Battery Passport and Early Diagnostics for Second-Life Lithium-Ion Battery Screening: A Data Leakage-Aware, Pack-Grouped Evaluation

Screening of retired lithium ion cells limits second-life deployment, because full characterization resolves retention well yet occupies a test channel for hundreds of hours per cell. This study measures how much screening information each chronologically available block carries once the physical grouping of retired cells is respected, using a primary source with 1034 retired notebook cell records from 152 retired notebook packs, of which 100 cells carry delayed capacity trajectories, and a stored pack yield summary excluded as outcome derived. Holding out whole packs, battery history reaches 0.686 balanced accuracy for source-defined second-life eligibility, physical observations 0.761, and early electrical diagnostics 0.862; the paired bootstrap interval for that last step excludes zero, the balanced error rate falls by 56 percent, and false rejections fall from 17 to 6 of 36 eligible cells. The ordering holds at any matched threshold, where the early block never produces more false rejections than history alone, and in an independent 86 cell NCM(523)/graphite cohort, five explicit diagnostics raise holdout accuracy from 0.660 to 0.743 whereas 108 implicit features reach 0.627. Screening therefore benefits from a staged design: history provides a first pass, early diagnostics refine the decision, and full characterization qualifies.