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Battery housing made of steel for the e-car

How steel protects battery cells

Safe and economical: steel battery housing saves the core of the electric car in the event of a crash

© photos: thyssenkrupp Steel

The battery is both the definitive element of an electric car and its most sensitive and costly component. Automobile manufacturers expect the energy storage system will make up between 30 and 50 percent of the total cost of an electric car. Automakers around the world are currently working on strategies for expanding production capacities and supply infrastructures along the entire value chain.

At the interface between the powertrain and the structural elements, the battery presents both manufacturers and material suppliers with a complicated task from a conceptual standpoint. The top priority is to provide maximum protection for the core components of electromobility, but the requirements have many layers. The battery has to be crash-proof and corrosion-resistant, electromagnetically shielded, and cooled.

Steel protects the battery in electric cars

Highly stable safety battery housing is a part of the selectrify® initiative in which thyssenkrupp Steel bundles its electromobility research and development activities. Affordable, lightweight vehicle structure solutions and electrical steel used to make electrical drive motors especially efficient make up further components of the initiative. All of these demonstrate the enormous potential of innovative steel solutions for vehicles with electric drives.

The battery is a recent addition to electric vehicles, and a key component at that. The rechargeable lithium-ion batteries available today have an extremely high level of performance, but they are also immensely sensitive. Any sort of damage runs the risk of devastating fires, which can put passengers and first responders in harm’s way following an accident.

Daniel Nierhoff

Safely housing the battery is the top priority.

Dr. Daniel Nierhoff, Project Engineer

That’s why comprehensive protection for the battery against crash impacts is protection for passengers first and foremost, and why automotive developers treat this issue with the upmost importance. “Safely housing the battery is the top priority when it comes to providing vehicle occupants with the best protection possible,” says Dr. Daniel Nierhoff from the selectrify® project team. On the one hand, the housing has to be capable of withstanding a side impact, a bump on the road, or a foreign object striking the battery housing from below without giving an inch. On the other hand, it has to be as light and compact as possible in order to make the most efficient use of the installation space and leave more room for even bigger batteries, which would offer longer vehicle ranges.

Batteries housed in steel: safe, lightweight, inexpensive

Batteries housed in steel offer several advantages. “The findings show that our new portfolio of ultra-high-strength dual-phase and manganese-boron steels are the ideal materials for our component,” says Nierhoff. A steel solution in the 70-kWh class can meet crash performance requirements while being nearly as light as a traditional battery housing made from aluminum and only costing half the price to build. “Simply put, we’re talking here about cost savings amounting to hundreds of euros without compromising on safety,” says Nierhoff. “That is a major difference in the area of car development, where costs are looked at in terms of cent amounts.”

In addition, steel also gains points in terms of fire protection and electromagnetic compatibility. Just like the reference structure, the battery concept is also scalable and can be flexibly adapted to the various different OEM platforms.

Batteries Housed in Steel

In brief – batteries housed in steel

Weight – weighs exactly the same as an aluminum reference model

Price – costs only around half as much

Crash safety – thanks to cutting-edge, high-strength materials

Design – high-tech materials leave more room for the battery

Other advantages of batteries housed in steel::

  • Better electromagnetic shielding against static/low-frequency fields
  • Fewer complex joining techniques
  • None of the delta-alpha problems of composite structures
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