In this work, we derive analytical expressions governing state-of-charge and current imbalance dynamics for two parallel-connected batteries. The model, based on equivalent circuits and an affine open circuit voltage relation, describes the evolution of state-of-charge and current imbalance over the course of a complete charge and discharge cycle. Using this framework, we identify the conditions under which an aged battery will experience a higher current magnitude and state-of-charge deviation towards the end of a charge or discharge cycle. This work enables a quantitative understanding of how mismatches in battery capacities and resistances influence imbalance dynamics in parallel-connected battery systems, helping to pave a path forward for battery degradation modeling in heterogeneous battery systems.
@article{arxiv.2211.04961,
title = {Parallel-Connected Battery Current Imbalance Dynamics},
author = {Andrew Weng and Sravan Pannala and Jason B. Siegel and Anna G. Stefanopoulou},
journal= {arXiv preprint arXiv:2211.04961},
year = {2022}
}