이종소재 Al/Cu의 레이저용접시 피치변화에 따른 용접 특성

Abstract

Recently, the paradigm of the automobile market is changing to eco-friendly vehicles according to carbon emission regulations. As the demand for eco-friendly vehicles increases, the importance of battery productivity and joint quality is being highlighted. Accordingly, laser welding was adopted as the lithium battery joining. However, strength and electrical resistance problems are emerging during single-weld seam laser welding. In order to overcome this problem, there is a method of increasing the joint area to improve strength and reduce electrical resistance. Therefore, many researchers are actively conducting research to overcome this through the development of various technologies. However, until now, the laser welding method according to the pitch variation of the weld seam and the weld seam has not been performed. Therefore, in this study, when welding dissimilar materials Al/Cu, the joint area was secured through multi-weld seam laser welding to improve the joint strength and reduce the electrical resistance to improve the quality of the welded part. In addition, in order to find out the characteristics of the welded part according to the pitch variation during laser welding, the reliability of the welded part was evaluated by considering the bead characteristics, mechanical and metallurgical characteristics, and electrical conductivity characteristics. As a result of the study, the maximum tensile-shear strength of 1.25 kN was secured in the multi-weld seam pitch 8 mm, and it increased by about 108% compared to the single-weld seam 0.6 kN. In addition, as a result of the electrical resistance test, the minimum electrical resistance of 77 μΩ was secured at the pitch 8 mm, and it was reduced by about 49% compared to the single-weld seam 115 μΩ.