Laser edge welding of thick Cu busbars for termination: role of edge shape

Seungwon Jeong; Joonghan Shin

doi:10.1007/s40436-026-00615-x

Advances in Manufacturing ›› :1 -16. DOI: 10.1007/s40436-026-00615-x

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Laser edge welding of thick Cu busbars for termination: role of edge shape

Seungwon Jeong ¹
, Joonghan Shin ¹^,²^,³^,^a

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¹Department of Future Convergence Engineering, Kongju National University, 31080, Cheonan, Republic of Korea

²Department of Mechanical and Automotive Engineering, Kongju National University, 31080, Cheonan, Republic of Korea

³Global Institute of Manufacturing Technology, Kongju National University, 31080, Cheonan, Republic of Korea

^a jhshin@kongju.ac.kr

Seungwon Jeong

Seungwon Jeong received M.S. degree in Future Convergence Engineering from Kongju National University in 2025. Now he is a Ph.D. student at Kongju National University. His interests include metallurgical characterization and monitoring in laser-based manufacturing processes.

Joonghan Shin

Joonghan Shin received B.S. degree in Mechanical Engineering from Inha Univiersity, Korea in 2001, M.S. degree in Mechanical And Aerospace Engineering from Seoul National University, Korea in 2003 and Ph.D. degree in Mechanical Engineering from University of Michigan, USA in 2010. From 2010 to 2017, he was a research engineer at semiconductor R&D center, Samsung Electronics Co., Ltd., Korea. He joined Kongju National University, Korea in 2017. He is currently an associate professor in Department of Mechanical and Automotive Engineering and Department of Future Convergence Engineering. His interests include laser material processing, intelligent manufacturing system, precision engineering, and material characterization.

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Abstract

The busbar, one of the electrical connectors in electric-vehicle battery packs, undergoes a process to form a terminal at its end (i.e., a termination). In this study, laser edge welding was performed on two types of busbars (round and square) for busbar termination, and the weld formation mechanisms and joint properties were analyzed. In the round busbar, the curved shape of the edge forms a groove, resulting in different welding characteristics compared with the square-type busbar, which has a flat edge. In round-type welding, the groove structure increased thermal interaction at the laser-material interface, producing a total weld depth 0.24 mm greater than that of the square type; it also caused the grain growth direction to branch into two distinct paths. Additionally, cracks of approximately 100 $\upmu $m size were sporadically observed in round-type welds; this effect was attributed to the constraint on shrinkage deformation imposed by the groove structure. The mean hardness of the square-type weld remained uniform at 63.74 HV, whereas the hardness in the round-type weld decreased to 28.8 HV in cracked regions. For both edge types, the electrical resistance of the joints decreased with increasing weld depth. However, the round-type joint exhibited the electrical resistance 2.4 $\upmu \Omega $ higher than that of the square type, as a result of differences in dislocation density of the base metal. This study also provides in-depth insights into the heat transfer mechanism of laser edge welding based on the geometric shape of the busbar, which is a decisive factor influencing welding characteristics.

Keywords

Cu busbar / Busbar edge shape / Laser edge welding / Microstructure / Mechanical property / Electrical property

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Seungwon Jeong, Joonghan Shin. Laser edge welding of thick Cu busbars for termination: role of edge shape. Advances in Manufacturing 1-16 DOI:10.1007/s40436-026-00615-x

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References

Publishing order | Descend order by publishing year | Descend order by cited within

[1]	Miao Y, Liu L, Zhang Y, et al.. An overview of global power lithium-ion batteries and associated critical metal recycling. J Hazard Mater, 2021, 425: 127900.

[2]	Adepetu A, Keshav S. The relative importance of price and driving range on electric vehicle adoption: Los Angeles case study. Transportation, 2017, 44: 353-373.

[3]	Koehler U. Korthauer R. Lithium-ion battery system design. Lithium-ion batteries: basics and applications, 2018, 1, Berlin, Springer: 89-100.

[4]	Harper G, Sommerville R, Kendrick E, et al.. Recycling lithium-ion batteries from electric vehicles. Nature, 2019, 575: 75-86.

[5]	Gomes VB, Kasaei MM, Carbas RJC, et al.. A new joining by forming process for busbar-prismatic cell interconnections in electric vehicle batteries. Int J Adv Manuf Technol, 2025, 137: 2405-2432.

[6]	Das A, Li D, Williams D, et al.. Joining technologies for automotive battery systems manufacturing. World Electr Veh J, 2018, 9: 22.

[7]	Wang PE, Ghassemi-Armaki H, Pour M, et al.. Applicable and generalizable machine learning for intelligent welding in automotive manufacturing. Weld World, 2025, 69: 1349-1384.

[8]	Kumar N, Pamarthi VV, Das A. Investigating laser and ultrasonic welding of pouch cell multi-foil current collectors for electric vehicle battery fabrication. Int J Adv Manuf Technol, 2024, 134: 2497-2511.

[9]	Brand MJ, Schmidt PA, Zaeh MF, et al.. Welding techniques for battery cells and resulting electrical contact resistances. J Energy Storage, 2015, 1: 7-14.

[10]	Francioso M, Angeloni C, Fortunato A, et al.. Experimental investigation on the effect of nickel-plating thickness on continuous-wave laser welding of copper and steel tab joints for battery manufacturing. Lasers Manuf Mater Process, 2024, 11: 353-370.

[11]	Cao L, Liu Y, Chen H, et al.. Investigation of intermetallics formation and joint performance of laser welded Ni to Al. Appl Sci, 2023, 13: 1356.

[12]	Solchenbach T, Plapper P, Cai W. Electrical performance of laser braze-welded aluminum-copper interconnects. J Manuf Process, 2014, 16: 183-189.

[13]	Das A, Masters I, Haney P. Modelling the impact of laser micro-joint shape and size on resistance and temperature for electric vehicle battery joining application. J Energy Storage, 2022, 52: 104868.

[14]	Lassila AA, Lönn D, Andersson T, et al.. Effects of different laser welding parameters on the joint quality for dissimilar material joints for battery applications. Opt Laser Technol, 2024, 177: 111155.

[15]	Fortunato A, Ascari A. Laser welding of thin copper and aluminum sheets: feasibility and challenges in continuous-wave welding of dissimilar metals. Lasers Manuf Mater Process, 2019, 6: 136-157.

[16]	Sun T, Jabar S, Kumar N, et al.. The impact of ring-shaped laser beam on dissimilar welding of Al-Cu thin sheets for battery tab-to-busbar connection: microstructural, mechanical and electrical characteristics. Opt Laser Technol, 2024, 179: 111312.

[17]	Jabar S, Sun T, Franciosa P, et al.. Effect of a ring-shaped laser beam on the weldability of aluminum-to-hilumin for battery tab connectors. J Laser Appl, 2023, 35: 042038.

[18]	Mypati O, Anwaar T, Mitra D, et al.. Characterization and modelling of Al and Cu busbar during charging and discharging of Li-ion battery for electric vehicles. Appl Therm Eng, 2023, 218: 119239.

[19]	Ólafsson D, Vilaça P, Vesanko J. Multiphysical characterization of FSW of aluminum electrical busbars with copper ends. Weld World, 2020, 64: 59-71.

[20]	Ma ZY, Feng AH, Chen DL, et al.. Recent advances in friction stir welding/processing of aluminum alloys: microstructural evolution and mechanical properties. Crit Rev Solid State Mater Sci, 2018, 43(4): 269-333.

[21]	Kashaev N, Ventzke V, Çam G. Prospects of laser beam welding and friction stir welding processes for aluminum airframe structural applications. J Manuf Process, 2018, 36: 571-600.

[22]	Heider A, Stritt P, Weber R et al (2014) High-power laser sources enable high-quality laser welding of copper. In: Proceeding of 33rd international congress on applications of lasers and electro-optics (ICALEO 2014), San Diego, p 343–348

[23]	Daligault J, Dal M, Gorny C, et al.. Combination of Eulerian and ray-tracing approaches for copper laser welding simulation. J Laser Appl, 2022, 34: 042042.

[24]	Zhang L, Zhang G, Ning J, et al.. Microstructure and properties of the laser butt welded 1.5-mm thick T2 copper joint achieved at high welding speed. Mater Des, 2015, 88: 720-736.

[25]	Li H, Hsu E, Szpunar J, et al.. Deformation mechanism and texture and microstructure evolution during high-speed rolling of AZ31B Mg sheets. J Mater Sci, 2008, 43: 7148-7156.

[26]	Ali S, Shin J. Improvement in weld quality of Al and Cu joints using dual-beam laser welding. J Manuf Process, 2024, 119: 499-510.

[27]	Wei H, Elmer J, DebRoy T. Crystal growth during keyhole mode laser welding. Acta Mater, 2017, 133: 10-20.

[28]	Amine T, Newkirk JW, Liou F. Methodology for studying effect of cooling rate during laser deposition on microstructure. J Mater Eng Perform, 2015, 24: 3129-3136.

[29]	Thirathipviwat P, Song G, Jayaraj J, et al.. A comparison study of dislocation density, recrystallization and grain growth among nickel, FeNiCo ternary alloy and FeNiCoCrMn high entropy alloy. J Alloys Compd, 2019, 790: 266-273.

[30]	Shao J, Yu G, He X, et al.. Grain size evolution under different cooling rate in laser additive manufacturing of superalloy. Opt Laser Technol, 2019, 119: 105662.

[31]	Lee K, Rinker TJ, Tan C, et al.. Data-driven investigation of pore formation mechanisms in laser welding of Al-Cu. J Manuf Process, 2024, 124: 998-1009.

[32]	Agarwal G, Kumar A, Richardson IM, et al.. Evaluation of solidification cracking susceptibility during laser welding in advanced high strength automotive steels. Mater Des, 2019, 183: 108104.

[33]	Wang X, Wang HP, Lu F, et al.. Analysis of solidification cracking susceptibility in side-by-side dual-beam laser welding of aluminum alloys. Int J Adv Manuf Technol, 2014, 73: 73-85.

[34]	Lei Z, Cao H, Cui X, et al.. Analysis of welding solidification crack in narrow gap laser welding of high-strength steel. Int J Adv Manuf Technol, 2022, 119: 4177-4190.

[35]	Fang C, Wei J, Liu J. Solidification cracking sensibility of narrow gap laser welding on ITER-grade austenitic stainless steel. Fusion Eng Des, 2021, 162: 112068.

[36]	Phaoniam R, Shinozaki K, Yamamoto M, et al.. Solidification cracking susceptibility of modified 9Cr1Mo steel weld metal during hot-wire laser welding with a narrow gap groove. Weld World, 2014, 58: 469-476.

[37]	Li Y, Bushby AJ, Dunstan DJ. The Hall-Petch effect as a manifestation of the general size effect. Proc R Soc A, 2016, 472: 20150890.

[38]	Bishara H, Lee S, Brink T, et al.. Understanding grain boundary electrical resistivity in Cu: the effect of boundary structure. ACS Nano, 2021, 15: 16607-16615.