Aluminum has been used in sports cars for decades. Now the material is literally making light work of mid-range cars too, and electric cars are virtually unthinkable without aluminum. In addition to its low weight, the 100 percent recyclable metal also scores points for increased range, CO₂ savings, and safety aspects.
Bianca Richle, June 2023
From zero to one hundred in four seconds. Fast acceleration like this is only possible if a sports car is lightweight. Consequently, high-performance vehicle manufacturers have been using aluminum for decades. Luxury car manufacturers have embraced the use of aluminum since the 1990s to increase efficiency and performance. They make the axle area, auxiliary parts, and structural components out of aluminum to reduce weight. The engine and transmission housing is cast from aluminum in the majority of cars today – for both internal combustion engine and electric drive systems. In principle, it’s possible to build the entire vehicle, including the structure and body panels, from aluminum. Some electric vehicle (EV) manufacturers are already doing this. In the future, the trend toward aluminum will continue to grow, primarily due to increasing electrification. “An aluminum chassis is especially suited to EVs. Thanks to its lower weight, you can reduce the battery size and achieve the same level of performance,” says Dr. Thomas Rudlaff, Managing Director of Alumobility.
Alumobility is a global initiative of leading aluminum and downstream technology partners, providing technical studies and thought leadership. Alumobility aims to help deliver on the promise of lighter, more efficient, and more sustainable mobility. “The whole issue of efficiency is bringing aluminum more and more into the forefront,” Dr. Rudlaff explains. It’s also why Tesla, as well as all the newcomers to the EV market, are now using aluminum almost exclusively. For established carmakers, the change is a bit more difficult, as it requires them to convert part of their production process.
The whole issue of efficiency is bringing aluminum more and more into the forefront.
Dr. Thomas Rudlaff, Managing Director of Alumobility
Efficiency is not the only reason in favor of lightweight construction with aluminum. “Lightweight cars handle better, which is especially evident when cornering,” Dr. Rudlaff says. “And secondary objects such as tires or brakes can also be built lighter since they don’t have to support as much weight.”
A lightweight car saves about 100 kilograms of weight compared to a conventional car. Energy absorption is also important. “Aluminum absorbs more energy than steel when it folds. That’s why many crash management systems are already made of aluminum,” says Dr. Rudlaff. This is decisive for electric cars, as the battery must remain protected at all costs in the event of a collision. The properties of aluminum are highly favorable for vehicle construction and are often underestimated. “People think aluminum is soft, but in hailstorms, for example, aluminum performs better than steel.”
Aluminum has two characteristics in common with all other metals: first, it is 100 percent recyclable and second, it can be remelted any number of times. About 75 percent of the aluminum ever produced is still in circulation. “Aluminum has the advantage of having a lower melting point than steel,” Dr. Rudlaff says. This pays off during recycling. When aluminum is recycled, it requires only 5 percent of the energy used in primary production, so the use of secondary aluminum is very worthwhile. Low CO₂ values of up to 0.5 kilograms of CO₂ per kilogram of aluminum can be achieved.
Who: Alumobility
Where: Global, founded in Zurich, Switzerland
When: Founded in 2021.
What: Alumobility is a global ecosystem of leading aluminum and enabling downstream technology partners. Through technical studies and its thought leadership, Alumobility aims to help fulfill the promise of lighter, more efficient, and more sustainable mobility.
Members: Alumobility’s members include the aluminum producers: Constellium, Novelis, Speira, Magna, ARO, Atlas Copco, fischer group, and Sika.
An aluminum chassis is especially suited to electric vehicles. Thanks to its lower weight, you can reduce the battery size and achieve the same level of performance.
Dr. Thomas Rudlaff, Managing Director of Alumobility
The use of primary aluminum also makes a lot of sense if sustainably produced aluminum is used for this purpose. Aluminum produced with renewable energy achieves a footprint of 4 kilograms of CO₂ per kilogram of aluminum. If the CO₂ quantification is below 8 kilograms per kilogram of aluminum, production is more sustainable than steel.
“Aluminum makes the vehicle lighter. For internal combustion engines this means that the efficiency of the energy balance is better, which means lower fuel consumption,” Dr. Rudlaff says.
For electric vehicles, energy consumption also decreases sharply when vehicles are lighter. For example, for a vehicle with an unladen weight of 1,600 kilograms compared to a vehicle with an unladen weight of 1,500 kilograms, the lighter vehicle saves approximately 1 kilowatt hour per 100 kilometers. This means that the battery could be 6 percent smaller to generate the same range.
Making the battery smaller is worthwhile financially, as its raw materials and production are very cost-intensive, and it also has a positive impact on the carbon footprint because the smaller battery is much less resource intensive. “The beauty is that you get the same acceleration performance with a smaller battery,” says Dr. Rudlaff.
The aluminum body can either be manufactured using sheet metal construction or die cast. “The advantage of die casting is that many functions can be combined into one component. This allows me to reduce the components, which is promising for production,” says Dr. Rudlaff. “In addition, I can plan my parts according to weight distribution.
This is more difficult and costly with sheet metal construction. Die casting can be customized precisely according to calculations, which is appealing in terms of construction. You can calculate where to put loads, use a die-cast part, and if I already have one, how I integrate other components.”
It remains exciting to see how the industry will continue to develop. But for Dr. Rudlaff, one thing is clear: “The future is electric, and the future is aluminum.”
As Managing Director, Dr. Thomas Rudlaff is responsible for Alumobility’s strategy and governance, including promoting the organization’s mission and expansion of the ecosystem through new members and partners.
A former engineering executive with Mercedes-Benz and Audi, Dr. Rudlaff brings more than 30 years of experience designing and developing lightweight vehicle structures to Alumobility. He has led multiple projects to launch fully aluminum vehicles, including the first aluminum-intensive vehicle at Mercedes-Benz. In addition to making vehicles safe and reliable, he is passionate about creating cars that are fun to drive, yet more sustainable for the environment. Earlier in his career, Dr. Rudlaff led an association dedicated to manufacturing technology. He has also been a regular contributor to industry organizations, including Automotive Circle.
Dr. Rudlaff holds a degree in physics from the University of Kaiserslautern, Germany, and a PhD in laser technology from the University of Stuttgart, Germany.
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