We believe that there are two major technical routes for lithium batteries at present, the cost-effective route represented by square iron lithium and the high-performance route represented by ternary high nickel cylinder.
In the past two years, thanks to the technological progress of CTP and blade battery, square iron lithium has a high cost performance in the passenger car market with a range of 600 km or less. According to the data of xinlune lithium battery, the average price of iron lithium square power cell was 0.77 yuan / wh on March 25, 22, and the average price of three yuan square power cell was 0.84 yuan / wh in the same period Thanks to the blade battery technology, Byd Company Limited(002594) lfp model has an energy density of 140wh / kg and a range of 565km, breaking through the ceiling of lithium iron range.
The advantages and disadvantages of nickel + silicon are more suitable for the market with more than 600km of endurance. The advantage of large cylinder is that it is not easy to heat out of control and the arc surface is more resistant to expansion. The advantage of high nickel ternary is high energy density, while the disadvantage is high cost + poor thermal stability. The change of high cost can rely on the input of ternary integrated nickel smelting to reduce the cost of nickel. The poor thermal stability can be improved with cylindrical packaging. The advantages of silicon-based negative electrode are high energy density + suitable for fast charging, while the disadvantages are high cost + easy expansion. We believe that high cost is the initial stage, which can rely on large-scale cost reduction, easy expansion and can be combined with cylindrical packaging.
This report is a series of new technology reports of high nickel + high voltage + large cylinder – starting with the investment opportunities of new materials from the silicon negative electrode, and extends the investment opportunities of surrounding new materials, such as single wall carbon nanotubes, lithium supplement and PAA binder, which are expected to benefit from the improvement of low base + permeability. In the next few years, the growth rate of market space is considerable, and thanks to the technology premium, the leading profit space is expected to be considerable.
Silicon is the direction of progress of negative electrode materials, and the amount is imminent. At present, the specific capacity of mainstream graphite negative electrode enterprises can reach 355360mah / g, which is close to the theoretical specific capacity of 372mah / g. the negative electrode material needs to be upgraded urgently. The theoretical specific capacity of silicon material reaches 4200mah / g, which is more than 10 times that of graphite. Due to the high expansion rate (300% for silicon and 12% for graphite), the industrialization of silicon negative electrode is blocked. At present, silicon-based negative electrode is mainly used in the fields of high-end 3C digital, electric tools and high-end power batteries, and the permeability of negative electrode is less than 2%. Tesla‘s self-produced battery cylinder made it clear that it uses silicon negative electrode. In addition, car enterprise battery factories such as Panasonic, Samsung, GAC and Weilai also announced the use of silicon negative electrode.
Silicon negative electrode is generally doped into artificial graphite to realize industrialization (at present, the doping proportion is about 5%). According to the selection of silicon materials, it is divided into two technical routes: silicon carbon and silicon oxygen.
Silicon carbon negative electrode: it is made of nano silicon and graphite materials. At present, the commercial capacity is less than 450mah / g and the first effect is high, but the volume expansion coefficient is too large, resulting in poor circulation. It is generally used for consumer batteries for 500600 weeks.
Silicon oxygen negative electrode: mixed with silicon oxide and graphite materials, the current commercial application capacity is mainly 450500mah / g, the first effect is relatively low, but the cycle performance is relatively good, which can be used for consumption and power.
The core of the preparation of silicon carbon negative electrode is ball milling, and the core of the preparation of silicon oxygen negative electrode is the modification of silicon oxide. Just as the silicon negative electrode has the concept of pure product and composite product (the silicon-based negative electrode refers to composite product), the preparation of silicon negative electrode also has two processes. We divide it into the preparation of pure silicon at the front end and the composite with graphite at the back end. We believe that the core is the preparation of pure silicon at the front end. The core of silicon carbon is the preparation of nano silicon, which generally adopts mechanical ball milling method. The core of silicon oxygen is the preparation of silicon oxide, which needs modification treatment. Generally, chemical vapor deposition (CVD) is used for carbon coating.
The unit price and capex of silicon-based negative electrode are significantly higher than those of graphite negative electrode. The price of graphite negative electrode is generally 3 Shenzhen Zhongjin Lingnan Nonfemet Co.Ltd(000060) 000 yuan / ton. According to our calculation, the price of pure silicon negative electrode is generally 3 Shenzhen Quanxinhao Co.Ltd(000007) 00000 yuan / ton, and the price of composite products is generally 8 Csg Holding Co.Ltd(000012) 0000 yuan / ton. The investment of fixed self production per 10000 tons of integrated capacity of artificial graphite anode is generally about 200 million yuan, and the investment of fixed assets per 10000 tons of silicon-based anode, especially the front-end pure silicon, is generally about 1 billion yuan.
At present, Beirui is in the early stage of R & D and mass production of silicon clients in Japan, and Beirui is in the leading position in the industry in China.
Overseas: Japanese and Korean enterprises take the lead in silicon-based negative electrode, mostly at the patent level. For example, Japan Xinyue chemical takes the lead in the number of silicon oxygen negative electrode patents, but its main business is semiconductors, and the quantity level is not leading.
China: beiteri made a technological breakthrough in silicon-based negative electrode materials in 2010 and delivered them in batches in 2013. Its customers are Panasonic and Samsung. Beiteri’s products are continuously updated and iterated, and the specific capacity and first-time efficiency of high-generation products are significantly ahead of their peers. Beiteri has a capacity of 3000 tons of silicon anode (we expect it to be pure product) and a planned capacity of 40000 tons. The peers are still at the level of 100 or 1000 ton pilot line, and there is no large-scale shipment.
Silicon based negative electrode brings large-scale opportunities for derived materials, such as single wall carbon tube, lithium supplement agent and negative electrode binder.
Single wall carbon tube: it can form a developed network inside the material, cover the surface of silicon particles, establish a highly conductive and lasting connection between silicon particles, and significantly improve the cycle life of silicon negative electrode.
Lithium replenishing agent: the formation of SEI film on the surface of silicon negative electrode needs to consume a large amount of lithium source, which makes the first efficiency of silicon-based negative electrode significantly lower than that of graphite. The first irreversible lithium loss of graphite material is 5% ~ 10%, while the irreversible capacity loss of silicon is 15% ~ 35%. Therefore, silicon negative electrode generally needs to be used with lithium replenishing agent.
PAA binder: for silicon-based negative electrode with extremely high volume expansion in charge discharge cycle, reasonable design of binder can greatly improve its cycle life.
Taking the silicon-based negative electrode as the main line, we have derived single-walled carbon nanotubes, lithium supplement and PAA binder. The market space of silicon negative electrode is expected to reach 30 billion + in 25 years, that of other materials is expected to be about 5 billion, and the compound growth rate in 21-25 years is about 100%.
