The BMU in the bottom layer is responsible for collecting the relevant information about the battery packs, such as the battery power, the temperature, the SOC, the SOH, the charging current, and the charging voltage, as well as providing this information to the battery information concentrators through the CAN Bus interfaces. After collecting the information from the battery packs, the battery information concentrators regularly upload the information to the XP-8341 battery management platform through the CAN Bus interfaces. Two I-8120Ws devices are used as the CAN Bus communication interface expansion system in each battery information concentrator, where one of the I-8120W modules is responsible for communication with the BMU, while the other is responsible for communication with the battery management platform, whereby, in addition to achieving isolation between the two CAN Bus interfaces, the information from the device is also separated so as to reduce the bus load from the respective CAN Bus domains.
The battery information concentrator not only collects the information from the BMU, but also constantly detects the current and voltage signals fed from the insulation detectors in the battery cabinet through the I-7012F and I-87017W modules, as well as regularly reports the data back to the battery cabinet management platform. As the maximum voltage for the battery cabinet can reach 700 VDC during the charging of the energy storage station, timely detection of the insulation status is required in order to prevent damage to the equipment or even the occurrence of work safety accidents caused by insulation failure.
The battery cabinet management platform not only manages the status of the battery pack in each battery cabinet, but also sends the relevant information to the transmitter through the RS-232 and RS-485 interfaces. In addition, the battery cabinet management platform regularly polls the insulation detectors to determine whether any alarms have been initiated, and performs the On and Off control of the battery relays. In order to prevent any danger caused by the battery relays’ being uncontrollable due to the failure of the battery cabinet management platform, the I-87068W module was especially selected as the DO module to control the battery relays, as it contains an MCU and a watchdog timer. If the battery cabinet management platform is not able to communicate with the I-87068W module for a specific period of time, the module will then output a safety value based on the preset output state configured for each DO in order to prevent any danger caused by the battery cabinet management platform being out of control.
The battery cabinet management platform includes an external Ethernet communication interface through which the information from the battery cabinets in the entire energy storage station can be transmitted to the remote monitoring center for monitoring and control.
To understand the status of each battery cabinet at the site of the energy storage station, all the relevant information from each battery cabinet is accessible either through the screen display for the battery cabinet management platform, or through the screen for the battery information concentrator embedded in the door of each battery cabinet. This can be achieved by switching the pages on the resistive touch screen to display the detailed information from all the battery packs in each battery cabinet, allowing facilitation of daily routine maintenance.
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