Characteristics of resistance projection–welded aluminum-copper interconnects

Abstract

This paper describes the use of resistance projection welding of lap joints between tinned copper terminals with flat aluminum conductors. With the exception of resistance brazing, resistance welding, which has been established for many decades, is currently not used for joining dissimilar metal joints made of copper and aluminum. The use of this technology could potentially result in particularly cost-effective joints that are easily scalable to different sizes of terminals. For the necessary current density during the welding process, a mechanically embossed welding projection in the copper conductor surface is required. During the welding process, the projection moves into the softer aluminum material without being deformed. The projection expresses part of the brittle liquid intermetallic compounds produced. Shear tensile tests, electrical conductivity measurements and micrographs are used to assess the technical properties of the joint. The presented results show that the created intermetallic joint has good electrical and mechanical properties despite pronounced intermetallic AlCu layers.