Extending Life of Lithium-Ion Battery Systems by Embracing Heterogeneities via an Optimal Control-Based Active Balancing Strategy

This article formulates and solves a multiobjective fast charging-minimum degradation optimal control problem (OCP) for lithium-ion battery module made of series-connected cells equipped with an active balancing circuitry. The in the are subject to heterogeneity induced by manufacturing defects nonuniform operating conditions. Each cell is expressed via coupled nonlinear electrochemical, thermal, aging model direct collocation approach employed transcribe OCP into programming (NLP). proposed formulated under two different schemes charging operation: 1) same time (OCP-SCT) 2) (OCP-DCT). former assumes simultaneous all irrespective their initial conditions, whereas latter allows times account heterogeneous solved intrinsic among them terms state charge health. Results show that OCP-DCT scheme provides more flexibility deal heterogeneity, boasting lower temperature increase, current amplitudes, degradation. Finally, comparison common practice constant (CC) over long-term cycling operation shows promising savings, retained capacity, attainable both (OCP-SCT OCP-DCT) schemes.