Do electric vehicles catch fire more often? Early evidence says no

In 2023, a devastating fire tore through a housing block in Hanoi, Vietnam, killing more than 50 people. Rumors quickly blamed the blaze on a battery-powered electric two-wheeler, and numerous apartment buildings in Hanoi banned EV charging stations in the incident’s aftermath – but authorities said that the fire had actually begun in a gasoline-powered scooter.

You’ll see many other messages on social media claiming that EVs are fire-prone or that EV fires are more dangerous than those of gasoline- or diesel-powered combustion vehicles. Burning EVs, as shown in this TikTok post, regularly attract tens of thousands of views. Or see this 2023 post on X/Twitter, which accrued nearly 900,000 views after claiming that EVs are “prone to spontaneously bursting into flames—which are virtually impossible to put out”.

It’s not hard to find EV fires in the news. Take the MV Fremantle Highway, a cargo ship that caught fire off the Dutch coast in July 2023. Numerous articles highlighted the fact that the Fremantle Highway was carrying a shipment of several hundred EVs – but later reporting suggested that the EVs were perfectly intact and that the fire began on a different deck.

These claims usually blame fires on the one part of an EV that you won’t find in a pure combustion vehicle: the lithium-ion battery. But are fears of battery fires actually justified?

Lithium-ion batteries can combust, and EV fires are more difficult to put out than combustion vehicle fires. But as we’ll show, EV battery fires like these are quite rare. In fact, the data suggests that EVs are actually quite a bit less likely to catch fire than cars with a gasoline- or diesel-powered internal combustion engine.

Current evidence suggests EV battery fires are very rare

These claims may leave the impression that every EV you see is a ticking time bomb. But how many EV batteries have actually ignited?

EV FireSafe – a private company funded by the Australian government – collects data to answer this question. Around the world, they’ve verified 511 EV* battery fires between 2010 and June 2024. For comparison, according to the International Energy Agency (IEA), 40 million EVs were on the road by the end of 2023, and 17 million new EVs were sold in 2024 alone. 

That translates to about one battery fire in 15 years for every 80,000 EVs. EV FireSafe told Science Feedback there are likely many other battery fires they haven’t recorded, but even if the actual number is several times higher, battery fires may still only account for a tiny fraction of active EVs – fewer than 1 in 10,000. 

You might see stories calling attention to an “alarming trend” that the number of EV fires is growing. But that shouldn’t be surprising – the number of EVs on the road has dramatically increased, so naturally the number of battery fires could increase too^[1]. This doesn’t necessarily mean a given EV is more likely to catch fire (Figure 1).

Importantly, not all EV fires are battery fires. As we’ll see below, data suggests that only around 25% of EV fires actually involve the battery. EVs can ignite due to an electrical short-circuit, due to carrying a flammable item, or even due to arson (all of which can affect combustion vehicles too) and these types of fires may not reach the battery at all. 

So, why do EV fires gain so much attention on social media and in the news? There’s certainly a lot of misinformation targeting EVs. Another likely answer is that EV fires tend to capture a lot of attention because EVs are a new technology. Greg Less, Director of the University of Michigan Battery Lab, told Science Feedback:

“I think it’s important that we remember that we talk a lot about EV fires because EVs are new. It’s a new product. It’s fresh on the market, and when a few of them catch fire, it’s a big news flash. But every day, all around the world, hundreds if not thousands of internal combustion vehicles catch fire, and it’s not news, because it’s a hundred-year-old technology.”

If that’s the case, then how do EVs compare to combustion vehicles?

*Note: by “EVs” we mean all vehicles with a plug-in battery – both fully battery-powered vehicles and plug-in hybrids.

Do EVs catch fire more often than combustion vehicles?

This is a difficult question to answer with confidence, because we don’t have enough data. Even countries with many EVs often don’t release counts of how many catch fire. However, when we examine the few countries that do offer their data, we find some evidence that EVs are less fire-prone than combustion vehicles.

In Norway (where more than 90% of new cars are now EVs) in 2024, a fully battery-powered vehicle (BEV) had an approximately 1 in 12,500 chance of catching on fire that year, compared to a 1 in 2,500 chance for a non-BEV. In other words, BEVs were around 5 times less likely to catch fire than other cars.

Numbers from South Korea and Sweden also suggest EVs are several times less likely to catch fire than their internal-combustion-powered counterparts.

There are several caveats here. For one, the vast majority of EVs are only a few years old, and we’re not sure what might happen as they continue to age. Many combustion vehicle fires happen in cars that have been modified or repaired at home – it’s possible that we’ll see more of the same with EVs as they age.

Additionally, we can’t directly compare these national numbers to EV FireSafe’s, because the national numbers include all types of fires. For example, if a garage catches fire due to a mains electrical fault in the wall, and if the fire happens to damage an EV inside the garage, the incident may be recorded as an “EV fire” even though the EV didn’t cause the fire. 

And, as we’ve seen, not all EV fires are alike – only an estimated 25% of EV fires actually involve the battery. That figure comes from the Netherlands, the only country that records the causes of EV fires – of 136 EV fires with known causes recorded in the Netherlands in 2023, just 31 involved the battery. Most EV fires didn’t touch the battery at all.

All that said, there’s currently no evidence to suggest that EVs are more dangerous than combustion vehicles. On the contrary, the evidence we do have suggests that EVs are actually quite a bit less fire-prone than their combustion counterparts. (Combustion vehicles are powered by a highly flammable liquid, after all.)

Are EV battery fires more dangerous?

So, EV battery fires are very rare. But is a battery fire different from – or more hazardous than – a petrol or diesel fire? In some ways, yes. To understand why, let’s explore how an EV battery works and how it can go wrong. 

In essence, a battery is a way of storing energy in chemical form. A typical EV’s battery contains a number of lithium-ion cells. Within each cell, controlled chemical reactions turn the stored energy into the electricity that powers an EV. Charging up the battery effectively reverses these reactions and stores more energy to be used later. 

An EV’s battery is designed to discharge and recharge thousands of times safely. But when something goes wrong – if a battery is punctured, or crushed, or overheated – one of its cells may short-circuit and snap into a different and uncontrolled chemical reaction. 

This malfunctioning cell generates heat and flammable gases, especially hydrogen. If that heat spreads from one cell to its neighbors, it can cause them to overheat, too. The resulting runaway reaction is called ‘thermal runaway’ (Figure 2).

A thermal runaway gives us all three key ingredients of a fire: fuel (the flammable gases), oxygen, and heat. As the gases escape, sometimes visible as puffs of vapor, they can ignite as jets of fire. If the gases are trapped inside the vehicle, they can trigger a violent explosion (though these vapor cloud explosions seem to be a very small fraction of already-rare battery fires – around 10% of them, according to EV FireSafe).

To fight this sort of fire, you must stop the thermal runaway by cooling down the overheating cells. Even if you completely put out a fire on the outside, the battery can re-ignite if the cells are hot enough. The problem is that the cells are usually wrapped within a metal casing – firefighters can’t directly reach them.

So firefighters often require special methods. In Europe, for example, firefighters often respond to battery fires by dunking either the battery or the entire vehicle in a tank of water. But because EVs are relatively new, today’s firefighters and other first responders may not have the equipment or the training to handle them.

This all might sound quite alarming, but this only applies to the small fraction of EV fires which actually involve the battery. Dan Fish, Head of Technical at EV FireSafe, told Science Feedback:

“Only about 25% of EV fires actually involve the battery pack. The other 75% can be managed just like any other car fire.”

Moreover, evidence and experts say that EV batteries are extremely safe on the whole. Any EV battery must pass rigorous safety standards in order to be sold internationally.

If lithium-ion batteries are a fire risk, then the riskier devices are those like electric bikes, e-scooters, vapes, and power packs. EV FireSafe noted to Science Feedback that these sorts of devices often don’t meet the same high standards as EVs, and they often include cheaply made batteries that are far more likely to combust (Figure 3). Emma Sutcliffe, Director of EV FireSafe, told Science Feedback:

“When we talk about lithium-ion battery fires, the problem is very, very firmly with these smaller, cheap, poor-quality devices – but electric cars seem to get all the attention.”

Scientists are trying to make batteries safer

It’s good to ask questions about EV battery safety, because the scientists and engineers making these sorts of batteries are asking the same questions.

This is especially true because lithium-ion batteries are – again – a relatively new technology, as Less told Science Feedback:

“I think we need to also remember that the first commercial lithium-ion battery was in 1990. That was only 35 years ago. We’ve had internal combustion engines for over 100 years, and have been iterating and making them safer this whole time.”

Indeed, battery developers want to ensure their creations are as safe as possible. Safety testing is a key step of battery design^[2]. Part of that is what engineers call abuse testing – researchers intentionally break, crush, pierce, overheat, and destroy a battery to better understand what causes batteries to catch fire.

With the knowledge they gain, engineers can rearrange a battery’s layout to reduce the risk that thermal runaway will spread from cell to cell. Or engineers can build the cells from less fire-prone materials.

For example, the standard EV battery of several years ago relied on a material called NMC. However, many EV batteries today, including Tesla’s and BYD’s, instead use lithium iron phosphate (LFP). One reason for the switch is that LFP batteries are safer – tests in the lab have shown that LFP batteries are less prone to thermal runaway^[3,4].

References

• 1 – Lai et al. (2022) A Review of Lithium-Ion Battery Failure Hazards: Test Standards, Accident Analysis, and Safety Suggestions. Batteries.
• 2 – Jaugemont and Bardé (2023) A critical review of lithium-ion battery safety testing and standards. Applied Thermal Engineering.
• 3 – Schöberl et al. (2024) Thermal runaway propagation in automotive lithium-ion batteries with NMC-811 and LFP cathodes: Safety requirements and impact on system integration. eTransportation.
• 4 – Pastor et al. (2023) Analysis of the aging effects on the thermal runaway characteristics of Lithium-Ion cells through stepwise reactions. Applied Thermal Engineering.