Life cycle assessment of nickel-rich lithium-ion battery for electric vehicles A comparatative LCA between the cathode chemistries NMC 333 and NMC 622

Abstract

Nickel-rich lithium-ion cells are entering the market for electric vehicles, due to their higher density (kWh/kg) and less content of cobalt which has been appointed as a critical raw material. With higher density, longer driving distance per charge can be achieved since greater energy capacity is obtained per kg battery. However, the increase in energy density may be at the expense of the lifetime of batteries. There is ongoing research on the aging of new Ni-rich Li-ion cells for vehicle applications on how the different factors affect aging such as material composition, cell design, temperature, and internal pressure. This Master’s thesis has investigated the environmental impacts of Ni-rich Li-ion battery by conducting a Life Cycle Assessment to get an overall picture of the total environmental impact throughout its life cycle - from raw material extraction, through manufacturing processes and use, to waste management. The cathode chemistry of the Ni-rich Li-ion battery has chosen to be NMC622 which consists of the following active electrode material: 60% nickel, 20% Manganese and 20% Cobalt. The NMC622 battery is compared NMC333 which more common cathode chemistry for electric vehicles and the comparison has been done with respect to how much energy (kWh) that has been provided over the service life. According to the normalized and weighted LCIA results, NMC622 has around 2% higher environmental impact compared to NMC333. This is mainly due to that NMC622 has a higher contribution to the impact categories acidification and particulate matter from the production of nickel sulfate used in the cathode. The use phase was also considered as a hotspot in the life cycle where NMC622 has 2% lower plug-to-wheel consumption than NMC333 due to having around 8% higher energy density (kWh/kg). Other impact categories that accounted for the highest share of the total environmental impact was climate change and ionizing radiation which were also mainly due to the production of the cathode. Although the difference in environmental impact between batteries is too small to draw any conclusions given the uncertainties, the study provides insight into potential hotspots in the life cycle. Furthermore, the study points out which components and materials which might have the greatest influence on the difference in environmental impact between NMC622 and NMC333.