Life Cycle Environmental Assessment of Lithium-Ion and Nickel Metal Hydride Batteries for Plug-In Hybrid and Battery Electric Vehicles

TLDR

The study provides a life‑cycle assessment of NiMH, NCM, and LFP batteries for plug‑in hybrid and battery electric vehicles, offering a publicly available inventory adaptable to any powertrain. The authors compiled a component‑wise life‑cycle inventory for these batteries, evaluated them with an energy‑storage functional unit and midpoint impact indicators, and performed detailed contribution analyses to pinpoint emission‑driving processes. The analysis shows NiMH batteries have the highest environmental impact per unit of storage, followed by NCM and LFP, and reports global warming emissions higher than prior estimates.

Abstract

This study presents the life cycle assessment (LCA) of three batteries for plug-in hybrid and full performance battery electric vehicles. A transparent life cycle inventory (LCI) was compiled in a component-wise manner for nickel metal hydride (NiMH), nickel cobalt manganese lithium-ion (NCM), and iron phosphate lithium-ion (LFP) batteries. The battery systems were investigated with a functional unit based on energy storage, and environmental impacts were analyzed using midpoint indicators. On a per-storage basis, the NiMH technology was found to have the highest environmental impact, followed by NCM and then LFP, for all categories considered except ozone depletion potential. We found higher life cycle global warming emissions than have been previously reported. Detailed contribution and structural path analyses allowed for the identification of the different processes and value-chains most directly responsible for these emissions. This article contributes a public and detailed inventory, which can be easily be adapted to any powertrain, along with readily usable environmental performance assessments.