The safety of ternary battery will be greatly improved

2020-12-14 17:52:05 0

Among the many performance indicators of electric vehicles, only safety has not been measured. In the past decade, the energy density of the battery has been increased by three times, the cost has been reduced by 80%, and the cycle life has been greatly increased by several times Of course, the safety of electric vehicles is not obvious to consumers, but it is not safe for them to accept.

In fact, the safety of the power battery on electric vehicles is also constantly improving and improving. The data shows that in recent years, with the joint efforts of industry colleagues, the ignition rate of new energy passenger vehicles has decreased significantly. For example, the fire rate of new energy vehicles is about 0.38% in 2019, while it has been reduced to 0.18% in 2020, so the safety of new energy vehicles has been significantly improved.

In addition, the safety and stability of power batteries have also been significantly improved. In 2020, the fire accident rate of new energy vehicles equipped with ternary batteries and lithium iron phosphate batteries will be reduced to 0.24% and 0.09% respectively. Five years ago, we didn't have the confidence to say that LiFePO4 battery was safe. Three years ago, we didn't dare to state our position on the safety of Sanyuan ncm333 and ncm523. Now, the safety of lithium iron phosphate and ncm523 has become a consensus in the industry, but the industry is still worried about the safety of high nickel ternary materials such as ncm811. But it can be seen that with the deepening of the research on different material systems, the safety of power battery is also a gradual and steady process.

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The safety of battery is designed and manufactured. In the past, the mechanism of thermal runaway of battery is not very familiar, especially when the material system changes. Now we have a clear understanding of the thermal runaway mechanism of lithium iron phosphate and Sanyuan 333 / 523, so we have a variety of measures to achieve safety, "a few days ago, at the media communication meeting of China electric vehicle 100 people's meeting forum (2021), academician Ouyang Minggao, vice president of China electric vehicle 100 people's Association, said that the mechanism of thermal runaway of new materials such as ncm622 and 811 has changed, and new materials are needed At present, the thermal runaway mechanism of high nickel ternary battery has been basically clarified from the scientific level

The implication is that with the in-depth understanding of the thermal runaway mechanism of high nickel ternary materials, it is expected that the safety of high nickel ternary material batteries (such as ncm622 / 811) will also be greatly improved, providing support for the extensive application in the new energy vehicle market in the future.

It is worth mentioning that the lithium iron phosphate battery is warming up with the breakthrough of technology. According to the data of power battery application branch, in the first three quarters of this year, the installed capacity of LiFePO4 batteries for new energy passenger vehicles in China has exceeded that of last year, which also shows that LiFePO4 is gradually recognized in the new energy vehicle market.

"Lithium iron phosphate could not be used in cars (new energy passenger cars) before. The main reason is that its volume energy density is low, and it can't install enough batteries in the same volume to make it run more than 400 kilometers." Ouyang Minggao said that the blade battery technology (without module technology) has increased the volume energy density of LiFePO4 by about 50%, which can make the driving range of passenger cars equipped with LiFePO4 batteries in the same space reach 600 km, which is a great breakthrough.

At the same time, LiFePO4 material itself is relatively safe, with long cycle life and low cost. Now, with the breakthrough of technology, it can meet the application of long endurance vehicles. Therefore, it is not surprising that the sales of passenger cars equipped with LiFePO4 batteries have increased. The data shows that in the past three months, the loading volume of LiFePO4 batteries has increased by more than 100% year-on-year, and its warming trend is very obvious.

Of course, there is no contradiction between the warming trend of LiFePO4 and the wide application of ternary batteries. "We need balanced development, both ternary and LiFePO4 are required, and ternary safety can be achieved through high technology." Ouyang Minggao said that the industry should continue to increase battery energy density on the basis of safety, and pay attention to safety design and manufacturing in the development of new materials. Ouyang Minggao pointed out that at present, China's batteries have been exported in large quantities due to their good performance price ratio, "but it is impossible for the whole world to use Chinese batteries forever, so the technical competition and competition will continue forever. For example, in the competition of solid-state batteries, the potential for scientific and technological innovation is huge, so we should continue to innovate and make breakthroughs. "

Battery China learned that the forum of China electric vehicle 100 people's meeting (2021) will be held from January 15 to 17, 2021. At that time, experts from new energy vehicles and power battery industry chain will exchange and share hot topics such as battery technology innovation, research on high nickel materials, and power battery safety.