On March 29, BYD released a new generation of lithium iron phosphate battery “blade battery”. He long, vice president of BYD group and chairman of Fudi Battery Co., Ltd., said: “almost all automobile brands are discussing with BYD on the cooperation scheme based on the” blade battery “technology

More industry insiders said that “blade battery” is BYD’s knife, which will “cut” the market pattern of power battery again.

Why ternary lithium batteries become the mainstream of the market

Before BYD’s blade battery was released, ternary lithium battery was the mainstream choice in the power battery market. Both the installed capacity and the market share were expanding year by year.

According to relevant data, in 2016, the installed capacity of ternary lithium batteries was 6.3gwh, with a market share of 22.6%; by 2019, the installed capacity of ternary lithium batteries reached 38.5gwh, and the market share rose to 61.7%. At the same time, the market share of LiFePO4 has gradually declined year by year. In 2016, the installed capacity of LiFePO4 was 20.3gwh, with a market share of 72.7%; in 2019, the installed capacity of LiFePO4 was 20gwh, with little change in market demand, but the market share fell to 32%.

The key factor causing the market share switching between Li (III) battery and lithium iron phosphate (LiFePO4) is that the government subsidies in the past year have been inclined to high endurance and high energy density vehicles.

Why is ternary lithium battery the mainstream of the market? BYD may set off an upsurge of lithium iron phosphate

According to the subsidy standard for new energy vehicles, in 2017, electric vehicles with a range of more than 100 km can enjoy state subsidies; in 2018, electric vehicles with a range of more than 150 km can enjoy state subsidies; in 2019, the threshold for enjoying state subsidies will be increased to 250 km.

At the same time, the space left for batteries on passenger cars is ultimately limited. The more batteries are loaded and the higher the energy density, it is possible to meet the government subsidy standards. In terms of energy density, the energy density of lithium iron phosphate battery is usually between 90 and 120 WH / kg, while the energy density of ternary lithium battery can reach about 200 WH / kg, which shows that the energy density advantage of ternary lithium battery is obvious. At the same time, the tap density of LiFePO4 battery is only 0.7-1.4g/cm3, which is much lower than that of the ternary material (2.2-2.8g/cm3), which results in a weak specific energy density.

Is the market in the wrong direction?

However, BYD does not recognize that ternary battery has become the mainstream development direction of the market. At the BYD “blade battery” press conference, Wang Chuanfu said: “I believe that the” blade battery “will force the whole new energy vehicle industry to make changes and let the industry enter the fast lane of sound development.”

Although ternary battery has the advantages of high energy density, it is difficult to compare with lithium iron phosphate battery in cost performance and safety.

In terms of cost performance, the core advantage of LiFePO4 battery lies in its low price. As lithium iron phosphate cathode material does not contain rare metals such as cobalt, it has obvious cost advantages compared with ternary materials. According to the market situation at the end of 2019, the price of LiFePO4 cathode material is only 43000 yuan / ton, while that of Sanyuan 523 cathode is 138000 yuan / ton, and the price of Sanyuan 811 cathode is higher than 180000 yuan.

During the period from 2015 to 2015, the price of lithium battery reached the highest of US $80000, which was two times higher than that of lithium battery. The European Union Joint Research Center (JRC) report points out that the demand gap is expected to exceed 64000 tons in 2030.

Under the experimental conditions, after 5000 cycles, the remaining capacity of LiFePO4 battery is 84%, and after 3900 cycles, the remaining capacity is only 66%. In contrast, the cycle life of LiFePO4 battery is much longer than that of lithium ternary battery.

In terms of safety, the decomposition temperature of the cathode material of the ternary lithium battery is about 200 ℃, and the decomposition temperature of the positive material of the lithium iron phosphate battery is about 700 ℃. The short circuit lithium iron phosphate battery monomer will not ignite, but the ternary lithium battery is not.

BYD believes that safety is the core factor of power battery. Wang Chuanfu said: “the biggest feature of blade battery is safety, which will lead the global power battery technology line back to the right path,” and completely erase the word “spontaneous combustion” from the dictionary of new energy vehicles. “

Under the same test conditions, the surface temperature of ternary lithium batteries rapidly exceeded 500 ℃ and extreme thermal runaway combustion occurred. After being punctured, the traditional bulk lithium iron phosphate batteries had no open fire and smoke, and the surface temperature reached 200 ℃ – 400 ℃“ There is no open fire and no smoke after penetrating. The surface temperature of the battery is only about 30 ℃ – 60 ℃.

Ningde times and GuoXuan high tech follow up

In addition to BYD, Ningde era also carries out in-depth development of battery technology. Recently, it was reported from Tesla that Ningde era CTP module free power battery pack technology was used on the domestic model 3.

According to the data, CTP, its full name is cell to pack. The most direct role of CTP technology is to enhance the energy density of battery pack, and then improve the endurance. Due to the low energy density of LiFePO4 battery, which is mainly restricted by the electrochemical characteristics of the three materials, there is no way to achieve a breakthrough in technology in a short time. Therefore, Ningde era improves the energy density by changing the pack form.

It was previously reported that the energy density of CTP lithium iron phosphate battery pack provided by Ningde era for Volkswagen has reached 160wh / kg. Such data can basically meet the requirements of Tesla’s domestic model standard of extended range and the minimum standard of national new energy subsidy policy.

Of course, in addition to lower cost, another characteristic of LiFePO4 battery is good stability, higher safety and longer service life. In addition to the low energy density, the performance of LFP battery is inferior to that of ternary lithium battery at low temperature. What’s more, the overcharge technology Tesla has been emphasizing is still uncertain whether it can be continued on LFP batteries.

In addition, GuoXuan high tech is also developing new technologies. At the end of February this year, GuoXuan high tech said that through the improvement of pack technology and the optimization of battery pack design, GuoXuan high tech lithium iron phosphate battery monomer energy density experiment stage has exceeded 200wh / kg

Editor in charge: WV

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