Electric vehicles (EVs) are becoming more common, especially in countries like Norway.
However, these cars contain a lot of heavy electrical wiring, which affects their energy efficiency and driving range.
Now, researchers from NTNU (Norwegian University of Science and Technology) are working on a solution—replacing copper wiring with aluminum to make EVs lighter and more efficient.
Why replace copper with aluminum?
For years, copper has been the preferred material for electrical wiring because it has excellent conductivity, strength, and flexibility.
But there’s one big drawback—it’s heavy. The weight of copper wiring in an EV contributes significantly to the car’s total mass, reducing its efficiency and range.
Aluminum, on the other hand, is:
✔ Much lighter than copper, reducing the overall weight of the vehicle.
✔ A good conductor when mixed with the right alloys.
✔ Flexible and strong enough for electrical wiring when properly processed.
By replacing some of the copper wiring with aluminum, EVs can become lighter, use less energy, and drive farther on a single charge.
The challenge is that pure aluminum is weaker than copper and doesn’t conduct electricity as well. To solve this, Ph.D. researcher Jørgen A. Sørhaug and his team at NTNU have developed hybrid wires made from both copper and aluminum.
“In our project, we have produced hybrid electrical conductors made from copper and aluminum through welding, which we have then tested and studied in great detail,” Sørhaug explained.
One of the biggest hurdles in joining copper and aluminum is heat. When welded at high temperatures, the two metals form brittle crystals that reduce conductivity and strength.
To avoid this problem, the researchers used a method called Hybrid Metal Extrusion & Bonding (HYB), a cold welding technique developed at NTNU.
✅ Cold welding bonds copper and aluminum at the atomic level without high heat.
✅ The process prevents the formation of brittle crystals, keeping the wires strong and conductive.
✅ The result is a more efficient, lightweight conductor for EVs and other electrical applications.
Although cold-welded aluminum-copper wires show great promise, more research is needed to make aluminum as strong as copper. Scientists are experimenting with alloys, which mix aluminum with other elements to improve its strength and durability.
“But aluminum alloys are often sensitive to high temperatures,” Sørhaug explained. “We are investigating how to make aluminum stronger while keeping its lightweight benefits.”
NTNU and SINTEF, along with industry partners like Hydro ASA and Corvus Energy AS, have launched a new project to further improve cold-welded aluminum-copper wiring.
Professor Randi Holmestad, one of Sørhaug’s supervisors, said, “By optimizing the welding process, we can improve both strength and conductivity, making aluminum-copper wiring even more useful for electric vehicles.”
If successful, this research could lead to lighter, more energy-efficient EVs, helping to make electric transportation more sustainable and efficient in the future.
