Battery housing design is critical to the safety and range of electric vehicles, yet current mainstream approaches struggle to balance weight, cost, and safety. Magna's OptiForm one-piece battery housing technology aims to break through these trade-offs with a system-level solution, according to a report by Chinese outlet Dian Dong Bang.
Traditional battery housings fall into two main routes: aluminum extrusion profiles and high-strength steel roll-forming. Aluminum extrusions offer flexible cross-sections, light weight, and corrosion resistance, but come with higher material costs. High-strength steel roll-forming is mature, strong, and cost-effective, but heavier, which hurts battery pack weight reduction.
Both routes share a common bottleneck: too many parts. Multi-beam frames require numerous welds at each joint, and every weld is a potential risk point. Welding heat can cause deformation, affecting sealing surface dimensions. Battery pack sealing relies entirely on weld quality, so a single defective weld can lead to leakage.
To reduce welds at the source, more automakers are turning to stamping, using a single steel sheet to form the tray directly. Fewer welds mean fewer leak paths and lower deformation risk. However, stamping has its limits: drawing a deep, large housing from flat steel is challenging, requiring large draft angles and corner radii that eat into internal space for cells. For EVs, space is range.
OptiForm's system-level approach
OptiForm is not a material or a single process but a complete system capability, integrating material selection, structural design, forming processes, and simulation optimization. The one-piece forming process is its foundation. It significantly reduces welds, improves sealing, and allows deeper drawing to accommodate larger cell capacities.
Compared to traditional stamping, OptiForm achieves a draft angle as low as 1.5 degrees, a bottom corner radius of 4 mm, and a projected corner radius of 75 mm. Housing thickness ranges from 0.9 to 1.8 mm. The projected dimensions reach 2.8 meters by 1.5 meters, with a drawing depth of 160 mm, covering mainstream BEV (battery-electric) packs. This design can free up space for up to about 10% more battery capacity, although the final gain depends on the vehicle platform and battery system design.
Magna also highlights cost benefits through reduced parts, processes, and assembly steps, leveraging mature stamping technology to ease mass production. However, the company notes that OptiForm requires investment in tooling and upfront development, with cost advantages more visible at the system level than per-part price, making it best suited for projects with scale or shared platform envelopes.
Two application scenarios
Magna envisions two typical applications. In non-conventional crash structures, where the body absorbs all collision energy, the battery pack does not need to bear crash loads. The OptiForm pack then consists of a one-piece upper cover, high-strength steel crossbeams, a water-cooling plate, and the battery tray, simplified by removing redundant crash structures. This reduces sealing surfaces and improves space utilization.
In conventional crash structures, where the pack still bears some crash load—the most common architecture—the housing uses hot-formed reinforced crossbeams, a cooling plate, adhesive layers, internal and external reinforcements, and the one-piece OptiForm tray. This approach is easier to integrate into existing platforms without major redesign. Material choices are flexible, with hot-formed high-strength steel or mild steel as needed. Side-impact performance can be met with stamped patches, and the bottom protection may eliminate the need for a separate underbody shield.
According to Magna engineers, OptiForm can be produced using existing stamping equipment without line upgrades, with challenges concentrated in upfront process analysis, tooling development, and commissioning. Magna's experience in forming complex body structures for premium vehicles—including small-radius forming and anti-wrinkle control—helps customers implement the solution efficiently.
OptiForm is not tied to a single material; it balances formability, strength, weight, corrosion resistance, joining methods, and cost based on customer goals. The technology offers a new option that balances cost, manufacturing efficiency, and reliability, and it is likely to complement rather than replace existing battery packaging routes, depending on vehicle positioning and weight targets.
