Composites Today

Magazine For Composites Professionals

New generation of electric vehicle battery packs

Evonik as part of the VESTARO GmbH consortium of companies working to produce lighter and more cost-effective solutions for battery electric vehicles (BEV), has developed a new generation of battery packs, the “Pure Performance Battery” (PPB). Based on Sheet Molding Compound (SMC) technology made using Evonik’s curing agents, 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 new 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 percent compared to equal performing covers made from more cost-prohibitive materials, the state-of-the-art SMC materials also deliver the performance levels of previous metal-based enclosures but enable the design-freedom for semi-integral integration.

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 additions of Minth’s in-depth know-how for aluminum solutions, the enhanced consortium tackled two major challenges for today’s battery packs: the bottom impact use case and the vehicle integration.

To meet these 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 GmbH, which increases the 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 instead.

Additionally, due to the improved bottom impact performance of the sandwich floor, the space required for the module mounting could be reduced. The creation of these extra spaces for battery cells has led to an overall capacity increase of 10kWh, from 65 to 75 kWh, with nearly the same outer dimensions of the battery pack compared to the Group’s previous generation.

Designed and validated using Forward Engineering’s unique BEV-floor structure development tool, the new “Pure Performance Battery” is around 2.1 meters long and 1.58 meters wide with maximum heights between 0.15 – 0.22 meters (Penthouse-architecture) and is suitable for a variety of vehicle architectures. In terms of weight, the new GF-SMC cover-based PPB competes with today’s high-end solutions but delivers a significant increase in performance.

Additionally, the battery’s semi-integral modular series 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. The supercell concept is based on LION Smart’s LIGHT Battery which enables a calculated fast charging result of around 13 minutes with charging power constantly above 200 kW (10 % – 80 % SOC). The system is currently being developed with the aim of achieving charging times of less than 10 minutes.

Improving the sustainability of vehicle components is also an important topic for the automotive industry, so the new cover has been designed to be easily demounted to provide quick access to battery-modules and peripheral equipment. Additionally, the cover itself can be recycled via LORENZ Kunststofftechnik’s unique recycling process and used again for new composite parts.

Leave a Reply