Standards to address the safety of lithium-ion batteries are evolving and have adapted to address the hazards associated with thermal runaway leading to fires and explosions. Manufacturers are working on meeting various international testing standards to ensure the safety and compliance of batteries, cells, modules and packs. However, there is always a risk of a battery failure or an incident impacting the integrity of the battery, which can lead to thermal runaway, with accumulation of gases, overheating, flaming or explosion.
Regulations are being developed and updated to keep up with the various risks associated with lithium-ion battery applications in the transportation and logistics sectors. In addition to powering vehicles and boats, batteries are used in energy storage systems as well as vehicles in warehouses and transit centers and on cargo ships. The risks and hazards vary. Factors that come into play include battery chemistry, power rating and capacity, and state of charge (SOC). The size, location and construction of the enclosures where they are located must also be considered as well as the nearby presence of other combustibles, such as batteries, equipment, vehicles or other property.
Mitigation strategies start with the battery management system, video monitoring, gas detection, linear heat detection, ventilation and suppression. Water-based suppression systems with high density coverage are designed to contain lithium-ion battery fires to a specific area and provide cooling of the radiated heat and exposed combustibles. However, they will not stop the thermal degradation of the combustible electrolyte in the battery. In most cases, automatic suppression needs to be supplemented by firefighting teams entering a space with sufficient hose lines and water supply to safely manage the incident.
A catastrophic failure occurs when mitigation measures are improperly designed, insufficient or impaired. Emergency response procedures are also critical hazard mitigation measures, and implementation of the right measures, may contribute to reducing the risk of catastrophic event occurrence. As part of these procedures, accessibility for firefighters trained to deal with these kinds of incidents, and availability of equipment and facilities to isolate the vehicle, containers, or equipment with the failed battery are critical to reducing the potential for fire and explosion propagation.
It is also essential to pro-actively monitor and supervise the condition of batteries. This includes having detailed procedures for handling, removing, and relocating a defective or impacted battery and the equipment it powers. While low-battery SOCs below 30% are associated with a lower probability for flaming thermal runaway events, the presence of combustible electrolyte within the battery still carries the potential for release of flammable gases. To handle such risks, consideration must be given to implementing mitigation measures and training in appropriate emergency procedures.
Jensen Hughes fire and process safety experts regularly work with clients to review battery hazards, assess risks associated with their specific applications, and recommend and develop mitigation strategies in the transportation sector.