From the outside, an industrial-scale battery energy storage system (BESS) often looks like an ordinary shipping container. However, behind that sturdy steel shell lies a complex technology stack, an ecosystem meticulously designed to store and deliver energy in the safest and most efficient way.
It’s more than just a box filled with batteries. A BESS container is a miniature power plant, fully integrated with control systems, energy conversion, thermal management and fire safety. Understanding the internals will help investors and businesses understand the core value and quality differences between suppliers.
1. Protective Shell: Standardized Container
The outer shell is the first line of defense, protecting the sensitive equipment inside from the elements. Using international standard (ISO) containers brings many strategic benefits:
- Modularity: BESS systems are often designed in modular form, neatly arranged in 20-foot or 40-foot containers. This design allows for easy upgrading, maintenance and future expansion of the system.
- Easy Shipping: Compliance with ISO standard dimensions makes BESS transport by road and sea extremely flexible and efficient.
- High Durability: The container shell is made of high-strength steel, has a solid structure, is watertight, light-tight and is coated with high-quality anti-corrosion layers, ensuring long life even in harsh weather conditions.
2. Core Components Inside the Container
Inside the protective shell is a complex system of many components working together. We can divide them into three main groups: the core energy system, the auxiliary system that ensures operation, and the intelligent control system.
2.1. Core Energy System
These are the components directly involved in the process of storing and converting electrical energy.
a. Battery System
This is the “heart” of the BESS, where energy is stored in the form of chemical energy. The system consists of hundreds, even thousands of individual battery cells (usually Lithium-ion technology) connected together.
- Hierarchical structure: The battery cells are assembled into module. Multiple modules are stacked and connected in a rack. Finally, multiple battery racks are connected in parallel or series to form a large battery block, achieving the required voltage and capacity of the entire system.
b. Power Conversion System (PCS)
Batteries store and deliver energy in the form of direct current (DC), while the power grid and most industrial equipment operate on alternating current (AC). PCS, with their main components being bidirectional inverters, act as “interpreters” between these two forms of energy.
- When discharging: PCS converts DC energy from batteries into AC energy to supply loads or feed into the grid.
- When charging: PCS converts AC power from the grid or from a solar system into DC power to charge the battery.
2.2. Vital Support Systems
These are the systems that ensure the core components can operate safely, stably and durably. The quality of these systems is an important factor that determines the life and reliability of the entire BESS.
a. Thermal Management System (HVAC)
Lithium-ion batteries are sensitive to temperature. Operating in environments that are too hot or too cold can degrade performance, shorten lifespan, and, in more serious cases, cause dangerous thermal runaway.
A dedicated HVAC (Heating, Ventilation and Air Conditioning) system is an integral part of maintaining the optimal operating temperature environment inside the container, which usually includes:
- Industrial air conditioners.
- Ventilation and fan systems.
- Temperature sensors are located throughout.
Proper temperature management not only ensures safety but also helps prolong battery life, resulting in better performance for the BESS.
b. Fire Prevention and Fighting System (PCCC)
Fire safety is the top priority in BESS design. Due to the nature of electronic devices and batteries, fire protection systems for BESS containers are usually automatic fire extinguishing systems using clean agents such as FM-200 or Novec 1230.
- Mechanism of action: When smoke, heat or gas sensors detect signs of a problem, the system automatically releases a special gas to extinguish the fire by eliminating the heat element without damaging sensitive electronic equipment.
- Role: This system acts as an important additional layer of protection, activating in the event of a heat runaway, helping to stop the spread of fire and minimize damage.
2.3. Control and Monitoring System (Central Brain)
If the battery system is the heart, then this is the brain and nervous system, coordinating all activities of the BESS.
a. Battery Management System (BMS)
Each battery pack is closely monitored by a BMS. This is considered the “brain of the battery system”. The main task of the BMS is to protect the battery cells from damage by ensuring they always operate within safe limits. The BMS continuously monitors important parameters at the cell, module and system level, including:
- Voltage
- Current
- Temperature
- State of Charge (SoC)
- State of Health (SoH)
A well-designed BMS is a critical component to ensure battery safety and longevity.
b. Energy Management System (EMS)
If BMS manages the battery, then EMS is the brain that controls the entire BESS system. EMS is responsible for deciding when to charge, when to discharge and at what capacity to optimize economic and technical efficiency.
To do this, EMS continuously collects and analyzes data from multiple sources:
- Data from BMS (battery status).
- Data from PCS (inverter status).
- Data from the grid (electricity price, frequency).
- Data from plant loads.
- Data from renewable energy systems (if available).
Based on intelligent algorithms, EMS will control the operation of BESS to perform tasks such as peak load shedding, electricity price arbitrage, or maximizing solar self-consumption.
Illustrative Diagram of Internal Structure of BESS Container
To visualize, imagine a cross-section of a BESS container with the components arranged as follows:
1. Container Shell (ISO Standard): The outer steel shell, with doors and ventilation panels.
2. Battery Racks: Large cabinets containing many battery modules stacked on top of each other take up most of the interior space.
3. Battery Management System (BMS): The control boards and cables are mounted directly on the battery holders.
4. Energy Conversion System (PCS/Inverter): One or more large electrical cabinets, usually located near the outside connection area.
5. Thermal Management System (HVAC): A large industrial air conditioning unit is mounted at one end of the container.
6. Fire Suppression System: Fire extinguisher cylinders and sprinkler systems are installed on the ceiling.
7. Central Control Cabinet (EMS/Controller): The electrical cabinet contains the EMS controller, human-machine interface (HMI) display and communication devices.
A BESS container system is not a collection of discrete devices, but a tightly integrated and synchronized technical solution. From the durable outer container shell to the individual microcircuits in the BMS system, each component plays an indispensable role in ensuring the system operates efficiently, safely and has a long life.
Understanding the detailed internal structure helps businesses have a basis to evaluate quality, reliability and choose a reputable BESS solution provider with real technical capacity.
High-tech container production capacity of Hai Long Construction
- Practical experience with large projects, international standards: Hai Long has successfully implemented many projects to produce electric containers for leading corporations such as Sumitomo Electric Industry (Japan), with products exported directly to demanding markets such as Japan and Korea.
- Modern production process, strict quality control: Each battery container manufactured at Hai Long Construction Factory undergoes a rigorous 6-step process, from material inspection, frame processing, assembly, finishing welding, insulation, cleaning - finishing painting to overall inspection before leaving the factory. A team of skilled engineers and workers ensures that the product meets all technical and safety standards.
- Advanced technology, meeting all technical requirements: Hai Long's electric storage containers integrate large-scale energy storage battery systems, using modern battery technology, intelligent management systems, fire protection, air conditioning and safety protection devices. The product is suitable for renewable energy projects, industry, industrial parks, etc.
- Strong production capacity, large scale: Owning three steel structure factories with a total output of up to 45.000 tons/year, Hai Long can meet special container orders with fast progress, consistent quality and continuous production expansion capability.
