THE PROBLEM – HOW DO LITHIUM ION BATTERIES CATCH FIRE AND EXPLODE?

• A malfunctioning lithium ion battery may go into “thermal runaway,” as its internal temperature quickly exceeds its normal operating range and begins to burn
• Explosive gases, such as hydrogen, are then released as a byproduct of thermal runaway
• Nearby batteries will likely also enter thermal runaway, causing a dangerous chain reaction
• The greater number of malfunctioning batteries, the greater the risk of a catastrophic fire or explosion

FIKE’S SOLUTIONS

BESSs may be protected in various ways, which ultimately depend on:

• BESS’ proximity to urban areas, workers or other critical assets
• Concern of preserving the enclosed batteries
• Available budget
• Owner’s preferences (example: gaseous agents instead of water mist fire suppression)

Therefore, several “layers of protection” are available which range from the mitigation of a catastrophic fire to the prevention of a catastrophic fire.

LITHIUM ION BATTERY EXPLOSION PROTECTION

Explosion Vent Panels

To protect against the worst-case scenario of the shipping container exploding, Fike recommends that all BESSs are protected with explosion vent panels.

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 way 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.

LITHIUM ION BATTERY FIRE PROTECTION

Fire Suppression Systems

Fire suppression systems are often needed if the experiencing thermal runaway.

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) – Using ultra-fine water droplets that offer “three-dimensional” coverage at only 10 percent of the water output of a sprinkler system, Fike’s FM-approved DuraQuench pumped water mist system is an ideal fire suppressing agent for BESS protection. 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. Finally, water mist is safe to use for protecting and preserving electronics.

• Gaseous Agents (3M Novec™ 1230 Fire Protection Fluid™, FM-200) – 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 FM-200. These gaseous agents suppress incipient fires and are ideal for electrical Class C fires detected within a transformer, inverter or HVAC motor.

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 slowest to quickest to activate, include:

• Traditional Spot and 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.
• Thermal Imaging – Mounted outside to monitor multiple BESS units for increased temperatures from the HVAC exhaust vents. Thermal imaging provides an economic alternative to other methods which require detection within each BESS unit.
• Honeywell Analytics Industrial Gas Detection – Detects presence of off-gas within a BESS unit once it reaches a certain threshold.
• VESDA with Integrated Gas and Smoke Detection – Continuously samples the air for presence of gas or smoke particles within a BESS unit.
• Li-ion Tamer – Specifically engineered and designed for BESS fire protection; provides localized gas detection and reporting within individual lithium ion battery racks.