Researchers Develop Improved NMC Battery Pack for Electric Buses

Why It Matters

Higher energy density NMC cells can extend bus range while reducing weight, addressing key performance and cost pressures in the growing electric bus market. Achieving TRL 6 de‑ridges the path to commercial deployment, boosting Europe’s competitiveness in heavy‑duty electrification.

Key Takeaways

• EU funds SIERRA with €8 million for NMC bus batteries.
• Goal: TRL 6 lightweight pack validated for industrialisation.
• Multiscale modelling optimizes thermal, mechanical safety.
• One‑shot multi‑material housing reduces weight and production steps.
• Integrated cooling and printed busbars enable high‑power fast charging.

Pulse Analysis

The electric bus sector is at a crossroads between competing battery chemistries. While lithium‑iron‑phosphate (LFP) offers safety and cost advantages, nickel‑rich NMC cells deliver superior specific energy, a critical factor for extending range and reducing vehicle weight. As European cities push for higher utilization rates and faster turnaround, operators demand batteries that combine high energy density with robust thermal management and rapid charging capabilities.

SIERRA tackles these challenges through a suite of cutting‑edge technologies. Multiscale modelling allows engineers to simulate thermal and mechanical stresses across the pack, informing a compact design that maximises safety without excess mass. A one‑shot manufacturing process creates lightweight, multi‑material housings, cutting assembly steps and material waste. Integrated cooling channels and printed busbars support high‑power charging, while multi‑level monitoring provides real‑time state‑of‑charge, health, and structural data, simplifying the battery management system. The use of a digital twin links pack performance to vehicle dynamics, ensuring seamless integration and accelerated validation.

Reaching TRL 6 positions the SIERRA pack for near‑term industrialisation, offering European manufacturers a domestically developed, high‑performance alternative to imported solutions. This aligns with EU climate goals and the push for sustainable mobility, potentially lowering total cost of ownership for transit agencies. By proving that NMC technology can meet the rigorous demands of heavy‑duty transport, the project could reshape supply chains, stimulate local battery production, and accelerate the rollout of electric buses across Europe.