ENERGY STORAGE SYSTEM AND OPERATING METHOD THEREOF

In an energy storage system (ESS) including a battery management system (BMS) and a recording device, the BMS obtains operational data of the ESS and generates a first encryption code to guarantee integrity of the operational data to be transmitted to the recording device, and the recording device generates a second encryption code based on the operational data to which the first encryption code is added, to guarantee continuity of operational data received every periods, and generates a third encryption code based on the second encryption code added to the operational data in a period immediately before branching to prevent a series of operational data from being falsified after branching.