Comparative life cycle assessment of Li-Sulphur and Li-ion batteries for electric vehicles

Abstract

Nowadays, most of the electric vehicles (EVs) are powered by Lithium-ion (Li-ion) batteries due to their high energy density, higher power density and degree of development relative to other battery technologies. As Li-ion technology evolves and the EVs fleet increases, it is important to understand the environmental impacts of mass-producing the battery packs for EVs. However, with 80-150 Wh/kg energy density, current Li-ion batteries are not able to power the EVs for a comparable driving range with conventional vehicles. Lithium-sulphur (Li-S) batteries have emerged as promising battery technology, with a higher theoretical capacity and energy density than Li-ion batteries used today. Moreover, Li-S batteries presumably present a lower environmental profile due to their chemical composition compared to Li-ion ones. To verify this statement, this study performs a life cycle assessment (LCA) of Li-S battery cells (under industrial development at the moment) that have been scaled up accordingly to estimate their performance as a battery for EVs. This comparison will provide the impact of each battery and the potential benefits in terms of environmental impact indicator values of the Li-S technology. The impacts of the Li-S battery are compared with those of a Nickel-Cobalt-Manganese (NCM) battery under the same driving distance. The environmental impact assessment results show that Li-S batteries present a most favourable environmental profile compared to NCM batteries, especially in the natural resource depletion categories where the Li-S battery has 70%-90% lower values compared to the Li-ion one.