What is thermal runaway?

In a world that’s always on the go, lithium-ion batteries are the silent energy source keeping our devices and lives running smoothly. But despite their widespread use, there is still a fire risk associated with these batteries: thermal runaway. But what is thermal runaway, and how can it be prevented?

Here, we explain what exactly this process is, what causes thermal runaway in lithium-ion batteries, and how to put fire safety measures in place to mitigate the chances of it happening.

What is a thermal runaway?

To understand how to stop thermal runaway happening, it’s important to know what it is:

• Put simply, thermal runaway is an uncontrollable, self-heating state that is only stoppable through the removal of chemicals or heat. 
• Thermal runaway occurs when the battery temperature reaches 60°C or more, at which point large amounts of toxic and flammable gases are released and a sharp rise in temperature occurs. 
• Very soon after, the gases burst the battery and almost always ignite. This fire then rapidly propagates across all the cells in the battery, causing thermal runaway in otherwise undamaged cells.
• The explosive nature of the molten metal and the degree of collateral fires it causes is huge, causing peripheral fires to spread to surrounding areas.

What causes thermal runaway in lithium-ion batteries?

Since lithium-ion batteries are more prone to overheating than lithium batteries, there are various ways thermal runaway can be triggered. These include:

• Overcharging lithium-ion devices.
• Exposing lithium-ion devices to extreme temperatures.
• Physical damage to a lithium-ion-containing product.
• Products with manufacturing defects or low-quality components.
• Storing lithium-ion batteries incorrectly.
• Disposing of lithium-ion batteries improperly.

How to avoid thermal runaway

Since there are various ways this self-heating state can occur, it’s important to avoid any chance of damage, overheating, or incorrect use. Knowing how to prevent thermal runaway in batteries containing lithium-ion is important, and those responsible for fire safety should follow these precautionary steps:

Purchase high-quality products

To reduce the risk of thermal runaway in lithium-ion batteries, a good start is to choose devices or batteries from reputable brands and suppliers. Check the company’s safety standards and see if products have undergone rigorous testing in the manufacturer’s guide before buying, to help lower the chances of a malfunction.

Avoid overcharging

Overcharging devices creates heat, which can lead to thermal runaway. To prevent this, always follow the manufacturer’s charging recommendations. Thankfully, many modern devices have built-in safety features that prevent overcharging, but it’s still essential that devices are unplugged once they’ve reached a full charge. 

Don’t expose devices to extreme temperatures

Since lithium-ion batteries are sensitive to temperature fluctuations, extreme heat or cold can lead to battery malfunctions. Knowing how to avoid thermal runaway can be as simple as keeping devices out of direct sunlight, or hot cars in summer. Likewise, using your device in extremely cold temperatures can reduce battery life and cause issues.

Physically protect devices

Since lithium-ion batteries can leak, avoid dropping, puncturing, or crushing devices that contain them to prevent thermal runaway occurring. Even minor damage to the battery casing can lead to leakage or fires, but using protective cases or covers can minimise the risk of this physical damage.

Inspect batteries regularly

Perform routine inspections of lithium-ion devices to check for any signs of wear and tear. Swollen batteries, cracks, or other abnormalities are all warning signs. If there are signs of damage, consult the manufacturer or a professional technician for advice on replacement or repair.

Store and dispose of batteries responsibly

When storing spare lithium-ion batteries or devices, keep them in a cool, dry place, away from direct sunlight and extreme temperatures, and in a manner that prevents physical damage or short circuits. Always dispose of lithium-ion batteries at a recycling facility and never throw them in the bin or incinerate them, as this can lead to environmental contamination and potential safety hazards.

Be prepared for emergencies

Despite knowing how to avoid thermal runaway, accidents can still happen. Ensuring the appropriate fire safety equipment is installed and in good working order is crucial. In case of a lithium-ion battery fire, evacuate the area safely, and use a fire extinguisher capable of putting out lithium-ion fires as your means of escape. 

The evolutionary way to extinguish thermal runaway

The only way to stop the thermal runaway – as well as its quick spread, toxic fumes, and explosive nature – is to cool the battery cells to break the chain reaction of other battery cells overheating. 

CommanderEDGE LFX lithium-ion fire extinguisher breaks the chain reaction by drawing out the heat. It’s endothermic. The foam-like texture means that LFX sticks to the surface of a battery a lot longer than a normal liquid would, hugely increasing its ability to draw heat out of the batteries. The heat also causes the chemicals in the agent to crystallise further drawing heat out of the batteries. 

So, how does LFX work?

• It’s an effective water-based fire extinguishing agent that is excellent at putting out flames.
• It has market-leading heat-absorbing properties that break down the chain reaction in thermal runaway and prevent other cells from heating. It effectively cools cells that have already ignited as well as those that are in thermal runaway that have not yet exploded.
• In addition to tackling lithium-ion battery fires, LFX also protects from secondary A-class fires and this allows the extinguisher to quickly tackle ‘peripheral’ fires that have been caused by the exploding batteries.

As a result, thermal runaway can be effectively halted, extinguishing the failed cells within the battery, and then stopping other cells from exploding. 

Preventing lithium-ion battery fires requires a combination of understanding how thermal runaway starts and taking proper precautions. By following these key points, the chances of encountering a lithium-ion battery-related fire can be reduced. 

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