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"No fire" will be the safe fresh air direction of battery

2020-12-11 11:06:54 0

Recently, it is reported that Huawei, which has entered the field of automotive intelligent networking, has clearly adopted ternary lithium battery as the new energy technology direction of intelligent vehicles. Like Tesla's battery technology route selection for high-end model 3 and model y models, Huawei also believes that ternary battery will be the mainstream technology route for medium and high-end passenger cars at present and even in the future.

Compared with lithium iron phosphate battery, ternary battery has higher energy density, stronger charge discharge rate performance, and better wide temperature resistance. In view of the long endurance and intelligent demand of electric vehicles, domestic and foreign well-known electric vehicle models currently take ternary as the mainstream technical route.

However, the ternary battery is not perfect, among which the most prominent is the safety "disadvantage" compared with lithium iron phosphate battery. According to the data, up to now, the fire accident rate of new energy vehicles equipped with ternary batteries and lithium iron phosphate batteries has dropped to 0.24% and 0.09% respectively this year. However, it can be seen that the ternary battery is still a little "high burning" compared with the iron lithium battery.

Obviously, if anyone can solve the security problem of ternary battery in advance and mass produce "non fire" ternary battery, then who is likely to win the favor of domestic and foreign mainstream automobile enterprises in this round of competition.

Recently, xinwanda has released a "no fire" xinwanda program. According to Xiaobian's understanding, it is ternary battery material that xinwanda "no fire" battery material is selected, which means that the ternary battery is moving towards a new height of safety and is expected to cross the safety threshold with the joint efforts of the industry.

With the increasing popularity of new energy vehicles, car companies and consumers have stronger demands for vehicle safety, "no fire" has become a new direction for battery enterprises to focus on this year. At the beginning of the year, BYD launched a "non fire" blade battery based on its self ignition resistant lithium iron phosphate battery material, through structural and technological innovation. However, looking at the ternary battery, at present, including domestic and even the world, few enterprises have launched "non fire" ternary battery.

From the video content of "no fire" released by xinwanda, it can be seen that through continuous heating of a single cell, the heating is out of control and smoke is emitted, and the temperature of the surrounding cell rises, but the heating is not out of control (there is no thermal diffusion spread). According to industry insiders, "heating trigger is actually a heat triggered experiment which is more severe than acupuncture experiment.". At the beginning of the year, several domestic battery enterprises had a heated argument about acupuncture experiment, believing that acupuncture is the "Mount Everest" of battery safety. However, if the heating can be out of control through heating, without fire and non-proliferation, we can roughly understand how reliable the safety of this kind of battery is.

01

"Different" ternary battery

In the field of power battery, the ternary batteries currently used in China can be divided into ternary 523, ternary 622 and ternary 811 batteries according to the different proportions of nickel, cobalt and manganese in cathode materials. It should be noted that these materials are polycrystalline.

It can be seen from the "no fire" battery plan announced by xinwanda that the ternary battery material is a 5 series single crystal high voltage ternary material nickel 5x cathode material.

It is understood that the use of single crystal materials actually has two advantages: one is more secure; the other is that it can make high voltage, which can improve the energy density.

Because there is no grain boundary in single crystal materials, the stability of ternary materials can be improved and the heat production will be much less.

According to the relevant person in charge of xinwanda, xinwanda adopts single crystal high voltage nickel 5x system material, the heat production is at least 18% lower than other systems, and the thermal stability (thermal runaway temperature) is more than 30% higher than other systems.

In terms of energy density, due to the higher voltage of single crystal materials, the energy density can be increased by increasing the voltage of single crystal materials. It is reported that the energy density of nickel 5x is close to the current 811 material system.

In addition to material safety and thermal safety design, xinwanda also adopts Z-direction extrusion design in mechanical safety design. The advantage of this design is that even if the bottom deformation reaches 15%, the cell is still in a very safe state.

It is worth mentioning that the battery safety design based on material safety, thermal safety and mechanical safety design is only the first level in xinwanda "no fire" battery safety protection system. Xinwanda has also built a "five layer safety design system" through BMS battery management system, battery cell barrier, module level safety design and system level personal safety protection design, so as to realize the battery pack fire-free and ensure personal and property safety.

02

"No fire" will be the safe fresh air direction of battery

Among the various indicators of power battery, safety is the only one that can not be negotiated.

In recent years, with the large-scale popularization of new energy vehicles, vehicle fires occur from time to time. New energy vehicles as a "new thing", so once a fire accident occurs, consumers are more concerned about its safety than fuel vehicles. Although the data shows that the ignition rate of new energy passenger vehicles has been significantly reduced in recent years. For example, the fire rate of new energy vehicles in 2019 is about 0.38 per 10000, while by 2020, the number has been reduced to 0.18 per 10000, and the safety of new energy vehicles has been significantly improved. However, both car companies and consumers want to have "absolutely safe", at least not "spontaneous combustion" vehicles.

From the current situation, although the power battery technology, such as energy density, charging rate, cycle life indicators are rapidly improved in recent years, if there is a potential safety hazard in the battery, then


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