How automakers can boost EV range and affordability: The future rides on aluminum

Aluminum can play a crucial role in automakers’ efforts to increase the range of electric vehicles by reducing their weight. Aside from being lighter than steel, aluminum also can help streamline manufacturing processes, doesn’t rust and is easier to recycle and more sustainable. Here Mark White, Technical Director at Alumobility, a non-profit association devoted to advancing the use of aluminum in auto manufacturing, explains the many other strategic advantages gained by replacing steel with aluminum.

Q: As the market for battery electric vehicles (BEVs) continues to grow, what are some of the main issues for automakers?
 

Mark White: One of the key considerations for electric vehicles is, of course, range. The other is cost, as automakers still are looking for a way to make BEVs more affordable. Aluminum solves both problems, notably through light-weighting. Because aluminum has one-third the density of steel, an aluminum body weighs up to 45 percent less than an equivalent steel one. Automakers know that minimizing vehicle weight is the key to efficiency; Henry Ford himself said that weight is the enemy of performance. Lighter vehicles simply require less energy to do the same job, so lighter BEVs can travel further with the same batteries or go the same distance with fewer batteries.

As Alumobility’s Last Mile Delivery Vehicle study showed, a lighter aluminum-intensive vehicle (AIV) also provides greater payload and towing capacity, even with a smaller battery pack. This creates a virtuous circle of light-weighting, with secondary weight savings such as smaller motors, brakes and suspension parts that still provide the same performance, range and acceleration. Fewer batteries mean faster charge times for the same amount of range, reductions in required raw materials and mining and lower emissions. Not only are batteries heavy, they also are the most expensive part of a BEV. Overall, it costs much less to lightweight a vehicle with aluminum.

Q: How does Alumobility work with auto manufacturers to test these claims?
 

White: We cooperate with them in theoretical case studies. As part of these, we have replaced steel with aluminum in areas like the closures, the body, the battery box and chassis systems, not only to demonstrate the weight savings possible on these systems, but also to demonstrate other benefits, including the potential for secondary weight reductions and related cost savings for automakers. For example, in our Last Mile Delivery Vehicle study, we reduced the battery size by 6kWh for the same range, while in the Hyundai Genesis GV70 BEV Bodyless Doors study, we reduced manufacturing complexity.

Q: It’s commonly believed that a heavier vehicle is safer than a lighter one. Is that an issue for aluminum?
 

White: I believe lighter cars are actually safer. They typically handle better. They accelerate, turn and brake more quickly and they are more stable, due to a lower center of gravity, which helps to avoid accidents in the first place. Aluminum also performs better than other materials in the event of an accident. It absorbs more energy than steel for the same weight, which results in less intrusion into the passenger safety cell.

Moreover, aluminum is not just strong and safe, it’s also very durable and won’t corrode the same way steel does. When something hits or dents an aluminum body, the metal naturally reforms a protective oxide layer, which prevents it from rusting. And thanks to its lighter weight, an AIV puts less wear and tear on other vehicle systems, such as tires and brakes. This further reduces potential emissions and the impact on the environment.

Q: Will automakers whose manufacturing processes revolve around steel have to retool their equipment to build AIVs?
 

White: While steel-intensive vehicles (SIVs) are generally manufactured from stamped sheet, aluminum vehicles can be made from a combination of stamped sheet, extrusions, rolled form parts and castings – and with fewer parts overall. Normally, an AIV body will require around 20 percent fewer parts and joints compared to an SIV body. As such, when they make AIVs, automakers require fewer tools, robots, joints and sealers; use less energy; and generate fewer factory emissions. The end result? Less capital investment as well.

Not only is manufacturing an AIV less complex, but automakers generally need less than 0.6 kilograms (about 1.3 pounds) of aluminum for every kilogram of steel. With less material and fewer parts, AIV production creates a better working environment. In addition, Alumobility AIV studies show that a typical AIV body needs up to 50 percent less gauge and grade combinations, which reduces the amount of inventory in press and body shops. As such, there’s less material to purchase and store and the production process is leaner.

The only real major change in manufacturing occurs when steel bodies are joined, using mainly resistance spot welding. AIV bodies can use a combination of self-piercing rivets, resistance spot welding and adhesive bonding to reduce the total number of joints needed. When combined with the part-count reduction, this can improve production efficiency while reducing floor space and equipment requirements. To decrease the impact of manufacturing changes, automakers typically switch from SIVs to AIVs when they introduce new models. The press shop, paint shop and general vehicle-assembly processes require only minor changes when switching from SIVs to AIVs.

Q: Producing primary aluminum is very energy intensive. Could this create a barrier to greater adoption in the industry?
 

White: One great thing about aluminum is that it can be recycled over and over again without the need for downcycling or a loss in performance or quality. As a result, it can play a major role in the industry’s efforts to reduce emissions. Aluminum recycling requires only around 5 percent of the energy compared to producing new material. And aluminum melts at 650 degrees Celsius (1,202 degrees Fahrenheit), as compared to steel, which melts at around 1,400 degrees Celsius (2,552 degrees Fahrenheit), so at least 30 percent less energy overall is required to recycle an equivalent aluminum vehicle body.

Furthermore, aluminum can be recycled much earlier than at the end of the vehicle’s life by implementing closed-loop recycling in the parts-production process. This involves segregating any aluminum scrap from the process and sending it back to the material supplier for re-use. Several automakers already use this process to reduce manufacturing waste, emissions and costs; Alumobility published a study about it as part of the Circular Car Initiative last year.

When we analyze different vehicles’ sustainability, it’s not just a ton-to-ton comparison, but the impact over their entire life cycle. Superior recyclability is one of aluminum’s great environmental advantages. Moreover, lightweight vehicles are more environmentally friendly in every phase of their life cycle.

For BEVs, as batteries get smaller, so do emissions, not to mention fewer rare minerals are needed for manufacturing. Additionally, there are fewer batteries to dispose of at the end-of-use phase. Aluminum is definitely the material of choice as we move towards the circular economy.

ABOUT THE PANELIST
Mark White
Technical Director, Alumobility
Mark White provides strategic guidance to the technical work streams, overseeing Alumobility’s studies and related partnerships and presenting them at various conferences and events.
With more than 30 years of automotive experience, predominately at Jaguar Land Rover, White has held a variety of leadership roles in body engineering, design, research, vehicle manufacturing processes and electrification.
To learn more about Alumobility, visit: www.alumobility.com.