Battery Energy Storage Systems (BESS) installations on board ships have been increasing in number and installed power as the battery technology also develops.
According to the Alternative Fuels Insight platform, there are more than 800 battery ships in operation, a figure that has more than tripled in the past five years. The main risks associated with this type of battery are fire and explosion due to thermal runaway and off-gas generation.
At the moment, there is no regulatory instrument at international level on the safety aspects of using batteries in ships. Lithium-ion batteries are currently the most popular choice for ship operators. EMSA has drawn-up a nonmandatory Guidance to guide industry about the essential safety requirements for battery energy storage systems on board of ships
Types of BESS generated fires due to thermal runaway
#1 Electrical fire – overcharging/discharging or low temperature causing dendritic growth, lithium plating causing short circuits (leading to thermal runaway and fire)
#2 Thermal fire – over temperature causing the electrolyte decomposition or melting separator (leading to thermal runaway and fire).
#3 Mechanical fire – events that can lead to penetration of the enclosure of the battery/cell (such as drop of objects, ship’s collision, grounding, maintenance errors) causing short circuits, (leading to thermal runaway and fire)
#4 Internal short circuit – failure of the separator due manufacturing fault or any of the above conditions
10 key measures to consider for BSEE fire safety
1. Detectors should be installed in the room or space at least in the air extraction ducts
2. Detectors should be capable of off- gas, heat and smoke detection
3. The components of the detection system installed inside the battery space should be certified for use in explosive atmospheres
4. Ambient temperature monitoring with alarms should be available from a manned location
5. The temperature increase rate beyond which an alarm should be initiated, to be defined
6. Detection system should interface with the Battery Management System for shutdown operation and isolation of the battery pack/module/rack
7. Detection system should be independent from the BESS built-in system
8. Controls should be provided to de-energize electrical equipment upon gas detection
9. Containerized BESS should be provided with a detection system that will communicate with the ship’s system
10. High/ Low ambient temperature and other abnormal conditions should initiate an alarm at a manned control station
