Recently, a pure electric bus in Harbin caught fire while charging in an open-air garage. The Fire accident recognition of the Fire Rescue Brigade determined that the cause of the fire was that the heating system of the power battery was abnormal and the temperature in the battery bag continued to rise during the charging process of the vehicle, which led to the burning of the vehicle.
Since the advent of new energy vehicles, the issues of "charging" and "safety" have been the focus of people's attention. You know, the ambient temperature of power battery charging is 0 °C-45 °C, and the optimum ambient temperature is 25 °C, which is impossible to achieve in winter. Especially in the low temperature climate of northern cities, the charging problem of new energy vehicles becomes particularly thorny.
To solve the problem of charging new energy vehicles in winter, the principle is to increase the temperature of the power battery. However, in this process, the brand new energy bus caught fire due to the abnormal heating system of the power battery.
"there are tigers in the front and pursuers in the rear." For a while, how to solve the problem of "low temperature charging" and "safety" of batteries has become a major problem perplexing the operation of new energy buses in northern cities in winter.
Of course, not all batteries have pain points of decay and slow charging in extreme cold or winter. According to Xiao, the bus driver and station chief of Harbin Futong bus Transport Co., Ltd., "it is more durable than traditional batteries. Buses with other batteries used last winter froze more than 30 cars in one night, but there was nothing wrong with Yinlong cars." you can still leave on time the next day. "
Some people in the industry said, "the vehicle can be charged and discharged normally from 50 ℃ below zero to 60 ℃ above zero to ensure the normal operation of the vehicle at low temperature." Yinlong lithium titanate battery is much better than other batteries in the market in terms of temperature resistance, and the power attenuation is almost negligible under extremely cold conditions. "
The reason why the lithium titanate power battery can withstand wide temperature is that the lithium titanate structure is stable, its spinel structure has a three-dimensional lithium ion diffusion channel, and the surface does not form a solid-liquid interface passive film. The kinetic properties at low temperature can still be maintained at room temperature, and charging will not lead to short circuit or lithium dendrites that worsen the negative electrode.
In fact, in recent years, many people in the industry and consumers have turned their attention to lithium titanate batteries and placed high hopes on them. The author believes that when the ultra-low temperature resistant power battery represented by Yinlong lithium titanate is used in new energy vehicles in the extremely cold areas of the north, there is no need to add "power battery heating system". It is not only to put an end to the safety hidden dangers caused by the power battery heating system from the source, but also to really solve the problem of new energy vehicles catching fire.
The hidden danger of safety has always been a topic of concern and concern for the industry and consumers, and it is also a "life door" for the new energy vehicle industry to break through and solve.
There is a fire of "abnormal heating system of power battery" in winter, and safety accidents such as "spontaneous combustion" and explosion occur one after another in summer. Some spontaneous combustion vehicles not only affect themselves, but also affect the vehicles next to them. To a certain extent, safety has become the death of new energy vehicles.
Ouyang Minggao, academician of the Chinese Academy of Sciences and vice president of the China Electric vehicle Association, said, "Battery safety technology is the first focus of the revolutionary breakthrough in battery technology and the first key to the performance upgrading of pure electric vehicles. It is also the lifeline of the sustainable development of electric vehicles. The research and development of power battery should take safety as the core and make every effort to improve the safety technology of the existing lithium-ion battery system. "
Compared with graphite anode material, Yinlong lithium titanate, which is called "zero strain material", hardly forms a SEI film with poor stability, which avoids the loss of control caused by the decomposition and regeneration of SEI film under extreme conditions, and greatly reduces the hidden danger of battery fire and explosion. At the same time, lithium titanate material has higher potential to lithium metal, which avoids the formation of lithium dendrite in the process of overcharge and has better safety and stability.
It is worth noting that on May 12, three mandatory national standards, including "Safety requirements for Electric vehicles", "Safety requirements for Electric buses" and "Safety requirements for Power batteries for Electric vehicles", will be implemented on January 1, 2021. This is the first batch of compulsory standards in the field of electric vehicles in China. It is not difficult to predict that in the field of electric vehicles, battery safety will be paid more and more attention, and manufacturers will invest more resources to tackle key problems to ensure the benign and orderly development of China's new energy vehicle industry.
