Fire Blanket vs. Fire Extinguisher: Which Is More Effective Against Lithium Battery Fires?

Which is more effective, a fire blanket or a fire extinguisher, when it comes to lithium battery fires in electric vehicles?
In the case of lithium battery fires, fire blankets and fire extinguishers each have distinct characteristics, making it difficult to simply declare one stronger than the other. Here is an analysis based on practical tests:

1. Fire blankets are effective in controlling fires and can prevent flame spread for at least 60 minutes. When covering a fire, they significantly reduce the temperature in the surrounding area, protecting adjacent equipment and personnel. They also offer some smoke emission control, as they allow partial release of combustible gases produced during battery thermal runaway about 10 minutes after covering. This greatly reduces the risk of gas accumulation and explosion. Even after 60 minutes of exposure to high temperatures, fire blankets retain a certain degree of flexibility and can be reused multiple times.

2. Dry powder fire extinguishers can quickly extinguish open flames but are ineffective against the internal thermal runaway of lithium batteries, often leading to re-ignition. Tests show that a large amount of dry powder is required to temporarily control the fire, and lithium batteries may re-ignite multiple times.

3. Water-based fire extinguishers form a water film that isolates oxygen while cooling the battery, offering better resistance to re-ignition compared to dry powder extinguishers. They can penetrate the battery surface, reducing the affected area, but they cannot fully stop the internal chemical reactions of lithium batteries, necessitating repeated spraying.

4. Some specialized lithium battery fire extinguishers can penetrate the battery interior, suppress chemical reactions, and carry a lower risk of re-ignition. However, such products are not yet widely available and require proper use to achieve their intended effect.

• If the goal is to control fire spread and protect the surrounding environment, fire blankets are more effective, as they can quickly isolate the fire source and minimize secondary hazards.

• If the goal is to extinguish open flames and reduce the risk of re-ignition, water-based or specialized lithium battery fire extinguishers are more suitable, but continuous operation is necessary.

For internal thermal runaway in lithium batteries, no single tool can completely resolve the issue. Comprehensive measures, including extensive water cooling and professional firefighting equipment, are required.

In practical use, prioritize personal safety, stay away from the fire source, and call for emergency assistance immediately. If conditions permit, consider using a fire blanket to control the fire first, then follow up with a fire extinguisher or water for further suppression.