Advancements and Projections in Utility-Scale Lithium-Ion Battery Energy Storage System Components : Study of System Design and Future Technologies

Sammanfattning

As the global transition toward renewable energy accelerates, utility-scale Battery Energy Storage Systems (BESS) have emerged as key enablers for grid stability and green energy integration. This thesis investigates the technical and economic development of so called Balance of System (BoS) components within lithium-ion BESS, with a specific focus on future advancements over the next five years. Conducted in collaboration with Vattenfall AB, the study employs a comprehensive mixed-methods approach including simulation modeling, cost analysis, and a hybrid solar-BESS case study. Key aspects examined include power conversion systems, thermal management, control systems, electrical wiring and enclosure design. The emerging technologies liquid immersion cooling, distributed power conversion systems and larger lithium iron phosphate (LFP) cells are evaluated for their potential to enhance performance, reliability, and cost-efficiency. The results show that liquid immersion cooling significantly improves thermal performance and battery lifetime while reducing auxiliary energy consumption. Distributed PCS provide enhanced redundancy and grid integration, with more efficient operation. Larger LFP cells reduce BoS complexity and overall cost, although with trade-offs in availability, efficiency and heat generation. Comparative analyses highlight how design choices impact key metrics such as Levelized Cost Of Storage (LCOS), Round-Trip Efficiency (RTE), availability, and degradation rate. Results demonstrate significant synergies and trade-offs between technical performance and lifecycle costs, offering insights into how system design choices can optimize long-term viability. This research contributes to the understanding of how BESS components and configurations can evolve to support a more resilient, sustainable and economically competitive energy future.