When analyzing the energy storage process, the portion of objects or spatial ranges delineated to determine the research object is called an energy storage system. It includes input and output of energy and matter, as well as devices for energy conversion and storage. Energy storage systems often involve multiple types of energy, devices, substances, and processes, and are complex energy systems that vary over time, requiring multiple indicators to describe their performance. The commonly used uation indicators include energy storage density, energy storage power, energy storage efficiency, energy storage price, and impact on the environment.