Historically aluminum was recognized as a valuable material to achieve weight reduction targets in engines, vehicle chassis and suspension. Aluminum needs to be also considered in new areas like vehicle electrification to support the overall weight reduction targets. The use of aluminum helps to improve fuel economy and brings down CO2 emissions by reducing weight. This benefit is an attractive option for the wiring harness to replace heavier copper conductors. In addition to large cross section wires for power cable, where aluminum conductors are already in use, the intermediate aluminum cable cross section of 2.5mm2 to 6.0 mm2 provides a good potential for car implementation to hit weight saving targets.
The major implementation roadblocks for aluminum technology are the surface oxides Al2O3 which are an insulator and the potential galvanic corrosion of aluminum in combination with the always present copper terminal. Galvanic corrosion can occur with the presence of electrolyte fluids inside the car. Traditional termination solutions are mostly dependent on the use of additive materials like paints, grease or similar approaches to protect the aluminum at the crimp area. To achieve a permanently reliable electrical contact, the termination technology between a copper terminal and aluminum wire with single strands, needs to be specifically optimized.
Delphi now provides a technology named SMC (Selective Metal Coating). SMC is an innovative technical solution for a wiring harness equipped with aluminum cable.