Influence of different discharge levels on the mechanical recycling efficiency of lithium-ion batteries.

Prior to the mechanical processing, discharging is necessary to prevent hazards. While the discharging process, different phenomena can occur changing the characteristics of the functional units of LIB. This study reveals the influence on the mechanical recycling and the obtained material when different discharge levels are used for various cells differing in their cell chemistry. It shows that for different cells, for example, copper deposits happen on the cathode as well as active material deposits on the separator foil. These new properties deteriorate the black mass quality and show contamination of the products with other material streams. It is being tested whether established sub-processes are suitable. However, it becomes clear that further recycling steps (e.g. flotation, hydrometallurgy) can be influenced as well as their product quality and element specific yield.

Fast and Efficient Evaluation of the Mass Composition of Shredded Electrodes from Lithium-Ion Batteries Using 2D Imaging.

With the increasing number of electrical devices, especially electric vehicles, the need for efficient recycling processes of electric components is on the rise. Mechanical recycling of lithium-ion batteries includes the comminution of the electrodes and sorting the particle mixtures to achieve the highest possible purities of the individual material components (e.g., copper and aluminum). An important part of recycling is the quantitative determination of the yield and recovery rate, which is required to adapt the processes to different feed materials. Since this is usually done by sorting individual particles manually before determining the mass of each material, we developed a novel method for automating this evaluation process. The method is based on detecting the different material particles in images based on simple thresholding techniques and analyzing the correlation of the area of each material in the field of view to the mass in the previously prepared samples. This can then be applied to further samples to determine their mass composition. Using this automated method, the process is accelerated, the accuracy is improved compared to a human operator, and the cost of the evaluation process is reduced.