In-depth evaluation of laser welding of thick busbar to 21700 Li-ion cell terminal for electric supercar vehicle battery pack

High-performance supercars using Li-ion batteries necessitate thicker aluminium busbars with thin steel joints. However, joining these materials often leads to overheating resulting in brittle intermetallic compounds (IMCs), reduced weld quality, and higher electrical resistance. This study evaluate...

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Bibliographic Details
Published inJournal of materials research and technology Vol. 33; pp. 3058 - 3067
Main Authors Kumar, Nikhil, Pamarthi, Venkat Vivek, Moffat, John, Masters, Iain
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.11.2024
Elsevier
Subjects
Electric vehicle (EV)
Intermetallic compound formation
Laser welding
Li-ion battery
Weld resistance
Electric vehicle (EV)
Weld resistance
Laser welding
Li-ion battery
Intermetallic compound formation
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Summary:High-performance supercars using Li-ion batteries necessitate thicker aluminium busbars with thin steel joints. However, joining these materials often leads to overheating resulting in brittle intermetallic compounds (IMCs), reduced weld quality, and higher electrical resistance. This study evaluated, laser wobble welding of a nickel-plated Al busbar of 0.9 mm thickness with a 0.3 mm thin 21700 cell nickel-plated steel terminal. An optimised joint using the wobbling method is implemented for the direct application to battery packs, satisfying the current carrying capacity with minimal electrical resistance and enhanced weld quality was generated. Elemental and microhardness analysis revealed the mechanism of IMC formation and observed that the brittle and therefore detrimental Fe2Al5 IMC predominantly forms near the protruding interface between Al-Fe solid solutions.
ISSN:2238-7854
DOI:10.1016/j.jmrt.2024.10.012