Lithium-Ion Battery Fires: How Hot They Get, Why They Happen, and How to Stop Them
Lithium-ion batteries are super important today. They power our phones and even electric cars. But they can sometimes catch fire. This often happens because of something called thermal runaway, which is when the battery gets too hot very quickly and can't cool down. This article will look at how hot lithium-ion battery fires can get. We will also explain why thermal runaway happens and what new safety ideas can help.
Why Batteries Can Overheat (Thermal Runaway)
Thermal runaway starts when something inside or outside the battery makes it unstable. For instance, if a battery gets damaged, that can cause problems. Overcharging it or being in very hot weather can also start a dangerous chain reaction inside. Research shows that lithium battery fire temperatures can jump from 90°C to over 1,600°C in just seconds. How hot it gets depends on what the battery is made of and how much charge it has.
How Temperatures Get Dangerously High
Things Start to Heat Up (90–125°C):
A protective layer inside the battery begins to break down. This breakdown lets reactive parts of the lithium touch flammable liquids inside. This action creates heat and also makes gases like methane and ethylene.
The Separator Fails (125–180°C):
Next, the thin plastic sheet called a separator melts. This sheet usually keeps different parts of the battery from touching, so when it melts, it causes short circuits inside. Then, some materials in the battery, like those with nickel, start to release oxygen. This oxygen makes any fire burn much faster.
Full Overheating and Fire (>180°C):
At temperatures above 180°C, full thermal runaway occurs. The heat suddenly skyrockets to 1,500–1,625°C. This can be joined by explosions and the release of dangerous gases, such as hydrogen fluoride and carbon monoxide.
For example, a 2024 study at Penn State University found something interesting. Some special lithium-metal batteries can catch fire in only 1 to 3 seconds if they have a short circuit, because the lithium reacts directly with oxygen.
What Makes Fires Worse
How bad a lithium-ion battery fire temperature gets depends on several things.
What the Cathode is Made Of:
Battery parts called cathodes that have a lot of nickel tend to create more heat. Other types, like lithium iron phosphate, are more stable and don't get as hot.
The Liquid Inside (Electrolyte):
The type of liquid electrolyte inside the battery also matters. Older kinds, made from carbonates, can catch fire at around 150°C. Newer electrolytes have special additives mixed in. These additives can help delay a fire from starting.
How the Battery is Used and Stored:
The conditions in which a battery is used are also very important. Batteries that are fully charged (100%) release almost twice as much heat if they fail compared to batteries that are only half-charged. Storing batteries in places warmer than 35°C also makes them wear out faster.
Safety Rules and New Ideas
To deal with the risks of lithium battery fire temperatures, we need good ways to prevent fires and to put them out.
Problems with Fighting These Fires
Normal ways of fighting fires, like using water or dry powder, often don't work very well. These substances often can't get into the tightly packed battery parts. But there are some new breakthroughs.
• Special Fire-Fighting Agents:
One company, Fipukawa, makes special fire suppressants just for lithium batteries. These can soak up a lot of heat (1,400 kJ/kg) and also get rid of harmful fumes.
• Better Sprinkler Systems:
Computer tests in 2023, using something called PyroSim, showed that improved sprinkler systems can make a big difference. They can reduce the highest heat output in warehouse fires from a huge 81,607 kW/s down to a much smaller 6.5 kW/s.
Technologies to Prevent Fires
• Battery Management Systems (BMS):
Modern BMS are like little computers that constantly watch the battery. They check its voltage, temperature, and even if it's starting to swell up, to spot early signs that something is wrong.
• New Materials:
Scientists are also creating new materials to make batteries safer. For example, separators coated with ceramic can stay stable up to 200°C, and solid-state electrolytes (which aren't liquid) greatly reduce the risk of fire.
Learning from Real Fires and Tests
Electric Car Fires:
A 2025 study of electric vehicle fires showed an important difference. Thermal runaway spreads about 30% faster in batteries that use a lot of nickel compared to the safer lithium iron phosphate (LiFePO₄) types.
Warehouse Storage Dangers:
A test fire in a pretend shipping center showed how quickly things can become dangerous. Harmful smoke spread in only 35 seconds, and levels of bad carbon monoxide gas went above 1.799×10⁻³ parts per million.
What's Next for Battery Safety
Solid-State Batteries:
These batteries are a promising new technology. They don't use flammable liquid electrolytes, which is a big safety plus. However, they still need special layers to block oxygen from reaching the lithium metal, which could otherwise burn.
AI to Predict Problems:
Artificial intelligence (AI) could also play a big role. Smart computer programs, using machine learning, can analyze small changes in a battery’s voltage or how much it's expanding. These programs might be able to predict if a thermal runaway event is going to happen up to 2 hours before it actually does.
Understanding how hot lithium-ion battery fires can get is very important for reducing risks, especially in energy storage systems and in transportation like electric cars. By using advanced materials, AI monitoring, and new safety rules, industries can find a good balance between making batteries that perform well and making them safe. For the best results, experts suggest storing lithium-ion batteries in places cooler than 35°C. They also recommend keeping the battery charge between 40% and 60% if you plan to store them for a long time.
