Zhang kenfeng, chenko, zhang jingyang
On the evening of 10 may, an electric bottled vehicle in an elevator in the town of zhanghua zhui district exploded, injuring many people, the smallest being a baby of only five months old. The video generated a high level of attention after its dissemination online。
Why did the electric bottle burn? How can we prevent a tragedy from happening? Journalists interviewed relevant experts on 11 november。
Expert: a variety of factors can cause a car to burn
On 10 may, there was a self-burning incident of electric bottling in 9 right-hand elevators of unit 1 in the chenghua district of chengdu. The surveillance video revealed that there were five people in the elevator at the time of the incident, a man holding an electric bottle car, the elevator closing instantaneously, the electric bottle car setting fire, the elevator being packed with smoke, and five seriously injured, including a baby。
The chonghua district emergency management authority subsequently released information that, on 10 may 2021, at approximately 1935 hours, there was a burning of electric bottling vehicles in nine units of elevator no. 1, located in the 8-crub-tree neighbourhood of chu jiaqing, and that the government team in longgang had dispatched two vehicles, 10 persons, for disposal and that the fire had been extinguished at around 1950 hours. At present, the cause of the fire has been tentatively identified as a fire on the electric bottling vehicle, and further investigations are under way in chenghua district. As of the morning of 11 may, journalists had learned that three persons injured in the accident had received moderate burns, and that one elderly person and five-month-old babies were suffering severe burns, which were being treated at sichuan university's wahshi hospital。
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Where is the fire on the electric car? According to liu chang guo, one of our first developers of power lithium batteries and chief engineer of sichuan energy-based technology ltd., liu chang guo, due to the high energy density and high activity of the lithium batteries of the tri-channel material, in recent years, most of the vehicles in which fires and explosions have occurred, whether in electric cars or on electric bicycles, have been using lithium batteries of the tri-channel material。
However, when the battery is used for two years or more, the electrolyte in the battery is ageing to varying degrees, producing flammable gases internally, and the electrolyte itself is flammable, and safety risks arise。
In general, fire explosions in vehicle batteries during charging power can be summarized as follows:
The first is that the battery has a long life and, generally speaking, more than three years of use, the battery is ageing, the consistency of the internal material is decreasing, leading to overcharges and uncontrolled self-management of the inside material of the battery. Second, there are many soft packagings and square batteries, which are used for two years or more, resulting in internal damage to the sei membrane (membrane of a positive or negative cell) which produces gaseous or anaesthesia and eventually leads to short circuits for batteries. According to wang qin, general secretary of the emergency and rescue centre of the central oil field, which has been engaged in several years of fire and emergency safety work, since the body of electric vehicles is mostly flammable material, it is difficult for people to escape and is highly vulnerable to casualties, as the fire caused by electric bottlings has been the focus of attention in recent years in the field of fire safety, since the body of electric vehicles is mostly flammable material, and when fires start, the rate of combustion is high, and the amount of toxic fumes is produced。
He states that the specific reasons for the fire involved various aspects of the circuits, batteries and bottles, and chargers. Fires can be caused by overloading, such as the private replacement of vehicle circuits, the private loading of electrical equipment, modifications or replacement of components, and by excessive charging due to the ageing of the cylinders, the private replacement of large-capacity batteries or the mixing of different batteries, resulting in power flow imbalances between batteries。
“in addition, chargers are important aspects. If chargers do not qualify, they cannot be out of power in a timely manner or overloaded after they are charged, which can cause overcharges to cause fires; the chargers do not match the battery parameter type, resulting in excessive voltage during charge-making, severe water loss of the battery and high temperatures。
Call the alarm to regulate the use of the bottled car
“despite the specific cause of the explosion that caused the electric bottling, a specific investigation is pending. But there is no doubt that this incident used a safe alarm for the electric bottler.” wang qing gin said that, with the increase in the number of users of electric bottling in our country, the topic of electric safety in electric bottling was of great concern。
“in case of use of a battery, no private changes to the battery and circuit of the vehicle. When charged, the `fly line' chargers, such as temporary wires, should be eliminated, as far as possible, the environment should be chosen for charging, with the appropriate safety distance between the electric bottling vehicles, between the electric bottling vehicles and the charging facilities, and with the avoidance of charging in special conditions such as sun, heat and rain.” he said。
Wang qingxiang said that electric bottling should be regularly maintained and inspected by professional means of maintenance, such as correcting battery imbalances, water shortages, etc. “at the same time, attention should be paid to the fact that batteries should not be used for extended periods of time, which can create risks such as the ageing of batteries and insulation failures. The electric bottling vehicle, after a long period of use, will lead to problems such as the ageing of the circuits and the release of some interfaces, and should also be fully inspected and maintained at the regular maintenance point in time.”
In the same vein, liu chang guo indicated that users of electric vehicles must use batteries in accordance with the protocol, avoiding all charges and usages prohibited by the book. At the same time, after two years of car battery use, at least once a year battery safety check is performed to prevent a risk。
In addition, with regard to improving battery safety, liu chang guo said that progress in vehicle battery technology and market development must, of course, pursue battery energy density and vehicle mileage, but that in order to achieve both increased mileage and the elimination of safety hazards, security must always be placed at the top of the list, with a focus on a combination of materials, principles and assembly. “improved battery safety is a system engineering project that covers the entire process of product design, material development, charging and use.” “as far as we are concerned, the growth of our car-powered batteries is large and weak and lags behind that of the automobile industry, so i personally propose to increase research and development in terms of materials, and to put it at the heart of the real technology — positive and negative poles and electrolytic poles — with a fundamental shift in the entire industry only if there is revolutionary progress in the storage of energy materials.”
In relation to the incident, the question of how the electric bottler could enter the elevator room. As early as december 2017, the ministry of public security of the people's republic of china issued a circular on the regulation of electric vehicle parking and charging to enhance fire prevention, stating that, in order to regulate electric vehicle parking and charging, electric vehicles should be placed in a secure location, that they should be charged in such a way as to ensure security, and that public areas such as common access roads, stairwells and safe exits within buildings should be strictly prohibited from parking or charging electric vehicles。
In may 2018, the security committee of the state council held a videoconference on integrated management of fire safety on electric bicycles. It was also proposed that the private adaptation and dismantling of spare parts of the original plant, the private removal of critical components such as speed limiters, and the private replacement of large power batteries, should be strictly prohibited; and that efforts should be made to address the root causes of the problem of electric bicycles, such as “into-house” “to-house” “to-house” and to cut off the “link” of fires。
