With the increasing penetration of renewable energy, distributed energy storage systems play a crucial role in enhancing grid stability and energy utilization efficiency. This study aims to improve the operational efficiency and reliability of energy storage systems, focusing on a dual-mode switching photovoltaic-storage system. A detailed model of the energy storage system was established, utilizing a half-bridge bidirectional DC/DC converter topology. A dual-mode control strategy for Buck charging and Boost discharging was designed, incorporating an SOC protection mechanism. Simulation results demonstrated that the system achieves smooth switching between charging and discharging modes, with good dynamic response, stable voltage, and power output. The SOC protection function promptly cuts off the circuit when the battery state of charge reaches 98%, and the system model effectively prevents overcharging and over-discharging. This study verifies the effectiveness and engineering practicality of the proposed control strategy, providing a theoretical basis and technical reference for the optimal operation of distributed energy storage systems.