Microstructural and Joint Analysis of Ultrasonic Welded Aluminum to Cupro-Nickel Sheets for Lithium-Ion Battery Packs

Energy crisis poses a major challenge in the modern industrial scenario. A critical aspect of the shop floor work includes the welding of dissimilar metal sheets which require the right amount of energy. In order to tackle these challenges, a conservative and energy efficient method are necessary. Recently, automotive industries have been widely adopted the ultrasonic metal welding process for assembling lithium-ion battery packs and its modules. The joining of these dissimilar metals using any other conventional welding process is extremely challenging due to varying physical, chemical, thermal properties, the formation of the heat affected zone and lesser bond strength. However, ultrasonic metal welding yields better quality welds under the influence of optimal parametric conditions. In this research, the weld quality of two dissimilar materials, namely, aluminum (AA1060) with cupronickel (C71500) sheets investigated at different welding time, vibration amplitudes and welding pressures with a fixed ultrasonic frequency of 20 kHz. Experimental results show the tensile shear strength of the weld is maximum at the highest vibration amplitude with a moderate amount of weld pressure and weld time. Additionally, the joint quality and its associated microstructure at the weld region are analyzed by scanning electron microscopy (SEM) to reveal the bond strength with the interlocking feature.

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Characterization of Ultrasonic Metal Welding by Correlating Online Sensor Signals With Weld Attributes

Volume 2: Processing ◽

10.1115/msec2014-4139 ◽

2014 ◽

Author(s):

S. Shawn Lee ◽

Chenhui Shao ◽

Tae Hyung Kim ◽

S. Jack Hu ◽

Elijah Kannatey-Asibu ◽

...

Keyword(s):

Welding Process ◽

Deep Understanding ◽

Lithium Ion ◽

Ultrasonic Welding ◽

Diagnostic Methods ◽

Quality Monitoring ◽

Process Conditions ◽

Ultrasonic Metal Welding ◽

Bond Density ◽

Metal Welding

Online process monitoring in ultrasonic welding of automotive lithium-ion batteries is essential for robust and reliable battery pack assembly. Effective quality monitoring algorithms have been developed to identify out of control parts by applying purely statistical classification methods. However, such methods do not provide the deep physical understanding of the manufacturing process that is necessary to provide diagnostic capability when the process is out of control. The purpose of this study is to determine the physical correlation between ultrasonic welding signal features and the ultrasonic welding process conditions and ultimately joint performance. A deep understanding in these relationships will enable a significant reduction in production launch time and cost, improve process design for ultrasonic welding, and reduce operational downtime through advanced diagnostic methods. In this study, the fundamental physics behind the ultrasonic welding process is investigated using two process signals, weld power and horn displacement. Several online features are identified by examining those signals and their variations under abnormal process conditions. The joint quality is predicted by correlating such online features to weld attributes such as bond density and post-weld thickness that directly impact the weld performance. This study provides a guideline for feature selection and advanced diagnostics to achieve a reliable online quality monitoring system in ultrasonic metal welding.

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Characterization of Ultrasonic Metal Welding by Correlating Online Sensor Signals With Weld Attributes

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4028059 ◽

2014 ◽

Vol 136 (5) ◽

Cited By ~ 20

Author(s):

S. Shawn Lee ◽

Chenhui Shao ◽

Tae Hyung Kim ◽

S. Jack Hu ◽

Elijah Kannatey-Asibu ◽

...

Keyword(s):

Welding Process ◽

Deep Understanding ◽

Lithium Ion ◽

Ultrasonic Welding ◽

Diagnostic Methods ◽

Quality Monitoring ◽

Process Conditions ◽

Ultrasonic Metal Welding ◽

Bond Density ◽

Metal Welding

Online process monitoring in ultrasonic welding of automotive lithium-ion batteries is essential for robust and reliable battery pack assembly. Effective quality monitoring algorithms have been developed to identify out of control parts by applying purely statistical classification methods. However, such methods do not provide the deep physical understanding of the manufacturing process that is necessary to provide diagnostic capability when the process is out of control. The purpose of this study is to determine the physical correlation between ultrasonic welding signal features and the ultrasonic welding process conditions and ultimately joint performance. A deep understanding in these relationships will enable a significant reduction in production launch time and cost, improve process design for ultrasonic welding, and reduce operational downtime through advanced diagnostic methods. In this study, the fundamental physics behind the ultrasonic welding process is investigated using two process signals, weld power and horn displacement. Several online features are identified by examining those signals and their variations under abnormal process conditions. The joint quality is predicted by correlating such online features to weld attributes such as bond density and postweld thickness that directly impact the weld performance. This study provides a guideline for feature selection and advanced diagnostics to achieve a reliable online quality monitoring system in ultrasonic metal welding.

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Ultrasonic Metal Welding of Multilayered Copper Foils to Nickel-Plated Copper Sheet in Lithium-Ion Battery Cell

Metals ◽

10.3390/met11081195 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1195

Author(s):

Seungmin Shin ◽

Sangwoo Nam ◽

Jiyoung Yu ◽

Jiyong Park ◽

Doncheol Kim

Keyword(s):

Lithium Ion Battery ◽

Mechanical Performance ◽

Lithium Ion ◽

Pressure Amplitude ◽

Characteristic Analysis ◽

Battery Cell ◽

Ultrasonic Metal Welding ◽

Metal Welding ◽

Welding Pressure ◽

Battery Cells

The battery performance of electric vehicles depends on the density and capacity of the battery; thus, the battery cells must be assembled in as many layers as possible. Electric vehicle batteries are typically composed of several cells which form modules connected by busbars, with dozens of modules manufactured as battery packs. The ultrasonic metal welding (UMW) technology is applied to such multilayered foil welding. This study analyzed UMW to ensure the weldability of multilayered Cu foils and a Ni-plated Cu strip in lithium-ion battery cells through various approaches. In UMW, the effect of the alignment on weld production and quality were examined through the energy and mechanical performance of the weld by conducting comparative experiments on the alignment of the horn and anvil. Additionally, the effects of UMW process parameters, such as the welding pressure, amplitude, and welding time, were statistically analyzed. The weldability evaluation and characteristic analysis were performed based on these variables. Furthermore, the cross-sectional shapes and microstructure behavior of the Ni layers were analyzed based on the weld quality.

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