Battery Energy Storage Systems (BESSs) play a critical role in the transition from fossil fuels to renewable energy by helping meet the growing demand for reliable, yet decentralized power on a grid-scale. These systems collect surplus energy from solar and wind power sources and store them in battery banks so electricity can be discharged when needed, thus integrating intermittent renewable energy sources and helping to meet energy demand during peak hours and smooth out energy supply typically associated with renewables.

Advanced fire detection and prevention methods

Once a lithium-ion battery overheats in a BESS and the process of “thermal runaway” occurs, it can be nearly impossible to extinguish, potentially causing catastrophic damage and risking the lives of first responders called to put out the fire.

To best understand the complexities of these systems and reduce the risk, consider that lithium-ion cells are prone to failing if not kept within specific environmental conditions. When these conditions are compromised, so-called abuse factors can lead to thermal runaway. Awareness of these abuse factors can help operators prevent thermal runaway at its earliest stage.

Electrical abuse

This occurs when a battery exceeds voltage limits during charge or discharge and overheats. The simultaneous operation of these batteries poses the risk that any one of the battery cells could exceed voltage limits during charge or discharge and can cause overheating that triggers a potential fire event.

Thermal abuse

This is initiated when the operational temperature exceeds the limits of the battery. If caused by overcharging, the extra current triggers a chemical reaction that breaks down the battery’s organic liquid electrolytes and changes them from a liquid to a highly flammable gaseous state.

Mechanical abuse

This can be caused by physical or mechanical damage to the battery such as a crush, indentation or puncture from vibration or shock.

The best protection is prevention

It is common for mobile BESS units to be preconfigured with traditional heat and smoke detectors installed in interior spaces. These types of sensors are not up to the task of providing early warning of an impending fire because they are only sensitive enough to detect smoke after a fire has started and much too late to stop thermal runaway from igniting an entire bank of batteries. Furthermore, these systems cannot be serviced, monitored or maintained to ensure they are in basic working order due to unit design.

A holistic approach using advanced detection technologies and performance-based solutions combined with battery management systems can work together to establish layers of safety. Advanced detection innovations are the first line of defense, providing the very earliest possible intelligence about conditions inside the BESS. These early warning systems can be professionally tested, serviced and maintained to ensure peak performance and monitored at the fire alarm control panel. If an off-gas event occurs, sensors can be used to quickly notify facility operators to shut down the system or contact first responders to mitigate or stop the propagation or evolution of the event moving from one cell to multiple modules or units.

• Battery management systems monitor voltage, current and temperature to identify any battery abuse factors. While this is an important, initial layer, it should not be the only layer of protection.
• Temperature and humidity sensors measure the temperature of the air surrounding the sensor including ambient room temperature, shock/vibration/AC power quality and conditions.
• Thermal imaging cameras graphically illustrate the temperature of the objects and equipment the camera can see.
• Off-gas detection technologies can provide an alert in the initial stage of lithium-ion battery failure when venting of electrolyte solvent vapors begins and prior to thermal runaway.
• Very early warning smoke detection systems use ultra-sensitive sensors to provide early warning of an impending fire event, buying time to initiate an appropriate emergency response to prevent injury, property damage or business disruption.

Everon’s holistic approach to energy storage safety

Lithium-ion battery storage facilities are an important and growing part of the transition to a greener economy. Just as innovation is accelerating the evolving renewable energy industry, advanced fire prevention and life safety technologies like off-gas detection, very early warning smoke detection and thermal imaging camera systems designed by a trusted fire protection engineer or a life safety professional, combined with advanced alarm monitoring, can help ensure battery storage facilities are operating at the highest levels of safety.

Everon’s advanced detection technologies and performance-based solutions for BESSs work together to establish layers of safety and fire prevention—beyond the prescriptive code minimum requirements. Connect with an expert today to learn how we can help you build a robust first line of defense with innovative solutions to help protect your facilities, building occupants, and emergency responders.