Abstract
The continuous rise in global surface temperature has motivated industries and nations to take measures for carbon neutrality and net zero greenhouse gas emissions. A big chunk of these emissions comes from burning fossil fuels in the pursuit of energy and mobility. Transformation of transportation from fossil-based Internal Combustion Engine Vehicles (ICEVs) to Electric Vehicles (EVs) is crucial to achieving carbon neutrality. However, EV production, especially battery manufacturing, is environmentally intensive compared to ICEV production. Besides end-of-life cells, a considerable proportion of secondary supply from the Quality Control (QC) reject cells is also expected, as the giga-cell production setups commence operation. Therefore, understanding the environmental performance of battery recycling technologies is essential, reducing, simultaneously need for new materials and the environmental impact of virgin resource mining.
This study has combined the conventional production and recycling processes and performed a Life Cycle Impact Assessment (LCIA) of producing 1kg of NMC111 lithium-ion cell under varying proportions of virgin and recycled content. The production and recycling models are combined by using a mass allocation-based output from the recycling model by attributing the input requirements of every recycling process step with respect to the amount of recovered cathode active materials. Thoroughly using the data points from the relevant studies, Life Cycle Inventory (LCI) is compiled, and the combined model is tested individually for direct, hydrometallurgy, and pyrometallurgy recycling technologies
The results demonstrated that the impact followed the condition d{direct}<d{hydro}<d{pyro}<d{virgin}. Among all recycling technologies, pyrometallurgy appeared to be the most impact intensive due to high resource and energy consumption and low recovery rates of the constituents of positive electrode paste. Another interesting finding is that the impact is correlated highly with the carbon intensity of the electricity mix indicating recycling while being worthwhile, yet not the sole solution towards carbon neutrality. Also, to realize the benefits of recycling, industrial as well as government policies are instrumental.
Keywords
NMC111, positive electrode paste, direct recycling, hydrometallurgy, pyrometallurgy, allocation
