Data for A study of cell-to-cell interactions and degradation in parallel strings : implications for the battery management system

The self-balancing characteristic of parallel cells allows a battery management system (BMS) to approximate the cells as one equivalent cell with a single state of health (SoH) value, estimated either as capacity fade (SoHE) or resistance increase (SoHP). A single SoH value is however not applicable if the initial SoH of each cell is different, which can occur when cell properties change due to inconsistent manufacturing processes or in-homogeneous operating environments.

As such this work quantifies the convergence of SoHE and SoHP due to initial differences in cell SoH and examines the convergence factors. Four 3 Ah 18650 cells connected in parallel at 25 °C are aged by charging and discharging for 500 cycles. For an initial SoHE difference of 40% and SoHP difference of 45%, SoHE converge to 10% and SoHP to 30% by the end of the experiment.