Reducing the climate change impacts of lithium-ion batteries by their cautious management through integration of stress factors and life cycle assessment

The use of Li-ion batteries for stationary energy storage in households represents a viable solution to mitigate climate change when compared with the reference situation of electricity supply from the grid in various countries. This study quantifies the climate change impacts of production, use, and disposal of NMC batteries and compares the impacts with provision of electricity from grids of six European countries to calculate their carbon handprints, a measure of positive climate impacts. The study also develops a general cycle life model for NMC batteries to show the impact of various stress factors on the lifetime of the battery, which was then used to show the impact of battery management on its climate change impacts due to varying energy throughput. Of the countries studied, the carbon handprint was the highest in Bulgaria at 13,450 kg CO2-eq. per energy throughput of the battery during its life cycle of 25.3 MWh. The lowest handprint achieved was in Finland at 2000 kg CO2-eq., while no handprint was achieved in Norway. Uncertainty in the data on Li-ion battery production and recycling was found to be of minor importance when the entire life cycle of the batteries was studied and compared with the baseline scenario. Operating temperature, cycle depth and average state of charge during cycling have significant impact on the lifetime of Li-ion batteries and hence on their carbon handprint. The longest lifetime with NMC batteries can be achieved by cycling the battery at low cycle depth at an average state of charge of around 50% and an operating temperature close to 25 degrees C. Operating the battery at 50% cycle depth instead of 90% cycle depth more than doubled the carbon handprint in all the counties studied except Norway.