Experimental Validation of a Rapid Pre-Sorting Methodology for Small-Capacity Lithium-Ion Cells

The reuse of small-capacity lithium-ion cells recovered from disposable e-cigarettes is limited by the lack of rapid and low-cost screening methods. This study evaluates a low-complexity 3-30-3 pre-sorting methodology based on a 30 s DC load pulse and a 3 min rest period applied to series connected cells under identical current conditions. Generic 13350-type cells with a nominal capacity of approximately 850 mAh were tested, and cell suitability was assessed from voltage drop, effective direct-current resistance, and stability over repeated load cycles. In the tested batch, the coefficient of variation of the effective resistance reached 28–35%, indicating substantial cell-to-cell variation within this pilot sample. Repeated loading improved discrimination between stable and degraded cells and enabled selection of a compatible subset for assembly into a 3S3P battery pack. The assembled pack operated successfully as a power source for a FläktWoods 227VM pressure controller in biomass drying monitoring. The proposed method does not replace full battery diagnostics, but it provides a practical first-stage filter that can reduce testing time by more than 90% and improve the safety of second-life cell grouping.