Lithium battery energy storage early warning system -Lithium - Ion Battery Equipment
In recent years, various electrochemical energy storage projects have sprung up like mushrooms after a spring rain, covering various fields such as the user side, the grid side, the power generation side, new energy grid connection and microgrid. There have been many fire accidents in lithium battery energy storage power stations recently at home and abroad. On July 2, 2018, a major fire accident occurred in the ESS energy storage equipment in a wind power park in South Korea, causing a 706m2 battery building and more than 3,500 lithium batteries to be burned. It can be seen that once a fire accident occurs, it will cause serious consequences. At this time, it is particularly important to identify the characteristic parameters of lithium battery thermal accidents, early warning of thermal runaway, safety linkage and fire protection.
The safety of lithium battery energy storage power stations is a major issue that should keep the alarm bells ringing. With the research and development of new materials for lithium batteries, the innovation of battery manufacturing technology, and the participation of many scientific research institutions and companies, the performance of lithium batteries is increasing day by day, and the safety performance of single cells has also been greatly improved. However, due to the larger single battery capacity of the large-scale energy storage system, the larger number of battery cluster cells, the larger number of battery clusters in parallel, the larger battery stack current, the deeper battery cluster charge and discharge depth, and the battery cluster operation consistency and life requirements. It is more strict, and local thermal runaway is easy to occur in the process of use, and there is a huge safety hazard.
This paper studies the characteristics and parameters of lithium battery thermal runaway, composite thermal runaway fire detector, multi-level early warning mechanism and safety linkage strategy.
1 Identification of thermal runaway characteristics
1.1 Identification of thermal runaway and thermal diffusion characteristics
The identification of battery thermal runaway and thermal diffusion characteristics is the basis for the research on fire early warning system of lithium-ion energy storage power station. Some teams at home and abroad have carried out research on the identification methods of thermal runaway and thermal expansion in the early stage, mainly including the following methods: ① The battery surface temperature, voltage, current and discharge rate parameters obtained by BMS are used as the discriminating conditions; ② Based on Detection method of pressure strain of battery module; ③ Thermal runaway detection based on change of internal resistance; ④ Thermal runaway test caused by battery overcharge and heating, collect gas, and analyze gas composition and content by chromatographic analysis to determine thermal runaway method of early warning.