Key Points for Safe Design of Container Energy Storage Systems,Safety Points for Industrial and Commercial Energy Storage Systems

Container energy storage systems have huge battery capacities, usually starting at MWh. Once a safety accident occurs, the consequences are very serious. Therefore, both domestic (GB) and international standards have many mandatory standards for the safety of large energy storage systems.

Key Points for Safe Design of Container Energy Storage Systems,Safety Points for Industrial and Commercial Energy Storage Systems

Safe Design of Container Energy Storage Systems

The safe design of container energy storage systems includes multiple aspects:

1.System Design:

The preliminary top-level system design is also particularly important for the safety of the entire energy storage system, including the selection of battery cells (brand and grade), the type of BMS/EMS, and the matching of fire protection. The system design can be said to determine the DNA of the entire energy storage system.

System Design:

2.Electrical Safety:

The electrical safety of containers is one of their important safety indicators. In the design of electrical safety, it is necessary to fully consider factors such as electrical safety standards and electrical safety protection measures to improve its electrical safety performance.

Protection Configuration of Energy Storage Units:

Over/under voltage protection, thermal protection, overcurrent protection, voltage and current change rate protection, and charging protection.

Protection Configuration of DC Connection Units:

Configure fuses, low-voltage DC circuit breakers, low-voltage DC isolating switches, and mid-span battery protection. For multiple energy storage units, the DC connection units should be connected separately as much as possible to avoid losing more power capacity in case of failure.

Protection Configuration of Bi-directional Converters (PCS):

Over/under voltage protection, over/under frequency protection, phase sequence detection and protection, anti-islanding protection, overheating protection, overload and short circuit protection.

Electrical Safety

3.Fireproof Performance:

The fireproof performance of containers is one of their important safety indicators. In the design of fireproof performance, it is necessary to fully consider factors such as fireproof standards and fireproof materials to improve its fireproof performance.

4.Modular Energy Storage Technology

New Modular Energy Storage Technology, each battery module is equipped with a BMS battery management system.Equipped with multiple functions such as electrical and physical dual isolation, automatic fault module exit, and battery insulation failure warning.Ensures the safety and reliability of lithium batteries.Module self-adaptive active equalization.Supports the mixed use of cascade batteries and different brands of batteries.Supports staged expansion and minute-level maintenance. Solves many application problems of lithium batteries in one fell swoop.

Fire Control System Design

5.Fire Control System Design

In practice, a hierarchical mechanism is generally adopted for energy storage fire thermal runaway.

The first-level strategy is fire alarm. It detects and perceives the change of gas concentration in the energy storage box through gas alarm detectors.

The second-level strategy is to automatically turn off the air conditioner and start the exhaust fan when the smoke detection system detects that thermal runaway is about to occur, to avoid the formation of overpressure due to excessive concentration of combustible gas in the cabin.

The third-level strategy is fire alarm. When the temperature and smoke sensor detects a fire in the cabin, it automatically cuts off the power and starts the fire extinguishing system.

The cabin fire system design and Anshun Fire Protection have proposed the principle of "power off first, fire fighting later, and continuous suppression" in repeated long-term experiments.

The integrated fire fighting device in the container adopts a three-level or higher architecture, including early warning, alarm, and action. The fire fighting system includes detection controller, fire control box, sound and light alarm bell/lamp, temperature and salt fog sensor, and perfluorohexane gas fire extinguishing device.

In order to meet the normal use of battery packs and supporting equipment under the environmental conditions of the project site and the operating conditions of the system, the container performs thermal management control through the following aspects, mainly including air conditioning, thermal management design, and insulation layer. The thermal management system ensures that the temperature inside the container can guarantee the normal operation of the battery pack and supporting electrical equipment.

The temperature control scheme inside the container is as follows:

The temperature at each set point inside the container is monitored in real time by the temperature probe. When the temperature at the set point is higher than the set start temperature of the air conditioner, the air conditioner runs the cooling function and cools the inside of the container through a special air duct. When the temperature reaches the lower limit of the set value, the air conditioner stops working.

6.System Installation Layout

The installation layout of the energy storage system must meet the fire distance or firewall requirements specified in local standards, such as, but not limited to, the "GB 51048-2014 Electrochemical Energy Storage Power Station Design Specification".

7.Regular Inspection

The energy storage system should be inspected for fire safety regularly, no less than once a month. When inspecting the system with power on, pay attention to the hazard warning signs on the equipment and avoid standing in front of the cabinet door. After the power components of the energy storage system are replaced or the wiring is changed, you must manually start the wiring detection and topology identification to avoid abnormal system operation.

  1. User-provided video device

It is recommended that users provide their own video device to record the detailed process of installation, operation and maintenance of the equipment.

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