Pretreatment processing and recycling-oriented characterization of micromobility spent lithium-ion batteries (Université de Liège)

Abstract

The transportation sector is going through a big technological change and electronic mobile devices and vehicles are becoming increasingly important contributors to decrease the environmental impacts caused by the tailpipe emissions of internal combustion vehicles. Lithium-ion batteries (LIBs) are often used as electrochemical energy storage devices in powering electric transport systems. However, the increasing rate of production of LIBs is not followed by the rate of recycling. Moreover, the currently established processes are facing losses. The present study is based on the analysis of four battery modules of stand-up scooters. The investigations started by the pretreatment stage, where the e-scooters and battery modules were dismantled manually, followed by the depollution, conducted by discharging in a salt solution. As part of the processing stage, liberation included a single-stage size reduction using a cutting mill and separation using vibrational sieving with a set of custom sorting sieves. In addition, the liberation of the battery cells and pre-shredded material were tested using electric pulse fragmentation and attrition water washing. After shredding and sieving, on the generated mid and fine size fractions, microscopic investigations and chemical analysis were conducted. By chemical analysis, the segregation of the high-value materials to the fine size fractions was investigated. For microscopical investigations, optical and scanning electron microscopy (SEM) was employed, to analyze the relationship and liberation of the current collector foils and their active materials. Quantitative image analysis by segmentation and thresholding has been done using a collection of machine learning algorithms. The chemical analysis results were compared with the quantitative image analysis results. The development of lithium-ion batteries recycling has been industry-driven, unlike the development of new lithium-ion batteries, which are considering mainly the manufacturing cost and performance, without implementing strategies such as Design for Recycling (DfR). To develop efficient large-scale economical recycling facilities, battery researchers and manufacturers must focus more on improving the recyclability of lithium-ion batteries.