CLASSIFICATION AND DESIGN OF ENERGY STORAGE CONTAINERS

Classification of Energy Storage Containers by Material:

Aluminum Alloy Container:

Advantages: Lightweight, aesthetically pleasing, corrosion-resistant, flexible, easy to process, low processing and repair costs, long service life.

Disadvantages: High cost, poor welding performance.

Steel Container:

Advantages: High strength, sturdy structure, high welding performance, good water tightness, low cost.

Disadvantages: Heavy weight, poor corrosion resistance.

Fiberglass Reinforced Plastic (FRP) Container:

Advantages: High strength, good rigidity, large volume, good thermal insulation, corrosion resistance, chemical resistance, easy to clean, easy to repair.

Disadvantages: Heavy weight, susceptibility to aging, reduced strength at bolted joints.

Design of Energy Storage Containers:

Battery Compartment:

Components include batteries, battery racks, Battery Management System (BMS) control cabinet, heptafluoropropane fire suppression cabinet, cooling air conditioning, smoke detection lighting, surveillance cameras, etc.

Battery types may include iron-lithium batteries, lithium batteries, lead-carbon batteries, and lead-acid batteries.

Cooling air conditioning adjusts in real-time based on the compartment temperature.

Surveillance cameras enable remote monitoring of equipment status.

The BMS system manages and monitors battery status remotely.

Equipment Compartment:

Includes Power Conversion System (PCS) and Energy Management System (EMS) control cabinets.

PCS controls charging and discharging processes, performs AC/DC conversion, and can supply AC loads directly in off-grid situations.

EMS is crucial for monitoring and controlling power distribution, evaluating the power system’s status, and automatic generation control.

For a 1 MWh system, the ratio of PCS to battery can be 1:1 or 1:4 (e.g., 250 kWh PCS with 1 MWh battery). The design features front-to-back airflow for heat dissipation, optimizing internal distribution systems for easy transport and reduced maintenance costs.

Example of a 1 MW/1 MWh Containerized Energy Storage System:

Battery System:

Comprises series-parallel arrangements of battery cells.

Battery cells form battery modules, modules are connected in series to create battery packs, and packs are connected in parallel to increase system capacity.

Integrated and installed in a battery cabinet.

Monitoring System:

Facilitates external communication, network data monitoring, data collection, analysis, and processing.

Ensures accurate monitoring, high precision in voltage and current sampling, and fast synchronization of data and remote command execution.

The Battery Management Unit (BMU) ensures voltage balance and prevents circulation between battery modules.

Fire Suppression System:

Specialized system for safety.

Equipped with smoke sensors, temperature sensors, humidity sensors, emergency lights, etc.

Automatically detects and extinguishes fires; the dedicated air conditioning system maintains a suitable temperature range.

Energy Storage Inverter:

Converts DC power from batteries to three-phase AC power.

Operates in grid-connected and off-grid modes.

In grid-connected mode, the inverter interacts with the grid based on power commands.

In off-grid mode, it provides voltage and frequency support for on-site loads and startup power for some renewable energy sources.

Connected to the isolation transformer to ensure electrical insulation and maximize system safety.

The entire system, including the energy storage battery system, monitoring system, battery management unit, dedicated fire suppression system, specialized air conditioning, energy storage inverter, and isolation transformer, is integrated into a 40-foot container.