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

Veidenberg, Kristjan; Hovi, Külli; Jõgi, Jaak; Annuk, Andres; Panova, Olga; Hovi, Mart

doi:10.3390/en19143266

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Open AccessArticle

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

by

Kristjan Veidenberg

,

Külli Hovi

,

Jaak Jõgi

,

Andres Annuk

,

Olga Panova

and

Mart Hovi

^*

Institute of Forestry and Engineering, Estonian University of Life Sciences, 51006 Tartu, Estonia

^*

Author to whom correspondence should be addressed.

Energies 2026, 19(14), 3266; https://doi.org/10.3390/en19143266

Submission received: 16 June 2026 / Revised: 3 July 2026 / Accepted: 6 July 2026 / Published: 10 July 2026

(This article belongs to the Section A4: Bio-Energy)

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Abstract

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.

Keywords: DC pulse test; 3-30-3 protocol; diagnostic algorithm; small-capacity cells; e-cigarette waste; effective DC resistance; pre-sorting; circular economy

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MDPI and ACS Style

Veidenberg, K.; Hovi, K.; Jõgi, J.; Annuk, A.; Panova, O.; Hovi, M. Experimental Validation of a Rapid Pre-Sorting Methodology for Small-Capacity Lithium-Ion Cells. Energies 2026, 19, 3266. https://doi.org/10.3390/en19143266

AMA Style

Veidenberg K, Hovi K, Jõgi J, Annuk A, Panova O, Hovi M. Experimental Validation of a Rapid Pre-Sorting Methodology for Small-Capacity Lithium-Ion Cells. Energies. 2026; 19(14):3266. https://doi.org/10.3390/en19143266

Chicago/Turabian Style

Veidenberg, Kristjan, Külli Hovi, Jaak Jõgi, Andres Annuk, Olga Panova, and Mart Hovi. 2026. "Experimental Validation of a Rapid Pre-Sorting Methodology for Small-Capacity Lithium-Ion Cells" Energies 19, no. 14: 3266. https://doi.org/10.3390/en19143266

APA Style

Veidenberg, K., Hovi, K., Jõgi, J., Annuk, A., Panova, O., & Hovi, M. (2026). Experimental Validation of a Rapid Pre-Sorting Methodology for Small-Capacity Lithium-Ion Cells. Energies, 19(14), 3266. https://doi.org/10.3390/en19143266

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

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