Simple science explains why EV’s can be a fire risk.
But it also explains why traditional combustion engines carry the same risk.
People all over the internet are debating whether electric vehicles catch fire or “explode” faster and easier than those with traditional internal combustion engines. A rise in popularity of the topic can mostly be traced back to some bad publicity and a number of Tesla electric vehicles catching fire and reportedly bursting into flames.
In this post, I want to discuss the science behind whether these electric vehicles that Tesla popularized are more of a fire and explosion risk versus vehicles with an internal combustion engine. We’re also gonna look at some ways to potentially prevent fires in battery-electric and hybrid vehicles with the hope of saving some drivers from a disaster.
Understanding the technology used in EV batteries
When I say that simple science is to blame for most of the electric vehicles that catch fire, it’s the lithium-ion batteries specifically. In order to figure out why an EV or plug-in hybrid is at a higher risk of catching fire we have to first understand the lithium-ion batteries that power these vehicles.
What is a lithium-ion battery?
With everything from consumer electronics to modern transportation vehicles in 2023 requiring more electrical energy, it’s lithium-ion batteries taking the charge (literally) and becoming the leading source of portable power. But what is a good way to explain the lithium-ion battery so that every day people can understand what their electronics and cars are being powered by?
According to UL Research Institutes, the way a lithium-ion battery works can be explained like this-
In a lithium-ion battery, lithium ions (Li+) move between the cathode and anode internally. Electrons move in the opposite direction in the external circuit. This migration is the reason the battery powers the device—because it creates the electrical current.
Although this is still a confusing way to understand how lithium-ion batteries produce power, it is the best way to define the most popular batteries being used in 2023 that I could find.
Essentially what Underwriters Laboratories is saying about Li+ batteries is that there are two sides-an anode and a cathode. When the battery is giving energy to a device, the anode is releasing lithium ions to the cathode which causes electrons to flow and in turn release energy to the device it is assembled to. Still a little confusing, but if you take a look at this photo it might be a little easier to understand how a lithium battery charges and discharges.
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What causes a lithium-ion battery to catch fire?
By now it’s clear, the reason that EV’s catch fire or explode more than internal combustion engine vehicles is due to the lithium-ion battery that powers them. What is it about lithium-ion batteries that causes them to catch fire though?
According to ionenergy.co, a process known as thermal runaway is the leading cause of fire in a lithium-ion battery. In this dangerous process, a battery cell is forced to release all of its energy within milliseconds due to instability caused by heat or damage to the cell itself.
With a typical EV battery being made up of thousands of these cells, it’s not hard to understand how thermal runaway can turn into a chain reaction of bursting flames often describes as “sparklers going off” from the battery area.
Why are EV batteries a higher risk of fire versus say a drill battery?
Any lithium-ion battery can cause a fire, especially when damage causes instability but the highest risk for a life-threatening fire comes from the batteries that power any type of battery-electric vehicle. There are several reasons an EV battery fire can be life-threatening and are far more serious than that of a consumer electronic battery.
Defective manufacturing process
A manufacturer defect is something that everyone reading this post can identify with. I’d be willing to bet everyone reading this has bought a product with a defect from the manufacturer at one time or another. It’s okay when it’s something like a stripped bolt, a radio that doesn’t work out of the box but what happens when the human element in manufacturing causes a defect in a lithium-ion battery?
Any defect in the manufacturing process of an EV battery or any lithium-ion battery that causes a rise in temperature can have serious consequences to the owner of the vehicle. It’s essentially like putting a wrench across the negative and positive terminals of your traditional car battery and watching it turn red hot.
If for any reason current starts to flow between the positive and negative plates of a lithium-ion battery, the temperature will rise and could cause a heat significant enough to force the battery to discharge in the form of “thermal runaway.”
Damage to the Li+ cell.
Damage to the lithium-ion battery cell is a significant reason electric vehicle batteries catch fire in 2023. A rise in imperfect features such as Auto-pilot from Tesla seem fated to cause even more of these EV battery fires in the near future. Even without auto-pilot though, there is always a risk of damage to a vehicle when it is put on the road or out in the field in the case of electrical industrial equipment.
Even with vehicles powered by a traditional ICE, damage is a leading cause of fires due to the combustible fuel sources being used to create the energy that powers the vehicle. I think a key difference is, cars with a fuel delivery system have been tested and fine tuned for a century in order to find ways to prevent fires. Electric vehicles can surely use some of this safety and testing data to develop battery damage protection protocols in manufacturing- but it’s still new territory.
Number of cells in an EV battery
One key difference between say a Milwaukee M18 battery and an EV battery is the number of cells needed to produce the energy needed to power it. Consider that a Tesla Model S 99kWh battery pack contains 18,650 individual cells to produce that amount of capacity compared to a 4.0 Ah M18 battery that contains 15 li-ion cells.
No doubt a Milwaukee battery catching on fire is dangerous to the user and the building it catches fire in, but the number of cells used in a Tesla or other EV battery means a much larger “chain reaction” of sparklers shooting flames out when the cells start to discharge.
Are EV batteries more likely to catch fire?
Since the rise in popularity of EV’s, battery fires have been a hot topic thanks in part to graphic images of Tesla’s exploding in flames circulating the internet. Is there any truth to the claim that battery-electric vehicles are more prone to catching fire though– or is this just a media-driven myth?
The answer isn’t clear but according to Tesla, the leading manufacturer of fully electric vehicles, they have 5 fires per billion miles compared to internal combustion engines that catch fire at a rate of 55 per billion miles. Tesla would obviously have a huge reason to skew the data on vehicle battery fires in their favor, so that number remains in question.
Features like auto-pilot may increase the risk.
One of the articles I read recently was a report of a Model X on auto-pilot crashing into a guardrail and “bursting into flames” almost immediately. According to the report, the auto-pilot feature malfunctioned and caused the car to veer left and hit the guard rail, damaging the battery and causing it to catch fire in the process.
As we talked about earlier, damage to the battery is one of the leading reasons for an EV battery cell to catch on fire is damage. Drivers using a largely unproven and sketchy feature like auto-pilot in an automobile may prove to increase the risk of electrical fires in Tesla and other battery-electric vehicles.
Can we prevent EV battery fires in the future?
In a political landscape offering subsidies to auto manufacturers incentivizing the production of more battery-electric vehicles in 2023 and beyond, it’s important that we come up with a better way to prevent these fires caused by lithium-ion batteries.
Some ideas proposed by different sources to prevent EV battery fires include increased cooling methods, higher-quality components and better charging methods like smart-charging capabilities offered in certain home EV chargers.
Tesla released what it calls a “first responders guide” to extinguishing electric vehicle battery fires in hopes of offering guidance to fire fighters and other front-line workers when dealing with a battery fire.
One thing is clear in 2023 and that’s the debate on electric vehicle battery fires is just starting to heat up and the more we know and understand about lithium-ion battery fires, the better we will be at preventing deaths caused by them.
What’s your take on EV and lithium-ion battery fires?
If you have something to add to the debate surrounding battery-electric vehicles and the risk of fire, let me know in the comments. What are your thoughts?