Electricity is indispensable energy in our daily life. It is no exaggeration to say that all our production and life will turn into paralysis mode if there is no electricity, therefore, electricity plays a pivotal role in our production and life!
Most of the time, electricity is behind the requirement, so solar system energy storage technology is also very necessary, what is battery energy storage technology, what kind of the role does it play and what are the structures of it?
Battery energy storage technology and energy development industry is inseparable, battery energy storage technology can well solve the poor day and night electricity peak valley issues to achieve stable output, peak frequency modulation and reserve capacity, in order to meet the demands of stable new energy power generation and safe access to the power grid, in the meanwhile, it also can reduce the wind abandonment, light abandonment and other phenomenon.
(1) The structures of battery energy storage technology
The energy storage system consists of batteries, electrical components, mechanical supports, heating and cooling systems (thermal management systems), bi-directional energy storage converters (PCS), energy management systems (EMS) and lithium battery management system (BMS).
Batteries are arranged and connected to assemble into battery modules, then it is fixed and assembled into the cabinet with other components to form a battery cabinet. We will introduce some of the most important parts here.
The energy mode battery used in battery energy storage system is different from the energy mode battery. If you take professional athletes for example, the power mode battery is like a sprinter, they have good explosive power and the high power can be released in a short time
On the other hand, the energy mode battery is more like marathon runners, they are with high energy density and a single charge can provide longer service time.
Another characteristic of energy mode batteries is their long service life, which is very important for battery energy storage systems. The elimination of day and night peak-valley difference is the main application scenario of energy storage system, the product service time directly affects the revenue of the project.
2. Thermal management
If we think the battery is like the body of the energy storage system, then the thermal management system is the “clothes” of the energy storage system. Batteries are the same as people, they also need to be kept at a comfortable temperature (23-25 ° C) to work more efficiently.
If the operating temperature of the battery exceeds 50 ° C, the battery life will deteriorate rapidly. When the temperature drops below -10℃, the battery will enter “hibernation” mode and can not work properly.
It shows from the different performance of the battery in the face of high temperature and low temperature, the service life and safety of the battery energy storage system in the high temperature state will be greatly affected, while the energy storage system in the low temperature state will completely stop working.
The role of thermal management is to give the energy storage system a comfortable temperature based on the surrounding environment temperature. Thereby, the whole system can get “prolong life”.
3. Battery management system BMS
Battery management system, it can be regarded as the commander of the battery system and the link between the battery and the user, it is mainly in order to improve the utilization rate of the battery and it prevents the battery overcharging and excessive discharge.
BMS should be designed with safety as the original intention, follow the principle of “prevention first, control and guarantee”, it systematically solve the safety control of battery energy storage system.
4. Bidirectional energy storage converter(PCS)
The function of mobile phone charger is to convert 220V alternating current in the household socket into 5V~10V direct current required by the mobile phone battery. This is consistent with the way battery energy storage systems convert alternating current to the direct current required by the battery stack during charging.
PCS energy storage system can be understood as an oversized charger, but the difference from a phone charger is that it is two-way. Two-way PCS acts as a bridge between the battery stack and the power grid end. On the one hand, the alternating current power at the power grid end is converted into direct current to charge the battery stack; on the other hand, the direct current of the battery stack is converted into alternating current power and fed back to the power grid.
5. Energy management system EMS
A distributed energy resource researcher once said that “a good plan comes from the top-level design, a good system comes from EMS”, which shows the importance of EMS in battery energy storage system.
The existence of energy management system is to summarize the information of each subsystem in the energy storage system, comprehensively control the operation of the whole system and make relevant decisions to ensure the safe operation of the system.
The EMS will upload the data to the cloud and provide operation tools for background administrative staff of the carriers. In the meanwhile, EMS is responsible for direct interaction with users. The operation and maintenance personnel for the users can check the running status of battery energy storage system in real time through EMS to implement supervision.