Shulou(Shulou.com)11/24 Report--

Original title: "Lithium-thinking liquid"

The outbreak of the new energy vehicle market has led to the success of lithium batteries and the upgrading of raw materials upstream.

In the previous article, "Why is the film of lithium battery so expensive?" Fruit shell hard technology has combed one of the four main materials, lithium battery diaphragm related information. In this article, we will turn our attention to another of the "four Heavenly Kings", which is known as the electrolyte of the "blood" of lithium batteries.

What is the electrolyte? Electrolyte, as one of the four main materials of lithium battery (the other three are positive electrode, negative electrode and diaphragm), is the carrier of ion transmission in lithium battery, which conducts lithium ion between positive and negative electrodes and provides an environment in which lithium ion can be removed freely. it has an important impact on the energy density, specific capacity, working temperature range, cycle life, safety performance and so on.

Compared with the lithium battery separator analyzed in the previous part, the performance index of the electrolyte is less, mainly in four aspects: electrical conductivity, chemical stability, usable temperature range and safety.

Source of information: Kangpeng Technology prospectus [1] is affected by the price of upstream raw materials, there are some differences in the specific cost composition of lithium battery in different periods, and the fluctuation of electrolyte price is more obvious than that of other materials. therefore, the percentage change in the total cost of the battery is more obvious, usually fluctuating around 10% and 15% [2] [3].

The mainstream lithium battery electrolyte is usually prepared by electrolyte lithium salts (solutes), high-purity organic solvents, various additives and other raw materials in a certain proportion.

Source of information: Pengkang Technology prospectus [1] the three main components of the electrolyte are arranged according to the mass ratio, respectively: solvent accounts for about 80% 85%, lithium salt accounts for 10% 15%, additive 5% above and below [2] [4] [5] [6]. But the cost proportion of the three raw materials is completely different, the core lithium salt accounts for the highest, at this stage can reach about 50% 60%; additives 10% 20%; solvents are about 25%.

It must be emphasized that this cost structure is only estimated. The raw material prices of electrolytes have fluctuated greatly in recent years. For example, the price of mainstream lithium salt lithium hexafluorophosphate has halved from the high point at the beginning of the year, and the price of common solvents has dropped by more than 60%. On the other hand, the electrolyte is highly customized. there is no unified standard, and it is difficult to give accurate calculation for different customers' products in terms of materials. Overall, the cost of electrolyte raw materials accounts for about 80%, which is much higher than other main materials of lithium batteries [4] [5] [6] [7] [8].

The production process of electrolyte itself is not complex, and the proportion of processing cost in the total cost is not high. The production process of electrolyte is mainly composed of solvent preparation, solvent purification, preparation, post-treatment and filling. Among them, the preparation means that according to the formula of the electrolyte and the order in which the materials are added, the purified solvents, solutes, additives and other raw materials are fully stirred and mixed in the preparation kettle, which directly determines the performance index of the electrolyte and is the core of the electrolyte production process. Due to the simple process, the industry threshold of the electrolyte is low, the fixed investment of GWh estimated by securities firms is only 3.42 million yuan, far lower than the average of 57.98 million yuan in other links of the lithium industry chain, resulting in a certain low-end overcapacity in the industry, but also makes the processing link can not reflect the competitiveness of leading enterprises [4].

The core competitiveness of electrolyte mainly comes from cost control ability and formula, which is a more obvious advantage of leading enterprises. As mentioned earlier, more than 80% of the cost of the electrolyte is the cost of raw materials, and the price of raw materials will directly affect the profitability of enterprises, so enterprises with layout of upstream core raw materials or stronger bargaining power tend to have stronger competitiveness.

The formula directly determines the specific composition ratio of the electrolyte and directly determines the final performance of the product, that is, the competitiveness of the product. At present, the main sources of formulations are independent research and development by electrolyte manufacturers, cooperative research and development with battery manufacturers, and provided by battery manufacturers, so the competitiveness of electrolyte enterprises with fixed downstream cooperative customers or strong self-research ability is more prominent.

The science and technology of liquid and the three kinds of core materials of electrolyte: solute (lithium salt), solvent and additive are a series of substances used to prepare electrolyte, which involve a lot of raw materials, and solvents and additives are in pursuit of better performance. it is usually a mixture of several materials, which makes the appearance of the electrolyte system relatively complex, and mouthful terms and various abbreviations can be seen everywhere.

This section will analyze the three core components of the electrolyte in a manner that is as easy to understand as possible.

Lithium salt, that is, the solute in the electrolyte, is the core component of the electrolyte with the highest cost. Its main function is to provide lithium ion and transfer lithium ion between positive and negative electrodes, which has a decisive influence on the physical and chemical properties of the electrolyte, including ion mobility, dissociation constant, solubility, thermal stability, chemical stability, SEI film forming ability and so on.

SEI film: that is, solid electrolyte interface film, solid electrolyte interphase for short. It means that during the first charge and discharge of liquid lithium ion battery, the electrode material reacts with the electrolyte at the solid-liquid interface to form a passivation layer covering the surface of the electrode material. This passivation layer is an interface layer, which has the characteristics of solid electrolyte, and is an electronic insulator but an excellent conductor of Li +. Li + can be embedded and released freely through this passivation layer [9].

Although there are many kinds of lithium salts, the ones suitable for lithium batteries are limited, including lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium difluorosulfonimide (LiFSI), lithium dioxalate borate (LiBOB), lithium difluoroxalate borate (LiDFOB), lithium difluorophosphate (LiPO2F) and lithium bis trifluoromethylsulfonimide (LiTFSI).

Lithium hexafluorophosphate (LiPF6) is the most mainstream electrolyte for lithium battery. It has suitable solubility, high conductivity, good ion transfer number, strong electrochemical stability and oxidation resistance in non-aqueous solvents, and can form appropriate SEI film on carbon negative electrode and effectively passivate positive aluminum foil. Mature large-scale production also highlights its cost advantage. Although the single index of lithium hexafluorophosphate may not be the best, the comprehensive price ratio is very outstanding and is widely favored by manufacturers.

Interestingly, the preparation of the electrolyte itself is not complex, but lithium hexafluorophosphate, as the mainstream lithium salt, is completely different, the process is tedious and difficult [10].

At present, the most mainstream preparation process of lithium hexafluorophosphate is HF (hydrogen fluoride) solvent method, which has the advantages of rapid reaction, high conversion rate, simple process, high product purity and suitable for large-scale production. Simply put, the process consists of the reaction of phosphorus pentachloride (PCl5) with anhydrous hydrogen fluoride (HF) to produce phosphorus pentafluoride (PF5) gas, which then reacts with lithium fluoride (LiF) dissolved in anhydrous hydrogen fluoride to form lithium hexafluorophosphate (LiPF6) [11].

But the defect of HF solvent method is that lithium hexafluorophosphate is very unstable and decomposes at about 60 ℃, and a very small amount of water will also lead to decomposition, the preparation needs to be carried out in anhydrous solvent, the working conditions are very stringent, the purity of raw materials is also very high, and the raw materials contain hydrogen fluoride, which is a highly corrosive substance, and there are also high requirements for production equipment. In short, the comprehensive production difficulty, capital investment and energy consumption of HF solvent method are outstanding, and the cost is not ideal.

At present, it is hopeful that the alternative production process of lithium hexafluorophosphate by HF solvent method is organic solvent method. The advantage of this process is that the dangerous hydrogen fluoride is replaced by non-corrosive organic solvents, which is safer to operate and requires less equipment, thus reducing the expenditure on fixed assets. At the same time, the reaction of organic solvent method can be carried out at room temperature and pressure, the working condition is not strict, and the crystallization process is omitted, which can realize continuous production and improve production efficiency. The defect is that it is difficult to produce high purity lithium hexafluorophosphate, and the final product is liquid, and the transportation of liquid lithium hexafluorophosphate is very difficult. At present, Tianci material is a mature application of this process, there are certain leading advantages of electrolyte production enterprises.

In addition to causing some trouble in the preparation process, lithium hexafluorophosphate has poor thermal stability and easy hydrolysis, which also leads to rapid decomposition once the temperature or water content is too high. As a result, the battery capacity is rapidly reduced and harmful by-products are released, causing safety risks. This defect has prompted electrolyte manufacturers to look for new lithium salts with better performance under the background of higher and higher requirements for various indicators of lithium batteries from downstream battery manufacturers and automobile companies.

The new lithium salts mainly include lithium difluorosulfonimide, lithium difluorophosphate and lithium tetrafluoroborate, among which difluorosulfonimide (LiFSI) is the most concerned and has the highest commercial certainty in the future, so it is regarded as a strong competitor of the next generation of mainstream lithium salt. Compared with lithium hexafluorophosphate (LiPF6), LiFSI has higher electrical conductivity, chemical stability and thermal stability, and can significantly improve the low temperature performance, cycle life and high temperature resistance of the battery.

However, at this stage, the process of LiFSI is still too complex, and the cost is too high, which leads to low economy. It is mainly used as an additive rather than as a solute. However, the advantages of LiFSI have attracted enough attention in the industry, and many leading enterprises have paid attention to and distributed this new type of lithium salt, and the trend of production expansion has emerged. With the continuous development of the future production process, the further reduction of cost, and the gradual landing of enterprise production capacity, LiFSI is very hopeful to rewrite the industry pattern of electrolyte solute.

Additives are substances with specific functions in the electrolyte, which account for the lowest proportion of mass, but play an important role in improving the specific properties of the electrolyte. As different application fields and different downstream customers have different requirements for lithium battery performance, electrolyte manufacturers can improve the performance of lithium battery by adjusting the type and dosage of additives. There are many kinds of additives, which can be divided into film-forming additives, overcharge protection additives, high and low temperature additives, flame retardant additives, additives to control the content of water and HF and so on.

Source: Huasheng Lithium prospectus [12] the common additives are mainly vinylidene carbonate (VC), fluoroethylene carbonate (FEC) and 1min3-propane sulfonolactone (1d3-propane sulfonolactone), which accounted for nearly 82% of the total shipments in the domestic market in 2020. The general characteristic of additives is that the market is small, the production process is very complex, and the added value is very high. It is a very typical seller's market special chemical [13].

Solvents, mainly used as carriers for transporting lithium ions, are the components with the highest mass in the electrolyte (about 80%), but their importance is slightly lower than that of lithium salts and additives. The commonly used solvents can be roughly divided into three types: carbonate, sulfite and sulfone, among which carbonate products are the most widely used electrolyte solvents because of their outstanding performance and cost. According to their different structures, carbonates can be further divided into cyclic carbonate organic solvents and chain carbonate organic solvents. The former includes vinyl carbonate (EC) and propylene carbonate (PC), while the latter is mainly dimethyl carbonate (DMC), diethyl carbonate (DEC) and methyl ethyl carbonate (EMC).

Further looking at the specific products, the most common electrolyte products at the present stage are the mixture of the above five kinds of carbonates, in which dimethyl carbonate (DMC) has the advantages of low odor, good volatility, strong solubility, high electrical conductivity, good low temperature charge and discharge performance and low cost, and is the electrolyte solvent with the highest market permeability.

The electrolyte solvent can be divided into industrial grade and battery grade, and the industrial grade purity is required to be 99.9%. Because the electrolyte impurities will have a direct impact on the battery performance, the battery grade purity is required to reach at least 99.99% or even 99.995%. It is the core index of the solvent, and the corresponding process is very difficult [13] [14].

There are many synthetic routes of carbonate solvents, and the current mainstream route is transesterification, which is commonly known as petrification. The preparation method has the advantages of simple process, high reaction efficiency, low production cost and high purity of the final product, and the product can be directly used in lithium battery electrolyte after purification and impurity removal.

Other production processes of carbonate solvents include:

Phosgene process: the raw materials of this process involve highly toxic substances, serious environmental pollution, great difficulty in environmental assessment, low production safety, not in line with the basic trend of industrial development, and have been basically eliminated.

Methanol oxidative carbonyl method: the raw materials are easily available, the production cost is low, the production process is simple and relatively environmentally friendly, but the production efficiency is low and the requirements for production equipment are relatively high, so it is one of the concerned technical routes.

Urea alcoholysis: the raw materials are easy to obtain, the conversion efficiency is good and the by-products can be recycled, and the reaction is very green and environmentally friendly, but the reaction is very difficult and requires extremely expensive catalysts. at the present stage, the economy is poor, and it is also a technical route that has attracted more attention.

Carbon dioxide synthesis method: the raw material cost is extremely low, the production process is safe and environmentally friendly and there are few links, but the technology is very immature and is still in the laboratory stage.

The liquid state of lithium battery benefits from the rapid development of the power battery industry, and the electrolyte has also achieved a great-leap-forward growth in the market scale in recent years.

According to EV Tank data, China's electrolyte shipments in 2020 were 269000 tons, an increase of 35.9% over the same period last year, while in 2021, domestic shipments rose significantly to 507000 tons, an increase of 88.5% over the same period last year [15]. According to GGII data, domestic electrolyte shipments reached 330000 tons in the first half of 2022, an increase of 63% over the same period last year.

China, as always, occupies a dominant position in the field of electrolyte with the advantage of manufacturing industry. In 2020, the global electrolyte shipment was 334000 tons, and the proportion of domestic shipments was 80.54%. In 2021, the global shipments were 612000 tons, while the proportion of domestic shipments increased significantly to 88.5% [15].

However, it should be emphasized that this shipment data refers to the overall shipment of electrolytes, not power battery electrolytes, as well as digital and energy storage markets. By product, power battery electrolytes accounted for 52% of the market in 2020, barely more than half, and reached 62% in 2021, and shipments further increased to 70% [16] [17] in the first half of 2022. This change in the market undoubtedly reflects the extremely strong demand in the power battery market, but it is also related to the malaise of the digital market, while the energy storage scenario benefits from the fast-growing clean energy industry and helps overall growth. however, due to the small size, it is not as obvious as the power battery market.

From the perspective of market competition pattern, electrolyte is a typical oligopoly market, and its market share is highly concentrated to the head enterprise. According to GGII data, the CR3 of the domestic electrolyte market in 2022 / 2021 / 2022, H1 was 61% / 62% / 61% respectively, and the CR6 in the same period was 77% / 75% / 74% respectively. Although affected by the epidemic, order spillover caused by strong downstream demand and other factors, the market concentration of the industry fluctuated, but remained at a high level [16] [17].

As the statistical caliber of the electrolyte industry is relatively large, and the data are relatively confused, this paper does not give specific data. However, no matter which statistical method is used, Divine Materials, New Zebang and Guotai Huarong (a subsidiary of Jiangsu Cathay Pacific, a listed company) are firmly in the top three positions, among which Divine Materials has a great advantage over the latter two, living alone in the first echelon. New Zebang and Cathay Huarong ranked second and third, while the third echelon included Cedar shares, Farnlet, BYD (self-produced), Kunlun Chemical, Sinochem Blue Sky, Saiwei Electronics and other enterprises.

Whether technical iteration is a thing or not, although the electrolyte field has developed extremely rapidly in recent years due to the extremely strong downstream demand, and the production enterprises have made a lot of money, there is still clear technical iterative pressure in the industry.

At present, the very hot solid-state battery and the semi-solid state whose industrialization path has been relatively clear are the changes made for this part of the electrolyte. The former is the complete use of solid electrolytes, completely abandon the electrolyte, the technological maturity is still not high, facing many technical thresholds, research and development is difficult, there is still a long distance from large-scale; the latter is "slightly" milder, the mixed use of solid-liquid electrolytes, comprehensive cost and technical difficulty considerations, may be more in line with commercial needs.

There is no doubt that the brand-new solid / semi-solid battery is a relatively clear trend in the industry, but there is no final conclusion on the final form of the product, which will affect the operation of electrolyte enterprises to a certain extent. For example, polyfluorodo mentioned on the investor interaction platform that the sulphide route does not even need the current mainstream lithium salt, while the PEO (poly (ethylene oxide) electrolyte route has a certain demand for existing electrolytes. Due to the smaller difference between semi-solid and current lithium battery technology, semi-solid still has a clear demand for electrolyte.

Source: interactive easy [18] [19] of course, major enterprises in the industry have paid attention to this trend. on the investor interaction platform, they have repeatedly said that they have carried out relevant technology research and development, have some patents, are following the technology development trend, and that the products can be directly used in the next generation battery technology, but they also mention that they are facing many difficulties.

Source of information: interactive easy [20] [21] [22] [23] but from another point of view, technology also has its own law of development, and the development of solid / semi-solid or other new batteries cannot be achieved overnight. It can only be said that it is a relatively deterministic future technology route. We can foresee that some changes will inevitably take place in the format of the industry. The old leading enterprises need to make some changes, and there will be plenty of opportunities for new entrants, but on the whole, these will not happen in the short term. There will be no fundamental changes in the industry logic and business model at this stage. What is needed is to pay more attention to the landing of technology rather than excessive worry.

If we turn our attention to other broader new battery technology routes, we will find that the roles of electrolytes are more diversified.

For sodium batteries with high heat recently, the role and development trend of electrolytes are not much different from lithium batteries. Sodium is a cheap substitute for lithium, the working principle of battery and battery structure is also very close to lithium battery, and the compatibility of production equipment is relatively high. Sodium battery also has a relatively clear development direction of semi-solid and solid state. Generally speaking, the industry experience of lithium battery electrolyte can be used for reference for sodium battery electrolyte. For example, sodium hexafluorophosphate is also the most commonly used electrolyte for sodium battery, corresponding to lithium hexafluorophosphate [24]. The impact of this route on the overall electrolyte is not necessarily greater than that of solid / semi-solid.

However, in other directions, the specific positioning of the electrolyte has changed greatly.

For example, the structure of vanadium flow battery is completely different from that of lithium battery, and the electrolyte is directly used as the positive and negative active material of the battery, mainly the solution containing vanadium ion. Electrolyte is the most important material for liquid flow battery, and its concentration and volume directly determine its capacity, which also means that it accounts for a very high proportion of the cost, and the proportion of electrolyte in the 4-hour energy storage system can reach 50%; the longer the time, the proportion can be further increased [25].

As for the fuel cell route led by hydrogen fuel cell, it no longer belongs to storage battery, has fundamental technical differences, and does not involve the concept of electrolyte.

In short, the analysis of the development trend of the electrolyte industry requires more extensive consideration of the downstream battery industry. Due to the complexity of the technical route, the application of different batteries to the electrolyte is very different, and may not represent the most mainstream battery form in the future. A more likely landing mode of the battery industry in the future is that the products are highly specialized for specific application scenarios, and different forms of batteries coexist. Overemphasizing or ignoring the changes brought about by technological iterations will pose a certain risk to both industry participants and investors, and it is necessary to fully combine the specific technical route in order to draw a more accurate conclusion.

References:

[1] Shanghai Kangpeng Technology Co., Ltd.: initial public offering and listing prospectus of Science and Technology Innovation Board (draft) 2021.03

[2] Anxin Securities: the bottom of electrolyte profit, fluorine chemical industry can be expected to be 2022.11.08

[3] head Leopard Research Institute: Overview of China's electrolyte industry in 2022: high prosperity of the industry, new lithium salt brings industry change 2022.03

[4] Shen Wanhongyuan: global electrolyte leader, continuously deepening the vertical layout of the industrial chain 2022.02.15

[5] Shengang Securities: global electrolyte leader integrated production expansion to ensure growth 2022.11.01

[6] Huaan Securities: the supply and demand of the electrolyte industry chain is booming, and the strong leading company Hengqiang 2022.09.15

[7] Xiangcai Securities: the demand prospect of core materials for electric vehicles is broad, and the material system is constantly iterated and innovated 2022.08.24.

Zhou Quan: according to the analysis of the current situation of the global and Chinese electrolyte solute (lithium salt) industry in 2021, the price of lithium hexafluorophosphate may fall back in 22. Huajing Information Network 2022.04.08 https://www.huaon.com/ channel / trend / 796355.html

[9] interpretation of practical information: with such a complete introduction of the SEI film, there is really no longer an introduction to the SEI film on December 18, 2017.12, 2012, 2012, 2011, December 18, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 2017.12, 51cc496a51ced7ced7aa4cd2617182c1, ampampfield, sourceworthy, 41wechatredirect

[10] Huaan Securities: deep ploughing electrolyte Solute Competition to create a New Materials Industry platform 2022.08.05

[11] Bank of China Securities: lithium hexafluorophosphate Industry depth report 2020.09.16

[12] Huasheng Lithium Power: initial public offering and letter of intent in Science and Technology Innovation Board's listing 2022.06.24

[13] Qianhai of East Asia: new energy vehicles + energy storage two-wheel drive, electrolytic liquid scene bearing is expected to continue 2022.09.22

[14] Guotai Junan: based on the integration of light hydrocarbons, the construction increment of new materials is 2022.11.09

[15] China's lithium-ion battery electrolyte shipment reached 507000 tons in EVTank:2021, and the industry chain vertical integration trend is obvious 2022.03.04 https://mp.weixin.qq.com/ s / tFaszufwudJ-gMaJXguGcg.

[16] GGII:2022H1 China shipped 330000 tons of electrolytes, an increase of more than 60% over the same period last year. New industry think tank 2022.07.21 https://mp.weixin.qq.com/ s / ob23J8eqeCF3T9RVQvIuLg

[17] GGII:2021 China shipped 500000 tons of electrolyte, an increase of 100% over the same period last year. High-tech lithium power grid 2022.04.08 https://www.gg-lb.com/ art-44603.html

[18] Interactive easy 2021.12.10 http://irm.cninfo.com.cn/ ircs / question / questionDetail?questionId=1068216701282906112

[19] Interactive easy 2022.02.10 http://irm.cninfo.com.cn/ ircs / question / questionDetail?questionId=1114426444741427200

[20] Interactive easy 2022.07.22 http://irm.cninfo.com.cn/ ircs / question / questionDetail?questionId=1234593770007027712

[21] Interactive easy 2022.07.20 http://irm.cninfo.com.cn/ ircs / question / questionDetail?questionId=1233305288408354816

[22] Interactive easy 2022.08.26 http://irm.cninfo.com.cn/ ircs / question / questionDetail?questionId=1260870200876908544

[23] Interactive easy 2021.12.01 http://irm.cninfo.com.cn/ ircs / question / questionDetail?questionId=1061759406931931136

Zhang fuming, Wang Jing, Zhang Peng, Shi Zhiqiang. Research progress of organic electrolyte in sodium ion battery. Materials Engineering, 2021, 49 (1): 11-22.

[25] Everbright Securities: vanadium Battery Series report 3 2022.09.25

This article comes from the official account of Wechat: fruit Shell hard Technology (ID:guokr233), author: Chen Julei, Editor: Li Tuo

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