Battery energy storage system is a product that absorbs, stores and releases energy in the form of electricity. Energy storage mainly includes thermal energy, kinetic energy, electrical energy, electromagnetic energy, chemical energy and other energy storage, widely used in solar energy utilization, electric power “shift peaks and fill valleys”, waste heat and waste heat recovery, as well as industrial and civil buildings and air-conditioning energy saving and other fields.

First, what is the energy storage system

In the analysis of the energy storage process, in order to determine the object of study and the delineation of part of the object or space range, known as the energy storage system. It includes input and output of energy and matter, energy conversion and storage devices. Energy storage system often involves a variety of energy, a variety of equipment, a variety of substances, a variety of processes, is a complex energy system that changes over time, and requires a number of indicators to describe its performance. Commonly used evaluation indexes are energy storage density, energy storage power, energy storage efficiency, as well as the price of energy storage, the impact on the environment and so on.

Second, the battery energy storage system consists of which parts of the composition

The composition of the energy storage system mainly includes the battery system, PCS converter system, box variable system (if any), station variable system (if any), energy management system and monitoring system (SCADA system), primary and secondary cables and other components.

1、Storage battery system

At present, energy storage is mainly divided into three categories: physical energy storage (pumping energy storage, compressed air energy storage, flywheel energy storage, etc.), chemical energy storage (lead-acid batteries, redox flow batteries, sodium-sulfur batteries, lithium-ion batteries) and electromagnetic energy storage of the three major categories, due to the economy and application scenarios, in addition to pumping energy storage, chemical energy storage is the most widely used, from the point of view of the international and domestic market, the chemical storage of lithium-ion applications More.

2、PCS converter system

Energy storage bi-directional converter referred to as PCS, energy storage converter can realize the AC/DC conversion between the battery and the power grid, complete the bidirectional energy flow between the two, and through the control strategy to achieve the battery system charging and discharging management, network measurement load power tracking, battery storage system charging and discharging power control and normal and islanding mode of operation under the control of the network voltage measurement; has a high conversion efficiency, a wide range of voltage input, fast parallel and off-grid switching and easy maintenance characteristics. Off-grid switching and convenient maintenance, etc., and at the same time, it has perfect protection functions, such as islanding protection, DC over-voltage protection and low-voltage ride-through (optional), etc., to meet the requirements of the system and off-grid.

3、Cabinet substation system (if any)

If the use of high-voltage (6kV, 10kV, 20kV, 35kV, etc.) grid-connected system, must be used to complete the task of boosting box variable, in order to minimize the electromagnetic interference between the two branches and the impact of the circulating current, the box variable system using a double-split transformer, and other parameters with the wind and photovoltaic no big difference.

4、Station substation system (if any)

For the substation equipment to provide alternating current, such as lighting, HVAC, maintenance, protection panels, high-voltage switchgear within the energy storage motor, switch energy storage, living and working facilities power supply, etc., need to operate the power supply. Such as with wind power, photovoltaic and other multi-energy complementary power station, wind power or photovoltaic can be shared with a set of station substation system. At the same time, according to the power load, select the appropriate station variable capacity.

5、Primary and secondary cables

AC ZR-YJV22 or ZR-YJV23 flame-retardant cross-linked polyethylene insulated power cables are characterized by high mechanical strength, good resistance to environmental stress, excellent electrical performance and chemical corrosion resistance, etc. They are light in weight, simple in structure and easy to use. This product is suitable for AC rated voltage 35kV and below on the transmission and distribution lines.

ZR-RVVP control cable low-smoke halogen-free flame retardant cable is characterized by the cable not only has flame retardant properties, but also has a low smoke and harmless (less toxic and corrosive), suitable for the cable flame retardant, smoke density, toxicity index of the special requirements of the place.

6、Battery Management System BMS, Energy Management System EMS

Battery management system BMS, mainly on the battery pack charge and discharge protection management. When fully charged, it can ensure that the voltage difference between the individual batteries is less than the set value, and realize the equal charging of each individual battery in the battery pack, which effectively improves the charging effect under the series charging method. Meanwhile, it detects the over-voltage, under-voltage, over-current, short-circuit and over-temperature status of each single cell in the battery pack, so as to protect and prolong the service life of the batteries.The BMS system is provided with the lithium-ion batteries as a complete set.

Energy Management System (EMS) mainly monitors the real-time operation status information of the power station, including system power curve, battery voltage and temperature information, cumulative processing power information and other agreed monitoring information. And the remote monitoring software can be established in the server to be able to remotely control and download the data, to be able to alarm in real time and transmit to the designated cell phone.

7、Monitoring system, related access system equipment

The basic functions of the battery energy storage monitoring system include: measurement and monitoring function, data processing function, analysis and statistics function, operation control function, event alarm function, protection management function, human-machine interface function, accident memory and history rewinding function, historical data management function, telecommunication and forwarding function, and system maintenance function. I. Technical characteristics of battery energy storage system

Battery energy storage system takes battery as the main equipment, featuring small size, low investment, fast charging, low cost, safety and reliability. Compared with the traditional peak shifting and frequency shifting technologies, the response speed of the battery energy storage system is faster than the coal-fired circulator, with better dynamic regulation capability, making the use of renewable energy more comprehensive and low-cost.

Second, the application of battery energy storage system

1, compensation grid instantaneous imbalance: the battery energy storage system as a compensation product into the power grid, can play a grid frequency regulation, regulation compensation, instantaneous imbalance compensation, etc., to avoid the occurrence of vicious accidents.

2, instead of coal-fired regulation: when the battery energy storage system can replace the traditional coal-fired units to assist grid regulation, renewable energy can be based on the sustainable operation of the grid.

3, support for large-scale online power generation: battery storage system can support large-scale renewable energy (such as wind, solar) online power generation, you can realize more power output, to ensure the safe operation of the grid, and effectively increase the amount of renewable energy power.

4, improve the value of renewable energy power generation insurance: battery storage system can hammer the reliability of renewable energy power generation and the value of insurance, to achieve the improvement of renewable power quality, saving electricity costs, and improve the overall value of the power system can be insured.

Third, the future development of battery energy storage system

Innovative technology is a key factor in promoting the development of renewable power generation and renewable energy storage technology. The development of battery energy storage systems will give rise to a series of new battery energy storage technologies, such as solar energy storage systems, chemical chain energy storage systems, etc., in order to achieve more efficient and reliable renewable power output.

In addition, the development of battery energy storage systems involves the logic of policy regulation, market pricing, technical support, etc. Therefore, government departments also need to formulate more specific and scientific regulatory policies to comprehensively support the development and use of renewable energy.

In conclusion, battery energy storage system is an important energy storage technology for renewable energy, which has changed the familiar renewable power supply mode, promoted the effective use of renewable energy, and laid a solid foundation for the large-scale application of green energy in the future.

Battery storage system is a new type of renewable energy service tool, which combines battery storage technology, software control technology and computer network technology in order to use the technology of storing energy, improve the performance of the power system, extend the service life of the battery, and to realize the effective use of energy in certain equipment.

First, the battery storage system has advantages in storing energy. Battery storage systems can achieve efficient equalization of batteries and energy storage devices, convert cheap energy into expensive electrical energy, and then store it for use when it is not needed. In addition, battery storage systems can efficiently utilize renewable energy sources and reduce energy waste, as well as save on energy production costs.

Secondly, battery storage systems can solve the problem of grid stability. As the current power grid can not keep up with the development of renewable energy, the power generation of renewable energy will fluctuate due to weather changes, which will lead to the problem that enterprises can not generate power instantly. The emergence of energy storage systems can effectively alleviate this phenomenon, can ensure the stability of power delivery, so that the grid terminal power supply is more stable.

Further, battery storage system can reduce the cost of system power supply. Battery storage system can cache the stable power generation, when the need for power generation, you can take out of the stored power, can replace the purchase of market power, which can effectively reduce the cost of system power supply.

In addition, the battery storage system has a good power response ability, can realize the rapid adjustment of power generation, its response time is shorter, can be effectively used for the power balance of the system.

Finally, the battery energy storage system can improve the performance of the battery. Since the battery energy storage system can manage and monitor the battery in a timely manner, it can effectively improve the response of the battery to temperature and charging stress, thus extending the service life of the battery.