Analysis of The Causes of Fire And Explosion of 18650 Lithium Batteries And Countermeasures

Analysis of the causes of fire and explosion of 18650 lithium batteries and countermeasures

Due to their high energy density and long cycle life, 18650 lithium batteries are widely used in consumer electronics, power tools, electric vehicles and other fields. However, the chemical characteristics of lithium batteries determine that they may catch fire or even explode under extreme conditions, causing serious safety accidents. This article will start from the working principle of lithium batteries, analyze the causes of their fire and explosion, and provide corresponding countermeasures to help users better understand and use lithium batteries.

1. Working principle and potential risks of lithium batteries

18650 lithium battery is a typical lithium-ion battery, and its working principle is based on the reversible insertion and extraction of lithium ions between positive and negative electrode materials. During the charging process, lithium ions are extracted from the positive electrode material and embedded in the negative electrode material through the electrolyte; the discharge process is the opposite. Although this electrochemical reaction is efficient, it also has certain risks:

Flammability of electrolyte: The electrolyte of lithium batteries is usually an organic solvent and is flammable. Once a short circuit or overheating occurs inside the battery, the electrolyte may be ignited, causing a fire.

High energy density: The energy density of lithium batteries is much higher than that of traditional batteries, which means that when thermal runaway occurs, the energy released is greater and may cause an explosion.

Runaway chemical reaction: When the battery is overcharged, over-discharged or mechanically damaged, the internal chemical reaction may get out of control, generating a large amount of heat and gas, causing the battery to swell, rupture or even explode.

2. The main reasons for lithium battery fire and explosion

Overcharge: When the battery charging voltage exceeds its upper limit, the excessive release of lithium ions in the positive electrode material may cause the positive electrode structure to collapse, and lithium dendrites may form on the surface of the negative electrode, piercing the diaphragm and causing an internal short circuit.

Overdischarge: When the battery discharge voltage is lower than its lower limit, the excessive release of lithium ions in the negative electrode material may cause damage to the negative electrode structure, and the electrolyte may decompose, generating gas and heat.

Short circuit: When the positive and negative electrodes of the battery are directly in contact or connected through an external conductor, a large current will pass through the battery, generating a large amount of heat and causing thermal runaway.

High temperature environment: High temperature will accelerate the chemical reaction inside the battery, causing the electrolyte to decompose, the diaphragm to shrink or even melt, and increase the risk of short circuit.

Mechanical damage: When the battery is subjected to mechanical damage such as squeezing, impact or puncture, it may cause internal short circuit or electrolyte leakage, causing fire and explosion.

III. Countermeasures: Prevention first, timely treatment

To avoid lithium battery fire and explosion, users need to take the following precautions:

Use qualified chargers and batteries: Choose certified chargers and battery products, and avoid using inferior or counterfeit products.

Avoid overcharge and overdischarge: Use a charger with overcharge and overdischarge protection function, and charge when the battery power remains 20%-30%.

Prevent short circuit: When storing and using batteries, avoid the positive and negative poles of the battery from contacting metal objects. You can use a battery box or insulating tape for protection.

Control temperature: Avoid exposing the battery to high temperature environments, such as direct sunlight, high temperature in the car, etc.; when charging and using, pay attention to the battery temperature. If the temperature rises abnormally, stop using it immediately and check the cause.

Avoid mechanical damage: When using and storing batteries, avoid mechanical damage such as squeezing, impact or puncture.

Regular inspection: Check the appearance of the battery regularly for damage, deformation, leakage, etc. If any abnormality is found, stop using it immediately and handle it properly.

IV. Emergency treatment methods for fire and explosion

If a lithium battery catches fire and explodes, the following emergency treatment measures should be taken:

Rapid isolation: Move the battery on fire to a safe area to prevent the fire from spreading.

Use a fire extinguisher: Use a dry powder fire extinguisher or a carbon dioxide fire extinguisher to extinguish the fire. Never use water to extinguish the fire, because water will react with lithium and intensify the fire.

Cooling treatment: Cover the battery with sand or a special lithium battery fire blanket to prevent re-ignition.

Call the police for help: If the fire cannot be controlled, call the fire alarm for help immediately.

V. Conclusion

Although the fire and explosion of 18650 lithium batteries are rare, the consequences can be very serious. Users need to fully understand the safety risks of lithium batteries and take effective preventive measures to minimize the occurrence of safety accidents. At the same time, mastering the correct emergency treatment methods can minimize the losses when accidents occur. I hope that the analysis and suggestions in this article can help you better understand and use 18650 lithium batteries to ensure safety.