Quantifying the life-cycle health impacts of a cobalt-containing lithium-ion battery

Abstract

Purpose: Lithium-ion batteries (LIBs) have been criticized for contributing to negative social impacts along their life cycles, especially child labor and harsh working conditions during cobalt extraction. This study focuses on human health impacts — arguably the most fundamental of all social impacts. The aim is to quantify the potential life-cycle health impacts of an LIB cell of the type nickel-manganese-cobalt (NMC 811) in terms of disability-adjusted life years (DALY), as well as to identify hotspots and ways to reduce the health impacts. Methods: A cradle-to-gate attributional life-cycle assessment study is conducted with the functional unit of one LIB cell and human health as the sole endpoint considered. The studied LIB is produced in a large-scale “gigafactory” in Sweden, the cobalt sulfate for the cathode is produced in China, and the cobalt raw material is sourced from the Democratic Republic of the Congo (DRC). Potential health impacts from both emissions and occupational accidents are quantified in terms of DALY, making this an impact pathway (or type II) study with regard to social impact assessment. Two scenarios for fatality rates in the artisanal cobalt mining in the DRC are considered: a high scenario at 2000 fatalities/year and a low scenario at 65 fatalities/year. Results: Applying the high fatality rate, occupational accidents in the artisanal cobalt mining in the DRC contribute notably to the total life-cycle health impacts of the LIB cell (13%). However, emissions from production of nickel sulfate (used in the cathode) and of copper foil (the anode current collector) contribute even more (30% and 20%, respectively). These contributions are sensitive to the selected time horizon of the life-cycle assessment, with longer or shorter time horizons leading to considerably increased or decreased health impacts, respectively. Conclusions: In order to reduce the health impacts of the studied LIB, it is recommended to (i) investigate the feasibility of replacing the copper foil with another material able to provide anode current collector functionality, (ii) reduce emissions from metal extraction (particularly nickel and copper), (iii) increase the recycled content of metals supplied to the LIB manufacturing, and (iv) improve the occupational standards in artisanal mining in the DRC, in particular by reducing fatal accidents.