Main content:
A complete electrochemical energy storage system is mainly composed of: battery pack, battery management system (BMS), energy management system (EMS), power conversion system (PCS) and other electrical equipment. The energy management system is suitable for system monitoring, power control and energy management monitoring systems of energy storage stations, micro-grids, new energy storage integration and other types of projects.
The energy management system realizes centralized monitoring of the BMS and PCS of the energy storage power station, unifies operation, maintenance, repair and management, realizes rapid fault removal, relieves pressure on the power grid during peak loads, reduces power grid operating costs, and improves economic benefits.
1. What is EMS?
EMS is an energy management system for energy storage. It generally refers to an integrated energy management system for energy storage power plants in lithium batteries such as lifepo4 battery, ternary lithium battery, etc. It realizes real-time monitoring, diagnosis and early warning, panoramic analysis, and advanced control functions, meets the needs of comprehensive operation monitoring, intelligent security analysis, and dynamic panoramic analysis, and ensures the safe, reliable, and stable operation of energy storage power stations.
Energy Management System is the decision-making center of the energy storage system. Energy management systems include grid-level energy management system and micro-grid-level energy management system. The EMS mentioned in energy storage systems generally refers to micro-grid levels.
2. What is BMS?
BMS means battery management system. As the decision-making system for battery management, BMS is the brain of the energy storage system. The energy storage system participates in the decision-making and management of the energy storage battery through the BMS.
The BMS acts as the sensing role in the energy storage system. Its main function is to monitor the operating status of each battery in the battery energy storage unit to ensure the safe operation of the energy storage unit.
3. The composition of the energy management system is different from BMS
The composition of the energy management system and BMS in the energy storage system is different. The composition of energy management system mainly includes device layer, communication layer, information layer and application layer. The BMS is mainly composed of three layers, and the hardware is mainly divided into slave control unit, main control unit and master control unit.
① The composition of the energy management system
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Compositions |
Functions |
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Device layer |
Energy harvesting conversion (PCS, BMS) is required for support |
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Communication layer |
Mainly includes link, protocol, transmission, etc. |
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Information layer |
Mainly includes cache middleware, database, and server, among which the database system is responsible for data processing and data storage, records real-time data and important historical data, and provides historical information query |
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Application layer |
The form of expression includes APP, Web, etc. Provide managers with a visual monitoring and operation interface. Specific functions include energy conversion decision-making, energy data transmission and collection, real-time monitoring and control, operation and maintenance management analysis, visual analysis of electric energy/electricity, remote real-time control, etc. |
② The composition of BMS
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Compositions |
Functions |
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Bottom layer |
The slave control BMU, which is the management layer of single battery. Consisting of a battery monitoring chip and its auxiliary circuits, it is responsible for collecting various information of the single battery, calculating and analyzing the SOC and SOH of the battery, realizing active balancing of the single battery, and uploading the abnormal information of the single battery to the main control |
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Middle layer |
The main control BCU, which is the management layer of the battery pack. Collect various single battery information uploaded by BMU, and collect battery pack information. Calculate and analyze the SOC and SOH of the battery pack |
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Upper layer |
The master control, which is the battery cluster management layer. Responsible for the overall coordination within the system and the external information interaction with EMS and PCS, and control the operation process of the entire BMS system according to external requests |
4. The functions of energy management system and BMS are different
① Functions of energy management system
System master control
Mainly through the first real-time data collection and monitoring. Including the key operation information of the energy storage station: including the rated power of the power station, the rated capacity of the power station, the number of operating PCS of the power station, and the operation data sent by the energy storage station, to analyze the operating status of the system, and to mine or extract useful information. Such as energy storage system SOC, SOH, energy storage charge and discharge efficiency, etc.
Second, the map shows the geographical location of the energy storage station. The third is to display the recent historical data: today’s and yesterday’s peak-shaving power curves, this month’s, this week’s, yesterday’s, and 24-hour charging and discharging active power curves.
Monitor and control
- One is to display the current charging and discharging status of the energy storage station, as well as related key data.
- The second is to summarize the accidents of multiple energy storage units under the energy storage power station, which can be viewed in detail by clicking on the light plate.
- The third is the display data of energy storage power stations under planned control, including real-time charge and discharge curves, day-to-day plan curves, and intraday ultra-short-term curves.
Plan ahead
One is charge and discharge plan maintenance: this page displays to users the charge and discharge plan of the energy storage station, the new energy forecast information curve and the energy storage charge and discharge information curve. The user can add, modify and delete the charging and discharging plan of the energy storage station in the column of "Maintenance of Charge and Discharge Plan".
The control strategy of peak shaving and valley filling, new energy consumption, peak shaving and valley filling with consideration of new energy consumption, and emergency power protection can be implemented through charging-one-discharge, two-charge-two-discharge, or one-charge-two-discharge modes.
The second is historical plan query: query the dispatch plan value of the corresponding time period or the energy storage charge and discharge plan value automatically generated by the system through date selection.
Alarm query
Users can query and export historical alarm information through the alarm interface. Accurately and easily search for historical alarm information without searching through the system every time.
② Functions of BMS
BMS plays the role of perception in the energy storage system, and its main function is to monitor the operating status of each battery in the battery energy storage unit to ensure the safe operation of the energy storage unit. BMS measures the basic parameters of the battery. For example, in 12v battery, BMS can measure its voltage, current, temperature, etc., to prevent overcharging and overdischarging of the battery and prolong the service life of the battery.
BMS needs to calculate and analyze the SOC (battery remaining capacity) and SOH (battery state of health) of the battery, and report abnormal information in time. BMS is an important guarantee for the safety, long life and low cost of energy storage systems.
At present, the functions of BMS have developed from basic functions such as monitoring, communication, protection, display, and storage to advanced functions such as battery system safety diagnosis, long-life operation and maintenance, and system economic index diagnosis. In particular, BMS equipment is an important part of building a cloud-edge combined energy storage system big data platform and deep mining and analysis functions.
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