A battery energy storage system (BESS) is a relatively complex integrated power unit constructed by integrating energy storage batteries, power conversion devices, local controllers, power distribution systems, temperature and fire safety systems, and other related equipment according to specific application requirements. Its basic characteristics include:
- 1) The internal devices within the BESS (Battery Energy Storage System) have clearly defined roles and are interconnected, working together to achieve energy, power, and voltage control at the BESS grid connection point or output port, under the premise of safety, efficiency, and long lifespan.
- 2) The safety and lifespan of the energy storage batteries in the BESS largely determine the safety and lifespan of the entire system, and they have stringent technical requirements regarding the operating environment, making them a key aspect that must be considered during the internal system design.
- 3) The power conversion device in the BESS (Battery Energy Storage System) is a critical node for the entire energy storage system's power exchange with the external grid. Its performance directly reflects the BESS's operating mode, control accuracy, response speed, and grid-friendliness, and also influences the customer's most intuitive user experience of the energy storage system in a short period of time.
The energy storage batteries
- 4) The energy storage batteries, power conversion devices, and equipment such as air conditioning and fire protection systems each have their own independent controllers to achieve self-operation, alarming, or protection. However, the implementation of system functions, the linkage and coordination between equipment, start-up and fault protection operations, external communication, and effective information transmission are all handled by a local controller, enabling the energy storage system to participate in grid dispatch or achieve project application objectives as a whole.
- 5) The energy storage system, acting as a unified external and autonomous internal power execution unit, receives scheduling commands from the upper-level energy management system and executes power or mode control instructions. Therefore, it should possess rich external communication interfaces and flexible, diverse operating modes. Through functions such as on-demand energy transfer, rapid power ramping, and voltage stabilization control, it improves the overall operational performance of power generation, power grids, and load applications, thereby demonstrating its value.
- 6) Control and management are crucial for the energy storage system to realize its value, and this largely depends on the system integrator's understanding of the existing systems, controls, and development trends in the application field. From this perspective, considering the energy storage system as an "energy patch" or "flexible upgrade" to the existing power system is quite reasonable.
Limited by the capacity of the battery itself
Limited by the capacity of the battery itself and the development level of power electronic conversion devices, BESS (Battery Energy Storage Systems) have always faced a contradiction between safety and efficiency on the one hand, and high energy density and diverse, complex functions on the other. Particularly with their large-scale application in renewable energy generation and grid-side applications, the overall capacity and voltage levels of energy storage systems are continuously increasing, the communication architecture is becoming more extensive, and the electromagnetic environment is becoming more complex. These factors pose serious challenges to energy storage systems and their integration technologies.
- 1) How to comprehensively master the relevant industry application background theory and technology, and configure an effective and reasonable energy storage system capacity and power; how to adopt targeted control schemes to achieve seamless integration with existing systems while fulfilling the overall project application objectives.
- 2) How to determine the specific technical parameters, functional requirements, and performance indicators of the energy storage system based on the project's application technical characteristics, and accordingly select key internal equipment of the energy storage system, such as PCS and batteries.
- 3) How to conduct electrical design of the energy storage system to ensure electrical safety, hierarchical protection, and grid-friendliness of the internal equipment, given the increasing capacity and voltage levels of the energy storage system.
- 4) How to select and calculate the parameters and installation layout of internal environmental control equipment and safety and fire protection equipment for energy storage systems, focusing on battery life and safety, to achieve uniform temperature distribution and heat dissipation for large-capacity, high-energy-density batteries while minimizing land area.
- 5) How to collaboratively manage the diverse equipment within the energy storage system to fully utilize the functions and performance of each device and ensure energy storage requirements. This includes optimizing overall system performance and avoiding performance degradation due to unreasonable integration methods; and how to achieve collaborative protection in fault conditions to prevent a single equipment failure from escalating or spreading, with particular attention to the linkage and isolation between electrical equipment and battery equipment to avoid problems such as arcing, localized heat accumulation, and damage or explosion of electrical components that could compromise battery safety.
How to build internal and external communication architectures
- 6) How to build internal and external communication architectures and data models for energy storage systems applicable to different application scenarios, enabling standardized communication access and data exchange between internal devices, facilitating the overall energy storage system's reception of commands and transmission of information to the upper-level management system, and achieving decoupled communication of fast control commands and potentially large amounts of internal data, such as battery cell data, to avoid control delays or interference.
- 7) How to build larger-scale energy storage projects or power plants by connecting modular energy storage systems in parallel, and how to eliminate individual performance differences between energy storage systems through station-level management and control, avoiding cross-coupling and mutual interference between energy storage systems during rapid scheduling and transient transitions, ensuring stable operation within the overall power plant, controlled energy flow with the power grid, and rapid information exchange and command execution with the upper-level control system.
- 8) How to complete the integration, installation, and commissioning of internal equipment in the energy storage system based on existing electrical, fire protection, and BESS (Battery Energy Storage System) engineering installation standards, minimizing on-site operations or frequent movement of battery packs, and avoiding unsuitable installation platforms or grounding methods that could lead to a reduction in the energy storage system's protection level or introduce instability factors.
- 9) How to apply advanced technologies such as artificial intelligence and blockchain to energy storage systems to improve their intelligent management, lifespan prediction, early fault warning, and diagnostic capabilities, thereby effectively improving users' understanding of the current and future performance and operational expectations of the energy storage system, and providing a crucial hardware foundation and implementation means for the realization of advanced system scheduling and energy management technologies such as smart grids and virtual power plants.
Due to the inherent complexity of energy storage systems, the specialized nature of external applications, and the high demands on equipment safety, energy storage system integration technology has become the specific implementation method and necessary technological bridge connecting underlying equipment (batteries, PCS, etc.) with application fields.