To provide energy storage technology solutions for the safe operation of distribution networks

491 kilowatts, 746 amps... .. On April 15, Zhu Shuai, a member of the research team of Energy Storage Application Technology at the New Energy Research Center of China Electric Power Research Institute, recorded the charging data of the 500kw 500kw mobile energy storage vehicle. These data can help the energy storage application research team to study the efficiency of the energy storage system, which is valuable for evaluating the economics and security of mobile energy storage.

The research team of energy storage application technology at the new energy research center of the Chinese Academy of Electrical and Electronic Sciences (Caer) has been pursuing application-oriented R & D. since 2012, they have developed a series of mobile energy storage power vehicles, power coverage of 30 kilowatt-500 kilowatt-hour, capacity coverage of 50 kilowatt-hour-1000 kilowatt-hour. These mobile energy storage power supply vehicles can ensure the safety and stability of the premise, with the completion of non-power distribution network operations, for the safe and stable operation of the distribution network to contribute“Energy Storage Wisdom.”.

Building a modular platform to develop mobile energy storage power car

On March 5, two 500kw-500kwh mobile energy storage vehicles smoothly alternated power supply for residents at a non-blackout operation site in Changzhou, Jiangsu province. Su Hua, head of the Communist Party service team at Changzhou's Jiangsu Electric Power, said the operation would take 10 hours without a power cut, with two mobile energy storage vehicles and one serving as a constant power supply for the temporary bus, another vehicle as a mobile power supply, low-voltage cable box to and from the community, with live work, the residents will load“Transport” to the temporary bus.

In the past, power supply companies mainly provided temporary power supply through diesel-powered generation vehicles, but the diesel-powered generation vehicles exist noise, exhaust emissions and other problems. The New Energy Research Center Energy Storage application technology research team found in the previous research, energy storage is suitable for temporary power supply and non-power distribution network operation scenarios. In 2012, the research team launched the development of a mobile energy storage vehicle.

“Temporary power supply and non-blackout scenarios require energy storage to move flexibly, which requires a carrier. At that time, we considered the combination of energy storage and vehicles as a key direction to promote the application of mobile energy storage on the ground as soon as possible,” said Tao Yibin, director of the Research Office of Energy Storage Application Technology at the new energy research center.

In 2013, the research team began to focus on the integrated design of energy storage system and vehicle chassis, integrated development of modular high-performance vehicle platform. In May 2014, the first generation of mobile energy storage power car R & D success. Since then, the research team has focused on the system's seamless off-grid switching, high-efficiency modular integration and other key technologies, a clear lightweight, high power density and modular research direction, and constantly upgrade the mobile energy storage vehicle.

By the end of the 2021 year, the Mobile Energy Storage vehicle had been upgraded to the third generation. The first generation of mobile energy storage power supply vehicle is in the form of on-board container with low integration and poor performance. The second generation mobile energy storage power supply vehicle enhances the off-grid switching technology and shortens the off-grid switching time. The third generation mobile energy storage vehicle has been upgraded to a highly integrated and versatile mobile energy storage system. The system can realize long-distance transportation, and has excellent performance such as seismic resistance, and can deal with different road conditions in the transportation.

The development of intelligent control unit helps the efficient utilization of new energy

New energy generation has intermittency and fluctuation. With the increasing proportion of power grid connected with new energy sources, the stability and reliability of power system are facing challenges. In order to further enhance the flexibility of the distribution network, enrich the application scenarios of the mobile energy storage power supply vehicle, and improve the operational efficiency, the research team carried out the debugging of the intelligent control unit of the mobile energy storage power supply vehicle, decoupling electricity production and consumption in terms of time, making the traditional“Rigid” power system with real-time balance“Flexible”, thus solving the problem of time-space mismatch between new energy generation and load electricity consumption, new energy consumption.

In 2018, the research team developed an intelligent control unit for a mobile energy storage vehicle. “The intelligent control unit can take into account the volatility of new energy generation and ensure the safe and stable operation of the new energy electric generator by charging the mobile energy storage vehicle under the new energy generation capacity and boundary conditions,” said Wang Deshun, deputy director of the Research Office of Energy Storage Application Technology at the new energy research centre.

The communication unit developed by the research team can realize the fast and accurate perception of the mobile energy storage electric vehicle by the distribution network, form the interactive mode with transparent information, and propose the operation control strategy for the mobile energy storage electric vehicle, including the Operation Mode and Power Command, form a flexible and efficient source-network charge-storage interaction mode. The mobile energy storage power supply vehicle can be completed in 10 milliseconds and off-grid seamless switching to achieve power supply“Zero flicker.”.

Mobile energy storage vehicles have been used in Longyan Gymnasium in Fujian province, Gutian Mountain Villa and Zhenjiang University Entrance Examination in Jiangsu province, as well as Yangzhou, Xinghua and Jiangyin, Jiangsu province and other places of temporary distribution transformer capacity increase, non-blackout distribution network operation site, accumulated experience.

Carrying fire early-warning system to achieve intelligent detection and early-warning

On April 13, Wang Deshun and his research team conducted a test of the on-board fire warning system on a 250kw-500kw mobile energy storage vehicle, simulating ambient temperatures. In the experiment, the system quickly detects that the temperature of the vehicle-mounted energy storage battery exceeds the safe temperature range and gives an alarm.

Thermal runaway warning and fire safety of batteries are the key to the safe application of energy storage. "The mobile energy storage PVS are based on battery technology. Early detection of potential hazards, early warning, and timely lowering of battery temperature are effective ways to prevent fire." Wang Deshun introduced.

The research team set up two detectors in combination with the vehicle-borne space division to form a fire early warning system. The detector can detect abnormal temperature and combustible gas at the same time, and realize intelligent detection and early warning of battery.

“The detector has four methods of judging the trend of gas concentration, the constant temperature, the temperature rise and the combined judgment of gas smoke temperature. It uses various methods to detect fire risks, such as fixed thresholds and sensor trend judgments,” said Yang Bo, deputy director of the New Energy Research Center. Four judgment methods play a combined role, the fire early warning system through a comprehensive processing of 1 -4 levels of alarm signal output to ensure the accuracy and timeliness of early warning.

The team also equipped the mobile energy storage vehicle with a dedicated 1,1,1,2,3,3,3-Heptafluoropropane extinguisher. 1,1,1,2,3,3,3-Heptafluoropropane (HFC-227) is a clean gas chemical fire-extinguishing agent which is mainly used for chemical fire-extinguishing and has physical fire-extinguishing functions, it is colorless, odorless, non-conductive, non-polluting, low density and small storage space. It can extinguish electric fire with lower concentration and will not cause damage to precision facilities.

Based on the research of Mobile Energy Storage Power Supply Vehicle, the research team took the lead in compiling 2 industry standards for optimal operation of distribution network, and the national standard“GB/T 36545-2018 technical requirements for mobile electrochemical energy storage systems” and the group standard“T/CEC 168-2018 testing procedures for mobile electrochemical energy storage systems”, by constructing and consolidating the standard system, the design, operation and test opinions of mobile energy storage power supply vehicle are put forward to promote the application of mobile energy storage power supply vehicle.