Toward Material Circularity and Manufacturing Sustainability in the Automotive Industry

Abstract

This paper reviews technologies being developed toward material circularity and manufacturing sustainability in the automotive industry; aluminum sustainability is used herein as an exemplar. While aluminum is increasingly used for lightweighting applications in the transportation industries to reduce energy consumption and carbon footprint, primary production of aluminum is energy-intensive with significant CO₂ emissions. However, remelting aluminum scrap only uses ~5% of the energy, resulting in significantly reduced emissions required to produce primary aluminum from bauxite ore. The wide use of recycled aluminum for transportation applications will ensure the sustainability of the supply chain. Another example is the use of renewable wood materials such as the recently developed “super wood” which is a densified natural wood with similar mechanical properties to metallic materials. For manufacturing processes, the development and evolution of energy-efficient large thin-wall die casting (also called mega/giga casting) will enhance the sustainability of automotive manufacturing. Alternative energy vehicles tend to have more simplified body structures, enabling the use of large and consolidated castings which significantly reduce welding, joining, and assembly operations. Reclaiming some of the high-value battery materials from electric vehicles is challenging. A patented “Hydro-to-Cathode” direct precursor synthesis process can leach out impurities, keeping the valuable metals in solution and eliminating multiple steps in the recycling flow. Additional technology advances are required to reclaim other materials. Ultimately, the combination of recycled/renewable materials and energy-efficient manufacturing processes will drive the automotive industry toward circularity and sustainability.