Life Cycle Assessment of a novel functionally integrated e-axle compared with powertrains for electric and conventional passenger cars

Road transport significantly contributes to climate change and air pollution. Efforts to reduce transport sector emissions include deploying battery electric vehicles and designing their powertrains for improved performance. The European H2020 funded Functionally Integrated E-axle Ready for Mass Market Third GENeration Electric Vehicles (FITGEN) developed a novel functionally integrated e-axle (the FITGEN e-axle) for electric vehicles. This paper presents the environmental performance of the FITGEN e-axle. Using the Life Cycle Assessment (LCA) methodology, the study compares the FITGEN e-axle to the 2018 State-of-the-Art (SotA) e-drive, besides diesel and petrol-fuelled powertrains. The FITGEN powertrain reduces climate impacts by 10 % and energy consumption by 17 %, compared with the 2018 SotA e-drive due to the efficiency improvements and components integration. It also outperforms the 2018 SotA e-drive in several other impact categories, such as human toxicity (4-10 %), land use (19 %), and mineral depletion (8 %). However, the FITGEN powertrain only outperforms diesel and petrol powertrains in climate change and fossil resource scarcity impact categories. These findings imply that more efforts are required to improve the environmental profile of electric powertrains. Metal mining and production, especially for copper and aluminium, are critical for toxicity impacts. The sensitivity analysis demonstrates the robustness of the results, with no significant shift in their ranking order. The following aspects should be considered to improve the performance of electric powertrains from a life cycle perspective: improvement of components efficiency, reduced use of electronics and component integration, and use of low-carbon energy mix from their metal mining sites to production and use.

Life cycle assessment of battery electric vehicles: Implications of future electricity mix and different battery end-of-life management

The environmental performance of battery electric vehicles (BEVs) is influenced by their battery size and charging electricity source. Therefore, assessing their environmental performance should consider changes in the electricity sector and refurbishment of their batteries. This study conducts a scenario-based Life Cycle Assessment (LCA) of three different scenarios combining four key parameters: future changes in the charging electricity mix, battery efficiency fade, battery refurbishment, and recycling for their collective importance on the life-cycle environmental performance of a BEV. The system boundary covers all the life-cycle stages of the BEV and includes battery refurbishment, except for its second use stage. The refurbished battery was modelled considering refurbished components and a 50% cell conversation rate for the second life of 5 years. The results found a 9.4% reduction in climate impacts when future changes (i.e., increase in the share of renewable energy) in the charging electricity are considered. Recycling reduced the BEV climate impacts by approximately 8.3%, and a reduction smaller than 1% was observed for battery refurbishment. However, the battery efficiency fade increases the BEV energy consumption, which results in a 7.4 to 8.1% rise in use-stage climate impacts. Therefore, it is vital to include battery efficiency fade and changes to the electricity sector when estimating the use-stage impacts of BEVs; without this, LCA results could be unreliable. The sensitivity analysis showed the possibility of a higher reduction in the BEV climate impacts for longer second lifespans (>5 years) and higher cell conversation rates (>50%). BEV and battery production are the most critical stages for all the other impact categories assessed, specifically contributing more than 90% to mineral resource scarcity. However, recycling and battery refurbishment can reduce the burden of the different impact categories considered. Therefore, manufacturers should design BEV battery packs while considering recycling and refurbishment.