Minimum lithium plating overpotential control based charging strategy for parallel battery module prevents side reactions

As demands for massive energy consumption inevitably grow, lithium-ion batteries have been widely recognized as promising energy devices and fundamental components for electric vehicles or grid application. However, certain circuit configuration especially parallel connection exhibits highly heterogeneous current distributions in different branches, some of which undertakes considerable current fluctuation during charge/discharge. Therefore, a charging strategy for integrated energy storage facilities is highly desirable to avoid the side reactions like lithium plating that can cause severe degradation or even risks of thermal runaway. In this study, a parallel-module model is established based on a modified single particle model with side reactions, and experimentally validated under various C-rates. Then a minimum Li plating overpotential control (MLPOC) based charging strategy is proposed for this parallel-module model and effectiveness for reducing capacity loss is verified by module simulations under high C-rate charging. Furthermore, parameter sensitivity of resistance ratio between branch and interconnect resistances on module performance with or without MLPOC are investigated. Results show that a medium resistance ratio of 20?30 is recommended for this parallel module. The insights from this paper not only provide charging strategy with minor degradation but also guide the design of battery module for better pack charging performance.

Automated summary

This study establishes a parallel-module model for lithium-ion batteries and proposes a charging strategy based on minimum Li plating overpotential control (MLPOC) to reduce capacity loss. The research also investigates the sensitivity of resistance ratio between branch and interconnect resistances on module performance. Results show that a medium resistance ratio of 20-30 is recommended for optimal module performance.