Life cycle assessment of the energy consumption and GHG emissions of state-of-the-art automotive battery cell production

Abstract

As the production of automotive battery cells has expanded worldwide, concerns have arisen regarding the corresponding energy consumption and greenhouse gas (GHG) emissions. However, data on the energy consumption and GHG emissions of battery cell production are scarce, uncertain in quality and accuracy, and mostly outdated. To improve the availability and accuracy of battery production data, one goal of this study was to determine the energy consumption of state-of-the-art battery cell production and calculate the related GHG emissions. Machine specifications for energy consumption were gathered from multiple manufacturers during the planning and construction of a research factory in Germany with a theoretical output of 7 GWh per year of electrode capacity. The energy consumption and associated GHG emissions were determined for each step in the production process and for the process overall. It was found that only a few steps were responsible for most of the required energy and GHG emissions, with coating and drying, formation, and drying rooms consuming a combined 76% of the total energy and emitting 74% of all GHGs. A second goal was to determine the impact of internal energy sourcing on GHG emissions. It turns out that switching from a mix of electricity and natural gas to electricity only could reduce GHG emissions if the electricity used at the plant had a low GHG emission factor. In Europe, the Swedish electricity grid has the lowest GHG emission factor; the overall emissions of battery cell production could be reduced from 4.54 to 0.53 kg CO2-eq/kWh battery cell capacity if production was only powered by electricity. However, nuclear energy accounts for a large share (30%) of the electricity mix in Sweden, and is questionable from an environmental perspective.