A review of laser welding for aluminium and copper dissimilar metals

Dissimilar metal composite structures have been used in a wide range of applications to meet the requirements of lightness, corrosion resistance, electrical conductivity, and thermal conductivity due to their excellent overall performance. With the global energy conservation and emission reduction policies, dissimilar aluminium (Al) and copper (Cu) for lithium battery welding are more and more discussed. Laser welding is a unique technology for Al and Cu due to its high energy density, precise control, ease of automation, and remote welding. However, high reflectivity and differences in material properties result in poor laser absorption and an unstable welding process. Furthermore, sufficient mixing of Al and Cu during the welding process tends to form brittle intermetallic compounds (IMCs). This paper discusses the laser welding and the challenges faced by joining Al/Cu dissimilar metals, and analyzes the effect of different process parameters and laser output modes on the weld joint. Furthermore, the research progress on filler metals and process monitoring are discussed.