Why Lithium Batteries Catch Fire

Lithium battery that has caught on fire.

Daniel Steger/OpenPhoto/CC BY 3.0

Lithium batteries are compact, lightweight batteries that hold considerable charge and fare well under constant discharge-recharge conditions. The batteries are found everywhere — in laptop computers, cameras, cell phones, and electric cars. Although accidents are rare, those that do occur may be spectacular, resulting in an explosion or fire. In order to understand why these batteries catch fire and how to minimize the risk of an accident, it helps to understand how the batteries function.

How Lithium Batteries Work

A lithium battery consists of two electrodes separated by an electrolyte. Typically, the batteries transfer electrical charge from a lithium metal cathode through an electrolyte consisting of an organic solvent containing lithium salts over to a carbon anode. The specifics depend on the battery, but lithium-ion batteries usually contain a metal coil and a flammable lithium-ion fluid. Tiny metal fragments float in the liquid. The contents of the battery are under pressure, so if a metal fragment punctures a partition that keeps the components separate or the battery is punctured, the lithium reacts with water in the air vigorously, generating high heat and sometimes producing a fire.

Why Lithium Batteries Catch Fire or Explode

Lithium batteries are made to deliver high output with minimal weight. Battery components are designed to be lightweight, which translates into thin partitions between cells and a thin outer covering. The partitions or coating are fairly fragile, so they can be punctured. If the battery is damaged, a short occurs. This spark can ignite the highly reactive lithium.

Another possibility is that the battery can heat to the point of thermal runaway. Here, the heat of the contents exerts pressure on the battery, potentially producing an explosion.

Minimize the Risk of Lithium Battery Fire

The risk of fire or explosion increases if the battery is exposed to hot conditions or the battery or internal component is compromised. You can lessen the risk of an accident in several ways:

  • Avoid storing at high temperatures. Don't keep batteries in hot vehicles. Don't allow a blanket to cover your laptop. Don't keep your cell phone in a warm pocket. You get the idea.
  • Avoid keeping all your items containing lithium-ion batteries together. When you travel, especially on a plane, you'll have all your electronic items in one bag. This is unavoidable because the batteries have to be in your carry-on but usually, you can keep some space between battery-containing items. Although having lithium-ion batteries in close proximity does not increase the risk of a fire, if there is an accident, the other batteries can catch fire and make the situation worse.
  • Avoid overcharging your batteries. These batteries do not suffer "memory effect" as badly as other types of rechargeable batteries, so they can be discharged and recharged many times nearly back to their original charge. However, they do not fare well if they are completely drained before recharging or are over-charged. Car chargers are notorious for overcharging batteries. Using any charger other than the one intended for the battery can increase the risk of damage.
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Your Citation
Helmenstine, Anne Marie, Ph.D. "Why Lithium Batteries Catch Fire." ThoughtCo, Apr. 5, 2023, thoughtco.com/why-lithium-batteries-catch-fire-606814. Helmenstine, Anne Marie, Ph.D. (2023, April 5). Why Lithium Batteries Catch Fire. Retrieved from https://www.thoughtco.com/why-lithium-batteries-catch-fire-606814 Helmenstine, Anne Marie, Ph.D. "Why Lithium Batteries Catch Fire." ThoughtCo. https://www.thoughtco.com/why-lithium-batteries-catch-fire-606814 (accessed May 31, 2023).