S-in motion^® for electric and hybrid vehicles

In the past ArcelorMittal has already developed S-in motion^® solutions dedicated to electric and hybrid vehicles. These projects are particularly relevant for carmakers who wish to create electric versions of their conventional vehicles.

In the electric S-in motion^® solution, the BIW was redesigned to accommodate the larger electric powertrain and battery protection required. Extensive use of AHSS (up from 35 to 58%) enabled ArcelorMittal’s engineers to reduce the weight of the electric BIW by 30 kg (11%).

ArcelorMittal’s S-in motion^® project has already demonstrated the potential of AHSS to lighten the body-in-white (BIW) and chassis of fuel-powered vehicles. But electric vehicles present a completely new set of challenges for automotive designers.

ArcelorMittal’s electric S-in motion^® solution:

• Provides lightweight solutions carmakers can implement today in their electric vehicles
• Has been adapted for a completely different powertrain
• Provides extra battery protection without adding mass
• Maintains crash performance
• Makes extensive use of AHSS to deliver weight savings.

ArcelorMittal has undertaken a study to determine how S-in motion^® solutions can be applied to a plug-in hybrid electric vehicle (PHEV). The S-in motion^® PHEV project identified the weight saving potential of advanced high strength steel (AHSS) on PHEV vehicle architecture.

An innovative body-in-white design and process changes can help to achieve weight savings at neutral cost, despite the heavier powertrain. The study also identified the challenges of converting a vehicle powered by an internal combustion engine (ICE) vehicle to a PHEV.

Hybrid powertrains present unique challenges for car designers. As well as accommodating a conventional internal combustion engine (ICE), the vehicle also has to carry a battery and electric motor.

This leads to

• Almost 200 kilograms to the weight of a typical C-segment vehicle
• Requires additional reinforcement in the body-in-white (BIW) structure

Weight saving thanks to increased use of AHSS

The S-in motion^® PHEV study showed that it was possible to decrease the BIW weight by increasing the use of AHSS (including hot stamped press hardened steels) to 57%, up from 37% in the baseline vehicle.

• The number of LWBs was more than doubled to 18 parts (up from 8).
• Hot stamping was utilised in 31% of the BIW (up from 6%). LWBs are an effective way to reduce weight while still maintaining performance by putting exactly the right steel in the right place.
• Press hardened steels (PHS) are utilised for 24 parts of the PHEV BIW, mainly Usibor^® and Ductibor^® . PHS offer high mechanical resistance for complex geometries without springback.

Meeting crash tests regulations

A significant challenge was ensuring that the optimised PHEV could meet the updated crash test scenarios. The pole crash test is one of the most difficult to satisfy as the PHEV has additional weight in the front (electric motor) and the back (battery pack). The solution was to make a hot stamped cross member from Usibor^® 1500. This offers outstanding protection against side impacts.