Battery Management Systems (BMS) play a crucial role in ensuring the efficient and safe operation of batteries. They are built upon a three-tier architecture, with each level responsible for specific functions and communication protocols. In this article, we will delve into the details of each level and explore how they work together to optimize battery performance.
First Level: Battery Management Unit (BMU)
The first level, known as the Battery Management Unit (BMU), acts as the control center for individual battery cells. Its primary function is to gather voltage and temperature data from each cell and execute battery balancing strategies. The collected information is then communicated to the second level through communication links, typically utilizing CAN or daisy-chain communication.
Second Level: Rack Battery Management System (RBMS)
At the second level, the Rack Battery Management System (RBMS) takes charge of controlling and managing battery modules. RBMS collects data on module voltage, current, and insulation, controls contactors for battery pack protection, retrieves information from the first-level BMU, and estimates the state of charge (SOC). Communication with the third level occurs through communication links, commonly employing CAN or Ethernet protocols.
Third Level: Stack Battery Management System (SBMS)
The third and final level is the Stack Battery Management System (SBMS), also referred to as the central control unit. SBMS collects information transmitted by the second-level BCU, stores and displays the data, provides real-time alarm capabilities, controls circuit breakers, and offers feedback on contact points. It establishes seamless communication with Power Conversion Systems (PCS), Energy Management Systems (EMS), and local monitoring systems. Furthermore, SBMS facilitates the transparent transmission and control of environmental devices such as air conditioning and fire protection equipment. Communication between SBMS and EMS typically employs Ethernet, while communication with PCS utilizes network ports, 485, or CAN protocols.
Conclusion:
The three-tier architecture of Battery Management Systems ensures efficient and comprehensive monitoring and control of batteries. From the individual cell level to the overall battery stack, each level plays a vital role in data collection, management, and communication. This hierarchical structure enables optimized battery performance, enhanced safety, and seamless integration with power conversion and energy management systems. By understanding the functions and communication protocols of each level, we can appreciate the significant impact of BMS in streamlining energy efficiency and advancing battery technologies.
