The Vestaro consortium of companies, working to produce lighter and more cost-effective solutions for battery electric vehicles (BEVs), has developed a new generation of battery packs, the Pure Performance Battery. Based on sheet molding compound (SMC) technology made using curing agents from Evonik, the new holistic battery system concept provides the automotive industry with a safe, lightweight, and, most importantly, cost-effective alternative to the traditional heavier metal-based solutions.
Formed at the end of 2019 to investigate alternative battery solutions, Vestaro first developed a cost-effective glass-fiber (GF) SMC cover based on Evonik’s high-performance epoxy curing agent, Vestalite S. In addition to reducing the weight of the battery housing by almost 10% compared with covers made from more cost-prohibitive materials, the state-of-the-art SMC material also delivers the performance levels of metal-based enclosures while enabling design freedom.
Following the publication of the successful results of Vestaro’s new GF-SMC cover produced by Vestaro partner Lorenz Kunststofftechnik, at the beginning of 2021, the consortium was boosted further when Tier 1 automotive component manufacturer Minth GmbH joined. With the addition of Minth’s in-depth know-how of aluminum solutions, the consortium tackled two major challenges for today’s battery packs — bottom impact and vehicle integration.
To meet stringent OEM requirements in terms of side pole and bottom impact without any leakage or failure, the consortium came up with a novel approach that fully utilized the design freedom of the versatile SMC material. The old bottom structure was replaced with an aluminum sandwich plate developed by Minth, which increases performance in terms of the bottom impact, but also plays a key role in the semi-integral vehicle concept. With this concept, the consortium was able to remove the additional side deformation elements and use the freed space for more battery cells.
Additionally, the improved bottom impact performance of the sandwich floor enabled a reduction in the space required for the module mounting. The creation of these extra spaces for battery cells has led to an overall capacity increase from 65 to 75 kWh, while maintaining nearly the same outer dimensions of the battery pack.
“Our new battery pack is designed for performance and it’s the exceptional properties of our Vestalite curing agents that give the unique epoxy-SMC cover its outstanding performance and safety potential in terms of fire-resistance and crash behavior,” said Sebastian de Nardo, Marketing Director for Adhesives and Composites at Evonik. “We’ve successfully overcome all concerns regarding the EMI-shielding performance of the GF-composites using Evonik’s broad material toolbox and expertise, and we can tailor the battery’s performance to meet each customer’s individual requirements.”
Designed and validated using Forward Engineering’s unique BEV-floor structure development tool, the Pure Performance Battery is around 2.1 meters long and 1.58 meters wide with maximum heights of 0.15 to 0.22 meters. It is suitable for a variety of vehicle architectures. In terms of weight, the new GF-SMC cover battery competes with today’s high-end solutions but delivers a significant increase in performance.
Additionally, the battery’s semi-integral modular design enables flexible adjustment of the number of modules, and the production of complex geometries in a one-step process enables tailored battery performance levels to suit all regional requirements.
Improving the sustainability of vehicle components is also an important topic for the automotive industry, so the new cover has been designed for easy removal to provide quick access to battery modules and peripheral equipment. Additionally, the cover itself can be recycled via Lorenz Kunststofftechnik’s recycling process and used again for new composite parts.