Tesla Model S
John Goreham's picture

Why does the Tesla Model S catch fire in crashes but not Chevy Volt and Nissan Leaf?

The media is now asking why the Tesla Model S is making headlines about fires after crashes when much higher selling EVs are not.
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Tesla has been receiving a lot of unwanted attention lately because the Model S super sedan has had three fires in the past couple of months. Our coverage has been careful to point out that we do not think the vehicle is unsafe, or that the vehicle is more likely to catch fire than an internal combustion vehicle. However, there is one new question some are asking. That is “Why are the Chevy Volt and Nissan Leaf not catching fire after crashes, but three Tesla Model S cars have?”

In the three years since its inception, Chevy has sold more than 50,000 Volts in the US. According to Pam Fletcher, GM's Electrified Vehicles Engineering Chief, that adds up to about 300 million miles driven. She was recently asked if Chevy could offer the folks at Tesla any help. Please see video below. Regardless of what metric one chooses, the Chevy has about 3 times the amount of cars or miles driven than does the Tesla. Yet, in all that time nobody has ever caught one with its battery packs burning in a crash, or in a spontaneous event. The Volt did make news after the battery pack caught fire after a crash test. However, it was literally weeks after the test while the destroyed vehicle was in storage. A government investigation, as well as internal GM investigation led to some strengthening of the battery support compartment.

Our in-house Nissan expert, Aaron Turpen was asked about the Leaf for this story. He could not recall any Leaf fires after crashes being reported. Nor could our own internet search bring up any examples. Some have been burned in wildfires in Colorado, but the battery packs were not burned. The Nissan Leaf has outsold the Tesla Model S by a factor of three or more as well.

Up until this point Elon Musk, the Howard Hughes of electric cars, has usually defended his company vigorously, always referring to how much safer the Model S is compared to vehicles that use gasoline. We take no issue with his claims (although on the Tesla blog a mathematical sword fight has ensued). We do wonder though why the Volt and the Leaf are not having battery pack fires when they run things over or hit retaining walls.

One answer could be that the Tesla has waaay more battery than either the Volt of Leaf. The battery covering the entire bottom of the car just a few inches from the ground might be a significant reason. In the Tesla Model S that cannot be easily changed. Also, weight is not one of that car's strong points, so adding a big tough skid-plate is not an ideal solution. The car is also expensive, so a thin tough carbon fiber skid-plate addition is also not really an easy fix.

Reporters and the media are continuing to poke at Tesla’s three fires in five weeks. Regardless of whether the car is safe or not is usually not the focus of the story. The reputation of Tesla is now at stake and Tesla would be wise to look closely at the Audi and Toyota witch hunts of the past to see the inevitable outcome and adopt the best strategy it can to move past this issue. Continuing to say “Yes, our electric cars catch fire, but so do gasoline cars” may not keep working as comparisons to the Volt and Leaf start to be the angle of attack on the company.

Our accompanying photo of a Tesla Model S NOT on fire courtesy of the Tesla Website. Video courtesy of Youtube.com and the ChurchillClub


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Comments

So the Volt catches fire after being intentionally wrecked in a worst-case-scenario situation and after sitting for a few months in the weather. This teaches Volt owners that if they total their Volt including a rollover, they should not let the car sit in their driveway for a few months because it might catch fire. The Tesla Model S explodes into flames within minutes of running over debris on the road. This teaches Tesla owners that if they run over anything, they should stop, drop and roll. But Im sure that spunky lil Elon has an excuse for this.
I think the key factor here is ground clearance and battery pack placement. The S, as you mentioned, puts the pack along the floor and it is basically the entire floor, between frame rails, front to back on the car. The Volt puts the pack in vertically along the tunnel and the LEAF puts it flat, but dead center in the car rather than running the whole length. Obviously, for Tesla, there is not much choice given the huge number of cells required for the ranges they achieve, but it's an important point in terms of how likely damage is going to affect the pack.
Let me tell you the following: 1). The chemistry adopted by Tesla is extremely volatile, the battery cathode material actually decompose and release oxygen gas, the amount is more than a MM sized oxygen tank, the internal pressure and generation of oxygen explains the "ssssss" sound of the fiery fire. 2). The large battery battery and spread-out will make it prone to crush from all four directions, of course, no battery will catch fire once fully discharged, but when TEsla S is charged (even at 50%), it is a huge risk, no one vehicles is more prone to fire due to a crash. 3). The non-sese "our vehicle is safer" is just ridiculous, because vehicle fires usually come from very old vehicles, Tesla S is barely one-year old. 4). The battery system reliability will be poor due to >7000 18650, with years passing by, the chance of spontaneous fire will be dramatically higher! 5). Just wait for more fires to come in the next few months, oh, did I mention that fast charge within 20 min is another highly risky move? Just wait for cars to burn during recharge! Save my predictions, I suspect Tesla will not be around by the end of next Spring!
The Tesla Roadster has beenthe streets for over 5 years. Same size batteries with almost identical chemistry. No fires. ICE cars have a much higher rate of fire as they age because of rust and vibration begins to compromise structural integrity. Tesla uses aluminum and aerospace grade bolts and adhesive. Same as used at Mr Musk's SpaceX rocket company. Only time will tell regarding safety. So far so good. No deaths, No paralysis. No loss of limbs. No second or third degree burns.
Consider your comments saved here. Thanks for commenting.
There are serious concerns at Panasonic (they might stop selling to Tesla is they fear they might get involved in legal troubles) and other partners that Tesla will not survive the bad news, once asked to recall Tesla, they have no choice but to file bankruptcy! like Chapter 7, since the risk for them is so high!
Panasonic just agreed to sell Tesla an additional 1.8 Billion batteries over the next four years. Then Panasonic and Sumitomo Heavy Industries subsidiary Sumitomo Mining Co LTD of Japan have agreed to expand mining operations and battery production capacity to sell even more batteries to Tesla in four years time. If the batteries do not spontaneously combust I don't see how Panasonic can be held liable.
In a crash, I'd rather be in a car that warns you and shuts itself down than a Volt or a Leaf. Even the driver in Mexico that plowed his Model S through a wall and smashed into a tree walked away from the crash. The Tesla is designed to protect the driver, not itself. The fires caused by hitting road debris didn't spread into the passenger compartment, and both times, the drivers ignored the car's emergency warning. It is still the safest car on the road.
Excellent point. I did read that the most recent driver did follow the instructions and therefore was kept safe. Does seem a shame that a car north of $100K is susceptible to being totaled by road debris though. Thanks for commenting.
Well Aaron, how do you know that Volt or Leaf wouldn't warn a driver and shut themselves off? Where are you taking this knowledge from since none of them yet caught fire while on the road?
Good point Andrej. "Regular" cars all have automatic accident engine and fuel cutoff based on G load. All cars also have a "check engine" or more detailed light when the vehicle has suffered some kind of damage. Why do we credit the Tesla for telling the drivers it was disabled?
Because the Volt and Leaf are not electric cars. At the end of the day, they are still gas-powered cars that do not have the level of self-monitoring that the Model S has. A check engine light is not a fire alarm that shuts down the car. Their construction is not far removed from the rest of the Chevy and Nissan lineup, and the passenger cabin is not as well protected against catastrophic fire as the more expensive Tesla.
How do you figure a LEAF is not an electric car? It is powered only by electric. I'd think hat would qualify it as an electric car.
I was mistaken about the Leaf, but with a range of under 80 miles, how many are on the open road where road debris is more likely to strike the bottom of the car? I've got nothing against either car, but neither match the Tesla in terms of engineering safety.
Since you asked. About 40,000 LEAF's on the roads compared to 20,000 Tesla Model S's. LEAF hit the streets on Dec 2010, Model S Aug 2012. More LEAF's, been driving on the roads longer longer. It still raises the question why two debris fires for the Model S with none for the LEAF? Lower slung and higher speeds are my guess. BTW the Tesla fires are more of an insurance risk than a safety threat since the fires come after ample warning of impending doom for the vehicle.
I think that with regard to the Nissan Leaf you are mistaken. The Leaf is a "pure" EV, meaning it has not on-board gas engine. None standard. None optional. Good point though.
Not only is the Tesla Model S battery low slung under the vehicle, but the S Model has a nifty suspension system that lowers the car at highway speeds to improve the aerodynamics at those higher speeds. To me this explains why two of the recent fires have been highway fires, being very low to the ground makes the battery more prone to debris impacts than a Volt or LEAF which sit higher off the ground. I imagine the number of strikes and force of these strikes the Tesla receives is higher than for other EV's. If I were Tesla I'd fit a camera or radar at the front of the vehicle and use it for two purposes. 1. Input to a collision avoidance system like on some Fords. 2. To raise the suspension when road debris is detected ahead. Tesla could market the camera/radar as a new feature while quietly addressing the debris fire isues.
Thanks for adding the part about the highway ride lowering. I forgot to add that. Great idea about the camera, but on the highway with a truck behind and cars to the left and right, sometimes an item coming off the vehicle directly in front will be hit regardless of the technology. It seems a shame that such a pricey car is destroyed by a relatively common occurrence. Maybe instead of avoiding or lifting up, the car could instead drop the nose further to sort of scoop the object and take the impact on the bumper or on the front air dam. Sort of like a modern day cow catcher? Thanks for commenting.
You must be psychic. Tesla just announced a change to the ride height of the Model S on the highway.
If I'm not mistaken the batteries used by Tesla are Lithium Ion and the battery arrangement is liquid cooled. When Lithium is exposed to water it burns violently.
There was a lot of media attention hype and attention given to the three Tesla fires.....haven't been any more since then. Time reveals the truth....simple sensationalism journalism to sell more issues. And a lot of unprofessional people with negative comments...that have now been shown to be pure BS. Tesla is now rated as the SAFEST CAR EVER TESTED by the NHTSA. So, I hope this influences wanna-be competitors to make their designs safer. But I will bet the USA big Three will NOT do that. Every safety item from seat belts to airbags, to better bumpers to side beams in the doors had to be FORCED on the US companies by Congressional Legislation. Instead of bashing the one company making a really good product...these "critics" (expletives omitted) should rant against eh Big Three. PS, in case you don;t know...there are 200,000 gas car fires every year in America and numerous people die or are disfigured for life. Try bitching about that...instead of three fires in a Tesla with no injuries. Get a grip.
Great rant Donald. You know that Tesla had a recall following the fires and made structural changes to the Model S, right? The Model S was also the last vehicle in its price range to have forward collision prevention (FCP) and lane departure mitigation. If you have some specific vehicles the price, size, shape and weight of the Model S made by other manufacturers that are poorly rated for safety name them. Right now, Subaru has the highest safety ratings and also the most advanced FCP system in the U.S. market. Toyota follows and offers the most affordable TSP+ rated vehicle fleet. Anyone who follows vehicle safety knows that NHTSA is not the ranking system with the hardest testing, IIHS is. The first three model years of the Model S were not eligible for the top IIHS safety rating since they did not offer FCP. Vehicle safety is now being driven by IIHS and the automakers. The government can barely keep pace with the advances.