Stainless Steel Could Make EV Batteries Up To 20% Lighter


Finnish material experts from Outokumpu, along with scientists from Germany’s Fraunhofer Institute for Laser Technology, are working on lightweight, high-strength stainless steel solutions for electric vehicle (EV) battery packs that are 20% lighter than conventional packs.

This new battery pack design combines several lightweight engineering technologies, as well as new types of cooling and structural strategies. The Forta H1000 austenitic, ultra-high-strength stainless steel from Outokumpu enables the implementation of structural lightweight engineering initiatives while providing a high level of safety.

“A high capacity for energy absorption and increased stiffness with thinner wall thicknesses are crucial characteristics for the development of future lightweight designs in automotive engineering,” says Stefan Lindner, senior technical manager for the automotive segment at Outokumpu. “The Forta H-series fulfills these requirements.”

“With Forta H1000, we were able to engineer a safer casing despite its leaner structure and thus save a considerable amount of weight,” says Paul Heinen, head of the FSEM II Project at the Institute for Laser Technology. “Using 1.2-millimeter-thick sheets instead of 1.5-millimeter wall thickness allows a weight reduction of about 20 percent.”

Because the batteries for EVs are mainly installed in the underfloor area, their casings have very high requirements in terms of hardness and crash safety. At the same time, the structures have to be as lightweight and compact as possible, which is where conventional materials, such as aluminum and carbon steels, reach their limits.

For example, the Tesla Model S battery pack weighs about 1,200 pounds (depending on capacity) – 25% of the total weight of the entire EV. A 20% reduction in battery pack weight would shed nearly 250 pounds from the vehicle’s curb weight.

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