Identifying key assumptions and differences in life cycle assessment studies of lithium-ion traction batteries with focus on greenhouse gas emissions

Abstract

The various studies that consider the life cycle environmental impacts of lithium-ion traction batteries report widely different results. This article evaluates the inventory data and results to identify the key assumptions and differences in the studies. To aid the identification, we compile the reported life cycle greenhouse gas emissions of batteries. The studies find production-related emissions in the range of 38-356 kg CO2-eq/kWh. One of the main sources of the large variations stems from differing assumptions regarding direct energy demand associated with cell manufacture and pack assembly. Further differences are due to assumptions regarding the amount of cell materials and other battery components. The indirect emissions associated with the use phase depend on the conversion losses in the battery, the energy required to transport the weight of the battery, and the carbon intensity of the electricity. Of the reviewed studies assessing the use phase, all estimate energy use associated with conversion losses while only one considers the mass-induced energy requirement. Although there are several industrial end-oflife treatment alternatives for lithium-ion batteries, very few studies consider this life cycle stage. Studies using the "recycled content" approach report emissions in the range of 3.6-27 kg CO2-eq/kWh battery, while studies using the "end-of-life" approach report emission reductions in the range of 16-32 kg CO2eq/kWh battery. The uncertainty associated with the end-of-life results is high as the data availability on industrial process is limited. Based on our findings, we discuss how the life emissions of lithium-ion traction batteries may be reduced.

Life cycle assessment of PV‐battery systems for a cloakroom and club building in Zurich

“…The electrode materials (eg, lithium nickel‐cobalt‐manganese oxide [NCM] cathode or lithium iron phosphate [FePO 4 ] cathode) have a lower influence on the greenhouse gas emissions of battery production . The greenhouse gas emissions of the storage system with current LiNCM batteries modelled in this study amount to 185 kgCO 2 ‐eq/kWh and are therefore about in the middle of the range of previous publications, which spans from 38 to 356 kgCO 2 ‐eq/kWh . Only one study was found that quantified the environmental impacts of a stationary battery storage system used in a hybrid power plant consisting of a wind park, a PV system, and several diesel generators .…”

“…38 The greenhouse gas emissions of the storage system with current LiNCM batteries modelled in this study amount to 185 kgCO 2 -eq/kWh and are therefore about in the middle of the range of previous publications, which spans from 38 to 356 kgCO 2 -eq/kWh. 38 Only one study was found that quantified the environmental impacts of a stationary battery storage system used in a hybrid power plant consisting of a wind park, a PV system, and several diesel generators. 39 The greenhouse gas emissions of the production of the analysed battery with a lithium nickel cobalt oxide cathode and a lithium titanate anode amount to approximately 290 kgCO 2 -eq/ kWh and are therefore significantly higher compared with the present study.…”

Integrating Batteries in the Future Swiss Electricity Supply System: A Consequential Environmental Assessment

“…Several changes were made to this original inventory to represent the consequential methodology and the intended perspective and to integrate newly available data (Ellingsen et al. ; Peters and Weil ).…”

“…The inventory of the battery direct life cycle was based on data collected at an earlier stage of this research project (Vandepaer et al 2017). Several changes were made to this original inventory to represent the consequential methodology and the intended perspective and to integrate newly available data (Ellingsen et al 2017;Peters and Weil 2017).…”

Energy use for GWh-scale lithium-ion battery production

“…Estimates of energy usage and greenhouse gas (GHG) emissions associated with producing lithium-ion (Li-ion) batteries have been shown to vary considerably (Ellingsen et al 2017, Peters et al 2017, Romare and Dahllöf 2017. Energy requirements related to the mining and processing of raw materials appear to be in reasonable agreement between studies (Dunn et al 2014), while energy used for module or pack assembly is considered to require only minimal amounts of energy (Dai et al 2019), leaving the cell manufacturing processes as the largest source for the variation.…”