21700 battery

　　The source of spontaneous combustion in new energy vehicles is mostly 21700 battery, and there is still room for upgrading technical standards.

　　As one of the most influential new energy vehicle brands in the world, Tesla has been regarded as a target for learning and catching up by many car brands. Nowadays, with the frequent occurrence of spontaneous combustion incidents, whether Tesla cars and even electric cars are safe has become a topic of concern to many people.

　　Although no one doubts that electrification is an unstoppable trend in the development of the global automobile industry. However, the recent frequent spontaneous combustion accidents have once again pushed new energy vehicles to the forefront of public opinion.

　　On April 21, a Tesla Model S spontaneously ignited in Shanghai. According to on-site surveillance video, the Tesla Model S parked in the underground garage suddenly caught fire and ignited several vehicles nearby. Users of the building were also arranged to evacuate, causing heavy losses.

　　On May 12, a Tesla Model S spontaneously ignited half an hour after it was parked at San Po Kong Plaza in Hong Kong. There were three explosions during the combustion process. It took firefighters 45 minutes to extinguish the fire.

　　According to reporters, in just two months, Tesla's electric vehicles have experienced four spontaneous combustion incidents around the world. As one of the most influential new energy vehicle brands in the world, Tesla has been regarded as a target for learning and catching up by many car brands. Nowadays, with the frequent occurrence of spontaneous combustion incidents, whether Tesla cars and even electric cars are safe has become a topic of concern to many people.

　　Recently, reporters interviewed a number of industry experts and scholars on whether new energy vehicles are safe, how to deal with spontaneous combustion accidents, and what improvements and upgrades are needed in the development of new energy vehicles to find the problems and solutions behind the spontaneous combustion of electric vehicles. .

　　After dismantling it, I saw that among the entire Tesla battery module (a total of 16 modules), only four modules near the front of the car were burned out. The remaining 12 modules have not yet been affected. If the fire is extinguished later, more lithium-ion battery modules (the source of powerful deflagration) may be affected and deflagrate... After the Tesla Model S spontaneously ignited, the owner, Mr. Dong, had not slept a wink for more than 30 hours. In addition to fear and anger, the biggest question in his mind is: Why does a vehicle bought at a high price spontaneously ignite under static conditions?

　　The incident is currently under investigation and no preliminary determination or conclusion has been formed. We will actively cooperate with the investigation and announce the investigation results in a timely manner. Please do not spread or believe rumors. Three days after the Tesla Model S spontaneously ignited, Tesla announced on its official Weibo.

　　Although Tesla has not yet given an official investigation conclusion, after the Tesla Model S spontaneously ignited, Shanghai fire scene experts, judicial experts, and automobile experts rushed to the scene for investigation as soon as possible. Tao Wei, an expert on vehicle defect investigation and identification and recall from the General Administration of Quality Supervision, Inspection and Quarantine, said that at present, the cause of the Tesla Model S fire is a battery short circuit, and identification will continue in the future.

　　In fact, it is not the first time that new energy vehicles, especially pure electric vehicles, have spontaneous combustion. According to incomplete statistics, there were more than 40 electric vehicle fire incidents across the country in 2018, and the vehicles covered different models such as passenger cars, buses, and logistics vehicles. In Shenzhen alone, eight spontaneous combustion accidents of new energy logistics vehicles occurred.

　　According to Liu Zhichao, an analyst in the automotive industry, there are many and complex reasons for spontaneous combustion of lithium-ion battery manufacturers for electric vehicles, but the most important thing is the battery problem. For example, an internal short circuit in the battery is one of the common causes. For example, when the car is vibrating, the material coating the positive and negative electrodes of the battery plate falls off, resulting in a short circuit in the battery. This kind of internal short circuit in the battery is difficult to control and may induce spontaneous combustion.

　　In addition, Liu Zhichao pointed out that the loose connection of the battery and poor external contact, or the battery is overcharged or overdischarged, may cause the internal temperature of the battery to rise and cause spontaneous combustion. Since there is a process for the temperature to rise to spontaneous combustion, like this Tesla car, the lithium-ion battery will catch fire if it is parked in the basement without charging or driving.

　　Big data confirms the view that the source of spontaneous combustion of new energy vehicles is mostly the battery. The Qianzhan Industry Research Institute analyzed and counted fire accidents of new energy vehicles since 2017 and found that among the causes of fire accidents, spontaneous combustion of power lithium batteries accounted for 31%, mainly due to the internal or external short circuit of the lithium-ion battery. The battery releases a large amount of heat in a short period of time, and the temperature rises sharply, leading to thermal runaway.

　　Unscientific cost requirements have added new safety hazards. In recent years, the popular practices in the battery industry such as simplified system design and increased capacity and volume of single cells have added new safety hazards to batteries. Liu Zhichao bluntly said that taking Tesla as an example, in order to reduce weight and cost, Tesla eliminated the outermost insulation layer of the battery, which further deepened the risk.

　　It’s not just car companies that need help from many parties for the safe development of electric vehicles.

　　Regardless of changes in external use and environmental issues, the cause of heating is also closely related to its own manufacturing materials and processes. Problems such as excessive battery use, uneven battery pack temperature, short circuit, etc. may lead to thermal runaway.

　　If you want to reduce or even avoid the occurrence of spontaneous combustion incidents of new energy vehicles, you must first strictly control the technology at the technical level. Sun Fengchun, an academician of the Chinese Academy of Engineering and an expert on new energy vehicles, said that from a technical point of view, there are two routes to solve the fire problem of electric vehicles. The first is to use pure solid electrolytes, but it is difficult to implement in a short time; the second is to develop absolutely safe electrolytes. Control System.

　　my country's new energy vehicle policy orientation has always encouraged high energy density in the past. In order to meet the requirements, car companies have obtained more subsidies and rapidly improved this indicator. But now many car companies will also pay attention to safety factors, such as re-selecting lithium iron phosphate batteries. he introduced.

　　In addition to strictly controlling the production process and making technological breakthroughs, mastering certain escape methods is also an important means to protect safety in the event of vehicle spontaneous combustion.

　　If you are around the vehicle when it spontaneously ignites, you must stay away from the spontaneously igniting vehicle as soon as possible. Pure electric vehicles spontaneously ignite very quickly, especially when the battery pack is short-circuited, deflagration and other phenomena may occur within tens of seconds. Tao Wei reminded that on the premise of ensuring that you are in a safe environment, call the police as soon as possible, and then contact the insurance company and relevant brand 4S stores to assist on the scene. Overall, safety comes first.

　　The frequent spontaneous combustion accidents of electric vehicles have not only attracted public attention on the safety issues of new energy vehicles, but the distribution of accident liability and compensation handling have also become hot topics in the industry.

　　Take the Shanghai Tesla Model S spontaneous combustion accident as an example. The cause of the Tesla Model S spontaneous combustion accident has been preliminarily determined to be caused by a battery short circuit problem, and it can basically be characterized as spontaneous combustion. If Tesla owners do not purchase spontaneous combustion insurance, the insurance company will deny compensation. Yang Liang, a lawyer at Dacheng Law Firm, told reporters that car owners can only insure vehicle spontaneous combustion insurance on the basis of motor vehicle loss insurance.

　　Therefore, Yang Liang suggested that if the owner of a Tesla Model S spontaneous combustion accident did not purchase spontaneous combustion insurance, the lithium-ion battery can defend its rights against the seller on the grounds that the new energy vehicle has quality defects. The seller shall be responsible for repair, replacement or return and compensation for losses. If the manufacturer is responsible, the seller shall recover compensation from the manufacturer and supplier.

　　In fact, compared with the fuel vehicles that have been developed for more than 100 years, the development time of new energy vehicles is short and the development speed is fast. This has also caused the problem that relevant laws and regulations are not yet complete to a certain extent.

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