Impact of Recycling on Cradle-to-Gate Energy Consumption and Greenhouse Gas Emissions of Automotive Lithium-Ion Batteries

Abstract

This paper addresses the environmental burdens (energy consumption and air emissions, including greenhouse gases, GHGs) of the material production, assembly, and recycling of automotive lithium-ion batteries in hybrid electric, plug-in hybrid electric, and battery electric vehicles (BEV) that use LiMn(2)O(4) cathode material. In this analysis, we calculated the energy consumed and air emissions generated when recovering LiMn(2)O(4), aluminum, and copper in three recycling processes (hydrometallurgical, intermediate physical, and direct physical recycling) and examined the effect(s) of closed-loop recycling on environmental impacts of battery production. We aimed to develop a U.S.-specific analysis of lithium-ion battery production and in particular sought to resolve literature discrepancies concerning energy consumed during battery assembly. Our analysis takes a process-level (versus a top-down) approach. For a battery used in a BEV, we estimated cradle-to-gate energy and GHG emissions of 75 MJ/kg battery and 5.1 kg CO(2)e/kg battery, respectively. Battery assembly consumes only 6% of this total energy. These results are significantly less than reported in studies that take a top-down approach. We further estimate that direct physical recycling of LiMn(2)O(4), aluminum, and copper in a closed-loop scenario can reduce energy consumption during material production by up to 48%.

Environmental impacts of hybrid, plug-in hybrid, and battery electric vehicles—what can we learn from life cycle assessment?

“…High collection rates and that almost all material is recovered to virgin quality have been assumed (Van den Bossche et al 2006). The potential for such recycling of lithium-ion batteries, which is both energy efficient and has high recovery rate, has been investigated in several papers (Dunn et al 2012;Gaines et al 2011;Li et al 2013;Sullivan et al 2011). However, only in the case of lead acid batteries are highly efficient recycling processes currently in practice.…”

“…Battery manufacturing, based on a study by Majeau-Bettez et al (2011), is pointed out as an important explanation. Actually, Dunn et al (2012) have investigated the difference between the values reported by Majeau-Bettez et al (2011) and Notter et al (2010a), and observed that the energy used to manufacture specific battery subcomponents is more than 1 order of magnitude larger in the study by Majeau-Bettez et al In trying to explain the cause, Dunn et al (2012) found that studies which use a more detailed "process level" approach to the life cycle inventory, as Notter el al., produce much lower values ). An average vehicle lifetime of 230,500 km corresponding to 13.7 years has been used, based on statistical data from the Belgian vehicle registration database.…”

“…In the case of lithium-ion batteries, it is the production of battery cells which is most energy demanding (Volkswagen Group 2012), and more specifically the processing of the active materials (Dunn et al 2012). While each chemistry has a number of viable synthesis procedures, there are a number of very energy-intensive processes, such as grinding cathode materials down to very fine particles (Kushnir and Sandén 2011) that are sometimes needed depending on the desired properties of the final material.…”

Plug-in vs. wireless charging: Life cycle energy and greenhouse gas emissions for an electric bus system

“…The SOCR for the wirelessly charged battery is the same as that of the plug-in charged battery (60%). The battery weight (kg) can be calculated by dividing the battery capacity (kW h) by the battery specific energy (0.13 kW h per kg of Li-ion battery) [29]. Therefore, the percentage of vehicle mass reduction due to primary downsizing can be determined, relative to a bus of 15 t, comprising the assumed curb weight of 14 t [4] and the constant average weight of 1 t for driver, passengers and cargo [30].…”

“…LMO was chosen because of its well established life cycle inventory, lower cost and abundance of manganese in nature [35,36]. The cradle-to-gate energy and GHG emissions are modeled as 75 MJ/kg battery and 5.1 kg CO 2 -eq/kg battery, according to a process LCA study of LMO batteries for electric vehicles that is specific to the United States [29]. When the OSM is 5%, RSC is 15% and NOR is 20%, the SOCR is 60% with the state of charge (SOC, %) assumed to swing around 35-95% for both plug-in and wirelessly charged batteries [28].…”