Life Cycle Assessment of Lithium-ion Batteries for Electric Vehicles
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Increased awareness and concern about climate change has made the topic a priority the political agendas worldwide, and the necessity of international action has been recognized. Both national and international goals have been established in order to reduce the anthropogenic greenhouse gas (GHG) emissions. An expected increase in personal mobility, however, makes it difficult for the transport sector to achieve reductions in GHG emissions. In connection with the goal of reducing GHG emissions from the transport sector, the substitution of internal combustion engine vehicles by electric and hybrid electric vehicles has gained much attention due to their reduced tailpipe emissions. Although critics point to the additional environmental impacts associated with batteries, there is limited knowledge of the impacts associated with traction batteries. Thus far, only a small number of studies have been carried out to quantify these impacts. Unfortunately, there is high uncertainty associated with these previous studies, and the results and conclusions of these studies vary widely. With higher certainty than proceeding studies, our study will determine the environmental impacts associated with the production and use of lithium-ion traction batteries for electrical vehicles. This will be accomplished by the application of the method referred to as life cycle assessment (LCA). To this end, two battery inventories, representing different versions of the same battery model, are compiled. The data for these inventories are heavily based on industry data, but has also been supplemented with literature data. Due to the involvement and cooperation of these major industry players, these inventories have higher resolution and certainty than the former studies. Conducted in addition to the conventional LCA method, structural path analysis has allowed for the identification of the most emission-intensive processes and components, and their value chains. Our study shows that the newer battery offers lower environmental loads in all impact categories investigated. The manufacture of the battery cells, the positive electrode paste, and the negative current collector contribute the most to these environmental impacts. The production phase climate change potential impacts reported in our study are higher than those in previous studies. This is primarily due to high energy requirements for the production of the batteries. Our study shows that both the production phase and the use phase impacts of the batteries are greatly influenced by the electricity mix consumed. This makes Norway a well-suited location for both production and use of electrical vehicle batteries. In the light of the high climate change impacts reported in our study, the policies pertaining to electrical vehicles should be reassessed. At the same time, our findings show research and development in the battery industry can yield large environmental impact reductions. Our study has a comprehensive system, and the reported results have high certainty. The findings of our study provide much needed knowledge to the scientific literature on environmental impacts associated with traction batteries.