Dissimilar laser welding of aluminium and copper alloys

TWI worked for its members to solve the technical problems of joining aluminium to copper using laser welding technology. An increasing number of enquiries over the past two years from members asking for support in this area led to the successful development of a high-speed laser-technology-based solution.

An increase in manufacturing demand in the automotive industry, for example, for products with high capacity battery cells is leading to interest in the technical solutions. High capacity battery cells use aluminium and copper, as the anode and cathode terminals respectively, to improve electric current flow and boost a vehicle’s performance. Existing electrical connection joining technologies, such as ultrasonic welding and the use of direct conductive adhesives, are deemed too slow for the high demand in a manufacturing situation.

Laser welding is considered an attractive process to industry due to its high processing speed and highly repeatable, fully automated, process. However, laser welding of copper to aluminium presents several challenges. Because of the high surface reflectivity and thermal conductivity of copper, and the poor miscibility of aluminium and copper, keyhole instability and brittle intermetallic formation are common issues found when laser welding these metals. Read more: TWI.