Environmental Benefit Assessment of Second-Life Use of Electric Vehicle Lithium-Ion Batteries in Multiple Scenarios Considering Performance Degradation and Economic Value.

Second-life use of electric vehicle lithium-ion batteries (LIBs) is an inevitable trend; however, battery performance degradation increases environmental loads. This study evaluated the life cycle environmental impacts of second-life use of LIBs in multiple scenarios, considering performance degradation and economic value. The results showed that a component replacement rate of retired LIBs below 50% made the batteries worthy of repurposing. Reusing whole packs of retired LIBs was better than using only cells or modules owing to the environmental loads from diagnosis, disassembly, replacement, and test processes. The battery energy density and performance degradation significantly affect the maximum return on the environmental input. Compared with lithium iron phosphate (LFP) batteries, new lithium nickel manganese cobalt oxide (NMC) batteries, or lead-acid batteries, using retired NMC-811 batteries with capacities as low as 60.7% for energy storage systems to store wind electricity rather than hybrid or photovoltaic electricity, had substantial environmental benefits, including a low global warming potential. Considering the costs of battery recycling, labor, and electricity, using whole packs of retired LIBs could simultaneously achieve high economic and environmental values in energy storage and peak shaving scenarios.