배터리 소재 구리-알루미늄의 그린 레이저 용접성에 관한 연구

• Published in: 대한금속·재료학회지, 62(10) Vol. 62; no. 10; pp. 757 - 765
• Main Authors: 유현종, Hyun Jong Yoo, 김명진, Myung Jin Kim, 강희신, Hee Shin Kang
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 05.10.2024; 대한금속·재료학회
• Subjects: Aluminum; Electric vehicle; Green laser; Intermetallic compound; Nickel coated copper; 재료공학
• ISSN: 1738-8228; 2288-8241
• DOI: 10.3365/KJMM.2024.62.10.757

Copper is widely utilized in electric vehicle batteries due to its excellent electrical conductivity, lightweight, and excellent corrosion resistance. However, copper has a high reflectivity of about 97% for infrared lasers, which makes it difficult to achieve stable welding quality. This study investigated using a green laser to weld nickel-coated copper and aluminum materials. After performing welding by changing the laser power and scan speed, the weld cross-section was observed with an optical microscope, and it was confirmed that the welding penetration depth and bead width increased as the heat input increased. The spatter on the bead surface and defects such as pores and cracks in the weld were caused by excessive heat input. Analysis of the weld cross-section using SEM-EDS showed that high heat input increased the formation of intermetallic compounds including CuAl2 and Cu9Al4. The mechanical properties of the weld were examined using a shear tensile test. The analysis results showed that intermetallic compounds caused brittleness in the weld joint, which lowered mechanical properties and caused defects such as pores and cracks. P60 (1.2 kW, scan speed: 250 mm/s), P80 (1.6 kW, scan speed: 375 mm/s), and P100 (1.2 kW, scan speed: 375 mm/s) were examples of excellent mechanical quality. The fastest welding condition, P100 (power: 2 kW, scan speed: 450 mm/s), was suggested as the most efficient welding condition.