Water is the most effective tool for putting out a lithium-ion battery fire. That surprises most people, but lithium-ion batteries are not the same as pure lithium metal, and the fire they produce behaves differently. The key challenge isn’t knocking down the flames. It’s cooling the battery enough to stop the chain reaction inside it and preventing reignition, which can happen hours or even days later.
Why These Fires Are Different
A lithium-ion battery fire starts with a process called thermal runaway. When a cell is damaged, overcharged, or overheated, its internal layers begin breaking down in a cascade of heat-generating chemical reactions. The first reactions kick off around 80 to 125°C (roughly 175 to 260°F), as the protective layer inside the cell decomposes and the stored materials start reacting with the liquid electrolyte. As temperature climbs, the cathode releases oxygen, which feeds more reactions. The result is a self-sustaining loop: each reaction generates heat that triggers the next one.
This is why simply smothering the flames doesn’t work well. The oxygen fueling the fire is partly coming from inside the battery itself, not just the surrounding air. Cutting off external oxygen with a blanket or a CO2 extinguisher won’t stop the internal chemistry. You need to cool the cells below the temperature where those reactions can continue.
Small Device Fires: Phones, Laptops, and Power Tools
If a phone, laptop, or small battery pack starts swelling, smoking, or burning, move it away from anything flammable if you can do so safely. Push it off a table onto a tile or concrete floor, or use a non-flammable object to slide it. Don’t pick it up with bare hands.
For a small, contained fire, pour water directly onto the device. A significant amount of water is ideal, not a splash. If you have a standard ABC dry chemical fire extinguisher (the red canister most homes and offices have), it can knock down the open flames, but it won’t cool the battery. Follow up with water. If you only have water, that alone is your best option. Keep pouring until the device stops hissing and producing smoke.
Once the fire appears out, don’t assume it’s over. Place the device somewhere non-flammable, ideally outdoors on concrete, and monitor it. Lithium battery fires can reignite from residual heat trapped inside cells that haven’t fully cooled. Stay away from it for several hours and keep a water source nearby. Ventilate the room thoroughly afterward.
What Not to Use
Class D fire extinguishers are designed for burning metals like magnesium shavings in machine shops. They are not effective on lithium-ion battery fires. Lithium-ion cells contain very little metallic lithium. The fire is driven by chemical reactions between the electrolyte, electrodes, and internally generated oxygen, which makes it closer to a Class B flammable-liquid fire. A Class D extinguisher on a lithium-ion fire performs about as well as spraying the same volume of plain tap water, without any of water’s cooling benefit.
One important distinction: old-style non-rechargeable lithium batteries (like some hearing-aid batteries) do contain metallic lithium and produce true metal fires. Those are Class D situations. But the rechargeable lithium-ion batteries in virtually every modern device, e-bike, and electric vehicle are not.
Sand and fire blankets can contain a small fire from spreading but won’t stop thermal runaway. CO2 extinguishers displace oxygen but, again, the battery generates its own oxygen internally. These tools buy time but don’t solve the core problem of heat.
Electric Vehicle Battery Fires
EV battery fires are a different scale entirely. The battery pack in an electric car contains thousands of individual cells, and thermal runaway can spread from cell to cell over minutes or hours. The International Association of Fire Chiefs recommends fire departments secure a continuous water supply of 3,000 to 8,000 gallons for an EV fire, compared to the few hundred gallons a typical car fire might need.
If you witness an EV fire, get everyone well away from the vehicle and call emergency services immediately. This is not something bystanders can handle. These fires burn longer, require extended suppression, and fire departments plan for prolonged operations with ongoing monitoring for secondary ignition. Even after the flames are out, the battery pack can reignite during towing or storage, so professional assessment is essential.
E-Bike and Scooter Battery Fires
E-bike batteries sit in a dangerous middle ground: too large and energetic for easy household suppression, but stored inside homes where fires are most dangerous. Many e-bike fires start during charging, particularly with aftermarket or damaged batteries. If an e-bike battery begins venting (hissing, swelling, or producing white smoke), get it outside immediately if you can do so in the first few seconds. Once flames appear, evacuate and call 911.
Fire-resistant storage bags marketed for e-bike batteries have limited real-world effectiveness. These batteries can reach roughly 2,000°F during thermal runaway, which is enough to melt through most containment products. The better strategy is prevention: charge batteries in a well-ventilated area away from exits, never leave them charging overnight or unattended, store them at a partial charge (manufacturers like Bosch recommend 30 to 70 percent for long-term storage), and replace any battery that has been dropped, damaged, or is visibly swollen.
Toxic Fumes Are the Hidden Danger
The smoke from a lithium-ion battery fire is genuinely hazardous, and in enclosed spaces, the fumes can be a bigger threat than the flames. Burning cells release hydrogen fluoride, a highly toxic gas, in quantities ranging from 20 to 200 milligrams per watt-hour of battery capacity. A typical laptop battery is around 50 to 60 watt-hours. An e-bike battery might be 500 watt-hours. The math gets alarming quickly.
These fires also produce carbon monoxide, carbon dioxide in oxygen-displacing concentrations, and phosphoryl fluoride, another toxic fluorine compound. This is why confined spaces like apartments, aircraft cabins, and garages are especially dangerous during a battery fire. If a battery fire starts indoors, your first priority is getting people out and opening windows or doors on your way. Do not stay in a room trying to fight a battery fire without ventilation. Even after the fire is out, air out the space thoroughly before spending time in it.
Reignition: The Threat That Lasts
The U.S. Fire Administration warns that lithium-ion battery fires carry a persistent reignition risk even after the fire appears fully extinguished. Internal cells that weren’t directly cooled can continue heating until they enter thermal runaway on their own, potentially hours later. This is why fire departments monitor EV fires for extended periods and why a phone that caught fire should sit on concrete outdoors, not go into a trash can.
For any battery fire you manage to suppress, keep checking the device or battery pack periodically for warmth, swelling, or new smoke. If reignition occurs, apply water again. For anything larger than a single small device, let professionals handle the monitoring. The safest approach after putting out a battery fire at home is to move the device outside, keep it isolated from structures and flammable materials, and let it sit for at least 24 hours.