thin Film Sensor Embedding in Metals by Ultrasonic Welding for Production of Miniature Smart Tooling

2004 ◽  
Author(s):  
Xudong Cheng ◽  
Patrick Schwieso ◽  
Hongseok Choi ◽  
Arindom Datta ◽  
Xiaochun Li
Keyword(s):  
Thin Film ◽  
Thin Sheet ◽  
Welding Process ◽  
Weld Interface ◽  
Ultrasonic Welding ◽  
Film Sensor ◽  
Thin Film Sensor ◽  
Safety And Reliability ◽  
Thin Film Thermocouples ◽  
Nickel Strip

This work is to study micro thin film sensor embedding in metals for the production of miniature smart tooling. This technique promises to significantly improve the safety and reliability for manufacturing processes and reduce operation costs. One key concern of the current research is to investigate if sensor functionality can be maintained during and after embedding in metals by use of ultrasonic welding (USW), which could be hostile to micro thin film thermocouples (TFTCs) embedded near the welding interface. The welding workpieces, consisting of a nickel strip with embedded micro sensors and a copper thin sheet, were welded by USW process. Experimental results showed that TFTCs survived the ultrasonic welding process. The embedded TCFCs were also capable of measuring temperature in-situ near the weld interface during the embedding process.

Evaluation of response characteristics of thin film gauge for conductive heat transfer mode

2020 ◽  
pp. 014233122096066
Author(s):  
Tanweer Alam ◽  
Rakesh Kumar
Keyword(s):  
Thin Film ◽  
Heat Transfer ◽  
Heat Flux ◽  
Short Duration ◽  
Temperature Data ◽  
Heat Transfer Analysis ◽  
Transient Temperature ◽  
Conductive Heat ◽  
Sensing Element ◽  
Element Analysis

Heat transfer analysis is the one of the most important designing aspects for many engineering systems. The design prospect in the preview of heat transfer focuses on the prediction of heat flux with the help of measured transient temperature data. Thin film gauges are one of the most predominant method for the heat flux prediction especially for short duration transient temperature measurement. Thin film gauges are usually exposed to the heated environment for the measurement purpose. However, there are some prominent research areas like ablation phenomenon met to spacecraft thermal shields during re-entry to the atmosphere, for which direct exposure of the thin film gauge to the heated environment causes the functional and working difficulties associated with the gauge. In the present study, it is aimed to investigate the suitability of thin film gauge for the conduction-based short duration measurement. An experimental set up is fabricated, which is used to supply the heat load to the hand-made thin film gauge using platinum as sensing element and quartz as a substrate. The transient temperature data is recorded during experiment is further compared with the simulated temperature histories obtained through finite element analysis. The heat flux estimation for both the analysis is made using measured transient temperature data by convolute integral of one- dimensional heat conduction equation. The estimated heat flux value for the experimental and numerical result is found to be in excellent agreement.

437 Visual Monitoring and Control of Butt Welding Process in MAG Welding

2010 ◽  
Vol 2010.18 (0) ◽  
pp. _437-1_-_437-3_
Author(s):  
Hideki ICHIKAWA ◽  
M.R. ZAHIDIN ◽  
Akira NINOMIYA ◽  
Yasuo SUGA
Keyword(s):  
Welding Process ◽  
Mag Welding ◽  
Monitoring And Control ◽  
Visual Monitoring ◽  
Butt Welding ◽  
And Control
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