All-in-one design, integrated liquid cooling battery pack, battery management system BMS, energy management system EMS, modular PCS and ?re protection system in one. The system is equipped with transformers and switchgear. The system can be combined with photovoltaic power generation to form a grid-tied solar with energy storage system. Multiple systems can be connected in parallel for ?exible expansion. The system is suitable for a variety of applications such as, on-grid/o?-grid solar energy and storage system, backup power supply, and solar diesel-microgrid system.