Energy storage technology is crucial in driving the development of the new energy industry. Advanced energy storage is not only a fundamental technical basis for building a new energy system and promoting a green and low-carbon energy transition, but it is also key to achieving carbon neutrality and peak carbon emissions. Energy storage systems can eliminate day-night peak-valley differences, ensure smooth output, provide peak shaving and frequency regulation, and serve as backup capacity. This meets the requirements for the stable and safe integration of renewable energy into the grid, significantly reducing wind and solar curtailment.
Here is a typical distributed energy storage system architecture:
The energy storage system is composed of batteries, electrical components, mechanical support, thermal management systems, bidirectional power converters (PCS), energy management systems (EMS), and battery management systems (BMS). The batteries are arranged and assembled into battery modules, which are then fixed into battery cabinets along with other components. Below is an introduction to the key parts of this system.
Battery System
Advanced energy storage batteries, as one of the key technological routes, play an important role in increasing the absorption rate of renewable energy and ensuring the safe and stable operation of the power system. Lithium batteries, as crucial components of energy storage, determine the progress of electrochemical storage. Lithium batteries are divided into lithium iron phosphate batteries and ternary lithium batteries based on the cathode material. The energy storage market mainly uses lithium iron phosphate batteries. Eliminating day-night peak-valley differences is the primary application scenario for energy storage systems, and product lifespan directly affects project returns.
Thermal Management System
If the battery is likened to the body of an energy storage system, the thermal management system is its "clothing." Batteries need to operate in a comfortable temperature range (23~25℃) to achieve optimal efficiency. If the battery's operating temperature exceeds 50℃, its lifespan will rapidly decline; below -10℃, the battery enters a "hibernation" mode and cannot function properly. High temperatures severely impact the lifespan and safety of the energy storage system, while low temperatures can cause the system to cease functioning. The role of the thermal management system is to provide a suitable temperature for the energy storage system based on the ambient temperature, thus extending the system's lifespan.
Battery Management System (BMS)
The Battery Management System (BMS) acts as the link between the battery and the user, primarily to improve battery utilization and prevent overcharging and over-discharging. Voltage, current, and temperature are crucial parameters of the energy storage system. Using complex algorithms, the system's SOC (State of Charge), thermal management system operation, system insulation detection, and battery balancing can be inferred. BMS should prioritize safety in its design, following the principle of "prevention first, control as a guarantee," to systematically address the safety management of the energy storage battery system.
Bidirectional Power Converter (PCS)
The power converter in an energy storage system is similar to a phone charger, converting AC power to DC power for charging. The PCS in an energy storage system is a large-scale charger, but it is bidirectional. It acts as a bridge between the battery stack and the grid, converting AC power from the grid to DC power for the battery stack on one hand, and converting DC power from the battery stack to AC power for feeding back to the grid on the other.
Energy Management System (EMS)
The Energy Management System (EMS) is crucial in an energy storage system. It integrates information from all subsystems within the energy storage system, fully controlling the system's operation and making relevant decisions to ensure safe operation. EMS uploads data to the cloud, providing operational tools for the operator's backend management personnel. It also facilitates direct interaction with users. Maintenance personnel can use EMS to monitor the energy storage system's operation in real-time, achieving real-time supervision.