Electric vehicles (BEVs) are selling better and better, but as ownership has grown, there have been more and more reports of BEV fires.
Despite the emergence of various battery safety technologies, so far, no pure electric vehicle manufacturer has dared to pat their chests to ensure that "our batteries will never catch fire."
What is particularly frightening is that electric vehicles often catch fires without warning, and there is no warning in advance, leaving a short time for the people on the car to escape, from smoke to burning, often only a few minutes.
Since the beginning of this year, there have been significantly more reports of BEV fires than in previous years, and almost all major brands have been involved.
Musk once said that "the spontaneous combustion of fuel vehicles is more than 5 times that of Tesla and other electric vehicles", but this is obviously inconsistent with the facts, according to the data given by the Fire and Rescue Bureau of the Ministry of Emergency Management, there were 640 new energy vehicle fires reported in the first quarter of this year, up 32% year-on-year, higher than the average increase of 8.8% of vehicle fires, and there were more than 7 new energy vehicles on average every day.
Fires are fast and difficult to extinguish
The vehicle state of BEV fire is generally divided into driving, parking, charging and collision, etc., of which parking and charging fire account for the largest proportion, the main reason is the battery thermal runaway.
The most recent reported spontaneous charging accident was at 14:15 on April 21, when a charging Yundu electric vehicle caught fire in the parking lot of Tianjiuwan Market in Zhenhai Street, Licheng District, Putian City, Fujian Province.
Although someone tried to extinguish the fire with a fire extinguisher, it did not work at all, but it burned more and more severely, and also ignited an electric car that was charging next to it. Finally, firefighters arrived and it took more than an hour to extinguish the fire. It is worth noting that the brand's electric vehicle fires have occurred at least four times this year, and the brand is currently in a state of suspension.
Charging stations, parking lots are often electric vehicle fire high incidence area, these places of spontaneous combustion accidents are easy to affect the next vehicle, April 18, a charging station in Haikou a Weima pure electric vehicle suddenly spontaneous combustion, fortunately next to the taxi driver reacted quickly, timely unplugged charging plug, quickly drove the vehicle away, only to escape a disaster. Reports of spontaneous combustion of the brand BEV have been reported at least 3 times this year.
In addition to the fire caused by the battery's own failure, chassis bumping during driving is also one of the important reasons for battery fire.
At 20:00 on April 22, a Chang'an new energy vehicle caught fire at the entrance of an underground garage in Hangzhou. The cause of the fire, according to the owner of the car said that the chassis in the driving rubbed into the manhole cover at the garage entrance, the owner of the car to check when he heard the bottom of the car made a "clanging" sound, after a while it burned up.
The chassis of pure electric vehicles is generally lower than that of fuel vehicles, and the risk of supporting the bottom and scratching is also higher.
The power battery is large and heavy, most of the pure electric vehicle models are installed in the chassis position of the power battery, because the battery pack has thickness, and can not sacrifice the internal space, so the ground clearance of the BEV is generally lower than the fuel vehicle, so the risk of the chassis scratching is also greatly increased.
Some brands have launched electric off-road vehicles, but the battery does not do special protection, and it is inevitable to support the bottom and scratch during off-road, resulting in damage to the battery pack and causing a thermal runaway fire.
BMS electronic control system mismatches can also lead to thermal runaway batteries. Euler electric vehicles have been blacklisted by some charging stations because of frequent fires during charging. Although Euler has also carried out a recall to update the BMS and battery modules, it does not seem to solve the problem. On April 6, an Euler caught fire and exploded at a charging station in Nanning, which was once again on the hot search.
On March 17, after an open fire was extinguished outside, a pure electric vehicle in Haikou revived the power battery when the body was flipped.
Because the battery cell is in the battery pack, even if the external open flame is extinguished, the internal battery cell may still be burning, so after the surface open flame is extinguished, the firefighters must continue to cool down or even dismantle the battery to avoid re-ignition. Therefore, without professional fire extinguishing means, it is almost impossible to extinguish the battery fire, and you can only watch the vehicle being burned into a pile of scrap iron.
Firefighters remind consumers: in case of an electric vehicle on fire, keep calm and do not panic, stay away from the scene for the first time, dial 119, and wait for the firefighters to deal with it.
On February 16, a cargo ship carrying 3,965 vehicles of volkswagen, Porsche, Audi, Bentley and Lamborghini from the German port of Emden to rhode island in the United States caught fire for about two weeks, and finally sank near the Portuguese Azores.
As for the cause of the fire, the Portuguese Navy said that although there is no conclusive evidence at present, there is reason to suspect that the lithium batteries of the ship's electric vehicles caused the fire. According to foreign media Imaginfo, the model that caught fire may be an Audi e-tron Sportbacks, and the combustion of power batteries makes the rescue work more difficult.
According to an institutional analysis, the value of cars and trucks on the cargo ship is $401 million, and the total value of the ship, including this ship, is estimated at $438 million. This is perhaps the biggest loss caused by an electric vehicle fire in history.
The deflagration after the BEV collision was very deadly
Collisions are of course also a big reason for BEV fires. In July last year, a NIO EC6 hit a stone pier, the vehicle was seriously damaged and caught fire, and the owner of the car was unfortunately killed.
The recent accident in Dalian that caught fire after a Tesla collision is also unsettling. At noon on April 18, at the intersection of Shengli Road and Lianhe Road in Dalian, a Tesla Model 3 collided with a Citroen Elysée, trapping the co-pilot passenger. Fortunately, the enthusiastic masses passing by shot in time, when some people picked the door with their bare hands, some people elbowed the window glass, but to no avail, and finally a sanitation worker brought an iron rod to successfully break the window and rescue the co-driver passengers.
According to the recollection of the rescue personnel at the scene, 30 seconds after the rescue of the person, the vehicle began to burn, if it is a little later, the consequences are unimaginable.
The Model 3 didn't catch fire after the crash test, but no safety test could cover all real-world scenarios.
Judging from the scene video of this accident, it is roughly equivalent to the front of C-NCAP 50% overlapping movement progressive deformation barrier collision, similar collision results of the two major domestic crash test agencies C-NCAP and C-IASI have regulations: within 30 minutes after the end of the collision, REESS (rechargeable energy storage system) should not explode, fire, otherwise it is unsafe.
The Tesla Model 3 was excellent in the 2020 C-IASI crash assessment, but this time it still caught fire in a short period of time, so the results of any safety tests cannot be trusted.
Another big surprise is that the Model 3 door did not automatically unlock after the collision occurred!
After a collision, the doors are automatically unlocked, which is a basic requirement for today's cars. After the collision, there may be a critical situation such as the driver's coma and the vehicle catching fire, and if the rescuer cannot open the door from the outside of the car in time, it will delay the best rescue time.
Why the fire after the collision, why the car door can not be opened, Tesla should give the public an explanation, but as of press time, Tesla has not had any official statement about the accident.
THE CAUSES OF BEV FIRE ARE DIVERSIFIED, THE BATTERY ITSELF IS AGING, EXTERNAL COLLISIONS, EXTREME TEMPERATURES, ELECTRONIC CONTROL SYSTEMS, HIGH LOADS OF OPERATING VEHICLES, ETC. MAY LEAD TO THE THERMAL RUNAWAY FIRE OF THE BATTERY, OUYANG Minggao, ACADEMICIAN OF THE CHINESE ACADEMY OF SCIENCES, BELIEVES THAT HIGH-POWER FAST CHARGING IS AN IMPORTANT CAUSE OF ELECTRIC VEHICLE FIRE.
Tesla V3 charging pile maximum charging power of 250kW, but this fast charging should be only auxiliary, daily should also be based on slow charging.
Academician Ouyang's team found that the stability of the power battery will deteriorate significantly after 300-500 times of fast charging, and the thermal runaway temperature of the new battery is generally 215 degrees Celsius, while the thermal runaway critical point of the battery that uses fast charging is greatly reduced to 107 degrees Celsius.
Based on the general household BEV charging 300 times, each time the actual driving of 400 kilometers, now the BEV on the market travels about 120,000 kilometers, will face a sharp decline in the critical point of thermal runaway, the probability of spontaneous combustion rises sharply.
At the same time, in order to pursue longer battery life, manufacturers are getting bigger and bigger; in order to shorten the charging time, the power of the charging pile is also getting bigger and bigger, and naturally, the hidden dangers of battery safety are getting bigger and bigger.
Statement | Kano
(This article is the author's personal opinion only and does not represent the position of DearAuto.) )
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Mr. Li Guoyong of Guangdong Green Law Firm