(1) The energy storage system is composed of lithium iron phosphate battery cabinet, PCs, control cabinet, temperature control system and fire protection system, which are integrated in a 20 foot container. It includes 3 battery cabinets and 1 control cabinet. The system topology is shown below
(2) The battery cell of the battery cabinet is composed of 1p * 14s * 16S series and parallel mode, including 16 lithium iron phosphate battery boxes and 1 main control box.
(3) The battery management system is divided into three levels: CSC, sbmu and mbmu. CSC is located in the battery box to complete the data acquisition of the information of individual cells in the battery box, upload the data to sbmu, and complete the equalization between individual cells in the battery box according to the instructions issued by sbmu. Located in the main control box, the sbmu is responsible for the management of the battery cabinet, receiving the detailed data uploaded by the CSC inside the battery cabinet, sampling the voltage and current of the battery cabinet, calculating and correcting the SOC, managing the pre charge and charge discharge of the battery cabinet, and uploading the relevant data to the mbmu. Mbmu is installed in the control box. Mbmu is responsible for the operation and management of the whole battery system, receives the data uploaded by sbmu, analyzes and processes it, and transmits the battery system data to PCs. Mbmu communicates with PCs through can communication mode. See Appendix 1 for communication protocol; Mbmu communicates with the upper computer of the battery through can communication. The following figure is the communication diagram of the battery management system

Operating Conditions of The Energy Storage System
The design maximum charge rate and discharge rate do not exceed 0.5C. During testing and use, Party A is not allowed to exceed the charging and discharging rate and operating temperature conditions stipulated in this agreement. If it is used beyond the conditions specified by Party B, Party B will not be responsible for free quality assurance of this battery system. In order to meet the technical requirements of the number of cycles, the system requires no more than 0.5C for charging and discharging, the interval between each charging and discharging is more than 5 hours, and the number of charging and discharging cycles within 24 hours is no more than 2 times. The operating conditions within 24 hours are as follows