The HELIOS European project, funded by the H2020 Programme, aims to develop lighter, modular hybrid Li-ion battery packs for EVs that combine same-size modules with high-power and high-energy cells to meet customer demands for fast charging and long-range capabilities. Nevertheless, it is important to consider the potential environmental impacts associated with the disposal of such hybrid batteries. This includes the consumption of a wider range of raw materials, the release of hazardous substances, and the emission of greenhouse gases. To address these concerns, the HELIOS project also focuses on improving the sustainability of the battery pack by creating designs for easy reuse in second-life applications and by developing recycling strategies at the End-of-Life (EoL) of the battery pack. The project has progressed in three key research areas: 1) Designing the battery pack to incorporate possible second-life scenarios using a modular configuration and enhanced dismantling techniques. 2) Froth flotation experiments were carried out to study whether graphite could be recovered in a reusable form and to create data for future LCA calculations. 3) Parallel to the froth flotation experiments, LCA methodology supported by the ISO 14040 series was used to create a baseline to evaluate the environmental impacts of the hydrometallurgical recycling of the NMC811-graphite cells. This baseline could be used later to assess the impact of graphite recovery by froth flotation, as the current LCA baseline excludes the recovery of anode materials (graphite and LTO).