Electric Batteries: Which Components Are the Most Flammable?

When it comes to electric batteries, they are almost everywhere—even when we won't see them. They power everything from smartphones and laptops to electric vehicles and renewable energy systems. The more pieces of tech we launch and become reliant upon, the more we will use electric batteries, so our reliance isn't going to go down on them.

With our reliance growing, so too does the risk of battery-related fires. Understanding which components are most at risk of catching fire—and how to deal with them safely—is key to preventing accidents. And while prevention is always better than cure, knowing how to protect yourself with the right fire extinguisher is important, for example, using electrical fire extinguishers when you know it's an electrical fire. Alternatively, it's important to know when not to use water, as water can sometimes make things worse.

Below, we look more into electric batteries and which components are the most flammable.

The Electrolyte Fluid

The electrolyte inside a lithium-ion battery is one of its most critical yet most flammable components. It serves as the conductive medium that allows lithium ions to flow between the battery's positive (cathode) and negative (anode) terminals during charging and discharging. Typically, this electrolyte is a liquid or gel composed of organic solvents—such as ethylene carbonate or dimethyl carbonate—combined with lithium salts that enhance conductivity.

While this mixture is essential for battery performance, it is also highly volatile and flammable. When a battery is overcharged, punctured, exposed to high temperatures, or suffers internal damage, the electrolyte can vaporise and ignite. Once ignited, it burns at extremely high temperatures, producing intense flames and toxic gases such as carbon monoxide, hydrogen fluoride, and other harmful vapours.

These fires can spread rapidly, especially in confined spaces, and are notoriously difficult to extinguish due to the chemical reactions involved.

The Separator

A battery's separator is a thin yet vital plastic film designed to keep the anode and cathode apart, preventing direct contact between the two. While small in size, it plays one of the most critical roles in maintaining battery safety. If the separator fails—whether it melts, shrinks, or tears due to excessive heat, overcharging, or physical damage—the positive and negative electrodes can come into contact, resulting in a short circuit.

Once a short circuit occurs, the battery begins to heat rapidly, often triggering what's known as thermal runaway—a chain reaction where rising temperatures cause more heat to be generated internally. This process can quickly spiral out of control, leading to smoke or a fire.

The Cathode and Anode Materials

The cathode and anode are the heart of any battery—they're the components responsible for storing and releasing energy during each charge and discharge cycle. The anode (usually made of graphite) releases electrons, while the cathode (often composed of lithium compounds such as lithium cobalt oxide or lithium iron phosphate) accepts them, allowing power to flow through your device.

However, these materials can become highly unstable when damaged or exposed to extreme heat. During failure, the internal temperature of the battery can rise sharply, causing the cathode material to decompose and release oxygen. This oxygen acts as a fuel source, feeding nearby flames and turning what might have been a small spark into a full-blown fire. At the same time, the anode may also react with the electrolyte, generating additional heat and flammable gases.

The Battery Casing

While designed primarily for protection, the outer casing of a battery can also play a role in how a fire starts or spreads. The casing is meant to act as a barrier—shielding the delicate internal components from external impact, moisture, and heat. However, under extreme conditions, it can become a hazard in itself.

Many consumer batteries, such as those in smartphones, laptops, and e-bikes, use lightweight metal alloys or plastic shells to reduce weight and manufacturing costs. When exposed to intense heat, these materials can melt, warp, or rupture, exposing the inner components and releasing flammable gases. In some cases, the pressure that builds up inside the casing due to thermal runaway can cause it to burst or explode, scattering burning material across a wider area.

Electric batteries have revolutionised the way we live, powering everything from the smallest gadgets to the most advanced vehicles. However, their growing presence also means a greater need for awareness around the potential fire risks they pose. Understanding which components—such as the electrolyte, separator, electrodes, and casing—are most flammable is the first step toward using them safely.

Have you checked how your batteries are stored at home or at work? Do you know which fire extinguisher to use in an electrical emergency? And most importantly, are you confident you'd know what to do if a battery fire occurred? Let us know your thoughts in the comment box below. We look forward to hearing from you.