25 May 2023

Driving innovation in steel and empowering the shift to electric mobility: ArcelorMittal showcased its new multi-phase ultra high strength steel grades as well as its ArcelorMittal Multi Part Integration™ technology and steel solutions for battery enclosures at Great Designs in Steel (GDIS). GDIS is the largest gathering of automakers, suppliers, R&D teams and academia in Michigan, North America.

ArcelorMittal showcased a catalogue of design solutions for Battery Electric Vehicle (BEV) Battery Enclosures adapted for the North American market. We also unveiled new multi-phase steel grades and ArcelorMittal Multi Part Integration™ solutions to simplify vehicle design and production. Together, these offerings support automakers as they shift from internal combustion engines (ICE) to battery electric vehicles (BEV).

Steel is Strongest Defense for Battery Enclosures

The battery enclosure is one of the most vital parts of the BEV, serving as its shield. Its role is critical — and strength is king. It must protect what’s inside – the battery cells, electrical and electronic systems, and cooling system. It also shields battery components from external elements such as dust, debris and moisture.

The enclosure must be strong enough to prevent intrusion into the space during a crash event — something that Usibor^® and our MP steel grades are uniquely equipped to handle. If the enclosure does deform, it must absorb the crash energy. A strong battery enclosure keeps the vehicle and passengers safe from battery damage, thermal runaway, fire, fumes and electromagnetic fields.

 Steel offers many advantages over competing materials, including:

• Strength: Steel can withstand a lot of force compared to other materials, making it the best choice for protecting the battery from damage in a crash event.
• Durability: Steel can withstand severe vibrations from rough road conditions, elements of varying climates, and the wear and tear of everyday use.
• Design fit efficiency: Steel’s high strength and formability allows steel structures to meet functional requirements while occupying less space.
• Manufacturability: Steel is very formable and can be manufactured to fit within the tight package of an electric vehicle. Steel is easier to weld and assemble into its final form. And, the large industry competence and know-how in manufacturing steel components and assemblies enables a seamless manufacturing launch.
• Repairability: Steel can be easily repaired if damaged, making it a good choice for battery enclosures that are exposed to harsh conditions such as offroad use, large road debris, and misuse situations.

Delivering What Automakers Need

Real estate in a vehicle’s underbody is a critical aspect that automakers focus on to improve the available space for battery cells. ArcelorMittal has been working closely with the industry to identify the most efficient design solutions for battery enclosures.

Currently, most Multi-Phase automotive standards go up to 1200 MPa tensile strength (TS). ArcelorMittal has extended Multi-Phase grade strengths to 1300 and 1500 MPa (TS), and is targeting development of MP1700.

In addition to increased strength, ductility and elongation, another attribute automotive manufacturers demand is flatness. When an incoming material doesn’t have sufficient flatness, the shapes are less likely to fit dimensional requirements of the component. This means they will fail to properly fit together in final assembly. Not only is ArcelorMittal pushing the limit on strength with our latest MP steel grades, we’re also delivering on customer requirements for flatness.

“Flatness is often taken for granted, but not easy to achieve,” added Lepre. “The ability to deliver on high bendability, strength and flatness sets ArcelorMittal apart from the competition and helps customers build stronger, safer and more efficient systems.” 

Consolidation of Parts through Partnership

In addition to battery enclosures and new steel grades, ArcelorMittal offers yet another solution for automakers, particularly those interested in part consolidation - ArcelorMittal Multi Part Integration™ (MPI).

Using ArcelorMittal’s press hardenable steels (PHS), ArcelorMittal Tailored Blank’s industry-proven laser-welding solutions combine multiple parts into one single hot stamped part.

ArcelorMittal’s PHS portfolio includes grades that range in strength from 500 MPa (Ductibor^® 500 and 1000) with high ductility and energy absorption capabilities, to 2000 MPa (Usibor^® 1500 and 2000) for anti-intrusion applications. ArcelorMittal continues to develop other products in the PHS family aiming to further productivity improvements.

Part consolidation simplifies production for the automaker by significantly reducing the number of joining operations. This results in quicker assembly time and cost savings of up to 10 per cent. As proven by several existing door ring applications, MPI concepts offer high flexibility in tuning thickness and grade within a part. They also achieve a highly repeatable and robust crash and structural performance. Such design optimization also allows for highly efficient material utilization. This directly contributes to increased sustainability of the vehicle. 

Every year GDIS brings leaders in the industry together to share incredible advances in steel, and 2023 was no exception. The knowledge we gain and share is invaluable. It shows we must keep collaborating to inspire and challenge each other. Together, we can contribute to more efficient transportation era and a greener environment.