Electric Vehicle Battery Energy, Emissions and Range Savings - The Power of Recycled Aluminum

The automotive industry, more precisely the production of electric vehicles, pioneered an innovative process for collecting and processing scrap aluminum for new vehicle parts. DOE's Pacific Northwest National Laboratory, in collaboration with mobility technology company Magna, has just revealed a new manufacturing method that reduces the energy input by more than 50 % and carbon dioxide emissions for more than 90 %, thus eliminating the need to extract and process the same amount of raw aluminum ore. In addition, the use of light aluminum can also increase the driving range of electric vehicles.

This patented and award-winning Shear Processing and Extrusion (ShAPE) process collects scrap pieces and aluminum trim scraps from automotive manufacturing and directly converts them into suitable material for new vehicle parts. Soon they will also be ready for the production of light aluminum parts for electric vehicles.

The latest advances, detailed in a new report and research article in Manufacturing Letters, eliminate the need to add freshly mined aluminum to materials that will be used in manufacturing. By reducing the cost of aluminum recycling, manufacturers can lower the overall cost of aluminum components and thus provide them with better alternatives to replace steel in production.

"We have shown that aluminum parts made using the ShAPE process meet automotive industry standards for strength and energy absorption," said Scott Whalen, PNNL materials scientist and lead researcher. "The key is that the ShaAPE process breaks down the metal particles into waste without requiring an energy-intensive heat treatment step. This alone saves a lot of time and introduces new efficiencies."

The new report and research publications are the culmination of a four-year partnership with Magna, the largest auto parts manufacturer in North America.

"Sustainability is at the forefront of everything we do," said Massimo DiCiano, Head of Materials Science at Magna. "From our production processes to the materials we use and the ShAPE process is an excellent proof of the direction in which we want to develop and create new sustainable solutions for our customers."

Advantages of aluminum

Apart from steel, aluminum is the most used material in the automotive industry. Lighter and stronger aluminum is a key material in the strategy to produce lightweight vehicles for improved performance, whether to increase the range of an electric vehicle or reduce battery capacity. While the automotive industry currently recycles most of its aluminum, it regularly adds newly mined primary aluminum to it before reuse to keep the grade the same.

Metal fabricators also rely on the century-old process of preheating bricks, or "bills" as they are known in the industry, to temperatures above 550 °C more ed. A preheating step dissolves clusters of impurities such as silicon, magnesium, or iron in the raw metal and distributes them evenly throughout the billet through a process known as homogenization.

In contrast, the ShAPE process performs the same homogenization step in less than a second and then, without preheating, transforms solid aluminum into the final product in minutes.

"Together with our partners at Magna, we have reached a key milestone in the development of the ShAPE process," said Whalen. "We have demonstrated its versatility by creating square, trapezoidal and multi-cell parts, all of which meet quality criteria for strength and 'ductility', or the ability to deform."

For these experiments, the research team worked with an aluminum alloy known as 6063, or architectural aluminum. This alloy is used for various automotive components such as engine mounts, bumper assemblies, frame rails and exterior trim.

The PNNL research team examined the extruded shapes using scanning electron microscopy and electron backscatter diffraction, which creates a picture of the placement and microstructure of each metal particle in the final product. The results showed that ShAPE products are equally capable and do not have manufacturing defects that could cause parts to fail. The products had no signs of large groups of metal particles that can cause material deterioration and hinder efforts to use secondary recycled aluminum to make new products.

Now the research team is looking at even stronger aluminum alloys, which are commonly used in battery cases for electric vehicles.

"This innovation is just the first step toward creating a circular economy for recycled aluminum in manufacturing," said Whalen. "We are now working on including post-use waste streams, which could create a whole new market for secondary scrap aluminum."