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core viewpoint:
➢ ternary material application has an absolute advantage, and the long-term trend of high nickelization remains unchanged. According to statistics, the cost of the battery system usually accounts for 30%-50% of the vehicle cost, of which the positive electrode accounts for 30%-40%, which is the largest proportion. We believe that the application of ternary materials in new energy vehicles has an absolute advantage, and the long-term trend of ternary materials to achieve high nickelization remains unchanged. There are two main reasons: (1) Although the policy has slowed down in the pursuit of high energy density, its threshold is still reasonably raised, and the energy density is concentrated towards a relatively high value; (2) In terms of demand, consumers are paying more attention to the mileage of new energy vehicles, and the current mileage gap between new energy vehicles and oil vehicles is relatively large, and the contradiction points will promote the process of high nickelization to a certain extent.
➢ The manufacturing cost per unit of electricity of high nickel materials is lower than that of ordinary ternary materials, but the cost of use is still relatively high. Cost splitting results show that although the ton-ton cost of high nickel materials is significantly higher than that of ordinary ternary materials under the combined effect of high lithium source prices and manufacturing costs, due to the difference in the amount of the two positive electrode materials used for the same power, the kwh manufacturing cost of high nickel materials is lower than that of ordinary ternary materials. It is worth noting that since high-nickel materials currently have a significant technological premium, their KWH usage cost is still higher than ordinary ternary materials. As the technology gradually matures, the gross profit margin of high-nickel materials will gradually decline in the future. In addition, we found that if the positive electrode material manufacturer replaces all the purchased precursor with homemade precursors, it is expected to increase the gross profit margin of the positive electrode material by about 6 percentage points.
➢ Changes in raw material prices have relatively little impact on high-nickel materials. The results of sensitivity analysis show that the price change of cobalt source by 10,000 yuan/ton will drive the cost of NCM523 positive electrode material to change by 5%, and at the same time, it will drive the cost of NCM811 positive electrode material to change by 2%. Since the cobalt content in NCM523 is higher than that of NCM811, NCM523 is greatly affected by the cobalt price. The calculation also shows that if the price of cobalt sulfate heptahydrate is higher than 111,500 yuan/ton, the cost of ton of NCM523 will be higher than NCM811; if the price of cobalt sulfate heptahydrate is lower than 40,000 yuan/ton, the cost of kwh manufacturing of NCM811 will be higher than NCM523.
➢ By 
020 , the overall supply and demand of high-nickel materials are tight, and the short-term focus is expected to be NCM622: In terms of supply, according to SMM statistics, the total domestic ternary materials production capacity as of 2018 was 336,700 tons, an increase of 129,300 tons from 2017. According to our statistics, the production capacity of high-nickel materials has exceeded 50,000 tons. The subsequent large-scale expansion plans of mainstream manufacturers are also mainly aimed at high-nickel materials, with NCM811 and NCA being the majority. In terms of demand, we expect the installed demand for high-nickel materials in 2019 and 2020 to be 2.90 tons and 6.13 tons, respectively, respectively, and the proportion of total demand is also increasing year by year. Considering the insufficient actual release of high-nickel production capacity and the installed capacity of power batteries is usually much smaller than the actual shipment, we believe that by 2020, high-nickel materials are generally in a tight supply and demand state. In addition, under the current policy guidance, the development focus of high-nickel materials may be biased towards NCM622, NCM811 and NCA in a short period of time, but given the demand side's pursuit of high-nickel vehicles with high mileage and lightweight, the long-term trend of high-nickelization remains unchanged.
. Analysis on the necessity of high nickelization of ternary positive electrode materials
.1 The positive electrode materials account for a high cost ratio in lithium-ion batteries and have a great impact on performance
New energy vehicles are mainly composed of power systems, chassis, body, interior, automotive electronics and other parts, among which the power systems account for about 50% of the vehicle cost. The power system mainly includes the "three major electric" systems of batteries, motors and electronic control, among which the cost of power batteries is the first to be affected, reaching 76%. According to statistics from Business News, the cost of the battery system usually accounts for 0%-50% of the vehicle cost .
According to statistics from Business Exchange, 0% of the lithium battery cost is the material cost, of which the positive electrode accounts for 30%-40%, the diaphragm accounts for 15%-30%, the electrolyte accounts for 20%-30%, and the negative electrode is 5%-15%, and the positive electrode material accounts for the largest proportion.
km10
km0km material acts as a lithium source in a lithium-ion battery and participates in electrochemical reactions.During the charging process of lithium battery, Li+ takes off from the positive electrode and releases an electron. In the positive electrode, metal ions such as Co3+ are oxidized into the high-valent state; Li+ is embedded in the carbon negative electrode through the electrolyte, and the compensating charge of the electrons is from the external electricity
positive electrode material acts as a lithium source in the lithium-ion battery and participates in the electrochemical reaction. During the charging process of lithium battery, Li+ takes off from the positive electrode and releases an electron. In the positive electrode, metal ions such as Co3+ are oxidized into the high-valent state; Li+ is embedded in the carbon negative electrode through the electrolyte, and at the same time, the compensation charge of the electron is transferred from the external circuit to the negative electrode to maintain charge balance; during the discharge process of lithium battery, contrary to the above process, outside the battery, electrons outside the battery reach the positive electrode, and inside the battery, Li+ migrates to the positive electrode, embedded in the positive electrode, and an electron is obtained from the external circuit, and metal ions such as Co4+ are reduced in the positive electrode. The performance of the cathode material has a significant impact on the cell performance, including but not limited to: (1) The type, usage design and processing of the cathode material affects the energy density of the finished cell product, especially the choice of types, which will determine the upper limit of the energy density of the cell; (2) The type of cathode material, crystal structure stability, particle size, doping atoms, carbon coating process, preparation method, etc. will affect the power density of the cell; (3) The loss of the active substance of the cathode material during recycling, as well as the attenuation of the cathode's ability to accommodate lithium ions during charging and discharging, and the content of impurity components will all affect the cell cycle life. In addition, the amount of positive electrode material used in the battery cell design is much greater than the capacity of the negative electrode material, which will increase the risk of thermal runaway. The material selection and quality of the positive electrode material will have a significant impact on the safety performance of the battery cell. Therefore, the ideal lithium-ion battery positive electrode material should meet the following conditions:
.2 The policy promotes the marketization of new energy vehicles, and the energy density threshold continues to increase
.2.1 The decline in the subsidy amount of new energy vehicles increases year by year
Since 2014, domestic new energy vehicle subsidies have begun to enter the decline stage. The figure below shows the changes in the decline of subsidies (because there are different changes in subsidies for different models, this figure only shows the general trend and does not represent specific numbers). The decline in subsidies has risen rapidly from about 5% from 2014 to about 40% in 2018. The overall decline in subsidies in 2019 has further increased from 2018 to reach a level of about 60%. Looking at the
-point model, the following two figures show more intuitively the changes in subsidy quotas for pure electric passenger cars and passenger cars from 2013 to 2019.
pure electric passenger car subsidies have maintained an overall downward trend since 2013; in 2018, financial subsidies for models with a cruising mileage below 150km were stopped, while subsidies for models with a high-lift mileage turned upward, which is a major feature of the new subsidy policy in 2018; in 019 , financial subsidies for models with a cruising mileage below 1250km were stopped, and the subsidy for models with a high-lift mileage model turned rapidly on the basis of 018 .
The subsidy limit for non-fast charging pure electric passenger buses remains unchanged from 2013 to 2015, and has dropped significantly from 2016, with a significant decline of significantly greater than that of pure electric passenger cars; in 019 , the subsidy limit for models of each length will continue to decline based on 018 .
.2.2 The energy density threshold continues to be raised, and the excess subsidy for high energy density has been slightly alleviated. According to statistics from Table 2, as early as 2009, domestic new energy vehicle related policies began to make requirements for vehicle technical indicators. The initial policies only required the battery capacity and mileage of new energy vehicles. Since 2017, relevant policies have begun to make specific requirements for the energy density and energy consumption standards of new energy vehicle power systems, and the threshold has gradually increased. Among them, energy density is the top priority of the policy's attention to the technical indicators of new energy vehicles.In the new subsidy policy for 019, although the energy density threshold of the power battery system of the three models continues to increase, the attitude towards subsidy for high energy density has changed a certain way: First, the passenger car subsidy standard has added the live quantity indicator to balance the technical level of new energy vehicles from the policy end; Second, although the energy density threshold of passenger cars continues to increase, the highest standard has not been further improved, and the policy will no longer set excess subsidies of more than 2 times the energy density of html to avoid excessive pursuit of high subsidy amounts and neglect other performance indicators; Third, the classification standard for subsidy adjustment coefficient of non-fast charging pure electric buses has changed from the system energy density to the unit mass-load energy consumption, in the passenger The vehicle level has weakened the impact of energy density indicators; fourthly, the cancellation of the threshold requirement of the total mass of the new energy bus battery system to the vehicle curb mass (m/m) is not higher than 0% , which to a certain extent curbs the bad direction of blindly pursuing high-energy density power batteries.
.2.3 Solving "mileage anxiety" is a key link in the demand side of new energy vehicles
"mileage anxiety" for new energy vehicles has become one of the most concerned issues for ordinary consumers. The main reasons include the large gap between the existing new energy vehicles and traditional oil vehicles, insufficient infrastructure construction of charging piles, and severe attenuation of electric vehicles under extreme environmental conditions. Among them, short mileage is still the main reason.
In the table below, we have selected representative oil vehicles and pure electric vehicles in each price range to compare the mileage. As can be seen in the table, the mileage of oil vehicles has basically not changed much at various prices, and consumers usually do not pay much attention to the mileage of oil vehicles, and the mileage of tram has increased significantly with the increase in price, ranging from 00km to 00km . Consumers usually pay more attention to the mileage of tram. Comparison of
shows that there is indeed a big gap in the mileage of traditional energy vehicles and new energy vehicles. The mileage gap between models under 200,000 is basically above 60%, or even 70%. The gap between models over 300,000 is narrowed, but even considering the mileage of Tesla Model 3 nearly 600,000, the minimum average gap has reached nearly 40%. Since consumers generally prefer low-priced models, the mileage gap of 0% or above has become the culprit of " mileage anxiety " . From the demand side of new energy vehicles, increasing the energy density of power batteries has become a key link.
.3 Triple-alloy positive electrode material has an absolute advantage, and the long-term trend of high nickelization remains unchanged
.3.1 Triple-alloy positive electrode material is the most preferred power battery for new energy vehicles
0 The figure below compares the performance of the five commonly used battery materials in six dimensions: safety, specific energy, specific power (the battery's large-scale charging and discharging ability), high and low temperature performance, life and cost. It can be seen in the figure that lithium iron phosphate materials, which have been widely used on a large scale and have obvious advantages in terms of safety and service life; although the two ternary materials of nickel-cobalt manganese oxide (NCM) and nickel-cobalt lithium aluminate (NCA) are slightly inferior in terms of safety performance, life and cost, they have absolute advantages in terms of specific energy; lithium cobalt oxide, which is not listed in the figure, is one of the most energy-density positive electrode materials, is not suitable for large-scale application in general new energy vehicles due to its high cost. Given that the current policies and application orientations are directed towards high-energy-density power batteries, ternary materials have become the best option and have gradually gained an advantage in applications.
.3.2 ternary materials have already occupied a significant advantage in applications
According to real lithium research statistics, the total installed capacity of power batteries in 2017 was about 33.55GWh, of which ternary batteries accounted for about 45%; in the monthly installed capacity data in 2018, the proportion of ternary batteries exceeded the annual value of 2017. After the new subsidy policy was officially implemented in mid-June, the proportion of ternary batteries in a single month once reached more than 70%; 018 , the total installed capacity of power batteries was about 6.46GWh, of which ternary batteries accounted for about 0% , which increased by about 017 . 5 percentage points.
019 total installed power battery in February was .98GWh, of which the proportion of installed ternary batteries further increased to 9.68% . The proportion of the data has increased significantly both year-on-year and month-on-month, almost the same as the highest value of 018 .
passenger cars are the models with the strongest demand for mileage and energy density and the most ternary materials are used; at the same time, pure electric passenger cars account for a large proportion of sales, and are models that face ordinary consumers and the vast market, with the greatest development potential. The choice of power batteries for pure electric passenger cars will directly determine the direction of future power battery technology routes. As shown in the figure below, the monthly data on the proportion of ternary installed pure electric passenger cars in 018 exceeded the annual level of 017 , and the annual level of 018 reached nearly 0% .
019 pure electric passenger car battery installed .22GWh, of which the proportion of installed ternary batteries has further increased to more than 5% . Three-yuan batteries have occupied a significant advantage in applications.
.3.3 The energy density gap is mainly in the positive electrode material. The long-term trend of high nickelization remains unchanged. The active energy storage material of lithium-ion batteries is a positive and negative electrode material. The energy density of the battery system mainly depends on the energy density and matching of the positive and negative electrode material itself. For the positive electrode, increasing the discharge voltage and discharge capacity is an effective method to increase the energy density. For the negative electrode material, it is to increase the capacity and reduce the average deliquification voltage. The following table lists the theoretical specific capacity of each subdivided positive electrode material and negative electrode material.
Currently, the monomer specific capacity of commonly used negative electrode materials is 250mAh/g or above, while the monomer specific capacity of commonly used positive electrode materials is below 200mAh/g except NCM811 and NCA. Looking back at the previous drafting of the Ministry of Industry and Information Technology's "Made in China 025" that the energy density of power batteries reaches 50Wh/kg in 020 , the current energy density gap is obviously in the positive electrode material link. Although the new subsidy policy for 019 has alleviated the application speed requirements of high-energy density power batteries, the policy is mainly based on application safety considerations. In fact, from the demand side, consumers' attitudes towards high-energy density and high-lift mileage models have not changed, and the long-term trend of high-nickel NCM and NCA remains unchanged.
. Structural characteristics and technical points of high nickel ternary materials
.1 Structural characteristics and the impact of increased nickel content on material properties
.1.1 Structural characteristics and mechanism of action of each element
ternary materials Li(Ni,Co,Mn)O2 crystals belong to the hexagonal crystal system and are a type of layered structural compound, as shown in the figure below. The ternary materials contain three transition metal elements: Ni, Co, and Mn, which exist in the valence states of +3, +2, and +4 respectively. The pairs participating in the electrochemical reaction are Ni2+/Ni3+, Ni3+/Ni4+ and Co3+/Co4+ respectively.
Ni acts as one of the active substances in ternary materials and participates in electrochemical reactions. Its existence can improve material activity and energy density. However, since the Ni2+ present in the lattice is similar to Li+, cationic mixed discharge is easily caused, and as the Ni content increases, the mixed discharge becomes serious, which will directly affect the electrochemical performance of the material, reduce the discharge specific capacity, and hinder the diffusion of Li+. The figure below shows the I(003)/I(104) ratio of different proportions of NCM. The lower this value, the more serious the cationic mixed discharge is.
Co also exists as an active substance in ternary materials and participates in electrochemical reactions. The higher the content of Co, the more stable the layered structure formed, and it can reduce the mixed discharge of cations, facilitate deep discharge of the material, thereby increasing the discharge capacity of the material. However, the increase in the content of Co will significantly increase the raw material cost of the ternary material.
Mn does not change during the charging and discharging process of the battery, and plays a role in stabilizing the structure. The MnO6 octahedral formed can play a role in supporting the structure in the electrochemical process; in addition, the addition of Mn elements will reduce the cost of the ternary material to a certain extent.
ternary material basically comprehensively reflects the advantages of the above materials, and has different properties and characteristics depending on the content of each component.
.1.2 The impact of high nickel content on the performance of ternary materials
Comprehensively described in the previous section, the advantages of different proportions of NCM materials are different. Ni shows high capacity and low safety; Co shows high cost and high stability; Mn shows high safety and low cost. At present, the focus on increasing the energy density of power batteries is mainly to increase the specific capacity of the positive electrode material. The most mainstream view is to increase the nickel content of the ternary material.
nickel acts as an active ingredient in ternary positive electrode materials. The higher the nickel content, the more electrons can participate in electrochemical reactions, and the higher the discharge specific capacity of the material. However, the increase in nickel content will also have a series of impacts on the performance of the material:
) High nickel affects the circulation performance of the positive electrode materials: First, as mentioned above, Ni2+ in ternary materials are prone to mixing and discharging effects with Li+. The higher the nickel content in high nickel materials, the higher the Ni2+ content, which leads to the serious mixing and discharging, forming a non-metered specific material, and affecting the circulation and rate performance of the material; secondly, high nickel will cause the material to undergo multiple phase changes during the circulation process, increasing internal resistance, and affecting the material's circulation performance.
) High nickel increases the residual alkali content on the surface of the material: For high nickel materials (especially high nickel materials with nickel content greater than 60%, it is easy to react with CO2 and H2O in the air, and Li2CO3 and LiOH are produced on the surface of the material. The former will cause severe bloating of the material during storage at high temperature, especially in a charged state, and the latter will react with LiPF6 in the electrolyte to produce HF. The difficulty in controlling the residual alkali content of high nickel materials will have a great impact on the processing and electrochemical performance of the battery. The following figure lists the residual alkali amount on the surface of ternary materials in each proportion. It can be seen that the total residual alkali amount on the surface of NCM811 is nearly 5.5 times higher than that on the NCM622. Controlling the residual alkali amount will be one of the major issues in the preparation process of high-nickel materials.
) High nickel affects the thermal stability of the material: For materials with high nickel content, since the Li removed at the same potential is higher than those of low nickel content materials, the Ni4+ content must be higher. Ni4+ has a strong tendency to reduce, and Ni4+ is prone to reactions from Ni4+→Ni3+. In order to maintain charge balance, oxygen will be released from the material, which will make the stability worse.
) High nickel materials have higher requirements for electrolytes: the reaction and charge transfer at the interface between the electrolyte and the positive electrode materials will affect the performance and stability of lithium-ion batteries. Corrosion of active materials and decomposition of electrolytes seriously affect the transmission of charge at the electrode/electrolyte interface. In addition, due to the high surface LiOH and Li2CO3 content of ternary materials with high nickel content, they are prone to react with the electrolyte during storage of batteries, especially under high temperature conditions, which causes the dissolution of Co and Ni ions to reduce the cycle life and storage life under HF corrosion. Therefore, high-nickel materials have higher requirements on electrolytes than low-nickel materials.
.2 Preparation technology of ternary materials and process specialization of high nickel materials
Preparation methods of ternary materials mainly include high-temperature solid phase method, sol-gel method, chemical co-precipitation method, hydrothermal synthesis method, spray drying method and melt salt method. Since high-nickel ternary materials have high requirements for the uniform distribution of principal components, inhibiting phase separation of precipitates, controlling the residual lithium amount of materials, and managing metal foreign matters, they usually use chemical co-precipitation method to make the precursor, and then prepare the positive electrode material through high-temperature solid phase reaction. In the preparation of finished products of
ternary material, the high-temperature solid phase method usually uses nickel, cobalt, manganese and lithium hydroxide or carbonate or oxide as raw materials, and mixes according to the amount of the corresponding substance, and calcines at 700~1000°C to obtain the product. The main process flow of the high-temperature solid phase method includes nine major processes: lithiation mixing, trashing, crushing and grading, batch mixing, iron removal, screening, and packaging and storage. The control of each link and the performance of the equipment will have a direct or indirect impact on the final product. The most core production link of the high-temperature solid phase method is the mixing abrasives in the lithiated mixing, the high-temperature sintering in the kiln and the pulverization and decomposition after sintering. The most core equipment includes mixing machines, sintering furnaces, crushers, iron removal machines, etc.
.2.1 Lithium source: Preparation process and usage cost comparison
Common lithium sources include lithium carbonate (Li2CO3), lithium hydroxide (LiOH·H2O), lithium nitrate (LiNO3), etc. Lithium nitrate will produce harmful gases in use, so the first two lithium sources are usually used in the preparation of ternary materials, especially lithium carbonate. Although lithium hydroxide monohydrate is better than lithium carbonate in terms of reaction activity and reaction temperature, since the lithium content of lithium hydroxide monohydrate fluctuates more than lithium carbonate, and the corrosiveness of lithium hydroxide is stronger than lithium carbonate, if there are no special circumstances, ternary material manufacturers tend to use lithium carbonate with stable content and weak corrosiveness.
The key quality points of lithium carbonate used to prepare ternary materials are lithium content, impurity content, and particle size distribution. As can be seen from the following flow chart, in the preparation of lithium carbonate by spodumite, the impurity content is mainly controlled in the neutralization process, alkalization process and ion exchange; in the preparation of lithium carbonate by brine, the impurity content is mainly controlled in the addition of alkali liquid, carbon dioxide and lithium precipitation process. In addition, the particle size distribution of lithium carbonate products produced by different manufacturers is usually different.
The key quality of lithium hydroxide used for preparing ternary materials is the same as lithium carbonate. It also removes most impurities in the neutralization filtration, alkalization and ion exchange processes, and the CO32-impermeability content is controlled by using a closed system.
In the following table, we calculate the cost of the two lithium sources in the preparation of ternary materials (taking the current mainstream NCM523 as an example). The average price of lithium sources is the average price in the first two months of 2019. It can be seen that since the lithium content of lithium hydroxide monohydrate is lower than that of lithium carbonate, its unit consumption is slightly higher than that of lithium carbonate, and as of now, the average price of lithium hydroxide monohydrate is still significantly higher than that of battery-grade lithium carbonate, so the former is about 158% than the latter's wh . Therefore, if there is no special demand for lithium hydroxide monohydrate, as mentioned above, ordinary low-nickel ternary materials use lithium carbonate as the lithium source.
.2.1.2 Lithification ratio: In industrial production, consistent ternary material calcination reaction formula is as follows:
M(OH)2+0.5Li2CO3=LiMO2+0.5CO2↑+H2O↑(1) M(OH)2+LiOH·H2O+0.25O2=LiMO2+2.5H2O↑(2)
Where the lithium sources of formula (1) and formula (2) are lithium carbonate and lithium hydroxide monohydrate respectively, the lithiation ratio is the ratio of Li/M in the reaction formula, which is in practice In international applications, the actual value of the lithiation ratio will be affected by the impurities and moisture content in the precursor and lithium source. Generally speaking, the lithium ratio range of ternary materials is between .02 and 1.15. The lithiation ratio in the calcination reaction will have a significant impact on the specific capacity, circulation performance, surface free lithium content and material pH value. The most suitable lithiation ratio value of
is easy to find in the laboratory, but during the production process, we need to control the product of each batch to reach the same capacity value, which requires the following: (1) Strictly control the product quality and batch stability of the ternary material precursor and lithium source supplier; (2) Accurately detect the total metal content of the ternary material precursor and the lithium content of the lithium source; (3) Use mixing equipment with good mixing effect to ensure that the lithiation value of each point of the mixed material is basically the same.
.2.1.3 Mixing process and equipment: High-speed mixing machine is the most preferred
In the production of ternary materials, lithiated mixing is to add the lithium salt, precursor and additive of the stoichiometric ratio to the mixing equipment for uniform mixing. The compounding process determines the stability and uniformity of the lithium ratio of the ternary material. The stability depends on the accuracy of the raw material weighing, and the uniformity depends on the mixing effect of the mixing machine. It will affect the uniformity of lithium and additives during the sintering process, and directly affect the crystallization degree and residual alkali of the ternary material, which is ultimately reflected in electrical properties. Mixing is generally divided into wet mixing and dry mixing. Ternary materials are usually mixed by dry mixing, which is simple and easy to use and low energy consumption compared to wet mixing.
Currently commonly used ternary material mixing equipment include oblique mixing machines (usually adding abrasives), high-speed mixing machines, V-type mixing machines, coulter flying knife mixing machines, etc. The advantages and disadvantages of several mixing machines are as follows.
Currently, in the production of ternary materials in the industry, the inclined mixer and high-speed mixer are basically used, and high-speed mixer is better than inclined mixer in many aspects. The following table compares the high-speed mixer with a volume of 500L and the inclined mixer with a volume of 1500L as an example.
From the above table, it can be seen that the high-speed mixer is significantly better than the ball mill mixer in four aspects: loading rate, mixing time, loading and unloading time and grinding medium; in addition, in terms of mixing effect, the high-speed mixer is also significantly better than the ball mill mixer. As shown in the following table, the lithiumization ratio of different sampling points in the high-speed mixer is obviously more uniform.
.2.2 Packing bowl: When sintering ternary materials, you should choose a large notched silo
After mixing the ternary materials, you need to put the mixed material into the silo, and level and cut the mixed material into small pieces. Then, the silo silo and the corresponding pads to the kiln inlet roller rod. At the outlet of the kiln, the calcined material is poured into the barrel, clean the cassette and check whether there are any damage or cracks in the cassette to determine whether it can be used again. In order to improve production efficiency and save labor, the equipment manufacturer uses automated equipment to complete the above process, namely the "Three-way Material Cassette Automated Loading and Unloading System", which mainly consists of 8 parts: a feeder, a shaker, a cushion cutter, a crusher, a material pouring device, a cassette cleaning device, a cassette crack detection device, and a conveying system.
According to data, the specifications (length, width and height) of commonly used ternary materials are mainly: 320mm×320mm×60mm, 320mm×320mm×65mm, 320mm×320mm×70mm, 320mm×320mm×75mm, 320mm×320mm×85mm, 320mm×320mm×100mm, etc.; the shape of the silhouette is flat bottom with notches, flat mouth with feet, and flat mouth without feet. A special case for lithium battery materials supplier summarizes the appearance and performance of the case used for different sintering components. As shown in Table 11 below, a large notch should be selected for the notch of the case for the firing lithium cobalt oxide and ternary materials, and the material density is relatively high and has good corrosion resistance.
The choice of calcined silo for ternary material generally needs to meet the following conditions: 1. Resistant to alkali corrosion and is not easy to react with raw materials; 2. Good thermal stability; 3. High-temperature load softening point is higher than the calcining temperature; 4. Good thermal conductivity, good hot and cold degeneration; 5. Good breathability.
currently used for calcining the positive electrode material of ternary lithium-ion batteries is generally corundum, mullite, cordierite, etc. Cordierite silhouettes have excellent corrosion resistance and thermal shock stability. They can be used for general purposes in an oxidation atmosphere of 1350°C for more than 100 times. However, when
is used to silencing the positive electrode material of lithium cobalt oxide battery material, even if the firing temperature is reduced to 1000°C, the service life is only 5 to 6 times; when corundum and mullite silencing the battery material, its service life is also greatly reduced.
During the high-temperature calcination process, compared with lithium cobalt oxide, the ternary material causes more serious corrosion on the silo material. According to data, when calcining trimetal materials, cracking and internal corrosion and slag removal are the main reasons for the damage of the sachet. Generally speaking, the higher the aluminum content, the stronger the corrosion resistance of ternary materials, the less likely it is to cause peeling, slag dropping and other phenomena. Corundum-mullite and alumina have good corrosion resistance, but they have the characteristics of poor cold and heat degeneration, which is prone to cracking and damage and is expensive. In the actual production process, mullite and mullite-cordier are mostly made of. A single box can be used 10 to 15 times, but generally slight peeling and slag loss begins to occur about 4 times and gradually intensify. Therefore, some manufacturers have developed zirconium-mullite box based on this, which has better corrosion resistance and longer service life.
.2.3 Kiln calcination: One of the most critical processes
calcination process is one of the most critical processes for processing ternary material precursors into ternary materials, and it has a great impact on the physical and electrochemical properties of ternary materials.
.2.3.1 Calcination parameter control: Temperature, time, atmosphere
The most important elements in the calcination process of ternary materials are the three major elements: calcination temperature, calcination time, and calcination atmosphere. Among them, the calcination temperature and calcination time are not independent of each other. When the calcination temperature is slightly higher, the calcination time can be appropriately shortened; if the calcination time is too long, the calcination temperature can be appropriately adjusted.
) Calcination temperature control: The calcination temperature directly affects the capacity, efficiency and circulation performance of the material, and has a significant impact on the lithium carbonate on the surface of the material and the pH value of the material. Increased temperature has little effect on the loose density of the material, but has a greater impact on the tap density of the product. However, excessive temperature will cause secondary crystallization of the compound and affect the deintercalation of lithium ions in the material. Therefore, a moderate calcination temperature needs to be selected. In addition, the calcination temperature of the ternary materials of different components is also different. Generally, the higher the nickel content of the ternary materials, the lower the calcination temperature, as shown in the figure below.
) Calcination time control: Within a certain range, the calcination time has little impact on the material capacity, specific surface area, tap density, and pH, but it has a great impact on the material surface lithium residue and the product single crystal particle size.
) Calcination atmosphere control: From the calcination reaction equation above, it can be seen that the calcination process of ternary materials is an oxidation reaction, which requires oxygen consumption. During the calcination of ternary materials, in order to increase the diffusion rate of the gas, it is necessary to ensure that there is enough oxygen partial pressure. Although the oxygen partial pressure can be increased by adopting a pure oxygen atmosphere or reducing the calcination amount, considering the production cost, while increasing the production capacity, manufacturers generally choose to increase the intake and exhaust volume to increase the oxygen partial pressure.
.2.3.2 Calcining equipment: Roller kilns are the most widely used
calcining equipment mainly refers to kilns. Pushing plate kilns and roller kilns are continuous tunnel kilns used by ternary material manufacturers, among which roller kilns are the most widely used.
.2.4 Crushing: jaw crushing → roller crushing → airflow crushing
One of the important quality indicators of ternary materials is particle size and particle size distribution, which will affect the specific surface area, tap density, compaction density, processing performance and electrochemical properties of ternary materials. After the mixture of ternary material precursor and lithium source is calcined at high temperature in the casing, the calcination rate is more than 24%, so the material plate is severe. It is necessary to first use a crushing equipment to crush a large piece of material several centimeters into small pieces of material a few millimeters, and then use a grinding equipment to grind the small piece of material into the final product. The common ternary material crushing process flow is: jaw crushing → roller crushing → airflow crushing (or mechanical crushing).
According to the size of the produced particles, crushing can be divided into crushing and grinding. Crushing refers to the processing process of breaking large pieces of materials into small pieces of materials, and grinding refers to the processing process of breaking small pieces of materials into fine powder materials. The following table lists the crushing particle size and production capacity comparison of commonly used equipment in the ternary material crushing process. It should be noted that the hardness of the ternary material is relatively large and pH is greater than 0, which is an alkaline substance. The crushing equipment needs to be resistant to alkali corrosion and wear.
In the crushing of ternary materials, an air-flow crusher can be used or a mechanical crusher can be used. The two types of crushing equipment have their own advantages and disadvantages. Generally speaking, after the airflow crusher, an airflow grading device will be directly added to directly classify the crushed products.
.2.5 Iron removal: an important link throughout the entire process
ternary materials will bring a series of metal impurities in the process. The existence of metal impurities, especially elemental iron, will cause a short circuit in the battery, and in severe cases, it will cause the battery to fail. Therefore, magnetic separation of iron removal is an indispensable link in the process of ternary materials, and it runs through the entire process of ternary materials. The following table 16 lists the sources of metal impurities in the ternary material process.
Commonly used iron removal equipment in the preparation of ternary materials include pipeline iron removal machines and electromagnetic magnetic separators. Among them, the pipeline iron deductor is installed on the material conveying pipeline and is used in each conveying link; the electromagnetic magnetic separator is mainly used in iron deducting before packaging of finished ternary materials.
.2.6 Screening/Packaging
To avoid foreign matter or coarse particles in the material, the ternary material needs to be screened before packaging. According to the data, the DMAX of the ternary material should be at least less than 50μm. According to the mesh comparison table of the standard screen, ternary material needs to choose 300 mesh or 400 mesh screens. It should be noted that since iron impurities or other metal impurities should be avoided during the process of ternary materials, the material of the screen should be non-metallic and has good alkali corrosion resistance.
Common screening machines include fixed grid screens, cylinder sunscreens, vibrating screens, etc. The commonly used screening machines for ternary materials are vibrating screens, and ultrasonic controllers and vibrating screens are often used in combination, which are called ultrasonic vibrating screens, which make the screening effect and performance better.
ternary materials can be packaged after screening. This is also the last step in the ternary materials processing process. They are usually carried out by vacuum packaging or vacuuming and then filled with inert gas.
.2.7 Preparation of high-nickel ternary materials: The process conditions are more stringent, and the equipment requirements are stricter
Compared with ordinary ternary materials, high-nickel ternary materials have more stringent requirements in terms of raw materials, preparation methods and process flow. Correspondingly, the requirements for core equipment in the process flow will also be higher. According to the summary of public information, the difference between high-nickel ternary materials and ordinary ternary materials during the preparation process is mainly as follows:
) Lithium source: Lithium sources of ordinary ternary materials usually use lithium carbonate, while lithium sources of high-nickel ternary materials must use lithium hydroxide. The main reasons for the above-mentioned application differences are as follows: First, for high-nickel ternary materials, the temperature required to be higher than 800°C during sintering. Lithium carbonate is used as raw material. Too low sintering temperature will cause incomplete decomposition, resulting in too strong alkalinity, increased sensitivity to humidity, and affect battery performance; Secondly, high-nickel ternary materials have requirements for oxygen concentration when sintering. When lithium carbonate is used as lithium source, carbon dioxide is used to dilute the oxygen concentration; when lithium hydroxide is used as lithium source, only water vapor is used. Correspondingly, humidity control requirements are also higher in the process.
) Precursor reaction conditions: Due to the different precipitation of nickel, cobalt and manganese, the optimal reaction of precursors of different components of ternary materials is different. According to data, as the nickel content of the precursor increases, the required ammonia water concentration and reaction pH value are increased accordingly.
) Mixing equipment: Due to the unstable surface structure of ordinary ternary materials, in the case of high-nickel materials, strong alkaline lithium hydroxide and lithium carbonate will be generated on the surface of the material under high environmental humidity. The slurry is prone to jelly form, and the higher the nickel content in the material, the more serious this situation is; another reason for this phenomenon is that the uneven mixing of ternary materials during the production process, which in turn affects the uniformity of lithium and additives during the sintering process, directly affects the crystallization degree and residual alkali amount of the ternary materials, and is ultimately reflected in electrical properties. Since high-speed mixers have better mixing effects than ball mill mixers, high-nickel material mixing equipment adopts high-speed mixers, while ordinary ternary materials, especially old production lines, can also use ball mill mixers; in addition, high-nickel material mixing equipment should also have better alkali corrosion resistance and humidity control ability.
) Cassette type and charge amount: According to the above, the ternary material has higher requirements for the breathability of the cassette during the sintering process, while the high nickel material has more requirements for oxygen concentration. Therefore, the air permeability port of the cassette for high nickel materials is relatively large; in addition, the number of stacked layers and charge amount of the cassette also have an impact on the inlet of oxygen and the discharge of exhaust gas, and the charge amount of the cassette is relatively large. Therefore, the cassette of the cassette of the high nickel material has less than that of ordinary ternary materials.
) Number of sintering times: Ordinary ternary materials usually use primary sintering, but high-nickel materials are more likely to have high surface residual alkali. Domestic manufacturers currently use the method of washing high-nickel materials and then sintering them at a lower temperature to reduce the surface residual alkali.It should be noted that although the water washing + secondary sintering method can clean the residual alkali on the surface of the material relatively cleanly, the ratio and circulation performance of the ternary material after treatment will be affected. Therefore, the control of residual alkali should still run through the entire preparation process of the ternary material. The ammonia content and partial pressure of the protective atmosphere should be controlled in the precursor stage, and even an appropriate amount of additives can be added to reduce the carbon and sulfur content to achieve one-time sintering.
) Calcination temperature: As mentioned above, the higher the nickel content of the ternary material, the lower the calcination temperature. The calcination temperature of ordinary ternary material with a nickel content of 0% and below is usually above 00 °C, while high nickel materials are usually below 00 °C. This is mainly because too high temperature can easily cause lithium-nickel mixed discharge, making it difficult to sinter out high-nickel layered materials with metering ratio, affecting material performance
) Calcining atmosphere: In terms of air intake, ordinary ternary materials can be sintered in an air atmosphere, high-nickel ternary materials have high requirements for oxygen atmosphere, and sintering needs to be carried out in a pure oxygen atmosphere; in terms of exhaust gas, ordinary ternary materials use lithium carbonate as the lithium source, the waste gas is carbon dioxide and water vapor, high-nickel ternary materials use lithium hydroxide monohydrate as the lithium source, and the waste gas is mainly water vapor.
) Calcining equipment: Since high nickel materials must be synthesized at high temperature in a pure oxygen atmosphere, the kiln material must be resistant to oxygen corrosion; in addition, high nickel ternary materials use lithium hydroxide as the lithium source, which is volatile and has strong alkaline properties, and the alkali corrosion resistance of the kiln material must be very good. At present, the production of high-nickel ternary materials mainly uses sealed roller kilns. There are relatively few companies in China that can produce such equipment, and it is temporarily unable to fully meet the preparation requirements of high-nickel ternary materials.
. Cost Split and Sensitivity Analysis of Ordinary Terminal Materials and High Nickel Terminal Materials
Comparing the manufacturing costs and usage costs of ordinary ternary materials (represented by NCM523) and high nickel ternal Materials (represented by NCM811), we have made a detailed cost split in this chapter on the above two materials from precursor preparation to the preparation of the finished product of the positive electrode material (split data mainly comes from the project environmental impact assessment reports of many precursor and positive electrode material manufacturers).
.1 NCM523 and NCM811 Cost Split: High Nickel Material kwh Lower Manufacturing Cost
.1.1 NCM523 Cost Split
Currently, the preparation of positive electrode materials mostly uses co-precipitation method (precursor) + high-temperature solid-phase method (positive electrode material). The following formula (1) and formula (2) are the chemical reaction equations of NCM523 precursor and positive electrode materials:
NiSO4·6H2O+CoSO4·7H2O+MnSO4·H2O+NaOH → NixCoyMn(1-x-y)(OH)2+NH3+NaSO4+H2O(1) Ni0.5Co0.2Mn0.3(OH)2+0.5Li2CO3+0.25O2=LiNi0.5Co0.2Mn0.3O2+0.5CO2↑+H2O↑(2)
According to the above chemical equation, we calculated the theoretical feeding amount of raw materials required to produce 1 ton of precursor/positive material, and compared it with the actual feeding amount of the manufacturer, as shown in the following table. During the preparation of the precursor, cobalt sulfate is actually put out more excess amounts; and during the preparation of the positive electrode material, the actual feeding of the precursor and the lithium source are both excessive, and the proportion of excess of the lithium source is relatively high.
Combining the data and information given in the environmental impact assessment reports of each manufacturer, we have made detailed breakdowns on the costs of NCM523 precursor and cathode materials in the following table. The other main assumptions are as follows:
(1) As a complexing agent, assuming that there is no recycling of liquid ammonia, each batch is newly purchased; (2) Assuming that the labor cost is 73,000 yuan per capita per capita; (3) All the price data in the table are data from March 18, 2019.
is split from the above cost, and we have reached the following conclusion:
has completely made NCM523 precursors and the gross profit margin of the positive electrode material manufacturer is expected to be nearly 2 percentage points higher than that of the manufacturers who purchase precursors and .
.1.2 NCM811 Cost Split
NCM811 Positive electrode material preparation is also made by co-precipitation method (precursor) + high-temperature solid-phase method (positive material). The equation prepared by the precursor is the same as that of the NCM523 precursor, and is only for the feed ratio change. The following formula (3) is the chemical reaction of the NCM811 Positive electrode material Equation:
Ni0.8Co0.1Mn0.1(OH)2+LiOH·H2O+0.25O2=LiNi0.8Co0.1Mn0.1O2+2.5H2O↑(3) Similarly, according to the above chemical equation, we produce 1 ton of NCM811 The theoretical feeding amount of raw materials required for the precursor/positive electrode material is calculated and compared with the actual feeding amount of the manufacturer, as shown in the table below. During the preparation of the precursor and positive electrode material of NCM811, the actual feeding value and the theoretical feeding value are relatively close, and the excessive feeding phenomenon is not obvious.
Combining the data and data given in the environmental impact assessment reports of each manufacturer, we have also made a detailed split of the costs of NCM811 precursor and positive electrode materials in the following table, with the main assumption conditions being the same as NCM523. The cost structure of the preparation of
NCM811 precursor and positive electrode material is basically the same as that of NCM523. However, since sintering of NCM811 needs to be carried out under an oxygen atmosphere and secondary sintering is required, the electricity bill and oxygen account for a relatively high proportion of the manufacturing cost of NCM811 positive electrode material.
Similarly, we obtained the cost data of homemade NCM811 precursor and positive electrode material based on the above cost splitting results, and obtained the price data of NCM811 positive electrode material and purchased precursor by querying wind and CBC nonferrous network data. The gross profit margins of the purchased precursor and self-made precursor during the preparation of the positive electrode material were calculated and compared. The results are shown in the table below.
According to the above calculation results, the gross profit margin of the positive electrode material manufacturer that completely made NCM811 precursor is expected to be nearly 2 percentage points higher than that of the manufacturers who purchased precursors.
.1.3 Comparison of the cost splitting results of ordinary and high-nickel ternary materials
We compared the cost splitting results of the above ordinary and high-nickel ternary materials as follows. Figure 35 below compares the total cost of ordinary and high-nickel ternary materials. It can be found that the precursor costs of the two ternary materials are almost the same, while the lithium source used in NCM811 is the more expensive lithium hydroxide unit. Therefore, the high-quality raw material cost of high-nickel ternary materials mainly comes from high-cost lithium sources. However, in terms of proportion, since the manufacturing difficulty of NCM811 is more stringent and the requirements are more stringent, the raw material cost of high-nickel materials is relatively small, and the manufacturing cost accounts for a relatively large proportion.
In the figure below, we enlarge the manufacturing costs of the two ternary materials. Although the sintering temperature of high nickel materials is significantly lower than that of ordinary ternary materials, since high nickel materials usually require secondary sintering, the electricity consumption cost of NCM811 positive electrode materials is significantly higher than that of NCM523 positive electrode materials; in addition, the sintering process of high nickel ternary materials must be completed under an oxygen atmosphere, so the manufacturing cost of NCM811 positive electrode materials is one more oxygen cost than that of NCM523 positive electrode materials.
In the following table, we compare the unit manufacturing costs and unit usage costs of ordinary and high-nickel ternary materials based on the cost splitting results. The results show that the manufacturing cost and usage cost of NCM811 are significantly higher than that of NCM523, which is the result of the joint effect of high-priced lithium sources and high manufacturing costs of high nickel materials; in terms of kwh cost, since the use of high-nickel materials required to achieve the same amount of electricity is significantly lower than that of ordinary trimetal materials (according to research, the amounts of NCM523 and NCM811 are required to produce 1Gwh batteries, respectively), so the manufacturing cost of kwh of can be slightly lower than that of NCM523, but from the perspective of downstream manufacturers to purchase, based on the current selling price, the usage cost of NCM811 is still higher than that of NCM523. NCM523. It can be said that although the manufacturing cost of NCM811 is theoretically lower, the manufacturing process of NCM811 is relatively complex, and the number of positive electrode material manufacturers that can produce qualified NCM811 products is limited, so positive electrode material manufacturers can obtain a higher technical premium.In the future, with the increase in manufacturers that can produce qualified NCM811 , the gross profit margin of NCM811 products will tend to decline.
.2 Analysis of cost sensitivity of ordinary and high-nickel ternary materials
.2.1 The impact of changes in price changes in cobalt and lithium sources on the ton cost of NCM523
.2.5 Changes in raw material prices have greater impact on NCM523 than NCM811
In the above four tables, we analyzed the sensitivity of the cost of two ternary materials of NCM523 and NCM811 to raw materials and prices. The analysis results are as follows:
(1) Based on the current raw material prices, the price increase of cobalt sulfate heptahydrate by 10,000 yuan/ton will drive the cost of NCM523 positive electrode material to rise by 5.02%, driving the cost of NCM811 positive electrode material to rise by 1.94%. Since the cobalt content in NCM523 is higher than NCM811, NCM523 is greatly affected by the cobalt price; in addition, the price increase of lithium carbonate by 10,000 yuan/ton will drive the cost of NCM523 positive electrode material to rise by 3.24%, and the price increase of lithium hydrogen oxide by 10,000 yuan/ton will drive the cost of NCM811 positive electrode material to rise by 2.98%.
(2) At the current raw material price level, the ton cost of NCM811 is higher than that of NCM523, but since the cobalt content of NCM523 is higher than that of NCM811, the change in the cobalt price has a greater impact on the cost of NCM523. If the cobalt price rises sharply, the cost gap between the two will gradually narrow. When the price of cobalt sulfate heptahydrate reaches 1.15 ,000 / tons, the costs of the two will converge. If the price of cobalt sulfate heptahydrate continues to rise, the ton cost of NCM523 will be higher than that of NCM811.
(3) At the current raw material price level, the kwh cost of NCM811 is lower than that of NCM523. The same as above, the impact of the price changes of cobalt sulfate heptahydrate on the kwh cost of NCM523 is greater than that of NCM811. When the price of cobalt sulfate decreases, the cost gap between the two gradually narrows. When the price of cobalt sulfate heptahydrate falls to about ,000 / tons, the costs of the two converge. If the price of cobalt sulfate heptahydrate continues to fall, the cost of NCM811 will be higher than that of NCM523.
.2.6 Reducing the electricity consumption price will have a positive impact on cost reduction and efficiency of positive electrode materials
In the following table, we analyzed the sensitivity of the two ternary materials costs of NCM523 and NCM811 to electricity consumption. The analysis results are as follows:
(1) Based on the current electricity price, the electricity price changes by 0.1 yuan/kwh, the NCM523 cost changes by 1.05%, and the NCM811 cost changes by 1.18%, mainly because the electricity consumption of NCM811 is higher than that of NCM523.
(2) In areas with low electricity prices, industrial electricity prices can be as low as about 0.4 yuan/kwh. If a factory is built locally, the costs of NCM523 cathode material and NCM811 cathode material can be reduced by 3.96% and 4.50% respectively. Therefore, the factory construction address of the cathode material must consider the local electricity prices, which will have a positive impact on the cost reduction and efficiency of ternary materials.
. to 020 overall supply and demand for high-nickel materials in the past year is tight, and the short-term focus is expected to be biased towards NCM622
.1 Supply side: The market concentration of ternary materials has increased, and there are many plans for high-nickel materials expansion
We count the total production capacity of ternary materials and high-nickel materials (mainly for NCM622 and above) in the following table.
statistics show that the total production capacity of ternary materials of mainstream domestic manufacturers has exceeded 140,000 tons/year, but the overall dispersion of the positive electrode materials market structure is relatively high. According to SMM statistics, as of 018 , the total production capacity of domestic ternary materials was 3.67 ,000 tons, an increase of 2.93 ,000 tons compared with 017 . The increase comes from Hunan Shanshan, Beijing Dangsheng, Tianjin Bamo, Xiamen Xia Tungsten, Jingmen Greenmei, Ningbo Rongbai, Guizhou Zhenhua, Sichuan Science and Technology Energy, Jiangsu Xiangying, Sinochem Hebei, Hunan Bangpu, Yibin Lithium Treasure and other companies (ranking in no particular order).
In addition, the total production capacity of high-nickel materials by domestic mainstream manufacturers has exceeded 20,000 tons of html, and the subsequent large-scale expansion plans of mainstream manufacturers are mainly aimed at high-nickel ternary materials, among which the expansion plans of NCM811 and NCA are mostly.
According to Xinliu Information on the output statistics of 28 domestic ternary material companies, the output of ternary material in 2018 was 165,000 tons, a year-on-year increase of 26%. Specifically at the enterprise level, among the 28 companies counted by Xinli Information, 7 companies with output of over 10,000 are Dangsheng Technology, Youmeike, Ningbo Rongbai, Changyuan Lithium Technology, Xiamen Tungsten Industry , Hunan Shanshan, and Guizhou Zhenhua. Among them, Guizhou Zhenhua, Dangsheng Technology, Changyuan Lithium Technology, and Xiamen Tungsten Industry are new entry in 2018. According to statistics, in 017 , China's ternary materials CR5 was 9.7% , CR10 was 5.8% ; in the first half of , domestic ternary materials CR5 was 1.0% , CR10 was 5.9% , and market concentration slightly increased.
.2 Demand side: The proportion of high nickel in total installed capacity will increase year by year
We make a demand forecast based on the key data of the new energy vehicle and lithium battery industry chain in 2018 and based on the judgment of the future trend of the new energy vehicle industry. As shown in Table 29, the basic assumptions are as follows:
(1) The calculation only considers the demand for power batteries, but does not consider the demand for 3C and energy storage fields;
(2) In the 2018 data, the production of new energy vehicles, installed power batteries, installed power batteries, installed ternary batteries, and shipment volume of various types of ternary batteries are known, and the average power of a bicycle, penetration rate of ternary batteries, penetration rate of each type of ternary battery and demand data are all calculated based on known data;
(3) Based on our judgment on the future trend of the new energy vehicle industry, we assume that the output of new energy vehicle continues to rise, and the output data in 2020 is expected to exceed policy requirements; the average power of a bicycle continues to rise; the penetration rate of ternary batteries continues to grow, among which the proportion of high-nickel batteries will increase significantly.
calculation results show that from 018 to -2020 , the total installed capacity demand for ternary materials was .13 tons, .54 tons and 4.01 tons, among which the installed capacity demand for high-nickel materials was .23 tons, .90 tons and .13 tons, respectively, and the proportion of total demand increased year by year. Comparing the supply data in the previous section, it can be seen that the current domestic high-nickel material production capacity is around 20,000 tons of html, while the actual release value is lower than 20,000 tons of . In addition, the high-nickel production lines of most high-end product manufacturers are still supplying NCM523 products, and the actual supply volume has further shrunk. Even if the new capacity of manufacturers is continuously released, it will take time to climb the new capacity. Therefore, by 020 , the overall supply and demand of high-nickel materials are in a tight state. In addition, there are two factors that may cause the actual demand for high nickel materials to be greater than the calculated value. First, our current calculation only considers the demand for power batteries, but does not consider the demand for C field and the possible future energy storage field demand; second, our current calculation is only based on installed capacity data, and the actual shipment of power batteries may be significantly greater than the installed capacity, and the actual demand will be further amplified. According to the category of high nickel materials, since the current policy's attitude towards increasing energy density has slowed down slightly and the importance of safety has further increased, the development of high nickel materials may be biased towards NCM622, NCM811 and NCA in a short period of time, but given the demand side's pursuit of high nickel and lightweight automobiles, the long-term trend of high nickel has remained unchanged.
. Discussion on the safety of ternary positive electrode materials
In the past two years, spontaneous fire accidents of new energy vehicles have occurred frequently, and the safety of new energy vehicles has become one of the biggest concerns in consumers' purchasing process. The following table lists the fire accidents and causes of domestic new energy vehicles from 2017 to August 2018.
First of all, we need to be clear that the application of ternary materials is not the direct cause of the fire of new energy vehicles. According to data, the flammable substances in lithium batteries are electrolytes, and there are various causes of fire. It is just that batteries using
ternary materials are more likely to ignite the electrolyte when there is a problem. Therefore, there is no need for us to give up and deny the application of ternary materials.
However, the frequent spontaneous combustion of new energy vehicles is indeed related to the application of high-nickel materials, or rather, it is related to the frequent increase in the technical threshold of new energy vehicles. Before 019 , the policy orientation of new energy vehicles was mainly to continuously raise the technical threshold requirements while the subsidy amount was reduced. The most important one was the requirements for the mileage range of new energy vehicles and the energy density of power battery systems. The positive electrode material was one of the most important factors that determine the energy density, which greatly promoted the development of positive electrode materials toward higher nickelization. There are two problems in this process: First, as we mentioned above, the higher the nickel content of the ternary positive electrode materials and the lower the manganese content, the worse its stability and the greater the hidden dangers; Second, according to the data, in addition to the improvement of the energy density of lithium batteries, in addition to the greater the improvement of the positive electrode and negative electrode materials, there are also technical research on matching high voltage electrolytes, high-temperature high-strength separators, lithium supplementation process, battery safety control structure, system protection structure and other technical research. The solution of these problems requires close attention. 24-28 months, and the current policy orientation is that the threshold is raised every year, which is a bit hasty. The technical maturity of each material may not have reached the actual application stage yet, and the security verification cycle is still relatively short, and the possibility of problems is relatively high.
019 subsidy policy has slowed down the requirements for energy density of various types of vehicles. First, the passenger car subsidy standard has added the live quantity indicator to balance the technical level of new energy vehicles from the policy end; second, although the threshold for energy density of passenger cars continues to increase, the highest standard has not been further improved, and the policy no longer sets excess subsidies for energy density exceeding 1 times, avoiding excessive pursuit of high subsidy amounts and ignoring other performance indicators; third, the classification standard for subsidy adjustment coefficient of non-fast charging pure electric passenger cars has changed from the system energy density to the unit mass energy consumption, which weakens the impact of the energy density indicator at the passenger car level; fourth, the threshold requirement that the total mass of the new energy bus battery accounts for the proportion of the curb mass of the vehicle (m/m) is not higher than 20%, which to a certain extent curbs the blind pursuit of high energy density to a certain extent. Poor direction of power batteries. As mentioned above, we believe that the change in policy attitude towards high energy density in the short term mainly comes from the immaturity of high-nickel technology and the emphasis on safety, rather than the weak demand side, resulting in the demand side. In fact, consumers' pursuit of mileage and lightweight of new energy vehicles is still an important factor affecting consumers' purchasing mentality. Therefore, the current platform period is actually making full preparations for the large-scale increase in high-nickel materials with nickel content higher than 0% in the future, and the long-term trend of high-nickelization remains unchanged. The current trade-off between policy and market is expected to benefit high-transition nickel-low-cobalt products, such as NCM613 and NCM712, while controlling the reasonable nickel content, reducing cobalt content and controlling costs, increasing manganese content and enhancing stability.
In addition, even if we do not consider the application of high-nickel ternary materials, we will discuss the lithium iron phosphate positive electrode material that is generally believed to be safer. The current installed average battery cell density has reached 160Wh/kg, and the battery pack energy density is close to 134Wh/kg, and the grouping efficiency is very high, even reaching more than 90%. The safety performance of such battery cells is also worrying. Since ternary materials mainly increase the system energy density by increasing the battery cell energy density rather than by improving the grouping efficiency, the grouping efficiency of the ternary materials is not as high as lithium iron phosphate, which is about 65%. In summary, the problem of safety performance mainly lies in the trade-off of mileage (or energy density) and the rhythm of technological progress, rather than directly determined by the application of ternary materials and even high-nickel ternary materials.
