How Do Lithium Ion Batteries Catch Fire & Explode?

In April 2019, seven Arizona firefighters were hurt and one was killed from an explosion occurring within a BESS shipping container. When the door to the container was opened by the investigating firefighters, oxygen was introduced into a dangerous mixture of explosive gases and heat, and sadly resulted in a devastating explosion.

lithium ion battery malfunction

Battery Malfunctions

A malfunctioning lithium ion battery may go into “thermal runaway,” as its internal temperature quickly exceeds its normal operating range and begins to burn.

lithium battery off-gassing from thermal runaway

Off-gas Released

Explosive gases such as hydrogen are released as a byproduct of thermal runaway.

thermal runaway in battery energy storage systems

Affects Nearby Batteries

Nearby batteries will likely also enter thermal runaway, causing a dangerous chain reaction.

thermal runaway consumes entire rack

Consumes Entire Rack

The greater the number of malfunctioning batteries, the greater the risk of a catastrophic fire or explosion.

Battery energy storage systems may be protected from fires in various ways, which ultimately depend on:

The unit’s proximity to urban areas, workers or other critical assets.

Concerns of preserving the enclosed batteries.

Available budget.

Owner’s preferences, such as using chemical agents instead of water-based solutions.

Fire Protection Recommendations For Non-Remote BESS

Fike Blue - lithium ion battery protection

Li-Ion Tamer is the earliest and most reliable method of detecting the off-gas from a malfunctioning battery. Sensors are applied directly onto battery racks to identify the gas as early as possible.


A cost-effective alternative to Li-Ion Tamer, Sensepoint XCD is an industrial gas detector installed on the ceiling of the storage unit. It detects the same off-gas as Li-Ion Tamer but lacks the sensors placed directly within the racks.


In the battery rack area, a water mist system removes combustible particulates and provides prolonged cooling to inhibit the transfer of heat from one cell to another. Fike DuraQuench connects to the water main or a reservoir for unlimited discharge.


In the control room area, clean agents such as 3M™ Novec™ 1230 Fire Protection Fluid or FK-5-1-12 are used to absorb large amounts of heat and extinguish fire by cooling the combustion zone.


A fire panel connected to the unit’s BMS activates ventilation to flush out explosive gases.

How the Problem of Thermal Runaway in Energy Storage Systems has been Solved

Thermal runaway in lithium batteries results in an uncontrollable rise in temperature and propagation of extreme fire hazards within a battery energy storage system (BESS).

It was once thought to be impossible to stop a cascading thermal runaway event, until now with Fike Blue™.

Fire Protection Recommendations For Remote BESS


Spot detectors are installed to monitor the smoke of a burning lithium ion battery. The connected fire panel identifies the hazard, may open ventilation to flush explosive gases, and alerts the closest fire department.


A pre-engineered and self-contained water mist system for locations without a water supply, Fike Micromist removes combustible particulates and prohibits the transfer of heat from one cell to another. Alternatively, sprinkler systems may control the fire until fire safety personnel arrive.


For BESS units without fire suppression systems and active ventilation systems, explosion vent panels should be installed on the roofs so if a deflagration were to occur, the pressure will force the vents open and safely relieve the pressure and flames upward into the atmosphere.

Ready To Learn More?

Fire Suppression Systems

When a malfunctioning battery is detected, either through gas, smoke or heat detection, the connected fire panel may release one of two recommended fire suppression systems:

Water Mist (DuraQuench®) 

Water mist both clears the air of combustible gas and particulates and provides a prolonged cooling effect to help inhibit the transfer of heat from one cell to another. Safe for electronics, ultra-fine water mist droplets offer “three-dimensional” coverage, ensuring it penetrates deep-seated fires unreachable by sprinkler droplets.

Fike’s FM-approved DuraQuench pumped water mist system is an ideal fire suppressing agent for BESS protection as it provides unlimited discharge drawn from the local water supply or a reservoir. Alternatively, Fike Micromist is a self-contained and pre-engineered water mist system ideal for remote locations lacking a water supply.

Chemical Agents

(3M™ Novec™ 1230 Fire Protection Fluid and FK-5-1-12)

For those who prefer to use clean agent suppression instead of water-based suppression, Fike offers two of the most reliable solutions in 3M Novec 1230 and FK-5-1-12, which are ideal for electrical Class C fires. Chemical agents are also often preferred on the control room side of the BESS where servers, computers and other electronics are stored.

Fire Detection Systems

One of the most impactful decisions for limiting fire damage and preserving the BESS is the chosen method of detection. Various detection options are available to identify the stages of thermal runaway: temperature increase, off-gases, smoke and flame.

The earlier a malfunctioning battery is detected, the sooner fire suppression systems may activate. However, if suppression systems are not installed, detection is still essential as it can activate HVAC vents to flush out off-gases, sound alarms and notify emergency responders.

Detection options from fastest to slowest detection include:

Distributed Temperature Sensing Cable

Measures a complete temperature profile in real time, and therefore can detect the precise location of a malfunctioning battery far before it reaches the thermal runaway.


Li-ion Tamer

Specifically engineered and designed for BESS fire protection; provides localized gas detection and reporting within individual lithium ion battery racks.


VESDA With Integrated Gas & Smoke Detection

Continuously samples the air for presence of gas or smoke particles within a BESS unit.


Honeywell Analytics Industrial Gas Detection

Detects presence of off-gas within a BESS unit once it reaches a certain threshold.


Traditional Spot & Heat Detection

Placed inside the BESS enclosure to detect presence of smoke or heat. However, by the time traditional detection activates, thermal runaway of a lithium ion battery is well underway. This method is not recommended for those who hope to suppress the fire and preserve the BESS.

Explosion Venting Systems

For BESS units that lack active ventilation systems, Fike recommends they are protected with explosion vent panels to protect against the worst-case scenario.

If a deflagration occurs within a BESS container, the explosion vents installed on the top of the enclosure will burst at a predefined low burst pressure, releasing the pressure and flames in a controlled manner and thereby preventing an uncontrolled rupture of the vessel. Explosion vents are considered “passive” solutions, meaning they activate from the pressure itself and require no electronic intervention.

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