Why is BESS safety a top priority?
BESS (Battery Storage System) systems use lithium-ion batteries or other battery technologies to store energy, providing high energy density but also pose potential risks such as fire and explosion, thermal runaway if the management system is not effective.
As reported by NFPA (National Fire Protection Association) 855 2023, more 80% of major failures involve energy storage systems worldwide are associated with heat waves and inadequate safety management.
NFPA recommends minimum installation distances between BESS units, and requires a flammable gas detection system in each container – a factor that many ESS implementers have not fully implemented. (According to “NFPA 855: “Standard for the Installation of Stationary Energy Storage Systems”).
Current Regulatory Framework and Safety Standards
UL 9540 & UL 9540A (USA)
- UL 9540 is the overall safety evaluation standard for BESS systems.
- UL 9540A focuses on testing thermal runaway propagation (heat transfer from battery cell to battery cell) to determine the possibility of fire propagation.
- UL9540A is not just a one-time test, but many major manufacturers perform it periodically on batches to demonstrate consistency – this is the new trend.
IEC 62933 (International)
- Sets guidelines for the design, operation and testing of electrical energy storage systems.
NFPA 855 (USA)
- Standards for the installation of fixed BESS systems, including regulations on spacing, fire protection, and flammable gas monitoring.
Container Safety Convention (CSC)
- Required for international export BESS containers, certified for strength, stackability, and safe transportation.
Technical solutions to prevent heat transfer
This is the part that engineers are most concerned about but often not widely shared. Thermal Runaway is a phenomenon where one battery cell overheats and triggers a chain reaction that affects neighboring cells.
Some proven technical solutions:
- Module design with heat-resistant partition: Many manufacturers use insulating ceramic materials or heat-resistant polymers to separate the battery cells.
- Advanced HVAC & BMS systems: Monitors each battery cell and adjusts temperature evenly, reducing the risk of hot spots.
- Automatic venting: Containers have pressure relief valves to release gas before pressure builds up.
According to the report DNV (Det Norske Veritas) Energy Storage Safety 2024, systems with integrated fire barriers between battery modules reduce up to 70% chance of thermal runaway transmission【Source: DNV Energy Storage Safety 2024】.
Building a safe future for BESS
BESS safety is not limited to current standards but also needs to be long term strategy:
- Standardize operational data: record and analyze temperature and current data to improve BMS.
- Cooperate with local fire authorities: Train rescuers to understand how to handle ESS.
- Research into next-generation batteries is less risky: Solid-state batteries are being seen as the future to reduce the risk of thermal runaway [Unverified – no official reports of large-scale commercialization].
- Many international companies have begun to apply the “fire department familiarization” model – inviting local firefighters to visit BESS containers to familiarize themselves before operating.
Ensuring the safety of BESS systems is no longer an option but a mandatory requirement to protect assets, people and brand reputation. International standards such as UL9540, IEC 62933, NFPA 855 and CSC certification help BESS container manufacturers improve reliability and exportability. By applying less common but effective technical solutions such as thermal partitions, venting, advanced HVAC/BMS systems, the energy storage industry can absolutely move towards a safer, more sustainable and reliable future.
