A new $2-million project at the University of Michigan aims to develop easier and more cost-effective ways to make recyclable lightweight automotive sheet metals. “The Clean Sheet Project” seeks to develop new design tools and establish best practices for material producers and carmakers with a focus on recycling from start to finish in production.

We need to reduce the environmental impacts of vehicle production going forward, and one of the ways to do that is to boost the production of these lightweight sheet metals from recycled materials. Not only will that reduce emissions from the automotive production process, it will also help to limit destructive mining for raw materials.

We already recycle many of the materials that are going into these new vehicles, but we don’t do it well. It requires putting the steel and aluminum into electric arc- or gas-fired furnaces, and then casting new metal.

—Daniel Cooper, U-M assistant professor of mechanical engineering and project leader

The recycled metal products aren’t high quality because it’s difficult, if not impossible, today to obtain pure source material to melt down. In the US, there is little demand for these contaminated scrap metals, so the materials are often shipped to other countries where low-paid workers sort them by hand.

Recyclers use mechanical shears to try to break apart and pile up the different metals to send separately to furnaces. However, vehicles contain many different metal alloys that are mixed together as they are broken up, and aluminum car panels often have steel rivets that are difficult to remove, even with magnets.

This task of separating the metals is only getting more difficult. Electric vehicles, for example, use even more copper wiring in their electronics. Recycled steel can crack during manufacturing if it contains as little as 0.1% copper. Typically, the recycled metal ends up being used in places with low performance requirements such as aluminum castings in engine blocks and steel reinforcing bars.

We see tremendous opportunity for increased material reuse and recycling if vehicle designs include ease of disassembly, improved material separation and industrywide commonization. The Clean Sheet Project will provide these insights and we are excited to join the University of Michigan and other partners in participating. This work strongly supports Ford’s commitments to reduced CO₂ emissions, developing a circular economy and a carbon neutral future.

—George Luckey, manager of stamping and alloy development at Ford Research and Advances Engineering

Ford is among several private funding partners involved in the effort.

Two factors suggest that establishing how to make more sustainable practices commonplace in needed now.

The first is the growing commitment to electric vehicle manufacturing by major automakers. The second factor is that over the next few years, a wave of aluminum-sheet intensive vehicles will reach their end of life and make their way to scrap yards.

In a paper published this year, Cooper and his team found that four vehicles—the Ford F-150, Super Duty, Expedition, and Lincoln Navigator—account for around 1,200 kt of aluminum automotive body sheet (ABS) embedded within the 2020 US fleet.

The aluminum ABS intensive construction of these vehicles presents a unique opportunity to U.S. recyclers. If production continues at the current volumes, aluminum ABS scrap from these vehicles will increase to approximately 125 kt/year in 2035 and 246 kt/year in 2050. The majority of this scrap will be available for U.S. processing with <<10% of deregistered vehicles exported or achieving vintage status. For comparison, only 121 kt of aluminum auto shred (containing negligible aluminum ABS) was domestically consumed in the U.S. in 2017.

—Zhu et al.

Zhu et al.

This calls for a reinvention of how such high-value materials can be recycled or remade to produce new vehicles. Aluminum is known for being tricky to recycle without a loss of performance, and you can see why some people are getting nervous about where we’re heading. If we are switching to EVs, that probably means even greater demand for high-quality aluminum and a loss of the internal combustion engine market that currently uses a lot of the low-quality recycled metal.

—Daniel Cooper

Previous efforts at making EV components more readily recyclable have seen some success, but the lack of an integrated approach across the industry from material producers and recyclers to carmakers and scrap processors has hurt the effort.

Hopefully, our methodology could provide a breakthrough across the board.

—Daniel Cooper

That methodology includes integrated computational materials engineering modeling that will determine how well mixed metals can be recycled. These models can help researchers discover new materials that are more recycling-friendly and determine how more recycled materials can be used in high-quality components like aluminum car bodies. Additional modeling will assess vehicle design options, such as what and where materials are used.

Researchers will also analyze new technologies for disposing of old vehicles and separating the materials. The project will deliver a new suite of designs for recycling tools and technology roadmaps for the whole industry.

The Clean Sheet team is currently organizing a cross-sector workshop on automotive metal sheet design, production, manufacturing and recycling in order to learn from industry experts on the opportunities to increase high-quality metal sheet recycling.

Roughly half of the project funding comes from the US Department of Energy’s REMADE Institute—a public-private partnership that promotes sustainable technology adoption for industries. Along with Ford, additional funding partners include: Novelis, The Institute of Scrap Recycling Industries, The Aluminum Association, Light Metal Consultants and Argonne National Laboratories.

Resources

• Yongxian Zhu, Laurent B. Chappuis, Robert De Kleine, Hyung Chul Kim, Timothy J. Wallington, George Luckey, Daniel R. Cooper (2021) “The coming wave of aluminum sheet scrap from vehicle recycling in the United States,” Resources, Conservation and Recycling, Volume 164, 105208, doi: 10.1016/j.resconrec.2020.105208.