Exposing a battery to fire is extremely hazardous. Such an action can trigger a rapid and dangerous chain of events within the battery’s structure.
The Science Behind the Danger
Placing a battery in fire subjects it to extreme external heat, which dramatically increases its internal temperature. This elevated temperature initiates chemical reactions, particularly the decomposition of the battery’s electrolyte. The electrolyte, often an organic compound, breaks down, releasing flammable gases and causing a rapid increase in internal pressure within the sealed casing.
This process can lead to “thermal runaway,” a self-perpetuating chain reaction. As the temperature rises, components like the solid electrolyte interphase (SEI) film on the anode can decompose, releasing more heat. Further increases in temperature cause the cathode material to decompose, releasing oxygen, which fuels the fire. This internal heating accelerates further chemical reactions, leading to an uncontrollable cycle where temperatures can escalate rapidly, ultimately resulting in fire or explosion.
Immediate Hazards and Risks
The uncontrolled chemical reactions inside a battery exposed to fire pose several severe dangers. The rapid buildup of internal pressure can cause the battery casing to rupture or explode, turning components into dangerous projectiles. These explosions can inflict severe physical injury and cause significant property damage.
Flammable organic electrolytes present in many batteries can ignite, resulting in intense fires that are difficult to extinguish. These fires can spread quickly and generate their own oxygen, especially in lithium-ion batteries, making them self-sustaining. Burning batteries also release toxic and corrosive fumes, such as hydrogen fluoride, which can cause chemical burns and severe respiratory issues upon inhalation.
How Different Battery Chemistries React
The specific reaction of a battery to fire can vary significantly based on its chemical composition. While the general principle of thermal runaway applies, the severity and type of hazards differ. Lithium-ion batteries, common in portable electronics and electric vehicles, are particularly known for volatile thermal runaway due to their high energy density and flammable organic electrolytes. When subjected to fire, they can experience rapid temperature spikes and release flammable and toxic gases, leading to intense fires and potential explosions.
Alkaline and nickel-cadmium (NiCad) batteries, often found in household devices, typically react less violently than lithium-ion cells when exposed to fire. They can still rupture due to pressure buildup and release corrosive chemicals, but the risk of explosive thermal runaway and intense fire is generally lower. Lead-acid batteries, commonly used in vehicles, contain sulfuric acid and lead. In a fire, they can release highly corrosive sulfuric acid mist and generate explosive hydrogen gas, posing risks of chemical burns and further explosions.
Safety Protocols and Emergency Actions
If a battery catches fire, immediate and decisive action is important to minimize harm. The first step is always to evacuate the area and ensure everyone is at a safe distance from the burning battery. Emergency services, such as the fire department, should be contacted immediately, providing specific information about the battery type if known. Attempting to extinguish a battery fire, especially a lithium-ion battery fire, with water can be ineffective or even worsen the situation, as some battery materials react with water. For small battery fires, a Class D extinguisher (for metal fires) or a large amount of sand may be appropriate.
Preventing battery fires involves proper handling, storage, and disposal. Store batteries in a cool, dry place away from direct sunlight, extreme temperatures, and flammable materials. Avoid physical damage, such as punctures or crushing, and use only chargers designed for the specific battery type. Never dispose of batteries in regular trash or fires, as this is a common cause of incidents. Instead, utilize certified battery recycling programs or household hazardous waste facilities for safe disposal.