Nowadays, many distributed solar power generation systems have been installed around the world. However,there are some problems occurred during running. For example, the power generated cannot be effectively utilized in most of the time. To solve this problem, commercial energy storage system is applied. With the continuous advancement of technology, the maturation of raw materials and the decline in prices, commercial energy storage system is becoming more and more popular now.

This large energy storage system has a PV capacity of 2.5MW, an energy storage capacity of 6.48MW, and a PCS power output of 2.5MW. It is also equipped with a 1MW diesel generation system as a backup.

The ESS mainly consists of battery prefabricated cabin, battery management system (BMS), two-way Power Conversion System (PCS), PV system, EMS, air conditioning system, fire protection system and backup diesel generator etc...

The PV system mainly consists of 4556pcs of 550W solar panel, 20pcs of 125KW on grid inverter and 114 sets of mounting structure. Each set of mounting structure can install 40pcs of solar panels. The wind resistance of the mounting structure is designed based on Category 12 typhoons. In other words, there is no problem as long as the wind speed is lower than 30 meters/second.

Besides the PV system, the most important is our energy storage battery cabins. There are a total of four 20-feet prefabricated containerized cabins (size: 6058*2438*2896mm) for installing 4 sets of energy storage batteries, two-way Power Conversion System, air conditioning system and fire protection system.

The energy storage prefabricated containerized cabin mainly consists of the following systems:

20 feet prefabricated containerized cabin, battery capacity of 1.605 MWh, total 4 cabins of 6.42MWh.Each containerized cabin is equipped with an outdoor electric air conditioner with a cooling capacity of 20KW, and a PACK level automatic fire extinguishing device, as well as a 630KW two-way Power Conversion System (PCS).

At the same time, all lithium batteries are equipped with a battery management system. The core function of the battery management system (BMS) is to monitor and control the charging and discharging process of the battery according to the usage environment, so as to maximize the use of the energy stored in the battery while ensuring battery safety. The battery management system (BMS) consists of three levels: single battery management module (BMU), battery pack/cluster management module (BCMU), and battery stack management system (BAMS), and it is equipped with a display screen. In this project we have a total of 4 BAMS, 32 BCMUs, and 448 BMUs for the entire BMS system.

The energy storage containerized cabin is 20 feet long, has a capacity of 1.6MW, 8 clusters of batteries. Each cluster has 14 PACK boxes and one high-voltage box. The fire protection system is designed with a PACK level protection in accordance with GB-T42288-2022 "Safety Regulations for Electro-chemical Energy Storage Power Stations". A fire extinguishing agent nozzle is installed on each pack box, and there is a solenoid valve at the front of each nozzle. The main engine of the fire extinguishing system is placed at the location reserved by the client.

A composite fire detector is installed in each pack box, and two carbon monoxide and Hydrogen composite detectors are installed on the top of the container. The distance between each detector is less than 4 meters, meeting the standard.

When the detector in a certain pack box issues a level four alarm, the gas fire extinguishing system automatically switches on and sprays gas fire extinguishing agent into the alarming pack box. The agent meets the need for two repeated injections, and each injection is not less than 10 minutes.

Ten minutes after the injection, the water system is turned on and continuously sprays into the pack box through the pipeline of the gas fire extinguishing system. As long as the municipal water supply is sufficient, it won’t stop, which greatly exceeds the standard requirement of 3 hours of continuous suppression.

Last but not least, We configured an EMS monitoring system to realize the collection, display and control of all information in the energy storage power station, complete the execution of dispatching instructions, and realize the preparation and execution of local control strategies. For example,

Monitor and manage the overall operating parameters and status of the equipment
.Battery charge and discharge capacity
.Energy analysis of mains power consumption
.Energy analysis of load power consumption
.Energy analysis of charging power consumption
.Energy analysis of battery discharge consumption
.Activity Alert
.System power curve
This energy storage management system has the advantages of high integration, intelligent management, safety and reliability, system scalability, and can be operated off-grid.

The entire system operating mechanism is as follows:
1. When there is solar power generation, the PV inverter takes the loads, and the surplus power is stored in the energy storage system;
2. When solar is not enough to take the loads, the energy storage system starts to take the loads;
3. When the power of the energy storage system is insufficient, the generator will start to work.

1. Pay attention to transportation measures,
1) The design and manufacturing of our solar ESS comply with relevant international and industry standards, such as ISO container standards, electrical safety standards, etc. Ensure the container cabin has appropriate structural strength and stability, as well as meets electrical safety requirements.
2) Solar ESS is usually equipped with large-capacity battery systems, so battery management is crucial. We adopt advanced battery management system, including battery monitoring, temperature control, overcharge and over-discharge protection and other functions to ensure the safety and stability of the battery.
3) Solar panels are packed in wooden boxes, ensure the safe shipment. if one piece is broken, we promise to send you a new one!!

2. Heat dissipation of containers
Each containerized cabin is equipped with an outdoor electric air conditioner with a cooling capacity of 20KW, and a PACK level automatic fire extinguishing device. The cabin is equipped with a refrigeration product specially developed for battery energy storage containers, applied to electrical, electronic and mechanical components. It is suitable for electro-chemical energy storage charging and discharging in the PACK, which generates a large amount of heat and is sensitive to ambient temperature in a completely isolated energy storage environment. The air conditioner is 20KW, using high-efficiency refrigeration variable frequency compressor technology, standard fan speed adjustment function, dehumidification function, standard electric heating function, RS485 interface, and remote monitoring function of the host computer through MODBUS protocol. It has a auto-start function for incoming calls and provides a variety of alarm and protection functions. LCD display in Chinese and English, convenient for setting parameters and viewing alarm information. R410A is an environmentally friendly refrigerant that complies with RoHS requirements. It can operate normally in a high temperature environment of 50°C and has high reliability. It can operate continuously for more than 10 years, 365 days/year.

3. Application of German solar technology

The solar panels adopt Shingled Craft, innovative design structure, low-temperature adhesive, and high-density layout, which can generate more electricity. The layout is uniform, no welding cracks, low operating temperature, and high pressure resistance. The quality is more stable and the attenuation rate is greatly reduced. High-pressure vacuum seal, protection level reaches IP68. Tempered glass is used on the front of the module to enhance light transmittance and strength. The back is made of high-quality TPT, which can effectively prevent aging and corrosion of internal components. The conversion efficiency can reach to 22%, and the product service life is more than 25 years.

The lithium battery takes the brand-new lithium battery cell from EVE, a well-known domestic brand, with a single cell capacity of 3.2V 280AH. The cell has the characteristics of high cycle life, long storage life, strong environmental adaptability, and high safety. This ESS project we take total 7168 pieces of battery cell. 16 cells in one group, and there are 112 groups in total in one prefabricated cabin. The battery output standard voltage is 716.8V, the operating voltage range is 625V-850V, and the number of cycles can reach over 3500 times.