The Ministry of industry and information technology issued a notice on the investigation of potential safety hazards of new energy vehicles, requiring new energy vehicle manufacturers and power battery suppliers to complete the investigation of potential safety hazards of new energy vehicles before the end of October this year.
Safety has always been the focus of new energy vehicles. Since May, several spontaneous combustion incidents of new energy vehicles have happened continuously, which once again focused the attention of the market on the safety of new energy vehicles. In fact, as the core of the safety of new energy vehicles, the safety technology of power battery has been continuously upgraded, and has shifted from single safety to system safety, constantly "thickening" the safety bottom line of new energy vehicles.
Focus on power battery
It is understood that this investigation, which is called "the most stringent in history" by the industry, focuses on the safety hazard investigation of sold vehicles, waterproof protection of inventory vehicles, high-voltage wiring harness, vehicle collision, on-board power battery, on-board charging device, battery box, mechanical parts and vulnerable parts, and takes effective technical measures to reduce the risk of vehicle fire according to the actual situation of vehicles.
According to the inspection reference table released by the Ministry of industry and information technology of the people's Republic of China for safety investigation of new energy vehicles, the main content of the safety hazard investigation is the power battery part, which includes appearance inspection, software diagnosis, air tightness test, unpacking inspection and replacement.
In fact, since the beginning of May, the policy level has been increasing in the safety of new energy vehicles. In early May, the Ministry of industry and information technology officially issued three mandatory national standards, namely, safety requirements for power batteries for electric vehicles, safety requirements for electric vehicles and safety requirements for electric buses, which will be implemented from January 1, 2021.
It is understood that these three mandatory standards are based on China's original recommended national standards and are in full line with the United Nations Global Technical Regulations on electric vehicle safety, which is led by China. They further improve and optimize the safety technical requirements for electric vehicle and power battery products.
On May 26, the Ministry of industry and information technology held a special meeting to strengthen the implementation of national standards for new energy vehicles, requiring all new energy vehicle products to comply with national standards.
These policies emphasize the safety of power batteries for new energy vehicles most prominently. While optimizing the safety requirements of battery cell and module, the requirements of thermal safety, mechanical safety, electrical safety and functional safety of battery system are strengthened. The test items include system thermal diffusion, external fire, mechanical shock, simulated collision, damp heat cycle, vibration soaking in water, external short circuit, over temperature and over charge, etc.
Battery safety continues to upgrade
Aiming at the problem of battery safety, new energy vehicle manufacturers and battery manufacturers have been constantly exploring and trying to improve the safety of vehicle power batteries through different technical routes and different products.
At present, lithium iron phosphate battery and ternary battery are the mainstream in the field of power battery, and others such as lithium titanate and lithium manganate also have certain applications. Some new system batteries, including solid-state battery, magnesium battery, cobalt free battery, hydrogen fuel cell and so on, are also in the research and development or exploration stage.
Technical route is the common choice of market and users. Due to the wide application fields and many application scenarios of new energy vehicles, the demand for power batteries is also diversified. Iron lithium battery is the characteristic of our country, which has the characteristics of high safety and long life. It is mainly used in the field of electric bus, logistics vehicle and other commercial vehicles. The high energy density of ternary battery can effectively solve the mileage anxiety of private car users, and it has become the mainstream solution of new energy passenger cars in the world.
Because of this, many vehicle enterprises and battery manufacturers basically maintain the state of parallel progress of various technical routes. While large quantities of iron lithium batteries and ternary batteries are put into the market, the pre research and technical reserve of other technical routes are carried out at the same time. Taking Ningde times, which has the highest market share of vehicle power battery in China, as an example, the production and sales of ternary battery and iron lithium battery are in the forefront of the industry, and maintain the technical advantages of other battery technology routes.
With the continuous increase of R & D investment, various battery technology routes are constantly upgrading to make up for the shortcomings. In view of the weakness of low energy density of iron lithium battery, BYD has launched blade battery, which greatly improves the energy of iron lithium battery with the same volume through structural changes. Aiming at the problem of low stability of ternary battery, Ningde times has created the "controlled short circuit" safety technology after years of research and development. In the case that the ternary battery is penetrated or impacted violently by external metal foreign bodies such as acupuncture, the internal short circuit of high current will not occur, so that the thermal runaway of the battery will not be caused.
In 2017, Ningde times took the lead in tackling the problem of high-energy density ternary battery needling in the world in response to the requirements of a European car company for high-energy density ternary battery cell technology that can pass the needling test, and sent it to Rhine TUV testing and certification by customers. The results of the report show that in the acupuncture experiment, the ternary battery can achieve no fire and no explosion, and the battery temperature is only 35.1 ℃.
The latest news of Ningde times shows that it has developed a battery with a service life of 16 years and a driving distance of 2 million km, which can be put into the market at any time, and the price is only about 10% higher than the current battery of electric vehicles. At present, the mileage of batteries used in general electric vehicles is only about 240000 km, and the service life is only eight years.
With the continuous improvement of battery technology of domestic enterprises, more and more international brands begin to choose domestic batteries. At present, Ningde times has reached a cooperation with Tesla to provide batteries for model 3 cars produced in its Shanghai factory. In addition, Ningde times has been cooperating with BMW, Audi and Porsche.