EV battery crash protection requires that there is no intrusion into the battery pack — a particularly demanding challenge for the side pole impact test. Optimized profiles in UHSS steels enable an EV’s battery pack enclosure, cross members, and sills to work together to transfer and absorb crash forces to ensure the integrity of the battery cells.
One part of the Docol® EV Design Concept is to use 3D roll-formed beams in Docol® 1700 martensitic steel that are woven into a “mesh” structure for the bottom of a battery enclosure. The mesh structure maintains distance between the battery enclosure’s bottom plate and its tray, protecting the battery cells from intrusions coming in the Z direction.
The beams in blue are 3D roll-formed in Docol® 1700M. The profiles in the X-direction are the same as in Y-direction, but turned upside down to reduce the mesh’s height by a factor of two, enabling more leg room in the passenger compartment.
EVs must absorb more energy through their sills than ICE models due to the weight of the battery pack, the EV’s stiffer underbody, and the higher protection requirements for the battery. Extruded aluminum sill beams made from EN AW-6082 T6 are an efficient way of absorbing higher energy levels on side impacts – but at a premium price.
SSAB has run numerous simulations for 2D roll-formed sill beams made in Docol® CR 1700M steel, adjusting the wall thicknesses so each profile would weigh the same as the 6082-aluminum beam. The best 1700M profile had similar crash performance results as the 6082-aluminum beam.
Plotting force vs. displacement for nine different Docol 1700M profiles for EV sill beams. To see the profiles of the sill beams tested here, including the best performing profile, contact Docol.
EV cross members provide the battery pack with critical protection from side crash intrusions by transferring the impact force from one side of the car to its opposite side. To read a full description of our approach to optimized EV cross beams, including how we ran simulations to determine the best performing cross member profile, please see our Docol® EV Design Concept.
Leveraging the superior 2000MPa tensile strength of Docol® PHS 2000 steel, these newly developed cross members help protect the VW ID Buzz battery pack from side crash intrusions. Their 1.8 mm thickness contributed to the EV bus’s lightweighting goals while helping to deliver excellent crash test performance.
Impressive side impact test performance and lightweighting benefits made Docol® PHS 2000 steel a good fit for the VW ID Buzz bus.
In just one to two weeks, you can get trial samples of most of our commercially available AHSS/UHSS steel grades – plus some of our newest, not-yet-released steels.
Our steel grades serve specific design purposes and are chosen by designers for a wide range of automotive applications.