Basic Understanding of Energy Storage Systems

4. Classification of Energy Storage
   Energy storage technology refers to systems or physical media that store energy for later use. Based on storage medium, energy storage technologies can be categorized into:
5. Mechanical Energy Storage:
   • Pumped hydro storage (mature technology, high efficiency, strong regulation capability)
   • Limitations: Geographic dependency, distance from load centers requiring long-distance transmission
6. Electrical Energy Storage:
   • Supercapacitors (ultra-fast charge/discharge, wide operating temperature range, low maintenance)
   • Limitations: Low energy density, high investment costs
7. Electrochemical Energy Storage:
   • Commercial applications: Lead-acid batteries, lead-carbon batteries, lithium batteries
8. Thermal Energy Storage
9. Chemical Energy Storage
10. Electrochemical Energy Storage Power Stations
    Facilities using electrochemical batteries as storage elements for electricity storage, conversion, and release. Composed of multiple electrochemical storage systems of same or different types:
11. Independent energy storage power stations
12. Grid-side or user-side energy storage stations

III. Energy Storage System Diagram

1. Battery System Components
2. Cell: Basic energy storage unit (e.g., lithium-ion cell, lead-acid cell)
3. Module: Intermediate unit between cells and packs, formed by series/parallel connections of cells to meet voltage/capacity requirements
4. Pack: Assembly of multiple cells through series/parallel connections
5. Battery Cluster: Larger unit formed by multiple battery packs to scale up storage capacity
6. Energy Storage System Architecture
7. DC Combiner Cabinet:
   • Parallel connection point for battery clusters, outputting to PCS

2. Power Conversion System (PCS):
   • Comprises bidirectional DC/AC converter and control unit
   • Receives control commands via communication interface
   • Regulates grid active/reactive power based on power instructions
   • Communicates with BMS via CAN interface for battery protection (≥98.5% conversion efficiency)

3. Energy Management System (EMS):
   • Monitoring and optimization software for energy storage systems
   • Features real-time monitoring, data analysis, and dispatch optimization

4. Battery Management System (BMS):
   • Three-tier architecture: Cell management unit → Cluster management → System management
   • Controls charge/discharge based on SOC
   • Triggers circuit breaker for safety when parameters exceed limits (e.g., cell over/under-voltage)

5. State of Charge (SOC):
   • Core BMS parameter indicating remaining energy (percentage of rated capacity)
   • Calculation: SOC = (Remaining Capacity / Rated Capacity) × 100%
   • Example: 12kWh remaining in 20kWh battery = 60% SOC
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Disclaimer: This content is compiled for informational purposes only. All videos, images, and text are non-commercial. Copyright concerns should be reported immediately for removal.