Although millions of electric cars and plug-in hybrids are already on the roads worldwide, there are still no generally applicable standards for the individual components. However, significant efforts are currently being made to standardize individual vehicle assemblies and establish a cross-market component standard.
Increasing the range of the vehicles by improving the storage capacity of the batteries and efficient energy recovery is currently one of the main areas of focus. In addition, reducing the weight of the individual vehicle components can also help to reduce the amount of energy required to overcome driving resistance (e.g. tire rolling, gradient, acceleration).
To this end, Evonik, Forward Engineering, LION Smart, Lorenz Kunststofftechnik and Vestaro (a joint venture of Evonik and Forward Engineering), began working together on a modular-multi-material approach at the end of 2019. Today, the partnership has developed a brand-independent, cost-effective solution that significantly reduces the weight of the battery housing by approximately 10 percent compared to other commonly used material combinations, without any loss in mechanical properties.
Developed for three different battery-sizes, 65kWh, 85 kWh and 120 kWh for use in various vehicles sizes and class, one of the key elements of the new battery concept is the glass fiber (GF)- Sheet Molding Compound (SMC) cover. Based on the high-performance epoxy curing agent VESTALITE® S from Evonik, the new SMC delivers the performance levels of the previous metal-based battery enclosures, while being significantly lighter than the current more cost-prohibitive SMC Materials.
“Battery modules and their housing has become a key area for improving the performance, efficiency and affordability of modern electric vehicles,” said Dr. Leif Ickert, Marketing Manager Composites and Adhesives, Evonik Operations GmbH & Managing Director, Vestaro GmbH. “Composite technologies provide strength and versatility, so offer a very promising solution for future battery system concepts. Our new glass fiber-reinforced SMC delivers the performance and economic benefits the automotive industry requires to push ahead with the next generation of sustainable e-mobility concepts.”
The glass-fiber-reinforced epoxy SMC has excellent mechanical properties including flexural and impact strength, and by using epoxy resin instead of the usual polyester resin, other problems often encountered during downstream processing of glass-fiber-reinforced SMC materials have been eliminated. Additionally, it meets all specifications regarding fire resistance and is easy to process even when complex geometries are demanded. The entire concept was successfully tested for suitability for series production and safety even under extreme conditions.
Additionally, consortium partner, Lorenz Kunststofftechnik has developed an established process for successfully recycling glass fiber-reinforced SMC materials – an important argument in view of the increasing sustainability requirements in the automotive industry.