RCCN WeChat QrCode
Mobile WebSiteOn the evening of April 21, a fire broke out in an underground garage in a residential area in Shanghai. The cause was a self-ignition of a Tesla Model S parked in a ground floor garage and quickly ignited surrounding vehicles. The fire brigade then sent 15 fire engines for nearly an hour before the fire was extinguished. However, the incident has caused almost all the other cars on the basement floor to be burned, and the cars on the second floor of the ground were completely flooded by fire sprinklers.
Less than 24 hours after the Tesla spontaneous combustion incident, it was claimed that there was an accident with the Tesla car of Tesla. On the afternoon of April 22, a Weilai ES8 in Xi'an suddenly caught fire when it was repaired at the authorized service center. Wei Lai issued a notice saying that the investigation of the cause of the fire has been opened and the results of the investigation will be announced in a timely manner. Judging from the time of the incident and the content of the announcement, this time, Weilai did indeed "tender" Tesla.
In recent years, it has never been rare for new energy vehicles to catch fire. On August 25, 2018, a Weimar EX5 electric vehicle in the Weimar Automobile Research Institute in Chengdu suddenly caught fire and spontaneously ignited. In fact, not only is the new force of building a car, but the old electric vehicle manufacturer BYD also burned the car. In August of the same year, at the Shanghai Hongqiao Railway Station, a hybrid electric-powered BYD Song SUV also spontaneously ignited. In addition, Beiqi New Energy, Nissan, Jiangling and other brand products have had similar accidents.
From August to September 2018, it is the eventful season for new energy vehicles. In this more than a month, electric vehicles have been on fire for as many as 12 times. According to informed sources, the actual number of incidents occurred in the past was much more than that disclosed.
So, the question is: Why do new energy vehicles always burn? Why is the burning so fierce?
Why are the consequences of the spontaneous combustion of electric vehicles so serious?
Take the example of the Tesla Model S that is “causing trouble”. The Model S has a battery capacity of 85 kWh, and the battery pack is made up of 16 battery packs in series, and each battery pack consists of 444 lithium batteries, which are formed in parallel at 74 knots. Calculated, the vehicle's power battery pack consists of 7104 lithium batteries, with an average lithium battery capacity of 12Wh. This is converted into energy units of 43kJ, which is equivalent to 100g TNT. Although this is the energy released by the lithium battery after its complete electrochemical reaction, it does not burst out like an explosive, but it is enough to cause considerable damage.
In addition, Tesla uses a ternary lithium battery for energy density, and its electrolyte burns a large amount of toxic and combustible gases such as carbon monoxide, toluene and hydrogen sulfide. At the same time, oxygen combustion is also generated during the reaction process, which makes the electric car fire often burst in an instant, and the fire rapidly expands. Due to the generation of oxygen, it is difficult to use traditional fire-fighting methods such as air separation, carbon dioxide spraying and dry powder. Firefighters can only use a large amount of water to cool down the fire. Therefore, the electric car is often on fire because of the unsuccessful rescue, resulting in irreparable damage. Put it in the underground garage, which also affects the B2 floor owners who were originally unrelated.
The reason why the electric car battery is on fire
The brands and products of the fire are different, but the cause of the fire is very similar. The most common cause is the internal short circuit of the battery. When the positive and negative terminals of the battery are short-circuited, the instantaneous current exceeds 5A and a large amount of heat is generated, which can cause the short-circuited part to reach a very high temperature and cause the battery to ignite. For the cause of the short circuit, there is no paper on the battery core, the paper is damaged, the protection plate is unstable, and the diaphragm inside the battery core is unstable. The causes of these problems are external collisions and line aging.
In addition, traffic accidents are also an important cause of spontaneous combustion of batteries. What is disturbing is that the current power battery packs on the market are generally not able to pass the needle test. In fact, the relevant experts have called for a long time, and the acupuncture test has not become the industry-wide mandatory standard because its difficulty is too high, which is one of the biggest safety hazards of electric vehicles.
Who will pay for the loss of self-ignition of electric vehicles?
As far as this Tesla spontaneous combustion incident is concerned, although the official has not yet given the results of the investigation, according to informed sources, the fire incident is likely caused by the private wiring of the owner. If this is the case, all losses caused by the fire will be borne by the owner himself.
But for this incident, is Tesla really able to stay out of the way? In fact, all electric vehicle companies, including Tesla, provided a charging gun and did not specify the charging of the owner's wiring. For example, how many meters does the owner's "flying line" length control? How many hours does the charging time need to be controlled? What standards do cables need to meet?
In fact, this information is often not delivered to the owner of the vehicle when the vehicle is delivered, and even some merchants will provide the wiring proactively. Is there any dereliction of duty in the process? Does the merchant need to give compensation after the event? Still to be considered. Nowadays, the domestic charging infrastructure is not perfect enough. There is no relevant specification for charging electric vehicles. The majority of electric vehicle owners will still choose the way of wiring charging for a long time. How to solve the hidden problems, further exploration is needed.
