Lithium-Ion Battery Fire: What Causes It & How to Control It

• Lithium-ion batteries are rechargeable, lightweight, long-lasting and highly efficient.
• The chemical makeup of lithium-ion batteries makes them susceptible to overheating if not managed properly.
• Lithium-ion battery fires are typically caused by thermal runaway, where internal temperatures rise uncontrollably.
• Lithium-ion battery fires can be prevented through careful handling, proper storage and regular monitoring.
• Fire extinguishers explicitly designed for lithium-ion battery fires are the best to use. Class D or Class B (carbon dioxide) can also be used but are less effective.

Lithium-ion batteries, also known as Li-ion batteries, are rechargeable batteries that store energy by moving lithium ions between two electrodes.

These batteries are known for their high energy density, lightweight design and long lifespan.

Li-ion batteries are found in:

• Consumer Electronics: Smartphones, laptops, tablets and cameras.
• Electric Vehicles (EVs): Cars, bikes and scooters.
• Renewable Energy Systems: Solar battery storage units.
• Industrial Equipment: Power tools, drones and robotics.
• Medical Devices: Portable monitors and ventilators.
• Household Appliances: Cordless vacuums and electric toothbrushes.

The chemical composition that makes Li-ion batteries so efficient also makes them susceptible to overheating if mishandled.

Thermal runaway, where the internal temperatures of the batteries rise uncontrollably, is the leading cause of battery failure, leading to fires.

This can occur due to:

• Physical Damage: Dropping or puncturing a battery can damage its internal structure.
• Overcharging: Charging beyond the battery’s limit can cause overheating.
• Manufacturing Defects: Flawed components or assembly errors increase fire risks.
• External Heat Exposure: High ambient temperatures or heat sources can trigger a fire.
• Improper Disposal: Crushing or mishandling discarded batteries can cause fires, especially in waste processing environments.

Once thermal runaway begins, the battery’s temperature rises rapidly, often exceeding 700°C to 1000°C. This extreme heat causes the battery’s cells to break down, releasing flammable gases. If the battery is in an enclosed space, these gases can form a flammable vapour cloud explosion (VCE), further increasing fire risks.

As the heat builds, the battery cells rupture and ignite. The fire spreads quickly as more cells decompose and vent gases, creating a chain reaction.

Unlike other types of fires, which typically burn at a steady rate, lithium-ion battery fires escalate much faster and are significantly more difficult to control.

Large batteries, like those in electric vehicles, may reignite hours or even days later, even after they have been cooled.

Fortunately, Li-ion battery failures are relatively rare. But numbers are rising as Li-ion technology becomes more widely adopted.

According to the latest UK statistics:

• Battery fires in bin lorries and waste sites soared to 1,200 in 2023, up 71% from 700 in 2022.
• Fires involving e-bikes and e-scooters reached 338 incidents in 2023.
• An estimated 201 fires per year are attributed to lithium-ion batteries discarded in domestic and business waste.

The Regulatory Reform (Fire Safety) Order 2005 outlines fire safety legislation for non-domestic premises. Under this law, the responsible person ­­– typically the owner, employer or occupier – is accountable for managing fire safety on their premises. Their primary duty is to have a fire risk assessment carried out by a competent person. This assessment should cover the entire premises and all potential fire risks, including those posed by lithium-ion batteries.

While there are no UK fire safety standards specifically for lithium-ion batteries, there are standards for overall battery safety and performance, including:

• Outlines safety requirements and testing procedures for lithium-ion batteries in portable electronic devices such as mobile phones, laptops and tablets.
• Addresses safety concerns related to battery performance, including overcharging, over-discharging, short-circuiting and thermal runaway.

• Focuses on the safety of lithium battery cells.
• Includes requirements for preventing electrical, chemical and thermal hazards during normal and abusive conditions.

• Primarily aims at energy storage systems (including batteries).
• Covers safety evaluation for systems that incorporate lithium-ion batteries, particularly large-scale battery setups.

Controlling a lithium-ion battery fire requires a specific approach due to the unique chemical reactions involved. Here’s how such fires can be managed:

1. Evacuate the Area: Immediately evacuate everyone from the area where the battery fire has occurred.
2. Use Fire Extinguishers: Fire extinguishers explicitly designed for lithium-ion battery fires are the best to use. Class D or Class B (carbon dioxide) can also be used but are less effective.
3. Isolate the Battery: If safe, move the device or battery to a non-flammable surface.
4. Cool the Area: Use sand or other non-flammable substances to smother flames and absorb heat.
5. Call Professionals: Notify emergency services immediately, especially for large fires.

Preventing lithium-ion battery fires requires careful handling, proper storage and regular monitoring. Here are essential measures to reduce the risk:

• Use Approved Equipment: Only use batteries, devices and chargers from trusted manufacturers to ensure quality and safety.
• Inspect Regularly: Frequently check batteries for damage, such as swelling or cracks. Avoid using damaged or defective batteries.
• Store Safely: Keep batteries in dry, cool and well-ventilated areas, away from high humidity. Ensure storage spaces are free from flammable materials, sharp objects and conductive surfaces.
• Charge Responsibly: Train staff to manage battery charging properly. Remove batteries from chargers once charging is complete, and never leave them charging unattended.
• Dispose Properly: Dispose of lithium-ion batteries at certified recycling or disposal facilities. Never throw batteries in general waste or recycling bins, as improper disposal can cause fires or environmental harm.
• Train Staff: Provide training on emergency procedures and handling damaged batteries. Ensure staff prioritise their safety when responding to battery-related fires.
• Use Protective Storage: Store unused batteries in fireproof containers such as metal cabinets or specialised safety bags.
• Limit Storage Size: Limit the number of lithium-ion batteries stored together, as one case of thermal runaway can set off a chain reaction.
• Manage Battery Charge Levels: Lower the risk of thermal runaway by reducing the state of charge (SOC) for batteries not in use or during extended storage.

Lithium-ion battery fires can pose serious safety risks, but many of these incidents can be prevented with proper awareness and training. Understanding the risks associated with these batteries and learning the best practices for their use, storage and disposal is essential in reducing fire hazards.

Our online Lithium-Ion Battery Safety course explains how to use, handle and dispose of these batteries correctly. The IIRSM-approved course also looks at the potential consequences of lithium-ion battery use and necessary control measures to prevent fires.