Reports of lithium battery fires and explosions are common, raising concerns about their safety. These fires spread quickly, burn at high temperatures, and are difficult to extinguish. Prolonged exposure of lithium batteries to specific conditions can lead to combustion or even explosion, making fire prevention measures crucial.
Part 1. Why Do Lithium Batteries Catch Fire and Explode?
Lithium-ion batteries contain flammable components and can be a source of ignition. Factors such as collisions, squeezing, overcharging, or short circuits can significantly increase the risk of fire and explosion.
Lithium batteries function through the movement of lithium ions between the positive and negative electrodes via an electrolyte during charging and discharging. The main reasons for lithium battery explosions are overcharging and short circuits.
1. Lithium Battery Overcharging
Overcharging occurs during the charging process when the battery accumulates excessive heat due to its internal resistance. Although built-in protection devices can detect voltage changes to some extent and prevent overcharging, prolonged overcharging at excessively high voltages can still lead to dendritic short circuits. These short circuits can cause rapid increases in temperature and pressure, increasing the risk of fire and explosion.
2. Lithium Battery Short Circuit
What is a Lithium Battery Short Circuit?
Short circuits often occur during battery operation when the battery’s internal temperature rises above its normal operating range. Under extreme heat or external pressure, the separator inside the battery may be damaged, leading to an internal short circuit. This generates excessive heat, triggering a chain reaction that can cause the battery to ignite or explode.
Part 2. Ignition Temperature of Lithium Batteries
The ignition temperature of a lithium battery depends on its type and material composition, among other factors. Most lithium batteries used in mobile phones, power banks, and electric vehicles are designed for operation at room temperature, with an optimal operating temperature range of 0°C-60°C. Exceeding this limit increases the risk of fire and explosion. If a lithium battery reaches 60°C during charging, caution is required.
The temperature resistance of lithium batteries depends on their category:
- High-Temperature Lithium Batteries: Can operate at extreme temperatures up to 800°C.
- Low-Temperature Lithium Batteries: Can operate effectively at temperatures as low as -50°C.
In everyday applications, most lithium batteries are room temperature types, with a maximum tolerance below 60°C. They are more prone to fire or explosion when exposed to excessive heat, whether from external or internal sources.
Lithium Battery Temperature Reaching 70°C During Charging
Lithium batteries naturally generate heat during charging. However, if the temperature reaches 70°C, it indicates an abnormal situation. Several factors can cause excessive heat buildup, including:
- Internal short circuit
- Battery aging
- Using an incompatible charger
- Overcharging
- Low electrolyte level
- High ambient temperature
Identifying these warning signs early can help prevent potential lithium battery fires.
Conclusion
Understanding the causes of lithium battery fires, ignition temperature limits, and the importance of preventing overcharging and short circuits can help improve battery safety. By following proper usage guidelines, avoiding overheating, and using correct charging methods, the risk of accidents associated with lithium batteries can be significantly reduced. By understanding these factors and implementing preventative measures, users can significantly reduce the risk associated with lithium battery usage. For more insights on Lithium Iron Phosphate Batteries, be sure to check out our detailed guide.
How to Prevent Lithium Battery Overheating and Fire
Part 1: What to Do When a Lithium Battery Overheats
If your lithium battery starts to overheat while charging, the first thing you should do is unplug the charger immediately. Next, investigate the cause of the overheating. To address lithium battery overheating, you may need to replace the charger or battery, replenish the electrolyte, repair internal short circuits, or adjust the ambient temperature.
Part 2: How to Prevent Lithium Batteries from Catching Fire and Exploding
Proper Selection and Use of Lithium Batteries
To minimize the risk of fire or explosion, keep the following tips in mind when selecting and using lithium batteries:
- Always purchase lithium batteries and tools from reputable sources that meet safety standards.
- When not in use, remove the battery from the device and store it separately in a safe location.
- Keep lithium batteries away from moisture and extreme temperatures, and ensure they are away from flammable or combustible materials.
- Disconnect lithium batteries from the power source immediately after they are fully charged to avoid overcharging.
- Avoid squeezing or dropping lithium battery products, as physical damage can compromise safety.
Part 3: What to Do When a Lithium Battery Catches Fire or Explodes
How to Handle Lithium Battery Fires
If a lithium battery catches fire, a dry powder fire extinguisher may extinguish the surrounding flames, but it will not stop the thermal runaway reaction within the battery. The best emergency measure to handle lithium battery fires is to use water or water-based fire extinguishers.
- Water is the preferred choice for extinguishing low-voltage lithium battery fires because there is minimal risk of electric shock.
- However, if the lithium battery is connected to an AC power source when it catches fire, disconnect the power before using water to extinguish it. Failure to do so may lead to electric shock or a secondary fire or explosion due to water electrolysis in a 220V AC circuit.
How to Handle Lithium Battery Fires
- Disconnect or remove the external power supply on the burning device.
- Continuously soak the device with water or a non-flammable liquid to lower the temperature of the lithium battery cells and prevent nearby cells from igniting.
- If the device is connected to a power outlet, disconnect all power sources only after ensuring it is safe to do so.
- Never move burning or smoking electronic devices to prevent serious injury.
- Never cover a burning device with ice, as it can hinder heat dissipation, potentially worsening the fire.
