Battery system integration for electric mobility

Advances in lithium-ion battery technology have underpinned the rapid growth of electric vehicles, but further cell-level improvements are increasingly marginal. In contrast, system-level battery integration, shifting from modular assemblies to embedded, load-bearing architectures, offers transformational gains. Compared with conventional cell-to-module designs, recent architectures achieve a volumetric efficiency of 60%–72%, together with 10% lower system cost, and the elimination of hundreds of structural components in traction packs, reflecting the unification of structural and electrochemical functions across cell-to-pack, cell-to-chassis, and emerging cell-to-vehicle systems. However, deeper integration weakens established safeguards such as thermal isolation and diagnostic accessibility, while it constrains disassembly, reparability, and material recovery. In parallel, sustainability and policy objectives increasingly require life cycle modeling and techno-economic forecasting to be integrated into system design. These trade-offs and co-optimization pathways shape the safety, scalability, and sustainability of battery system integration and are synthesized here within an M4 framework linking mechanism, modularity, management, and mission at the system level.