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Toward Material Efficient Vehicles: Ecodesign Recommendations Based on Metal Sustainability Assessments

Abstract:

Current End-of-Life Vehicle (ELV) recycling processes are mainly based on mechanical separation techniques. These methods are designed to recycle those metals with the highest contribution in the vehicle weight such as steel, aluminum, and copper. However, a conventional vehicle uses around 50 different types of metals, some of them considered critical by the European Commission. The lack of specific recycling processes makes that these metals become downcycled in steel or aluminum or, in the worst case, end in landfills. With the aim to define several ecodesign recommendations from a raw material point of view, it is proposed to apply a thermodynamic methodology based on exergy analysis. This methodology uses an indicator called thermodynamic rarity to assess metal sustainability. It takes into account the quality of mineral commodities used in a vehicle as a function of their relative abundance in Nature and the energy intensity required to extract and process them. This method is proposed as a tool to identify the most critical components in a vehicle so as to define specific ecodesign recommendations for them. The methodology is applied to a SEAT Leon 2.0 Diesel III model (segment C). Main recommendations are focused on reducing the use of metals with high thermodynamic rarity values such as Ag, Au, Cu, Ga, In, Pd, Pt, Sn, Ta, and Te. These metals are mainly used in electrical and electronic equipment. It is also recommended to reduce the disassembly time of a number of critical components such as airbag unit, electronic control unit, lighting switcher, antenna amplifiers, panel instrument, sensors, infotainment unit, light-emitting diodes (LEDs), and motors. A fast and easy disassembly would allow in subsequent phases to apply specific recycling processes based on mechanical and hydrometallurgical hybrid approaches instead of only mechanical separation techniques.