Process robustness of single lap ultrasonic welding of thin, dissimilar materials

Kim, T.H.; Yum, Juil; Hu, S. Jack; Spicer, J. Patrick; Abell, Jeffrey A.

doi:10.1016/j.cirp.2011.03.016

Cited by 104 publications

(49 citation statements)

References 10 publications

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“…The work by Kim et al [23] studied the ultrasonic welding for battery tabs with like and dissimilar metals. In a follow-up study by Lee et al [44], the quality of ultrasonically welded battery tab was characterized.…”

Section: Introductionmentioning

confidence: 99%

“…For ultrasonic welding of copper, Elangovan et al [22] performed experimental study based on a design of experiment method, and identified several critical process parameters. The ultrasonic welding of nickel coated Cu/Cu tab was studied by Kim et al [23]. In the study, a factorial experimental design and peeling test were performed, and three categories of weld quality (cold, good and over-welds) was mapped in the welding time-welding pressure domain.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure, welding mechanism, and failure of Al/Cu ultrasonic welds

Cai

2015

Journal of Manufacturing Processes

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Please cite this article in press as: Wu X, et al. Microstructure, welding mechanism, and failure of Al/Cu ultrasonic welds. J Manuf Process (2015), http://dx. a b s t r a c tUltrasonic metal welding has been used widely to join battery cell terminals, or tabs (either Al or Cu), with bus bars (Cu) to form assembled battery packs in battery electric vehicles. However, the mechanism of ultrasonic welding for Al/Cu is still not well understood. In this work, the microstructures of the ultrasonic welds between three layers of lithium-ion battery tabs (either Al or Cu) and bus bars were studied. From the microstructure analysis, the weld formation mechanism and failure modes were investigated. It was found that the metal inter-mix is the main weld formation mechanism at the Al-Al interfaces, while friction-induced physical bonding is the main mechanism at Cu-Cu or Al-Cu interfaces. Metallographs also indicated that the weld failure is a combination of the interfacial debonding between the innermost tab (either Cu or Al) and the Cu bus bar and the through-thickness tearing of the tabs. The presented work provides better understanding of weld formation and failure, and hence provide insight into ultrasonic welding process toward weld quality improvement. This understanding and insight can be used to develop science-based design guidelines toward selecting the most appropriate materials and welding process parameters.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructure, welding mechanism, and failure of Al/Cu ultrasonic welds

Cai

2015

Journal of Manufacturing Processes

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“…Efforts have been taken to investigate several joining technologies, such as resistance welding, laser welding, ultrasonic welding, and mechanical fastening [1,2]. Among all these techniques, ultrasonic welding, a solid state joining process, is widely regarded as one of the best for battery joining due to its capability of joining dissimilar, multiple, and thin layers at low temperatures [3][4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

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

Li¹,

Choi²,

Ma³

et al. 2013

Journal of Manufacturing Science and Engineering

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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 (TETC) and thin-film thermopile (TETP) 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 TETCs enabled the sensing of transient temperatures with much higher spatial and temporal resolutions than conventional thermocouples. It was further found that the TETPs were more sensitive to the transient heat generation process during welding than TETCs. 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 insitu 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.

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“…Kim et al [12] did the ultrasonic welding experiments by taking materials such as copper and nickel plated copper. They proposed a quality lobe to categorize the different types of failure, such as nugget, interfacial and button failure modes by conducting T-peel tests.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Horn Design and Effects of Process Parameters on Properties of Dissimilar Ultrasonic Welding Aluminum to Brass

Satpathy

Sahoo

Datta

2015

Materials and Manufacturing Processes

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Ultrasonic welding technology is the new and emerging concept, which can be applied to many industrial applications. The vital part of this technology is the horn, which acts as a tool, upon which the pressure and high frequency vibration is applied to create a solidstate weld. In this study, a special type of horn is designed and its length is determined analytically. Dimensions obtained by finite element method (FEM) are employed for the horn used in the present experiments to weld brass with aluminium sheet of thickness 0.1 mm. The dynamic analysis is also performed to find out the stress and amplitude distribution in the horn under loading conditions. Welding has been carried out using various parameter combinations in order to improvise the weld strength. Maximum weld strength of 4.05 MPa is obtained under the optimum welding conditions of 0.21 sec weld time, 0.26 MPa weld pressure and 60µm vibration amplitude. The microhardness test also has been done on the optimized results to show the plastic flow at the weld zone. It confirms that the hardness of both materials up to 20µm distance around the weld zone is increased with respect to the parent materials.

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Process robustness of single lap ultrasonic welding of thin, dissimilar materials

Cited by 104 publications

References 10 publications

Microstructure, welding mechanism, and failure of Al/Cu ultrasonic welds

Microstructure, welding mechanism, and failure of Al/Cu ultrasonic welds

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

Acoustic Horn Design and Effects of Process Parameters on Properties of Dissimilar Ultrasonic Welding Aluminum to Brass

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