Electroplating of Aluminium and Copper for Reliable Electrical Connections for Power Electronics

Abstract:
For weight and cost reasons, the aluminium content of cars is increasing since decades. For electric vehicles it might become interesting in the future to use the same advantages to replace heavy and expensive copper bus bars for power electronic applications. In a study, performed at Inovan, friction and bending tests showed comparable results for samples of aluminium and copper alloys. Hence aluminium may be a suitable base material for power electronics. Joined with copper, e.g. as a clad Al/Cu-composite, it allows many opportunities in the field of battery technology or cell connectors. An improved electroplated corrosion protection provides reliable interfaces and technological advandages for joining technologies, like screwing, ultrasonic welding, or ribbon bonding. Approved conventional solutions still depend on copper and its alloys. To enhance the long term stability of such metals, new, nm-thin corrosion protection layers were investigated. Comparison to thicker layers was done by bondability (using the new BAMFIT-method), resistance measurement and a wear test. Its been shown that for many usecases in joining those nanometer layers can be applied to reduce more costly, thicker precious or unprecious electroplating.