In-depth evaluation of laser-welded similar and dissimilar material tab-to-busbar electrical interconnects for electric vehicle battery pack

Kumar, Nikhil; Masters, Iain; Das, Abhishek

doi:10.1016/j.jmapro.2021.08.025

Cited by 73 publications

(28 citation statements)

References 49 publications

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“…These were detected in EDS scanning spots, see the EDS phase compositions at selected scanning spots in Figure 14 . Observing the boundary region of the melt pool, it can be seen that spot 1 possibly consists of Cu solid solution, while spot 4 seems to have Cu solid solution [ 65 ]. However, spot 2 in the interface region of the weld seem to have Al 3 Cu 4 phase and spot 3 Al 2 Cu phase, which may have an adverse effect on the joint strength [ 66 ].…”

Section: Resultsmentioning

confidence: 99%

Seam Properties of Overlap Welding Strategies from Copper to Aluminum Using Green Laser Radiation for Battery Tab Connections in Electric Vehicles

et al. 2023

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Laser beam welding of metals has progressed dramatically over the last years mainly arising from joining applications in the field of electromobility. Allowing the flexible, automated manufacturing of mechanically, electrically, and thermally stressed components, the process is more frequently applied for joining highly reflective materials, for example for battery tab and busbar connections. The local, non-contact energy input favors this welding technology; however, joining of copper and aluminum sheets still poses a challenge due to the physical properties of the joining partners and intermetallic phases from dissimilar metal interaction, which reduce seam performance. The use of green laser radiation compared to infrared laser radiation offers the advantage of a significantly increased absorptivity for copper materials. A changed incoupling behavior is observed, and a lower deep penetration threshold has been already proven for 515 nm wavelength. When copper and aluminum are welded with the former as top sheet, this welding mode is essential to overcome limited aspect ratios from heat conduction welding. However, the opportunities of applying these beam sources in combination with spatial power modulation to influence the interconnection area of copper-aluminum joints have not yet been studied. The aim of this work is therefore to investigate the seam properties and process stability of different overlap welding strategies using green laser radiation for dissimilar metal welding. A microstructural analysis of the different fusion zones and mechanical strength of the joints are presented. In addition, the experimental parameter sets were analyzed regarding their application in battery module busbars by examining the electrical resistance and temperature distribution after welding. A parameter window was identified for all investigated welding strategies, with the stitched seam achieving the most stable results.

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Section: Resultsmentioning

confidence: 99%

Seam Properties of Overlap Welding Strategies from Copper to Aluminum Using Green Laser Radiation for Battery Tab Connections in Electric Vehicles

et al. 2023

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“…The thermo-electrical characterization of the unit cells was carried out during the cooling stage to the ambient temperature and began after reaching a temperature T 0 = 105 °C to match the limiting temperature established by the IEEE standard [19]. A four-point probe technique [20], using two measuring probes that were 100 mm distance apart and connected to a micro-ohmmeter KoCoS PROMET R600 supplying an electric current of 600 A during approximately 2 s, was used to measure the drop in voltage and determine the electrical resistance.…”

Section: Unit Cells and Thermo-electrical Characterizationmentioning

confidence: 99%

Double-sided injection lap riveting

Pragana

Sampaio

Chantreuil

et al. 2023

Int J Adv Manuf Technol

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This article presents a double-sided injection lap riveting process for fixing two overlapped sheets with tubular rivets at room temperature. The rivets are injected by compression into the dovetail ring holes that are previously machined in both sheets, and, in contrast to other joining by plastic deformation processes making use of auxiliary elements, the resulting joints are hidden inside the sheets without material protrusions above or below their surfaces. The new process is applied in the fabrication of aluminum busbar joints for energy distribution systems, and comparisons are made against conventional bolted joints that were fabricated for reference purposes. The work combines experimentation and finite element modelling, and results allow concluding that, in addition to invisibility and savings in assembly space, there are important gains in the thermo-electrical performance of the new joints that are of paramount importance for electric distribution applications.

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“…The electric resistance was determined by means of a four-point probe technique [20], and the two measuring probes were spaced 100 mm apart and connected to a micro-ohmmeter KoCoS PROMET R600 supplying an electric current of 600 A for approximately 2 s. The voltage drop 𝑉 measured by the probes allowed the determining of the electric resistance by means of the Ohm's law. The procedure was repeated each time the drop in temperature between two successive measurements was equal to ∆𝑇 = 𝑇 𝑛+1 − 𝑇 𝑛 = 5 °C.…”

Section: Thermo-electrical Characterization Of the Materials And Jointsmentioning

confidence: 99%

Injection Lap Riveting of Aluminum Busbars—A Thermo-Electro-Mechanical Investigation

Pragana

Sampaio

Bragança

et al. 2022

JMMP

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This paper presents a new mechanical joining process to assemble aluminum busbars in energy distribution systems. The process is based on the extension of injection lap riveting to the connection of busbars made from the same material as the rivets and requires redesigning the joints to ensure complete filling with good mechanical interlocking and appropriate contact pressures on the overlapping area. The experimental work was carried out in unit cells and involved the fabrication of the riveted joints and the evaluation of their electrical resistance at different service temperatures. Comparisons with the bolted joints that were fabricated and tested for reference purposes show that injection riveted joints provide lower values of electrical resistance and require much less space for assembly due to the absence of material protrusions above and below their surfaces. Numerical simulation with finite elements allows the relating of the reduction in electrical resistance with the changes in the electric current flow when the bolts are replaced by the new type of rivets. The experimental and numerical predictions revealed that the new type of rivets experience an increase in electrical resistance of up to 6 μΩ (30%) when the service temperature approaches 105 °C. Still, the resistance at this temperature (26.2 μΩ) is more than 3 times smaller than that of the bolted joints (80.5 μΩ).

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In-depth evaluation of laser-welded similar and dissimilar material tab-to-busbar electrical interconnects for electric vehicle battery pack

Cited by 73 publications

References 49 publications

Seam Properties of Overlap Welding Strategies from Copper to Aluminum Using Green Laser Radiation for Battery Tab Connections in Electric Vehicles

Seam Properties of Overlap Welding Strategies from Copper to Aluminum Using Green Laser Radiation for Battery Tab Connections in Electric Vehicles

Double-sided injection lap riveting

Injection Lap Riveting of Aluminum Busbars—A Thermo-Electro-Mechanical Investigation

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