SIERRA

The transport sector – especially heavy commercial vehicles such as buses and trucks – faces the urgent task of significantly reducing greenhouse gas emissions in order to achieve European climate targets. Electric drive systems are a key lever in this effort.

Battery systems that combine high energy density, maximum safety, long service life, fast charging capability, and low weight are needed for use in heavy-duty applications. Nickel-rich NMC cells offer great potential for increasing specific energy. At the same time, higher energy density increases the demands on thermal management, structural integrity, and continuous condition monitoring. Conventional battery pack architectures are increasingly reaching their limits in terms of safety, durability, and system weight.

SIERRA: Holistic development to application readiness

The European research project SIERRA addresses these challenges with the development of a safe, sustainable, lightweight, and powerful battery pack based on nickel-rich NMC cells. The focus is on applications in electric bus transport. The overall system will be validated to technology readiness level 6 (TRL6) and thus prepared for subsequent industrialization.

Technological innovations include:

• Multiscale modeling for compact and safe battery pack design and simulation of thermal and mechanical behavior
• Resource-saving one-shot manufacturing of lightweight multi-material housings
• Multi-stage monitoring concepts (structural monitoring, thermal mapping, determination of state of charge and state of health) while reducing the system complexity of battery management
• Fully integrated cooling systems and printed busbars to support high charging capacities across a wide operating window

The integration of the battery pack into the overall vehicle is simulated using a digital twin. All development work follows the “safe and sustainable by design” approach and takes safety and sustainability aspects into account from the outset.

Contribution of AIT: Model-based optimization at the pack and vehicle level

The AIT Austrian Institute of Technology contributes its comprehensive expertise in the model-based development of battery systems to the European consortium. The focus is on simulations at the battery pack and overall vehicle level in order to systematically develop and validate safe and energy-efficient lightweight construction concepts.

Through virtual analysis of thermal behavior, energy flows, and safety-relevant parameters, AIT supports optimization in terms of weight, performance, and operational safety. Simulations make it possible to validate design decisions at an early stage, reduce development risks, and increase system performance in a targeted manner.

Dr. Mirza Popovac, project manager at AIT, emphasizes: “In the SIERRA project, we use simulation-based methods at the battery pack and vehicle level to develop safe and energy-efficient lightweight battery concepts for heavy-duty transport. This allows us to validate design decisions at an early stage and specifically improve the performance of future electric commercial vehicles.”

Consortium

SIERRA brings together eleven partners from seven European countries and covers key competencies along the battery value chain – from material development and system integration to validation.