Why is it difficult to extinguish lithium battery fires using conventional methods?

Figure 1:lithium battery fires

Lithium ion battery is an energetic component mainly composed of positive electrode, negative electrode, electrolyte, and separator.

Figure2: Typical Li-ion battery composition

The safety hazards of lithium batteries mainly come from the combustible organic electrolyte inside. When the battery is damaged, overheated, or short circuited internally, it can expose the electrolyte to the air and easily self ignite.

When lithium-ion batteries are overcharged or charged with unsuitable chargers, the lithium ions in the lithium-ion battery cannot be properly embedded in the negative electrode, and the lithium ions precipitate as metallic lithium, producing dendritic lithium like nails that pierce the insulating membrane between the positive and negative electrodes. After the positive and negative electrodes are short circuited, excessive heat accumulation occurs inside the battery, triggering a chain reaction that leads to combustion and explosion.

When solar lithium batteries catch fire, dry powder fire extinguishers or sand cannot stop it from continuing to burn or explode. The fire will only be extinguished after the thermal runaway reaction is over. The so-called "thermal runaway" refers to a series of self accelerating chemical reactions of various materials in lithium batteries at high temperatures, which make the thermal runaway irreversible.

The only effective method is to have a large amount of water. A large amount of water not only extinguishes open flames, but also soaks battery cells to cool them down and reduce their ability to continue reacting. This safety concern is particularly important when dealing with stackable lithium batteries, as their compact arrangement can potentially increase the risk of thermal runaway spreading between lithium ion battery cells.

So when a lithium battery catches fire,how to extinguish battery fire?

Dry powder fire extinguishers can only extinguish surrounding flames,but it is unable to effectively prevent thermal runaway of lithium batteries.

Water or water-based fire extinguishers is the first choice for emergency response to lithium battery fires.

Figure3: use water to extinguish battery fire

Precautions for extinguishing lithium battery fires

1) Disconnect or remove the external power supply from the fire equipment.

2) Immediately and continuously immerse electronic devices in water or other non flammable liquids to reduce the temperature of lithium battery cells and prevent adjacent battery cells from catching fire.

3)If the device was previously connected to a power outlet, unplug all other power outlets until the system is confirmed to be fault free.

4) Do not attempt to move burning or smoking electronic devices with bare hands or other parts of your body to prevent serious personal injury. Under the premise of ensuring one's own safety, fire hooks can be used to tow away combustion electronic devices.

5) Do not cover with objects or attempt to lower the temperature with ice cubes. This method of isolating equipment will result in the inability of the device's heat to dissipate in a short period of time, and instead increase the danger.

Be careful!

Lithium batteries will explode instantly when they catch fire.

Toxic smoke spreads rapidly.

If trapped in it, self rescue is difficult.

Very likely to die from suffocation when encountering a lithium battery fire.

Be sure to evacuate personnel immediately and call the emergency fire telephone number.