Scalable Modular Energy Storage Solutions for Enhanced Local Grid Flexibility at Ports

This paper introduces scalable modular energy storage solutions designed to boost port flexibility by integrating healthy and second-life batteries into power grids. The use of Second-Life Batteries (SLB) offers a sustainable, cost-effective alternative to new batteries, addressing both economic and environmental concerns. We employ a Modular Multilevel Converter (MMC) with battery packs in each submodule, enabling easy maintenance, upgrades, and replacement of degraded batteries. Key innovations include a $\boldsymbol{dq}$ current controller, a circulating current controller, and a Constant Current-Constant Voltage (CC-CV) protocol for effective battery management. Simulations with a Thevenin equivalent battery model validate the system's performance in both charging and discharging, showcasing the potential of second-life batteries to transform port electrification through modular, efficient energy storage solutions.